SemaTemplateInstantiateDecl.cpp revision 467b1c9bc1b214ee80ae010df4b4a6d6b1876a03 
1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
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 C++ template instantiation for declarations.
10//
11//===----------------------------------------------------------------------===/
12#include "Sema.h"
13#include "clang/AST/ASTContext.h"
14#include "clang/AST/DeclTemplate.h"
15#include "clang/AST/DeclVisitor.h"
16#include "clang/AST/Expr.h"
17#include "llvm/Support/Compiler.h"
18
19using namespace clang;
20
21namespace {
22  class VISIBILITY_HIDDEN TemplateDeclInstantiator
23    : public DeclVisitor<TemplateDeclInstantiator, Decl *>
24  {
25    Sema &SemaRef;
26    DeclContext *Owner;
27    const TemplateArgument *TemplateArgs;
28    unsigned NumTemplateArgs;
29
30  public:
31    typedef Sema::OwningExprResult OwningExprResult;
32
33    TemplateDeclInstantiator(Sema &SemaRef, DeclContext *Owner,
34                             const TemplateArgument *TemplateArgs,
35                             unsigned NumTemplateArgs)
36      : SemaRef(SemaRef), Owner(Owner), TemplateArgs(TemplateArgs),
37        NumTemplateArgs(NumTemplateArgs) { }
38
39    // FIXME: Once we get closer to completion, replace these
40    // manually-written declarations with automatically-generated ones
41    // from clang/AST/DeclNodes.def.
42    Decl *VisitTypedefDecl(TypedefDecl *D);
43    Decl *VisitFieldDecl(FieldDecl *D);
44    Decl *VisitStaticAssertDecl(StaticAssertDecl *D);
45    Decl *VisitEnumDecl(EnumDecl *D);
46    Decl *VisitCXXMethodDecl(CXXMethodDecl *D);
47    Decl *VisitCXXDestructorDecl(CXXDestructorDecl *D);
48    Decl *VisitParmVarDecl(ParmVarDecl *D);
49    Decl *VisitOriginalParmVarDecl(OriginalParmVarDecl *D);
50    // Base case. FIXME: Remove once we can instantiate everything.
51    Decl *VisitDecl(Decl *) {
52      return 0;
53    }
54  };
55}
56
57Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
58  bool Invalid = false;
59  QualType T = D->getUnderlyingType();
60  if (T->isDependentType()) {
61    T = SemaRef.InstantiateType(T, TemplateArgs, NumTemplateArgs,
62                                D->getLocation(),
63                                D->getDeclName());
64    if (T.isNull()) {
65      Invalid = true;
66      T = SemaRef.Context.IntTy;
67    }
68  }
69
70  // Create the new typedef
71  TypedefDecl *Typedef
72    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocation(),
73                          D->getIdentifier(), T);
74  if (Invalid)
75    Typedef->setInvalidDecl();
76
77  Owner->addDecl(Typedef);
78  return Typedef;
79}
80
81Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
82  bool Invalid = false;
83  QualType T = D->getType();
84  if (T->isDependentType())  {
85    T = SemaRef.InstantiateType(T, TemplateArgs, NumTemplateArgs,
86                                D->getLocation(),
87                                D->getDeclName());
88    if (!T.isNull() && T->isFunctionType()) {
89      // C++ [temp.arg.type]p3:
90      //   If a declaration acquires a function type through a type
91      //   dependent on a template-parameter and this causes a
92      //   declaration that does not use the syntactic form of a
93      //   function declarator to have function type, the program is
94      //   ill-formed.
