1//===--- JumpDiagnostics.cpp - Protected scope jump analysis ------*- 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 implements the JumpScopeChecker class, which is used to diagnose
10// jumps that enter a protected scope in an invalid way.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/AST/DeclCXX.h"
15#include "clang/AST/Expr.h"
16#include "clang/AST/ExprCXX.h"
17#include "clang/AST/StmtCXX.h"
18#include "clang/AST/StmtObjC.h"
19#include "clang/AST/StmtOpenACC.h"
20#include "clang/AST/StmtOpenMP.h"
21#include "clang/Basic/SourceLocation.h"
22#include "clang/Sema/SemaInternal.h"
23#include "llvm/ADT/BitVector.h"
24using namespace clang;
25
26namespace {
27
28/// JumpScopeChecker - This object is used by Sema to diagnose invalid jumps
29/// into VLA and other protected scopes. For example, this rejects:
30/// goto L;
31/// int a[n];
32/// L:
33///
34/// We also detect jumps out of protected scopes when it's not possible to do
35/// cleanups properly. Indirect jumps and ASM jumps can't do cleanups because
36/// the target is unknown. Return statements with \c [[clang::musttail]] cannot
37/// handle any cleanups due to the nature of a tail call.
38class JumpScopeChecker {
39 Sema &S;
40
41 /// Permissive - True when recovering from errors, in which case precautions
42 /// are taken to handle incomplete scope information.
43 const bool Permissive;
44
45 /// GotoScope - This is a record that we use to keep track of all of the
46 /// scopes that are introduced by VLAs and other things that scope jumps like
47 /// gotos. This scope tree has nothing to do with the source scope tree,
48 /// because you can have multiple VLA scopes per compound statement, and most
49 /// compound statements don't introduce any scopes.
50 struct GotoScope {
51 /// ParentScope - The index in ScopeMap of the parent scope. This is 0 for
52 /// the parent scope is the function body.
53 unsigned ParentScope;
54
55 /// InDiag - The note to emit if there is a jump into this scope.
56 unsigned InDiag;
57
58 /// OutDiag - The note to emit if there is an indirect jump out
59 /// of this scope. Direct jumps always clean up their current scope
60 /// in an orderly way.
61 unsigned OutDiag;
62
63 /// Loc - Location to emit the diagnostic.
64 SourceLocation Loc;
65
66 GotoScope(unsigned parentScope, unsigned InDiag, unsigned OutDiag,
67 SourceLocation L)
68 : ParentScope(parentScope), InDiag(InDiag), OutDiag(OutDiag), Loc(L) {}
69 };
70
71 SmallVector<GotoScope, 48> Scopes;
72 llvm::DenseMap<Stmt*, unsigned> LabelAndGotoScopes;
73 SmallVector<Stmt*, 16> Jumps;
74
75 SmallVector<Stmt*, 4> IndirectJumps;
76 SmallVector<LabelDecl *, 4> IndirectJumpTargets;
77 SmallVector<AttributedStmt *, 4> MustTailStmts;
78
79public:
80 JumpScopeChecker(Stmt *Body, Sema &S);
81private:
82 void BuildScopeInformation(Decl *D, unsigned &ParentScope);
83 void BuildScopeInformation(VarDecl *D, const BlockDecl *BDecl,
84 unsigned &ParentScope);
85 void BuildScopeInformation(CompoundLiteralExpr *CLE, unsigned &ParentScope);
86 void BuildScopeInformation(Stmt *S, unsigned &origParentScope);
87
88 void VerifyJumps();
89 void VerifyIndirectJumps();
90 void VerifyMustTailStmts();
91 void NoteJumpIntoScopes(ArrayRef<unsigned> ToScopes);
92 void DiagnoseIndirectOrAsmJump(Stmt *IG, unsigned IGScope, LabelDecl *Target,
93 unsigned TargetScope);
94 void CheckJump(Stmt *From, Stmt *To, SourceLocation DiagLoc,
95 unsigned JumpDiag, unsigned JumpDiagWarning,
96 unsigned JumpDiagCompat);
97 void CheckGotoStmt(GotoStmt *GS);
98 const Attr *GetMustTailAttr(AttributedStmt *AS);
99
100 unsigned GetDeepestCommonScope(unsigned A, unsigned B);
101};
102} // end anonymous namespace
103
104#define CHECK_PERMISSIVE(x) (assert(Permissive || !(x)), (Permissive && (x)))
105
106JumpScopeChecker::JumpScopeChecker(Stmt *Body, Sema &s)
107 : S(s), Permissive(s.hasAnyUnrecoverableErrorsInThisFunction()) {
108 // Add a scope entry for function scope.
109 Scopes.push_back(Elt: GotoScope(~0U, ~0U, ~0U, SourceLocation()));
110
111 // Build information for the top level compound statement, so that we have a
112 // defined scope record for every "goto" and label.
113 unsigned BodyParentScope = 0;
114 BuildScopeInformation(S: Body, origParentScope&: BodyParentScope);
115
116 // Check that all jumps we saw are kosher.
117 VerifyJumps();
118 VerifyIndirectJumps();
119 VerifyMustTailStmts();
120}
121
122/// GetDeepestCommonScope - Finds the innermost scope enclosing the
123/// two scopes.
124unsigned JumpScopeChecker::GetDeepestCommonScope(unsigned A, unsigned B) {
125 while (A != B) {
126 // Inner scopes are created after outer scopes and therefore have
127 // higher indices.
128 if (A < B) {
129 assert(Scopes[B].ParentScope < B);
130 B = Scopes[B].ParentScope;
131 } else {
132 assert(Scopes[A].ParentScope < A);
133 A = Scopes[A].ParentScope;
134 }
135 }
136 return A;
137}
138
139typedef std::pair<unsigned,unsigned> ScopePair;
140
141/// GetDiagForGotoScopeDecl - If this decl induces a new goto scope, return a
142/// diagnostic that should be emitted if control goes over it. If not, return 0.
