[llvm-link] Fix crash when materializing appending global

This patch fixes llvm-link crash when materializing global variable
with appending linkage and initializer that depends on another
global with appending linkage.

Reviewed By: tra

Differential Revision: https://reviews.llvm.org/D95329

1 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Utils/ValueMapper.cpp b/llvm/lib/Transforms/Utils/ValueMapper.cpp
index 8ab272e..930e0b7 100644
--- a/llvm/lib/Transforms/Utils/ValueMapper.cpp
+++ b/llvm/lib/Transforms/Utils/ValueMapper.cpp
@@ -819,11 +819,15 @@ void Mapper::flush() {
       break;
     case WorklistEntry::MapAppendingVar: {
       unsigned PrefixSize = AppendingInits.size() - E.AppendingGVNumNewMembers;
+      // mapAppendingVariable call can change AppendingInits if initalizer for
+      // the variable depends on another appending global, because of that inits
+      // need to be extracted and updated before the call.
+      SmallVector<Constant *, 8> NewInits(
+          drop_begin(AppendingInits, PrefixSize));
+      AppendingInits.resize(PrefixSize);
       mapAppendingVariable(*E.Data.AppendingGV.GV,
                            E.Data.AppendingGV.InitPrefix,
-                           E.AppendingGVIsOldCtorDtor,
-                           makeArrayRef(AppendingInits).slice(PrefixSize));
-      AppendingInits.resize(PrefixSize);
+                           E.AppendingGVIsOldCtorDtor, makeArrayRef(NewInits));
       break;
     }
     case WorklistEntry::MapGlobalIndirectSymbol: