[LTO] Add option to generate optimization records

It is used to drive this from the clang driver via -mllvm.

Same option name is used as in opt.

Differential Revision: https://reviews.llvm.org/D26832

llvm-svn: 287356

1 files changed, 34 insertions, 0 deletions

diff --git a/llvm/lib/LTO/LTOCodeGenerator.cpp b/llvm/lib/LTO/LTOCodeGenerator.cpp
index 75810643b9c..d2f964e4d24 100644
--- a/llvm/lib/LTO/LTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/LTOCodeGenerator.cpp
@@ -49,6 +49,7 @@
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/ToolOutputFile.h"
+#include "llvm/Support/YAMLTraits.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetOptions.h"
@@ -92,6 +93,11 @@ cl::opt<bool> LTOStripInvalidDebugInfo(
     cl::Hidden);
 }
 
+static cl::opt<std::string>
+    RemarksFilename("pass-remarks-output",
+                    cl::desc("Output filename for pass remarks"),
+                    cl::value_desc("filename"));
+
 LTOCodeGenerator::LTOCodeGenerator(LLVMContext &Context)
     : Context(Context), MergedModule(new Module("ld-temp.o", Context)),
       TheLinker(new Linker(*MergedModule)) {
@@ -495,6 +501,29 @@ void LTOCodeGenerator::verifyMergedModuleOnce() {
     report_fatal_error("Broken module found, compilation aborted!");
 }
 
+bool LTOCodeGenerator::setupOptimizationRemarks() {
+  if (RemarksFilename != "") {
+    std::error_code EC;
+    DiagnosticOutputFile = llvm::make_unique<tool_output_file>(
+        RemarksFilename, EC, sys::fs::F_None);
+    if (EC) {
+      emitError(EC.message());
+      return false;
+    }
+    Context.setDiagnosticsOutputFile(
+        new yaml::Output(DiagnosticOutputFile->os()));
+  }
+  return true;
+}
+
+void LTOCodeGenerator::finishOptimizationRemarks() {
+  if (DiagnosticOutputFile) {
+    DiagnosticOutputFile->keep();
+    // FIXME: LTOCodeGenerator dtor is not invoked on Darwin
+    DiagnosticOutputFile->os().flush();
+  }
+}
+
 /// Optimize merged modules using various IPO passes
 bool LTOCodeGenerator::optimize(bool DisableVerify, bool DisableInline,
                                 bool DisableGVNLoadPRE,
@@ -502,6 +531,9 @@ bool LTOCodeGenerator::optimize(bool DisableVerify, bool DisableInline,
   if (!this->determineTarget())
     return false;
 
+  if (!setupOptimizationRemarks())
+    return false;
+
   // We always run the verifier once on the merged module, the `DisableVerify`
   // parameter only applies to subsequent verify.
   verifyMergedModuleOnce();
@@ -535,6 +567,8 @@ bool LTOCodeGenerator::optimize(bool DisableVerify, bool DisableInline,
   // Run our queue of passes all at once now, efficiently.
   passes.run(*MergedModule);
 
+  finishOptimizationRemarks();
+
   return true;
 }