llvm/utils/gn/build/toolchain/BUILD.gn - llvm-project - Git at Google

 import("//llvm/utils/gn/build/toolchain/compiler.gni")

 declare_args() {
   # If is_goma is true, the location of the goma client install.
   # Set this to the output of `goma_ctl goma_dir`.
   if (host_os == "win") {
     goma_dir = "C:/src/goma/goma-win64"
   } else {
     goma_dir = getenv("HOME") + "/goma"
   }
 }

 assert(!use_goma || goma_dir != "",
        "set goma_dir to the output of `goma_ctl goma_dir` in your args.gn")

 template("unix_toolchain") {
   toolchain(target_name) {
     # https://groups.google.com/a/chromium.org/d/msg/gn-dev/F_lv5T-tNDM
     forward_variables_from(invoker.toolchain_args, "*")
     not_needed("*")

     forward_variables_from(invoker, "*")

     cc = "cc"
     cxx = "c++"

     if (clang_base_path != "") {
       cc = rebase_path(clang_base_path, root_build_dir) + "/bin/clang"
       cxx = rebase_path(clang_base_path, root_build_dir) + "/bin/clang++"
     }

     ld = cxx  # Don't use goma wrapper for linking.
     if (use_goma) {
       cc = "$goma_dir/gomacc $cc"
       cxx = "$goma_dir/gomacc $cxx"
     }

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

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

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

     tool("alink") {
       if (current_os == "ios" || current_os == "mac") {
         command = "libtool -D -static -no_warning_for_no_symbols {{arflags}} -o {{output}} {{inputs}}"
       } else {
         # Remove the output file first so that ar doesn't try to modify the
         # existing file.
         command =
             "rm -f {{output}} && $ar rcsD {{arflags}} {{output}} {{inputs}}"
       }
       description = "AR {{output}}"
       outputs = [ "{{output_dir}}/{{target_output_name}}.a" ]
       output_prefix = "lib"
       default_output_dir = "{{root_out_dir}}/lib"
     }

     if (current_os == "ios" || current_os == "mac") {
       # gn < 1693 (e214b5d35898) doesn't support |frameworks|, requiring
       # frameworks to be listed in |libs|, but gn >= 1808 (3028c6a426a4) forbids
       # frameworks from appearing in |libs|. This assertion provides a helpful
       # cue to upgrade, and is much more user-friendly than the failure that
       # occurs when an older gn encounters |frameworks|.
       #
       # gn_version doesn’t actually exist in gn < 1709 (52cb644a3fb4), and
       # defined(gn_version) doesn't actually work as expected
       # (https://crbug.com/gn/183), so 1709 is the true minimum enforced by
       # this construct, and if gn_version is not available, this line will still
       # be blamed, making the resolution somewhat discoverable.
       assert(gn_version >= 1693,
              "Your GN is too old! " +
                  "Update it, perhaps by running llvm/utils/gn/get.py")
     }

     tool("solink") {
       outfile = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
       if (current_os == "ios" || current_os == "mac") {
         command = "$ld -shared {{ldflags}} -o $outfile {{inputs}} {{libs}} {{frameworks}}"
         default_output_extension = ".dylib"
       } else {
         command = "$ld -shared {{ldflags}} -Wl,-z,defs -Wl,-soname,{{target_output_name}}{{output_extension}} -o $outfile {{inputs}} {{libs}}"
         default_output_extension = ".so"
       }
       description = "SOLINK $outfile"
       outputs = [ outfile ]
       lib_switch = "-l"
       output_prefix = "lib"
       default_output_dir = "{{root_out_dir}}/lib"
     }

     tool("solink_module") {
       outfile = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
       if (current_os == "ios" || current_os == "mac") {
         command = "$ld -shared {{ldflags}} -Wl,-flat_namespace -Wl,-undefined,suppress -o $outfile {{inputs}} {{libs}} {{frameworks}}"
         default_output_extension = ".dylib"
       } else {
         command = "$ld -shared {{ldflags}} -Wl,-soname,{{target_output_name}}{{output_extension}} -o $outfile {{inputs}} {{libs}}"
         default_output_extension = ".so"
       }
       description = "SOLINK $outfile"
       outputs = [ outfile ]
       lib_switch = "-l"
       default_output_dir = "{{root_out_dir}}/lib"
     }

     tool("link") {
       outfile = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
       if (current_os == "ios" || current_os == "mac") {
         command =
             "$ld {{ldflags}} -o $outfile {{inputs}} {{libs}} {{frameworks}}"
       } else {
         command = "$ld {{ldflags}} -o $outfile -Wl,--start-group {{inputs}} -Wl,--end-group {{libs}}"
       }
       description = "LINK $outfile"
       outputs = [ outfile ]
       lib_switch = "-l"

