clang-tools 10.0.0

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/SmallVector.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/StringSwitch.h"
20 #include "llvm/Support/Casting.h"
21 #include <cassert>
22 #include <cstring>
23 #include <utility>
24
25 using namespace clang::ast_matchers;
26 using namespace llvm;
27
28 namespace clang {
29 namespace tidy {
30 namespace modernize {
31
32 static const char LoopNameArray[] = "forLoopArray";
33 static const char LoopNameIterator[] = "forLoopIterator";
34 static const char LoopNamePseudoArray[] = "forLoopPseudoArray";
35 static const char ConditionBoundName[] = "conditionBound";
36 static const char ConditionVarName[] = "conditionVar";
37 static const char IncrementVarName[] = "incrementVar";
38 static const char InitVarName[] = "initVar";
39 static const char BeginCallName[] = "beginCall";
40 static const char EndCallName[] = "endCall";
41 static const char ConditionEndVarName[] = "conditionEndVar";
42 static const char EndVarName[] = "endVar";
43 static const char DerefByValueResultName[] = "derefByValueResult";
44 static const char DerefByRefResultName[] = "derefByRefResult";
45
46 // shared matchers
47 static const TypeMatcher AnyType() { return anything(); }
48
49 static const StatementMatcher IntegerComparisonMatcher() {
50 return expr(ignoringParenImpCasts(
51 declRefExpr(to(varDecl(hasType(isInteger())).bind(ConditionVarName)))));
52 }
53
54 static const DeclarationMatcher InitToZeroMatcher() {
55 return varDecl(
56 hasInitializer(ignoringParenImpCasts(integerLiteral(equals(0)))))
57 .bind(InitVarName);
58 }
59
60 static const StatementMatcher IncrementVarMatcher() {
61 return declRefExpr(to(varDecl(hasType(isInteger())).bind(IncrementVarName)));
62 }
63
64 /// The matcher for loops over arrays.
65 ///
66 /// In this general example, assuming 'j' and 'k' are of integral type:
67 /// \code
68 /// for (int i = 0; j < 3 + 2; ++k) { ... }
69 /// \endcode
70 /// The following string identifiers are bound to these parts of the AST:
71 /// ConditionVarName: 'j' (as a VarDecl)
72 /// ConditionBoundName: '3 + 2' (as an Expr)
73 /// InitVarName: 'i' (as a VarDecl)
74 /// IncrementVarName: 'k' (as a VarDecl)
75 /// LoopName: The entire for loop (as a ForStmt)
76 ///
77 /// Client code will need to make sure that:
78 /// - The three index variables identified by the matcher are the same
79 /// VarDecl.
80 /// - The index variable is only used as an array index.
81 /// - All arrays indexed by the loop are the same.
82 StatementMatcher makeArrayLoopMatcher() {
83 StatementMatcher ArrayBoundMatcher =
84 expr(hasType(isInteger())).bind(ConditionBoundName);
85
86 return forStmt(
87 unless(isInTemplateInstantiation()),
88 hasLoopInit(declStmt(hasSingleDecl(InitToZeroMatcher()))),
89 hasCondition(anyOf(
90 binaryOperator(hasOperatorName("<"),
91 hasLHS(IntegerComparisonMatcher()),
92 hasRHS(ArrayBoundMatcher)),
93 binaryOperator(hasOperatorName(">"), hasLHS(ArrayBoundMatcher),
94 hasRHS(IntegerComparisonMatcher())))),
95 hasIncrement(unaryOperator(hasOperatorName("++"),
96 hasUnaryOperand(IncrementVarMatcher()))))
97 .bind(LoopNameArray);
98 }
99
100 /// The matcher used for iterator-based for loops.
101 ///
102 /// This matcher is more flexible than array-based loops. It will match
103 /// catch loops of the following textual forms (regardless of whether the
104 /// iterator type is actually a pointer type or a class type):
105 ///
106 /// Assuming f, g, and h are of type containerType::iterator,
107 /// \code
108 /// for (containerType::iterator it = container.begin(),
109 /// e = createIterator(); f != g; ++h) { ... }
110 /// for (containerType::iterator it = container.begin();
111 /// f != anotherContainer.end(); ++h) { ... }
112 /// \endcode
113 /// The following string identifiers are bound to the parts of the AST:
114 /// InitVarName: 'it' (as a VarDecl)
115 /// ConditionVarName: 'f' (as a VarDecl)
116 /// LoopName: The entire for loop (as a ForStmt)
117 /// In the first example only:
118 /// EndVarName: 'e' (as a VarDecl)
119 /// ConditionEndVarName: 'g' (as a VarDecl)
120 /// In the second example only:
121 /// EndCallName: 'container.end()' (as a CXXMemberCallExpr)
122 ///
123 /// Client code will need to make sure that:
124 /// - The iterator variables 'it', 'f', and 'h' are the same.
125 /// - The two containers on which 'begin' and 'end' are called are the same.
126 /// - If the end iterator variable 'g' is defined, it is the same as 'f'.
127 StatementMatcher makeIteratorLoopMatcher() {
128 StatementMatcher BeginCallMatcher =
129 cxxMemberCallExpr(
130 argumentCountIs(0),
131 callee(cxxMethodDecl(anyOf(hasName("begin"), hasName("cbegin")))))
132 .bind(BeginCallName);
133
134 DeclarationMatcher InitDeclMatcher =
135 varDecl(hasInitializer(anyOf(ignoringParenImpCasts(BeginCallMatcher),
136 materializeTemporaryExpr(
137 ignoringParenImpCasts(BeginCallMatcher)),
138 hasDescendant(BeginCallMatcher))))
139 .bind(InitVarName);
140
141 DeclarationMatcher EndDeclMatcher =
142 varDecl(hasInitializer(anything())).bind(EndVarName);
143
144 StatementMatcher EndCallMatcher = cxxMemberCallExpr(
145 argumentCountIs(0),
146 callee(cxxMethodDecl(anyOf(hasName("end"), hasName("cend")))));
147
148 StatementMatcher IteratorBoundMatcher =
149 expr(anyOf(ignoringParenImpCasts(
150 declRefExpr(to(varDecl().bind(ConditionEndVarName)))),
151 ignoringParenImpCasts(expr(EndCallMatcher).bind(EndCallName)),
152 materializeTemporaryExpr(ignoringParenImpCasts(
153 expr(EndCallMatcher).bind(EndCallName)))));
154
155 StatementMatcher IteratorComparisonMatcher = expr(
156 ignoringParenImpCasts(declRefExpr(to(varDecl().bind(ConditionVarName)))));
157
158 auto OverloadedNEQMatcher = ignoringImplicit(
159 cxxOperatorCallExpr(hasOverloadedOperatorName("!="), argumentCountIs(2),
160 hasArgument(0, IteratorComparisonMatcher),
161 hasArgument(1, IteratorBoundMatcher)));
162
163 // This matcher tests that a declaration is a CXXRecordDecl that has an
164 // overloaded operator*(). If the operator*() returns by value instead of by
165 // reference then the return type is tagged with DerefByValueResultName.
