clang-tools  14.0.0git
LoopConvertCheck.cpp
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1 //===--- LoopConvertCheck.cpp - clang-tidy---------------------------------===//
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 #include "LoopConvertCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Basic/LLVM.h"
13 #include "clang/Basic/LangOptions.h"
14 #include "clang/Basic/SourceLocation.h"
15 #include "clang/Basic/SourceManager.h"
16 #include "clang/Lex/Lexer.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/ADT/StringSwitch.h"
21 #include "llvm/Support/Casting.h"
22 #include "llvm/Support/raw_ostream.h"
23 #include <cassert>
24 #include <cstring>
25 #include <utility>
26 
27 using namespace clang::ast_matchers;
28 using namespace llvm;
29 
30 namespace clang {
31 namespace tidy {
32 
33 template <> struct OptionEnumMapping<modernize::Confidence::Level> {
34  static llvm::ArrayRef<std::pair<modernize::Confidence::Level, StringRef>>
36  static constexpr std::pair<modernize::Confidence::Level, StringRef>
37  Mapping[] = {{modernize::Confidence::CL_Reasonable, "reasonable"},
38  {modernize::Confidence::CL_Safe, "safe"},
39  {modernize::Confidence::CL_Risky, "risky"}};
40  return makeArrayRef(Mapping);
41  }
42 };
43 
44 template <> struct OptionEnumMapping<modernize::VariableNamer::NamingStyle> {
45  static llvm::ArrayRef<
46  std::pair<modernize::VariableNamer::NamingStyle, StringRef>>
48  static constexpr std::pair<modernize::VariableNamer::NamingStyle, StringRef>
49  Mapping[] = {{modernize::VariableNamer::NS_CamelCase, "CamelCase"},
50  {modernize::VariableNamer::NS_CamelBack, "camelBack"},
51  {modernize::VariableNamer::NS_LowerCase, "lower_case"},
52  {modernize::VariableNamer::NS_UpperCase, "UPPER_CASE"}};
53  return makeArrayRef(Mapping);
54  }
55 };
56 
57 namespace modernize {
58 
59 static const char LoopNameArray[] = "forLoopArray";
60 static const char LoopNameIterator[] = "forLoopIterator";
61 static const char LoopNameReverseIterator[] = "forLoopReverseIterator";
62 static const char LoopNamePseudoArray[] = "forLoopPseudoArray";
63 static const char ConditionBoundName[] = "conditionBound";
64 static const char InitVarName[] = "initVar";
65 static const char BeginCallName[] = "beginCall";
66 static const char EndCallName[] = "endCall";
67 static const char EndVarName[] = "endVar";
68 static const char DerefByValueResultName[] = "derefByValueResult";
69 static const char DerefByRefResultName[] = "derefByRefResult";
70 
71 static const StatementMatcher integerComparisonMatcher() {
72  return expr(ignoringParenImpCasts(
73  declRefExpr(to(varDecl(equalsBoundNode(InitVarName))))));
74 }
75 
76 static const DeclarationMatcher initToZeroMatcher() {
77  return varDecl(
78  hasInitializer(ignoringParenImpCasts(integerLiteral(equals(0)))))
79  .bind(InitVarName);
80 }
81 
82 static const StatementMatcher incrementVarMatcher() {
83  return declRefExpr(to(varDecl(equalsBoundNode(InitVarName))));
84 }
85 
86 static StatementMatcher
87 arrayConditionMatcher(internal::Matcher<Expr> LimitExpr) {
88  return binaryOperator(
89  anyOf(allOf(hasOperatorName("<"), hasLHS(integerComparisonMatcher()),
90  hasRHS(LimitExpr)),
91  allOf(hasOperatorName(">"), hasLHS(LimitExpr),
92  hasRHS(integerComparisonMatcher())),
93  allOf(hasOperatorName("!="),
94  hasOperands(integerComparisonMatcher(), LimitExpr))));
95 }
96 
97 /// The matcher for loops over arrays.
98 /// \code
99 /// for (int i = 0; i < 3 + 2; ++i) { ... }
100 /// \endcode
101 /// The following string identifiers are bound to these parts of the AST:
102 /// ConditionBoundName: '3 + 2' (as an Expr)
103 /// InitVarName: 'i' (as a VarDecl)
104 /// LoopName: The entire for loop (as a ForStmt)
105 ///
106 /// Client code will need to make sure that:
107 /// - The index variable is only used as an array index.
108 /// - All arrays indexed by the loop are the same.
109 StatementMatcher makeArrayLoopMatcher() {
110  StatementMatcher ArrayBoundMatcher =
111  expr(hasType(isInteger())).bind(ConditionBoundName);
112 
113  return forStmt(unless(isInTemplateInstantiation()),
114  hasLoopInit(declStmt(hasSingleDecl(initToZeroMatcher()))),
115  hasCondition(arrayConditionMatcher(ArrayBoundMatcher)),
116  hasIncrement(
117  unaryOperator(hasOperatorName("++"),
118  hasUnaryOperand(incrementVarMatcher()))))
119  .bind(LoopNameArray);
120 }
121 
122 /// The matcher used for iterator-based for loops.
123 ///
124 /// This matcher is more flexible than array-based loops. It will match
125 /// catch loops of the following textual forms (regardless of whether the
126 /// iterator type is actually a pointer type or a class type):
127 ///
128 /// \code
129 /// for (containerType::iterator it = container.begin(),
130 /// e = createIterator(); it != e; ++it) { ... }
131 /// for (containerType::iterator it = container.begin();
132 /// it != anotherContainer.end(); ++it) { ... }
133 /// \endcode
134 /// The following string identifiers are bound to the parts of the AST:
135 /// InitVarName: 'it' (as a VarDecl)
136 /// LoopName: The entire for loop (as a ForStmt)
137 /// In the first example only:
138 /// EndVarName: 'e' (as a VarDecl)
139 /// In the second example only:
140 /// EndCallName: 'container.end()' (as a CXXMemberCallExpr)
141 ///
142 /// Client code will need to make sure that:
143 /// - The two containers on which 'begin' and 'end' are called are the same.
144 StatementMatcher makeIteratorLoopMatcher(bool IsReverse) {
145 
146  auto BeginNameMatcher = IsReverse ? hasAnyName("rbegin", "crbegin")
147  : hasAnyName("begin", "cbegin");
148 
149  auto EndNameMatcher =
150  IsReverse ? hasAnyName("rend", "crend") : hasAnyName("end", "cend");
151 
152  StatementMatcher BeginCallMatcher =
153  cxxMemberCallExpr(argumentCountIs(0),
154  callee(cxxMethodDecl(BeginNameMatcher)))
155  .bind(BeginCallName);
156 
157  DeclarationMatcher InitDeclMatcher =
158  varDecl(hasInitializer(anyOf(ignoringParenImpCasts(BeginCallMatcher),
159  materializeTemporaryExpr(
160  ignoringParenImpCasts(BeginCallMatcher)),
161  hasDescendant(BeginCallMatcher))))
162  .bind(InitVarName);
163 
164  DeclarationMatcher EndDeclMatcher =
165  varDecl(hasInitializer(anything())).bind(EndVarName);
166 
167  StatementMatcher EndCallMatcher = cxxMemberCallExpr(
168  argumentCountIs(0), callee(cxxMethodDecl(EndNameMatcher)));
169 
170  StatementMatcher IteratorBoundMatcher =
171  expr(anyOf(ignoringParenImpCasts(
172  declRefExpr(to(varDecl(equalsBoundNode(EndVarName))))),
173  ignoringParenImpCasts(expr(EndCallMatcher).bind(EndCallName)),
174  materializeTemporaryExpr(ignoringParenImpCasts(
175  expr(EndCallMatcher).bind(EndCallName)))));
176 
177  StatementMatcher IteratorComparisonMatcher = expr(ignoringParenImpCasts(
178  declRefExpr(to(varDecl(equalsBoundNode(InitVarName))))));
179 
180  // This matcher tests that a declaration is a CXXRecordDecl that has an
181  // overloaded operator*(). If the operator*() returns by value instead of by
182  // reference then the return type is tagged with DerefByValueResultName.
