Fix SAFE_ALLOCA to not exhaust the stack when in a loop.

Problem reported by Dmietry Antipov in thread leading to:
http://lists.gnu.org/archive/html/emacs-devel/2014-09/msg00713.html
This patch fixes only SAFE_ALLOCA, SAFE_NALLOCA, and SAFE_ALLOCA_LISP;
the experimental local_* macros enabled by USE_LOCAL_ALLOCATORS
remain unfixed.
* callproc.c (call_process): Save and restore sa_avail.
* lisp.h (USE_SAFE_ALLOCA): Define sa_avail.
(AVAIL_ALLOCA): New macro.
(SAFE_ALLOCA, SAFE_NALLOCA, SAFE_ALLOCA_LISP):
Use it, and check against sa_avail rather than MAX_ALLOCA.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 09426cfbf99..02d7871e884 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,17 @@
+2014-09-23  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Fix SAFE_ALLOCA to not exhaust the stack when in a loop.
+        Problem reported by Dmietry Antipov in thread leading to:
+        http://lists.gnu.org/archive/html/emacs-devel/2014-09/msg00713.html
+        This patch fixes only SAFE_ALLOCA, SAFE_NALLOCA, and SAFE_ALLOCA_LISP;
+        the experimental local_* macros enabled by USE_LOCAL_ALLOCATORS
+        remain unfixed.
+        * callproc.c (call_process): Save and restore sa_avail.
+        * lisp.h (USE_SAFE_ALLOCA): Define sa_avail.
+        (AVAIL_ALLOCA): New macro.
+        (SAFE_ALLOCA, SAFE_NALLOCA, SAFE_ALLOCA_LISP):
+        Use it, and check against sa_avail rather than MAX_ALLOCA.
+
 2014-09-22  Dmitry Antipov  <dmantipov@yandex.ru>
 
         On OSX, do not free font-specific data more than once (Bug#18501).