database/postgres
database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-04-18 13:44:19 +03:00
Code

Disable -faggressive-loop-optimizations in gcc 4.8+ for pre-9.2 branches.

Browse Source 
With this optimization flag enabled, recent versions of gcc can generate
incorrect code that assumes variable-length arrays (such as oidvector)
are actually fixed-length because they're embedded in some larger struct.
The known instance of this problem was fixed in 9.2 and up by commit
8137f2c32322c624e0431fac1621e8e9315202f9 and followon work, which hides
actually-variable-length catalog fields from the compiler altogether.
And we plan to gradually convert variable-length fields to official
"flexible array member" notation over time, which should prevent this type
of bug from reappearing as gcc gets smarter.  We're not going to try to
back-port those changes into older branches, though, so apply this
band-aid instead.

Andres Freund

This is a backpatch of commit 649839dd9 to unsupported branches
REL8_2_STABLE and REL8_3_STABLE, so that they work with newer toolsets.
This commit is contained in:
Alvaro Herrera 2015-01-20 12:26:20 -03:00
parent 91a1e14899
commit 105f3ef492
2 changed files with 58 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
configure vendored
View File

@ -3188,6 +3188,61 @@ else
echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
CFLAGS="$pgac_save_CFLAGS"
echo "$as_me:$LINENO: result: no" >&5
echo "${ECHO_T}no" >&6
fi
rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
# Disable loop optimizations that get confused by variable-length struct
# declarations in gcc 4.8+
echo "$as_me:$LINENO: checking if $CC supports -fno-aggressive-loop-optimizations" >&5
echo $ECHO_N "checking if $CC supports -fno-aggressive-loop-optimizations... $ECHO_C" >&6
pgac_save_CFLAGS=$CFLAGS
CFLAGS="$pgac_save_CFLAGS -fno-aggressive-loop-optimizations"
cat >conftest.$ac_ext <<_ACEOF
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
int
main ()
{
;
return 0;
}
_ACEOF
rm -f conftest.$ac_objext
if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
(eval $ac_compile) 2>conftest.er1
ac_status=$?
grep -v '^ *+' conftest.er1 >conftest.err
rm -f conftest.er1
cat conftest.err >&5
echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); } &&
{ ac_try='test -z "$ac_c_werror_flag"
|| test ! -s conftest.err'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; } &&
{ ac_try='test -s conftest.$ac_objext'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; }; then
echo "$as_me:$LINENO: result: yes" >&5
echo "${ECHO_T}yes" >&6
else
echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
CFLAGS="$pgac_save_CFLAGS"
echo "$as_me:$LINENO: result: no" >&5
echo "${ECHO_T}no" >&6

3
configure.in
View File

@ -294,6 +294,9 @@ choke me
PGAC_PROG_CC_CFLAGS_OPT([-fwrapv])
# Disable FP optimizations that cause various errors on gcc 4.5+ or maybe 4.6+
PGAC_PROG_CC_CFLAGS_OPT([-fexcess-precision=standard])
# Disable loop optimizations that get confused by variable-length struct
# declarations in gcc 4.8+
PGAC_PROG_CC_CFLAGS_OPT([-fno-aggressive-loop-optimizations])
elif test x"${CC}" = x"xlc"; then
# AIX xlc has to have strict aliasing turned off too
PGAC_PROG_CC_CFLAGS_OPT([-qnoansialias])