183  internal::Matcher<VarDecl> TestDerefReturnsByValue =
184  hasType(hasUnqualifiedDesugaredType(
185  recordType(hasDeclaration(cxxRecordDecl(hasMethod(cxxMethodDecl(
186  hasOverloadedOperatorName("*"),
187  anyOf(
188  // Tag the return type if it's by value.
189  returns(qualType(unless(hasCanonicalType(referenceType())))
190  .bind(DerefByValueResultName)),
191  returns(
192  // Skip loops where the iterator's operator* returns an
193  // rvalue reference. This is just weird.
194  qualType(unless(hasCanonicalType(rValueReferenceType())))
195  .bind(DerefByRefResultName))))))))));
196 
197  return forStmt(
198  unless(isInTemplateInstantiation()),
199  hasLoopInit(anyOf(declStmt(declCountIs(2),
200  containsDeclaration(0, InitDeclMatcher),
201  containsDeclaration(1, EndDeclMatcher)),
202  declStmt(hasSingleDecl(InitDeclMatcher)))),
203  hasCondition(ignoringImplicit(binaryOperation(
204  hasOperatorName("!="), hasOperands(IteratorComparisonMatcher,
205  IteratorBoundMatcher)))),
206  hasIncrement(anyOf(
207  unaryOperator(hasOperatorName("++"),
208  hasUnaryOperand(declRefExpr(
209  to(varDecl(equalsBoundNode(InitVarName)))))),
210  cxxOperatorCallExpr(
211  hasOverloadedOperatorName("++"),
212  hasArgument(0, declRefExpr(to(
213  varDecl(equalsBoundNode(InitVarName),
214  TestDerefReturnsByValue))))))))
215  .bind(IsReverse ? LoopNameReverseIterator : LoopNameIterator);
216 }
217 
218 /// The matcher used for array-like containers (pseudoarrays).
219 ///
220 /// This matcher is more flexible than array-based loops. It will match
221 /// loops of the following textual forms (regardless of whether the
222 /// iterator type is actually a pointer type or a class type):
223 ///
224 /// \code
225 /// for (int i = 0, j = container.size(); i < j; ++i) { ... }
226 /// for (int i = 0; i < container.size(); ++i) { ... }
227 /// \endcode
228 /// The following string identifiers are bound to the parts of the AST:
229 /// InitVarName: 'i' (as a VarDecl)
230 /// LoopName: The entire for loop (as a ForStmt)
231 /// In the first example only:
232 /// EndVarName: 'j' (as a VarDecl)
233 /// In the second example only:
234 /// EndCallName: 'container.size()' (as a CXXMemberCallExpr)
235 ///
236 /// Client code will need to make sure that:
237 /// - The containers on which 'size()' is called is the container indexed.
238 /// - The index variable is only used in overloaded operator[] or
239 /// container.at().
240 /// - The container's iterators would not be invalidated during the loop.
241 StatementMatcher makePseudoArrayLoopMatcher() {
242  // Test that the incoming type has a record declaration that has methods
243  // called 'begin' and 'end'. If the incoming type is const, then make sure
244  // these methods are also marked const.
245  //
246  // FIXME: To be completely thorough this matcher should also ensure the
247  // return type of begin/end is an iterator that dereferences to the same as
248  // what operator[] or at() returns. Such a test isn't likely to fail except
249  // for pathological cases.
250  //
251  // FIXME: Also, a record doesn't necessarily need begin() and end(). Free
252  // functions called begin() and end() taking the container as an argument
253  // are also allowed.
254  TypeMatcher RecordWithBeginEnd = qualType(anyOf(
255  qualType(
256  isConstQualified(),
257  hasUnqualifiedDesugaredType(recordType(hasDeclaration(cxxRecordDecl(
258  hasMethod(cxxMethodDecl(hasName("begin"), isConst())),
259  hasMethod(cxxMethodDecl(hasName("end"),
260  isConst())))) // hasDeclaration
261  ))), // qualType
262  qualType(unless(isConstQualified()),
263  hasUnqualifiedDesugaredType(recordType(hasDeclaration(
264  cxxRecordDecl(hasMethod(hasName("begin")),
265  hasMethod(hasName("end"))))))) // qualType
266  ));
267 
268  StatementMatcher SizeCallMatcher = cxxMemberCallExpr(
269  argumentCountIs(0), callee(cxxMethodDecl(hasAnyName("size", "length"))),
270  on(anyOf(hasType(pointsTo(RecordWithBeginEnd)),
271  hasType(RecordWithBeginEnd))));
272 
273  StatementMatcher EndInitMatcher =
274  expr(anyOf(ignoringParenImpCasts(expr(SizeCallMatcher).bind(EndCallName)),
275  explicitCastExpr(hasSourceExpression(ignoringParenImpCasts(
276  expr(SizeCallMatcher).bind(EndCallName))))));
277 
278  DeclarationMatcher EndDeclMatcher =
279  varDecl(hasInitializer(EndInitMatcher)).bind(EndVarName);
280 
281  StatementMatcher IndexBoundMatcher =
282  expr(anyOf(ignoringParenImpCasts(
283  declRefExpr(to(varDecl(equalsBoundNode(EndVarName))))),
284  EndInitMatcher));
285 
286  return forStmt(unless(isInTemplateInstantiation()),
287  hasLoopInit(
288  anyOf(declStmt(declCountIs(2),
289  containsDeclaration(0, initToZeroMatcher()),
290  containsDeclaration(1, EndDeclMatcher)),
291  declStmt(hasSingleDecl(initToZeroMatcher())))),
292  hasCondition(arrayConditionMatcher(IndexBoundMatcher)),
293  hasIncrement(
294  unaryOperator(hasOperatorName("++"),
295  hasUnaryOperand(incrementVarMatcher()))))
296  .bind(LoopNamePseudoArray);
297 }
298 
299 /// Determine whether Init appears to be an initializing an iterator.
300 ///
301 /// If it is, returns the object whose begin() or end() method is called, and
302 /// the output parameter isArrow is set to indicate whether the initialization
303 /// is called via . or ->.
304 static const Expr *getContainerFromBeginEndCall(const Expr *Init, bool IsBegin,
305  bool *IsArrow, bool IsReverse) {
306  // FIXME: Maybe allow declaration/initialization outside of the for loop.
