Disable direct mode for "-Wp," with multiple preprocessor options

This fixes a regression in ccache 3.2.8/3.3.1 (commit 026ba6b9): ccache
could get confused when using the compiler option -Wp, to pass multiple
options to the preprocessor, resulting in missing dependency files from
direct mode cache hits.

Closes #133.

2 files changed, 19 insertions, 3 deletions

diff --git a/NEWS.txt b/NEWS.txt
index 57451a49..00b4c202 100644
--- a/NEWS.txt
+++ b/NEWS.txt
@@ -1,6 +1,16 @@
 ccache news
 ===========
 
+Unreleased 3.2.9
+----------------
+
+Bug fixes
+~~~~~~~~~
+
+- Fixed a regression in ccache 3.2.8: ccache could get confused when using the
+  compiler option `-Wp,` to pass multiple options to the preprocessor,
+  resulting in missing dependency files from direct mode cache hits.
+
 
 ccache 3.2.8
 ------------
diff --git a/ccache.c b/ccache.c
index 5635cc15..ddbc822e 100644
--- a/ccache.c
+++ b/ccache.c
@@ -2249,9 +2249,15 @@ cc_process_args(struct args *args, struct args **preprocessor_args,
 				output_dep = make_relative_path(x_strdup(argv[i] + 9));
 				args_add(dep_args, argv[i]);
 				continue;
-			} else if (str_startswith(argv[i], "-Wp,-M")) {
-				/* -MF, -MP, -MQ, -MT, etc. TODO: Make argument to MF/MQ/MT
-				 * relative. */
+			} else if (str_eq(argv[i], "-Wp,-MP")
+			           || (strlen(argv[i]) > 8
+			               && str_startswith(argv[i], "-Wp,-M")
+			               && argv[i][7] == ','
+			               && (argv[i][6] == 'F'
+			                   || argv[i][6] == 'Q'
+			                   || argv[i][6] == 'T')
+			               && !strchr(argv[i] + 8, ','))) {
+				/* TODO: Make argument to MF/MQ/MT relative. */
 				args_add(dep_args, argv[i]);
 				continue;
 			} else if (conf->direct_mode) {