1 //===- TemplateBase.cpp - Common template AST class implementation --------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements common classes used throughout C++ template
10 // representations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/AST/TemplateBase.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/Decl.h"
17 #include "clang/AST/DeclBase.h"
18 #include "clang/AST/DeclTemplate.h"
19 #include "clang/AST/DependenceFlags.h"
20 #include "clang/AST/Expr.h"
21 #include "clang/AST/ExprCXX.h"
22 #include "clang/AST/PrettyPrinter.h"
23 #include "clang/AST/TemplateName.h"
24 #include "clang/AST/Type.h"
25 #include "clang/AST/TypeLoc.h"
26 #include "clang/Basic/Diagnostic.h"
27 #include "clang/Basic/LLVM.h"
28 #include "clang/Basic/LangOptions.h"
29 #include "clang/Basic/SourceLocation.h"
30 #include "llvm/ADT/APSInt.h"
31 #include "llvm/ADT/FoldingSet.h"
32 #include "llvm/ADT/None.h"
33 #include "llvm/ADT/SmallString.h"
34 #include "llvm/ADT/StringRef.h"
35 #include "llvm/Support/Casting.h"
36 #include "llvm/Support/Compiler.h"
37 #include "llvm/Support/ErrorHandling.h"
38 #include "llvm/Support/raw_ostream.h"
39 #include <cassert>
40 #include <cstddef>
41 #include <cstdint>
42 #include <cstring>
43 
44 using namespace clang;
45 
46 /// Print a template integral argument value.
47 ///
48 /// \param TemplArg the TemplateArgument instance to print.
49 ///
50 /// \param Out the raw_ostream instance to use for printing.
51 ///
52 /// \param Policy the printing policy for EnumConstantDecl printing.
53 static void printIntegral(const TemplateArgument &TemplArg,
54                           raw_ostream &Out, const PrintingPolicy& Policy) {
55   const Type *T = TemplArg.getIntegralType().getTypePtr();
56   const llvm::APSInt &Val = TemplArg.getAsIntegral();
57 
58   if (const EnumType *ET = T->getAs<EnumType>()) {
59     for (const EnumConstantDecl* ECD : ET->getDecl()->enumerators()) {
60       // In Sema::CheckTemplateArugment, enum template arguments value are
61       // extended to the size of the integer underlying the enum type.  This
62       // may create a size difference between the enum value and template
63       // argument value, requiring isSameValue here instead of operator==.
64       if (llvm::APSInt::isSameValue(ECD->getInitVal(), Val)) {
65         ECD->printQualifiedName(Out, Policy);
66         return;
67       }
68     }
69   }
70 
71   if (T->isBooleanType() && !Policy.MSVCFormatting) {
72     Out << (Val.getBoolValue() ? "true" : "false");
73   } else if (T->isCharType()) {
74     const char Ch = Val.getZExtValue();
75     Out << ((Ch == '\'') ? "'\\" : "'");
76     Out.write_escaped(StringRef(&Ch, 1), /*UseHexEscapes=*/ true);
77     Out << "'";
78   } else {
79     Out << Val;
80   }
81 }
82 
83 //===----------------------------------------------------------------------===//
84 // TemplateArgument Implementation
85 //===----------------------------------------------------------------------===//
86 
87 TemplateArgument::TemplateArgument(const ASTContext &Ctx,
88                                    const llvm::APSInt &Value, QualType Type) {
89   Integer.Kind = Integral;
90   // Copy the APSInt value into our decomposed form.
91   Integer.BitWidth = Value.getBitWidth();
92   Integer.IsUnsigned = Value.isUnsigned();
93   // If the value is large, we have to get additional memory from the ASTContext
94   unsigned NumWords = Value.getNumWords();
95   if (NumWords > 1) {
96     void *Mem = Ctx.Allocate(NumWords * sizeof(uint64_t));
97     std::memcpy(Mem, Value.getRawData(), NumWords * sizeof(uint64_t));
98     Integer.pVal = static_cast<uint64_t *>(Mem);
99   } else {
100     Integer.VAL = Value.getZExtValue();
101   }
102 
103   Integer.Type = Type.getAsOpaquePtr();
104 }
105 
106 static const ValueDecl *getAsSimpleValueDeclRef(const ASTContext &Ctx,
107                                                 QualType T, const APValue &V) {
108   // Pointers to members are relatively easy.
