[clang][modules] Partially revert 48d0eb518 to fix -gmodules output

clang/include/clang/CodeGen/BackendUtil.h

@@ -39,8 +39,8 @@ enum BackendAction {
   Backend_EmitObj       ///< Emit native object files
 };
 
-void emitBackendOutput(CompilerInstance &CI, StringRef TDesc, llvm::Module *M,
-                       BackendAction Action,
+void emitBackendOutput(CompilerInstance &CI, CodeGenOptions &CGOpts,
+                       StringRef TDesc, llvm::Module *M, BackendAction Action,
                        llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
                        std::unique_ptr<raw_pwrite_stream> OS,
                        BackendConsumer *BC = nullptr);

clang/lib/CodeGen/BackendUtil.cpp

@@ -206,9 +206,10 @@ class EmitAssemblyHelper {
   }
 
 public:
-  EmitAssemblyHelper(CompilerInstance &CI, llvm::Module *M,
+  EmitAssemblyHelper(CompilerInstance &CI, CodeGenOptions &CGOpts,
+                     llvm::Module *M,
                      IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS)
-      : CI(CI), Diags(CI.getDiagnostics()), CodeGenOpts(CI.getCodeGenOpts()),
+      : CI(CI), Diags(CI.getDiagnostics()), CodeGenOpts(CGOpts),
         TargetOpts(CI.getTargetOpts()), LangOpts(CI.getLangOpts()),
         TheModule(M), VFS(std::move(VFS)),
         TargetTriple(TheModule->getTargetTriple()) {}
@@ -1363,14 +1364,14 @@ runThinLTOBackend(CompilerInstance &CI, ModuleSummaryIndex *CombinedIndex,
   }
 }
 
-void clang::emitBackendOutput(CompilerInstance &CI, StringRef TDesc,
-                              llvm::Module *M, BackendAction Action,
+void clang::emitBackendOutput(CompilerInstance &CI, CodeGenOptions &CGOpts,
+                              StringRef TDesc, llvm::Module *M,
+                              BackendAction Action,
                               IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
                               std::unique_ptr<raw_pwrite_stream> OS,
                               BackendConsumer *BC) {
   llvm::TimeTraceScope TimeScope("Backend");
   DiagnosticsEngine &Diags = CI.getDiagnostics();
-  const auto &CGOpts = CI.getCodeGenOpts();
 
   std::unique_ptr<llvm::Module> EmptyModule;
   if (!CGOpts.ThinLTOIndexFile.empty()) {
@@ -1410,7 +1411,7 @@ void clang::emitBackendOutput(CompilerInstance &CI, StringRef TDesc,
     }
   }
 
-  EmitAssemblyHelper AsmHelper(CI, M, VFS);
+  EmitAssemblyHelper AsmHelper(CI, CGOpts, M, VFS);
   AsmHelper.emitAssembly(Action, std::move(OS), BC);
 
   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's

clang/lib/CodeGen/CodeGenAction.cpp

@@ -312,7 +312,8 @@ void BackendConsumer::HandleTranslationUnit(ASTContext &C) {
 
   EmbedBitcode(getModule(), CodeGenOpts, llvm::MemoryBufferRef());
 
-  emitBackendOutput(CI, C.getTargetInfo().getDataLayoutString(), getModule(),
+  emitBackendOutput(CI, CI.getCodeGenOpts(),
+                    C.getTargetInfo().getDataLayoutString(), getModule(),
                     Action, FS, std::move(AsmOutStream), this);
 
   Ctx.setDiagnosticHandler(std::move(OldDiagnosticHandler));
@@ -1173,8 +1174,9 @@ void CodeGenAction::ExecuteAction() {
   std::unique_ptr<llvm::ToolOutputFile> OptRecordFile =
       std::move(*OptRecordFileOrErr);
 
-  emitBackendOutput(CI, CI.getTarget().getDataLayoutString(), TheModule.get(),
-                    BA, CI.getFileManager().getVirtualFileSystemPtr(),
+  emitBackendOutput(CI, CI.getCodeGenOpts(),
+                    CI.getTarget().getDataLayoutString(), TheModule.get(), BA,
+                    CI.getFileManager().getVirtualFileSystemPtr(),
                     std::move(OS));
   if (OptRecordFile)
     OptRecordFile->keep();

clang/lib/CodeGen/ObjectFilePCHContainerWriter.cpp

@@ -322,16 +322,16 @@ class PCHContainerGenerator : public ASTConsumer {
       // Print the IR for the PCH container to the debug output.
       llvm::SmallString<0> Buffer;
       clang::emitBackendOutput(
-          CI, Ctx.getTargetInfo().getDataLayoutString(), M.get(),
+          CI, CodeGenOpts, Ctx.getTargetInfo().getDataLayoutString(), M.get(),
           BackendAction::Backend_EmitLL, FS,
           std::make_unique<llvm::raw_svector_ostream>(Buffer));
       llvm::dbgs() << Buffer;
     });
 
     // Use the LLVM backend to emit the pch container.
-    clang::emitBackendOutput(CI, Ctx.getTargetInfo().getDataLayoutString(),
-                             M.get(), BackendAction::Backend_EmitObj, FS,
-                             std::move(OS));
+    clang::emitBackendOutput(CI, CodeGenOpts,
+                             Ctx.getTargetInfo().getDataLayoutString(), M.get(),
+                             BackendAction::Backend_EmitObj, FS, std::move(OS));
 
     // Free the memory for the temporary buffer.
     llvm::SmallVector<char, 0> Empty;

clang/test/Modules/gmodules-codegenopts.c

@@ -0,0 +1,18 @@
+// UNSUPPORTED: target={{.*}}-zos{{.*}}, target={{.*}}-aix{{.*}}
+// Check that the output from -gmodules can be loaded back by the compiler in
+// the presence of certain options like optimization level that could break
+// output. Note: without compiling twice the module is loaded from the in-memory
+// module cache not load it from the object container.
+
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -x objective-c -fmodules -fmodule-format=obj \
+// RUN:   -fimplicit-module-maps -fmodules-cache-path=%t %s \
+// RUN:   -I %S/Inputs -verify -O2
+
+// Compile again, confirming we can load the module.
+// RUN: %clang_cc1 -x objective-c -fmodules -fmodule-format=obj \
+// RUN:   -fimplicit-module-maps -fmodules-cache-path=%t %s \
+// RUN:   -I %S/Inputs -verify -O2
+
+@import DebugObjC;
+// expected-no-diagnostics