1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
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 //
10 //  This file implements serialization for Declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Serialization/ASTWriter.h"
15 #include "clang/AST/DeclVisitor.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/DeclTemplate.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/DeclContextInternals.h"
20 #include "llvm/ADT/Twine.h"
21 #include "llvm/Bitcode/BitstreamWriter.h"
22 #include "llvm/Support/ErrorHandling.h"
23 using namespace clang;
24 
25 //===----------------------------------------------------------------------===//
26 // Declaration serialization
27 //===----------------------------------------------------------------------===//
28 
29 namespace clang {
30   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
31 
32     ASTWriter &Writer;
33     ASTContext &Context;
34     typedef ASTWriter::RecordData RecordData;
35     RecordData &Record;
36 
37   public:
38     serialization::DeclCode Code;
39     unsigned AbbrevToUse;
40 
41     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context, RecordData &Record)
42       : Writer(Writer), Context(Context), Record(Record) {
43     }
44 
45     void Visit(Decl *D);
46 
47     void VisitDecl(Decl *D);
48     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
49     void VisitNamedDecl(NamedDecl *D);
50     void VisitNamespaceDecl(NamespaceDecl *D);
51     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
52     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
53     void VisitTypeDecl(TypeDecl *D);
54     void VisitTypedefDecl(TypedefDecl *D);
55     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
56     void VisitTagDecl(TagDecl *D);
57     void VisitEnumDecl(EnumDecl *D);
58     void VisitRecordDecl(RecordDecl *D);
59     void VisitCXXRecordDecl(CXXRecordDecl *D);
60     void VisitClassTemplateSpecializationDecl(
61                                             ClassTemplateSpecializationDecl *D);
62     void VisitClassTemplatePartialSpecializationDecl(
63                                      ClassTemplatePartialSpecializationDecl *D);
64     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
65     void VisitValueDecl(ValueDecl *D);
66     void VisitEnumConstantDecl(EnumConstantDecl *D);
67     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
68     void VisitDeclaratorDecl(DeclaratorDecl *D);
69     void VisitFunctionDecl(FunctionDecl *D);
70     void VisitCXXMethodDecl(CXXMethodDecl *D);
71     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
72     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
73     void VisitCXXConversionDecl(CXXConversionDecl *D);
74     void VisitFieldDecl(FieldDecl *D);
75     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
76     void VisitVarDecl(VarDecl *D);
77     void VisitImplicitParamDecl(ImplicitParamDecl *D);
78     void VisitParmVarDecl(ParmVarDecl *D);
79     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
80     void VisitTemplateDecl(TemplateDecl *D);
81     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
82     void VisitClassTemplateDecl(ClassTemplateDecl *D);
83     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
84     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
85     void VisitUsingDecl(UsingDecl *D);
86     void VisitUsingShadowDecl(UsingShadowDecl *D);
87     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
88     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
89     void VisitAccessSpecDecl(AccessSpecDecl *D);
90     void VisitFriendDecl(FriendDecl *D);
91     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
92     void VisitStaticAssertDecl(StaticAssertDecl *D);
93     void VisitBlockDecl(BlockDecl *D);
94 
95     void VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
96                           uint64_t VisibleOffset);
97     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
98 
99 
100     // FIXME: Put in the same order is DeclNodes.td?
101     void VisitObjCMethodDecl(ObjCMethodDecl *D);
102     void VisitObjCContainerDecl(ObjCContainerDecl *D);
103     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
104     void VisitObjCIvarDecl(ObjCIvarDecl *D);
105     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
106     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
107     void VisitObjCClassDecl(ObjCClassDecl *D);
108     void VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *D);
109     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
110     void VisitObjCImplDecl(ObjCImplDecl *D);
111     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
112     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
113     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
114     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
115     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
116   };
117 }
118 
119 void ASTDeclWriter::Visit(Decl *D) {
120   DeclVisitor<ASTDeclWriter>::Visit(D);
121 
122   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
123   // have been written. We want it last because we will not read it back when
124   // retrieving it from the AST, we'll just lazily set the offset.
125   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
126     Record.push_back(FD->isThisDeclarationADefinition());
127     if (FD->isThisDeclarationADefinition())
128       Writer.AddStmt(FD->getBody());
129   }
130 }
131 
132 void ASTDeclWriter::VisitDecl(Decl *D) {
133   Writer.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()), Record);
134   Writer.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()), Record);
135   Writer.AddSourceLocation(D->getLocation(), Record);
136   Record.push_back(D->isInvalidDecl());
137   Record.push_back(D->hasAttrs());
138   if (D->hasAttrs())
139     Writer.WriteAttributes(D->getAttrs(), Record);
140   Record.push_back(D->isImplicit());
141   Record.push_back(D->isUsed(false));
142   Record.push_back(D->getAccess());
143   Record.push_back(D->getPCHLevel());
144 }
145 
146 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
147   VisitDecl(D);
148   Writer.AddDeclRef(D->getAnonymousNamespace(), Record);
149   Code = serialization::DECL_TRANSLATION_UNIT;
150 }
151 
152 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
153   VisitDecl(D);
154   Writer.AddDeclarationName(D->getDeclName(), Record);
155 }
156 
157 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
158   VisitNamedDecl(D);
159   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);
160 }
161 
162 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
163   VisitTypeDecl(D);
164   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