109   if (V.isMemberPointer() && V.getMemberPointerPath().empty())
110     return V.getMemberPointerDecl();
111 
112   // We model class non-type template parameters as their template parameter
113   // object declaration.
114   if (V.isStruct() || V.isUnion())
115     return Ctx.getTemplateParamObjectDecl(T, V);
116 
117   // Pointers and references with an empty path use the special 'Declaration'
118   // representation.
119   if (V.isLValue() && V.hasLValuePath() &&
120       V.getLValuePath().empty() && !V.isLValueOnePastTheEnd())
121     return V.getLValueBase().dyn_cast<const ValueDecl *>();
122 
123   // Everything else uses the 'uncommon' representation.
124   return nullptr;
125 }
126 
127 TemplateArgument::TemplateArgument(const ASTContext &Ctx, QualType Type,
128                                    const APValue &V) {
129   if (Type->isIntegralOrEnumerationType() && V.isInt())
130     *this = TemplateArgument(Ctx, V.getInt(), Type);
131   else if ((V.isLValue() && V.isNullPointer()) ||
132            (V.isMemberPointer() && !V.getMemberPointerDecl()))
133     *this = TemplateArgument(Type, /*isNullPtr=*/true);
134   else if (const ValueDecl *VD = getAsSimpleValueDeclRef(Ctx, Type, V))
135     // FIXME: The Declaration form should expose a const ValueDecl*.
136     *this = TemplateArgument(const_cast<ValueDecl*>(VD), Type);
137   else {
138     Value.Kind = UncommonValue;
139     Value.Value = new (Ctx) APValue(V);
140     Ctx.addDestruction(Value.Value);
141     Value.Type = Type.getAsOpaquePtr();
142   }
143 }
144 
145 TemplateArgument
146 TemplateArgument::CreatePackCopy(ASTContext &Context,
147                                  ArrayRef<TemplateArgument> Args) {
148   if (Args.empty())
149     return getEmptyPack();
150 
151   return TemplateArgument(Args.copy(Context));
152 }
153 
154 TemplateArgumentDependence TemplateArgument::getDependence() const {
155   auto Deps = TemplateArgumentDependence::None;
156   switch (getKind()) {
157   case Null:
158     llvm_unreachable("Should not have a NULL template argument");
159 
160   case Type:
161     Deps = toTemplateArgumentDependence(getAsType()->getDependence());
162     if (isa<PackExpansionType>(getAsType()))
163       Deps |= TemplateArgumentDependence::Dependent;
164     return Deps;
165 
166   case Template:
167     return toTemplateArgumentDependence(getAsTemplate().getDependence());
168 
169   case TemplateExpansion:
170     return TemplateArgumentDependence::Dependent |
171            TemplateArgumentDependence::Instantiation;
172 
173   case NullPtr:
174   case Integral:
175   case Declaration:
176   case UncommonValue:
177     return TemplateArgumentDependence::None;
178 
179   case Expression:
180     Deps = toTemplateArgumentDependence(getAsExpr()->getDependence());
181     // Instantiation-dependent expression arguments are considered dependent
182     // until they're resolved to another form.