95      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
96        << T;
97      T = QualType();
98      Invalid = true;
99    }
100  }
101
102  Expr *BitWidth = D->getBitWidth();
103  if (Invalid)
104    BitWidth = 0;
105  else if (BitWidth) {
106    OwningExprResult InstantiatedBitWidth
107      = SemaRef.InstantiateExpr(BitWidth, TemplateArgs, NumTemplateArgs);
108    if (InstantiatedBitWidth.isInvalid()) {
109      Invalid = true;
110      BitWidth = 0;
111    } else
112      BitWidth = (Expr *)InstantiatedBitWidth.release();
113  }
114
115  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(), T,
116                                            cast<RecordDecl>(Owner),
117                                            D->getLocation(),
118                                            D->isMutable(),
119                                            BitWidth,
120                                            D->getAccess(),
121                                            0);
122  if (Field) {
123    if (Invalid)
124      Field->setInvalidDecl();
125
126    Owner->addDecl(Field);
127  }
128
129  return Field;
130}
131
132Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
133  Expr *AssertExpr = D->getAssertExpr();
134
135  OwningExprResult InstantiatedAssertExpr
136    = SemaRef.InstantiateExpr(AssertExpr, TemplateArgs, NumTemplateArgs);
137  if (InstantiatedAssertExpr.isInvalid())
138    return 0;
139
140  OwningExprResult Message = SemaRef.Clone(D->getMessage());
141  Decl *StaticAssert
142    = (Decl *)SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
143                                                move(InstantiatedAssertExpr),
144                                                   move(Message));
145  return StaticAssert;
146}
147
148Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
149  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner,
150                                    D->getLocation(), D->getIdentifier(),
151                                    /*PrevDecl=*/0);
152  Owner->addDecl(Enum);
153  Enum->startDefinition();
154
155  llvm::SmallVector<Sema::DeclTy *, 16> Enumerators;
156
157  EnumConstantDecl *LastEnumConst = 0;
158  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
159         ECEnd = D->enumerator_end();
160       EC != ECEnd; ++EC) {
161    // The specified value for the enumerator.
162    OwningExprResult Value = SemaRef.Owned((Expr *)0);
163    if (Expr *UninstValue = EC->getInitExpr())
164      Value = SemaRef.InstantiateExpr(UninstValue,
165                                      TemplateArgs, NumTemplateArgs);
166
167    // Drop the initial value and continue.
168    bool isInvalid = false;
169    if (Value.isInvalid()) {
170      Value = SemaRef.Owned((Expr *)0);
171      isInvalid = true;
172    }
173
174    EnumConstantDecl *EnumConst
175      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
176                                  EC->getLocation(), EC->getIdentifier(),
177                                  move(Value));
178
179    if (isInvalid) {
180      if (EnumConst)
181        EnumConst->setInvalidDecl();
182      Enum->setInvalidDecl();
183    }
184
185    if (EnumConst) {
186      Enum->addDecl(EnumConst);
187      Enumerators.push_back(EnumConst);
188      LastEnumConst = EnumConst;
189    }
190  }
191
192  SemaRef.ActOnEnumBody(Enum->getLocation(), Enum,
193                        &Enumerators[0], Enumerators.size());
194
195  return Enum;
196}
197
198Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
199  // Only handle actual methods; we'll deal with constructors,
200  // destructors, etc. separately.
201  if (D->getKind() != Decl::CXXMethod)
202    return 0;
203
204  QualType T = SemaRef.InstantiateType(D->getType(), TemplateArgs,
205                                       NumTemplateArgs, D->getLocation(),
206                                       D->getDeclName());
207  if (T.isNull())
208    return 0;
209
210  // Build the instantiated method declaration.
211  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
212  CXXMethodDecl *Method
213    = CXXMethodDecl::Create(SemaRef.Context, Record, D->getLocation(),
214                            D->getDeclName(), T, D->isStatic(),
215                            D->isInline());
216  Method->setAccess(D->getAccess());
217  // FIXME: Duplicates some logic in ActOnFunctionDeclarator.
218  if (D->isVirtual()) {
219    Method->setVirtual();
220    Record->setAggregate(false);
221    Record->setPOD(false);
222    Record->setPolymorphic(true);
223  }
224  if (D->isDeleted())
225    Method->setDeleted();
226  if (D->isPure()) {
227    Method->setPure();
228    Record->setAbstract(true);
229  }
230  // FIXME: attributes
231  // FIXME: Method needs a pointer referencing where it came from.
232
233  // Instantiate the function parameters
234  {
235    TemplateDeclInstantiator ParamInstantiator(SemaRef, Method,
236                                               TemplateArgs, NumTemplateArgs);
237    llvm::SmallVector<ParmVarDecl *, 16> Params;
238    for (FunctionDecl::param_iterator P = Method->param_begin(),
239                                   PEnd = Method->param_end();
240         P != PEnd; ++P) {
241      if (ParmVarDecl *PInst = (ParmVarDecl *)ParamInstantiator.Visit(*P))
242        Params.push_back(PInst);
243      else
244        Method->setInvalidDecl();
245    }
246  }
247
248  NamedDecl *PrevDecl
249    = SemaRef.LookupQualifiedName(Owner, Method->getDeclName(),
250                                  Sema::LookupOrdinaryName, true);
251  // In C++, the previous declaration we find might be a tag type
252  // (class or enum). In this case, the new declaration will hide the
253  // tag type. Note that this does does not apply if we're declaring a
254  // typedef (C++ [dcl.typedef]p4).
