1//=- AnalysisBasedWarnings.cpp - Sema warnings based on libAnalysis -*- C++ -*-=//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines analysis_warnings::[Policy,Executor].
10// Together they are used by Sema to issue warnings based on inexpensive
11// static analysis algorithms in libAnalysis.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Sema/AnalysisBasedWarnings.h"
16#include "clang/AST/Decl.h"
17#include "clang/AST/DeclCXX.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/EvaluatedExprVisitor.h"
20#include "clang/AST/Expr.h"
21#include "clang/AST/ExprCXX.h"
22#include "clang/AST/ExprObjC.h"
23#include "clang/AST/OperationKinds.h"
24#include "clang/AST/ParentMap.h"
25#include "clang/AST/RecursiveASTVisitor.h"
26#include "clang/AST/StmtCXX.h"
27#include "clang/AST/StmtObjC.h"
28#include "clang/AST/StmtVisitor.h"
29#include "clang/AST/Type.h"
30#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
31#include "clang/Analysis/Analyses/CalledOnceCheck.h"
32#include "clang/Analysis/Analyses/Consumed.h"
33#include "clang/Analysis/Analyses/ReachableCode.h"
34#include "clang/Analysis/Analyses/ThreadSafety.h"
35#include "clang/Analysis/Analyses/UninitializedValues.h"
36#include "clang/Analysis/Analyses/UnsafeBufferUsage.h"
37#include "clang/Analysis/AnalysisDeclContext.h"
38#include "clang/Analysis/CFG.h"
39#include "clang/Analysis/CFGStmtMap.h"
40#include "clang/Basic/Diagnostic.h"
41#include "clang/Basic/DiagnosticSema.h"
42#include "clang/Basic/SourceLocation.h"
43#include "clang/Basic/SourceManager.h"
44#include "clang/Lex/Preprocessor.h"
45#include "clang/Sema/ScopeInfo.h"
46#include "clang/Sema/SemaInternal.h"
47#include "llvm/ADT/ArrayRef.h"
48#include "llvm/ADT/BitVector.h"
49#include "llvm/ADT/MapVector.h"
50#include "llvm/ADT/STLFunctionalExtras.h"
51#include "llvm/ADT/SmallString.h"
52#include "llvm/ADT/SmallVector.h"
53#include "llvm/ADT/StringRef.h"
54#include "llvm/Support/Casting.h"
55#include <algorithm>
56#include <deque>
57#include <iterator>
58#include <optional>
59
60using namespace clang;
61
62//===----------------------------------------------------------------------===//
63// Unreachable code analysis.
64//===----------------------------------------------------------------------===//
65
66namespace {
67 class UnreachableCodeHandler : public reachable_code::Callback {
68 Sema &S;
69 SourceRange PreviousSilenceableCondVal;
70
71 public:
72 UnreachableCodeHandler(Sema &s) : S(s) {}
73
74 void HandleUnreachable(reachable_code::UnreachableKind UK, SourceLocation L,
75 SourceRange SilenceableCondVal, SourceRange R1,
76 SourceRange R2, bool HasFallThroughAttr) override {
77 // If the diagnosed code is `[[fallthrough]];` and
78 // `-Wunreachable-code-fallthrough` is enabled, suppress `code will never
79 // be executed` warning to avoid generating diagnostic twice
80 if (HasFallThroughAttr &&
81 !S.getDiagnostics().isIgnored(diag::warn_unreachable_fallthrough_attr,
82 SourceLocation()))
83 return;
84
85 // Avoid reporting multiple unreachable code diagnostics that are
86 // triggered by the same conditional value.
87 if (PreviousSilenceableCondVal.isValid() &&
88 SilenceableCondVal.isValid() &&
89 PreviousSilenceableCondVal == SilenceableCondVal)
90 return;
91 PreviousSilenceableCondVal = SilenceableCondVal;
92
93 unsigned diag = diag::warn_unreachable;
94 switch (UK) {
95 case reachable_code::UK_Break:
96 diag = diag::warn_unreachable_break;
97 break;
98 case reachable_code::UK_Return:
99 diag = diag::warn_unreachable_return;
100 break;
101 case reachable_code::UK_Loop_Increment:
102 diag = diag::warn_unreachable_loop_increment;
103 break;
104 case reachable_code::UK_Other:
105 break;
106 }
107
108 S.Diag(Loc: L, DiagID: diag) << R1 << R2;
109
110 SourceLocation Open = SilenceableCondVal.getBegin();
111 if (Open.isValid()) {
112 SourceLocation Close = SilenceableCondVal.getEnd();
113 Close = S.getLocForEndOfToken(Loc: Close);
114 if (Close.isValid()) {
115 S.Diag(Open, diag::note_unreachable_silence)
116 << FixItHint::CreateInsertion(Open, "/* DISABLES CODE */ (")
117 << FixItHint::CreateInsertion(Close, ")");
118 }
119 }
120 }
121 };
122} // anonymous namespace
123
124/// CheckUnreachable - Check for unreachable code.
125static void CheckUnreachable(Sema &S, AnalysisDeclContext &AC) {
126 // As a heuristic prune all diagnostics not in the main file. Currently
127 // the majority of warnings in headers are false positives. These
128 // are largely caused by configuration state, e.g. preprocessor
129 // defined code, etc.
130 //
131 // Note that this is also a performance optimization. Analyzing
132 // headers many times can be expensive.
133 if (!S.getSourceManager().isInMainFile(Loc: AC.getDecl()->getBeginLoc()))
134 return;
135
136 UnreachableCodeHandler UC(S);
137 reachable_code::FindUnreachableCode(AC, PP&: S.getPreprocessor(), CB&: UC);
138}
139
140namespace {
141/// Warn on logical operator errors in CFGBuilder
142class LogicalErrorHandler : public CFGCallback {
143 Sema &S;
144
145public:
146 LogicalErrorHandler(Sema &S) : S(S) {}
147
148 static bool HasMacroID(const Expr *E) {
149 if (E->getExprLoc().isMacroID())
150 return true;
151
152 // Recurse to children.
153 for (const Stmt *SubStmt : E->children())
154 if (const Expr *SubExpr = dyn_cast_or_null<Expr>(SubStmt))
155 if (HasMacroID(SubExpr))
156 return true;
157
158 return false;
159 }
160
161 void logicAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue) override {
162 if (HasMacroID(B))
163 return;
164
165 unsigned DiagID = isAlwaysTrue
166 ? diag::warn_tautological_negation_or_compare
167 : diag::warn_tautological_negation_and_compare;
168 SourceRange DiagRange = B->getSourceRange();
169 S.Diag(Loc: B->getExprLoc(), DiagID) << DiagRange;
170 }
171
172 void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue) override {
173 if (HasMacroID(B))
174 return;
175
176 SourceRange DiagRange = B->getSourceRange();
177 S.Diag(B->getExprLoc(), diag::warn_tautological_overlap_comparison)
178 << DiagRange << isAlwaysTrue;
179 }
180
181 void compareBitwiseEquality(const BinaryOperator *B,
182 bool isAlwaysTrue) override {
183 if (HasMacroID(B))
184 return;
185
186 SourceRange DiagRange = B->getSourceRange();
187 S.Diag(B->getExprLoc(), diag::warn_comparison_bitwise_always)
188 << DiagRange << isAlwaysTrue;
189 }
190
191 void compareBitwiseOr(const BinaryOperator *B) override {
192 if (HasMacroID(B))
193 return;
194
195 SourceRange DiagRange = B->getSourceRange();
196 S.Diag(B->getExprLoc(), diag::warn_comparison_bitwise_or) << DiagRange;
197 }
198
199 static bool hasActiveDiagnostics(DiagnosticsEngine &Diags,
200 SourceLocation Loc) {
201 return !Diags.isIgnored(diag::warn_tautological_overlap_comparison, Loc) ||
202 !Diags.isIgnored(diag::warn_comparison_bitwise_or, Loc) ||
203 !Diags.isIgnored(diag::warn_tautological_negation_and_compare, Loc);
204 }
205};
206} // anonymous namespace
207
208//===----------------------------------------------------------------------===//
209// Check for infinite self-recursion in functions
210//===----------------------------------------------------------------------===//
211
212// Returns true if the function is called anywhere within the CFGBlock.
213// For member functions, the additional condition of being call from the
214// this pointer is required.
215static bool hasRecursiveCallInPath(const FunctionDecl *FD, CFGBlock &Block) {
216 // Process all the Stmt's in this block to find any calls to FD.
217 for (const auto &B : Block) {
218 if (B.getKind() != CFGElement::Statement)
219 continue;
220
221 const CallExpr *CE = dyn_cast<CallExpr>(Val: B.getAs<CFGStmt>()->getStmt());
222 if (!CE || !CE->getCalleeDecl() ||
223 CE->getCalleeDecl()->getCanonicalDecl() != FD)
224 continue;
225
226 // Skip function calls which are qualified with a templated class.
227 if (const DeclRefExpr *DRE =
228 dyn_cast<DeclRefExpr>(Val: CE->getCallee()->IgnoreParenImpCasts())) {
229 if (NestedNameSpecifier *NNS = DRE->getQualifier()) {
230 if (NNS->getKind() == NestedNameSpecifier::TypeSpec &&
231 isa<TemplateSpecializationType>(Val: NNS->getAsType())) {
232 continue;
233 }
234 }
235 }
236
237 const CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(Val: CE);
238 if (!MCE || isa<CXXThisExpr>(Val: MCE->getImplicitObjectArgument()) ||
239 !MCE->getMethodDecl()->isVirtual())
240 return true;
241 }
242 return false;
243}
244
245// Returns true if every path from the entry block passes through a call to FD.
246static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg) {
247 llvm::SmallPtrSet<CFGBlock *, 16> Visited;
248 llvm::SmallVector<CFGBlock *, 16> WorkList;
249 // Keep track of whether we found at least one recursive path.
250 bool foundRecursion = false;
251
252 const unsigned ExitID = cfg->getExit().getBlockID();
253
254 // Seed the work list with the entry block.
255 WorkList.push_back(Elt: &cfg->getEntry());
256
257 while (!WorkList.empty()) {
258 CFGBlock *Block = WorkList.pop_back_val();
259
260 for (auto I = Block->succ_begin(), E = Block->succ_end(); I != E; ++I) {
261 if (CFGBlock *SuccBlock = *I) {
262 if (!Visited.insert(Ptr: SuccBlock).second)
263 continue;
264
265 // Found a path to the exit node without a recursive call.
266 if (ExitID == SuccBlock->getBlockID())
267 return false;
268
269 // If the successor block contains a recursive call, end analysis there.
270 if (hasRecursiveCallInPath(FD, Block&: *SuccBlock)) {
271 foundRecursion = true;
272 continue;
273 }
274
275 WorkList.push_back(Elt: SuccBlock);
276 }
277 }
278 }
279 return foundRecursion;
280}
281
282static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD,
283 const Stmt *Body, AnalysisDeclContext &AC) {
284 FD = FD->getCanonicalDecl();
285
286 // Only run on non-templated functions and non-templated members of
287 // templated classes.
288 if (FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate &&
289 FD->getTemplatedKind() != FunctionDecl::TK_MemberSpecialization)
290 return;
291
292 CFG *cfg = AC.getCFG();
293 if (!cfg) return;
294
295 // If the exit block is unreachable, skip processing the function.
296 if (cfg->getExit().pred_empty())
297 return;
298
299 // Emit diagnostic if a recursive function call is detected for all paths.
300 if (checkForRecursiveFunctionCall(FD, cfg))
301 S.Diag(Body->getBeginLoc(), diag::warn_infinite_recursive_function);
302}
303
304//===----------------------------------------------------------------------===//
305// Check for throw in a non-throwing function.
306//===----------------------------------------------------------------------===//
307
308/// Determine whether an exception thrown by E, unwinding from ThrowBlock,
309/// can reach ExitBlock.
310static bool throwEscapes(Sema &S, const CXXThrowExpr *E, CFGBlock &ThrowBlock,
311 CFG *Body) {
312 SmallVector<CFGBlock *, 16> Stack;
313 llvm::BitVector Queued(Body->getNumBlockIDs());
314
315 Stack.push_back(Elt: &ThrowBlock);
316 Queued[ThrowBlock.getBlockID()] = true;
317
318 while (!Stack.empty()) {
319 CFGBlock &UnwindBlock = *Stack.back();
320 Stack.pop_back();
321
322 for (auto &Succ : UnwindBlock.succs()) {
323 if (!Succ.isReachable() || Queued[Succ->getBlockID()])
324 continue;
325
326 if (Succ->getBlockID() == Body->getExit().getBlockID())
327 return true;
328
329 if (auto *Catch =
330 dyn_cast_or_null<CXXCatchStmt>(Val: Succ->getLabel())) {
331 QualType Caught = Catch->getCaughtType();
332 if (Caught.isNull() || // catch (...) catches everything
333 !E->getSubExpr() || // throw; is considered cuaght by any handler
334 S.handlerCanCatch(HandlerType: Caught, ExceptionType: E->getSubExpr()->getType()))
335 // Exception doesn't escape via this path.
336 break;
337 } else {
338 Stack.push_back(Elt: Succ);
339 Queued[Succ->getBlockID()] = true;
340 }
341 }
342 }
343
344 return false;
345}
346
347static void visitReachableThrows(
348 CFG *BodyCFG,
349 llvm::function_ref<void(const CXXThrowExpr *, CFGBlock &)> Visit) {
350 llvm::BitVector Reachable(BodyCFG->getNumBlockIDs());
351 clang::reachable_code::ScanReachableFromBlock(Start: &BodyCFG->getEntry(), Reachable);
352 for (CFGBlock *B : *BodyCFG) {
353 if (!Reachable[B->getBlockID()])
354 continue;
355 for (CFGElement &E : *B) {
356 std::optional<CFGStmt> S = E.getAs<CFGStmt>();
357 if (!S)
358 continue;
359 if (auto *Throw = dyn_cast<CXXThrowExpr>(Val: S->getStmt()))
360 Visit(Throw, *B);
361 }
362 }
363}
364
365static void EmitDiagForCXXThrowInNonThrowingFunc(Sema &S, SourceLocation OpLoc,
366 const FunctionDecl *FD) {
367 if (!S.getSourceManager().isInSystemHeader(Loc: OpLoc) &&
368 FD->getTypeSourceInfo()) {
369 S.Diag(OpLoc, diag::warn_throw_in_noexcept_func) << FD;
370 if (S.getLangOpts().CPlusPlus11 &&
371 (isa<CXXDestructorDecl>(Val: FD) ||
372 FD->getDeclName().getCXXOverloadedOperator() == OO_Delete ||
373 FD->getDeclName().getCXXOverloadedOperator() == OO_Array_Delete)) {
374 if (const auto *Ty = FD->getTypeSourceInfo()->getType()->
375 getAs<FunctionProtoType>())
376 S.Diag(FD->getLocation(), diag::note_throw_in_dtor)
377 << !isa<CXXDestructorDecl>(FD) << !Ty->hasExceptionSpec()
378 << FD->getExceptionSpecSourceRange();
379 } else
380 S.Diag(FD->getLocation(), diag::note_throw_in_function)
381 << FD->getExceptionSpecSourceRange();
382 }
383}
384
385static void checkThrowInNonThrowingFunc(Sema &S, const FunctionDecl *FD,
386 AnalysisDeclContext &AC) {
387 CFG *BodyCFG = AC.getCFG();
388 if (!BodyCFG)
389 return;
390 if (BodyCFG->getExit().pred_empty())
391 return;
392 visitReachableThrows(BodyCFG, Visit: [&](const CXXThrowExpr *Throw, CFGBlock &Block) {
393 if (throwEscapes(S, E: Throw, ThrowBlock&: Block, Body: BodyCFG))
394 EmitDiagForCXXThrowInNonThrowingFunc(S, OpLoc: Throw->getThrowLoc(), FD);
395 });
396}
397
398static bool isNoexcept(const FunctionDecl *FD) {
399 const auto *FPT = FD->getType()->castAs<FunctionProtoType>();
400 if (FPT->isNothrow() || FD->hasAttr<NoThrowAttr>())
401 return true;
402 return false;
403}
404
405//===----------------------------------------------------------------------===//
406// Check for missing return value.
