gn/BUILD.gn - platform/external/skqp - Gitiles

 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

 declare_args() {
   ar = "ar"
   cc = "cc"
   cxx = "c++"

   if (is_android) {
     if (host_os == "win") {
       ar = "$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin/ar.exe"
       cc = "$ndk/toolchains/llvm/prebuilt/$ndk_host/bin/clang.exe"
       cxx = "$ndk/toolchains/llvm/prebuilt/$ndk_host/bin/clang++.exe"
     } else {
       ar = "$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin/ar"
       cc = "$ndk/toolchains/llvm/prebuilt/$ndk_host/bin/clang"
       cxx = "$ndk/toolchains/llvm/prebuilt/$ndk_host/bin/clang++"
     }
   }

   windk = "C:/Program Files (x86)/Microsoft Visual Studio 14.0"

   extra_cflags = []
   extra_cflags_c = []
   extra_cflags_cc = []
   extra_ldflags = []

   cc_wrapper = ""
   malloc = ""
 }

 if (host_os == "win") {
   python = "python.bat"
   stamp = "cmd.exe /c echo >"
 } else {
   python = "python"
   stamp = "touch"
 }

 is_clang = is_android || is_ios || is_mac || (cc == "clang" && cxx == "clang++")
 if (!is_clang && !is_win) {
   is_clang = exec_script("is_clang.py",
                          [
                            cc,
                            cxx,
                          ],
                          "value")
 }

 if (is_ios) {
   ios_sysroot = exec_script("find_ios_sysroot.py", [], "trim string")
 }

 config("default") {
   asmflags = []
   cflags = []
   cflags_c = []
   cflags_cc = []
   defines = []
   ldflags = []
   libs = []

   if (is_win) {
     cflags += [
       "/FS",  # Preserve previous PDB behavior.
       "/bigobj",  # Some of our files are bigger than the regular limits.
       "/WX",  # Treat warnings as errors.
     ]
     defines += [
       "_CRT_SECURE_NO_WARNINGS",  # Disables warnings about sscanf().
       "_HAS_EXCEPTIONS=0",  # Disables exceptions in MSVC STL.
       "WIN32_LEAN_AND_MEAN",
       "NOMINMAX",
     ]
     include_dirs = [
       "$windk/VC/include",

       # For local builds.
       "$windk/../Windows Kits/10/Include/10.0.10150.0/ucrt",
       "$windk/../Windows Kits/8.1/Include/shared",
       "$windk/../Windows Kits/8.1/Include/um",

       # For builds using win_toolchain asset.
       "$windk/win_sdk/Include/10.0.10586.0/shared",
       "$windk/win_sdk/Include/10.0.10586.0/ucrt",
       "$windk/win_sdk/Include/10.0.10586.0/um",
     ]
     lib_dirs = [
       # For local builds.
       "$windk/../Windows Kits/10/Lib/10.0.10150.0/ucrt/$target_cpu",
       "$windk/../Windows Kits/8.1/Lib/winv6.3/um/$target_cpu",

       # For builds using win_toolchain asset.
       "$windk/win_sdk/Lib/10.0.10586.0/ucrt/$target_cpu",
       "$windk/win_sdk/Lib/10.0.10586.0/um/$target_cpu",
     ]
     if (target_cpu == "x86") {
       lib_dirs += [ "$windk/VC/lib" ]
     } else {
       lib_dirs += [ "$windk/VC/lib/amd64" ]
     }
   } else {
     cflags += [
       "-fstrict-aliasing",
       "-fPIC",
       "-fvisibility=hidden",
       "-Werror",
     ]
     cflags_cc += [
       "-std=c++11",
       "-fno-threadsafe-statics",
       "-fvisibility-inlines-hidden",
     ]
   }

   if (current_cpu == "arm") {
     cflags += [
       "-march=armv7-a",
       "-mfpu=neon",
       "-mthumb",
     ]
   } else if (current_cpu == "mipsel") {
     cflags += [
       "-march=mips32r2",
       "-mdspr2",
     ]
   } else if (current_cpu == "x86" && !is_win) {
     asmflags += [ "-m32" ]
     cflags += [
       "-m32",
       "-msse2",
       "-mfpmath=sse",
     ]
     ldflags += [ "-m32" ]
   }

   if (malloc != "" && !is_win) {
     cflags += [
       "-fno-builtin-malloc",
       "-fno-builtin-calloc",
       "-fno-builtin-realloc",
       "-fno-builtin-free",
     ]
     libs += [ malloc ]
   }

