From de4de65f9725039f1d4c60bce61740d481cfe07c Mon Sep 17 00:00:00 2001
From: Jonathan Schleifer <js@nil.im>
Date: Thu, 11 Apr 2024 01:44:58 +0200
Subject: [PATCH] Prefer Clang over GCC for Objective-C(++)

GCC only has very limited support for Objective-C and doesn't support
any of the modern features, so whenever Clang is available, it should be
used instead. Essentially, the only reason to ever use GCC for
Objective-C is that Clang simply does not support the target system.

This also sets CC=clang for "test cases/cmake/24 mixing
languages/test.json" as openSUSE's GCC defaults to no PIE while
openSUSE's Clang defaults to PIE, which makes the test fail if
OBJC=clang and CC=gcc.

Co-authored-by: Tristan Partin <tristan@partin.io>
---
 .github/workflows/cygwin.yml                   | 1 +
 .github/workflows/msys2.yml                    | 1 +
 mesonbuild/compilers/detect.py                 | 9 ++++-----
 test cases/cmake/24 mixing languages/test.json | 5 +++++
 4 files changed, 11 insertions(+), 5 deletions(-)
 create mode 100644 test cases/cmake/24 mixing languages/test.json

diff --git a/.github/workflows/cygwin.yml b/.github/workflows/cygwin.yml
index c6f3dc416687..8dfedd3c67ba 100644
--- a/.github/workflows/cygwin.yml
+++ b/.github/workflows/cygwin.yml
@@ -55,6 +55,7 @@ jobs:
         with:
           platform: ${{ matrix.ARCH }}
           packages: |
+            clang
             cmake
             gcc-fortran
             gcc-objc++
diff --git a/.github/workflows/msys2.yml b/.github/workflows/msys2.yml
index fe28a67edbad..cf92f2bc6e80 100644
--- a/.github/workflows/msys2.yml
+++ b/.github/workflows/msys2.yml
@@ -74,6 +74,7 @@ jobs:
             lcov
             wget
             unzip
+            mingw-w64-${{ matrix.MSYS2_ARCH }}-clang
             mingw-w64-${{ matrix.MSYS2_ARCH }}-cmake
             mingw-w64-${{ matrix.MSYS2_ARCH }}-glib2
             mingw-w64-${{ matrix.MSYS2_ARCH }}-libxml2
diff --git a/mesonbuild/compilers/detect.py b/mesonbuild/compilers/detect.py
index aed03391889d..53d40def42d7 100644
--- a/mesonbuild/compilers/detect.py
+++ b/mesonbuild/compilers/detect.py
@@ -46,9 +46,8 @@
     # There is currently no pgc++ for Windows, only for  Mac and Linux.
     defaults['cpp'] = ['icl', 'cl', 'c++', 'g++', 'clang++', 'clang-cl']
     defaults['fortran'] = ['ifort', 'gfortran', 'flang', 'pgfortran', 'g95']
-    # Clang and clang++ are valid, but currently unsupported.
-    defaults['objc'] = ['cc', 'gcc']
-    defaults['objcpp'] = ['c++', 'g++']
+    defaults['objc'] = ['clang-cl', 'gcc']
+    defaults['objcpp'] = ['clang-cl', 'g++']
     defaults['cs'] = ['csc', 'mcs']
 else:
     if platform.machine().lower() == 'e2k':
@@ -59,8 +58,8 @@
     else:
         defaults['c'] = ['cc', 'gcc', 'clang', 'nvc', 'pgcc', 'icc', 'icx']
         defaults['cpp'] = ['c++', 'g++', 'clang++', 'nvc++', 'pgc++', 'icpc', 'icpx']
-        defaults['objc'] = ['cc', 'gcc', 'clang']
-        defaults['objcpp'] = ['c++', 'g++', 'clang++']
+        defaults['objc'] = ['clang', 'gcc']
+        defaults['objcpp'] = ['clang++', 'g++']
     defaults['fortran'] = ['gfortran', 'flang', 'nvfortran', 'pgfortran', 'ifort', 'ifx', 'g95']
     defaults['cs'] = ['mcs', 'csc']
 defaults['d'] = ['ldc2', 'ldc', 'gdc', 'dmd']
diff --git a/test cases/cmake/24 mixing languages/test.json b/test cases/cmake/24 mixing languages/test.json
new file mode 100644
index 000000000000..501fcfe8c113
--- /dev/null
+++ b/test cases/cmake/24 mixing languages/test.json	
@@ -0,0 +1,5 @@
+{
+  "env": {
+    "CC": "clang"
+  }
+}