183     if (Deps & TemplateArgumentDependence::Instantiation)
184       Deps |= TemplateArgumentDependence::Dependent;
185     return Deps;
186 
187   case Pack:
188     for (const auto &P : pack_elements())
189       Deps |= P.getDependence();
190     return Deps;
191   }
192   llvm_unreachable("unhandled ArgKind");
193 }
194 
195 bool TemplateArgument::isDependent() const {
196   return getDependence() & TemplateArgumentDependence::Dependent;
197 }
198 
199 bool TemplateArgument::isInstantiationDependent() const {
200   return getDependence() & TemplateArgumentDependence::Instantiation;
201 }
202 
203 bool TemplateArgument::isPackExpansion() const {
204   switch (getKind()) {
205   case Null:
206   case Declaration:
207   case Integral:
208   case UncommonValue:
209   case Pack:
210   case Template:
211   case NullPtr:
212     return false;
213 
214   case TemplateExpansion:
215     return true;
216 
217   case Type:
218     return isa<PackExpansionType>(getAsType());
219 
220   case Expression:
221     return isa<PackExpansionExpr>(getAsExpr());
222   }
223 
224   llvm_unreachable("Invalid TemplateArgument Kind!");
225 }
226 
227 bool TemplateArgument::containsUnexpandedParameterPack() const {
228   return getDependence() & TemplateArgumentDependence::UnexpandedPack;
229 }
230 
231 Optional<unsigned> TemplateArgument::getNumTemplateExpansions() const {
232   assert(getKind() == TemplateExpansion);
233   if (TemplateArg.NumExpansions)
234     return TemplateArg.NumExpansions - 1;
235 
236   return None;
237 }
238 
239 QualType TemplateArgument::getNonTypeTemplateArgumentType() const {
240   switch (getKind()) {
241   case TemplateArgument::Null:
242   case TemplateArgument::Type:
243   case TemplateArgument::Template:
244   case TemplateArgument::TemplateExpansion:
245   case TemplateArgument::Pack:
246     return QualType();
247 
248   case TemplateArgument::Integral:
249     return getIntegralType();
250 
251   case TemplateArgument::Expression:
252     return getAsExpr()->getType();
253 
254   case TemplateArgument::Declaration:
255     return getParamTypeForDecl();
256 
257   case TemplateArgument::NullPtr:
258     return getNullPtrType();
259 
260   case TemplateArgument::UncommonValue:
261     return getUncommonValueType();
262   }
263 
264   llvm_unreachable("Invalid TemplateArgument Kind!");
265 }
266 
267 void TemplateArgument::Profile(llvm::FoldingSetNodeID &ID,
268                                const ASTContext &Context) const {
269   ID.AddInteger(getKind());
270   switch (getKind()) {
271   case Null:
272     break;
273 
274   case Type:
275     getAsType().Profile(ID);
276     break;
277 
278   case NullPtr:
279     getNullPtrType().Profile(ID);
280     break;
281 
282   case Declaration:
283     getParamTypeForDecl().Profile(ID);
284     ID.AddPointer(getAsDecl()? getAsDecl()->getCanonicalDecl() : nullptr);
285     break;
286 
287   case Template:
288   case TemplateExpansion: {
289     TemplateName Template = getAsTemplateOrTemplatePattern();
290     if (TemplateTemplateParmDecl *TTP
291           = dyn_cast_or_null<TemplateTemplateParmDecl>(
292                                                 Template.getAsTemplateDecl())) {
293       ID.AddBoolean(true);
294       ID.AddInteger(TTP->getDepth());
295       ID.AddInteger(TTP->getPosition());
296       ID.AddBoolean(TTP->isParameterPack());
297     } else {
298       ID.AddBoolean(false);
299       ID.AddPointer(Context.getCanonicalTemplateName(Template)
300                                                           .getAsVoidPointer());
301     }
302     break;
303   }
304 
305   case Integral:
306     getIntegralType().Profile(ID);
307     getAsIntegral().Profile(ID);
308     break;
309 
310   case UncommonValue:
311     getUncommonValueType().Profile(ID);
312     getAsUncommonValue().Profile(ID);
313     break;
314 
315   case Expression:
316     getAsExpr()->Profile(ID, Context, true);
317     break;
318 
