ModuleUtils: Stop using comdat members to generate unique module ids.

It is possible for two modules to define the same set of external
symbols without causing a duplicate symbol error at link time,
as long as each of the symbols is a comdat member. So we cannot
use them as part of a unique id for the module.

Differential Revision: https://reviews.llvm.org/D38602

llvm-svn: 315026

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
index 2ef3d6336ae..ba4b7f3cc26 100644
--- a/llvm/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
@@ -243,7 +243,7 @@ std::string llvm::getUniqueModuleId(Module *M) {
   bool ExportsSymbols = false;
   auto AddGlobal = [&](GlobalValue &GV) {
     if (GV.isDeclaration() || GV.getName().startswith("llvm.") ||
-        !GV.hasExternalLinkage())
+        !GV.hasExternalLinkage() || GV.hasComdat())
       return;
     ExportsSymbols = true;
     Md5.update(GV.getName());