blob: da1ce64a7236a2a1753a957c02d13304fdcbaafe [file] [log] [blame]
#!/usr/bin/env bash
# Copyright 2016 The Fuchsia Authors
#
# Use of this source code is governed by a MIT-style
# license that can be found in the LICENSE file or at
# https://opensource.org/licenses/MIT
# This script reads the dynamic symbol table of a DSO (ELF file) via nm
# and writes out a sequence of lines for each symbol in the DSO's ABI
# that can be used as C macros. The macro invocations it writes look like:
# TYPE(NAME, [ADDRESS,] SIZE)
# The ADDRESS parameter is included only if the script is given the -a switch.
# The SIZE is forced to 0 for functions if the script is given the -z switch.
# The TYPE is one of:
# COMMON_OBJECT STT_COMMON symbol
# UNDEFINED SHN_UNDEF symbol
# UNDEFINED_WEAK_OBJECT SHN_UNDEF, STB_WEAK, STT_OBJECT symbol
# UNDEFINED_WEAK SHN_UNDEF, STB_WEAK, STT_FUNC symbol
# WEAK_DATA_OBJECT STB_WEAK, STT_OBJECT symbol
# WEAK_FUNCTION STB_WEAK, STT_FUNC symbol
# FUNCTION STB_GLOBAL, STT_FUNC symbol
# RODATA_OBJECT STB_GLOBAL, STT_OBJECT symbol in R/O section
# DATA_OBJECT STB_GLOBAL, STT_OBJECT symbol in R/W section
# BSS_OBJECT STB_GLOBAL symbol in SHT_NOBITS section
# (nm actually uses a haphazard combination of ELF symbol details and
# section details to choose its type letters rather than directly using the
# ELF symbol bits consistently. But the type letters map to these symbol
# details when symbols are defined in the usual ways by a compiler.)
if [ "$(basename $0)" = "sh" ]
then
set -e
else
set -o pipefail -e
fi
usage() {
echo >&2 "Usage: $0 NM [-a] [-z] DSO OUTPUT [DEPFILE]"
exit 2
}
if [ $# -lt 3 ]; then
usage
fi
NM="$1"
shift
show_address=false
zero_function_size=false
while [ $# -gt 0 ]; do
case "$1" in
-a) show_address=true ;;
-z) zero_function_size=true ;;
*) break ;;
esac
shift
done
if [ $# -ne 2 -a $# -ne 3 ]; then
usage
fi
DSO="$1"
OUTPUT="$2"
DEPFILE="$3"
USED_FILES=()
if [[ "$DSO" == @* ]]; then
rspfile="${DSO#@}"
DSO="$(< "$rspfile")"
USED_FILES+=("$rspfile" "$DSO")
else
USED_FILES+=("$DSO")
fi
if [ -n "$DEPFILE" ]; then
echo "$OUTPUT: ${USED_FILES[*]}" > "$DEPFILE"
fi
dump_names() {
"$NM" -P -g -D -S "$DSO"
}
massage() {
local read name type addr size
while read name type addr size; do
# The numbers are printed in hex, but without a leading "0x" indicator.
addr="0x$addr"
if [ -z "$size" ]; then
size="0x0"
else
size="0x$size"
fi
case "$name" in
# Linkers sometimes emit these symbols into .dynsym, but they are useless
# and should not be consider part of the ABI.
__bss_start|__bss_start__|__bss_end__|_bss_end__) continue ;;
__data_start|__end__|_stack|_etext|_edata|_end) continue ;;
__start_xray_fn_idx|__stop_xray_fn_idx) continue ;;
__start_xray_instr_map|__stop_xray_instr_map) continue ;;
esac
case "$type" in
C) type=COMMON_OBJECT ;;
U) type=UNDEFINED ;;
v) type=UNDEFINED_WEAK_OBJECT ;;
w) type=UNDEFINED_WEAK ;;
V) type=WEAK_DATA_OBJECT ;;
W) type=WEAK_FUNCTION ;;
T) type=FUNCTION ;;
R) type=RODATA_OBJECT ;;
D) type=DATA_OBJECT ;;
B) type=BSS_OBJECT ;;
*)
echo >&2 "$0: Unhandled type '${type}' for symbol '${name}'"
exit 1
;;
esac
if $show_address; then
address_item=", $addr"
else
address_item=
fi
if $zero_function_size; then
case $type in
FUNCTION|WEAK_FUNCTION) size="0x0" ;;
esac
fi
echo "${type}(${name}${address_item}, ${size})"
done
}
trap 'rm -f "$OUTPUT" ${DEPFILE:+$"DEPFILE"}' ERR HUP INT TERM
dump_names | massage > "$OUTPUT"