Bug Summary

File:clang/lib/Sema/SemaExceptionSpec.cpp
Warning:line 390, column 9
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name SemaExceptionSpec.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/clang/include -I tools/clang/include -I include -I /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fmacro-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -O3 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-01-16-232930-107970-1 -x c++ /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/clang/lib/Sema/SemaExceptionSpec.cpp
1//===--- SemaExceptionSpec.cpp - C++ Exception Specifications ---*- 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 provides Sema routines for C++ exception specification testing.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/Sema/SemaInternal.h"
14#include "clang/AST/ASTMutationListener.h"
15#include "clang/AST/CXXInheritance.h"
16#include "clang/AST/Expr.h"
17#include "clang/AST/ExprCXX.h"
18#include "clang/AST/StmtObjC.h"
19#include "clang/AST/TypeLoc.h"
20#include "clang/Basic/Diagnostic.h"
21#include "clang/Basic/SourceManager.h"
22#include "llvm/ADT/SmallPtrSet.h"
23#include "llvm/ADT/SmallString.h"
24
25namespace clang {
26
27static const FunctionProtoType *GetUnderlyingFunction(QualType T)
28{
29 if (const PointerType *PtrTy = T->getAs<PointerType>())
30 T = PtrTy->getPointeeType();
31 else if (const ReferenceType *RefTy = T->getAs<ReferenceType>())
32 T = RefTy->getPointeeType();
33 else if (const MemberPointerType *MPTy = T->getAs<MemberPointerType>())
34 T = MPTy->getPointeeType();
35 return T->getAs<FunctionProtoType>();
36}
37
38/// HACK: 2014-11-14 libstdc++ had a bug where it shadows std::swap with a
39/// member swap function then tries to call std::swap unqualified from the
40/// exception specification of that function. This function detects whether
41/// we're in such a case and turns off delay-parsing of exception
42/// specifications. Libstdc++ 6.1 (released 2016-04-27) appears to have
43/// resolved it as side-effect of commit ddb63209a8d (2015-06-05).
44bool Sema::isLibstdcxxEagerExceptionSpecHack(const Declarator &D) {
45 auto *RD = dyn_cast<CXXRecordDecl>(CurContext);
46
47 // All the problem cases are member functions named "swap" within class
48 // templates declared directly within namespace std or std::__debug or
49 // std::__profile.
50 if (!RD || !RD->getIdentifier() || !RD->getDescribedClassTemplate() ||
51 !D.getIdentifier() || !D.getIdentifier()->isStr("swap"))
52 return false;
53
54 auto *ND = dyn_cast<NamespaceDecl>(RD->getDeclContext());
55 if (!ND)
56 return false;
57
58 bool IsInStd = ND->isStdNamespace();
59 if (!IsInStd) {
60 // This isn't a direct member of namespace std, but it might still be
61 // libstdc++'s std::__debug::array or std::__profile::array.
62 IdentifierInfo *II = ND->getIdentifier();
63 if (!II || !(II->isStr("__debug") || II->isStr("__profile")) ||
64 !ND->isInStdNamespace())
65 return false;
66 }
67
68 // Only apply this hack within a system header.
69 if (!Context.getSourceManager().isInSystemHeader(D.getBeginLoc()))
70 return false;
71
72 return llvm::StringSwitch<bool>(RD->getIdentifier()->getName())
73 .Case("array", true)
74 .Case("pair", IsInStd)
75 .Case("priority_queue", IsInStd)
76 .Case("stack", IsInStd)
77 .Case("queue", IsInStd)
78 .Default(false);
79}
80
81ExprResult Sema::ActOnNoexceptSpec(Expr *NoexceptExpr,
82 ExceptionSpecificationType &EST) {
83
84 if (NoexceptExpr->isTypeDependent() ||
85 NoexceptExpr->containsUnexpandedParameterPack()) {
86 EST = EST_DependentNoexcept;
87 return NoexceptExpr;
88 }
89
90 llvm::APSInt Result;
91 ExprResult Converted = CheckConvertedConstantExpression(
92 NoexceptExpr, Context.BoolTy, Result, CCEK_Noexcept);
93
94 if (Converted.isInvalid()) {
95 EST = EST_NoexceptFalse;
96 // Fill in an expression of 'false' as a fixup.
97 auto *BoolExpr = new (Context)
98 CXXBoolLiteralExpr(false, Context.BoolTy, NoexceptExpr->getBeginLoc());
99 llvm::APSInt Value{1};
100 Value = 0;
101 return ConstantExpr::Create(Context, BoolExpr, APValue{Value});
102 }
103
104 if (Converted.get()->isValueDependent()) {
105 EST = EST_DependentNoexcept;
106 return Converted;
107 }
108
109 if (!Converted.isInvalid())
110 EST = !Result ? EST_NoexceptFalse : EST_NoexceptTrue;
111 return Converted;
112}
113
114/// CheckSpecifiedExceptionType - Check if the given type is valid in an
115/// exception specification. Incomplete types, or pointers to incomplete types
116/// other than void are not allowed.
117///
118/// \param[in,out] T The exception type. This will be decayed to a pointer type
119/// when the input is an array or a function type.
120bool Sema::CheckSpecifiedExceptionType(QualType &T, SourceRange Range) {
121 // C++11 [except.spec]p2:
122 // A type cv T, "array of T", or "function returning T" denoted
123 // in an exception-specification is adjusted to type T, "pointer to T", or
124 // "pointer to function returning T", respectively.
125 //
126 // We also apply this rule in C++98.
127 if (T->isArrayType())
128 T = Context.getArrayDecayedType(T);
129 else if (T->isFunctionType())
130 T = Context.getPointerType(T);
131
132 int Kind = 0;
133 QualType PointeeT = T;
134 if (const PointerType *PT = T->getAs<PointerType>()) {
135 PointeeT = PT->getPointeeType();
136 Kind = 1;
137
138 // cv void* is explicitly permitted, despite being a pointer to an
139 // incomplete type.
140 if (PointeeT->isVoidType())
141 return false;
142 } else if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
143 PointeeT = RT->getPointeeType();
144 Kind = 2;
145
146 if (RT->isRValueReferenceType()) {
147 // C++11 [except.spec]p2:
148 // A type denoted in an exception-specification shall not denote [...]
149 // an rvalue reference type.
150 Diag(Range.getBegin(), diag::err_rref_in_exception_spec)
151 << T << Range;
152 return true;
153 }
154 }
155
156 // C++11 [except.spec]p2:
157 // A type denoted in an exception-specification shall not denote an
158 // incomplete type other than a class currently being defined [...].
159 // A type denoted in an exception-specification shall not denote a
160 // pointer or reference to an incomplete type, other than (cv) void* or a
161 // pointer or reference to a class currently being defined.
162 // In Microsoft mode, downgrade this to a warning.
163 unsigned DiagID = diag::err_incomplete_in_exception_spec;
164 bool ReturnValueOnError = true;
165 if (getLangOpts().MSVCCompat) {
166 DiagID = diag::ext_incomplete_in_exception_spec;
167 ReturnValueOnError = false;
168 }
169 if (!(PointeeT->isRecordType() &&
170 PointeeT->castAs<RecordType>()->isBeingDefined()) &&
171 RequireCompleteType(Range.getBegin(), PointeeT, DiagID, Kind, Range))
172 return ReturnValueOnError;
173
174 // The MSVC compatibility mode doesn't extend to sizeless types,
175 // so diagnose them separately.
176 if (PointeeT->isSizelessType() && Kind != 1) {
177 Diag(Range.getBegin(), diag::err_sizeless_in_exception_spec)
178 << (Kind == 2 ? 1 : 0) << PointeeT << Range;
179 return true;
180 }
181
182 return false;
183}
184
185/// CheckDistantExceptionSpec - Check if the given type is a pointer or pointer
186/// to member to a function with an exception specification. This means that
187/// it is invalid to add another level of indirection.
188bool Sema::CheckDistantExceptionSpec(QualType T) {
189 // C++17 removes this rule in favor of putting exception specifications into
190 // the type system.
191 if (getLangOpts().CPlusPlus17)
192 return false;
193
194 if (const PointerType *PT = T->getAs<PointerType>())
195 T = PT->getPointeeType();
196 else if (const MemberPointerType *PT = T->getAs<MemberPointerType>())
197 T = PT->getPointeeType();
198 else
199 return false;
200
201 const FunctionProtoType *FnT = T->getAs<FunctionProtoType>();
202 if (!FnT)
203 return false;
204
205 return FnT->hasExceptionSpec();
206}
207
208const FunctionProtoType *
209Sema::ResolveExceptionSpec(SourceLocation Loc, const FunctionProtoType *FPT) {
210 if (FPT->getExceptionSpecType() == EST_Unparsed) {
211 Diag(Loc, diag::err_exception_spec_not_parsed);
212 return nullptr;
213 }
214
215 if (!isUnresolvedExceptionSpec(FPT->getExceptionSpecType()))
216 return FPT;
217
218 FunctionDecl *SourceDecl = FPT->getExceptionSpecDecl();
219 const FunctionProtoType *SourceFPT =
220 SourceDecl->getType()->castAs<FunctionProtoType>();
221
222 // If the exception specification has already been resolved, just return it.
223 if (!isUnresolvedExceptionSpec(SourceFPT->getExceptionSpecType()))
224 return SourceFPT;
225
226 // Compute or instantiate the exception specification now.
227 if (SourceFPT->getExceptionSpecType() == EST_Unevaluated)
228 EvaluateImplicitExceptionSpec(Loc, SourceDecl);
229 else
230 InstantiateExceptionSpec(Loc, SourceDecl);
231
232 const FunctionProtoType *Proto =
233 SourceDecl->getType()->castAs<FunctionProtoType>();
234 if (Proto->getExceptionSpecType() == clang::EST_Unparsed) {
235 Diag(Loc, diag::err_exception_spec_not_parsed);
236 Proto = nullptr;
237 }
238 return Proto;
239}
240
241void
242Sema::UpdateExceptionSpec(FunctionDecl *FD,
243 const FunctionProtoType::ExceptionSpecInfo &ESI) {
244 // If we've fully resolved the exception specification, notify listeners.
