From a715d7143d9d17da17e67fec6af1c01409a71a31 Mon Sep 17 00:00:00 2001
From: Thomas Preud'homme <robotux@celest.fr>
Date: Tue, 8 Apr 2014 22:19:48 +0800
Subject: Prevent ## to appear at start or end of macro

---
 tccpp.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

(limited to 'tccpp.c')

diff --git a/tccpp.c b/tccpp.c
index 7144ee4..c8beec5 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -1213,9 +1213,9 @@ static void tok_print(int *str)
 ST_FUNC void parse_define(void)
 {
     Sym *s, *first, **ps;
-    int v, t, varg, is_vaargs, spc;
+    int v, t, varg, is_vaargs, spc, ptok, macro_list_start;
     TokenString str;
-    
+
     v = tok;
     if (v < TOK_IDENT)
         tcc_error("invalid macro name '%s'", get_tok_str(tok, &tokc));
@@ -1254,8 +1254,13 @@ ST_FUNC void parse_define(void)
     tok_str_new(&str);
     spc = 2;
     /* EOF testing necessary for '-D' handling */
+    ptok = 0;
+    macro_list_start = 1;
     while (tok != TOK_LINEFEED && tok != TOK_EOF) {
-        /* remove spaces around ## and after '#' */        
+        if (!macro_list_start && spc == 2 && tok == TOK_TWOSHARPS)
+            tcc_error("'##' invalid at start of macro");
+        ptok = tok;
+        /* remove spaces around ## and after '#' */
         if (TOK_TWOSHARPS == tok) {
             if (1 == spc)
                 --str.len;
@@ -1268,7 +1273,10 @@ ST_FUNC void parse_define(void)
         tok_str_add2(&str, tok, &tokc);
     skip:
         next_nomacro_spc();
+        macro_list_start = 0;
     }
+    if (ptok == TOK_TWOSHARPS)
+        tcc_error("'##' invalid at end of macro");
     if (spc == 1)
         --str.len; /* remove trailing space */
     tok_str_add(&str, 0);
-- 
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