143static ScopePair GetDiagForGotoScopeDecl(Sema &S, const Decl *D) {
144 if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D)) {
145 unsigned InDiag = 0;
146 unsigned OutDiag = 0;
147
148 if (VD->getType()->isVariablyModifiedType())
149 InDiag = diag::note_protected_by_vla;
150
151 if (VD->hasAttr<BlocksAttr>())
152 return ScopePair(diag::note_protected_by___block,
153 diag::note_exits___block);
154
155 if (VD->hasAttr<CleanupAttr>())
156 return ScopePair(diag::note_protected_by_cleanup,
157 diag::note_exits_cleanup);
158
159 if (VD->hasLocalStorage()) {
160 switch (VD->getType().isDestructedType()) {
161 case QualType::DK_objc_strong_lifetime:
162 return ScopePair(diag::note_protected_by_objc_strong_init,
163 diag::note_exits_objc_strong);
164
165 case QualType::DK_objc_weak_lifetime:
166 return ScopePair(diag::note_protected_by_objc_weak_init,
167 diag::note_exits_objc_weak);
168
169 case QualType::DK_nontrivial_c_struct:
170 return ScopePair(diag::note_protected_by_non_trivial_c_struct_init,
171 diag::note_exits_dtor);
172
173 case QualType::DK_cxx_destructor:
174 OutDiag = diag::note_exits_dtor;
175 break;
176
177 case QualType::DK_none:
178 break;
179 }
180 }
181
182 // An earlier diag::note_protected_by_vla is more severe, so don't overwrite
183 // it here.
184 if (const Expr *Init = VD->getInit();
185 !InDiag && VD->hasLocalStorage() && Init && !Init->containsErrors()) {
186 // C++11 [stmt.dcl]p3:
187 // A program that jumps from a point where a variable with automatic
188 // storage duration is not in scope to a point where it is in scope
189 // is ill-formed unless the variable has scalar type, class type with
190 // a trivial default constructor and a trivial destructor, a
191 // cv-qualified version of one of these types, or an array of one of
192 // the preceding types and is declared without an initializer.
193
194 // C++03 [stmt.dcl.p3:
195 // A program that jumps from a point where a local variable
196 // with automatic storage duration is not in scope to a point
197 // where it is in scope is ill-formed unless the variable has
198 // POD type and is declared without an initializer.
199
200 InDiag = diag::note_protected_by_variable_init;
201
202 // For a variable of (array of) class type declared without an
203 // initializer, we will have call-style initialization and the initializer
204 // will be the CXXConstructExpr with no intervening nodes.
205 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Val: Init)) {
206 const CXXConstructorDecl *Ctor = CCE->getConstructor();
207 if (Ctor->isTrivial() && Ctor->isDefaultConstructor() &&
208 VD->getInitStyle() == VarDecl::CallInit) {
209 if (OutDiag)
210 InDiag = diag::note_protected_by_variable_nontriv_destructor;
211 else if (!Ctor->getParent()->isPOD())
212 InDiag = diag::note_protected_by_variable_non_pod;
213 else
214 InDiag = 0;
215 }
216 }
217 }
218
219 return ScopePair(InDiag, OutDiag);
220 }
221
222 if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(Val: D)) {
223 if (TD->getUnderlyingType()->isVariablyModifiedType())
224 return ScopePair(isa<TypedefDecl>(Val: TD)
225 ? diag::note_protected_by_vla_typedef
226 : diag::note_protected_by_vla_type_alias,
227 0);
228 }
229
230 return ScopePair(0U, 0U);
231}
232
233/// Build scope information for a declaration that is part of a DeclStmt.
234void JumpScopeChecker::BuildScopeInformation(Decl *D, unsigned &ParentScope) {
235 // If this decl causes a new scope, push and switch to it.
236 std::pair<unsigned,unsigned> Diags = GetDiagForGotoScopeDecl(S, D);
237 if (Diags.first || Diags.second) {
238 Scopes.push_back(Elt: GotoScope(ParentScope, Diags.first, Diags.second,
239 D->getLocation()));
240 ParentScope = Scopes.size()-1;
241 }
242
243 // If the decl has an initializer, walk it with the potentially new
244 // scope we just installed.
245 if (VarDecl *VD = dyn_cast<VarDecl>(Val: D))
246 if (Expr *Init = VD->getInit())
247 BuildScopeInformation(S: Init, origParentScope&: ParentScope);
248}
249
250/// Build scope information for a captured block literal variables.
251void JumpScopeChecker::BuildScopeInformation(VarDecl *D,
252 const BlockDecl *BDecl,
253 unsigned &ParentScope) {
254 // exclude captured __block variables; there's no destructor
255 // associated with the block literal for them.
256 if (D->hasAttr<BlocksAttr>())
257 return;
258 QualType T = D->getType();
259 QualType::DestructionKind destructKind = T.isDestructedType();
260 if (destructKind != QualType::DK_none) {
261 std::pair<unsigned,unsigned> Diags;
262 switch (destructKind) {
263 case QualType::DK_cxx_destructor:
264 Diags = ScopePair(diag::note_enters_block_captures_cxx_obj,
265 diag::note_exits_block_captures_cxx_obj);
266 break;
267 case QualType::DK_objc_strong_lifetime:
268 Diags = ScopePair(diag::note_enters_block_captures_strong,
269 diag::note_exits_block_captures_strong);
270 break;
271 case QualType::DK_objc_weak_lifetime:
272 Diags = ScopePair(diag::note_enters_block_captures_weak,
273 diag::note_exits_block_captures_weak);
274 break;
275 case QualType::DK_nontrivial_c_struct:
276 Diags = ScopePair(diag::note_enters_block_captures_non_trivial_c_struct,
277 diag::note_exits_block_captures_non_trivial_c_struct);
278 break;
279 case QualType::DK_none:
280 llvm_unreachable("non-lifetime captured variable");
281 }
282 SourceLocation Loc = D->getLocation();
283 if (Loc.isInvalid())
284 Loc = BDecl->getLocation();
285 Scopes.push_back(Elt: GotoScope(ParentScope,
286 Diags.first, Diags.second, Loc));
287 ParentScope = Scopes.size()-1;
288 }
289}
290
291/// Build scope information for compound literals of C struct types that are
292/// non-trivial to destruct.
293void JumpScopeChecker::BuildScopeInformation(CompoundLiteralExpr *CLE,
294 unsigned &ParentScope) {
295 unsigned InDiag = diag::note_enters_compound_literal_scope;
296 unsigned OutDiag = diag::note_exits_compound_literal_scope;
297 Scopes.push_back(Elt: GotoScope(ParentScope, InDiag, OutDiag, CLE->getExprLoc()));
298 ParentScope = Scopes.size() - 1;
299}
300
301/// BuildScopeInformation - The statements from CI to CE are known to form a
302/// coherent VLA scope with a specified parent node. Walk through the
303/// statements, adding any labels or gotos to LabelAndGotoScopes and recursively
304/// walking the AST as needed.
