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(ASTContext &Ctx, const llvm::APSInt &Value,
88                                    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 TemplateArgument
107 TemplateArgument::CreatePackCopy(ASTContext &Context,
108                                  ArrayRef<TemplateArgument> Args) {
109   if (Args.empty())
110     return getEmptyPack();
111 
112   return TemplateArgument(Args.copy(Context));
113 }
114 
115 TemplateArgumentDependence TemplateArgument::getDependence() const {
116   auto Deps = TemplateArgumentDependence::None;
117   switch (getKind()) {
118   case Null:
119     llvm_unreachable("Should not have a NULL template argument");
120 
121   case Type:
122     Deps = toTemplateArgumentDependence(getAsType()->getDependence());
123     if (isa<PackExpansionType>(getAsType()))
124       Deps |= TemplateArgumentDependence::Dependent;
125     return Deps;
126 
127   case Template:
128     return toTemplateArgumentDependence(getAsTemplate().getDependence());
129 
130   case TemplateExpansion:
131     return TemplateArgumentDependence::Dependent |
132            TemplateArgumentDependence::Instantiation;
133 
134   case Declaration: {
135     auto *DC = dyn_cast<DeclContext>(getAsDecl());
136     if (!DC)
137       DC = getAsDecl()->getDeclContext();
138     if (DC->isDependentContext())
139       Deps = TemplateArgumentDependence::Dependent |
140              TemplateArgumentDependence::Instantiation;
141     return Deps;
142   }
143 
144   case NullPtr:
145   case Integral:
146     return TemplateArgumentDependence::None;
147 
148   case Expression:
149     Deps = toTemplateArgumentDependence(getAsExpr()->getDependence());
150     if (isa<PackExpansionExpr>(getAsExpr()))
151       Deps |= TemplateArgumentDependence::Dependent |
152               TemplateArgumentDependence::Instantiation;
153     return Deps;
154 
155   case Pack:
156     for (const auto &P : pack_elements())
157       Deps |= P.getDependence();
158     return Deps;
159   }
160   llvm_unreachable("unhandled ArgKind");
161 }
162 
163 bool TemplateArgument::isDependent() const {
164   return getDependence() & TemplateArgumentDependence::Dependent;
165 }
166 
167 bool TemplateArgument::isInstantiationDependent() const {
168   return getDependence() & TemplateArgumentDependence::Instantiation;
169 }
170 
171 bool TemplateArgument::isPackExpansion() const {
172   switch (getKind()) {
173   case Null:
174   case Declaration:
175   case Integral:
176   case Pack:
177   case Template:
178   case NullPtr:
179     return false;
180 
181   case TemplateExpansion:
182     return true;
183 
184   case Type:
185     return isa<PackExpansionType>(getAsType());
186 
187   case Expression:
188     return isa<PackExpansionExpr>(getAsExpr());
189   }
190 
191   llvm_unreachable("Invalid TemplateArgument Kind!");
192 }
193 
194 bool TemplateArgument::containsUnexpandedParameterPack() const {
195   return getDependence() & TemplateArgumentDependence::UnexpandedPack;
196 }
197 
198 Optional<unsigned> TemplateArgument::getNumTemplateExpansions() const {
199   assert(getKind() == TemplateExpansion);
200   if (TemplateArg.NumExpansions)
201     return TemplateArg.NumExpansions - 1;
202 
203   return None;
204 }
205 
206 QualType TemplateArgument::getNonTypeTemplateArgumentType() const {
207   switch (getKind()) {
208   case TemplateArgument::Null:
209   case TemplateArgument::Type:
210   case TemplateArgument::Template:
211   case TemplateArgument::TemplateExpansion:
212   case TemplateArgument::Pack:
213     return QualType();
214 
215   case TemplateArgument::Integral:
216     return getIntegralType();
217 
218   case TemplateArgument::Expression:
219     return getAsExpr()->getType();
220 
221   case TemplateArgument::Declaration:
222     return getParamTypeForDecl();
223 
224   case TemplateArgument::NullPtr:
225     return getNullPtrType();
