#!/usr/bin/env python3
#
# Copyright (c) 2018 Intel Corporation.
#
# SPDX-License-Identifier: Apache-2.0
#

# This script will relocate .text, .rodata, .data and .bss sections from required files
# and places it in the required memory region. This memory region and file
# are given to this python script in the form of a string.
# Example of such a string would be:
# SRAM2:/home/xyz/zephyr/samples/hello_world/src/main.c,\
# SRAM1:/home/xyz/zephyr/samples/hello_world/src/main2.c
# To invoke this script:
# python3 gen_relocate_app.py -i input_string -o generated_linker -c generated_code
# Configuration that needs to be sent to the python script.
# if the memory is like SRAM1/SRAM2/CCD/AON then place full object in
# the sections
# if the memory type is appended with _DATA / _TEXT/ _RODATA/ _BSS only the
# selected memory is placed in the required memory region. Others are
# ignored.
# NOTE: multiple regions can be appended together like SRAM2_DATA_BSS
# this will place data and bss inside SRAM2

import sys
import argparse
import os
import glob
import warnings
from elftools.elf.elffile import ELFFile

# This script will create linker comands for text,rodata data, bss section relocation

PRINT_TEMPLATE = """
                KEEP(*({0}))
"""

SECTION_LOAD_MEMORY_SEQ = """
        __{0}_{1}_rom_start = LOADADDR(_{2}_{3}_SECTION_NAME);
"""

LOAD_ADDRESS_LOCATION_FLASH = "GROUP_DATA_LINK_IN({0}, FLASH)"
LOAD_ADDRESS_LOCATION_BSS = "GROUP_LINK_IN({0})"

# generic section creation format
LINKER_SECTION_SEQ = """

/* Linker section for memory region {2} for  {3} section  */

	SECTION_PROLOGUE(_{2}_{3}_SECTION_NAME, (OPTIONAL),)
        {{
                . = ALIGN(4);
                {4}
                . = ALIGN(4);
	}} {5}
        __{0}_{1}_end = .;
        __{0}_{1}_start = ADDR(_{2}_{3}_SECTION_NAME);
        __{0}_{1}_size = SIZEOF(_{2}_{3}_SECTION_NAME);
"""

SOURCE_CODE_INCLUDES = """
/* Auto generated code. Do not modify.*/
#include <zephyr.h>
#include <linker/linker-defs.h>
#include <kernel_structs.h>
"""

EXTERN_LINKER_VAR_DECLARATION = """
extern char __{0}_{1}_start[];
extern char __{0}_{1}_rom_start[];
extern char __{0}_{1}_size[];
"""


DATA_COPY_FUNCTION = """
void data_copy_xip_relocation(void)
{{
{0}
}}
"""

BSS_ZEROING_FUNCTION = """
void bss_zeroing_relocation(void)
{{
{0}
}}
"""

MEMCPY_TEMPLATE = """
	(void)memcpy(&__{0}_{1}_start, &__{0}_{1}_rom_start,
		     (u32_t) &__{0}_{1}_size);

"""

MEMSET_TEMPLATE = """
 	(void)memset(&__{0}_bss_start, 0,
		     (u32_t) &__{0}_bss_size);
"""

def find_sections(filename, full_list_of_sections):
    with open(filename, 'rb') as obj_file_desc:
        full_lib = ELFFile(obj_file_desc)
        if not full_lib:
            print("Error parsing file: ", filename)
            sys.exit(1)

        sections = [x for x in full_lib.iter_sections()]


        for section in sections:

            if ".text." in  section.name:
                full_list_of_sections["text"].append(section.name)

            if ".rodata." in  section.name:
                full_list_of_sections["rodata"].append(section.name)

            if ".data." in  section.name:
                full_list_of_sections["data"].append(section.name)

            if ".bss." in  section.name:
                full_list_of_sections["bss"].append(section.name)