166 internal::Matcher<VarDecl> TestDerefReturnsByValue =
167 hasType(hasUnqualifiedDesugaredType(
168 recordType(hasDeclaration(cxxRecordDecl(hasMethod(cxxMethodDecl(
169 hasOverloadedOperatorName("*"),
170 anyOf(
171 // Tag the return type if it's by value.
172 returns(qualType(unless(hasCanonicalType(referenceType())))
173 .bind(DerefByValueResultName)),
174 returns(
175 // Skip loops where the iterator's operator* returns an
176 // rvalue reference. This is just weird.
177 qualType(unless(hasCanonicalType(rValueReferenceType())))
178 .bind(DerefByRefResultName))))))))));
179
180 return forStmt(
181 unless(isInTemplateInstantiation()),
182 hasLoopInit(anyOf(declStmt(declCountIs(2),
183 containsDeclaration(0, InitDeclMatcher),
184 containsDeclaration(1, EndDeclMatcher)),
185 declStmt(hasSingleDecl(InitDeclMatcher)))),
186 hasCondition(
187 anyOf(binaryOperator(hasOperatorName("!="),
188 hasLHS(IteratorComparisonMatcher),
189 hasRHS(IteratorBoundMatcher)),
190 binaryOperator(hasOperatorName("!="),
191 hasLHS(IteratorBoundMatcher),
192 hasRHS(IteratorComparisonMatcher)),
193 OverloadedNEQMatcher)),
194 hasIncrement(anyOf(
195 unaryOperator(hasOperatorName("++"),
196 hasUnaryOperand(declRefExpr(
197 to(varDecl(hasType(pointsTo(AnyType())))
198 .bind(IncrementVarName))))),
199 cxxOperatorCallExpr(
200 hasOverloadedOperatorName("++"),
201 hasArgument(
202 0, declRefExpr(to(varDecl(TestDerefReturnsByValue)
203 .bind(IncrementVarName))))))))
204 .bind(LoopNameIterator);
205 }
206
207 /// The matcher used for array-like containers (pseudoarrays).
208 ///
209 /// This matcher is more flexible than array-based loops. It will match
210 /// loops of the following textual forms (regardless of whether the
211 /// iterator type is actually a pointer type or a class type):
212 ///
213 /// Assuming f, g, and h are of type containerType::iterator,
214 /// \code
215 /// for (int i = 0, j = container.size(); f < g; ++h) { ... }
216 /// for (int i = 0; f < container.size(); ++h) { ... }
217 /// \endcode
218 /// The following string identifiers are bound to the parts of the AST:
219 /// InitVarName: 'i' (as a VarDecl)
220 /// ConditionVarName: 'f' (as a VarDecl)
221 /// LoopName: The entire for loop (as a ForStmt)
222 /// In the first example only:
223 /// EndVarName: 'j' (as a VarDecl)
224 /// ConditionEndVarName: 'g' (as a VarDecl)
225 /// In the second example only:
226 /// EndCallName: 'container.size()' (as a CXXMemberCallExpr)
227 ///
228 /// Client code will need to make sure that:
229 /// - The index variables 'i', 'f', and 'h' are the same.
230 /// - The containers on which 'size()' is called is the container indexed.
231 /// - The index variable is only used in overloaded operator[] or
232 /// container.at().
233 /// - If the end iterator variable 'g' is defined, it is the same as 'j'.
234 /// - The container's iterators would not be invalidated during the loop.
235 StatementMatcher makePseudoArrayLoopMatcher() {
236 // Test that the incoming type has a record declaration that has methods
237 // called 'begin' and 'end'. If the incoming type is const, then make sure
238 // these methods are also marked const.
239 //
240 // FIXME: To be completely thorough this matcher should also ensure the
241 // return type of begin/end is an iterator that dereferences to the same as
242 // what operator[] or at() returns. Such a test isn't likely to fail except
243 // for pathological cases.
244 //
245 // FIXME: Also, a record doesn't necessarily need begin() and end(). Free
246 // functions called begin() and end() taking the container as an argument
247 // are also allowed.
248 TypeMatcher RecordWithBeginEnd = qualType(anyOf(
249 qualType(
250 isConstQualified(),
251 hasUnqualifiedDesugaredType(recordType(hasDeclaration(cxxRecordDecl(
252 hasMethod(cxxMethodDecl(hasName("begin"), isConst())),
253 hasMethod(cxxMethodDecl(hasName("end"),
254 isConst())))) // hasDeclaration
255 ))), // qualType
256 qualType(unless(isConstQualified()),
257 hasUnqualifiedDesugaredType(recordType(hasDeclaration(
258 cxxRecordDecl(hasMethod(hasName("begin")),
259 hasMethod(hasName("end"))))))) // qualType
260 ));
261
262 StatementMatcher SizeCallMatcher = cxxMemberCallExpr(
263 argumentCountIs(0),
264 callee(cxxMethodDecl(anyOf(hasName("size"), hasName("length")))),
265 on(anyOf(hasType(pointsTo(RecordWithBeginEnd)),
266 hasType(RecordWithBeginEnd))));
267
268 StatementMatcher EndInitMatcher =
269 expr(anyOf(ignoringParenImpCasts(expr(SizeCallMatcher).bind(EndCallName)),
270 explicitCastExpr(hasSourceExpression(ignoringParenImpCasts(
271 expr(SizeCallMatcher).bind(EndCallName))))));
272
273 DeclarationMatcher EndDeclMatcher =
274 varDecl(hasInitializer(EndInitMatcher)).bind(EndVarName);
275
276 StatementMatcher IndexBoundMatcher =
277 expr(anyOf(ignoringParenImpCasts(declRefExpr(to(
278 varDecl(hasType(isInteger())).bind(ConditionEndVarName)))),
279 EndInitMatcher));
280
281 return forStmt(
282 unless(isInTemplateInstantiation()),
283 hasLoopInit(
284 anyOf(declStmt(declCountIs(2),
285 containsDeclaration(0, InitToZeroMatcher()),
286 containsDeclaration(1, EndDeclMatcher)),
287 declStmt(hasSingleDecl(InitToZeroMatcher())))),
288 hasCondition(anyOf(
289 binaryOperator(hasOperatorName("<"),
290 hasLHS(IntegerComparisonMatcher()),
291 hasRHS(IndexBoundMatcher)),
292 binaryOperator(hasOperatorName(">"), hasLHS(IndexBoundMatcher),
293 hasRHS(IntegerComparisonMatcher())))),
294 hasIncrement(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) {
306 // FIXME: Maybe allow declaration/initialization outside of the for loop.