305void JumpScopeChecker::BuildScopeInformation(Stmt *S,
306 unsigned &origParentScope) {
307 // If this is a statement, rather than an expression, scopes within it don't
308 // propagate out into the enclosing scope. Otherwise we have to worry
309 // about block literals, which have the lifetime of their enclosing statement.
310 unsigned independentParentScope = origParentScope;
311 unsigned &ParentScope = ((isa<Expr>(Val: S) && !isa<StmtExpr>(Val: S))
312 ? origParentScope : independentParentScope);
313
314 unsigned StmtsToSkip = 0u;
315
316 // If we found a label, remember that it is in ParentScope scope.
317 switch (S->getStmtClass()) {
318 case Stmt::AddrLabelExprClass:
319 IndirectJumpTargets.push_back(Elt: cast<AddrLabelExpr>(Val: S)->getLabel());
320 break;
321
322 case Stmt::ObjCForCollectionStmtClass: {
323 auto *CS = cast<ObjCForCollectionStmt>(Val: S);
324 unsigned Diag = diag::note_protected_by_objc_fast_enumeration;
325 unsigned NewParentScope = Scopes.size();
326 Scopes.push_back(Elt: GotoScope(ParentScope, Diag, 0, S->getBeginLoc()));
327 BuildScopeInformation(S: CS->getBody(), origParentScope&: NewParentScope);
328 return;
329 }
330
331 case Stmt::IndirectGotoStmtClass:
332 // "goto *&&lbl;" is a special case which we treat as equivalent
333 // to a normal goto. In addition, we don't calculate scope in the
334 // operand (to avoid recording the address-of-label use), which
335 // works only because of the restricted set of expressions which
336 // we detect as constant targets.
337 if (cast<IndirectGotoStmt>(Val: S)->getConstantTarget())
338 goto RecordJumpScope;
339
340 LabelAndGotoScopes[S] = ParentScope;
341 IndirectJumps.push_back(Elt: S);
342 break;
343
344 case Stmt::SwitchStmtClass:
345 // Evaluate the C++17 init stmt and condition variable
346 // before entering the scope of the switch statement.
347 if (Stmt *Init = cast<SwitchStmt>(Val: S)->getInit()) {
348 BuildScopeInformation(S: Init, origParentScope&: ParentScope);
349 ++StmtsToSkip;
350 }
351 if (VarDecl *Var = cast<SwitchStmt>(Val: S)->getConditionVariable()) {
352 BuildScopeInformation(D: Var, ParentScope);
353 ++StmtsToSkip;
354 }
355 goto RecordJumpScope;
356
357 case Stmt::GCCAsmStmtClass:
358 if (!cast<GCCAsmStmt>(Val: S)->isAsmGoto())
359 break;
360 [[fallthrough]];
361
362 case Stmt::GotoStmtClass:
363 RecordJumpScope:
364 // Remember both what scope a goto is in as well as the fact that we have
365 // it. This makes the second scan not have to walk the AST again.
366 LabelAndGotoScopes[S] = ParentScope;
367 Jumps.push_back(Elt: S);
368 break;
369
370 case Stmt::IfStmtClass: {
371 IfStmt *IS = cast<IfStmt>(Val: S);
372 if (!(IS->isConstexpr() || IS->isConsteval() ||
373 IS->isObjCAvailabilityCheck()))
374 break;
375
376 unsigned Diag = diag::note_protected_by_if_available;
377 if (IS->isConstexpr())
378 Diag = diag::note_protected_by_constexpr_if;
379 else if (IS->isConsteval())
380 Diag = diag::note_protected_by_consteval_if;
381
382 if (VarDecl *Var = IS->getConditionVariable())
383 BuildScopeInformation(D: Var, ParentScope);
384
385 // Cannot jump into the middle of the condition.
386 unsigned NewParentScope = Scopes.size();
387 Scopes.push_back(Elt: GotoScope(ParentScope, Diag, 0, IS->getBeginLoc()));
388
389 if (!IS->isConsteval())
390 BuildScopeInformation(S: IS->getCond(), origParentScope&: NewParentScope);
391
392 // Jumps into either arm of an 'if constexpr' are not allowed.
393 NewParentScope = Scopes.size();
394 Scopes.push_back(Elt: GotoScope(ParentScope, Diag, 0, IS->getBeginLoc()));
395 BuildScopeInformation(S: IS->getThen(), origParentScope&: NewParentScope);
396 if (Stmt *Else = IS->getElse()) {
397 NewParentScope = Scopes.size();
398 Scopes.push_back(Elt: GotoScope(ParentScope, Diag, 0, IS->getBeginLoc()));
399 BuildScopeInformation(S: Else, origParentScope&: NewParentScope);
400 }
401 return;
402 }
403
404 case Stmt::CXXTryStmtClass: {
405 CXXTryStmt *TS = cast<CXXTryStmt>(Val: S);
406 {
407 unsigned NewParentScope = Scopes.size();
408 Scopes.push_back(Elt: GotoScope(ParentScope,
409 diag::note_protected_by_cxx_try,
410 diag::note_exits_cxx_try,
411 TS->getSourceRange().getBegin()));
412 if (Stmt *TryBlock = TS->getTryBlock())
413 BuildScopeInformation(S: TryBlock, origParentScope&: NewParentScope);
414 }
415
416 // Jump from the catch into the try is not allowed either.
417 for (unsigned I = 0, E = TS->getNumHandlers(); I != E; ++I) {
418 CXXCatchStmt *CS = TS->getHandler(i: I);
419 unsigned NewParentScope = Scopes.size();
420 Scopes.push_back(Elt: GotoScope(ParentScope,
421 diag::note_protected_by_cxx_catch,
422 diag::note_exits_cxx_catch,
423 CS->getSourceRange().getBegin()));
424 BuildScopeInformation(S: CS->getHandlerBlock(), origParentScope&: NewParentScope);
425 }
426 return;
427 }
428
429 case Stmt::SEHTryStmtClass: {
430 SEHTryStmt *TS = cast<SEHTryStmt>(Val: S);
431 {
432 unsigned NewParentScope = Scopes.size();
433 Scopes.push_back(Elt: GotoScope(ParentScope,
434 diag::note_protected_by_seh_try,
435 diag::note_exits_seh_try,
436 TS->getSourceRange().getBegin()));
437 if (Stmt *TryBlock = TS->getTryBlock())
438 BuildScopeInformation(S: TryBlock, origParentScope&: NewParentScope);
439 }
440
441 // Jump from __except or __finally into the __try are not allowed either.
