Bug Summary

File:build/source/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp
Warning:line 43, column 5
Address of stack memory associated with local variable 'InnerMatcher' is still referred to by a temporary object on the stack upon returning to the caller. This will be a dangling reference

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name UseNullptrCheck.cpp -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/source/build-llvm/tools/clang/stage2-bins -resource-dir /usr/lib/llvm-17/lib/clang/17 -D CLANG_REPOSITORY_STRING="++20230510111145+7df43bdb42ae-1~exp1~20230510111303.1288" -D _DEBUG -D _GLIBCXX_ASSERTIONS -D _GNU_SOURCE -D _LIBCPP_ENABLE_ASSERTIONS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I tools/clang/tools/extra/clang-tidy/modernize -I /build/source/clang-tools-extra/clang-tidy/modernize -I tools/clang/tools/extra/clang-tidy -I /build/source/clang/include -I tools/clang/include -I include -I /build/source/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-17/lib/clang/17/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fmacro-prefix-map=/build/source/= -fcoverage-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fcoverage-prefix-map=/build/source/= -source-date-epoch 1683717183 -O2 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -Wno-misleading-indentation -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=/build/source/build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/source/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2023-05-10-133810-16478-1 -x c++ /build/source/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp
1//===--- UseNullptrCheck.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 "UseNullptrCheck.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/AST/RecursiveASTVisitor.h"
12#include "clang/ASTMatchers/ASTMatchFinder.h"
13#include "clang/Lex/Lexer.h"
14
15using namespace clang;
16using namespace clang::ast_matchers;
17using namespace llvm;
18
19namespace clang::tidy::modernize {
20namespace {
21
22const char CastSequence[] = "sequence";
23
24AST_MATCHER(Type, sugaredNullptrType)namespace internal { class matcher_sugaredNullptrTypeMatcher :
public ::clang::ast_matchers::internal::MatcherInterface<
Type> { public: explicit matcher_sugaredNullptrTypeMatcher
() = default; bool matches(const Type &Node, ::clang::ast_matchers
::internal::ASTMatchFinder *Finder, ::clang::ast_matchers::internal
::BoundNodesTreeBuilder *Builder) const override; }; } inline
::clang::ast_matchers::internal::Matcher<Type> sugaredNullptrType
() { return ::clang::ast_matchers::internal::makeMatcher( new
internal::matcher_sugaredNullptrTypeMatcher()); } inline bool
internal::matcher_sugaredNullptrTypeMatcher::matches( const Type
&Node, ::clang::ast_matchers::internal::ASTMatchFinder *
Finder, ::clang::ast_matchers::internal::BoundNodesTreeBuilder
*Builder) const {
25 const Type *DesugaredType = Node.getUnqualifiedDesugaredType();
26 if (const auto *BT = dyn_cast<BuiltinType>(DesugaredType))
27 return BT->getKind() == BuiltinType::NullPtr;
28 return false;
29}
30
31/// Create a matcher that finds implicit casts as well as the head of a
32/// sequence of zero or more nested explicit casts that have an implicit cast
33/// to null within.
34/// Finding sequences of explicit casts is necessary so that an entire sequence
35/// can be replaced instead of just the inner-most implicit cast.
36StatementMatcher makeCastSequenceMatcher() {
37 StatementMatcher ImplicitCastToNull = implicitCastExpr(
38 anyOf(hasCastKind(CK_NullToPointer), hasCastKind(CK_NullToMemberPointer)),
39 unless(hasImplicitDestinationType(qualType(substTemplateTypeParmType()))),
40 unless(hasSourceExpression(hasType(sugaredNullptrType()))));
41
42 auto IsOrHasDescendant = [](auto InnerMatcher) {
43 return anyOf(InnerMatcher, hasDescendant(InnerMatcher));
3
←
Address of stack memory associated with local variable 'InnerMatcher' is still referred to by a temporary object on the stack upon returning to the caller. This will be a dangling reference
44 };
45
46 return traverse(
47 TK_AsIs,
48 anyOf(castExpr(anyOf(ImplicitCastToNull,
49 explicitCastExpr(hasDescendant(ImplicitCastToNull))),
50 unless(hasAncestor(explicitCastExpr())),
51 unless(hasAncestor(cxxRewrittenBinaryOperator())))
52 .bind(CastSequence),
53 cxxRewrittenBinaryOperator(
54 // Match rewritten operators, but verify (in the check method)
55 // that if an implicit cast is found, it is not from another
56 // nested rewritten operator.
