[libclang] Don't crash when saving a PCH from a prefix header

that does not exist.

rdar://11607033

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158193 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 13 insertions, 4 deletions

diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index d6bdae4aaf..1ef5ba864e 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -1133,7 +1133,8 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
                                StoredDiagnostics);
   }
 
-  Act->Execute();
+  if (!Act->Execute())
+    goto error;
 
   transferASTDataFromCompilerInstance(*Clang);
   
@@ -1795,7 +1796,13 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
                                            AST->getCurrentTopLevelHashValue()));
     Clang->setASTConsumer(new MultiplexConsumer(Consumers));
   }
-  Act->Execute();
+  if (!Act->Execute()) {
+    AST->transferASTDataFromCompilerInstance(*Clang);
+    if (OwnAST && ErrAST)
+      ErrAST->swap(OwnAST);
+
+    return 0;
+  }
 
   // Steal the created target, context, and preprocessor.
   AST->transferASTDataFromCompilerInstance(*Clang);
diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index 1ff32921d9..fb53c71fa9 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -315,7 +315,7 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
   return false;
 }
 
-void FrontendAction::Execute() {
+bool FrontendAction::Execute() {
   CompilerInstance &CI = getCompilerInstance();
 
   // Initialize the main file entry. This needs to be delayed until after PCH
@@ -325,7 +325,7 @@ void FrontendAction::Execute() {
                                     getCurrentInput().IsSystem
                                       ? SrcMgr::C_System
                                       : SrcMgr::C_User))
-      return;
+      return false;
   }
 
   if (CI.hasFrontendTimer()) {
@@ -333,6 +333,8 @@ void FrontendAction::Execute() {
     ExecuteAction();
   }
   else ExecuteAction();
+
+  return true;
 }
 
 void FrontendAction::EndSourceFile() {