gn/BUILD.gn

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

if (is_fuchsia) {
  import("//build/fuchsia/sdk.gni")
}

declare_args() {
  extra_asmflags = []
  extra_cflags = []
  extra_cflags_c = []
  extra_cflags_cc = []
  extra_ldflags = []

  malloc = ""
  werror = false
  xcode_sysroot = ""
}

if (is_ios && xcode_sysroot == "") {
  if (is_tvos) {
    sdk = "appletvos"
    if (target_cpu == "x86" || target_cpu == "x64") {
      sdk = "appletvsimulator"
    }
  } else {
    sdk = "iphoneos"
    if (target_cpu == "x86" || target_cpu == "x64") {
      sdk = "iphonesimulator"
    }
  }
  xcode_sysroot = exec_script("find_xcode_sysroot.py", [ sdk ], "trim string")
}

# If building for mac on a mac then lookup all the system includes so that goma and the clang
# shipped with chrome can find them. When the gn_to_bp.py tool is run, then the host_os != mac.
# In this case leave the xcode_sysroot empty, and the cc/c++ that come with XCode will be able to
# find needed include paths.
if (is_mac && host_os == "mac" && xcode_sysroot == "") {
  xcode_sysroot =
      exec_script("find_xcode_sysroot.py", [ "macosx" ], "trim string")
}

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

  if (werror) {
    if (is_win) {
      cflags += [ "/WX" ]
    } else {
      cflags += [ "-Werror" ]
    }
  }

  # Disable warnings about unknown attributes.
  # (These unknown attribute warnings are on by default, so we don't make
  # disabling them part of :warnings, as some targets remove :warnings.)
  if (is_win && !is_clang) {
    cflags += [ "/wd5030" ]
  } else {
    cflags += [ "-Wno-attributes" ]
  }

  if (is_fuchsia && using_fuchsia_sdk) {
    ldflags += [
      "-v",
      "--sysroot=" + rebase_path("$fuchsia_sdk_path/arch/$target_cpu/sysroot"),
    ]
    cflags += [ "--sysroot=" +
                rebase_path("$fuchsia_sdk_path/arch/$target_cpu/sysroot") ]
    if (target_cpu == "x64") {
      target_triple = "--target=x86_64-${target_os}"
    } else if (target_cpu == "arm64") {
      target_triple = "--target=aarch64-unknown-${target_os}"
    } else {
      print("Unknown target CPU for Fuchsia target build.")
      assert(false)
    }
    ldflags += [ target_triple ]
    cflags += [ target_triple ]
    asmflags += [ target_triple ]
  }

  if (is_win) {
    if (is_clang && target_cpu == "arm64") {
      cflags += [ "--target=arm64-windows" ]
    }
    cflags += [
      "/bigobj",  # Some of our files are bigger than the regular limits.
      "/utf-8",  # Set Source and Executable character sets to UTF-8.
    ]
    cflags_cc += [ "/std:c++17" ]
    defines += [
      "_CRT_SECURE_NO_WARNINGS",  # Disables warnings about sscanf().
      "_HAS_EXCEPTIONS=0",  # Disables exceptions in MSVC STL.
      "WIN32_LEAN_AND_MEAN",
      "NOMINMAX",
    ]

    _include_dirs = [
      "$win_vc/Tools/MSVC/$win_toolchain_version/include",
      "$win_sdk/Include/$win_sdk_version/shared",
      "$win_sdk/Include/$win_sdk_version/ucrt",
      "$win_sdk/Include/$win_sdk_version/um",
      "$win_sdk/Include/$win_sdk_version/winrt",
    ]

    if (is_clang) {
      foreach(dir, _include_dirs) {
        cflags += [
          "-imsvc",
          dir,
        ]
      }
    } else {
      include_dirs = _include_dirs
    }

    lib_dirs = [
      "$win_sdk/Lib/$win_sdk_version/ucrt/$target_cpu",
      "$win_sdk/Lib/$win_sdk_version/um/$target_cpu",
      "$win_vc/Tools/MSVC/$win_toolchain_version/lib/$target_cpu",
    ]
  } else {
    cflags += [
      "-fstrict-aliasing",
      "-fPIC",
      "-fvisibility=hidden",
    ]
    cflags_cc += [
      "-std=c++17",
      "-fvisibility-inlines-hidden",
    ]
  }

