Fix quitting bug when buffers are frozen

Problem noted by Eli Zaretskii in:
http://lists.gnu.org/archive/html/emacs-devel/2017-01/msg00721.html
This patch also fixes some other issues in that report.
* src/lisp.h (incr_rarely_quit): Remove.
All callers changed to use rarely_quit directly.
* src/search.c (freeze_buffer_relocation)
(thaw_buffer_relocation): New functions.
(looking_at_1, fast_looking_at, search_buffer):
Use them to fix bug when quitting when buffers are frozen.
* src/sysdep.c (emacs_intr_read): Rename from emacs_nointr_read.
All uses changed.

7 files changed, 70 insertions, 80 deletions

diff --git a/src/callproc.c b/src/callproc.c
index 710174c46b0..84324c48dcf 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -198,7 +198,10 @@ call_process_cleanup (Lisp_Object buffer)
     {
       kill (-synch_process_pid, SIGINT);
       message1 ("Waiting for process to die...(type C-g again to kill it instantly)");
+
+      /* This will quit on C-g.  */
       wait_for_termination (synch_process_pid, 0, 1);
+
       synch_process_pid = 0;
       message1 ("Waiting for process to die...done");
     }
diff --git a/src/fns.c b/src/fns.c
index 41c0c5856b4..ac7c1f265a4 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -1389,7 +1389,7 @@ The value is actually the tail of LIST whose car is ELT.  */)
     {
       if (! NILP (Fequal (elt, XCAR (tail))))
         return tail;
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   CHECK_LIST_END (tail, list);
   return Qnil;
@@ -1406,7 +1406,7 @@ The value is actually the tail of LIST whose car is ELT.  */)
     {
       if (EQ (XCAR (tail), elt))
         return tail;
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   CHECK_LIST_END (tail, list);
   return Qnil;
@@ -1427,7 +1427,7 @@ The value is actually the tail of LIST whose car is ELT.  */)
       Lisp_Object tem = XCAR (tail);
       if (FLOATP (tem) && internal_equal (elt, tem, 0, 0, Qnil))
         return tail;
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   CHECK_LIST_END (tail, list);
   return Qnil;
@@ -1445,7 +1445,7 @@ Elements of LIST that are not conses are ignored.  */)
     {
       if (CONSP (XCAR (tail)) && EQ (XCAR (XCAR (tail)), key))
         return XCAR (tail);
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   CHECK_LIST_END (tail, list);
   return Qnil;
@@ -1476,7 +1476,7 @@ The value is actually the first element of LIST whose car equals KEY.  */)
       if (CONSP (car)
           && (EQ (XCAR (car), key) || !NILP (Fequal (XCAR (car), key))))
         return car;
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   CHECK_LIST_END (tail, list);
   return Qnil;
@@ -1509,7 +1509,7 @@ The value is actually the first element of LIST whose cdr is KEY.  */)
     {
       if (CONSP (XCAR (tail)) && EQ (XCDR (XCAR (tail)), key))
         return XCAR (tail);
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   CHECK_LIST_END (tail, list);
   return Qnil;
@@ -1528,7 +1528,7 @@ The value is actually the first element of LIST whose cdr equals KEY.  */)
       if (CONSP (car)
           && (EQ (XCDR (car), key) || !NILP (Fequal (XCDR (car), key))))
         return car;
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   CHECK_LIST_END (tail, list);
   return Qnil;
@@ -1684,7 +1684,7 @@ changing the value of a sequence `foo'.  */)
             }
           else
             prev = tail;
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
         }
       CHECK_LIST_END (tail, seq);
     }
@@ -1712,7 +1712,7 @@ This function may destructively modify SEQ to produce the value.  */)
           next = XCDR (tail);
           Fsetcdr (tail, prev);
           prev = tail;
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
         }
       CHECK_LIST_END (tail, seq);
       seq = prev;
@@ -1759,7 +1759,7 @@ See also the function `nreverse', which is used more often.  */)
       for (new = Qnil; CONSP (seq); seq = XCDR (seq))
         {
           new = Fcons (XCAR (seq), new);
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
         }
       CHECK_LIST_END (seq, seq);
     }
@@ -2062,7 +2062,7 @@ The PLIST is modified by side effects.  */)
         }
 
       prev = tail;
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   Lisp_Object newcell
     = Fcons (prop, Fcons (val, NILP (prev) ? plist : XCDR (XCDR (prev))));
@@ -2100,7 +2100,7 @@ one of the properties on the list.  */)
     {
       if (! NILP (Fequal (prop, XCAR (tail))))
         return XCAR (XCDR (tail));
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
 