307 const auto *TheCall =
308 dyn_cast_or_null<CXXMemberCallExpr>(digThroughConstructors(Init));
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 StringRef TargetName = IsBegin ? "begin" : "end";
317 StringRef ConstTargetName = IsBegin ? "cbegin" : "cend";
318 if (Name != TargetName && Name != ConstTargetName)
319 return nullptr;
320
321 const Expr *SourceExpr = Member->getBase();
322 if (!SourceExpr)
323 return nullptr;
324
325 *IsArrow = Member->isArrow();
326 return SourceExpr;
327 }
328
329 /// Determines the container whose begin() and end() functions are called
330 /// for an iterator-based loop.
331 ///
332 /// BeginExpr must be a member call to a function named "begin()", and EndExpr
333 /// must be a member.
334 static const Expr *findContainer(ASTContext *Context, const Expr *BeginExpr,
335 const Expr *EndExpr,
336 bool *ContainerNeedsDereference) {
337 // Now that we know the loop variable and test expression, make sure they are
338 // valid.
339 bool BeginIsArrow = false;
340 bool EndIsArrow = false;
341 const Expr *BeginContainerExpr =
342 getContainerFromBeginEndCall(BeginExpr, /*IsBegin=*/true, &BeginIsArrow);
343 if (!BeginContainerExpr)
344 return nullptr;
345
346 const Expr *EndContainerExpr =
347 getContainerFromBeginEndCall(EndExpr, /*IsBegin=*/false, &EndIsArrow);
348 // Disallow loops that try evil things like this (note the dot and arrow):
349 // for (IteratorType It = Obj.begin(), E = Obj->end(); It != E; ++It) { }
350 if (!EndContainerExpr || BeginIsArrow != EndIsArrow ||
351 !areSameExpr(Context, EndContainerExpr, BeginContainerExpr))
352 return nullptr;
353
354 *ContainerNeedsDereference = BeginIsArrow;
355 return BeginContainerExpr;
356 }
357
358 /// Obtain the original source code text from a SourceRange.
359 static StringRef getStringFromRange(SourceManager &SourceMgr,
360 const LangOptions &LangOpts,
361 SourceRange Range) {
362 if (SourceMgr.getFileID(Range.getBegin()) !=
363 SourceMgr.getFileID(Range.getEnd())) {
364 return StringRef(); // Empty string.
365 }
366
367 return Lexer::getSourceText(CharSourceRange(Range, true), SourceMgr,
368 LangOpts);
369 }
370
371 /// If the given expression is actually a DeclRefExpr or a MemberExpr,
372 /// find and return the underlying ValueDecl; otherwise, return NULL.
373 static const ValueDecl *getReferencedVariable(const Expr *E) {
374 if (const DeclRefExpr *DRE = getDeclRef(E))
375 return dyn_cast<VarDecl>(DRE->getDecl());
376 if (const auto *Mem = dyn_cast<MemberExpr>(E->IgnoreParenImpCasts()))
377 return dyn_cast<FieldDecl>(Mem->getMemberDecl());
378 return nullptr;
379 }
380
381 /// Returns true when the given expression is a member expression
382 /// whose base is `this` (implicitly or not).
383 static bool isDirectMemberExpr(const Expr *E) {
384 if (const auto *Member = dyn_cast<MemberExpr>(E->IgnoreParenImpCasts()))
385 return isa<CXXThisExpr>(Member->getBase()->IgnoreParenImpCasts());
386 return false;
387 }
388
389 /// Given an expression that represents an usage of an element from the
390 /// containter that we are iterating over, returns false when it can be
391 /// guaranteed this element cannot be modified as a result of this usage.
392 static bool canBeModified(ASTContext *Context, const Expr *E) {
393 if (E->getType().isConstQualified())
394 return false;
395 auto Parents = Context->getParents(*E);
396 if (Parents.size() != 1)
397 return true;
398 if (const auto *Cast = Parents[0].get<ImplicitCastExpr>()) {
399 if ((Cast->getCastKind() == CK_NoOp &&
400 Cast->getType() == E->getType().withConst()) ||
401 (Cast->getCastKind() == CK_LValueToRValue &&
402 !Cast->getType().isNull() && Cast->getType()->isFundamentalType()))
403 return false;
404 }
405 // FIXME: Make this function more generic.
406 return true;
407 }
408
409 /// Returns true when it can be guaranteed that the elements of the
410 /// container are not being modified.
411 static bool usagesAreConst(ASTContext *Context, const UsageResult &Usages) {
412 for (const Usage &U : Usages) {
413 // Lambda captures are just redeclarations (VarDecl) of the same variable,
414 // not expressions. If we want to know if a variable that is captured by
415 // reference can be modified in an usage inside the lambda's body, we need
416 // to find the expression corresponding to that particular usage, later in
417 // this loop.
418 if (U.Kind != Usage::UK_CaptureByCopy && U.Kind != Usage::UK_CaptureByRef &&
419 canBeModified(Context, U.Expression))
420 return false;
421 }
422 return true;
423 }
424
425 /// Returns true if the elements of the container are never accessed
426 /// by reference.
427 static bool usagesReturnRValues(const UsageResult &Usages) {
428 for (const auto &U : Usages) {
429 if (U.Expression && !U.Expression->isRValue())
430 return false;
431 }
432 return true;
433 }
434
435 /// Returns true if the container is const-qualified.
436 static bool containerIsConst(const Expr *ContainerExpr, bool Dereference) {
437 if (const auto *VDec = getReferencedVariable(ContainerExpr)) {
438 QualType CType = VDec->getType();
439 if (Dereference) {
440 if (!CType->isPointerType())
441 return false;
442 CType = CType->getPointeeType();
443 }
444 // If VDec is a reference to a container, Dereference is false,
445 // but we still need to check the const-ness of the underlying container
446 // type.