   if (is_android) {
     asmflags += [
       "--target=$ndk_target",
       "-B$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin",
     ]
     cflags += [
       "--sysroot=$ndk/platforms/$ndk_platform",
       "--target=$ndk_target",
       "-B$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin",
     ]
     cflags_cc += [
       "-isystem$ndk/sources/android/support/include",
       "-isystem$ndk/sources/cxx-stl/gnu-libstdc++/4.9/include",
       "-isystem$ndk/sources/cxx-stl/gnu-libstdc++/4.9/libs/$ndk_stdlib/include",
     ]
     ldflags += [
       "--sysroot=$ndk/platforms/$ndk_platform",
       "--target=$ndk_target",
       "-B$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin",
     ]
     lib_dirs = [
       "$ndk/sources/cxx-stl/gnu-libstdc++/4.9/libs/$ndk_stdlib",
       "$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/lib/gcc/$ndk_target/4.9.x",
     ]

     if (current_cpu == "mips64el") {
       # The r13 NDK omits /usr/lib from the MIPS64 sysroots, but Clang searches
       # for /usr/lib64 as $PATH_TO_USR_LIB/../lib64.  If there's no /usr/lib,
       # it can't find /usr/lib64.  We must point Clang at /usr/lib64 manually.
       lib_dirs += [ "$ndk/platforms/$ndk_platform/usr/lib64" ]
       ldflags += [ "-B$ndk/platforms/$ndk_platform/usr/lib64" ]
     }

     libs += [ "gnustl_static" ]
   }

   if (is_ios) {
     cflags += [
       "-isysroot",
       ios_sysroot,
       "-arch",
       target_cpu,
     ]
     cflags_cc += [ "-stdlib=libc++" ]
     ldflags += [
       "-isysroot",
       ios_sysroot,
       "-arch",
       target_cpu,
       "-stdlib=libc++",
     ]
     libs += [ "objc" ]

     # We used to link all our iOS tools together, so none actually defines main().
     # Instead they each define their own entry point, which our iOS mega-app called.
     # If we can we'd like to not do that anymore.  While we're building both ways, here's
     # our clever hack to give each tool back its own main().
     cflags += [
       "-Ddm_main=main",
       "-Dnanobench_main=main",
       "-Dtool_main=main",
       "-Dtest_main=main",
     ]
   }

   if (is_linux) {
     libs += [ "pthread" ]
   }

   if (sanitize != "") {
     # You can either pass the sanitizers directly, e.g. "address,undefined",
     # or pass one of the couple common aliases used by the bots.
     sanitizers = sanitize
     if (sanitize == "ASAN") {
       sanitizers = "address,bool,function,integer-divide-by-zero,nonnull-attribute,null,object-size,return,returns-nonnull-attribute,shift,signed-integer-overflow,unreachable,vla-bound,vptr"
     } else if (sanitize == "TSAN") {
       sanitizers = "thread"
     } else if (sanitize == "MSAN") {
       sanitizers = "memory"
     }

     cflags += [
       "-fsanitize=$sanitizers",
       "-fno-sanitize-recover=$sanitizers",
       "-fsanitize-blacklist=" + rebase_path("../tools/xsan.blacklist"),
     ]
     ldflags += [ "-fsanitize=$sanitizers" ]
     if (sanitizers == "memory") {
       cflags += [ "-fsanitize-memory-track-origins" ]
       cflags_cc += [ "-stdlib=libc++" ]
       ldflags += [ "-stdlib=libc++" ]
     }
   }
 }

 config("no_exceptions") {
   # Exceptions are disabled by default on Windows.  (Use /EHsc to enable them.)
   if (!is_win) {
     cflags_cc = [ "-fno-exceptions" ]
   }
 }

 config("warnings") {
   cflags = []
   cflags_cc = []
   cflags_objc = []
   if (is_win) {
     cflags += [
       "/W3",  # Turn on lots of warnings.

       # Disable a bunch of warnings:
       "/wd4244",  # conversion from 'float' to 'int', possible loss of data
       "/wd4267",  # conversion from 'size_t' to 'int', possible loss of data
       "/wd4800",  # forcing value to bool 'true' or 'false' (performance warning)

       # Probably only triggers when /EHsc is enabled.
       "/wd4291",  # no matching operator delete found;
                   # memory will not be freed if initialization throws an exception
     ]
   } else {
     cflags += [
       "-Wall",
       "-Wextra",
       "-Winit-self",
       "-Wpointer-arith",
       "-Wsign-compare",
       "-Wvla",

       "-Wno-deprecated-declarations",
       "-Wno-maybe-uninitialized",
     ]
     cflags_cc += [ "-Wnon-virtual-dtor" ]

     if (is_clang) {
       cflags += [
         "-Weverything",
         "-Wno-unknown-warning-option",  # Let older Clangs ignore newer Clangs' warnings.
       ]

       if (is_android && target_cpu == "x86") {
         # Clang seems to think new/malloc will only be 4-byte aligned on x86 Android.
         # We're pretty sure it's actually 8-byte alignment.
         cflags += [ "-Wno-over-aligned" ]
       }