   CHECK_LIST_END (tail, prop);
@@ -2130,7 +2130,7 @@ The PLIST is modified by side effects.  */)
         }
 
       prev = tail;
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   Lisp_Object newcell = list2 (prop, val);
   if (NILP (prev))
@@ -2210,7 +2210,7 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, int depth, bool props,
 
   unsigned short int quit_count = 0;
  tail_recurse:
-  incr_rarely_quit (&quit_count);
+  rarely_quit (++quit_count);
   if (EQ (o1, o2))
     return 1;
   if (XTYPE (o1) != XTYPE (o2))
@@ -2419,7 +2419,7 @@ usage: (nconc &rest LISTS)  */)
         {
           tail = tem;
           tem = XCDR (tail);
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
         }
       while (CONSP (tem));
 
@@ -2848,7 +2848,7 @@ The value is actually the tail of PLIST whose car is PROP.  */)
     {
       plist = XCDR (plist);
       plist = CDR (plist);
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   return plist;
 }
diff --git a/src/indent.c b/src/indent.c
index aff14abfd20..f630ebb847c 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -1215,7 +1215,7 @@ compute_motion (ptrdiff_t from, ptrdiff_t frombyte, EMACS_INT fromvpos,
 
   while (true)
     {
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
 
       while (pos == next_boundary)
         {
@@ -1282,7 +1282,7 @@ compute_motion (ptrdiff_t from, ptrdiff_t frombyte, EMACS_INT fromvpos,
               pos_byte = CHAR_TO_BYTE (pos);
             }
 
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
         }
 
       /* Handle right margin.  */
@@ -1605,7 +1605,7 @@ compute_motion (ptrdiff_t from, ptrdiff_t frombyte, EMACS_INT fromvpos,
                               pos = find_before_next_newline (pos, to, 1, &pos_byte);
                               if (pos < to)
                                 INC_BOTH (pos, pos_byte);
-                              incr_rarely_quit (&quit_count);
+                              rarely_quit (++quit_count);
                             }
                           while (pos < to
                                  && indented_beyond_p (pos, pos_byte,
diff --git a/src/lisp.h b/src/lisp.h
index 2d67e7edddb..1ac38164c27 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3145,14 +3145,6 @@ rarely_quit (unsigned short int count)
   if (! (count & (QUIT_COUNT_HEURISTIC - 1)))
     maybe_quit ();
 }
-
-/* Increment *QUIT_COUNT and rarely quit.  */
-
-INLINE void
-incr_rarely_quit (unsigned short int *quit_count)
-{
-  rarely_quit (++*quit_count);
-}
 
 extern Lisp_Object Vascii_downcase_table;
 extern Lisp_Object Vascii_canon_table;
diff --git a/src/search.c b/src/search.c
index 084adda097b..33cb02aa7af 100644
--- a/src/search.c
+++ b/src/search.c
@@ -99,6 +99,25 @@ matcher_overflow (void)
   error ("Stack overflow in regexp matcher");
 }
 
+static void
+freeze_buffer_relocation (void)
+{
+#ifdef REL_ALLOC
+  /* Prevent ralloc.c from relocating the current buffer while
+     searching it.  */
+  r_alloc_inhibit_buffer_relocation (1);
+  record_unwind_protect_int (r_alloc_inhibit_buffer_relocation, 0);
+#endif
+}
+
+static void
+thaw_buffer_relocation (void)
+{
+#ifdef REL_ALLOC
+  unbind_to (SPECPDL_INDEX () - 1, Qnil);
+#endif
+}
+
 /* Compile a regexp and signal a Lisp error if anything goes wrong.
    PATTERN is the pattern to compile.
    CP is the place to put the result.
@@ -300,19 +319,13 @@ 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
+  freeze_buffer_relocation ();
   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);
-#ifdef REL_ALLOC
-  r_alloc_inhibit_buffer_relocation (0);
-#endif
+  thaw_buffer_relocation ();
 
