ThinLTOBitcodeWriter: Strip debug info from merged module.

This module will contain nothing but vtable definitions and (soon)
available_externally function definitions, so there is no point in keeping
debug info in the module.

Differential Revision: https://reviews.llvm.org/D28913

llvm-svn: 294511

llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp

@@ -19,6 +19,7 @@
 #include "llvm/Analysis/TypeMetadataUtils.h"
 #include "llvm/Bitcode/BitcodeWriter.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/PassManager.h"
@@ -261,6 +262,7 @@ void splitAndWriteThinLTOBitcode(raw_ostream &OS, Module &M) {
 
   ValueToValueMapTy VMap;
   std::unique_ptr<Module> MergedM(CloneModule(&M, VMap, IsInMergedM));
+  StripDebugInfo(*MergedM);
 
   filterModule(&M, [&](const GlobalValue *GV) { return !IsInMergedM(GV); });
 

llvm/test/Transforms/ThinLTOBitcodeWriter/split.ll

@@ -26,3 +26,10 @@ define i8* @f() {
 
 ; M1: !0 = !{i32 0, !"typeid"}
 !0 = !{i32 0, !"typeid"}
+
+; M0: !llvm.dbg.cu
+; M1-NOT: !llvm.dbg.cu
+!llvm.dbg.cu = !{}
+
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+!llvm.module.flags = !{!1}