From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 31 Oct 2018 04:14:10 +0000 (-0700)
Subject: Refer to bytecode constant vectors (Bug#33014)
X-Git-Tag: emacs-26.1.90~42
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=1ad2903a48b682985a2bd0709ec05f67a1351a8e;p=emacs.git

Refer to bytecode constant vectors (Bug#33014)

Backport from master.
* src/bytecode.c (exec_byte_code): Save VECTOR into stack slot
so that it survives GC.  The stack slot was otherwise unused,
so this doesn’t cost us memory, only a store insn.
---

diff --git a/src/bytecode.c b/src/bytecode.c
index e51f9095b36..538cd4f3ca7 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -367,6 +367,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
   SAFE_ALLOCA_LISP_EXTRA (stack_base, stack_items, bytestr_length);
   Lisp_Object *stack_lim = stack_base + stack_items;
   Lisp_Object *top = stack_base;
+  *top = vector; /* Ensure VECTOR survives GC (Bug#33014).  */
   memcpy (stack_lim, SDATA (bytestr), bytestr_length);
   void *void_stack_lim = stack_lim;
   unsigned char const *bytestr_data = void_stack_lim;