407//===----------------------------------------------------------------------===//
408
409enum ControlFlowKind {
410 UnknownFallThrough,
411 NeverFallThrough,
412 MaybeFallThrough,
413 AlwaysFallThrough,
414 NeverFallThroughOrReturn
415};
416
417/// CheckFallThrough - Check that we don't fall off the end of a
418/// Statement that should return a value.
419///
420/// \returns AlwaysFallThrough iff we always fall off the end of the statement,
421/// MaybeFallThrough iff we might or might not fall off the end,
422/// NeverFallThroughOrReturn iff we never fall off the end of the statement or
423/// return. We assume NeverFallThrough iff we never fall off the end of the
424/// statement but we may return. We assume that functions not marked noreturn
425/// will return.
426static ControlFlowKind CheckFallThrough(AnalysisDeclContext &AC) {
427 CFG *cfg = AC.getCFG();
428 if (!cfg) return UnknownFallThrough;
429
430 // The CFG leaves in dead things, and we don't want the dead code paths to
431 // confuse us, so we mark all live things first.
432 llvm::BitVector live(cfg->getNumBlockIDs());
433 unsigned count = reachable_code::ScanReachableFromBlock(Start: &cfg->getEntry(),
434 Reachable&: live);
435
436 bool AddEHEdges = AC.getAddEHEdges();
437 if (!AddEHEdges && count != cfg->getNumBlockIDs())
438 // When there are things remaining dead, and we didn't add EH edges
439 // from CallExprs to the catch clauses, we have to go back and
440 // mark them as live.
441 for (const auto *B : *cfg) {
442 if (!live[B->getBlockID()]) {
443 if (B->pred_begin() == B->pred_end()) {
444 const Stmt *Term = B->getTerminatorStmt();
445 if (Term && isa<CXXTryStmt>(Val: Term))
446 // When not adding EH edges from calls, catch clauses
447 // can otherwise seem dead. Avoid noting them as dead.
448 count += reachable_code::ScanReachableFromBlock(Start: B, Reachable&: live);
449 continue;
450 }
451 }
452 }
453
454 // Now we know what is live, we check the live precessors of the exit block
455 // and look for fall through paths, being careful to ignore normal returns,
456 // and exceptional paths.
457 bool HasLiveReturn = false;
458 bool HasFakeEdge = false;
459 bool HasPlainEdge = false;
460 bool HasAbnormalEdge = false;
461
462 // Ignore default cases that aren't likely to be reachable because all
463 // enums in a switch(X) have explicit case statements.
464 CFGBlock::FilterOptions FO;
465 FO.IgnoreDefaultsWithCoveredEnums = 1;
466
467 for (CFGBlock::filtered_pred_iterator I =
468 cfg->getExit().filtered_pred_start_end(f: FO);
469 I.hasMore(); ++I) {
470 const CFGBlock &B = **I;
471 if (!live[B.getBlockID()])
472 continue;
473
474 // Skip blocks which contain an element marked as no-return. They don't
475 // represent actually viable edges into the exit block, so mark them as
476 // abnormal.
477 if (B.hasNoReturnElement()) {
478 HasAbnormalEdge = true;
479 continue;
480 }
481
482 // Destructors can appear after the 'return' in the CFG. This is
483 // normal. We need to look pass the destructors for the return
484 // statement (if it exists).
485 CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
486
487 for ( ; ri != re ; ++ri)
488 if (ri->getAs<CFGStmt>())
489 break;
490
491 // No more CFGElements in the block?
492 if (ri == re) {
493 const Stmt *Term = B.getTerminatorStmt();
494 if (Term && (isa<CXXTryStmt>(Val: Term) || isa<ObjCAtTryStmt>(Val: Term))) {
495 HasAbnormalEdge = true;
496 continue;
497 }
498 // A labeled empty statement, or the entry block...
499 HasPlainEdge = true;
500 continue;
501 }
502
503 CFGStmt CS = ri->castAs<CFGStmt>();
504 const Stmt *S = CS.getStmt();
505 if (isa<ReturnStmt>(Val: S) || isa<CoreturnStmt>(Val: S)) {
506 HasLiveReturn = true;
507 continue;
508 }
509 if (isa<ObjCAtThrowStmt>(Val: S)) {
510 HasFakeEdge = true;
511 continue;
512 }
513 if (isa<CXXThrowExpr>(Val: S)) {
514 HasFakeEdge = true;
515 continue;
516 }
517 if (isa<MSAsmStmt>(Val: S)) {
518 // TODO: Verify this is correct.
519 HasFakeEdge = true;
520 HasLiveReturn = true;
521 continue;
522 }
523 if (isa<CXXTryStmt>(Val: S)) {
524 HasAbnormalEdge = true;
525 continue;
526 }
527 if (!llvm::is_contained(Range: B.succs(), Element: &cfg->getExit())) {
528 HasAbnormalEdge = true;
529 continue;
530 }
531
532 HasPlainEdge = true;
533 }
534 if (!HasPlainEdge) {
535 if (HasLiveReturn)
536 return NeverFallThrough;
537 return NeverFallThroughOrReturn;
538 }
539 if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
540 return MaybeFallThrough;
541 // This says AlwaysFallThrough for calls to functions that are not marked
542 // noreturn, that don't return. If people would like this warning to be more
543 // accurate, such functions should be marked as noreturn.
544 return AlwaysFallThrough;
545}
546
547namespace {
548
549struct CheckFallThroughDiagnostics {
550 unsigned diag_MaybeFallThrough_HasNoReturn;
551 unsigned diag_MaybeFallThrough_ReturnsNonVoid;
552 unsigned diag_AlwaysFallThrough_HasNoReturn;
553 unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
554 unsigned diag_NeverFallThroughOrReturn;
555 enum { Function, Block, Lambda, Coroutine } funMode;
556 SourceLocation FuncLoc;
557
558 static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
559 CheckFallThroughDiagnostics D;
560 D.FuncLoc = Func->getLocation();
561 D.diag_MaybeFallThrough_HasNoReturn =
562 diag::warn_falloff_noreturn_function;
563 D.diag_MaybeFallThrough_ReturnsNonVoid =
564 diag::warn_maybe_falloff_nonvoid_function;
565 D.diag_AlwaysFallThrough_HasNoReturn =
566 diag::warn_falloff_noreturn_function;
567 D.diag_AlwaysFallThrough_ReturnsNonVoid =
568 diag::warn_falloff_nonvoid_function;
569
570 // Don't suggest that virtual functions be marked "noreturn", since they
571 // might be overridden by non-noreturn functions.
572 bool isVirtualMethod = false;
573 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Val: Func))
574 isVirtualMethod = Method->isVirtual();
575
576 // Don't suggest that template instantiations be marked "noreturn"
577 bool isTemplateInstantiation = false;
578 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Val: Func))
579 isTemplateInstantiation = Function->isTemplateInstantiation();
580
581 if (!isVirtualMethod && !isTemplateInstantiation)
582 D.diag_NeverFallThroughOrReturn =
583 diag::warn_suggest_noreturn_function;
584 else
585 D.diag_NeverFallThroughOrReturn = 0;
586
587 D.funMode = Function;
588 return D;
589 }
590
591 static CheckFallThroughDiagnostics MakeForCoroutine(const Decl *Func) {
592 CheckFallThroughDiagnostics D;
593 D.FuncLoc = Func->getLocation();
594 D.diag_MaybeFallThrough_HasNoReturn = 0;
595 D.diag_MaybeFallThrough_ReturnsNonVoid =
596 diag::warn_maybe_falloff_nonvoid_coroutine;
597 D.diag_AlwaysFallThrough_HasNoReturn = 0;
598 D.diag_AlwaysFallThrough_ReturnsNonVoid =
599 diag::warn_falloff_nonvoid_coroutine;
600 D.diag_NeverFallThroughOrReturn = 0;
601 D.funMode = Coroutine;
602 return D;
603 }
604
605 static CheckFallThroughDiagnostics MakeForBlock() {
606 CheckFallThroughDiagnostics D;
607 D.diag_MaybeFallThrough_HasNoReturn =
608 diag::err_noreturn_block_has_return_expr;
609 D.diag_MaybeFallThrough_ReturnsNonVoid =
610 diag::err_maybe_falloff_nonvoid_block;
611 D.diag_AlwaysFallThrough_HasNoReturn =
612 diag::err_noreturn_block_has_return_expr;
613 D.diag_AlwaysFallThrough_ReturnsNonVoid =
614 diag::err_falloff_nonvoid_block;
615 D.diag_NeverFallThroughOrReturn = 0;
616 D.funMode = Block;
617 return D;
618 }
619
620 static CheckFallThroughDiagnostics MakeForLambda() {
621 CheckFallThroughDiagnostics D;
622 D.diag_MaybeFallThrough_HasNoReturn =
623 diag::err_noreturn_lambda_has_return_expr;
624 D.diag_MaybeFallThrough_ReturnsNonVoid =
625 diag::warn_maybe_falloff_nonvoid_lambda;
626 D.diag_AlwaysFallThrough_HasNoReturn =
627 diag::err_noreturn_lambda_has_return_expr;
628 D.diag_AlwaysFallThrough_ReturnsNonVoid =
629 diag::warn_falloff_nonvoid_lambda;
630 D.diag_NeverFallThroughOrReturn = 0;
631 D.funMode = Lambda;
632 return D;
633 }
634
635 bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
636 bool HasNoReturn) const {
637 if (funMode == Function) {
638 return (ReturnsVoid ||
639 D.isIgnored(diag::warn_maybe_falloff_nonvoid_function,
640 FuncLoc)) &&
641 (!HasNoReturn ||
642 D.isIgnored(diag::warn_noreturn_function_has_return_expr,
643 FuncLoc)) &&
644 (!ReturnsVoid ||
645 D.isIgnored(diag::warn_suggest_noreturn_block, FuncLoc));
646 }
647 if (funMode == Coroutine) {
648 return (ReturnsVoid ||
649 D.isIgnored(diag::warn_maybe_falloff_nonvoid_function, FuncLoc) ||
650 D.isIgnored(diag::warn_maybe_falloff_nonvoid_coroutine,
651 FuncLoc)) &&
652 (!HasNoReturn);
653 }
654 // For blocks / lambdas.
655 return ReturnsVoid && !HasNoReturn;
656 }
657};
658
659} // anonymous namespace
660
661/// CheckFallThroughForBody - Check that we don't fall off the end of a
662/// function that should return a value. Check that we don't fall off the end
663/// of a noreturn function. We assume that functions and blocks not marked
664/// noreturn will return.
665static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
666 QualType BlockType,
667 const CheckFallThroughDiagnostics &CD,
668 AnalysisDeclContext &AC,
669 sema::FunctionScopeInfo *FSI) {
670
671 bool ReturnsVoid = false;
672 bool HasNoReturn = false;
673 bool IsCoroutine = FSI->isCoroutine();
674
675 if (const auto *FD = dyn_cast<FunctionDecl>(Val: D)) {
676 if (const auto *CBody = dyn_cast<CoroutineBodyStmt>(Val: Body))
677 ReturnsVoid = CBody->getFallthroughHandler() != nullptr;
678 else
679 ReturnsVoid = FD->getReturnType()->isVoidType();
680 HasNoReturn = FD->isNoReturn();
681 }
682 else if (const auto *MD = dyn_cast<ObjCMethodDecl>(Val: D)) {
683 ReturnsVoid = MD->getReturnType()->isVoidType();
684 HasNoReturn = MD->hasAttr<NoReturnAttr>();
685 }
686 else if (isa<BlockDecl>(Val: D)) {
687 if (const FunctionType *FT =
688 BlockType->getPointeeType()->getAs<FunctionType>()) {
689 if (FT->getReturnType()->isVoidType())
690 ReturnsVoid = true;
691 if (FT->getNoReturnAttr())
692 HasNoReturn = true;
693 }
694 }
695
696 DiagnosticsEngine &Diags = S.getDiagnostics();
697
698 // Short circuit for compilation speed.
699 if (CD.checkDiagnostics(D&: Diags, ReturnsVoid, HasNoReturn))
700 return;
701 SourceLocation LBrace = Body->getBeginLoc(), RBrace = Body->getEndLoc();
702 auto EmitDiag = [&](SourceLocation Loc, unsigned DiagID) {
703 if (IsCoroutine)
704 S.Diag(Loc, DiagID) << FSI->CoroutinePromise->getType();
705 else
706 S.Diag(Loc, DiagID);
707 };
708
709 // cpu_dispatch functions permit empty function bodies for ICC compatibility.
710 if (D->getAsFunction() && D->getAsFunction()->isCPUDispatchMultiVersion())
711 return;
712
713 // Either in a function body compound statement, or a function-try-block.
714 switch (CheckFallThrough(AC)) {
715 case UnknownFallThrough:
716 break;
717
718 case MaybeFallThrough:
719 if (HasNoReturn)
720 EmitDiag(RBrace, CD.diag_MaybeFallThrough_HasNoReturn);
721 else if (!ReturnsVoid)
722 EmitDiag(RBrace, CD.diag_MaybeFallThrough_ReturnsNonVoid);
723 break;
724 case AlwaysFallThrough:
725 if (HasNoReturn)
726 EmitDiag(RBrace, CD.diag_AlwaysFallThrough_HasNoReturn);
727 else if (!ReturnsVoid)
728 EmitDiag(RBrace, CD.diag_AlwaysFallThrough_ReturnsNonVoid);
729 break;
730 case NeverFallThroughOrReturn:
731 if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
732 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Val: D)) {
733 S.Diag(Loc: LBrace, DiagID: CD.diag_NeverFallThroughOrReturn) << 0 << FD;
734 } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(Val: D)) {
735 S.Diag(Loc: LBrace, DiagID: CD.diag_NeverFallThroughOrReturn) << 1 << MD;
736 } else {
737 S.Diag(Loc: LBrace, DiagID: CD.diag_NeverFallThroughOrReturn);
738 }
739 }
740 break;
741 case NeverFallThrough:
742 break;
743 }
744}
745
746//===----------------------------------------------------------------------===//
747// -Wuninitialized
748//===----------------------------------------------------------------------===//
749
750namespace {
751/// ContainsReference - A visitor class to search for references to
752/// a particular declaration (the needle) within any evaluated component of an
753/// expression (recursively).
