[libcxx-commits] [libcxx] [libc++] increase minimum deployment target on macOS to 11.0 (PR #176094)

[via libcxx-commits]

https://github.com/h-vetinari created https://github.com/llvm/llvm-project/pull/176094

#166172 moved the effective minimum deployment target on macOS to 10.15 (because `aligned_alloc` is not defined before that in the C stdlib), and indeed, @philnik777 said in that PR
> [...] libc++ only supports macOS 11 and later.

I've seen no discussion of this (closest PR seems to be #161640), the docs and release notes do not mention it (in contrast, there was an [announcement](https://discourse.llvm.org/t/libc-bumping-minimal-deployment-target-for-building-the-dylib-static-library-on-macos/68912) the last time the deployment target was increased), and indeed, `availability.h` only enforces the minimum of 10.13:
https://github.com/llvm/llvm-project/blob/2fa1ba62ac92fe95613d980e38ac2db36141fee8/libcxx/include/__configuration/availability.h#L199-L205

This PR attempts to rectify at least the documentation part; I assume the other targets in the condition above would also need to be updated, but I don't know the right versions for that.

PS. To avoid any misunderstandings, I'm neutral on increasing the deployment target[^1], just trying to reflect the state of things accurately before the v22 release.

[^1]: that is to say, I'm definitely not advocating for this.


>From edb881bfa2b200db6b4aa6052cd763beba1ce3b6 Mon Sep 17 00:00:00 2001
From: "H. Vetinari" <h.vetinari at gmx.com>
Date: Thu, 15 Jan 2026 17:20:12 +1100
Subject: [PATCH] [libc++] increase minimum deployment target on macOS to 11.0

---
 libcxx/docs/ReleaseNotes/22.rst               | 2 ++
 libcxx/docs/index.rst                         | 2 +-
 libcxx/include/__configuration/availability.h | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/libcxx/docs/ReleaseNotes/22.rst b/libcxx/docs/ReleaseNotes/22.rst
index 4d56c82a53170..e9c61594fa61d 100644
--- a/libcxx/docs/ReleaseNotes/22.rst
+++ b/libcxx/docs/ReleaseNotes/22.rst
@@ -107,6 +107,8 @@ Improvements and New Features
 Deprecations and Removals
 -------------------------
 
+- The minimally supported deployment target on macOS has been increased to 11.0.
+
 Potentially breaking changes
 ----------------------------
 
diff --git a/libcxx/docs/index.rst b/libcxx/docs/index.rst
index a9f0a04eeb808..4069639dbb6b6 100644
--- a/libcxx/docs/index.rst
+++ b/libcxx/docs/index.rst
@@ -142,7 +142,7 @@ Libc++ also supports common platforms and architectures:
 ===================== ========================= ============================
 Target platform       Target architecture       Notes
 ===================== ========================= ============================
-macOS 10.13+          i386, x86_64, arm64
+macOS 11.0+           i386, x86_64, arm64
 FreeBSD 12+           i386, x86_64, arm
 Linux                 i386, x86_64, arm, arm64  Only glibc-2.24 and later and no other libc is officially supported
 Android 5.0+          i386, x86_64, arm, arm64
diff --git a/libcxx/include/__configuration/availability.h b/libcxx/include/__configuration/availability.h
index 2c76347090fca..b8bd0ec46293d 100644
--- a/libcxx/include/__configuration/availability.h
+++ b/libcxx/include/__configuration/availability.h
@@ -196,7 +196,7 @@
     __attribute__((availability(bridgeos, strict, introduced = 6.0)))                                             \
     __attribute__((availability(driverkit, strict, introduced = 21.3)))
 
-#  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)  && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__  < 101300) || \
+#  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)  && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__  < 110000) || \
       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 150000) || \
       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__)     && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__     < 150000) || \
       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__)  && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__  < 70000)  || \