       cflags += [
         "-Wno-cast-align",
         "-Wno-conditional-uninitialized",
         "-Wno-conversion",
         "-Wno-disabled-macro-expansion",
         "-Wno-documentation",
         "-Wno-documentation-unknown-command",
         "-Wno-double-promotion",
         "-Wno-exit-time-destructors",  # TODO: OK outside libskia
         "-Wno-float-conversion",
         "-Wno-float-equal",
         "-Wno-format-nonliteral",
         "-Wno-global-constructors",  # TODO: OK outside libskia
         "-Wno-gnu-zero-variadic-macro-arguments",
         "-Wno-missing-prototypes",
         "-Wno-missing-variable-declarations",
         "-Wno-pedantic",
         "-Wno-reserved-id-macro",
         "-Wno-shadow",
         "-Wno-shift-sign-overflow",
         "-Wno-sign-conversion",
         "-Wno-switch-enum",
         "-Wno-undef",
         "-Wno-unreachable-code",
         "-Wno-unreachable-code-break",
         "-Wno-unreachable-code-return",
         "-Wno-unused-macros",
         "-Wno-unused-member-function",
       ]
       cflags_cc += [
         "-Wno-abstract-vbase-init",
         "-Wno-weak-vtables",
       ]

       # We are unlikely to want to fix these.
       cflags += [
         "-Wno-covered-switch-default",
         "-Wno-deprecated",
         "-Wno-implicit-fallthrough",
         "-Wno-missing-noreturn",
         "-Wno-old-style-cast",
         "-Wno-padded",
       ]
       cflags_cc += [
         "-Wno-c++98-compat",
         "-Wno-c++98-compat-pedantic",
         "-Wno-undefined-func-template",
       ]
       cflags_objc += [
         "-Wno-direct-ivar-access",
         "-Wno-objc-interface-ivars",
       ]
     }
   }
 }
 config("warnings_except_public_headers") {
   if (!is_win) {
     cflags = [ "-Wno-unused-parameter" ]
   }
 }

 config("extra_flags") {
   cflags = extra_cflags
   cflags_c = extra_cflags_c
   cflags_cc = extra_cflags_cc
   ldflags = extra_ldflags
 }

 config("debug_symbols") {
   # It's annoying to wait for full debug symbols to push over
   # to Android devices.  -gline-tables-only is a lot slimmer.
   if (is_android) {
     cflags = [ "-gline-tables-only" ]
   } else if (is_win) {
     cflags = [ "/Zi" ]
     ldflags = [ "/DEBUG" ]
   } else {
     cflags = [ "-g" ]
   }
 }

 config("no_rtti") {
   if (sanitize != "ASAN") {  # -fsanitize=vptr requires RTTI
     if (is_win) {
       cflags_cc = [ "/GR-" ]
     } else {
       cflags_cc = [ "-fno-rtti" ]
     }
   }
 }

 config("release") {
   if (is_win) {
     cflags = [
       "/O2",
       "/Zc:inline",
       "/GS-",
     ]
     ldflags = [
       "/OPT:ICF",
       "/OPT:REF",
     ]
   } else {
     cflags = [
       "-O3",
       "-momit-leaf-frame-pointer",
     ]
   }
   defines = [ "NDEBUG" ]
 }

 config("executable") {
   if (is_android) {
     ldflags = [ "-pie" ]
   } else if (is_mac) {
     ldflags = [ "-Wl,-rpath,@loader_path/." ]
   } else if (is_linux) {
     ldflags = [
       "-rdynamic",
       "-Wl,-rpath,\$ORIGIN",
     ]
   } else if (is_win) {
     ldflags = [
       "/SUBSYSTEM:CONSOLE",  # Quiet "no subsystem specified; CONSOLE assumed".
       "/INCREMENTAL:NO",  # Quiet warnings about failing to incrementally link by never trying to.
     ]
   }
 }

 toolchain("msvc") {
   lib_dir_switch = "/LIBPATH:"

   bin = "$windk/VC/bin/amd64"
   env_setup = ""
   if (target_cpu == "x86") {
     bin += "_x86"
     env_setup = "cmd /c $windk/win_sdk/bin/SetEnv.cmd /x86 && "
   }

   tool("cc") {
     rspfile = "{{output}}.rsp"
     precompiled_header_type = "msvc"
     pdbname = "{{target_out_dir}}/{{label_name}}_c.pdb"

     # Label names may have spaces so pdbname must be quoted.
     command = "$env_setup$bin/cl.exe /nologo /showIncludes /FC @$rspfile /c {{source}} /Fo{{output}} /Fd\"$pdbname\""
     depsformat = "msvc"
     outputs = [
       "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.obj",
     ]
     rspfile_content = "{{defines}} {{include_dirs}} {{cflags}} {{cflags_c}}"
     description = "compile {{source}}"
   }

   tool("cxx") {
     rspfile = "{{output}}.rsp"
     precompiled_header_type = "msvc"
     pdbname = "{{target_out_dir}}/{{label_name}}_c.pdb"

