Only pass implicit -MQ to preprocessor if needed

This is a bug fix of 76a9959f3d3e.

3 files changed, 36 insertions, 1 deletions

diff --git a/doc/NEWS.adoc b/doc/NEWS.adoc
index 10a827b4..ae195180 100644
--- a/doc/NEWS.adoc
+++ b/doc/NEWS.adoc
@@ -11,6 +11,11 @@ Bug fixes
 - Fixed a regression in 3.7.2 that could result in a warning message instead of
   an error in an edge case related to usage of “-Werror”.
 
+- An implicit `-MQ` is now passed to the preprocessor only if the object file
+  extension is non-standard. This should make it easier to use EDG-based
+  compilers (e.g. GHS) which don’t understand `-MQ`. (This is a bug fix of the
+  corresponding improvement implemented in ccache 3.4.)
+
 
 ccache 3.7.4
 ------------
diff --git a/src/ccache.c b/src/ccache.c
index 9c605934..b9f1e479 100644
--- a/src/ccache.c
+++ b/src/ccache.c
@@ -3522,7 +3522,7 @@ cc_process_args(struct args *args,
 
 		if (!dependency_target_specified
 		    && !dependency_implicit_target_specified
-		    && !str_eq(get_extension(output_dep), ".o")) {
+		    && !str_eq(get_extension(output_obj), ".o")) {
 			args_add(dep_args, "-MQ");
 			args_add(dep_args, output_obj);
 		}
diff --git a/unittest/test_argument_processing.c b/unittest/test_argument_processing.c
index ca48c2a5..b6c7476a 100644
--- a/unittest/test_argument_processing.c
+++ b/unittest/test_argument_processing.c
@@ -173,6 +173,36 @@ TEST(dependency_flags_that_take_an_argument_should_not_require_space_delimiter)
 	args_free(orig);
 }
 
+TEST(MQ_flag_should_not_be_added_for_standard_obj_extension)
+{
+	struct args *orig = args_init_from_string("cc -c -MD foo.c -o foo.o");
+	struct args *exp_cpp = args_init_from_string("cc -MD -MF foo.d");
+	struct args *exp_cc = args_init_from_string("cc -c");
+	struct args *act_cpp = NULL, *act_cc = NULL;
+	create_file("foo.c", "");
+
+	CHECK(cc_process_args(orig, &act_cpp, NULL, &act_cc));
+	CHECK_ARGS_EQ_FREE12(exp_cpp, act_cpp);
+	CHECK_ARGS_EQ_FREE12(exp_cc, act_cc);
+
+	args_free(orig);
+}
+
+TEST(MQ_flag_should_be_added_for_non_standard_obj_extension)
+{
+	struct args *orig = args_init_from_string("cc -c -MD foo.c -o foo.obj");
+	struct args *exp_cpp = args_init_from_string("cc -MD -MF foo.d -MQ foo.obj");
+	struct args *exp_cc = args_init_from_string("cc -c");
+	struct args *act_cpp = NULL, *act_cc = NULL;
+	create_file("foo.c", "");
+
+	CHECK(cc_process_args(orig, &act_cpp, NULL, &act_cc));
+	CHECK_ARGS_EQ_FREE12(exp_cpp, act_cpp);
+	CHECK_ARGS_EQ_FREE12(exp_cc, act_cc);
+
+	args_free(orig);
+}
+
 TEST(sysroot_should_be_rewritten_if_basedir_is_used)
 {
 	extern char *current_working_dir;