57 expr().bind("matchBinopOperands"),
58 hasEitherOperand(IsOrHasDescendant(
2
←
Calling 'operator()'
→
59 implicitCastExpr(
60 ImplicitCastToNull,
61 hasAncestor(cxxRewrittenBinaryOperator().bind(
62 "checkBinopOperands")))
63 .bind(CastSequence))),
64 // Skip defaulted comparison operators.
65 unless(hasAncestor(functionDecl(isDefaulted()))))));
66}
67
68bool isReplaceableRange(SourceLocation StartLoc, SourceLocation EndLoc,
69 const SourceManager &SM) {
70 return SM.isWrittenInSameFile(StartLoc, EndLoc);
71}
72
73/// Replaces the provided range with the text "nullptr", but only if
74/// the start and end location are both in main file.
75/// Returns true if and only if a replacement was made.
76void replaceWithNullptr(ClangTidyCheck &Check, SourceManager &SM,
77 SourceLocation StartLoc, SourceLocation EndLoc) {
78 CharSourceRange Range(SourceRange(StartLoc, EndLoc), true);
79 // Add a space if nullptr follows an alphanumeric character. This happens
80 // whenever there is an c-style explicit cast to nullptr not surrounded by
81 // parentheses and right beside a return statement.
82 SourceLocation PreviousLocation = StartLoc.getLocWithOffset(-1);
83 bool NeedsSpace = isAlphanumeric(*SM.getCharacterData(PreviousLocation));
84 Check.diag(Range.getBegin(), "use nullptr") << FixItHint::CreateReplacement(
85 Range, NeedsSpace ? " nullptr" : "nullptr");
86}
87
88/// Returns the name of the outermost macro.
89///
90/// Given
91/// \code
92/// #define MY_NULL NULL
93/// \endcode
94/// If \p Loc points to NULL, this function will return the name MY_NULL.
95StringRef getOutermostMacroName(SourceLocation Loc, const SourceManager &SM,
96 const LangOptions &LO) {
97 assert(Loc.isMacroID())(static_cast <bool> (Loc.isMacroID()) ? void (0) : __assert_fail
("Loc.isMacroID()", "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 97, __extension__ __PRETTY_FUNCTION__));
98 SourceLocation OutermostMacroLoc;
99
100 while (Loc.isMacroID()) {
101 OutermostMacroLoc = Loc;
102 Loc = SM.getImmediateMacroCallerLoc(Loc);
103 }
104
105 return Lexer::getImmediateMacroName(OutermostMacroLoc, SM, LO);
106}
107
108/// RecursiveASTVisitor for ensuring all nodes rooted at a given AST
109/// subtree that have file-level source locations corresponding to a macro
110/// argument have implicit NullTo(Member)Pointer nodes as ancestors.
111class MacroArgUsageVisitor : public RecursiveASTVisitor<MacroArgUsageVisitor> {
112public:
113 MacroArgUsageVisitor(SourceLocation CastLoc, const SourceManager &SM)
114 : CastLoc(CastLoc), SM(SM), Visited(false), CastFound(false),
115 InvalidFound(false) {
116 assert(CastLoc.isFileID())(static_cast <bool> (CastLoc.isFileID()) ? void (0) : __assert_fail
("CastLoc.isFileID()", "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 116, __extension__ __PRETTY_FUNCTION__));
117 }
118
119 bool TraverseStmt(Stmt *S) {
120 bool VisitedPreviously = Visited;
121
122 if (!RecursiveASTVisitor<MacroArgUsageVisitor>::TraverseStmt(S))
123 return false;
124
125 // The point at which VisitedPreviously is false and Visited is true is the
126 // root of a subtree containing nodes whose locations match CastLoc. It's
127 // at this point we test that the Implicit NullTo(Member)Pointer cast was
128 // found or not.
