Re-implement (de-)serialization of redeclaration chains for

redeclaration templates (RedeclarableTemplateDecl), similarly to the
way (de-)serialization is implemented for Redeclarable<T>. In the
process, found a simpler formulation for handling redeclaration
chains and implemented that in both places.

The new test establishes that we're building the redeclaration chains
properly. However, the FIXME indicates where we're tickling a
different bug that has to do with us not setting the DefinitionData
pointer properly in redeclarations that we detected after the
definition itself was deserialized. The (separable) fix for that bug
is forthcoming.

llvm-svn: 146883

1 files changed, 39 insertions, 41 deletions

diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index bb4359a..cb1c6f0 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -188,7 +188,7 @@ void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
   if (!D->hasAttrs() &&
       !D->isImplicit() &&
       !D->isUsed(false) &&
-      D->RedeclLink.getPointer() == D &&
+      !D->getPreviousDeclaration() &&
       !D->isInvalidDecl() &&
       !D->isReferenced() &&
       !D->isTopLevelDeclInObjCContainer() &&
@@ -238,7 +238,7 @@ void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
       !D->isImplicit() &&
       !D->isUsed(false) &&
       !D->hasExtInfo() &&
-      D->RedeclLink.getPointer() == D &&
+      !D->getPreviousDeclaration() &&
       !D->isInvalidDecl() &&
       !D->isReferenced() &&
       !D->isTopLevelDeclInObjCContainer() &&
@@ -262,7 +262,7 @@ void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
       !D->isImplicit() &&
       !D->isUsed(false) &&
       !D->hasExtInfo() &&
-      D->RedeclLink.getPointer() == D &&
+      !D->getPreviousDeclaration() &&
       !D->isInvalidDecl() &&
       !D->isReferenced() &&
       !D->isTopLevelDeclInObjCContainer() &&
@@ -708,7 +708,7 @@ void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
       !D->isModulePrivate() &&
       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
       !D->hasExtInfo() &&
-      D->RedeclLink.getPointer() == D &&
+      !D->getPreviousDeclaration() &&
       !D->hasCXXDirectInitializer() &&
       D->getInit() == 0 &&
       !isa<ParmVarDecl>(D) &&
@@ -1051,32 +1051,34 @@ void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
   // getCommonPtr() can be used while this is still initializing.
-
-  Writer.AddDeclRef(D->getPreviousDeclaration(), Record);
-  if (D->getPreviousDeclaration())
-    Writer.AddDeclRef(D->getFirstDeclaration(), Record);
-
-  if (D->getPreviousDeclaration() == 0) {
-    // This TemplateDecl owns the CommonPtr; write it.
-    assert(D->isCanonicalDecl());
-
+  enum { FirstDeclaration, PointsToPrevious };
+  RedeclarableTemplateDecl *Prev = D->getPreviousDeclaration();
+  RedeclarableTemplateDecl *First = 0;
+  if (!Prev) {
+    Record.push_back(FirstDeclaration);
+    
+    // This declaration owns the 'common' pointer, so serialize that data now.
     Writer.AddDeclRef(D->getInstantiatedFromMemberTemplate(), Record);
     if (D->getInstantiatedFromMemberTemplate())
       Record.push_back(D->isMemberSpecialization());
-
-    Writer.AddDeclRef(D->getCommonPtr()->Latest, Record);
   } else {
-    RedeclarableTemplateDecl *First = D->getFirstDeclaration();
-    assert(First != D);
-    // If this is a most recent redeclaration that is pointed to by a first decl
-    // in a chained PCH, keep track of the association with the map so we can
-    // update the first decl during AST reading.
-    if (First->getMostRecentDeclaration() == D &&
-        First->isFromASTFile() && !D->isFromASTFile()) {
-      assert(Writer.FirstLatestDecls.find(First)==Writer.FirstLatestDecls.end()
-             && "The latest is already set");
-      Writer.FirstLatestDecls[First] = D;
-    }
+    First = D->getFirstDeclaration();
+    Record.push_back(PointsToPrevious);
+    Writer.AddDeclRef(First, Record);
+    Writer.AddDeclRef(Prev, Record);    
+  }
+  
+  if (D->getMostRecentDeclaration() != D && (!Prev || Prev->isFromASTFile())) {
+    if (!First)
+      First = D->getFirstDeclaration();
+    
+    // Capture the set of redeclarations in this file.
+    LocalRedeclarationsInfo LocalInfo = {
+      Writer.GetDeclRef(First),
+      Writer.GetDeclRef(D),
+      Writer.GetDeclRef(D->getMostRecentDeclaration())
+    };
+    Writer.LocalRedeclarations.push_back(LocalInfo);
   }
 
   VisitTemplateDecl(D);
@@ -1274,19 +1276,19 @@ void ASTDeclWriter::VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
 
 template <typename T>
 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
-  enum { OnlyDeclaration = 0, FirstInFile, PointsToPrevious };
-  if (D->RedeclLink.getPointer() == D) {
-    // This is the only declaration.
-    Record.push_back(OnlyDeclaration);
-    return;
-  }
-  
+  enum { FirstDeclaration = 0, PointsToPrevious };
+  T *Prev = D->getPreviousDeclaration();
   T *First = D->getFirstDeclaration();
-  if (!D->getPreviousDeclaration() ||
-      D->getPreviousDeclaration()->isFromASTFile()) {
-    Record.push_back(FirstInFile);
+  
+  if (!Prev) {
+    Record.push_back(FirstDeclaration);
+  } else {  
+    Record.push_back(PointsToPrevious);
     Writer.AddDeclRef(First, Record);
-
+    Writer.AddDeclRef(D->getPreviousDeclaration(), Record);
+  }
+  
+  if (D->RedeclLink.getPointer() != D && (!Prev || Prev->isFromASTFile())) {
     // Capture the set of redeclarations in this file.
     LocalRedeclarationsInfo LocalInfo = {
       Writer.GetDeclRef(First),
@@ -1294,10 +1296,6 @@ void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
       Writer.GetDeclRef(D->getMostRecentDeclaration())
     };
     Writer.LocalRedeclarations.push_back(LocalInfo);    
-  } else {
-    Record.push_back(PointsToPrevious);
-    Writer.AddDeclRef(First, Record);
-    Writer.AddDeclRef(D->getPreviousDeclaration(), Record);
   }
 }