       # Setting this allows targets to override the default executable output by
       # setting output_dir.
       default_output_dir = "{{root_out_dir}}/bin"
     }

     copy_command = "ln -f {{source}} {{output}} 2>/dev/null || (rm -rf {{output}} && cp -af {{source}} {{output}})"
     tool("copy") {
       command = copy_command
       description = "COPY {{source}} {{output}}"
     }

     if (current_os == "ios" || current_os == "mac") {
       tool("copy_bundle_data") {
         # https://github.com/nico/hack/blob/master/notes/copydir.md
         _copydir = "cd {{source}} && " +
                    "find . | cpio -pdl \"\$OLDPWD\"/{{output}} 2>/dev/null"
         command = "rm -rf {{output}} && if [[ -d {{source}} ]]; then " +
                   _copydir + "; else " + copy_command + "; fi"
         description = "COPY_BUNDLE_DATA {{source}} {{output}}"
       }
       tool("compile_xcassets") {
         command = "false"
         description = "The LLVM build doesn't use any xcasset files"
       }
     }

     tool("stamp") {
       command = "touch {{output}}"
       description = "STAMP {{output}}"
     }
   }
 }

 unix_toolchain("unix") {
   if (current_os != "ios" && current_os != "mac") {
     ar = "ar"
   }

   toolchain_args = {
     current_os = host_os
     current_cpu = host_cpu
   }
 }

 # This template defines a toolchain that uses just-built clang and lld
 # as compiler and linker.
 template("stage2_unix_toolchain") {
   unix_toolchain(target_name) {
     toolchain_args = {
       forward_variables_from(invoker.toolchain_args, "*")

       clang_base_path = root_build_dir
       use_goma = false
     }

     deps = [
       "//:clang($host_toolchain)",
       "//:lld($host_toolchain)",
     ]
     if (current_os != "ios" && current_os != "mac") {
       ar = "bin/llvm-ar"
       deps += [ "//:llvm-ar($host_toolchain)" ]
     }
   }
 }

 stage2_unix_toolchain("stage2_unix") {
   toolchain_args = {
     current_os = host_os
     current_cpu = host_cpu
   }
 }

 if (android_ndk_path != "") {
   stage2_unix_toolchain("stage2_android_aarch64") {
     toolchain_args = {
       current_os = "android"
       current_cpu = "arm64"
     }
   }

   stage2_unix_toolchain("stage2_android_arm") {
     toolchain_args = {
       current_os = "android"
       current_cpu = "arm"
     }
   }
 }

 if (host_os == "mac") {
   stage2_unix_toolchain("stage2_ios_aarch64") {
     toolchain_args = {
       current_os = "ios"
       current_cpu = "arm64"
     }
   }

   stage2_unix_toolchain("stage2_iossim_x64") {
     toolchain_args = {
       current_os = "ios"
       current_cpu = "x64"
     }
   }
 }

 template("win_toolchain") {
   toolchain(target_name) {
     # https://groups.google.com/a/chromium.org/d/msg/gn-dev/F_lv5T-tNDM
     forward_variables_from(invoker.toolchain_args, "*")
     not_needed("*")

     forward_variables_from(invoker, "*")

     cl = "cl"
     link = "link"

     if (clang_base_path != "") {
       cl = rebase_path(clang_base_path, root_build_dir) + "/bin/clang-cl"
       if (use_lld) {
         link = rebase_path(clang_base_path, root_build_dir) + "/bin/lld-link"
       }
     }