245 if (!isUnresolvedExceptionSpec(ESI.Type))
246 if (auto *Listener = getASTMutationListener())
247 Listener->ResolvedExceptionSpec(FD);
248
249 for (FunctionDecl *Redecl : FD->redecls())
250 Context.adjustExceptionSpec(Redecl, ESI);
251}
252
253static bool exceptionSpecNotKnownYet(const FunctionDecl *FD) {
254 auto *MD = dyn_cast<CXXMethodDecl>(FD);
4
Assuming 'FD' is not a 'CXXMethodDecl'
9
Assuming 'FD' is not a 'CXXMethodDecl'
255 if (!MD
4.1
'MD' is null
9.1
'MD' is null
)
5
Taking true branch
10
Taking true branch
256 return false;
6
Returning zero, which participates in a condition later
11
Returning zero, which participates in a condition later
257
258 auto EST = MD->getType()->castAs<FunctionProtoType>()->getExceptionSpecType();
259 return EST == EST_Unparsed ||
260 (EST == EST_Unevaluated && MD->getParent()->isBeingDefined());
261}
262
263static bool CheckEquivalentExceptionSpecImpl(
264 Sema &S, const PartialDiagnostic &DiagID, const PartialDiagnostic &NoteID,
265 const FunctionProtoType *Old, SourceLocation OldLoc,
266 const FunctionProtoType *New, SourceLocation NewLoc,
267 bool *MissingExceptionSpecification = nullptr,
268 bool *MissingEmptyExceptionSpecification = nullptr,
269 bool AllowNoexceptAllMatchWithNoSpec = false, bool IsOperatorNew = false);
270
271/// Determine whether a function has an implicitly-generated exception
272/// specification.
273static bool hasImplicitExceptionSpec(FunctionDecl *Decl) {
274 if (!isa<CXXDestructorDecl>(Decl) &&
275 Decl->getDeclName().getCXXOverloadedOperator() != OO_Delete &&
276 Decl->getDeclName().getCXXOverloadedOperator() != OO_Array_Delete)
277 return false;
278
279 // For a function that the user didn't declare:
280 // - if this is a destructor, its exception specification is implicit.
281 // - if this is 'operator delete' or 'operator delete[]', the exception
282 // specification is as-if an explicit exception specification was given
283 // (per [basic.stc.dynamic]p2).
284 if (!Decl->getTypeSourceInfo())
285 return isa<CXXDestructorDecl>(Decl);
286
287 auto *Ty = Decl->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
288 return !Ty->hasExceptionSpec();
289}
290
291bool Sema::CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New) {
292 // Just completely ignore this under -fno-exceptions prior to C++17.
293 // In C++17 onwards, the exception specification is part of the type and
294 // we will diagnose mismatches anyway, so it's better to check for them here.
295 if (!getLangOpts().CXXExceptions && !getLangOpts().CPlusPlus17)
1
Assuming field 'CXXExceptions' is not equal to 0
296 return false;
297
298 OverloadedOperatorKind OO = New->getDeclName().getCXXOverloadedOperator();
299 bool IsOperatorNew = OO
1.1
'OO' is not equal to OO_New
== OO_New || OO == OO_Array_New;
300 bool MissingExceptionSpecification = false;
301 bool MissingEmptyExceptionSpecification = false;
302
303 unsigned DiagID = diag::err_mismatched_exception_spec;
304 bool ReturnValueOnError = true;
305 if (getLangOpts().MSVCCompat) {
2
Assuming field 'MSVCCompat' is 0
306 DiagID = diag::ext_mismatched_exception_spec;
307 ReturnValueOnError = false;
308 }
309
310 // If we're befriending a member function of a class that's currently being
311 // defined, we might not be able to work out its exception specification yet.
312 // If not, defer the check until later.
313 if (exceptionSpecNotKnownYet(Old) || exceptionSpecNotKnownYet(New)) {
3
Calling 'exceptionSpecNotKnownYet'
7
Returning from 'exceptionSpecNotKnownYet'
8
Calling 'exceptionSpecNotKnownYet'
12
Returning from 'exceptionSpecNotKnownYet'
13
Taking false branch
314 DelayedEquivalentExceptionSpecChecks.push_back({New, Old});
315 return false;
316 }
317
318 // Check the types as written: they must match before any exception
319 // specification adjustment is applied.
320 if (!CheckEquivalentExceptionSpecImpl(
16
Assuming the condition is false
17
Taking false branch
321 *this, PDiag(DiagID), PDiag(diag::note_previous_declaration),
322 Old->getType()->getAs<FunctionProtoType>(), Old->getLocation(),
14
Assuming the object is not a 'FunctionProtoType'
323 New->getType()->getAs<FunctionProtoType>(), New->getLocation(),
15
Assuming the object is not a 'FunctionProtoType'
324 &MissingExceptionSpecification, &MissingEmptyExceptionSpecification,
325 /*AllowNoexceptAllMatchWithNoSpec=*/true, IsOperatorNew)) {
326 // C++11 [except.spec]p4 [DR1492]:
327 // If a declaration of a function has an implicit
328 // exception-specification, other declarations of the function shall
329 // not specify an exception-specification.
330 if (getLangOpts().CPlusPlus11 && getLangOpts().CXXExceptions &&
331 hasImplicitExceptionSpec(Old) != hasImplicitExceptionSpec(New)) {
332 Diag(New->getLocation(), diag::ext_implicit_exception_spec_mismatch)
333 << hasImplicitExceptionSpec(Old);
334 if (Old->getLocation().isValid())
335 Diag(Old->getLocation(), diag::note_previous_declaration);
336 }
337 return false;
338 }
339
340 // The failure was something other than an missing exception
341 // specification; return an error, except in MS mode where this is a warning.
342 if (!MissingExceptionSpecification)
18
Assuming 'MissingExceptionSpecification' is true
19
Taking false branch
343 return ReturnValueOnError;
344
345 const FunctionProtoType *NewProto =
21
'NewProto' initialized here
346 New->getType()->castAs<FunctionProtoType>();
20
The object is a 'FunctionProtoType'
347
348 // The new function declaration is only missing an empty exception
349 // specification "throw()". If the throw() specification came from a
350 // function in a system header that has C linkage, just add an empty
351 // exception specification to the "new" declaration. Note that C library
352 // implementations are permitted to add these nothrow exception
353 // specifications.
354 //
355 // Likewise if the old function is a builtin.
356 if (MissingEmptyExceptionSpecification && NewProto &&
22
Assuming 'MissingEmptyExceptionSpecification' is true
23
Assuming 'NewProto' is null
24
Assuming pointer value is null
25
Taking false branch
357 (Old->getLocation().isInvalid() ||
358 Context.getSourceManager().isInSystemHeader(Old->getLocation()) ||
359 Old->getBuiltinID()) &&
360 Old->isExternC()) {
361 New->setType(Context.getFunctionType(
362 NewProto->getReturnType(), NewProto->getParamTypes(),
363 NewProto->getExtProtoInfo().withExceptionSpec(EST_DynamicNone)));
364 return false;
365 }
366
367 const FunctionProtoType *OldProto =
368 Old->getType()->castAs<FunctionProtoType>();
26
The object is a 'FunctionProtoType'
369
370 FunctionProtoType::ExceptionSpecInfo ESI = OldProto->getExceptionSpecType();
371 if (ESI.Type == EST_Dynamic) {
27
Assuming field 'Type' is not equal to EST_Dynamic
28
Taking false branch
372 // FIXME: What if the exceptions are described in terms of the old
373 // prototype's parameters?
374 ESI.Exceptions = OldProto->exceptions();
375 }
376
377 if (ESI.Type == EST_NoexceptFalse)
29
Assuming field 'Type' is not equal to EST_NoexceptFalse
30
Taking false branch
378 ESI.Type = EST_None;
379 if (ESI.Type == EST_NoexceptTrue)
31
Assuming field 'Type' is not equal to EST_NoexceptTrue
32
Taking false branch
380 ESI.Type = EST_BasicNoexcept;
381
382 // For dependent noexcept, we can't just take the expression from the old
383 // prototype. It likely contains references to the old prototype's parameters.
384 if (ESI.Type == EST_DependentNoexcept) {
33
Assuming field 'Type' is not equal to EST_DependentNoexcept
34
Taking false branch
385 New->setInvalidDecl();
386 } else {
387 // Update the type of the function with the appropriate exception
388 // specification.
389 New->setType(Context.getFunctionType(
390 NewProto->getReturnType(), NewProto->getParamTypes(),
35
Called C++ object pointer is null
391 NewProto->getExtProtoInfo().withExceptionSpec(ESI)));
392 }
393
394 if (getLangOpts().MSVCCompat && isDynamicExceptionSpec(ESI.Type)) {
395 DiagID = diag::ext_missing_exception_specification;
396 ReturnValueOnError = false;
397 } else if (New->isReplaceableGlobalAllocationFunction() &&
398 ESI.Type != EST_DependentNoexcept) {
399 // Allow missing exception specifications in redeclarations as an extension,
400 // when declaring a replaceable global allocation function.
401 DiagID = diag::ext_missing_exception_specification;
402 ReturnValueOnError = false;
403 } else if (ESI.Type == EST_NoThrow) {
404 // Don't emit any warning for missing 'nothrow' in MSVC.
405 if (getLangOpts().MSVCCompat) {
406 return false;
407 }
408 // Allow missing attribute 'nothrow' in redeclarations, since this is a very
409 // common omission.
410 DiagID = diag::ext_missing_exception_specification;
411 ReturnValueOnError = false;
412 } else {
413 DiagID = diag::err_missing_exception_specification;
414 ReturnValueOnError = true;
415 }
416
417 // Warn about the lack of exception specification.