307  const auto *TheCall = dyn_cast_or_null<CXXMemberCallExpr>(
309  if (!TheCall || TheCall->getNumArgs() != 0)
310  return nullptr;
311 
312  const auto *Member = dyn_cast<MemberExpr>(TheCall->getCallee());
313  if (!Member)
314  return nullptr;
315  StringRef Name = Member->getMemberDecl()->getName();
316  if (!Name.consume_back(IsBegin ? "begin" : "end"))
317  return nullptr;
318  if (IsReverse && !Name.consume_back("r"))
319  return nullptr;
320  if (!Name.empty() && !Name.equals("c"))
321  return nullptr;
322 
323  const Expr *SourceExpr = Member->getBase();
324  if (!SourceExpr)
325  return nullptr;
326 
327  *IsArrow = Member->isArrow();
328  return SourceExpr;
329 }
330 
331 /// Determines the container whose begin() and end() functions are called
332 /// for an iterator-based loop.
333 ///
334 /// BeginExpr must be a member call to a function named "begin()", and EndExpr
335 /// must be a member.
336 static const Expr *findContainer(ASTContext *Context, const Expr *BeginExpr,
337  const Expr *EndExpr,
338  bool *ContainerNeedsDereference,
339  bool IsReverse) {
340  // Now that we know the loop variable and test expression, make sure they are
341  // valid.
342  bool BeginIsArrow = false;
343  bool EndIsArrow = false;
344  const Expr *BeginContainerExpr = getContainerFromBeginEndCall(
345  BeginExpr, /*IsBegin=*/true, &BeginIsArrow, IsReverse);
346  if (!BeginContainerExpr)
347  return nullptr;
348 
349  const Expr *EndContainerExpr = getContainerFromBeginEndCall(
350  EndExpr, /*IsBegin=*/false, &EndIsArrow, IsReverse);
351  // Disallow loops that try evil things like this (note the dot and arrow):
352  // for (IteratorType It = Obj.begin(), E = Obj->end(); It != E; ++It) { }
353  if (!EndContainerExpr || BeginIsArrow != EndIsArrow ||
354  !areSameExpr(Context, EndContainerExpr, BeginContainerExpr))
355  return nullptr;
356 
357  *ContainerNeedsDereference = BeginIsArrow;
358  return BeginContainerExpr;
359 }
360 
361 /// Obtain the original source code text from a SourceRange.
362 static StringRef getStringFromRange(SourceManager &SourceMgr,
363  const LangOptions &LangOpts,
364  SourceRange Range) {
365  if (SourceMgr.getFileID(Range.getBegin()) !=
366  SourceMgr.getFileID(Range.getEnd())) {
367  return StringRef(); // Empty string.
368  }
369 
370  return Lexer::getSourceText(CharSourceRange(Range, true), SourceMgr,
371  LangOpts);
372 }
373 
374 /// If the given expression is actually a DeclRefExpr or a MemberExpr,
375 /// find and return the underlying ValueDecl; otherwise, return NULL.
376 static const ValueDecl *getReferencedVariable(const Expr *E) {
377  if (const DeclRefExpr *DRE = getDeclRef(E))
378  return dyn_cast<VarDecl>(DRE->getDecl());
379  if (const auto *Mem = dyn_cast<MemberExpr>(E->IgnoreParenImpCasts()))
380  return dyn_cast<FieldDecl>(Mem->getMemberDecl());
381  return nullptr;
382 }
383 
384 /// Returns true when the given expression is a member expression
385 /// whose base is `this` (implicitly or not).
386 static bool isDirectMemberExpr(const Expr *E) {
387  if (const auto *Member = dyn_cast<MemberExpr>(E->IgnoreParenImpCasts()))
388  return isa<CXXThisExpr>(Member->getBase()->IgnoreParenImpCasts());
389  return false;
390 }
391 
392 /// Given an expression that represents an usage of an element from the
393 /// containter that we are iterating over, returns false when it can be
394 /// guaranteed this element cannot be modified as a result of this usage.
395 static bool canBeModified(ASTContext *Context, const Expr *E) {
396  if (E->getType().isConstQualified())
397  return false;
398  auto Parents = Context->getParents(*E);
399  if (Parents.size() != 1)
400  return true;
401  if (const auto *Cast = Parents[0].get<ImplicitCastExpr>()) {
402  if ((Cast->getCastKind() == CK_NoOp &&
403  Cast->getType() == E->getType().withConst()) ||
404  (Cast->getCastKind() == CK_LValueToRValue &&
405  !Cast->getType().isNull() && Cast->getType()->isFundamentalType()))
406  return false;
407  }
408  // FIXME: Make this function more generic.
409  return true;
410 }
411 
412 /// Returns true when it can be guaranteed that the elements of the
413 /// container are not being modified.
414 static bool usagesAreConst(ASTContext *Context, const UsageResult &Usages) {
415  for (const Usage &U : Usages) {
416  // Lambda captures are just redeclarations (VarDecl) of the same variable,
417  // not expressions. If we want to know if a variable that is captured by
418  // reference can be modified in an usage inside the lambda's body, we need
419  // to find the expression corresponding to that particular usage, later in
420  // this loop.
421  if (U.Kind != Usage::UK_CaptureByCopy && U.Kind != Usage::UK_CaptureByRef &&
422  canBeModified(Context, U.Expression))
423  return false;
424  }
425  return true;
426 }
427 
428 /// Returns true if the elements of the container are never accessed
429 /// by reference.
430 static bool usagesReturnRValues(const UsageResult &Usages) {
431  for (const auto &U : Usages) {
432  if (U.Expression && !U.Expression->isPRValue())
433  return false;
434  }
435  return true;
436 }
437 
438 /// Returns true if the container is const-qualified.
439 static bool containerIsConst(const Expr *ContainerExpr, bool Dereference) {
440  if (const auto *VDec = getReferencedVariable(ContainerExpr)) {
441  QualType CType = VDec->getType();
442  if (Dereference) {
443  if (!CType->isPointerType())
444  return false;
445  CType = CType->getPointeeType();
446  }
447  // If VDec is a reference to a container, Dereference is false,
448  // but we still need to check the const-ness of the underlying container
449  // type.