442 if (SEHExceptStmt *Except = TS->getExceptHandler()) {
443 unsigned NewParentScope = Scopes.size();
444 Scopes.push_back(Elt: GotoScope(ParentScope,
445 diag::note_protected_by_seh_except,
446 diag::note_exits_seh_except,
447 Except->getSourceRange().getBegin()));
448 BuildScopeInformation(S: Except->getBlock(), origParentScope&: NewParentScope);
449 } else if (SEHFinallyStmt *Finally = TS->getFinallyHandler()) {
450 unsigned NewParentScope = Scopes.size();
451 Scopes.push_back(Elt: GotoScope(ParentScope,
452 diag::note_protected_by_seh_finally,
453 diag::note_exits_seh_finally,
454 Finally->getSourceRange().getBegin()));
455 BuildScopeInformation(S: Finally->getBlock(), origParentScope&: NewParentScope);
456 }
457
458 return;
459 }
460
461 case Stmt::DeclStmtClass: {
462 // If this is a declstmt with a VLA definition, it defines a scope from here
463 // to the end of the containing context.
464 DeclStmt *DS = cast<DeclStmt>(Val: S);
465 // The decl statement creates a scope if any of the decls in it are VLAs
466 // or have the cleanup attribute.
467 for (auto *I : DS->decls())
468 BuildScopeInformation(D: I, ParentScope&: origParentScope);
469 return;
470 }
471
472 case Stmt::StmtExprClass: {
473 // [GNU]
474 // Jumping into a statement expression with goto or using
475 // a switch statement outside the statement expression with
476 // a case or default label inside the statement expression is not permitted.
477 // Jumping out of a statement expression is permitted.
478 StmtExpr *SE = cast<StmtExpr>(Val: S);
479 unsigned NewParentScope = Scopes.size();
480 Scopes.push_back(Elt: GotoScope(ParentScope,
481 diag::note_enters_statement_expression,
482 /*OutDiag=*/0, SE->getBeginLoc()));
483 BuildScopeInformation(S: SE->getSubStmt(), origParentScope&: NewParentScope);
484 return;
485 }
486
487 case Stmt::ObjCAtTryStmtClass: {
488 // Disallow jumps into any part of an @try statement by pushing a scope and
489 // walking all sub-stmts in that scope.
490 ObjCAtTryStmt *AT = cast<ObjCAtTryStmt>(Val: S);
491 // Recursively walk the AST for the @try part.
492 {
493 unsigned NewParentScope = Scopes.size();
494 Scopes.push_back(Elt: GotoScope(ParentScope,
495 diag::note_protected_by_objc_try,
496 diag::note_exits_objc_try,
497 AT->getAtTryLoc()));
498 if (Stmt *TryPart = AT->getTryBody())
499 BuildScopeInformation(S: TryPart, origParentScope&: NewParentScope);
500 }
501
502 // Jump from the catch to the finally or try is not valid.
503 for (ObjCAtCatchStmt *AC : AT->catch_stmts()) {
504 unsigned NewParentScope = Scopes.size();
505 Scopes.push_back(Elt: GotoScope(ParentScope,
506 diag::note_protected_by_objc_catch,
507 diag::note_exits_objc_catch,
508 AC->getAtCatchLoc()));
509 // @catches are nested and it isn't
510 BuildScopeInformation(S: AC->getCatchBody(), origParentScope&: NewParentScope);
511 }
512
513 // Jump from the finally to the try or catch is not valid.
514 if (ObjCAtFinallyStmt *AF = AT->getFinallyStmt()) {
515 unsigned NewParentScope = Scopes.size();
516 Scopes.push_back(Elt: GotoScope(ParentScope,
517 diag::note_protected_by_objc_finally,
518 diag::note_exits_objc_finally,
519 AF->getAtFinallyLoc()));
520 BuildScopeInformation(S: AF, origParentScope&: NewParentScope);
521 }
522
523 return;
524 }
525
526 case Stmt::ObjCAtSynchronizedStmtClass: {
527 // Disallow jumps into the protected statement of an @synchronized, but
528 // allow jumps into the object expression it protects.
529 ObjCAtSynchronizedStmt *AS = cast<ObjCAtSynchronizedStmt>(Val: S);
530 // Recursively walk the AST for the @synchronized object expr, it is
531 // evaluated in the normal scope.
532 BuildScopeInformation(S: AS->getSynchExpr(), origParentScope&: ParentScope);
533
534 // Recursively walk the AST for the @synchronized part, protected by a new
535 // scope.
536 unsigned NewParentScope = Scopes.size();
537 Scopes.push_back(Elt: GotoScope(ParentScope,
538 diag::note_protected_by_objc_synchronized,
539 diag::note_exits_objc_synchronized,
540 AS->getAtSynchronizedLoc()));
541 BuildScopeInformation(S: AS->getSynchBody(), origParentScope&: NewParentScope);
542 return;
543 }
544
545 case Stmt::ObjCAutoreleasePoolStmtClass: {
546 // Disallow jumps into the protected statement of an @autoreleasepool.
547 ObjCAutoreleasePoolStmt *AS = cast<ObjCAutoreleasePoolStmt>(Val: S);
548 // Recursively walk the AST for the @autoreleasepool part, protected by a
549 // new scope.
550 unsigned NewParentScope = Scopes.size();
551 Scopes.push_back(Elt: GotoScope(ParentScope,
552 diag::note_protected_by_objc_autoreleasepool,
553 diag::note_exits_objc_autoreleasepool,
554 AS->getAtLoc()));
555 BuildScopeInformation(S: AS->getSubStmt(), origParentScope&: NewParentScope);
556 return;
557 }
558
559 case Stmt::ExprWithCleanupsClass: {
560 // Disallow jumps past full-expressions that use blocks with
561 // non-trivial cleanups of their captures. This is theoretically
562 // implementable but a lot of work which we haven't felt up to doing.
563 ExprWithCleanups *EWC = cast<ExprWithCleanups>(Val: S);
564 for (unsigned i = 0, e = EWC->getNumObjects(); i != e; ++i) {
565 if (auto *BDecl = dyn_cast<BlockDecl *>(Val: EWC->getObject(i)))
566 for (const auto &CI : BDecl->captures()) {
567 VarDecl *variable = CI.getVariable();
568 BuildScopeInformation(D: variable, BDecl, ParentScope&: origParentScope);
569 }
570 else if (auto *CLE = dyn_cast<CompoundLiteralExpr *>(Val: EWC->getObject(i)))
571 BuildScopeInformation(CLE, ParentScope&: origParentScope);
572 else
573 llvm_unreachable("unexpected cleanup object type");
574 }
575 break;
576 }
577
578 case Stmt::MaterializeTemporaryExprClass: {
579 // Disallow jumps out of scopes containing temporaries lifetime-extended to
580 // automatic storage duration.