129 if (!VisitedPreviously) {
130 if (Visited && !CastFound) {
131 // Found nodes with matching SourceLocations but didn't come across a
132 // cast. This is an invalid macro arg use. Can stop traversal
133 // completely now.
134 InvalidFound = true;
135 return false;
136 }
137 // Reset state as we unwind back up the tree.
138 CastFound = false;
139 Visited = false;
140 }
141 return true;
142 }
143
144 bool VisitStmt(Stmt *S) {
145 if (SM.getFileLoc(S->getBeginLoc()) != CastLoc)
146 return true;
147 Visited = true;
148
149 const ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(S);
150 if (Cast && (Cast->getCastKind() == CK_NullToPointer ||
151 Cast->getCastKind() == CK_NullToMemberPointer))
152 CastFound = true;
153
154 return true;
155 }
156
157 bool TraverseInitListExpr(InitListExpr *S) {
158 // Only go through the semantic form of the InitListExpr, because
159 // ImplicitCast might not appear in the syntactic form, and this results in
160 // finding usages of the macro argument that don't have a ImplicitCast as an
161 // ancestor (thus invalidating the replacement) when they actually have.
162 return RecursiveASTVisitor<MacroArgUsageVisitor>::
163 TraverseSynOrSemInitListExpr(
164 S->isSemanticForm() ? S : S->getSemanticForm());
165 }
166
167 bool foundInvalid() const { return InvalidFound; }
168
169private:
170 SourceLocation CastLoc;
171 const SourceManager &SM;
172
173 bool Visited;
174 bool CastFound;
175 bool InvalidFound;
176};
177
178/// Looks for implicit casts as well as sequences of 0 or more explicit
179/// casts with an implicit null-to-pointer cast within.
180///
181/// The matcher this visitor is used with will find a single implicit cast or a
182/// top-most explicit cast (i.e. it has no explicit casts as an ancestor) where
183/// an implicit cast is nested within. However, there is no guarantee that only
184/// explicit casts exist between the found top-most explicit cast and the
185/// possibly more than one nested implicit cast. This visitor finds all cast
186/// sequences with an implicit cast to null within and creates a replacement
187/// leaving the outermost explicit cast unchanged to avoid introducing
188/// ambiguities.
189class CastSequenceVisitor : public RecursiveASTVisitor<CastSequenceVisitor> {
190public:
191 CastSequenceVisitor(ASTContext &Context, ArrayRef<StringRef> NullMacros,
192 ClangTidyCheck &Check)
193 : SM(Context.getSourceManager()), Context(Context),
194 NullMacros(NullMacros), Check(Check), FirstSubExpr(nullptr),
195 PruneSubtree(false) {}
196
197 bool TraverseStmt(Stmt *S) {
198 // Stop traversing down the tree if requested.
199 if (PruneSubtree) {
200 PruneSubtree = false;
201 return true;
202 }
203 return RecursiveASTVisitor<CastSequenceVisitor>::TraverseStmt(S);
204 }
205
206 // Only VisitStmt is overridden as we shouldn't find other base AST types
207 // within a cast expression.
208 bool VisitStmt(Stmt *S) {
209 auto *C = dyn_cast<CastExpr>(S);
210 // Catch the castExpr inside cxxDefaultArgExpr.
211 if (auto *E = dyn_cast<CXXDefaultArgExpr>(S)) {
212 C = dyn_cast<CastExpr>(E->getExpr());
213 FirstSubExpr = nullptr;
214 }
215 if (!C) {
216 FirstSubExpr = nullptr;
217 return true;
218 }
219
220 auto* CastSubExpr = C->getSubExpr()->IgnoreParens();
221 // Ignore cast expressions which cast nullptr literal.
222 if (isa<CXXNullPtrLiteralExpr>(CastSubExpr)) {
223 return true;
224 }
225
226 if (!FirstSubExpr)
227 FirstSubExpr = CastSubExpr;
228
229 if (C->getCastKind() != CK_NullToPointer &&
230 C->getCastKind() != CK_NullToMemberPointer) {
231 return true;
232 }
233
234 SourceLocation StartLoc = FirstSubExpr->getBeginLoc();
235 SourceLocation EndLoc = FirstSubExpr->getEndLoc();
236
237 // If the location comes from a macro arg expansion, *all* uses of that
238 // arg must be checked to result in NullTo(Member)Pointer casts.
