From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 28 Jun 2018 20:49:48 +0000 (-0700)
Subject: Fix recently-introduced SAFE_FREE bug
X-Git-Tag: emacs-27.0.90~4753
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=ddc4371a89e5500e0203bed4b0ad453925b1c74f;p=emacs.git

Fix recently-introduced SAFE_FREE bug

Problem reported by Andy Moreton (Bug#31996).
* src/lisp.h (union specbinding.unwind_array):
Remove unused member func.  Move array after nelts, as this is
likely to generate more efficient code in safe_free, which can
call xfree with the same value either way.
(safe_free): Also handle SPECPDL_UNWIND_AWAY.
---

diff --git a/src/lisp.h b/src/lisp.h
index b544d814d99..cf7b8c0ebc5 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3058,9 +3058,8 @@ union specbinding
     } unwind;
     struct {
       ENUM_BF (specbind_tag) kind : CHAR_BIT;
-      void (*func) (Lisp_Object);
-      Lisp_Object *array;
       ptrdiff_t nelts;
+      Lisp_Object *array;
     } unwind_array;
     struct {
       ENUM_BF (specbind_tag) kind : CHAR_BIT;
@@ -4543,9 +4542,16 @@ safe_free (ptrdiff_t sa_count)
   while (specpdl_ptr != specpdl + sa_count)
     {
       specpdl_ptr--;
-      eassert (specpdl_ptr->kind == SPECPDL_UNWIND_PTR
-	       && specpdl_ptr->unwind_ptr.func == xfree);
-      xfree (specpdl_ptr->unwind_ptr.arg);
+      if (specpdl_ptr->kind == SPECPDL_UNWIND_PTR)
+	{
+	  eassert (specpdl_ptr->unwind_ptr.func == xfree);
+	  xfree (specpdl_ptr->unwind_ptr.arg);
+	}
+      else
+	{
+	  eassert (specpdl_ptr->kind == SPECPDL_UNWIND_ARRAY);
+	  xfree (specpdl_ptr->unwind_array.array);
+	}
     }
 }