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     Out << '&';
356     if (ND->getDeclName()) {
357       // FIXME: distinguish between pointer and reference args?
358       ND->printQualifiedName(Out);
359     } else {
360       Out << "(anonymous)";
361     }
362     break;
363   }
364 
365   case NullPtr:
366     Out << "nullptr";
367     break;
368 
369   case Template:
370     getAsTemplate().print(Out, Policy);
371     break;
372 
373   case TemplateExpansion:
374     getAsTemplateOrTemplatePattern().print(Out, Policy);
375     Out << "...";
376     break;
377 
378   case Integral:
379     printIntegral(*this, Out, Policy);
380     break;
381 
382   case Expression:
383     getAsExpr()->printPretty(Out, nullptr, Policy);
384     break;
385 
386   case Pack:
387     Out << "<";
388     bool First = true;
389     for (const auto &P : pack_elements()) {
390       if (First)
391         First = false;
392       else
393         Out << ", ";
394 
395       P.print(Policy, Out);
396     }
397     Out << ">";
398     break;
399   }
400 }
401 
402 void TemplateArgument::dump(raw_ostream &Out) const {
403   LangOptions LO; // FIXME! see also TemplateName::dump().
404   LO.CPlusPlus = true;
405   LO.Bool = true;
406   print(PrintingPolicy(LO), Out);
407 }
408 
409 LLVM_DUMP_METHOD void TemplateArgument::dump() const { dump(llvm::errs()); }
410 
411 //===----------------------------------------------------------------------===//
412 // TemplateArgumentLoc Implementation
413 //===----------------------------------------------------------------------===//
414 
415 SourceRange TemplateArgumentLoc::getSourceRange() const {
416   switch (Argument.getKind()) {
417   case TemplateArgument::Expression:
418     return getSourceExpression()->getSourceRange();
419 
420   case TemplateArgument::Declaration:
421     return getSourceDeclExpression()->getSourceRange();
422 
423   case TemplateArgument::NullPtr:
424     return getSourceNullPtrExpression()->getSourceRange();
425 
426   case TemplateArgument::Type:
427     if (TypeSourceInfo *TSI = getTypeSourceInfo())
428       return TSI->getTypeLoc().getSourceRange();
429     else
430       return SourceRange();
431 
432   case TemplateArgument::Template:
433     if (getTemplateQualifierLoc())
434       return SourceRange(getTemplateQualifierLoc().getBeginLoc(),
435                          getTemplateNameLoc());
436     return SourceRange(getTemplateNameLoc());
437 
438   case TemplateArgument::TemplateExpansion:
439     if (getTemplateQualifierLoc())
440       return SourceRange(getTemplateQualifierLoc().getBeginLoc(),
441                          getTemplateEllipsisLoc());
442     return SourceRange(getTemplateNameLoc(), getTemplateEllipsisLoc());
443 
444   case TemplateArgument::Integral:
445     return getSourceIntegralExpression()->getSourceRange();
446 
447   case TemplateArgument::Pack:
448   case TemplateArgument::Null:
449     return SourceRange();
450   }
451 
452   llvm_unreachable("Invalid TemplateArgument Kind!");
453 }
454 
455 const DiagnosticBuilder &clang::operator<<(const DiagnosticBuilder &DB,
456                                            const TemplateArgument &Arg) {
457   switch (Arg.getKind()) {
458   case TemplateArgument::Null:
459     // This is bad, but not as bad as crashing because of argument
460     // count mismatches.
461     return DB << "(null template argument)";
462 
463   case TemplateArgument::Type:
464     return DB << Arg.getAsType();
465 
466   case TemplateArgument::Declaration:
467     return DB << Arg.getAsDecl();
468 
469   case TemplateArgument::NullPtr:
470     return DB << "nullptr";
471 
472   case TemplateArgument::Integral:
473     return DB << Arg.getAsIntegral().toString(10);
474 
475   case TemplateArgument::Template:
476     return DB << Arg.getAsTemplate();
477 
478   case TemplateArgument::TemplateExpansion:
479     return DB << Arg.getAsTemplateOrTemplatePattern() << "...";
480 
481   case TemplateArgument::Expression: {
482     // This shouldn't actually ever happen, so it's okay that we're
483     // regurgitating an expression here.
