tcc: Refactor "compute default outfile name" into libtcc function

Since for upcoming -MD support default _compile_ output file be needed
even when preprocesssing (tcc -E), let's move this code out of one
particular condition block into a common function, so that we could use
it in deps generation code too.

v2:

- As suggested by grischka, moved into libtcc function instead of always
  computing near start of main()
- There is a FIXME about how to return result - I don't want to bother
  callers with allocating temp buffers, not I think it will be a good
  idea to hook default_target to TCCState. Clearly, I'm to used to
  things like std::string and python's str...

2 files changed, 32 insertions, 25 deletions

diff --git a/libtcc.c b/libtcc.c
index 9cc1b6f..1c963b5 100644
--- a/libtcc.c
+++ b/libtcc.c
@@ -1557,3 +1557,31 @@ PUB_FUNC void set_num_callers(int n)
     num_callers = n;
 #endif
 }
+
+
+LIBTCCAPI const char *tcc_default_target(TCCState *s)
+{
+    /* FIXME will break in multithreaded case */
+    static char outfile_default[1024];
+
+    char *ext;
+    const char *name =
+        strcmp(s->input_files[0], "-") == 0 ? "a"
+                                            : tcc_basename(s->input_files[0]);
+    pstrcpy(outfile_default, sizeof(outfile_default), name);
+    ext = tcc_fileextension(outfile_default);
+#ifdef TCC_TARGET_PE
+    if (s->output_type == TCC_OUTPUT_DLL)
+        strcpy(ext, ".dll");
+    else
+    if (s->output_type == TCC_OUTPUT_EXE)
+        strcpy(ext, ".exe");
+    else
+#endif
+    if (s->output_type == TCC_OUTPUT_OBJ && !s->reloc_output && *ext)
+        strcpy(ext, ".o");
+    else
+        pstrcpy(outfile_default, sizeof(outfile_default), "a.out");
+
+    return outfile_default;
+}
diff --git a/tcc.c b/tcc.c
index f973972..705f5e2 100644
--- a/tcc.c
+++ b/tcc.c
@@ -393,7 +393,6 @@ int main(int argc, char **argv)
     int i;
     TCCState *s;
     int nb_objfiles, ret, optind;
-    char objfilename[1024];
     int64_t start_time = 0;
 
     s = tcc_new();
@@ -446,28 +445,6 @@ int main(int argc, char **argv)
             if (!s->outfile)
                 error("could not open '%s'", outfile);
         }
-    } else if (output_type != TCC_OUTPUT_MEMORY) {
-        if (!outfile) {
-            /* compute default outfile name */
-            char *ext;
-            const char *name = 
-                strcmp(files[0], "-") == 0 ? "a" : tcc_basename(files[0]);
-            pstrcpy(objfilename, sizeof(objfilename), name);
-            ext = tcc_fileextension(objfilename);
-#ifdef TCC_TARGET_PE
-            if (output_type == TCC_OUTPUT_DLL)
-                strcpy(ext, ".dll");
-            else
-            if (output_type == TCC_OUTPUT_EXE)
-                strcpy(ext, ".exe");
-            else
-#endif
-            if (output_type == TCC_OUTPUT_OBJ && !reloc_output && *ext)
-                strcpy(ext, ".o");
-            else
-                pstrcpy(objfilename, sizeof(objfilename), "a.out");
-            outfile = objfilename;
-        }
     }
 
     if (do_bench) {
@@ -507,8 +484,10 @@ int main(int argc, char **argv)
                 fclose(s->outfile);
         } else if (s->output_type == TCC_OUTPUT_MEMORY)
             ret = tcc_run(s, argc - optind, argv + optind);
-        else
-            ret = tcc_output_file(s, outfile) ? 1 : 0;
+        else {
+            ret = tcc_output_file(s, outfile ? outfile : tcc_default_target(s));
+            ret = ret ? 1 : 0;
+        }
     }
 
     tcc_delete(s);