418 SmallString<128> ExceptionSpecString;
419 llvm::raw_svector_ostream OS(ExceptionSpecString);
420 switch (OldProto->getExceptionSpecType()) {
421 case EST_DynamicNone:
422 OS << "throw()";
423 break;
424
425 case EST_Dynamic: {
426 OS << "throw(";
427 bool OnFirstException = true;
428 for (const auto &E : OldProto->exceptions()) {
429 if (OnFirstException)
430 OnFirstException = false;
431 else
432 OS << ", ";
433
434 OS << E.getAsString(getPrintingPolicy());
435 }
436 OS << ")";
437 break;
438 }
439
440 case EST_BasicNoexcept:
441 OS << "noexcept";
442 break;
443
444 case EST_DependentNoexcept:
445 case EST_NoexceptFalse:
446 case EST_NoexceptTrue:
447 OS << "noexcept(";
448 assert(OldProto->getNoexceptExpr() != nullptr && "Expected non-null Expr")(static_cast <bool> (OldProto->getNoexceptExpr() != nullptr
&& "Expected non-null Expr") ? void (0) : __assert_fail
("OldProto->getNoexceptExpr() != nullptr && \"Expected non-null Expr\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 448, __extension__ __PRETTY_FUNCTION__
))
;
449 OldProto->getNoexceptExpr()->printPretty(OS, nullptr, getPrintingPolicy());
450 OS << ")";
451 break;
452 case EST_NoThrow:
453 OS <<"__attribute__((nothrow))";
454 break;
455 case EST_None:
456 case EST_MSAny:
457 case EST_Unevaluated:
458 case EST_Uninstantiated:
459 case EST_Unparsed:
460 llvm_unreachable("This spec type is compatible with none.")::llvm::llvm_unreachable_internal("This spec type is compatible with none."
, "clang/lib/Sema/SemaExceptionSpec.cpp", 460)
;
461 }
462
463 SourceLocation FixItLoc;
464 if (TypeSourceInfo *TSInfo = New->getTypeSourceInfo()) {
465 TypeLoc TL = TSInfo->getTypeLoc().IgnoreParens();
466 // FIXME: Preserve enough information so that we can produce a correct fixit
467 // location when there is a trailing return type.
468 if (auto FTLoc = TL.getAs<FunctionProtoTypeLoc>())
469 if (!FTLoc.getTypePtr()->hasTrailingReturn())
470 FixItLoc = getLocForEndOfToken(FTLoc.getLocalRangeEnd());
471 }
472
473 if (FixItLoc.isInvalid())
474 Diag(New->getLocation(), DiagID)
475 << New << OS.str();
476 else {
477 Diag(New->getLocation(), DiagID)
478 << New << OS.str()
479 << FixItHint::CreateInsertion(FixItLoc, " " + OS.str().str());
480 }
481
482 if (Old->getLocation().isValid())
483 Diag(Old->getLocation(), diag::note_previous_declaration);
484
485 return ReturnValueOnError;
486}
487
488/// CheckEquivalentExceptionSpec - Check if the two types have equivalent
489/// exception specifications. Exception specifications are equivalent if
490/// they allow exactly the same set of exception types. It does not matter how
491/// that is achieved. See C++ [except.spec]p2.
492bool Sema::CheckEquivalentExceptionSpec(
493 const FunctionProtoType *Old, SourceLocation OldLoc,
494 const FunctionProtoType *New, SourceLocation NewLoc) {
495 if (!getLangOpts().CXXExceptions)
496 return false;
497
498 unsigned DiagID = diag::err_mismatched_exception_spec;
499 if (getLangOpts().MSVCCompat)
500 DiagID = diag::ext_mismatched_exception_spec;
501 bool Result = CheckEquivalentExceptionSpecImpl(
502 *this, PDiag(DiagID), PDiag(diag::note_previous_declaration),
503 Old, OldLoc, New, NewLoc);
504
505 // In Microsoft mode, mismatching exception specifications just cause a warning.
506 if (getLangOpts().MSVCCompat)
507 return false;
508 return Result;
509}
510
511/// CheckEquivalentExceptionSpec - Check if the two types have compatible
512/// exception specifications. See C++ [except.spec]p3.
513///
514/// \return \c false if the exception specifications match, \c true if there is
515/// a problem. If \c true is returned, either a diagnostic has already been
516/// produced or \c *MissingExceptionSpecification is set to \c true.
517static bool CheckEquivalentExceptionSpecImpl(
518 Sema &S, const PartialDiagnostic &DiagID, const PartialDiagnostic &NoteID,
519 const FunctionProtoType *Old, SourceLocation OldLoc,
520 const FunctionProtoType *New, SourceLocation NewLoc,
521 bool *MissingExceptionSpecification,
522 bool *MissingEmptyExceptionSpecification,
523 bool AllowNoexceptAllMatchWithNoSpec, bool IsOperatorNew) {
524 if (MissingExceptionSpecification)
525 *MissingExceptionSpecification = false;
526
527 if (MissingEmptyExceptionSpecification)
528 *MissingEmptyExceptionSpecification = false;
529
530 Old = S.ResolveExceptionSpec(NewLoc, Old);
531 if (!Old)
532 return false;
533 New = S.ResolveExceptionSpec(NewLoc, New);
534 if (!New)
535 return false;
536
537 // C++0x [except.spec]p3: Two exception-specifications are compatible if:
538 // - both are non-throwing, regardless of their form,
539 // - both have the form noexcept(constant-expression) and the constant-
540 // expressions are equivalent,
541 // - both are dynamic-exception-specifications that have the same set of
542 // adjusted types.
543 //
544 // C++0x [except.spec]p12: An exception-specification is non-throwing if it is
545 // of the form throw(), noexcept, or noexcept(constant-expression) where the
546 // constant-expression yields true.
547 //
548 // C++0x [except.spec]p4: If any declaration of a function has an exception-
549 // specifier that is not a noexcept-specification allowing all exceptions,
550 // all declarations [...] of that function shall have a compatible
551 // exception-specification.
552 //
553 // That last point basically means that noexcept(false) matches no spec.
554 // It's considered when AllowNoexceptAllMatchWithNoSpec is true.
555
556 ExceptionSpecificationType OldEST = Old->getExceptionSpecType();
557 ExceptionSpecificationType NewEST = New->getExceptionSpecType();
558
559 assert(!isUnresolvedExceptionSpec(OldEST) &&(static_cast <bool> (!isUnresolvedExceptionSpec(OldEST)
&& !isUnresolvedExceptionSpec(NewEST) && "Shouldn't see unknown exception specifications here"
) ? void (0) : __assert_fail ("!isUnresolvedExceptionSpec(OldEST) && !isUnresolvedExceptionSpec(NewEST) && \"Shouldn't see unknown exception specifications here\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 561, __extension__ __PRETTY_FUNCTION__
))
560 !isUnresolvedExceptionSpec(NewEST) &&(static_cast <bool> (!isUnresolvedExceptionSpec(OldEST)
&& !isUnresolvedExceptionSpec(NewEST) && "Shouldn't see unknown exception specifications here"
) ? void (0) : __assert_fail ("!isUnresolvedExceptionSpec(OldEST) && !isUnresolvedExceptionSpec(NewEST) && \"Shouldn't see unknown exception specifications here\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 561, __extension__ __PRETTY_FUNCTION__
))
561 "Shouldn't see unknown exception specifications here")(static_cast <bool> (!isUnresolvedExceptionSpec(OldEST)
&& !isUnresolvedExceptionSpec(NewEST) && "Shouldn't see unknown exception specifications here"
) ? void (0) : __assert_fail ("!isUnresolvedExceptionSpec(OldEST) && !isUnresolvedExceptionSpec(NewEST) && \"Shouldn't see unknown exception specifications here\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 561, __extension__ __PRETTY_FUNCTION__
))
;
562
563 CanThrowResult OldCanThrow = Old->canThrow();
564 CanThrowResult NewCanThrow = New->canThrow();
565
566 // Any non-throwing specifications are compatible.
567 if (OldCanThrow == CT_Cannot && NewCanThrow == CT_Cannot)
568 return false;
569
570 // Any throws-anything specifications are usually compatible.
571 if (OldCanThrow == CT_Can && OldEST != EST_Dynamic &&
572 NewCanThrow == CT_Can && NewEST != EST_Dynamic) {
573 // The exception is that the absence of an exception specification only
574 // matches noexcept(false) for functions, as described above.
575 if (!AllowNoexceptAllMatchWithNoSpec &&
576 ((OldEST == EST_None && NewEST == EST_NoexceptFalse) ||
577 (OldEST == EST_NoexceptFalse && NewEST == EST_None))) {
578 // This is the disallowed case.
579 } else {
580 return false;
581 }
582 }
583
584 // C++14 [except.spec]p3:
585 // Two exception-specifications are compatible if [...] both have the form
586 // noexcept(constant-expression) and the constant-expressions are equivalent
587 if (OldEST == EST_DependentNoexcept && NewEST == EST_DependentNoexcept) {
588 llvm::FoldingSetNodeID OldFSN, NewFSN;
589 Old->getNoexceptExpr()->Profile(OldFSN, S.Context, true);
590 New->getNoexceptExpr()->Profile(NewFSN, S.Context, true);
591 if (OldFSN == NewFSN)
592 return false;
593 }
594
595 // Dynamic exception specifications with the same set of adjusted types
596 // are compatible.
597 if (OldEST == EST_Dynamic && NewEST == EST_Dynamic) {
598 bool Success = true;
599 // Both have a dynamic exception spec. Collect the first set, then compare
600 // to the second.
