Hi Guys,
Attached is a fully working version of the "fat-gcc" script. This
version can now cope with multiple compilations at the same, C++ and
Assembler source files, and building shared libraries. It has only had
a small amount of local testing however, so if you do use and find a
bug, please let me know.
Cheers
Nick Clifton
#!/bin/bash
# This is a script to built "fat" ARM binaries that contain two separate
# sets of executable code, one using the soft-float API and one using
# the hard-float API.
#
# Copyright (c) Red Hat 2011
# Written by: Nick Clifton <nickc@xxxxxxxxxx>
# Released under the LGPL v3. See: http://www.gnu.org/licenses/lgpl.html
# For a description of the command line options supported by this script
# see the show_help() function.
#
# Note: if you are modifying this script to run in a new enviroment then
# you should only need to change the contents of the init_user() function.
#
# Note: the intention is that this script should be named "gcc" and
# placed in the execution path ahead of the real gcc. Then it can
# be used inside rpm build scripts and makefiles.
#
# Note: The latest version of this script can be found here:
# http://intranet.ges.redhat.com/arm-linux/
#
# To Do:
# * Add detection of already swapped binaries.
#
# * Detect alt API binaries that are the same as the original API binaries.
#
# * Support GCC switches that take an argument where that argument is
# provided as a second option, rather than after an equals sign.
#----------------------------------------------------------------
# Initialise user modifiable global variables.
init_user ()
{
# The command line switch(es) to add to the end of a compilation
# in order to generate the alternative API:
ALT_API="-mfloat-abi=hard"
# The prefix of the section name that is inserted into a binary
# that contains the alternative API code:
ALT_PREFIX=".note.alt-api"
# The exec base for the tools to use. If this is initialised
# and any of the program variables are not initialised
# then they will be automatically filled in based on this variable.
EXEC_BASE=/work/builds/gcc/current/arm-eabi/install/bin/arm-eabi
# The compiler to use:
GCC=${EXEC_BASE}-gcc # This is an example of how this variable would
# be automatically initialised.
# The other program variables are:
# OBJCOPY
# OBJDUMP
# READELF
}
#----------------------------------------------------------------
show_help ()
{
# The following exec goop is so that we don't have to manually
# redirect every message to stderr in this function.
exec 4>&1 # Save stdout fd to fd #4.
exec 1>&2 # Redirect stdout to stderr.
cat <<__EOM__
This is a shell script that acts as a wrapper to gcc and which allows the
building of "fat binaries". These are files that contain code that supports
two different APIs. The normal API code is visible to other tools and the
kernel, whilst the alternative API code is stored hidden inside the binary.
The --fat-swap option of this script can be used to swap the two APIs over.
Usage: $SCRIPT_NAME {<fat-option(s)>} [<fat-command>|<gcc-options>] <file-name(s)>
<fat-option> is zero or more of:
--fat-version
Report the version of this script, plus the user-customisable variables.
--fat-help
Displays this information.
--fat-verbose
This tells the script to be verbose about what it is doing. The same
effect can achieved by using gcc's --verbose command line option,
except that that makes gcc generate verbose output as well.
--fat-save-temps
Do not delete any temporary files created by the script.
<fat-command> is one of:
--fat-status
Reports on the status of the specified files, showing which API is in
use and which is stored internally.
--fat-swap
Swaps the contents of the specified files so that the stored
alternative version is the one that will be seen by other tools.
<gcc-options>
This is a normal gcc command line. If the -c option is present
then a compilation will be performed, creating a fat object file.
Otherwise a link will be performed, creating a fat executable.
