[libcxx-commits] [libcxx] [libc++] Move compiler-detection Lit features first (PR #73544)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne created https://github.com/llvm/llvm-project/pull/73544

Lit features are evaluated in order. Some checks may require the compiler detection to have run first in order to work properly, for example some checks being added in https://reviews.llvm.org/D154246 which require GCC to have been detected. It is kind of brittle to rely on such ordering, but in practice moving the compiler detection first should never hurt.

>From 9f9c52904352e88e892257e57ec3fe4eee684890 Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne.2 at gmail.com>
Date: Mon, 27 Nov 2023 11:57:46 -0500
Subject: [PATCH] [libc++] Move compiler-detection Lit features first

Lit features are evaluated in order. Some checks may require the compiler
detection to have run first in order to work properly, for example some
checks being added in https://reviews.llvm.org/D154246 which require GCC
to have been detected. It is kind of brittle to rely on such ordering,
but in practice moving the compiler detection first should never hurt.
---
 libcxx/utils/libcxx/test/features.py | 113 ++++++++++++++-------------
 1 file changed, 57 insertions(+), 56 deletions(-)

diff --git a/libcxx/utils/libcxx/test/features.py b/libcxx/utils/libcxx/test/features.py
index e854aed66513806..33645085ec34ccb 100644
--- a/libcxx/utils/libcxx/test/features.py
+++ b/libcxx/utils/libcxx/test/features.py
@@ -60,6 +60,63 @@ def _getAndroidDeviceApi(cfg):
 
 
 DEFAULT_FEATURES = [
+    Feature(name="apple-clang", when=_isAppleClang),
+    Feature(
+        name=lambda cfg: "apple-clang-{__clang_major__}".format(**compilerMacros(cfg)),
+        when=_isAppleClang,
+    ),
+    Feature(
+        name=lambda cfg: "apple-clang-{__clang_major__}.{__clang_minor__}".format(**compilerMacros(cfg)),
+        when=_isAppleClang,
+    ),
+    Feature(
+        name=lambda cfg: "apple-clang-{__clang_major__}.{__clang_minor__}.{__clang_patchlevel__}".format(**compilerMacros(cfg)),
+        when=_isAppleClang,
+    ),
+    Feature(name="clang", when=_isClang),
+    Feature(
+        name=lambda cfg: "clang-{__clang_major__}".format(**compilerMacros(cfg)),
+        when=_isClang,
+    ),
+    Feature(
+        name=lambda cfg: "clang-{__clang_major__}.{__clang_minor__}".format(**compilerMacros(cfg)),
+        when=_isClang,
+    ),
+    Feature(
+        name=lambda cfg: "clang-{__clang_major__}.{__clang_minor__}.{__clang_patchlevel__}".format(**compilerMacros(cfg)),
+        when=_isClang,
+    ),
+    # Note: Due to a GCC bug (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104760), we must disable deprecation warnings
+    #       on GCC or spurious diagnostics are issued.
+    #
+    # TODO:
+    # - Enable -Wplacement-new with GCC.
+    # - Enable -Wclass-memaccess with GCC.
+    Feature(
+        name="gcc",
+        when=_isGCC,
+        actions=[
+            AddCompileFlag("-D_LIBCPP_DISABLE_DEPRECATION_WARNINGS"),
+            AddCompileFlag("-Wno-placement-new"),
+            AddCompileFlag("-Wno-class-memaccess"),
+            AddFeature("GCC-ALWAYS_INLINE-FIXME"),
+        ],
+    ),
+    Feature(
+        name=lambda cfg: "gcc-{__GNUC__}".format(**compilerMacros(cfg)), when=_isGCC
+    ),
+    Feature(
+        name=lambda cfg: "gcc-{__GNUC__}.{__GNUC_MINOR__}".format(**compilerMacros(cfg)),
+        when=_isGCC,
+    ),
+    Feature(
+        name=lambda cfg: "gcc-{__GNUC__}.{__GNUC_MINOR__}.{__GNUC_PATCHLEVEL__}".format(**compilerMacros(cfg)),
+        when=_isGCC,
+    ),
+    Feature(name="msvc", when=_isMSVC),
+    Feature(name=lambda cfg: "msvc-{}".format(*_msvcVersion(cfg)), when=_isMSVC),
+    Feature(name=lambda cfg: "msvc-{}.{}".format(*_msvcVersion(cfg)), when=_isMSVC),
+
     Feature(
         name="thread-safety",
         when=lambda cfg: hasCompileFlag(cfg, "-Werror=thread-safety"),
@@ -231,62 +288,6 @@ def _getAndroidDeviceApi(cfg):
             AddSubstitution("%{clang-tidy}", lambda cfg: _getSuitableClangTidy(cfg))
         ],
     ),
-    Feature(name="apple-clang", when=_isAppleClang),
-    Feature(
-        name=lambda cfg: "apple-clang-{__clang_major__}".format(**compilerMacros(cfg)),
-        when=_isAppleClang,
-    ),
-    Feature(
-        name=lambda cfg: "apple-clang-{__clang_major__}.{__clang_minor__}".format(**compilerMacros(cfg)),
-        when=_isAppleClang,
-    ),
-    Feature(
-        name=lambda cfg: "apple-clang-{__clang_major__}.{__clang_minor__}.{__clang_patchlevel__}".format(**compilerMacros(cfg)),
-        when=_isAppleClang,
-    ),
-    Feature(name="clang", when=_isClang),
-    Feature(
-        name=lambda cfg: "clang-{__clang_major__}".format(**compilerMacros(cfg)),
-        when=_isClang,
-    ),
-    Feature(
-        name=lambda cfg: "clang-{__clang_major__}.{__clang_minor__}".format(**compilerMacros(cfg)),
-        when=_isClang,
-    ),
-    Feature(
-        name=lambda cfg: "clang-{__clang_major__}.{__clang_minor__}.{__clang_patchlevel__}".format(**compilerMacros(cfg)),
-        when=_isClang,
-    ),
-    # Note: Due to a GCC bug (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104760), we must disable deprecation warnings
-    #       on GCC or spurious diagnostics are issued.
-    #
-    # TODO:
-    # - Enable -Wplacement-new with GCC.
-    # - Enable -Wclass-memaccess with GCC.
-    Feature(
-        name="gcc",
-        when=_isGCC,
-        actions=[
-            AddCompileFlag("-D_LIBCPP_DISABLE_DEPRECATION_WARNINGS"),
-            AddCompileFlag("-Wno-placement-new"),
-            AddCompileFlag("-Wno-class-memaccess"),
-            AddFeature("GCC-ALWAYS_INLINE-FIXME"),
-        ],
-    ),
-    Feature(
-        name=lambda cfg: "gcc-{__GNUC__}".format(**compilerMacros(cfg)), when=_isGCC
-    ),
-    Feature(
-        name=lambda cfg: "gcc-{__GNUC__}.{__GNUC_MINOR__}".format(**compilerMacros(cfg)),
-        when=_isGCC,
-    ),
-    Feature(
-        name=lambda cfg: "gcc-{__GNUC__}.{__GNUC_MINOR__}.{__GNUC_PATCHLEVEL__}".format(**compilerMacros(cfg)),
-        when=_isGCC,
-    ),
-    Feature(name="msvc", when=_isMSVC),
-    Feature(name=lambda cfg: "msvc-{}".format(*_msvcVersion(cfg)), when=_isMSVC),
-    Feature(name=lambda cfg: "msvc-{}.{}".format(*_msvcVersion(cfg)), when=_isMSVC),
 ]
 
 # Deduce and add the test features that that are implied by the #defines in