226   }
227 
228   llvm_unreachable("Invalid TemplateArgument Kind!");
229 }
230 
231 void TemplateArgument::Profile(llvm::FoldingSetNodeID &ID,
232                                const ASTContext &Context) const {
233   ID.AddInteger(getKind());
234   switch (getKind()) {
235   case Null:
236     break;
237 
238   case Type:
239     getAsType().Profile(ID);
240     break;
241 
242   case NullPtr:
243     getNullPtrType().Profile(ID);
244     break;
245 
246   case Declaration:
247     ID.AddPointer(getAsDecl()? getAsDecl()->getCanonicalDecl() : nullptr);
248     break;
249 
250   case Template:
251   case TemplateExpansion: {
252     TemplateName Template = getAsTemplateOrTemplatePattern();
253     if (TemplateTemplateParmDecl *TTP
254           = dyn_cast_or_null<TemplateTemplateParmDecl>(
255                                                 Template.getAsTemplateDecl())) {
256       ID.AddBoolean(true);
257       ID.AddInteger(TTP->getDepth());
258       ID.AddInteger(TTP->getPosition());
259       ID.AddBoolean(TTP->isParameterPack());
260     } else {
261       ID.AddBoolean(false);
262       ID.AddPointer(Context.getCanonicalTemplateName(Template)
263                                                           .getAsVoidPointer());
264     }
265     break;
266   }
267 
268   case Integral:
269     getAsIntegral().Profile(ID);
270     getIntegralType().Profile(ID);
271     break;
272 
273   case Expression:
274     getAsExpr()->Profile(ID, Context, true);
275     break;
276 
277   case Pack:
278     ID.AddInteger(Args.NumArgs);
279     for (unsigned I = 0; I != Args.NumArgs; ++I)
280       Args.Args[I].Profile(ID, Context);
281   }
282 }
283 
284 bool TemplateArgument::structurallyEquals(const TemplateArgument &Other) const {
285   if (getKind() != Other.getKind()) return false;
286 
287   switch (getKind()) {
288   case Null:
289   case Type:
290   case Expression:
291   case Template:
292   case TemplateExpansion:
293   case NullPtr:
294     return TypeOrValue.V == Other.TypeOrValue.V;
295 
296   case Declaration:
297     return getAsDecl() == Other.getAsDecl();
298 
299   case Integral:
300     return getIntegralType() == Other.getIntegralType() &&
301            getAsIntegral() == Other.getAsIntegral();
302 
303   case Pack:
304     if (Args.NumArgs != Other.Args.NumArgs) return false;
305     for (unsigned I = 0, E = Args.NumArgs; I != E; ++I)
306       if (!Args.Args[I].structurallyEquals(Other.Args.Args[I]))
307         return false;
308     return true;
309   }
310 
311   llvm_unreachable("Invalid TemplateArgument Kind!");
312 }
313 
314 TemplateArgument TemplateArgument::getPackExpansionPattern() const {
315   assert(isPackExpansion());
316 
317   switch (getKind()) {
318   case Type:
319     return getAsType()->castAs<PackExpansionType>()->getPattern();
320 
321   case Expression:
322     return cast<PackExpansionExpr>(getAsExpr())->getPattern();
323 
324   case TemplateExpansion:
325     return TemplateArgument(getAsTemplateOrTemplatePattern());
326 
327   case Declaration:
328   case Integral:
329   case Pack:
330   case Null:
331   case Template:
332   case NullPtr:
333     return TemplateArgument();
334   }
335 
336   llvm_unreachable("Invalid TemplateArgument Kind!");
337 }
338 
339 void TemplateArgument::print(const PrintingPolicy &Policy,
340                              raw_ostream &Out) const {
341   switch (getKind()) {
342   case Null:
343     Out << "(no value)";
344     break;
345 
346   case Type: {
347     PrintingPolicy SubPolicy(Policy);
348     SubPolicy.SuppressStrongLifetime = true;
349     getAsType().print(Out, SubPolicy);
350     break;
351   }
352 
353   case Declaration: {
354     NamedDecl *ND = getAsDecl();
355     if (getParamTypeForDecl()->isRecordType()) {
356       if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(ND)) {
357         // FIXME: Include the type if it's not obvious from the context.