450  CType = CType.getNonReferenceType();
451  return CType.isConstQualified();
452  }
453  return false;
454 }
455 
456 LoopConvertCheck::RangeDescriptor::RangeDescriptor()
457  : ContainerNeedsDereference(false), DerefByConstRef(false),
458  DerefByValue(false), NeedsReverseCall(false) {}
459 
460 LoopConvertCheck::LoopConvertCheck(StringRef Name, ClangTidyContext *Context)
461  : ClangTidyCheck(Name, Context), TUInfo(new TUTrackingInfo),
462  MaxCopySize(Options.get("MaxCopySize", 16ULL)),
463  MinConfidence(Options.get("MinConfidence", Confidence::CL_Reasonable)),
464  NamingStyle(Options.get("NamingStyle", VariableNamer::NS_CamelCase)),
465  Inserter(Options.getLocalOrGlobal("IncludeStyle",
466  utils::IncludeSorter::IS_LLVM)),
467  UseCxx20IfAvailable(Options.get("UseCxx20ReverseRanges", true)),
468  ReverseFunction(Options.get("MakeReverseRangeFunction", "")),
469  ReverseHeader(Options.get("MakeReverseRangeHeader", "")) {
470 
471  if (ReverseFunction.empty() && !ReverseHeader.empty()) {
473  "modernize-loop-convert: 'MakeReverseRangeHeader' is set but "
474  "'MakeReverseRangeFunction' is not, disabling reverse loop "
475  "transformation");
476  UseReverseRanges = false;
477  } else if (ReverseFunction.empty()) {
478  UseReverseRanges = UseCxx20IfAvailable && getLangOpts().CPlusPlus20;
479  } else {
480  UseReverseRanges = true;
481  }
482 }
483 
485  Options.store(Opts, "MaxCopySize", MaxCopySize);
486  Options.store(Opts, "MinConfidence", MinConfidence);
487  Options.store(Opts, "NamingStyle", NamingStyle);
488  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
489  Options.store(Opts, "UseCxx20ReverseRanges", UseCxx20IfAvailable);
490  Options.store(Opts, "MakeReverseRangeFunction", ReverseFunction);
491  Options.store(Opts, "MakeReverseRangeHeader", ReverseHeader);
492 }
493 
494 void LoopConvertCheck::registerPPCallbacks(const SourceManager &SM,
495  Preprocessor *PP,
496  Preprocessor *ModuleExpanderPP) {
497  Inserter.registerPreprocessor(PP);
498 }
499 
500 void LoopConvertCheck::registerMatchers(MatchFinder *Finder) {
501  Finder->addMatcher(traverse(TK_AsIs, makeArrayLoopMatcher()), this);
502  Finder->addMatcher(traverse(TK_AsIs, makeIteratorLoopMatcher(false)), this);
503  Finder->addMatcher(traverse(TK_AsIs, makePseudoArrayLoopMatcher()), this);
504  if (UseReverseRanges)
505  Finder->addMatcher(traverse(TK_AsIs, makeIteratorLoopMatcher(true)), this);
506 }
507 
508 /// Given the range of a single declaration, such as:
509 /// \code
510 /// unsigned &ThisIsADeclarationThatCanSpanSeveralLinesOfCode =
511 /// InitializationValues[I];
512 /// next_instruction;
513 /// \endcode
514 /// Finds the range that has to be erased to remove this declaration without
515 /// leaving empty lines, by extending the range until the beginning of the
516 /// next instruction.
517 ///
518 /// We need to delete a potential newline after the deleted alias, as
519 /// clang-format will leave empty lines untouched. For all other formatting we
520 /// rely on clang-format to fix it.
521 void LoopConvertCheck::getAliasRange(SourceManager &SM, SourceRange &Range) {
522  bool Invalid = false;
523  const char *TextAfter =
524  SM.getCharacterData(Range.getEnd().getLocWithOffset(1), &Invalid);
525  if (Invalid)
526  return;
527  unsigned Offset = std::strspn(TextAfter, " \t\r\n");
528  Range =
529  SourceRange(Range.getBegin(), Range.getEnd().getLocWithOffset(Offset));
530 }
531 
532 /// Computes the changes needed to convert a given for loop, and
533 /// applies them.
534 void LoopConvertCheck::doConversion(
535  ASTContext *Context, const VarDecl *IndexVar,
536  const ValueDecl *MaybeContainer, const UsageResult &Usages,
537  const DeclStmt *AliasDecl, bool AliasUseRequired, bool AliasFromForInit,
538  const ForStmt *Loop, RangeDescriptor Descriptor) {
539  std::string VarName;
540  bool VarNameFromAlias = (Usages.size() == 1) && AliasDecl;
541  bool AliasVarIsRef = false;
542  bool CanCopy = true;
543  std::vector<FixItHint> FixIts;
544  if (VarNameFromAlias) {
545  const auto *AliasVar = cast<VarDecl>(AliasDecl->getSingleDecl());
546  VarName = AliasVar->getName().str();
547 
548  // Use the type of the alias if it's not the same
549  QualType AliasVarType = AliasVar->getType();
550  assert(!AliasVarType.isNull() && "Type in VarDecl is null");
551  if (AliasVarType->isReferenceType()) {
552  AliasVarType = AliasVarType.getNonReferenceType();
553  AliasVarIsRef = true;
554  }
555  if (Descriptor.ElemType.isNull() ||
556  !Context->hasSameUnqualifiedType(AliasVarType, Descriptor.ElemType))
557  Descriptor.ElemType = AliasVarType;
558 
559  // We keep along the entire DeclStmt to keep the correct range here.
560  SourceRange ReplaceRange = AliasDecl->getSourceRange();
561 
562  std::string ReplacementText;
563  if (AliasUseRequired) {
564  ReplacementText = VarName;
565  } else if (AliasFromForInit) {
566  // FIXME: Clang includes the location of the ';' but only for DeclStmt's
567  // in a for loop's init clause. Need to put this ';' back while removing
568  // the declaration of the alias variable. This is probably a bug.
569  ReplacementText = ";";
570  } else {
571  // Avoid leaving empty lines or trailing whitespaces.
572  getAliasRange(Context->getSourceManager(), ReplaceRange);
573  }
574 
575  FixIts.push_back(FixItHint::CreateReplacement(
576  CharSourceRange::getTokenRange(ReplaceRange), ReplacementText));
577  // No further replacements are made to the loop, since the iterator or index
578  // was used exactly once - in the initialization of AliasVar.
579  } else {
580  VariableNamer Namer(&TUInfo->getGeneratedDecls(),
581  &TUInfo->getParentFinder().getStmtToParentStmtMap(),
582  Loop, IndexVar, MaybeContainer, Context, NamingStyle);
583  VarName = Namer.createIndexName();
584  // First, replace all usages of the array subscript expression with our new
585  // variable.
586  for (const auto &Usage : Usages) {
587  std::string ReplaceText;
588  SourceRange Range = Usage.Range;
589  if (Usage.Expression) {
590  // If this is an access to a member through the arrow operator, after
591  // the replacement it must be accessed through the '.' operator.
592  ReplaceText = Usage.Kind == Usage::UK_MemberThroughArrow ? VarName + "."
593  : VarName;
594  auto Parents = Context->getParents(*Usage.Expression);
595  if (Parents.size() == 1) {
596  if (const auto *Paren = Parents[0].get<ParenExpr>()) {
597  // Usage.Expression will be replaced with the new index variable,
598  // and parenthesis around a simple DeclRefExpr can always be
599  // removed.
600  Range = Paren->getSourceRange();
601  } else if (const auto *UOP = Parents[0].get<UnaryOperator>()) {
602  // If we are taking the address of the loop variable, then we must
603  // not use a copy, as it would mean taking the address of the loop's
604  // local index instead.
605  // FIXME: This won't catch cases where the address is taken outside
606  // of the loop's body (for instance, in a function that got the
607  // loop's index as a const reference parameter), or where we take
608  // the address of a member (like "&Arr[i].A.B.C").
609  if (UOP->getOpcode() == UO_AddrOf)
610  CanCopy = false;
611  }
612  }
613  } else {
614  // The Usage expression is only null in case of lambda captures (which
615  // are VarDecl). If the index is captured by value, add '&' to capture
616  // by reference instead.
617  ReplaceText =
618  Usage.Kind == Usage::UK_CaptureByCopy ? "&" + VarName : VarName;
619  }
620  TUInfo->getReplacedVars().insert(std::make_pair(Loop, IndexVar));
621  FixIts.push_back(FixItHint::CreateReplacement(
622  CharSourceRange::getTokenRange(Range), ReplaceText));
623  }
624  }
625 
626  // Now, we need to construct the new range expression.
