cross: Add compiler cross_args after normal args

This way they override all other arguments. This matches the order of
link arguments too.

Note that this means -I flags will come in afterwards and not override
anything else, but this is correct since that's how toolchain paths
work normally too -- they are searched last.

Closes https://github.com/mesonbuild/meson/issues/3089

mesonbuild/backend/ninjabackend.py

@@ -1660,9 +1660,9 @@ rule FORTRAN_DEP_HACK
         if mesonlib.is_windows():
             command_template = ' command = {executable} @$out.rsp\n' \
                                ' rspfile = $out.rsp\n' \
-                               ' rspfile_content = {cross_args} $ARGS {output_args} {compile_only_args} $in\n'
+                               ' rspfile_content =  $ARGS{cross_args} {output_args} {compile_only_args} $in\n'
         else:
-            command_template = ' command = {executable} {cross_args} $ARGS {output_args} {compile_only_args} $in\n'
+            command_template = ' command = {executable} $ARGS {cross_args} {output_args} {compile_only_args} $in\n'
         command = command_template.format(
             executable=' '.join([ninja_quote(i) for i in compiler.get_exelist()]),
             cross_args=' '.join(self.get_cross_info_lang_args(compiler.language, is_cross)),
@@ -1721,10 +1721,10 @@ rule FORTRAN_DEP_HACK
         if mesonlib.is_windows():
             command_template = ''' command = {executable} @$out.rsp
  rspfile = $out.rsp
- rspfile_content = {cross_args} $ARGS {dep_args} {output_args} {compile_only_args} $in
+ rspfile_content = $ARGS {cross_args} {dep_args} {output_args} {compile_only_args} $in
 '''
         else:
-            command_template = ' command = {executable} {cross_args} $ARGS {dep_args} {output_args} {compile_only_args} $in\n'
+            command_template = ' command = {executable} $ARGS {cross_args} {dep_args} {output_args} {compile_only_args} $in\n'
         command = command_template.format(
             executable=' '.join([ninja_quote(i) for i in compiler.get_exelist()]),
             cross_args=' '.join(cross_args),
@@ -1769,7 +1769,7 @@ rule FORTRAN_DEP_HACK
             output = ''
         else:
             output = ' '.join(compiler.get_output_args('$out'))
-        command = " command = {executable} {cross_args} $ARGS {dep_args} {output_args} {compile_only_args} $in\n".format(
+        command = " command = {executable} $ARGS {cross_args} {dep_args} {output_args} {compile_only_args} $in\n".format(
             executable=' '.join(compiler.get_exelist()),
             cross_args=' '.join(cross_args),
             dep_args=' '.join(quoted_depargs),

run_unittests.py

@@ -482,6 +482,7 @@ class BasePlatformTests(unittest.TestCase):
         self.backend = getattr(Backend, os.environ.get('MESON_UNIT_TEST_BACKEND', 'ninja'))
         self.meson_mainfile = os.path.join(src_root, 'meson.py')
         self.meson_args = ['--backend=' + self.backend.name]
+        self.meson_cross_file = None
         self.meson_command = meson_command + self.meson_args
         self.mconf_command = meson_command + ['configure']
         self.mintro_command = meson_command + ['introspect']
@@ -567,6 +568,8 @@ class BasePlatformTests(unittest.TestCase):
         if default_args:
             args += ['--prefix', self.prefix,
                      '--libdir', self.libdir]
+            if self.meson_cross_file:
+                args += ['--cross-file', self.meson_cross_file]
         self.privatedir = os.path.join(self.builddir, 'meson-private')
         if inprocess:
             try:
@@ -2814,7 +2817,8 @@ cpu = 'armv7' # Not sure if correct.
 endian = 'little'
 ''' % os.path.join(testdir, 'some_cross_tool.py'))
         crossfile.flush()
-        self.init(testdir, ['--cross-file=' + crossfile.name])
+        self.meson_cross_file = crossfile.name
+        self.init(testdir)
 
     def test_reconfigure(self):
         testdir = os.path.join(self.unit_test_dir, '13 reconfigure')
@@ -2920,7 +2924,7 @@ class LinuxArmCrossCompileTests(BasePlatformTests):
     def setUp(self):
         super().setUp()
         src_root = os.path.dirname(__file__)
-        self.meson_command += ['--cross=' + os.path.join(src_root, 'cross', 'ubuntu-armhf.txt')]
+        self.meson_cross_file = os.path.join(src_root, 'cross', 'ubuntu-armhf.txt')
 
     def test_cflags_cross_environment_pollution(self):
         '''
@@ -2934,6 +2938,21 @@ class LinuxArmCrossCompileTests(BasePlatformTests):
         compdb = self.get_compdb()
         self.assertNotIn('-DBUILD_ENVIRONMENT_ONLY', compdb[0]['command'])
 
+    def test_cross_file_overrides_always_args(self):
+        '''
+        Test that $lang_args in cross files always override get_always_args().
+        Needed for overriding the default -D_FILE_OFFSET_BITS=64 on some
+        architectures such as some Android versions and Raspbian.
+        https://github.com/mesonbuild/meson/issues/3049
+        https://github.com/mesonbuild/meson/issues/3089
+        '''
+        testdir = os.path.join(self.unit_test_dir, '29 cross file overrides always args')
+        self.meson_cross_file = os.path.join(self.unit_test_dir, 'ubuntu-armhf-overrides.txt')
+        self.init(testdir)
+        compdb = self.get_compdb()
+        self.assertRegex(compdb[0]['command'], '-D_FILE_OFFSET_BITS=64.*-U_FILE_OFFSET_BITS')
+        self.build()
+
 
 class RewriterTests(unittest.TestCase):
 

test cases/unit/29 cross file overrides always args/meson.build

@@ -0,0 +1,3 @@
+project('cross compile args override always args', 'c')
+
+executable('no-file-offset-bits', 'test.c')

test cases/unit/29 cross file overrides always args/test.c

@@ -0,0 +1,8 @@
+#ifdef _FILE_OFFSET_BITS
+  #error "_FILE_OFFSET_BITS should not be set"
+#endif
+
+int main(int argc, char *argv[])
+{
+  return 0;
+}

test cases/unit/29 cross file overrides always args/ubuntu-armhf-overrides.txt

@@ -0,0 +1,19 @@
+[binaries]
+# we could set exe_wrapper = qemu-arm-static but to test the case
+# when cross compiled binaries can't be run we don't do that
+c = '/usr/bin/arm-linux-gnueabihf-gcc'
+cpp = '/usr/bin/arm-linux-gnueabihf-g++'
+rust = ['rustc', '--target', 'arm-unknown-linux-gnueabihf', '-C', 'linker=/usr/bin/arm-linux-gnueabihf-gcc-7']
+ar = '/usr/arm-linux-gnueabihf/bin/ar'
+strip = '/usr/arm-linux-gnueabihf/bin/strip'
+pkgconfig = '/usr/bin/arm-linux-gnueabihf-pkg-config'
+
+[properties]
+root = '/usr/arm-linux-gnueabihf'
+c_args = ['-U_FILE_OFFSET_BITS']
+
+[host_machine]
+system = 'linux'
+cpu_family = 'arm'
+cpu = 'armv7' # Not sure if correct.
+endian = 'little'