  if (current_cpu == "arm") {
    cflags += [
      "-march=armv7-a",
      "-mfpu=neon",
      "-mthumb",
    ]
  } 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) {
    cflags += [ "--sysroot=$ndk/toolchains/llvm/prebuilt/$ndk_host/sysroot" ]
    ldflags += [ "-static-libstdc++" ]
  }

  if (is_ios) {
    if (target_cpu == "arm") {
      _arch_flags = [
        "-arch",
        "armv7",
      ]
    } else if (target_cpu == "arm64") {
      _arch_flags = [
        "-arch",
        "arm64",
        "-arch",
        "arm64e",
      ]
    } else if (target_cpu == "x86") {
      _arch_flags = [
        "-arch",
        "i386",
      ]
    } else if (target_cpu == "x64") {
      _arch_flags = [
        "-arch",
        "x86_64",
      ]
    } else {
      _arch_flags = [
        "-arch",
        target_cpu,
      ]
    }

    asmflags += [
                  "-isysroot",
                  xcode_sysroot,
                ] + _arch_flags
    cflags += [
                "-isysroot",
                xcode_sysroot,
              ] + _arch_flags
    cflags_cc += [
      "-stdlib=libc++",
      "-fno-aligned-allocation",
    ]
    ldflags += [
                 "-isysroot",
                 xcode_sysroot,
                 "-stdlib=libc++",
               ] + _arch_flags
    libs += [ "objc" ]
  }

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

  if (is_mac) {
    # If there was a xcode_sysroot set in args or calculated then use it, else don't set anything
    # because the XCode cc/c++ already know all this stuff.
    if (xcode_sysroot != "") {
      asmflags += [
        "-isysroot",
        xcode_sysroot,
      ]
      cflags += [
        "-isysroot",
        xcode_sysroot,
      ]
      ldflags += [
        "-isysroot",
        xcode_sysroot,
      ]
    }

    # Disable linker warnings.  They're usually just annoyances like,
    #   ld: warning: text-based stub file
    #     /System/Library/Frameworks/foo.framework/foo.tbd and library file
    #     /System/Library/Frameworks/foo.framework/foo are out of sync.
    #     Falling back to library file for linking.
    ldflags += [ "-Wl,-w" ]

    # As of 11/2020, gn is an x86 binary and defaults the host_cpu to x86_64.
    # This allows you to build arm64 mac binaries by setting target_cpu = "arm64"
    if (current_cpu == "arm64") {
      asmflags += [
        "-target",
        "arm64-apple-macos11",
      ]
      cflags += [
        "-target",
        "arm64-apple-macos11",
      ]
      ldflags += [
        "-target",
        "arm64-apple-macos11",
      ]
    }
  }

  if (sanitize != "" && sanitize != "MSVC") {
    # 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") {
      # ASAN implicitly runs all UBSAN checks also.
      sanitizers = "undefined,address"

      if (is_android) {
        # TODO(mtklein): work out UBSAN link errors
        sanitizers = "address"
      }
    } else if (sanitize == "TSAN") {
      sanitizers = "thread"
    } else if (sanitize == "MSAN") {
      sanitizers = "memory"
    }

    _suppressions = rebase_path("../tools/xsan.supp")

    cflags += [
      "-fsanitize=$sanitizers",
      "-fno-sanitize-recover=$sanitizers",
      "-fsanitize-blacklist=$_suppressions",
    ]

    if (is_win) {
      cflags += [
        "/FI$_suppressions",

        # On Release builds, we get strange warnings about string literals.
        "/GF-",
      ]

      assert(clang_win != "")
      libs += [ "$clang_win/lib/clang/$clang_win_version/lib/windows/clang_rt.asan-x86_64.lib" ]
    } else {
      cflags += [
        "-include$_suppressions",
        "-fno-omit-frame-pointer",
      ]

      ldflags += [ "-fsanitize=$sanitizers" ]
    }

    if (is_linux) {
      cflags_cc += [ "-stdlib=libc++" ]
      ldflags += [ "-stdlib=libc++" ]
    }

    if (sanitizers == "memory") {
      cflags += [ "-fsanitize-memory-track-origins" ]
    }
    if (sanitizers == "safe-stack") {
      cflags_cc += [ "-fno-aligned-allocation" ]
    }
  }
}