165   Code = serialization::DECL_TYPEDEF;
166 }
167 
168 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
169   VisitTypeDecl(D);
170   VisitRedeclarable(D);
171   Record.push_back(D->getIdentifierNamespace());
172   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
173   Record.push_back(D->isDefinition());
174   Record.push_back(D->isEmbeddedInDeclarator());
175   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
176   Writer.AddSourceLocation(D->getTagKeywordLoc(), Record);
177   Record.push_back(D->hasExtInfo());
178   if (D->hasExtInfo())
179     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
180   else
181     Writer.AddDeclRef(D->getTypedefForAnonDecl(), Record);
182 }
183 
184 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
185   VisitTagDecl(D);
186   Writer.AddTypeSourceInfo(D->getIntegerTypeSourceInfo(), Record);
187   if (!D->getIntegerTypeSourceInfo())
188     Writer.AddTypeRef(D->getIntegerType(), Record);
189   Writer.AddTypeRef(D->getPromotionType(), Record);
190   Record.push_back(D->getNumPositiveBits());
191   Record.push_back(D->getNumNegativeBits());
192   Record.push_back(D->isScoped());
193   Record.push_back(D->isScopedUsingClassTag());
194   Record.push_back(D->isFixed());
195   Writer.AddDeclRef(D->getInstantiatedFromMemberEnum(), Record);
196   Code = serialization::DECL_ENUM;
197 }
198 
199 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
200   VisitTagDecl(D);
201   Record.push_back(D->hasFlexibleArrayMember());
202   Record.push_back(D->isAnonymousStructOrUnion());
203   Record.push_back(D->hasObjectMember());
204   Code = serialization::DECL_RECORD;
205 }
206 
207 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
208   VisitNamedDecl(D);
209   Writer.AddTypeRef(D->getType(), Record);
210 }
211 
212 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
213   VisitValueDecl(D);
214   Record.push_back(D->getInitExpr()? 1 : 0);
215   if (D->getInitExpr())
216     Writer.AddStmt(D->getInitExpr());
217   Writer.AddAPSInt(D->getInitVal(), Record);
218   Code = serialization::DECL_ENUM_CONSTANT;
219 }
220 
221 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
222   VisitValueDecl(D);
223   Record.push_back(D->hasExtInfo());
224   if (D->hasExtInfo())
225     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
226   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
227 }
228 
229 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
230   VisitDeclaratorDecl(D);
231   VisitRedeclarable(D);
232 
233   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
234   Record.push_back(D->getIdentifierNamespace());
235   Record.push_back(D->getTemplatedKind());
236   switch (D->getTemplatedKind()) {
237   default: assert(false && "Unhandled TemplatedKind!");
238     break;
239   case FunctionDecl::TK_NonTemplate:
240     break;
241   case FunctionDecl::TK_FunctionTemplate:
242     Writer.AddDeclRef(D->getDescribedFunctionTemplate(), Record);
243     break;
244   case FunctionDecl::TK_MemberSpecialization: {
245     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
246     Writer.AddDeclRef(MemberInfo->getInstantiatedFrom(), Record);
247     Record.push_back(MemberInfo->getTemplateSpecializationKind());
248     Writer.AddSourceLocation(MemberInfo->getPointOfInstantiation(), Record);
249     break;
250   }
251   case FunctionDecl::TK_FunctionTemplateSpecialization: {
252     FunctionTemplateSpecializationInfo *
253       FTSInfo = D->getTemplateSpecializationInfo();
254     Writer.AddDeclRef(FTSInfo->getTemplate(), Record);
255     Record.push_back(FTSInfo->getTemplateSpecializationKind());
256 
257     // Template arguments.
258     Writer.AddTemplateArgumentList(FTSInfo->TemplateArguments, Record);
259 
260     // Template args as written.
261     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != 0);
262     if (FTSInfo->TemplateArgumentsAsWritten) {
263       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->size());
264       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->size(); i!=e; ++i)
265         Writer.AddTemplateArgumentLoc((*FTSInfo->TemplateArgumentsAsWritten)[i],
266                                       Record);
267       Writer.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->getLAngleLoc(),
268                                Record);
269       Writer.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->getRAngleLoc(),
270                                Record);
271     }
272 
273     Writer.AddSourceLocation(FTSInfo->getPointOfInstantiation(), Record);
274 
275     if (D->isCanonicalDecl()) {
276       // Write the template that contains the specializations set. We will
277       // add a FunctionTemplateSpecializationInfo to it when reading.
278       Writer.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl(), Record);
279     }
280     break;
281   }
282   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
283     DependentFunctionTemplateSpecializationInfo *
284       DFTSInfo = D->getDependentSpecializationInfo();
285 
286     // Templates.
287     Record.push_back(DFTSInfo->getNumTemplates());
288     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
289       Writer.AddDeclRef(DFTSInfo->getTemplate(i), Record);
290 
291     // Templates args.
292     Record.push_back(DFTSInfo->getNumTemplateArgs());
293     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
294       Writer.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i), Record);
295     Writer.AddSourceLocation(DFTSInfo->getLAngleLoc(), Record);
296     Writer.AddSourceLocation(DFTSInfo->getRAngleLoc(), Record);
297     break;
298   }
299   }
300 
301   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
302   // after everything else is written.
303 
304   Record.push_back(D->getStorageClass()); // FIXME: stable encoding
305   Record.push_back(D->getStorageClassAsWritten());
306   Record.push_back(D->IsInline);
307   Record.push_back(D->isInlineSpecified());
308   Record.push_back(D->isVirtualAsWritten());
309   Record.push_back(D->isPure());
310   Record.push_back(D->hasInheritedPrototype());
311   Record.push_back(D->hasWrittenPrototype());
312   Record.push_back(D->isDeleted());
313   Record.push_back(D->isTrivial());
314   Record.push_back(D->hasImplicitReturnZero());
315   Writer.AddSourceLocation(D->getLocEnd(), Record);
316 
317   Record.push_back(D->param_size());
318   for (FunctionDecl::param_iterator P = D->param_begin(), PEnd = D->param_end();
319        P != PEnd; ++P)
320     Writer.AddDeclRef(*P, Record);
321   Code = serialization::DECL_FUNCTION;
322 }
323 
324 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
325   VisitNamedDecl(D);
326   // FIXME: convert to LazyStmtPtr?
327   // Unlike C/C++, method bodies will never be in header files.
