clang 19.0.0git
CFG.cpp
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1//===- CFG.cpp - Classes for representing and building CFGs ---------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the CFG and CFGBuilder classes for representing and
10// building Control-Flow Graphs (CFGs) from ASTs.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Analysis/CFG.h"
16#include "clang/AST/Attr.h"
17#include "clang/AST/Decl.h"
18#include "clang/AST/DeclBase.h"
19#include "clang/AST/DeclCXX.h"
20#include "clang/AST/DeclGroup.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
25#include "clang/AST/Stmt.h"
26#include "clang/AST/StmtCXX.h"
27#include "clang/AST/StmtObjC.h"
29#include "clang/AST/Type.h"
35#include "clang/Basic/LLVM.h"
39#include "llvm/ADT/APInt.h"
40#include "llvm/ADT/APSInt.h"
41#include "llvm/ADT/ArrayRef.h"
42#include "llvm/ADT/DenseMap.h"
43#include "llvm/ADT/STLExtras.h"
44#include "llvm/ADT/SetVector.h"
45#include "llvm/ADT/SmallPtrSet.h"
46#include "llvm/ADT/SmallVector.h"
47#include "llvm/Support/Allocator.h"
48#include "llvm/Support/Casting.h"
49#include "llvm/Support/Compiler.h"
50#include "llvm/Support/DOTGraphTraits.h"
51#include "llvm/Support/ErrorHandling.h"
52#include "llvm/Support/Format.h"
53#include "llvm/Support/GraphWriter.h"
54#include "llvm/Support/SaveAndRestore.h"
55#include "llvm/Support/raw_ostream.h"
56#include <cassert>
57#include <memory>
58#include <optional>
59#include <string>
60#include <tuple>
61#include <utility>
62#include <vector>
63
64using namespace clang;
65
67 if (VarDecl *VD = dyn_cast<VarDecl>(D))
68 if (Expr *Ex = VD->getInit())
69 return Ex->getSourceRange().getEnd();
70 return D->getLocation();
71}
72
73/// Returns true on constant values based around a single IntegerLiteral.
74/// Allow for use of parentheses, integer casts, and negative signs.
75/// FIXME: it would be good to unify this function with
76/// getIntegerLiteralSubexpressionValue at some point given the similarity
77/// between the functions.
78
79static bool IsIntegerLiteralConstantExpr(const Expr *E) {
80 // Allow parentheses
81 E = E->IgnoreParens();
82
83 // Allow conversions to different integer kind.
84 if (const auto *CE = dyn_cast<CastExpr>(E)) {
85 if (CE->getCastKind() != CK_IntegralCast)
86 return false;
87 E = CE->getSubExpr();
88 }
89
90 // Allow negative numbers.
91 if (const auto *UO = dyn_cast<UnaryOperator>(E)) {
92 if (UO->getOpcode() != UO_Minus)
93 return false;
94 E = UO->getSubExpr();
95 }
96
97 return isa<IntegerLiteral>(E);
98}
99
100/// Helper for tryNormalizeBinaryOperator. Attempts to extract an IntegerLiteral
101/// constant expression or EnumConstantDecl from the given Expr. If it fails,
102/// returns nullptr.
104 E = E->IgnoreParens();
106 return E;
107 if (auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
108 return isa<EnumConstantDecl>(DR->getDecl()) ? DR : nullptr;
109 return nullptr;
110}
111
112/// Tries to interpret a binary operator into `Expr Op NumExpr` form, if
113/// NumExpr is an integer literal or an enum constant.
114///
115/// If this fails, at least one of the returned DeclRefExpr or Expr will be
116/// null.
117static std::tuple<const Expr *, BinaryOperatorKind, const Expr *>
120
121 const Expr *MaybeDecl = B->getLHS();
122 const Expr *Constant = tryTransformToIntOrEnumConstant(B->getRHS());
123 // Expr looked like `0 == Foo` instead of `Foo == 0`
124 if (Constant == nullptr) {
125 // Flip the operator
126 if (Op == BO_GT)
127 Op = BO_LT;
128 else if (Op == BO_GE)
129 Op = BO_LE;
130 else if (Op == BO_LT)
131 Op = BO_GT;
132 else if (Op == BO_LE)
133 Op = BO_GE;
134
135 MaybeDecl = B->getRHS();
137 }
138
139 return std::make_tuple(MaybeDecl, Op, Constant);
140}
141
142/// For an expression `x == Foo && x == Bar`, this determines whether the
143/// `Foo` and `Bar` are either of the same enumeration type, or both integer
144/// literals.
145///
146/// It's an error to pass this arguments that are not either IntegerLiterals
147/// or DeclRefExprs (that have decls of type EnumConstantDecl)
148static bool areExprTypesCompatible(const Expr *E1, const Expr *E2) {
149 // User intent isn't clear if they're mixing int literals with enum
150 // constants.
151 if (isa<DeclRefExpr>(E1) != isa<DeclRefExpr>(E2))
152 return false;
153
154 // Integer literal comparisons, regardless of literal type, are acceptable.
155 if (!isa<DeclRefExpr>(E1))
156 return true;
157
158 // IntegerLiterals are handled above and only EnumConstantDecls are expected
159 // beyond this point
160 assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
161 auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
162 auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
163
164 assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
165 const DeclContext *DC1 = Decl1->getDeclContext();
166 const DeclContext *DC2 = Decl2->getDeclContext();
167
168 assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
169 return DC1 == DC2;
170}
171
172namespace {
173
174class CFGBuilder;
175
176/// The CFG builder uses a recursive algorithm to build the CFG. When
177/// we process an expression, sometimes we know that we must add the
178/// subexpressions as block-level expressions. For example:
179///
180/// exp1 || exp2
181///
182/// When processing the '||' expression, we know that exp1 and exp2
183/// need to be added as block-level expressions, even though they
184/// might not normally need to be. AddStmtChoice records this
185/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
186/// the builder has an option not to add a subexpression as a
187/// block-level expression.
188class AddStmtChoice {
189public:
190 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
191
192 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
193
194 bool alwaysAdd(CFGBuilder &builder,
195 const Stmt *stmt) const;
196
197 /// Return a copy of this object, except with the 'always-add' bit
198 /// set as specified.
199 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
200 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
201 }
202
203private:
204 Kind kind;
205};
206
207/// LocalScope - Node in tree of local scopes created for C++ implicit
208/// destructor calls generation. It contains list of automatic variables
209/// declared in the scope and link to position in previous scope this scope
210/// began in.
211///
212/// The process of creating local scopes is as follows:
213/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
214/// - Before processing statements in scope (e.g. CompoundStmt) create
215/// LocalScope object using CFGBuilder::ScopePos as link to previous scope
216/// and set CFGBuilder::ScopePos to the end of new scope,
217/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
218/// at this VarDecl,
219/// - For every normal (without jump) end of scope add to CFGBlock destructors
220/// for objects in the current scope,
221/// - For every jump add to CFGBlock destructors for objects
222/// between CFGBuilder::ScopePos and local scope position saved for jump
223/// target. Thanks to C++ restrictions on goto jumps we can be sure that
224/// jump target position will be on the path to root from CFGBuilder::ScopePos
225/// (adding any variable that doesn't need constructor to be called to
226/// LocalScope can break this assumption),
227///
228class LocalScope {
229public:
230 using AutomaticVarsTy = BumpVector<VarDecl *>;
231
232 /// const_iterator - Iterates local scope backwards and jumps to previous
233 /// scope on reaching the beginning of currently iterated scope.
234 class const_iterator {
235 const LocalScope* Scope = nullptr;
236
237 /// VarIter is guaranteed to be greater then 0 for every valid iterator.
238 /// Invalid iterator (with null Scope) has VarIter equal to 0.
239 unsigned VarIter = 0;
240
241 public:
242 /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
243 /// Incrementing invalid iterator is allowed and will result in invalid
244 /// iterator.
245 const_iterator() = default;
246
247 /// Create valid iterator. In case when S.Prev is an invalid iterator and
248 /// I is equal to 0, this will create invalid iterator.
249 const_iterator(const LocalScope& S, unsigned I)
250 : Scope(&S), VarIter(I) {
251 // Iterator to "end" of scope is not allowed. Handle it by going up
252 // in scopes tree possibly up to invalid iterator in the root.
253 if (VarIter == 0 && Scope)
254 *this = Scope->Prev;
255 }
256
257 VarDecl *const* operator->() const {
258 assert(Scope && "Dereferencing invalid iterator is not allowed");
259 assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
260 return &Scope->Vars[VarIter - 1];
261 }
262
263 const VarDecl *getFirstVarInScope() const {
264 assert(Scope && "Dereferencing invalid iterator is not allowed");
265 assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
266 return Scope->Vars[0];
267 }
268
269 VarDecl *operator*() const {
270 return *this->operator->();
271 }
272
273 const_iterator &operator++() {
274 if (!Scope)
275 return *this;
276
277 assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
278 --VarIter;
279 if (VarIter == 0)
280 *this = Scope->Prev;
281 return *this;
282 }
283 const_iterator operator++(int) {
284 const_iterator P = *this;
285 ++*this;
286 return P;
287 }
288
289 bool operator==(const const_iterator &rhs) const {
290 return Scope == rhs.Scope && VarIter == rhs.VarIter;
291 }
292 bool operator!=(const const_iterator &rhs) const {
293 return !(*this == rhs);
294 }
295
296 explicit operator bool() const {
297 return *this != const_iterator();
298 }
299
300 int distance(const_iterator L);
301 const_iterator shared_parent(const_iterator L);
302 bool pointsToFirstDeclaredVar() { return VarIter == 1; }
303 bool inSameLocalScope(const_iterator rhs) { return Scope == rhs.Scope; }
304 };
305
306private:
308
309 /// Automatic variables in order of declaration.
310 AutomaticVarsTy Vars;
311
312 /// Iterator to variable in previous scope that was declared just before
313 /// begin of this scope.
314 const_iterator Prev;
315
316public:
317 /// Constructs empty scope linked to previous scope in specified place.
318 LocalScope(BumpVectorContext ctx, const_iterator P)
319 : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
320
321 /// Begin of scope in direction of CFG building (backwards).
322 const_iterator begin() const { return const_iterator(*this, Vars.size()); }
323
324 void addVar(VarDecl *VD) {
325 Vars.push_back(VD, ctx);
326 }
327};
328
329} // namespace
330
331/// distance - Calculates distance from this to L. L must be reachable from this
332/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
333/// number of scopes between this and L.
334int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
335 int D = 0;
336 const_iterator F = *this;
337 while (F.Scope != L.Scope) {
338 assert(F != const_iterator() &&
339 "L iterator is not reachable from F iterator.");
340 D += F.VarIter;
341 F = F.Scope->Prev;
342 }
343 D += F.VarIter - L.VarIter;
344 return D;
345}
346
347/// Calculates the closest parent of this iterator
348/// that is in a scope reachable through the parents of L.
349/// I.e. when using 'goto' from this to L, the lifetime of all variables
350/// between this and shared_parent(L) end.
351LocalScope::const_iterator
352LocalScope::const_iterator::shared_parent(LocalScope::const_iterator L) {
353 // one of iterators is not valid (we are not in scope), so common
354 // parent is const_iterator() (i.e. sentinel).
355 if ((*this == const_iterator()) || (L == const_iterator())) {
356 return const_iterator();
357 }
358
359 const_iterator F = *this;
360 if (F.inSameLocalScope(L)) {
361 // Iterators are in the same scope, get common subset of variables.
362 F.VarIter = std::min(F.VarIter, L.VarIter);
363 return F;
364 }
365
366 llvm::SmallDenseMap<const LocalScope *, unsigned, 4> ScopesOfL;
367 while (true) {
368 ScopesOfL.try_emplace(L.Scope, L.VarIter);
369 if (L == const_iterator())
370 break;
371 L = L.Scope->Prev;
372 }
373
374 while (true) {
375 if (auto LIt = ScopesOfL.find(F.Scope); LIt != ScopesOfL.end()) {
376 // Get common subset of variables in given scope
377 F.VarIter = std::min(F.VarIter, LIt->getSecond());
378 return F;
379 }
380 assert(F != const_iterator() &&
381 "L iterator is not reachable from F iterator.");
382 F = F.Scope->Prev;
383 }
384}
385
386namespace {
387
388/// Structure for specifying position in CFG during its build process. It
389/// consists of CFGBlock that specifies position in CFG and
390/// LocalScope::const_iterator that specifies position in LocalScope graph.
391struct BlockScopePosPair {
392 CFGBlock *block = nullptr;
393 LocalScope::const_iterator scopePosition;
394
395 BlockScopePosPair() = default;
396 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
397 : block(b), scopePosition(scopePos) {}
398};
399
400/// TryResult - a class representing a variant over the values
401/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
402/// and is used by the CFGBuilder to decide if a branch condition
403/// can be decided up front during CFG construction.
404class TryResult {
405 int X = -1;
406
407public:
408 TryResult() = default;
409 TryResult(bool b) : X(b ? 1 : 0) {}
410
411 bool isTrue() const { return X == 1; }
412 bool isFalse() const { return X == 0; }
413 bool isKnown() const { return X >= 0; }
414
415 void negate() {
416 assert(isKnown());
417 X ^= 0x1;
418 }
419};
420
421} // namespace
422
423static TryResult bothKnownTrue(TryResult R1, TryResult R2) {
424 if (!R1.isKnown() || !R2.isKnown())
425 return TryResult();
426 return TryResult(R1.isTrue() && R2.isTrue());
427}
428
429namespace {
430
431class reverse_children {
433 ArrayRef<Stmt *> children;
434
435public:
436 reverse_children(Stmt *S);
437
438 using iterator = ArrayRef<Stmt *>::reverse_iterator;
439
440 iterator begin() const { return children.rbegin(); }
441 iterator end() const { return children.rend(); }
442};
443
444} // namespace
445
446reverse_children::reverse_children(Stmt *S) {
447 if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
448 children = CE->getRawSubExprs();
449 return;
450 }
451 switch (S->getStmtClass()) {
452 // Note: Fill in this switch with more cases we want to optimize.
453 case Stmt::InitListExprClass: {
454 InitListExpr *IE = cast<InitListExpr>(S);
455 children = llvm::ArrayRef(reinterpret_cast<Stmt **>(IE->getInits()),
456 IE->getNumInits());
457 return;
458 }
459 default:
460 break;
461 }
462
463 // Default case for all other statements.
464 llvm::append_range(childrenBuf, S->children());
465
466 // This needs to be done *after* childrenBuf has been populated.
467 children = childrenBuf;
468}
469
470namespace {
471
472/// CFGBuilder - This class implements CFG construction from an AST.
473/// The builder is stateful: an instance of the builder should be used to only
474/// construct a single CFG.
475///
476/// Example usage:
477///
478/// CFGBuilder builder;
479/// std::unique_ptr<CFG> cfg = builder.buildCFG(decl, stmt1);
480///
481/// CFG construction is done via a recursive walk of an AST. We actually parse
482/// the AST in reverse order so that the successor of a basic block is
483/// constructed prior to its predecessor. This allows us to nicely capture
484/// implicit fall-throughs without extra basic blocks.
485class CFGBuilder {
486 using JumpTarget = BlockScopePosPair;
487 using JumpSource = BlockScopePosPair;
488
489 ASTContext *Context;
490 std::unique_ptr<CFG> cfg;
491
492 // Current block.
493 CFGBlock *Block = nullptr;
494
495 // Block after the current block.
496 CFGBlock *Succ = nullptr;
497
498 JumpTarget ContinueJumpTarget;
499 JumpTarget BreakJumpTarget;
500 JumpTarget SEHLeaveJumpTarget;
501 CFGBlock *SwitchTerminatedBlock = nullptr;
502 CFGBlock *DefaultCaseBlock = nullptr;
503
504 // This can point to either a C++ try, an Objective-C @try, or an SEH __try.
505 // try and @try can be mixed and generally work the same.
506 // The frontend forbids mixing SEH __try with either try or @try.
507 // So having one for all three is enough.
508 CFGBlock *TryTerminatedBlock = nullptr;
509
510 // Current position in local scope.
511 LocalScope::const_iterator ScopePos;
512
513 // LabelMap records the mapping from Label expressions to their jump targets.
514 using LabelMapTy = llvm::DenseMap<LabelDecl *, JumpTarget>;
515 LabelMapTy LabelMap;
516
517 // A list of blocks that end with a "goto" that must be backpatched to their
518 // resolved targets upon completion of CFG construction.
519 using BackpatchBlocksTy = std::vector<JumpSource>;
520 BackpatchBlocksTy BackpatchBlocks;
521
522 // A list of labels whose address has been taken (for indirect gotos).
523 using LabelSetTy = llvm::SmallSetVector<LabelDecl *, 8>;
524 LabelSetTy AddressTakenLabels;
525
526 // Information about the currently visited C++ object construction site.
527 // This is set in the construction trigger and read when the constructor
528 // or a function that returns an object by value is being visited.
529 llvm::DenseMap<Expr *, const ConstructionContextLayer *>
530 ConstructionContextMap;
531
532 bool badCFG = false;
533 const CFG::BuildOptions &BuildOpts;
534
535 // State to track for building switch statements.
536 bool switchExclusivelyCovered = false;
537 Expr::EvalResult *switchCond = nullptr;
538
539 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry = nullptr;
540 const Stmt *lastLookup = nullptr;
541
542 // Caches boolean evaluations of expressions to avoid multiple re-evaluations
543 // during construction of branches for chained logical operators.
544 using CachedBoolEvalsTy = llvm::DenseMap<Expr *, TryResult>;
545 CachedBoolEvalsTy CachedBoolEvals;
546
547public:
548 explicit CFGBuilder(ASTContext *astContext,
549 const CFG::BuildOptions &buildOpts)
550 : Context(astContext), cfg(new CFG()), BuildOpts(buildOpts) {}
551
552 // buildCFG - Used by external clients to construct the CFG.
553 std::unique_ptr<CFG> buildCFG(const Decl *D, Stmt *Statement);
554
555 bool alwaysAdd(const Stmt *stmt);
556
557private:
558 // Visitors to walk an AST and construct the CFG.
559 CFGBlock *VisitInitListExpr(InitListExpr *ILE, AddStmtChoice asc);
560 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
561 CFGBlock *VisitAttributedStmt(AttributedStmt *A, AddStmtChoice asc);
562 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
563 CFGBlock *VisitBreakStmt(BreakStmt *B);
564 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
565 CFGBlock *VisitCaseStmt(CaseStmt *C);
566 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
567 CFGBlock *VisitCompoundStmt(CompoundStmt *C, bool ExternallyDestructed);
568 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
569 AddStmtChoice asc);
570 CFGBlock *VisitContinueStmt(ContinueStmt *C);
571 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
572 AddStmtChoice asc);
573 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
574 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
575 CFGBlock *VisitCXXNewExpr(CXXNewExpr *DE, AddStmtChoice asc);
576 CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
577 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
578 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
579 AddStmtChoice asc);
580 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
581 AddStmtChoice asc);
582 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
583 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
584 CFGBlock *VisitCXXTypeidExpr(CXXTypeidExpr *S, AddStmtChoice asc);
585 CFGBlock *VisitDeclStmt(DeclStmt *DS);
586 CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
587 CFGBlock *VisitDefaultStmt(DefaultStmt *D);
588 CFGBlock *VisitDoStmt(DoStmt *D);
589 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E,
590 AddStmtChoice asc, bool ExternallyDestructed);
591 CFGBlock *VisitForStmt(ForStmt *F);
592 CFGBlock *VisitGotoStmt(GotoStmt *G);
593 CFGBlock *VisitGCCAsmStmt(GCCAsmStmt *G, AddStmtChoice asc);
594 CFGBlock *VisitIfStmt(IfStmt *I);
595 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
596 CFGBlock *VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc);
597 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
598 CFGBlock *VisitLabelStmt(LabelStmt *L);
599 CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
600 CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
601 CFGBlock *VisitLogicalOperator(BinaryOperator *B);
602 std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
603 Stmt *Term,
604 CFGBlock *TrueBlock,
605 CFGBlock *FalseBlock);
606 CFGBlock *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
607 AddStmtChoice asc);
608 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
609 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
610 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
611 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
612 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
613 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
614 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
615 CFGBlock *VisitObjCMessageExpr(ObjCMessageExpr *E, AddStmtChoice asc);
616 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
617 CFGBlock *VisitReturnStmt(Stmt *S);
618 CFGBlock *VisitCoroutineSuspendExpr(CoroutineSuspendExpr *S,
619 AddStmtChoice asc);
620 CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
621 CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
622 CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
623 CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
624 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
625 CFGBlock *VisitSwitchStmt(SwitchStmt *S);
626 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
627 AddStmtChoice asc);
628 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
629 CFGBlock *VisitWhileStmt(WhileStmt *W);
630 CFGBlock *VisitArrayInitLoopExpr(ArrayInitLoopExpr *A, AddStmtChoice asc);
631
632 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd,
633 bool ExternallyDestructed = false);
634 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
635 CFGBlock *VisitChildren(Stmt *S);
636 CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
637 CFGBlock *VisitOMPExecutableDirective(OMPExecutableDirective *D,
638 AddStmtChoice asc);
639
640 void maybeAddScopeBeginForVarDecl(CFGBlock *B, const VarDecl *VD,
641 const Stmt *S) {
642 if (ScopePos && (VD == ScopePos.getFirstVarInScope()))
643 appendScopeBegin(B, VD, S);
644 }
645
646 /// When creating the CFG for temporary destructors, we want to mirror the
647 /// branch structure of the corresponding constructor calls.
648 /// Thus, while visiting a statement for temporary destructors, we keep a
649 /// context to keep track of the following information:
650 /// - whether a subexpression is executed unconditionally
651 /// - if a subexpression is executed conditionally, the first
652 /// CXXBindTemporaryExpr we encounter in that subexpression (which
653 /// corresponds to the last temporary destructor we have to call for this
654 /// subexpression) and the CFG block at that point (which will become the
655 /// successor block when inserting the decision point).
656 ///
657 /// That way, we can build the branch structure for temporary destructors as
658 /// follows:
659 /// 1. If a subexpression is executed unconditionally, we add the temporary
660 /// destructor calls to the current block.
661 /// 2. If a subexpression is executed conditionally, when we encounter a
662 /// CXXBindTemporaryExpr:
663 /// a) If it is the first temporary destructor call in the subexpression,
664 /// we remember the CXXBindTemporaryExpr and the current block in the
665 /// TempDtorContext; we start a new block, and insert the temporary
666 /// destructor call.
667 /// b) Otherwise, add the temporary destructor call to the current block.
668 /// 3. When we finished visiting a conditionally executed subexpression,
669 /// and we found at least one temporary constructor during the visitation
670 /// (2.a has executed), we insert a decision block that uses the
671 /// CXXBindTemporaryExpr as terminator, and branches to the current block
672 /// if the CXXBindTemporaryExpr was marked executed, and otherwise
673 /// branches to the stored successor.
674 struct TempDtorContext {
675 TempDtorContext() = default;
676 TempDtorContext(TryResult KnownExecuted)
677 : IsConditional(true), KnownExecuted(KnownExecuted) {}
678
679 /// Returns whether we need to start a new branch for a temporary destructor
680 /// call. This is the case when the temporary destructor is
681 /// conditionally executed, and it is the first one we encounter while
682 /// visiting a subexpression - other temporary destructors at the same level
683 /// will be added to the same block and are executed under the same
684 /// condition.
685 bool needsTempDtorBranch() const {
686 return IsConditional && !TerminatorExpr;
687 }
688
689 /// Remember the successor S of a temporary destructor decision branch for
690 /// the corresponding CXXBindTemporaryExpr E.
691 void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
692 Succ = S;
693 TerminatorExpr = E;
694 }
695
696 const bool IsConditional = false;
697 const TryResult KnownExecuted = true;
698 CFGBlock *Succ = nullptr;
699 CXXBindTemporaryExpr *TerminatorExpr = nullptr;
700 };
701
702 // Visitors to walk an AST and generate destructors of temporaries in
703 // full expression.
704 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool ExternallyDestructed,
705 TempDtorContext &Context);
706 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, bool ExternallyDestructed,
707 TempDtorContext &Context);
708 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
709 bool ExternallyDestructed,
710 TempDtorContext &Context);
711 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
712 CXXBindTemporaryExpr *E, bool ExternallyDestructed, TempDtorContext &Context);
713 CFGBlock *VisitConditionalOperatorForTemporaryDtors(
714 AbstractConditionalOperator *E, bool ExternallyDestructed,
715 TempDtorContext &Context);
716 void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
717 CFGBlock *FalseSucc = nullptr);
718
719 // NYS == Not Yet Supported
720 CFGBlock *NYS() {
721 badCFG = true;
722 return Block;
723 }
724
725 // Remember to apply the construction context based on the current \p Layer
726 // when constructing the CFG element for \p CE.