     if (use_goma) {
       cl = "$goma_dir/gomacc $cl"
     }

     tool("cc") {
       command = "$cl /nologo /showIncludes /Fo{{output}} /c {{source}} {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}}"
       depsformat = "msvc"
       description = "CC {{output}}"
       outputs = [ "{{source_out_dir}}/{{label_name}}.{{source_name_part}}.obj" ]
     }

     tool("cxx") {
       command = "$cl /nologo /showIncludes /Fo{{output}} /c {{source}} {{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}}"
       depsformat = "msvc"
       description = "CXX {{output}}"
       outputs = [ "{{source_out_dir}}/{{label_name}}.{{source_name_part}}.obj" ]
     }

     tool("alink") {
       command = "$link /lib /nologo {{arflags}} /out:{{output}} {{inputs}}"
       description = "LIB {{output}}"
       outputs = [ "{{output_dir}}/{{target_output_name}}.lib" ]
       default_output_dir = "{{root_out_dir}}/lib"
     }

     tool("solink") {
       outprefix = "{{output_dir}}/{{target_output_name}}"
       dllfile = "$outprefix{{output_extension}}"
       libfile = "$outprefix.lib"
       pdbfile = "$outprefix.pdb"
       command = "$link /nologo /dll {{ldflags}} /out:$dllfile /implib:$libfile /pdb:$pdbfile {{inputs}} {{libs}} "
       description = "LINK $dllfile"
       link_output = libfile
       depend_output = libfile
       runtime_outputs = [ dllfile ]
       outputs = [
         dllfile,
         libfile,
       ]
       lib_switch = ""
       default_output_extension = ".dll"
       restat = true

       # Put dlls next to the executables in bin/ on Windows, since Windows
       # doesn't have a configurable rpath. This matches initialization of
       # module_dir to bin/ in AddLLVM.cmake's set_output_directory().
       default_output_dir = "{{root_out_dir}}/bin"
     }

     # Plugins for opt and clang and so on don't work in LLVM's Windows build
     # since the code doesn't have export annotations, but there are a few
     # standalone loadable modules used for unit-testing LLVM's dynamic library
     # loading code.
     tool("solink_module") {
       outprefix = "{{output_dir}}/{{target_output_name}}"
       dllfile = "$outprefix{{output_extension}}"
       pdbfile = "$outprefix.pdb"
       command = "$link /nologo /dll {{ldflags}} /out:$dllfile /pdb:$pdbfile {{inputs}} {{libs}} "
       description = "LINK_MODULE $dllfile"
       outputs = [ dllfile ]
       lib_switch = ""
       runtime_outputs = outputs
       default_output_extension = ".dll"

       # No default_output_dir, all clients set output_dir.
     }

     tool("link") {
       outprefix = "{{output_dir}}/{{target_output_name}}"
       outfile = "$outprefix{{output_extension}}"
       pdbfile = "$outprefix.pdb"
       command = "$link /nologo {{ldflags}} /out:$outfile /pdb:$pdbfile {{inputs}} {{libs}}"
       description = "LINK $outfile"
       outputs = [ outfile ]
       lib_switch = ""
       default_output_extension = ".exe"

       # Setting this allows targets to override the default executable output by
       # setting output_dir.
       default_output_dir = "{{root_out_dir}}/bin"
     }

     tool("copy") {
       # GN hands out slash-using paths, but cmd's copy needs backslashes.
       # Use cmd's %foo:a=b% substitution feature to convert.
       command = "cmd /c set source=\"{{source}}\" & set output=\"{{output}}\" & call copy /Y %source:/=\% %output:\=/% > nul"
       description = "COPY {{source}} {{output}}"
     }

     tool("stamp") {
       command = "cmd /c type nul > {{output}}"
       description = "STAMP {{output}}"
     }
   }
 }

 win_toolchain("win") {
   toolchain_args = {
     current_os = "win"
     current_cpu = host_cpu
   }
 }

 win_toolchain("stage2_win") {
   toolchain_args = {
     current_os = host_os
     current_cpu = host_cpu

     clang_base_path = root_build_dir
     use_goma = false
   }
   deps = [
     "//:clang($host_toolchain)",
     "//:lld($host_toolchain)",
   ]
 }
	import("//llvm/utils/gn/build/toolchain/compiler.gni")

