commit 70d759b4eb958505a6893f2a64a0c1f613c95c2e
author Duncan P. N. Exon Smith <dexonsmith@apple.com> Tue Mar 12 18:38:04 2019 +0000
committer Duncan P. N. Exon Smith <dexonsmith@apple.com> Tue Mar 12 18:38:04 2019 +0000
tree 832d1e83afc38045e014cc317839ad3466fc9710
parent 4ab0a9f0a4e7daff3fc54fd48d429c6c2017a458

Modules: Add LangOptions::CacheGeneratedPCH

Add an option to cache the generated PCH in the ModuleCache when
emitting it.  This protects clients that build PCHs and read them in the
same process, allowing them to avoid race conditions between parallel
jobs the same way that Clang's implicit module build system does.

rdar://problem/48740787

llvm-svn: 355950

clang/lib/Serialization/ASTWriter.cpp

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 85bc281..933cc6b 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -4596,7 +4596,8 @@
 ASTFileSignature ASTWriter::WriteAST(Sema &SemaRef,
                                      const std::string &OutputFile,
                                      Module *WritingModule, StringRef isysroot,
-                                     bool hasErrors) {
+                                     bool hasErrors,
+                                     bool ShouldCacheASTInMemory) {
   WritingAST = true;
 
   ASTHasCompilerErrors = hasErrors;
@@ -4620,7 +4621,7 @@
   this->BaseDirectory.clear();
 
   WritingAST = false;
-  if (SemaRef.Context.getLangOpts().ImplicitModules && WritingModule) {
+  if (ShouldCacheASTInMemory) {
     // Construct MemoryBuffer and update buffer manager.
     ModuleCache.addBuiltPCM(OutputFile,
                             llvm::MemoryBuffer::getMemBufferCopy(

clang/lib/Serialization/GeneratePCH.cpp

diff --git a/clang/lib/Serialization/GeneratePCH.cpp b/clang/lib/Serialization/GeneratePCH.cpp
index 7c2ef5a..6d98524 100644
--- a/clang/lib/Serialization/GeneratePCH.cpp
+++ b/clang/lib/Serialization/GeneratePCH.cpp
@@ -24,12 +24,14 @@
     const Preprocessor &PP, InMemoryModuleCache &ModuleCache,
     StringRef OutputFile, StringRef isysroot, std::shared_ptr<PCHBuffer> Buffer,
     ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
-    bool AllowASTWithErrors, bool IncludeTimestamps)
+    bool AllowASTWithErrors, bool IncludeTimestamps,
+    bool ShouldCacheASTInMemory)
     : PP(PP), OutputFile(OutputFile), isysroot(isysroot.str()),
       SemaPtr(nullptr), Buffer(std::move(Buffer)), Stream(this->Buffer->Data),
       Writer(Stream, this->Buffer->Data, ModuleCache, Extensions,
              IncludeTimestamps),
-      AllowASTWithErrors(AllowASTWithErrors) {
+      AllowASTWithErrors(AllowASTWithErrors),
+      ShouldCacheASTInMemory(ShouldCacheASTInMemory) {
   this->Buffer->IsComplete = false;
 }
 
@@ -61,7 +63,8 @@
       Writer.WriteAST(*SemaPtr, OutputFile, Module, isysroot,
                       // For serialization we are lenient if the errors were
                       // only warn-as-error kind.
-                      PP.getDiagnostics().hasUncompilableErrorOccurred());
+                      PP.getDiagnostics().hasUncompilableErrorOccurred(),
+                      ShouldCacheASTInMemory);
 
   Buffer->IsComplete = true;
 }