447 CType = CType.getNonReferenceType();
448 return CType.isConstQualified();
449 }
450 return false;
451 }
452
453 LoopConvertCheck::RangeDescriptor::RangeDescriptor()
454 : ContainerNeedsDereference(false), DerefByConstRef(false),
455 DerefByValue(false) {}
456
457 LoopConvertCheck::LoopConvertCheck(StringRef Name, ClangTidyContext *Context)
458 : ClangTidyCheck(Name, Context), TUInfo(new TUTrackingInfo),
459 MaxCopySize(std::stoull(Options.get("MaxCopySize", "16"))),
460 MinConfidence(StringSwitch<Confidence::Level>(
461 Options.get("MinConfidence", "reasonable"))
462 .Case("safe", Confidence::CL_Safe)
463 .Case("risky", Confidence::CL_Risky)
464 .Default(Confidence::CL_Reasonable)),
465 NamingStyle(StringSwitch<VariableNamer::NamingStyle>(
466 Options.get("NamingStyle", "CamelCase"))
467 .Case("camelBack", VariableNamer::NS_CamelBack)
468 .Case("lower_case", VariableNamer::NS_LowerCase)
469 .Case("UPPER_CASE", VariableNamer::NS_UpperCase)
470 .Default(VariableNamer::NS_CamelCase)) {}
471
472 void LoopConvertCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
473 Options.store(Opts, "MaxCopySize", std::to_string(MaxCopySize));
474 SmallVector<std::string, 3> Confs{"risky", "reasonable", "safe"};
475 Options.store(Opts, "MinConfidence", Confs[static_cast<int>(MinConfidence)]);
476
477 SmallVector<std::string, 4> Styles{"camelBack", "CamelCase", "lower_case",
478 "UPPER_CASE"};
479 Options.store(Opts, "NamingStyle", Styles[static_cast<int>(NamingStyle)]);
480 }
481
482 void LoopConvertCheck::registerMatchers(MatchFinder *Finder) {
483 // Only register the matchers for C++. Because this checker is used for
484 // modernization, it is reasonable to run it on any C++ standard with the
485 // assumption the user is trying to modernize their codebase.
486 if (!getLangOpts().CPlusPlus)
487 return;
488
489 Finder->addMatcher(makeArrayLoopMatcher(), this);
490 Finder->addMatcher(makeIteratorLoopMatcher(), this);
491 Finder->addMatcher(makePseudoArrayLoopMatcher(), this);
492 }
493
494 /// Given the range of a single declaration, such as:
495 /// \code
496 /// unsigned &ThisIsADeclarationThatCanSpanSeveralLinesOfCode =
497 /// InitializationValues[I];
498 /// next_instruction;
499 /// \endcode
500 /// Finds the range that has to be erased to remove this declaration without
501 /// leaving empty lines, by extending the range until the beginning of the
502 /// next instruction.
503 ///
504 /// We need to delete a potential newline after the deleted alias, as
505 /// clang-format will leave empty lines untouched. For all other formatting we
506 /// rely on clang-format to fix it.
507 void LoopConvertCheck::getAliasRange(SourceManager &SM, SourceRange &Range) {
508 bool Invalid = false;
509 const char *TextAfter =
510 SM.getCharacterData(Range.getEnd().getLocWithOffset(1), &Invalid);
511 if (Invalid)
512 return;
513 unsigned Offset = std::strspn(TextAfter, " \t\r\n");
514 Range =
515 SourceRange(Range.getBegin(), Range.getEnd().getLocWithOffset(Offset));
516 }
517
518 /// Computes the changes needed to convert a given for loop, and
519 /// applies them.
520 void LoopConvertCheck::doConversion(
521 ASTContext *Context, const VarDecl *IndexVar,
522 const ValueDecl *MaybeContainer, const UsageResult &Usages,
523 const DeclStmt *AliasDecl, bool AliasUseRequired, bool AliasFromForInit,
524 const ForStmt *Loop, RangeDescriptor Descriptor) {
525 auto Diag = diag(Loop->getForLoc(), "use range-based for loop instead");
526
527 std::string VarName;
528 bool VarNameFromAlias = (Usages.size() == 1) && AliasDecl;
529 bool AliasVarIsRef = false;
530 bool CanCopy = true;
531
532 if (VarNameFromAlias) {
533 const auto *AliasVar = cast<VarDecl>(AliasDecl->getSingleDecl());
534 VarName = AliasVar->getName().str();
535
536 // Use the type of the alias if it's not the same
537 QualType AliasVarType = AliasVar->getType();
538 assert(!AliasVarType.isNull() && "Type in VarDecl is null");
539 if (AliasVarType->isReferenceType()) {
540 AliasVarType = AliasVarType.getNonReferenceType();
541 AliasVarIsRef = true;
542 }
543 if (Descriptor.ElemType.isNull() ||
544 !Context->hasSameUnqualifiedType(AliasVarType, Descriptor.ElemType))
545 Descriptor.ElemType = AliasVarType;
546
547 // We keep along the entire DeclStmt to keep the correct range here.
548 SourceRange ReplaceRange = AliasDecl->getSourceRange();
549
550 std::string ReplacementText;
551 if (AliasUseRequired) {
552 ReplacementText = VarName;
553 } else if (AliasFromForInit) {
554 // FIXME: Clang includes the location of the ';' but only for DeclStmt's
555 // in a for loop's init clause. Need to put this ';' back while removing
556 // the declaration of the alias variable. This is probably a bug.
557 ReplacementText = ";";
558 } else {
559 // Avoid leaving empty lines or trailing whitespaces.
560 getAliasRange(Context->getSourceManager(), ReplaceRange);
561 }
562
563 Diag << FixItHint::CreateReplacement(
564 CharSourceRange::getTokenRange(ReplaceRange), ReplacementText);
565 // No further replacements are made to the loop, since the iterator or index
566 // was used exactly once - in the initialization of AliasVar.
567 } else {
568 VariableNamer Namer(&TUInfo->getGeneratedDecls(),
569 &TUInfo->getParentFinder().getStmtToParentStmtMap(),
570 Loop, IndexVar, MaybeContainer, Context, NamingStyle);
571 VarName = Namer.createIndexName();
572 // First, replace all usages of the array subscript expression with our new
573 // variable.
574 for (const auto &Usage : Usages) {
575 std::string ReplaceText;
576 SourceRange Range = Usage.Range;
577 if (Usage.Expression) {
578 // If this is an access to a member through the arrow operator, after
579 // the replacement it must be accessed through the '.' operator.
580 ReplaceText = Usage.Kind == Usage::UK_MemberThroughArrow ? VarName + "."
581 : VarName;
582 auto Parents = Context->getParents(*Usage.Expression);
583 if (Parents.size() == 1) {
584 if (const auto *Paren = Parents[0].get<ParenExpr>()) {
585 // Usage.Expression will be replaced with the new index variable,
586 // and parenthesis around a simple DeclRefExpr can always be
587 // removed.