627  SourceRange ParenRange(Loop->getLParenLoc(), Loop->getRParenLoc());
628 
629  QualType Type = Context->getAutoDeductType();
630  if (!Descriptor.ElemType.isNull() && Descriptor.ElemType->isFundamentalType())
631  Type = Descriptor.ElemType.getUnqualifiedType();
632  Type = Type.getDesugaredType(*Context);
633 
634  // If the new variable name is from the aliased variable, then the reference
635  // type for the new variable should only be used if the aliased variable was
636  // declared as a reference.
637  bool IsCheapToCopy =
638  !Descriptor.ElemType.isNull() &&
639  Descriptor.ElemType.isTriviallyCopyableType(*Context) &&
640  // TypeInfo::Width is in bits.
641  Context->getTypeInfo(Descriptor.ElemType).Width <= 8 * MaxCopySize;
642  bool UseCopy = CanCopy && ((VarNameFromAlias && !AliasVarIsRef) ||
643  (Descriptor.DerefByConstRef && IsCheapToCopy));
644 
645  if (!UseCopy) {
646  if (Descriptor.DerefByConstRef) {
647  Type = Context->getLValueReferenceType(Context->getConstType(Type));
648  } else if (Descriptor.DerefByValue) {
649  if (!IsCheapToCopy)
650  Type = Context->getRValueReferenceType(Type);
651  } else {
652  Type = Context->getLValueReferenceType(Type);
653  }
654  }
655 
656  SmallString<128> Range;
657  llvm::raw_svector_ostream Output(Range);
658  Output << '(';
659  Type.print(Output, getLangOpts());
660  Output << ' ' << VarName << " : ";
661  if (Descriptor.NeedsReverseCall)
662  Output << getReverseFunction() << '(';
663  if (Descriptor.ContainerNeedsDereference)
664  Output << '*';
665  Output << Descriptor.ContainerString;
666  if (Descriptor.NeedsReverseCall)
667  Output << "))";
668  else
669  Output << ')';
670  FixIts.push_back(FixItHint::CreateReplacement(
671  CharSourceRange::getTokenRange(ParenRange), Range));
672 
673  if (Descriptor.NeedsReverseCall && !getReverseHeader().empty()) {
674  if (Optional<FixItHint> Insertion = Inserter.createIncludeInsertion(
675  Context->getSourceManager().getFileID(Loop->getBeginLoc()),
676  getReverseHeader()))
677  FixIts.push_back(*Insertion);
678  }
679  diag(Loop->getForLoc(), "use range-based for loop instead") << FixIts;
680  TUInfo->getGeneratedDecls().insert(make_pair(Loop, VarName));
681 }
682 
683 /// Returns a string which refers to the container iterated over.
684 StringRef LoopConvertCheck::getContainerString(ASTContext *Context,
685  const ForStmt *Loop,
686  const Expr *ContainerExpr) {
687  StringRef ContainerString;
688  ContainerExpr = ContainerExpr->IgnoreParenImpCasts();
689  if (isa<CXXThisExpr>(ContainerExpr)) {
690  ContainerString = "this";
691  } else {
692  // For CXXOperatorCallExpr such as vector_ptr->size() we want the class
693  // object vector_ptr, but for vector[2] we need the whole expression.
694  if (const auto* E = dyn_cast<CXXOperatorCallExpr>(ContainerExpr))
695  if (E->getOperator() != OO_Subscript)
696  ContainerExpr = E->getArg(0);
697  ContainerString =
698  getStringFromRange(Context->getSourceManager(), Context->getLangOpts(),
699  ContainerExpr->getSourceRange());
700  }
701 
702  return ContainerString;
703 }
704 
705 /// Determines what kind of 'auto' must be used after converting a for
706 /// loop that iterates over an array or pseudoarray.
707 void LoopConvertCheck::getArrayLoopQualifiers(ASTContext *Context,
708  const BoundNodes &Nodes,
709  const Expr *ContainerExpr,
710  const UsageResult &Usages,
711  RangeDescriptor &Descriptor) {
712  // On arrays and pseudoarrays, we must figure out the qualifiers from the
713  // usages.
714  if (usagesAreConst(Context, Usages) ||
715  containerIsConst(ContainerExpr, Descriptor.ContainerNeedsDereference)) {
716  Descriptor.DerefByConstRef = true;
717  }
718  if (usagesReturnRValues(Usages)) {
719  // If the index usages (dereference, subscript, at, ...) return rvalues,
720  // then we should not use a reference, because we need to keep the code
721  // correct if it mutates the returned objects.
722  Descriptor.DerefByValue = true;
723  }
724  // Try to find the type of the elements on the container, to check if
725  // they are trivially copyable.
726  for (const Usage &U : Usages) {
727  if (!U.Expression || U.Expression->getType().isNull())
728  continue;
729  QualType Type = U.Expression->getType().getCanonicalType();
730  if (U.Kind == Usage::UK_MemberThroughArrow) {
731  if (!Type->isPointerType()) {
732  continue;
733  }
734  Type = Type->getPointeeType();
735  }
736  Descriptor.ElemType = Type;
737  }
738 }
739 
740 /// Determines what kind of 'auto' must be used after converting an
741 /// iterator based for loop.
742 void LoopConvertCheck::getIteratorLoopQualifiers(ASTContext *Context,
743  const BoundNodes &Nodes,
744  RangeDescriptor &Descriptor) {
745  // The matchers for iterator loops provide bound nodes to obtain this
746  // information.
747  const auto *InitVar = Nodes.getNodeAs<VarDecl>(InitVarName);
748  QualType CanonicalInitVarType = InitVar->getType().getCanonicalType();
749  const auto *DerefByValueType =
750  Nodes.getNodeAs<QualType>(DerefByValueResultName);
751  Descriptor.DerefByValue = DerefByValueType;
752 
753  if (Descriptor.DerefByValue) {
754  // If the dereference operator returns by value then test for the
755  // canonical const qualification of the init variable type.
756  Descriptor.DerefByConstRef = CanonicalInitVarType.isConstQualified();
757  Descriptor.ElemType = *DerefByValueType;
758  } else {
759  if (const auto *DerefType =
760  Nodes.getNodeAs<QualType>(DerefByRefResultName)) {
761  // A node will only be bound with DerefByRefResultName if we're dealing
762  // with a user-defined iterator type. Test the const qualification of
763  // the reference type.
764  auto ValueType = DerefType->getNonReferenceType();
765 
766  Descriptor.DerefByConstRef = ValueType.isConstQualified();
767  Descriptor.ElemType = ValueType;
768  } else {
769  // By nature of the matcher this case is triggered only for built-in
770  // iterator types (i.e. pointers).
771  assert(isa<PointerType>(CanonicalInitVarType) &&
772  "Non-class iterator type is not a pointer type");
773 
774  // We test for const qualification of the pointed-at type.
775  Descriptor.DerefByConstRef =
776  CanonicalInitVarType->getPointeeType().isConstQualified();
777  Descriptor.ElemType = CanonicalInitVarType->getPointeeType();
778  }
779  }
780 }
781 
782 /// Determines the parameters needed to build the range replacement.