581 MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(Val: S);
582 if (MTE->getStorageDuration() == SD_Automatic) {
583 const Expr *ExtendedObject =
584 MTE->getSubExpr()->skipRValueSubobjectAdjustments();
585 if (ExtendedObject->getType().isDestructedType()) {
586 Scopes.push_back(Elt: GotoScope(ParentScope, 0,
587 diag::note_exits_temporary_dtor,
588 ExtendedObject->getExprLoc()));
589 origParentScope = Scopes.size()-1;
590 }
591 }
592 break;
593 }
594
595 case Stmt::DeferStmtClass: {
596 auto *D = cast<DeferStmt>(Val: S);
597
598 {
599 // Disallow jumps over defer statements.
600 unsigned NewParentScope = Scopes.size();
601 Scopes.emplace_back(Args&: ParentScope, Args: diag::note_protected_by_defer_stmt, Args: 0,
602 Args: D->getDeferLoc());
603 origParentScope = NewParentScope;
604 }
605
606 // Disallow jumps into or out of defer statements.
607 {
608 unsigned NewParentScope = Scopes.size();
609 Scopes.emplace_back(Args&: ParentScope, Args: diag::note_enters_defer_stmt,
610 Args: diag::note_exits_defer_stmt, Args: D->getDeferLoc());
611 BuildScopeInformation(S: D->getBody(), origParentScope&: NewParentScope);
612 }
613 return;
614 }
615
616 case Stmt::CaseStmtClass:
617 case Stmt::DefaultStmtClass:
618 case Stmt::LabelStmtClass:
619 LabelAndGotoScopes[S] = ParentScope;
620 break;
621
622 case Stmt::OpenACCComputeConstructClass: {
623 unsigned NewParentScope = Scopes.size();
624 OpenACCComputeConstruct *CC = cast<OpenACCComputeConstruct>(Val: S);
625 Scopes.push_back(Elt: GotoScope(
626 ParentScope, diag::note_acc_branch_into_compute_construct,
627 diag::note_acc_branch_out_of_compute_construct, CC->getBeginLoc()));
628 // This can be 'null' if the 'body' is a break that we diagnosed, so no
629 // reason to put the scope into place.
630 if (CC->getStructuredBlock())
631 BuildScopeInformation(S: CC->getStructuredBlock(), origParentScope&: NewParentScope);
632 return;
633 }
634
635 case Stmt::OpenACCCombinedConstructClass: {
636 unsigned NewParentScope = Scopes.size();
637 OpenACCCombinedConstruct *CC = cast<OpenACCCombinedConstruct>(Val: S);
638 Scopes.push_back(Elt: GotoScope(
639 ParentScope, diag::note_acc_branch_into_compute_construct,
640 diag::note_acc_branch_out_of_compute_construct, CC->getBeginLoc()));
641 // This can be 'null' if the 'body' is a break that we diagnosed, so no
642 // reason to put the scope into place.
643 if (CC->getLoop())
644 BuildScopeInformation(S: CC->getLoop(), origParentScope&: NewParentScope);
645 return;
646 }
647
648 default:
649 if (auto *ED = dyn_cast<OMPExecutableDirective>(Val: S)) {
650 if (!ED->isStandaloneDirective()) {
651 unsigned NewParentScope = Scopes.size();
652 Scopes.emplace_back(Args&: ParentScope,
653 Args: diag::note_omp_protected_structured_block,
654 Args: diag::note_omp_exits_structured_block,
655 Args: ED->getStructuredBlock()->getBeginLoc());
656 BuildScopeInformation(S: ED->getStructuredBlock(), origParentScope&: NewParentScope);
657 return;
658 }
659 }
660 break;
661 }
662
663 for (Stmt *SubStmt : S->children()) {
664 if (!SubStmt)
665 continue;
666 if (StmtsToSkip) {
667 --StmtsToSkip;
668 continue;
669 }
670
671 // Cases, labels, attributes, and defaults aren't "scope parents". It's also
672 // important to handle these iteratively instead of recursively in
673 // order to avoid blowing out the stack.
674 while (true) {
675 Stmt *Next;
676 if (SwitchCase *SC = dyn_cast<SwitchCase>(Val: SubStmt))
677 Next = SC->getSubStmt();
678 else if (LabelStmt *LS = dyn_cast<LabelStmt>(Val: SubStmt))
679 Next = LS->getSubStmt();
680 else if (AttributedStmt *AS = dyn_cast<AttributedStmt>(Val: SubStmt)) {
681 if (GetMustTailAttr(AS)) {
682 LabelAndGotoScopes[AS] = ParentScope;
683 MustTailStmts.push_back(Elt: AS);
684 }
685 Next = AS->getSubStmt();
686 } else
687 break;
688
689 LabelAndGotoScopes[SubStmt] = ParentScope;
690 SubStmt = Next;
691 }
692
693 // Recursively walk the AST.
694 BuildScopeInformation(S: SubStmt, origParentScope&: ParentScope);
695 }
696}
697
698/// VerifyJumps - Verify each element of the Jumps array to see if they are
699/// valid, emitting diagnostics if not.
700void JumpScopeChecker::VerifyJumps() {
701 while (!Jumps.empty()) {
702 Stmt *Jump = Jumps.pop_back_val();
703
704 // With a goto,
705 if (GotoStmt *GS = dyn_cast<GotoStmt>(Val: Jump)) {
706 // The label may not have a statement if it's coming from inline MS ASM.
707 if (GS->getLabel()->getStmt()) {
708 CheckJump(From: GS, To: GS->getLabel()->getStmt(), DiagLoc: GS->getGotoLoc(),
709 JumpDiag: diag::err_goto_into_protected_scope,
710 JumpDiagWarning: diag::ext_goto_into_protected_scope,
711 JumpDiagCompat: S.getLangOpts().CPlusPlus
712 ? diag::warn_cxx98_compat_goto_into_protected_scope
713 : diag::warn_cpp_compat_goto_into_protected_scope);
714 }
715 CheckGotoStmt(GS);
716 continue;
717 }
718
719 // If an asm goto jumps to a different scope, things like destructors or
720 // initializers might not be run which may be suprising to users. Perhaps
721 // this behavior can be changed in the future, but today Clang will not
722 // generate such code. Produce a diagnostic instead. See also the
723 // discussion here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110728.
