[libc-commits] [libc] [libc] Add Elf32_Xword type (PR #177915)

Jakob Koschel via libc-commits libc-commits at lists.llvm.org
Mon Jan 26 01:38:30 PST 2026 

https://github.com/jakos-sec created https://github.com/llvm/llvm-project/pull/177915

In a recent PR (https://github.com/llvm/llvm-project/pull/174772), we introduced GnuPropertySection using ElfW(Xword). Since we are currently missing Elf32_Xword, this is failing on 32bit architectures.

This commit adds the missing Elf32_Xword type that should always hold 64bit even on 32bit architectures.

>From 6295df738a93281207f8d00d381cecea2a0086fe Mon Sep 17 00:00:00 2001
From: Jakob Koschel <jakobkoschel at google.com>
Date: Mon, 26 Jan 2026 09:34:03 +0000
Subject: [PATCH] [libc] Add Elf32_Xword type

In a recent PR, we introduced GnuPropertySection using ElfW(Xword).
Since we are currently missing Elf32_Xword, this is failing on 32bit
architectures.

This commit adds the missing Elf32_Xword type that should always hold
64bit even on 32bit architectures.
---
 libc/hdr/CMakeLists.txt                     |  1 +
 libc/hdr/types/CMakeLists.txt               |  8 ++++++++
 libc/hdr/types/Elf32_Xword.h                | 22 +++++++++++++++++++++
 libc/include/CMakeLists.txt                 |  3 ++-
 libc/include/elf.yaml                       |  1 +
 libc/include/llvm-libc-macros/link-macros.h |  1 +
 libc/include/llvm-libc-types/CMakeLists.txt |  1 +
 libc/include/llvm-libc-types/Elf32_Xword.h  | 16 +++++++++++++++
 8 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 libc/hdr/types/Elf32_Xword.h
 create mode 100644 libc/include/llvm-libc-types/Elf32_Xword.h

diff --git a/libc/hdr/CMakeLists.txt b/libc/hdr/CMakeLists.txt
index 1d78454ba9ffb..6362c10788b2b 100644
--- a/libc/hdr/CMakeLists.txt
+++ b/libc/hdr/CMakeLists.txt
@@ -294,6 +294,7 @@ add_gen_header(
     libc.include.llvm-libc-types.Elf32_Verneed
     libc.include.llvm-libc-types.Elf32_Versym
     libc.include.llvm-libc-types.Elf32_Word
+    libc.include.llvm-libc-types.Elf32_Xword
     libc.include.llvm-libc-types.Elf64_Addr
     libc.include.llvm-libc-types.Elf64_Chdr
     libc.include.llvm-libc-types.Elf64_Dyn
diff --git a/libc/hdr/types/CMakeLists.txt b/libc/hdr/types/CMakeLists.txt
index 362feefa67783..3385fe81fe223 100644
--- a/libc/hdr/types/CMakeLists.txt
+++ b/libc/hdr/types/CMakeLists.txt
@@ -648,6 +648,14 @@ add_proxy_header_library(
     libc.include.llvm-libc-types.Elf32_Word
 )
 