328   bool HasBodyStuff = D->getBody() != 0     ||
329                       D->getSelfDecl() != 0 || D->getCmdDecl() != 0;
330   Record.push_back(HasBodyStuff);
331   if (HasBodyStuff) {
332     Writer.AddStmt(D->getBody());
333     Writer.AddDeclRef(D->getSelfDecl(), Record);
334     Writer.AddDeclRef(D->getCmdDecl(), Record);
335   }
336   Record.push_back(D->isInstanceMethod());
337   Record.push_back(D->isVariadic());
338   Record.push_back(D->isSynthesized());
339   Record.push_back(D->isDefined());
340   // FIXME: stable encoding for @required/@optional
341   Record.push_back(D->getImplementationControl());
342   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway
343   Record.push_back(D->getObjCDeclQualifier());
344   Record.push_back(D->getNumSelectorArgs());
345   Writer.AddTypeRef(D->getResultType(), Record);
346   Writer.AddTypeSourceInfo(D->getResultTypeSourceInfo(), Record);
347   Writer.AddSourceLocation(D->getLocEnd(), Record);
348   Record.push_back(D->param_size());
349   for (ObjCMethodDecl::param_iterator P = D->param_begin(),
350                                    PEnd = D->param_end(); P != PEnd; ++P)
351     Writer.AddDeclRef(*P, Record);
352   Code = serialization::DECL_OBJC_METHOD;
353 }
354 
355 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
356   VisitNamedDecl(D);
357   Writer.AddSourceRange(D->getAtEndRange(), Record);
358   // Abstract class (no need to define a stable serialization::DECL code).
359 }
360 
361 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
362   VisitObjCContainerDecl(D);
363   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);
364   Writer.AddDeclRef(D->getSuperClass(), Record);
365 
366   // Write out the protocols that are directly referenced by the @interface.
367   Record.push_back(D->ReferencedProtocols.size());
368   for (ObjCInterfaceDecl::protocol_iterator P = D->protocol_begin(),
369          PEnd = D->protocol_end();
370        P != PEnd; ++P)
371     Writer.AddDeclRef(*P, Record);
372   for (ObjCInterfaceDecl::protocol_loc_iterator PL = D->protocol_loc_begin(),
373          PLEnd = D->protocol_loc_end();
374        PL != PLEnd; ++PL)
375     Writer.AddSourceLocation(*PL, Record);
376 
377   // Write out the protocols that are transitively referenced.
378   Record.push_back(D->AllReferencedProtocols.size());
379   for (ObjCList<ObjCProtocolDecl>::iterator
380         P = D->AllReferencedProtocols.begin(),
381         PEnd = D->AllReferencedProtocols.end();
382        P != PEnd; ++P)
383     Writer.AddDeclRef(*P, Record);
384 
385   // Write out the ivars.
386   Record.push_back(D->ivar_size());
387   for (ObjCInterfaceDecl::ivar_iterator I = D->ivar_begin(),
388                                      IEnd = D->ivar_end(); I != IEnd; ++I)
389     Writer.AddDeclRef(*I, Record);
390   Writer.AddDeclRef(D->getCategoryList(), Record);
391   Record.push_back(D->isForwardDecl());
392   Record.push_back(D->isImplicitInterfaceDecl());
393   Writer.AddSourceLocation(D->getClassLoc(), Record);
394   Writer.AddSourceLocation(D->getSuperClassLoc(), Record);
395   Writer.AddSourceLocation(D->getLocEnd(), Record);
396   Code = serialization::DECL_OBJC_INTERFACE;
397 }
398 
399 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
400   VisitFieldDecl(D);
401   // FIXME: stable encoding for @public/@private/@protected/@package
402   Record.push_back(D->getAccessControl());
403   Record.push_back(D->getSynthesize());
404   Code = serialization::DECL_OBJC_IVAR;
405 }
406 
407 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
408   VisitObjCContainerDecl(D);
409   Record.push_back(D->isForwardDecl());
410   Writer.AddSourceLocation(D->getLocEnd(), Record);
411   Record.push_back(D->protocol_size());
412   for (ObjCProtocolDecl::protocol_iterator
413        I = D->protocol_begin(), IEnd = D->protocol_end(); I != IEnd; ++I)
414     Writer.AddDeclRef(*I, Record);
415   for (ObjCProtocolDecl::protocol_loc_iterator PL = D->protocol_loc_begin(),
416          PLEnd = D->protocol_loc_end();
417        PL != PLEnd; ++PL)
418     Writer.AddSourceLocation(*PL, Record);
419   Code = serialization::DECL_OBJC_PROTOCOL;
420 }
421 
422 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
423   VisitFieldDecl(D);
424   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
425 }
426 
427 void ASTDeclWriter::VisitObjCClassDecl(ObjCClassDecl *D) {
428   VisitDecl(D);
429   Record.push_back(D->size());
430   for (ObjCClassDecl::iterator I = D->begin(), IEnd = D->end(); I != IEnd; ++I)
431     Writer.AddDeclRef(I->getInterface(), Record);
432   for (ObjCClassDecl::iterator I = D->begin(), IEnd = D->end(); I != IEnd; ++I)
433     Writer.AddSourceLocation(I->getLocation(), Record);
434   Code = serialization::DECL_OBJC_CLASS;
435 }
436 
437 void ASTDeclWriter::VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *D) {
438   VisitDecl(D);
439   Record.push_back(D->protocol_size());
440   for (ObjCForwardProtocolDecl::protocol_iterator
441        I = D->protocol_begin(), IEnd = D->protocol_end(); I != IEnd; ++I)
442     Writer.AddDeclRef(*I, Record);
443   for (ObjCForwardProtocolDecl::protocol_loc_iterator
444          PL = D->protocol_loc_begin(), PLEnd = D->protocol_loc_end();
445        PL != PLEnd; ++PL)
446     Writer.AddSourceLocation(*PL, Record);
447   Code = serialization::DECL_OBJC_FORWARD_PROTOCOL;
448 }
449 
450 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
451   VisitObjCContainerDecl(D);
452   Writer.AddDeclRef(D->getClassInterface(), Record);
453   Record.push_back(D->protocol_size());
454   for (ObjCCategoryDecl::protocol_iterator
455        I = D->protocol_begin(), IEnd = D->protocol_end(); I != IEnd; ++I)
456     Writer.AddDeclRef(*I, Record);
457   for (ObjCCategoryDecl::protocol_loc_iterator
458          PL = D->protocol_loc_begin(), PLEnd = D->protocol_loc_end();
459        PL != PLEnd; ++PL)
460     Writer.AddSourceLocation(*PL, Record);
461   Writer.AddDeclRef(D->getNextClassCategory(), Record);
462   Record.push_back(D->hasSynthBitfield());
463   Writer.AddSourceLocation(D->getAtLoc(), Record);
464   Writer.AddSourceLocation(D->getCategoryNameLoc(), Record);
465   Code = serialization::DECL_OBJC_CATEGORY;
466 }
467 
468 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
469   VisitNamedDecl(D);
470   Writer.AddDeclRef(D->getClassInterface(), Record);
471   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
472 }
473 
474 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
475   VisitNamedDecl(D);
476   Writer.AddSourceLocation(D->getAtLoc(), Record);
477   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
478   // FIXME: stable encoding
479   Record.push_back((unsigned)D->getPropertyAttributes());
480   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
481   // FIXME: stable encoding
482   Record.push_back((unsigned)D->getPropertyImplementation());
483   Writer.AddDeclarationName(D->getGetterName(), Record);
484   Writer.AddDeclarationName(D->getSetterName(), Record);
485   Writer.AddDeclRef(D->getGetterMethodDecl(), Record);
486   Writer.AddDeclRef(D->getSetterMethodDecl(), Record);
487   Writer.AddDeclRef(D->getPropertyIvarDecl(), Record);
488   Code = serialization::DECL_OBJC_PROPERTY;
489 }
490 
491 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
492   VisitObjCContainerDecl(D);
493   Writer.AddDeclRef(D->getClassInterface(), Record);
494   // Abstract class (no need to define a stable serialization::DECL code).
