[clang] Use InMemoryModuleCache for readASTFileControlBlock NFC

When a pcm has already been loaded from disk, reuse it from the
InMemoryModuleCache in readASTFileControlBlock. This avoids potentially
reading it again.

As noted in the FIXME, ideally we would also add the module to the cache
if it will be used again later, but that could modify its build state
and we do not have enough context currenlty to know if it's correct.

Differential Revision: https://reviews.llvm.org/D138160

3 files changed, 11 insertions, 7 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 6402f16..79bbf37 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -252,7 +252,8 @@ static void collectIncludePCH(CompilerInstance &CI,
     // used here since we're not interested in validating the PCH at this time,
     // but only to check whether this is a file containing an AST.
     if (!ASTReader::readASTFileControlBlock(
-            Dir->path(), FileMgr, CI.getPCHContainerReader(),
+            Dir->path(), FileMgr, CI.getModuleCache(),
+            CI.getPCHContainerReader(),
             /*FindModuleFileExtensions=*/false, Validator,
             /*ValidateDiagnosticOptions=*/false))
       MDC->addFile(Dir->path());
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 76ef0cb..8fa96be2 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -778,8 +778,9 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
            Dir != DirEnd && !EC; Dir.increment(EC)) {
         // Check whether this is an acceptable AST file.
         if (ASTReader::isAcceptableASTFile(
-                Dir->path(), FileMgr, CI.getPCHContainerReader(),
-                CI.getLangOpts(), CI.getTargetOpts(), CI.getPreprocessorOpts(),
+                Dir->path(), FileMgr, CI.getModuleCache(),
+                CI.getPCHContainerReader(), CI.getLangOpts(),
+                CI.getTargetOpts(), CI.getPreprocessorOpts(),
                 SpecificModuleCachePath, /*RequireStrictOptionMatches=*/true)) {
           PPOpts.ImplicitPCHInclude = std::string(Dir->path());
           Found = true;
diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index b4ec389..dfb7267 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -851,7 +851,8 @@ void DumpModuleInfoAction::ExecuteAction() {
   assert(isCurrentFileAST() && "dumping non-AST?");
   // Set up the output file.
   std::unique_ptr<llvm::raw_fd_ostream> OutFile;
-  StringRef OutputFileName = getCompilerInstance().getFrontendOpts().OutputFile;
+  CompilerInstance &CI = getCompilerInstance();
+  StringRef OutputFileName = CI.getFrontendOpts().OutputFile;
   if (!OutputFileName.empty() && OutputFileName != "-") {
     std::error_code EC;
     OutFile.reset(new llvm::raw_fd_ostream(OutputFileName.str(), EC,
@@ -861,14 +862,14 @@ void DumpModuleInfoAction::ExecuteAction() {
   llvm::raw_ostream &Out = OutputStream ? *OutputStream : llvm::outs();
 
   Out << "Information for module file '" << getCurrentFile() << "':\n";
-  auto &FileMgr = getCompilerInstance().getFileManager();
+  auto &FileMgr = CI.getFileManager();
   auto Buffer = FileMgr.getBufferForFile(getCurrentFile());
   StringRef Magic = (*Buffer)->getMemBufferRef().getBuffer();
   bool IsRaw = (Magic.size() >= 4 && Magic[0] == 'C' && Magic[1] == 'P' &&
                 Magic[2] == 'C' && Magic[3] == 'H');
   Out << "  Module format: " << (IsRaw ? "raw" : "obj") << "\n";
 
-  Preprocessor &PP = getCompilerInstance().getPreprocessor();
+  Preprocessor &PP = CI.getPreprocessor();
   DumpModuleInfoListener Listener(Out);
   HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
 
@@ -966,7 +967,8 @@ void DumpModuleInfoAction::ExecuteAction() {
   // The reminder of the output is produced from the listener as the AST
   // FileCcontrolBlock is (re-)parsed.
   ASTReader::readASTFileControlBlock(
-      getCurrentFile(), FileMgr, getCompilerInstance().getPCHContainerReader(),
+      getCurrentFile(), FileMgr, CI.getModuleCache(),
+      CI.getPCHContainerReader(),
       /*FindModuleFileExtensions=*/true, Listener,
       HSOpts.ModulesValidateDiagnosticOptions);
 }