     # Label names may have spaces so pdbname must be quoted.
     command = "$env_setup$bin/cl.exe /nologo /showIncludes /FC @$rspfile /c {{source}} /Fo{{output}} /Fd\"$pdbname\""
     depsformat = "msvc"
     outputs = [
       "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.obj",
     ]
     rspfile_content = "{{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}}"
     description = "compile {{source}}"
   }

   tool("alink") {
     rspfile = "{{output}}.rsp"

     command = "$env_setup$bin/lib.exe /nologo /ignore:4221 {{arflags}} /OUT:{{output}} @$rspfile"
     outputs = [
       # Ignore {{output_extension}} and always use .lib, there's no reason to
       # allow targets to override this extension on Windows.
       "{{root_out_dir}}/{{target_output_name}}{{output_extension}}",
     ]
     default_output_extension = ".lib"
     default_output_dir = "{{target_out_dir}}"

     # inputs_newline works around a fixed per-line buffer size in the linker.
     rspfile_content = "{{inputs_newline}}"
     description = "link {{output}}"
   }

   tool("solink") {
     dllname = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
     libname = "${dllname}.lib"
     pdbname = "${dllname}.pdb"
     rspfile = "${dllname}.rsp"

     command = "$env_setup$bin/link.exe /nologo /IMPLIB:$libname /DLL /OUT:$dllname /PDB:$pdbname @$rspfile"
     outputs = [
       dllname,
       libname,
       pdbname,
     ]
     default_output_extension = ".dll"
     default_output_dir = "{{root_out_dir}}"

     link_output = libname
     depend_output = libname
     runtime_outputs = [
       dllname,
       pdbname,
     ]

     # I don't quite understand this.  Aping Chrome's toolchain/win/BUILD.gn.
     restat = true

     # inputs_newline works around a fixed per-line buffer size in the linker.
     rspfile_content = "{{inputs_newline}} {{libs}} {{solibs}} {{ldflags}}"
     description = "link {{output}}"
   }

   tool("link") {
     exename = "{{root_out_dir}}/{{target_output_name}}{{output_extension}}"
     pdbname = "$exename.pdb"
     rspfile = "$exename.rsp"

     command =
         "$env_setup$bin/link.exe /nologo /OUT:$exename /PDB:$pdbname @$rspfile"

     default_output_extension = ".exe"
     default_output_dir = "{{root_out_dir}}"
     outputs = [
       exename,
     ]

     # inputs_newline works around a fixed per-line buffer size in the linker.
     rspfile_content = "{{inputs_newline}} {{libs}} {{solibs}} {{ldflags}}"
     description = "link {{output}}"
   }

   tool("stamp") {
     command = "$stamp {{output}}"
     description = "stamp {{output}}"
   }

   tool("copy") {
     cp_py = rebase_path("cp.py")
     command = "$python $cp_py {{source}} {{output}}"
     description = "copy {{source}} {{output}}"
   }
 }

 toolchain("gcc_like") {
   lib_switch = "-l"
   lib_dir_switch = "-L"

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

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

   tool("objc") {
     depfile = "{{output}}.d"
     command = "$cc_wrapper $cc -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_objc}} -c {{source}} -o {{output}}"
     depsformat = "gcc"
     outputs = [
       "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
     ]
     description = "compile {{source}}"
   }

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

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

   tool("alink") {
     rspfile = "{{output}}.rsp"
     rspfile_content = "{{inputs}}"
     ar_py = rebase_path("ar.py")
     command = "$python $ar_py $ar {{output}} $rspfile"
     outputs = [
       "{{root_out_dir}}/{{target_output_name}}{{output_extension}}",
     ]
     default_output_extension = ".a"
     output_prefix = "lib"
     description = "link {{output}}"
   }

   tool("solink") {
     soname = "{{target_output_name}}{{output_extension}}"

     rpath = "-Wl,-soname,$soname"
     if (is_mac) {
       rpath = "-Wl,-install_name,@rpath/$soname"
     }

     command = "$cc_wrapper $cxx -shared {{ldflags}} {{inputs}} {{solibs}} {{libs}} $rpath -o {{output}}"
     outputs = [
       "{{root_out_dir}}/$soname",
     ]
     output_prefix = "lib"
     default_output_extension = ".so"
     description = "link {{output}}"
   }

   tool("link") {
     command = "$cc_wrapper $cxx {{ldflags}} {{inputs}} {{solibs}} {{libs}} -o {{output}}"
     outputs = [
       "{{root_out_dir}}/{{target_output_name}}{{output_extension}}",
     ]
     description = "link {{output}}"
   }

   tool("stamp") {
     command = "$stamp {{output}}"
     description = "stamp {{output}}"
   }

   tool("copy") {
     cp_py = rebase_path("cp.py")
     command = "$python $cp_py {{source}} {{output}}"
     description = "copy {{source}} {{output}}"
   }
 }
	# Copyright 2016 Google Inc.
	#
	# Use of this source code is governed by a BSD-style license that can be
	# found in the LICENSE file.

