# Copyright 2021 The Pigweed Authors
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may not
# use this file except in compliance with the License. You may obtain a copy of
# the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations under
# the License.

import("//build_overrides/pigweed.gni")

import("$dir_pw_build/target_types.gni")
import("clang_config.gni")

declare_args() {
  pw_toolchain_USE_LLVM_PREBUILT_LIBRARIES = false
}

cortex_m_common_flags = [
  "-mabi=aapcs",
  "-mthumb",
]

cortex_m_software_fpu_flags = [ "-mfloat-abi=soft" ]

cortex_m_hardware_fpu_flags_common = [
  "-mfloat-abi=hard",

  # Used by some pigweed tests/targets to correctly handle hardware FPU
  # behavior.
  "-DPW_ARMV7M_ENABLE_FPU=1",
]

cortex_m_hardware_fpu_flags =
    cortex_m_hardware_fpu_flags_common + [ "-mfpu=fpv4-sp-d16" ]

cortex_m_hardware_fpu_v5_sp_flags =
    cortex_m_hardware_fpu_flags_common + [ "-mfpu=fpv5-sp-d16" ]

# Default config added to all the ARM cortex M targets to link `nosys` library.
config("nosys") {
  libs = [ "nosys" ]
}

config("enable_float_printf") {
  ldflags = [ "-Wl,-u_printf_float" ]
}

# TODO: https://pwbug.dev/434778918 - Workaround for missing builtins in code
# only covered by Bazel, do not use in GN.
pw_source_set("do_not_use_bazel_only") {
  public = [ "extra_builtins.h" ]
}

if (pw_toolchain_USE_LLVM_PREBUILT_LIBRARIES) {
  cortex_m_common_link_flags = [
    "-nostartfiles",
    "-nostdlib++",
    "-unwindlib=none",
  ]
  cortex_m_common_defines = [
    # This macro is used by libc++ headers and normally would expand to std::_libcpp_verbose_abort,
    # but we don't define that since we don't build with libc++ at the moment. For now, we can
    # have this lower to a trap instruction.
    "_LIBCPP_VERBOSE_ABORT(...)=__builtin_trap()",
  ]
  config("cortex_m0plus") {
    cflags = [
      "-mcpu=cortex-m0plus",
      "--target=armv6m-none-eabi",
    ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
    ldflags += cortex_m_common_link_flags
    defines = cortex_m_common_defines
  }

  config("cortex_m4") {
    cflags = [
      "-mcpu=cortex-m4",
      "--target=armv7m-none-eabi",
    ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
    ldflags += cortex_m_common_link_flags
    defines = cortex_m_common_defines
  }

  config("cortex_m55") {
    cflags = [
      "-mcpu=cortex-m55",
      "--target=armv8.1m.main-none-eabi",
    ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
    ldflags += cortex_m_common_link_flags
    defines = cortex_m_common_defines
  }

  config("cortex_m55f") {
    cflags = [
      "-mcpu=cortex-m55",
      "--target=armv8.1m.main-none-eabi",
    ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_hardware_fpu_v5_sp_flags
    asmflags = cflags
    ldflags = cflags
    ldflags += cortex_m_common_link_flags
    defines = cortex_m_common_defines
  }

  config("cortex_m4f") {
    cflags = [
      "-mcpu=cortex-m4",
      "--target=armv7m-none-eabi",
    ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_hardware_fpu_flags
    asmflags = cflags
    ldflags = cflags
    ldflags += cortex_m_common_link_flags
    defines = cortex_m_common_defines
  }
} else {
  cortex_m_hardware_fpu_v5_flags =
      cortex_m_hardware_fpu_flags_common + [ "-mfpu=fpv5-d16" ]

  pw_clang_arm_config("cortex_m0plus") {
    cflags = [ "-mcpu=cortex-m0plus" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
  }

  pw_clang_arm_config("cortex_m4") {
    cflags = [ "-mcpu=cortex-m4" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
  }

  pw_clang_arm_config("cortex_m55") {
    cflags = [ "-mcpu=cortex-m55" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
  }

  pw_clang_arm_config("cortex_m55f") {
    cflags = [ "-mcpu=cortex-m55" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_hardware_fpu_v5_sp_flags
    asmflags = cflags
    ldflags = cflags
  }

  pw_clang_arm_config("cortex_m4f") {
    cflags = [ "-mcpu=cortex-m4" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_hardware_fpu_flags
    asmflags = cflags
    ldflags = cflags
  }

  pw_clang_arm_config("cortex_m3") {
    cflags = [ "-mcpu=cortex-m3" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
    rustflags = [ "--target=thumbv7m-none-eabi" ]
  }

  pw_clang_arm_config("cortex_m7") {
    cflags = [ "-mcpu=cortex-m7" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
  }

  pw_clang_arm_config("cortex_m7f") {
    cflags = [ "-mcpu=cortex-m7" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_hardware_fpu_v5_flags
    asmflags = cflags
    ldflags = cflags
  }

  pw_clang_arm_config("cortex_m33") {
    cflags = [ "-mcpu=cortex-m33" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_software_fpu_flags
    asmflags = cflags
    ldflags = cflags
  }

  pw_clang_arm_config("cortex_m33f") {
    cflags = [ "-mcpu=cortex-m33" ]
    cflags += cortex_m_common_flags
    cflags += cortex_m_hardware_fpu_v5_sp_flags
    asmflags = cflags
    ldflags = cflags
  }
}