495 }
496 
497 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
498   VisitObjCImplDecl(D);
499   Writer.AddIdentifierRef(D->getIdentifier(), Record);
500   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
501 }
502 
503 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
504   VisitObjCImplDecl(D);
505   Writer.AddDeclRef(D->getSuperClass(), Record);
506   Writer.AddCXXCtorInitializers(D->IvarInitializers, D->NumIvarInitializers,
507                                 Record);
508   Record.push_back(D->hasSynthBitfield());
509   Code = serialization::DECL_OBJC_IMPLEMENTATION;
510 }
511 
512 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
513   VisitDecl(D);
514   Writer.AddSourceLocation(D->getLocStart(), Record);
515   Writer.AddDeclRef(D->getPropertyDecl(), Record);
516   Writer.AddDeclRef(D->getPropertyIvarDecl(), Record);
517   Writer.AddSourceLocation(D->getPropertyIvarDeclLoc(), Record);
518   Writer.AddStmt(D->getGetterCXXConstructor());
519   Writer.AddStmt(D->getSetterCXXAssignment());
520   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
521 }
522 
523 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
524   VisitDeclaratorDecl(D);
525   Record.push_back(D->isMutable());
526   Record.push_back(D->getBitWidth()? 1 : 0);
527   if (D->getBitWidth())
528     Writer.AddStmt(D->getBitWidth());
529   if (!D->getDeclName())
530     Writer.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D), Record);
531   Code = serialization::DECL_FIELD;
532 }
533 
534 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
535   VisitValueDecl(D);
536   Record.push_back(D->getChainingSize());
537 
538   for (IndirectFieldDecl::chain_iterator
539        P = D->chain_begin(),
540        PEnd = D->chain_end(); P != PEnd; ++P)
541     Writer.AddDeclRef(*P, Record);
542   Code = serialization::DECL_INDIRECTFIELD;
543 }
544 
545 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
546   VisitDeclaratorDecl(D);
547   VisitRedeclarable(D);
548   Record.push_back(D->getStorageClass()); // FIXME: stable encoding
549   Record.push_back(D->getStorageClassAsWritten());
550   Record.push_back(D->isThreadSpecified());
551   Record.push_back(D->hasCXXDirectInitializer());
552   Record.push_back(D->isExceptionVariable());
553   Record.push_back(D->isNRVOVariable());
554   Record.push_back(D->getInit() ? 1 : 0);
555   if (D->getInit())
556     Writer.AddStmt(D->getInit());
557 
558   MemberSpecializationInfo *SpecInfo
559     = D->isStaticDataMember() ? D->getMemberSpecializationInfo() : 0;
560   Record.push_back(SpecInfo != 0);
561   if (SpecInfo) {
562     Writer.AddDeclRef(SpecInfo->getInstantiatedFrom(), Record);
563     Record.push_back(SpecInfo->getTemplateSpecializationKind());
564     Writer.AddSourceLocation(SpecInfo->getPointOfInstantiation(), Record);
565   }
566 
567   Code = serialization::DECL_VAR;
568 }
569 
570 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
571   VisitVarDecl(D);
572   Code = serialization::DECL_IMPLICIT_PARAM;
573 }
574 
575 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
576   VisitVarDecl(D);
577   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
578   Record.push_back(D->hasInheritedDefaultArg());
579   Record.push_back(D->hasUninstantiatedDefaultArg());
580   if (D->hasUninstantiatedDefaultArg())
581     Writer.AddStmt(D->getUninstantiatedDefaultArg());
582   Code = serialization::DECL_PARM_VAR;
583 
584   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
585   // we dynamically check for the properties that we optimize for, but don't
586   // know are true of all PARM_VAR_DECLs.
587   if (!D->getTypeSourceInfo() &&
588       !D->hasAttrs() &&
589       !D->isImplicit() &&
590       !D->isUsed(false) &&
591       D->getAccess() == AS_none &&
592       D->getPCHLevel() == 0 &&
593       D->getStorageClass() == 0 &&
594       !D->hasCXXDirectInitializer() && // Can params have this ever?
595       D->getObjCDeclQualifier() == 0 &&
596       !D->hasInheritedDefaultArg() &&
597       D->getInit() == 0 &&
598       !D->hasUninstantiatedDefaultArg())  // No default expr.
599     AbbrevToUse = Writer.getParmVarDeclAbbrev();
600 
601   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
602   // just us assuming it.
