Bug Summary

File:tools/clang/lib/Sema/SemaTemplateVariadic.cpp
Warning:line 670, column 11
Called C++ object pointer is null

Annotated Source Code

[?] Use j/k keys for keyboard navigation

1//===------- SemaTemplateVariadic.cpp - C++ Variadic Templates ------------===/
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//===----------------------------------------------------------------------===/
8//
9// This file implements semantic analysis for C++0x variadic templates.
10//===----------------------------------------------------------------------===/
11
12#include "clang/Sema/Sema.h"
13#include "TypeLocBuilder.h"
14#include "clang/AST/Expr.h"
15#include "clang/AST/RecursiveASTVisitor.h"
16#include "clang/AST/TypeLoc.h"
17#include "clang/Sema/Lookup.h"
18#include "clang/Sema/ParsedTemplate.h"
19#include "clang/Sema/ScopeInfo.h"
20#include "clang/Sema/SemaInternal.h"
21#include "clang/Sema/Template.h"
22
23using namespace clang;
24
25//----------------------------------------------------------------------------
26// Visitor that collects unexpanded parameter packs
27//----------------------------------------------------------------------------
28
29/// \brief Retrieve the depth and index of a parameter pack.
30static std::pair<unsigned, unsigned>
31getDepthAndIndex(NamedDecl *ND) {
32 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ND))
33 return std::make_pair(TTP->getDepth(), TTP->getIndex());
34
35 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(ND))
36 return std::make_pair(NTTP->getDepth(), NTTP->getIndex());
37
38 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(ND);
39 return std::make_pair(TTP->getDepth(), TTP->getIndex());
40}
41
42namespace {
43 /// \brief A class that collects unexpanded parameter packs.
44 class CollectUnexpandedParameterPacksVisitor :
45 public RecursiveASTVisitor<CollectUnexpandedParameterPacksVisitor>
46 {
47 typedef RecursiveASTVisitor<CollectUnexpandedParameterPacksVisitor>
48 inherited;
49
50 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded;
51
52 bool InLambda = false;
53 unsigned DepthLimit = (unsigned)-1;
54
55 void addUnexpanded(NamedDecl *ND, SourceLocation Loc = SourceLocation()) {
56 if (auto *PVD = dyn_cast<ParmVarDecl>(ND)) {
57 // For now, the only problematic case is a generic lambda's templated
58 // call operator, so we don't need to look for all the other ways we
59 // could have reached a dependent parameter pack.
60 auto *FD = dyn_cast<FunctionDecl>(PVD->getDeclContext());
61 auto *FTD = FD ? FD->getDescribedFunctionTemplate() : nullptr;
62 if (FTD && FTD->getTemplateParameters()->getDepth() >= DepthLimit)
63 return;
64 } else if (getDepthAndIndex(ND).first >= DepthLimit)
65 return;
66
67 Unexpanded.push_back({ND, Loc});
68 }
69 void addUnexpanded(const TemplateTypeParmType *T,
70 SourceLocation Loc = SourceLocation()) {
71 if (T->getDepth() < DepthLimit)
72 Unexpanded.push_back({T, Loc});
73 }
74
75 public:
76 explicit CollectUnexpandedParameterPacksVisitor(
77 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded)
78 : Unexpanded(Unexpanded) {}
79
80 bool shouldWalkTypesOfTypeLocs() const { return false; }
81
82 //------------------------------------------------------------------------
83 // Recording occurrences of (unexpanded) parameter packs.
84 //------------------------------------------------------------------------
85
86 /// \brief Record occurrences of template type parameter packs.
87 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
88 if (TL.getTypePtr()->isParameterPack())
89 addUnexpanded(TL.getTypePtr(), TL.getNameLoc());
90 return true;
91 }
92
93 /// \brief Record occurrences of template type parameter packs
94 /// when we don't have proper source-location information for
95 /// them.
96 ///
97 /// Ideally, this routine would never be used.
98 bool VisitTemplateTypeParmType(TemplateTypeParmType *T) {
99 if (T->isParameterPack())
100 addUnexpanded(T);
101
102 return true;
103 }
104
105 /// \brief Record occurrences of function and non-type template
106 /// parameter packs in an expression.
107 bool VisitDeclRefExpr(DeclRefExpr *E) {
108 if (E->getDecl()->isParameterPack())
109 addUnexpanded(E->getDecl(), E->getLocation());
110
111 return true;
112 }
113
114 /// \brief Record occurrences of template template parameter packs.
115 bool TraverseTemplateName(TemplateName Template) {
116 if (auto *TTP = dyn_cast_or_null<TemplateTemplateParmDecl>(
117 Template.getAsTemplateDecl())) {
118 if (TTP->isParameterPack())
119 addUnexpanded(TTP);
120 }
121
122 return inherited::TraverseTemplateName(Template);
123 }
124
125 /// \brief Suppress traversal into Objective-C container literal
126 /// elements that are pack expansions.
127 bool TraverseObjCDictionaryLiteral(ObjCDictionaryLiteral *E) {
128 if (!E->containsUnexpandedParameterPack())
129 return true;
130
131 for (unsigned I = 0, N = E->getNumElements(); I != N; ++I) {
132 ObjCDictionaryElement Element = E->getKeyValueElement(I);
133 if (Element.isPackExpansion())
134 continue;
135
136 TraverseStmt(Element.Key);
137 TraverseStmt(Element.Value);
138 }
139 return true;
140 }
141 //------------------------------------------------------------------------
142 // Pruning the search for unexpanded parameter packs.
143 //------------------------------------------------------------------------
144
145 /// \brief Suppress traversal into statements and expressions that
146 /// do not contain unexpanded parameter packs.
147 bool TraverseStmt(Stmt *S) {
148 Expr *E = dyn_cast_or_null<Expr>(S);
149 if ((E && E->containsUnexpandedParameterPack()) || InLambda)
150 return inherited::TraverseStmt(S);
151
152 return true;
153 }
154
155 /// \brief Suppress traversal into types that do not contain
156 /// unexpanded parameter packs.
157 bool TraverseType(QualType T) {
158 if ((!T.isNull() && T->containsUnexpandedParameterPack()) || InLambda)
159 return inherited::TraverseType(T);
160
161 return true;
162 }
163
164 /// \brief Suppress traversal into types with location information
165 /// that do not contain unexpanded parameter packs.