358         TPO->printAsInit(Out);
359         break;
360       }
361     }
362     if (!getParamTypeForDecl()->isReferenceType())
363       Out << '&';
364     ND->printQualifiedName(Out);
365     break;
366   }
367 
368   case NullPtr:
369     Out << "nullptr";
370     break;
371 
372   case Template:
373     getAsTemplate().print(Out, Policy);
374     break;
375 
376   case TemplateExpansion:
377     getAsTemplateOrTemplatePattern().print(Out, Policy);
378     Out << "...";
379     break;
380 
381   case Integral:
382     printIntegral(*this, Out, Policy);
383     break;
384 
385   case Expression:
386     getAsExpr()->printPretty(Out, nullptr, Policy);
387     break;
388 
389   case Pack:
390     Out << "<";
391     bool First = true;
392     for (const auto &P : pack_elements()) {
393       if (First)
394         First = false;
395       else
396         Out << ", ";
397 
398       P.print(Policy, Out);
399     }
400     Out << ">";
401     break;
402   }
403 }
404 
405 void TemplateArgument::dump(raw_ostream &Out) const {
406   LangOptions LO; // FIXME! see also TemplateName::dump().
407   LO.CPlusPlus = true;
408   LO.Bool = true;
409   print(PrintingPolicy(LO), Out);
410 }
411 
412 LLVM_DUMP_METHOD void TemplateArgument::dump() const { dump(llvm::errs()); }
413 
414 //===----------------------------------------------------------------------===//
415 // TemplateArgumentLoc Implementation
416 //===----------------------------------------------------------------------===//
417 
418 SourceRange TemplateArgumentLoc::getSourceRange() const {
419   switch (Argument.getKind()) {
420   case TemplateArgument::Expression:
421     return getSourceExpression()->getSourceRange();
422 
423   case TemplateArgument::Declaration:
424     return getSourceDeclExpression()->getSourceRange();
425 
426   case TemplateArgument::NullPtr:
427     return getSourceNullPtrExpression()->getSourceRange();
428 
429   case TemplateArgument::Type:
430     if (TypeSourceInfo *TSI = getTypeSourceInfo())
431       return TSI->getTypeLoc().getSourceRange();
432     else
433       return SourceRange();
434 
435   case TemplateArgument::Template:
436     if (getTemplateQualifierLoc())
437       return SourceRange(getTemplateQualifierLoc().getBeginLoc(),
438                          getTemplateNameLoc());
439     return SourceRange(getTemplateNameLoc());
440 
441   case TemplateArgument::TemplateExpansion:
442     if (getTemplateQualifierLoc())
443       return SourceRange(getTemplateQualifierLoc().getBeginLoc(),
444                          getTemplateEllipsisLoc());
445     return SourceRange(getTemplateNameLoc(), getTemplateEllipsisLoc());
446 
447   case TemplateArgument::Integral:
448     return getSourceIntegralExpression()->getSourceRange();
449 
450   case TemplateArgument::Pack:
451   case TemplateArgument::Null:
452     return SourceRange();
453   }
454 
455   llvm_unreachable("Invalid TemplateArgument Kind!");
456 }
457 
458 template <typename T>
459 static const T &DiagTemplateArg(const T &DB, const TemplateArgument &Arg) {
460   switch (Arg.getKind()) {
461   case TemplateArgument::Null:
462     // This is bad, but not as bad as crashing because of argument
463     // count mismatches.
464     return DB << "(null template argument)";
465 
466   case TemplateArgument::Type:
467     return DB << Arg.getAsType();
468 
469   case TemplateArgument::Declaration:
470     return DB << Arg.getAsDecl();
471 
472   case TemplateArgument::NullPtr:
473     return DB << "nullptr";
474 
475   case TemplateArgument::Integral:
476     return DB << Arg.getAsIntegral().toString(10);
477 
478   case TemplateArgument::Template:
479     return DB << Arg.getAsTemplate();
480 
481   case TemplateArgument::TemplateExpansion:
482     return DB << Arg.getAsTemplateOrTemplatePattern() << "...";
483 
484   case TemplateArgument::Expression: {
485     // This shouldn't actually ever happen, so it's okay that we're
486     // regurgitating an expression here.
487     // FIXME: We're guessing at LangOptions!
488     SmallString<32> Str;
489     llvm::raw_svector_ostream OS(Str);
490     LangOptions LangOpts;
491     LangOpts.CPlusPlus = true;
492     PrintingPolicy Policy(LangOpts);
493     Arg.getAsExpr()->printPretty(OS, nullptr, Policy);
494     return DB << OS.str();
495   }
496 
497   case TemplateArgument::Pack: {
498     // FIXME: We're guessing at LangOptions!
