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authorRich Felker <dalias@aerifal.cx>2013-07-22 21:22:04 -0400
committerRich Felker <dalias@aerifal.cx>2013-07-22 21:22:04 -0400
commita80847d86a8865a78fdbebe7f9e2533f7a74e010 (patch)
treeff2be203dab4c0d1b95e7d24b33be2a3696adb49
parent9578f0530ae9eebfc9928b76f8ab2972131c2dac (diff)
downloadmusl-a80847d86a8865a78fdbebe7f9e2533f7a74e010.tar.gz
enhance build process to allow selective -O3 optimization
the motivation for this patch is that the vast majority of libc is code that does not benefit at all from optimizations, but that certain components like string/memory operations can be major performance bottlenecks. at the same time, the old -falign-*=1 options are removed, since they were only beneficial for avoiding bloat when global -O3 was used, and in that case, they may have prevented some of the performance gains. to be the most useful, this patch will need further tuning. in particular, research is needed to determine which components should be built with -O3 by default, and it may be desirable to remove the hard-coded -O3 and instead allow more customization of the optimization level used for selected modules.
-rw-r--r--Makefile3
-rwxr-xr-xconfigure66
2 files changed, 57 insertions, 12 deletions
diff --git a/Makefile b/Makefile
index b9b78078..2cd2342a 100644
--- a/Makefile
+++ b/Makefile
@@ -80,6 +80,9 @@ include/bits/alltypes.h: include/bits/alltypes.h.in include/alltypes.h.in tools/
src/ldso/dynlink.lo: arch/$(ARCH)/reloc.h
+OPTIMIZE_SRCS = $(wildcard $(OPTIMIZE_GLOBS:%=src/%))
+$(OPTIMIZE_SRCS:%.c=%.o) $(OPTIMIZE_SRCS:%.c=%.lo): CFLAGS += -O3
+
%.o: $(ARCH)/%.s
$(CC) $(CFLAGS_ALL_STATIC) -c -o $@ $<
diff --git a/configure b/configure
index b679986f..327863c8 100755
--- a/configure
+++ b/configure
@@ -24,6 +24,7 @@ System types:
--host=HOST same as --target
Optional features:
+ --enable-optimize=... optimize listed components for speed over size [auto]
--enable-debug build with debugging information [disabled]
--enable-warnings build with recommended warnings flags [disabled]
--enable-gcc-wrapper build musl-gcc toolchain wrapper [auto]
@@ -104,6 +105,7 @@ fi
CFLAGS_C99FSE=
CFLAGS_AUTO=
LDFLAGS_AUTO=
+OPTIMIZE_GLOBS=
prefix=/usr/local/musl
exec_prefix='$(prefix)'
bindir='$(exec_prefix)/bin'
@@ -111,6 +113,7 @@ libdir='$(prefix)/lib'
includedir='$(prefix)/include'
syslibdir='/lib'
target=
+optimize=auto
debug=no
warnings=no
shared=yes
@@ -129,6 +132,9 @@ case "$arg" in
--disable-shared|--enable-shared=no) shared=no ;;
--enable-static|--enable-static=yes) static=yes ;;
--disable-static|--enable-static=no) static=no ;;
+--enable-optimize) optimize=yes ;;
+--enable-optimize=*) optimize=${arg#*=} ;;
+--disable-optimize) optimize=no ;;
--enable-debug|--enable-debug=yes) debug=yes ;;
--disable-debug|--enable-debug=no) debug=no ;;
--enable-warnings|--enable-warnings=yes) warnings=yes ;;
@@ -230,14 +236,57 @@ tryflag CFLAGS_C99FSE -fexcess-precision=standard \
|| { test "$ARCH" = i386 && tryflag CFLAGS_C99FSE -ffloat-store ; }
tryflag CFLAGS_C99FSE -frounding-math
+
+#
+# If debugging is explicitly enabled, don't auto-enable optimizations
+#
+if test "$debug" = yes ; then
+CFLAGS_AUTO=-g
+test "$optimize" = auto && optimize=no
+fi
+
#
-# Setup basic default CFLAGS: debug, optimization, and -pipe
+# Possibly add a -O option to CFLAGS and select modules to optimize with
+# -O3 based on the status of --enable-optimize and provided CFLAGS.
#
-if fnmatch '-O*|*\ -O*' "$CFLAGS_AUTO $CFLAGS" ; then :
+printf "checking for optimization settings... "
+case "x$optimize" in
+xauto)
+if fnmatch '-O*|*\ -O*' "$CFLAGS_AUTO $CFLAGS" ; then
+printf "using provided CFLAGS\n" ;optimize=no
else
-tryflag CFLAGS_AUTO -Os || tryflag CFLAGS_AUTO -O2
+printf "using defaults\n" ; optimize=yes
fi
-test "x$debug" = xyes && CFLAGS_AUTO="-g"
+;;
+xsize|xnone) printf "minimize size\n" ; optimize=size ;;
+xno|x) printf "disabled\n" ; optimize=no ;;
+*) printf "custom\n" ;;
+esac
+
+test "$optimize" = no || tryflag CFLAGS_AUTO -Os || tryflag CFLAGS_AUTO -O2
+test "$optimize" = yes && optimize="internal,malloc,math,string"
+
+if fnmatch 'no|size' "$optimize" ; then :
+else
+printf "components to be optimized for speed:"
+while test "$optimize" ; do
+case "$optimize" in
+*,*) this=${optimize%%,*} optimize=${optimize#*,} ;;
+*) this=$optimize optimize=
+esac
+printf " $this"
+case "$this" in
+*/*.c) ;;
+*/*) this=$this*.c ;;
+*) this=$this/*.c ;;
+esac
+OPTIMIZE_GLOBS="$OPTIMIZE_GLOBS $this"
+done
+OPTIMIZE_GLOBS=${OPTIMIZE_GLOBS# }
+printf "\n"
+fi
+
+# Always try -pipe
tryflag CFLAGS_AUTO -pipe
#
@@ -267,14 +316,6 @@ tryflag CFLAGS_AUTO -fno-asynchronous-unwind-tables
tryflag CFLAGS_AUTO -Wa,--noexecstack
#
-# Some optimization levels add bloated alignment that hurt performance
-#
-tryflag CFLAGS_AUTO -falign-functions=1
-tryflag CFLAGS_AUTO -falign-labels=1
-tryflag CFLAGS_AUTO -falign-loops=1
-tryflag CFLAGS_AUTO -falign-jumps=1
-
-#
# On x86, make sure we don't have incompatible instruction set
# extensions enabled by default. This is bad for making static binaries.
# We cheat and use i486 rather than i386 because i386 really does not
@@ -366,6 +407,7 @@ CPPFLAGS = $CPPFLAGS
LDFLAGS = $LDFLAGS_AUTO $LDFLAGS
CROSS_COMPILE = $CROSS_COMPILE
LIBCC = $LIBCC
+OPTIMIZE_GLOBS = $OPTIMIZE_GLOBS
EOF
test "x$static" = xno && echo "STATIC_LIBS ="
test "x$shared" = xno && echo "SHARED_LIBS ="