# Copyright 2016 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import("//build/config/clang/clang.gni")
import("//build/toolchain/ccache.gni")
import("//build/toolchain/goma.gni")

# Each toolchain must define "stamp" and "copy" tools,
# but they are always the same in every toolchain.
stamp_command = "touch {{output}}"
stamp_description = "STAMP {{output}}"

# We use link instead of copy; the way "copy" tool is being used is
# compatible with links since Ninja is tracking changes to the source.
copy_command = "ln -f {{source}} {{output}} 2>/dev/null || (rm -rf {{output}} && cp -af {{source}} {{output}})"
copy_description = "COPY {{source}} {{output}}"

# Defines a Clang-based toolchain.
#
# Parameters
#
#   toolchain_cpu
#     Required: Value of "current_cpu" inside this toolchain.
#
#   toolchain_os
#     Required: Value of "current_os" inside this toolchain.
#
#   toolchain_args
#     Optional: Scope specifying build arguments to override in this
#     toolchain context.
#     NOTE! Do not use this in the toolchain used as the default toolchain.
#     It will have no effect, and you will be confused.
#
#   use_strip
#     Required: Whether to strip binaries, leaving unstripped ones
#     in lib.unstripped and exe.unstripped subdirectories.
#
#   prefix
#     Optional: The path from which "cc", "cxx", "ar", "ld" and
#     "strip" will be found (unless overridden).  If not given,
#     prefix defaults to $clang_prefix.
#
#   cc
#   cxx
#   ar
#   ld
#   strip
#     Optional: Override default tool names.
#
#   use_ccache, use_goma
#     Optional: Override the global setting, useful to opt out of
#     ccache/goma in a particular toolchain.
#
#   deps
#     Optional: Dependencies of this toolchain.
#
#   propagates_configs
#     Optional: public_configs should escape this toolchain via deps
#
template("clang_toolchain") {
  toolchain(target_name) {
    assert(defined(invoker.toolchain_cpu),
           "clang_toolchain() must specify a \"toolchain_cpu\"")
    assert(defined(invoker.toolchain_os),
           "clang_toolchain() must specify a \"toolchain_os\"")

    compiler_prefix = ""
    if (defined(invoker.use_goma)) {
      use_goma = invoker.use_goma
    }
    if (use_goma) {
      goma_dir = rebase_path(goma_dir)
      compiler_prefix = "$goma_dir/gomacc "
    } else {
      if (defined(invoker.use_ccache)) {
        use_ccache = invoker.use_ccache
      }
      if (use_ccache) {
        compiler_prefix = "ccache "
      }
    }

    prefix = clang_prefix
    if (defined(invoker.prefix)) {
      prefix = invoker.prefix
    }

    # Set all tools to defaults
    cc = "${prefix}/clang"
    cxx = "${prefix}/clang++"
    ar = "${prefix}/llvm-ar"
    ld = cxx

    forward_variables_from(invoker, [ "use_strip" ])
    if (use_strip) {
      if (invoker.toolchain_os == "mac") {
        strip = "xcrun strip"
      } else {
        strip = "${prefix}/llvm-objcopy"
        buildidtool = rebase_path("//sysroot/bin/buildidtool", root_build_dir)
      }
    }

    # Override any tools as requested by the invoker
    if (defined(invoker.cc)) {
      cc = invoker.cc
    }
    if (defined(invoker.cxx)) {
      cxx = invoker.cxx
    }
    forward_variables_from(invoker,
                           [
                             "ar",
                             "deps",
                             "ld",
                             "propagates_configs",
                             "strip",
                           ])

    # These library switches can apply to all tools below
    lib_switch = "-l"
    lib_dir_switch = "-L"

    tool("cc") {
      depfile = "{{output}}.d"
      command = "$cc -MD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
      command_launcher = compiler_prefix
      depsformat = "gcc"
      description = "CC {{output}}"
      outputs = [
        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
      ]
    }

    tool("cxx") {
      depfile = "{{output}}.d"
      command = "$cxx -MD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}} -c {{source}} -o {{output}}"
      command_launcher = compiler_prefix
      depsformat = "gcc"
      description = "CXX {{output}}"
      outputs = [
        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
      ]
    }

    tool("asm") {
      depfile = "{{output}}.d"
      command = "$cc -MD -MF $depfile {{defines}} {{include_dirs}} {{asmflags}} -c {{source}} -o {{output}}"
      command_launcher = compiler_prefix
      depsformat = "gcc"
      description = "ASM {{output}}"
      outputs = [
        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
      ]
    }