166 bool TraverseTypeLoc(TypeLoc TL) {
167 if ((!TL.getType().isNull() &&
168 TL.getType()->containsUnexpandedParameterPack()) ||
169 InLambda)
170 return inherited::TraverseTypeLoc(TL);
171
172 return true;
173 }
174
175 /// \brief Suppress traversal of parameter packs.
176 bool TraverseDecl(Decl *D) {
177 // A function parameter pack is a pack expansion, so cannot contain
178 // an unexpanded parameter pack. Likewise for a template parameter
179 // pack that contains any references to other packs.
180 if (D->isParameterPack())
181 return true;
182
183 return inherited::TraverseDecl(D);
184 }
185
186 /// \brief Suppress traversal of pack-expanded attributes.
187 bool TraverseAttr(Attr *A) {
188 if (A->isPackExpansion())
189 return true;
190
191 return inherited::TraverseAttr(A);
192 }
193
194 /// \brief Suppress traversal of pack expansion expressions and types.
195 ///@{
196 bool TraversePackExpansionType(PackExpansionType *T) { return true; }
197 bool TraversePackExpansionTypeLoc(PackExpansionTypeLoc TL) { return true; }
198 bool TraversePackExpansionExpr(PackExpansionExpr *E) { return true; }
199 bool TraverseCXXFoldExpr(CXXFoldExpr *E) { return true; }
200
201 ///@}
202
203 /// \brief Suppress traversal of using-declaration pack expansion.
204 bool TraverseUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
205 if (D->isPackExpansion())
206 return true;
207
208 return inherited::TraverseUnresolvedUsingValueDecl(D);
209 }
210
211 /// \brief Suppress traversal of using-declaration pack expansion.
212 bool TraverseUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
213 if (D->isPackExpansion())
214 return true;
215
216 return inherited::TraverseUnresolvedUsingTypenameDecl(D);
217 }
218
219 /// \brief Suppress traversal of template argument pack expansions.
220 bool TraverseTemplateArgument(const TemplateArgument &Arg) {
221 if (Arg.isPackExpansion())
222 return true;
223
224 return inherited::TraverseTemplateArgument(Arg);
225 }
226
227 /// \brief Suppress traversal of template argument pack expansions.
228 bool TraverseTemplateArgumentLoc(const TemplateArgumentLoc &ArgLoc) {
229 if (ArgLoc.getArgument().isPackExpansion())
230 return true;
231
232 return inherited::TraverseTemplateArgumentLoc(ArgLoc);
233 }
234
235 /// \brief Suppress traversal of base specifier pack expansions.
236 bool TraverseCXXBaseSpecifier(const CXXBaseSpecifier &Base) {
237 if (Base.isPackExpansion())
238 return true;
239
240 return inherited::TraverseCXXBaseSpecifier(Base);
241 }
242
243 /// \brief Suppress traversal of mem-initializer pack expansions.
244 bool TraverseConstructorInitializer(CXXCtorInitializer *Init) {
245 if (Init->isPackExpansion())
246 return true;
247
248 return inherited::TraverseConstructorInitializer(Init);
249 }
250
251 /// \brief Note whether we're traversing a lambda containing an unexpanded
252 /// parameter pack. In this case, the unexpanded pack can occur anywhere,
253 /// including all the places where we normally wouldn't look. Within a
254 /// lambda, we don't propagate the 'contains unexpanded parameter pack' bit
255 /// outside an expression.
256 bool TraverseLambdaExpr(LambdaExpr *Lambda) {
257 // The ContainsUnexpandedParameterPack bit on a lambda is always correct,
258 // even if it's contained within another lambda.
259 if (!Lambda->containsUnexpandedParameterPack())
260 return true;
261
262 bool WasInLambda = InLambda;
263 unsigned OldDepthLimit = DepthLimit;
264
265 InLambda = true;
266 if (auto *TPL = Lambda->getTemplateParameterList())
267 DepthLimit = TPL->getDepth();
268
269 inherited::TraverseLambdaExpr(Lambda);
270
271 InLambda = WasInLambda;
272 DepthLimit = OldDepthLimit;
273 return true;
274 }
275
276 /// Suppress traversal within pack expansions in lambda captures.
277 bool TraverseLambdaCapture(LambdaExpr *Lambda, const LambdaCapture *C,
278 Expr *Init) {
279 if (C->isPackExpansion())
280 return true;
281
282 return inherited::TraverseLambdaCapture(Lambda, C, Init);
283 }
284 };
285}
286
287/// \brief Determine whether it's possible for an unexpanded parameter pack to
288/// be valid in this location. This only happens when we're in a declaration
289/// that is nested within an expression that could be expanded, such as a
290/// lambda-expression within a function call.
291///
292/// This is conservatively correct, but may claim that some unexpanded packs are
293/// permitted when they are not.
294bool Sema::isUnexpandedParameterPackPermitted() {
295 for (auto *SI : FunctionScopes)
296 if (isa<sema::LambdaScopeInfo>(SI))
297 return true;
298 return false;
299}
300
301/// \brief Diagnose all of the unexpanded parameter packs in the given
302/// vector.
303bool
304Sema::DiagnoseUnexpandedParameterPacks(SourceLocation Loc,
305 UnexpandedParameterPackContext UPPC,
306 ArrayRef<UnexpandedParameterPack> Unexpanded) {
307 if (Unexpanded.empty())
308 return false;
309
310 // If we are within a lambda expression and referencing a pack that is not
311 // a parameter of the lambda itself, that lambda contains an unexpanded
312 // parameter pack, and we are done.
313 // FIXME: Store 'Unexpanded' on the lambda so we don't need to recompute it
314 // later.
315 SmallVector<UnexpandedParameterPack, 4> LambdaParamPackReferences;
316 for (unsigned N = FunctionScopes.size(); N; --N) {
317 if (sema::LambdaScopeInfo *LSI =
318 dyn_cast<sema::LambdaScopeInfo>(FunctionScopes[N-1])) {
319 if (N == FunctionScopes.size()) {
320 for (auto &Param : Unexpanded) {
321 auto *PD = dyn_cast_or_null<ParmVarDecl>(
322 Param.first.dyn_cast<NamedDecl *>());
323 if (PD && PD->getDeclContext() == LSI->CallOperator)
324 LambdaParamPackReferences.push_back(Param);
325 }
326 }
327
328 // If we have references to a parameter pack of the innermost enclosing
329 // lambda, only diagnose those ones. We don't know whether any other
330 // unexpanded parameters referenced herein are actually unexpanded;
331 // they might be expanded at an outer level.