499     SmallString<32> Str;
500     llvm::raw_svector_ostream OS(Str);
501     LangOptions LangOpts;
502     LangOpts.CPlusPlus = true;
503     PrintingPolicy Policy(LangOpts);
504     Arg.print(Policy, OS);
505     return DB << OS.str();
506   }
507   }
508 
509   llvm_unreachable("Invalid TemplateArgument Kind!");
510 }
511 
512 const StreamingDiagnostic &clang::operator<<(const StreamingDiagnostic &DB,
513                                              const TemplateArgument &Arg) {
514   return DiagTemplateArg(DB, Arg);
515 }
516 
517 clang::TemplateArgumentLocInfo::TemplateArgumentLocInfo(
518     ASTContext &Ctx, NestedNameSpecifierLoc QualifierLoc,
519     SourceLocation TemplateNameLoc, SourceLocation EllipsisLoc) {
520   TemplateTemplateArgLocInfo *Template = new (Ctx) TemplateTemplateArgLocInfo;
521   Template->Qualifier = QualifierLoc.getNestedNameSpecifier();
522   Template->QualifierLocData = QualifierLoc.getOpaqueData();
523   Template->TemplateNameLoc = TemplateNameLoc.getRawEncoding();
524   Template->EllipsisLoc = EllipsisLoc.getRawEncoding();
525   Pointer = Template;
526 }
527 
528 const ASTTemplateArgumentListInfo *
529 ASTTemplateArgumentListInfo::Create(const ASTContext &C,
530                                     const TemplateArgumentListInfo &List) {
531   std::size_t size = totalSizeToAlloc<TemplateArgumentLoc>(List.size());
532   void *Mem = C.Allocate(size, alignof(ASTTemplateArgumentListInfo));
533   return new (Mem) ASTTemplateArgumentListInfo(List);
534 }
535 
536 ASTTemplateArgumentListInfo::ASTTemplateArgumentListInfo(
537     const TemplateArgumentListInfo &Info) {
538   LAngleLoc = Info.getLAngleLoc();
539   RAngleLoc = Info.getRAngleLoc();
540   NumTemplateArgs = Info.size();
541 
542   TemplateArgumentLoc *ArgBuffer = getTrailingObjects<TemplateArgumentLoc>();
543   for (unsigned i = 0; i != NumTemplateArgs; ++i)
544     new (&ArgBuffer[i]) TemplateArgumentLoc(Info[i]);
545 }
546 
547 void ASTTemplateKWAndArgsInfo::initializeFrom(
548     SourceLocation TemplateKWLoc, const TemplateArgumentListInfo &Info,
549     TemplateArgumentLoc *OutArgArray) {
550   this->TemplateKWLoc = TemplateKWLoc;
551   LAngleLoc = Info.getLAngleLoc();
552   RAngleLoc = Info.getRAngleLoc();
553   NumTemplateArgs = Info.size();
554 
555   for (unsigned i = 0; i != NumTemplateArgs; ++i)
556     new (&OutArgArray[i]) TemplateArgumentLoc(Info[i]);
557 }
558 
559 void ASTTemplateKWAndArgsInfo::initializeFrom(SourceLocation TemplateKWLoc) {
560   assert(TemplateKWLoc.isValid());
561   LAngleLoc = SourceLocation();
562   RAngleLoc = SourceLocation();
563   this->TemplateKWLoc = TemplateKWLoc;
564   NumTemplateArgs = 0;
565 }
566 
567 void ASTTemplateKWAndArgsInfo::initializeFrom(
568     SourceLocation TemplateKWLoc, const TemplateArgumentListInfo &Info,
569     TemplateArgumentLoc *OutArgArray, TemplateArgumentDependence &Deps) {
570   this->TemplateKWLoc = TemplateKWLoc;
571   LAngleLoc = Info.getLAngleLoc();
572   RAngleLoc = Info.getRAngleLoc();
573   NumTemplateArgs = Info.size();
574 
575   for (unsigned i = 0; i != NumTemplateArgs; ++i) {
576     Deps |= Info[i].getArgument().getDependence();
577 
578     new (&OutArgArray[i]) TemplateArgumentLoc(Info[i]);
579   }
580 }
581 
582 void ASTTemplateKWAndArgsInfo::copyInto(const TemplateArgumentLoc *ArgArray,
583                                         TemplateArgumentListInfo &Info) const {
584   Info.setLAngleLoc(LAngleLoc);
585   Info.setRAngleLoc(RAngleLoc);
586   for (unsigned I = 0; I != NumTemplateArgs; ++I)
587     Info.addArgument(ArgArray[I]);
588 }
589