[libc] Reapply ELF/LINK header changes

[SchrodingerZhu]

This is based on @izaakschroeder previous patch but I only select macro definitions for now. We need these definitions for VDSO work, which has been delayed for a very long time.

Co-Authored-by: Izaak Schroeder [email protected]

[llvmbot]

@llvm/pr-subscribers-libc

Author: Schrodinger ZHU Yifan (SchrodingerZhu)

Changes

This is based on @izaakschroeder previous patch but I only select macro definitions for now. We need these definitions for VDSO work, which has been delayed for a very long time.

Co-Authored-by: Izaak Schroeder <[email protected]>

---

Full diff: https://github.com/llvm/llvm-project/pull/102765.diff

10 Files Affected:

• (modified) libc/config/linux/aarch64/headers.txt (+2)
• (modified) libc/config/linux/x86_64/headers.txt (+2)
• (modified) libc/include/CMakeLists.txt (+17)
• (added) libc/include/elf.h.def (+17)
• (added) libc/include/link.h.def (+17)
• (modified) libc/include/llvm-libc-macros/CMakeLists.txt (+6)
• (added) libc/include/llvm-libc-macros/elf-macros.h (+18)
• (modified) libc/include/llvm-libc-macros/link-macros.h (+9-2)
• (added) libc/newhdrgen/yaml/elf.yaml (+8)
• (added) libc/newhdrgen/yaml/link.yaml (+8)

diff --git a/libc/config/linux/aarch64/headers.txt b/libc/config/linux/aarch64/headers.txt
index 8f898f0150905a..ebe053af99d803 100644
--- a/libc/config/linux/aarch64/headers.txt
+++ b/libc/config/linux/aarch64/headers.txt
@@ -2,6 +2,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.assert
     libc.include.ctype
     libc.include.dlfcn
+    libc.include.elf
     libc.include.errno
     libc.include.features
     libc.include.fenv
@@ -9,6 +10,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.stdint
     libc.include.inttypes
     libc.include.limits
+    libc.include.link
     libc.include.math
     libc.include.pthread
     libc.include.signal
diff --git a/libc/config/linux/x86_64/headers.txt b/libc/config/linux/x86_64/headers.txt
index 0294f62bc2f7a0..77e454e64395df 100644
--- a/libc/config/linux/x86_64/headers.txt
+++ b/libc/config/linux/x86_64/headers.txt
@@ -3,6 +3,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.ctype
     libc.include.dirent
     libc.include.dlfcn
+    libc.include.elf
     libc.include.errno
     libc.include.fcntl
     libc.include.features
@@ -11,6 +12,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.stdint
     libc.include.inttypes
     libc.include.limits
+    libc.include.link
     libc.include.math
     libc.include.pthread
     libc.include.sched
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
index cbde24e17619f6..2b6eb61782a632 100644
--- a/libc/include/CMakeLists.txt
+++ b/libc/include/CMakeLists.txt
@@ -420,6 +420,23 @@ add_header_macro(
     .llvm-libc-types.posix_spawn_file_actions_t
 )
 