724 if (auto *G = dyn_cast<GCCAsmStmt>(Val: Jump)) {
725 for (AddrLabelExpr *L : G->labels()) {
726 LabelDecl *LD = L->getLabel();
727 unsigned JumpScope = LabelAndGotoScopes[G];
728 unsigned TargetScope = LabelAndGotoScopes[LD->getStmt()];
729 if (JumpScope != TargetScope)
730 DiagnoseIndirectOrAsmJump(IG: G, IGScope: JumpScope, Target: LD, TargetScope);
731 }
732 continue;
733 }
734
735 // We only get indirect gotos here when they have a constant target.
736 if (IndirectGotoStmt *IGS = dyn_cast<IndirectGotoStmt>(Val: Jump)) {
737 LabelDecl *Target = IGS->getConstantTarget();
738 CheckJump(From: IGS, To: Target->getStmt(), DiagLoc: IGS->getGotoLoc(),
739 JumpDiag: diag::err_goto_into_protected_scope,
740 JumpDiagWarning: diag::ext_goto_into_protected_scope,
741 JumpDiagCompat: S.getLangOpts().CPlusPlus
742 ? diag::warn_cxx98_compat_goto_into_protected_scope
743 : diag::warn_cpp_compat_goto_into_protected_scope);
744 continue;
745 }
746
747 SwitchStmt *SS = cast<SwitchStmt>(Val: Jump);
748 for (SwitchCase *SC = SS->getSwitchCaseList(); SC;
749 SC = SC->getNextSwitchCase()) {
750 if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(SC)))
751 continue;
752 SourceLocation Loc;
753 if (CaseStmt *CS = dyn_cast<CaseStmt>(Val: SC))
754 Loc = CS->getBeginLoc();
755 else if (DefaultStmt *DS = dyn_cast<DefaultStmt>(Val: SC))
756 Loc = DS->getBeginLoc();
757 else
758 Loc = SC->getBeginLoc();
759 CheckJump(From: SS, To: SC, DiagLoc: Loc, JumpDiag: diag::err_switch_into_protected_scope, JumpDiagWarning: 0,
760 JumpDiagCompat: S.getLangOpts().CPlusPlus
761 ? diag::warn_cxx98_compat_switch_into_protected_scope
762 : diag::warn_cpp_compat_switch_into_protected_scope);
763 }
764 }
765}
766
767/// VerifyIndirectJumps - Verify whether any possible indirect goto jump might
768/// cross a protection boundary. Unlike direct jumps, indirect goto jumps
769/// count cleanups as protection boundaries: since there's no way to know where
770/// the jump is going, we can't implicitly run the right cleanups the way we
771/// can with direct jumps. Thus, an indirect/asm jump is "trivial" if it
772/// bypasses no initializations and no teardowns. More formally, an
773/// indirect/asm jump from A to B is trivial if the path out from A to DCA(A,B)
774/// is trivial and the path in from DCA(A,B) to B is trivial, where DCA(A,B) is
775/// the deepest common ancestor of A and B. Jump-triviality is transitive but
776/// asymmetric.
777///
778/// A path in is trivial if none of the entered scopes have an InDiag.
779/// A path out is trivial is none of the exited scopes have an OutDiag.
780///
781/// Under these definitions, this function checks that the indirect
782/// jump between A and B is trivial for every indirect goto statement A
783/// and every label B whose address was taken in the function.
784void JumpScopeChecker::VerifyIndirectJumps() {
785 if (IndirectJumps.empty())
786 return;
787 // If there aren't any address-of-label expressions in this function,
788 // complain about the first indirect goto.
789 if (IndirectJumpTargets.empty()) {
790 S.Diag(Loc: IndirectJumps[0]->getBeginLoc(),
791 DiagID: diag::err_indirect_goto_without_addrlabel);
792 return;
793 }
794 // Collect a single representative of every scope containing an indirect
795 // goto. For most code bases, this substantially cuts down on the number of
796 // jump sites we'll have to consider later.
797 using JumpScope = std::pair<unsigned, Stmt *>;
798 SmallVector<JumpScope, 32> JumpScopes;
799 {
800 llvm::DenseMap<unsigned, Stmt*> JumpScopesMap;
801 for (Stmt *IG : IndirectJumps) {
802 if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(IG)))
803 continue;
804 unsigned IGScope = LabelAndGotoScopes[IG];
805 JumpScopesMap.try_emplace(Key: IGScope, Args&: IG);
806 }
807 JumpScopes.reserve(N: JumpScopesMap.size());
808 for (auto &Pair : JumpScopesMap)
809 JumpScopes.emplace_back(Args&: Pair);
810 }
811
812 // Collect a single representative of every scope containing a
813 // label whose address was taken somewhere in the function.
814 // For most code bases, there will be only one such scope.
815 llvm::DenseMap<unsigned, LabelDecl*> TargetScopes;
816 for (LabelDecl *TheLabel : IndirectJumpTargets) {
817 if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(TheLabel->getStmt())))
818 continue;
819 unsigned LabelScope = LabelAndGotoScopes[TheLabel->getStmt()];
820 TargetScopes.try_emplace(Key: LabelScope, Args&: TheLabel);
821 }
822
823 // For each target scope, make sure it's trivially reachable from
824 // every scope containing a jump site.
825 //
826 // A path between scopes always consists of exitting zero or more
827 // scopes, then entering zero or more scopes. We build a set of
828 // of scopes S from which the target scope can be trivially
829 // entered, then verify that every jump scope can be trivially
830 // exitted to reach a scope in S.
831 llvm::BitVector Reachable(Scopes.size(), false);
832 for (auto [TargetScope, TargetLabel] : TargetScopes) {
833 Reachable.reset();
834
835 // Mark all the enclosing scopes from which you can safely jump
836 // into the target scope. 'Min' will end up being the index of
837 // the shallowest such scope.
838 unsigned Min = TargetScope;
839 while (true) {
840 Reachable.set(Min);
841
842 // Don't go beyond the outermost scope.
843 if (Min == 0) break;
844
845 // Stop if we can't trivially enter the current scope.
846 if (Scopes[Min].InDiag) break;
847
848 Min = Scopes[Min].ParentScope;
849 }
850
851 // Walk through all the jump sites, checking that they can trivially
852 // reach this label scope.
