# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
# vim: set filetype=python:
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

@depends(target.os, '--help')
def arm_option_defaults(os, _):
    if os == 'Android':
        arch = 'armv7-a'
        thumb = 'yes'
        fpu = 'neon'
        float_abi = 'softfp'
    else:
        arch = thumb = fpu = float_abi = 'toolchain-default'
    return namespace(
        arch=arch,
        thumb=thumb,
        fpu=fpu,
        float_abi=float_abi,
    )


# Note: '{...|}' in the help of all options with a non-constant default to
# make the lint happy. The first arm is always going to be used, because a
# default is always returned. The lint is fooled by this file being
# conditional. If it weren't conditional, the lint wouldn't ask for '{|}' to
# be there.
js_option('--with-arch', nargs=1,
          default=arm_option_defaults.arch,
          help='{Use specific CPU features (-march=type). Resets thumb, fpu, '
               'float-abi, etc. defaults when set|}')


@depends('--with-arch')
def arch_option(value):
    if value:
        if value[0] != 'toolchain-default':
            return ['-march={}'.format(value[0])]
    return []


js_option('--with-thumb', choices=('yes', 'no', 'toolchain-default'),
          default=arm_option_defaults.thumb,
          nargs='?', help='{Use Thumb instruction set (-mthumb)|}')


def normalize_arm_option(value):
    if value:
        if len(value):
            if value[0] == 'yes':
                return True
            elif value[0] == 'no':
                return False
            else:
                return value[0]
        return True
    return False

@depends('--with-thumb')
def thumb_option(value):
    value = normalize_arm_option(value)
    if value is True:
        return ['-mthumb']
    if value is False:
        return ['-marm']
    return []


js_option('--with-thumb-interwork', choices=('yes', 'no', 'toolchain-default'),
          default='toolchain-default',
          nargs='?', help='Use Thumb/ARM instuctions interwork (-mthumb-interwork)')


@depends('--with-thumb-interwork')
def thumb_interwork_option(value):
    value = normalize_arm_option(value)
    if value is True:
        return ['-mthumb-interwork']
    if value is False:
        return ['-mno-thumb-interwork']
    return []


js_option('--with-fpu', nargs=1,
          default=arm_option_defaults.fpu,
          help='{Use specific FPU type (-mfpu=type)|}')


@depends('--with-fpu')
def fpu_option(value):
    if value:
        if value[0] != 'toolchain-default':
            return ['-mfpu={}'.format(value[0])]
    return []


js_option('--with-float-abi', nargs=1,
          default=arm_option_defaults.float_abi,
          help='{Use specific arm float ABI (-mfloat-abi=type)|}')


@depends('--with-float-abi')
def float_abi_option(value):
    if value:
        if value[0] != 'toolchain-default':
            return ['-mfloat-abi={}'.format(value[0])]
    return []


js_option('--with-soft-float', choices=('yes', 'no', 'toolchain-default'),
          default='toolchain-default',
          nargs='?', help='Use soft float library (-msoft-float)')


@depends('--with-soft-float')
def soft_float_option(value):
    value = normalize_arm_option(value)
    if value is True:
        return ['-msoft-float']
    if value is False:
        return ['-mno-soft-float']
    return []


check_and_add_gcc_flag('-mno-unaligned-access',
                       when=depends(target.os)(lambda os: os == 'Android'))


@depends(arch_option, thumb_option, thumb_interwork_option, fpu_option,
         float_abi_option, soft_float_option)
def all_flags(arch, thumb, interwork, fpu, float_abi, soft_float):
    return arch + thumb + interwork + fpu + float_abi + soft_float


add_old_configure_assignment('_ARM_FLAGS', all_flags)
add_old_configure_assignment('_THUMB_FLAGS', thumb_option)


