From: Sebastien GODARD <sysstat@users.noreply.github.com>
Date: Sat, 30 Jan 2021 17:26:11 +0000 (+0100)
Subject: Add Link Time Optimization (LTO) support
X-Git-Tag: v12.5.3~9^2~1
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=8292f9047cdfb503094db7ad5630514fa42d4b86;p=sysstat

Add Link Time Optimization (LTO) support

Add new configuration option (--enable-lto) to make it possible to
compile sysstat with link time optimizations.

Signed-off-by: Sebastien GODARD <sysstat@users.noreply.github.com>
---

diff --git a/Makefile.in b/Makefile.in
index d110e4a..30eb926 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -160,6 +160,19 @@ ifdef REQUIRE_NLS
 	DFLAGS += $(REQUIRE_NLS)
 endif
 
+ifndef LTO
+LTO = @LTO@
+endif
+ifndef GCC_AR
+GCC_AR = @GCC_AR@
+endif
+ifeq ($(LTO),y)
+AR = $(GCC_AR)
+CFLAGS += -flto
+LD = gcc
+LDFLAGS += $(CFLAGS)
+endif
+
 ifndef INSTALL_CRON
 INSTALL_CRON = @INSTALL_CRON@
 endif
diff --git a/build/lto b/build/lto
new file mode 100644
index 0000000..8cba628
--- /dev/null
+++ b/build/lto
@@ -0,0 +1,7 @@
+
+Link Time Optimization (LTO) gives the compiler the opportunity to optimize
+as a single module all the different compilation units that make up a single
+executable. The downside is an increased compile time.
+Answer y to compile sysstat commands with link time optimizations.
+The default answer is n (no).
+
diff --git a/configure b/configure
index 9617e10..5a8194c 100755
--- a/configure
+++ b/configure
@@ -651,6 +651,8 @@ COMPRESSAFTER
 compressafter
 HISTORY
 history
+LTO
+GCC_AR
 NLS
 LFINTL
 SYSCONFIG_FILE
@@ -757,6 +759,7 @@ enable_pcp
 enable_sensors
 enable_largefile
 enable_nls
+enable_lto
 enable_file_attr
 enable_compress_manpg
 enable_clean_sa_dir
@@ -1403,6 +1406,7 @@ Optional Features:
   --disable-sensors       disable sensors support
   --disable-largefile     omit support for large files
   --disable-nls           disable National Language Support
+  --enable-lto            enable Link Time Optimization
   --disable-file-attr     do not set attributes on files being installed
   --disable-compress-manpg
                           do not compress sysstat manual pages
@@ -5107,6 +5111,7 @@ echo .
 #  --disable-stripping      do not strip object files
 #  --enable-copy-only       only copy files when installing sysstat
 #  --enable-use-crond       use standard cron daemon
+#  --enable-lto	            compile with Link Time Optimizations
 #
 # Some influential environment variables:
 #  rcdir         directory where startup scripts are installed
@@ -5370,6 +5375,66 @@ if test $NLS = "y" && test $LACKING_GETTEXT = "y"; then
 fi
 
 
+# Link Time Optimization
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking Link Time Optimization support" >&5
+$as_echo_n "checking Link Time Optimization support... " >&6; }
+# Check whether --enable-lto was given.
+if test "${enable_lto+set}" = set; then :
+  enableval=$enable_lto; AUX_LTO=$enableval
+else
+  AUX_LTO=no
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $AUX_LTO" >&5
+$as_echo "$AUX_LTO" >&6; }
+LTO="n"
+if test $AUX_LTO = "yes"; then
+	# Extract the first word of "gcc-ar", so it can be a program name with args.
+set dummy gcc-ar; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_GCC_AR+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$GCC_AR"; then
+  ac_cv_prog_GCC_AR="$GCC_AR" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_GCC_AR="gcc-ar"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+GCC_AR=$ac_cv_prog_GCC_AR
+if test -n "$GCC_AR"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $GCC_AR" >&5
+$as_echo "$GCC_AR" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+	if test x$GCC_AR != x"gcc-ar"; then
+		echo "WARNING: gcc-ar command not found! Disabling LTO support"
+		AUX_LTO="no"
+	else
+		LTO="y"
+	fi
+fi
+
+
 # Data history to keep by sa2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking number of daily data files to keep" >&5
 $as_echo_n "checking number of daily data files to keep... " >&6; }
diff --git a/configure.in b/configure.in
index efe7978..ffa303b 100644
--- a/configure.in
+++ b/configure.in
@@ -244,6 +244,7 @@ echo .
 #  --disable-stripping      do not strip object files
 #  --enable-copy-only       only copy files when installing sysstat
 #  --enable-use-crond       use standard cron daemon
+#  --enable-lto	            compile with Link Time Optimizations
 #
 # Some influential environment variables:
 #  rcdir         directory where startup scripts are installed
@@ -451,6 +452,25 @@ if test $NLS = "y" && test $LACKING_GETTEXT = "y"; then
 fi
 AC_SUBST(NLS)
 