853 for (auto [JumpScope, JumpStmt] : JumpScopes) {
854 unsigned Scope = JumpScope;
855 // Walk out the "scope chain" for this scope, looking for a scope
856 // we've marked reachable. For well-formed code this amortizes
857 // to O(JumpScopes.size() / Scopes.size()): we only iterate
858 // when we see something unmarked, and in well-formed code we
859 // mark everything we iterate past.
860 bool IsReachable = false;
861 while (true) {
862 if (Reachable.test(Idx: Scope)) {
863 // If we find something reachable, mark all the scopes we just
864 // walked through as reachable.
865 for (unsigned S = JumpScope; S != Scope; S = Scopes[S].ParentScope)
866 Reachable.set(S);
867 IsReachable = true;
868 break;
869 }
870
871 // Don't walk out if we've reached the top-level scope or we've
872 // gotten shallower than the shallowest reachable scope.
873 if (Scope == 0 || Scope < Min) break;
874
875 // Don't walk out through an out-diagnostic.
876 if (Scopes[Scope].OutDiag) break;
877
878 Scope = Scopes[Scope].ParentScope;
879 }
880
881 // Only diagnose if we didn't find something.
882 if (IsReachable) continue;
883
884 DiagnoseIndirectOrAsmJump(IG: JumpStmt, IGScope: JumpScope, Target: TargetLabel, TargetScope);
885 }
886 }
887}
888
889/// Return true if a particular error+note combination must be downgraded to a
890/// warning in Microsoft mode.
891static bool IsMicrosoftJumpWarning(unsigned JumpDiag, unsigned InDiagNote) {
892 return (JumpDiag == diag::err_goto_into_protected_scope &&
893 (InDiagNote == diag::note_protected_by_variable_init ||
894 InDiagNote == diag::note_protected_by_variable_nontriv_destructor));
895}
896
897/// Return true if a particular note should be downgraded to a compatibility
898/// warning in C++11 mode.
899static bool IsCXX98CompatWarning(Sema &S, unsigned InDiagNote) {
900 return S.getLangOpts().CPlusPlus11 &&
901 InDiagNote == diag::note_protected_by_variable_non_pod;
902}
903
904/// Returns true if a particular note should be a C++ compatibility warning in
905/// C mode with -Wc++-compat.
906static bool IsCppCompatWarning(Sema &S, unsigned InDiagNote) {
907 return !S.getLangOpts().CPlusPlus &&
908 InDiagNote == diag::note_protected_by_variable_init;
909}
910
911/// Produce primary diagnostic for an indirect jump statement.
912static void DiagnoseIndirectOrAsmJumpStmt(Sema &S, Stmt *Jump,
913 LabelDecl *Target, bool &Diagnosed) {
914 if (Diagnosed)
915 return;
916 bool IsAsmGoto = isa<GCCAsmStmt>(Val: Jump);
917 S.Diag(Loc: Jump->getBeginLoc(), DiagID: diag::err_indirect_goto_in_protected_scope)
918 << IsAsmGoto;
919 S.Diag(Loc: Target->getStmt()->getIdentLoc(), DiagID: diag::note_indirect_goto_target)
920 << IsAsmGoto;
921 Diagnosed = true;
922}
923
924/// Produce note diagnostics for a jump into a protected scope.
925void JumpScopeChecker::NoteJumpIntoScopes(ArrayRef<unsigned> ToScopes) {
926 if (CHECK_PERMISSIVE(ToScopes.empty()))
927 return;
928 for (unsigned I = 0, E = ToScopes.size(); I != E; ++I)
929 if (Scopes[ToScopes[I]].InDiag)
930 S.Diag(Loc: Scopes[ToScopes[I]].Loc, DiagID: Scopes[ToScopes[I]].InDiag);
931}
932
933/// Diagnose an indirect jump which is known to cross scopes.
934void JumpScopeChecker::DiagnoseIndirectOrAsmJump(Stmt *Jump, unsigned JumpScope,
935 LabelDecl *Target,
936 unsigned TargetScope) {
937 if (CHECK_PERMISSIVE(JumpScope == TargetScope))
938 return;
939
940 unsigned Common = GetDeepestCommonScope(A: JumpScope, B: TargetScope);
941 bool Diagnosed = false;
942
943 // Walk out the scope chain until we reach the common ancestor.
944 for (unsigned I = JumpScope; I != Common; I = Scopes[I].ParentScope)
945 if (Scopes[I].OutDiag) {
946 DiagnoseIndirectOrAsmJumpStmt(S, Jump, Target, Diagnosed);
947 S.Diag(Loc: Scopes[I].Loc, DiagID: Scopes[I].OutDiag);
948 }
949
950 SmallVector<unsigned, 10> ToScopesCXX98Compat, ToScopesCppCompat;
951
952 // Now walk into the scopes containing the label whose address was taken.
953 for (unsigned I = TargetScope; I != Common; I = Scopes[I].ParentScope)
954 if (IsCXX98CompatWarning(S, InDiagNote: Scopes[I].InDiag))
955 ToScopesCXX98Compat.push_back(Elt: I);
956 else if (IsCppCompatWarning(S, InDiagNote: Scopes[I].InDiag))
957 ToScopesCppCompat.push_back(Elt: I);
958 else if (Scopes[I].InDiag) {
959 DiagnoseIndirectOrAsmJumpStmt(S, Jump, Target, Diagnosed);
960 S.Diag(Loc: Scopes[I].Loc, DiagID: Scopes[I].InDiag);
961 }
962
963 // Diagnose this jump if it would be ill-formed in C++[98].
964 if (!Diagnosed) {
965 bool IsAsmGoto = isa<GCCAsmStmt>(Val: Jump);
966 auto Diag = [&](unsigned DiagId, const SmallVectorImpl<unsigned> &Notes) {
967 S.Diag(Loc: Jump->getBeginLoc(), DiagID: DiagId) << IsAsmGoto;
968 S.Diag(Loc: Target->getStmt()->getIdentLoc(), DiagID: diag::note_indirect_goto_target)
969 << IsAsmGoto;
970 NoteJumpIntoScopes(ToScopes: Notes);
971 };
972 if (!ToScopesCXX98Compat.empty())
973 Diag(diag::warn_cxx98_compat_indirect_goto_in_protected_scope,
974 ToScopesCXX98Compat);
975 else if (!ToScopesCppCompat.empty())
976 Diag(diag::warn_cpp_compat_indirect_goto_in_protected_scope,
977 ToScopesCppCompat);
978 }
979}
980
981/// CheckJump - Validate that the specified jump statement is valid: that it is
982/// jumping within or out of its current scope, not into a deeper one.