__EOM__
exec 1>&4 # Copy stdout fd back from temporary save fd, #4
}
#----------------------------------------------------------------
# Utility functions:
report ()
{
if [ $SHOW_PROGRESS -ne 0 ]
then
echo $SCRIPT_NAME": " ${1+"$@"}
fi
}
verbose ()
{
if [ $SHOW_PROGRESS -gt 1 ] || [ $SHOW_PROGRESS -lt -1 ]
then
report ${1+"$@"}
fi
}
warn ()
{
if test "x$1" != "x" ;
then
report "Warning: $1"
fi
}
fail ()
{
echo "$SCRIPT_NAME: Internal error: " ${1+"$@"}
exit 1
}
init_internal ()
{
# The version of this script:
VERSION=0.5
# The name that was used to invoke this script.
SCRIPT_NAME=`basename $0`
# FIXME: If the $prog is "gcc" then maybe an alternative name should be used ?
# Multi-state variable:
# -2 => Do not do anything, be verbose about what would be done.
# -1 => Do not do anything, just show what would be done.
# 0 => Do not report anything, just return an exit code.
# 1 => Provide a basic desription of what is going on.
# 2 => Be verbose about what is going on.
SHOW_PROGRESS=1
# Set to 1 if temporary files should not be deleted.
SAVE_TEMPS=0
# Fill in the executable variables, if necessary.
if test "x$GCC" == "x" ;
then
if test "x$EXEC_BASE" == "x" ;
then
fail "No GCC executable specified and no base name either."
else
GCC=${EXEC_BASE}-gcc
fi
fi
if test "x$OBJCOPY" == "x" ;
then
if test "x$EXEC_BASE" == "x" ;
then
fail "No OBJCOPY executable specified and no base name either."
else
OBJCOPY=${EXEC_BASE}-objcopy
fi
fi
if test "x$OBJDUMP" == "x" ;
then
if test "x$EXEC_BASE" == "x" ;
then
fail "No OBJDUMP executable specified and no base name either."
else
OBJDUMP=${EXEC_BASE}-objdump
fi
fi
if test "x$READELF" == "x" ;
then
if test "x$EXEC_BASE" == "x" ;
then
fail "No READELF executable specified and no base name either."
else
READELF=${EXEC_BASE}-readelf
fi
fi
}
# Delete a file or directory.
delete_file ()
{
if [ $SAVE_TEMPS -eq 0 ]
then
verbose "Deleting: $1"
if [ $SHOW_PROGRESS -ge 0 ]
then
rm -fr $1
fi
fi
}
# syntax: run_command <command> [<args>]
# If being verbose report the command being run, and
# the directory in which it is run.
# If not performing a dry run execute the command and
# issue a warning message if the command fails.
# Sets RUN_RESULT to 0 upon success, 1 otherwise.
run_command ()
{
RUN_RESULT=0
verbose "Executing: $*"
if [ $SHOW_PROGRESS -lt 0 ]
then
return
fi
( $* ) && return
verbose "Problems encountered whilst executing: $*"
RUN_RESULT=1
}
# Determine which API is in use in a given file.
# Written as separate function in order to make it easier to port
# this script to other architectures.
uses_hard_api ()
{
verbose "Running: $READELF --arch-specific $1 | grep --quiet Tag_ABI_HardFP_use"
return `$READELF --arch-specific $1 | grep --quiet Tag_ABI_HardFP_use`
}
#----------------------------------------------------------------
show_version ()
{
report "Fat Binary building script"
report "Version: $VERSION"
report "Copyright (c) 2011 Red Hat"
report " "
report "GCC executable: $GCC"
report "Objcopy executable: $OBJCOPY"
report "Objdump executable: $OBJDUMP"
report "Readelf executable: $READELF"
report "Alternative API option(s): $ALT_API"
report "Alternative API section prefix: $ALT_PREFIX"
}
# Returns the status of the given file in FILE_STATUS.
# Values are:
# -1 Does not exist/Not readable
# 0 Does not contain alternate API
# 1 Contains alternate API, using soft-API
# 2 Contains alternate API, using hard-API
get_file_status ()
{
if test "x$1" = "x" ;
then
fail "get_file_status needs a filename argument"
fi
if test "x$2" != "x" ;
then
fail "get_file_status only takes one argument"
fi
if [ -r $1 ]