	declare_args() {
	# If is_goma is true, the location of the goma client install.
	# Set this to the output of `goma_ctl goma_dir`.
	if (host_os == "win") {
	goma_dir = "C:/src/goma/goma-win64"
	} else {
	goma_dir = getenv("HOME") + "/goma"
	}
	}

	assert(!use_goma \|\| goma_dir != "",
	"set goma_dir to the output of `goma_ctl goma_dir` in your args.gn")

	template("unix_toolchain") {
	toolchain(target_name) {
	# https://groups.google.com/a/chromium.org/d/msg/gn-dev/F_lv5T-tNDM
	forward_variables_from(invoker.toolchain_args, "*")
	not_needed("*")

	forward_variables_from(invoker, "*")

	cc = "cc"
	cxx = "c++"

	if (clang_base_path != "") {
	cc = rebase_path(clang_base_path, root_build_dir) + "/bin/clang"
	cxx = rebase_path(clang_base_path, root_build_dir) + "/bin/clang++"
	}

	ld = cxx # Don't use goma wrapper for linking.
	if (use_goma) {
	cc = "$goma_dir/gomacc $cc"
	cxx = "$goma_dir/gomacc $cxx"
	}

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

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

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

	tool("alink") {
	if (current_os == "ios" \|\| current_os == "mac") {
	command = "libtool -D -static -no_warning_for_no_symbols {{arflags}} -o {{output}} {{inputs}}"
	} else {
	# Remove the output file first so that ar doesn't try to modify the
	# existing file.
	command =
	"rm -f {{output}} && $ar rcsD {{arflags}} {{output}} {{inputs}}"
	}
	description = "AR {{output}}"
	outputs = [ "{{output_dir}}/{{target_output_name}}.a" ]
	output_prefix = "lib"
	default_output_dir = "{{root_out_dir}}/lib"
	}

	if (current_os == "ios" \|\| current_os == "mac") {
	# gn < 1693 (e214b5d35898) doesn't support \|frameworks\|, requiring
	# frameworks to be listed in \|libs\|, but gn >= 1808 (3028c6a426a4) forbids
	# frameworks from appearing in \|libs\|. This assertion provides a helpful
	# cue to upgrade, and is much more user-friendly than the failure that
	# occurs when an older gn encounters \|frameworks\|.
	#
	# gn_version doesn’t actually exist in gn < 1709 (52cb644a3fb4), and
	# defined(gn_version) doesn't actually work as expected
	# (https://crbug.com/gn/183), so 1709 is the true minimum enforced by
	# this construct, and if gn_version is not available, this line will still
	# be blamed, making the resolution somewhat discoverable.
	assert(gn_version >= 1693,
	"Your GN is too old! " +
	"Update it, perhaps by running llvm/utils/gn/get.py")
	}

	tool("solink") {
	outfile = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
	if (current_os == "ios" \|\| current_os == "mac") {
	command = "$ld -shared {{ldflags}} -o $outfile {{inputs}} {{libs}} {{frameworks}}"
	default_output_extension = ".dylib"
	} else {
	command = "$ld -shared {{ldflags}} -Wl,-z,defs -Wl,-soname,{{target_output_name}}{{output_extension}} -o $outfile {{inputs}} {{libs}}"
	default_output_extension = ".so"
	}
	description = "SOLINK $outfile"
	outputs = [ outfile ]
	lib_switch = "-l"
	output_prefix = "lib"
	default_output_dir = "{{root_out_dir}}/lib"
	}

	tool("solink_module") {
	outfile = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
	if (current_os == "ios" \|\| current_os == "mac") {
	command = "$ld -shared {{ldflags}} -Wl,-flat_namespace -Wl,-undefined,suppress -o $outfile {{inputs}} {{libs}} {{frameworks}}"
	default_output_extension = ".dylib"
	} else {
	command = "$ld -shared {{ldflags}} -Wl,-soname,{{target_output_name}}{{output_extension}} -o $outfile {{inputs}} {{libs}}"
	default_output_extension = ".so"
	}
	description = "SOLINK $outfile"
	outputs = [ outfile ]
	lib_switch = "-l"
	default_output_dir = "{{root_out_dir}}/lib"
	}

	tool("link") {
	outfile = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
	if (current_os == "ios" \|\| current_os == "mac") {
	command =
	"$ld {{ldflags}} -o $outfile {{inputs}} {{libs}} {{frameworks}}"
	} else {
	command = "$ld {{ldflags}} -o $outfile -Wl,--start-group {{inputs}} -Wl,--end-group {{libs}}"
	}
	description = "LINK $outfile"
	outputs = [ outfile ]
	lib_switch = "-l"