754class ContainsReference : public ConstEvaluatedExprVisitor<ContainsReference> {
755 bool FoundReference;
756 const DeclRefExpr *Needle;
757
758public:
759 typedef ConstEvaluatedExprVisitor<ContainsReference> Inherited;
760
761 ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
762 : Inherited(Context), FoundReference(false), Needle(Needle) {}
763
764 void VisitExpr(const Expr *E) {
765 // Stop evaluating if we already have a reference.
766 if (FoundReference)
767 return;
768
769 Inherited::VisitExpr(E);
770 }
771
772 void VisitDeclRefExpr(const DeclRefExpr *E) {
773 if (E == Needle)
774 FoundReference = true;
775 else
776 Inherited::VisitDeclRefExpr(E);
777 }
778
779 bool doesContainReference() const { return FoundReference; }
780};
781} // anonymous namespace
782
783static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
784 QualType VariableTy = VD->getType().getCanonicalType();
785 if (VariableTy->isBlockPointerType() &&
786 !VD->hasAttr<BlocksAttr>()) {
787 S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization)
788 << VD->getDeclName()
789 << FixItHint::CreateInsertion(VD->getLocation(), "__block ");
790 return true;
791 }
792
793 // Don't issue a fixit if there is already an initializer.
794 if (VD->getInit())
795 return false;
796
797 // Don't suggest a fixit inside macros.
798 if (VD->getEndLoc().isMacroID())
799 return false;
800
801 SourceLocation Loc = S.getLocForEndOfToken(Loc: VD->getEndLoc());
802
803 // Suggest possible initialization (if any).
804 std::string Init = S.getFixItZeroInitializerForType(T: VariableTy, Loc);
805 if (Init.empty())
806 return false;
807
808 S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
809 << FixItHint::CreateInsertion(Loc, Init);
810 return true;
811}
812
813/// Create a fixit to remove an if-like statement, on the assumption that its
814/// condition is CondVal.
815static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then,
816 const Stmt *Else, bool CondVal,
817 FixItHint &Fixit1, FixItHint &Fixit2) {
818 if (CondVal) {
819 // If condition is always true, remove all but the 'then'.
820 Fixit1 = FixItHint::CreateRemoval(
821 RemoveRange: CharSourceRange::getCharRange(B: If->getBeginLoc(), E: Then->getBeginLoc()));
822 if (Else) {
823 SourceLocation ElseKwLoc = S.getLocForEndOfToken(Loc: Then->getEndLoc());
824 Fixit2 =
825 FixItHint::CreateRemoval(RemoveRange: SourceRange(ElseKwLoc, Else->getEndLoc()));
826 }
827 } else {
828 // If condition is always false, remove all but the 'else'.
829 if (Else)
830 Fixit1 = FixItHint::CreateRemoval(RemoveRange: CharSourceRange::getCharRange(
831 B: If->getBeginLoc(), E: Else->getBeginLoc()));
832 else
833 Fixit1 = FixItHint::CreateRemoval(RemoveRange: If->getSourceRange());
834 }
835}
836
837/// DiagUninitUse -- Helper function to produce a diagnostic for an
838/// uninitialized use of a variable.
839static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
840 bool IsCapturedByBlock) {
841 bool Diagnosed = false;
842
843 switch (Use.getKind()) {
844 case UninitUse::Always:
845 S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_var)
846 << VD->getDeclName() << IsCapturedByBlock
847 << Use.getUser()->getSourceRange();
848 return;
849
850 case UninitUse::AfterDecl:
851 case UninitUse::AfterCall:
852 S.Diag(VD->getLocation(), diag::warn_sometimes_uninit_var)
853 << VD->getDeclName() << IsCapturedByBlock
854 << (Use.getKind() == UninitUse::AfterDecl ? 4 : 5)
855 << const_cast<DeclContext*>(VD->getLexicalDeclContext())
856 << VD->getSourceRange();
857 S.Diag(Use.getUser()->getBeginLoc(), diag::note_uninit_var_use)
858 << IsCapturedByBlock << Use.getUser()->getSourceRange();
859 return;
860
861 case UninitUse::Maybe:
862 case UninitUse::Sometimes:
863 // Carry on to report sometimes-uninitialized branches, if possible,
864 // or a 'may be used uninitialized' diagnostic otherwise.
865 break;
866 }
867
868 // Diagnose each branch which leads to a sometimes-uninitialized use.
869 for (UninitUse::branch_iterator I = Use.branch_begin(), E = Use.branch_end();
870 I != E; ++I) {
871 assert(Use.getKind() == UninitUse::Sometimes);
872
873 const Expr *User = Use.getUser();
874 const Stmt *Term = I->Terminator;
875
876 // Information used when building the diagnostic.
877 unsigned DiagKind;
878 StringRef Str;
879 SourceRange Range;
880
881 // FixIts to suppress the diagnostic by removing the dead condition.
882 // For all binary terminators, branch 0 is taken if the condition is true,
883 // and branch 1 is taken if the condition is false.
884 int RemoveDiagKind = -1;
885 const char *FixitStr =
886 S.getLangOpts().CPlusPlus ? (I->Output ? "true" : "false")
887 : (I->Output ? "1" : "0");
888 FixItHint Fixit1, Fixit2;
889
890 switch (Term ? Term->getStmtClass() : Stmt::DeclStmtClass) {
891 default:
892 // Don't know how to report this. Just fall back to 'may be used
893 // uninitialized'. FIXME: Can this happen?
894 continue;
895
896 // "condition is true / condition is false".
897 case Stmt::IfStmtClass: {
898 const IfStmt *IS = cast<IfStmt>(Val: Term);
899 DiagKind = 0;
900 Str = "if";
901 Range = IS->getCond()->getSourceRange();
902 RemoveDiagKind = 0;
903 CreateIfFixit(S, IS, IS->getThen(), IS->getElse(),
904 I->Output, Fixit1, Fixit2);
905 break;
906 }
907 case Stmt::ConditionalOperatorClass: {
908 const ConditionalOperator *CO = cast<ConditionalOperator>(Val: Term);
909 DiagKind = 0;
910 Str = "?:";
911 Range = CO->getCond()->getSourceRange();
912 RemoveDiagKind = 0;
913 CreateIfFixit(S, CO, CO->getTrueExpr(), CO->getFalseExpr(),
914 I->Output, Fixit1, Fixit2);
915 break;
916 }
917 case Stmt::BinaryOperatorClass: {
918 const BinaryOperator *BO = cast<BinaryOperator>(Val: Term);
919 if (!BO->isLogicalOp())
920 continue;
921 DiagKind = 0;
922 Str = BO->getOpcodeStr();
923 Range = BO->getLHS()->getSourceRange();
924 RemoveDiagKind = 0;
925 if ((BO->getOpcode() == BO_LAnd && I->Output) ||
926 (BO->getOpcode() == BO_LOr && !I->Output))
927 // true && y -> y, false || y -> y.
928 Fixit1 = FixItHint::CreateRemoval(
929 RemoveRange: SourceRange(BO->getBeginLoc(), BO->getOperatorLoc()));
930 else
931 // false && y -> false, true || y -> true.
932 Fixit1 = FixItHint::CreateReplacement(BO->getSourceRange(), FixitStr);
933 break;
934 }
935
936 // "loop is entered / loop is exited".
937 case Stmt::WhileStmtClass:
938 DiagKind = 1;
939 Str = "while";
940 Range = cast<WhileStmt>(Val: Term)->getCond()->getSourceRange();
941 RemoveDiagKind = 1;
942 Fixit1 = FixItHint::CreateReplacement(RemoveRange: Range, Code: FixitStr);
943 break;
944 case Stmt::ForStmtClass:
945 DiagKind = 1;
946 Str = "for";
947 Range = cast<ForStmt>(Val: Term)->getCond()->getSourceRange();
948 RemoveDiagKind = 1;
949 if (I->Output)
950 Fixit1 = FixItHint::CreateRemoval(RemoveRange: Range);
951 else
952 Fixit1 = FixItHint::CreateReplacement(RemoveRange: Range, Code: FixitStr);
953 break;
954 case Stmt::CXXForRangeStmtClass:
955 if (I->Output == 1) {
956 // The use occurs if a range-based for loop's body never executes.
957 // That may be impossible, and there's no syntactic fix for this,
958 // so treat it as a 'may be uninitialized' case.
959 continue;
960 }
961 DiagKind = 1;
962 Str = "for";
963 Range = cast<CXXForRangeStmt>(Val: Term)->getRangeInit()->getSourceRange();
964 break;
965
966 // "condition is true / loop is exited".
967 case Stmt::DoStmtClass:
968 DiagKind = 2;
969 Str = "do";
970 Range = cast<DoStmt>(Val: Term)->getCond()->getSourceRange();
971 RemoveDiagKind = 1;
972 Fixit1 = FixItHint::CreateReplacement(RemoveRange: Range, Code: FixitStr);
973 break;
974
975 // "switch case is taken".
976 case Stmt::CaseStmtClass:
977 DiagKind = 3;
978 Str = "case";
979 Range = cast<CaseStmt>(Val: Term)->getLHS()->getSourceRange();
980 break;
981 case Stmt::DefaultStmtClass:
982 DiagKind = 3;
983 Str = "default";
984 Range = cast<DefaultStmt>(Val: Term)->getDefaultLoc();
985 break;
986 }
987
988 S.Diag(Range.getBegin(), diag::warn_sometimes_uninit_var)
989 << VD->getDeclName() << IsCapturedByBlock << DiagKind
990 << Str << I->Output << Range;
991 S.Diag(User->getBeginLoc(), diag::note_uninit_var_use)
992 << IsCapturedByBlock << User->getSourceRange();
993 if (RemoveDiagKind != -1)
994 S.Diag(Fixit1.RemoveRange.getBegin(), diag::note_uninit_fixit_remove_cond)
995 << RemoveDiagKind << Str << I->Output << Fixit1 << Fixit2;
996
997 Diagnosed = true;
998 }
999
1000 if (!Diagnosed)
1001 S.Diag(Use.getUser()->getBeginLoc(), diag::warn_maybe_uninit_var)
1002 << VD->getDeclName() << IsCapturedByBlock
1003 << Use.getUser()->getSourceRange();
1004}
1005
1006/// Diagnose uninitialized const reference usages.
1007static bool DiagnoseUninitializedConstRefUse(Sema &S, const VarDecl *VD,
1008 const UninitUse &Use) {
1009 S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_const_reference)
1010 << VD->getDeclName() << Use.getUser()->getSourceRange();
1011 return true;
1012}
1013
1014/// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
1015/// uninitialized variable. This manages the different forms of diagnostic
1016/// emitted for particular types of uses. Returns true if the use was diagnosed
1017/// as a warning. If a particular use is one we omit warnings for, returns
1018/// false.
1019static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
1020 const UninitUse &Use,
1021 bool alwaysReportSelfInit = false) {
1022 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: Use.getUser())) {
1023 // Inspect the initializer of the variable declaration which is
1024 // being referenced prior to its initialization. We emit
1025 // specialized diagnostics for self-initialization, and we
1026 // specifically avoid warning about self references which take the
1027 // form of:
1028 //
1029 // int x = x;
1030 //
1031 // This is used to indicate to GCC that 'x' is intentionally left
1032 // uninitialized. Proven code paths which access 'x' in
1033 // an uninitialized state after this will still warn.
1034 if (const Expr *Initializer = VD->getInit()) {
1035 if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
1036 return false;
1037
1038 ContainsReference CR(S.Context, DRE);
1039 CR.Visit(Initializer);
1040 if (CR.doesContainReference()) {
1041 S.Diag(DRE->getBeginLoc(), diag::warn_uninit_self_reference_in_init)
1042 << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
1043 return true;
1044 }
1045 }
1046
1047 DiagUninitUse(S, VD, Use, IsCapturedByBlock: false);
1048 } else {
1049 const BlockExpr *BE = cast<BlockExpr>(Val: Use.getUser());
1050 if (VD->getType()->isBlockPointerType() && !VD->hasAttr<BlocksAttr>())
1051 S.Diag(BE->getBeginLoc(),
1052 diag::warn_uninit_byref_blockvar_captured_by_block)
1053 << VD->getDeclName()
1054 << VD->getType().getQualifiers().hasObjCLifetime();
1055 else
1056 DiagUninitUse(S, VD, Use, IsCapturedByBlock: true);
1057 }
1058
1059 // Report where the variable was declared when the use wasn't within
1060 // the initializer of that declaration & we didn't already suggest
1061 // an initialization fixit.
1062 if (!SuggestInitializationFixit(S, VD))
1063 S.Diag(VD->getBeginLoc(), diag::note_var_declared_here)
1064 << VD->getDeclName();
1065
1066 return true;
1067}
1068
1069namespace {
1070 class FallthroughMapper : public RecursiveASTVisitor<FallthroughMapper> {
1071 public:
1072 FallthroughMapper(Sema &S)
1073 : FoundSwitchStatements(false),
1074 S(S) {
1075 }
1076
1077 bool foundSwitchStatements() const { return FoundSwitchStatements; }
1078
1079 void markFallthroughVisited(const AttributedStmt *Stmt) {
1080 bool Found = FallthroughStmts.erase(Ptr: Stmt);
1081 assert(Found);
1082 (void)Found;
1083 }
1084
1085 typedef llvm::SmallPtrSet<const AttributedStmt*, 8> AttrStmts;
1086
1087 const AttrStmts &getFallthroughStmts() const {
1088 return FallthroughStmts;
1089 }
1090
1091 void fillReachableBlocks(CFG *Cfg) {
1092 assert(ReachableBlocks.empty() && "ReachableBlocks already filled");
1093 std::deque<const CFGBlock *> BlockQueue;
1094
1095 ReachableBlocks.insert(Ptr: &Cfg->getEntry());
1096 BlockQueue.push_back(x: &Cfg->getEntry());
1097 // Mark all case blocks reachable to avoid problems with switching on
1098 // constants, covered enums, etc.
1099 // These blocks can contain fall-through annotations, and we don't want to
1100 // issue a warn_fallthrough_attr_unreachable for them.
1101 for (const auto *B : *Cfg) {
1102 const Stmt *L = B->getLabel();
1103 if (L && isa<SwitchCase>(Val: L) && ReachableBlocks.insert(Ptr: B).second)
1104 BlockQueue.push_back(x: B);
1105 }
1106
1107 while (!BlockQueue.empty()) {
1108 const CFGBlock *P = BlockQueue.front();
1109 BlockQueue.pop_front();
1110 for (const CFGBlock *B : P->succs()) {
1111 if (B && ReachableBlocks.insert(Ptr: B).second)
1112 BlockQueue.push_back(x: B);
1113 }
1114 }
1115 }
1116
1117 bool checkFallThroughIntoBlock(const CFGBlock &B, int &AnnotatedCnt,
1118 bool IsTemplateInstantiation) {
1119 assert(!ReachableBlocks.empty() && "ReachableBlocks empty");
1120
1121 int UnannotatedCnt = 0;
1122 AnnotatedCnt = 0;
1123
1124 std::deque<const CFGBlock*> BlockQueue(B.pred_begin(), B.pred_end());
1125 while (!BlockQueue.empty()) {
1126 const CFGBlock *P = BlockQueue.front();
1127 BlockQueue.pop_front();
1128 if (!P) continue;
1129
1130 const Stmt *Term = P->getTerminatorStmt();
1131 if (Term && isa<SwitchStmt>(Val: Term))
1132 continue; // Switch statement, good.