	declare_args() {
	ar = "ar"
	cc = "cc"
	cxx = "c++"

	if (is_android) {
	if (host_os == "win") {
	ar = "$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin/ar.exe"
	cc = "$ndk/toolchains/llvm/prebuilt/$ndk_host/bin/clang.exe"
	cxx = "$ndk/toolchains/llvm/prebuilt/$ndk_host/bin/clang++.exe"
	} else {
	ar = "$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin/ar"
	cc = "$ndk/toolchains/llvm/prebuilt/$ndk_host/bin/clang"
	cxx = "$ndk/toolchains/llvm/prebuilt/$ndk_host/bin/clang++"
	}
	}

	windk = "C:/Program Files (x86)/Microsoft Visual Studio 14.0"

	extra_cflags = []
	extra_cflags_c = []
	extra_cflags_cc = []
	extra_ldflags = []

	cc_wrapper = ""
	malloc = ""
	}

	if (host_os == "win") {
	python = "python.bat"
	stamp = "cmd.exe /c echo >"
	} else {
	python = "python"
	stamp = "touch"
	}

	is_clang = is_android \|\| is_ios \|\| is_mac \|\| (cc == "clang" && cxx == "clang++")
	if (!is_clang && !is_win) {
	is_clang = exec_script("is_clang.py",
	[
	cc,
	cxx,
	],
	"value")
	}

	if (is_ios) {
	ios_sysroot = exec_script("find_ios_sysroot.py", [], "trim string")
	}

	config("default") {
	asmflags = []
	cflags = []
	cflags_c = []
	cflags_cc = []
	defines = []
	ldflags = []
	libs = []

	if (is_win) {
	cflags += [
	"/FS", # Preserve previous PDB behavior.
	"/bigobj", # Some of our files are bigger than the regular limits.
	"/WX", # Treat warnings as errors.
	]
	defines += [
	"_CRT_SECURE_NO_WARNINGS", # Disables warnings about sscanf().
	"_HAS_EXCEPTIONS=0", # Disables exceptions in MSVC STL.
	"WIN32_LEAN_AND_MEAN",
	"NOMINMAX",
	]
	include_dirs = [
	"$windk/VC/include",

	# For local builds.
	"$windk/../Windows Kits/10/Include/10.0.10150.0/ucrt",
	"$windk/../Windows Kits/8.1/Include/shared",
	"$windk/../Windows Kits/8.1/Include/um",

	# For builds using win_toolchain asset.
	"$windk/win_sdk/Include/10.0.10586.0/shared",
	"$windk/win_sdk/Include/10.0.10586.0/ucrt",
	"$windk/win_sdk/Include/10.0.10586.0/um",
	]
	lib_dirs = [
	# For local builds.
	"$windk/../Windows Kits/10/Lib/10.0.10150.0/ucrt/$target_cpu",
	"$windk/../Windows Kits/8.1/Lib/winv6.3/um/$target_cpu",

	# For builds using win_toolchain asset.
	"$windk/win_sdk/Lib/10.0.10586.0/ucrt/$target_cpu",
	"$windk/win_sdk/Lib/10.0.10586.0/um/$target_cpu",
	]
	if (target_cpu == "x86") {
	lib_dirs += [ "$windk/VC/lib" ]
	} else {
	lib_dirs += [ "$windk/VC/lib/amd64" ]
	}
	} else {
	cflags += [
	"-fstrict-aliasing",
	"-fPIC",
	"-fvisibility=hidden",
	"-Werror",
	]
	cflags_cc += [
	"-std=c++11",
	"-fno-threadsafe-statics",
	"-fvisibility-inlines-hidden",
	]
	}

	if (current_cpu == "arm") {
	cflags += [
	"-march=armv7-a",
	"-mfpu=neon",
	"-mthumb",
	]
	} else if (current_cpu == "mipsel") {
	cflags += [
	"-march=mips32r2",
	"-mdspr2",
	]
	} else if (current_cpu == "x86" && !is_win) {
	asmflags += [ "-m32" ]
	cflags += [
	"-m32",
	"-msse2",
	"-mfpmath=sse",
	]
	ldflags += [ "-m32" ]
	}

	if (malloc != "" && !is_win) {
	cflags += [
	"-fno-builtin-malloc",
	"-fno-builtin-calloc",
	"-fno-builtin-realloc",
	"-fno-builtin-free",
	]
	libs += [ malloc ]
	}

