diff --git a/libtcc.c b/libtcc.c
index 31029616..c2ec5b61 100644
--- a/libtcc.c
+++ b/libtcc.c
@@ -1867,9 +1867,10 @@ reparse:
 #endif
         case TCC_OPTION_g:
             s->do_debug = 1;
-	    s->dwarf = DWARF_VERSION;
-	    if (strstart("dwarf-", &optarg))
-                s->dwarf = atoi(optarg);
+            s->dwarf = DWARF_VERSION;
+
+            if (strstart("dwarf", &optarg))
+                s->dwarf = (*optarg) ? (0 - atoi(optarg)) : DEFAULT_DWARF_VERSION;
             break;
         case TCC_OPTION_c:
             x = TCC_OUTPUT_OBJ;
diff --git a/tcc.h b/tcc.h
index 9e0388cd..0c7208f7 100644
--- a/tcc.h
+++ b/tcc.h
@@ -1815,10 +1815,18 @@ ST_FUNC void tcc_tcov_reset_ind(TCCState *s1);
 #define dwarf_str_section       s1->dwarf_str_section
 #define dwarf_line_str_section  s1->dwarf_line_str_section
 
+/* default dwarf version for "-g". use 0 to emit stab debug infos */
 #ifndef DWARF_VERSION
 # define DWARF_VERSION 0
 #endif
 
+/* default dwarf version for "-gdwarf" */
+#ifdef TCC_TARGET_MACHO
+# define DEFAULT_DWARF_VERSION 2
+#else
+# define DEFAULT_DWARF_VERSION 5
+#endif
+
 #if defined TCC_TARGET_PE
 # define R_DATA_32DW 'Z' /* fake code to avoid DLL relocs */
 #elif defined TCC_TARGET_X86_64