Revert "[modules] Do not cache invalid state for modules that we attempted to load."

As per comment on https://reviews.llvm.org/D72860, it is suggested to
revert this change in the meantime, since it has introduced regression.

This reverts commit 83f4c3af021cd5322ea10fd1c4e839874c1dae49.

1 files changed, 21 insertions, 8 deletions

diff --git a/clang/lib/Serialization/InMemoryModuleCache.cpp b/clang/lib/Serialization/InMemoryModuleCache.cpp
index 68d9411..d35fa2a 100644
--- a/clang/lib/Serialization/InMemoryModuleCache.cpp
+++ b/clang/lib/Serialization/InMemoryModuleCache.cpp
@@ -11,6 +11,16 @@
 
 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::addPCM(llvm::StringRef Filename,
                             std::unique_ptr<llvm::MemoryBuffer> Buffer) {
@@ -20,11 +30,11 @@ InMemoryModuleCache::addPCM(llvm::StringRef Filename,
 }
 
 llvm::MemoryBuffer &
-InMemoryModuleCache::addFinalPCM(llvm::StringRef Filename,
+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 && "Already has a non-final PCM");
+  assert(!PCM.Buffer && "Trying to override tentative PCM?");
   PCM.Buffer = std::move(Buffer);
   PCM.IsFinal = true;
   return *PCM.Buffer;
@@ -39,21 +49,24 @@ InMemoryModuleCache::lookupPCM(llvm::StringRef Filename) const {
 }
 
 bool InMemoryModuleCache::isPCMFinal(llvm::StringRef Filename) const {
-  auto I = PCMs.find(Filename);
-  if (I == PCMs.end())
-    return false;
-  return I->second.IsFinal;
+  return getPCMState(Filename) == Final;
+}
+
+bool InMemoryModuleCache::shouldBuildPCM(llvm::StringRef Filename) const {
+  return getPCMState(Filename) == ToBuild;
 }
 
-bool InMemoryModuleCache::tryToRemovePCM(llvm::StringRef Filename) {
+bool InMemoryModuleCache::tryToDropPCM(llvm::StringRef Filename) {
   auto I = PCMs.find(Filename);
   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;
 }