601 llvm::SmallPtrSet<CanQualType, 8> OldTypes, NewTypes;
602 for (const auto &I : Old->exceptions())
603 OldTypes.insert(S.Context.getCanonicalType(I).getUnqualifiedType());
604
605 for (const auto &I : New->exceptions()) {
606 CanQualType TypePtr = S.Context.getCanonicalType(I).getUnqualifiedType();
607 if (OldTypes.count(TypePtr))
608 NewTypes.insert(TypePtr);
609 else {
610 Success = false;
611 break;
612 }
613 }
614
615 if (Success && OldTypes.size() == NewTypes.size())
616 return false;
617 }
618
619 // As a special compatibility feature, under C++0x we accept no spec and
620 // throw(std::bad_alloc) as equivalent for operator new and operator new[].
621 // This is because the implicit declaration changed, but old code would break.
622 if (S.getLangOpts().CPlusPlus11 && IsOperatorNew) {
623 const FunctionProtoType *WithExceptions = nullptr;
624 if (OldEST == EST_None && NewEST == EST_Dynamic)
625 WithExceptions = New;
626 else if (OldEST == EST_Dynamic && NewEST == EST_None)
627 WithExceptions = Old;
628 if (WithExceptions && WithExceptions->getNumExceptions() == 1) {
629 // One has no spec, the other throw(something). If that something is
630 // std::bad_alloc, all conditions are met.
631 QualType Exception = *WithExceptions->exception_begin();
632 if (CXXRecordDecl *ExRecord = Exception->getAsCXXRecordDecl()) {
633 IdentifierInfo* Name = ExRecord->getIdentifier();
634 if (Name && Name->getName() == "bad_alloc") {
635 // It's called bad_alloc, but is it in std?
636 if (ExRecord->isInStdNamespace()) {
637 return false;
638 }
639 }
640 }
641 }
642 }
643
644 // If the caller wants to handle the case that the new function is
645 // incompatible due to a missing exception specification, let it.
646 if (MissingExceptionSpecification && OldEST != EST_None &&
647 NewEST == EST_None) {
648 // The old type has an exception specification of some sort, but
649 // the new type does not.
650 *MissingExceptionSpecification = true;
651
652 if (MissingEmptyExceptionSpecification && OldCanThrow == CT_Cannot) {
653 // The old type has a throw() or noexcept(true) exception specification
654 // and the new type has no exception specification, and the caller asked
655 // to handle this itself.
656 *MissingEmptyExceptionSpecification = true;
657 }
658
659 return true;
660 }
661
662 S.Diag(NewLoc, DiagID);
663 if (NoteID.getDiagID() != 0 && OldLoc.isValid())
664 S.Diag(OldLoc, NoteID);
665 return true;
666}
667
668bool Sema::CheckEquivalentExceptionSpec(const PartialDiagnostic &DiagID,
669 const PartialDiagnostic &NoteID,
670 const FunctionProtoType *Old,
671 SourceLocation OldLoc,
672 const FunctionProtoType *New,
673 SourceLocation NewLoc) {
674 if (!getLangOpts().CXXExceptions)
675 return false;
676 return CheckEquivalentExceptionSpecImpl(*this, DiagID, NoteID, Old, OldLoc,
677 New, NewLoc);
678}
679
680bool Sema::handlerCanCatch(QualType HandlerType, QualType ExceptionType) {
681 // [except.handle]p3:
682 // A handler is a match for an exception object of type E if:
683
684 // HandlerType must be ExceptionType or derived from it, or pointer or
685 // reference to such types.
686 const ReferenceType *RefTy = HandlerType->getAs<ReferenceType>();
687 if (RefTy)
688 HandlerType = RefTy->getPointeeType();
689
690 // -- the handler is of type cv T or cv T& and E and T are the same type
691 if (Context.hasSameUnqualifiedType(ExceptionType, HandlerType))
692 return true;
693
694 // FIXME: ObjC pointer types?
695 if (HandlerType->isPointerType() || HandlerType->isMemberPointerType()) {
696 if (RefTy && (!HandlerType.isConstQualified() ||
697 HandlerType.isVolatileQualified()))
698 return false;
699
700 // -- the handler is of type cv T or const T& where T is a pointer or
701 // pointer to member type and E is std::nullptr_t
702 if (ExceptionType->isNullPtrType())
703 return true;
704
705 // -- the handler is of type cv T or const T& where T is a pointer or
706 // pointer to member type and E is a pointer or pointer to member type
707 // that can be converted to T by one or more of
708 // -- a qualification conversion
709 // -- a function pointer conversion
710 bool LifetimeConv;
711 QualType Result;
712 // FIXME: Should we treat the exception as catchable if a lifetime
713 // conversion is required?
714 if (IsQualificationConversion(ExceptionType, HandlerType, false,
715 LifetimeConv) ||
716 IsFunctionConversion(ExceptionType, HandlerType, Result))
717 return true;
718
719 // -- a standard pointer conversion [...]
720 if (!ExceptionType->isPointerType() || !HandlerType->isPointerType())
721 return false;
722
723 // Handle the "qualification conversion" portion.
724 Qualifiers EQuals, HQuals;
725 ExceptionType = Context.getUnqualifiedArrayType(
726 ExceptionType->getPointeeType(), EQuals);
727 HandlerType = Context.getUnqualifiedArrayType(
728 HandlerType->getPointeeType(), HQuals);
729 if (!HQuals.compatiblyIncludes(EQuals))
730 return false;
731
732 if (HandlerType->isVoidType() && ExceptionType->isObjectType())
733 return true;
734
735 // The only remaining case is a derived-to-base conversion.
736 }
737
738 // -- the handler is of type cg T or cv T& and T is an unambiguous public
739 // base class of E
740 if (!ExceptionType->isRecordType() || !HandlerType->isRecordType())
741 return false;
742 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
743 /*DetectVirtual=*/false);
744 if (!IsDerivedFrom(SourceLocation(), ExceptionType, HandlerType, Paths) ||
745 Paths.isAmbiguous(Context.getCanonicalType(HandlerType)))
746 return false;
747
748 // Do this check from a context without privileges.
749 switch (CheckBaseClassAccess(SourceLocation(), HandlerType, ExceptionType,
750 Paths.front(),
751 /*Diagnostic*/ 0,
752 /*ForceCheck*/ true,
753 /*ForceUnprivileged*/ true)) {
754 case AR_accessible: return true;
755 case AR_inaccessible: return false;
756 case AR_dependent:
757 llvm_unreachable("access check dependent for unprivileged context")::llvm::llvm_unreachable_internal("access check dependent for unprivileged context"
, "clang/lib/Sema/SemaExceptionSpec.cpp", 757)
;
758 case AR_delayed:
759 llvm_unreachable("access check delayed in non-declaration")::llvm::llvm_unreachable_internal("access check delayed in non-declaration"
, "clang/lib/Sema/SemaExceptionSpec.cpp", 759)
;
760 }
761 llvm_unreachable("unexpected access check result")::llvm::llvm_unreachable_internal("unexpected access check result"
, "clang/lib/Sema/SemaExceptionSpec.cpp", 761)
;
762}
763
764/// CheckExceptionSpecSubset - Check whether the second function type's
765/// exception specification is a subset (or equivalent) of the first function
766/// type. This is used by override and pointer assignment checks.
767bool Sema::CheckExceptionSpecSubset(const PartialDiagnostic &DiagID,
768 const PartialDiagnostic &NestedDiagID,
769 const PartialDiagnostic &NoteID,
770 const PartialDiagnostic &NoThrowDiagID,
771 const FunctionProtoType *Superset,
772 SourceLocation SuperLoc,
773 const FunctionProtoType *Subset,
774 SourceLocation SubLoc) {
775
776 // Just auto-succeed under -fno-exceptions.
777 if (!getLangOpts().CXXExceptions)
778 return false;
779
780 // FIXME: As usual, we could be more specific in our error messages, but
781 // that better waits until we've got types with source locations.
782
783 if (!SubLoc.isValid())
784 SubLoc = SuperLoc;
785
786 // Resolve the exception specifications, if needed.
787 Superset = ResolveExceptionSpec(SuperLoc, Superset);
788 if (!Superset)
789 return false;
790 Subset = ResolveExceptionSpec(SubLoc, Subset);
791 if (!Subset)
792 return false;
793
794 ExceptionSpecificationType SuperEST = Superset->getExceptionSpecType();
795 ExceptionSpecificationType SubEST = Subset->getExceptionSpecType();
796 assert(!isUnresolvedExceptionSpec(SuperEST) &&(static_cast <bool> (!isUnresolvedExceptionSpec(SuperEST
) && !isUnresolvedExceptionSpec(SubEST) && "Shouldn't see unknown exception specifications here"
) ? void (0) : __assert_fail ("!isUnresolvedExceptionSpec(SuperEST) && !isUnresolvedExceptionSpec(SubEST) && \"Shouldn't see unknown exception specifications here\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 798, __extension__ __PRETTY_FUNCTION__
))
797 !isUnresolvedExceptionSpec(SubEST) &&(static_cast <bool> (!isUnresolvedExceptionSpec(SuperEST
) && !isUnresolvedExceptionSpec(SubEST) && "Shouldn't see unknown exception specifications here"
) ? void (0) : __assert_fail ("!isUnresolvedExceptionSpec(SuperEST) && !isUnresolvedExceptionSpec(SubEST) && \"Shouldn't see unknown exception specifications here\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 798, __extension__ __PRETTY_FUNCTION__
))
798 "Shouldn't see unknown exception specifications here")(static_cast <bool> (!isUnresolvedExceptionSpec(SuperEST
) && !isUnresolvedExceptionSpec(SubEST) && "Shouldn't see unknown exception specifications here"
) ? void (0) : __assert_fail ("!isUnresolvedExceptionSpec(SuperEST) && !isUnresolvedExceptionSpec(SubEST) && \"Shouldn't see unknown exception specifications here\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 798, __extension__ __PRETTY_FUNCTION__
))
;
799
800 // If there are dependent noexcept specs, assume everything is fine. Unlike
801 // with the equivalency check, this is safe in this case, because we don't
802 // want to merge declarations. Checks after instantiation will catch any
803 // omissions we make here.
