1 files changed, 47 insertions, 16 deletions

diff --git a/clang/lib/Serialization/InMemoryModuleCache.cpp b/clang/lib/Serialization/InMemoryModuleCache.cpp
index 130ece0..d35fa2a 100644
--- a/clang/lib/Serialization/InMemoryModuleCache.cpp
+++ b/clang/lib/Serialization/InMemoryModuleCache.cpp
@@ -11,39 +11,70 @@
 
 using namespace clang;
 
+InMemoryModuleCache::State
+InMemoryModuleCache::getPCMState(llvm::StringRef Filename) const {
+  auto I = PCMs.find(Filename);
+  if (I == PCMs.end())
+    return Unknown;
+  if (I->second.IsFinal)
+    return Final;
+  return I->second.Buffer ? Tentative : ToBuild;
+}
+
 llvm::MemoryBuffer &
-InMemoryModuleCache::addBuffer(llvm::StringRef Filename,
-                               std::unique_ptr<llvm::MemoryBuffer> Buffer) {
-  auto Insertion = PCMs.insert({Filename, PCM{std::move(Buffer), NextIndex++}});
-  assert(Insertion.second && "Already has a buffer");
+InMemoryModuleCache::addPCM(llvm::StringRef Filename,
+                            std::unique_ptr<llvm::MemoryBuffer> Buffer) {
+  auto Insertion = PCMs.insert(std::make_pair(Filename, std::move(Buffer)));
+  assert(Insertion.second && "Already has a PCM");
   return *Insertion.first->second.Buffer;
 }
 
+llvm::MemoryBuffer &
+InMemoryModuleCache::addBuiltPCM(llvm::StringRef Filename,
+                                 std::unique_ptr<llvm::MemoryBuffer> Buffer) {
+  auto &PCM = PCMs[Filename];
+  assert(!PCM.IsFinal && "Trying to override finalized PCM?");
+  assert(!PCM.Buffer && "Trying to override tentative PCM?");
+  PCM.Buffer = std::move(Buffer);
+  PCM.IsFinal = true;
+  return *PCM.Buffer;
+}
+
 llvm::MemoryBuffer *
-InMemoryModuleCache::lookupBuffer(llvm::StringRef Filename) {
+InMemoryModuleCache::lookupPCM(llvm::StringRef Filename) const {
   auto I = PCMs.find(Filename);
   if (I == PCMs.end())
     return nullptr;
   return I->second.Buffer.get();
 }
 
-bool InMemoryModuleCache::isBufferFinal(llvm::StringRef Filename) {
-  auto I = PCMs.find(Filename);
-  if (I == PCMs.end())
-    return false;
-  return I->second.Index < FirstRemovableIndex;
+bool InMemoryModuleCache::isPCMFinal(llvm::StringRef Filename) const {
+  return getPCMState(Filename) == Final;
+}
+
+bool InMemoryModuleCache::shouldBuildPCM(llvm::StringRef Filename) const {
+  return getPCMState(Filename) == ToBuild;
 }
 
-bool InMemoryModuleCache::tryToRemoveBuffer(llvm::StringRef Filename) {
+bool InMemoryModuleCache::tryToDropPCM(llvm::StringRef Filename) {
   auto I = PCMs.find(Filename);
-  assert(I != PCMs.end() && "No buffer to remove...");
-  if (I->second.Index < FirstRemovableIndex)
+  assert(I != PCMs.end() && "PCM to remove is unknown...");
+
+  auto &PCM = I->second;
+  assert(PCM.Buffer && "PCM to remove is scheduled to be built...");
+
+  if (PCM.IsFinal)
     return true;
 
-  PCMs.erase(I);
+  PCM.Buffer.reset();
   return false;
 }
 
-void InMemoryModuleCache::finalizeCurrentBuffers() {
-  FirstRemovableIndex = NextIndex;
+void InMemoryModuleCache::finalizePCM(llvm::StringRef Filename) {
+  auto I = PCMs.find(Filename);
+  assert(I != PCMs.end() && "PCM to finalize is unknown...");
+
+  auto &PCM = I->second;
+  assert(PCM.Buffer && "Trying to finalize a dropped PCM...");
+  PCM.IsFinal = true;
 }