   if (i == -2)
     matcher_overflow ();
@@ -553,16 +566,10 @@ fast_looking_at (Lisp_Object regexp, ptrdiff_t pos, ptrdiff_t pos_byte,
     }
 
   buf = compile_pattern (regexp, 0, Qnil, 0, multibyte);
-#ifdef REL_ALLOC
-  /* Prevent ralloc.c from relocating the current buffer while
-     searching it.  */
-  r_alloc_inhibit_buffer_relocation (1);
-#endif
+  freeze_buffer_relocation ();
   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
+  thaw_buffer_relocation ();
 
   return len;
 }
@@ -1204,11 +1211,7 @@ 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
+      freeze_buffer_relocation ();
 
       while (n < 0)
         {
@@ -1250,9 +1253,7 @@ search_buffer (Lisp_Object string, ptrdiff_t pos, ptrdiff_t pos_byte,
             }
           else
             {
-#ifdef REL_ALLOC
-              r_alloc_inhibit_buffer_relocation (0);
-#endif
+              thaw_buffer_relocation ();
               return (n);
             }
           n++;
@@ -1295,17 +1296,13 @@ search_buffer (Lisp_Object string, ptrdiff_t pos, ptrdiff_t pos_byte,
             }
           else
             {
-#ifdef REL_ALLOC
-              r_alloc_inhibit_buffer_relocation (0);
-#endif
+              thaw_buffer_relocation ();
               return (0 - n);
             }
           n--;
           maybe_quit ();
         }
-#ifdef REL_ALLOC
-      r_alloc_inhibit_buffer_relocation (0);
-#endif
+      thaw_buffer_relocation ();
       return (pos);
     }
   else                          /* non-RE case */
diff --git a/src/syntax.c b/src/syntax.c
index 06fe50b866b..7aa43e6e5c7 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -593,7 +593,6 @@ static ptrdiff_t
 find_defun_start (ptrdiff_t pos, ptrdiff_t pos_byte)
 {
   ptrdiff_t opoint = PT, opoint_byte = PT_BYTE;
-  unsigned short int quit_count = 0;
 
   /* Use previous finding, if it's valid and applies to this inquiry.  */
   if (current_buffer == find_start_buffer
@@ -636,7 +635,6 @@ find_defun_start (ptrdiff_t pos, ptrdiff_t pos_byte)
         }
       /* Move to beg of previous line.  */
       scan_newline (PT, PT_BYTE, BEGV, BEGV_BYTE, -2, 1);
-      incr_rarely_quit (&quit_count);
     }
 
   /* Record what we found, for the next try.  */
@@ -725,7 +723,7 @@ back_comment (ptrdiff_t from, ptrdiff_t from_byte, ptrdiff_t stop,
      that determines quote parity to the comment-end.  */
   while (from != stop)
     {
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
 
       ptrdiff_t temp_byte;
       int prev_syntax;
@@ -954,7 +952,7 @@ back_comment (ptrdiff_t from, ptrdiff_t from_byte, ptrdiff_t stop,
                   defun_start_byte = CHAR_TO_BYTE (defun_start);
                 }
             }
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
         }
       while (defun_start < comment_end);
 
@@ -2386,7 +2384,7 @@ forw_comment (ptrdiff_t from, ptrdiff_t from_byte, ptrdiff_t stop,
           nesting++;
         }
 
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
     }
   *charpos_ptr = from;
   *bytepos_ptr = from_byte;
@@ -2460,7 +2458,7 @@ between them, return t; otherwise return nil.  */)
               INC_BOTH (from, from_byte);
               UPDATE_SYNTAX_TABLE_FORWARD (from);
             }
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
         }
       while (code == Swhitespace || (code == Sendcomment && c == '\n'));
 
@@ -2544,7 +2542,7 @@ between them, return t; otherwise return nil.  */)
                     }
                   else if (from == stop)
                     break;
-                  incr_rarely_quit (&quit_count);
+                  rarely_quit (++quit_count);
                 }
               if (fence_found == 0)
                 {
@@ -2592,7 +2590,7 @@ between them, return t; otherwise return nil.  */)
               return Qnil;
             }
 
