clang 19.0.0git
TransEmptyStatementsAndDealloc.cpp
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1//===-- TransEmptyStatementsAndDealloc.cpp - Transformations to ARC mode --===//
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// removeEmptyStatementsAndDealloc:
10//
11// Removes empty statements that are leftovers from previous transformations.
12// e.g for
13//
14// [x retain];
15//
16// removeRetainReleaseDealloc will leave an empty ";" that removeEmptyStatements
17// will remove.
18//
19//===----------------------------------------------------------------------===//
20
21#include "Transforms.h"
22#include "Internals.h"
26
27using namespace clang;
28using namespace arcmt;
29using namespace trans;
30
32 std::vector<SourceLocation> &MacroLocs,
33 ASTContext &Ctx) {
34 if (!S->hasLeadingEmptyMacro())
35 return false;
36
37 SourceLocation SemiLoc = S->getSemiLoc();
38 if (SemiLoc.isInvalid() || SemiLoc.isMacroID())
39 return false;
40
41 if (MacroLocs.empty())
42 return false;
43
45 std::vector<SourceLocation>::iterator I = llvm::upper_bound(
46 MacroLocs, SemiLoc, BeforeThanCompare<SourceLocation>(SM));
47 --I;
49 AfterMacroLoc = I->getLocWithOffset(getARCMTMacroName().size());
50 assert(AfterMacroLoc.isFileID());
51
52 if (AfterMacroLoc == SemiLoc)
53 return true;
54
55 SourceLocation::IntTy RelOffs = 0;
56 if (!SM.isInSameSLocAddrSpace(AfterMacroLoc, SemiLoc, &RelOffs))
57 return false;
58 if (RelOffs < 0)
59 return false;
60
61 // We make the reasonable assumption that a semicolon after 100 characters
62 // means that it is not the next token after our macro. If this assumption
63 // fails it is not critical, we will just fail to clear out, e.g., an empty
64 // 'if'.
65 if (RelOffs - getARCMTMacroName().size() > 100)
66 return false;
67
68 SourceLocation AfterMacroSemiLoc = findSemiAfterLocation(AfterMacroLoc, Ctx);
69 return AfterMacroSemiLoc == SemiLoc;
70}
71
72namespace {
73
74/// Returns true if the statement became empty due to previous
75/// transformations.
76class EmptyChecker : public StmtVisitor<EmptyChecker, bool> {
77 ASTContext &Ctx;
78 std::vector<SourceLocation> &MacroLocs;
79
80public:
81 EmptyChecker(ASTContext &ctx, std::vector<SourceLocation> &macroLocs)
82 : Ctx(ctx), MacroLocs(macroLocs) { }
83
84 bool VisitNullStmt(NullStmt *S) {
85 return isEmptyARCMTMacroStatement(S, MacroLocs, Ctx);
86 }
87 bool VisitCompoundStmt(CompoundStmt *S) {
88 if (S->body_empty())
89 return false; // was already empty, not because of transformations.