239 //
240 // If the location comes from a macro body expansion, check to see if its
241 // coming from one of the allowed 'NULL' macros.
242 if (SM.isMacroArgExpansion(StartLoc) && SM.isMacroArgExpansion(EndLoc)) {
243 SourceLocation FileLocStart = SM.getFileLoc(StartLoc),
244 FileLocEnd = SM.getFileLoc(EndLoc);
245 SourceLocation ImmediateMacroArgLoc, MacroLoc;
246 // Skip NULL macros used in macro.
247 if (!getMacroAndArgLocations(StartLoc, ImmediateMacroArgLoc, MacroLoc) ||
248 ImmediateMacroArgLoc != FileLocStart)
249 return skipSubTree();
250
251 if (isReplaceableRange(FileLocStart, FileLocEnd, SM) &&
252 allArgUsesValid(C)) {
253 replaceWithNullptr(Check, SM, FileLocStart, FileLocEnd);
254 }
255 return true;
256 }
257
258 if (SM.isMacroBodyExpansion(StartLoc) && SM.isMacroBodyExpansion(EndLoc)) {
259 StringRef OutermostMacroName =
260 getOutermostMacroName(StartLoc, SM, Context.getLangOpts());
261
262 // Check to see if the user wants to replace the macro being expanded.
263 if (!llvm::is_contained(NullMacros, OutermostMacroName))
264 return skipSubTree();
265
266 StartLoc = SM.getFileLoc(StartLoc);
267 EndLoc = SM.getFileLoc(EndLoc);
268 }
269
270 if (!isReplaceableRange(StartLoc, EndLoc, SM)) {
271 return skipSubTree();
272 }
273 replaceWithNullptr(Check, SM, StartLoc, EndLoc);
274
275 return true;
276 }
277
278private:
279 bool skipSubTree() {
280 PruneSubtree = true;
281 return true;
282 }
283
284 /// Tests that all expansions of a macro arg, one of which expands to
285 /// result in \p CE, yield NullTo(Member)Pointer casts.
286 bool allArgUsesValid(const CastExpr *CE) {
287 SourceLocation CastLoc = CE->getBeginLoc();
288
289 // Step 1: Get location of macro arg and location of the macro the arg was
290 // provided to.
291 SourceLocation ArgLoc, MacroLoc;
292 if (!getMacroAndArgLocations(CastLoc, ArgLoc, MacroLoc))
293 return false;
294
295 // Step 2: Find the first ancestor that doesn't expand from this macro.
296 DynTypedNode ContainingAncestor;
297 if (!findContainingAncestor(DynTypedNode::create<Stmt>(*CE), MacroLoc,
298 ContainingAncestor))
299 return false;
300
301 // Step 3:
302 // Visit children of this containing parent looking for the least-descended
303 // nodes of the containing parent which are macro arg expansions that expand
304 // from the given arg location.
305 // Visitor needs: arg loc.
306 MacroArgUsageVisitor ArgUsageVisitor(SM.getFileLoc(CastLoc), SM);
307 if (const auto *D = ContainingAncestor.get<Decl>())
308 ArgUsageVisitor.TraverseDecl(const_cast<Decl *>(D));
309 else if (const auto *S = ContainingAncestor.get<Stmt>())
310 ArgUsageVisitor.TraverseStmt(const_cast<Stmt *>(S));
311 else
312 llvm_unreachable("Unhandled ContainingAncestor node type")::llvm::llvm_unreachable_internal("Unhandled ContainingAncestor node type"
, "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 312);
313
314 return !ArgUsageVisitor.foundInvalid();
315 }
316
317 /// Given the SourceLocation for a macro arg expansion, finds the
318 /// non-macro SourceLocation of the macro the arg was passed to and the
319 /// non-macro SourceLocation of the argument in the arg list to that macro.
320 /// These results are returned via \c MacroLoc and \c ArgLoc respectively.
321 /// These values are undefined if the return value is false.
322 ///
323 /// \returns false if one of the returned SourceLocations would be a
324 /// SourceLocation pointing within the definition of another macro.