@depends(c_compiler, all_flags)
@checking('ARM version support in compiler', lambda x: x.arm_arch)
@imports(_from='textwrap', _import='dedent')
def arm_target(compiler, all_flags):
    # We're going to preprocess the following source to figure out some details
    # about the arm target options we have enabled.
    source = dedent('''\
        %ARM_ARCH __ARM_ARCH
        #if __thumb2__
        %THUMB2 yes
        #else
        %THUMB2 no
        #endif
        // Confusingly, the __SOFTFP__ preprocessor variable indicates the
        // "softfloat" ABI, not the "softfp" ABI.
        #if __SOFTFP__
        %FLOAT_ABI soft
        #elif __ARM_PCS_VFP
        %FLOAT_ABI hard
        #else
        %FLOAT_ABI softfp
        #endif
        // There is more subtlety to it than this preprocessor test, but MOZ_FPU doesn't
        // need to be too fine-grained.
        #if __ARM_NEON
        %FPU neon
        #elif __ARM_VFPV2__ || __ARM_FP == 12
        %FPU vfpv2
        #elif __ARM_VFPV3__
        %FPU vfpv3
        #elif __ARM_VFPV4__ || __ARM_FP == 14
        %FPU vfpv4
        #elif __ARM_FPV5__
        %FPU fp-armv8
        #endif
    ''')
    result = try_invoke_compiler(
        compiler.wrapper + [compiler.compiler] + compiler.flags,
        compiler.language,
        source,
        ['-E'] + all_flags,
    )
    # Metadata emitted by preprocessors such as GCC with LANG=ja_JP.utf-8 may
    # have non-ASCII characters. Treat the output as bytearray.
    data = {'fpu': None}  # fpu may not get a value from the preprocessor.
    for line in result.splitlines():
        if line.startswith(b'%'):
            k, _, v = line.partition(' ')
            k = k.lstrip('%').lower()
            if k == 'arm_arch':
                data[k] = int(v)
            else:
                data[k] = {
                    'yes': True,
                    'no': False,
                }.get(v, v)
            log.debug('%s = %s', k, data[k])

    return namespace(**data)


@depends(arm_target.arm_arch, when=depends(target.os)(lambda os: os == 'Android'))
def armv7(arch):
    if arch < 7:
        die('Android/armv6 and earlier are not supported')


set_config('MOZ_THUMB2', True, when=arm_target.thumb2)
set_define('MOZ_THUMB2', True, when=arm_target.thumb2)
add_old_configure_assignment('MOZ_THUMB2', True, when=arm_target.thumb2)


have_arm_simd = c_compiler.try_compile(body='asm("uqadd8 r1, r1, r2");',
                                       check_msg='for ARM SIMD support in compiler')

set_config('HAVE_ARM_SIMD', have_arm_simd)
set_define('HAVE_ARM_SIMD', have_arm_simd)

have_arm_neon = c_compiler.try_compile(body='asm(".fpu neon\\n vadd.i8 d0, d0, d0");',
                                       check_msg='for ARM NEON support in compiler')

set_config('HAVE_ARM_NEON', have_arm_neon)
set_define('HAVE_ARM_NEON', have_arm_neon)


# We don't need to build NEON support if we're targetting a non-NEON device.
# This matches media/webrtc/trunk/webrtc/build/common.gypi.
@depends(arm_target.arm_arch, when=have_arm_neon)
def build_arm_neon(arm_arch):
    return arm_arch >= 7


set_config('BUILD_ARM_NEON', build_arm_neon)
set_define('BUILD_ARM_NEON', build_arm_neon)


set_config('ARM_ARCH', depends(arm_target.arm_arch)(lambda x: str(x)))
add_old_configure_assignment('ARM_ARCH', depends(arm_target.arm_arch)(lambda x: str(x)))
set_config('MOZ_FPU', arm_target.fpu)


@depends(arm_target.float_abi)
def neon_flags(float_abi):
    # Building with -mfpu=neon requires either the "softfp" or the
    # "hardfp" ABI. Depending on the compiler's default target, and the
    # CFLAGS, the default ABI might be neither, in which case it is the
    # "softfloat" ABI.
    # The "softfloat" ABI is binary-compatible with the "softfp" ABI, so
    # we can safely mix code built with both ABIs. So, if we detect
    # that compiling uses the "softfloat" ABI, force the use of the
    # "softfp" ABI instead.
    flags = ['-mfpu=neon']
    if float_abi == 'soft':
        flags.append('-mfloat-abi=softfp')
    return tuple(flags)


set_config('NEON_FLAGS', neon_flags)