603   assert(!D->isInvalidDecl() && "Shouldn't emit invalid decls");
604   assert(!D->isThreadSpecified() && "PARM_VAR_DECL can't be __thread");
605   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
606   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
607   assert(D->getPreviousDeclaration() == 0 && "PARM_VAR_DECL can't be redecl");
608   assert(!D->isStaticDataMember() &&
609          "PARM_VAR_DECL can't be static data member");
610 }
611 
612 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
613   VisitDecl(D);
614   Writer.AddStmt(D->getAsmString());
615   Code = serialization::DECL_FILE_SCOPE_ASM;
616 }
617 
618 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
619   VisitDecl(D);
620   Writer.AddStmt(D->getBody());
621   Writer.AddTypeSourceInfo(D->getSignatureAsWritten(), Record);
622   Record.push_back(D->param_size());
623   for (FunctionDecl::param_iterator P = D->param_begin(), PEnd = D->param_end();
624        P != PEnd; ++P)
625     Writer.AddDeclRef(*P, Record);
626   Code = serialization::DECL_BLOCK;
627 }
628 
629 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
630   VisitDecl(D);
631   // FIXME: It might be nice to serialize the brace locations for this
632   // declaration, which don't seem to be readily available in the AST.
633   Record.push_back(D->getLanguage());
634   Record.push_back(D->hasBraces());
635   Code = serialization::DECL_LINKAGE_SPEC;
636 }
637 
638 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
639   VisitNamedDecl(D);
640   Record.push_back(D->isInline());
641   Writer.AddSourceLocation(D->getLBracLoc(), Record);
642   Writer.AddSourceLocation(D->getRBracLoc(), Record);
643   Writer.AddDeclRef(D->getNextNamespace(), Record);
644 
645   // Only write one reference--original or anonymous
646   Record.push_back(D->isOriginalNamespace());
647   if (D->isOriginalNamespace())
648     Writer.AddDeclRef(D->getAnonymousNamespace(), Record);
649   else
650     Writer.AddDeclRef(D->getOriginalNamespace(), Record);
651   Code = serialization::DECL_NAMESPACE;
652 
653   if (Writer.hasChain() && !D->isOriginalNamespace() &&
654       D->getOriginalNamespace()->getPCHLevel() > 0) {
655     NamespaceDecl *NS = D->getOriginalNamespace();
656     Writer.AddUpdatedDeclContext(NS);
657 
658     // Make sure all visible decls are written. They will be recorded later.
659     NS->lookup(DeclarationName());
660     StoredDeclsMap *Map = static_cast<StoredDeclsMap*>(NS->getLookupPtr());
661     if (Map) {
662       for (StoredDeclsMap::iterator D = Map->begin(), DEnd = Map->end();
663            D != DEnd; ++D) {
664         DeclarationName Name = D->first;
665         DeclContext::lookup_result Result = D->second.getLookupResult();
666         while (Result.first != Result.second) {
667           Writer.GetDeclRef(*Result.first);
668           ++Result.first;
669         }
670       }
671     }
672   }
673 }
674 
675 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
676   VisitNamedDecl(D);
677   Writer.AddSourceLocation(D->getNamespaceLoc(), Record);
678   Writer.AddSourceRange(D->getQualifierRange(), Record);
679   Writer.AddNestedNameSpecifier(D->getQualifier(), Record);
680   Writer.AddSourceLocation(D->getTargetNameLoc(), Record);
681   Writer.AddDeclRef(D->getNamespace(), Record);
682   Code = serialization::DECL_NAMESPACE_ALIAS;
683 }
684 
685 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
686   VisitNamedDecl(D);
687   Writer.AddSourceRange(D->getNestedNameRange(), Record);
688   Writer.AddSourceLocation(D->getUsingLocation(), Record);
689   Writer.AddNestedNameSpecifier(D->getTargetNestedNameDecl(), Record);
690   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
691   Writer.AddDeclRef(D->FirstUsingShadow, Record);
692   Record.push_back(D->isTypeName());
693   Writer.AddDeclRef(Context.getInstantiatedFromUsingDecl(D), Record);
694   Code = serialization::DECL_USING;
695 }
696 
697 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
698   VisitNamedDecl(D);
699   Writer.AddDeclRef(D->getTargetDecl(), Record);
700   Writer.AddDeclRef(D->UsingOrNextShadow, Record);
701   Writer.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D), Record);
702   Code = serialization::DECL_USING_SHADOW;
703 }
704 
705 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
706   VisitNamedDecl(D);
707   Writer.AddSourceLocation(D->getUsingLoc(), Record);
708   Writer.AddSourceLocation(D->getNamespaceKeyLocation(), Record);
709   Writer.AddSourceRange(D->getQualifierRange(), Record);
710   Writer.AddNestedNameSpecifier(D->getQualifier(), Record);
711   Writer.AddDeclRef(D->getNominatedNamespace(), Record);
712   Writer.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()), Record);
713   Code = serialization::DECL_USING_DIRECTIVE;
714 }
715 
716 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
717   VisitValueDecl(D);
718   Writer.AddSourceRange(D->getTargetNestedNameRange(), Record);
719   Writer.AddSourceLocation(D->getUsingLoc(), Record);
720   Writer.AddNestedNameSpecifier(D->getTargetNestedNameSpecifier(), Record);
721   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
722   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
723 }
724 
725 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
726                                                UnresolvedUsingTypenameDecl *D) {
727   VisitTypeDecl(D);
728   Writer.AddSourceRange(D->getTargetNestedNameRange(), Record);
729   Writer.AddSourceLocation(D->getUsingLoc(), Record);
730   Writer.AddSourceLocation(D->getTypenameLoc(), Record);
731   Writer.AddNestedNameSpecifier(D->getTargetNestedNameSpecifier(), Record);
732   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
733 }
734 
735 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
736   VisitRecordDecl(D);
737 
738   CXXRecordDecl *DefinitionDecl = 0;
739   if (D->DefinitionData)
740     DefinitionDecl = D->DefinitionData->Definition;
741   Writer.AddDeclRef(DefinitionDecl, Record);
742   if (D == DefinitionDecl)
743     Writer.AddCXXDefinitionData(D, Record);
744 
745   enum {
746     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
747   };
748   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
749     Record.push_back(CXXRecTemplate);
750     Writer.AddDeclRef(TemplD, Record);
751   } else if (MemberSpecializationInfo *MSInfo
752                = D->getMemberSpecializationInfo()) {
753     Record.push_back(CXXRecMemberSpecialization);
754     Writer.AddDeclRef(MSInfo->getInstantiatedFrom(), Record);
755     Record.push_back(MSInfo->getTemplateSpecializationKind());
756     Writer.AddSourceLocation(MSInfo->getPointOfInstantiation(), Record);
757   } else {
758     Record.push_back(CXXRecNotTemplate);
759   }
760 
761   // Store the key function to avoid deserializing every method so we can
762   // compute it.