783 void LoopConvertCheck::determineRangeDescriptor(
784  ASTContext *Context, const BoundNodes &Nodes, const ForStmt *Loop,
785  LoopFixerKind FixerKind, const Expr *ContainerExpr,
786  const UsageResult &Usages, RangeDescriptor &Descriptor) {
787  Descriptor.ContainerString =
788  std::string(getContainerString(Context, Loop, ContainerExpr));
789  Descriptor.NeedsReverseCall = (FixerKind == LFK_ReverseIterator);
790 
791  if (FixerKind == LFK_Iterator || FixerKind == LFK_ReverseIterator)
792  getIteratorLoopQualifiers(Context, Nodes, Descriptor);
793  else
794  getArrayLoopQualifiers(Context, Nodes, ContainerExpr, Usages, Descriptor);
795 }
796 
797 /// Check some of the conditions that must be met for the loop to be
798 /// convertible.
799 bool LoopConvertCheck::isConvertible(ASTContext *Context,
800  const ast_matchers::BoundNodes &Nodes,
801  const ForStmt *Loop,
802  LoopFixerKind FixerKind) {
803  // If we already modified the range of this for loop, don't do any further
804  // updates on this iteration.
805  if (TUInfo->getReplacedVars().count(Loop))
806  return false;
807 
808  // Check that we have exactly one index variable and at most one end variable.
809  const auto *InitVar = Nodes.getNodeAs<VarDecl>(InitVarName);
810 
811  // FIXME: Try to put most of this logic inside a matcher.
812  if (FixerKind == LFK_Iterator || FixerKind == LFK_ReverseIterator) {
813  QualType InitVarType = InitVar->getType();
814  QualType CanonicalInitVarType = InitVarType.getCanonicalType();
815 
816  const auto *BeginCall = Nodes.getNodeAs<CXXMemberCallExpr>(BeginCallName);
817  assert(BeginCall && "Bad Callback. No begin call expression");
818  QualType CanonicalBeginType =
819  BeginCall->getMethodDecl()->getReturnType().getCanonicalType();
820  if (CanonicalBeginType->isPointerType() &&
821  CanonicalInitVarType->isPointerType()) {
822  // If the initializer and the variable are both pointers check if the
823  // un-qualified pointee types match, otherwise we don't use auto.
824  if (!Context->hasSameUnqualifiedType(
825  CanonicalBeginType->getPointeeType(),
826  CanonicalInitVarType->getPointeeType()))
827  return false;
828  }
829  } else if (FixerKind == LFK_PseudoArray) {
830  // This call is required to obtain the container.
831  const auto *EndCall = Nodes.getNodeAs<CXXMemberCallExpr>(EndCallName);
832  if (!EndCall || !dyn_cast<MemberExpr>(EndCall->getCallee()))
833  return false;
834  }
835  return true;
836 }
837 
838 void LoopConvertCheck::check(const MatchFinder::MatchResult &Result) {
839  const BoundNodes &Nodes = Result.Nodes;
840  Confidence ConfidenceLevel(Confidence::CL_Safe);
841  ASTContext *Context = Result.Context;
842 
843  const ForStmt *Loop;
844  LoopFixerKind FixerKind;
845  RangeDescriptor Descriptor;
846 
847  if ((Loop = Nodes.getNodeAs<ForStmt>(LoopNameArray))) {
848  FixerKind = LFK_Array;
849  } else if ((Loop = Nodes.getNodeAs<ForStmt>(LoopNameIterator))) {
850  FixerKind = LFK_Iterator;
851  } else if ((Loop = Nodes.getNodeAs<ForStmt>(LoopNameReverseIterator))) {
852  FixerKind = LFK_ReverseIterator;
853  } else {
854  Loop = Nodes.getNodeAs<ForStmt>(LoopNamePseudoArray);
855  assert(Loop && "Bad Callback. No for statement");
856  FixerKind = LFK_PseudoArray;
857  }
858 
859  if (!isConvertible(Context, Nodes, Loop, FixerKind))
860  return;
861 
862  const auto *LoopVar = Nodes.getNodeAs<VarDecl>(InitVarName);
863  const auto *EndVar = Nodes.getNodeAs<VarDecl>(EndVarName);
864 
865  // If the loop calls end()/size() after each iteration, lower our confidence
866  // level.
867  if (FixerKind != LFK_Array && !EndVar)
868  ConfidenceLevel.lowerTo(Confidence::CL_Reasonable);
869 
870  // If the end comparison isn't a variable, we can try to work with the
871  // expression the loop variable is being tested against instead.
872  const auto *EndCall = Nodes.getNodeAs<CXXMemberCallExpr>(EndCallName);
873  const auto *BoundExpr = Nodes.getNodeAs<Expr>(ConditionBoundName);
874 
875  // Find container expression of iterators and pseudoarrays, and determine if
876  // this expression needs to be dereferenced to obtain the container.
877  // With array loops, the container is often discovered during the
878  // ForLoopIndexUseVisitor traversal.
879  const Expr *ContainerExpr = nullptr;
880  if (FixerKind == LFK_Iterator || FixerKind == LFK_ReverseIterator) {
881  ContainerExpr = findContainer(
882  Context, LoopVar->getInit(), EndVar ? EndVar->getInit() : EndCall,
883  &Descriptor.ContainerNeedsDereference,
884  /*IsReverse=*/FixerKind == LFK_ReverseIterator);
885  } else if (FixerKind == LFK_PseudoArray) {
886  ContainerExpr = EndCall->getImplicitObjectArgument();
887  Descriptor.ContainerNeedsDereference =
888  dyn_cast<MemberExpr>(EndCall->getCallee())->isArrow();
889  }
890 
891  // We must know the container or an array length bound.
892  if (!ContainerExpr && !BoundExpr)
893  return;
894 
895  ForLoopIndexUseVisitor Finder(Context, LoopVar, EndVar, ContainerExpr,
896  BoundExpr,
897  Descriptor.ContainerNeedsDereference);
898 
899  // Find expressions and variables on which the container depends.
900  if (ContainerExpr) {
901  ComponentFinderASTVisitor ComponentFinder;
902  ComponentFinder.findExprComponents(ContainerExpr->IgnoreParenImpCasts());
903  Finder.addComponents(ComponentFinder.getComponents());
904  }
905 
906  // Find usages of the loop index. If they are not used in a convertible way,
907  // stop here.
908  if (!Finder.findAndVerifyUsages(Loop->getBody()))
909  return;
910  ConfidenceLevel.lowerTo(Finder.getConfidenceLevel());
911 
912  // Obtain the container expression, if we don't have it yet.
913  if (FixerKind == LFK_Array) {
914  ContainerExpr = Finder.getContainerIndexed()->IgnoreParenImpCasts();
915 
916  // Very few loops are over expressions that generate arrays rather than
917  // array variables. Consider loops over arrays that aren't just represented
918  // by a variable to be risky conversions.
919  if (!getReferencedVariable(ContainerExpr) &&
920  !isDirectMemberExpr(ContainerExpr))
921  ConfidenceLevel.lowerTo(Confidence::CL_Risky);
922  }
923 
924  // Find out which qualifiers we have to use in the loop range.
925  TraversalKindScope RAII(*Context, TK_AsIs);
926  const UsageResult &Usages = Finder.getUsages();
927  determineRangeDescriptor(Context, Nodes, Loop, FixerKind, ContainerExpr,
928  Usages, Descriptor);
929 
930  // Ensure that we do not try to move an expression dependent on a local
931  // variable declared inside the loop outside of it.
932  // FIXME: Determine when the external dependency isn't an expression converted
933  // by another loop.
