[PCH] Mark a PCH file with a flag to indicate if the serialized AST had

compiler errors or not.

-Control whether ASTReader should reject such a PCH by a boolean flag at ASTReader's creation time.
By default, such a PCH file will be rejected with an error when trying to load it.

[libclang] Allow clang_saveTranslationUnit to create a PCH file even if compiler errors
occurred.
-Have libclang API calls accept a PCH that had compiler errors.

The general idea is that we want libclang to stay functional even if a PCH had a compiler error.
rdar://10976363.

llvm-svn: 152192

clang/lib/Frontend/CompilerInstance.cpp

@@ -306,12 +306,14 @@ void CompilerInstance::createASTContext() {
 void CompilerInstance::createPCHExternalASTSource(StringRef Path,
                                                   bool DisablePCHValidation,
                                                   bool DisableStatCache,
+                                                bool AllowPCHWithCompilerErrors,
                                                  void *DeserializationListener){
   OwningPtr<ExternalASTSource> Source;
   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
   Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
                                           DisablePCHValidation,
                                           DisableStatCache,
+                                          AllowPCHWithCompilerErrors,
                                           getPreprocessor(), getASTContext(),
                                           DeserializationListener,
                                           Preamble));
@@ -324,6 +326,7 @@ CompilerInstance::createPCHExternalASTSource(StringRef Path,
                                              const std::string &Sysroot,
                                              bool DisablePCHValidation,
                                              bool DisableStatCache,
+                                             bool AllowPCHWithCompilerErrors,
                                              Preprocessor &PP,
                                              ASTContext &Context,
                                              void *DeserializationListener,
@@ -331,7 +334,8 @@ CompilerInstance::createPCHExternalASTSource(StringRef Path,
   OwningPtr<ASTReader> Reader;
   Reader.reset(new ASTReader(PP, Context,
                              Sysroot.empty() ? "" : Sysroot.c_str(),
-                             DisablePCHValidation, DisableStatCache));
+                             DisablePCHValidation, DisableStatCache,
+                             AllowPCHWithCompilerErrors));
 
   Reader->setDeserializationListener(
             static_cast<ASTDeserializationListener *>(DeserializationListener));