Fix debug Windows builds in MSVC 2015

We were sometimes passing invalid input to isalnum(). On the debug version of MSVCRT this would result in an assert.

diff --git a/mono/mini/genmdesc.c b/mono/mini/genmdesc.c
index b996f8f83b55a07a401a31409d4f5c437228d43c..7118e19c8cec06cd9fb7588d5e7c89f2e9564706 100644 (file)
--- a/mono/mini/genmdesc.c
+++ b/mono/mini/genmdesc.c
@@ -54,6 +54,14 @@ static GHashTable *template_table;
 
 #define eat_whitespace(s) while (*(s) && isspace (*(s))) s++;
 
+// Per spec isalnum() expects input in the range 0-255
+// and can misbehave if you pass in a signed char.
+static int
+isalnum_char(char c)
+{
+       return isalnum ((unsigned char)c);
+}
+
 static int
 load_file (const char *name) {
        FILE *f;
@@ -163,7 +171,7 @@ load_file (const char *name) {
                                OpDesc *tdesc;
                                p += 9;
                                tname = p;
-                               while (*p && isalnum (*p)) ++p;
+                               while (*p && isalnum_char (*p)) ++p;
                                *p++ = 0;
                                tdesc = (OpDesc *)g_hash_table_lookup (template_table, tname);
                                if (!tdesc)
@@ -181,7 +189,7 @@ load_file (const char *name) {
                                        g_error ("Duplicated name tag in template %s at '%s' at line %d in %s\n", desc->name, p, line, name);
                                p += 5;
                                tname = p;
-                               while (*p && isalnum (*p)) ++p;
+                               while (*p && isalnum_char (*p)) ++p;
                                *p++ = 0;
                                if (g_hash_table_lookup (template_table, tname))
                                        g_error ("Duplicated template %s at line %d in %s\n", tname, line, name);
@@ -220,7 +228,7 @@ init_table (void) {
 
 static void
 output_char (FILE *f, char c) {
-       if (isalnum (c))
+       if (isalnum_char (c))
                fprintf (f, "%c", c);
        else
                fprintf (f, "\\x%x\" \"", (guint8)c);