[Emacs-diffs] emacs-25 43986d1 2/2: Inhibit buffer relocation during regex searches

[Noam Postavsky]

branch: emacs-25
commit 43986d16fb6ad78a627250e14570ea70bdb1f23a
Author: Noam Postavsky <address@hidden>
Commit: Noam Postavsky <address@hidden>

    Inhibit buffer relocation during regex searches
    
    * src/search.c (looking_at_1, fast_looking_at, search_buffer): Prevent
    relocation of buffer contents during calls to re_search_2.  This ensures
    the pointers into buffer text won't be invalidated by
    r_alloc_sbrk (called from malloc with configurations where
    REL_ALLOC=yes).
---
 src/search.c |   31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/src/search.c b/src/search.c
index fa5ac44..15504be 100644
--- a/src/search.c
+++ b/src/search.c
@@ -308,12 +308,20 @@ looking_at_1 (Lisp_Object string, bool posix)
 
   re_match_object = Qnil;
 
+#ifdef REL_ALLOC
+  /* Prevent ralloc.c from relocating the current buffer while
+     searching it.  */
+  r_alloc_inhibit_buffer_relocation (1);
+#endif
   i = re_match_2 (bufp, (char *) p1, s1, (char *) p2, s2,
                  PT_BYTE - BEGV_BYTE,
                  (NILP (Vinhibit_changing_match_data)
                   ? &search_regs : NULL),
                  ZV_BYTE - BEGV_BYTE);
   immediate_quit = 0;
+#ifdef REL_ALLOC
+  r_alloc_inhibit_buffer_relocation (0);
+#endif
 
   if (i == -2)
     matcher_overflow ();
@@ -561,8 +569,16 @@ fast_looking_at (Lisp_Object regexp, ptrdiff_t pos, 
ptrdiff_t pos_byte,
 
   buf = compile_pattern (regexp, 0, Qnil, 0, multibyte);
   immediate_quit = 1;
+#ifdef REL_ALLOC
+  /* Prevent ralloc.c from relocating the current buffer while
+     searching it.  */
+  r_alloc_inhibit_buffer_relocation (1);
+#endif
   len = re_match_2 (buf, (char *) p1, s1, (char *) p2, s2,
                    pos_byte, NULL, limit_byte);
+#ifdef REL_ALLOC
+  r_alloc_inhibit_buffer_relocation (0);
+#endif
   immediate_quit = 0;
 
   return len;
@@ -1213,6 +1229,12 @@ search_buffer (Lisp_Object string, ptrdiff_t pos, 
ptrdiff_t pos_byte,
        }
       re_match_object = Qnil;
 
+#ifdef REL_ALLOC
+  /* Prevent ralloc.c from relocating the current buffer while
+     searching it.  */
+  r_alloc_inhibit_buffer_relocation (1);
+#endif
+
       while (n < 0)
        {
          ptrdiff_t val;
@@ -1254,6 +1276,9 @@ search_buffer (Lisp_Object string, ptrdiff_t pos, 
ptrdiff_t pos_byte,
          else
            {
              immediate_quit = 0;
+#ifdef REL_ALLOC
+              r_alloc_inhibit_buffer_relocation (0);
+#endif
              return (n);
            }
          n++;
@@ -1296,11 +1321,17 @@ search_buffer (Lisp_Object string, ptrdiff_t pos, 
ptrdiff_t pos_byte,
          else
            {
              immediate_quit = 0;
+#ifdef REL_ALLOC
+              r_alloc_inhibit_buffer_relocation (0);
+#endif
              return (0 - n);
            }
          n--;
        }
       immediate_quit = 0;
+#ifdef REL_ALLOC
+      r_alloc_inhibit_buffer_relocation (0);
+#endif
       return (pos);
     }
   else                         /* non-RE case */