Avoid writing a VTABLE_USES record in PCH if there are no entries.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110122 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 16 insertions, 12 deletions

diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index d5cf75ce3b..b415f8dea5 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -3133,13 +3133,15 @@ void PCHReader::InitializeSema(Sema &S) {
 
   // If there were any VTable uses, deserialize the information and add it
   // to Sema's vector and map of VTable uses.
-  unsigned Idx = 0;
-  for (unsigned I = 0, N = VTableUses[Idx++]; I != N; ++I) {
-    CXXRecordDecl *Class = cast<CXXRecordDecl>(GetDecl(VTableUses[Idx++]));
-    SourceLocation Loc = ReadSourceLocation(VTableUses, Idx);
-    bool DefinitionRequired = VTableUses[Idx++];
-    SemaObj->VTableUses.push_back(std::make_pair(Class, Loc));
-    SemaObj->VTablesUsed[Class] = DefinitionRequired;
+  if (!VTableUses.empty()) {
+    unsigned Idx = 0;
+    for (unsigned I = 0, N = VTableUses[Idx++]; I != N; ++I) {
+      CXXRecordDecl *Class = cast<CXXRecordDecl>(GetDecl(VTableUses[Idx++]));
+      SourceLocation Loc = ReadSourceLocation(VTableUses, Idx);
+      bool DefinitionRequired = VTableUses[Idx++];
+      SemaObj->VTableUses.push_back(std::make_pair(Class, Loc));
+      SemaObj->VTablesUsed[Class] = DefinitionRequired;
+    }
   }
 
   // If there were any dynamic classes declarations, deserialize them
diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index 971f5e8fb2..75592a41c8 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -2196,11 +2196,13 @@ void PCHWriter::WritePCHCore(Sema &SemaRef, MemorizeStatCalls *StatCalls,
 
   // Build a record containing all of the VTable uses information.
   RecordData VTableUses;
-  VTableUses.push_back(SemaRef.VTableUses.size());
-  for (unsigned I = 0, N = SemaRef.VTableUses.size(); I != N; ++I) {
-    AddDeclRef(SemaRef.VTableUses[I].first, VTableUses);
-    AddSourceLocation(SemaRef.VTableUses[I].second, VTableUses);
-    VTableUses.push_back(SemaRef.VTablesUsed[SemaRef.VTableUses[I].first]);
+  if (!SemaRef.VTableUses.empty()) {
+    VTableUses.push_back(SemaRef.VTableUses.size());
+    for (unsigned I = 0, N = SemaRef.VTableUses.size(); I != N; ++I) {
+      AddDeclRef(SemaRef.VTableUses[I].first, VTableUses);
+      AddSourceLocation(SemaRef.VTableUses[I].second, VTableUses);
+      VTableUses.push_back(SemaRef.VTablesUsed[SemaRef.VTableUses[I].first]);
+    }
   }
 
   // Build a record containing all of dynamic classes declarations.