[asan] In llvm.asan.globals, allow entries to be non-GlobalVariable and skip over them

Looks like there are valid reasons why we need to allow bitcasts in llvm.asan.globals, see discussion at https://github.com/apple/swift-llvm/pull/133. Let's look through bitcasts when iterating over entries in the llvm.asan.globals list.

Differential Revision: https://reviews.llvm.org/D55794

llvm-svn: 349544

1 files changed, 4 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index a5c64f354f4..769cd2343e0 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -441,8 +441,11 @@ public:
     for (auto MDN : Globals->operands()) {
       // Metadata node contains the global and the fields of "Entry".
       assert(MDN->getNumOperands() == 5);
-      auto *GV = mdconst::extract_or_null<GlobalVariable>(MDN->getOperand(0));
+      auto *V = mdconst::extract_or_null<Constant>(MDN->getOperand(0));
       // The optimizer may optimize away a global entirely.
+      if (!V) continue;
+      auto *StrippedV = V->stripPointerCasts();
+      auto *GV = dyn_cast<GlobalVariable>(StrippedV);
       if (!GV) continue;
       // We can already have an entry for GV if it was merged with another
       // global.