	if (is_android) {
	asmflags += [
	"--target=$ndk_target",
	"-B$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin",
	]
	cflags += [
	"--sysroot=$ndk/platforms/$ndk_platform",
	"--target=$ndk_target",
	"-B$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin",
	]
	cflags_cc += [
	"-isystem$ndk/sources/android/support/include",
	"-isystem$ndk/sources/cxx-stl/gnu-libstdc++/4.9/include",
	"-isystem$ndk/sources/cxx-stl/gnu-libstdc++/4.9/libs/$ndk_stdlib/include",
	]
	ldflags += [
	"--sysroot=$ndk/platforms/$ndk_platform",
	"--target=$ndk_target",
	"-B$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/$ndk_target/bin",
	]
	lib_dirs = [
	"$ndk/sources/cxx-stl/gnu-libstdc++/4.9/libs/$ndk_stdlib",
	"$ndk/toolchains/$ndk_gccdir-4.9/prebuilt/$ndk_host/lib/gcc/$ndk_target/4.9.x",
	]

	if (current_cpu == "mips64el") {
	# The r13 NDK omits /usr/lib from the MIPS64 sysroots, but Clang searches
	# for /usr/lib64 as $PATH_TO_USR_LIB/../lib64. If there's no /usr/lib,
	# it can't find /usr/lib64. We must point Clang at /usr/lib64 manually.
	lib_dirs += [ "$ndk/platforms/$ndk_platform/usr/lib64" ]
	ldflags += [ "-B$ndk/platforms/$ndk_platform/usr/lib64" ]
	}

	libs += [ "gnustl_static" ]
	}

	if (is_ios) {
	cflags += [
	"-isysroot",
	ios_sysroot,
	"-arch",
	target_cpu,
	]
	cflags_cc += [ "-stdlib=libc++" ]
	ldflags += [
	"-isysroot",
	ios_sysroot,
	"-arch",
	target_cpu,
	"-stdlib=libc++",
	]
	libs += [ "objc" ]

	# We used to link all our iOS tools together, so none actually defines main().
	# Instead they each define their own entry point, which our iOS mega-app called.
	# If we can we'd like to not do that anymore. While we're building both ways, here's
	# our clever hack to give each tool back its own main().
	cflags += [
	"-Ddm_main=main",
	"-Dnanobench_main=main",
	"-Dtool_main=main",
	"-Dtest_main=main",
	]
	}

	if (is_linux) {
	libs += [ "pthread" ]
	}

	if (sanitize != "") {
	# You can either pass the sanitizers directly, e.g. "address,undefined",
	# or pass one of the couple common aliases used by the bots.
	sanitizers = sanitize
	if (sanitize == "ASAN") {
	sanitizers = "address,bool,function,integer-divide-by-zero,nonnull-attribute,null,object-size,return,returns-nonnull-attribute,shift,signed-integer-overflow,unreachable,vla-bound,vptr"
	} else if (sanitize == "TSAN") {
	sanitizers = "thread"
	} else if (sanitize == "MSAN") {
	sanitizers = "memory"
	}

	cflags += [
	"-fsanitize=$sanitizers",
	"-fno-sanitize-recover=$sanitizers",
	"-fsanitize-blacklist=" + rebase_path("../tools/xsan.blacklist"),
	]
	ldflags += [ "-fsanitize=$sanitizers" ]
	if (sanitizers == "memory") {
	cflags += [ "-fsanitize-memory-track-origins" ]
	cflags_cc += [ "-stdlib=libc++" ]
	ldflags += [ "-stdlib=libc++" ]
	}
	}
	}

	config("no_exceptions") {
	# Exceptions are disabled by default on Windows. (Use /EHsc to enable them.)
	if (!is_win) {
	cflags_cc = [ "-fno-exceptions" ]
	}
	}

	config("warnings") {
	cflags = []
	cflags_cc = []
	cflags_objc = []
	if (is_win) {
	cflags += [
	"/W3", # Turn on lots of warnings.

	# Disable a bunch of warnings:
	"/wd4244", # conversion from 'float' to 'int', possible loss of data
	"/wd4267", # conversion from 'size_t' to 'int', possible loss of data
	"/wd4800", # forcing value to bool 'true' or 'false' (performance warning)

	# Probably only triggers when /EHsc is enabled.
	"/wd4291", # no matching operator delete found;
	# memory will not be freed if initialization throws an exception
	]
	} else {
	cflags += [
	"-Wall",
	"-Wextra",
	"-Winit-self",
	"-Wpointer-arith",
	"-Wsign-compare",
	"-Wvla",