	# Setting this allows targets to override the default executable output by
	# setting output_dir.
	default_output_dir = "{{root_out_dir}}/bin"
	}

	copy_command = "ln -f {{source}} {{output}} 2>/dev/null \|\| (rm -rf {{output}} && cp -af {{source}} {{output}})"
	tool("copy") {
	command = copy_command
	description = "COPY {{source}} {{output}}"
	}

	if (current_os == "ios" \|\| current_os == "mac") {
	tool("copy_bundle_data") {
	# https://github.com/nico/hack/blob/master/notes/copydir.md
	_copydir = "cd {{source}} && " +
	"find . \| cpio -pdl \"\$OLDPWD\"/{{output}} 2>/dev/null"
	command = "rm -rf {{output}} && if [[ -d {{source}} ]]; then " +
	_copydir + "; else " + copy_command + "; fi"
	description = "COPY_BUNDLE_DATA {{source}} {{output}}"
	}
	tool("compile_xcassets") {
	command = "false"
	description = "The LLVM build doesn't use any xcasset files"
	}
	}

	tool("stamp") {
	command = "touch {{output}}"
	description = "STAMP {{output}}"
	}
	}
	}

	unix_toolchain("unix") {
	if (current_os != "ios" && current_os != "mac") {
	ar = "ar"
	}

	toolchain_args = {
	current_os = host_os
	current_cpu = host_cpu
	}
	}

	# This template defines a toolchain that uses just-built clang and lld
	# as compiler and linker.
	template("stage2_unix_toolchain") {
	unix_toolchain(target_name) {
	toolchain_args = {
	forward_variables_from(invoker.toolchain_args, "*")

	clang_base_path = root_build_dir
	use_goma = false
	}

	deps = [
	"//:clang($host_toolchain)",
	"//:lld($host_toolchain)",
	]
	if (current_os != "ios" && current_os != "mac") {
	ar = "bin/llvm-ar"
	deps += [ "//:llvm-ar($host_toolchain)" ]
	}
	}
	}

	stage2_unix_toolchain("stage2_unix") {
	toolchain_args = {
	current_os = host_os
	current_cpu = host_cpu
	}
	}

	if (android_ndk_path != "") {
	stage2_unix_toolchain("stage2_android_aarch64") {
	toolchain_args = {
	current_os = "android"
	current_cpu = "arm64"
	}
	}

	stage2_unix_toolchain("stage2_android_arm") {
	toolchain_args = {
	current_os = "android"
	current_cpu = "arm"
	}
	}
	}

	if (host_os == "mac") {
	stage2_unix_toolchain("stage2_ios_aarch64") {
	toolchain_args = {
	current_os = "ios"
	current_cpu = "arm64"
	}
	}

	stage2_unix_toolchain("stage2_iossim_x64") {
	toolchain_args = {
	current_os = "ios"
	current_cpu = "x64"
	}
	}
	}

	template("win_toolchain") {
	toolchain(target_name) {
	# https://groups.google.com/a/chromium.org/d/msg/gn-dev/F_lv5T-tNDM
	forward_variables_from(invoker.toolchain_args, "*")
	not_needed("*")

	forward_variables_from(invoker, "*")

	cl = "cl"
	link = "link"

	if (clang_base_path != "") {
	cl = rebase_path(clang_base_path, root_build_dir) + "/bin/clang-cl"
	if (use_lld) {
	link = rebase_path(clang_base_path, root_build_dir) + "/bin/lld-link"
	}
	}

