[libc][annex_k] Add errno_t.

[bassiounix]

RFC https://discourse.llvm.org/t/rfc-bounds-checking-interfaces-for-llvm-libc/87685

Add errno_t type required by Annex K interface in LLVM libc.

[bassiounix]

• [libc][annex_k] Add constraint_handler_t. #163239
• [libc][annex_k] Add rsize_t. #163238
• [libc][annex_k] Add Annex K support macros. #163100
• [libc][annex_k] Add errno_t. #163094 👈 (View in Graphite)
• main

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[llvmbot]

@llvm/pr-subscribers-libc

Author: Muhammad Bassiouni (bassiounix)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/163094.diff

6 Files Affected:

• (modified) libc/hdr/types/CMakeLists.txt (+9)
• (added) libc/hdr/types/errno_t.h (+18)
• (modified) libc/include/CMakeLists.txt (+1)
• (modified) libc/include/errno.h.def (+2)
• (modified) libc/include/llvm-libc-types/CMakeLists.txt (+2)
• (added) libc/include/llvm-libc-types/errno_t.h (+18)

diff --git a/libc/hdr/types/CMakeLists.txt b/libc/hdr/types/CMakeLists.txt
index 21971a4004760..89414f419a7f0 100644
--- a/libc/hdr/types/CMakeLists.txt
+++ b/libc/hdr/types/CMakeLists.txt
@@ -162,6 +162,15 @@ add_proxy_header_library(
     libc.include.fcntl
 )
 
+add_proxy_header_library(
+  errno_t
+  HDRS
+    errno_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.errno_t
+    libc.include.errno
+)
+
 add_proxy_header_library(
   fenv_t
   HDRS
diff --git a/libc/hdr/types/errno_t.h b/libc/hdr/types/errno_t.h
new file mode 100644
index 0000000000000..91706b05c9155
--- /dev/null
+++ b/libc/hdr/types/errno_t.h
@@ -0,0 +1,18 @@
+//===-- Proxy for errno_t -------------------------------------------------===//
+//
+// 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_ERRNO_T_H
+#define LLVM_LIBC_HDR_TYPES_ERRNO_T_H
+
+#define LIBC_HAS_ANNEX_K
+
+#include "include/llvm-libc-types/errno_t.h"
+
+#undef LIBC_HAS_ANNEX_K
+
+#endif // LLVM_LIBC_HDR_TYPES_ERRNO_T_H
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
index afa90e6c8b655..a6715392fe7a1 100644
--- a/libc/include/CMakeLists.txt
+++ b/libc/include/CMakeLists.txt
@@ -302,6 +302,7 @@ add_header_macro(
   DEPENDS
     .llvm-libc-macros.generic_error_number_macros
     .llvm-libc-macros.error_number_macros
+    .llvm-libc-types.errno_t
 )
 
 add_header_macro(
diff --git a/libc/include/errno.h.def b/libc/include/errno.h.def
index aa1f6c9e48444..35341c60e38b2 100644
--- a/libc/include/errno.h.def
+++ b/libc/include/errno.h.def
@@ -33,4 +33,6 @@ __END_C_DECLS
 
 #define errno (*__llvm_libc_errno())
 
+#include "llvm-libc-types/errno_t.h"
+
 #endif // LLVM_LIBC_ERRNO_H
diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
index 70da983be9090..670ab71468661 100644
--- a/libc/include/llvm-libc-types/CMakeLists.txt
+++ b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -296,3 +296,5 @@ add_header(EFI_SYSTEM_TABLE
     .EFI_TABLE_HEADER
     .char16_t
 )
+
+add_header(errno_t HDR errno_t.h)
diff --git a/libc/include/llvm-libc-types/errno_t.h b/libc/include/llvm-libc-types/errno_t.h
new file mode 100644
index 0000000000000..f99fe1266ccd1
--- /dev/null
+++ b/libc/include/llvm-libc-types/errno_t.h
@@ -0,0 +1,18 @@
+//===-- Definition of type errno_t ----------------------------------------===//
+//
+// 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_INCLUDE_LLVM_LIBC_TYPES_ERRNO_T_H
+#define LLVM_LIBC_INCLUDE_LLVM_LIBC_TYPES_ERRNO_T_H
+
+#ifdef LIBC_HAS_ANNEX_K
+
+typedef int errno_t;
+
+#endif // LIBC_HAS_ANNEX_K
+
+#endif // LLVM_LIBC_INCLUDE_LLVM_LIBC_TYPES_ERRNO_T_H

[michaelrj-google]

I don't think we need the check if annex K is enabled on the types, since they're fairly trivial.

[bassiounix]

This would mean to include types without _s functions even when it's not wanted with the macro. This is not a desired behavior as https://github.com/llvm/llvm-project/blob/b841bdd129de44b674ffd328ef98cf9566a322ca/clang/lib/Headers/stdint.h#L788-L792 checks first that it should be included.