934  TUInfo->getParentFinder().gatherAncestors(*Context);
935  DependencyFinderASTVisitor DependencyFinder(
936  &TUInfo->getParentFinder().getStmtToParentStmtMap(),
937  &TUInfo->getParentFinder().getDeclToParentStmtMap(),
938  &TUInfo->getReplacedVars(), Loop);
939 
940  if (DependencyFinder.dependsOnInsideVariable(ContainerExpr) ||
941  Descriptor.ContainerString.empty() || Usages.empty() ||
942  ConfidenceLevel.getLevel() < MinConfidence)
943  return;
944 
945  doConversion(Context, LoopVar, getReferencedVariable(ContainerExpr), Usages,
946  Finder.getAliasDecl(), Finder.aliasUseRequired(),
947  Finder.aliasFromForInit(), Loop, Descriptor);
948 }
949 
950 llvm::StringRef LoopConvertCheck::getReverseFunction() const {
951  if (!ReverseFunction.empty())
952  return ReverseFunction;
953  if (UseReverseRanges)
954  return "std::ranges::reverse_view";
955  return "";
956 }
957 
958 llvm::StringRef LoopConvertCheck::getReverseHeader() const {
959  if (!ReverseHeader.empty())
960  return ReverseHeader;
961  if (UseReverseRanges && ReverseFunction.empty()) {
962  return "<ranges>";
963  }
964  return "";
965 }
966 
967 } // namespace modernize
968 } // namespace tidy
969 } // namespace clang
clang::tidy::modernize::makeArrayLoopMatcher
StatementMatcher makeArrayLoopMatcher()
The matcher for loops over arrays.
Definition: LoopConvertCheck.cpp:109
Range
CharSourceRange Range
SourceRange for the file name.
Definition: IncludeOrderCheck.cpp:38
clang::tidy::modernize::DependencyFinderASTVisitor
Class used to determine if an expression is dependent on a variable declared inside of the loop where...
Definition: LoopConvertUtils.h:114
clang::tidy::modernize::usagesReturnRValues
static bool usagesReturnRValues(const UsageResult &Usages)
Returns true if the elements of the container are never accessed by reference.
Definition: LoopConvertCheck.cpp:430
clang::tidy::modernize::getStringFromRange
static StringRef getStringFromRange(SourceManager &SourceMgr, const LangOptions &LangOpts, SourceRange Range)
Obtain the original source code text from a SourceRange.
Definition: LoopConvertCheck.cpp:362
llvm
Some operations such as code completion produce a set of candidates.
Definition: YAMLGenerator.cpp:28
clang::tidy::ClangTidyOptions::OptionMap
llvm::StringMap< ClangTidyValue > OptionMap
Definition: ClangTidyOptions.h:115
clang::tidy::modernize::Confidence::CL_Reasonable
@ CL_Reasonable
Definition: LoopConvertUtils.h:254
clang::tidy::modernize::DerefByValueResultName
static const char DerefByValueResultName[]
Definition: LoopConvertCheck.cpp:68
clang::tidy::modernize::UsageResult
llvm::SmallVector< Usage, 8 > UsageResult
Definition: LoopConvertUtils.h:275
E
const Expr * E
Definition: AvoidBindCheck.cpp:88
clang::tidy::modernize::LFK_ReverseIterator
@ LFK_ReverseIterator
Definition: LoopConvertUtils.h:32
Type
NodeType Type
Definition: HTMLGenerator.cpp:73
clang::tidy::modernize::isDirectMemberExpr
static bool isDirectMemberExpr(const Expr *E)
Returns true when the given expression is a member expression whose base is this (implicitly or not).
Definition: LoopConvertCheck.cpp:386
Usage
const char Usage[]
Definition: ClangReorderFields.cpp:50
clang::tidy::modernize::getDeclRef
const DeclRefExpr * getDeclRef(const Expr *E)
Returns the DeclRefExpr represented by E, or NULL if there isn't one.
Definition: LoopConvertUtils.cpp:204
clang::clangd::TypeHierarchyDirection::Parents
@ Parents
clang::tidy::OptionEnumMapping< modernize::Confidence::Level >::getEnumMapping
static llvm::ArrayRef< std::pair< modernize::Confidence::Level, StringRef > > getEnumMapping()
Definition: LoopConvertCheck.cpp:35
clang::tidy::modernize::InitVarName
static const char InitVarName[]
Definition: LoopConvertCheck.cpp:64
clang::tidy::modernize::DerefByRefResultName
static const char DerefByRefResultName[]
Definition: LoopConvertCheck.cpp:69
clang::tidy::modernize::integerComparisonMatcher
static const StatementMatcher integerComparisonMatcher()
Definition: LoopConvertCheck.cpp:71
clang::tidy::modernize::Usage::UK_CaptureByCopy
@ UK_CaptureByCopy
Definition: LoopConvertUtils.h:228
clang::tidy::cppcoreguidelines::getSourceText
static std::string getSourceText(const CXXDestructorDecl &Destructor)
Definition: VirtualClassDestructorCheck.cpp:109
clang::tidy::modernize::makePseudoArrayLoopMatcher
StatementMatcher makePseudoArrayLoopMatcher()
The matcher used for array-like containers (pseudoarrays).
Definition: LoopConvertCheck.cpp:241
clang::tidy::utils::IncludeInserter::registerPreprocessor
void registerPreprocessor(Preprocessor *PP)
Registers this with the Preprocessor PP, must be called before this class is used.
Definition: IncludeInserter.cpp:42
clang::tidy::OptionEnumMapping
This class should be specialized by any enum type that needs to be converted to and from an llvm::Str...
Definition: ClangTidyCheck.h:30
clang::tidy::modernize::usagesAreConst
static bool usagesAreConst(ASTContext *Context, const UsageResult &Usages)
Returns true when it can be guaranteed that the elements of the container are not being modified.
Definition: LoopConvertCheck.cpp:414
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidyCheck.h:54
clang::tidy::modernize::Confidence::lowerTo
void lowerTo(Confidence::Level Level)
Lower the internal confidence level to Level, but do not raise it.
Definition: LoopConvertUtils.h:263
clang::tidy::modernize::LoopConvertCheck::check
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Definition: LoopConvertCheck.cpp:838
clang::tidy::modernize::Usage
The information needed to describe a valid convertible usage of an array index or iterator.
Definition: LoopConvertUtils.h:210
clang::tidy::modernize::canBeModified
static bool canBeModified(ASTContext *Context, const Expr *E)
Given an expression that represents an usage of an element from the containter that we are iterating ...
Definition: LoopConvertCheck.cpp:395
clang::tidy::modernize::Confidence::CL_Safe
@ CL_Safe
Definition: LoopConvertUtils.h:257
clang::tidy::modernize::arrayConditionMatcher
static StatementMatcher arrayConditionMatcher(internal::Matcher< Expr > LimitExpr)
Definition: LoopConvertCheck.cpp:87
LoopConvertCheck.h
SourceMgr
llvm::SourceMgr * SourceMgr
Definition: ConfigCompile.cpp:102
clang::tidy::modernize::Confidence
A class to encapsulate lowering of the tool's confidence level.
Definition: LoopConvertUtils.h:247
clang::tidy::modernize::EndCallName
static const char EndCallName[]
Definition: LoopConvertCheck.cpp:66
clang::tidy::ClangTidyCheck::getLangOpts
const LangOptions & getLangOpts() const
Returns the language options from the context.
