# Copyright lowRISC contributors.
# Licensed under the Apache License, Version 2.0, see LICENSE for details.
# SPDX-License-Identifier: Apache-2.0

project(
  'opentitan', 'c', 'cpp',
  version: '0.1',
  meson_version: '>=0.53.0', # Matches version in python-requirements.txt
  default_options: [
    'c_std=c11',
    'build.c_std=c11',
    'cpp_std=c++14',
    'build.cpp_std=c++14',
    'warning_level=2',
    'werror=true',
    'debug=true',
    'b_staticpic=false', # Disable PIC for device static libraries
    'b_pie=false',       # Disable PIE for device executables
  ],
)

# We allow both GCC and Clang, but these minimum versions.
required_gcc_version = '>=5'
required_clang_version = '>=3.5'

ot_version = get_option('ot_version')
if ot_version == 'undef'
  error('ot_version option not set. Please run meson with a valid OpenTitan version option.')
endif

bin_dir = get_option('bin_dir')
if bin_dir == 'undef'
  error('bin_dir option not set. Please run meson with a valid binary directory option.')
endif

# See the comment in `./util/meson-purge-includes.sh` for why this is necessary.
if not get_option('keep_includes')
  meson.add_postconf_script(meson.source_root() + '/util/meson-purge-includes.sh')
endif

coverage = get_option('coverage')
# Coverage requires clang.
if coverage and meson.get_compiler('c').get_id() != 'clang'
  error('Coverage requires clang.')
endif

# Check C/C++ compiler version numbers.
c_compilers = {
  'C compiler for host': meson.get_compiler('c', native: true),
  'C compiler for device': meson.get_compiler('c', native: false),
  'C++ compiler for host': meson.get_compiler('cpp', native: true),
}
foreach kind, compiler : c_compilers
  if compiler.get_id() == 'clang'
    if not compiler.version().version_compare(required_clang_version)
      error('@0@ version mismatch, @1@ required.'.format(kind, required_clang_version))
    endif
  elif compiler.get_id() == 'gcc'
    if not compiler.version().version_compare(required_gcc_version)
      error('@0@ version mismatch, @1@ required.'.format(kind, required_gcc_version))
    endif
  else
    warning('Unsupported @0@: @1@'.format(kind, compiler.get_id()))
    message('Please ensure this compiler satisfies the OpenTitan requirements in:')
    message(' https://docs.opentitan.org/doc/ug/install_instructions/#system-requirements')
  endif
endforeach


# C compiler arguments to to catch common errors, used on all builds.
extra_warning_args = [
  '-Wimplicit-fallthrough', # Error on implicit fallthrough
  '-Wswitch-default', # Ensure all switches have default statements
  '-Wno-covered-switch-default', # We require `default:` always.
  '-Wgnu', # We aim to be standards compliant, and avoid gnu extensions.
  '-Wno-error=unused-function', # Don't error out on unused functions, only warn.
  # Issues we intend to fix in the future but are currently ignored as there are
  # many places they are triggered.
  '-Wno-unused-parameter',
  '-Wno-sign-compare',
  '-Wno-missing-field-initializers',
  '-Wno-gnu-zero-variadic-macro-arguments',
]

# C compiler arguments to optimize for size, used on cross builds only.
optimize_size_args = [
  '-Os', # General "Optimize for Size" Option
  '-fvisibility=hidden', # Hide symbols by default
]

native_c_compiler = meson.get_compiler('c', native: true)
cross_c_compiler = meson.get_compiler('c', native: false)

if cross_c_compiler.has_argument('-Wa,--no-pad-sections')
  # Don't pad assembly sections. This was originally added to avoid sections
  # being padded to the alignment size. Specifically, .vectors was being
  # padded to 256 bytes when aligning to that value, when it only needed to be
  # 128 bytes long. Clang doesn't do this padding, so restricting this option
  # to GCC doesn't waste space when compiling with Clang.
  optimize_size_args += '-Wa,--no-pad-sections'
endif

# The following flags are applied to *all* builds, both cross builds and native
# builds.
c_cpp_args = [
  # We use absolute include paths as much as possible.
  '-I' + meson.source_root(),
  '-I' + meson.build_root(),
]
add_project_arguments(c_cpp_args, language: ['c', 'cpp'], native: false)
add_project_arguments(c_cpp_args, language: ['c', 'cpp'], native: true)