804 if (SuperEST == EST_DependentNoexcept || SubEST == EST_DependentNoexcept)
805 return false;
806
807 CanThrowResult SuperCanThrow = Superset->canThrow();
808 CanThrowResult SubCanThrow = Subset->canThrow();
809
810 // If the superset contains everything or the subset contains nothing, we're
811 // done.
812 if ((SuperCanThrow == CT_Can && SuperEST != EST_Dynamic) ||
813 SubCanThrow == CT_Cannot)
814 return CheckParamExceptionSpec(NestedDiagID, NoteID, Superset, SuperLoc,
815 Subset, SubLoc);
816
817 // Allow __declspec(nothrow) to be missing on redeclaration as an extension in
818 // some cases.
819 if (NoThrowDiagID.getDiagID() != 0 && SubCanThrow == CT_Can &&
820 SuperCanThrow == CT_Cannot && SuperEST == EST_NoThrow) {
821 Diag(SubLoc, NoThrowDiagID);
822 if (NoteID.getDiagID() != 0)
823 Diag(SuperLoc, NoteID);
824 return true;
825 }
826
827 // If the subset contains everything or the superset contains nothing, we've
828 // failed.
829 if ((SubCanThrow == CT_Can && SubEST != EST_Dynamic) ||
830 SuperCanThrow == CT_Cannot) {
831 Diag(SubLoc, DiagID);
832 if (NoteID.getDiagID() != 0)
833 Diag(SuperLoc, NoteID);
834 return true;
835 }
836
837 assert(SuperEST == EST_Dynamic && SubEST == EST_Dynamic &&(static_cast <bool> (SuperEST == EST_Dynamic &&
SubEST == EST_Dynamic && "Exception spec subset: non-dynamic case slipped through."
) ? void (0) : __assert_fail ("SuperEST == EST_Dynamic && SubEST == EST_Dynamic && \"Exception spec subset: non-dynamic case slipped through.\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 838, __extension__ __PRETTY_FUNCTION__
))
838 "Exception spec subset: non-dynamic case slipped through.")(static_cast <bool> (SuperEST == EST_Dynamic &&
SubEST == EST_Dynamic && "Exception spec subset: non-dynamic case slipped through."
) ? void (0) : __assert_fail ("SuperEST == EST_Dynamic && SubEST == EST_Dynamic && \"Exception spec subset: non-dynamic case slipped through.\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 838, __extension__ __PRETTY_FUNCTION__
))
;
839
840 // Neither contains everything or nothing. Do a proper comparison.
841 for (QualType SubI : Subset->exceptions()) {
842 if (const ReferenceType *RefTy = SubI->getAs<ReferenceType>())
843 SubI = RefTy->getPointeeType();
844
845 // Make sure it's in the superset.
846 bool Contained = false;
847 for (QualType SuperI : Superset->exceptions()) {
848 // [except.spec]p5:
849 // the target entity shall allow at least the exceptions allowed by the
850 // source
851 //
852 // We interpret this as meaning that a handler for some target type would
853 // catch an exception of each source type.
854 if (handlerCanCatch(SuperI, SubI)) {
855 Contained = true;
856 break;
857 }
858 }
859 if (!Contained) {
860 Diag(SubLoc, DiagID);
861 if (NoteID.getDiagID() != 0)
862 Diag(SuperLoc, NoteID);
863 return true;
864 }
865 }
866 // We've run half the gauntlet.
867 return CheckParamExceptionSpec(NestedDiagID, NoteID, Superset, SuperLoc,
868 Subset, SubLoc);
869}
870
871static bool
872CheckSpecForTypesEquivalent(Sema &S, const PartialDiagnostic &DiagID,
873 const PartialDiagnostic &NoteID, QualType Target,
874 SourceLocation TargetLoc, QualType Source,
875 SourceLocation SourceLoc) {
876 const FunctionProtoType *TFunc = GetUnderlyingFunction(Target);
877 if (!TFunc)
878 return false;
879 const FunctionProtoType *SFunc = GetUnderlyingFunction(Source);
880 if (!SFunc)
881 return false;
882
883 return S.CheckEquivalentExceptionSpec(DiagID, NoteID, TFunc, TargetLoc,
884 SFunc, SourceLoc);
885}
886
887/// CheckParamExceptionSpec - Check if the parameter and return types of the
888/// two functions have equivalent exception specs. This is part of the
889/// assignment and override compatibility check. We do not check the parameters
890/// of parameter function pointers recursively, as no sane programmer would
891/// even be able to write such a function type.
892bool Sema::CheckParamExceptionSpec(const PartialDiagnostic &DiagID,
893 const PartialDiagnostic &NoteID,
894 const FunctionProtoType *Target,
895 SourceLocation TargetLoc,
896 const FunctionProtoType *Source,
897 SourceLocation SourceLoc) {
898 auto RetDiag = DiagID;
899 RetDiag << 0;
900 if (CheckSpecForTypesEquivalent(
901 *this, RetDiag, PDiag(),
902 Target->getReturnType(), TargetLoc, Source->getReturnType(),
903 SourceLoc))
904 return true;
905
906 // We shouldn't even be testing this unless the arguments are otherwise
907 // compatible.
908 assert(Target->getNumParams() == Source->getNumParams() &&(static_cast <bool> (Target->getNumParams() == Source
->getNumParams() && "Functions have different argument counts."
) ? void (0) : __assert_fail ("Target->getNumParams() == Source->getNumParams() && \"Functions have different argument counts.\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 909, __extension__ __PRETTY_FUNCTION__
))
909 "Functions have different argument counts.")(static_cast <bool> (Target->getNumParams() == Source
->getNumParams() && "Functions have different argument counts."
) ? void (0) : __assert_fail ("Target->getNumParams() == Source->getNumParams() && \"Functions have different argument counts.\""
, "clang/lib/Sema/SemaExceptionSpec.cpp", 909, __extension__ __PRETTY_FUNCTION__
))
;
910 for (unsigned i = 0, E = Target->getNumParams(); i != E; ++i) {
911 auto ParamDiag = DiagID;
912 ParamDiag << 1;
913 if (CheckSpecForTypesEquivalent(
914 *this, ParamDiag, PDiag(),
915 Target->getParamType(i), TargetLoc, Source->getParamType(i),
916 SourceLoc))
917 return true;
918 }
919 return false;
920}
921
922bool Sema::CheckExceptionSpecCompatibility(Expr *From, QualType ToType) {
923 // First we check for applicability.
924 // Target type must be a function, function pointer or function reference.
925 const FunctionProtoType *ToFunc = GetUnderlyingFunction(ToType);
926 if (!ToFunc || ToFunc->hasDependentExceptionSpec())
927 return false;
928
929 // SourceType must be a function or function pointer.
930 const FunctionProtoType *FromFunc = GetUnderlyingFunction(From->getType());
931 if (!FromFunc || FromFunc->hasDependentExceptionSpec())
932 return false;
933
934 unsigned DiagID = diag::err_incompatible_exception_specs;
935 unsigned NestedDiagID = diag::err_deep_exception_specs_differ;
936 // This is not an error in C++17 onwards, unless the noexceptness doesn't
937 // match, but in that case we have a full-on type mismatch, not just a
938 // type sugar mismatch.
939 if (getLangOpts().CPlusPlus17) {
940 DiagID = diag::warn_incompatible_exception_specs;
941 NestedDiagID = diag::warn_deep_exception_specs_differ;
942 }
943
944 // Now we've got the correct types on both sides, check their compatibility.
945 // This means that the source of the conversion can only throw a subset of
946 // the exceptions of the target, and any exception specs on arguments or
947 // return types must be equivalent.
948 //
949 // FIXME: If there is a nested dependent exception specification, we should
950 // not be checking it here. This is fine:
951 // template<typename T> void f() {
952 // void (*p)(void (*) throw(T));
953 // void (*q)(void (*) throw(int)) = p;
954 // }
955 // ... because it might be instantiated with T=int.
956 return CheckExceptionSpecSubset(
957 PDiag(DiagID), PDiag(NestedDiagID), PDiag(), PDiag(), ToFunc,
958 From->getSourceRange().getBegin(), FromFunc, SourceLocation()) &&
959 !getLangOpts().CPlusPlus17;
960}
961
962bool Sema::CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New,
963 const CXXMethodDecl *Old) {
964 // If the new exception specification hasn't been parsed yet, skip the check.
965 // We'll get called again once it's been parsed.
966 if (New->getType()->castAs<FunctionProtoType>()->getExceptionSpecType() ==
967 EST_Unparsed)
968 return false;
969
970 // Don't check uninstantiated template destructors at all. We can only
971 // synthesize correct specs after the template is instantiated.
972 if (isa<CXXDestructorDecl>(New) && New->getParent()->isDependentType())
973 return false;
974
975 // If the old exception specification hasn't been parsed yet, or the new
976 // exception specification can't be computed yet, remember that we need to
977 // perform this check when we get to the end of the outermost
978 // lexically-surrounding class.
979 if (exceptionSpecNotKnownYet(Old) || exceptionSpecNotKnownYet(New)) {
980 DelayedOverridingExceptionSpecChecks.push_back({New, Old});
981 return false;
982 }
983
984 unsigned DiagID = diag::err_override_exception_spec;
985 if (getLangOpts().MSVCCompat)
986 DiagID = diag::ext_override_exception_spec;
987 return CheckExceptionSpecSubset(PDiag(DiagID),
988 PDiag(diag::err_deep_exception_specs_differ),
989 PDiag(diag::note_overridden_virtual_function),
990 PDiag(diag::ext_override_exception_spec),
991 Old->getType()->castAs<FunctionProtoType>(),
992 Old->getLocation(),
993 New->getType()->castAs<FunctionProtoType>(),
994 New->getLocation());
995}
996
997static CanThrowResult canSubStmtsThrow(Sema &Self, const Stmt *S) {
998 CanThrowResult R = CT_Cannot;
999 for (const Stmt *SubStmt : S->children()) {
1000 if (!SubStmt)
1001 continue;
1002 R = mergeCanThrow(R, Self.canThrow(SubStmt));
1003 if (R == CT_Can)
1004 break;
1005 }
1006 return R;
1007}
1008
1009CanThrowResult Sema::canCalleeThrow(Sema &S, const Expr *E, const Decl *D,
1010 SourceLocation Loc) {
1011 // As an extension, we assume that __attribute__((nothrow)) functions don't
1012 // throw.