763   if (D->IsDefinition)
764     Writer.AddDeclRef(Context.getKeyFunction(D), Record);
765 
766   Code = serialization::DECL_CXX_RECORD;
767 }
768 
769 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
770   VisitFunctionDecl(D);
771   Record.push_back(D->size_overridden_methods());
772   for (CXXMethodDecl::method_iterator
773          I = D->begin_overridden_methods(), E = D->end_overridden_methods();
774          I != E; ++I)
775     Writer.AddDeclRef(*I, Record);
776   Code = serialization::DECL_CXX_METHOD;
777 }
778 
779 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
780   VisitCXXMethodDecl(D);
781 
782   Record.push_back(D->IsExplicitSpecified);
783   Record.push_back(D->ImplicitlyDefined);
784   Writer.AddCXXCtorInitializers(D->CtorInitializers, D->NumCtorInitializers,
785                                 Record);
786 
787   Code = serialization::DECL_CXX_CONSTRUCTOR;
788 }
789 
790 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
791   VisitCXXMethodDecl(D);
792 
793   Record.push_back(D->ImplicitlyDefined);
794   Writer.AddDeclRef(D->OperatorDelete, Record);
795 
796   Code = serialization::DECL_CXX_DESTRUCTOR;
797 }
798 
799 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
800   VisitCXXMethodDecl(D);
801   Record.push_back(D->IsExplicitSpecified);
802   Code = serialization::DECL_CXX_CONVERSION;
803 }
804 
805 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
806   VisitDecl(D);
807   Writer.AddSourceLocation(D->getColonLoc(), Record);
808   Code = serialization::DECL_ACCESS_SPEC;
809 }
810 
811 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
812   VisitDecl(D);
813   Record.push_back(D->Friend.is<TypeSourceInfo*>());
814   if (D->Friend.is<TypeSourceInfo*>())
815     Writer.AddTypeSourceInfo(D->Friend.get<TypeSourceInfo*>(), Record);
816   else
817     Writer.AddDeclRef(D->Friend.get<NamedDecl*>(), Record);
818   Writer.AddDeclRef(D->getNextFriend(), Record);
819   Record.push_back(D->UnsupportedFriend);
820   Writer.AddSourceLocation(D->FriendLoc, Record);
821   Code = serialization::DECL_FRIEND;
822 }
823 
824 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
825   VisitDecl(D);
826   Record.push_back(D->getNumTemplateParameters());
827   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
828     Writer.AddTemplateParameterList(D->getTemplateParameterList(i), Record);
829   Record.push_back(D->getFriendDecl() != 0);
830   if (D->getFriendDecl())
831     Writer.AddDeclRef(D->getFriendDecl(), Record);
832   else
833     Writer.AddTypeSourceInfo(D->getFriendType(), Record);
834   Writer.AddSourceLocation(D->getFriendLoc(), Record);
835   Code = serialization::DECL_FRIEND_TEMPLATE;
836 }
837 
838 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
839   VisitNamedDecl(D);
840 
841   Writer.AddDeclRef(D->getTemplatedDecl(), Record);
842   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
843 }
844 
845 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
846   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
847   // getCommonPtr() can be used while this is still initializing.
848 
849   Writer.AddDeclRef(D->getPreviousDeclaration(), Record);
850   if (D->getPreviousDeclaration() == 0) {
851     // This TemplateDecl owns the CommonPtr; write it.
852     assert(D->isCanonicalDecl());
853 
854     Writer.AddDeclRef(D->getInstantiatedFromMemberTemplate(), Record);
855     if (D->getInstantiatedFromMemberTemplate())
856       Record.push_back(D->isMemberSpecialization());
857 
858     Writer.AddDeclRef(D->getCommonPtr()->Latest, Record);
859   } else {
860     RedeclarableTemplateDecl *First = D->getFirstDeclaration();
861     assert(First != D);
862     // If this is a most recent redeclaration that is pointed to by a first decl
863     // in a chained PCH, keep track of the association with the map so we can
864     // update the first decl during AST reading.
865     if (First->getMostRecentDeclaration() == D &&
866         First->getPCHLevel() > D->getPCHLevel()) {
867       assert(Writer.FirstLatestDecls.find(First)==Writer.FirstLatestDecls.end()
868              && "The latest is already set");
869       Writer.FirstLatestDecls[First] = D;
870     }
871   }
872 
873   VisitTemplateDecl(D);
874   Record.push_back(D->getIdentifierNamespace());
875 }
876 
877 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
878   VisitRedeclarableTemplateDecl(D);
879 
880   if (D->getPreviousDeclaration() == 0) {
881     typedef llvm::FoldingSet<ClassTemplateSpecializationDecl> CTSDSetTy;
882     CTSDSetTy &CTSDSet = D->getSpecializations();
883     Record.push_back(CTSDSet.size());
884     for (CTSDSetTy::iterator I=CTSDSet.begin(), E = CTSDSet.end(); I!=E; ++I) {
885       assert(I->isCanonicalDecl() && "Expected only canonical decls in set");
886       Writer.AddDeclRef(&*I, Record);
887     }
888 
889     typedef llvm::FoldingSet<ClassTemplatePartialSpecializationDecl> CTPSDSetTy;
890     CTPSDSetTy &CTPSDSet = D->getPartialSpecializations();
891     Record.push_back(CTPSDSet.size());
892     for (CTPSDSetTy::iterator I=CTPSDSet.begin(), E=CTPSDSet.end(); I!=E; ++I) {
893       assert(I->isCanonicalDecl() && "Expected only canonical decls in set");
894       Writer.AddDeclRef(&*I, Record);
895     }
896 
897     // InjectedClassNameType is computed, no need to write it.