727 void consumeConstructionContext(const ConstructionContextLayer *Layer,
728 Expr *E);
729
730 // Scan \p Child statement to find constructors in it, while keeping in mind
731 // that its parent statement is providing a partial construction context
732 // described by \p Layer. If a constructor is found, it would be assigned
733 // the context based on the layer. If an additional construction context layer
734 // is found, the function recurses into that.
735 void findConstructionContexts(const ConstructionContextLayer *Layer,
736 Stmt *Child);
737
738 // Scan all arguments of a call expression for a construction context.
739 // These sorts of call expressions don't have a common superclass,
740 // hence strict duck-typing.
741 template <typename CallLikeExpr,
742 typename = std::enable_if_t<
743 std::is_base_of_v<CallExpr, CallLikeExpr> ||
744 std::is_base_of_v<CXXConstructExpr, CallLikeExpr> ||
745 std::is_base_of_v<ObjCMessageExpr, CallLikeExpr>>>
746 void findConstructionContextsForArguments(CallLikeExpr *E) {
747 for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) {
748 Expr *Arg = E->getArg(i);
749 if (Arg->getType()->getAsCXXRecordDecl() && !Arg->isGLValue())
750 findConstructionContexts(
751 ConstructionContextLayer::create(cfg->getBumpVectorContext(),
753 Arg);
754 }
755 }
756
757 // Unset the construction context after consuming it. This is done immediately
758 // after adding the CFGConstructor or CFGCXXRecordTypedCall element, so
759 // there's no need to do this manually in every Visit... function.
760 void cleanupConstructionContext(Expr *E);
761
762 void autoCreateBlock() { if (!Block) Block = createBlock(); }
763 CFGBlock *createBlock(bool add_successor = true);
764 CFGBlock *createNoReturnBlock();
765
766 CFGBlock *addStmt(Stmt *S) {
767 return Visit(S, AddStmtChoice::AlwaysAdd);
768 }
769
770 CFGBlock *addInitializer(CXXCtorInitializer *I);
771 void addLoopExit(const Stmt *LoopStmt);
772 void addAutomaticObjHandling(LocalScope::const_iterator B,
773 LocalScope::const_iterator E, Stmt *S);
774 void addAutomaticObjDestruction(LocalScope::const_iterator B,
775 LocalScope::const_iterator E, Stmt *S);
776 void addScopeExitHandling(LocalScope::const_iterator B,
777 LocalScope::const_iterator E, Stmt *S);
778 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
779 void addScopeChangesHandling(LocalScope::const_iterator SrcPos,
780 LocalScope::const_iterator DstPos,
781 Stmt *S);
782 CFGBlock *createScopeChangesHandlingBlock(LocalScope::const_iterator SrcPos,
783 CFGBlock *SrcBlk,
784 LocalScope::const_iterator DstPost,
785 CFGBlock *DstBlk);
786
787 // Local scopes creation.
788 LocalScope* createOrReuseLocalScope(LocalScope* Scope);
789
790 void addLocalScopeForStmt(Stmt *S);
791 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
792 LocalScope* Scope = nullptr);
793 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
794
795 void addLocalScopeAndDtors(Stmt *S);
796
797 const ConstructionContext *retrieveAndCleanupConstructionContext(Expr *E) {
798 if (!BuildOpts.AddRichCXXConstructors)
799 return nullptr;
800
801 const ConstructionContextLayer *Layer = ConstructionContextMap.lookup(E);
802 if (!Layer)
803 return nullptr;
804
805 cleanupConstructionContext(E);
806 return ConstructionContext::createFromLayers(cfg->getBumpVectorContext(),
807 Layer);
808 }
809
810 // Interface to CFGBlock - adding CFGElements.
811
812 void appendStmt(CFGBlock *B, const Stmt *S) {
813 if (alwaysAdd(S) && cachedEntry)
814 cachedEntry->second = B;
815
816 // All block-level expressions should have already been IgnoreParens()ed.
817 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
818 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
819 }
820
821 void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
822 if (const ConstructionContext *CC =
823 retrieveAndCleanupConstructionContext(CE)) {
824 B->appendConstructor(CE, CC, cfg->getBumpVectorContext());
825 return;
826 }
827
828 // No valid construction context found. Fall back to statement.
829 B->appendStmt(CE, cfg->getBumpVectorContext());
830 }
831
832 void appendCall(CFGBlock *B, CallExpr *CE) {
833 if (alwaysAdd(CE) && cachedEntry)
834 cachedEntry->second = B;
835
836 if (const ConstructionContext *CC =
837 retrieveAndCleanupConstructionContext(CE)) {
838 B->appendCXXRecordTypedCall(CE, CC, cfg->getBumpVectorContext());
839 return;
840 }
841
842 // No valid construction context found. Fall back to statement.
843 B->appendStmt(CE, cfg->getBumpVectorContext());
844 }
845
846 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
847 B->appendInitializer(I, cfg->getBumpVectorContext());
848 }
849
850 void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
851 B->appendNewAllocator(NE, cfg->getBumpVectorContext());
852 }
853
854 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
855 B->appendBaseDtor(BS, cfg->getBumpVectorContext());
856 }
857
858 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
859 B->appendMemberDtor(FD, cfg->getBumpVectorContext());
860 }
861
862 void appendObjCMessage(CFGBlock *B, ObjCMessageExpr *ME) {
863 if (alwaysAdd(ME) && cachedEntry)
864 cachedEntry->second = B;
865
866 if (const ConstructionContext *CC =
867 retrieveAndCleanupConstructionContext(ME)) {
868 B->appendCXXRecordTypedCall(ME, CC, cfg->getBumpVectorContext());
869 return;
870 }
871
872 B->appendStmt(const_cast<ObjCMessageExpr *>(ME),
873 cfg->getBumpVectorContext());
874 }
875
876 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
877 B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
878 }
879
880 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
881 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
882 }
883
884 void appendCleanupFunction(CFGBlock *B, VarDecl *VD) {
885 B->appendCleanupFunction(VD, cfg->getBumpVectorContext());
886 }
887
888 void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
889 B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
890 }
891
892 void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
893 B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
894 }
895
896 void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
897 B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
898 }
899
900 void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
901 B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
902 cfg->getBumpVectorContext());
903 }
904
905 /// Add a reachable successor to a block, with the alternate variant that is
906 /// unreachable.
907 void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
908 B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
909 cfg->getBumpVectorContext());
910 }
911
912 void appendScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
913 if (BuildOpts.AddScopes)
914 B->appendScopeBegin(VD, S, cfg->getBumpVectorContext());
915 }
916
917 void appendScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
918 if (BuildOpts.AddScopes)
919 B->appendScopeEnd(VD, S, cfg->getBumpVectorContext());
920 }
921
922 /// Find a relational comparison with an expression evaluating to a
923 /// boolean and a constant other than 0 and 1.
924 /// e.g. if ((x < y) == 10)
925 TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
926 const Expr *LHSExpr = B->getLHS()->IgnoreParens();
927 const Expr *RHSExpr = B->getRHS()->IgnoreParens();
928
929 const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
930 const Expr *BoolExpr = RHSExpr;
931 bool IntFirst = true;
932 if (!IntLiteral) {
933 IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
934 BoolExpr = LHSExpr;
935 IntFirst = false;
936 }
937
938 if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
939 return TryResult();
940
941 llvm::APInt IntValue = IntLiteral->getValue();
942 if ((IntValue == 1) || (IntValue == 0))
943 return TryResult();
944
945 bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
946 !IntValue.isNegative();
947
948 BinaryOperatorKind Bok = B->getOpcode();
949 if (Bok == BO_GT || Bok == BO_GE) {
950 // Always true for 10 > bool and bool > -1
951 // Always false for -1 > bool and bool > 10
952 return TryResult(IntFirst == IntLarger);
953 } else {
954 // Always true for -1 < bool and bool < 10
955 // Always false for 10 < bool and bool < -1
956 return TryResult(IntFirst != IntLarger);
957 }
958 }
959
960 /// Find an incorrect equality comparison. Either with an expression
961 /// evaluating to a boolean and a constant other than 0 and 1.
962 /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
963 /// true/false e.q. (x & 8) == 4.
964 TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
965 const Expr *LHSExpr = B->getLHS()->IgnoreParens();
966 const Expr *RHSExpr = B->getRHS()->IgnoreParens();
967
968 std::optional<llvm::APInt> IntLiteral1 =
969 getIntegerLiteralSubexpressionValue(LHSExpr);
970 const Expr *BoolExpr = RHSExpr;
971
972 if (!IntLiteral1) {
973 IntLiteral1 = getIntegerLiteralSubexpressionValue(RHSExpr);
974 BoolExpr = LHSExpr;
975 }
976
977 if (!IntLiteral1)
978 return TryResult();
979
980 const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
981 if (BitOp && (BitOp->getOpcode() == BO_And ||
982 BitOp->getOpcode() == BO_Or)) {
983 const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
984 const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
985
986 std::optional<llvm::APInt> IntLiteral2 =
987 getIntegerLiteralSubexpressionValue(LHSExpr2);
988
989 if (!IntLiteral2)
990 IntLiteral2 = getIntegerLiteralSubexpressionValue(RHSExpr2);
991
992 if (!IntLiteral2)
993 return TryResult();
994
995 if ((BitOp->getOpcode() == BO_And &&
996 (*IntLiteral2 & *IntLiteral1) != *IntLiteral1) ||
997 (BitOp->getOpcode() == BO_Or &&
998 (*IntLiteral2 | *IntLiteral1) != *IntLiteral1)) {
999 if (BuildOpts.Observer)
1000 BuildOpts.Observer->compareBitwiseEquality(B,
1001 B->getOpcode() != BO_EQ);
1002 return TryResult(B->getOpcode() != BO_EQ);
1003 }
1004 } else if (BoolExpr->isKnownToHaveBooleanValue()) {
1005 if ((*IntLiteral1 == 1) || (*IntLiteral1 == 0)) {
1006 return TryResult();
1007 }
1008 return TryResult(B->getOpcode() != BO_EQ);
1009 }
1010
1011 return TryResult();
1012 }
1013
1014 // Helper function to get an APInt from an expression. Supports expressions
1015 // which are an IntegerLiteral or a UnaryOperator and returns the value with
1016 // all operations performed on it.
1017 // FIXME: it would be good to unify this function with
1018 // IsIntegerLiteralConstantExpr at some point given the similarity between the
1019 // functions.
1020 std::optional<llvm::APInt>
1021 getIntegerLiteralSubexpressionValue(const Expr *E) {
1022
1023 // If unary.
1024 if (const auto *UnOp = dyn_cast<UnaryOperator>(E->IgnoreParens())) {
1025 // Get the sub expression of the unary expression and get the Integer
1026 // Literal.
1027 const Expr *SubExpr = UnOp->getSubExpr()->IgnoreParens();
1028
1029 if (const auto *IntLiteral = dyn_cast<IntegerLiteral>(SubExpr)) {
1030
1031 llvm::APInt Value = IntLiteral->getValue();
1032
1033 // Perform the operation manually.
1034 switch (UnOp->getOpcode()) {
1035 case UO_Plus:
1036 return Value;
1037 case UO_Minus:
1038 return -Value;
1039 case UO_Not:
1040 return ~Value;
1041 case UO_LNot:
1042 return llvm::APInt(Context->getTypeSize(Context->IntTy), !Value);
1043 default:
1044 assert(false && "Unexpected unary operator!");
1045 return std::nullopt;
1046 }
1047 }
1048 } else if (const auto *IntLiteral =
1049 dyn_cast<IntegerLiteral>(E->IgnoreParens()))
1050 return IntLiteral->getValue();
1051
1052 return std::nullopt;
1053 }
1054
1055 TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
1056 const llvm::APSInt &Value1,
1057 const llvm::APSInt &Value2) {
1058 assert(Value1.isSigned() == Value2.isSigned());
1059 switch (Relation) {
1060 default:
1061 return TryResult();
1062 case BO_EQ:
1063 return TryResult(Value1 == Value2);
1064 case BO_NE:
1065 return TryResult(Value1 != Value2);
1066 case BO_LT:
1067 return TryResult(Value1 < Value2);
1068 case BO_LE:
1069 return TryResult(Value1 <= Value2);
1070 case BO_GT:
1071 return TryResult(Value1 > Value2);
1072 case BO_GE:
1073 return TryResult(Value1 >= Value2);
1074 }
1075 }
1076
1077 /// There are two checks handled by this function:
1078 /// 1. Find a law-of-excluded-middle or law-of-noncontradiction expression
1079 /// e.g. if (x || !x), if (x && !x)
1080 /// 2. Find a pair of comparison expressions with or without parentheses
1081 /// with a shared variable and constants and a logical operator between them
1082 /// that always evaluates to either true or false.
1083 /// e.g. if (x != 3 || x != 4)
1084 TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
1085 assert(B->isLogicalOp());
1086 const Expr *LHSExpr = B->getLHS()->IgnoreParens();
1087 const Expr *RHSExpr = B->getRHS()->IgnoreParens();
1088
1089 auto CheckLogicalOpWithNegatedVariable = [this, B](const Expr *E1,
1090 const Expr *E2) {
1091 if (const auto *Negate = dyn_cast<UnaryOperator>(E1)) {
1092 if (Negate->getOpcode() == UO_LNot &&
1093 Expr::isSameComparisonOperand(Negate->getSubExpr(), E2)) {
1094 bool AlwaysTrue = B->getOpcode() == BO_LOr;
1095 if (BuildOpts.Observer)
1096 BuildOpts.Observer->logicAlwaysTrue(B, AlwaysTrue);
1097 return TryResult(AlwaysTrue);
1098 }
1099 }
1100 return TryResult();
1101 };
1102
1103 TryResult Result = CheckLogicalOpWithNegatedVariable(LHSExpr, RHSExpr);
1104 if (Result.isKnown())
1105 return Result;
1106 Result = CheckLogicalOpWithNegatedVariable(RHSExpr, LHSExpr);
1107 if (Result.isKnown())
1108 return Result;
1109
1110 const auto *LHS = dyn_cast<BinaryOperator>(LHSExpr);
1111 const auto *RHS = dyn_cast<BinaryOperator>(RHSExpr);
1112 if (!LHS || !RHS)
1113 return {};
1114
1115 if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
1116 return {};
1117
1118 const Expr *DeclExpr1;
1119 const Expr *NumExpr1;
1121 std::tie(DeclExpr1, BO1, NumExpr1) = tryNormalizeBinaryOperator(LHS);
1122
1123 if (!DeclExpr1 || !NumExpr1)
1124 return {};
1125
1126 const Expr *DeclExpr2;
1127 const Expr *NumExpr2;
1129 std::tie(DeclExpr2, BO2, NumExpr2) = tryNormalizeBinaryOperator(RHS);
1130
1131 if (!DeclExpr2 || !NumExpr2)
1132 return {};
1133
1134 // Check that it is the same variable on both sides.
1135 if (!Expr::isSameComparisonOperand(DeclExpr1, DeclExpr2))
1136 return {};
1137
1138 // Make sure the user's intent is clear (e.g. they're comparing against two
1139 // int literals, or two things from the same enum)
1140 if (!areExprTypesCompatible(NumExpr1, NumExpr2))
1141 return {};
1142
1143 Expr::EvalResult L1Result, L2Result;
1144 if (!NumExpr1->EvaluateAsInt(L1Result, *Context) ||
1145 !NumExpr2->EvaluateAsInt(L2Result, *Context))
1146 return {};
1147
1148 llvm::APSInt L1 = L1Result.Val.getInt();
1149 llvm::APSInt L2 = L2Result.Val.getInt();
1150
1151 // Can't compare signed with unsigned or with different bit width.
1152 if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1153 return {};
1154
1155 // Values that will be used to determine if result of logical
1156 // operator is always true/false
1157 const llvm::APSInt Values[] = {
1158 // Value less than both Value1 and Value2
1159 llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1160 // L1
1161 L1,
1162 // Value between Value1 and Value2
1163 ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1164 L1.isUnsigned()),
1165 // L2
1166 L2,
1167 // Value greater than both Value1 and Value2
1168 llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1169 };
1170
1171 // Check whether expression is always true/false by evaluating the following
1172 // * variable x is less than the smallest literal.
1173 // * variable x is equal to the smallest literal.
1174 // * Variable x is between smallest and largest literal.
1175 // * Variable x is equal to the largest literal.
1176 // * Variable x is greater than largest literal.
1177 bool AlwaysTrue = true, AlwaysFalse = true;
1178 // Track value of both subexpressions. If either side is always
1179 // true/false, another warning should have already been emitted.
1180 bool LHSAlwaysTrue = true, LHSAlwaysFalse = true;
1181 bool RHSAlwaysTrue = true, RHSAlwaysFalse = true;
1182 for (const llvm::APSInt &Value : Values) {
1183 TryResult Res1, Res2;
1184 Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1185 Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1186
1187 if (!Res1.isKnown() || !Res2.isKnown())
1188 return {};
1189
1190 if (B->getOpcode() == BO_LAnd) {
1191 AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1192 AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1193 } else {
1194 AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1195 AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1196 }
1197
1198 LHSAlwaysTrue &= Res1.isTrue();
1199 LHSAlwaysFalse &= Res1.isFalse();
1200 RHSAlwaysTrue &= Res2.isTrue();
1201 RHSAlwaysFalse &= Res2.isFalse();
1202 }
1203
1204 if (AlwaysTrue || AlwaysFalse) {
1205 if (!LHSAlwaysTrue && !LHSAlwaysFalse && !RHSAlwaysTrue &&
1206 !RHSAlwaysFalse && BuildOpts.Observer)
1207 BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1208 return TryResult(AlwaysTrue);
1209 }
1210 return {};
1211 }
1212
1213 /// A bitwise-or with a non-zero constant always evaluates to true.
1214 TryResult checkIncorrectBitwiseOrOperator(const BinaryOperator *B) {
1215 const Expr *LHSConstant =
1217 const Expr *RHSConstant =
1219
1220 if ((LHSConstant && RHSConstant) || (!LHSConstant && !RHSConstant))
1221 return {};
1222
1223 const Expr *Constant = LHSConstant ? LHSConstant : RHSConstant;
1224
1225 Expr::EvalResult Result;
1226 if (!Constant->EvaluateAsInt(Result, *Context))
1227 return {};
1228
1229 if (Result.Val.getInt() == 0)
1230 return {};
1231
1232 if (BuildOpts.Observer)
1233 BuildOpts.Observer->compareBitwiseOr(B);
1234
1235 return TryResult(true);
1236 }
1237
1238 /// Try and evaluate an expression to an integer constant.
1239 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1240 if (!BuildOpts.PruneTriviallyFalseEdges)
1241 return false;
1242 return !S->isTypeDependent() &&
1243 !S->isValueDependent() &&
1244 S->EvaluateAsRValue(outResult, *Context);
1245 }
1246
1247 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1248 /// if we can evaluate to a known value, otherwise return -1.
1249 TryResult tryEvaluateBool(Expr *S) {
1250 if (!BuildOpts.PruneTriviallyFalseEdges ||
1251 S->isTypeDependent() || S->isValueDependent())
1252 return {};
1253
1254 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1255 if (Bop->isLogicalOp() || Bop->isEqualityOp()) {
1256 // Check the cache first.
1257 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1258 if (I != CachedBoolEvals.end())
1259 return I->second; // already in map;
1260
1261 // Retrieve result at first, or the map might be updated.
1262 TryResult Result = evaluateAsBooleanConditionNoCache(S);
1263 CachedBoolEvals[S] = Result; // update or insert
1264 return Result;
1265 }
1266 else {
1267 switch (Bop->getOpcode()) {
1268 default: break;
1269 // For 'x & 0' and 'x * 0', we can determine that
1270 // the value is always false.
1271 case BO_Mul:
1272 case BO_And: {
1273 // If either operand is zero, we know the value
1274 // must be false.
1275 Expr::EvalResult LHSResult;
1276 if (Bop->getLHS()->EvaluateAsInt(LHSResult, *Context)) {
1277 llvm::APSInt IntVal = LHSResult.Val.getInt();
1278 if (!IntVal.getBoolValue()) {
1279 return TryResult(false);
1280 }
1281 }
1282 Expr::EvalResult RHSResult;
1283 if (Bop->getRHS()->EvaluateAsInt(RHSResult, *Context)) {
1284 llvm::APSInt IntVal = RHSResult.Val.getInt();
1285 if (!IntVal.getBoolValue()) {
1286 return TryResult(false);
1287 }
1288 }
1289 }
1290 break;
1291 }
1292 }
1293 }
1294
1295 return evaluateAsBooleanConditionNoCache(S);
1296 }
1297
1298 /// Evaluate as boolean \param E without using the cache.
1299 TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1300 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1301 if (Bop->isLogicalOp()) {
1302 TryResult LHS = tryEvaluateBool(Bop->getLHS());
1303 if (LHS.isKnown()) {
1304 // We were able to evaluate the LHS, see if we can get away with not
1305 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1306 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1307 return LHS.isTrue();
1308
1309 TryResult RHS = tryEvaluateBool(Bop->getRHS());
1310 if (RHS.isKnown()) {
1311 if (Bop->getOpcode() == BO_LOr)
1312 return LHS.isTrue() || RHS.isTrue();
1313 else
1314 return LHS.isTrue() && RHS.isTrue();
1315 }
1316 } else {
1317 TryResult RHS = tryEvaluateBool(Bop->getRHS());
1318 if (RHS.isKnown()) {
1319 // We can't evaluate the LHS; however, sometimes the result
1320 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1321 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1322 return RHS.isTrue();
1323 } else {
1324 TryResult BopRes = checkIncorrectLogicOperator(Bop);
1325 if (BopRes.isKnown())
1326 return BopRes.isTrue();
1327 }
1328 }
1329
1330 return {};
1331 } else if (Bop->isEqualityOp()) {
1332 TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1333 if (BopRes.isKnown())
1334 return BopRes.isTrue();
1335 } else if (Bop->isRelationalOp()) {
1336 TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1337 if (BopRes.isKnown())
1338 return BopRes.isTrue();
1339 } else if (Bop->getOpcode() == BO_Or) {
1340 TryResult BopRes = checkIncorrectBitwiseOrOperator(Bop);
1341 if (BopRes.isKnown())
1342 return BopRes.isTrue();
1343 }
1344 }
1345
1346 bool Result;
1347 if (E->EvaluateAsBooleanCondition(Result, *Context))
1348 return Result;
1349
1350 return {};
1351 }
1352
1353 bool hasTrivialDestructor(const VarDecl *VD) const;
1354 bool needsAutomaticDestruction(const VarDecl *VD) const;
1355};
1356
1357} // namespace
1358
1359Expr *
1361 if (!AILE)
1362 return nullptr;
1363
1364 Expr *AILEInit = AILE->getSubExpr();
1365 while (const auto *E = dyn_cast<ArrayInitLoopExpr>(AILEInit))
1366 AILEInit = E->getSubExpr();
1367
1368 return AILEInit;
1369}
1370
1371inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1372 const Stmt *stmt) const {
1373 return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1374}
1375
1376bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1377 bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1378
1379 if (!BuildOpts.forcedBlkExprs)
1380 return shouldAdd;
1381
1382 if (lastLookup == stmt) {
1383 if (cachedEntry) {
1384 assert(cachedEntry->first == stmt);
1385 return true;
1386 }
1387 return shouldAdd;
1388 }
1389
1390 lastLookup = stmt;
1391
1392 // Perform the lookup!
1394
1395 if (!fb) {
1396 // No need to update 'cachedEntry', since it will always be null.
1397 assert(!cachedEntry);
1398 return shouldAdd;
1399 }
1400
1401 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1402 if (itr == fb->end()) {
1403 cachedEntry = nullptr;
1404 return shouldAdd;
1405 }
1406
1407 cachedEntry = &*itr;
1408 return true;
1409}
1410
1411// FIXME: Add support for dependent-sized array types in C++?
1412// Does it even make sense to build a CFG for an uninstantiated template?
1413static const VariableArrayType *FindVA(const Type *t) {
1414 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1415 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1416 if (vat->getSizeExpr())
1417 return vat;
1418
1419 t = vt->getElementType().getTypePtr();
1420 }
1421
1422 return nullptr;
1423}
1424
1425void CFGBuilder::consumeConstructionContext(
1426 const ConstructionContextLayer *Layer, Expr *E) {
1427 assert((isa<CXXConstructExpr>(E) || isa<CallExpr>(E) ||
1428 isa<ObjCMessageExpr>(E)) && "Expression cannot construct an object!");
1429 if (const ConstructionContextLayer *PreviouslyStoredLayer =
1430 ConstructionContextMap.lookup(E)) {
1431 (void)PreviouslyStoredLayer;
1432 // We might have visited this child when we were finding construction
1433 // contexts within its parents.
