Eliminate a hang while loading a sequence of redeclarable entities. In

essence, the redeclaration chain for a class could end up in an
inconsistent state while deserializing multiple declarations in that
chain, where the circular linked list was not, in fact,
circular. Since only two redeclarations of the same entity will get
loaded when we're in this state, restore circularity when both have
been loaded. Fixes <rdar://problem/10324940> / PR11195.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143037 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 9 deletions

diff --git a/lib/Serialization/ASTWriterDecl.cpp b/lib/Serialization/ASTWriterDecl.cpp
index 2925f49292..f613867926 100644
--- a/lib/Serialization/ASTWriterDecl.cpp
+++ b/lib/Serialization/ASTWriterDecl.cpp
@@ -198,8 +198,8 @@ void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
 }
 
 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
-  VisitTypeDecl(D);
   VisitRedeclarable(D);
+  VisitTypeDecl(D);
   Record.push_back(D->getIdentifierNamespace());
   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
   Record.push_back(D->isCompleteDefinition());
@@ -289,8 +289,8 @@ void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
 }
 
 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
-  VisitDeclaratorDecl(D);
   VisitRedeclarable(D);
+  VisitDeclaratorDecl(D);
 
   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
   Record.push_back(D->getIdentifierNamespace());
@@ -651,8 +651,8 @@ void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
 }
 
 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
-  VisitDeclaratorDecl(D);
   VisitRedeclarable(D);
+  VisitDeclaratorDecl(D);
   Record.push_back(D->getStorageClass()); // FIXME: stable encoding
   Record.push_back(D->getStorageClassAsWritten());
   Record.push_back(D->isThreadSpecified());
@@ -1336,6 +1336,8 @@ void ASTWriter::WriteDeclsBlockAbbrevs() {
   // Abbreviation for DECL_ENUM
   Abv = new BitCodeAbbrev();
   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
+  // Redeclarable
+  Abv->Add(BitCodeAbbrevOp(0));                         // No redeclaration
   // Decl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
@@ -1353,8 +1355,6 @@ void ASTWriter::WriteDeclsBlockAbbrevs() {
   // TypeDecl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
-  // Redeclarable
-  Abv->Add(BitCodeAbbrevOp(0));                         // No redeclaration
   // TagDecl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
@@ -1382,6 +1382,8 @@ void ASTWriter::WriteDeclsBlockAbbrevs() {
   // Abbreviation for DECL_RECORD
   Abv = new BitCodeAbbrev();
   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
+  // Redeclarable
+  Abv->Add(BitCodeAbbrevOp(0));                         // No redeclaration
   // Decl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
@@ -1399,8 +1401,6 @@ void ASTWriter::WriteDeclsBlockAbbrevs() {
   // TypeDecl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
-  // Redeclarable
-  Abv->Add(BitCodeAbbrevOp(0));                         // No redeclaration
   // TagDecl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
@@ -1422,6 +1422,8 @@ void ASTWriter::WriteDeclsBlockAbbrevs() {
   // Abbreviation for DECL_PARM_VAR
   Abv = new BitCodeAbbrev();
   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
+  // Redeclarable
+  Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
   // Decl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
@@ -1442,7 +1444,6 @@ void ASTWriter::WriteDeclsBlockAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
   // VarDecl
-  Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
   Abv->Add(BitCodeAbbrevOp(0));                       // StorageClass
   Abv->Add(BitCodeAbbrevOp(0));                       // StorageClassAsWritten
   Abv->Add(BitCodeAbbrevOp(0));                       // isThreadSpecified
@@ -1495,6 +1496,8 @@ void ASTWriter::WriteDeclsBlockAbbrevs() {
   // Abbreviation for DECL_VAR
   Abv = new BitCodeAbbrev();
   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
+  // Redeclarable
+  Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
   // Decl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
@@ -1515,7 +1518,6 @@ void ASTWriter::WriteDeclsBlockAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
   // VarDecl
-  Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // StorageClass
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // StorageClassAsWritten
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isThreadSpecified