Definition: ClangTidyCheck.h:420
clang::tidy::modernize::ForLoopIndexUseVisitor
Discover usages of expressions consisting of index or iterator access.
Definition: LoopConvertUtils.h:288
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::modernize::EndVarName
static const char EndVarName[]
Definition: LoopConvertCheck.cpp:67
Offset
size_t Offset
Definition: CodeComplete.cpp:1173
clang::tidy::modernize::getReferencedVariable
static const ValueDecl * getReferencedVariable(const Expr *E)
If the given expression is actually a DeclRefExpr or a MemberExpr, find and return the underlying Val...
Definition: LoopConvertCheck.cpp:376
clang::tidy::modernize::findContainer
static const Expr * findContainer(ASTContext *Context, const Expr *BeginExpr, const Expr *EndExpr, bool *ContainerNeedsDereference, bool IsReverse)
Determines the container whose begin() and end() functions are called for an iterator-based loop.
Definition: LoopConvertCheck.cpp:336
clang::tidy::modernize::LoopConvertCheck::storeOptions
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
Definition: LoopConvertCheck.cpp:484
clang::tidy::modernize::containerIsConst
static bool containerIsConst(const Expr *ContainerExpr, bool Dereference)
Returns true if the container is const-qualified.
Definition: LoopConvertCheck.cpp:439
clang::tidy::modernize::ComponentFinderASTVisitor::getComponents
const ComponentVector & getComponents()
Accessor for Components.
Definition: LoopConvertUtils.h:101
clang::tidy::modernize::ConditionBoundName
static const char ConditionBoundName[]
Definition: LoopConvertCheck.cpp:63
clang::tidy::modernize::digThroughConstructorsConversions
const Expr * digThroughConstructorsConversions(const Expr *E)
Look through conversion/copy constructors and member functions to find the explicit initialization ex...
Definition: LoopConvertUtils.cpp:169
clang::tidy::modernize::getContainerFromBeginEndCall
static const Expr * getContainerFromBeginEndCall(const Expr *Init, bool IsBegin, bool *IsArrow, bool IsReverse)
Determine whether Init appears to be an initializing an iterator.
Definition: LoopConvertCheck.cpp:304
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidyCheck.h:416
clang::tidy::modernize::LoopFixerKind
LoopFixerKind
Definition: LoopConvertUtils.h:29
clang::tidy::modernize::DependencyFinderASTVisitor::dependsOnInsideVariable
bool dependsOnInsideVariable(const clang::Stmt *Body)
Run the analysis on Body, and return true iff the expression depends on some variable declared within...
Definition: LoopConvertUtils.h:154
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:71
clang::tidy::modernize::LoopNameIterator
static const char LoopNameIterator[]
Definition: LoopConvertCheck.cpp:60
Name
static constexpr llvm::StringLiteral Name
Definition: UppercaseLiteralSuffixCheck.cpp:28
clang::tidy::modernize::Usage::UK_MemberThroughArrow
@ UK_MemberThroughArrow
Definition: LoopConvertUtils.h:225
clang::tidy::modernize::TUTrackingInfo
Definition: LoopConvertUtils.h:405
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
Definition: ClangTidyCheck.cpp:25
clang::tidy::modernize::LFK_Array
@ LFK_Array
Definition: LoopConvertUtils.h:30
clang::tidy::modernize::ComponentFinderASTVisitor
Class used to find the variables and member expressions on which an arbitrary expression depends.
Definition: LoopConvertUtils.h:90
clang::tidy::modernize::VariableNamer
Create names for generated variables within a particular statement.
Definition: LoopConvertUtils.h:427
clang::tidy::modernize::LoopConvertCheck::registerPPCallbacks
void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) override
Override this to register PPCallbacks in the preprocessor.
Definition: LoopConvertCheck.cpp:494
Output
std::string Output
Definition: TraceTests.cpp:162
clang::tidy::modernize::LoopNamePseudoArray
static const char LoopNamePseudoArray[]
Definition: LoopConvertCheck.cpp:62
clang::tidy::bugprone::PP
static Preprocessor * PP
Definition: BadSignalToKillThreadCheck.cpp:29
clang::tidy::modernize::LoopNameReverseIterator
static const char LoopNameReverseIterator[]
Definition: LoopConvertCheck.cpp:61
clang::tidy::modernize::Confidence::CL_Risky
@ CL_Risky
Definition: LoopConvertUtils.h:251
clang::tidy::ClangTidyCheck::configurationDiag
DiagnosticBuilder configurationDiag(StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning) const
Adds a diagnostic to report errors in the check's configuration.
Definition: ClangTidyCheck.cpp:36
clang::tidy::modernize::makeIteratorLoopMatcher
StatementMatcher makeIteratorLoopMatcher(bool IsReverse)
The matcher used for iterator-based for loops.
Definition: LoopConvertCheck.cpp:144
clang::tidy::modernize::initToZeroMatcher
static const DeclarationMatcher initToZeroMatcher()
Definition: LoopConvertCheck.cpp:76
clang::tidy::utils::IncludeInserter::getStyle
IncludeSorter::IncludeStyle getStyle() const
Definition: IncludeInserter.h:84
clang::tidy::modernize::LoopNameArray
static const char LoopNameArray[]
Definition: LoopConvertCheck.cpp:59
clang::tidy::modernize::LFK_PseudoArray
@ LFK_PseudoArray
Definition: LoopConvertUtils.h:33
clang::tidy::modernize::LoopConvertCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: LoopConvertCheck.cpp:500
clang::tidy::modernize::ComponentFinderASTVisitor::findExprComponents
void findExprComponents(const clang::Expr *SourceExpr)
Find the components of an expression and place them in a ComponentVector.
Definition: LoopConvertUtils.h:96
clang::tidy::modernize::incrementVarMatcher
static const StatementMatcher incrementVarMatcher()
Definition: LoopConvertCheck.cpp:82
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::tidy::modernize::LFK_Iterator
@ LFK_Iterator
Definition: LoopConvertUtils.h:31
clang::tidy::modernize::areSameExpr
bool areSameExpr(ASTContext *Context, const Expr *First, const Expr *Second)
Returns true when two Exprs are equivalent.
Definition: LoopConvertUtils.cpp:193
clang::tidy::utils::IncludeInserter::createIncludeInsertion
llvm::Optional< FixItHint > createIncludeInsertion(FileID FileID, llvm::StringRef Header)
Creates a Header inclusion directive fixit in the File FileID.
Definition: IncludeInserter.cpp:70
SM
const SourceManager & SM
Definition: IncludeCleaner.cpp:140
clang::tidy::ClangTidyCheck::OptionsView::store
void store(ClangTidyOptions::OptionMap &Options, StringRef LocalName, StringRef Value) const
Stores an option with the check-local name LocalName with string value Value to Options.
Definition: ClangTidyCheck.cpp:120
clang::tidy::modernize::BeginCallName
static const char BeginCallName[]
Definition: LoopConvertCheck.cpp:65
clang::tidy::modernize::Confidence::getLevel
Level getLevel() const
Return the internal confidence level.
Definition: LoopConvertUtils.h:268
clang::tidy::OptionEnumMapping< modernize::VariableNamer::NamingStyle >::getEnumMapping
static llvm::ArrayRef< std::pair< modernize::VariableNamer::NamingStyle, StringRef > > getEnumMapping()
Definition: LoopConvertCheck.cpp:47