[LTO] Load sample profile in LTO link step.

Summary:
Load sample profile in LTO link step.
ThinLTO calls populateModulePassManager to load the profile

Reviewers: tejohnson, davidxl, danielcdh

Subscribers: mehdi_amini, inglorion, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D54564

llvm-svn: 346971

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 19ff2a21cd2..4a6b4aa1d56 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -747,6 +747,12 @@ void PassManagerBuilder::populateModulePassManager(
 }
 
 void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
+  // Load sample profile before running the LTO optimization pipeline.
+  if (!PGOSampleUse.empty()) {
+    PM.add(createPruneEHPass());
+    PM.add(createSampleProfileLoaderPass(PGOSampleUse));
+  }
+
   // Remove unused virtual tables to improve the quality of code generated by
   // whole-program devirtualization and bitset lowering.
   PM.add(createGlobalDCEPass());