90 for (auto *I : S->body())
91 if (!Visit(I))
92 return false;
93 return true;
94 }
95 bool VisitIfStmt(IfStmt *S) {
96 if (S->getConditionVariable())
97 return false;
98 Expr *condE = S->getCond();
99 if (!condE)
100 return false;
101 if (hasSideEffects(condE, Ctx))
102 return false;
103 if (!S->getThen() || !Visit(S->getThen()))
104 return false;
105 return !S->getElse() || Visit(S->getElse());
106 }
107 bool VisitWhileStmt(WhileStmt *S) {
108 if (S->getConditionVariable())
109 return false;
110 Expr *condE = S->getCond();
111 if (!condE)
112 return false;
113 if (hasSideEffects(condE, Ctx))
114 return false;
115 if (!S->getBody())
116 return false;
117 return Visit(S->getBody());
118 }
119 bool VisitDoStmt(DoStmt *S) {
120 Expr *condE = S->getCond();
121 if (!condE)
122 return false;
123 if (hasSideEffects(condE, Ctx))
124 return false;
125 if (!S->getBody())
126 return false;
127 return Visit(S->getBody());
128 }
129 bool VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
130 Expr *Exp = S->getCollection();
131 if (!Exp)
132 return false;
133 if (hasSideEffects(Exp, Ctx))
134 return false;
135 if (!S->getBody())
136 return false;
137 return Visit(S->getBody());
138 }
139 bool VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
140 if (!S->getSubStmt())
141 return false;
142 return Visit(S->getSubStmt());
143 }
144};
145
146class EmptyStatementsRemover :
147 public RecursiveASTVisitor<EmptyStatementsRemover> {
148 MigrationPass &Pass;
149
150public:
151 EmptyStatementsRemover(MigrationPass &pass) : Pass(pass) { }
152
153 bool TraverseStmtExpr(StmtExpr *E) {
154 CompoundStmt *S = E->getSubStmt();
156 I = S->body_begin(), E = S->body_end(); I != E; ++I) {
157 if (I != E - 1)
158 check(*I);
159 TraverseStmt(*I);
160 }
161 return true;
162 }
163
164 bool VisitCompoundStmt(CompoundStmt *S) {
165 for (auto *I : S->body())
166 check(I);
167 return true;
168 }
169
170 ASTContext &getContext() { return Pass.Ctx; }
171
172private:
173 void check(Stmt *S) {
174 if (!S) return;
175 if (EmptyChecker(Pass.Ctx, Pass.ARCMTMacroLocs).Visit(S)) {
176 Transaction Trans(Pass.TA);
177 Pass.TA.removeStmt(S);
178 }
179 }
180};
181
182} // anonymous namespace
183
184static bool isBodyEmpty(CompoundStmt *body, ASTContext &Ctx,
185 std::vector<SourceLocation> &MacroLocs) {
186 for (auto *I : body->body())
187 if (!EmptyChecker(Ctx, MacroLocs).Visit(I))
188 return false;
189
190 return true;
191}
192
194 ASTContext &Ctx = pass.Ctx;
195 TransformActions &TA = pass.TA;
197 Selector FinalizeSel =
198 Ctx.Selectors.getNullarySelector(&pass.Ctx.Idents.get("finalize"));
199
201 impl_iterator;
202 for (impl_iterator I = impl_iterator(DC->decls_begin()),
203 E = impl_iterator(DC->decls_end()); I != E; ++I) {
204 ObjCMethodDecl *DeallocM = nullptr;
205 ObjCMethodDecl *FinalizeM = nullptr;
206 for (auto *MD : I->instance_methods()) {
207 if (!MD->hasBody())
208 continue;
209
210 if (MD->getMethodFamily() == OMF_dealloc) {
211 DeallocM = MD;
212 } else if (MD->isInstanceMethod() && MD->getSelector() == FinalizeSel) {
213 FinalizeM = MD;
214 }
215 }
216
217 if (DeallocM) {
218 if (isBodyEmpty(DeallocM->getCompoundBody(), Ctx, pass.ARCMTMacroLocs)) {
219 Transaction Trans(TA);
220 TA.remove(DeallocM->getSourceRange());
221 }
222
223 if (FinalizeM) {
224 Transaction Trans(TA);
225 TA.remove(FinalizeM->getSourceRange());
226 }
227
228 } else if (FinalizeM) {
229 if (isBodyEmpty(FinalizeM->getCompoundBody(), Ctx, pass.ARCMTMacroLocs)) {
230 Transaction Trans(TA);
231 TA.remove(FinalizeM->getSourceRange());
232 } else {
233 Transaction Trans(TA);
234 TA.replaceText(FinalizeM->getSelectorStartLoc(), "finalize", "dealloc");
235 }
236 }
237 }
238}
239
241 EmptyStatementsRemover(pass).TraverseDecl(pass.Ctx.getTranslationUnitDecl());
242
244
245 for (unsigned i = 0, e = pass.ARCMTMacroLocs.size(); i != e; ++i) {
246 Transaction Trans(pass.TA);
247 pass.TA.remove(pass.ARCMTMacroLocs[i]);
248 }
249}
Defines the clang::ASTContext interface.
