[binutils-gdb] Disable the undefined behavior sanitizer by default

[Tom Tromey <tromey at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=eff98030f90d3dab4c7d133ab0b0cb02d1921543

commit eff98030f90d3dab4c7d133ab0b0cb02d1921543
Author: Tom Tromey <tom@tromey.com>
Date:   Tue Oct 9 11:51:33 2018 -0600

    Disable the undefined behavior sanitizer by default
    
    There have been a few undefined behavior failures reported, and Pedro
    suggested that the sanitizer be disabled by default.  This patch
    implements this.
    
    gdb/ChangeLog
    2018-10-09  Tom Tromey  <tom@tromey.com>
    
    	* configure: Rebuild.
    	* sanitize.m4 (AM_GDB_UBSAN): Default to no.
    	* NEWS: Update --enable-ubsan documentation.
    
    gdb/doc/ChangeLog
    2018-10-09  Tom Tromey  <tom@tromey.com>
    
    	* gdb.texinfo (Configure Options): Update --enable-ubsan
    	documentation.

Diff:
---
 gdb/ChangeLog       |  6 ++++++
 gdb/NEWS            | 10 +++++-----
 gdb/configure       |  2 +-
 gdb/doc/ChangeLog   |  5 +++++
 gdb/doc/gdb.texinfo | 13 +++++++------
 gdb/sanitize.m4     |  2 +-
 6 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f37070e..f9e56be 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2018-10-09  Tom Tromey  <tom@tromey.com>
+
+	* configure: Rebuild.
+	* sanitize.m4 (AM_GDB_UBSAN): Default to no.
+	* NEWS: Update --enable-ubsan documentation.
+
 2018-10-09  Gary Benson <gbenson@redhat.com>
 
 	* dwarf2read.c (create_dwp_hash_table): Fix buffer overrun
diff --git a/gdb/NEWS b/gdb/NEWS
index 8a0dd52..126e61e 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -122,11 +122,11 @@ FreeBSD/riscv			riscv*-*-freebsd*
 
 --enable-ubsan
 
-  Enable or disable the undefined behavior sanitizer.  Release
-  versions of GDB disable this by default if it is available, but
-  development versions enable it.  Enabling this can cause a
-  performance penalty.  The undefined behavior sanitizer was first
-  introduced in GCC 4.9.
+  Enable or disable the undefined behavior sanitizer.  This is
+  disabled by default, but passing --enable-ubsan=yes or
+  --enable-ubsan=auto to configure will enable it.  Enabling this can
+  cause a performance penalty.  The undefined behavior sanitizer was
+  first introduced in GCC 4.9.
 
 *** Changes in GDB 8.2
 
diff --git a/gdb/configure b/gdb/configure
index 304adc8..adb26e5 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -15614,7 +15614,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 if test "${enable_ubsan+set}" = set; then :
   enableval=$enable_ubsan;
 else
-  enable_ubsan=auto
+  enable_ubsan=no
 fi
 
 if test "x$enable_ubsan" = xauto; then
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index a3aace7..c677983 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,8 @@
+2018-10-09  Tom Tromey  <tom@tromey.com>
+
+	* gdb.texinfo (Configure Options): Update --enable-ubsan
+	documentation.
+
 2018-10-08  John Baldwin  <jhb@FreeBSD.org>
 
 	* gdb.texinfo (Contributors): Add SRI International and University
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index efd6dff..b0dc3bf 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -35771,12 +35771,13 @@ to the compiler, which will fail the compilation if the compiler
 outputs any warning messages.
 
 @item --enable-ubsan
-Enable the GCC undefined behavior sanitizer.  By default this is
-disabled in @value{GDBN} releases, but enabled, when available, when
-building from git.  The undefined behavior sanitizer checks for
-C@t{++} undefined behavior.  It has a performance cost, so if you are
-looking at @value{GDBN}'s performance, you should disable it.  The
-undefined behavior sanitizer was first introduced in GCC 4.9.
+Enable the GCC undefined behavior sanitizer.  This is disabled by
+default, but passing @code{--enable-ubsan=yes} or
+@code{--enable-ubsan=auto} to @code{configure} will enable it.  The
+undefined behavior sanitizer checks for C@t{++} undefined behavior.
+It has a performance cost, so if you are looking at @value{GDBN}'s
+performance, you should disable it.  The undefined behavior sanitizer
+was first introduced in GCC 4.9.
 @end table
 
 @node System-wide configuration
diff --git a/gdb/sanitize.m4 b/gdb/sanitize.m4
index 76df44d..979f646 100644
--- a/gdb/sanitize.m4
+++ b/gdb/sanitize.m4
@@ -20,7 +20,7 @@ AC_DEFUN([AM_GDB_UBSAN],[
 AC_ARG_ENABLE(ubsan,
   AS_HELP_STRING([--enable-ubsan],
                  [enable undefined behavior sanitizer (auto/yes/no)]),
-  [],enable_ubsan=auto)
+  [],enable_ubsan=no)
 if test "x$enable_ubsan" = xauto; then
   if $development; then
     enable_ubsan=yes