sys-devel/binutils: rework LTO handling

Get tests passing when LTO is used and rework USE=pgo handling while at it, as
it's interlinked with LTO b/c of the upstream infra for it.

This follows on from:
* 1764651a4f7daf8d622db7fddeea891809cab2fb
* f900949be85e2b2b21cd68b7f5163208d0429028
* f900949be85e2b2b21cd68b7f5163208d0429028
where I kept hitting misc issues where the build for the live ebuild failed
with LTO or otherwise.

With this, I only needed one patch to libctf's tests [0] which I've now
pinged upstream. (I also had an odd single gprofng failure I haven't looked at
yet.)

* For LTO + (tests || pgo), always filter '-Wa,*'. This is an unfortunate one,
  but the bootstrap test fails with it.

* USE=pgo no longer implies LTO. If -flto is being used, then we pass
  --enable-pgo-build=lto. If not, we pass --enable-pgo-build=yes.

* For USE=pgo, filter out LTO after we applied the build system configuration,
  because otherwise there's a risk we're going to break the tests used for profiling.

* In src_test, use a subshell to localise the filtering of flags we do.

* For tests, pass {C,CXX,LD}FLAGS_FOR_TARGET to make, as otherwise it'll use
  what it found from configure (and e.g. pick up LTO again -> many tests fail
  as they're not intended to be used with it).

[0] https://inbox.sourceware.org/binutils/87sf2evr35.fsf@esperi.org.uk/

Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 28 insertions, 4 deletions

diff --git a/sys-devel/binutils/binutils-9999.ebuild b/sys-devel/binutils/binutils-9999.ebuild
index 9169e3ca712c..9b30843ce94f 100644
--- a/sys-devel/binutils/binutils-9999.ebuild
+++ b/sys-devel/binutils/binutils-9999.ebuild
@@ -333,10 +333,20 @@ src_configure() {
 		)
 	fi
 
+	if use test || { use pgo && tc-is-lto ; } ; then
+		# -Wa,* needs to be consistent everywhere or lto-wrapper will complain
+		filter-flags '-Wa,*'
+	fi
+
 	if ! is_cross ; then
-		myconf+=( $(use_enable pgo pgo-build lto) )
+		myconf+=( $(use_enable pgo pgo-build $(tc-is-lto && echo "lto" || echo "yes")) )
 
 		if use pgo ; then
+			# We let configure handle it for us because it has to run
+			# the testsuite later on for profiling, and LTO isn't compatible
+			# with the testsuite.
+			filter-lto
+
 			export BUILD_CFLAGS="${CFLAGS}"
 		fi
 	fi
@@ -378,10 +388,24 @@ src_test() {
 	local -x XZ_OPT="-T1"
 	local -x XZ_DEFAULTS="-T1"
 
-	# bug #637066
-	filter-flags -Wall -Wreturn-type
+	(
+		# Tests don't expect LTO
+		filter-lto
 
-	emake -k check
+		# lto-wrapper warnings which confuse tests
+		filter-flags '-Wa,*'
+
+		# bug #637066
+		filter-flags -Wall -Wreturn-type
+
+		emake -k check \
+			CFLAGS_FOR_TARGET="${CFLAGS_FOR_TARGET:-${CFLAGS}}" \
+			CXXFLAGS_FOR_TARGET="${CXXFLAGS_FOR_TARGET:-${CXXFLAGS}}" \
+			LDFLAGS_FOR_TARGET="${LDFLAGS_FOR_TARGET:-${LDFLAGS}}" \
+			CFLAGS="${CFLAGS}" \
+			CXXFLAGS="${CXXFLAGS}" \
+			LDFLAGS="${LDFLAGS}"
+	)
 }
 
 src_install() {