[libc-commits] [libc] [libc] Add posix_memalign as external entrypoint on Linux x86/ARM. (PR #185310)

[Alexey Samsonov via libc-commits]

https://github.com/vonosmas created https://github.com/llvm/llvm-project/pull/185310

`posix_memalign` is provided by Scudo allocator and is a part of POSIX standard, so we can safely declare it in the `<stdlib.h>` header on Linux systems.

>From 8cca619855e0508d3f4b2488bd51781c2b0dd135 Mon Sep 17 00:00:00 2001
From: Alexey Samsonov <vonosmas at gmail.com>
Date: Sun, 8 Mar 2026 18:16:46 +0000
Subject: [PATCH] [libc] Add posix_memalign as external entrypoint on Linux
 x86/ARM.

posix_memalign is provided by Scudo allocator and is a part
of POSIX standard, so we can safely declare it in the <stdlib.h> header
on Linux systems.
---
 libc/config/linux/aarch64/entrypoints.txt | 1 +
 libc/config/linux/x86_64/entrypoints.txt  | 1 +
 libc/src/stdlib/CMakeLists.txt            | 8 ++++++++
 3 files changed, 10 insertions(+)

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 960958b7cf90a..c43dc9dd0880b 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -213,6 +213,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.calloc
     libc.src.stdlib.free
     libc.src.stdlib.malloc
+    libc.src.stdlib.posix_memalign
     libc.src.stdlib.realloc
 
     # stdio.h entrypoints
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 4103ee0331a23..8468da12cdcce 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -216,6 +216,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.calloc
     libc.src.stdlib.free
     libc.src.stdlib.malloc
+    libc.src.stdlib.posix_memalign
     libc.src.stdlib.realloc
 
     # stdio.h entrypoints
diff --git a/libc/src/stdlib/CMakeLists.txt b/libc/src/stdlib/CMakeLists.txt
index 62da469f0eb9e..3872d05dcb6c9 100644
--- a/libc/src/stdlib/CMakeLists.txt
+++ b/libc/src/stdlib/CMakeLists.txt
@@ -492,6 +492,11 @@ if(NOT LIBC_TARGET_OS_IS_BAREMETAL AND NOT LIBC_TARGET_OS_IS_GPU)
       DEPENDS
         ${SCUDO_DEPS}
     )
+    add_entrypoint_external(
+      posix_memalign
+      DEPENDS
+        ${SCUDO_DEPS}
+    )
   else()
     add_entrypoint_external(
       malloc
@@ -511,6 +516,9 @@ if(NOT LIBC_TARGET_OS_IS_BAREMETAL AND NOT LIBC_TARGET_OS_IS_GPU)
     add_entrypoint_external(
       mallopt
     )
+    add_entrypoint_external(
+      posix_memalign
+    )
   endif()
 endif()