1434 assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1435 "Already within a different construction context!");
1436 } else {
1437 ConstructionContextMap[E] = Layer;
1438 }
1439}
1440
1441void CFGBuilder::findConstructionContexts(
1442 const ConstructionContextLayer *Layer, Stmt *Child) {
1443 if (!BuildOpts.AddRichCXXConstructors)
1444 return;
1445
1446 if (!Child)
1447 return;
1448
1449 auto withExtraLayer = [this, Layer](const ConstructionContextItem &Item) {
1450 return ConstructionContextLayer::create(cfg->getBumpVectorContext(), Item,
1451 Layer);
1452 };
1453
1454 switch(Child->getStmtClass()) {
1455 case Stmt::CXXConstructExprClass:
1456 case Stmt::CXXTemporaryObjectExprClass: {
1457 // Support pre-C++17 copy elision AST.
1458 auto *CE = cast<CXXConstructExpr>(Child);
1459 if (BuildOpts.MarkElidedCXXConstructors && CE->isElidable()) {
1460 findConstructionContexts(withExtraLayer(CE), CE->getArg(0));
1461 }
1462
1463 consumeConstructionContext(Layer, CE);
1464 break;
1465 }
1466 // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1467 // FIXME: An isa<> would look much better but this whole switch is a
1468 // workaround for an internal compiler error in MSVC 2015 (see r326021).
1469 case Stmt::CallExprClass:
1470 case Stmt::CXXMemberCallExprClass:
1471 case Stmt::CXXOperatorCallExprClass:
1472 case Stmt::UserDefinedLiteralClass:
1473 case Stmt::ObjCMessageExprClass: {
1474 auto *E = cast<Expr>(Child);
1476 consumeConstructionContext(Layer, E);
1477 break;
1478 }
1479 case Stmt::ExprWithCleanupsClass: {
1480 auto *Cleanups = cast<ExprWithCleanups>(Child);
1481 findConstructionContexts(Layer, Cleanups->getSubExpr());
1482 break;
1483 }
1484 case Stmt::CXXFunctionalCastExprClass: {
1485 auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1486 findConstructionContexts(Layer, Cast->getSubExpr());
1487 break;
1488 }
1489 case Stmt::ImplicitCastExprClass: {
1490 auto *Cast = cast<ImplicitCastExpr>(Child);
1491 // Should we support other implicit cast kinds?
1492 switch (Cast->getCastKind()) {
1493 case CK_NoOp:
1494 case CK_ConstructorConversion:
1495 findConstructionContexts(Layer, Cast->getSubExpr());
1496 break;
1497 default:
1498 break;
1499 }
1500 break;
1501 }
1502 case Stmt::CXXBindTemporaryExprClass: {
1503 auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1504 findConstructionContexts(withExtraLayer(BTE), BTE->getSubExpr());
1505 break;
1506 }
1507 case Stmt::MaterializeTemporaryExprClass: {
1508 // Normally we don't want to search in MaterializeTemporaryExpr because
1509 // it indicates the beginning of a temporary object construction context,
1510 // so it shouldn't be found in the middle. However, if it is the beginning
1511 // of an elidable copy or move construction context, we need to include it.
1512 if (Layer->getItem().getKind() ==
1514 auto *MTE = cast<MaterializeTemporaryExpr>(Child);
1515 findConstructionContexts(withExtraLayer(MTE), MTE->getSubExpr());
1516 }
1517 break;
1518 }
1519 case Stmt::ConditionalOperatorClass: {
1520 auto *CO = cast<ConditionalOperator>(Child);
1521 if (Layer->getItem().getKind() !=
1523 // If the object returned by the conditional operator is not going to be a
1524 // temporary object that needs to be immediately materialized, then
1525 // it must be C++17 with its mandatory copy elision. Do not yet promise
1526 // to support this case.
1527 assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1528 Context->getLangOpts().CPlusPlus17);
1529 break;
1530 }
1531 findConstructionContexts(Layer, CO->getLHS());
1532 findConstructionContexts(Layer, CO->getRHS());
1533 break;
1534 }
1535 case Stmt::InitListExprClass: {
1536 auto *ILE = cast<InitListExpr>(Child);
1537 if (ILE->isTransparent()) {
1538 findConstructionContexts(Layer, ILE->getInit(0));
1539 break;
1540 }
1541 // TODO: Handle other cases. For now, fail to find construction contexts.
1542 break;
1543 }
1544 case Stmt::ParenExprClass: {
1545 // If expression is placed into parenthesis we should propagate the parent
1546 // construction context to subexpressions.
1547 auto *PE = cast<ParenExpr>(Child);
1548 findConstructionContexts(Layer, PE->getSubExpr());
1549 break;
1550 }
1551 default:
1552 break;
1553 }
1554}
1555
1556void CFGBuilder::cleanupConstructionContext(Expr *E) {
1557 assert(BuildOpts.AddRichCXXConstructors &&
1558 "We should not be managing construction contexts!");
1559 assert(ConstructionContextMap.count(E) &&
1560 "Cannot exit construction context without the context!");
1561 ConstructionContextMap.erase(E);
1562}
1563
1564/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1565/// arbitrary statement. Examples include a single expression or a function
1566/// body (compound statement). The ownership of the returned CFG is
1567/// transferred to the caller. If CFG construction fails, this method returns
1568/// NULL.
1569std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1570 assert(cfg.get());
1571 if (!Statement)
1572 return nullptr;
1573
1574 // Create an empty block that will serve as the exit block for the CFG. Since
1575 // this is the first block added to the CFG, it will be implicitly registered
1576 // as the exit block.
1577 Succ = createBlock();
1578 assert(Succ == &cfg->getExit());
1579 Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1580
1581 if (BuildOpts.AddImplicitDtors)
1582 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1583 addImplicitDtorsForDestructor(DD);
1584
1585 // Visit the statements and create the CFG.
1586 CFGBlock *B = addStmt(Statement);
1587
1588 if (badCFG)
1589 return nullptr;
1590
1591 // For C++ constructor add initializers to CFG. Constructors of virtual bases
1592 // are ignored unless the object is of the most derived class.
1593 // class VBase { VBase() = default; VBase(int) {} };
1594 // class A : virtual public VBase { A() : VBase(0) {} };
1595 // class B : public A {};
1596 // B b; // Constructor calls in order: VBase(), A(), B().
1597 // // VBase(0) is ignored because A isn't the most derived class.
1598 // This may result in the virtual base(s) being already initialized at this
1599 // point, in which case we should jump right onto non-virtual bases and
1600 // fields. To handle this, make a CFG branch. We only need to add one such
1601 // branch per constructor, since the Standard states that all virtual bases
1602 // shall be initialized before non-virtual bases and direct data members.
1603 if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1604 CFGBlock *VBaseSucc = nullptr;
1605 for (auto *I : llvm::reverse(CD->inits())) {
1606 if (BuildOpts.AddVirtualBaseBranches && !VBaseSucc &&
1607 I->isBaseInitializer() && I->isBaseVirtual()) {
1608 // We've reached the first virtual base init while iterating in reverse
1609 // order. Make a new block for virtual base initializers so that we
1610 // could skip them.
1611 VBaseSucc = Succ = B ? B : &cfg->getExit();
1612 Block = createBlock();
1613 }
1614 B = addInitializer(I);
1615 if (badCFG)
1616 return nullptr;
1617 }
1618 if (VBaseSucc) {
1619 // Make a branch block for potentially skipping virtual base initializers.
1620 Succ = VBaseSucc;
1621 B = createBlock();
1622 B->setTerminator(
1624 addSuccessor(B, Block, true);
1625 }
1626 }
1627
1628 if (B)
1629 Succ = B;
1630
1631 // Backpatch the gotos whose label -> block mappings we didn't know when we
1632 // encountered them.
1633 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1634 E = BackpatchBlocks.end(); I != E; ++I ) {
1635
1636 CFGBlock *B = I->block;
1637 if (auto *G = dyn_cast<GotoStmt>(B->getTerminator())) {
1638 LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1639 // If there is no target for the goto, then we are looking at an
1640 // incomplete AST. Handle this by not registering a successor.
1641 if (LI == LabelMap.end())
1642 continue;
1643 JumpTarget JT = LI->second;
1644
1645 CFGBlock *SuccBlk = createScopeChangesHandlingBlock(
1646 I->scopePosition, B, JT.scopePosition, JT.block);
1647 addSuccessor(B, SuccBlk);
1648 } else if (auto *G = dyn_cast<GCCAsmStmt>(B->getTerminator())) {
1649 CFGBlock *Successor = (I+1)->block;
1650 for (auto *L : G->labels()) {
1651 LabelMapTy::iterator LI = LabelMap.find(L->getLabel());
1652 // If there is no target for the goto, then we are looking at an
1653 // incomplete AST. Handle this by not registering a successor.
1654 if (LI == LabelMap.end())
1655 continue;
1656 JumpTarget JT = LI->second;
1657 // Successor has been added, so skip it.
1658 if (JT.block == Successor)
1659 continue;
1660 addSuccessor(B, JT.block);
1661 }
1662 I++;
1663 }
1664 }
1665
1666 // Add successors to the Indirect Goto Dispatch block (if we have one).
1667 if (CFGBlock *B = cfg->getIndirectGotoBlock())
1668 for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1669 E = AddressTakenLabels.end(); I != E; ++I ) {
1670 // Lookup the target block.
1671 LabelMapTy::iterator LI = LabelMap.find(*I);
1672
1673 // If there is no target block that contains label, then we are looking
1674 // at an incomplete AST. Handle this by not registering a successor.
1675 if (LI == LabelMap.end()) continue;
1676
1677 addSuccessor(B, LI->second.block);
1678 }
1679
1680 // Create an empty entry block that has no predecessors.
1681 cfg->setEntry(createBlock());
1682
1683 if (BuildOpts.AddRichCXXConstructors)
1684 assert(ConstructionContextMap.empty() &&
1685 "Not all construction contexts were cleaned up!");
1686
1687 return std::move(cfg);
1688}
1689
1690/// createBlock - Used to lazily create blocks that are connected
1691/// to the current (global) successor.
1692CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1693 CFGBlock *B = cfg->createBlock();
1694 if (add_successor && Succ)
1695 addSuccessor(B, Succ);
1696 return B;
1697}
1698
1699/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1700/// CFG. It is *not* connected to the current (global) successor, and instead
1701/// directly tied to the exit block in order to be reachable.
1702CFGBlock *CFGBuilder::createNoReturnBlock() {
1703 CFGBlock *B = createBlock(false);
1705 addSuccessor(B, &cfg->getExit(), Succ);
1706 return B;
1707}
1708
1709/// addInitializer - Add C++ base or member initializer element to CFG.
1710CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1711 if (!BuildOpts.AddInitializers)
1712 return Block;
1713
1714 bool HasTemporaries = false;
1715
1716 // Destructors of temporaries in initialization expression should be called
1717 // after initialization finishes.
1718 Expr *Init = I->getInit();
1719 if (Init) {
1720 HasTemporaries = isa<ExprWithCleanups>(Init);
1721
1722 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1723 // Generate destructors for temporaries in initialization expression.
1724 TempDtorContext Context;
1725 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1726 /*ExternallyDestructed=*/false, Context);
1727 }
1728 }
1729
1730 autoCreateBlock();
1731 appendInitializer(Block, I);
1732
1733 if (Init) {
1734 // If the initializer is an ArrayInitLoopExpr, we want to extract the
1735 // initializer, that's used for each element.
1737 dyn_cast<ArrayInitLoopExpr>(Init));
1738
1739 findConstructionContexts(
1740 ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1741 AILEInit ? AILEInit : Init);
1742
1743 if (HasTemporaries) {
1744 // For expression with temporaries go directly to subexpression to omit
1745 // generating destructors for the second time.
1746 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1747 }
1748 if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1749 if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1750 // In general, appending the expression wrapped by a CXXDefaultInitExpr
1751 // may cause the same Expr to appear more than once in the CFG. Doing it
1752 // here is safe because there's only one initializer per field.
1753 autoCreateBlock();
1754 appendStmt(Block, Default);
1755 if (Stmt *Child = Default->getExpr())
1756 if (CFGBlock *R = Visit(Child))
1757 Block = R;
1758 return Block;
1759 }
1760 }
1761 return Visit(Init);
1762 }
1763
1764 return Block;
1765}
1766
1767/// Retrieve the type of the temporary object whose lifetime was
1768/// extended by a local reference with the given initializer.
1770 bool *FoundMTE = nullptr) {
1771 while (true) {
1772 // Skip parentheses.
1773 Init = Init->IgnoreParens();
1774
1775 // Skip through cleanups.
1776 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1777 Init = EWC->getSubExpr();
1778 continue;
1779 }
1780
1781 // Skip through the temporary-materialization expression.
1782 if (const MaterializeTemporaryExpr *MTE
1783 = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1784 Init = MTE->getSubExpr();
1785 if (FoundMTE)
1786 *FoundMTE = true;
1787 continue;
1788 }
1789
1790 // Skip sub-object accesses into rvalues.
1791 const Expr *SkippedInit = Init->skipRValueSubobjectAdjustments();
1792 if (SkippedInit != Init) {
1793 Init = SkippedInit;
1794 continue;
1795 }
1796
1797 break;
1798 }
1799
1800 return Init->getType();
1801}
1802
1803// TODO: Support adding LoopExit element to the CFG in case where the loop is
1804// ended by ReturnStmt, GotoStmt or ThrowExpr.
1805void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1806 if(!BuildOpts.AddLoopExit)
1807 return;
1808 autoCreateBlock();
1809 appendLoopExit(Block, LoopStmt);
1810}
1811
1812/// Adds the CFG elements for leaving the scope of automatic objects in
1813/// range [B, E). This include following:
1814/// * AutomaticObjectDtor for variables with non-trivial destructor
1815/// * LifetimeEnds for all variables
1816/// * ScopeEnd for each scope left
1817void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1818 LocalScope::const_iterator E,
1819 Stmt *S) {
1820 if (!BuildOpts.AddScopes && !BuildOpts.AddImplicitDtors &&
1821 !BuildOpts.AddLifetime)
1822 return;
1823
1824 if (B == E)
1825 return;
1826
1827 // Not leaving the scope, only need to handle destruction and lifetime
1828 if (B.inSameLocalScope(E)) {
1829 addAutomaticObjDestruction(B, E, S);
1830 return;
1831 }
1832
1833 // Extract information about all local scopes that are left
1835 LocalScopeEndMarkers.push_back(B);
1836 for (LocalScope::const_iterator I = B; I != E; ++I) {
1837 if (!I.inSameLocalScope(LocalScopeEndMarkers.back()))
1838 LocalScopeEndMarkers.push_back(I);
1839 }
1840 LocalScopeEndMarkers.push_back(E);
1841
1842 // We need to leave the scope in reverse order, so we reverse the end
1843 // markers
1844 std::reverse(LocalScopeEndMarkers.begin(), LocalScopeEndMarkers.end());
1845 auto Pairwise =
1846 llvm::zip(LocalScopeEndMarkers, llvm::drop_begin(LocalScopeEndMarkers));
1847 for (auto [E, B] : Pairwise) {
1848 if (!B.inSameLocalScope(E))
1849 addScopeExitHandling(B, E, S);
1850 addAutomaticObjDestruction(B, E, S);
1851 }
1852}
1853
1854/// Add CFG elements corresponding to call destructor and end of lifetime
1855/// of all automatic variables with non-trivial destructor in range [B, E).
1856/// This include AutomaticObjectDtor and LifetimeEnds elements.
1857void CFGBuilder::addAutomaticObjDestruction(LocalScope::const_iterator B,
1858 LocalScope::const_iterator E,
1859 Stmt *S) {
1860 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime)
1861 return;
1862
1863 if (B == E)
1864 return;
1865
1866 SmallVector<VarDecl *, 10> DeclsNeedDestruction;
1867 DeclsNeedDestruction.reserve(B.distance(E));
1868
1869 for (VarDecl* D : llvm::make_range(B, E))
1870 if (needsAutomaticDestruction(D))
1871 DeclsNeedDestruction.push_back(D);
1872
1873 for (VarDecl *VD : llvm::reverse(DeclsNeedDestruction)) {
1874 if (BuildOpts.AddImplicitDtors) {
1875 // If this destructor is marked as a no-return destructor, we need to
1876 // create a new block for the destructor which does not have as a
1877 // successor anything built thus far: control won't flow out of this
1878 // block.
1879 QualType Ty = VD->getType();
1880 if (Ty->isReferenceType())
1882 Ty = Context->getBaseElementType(Ty);
1883
1884 const CXXRecordDecl *CRD = Ty->getAsCXXRecordDecl();
1885 if (CRD && CRD->isAnyDestructorNoReturn())
1886 Block = createNoReturnBlock();
1887 }
1888
1889 autoCreateBlock();
1890
1891 // Add LifetimeEnd after automatic obj with non-trivial destructors,
1892 // as they end their lifetime when the destructor returns. For trivial
1893 // objects, we end lifetime with scope end.
1894 if (BuildOpts.AddLifetime)
1895 appendLifetimeEnds(Block, VD, S);
1896 if (BuildOpts.AddImplicitDtors && !hasTrivialDestructor(VD))
1897 appendAutomaticObjDtor(Block, VD, S);
1898 if (VD->hasAttr<CleanupAttr>())
1899 appendCleanupFunction(Block, VD);
1900 }
1901}
1902
1903/// Add CFG elements corresponding to leaving a scope.
1904/// Assumes that range [B, E) corresponds to single scope.
1905/// This add following elements:
1906/// * LifetimeEnds for all variables with non-trivial destructor
1907/// * ScopeEnd for each scope left
1908void CFGBuilder::addScopeExitHandling(LocalScope::const_iterator B,
1909 LocalScope::const_iterator E, Stmt *S) {
1910 assert(!B.inSameLocalScope(E));
1911 if (!BuildOpts.AddLifetime && !BuildOpts.AddScopes)
1912 return;
1913
1914 if (BuildOpts.AddScopes) {
1915 autoCreateBlock();
1916 appendScopeEnd(Block, B.getFirstVarInScope(), S);
1917 }
1918
1919 if (!BuildOpts.AddLifetime)
1920 return;
1921
1922 // We need to perform the scope leaving in reverse order
1923 SmallVector<VarDecl *, 10> DeclsTrivial;
1924 DeclsTrivial.reserve(B.distance(E));
1925
1926 // Objects with trivial destructor ends their lifetime when their storage
1927 // is destroyed, for automatic variables, this happens when the end of the
1928 // scope is added.
1929 for (VarDecl* D : llvm::make_range(B, E))
1930 if (!needsAutomaticDestruction(D))
1931 DeclsTrivial.push_back(D);
1932
1933 if (DeclsTrivial.empty())
1934 return;
1935
1936 autoCreateBlock();
1937 for (VarDecl *VD : llvm::reverse(DeclsTrivial))
1938 appendLifetimeEnds(Block, VD, S);
1939}
1940
1941/// addScopeChangesHandling - appends information about destruction, lifetime
1942/// and cfgScopeEnd for variables in the scope that was left by the jump, and
1943/// appends cfgScopeBegin for all scopes that where entered.
1944/// We insert the cfgScopeBegin at the end of the jump node, as depending on
1945/// the sourceBlock, each goto, may enter different amount of scopes.
1946void CFGBuilder::addScopeChangesHandling(LocalScope::const_iterator SrcPos,
1947 LocalScope::const_iterator DstPos,
1948 Stmt *S) {
1949 assert(Block && "Source block should be always crated");
1950 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1951 !BuildOpts.AddScopes) {
1952 return;
1953 }
1954
1955 if (SrcPos == DstPos)
1956 return;
1957
1958 // Get common scope, the jump leaves all scopes [SrcPos, BasePos), and
1959 // enter all scopes between [DstPos, BasePos)
1960 LocalScope::const_iterator BasePos = SrcPos.shared_parent(DstPos);
1961
1962 // Append scope begins for scopes entered by goto
1963 if (BuildOpts.AddScopes && !DstPos.inSameLocalScope(BasePos)) {
1964 for (LocalScope::const_iterator I = DstPos; I != BasePos; ++I)
1965 if (I.pointsToFirstDeclaredVar())
1966 appendScopeBegin(Block, *I, S);
1967 }
1968
1969 // Append scopeEnds, destructor and lifetime with the terminator for
1970 // block left by goto.
1971 addAutomaticObjHandling(SrcPos, BasePos, S);
1972}
1973
1974/// createScopeChangesHandlingBlock - Creates a block with cfgElements
1975/// corresponding to changing the scope from the source scope of the GotoStmt,
1976/// to destination scope. Add destructor, lifetime and cfgScopeEnd
1977/// CFGElements to newly created CFGBlock, that will have the CFG terminator
1978/// transferred.
1979CFGBlock *CFGBuilder::createScopeChangesHandlingBlock(
1980 LocalScope::const_iterator SrcPos, CFGBlock *SrcBlk,
1981 LocalScope::const_iterator DstPos, CFGBlock *DstBlk) {
1982 if (SrcPos == DstPos)
1983 return DstBlk;
1984
1985 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1986 (!BuildOpts.AddScopes || SrcPos.inSameLocalScope(DstPos)))
1987 return DstBlk;
1988
1989 // We will update CFBBuilder when creating new block, restore the
1990 // previous state at exit.
1991 SaveAndRestore save_Block(Block), save_Succ(Succ);
1992
1993 // Create a new block, and transfer terminator
1994 Block = createBlock(false);
1995 Block->setTerminator(SrcBlk->getTerminator());
1996 SrcBlk->setTerminator(CFGTerminator());
1997 addSuccessor(Block, DstBlk);
1998
1999 // Fill the created Block with the required elements.
2000 addScopeChangesHandling(SrcPos, DstPos, Block->getTerminatorStmt());
2001
2002 assert(Block && "There should be at least one scope changing Block");
2003 return Block;
2004}
2005
2006/// addImplicitDtorsForDestructor - Add implicit destructors generated for
2007/// base and member objects in destructor.
2008void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
2009 assert(BuildOpts.AddImplicitDtors &&
2010 "Can be called only when dtors should be added");
2011 const CXXRecordDecl *RD = DD->getParent();
2012
2013 // At the end destroy virtual base objects.
2014 for (const auto &VI : RD->vbases()) {
2015 // TODO: Add a VirtualBaseBranch to see if the most derived class
2016 // (which is different from the current class) is responsible for
2017 // destroying them.
2018 const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
2019 if (CD && !CD->hasTrivialDestructor()) {
2020 autoCreateBlock();
2021 appendBaseDtor(Block, &VI);
2022 }
2023 }
2024
2025 // Before virtual bases destroy direct base objects.
2026 for (const auto &BI : RD->bases()) {
2027 if (!BI.isVirtual()) {
2028 const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
2029 if (CD && !CD->hasTrivialDestructor()) {
2030 autoCreateBlock();
2031 appendBaseDtor(Block, &BI);
2032 }
2033 }
2034 }
2035
2036 // First destroy member objects.
2037 for (auto *FI : RD->fields()) {
2038 // Check for constant size array. Set type to array element type.
2039 QualType QT = FI->getType();
2040 // It may be a multidimensional array.
2041 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
2042 if (AT->isZeroSize())
2043 break;
2044 QT = AT->getElementType();
2045 }
2046
2047 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
2048 if (!CD->hasTrivialDestructor()) {
2049 autoCreateBlock();
2050 appendMemberDtor(Block, FI);
2051 }
2052 }
2053}
2054
2055/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
2056/// way return valid LocalScope object.
2057LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
2058 if (Scope)
2059 return Scope;
2060 llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
2061 return new (alloc) LocalScope(BumpVectorContext(alloc), ScopePos);
2062}
2063
2064/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
2065/// that should create implicit scope (e.g. if/else substatements).
2066void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
2067 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
2068 !BuildOpts.AddScopes)
2069 return;
2070
2071 LocalScope *Scope = nullptr;
2072
2073 // For compound statement we will be creating explicit scope.
2074 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
2075 for (auto *BI : CS->body()) {
2076 Stmt *SI = BI->stripLabelLikeStatements();
2077 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
2078 Scope = addLocalScopeForDeclStmt(DS, Scope);
2079 }
2080 return;
2081 }
2082
2083 // For any other statement scope will be implicit and as such will be
2084 // interesting only for DeclStmt.
2085 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
2086 addLocalScopeForDeclStmt(DS);
2087}
2088
2089/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
2090/// reuse Scope if not NULL.
