[ThinLTO] Summarize vcall_visibility metadata

Summary:
Second patch in series to support Safe Whole Program Devirtualization
Enablement, see RFC here:
http://lists.llvm.org/pipermail/llvm-dev/2019-December/137543.html

Summarize vcall_visibility metadata in ThinLTO global variable summary.

Depends on D71907.

Reviewers: pcc, evgeny777, steven_wu

Subscribers: mehdi_amini, Prazek, inglorion, hiraditya, dexonsmith, arphaman, ostannard, llvm-commits, cfe-commits, davidxl

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D71911

1 files changed, 8 insertions, 5 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index e89560b..6baa64a 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -985,9 +985,10 @@ static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
 
 // Decode the flags for GlobalVariable in the summary
 static GlobalVarSummary::GVarFlags getDecodedGVarFlags(uint64_t RawFlags) {
-  return GlobalVarSummary::GVarFlags((RawFlags & 0x1) ? true : false,
-                                     (RawFlags & 0x2) ? true : false,
-                                     (RawFlags & 0x4) ? true : false);
+  return GlobalVarSummary::GVarFlags(
+      (RawFlags & 0x1) ? true : false, (RawFlags & 0x2) ? true : false,
+      (RawFlags & 0x4) ? true : false,
+      (GlobalObject::VCallVisibility)(RawFlags >> 3));
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {
@@ -5969,7 +5970,8 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       unsigned RefArrayStart = 2;
       GlobalVarSummary::GVarFlags GVF(/* ReadOnly */ false,
                                       /* WriteOnly */ false,
-                                      /* Constant */ false);
+                                      /* Constant */ false,
+                                      GlobalObject::VCallVisibilityPublic);
       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
       if (Version >= 5) {
         GVF = getDecodedGVarFlags(Record[2]);
@@ -6106,7 +6108,8 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       unsigned RefArrayStart = 3;
       GlobalVarSummary::GVarFlags GVF(/* ReadOnly */ false,
                                       /* WriteOnly */ false,
-                                      /* Constant */ false);
+                                      /* Constant */ false,
+                                      GlobalObject::VCallVisibilityPublic);
       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
       if (Version >= 5) {
         GVF = getDecodedGVarFlags(Record[3]);