eclass/cros-llvm.eclass

# Copyright 2017 The ChromiumOS Authors
# Distributed under the terms of the GNU General Public License v2.

# @ECLASS: cros-llvm.eclass
# @MAINTAINER:
# ChromeOS toolchain team.<chromeos-toolchain@google.com>

# @DESCRIPTION:
# Functions to set the right toolchains and install prefix for llvm
# related libraries in crossdev stages.

inherit multilib

IUSE="continue-on-patch-failure python_targets_python3_6"

BDEPEND="python_targets_python3_6? ( dev-python/dataclasses )"
if [[ ${CATEGORY} == cross-* ]] ; then
	DEPEND="
		${CATEGORY}/binutils
		sys-devel/llvm
		"
fi

export CBUILD=${CBUILD:-${CHOST}}
export CTARGET=${CTARGET:-${CHOST}}

if [[ "${CTARGET}" = "${CHOST}" ]] ; then
	if [[ "${CATEGORY/cross-}" != "${CATEGORY}" ]] ; then
		export CTARGET=${CATEGORY/cross-}
	fi
fi

setup_cross_toolchain() {
	export CC="${CBUILD}-clang"
	export CXX="${CBUILD}-clang++"
	export PREFIX="/usr"

	if [[ ${CATEGORY} == cross-* ]] ; then
		export CC="${CTARGET}-clang"
		export CXX="${CTARGET}-clang++"
		export PREFIX="/usr/${CTARGET}/usr"
		export AS="$(tc-getAS "${CTARGET}")"
		export STRIP="$(tc-getSTRIP "${CTARGET}")"
		export OBJCOPY="$(tc-getOBJCOPY "${CTARGET}")"
	elif [[ "${CTARGET}" != "${CBUILD}" ]] ; then
		export CC="${CTARGET}-clang"
		export CXX="${CTARGET}-clang++"
	fi
	unset ABI MULTILIB_ABIS DEFAULT_ABI
	multilib_env "${CTARGET}"
}

# @FUNCTION: prepare_patches
# @USAGE: <SVN Revision>
# @DESCRIPTION:
# Applies the LLVM patches to the LLVM source at `$S`. If the SVN revision
# is not passed in, then it will be extracted from the `$PV` for non-9999 /
# non-llvm-{next,tot} ebuilds. Otherwise it will inspect the .git directory
# to compute the SVN revision.
prepare_patches() {
	local failure_mode
	failure_mode="$(usex continue-on-patch-failure continue fail)"

	local revision
	if [[ $# -ge 1 ]]; then
		revision="$1"
	else
		revision="$(cros-llvm_get_most_recent_revision)"
	fi

	"${FILESDIR}"/patch_manager/patch_manager.py \
		--svn_version "${revision}" \
		--patch_metadata_file "${FILESDIR}"/PATCHES.json \
		--failure_mode "${failure_mode}" \
		--src_path "${S}" || die
}

# @FUNCTION cros-llvm_get_most_recent_revision
# @USAGE: <optional LLVM directory>
# @DESCRIPTION:
# Returns the revision number (e.g., 12345) for the currently checked out LLVM
# revision. Respects the result of running `cros-llvm_default_preclone_hook`, if
# its been run, and caches the result for future use.
#
# shellcheck disable=SC2120
cros-llvm_get_most_recent_revision() {
	# b/293822345 - Don't depend on the .git repo for versioned builds.
	if [[ "${PV}" != "9999" ]]; then
		# 17.0_pre496208 -> 496208
		ver_cut 4
		return
	fi

	if [[ -f "${T}/llvm-rev" ]]; then
		# If this file exists, it was set by the unpack stage.
		cat "${T}/llvm-rev"
		return
	fi

	local subdir="${1:-"${S}/llvm"}"
	# Tries to get the revision ID of the most recent commit
	local rev current_git_head
	current_git_head="$(git -C "${subdir}" rev-parse HEAD)" || die
	rev="$("${FILESDIR}"/patch_manager/git_llvm_rev.py --llvm_dir "${subdir}" --sha="${current_git_head}")" || die "failed to get most recent llvm revision from ${subdir}"
	rev="$(cut -d 'r' -f 2 <<< "${rev}")"
	echo "${rev}" > "${T}/llvm-rev"
	echo "${rev}"
}

is_baremetal_abi() {
	# ABIs like armv7m-cros-eabi or arm-none-eabi.
	if [[ "${CTARGET}" == *-eabi ]]; then
		return 0
	fi
	return 1
}

# @FUNCTION cros-llvm_default_preclone_hook
# @DESCRIPTION:
# A function that takes in a global variable "path", to determine the
# location of the llvm-project git, and writes it to a tempfile ${T}/llvm-rev.
# This is useful when we need to get the svn revision number but we don't
# have access to this information from the ebuild itself.
#
# Used for cros-workon live ebuild support (PV=9999).
cros-llvm_default_preclone_hook() {
	# "path" is defined as a global in the cros-workon.eclass
	# shellcheck disable=SC2154
	local project_path="${path[0]}"
	if [[ -d "${project_path}" ]]; then
		# Note that cros-llvm_get_most_recent_revision caches its
		# result, so discarding the result here is fine.
		cros-llvm_get_most_recent_revision "${project_path}" > /dev/null
	fi
}

# @FUNCTION _cros-llvm_ensure_patches_stamp_exists
# @DESCRIPTION:
# Dies with an informative error message if the `patches_applied` stamp doesn't
# exist for the current package.
_cros-llvm_ensure_patches_stamp_exists() {
	local f="${S}/.ebuild/stamps/patches_applied/${CATEGORY}/${PN}"
	[[ -e "${f}" ]] || \
		die "No patches-applied stamp found at ${f}. Did you run src/third_party/toolchain-utils/llvm_tools/setup_for_workon.py?"
}

# @FUNCTION _cros-llvm_apply_patch_manager_patches
# @DESCRIPTION:
# Runs `patch_manager` to apply patches.
_cros-llvm_apply_patch_manager_patches() {
	local failure_mode
	failure_mode="$(usex continue-on-patch-failure continue fail)"
	"${FILESDIR}/patch_manager/patch_manager.py" \
		--svn_version="$(cros-llvm_get_most_recent_revision)" \
		--patch_metadata_file="${FILESDIR}/PATCHES.json" \
		--failure_mode="${failure_mode}" \
		--src_path="${S}" || die
}

# @FUNCTION cros-llvm_ensure_patches_applied
# @DESCRIPTION:
# Ensures that patches are applied, by either applying them (in non-9999
# ebuilds), or checking for a stamp that verifies that the patches were applied
# (in 9999 ebuilds).
cros-llvm_ensure_patches_applied() {
	if [[ "${PV}" == "9999" ]]; then
		# Use live sources if we're using the cros-workon ebuild. In
		# this case, patches must already be applied.
		_cros-llvm_ensure_patches_stamp_exists
	else
		_cros-llvm_apply_patch_manager_patches
	fi
}