255  if (PrevDecl && PrevDecl->getIdentifierNamespace() == Decl::IDNS_Tag)
256    PrevDecl = 0;
257  bool Redeclaration = false;
258  bool OverloadableAttrRequired = false;
259  if (SemaRef.CheckFunctionDeclaration(Method, PrevDecl, Redeclaration,
260                                       /*FIXME:*/OverloadableAttrRequired))
261    Method->setInvalidDecl();
262
263  if (!Method->isInvalidDecl() || !PrevDecl)
264    Owner->addDecl(Method);
265  return Method;
266}
267
268Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
269  QualType T = SemaRef.InstantiateType(D->getType(), TemplateArgs,
270                                       NumTemplateArgs, D->getLocation(),
271                                       D->getDeclName());
272  if (T.isNull())
273    return 0;
274
275  // Build the instantiated destructor declaration.
276  CXXRecordDecl *Record = cast<CXXRecordDecl>(Owner);
277  QualType ClassTy = SemaRef.Context.getTypeDeclType(Record);
278  CXXDestructorDecl *Destructor
279    = CXXDestructorDecl::Create(SemaRef.Context, Record,
280                                D->getLocation(),
281             SemaRef.Context.DeclarationNames.getCXXDestructorName(ClassTy),
282                                T, D->isInline(), false);
283
284  Destructor->setAccess(D->getAccess());
285  // FIXME: Duplicates some logic in ActOnFunctionDeclarator,
286  // VisitCXXDestructorDecl.
287  if (D->isVirtual()) {
288    Destructor->setVirtual();
289    Record->setAggregate(false);
290    Record->setPOD(false);
291    Record->setPolymorphic(true);
292  }
293  if (D->isDeleted())
294    Destructor->setDeleted();
295  if (D->isPure()) {
296    Destructor->setPure();
297    Record->setAbstract(true);
298  }
299
300  bool Redeclaration = false;
301  bool OverloadableAttrRequired = false;
302  NamedDecl *PrevDecl = 0;
303  if (SemaRef.CheckFunctionDeclaration(Destructor, PrevDecl, Redeclaration,
304                                       /*FIXME:*/OverloadableAttrRequired))
305    Destructor->setInvalidDecl();
306  Owner->addDecl(Destructor);
307  return Destructor;
308}
309
310Decl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
311  QualType OrigT = SemaRef.InstantiateType(D->getOriginalType(), TemplateArgs,
312                                           NumTemplateArgs, D->getLocation(),
313                                           D->getDeclName());
314  if (OrigT.isNull())
315    return 0;
316
317  QualType T = SemaRef.adjustParameterType(OrigT);
318
319  if (D->getDefaultArg()) {
320    // FIXME: Leave a marker for "uninstantiated" default
321    // arguments. They only get instantiated on demand at the call
322    // site.
323    unsigned DiagID = SemaRef.Diags.getCustomDiagID(Diagnostic::Warning,
324        "sorry, dropping default argument during template instantiation");
325    SemaRef.Diag(D->getDefaultArg()->getSourceRange().getBegin(), DiagID)
326      << D->getDefaultArg()->getSourceRange();
327  }
328
329  // Allocate the parameter
330  ParmVarDecl *Param = 0;
331  if (T == OrigT)
332    Param = ParmVarDecl::Create(SemaRef.Context, Owner, D->getLocation(),
333                                D->getIdentifier(), T, D->getStorageClass(),
334                                0);
335  else
336    Param = OriginalParmVarDecl::Create(SemaRef.Context, Owner,
337                                        D->getLocation(), D->getIdentifier(),
338                                        T, OrigT, D->getStorageClass(), 0);
339
340  // Note: we don't try to instantiate function parameters until after
341  // we've instantiated the function's type. Therefore, we don't have
342  // to check for 'void' parameter types here.
343  return Param;
344}
345
346Decl *
347TemplateDeclInstantiator::VisitOriginalParmVarDecl(OriginalParmVarDecl *D) {
348  // Since parameter types can decay either before or after
349  // instantiation, we simply treat OriginalParmVarDecls as
350  // ParmVarDecls the same way, and create one or the other depending
351  // on what happens after template instantiation.
352  return VisitParmVarDecl(D);
353}
354
355Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
356                            const TemplateArgument *TemplateArgs,
357                            unsigned NumTemplateArgs) {
358  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs,
359                                        NumTemplateArgs);
360  return Instantiator.Visit(D);
361}
362
363