1133
1134 const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(Val: P->getLabel());
1135 if (SW && SW->getSubStmt() == B.getLabel() && P->begin() == P->end())
1136 continue; // Previous case label has no statements, good.
1137
1138 const LabelStmt *L = dyn_cast_or_null<LabelStmt>(Val: P->getLabel());
1139 if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end())
1140 continue; // Case label is preceded with a normal label, good.
1141
1142 if (!ReachableBlocks.count(Ptr: P)) {
1143 for (const CFGElement &Elem : llvm::reverse(C: *P)) {
1144 if (std::optional<CFGStmt> CS = Elem.getAs<CFGStmt>()) {
1145 if (const AttributedStmt *AS = asFallThroughAttr(S: CS->getStmt())) {
1146 // Don't issue a warning for an unreachable fallthrough
1147 // attribute in template instantiations as it may not be
1148 // unreachable in all instantiations of the template.
1149 if (!IsTemplateInstantiation)
1150 S.Diag(AS->getBeginLoc(),
1151 diag::warn_unreachable_fallthrough_attr);
1152 markFallthroughVisited(Stmt: AS);
1153 ++AnnotatedCnt;
1154 break;
1155 }
1156 // Don't care about other unreachable statements.
1157 }
1158 }
1159 // If there are no unreachable statements, this may be a special
1160 // case in CFG:
1161 // case X: {
1162 // A a; // A has a destructor.
1163 // break;
1164 // }
1165 // // <<<< This place is represented by a 'hanging' CFG block.
1166 // case Y:
1167 continue;
1168 }
1169
1170 const Stmt *LastStmt = getLastStmt(B: *P);
1171 if (const AttributedStmt *AS = asFallThroughAttr(S: LastStmt)) {
1172 markFallthroughVisited(Stmt: AS);
1173 ++AnnotatedCnt;
1174 continue; // Fallthrough annotation, good.
1175 }
1176
1177 if (!LastStmt) { // This block contains no executable statements.
1178 // Traverse its predecessors.
1179 std::copy(first: P->pred_begin(), last: P->pred_end(),
1180 result: std::back_inserter(x&: BlockQueue));
1181 continue;
1182 }
1183
1184 ++UnannotatedCnt;
1185 }
1186 return !!UnannotatedCnt;
1187 }
1188
1189 // RecursiveASTVisitor setup.
1190 bool shouldWalkTypesOfTypeLocs() const { return false; }
1191
1192 bool VisitAttributedStmt(AttributedStmt *S) {
1193 if (asFallThroughAttr(S))
1194 FallthroughStmts.insert(Ptr: S);
1195 return true;
1196 }
1197
1198 bool VisitSwitchStmt(SwitchStmt *S) {
1199 FoundSwitchStatements = true;
1200 return true;
1201 }
1202
1203 // We don't want to traverse local type declarations. We analyze their
1204 // methods separately.
1205 bool TraverseDecl(Decl *D) { return true; }
1206
1207 // We analyze lambda bodies separately. Skip them here.
1208 bool TraverseLambdaExpr(LambdaExpr *LE) {
1209 // Traverse the captures, but not the body.
1210 for (const auto C : zip(t: LE->captures(), u: LE->capture_inits()))
1211 TraverseLambdaCapture(LE, C: &std::get<0>(t: C), Init: std::get<1>(t: C));
1212 return true;
1213 }
1214
1215 private:
1216
1217 static const AttributedStmt *asFallThroughAttr(const Stmt *S) {
1218 if (const AttributedStmt *AS = dyn_cast_or_null<AttributedStmt>(Val: S)) {
1219 if (hasSpecificAttr<FallThroughAttr>(AS->getAttrs()))
1220 return AS;
1221 }
1222 return nullptr;
1223 }
1224
1225 static const Stmt *getLastStmt(const CFGBlock &B) {
1226 if (const Stmt *Term = B.getTerminatorStmt())
1227 return Term;
1228 for (const CFGElement &Elem : llvm::reverse(C: B))
1229 if (std::optional<CFGStmt> CS = Elem.getAs<CFGStmt>())
1230 return CS->getStmt();
1231 // Workaround to detect a statement thrown out by CFGBuilder:
1232 // case X: {} case Y:
1233 // case X: ; case Y:
1234 if (const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(Val: B.getLabel()))
1235 if (!isa<SwitchCase>(Val: SW->getSubStmt()))
1236 return SW->getSubStmt();
1237
1238 return nullptr;
1239 }
1240
1241 bool FoundSwitchStatements;
1242 AttrStmts FallthroughStmts;
1243 Sema &S;
1244 llvm::SmallPtrSet<const CFGBlock *, 16> ReachableBlocks;
1245 };
1246} // anonymous namespace
1247
1248static StringRef getFallthroughAttrSpelling(Preprocessor &PP,
1249 SourceLocation Loc) {
1250 TokenValue FallthroughTokens[] = {
1251 tok::l_square, tok::l_square,
1252 PP.getIdentifierInfo(Name: "fallthrough"),
1253 tok::r_square, tok::r_square
1254 };
1255
1256 TokenValue ClangFallthroughTokens[] = {
1257 tok::l_square, tok::l_square, PP.getIdentifierInfo(Name: "clang"),
1258 tok::coloncolon, PP.getIdentifierInfo(Name: "fallthrough"),
1259 tok::r_square, tok::r_square
1260 };
1261
1262 bool PreferClangAttr = !PP.getLangOpts().CPlusPlus17 && !PP.getLangOpts().C23;
1263
1264 StringRef MacroName;
1265 if (PreferClangAttr)
1266 MacroName = PP.getLastMacroWithSpelling(Loc, Tokens: ClangFallthroughTokens);
1267 if (MacroName.empty())
1268 MacroName = PP.getLastMacroWithSpelling(Loc, Tokens: FallthroughTokens);
1269 if (MacroName.empty() && !PreferClangAttr)
1270 MacroName = PP.getLastMacroWithSpelling(Loc, Tokens: ClangFallthroughTokens);
1271 if (MacroName.empty()) {
1272 if (!PreferClangAttr)
1273 MacroName = "[[fallthrough]]";
1274 else if (PP.getLangOpts().CPlusPlus)
1275 MacroName = "[[clang::fallthrough]]";
1276 else
1277 MacroName = "__attribute__((fallthrough))";
1278 }
1279 return MacroName;
1280}
1281
1282static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
1283 bool PerFunction) {
1284 FallthroughMapper FM(S);
1285 FM.TraverseStmt(S: AC.getBody());
1286
1287 if (!FM.foundSwitchStatements())
1288 return;
1289
1290 if (PerFunction && FM.getFallthroughStmts().empty())
1291 return;
1292
1293 CFG *Cfg = AC.getCFG();
1294
1295 if (!Cfg)
1296 return;
1297
1298 FM.fillReachableBlocks(Cfg);
1299
1300 for (const CFGBlock *B : llvm::reverse(C&: *Cfg)) {
1301 const Stmt *Label = B->getLabel();
1302
1303 if (!isa_and_nonnull<SwitchCase>(Val: Label))
1304 continue;
1305
1306 int AnnotatedCnt;
1307
1308 bool IsTemplateInstantiation = false;
1309 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Val: AC.getDecl()))
1310 IsTemplateInstantiation = Function->isTemplateInstantiation();
1311 if (!FM.checkFallThroughIntoBlock(B: *B, AnnotatedCnt,
1312 IsTemplateInstantiation))
1313 continue;
1314
1315 S.Diag(Label->getBeginLoc(),
1316 PerFunction ? diag::warn_unannotated_fallthrough_per_function
1317 : diag::warn_unannotated_fallthrough);
1318
1319 if (!AnnotatedCnt) {
1320 SourceLocation L = Label->getBeginLoc();
1321 if (L.isMacroID())
1322 continue;
1323
1324 const Stmt *Term = B->getTerminatorStmt();
1325 // Skip empty cases.
1326 while (B->empty() && !Term && B->succ_size() == 1) {
1327 B = *B->succ_begin();
1328 Term = B->getTerminatorStmt();
1329 }
1330 if (!(B->empty() && Term && isa<BreakStmt>(Val: Term))) {
1331 Preprocessor &PP = S.getPreprocessor();
1332 StringRef AnnotationSpelling = getFallthroughAttrSpelling(PP, Loc: L);
1333 SmallString<64> TextToInsert(AnnotationSpelling);
1334 TextToInsert += "; ";
1335 S.Diag(L, diag::note_insert_fallthrough_fixit)
1336 << AnnotationSpelling
1337 << FixItHint::CreateInsertion(L, TextToInsert);
1338 }
1339 S.Diag(L, diag::note_insert_break_fixit)
1340 << FixItHint::CreateInsertion(L, "break; ");
1341 }
1342 }
1343
1344 for (const auto *F : FM.getFallthroughStmts())
1345 S.Diag(F->getBeginLoc(), diag::err_fallthrough_attr_invalid_placement);
1346}
1347
1348static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
1349 const Stmt *S) {
1350 assert(S);
1351
1352 do {
1353 switch (S->getStmtClass()) {
1354 case Stmt::ForStmtClass:
1355 case Stmt::WhileStmtClass:
1356 case Stmt::CXXForRangeStmtClass:
1357 case Stmt::ObjCForCollectionStmtClass:
1358 return true;
1359 case Stmt::DoStmtClass: {
1360 Expr::EvalResult Result;
1361 if (!cast<DoStmt>(Val: S)->getCond()->EvaluateAsInt(Result, Ctx))
1362 return true;
1363 return Result.Val.getInt().getBoolValue();
1364 }
1365 default:
1366 break;
1367 }
1368 } while ((S = PM.getParent(S)));
1369
1370 return false;
1371}
1372
1373static void diagnoseRepeatedUseOfWeak(Sema &S,
1374 const sema::FunctionScopeInfo *CurFn,
1375 const Decl *D,
1376 const ParentMap &PM) {
1377 typedef sema::FunctionScopeInfo::WeakObjectProfileTy WeakObjectProfileTy;
1378 typedef sema::FunctionScopeInfo::WeakObjectUseMap WeakObjectUseMap;
1379 typedef sema::FunctionScopeInfo::WeakUseVector WeakUseVector;
1380 typedef std::pair<const Stmt *, WeakObjectUseMap::const_iterator>
1381 StmtUsesPair;
1382
1383 ASTContext &Ctx = S.getASTContext();
1384
1385 const WeakObjectUseMap &WeakMap = CurFn->getWeakObjectUses();
1386
1387 // Extract all weak objects that are referenced more than once.
1388 SmallVector<StmtUsesPair, 8> UsesByStmt;
1389 for (WeakObjectUseMap::const_iterator I = WeakMap.begin(), E = WeakMap.end();
1390 I != E; ++I) {
1391 const WeakUseVector &Uses = I->second;
1392
1393 // Find the first read of the weak object.
1394 WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
1395 for ( ; UI != UE; ++UI) {
1396 if (UI->isUnsafe())
1397 break;
1398 }
1399
1400 // If there were only writes to this object, don't warn.
1401 if (UI == UE)
1402 continue;
1403
1404 // If there was only one read, followed by any number of writes, and the
1405 // read is not within a loop, don't warn. Additionally, don't warn in a
1406 // loop if the base object is a local variable -- local variables are often
1407 // changed in loops.
1408 if (UI == Uses.begin()) {
1409 WeakUseVector::const_iterator UI2 = UI;
1410 for (++UI2; UI2 != UE; ++UI2)
1411 if (UI2->isUnsafe())
1412 break;
1413
1414 if (UI2 == UE) {
1415 if (!isInLoop(Ctx, PM, UI->getUseExpr()))
1416 continue;
1417
1418 const WeakObjectProfileTy &Profile = I->first;
1419 if (!Profile.isExactProfile())
1420 continue;
1421
1422 const NamedDecl *Base = Profile.getBase();
1423 if (!Base)
1424 Base = Profile.getProperty();
1425 assert(Base && "A profile always has a base or property.");
1426
1427 if (const VarDecl *BaseVar = dyn_cast<VarDecl>(Val: Base))
1428 if (BaseVar->hasLocalStorage() && !isa<ParmVarDecl>(Val: Base))
1429 continue;
1430 }
1431 }
1432
1433 UsesByStmt.push_back(Elt: StmtUsesPair(UI->getUseExpr(), I));
1434 }
1435
1436 if (UsesByStmt.empty())
1437 return;
1438
1439 // Sort by first use so that we emit the warnings in a deterministic order.
1440 SourceManager &SM = S.getSourceManager();
1441 llvm::sort(C&: UsesByStmt,
1442 Comp: [&SM](const StmtUsesPair &LHS, const StmtUsesPair &RHS) {
1443 return SM.isBeforeInTranslationUnit(LHS: LHS.first->getBeginLoc(),
1444 RHS: RHS.first->getBeginLoc());
1445 });
1446
1447 // Classify the current code body for better warning text.
1448 // This enum should stay in sync with the cases in
1449 // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1450 // FIXME: Should we use a common classification enum and the same set of
1451 // possibilities all throughout Sema?
1452 enum {
1453 Function,
1454 Method,
1455 Block,
1456 Lambda
1457 } FunctionKind;
1458
1459 if (isa<sema::BlockScopeInfo>(Val: CurFn))
1460 FunctionKind = Block;
1461 else if (isa<sema::LambdaScopeInfo>(Val: CurFn))
1462 FunctionKind = Lambda;
1463 else if (isa<ObjCMethodDecl>(Val: D))
1464 FunctionKind = Method;
1465 else
1466 FunctionKind = Function;
1467
1468 // Iterate through the sorted problems and emit warnings for each.
1469 for (const auto &P : UsesByStmt) {
1470 const Stmt *FirstRead = P.first;
1471 const WeakObjectProfileTy &Key = P.second->first;
1472 const WeakUseVector &Uses = P.second->second;
1473
1474 // For complicated expressions like 'a.b.c' and 'x.b.c', WeakObjectProfileTy
1475 // may not contain enough information to determine that these are different
1476 // properties. We can only be 100% sure of a repeated use in certain cases,
1477 // and we adjust the diagnostic kind accordingly so that the less certain
1478 // case can be turned off if it is too noisy.
1479 unsigned DiagKind;
1480 if (Key.isExactProfile())
1481 DiagKind = diag::warn_arc_repeated_use_of_weak;
1482 else
1483 DiagKind = diag::warn_arc_possible_repeated_use_of_weak;
1484
1485 // Classify the weak object being accessed for better warning text.