2091LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
2092 LocalScope* Scope) {
2093 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
2094 !BuildOpts.AddScopes)
2095 return Scope;
2096
2097 for (auto *DI : DS->decls())
2098 if (VarDecl *VD = dyn_cast<VarDecl>(DI))
2099 Scope = addLocalScopeForVarDecl(VD, Scope);
2100 return Scope;
2101}
2102
2103bool CFGBuilder::needsAutomaticDestruction(const VarDecl *VD) const {
2104 return !hasTrivialDestructor(VD) || VD->hasAttr<CleanupAttr>();
2105}
2106
2107bool CFGBuilder::hasTrivialDestructor(const VarDecl *VD) const {
2108 // Check for const references bound to temporary. Set type to pointee.
2109 QualType QT = VD->getType();
2110 if (QT->isReferenceType()) {
2111 // Attempt to determine whether this declaration lifetime-extends a
2112 // temporary.
2113 //
2114 // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
2115 // temporaries, and a single declaration can extend multiple temporaries.
2116 // We should look at the storage duration on each nested
2117 // MaterializeTemporaryExpr instead.
2118
2119 const Expr *Init = VD->getInit();
2120 if (!Init) {
2121 // Probably an exception catch-by-reference variable.
2122 // FIXME: It doesn't really mean that the object has a trivial destructor.
2123 // Also are there other cases?
2124 return true;
2125 }
2126
2127 // Lifetime-extending a temporary?
2128 bool FoundMTE = false;
2129 QT = getReferenceInitTemporaryType(Init, &FoundMTE);
2130 if (!FoundMTE)
2131 return true;
2132 }
2133
2134 // Check for constant size array. Set type to array element type.
2135 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
2136 if (AT->isZeroSize())
2137 return true;
2138 QT = AT->getElementType();
2139 }
2140
2141 // Check if type is a C++ class with non-trivial destructor.
2142 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
2143 return !CD->hasDefinition() || CD->hasTrivialDestructor();
2144 return true;
2145}
2146
2147/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
2148/// create add scope for automatic objects and temporary objects bound to
2149/// const reference. Will reuse Scope if not NULL.
2150LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
2151 LocalScope* Scope) {
2152 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
2153 !BuildOpts.AddScopes)
2154 return Scope;
2155
2156 // Check if variable is local.
2157 if (!VD->hasLocalStorage())
2158 return Scope;
2159
2160 if (!BuildOpts.AddLifetime && !BuildOpts.AddScopes &&
2161 !needsAutomaticDestruction(VD)) {
2162 assert(BuildOpts.AddImplicitDtors);
2163 return Scope;
2164 }
2165
2166 // Add the variable to scope
2167 Scope = createOrReuseLocalScope(Scope);
2168 Scope->addVar(VD);
2169 ScopePos = Scope->begin();
2170 return Scope;
2171}
2172
2173/// addLocalScopeAndDtors - For given statement add local scope for it and
2174/// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
2175void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
2176 LocalScope::const_iterator scopeBeginPos = ScopePos;
2177 addLocalScopeForStmt(S);
2178 addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
2179}
2180
2181/// Visit - Walk the subtree of a statement and add extra
2182/// blocks for ternary operators, &&, and ||. We also process "," and
2183/// DeclStmts (which may contain nested control-flow).
2184CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc,
2185 bool ExternallyDestructed) {
2186 if (!S) {
2187 badCFG = true;
2188 return nullptr;
2189 }
2190
2191 if (Expr *E = dyn_cast<Expr>(S))
2192 S = E->IgnoreParens();
2193
2194 if (Context->getLangOpts().OpenMP)
2195 if (auto *D = dyn_cast<OMPExecutableDirective>(S))
2196 return VisitOMPExecutableDirective(D, asc);
2197
2198 switch (S->getStmtClass()) {
2199 default:
2200 return VisitStmt(S, asc);
2201
2202 case Stmt::ImplicitValueInitExprClass:
2203 if (BuildOpts.OmitImplicitValueInitializers)
2204 return Block;
2205 return VisitStmt(S, asc);
2206
2207 case Stmt::InitListExprClass:
2208 return VisitInitListExpr(cast<InitListExpr>(S), asc);
2209
2210 case Stmt::AttributedStmtClass:
2211 return VisitAttributedStmt(cast<AttributedStmt>(S), asc);
2212
2213 case Stmt::AddrLabelExprClass:
2214 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
2215
2216 case Stmt::BinaryConditionalOperatorClass:
2217 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
2218
2219 case Stmt::BinaryOperatorClass:
2220 return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
2221
2222 case Stmt::BlockExprClass:
2223 return VisitBlockExpr(cast<BlockExpr>(S), asc);
2224
2225 case Stmt::BreakStmtClass:
2226 return VisitBreakStmt(cast<BreakStmt>(S));
2227
2228 case Stmt::CallExprClass:
2229 case Stmt::CXXOperatorCallExprClass:
2230 case Stmt::CXXMemberCallExprClass:
2231 case Stmt::UserDefinedLiteralClass:
2232 return VisitCallExpr(cast<CallExpr>(S), asc);
2233
2234 case Stmt::CaseStmtClass:
2235 return VisitCaseStmt(cast<CaseStmt>(S));
2236
2237 case Stmt::ChooseExprClass:
2238 return VisitChooseExpr(cast<ChooseExpr>(S), asc);
2239
2240 case Stmt::CompoundStmtClass:
2241 return VisitCompoundStmt(cast<CompoundStmt>(S), ExternallyDestructed);
2242
2243 case Stmt::ConditionalOperatorClass:
2244 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
2245
2246 case Stmt::ContinueStmtClass:
2247 return VisitContinueStmt(cast<ContinueStmt>(S));
2248
2249 case Stmt::CXXCatchStmtClass:
2250 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
2251
2252 case Stmt::ExprWithCleanupsClass:
2253 return VisitExprWithCleanups(cast<ExprWithCleanups>(S),
2254 asc, ExternallyDestructed);
2255
2256 case Stmt::CXXDefaultArgExprClass:
2257 case Stmt::CXXDefaultInitExprClass:
2258 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
2259 // called function's declaration, not by the caller. If we simply add
2260 // this expression to the CFG, we could end up with the same Expr
2261 // appearing multiple times (PR13385).
2262 //
2263 // It's likewise possible for multiple CXXDefaultInitExprs for the same
2264 // expression to be used in the same function (through aggregate
2265 // initialization).
2266 return VisitStmt(S, asc);
2267
2268 case Stmt::CXXBindTemporaryExprClass:
2269 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2270
2271 case Stmt::CXXConstructExprClass:
2272 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2273
2274 case Stmt::CXXNewExprClass:
2275 return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2276
2277 case Stmt::CXXDeleteExprClass:
2278 return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2279
2280 case Stmt::CXXFunctionalCastExprClass:
2281 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2282
2283 case Stmt::CXXTemporaryObjectExprClass:
2284 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2285
2286 case Stmt::CXXThrowExprClass:
2287 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2288
2289 case Stmt::CXXTryStmtClass:
2290 return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2291
2292 case Stmt::CXXTypeidExprClass:
2293 return VisitCXXTypeidExpr(cast<CXXTypeidExpr>(S), asc);
2294
2295 case Stmt::CXXForRangeStmtClass:
2296 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2297
2298 case Stmt::DeclStmtClass:
2299 return VisitDeclStmt(cast<DeclStmt>(S));
2300
2301 case Stmt::DefaultStmtClass:
2302 return VisitDefaultStmt(cast<DefaultStmt>(S));
2303
2304 case Stmt::DoStmtClass:
2305 return VisitDoStmt(cast<DoStmt>(S));
2306
2307 case Stmt::ForStmtClass:
2308 return VisitForStmt(cast<ForStmt>(S));
2309
2310 case Stmt::GotoStmtClass:
2311 return VisitGotoStmt(cast<GotoStmt>(S));
2312
2313 case Stmt::GCCAsmStmtClass:
2314 return VisitGCCAsmStmt(cast<GCCAsmStmt>(S), asc);
2315
2316 case Stmt::IfStmtClass:
2317 return VisitIfStmt(cast<IfStmt>(S));
2318
2319 case Stmt::ImplicitCastExprClass:
2320 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2321
2322 case Stmt::ConstantExprClass:
2323 return VisitConstantExpr(cast<ConstantExpr>(S), asc);
2324
2325 case Stmt::IndirectGotoStmtClass:
2326 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2327
2328 case Stmt::LabelStmtClass:
2329 return VisitLabelStmt(cast<LabelStmt>(S));
2330
2331 case Stmt::LambdaExprClass:
2332 return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2333
2334 case Stmt::MaterializeTemporaryExprClass:
2335 return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2336 asc);
2337
2338 case Stmt::MemberExprClass:
2339 return VisitMemberExpr(cast<MemberExpr>(S), asc);
2340
2341 case Stmt::NullStmtClass:
2342 return Block;
2343
2344 case Stmt::ObjCAtCatchStmtClass:
2345 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2346
2347 case Stmt::ObjCAutoreleasePoolStmtClass:
2348 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2349
2350 case Stmt::ObjCAtSynchronizedStmtClass:
2351 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2352
2353 case Stmt::ObjCAtThrowStmtClass:
2354 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2355
2356 case Stmt::ObjCAtTryStmtClass:
2357 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2358
2359 case Stmt::ObjCForCollectionStmtClass:
2360 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2361
2362 case Stmt::ObjCMessageExprClass:
2363 return VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), asc);
2364
2365 case Stmt::OpaqueValueExprClass:
2366 return Block;
2367
2368 case Stmt::PseudoObjectExprClass:
2369 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2370
2371 case Stmt::ReturnStmtClass:
2372 case Stmt::CoreturnStmtClass:
2373 return VisitReturnStmt(S);
2374
2375 case Stmt::CoyieldExprClass:
2376 case Stmt::CoawaitExprClass:
2377 return VisitCoroutineSuspendExpr(cast<CoroutineSuspendExpr>(S), asc);
2378
2379 case Stmt::SEHExceptStmtClass:
2380 return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2381
2382 case Stmt::SEHFinallyStmtClass:
2383 return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2384
2385 case Stmt::SEHLeaveStmtClass:
2386 return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2387
2388 case Stmt::SEHTryStmtClass:
2389 return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2390
2391 case Stmt::UnaryExprOrTypeTraitExprClass:
2392 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2393 asc);
2394
2395 case Stmt::StmtExprClass:
2396 return VisitStmtExpr(cast<StmtExpr>(S), asc);
2397
2398 case Stmt::SwitchStmtClass:
2399 return VisitSwitchStmt(cast<SwitchStmt>(S));
2400
2401 case Stmt::UnaryOperatorClass:
2402 return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2403
2404 case Stmt::WhileStmtClass:
2405 return VisitWhileStmt(cast<WhileStmt>(S));
2406
2407 case Stmt::ArrayInitLoopExprClass:
2408 return VisitArrayInitLoopExpr(cast<ArrayInitLoopExpr>(S), asc);
2409 }
2410}
2411
2412CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2413 if (asc.alwaysAdd(*this, S)) {
2414 autoCreateBlock();
2415 appendStmt(Block, S);
2416 }
2417
2418 return VisitChildren(S);
2419}
2420
2421/// VisitChildren - Visit the children of a Stmt.
2422CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2423 CFGBlock *B = Block;
2424
2425 // Visit the children in their reverse order so that they appear in
2426 // left-to-right (natural) order in the CFG.
2427 reverse_children RChildren(S);
2428 for (Stmt *Child : RChildren) {
2429 if (Child)
2430 if (CFGBlock *R = Visit(Child))
2431 B = R;
2432 }
2433 return B;
2434}
2435
2436CFGBlock *CFGBuilder::VisitInitListExpr(InitListExpr *ILE, AddStmtChoice asc) {
2437 if (asc.alwaysAdd(*this, ILE)) {
2438 autoCreateBlock();
2439 appendStmt(Block, ILE);
2440 }
2441 CFGBlock *B = Block;
2442
2443 reverse_children RChildren(ILE);
2444 for (Stmt *Child : RChildren) {
2445 if (!Child)
2446 continue;
2447 if (CFGBlock *R = Visit(Child))
2448 B = R;
2449 if (BuildOpts.AddCXXDefaultInitExprInAggregates) {
2450 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Child))
2451 if (Stmt *Child = DIE->getExpr())
2452 if (CFGBlock *R = Visit(Child))
2453 B = R;
2454 }
2455 }
2456 return B;
2457}
2458
2459CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2460 AddStmtChoice asc) {
2461 AddressTakenLabels.insert(A->getLabel());
2462
2463 if (asc.alwaysAdd(*this, A)) {
2464 autoCreateBlock();
2465 appendStmt(Block, A);
2466 }
2467
2468 return Block;
2469}
2470
2472 bool isFallthrough = hasSpecificAttr<FallThroughAttr>(A->getAttrs());
2473 assert((!isFallthrough || isa<NullStmt>(A->getSubStmt())) &&
2474 "expected fallthrough not to have children");
2475 return isFallthrough;
2476}
2477
2478CFGBlock *CFGBuilder::VisitAttributedStmt(AttributedStmt *A,
2479 AddStmtChoice asc) {
2480 // AttributedStmts for [[likely]] can have arbitrary statements as children,
2481 // and the current visitation order here would add the AttributedStmts
2482 // for [[likely]] after the child nodes, which is undesirable: For example,
2483 // if the child contains an unconditional return, the [[likely]] would be
2484 // considered unreachable.
2485 // So only add the AttributedStmt for FallThrough, which has CFG effects and
2486 // also no children, and omit the others. None of the other current StmtAttrs
2487 // have semantic meaning for the CFG.
2488 if (isFallthroughStatement(A) && asc.alwaysAdd(*this, A)) {
2489 autoCreateBlock();
2490 appendStmt(Block, A);
2491 }
2492
2493 return VisitChildren(A);
2494}
2495
2496CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc) {
2497 if (asc.alwaysAdd(*this, U)) {
2498 autoCreateBlock();
2499 appendStmt(Block, U);
2500 }
2501
2502 if (U->getOpcode() == UO_LNot)
2503 tryEvaluateBool(U->getSubExpr()->IgnoreParens());
2504
2505 return Visit(U->getSubExpr(), AddStmtChoice());
2506}
2507
2508CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2509 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2510 appendStmt(ConfluenceBlock, B);
2511
2512 if (badCFG)
2513 return nullptr;
2514
2515 return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2516 ConfluenceBlock).first;
2517}
2518
2519std::pair<CFGBlock*, CFGBlock*>
2520CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2521 Stmt *Term,
2522 CFGBlock *TrueBlock,
2523 CFGBlock *FalseBlock) {
2524 // Introspect the RHS. If it is a nested logical operation, we recursively
2525 // build the CFG using this function. Otherwise, resort to default
2526 // CFG construction behavior.
2527 Expr *RHS = B->getRHS()->IgnoreParens();
2528 CFGBlock *RHSBlock, *ExitBlock;
2529
2530 do {
2531 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2532 if (B_RHS->isLogicalOp()) {
2533 std::tie(RHSBlock, ExitBlock) =
2534 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2535 break;
2536 }
2537
2538 // The RHS is not a nested logical operation. Don't push the terminator
2539 // down further, but instead visit RHS and construct the respective
2540 // pieces of the CFG, and link up the RHSBlock with the terminator
2541 // we have been provided.
2542 ExitBlock = RHSBlock = createBlock(false);
2543
2544 // Even though KnownVal is only used in the else branch of the next
2545 // conditional, tryEvaluateBool performs additional checking on the
2546 // Expr, so it should be called unconditionally.
2547 TryResult KnownVal = tryEvaluateBool(RHS);
2548 if (!KnownVal.isKnown())
2549 KnownVal = tryEvaluateBool(B);
2550
2551 if (!Term) {
2552 assert(TrueBlock == FalseBlock);
2553 addSuccessor(RHSBlock, TrueBlock);
2554 }
2555 else {
2556 RHSBlock->setTerminator(Term);
2557 addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2558 addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2559 }
2560
2561 Block = RHSBlock;
2562 RHSBlock = addStmt(RHS);
2563 }
2564 while (false);
2565
2566 if (badCFG)
2567 return std::make_pair(nullptr, nullptr);
2568
2569 // Generate the blocks for evaluating the LHS.
2570 Expr *LHS = B->getLHS()->IgnoreParens();
2571
2572 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2573 if (B_LHS->isLogicalOp()) {
2574 if (B->getOpcode() == BO_LOr)
2575 FalseBlock = RHSBlock;
2576 else
2577 TrueBlock = RHSBlock;
2578
2579 // For the LHS, treat 'B' as the terminator that we want to sink
2580 // into the nested branch. The RHS always gets the top-most
2581 // terminator.
2582 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2583 }
2584
2585 // Create the block evaluating the LHS.
2586 // This contains the '&&' or '||' as the terminator.
2587 CFGBlock *LHSBlock = createBlock(false);
2588 LHSBlock->setTerminator(B);
2589
2590 Block = LHSBlock;
2591 CFGBlock *EntryLHSBlock = addStmt(LHS);
2592
2593 if (badCFG)
2594 return std::make_pair(nullptr, nullptr);
2595
2596 // See if this is a known constant.
2597 TryResult KnownVal = tryEvaluateBool(LHS);
2598
2599 // Now link the LHSBlock with RHSBlock.
2600 if (B->getOpcode() == BO_LOr) {
2601 addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2602 addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2603 } else {
2604 assert(B->getOpcode() == BO_LAnd);
2605 addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2606 addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2607 }
2608
2609 return std::make_pair(EntryLHSBlock, ExitBlock);
2610}
2611
2612CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2613 AddStmtChoice asc) {
2614 // && or ||
2615 if (B->isLogicalOp())
2616 return VisitLogicalOperator(B);
2617
2618 if (B->getOpcode() == BO_Comma) { // ,
2619 autoCreateBlock();
2620 appendStmt(Block, B);
2621 addStmt(B->getRHS());
2622 return addStmt(B->getLHS());
2623 }
2624
2625 if (B->isAssignmentOp()) {
2626 if (asc.alwaysAdd(*this, B)) {
2627 autoCreateBlock();
2628 appendStmt(Block, B);
2629 }
2630 Visit(B->getLHS());
2631 return Visit(B->getRHS());
2632 }
2633
2634 if (asc.alwaysAdd(*this, B)) {
2635 autoCreateBlock();
2636 appendStmt(Block, B);
2637 }
2638
2639 if (B->isEqualityOp() || B->isRelationalOp())
2640 tryEvaluateBool(B);
2641
2642 CFGBlock *RBlock = Visit(B->getRHS());
2643 CFGBlock *LBlock = Visit(B->getLHS());
2644 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2645 // containing a DoStmt, and the LHS doesn't create a new block, then we should
2646 // return RBlock. Otherwise we'll incorrectly return NULL.
2647 return (LBlock ? LBlock : RBlock);
2648}
2649
2650CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2651 if (asc.alwaysAdd(*this, E)) {
2652 autoCreateBlock();
2653 appendStmt(Block, E);
2654 }
2655 return Block;
2656}
2657
2658CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2659 // "break" is a control-flow statement. Thus we stop processing the current
2660 // block.
2661 if (badCFG)
2662 return nullptr;
2663
2664 // Now create a new block that ends with the break statement.
2665 Block = createBlock(false);
2666 Block->setTerminator(B);
2667
2668 // If there is no target for the break, then we are looking at an incomplete
2669 // AST. This means that the CFG cannot be constructed.
2670 if (BreakJumpTarget.block) {
2671 addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2672 addSuccessor(Block, BreakJumpTarget.block);
2673 } else
2674 badCFG = true;
2675
2676 return Block;
2677}
2678
2679static bool CanThrow(Expr *E, ASTContext &Ctx) {
2680 QualType Ty = E->getType();
2681 if (Ty->isFunctionPointerType() || Ty->isBlockPointerType())
2682 Ty = Ty->getPointeeType();
2683
2684 const FunctionType *FT = Ty->getAs<FunctionType>();
2685 if (FT) {
2686 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2687 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2688 Proto->isNothrow())
2689 return false;
2690 }
2691 return true;
2692}
2693
2694CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2695 // Compute the callee type.
2696 QualType calleeType = C->getCallee()->getType();
2697 if (calleeType == Context->BoundMemberTy) {
2698 QualType boundType = Expr::findBoundMemberType(C->getCallee());
2699
2700 // We should only get a null bound type if processing a dependent
2701 // CFG. Recover by assuming nothing.
2702 if (!boundType.isNull()) calleeType = boundType;
2703 }
2704
2705 // If this is a call to a no-return function, this stops the block here.
2706 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2707
2708 bool AddEHEdge = false;
2709
2710 // Languages without exceptions are assumed to not throw.
2711 if (Context->getLangOpts().Exceptions) {
2712 if (BuildOpts.AddEHEdges)
2713 AddEHEdge = true;
2714 }
2715
2716 // If this is a call to a builtin function, it might not actually evaluate
2717 // its arguments. Don't add them to the CFG if this is the case.
2718 bool OmitArguments = false;
2719
2720 if (FunctionDecl *FD = C->getDirectCallee()) {
2721 // TODO: Support construction contexts for variadic function arguments.
2722 // These are a bit problematic and not very useful because passing
2723 // C++ objects as C-style variadic arguments doesn't work in general
2724 // (see [expr.call]).
2725 if (!FD->isVariadic())
2726 findConstructionContextsForArguments(C);
2727
2728 if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2729 NoReturn = true;
2730 if (FD->hasAttr<NoThrowAttr>())
2731 AddEHEdge = false;
2732 if (FD->getBuiltinID() == Builtin::BI__builtin_object_size ||
2733 FD->getBuiltinID() == Builtin::BI__builtin_dynamic_object_size)
2734 OmitArguments = true;
2735 }
2736
2737 if (!CanThrow(C->getCallee(), *Context))
2738 AddEHEdge = false;
2739
2740 if (OmitArguments) {
2741 assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2742 assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2743 autoCreateBlock();
2744 appendStmt(Block, C);
2745 return Visit(C->getCallee());
2746 }
2747
2748 if (!NoReturn && !AddEHEdge) {
2749 autoCreateBlock();
2750 appendCall(Block, C);
2751
2752 return VisitChildren(C);
2753 }
2754
2755 if (Block) {
2756 Succ = Block;
2757 if (badCFG)
2758 return nullptr;
2759 }
2760
2761 if (NoReturn)
2762 Block = createNoReturnBlock();
2763 else
2764 Block = createBlock();
2765
2766 appendCall(Block, C);
2767
2768 if (AddEHEdge) {
2769 // Add exceptional edges.
2770 if (TryTerminatedBlock)
2771 addSuccessor(Block, TryTerminatedBlock);
2772 else
2773 addSuccessor(Block, &cfg->getExit());
2774 }
2775
2776 return VisitChildren(C);
2777}
2778
2779CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2780 AddStmtChoice asc) {
2781 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2782 appendStmt(ConfluenceBlock, C);
2783 if (badCFG)
2784 return nullptr;
2785
2786 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2787 Succ = ConfluenceBlock;
2788 Block = nullptr;
2789 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2790 if (badCFG)
2791 return nullptr;
2792
2793 Succ = ConfluenceBlock;
2794 Block = nullptr;
2795 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2796 if (badCFG)
2797 return nullptr;
2798
2799 Block = createBlock(false);
2800 // See if this is a known constant.
2801 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2802 addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2803 addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2805 return addStmt(C->getCond());
2806}
2807
2808CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C,
2809 bool ExternallyDestructed) {
2810 LocalScope::const_iterator scopeBeginPos = ScopePos;
2811 addLocalScopeForStmt(C);
2812
2813 if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2814 // If the body ends with a ReturnStmt, the dtors will be added in
2815 // VisitReturnStmt.
2816 addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2817 }
2818
2819 CFGBlock *LastBlock = Block;
2820
2821 for (Stmt *S : llvm::reverse(C->body())) {
2822 // If we hit a segment of code just containing ';' (NullStmts), we can
2823 // get a null block back. In such cases, just use the LastBlock
2824 CFGBlock *newBlock = Visit(S, AddStmtChoice::AlwaysAdd,
2825 ExternallyDestructed);
2826
2827 if (newBlock)
2828 LastBlock = newBlock;
2829
2830 if (badCFG)
2831 return nullptr;
2832
2833 ExternallyDestructed = false;
2834 }
2835
2836 return LastBlock;
2837}
2838
2839CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2840 AddStmtChoice asc) {
2841 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2842 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2843
2844 // Create the confluence block that will "merge" the results of the ternary
2845 // expression.
2846 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2847 appendStmt(ConfluenceBlock, C);
2848 if (badCFG)
2849 return nullptr;
2850
2851 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2852
2853 // Create a block for the LHS expression if there is an LHS expression. A
2854 // GCC extension allows LHS to be NULL, causing the condition to be the
2855 // value that is returned instead.
