Revert "[DebugInfo] Make DIArgList inherit from Metadata and always unique" (#72682)

Reverts llvm/llvm-project#72147

Reverted due to buildbot failure:
https://lab.llvm.org/buildbot/#/builders/5/builds/38410

1 files changed, 8 insertions, 5 deletions

diff --git a/llvm/lib/IR/LLVMContextImpl.cpp b/llvm/lib/IR/LLVMContextImpl.cpp
index 993deaf..406850b 100644
--- a/llvm/lib/IR/LLVMContextImpl.cpp
+++ b/llvm/lib/IR/LLVMContextImpl.cpp
@@ -68,8 +68,15 @@ LLVMContextImpl::~LLVMContextImpl() {
 
   // Drop references for MDNodes.  Do this before Values get deleted to avoid
   // unnecessary RAUW when nodes are still unresolved.
-  for (auto *I : DistinctMDNodes)
+  for (auto *I : DistinctMDNodes) {
+    // We may have DIArgList that were uniqued, and as it has a custom
+    // implementation of dropAllReferences, it needs to be explicitly invoked.
+    if (auto *AL = dyn_cast<DIArgList>(I)) {
+      AL->dropAllReferences();
+      continue;
+    }
     I->dropAllReferences();
+  }
 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
   for (auto *I : CLASS##s)                                                     \
     I->dropAllReferences();
@@ -80,10 +87,6 @@ LLVMContextImpl::~LLVMContextImpl() {
     Pair.second->dropUsers();
   for (auto &Pair : MetadataAsValues)
     Pair.second->dropUse();
-  // Do not untrack ValueAsMetadata references for DIArgLists, as they have
-  // already been more efficiently untracked above.
-  for (DIArgList *AL : DIArgLists)
-    AL->dropAllReferences(/* Untrack */ false);
 
   // Destroy MDNodes.
   for (MDNode *I : DistinctMDNodes)