1486 // This enum should stay in sync with the cases in
1487 // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1488 enum {
1489 Variable,
1490 Property,
1491 ImplicitProperty,
1492 Ivar
1493 } ObjectKind;
1494
1495 const NamedDecl *KeyProp = Key.getProperty();
1496 if (isa<VarDecl>(Val: KeyProp))
1497 ObjectKind = Variable;
1498 else if (isa<ObjCPropertyDecl>(Val: KeyProp))
1499 ObjectKind = Property;
1500 else if (isa<ObjCMethodDecl>(Val: KeyProp))
1501 ObjectKind = ImplicitProperty;
1502 else if (isa<ObjCIvarDecl>(Val: KeyProp))
1503 ObjectKind = Ivar;
1504 else
1505 llvm_unreachable("Unexpected weak object kind!");
1506
1507 // Do not warn about IBOutlet weak property receivers being set to null
1508 // since they are typically only used from the main thread.
1509 if (const ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(Val: KeyProp))
1510 if (Prop->hasAttr<IBOutletAttr>())
1511 continue;
1512
1513 // Show the first time the object was read.
1514 S.Diag(Loc: FirstRead->getBeginLoc(), DiagID: DiagKind)
1515 << int(ObjectKind) << KeyProp << int(FunctionKind)
1516 << FirstRead->getSourceRange();
1517
1518 // Print all the other accesses as notes.
1519 for (const auto &Use : Uses) {
1520 if (Use.getUseExpr() == FirstRead)
1521 continue;
1522 S.Diag(Use.getUseExpr()->getBeginLoc(),
1523 diag::note_arc_weak_also_accessed_here)
1524 << Use.getUseExpr()->getSourceRange();
1525 }
1526 }
1527}
1528
1529namespace clang {
1530namespace {
1531typedef SmallVector<PartialDiagnosticAt, 1> OptionalNotes;
1532typedef std::pair<PartialDiagnosticAt, OptionalNotes> DelayedDiag;
1533typedef std::list<DelayedDiag> DiagList;
1534
1535struct SortDiagBySourceLocation {
1536 SourceManager &SM;
1537 SortDiagBySourceLocation(SourceManager &SM) : SM(SM) {}
1538
1539 bool operator()(const DelayedDiag &left, const DelayedDiag &right) {
1540 // Although this call will be slow, this is only called when outputting
1541 // multiple warnings.
1542 return SM.isBeforeInTranslationUnit(LHS: left.first.first, RHS: right.first.first);
1543 }
1544};
1545} // anonymous namespace
1546} // namespace clang
1547
1548namespace {
1549class UninitValsDiagReporter : public UninitVariablesHandler {
1550 Sema &S;
1551 typedef SmallVector<UninitUse, 2> UsesVec;
1552 typedef llvm::PointerIntPair<UsesVec *, 1, bool> MappedType;
1553 // Prefer using MapVector to DenseMap, so that iteration order will be
1554 // the same as insertion order. This is needed to obtain a deterministic
1555 // order of diagnostics when calling flushDiagnostics().
1556 typedef llvm::MapVector<const VarDecl *, MappedType> UsesMap;
1557 UsesMap uses;
1558 UsesMap constRefUses;
1559
1560public:
1561 UninitValsDiagReporter(Sema &S) : S(S) {}
1562 ~UninitValsDiagReporter() override { flushDiagnostics(); }
1563
1564 MappedType &getUses(UsesMap &um, const VarDecl *vd) {
1565 MappedType &V = um[vd];
1566 if (!V.getPointer())
1567 V.setPointer(new UsesVec());
1568 return V;
1569 }
1570
1571 void handleUseOfUninitVariable(const VarDecl *vd,
1572 const UninitUse &use) override {
1573 getUses(um&: uses, vd).getPointer()->push_back(Elt: use);
1574 }
1575
1576 void handleConstRefUseOfUninitVariable(const VarDecl *vd,
1577 const UninitUse &use) override {
1578 getUses(um&: constRefUses, vd).getPointer()->push_back(Elt: use);
1579 }
1580
1581 void handleSelfInit(const VarDecl *vd) override {
1582 getUses(um&: uses, vd).setInt(true);
1583 getUses(um&: constRefUses, vd).setInt(true);
1584 }
1585
1586 void flushDiagnostics() {
1587 for (const auto &P : uses) {
1588 const VarDecl *vd = P.first;
1589 const MappedType &V = P.second;
1590
1591 UsesVec *vec = V.getPointer();
1592 bool hasSelfInit = V.getInt();
1593
1594 // Specially handle the case where we have uses of an uninitialized
1595 // variable, but the root cause is an idiomatic self-init. We want
1596 // to report the diagnostic at the self-init since that is the root cause.
1597 if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
1598 DiagnoseUninitializedUse(S, VD: vd,
1599 Use: UninitUse(vd->getInit()->IgnoreParenCasts(),
1600 /* isAlwaysUninit */ true),
1601 /* alwaysReportSelfInit */ true);
1602 else {
1603 // Sort the uses by their SourceLocations. While not strictly
1604 // guaranteed to produce them in line/column order, this will provide
1605 // a stable ordering.
1606 llvm::sort(C&: *vec, Comp: [](const UninitUse &a, const UninitUse &b) {
1607 // Prefer a more confident report over a less confident one.
1608 if (a.getKind() != b.getKind())
1609 return a.getKind() > b.getKind();
1610 return a.getUser()->getBeginLoc() < b.getUser()->getBeginLoc();
1611 });
1612
1613 for (const auto &U : *vec) {
1614 // If we have self-init, downgrade all uses to 'may be uninitialized'.
1615 UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
1616
1617 if (DiagnoseUninitializedUse(S, VD: vd, Use))
1618 // Skip further diagnostics for this variable. We try to warn only
1619 // on the first point at which a variable is used uninitialized.
1620 break;
1621 }
1622 }
1623
1624 // Release the uses vector.
1625 delete vec;
1626 }
1627
1628 uses.clear();
1629
1630 // Flush all const reference uses diags.
1631 for (const auto &P : constRefUses) {
1632 const VarDecl *vd = P.first;
1633 const MappedType &V = P.second;
1634
1635 UsesVec *vec = V.getPointer();
1636 bool hasSelfInit = V.getInt();
1637
1638 if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
1639 DiagnoseUninitializedUse(S, VD: vd,
1640 Use: UninitUse(vd->getInit()->IgnoreParenCasts(),
1641 /* isAlwaysUninit */ true),
1642 /* alwaysReportSelfInit */ true);
1643 else {
1644 for (const auto &U : *vec) {
1645 if (DiagnoseUninitializedConstRefUse(S, VD: vd, Use: U))
1646 break;
1647 }
1648 }
1649
1650 // Release the uses vector.
1651 delete vec;
1652 }
1653
1654 constRefUses.clear();
1655 }
1656
1657private:
1658 static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
1659 return llvm::any_of(Range: *vec, P: [](const UninitUse &U) {
1660 return U.getKind() == UninitUse::Always ||
1661 U.getKind() == UninitUse::AfterCall ||
1662 U.getKind() == UninitUse::AfterDecl;
1663 });
1664 }
1665};
1666
1667/// Inter-procedural data for the called-once checker.
1668class CalledOnceInterProceduralData {
1669public:
1670 // Add the delayed warning for the given block.
1671 void addDelayedWarning(const BlockDecl *Block,
1672 PartialDiagnosticAt &&Warning) {
1673 DelayedBlockWarnings[Block].emplace_back(Args: std::move(Warning));
1674 }
1675 // Report all of the warnings we've gathered for the given block.
1676 void flushWarnings(const BlockDecl *Block, Sema &S) {
1677 for (const PartialDiagnosticAt &Delayed : DelayedBlockWarnings[Block])
1678 S.Diag(Loc: Delayed.first, PD: Delayed.second);
1679
1680 discardWarnings(Block);
1681 }
1682 // Discard all of the warnings we've gathered for the given block.
1683 void discardWarnings(const BlockDecl *Block) {
1684 DelayedBlockWarnings.erase(Val: Block);
1685 }
1686
1687private:
1688 using DelayedDiagnostics = SmallVector<PartialDiagnosticAt, 2>;
1689 llvm::DenseMap<const BlockDecl *, DelayedDiagnostics> DelayedBlockWarnings;
1690};
1691
1692class CalledOnceCheckReporter : public CalledOnceCheckHandler {
1693public:
1694 CalledOnceCheckReporter(Sema &S, CalledOnceInterProceduralData &Data)
1695 : S(S), Data(Data) {}
1696 void handleDoubleCall(const ParmVarDecl *Parameter, const Expr *Call,
1697 const Expr *PrevCall, bool IsCompletionHandler,
1698 bool Poised) override {
1699 auto DiagToReport = IsCompletionHandler
1700 ? diag::warn_completion_handler_called_twice
1701 : diag::warn_called_once_gets_called_twice;
1702 S.Diag(Call->getBeginLoc(), DiagToReport) << Parameter;
1703 S.Diag(PrevCall->getBeginLoc(), diag::note_called_once_gets_called_twice)
1704 << Poised;
1705 }
1706
1707 void handleNeverCalled(const ParmVarDecl *Parameter,
1708 bool IsCompletionHandler) override {
1709 auto DiagToReport = IsCompletionHandler
1710 ? diag::warn_completion_handler_never_called
1711 : diag::warn_called_once_never_called;
1712 S.Diag(Parameter->getBeginLoc(), DiagToReport)
1713 << Parameter << /* Captured */ false;
1714 }
1715
1716 void handleNeverCalled(const ParmVarDecl *Parameter, const Decl *Function,
1717 const Stmt *Where, NeverCalledReason Reason,
1718 bool IsCalledDirectly,
1719 bool IsCompletionHandler) override {
1720 auto DiagToReport = IsCompletionHandler
1721 ? diag::warn_completion_handler_never_called_when
1722 : diag::warn_called_once_never_called_when;
1723 PartialDiagnosticAt Warning(Where->getBeginLoc(), S.PDiag(DiagID: DiagToReport)
1724 << Parameter
1725 << IsCalledDirectly
1726 << (unsigned)Reason);
1727
1728 if (const auto *Block = dyn_cast<BlockDecl>(Val: Function)) {
1729 // We shouldn't report these warnings on blocks immediately
1730 Data.addDelayedWarning(Block, Warning: std::move(Warning));
1731 } else {
1732 S.Diag(Loc: Warning.first, PD: Warning.second);
1733 }
1734 }
1735
1736 void handleCapturedNeverCalled(const ParmVarDecl *Parameter,
1737 const Decl *Where,
1738 bool IsCompletionHandler) override {
1739 auto DiagToReport = IsCompletionHandler
1740 ? diag::warn_completion_handler_never_called
1741 : diag::warn_called_once_never_called;
1742 S.Diag(Where->getBeginLoc(), DiagToReport)
1743 << Parameter << /* Captured */ true;
1744 }
1745
1746 void
1747 handleBlockThatIsGuaranteedToBeCalledOnce(const BlockDecl *Block) override {
1748 Data.flushWarnings(Block, S);
1749 }
1750
1751 void handleBlockWithNoGuarantees(const BlockDecl *Block) override {
1752 Data.discardWarnings(Block);
1753 }
1754
1755private:
1756 Sema &S;
1757 CalledOnceInterProceduralData &Data;
1758};
1759
1760constexpr unsigned CalledOnceWarnings[] = {
1761 diag::warn_called_once_never_called,
1762 diag::warn_called_once_never_called_when,
1763 diag::warn_called_once_gets_called_twice};
1764
1765constexpr unsigned CompletionHandlerWarnings[]{
1766 diag::warn_completion_handler_never_called,
1767 diag::warn_completion_handler_never_called_when,
1768 diag::warn_completion_handler_called_twice};
1769
1770bool shouldAnalyzeCalledOnceImpl(llvm::ArrayRef<unsigned> DiagIDs,
1771 const DiagnosticsEngine &Diags,
1772 SourceLocation At) {
1773 return llvm::any_of(Range&: DiagIDs, P: [&Diags, At](unsigned DiagID) {
1774 return !Diags.isIgnored(DiagID, Loc: At);
1775 });
1776}
1777
1778bool shouldAnalyzeCalledOnceConventions(const DiagnosticsEngine &Diags,
1779 SourceLocation At) {
1780 return shouldAnalyzeCalledOnceImpl(CompletionHandlerWarnings, Diags, At);
1781}
1782
1783bool shouldAnalyzeCalledOnceParameters(const DiagnosticsEngine &Diags,
1784 SourceLocation At) {
1785 return shouldAnalyzeCalledOnceImpl(CalledOnceWarnings, Diags, At) ||
1786 shouldAnalyzeCalledOnceConventions(Diags, At);
1787}
1788} // anonymous namespace
1789
1790//===----------------------------------------------------------------------===//
1791// -Wthread-safety
1792//===----------------------------------------------------------------------===//
1793namespace clang {
1794namespace threadSafety {
1795namespace {
1796class ThreadSafetyReporter : public clang::threadSafety::ThreadSafetyHandler {
1797 Sema &S;
1798 DiagList Warnings;
1799 SourceLocation FunLocation, FunEndLocation;
1800
1801 const FunctionDecl *CurrentFunction;
1802 bool Verbose;
1803
1804 OptionalNotes getNotes() const {
1805 if (Verbose && CurrentFunction) {
1806 PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1807 S.PDiag(diag::note_thread_warning_in_fun)
1808 << CurrentFunction);
1809 return OptionalNotes(1, FNote);
1810 }
1811 return OptionalNotes();
1812 }
1813
1814 OptionalNotes getNotes(const PartialDiagnosticAt &Note) const {
1815 OptionalNotes ONS(1, Note);
1816 if (Verbose && CurrentFunction) {
1817 PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1818 S.PDiag(diag::note_thread_warning_in_fun)
1819 << CurrentFunction);
1820 ONS.push_back(Elt: std::move(FNote));
1821 }
1822 return ONS;
1823 }
1824
1825 OptionalNotes getNotes(const PartialDiagnosticAt &Note1,
1826 const PartialDiagnosticAt &Note2) const {
1827 OptionalNotes ONS;
1828 ONS.push_back(Elt: Note1);
1829 ONS.push_back(Elt: Note2);
1830 if (Verbose && CurrentFunction) {
1831 PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1832 S.PDiag(diag::note_thread_warning_in_fun)
1833 << CurrentFunction);
1834 ONS.push_back(Elt: std::move(FNote));
1835 }
1836 return ONS;
1837 }
1838
1839 OptionalNotes makeLockedHereNote(SourceLocation LocLocked, StringRef Kind) {
1840 return LocLocked.isValid()
1841 ? getNotes(PartialDiagnosticAt(
1842 LocLocked, S.PDiag(diag::note_locked_here) << Kind))
1843 : getNotes();
1844 }
1845
1846 OptionalNotes makeUnlockedHereNote(SourceLocation LocUnlocked,
1847 StringRef Kind) {
1848 return LocUnlocked.isValid()
1849 ? getNotes(PartialDiagnosticAt(
1850 LocUnlocked, S.PDiag(diag::note_unlocked_here) << Kind))
1851 : getNotes();
1852 }
1853
1854 public:
1855 ThreadSafetyReporter(Sema &S, SourceLocation FL, SourceLocation FEL)
1856 : S(S), FunLocation(FL), FunEndLocation(FEL),
1857 CurrentFunction(nullptr), Verbose(false) {}
1858
1859 void setVerbose(bool b) { Verbose = b; }
1860
1861 /// Emit all buffered diagnostics in order of sourcelocation.