484     // FIXME: We're guessing at LangOptions!
485     SmallString<32> Str;
486     llvm::raw_svector_ostream OS(Str);
487     LangOptions LangOpts;
488     LangOpts.CPlusPlus = true;
489     PrintingPolicy Policy(LangOpts);
490     Arg.getAsExpr()->printPretty(OS, nullptr, Policy);
491     return DB << OS.str();
492   }
493 
494   case TemplateArgument::Pack: {
495     // FIXME: We're guessing at LangOptions!
496     SmallString<32> Str;
497     llvm::raw_svector_ostream OS(Str);
498     LangOptions LangOpts;
499     LangOpts.CPlusPlus = true;
500     PrintingPolicy Policy(LangOpts);
501     Arg.print(Policy, OS);
502     return DB << OS.str();
503   }
504   }
505 
506   llvm_unreachable("Invalid TemplateArgument Kind!");
507 }
508 
509 const ASTTemplateArgumentListInfo *
510 ASTTemplateArgumentListInfo::Create(const ASTContext &C,
511                                     const TemplateArgumentListInfo &List) {
512   std::size_t size = totalSizeToAlloc<TemplateArgumentLoc>(List.size());
513   void *Mem = C.Allocate(size, alignof(ASTTemplateArgumentListInfo));
514   return new (Mem) ASTTemplateArgumentListInfo(List);
515 }
516 
517 ASTTemplateArgumentListInfo::ASTTemplateArgumentListInfo(
518     const TemplateArgumentListInfo &Info) {
519   LAngleLoc = Info.getLAngleLoc();
520   RAngleLoc = Info.getRAngleLoc();
521   NumTemplateArgs = Info.size();
522 
523   TemplateArgumentLoc *ArgBuffer = getTrailingObjects<TemplateArgumentLoc>();
524   for (unsigned i = 0; i != NumTemplateArgs; ++i)
525     new (&ArgBuffer[i]) TemplateArgumentLoc(Info[i]);
526 }
527 
528 void ASTTemplateKWAndArgsInfo::initializeFrom(
529     SourceLocation TemplateKWLoc, const TemplateArgumentListInfo &Info,
530     TemplateArgumentLoc *OutArgArray) {
531   this->TemplateKWLoc = TemplateKWLoc;
532   LAngleLoc = Info.getLAngleLoc();
533   RAngleLoc = Info.getRAngleLoc();
534   NumTemplateArgs = Info.size();
535 
536   for (unsigned i = 0; i != NumTemplateArgs; ++i)
537     new (&OutArgArray[i]) TemplateArgumentLoc(Info[i]);
538 }
539 
540 void ASTTemplateKWAndArgsInfo::initializeFrom(SourceLocation TemplateKWLoc) {
541   assert(TemplateKWLoc.isValid());
542   LAngleLoc = SourceLocation();
543   RAngleLoc = SourceLocation();
544   this->TemplateKWLoc = TemplateKWLoc;
545   NumTemplateArgs = 0;
546 }
547 
548 void ASTTemplateKWAndArgsInfo::initializeFrom(
549     SourceLocation TemplateKWLoc, const TemplateArgumentListInfo &Info,
550     TemplateArgumentLoc *OutArgArray, TemplateArgumentDependence &Deps) {
551   this->TemplateKWLoc = TemplateKWLoc;
552   LAngleLoc = Info.getLAngleLoc();
553   RAngleLoc = Info.getRAngleLoc();
554   NumTemplateArgs = Info.size();
555 
556   for (unsigned i = 0; i != NumTemplateArgs; ++i) {
557     Deps |= Info[i].getArgument().getDependence();
558 
559     new (&OutArgArray[i]) TemplateArgumentLoc(Info[i]);
560   }
561 }
562 
563 void ASTTemplateKWAndArgsInfo::copyInto(const TemplateArgumentLoc *ArgArray,
564                                         TemplateArgumentListInfo &Info) const {
565   Info.setLAngleLoc(LAngleLoc);
566   Info.setRAngleLoc(RAngleLoc);
567   for (unsigned I = 0; I != NumTemplateArgs; ++I)
568     Info.addArgument(ArgArray[I]);
569 }
570