+add_proxy_header_library(
+  Elf32_Xword
+  HDRS
+  Elf32_Xword.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.Elf32_Xword
+)
+
 add_proxy_header_library(
   Elf64_Addr
   HDRS
diff --git a/libc/hdr/types/Elf32_Xword.h b/libc/hdr/types/Elf32_Xword.h
new file mode 100644
index 0000000000000..6daa7e9cdeab6
--- /dev/null
+++ b/libc/hdr/types/Elf32_Xword.h
@@ -0,0 +1,22 @@
+//===-- Proxy for Elf32_Xword ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_HDR_TYPES_ELF32_XWORD_H
+#define LLVM_LIBC_HDR_TYPES_ELF32_XWORD_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/Elf32_Xword.h"
+
+#else // Overlay mode
+
+#include <elf.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_ELF32_XWORD_H
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
index 1bc9c2ca1a51d..c6254aafe3849 100644
--- a/libc/include/CMakeLists.txt
+++ b/libc/include/CMakeLists.txt
@@ -497,6 +497,7 @@ add_header_macro(
     .llvm-libc-types.Elf32_Verneed
     .llvm-libc-types.Elf32_Versym
     .llvm-libc-types.Elf32_Word
+    .llvm-libc-types.Elf32_Xword
     .llvm-libc-types.Elf64_Addr
     .llvm-libc-types.Elf64_Chdr
     .llvm-libc-types.Elf64_Dyn
@@ -800,7 +801,7 @@ add_header_macro(
   ../libc/include/wctype.yaml
   wctype.h
   DEPENDS
-    .llvm_libc_common_h    
+    .llvm_libc_common_h
     .llvm-libc-types.wint_t
 )
 
diff --git a/libc/include/elf.yaml b/libc/include/elf.yaml
index fc0a8321666d0..6cb9122e013a9 100644
--- a/libc/include/elf.yaml
+++ b/libc/include/elf.yaml
@@ -461,6 +461,7 @@ types:
   - type_name: Elf32_Verneed
   - type_name: Elf32_Versym
   - type_name: Elf32_Word
+  - type_name: Elf32_Xword
   - type_name: Elf64_Addr
   - type_name: Elf64_Chdr
   - type_name: Elf64_Dyn
diff --git a/libc/include/llvm-libc-macros/link-macros.h b/libc/include/llvm-libc-macros/link-macros.h
index 1876a6dc848d1..7430e5268b104 100644
--- a/libc/include/llvm-libc-macros/link-macros.h
+++ b/libc/include/llvm-libc-macros/link-macros.h
@@ -24,6 +24,7 @@
 #include "../llvm-libc-types/Elf32_Sword.h"
 #include "../llvm-libc-types/Elf32_Sym.h"
 #include "../llvm-libc-types/Elf32_Word.h"
+#include "../llvm-libc-types/Elf32_Xword.h"
 #include "../llvm-libc-types/Elf64_Addr.h"
 #include "../llvm-libc-types/Elf64_Chdr.h"
 #include "../llvm-libc-types/Elf64_Dyn.h"
diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
index 3124fdc33fbc2..dc36dfeadba57 100644
--- a/libc/include/llvm-libc-types/CMakeLists.txt
+++ b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -194,6 +194,7 @@ add_header(Elf32_Lword HDR Elf32_Lword.h DEPENDS libc.include.llvm-libc-macros.s
 add_header(Elf32_Off HDR Elf32_Off.h DEPENDS libc.include.llvm-libc-macros.stdint_macros)
 add_header(Elf32_Sword HDR Elf32_Sword.h DEPENDS libc.include.llvm-libc-macros.stdint_macros)
 add_header(Elf32_Word HDR Elf32_Word.h DEPENDS libc.include.llvm-libc-macros.stdint_macros)
+add_header(Elf32_Xword HDR Elf32_Xword.h DEPENDS libc.include.llvm-libc-macros.stdint_macros)
 add_header(
   Elf32_Chdr
   HDR
diff --git a/libc/include/llvm-libc-types/Elf32_Xword.h b/libc/include/llvm-libc-types/Elf32_Xword.h
new file mode 100644
index 0000000000000..9a4898043b041
--- /dev/null
+++ b/libc/include/llvm-libc-types/Elf32_Xword.h
@@ -0,0 +1,16 @@
+//===-- Definition of Elf32_Xword type ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES_ELF32_XWORD_H
+#define LLVM_LIBC_TYPES_ELF32_XWORD_H
+
+#include "../llvm-libc-macros/stdint-macros.h"
+
+typedef uint64_t Elf32_Xword;
+
+#endif // LLVM_LIBC_TYPES_ELF32_XWORD_H

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