2856 // e.g: x ?: y is shorthand for: x ? x : y;
2857 Succ = ConfluenceBlock;
2858 Block = nullptr;
2859 CFGBlock *LHSBlock = nullptr;
2860 const Expr *trueExpr = C->getTrueExpr();
2861 if (trueExpr != opaqueValue) {
2862 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2863 if (badCFG)
2864 return nullptr;
2865 Block = nullptr;
2866 }
2867 else
2868 LHSBlock = ConfluenceBlock;
2869
2870 // Create the block for the RHS expression.
2871 Succ = ConfluenceBlock;
2872 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2873 if (badCFG)
2874 return nullptr;
2875
2876 // If the condition is a logical '&&' or '||', build a more accurate CFG.
2877 if (BinaryOperator *Cond =
2878 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2879 if (Cond->isLogicalOp())
2880 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2881
2882 // Create the block that will contain the condition.
2883 Block = createBlock(false);
2884
2885 // See if this is a known constant.
2886 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2887 addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2888 addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2890 Expr *condExpr = C->getCond();
2891
2892 if (opaqueValue) {
2893 // Run the condition expression if it's not trivially expressed in
2894 // terms of the opaque value (or if there is no opaque value).
2895 if (condExpr != opaqueValue)
2896 addStmt(condExpr);
2897
2898 // Before that, run the common subexpression if there was one.
2899 // At least one of this or the above will be run.
2900 return addStmt(BCO->getCommon());
2901 }
2902
2903 return addStmt(condExpr);
2904}
2905
2906CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2907 // Check if the Decl is for an __label__. If so, elide it from the
2908 // CFG entirely.
2909 if (isa<LabelDecl>(*DS->decl_begin()))
2910 return Block;
2911
2912 // This case also handles static_asserts.
2913 if (DS->isSingleDecl())
2914 return VisitDeclSubExpr(DS);
2915
2916 CFGBlock *B = nullptr;
2917
2918 // Build an individual DeclStmt for each decl.
2920 E = DS->decl_rend();
2921 I != E; ++I) {
2922
2923 // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2924 // automatically freed with the CFG.
2925 DeclGroupRef DG(*I);
2926 Decl *D = *I;
2927 DeclStmt *DSNew = new (Context) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2928 cfg->addSyntheticDeclStmt(DSNew, DS);
2929
2930 // Append the fake DeclStmt to block.
2931 B = VisitDeclSubExpr(DSNew);
2932 }
2933
2934 return B;
2935}
2936
2937/// VisitDeclSubExpr - Utility method to add block-level expressions for
2938/// DeclStmts and initializers in them.
2939CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2940 assert(DS->isSingleDecl() && "Can handle single declarations only.");
2941
2942 if (const auto *TND = dyn_cast<TypedefNameDecl>(DS->getSingleDecl())) {
2943 // If we encounter a VLA, process its size expressions.
2944 const Type *T = TND->getUnderlyingType().getTypePtr();
2945 if (!T->isVariablyModifiedType())
2946 return Block;
2947
2948 autoCreateBlock();
2949 appendStmt(Block, DS);
2950
2951 CFGBlock *LastBlock = Block;
2952 for (const VariableArrayType *VA = FindVA(T); VA != nullptr;
2953 VA = FindVA(VA->getElementType().getTypePtr())) {
2954 if (CFGBlock *NewBlock = addStmt(VA->getSizeExpr()))
2955 LastBlock = NewBlock;
2956 }
2957 return LastBlock;
2958 }
2959
2960 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2961
2962 if (!VD) {
2963 // Of everything that can be declared in a DeclStmt, only VarDecls and the
2964 // exceptions above impact runtime semantics.
2965 return Block;
2966 }
2967
2968 bool HasTemporaries = false;
2969
2970 // Guard static initializers under a branch.
2971 CFGBlock *blockAfterStaticInit = nullptr;
2972
2973 if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2974 // For static variables, we need to create a branch to track
2975 // whether or not they are initialized.
2976 if (Block) {
2977 Succ = Block;
2978 Block = nullptr;
2979 if (badCFG)
2980 return nullptr;
2981 }
2982 blockAfterStaticInit = Succ;
2983 }
2984
2985 // Destructors of temporaries in initialization expression should be called
2986 // after initialization finishes.
2987 Expr *Init = VD->getInit();
2988 if (Init) {
2989 HasTemporaries = isa<ExprWithCleanups>(Init);
2990
2991 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2992 // Generate destructors for temporaries in initialization expression.
2993 TempDtorContext Context;
2994 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2995 /*ExternallyDestructed=*/true, Context);
2996 }
2997 }
2998
2999 // If we bind to a tuple-like type, we iterate over the HoldingVars, and
3000 // create a DeclStmt for each of them.
3001 if (const auto *DD = dyn_cast<DecompositionDecl>(VD)) {
3002 for (auto *BD : llvm::reverse(DD->bindings())) {
3003 if (auto *VD = BD->getHoldingVar()) {
3004 DeclGroupRef DG(VD);
3005 DeclStmt *DSNew =
3006 new (Context) DeclStmt(DG, VD->getLocation(), GetEndLoc(VD));
3007 cfg->addSyntheticDeclStmt(DSNew, DS);
3008 Block = VisitDeclSubExpr(DSNew);
3009 }
3010 }
3011 }
3012
3013 autoCreateBlock();
3014 appendStmt(Block, DS);
3015
3016 // If the initializer is an ArrayInitLoopExpr, we want to extract the
3017 // initializer, that's used for each element.
3018 const auto *AILE = dyn_cast_or_null<ArrayInitLoopExpr>(Init);
3019
3020 findConstructionContexts(
3021 ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3022 AILE ? AILE->getSubExpr() : Init);
3023
3024 // Keep track of the last non-null block, as 'Block' can be nulled out
3025 // if the initializer expression is something like a 'while' in a
3026 // statement-expression.
3027 CFGBlock *LastBlock = Block;
3028
3029 if (Init) {
3030 if (HasTemporaries) {
3031 // For expression with temporaries go directly to subexpression to omit
3032 // generating destructors for the second time.
3033 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
3034 if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
3035 LastBlock = newBlock;
3036 }
3037 else {
3038 if (CFGBlock *newBlock = Visit(Init))
3039 LastBlock = newBlock;
3040 }
3041 }
3042
3043 // If the type of VD is a VLA, then we must process its size expressions.
3044 // FIXME: This does not find the VLA if it is embedded in other types,
3045 // like here: `int (*p_vla)[x];`
3046 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
3047 VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
3048 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
3049 LastBlock = newBlock;
3050 }
3051
3052 maybeAddScopeBeginForVarDecl(Block, VD, DS);
3053
3054 // Remove variable from local scope.
3055 if (ScopePos && VD == *ScopePos)
3056 ++ScopePos;
3057
3058 CFGBlock *B = LastBlock;
3059 if (blockAfterStaticInit) {
3060 Succ = B;
3061 Block = createBlock(false);
3062 Block->setTerminator(DS);
3063 addSuccessor(Block, blockAfterStaticInit);
3064 addSuccessor(Block, B);
3065 B = Block;
3066 }
3067
3068 return B;
3069}
3070
3071CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
3072 // We may see an if statement in the middle of a basic block, or it may be the
3073 // first statement we are processing. In either case, we create a new basic
3074 // block. First, we create the blocks for the then...else statements, and
3075 // then we create the block containing the if statement. If we were in the
3076 // middle of a block, we stop processing that block. That block is then the
3077 // implicit successor for the "then" and "else" clauses.
3078
3079 // Save local scope position because in case of condition variable ScopePos
3080 // won't be restored when traversing AST.
3081 SaveAndRestore save_scope_pos(ScopePos);
3082
3083 // Create local scope for C++17 if init-stmt if one exists.
3084 if (Stmt *Init = I->getInit())
3085 addLocalScopeForStmt(Init);
3086
3087 // Create local scope for possible condition variable.
3088 // Store scope position. Add implicit destructor.
3089 if (VarDecl *VD = I->getConditionVariable())
3090 addLocalScopeForVarDecl(VD);
3091
3092 addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
3093
3094 // The block we were processing is now finished. Make it the successor
3095 // block.
3096 if (Block) {
3097 Succ = Block;
3098 if (badCFG)
3099 return nullptr;
3100 }
3101
3102 // Process the false branch.
3103 CFGBlock *ElseBlock = Succ;
3104
3105 if (Stmt *Else = I->getElse()) {
3106 SaveAndRestore sv(Succ);
3107
3108 // NULL out Block so that the recursive call to Visit will
3109 // create a new basic block.
3110 Block = nullptr;
3111
3112 // If branch is not a compound statement create implicit scope
3113 // and add destructors.
3114 if (!isa<CompoundStmt>(Else))
3115 addLocalScopeAndDtors(Else);
3116
3117 ElseBlock = addStmt(Else);
3118
3119 if (!ElseBlock) // Can occur when the Else body has all NullStmts.
3120 ElseBlock = sv.get();
3121 else if (Block) {
3122 if (badCFG)
3123 return nullptr;
3124 }
3125 }
3126
3127 // Process the true branch.
3128 CFGBlock *ThenBlock;
3129 {
3130 Stmt *Then = I->getThen();
3131 assert(Then);
3132 SaveAndRestore sv(Succ);
3133 Block = nullptr;
3134
3135 // If branch is not a compound statement create implicit scope
3136 // and add destructors.
3137 if (!isa<CompoundStmt>(Then))
3138 addLocalScopeAndDtors(Then);
3139
3140 ThenBlock = addStmt(Then);
3141
3142 if (!ThenBlock) {
3143 // We can reach here if the "then" body has all NullStmts.
3144 // Create an empty block so we can distinguish between true and false
3145 // branches in path-sensitive analyses.
3146 ThenBlock = createBlock(false);
3147 addSuccessor(ThenBlock, sv.get());
3148 } else if (Block) {
3149 if (badCFG)
3150 return nullptr;
3151 }
3152 }
3153
3154 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
3155 // having these handle the actual control-flow jump. Note that
3156 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
3157 // we resort to the old control-flow behavior. This special handling
3158 // removes infeasible paths from the control-flow graph by having the
3159 // control-flow transfer of '&&' or '||' go directly into the then/else
3160 // blocks directly.
3161 BinaryOperator *Cond =
3162 (I->isConsteval() || I->getConditionVariable())
3163 ? nullptr
3164 : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
3165 CFGBlock *LastBlock;
3166 if (Cond && Cond->isLogicalOp())
3167 LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
3168 else {
3169 // Now create a new block containing the if statement.
3170 Block = createBlock(false);
3171
3172 // Set the terminator of the new block to the If statement.
3173 Block->setTerminator(I);
3174
3175 // See if this is a known constant.
3176 TryResult KnownVal;
3177 if (!I->isConsteval())
3178 KnownVal = tryEvaluateBool(I->getCond());
3179
3180 // Add the successors. If we know that specific branches are
3181 // unreachable, inform addSuccessor() of that knowledge.
3182 addSuccessor(Block, ThenBlock, /* IsReachable = */ !KnownVal.isFalse());
3183 addSuccessor(Block, ElseBlock, /* IsReachable = */ !KnownVal.isTrue());
3184
3185 // Add the condition as the last statement in the new block. This may
3186 // create new blocks as the condition may contain control-flow. Any newly
3187 // created blocks will be pointed to be "Block".
3188 LastBlock = addStmt(I->getCond());
3189
3190 // If the IfStmt contains a condition variable, add it and its
3191 // initializer to the CFG.
3192 if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
3193 autoCreateBlock();
3194 LastBlock = addStmt(const_cast<DeclStmt *>(DS));
3195 }
3196 }
3197
3198 // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
3199 if (Stmt *Init = I->getInit()) {
3200 autoCreateBlock();
3201 LastBlock = addStmt(Init);
3202 }
3203
3204 return LastBlock;
3205}
3206
3207CFGBlock *CFGBuilder::VisitReturnStmt(Stmt *S) {
3208 // If we were in the middle of a block we stop processing that block.
3209 //
3210 // NOTE: If a "return" or "co_return" appears in the middle of a block, this
3211 // means that the code afterwards is DEAD (unreachable). We still keep
3212 // a basic block for that code; a simple "mark-and-sweep" from the entry
3213 // block will be able to report such dead blocks.
3214 assert(isa<ReturnStmt>(S) || isa<CoreturnStmt>(S));
3215
3216 // Create the new block.
3217 Block = createBlock(false);
3218
3219 addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), S);
3220
3221 if (auto *R = dyn_cast<ReturnStmt>(S))
3222 findConstructionContexts(
3223 ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
3224 R->getRetValue());
3225
3226 // If the one of the destructors does not return, we already have the Exit
3227 // block as a successor.
3228 if (!Block->hasNoReturnElement())
3229 addSuccessor(Block, &cfg->getExit());
3230
3231 // Add the return statement to the block.
3232 appendStmt(Block, S);
3233
3234 // Visit children
3235 if (ReturnStmt *RS = dyn_cast<ReturnStmt>(S)) {
3236 if (Expr *O = RS->getRetValue())
3237 return Visit(O, AddStmtChoice::AlwaysAdd, /*ExternallyDestructed=*/true);
3238 return Block;
3239 }
3240
3241 CoreturnStmt *CRS = cast<CoreturnStmt>(S);
3242 auto *B = Block;
3243 if (CFGBlock *R = Visit(CRS->getPromiseCall()))
3244 B = R;
3245
3246 if (Expr *RV = CRS->getOperand())
3247 if (RV->getType()->isVoidType() && !isa<InitListExpr>(RV))
3248 // A non-initlist void expression.
3249 if (CFGBlock *R = Visit(RV))
3250 B = R;
3251
3252 return B;
3253}
3254
3255CFGBlock *CFGBuilder::VisitCoroutineSuspendExpr(CoroutineSuspendExpr *E,
3256 AddStmtChoice asc) {
3257 // We're modelling the pre-coro-xform CFG. Thus just evalate the various
3258 // active components of the co_await or co_yield. Note we do not model the
3259 // edge from the builtin_suspend to the exit node.
3260 if (asc.alwaysAdd(*this, E)) {
3261 autoCreateBlock();
3262 appendStmt(Block, E);
3263 }
3264 CFGBlock *B = Block;
3265 if (auto *R = Visit(E->getResumeExpr()))
3266 B = R;
3267 if (auto *R = Visit(E->getSuspendExpr()))
3268 B = R;
3269 if (auto *R = Visit(E->getReadyExpr()))
3270 B = R;
3271 if (auto *R = Visit(E->getCommonExpr()))
3272 B = R;
3273 return B;
3274}
3275
3276CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
3277 // SEHExceptStmt are treated like labels, so they are the first statement in a
3278 // block.
3279
3280 // Save local scope position because in case of exception variable ScopePos
3281 // won't be restored when traversing AST.
3282 SaveAndRestore save_scope_pos(ScopePos);
3283
3284 addStmt(ES->getBlock());
3285 CFGBlock *SEHExceptBlock = Block;
3286 if (!SEHExceptBlock)
3287 SEHExceptBlock = createBlock();
3288
3289 appendStmt(SEHExceptBlock, ES);
3290
3291 // Also add the SEHExceptBlock as a label, like with regular labels.
3292 SEHExceptBlock->setLabel(ES);
3293
3294 // Bail out if the CFG is bad.
3295 if (badCFG)
3296 return nullptr;
3297
3298 // We set Block to NULL to allow lazy creation of a new block (if necessary).
3299 Block = nullptr;
3300
3301 return SEHExceptBlock;
3302}
3303
3304CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
3305 return VisitCompoundStmt(FS->getBlock(), /*ExternallyDestructed=*/false);
3306}
3307
3308CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
3309 // "__leave" is a control-flow statement. Thus we stop processing the current
3310 // block.
3311 if (badCFG)
3312 return nullptr;
3313
3314 // Now create a new block that ends with the __leave statement.
3315 Block = createBlock(false);
3316 Block->setTerminator(LS);
3317
3318 // If there is no target for the __leave, then we are looking at an incomplete
3319 // AST. This means that the CFG cannot be constructed.
3320 if (SEHLeaveJumpTarget.block) {
3321 addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
3322 addSuccessor(Block, SEHLeaveJumpTarget.block);
3323 } else
3324 badCFG = true;
3325
3326 return Block;
3327}
3328
3329CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
3330 // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
3331 // processing the current block.
3332 CFGBlock *SEHTrySuccessor = nullptr;
3333
3334 if (Block) {
3335 if (badCFG)
3336 return nullptr;
3337 SEHTrySuccessor = Block;
3338 } else SEHTrySuccessor = Succ;
3339
3340 // FIXME: Implement __finally support.
3341 if (Terminator->getFinallyHandler())
3342 return NYS();
3343
3344 CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
3345
3346 // Create a new block that will contain the __try statement.
3347 CFGBlock *NewTryTerminatedBlock = createBlock(false);
3348
3349 // Add the terminator in the __try block.
3350 NewTryTerminatedBlock->setTerminator(Terminator);
3351
3352 if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
3353 // The code after the try is the implicit successor if there's an __except.
3354 Succ = SEHTrySuccessor;
3355 Block = nullptr;
3356 CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
3357 if (!ExceptBlock)
3358 return nullptr;
3359 // Add this block to the list of successors for the block with the try
3360 // statement.
3361 addSuccessor(NewTryTerminatedBlock, ExceptBlock);
3362 }
3363 if (PrevSEHTryTerminatedBlock)
3364 addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
3365 else
3366 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3367
3368 // The code after the try is the implicit successor.
3369 Succ = SEHTrySuccessor;
3370
3371 // Save the current "__try" context.
3372 SaveAndRestore SaveTry(TryTerminatedBlock, NewTryTerminatedBlock);
3373 cfg->addTryDispatchBlock(TryTerminatedBlock);
3374
3375 // Save the current value for the __leave target.
3376 // All __leaves should go to the code following the __try
3377 // (FIXME: or if the __try has a __finally, to the __finally.)
3378 SaveAndRestore save_break(SEHLeaveJumpTarget);
3379 SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3380
3381 assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3382 Block = nullptr;
3383 return addStmt(Terminator->getTryBlock());
3384}
3385
3386CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3387 // Get the block of the labeled statement. Add it to our map.
3388 addStmt(L->getSubStmt());
3389 CFGBlock *LabelBlock = Block;
3390
3391 if (!LabelBlock) // This can happen when the body is empty, i.e.
3392 LabelBlock = createBlock(); // scopes that only contains NullStmts.
3393
3394 assert(!LabelMap.contains(L->getDecl()) && "label already in map");
3395 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3396
3397 // Labels partition blocks, so this is the end of the basic block we were
3398 // processing (L is the block's label). Because this is label (and we have
3399 // already processed the substatement) there is no extra control-flow to worry
3400 // about.
3401 LabelBlock->setLabel(L);
3402 if (badCFG)
3403 return nullptr;
3404
3405 // We set Block to NULL to allow lazy creation of a new block (if necessary).
3406 Block = nullptr;
3407
3408 // This block is now the implicit successor of other blocks.
3409 Succ = LabelBlock;
3410
3411 return LabelBlock;
3412}
3413
3414CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3415 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3416 for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3417 if (Expr *CopyExpr = CI.getCopyExpr()) {
3418 CFGBlock *Tmp = Visit(CopyExpr);
3419 if (Tmp)
3420 LastBlock = Tmp;
3421 }
3422 }
3423 return LastBlock;
3424}
3425
3426CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3427 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3428
3429 unsigned Idx = 0;
3431 et = E->capture_init_end();
3432 it != et; ++it, ++Idx) {
3433 if (Expr *Init = *it) {
3434 // If the initializer is an ArrayInitLoopExpr, we want to extract the
3435 // initializer, that's used for each element.
3437 dyn_cast<ArrayInitLoopExpr>(Init));
3438
3439 findConstructionContexts(ConstructionContextLayer::create(
3440 cfg->getBumpVectorContext(), {E, Idx}),
3441 AILEInit ? AILEInit : Init);
3442
3443 CFGBlock *Tmp = Visit(Init);
3444 if (Tmp)
3445 LastBlock = Tmp;
3446 }
3447 }
3448 return LastBlock;
3449}
3450
3451CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3452 // Goto is a control-flow statement. Thus we stop processing the current
3453 // block and create a new one.
3454
3455 Block = createBlock(false);
3456 Block->setTerminator(G);
3457
3458 // If we already know the mapping to the label block add the successor now.
3459 LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3460
3461 if (I == LabelMap.end())
3462 // We will need to backpatch this block later.
3463 BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3464 else {
3465 JumpTarget JT = I->second;
3466 addSuccessor(Block, JT.block);
3467 addScopeChangesHandling(ScopePos, JT.scopePosition, G);
3468 }
3469
3470 return Block;
3471}
3472
3473CFGBlock *CFGBuilder::VisitGCCAsmStmt(GCCAsmStmt *G, AddStmtChoice asc) {
3474 // Goto is a control-flow statement. Thus we stop processing the current
3475 // block and create a new one.
3476
3477 if (!G->isAsmGoto())
3478 return VisitStmt(G, asc);
3479
3480 if (Block) {
3481 Succ = Block;
3482 if (badCFG)
3483 return nullptr;
3484 }
3485 Block = createBlock();
3486 Block->setTerminator(G);
3487 // We will backpatch this block later for all the labels.
3488 BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3489 // Save "Succ" in BackpatchBlocks. In the backpatch processing, "Succ" is
3490 // used to avoid adding "Succ" again.
3491 BackpatchBlocks.push_back(JumpSource(Succ, ScopePos));
3492 return VisitChildren(G);
3493}
3494
3495CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3496 CFGBlock *LoopSuccessor = nullptr;
3497
3498 // Save local scope position because in case of condition variable ScopePos
3499 // won't be restored when traversing AST.
3500 SaveAndRestore save_scope_pos(ScopePos);
3501
3502 // Create local scope for init statement and possible condition variable.
3503 // Add destructor for init statement and condition variable.
3504 // Store scope position for continue statement.
3505 if (Stmt *Init = F->getInit())
3506 addLocalScopeForStmt(Init);
3507 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3508
3509 if (VarDecl *VD = F->getConditionVariable())
3510 addLocalScopeForVarDecl(VD);
3511 LocalScope::const_iterator ContinueScopePos = ScopePos;
3512
3513 addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3514
3515 addLoopExit(F);
3516
3517 // "for" is a control-flow statement. Thus we stop processing the current
3518 // block.
3519 if (Block) {
3520 if (badCFG)
3521 return nullptr;
3522 LoopSuccessor = Block;
3523 } else
3524 LoopSuccessor = Succ;
3525
3526 // Save the current value for the break targets.
3527 // All breaks should go to the code following the loop.
3528 SaveAndRestore save_break(BreakJumpTarget);
3529 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3530
3531 CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3532
3533 // Now create the loop body.
3534 {
3535 assert(F->getBody());
3536
3537 // Save the current values for Block, Succ, continue and break targets.
3538 SaveAndRestore save_Block(Block), save_Succ(Succ);
3539 SaveAndRestore save_continue(ContinueJumpTarget);
3540
3541 // Create an empty block to represent the transition block for looping back
3542 // to the head of the loop. If we have increment code, it will
3543 // go in this block as well.
3544 Block = Succ = TransitionBlock = createBlock(false);
3545 TransitionBlock->setLoopTarget(F);
3546
3547
3548 // Loop iteration (after increment) should end with destructor of Condition
3549 // variable (if any).
3550 addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3551
3552 if (Stmt *I = F->getInc()) {
3553 // Generate increment code in its own basic block. This is the target of
3554 // continue statements.
3555 Succ = addStmt(I);
3556 }
3557
3558 // Finish up the increment (or empty) block if it hasn't been already.
3559 if (Block) {
3560 assert(Block == Succ);
3561 if (badCFG)
3562 return nullptr;
3563 Block = nullptr;
3564 }
3565
3566 // The starting block for the loop increment is the block that should
3567 // represent the 'loop target' for looping back to the start of the loop.
3568 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3569 ContinueJumpTarget.block->setLoopTarget(F);
3570
3571
3572 // If body is not a compound statement create implicit scope
3573 // and add destructors.
3574 if (!isa<CompoundStmt>(F->getBody()))
3575 addLocalScopeAndDtors(F->getBody());
3576
3577 // Now populate the body block, and in the process create new blocks as we
3578 // walk the body of the loop.
3579 BodyBlock = addStmt(F->getBody());
3580
3581 if (!BodyBlock) {
3582 // In the case of "for (...;...;...);" we can have a null BodyBlock.
3583 // Use the continue jump target as the proxy for the body.
3584 BodyBlock = ContinueJumpTarget.block;
3585 }
3586 else if (badCFG)
3587 return nullptr;
3588 }
3589
3590 // Because of short-circuit evaluation, the condition of the loop can span
3591 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3592 // evaluate the condition.
