[gentoo-dev] [PATCH 1/2] go-env.eclass: unify GOARCH mapping logic with dev-lang/go

[WANG Xuerui <xen0n@gentoo.org>]

Previously the eclass featured its own GOARCH mapping, that took care
of less cases than the dev-lang/go ebuild did, and broke Go packages on
arches like loong (GOARCH=loong64), mips (4 GOARCHes supported in total)
or riscv (GOARCH=riscv64).

This patch adds a copy of the go_arch() helper from dev-lang/go to the
eclass and switches the go-env_set_compile_environment() function to use
that, to fix the problem at hand.

Fixes: 878d04daaf34765e6224e58139a9c45921d7a0c3
Closes: https://bugs.gentoo.org/917750
Signed-off-by: WANG Xuerui <xen0n@gentoo.org>
---
 eclass/go-env.eclass | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/eclass/go-env.eclass b/eclass/go-env.eclass
index ba4f6c3fbb59..08e3cf498a70 100644
--- a/eclass/go-env.eclass
+++ b/eclass/go-env.eclass
@@ -8,7 +8,7 @@
 # Flatcar Linux Maintainers <infra@flatcar-linux.org>
 # @BLURB: Helper eclass for setting the Go compile environment. Required for cross-compiling.
 # @DESCRIPTION:
-# This eclass includes a helper function for setting the compile environment for Go ebuilds.
+# This eclass includes helper functions for setting the compile environment for Go ebuilds.
 # Intended to be called by other Go eclasses in an early build stage, e.g. src_unpack.
 
 if [[ -z ${_GO_ENV_ECLASS} ]]; then
@@ -25,24 +25,36 @@ inherit toolchain-funcs
 # (e.g. "emerge-aarch64-cross-linux-gnu foo" run on x86_64 will emerge "foo" for x86_64
 #  instead of aarch64)
 go-env_set_compile_environment() {
-	local arch="$(tc-arch)"
-	case "${arch}" in
-		x86)	GOARCH="386" ;;
-		x64-*)	GOARCH="amd64" ;;
-		ppc64)	if [[ "$(tc-endian)" == "big" ]] ; then
-					GOARCH="ppc64"
-				else
-					GOARCH="ppc64le"
-				fi ;;
-			*)	GOARCH="${arch}" ;;
-	esac
-
 	tc-export CC CXX
-	export GOARCH
+
+	export GOARCH="$(go-env_goarch)"
 	export CGO_CFLAGS="${CGO_CFLAGS:-$CFLAGS}"
 	export CGO_CPPFLAGS="${CGO_CPPFLAGS:-$CPPFLAGS}"
 	export CGO_CXXFLAGS="${CGO_CXXFLAGS:-$CXXFLAGS}"
 	export CGO_LDFLAGS="${CGO_LDFLAGS:-$LDFLAGS}"
 }
 
+# @FUNCTION: go-env_goarch
+# @USAGE: [toolchain prefix]
+# @DESCRIPTION:
+# Returns the appropriate GOARCH setting for the target architecture.
+go-env_goarch() {
+	# By chance most portage arch names match Go
+	local tc_arch=$(tc-arch $@)
+	case "${tc_arch}" in
+		x86)	echo 386;;
+		x64-*)	echo amd64;;
+		loong)	echo loong64;;
+		mips) if use abi_mips_o32; then
+				[[ $(tc-endian $@) = big ]] && echo mips || echo mipsle
+			elif use abi_mips_n64; then
+				[[ $(tc-endian $@) = big ]] && echo mips64 || echo mips64le
+			fi ;;
+		ppc64) [[ $(tc-endian $@) = big ]] && echo ppc64 || echo ppc64le ;;
+		riscv) echo riscv64 ;;
+		s390) echo s390x ;;
+		*)		echo "${tc_arch}";;
+	esac
+}
+
 fi
-- 
2.42.1