#!/usr/bin/sh

# This is a script to select which GCC spec file fragment

# should be the destination of the redhat-annobin-cc1 symlink.

# Author: Nick Clifton  <nickc@redhat.com>

# Copyright (c) 2021 Red Hat.

#

# This is free software; you can redistribute it and/or modify it

# under the terms of the GNU General Public License as published

# by the Free Software Foundation; either version 2, or (at your

# option) any later version.

# It is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# Usage:

#   redhat-annobin-plugin-select [script-dir]

#

# If script-dir is not provided then /usr/lib/rpm/redhat is used

# as the location where all of the annobin plugin selection files

# can be found.

if test "x$1" = "x" ;

then

    rrcdir=/usr/lib/rpm/redhat

else

    rrcdir=$1

fi

# Set this variable to non-zero to enable the generation of debugging

# messages.

debug=0

# Decide which version of the annobin plugin for gcc should be used.

# There are two possible versions, one created by the annobin package and one

# created by the gcc package.  The logic selects the gcc version unless both

# have been built by the same version of the compiler.  In that case the

# annobin version is selected instead.

#

# The point of all this is that the annobin plugin is very sensitive to

# mismatches with the version of gcc that built it.  If the plugin is built

# by version A of gcc, but then run on version B of gcc, it is possible for

# the plugin to misbehave, which then causes problems if gating tests examine

# the plugin's output.  (This has happened more than once in RHEL...).

#

# So the plugin is built both by gcc and by the annobin package.  This means

# that whenever gcc is updated a fresh plugin is built, and the logic below

# will select that version.  But in order to allow annobin development to

# proceed independtently of gcc, the annobin package can also update its

# version of the plugin, and the logic will select this new version.

# This is where the annobin package stores the information on the version

# of gcc that built the annobin plugin.

aver=`gcc --print-file-name=plugin`/annobin-plugin-version-info

# This is where the gcc package stores its version information.

gver=`gcc --print-file-name=rpmver`

aplugin=`gcc --print-file-name=plugin`/annobin.so.0.0.0

gplugin=`gcc --print-file-name=plugin`/gcc-annobin.so.0.0.0

# This is the file that needs to be updated when either of those version

# files changes.

rac1=redhat-annobin-cc1

# This is the GCC spec file fragment that selects the gcc-built version of

# the annobin plugin

select_gcc=redhat-annobin-select-gcc-built-plugin

# This is the GCC spec file fragment that selects the annobin-built version

# of the annobin plugin

select_annobin=redhat-annobin-select-annobin-built-plugin

install_annobin_version=0

install_gcc_version=0

if [ -f $aplugin ]

then

    if [ -f $gplugin ]

    then

	if [ $debug -eq 1 ]

	then

	    echo "  redhat-rpm-config: Both plugins exist, checking version information"

	fi

	if [ -f $gver ]

	then

	    if [ -f $aver ]

	    then

		if [ $debug -eq 1 ]

		then

		    echo "  redhat-rpm-config: Both plugin version files exist - comparing..."

		fi

		# Get the first line from the version info files.  This is just in

		# vase there are extra lines in the files.

		avers=`head --lines=1 $aver`

		gvers=`head --lines=1 $gver`

		if [ $debug -eq 1 ]

		then

		    echo "  redhat-rpm-config: Annobin plugin built by gcc $avers"

		    echo "  redhat-rpm-config: GCC     plugin built by gcc $gvers"

		fi

		# If both plugins were built by the same version of gcc then select

		# the one from the annobin package (in case it is built from newer

		# sources).  If the plugin builder versions differ, select the gcc

		# built version instead.  This assumes that the gcc built version

		# always matches the installed gcc, which should be true.

		if [ $avers = $gvers ]

		then

		    if [ $debug -eq 1 ]

		    then

			echo "  redhat-rpm-config: Both plugins built by the same compiler - using annobin-built plugin"

		    fi

		    install_annobin_version=1

		else

		    if [ $debug -eq 1 ]

		    then

			echo "  redhat-rpm-config: Versions differ - using gcc-built plugin"

		    fi

		    install_gcc_version=1

		fi

	    else

		if [ $debug -eq 1 ]

		then

		    echo "  redhat-rpm-config: Annobin version file does not exist, using gcc-built plugin"

		fi

		install_gcc_version=1

	    fi

	else

	    if [ -f $aver ]

	    then

		# FIXME: This is suspicious.  If the installed GCC does not supports plugins

		# then enabling the annobin plugin will not work.

		if [ $debug -eq 1 ]

		then

		    echo "  redhat-rpm-config: GCC plugin version file does not exist, using annobin-built plugin"

		fi

		install_annobin_version=1

	    else

		if [ $debug -eq 1 ]

		then

		    echo "  redhat-rpm-config: Neither version file exists - playing safe and using gcc-built plugin"

		    echo "  redhat-rpm-config: Note: expected to find $aver and/or $gver"

		fi

		install_gcc_version=1

	    fi

	fi

    else

	if [ $debug -eq 1 ]

	then

	    echo "  redhat-rpm-config: Only the annobin plugin exists - using that"

	fi

	install_annobin_version=1

    fi

else

    if [ -f $gplugin ]

    then

	if [ $debug -eq 1 ]

	then

	    echo "  redhat-rpm-config: Only the gcc plugin exists - using that"

	fi

    else

	if [ $debug -eq 1 ]

	then

	    echo "  redhat-rpm-config: Neither plugin exists - playing safe and using gcc-built plugin"

	    echo "  redhat-rpm-config: Note: expected to find $aplugin and/or $gplugin"

	fi

    fi

    install_gcc_version=1

fi

if [ $install_annobin_version -eq 1 ]

then

    if [ $debug -eq 1 ]

    then

	echo "  redhat-rpm-config: Installing annobin version of $rac1"

    fi

    pushd $rrcdir > /dev/null

    rm -f $rac1

    ln -s $select_annobin "$rac1"

    popd > /dev/null

else if [ $install_gcc_version -eq 1 ]

     then

	if [ $debug -eq 1 ]

	then

	    echo "  redhat-rpm-config: Installing gcc version of $rac1"

	fi

	pushd $rrcdir > /dev/null

	rm -f $rac1

	ln -s $select_gcc $rac1

	popd > /dev/null

     fi

fi