+# Link Time Optimization
+AC_MSG_CHECKING(Link Time Optimization support)
+AC_ARG_ENABLE(lto,
+	      AC_HELP_STRING([--enable-lto],
+			     [enable Link Time Optimization]),
+			     AUX_LTO=$enableval,AUX_LTO=no)
+AC_MSG_RESULT($AUX_LTO)
+LTO="n"
+if test $AUX_LTO = "yes"; then
+	AC_CHECK_PROG(GCC_AR, gcc-ar, gcc-ar)
+	if test x$GCC_AR != x"gcc-ar"; then
+		echo "WARNING: gcc-ar command not found! Disabling LTO support"
+		AUX_LTO="no"
+	else
+		LTO="y"
+	fi
+fi
+AC_SUBST(LTO)
+
 # Data history to keep by sa2
 AC_MSG_CHECKING(number of daily data files to keep)
 AC_ARG_VAR([history],[number of daily data files to keep (default value is 7)]) 
diff --git a/do_test b/do_test
index 8b20579..d09db3e 100755
--- a/do_test
+++ b/do_test
@@ -3,6 +3,10 @@ if [ "$1" = "conf" ]
 then
 	make distclean
 	./configure sa_lib_dir=. sar_dir=. conf_dir=. conf_file=sysstat.sysconfig sa_dir=tests --enable-debuginfo
+elif [ "$1" = "conflto" ]
+then
+	make distclean
+	./configure sa_lib_dir=. sar_dir=. conf_dir=. conf_file=sysstat.sysconfig sa_dir=tests --enable-debuginfo --enable-lto
 elif [ "$1" = "comp" ]
 then
 	make TFLAGS="-DTEST"
diff --git a/iconfig b/iconfig
index 52b71c9..23afaf3 100755
--- a/iconfig
+++ b/iconfig
@@ -64,6 +64,15 @@ else
 	echo "Parameter --disable-nls is NOT set"
 fi
 
+# Link Time Optimization support
+LTO=`${ASK} 'Compile with Link Time Optimizations (LTO)? (y/n)' "--enable-lto" "lto"`
+if [ "${LTO}" = "y" ]; then
+	LTO="--enable-lto "
+else
+	LTO=""
+	echo "Parameter --enable-lto is NOT set"
+fi
+
 # Sensors support
 SENSORS=`${ASK} 'Disable sensors support? (y/n)' "--disable-sensors" "sensors"`
 if [ "${SENSORS}" = "y" ]; then
@@ -228,7 +237,7 @@ fi
 
 echo
 echo -n "./configure ${PREFIX}${SA_LIB_DIR}${SA_DIR}${SYSCONFIG_DIR}${SYSCONFIG_FILE} \
-${CLEAN_SA_DIR}${NLS}${HISTORY}${DELAY_RANGE}${COMPRESSAFTER}${MAN}${IGNORE_FILE_ATTR} \
+${CLEAN_SA_DIR}${NLS}${LTO}${HISTORY}${DELAY_RANGE}${COMPRESSAFTER}${MAN}${IGNORE_FILE_ATTR} \
 ${CRON}${USE_CROND}${RCDIR}"
 if [ "${SADC_OPT}" != "" ];
 then
@@ -238,7 +247,7 @@ echo "${COMPRESSMANPG}${INSTALL_DOC}${DEBUGINFO}${SENSORS}${PCP}${STRIP}${COPY_O
 echo
 
 ./configure ${PREFIX}${SA_LIB_DIR}${SA_DIR}${SYSCONFIG_DIR}${SYSCONFIG_FILE} \
-${CLEAN_SA_DIR}${NLS} \
+${CLEAN_SA_DIR}${NLS}${LTO} \
 ${HISTORY}${DELAY_RANGE}${COMPRESSAFTER}${MAN}${IGNORE_FILE_ATTR}${CRON}${USE_CROND}${RCDIR} \
 sadc_options="${SADC_OPT}" ${COMPRESSMANPG}${INSTALL_DOC}${DEBUGINFO}${SENSORS} \
 ${PCP}${STRIP}${COPY_ONLY}