983void JumpScopeChecker::CheckJump(Stmt *From, Stmt *To, SourceLocation DiagLoc,
984 unsigned JumpDiagError,
985 unsigned JumpDiagWarning,
986 unsigned JumpDiagCompat) {
987 if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(From)))
988 return;
989 if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(To)))
990 return;
991
992 unsigned FromScope = LabelAndGotoScopes[From];
993 unsigned ToScope = LabelAndGotoScopes[To];
994
995 // Common case: exactly the same scope, which is fine.
996 if (FromScope == ToScope) return;
997
998 // Warn on gotos out of __finally blocks and defer statements.
999 if (isa<GotoStmt>(Val: From) || isa<IndirectGotoStmt>(Val: From)) {
1000 // If FromScope > ToScope, FromScope is more nested and the jump goes to a
1001 // less nested scope. Check if it crosses a __finally along the way.
1002 for (unsigned I = FromScope; I > ToScope; I = Scopes[I].ParentScope) {
1003 if (Scopes[I].InDiag == diag::note_protected_by_seh_finally) {
1004 S.Diag(Loc: From->getBeginLoc(), DiagID: diag::warn_jump_out_of_seh_finally);
1005 break;
1006 } else if (Scopes[I].InDiag ==
1007 diag::note_omp_protected_structured_block) {
1008 S.Diag(Loc: From->getBeginLoc(), DiagID: diag::err_goto_into_protected_scope);
1009 S.Diag(Loc: To->getBeginLoc(), DiagID: diag::note_omp_exits_structured_block);
1010 break;
1011 } else if (Scopes[I].InDiag ==
1012 diag::note_acc_branch_into_compute_construct) {
1013 S.Diag(Loc: From->getBeginLoc(), DiagID: diag::err_goto_into_protected_scope);
1014 S.Diag(Loc: Scopes[I].Loc, DiagID: diag::note_acc_branch_out_of_compute_construct);
1015 return;
1016 } else if (Scopes[I].OutDiag == diag::note_exits_defer_stmt) {
1017 S.Diag(Loc: From->getBeginLoc(), DiagID: diag::err_goto_into_protected_scope);
1018 S.Diag(Loc: Scopes[I].Loc, DiagID: diag::note_exits_defer_stmt);
1019 return;
1020 }
1021 }
1022 }
1023
1024 unsigned CommonScope = GetDeepestCommonScope(A: FromScope, B: ToScope);
1025
1026 // It's okay to jump out from a nested scope.
1027 if (CommonScope == ToScope) return;
1028
1029 // Pull out (and reverse) any scopes we might need to diagnose skipping.
1030 SmallVector<unsigned, 10> ToScopesCompat;
1031 SmallVector<unsigned, 10> ToScopesError;
1032 SmallVector<unsigned, 10> ToScopesWarning;
1033 for (unsigned I = ToScope; I != CommonScope; I = Scopes[I].ParentScope) {
1034 if (S.getLangOpts().MSVCCompat && S.getLangOpts().CPlusPlus &&
1035 JumpDiagWarning != 0 &&
1036 IsMicrosoftJumpWarning(JumpDiag: JumpDiagError, InDiagNote: Scopes[I].InDiag))
1037 ToScopesWarning.push_back(Elt: I);
1038 else if (IsCXX98CompatWarning(S, InDiagNote: Scopes[I].InDiag) ||
1039 IsCppCompatWarning(S, InDiagNote: Scopes[I].InDiag))
1040 ToScopesCompat.push_back(Elt: I);
1041 else if (Scopes[I].InDiag)
1042 ToScopesError.push_back(Elt: I);
1043 }
1044
1045 // Handle warnings.
1046 if (!ToScopesWarning.empty()) {
1047 S.Diag(Loc: DiagLoc, DiagID: JumpDiagWarning);
1048 NoteJumpIntoScopes(ToScopes: ToScopesWarning);
1049 assert(isa<LabelStmt>(To));
1050 LabelStmt *Label = cast<LabelStmt>(Val: To);
1051 Label->setSideEntry(true);
1052 }
1053
1054 // Handle errors.
1055 if (!ToScopesError.empty()) {
1056 S.Diag(Loc: DiagLoc, DiagID: JumpDiagError);
1057 NoteJumpIntoScopes(ToScopes: ToScopesError);
1058 }
1059
1060 // Handle -Wc++98-compat or -Wc++-compat warnings if the jump is well-formed.
1061 if (ToScopesError.empty() && !ToScopesCompat.empty()) {
1062 S.Diag(Loc: DiagLoc, DiagID: JumpDiagCompat);
1063 NoteJumpIntoScopes(ToScopes: ToScopesCompat);
1064 }
1065}
1066
1067void JumpScopeChecker::CheckGotoStmt(GotoStmt *GS) {
1068 if (GS->getLabel()->isMSAsmLabel()) {
1069 S.Diag(Loc: GS->getGotoLoc(), DiagID: diag::err_goto_ms_asm_label)
1070 << GS->getLabel()->getIdentifier();
1071 S.Diag(Loc: GS->getLabel()->getLocation(), DiagID: diag::note_goto_ms_asm_label)
1072 << GS->getLabel()->getIdentifier();
1073 }
1074}
1075
1076void JumpScopeChecker::VerifyMustTailStmts() {
1077 for (AttributedStmt *AS : MustTailStmts) {
1078 for (unsigned I = LabelAndGotoScopes[AS]; I; I = Scopes[I].ParentScope) {
1079 if (Scopes[I].OutDiag) {
1080 S.Diag(Loc: AS->getBeginLoc(), DiagID: diag::err_musttail_scope);
1081 S.Diag(Loc: Scopes[I].Loc, DiagID: Scopes[I].OutDiag);
1082 }
1083 }
1084 }
1085}
1086
1087const Attr *JumpScopeChecker::GetMustTailAttr(AttributedStmt *AS) {
1088 ArrayRef<const Attr *> Attrs = AS->getAttrs();
1089 const auto *Iter =
1090 llvm::find_if(Range&: Attrs, P: [](const Attr *A) { return isa<MustTailAttr>(Val: A); });
1091 return Iter != Attrs.end() ? *Iter : nullptr;
1092}
1093
1094void Sema::DiagnoseInvalidJumps(Stmt *Body) {
1095 (void)JumpScopeChecker(Body, *this);
1096}
1097