+add_gen_header(
+  link
+  DEF_FILE link.h.def
+  GEN_HDR link.h
+  DEPENDS
+    .llvm_libc_common_h
+    .llvm-libc-macros.link_macros
+)
+
+add_gen_header(
+  elf
+  DEF_FILE elf.h.def
+  GEN_HDR elf.h
+  DEPENDS
+    .llvm-libc-macros.elf_macros
+)
+
 # TODO: Not all platforms will have a include/sys directory. Add the sys
 # directory and the targets for sys/*.h files conditional to the OS requiring
 # them.
diff --git a/libc/include/elf.h.def b/libc/include/elf.h.def
new file mode 100644
index 00000000000000..b9b2604fc7167b
--- /dev/null
+++ b/libc/include/elf.h.def
@@ -0,0 +1,17 @@
+//===-- System V header elf.h ---------------------------------------------===//
+//
+// 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_ELF_H
+#define LLVM_LIBC_ELF_H
+
+#include "__llvm-libc-common.h"
+#include "llvm-libc-macros/elf-macros.h"
+
+%%public_api()
+
+#endif // LLVM_LIBC_ELF_H
diff --git a/libc/include/link.h.def b/libc/include/link.h.def
new file mode 100644
index 00000000000000..ebab81c841b8dd
--- /dev/null
+++ b/libc/include/link.h.def
@@ -0,0 +1,17 @@
+//===-- GNU header link.h -------------------------------------------------===//
+//
+// 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_LINK_H
+#define LLVM_LIBC_LINK_H
+
+#include "__llvm-libc-common.h"
+#include "llvm-libc-macros/link-macros.h"
+
+%%public_api()
+
+#endif // LLVM_LIBC_LINK_H
diff --git a/libc/include/llvm-libc-macros/CMakeLists.txt b/libc/include/llvm-libc-macros/CMakeLists.txt
index 3c10abef8768c0..60a8725f9ef63f 100644
--- a/libc/include/llvm-libc-macros/CMakeLists.txt
+++ b/libc/include/llvm-libc-macros/CMakeLists.txt
@@ -289,3 +289,9 @@ add_macro_header(
   HDR
     dlfcn-macros.h
 )
+
+add_macro_header(
+  elf_macros
+  HDR
+    elf-macros.h
+)
diff --git a/libc/include/llvm-libc-macros/elf-macros.h b/libc/include/llvm-libc-macros/elf-macros.h
new file mode 100644
index 00000000000000..fa4442abf0f5ce
--- /dev/null
+++ b/libc/include/llvm-libc-macros/elf-macros.h
@@ -0,0 +1,18 @@
+//===-- Definition of macros from elf.h -----------------------------------===//
+//
+// 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_MACROS_ELF_MACROS_H
+#define LLVM_LIBC_MACROS_ELF_MACROS_H
+
+#if __has_include(<linux/elf.h>)
+#include <linux/elf.h>
+#else
+#error "cannot use <sys/elf.h> without proper system headers."
+#endif
+
+#endif // LLVM_LIBC_MACROS_ELF_MACROS_H
diff --git a/libc/include/llvm-libc-macros/link-macros.h b/libc/include/llvm-libc-macros/link-macros.h
index 5c8cadab8e71cb..89e7bb50aa5566 100644
--- a/libc/include/llvm-libc-macros/link-macros.h
+++ b/libc/include/llvm-libc-macros/link-macros.h
@@ -6,8 +6,15 @@
 //
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_LIBC_MACROS_LINK_MACROS_H
+#define LLVM_LIBC_MACROS_LINK_MACROS_H
+
+#include "elf-macros.h"
+
 #ifdef __LP64__
-#define ElfW(type) Elf64_ ## type
+#define ElfW(type) Elf64_##type
 #else
-#define ElfW(type) Elf32_ ## type
+#define ElfW(type) Elf32_##type
+#endif
+
 #endif
diff --git a/libc/newhdrgen/yaml/elf.yaml b/libc/newhdrgen/yaml/elf.yaml
new file mode 100644
index 00000000000000..2e9db329e22979
--- /dev/null
+++ b/libc/newhdrgen/yaml/elf.yaml
@@ -0,0 +1,8 @@
+header: elf.h
+standards:
+  - Linux
+macros: []
+types: []
+enums: []
+objects: []
+functions: []
diff --git a/libc/newhdrgen/yaml/link.yaml b/libc/newhdrgen/yaml/link.yaml
new file mode 100644
index 00000000000000..d1963a86813af3
--- /dev/null
+++ b/libc/newhdrgen/yaml/link.yaml
@@ -0,0 +1,8 @@
+header: link.h
+standards:
+  - Linux
+macros: []
+types: []
+enums: []
+objects: []
+functions: []

[SchrodingerZhu]

@jhuber6 I think we still need this. elf.h, link.h are to be exposed to users. LLVM's ELF.h is good for internal usage but end users should not see specialized definitions inside such headers.