1013 if (D && isa<FunctionDecl>(D) && D->hasAttr<NoThrowAttr>())
1014 return CT_Cannot;
1015
1016 QualType T;
1017
1018 // In C++1z, just look at the function type of the callee.
1019 if (S.getLangOpts().CPlusPlus17 && E && isa<CallExpr>(E)) {
1020 E = cast<CallExpr>(E)->getCallee();
1021 T = E->getType();
1022 if (T->isSpecificPlaceholderType(BuiltinType::BoundMember)) {
1023 // Sadly we don't preserve the actual type as part of the "bound member"
1024 // placeholder, so we need to reconstruct it.
1025 E = E->IgnoreParenImpCasts();
1026
1027 // Could be a call to a pointer-to-member or a plain member access.
1028 if (auto *Op = dyn_cast<BinaryOperator>(E)) {
1029 assert(Op->getOpcode() == BO_PtrMemD || Op->getOpcode() == BO_PtrMemI)(static_cast <bool> (Op->getOpcode() == BO_PtrMemD ||
Op->getOpcode() == BO_PtrMemI) ? void (0) : __assert_fail
("Op->getOpcode() == BO_PtrMemD || Op->getOpcode() == BO_PtrMemI"
, "clang/lib/Sema/SemaExceptionSpec.cpp", 1029, __extension__
__PRETTY_FUNCTION__))
;
1030 T = Op->getRHS()->getType()
1031 ->castAs<MemberPointerType>()->getPointeeType();
1032 } else {
1033 T = cast<MemberExpr>(E)->getMemberDecl()->getType();
1034 }
1035 }
1036 } else if (const ValueDecl *VD = dyn_cast_or_null<ValueDecl>(D))
1037 T = VD->getType();
1038 else
1039 // If we have no clue what we're calling, assume the worst.
1040 return CT_Can;
1041
1042 const FunctionProtoType *FT;
1043 if ((FT = T->getAs<FunctionProtoType>())) {
1044 } else if (const PointerType *PT = T->getAs<PointerType>())
1045 FT = PT->getPointeeType()->getAs<FunctionProtoType>();
1046 else if (const ReferenceType *RT = T->getAs<ReferenceType>())
1047 FT = RT->getPointeeType()->getAs<FunctionProtoType>();
1048 else if (const MemberPointerType *MT = T->getAs<MemberPointerType>())
1049 FT = MT->getPointeeType()->getAs<FunctionProtoType>();
1050 else if (const BlockPointerType *BT = T->getAs<BlockPointerType>())
1051 FT = BT->getPointeeType()->getAs<FunctionProtoType>();
1052
1053 if (!FT)
1054 return CT_Can;
1055
1056 if (Loc.isValid() || (Loc.isInvalid() && E))
1057 FT = S.ResolveExceptionSpec(Loc.isInvalid() ? E->getBeginLoc() : Loc, FT);
1058 if (!FT)
1059 return CT_Can;
1060
1061 return FT->canThrow();
1062}
1063
1064static CanThrowResult canVarDeclThrow(Sema &Self, const VarDecl *VD) {
1065 CanThrowResult CT = CT_Cannot;
1066
1067 // Initialization might throw.
1068 if (!VD->isUsableInConstantExpressions(Self.Context))
1069 if (const Expr *Init = VD->getInit())
1070 CT = mergeCanThrow(CT, Self.canThrow(Init));
1071
1072 // Destructor might throw.
1073 if (VD->needsDestruction(Self.Context) == QualType::DK_cxx_destructor) {
1074 if (auto *RD =
1075 VD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl()) {
1076 if (auto *Dtor = RD->getDestructor()) {
1077 CT = mergeCanThrow(
1078 CT, Sema::canCalleeThrow(Self, nullptr, Dtor, VD->getLocation()));
1079 }
1080 }
1081 }
1082
1083 // If this is a decomposition declaration, bindings might throw.
1084 if (auto *DD = dyn_cast<DecompositionDecl>(VD))
1085 for (auto *B : DD->bindings())
1086 if (auto *HD = B->getHoldingVar())
1087 CT = mergeCanThrow(CT, canVarDeclThrow(Self, HD));
1088
1089 return CT;
1090}
1091
1092static CanThrowResult canDynamicCastThrow(const CXXDynamicCastExpr *DC) {
1093 if (DC->isTypeDependent())
1094 return CT_Dependent;
1095
1096 if (!DC->getTypeAsWritten()->isReferenceType())
1097 return CT_Cannot;
1098
1099 if (DC->getSubExpr()->isTypeDependent())
1100 return CT_Dependent;
1101
1102 return DC->getCastKind() == clang::CK_Dynamic? CT_Can : CT_Cannot;
1103}
1104
1105static CanThrowResult canTypeidThrow(Sema &S, const CXXTypeidExpr *DC) {
1106 if (DC->isTypeOperand())
1107 return CT_Cannot;
1108
1109 Expr *Op = DC->getExprOperand();
1110 if (Op->isTypeDependent())
1111 return CT_Dependent;
1112
1113 const RecordType *RT = Op->getType()->getAs<RecordType>();
1114 if (!RT)
1115 return CT_Cannot;
1116
1117 if (!cast<CXXRecordDecl>(RT->getDecl())->isPolymorphic())
1118 return CT_Cannot;
1119
1120 if (Op->Classify(S.Context).isPRValue())
1121 return CT_Cannot;
1122
1123 return CT_Can;
1124}
1125
1126CanThrowResult Sema::canThrow(const Stmt *S) {
1127 // C++ [expr.unary.noexcept]p3:
1128 // [Can throw] if in a potentially-evaluated context the expression would
1129 // contain:
1130 switch (S->getStmtClass()) {
1131 case Expr::ConstantExprClass:
1132 return canThrow(cast<ConstantExpr>(S)->getSubExpr());
1133
1134 case Expr::CXXThrowExprClass:
1135 // - a potentially evaluated throw-expression
1136 return CT_Can;
1137
1138 case Expr::CXXDynamicCastExprClass: {
1139 // - a potentially evaluated dynamic_cast expression dynamic_cast<T>(v),
1140 // where T is a reference type, that requires a run-time check
1141 auto *CE = cast<CXXDynamicCastExpr>(S);
1142 // FIXME: Properly determine whether a variably-modified type can throw.
1143 if (CE->getType()->isVariablyModifiedType())
1144 return CT_Can;
1145 CanThrowResult CT = canDynamicCastThrow(CE);
1146 if (CT == CT_Can)
1147 return CT;
1148 return mergeCanThrow(CT, canSubStmtsThrow(*this, CE));
1149 }
1150
1151 case Expr::CXXTypeidExprClass:
1152 // - a potentially evaluated typeid expression applied to a glvalue
1153 // expression whose type is a polymorphic class type
1154 return canTypeidThrow(*this, cast<CXXTypeidExpr>(S));
1155
1156 // - a potentially evaluated call to a function, member function, function
1157 // pointer, or member function pointer that does not have a non-throwing
1158 // exception-specification
1159 case Expr::CallExprClass:
1160 case Expr::CXXMemberCallExprClass:
1161 case Expr::CXXOperatorCallExprClass:
1162 case Expr::UserDefinedLiteralClass: {
1163 const CallExpr *CE = cast<CallExpr>(S);
1164 CanThrowResult CT;
1165 if (CE->isTypeDependent())
1166 CT = CT_Dependent;
1167 else if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens()))
1168 CT = CT_Cannot;
1169 else
1170 CT = canCalleeThrow(*this, CE, CE->getCalleeDecl());
1171 if (CT == CT_Can)
1172 return CT;
1173 return mergeCanThrow(CT, canSubStmtsThrow(*this, CE));
1174 }
1175
1176 case Expr::CXXConstructExprClass:
1177 case Expr::CXXTemporaryObjectExprClass: {
1178 auto *CE = cast<CXXConstructExpr>(S);
1179 // FIXME: Properly determine whether a variably-modified type can throw.
1180 if (CE->getType()->isVariablyModifiedType())
1181 return CT_Can;
1182 CanThrowResult CT = canCalleeThrow(*this, CE, CE->getConstructor());
1183 if (CT == CT_Can)
1184 return CT;
1185 return mergeCanThrow(CT, canSubStmtsThrow(*this, CE));
1186 }
1187
1188 case Expr::CXXInheritedCtorInitExprClass: {
1189 auto *ICIE = cast<CXXInheritedCtorInitExpr>(S);
1190 return canCalleeThrow(*this, ICIE, ICIE->getConstructor());
1191 }
1192
1193 case Expr::LambdaExprClass: {
1194 const LambdaExpr *Lambda = cast<LambdaExpr>(S);
1195 CanThrowResult CT = CT_Cannot;
1196 for (LambdaExpr::const_capture_init_iterator
1197 Cap = Lambda->capture_init_begin(),
1198 CapEnd = Lambda->capture_init_end();
1199 Cap != CapEnd; ++Cap)
1200 CT = mergeCanThrow(CT, canThrow(*Cap));
1201 return CT;
1202 }
1203
1204 case Expr::CXXNewExprClass: {
1205 auto *NE = cast<CXXNewExpr>(S);
1206 CanThrowResult CT;
1207 if (NE->isTypeDependent())
1208 CT = CT_Dependent;
1209 else
1210 CT = canCalleeThrow(*this, NE, NE->getOperatorNew());
1211 if (CT == CT_Can)
1212 return CT;
1213 return mergeCanThrow(CT, canSubStmtsThrow(*this, NE));
1214 }
1215
1216 case Expr::CXXDeleteExprClass: {
1217 auto *DE = cast<CXXDeleteExpr>(S);
1218 CanThrowResult CT;
1219 QualType DTy = DE->getDestroyedType();
1220 if (DTy.isNull() || DTy->isDependentType()) {
1221 CT = CT_Dependent;
1222 } else {
1223 CT = canCalleeThrow(*this, DE, DE->getOperatorDelete());
1224 if (const RecordType *RT = DTy->getAs<RecordType>()) {
1225 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1226 const CXXDestructorDecl *DD = RD->getDestructor();
1227 if (DD)
1228 CT = mergeCanThrow(CT, canCalleeThrow(*this, DE, DD));
1229 }
1230 if (CT == CT_Can)
1231 return CT;
1232 }
1233 return mergeCanThrow(CT, canSubStmtsThrow(*this, DE));
1234 }
1235
1236 case Expr::CXXBindTemporaryExprClass: {
1237 auto *BTE = cast<CXXBindTemporaryExpr>(S);
1238 // The bound temporary has to be destroyed again, which might throw.