319   case Pack:
320     ID.AddInteger(Args.NumArgs);
321     for (unsigned I = 0; I != Args.NumArgs; ++I)
322       Args.Args[I].Profile(ID, Context);
323   }
324 }
325 
326 bool TemplateArgument::structurallyEquals(const TemplateArgument &Other) const {
327   if (getKind() != Other.getKind()) return false;
328 
329   switch (getKind()) {
330   case Null:
331   case Type:
332   case Expression:
333   case NullPtr:
334     return TypeOrValue.V == Other.TypeOrValue.V;
335 
336   case Template:
337   case TemplateExpansion:
338     return TemplateArg.Name == Other.TemplateArg.Name &&
339            TemplateArg.NumExpansions == Other.TemplateArg.NumExpansions;
340 
341   case Declaration:
342     return getAsDecl() == Other.getAsDecl();
343 
344   case Integral:
345     return getIntegralType() == Other.getIntegralType() &&
346            getAsIntegral() == Other.getAsIntegral();
347 
348   case UncommonValue: {
349     if (getUncommonValueType() != Other.getUncommonValueType())
350       return false;
351 
352     llvm::FoldingSetNodeID A, B;
353     getAsUncommonValue().Profile(A);
354     Other.getAsUncommonValue().Profile(B);
355     return A == B;
356   }
357 
358   case Pack:
359     if (Args.NumArgs != Other.Args.NumArgs) return false;
360     for (unsigned I = 0, E = Args.NumArgs; I != E; ++I)
361       if (!Args.Args[I].structurallyEquals(Other.Args.Args[I]))
362         return false;
363     return true;
364   }
365 
366   llvm_unreachable("Invalid TemplateArgument Kind!");
367 }
368 
369 TemplateArgument TemplateArgument::getPackExpansionPattern() const {
370   assert(isPackExpansion());
371 
372   switch (getKind()) {
373   case Type:
374     return getAsType()->castAs<PackExpansionType>()->getPattern();
375 
376   case Expression:
377     return cast<PackExpansionExpr>(getAsExpr())->getPattern();
378 
379   case TemplateExpansion:
380     return TemplateArgument(getAsTemplateOrTemplatePattern());
381 
382   case Declaration:
383   case Integral:
384   case UncommonValue:
385   case Pack:
386   case Null:
387   case Template:
388   case NullPtr:
389     return TemplateArgument();
390   }
391 
392   llvm_unreachable("Invalid TemplateArgument Kind!");
393 }
394 
395 void TemplateArgument::print(const PrintingPolicy &Policy,
396                              raw_ostream &Out) const {
397   switch (getKind()) {
398   case Null:
399     Out << "(no value)";
400     break;
401 
402   case Type: {
403     PrintingPolicy SubPolicy(Policy);
404     SubPolicy.SuppressStrongLifetime = true;
405     getAsType().print(Out, SubPolicy);
406     break;
407   }
408 
409   case Declaration: {
410     NamedDecl *ND = getAsDecl();
411     if (getParamTypeForDecl()->isRecordType()) {
412       if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(ND)) {
413         // FIXME: Include the type if it's not obvious from the context.
414         TPO->printAsInit(Out);
415         break;
416       }
417     }
418     if (!getParamTypeForDecl()->isReferenceType())
419       Out << '&';
420     ND->printQualifiedName(Out);
421     break;
422   }
423 
424   case UncommonValue:
425     getAsUncommonValue().printPretty(Out, Policy, getUncommonValueType());
426     break;
427 
428   case NullPtr:
429     Out << "nullptr";
430     break;
431 
432   case Template:
433     getAsTemplate().print(Out, Policy);
434     break;
435 
436   case TemplateExpansion:
437     getAsTemplateOrTemplatePattern().print(Out, Policy);
438     Out << "...";
439     break;
440 
441   case Integral:
442     printIntegral(*this, Out, Policy);
443     break;
444 
445   case Expression:
446     getAsExpr()->printPretty(Out, nullptr, Policy);
447     break;
448 
449   case Pack:
450     Out << "<";
451     bool First = true;
452     for (const auto &P : pack_elements()) {
453       if (First)
454         First = false;
455       else
456         Out << ", ";
457 
458       P.print(Policy, Out);
459     }
460     Out << ">";
461     break;
