#! /usr/bin/env python

#
# Copyright (c) 2015 Wind River Systems, Inc.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1) Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# 2) Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# 3) Neither the name of Wind River Systems nor the names of its contributors
# may be used to endorse or promote products derived from this software without
# specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#

# Arguments:
#   - name of ELF image

# Output:
#  - sends section and RAM/ROM usage to standard output

import os
import sys
import subprocess

xip_rom_size = 0          # XIP ROM usage in bytes
xip_ram_size = 0          # XIP RAM usage in bytes
ram_size = 0              # non-XIP RAM usage in bytes

objdump_list = []         # data gleaned from "objdump -h"


def is_xip(filename):
    """ Determine if image is configured for XIP """

    # Search for CONFIG_XIP in the ELF's list of symbols using NM and AWK.
    # GREP can not be used as it returns an error if the symbol is not found.
    is_xip_command = "nm " + filename + " | awk '/CONFIG_XIP/ { print $3 }'"

    is_xip_output = subprocess.check_output(is_xip_command, shell=True)

    return (len(is_xip_output) != 0)


def calculate_sizes(filename):
    """ Calculate RAM and ROM usage by section """

    global ram_size
    global xip_rom_size
    global xip_ram_size

    objdump_command = "objdump -h " + filename
    objdump_output = subprocess.check_output(objdump_command,
                                             shell=True).splitlines()

    for line in objdump_output:
        words = line.split()

        if (len(words) == 0):               # Skip lines that are too short
            continue

        index = words[0]
        if (not index[0].isdigit()):        # Skip lines that do not start
            continue                        # with a digit

        name = words[1]                     # Skip lines with section names
        if (name[0] == '.'):                # starting with '.'
            continue

        size = int(words[2], 16)
        phys_addr = int(words[4], 16)

        # Add section to memory use totals (for both non-XIP and XIP scenarios)
        #
        # In an XIP image, the following sections are placed into ROM:
        #     text, ctors, rodata and datas
        # In an XIP image, the following sections are placed into RAM:
        #     datas, bss and noinit
        # In a non-XIP image, the following sections are placed into RAM
        #     text, ctors, rodata, datas, bss and noinit
        #
        # Unrecognized section names are tagged with the '*' character
        # and are not included in the calculations.

        ram_size += size

        if ((name == "text") or (name == "ctors") or (name == "rodata")):
            xip_rom_size += size
        elif (name == "datas"):
            xip_rom_size += size
            xip_ram_size += size
        elif ((name == "bss") or (name == "noinit")):
            xip_ram_size += size
        else:
            name += "*"             # Unrecognized section
            ram_size -= size        # Undo the calculation

        objdump_list.append("%-17s 0x%08x %8d %5x" %
                            (name, phys_addr, size, size))


def display_sizes(filename):
    """ Display the section and memory usage """

    print("SECTION NAME         ADDRESS     SIZE   HEX")

    for line in objdump_list:
        print(line)
    print

    if (is_xip(filename)):
        print("Total: %d bytes (ROM) + %d bytes (RAM)" %
              (xip_rom_size, xip_ram_size))
    else:
        print("Total: %d bytes (RAM)" % ram_size)


def is_elf(filename):
    """ Determine if 'filename' is an ELF image file """

    magic = 0

    with open(filename, "rb") as f:
        magic = f.read(4)

    return (magic == "\x7fELF")


def display_help():
    """ Display tool help information """

    print("Usage: truesize <elf_file>")
    print("Display section information and calculated memory usage.")
    print("Unrecognized sections are tagged with '*' and are not included")
    print("in the calculations.")


def sanitize_arguments():
    """ Perform sanity checks on the command line arguments """

    # Ensures that the correct number of arguments is supplied to the tool and
    # that the specified file is an ELF image.

    if ((len(sys.argv) != 2) or (not is_elf(sys.argv[1]))):
        display_help()
        sys.exit(1)


###############################################################################
#
# TRUESIZE MAINLINE
#


sanitize_arguments()
calculate_sizes(sys.argv[1])
display_sizes(sys.argv[1])