#define SM(sm)
Definition: Cuda.cpp:82
Defines the SourceManager interface.
static bool isEmptyARCMTMacroStatement(NullStmt *S, std::vector< SourceLocation > &MacroLocs, ASTContext &Ctx)
static bool isBodyEmpty(CompoundStmt *body, ASTContext &Ctx, std::vector< SourceLocation > &MacroLocs)
static void cleanupDeallocOrFinalize(MigrationPass &pass)
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:182
SourceManager & getSourceManager()
Definition: ASTContext.h:705
TranslationUnitDecl * getTranslationUnitDecl() const
Definition: ASTContext.h:1073
IdentifierTable & Idents
Definition: ASTContext.h:644
SelectorTable & Selectors
Definition: ASTContext.h:645
Comparison function object.
CompoundStmt - This represents a group of statements like { stmt stmt }.
Definition: Stmt.h:1611
body_range body()
Definition: Stmt.h:1669
specific_decl_iterator - Iterates over a subrange of declarations stored in a DeclContext,...
Definition: DeclBase.h:2341
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1435
decl_iterator decls_end() const
Definition: DeclBase.h:2323
decl_iterator decls_begin() const
Definition: DeclBase.cpp:1554
DoStmt - This represents a 'do/while' stmt.
Definition: Stmt.h:2730
This represents one expression.
Definition: Expr.h:110
IdentifierInfo & get(StringRef Name)
Return the identifier token info for the specified named identifier.
IfStmt - This represents an if/then/else.
Definition: Stmt.h:2143
NullStmt - This is the null statement ";": C99 6.8.3p3.
Definition: Stmt.h:1574
Represents Objective-C's @autoreleasepool Statement.
Definition: StmtObjC.h:394
Represents Objective-C's collection statement.
Definition: StmtObjC.h:23
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:140
CompoundStmt * getCompoundBody()
Definition: DeclObjC.h:530
SourceLocation getSelectorStartLoc() const
Definition: DeclObjC.h:288
SourceRange getSourceRange() const override LLVM_READONLY
Source range that this declaration covers.
Definition: DeclObjC.h:284
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
bool TraverseStmt(Stmt *S, DataRecursionQueue *Queue=nullptr)
Recursively visit a statement or expression, by dispatching to Traverse*() based on the argument's dy...
Selector getNullarySelector(const IdentifierInfo *ID)
Smart pointer class that efficiently represents Objective-C method names.
Encodes a location in the source.
SourceLocation getLocWithOffset(IntTy Offset) const
Return a source location with the specified offset from this SourceLocation.
This class handles loading and caching of source files into memory.
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:4383
CompoundStmt * getSubStmt()
Definition: Expr.h:4400
RetTy Visit(PTR(Stmt) S, ParamTys... P)
Definition: StmtVisitor.h:44
StmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:185
Stmt - This represents one statement.
Definition: Stmt.h:84
WhileStmt - This represents a 'while' stmt.
Definition: Stmt.h:2589
std::vector< SourceLocation > & ARCMTMacroLocs
Definition: Internals.h:154
TransformActions & TA
Definition: Internals.h:152
void remove(SourceRange range)
void replaceText(SourceLocation loc, StringRef text, StringRef replacementText)
bool hasSideEffects(Expr *E, ASTContext &Ctx)
Definition: Transforms.cpp:166
void removeEmptyStatementsAndDeallocFinalize(MigrationPass &pass)
SourceLocation findSemiAfterLocation(SourceLocation loc, ASTContext &Ctx, bool IsDecl=false)
'Loc' is the end of a statement range.
Definition: Transforms.cpp:128
static StringRef getARCMTMacroName()
Definition: Internals.h:172
The JSON file list parser is used to communicate input to InstallAPI.