    tool("alink") {
      rspfile = "{{output}}.rsp"
      command =
          "rm -f {{output}} && $ar {{arflags}} rcsD {{output}} @\"$rspfile\""
      description = "AR {{output}}"
      rspfile_content = "{{inputs}}"
      outputs = [
        "{{output_dir}}/{{target_output_name}}{{output_extension}}",
      ]
      default_output_dir = "{{target_out_dir}}"
      default_output_extension = ".a"
      output_prefix = "lib"
    }

    tool("solink") {
      outname = "{{target_output_name}}{{output_extension}}"
      outfile = "{{output_dir}}/$outname"
      rspfile = "$outfile.rsp"
      pool = "//build/toolchain:link($default_toolchain)"
      unstripped_outfile = outfile
      if (use_strip) {
        unstripped_outfile = "{{output_dir}}/lib.unstripped/{{target_output_name}}{{output_extension}}"
      }
      if (invoker.toolchain_os == "mac") {
        command = "$ld -shared {{ldflags}} -Wl,-install_name,@rpath/\"{{target_output_name}}{{output_extension}}\" -o \"$unstripped_outfile\" -Wl,-filelist,\"$rspfile\" {{libs}} {{solibs}}"
        rspfile_content = "{{inputs_newline}}"
        default_output_extension = ".dylib"
      } else {
        command = "$ld -shared {{ldflags}} -o \"$unstripped_outfile\" -Wl,--Map=\"$unstripped_outfile.map\" -Wl,-soname=\"$outname\" @\"$rspfile\""
        rspfile_content = "-Wl,--whole-archive {{inputs}} {{solibs}} -Wl,--no-whole-archive {{libs}}"
        default_output_extension = ".so"
      }
      description = "SOLINK $outfile"
      default_output_dir = "{{root_out_dir}}"
      output_prefix = "lib"
      outputs = [
        outfile,
      ]
      if (outfile != unstripped_outfile) {
        outputs += [ unstripped_outfile ]
      }
      if (use_strip) {
        if (invoker.toolchain_os == "mac") {
          command += " && $strip -x \"$unstripped_outfile\" -o \"$outfile\""
        } else {
          command +=
              " && $strip --strip-all \"$unstripped_outfile\" \"$outfile\""
          command +=
              " && $buildidtool -build-id-dir .build-id" +
              " -stamp \"$outfile.build-id.stamp\"" + " -entry \"=$outfile\"" +
              " -entry \".debug=$unstripped_outfile\""
        }
      }
    }

    tool("link") {
      outfile = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
      rspfile = "$outfile.rsp"
      pool = "//build/toolchain:link($default_toolchain)"
      unstripped_outfile = outfile
      if (use_strip) {
        unstripped_outfile = "{{root_out_dir}}/exe.unstripped/{{target_output_name}}{{output_extension}}"
      }
      if (invoker.toolchain_os == "mac") {
        command = "$ld {{ldflags}} -o \"$unstripped_outfile\" -Wl,-filelist,\"$rspfile\" {{solibs}} {{libs}}"
        rspfile_content = "{{inputs_newline}}"
      } else {
        command = "$ld {{ldflags}} -o \"$unstripped_outfile\" -Wl,--Map=\"$unstripped_outfile.map\" -Wl,--start-group @\"$rspfile\" {{solibs}} -Wl,--end-group {{libs}}"
        rspfile_content = "{{inputs}}"
      }
      if (use_strip) {
        if (invoker.toolchain_os == "mac") {
          command += " && $strip \"$unstripped_outfile\" -o \"$outfile\""
        } else {
          command += " && " + "$strip --strip-sections" +
                     " \"$unstripped_outfile\" \"$outfile\""

          command +=
              " && $buildidtool -build-id-dir .build-id" +
              " -stamp \"$outfile.build-id.stamp\"" + " -entry \"=$outfile\"" +
              " -entry \".debug=$unstripped_outfile\""
        }
      }
      description = "LINK $outfile"
      default_output_dir = "{{root_out_dir}}"
      outputs = [
        outfile,
      ]
      if (outfile != unstripped_outfile) {
        outputs += [ unstripped_outfile ]
      }
    }

    tool("stamp") {
      command = stamp_command
      description = stamp_description
    }

    tool("copy") {
      command = copy_command
      description = copy_description
    }

    # When invoking this toolchain not as the default one, these args will be
    # passed to the build. They are ignored when this is the default toolchain.
    toolchain_args = {
      current_cpu = invoker.toolchain_cpu
      current_os = invoker.toolchain_os

      # These values need to be passed through unchanged.
      target_os = target_os
      target_cpu = target_cpu

      if (defined(invoker.toolchain_args)) {
        # The invoker isn't allowed to fiddle with the essential settings.
        forward_variables_from(invoker.toolchain_args,
                               "*",
                               [
                                 "current_cpu",
                                 "current_os",
                                 "target_os",
                                 "target_cpu",
                               ])
      }
    }
  }
}