Use CPPFLAGS for pre-processor compiler checks

Also don't add CFLAGS twice for links() checks

Includes a test for this.

mesonbuild/compilers.py

@@ -953,12 +953,14 @@ class CCompiler(Compiler):
         # Read c_args/cpp_args/etc from the cross-info file (if needed)
         args += self.get_cross_extra_flags(env, compile=(mode != 'preprocess'),
                                            link=(mode == 'link'))
-        # Add CFLAGS/CXXFLAGS/OBJCFLAGS/OBJCXXFLAGS from the env
-        # We assume that the user has ensured these are compiler-specific
-        args += env.coredata.external_args[self.language]
-        # Add LDFLAGS from the env. We assume that the user has ensured these
-        # are compiler-specific
-        if mode == 'link':
+        if mode == 'preprocess':
+            # Add CPPFLAGS from the env.
+            args += env.coredata.external_preprocess_args[self.language]
+        elif mode == 'compile':
+            # Add CFLAGS/CXXFLAGS/OBJCFLAGS/OBJCXXFLAGS from the env
+            args += env.coredata.external_args[self.language]
+        elif mode == 'link':
+            # Add LDFLAGS from the env
             args += env.coredata.external_link_args[self.language]
         args += self.get_compiler_check_args()
         # extra_args must override all other arguments, so we add them last

mesonbuild/coredata.py

@@ -148,10 +148,11 @@ class CoreData:
         self.user_options = {}
         self.compiler_options = {}
         self.base_options = {}
-        # These two, external_*args, are set via env vars CFLAGS, LDFLAGS, etc
+        # These external_*args, are set via env vars CFLAGS, LDFLAGS, etc
         # but only when not cross-compiling.
-        self.external_args = {}
-        self.external_link_args = {}
+        self.external_preprocess_args = {} # CPPFLAGS only
+        self.external_args = {} # CPPFLAGS + CFLAGS
+        self.external_link_args = {} # CFLAGS + LDFLAGS (with MSVC: only LDFLAGS)
         if options.cross_file is not None:
             self.cross_file = os.path.join(os.getcwd(), options.cross_file)
         else:

mesonbuild/environment.py

@@ -770,7 +770,7 @@ def get_args_from_envvars(compiler):
         compiler_is_linker = (compiler.get_exelist() == compiler.get_linker_exelist())
 
     if lang not in ('c', 'cpp', 'objc', 'objcpp', 'fortran', 'd'):
-        return [], []
+        return [], [], []
 
     # Compile flags
     cflags_mapping = {'c': 'CFLAGS',
@@ -794,7 +794,7 @@ def get_args_from_envvars(compiler):
         # this when the linker is stand-alone such as with MSVC C/C++, etc.
         link_flags = compile_flags + link_flags
 
-    # Pre-processof rlags (not for fortran)
+    # Pre-processor flags (not for fortran or D)
     preproc_flags = ''
     if lang in ('c', 'cpp', 'objc', 'objcpp'):
         preproc_flags = os.environ.get('CPPFLAGS', '')
@@ -802,7 +802,7 @@ def get_args_from_envvars(compiler):
     preproc_flags = shlex.split(preproc_flags)
     compile_flags += preproc_flags
 
-    return compile_flags, link_flags
+    return preproc_flags, compile_flags, link_flags
 
 class CrossBuildInfo:
     def __init__(self, filename):

mesonbuild/interpreter.py

@@ -1787,9 +1787,10 @@ class Interpreter(InterpreterBase):
                         raise
             mlog.log('Native %s compiler: ' % lang, mlog.bold(' '.join(comp.get_exelist())), ' (%s %s)' % (comp.id, comp.version), sep='')
             if not comp.get_language() in self.coredata.external_args:
-                (ext_compile_args, ext_link_args) = environment.get_args_from_envvars(comp)
-                self.coredata.external_args[comp.get_language()] = ext_compile_args
-                self.coredata.external_link_args[comp.get_language()] = ext_link_args
+                (preproc_args, compile_args, link_args) = environment.get_args_from_envvars(comp)
+                self.coredata.external_preprocess_args[comp.get_language()] = preproc_args
+                self.coredata.external_args[comp.get_language()] = compile_args
+                self.coredata.external_link_args[comp.get_language()] = link_args
             self.build.add_compiler(comp)
             if need_cross_compiler:
                 mlog.log('Cross %s compiler: ' % lang, mlog.bold(' '.join(cross_comp.get_exelist())), ' (%s %s)' % (cross_comp.id, cross_comp.version), sep='')

run_unittests.py

@@ -947,6 +947,21 @@ class AllPlatformTests(BasePlatformTests):
             m = re.search('build c-asm.*: c_LINKER', contents)
         self.assertIsNotNone(m, msg=contents)
 
+    def test_preprocessor_checks_CPPFLAGS(self):
+        '''
+        Test that preprocessor compiler checks read CPPFLAGS but not CFLAGS
+        '''
+        testdir = os.path.join(self.common_test_dir, '140 get define')
+        define = 'MESON_TEST_DEFINE_VALUE'
+        # NOTE: this list can't have \n, ' or "
+        # \n is never substituted by the GNU pre-processor via a -D define
+        # ' and " confuse shlex.split() even when they are escaped
+        # % and # confuse the MSVC preprocessor
+        value = 'spaces and fun!@$^&*()-=_+{}[]:;<>?,./~`'
+        os.environ['CPPFLAGS'] = '-D{}="{}"'.format(define, value)
+        os.environ['CFLAGS'] = '-DMESON_FAIL_VALUE=cflags-read'.format(define)
+        self.init(testdir, ['-D{}={}'.format(define, value)])
+
 
 class WindowsTests(BasePlatformTests):
     '''

test cases/common/140 get define/meson.build

@@ -16,4 +16,13 @@ foreach lang : ['c', 'cpp']
   else
     error('Please report a bug and help us improve support for this platform')
   endif
+
+  # Check that an undefined value is empty.
+  have = cc.get_define('MESON_FAIL_VALUE')
+  assert(have == '', 'MESON_FAIL_VALUE value is "@0@" instead of ""'.format(have))
+
+  # This is used in the test_preprocessor_checks_CPPFLAGS() unit test.
+  have = cc.get_define('MESON_TEST_DEFINE_VALUE')
+  expect = get_option('MESON_TEST_DEFINE_VALUE')
+  assert(have == expect, 'MESON_TEST_DEFINE_VALUE value is "@0@" instead of "@1@"'.format(have, expect))
 endforeach

test cases/common/140 get define/meson_options.txt

@@ -0,0 +1 @@
+option('MESON_TEST_DEFINE_VALUE', type : 'string', default : '')