	"-Wno-deprecated-declarations",
	"-Wno-maybe-uninitialized",
	]
	cflags_cc += [ "-Wnon-virtual-dtor" ]

	if (is_clang) {
	cflags += [
	"-Weverything",
	"-Wno-unknown-warning-option", # Let older Clangs ignore newer Clangs' warnings.
	]

	if (is_android && target_cpu == "x86") {
	# Clang seems to think new/malloc will only be 4-byte aligned on x86 Android.
	# We're pretty sure it's actually 8-byte alignment.
	cflags += [ "-Wno-over-aligned" ]
	}

	cflags += [
	"-Wno-cast-align",
	"-Wno-conditional-uninitialized",
	"-Wno-conversion",
	"-Wno-disabled-macro-expansion",
	"-Wno-documentation",
	"-Wno-documentation-unknown-command",
	"-Wno-double-promotion",
	"-Wno-exit-time-destructors", # TODO: OK outside libskia
	"-Wno-float-conversion",
	"-Wno-float-equal",
	"-Wno-format-nonliteral",
	"-Wno-global-constructors", # TODO: OK outside libskia
	"-Wno-gnu-zero-variadic-macro-arguments",
	"-Wno-missing-prototypes",
	"-Wno-missing-variable-declarations",
	"-Wno-pedantic",
	"-Wno-reserved-id-macro",
	"-Wno-shadow",
	"-Wno-shift-sign-overflow",
	"-Wno-sign-conversion",
	"-Wno-switch-enum",
	"-Wno-undef",
	"-Wno-unreachable-code",
	"-Wno-unreachable-code-break",
	"-Wno-unreachable-code-return",
	"-Wno-unused-macros",
	"-Wno-unused-member-function",
	]
	cflags_cc += [
	"-Wno-abstract-vbase-init",
	"-Wno-weak-vtables",
	]

	# We are unlikely to want to fix these.
	cflags += [
	"-Wno-covered-switch-default",
	"-Wno-deprecated",
	"-Wno-implicit-fallthrough",
	"-Wno-missing-noreturn",
	"-Wno-old-style-cast",
	"-Wno-padded",
	]
	cflags_cc += [
	"-Wno-c++98-compat",
	"-Wno-c++98-compat-pedantic",
	"-Wno-undefined-func-template",
	]
	cflags_objc += [
	"-Wno-direct-ivar-access",
	"-Wno-objc-interface-ivars",
	]
	}
	}
	}
	config("warnings_except_public_headers") {
	if (!is_win) {
	cflags = [ "-Wno-unused-parameter" ]
	}
	}

	config("extra_flags") {
	cflags = extra_cflags
	cflags_c = extra_cflags_c
	cflags_cc = extra_cflags_cc
	ldflags = extra_ldflags
	}

	config("debug_symbols") {
	# It's annoying to wait for full debug symbols to push over
	# to Android devices. -gline-tables-only is a lot slimmer.
	if (is_android) {
	cflags = [ "-gline-tables-only" ]
	} else if (is_win) {
	cflags = [ "/Zi" ]
	ldflags = [ "/DEBUG" ]
	} else {
	cflags = [ "-g" ]
	}
	}

	config("no_rtti") {
	if (sanitize != "ASAN") { # -fsanitize=vptr requires RTTI
	if (is_win) {
	cflags_cc = [ "/GR-" ]
	} else {
	cflags_cc = [ "-fno-rtti" ]
	}
	}
	}

	config("release") {
	if (is_win) {
	cflags = [
	"/O2",
	"/Zc:inline",
	"/GS-",
	]
	ldflags = [
	"/OPT:ICF",
	"/OPT:REF",
	]
	} else {
	cflags = [
	"-O3",
	"-momit-leaf-frame-pointer",
	]
	}
	defines = [ "NDEBUG" ]
	}

	config("executable") {
	if (is_android) {
	ldflags = [ "-pie" ]
	} else if (is_mac) {
	ldflags = [ "-Wl,-rpath,@loader_path/." ]
	} else if (is_linux) {
	ldflags = [
	"-rdynamic",
	"-Wl,-rpath,\$ORIGIN",
	]
	} else if (is_win) {
	ldflags = [
	"/SUBSYSTEM:CONSOLE", # Quiet "no subsystem specified; CONSOLE assumed".
	"/INCREMENTAL:NO", # Quiet warnings about failing to incrementally link by never trying to.
	]
	}
	}

	toolchain("msvc") {
	lib_dir_switch = "/LIBPATH:"

	bin = "$windk/VC/bin/amd64"
	env_setup = ""
	if (target_cpu == "x86") {
	bin += "_x86"
	env_setup = "cmd /c $windk/win_sdk/bin/SetEnv.cmd /x86 && "
	}

	tool("cc") {
	rspfile = "{{output}}.rsp"
	precompiled_header_type = "msvc"
	pdbname = "{{target_out_dir}}/{{label_name}}_c.pdb"

	# Label names may have spaces so pdbname must be quoted.
	command = "$env_setup$bin/cl.exe /nologo /showIncludes /FC @$rspfile /c {{source}} /Fo{{output}} /Fd\"$pdbname\""
	depsformat = "msvc"
	outputs = [
	"{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.obj",
	]
	rspfile_content = "{{defines}} {{include_dirs}} {{cflags}} {{cflags_c}}"
	description = "compile {{source}}"
	}

	tool("cxx") {
	rspfile = "{{output}}.rsp"
	precompiled_header_type = "msvc"
	pdbname = "{{target_out_dir}}/{{label_name}}_c.pdb"

