From: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri, 4 Oct 2013 06:51:50 +0000 (-0700)
Subject: * bytecode.c (exec_byte_code): Use some more volatile variables
X-Git-Tag: emacs-24.3.90~173^2^2~42^2~45^2~387^2~1395
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=157fec2e190a84345138a0cc69e35f177c4d4a56;p=emacs.git

* bytecode.c (exec_byte_code): Use some more volatile variables

to work around local variables getting clobbered by longjmp.
Port to pre-C99, which doesn't allow decls after stmts.
---

diff --git a/src/ChangeLog b/src/ChangeLog
index 85411622ba1..4fae03d6965 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2013-10-04  Paul Eggert  <eggert@cs.ucla.edu>
+
+	* bytecode.c (exec_byte_code): Use some more volatile variables
+	to work around local variables getting clobbered by longjmp.
+	Port to pre-C99, which doesn't allow decls after stmts.
+
 2013-10-03  Paul Eggert  <eggert@cs.ucla.edu>
 
 	* lisp.h (eassert): Assume that COND is true when optimizing.
diff --git a/src/bytecode.c b/src/bytecode.c
index f7ccd35cbba..b9cb36c871f 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -332,7 +332,7 @@ struct byte_stack
 
 /* A list of currently active byte-code execution value stacks.
    Fbyte_code adds an entry to the head of this list before it starts
-   processing byte-code, and it removed the entry again when it is
+   processing byte-code, and it removes the entry again when it is
    done.  Signaling an error truncates the list analogous to
    gcprolist.  */
 
@@ -501,19 +501,22 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
 		Lisp_Object args_template, ptrdiff_t nargs, Lisp_Object *args)
 {
   ptrdiff_t count = SPECPDL_INDEX ();
+  ptrdiff_t volatile count_volatile;
 #ifdef BYTE_CODE_METER
-  int this_op = 0;
+  int volatile this_op = 0;
   int prev_op;
 #endif
   int op;
   /* Lisp_Object v1, v2; */
   Lisp_Object *vectorp;
+  Lisp_Object *volatile vectorp_volatile;
 #ifdef BYTE_CODE_SAFE
-  ptrdiff_t const_length;
-  Lisp_Object *stacke;
-  ptrdiff_t bytestr_length;
+  ptrdiff_t volatile const_length;
+  Lisp_Object *volatile stacke;
+  ptrdiff_t volatile bytestr_length;
 #endif
   struct byte_stack stack;
+  struct byte_stack volatile stack_volatile;
   Lisp_Object *top;
   Lisp_Object result;
   enum handlertype type;
@@ -1119,16 +1122,25 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
 	    PUSH_HANDLER (c, tag, type);
 	    c->bytecode_dest = dest;
 	    c->bytecode_top = top;
+	    count_volatile = count;
+	    stack_volatile = stack;
+	    vectorp_volatile = vectorp;
+
 	    if (sys_setjmp (c->jmp))
 	      {
 		struct handler *c = handlerlist;
+		int dest;
 		top = c->bytecode_top;
-		int dest = c->bytecode_dest;
+		dest = c->bytecode_dest;
 		handlerlist = c->next;
 		PUSH (c->val);
 		CHECK_RANGE (dest);
+		stack = stack_volatile;
 		stack.pc = stack.byte_string_start + dest;
 	      }
+
+	    count = count_volatile;
+	    vectorp = vectorp_volatile;
 	    NEXT;
 	  }