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, 7 insertions, 4 deletions

diff --git a/clang/lib/Serialization/ModuleManager.cpp b/clang/lib/Serialization/ModuleManager.cpp
index 9b326d2..2656220 100644
--- a/clang/lib/Serialization/ModuleManager.cpp
+++ b/clang/lib/Serialization/ModuleManager.cpp
@@ -163,7 +163,7 @@ ModuleManager::addModule(StringRef FileName, ModuleKind Type,
   // Load the contents of the module
   if (std::unique_ptr<llvm::MemoryBuffer> Buffer = lookupBuffer(FileName)) {
     // The buffer was already provided for us.
-    NewModule->Buffer = &ModuleCache->addFinalPCM(FileName, std::move(Buffer));
+    NewModule->Buffer = &ModuleCache->addBuiltPCM(FileName, std::move(Buffer));
     // Since the cached buffer is reused, it is safe to close the file
     // descriptor that was opened while stat()ing the PCM in
     // lookupModuleFile() above, it won't be needed any longer.
@@ -173,6 +173,11 @@ ModuleManager::addModule(StringRef FileName, ModuleKind Type,
     NewModule->Buffer = Buffer;
     // As above, the file descriptor is no longer needed.
     Entry->closeFile();
+  } else if (getModuleCache().shouldBuildPCM(FileName)) {
+    // Report that the module is out of date, since we tried (and failed) to
+    // import it earlier.
+    Entry->closeFile();
+    return OutOfDate;
   } else {
     // Open the AST file.
     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Buf((std::error_code()));
@@ -180,9 +185,7 @@ ModuleManager::addModule(StringRef FileName, ModuleKind Type,
       Buf = llvm::MemoryBuffer::getSTDIN();
     } else {
       // Get a buffer of the file and close the file descriptor when done.
-      // The file is volatile because in a parallel build we expect multiple
-      // compiler processes to use the same module file rebuilding it if needed.
-      Buf = FileMgr.getBufferForFile(NewModule->File, /*isVolatile=*/true);
+      Buf = FileMgr.getBufferForFile(NewModule->File, /*isVolatile=*/false);
     }
 
     if (!Buf) {