325 bool getMacroAndArgLocations(SourceLocation Loc, SourceLocation &ArgLoc,
326 SourceLocation &MacroLoc) {
327 assert(Loc.isMacroID() && "Only reasonable to call this on macros")(static_cast <bool> (Loc.isMacroID() && "Only reasonable to call this on macros"
) ? void (0) : __assert_fail ("Loc.isMacroID() && \"Only reasonable to call this on macros\""
, "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 327, __extension__ __PRETTY_FUNCTION__));
328
329 ArgLoc = Loc;
330
331 // Find the location of the immediate macro expansion.
332 while (true) {
333 std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(ArgLoc);
334 const SrcMgr::SLocEntry *E = &SM.getSLocEntry(LocInfo.first);
335 const SrcMgr::ExpansionInfo &Expansion = E->getExpansion();
336
337 SourceLocation OldArgLoc = ArgLoc;
338 ArgLoc = Expansion.getExpansionLocStart();
339 if (!Expansion.isMacroArgExpansion()) {
340 if (!MacroLoc.isFileID())
341 return false;
342
343 StringRef Name =
344 Lexer::getImmediateMacroName(OldArgLoc, SM, Context.getLangOpts());
345 return llvm::is_contained(NullMacros, Name);
346 }
347
348 MacroLoc = SM.getExpansionRange(ArgLoc).getBegin();
349
350 ArgLoc = Expansion.getSpellingLoc().getLocWithOffset(LocInfo.second);
351 if (ArgLoc.isFileID())
352 return true;
353
354 // If spelling location resides in the same FileID as macro expansion
355 // location, it means there is no inner macro.
356 FileID MacroFID = SM.getFileID(MacroLoc);
357 if (SM.isInFileID(ArgLoc, MacroFID)) {
358 // Don't transform this case. If the characters that caused the
359 // null-conversion come from within a macro, they can't be changed.
360 return false;
361 }
362 }
363
364 llvm_unreachable("getMacroAndArgLocations")::llvm::llvm_unreachable_internal("getMacroAndArgLocations", "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 364);
365 }
366
367 /// Tests if TestMacroLoc is found while recursively unravelling
368 /// expansions starting at TestLoc. TestMacroLoc.isFileID() must be true.
369 /// Implementation is very similar to getMacroAndArgLocations() except in this
370 /// case, it's not assumed that TestLoc is expanded from a macro argument.
371 /// While unravelling expansions macro arguments are handled as with
372 /// getMacroAndArgLocations() but in this function macro body expansions are
373 /// also handled.
374 ///
375 /// False means either:
376 /// - TestLoc is not from a macro expansion.
377 /// - TestLoc is from a different macro expansion.
378 bool expandsFrom(SourceLocation TestLoc, SourceLocation TestMacroLoc) {
379 if (TestLoc.isFileID()) {
380 return false;
381 }
382
383 SourceLocation Loc = TestLoc, MacroLoc;
384
385 while (true) {
386 std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(Loc);
387 const SrcMgr::SLocEntry *E = &SM.getSLocEntry(LocInfo.first);
388 const SrcMgr::ExpansionInfo &Expansion = E->getExpansion();
389
390 Loc = Expansion.getExpansionLocStart();
391
392 if (!Expansion.isMacroArgExpansion()) {
393 if (Loc.isFileID()) {
394 return Loc == TestMacroLoc;
395 }
396 // Since Loc is still a macro ID and it's not an argument expansion, we
397 // don't need to do the work of handling an argument expansion. Simply
398 // keep recursively expanding until we hit a FileID or a macro arg
399 // expansion or a macro arg expansion.
400 continue;
401 }
402
403 MacroLoc = SM.getImmediateExpansionRange(Loc).getBegin();
404 if (MacroLoc.isFileID() && MacroLoc == TestMacroLoc) {
405 // Match made.
406 return true;
407 }
408
409 Loc = Expansion.getSpellingLoc().getLocWithOffset(LocInfo.second);
410 if (Loc.isFileID()) {
411 // If we made it this far without finding a match, there is no match to
412 // be made.
