[LTO][ThinLTO] Use the linker resolutions to mark global values as dso_local.

Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.

Differential Revision: https://reviews.llvm.org/D35702

llvm-svn: 317374

2 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index c2272260f44..d0f11db8f61 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -889,7 +889,9 @@ static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
   // to work correctly on earlier versions, we must conservatively treat all
   // values as live.
   bool Live = (RawFlags & 0x2) || Version < 3;
-  return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport, Live);
+  bool Local = (RawFlags & 0x4);
+
+  return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport, Live, Local);
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 1e491aa066e..c5d376c9426 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -955,6 +955,8 @@ static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
 
   RawFlags |= Flags.NotEligibleToImport; // bool
   RawFlags |= (Flags.Live << 1);
+  RawFlags |= (Flags.DSOLocal << 2);
+
   // Linkage don't need to be remapped at that time for the summary. Any future
   // change to the getEncodedLinkage() function will need to be taken into
   // account here as well.