1239 CanThrowResult CT =
1240 canCalleeThrow(*this, BTE, BTE->getTemporary()->getDestructor());
1241 if (CT == CT_Can)
1242 return CT;
1243 return mergeCanThrow(CT, canSubStmtsThrow(*this, BTE));
1244 }
1245
1246 case Expr::PseudoObjectExprClass: {
1247 auto *POE = cast<PseudoObjectExpr>(S);
1248 CanThrowResult CT = CT_Cannot;
1249 for (const Expr *E : POE->semantics()) {
1250 CT = mergeCanThrow(CT, canThrow(E));
1251 if (CT == CT_Can)
1252 break;
1253 }
1254 return CT;
1255 }
1256
1257 // ObjC message sends are like function calls, but never have exception
1258 // specs.
1259 case Expr::ObjCMessageExprClass:
1260 case Expr::ObjCPropertyRefExprClass:
1261 case Expr::ObjCSubscriptRefExprClass:
1262 return CT_Can;
1263
1264 // All the ObjC literals that are implemented as calls are
1265 // potentially throwing unless we decide to close off that
1266 // possibility.
1267 case Expr::ObjCArrayLiteralClass:
1268 case Expr::ObjCDictionaryLiteralClass:
1269 case Expr::ObjCBoxedExprClass:
1270 return CT_Can;
1271
1272 // Many other things have subexpressions, so we have to test those.
1273 // Some are simple:
1274 case Expr::CoawaitExprClass:
1275 case Expr::ConditionalOperatorClass:
1276 case Expr::CoyieldExprClass:
1277 case Expr::CXXRewrittenBinaryOperatorClass:
1278 case Expr::CXXStdInitializerListExprClass:
1279 case Expr::DesignatedInitExprClass:
1280 case Expr::DesignatedInitUpdateExprClass:
1281 case Expr::ExprWithCleanupsClass:
1282 case Expr::ExtVectorElementExprClass:
1283 case Expr::InitListExprClass:
1284 case Expr::ArrayInitLoopExprClass:
1285 case Expr::MemberExprClass:
1286 case Expr::ObjCIsaExprClass:
1287 case Expr::ObjCIvarRefExprClass:
1288 case Expr::ParenExprClass:
1289 case Expr::ParenListExprClass:
1290 case Expr::ShuffleVectorExprClass:
1291 case Expr::StmtExprClass:
1292 case Expr::ConvertVectorExprClass:
1293 case Expr::VAArgExprClass:
1294 return canSubStmtsThrow(*this, S);
1295
1296 case Expr::CompoundLiteralExprClass:
1297 case Expr::CXXConstCastExprClass:
1298 case Expr::CXXAddrspaceCastExprClass:
1299 case Expr::CXXReinterpretCastExprClass:
1300 case Expr::BuiltinBitCastExprClass:
1301 // FIXME: Properly determine whether a variably-modified type can throw.
1302 if (cast<Expr>(S)->getType()->isVariablyModifiedType())
1303 return CT_Can;
1304 return canSubStmtsThrow(*this, S);
1305
1306 // Some might be dependent for other reasons.
1307 case Expr::ArraySubscriptExprClass:
1308 case Expr::MatrixSubscriptExprClass:
1309 case Expr::OMPArraySectionExprClass:
1310 case Expr::OMPArrayShapingExprClass:
1311 case Expr::OMPIteratorExprClass:
1312 case Expr::BinaryOperatorClass:
1313 case Expr::DependentCoawaitExprClass:
1314 case Expr::CompoundAssignOperatorClass:
1315 case Expr::CStyleCastExprClass:
1316 case Expr::CXXStaticCastExprClass:
1317 case Expr::CXXFunctionalCastExprClass:
1318 case Expr::ImplicitCastExprClass:
1319 case Expr::MaterializeTemporaryExprClass:
1320 case Expr::UnaryOperatorClass: {
1321 // FIXME: Properly determine whether a variably-modified type can throw.
1322 if (auto *CE = dyn_cast<CastExpr>(S))
1323 if (CE->getType()->isVariablyModifiedType())
1324 return CT_Can;
1325 CanThrowResult CT =
1326 cast<Expr>(S)->isTypeDependent() ? CT_Dependent : CT_Cannot;
1327 return mergeCanThrow(CT, canSubStmtsThrow(*this, S));
1328 }
1329
1330 case Expr::CXXDefaultArgExprClass:
1331 return canThrow(cast<CXXDefaultArgExpr>(S)->getExpr());
1332
1333 case Expr::CXXDefaultInitExprClass:
1334 return canThrow(cast<CXXDefaultInitExpr>(S)->getExpr());
1335
1336 case Expr::ChooseExprClass: {
1337 auto *CE = cast<ChooseExpr>(S);
1338 if (CE->isTypeDependent() || CE->isValueDependent())
1339 return CT_Dependent;
1340 return canThrow(CE->getChosenSubExpr());
1341 }
1342
1343 case Expr::GenericSelectionExprClass:
1344 if (cast<GenericSelectionExpr>(S)->isResultDependent())
1345 return CT_Dependent;
1346 return canThrow(cast<GenericSelectionExpr>(S)->getResultExpr());
1347
1348 // Some expressions are always dependent.
1349 case Expr::CXXDependentScopeMemberExprClass:
1350 case Expr::CXXUnresolvedConstructExprClass:
1351 case Expr::DependentScopeDeclRefExprClass:
1352 case Expr::CXXFoldExprClass:
1353 case Expr::RecoveryExprClass:
1354 return CT_Dependent;
1355
1356 case Expr::AsTypeExprClass:
1357 case Expr::BinaryConditionalOperatorClass:
1358 case Expr::BlockExprClass:
1359 case Expr::CUDAKernelCallExprClass:
1360 case Expr::DeclRefExprClass:
1361 case Expr::ObjCBridgedCastExprClass:
1362 case Expr::ObjCIndirectCopyRestoreExprClass:
1363 case Expr::ObjCProtocolExprClass:
1364 case Expr::ObjCSelectorExprClass:
1365 case Expr::ObjCAvailabilityCheckExprClass:
1366 case Expr::OffsetOfExprClass:
1367 case Expr::PackExpansionExprClass:
1368 case Expr::SubstNonTypeTemplateParmExprClass:
1369 case Expr::SubstNonTypeTemplateParmPackExprClass:
1370 case Expr::FunctionParmPackExprClass:
1371 case Expr::UnaryExprOrTypeTraitExprClass:
1372 case Expr::UnresolvedLookupExprClass:
1373 case Expr::UnresolvedMemberExprClass:
1374 case Expr::TypoExprClass:
1375 // FIXME: Many of the above can throw.
1376 return CT_Cannot;
1377
1378 case Expr::AddrLabelExprClass:
1379 case Expr::ArrayTypeTraitExprClass:
1380 case Expr::AtomicExprClass:
1381 case Expr::TypeTraitExprClass:
1382 case Expr::CXXBoolLiteralExprClass:
1383 case Expr::CXXNoexceptExprClass:
1384 case Expr::CXXNullPtrLiteralExprClass:
1385 case Expr::CXXPseudoDestructorExprClass:
1386 case Expr::CXXScalarValueInitExprClass:
1387 case Expr::CXXThisExprClass:
1388 case Expr::CXXUuidofExprClass:
1389 case Expr::CharacterLiteralClass:
1390 case Expr::ExpressionTraitExprClass:
1391 case Expr::FloatingLiteralClass:
1392 case Expr::GNUNullExprClass:
1393 case Expr::ImaginaryLiteralClass:
1394 case Expr::ImplicitValueInitExprClass:
1395 case Expr::IntegerLiteralClass:
1396 case Expr::FixedPointLiteralClass:
1397 case Expr::ArrayInitIndexExprClass:
1398 case Expr::NoInitExprClass:
1399 case Expr::ObjCEncodeExprClass:
1400 case Expr::ObjCStringLiteralClass:
1401 case Expr::ObjCBoolLiteralExprClass:
1402 case Expr::OpaqueValueExprClass:
1403 case Expr::PredefinedExprClass:
1404 case Expr::SizeOfPackExprClass:
1405 case Expr::StringLiteralClass:
1406 case Expr::SourceLocExprClass:
1407 case Expr::ConceptSpecializationExprClass:
1408 case Expr::RequiresExprClass:
1409 // These expressions can never throw.
1410 return CT_Cannot;
1411
1412 case Expr::MSPropertyRefExprClass:
1413 case Expr::MSPropertySubscriptExprClass:
1414 llvm_unreachable("Invalid class for expression")::llvm::llvm_unreachable_internal("Invalid class for expression"
, "clang/lib/Sema/SemaExceptionSpec.cpp", 1414)
;
1415
1416 // Most statements can throw if any substatement can throw.