1862 /// We need to output diagnostics produced while iterating through
1863 /// the lockset in deterministic order, so this function orders diagnostics
1864 /// and outputs them.
1865 void emitDiagnostics() {
1866 Warnings.sort(comp: SortDiagBySourceLocation(S.getSourceManager()));
1867 for (const auto &Diag : Warnings) {
1868 S.Diag(Loc: Diag.first.first, PD: Diag.first.second);
1869 for (const auto &Note : Diag.second)
1870 S.Diag(Loc: Note.first, PD: Note.second);
1871 }
1872 }
1873
1874 void handleInvalidLockExp(SourceLocation Loc) override {
1875 PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_cannot_resolve_lock)
1876 << Loc);
1877 Warnings.emplace_back(args: std::move(Warning), args: getNotes());
1878 }
1879
1880 void handleUnmatchedUnlock(StringRef Kind, Name LockName, SourceLocation Loc,
1881 SourceLocation LocPreviousUnlock) override {
1882 if (Loc.isInvalid())
1883 Loc = FunLocation;
1884 PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_unlock_but_no_lock)
1885 << Kind << LockName);
1886 Warnings.emplace_back(args: std::move(Warning),
1887 args: makeUnlockedHereNote(LocUnlocked: LocPreviousUnlock, Kind));
1888 }
1889
1890 void handleIncorrectUnlockKind(StringRef Kind, Name LockName,
1891 LockKind Expected, LockKind Received,
1892 SourceLocation LocLocked,
1893 SourceLocation LocUnlock) override {
1894 if (LocUnlock.isInvalid())
1895 LocUnlock = FunLocation;
1896 PartialDiagnosticAt Warning(
1897 LocUnlock, S.PDiag(diag::warn_unlock_kind_mismatch)
1898 << Kind << LockName << Received << Expected);
1899 Warnings.emplace_back(args: std::move(Warning),
1900 args: makeLockedHereNote(LocLocked, Kind));
1901 }
1902
1903 void handleDoubleLock(StringRef Kind, Name LockName, SourceLocation LocLocked,
1904 SourceLocation LocDoubleLock) override {
1905 if (LocDoubleLock.isInvalid())
1906 LocDoubleLock = FunLocation;
1907 PartialDiagnosticAt Warning(LocDoubleLock, S.PDiag(diag::warn_double_lock)
1908 << Kind << LockName);
1909 Warnings.emplace_back(args: std::move(Warning),
1910 args: makeLockedHereNote(LocLocked, Kind));
1911 }
1912
1913 void handleMutexHeldEndOfScope(StringRef Kind, Name LockName,
1914 SourceLocation LocLocked,
1915 SourceLocation LocEndOfScope,
1916 LockErrorKind LEK) override {
1917 unsigned DiagID = 0;
1918 switch (LEK) {
1919 case LEK_LockedSomePredecessors:
1920 DiagID = diag::warn_lock_some_predecessors;
1921 break;
1922 case LEK_LockedSomeLoopIterations:
1923 DiagID = diag::warn_expecting_lock_held_on_loop;
1924 break;
1925 case LEK_LockedAtEndOfFunction:
1926 DiagID = diag::warn_no_unlock;
1927 break;
1928 case LEK_NotLockedAtEndOfFunction:
1929 DiagID = diag::warn_expecting_locked;
1930 break;
1931 }
1932 if (LocEndOfScope.isInvalid())
1933 LocEndOfScope = FunEndLocation;
1934
1935 PartialDiagnosticAt Warning(LocEndOfScope, S.PDiag(DiagID) << Kind
1936 << LockName);
1937 Warnings.emplace_back(args: std::move(Warning),
1938 args: makeLockedHereNote(LocLocked, Kind));
1939 }
1940
1941 void handleExclusiveAndShared(StringRef Kind, Name LockName,
1942 SourceLocation Loc1,
1943 SourceLocation Loc2) override {
1944 PartialDiagnosticAt Warning(Loc1,
1945 S.PDiag(diag::warn_lock_exclusive_and_shared)
1946 << Kind << LockName);
1947 PartialDiagnosticAt Note(Loc2, S.PDiag(diag::note_lock_exclusive_and_shared)
1948 << Kind << LockName);
1949 Warnings.emplace_back(args: std::move(Warning), args: getNotes(Note));
1950 }
1951
1952 void handleNoMutexHeld(const NamedDecl *D, ProtectedOperationKind POK,
1953 AccessKind AK, SourceLocation Loc) override {
1954 assert((POK == POK_VarAccess || POK == POK_VarDereference) &&
1955 "Only works for variables");
1956 unsigned DiagID = POK == POK_VarAccess?
1957 diag::warn_variable_requires_any_lock:
1958 diag::warn_var_deref_requires_any_lock;
1959 PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
1960 << D << getLockKindFromAccessKind(AK));
1961 Warnings.emplace_back(args: std::move(Warning), args: getNotes());
1962 }
1963
1964 void handleMutexNotHeld(StringRef Kind, const NamedDecl *D,
1965 ProtectedOperationKind POK, Name LockName,
1966 LockKind LK, SourceLocation Loc,
1967 Name *PossibleMatch) override {
1968 unsigned DiagID = 0;
1969 if (PossibleMatch) {
1970 switch (POK) {
1971 case POK_VarAccess:
1972 DiagID = diag::warn_variable_requires_lock_precise;
1973 break;
1974 case POK_VarDereference:
1975 DiagID = diag::warn_var_deref_requires_lock_precise;
1976 break;
1977 case POK_FunctionCall:
1978 DiagID = diag::warn_fun_requires_lock_precise;
1979 break;
1980 case POK_PassByRef:
1981 DiagID = diag::warn_guarded_pass_by_reference;
1982 break;
1983 case POK_PtPassByRef:
1984 DiagID = diag::warn_pt_guarded_pass_by_reference;
1985 break;
1986 case POK_ReturnByRef:
1987 DiagID = diag::warn_guarded_return_by_reference;
1988 break;
1989 case POK_PtReturnByRef:
1990 DiagID = diag::warn_pt_guarded_return_by_reference;
1991 break;
1992 }
1993 PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1994 << D
1995 << LockName << LK);
1996 PartialDiagnosticAt Note(Loc, S.PDiag(diag::note_found_mutex_near_match)
1997 << *PossibleMatch);
1998 if (Verbose && POK == POK_VarAccess) {
1999 PartialDiagnosticAt VNote(D->getLocation(),
2000 S.PDiag(diag::note_guarded_by_declared_here)
2001 << D->getDeclName());
2002 Warnings.emplace_back(args: std::move(Warning), args: getNotes(Note1: Note, Note2: VNote));
2003 } else
2004 Warnings.emplace_back(args: std::move(Warning), args: getNotes(Note));
2005 } else {
2006 switch (POK) {
2007 case POK_VarAccess:
2008 DiagID = diag::warn_variable_requires_lock;
2009 break;
2010 case POK_VarDereference:
2011 DiagID = diag::warn_var_deref_requires_lock;
2012 break;
2013 case POK_FunctionCall:
2014 DiagID = diag::warn_fun_requires_lock;
2015 break;
2016 case POK_PassByRef:
2017 DiagID = diag::warn_guarded_pass_by_reference;
2018 break;
2019 case POK_PtPassByRef:
2020 DiagID = diag::warn_pt_guarded_pass_by_reference;
2021 break;
2022 case POK_ReturnByRef:
2023 DiagID = diag::warn_guarded_return_by_reference;
2024 break;
2025 case POK_PtReturnByRef:
2026 DiagID = diag::warn_pt_guarded_return_by_reference;
2027 break;
2028 }
2029 PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
2030 << D
2031 << LockName << LK);
2032 if (Verbose && POK == POK_VarAccess) {
2033 PartialDiagnosticAt Note(D->getLocation(),
2034 S.PDiag(diag::note_guarded_by_declared_here));
2035 Warnings.emplace_back(args: std::move(Warning), args: getNotes(Note));
2036 } else
2037 Warnings.emplace_back(args: std::move(Warning), args: getNotes());
2038 }
2039 }
2040
2041 void handleNegativeNotHeld(StringRef Kind, Name LockName, Name Neg,
2042 SourceLocation Loc) override {
2043 PartialDiagnosticAt Warning(Loc,
2044 S.PDiag(diag::warn_acquire_requires_negative_cap)
2045 << Kind << LockName << Neg);
2046 Warnings.emplace_back(args: std::move(Warning), args: getNotes());
2047 }
2048
2049 void handleNegativeNotHeld(const NamedDecl *D, Name LockName,
2050 SourceLocation Loc) override {
2051 PartialDiagnosticAt Warning(
2052 Loc, S.PDiag(diag::warn_fun_requires_negative_cap) << D << LockName);
2053 Warnings.emplace_back(args: std::move(Warning), args: getNotes());
2054 }
2055
2056 void handleFunExcludesLock(StringRef Kind, Name FunName, Name LockName,
2057 SourceLocation Loc) override {
2058 PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_fun_excludes_mutex)
2059 << Kind << FunName << LockName);
2060 Warnings.emplace_back(args: std::move(Warning), args: getNotes());
2061 }
2062
2063 void handleLockAcquiredBefore(StringRef Kind, Name L1Name, Name L2Name,
2064 SourceLocation Loc) override {
2065 PartialDiagnosticAt Warning(Loc,
2066 S.PDiag(diag::warn_acquired_before) << Kind << L1Name << L2Name);
2067 Warnings.emplace_back(args: std::move(Warning), args: getNotes());
2068 }
2069
2070 void handleBeforeAfterCycle(Name L1Name, SourceLocation Loc) override {
2071 PartialDiagnosticAt Warning(Loc,
2072 S.PDiag(diag::warn_acquired_before_after_cycle) << L1Name);
2073 Warnings.emplace_back(args: std::move(Warning), args: getNotes());
2074 }
2075
2076 void enterFunction(const FunctionDecl* FD) override {
2077 CurrentFunction = FD;
2078 }
2079
2080 void leaveFunction(const FunctionDecl* FD) override {
2081 CurrentFunction = nullptr;
2082 }
2083};
2084} // anonymous namespace
2085} // namespace threadSafety
2086} // namespace clang
2087
2088//===----------------------------------------------------------------------===//
2089// -Wconsumed
2090//===----------------------------------------------------------------------===//
2091
2092namespace clang {
2093namespace consumed {
2094namespace {
2095class ConsumedWarningsHandler : public ConsumedWarningsHandlerBase {
2096
2097 Sema &S;
2098 DiagList Warnings;
2099
2100public:
2101
2102 ConsumedWarningsHandler(Sema &S) : S(S) {}
2103
2104 void emitDiagnostics() override {
2105 Warnings.sort(comp: SortDiagBySourceLocation(S.getSourceManager()));
2106 for (const auto &Diag : Warnings) {
2107 S.Diag(Loc: Diag.first.first, PD: Diag.first.second);
2108 for (const auto &Note : Diag.second)
2109 S.Diag(Loc: Note.first, PD: Note.second);
2110 }
2111 }
2112
2113 void warnLoopStateMismatch(SourceLocation Loc,
2114 StringRef VariableName) override {
2115 PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_loop_state_mismatch) <<
2116 VariableName);
2117
2118 Warnings.emplace_back(args: std::move(Warning), args: OptionalNotes());
2119 }
2120
2121 void warnParamReturnTypestateMismatch(SourceLocation Loc,
2122 StringRef VariableName,
2123 StringRef ExpectedState,
2124 StringRef ObservedState) override {
2125
2126 PartialDiagnosticAt Warning(Loc, S.PDiag(
2127 diag::warn_param_return_typestate_mismatch) << VariableName <<
2128 ExpectedState << ObservedState);
2129
2130 Warnings.emplace_back(args: std::move(Warning), args: OptionalNotes());
2131 }
2132
2133 void warnParamTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
2134 StringRef ObservedState) override {
2135
2136 PartialDiagnosticAt Warning(Loc, S.PDiag(
2137 diag::warn_param_typestate_mismatch) << ExpectedState << ObservedState);
2138
2139 Warnings.emplace_back(args: std::move(Warning), args: OptionalNotes());
2140 }
2141
2142 void warnReturnTypestateForUnconsumableType(SourceLocation Loc,
2143 StringRef TypeName) override {
2144 PartialDiagnosticAt Warning(Loc, S.PDiag(
2145 diag::warn_return_typestate_for_unconsumable_type) << TypeName);
2146
2147 Warnings.emplace_back(args: std::move(Warning), args: OptionalNotes());
2148 }
2149
2150 void warnReturnTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
2151 StringRef ObservedState) override {
2152
2153 PartialDiagnosticAt Warning(Loc, S.PDiag(
2154 diag::warn_return_typestate_mismatch) << ExpectedState << ObservedState);
2155
2156 Warnings.emplace_back(args: std::move(Warning), args: OptionalNotes());
2157 }
2158
2159 void warnUseOfTempInInvalidState(StringRef MethodName, StringRef State,
2160 SourceLocation Loc) override {
2161
2162 PartialDiagnosticAt Warning(Loc, S.PDiag(
2163 diag::warn_use_of_temp_in_invalid_state) << MethodName << State);
2164
2165 Warnings.emplace_back(args: std::move(Warning), args: OptionalNotes());
2166 }
2167
2168 void warnUseInInvalidState(StringRef MethodName, StringRef VariableName,
2169 StringRef State, SourceLocation Loc) override {
2170
2171 PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_use_in_invalid_state) <<
2172 MethodName << VariableName << State);
2173
2174 Warnings.emplace_back(args: std::move(Warning), args: OptionalNotes());
2175 }
2176};
2177} // anonymous namespace
2178} // namespace consumed
2179} // namespace clang
2180
2181//===----------------------------------------------------------------------===//
2182// Unsafe buffer usage analysis.
2183//===----------------------------------------------------------------------===//
2184
2185namespace {
2186class UnsafeBufferUsageReporter : public UnsafeBufferUsageHandler {
2187 Sema &S;
2188 bool SuggestSuggestions; // Recommend -fsafe-buffer-usage-suggestions?
