From: Paul Eggert <eggert@cs.ucla.edu>
To: Stefan Monnier <monnier@iro.umontreal.ca>, emacs-devel@gnu.org
Subject: Re: Emacs port to gcc -fcheck-pointer-bounds
Date: Sun, 17 Dec 2017 18:47:38 -0800 [thread overview]
Message-ID: <5f53771e-aee9-9fe1-76a0-8aa1ab9b363e@cs.ucla.edu> (raw)
In-Reply-To: <jwvmv2mv3si.fsf-monnier+gmane.emacs.devel@gnu.org>
[-- Attachment #1: Type: text/plain, Size: 516 bytes --]
Stefan Monnier wrote:
>> and once you have the fake pointer, --enable-check-lisp-object-type
>> doesn't buy much extra safety that is useful.
> It does give us some extra checking, but not very much, indeed.
> Maybe we can turn it into a no-op.
To get the ball rolling on that, I installed the attached into master. This
doesn't turn --enable-check-lisp-object-type into a no-op; it merely goes back
to disabling it by default. We can remove it later if in practice it's not that
helpful to enable it.
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From 5959b48ece0abe4639667c023da6363859088676 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sun, 17 Dec 2017 18:43:14 -0800
Subject: [PATCH] Default CHECK_LISP_OBJECT_TYPE to "no"
* configure.ac: Go back to not defining CHECK_LISP_OBJECT_TYPE by
default for developer builds, since it is no longer that useful.
We can make it a no-op entirely later, if in practice it's not
that helpful to enable it.
---
configure.ac | 7 +++----
etc/NEWS | 7 +++++++
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/configure.ac b/configure.ac
index 562b19a..ec1418b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -900,10 +900,9 @@ AC_DEFUN
AC_ARG_ENABLE([check-lisp-object-type],
[AS_HELP_STRING([--enable-check-lisp-object-type],
- [Enable compile-time checks for the Lisp_Object data type,
- which can catch some bugs during development.
- The default is "no" if --enable-gcc-warnings is "no".])])
-if test "${enable_check_lisp_object_type-$gl_gcc_warnings}" != "no"; then
+ [Enable compile time checks for the Lisp_Object data type,
+ which can catch some bugs during development.])])
+if test "$enable_check_lisp_object_type" = yes; then
AC_DEFINE([CHECK_LISP_OBJECT_TYPE], 1,
[Define to enable compile-time checks for the Lisp_Object data type.])
fi
diff --git a/etc/NEWS b/etc/NEWS
index 1382f96..1ab1930 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -38,6 +38,13 @@ interpreter or modules that it uses. If your platform supports it you
can enable it when configuring, e.g., './configure CFLAGS="-g3 -O2
-mmpx -fcheck-pointer-bounds"' on Intel MPX platforms.
+** Emacs now normally uses a pointer type instead of an integer type
+for the fundamental word in the Emacs Lisp interpreter, to help
+catch typos and support -fcheck-pointer-bounds. The 'configure'
+option --enable-check-lisp-object-type is therefore no longer as
+useful and so is no longer enabled by default in developer builds,
+to reduce differences between developer and production builds.
+
\f
* Startup Changes in Emacs 27.1
--
2.7.4
next prev parent reply other threads:[~2017-12-18 2:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-07 7:34 Emacs port to gcc -fcheck-pointer-bounds Paul Eggert
2017-12-08 13:45 ` Eli Zaretskii
2017-12-08 22:06 ` Paul Eggert
2017-12-09 8:33 ` Eli Zaretskii
2017-12-10 7:10 ` Paul Eggert
2017-12-10 17:27 ` Eli Zaretskii
2017-12-11 7:54 ` Paul Eggert
2017-12-11 15:26 ` Eli Zaretskii
2017-12-12 23:35 ` Paul Eggert
2017-12-13 16:20 ` Eli Zaretskii
2017-12-13 18:30 ` Paul Eggert
2017-12-13 19:17 ` Stefan Monnier
2017-12-13 19:39 ` Paul Eggert
2017-12-18 2:47 ` Paul Eggert [this message]
2017-12-08 16:13 ` Pip Cet
2017-12-08 22:09 ` Paul Eggert
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