588 Range = Paren->getSourceRange();
589 } else if (const auto *UOP = Parents[0].get<UnaryOperator>()) {
590 // If we are taking the address of the loop variable, then we must
591 // not use a copy, as it would mean taking the address of the loop's
592 // local index instead.
593 // FIXME: This won't catch cases where the address is taken outside
594 // of the loop's body (for instance, in a function that got the
595 // loop's index as a const reference parameter), or where we take
596 // the address of a member (like "&Arr[i].A.B.C").
597 if (UOP->getOpcode() == UO_AddrOf)
598 CanCopy = false;
599 }
600 }
601 } else {
602 // The Usage expression is only null in case of lambda captures (which
603 // are VarDecl). If the index is captured by value, add '&' to capture
604 // by reference instead.
605 ReplaceText =
606 Usage.Kind == Usage::UK_CaptureByCopy ? "&" + VarName : VarName;
607 }
608 TUInfo->getReplacedVars().insert(std::make_pair(Loop, IndexVar));
609 Diag << FixItHint::CreateReplacement(
610 CharSourceRange::getTokenRange(Range), ReplaceText);
611 }
612 }
613
614 // Now, we need to construct the new range expression.
615 SourceRange ParenRange(Loop->getLParenLoc(), Loop->getRParenLoc());
616
617 QualType Type = Context->getAutoDeductType();
618 if (!Descriptor.ElemType.isNull() && Descriptor.ElemType->isFundamentalType())
619 Type = Descriptor.ElemType.getUnqualifiedType();
620
621 // If the new variable name is from the aliased variable, then the reference
622 // type for the new variable should only be used if the aliased variable was
623 // declared as a reference.
624 bool IsCheapToCopy =
625 !Descriptor.ElemType.isNull() &&
626 Descriptor.ElemType.isTriviallyCopyableType(*Context) &&
627 // TypeInfo::Width is in bits.
628 Context->getTypeInfo(Descriptor.ElemType).Width <= 8 * MaxCopySize;
629 bool UseCopy = CanCopy && ((VarNameFromAlias && !AliasVarIsRef) ||
630 (Descriptor.DerefByConstRef && IsCheapToCopy));
631
632 if (!UseCopy) {
633 if (Descriptor.DerefByConstRef) {
634 Type = Context->getLValueReferenceType(Context->getConstType(Type));
635 } else if (Descriptor.DerefByValue) {
636 if (!IsCheapToCopy)
637 Type = Context->getRValueReferenceType(Type);
638 } else {
639 Type = Context->getLValueReferenceType(Type);
640 }
641 }
642
643 StringRef MaybeDereference = Descriptor.ContainerNeedsDereference ? "*" : "";
644 std::string TypeString = Type.getAsString(getLangOpts());
645 std::string Range = ("(" + TypeString + " " + VarName + " : " +
646 MaybeDereference + Descriptor.ContainerString + ")")
647 .str();
648 Diag << FixItHint::CreateReplacement(
649 CharSourceRange::getTokenRange(ParenRange), Range);
650 TUInfo->getGeneratedDecls().insert(make_pair(Loop, VarName));
651 }
652
653 /// Returns a string which refers to the container iterated over.
654 StringRef LoopConvertCheck::getContainerString(ASTContext *Context,
655 const ForStmt *Loop,
656 const Expr *ContainerExpr) {
657 StringRef ContainerString;
658 if (isa<CXXThisExpr>(ContainerExpr->IgnoreParenImpCasts())) {
659 ContainerString = "this";
660 } else {
661 ContainerString =
662 getStringFromRange(Context->getSourceManager(), Context->getLangOpts(),
663 ContainerExpr->getSourceRange());
664 }
665
666 return ContainerString;
667 }
668
669 /// Determines what kind of 'auto' must be used after converting a for
670 /// loop that iterates over an array or pseudoarray.
671 void LoopConvertCheck::getArrayLoopQualifiers(ASTContext *Context,
672 const BoundNodes &Nodes,
673 const Expr *ContainerExpr,
674 const UsageResult &Usages,
675 RangeDescriptor &Descriptor) {
676 // On arrays and pseudoarrays, we must figure out the qualifiers from the
677 // usages.
678 if (usagesAreConst(Context, Usages) ||
679 containerIsConst(ContainerExpr, Descriptor.ContainerNeedsDereference)) {
680 Descriptor.DerefByConstRef = true;
681 }
682 if (usagesReturnRValues(Usages)) {
683 // If the index usages (dereference, subscript, at, ...) return rvalues,
684 // then we should not use a reference, because we need to keep the code
685 // correct if it mutates the returned objects.
686 Descriptor.DerefByValue = true;
687 }
688 // Try to find the type of the elements on the container, to check if
689 // they are trivially copyable.
690 for (const Usage &U : Usages) {
691 if (!U.Expression || U.Expression->getType().isNull())
692 continue;
693 QualType Type = U.Expression->getType().getCanonicalType();
694 if (U.Kind == Usage::UK_MemberThroughArrow) {
695 if (!Type->isPointerType()) {
696 continue;
697 }
698 Type = Type->getPointeeType();
699 }
700 Descriptor.ElemType = Type;
701 }
702 }
703
704 /// Determines what kind of 'auto' must be used after converting an
705 /// iterator based for loop.
706 void LoopConvertCheck::getIteratorLoopQualifiers(ASTContext *Context,
707 const BoundNodes &Nodes,
708 RangeDescriptor &Descriptor) {
709 // The matchers for iterator loops provide bound nodes to obtain this
710 // information.
711 const auto *InitVar = Nodes.getNodeAs<VarDecl>(InitVarName);
712 QualType CanonicalInitVarType = InitVar->getType().getCanonicalType();
713 const auto *DerefByValueType =
714 Nodes.getNodeAs<QualType>(DerefByValueResultName);
715 Descriptor.DerefByValue = DerefByValueType;
716
717 if (Descriptor.DerefByValue) {
718 // If the dereference operator returns by value then test for the
719 // canonical const qualification of the init variable type.
720 Descriptor.DerefByConstRef = CanonicalInitVarType.isConstQualified();
721 Descriptor.ElemType = *DerefByValueType;
722 } else {
723 if (const auto *DerefType =
724 Nodes.getNodeAs<QualType>(DerefByRefResultName)) {
725 // A node will only be bound with DerefByRefResultName if we're dealing
726 // with a user-defined iterator type. Test the const qualification of
727 // the reference type.
728 auto ValueType = DerefType->getNonReferenceType();
729
730 Descriptor.DerefByConstRef = ValueType.isConstQualified();
731 Descriptor.ElemType = ValueType;
732 } else {
733 // By nature of the matcher this case is triggered only for built-in
734 // iterator types (i.e. pointers).