1417 case Stmt::AttributedStmtClass:
1418 case Stmt::BreakStmtClass:
1419 case Stmt::CapturedStmtClass:
1420 case Stmt::CaseStmtClass:
1421 case Stmt::CompoundStmtClass:
1422 case Stmt::ContinueStmtClass:
1423 case Stmt::CoreturnStmtClass:
1424 case Stmt::CoroutineBodyStmtClass:
1425 case Stmt::CXXCatchStmtClass:
1426 case Stmt::CXXForRangeStmtClass:
1427 case Stmt::DefaultStmtClass:
1428 case Stmt::DoStmtClass:
1429 case Stmt::ForStmtClass:
1430 case Stmt::GCCAsmStmtClass:
1431 case Stmt::GotoStmtClass:
1432 case Stmt::IndirectGotoStmtClass:
1433 case Stmt::LabelStmtClass:
1434 case Stmt::MSAsmStmtClass:
1435 case Stmt::MSDependentExistsStmtClass:
1436 case Stmt::NullStmtClass:
1437 case Stmt::ObjCAtCatchStmtClass:
1438 case Stmt::ObjCAtFinallyStmtClass:
1439 case Stmt::ObjCAtSynchronizedStmtClass:
1440 case Stmt::ObjCAutoreleasePoolStmtClass:
1441 case Stmt::ObjCForCollectionStmtClass:
1442 case Stmt::OMPAtomicDirectiveClass:
1443 case Stmt::OMPBarrierDirectiveClass:
1444 case Stmt::OMPCancelDirectiveClass:
1445 case Stmt::OMPCancellationPointDirectiveClass:
1446 case Stmt::OMPCriticalDirectiveClass:
1447 case Stmt::OMPDistributeDirectiveClass:
1448 case Stmt::OMPDistributeParallelForDirectiveClass:
1449 case Stmt::OMPDistributeParallelForSimdDirectiveClass:
1450 case Stmt::OMPDistributeSimdDirectiveClass:
1451 case Stmt::OMPFlushDirectiveClass:
1452 case Stmt::OMPDepobjDirectiveClass:
1453 case Stmt::OMPScanDirectiveClass:
1454 case Stmt::OMPForDirectiveClass:
1455 case Stmt::OMPForSimdDirectiveClass:
1456 case Stmt::OMPMasterDirectiveClass:
1457 case Stmt::OMPMasterTaskLoopDirectiveClass:
1458 case Stmt::OMPMasterTaskLoopSimdDirectiveClass:
1459 case Stmt::OMPOrderedDirectiveClass:
1460 case Stmt::OMPCanonicalLoopClass:
1461 case Stmt::OMPParallelDirectiveClass:
1462 case Stmt::OMPParallelForDirectiveClass:
1463 case Stmt::OMPParallelForSimdDirectiveClass:
1464 case Stmt::OMPParallelMasterDirectiveClass:
1465 case Stmt::OMPParallelMasterTaskLoopDirectiveClass:
1466 case Stmt::OMPParallelMasterTaskLoopSimdDirectiveClass:
1467 case Stmt::OMPParallelSectionsDirectiveClass:
1468 case Stmt::OMPSectionDirectiveClass:
1469 case Stmt::OMPSectionsDirectiveClass:
1470 case Stmt::OMPSimdDirectiveClass:
1471 case Stmt::OMPTileDirectiveClass:
1472 case Stmt::OMPUnrollDirectiveClass:
1473 case Stmt::OMPSingleDirectiveClass:
1474 case Stmt::OMPTargetDataDirectiveClass:
1475 case Stmt::OMPTargetDirectiveClass:
1476 case Stmt::OMPTargetEnterDataDirectiveClass:
1477 case Stmt::OMPTargetExitDataDirectiveClass:
1478 case Stmt::OMPTargetParallelDirectiveClass:
1479 case Stmt::OMPTargetParallelForDirectiveClass:
1480 case Stmt::OMPTargetParallelForSimdDirectiveClass:
1481 case Stmt::OMPTargetSimdDirectiveClass:
1482 case Stmt::OMPTargetTeamsDirectiveClass:
1483 case Stmt::OMPTargetTeamsDistributeDirectiveClass:
1484 case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass:
1485 case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass:
1486 case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
1487 case Stmt::OMPTargetUpdateDirectiveClass:
1488 case Stmt::OMPTaskDirectiveClass:
1489 case Stmt::OMPTaskgroupDirectiveClass:
1490 case Stmt::OMPTaskLoopDirectiveClass:
1491 case Stmt::OMPTaskLoopSimdDirectiveClass:
1492 case Stmt::OMPTaskwaitDirectiveClass:
1493 case Stmt::OMPTaskyieldDirectiveClass:
1494 case Stmt::OMPTeamsDirectiveClass:
1495 case Stmt::OMPTeamsDistributeDirectiveClass:
1496 case Stmt::OMPTeamsDistributeParallelForDirectiveClass:
1497 case Stmt::OMPTeamsDistributeParallelForSimdDirectiveClass:
1498 case Stmt::OMPTeamsDistributeSimdDirectiveClass:
1499 case Stmt::OMPInteropDirectiveClass:
1500 case Stmt::OMPDispatchDirectiveClass:
1501 case Stmt::OMPMaskedDirectiveClass:
1502 case Stmt::OMPMetaDirectiveClass:
1503 case Stmt::OMPGenericLoopDirectiveClass:
1504 case Stmt::ReturnStmtClass:
1505 case Stmt::SEHExceptStmtClass:
1506 case Stmt::SEHFinallyStmtClass:
1507 case Stmt::SEHLeaveStmtClass:
1508 case Stmt::SEHTryStmtClass:
1509 case Stmt::SwitchStmtClass:
1510 case Stmt::WhileStmtClass:
1511 return canSubStmtsThrow(*this, S);
1512
1513 case Stmt::DeclStmtClass: {
1514 CanThrowResult CT = CT_Cannot;
1515 for (const Decl *D : cast<DeclStmt>(S)->decls()) {
1516 if (auto *VD = dyn_cast<VarDecl>(D))
1517 CT = mergeCanThrow(CT, canVarDeclThrow(*this, VD));
1518
1519 // FIXME: Properly determine whether a variably-modified type can throw.
1520 if (auto *TND = dyn_cast<TypedefNameDecl>(D))
1521 if (TND->getUnderlyingType()->isVariablyModifiedType())
1522 return CT_Can;
1523 if (auto *VD = dyn_cast<ValueDecl>(D))
1524 if (VD->getType()->isVariablyModifiedType())
1525 return CT_Can;
1526 }
1527 return CT;
1528 }
1529
1530 case Stmt::IfStmtClass: {
1531 auto *IS = cast<IfStmt>(S);
1532 CanThrowResult CT = CT_Cannot;
1533 if (const Stmt *Init = IS->getInit())
1534 CT = mergeCanThrow(CT, canThrow(Init));
1535 if (const Stmt *CondDS = IS->getConditionVariableDeclStmt())
1536 CT = mergeCanThrow(CT, canThrow(CondDS));
1537 CT = mergeCanThrow(CT, canThrow(IS->getCond()));
1538
1539 // For 'if constexpr', consider only the non-discarded case.
1540 // FIXME: We should add a DiscardedStmt marker to the AST.
1541 if (Optional<const Stmt *> Case = IS->getNondiscardedCase(Context))
1542 return *Case ? mergeCanThrow(CT, canThrow(*Case)) : CT;
1543
1544 CanThrowResult Then = canThrow(IS->getThen());
1545 CanThrowResult Else = IS->getElse() ? canThrow(IS->getElse()) : CT_Cannot;
1546 if (Then == Else)
1547 return mergeCanThrow(CT, Then);
1548
1549 // For a dependent 'if constexpr', the result is dependent if it depends on
1550 // the value of the condition.
1551 return mergeCanThrow(CT, IS->isConstexpr() ? CT_Dependent
1552 : mergeCanThrow(Then, Else));
1553 }
1554
1555 case Stmt::CXXTryStmtClass: {
1556 auto *TS = cast<CXXTryStmt>(S);
1557 // try /*...*/ catch (...) { H } can throw only if H can throw.
1558 // Any other try-catch can throw if any substatement can throw.
1559 const CXXCatchStmt *FinalHandler = TS->getHandler(TS->getNumHandlers() - 1);
1560 if (!FinalHandler->getExceptionDecl())
1561 return canThrow(FinalHandler->getHandlerBlock());
1562 return canSubStmtsThrow(*this, S);
1563 }
1564
1565 case Stmt::ObjCAtThrowStmtClass:
1566 return CT_Can;
1567
1568 case Stmt::ObjCAtTryStmtClass: {
1569 auto *TS = cast<ObjCAtTryStmt>(S);
1570
1571 // @catch(...) need not be last in Objective-C. Walk backwards until we
1572 // see one or hit the @try.
1573 CanThrowResult CT = CT_Cannot;
1574 if (const Stmt *Finally = TS->getFinallyStmt())
1575 CT = mergeCanThrow(CT, canThrow(Finally));
1576 for (unsigned I = TS->getNumCatchStmts(); I != 0; --I) {
1577 const ObjCAtCatchStmt *Catch = TS->getCatchStmt(I - 1);
1578 CT = mergeCanThrow(CT, canThrow(Catch));
1579 // If we reach a @catch(...), no earlier exceptions can escape.
1580 if (Catch->hasEllipsis())
1581 return CT;
1582 }
1583
1584 // Didn't find an @catch(...). Exceptions from the @try body can escape.
1585 return mergeCanThrow(CT, canThrow(TS->getTryBody()));
1586 }
1587
1588 case Stmt::SYCLUniqueStableNameExprClass:
1589 return CT_Cannot;
1590 case Stmt::NoStmtClass:
1591 llvm_unreachable("Invalid class for statement")::llvm::llvm_unreachable_internal("Invalid class for statement"
, "clang/lib/Sema/SemaExceptionSpec.cpp", 1591)
;
1592 }
1593 llvm_unreachable("Bogus StmtClass")::llvm::llvm_unreachable_internal("Bogus StmtClass", "clang/lib/Sema/SemaExceptionSpec.cpp"
, 1593)
;
1594}
1595
1596} // end namespace clang