3593 CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3594
3595 do {
3596 Expr *C = F->getCond();
3597 SaveAndRestore save_scope_pos(ScopePos);
3598
3599 // Specially handle logical operators, which have a slightly
3600 // more optimal CFG representation.
3601 if (BinaryOperator *Cond =
3602 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3603 if (Cond->isLogicalOp()) {
3604 std::tie(EntryConditionBlock, ExitConditionBlock) =
3605 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3606 break;
3607 }
3608
3609 // The default case when not handling logical operators.
3610 EntryConditionBlock = ExitConditionBlock = createBlock(false);
3611 ExitConditionBlock->setTerminator(F);
3612
3613 // See if this is a known constant.
3614 TryResult KnownVal(true);
3615
3616 if (C) {
3617 // Now add the actual condition to the condition block.
3618 // Because the condition itself may contain control-flow, new blocks may
3619 // be created. Thus we update "Succ" after adding the condition.
3620 Block = ExitConditionBlock;
3621 EntryConditionBlock = addStmt(C);
3622
3623 // If this block contains a condition variable, add both the condition
3624 // variable and initializer to the CFG.
3625 if (VarDecl *VD = F->getConditionVariable()) {
3626 if (Expr *Init = VD->getInit()) {
3627 autoCreateBlock();
3628 const DeclStmt *DS = F->getConditionVariableDeclStmt();
3629 assert(DS->isSingleDecl());
3630 findConstructionContexts(
3631 ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3632 Init);
3633 appendStmt(Block, DS);
3634 EntryConditionBlock = addStmt(Init);
3635 assert(Block == EntryConditionBlock);
3636 maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3637 }
3638 }
3639
3640 if (Block && badCFG)
3641 return nullptr;
3642
3643 KnownVal = tryEvaluateBool(C);
3644 }
3645
3646 // Add the loop body entry as a successor to the condition.
3647 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3648 // Link up the condition block with the code that follows the loop. (the
3649 // false branch).
3650 addSuccessor(ExitConditionBlock,
3651 KnownVal.isTrue() ? nullptr : LoopSuccessor);
3652 } while (false);
3653
3654 // Link up the loop-back block to the entry condition block.
3655 addSuccessor(TransitionBlock, EntryConditionBlock);
3656
3657 // The condition block is the implicit successor for any code above the loop.
3658 Succ = EntryConditionBlock;
3659
3660 // If the loop contains initialization, create a new block for those
3661 // statements. This block can also contain statements that precede the loop.
3662 if (Stmt *I = F->getInit()) {
3663 SaveAndRestore save_scope_pos(ScopePos);
3664 ScopePos = LoopBeginScopePos;
3665 Block = createBlock();
3666 return addStmt(I);
3667 }
3668
3669 // There is no loop initialization. We are thus basically a while loop.
3670 // NULL out Block to force lazy block construction.
3671 Block = nullptr;
3672 Succ = EntryConditionBlock;
3673 return EntryConditionBlock;
3674}
3675
3676CFGBlock *
3677CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3678 AddStmtChoice asc) {
3679 findConstructionContexts(
3680 ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3681 MTE->getSubExpr());
3682
3683 return VisitStmt(MTE, asc);
3684}
3685
3686CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3687 if (asc.alwaysAdd(*this, M)) {
3688 autoCreateBlock();
3689 appendStmt(Block, M);
3690 }
3691 return Visit(M->getBase());
3692}
3693
3694CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3695 // Objective-C fast enumeration 'for' statements:
3696 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3697 //
3698 // for ( Type newVariable in collection_expression ) { statements }
3699 //
3700 // becomes:
3701 //
3702 // prologue:
3703 // 1. collection_expression
3704 // T. jump to loop_entry
3705 // loop_entry:
3706 // 1. side-effects of element expression
3707 // 1. ObjCForCollectionStmt [performs binding to newVariable]
3708 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3709 // TB:
3710 // statements
3711 // T. jump to loop_entry
3712 // FB:
3713 // what comes after
3714 //
3715 // and
3716 //
3717 // Type existingItem;
3718 // for ( existingItem in expression ) { statements }
3719 //
3720 // becomes:
3721 //
3722 // the same with newVariable replaced with existingItem; the binding works
3723 // the same except that for one ObjCForCollectionStmt::getElement() returns
3724 // a DeclStmt and the other returns a DeclRefExpr.
3725
3726 CFGBlock *LoopSuccessor = nullptr;
3727
3728 if (Block) {
3729 if (badCFG)
3730 return nullptr;
3731 LoopSuccessor = Block;
3732 Block = nullptr;
3733 } else
3734 LoopSuccessor = Succ;
3735
3736 // Build the condition blocks.
3737 CFGBlock *ExitConditionBlock = createBlock(false);
3738
3739 // Set the terminator for the "exit" condition block.
3740 ExitConditionBlock->setTerminator(S);
3741
3742 // The last statement in the block should be the ObjCForCollectionStmt, which
3743 // performs the actual binding to 'element' and determines if there are any
3744 // more items in the collection.
3745 appendStmt(ExitConditionBlock, S);
3746 Block = ExitConditionBlock;
3747
3748 // Walk the 'element' expression to see if there are any side-effects. We
3749 // generate new blocks as necessary. We DON'T add the statement by default to
3750 // the CFG unless it contains control-flow.
3751 CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3752 AddStmtChoice::NotAlwaysAdd);
3753 if (Block) {
3754 if (badCFG)
3755 return nullptr;
3756 Block = nullptr;
3757 }
3758
3759 // The condition block is the implicit successor for the loop body as well as
3760 // any code above the loop.
3761 Succ = EntryConditionBlock;
3762
3763 // Now create the true branch.
3764 {
3765 // Save the current values for Succ, continue and break targets.
3766 SaveAndRestore save_Block(Block), save_Succ(Succ);
3767 SaveAndRestore save_continue(ContinueJumpTarget),
3768 save_break(BreakJumpTarget);
3769
3770 // Add an intermediate block between the BodyBlock and the
3771 // EntryConditionBlock to represent the "loop back" transition, for looping
3772 // back to the head of the loop.
3773 CFGBlock *LoopBackBlock = nullptr;
3774 Succ = LoopBackBlock = createBlock();
3775 LoopBackBlock->setLoopTarget(S);
3776
3777 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3778 ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3779
3780 CFGBlock *BodyBlock = addStmt(S->getBody());
3781
3782 if (!BodyBlock)
3783 BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3784 else if (Block) {
3785 if (badCFG)
3786 return nullptr;
3787 }
3788
3789 // This new body block is a successor to our "exit" condition block.
3790 addSuccessor(ExitConditionBlock, BodyBlock);
3791 }
3792
3793 // Link up the condition block with the code that follows the loop.
3794 // (the false branch).
3795 addSuccessor(ExitConditionBlock, LoopSuccessor);
3796
3797 // Now create a prologue block to contain the collection expression.
3798 Block = createBlock();
3799 return addStmt(S->getCollection());
3800}
3801
3802CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3803 // Inline the body.
3804 return addStmt(S->getSubStmt());
3805 // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3806}
3807
3808CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3809 // FIXME: Add locking 'primitives' to CFG for @synchronized.
3810
3811 // Inline the body.
3812 CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3813
3814 // The sync body starts its own basic block. This makes it a little easier
3815 // for diagnostic clients.
3816 if (SyncBlock) {
3817 if (badCFG)
3818 return nullptr;
3819
3820 Block = nullptr;
3821 Succ = SyncBlock;
3822 }
3823
3824 // Add the @synchronized to the CFG.
3825 autoCreateBlock();
3826 appendStmt(Block, S);
3827
3828 // Inline the sync expression.
3829 return addStmt(S->getSynchExpr());
3830}
3831
3832CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3833 autoCreateBlock();
3834
3835 // Add the PseudoObject as the last thing.
3836 appendStmt(Block, E);
3837
3838 CFGBlock *lastBlock = Block;
3839
3840 // Before that, evaluate all of the semantics in order. In
3841 // CFG-land, that means appending them in reverse order.
3842 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3843 Expr *Semantic = E->getSemanticExpr(--i);
3844
3845 // If the semantic is an opaque value, we're being asked to bind
3846 // it to its source expression.
3847 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3848 Semantic = OVE->getSourceExpr();
3849
3850 if (CFGBlock *B = Visit(Semantic))
3851 lastBlock = B;
3852 }
3853
3854 return lastBlock;
3855}
3856
3857CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3858 CFGBlock *LoopSuccessor = nullptr;
3859
3860 // Save local scope position because in case of condition variable ScopePos
3861 // won't be restored when traversing AST.
3862 SaveAndRestore save_scope_pos(ScopePos);
3863
3864 // Create local scope for possible condition variable.
3865 // Store scope position for continue statement.
3866 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3867 if (VarDecl *VD = W->getConditionVariable()) {
3868 addLocalScopeForVarDecl(VD);
3869 addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3870 }
3871 addLoopExit(W);
3872
3873 // "while" is a control-flow statement. Thus we stop processing the current
3874 // block.
3875 if (Block) {
3876 if (badCFG)
3877 return nullptr;
3878 LoopSuccessor = Block;
3879 Block = nullptr;
3880 } else {
3881 LoopSuccessor = Succ;
3882 }
3883
3884 CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3885
3886 // Process the loop body.
3887 {
3888 assert(W->getBody());
3889
3890 // Save the current values for Block, Succ, continue and break targets.
3891 SaveAndRestore save_Block(Block), save_Succ(Succ);
3892 SaveAndRestore save_continue(ContinueJumpTarget),
3893 save_break(BreakJumpTarget);
3894
3895 // Create an empty block to represent the transition block for looping back
3896 // to the head of the loop.
3897 Succ = TransitionBlock = createBlock(false);
3898 TransitionBlock->setLoopTarget(W);
3899 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3900
3901 // All breaks should go to the code following the loop.
3902 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3903
3904 // Loop body should end with destructor of Condition variable (if any).
3905 addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3906
3907 // If body is not a compound statement create implicit scope
3908 // and add destructors.
3909 if (!isa<CompoundStmt>(W->getBody()))
3910 addLocalScopeAndDtors(W->getBody());
3911
3912 // Create the body. The returned block is the entry to the loop body.
3913 BodyBlock = addStmt(W->getBody());
3914
3915 if (!BodyBlock)
3916 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3917 else if (Block && badCFG)
3918 return nullptr;
3919 }
3920
3921 // Because of short-circuit evaluation, the condition of the loop can span
3922 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3923 // evaluate the condition.
3924 CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3925
3926 do {
3927 Expr *C = W->getCond();
3928
3929 // Specially handle logical operators, which have a slightly
3930 // more optimal CFG representation.
3931 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3932 if (Cond->isLogicalOp()) {
3933 std::tie(EntryConditionBlock, ExitConditionBlock) =
3934 VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3935 break;
3936 }
3937
3938 // The default case when not handling logical operators.
3939 ExitConditionBlock = createBlock(false);
3940 ExitConditionBlock->setTerminator(W);
3941
3942 // Now add the actual condition to the condition block.
3943 // Because the condition itself may contain control-flow, new blocks may
3944 // be created. Thus we update "Succ" after adding the condition.
3945 Block = ExitConditionBlock;
3946 Block = EntryConditionBlock = addStmt(C);
3947
3948 // If this block contains a condition variable, add both the condition
3949 // variable and initializer to the CFG.
3950 if (VarDecl *VD = W->getConditionVariable()) {
3951 if (Expr *Init = VD->getInit()) {
3952 autoCreateBlock();
3953 const DeclStmt *DS = W->getConditionVariableDeclStmt();
3954 assert(DS->isSingleDecl());
3955 findConstructionContexts(
3956 ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3957 const_cast<DeclStmt *>(DS)),
3958 Init);
3959 appendStmt(Block, DS);
3960 EntryConditionBlock = addStmt(Init);
3961 assert(Block == EntryConditionBlock);
3962 maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3963 }
3964 }
3965
3966 if (Block && badCFG)
3967 return nullptr;
3968
3969 // See if this is a known constant.
3970 const TryResult& KnownVal = tryEvaluateBool(C);
3971
3972 // Add the loop body entry as a successor to the condition.
3973 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3974 // Link up the condition block with the code that follows the loop. (the
3975 // false branch).
3976 addSuccessor(ExitConditionBlock,
3977 KnownVal.isTrue() ? nullptr : LoopSuccessor);
3978 } while(false);
3979
3980 // Link up the loop-back block to the entry condition block.
3981 addSuccessor(TransitionBlock, EntryConditionBlock);
3982
3983 // There can be no more statements in the condition block since we loop back
3984 // to this block. NULL out Block to force lazy creation of another block.
3985 Block = nullptr;
3986
3987 // Return the condition block, which is the dominating block for the loop.
3988 Succ = EntryConditionBlock;
3989 return EntryConditionBlock;
3990}
3991
3992CFGBlock *CFGBuilder::VisitArrayInitLoopExpr(ArrayInitLoopExpr *A,
3993 AddStmtChoice asc) {
3994 if (asc.alwaysAdd(*this, A)) {
3995 autoCreateBlock();
3996 appendStmt(Block, A);
3997 }
3998
3999 CFGBlock *B = Block;
4000
4001 if (CFGBlock *R = Visit(A->getSubExpr()))
4002 B = R;
4003
4004 auto *OVE = dyn_cast<OpaqueValueExpr>(A->getCommonExpr());
4005 assert(OVE && "ArrayInitLoopExpr->getCommonExpr() should be wrapped in an "
4006 "OpaqueValueExpr!");
4007 if (CFGBlock *R = Visit(OVE->getSourceExpr()))
4008 B = R;
4009
4010 return B;
4011}
4012
4013CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *CS) {
4014 // ObjCAtCatchStmt are treated like labels, so they are the first statement
4015 // in a block.
4016
4017 // Save local scope position because in case of exception variable ScopePos
4018 // won't be restored when traversing AST.
4019 SaveAndRestore save_scope_pos(ScopePos);
4020
4021 if (CS->getCatchBody())
4022 addStmt(CS->getCatchBody());
4023
4024 CFGBlock *CatchBlock = Block;
4025 if (!CatchBlock)
4026 CatchBlock = createBlock();
4027
4028 appendStmt(CatchBlock, CS);
4029
4030 // Also add the ObjCAtCatchStmt as a label, like with regular labels.
4031 CatchBlock->setLabel(CS);
4032
4033 // Bail out if the CFG is bad.
4034 if (badCFG)
4035 return nullptr;
4036
4037 // We set Block to NULL to allow lazy creation of a new block (if necessary).
4038 Block = nullptr;
4039
4040 return CatchBlock;
4041}
4042
4043CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
4044 // If we were in the middle of a block we stop processing that block.
4045 if (badCFG)
4046 return nullptr;
4047
4048 // Create the new block.
4049 Block = createBlock(false);
4050
4051 if (TryTerminatedBlock)
4052 // The current try statement is the only successor.
4053 addSuccessor(Block, TryTerminatedBlock);
4054 else
4055 // otherwise the Exit block is the only successor.
4056 addSuccessor(Block, &cfg->getExit());
4057
4058 // Add the statement to the block. This may create new blocks if S contains
4059 // control-flow (short-circuit operations).
4060 return VisitStmt(S, AddStmtChoice::AlwaysAdd);
4061}
4062
4063CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *Terminator) {
4064 // "@try"/"@catch" is a control-flow statement. Thus we stop processing the
4065 // current block.
4066 CFGBlock *TrySuccessor = nullptr;
4067
4068 if (Block) {
4069 if (badCFG)
4070 return nullptr;
4071 TrySuccessor = Block;
4072 } else
4073 TrySuccessor = Succ;
4074
4075 // FIXME: Implement @finally support.
4076 if (Terminator->getFinallyStmt())
4077 return NYS();
4078
4079 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4080
4081 // Create a new block that will contain the try statement.
4082 CFGBlock *NewTryTerminatedBlock = createBlock(false);
4083 // Add the terminator in the try block.
4084 NewTryTerminatedBlock->setTerminator(Terminator);
4085
4086 bool HasCatchAll = false;
4087 for (ObjCAtCatchStmt *CS : Terminator->catch_stmts()) {
4088 // The code after the try is the implicit successor.
4089 Succ = TrySuccessor;
4090 if (CS->hasEllipsis()) {
4091 HasCatchAll = true;
4092 }
4093 Block = nullptr;
4094 CFGBlock *CatchBlock = VisitObjCAtCatchStmt(CS);
4095 if (!CatchBlock)
4096 return nullptr;
4097 // Add this block to the list of successors for the block with the try
4098 // statement.
4099 addSuccessor(NewTryTerminatedBlock, CatchBlock);
4100 }
4101
4102 // FIXME: This needs updating when @finally support is added.
4103 if (!HasCatchAll) {
4104 if (PrevTryTerminatedBlock)
4105 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4106 else
4107 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4108 }
4109
4110 // The code after the try is the implicit successor.
4111 Succ = TrySuccessor;
4112
4113 // Save the current "try" context.
4114 SaveAndRestore SaveTry(TryTerminatedBlock, NewTryTerminatedBlock);
4115 cfg->addTryDispatchBlock(TryTerminatedBlock);
4116
4117 assert(Terminator->getTryBody() && "try must contain a non-NULL body");
4118 Block = nullptr;
4119 return addStmt(Terminator->getTryBody());
4120}
4121
4122CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
4123 AddStmtChoice asc) {
4124 findConstructionContextsForArguments(ME);
4125
4126 autoCreateBlock();
4127 appendObjCMessage(Block, ME);
4128
4129 return VisitChildren(ME);
4130}
4131
4132CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
4133 // If we were in the middle of a block we stop processing that block.
4134 if (badCFG)
4135 return nullptr;
4136
4137 // Create the new block.
4138 Block = createBlock(false);
4139
4140 if (TryTerminatedBlock)
4141 // The current try statement is the only successor.
4142 addSuccessor(Block, TryTerminatedBlock);
4143 else
4144 // otherwise the Exit block is the only successor.
4145 addSuccessor(Block, &cfg->getExit());
4146
4147 // Add the statement to the block. This may create new blocks if S contains
4148 // control-flow (short-circuit operations).
4149 return VisitStmt(T, AddStmtChoice::AlwaysAdd);
4150}
4151
4152CFGBlock *CFGBuilder::VisitCXXTypeidExpr(CXXTypeidExpr *S, AddStmtChoice asc) {
4153 if (asc.alwaysAdd(*this, S)) {
4154 autoCreateBlock();
4155 appendStmt(Block, S);
4156 }
4157
4158 // C++ [expr.typeid]p3:
4159 // When typeid is applied to an expression other than an glvalue of a
4160 // polymorphic class type [...] [the] expression is an unevaluated
4161 // operand. [...]
4162 // We add only potentially evaluated statements to the block to avoid
4163 // CFG generation for unevaluated operands.
4164 if (!S->isTypeDependent() && S->isPotentiallyEvaluated())
4165 return VisitChildren(S);
4166
4167 // Return block without CFG for unevaluated operands.
4168 return Block;
4169}
4170
4171CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
4172 CFGBlock *LoopSuccessor = nullptr;
4173
4174 addLoopExit(D);
4175
4176 // "do...while" is a control-flow statement. Thus we stop processing the
4177 // current block.
4178 if (Block) {
4179 if (badCFG)
4180 return nullptr;
4181 LoopSuccessor = Block;
4182 } else
4183 LoopSuccessor = Succ;
4184
4185 // Because of short-circuit evaluation, the condition of the loop can span
4186 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
4187 // evaluate the condition.
4188 CFGBlock *ExitConditionBlock = createBlock(false);
4189 CFGBlock *EntryConditionBlock = ExitConditionBlock;
4190
4191 // Set the terminator for the "exit" condition block.
4192 ExitConditionBlock->setTerminator(D);
4193
4194 // Now add the actual condition to the condition block. Because the condition
4195 // itself may contain control-flow, new blocks may be created.
4196 if (Stmt *C = D->getCond()) {
4197 Block = ExitConditionBlock;
4198 EntryConditionBlock = addStmt(C);
4199 if (Block) {
4200 if (badCFG)
4201 return nullptr;
4202 }
4203 }
4204
4205 // The condition block is the implicit successor for the loop body.
4206 Succ = EntryConditionBlock;
4207
4208 // See if this is a known constant.
4209 const TryResult &KnownVal = tryEvaluateBool(D->getCond());
4210
4211 // Process the loop body.
4212 CFGBlock *BodyBlock = nullptr;
4213 {
4214 assert(D->getBody());
4215
4216 // Save the current values for Block, Succ, and continue and break targets
4217 SaveAndRestore save_Block(Block), save_Succ(Succ);
4218 SaveAndRestore save_continue(ContinueJumpTarget),
4219 save_break(BreakJumpTarget);
4220
4221 // All continues within this loop should go to the condition block
4222 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
4223
4224 // All breaks should go to the code following the loop.
4225 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4226
4227 // NULL out Block to force lazy instantiation of blocks for the body.
4228 Block = nullptr;
4229
4230 // If body is not a compound statement create implicit scope
4231 // and add destructors.
4232 if (!isa<CompoundStmt>(D->getBody()))
4233 addLocalScopeAndDtors(D->getBody());
4234
4235 // Create the body. The returned block is the entry to the loop body.
4236 BodyBlock = addStmt(D->getBody());
4237
4238 if (!BodyBlock)
4239 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
4240 else if (Block) {
4241 if (badCFG)
4242 return nullptr;
4243 }
4244
4245 // Add an intermediate block between the BodyBlock and the
4246 // ExitConditionBlock to represent the "loop back" transition. Create an
4247 // empty block to represent the transition block for looping back to the
4248 // head of the loop.
4249 // FIXME: Can we do this more efficiently without adding another block?
4250 Block = nullptr;
4251 Succ = BodyBlock;
4252 CFGBlock *LoopBackBlock = createBlock();
4253 LoopBackBlock->setLoopTarget(D);
4254
4255 if (!KnownVal.isFalse())
4256 // Add the loop body entry as a successor to the condition.
4257 addSuccessor(ExitConditionBlock, LoopBackBlock);
4258 else
4259 addSuccessor(ExitConditionBlock, nullptr);
4260 }
4261
4262 // Link up the condition block with the code that follows the loop.
4263 // (the false branch).
4264 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4265
4266 // There can be no more statements in the body block(s) since we loop back to
4267 // the body. NULL out Block to force lazy creation of another block.
4268 Block = nullptr;
4269
4270 // Return the loop body, which is the dominating block for the loop.
4271 Succ = BodyBlock;
4272 return BodyBlock;
4273}
4274
4275CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
4276 // "continue" is a control-flow statement. Thus we stop processing the
4277 // current block.
4278 if (badCFG)
4279 return nullptr;
4280
4281 // Now create a new block that ends with the continue statement.
4282 Block = createBlock(false);
4284
4285 // If there is no target for the continue, then we are looking at an
4286 // incomplete AST. This means the CFG cannot be constructed.
4287 if (ContinueJumpTarget.block) {
4288 addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
4289 addSuccessor(Block, ContinueJumpTarget.block);
4290 } else
4291 badCFG = true;
4292
4293 return Block;
4294}
4295
4296CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
4297 AddStmtChoice asc) {
4298 if (asc.alwaysAdd(*this, E)) {
4299 autoCreateBlock();
4300 appendStmt(Block, E);
4301 }
4302
4303 // VLA types have expressions that must be evaluated.
4304 // Evaluation is done only for `sizeof`.
4305
4306 if (E->getKind() != UETT_SizeOf)
4307 return Block;
4308
4309 CFGBlock *lastBlock = Block;
4310
4311 if (E->isArgumentType()) {
4312 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
4313 VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
4314 lastBlock = addStmt(VA->getSizeExpr());
4315 }
4316 return lastBlock;
4317}
4318
4319/// VisitStmtExpr - Utility method to handle (nested) statement
4320/// expressions (a GCC extension).
4321CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
4322 if (asc.alwaysAdd(*this, SE)) {
4323 autoCreateBlock();
4324 appendStmt(Block, SE);
4325 }
4326 return VisitCompoundStmt(SE->getSubStmt(), /*ExternallyDestructed=*/true);
4327}
4328
4329CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
4330 // "switch" is a control-flow statement. Thus we stop processing the current
4331 // block.
4332 CFGBlock *SwitchSuccessor = nullptr;
4333
4334 // Save local scope position because in case of condition variable ScopePos
4335 // won't be restored when traversing AST.
4336 SaveAndRestore save_scope_pos(ScopePos);
4337
4338 // Create local scope for C++17 switch init-stmt if one exists.
4339 if (Stmt *Init = Terminator->getInit())
4340 addLocalScopeForStmt(Init);
4341
4342 // Create local scope for possible condition variable.
4343 // Store scope position. Add implicit destructor.
