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compile with -fno-omit-frame-pointer 

By default, depending on the version, gcc can reuse the frame pointer register.
This is a micro-optimization that might help on some very old x86 processors.
However, it also makes dynamic tracing less useful because the stacks cannot
be easily observed.

This rule change instructs gcc to use the -fno-omit-frame-pointer option
when compiling.

Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Elling <Richard.Elling@RichardElling.com>
Closes #8617
This commit is contained in:
Richard Elling 2019-04-14 11:04:54 -07:00 committed by Brian Behlendorf
parent 7dcd318832
commit d5d2ef2b26
3 changed files with 23 additions and 0 deletions
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1
config/Rules.am
View File

@ -8,6 +8,7 @@ DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h
AM_LIBTOOLFLAGS = --silent
AM_CFLAGS = -std=gnu99 -Wall -Wstrict-prototypes -fno-strict-aliasing
AM_CFLAGS += $(NO_OMIT_FRAME_POINTER)
AM_CFLAGS += $(DEBUG_CFLAGS)
AM_CFLAGS += $(ASAN_CFLAGS)
AM_CFLAGS += $(CODE_COVERAGE_CFLAGS)

21
config/always-compiler-options.m4
View File

@ -139,3 +139,24 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_UNUSED_BUT_SET_VARIABLE], [
CFLAGS="$saved_flags"
AC_SUBST([NO_UNUSED_BUT_SET_VARIABLE])
])
dnl #
dnl # Check if gcc supports -fno-omit-frame-pointer option.
dnl #
AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_OMIT_FRAME_POINTER], [
AC_MSG_CHECKING([whether $CC supports -fno-omit-frame-pointer])
saved_flags="$CFLAGS"
CFLAGS="$CFLAGS -fno-omit-frame-pointer"
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])], [
NO_OMIT_FRAME_POINTER=-fno-omit-frame-pointer
AC_MSG_RESULT([yes])
], [
NO_OMIT_FRAME_POINTER=
AC_MSG_RESULT([no])
])
CFLAGS="$saved_flags"
AC_SUBST([NO_OMIT_FRAME_POINTER])
])

1
config/zfs-build.m4
View File

@ -157,6 +157,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS], [
ZFS_AC_CONFIG_ALWAYS_CC_NO_BOOL_COMPARE
ZFS_AC_CONFIG_ALWAYS_CC_FRAME_LARGER_THAN
ZFS_AC_CONFIG_ALWAYS_CC_NO_FORMAT_TRUNCATION
ZFS_AC_CONFIG_ALWAYS_CC_NO_OMIT_FRAME_POINTER
ZFS_AC_CONFIG_ALWAYS_CC_ASAN
ZFS_AC_CONFIG_ALWAYS_TOOLCHAIN_SIMD
ZFS_AC_CONFIG_ALWAYS_ARCH