	# Label names may have spaces so pdbname must be quoted.
	command = "$env_setup$bin/cl.exe /nologo /showIncludes /FC @$rspfile /c {{source}} /Fo{{output}} /Fd\"$pdbname\""
	depsformat = "msvc"
	outputs = [
	"{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.obj",
	]
	rspfile_content = "{{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}}"
	description = "compile {{source}}"
	}

	tool("alink") {
	rspfile = "{{output}}.rsp"

	command = "$env_setup$bin/lib.exe /nologo /ignore:4221 {{arflags}} /OUT:{{output}} @$rspfile"
	outputs = [
	# Ignore {{output_extension}} and always use .lib, there's no reason to
	# allow targets to override this extension on Windows.
	"{{root_out_dir}}/{{target_output_name}}{{output_extension}}",
	]
	default_output_extension = ".lib"
	default_output_dir = "{{target_out_dir}}"

	# inputs_newline works around a fixed per-line buffer size in the linker.
	rspfile_content = "{{inputs_newline}}"
	description = "link {{output}}"
	}

	tool("solink") {
	dllname = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
	libname = "${dllname}.lib"
	pdbname = "${dllname}.pdb"
	rspfile = "${dllname}.rsp"

	command = "$env_setup$bin/link.exe /nologo /IMPLIB:$libname /DLL /OUT:$dllname /PDB:$pdbname @$rspfile"
	outputs = [
	dllname,
	libname,
	pdbname,
	]
	default_output_extension = ".dll"
	default_output_dir = "{{root_out_dir}}"

	link_output = libname
	depend_output = libname
	runtime_outputs = [
	dllname,
	pdbname,
	]

	# I don't quite understand this. Aping Chrome's toolchain/win/BUILD.gn.
	restat = true

	# inputs_newline works around a fixed per-line buffer size in the linker.
	rspfile_content = "{{inputs_newline}} {{libs}} {{solibs}} {{ldflags}}"
	description = "link {{output}}"
	}

	tool("link") {
	exename = "{{root_out_dir}}/{{target_output_name}}{{output_extension}}"
	pdbname = "$exename.pdb"
	rspfile = "$exename.rsp"

	command =
	"$env_setup$bin/link.exe /nologo /OUT:$exename /PDB:$pdbname @$rspfile"

	default_output_extension = ".exe"
	default_output_dir = "{{root_out_dir}}"
	outputs = [
	exename,
	]

	# inputs_newline works around a fixed per-line buffer size in the linker.
	rspfile_content = "{{inputs_newline}} {{libs}} {{solibs}} {{ldflags}}"
	description = "link {{output}}"
	}

	tool("stamp") {
	command = "$stamp {{output}}"
	description = "stamp {{output}}"
	}

	tool("copy") {
	cp_py = rebase_path("cp.py")
	command = "$python $cp_py {{source}} {{output}}"
	description = "copy {{source}} {{output}}"
	}
	}

	toolchain("gcc_like") {
	lib_switch = "-l"
	lib_dir_switch = "-L"

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

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

	tool("objc") {
	depfile = "{{output}}.d"
	command = "$cc_wrapper $cc -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_objc}} -c {{source}} -o {{output}}"
	depsformat = "gcc"
	outputs = [
	"{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
	]
	description = "compile {{source}}"
	}

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

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

	tool("alink") {
	rspfile = "{{output}}.rsp"
	rspfile_content = "{{inputs}}"
	ar_py = rebase_path("ar.py")
	command = "$python $ar_py $ar {{output}} $rspfile"
	outputs = [
	"{{root_out_dir}}/{{target_output_name}}{{output_extension}}",
	]
	default_output_extension = ".a"
	output_prefix = "lib"
	description = "link {{output}}"
	}

	tool("solink") {
	soname = "{{target_output_name}}{{output_extension}}"

	rpath = "-Wl,-soname,$soname"
	if (is_mac) {
	rpath = "-Wl,-install_name,@rpath/$soname"
	}

	command = "$cc_wrapper $cxx -shared {{ldflags}} {{inputs}} {{solibs}} {{libs}} $rpath -o {{output}}"
	outputs = [
	"{{root_out_dir}}/$soname",
	]
	output_prefix = "lib"
	default_output_extension = ".so"
	description = "link {{output}}"
	}

	tool("link") {
	command = "$cc_wrapper $cxx {{ldflags}} {{inputs}} {{solibs}} {{libs}} -o {{output}}"
	outputs = [
	"{{root_out_dir}}/{{target_output_name}}{{output_extension}}",
	]
	description = "link {{output}}"
	}

	tool("stamp") {
	command = "$stamp {{output}}"
	description = "stamp {{output}}"
	}

	tool("copy") {
	cp_py = rebase_path("cp.py")
	command = "$python $cp_py {{source}} {{output}}"
	description = "copy {{source}} {{output}}"
	}
	}