332 if (!LambdaParamPackReferences.empty()) {
333 Unexpanded = LambdaParamPackReferences;
334 break;
335 }
336
337 LSI->ContainsUnexpandedParameterPack = true;
338 return false;
339 }
340 }
341
342 SmallVector<SourceLocation, 4> Locations;
343 SmallVector<IdentifierInfo *, 4> Names;
344 llvm::SmallPtrSet<IdentifierInfo *, 4> NamesKnown;
345
346 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
347 IdentifierInfo *Name = nullptr;
348 if (const TemplateTypeParmType *TTP
349 = Unexpanded[I].first.dyn_cast<const TemplateTypeParmType *>())
350 Name = TTP->getIdentifier();
351 else
352 Name = Unexpanded[I].first.get<NamedDecl *>()->getIdentifier();
353
354 if (Name && NamesKnown.insert(Name).second)
355 Names.push_back(Name);
356
357 if (Unexpanded[I].second.isValid())
358 Locations.push_back(Unexpanded[I].second);
359 }
360
361 DiagnosticBuilder DB = Diag(Loc, diag::err_unexpanded_parameter_pack)
362 << (int)UPPC << (int)Names.size();
363 for (size_t I = 0, E = std::min(Names.size(), (size_t)2); I != E; ++I)
364 DB << Names[I];
365
366 for (unsigned I = 0, N = Locations.size(); I != N; ++I)
367 DB << SourceRange(Locations[I]);
368 return true;
369}
370
371bool Sema::DiagnoseUnexpandedParameterPack(SourceLocation Loc,
372 TypeSourceInfo *T,
373 UnexpandedParameterPackContext UPPC) {
374 // C++0x [temp.variadic]p5:
375 // An appearance of a name of a parameter pack that is not expanded is
376 // ill-formed.
377 if (!T->getType()->containsUnexpandedParameterPack())
378 return false;
379
380 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
381 CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseTypeLoc(
382 T->getTypeLoc());
383 assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs")(static_cast <bool> (!Unexpanded.empty() && "Unable to find unexpanded parameter packs"
) ? void (0) : __assert_fail ("!Unexpanded.empty() && \"Unable to find unexpanded parameter packs\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 383, __extension__ __PRETTY_FUNCTION__))
;
384 return DiagnoseUnexpandedParameterPacks(Loc, UPPC, Unexpanded);
385}
386
387bool Sema::DiagnoseUnexpandedParameterPack(Expr *E,
388 UnexpandedParameterPackContext UPPC) {
389 // C++0x [temp.variadic]p5:
390 // An appearance of a name of a parameter pack that is not expanded is
391 // ill-formed.
392 if (!E->containsUnexpandedParameterPack())
393 return false;
394
395 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
396 CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseStmt(E);
397 assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs")(static_cast <bool> (!Unexpanded.empty() && "Unable to find unexpanded parameter packs"
) ? void (0) : __assert_fail ("!Unexpanded.empty() && \"Unable to find unexpanded parameter packs\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 397, __extension__ __PRETTY_FUNCTION__))
;
398 return DiagnoseUnexpandedParameterPacks(E->getLocStart(), UPPC, Unexpanded);
399}
400
401bool Sema::DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS,
402 UnexpandedParameterPackContext UPPC) {
403 // C++0x [temp.variadic]p5:
404 // An appearance of a name of a parameter pack that is not expanded is
405 // ill-formed.
406 if (!SS.getScopeRep() ||
407 !SS.getScopeRep()->containsUnexpandedParameterPack())
408 return false;
409
410 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
411 CollectUnexpandedParameterPacksVisitor(Unexpanded)
412 .TraverseNestedNameSpecifier(SS.getScopeRep());
413 assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs")(static_cast <bool> (!Unexpanded.empty() && "Unable to find unexpanded parameter packs"
) ? void (0) : __assert_fail ("!Unexpanded.empty() && \"Unable to find unexpanded parameter packs\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 413, __extension__ __PRETTY_FUNCTION__))
;
414 return DiagnoseUnexpandedParameterPacks(SS.getRange().getBegin(),
415 UPPC, Unexpanded);
416}
417
418bool Sema::DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo,
419 UnexpandedParameterPackContext UPPC) {
420 // C++0x [temp.variadic]p5:
421 // An appearance of a name of a parameter pack that is not expanded is
422 // ill-formed.
423 switch (NameInfo.getName().getNameKind()) {
424 case DeclarationName::Identifier:
425 case DeclarationName::ObjCZeroArgSelector:
426 case DeclarationName::ObjCOneArgSelector:
427 case DeclarationName::ObjCMultiArgSelector:
428 case DeclarationName::CXXOperatorName:
429 case DeclarationName::CXXLiteralOperatorName:
430 case DeclarationName::CXXUsingDirective:
431 case DeclarationName::CXXDeductionGuideName:
432 return false;
433
434 case DeclarationName::CXXConstructorName:
435 case DeclarationName::CXXDestructorName:
436 case DeclarationName::CXXConversionFunctionName:
437 // FIXME: We shouldn't need this null check!
