Add comdat key field to llvm.global_ctors and llvm.global_dtors

This allows us to put dynamic initializers for weak data into the same
comdat group as the data being initialized.  This is necessary for MSVC
ABI compatibility.  Once we have comdats for guard variables, we can use
the combination to help GlobalOpt fire more often for weak data with
guarded initialization on other platforms.

Reviewers: nlewycky

Differential Revision: http://reviews.llvm.org/D3499

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209015 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 14546c0fe4..a2bb52c1e9 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1700,8 +1700,11 @@ error_code BitcodeReader::GlobalCleanup() {
   // Look for global variables which need to be renamed.
   for (Module::global_iterator
          GI = TheModule->global_begin(), GE = TheModule->global_end();
-       GI != GE; ++GI)
-    UpgradeGlobalVariable(GI);
+       GI != GE;) {
+    GlobalVariable *GV = GI++;
+    UpgradeGlobalVariable(GV);
+  }
+
   // Force deallocation of memory for these vectors to favor the client that
   // want lazy deserialization.
   std::vector<std::pair<GlobalVariable*, unsigned> >().swap(GlobalInits);