#!/usr/bin/env bash
# Copyright 2009 The Go Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.

# See golang.org/s/go15bootstrap for an overview of the build process.

# Environment variables that control make.bash:
#
# GOROOT_FINAL: The expected final Go root, baked into binaries.
# The default is the location of the Go tree during the build.
#
# GOHOSTARCH: The architecture for host tools (compilers and
# binaries).  Binaries of this type must be executable on the current
# system, so the only common reason to set this is to set
# GOHOSTARCH=386 on an amd64 machine.
#
# GOARCH: The target architecture for installed packages and tools.
#
# GOOS: The target operating system for installed packages and tools.
#
# GO_GCFLAGS: Additional go tool compile arguments to use when
# building the packages and commands.
#
# GO_LDFLAGS: Additional go tool link arguments to use when
# building the commands.
#
# CGO_ENABLED: Controls cgo usage during the build. Set it to 1
# to include all cgo related files, .c and .go file with "cgo"
# build directive, in the build. Set it to 0 to ignore them.
#
# GO_EXTLINK_ENABLED: Set to 1 to invoke the host linker when building
# packages that use cgo.  Set to 0 to do all linking internally.  This
# controls the default behavior of the linker's -linkmode option.  The
# default value depends on the system.
#
# CC: Command line to run to compile C code for GOHOSTARCH.
# Default is "gcc". Also supported: "clang".
#
# CC_FOR_TARGET: Command line to run to compile C code for GOARCH.
# This is used by cgo.  Default is CC.
#
# CXX_FOR_TARGET: Command line to run to compile C++ code for GOARCH.
# This is used by cgo. Default is CXX, or, if that is not set, 
# "g++" or "clang++".
#
# GO_DISTFLAGS: extra flags to provide to "dist bootstrap". Use "-s"
# to build a statically linked toolchain.

set -e
if [ ! -f run.bash ]; then
	echo 'make.bash must be run from $GOROOT/src' 1>&2
	exit 1
fi

# Test for Windows.
case "$(uname)" in
*MINGW* | *WIN32* | *CYGWIN*)
	echo 'ERROR: Do not use make.bash to build on Windows.'
	echo 'Use make.bat instead.'
	echo
	exit 1
	;;
esac

# Test for bad ld.
if ld --version 2>&1 | grep 'gold.* 2\.20' >/dev/null; then
	echo 'ERROR: Your system has gold 2.20 installed.'
	echo 'This version is shipped by Ubuntu even though'
	echo 'it is known not to work on Ubuntu.'
	echo 'Binaries built with this linker are likely to fail in mysterious ways.'
	echo
	echo 'Run sudo apt-get remove binutils-gold.'
	echo
	exit 1
fi

# Test for bad SELinux.
# On Fedora 16 the selinux filesystem is mounted at /sys/fs/selinux,
# so loop through the possible selinux mount points.
for se_mount in /selinux /sys/fs/selinux
do
	if [ -d $se_mount -a -f $se_mount/booleans/allow_execstack -a -x /usr/sbin/selinuxenabled ] && /usr/sbin/selinuxenabled; then
		if ! cat $se_mount/booleans/allow_execstack | grep -c '^1 1$' >> /dev/null ; then
			echo "WARNING: the default SELinux policy on, at least, Fedora 12 breaks "
			echo "Go. You can enable the features that Go needs via the following "
			echo "command (as root):"
			echo "  # setsebool -P allow_execstack 1"
			echo
			echo "Note that this affects your system globally! "
			echo
			echo "The build will continue in five seconds in case we "
			echo "misdiagnosed the issue..."

			sleep 5
		fi
	fi
done

# Test for debian/kFreeBSD.
# cmd/dist will detect kFreeBSD as freebsd/$GOARCH, but we need to
# disable cgo manually.
if [ "$(uname -s)" == "GNU/kFreeBSD" ]; then
        export CGO_ENABLED=0
fi

# Clean old generated file that will cause problems in the build.
rm -f ./runtime/runtime_defs.go

# Finally!  Run the build.

echo '##### Building Go bootstrap tool.'
echo cmd/dist
export GOROOT="$(cd .. && pwd)"
GOROOT_BOOTSTRAP=${GOROOT_BOOTSTRAP:-$HOME/go1.4}
if [ ! -x "$GOROOT_BOOTSTRAP/bin/go" ]; then
	echo "ERROR: Cannot find $GOROOT_BOOTSTRAP/bin/go." >&2
	echo "Set \$GOROOT_BOOTSTRAP to a working Go tree >= Go 1.4." >&2
fi
rm -f cmd/dist/dist
GOROOT="$GOROOT_BOOTSTRAP" GOOS="" GOARCH="" "$GOROOT_BOOTSTRAP/bin/go" build -o cmd/dist/dist ./cmd/dist

# -e doesn't propagate out of eval, so check success by hand.
eval $(./cmd/dist/dist env -p || echo FAIL=true)
if [ "$FAIL" = true ]; then
	exit 1
fi

echo

if [ "$1" = "--dist-tool" ]; then
	# Stop after building dist tool.
	mkdir -p "$GOTOOLDIR"
	if [ "$2" != "" ]; then
		cp cmd/dist/dist "$2"
	fi
	mv cmd/dist/dist "$GOTOOLDIR"/dist
	exit 0
fi

buildall="-a"
if [ "$1" = "--no-clean" ]; then
	buildall=""
	shift
fi
./cmd/dist/dist bootstrap $buildall $GO_DISTFLAGS -v # builds go_bootstrap
# Delay move of dist tool to now, because bootstrap may clear tool directory.
mv cmd/dist/dist "$GOTOOLDIR"/dist
echo

if [ "$GOHOSTARCH" != "$GOARCH" -o "$GOHOSTOS" != "$GOOS" ]; then
	echo "##### Building packages and commands for host, $GOHOSTOS/$GOHOSTARCH."
	# CC_FOR_TARGET is recorded as the default compiler for the go tool. When building for the host, however,
	# use the host compiler, CC, from `cmd/dist/dist env` instead.
	CC=$CC GOOS=$GOHOSTOS GOARCH=$GOHOSTARCH \
		"$GOTOOLDIR"/go_bootstrap install -gcflags "$GO_GCFLAGS" -ldflags "$GO_LDFLAGS" -v std cmd
	echo
fi

echo "##### Building packages and commands for $GOOS/$GOARCH."
CC=$CC_FOR_TARGET "$GOTOOLDIR"/go_bootstrap install $GO_FLAGS -gcflags "$GO_GCFLAGS" -ldflags "$GO_LDFLAGS" -v std cmd
echo

rm -f "$GOTOOLDIR"/go_bootstrap

if [ "$1" != "--no-banner" ]; then
	"$GOTOOLDIR"/dist banner
fi
