[Python-checkins] cpython (merge 3.5 -> default): Issue #25702: A --with-lto configure option has been added that will
gregory.p.smith
python-checkins at python.org
Fri Apr 15 19:59:17 EDT 2016
https://hg.python.org/cpython/rev/3103af76f4c4
changeset: 101000:3103af76f4c4
parent: 100998:e3c6362cc139
parent: 100999:f16ec63055ad
user: Gregory P. Smith <greg at krypto.org>
date: Fri Apr 15 16:58:51 2016 -0700
summary:
Issue #25702: A --with-lto configure option has been added that will
enable link time optimizations at build time during a make profile-opt.
files:
Makefile.pre.in | 4 +-
Misc/NEWS | 6 ++++
configure | 46 +++++++++++++++++++++++++++++++++++++
configure.ac | 33 ++++++++++++++++++++++++++
4 files changed, 87 insertions(+), 2 deletions(-)
diff --git a/Makefile.pre.in b/Makefile.pre.in
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -504,7 +504,7 @@
$(MAKE) profile-removal
build_all_generate_profile:
- $(MAKE) all CFLAGS_NODIST="$(CFLAGS) $(PGO_PROF_GEN_FLAG)" LDFLAGS="$(LDFLAGS) $(PGO_PROF_GEN_FLAG)" LIBS="$(LIBS)"
+ $(MAKE) all CFLAGS_NODIST="$(CFLAGS) $(PGO_PROF_GEN_FLAG) @LTOFLAGS@" LDFLAGS="$(LDFLAGS) $(PGO_PROF_GEN_FLAG) @LTOFLAGS@" LIBS="$(LIBS)"
run_profile_task:
: # FIXME: can't run for a cross build
@@ -514,7 +514,7 @@
$(LLVM_PROF_MERGER)
build_all_use_profile:
- $(MAKE) all CFLAGS_NODIST="$(CFLAGS) $(PGO_PROF_USE_FLAG)"
+ $(MAKE) all CFLAGS_NODIST="$(CFLAGS) $(PGO_PROF_USE_FLAG) @LTOFLAGS@" LDFLAGS="$(LDFLAGS) @LTOFLAGS@"
# Compile and run with gcov
.PHONY=coverage coverage-lcov coverage-report
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -976,6 +976,12 @@
Build
-----
+- Issue #25702: A --with-lto configure option has been added that will
+ enable link time optimizations at build time during a make profile-opt.
+ Some compilers and toolchains are known to not produce stable code when
+ using LTO, be sure to test things thoroughly before relying on it.
+ It can provide a few % speed up over profile-opt alone.
+
- Issue #26624: Adds validation of ucrtbase[d].dll version with warning
for old versions.
diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -673,6 +673,7 @@
LLVM_PROF_MERGER
PGO_PROF_USE_FLAG
PGO_PROF_GEN_FLAG
+LTOFLAGS
ABIFLAGS
LN
MKDIR_P
@@ -807,6 +808,7 @@
enable_shared
enable_profiling
with_pydebug
+with_lto
with_hash_algorithm
with_address_sanitizer
with_libs
@@ -1487,6 +1489,8 @@
compiler
--with-suffix=.exe set executable suffix
--with-pydebug build with Py_DEBUG defined
+ --with-lto Enable Link Time Optimization in PGO builds.
+ Disabled by default.
--with-hash-algorithm=[fnv|siphash24]
select hash algorithm
--with-address-sanitizer
@@ -6560,6 +6564,48 @@
fi
+# Enable LTO flags
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-lto" >&5
+$as_echo_n "checking for --with-lto... " >&6; }
+
+# Check whether --with-lto was given.
+if test "${with_lto+set}" = set; then :
+ withval=$with_lto;
+if test "$withval" != no
+then
+ Py_LTO='true'
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; };
+else
+ Py_LTO='false'
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; };
+fi
+else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+if test "$Py_LTO" = 'true' ; then
+ case $CC in
+ *clang*)
+ # Any changes made here should be reflected in the GCC+Darwin case below
+ LTOFLAGS="-flto"
+ ;;
+ *gcc*)
+ case $ac_sys_system in
+ Darwin*)
+ LTOFLAGS="-flto"
+ ;;
+ *)
+ LTOFLAGS="-flto -fuse-linker-plugin -ffat-lto-objects -flto-partition=none"
+ ;;
+ esac
+ ;;
+ esac
+fi
+
# Enable PGO flags.
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -1235,6 +1235,39 @@
fi],
[AC_MSG_RESULT(no)])
+# Enable LTO flags
+AC_SUBST(LTOFLAGS)
+AC_MSG_CHECKING(for --with-lto)
+AC_ARG_WITH(lto, AS_HELP_STRING([--with-lto], [Enable Link Time Optimization in PGO builds. Disabled by default.]),
+[
+if test "$withval" != no
+then
+ Py_LTO='true'
+ AC_MSG_RESULT(yes);
+else
+ Py_LTO='false'
+ AC_MSG_RESULT(no);
+fi],
+[AC_MSG_RESULT(no)])
+if test "$Py_LTO" = 'true' ; then
+ case $CC in
+ *clang*)
+ # Any changes made here should be reflected in the GCC+Darwin case below
+ LTOFLAGS="-flto"
+ ;;
+ *gcc*)
+ case $ac_sys_system in
+ Darwin*)
+ LTOFLAGS="-flto"
+ ;;
+ *)
+ LTOFLAGS="-flto -fuse-linker-plugin -ffat-lto-objects -flto-partition=none"
+ ;;
+ esac
+ ;;
+ esac
+fi
+
# Enable PGO flags.
AC_SUBST(PGO_PROF_GEN_FLAG)
AC_SUBST(PGO_PROF_USE_FLAG)
--
Repository URL: https://hg.python.org/cpython
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