4344 if (VarDecl *VD = Terminator->getConditionVariable())
4345 addLocalScopeForVarDecl(VD);
4346
4347 addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
4348
4349 if (Block) {
4350 if (badCFG)
4351 return nullptr;
4352 SwitchSuccessor = Block;
4353 } else SwitchSuccessor = Succ;
4354
4355 // Save the current "switch" context.
4356 SaveAndRestore save_switch(SwitchTerminatedBlock),
4357 save_default(DefaultCaseBlock);
4358 SaveAndRestore save_break(BreakJumpTarget);
4359
4360 // Set the "default" case to be the block after the switch statement. If the
4361 // switch statement contains a "default:", this value will be overwritten with
4362 // the block for that code.
4363 DefaultCaseBlock = SwitchSuccessor;
4364
4365 // Create a new block that will contain the switch statement.
4366 SwitchTerminatedBlock = createBlock(false);
4367
4368 // Now process the switch body. The code after the switch is the implicit
4369 // successor.
4370 Succ = SwitchSuccessor;
4371 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
4372
4373 // When visiting the body, the case statements should automatically get linked
4374 // up to the switch. We also don't keep a pointer to the body, since all
4375 // control-flow from the switch goes to case/default statements.
4376 assert(Terminator->getBody() && "switch must contain a non-NULL body");
4377 Block = nullptr;
4378
4379 // For pruning unreachable case statements, save the current state
4380 // for tracking the condition value.
4381 SaveAndRestore save_switchExclusivelyCovered(switchExclusivelyCovered, false);
4382
4383 // Determine if the switch condition can be explicitly evaluated.
4384 assert(Terminator->getCond() && "switch condition must be non-NULL");
4385 Expr::EvalResult result;
4386 bool b = tryEvaluate(Terminator->getCond(), result);
4387 SaveAndRestore save_switchCond(switchCond, b ? &result : nullptr);
4388
4389 // If body is not a compound statement create implicit scope
4390 // and add destructors.
4391 if (!isa<CompoundStmt>(Terminator->getBody()))
4392 addLocalScopeAndDtors(Terminator->getBody());
4393
4394 addStmt(Terminator->getBody());
4395 if (Block) {
4396 if (badCFG)
4397 return nullptr;
4398 }
4399
4400 // If we have no "default:" case, the default transition is to the code
4401 // following the switch body. Moreover, take into account if all the
4402 // cases of a switch are covered (e.g., switching on an enum value).
4403 //
4404 // Note: We add a successor to a switch that is considered covered yet has no
4405 // case statements if the enumeration has no enumerators.
4406 bool SwitchAlwaysHasSuccessor = false;
4407 SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
4408 SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
4409 Terminator->getSwitchCaseList();
4410 addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
4411 !SwitchAlwaysHasSuccessor);
4412
4413 // Add the terminator and condition in the switch block.
4414 SwitchTerminatedBlock->setTerminator(Terminator);
4415 Block = SwitchTerminatedBlock;
4416 CFGBlock *LastBlock = addStmt(Terminator->getCond());
4417
4418 // If the SwitchStmt contains a condition variable, add both the
4419 // SwitchStmt and the condition variable initialization to the CFG.
4420 if (VarDecl *VD = Terminator->getConditionVariable()) {
4421 if (Expr *Init = VD->getInit()) {
4422 autoCreateBlock();
4423 appendStmt(Block, Terminator->getConditionVariableDeclStmt());
4424 LastBlock = addStmt(Init);
4425 maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
4426 }
4427 }
4428
4429 // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
4430 if (Stmt *Init = Terminator->getInit()) {
4431 autoCreateBlock();
4432 LastBlock = addStmt(Init);
4433 }
4434
4435 return LastBlock;
4436}
4437
4438static bool shouldAddCase(bool &switchExclusivelyCovered,
4439 const Expr::EvalResult *switchCond,
4440 const CaseStmt *CS,
4441 ASTContext &Ctx) {
4442 if (!switchCond)
4443 return true;
4444
4445 bool addCase = false;
4446
4447 if (!switchExclusivelyCovered) {
4448 if (switchCond->Val.isInt()) {
4449 // Evaluate the LHS of the case value.
4450 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
4451 const llvm::APSInt &condInt = switchCond->Val.getInt();
4452
4453 if (condInt == lhsInt) {
4454 addCase = true;
4455 switchExclusivelyCovered = true;
4456 }
4457 else if (condInt > lhsInt) {
4458 if (const Expr *RHS = CS->getRHS()) {
4459 // Evaluate the RHS of the case value.
4460 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
4461 if (V2 >= condInt) {
4462 addCase = true;
4463 switchExclusivelyCovered = true;
4464 }
4465 }
4466 }
4467 }
4468 else
4469 addCase = true;
4470 }
4471 return addCase;
4472}
4473
4474CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
4475 // CaseStmts are essentially labels, so they are the first statement in a
4476 // block.
4477 CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
4478
4479 if (Stmt *Sub = CS->getSubStmt()) {
4480 // For deeply nested chains of CaseStmts, instead of doing a recursion
4481 // (which can blow out the stack), manually unroll and create blocks
4482 // along the way.
4483 while (isa<CaseStmt>(Sub)) {
4484 CFGBlock *currentBlock = createBlock(false);
4485 currentBlock->setLabel(CS);
4486
4487 if (TopBlock)
4488 addSuccessor(LastBlock, currentBlock);
4489 else
4490 TopBlock = currentBlock;
4491
4492 addSuccessor(SwitchTerminatedBlock,
4493 shouldAddCase(switchExclusivelyCovered, switchCond,
4494 CS, *Context)
4495 ? currentBlock : nullptr);
4496
4497 LastBlock = currentBlock;
4498 CS = cast<CaseStmt>(Sub);
4499 Sub = CS->getSubStmt();
4500 }
4501
4502 addStmt(Sub);
4503 }
4504
4505 CFGBlock *CaseBlock = Block;
4506 if (!CaseBlock)
4507 CaseBlock = createBlock();
4508
4509 // Cases statements partition blocks, so this is the top of the basic block we
4510 // were processing (the "case XXX:" is the label).
4511 CaseBlock->setLabel(CS);
4512
4513 if (badCFG)
4514 return nullptr;
4515
4516 // Add this block to the list of successors for the block with the switch
4517 // statement.
4518 assert(SwitchTerminatedBlock);
4519 addSuccessor(SwitchTerminatedBlock, CaseBlock,
4520 shouldAddCase(switchExclusivelyCovered, switchCond,
4521 CS, *Context));
4522
4523 // We set Block to NULL to allow lazy creation of a new block (if necessary).
4524 Block = nullptr;
4525
4526 if (TopBlock) {
4527 addSuccessor(LastBlock, CaseBlock);
4528 Succ = TopBlock;
4529 } else {
4530 // This block is now the implicit successor of other blocks.
4531 Succ = CaseBlock;
4532 }
4533
4534 return Succ;
4535}
4536
4537CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4538 if (Terminator->getSubStmt())
4539 addStmt(Terminator->getSubStmt());
4540
4541 DefaultCaseBlock = Block;
4542
4543 if (!DefaultCaseBlock)
4544 DefaultCaseBlock = createBlock();
4545
4546 // Default statements partition blocks, so this is the top of the basic block
4547 // we were processing (the "default:" is the label).
4548 DefaultCaseBlock->setLabel(Terminator);
4549
4550 if (badCFG)
4551 return nullptr;
4552
4553 // Unlike case statements, we don't add the default block to the successors
4554 // for the switch statement immediately. This is done when we finish
4555 // processing the switch statement. This allows for the default case
4556 // (including a fall-through to the code after the switch statement) to always
4557 // be the last successor of a switch-terminated block.
4558
4559 // We set Block to NULL to allow lazy creation of a new block (if necessary).
4560 Block = nullptr;
4561
4562 // This block is now the implicit successor of other blocks.
4563 Succ = DefaultCaseBlock;
4564
4565 return DefaultCaseBlock;
4566}
4567
4568CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4569 // "try"/"catch" is a control-flow statement. Thus we stop processing the
4570 // current block.
4571 CFGBlock *TrySuccessor = nullptr;
4572
4573 if (Block) {
4574 if (badCFG)
4575 return nullptr;
4576 TrySuccessor = Block;
4577 } else
4578 TrySuccessor = Succ;
4579
4580 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4581
4582 // Create a new block that will contain the try statement.
4583 CFGBlock *NewTryTerminatedBlock = createBlock(false);
4584 // Add the terminator in the try block.
4585 NewTryTerminatedBlock->setTerminator(Terminator);
4586
4587 bool HasCatchAll = false;
4588 for (unsigned I = 0, E = Terminator->getNumHandlers(); I != E; ++I) {
4589 // The code after the try is the implicit successor.
4590 Succ = TrySuccessor;
4591 CXXCatchStmt *CS = Terminator->getHandler(I);
4592 if (CS->getExceptionDecl() == nullptr) {
4593 HasCatchAll = true;
4594 }
4595 Block = nullptr;
4596 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4597 if (!CatchBlock)
4598 return nullptr;
4599 // Add this block to the list of successors for the block with the try
4600 // statement.
4601 addSuccessor(NewTryTerminatedBlock, CatchBlock);
4602 }
4603 if (!HasCatchAll) {
4604 if (PrevTryTerminatedBlock)
4605 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4606 else
4607 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4608 }
4609
4610 // The code after the try is the implicit successor.
4611 Succ = TrySuccessor;
4612
4613 // Save the current "try" context.
4614 SaveAndRestore SaveTry(TryTerminatedBlock, NewTryTerminatedBlock);
4615 cfg->addTryDispatchBlock(TryTerminatedBlock);
4616
4617 assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4618 Block = nullptr;
4619 return addStmt(Terminator->getTryBlock());
4620}
4621
4622CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4623 // CXXCatchStmt are treated like labels, so they are the first statement in a
4624 // block.
4625
4626 // Save local scope position because in case of exception variable ScopePos
4627 // won't be restored when traversing AST.
4628 SaveAndRestore save_scope_pos(ScopePos);
4629
4630 // Create local scope for possible exception variable.
4631 // Store scope position. Add implicit destructor.
4632 if (VarDecl *VD = CS->getExceptionDecl()) {
4633 LocalScope::const_iterator BeginScopePos = ScopePos;
4634 addLocalScopeForVarDecl(VD);
4635 addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4636 }
4637
4638 if (CS->getHandlerBlock())
4639 addStmt(CS->getHandlerBlock());
4640
4641 CFGBlock *CatchBlock = Block;
4642 if (!CatchBlock)
4643 CatchBlock = createBlock();
4644
4645 // CXXCatchStmt is more than just a label. They have semantic meaning
4646 // as well, as they implicitly "initialize" the catch variable. Add
4647 // it to the CFG as a CFGElement so that the control-flow of these
4648 // semantics gets captured.
4649 appendStmt(CatchBlock, CS);
4650
4651 // Also add the CXXCatchStmt as a label, to mirror handling of regular
4652 // labels.
4653 CatchBlock->setLabel(CS);
4654
4655 // Bail out if the CFG is bad.
4656 if (badCFG)
4657 return nullptr;
4658
4659 // We set Block to NULL to allow lazy creation of a new block (if necessary).
4660 Block = nullptr;
4661
4662 return CatchBlock;
4663}
4664
4665CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4666 // C++0x for-range statements are specified as [stmt.ranged]:
4667 //
4668 // {
4669 // auto && __range = range-init;
4670 // for ( auto __begin = begin-expr,
4671 // __end = end-expr;
4672 // __begin != __end;
4673 // ++__begin ) {
4674 // for-range-declaration = *__begin;
4675 // statement
4676 // }
4677 // }
4678
4679 // Save local scope position before the addition of the implicit variables.
4680 SaveAndRestore save_scope_pos(ScopePos);
4681
4682 // Create local scopes and destructors for range, begin and end variables.
4683 if (Stmt *Range = S->getRangeStmt())
4684 addLocalScopeForStmt(Range);
4685 if (Stmt *Begin = S->getBeginStmt())
4686 addLocalScopeForStmt(Begin);
4687 if (Stmt *End = S->getEndStmt())
4688 addLocalScopeForStmt(End);
4689 addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4690
4691 LocalScope::const_iterator ContinueScopePos = ScopePos;
4692
4693 // "for" is a control-flow statement. Thus we stop processing the current
4694 // block.
4695 CFGBlock *LoopSuccessor = nullptr;
4696 if (Block) {
4697 if (badCFG)
4698 return nullptr;
4699 LoopSuccessor = Block;
4700 } else
4701 LoopSuccessor = Succ;
4702
4703 // Save the current value for the break targets.
4704 // All breaks should go to the code following the loop.
4705 SaveAndRestore save_break(BreakJumpTarget);
4706 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4707
4708 // The block for the __begin != __end expression.
4709 CFGBlock *ConditionBlock = createBlock(false);
4710 ConditionBlock->setTerminator(S);
4711
4712 // Now add the actual condition to the condition block.
4713 if (Expr *C = S->getCond()) {
4714 Block = ConditionBlock;
4715 CFGBlock *BeginConditionBlock = addStmt(C);
4716 if (badCFG)
4717 return nullptr;
4718 assert(BeginConditionBlock == ConditionBlock &&
4719 "condition block in for-range was unexpectedly complex");
4720 (void)BeginConditionBlock;
4721 }
4722
4723 // The condition block is the implicit successor for the loop body as well as
4724 // any code above the loop.
4725 Succ = ConditionBlock;
4726
4727 // See if this is a known constant.
4728 TryResult KnownVal(true);
4729
4730 if (S->getCond())
4731 KnownVal = tryEvaluateBool(S->getCond());
4732
4733 // Now create the loop body.
4734 {
4735 assert(S->getBody());
4736
4737 // Save the current values for Block, Succ, and continue targets.
4738 SaveAndRestore save_Block(Block), save_Succ(Succ);
4739 SaveAndRestore save_continue(ContinueJumpTarget);
4740
4741 // Generate increment code in its own basic block. This is the target of
4742 // continue statements.
4743 Block = nullptr;
4744 Succ = addStmt(S->getInc());
4745 if (badCFG)
4746 return nullptr;
4747 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4748
4749 // The starting block for the loop increment is the block that should
4750 // represent the 'loop target' for looping back to the start of the loop.
4751 ContinueJumpTarget.block->setLoopTarget(S);
4752
4753 // Finish up the increment block and prepare to start the loop body.
4754 assert(Block);
4755 if (badCFG)
4756 return nullptr;
4757 Block = nullptr;
4758
4759 // Add implicit scope and dtors for loop variable.
4760 addLocalScopeAndDtors(S->getLoopVarStmt());
4761
4762 // If body is not a compound statement create implicit scope
4763 // and add destructors.
4764 if (!isa<CompoundStmt>(S->getBody()))
4765 addLocalScopeAndDtors(S->getBody());
4766
4767 // Populate a new block to contain the loop body and loop variable.
4768 addStmt(S->getBody());
4769
4770 if (badCFG)
4771 return nullptr;
4772 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4773 if (badCFG)
4774 return nullptr;
4775
4776 // This new body block is a successor to our condition block.
4777 addSuccessor(ConditionBlock,
4778 KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4779 }
4780
4781 // Link up the condition block with the code that follows the loop (the
4782 // false branch).
4783 addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4784
4785 // Add the initialization statements.
4786 Block = createBlock();
4787 addStmt(S->getBeginStmt());
4788 addStmt(S->getEndStmt());
4789 CFGBlock *Head = addStmt(S->getRangeStmt());
4790 if (S->getInit())
4791 Head = addStmt(S->getInit());
4792 return Head;
4793}
4794
4795CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4796 AddStmtChoice asc, bool ExternallyDestructed) {
4797 if (BuildOpts.AddTemporaryDtors) {
4798 // If adding implicit destructors visit the full expression for adding
4799 // destructors of temporaries.
4800 TempDtorContext Context;
4801 VisitForTemporaryDtors(E->getSubExpr(), ExternallyDestructed, Context);
4802
4803 // Full expression has to be added as CFGStmt so it will be sequenced
4804 // before destructors of it's temporaries.
4805 asc = asc.withAlwaysAdd(true);
4806 }
4807 return Visit(E->getSubExpr(), asc);
4808}
4809
4810CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4811 AddStmtChoice asc) {
4812 if (asc.alwaysAdd(*this, E)) {
4813 autoCreateBlock();
4814 appendStmt(Block, E);
4815
4816 findConstructionContexts(
4817 ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4818 E->getSubExpr());
4819
4820 // We do not want to propagate the AlwaysAdd property.
4821 asc = asc.withAlwaysAdd(false);
4822 }
4823 return Visit(E->getSubExpr(), asc);
4824}
4825
4826CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4827 AddStmtChoice asc) {
4828 // If the constructor takes objects as arguments by value, we need to properly
4829 // construct these objects. Construction contexts we find here aren't for the
4830 // constructor C, they're for its arguments only.
4831 findConstructionContextsForArguments(C);
4832
4833 autoCreateBlock();
4834 appendConstructor(Block, C);
4835
4836 return VisitChildren(C);
4837}
4838
4839CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4840 AddStmtChoice asc) {
4841 autoCreateBlock();
4842 appendStmt(Block, NE);
4843
4844 findConstructionContexts(
4845 ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4846 const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4847
4848 if (NE->getInitializer())
4849 Block = Visit(NE->getInitializer());
4850
4851 if (BuildOpts.AddCXXNewAllocator)
4852 appendNewAllocator(Block, NE);
4853
4854 if (NE->isArray() && *NE->getArraySize())
4855 Block = Visit(*NE->getArraySize());
4856
4857 for (CXXNewExpr::arg_iterator I = NE->placement_arg_begin(),
4858 E = NE->placement_arg_end(); I != E; ++I)
4859 Block = Visit(*I);
4860
4861 return Block;
4862}
4863
4864CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4865 AddStmtChoice asc) {
4866 autoCreateBlock();
4867 appendStmt(Block, DE);
4868 QualType DTy = DE->getDestroyedType();
4869 if (!DTy.isNull()) {
4870 DTy = DTy.getNonReferenceType();
4872 if (RD) {
4873 if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4874 appendDeleteDtor(Block, RD, DE);
4875 }
4876 }
4877
4878 return VisitChildren(DE);
4879}
4880
4881CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4882 AddStmtChoice asc) {
4883 if (asc.alwaysAdd(*this, E)) {
4884 autoCreateBlock();
4885 appendStmt(Block, E);
4886 // We do not want to propagate the AlwaysAdd property.
4887 asc = asc.withAlwaysAdd(false);
4888 }
4889 return Visit(E->getSubExpr(), asc);
4890}
4891
4892CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4893 AddStmtChoice asc) {
4894 // If the constructor takes objects as arguments by value, we need to properly
4895 // construct these objects. Construction contexts we find here aren't for the
4896 // constructor C, they're for its arguments only.
4897 findConstructionContextsForArguments(C);
4898
4899 autoCreateBlock();
4900 appendConstructor(Block, C);
4901 return VisitChildren(C);
4902}
4903
4904CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4905 AddStmtChoice asc) {
4906 if (asc.alwaysAdd(*this, E)) {
4907 autoCreateBlock();
4908 appendStmt(Block, E);
4909 }
4910
4911 if (E->getCastKind() == CK_IntegralToBoolean)
4912 tryEvaluateBool(E->getSubExpr()->IgnoreParens());
4913
4914 return Visit(E->getSubExpr(), AddStmtChoice());
4915}
4916
4917CFGBlock *CFGBuilder::VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc) {
4918 return Visit(E->getSubExpr(), AddStmtChoice());
4919}
4920
4921CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4922 // Lazily create the indirect-goto dispatch block if there isn't one already.
4923 CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4924
4925 if (!IBlock) {
4926 IBlock = createBlock(false);
4927 cfg->setIndirectGotoBlock(IBlock);
4928 }
4929
4930 // IndirectGoto is a control-flow statement. Thus we stop processing the
4931 // current block and create a new one.
4932 if (badCFG)
4933 return nullptr;
4934
4935 Block = createBlock(false);
4936 Block->setTerminator(I);
4937 addSuccessor(Block, IBlock);
4938 return addStmt(I->getTarget());
4939}
4940
4941CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool ExternallyDestructed,
4942 TempDtorContext &Context) {
4943 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4944
4945tryAgain:
4946 if (!E) {
4947 badCFG = true;
4948 return nullptr;
4949 }
4950 switch (E->getStmtClass()) {
4951 default:
4952 return VisitChildrenForTemporaryDtors(E, false, Context);
4953
4954 case Stmt::InitListExprClass:
4955 return VisitChildrenForTemporaryDtors(E, ExternallyDestructed, Context);
4956
4957 case Stmt::BinaryOperatorClass:
4958 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4959 ExternallyDestructed,
4960 Context);
4961
4962 case Stmt::CXXBindTemporaryExprClass:
4963 return VisitCXXBindTemporaryExprForTemporaryDtors(
4964 cast<CXXBindTemporaryExpr>(E), ExternallyDestructed, Context);
4965
4966 case Stmt::BinaryConditionalOperatorClass:
4967 case Stmt::ConditionalOperatorClass:
4968 return VisitConditionalOperatorForTemporaryDtors(
4969 cast<AbstractConditionalOperator>(E), ExternallyDestructed, Context);
4970
4971 case Stmt::ImplicitCastExprClass:
4972 // For implicit cast we want ExternallyDestructed to be passed further.
4973 E = cast<CastExpr>(E)->getSubExpr();
4974 goto tryAgain;
4975
4976 case Stmt::CXXFunctionalCastExprClass:
4977 // For functional cast we want ExternallyDestructed to be passed further.
4978 E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4979 goto tryAgain;
4980
4981 case Stmt::ConstantExprClass:
4982 E = cast<ConstantExpr>(E)->getSubExpr();
4983 goto tryAgain;
4984
4985 case Stmt::ParenExprClass:
4986 E = cast<ParenExpr>(E)->getSubExpr();
4987 goto tryAgain;
4988
4989 case Stmt::MaterializeTemporaryExprClass: {
4990 const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4991 ExternallyDestructed = (MTE->getStorageDuration() != SD_FullExpression);
4994 // Find the expression whose lifetime needs to be extended.
4995 E = const_cast<Expr *>(
4996 cast<MaterializeTemporaryExpr>(E)
4997 ->getSubExpr()
4998 ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4999 // Visit the skipped comma operator left-hand sides for other temporaries.
5000 for (const Expr *CommaLHS : CommaLHSs) {
5001 VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
5002 /*ExternallyDestructed=*/false, Context);
5003 }
5004 goto tryAgain;
5005 }
5006
5007 case Stmt::BlockExprClass:
5008 // Don't recurse into blocks; their subexpressions don't get evaluated
5009 // here.
5010 return Block;
5011
5012 case Stmt::LambdaExprClass: {
5013 // For lambda expressions, only recurse into the capture initializers,
5014 // and not the body.
5015 auto *LE = cast<LambdaExpr>(E);
5016 CFGBlock *B = Block;
5017 for (Expr *Init : LE->capture_inits()) {
5018 if (Init) {
5019 if (CFGBlock *R = VisitForTemporaryDtors(
5020 Init, /*ExternallyDestructed=*/true, Context))
5021 B = R;
5022 }
5023 }
5024 return B;
5025 }
5026
5027 case Stmt::StmtExprClass:
5028 // Don't recurse into statement expressions; any cleanups inside them
5029 // will be wrapped in their own ExprWithCleanups.
5030 return Block;
5031
5032 case Stmt::CXXDefaultArgExprClass:
5033 E = cast<CXXDefaultArgExpr>(E)->getExpr();
5034 goto tryAgain;
5035
5036 case Stmt::CXXDefaultInitExprClass:
5037 E = cast<CXXDefaultInitExpr>(E)->getExpr();
5038 goto tryAgain;
5039 }
5040}
5041
5042CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
5043 bool ExternallyDestructed,
5044 TempDtorContext &Context) {
5045 if (isa<LambdaExpr>(E)) {
5046 // Do not visit the children of lambdas; they have their own CFGs.
5047 return Block;
5048 }
5049
5050 // When visiting children for destructors we want to visit them in reverse
5051 // order that they will appear in the CFG. Because the CFG is built
5052 // bottom-up, this means we visit them in their natural order, which
5053 // reverses them in the CFG.
5054 CFGBlock *B = Block;
5055 for (Stmt *Child : E->children())
5056 if (Child)
5057 if (CFGBlock *R = VisitForTemporaryDtors(Child, ExternallyDestructed, Context))
5058 B = R;
5059
5060 return B;
5061}
5062
5063CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
5064 BinaryOperator *E, bool ExternallyDestructed, TempDtorContext &Context) {
5065 if (E->isCommaOp()) {
5066 // For the comma operator, the LHS expression is evaluated before the RHS
5067 // expression, so prepend temporary destructors for the LHS first.
