Tune SAFE_FREE

On my platform (Fedora 28 x86-64, AMD Phenom II X4 910e) this sped
up a SAFE_FREE-using microbenchmark (string-distance "abc" "abc")
by about 18%, and shrank the Emacs text size by about 0.1%.
* src/callint.c (Fcall_interactively):
* src/callproc.c (call_process):
* src/doc.c (get_doc_string, Fsnarf_documentation):
* src/editfns.c (Freplace_buffer_contents):
* src/emacs-module.c (funcall_module):
* src/eval.c (Flet):
* src/process.c (Fmake_process):
* src/term.c (tty_menu_show):
* src/xdisp.c (safe__call):
* src/xmenu.c (x_menu_show):
Use SAFE_FREE_UNBIND_TO.
* src/data.c (wrong_choice): No need to call SAFE_FREE here.
* src/lisp.h (USE_SAFE_ALLOCA):
* src/regex.c (REGEX_USE_SAFE_ALLOCA):
Do not declare sa_must_free local; no longer needed.
All uses removed.
(SAFE_FREE): Rewrite in terms of safe_free.
(safe_free): New function, optimized to use xfree.
(SAFE_FREE_UNBIND_TO): New macro.
(safe_free_unbind_to): New function.

1 files changed, 3 insertions, 6 deletions

diff --git a/src/doc.c b/src/doc.c
index 4264ed50640..075154e94bc 100644
--- a/src/doc.c
+++ b/src/doc.c
@@ -86,7 +86,7 @@ get_doc_string (Lisp_Object filepos, bool unibyte, bool definition)
   int offset;
   EMACS_INT position;
   Lisp_Object file, tem, pos;
-  ptrdiff_t count;
+  ptrdiff_t count = SPECPDL_INDEX ();
   USE_SAFE_ALLOCA;
 
   if (INTEGERP (filepos))
@@ -148,7 +148,6 @@ get_doc_string (Lisp_Object filepos, bool unibyte, bool definition)
           return concat3 (cannot_open, file, quote_nl);
         }
     }
-  count = SPECPDL_INDEX ();
   record_unwind_protect_int (close_file_unwind, fd);
 
   /* Seek only to beginning of disk block.  */
@@ -204,8 +203,7 @@ get_doc_string (Lisp_Object filepos, bool unibyte, bool definition)
         }
       p += nread;
     }
-  unbind_to (count, Qnil);
-  SAFE_FREE ();
+  SAFE_FREE_UNBIND_TO (count, Qnil);
 
   /* Sanity checking.  */
   if (CONSP (filepos))
@@ -659,8 +657,7 @@ the same file name is found in the `doc-directory'.  */)
       memmove (buf, end, filled);
     }
 
-  SAFE_FREE ();
-  return unbind_to (count, Qnil);
+  return SAFE_FREE_UNBIND_TO (count, Qnil);
 }
 
 /* Return true if text quoting style should default to quote `like this'.  */