# The following flags are applied only to cross builds
c_cpp_cross_args = [
  # Do not use standard system headers
  '-nostdinc',
  # Use OpenTitan's freestanding headers instead
  '-isystem' + meson.source_root() / 'sw/device/lib/base/freestanding',
  # Don't emit unwinding information
  '-fno-asynchronous-unwind-tables',
  # Don't use COMMON sections for uninitialized globals
  '-fno-common',
  # Place each function into its own section (used in conjunction with
  # --gc-sections to remove unused functions from output files).
  '-ffunction-sections',
]

# Add extra warning flags for cross builds, if they are supported.
foreach warning_arg : extra_warning_args
  if cross_c_compiler.has_argument(warning_arg)
    c_cpp_cross_args += [warning_arg]
  endif
endforeach

# Add the flags for cross builds.
add_project_arguments(
  c_cpp_cross_args,
  optimize_size_args,
  language: ['c', 'cpp'], native: false)
# Add a C-only flag for cross builds.
add_project_arguments(
  '-Wstrict-prototypes', # Ban K&R Declarations/Definitions.
  language: ['c'], native: false)

# The following flags are applied only to cross builds
c_cpp_cross_link_args = [
  # Do not use standard system startup files or libraries
  '-nostartfiles',
  '-nostdlib',
   # Only link static files
  '-static',
  # Warn if we use COMMON
  '-Wl,--warn-common',
  # Warn if we include orphan sections
  '-Wl,--orphan-handling=warn',
  # Turn Linker Warnings into Errors
  '-Wl,--fatal-warnings',
  # Garbage collect unused sections.
  '-Wl,--gc-sections',
]
add_project_link_arguments(
  c_cpp_cross_link_args,
  language: ['c', 'cpp'], native: false)

# The following flags are applied only to native builds
c_cpp_native_args = [
  # Use a define to exclude libc redefinitions.
  '-DHOST_BUILD',
]

# Add Extra warning flags for native builds, if they are supported.
foreach warning_arg : extra_warning_args
  if native_c_compiler.has_argument(warning_arg)
    c_cpp_native_args += [warning_arg]
  endif
endforeach

# Add the flags for native builds.
add_project_arguments(
  c_cpp_native_args,
  language: ['c', 'cpp'], native: true)
# Add a C-only flag for native builds.
add_project_arguments(
  '-Wstrict-prototypes', # Ban K&R Declarations/Definitions.
  language: ['c'], native: true)

# Common program references.
prog_python = import('python').find_installation('python3')
prog_env = find_program('env')
prog_srec_cat = find_program('srec_cat')

prog_ld = find_program('ld')
prog_as = find_program('as')
prog_objdump = find_program('objdump')
prog_objcopy = find_program('objcopy')

prog_otbn_as = meson.source_root() / 'hw/ip/otbn/util/otbn-as'
prog_otbn_ld = meson.source_root() / 'hw/ip/otbn/util/otbn-ld'

# Hardware register headers. These are generated from HJSON files, and accesible
# in C via |#include "{IP_NAME}_regs.h"|.
gen_hw_hdr = generator(
  prog_python,
  output: '@BASENAME@_regs.h',
  arguments: [
    '@SOURCE_DIR@/util/regtool.py', '-D', '-o', '@OUTPUT@',
    '@INPUT@',
  ],
)