413 return false;
414 }
415 }
416
417 llvm_unreachable("expandsFrom")::llvm::llvm_unreachable_internal("expandsFrom", "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 417);
418 }
419
420 /// Given a starting point \c Start in the AST, find an ancestor that
421 /// doesn't expand from the macro called at file location \c MacroLoc.
422 ///
423 /// \pre MacroLoc.isFileID()
424 /// \returns true if such an ancestor was found, false otherwise.
425 bool findContainingAncestor(DynTypedNode Start, SourceLocation MacroLoc,
426 DynTypedNode &Result) {
427 // Below we're only following the first parent back up the AST. This should
428 // be fine since for the statements we care about there should only be one
429 // parent, except for the case specified below.
430
431 assert(MacroLoc.isFileID())(static_cast <bool> (MacroLoc.isFileID()) ? void (0) : __assert_fail
("MacroLoc.isFileID()", "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 431, __extension__ __PRETTY_FUNCTION__));
432
433 while (true) {
434 const auto &Parents = Context.getParents(Start);
435 if (Parents.empty())
436 return false;
437 if (Parents.size() > 1) {
438 // If there are more than one parents, don't do the replacement unless
439 // they are InitListsExpr (semantic and syntactic form). In this case we
440 // can choose any one here, and the ASTVisitor will take care of
441 // traversing the right one.
442 for (const auto &Parent : Parents) {
443 if (!Parent.get<InitListExpr>())
444 return false;
445 }
446 }
447
448 const DynTypedNode &Parent = Parents[0];
449
450 SourceLocation Loc;
451 if (const auto *D = Parent.get<Decl>())
452 Loc = D->getBeginLoc();
453 else if (const auto *S = Parent.get<Stmt>())
454 Loc = S->getBeginLoc();
455
456 // TypeLoc and NestedNameSpecifierLoc are members of the parent map. Skip
457 // them and keep going up.
458 if (Loc.isValid()) {
459 if (!expandsFrom(Loc, MacroLoc)) {
460 Result = Parent;
461 return true;
462 }
463 }
464 Start = Parent;
465 }
466
467 llvm_unreachable("findContainingAncestor")::llvm::llvm_unreachable_internal("findContainingAncestor", "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 467);
468 }
469
470private:
471 SourceManager &SM;
472 ASTContext &Context;
473 ArrayRef<StringRef> NullMacros;
474 ClangTidyCheck &Check;
475 Expr *FirstSubExpr;
476 bool PruneSubtree;
477};
478
479} // namespace
480
481UseNullptrCheck::UseNullptrCheck(StringRef Name, ClangTidyContext *Context)
482 : ClangTidyCheck(Name, Context),
483 NullMacrosStr(Options.get("NullMacros", "NULL")) {
484 StringRef(NullMacrosStr).split(NullMacros, ",");
485}
486
487void UseNullptrCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
488 Options.store(Opts, "NullMacros", NullMacrosStr);
489}
490
491void UseNullptrCheck::registerMatchers(MatchFinder *Finder) {
492 Finder->addMatcher(makeCastSequenceMatcher(), this);
1
Calling 'makeCastSequenceMatcher'
→
493}
494
495void UseNullptrCheck::check(const MatchFinder::MatchResult &Result) {
496 const auto *NullCast = Result.Nodes.getNodeAs<CastExpr>(CastSequence);
497 assert(NullCast && "Bad Callback. No node provided")(static_cast <bool> (NullCast && "Bad Callback. No node provided"
) ? void (0) : __assert_fail ("NullCast && \"Bad Callback. No node provided\""
, "clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp"
, 497, __extension__ __PRETTY_FUNCTION__));
498
499 if (Result.Nodes.getNodeAs<CXXRewrittenBinaryOperator>(
500 "matchBinopOperands") !=
501 Result.Nodes.getNodeAs<CXXRewrittenBinaryOperator>("checkBinopOperands"))
502 return;
503
504 // Given an implicit null-ptr cast or an explicit cast with an implicit
505 // null-to-pointer cast within use CastSequenceVisitor to identify sequences
506 // of explicit casts that can be converted into 'nullptr'.
507 CastSequenceVisitor(*Result.Context, NullMacros, *this)
508 .TraverseStmt(const_cast<CastExpr *>(NullCast));
509}
510
511} // namespace clang::tidy::modernize