438 if (TypeSourceInfo *TSInfo = NameInfo.getNamedTypeInfo())
439 return DiagnoseUnexpandedParameterPack(NameInfo.getLoc(), TSInfo, UPPC);
440
441 if (!NameInfo.getName().getCXXNameType()->containsUnexpandedParameterPack())
442 return false;
443
444 break;
445 }
446
447 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
448 CollectUnexpandedParameterPacksVisitor(Unexpanded)
449 .TraverseType(NameInfo.getName().getCXXNameType());
450 assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs")(static_cast <bool> (!Unexpanded.empty() && "Unable to find unexpanded parameter packs"
) ? void (0) : __assert_fail ("!Unexpanded.empty() && \"Unable to find unexpanded parameter packs\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 450, __extension__ __PRETTY_FUNCTION__))
;
451 return DiagnoseUnexpandedParameterPacks(NameInfo.getLoc(), UPPC, Unexpanded);
452}
453
454bool Sema::DiagnoseUnexpandedParameterPack(SourceLocation Loc,
455 TemplateName Template,
456 UnexpandedParameterPackContext UPPC) {
457
458 if (Template.isNull() || !Template.containsUnexpandedParameterPack())
459 return false;
460
461 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
462 CollectUnexpandedParameterPacksVisitor(Unexpanded)
463 .TraverseTemplateName(Template);
464 assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs")(static_cast <bool> (!Unexpanded.empty() && "Unable to find unexpanded parameter packs"
) ? void (0) : __assert_fail ("!Unexpanded.empty() && \"Unable to find unexpanded parameter packs\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 464, __extension__ __PRETTY_FUNCTION__))
;
465 return DiagnoseUnexpandedParameterPacks(Loc, UPPC, Unexpanded);
466}
467
468bool Sema::DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg,
469 UnexpandedParameterPackContext UPPC) {
470 if (Arg.getArgument().isNull() ||
471 !Arg.getArgument().containsUnexpandedParameterPack())
472 return false;
473
474 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
475 CollectUnexpandedParameterPacksVisitor(Unexpanded)
476 .TraverseTemplateArgumentLoc(Arg);
477 assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs")(static_cast <bool> (!Unexpanded.empty() && "Unable to find unexpanded parameter packs"
) ? void (0) : __assert_fail ("!Unexpanded.empty() && \"Unable to find unexpanded parameter packs\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 477, __extension__ __PRETTY_FUNCTION__))
;
478 return DiagnoseUnexpandedParameterPacks(Arg.getLocation(), UPPC, Unexpanded);
479}
480
481void Sema::collectUnexpandedParameterPacks(TemplateArgument Arg,
482 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
483 CollectUnexpandedParameterPacksVisitor(Unexpanded)
484 .TraverseTemplateArgument(Arg);
485}
486
487void Sema::collectUnexpandedParameterPacks(TemplateArgumentLoc Arg,
488 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
489 CollectUnexpandedParameterPacksVisitor(Unexpanded)
490 .TraverseTemplateArgumentLoc(Arg);
491}
492
493void Sema::collectUnexpandedParameterPacks(QualType T,
494 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
495 CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseType(T);
496}
497
498void Sema::collectUnexpandedParameterPacks(TypeLoc TL,
499 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
500 CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseTypeLoc(TL);
501}
502
503void Sema::collectUnexpandedParameterPacks(
504 NestedNameSpecifierLoc NNS,
505 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
506 CollectUnexpandedParameterPacksVisitor(Unexpanded)
507 .TraverseNestedNameSpecifierLoc(NNS);
508}
509
510void Sema::collectUnexpandedParameterPacks(
511 const DeclarationNameInfo &NameInfo,
512 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
513 CollectUnexpandedParameterPacksVisitor(Unexpanded)
514 .TraverseDeclarationNameInfo(NameInfo);
515}
516
517
518ParsedTemplateArgument
519Sema::ActOnPackExpansion(const ParsedTemplateArgument &Arg,
520 SourceLocation EllipsisLoc) {
521 if (Arg.isInvalid())
522 return Arg;
523
524 switch (Arg.getKind()) {
525 case ParsedTemplateArgument::Type: {
526 TypeResult Result = ActOnPackExpansion(Arg.getAsType(), EllipsisLoc);
527 if (Result.isInvalid())
528 return ParsedTemplateArgument();
529
530 return ParsedTemplateArgument(Arg.getKind(), Result.get().getAsOpaquePtr(),
531 Arg.getLocation());
532 }
533
534 case ParsedTemplateArgument::NonType: {
535 ExprResult Result = ActOnPackExpansion(Arg.getAsExpr(), EllipsisLoc);
536 if (Result.isInvalid())
537 return ParsedTemplateArgument();
538
539 return ParsedTemplateArgument(Arg.getKind(), Result.get(),
540 Arg.getLocation());
541 }
542
543 case ParsedTemplateArgument::Template:
544 if (!Arg.getAsTemplate().get().containsUnexpandedParameterPack()) {
545 SourceRange R(Arg.getLocation());
546 if (Arg.getScopeSpec().isValid())
547 R.setBegin(Arg.getScopeSpec().getBeginLoc());
548 Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
549 << R;
550 return ParsedTemplateArgument();
551 }
552
553 return Arg.getTemplatePackExpansion(EllipsisLoc);
554 }
555 llvm_unreachable("Unhandled template argument kind?")::llvm::llvm_unreachable_internal("Unhandled template argument kind?"
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 555)
;
556}
557
558TypeResult Sema::ActOnPackExpansion(ParsedType Type,
559 SourceLocation EllipsisLoc) {
560 TypeSourceInfo *TSInfo;
561 GetTypeFromParser(Type, &TSInfo);
562 if (!TSInfo)
563 return true;
564
565 TypeSourceInfo *TSResult = CheckPackExpansion(TSInfo, EllipsisLoc, None);
566 if (!TSResult)
567 return true;
568
569 return CreateParsedType(TSResult->getType(), TSResult);
570}
571
572TypeSourceInfo *
573Sema::CheckPackExpansion(TypeSourceInfo *Pattern, SourceLocation EllipsisLoc,
574 Optional<unsigned> NumExpansions) {
575 // Create the pack expansion type and source-location information.
576 QualType Result = CheckPackExpansion(Pattern->getType(),
577 Pattern->getTypeLoc().getSourceRange(),
578 EllipsisLoc, NumExpansions);
579 if (Result.isNull())
580 return nullptr;
581
582 TypeLocBuilder TLB;
583 TLB.pushFullCopy(Pattern->getTypeLoc());
584 PackExpansionTypeLoc TL = TLB.push<PackExpansionTypeLoc>(Result);
585 TL.setEllipsisLoc(EllipsisLoc);
586
587 return TLB.getTypeSourceInfo(Context, Result);
588}
589
590QualType Sema::CheckPackExpansion(QualType Pattern, SourceRange PatternRange,
591 SourceLocation EllipsisLoc,
592 Optional<unsigned> NumExpansions) {
593 // C++0x [temp.variadic]p5:
594 // The pattern of a pack expansion shall name one or more
595 // parameter packs that are not expanded by a nested pack
596 // expansion.
597 if (!Pattern->containsUnexpandedParameterPack()) {
598 Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
599 << PatternRange;
600 return QualType();
601 }
602
603 return Context.getPackExpansionType(Pattern, NumExpansions);
604}
605
606ExprResult Sema::ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc) {
607 return CheckPackExpansion(Pattern, EllipsisLoc, None);
608}
609
610ExprResult Sema::CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
611 Optional<unsigned> NumExpansions) {
612 if (!Pattern)
613 return ExprError();
614
615 // C++0x [temp.variadic]p5:
616 // The pattern of a pack expansion shall name one or more
617 // parameter packs that are not expanded by a nested pack
618 // expansion.
