[patch] Patch to enable building GCC itself with LTO

0001-sys-devel-gcc-dev-lang-gnat-gpl-add-a-USE-for-buildi.patch (text/plain), 2.88 KB, created by Shane Peelar on 2019-05-11 15:53:45 UTC

From 71f3b837fbf6f7b215857fd3830e4c353d7127b6 Mon Sep 17 00:00:00 2001
From: Shane Peelar <[e-mail]>
Date: Wed, 8 May 2019 14:55:53 -0400
Subject: [PATCH] {sys-devel/gcc,dev-lang/gnat-gpl}: add a USE for building GCC
 with LTO

Signed-off-by: Shane Peelar <[e-mail]>
---
 dev-lang/gnat-gpl/metadata.xml | 1 +
 eclass/toolchain.eclass        | 6 ++++++
 sys-devel/gcc/metadata.xml     | 1 +
 3 files changed, 8 insertions(+)

diff --git a/dev-lang/gnat-gpl/metadata.xml b/dev-lang/gnat-gpl/metadata.xml
index 1e906679715..18d872644b9 100644
--- a/dev-lang/gnat-gpl/metadata.xml
+++ b/dev-lang/gnat-gpl/metadata.xml
@@ -18,6 +18,7 @@
 		<flag name="libssp">Build SSP support into a dedicated library rather
 			than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T
 			KNOW WHAT IT DOES)</flag>
+		<flag name="lto">Build using Link Time Optimizations (LTO)</flag>
 		<flag name="nopie">Disable PIE support (NOT FOR GENERAL USE)</flag>
 		<flag name="nossp">Disable SSP support (NOT FOR GENERAL USE)</flag>
 		<flag name="objc">Build support for the Objective C code language
diff --git a/eclass/toolchain.eclass b/eclass/toolchain.eclass
index 17850db4304..db50d2c4343 100644
--- a/eclass/toolchain.eclass
+++ b/eclass/toolchain.eclass
@@ -159,6 +159,7 @@ if [[ ${PN} != "kgcc64" && ${PN} != gcc-* ]] ; then
 	tc_version_is_at_least 4.1 && IUSE+=" libssp objc++"
 	tc_version_is_at_least 4.2 && IUSE+=" +openmp"
 	tc_version_is_at_least 4.3 && IUSE+=" fixed-point"
+	tc_version_is_at_least 4.4 && IUSE+=" lto"
 	tc_version_is_at_least 4.7 && IUSE+=" go"
 	# Note: while <=gcc-4.7 also supported graphite, it required forked ppl
 	# versions which we dropped.  Since graphite was also experimental in
@@ -993,6 +994,11 @@ toolchain_src_configure() {
 		confgcc+=( --enable-libstdcxx-time )
 	fi
 
+	# Build compiler using LTO
+	if tc_version_is_at_least 4.4 && use_if_iuse lto ; then
+		confgcc+=( --with-build-config=bootstrap-lto )
+	fi
+
 	# Support to disable pch when building libstdcxx
 	if tc_version_is_at_least 6.0 && ! use_if_iuse pch ; then
 		confgcc+=( --disable-libstdcxx-pch )
diff --git a/sys-devel/gcc/metadata.xml b/sys-devel/gcc/metadata.xml
index d70e7213148..1b47b03d910 100644
--- a/sys-devel/gcc/metadata.xml
+++ b/sys-devel/gcc/metadata.xml
@@ -21,6 +21,7 @@
       This will slow down the compiler a bit as it forces all of the toolchain to be shared libs.</flag>
     <flag name="libssp">Build SSP support into a dedicated library rather than use the
       code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)</flag>
+    <flag name="lto">Build using Link Time Optimizations (LTO)</flag>
     <flag name="mpx">Enable support for Intel Memory Protection Extensions (MPX)</flag>
     <flag name="mudflap">Add support for mudflap, a pointer use checking library</flag>
     <flag name="nopie">Disable PIE support (NOT FOR GENERAL USE)</flag>
-- 
2.21.0