# TODO: Considering moving these into hw/ip directories.
TOPNAME='top_earlgrey'
hw_ip_aes_reg_h = gen_hw_hdr.process('hw/ip/aes/data/aes.hjson')
hw_ip_alert_handler_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/alert_handler/data/autogen/alert_handler.hjson')
hw_ip_aon_timer_reg_h = gen_hw_hdr.process('hw/ip/aon_timer/data/aon_timer.hjson')
hw_ip_clkmgr_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/clkmgr/data/autogen/clkmgr.hjson')
hw_ip_entropy_src_reg_h = gen_hw_hdr.process('hw/ip/entropy_src/data/entropy_src.hjson')
hw_ip_flash_ctrl_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/flash_ctrl/data/autogen/flash_ctrl.hjson')
hw_ip_gpio_reg_h = gen_hw_hdr.process('hw/ip/gpio/data/gpio.hjson')
hw_ip_hmac_reg_h = gen_hw_hdr.process('hw/ip/hmac/data/hmac.hjson')
hw_ip_kmac_reg_h = gen_hw_hdr.process('hw/ip/kmac/data/kmac.hjson')
hw_ip_i2c_reg_h = gen_hw_hdr.process('hw/ip/i2c/data/i2c.hjson')
hw_ip_keymgr_reg_h = gen_hw_hdr.process('hw/ip/keymgr/data/keymgr.hjson')
hw_ip_lc_ctrl_reg_h = gen_hw_hdr.process('hw/ip/lc_ctrl/data/lc_ctrl.hjson')
hw_ip_otbn_reg_h = gen_hw_hdr.process('hw/ip/otbn/data/otbn.hjson')
hw_ip_otp_ctrl_reg_h = gen_hw_hdr.process('hw/ip/otp_ctrl/data/otp_ctrl.hjson')
hw_ip_spi_device_reg_h = gen_hw_hdr.process('hw/ip/spi_device/data/spi_device.hjson')
hw_ip_sram_ctrl_reg_h = gen_hw_hdr.process('hw/ip/sram_ctrl/data/sram_ctrl.hjson')
hw_ip_entropy_src_reg_h = gen_hw_hdr.process('hw/ip/entropy_src/data/entropy_src.hjson')
hw_ip_csrng_reg_h = gen_hw_hdr.process('hw/ip/csrng/data/csrng.hjson')
hw_ip_edn_reg_h = gen_hw_hdr.process('hw/ip/edn/data/edn.hjson')
hw_ip_rv_timer_reg_h = gen_hw_hdr.process('hw/ip/rv_timer/data/rv_timer.hjson')
hw_ip_uart_reg_h = gen_hw_hdr.process('hw/ip/uart/data/uart.hjson')
hw_ip_usbdev_reg_h = gen_hw_hdr.process('hw/ip/usbdev/data/usbdev.hjson')
hw_ip_pwrmgr_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/pwrmgr/data/autogen/pwrmgr.hjson')
hw_ip_rstmgr_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/rstmgr/data/autogen/rstmgr.hjson')
hw_ip_ibex_reg_h = gen_hw_hdr.process('hw//ip/rv_core_ibex/data/rv_core_ibex.hjson')
hw_top_earlgrey_pinmux_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/pinmux/data/autogen/pinmux.hjson')
hw_top_earlgrey_rv_plic_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/rv_plic/data/autogen/rv_plic.hjson')

# Top Earlgrey library (top_earlgrey)
# The sources for this are generated into the hw hierarchy.
top_earlgrey = declare_dependency(
  link_with: static_library(
    'top_earlgrey_ot',
    sources: [
      'hw/' + TOPNAME + '/sw/autogen/top_earlgrey.c',
    ],
  )
)

subdir('sw')

# Write environment file
prog_meson_write_env = meson.source_root() / 'util/meson_write_env.py'
r = run_command(
  prog_python,
  prog_meson_write_env,

  '--out-file',
  meson.current_build_dir() / '.env',

  'PYTHON=@0@'.format(prog_python.path()),
  'OTBN_AS=@0@'.format(prog_otbn_as),
  'OTBN_LD=@0@'.format(prog_otbn_ld),
  'RV32_TOOL_OBJCOPY=@0@'.format(prog_objcopy.path()),
  'RV32_TOOL_AS=@0@'.format(prog_as.path()),
  'RV32_TOOL_LD=@0@'.format(prog_ld.path()),
  'RV32_TOOL_OBJDUMP=@0@'.format(prog_objdump.path()),
  'RV32_TOOL_OBJCOPY=@0@'.format(prog_objcopy.path()),
)
assert(r.returncode() == 0, 'Error while calling meson_write_env.py.\n' +
  'STDOUT:\n' + r.stdout().strip() + '\n' +
  'STDERR:\n ' + r.stderr().strip())
message(r.stdout().strip())