619 if (!Pattern->containsUnexpandedParameterPack()) {
620 Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
621 << Pattern->getSourceRange();
622 return ExprError();
623 }
624
625 // Create the pack expansion expression and source-location information.
626 return new (Context)
627 PackExpansionExpr(Context.DependentTy, Pattern, EllipsisLoc, NumExpansions);
628}
629
630bool Sema::CheckParameterPacksForExpansion(
631 SourceLocation EllipsisLoc, SourceRange PatternRange,
632 ArrayRef<UnexpandedParameterPack> Unexpanded,
633 const MultiLevelTemplateArgumentList &TemplateArgs, bool &ShouldExpand,
634 bool &RetainExpansion, Optional<unsigned> &NumExpansions) {
635 ShouldExpand = true;
636 RetainExpansion = false;
637 std::pair<IdentifierInfo *, SourceLocation> FirstPack;
638 bool HaveFirstPack = false;
639
640 for (ArrayRef<UnexpandedParameterPack>::iterator i = Unexpanded.begin(),
2
Loop condition is true. Entering loop body
13
Loop condition is true. Entering loop body
19
Loop condition is true. Entering loop body
641 end = Unexpanded.end();
642 i != end; ++i) {
1
Assuming 'i' is not equal to 'end'
643 // Compute the depth and index for this parameter pack.
644 unsigned Depth = 0, Index = 0;
645 IdentifierInfo *Name;
646 bool IsFunctionParameterPack = false;
647
648 if (const TemplateTypeParmType *TTP
3
Taking false branch
14
Taking false branch
20
Taking false branch
649 = i->first.dyn_cast<const TemplateTypeParmType *>()) {
650 Depth = TTP->getDepth();
651 Index = TTP->getIndex();
652 Name = TTP->getIdentifier();
653 } else {
654 NamedDecl *ND = i->first.get<NamedDecl *>();
655 if (isa<ParmVarDecl>(ND))
4
Taking false branch
15
Taking false branch
21
Taking true branch
656 IsFunctionParameterPack = true;
657 else
658 std::tie(Depth, Index) = getDepthAndIndex(ND);
659
660 Name = ND->getIdentifier();
661 }
662
663 // Determine the size of this argument pack.
664 unsigned NewPackSize;
665 if (IsFunctionParameterPack) {
5
Taking false branch
16
Taking false branch
22
Taking true branch
666 // Figure out whether we're instantiating to an argument pack or not.
667 typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
668
669 llvm::PointerUnion<Decl *, DeclArgumentPack *> *Instantiation
670 = CurrentInstantiationScope->findInstantiationOf(
23
Called C++ object pointer is null
671 i->first.get<NamedDecl *>());
672 if (Instantiation->is<DeclArgumentPack *>()) {
673 // We could expand this function parameter pack.
674 NewPackSize = Instantiation->get<DeclArgumentPack *>()->size();
675 } else {
676 // We can't expand this function parameter pack, so we can't expand
677 // the pack expansion.
678 ShouldExpand = false;
679 continue;
680 }
681 } else {
682 // If we don't have a template argument at this depth/index, then we
683 // cannot expand the pack expansion. Make a note of this, but we still
684 // want to check any parameter packs we *do* have arguments for.
685 if (Depth >= TemplateArgs.getNumLevels() ||
6
Taking false branch
17
Taking true branch
686 !TemplateArgs.hasTemplateArgument(Depth, Index)) {
687 ShouldExpand = false;
688 continue;
18
Execution continues on line 642
689 }
690
691 // Determine the size of the argument pack.
692 NewPackSize = TemplateArgs(Depth, Index).pack_size();
693 }
694
695 // C++0x [temp.arg.explicit]p9:
696 // Template argument deduction can extend the sequence of template
697 // arguments corresponding to a template parameter pack, even when the
698 // sequence contains explicitly specified template arguments.
699 if (!IsFunctionParameterPack && CurrentInstantiationScope) {
7
Assuming the condition is false
8
Assuming pointer value is null
9
Taking false branch
700 if (NamedDecl *PartialPack
701 = CurrentInstantiationScope->getPartiallySubstitutedPack()){
702 unsigned PartialDepth, PartialIndex;
703 std::tie(PartialDepth, PartialIndex) = getDepthAndIndex(PartialPack);
704 if (PartialDepth == Depth && PartialIndex == Index)
705 RetainExpansion = true;
706 }
707 }
708
709 if (!NumExpansions) {
10
Assuming the condition is false
11
Taking false branch
710 // The is the first pack we've seen for which we have an argument.
711 // Record it.
712 NumExpansions = NewPackSize;
713 FirstPack.first = Name;
714 FirstPack.second = i->second;
715 HaveFirstPack = true;
716 continue;
717 }
718
719 if (NewPackSize != *NumExpansions) {
12
Taking false branch
720 // C++0x [temp.variadic]p5:
721 // All of the parameter packs expanded by a pack expansion shall have
722 // the same number of arguments specified.
723 if (HaveFirstPack)
724 Diag(EllipsisLoc, diag::err_pack_expansion_length_conflict)
725 << FirstPack.first << Name << *NumExpansions << NewPackSize
726 << SourceRange(FirstPack.second) << SourceRange(i->second);
727 else
728 Diag(EllipsisLoc, diag::err_pack_expansion_length_conflict_multilevel)
729 << Name << *NumExpansions << NewPackSize
730 << SourceRange(i->second);
731 return true;
732 }
733 }
734
735 return false;
736}
737
738Optional<unsigned> Sema::getNumArgumentsInExpansion(QualType T,
739 const MultiLevelTemplateArgumentList &TemplateArgs) {
740 QualType Pattern = cast<PackExpansionType>(T)->getPattern();
741 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
742 CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseType(Pattern);
743
744 Optional<unsigned> Result;
745 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
746 // Compute the depth and index for this parameter pack.
747 unsigned Depth;
748 unsigned Index;
749
750 if (const TemplateTypeParmType *TTP
751 = Unexpanded[I].first.dyn_cast<const TemplateTypeParmType *>()) {
752 Depth = TTP->getDepth();
753 Index = TTP->getIndex();
754 } else {
755 NamedDecl *ND = Unexpanded[I].first.get<NamedDecl *>();
756 if (isa<ParmVarDecl>(ND)) {
757 // Function parameter pack.