then
if `$OBJDUMP --section-headers $1 | grep --quiet " $ALT_PREFIX"`
then
if uses_hard_api $1
then
FILE_STATUS=2
else
FILE_STATUS=1
fi
else
FILE_STATUS=0
fi
else
FILE_STATUS=-1
fi
}
# syntax: extract_api FILE SECTION NEW_FILE
# Extracts the named section from file and stores it into the new file.
extract_api ()
{
if test "x$3" = "x" ;
then
fail "extract_api needs three arguments"
fi
if test "x$4" != "x" ;
then
fail "extract_api only takes three arguments"
fi
local input_name=$1
local section_name=$2
local output_name=$3
verbose "Extracting section $section_name from $input_name and storing it in $output_name"
run_command $OBJCOPY \
--only-section $section_name \
--output-target=binary \
--set-section-flags $section_name=alloc,contents,load \
$input_name $output_name
if [ $RUN_RESULT -ne 0 ]
then
fail "could not extract section $section_name from $input_name"
fi
# Paranoia check.
get_file_status $output_name
if [ $FILE_STATUS -gt 0 ]
then
fail "extracted alternative API file '$output_name' already contains another API section!"
fi
verbose "Removing section $section_name from $input_name"
run_command $OBJCOPY --remove-section $section_name $input_name
if [ $RUN_RESULT -ne 0 ]
then
fail "could not remove section $section_name from $input_name"
fi
}
# Switch the API on the specified file.
swap_file ()
{
if test "x$1" = "x" ;
then
fail "swap_file needs a filename argument"
fi
if test "x$2" != "x" ;
then
fail "swap_file only takes one argument"
fi
local file_name=`basename $1`
verbose "Swapping APIs in: $file_name"
get_file_status $1
if [ $FILE_STATUS -le 0 ]
then
if [ $FILE_STATUS -lt 0 ]
then
warn "could not find/read file: $file_name"
elif [ $WARN_NO_SWAP -eq 1 ]
then
verbose "$file_name: does not contain an alternative API binary"
fi
return
fi
local alt_api_file=`mktemp fat-alt-XXXXXXXXXX-$file_name`
local sec_name=$ALT_PREFIX.$file_name
extract_api $1 $sec_name $alt_api_file
# Insert the original file as an alternative API section into the temporary file.
run_command $OBJCOPY --add-section $sec_name=$file_name $alt_api_file
if [ $RUN_RESULT -ne 0 ]
then
fail "Could not insert the alternative API code"
fi
verbose "Replace $file_name with $alt_api_file"
mv $1 $1.tmp
mv $alt_api_file $1
delete_file $1.tmp
# Tidy up.
delete_file $alt_api_file
}
# Switch over the APIs in use in the given files.
swap_files ()
{
if test "x$1" = "x" ;
then
warn "no file names specified for --fat-swap option"
fi
WARN_NO_SWAP=1
while [ $# -gt 0 ]
do
if [ -r $1 ]
then
swap_file $1
else
warn "Unable to read file: $1"
fi
shift
done
}
# Scans a list of files, reporting on their API status.
show_status ()
{
if test "x$1" = "x" ;
then
warn "no file names specified for --fat-status option"
fi
while [ $# -gt 0 ]
do
get_file_status $1
case "$FILE_STATUS" in
-1) warn "Unable to read file: $1"
;;
0) report "$1: does not contain an alternative API binary"
;;
1) report "$1: uses the soft API, contains a hard API alternative"
;;
2) report "$1: uses the hard API, contains a soft API alternative"
;;
*) fail "unexpected result from get_file_status"
;;
esac
shift
done
}
# Given SOURCE_FILE as an argument, set OBJECT_FILE to the same with
# the suffix changed to .o and any directories removed.
translate_source_name ()
{
if test "x$1" = "x" ;
then
fail "translate_source_name needs an argument"
fi
if test "x$2" != "x" ;
then
fail "translate_source_name only takes one argument"
fi
# There is probably a sed expression to do this, but I am no good at sed-fu.
local -i index=-1
local -i length=${#1}
while test "x${1:$index:1}" != "x."