735 assert(isa<PointerType>(CanonicalInitVarType) &&
736 "Non-class iterator type is not a pointer type");
737
738 // We test for const qualification of the pointed-at type.
739 Descriptor.DerefByConstRef =
740 CanonicalInitVarType->getPointeeType().isConstQualified();
741 Descriptor.ElemType = CanonicalInitVarType->getPointeeType();
742 }
743 }
744 }
745
746 /// Determines the parameters needed to build the range replacement.
747 void LoopConvertCheck::determineRangeDescriptor(
748 ASTContext *Context, const BoundNodes &Nodes, const ForStmt *Loop,
749 LoopFixerKind FixerKind, const Expr *ContainerExpr,
750 const UsageResult &Usages, RangeDescriptor &Descriptor) {
751 Descriptor.ContainerString = getContainerString(Context, Loop, ContainerExpr);
752
753 if (FixerKind == LFK_Iterator)
754 getIteratorLoopQualifiers(Context, Nodes, Descriptor);
755 else
756 getArrayLoopQualifiers(Context, Nodes, ContainerExpr, Usages, Descriptor);
757 }
758
759 /// Check some of the conditions that must be met for the loop to be
760 /// convertible.
761 bool LoopConvertCheck::isConvertible(ASTContext *Context,
762 const ast_matchers::BoundNodes &Nodes,
763 const ForStmt *Loop,
764 LoopFixerKind FixerKind) {
765 // If we already modified the range of this for loop, don't do any further
766 // updates on this iteration.
767 if (TUInfo->getReplacedVars().count(Loop))
768 return false;
769
770 // Check that we have exactly one index variable and at most one end variable.
771 const auto *LoopVar = Nodes.getNodeAs<VarDecl>(IncrementVarName);
772 const auto *CondVar = Nodes.getNodeAs<VarDecl>(ConditionVarName);
773 const auto *InitVar = Nodes.getNodeAs<VarDecl>(InitVarName);
774 if (!areSameVariable(LoopVar, CondVar) || !areSameVariable(LoopVar, InitVar))
775 return false;
776 const auto *EndVar = Nodes.getNodeAs<VarDecl>(EndVarName);
777 const auto *ConditionEndVar = Nodes.getNodeAs<VarDecl>(ConditionEndVarName);
778 if (EndVar && !areSameVariable(EndVar, ConditionEndVar))
779 return false;
780
781 // FIXME: Try to put most of this logic inside a matcher.
782 if (FixerKind == LFK_Iterator) {
783 QualType InitVarType = InitVar->getType();
784 QualType CanonicalInitVarType = InitVarType.getCanonicalType();
785
786 const auto *BeginCall = Nodes.getNodeAs<CXXMemberCallExpr>(BeginCallName);
787 assert(BeginCall && "Bad Callback. No begin call expression");
788 QualType CanonicalBeginType =
789 BeginCall->getMethodDecl()->getReturnType().getCanonicalType();
790 if (CanonicalBeginType->isPointerType() &&
791 CanonicalInitVarType->isPointerType()) {
792 // If the initializer and the variable are both pointers check if the
793 // un-qualified pointee types match, otherwise we don't use auto.
794 if (!Context->hasSameUnqualifiedType(
795 CanonicalBeginType->getPointeeType(),
796 CanonicalInitVarType->getPointeeType()))
797 return false;
798 }
799 } else if (FixerKind == LFK_PseudoArray) {
800 // This call is required to obtain the container.
801 const auto *EndCall = Nodes.getNodeAs<CXXMemberCallExpr>(EndCallName);
802 if (!EndCall || !dyn_cast<MemberExpr>(EndCall->getCallee()))
803 return false;
804 }
805 return true;
806 }
807
808 void LoopConvertCheck::check(const MatchFinder::MatchResult &Result) {
809 const BoundNodes &Nodes = Result.Nodes;
810 Confidence ConfidenceLevel(Confidence::CL_Safe);
811 ASTContext *Context = Result.Context;
812
813 const ForStmt *Loop;
814 LoopFixerKind FixerKind;
815 RangeDescriptor Descriptor;
816
817 if ((Loop = Nodes.getNodeAs<ForStmt>(LoopNameArray))) {
818 FixerKind = LFK_Array;
819 } else if ((Loop = Nodes.getNodeAs<ForStmt>(LoopNameIterator))) {
820 FixerKind = LFK_Iterator;
821 } else {
822 Loop = Nodes.getNodeAs<ForStmt>(LoopNamePseudoArray);
823 assert(Loop && "Bad Callback. No for statement");
824 FixerKind = LFK_PseudoArray;
825 }
826
827 if (!isConvertible(Context, Nodes, Loop, FixerKind))
828 return;
829
830 const auto *LoopVar = Nodes.getNodeAs<VarDecl>(IncrementVarName);
831 const auto *EndVar = Nodes.getNodeAs<VarDecl>(EndVarName);
832
833 // If the loop calls end()/size() after each iteration, lower our confidence
834 // level.
835 if (FixerKind != LFK_Array && !EndVar)
836 ConfidenceLevel.lowerTo(Confidence::CL_Reasonable);
837
838 // If the end comparison isn't a variable, we can try to work with the
839 // expression the loop variable is being tested against instead.
840 const auto *EndCall = Nodes.getNodeAs<CXXMemberCallExpr>(EndCallName);
841 const auto *BoundExpr = Nodes.getNodeAs<Expr>(ConditionBoundName);
842
843 // Find container expression of iterators and pseudoarrays, and determine if
844 // this expression needs to be dereferenced to obtain the container.
845 // With array loops, the container is often discovered during the
846 // ForLoopIndexUseVisitor traversal.
847 const Expr *ContainerExpr = nullptr;
848 if (FixerKind == LFK_Iterator) {
849 ContainerExpr = findContainer(Context, LoopVar->getInit(),
850 EndVar ? EndVar->getInit() : EndCall,
851 &Descriptor.ContainerNeedsDereference);
852 } else if (FixerKind == LFK_PseudoArray) {
853 ContainerExpr = EndCall->getImplicitObjectArgument();
854 Descriptor.ContainerNeedsDereference =
855 dyn_cast<MemberExpr>(EndCall->getCallee())->isArrow();
856 }
857
858 // We must know the container or an array length bound.
859 if (!ContainerExpr && !BoundExpr)
860 return;
861
862 ForLoopIndexUseVisitor Finder(Context, LoopVar, EndVar, ContainerExpr,
863 BoundExpr,
864 Descriptor.ContainerNeedsDereference);
865
866 // Find expressions and variables on which the container depends.
