Re: -znocombreloc?

[Paul Eggert <eggert@cs.ucla.edu>]

[-- Attachment #1: Type: text/plain, Size: 661 bytes --]

Daniel Colascione wrote:
> Does anyone remember _why_ temacs segfaults on startup unless we give ld this
> option?

It doesn't segfault for me, even when I build with -zcombreloc. I think 
-znocombreloc worked around bugs in now-obsolete versions of the GNU linker. 
See, for example:

https://lists.gnu.org/archive/html/bug-gnu-emacs/2004-02/msg00278.html
https://lists.gnu.org/archive/html/help-gnu-emacs/2003-05/msg00627.html

Looking at recent GCC documentation it appears that this old hack should not 
matter now, so I'm inclined to remove it, as in the proposed patch (attached), 
which I tested on Fedora 24 x86-64 but have not installed.

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Remove-old-znocombreloc-hack.patch --]
[-- Type: text/x-diff; name="0001-Remove-old-znocombreloc-hack.patch", Size: 3179 bytes --]

From fe4a24b33bb72610cf6703143cf910d7eef547b6 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 3 Dec 2016 21:29:06 -0800
Subject: [PATCH] Remove old -znocombreloc hack

It no longer seems relevant.  See the thread starting at:
http://lists.gnu.org/archive/html/emacs-devel/2016-12/msg00142.html
* configure.ac (LDFLAGS_NOCOMBRELOC): Remove.
(LD_SWITCH_SYSTEM_TEMACS): Do not test for -znocombreloc.
* etc/PROBLEMS: Update problem description.
---
 configure.ac | 32 --------------------------------
 etc/PROBLEMS |  7 +++----
 2 files changed, 3 insertions(+), 36 deletions(-)

diff --git a/configure.ac b/configure.ac
index 2d116de..65b963c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1272,36 +1272,6 @@ AC_DEFUN
     ac_link="$ac_link $NON_GCC_LINK_TEST_OPTIONS"
 fi
 
-dnl We need -znocombreloc if we're using a relatively recent GNU ld.
-dnl If we can link with the flag, it shouldn't do any harm anyhow.
-dnl Treat GCC specially since it just gives a non-fatal 'unrecognized option'
-dnl if not built to support GNU ld.
-
-dnl For a long time, -znocombreloc was added to LDFLAGS rather than
-dnl LD_SWITCH_SYSTEM_TEMACS.  That is:
-dnl * inappropriate, as LDFLAGS is a user option but this is essential.
-dnl   Eg "make LDFLAGS=... all" could run into problems,
-dnl   http://bugs.debian.org/684788
-dnl * unnecessary, since temacs is the only thing that actually needs it.
-dnl   Indeed this is where it was originally, prior to:
-dnl   http://lists.gnu.org/archive/html/emacs-pretest-bug/2004-03/msg00170.html
-late_LDFLAGS="$LDFLAGS"
-if test x$GCC = xyes; then
-  LDFLAGS_NOCOMBRELOC="-Wl,-znocombreloc"
-else
-  LDFLAGS_NOCOMBRELOC="-znocombreloc"
-fi
-
-LDFLAGS="$LDFLAGS $LDFLAGS_NOCOMBRELOC"
-
-AC_MSG_CHECKING([for -znocombreloc])
-AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
-  [AC_MSG_RESULT(yes)],
-  LDFLAGS_NOCOMBRELOC=
-  [AC_MSG_RESULT(no)])
-
-LDFLAGS="$late_LDFLAGS"
-
 AC_CACHE_CHECK([whether addresses are sanitized],
   [emacs_cv_sanitize_address],
   [AC_COMPILE_IFELSE(
@@ -5176,8 +5146,6 @@ AC_DEFUN
   esac
 fi
 
-LD_SWITCH_SYSTEM_TEMACS="$LDFLAGS_NOCOMBRELOC $LD_SWITCH_SYSTEM_TEMACS"
-
 AC_SUBST(LD_SWITCH_SYSTEM_TEMACS)
 
 ## Common for all window systems
diff --git a/etc/PROBLEMS b/etc/PROBLEMS
index c9b11fbc5..82c727f 100644
--- a/etc/PROBLEMS
+++ b/etc/PROBLEMS
@@ -196,10 +196,9 @@ as Xming or Cygwin/X.
 
 It crashes on X, but runs fine when called with option "-nw".
 
-This has been observed when Emacs is linked with GNU ld but without passing
-the -z nocombreloc flag.  Emacs normally knows to pass the -z nocombreloc
-flag when needed, so if you come across a situation where the flag is
-necessary but missing, please report it via M-x report-emacs-bug.
+This was observed when Emacs was linked with old versions of GNU ld.
+If this happens, please file a bug report and mention the ld version.
+Configuring with LDFLAGS="-Wl,-znocombreloc" may fix the problem.
 
 On platforms such as Solaris, you can also work around this problem by
 configuring your compiler to use the native linker instead of GNU ld.
-- 
2.7.4