[llvm] [llvm][MetadataLoader] Make sure we correctly load DW_APPLE_ENUM_KIND from bitcode (PR #132374)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-debuginfo

Author: Michael Buch (Michael137)

<details>
<summary>Changes</summary>

This was pointed out in
https://github.com/llvm/llvm-project/pull/124752#issuecomment-2730052773

There was not test that roundtrips this attribute through LLVM bitcode, so this was never caught.

---
Full diff: https://github.com/llvm/llvm-project/pull/132374.diff


2 Files Affected:

- (modified) llvm/lib/Bitcode/Reader/MetadataLoader.cpp (+2-2) 
- (modified) llvm/test/DebugInfo/AArch64/DW_AT_APPLE_enum_kind.ll (+3-2) 


``````````diff
diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
index 1baf0a9214e00..12794d3346e3f 100644
--- a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -1704,8 +1704,8 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
       }
     }
 
-    if (Record.size() > 25 && Record[25] != dwarf::DW_APPLE_ENUM_KIND_invalid)
-      EnumKind = Record[25];
+    if (Record.size() > 24 && Record[24] != dwarf::DW_APPLE_ENUM_KIND_invalid)
+      EnumKind = Record[24];
 
     DICompositeType *CT = nullptr;
     if (Identifier)
diff --git a/llvm/test/DebugInfo/AArch64/DW_AT_APPLE_enum_kind.ll b/llvm/test/DebugInfo/AArch64/DW_AT_APPLE_enum_kind.ll
index 399d80c778072..4f219a7e7b12e 100644
--- a/llvm/test/DebugInfo/AArch64/DW_AT_APPLE_enum_kind.ll
+++ b/llvm/test/DebugInfo/AArch64/DW_AT_APPLE_enum_kind.ll
@@ -1,5 +1,6 @@
-; RUN: llc < %s -filetype=obj -o %t
-; RUN: llvm-dwarfdump -v %t | FileCheck %s
+; RUN: clang++ %s -c -g -emit-llvm -o %t.bc
+; RUN: llc %t.bc -filetype=obj -o %t.o
+; RUN: llvm-dwarfdump -v %t.o | FileCheck %s
 
 ; C++ source to regenerate:
 ; enum __attribute__((enum_extensibility(open))) OpenEnum {

``````````

</details>


https://github.com/llvm/llvm-project/pull/132374