867 if (ContainerExpr) {
868 ComponentFinderASTVisitor ComponentFinder;
869 ComponentFinder.findExprComponents(ContainerExpr->IgnoreParenImpCasts());
870 Finder.addComponents(ComponentFinder.getComponents());
871 }
872
873 // Find usages of the loop index. If they are not used in a convertible way,
874 // stop here.
875 if (!Finder.findAndVerifyUsages(Loop->getBody()))
876 return;
877 ConfidenceLevel.lowerTo(Finder.getConfidenceLevel());
878
879 // Obtain the container expression, if we don't have it yet.
880 if (FixerKind == LFK_Array) {
881 ContainerExpr = Finder.getContainerIndexed()->IgnoreParenImpCasts();
882
883 // Very few loops are over expressions that generate arrays rather than
884 // array variables. Consider loops over arrays that aren't just represented
885 // by a variable to be risky conversions.
886 if (!getReferencedVariable(ContainerExpr) &&
887 !isDirectMemberExpr(ContainerExpr))
888 ConfidenceLevel.lowerTo(Confidence::CL_Risky);
889 }
890
891 // Find out which qualifiers we have to use in the loop range.
892 const UsageResult &Usages = Finder.getUsages();
893 determineRangeDescriptor(Context, Nodes, Loop, FixerKind, ContainerExpr,
894 Usages, Descriptor);
895
896 // Ensure that we do not try to move an expression dependent on a local
897 // variable declared inside the loop outside of it.
898 // FIXME: Determine when the external dependency isn't an expression converted
899 // by another loop.
900 TUInfo->getParentFinder().gatherAncestors(*Context);
901 DependencyFinderASTVisitor DependencyFinder(
902 &TUInfo->getParentFinder().getStmtToParentStmtMap(),
903 &TUInfo->getParentFinder().getDeclToParentStmtMap(),
904 &TUInfo->getReplacedVars(), Loop);
905
906 if (DependencyFinder.dependsOnInsideVariable(ContainerExpr) ||
907 Descriptor.ContainerString.empty() || Usages.empty() ||
908 ConfidenceLevel.getLevel() < MinConfidence)
909 return;
910
911 doConversion(Context, LoopVar, getReferencedVariable(ContainerExpr), Usages,
912 Finder.getAliasDecl(), Finder.aliasUseRequired(),
913 Finder.aliasFromForInit(), Loop, Descriptor);
914 }
915
916 } // namespace modernize
917 } // namespace tidy
918 } // namespace clang
clang::tidy::modernize::DerefByRefResultName
static const char DerefByRefResultName[]
Definition: LoopConvertCheck.cpp:44
clang::tidy::modernize::InitToZeroMatcher
static const DeclarationMatcher InitToZeroMatcher()
Definition: LoopConvertCheck.cpp:54
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::modernize::ForLoopIndexUseVisitor::getConfidenceLevel
Confidence::Level getConfidenceLevel() const
Accessor for ConfidenceLevel.
Definition: LoopConvertUtils.h:322
clang::tidy::modernize::ForLoopIndexUseVisitor
Discover usages of expressions consisting of index or iterator access.
Definition: LoopConvertUtils.h:283
llvm
Some operations such as code completion produce a set of candidates.
Definition: YAMLGenerator.cpp:28
clang::tidy::modernize::makeIteratorLoopMatcher
StatementMatcher makeIteratorLoopMatcher()
The matcher used for iterator-based for loops.
Definition: LoopConvertCheck.cpp:127
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:472
clang::tidy::modernize::ConditionVarName
static const char ConditionVarName[]
Definition: LoopConvertCheck.cpp:36
clang::tidy::modernize::getContainerFromBeginEndCall
static const Expr * getContainerFromBeginEndCall(const Expr *Init, bool IsBegin, bool *IsArrow)
Determine whether Init appears to be an initializing an iterator.
Definition: LoopConvertCheck.cpp:304
clang::tidy::modernize::makeArrayLoopMatcher
StatementMatcher makeArrayLoopMatcher()
The matcher for loops over arrays.
Definition: LoopConvertCheck.cpp:82
clang::tidy::modernize::UsageResult
llvm::SmallVector< Usage, 8 > UsageResult
Definition: LoopConvertUtils.h:270
clang::tidy::modernize::IntegerComparisonMatcher
static const StatementMatcher IntegerComparisonMatcher()
Definition: LoopConvertCheck.cpp:49
clang::tidy::modernize::Usage::Expression
const Expr * Expression
Definition: LoopConvertUtils.h:228
clang::tidy::modernize::EndCallName
static const char EndCallName[]
Definition: LoopConvertCheck.cpp:40
clang::tidy::modernize::Usage::Kind
UsageKind Kind
Definition: LoopConvertUtils.h:230
clang::tidy::modernize::Usage::UK_CaptureByCopy
Definition: LoopConvertUtils.h:223
clang::tidy::modernize::Confidence
A class to encapsulate lowering of the tool&#39;s confidence level.
Definition: LoopConvertUtils.h:242
clang::tidy::modernize::ForLoopIndexUseVisitor::getContainerIndexed
const Expr * getContainerIndexed() const
Get the container indexed by IndexVar, if any.
Definition: LoopConvertUtils.h:315
clang::tidy::modernize::LFK_PseudoArray
Definition: LoopConvertUtils.h:29
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:109
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidyCheck.h:47
clang::tidy::modernize::ForLoopIndexUseVisitor::aliasUseRequired
bool aliasUseRequired() const
Indicates if the alias declaration was in a place where it cannot simply be removed but rather replac...
Definition: LoopConvertUtils.h:330
clang::tidy::modernize::digThroughConstructors
const Expr * digThroughConstructors(const Expr *E)
Look through conversion/copy constructors to find the explicit initialization expression, returning it is found.
Definition: LoopConvertUtils.cpp:168
clang::tidy::ClangTidyCheck::getLangOpts
const LangOptions & getLangOpts() const
Returns the language options from the context.
Definition: ClangTidyCheck.h:188
clang::tidy::modernize::findContainer
static const Expr * findContainer(ASTContext *Context, const Expr *BeginExpr, const Expr *EndExpr, bool *ContainerNeedsDereference)
Determines the container whose begin() and end() functions are called for an iterator-based loop...
Definition: LoopConvertCheck.cpp:334
clang::tidy::modernize::InitVarName
static const char InitVarName[]
Definition: LoopConvertCheck.cpp:38
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:373
clang::tidy::modernize::EndVarName
static const char EndVarName[]
Definition: LoopConvertCheck.cpp:42
clang::tidy::modernize::ForLoopIndexUseVisitor::aliasFromForInit
bool aliasFromForInit() const
Indicates if the alias declaration came from the init clause of a nested for loop.
