Split environment variable and command line cflags

They are supposed to have different behavior. The environment variables
apply to both the compiler and linker when the compiler acts as a
linker, but the command line ones do not.

Fixes #8345

1 files changed, 22 insertions, 0 deletions

diff --git a/run_unittests.py b/run_unittests.py
index fd75c8c..1eba4df 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -5634,6 +5634,28 @@ class AllPlatformTests(BasePlatformTests):
                 matches += 1
         self.assertEqual(matches, 1)
 
+    def test_env_flags_to_linker(self) -> None:
+        # Compilers that act as drivers should add their compiler flags to the
+        # linker, those that do not shouldn't
+        with mock.patch.dict(os.environ, {'CFLAGS': '-DCFLAG', 'LDFLAGS': '-flto'}):
+            env = get_fake_env()
+
+            # Get the compiler so we know which compiler class to mock.
+            cc = env.detect_compiler_for('c', MachineChoice.HOST)
+            cc_type = type(cc)
+
+            # Test a compiler that acts as a linker
+            with mock.patch.object(cc_type, 'INVOKES_LINKER', True):
+                cc = env.detect_compiler_for('c', MachineChoice.HOST)
+                link_args = env.coredata.get_external_link_args(cc.for_machine, cc.language)
+                self.assertEqual(sorted(link_args), sorted(['-DCFLAG', '-flto']))
+
+            # And one that doesn't
+            with mock.patch.object(cc_type, 'INVOKES_LINKER', False):
+                cc = env.detect_compiler_for('c', MachineChoice.HOST)
+                link_args = env.coredata.get_external_link_args(cc.for_machine, cc.language)
+                self.assertEqual(sorted(link_args), sorted(['-flto']))
+
 class FailureTests(BasePlatformTests):
     '''
     Tests that test failure conditions. Build files here should be dynamically