[Emacs-diffs] emacs-25 6e3adf8: Fix crash in syntax.c after GC

[Paul Eggert]

branch: emacs-25
commit 6e3adf8a4a796cea4328a528da48fc972b3feed6
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>

    Fix crash in syntax.c after GC
    
    Problem reported by Vincent Belaïche (Bug#23704).
    * src/syntax.c (skip_chars): Recompute pointers into the
    buffer after every call to update_syntax_table_forward,
    as it can GC.
---
 src/syntax.c |   59 ++++++++++++++++++++++++----------------------------------
 1 file changed, 24 insertions(+), 35 deletions(-)

diff --git a/src/syntax.c b/src/syntax.c
index 16b7fab..6f53684 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -2171,63 +2171,51 @@ skip_syntaxes (bool forwardp, Lisp_Object string, 
Lisp_Object lim)
     ptrdiff_t start_point = PT;
     ptrdiff_t pos = PT;
     ptrdiff_t pos_byte = PT_BYTE;
-    unsigned char *p = PT_ADDR, *endp, *stop;
-
-    if (forwardp)
-      {
-       endp = (XINT (lim) == GPT) ? GPT_ADDR : CHAR_POS_ADDR (XINT (lim));
-       stop = (pos < GPT && GPT < XINT (lim)) ? GPT_ADDR : endp;
-      }
-    else
-      {
-       endp = CHAR_POS_ADDR (XINT (lim));
-       stop = (pos >= GPT && GPT > XINT (lim)) ? GAP_END_ADDR : endp;
-      }
+    unsigned char *p, *endp, *stop;
 
     immediate_quit = 1;
     SETUP_SYNTAX_TABLE (pos, forwardp ? 1 : -1);
+
     if (forwardp)
       {
-       if (multibyte)
+       while (true)
          {
-           while (1)
+           p = BYTE_POS_ADDR (pos_byte);
+           endp = XINT (lim) == GPT ? GPT_ADDR : CHAR_POS_ADDR (XINT (lim));
+           stop = pos < GPT && GPT < XINT (lim) ? GPT_ADDR : endp;
+
+           do
              {
                int nbytes;
 
                if (p >= stop)
                  {
                    if (p >= endp)
-                     break;
+                     goto done;
                    p = GAP_END_ADDR;
                    stop = endp;
                  }
-               c = STRING_CHAR_AND_LENGTH (p, nbytes);
+               if (multibyte)
+                 c = STRING_CHAR_AND_LENGTH (p, nbytes);
+               else
+                 c = *p, nbytes = 1;
                if (! fastmap[SYNTAX (c)])
-                 break;
+                 goto done;
                p += nbytes, pos++, pos_byte += nbytes;
-               UPDATE_SYNTAX_TABLE_FORWARD (pos);
-             }
-         }
-       else
-         {
-           while (1)
-             {
-               if (p >= stop)
-                 {
-                   if (p >= endp)
-                     break;
-                   p = GAP_END_ADDR;
-                   stop = endp;
-                 }
-               if (! fastmap[SYNTAX (*p)])
-                 break;
-               p++, pos++, pos_byte++;
-               UPDATE_SYNTAX_TABLE_FORWARD (pos);
              }
+           while (!parse_sexp_lookup_properties
+                  || pos < gl_state.e_property);
+
+           update_syntax_table_forward (pos + gl_state.offset,
+                                        false, gl_state.object);
          }
       }
     else
       {
+       p = BYTE_POS_ADDR (pos_byte);
+       endp = CHAR_POS_ADDR (XINT (lim));
+       stop = pos >= GPT && GPT > XINT (lim) ? GAP_END_ADDR : endp;
+
        if (multibyte)
          {
            while (1)
@@ -2269,6 +2257,7 @@ skip_syntaxes (bool forwardp, Lisp_Object string, 
Lisp_Object lim)
          }
       }
 
+  done:
     SET_PT_BOTH (pos, pos_byte);
     immediate_quit = 0;