Definition: LoopConvertUtils.h:335
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidyCheck.h:184
clang::tidy::modernize::Usage::Range
SourceRange Range
Definition: LoopConvertUtils.h:233
clang::tidy::modernize::LoopConvertCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: LoopConvertCheck.cpp:482
clang::tidy::modernize::AnyType
static const TypeMatcher AnyType()
Definition: LoopConvertCheck.cpp:47
clang::tidy::modernize::getDeclRef
const DeclRefExpr * getDeclRef(const Expr *E)
Returns the DeclRefExpr represented by E, or NULL if there isn&#39;t one.
Definition: LoopConvertUtils.cpp:198
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:91
clang::tidy::modernize::VariableNamer::createIndexName
std::string createIndexName()
Generate a new index name.
Definition: LoopConvertUtils.cpp:843
clang::tidy::modernize::ComponentFinderASTVisitor::getComponents
const ComponentVector & getComponents()
Accessor for Components.
Definition: LoopConvertUtils.h:96
clang::tidy::modernize::Confidence::getLevel
Level getLevel() const
Return the internal confidence level.
Definition: LoopConvertUtils.h:263
clang::tidy::modernize::areSameVariable
bool areSameVariable(const ValueDecl *First, const ValueDecl *Second)
Returns true when two ValueDecls are the same variable.
Definition: LoopConvertUtils.cpp:203
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:427
clang::tidy::modernize::ConditionBoundName
static const char ConditionBoundName[]
Definition: LoopConvertCheck.cpp:35
clang::tidy::modernize::LFK_Array
Definition: LoopConvertUtils.h:29
clang::tidy::modernize::VariableNamer
Create names for generated variables within a particular statement.
Definition: LoopConvertUtils.h:422
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:58
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:411
clang::tidy::modernize::IncrementVarName
static const char IncrementVarName[]
Definition: LoopConvertCheck.cpp:37
clang::tidy::modernize::areSameExpr
bool areSameExpr(ASTContext *Context, const Expr *First, const Expr *Second)
Returns true when two Exprs are equivalent.
Definition: LoopConvertUtils.cpp:187
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:392
Name
static constexpr llvm::StringLiteral Name
Definition: UppercaseLiteralSuffixCheck.cpp:27
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, std::string > OptionMap
Definition: ClangTidyOptions.h:97
clang::tidy::modernize::ConditionEndVarName
static const char ConditionEndVarName[]
Definition: LoopConvertCheck.cpp:41
clang::tidy::modernize::LoopNameArray
static const char LoopNameArray[]
Definition: LoopConvertCheck.cpp:32
clang::tidy::modernize::Confidence::CL_Safe
Definition: LoopConvertUtils.h:252
clang::clangd::getTokenRange
llvm::Optional< Range > getTokenRange(const SourceManager &SM, const LangOptions &LangOpts, SourceLocation TokLoc)
Returns the taken range at TokLoc.
Definition: SourceCode.cpp:227
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:359
clang::tidy::modernize::DerefByValueResultName
static const char DerefByValueResultName[]
Definition: LoopConvertCheck.cpp:43
clang::tidy::modernize::TUTrackingInfo
Definition: LoopConvertUtils.h:400
clang::tidy::modernize::IncrementVarMatcher
static const StatementMatcher IncrementVarMatcher()
Definition: LoopConvertCheck.cpp:60
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:808
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:383
Offset
size_t Offset
Definition: CodeComplete.cpp:1022
clang::tidy::modernize::LoopFixerKind
LoopFixerKind
Definition: LoopConvertUtils.h:29
clang::tidy::modernize::LoopNamePseudoArray
static const char LoopNamePseudoArray[]
Definition: LoopConvertCheck.cpp:34
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::tidy::modernize::ForLoopIndexUseVisitor::findAndVerifyUsages
bool findAndVerifyUsages(const Stmt *Body)
Finds all uses of IndexVar in Body, placing all usages in Usages, and returns true if IndexVar was on...
Definition: LoopConvertUtils.cpp:465
clang::tidy::modernize::Usage
The information needed to describe a valid convertible usage of an array index or iterator...
Definition: LoopConvertUtils.h:205
Range
CharSourceRange Range
SourceRange for the file name.
Definition: IncludeOrderCheck.cpp:38
clang::tidy::modernize::ForLoopIndexUseVisitor::addComponents
void addComponents(const ComponentVector &Components)
Add a set of components that we should consider relevant to the container.
Definition: LoopConvertUtils.cpp:470
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:258
clang::tidy::modernize::BeginCallName
static const char BeginCallName[]
Definition: LoopConvertCheck.cpp:39
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:77
E
const Expr * E
Definition: AvoidBindCheck.cpp:82
LoopConvertCheck.h
clang::tidy::modernize::LFK_Iterator
Definition: LoopConvertUtils.h:29
clang::tidy::modernize::ComponentFinderASTVisitor
Class used to find the variables and member expressions on which an arbitrary expression depends...
Definition: LoopConvertUtils.h:85
clang::tidy::modernize::LoopNameIterator
static const char LoopNameIterator[]
Definition: LoopConvertCheck.cpp:33
clang::tidy::modernize::containerIsConst
static bool containerIsConst(const Expr *ContainerExpr, bool Dereference)
Returns true if the container is const-qualified.
Definition: LoopConvertCheck.cpp:436
clang::tidy::modernize::makePseudoArrayLoopMatcher
StatementMatcher makePseudoArrayLoopMatcher()
The matcher used for array-like containers (pseudoarrays).
Definition: LoopConvertCheck.cpp:235
Type
NodeType Type
Definition: HTMLGenerator.cpp:73
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
Definition: ClangTidyCheck.cpp:21
clang::tidy::modernize::Confidence::CL_Risky
Definition: LoopConvertUtils.h:246
clang::tidy::modernize::ForLoopIndexUseVisitor::getUsages
const UsageResult & getUsages() const
Accessor for Usages.
Definition: LoopConvertUtils.h:309
clang::tidy::modernize::Usage::UK_MemberThroughArrow
Definition: LoopConvertUtils.h:220
clang::tidy::modernize::ForLoopIndexUseVisitor::getAliasDecl
const DeclStmt * getAliasDecl() const
Returns the statement declaring the variable created as an alias for the loop element, if any.
Definition: LoopConvertUtils.h:319
clang::tidy::modernize::Confidence::CL_Reasonable
Definition: LoopConvertUtils.h:249