5068 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
5069 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), ExternallyDestructed, Context);
5070 return RHSBlock ? RHSBlock : LHSBlock;
5071 }
5072
5073 if (E->isLogicalOp()) {
5074 VisitForTemporaryDtors(E->getLHS(), false, Context);
5075 TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
5076 if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
5077 RHSExecuted.negate();
5078
5079 // We do not know at CFG-construction time whether the right-hand-side was
5080 // executed, thus we add a branch node that depends on the temporary
5081 // constructor call.
5082 TempDtorContext RHSContext(
5083 bothKnownTrue(Context.KnownExecuted, RHSExecuted));
5084 VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
5085 InsertTempDtorDecisionBlock(RHSContext);
5086
5087 return Block;
5088 }
5089
5090 if (E->isAssignmentOp()) {
5091 // For assignment operators, the RHS expression is evaluated before the LHS
5092 // expression, so prepend temporary destructors for the RHS first.
5093 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
5094 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
5095 return LHSBlock ? LHSBlock : RHSBlock;
5096 }
5097
5098 // Any other operator is visited normally.
5099 return VisitChildrenForTemporaryDtors(E, ExternallyDestructed, Context);
5100}
5101
5102CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
5103 CXXBindTemporaryExpr *E, bool ExternallyDestructed, TempDtorContext &Context) {
5104 // First add destructors for temporaries in subexpression.
5105 // Because VisitCXXBindTemporaryExpr calls setDestructed:
5106 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), true, Context);
5107 if (!ExternallyDestructed) {
5108 // If lifetime of temporary is not prolonged (by assigning to constant
5109 // reference) add destructor for it.
5110
5111 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
5112
5113 if (Dtor->getParent()->isAnyDestructorNoReturn()) {
5114 // If the destructor is marked as a no-return destructor, we need to
5115 // create a new block for the destructor which does not have as a
5116 // successor anything built thus far. Control won't flow out of this
5117 // block.
5118 if (B) Succ = B;
5119 Block = createNoReturnBlock();
5120 } else if (Context.needsTempDtorBranch()) {
5121 // If we need to introduce a branch, we add a new block that we will hook
5122 // up to a decision block later.
5123 if (B) Succ = B;
5124 Block = createBlock();
5125 } else {
5126 autoCreateBlock();
5127 }
5128 if (Context.needsTempDtorBranch()) {
5129 Context.setDecisionPoint(Succ, E);
5130 }
5131 appendTemporaryDtor(Block, E);
5132
5133 B = Block;
5134 }
5135 return B;
5136}
5137
5138void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
5139 CFGBlock *FalseSucc) {
5140 if (!Context.TerminatorExpr) {
5141 // If no temporary was found, we do not need to insert a decision point.
5142 return;
5143 }
5144 assert(Context.TerminatorExpr);
5145 CFGBlock *Decision = createBlock(false);
5146 Decision->setTerminator(CFGTerminator(Context.TerminatorExpr,
5148 addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
5149 addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
5150 !Context.KnownExecuted.isTrue());
5151 Block = Decision;
5152}
5153
5154CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
5155 AbstractConditionalOperator *E, bool ExternallyDestructed,
5156 TempDtorContext &Context) {
5157 VisitForTemporaryDtors(E->getCond(), false, Context);
5158 CFGBlock *ConditionBlock = Block;
5159 CFGBlock *ConditionSucc = Succ;
5160 TryResult ConditionVal = tryEvaluateBool(E->getCond());
5161 TryResult NegatedVal = ConditionVal;
5162 if (NegatedVal.isKnown()) NegatedVal.negate();
5163
5164 TempDtorContext TrueContext(
5165 bothKnownTrue(Context.KnownExecuted, ConditionVal));
5166 VisitForTemporaryDtors(E->getTrueExpr(), ExternallyDestructed, TrueContext);
5167 CFGBlock *TrueBlock = Block;
5168
5169 Block = ConditionBlock;
5170 Succ = ConditionSucc;
5171 TempDtorContext FalseContext(
5172 bothKnownTrue(Context.KnownExecuted, NegatedVal));
5173 VisitForTemporaryDtors(E->getFalseExpr(), ExternallyDestructed, FalseContext);
5174
5175 if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
5176 InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
5177 } else if (TrueContext.TerminatorExpr) {
5178 Block = TrueBlock;
5179 InsertTempDtorDecisionBlock(TrueContext);
5180 } else {
5181 InsertTempDtorDecisionBlock(FalseContext);
5182 }
5183 return Block;
5184}
5185
5186CFGBlock *CFGBuilder::VisitOMPExecutableDirective(OMPExecutableDirective *D,
5187 AddStmtChoice asc) {
5188 if (asc.alwaysAdd(*this, D)) {
5189 autoCreateBlock();
5190 appendStmt(Block, D);
5191 }
5192
5193 // Iterate over all used expression in clauses.
5194 CFGBlock *B = Block;
5195
5196 // Reverse the elements to process them in natural order. Iterators are not
5197 // bidirectional, so we need to create temp vector.
5200 for (Stmt *S : llvm::reverse(Used)) {
5201 assert(S && "Expected non-null used-in-clause child.");
5202 if (CFGBlock *R = Visit(S))
5203 B = R;
5204 }
5205 // Visit associated structured block if any.
5206 if (!D->isStandaloneDirective()) {
5207 Stmt *S = D->getRawStmt();
5208 if (!isa<CompoundStmt>(S))
5209 addLocalScopeAndDtors(S);
5210 if (CFGBlock *R = addStmt(S))
5211 B = R;
5212 }
5213
5214 return B;
5215}
5216
5217/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
5218/// no successors or predecessors. If this is the first block created in the
5219/// CFG, it is automatically set to be the Entry and Exit of the CFG.
5221 bool first_block = begin() == end();
5222
5223 // Create the block.
5224 CFGBlock *Mem = new (getAllocator()) CFGBlock(NumBlockIDs++, BlkBVC, this);
5225 Blocks.push_back(Mem, BlkBVC);
5226
5227 // If this is the first block, set it as the Entry and Exit.
5228 if (first_block)
5229 Entry = Exit = &back();
5230
5231 // Return the block.
5232 return &back();
5233}
5234
5235/// buildCFG - Constructs a CFG from an AST.
5236std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
5237 ASTContext *C, const BuildOptions &BO) {
5238 CFGBuilder Builder(C, BO);
5239 return Builder.buildCFG(D, Statement);
5240}
5241
5242bool CFG::isLinear() const {
5243 // Quick path: if we only have the ENTRY block, the EXIT block, and some code
5244 // in between, then we have no room for control flow.
5245 if (size() <= 3)
5246 return true;
5247
5248 // Traverse the CFG until we find a branch.
5249 // TODO: While this should still be very fast,
5250 // maybe we should cache the answer.
5252 const CFGBlock *B = Entry;
5253 while (B != Exit) {
5254 auto IteratorAndFlag = Visited.insert(B);
5255 if (!IteratorAndFlag.second) {
5256 // We looped back to a block that we've already visited. Not linear.
5257 return false;
5258 }
5259
5260 // Iterate over reachable successors.
5261 const CFGBlock *FirstReachableB = nullptr;
5262 for (const CFGBlock::AdjacentBlock &AB : B->succs()) {
5263 if (!AB.isReachable())
5264 continue;
5265
5266 if (FirstReachableB == nullptr) {
5267 FirstReachableB = &*AB;
5268 } else {
5269 // We've encountered a branch. It's not a linear CFG.
5270 return false;
5271 }
5272 }
5273
5274 if (!FirstReachableB) {
5275 // We reached a dead end. EXIT is unreachable. This is linear enough.
5276 return true;
5277 }
5278
5279 // There's only one way to move forward. Proceed.
5280 B = FirstReachableB;
5281 }
5282
5283 // We reached EXIT and found no branches.
5284 return true;
5285}
5286
5287const CXXDestructorDecl *
5289 switch (getKind()) {
5300 llvm_unreachable("getDestructorDecl should only be used with "
5301 "ImplicitDtors");
5303 const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
5304 QualType ty = var->getType();
5305
5306 // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
5307 //
5308 // Lifetime-extending constructs are handled here. This works for a single
5309 // temporary in an initializer expression.
5310 if (ty->isReferenceType()) {
5311 if (const Expr *Init = var->getInit()) {
5313 }
5314 }
5315
5316 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
5317 ty = arrayType->getElementType();
5318 }
5319
5320 // The situation when the type of the lifetime-extending reference
5321 // does not correspond to the type of the object is supposed
5322 // to be handled by now. In particular, 'ty' is now the unwrapped
5323 // record type.
5324 const CXXRecordDecl *classDecl = ty->getAsCXXRecordDecl();
5325 assert(classDecl);
5326 return classDecl->getDestructor();
5327 }
5329 const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
5330 QualType DTy = DE->getDestroyedType();
5331 DTy = DTy.getNonReferenceType();
5332 const CXXRecordDecl *classDecl =
5333 astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
5334 return classDecl->getDestructor();
5335 }
5337 const CXXBindTemporaryExpr *bindExpr =
5338 castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
5339 const CXXTemporary *temp = bindExpr->getTemporary();
5340 return temp->getDestructor();
5341 }
5343 const FieldDecl *field = castAs<CFGMemberDtor>().getFieldDecl();
5344 QualType ty = field->getType();
5345
5346 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
5347 ty = arrayType->getElementType();
5348 }
5349
5350 const CXXRecordDecl *classDecl = ty->getAsCXXRecordDecl();
5351 assert(classDecl);
5352 return classDecl->getDestructor();
5353 }
5355 // Not yet supported.
5356 return nullptr;
5357 }
5358 llvm_unreachable("getKind() returned bogus value");
5359}
5360
5361//===----------------------------------------------------------------------===//
5362// CFGBlock operations.
5363//===----------------------------------------------------------------------===//
5364
5366 : ReachableBlock(IsReachable ? B : nullptr),
5367 UnreachableBlock(!IsReachable ? B : nullptr,
5368 B && IsReachable ? AB_Normal : AB_Unreachable) {}
5369
5371 : ReachableBlock(B),
5372 UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
5373 B == AlternateBlock ? AB_Alternate : AB_Normal) {}
5374
5377 if (CFGBlock *B = Succ.getReachableBlock())
5378 B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
5379
5380 if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
5381 UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
5382
5383 Succs.push_back(Succ, C);
5384}
5385
5387 const CFGBlock *From, const CFGBlock *To) {
5388 if (F.IgnoreNullPredecessors && !From)
5389 return true;
5390
5391 if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
5392 // If the 'To' has no label or is labeled but the label isn't a
5393 // CaseStmt then filter this edge.
5394 if (const SwitchStmt *S =
5395 dyn_cast_or_null<SwitchStmt>(From->getTerminatorStmt())) {
5396 if (S->isAllEnumCasesCovered()) {
5397 const Stmt *L = To->getLabel();
5398 if (!L || !isa<CaseStmt>(L))
5399 return true;
5400 }
5401 }
5402 }
5403
5404 return false;
5405}
5406
5407//===----------------------------------------------------------------------===//
5408// CFG pretty printing
5409//===----------------------------------------------------------------------===//
5410
5411namespace {
5412
5413class StmtPrinterHelper : public PrinterHelper {
5414 using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
5415 using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
5416
5417 StmtMapTy StmtMap;
5418 DeclMapTy DeclMap;
5419 signed currentBlock = 0;
5420 unsigned currStmt = 0;
5421 const LangOptions &LangOpts;
5422
5423public:
5424 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
5425 : LangOpts(LO) {
5426 if (!cfg)
5427 return;
5428 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
5429 unsigned j = 1;
5430 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
5431 BI != BEnd; ++BI, ++j ) {
5432 if (std::optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
5433 const Stmt *stmt= SE->getStmt();
5434 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
5435 StmtMap[stmt] = P;
5436
5437 switch (stmt->getStmtClass()) {
5438 case Stmt::DeclStmtClass:
5439 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
5440 break;
5441 case Stmt::IfStmtClass: {
5442 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
5443 if (var)
5444 DeclMap[var] = P;
5445 break;
5446 }
5447 case Stmt::ForStmtClass: {
5448 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
5449 if (var)
5450 DeclMap[var] = P;
5451 break;
5452 }
5453 case Stmt::WhileStmtClass: {
5454 const VarDecl *var =
5455 cast<WhileStmt>(stmt)->getConditionVariable();
5456 if (var)
5457 DeclMap[var] = P;
5458 break;
5459 }
5460 case Stmt::SwitchStmtClass: {
5461 const VarDecl *var =
5462 cast<SwitchStmt>(stmt)->getConditionVariable();
5463 if (var)
5464 DeclMap[var] = P;
5465 break;
5466 }
5467 case Stmt::CXXCatchStmtClass: {
5468 const VarDecl *var =
5469 cast<CXXCatchStmt>(stmt)->getExceptionDecl();
5470 if (var)
5471 DeclMap[var] = P;
5472 break;
5473 }
5474 default:
5475 break;
5476 }
5477 }
5478 }
5479 }
5480 }
5481
5482 ~StmtPrinterHelper() override = default;
5483
5484 const LangOptions &getLangOpts() const { return LangOpts; }
5485 void setBlockID(signed i) { currentBlock = i; }
5486 void setStmtID(unsigned i) { currStmt = i; }
5487
5488 bool handledStmt(Stmt *S, raw_ostream &OS) override {
5489 StmtMapTy::iterator I = StmtMap.find(S);
5490
5491 if (I == StmtMap.end())
5492 return false;
5493
5494 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
5495 && I->second.second == currStmt) {
5496 return false;
5497 }
5498
5499 OS << "[B" << I->second.first << "." << I->second.second << "]";
5500 return true;
5501 }
5502
5503 bool handleDecl(const Decl *D, raw_ostream &OS) {
5504 DeclMapTy::iterator I = DeclMap.find(D);
5505
5506 if (I == DeclMap.end())
5507 return false;
5508
5509 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
5510 && I->second.second == currStmt) {
5511 return false;
5512 }
5513
5514 OS << "[B" << I->second.first << "." << I->second.second << "]";
5515 return true;
5516 }
5517};
5518
5519class CFGBlockTerminatorPrint
5520 : public StmtVisitor<CFGBlockTerminatorPrint,void> {
5521 raw_ostream &OS;
5522 StmtPrinterHelper* Helper;
5523 PrintingPolicy Policy;
5524
5525public:
5526 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
5527 const PrintingPolicy &Policy)
5528 : OS(os), Helper(helper), Policy(Policy) {
5529 this->Policy.IncludeNewlines = false;
5530 }
5531
5532 void VisitIfStmt(IfStmt *I) {
5533 OS << "if ";
5534 if (Stmt *C = I->getCond())
5535 C->printPretty(OS, Helper, Policy);
5536 }
5537
5538 // Default case.
5539 void VisitStmt(Stmt *Terminator) {
5540 Terminator->printPretty(OS, Helper, Policy);
5541 }
5542
5543 void VisitDeclStmt(DeclStmt *DS) {
5544 VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
5545 OS << "static init " << VD->getName();
5546 }
5547
5548 void VisitForStmt(ForStmt *F) {
5549 OS << "for (" ;
5550 if (F->getInit())
5551 OS << "...";
5552 OS << "; ";
5553 if (Stmt *C = F->getCond())
5554 C->printPretty(OS, Helper, Policy);
5555 OS << "; ";
5556 if (F->getInc())
5557 OS << "...";
5558 OS << ")";
5559 }
5560
5561 void VisitWhileStmt(WhileStmt *W) {
5562 OS << "while " ;
5563 if (Stmt *C = W->getCond())
5564 C->printPretty(OS, Helper, Policy);
5565 }
5566
5567 void VisitDoStmt(DoStmt *D) {
5568 OS << "do ... while ";
5569 if (Stmt *C = D->getCond())
5570 C->printPretty(OS, Helper, Policy);
5571 }
5572
5573 void VisitSwitchStmt(SwitchStmt *Terminator) {
5574 OS << "switch ";
5575 Terminator->getCond()->printPretty(OS, Helper, Policy);
5576 }
5577
5578 void VisitCXXTryStmt(CXXTryStmt *) { OS << "try ..."; }
5579
5580 void VisitObjCAtTryStmt(ObjCAtTryStmt *) { OS << "@try ..."; }
5581
5582 void VisitSEHTryStmt(SEHTryStmt *CS) { OS << "__try ..."; }
5583
5584 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
5585 if (Stmt *Cond = C->getCond())
5586 Cond->printPretty(OS, Helper, Policy);
5587 OS << " ? ... : ...";
5588 }
5589
5590 void VisitChooseExpr(ChooseExpr *C) {
5591 OS << "__builtin_choose_expr( ";
5592 if (Stmt *Cond = C->getCond())
5593 Cond->printPretty(OS, Helper, Policy);
5594 OS << " )";
5595 }
5596
5597 void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
5598 OS << "goto *";
5599 if (Stmt *T = I->getTarget())
5600 T->printPretty(OS, Helper, Policy);
5601 }
5602
5603 void VisitBinaryOperator(BinaryOperator* B) {
5604 if (!B->isLogicalOp()) {
5605 VisitExpr(B);
5606 return;
5607 }
5608
5609 if (B->getLHS())
5610 B->getLHS()->printPretty(OS, Helper, Policy);
5611
5612 switch (B->getOpcode()) {
5613 case BO_LOr:
5614 OS << " || ...";
5615 return;
5616 case BO_LAnd:
5617 OS << " && ...";
5618 return;
5619 default:
5620 llvm_unreachable("Invalid logical operator.");
5621 }
5622 }
5623
5624 void VisitExpr(Expr *E) {
5625 E->printPretty(OS, Helper, Policy);
5626 }
5627
5628public:
5629 void print(CFGTerminator T) {
5630 switch (T.getKind()) {
5632 Visit(T.getStmt());
5633 break;
5635 OS << "(Temp Dtor) ";
5636 Visit(T.getStmt());
5637 break;
5639 OS << "(See if most derived ctor has already initialized vbases)";
5640 break;
5641 }
5642 }
5643};
5644
5645} // namespace
5646
5647static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
5648 const CXXCtorInitializer *I) {
5649 if (I->isBaseInitializer())
5650 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
5651 else if (I->isDelegatingInitializer())
5653 else
5654 OS << I->getAnyMember()->getName();
5655 OS << "(";
5656 if (Expr *IE = I->getInit())
5657 IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5658 OS << ")";
5659
5660 if (I->isBaseInitializer())
5661 OS << " (Base initializer)";
5662 else if (I->isDelegatingInitializer())
5663 OS << " (Delegating initializer)";
5664 else
5665 OS << " (Member initializer)";
5666}
5667
5668static void print_construction_context(raw_ostream &OS,
5669 StmtPrinterHelper &Helper,
5670 const ConstructionContext *CC) {
5672 switch (CC->getKind()) {
5674 OS << ", ";
5675 const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5676 print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5677 return;
5678 }
5680 OS << ", ";
5681 const auto *CICC =
5682 cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5683 print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5684 Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5685 break;
5686 }
5688 const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5689 Stmts.push_back(SDSCC->getDeclStmt());
5690 break;
5691 }
5693 const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5694 Stmts.push_back(CDSCC->getDeclStmt());
5695 Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5696 break;
5697 }
5699 const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5700 Stmts.push_back(NECC->getCXXNewExpr());
5701 break;
5702 }
5704 const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5705 Stmts.push_back(RSCC->getReturnStmt());
5706 break;
5707 }
5709 const auto *RSCC =
5710 cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5711 Stmts.push_back(RSCC->getReturnStmt());
5712 Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5713 break;
5714 }
5716 const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5717 Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5718 Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5719 break;
5720 }
5722 const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5723 Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5724 Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5725 Stmts.push_back(TOCC->getConstructorAfterElision());
5726 break;
5727 }
5729 const auto *LCC = cast<LambdaCaptureConstructionContext>(CC);
5730 Helper.handledStmt(const_cast<LambdaExpr *>(LCC->getLambdaExpr()), OS);
5731 OS << "+" << LCC->getIndex();
5732 return;
5733 }
5735 const auto *ACC = cast<ArgumentConstructionContext>(CC);
5736 if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5737 OS << ", ";
5738 Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5739 }
5740 OS << ", ";
5741 Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5742 OS << "+" << ACC->getIndex();
5743 return;
5744 }
5745 }
5746 for (auto I: Stmts)
5747 if (I) {
5748 OS << ", ";
5749 Helper.handledStmt(const_cast<Stmt *>(I), OS);
5750 }
5751}
5752
5753static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5754 const CFGElement &E);
5755
5756void CFGElement::dumpToStream(llvm::raw_ostream &OS) const {
5757 LangOptions LangOpts;
5758 StmtPrinterHelper Helper(nullptr, LangOpts);
5759 print_elem(OS, Helper, *this);
5760}
5761
5762static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5763 const CFGElement &E) {
5764 switch (E.getKind()) {
5768 CFGStmt CS = E.castAs<CFGStmt>();
5769 const Stmt *S = CS.getStmt();
5770 assert(S != nullptr && "Expecting non-null Stmt");
5771
5772 // special printing for statement-expressions.
5773 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5774 const CompoundStmt *Sub = SE->getSubStmt();
5775
5776 auto Children = Sub->children();
5777 if (Children.begin() != Children.end()) {
5778 OS << "({ ... ; ";
5779 Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5780 OS << " })\n";
5781 return;
5782 }
5783 }
5784 // special printing for comma expressions.
5785 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5786 if (B->getOpcode() == BO_Comma) {
5787 OS << "... , ";
5788 Helper.handledStmt(B->getRHS(),OS);
5789 OS << '\n';
5790 return;
5791 }
5792 }
5793 S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5794
5795 if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5796 if (isa<CXXOperatorCallExpr>(S))
5797 OS << " (OperatorCall)";
5798 OS << " (CXXRecordTypedCall";
5799 print_construction_context(OS, Helper, VTC->getConstructionContext());
5800 OS << ")";
5801 } else if (isa<CXXOperatorCallExpr>(S)) {
5802 OS << " (OperatorCall)";
5803 } else if (isa<CXXBindTemporaryExpr>(S)) {
5804 OS << " (BindTemporary)";
5805 } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5806 OS << " (CXXConstructExpr";
5807 if (std::optional<CFGConstructor> CE = E.getAs<CFGConstructor>()) {
5808 print_construction_context(OS, Helper, CE->getConstructionContext());
5809 }
5810 OS << ", " << CCE->getType() << ")";
5811 } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5812 OS << " (" << CE->getStmtClassName() << ", " << CE->getCastKindName()
5813 << ", " << CE->getType() << ")";
5814 }
5815
5816 // Expressions need a newline.
5817 if (isa<Expr>(S))
5818 OS << '\n';
5819
5820 break;
5821 }
5822
5825 OS << '\n';
5826 break;
5827
5830 const VarDecl *VD = DE.getVarDecl();
5831 Helper.handleDecl(VD, OS);
5832
5833 QualType T = VD->getType();
5834 if (T->isReferenceType())
5835 T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5836
5837 OS << ".~";
5838 T.getUnqualifiedType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5839 OS << "() (Implicit destructor)\n";
5840 break;
5841 }
5842
5844 OS << "CleanupFunction ("
5845 << E.castAs<CFGCleanupFunction>().getFunctionDecl()->getName() << ")\n";
5846 break;
5847
5849 Helper.handleDecl(E.castAs<CFGLifetimeEnds>().getVarDecl(), OS);
5850 OS << " (Lifetime ends)\n";
5851 break;
5852
5854 OS << E.castAs<CFGLoopExit>().getLoopStmt()->getStmtClassName() << " (LoopExit)\n";
5855 break;
5856
5858 OS << "CFGScopeBegin(";
5859 if (const VarDecl *VD = E.castAs<CFGScopeBegin>().getVarDecl())
5860 OS << VD->getQualifiedNameAsString();
5861 OS << ")\n";
5862 break;
5863
5865 OS << "CFGScopeEnd(";
5866 if (const VarDecl *VD = E.castAs<CFGScopeEnd>().getVarDecl())
5867 OS << VD->getQualifiedNameAsString();
5868 OS << ")\n";
5869 break;
5870
5872 OS << "CFGNewAllocator(";
5873 if (const CXXNewExpr *AllocExpr = E.castAs<CFGNewAllocator>().getAllocatorExpr())
5874 AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5875 OS << ")\n";
5876 break;
5877
5880 const CXXRecordDecl *RD = DE.getCXXRecordDecl();
5881 if (!RD)
5882 return;
5883 CXXDeleteExpr *DelExpr =
5884 const_cast<CXXDeleteExpr*>(DE.getDeleteExpr());
5885 Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5886 OS << "->~" << RD->getName().str() << "()";
5887 OS << " (Implicit destructor)\n";