898   }
899   Code = serialization::DECL_CLASS_TEMPLATE;
900 }
901 
902 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
903                                            ClassTemplateSpecializationDecl *D) {
904   VisitCXXRecordDecl(D);
905 
906   llvm::PointerUnion<ClassTemplateDecl *,
907                      ClassTemplatePartialSpecializationDecl *> InstFrom
908     = D->getSpecializedTemplateOrPartial();
909   Decl *InstFromD;
910   if (InstFrom.is<ClassTemplateDecl *>()) {
911     InstFromD = InstFrom.get<ClassTemplateDecl *>();
912     Writer.AddDeclRef(InstFromD, Record);
913   } else {
914     InstFromD = InstFrom.get<ClassTemplatePartialSpecializationDecl *>();
915     Writer.AddDeclRef(InstFromD, Record);
916     Writer.AddTemplateArgumentList(&D->getTemplateInstantiationArgs(), Record);
917     InstFromD = cast<ClassTemplatePartialSpecializationDecl>(InstFromD)->
918                     getSpecializedTemplate();
919   }
920 
921   // Explicit info.
922   Writer.AddTypeSourceInfo(D->getTypeAsWritten(), Record);
923   if (D->getTypeAsWritten()) {
924     Writer.AddSourceLocation(D->getExternLoc(), Record);
925     Writer.AddSourceLocation(D->getTemplateKeywordLoc(), Record);
926   }
927 
928   Writer.AddTemplateArgumentList(&D->getTemplateArgs(), Record);
929   Writer.AddSourceLocation(D->getPointOfInstantiation(), Record);
930   Record.push_back(D->getSpecializationKind());
931 
932   if (D->isCanonicalDecl()) {
933     // When reading, we'll add it to the folding set of the following template.
934     Writer.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl(), Record);
935   }
936 
937   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
938 }
939 
940 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
941                                     ClassTemplatePartialSpecializationDecl *D) {
942   VisitClassTemplateSpecializationDecl(D);
943 
944   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
945 
946   Record.push_back(D->getNumTemplateArgsAsWritten());
947   for (int i = 0, e = D->getNumTemplateArgsAsWritten(); i != e; ++i)
948     Writer.AddTemplateArgumentLoc(D->getTemplateArgsAsWritten()[i], Record);
949 
950   Record.push_back(D->getSequenceNumber());
951 
952   // These are read/set from/to the first declaration.
953   if (D->getPreviousDeclaration() == 0) {
954     Writer.AddDeclRef(D->getInstantiatedFromMember(), Record);
955     Record.push_back(D->isMemberSpecialization());
956   }
957 
958   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
959 }
960 
961 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
962   VisitRedeclarableTemplateDecl(D);
963 
964   if (D->getPreviousDeclaration() == 0) {
965     // This FunctionTemplateDecl owns the CommonPtr; write it.
966 
967     // Write the function specialization declarations.
968     Record.push_back(D->getSpecializations().size());
969     for (llvm::FoldingSet<FunctionTemplateSpecializationInfo>::iterator
970            I = D->getSpecializations().begin(),
971            E = D->getSpecializations().end()   ; I != E; ++I) {
972       assert(I->Function->isCanonicalDecl() &&
973              "Expected only canonical decls in set");
974       Writer.AddDeclRef(I->Function, Record);
975     }
976   }
977   Code = serialization::DECL_FUNCTION_TEMPLATE;
978 }
979 
980 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
981   VisitTypeDecl(D);
982 
983   Record.push_back(D->wasDeclaredWithTypename());
984   Record.push_back(D->isParameterPack());
985   Record.push_back(D->defaultArgumentWasInherited());
986   Writer.AddTypeSourceInfo(D->getDefaultArgumentInfo(), Record);
987 
988   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
989 }
990 
991 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
992   VisitVarDecl(D);
993   // TemplateParmPosition.
994   Record.push_back(D->getDepth());
995   Record.push_back(D->getPosition());
996   // Rest of NonTypeTemplateParmDecl.
997   Record.push_back(D->isParameterPack());
998   Record.push_back(D->getDefaultArgument() != 0);
999   if (D->getDefaultArgument()) {
1000     Writer.AddStmt(D->getDefaultArgument());
1001     Record.push_back(D->defaultArgumentWasInherited());
1002   }
1003   Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1004 }
1005 
1006 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1007   VisitTemplateDecl(D);
1008   // TemplateParmPosition.
1009   Record.push_back(D->getDepth());
1010   Record.push_back(D->getPosition());
1011   // Rest of TemplateTemplateParmDecl.
1012   Writer.AddTemplateArgumentLoc(D->getDefaultArgument(), Record);
1013   Record.push_back(D->defaultArgumentWasInherited());
1014   Record.push_back(D->isParameterPack());
1015   Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1016 }
1017 
1018 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1019   VisitDecl(D);
1020   Writer.AddStmt(D->getAssertExpr());
1021   Writer.AddStmt(D->getMessage());
1022   Code = serialization::DECL_STATIC_ASSERT;
1023 }
1024 
1025 /// \brief Emit the DeclContext part of a declaration context decl.
1026 ///
1027 /// \param LexicalOffset the offset at which the DECL_CONTEXT_LEXICAL
1028 /// block for this declaration context is stored. May be 0 to indicate
1029 /// that there are no declarations stored within this context.
1030 ///
1031 /// \param VisibleOffset the offset at which the DECL_CONTEXT_VISIBLE
1032 /// block for this declaration context is stored. May be 0 to indicate
1033 /// that there are no declarations visible from this context. Note
1034 /// that this value will not be emitted for non-primary declaration
1035 /// contexts.
1036 void ASTDeclWriter::VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
1037                                      uint64_t VisibleOffset) {
1038   Record.push_back(LexicalOffset);
1039   Record.push_back(VisibleOffset);
1040 }
1041 
1042 template <typename T>
1043 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1044   enum { NoRedeclaration = 0, PointsToPrevious, PointsToLatest };
1045   if (D->RedeclLink.getNext() == D) {
1046     Record.push_back(NoRedeclaration);
1047   } else {
1048     Record.push_back(D->RedeclLink.NextIsPrevious() ? PointsToPrevious
1049                                                     : PointsToLatest);
1050     Writer.AddDeclRef(D->RedeclLink.getPointer(), Record);
1051   }
1052 
1053   T *First = D->getFirstDeclaration();
1054   T *ThisDecl = static_cast<T*>(D);
1055   // If this is a most recent redeclaration that is pointed to by a first decl
1056   // in a chained PCH, keep track of the association with the map so we can
1057   // update the first decl during AST reading.