758 typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
759
760 llvm::PointerUnion<Decl *, DeclArgumentPack *> *Instantiation
761 = CurrentInstantiationScope->findInstantiationOf(
762 Unexpanded[I].first.get<NamedDecl *>());
763 if (Instantiation->is<Decl*>())
764 // The pattern refers to an unexpanded pack. We're not ready to expand
765 // this pack yet.
766 return None;
767
768 unsigned Size = Instantiation->get<DeclArgumentPack *>()->size();
769 assert((!Result || *Result == Size) && "inconsistent pack sizes")(static_cast <bool> ((!Result || *Result == Size) &&
"inconsistent pack sizes") ? void (0) : __assert_fail ("(!Result || *Result == Size) && \"inconsistent pack sizes\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 769, __extension__ __PRETTY_FUNCTION__))
;
770 Result = Size;
771 continue;
772 }
773
774 std::tie(Depth, Index) = getDepthAndIndex(ND);
775 }
776 if (Depth >= TemplateArgs.getNumLevels() ||
777 !TemplateArgs.hasTemplateArgument(Depth, Index))
778 // The pattern refers to an unknown template argument. We're not ready to
779 // expand this pack yet.
780 return None;
781
782 // Determine the size of the argument pack.
783 unsigned Size = TemplateArgs(Depth, Index).pack_size();
784 assert((!Result || *Result == Size) && "inconsistent pack sizes")(static_cast <bool> ((!Result || *Result == Size) &&
"inconsistent pack sizes") ? void (0) : __assert_fail ("(!Result || *Result == Size) && \"inconsistent pack sizes\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 784, __extension__ __PRETTY_FUNCTION__))
;
785 Result = Size;
786 }
787
788 return Result;
789}
790
791bool Sema::containsUnexpandedParameterPacks(Declarator &D) {
792 const DeclSpec &DS = D.getDeclSpec();
793 switch (DS.getTypeSpecType()) {
794 case TST_typename:
795 case TST_typeofType:
796 case TST_underlyingType:
797 case TST_atomic: {
798 QualType T = DS.getRepAsType().get();
799 if (!T.isNull() && T->containsUnexpandedParameterPack())
800 return true;
801 break;
802 }
803
804 case TST_typeofExpr:
805 case TST_decltype:
806 if (DS.getRepAsExpr() &&
807 DS.getRepAsExpr()->containsUnexpandedParameterPack())
808 return true;
809 break;
810
811 case TST_unspecified:
812 case TST_void:
813 case TST_char:
814 case TST_wchar:
815 case TST_char16:
816 case TST_char32:
817 case TST_int:
818 case TST_int128:
819 case TST_half:
820 case TST_float:
821 case TST_double:
822 case TST_Float16:
823 case TST_float128:
824 case TST_bool:
825 case TST_decimal32:
826 case TST_decimal64:
827 case TST_decimal128:
828 case TST_enum:
829 case TST_union:
830 case TST_struct:
831 case TST_interface:
832 case TST_class:
833 case TST_auto:
834 case TST_auto_type:
835 case TST_decltype_auto:
836#define GENERIC_IMAGE_TYPE(ImgType, Id) case TST_##ImgType##_t:
837#include "clang/Basic/OpenCLImageTypes.def"
838 case TST_unknown_anytype:
839 case TST_error:
840 break;
841 }
842
843 for (unsigned I = 0, N = D.getNumTypeObjects(); I != N; ++I) {
844 const DeclaratorChunk &Chunk = D.getTypeObject(I);
845 switch (Chunk.Kind) {
846 case DeclaratorChunk::Pointer:
847 case DeclaratorChunk::Reference:
848 case DeclaratorChunk::Paren:
849 case DeclaratorChunk::Pipe:
850 case DeclaratorChunk::BlockPointer:
851 // These declarator chunks cannot contain any parameter packs.
852 break;
853
854 case DeclaratorChunk::Array:
855 if (Chunk.Arr.NumElts &&
856 Chunk.Arr.NumElts->containsUnexpandedParameterPack())
857 return true;
858 break;
859 case DeclaratorChunk::Function:
860 for (unsigned i = 0, e = Chunk.Fun.NumParams; i != e; ++i) {
861 ParmVarDecl *Param = cast<ParmVarDecl>(Chunk.Fun.Params[i].Param);
862 QualType ParamTy = Param->getType();
863 assert(!ParamTy.isNull() && "Couldn't parse type?")(static_cast <bool> (!ParamTy.isNull() && "Couldn't parse type?"
) ? void (0) : __assert_fail ("!ParamTy.isNull() && \"Couldn't parse type?\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 863, __extension__ __PRETTY_FUNCTION__))
;
864 if (ParamTy->containsUnexpandedParameterPack()) return true;
865 }
866
867 if (Chunk.Fun.getExceptionSpecType() == EST_Dynamic) {
868 for (unsigned i = 0; i != Chunk.Fun.getNumExceptions(); ++i) {
869 if (Chunk.Fun.Exceptions[i]
870 .Ty.get()
871 ->containsUnexpandedParameterPack())
872 return true;
873 }
874 } else if (Chunk.Fun.getExceptionSpecType() == EST_ComputedNoexcept &&
875 Chunk.Fun.NoexceptExpr->containsUnexpandedParameterPack())
876 return true;
877
878 if (Chunk.Fun.hasTrailingReturnType()) {
879 QualType T = Chunk.Fun.getTrailingReturnType().get();
880 if (!T.isNull() && T->containsUnexpandedParameterPack())
881 return true;
882 }
883 break;
884
885 case DeclaratorChunk::MemberPointer:
886 if (Chunk.Mem.Scope().getScopeRep() &&
887 Chunk.Mem.Scope().getScopeRep()->containsUnexpandedParameterPack())
888 return true;
889 break;
890 }
891 }
892
893 return false;
894}
895
896namespace {
897
898// Callback to only accept typo corrections that refer to parameter packs.
899class ParameterPackValidatorCCC : public CorrectionCandidateCallback {
900 public:
901 bool ValidateCandidate(const TypoCorrection &candidate) override {
902 NamedDecl *ND = candidate.getCorrectionDecl();
903 return ND && ND->isParameterPack();
904 }
905};
906
907}
908
909/// \brief Called when an expression computing the size of a parameter pack
910/// is parsed.
