# Copyright 2022 The Cobalt Authors. All Rights Reserved.
#
# 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
#
#     http://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/toolchain/gcc_toolchain.gni")

# The environment variables that override arguments of
# overridable_gcc_toolchain and overridable_clang_toolchain
# templates in this file.
declare_args() {
  # The full path to the compiler for AR.
  ar_compiler_override = getenv("GN_AR_COMPILER")

  # The full path to the compiler for CC.
  cc_compiler_override = getenv("GN_CC_COMPILER")

  # The full path to the compiler for CXX.
  cxx_compiler_override = getenv("GN_CXX_COMPILER")

  # The full path to the compiler for LD.
  ld_compiler_override = getenv("GN_LD_COMPILER")

  # Optional parameters that control the tools:

  # Extra flags to be appended when compiling C files (but not C++ files).
  c_flags_override = getenv("GN_C_FLAGS")

  # Extra flags to be appended when compiling both C and C++ files. "CPP"
  # stands for "C PreProcessor" in this context, although it can be
  # used for non-preprocessor flags as well. Not to be confused with
  # "CXX" (which follows).
  cpp_flags_override = getenv("GN_CPP_FLAGS")

  # Extra flags to be appended when compiling C++ files (but not C files).
  cxx_flags_override = getenv("GN_CXX_FLAGS")

  # Extra flags to be appended when compiling assembly.
  asm_flags_override = getenv("GN_ASM_FLAGS")

  # Extra flags to be appended when linking.
  ld_flags_override = getenv("GN_LD_FLAGS")
}

# This template applies environment variables overrides to gcc_toolchain in
# build/toolchain/gcc_toolchain.gni.
# The environment variables/gn arguments overrides specified in this file
# will take precedence over the corresponding arguments passed in from the
# invoked gcc_toolchain.
template("overridable_gcc_toolchain") {
  gcc_toolchain(target_name) {
    forward_variables_from(invoker, "*")

    if (ar_compiler_override != "") {
      ar = ar_compiler_override
    }

    if (cc_compiler_override != "") {
      cc = cc_compiler_override
    }

    if (cxx_compiler_override != "") {
      cxx = cxx_compiler_override
    }

    if (ld_compiler_override != "") {
      ld = ld_compiler_override
    }

    if (c_flags_override != "") {
      extra_cflags = c_flags_override
    }

    if (cpp_flags_override != "") {
      extra_cppflags = cpp_flags_override
    }

    if (cxx_flags_override != "") {
      extra_cxxflags = cxx_flags_override
    }

    if (asm_flags_override != "") {
      extra_asmflags = asm_flags_override
    }

    if (ld_flags_override != "") {
      extra_ldflags = ld_flags_override
    }
  }
}

# This template applies environment variables overrides to clang_toolchain
# in build/toolchain/gcc_toolchain.gni.
# This is a shorthand for gcc_toolchain_set_env_vars instances based on the
# Chromium-built version of Clang. Only the toolchain_cpu and toolchain_os
# variables need to be specified by the invoker, and optionally toolprefix if
# it's a cross-compile case. Note that for a cross-compile case this toolchain
# requires a config to pass the appropriate -target option, or else it will
# actually just be doing a native compile. The invoker can optionally override
# use_gold too.
template("overridable_clang_toolchain") {
  if (defined(invoker.toolprefix)) {
    toolprefix = invoker.toolprefix
  } else {
    toolprefix = ""
  }
  if (is_starboard) {
    clang_base_path = invoker.clang_base_path
  }

  overridable_gcc_toolchain(target_name) {
    prefix = rebase_path("$clang_base_path/bin", root_build_dir)
    cc = "$prefix/clang"
    cxx = "$prefix/clang++"
    ld = cxx
    readelf = "${toolprefix}readelf"
    ar = "${prefix}/llvm-ar"
    nm = "nm"

    forward_variables_from(invoker,
                           [
                             "strip",
                             "default_shlib_subdir",
                             "enable_linker_map",
                             "use_unstripped_as_runtime_outputs",
                           ])

    toolchain_args = {
      if (defined(invoker.toolchain_args)) {
        forward_variables_from(invoker.toolchain_args, "*")
      }
      is_clang = true
    }
  }
}