do
if [ $((0 - $index)) -eq $length ]
then
OBJECT_FILE=`basename $1`
return
fi
index+=-1
done
OBJECT_FILE=`basename ${1:0:$(($length + $index))}`
OBJECT_FILE+=".o"
}
# Rename all of the filename in SOURCE_FILES into their object file
# equivalents.
rename_source_files ()
{
local -i index=0
while [ $index -lt ${#SOURCE_FILES[*]} ]
do
local OBJECT_FILE
translate_source_name ${SOURCE_FILES[$index]}
SOURCE_FILES[$index]=$OBJECT_FILE
index+=1
done
}
# Link together object files and libraries to create an executable.
# Then re-link them to create an alternative-API executable and
# insert this into the first executable.
perform_link ()
{
if test "x$OUTPUT_FILE" == "x" ;
then
OUTPUT_FILE="a.out"
fi
if [ ${#SOURCE_FILES[*]} -ne 0 ]
then
rename_source_files
elif [ ${#OBJECT_FILES[*]} -eq 0 ]
then
warn "Nothing to do!"
return
fi
run_command $GCC ${SOURCE_FILES[*]} ${OBJECT_FILES[*]} ${GCC_SWITCHES[*]} -o $OUTPUT_FILE
if [ $RUN_RESULT -ne 0 ]
then
warn "Alternative executable not created because original link failed"
return
fi
# Note - we do not have to find and swap any static libraries, or the object
# files involved in the link. The linker will have done all of the searching
# for us, and placed the alternative API files in ALT_PREFIX sections in the
# executable. All we need to do is to extract *all* of the alternate API
# object files from inside the linked binary and then link them using the
# original command line. (This assumes that there will not be any duplicated
# object file names).
declare -a alt_sections
verbose "Runing: $OBJDUMP --section-headers $OUTPUT_FILE | grep $ALT_PREFIX"
read -a alt_sections <<<`$OBJDUMP --section-headers $OUTPUT_FILE | grep --only-matching "$ALT_PREFIX.[^ ]*"`
verbose "Alt section list: ${alt_sections[*]}"
local -i index=0
while [ $index -lt ${#alt_sections[*]} ]
do
alt_api_file=`mktemp fat-sec-XXXXXXXXXX-${alt_sections[$index]}`
extract_api $OUTPUT_FILE ${alt_sections[$index]} $alt_api_file
alt_sections[$index]=$alt_api_file
index+=1
done
# Rerun the gcc command line with the swapped binaries in place
# and creating a new output file.
new_output_file=`mktemp fat-aout-XXXXXXXXXX-$OUTPUT_FILE`
run_command $GCC ${alt_sections[*]} ${GCC_SWITCHES[*]} $ALT_API -o $new_output_file
if [ $RUN_RESULT -ne 0 ]
then
fail "Alternative link failed"
fi
get_file_status $new_output_file
if [ $FILE_STATUS -gt 0 ]
then
fail "New alt file still contains alternative API sections"
fi
# Insert the new output file into the original output file.
run_command $OBJCOPY --add-section $ALT_PREFIX.`basename $OUTPUT_FILE`=$new_output_file $OUTPUT_FILE
if [ $RUN_RESULT -ne 0 ]
then
fail "Unable to store alternative API code inside original binary"
fi
# Tidy up.
delete_file $new_output_file
index=0
while [ $index -lt ${#alt_sections[*]} ]
do
delete_file ${alt_sections[$index]}
index+=1
done
}
# Compile source file(s) to object file(s).
perform_compiles ()
{
if [ ${#SOURCE_FILES[*]} -eq 0 ]
then
fail "No source files found"
fi
# Catch an unusual combination of command line options
# (that is currently unsupported).
if test "x$OUTPUT_FILE" != "x" && [ $NO_LINK -ne 0 ]
then
warn "Using -o to set the output object file name is not supported"
fi
local -i index=0
while [ $index -lt ${#SOURCE_FILES[*]} ]
do
local OBJECT_FILE
translate_source_name ${SOURCE_FILES[$index]}
run_command $GCC -c ${SOURCE_FILES[$index]} -o $OBJECT_FILE ${GCC_SWITCHES[*]}
if [ $RUN_RESULT -ne 0 ]
then
verbose "Compilation failed."