462   }
463 }
464 
465 void TemplateArgument::dump(raw_ostream &Out) const {
466   LangOptions LO; // FIXME! see also TemplateName::dump().
467   LO.CPlusPlus = true;
468   LO.Bool = true;
469   print(PrintingPolicy(LO), Out);
470 }
471 
472 LLVM_DUMP_METHOD void TemplateArgument::dump() const { dump(llvm::errs()); }
473 
474 //===----------------------------------------------------------------------===//
475 // TemplateArgumentLoc Implementation
476 //===----------------------------------------------------------------------===//
477 
478 SourceRange TemplateArgumentLoc::getSourceRange() const {
479   switch (Argument.getKind()) {
480   case TemplateArgument::Expression:
481     return getSourceExpression()->getSourceRange();
482 
483   case TemplateArgument::Declaration:
484     return getSourceDeclExpression()->getSourceRange();
485 
486   case TemplateArgument::NullPtr:
487     return getSourceNullPtrExpression()->getSourceRange();
488 
489   case TemplateArgument::Type:
490     if (TypeSourceInfo *TSI = getTypeSourceInfo())
491       return TSI->getTypeLoc().getSourceRange();
492     else
493       return SourceRange();
494 
495   case TemplateArgument::Template:
496     if (getTemplateQualifierLoc())
497       return SourceRange(getTemplateQualifierLoc().getBeginLoc(),
498                          getTemplateNameLoc());
499     return SourceRange(getTemplateNameLoc());
500 
501   case TemplateArgument::TemplateExpansion:
502     if (getTemplateQualifierLoc())
503       return SourceRange(getTemplateQualifierLoc().getBeginLoc(),
504                          getTemplateEllipsisLoc());
505     return SourceRange(getTemplateNameLoc(), getTemplateEllipsisLoc());
506 
507   case TemplateArgument::Integral:
508     return getSourceIntegralExpression()->getSourceRange();
509 
510   case TemplateArgument::UncommonValue:
511     return getSourceUncommonValueExpression()->getSourceRange();
512 
513   case TemplateArgument::Pack:
514   case TemplateArgument::Null:
515     return SourceRange();
516   }
517 
518   llvm_unreachable("Invalid TemplateArgument Kind!");
519 }
520 
521 template <typename T>
522 static const T &DiagTemplateArg(const T &DB, const TemplateArgument &Arg) {
523   switch (Arg.getKind()) {
524   case TemplateArgument::Null:
525     // This is bad, but not as bad as crashing because of argument
526     // count mismatches.
527     return DB << "(null template argument)";
528 
529   case TemplateArgument::Type:
530     return DB << Arg.getAsType();
531 
532   case TemplateArgument::Declaration:
533     return DB << Arg.getAsDecl();
534 
535   case TemplateArgument::NullPtr:
536     return DB << "nullptr";
537 
538   case TemplateArgument::Integral:
539     return DB << Arg.getAsIntegral().toString(10);
540 
541   case TemplateArgument::UncommonValue: {
542     // FIXME: We're guessing at LangOptions!
543     SmallString<32> Str;
544     llvm::raw_svector_ostream OS(Str);
545     LangOptions LangOpts;
546     LangOpts.CPlusPlus = true;
547     PrintingPolicy Policy(LangOpts);
548     Arg.getAsUncommonValue().printPretty(OS, Policy,
549                                          Arg.getUncommonValueType());
550     return DB << OS.str();
551   }
552 
553   case TemplateArgument::Template:
554     return DB << Arg.getAsTemplate();
555 
556   case TemplateArgument::TemplateExpansion:
557     return DB << Arg.getAsTemplateOrTemplatePattern() << "...";
558 
559   case TemplateArgument::Expression: {
560     // This shouldn't actually ever happen, so it's okay that we're
561     // regurgitating an expression here.
562     // FIXME: We're guessing at LangOptions!
