eclass/go-env: Sync with Gentoo

It's from Gentoo commit 29f0721c4bc11ef3b9d94590016c25a190bc0f20.

sdk_container/src/third_party/portage-stable/eclass/go-env.eclass

@@ -1,48 +1,131 @@
-# Copyright 2023 Gentoo Authors
+# Copyright 2023-2024 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 # @ECLASS: go-env.eclass
 # @MAINTAINER:
-# Flatcar Maintainers <infra@flatcar.org>
+# Flatcar Linux Maintainers <infra@flatcar-linux.org>
 # @AUTHOR:
-# Flatcar Maintainers <infra@flatcar.org>
+# Flatcar Linux Maintainers <infra@flatcar-linux.org>
+# @SUPPORTED_EAPIS: 7 8
 # @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.
 
+case ${EAPI} in
+	7|8) ;;
+	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
+esac
+
 if [[ -z ${_GO_ENV_ECLASS} ]]; then
 _GO_ENV_ECLASS=1
 
-inherit toolchain-funcs
+inherit flag-o-matic toolchain-funcs
 
 # @FUNCTION: go-env_set_compile_environment
 # @DESCRIPTION:
 # Set up basic compile environment: CC, CXX, and GOARCH.
+# Necessary platform-specific settings such as GOARM or GO386 are also set
+# according to the Portage configuration when building for those architectures.
 # Also carry over CFLAGS, LDFLAGS and friends.
 # Required for cross-compiling with crossdev.
 # If not set, host defaults will be used and the resulting binaries are host arch.
 # (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=$(tc-arch "${CHOST}}")
+	tc-export CC CXX PKG_CONFIG
-	case "${arch}" in
+
-		x86)	GOARCH="386" ;;
+	export GOARCH="$(go-env_goarch)"
-		x64-*)	GOARCH="amd64" ;;
+	use arm && export GOARM=$(go-env_goarm)
-		ppc64)	if [[ "$(tc-endian "${${CHOST}}")" = "big" ]] ; then
+	use x86 && export GO386=$(go-env_go386)
-					GOARCH="ppc64"
+
-				else
+	# XXX: Hack for checking ICE (bug #912152, gcc PR113204)
-					GOARCH="ppc64le"
+	has_version -b "sys-devel/gcc[debug]" && filter-lto
-				fi ;;
-		*)	GOARCH="${arch}" ;;
-	esac
 
-	tc-export CC CXX
-	export 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_goos
+# @USAGE: [toolchain prefix]
+# @DESCRIPTION:
+# Returns the appropriate GOOS setting for the target operating system.
+go-env_goos() {
+	local target=${1:-${CHOST}}
+	case "${target}" in
+		*-linux*) echo linux ;;
+		*-darwin*) echo darwin ;;
+		*-freebsd*) echo freebsd ;;
+		*-netbsd*) echo netbsd ;;
+		*-openbsd*) echo openbsd ;;
+		*-solaris*) echo solaris ;;
+		*-cygwin*|*-interix*|*-winnt*) echo windows ;;
+		*) die "unknown GOOS for ${target}" ;;
+	esac
+}
+
+# @FUNCTION: go-env_goarch
+# @USAGE: [toolchain prefix]
+# @DESCRIPTION:
+# Returns the appropriate GOARCH setting for the target architecture.
+go-env_goarch() {
+	local target=${1:-${CHOST}}
+	# Some Portage arch names match Go.
+	local arch=$(tc-arch "${target}") cpu=${target%%-*}
+	case "${arch}" in
+		x86)	echo 386 ;;
+		loong)	echo loong64 ;;
+		*)		case "${cpu}" in
+					aarch64*be) echo arm64be ;;
+					arm64) echo arm64 ;;
+					arm*b*) echo armbe ;;
+					mips64*l*) echo mips64le ;;
+					mips*l*) echo mipsle ;;
+					powerpc64le*) echo ppc64le ;;
+					arm64|s390x) echo "${cpu}" ;;
+					mips64*|riscv64*|sparc64*) echo "${arch}64" ;;
+					*) echo "${arch}" ;;
+				esac ;;
+	esac
+}
+
+# @FUNCTION: go-env_go386
+# @DESCRIPTION:
+# Returns the appropriate GO386 setting for the CFLAGS in use.
+go-env_go386() {
+	# Piggy-back off any existing CPU_FLAGS_X86 usage in the ebuild if
+	# it's there.
+	if in_iuse cpu_flags_x86_sse2 && use cpu_flags_x86_sse2 ; then
+		echo 'sse2'
+		return
+	fi
+
+	if tc-cpp-is-true "defined(__SSE2__)" ${CFLAGS} ${CXXFLAGS} ; then
+		echo 'sse2'
+		return
+	fi
+
+	# Go 1.16 dropped explicit support for 386 FP and relies on software
+	# emulation instead in the absence of SSE2.
+	echo 'softfloat'
+}
+
+# @FUNCTION: go-env_goarm
+# @USAGE: [CHOST-value]
+# @DESCRIPTION:
+# Returns the appropriate GOARM setting for the CHOST given, or the default
+# CHOST.
+go-env_goarm() {
+	case "${1:-${CHOST}}" in
+		armv5*)	echo 5;;
+		armv6*)	echo 6;;
+		armv7*)	echo 7;;
+		*)
+			die "unknown GOARM for ${1:-${CHOST}}"
+			;;
+	esac
+}
+
 fi