Revert "Modules: Cache PCMs in memory and avoid a use-after-free"

This reverts commit r298165, as it broke the ARM builds.

llvm-svn: 298185

1 files changed, 6 insertions, 17 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index f660429e49d..bf15460824f 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -13,7 +13,6 @@
 #include "clang/AST/Decl.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/FileManager.h"
-#include "clang/Basic/MemoryBufferCache.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/Version.h"
@@ -56,15 +55,9 @@ using namespace clang;
 
 CompilerInstance::CompilerInstance(
     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
-    MemoryBufferCache *SharedPCMCache)
-    : ModuleLoader(/* BuildingModule = */ SharedPCMCache),
-      Invocation(new CompilerInvocation()),
-      PCMCache(SharedPCMCache ? SharedPCMCache : new MemoryBufferCache),
-      ThePCHContainerOperations(std::move(PCHContainerOps)) {
-  // Don't allow this to invalidate buffers in use by others.
-  if (SharedPCMCache)
-    getPCMCache().finalizeCurrentBuffers();
-}
+    bool BuildingModule)
+    : ModuleLoader(BuildingModule), Invocation(new CompilerInvocation()),
+      ThePCHContainerOperations(std::move(PCHContainerOps)) {}
 
 CompilerInstance::~CompilerInstance() {
   assert(OutputFiles.empty() && "Still output files in flight?");
@@ -135,8 +128,6 @@ IntrusiveRefCntPtr<ASTReader> CompilerInstance::getModuleManager() const {
   return ModuleManager;
 }
 void CompilerInstance::setModuleManager(IntrusiveRefCntPtr<ASTReader> Reader) {
-  assert(PCMCache.get() == &Reader->getModuleManager().getPCMCache() &&
-         "Expected ASTReader to use the same PCM cache");
   ModuleManager = std::move(Reader);
 }
 
@@ -379,7 +370,7 @@ void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
                        getDiagnostics(), getLangOpts(), &getTarget());
   PP = std::make_shared<Preprocessor>(
       Invocation->getPreprocessorOptsPtr(), getDiagnostics(), getLangOpts(),
-      getSourceManager(), getPCMCache(), *HeaderInfo, *this, PTHMgr,
+      getSourceManager(), *HeaderInfo, *this, PTHMgr,
       /*OwnsHeaderSearch=*/true, TUKind);
   PP->Initialize(getTarget(), getAuxTarget());
 
@@ -1082,11 +1073,9 @@ static bool compileModuleImpl(CompilerInstance &ImportingInstance,
          Invocation->getModuleHash() && "Module hash mismatch!");
   
   // Construct a compiler instance that will be used to actually create the
-  // module.  Since we're sharing a PCMCache,
-  // CompilerInstance::CompilerInstance is responsible for finalizing the
-  // buffers to prevent use-after-frees.
+  // module.
   CompilerInstance Instance(ImportingInstance.getPCHContainerOperations(),
-                            &ImportingInstance.getPreprocessor().getPCMCache());
+                            /*BuildingModule=*/true);
   auto &Inv = *Invocation;
   Instance.setInvocation(std::move(Invocation));