2189
2190 // Lists as a string the names of variables in `VarGroupForVD` except for `VD`
2191 // itself:
2192 std::string listVariableGroupAsString(
2193 const VarDecl *VD, const ArrayRef<const VarDecl *> &VarGroupForVD) const {
2194 if (VarGroupForVD.size() <= 1)
2195 return "";
2196
2197 std::vector<StringRef> VarNames;
2198 auto PutInQuotes = [](StringRef S) -> std::string {
2199 return "'" + S.str() + "'";
2200 };
2201
2202 for (auto *V : VarGroupForVD) {
2203 if (V == VD)
2204 continue;
2205 VarNames.push_back(V->getName());
2206 }
2207 if (VarNames.size() == 1) {
2208 return PutInQuotes(VarNames[0]);
2209 }
2210 if (VarNames.size() == 2) {
2211 return PutInQuotes(VarNames[0]) + " and " + PutInQuotes(VarNames[1]);
2212 }
2213 assert(VarGroupForVD.size() > 3);
2214 const unsigned N = VarNames.size() -
2215 2; // need to print the last two names as "..., X, and Y"
2216 std::string AllVars = "";
2217
2218 for (unsigned I = 0; I < N; ++I)
2219 AllVars.append(str: PutInQuotes(VarNames[I]) + ", ");
2220 AllVars.append(str: PutInQuotes(VarNames[N]) + ", and " +
2221 PutInQuotes(VarNames[N + 1]));
2222 return AllVars;
2223 }
2224
2225public:
2226 UnsafeBufferUsageReporter(Sema &S, bool SuggestSuggestions)
2227 : S(S), SuggestSuggestions(SuggestSuggestions) {}
2228
2229 void handleUnsafeOperation(const Stmt *Operation, bool IsRelatedToDecl,
2230 ASTContext &Ctx) override {
2231 SourceLocation Loc;
2232 SourceRange Range;
2233 unsigned MsgParam = 0;
2234 if (const auto *ASE = dyn_cast<ArraySubscriptExpr>(Val: Operation)) {
2235 Loc = ASE->getBase()->getExprLoc();
2236 Range = ASE->getBase()->getSourceRange();
2237 MsgParam = 2;
2238 } else if (const auto *BO = dyn_cast<BinaryOperator>(Val: Operation)) {
2239 BinaryOperator::Opcode Op = BO->getOpcode();
2240 if (Op == BO_Add || Op == BO_AddAssign || Op == BO_Sub ||
2241 Op == BO_SubAssign) {
2242 if (BO->getRHS()->getType()->isIntegerType()) {
2243 Loc = BO->getLHS()->getExprLoc();
2244 Range = BO->getLHS()->getSourceRange();
2245 } else {
2246 Loc = BO->getRHS()->getExprLoc();
2247 Range = BO->getRHS()->getSourceRange();
2248 }
2249 MsgParam = 1;
2250 }
2251 } else if (const auto *UO = dyn_cast<UnaryOperator>(Val: Operation)) {
2252 UnaryOperator::Opcode Op = UO->getOpcode();
2253 if (Op == UO_PreInc || Op == UO_PreDec || Op == UO_PostInc ||
2254 Op == UO_PostDec) {
2255 Loc = UO->getSubExpr()->getExprLoc();
2256 Range = UO->getSubExpr()->getSourceRange();
2257 MsgParam = 1;
2258 }
2259 } else if (const auto *CtorExpr = dyn_cast<CXXConstructExpr>(Val: Operation)) {
2260 S.Diag(CtorExpr->getLocation(),
2261 diag::warn_unsafe_buffer_usage_in_container);
2262 } else {
2263 if (isa<CallExpr>(Val: Operation)) {
2264 // note_unsafe_buffer_operation doesn't have this mode yet.
2265 assert(!IsRelatedToDecl && "Not implemented yet!");
2266 MsgParam = 3;
2267 } else if (const auto *ECE = dyn_cast<ExplicitCastExpr>(Val: Operation)) {
2268 QualType destType = ECE->getType();
2269 if (!isa<PointerType>(Val: destType))
2270 return;
2271
2272 const uint64_t dSize =
2273 Ctx.getTypeSize(T: destType.getTypePtr()->getPointeeType());
2274
2275 QualType srcType = ECE->getSubExpr()->getType();
2276 const uint64_t sSize =
2277 Ctx.getTypeSize(T: srcType.getTypePtr()->getPointeeType());
2278 if (sSize >= dSize)
2279 return;
2280
2281 MsgParam = 4;
2282 }
2283 Loc = Operation->getBeginLoc();
2284 Range = Operation->getSourceRange();
2285 }
2286 if (IsRelatedToDecl) {
2287 assert(!SuggestSuggestions &&
2288 "Variables blamed for unsafe buffer usage without suggestions!");
2289 S.Diag(Loc, diag::note_unsafe_buffer_operation) << MsgParam << Range;
2290 } else {
2291 S.Diag(Loc, diag::warn_unsafe_buffer_operation) << MsgParam << Range;
2292 if (SuggestSuggestions) {
2293 S.Diag(Loc, diag::note_safe_buffer_usage_suggestions_disabled);
2294 }
2295 }
2296 }
2297
2298 void handleUnsafeVariableGroup(const VarDecl *Variable,
2299 const VariableGroupsManager &VarGrpMgr,
2300 FixItList &&Fixes, const Decl *D,
2301 const FixitStrategy &VarTargetTypes) override {
2302 assert(!SuggestSuggestions &&
2303 "Unsafe buffer usage fixits displayed without suggestions!");
2304 S.Diag(Variable->getLocation(), diag::warn_unsafe_buffer_variable)
2305 << Variable << (Variable->getType()->isPointerType() ? 0 : 1)
2306 << Variable->getSourceRange();
2307 if (!Fixes.empty()) {
2308 assert(isa<NamedDecl>(D) &&
2309 "Fix-its are generated only for `NamedDecl`s");
2310 const NamedDecl *ND = cast<NamedDecl>(Val: D);
2311 bool BriefMsg = false;
2312 // If the variable group involves parameters, the diagnostic message will
2313 // NOT explain how the variables are grouped as the reason is non-trivial
2314 // and irrelavant to users' experience:
2315 const auto VarGroupForVD = VarGrpMgr.getGroupOfVar(Var: Variable, HasParm: &BriefMsg);
2316 unsigned FixItStrategy = 0;
2317 switch (VarTargetTypes.lookup(VD: Variable)) {
2318 case clang::FixitStrategy::Kind::Span:
2319 FixItStrategy = 0;
2320 break;
2321 case clang::FixitStrategy::Kind::Array:
2322 FixItStrategy = 1;
2323 break;
2324 default:
2325 assert(false && "We support only std::span and std::array");
2326 };
2327
2328 const auto &FD =
2329 S.Diag(Variable->getLocation(),
2330 BriefMsg ? diag::note_unsafe_buffer_variable_fixit_together
2331 : diag::note_unsafe_buffer_variable_fixit_group);
2332
2333 FD << Variable << FixItStrategy;
2334 FD << listVariableGroupAsString(VD: Variable, VarGroupForVD)
2335 << (VarGroupForVD.size() > 1) << ND;
2336 for (const auto &F : Fixes) {
2337 FD << F;
2338 }
2339 }
2340
2341#ifndef NDEBUG
2342 if (areDebugNotesRequested())
2343 for (const DebugNote &Note: DebugNotesByVar[Variable])
2344 S.Diag(Note.first, diag::note_safe_buffer_debug_mode) << Note.second;
2345#endif
2346 }
2347
2348 bool isSafeBufferOptOut(const SourceLocation &Loc) const override {
2349 return S.PP.isSafeBufferOptOut(SourceMgr: S.getSourceManager(), Loc);
2350 }
2351
2352 bool ignoreUnsafeBufferInContainer(const SourceLocation &Loc) const override {
2353 return S.Diags.isIgnored(diag::warn_unsafe_buffer_usage_in_container, Loc);
2354 }
2355
2356 // Returns the text representation of clang::unsafe_buffer_usage attribute.
2357 // `WSSuffix` holds customized "white-space"s, e.g., newline or whilespace
2358 // characters.
2359 std::string
2360 getUnsafeBufferUsageAttributeTextAt(SourceLocation Loc,
2361 StringRef WSSuffix = "") const override {
2362 Preprocessor &PP = S.getPreprocessor();
2363 TokenValue ClangUnsafeBufferUsageTokens[] = {
2364 tok::l_square,
2365 tok::l_square,
2366 PP.getIdentifierInfo(Name: "clang"),
2367 tok::coloncolon,
2368 PP.getIdentifierInfo(Name: "unsafe_buffer_usage"),
2369 tok::r_square,
2370 tok::r_square};
2371
2372 StringRef MacroName;
2373
2374 // The returned macro (it returns) is guaranteed not to be function-like:
2375 MacroName = PP.getLastMacroWithSpelling(Loc, Tokens: ClangUnsafeBufferUsageTokens);
2376 if (MacroName.empty())
2377 MacroName = "[[clang::unsafe_buffer_usage]]";
2378 return MacroName.str() + WSSuffix.str();
2379 }
2380};
2381} // namespace
2382
2383//===----------------------------------------------------------------------===//
2384// AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
2385// warnings on a function, method, or block.
2386//===----------------------------------------------------------------------===//
2387
2388sema::AnalysisBasedWarnings::Policy::Policy() {
2389 enableCheckFallThrough = 1;
2390 enableCheckUnreachable = 0;
2391 enableThreadSafetyAnalysis = 0;
2392 enableConsumedAnalysis = 0;
2393}
2394
2395/// InterProceduralData aims to be a storage of whatever data should be passed
2396/// between analyses of different functions.
2397///
2398/// At the moment, its primary goal is to make the information gathered during
2399/// the analysis of the blocks available during the analysis of the enclosing
2400/// function. This is important due to the fact that blocks are analyzed before
2401/// the enclosed function is even parsed fully, so it is not viable to access
2402/// anything in the outer scope while analyzing the block. On the other hand,
2403/// re-building CFG for blocks and re-analyzing them when we do have all the
2404/// information (i.e. during the analysis of the enclosing function) seems to be
2405/// ill-designed.
2406class sema::AnalysisBasedWarnings::InterProceduralData {
2407public:
2408 // It is important to analyze blocks within functions because it's a very
2409 // common pattern to capture completion handler parameters by blocks.
2410 CalledOnceInterProceduralData CalledOnceData;
2411};
2412
2413static unsigned isEnabled(DiagnosticsEngine &D, unsigned diag) {
2414 return (unsigned)!D.isIgnored(DiagID: diag, Loc: SourceLocation());
2415}
2416
2417sema::AnalysisBasedWarnings::AnalysisBasedWarnings(Sema &s)
2418 : S(s), IPData(std::make_unique<InterProceduralData>()),
2419 NumFunctionsAnalyzed(0), NumFunctionsWithBadCFGs(0), NumCFGBlocks(0),
2420 MaxCFGBlocksPerFunction(0), NumUninitAnalysisFunctions(0),
2421 NumUninitAnalysisVariables(0), MaxUninitAnalysisVariablesPerFunction(0),
2422 NumUninitAnalysisBlockVisits(0),
2423 MaxUninitAnalysisBlockVisitsPerFunction(0) {
2424
2425 using namespace diag;
2426 DiagnosticsEngine &D = S.getDiagnostics();
2427
2428 DefaultPolicy.enableCheckUnreachable =
2429 isEnabled(D, warn_unreachable) || isEnabled(D, warn_unreachable_break) ||
2430 isEnabled(D, warn_unreachable_return) ||
2431 isEnabled(D, warn_unreachable_loop_increment);
2432
2433 DefaultPolicy.enableThreadSafetyAnalysis = isEnabled(D, warn_double_lock);
2434
2435 DefaultPolicy.enableConsumedAnalysis =
2436 isEnabled(D, warn_use_in_invalid_state);
2437}
2438
2439// We need this here for unique_ptr with forward declared class.
2440sema::AnalysisBasedWarnings::~AnalysisBasedWarnings() = default;
2441
2442static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope) {
2443 for (const auto &D : fscope->PossiblyUnreachableDiags)
2444 S.Diag(Loc: D.Loc, PD: D.PD);
2445}
2446
2447// An AST Visitor that calls a callback function on each callable DEFINITION
2448// that is NOT in a dependent context:
2449class CallableVisitor : public RecursiveASTVisitor<CallableVisitor> {
2450private:
2451 llvm::function_ref<void(const Decl *)> Callback;
2452
2453public:
2454 CallableVisitor(llvm::function_ref<void(const Decl *)> Callback)
2455 : Callback(Callback) {}
2456
2457 bool VisitFunctionDecl(FunctionDecl *Node) {
2458 if (cast<DeclContext>(Val: Node)->isDependentContext())
2459 return true; // Not to analyze dependent decl
2460 // `FunctionDecl->hasBody()` returns true if the function has a body
2461 // somewhere defined. But we want to know if this `Node` has a body
2462 // child. So we use `doesThisDeclarationHaveABody`:
2463 if (Node->doesThisDeclarationHaveABody())
2464 Callback(Node);
2465 return true;
2466 }
2467
2468 bool VisitBlockDecl(BlockDecl *Node) {
2469 if (cast<DeclContext>(Val: Node)->isDependentContext())
2470 return true; // Not to analyze dependent decl
2471 Callback(Node);
2472 return true;
2473 }
2474
2475 bool VisitObjCMethodDecl(ObjCMethodDecl *Node) {
2476 if (cast<DeclContext>(Val: Node)->isDependentContext())
2477 return true; // Not to analyze dependent decl
2478 if (Node->hasBody())
2479 Callback(Node);
2480 return true;
2481 }
2482
2483 bool VisitLambdaExpr(LambdaExpr *Node) {
2484 return VisitFunctionDecl(Node->getCallOperator());
2485 }
2486
2487 bool shouldVisitTemplateInstantiations() const { return true; }
2488 bool shouldVisitImplicitCode() const { return false; }
2489};
2490
2491void clang::sema::AnalysisBasedWarnings::IssueWarnings(
2492 TranslationUnitDecl *TU) {
2493 if (!TU)
2494 return; // This is unexpected, give up quietly.
2495
2496 DiagnosticsEngine &Diags = S.getDiagnostics();
2497
2498 if (S.hasUncompilableErrorOccurred() || Diags.getIgnoreAllWarnings())
2499 // exit if having uncompilable errors or ignoring all warnings:
2500 return;
2501
2502 DiagnosticOptions &DiagOpts = Diags.getDiagnosticOptions();
2503
2504 // UnsafeBufferUsage analysis settings.
2505 bool UnsafeBufferUsageCanEmitSuggestions = S.getLangOpts().CPlusPlus20;
2506 bool UnsafeBufferUsageShouldEmitSuggestions = // Should != Can.
2507 UnsafeBufferUsageCanEmitSuggestions &&
2508 DiagOpts.ShowSafeBufferUsageSuggestions;
2509 bool UnsafeBufferUsageShouldSuggestSuggestions =
2510 UnsafeBufferUsageCanEmitSuggestions &&
2511 !DiagOpts.ShowSafeBufferUsageSuggestions;
2512 UnsafeBufferUsageReporter R(S, UnsafeBufferUsageShouldSuggestSuggestions);
2513
2514 // The Callback function that performs analyses:
2515 auto CallAnalyzers = [&](const Decl *Node) -> void {
2516 // Perform unsafe buffer usage analysis:
2517 if (!Diags.isIgnored(diag::warn_unsafe_buffer_operation,
2518 Node->getBeginLoc()) ||
2519 !Diags.isIgnored(diag::warn_unsafe_buffer_variable,
2520 Node->getBeginLoc()) ||
2521 !Diags.isIgnored(diag::warn_unsafe_buffer_usage_in_container,
2522 Node->getBeginLoc())) {
2523 clang::checkUnsafeBufferUsage(D: Node, Handler&: R,
2524 EmitSuggestions: UnsafeBufferUsageShouldEmitSuggestions);
2525 }
2526
2527 // More analysis ...
