Switch case IDs conflict between chained PCHs; since there is no need to be global, make them local to a decl.

llvm-svn: 117540

clang/include/clang/Serialization/ASTReader.h

@@ -1162,6 +1162,8 @@ public:
   /// deserialized and has the given ID.
   void RecordLabelStmt(LabelStmt *S, unsigned ID);
 
+  void ClearSwitchCaseIDs();
+
   /// \brief Set the label of the given statement to the label
   /// identified by ID.
   ///

clang/include/clang/Serialization/ASTWriter.h

@@ -484,6 +484,8 @@ public:
   /// \brief Retrieve the ID for the given switch-case statement.
   unsigned getSwitchCaseID(SwitchCase *S);
 
+  void ClearSwitchCaseIDs();
+
   /// \brief Retrieve the ID for the given label statement, which may
   /// or may not have been emitted yet.
   unsigned GetLabelID(LabelStmt *S);

clang/lib/Serialization/ASTReader.cpp

@@ -3284,6 +3284,9 @@ Decl *ASTReader::GetDecl(DeclID ID) {
 /// source each time it is called, and is meant to be used via a
 /// LazyOffsetPtr (which is used by Decls for the body of functions, etc).
 Stmt *ASTReader::GetExternalDeclStmt(uint64_t Offset) {
+  // Switch case IDs are per Decl.
+  ClearSwitchCaseIDs();
+
   // Offset here is a global offset across the entire chain.
   for (unsigned I = 0, N = Chain.size(); I != N; ++I) {
     PerFileData &F = *Chain[N - I - 1];
@@ -4252,6 +4255,10 @@ SwitchCase *ASTReader::getSwitchCaseWithID(unsigned ID) {
   return SwitchCaseStmts[ID];
 }
 
+void ASTReader::ClearSwitchCaseIDs() {
+  SwitchCaseStmts.clear();
+}
+
 /// \brief Record that the given label statement has been
 /// deserialized and has the given ID.
 void ASTReader::RecordLabelStmt(LabelStmt *S, unsigned ID) {

clang/lib/Serialization/ASTWriterDecl.cpp

@@ -1128,6 +1128,9 @@ static bool isRequiredDecl(const Decl *D, ASTContext &Context) {
 }
 
 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
+  // Switch case IDs are per Decl.
+  ClearSwitchCaseIDs();
+
   RecordData Record;
   ASTDeclWriter W(*this, Context, Record);
 

clang/lib/Serialization/ASTWriterStmt.cpp

@@ -1311,6 +1311,10 @@ unsigned ASTWriter::getSwitchCaseID(SwitchCase *S) {
   return SwitchCaseIDs[S];
 }
 
+void ASTWriter::ClearSwitchCaseIDs() {
+  SwitchCaseIDs.clear();
+}
+
 /// \brief Retrieve the ID for the given label statement, which may
 /// or may not have been emitted yet.
 unsigned ASTWriter::GetLabelID(LabelStmt *S) {