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
         }
 
       count1++;
@@ -2648,7 +2646,7 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
     {
       while (from < stop)
         {
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
           bool comstart_first, prefix;
           int syntax, other_syntax;
           UPDATE_SYNTAX_TABLE_FORWARD (from);
@@ -2717,7 +2715,7 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
                       goto done;
                     }
                   INC_BOTH (from, from_byte);
-                  incr_rarely_quit (&quit_count);
+                  rarely_quit (++quit_count);
                 }
               goto done;
 
@@ -2789,7 +2787,7 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
                   if (c_code == Scharquote || c_code == Sescape)
                     INC_BOTH (from, from_byte);
                   INC_BOTH (from, from_byte);
-                  incr_rarely_quit (&quit_count);
+                  rarely_quit (++quit_count);
                 }
               INC_BOTH (from, from_byte);
               if (!depth && sexpflag) goto done;
@@ -2815,7 +2813,7 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
     {
       while (from > stop)
         {
-          incr_rarely_quit (&quit_count);
+          rarely_quit (++quit_count);
           DEC_BOTH (from, from_byte);
           UPDATE_SYNTAX_TABLE_BACKWARD (from);
           c = FETCH_CHAR_AS_MULTIBYTE (from_byte);
@@ -2891,7 +2889,7 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
                       default: goto done2;
                       }
                   DEC_BOTH (from, from_byte);
-                  incr_rarely_quit (&quit_count);
+                  rarely_quit (++quit_count);
                 }
               goto done2;
 
@@ -2954,7 +2952,7 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
                       if (syntax_multibyte (c, multibyte_symbol_p) == code)
                         break;
                     }
-                  incr_rarely_quit (&quit_count);
+                  rarely_quit (++quit_count);
                 }
               if (code == Sstring_fence && !depth && sexpflag) goto done2;
               break;
@@ -2975,7 +2973,7 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
                               == Sstring))
                         break;
                     }
-                  incr_rarely_quit (&quit_count);
+                  rarely_quit (++quit_count);
                 }
               if (!depth && sexpflag) goto done2;
               break;
@@ -3229,7 +3227,7 @@ do { prev_from = from;				\
 
   while (from < end)
     {
-      incr_rarely_quit (&quit_count);
+      rarely_quit (++quit_count);
       INC_FROM;
 
       if ((from < end)
@@ -3286,7 +3284,7 @@ do { prev_from = from;				\
                   goto symdone;
                 }
               INC_FROM;
-              incr_rarely_quit (&quit_count);
+              rarely_quit (++quit_count);
             }
         symdone:
           curlevel->prev = curlevel->last;
@@ -3397,7 +3395,7 @@ do { prev_from = from;				\
                     break;
                   }
                 INC_FROM;
-                incr_rarely_quit (&quit_count);
+                rarely_quit (++quit_count);
               }
           }
         string_end:
diff --git a/src/sysdep.c b/src/sysdep.c
index 4155c205712..91b2a5cb943 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -2508,12 +2508,12 @@ emacs_close (int fd)
 #endif
 
 /* Read from FD to a buffer BUF with size NBYTE.
-   If interrupted, either quit or retry the read.
-   Process any quits and pending signals immediately if INTERRUPTIBLE.
+   If interrupted, process any quits and pending signals immediately
+   if INTERRUPTIBLE, and then retry the read unless quitting.
    Return the number of bytes read, which might be less than NBYTE.
    On error, set errno to a value other than EINTR, and return -1.  */
 static ptrdiff_t
-emacs_nointr_read (int fd, void *buf, ptrdiff_t nbyte, bool interruptible)
+emacs_intr_read (int fd, void *buf, ptrdiff_t nbyte, bool interruptible)
 {
   ssize_t result;
 
@@ -2537,14 +2537,14 @@ emacs_nointr_read (int fd, void *buf, ptrdiff_t nbyte, bool interruptible)
 ptrdiff_t
 emacs_read (int fd, void *buf, ptrdiff_t nbyte)
 {
-  return emacs_nointr_read (fd, buf, nbyte, false);
+  return emacs_intr_read (fd, buf, nbyte, false);
 }
 
 /* Like emacs_read, but also process quits and pending signals.  */
 ptrdiff_t
 emacs_read_quit (int fd, void *buf, ptrdiff_t nbyte)
 {
-  return emacs_nointr_read (fd, buf, nbyte, true);
+  return emacs_intr_read (fd, buf, nbyte, true);
 }
 
 /* Write to FILEDES from a buffer BUF with size NBYTE, retrying if