563     SmallString<32> Str;
564     llvm::raw_svector_ostream OS(Str);
565     LangOptions LangOpts;
566     LangOpts.CPlusPlus = true;
567     PrintingPolicy Policy(LangOpts);
568     Arg.getAsExpr()->printPretty(OS, nullptr, Policy);
569     return DB << OS.str();
570   }
571 
572   case TemplateArgument::Pack: {
573     // FIXME: We're guessing at LangOptions!
574     SmallString<32> Str;
575     llvm::raw_svector_ostream OS(Str);
576     LangOptions LangOpts;
577     LangOpts.CPlusPlus = true;
578     PrintingPolicy Policy(LangOpts);
579     Arg.print(Policy, OS);
580     return DB << OS.str();
581   }
582   }
583 
584   llvm_unreachable("Invalid TemplateArgument Kind!");
585 }
586 
587 const StreamingDiagnostic &clang::operator<<(const StreamingDiagnostic &DB,
588                                              const TemplateArgument &Arg) {
589   return DiagTemplateArg(DB, Arg);
590 }
591 
592 clang::TemplateArgumentLocInfo::TemplateArgumentLocInfo(
593     ASTContext &Ctx, NestedNameSpecifierLoc QualifierLoc,
594     SourceLocation TemplateNameLoc, SourceLocation EllipsisLoc) {
595   TemplateTemplateArgLocInfo *Template = new (Ctx) TemplateTemplateArgLocInfo;
596   Template->Qualifier = QualifierLoc.getNestedNameSpecifier();
597   Template->QualifierLocData = QualifierLoc.getOpaqueData();
598   Template->TemplateNameLoc = TemplateNameLoc;
599   Template->EllipsisLoc = EllipsisLoc;
600   Pointer = Template;
601 }
602 
603 const ASTTemplateArgumentListInfo *
604 ASTTemplateArgumentListInfo::Create(const ASTContext &C,
605                                     const TemplateArgumentListInfo &List) {
606   std::size_t size = totalSizeToAlloc<TemplateArgumentLoc>(List.size());
607   void *Mem = C.Allocate(size, alignof(ASTTemplateArgumentListInfo));
608   return new (Mem) ASTTemplateArgumentListInfo(List);
609 }
610 
611 ASTTemplateArgumentListInfo::ASTTemplateArgumentListInfo(
612     const TemplateArgumentListInfo &Info) {
613   LAngleLoc = Info.getLAngleLoc();
614   RAngleLoc = Info.getRAngleLoc();
615   NumTemplateArgs = Info.size();
616 
617   TemplateArgumentLoc *ArgBuffer = getTrailingObjects<TemplateArgumentLoc>();
618   std::uninitialized_copy(Info.arguments().begin(), Info.arguments().end(),
619                           ArgBuffer);
620 }
621 
622 void ASTTemplateKWAndArgsInfo::initializeFrom(
623     SourceLocation TemplateKWLoc, const TemplateArgumentListInfo &Info,
624     TemplateArgumentLoc *OutArgArray) {
625   this->TemplateKWLoc = TemplateKWLoc;
626   LAngleLoc = Info.getLAngleLoc();
627   RAngleLoc = Info.getRAngleLoc();
628   NumTemplateArgs = Info.size();
629   std::uninitialized_copy(Info.arguments().begin(), Info.arguments().end(),
630                           OutArgArray);
631 }
632 
633 void ASTTemplateKWAndArgsInfo::initializeFrom(SourceLocation TemplateKWLoc) {
634   assert(TemplateKWLoc.isValid());
635   LAngleLoc = SourceLocation();
636   RAngleLoc = SourceLocation();
637   this->TemplateKWLoc = TemplateKWLoc;
638   NumTemplateArgs = 0;
639 }
640 
641 void ASTTemplateKWAndArgsInfo::copyInto(const TemplateArgumentLoc *ArgArray,
642                                         TemplateArgumentListInfo &Info) const {
643   Info.setLAngleLoc(LAngleLoc);
644   Info.setRAngleLoc(RAngleLoc);
645   for (unsigned I = 0; I != NumTemplateArgs; ++I)
646     Info.addArgument(ArgArray[I]);
647 }
648