            # Common variables will be placed in the .bss section
            # only after linking in the final executable. This "if" findes
            # common symbols and warns the user of the problem.
            # The solution to which is simply assigning a 0 to
            # bss variable and it will go to the required place.
            if ".symtab" in  section.name:
                symbols = [x for x in section.iter_symbols()]
                for symbol in symbols:
                    if symbol.entry["st_shndx"] == 'SHN_COMMON':
                        warnings.warn("Common variable found. Move "+
                                      symbol.name + " to bss by assigning it to 0/NULL")

    return full_list_of_sections


def assign_to_correct_mem_region(memory_type,
                                 full_list_of_sections, complete_list_of_sections):
    all_regions = False
    iteration_sections = {"text":False, "rodata":False, "data":False, "bss":False}
    if "_TEXT" in memory_type:
        iteration_sections["text"] = True
        memory_type = memory_type.replace("_TEXT", "")
    if "_RODATA" in memory_type:
        iteration_sections["rodata"] = True
        memory_type = memory_type.replace("_RODATA", "")
    if "_DATA" in memory_type:
        iteration_sections["data"] = True
        memory_type = memory_type.replace("_DATA", "")
    if "_BSS" in memory_type:
        iteration_sections["bss"] = True
        memory_type = memory_type.replace("_BSS", "")
    if not (iteration_sections["data"] or iteration_sections["bss"] or
            iteration_sections["text"] or iteration_sections["rodata"]):
        all_regions = True

    if memory_type in complete_list_of_sections:
        for iter_sec in ["text", "rodata", "data", "bss"]:
            if ((iteration_sections[iter_sec] or all_regions) and
                    full_list_of_sections[iter_sec] != []):
                complete_list_of_sections[memory_type][iter_sec] += (
                    full_list_of_sections[iter_sec])
    else:
        #new memory type was found. in which case just assign the
        # full_list_of_sections to the memorytype dict
        tmp_list = {"text":[], "rodata":[], "data":[], "bss":[]}
        for iter_sec in ["text", "rodata", "data", "bss"]:
            if ((iteration_sections[iter_sec] or all_regions) and
                    full_list_of_sections[iter_sec] != []):
                tmp_list[iter_sec] = full_list_of_sections[iter_sec]

        complete_list_of_sections[memory_type] = tmp_list

    return complete_list_of_sections


def print_linker_sections(list_sections):
    print_string = ''
    for section in list_sections:
        print_string += PRINT_TEMPLATE.format(section)
    return print_string

def string_create_helper(region, memory_type,
                         full_list_of_sections, load_address_in_flash):
    linker_string = ''
    if load_address_in_flash:
        load_address_string = LOAD_ADDRESS_LOCATION_FLASH.format(memory_type)
    else:
        load_address_string = LOAD_ADDRESS_LOCATION_BSS.format(memory_type)
    if full_list_of_sections[region] != []:
        # Create a complete list of funcs/ variables that goes in for this
        # memory type
        tmp = print_linker_sections(full_list_of_sections[region])
        linker_string += LINKER_SECTION_SEQ.format(memory_type.lower(), region,
                                                   memory_type.upper(), region.upper(),
                                                   tmp, load_address_string)

        if load_address_in_flash:
            linker_string += SECTION_LOAD_MEMORY_SEQ.format(memory_type.lower(),
                                                            region,
                                                            memory_type.upper(),
                                                            region.upper())

    return linker_string


def generate_linker_script(linker_file, complete_list_of_sections):
    gen_string = ''
    for memory_type, full_list_of_sections in complete_list_of_sections.items():
        gen_string += string_create_helper("text", memory_type, full_list_of_sections, 1)
        gen_string += string_create_helper("rodata", memory_type, full_list_of_sections, 1)
        gen_string += string_create_helper("data", memory_type, full_list_of_sections, 1)
        gen_string += string_create_helper("bss", memory_type, full_list_of_sections, 0)

    #finally writting to the linker file
    with open(linker_file, "a+") as file_desc:
        file_desc.write(gen_string)

def generate_memcpy_code(memory_type, full_list_of_sections, code_generation):

    all_sections = True
    generate_section = {"text":False, "rodata":False, "data":False, "bss":False}
    for section_name in ["_TEXT", "_RODATA", "_DATA", "_BSS"]:
        if section_name in memory_type:
            generate_section[section_name.lower()[1:]] = True
            memory_type = memory_type.replace(section_name, "")
            all_sections = False

    if all_sections:
        generate_section["text"] = True
        generate_section["rodata"] = True
        generate_section["data"] = True
        generate_section["bss"] = True


    #add all the regions that needs to be copied on boot up
    for mtype in ["text", "rodata", "data"]:
        if full_list_of_sections[mtype] and generate_section[mtype]:
            code_generation["copy_code"] += MEMCPY_TEMPLATE.format(memory_type.lower(), mtype)
            code_generation["extern"] += EXTERN_LINKER_VAR_DECLARATION.format(
                memory_type.lower(), mtype)

