Implement -dM preprocessor option as in gcc

There was already support for -dD option but in contrast -dM dumps only `#define` directives w/o actual preprocessor output.

The original -dD output differs from gcc output by additional comment in front of `#define`s so this quirk is left for -dM as well.

4 files changed, 14 insertions, 8 deletions

diff --git a/libtcc.c b/libtcc.c
index 8fd8183..7b232a2 100644
--- a/libtcc.c
+++ b/libtcc.c
@@ -1225,6 +1225,8 @@ LIBTCCAPI void tcc_delete(TCCState *s1)
     /* close a preprocessor output */
     if (s1->ppfp && s1->ppfp != stdout)
         fclose(s1->ppfp);
+    if (s1->dffp && s1->dffp != s1->ppfp)
+        fclose(s1->dffp);
 
     /* free all sections */
     for(i = 1; i < s1->nb_sections; i++)
@@ -2175,8 +2177,8 @@ PUB_FUNC int tcc_parse_args(TCCState *s, int argc, char **argv)
             s->output_type = TCC_OUTPUT_OBJ;
             break;
         case TCC_OPTION_d:
-            if (*optarg == 'D')
-                s->dflag = 1;
+            if (*optarg == 'D' || *optarg == 'M')
+                s->dflag = *optarg;
             else {
                 if (s->warn_unsupported)
                     goto unsupported_option;
diff --git a/tcc.c b/tcc.c
index 9daf6e6..95e1a15 100644
--- a/tcc.c
+++ b/tcc.c
@@ -301,6 +301,9 @@ int main(int argc, char **argv)
             if (!s->ppfp)
                 tcc_error("could not write '%s'", s->outfile);
         }
+        s->dffp = s->ppfp;
+        if (s->dflag == 'M')
+            s->ppfp = NULL;
     }
 
     tcc_set_output_type(s, s->output_type);
diff --git a/tcc.h b/tcc.h
index 2e1e32f..f5d283e 100644
--- a/tcc.h
+++ b/tcc.h
@@ -712,7 +712,8 @@ struct TCCState {
 	LINE_MACRO_OUTPUT_FORMAT_NONE,
 	LINE_MACRO_OUTPUT_FORMAT_STD
     } Pflag; /* -P switch */
-    int dflag; /* -dX value */
+    char dflag; /* -dX value */
+    FILE *dffp;
 
     /* for -MD/-MF: collected dependencies for this compilation */
     char **target_deps;
diff --git a/tccpp.c b/tccpp.c
index 70a2258..80c7dd8 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -1092,7 +1092,7 @@ static void pp_line(TCCState *s1, BufferedFile *f, int level)
 
 static void tok_print(const char *msg, const int *str)
 {
-    FILE *pr = tcc_state->ppfp;
+    FILE *pr = tcc_state->dffp;
     int t;
     CValue cval;
 
@@ -1108,13 +1108,13 @@ static void tok_print(const char *msg, const int *str)
 
 static int define_print_prepared(Sym *s)
 {
-    if (!s || !tcc_state->ppfp || tcc_state->dflag == 0)
+    if (!s || !tcc_state->dffp || tcc_state->dflag == 0)
         return 0;
 
     if (s->v < TOK_IDENT || s->v >= tok_ident)
         return 0;
 
-    if (file) {
+    if (file && tcc_state->dflag == 'D') {
         file->line_num--;
         pp_line(tcc_state, file, 0);
         file->line_ref = ++file->line_num;
@@ -1124,7 +1124,7 @@ static int define_print_prepared(Sym *s)
 
 static void define_print(int v)
 {
-    FILE *pr = tcc_state->ppfp;
+    FILE *pr = tcc_state->dffp;
     Sym *s, *a;
 
     s = define_find(v);
@@ -1149,7 +1149,7 @@ static void define_print(int v)
 
 static void undef_print(int v)
 {
-    FILE *pr = tcc_state->ppfp;
+    FILE *pr = tcc_state->dffp;
     Sym *s;
 
     s = define_find(v);