1058   if (ThisDecl != First && First->getMostRecentDeclaration() == ThisDecl &&
1059       First->getPCHLevel() > ThisDecl->getPCHLevel()) {
1060     assert(Writer.FirstLatestDecls.find(First) == Writer.FirstLatestDecls.end()
1061            && "The latest is already set");
1062     Writer.FirstLatestDecls[First] = ThisDecl;
1063   }
1064 }
1065 
1066 //===----------------------------------------------------------------------===//
1067 // ASTWriter Implementation
1068 //===----------------------------------------------------------------------===//
1069 
1070 void ASTWriter::WriteDeclsBlockAbbrevs() {
1071   using namespace llvm;
1072   // Abbreviation for DECL_PARM_VAR.
1073   BitCodeAbbrev *Abv = new BitCodeAbbrev();
1074   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
1075 
1076   // Decl
1077   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1078   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1079   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
1080   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl (!?)
1081   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1082   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1083   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1084   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1085   Abv->Add(BitCodeAbbrevOp(0));                       // PCH level
1086 
1087   // NamedDecl
1088   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1089   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1090   // ValueDecl
1091   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1092   // DeclaratorDecl
1093   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1094   Abv->Add(BitCodeAbbrevOp(serialization::PREDEF_TYPE_NULL_ID)); // InfoType
1095   // VarDecl
1096   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1097   Abv->Add(BitCodeAbbrevOp(0));                       // StorageClass
1098   Abv->Add(BitCodeAbbrevOp(0));                       // StorageClassAsWritten
1099   Abv->Add(BitCodeAbbrevOp(0));                       // isThreadSpecified
1100   Abv->Add(BitCodeAbbrevOp(0));                       // hasCXXDirectInitializer
1101   Abv->Add(BitCodeAbbrevOp(0));                       // isExceptionVariable
1102   Abv->Add(BitCodeAbbrevOp(0));                       // isNRVOVariable
1103   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
1104   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
1105   // ParmVarDecl
1106   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
1107   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
1108   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
1109 
1110   ParmVarDeclAbbrev = Stream.EmitAbbrev(Abv);
1111 
1112   Abv = new BitCodeAbbrev();
1113   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
1114   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1115   DeclContextLexicalAbbrev = Stream.EmitAbbrev(Abv);
1116 
1117   Abv = new BitCodeAbbrev();
1118   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
1119   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1120   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1121   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(Abv);
1122 }
1123 
1124 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
1125 /// consumers of the AST.
1126 ///
1127 /// Such decls will always be deserialized from the AST file, so we would like
1128 /// this to be as restrictive as possible. Currently the predicate is driven by
1129 /// code generation requirements, if other clients have a different notion of
1130 /// what is "required" then we may have to consider an alternate scheme where
1131 /// clients can iterate over the top-level decls and get information on them,
1132 /// without necessary deserializing them. We could explicitly require such
1133 /// clients to use a separate API call to "realize" the decl. This should be
1134 /// relatively painless since they would presumably only do it for top-level
1135 /// decls.
1136 static bool isRequiredDecl(const Decl *D, ASTContext &Context) {
1137   // File scoped assembly or obj-c implementation must be seen.
1138   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplementationDecl>(D))
1139     return true;
1140 
1141   return Context.DeclMustBeEmitted(D);
1142 }
1143 
1144 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
1145   // Switch case IDs are per Decl.
1146   ClearSwitchCaseIDs();
1147 
1148   RecordData Record;
1149   ASTDeclWriter W(*this, Context, Record);
1150 
1151   // If this declaration is also a DeclContext, write blocks for the
1152   // declarations that lexically stored inside its context and those
1153   // declarations that are visible from its context. These blocks
1154   // are written before the declaration itself so that we can put
1155   // their offsets into the record for the declaration.
1156   uint64_t LexicalOffset = 0;
1157   uint64_t VisibleOffset = 0;
1158   DeclContext *DC = dyn_cast<DeclContext>(D);
1159   if (DC) {
1160     LexicalOffset = WriteDeclContextLexicalBlock(Context, DC);
1161     VisibleOffset = WriteDeclContextVisibleBlock(Context, DC);
1162   }
1163 
1164   // Determine the ID for this declaration
1165   serialization::DeclID &IDR = DeclIDs[D];
1166   if (IDR == 0)
1167     IDR = NextDeclID++;
1168   serialization::DeclID ID = IDR;
1169 
1170   if (ID < FirstDeclID) {
1171     // We're replacing a decl in a previous file.
1172     ReplacedDecls.push_back(std::make_pair(ID, Stream.GetCurrentBitNo()));
1173   } else {
1174     unsigned Index = ID - FirstDeclID;
1175 
1176     // Record the offset for this declaration
1177     if (DeclOffsets.size() == Index)
1178       DeclOffsets.push_back(Stream.GetCurrentBitNo());
1179     else if (DeclOffsets.size() < Index) {
1180       DeclOffsets.resize(Index+1);
1181       DeclOffsets[Index] = Stream.GetCurrentBitNo();
1182     }
1183   }
1184 
1185   // Build and emit a record for this declaration
1186   Record.clear();
1187   W.Code = (serialization::DeclCode)0;
1188   W.AbbrevToUse = 0;
1189   W.Visit(D);
1190   if (DC) W.VisitDeclContext(DC, LexicalOffset, VisibleOffset);
1191 
1192   if (!W.Code)
1193     llvm::report_fatal_error(llvm::StringRef("unexpected declaration kind '") +
1194                             D->getDeclKindName() + "'");
1195   Stream.EmitRecord(W.Code, Record, W.AbbrevToUse);
1196 
1197   // Flush any expressions that were written as part of this declaration.
1198   FlushStmts();
1199 
1200   // Flush C++ base specifiers, if there are any.
1201   FlushCXXBaseSpecifiers();
1202 
1203   // Note "external" declarations so that we can add them to a record in the
1204   // AST file later.
1205   //
1206   // FIXME: This should be renamed, the predicate is much more complicated.
1207   if (isRequiredDecl(D, Context))
1208     ExternalDefinitions.push_back(ID);
1209 }
1210