911///
912/// \code
913/// template<typename ...Types> struct count {
914/// static const unsigned value = sizeof...(Types);
915/// };
916/// \endcode
917///
918//
919/// \param OpLoc The location of the "sizeof" keyword.
920/// \param Name The name of the parameter pack whose size will be determined.
921/// \param NameLoc The source location of the name of the parameter pack.
922/// \param RParenLoc The location of the closing parentheses.
923ExprResult Sema::ActOnSizeofParameterPackExpr(Scope *S,
924 SourceLocation OpLoc,
925 IdentifierInfo &Name,
926 SourceLocation NameLoc,
927 SourceLocation RParenLoc) {
928 // C++0x [expr.sizeof]p5:
929 // The identifier in a sizeof... expression shall name a parameter pack.
930 LookupResult R(*this, &Name, NameLoc, LookupOrdinaryName);
931 LookupName(R, S);
932
933 NamedDecl *ParameterPack = nullptr;
934 switch (R.getResultKind()) {
935 case LookupResult::Found:
936 ParameterPack = R.getFoundDecl();
937 break;
938
939 case LookupResult::NotFound:
940 case LookupResult::NotFoundInCurrentInstantiation:
941 if (TypoCorrection Corrected =
942 CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
943 llvm::make_unique<ParameterPackValidatorCCC>(),
944 CTK_ErrorRecovery)) {
945 diagnoseTypo(Corrected,
946 PDiag(diag::err_sizeof_pack_no_pack_name_suggest) << &Name,
947 PDiag(diag::note_parameter_pack_here));
948 ParameterPack = Corrected.getCorrectionDecl();
949 }
950
951 case LookupResult::FoundOverloaded:
952 case LookupResult::FoundUnresolvedValue:
953 break;
954
955 case LookupResult::Ambiguous:
956 DiagnoseAmbiguousLookup(R);
957 return ExprError();
958 }
959
960 if (!ParameterPack || !ParameterPack->isParameterPack()) {
961 Diag(NameLoc, diag::err_sizeof_pack_no_pack_name)
962 << &Name;
963 return ExprError();
964 }
965
966 MarkAnyDeclReferenced(OpLoc, ParameterPack, true);
967
968 return SizeOfPackExpr::Create(Context, OpLoc, ParameterPack, NameLoc,
969 RParenLoc);
970}
971
972TemplateArgumentLoc
973Sema::getTemplateArgumentPackExpansionPattern(
974 TemplateArgumentLoc OrigLoc,
975 SourceLocation &Ellipsis, Optional<unsigned> &NumExpansions) const {
976 const TemplateArgument &Argument = OrigLoc.getArgument();
977 assert(Argument.isPackExpansion())(static_cast <bool> (Argument.isPackExpansion()) ? void
(0) : __assert_fail ("Argument.isPackExpansion()", "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 977, __extension__ __PRETTY_FUNCTION__))
;
978 switch (Argument.getKind()) {
979 case TemplateArgument::Type: {
980 // FIXME: We shouldn't ever have to worry about missing
981 // type-source info!
982 TypeSourceInfo *ExpansionTSInfo = OrigLoc.getTypeSourceInfo();
983 if (!ExpansionTSInfo)
984 ExpansionTSInfo = Context.getTrivialTypeSourceInfo(Argument.getAsType(),
985 Ellipsis);
986 PackExpansionTypeLoc Expansion =
987 ExpansionTSInfo->getTypeLoc().castAs<PackExpansionTypeLoc>();
988 Ellipsis = Expansion.getEllipsisLoc();
989
990 TypeLoc Pattern = Expansion.getPatternLoc();
991 NumExpansions = Expansion.getTypePtr()->getNumExpansions();
992
993 // We need to copy the TypeLoc because TemplateArgumentLocs store a
994 // TypeSourceInfo.
995 // FIXME: Find some way to avoid the copy?
996 TypeLocBuilder TLB;
997 TLB.pushFullCopy(Pattern);
998 TypeSourceInfo *PatternTSInfo =
999 TLB.getTypeSourceInfo(Context, Pattern.getType());
1000 return TemplateArgumentLoc(TemplateArgument(Pattern.getType()),
1001 PatternTSInfo);
1002 }
1003
1004 case TemplateArgument::Expression: {
1005 PackExpansionExpr *Expansion
1006 = cast<PackExpansionExpr>(Argument.getAsExpr());
1007 Expr *Pattern = Expansion->getPattern();
1008 Ellipsis = Expansion->getEllipsisLoc();
1009 NumExpansions = Expansion->getNumExpansions();
1010 return TemplateArgumentLoc(Pattern, Pattern);
1011 }
1012
1013 case TemplateArgument::TemplateExpansion:
1014 Ellipsis = OrigLoc.getTemplateEllipsisLoc();
1015 NumExpansions = Argument.getNumTemplateExpansions();
1016 return TemplateArgumentLoc(Argument.getPackExpansionPattern(),
1017 OrigLoc.getTemplateQualifierLoc(),
1018 OrigLoc.getTemplateNameLoc());
1019
1020 case TemplateArgument::Declaration:
1021 case TemplateArgument::NullPtr:
1022 case TemplateArgument::Template:
1023 case TemplateArgument::Integral:
1024 case TemplateArgument::Pack:
1025 case TemplateArgument::Null:
1026 return TemplateArgumentLoc();
1027 }
1028
1029 llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 1029)
;
1030}
1031
1032Optional<unsigned> Sema::getFullyPackExpandedSize(TemplateArgument Arg) {
1033 assert(Arg.containsUnexpandedParameterPack())(static_cast <bool> (Arg.containsUnexpandedParameterPack
()) ? void (0) : __assert_fail ("Arg.containsUnexpandedParameterPack()"
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 1033, __extension__ __PRETTY_FUNCTION__))
;
1034
1035 // If this is a substituted pack, grab that pack. If not, we don't know
1036 // the size yet.
1037 // FIXME: We could find a size in more cases by looking for a substituted
1038 // pack anywhere within this argument, but that's not necessary in the common
1039 // case for 'sizeof...(A)' handling.