    # add for all the bss data that needs to be zeored on boot up
    if full_list_of_sections["bss"] and generate_section["bss"]:
        code_generation["zero_code"] += MEMSET_TEMPLATE.format(memory_type.lower())
        code_generation["extern"] += EXTERN_LINKER_VAR_DECLARATION.format(
            memory_type.lower(), "bss")

    return code_generation

def dump_header_file(header_file, code_generation):
    code_string = ''
    # create a dummy void function if there is no code to generate for
    # bss/data/text regions

    code_string += code_generation["extern"]

    if  code_generation["copy_code"]:
        code_string += DATA_COPY_FUNCTION.format(code_generation["copy_code"])
    else:
        code_string += DATA_COPY_FUNCTION.format("void;")
    if code_generation["zero_code"]:
        code_string += BSS_ZEROING_FUNCTION.format(code_generation["zero_code"])
    else:
        code_string += BSS_ZEROING_FUNCTION.format("return;")


    with open(header_file, "w") as header_file_desc:
        header_file_desc.write(SOURCE_CODE_INCLUDES)
        header_file_desc.write(code_string)

def parse_args():
    global args
    parser = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=argparse.RawDescriptionHelpFormatter)
    parser.add_argument("-d", "--directory", required=True,
                        help="obj file's directory")
    parser.add_argument("-i", "--input_rel_dict", required=True,
                        help="input src:memory type(sram2 or ccm or aon etc) string")
    parser.add_argument("-o", "--output", required=False, help="Output ld file")
    parser.add_argument("-c", "--output_code", required=False,
                        help="Output relocation code header file")
    parser.add_argument("-v", "--verbose", action="count", default=0,
                        help="Verbose Output")
    args = parser.parse_args()

#return the absolute path for the object file.
def get_obj_filename(searchpath, filename):
    # get the object file name which is almost always pended with .obj
    obj_filename = filename.split("/")[-1] + ".obj"

    for dirpath, dirs, files in os.walk(searchpath):
        for filename1 in files:
            if filename1 == obj_filename:
                if filename.split("/")[-2] in dirpath.split("/")[-1]:
                    fullname = os.path.join(dirpath, filename1)
                    return fullname


# Create a dict with key as memory type and files as a list of values.
def create_dict_wrt_mem():
#need to support wild card *
    rel_dict = dict()
    if args.input_rel_dict == '':
        print("Disable CONFIG_CODE_DATA_RELOCATION if no file needs relocation")
        sys.exit(1)
    for line in args.input_rel_dict.split(';'):
        mem_region, file_name = line.split(':')

        file_name_list = glob.glob(file_name)
        if not file_name_list:
            warnings.warn("File: "+file_name+" Not found")
            continue
        if mem_region == '':
            continue
        if args.verbose:
            print("Memory region ", mem_region, " Selected for file:", file_name_list)
        if mem_region in rel_dict:
            rel_dict[mem_region].extend(file_name_list)
        else:
            rel_dict[mem_region] = file_name_list

    return rel_dict


def main():
    parse_args()
    searchpath = args.directory
    linker_file = args.output
    rel_dict = create_dict_wrt_mem()
    complete_list_of_sections = {}

    # Create/or trucate file contents if it already exists
    # raw = open(linker_file, "w")

    code_generation = {"copy_code": '', "zero_code":'', "extern":''}
    #for each memory_type, create text/rodata/data/bss sections for all obj files
    for  memory_type, files in rel_dict.items():
        full_list_of_sections = {"text":[], "rodata":[], "data":[], "bss":[]}

        for filename in files:
            obj_filename = get_obj_filename(searchpath, filename)
            # the obj file wasn't found. Probably not compiled.
            if not obj_filename:
                continue

            full_list_of_sections = find_sections(obj_filename, full_list_of_sections)

        #cleanup and attach the sections to the memory type after cleanup.
        complete_list_of_sections = assign_to_correct_mem_region(memory_type,
                                                                 full_list_of_sections,
                                                                 complete_list_of_sections)

    generate_linker_script(linker_file, complete_list_of_sections)
    for mem_type, list_of_sections in complete_list_of_sections.items():
        code_generation = generate_memcpy_code(mem_type,
                                               list_of_sections, code_generation)

    dump_header_file(args.output_code, code_generation)

if __name__ == '__main__':
    main()