	if (use_goma) {
	cl = "$goma_dir/gomacc $cl"
	}

	tool("cc") {
	command = "$cl /nologo /showIncludes /Fo{{output}} /c {{source}} {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}}"
	depsformat = "msvc"
	description = "CC {{output}}"
	outputs = [ "{{source_out_dir}}/{{label_name}}.{{source_name_part}}.obj" ]
	}

	tool("cxx") {
	command = "$cl /nologo /showIncludes /Fo{{output}} /c {{source}} {{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}}"
	depsformat = "msvc"
	description = "CXX {{output}}"
	outputs = [ "{{source_out_dir}}/{{label_name}}.{{source_name_part}}.obj" ]
	}

	tool("alink") {
	command = "$link /lib /nologo {{arflags}} /out:{{output}} {{inputs}}"
	description = "LIB {{output}}"
	outputs = [ "{{output_dir}}/{{target_output_name}}.lib" ]
	default_output_dir = "{{root_out_dir}}/lib"
	}

	tool("solink") {
	outprefix = "{{output_dir}}/{{target_output_name}}"
	dllfile = "$outprefix{{output_extension}}"
	libfile = "$outprefix.lib"
	pdbfile = "$outprefix.pdb"
	command = "$link /nologo /dll {{ldflags}} /out:$dllfile /implib:$libfile /pdb:$pdbfile {{inputs}} {{libs}} "
	description = "LINK $dllfile"
	link_output = libfile
	depend_output = libfile
	runtime_outputs = [ dllfile ]
	outputs = [
	dllfile,
	libfile,
	]
	lib_switch = ""
	default_output_extension = ".dll"
	restat = true

	# Put dlls next to the executables in bin/ on Windows, since Windows
	# doesn't have a configurable rpath. This matches initialization of
	# module_dir to bin/ in AddLLVM.cmake's set_output_directory().
	default_output_dir = "{{root_out_dir}}/bin"
	}

	# Plugins for opt and clang and so on don't work in LLVM's Windows build
	# since the code doesn't have export annotations, but there are a few
	# standalone loadable modules used for unit-testing LLVM's dynamic library
	# loading code.
	tool("solink_module") {
	outprefix = "{{output_dir}}/{{target_output_name}}"
	dllfile = "$outprefix{{output_extension}}"
	pdbfile = "$outprefix.pdb"
	command = "$link /nologo /dll {{ldflags}} /out:$dllfile /pdb:$pdbfile {{inputs}} {{libs}} "
	description = "LINK_MODULE $dllfile"
	outputs = [ dllfile ]
	lib_switch = ""
	runtime_outputs = outputs
	default_output_extension = ".dll"

	# No default_output_dir, all clients set output_dir.
	}

	tool("link") {
	outprefix = "{{output_dir}}/{{target_output_name}}"
	outfile = "$outprefix{{output_extension}}"
	pdbfile = "$outprefix.pdb"
	command = "$link /nologo {{ldflags}} /out:$outfile /pdb:$pdbfile {{inputs}} {{libs}}"
	description = "LINK $outfile"
	outputs = [ outfile ]
	lib_switch = ""
	default_output_extension = ".exe"

	# Setting this allows targets to override the default executable output by
	# setting output_dir.
	default_output_dir = "{{root_out_dir}}/bin"
	}

	tool("copy") {
	# GN hands out slash-using paths, but cmd's copy needs backslashes.
	# Use cmd's %foo:a=b% substitution feature to convert.
	command = "cmd /c set source=\"{{source}}\" & set output=\"{{output}}\" & call copy /Y %source:/=\% %output:\=/% > nul"
	description = "COPY {{source}} {{output}}"
	}

	tool("stamp") {
	command = "cmd /c type nul > {{output}}"
	description = "STAMP {{output}}"
	}
	}
	}

	win_toolchain("win") {
	toolchain_args = {
	current_os = "win"
	current_cpu = host_cpu
	}
	}

	win_toolchain("stage2_win") {
	toolchain_args = {
	current_os = host_os
	current_cpu = host_cpu

	clang_base_path = root_build_dir
	use_goma = false
	}
	deps = [
	"//:clang($host_toolchain)",
	"//:lld($host_toolchain)",
	]
	}