1040 TemplateArgument Pack;
1041 switch (Arg.getKind()) {
1042 case TemplateArgument::Type:
1043 if (auto *Subst = Arg.getAsType()->getAs<SubstTemplateTypeParmPackType>())
1044 Pack = Subst->getArgumentPack();
1045 else
1046 return None;
1047 break;
1048
1049 case TemplateArgument::Expression:
1050 if (auto *Subst =
1051 dyn_cast<SubstNonTypeTemplateParmPackExpr>(Arg.getAsExpr()))
1052 Pack = Subst->getArgumentPack();
1053 else if (auto *Subst = dyn_cast<FunctionParmPackExpr>(Arg.getAsExpr())) {
1054 for (ParmVarDecl *PD : *Subst)
1055 if (PD->isParameterPack())
1056 return None;
1057 return Subst->getNumExpansions();
1058 } else
1059 return None;
1060 break;
1061
1062 case TemplateArgument::Template:
1063 if (SubstTemplateTemplateParmPackStorage *Subst =
1064 Arg.getAsTemplate().getAsSubstTemplateTemplateParmPack())
1065 Pack = Subst->getArgumentPack();
1066 else
1067 return None;
1068 break;
1069
1070 case TemplateArgument::Declaration:
1071 case TemplateArgument::NullPtr:
1072 case TemplateArgument::TemplateExpansion:
1073 case TemplateArgument::Integral:
1074 case TemplateArgument::Pack:
1075 case TemplateArgument::Null:
1076 return None;
1077 }
1078
1079 // Check that no argument in the pack is itself a pack expansion.
1080 for (TemplateArgument Elem : Pack.pack_elements()) {
1081 // There's no point recursing in this case; we would have already
1082 // expanded this pack expansion into the enclosing pack if we could.
1083 if (Elem.isPackExpansion())
1084 return None;
1085 }
1086 return Pack.pack_size();
1087}
1088
1089static void CheckFoldOperand(Sema &S, Expr *E) {
1090 if (!E)
1091 return;
1092
1093 E = E->IgnoreImpCasts();
1094 auto *OCE = dyn_cast<CXXOperatorCallExpr>(E);
1095 if ((OCE && OCE->isInfixBinaryOp()) || isa<BinaryOperator>(E) ||
1096 isa<AbstractConditionalOperator>(E)) {
1097 S.Diag(E->getExprLoc(), diag::err_fold_expression_bad_operand)
1098 << E->getSourceRange()
1099 << FixItHint::CreateInsertion(E->getLocStart(), "(")
1100 << FixItHint::CreateInsertion(E->getLocEnd(), ")");
1101 }
1102}
1103
1104ExprResult Sema::ActOnCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
1105 tok::TokenKind Operator,
1106 SourceLocation EllipsisLoc, Expr *RHS,
1107 SourceLocation RParenLoc) {
1108 // LHS and RHS must be cast-expressions. We allow an arbitrary expression
1109 // in the parser and reduce down to just cast-expressions here.
1110 CheckFoldOperand(*this, LHS);
1111 CheckFoldOperand(*this, RHS);
1112
1113 auto DiscardOperands = [&] {
1114 CorrectDelayedTyposInExpr(LHS);
1115 CorrectDelayedTyposInExpr(RHS);
1116 };
1117
1118 // [expr.prim.fold]p3:
1119 // In a binary fold, op1 and op2 shall be the same fold-operator, and
1120 // either e1 shall contain an unexpanded parameter pack or e2 shall contain
1121 // an unexpanded parameter pack, but not both.
1122 if (LHS && RHS &&
1123 LHS->containsUnexpandedParameterPack() ==
1124 RHS->containsUnexpandedParameterPack()) {
1125 DiscardOperands();
1126 return Diag(EllipsisLoc,
1127 LHS->containsUnexpandedParameterPack()
1128 ? diag::err_fold_expression_packs_both_sides
1129 : diag::err_pack_expansion_without_parameter_packs)
1130 << LHS->getSourceRange() << RHS->getSourceRange();
1131 }
1132
1133 // [expr.prim.fold]p2:
1134 // In a unary fold, the cast-expression shall contain an unexpanded
1135 // parameter pack.
1136 if (!LHS || !RHS) {
1137 Expr *Pack = LHS ? LHS : RHS;
1138 assert(Pack && "fold expression with neither LHS nor RHS")(static_cast <bool> (Pack && "fold expression with neither LHS nor RHS"
) ? void (0) : __assert_fail ("Pack && \"fold expression with neither LHS nor RHS\""
, "/build/llvm-toolchain-snapshot-6.0~svn321639/tools/clang/lib/Sema/SemaTemplateVariadic.cpp"
, 1138, __extension__ __PRETTY_FUNCTION__))
;
1139 DiscardOperands();
1140 if (!Pack->containsUnexpandedParameterPack())
1141 return Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
1142 << Pack->getSourceRange();
1143 }
1144
1145 BinaryOperatorKind Opc = ConvertTokenKindToBinaryOpcode(Operator);
1146 return BuildCXXFoldExpr(LParenLoc, LHS, Opc, EllipsisLoc, RHS, RParenLoc);
1147}
1148
1149ExprResult Sema::BuildCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
1150 BinaryOperatorKind Operator,
1151 SourceLocation EllipsisLoc, Expr *RHS,
1152 SourceLocation RParenLoc) {
1153 return new (Context) CXXFoldExpr(Context.DependentTy, LParenLoc, LHS,
1154 Operator, EllipsisLoc, RHS, RParenLoc);
1155}
1156
1157ExprResult Sema::BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc,
1158 BinaryOperatorKind Operator) {
1159 // [temp.variadic]p9:
1160 // If N is zero for a unary fold-expression, the value of the expression is
1161 // && -> true
1162 // || -> false
1163 // , -> void()
1164 // if the operator is not listed [above], the instantiation is ill-formed.
1165 //
1166 // Note that we need to use something like int() here, not merely 0, to
1167 // prevent the result from being a null pointer constant.
1168 QualType ScalarType;
1169 switch (Operator) {
1170 case BO_LOr:
1171 return ActOnCXXBoolLiteral(EllipsisLoc, tok::kw_false);
1172 case BO_LAnd:
1173 return ActOnCXXBoolLiteral(EllipsisLoc, tok::kw_true);
1174 case BO_Comma:
1175 ScalarType = Context.VoidTy;
1176 break;
1177
1178 default:
1179 return Diag(EllipsisLoc, diag::err_fold_expression_empty)
1180 << BinaryOperator::getOpcodeStr(Operator);
1181 }
1182
1183 return new (Context) CXXScalarValueInitExpr(
1184 ScalarType, Context.getTrivialTypeSourceInfo(ScalarType, EllipsisLoc),
1185 EllipsisLoc);
1186}