IR: Allow multiple global metadata attachments with the same type.

This will be necessary to allow the global merge pass to attach
multiple debug info metadata nodes to global variables once we reverse
the edge from DIGlobalVariable to GlobalVariable.

Differential Revision: http://reviews.llvm.org/D20414

llvm-svn: 271358

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index c47bb2518e0..fbf73509403 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -1991,6 +1991,7 @@ void Verifier::visitFunction(const Function &F) {
              "blockaddress may not be used with the entry block!", Entry);
     }
 
+    unsigned NumDebugAttachments = 0;
     // Visit metadata attachments.
     for (const auto &I : MDs) {
       // Verify that the attachment is legal.
@@ -1998,6 +1999,9 @@ void Verifier::visitFunction(const Function &F) {
       default:
         break;
       case LLVMContext::MD_dbg:
+        ++NumDebugAttachments;
+        AssertDI(NumDebugAttachments == 1,
+                 "function must have a single !dbg attachment", &F, I.second);
         AssertDI(isa<DISubprogram>(I.second),
                  "function !dbg attachment must be a subprogram", &F, I.second);
         break;