2528 };
2529 // Emit per-function analysis-based warnings that require the whole-TU
2530 // reasoning. Check if any of them is enabled at all before scanning the AST:
2531 if (!Diags.isIgnored(diag::warn_unsafe_buffer_operation, SourceLocation()) ||
2532 !Diags.isIgnored(diag::warn_unsafe_buffer_variable, SourceLocation()) ||
2533 !Diags.isIgnored(diag::warn_unsafe_buffer_usage_in_container,
2534 SourceLocation())) {
2535 CallableVisitor(CallAnalyzers).TraverseTranslationUnitDecl(TU);
2536 }
2537}
2538
2539void clang::sema::AnalysisBasedWarnings::IssueWarnings(
2540 sema::AnalysisBasedWarnings::Policy P, sema::FunctionScopeInfo *fscope,
2541 const Decl *D, QualType BlockType) {
2542
2543 // We avoid doing analysis-based warnings when there are errors for
2544 // two reasons:
2545 // (1) The CFGs often can't be constructed (if the body is invalid), so
2546 // don't bother trying.
2547 // (2) The code already has problems; running the analysis just takes more
2548 // time.
2549 DiagnosticsEngine &Diags = S.getDiagnostics();
2550
2551 // Do not do any analysis if we are going to just ignore them.
2552 if (Diags.getIgnoreAllWarnings() ||
2553 (Diags.getSuppressSystemWarnings() &&
2554 S.SourceMgr.isInSystemHeader(Loc: D->getLocation())))
2555 return;
2556
2557 // For code in dependent contexts, we'll do this at instantiation time.
2558 if (cast<DeclContext>(Val: D)->isDependentContext())
2559 return;
2560
2561 if (S.hasUncompilableErrorOccurred()) {
2562 // Flush out any possibly unreachable diagnostics.
2563 flushDiagnostics(S, fscope);
2564 return;
2565 }
2566
2567 const Stmt *Body = D->getBody();
2568 assert(Body);
2569
2570 // Construct the analysis context with the specified CFG build options.
2571 AnalysisDeclContext AC(/* AnalysisDeclContextManager */ nullptr, D);
2572
2573 // Don't generate EH edges for CallExprs as we'd like to avoid the n^2
2574 // explosion for destructors that can result and the compile time hit.
2575 AC.getCFGBuildOptions().PruneTriviallyFalseEdges = true;
2576 AC.getCFGBuildOptions().AddEHEdges = false;
2577 AC.getCFGBuildOptions().AddInitializers = true;
2578 AC.getCFGBuildOptions().AddImplicitDtors = true;
2579 AC.getCFGBuildOptions().AddTemporaryDtors = true;
2580 AC.getCFGBuildOptions().AddCXXNewAllocator = false;
2581 AC.getCFGBuildOptions().AddCXXDefaultInitExprInCtors = true;
2582
2583 // Force that certain expressions appear as CFGElements in the CFG. This
2584 // is used to speed up various analyses.
2585 // FIXME: This isn't the right factoring. This is here for initial
2586 // prototyping, but we need a way for analyses to say what expressions they
2587 // expect to always be CFGElements and then fill in the BuildOptions
2588 // appropriately. This is essentially a layering violation.
2589 if (P.enableCheckUnreachable || P.enableThreadSafetyAnalysis ||
2590 P.enableConsumedAnalysis) {
2591 // Unreachable code analysis and thread safety require a linearized CFG.
2592 AC.getCFGBuildOptions().setAllAlwaysAdd();
2593 }
2594 else {
2595 AC.getCFGBuildOptions()
2596 .setAlwaysAdd(Stmt::BinaryOperatorClass)
2597 .setAlwaysAdd(Stmt::CompoundAssignOperatorClass)
2598 .setAlwaysAdd(Stmt::BlockExprClass)
2599 .setAlwaysAdd(Stmt::CStyleCastExprClass)
2600 .setAlwaysAdd(Stmt::DeclRefExprClass)
2601 .setAlwaysAdd(Stmt::ImplicitCastExprClass)
2602 .setAlwaysAdd(Stmt::UnaryOperatorClass);
2603 }
2604
2605 // Install the logical handler.
2606 std::optional<LogicalErrorHandler> LEH;
2607 if (LogicalErrorHandler::hasActiveDiagnostics(Diags, Loc: D->getBeginLoc())) {
2608 LEH.emplace(args&: S);
2609 AC.getCFGBuildOptions().Observer = &*LEH;
2610 }
2611
2612 // Emit delayed diagnostics.
2613 if (!fscope->PossiblyUnreachableDiags.empty()) {
2614 bool analyzed = false;
2615
2616 // Register the expressions with the CFGBuilder.
2617 for (const auto &D : fscope->PossiblyUnreachableDiags) {
2618 for (const Stmt *S : D.Stmts)
2619 AC.registerForcedBlockExpression(stmt: S);
2620 }
2621
2622 if (AC.getCFG()) {
2623 analyzed = true;
2624 for (const auto &D : fscope->PossiblyUnreachableDiags) {
2625 bool AllReachable = true;
2626 for (const Stmt *S : D.Stmts) {
2627 const CFGBlock *block = AC.getBlockForRegisteredExpression(stmt: S);
2628 CFGReverseBlockReachabilityAnalysis *cra =
2629 AC.getCFGReachablityAnalysis();
2630 // FIXME: We should be able to assert that block is non-null, but
2631 // the CFG analysis can skip potentially-evaluated expressions in
2632 // edge cases; see test/Sema/vla-2.c.
2633 if (block && cra) {
2634 // Can this block be reached from the entrance?
2635 if (!cra->isReachable(Src: &AC.getCFG()->getEntry(), Dst: block)) {
2636 AllReachable = false;
2637 break;
2638 }
2639 }
2640 // If we cannot map to a basic block, assume the statement is
2641 // reachable.
2642 }
2643
2644 if (AllReachable)
2645 S.Diag(Loc: D.Loc, PD: D.PD);
2646 }
2647 }
2648
2649 if (!analyzed)
2650 flushDiagnostics(S, fscope);
2651 }
2652
2653 // Warning: check missing 'return'
2654 if (P.enableCheckFallThrough) {
2655 const CheckFallThroughDiagnostics &CD =
2656 (isa<BlockDecl>(Val: D)
2657 ? CheckFallThroughDiagnostics::MakeForBlock()
2658 : (isa<CXXMethodDecl>(Val: D) &&
2659 cast<CXXMethodDecl>(Val: D)->getOverloadedOperator() == OO_Call &&
2660 cast<CXXMethodDecl>(Val: D)->getParent()->isLambda())
2661 ? CheckFallThroughDiagnostics::MakeForLambda()
2662 : (fscope->isCoroutine()
2663 ? CheckFallThroughDiagnostics::MakeForCoroutine(Func: D)
2664 : CheckFallThroughDiagnostics::MakeForFunction(Func: D)));
2665 CheckFallThroughForBody(S, D, Body, BlockType, CD, AC, FSI: fscope);
2666 }
2667
2668 // Warning: check for unreachable code
2669 if (P.enableCheckUnreachable) {
2670 // Only check for unreachable code on non-template instantiations.
2671 // Different template instantiations can effectively change the control-flow
2672 // and it is very difficult to prove that a snippet of code in a template
2673 // is unreachable for all instantiations.
2674 bool isTemplateInstantiation = false;
2675 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Val: D))
2676 isTemplateInstantiation = Function->isTemplateInstantiation();
2677 if (!isTemplateInstantiation)
2678 CheckUnreachable(S, AC);
2679 }
2680
2681 // Check for thread safety violations
2682 if (P.enableThreadSafetyAnalysis) {
2683 SourceLocation FL = AC.getDecl()->getLocation();
2684 SourceLocation FEL = AC.getDecl()->getEndLoc();
2685 threadSafety::ThreadSafetyReporter Reporter(S, FL, FEL);
2686 if (!Diags.isIgnored(diag::warn_thread_safety_beta, D->getBeginLoc()))
2687 Reporter.setIssueBetaWarnings(true);
2688 if (!Diags.isIgnored(diag::warn_thread_safety_verbose, D->getBeginLoc()))
2689 Reporter.setVerbose(true);
2690
2691 threadSafety::runThreadSafetyAnalysis(AC, Handler&: Reporter,
2692 Bset: &S.ThreadSafetyDeclCache);
2693 Reporter.emitDiagnostics();
2694 }
2695
2696 // Check for violations of consumed properties.
2697 if (P.enableConsumedAnalysis) {
2698 consumed::ConsumedWarningsHandler WarningHandler(S);
2699 consumed::ConsumedAnalyzer Analyzer(WarningHandler);
2700 Analyzer.run(AC);
2701 }
2702
2703 if (!Diags.isIgnored(diag::warn_uninit_var, D->getBeginLoc()) ||
2704 !Diags.isIgnored(diag::warn_sometimes_uninit_var, D->getBeginLoc()) ||
2705 !Diags.isIgnored(diag::warn_maybe_uninit_var, D->getBeginLoc()) ||
2706 !Diags.isIgnored(diag::warn_uninit_const_reference, D->getBeginLoc())) {
2707 if (CFG *cfg = AC.getCFG()) {
2708 UninitValsDiagReporter reporter(S);
2709 UninitVariablesAnalysisStats stats;
2710 std::memset(s: &stats, c: 0, n: sizeof(UninitVariablesAnalysisStats));
2711 runUninitializedVariablesAnalysis(dc: *cast<DeclContext>(Val: D), cfg: *cfg, ac&: AC,
2712 handler&: reporter, stats);
2713
2714 if (S.CollectStats && stats.NumVariablesAnalyzed > 0) {
2715 ++NumUninitAnalysisFunctions;
2716 NumUninitAnalysisVariables += stats.NumVariablesAnalyzed;
2717 NumUninitAnalysisBlockVisits += stats.NumBlockVisits;
2718 MaxUninitAnalysisVariablesPerFunction =
2719 std::max(a: MaxUninitAnalysisVariablesPerFunction,
2720 b: stats.NumVariablesAnalyzed);
2721 MaxUninitAnalysisBlockVisitsPerFunction =
2722 std::max(a: MaxUninitAnalysisBlockVisitsPerFunction,
2723 b: stats.NumBlockVisits);
2724 }
2725 }
2726 }
2727
2728 // Check for violations of "called once" parameter properties.
2729 if (S.getLangOpts().ObjC && !S.getLangOpts().CPlusPlus &&
2730 shouldAnalyzeCalledOnceParameters(Diags, At: D->getBeginLoc())) {
2731 if (AC.getCFG()) {
2732 CalledOnceCheckReporter Reporter(S, IPData->CalledOnceData);
2733 checkCalledOnceParameters(
2734 AC, Handler&: Reporter,
2735 CheckConventionalParameters: shouldAnalyzeCalledOnceConventions(Diags, At: D->getBeginLoc()));
2736 }
2737 }
2738
2739 bool FallThroughDiagFull =
2740 !Diags.isIgnored(diag::warn_unannotated_fallthrough, D->getBeginLoc());
2741 bool FallThroughDiagPerFunction = !Diags.isIgnored(
2742 diag::warn_unannotated_fallthrough_per_function, D->getBeginLoc());
2743 if (FallThroughDiagFull || FallThroughDiagPerFunction ||
2744 fscope->HasFallthroughStmt) {
2745 DiagnoseSwitchLabelsFallthrough(S, AC, PerFunction: !FallThroughDiagFull);
2746 }
2747
2748 if (S.getLangOpts().ObjCWeak &&
2749 !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, D->getBeginLoc()))
2750 diagnoseRepeatedUseOfWeak(S, CurFn: fscope, D, PM: AC.getParentMap());
2751
2752
2753 // Check for infinite self-recursion in functions
2754 if (!Diags.isIgnored(diag::warn_infinite_recursive_function,
2755 D->getBeginLoc())) {
2756 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Val: D)) {
2757 checkRecursiveFunction(S, FD, Body, AC);
2758 }
2759 }
2760
2761 // Check for throw out of non-throwing function.
2762 if (!Diags.isIgnored(diag::warn_throw_in_noexcept_func, D->getBeginLoc()))
2763 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Val: D))
2764 if (S.getLangOpts().CPlusPlus && !fscope->isCoroutine() && isNoexcept(FD))
2765 checkThrowInNonThrowingFunc(S, FD, AC);
2766
2767 // If none of the previous checks caused a CFG build, trigger one here
2768 // for the logical error handler.
2769 if (LogicalErrorHandler::hasActiveDiagnostics(Diags, Loc: D->getBeginLoc())) {
2770 AC.getCFG();
2771 }
2772
2773 // Collect statistics about the CFG if it was built.
2774 if (S.CollectStats && AC.isCFGBuilt()) {
2775 ++NumFunctionsAnalyzed;
2776 if (CFG *cfg = AC.getCFG()) {
2777 // If we successfully built a CFG for this context, record some more
2778 // detail information about it.
2779 NumCFGBlocks += cfg->getNumBlockIDs();
2780 MaxCFGBlocksPerFunction = std::max(a: MaxCFGBlocksPerFunction,
2781 b: cfg->getNumBlockIDs());
2782 } else {
2783 ++NumFunctionsWithBadCFGs;
2784 }
2785 }
2786}
2787
2788void clang::sema::AnalysisBasedWarnings::PrintStats() const {
2789 llvm::errs() << "\n*** Analysis Based Warnings Stats:\n";
2790
2791 unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs;
2792 unsigned AvgCFGBlocksPerFunction =
2793 !NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt;
2794 llvm::errs() << NumFunctionsAnalyzed << " functions analyzed ("
2795 << NumFunctionsWithBadCFGs << " w/o CFGs).\n"
2796 << " " << NumCFGBlocks << " CFG blocks built.\n"
2797 << " " << AvgCFGBlocksPerFunction
2798 << " average CFG blocks per function.\n"
2799 << " " << MaxCFGBlocksPerFunction
2800 << " max CFG blocks per function.\n";
2801
2802 unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0
2803 : NumUninitAnalysisVariables/NumUninitAnalysisFunctions;
2804 unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0
2805 : NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions;
2806 llvm::errs() << NumUninitAnalysisFunctions
2807 << " functions analyzed for uninitialiazed variables\n"
2808 << " " << NumUninitAnalysisVariables << " variables analyzed.\n"
2809 << " " << AvgUninitVariablesPerFunction
2810 << " average variables per function.\n"
2811 << " " << MaxUninitAnalysisVariablesPerFunction
2812 << " max variables per function.\n"
2813 << " " << NumUninitAnalysisBlockVisits << " block visits.\n"
2814 << " " << AvgUninitBlockVisitsPerFunction
2815 << " average block visits per function.\n"
2816 << " " << MaxUninitAnalysisBlockVisitsPerFunction
2817 << " max block visits per function.\n";
2818}
2819

source code of clang/lib/Sema/AnalysisBasedWarnings.cpp