return
fi
local temp_file
local file_name
file_name=`basename $OBJECT_FILE`
temp_file=`mktemp fat-obj-XXXXXXXXXX-$file_name`
run_command $GCC -c ${SOURCE_FILES[$index]} ${GCC_SWITCHES[*]} $ALT_API "-o $temp_file"
if [ $RUN_RESULT -ne 0 ]
then
fail "Alternative compilation failed"
fi
# FIXME: As an optimization we could check here to see if the
# fat binary is essentially identical to the thin binary. If so
# then there is no need to store the full fat binary inside the thin
# one, and instead we could use a marker.
# Store the fat version inside the thin version
run_command $OBJCOPY --add-section $ALT_PREFIX.$OBJECT_FILE=$temp_file $OBJECT_FILE
if [ $RUN_RESULT -ne 0 ]
then
fail "Unable to store alternative API code inside original binary"
fi
delete_file $temp_file
index+=1
done
}
# Parses a GCC command line. The script has already removed any
# its own switches from the command line.
parse_args ()
{
while [ $# -gt 0 ]
do
case "$1" in
# Look for options controlling verbosity.
# FIXME: we only do a simplistic scan. Ideally we would
# scan the command line twice, once for verbosity switches
# and then afterwards for other types of switches.
--verbose | -v)
if [ $SHOW_PROGRESS -eq -1 ]
then
SHOW_PROGRESS=-2
else
SHOW_PROGRESS=2
fi
;;
--quiet | -q)
if [ $SHOW_PROGRESS -gt 0 ]
then
SHOW_PROGRESS=0
fi
;;
# Look for filenames
-o)
if test "x$OUTPUT_FILE" != "x" ;
then
warn "Multiple output file names detected"
else
shift
OUTPUT_FILE=$1
fi
verbose "Output file name: $OUTPUT_FILE"
;;
# Look for compling only.
-c)
NO_LINK=1
;;
# Keep the remaining switches so that we can pass them to gcc
# FIXME: Handle switches that take arguments where the user has not used an equals sign.
-*)
GCC_SWITCHES[${#GCC_SWITCHES[*]}]=$1
verbose "Add $1 to list of gcc command line switches"
;;
# Record source files names.
# FIXME: Add Java, Fortran, etc.
*.cxx | *.cc | *.cpp | *.CPP | *.c | *.S | *.s | *.asm)
SOURCE_FILES[${#SOURCE_FILES[*]}]=$1
verbose "Add $1 to list of source files"
;;
# Anything else is assumed to be an object filename.
# This fails with switches that take an argument.
*)
OBJECT_FILES[${#OBJECT_FILES[*]}]=$1
verbose "Add $1 to list of object files"
;;
esac
shift
done
}
# Execute the rest of the command line, after the script specific
# switches have been removed.
process_files ()
{
# Create arraya for object files and source files.
declare -a OBJECT_FILES
declare -a SOURCE_FILES
declare -a GCC_SWITCHES
NO_LINK=0
OUTPUT_FILE=""
parse_args ${1+"$@"}
if [ ${#SOURCE_FILES[*]} -ne 0 ]
then
perform_compiles
fi
if [ $NO_LINK -eq 0 ]
then
perform_link
fi
}
#-------------------------------------------------------
main ()
{
# Initialise user modifiable variables.
init_user
# Initialise internal variables.
init_internal
if test "x$1" = "x" ;
then
warn "use the --fat-help option to see a description of this script"
exit 1
fi
while [ $# -gt 0 ]
do
# For simplicity we specify that any script
# specific switch(es) must come first.
case "$1" in
--version | --fat-version) show_version
;;
--fat-help) show_help
;;
--fat-save-temps) SAVE_TEMPS=1
;;
--fat-verbose) SHOW_PROGRESS=2
;;
--fat-status) shift ; show_status ${1+"$@"} ; break
;;
--fat-swap) shift ; swap_files ${1+"$@"} ; break
;;
*) process_files ${1+"$@"} ; break
;;
esac
shift
done
exit 0
}
#-------------------------------------------------------
# Invoke main
main ${1+"$@"}
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