# See skia:9731.
config("recover_pointer_overflow") {
  cflags = [ "-fsanitize-recover=pointer-overflow" ]
}

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 = []
  cflags_objcc = []
  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

      # These only show up in shared builds:
      "/wd4251",  # class 'type' needs to have dll-interface to be used by
                  # clients of class 'type2'
      "/wd4275",  # non dll-interface class 'base' used as base for
                  # dll-interface class 'derived'

      # It'd be nice to fix these and turn this on:
      "/wd5041",  # out-of-line definition for constexpr static data member is
                  # not needed and is deprecated in C++17

      # warning C4996: 'std::result_of_t': warning STL4014: std::result_of and std::result_of_t are
      # deprecated in C++17. They are superseded by std::invoke_result and std::invoke_result_t.
      "/wd4996",
    ]
  } else {
    cflags += [
      "-Wall",
      "-Wextra",
      "-Winit-self",
      "-Wpointer-arith",
      "-Wsign-compare",
      "-Wvla",

      "-Wno-deprecated-declarations",
      "-Wno-maybe-uninitialized",
      "-Wno-psabi",
    ]
    cflags_cc += [
      "-Wnon-virtual-dtor",
      "-Wno-noexcept-type",
      "-Wno-redundant-move",  #TODO: gcc conflict with return-std-move-in-c++11
    ]
  }

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

    if (target_cpu == "arm" && is_ios) {
      # Clang seems to think new/malloc will only be 4-byte aligned on 32-bit iOS.
      # We're pretty sure it's actually 8-byte alignment.
      cflags += [ "-Wno-over-aligned" ]
    }
    if (target_cpu == "x86" && is_android) {
      # Clang seems to think new/malloc will only be 4-byte aligned on 32-bit x86 Android builds.
      # We're pretty sure it's actually 8-byte alignment.  See OverAlignedTest.cpp for more info.
      cflags += [ "-Wno-over-aligned" ]
    }

    # Shouldn't be necessary for local builds. With distributed Windows builds, files may lose
    # their case during copy, causing case-sensitivity mismatch on remote machines.
    cflags += [
      "-Wno-nonportable-include-path",
      "-Wno-nonportable-system-include-path",
    ]

    # TODO: These would all be really great warnings to turn on.
    cflags += [
      "-Wno-cast-align",
      "-Wno-cast-qual",
      "-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-equal",
      "-Wno-format-nonliteral",
      "-Wno-global-constructors",  # TODO: OK outside libskia
      "-Wno-missing-prototypes",
      "-Wno-missing-variable-declarations",
      "-Wno-pedantic",
      "-Wno-reserved-id-macro",
      "-Wno-shadow",
      "-Wno-shift-sign-overflow",
      "-Wno-signed-enum-bitfield",
      "-Wno-switch-enum",
      "-Wno-undef",
      "-Wno-unreachable-code",
      "-Wno-unreachable-code-break",
      "-Wno-unreachable-code-return",
      "-Wno-unused-macros",
      "-Wno-unused-member-function",
      "-Wno-unused-template",
      "-Wno-zero-as-null-pointer-constant",
      "-Wno-thread-safety-negative",
      "-Wno-non-c-typedef-for-linkage",  # Dawn, not Skia per se.
    ]
    cflags_cc += [
      "-Wno-abstract-vbase-init",
      "-Wno-weak-vtables",
    ]

    # Turn back on after -Wno-conversion.
    # This only affects public headers... see :warnings_except_public_headers.
    cflags += [ "-Wsign-conversion" ]

    # We are unlikely to want to fix these.
    cflags += [
      "-Wno-covered-switch-default",
      "-Wno-deprecated",
      "-Wno-missing-noreturn",
      "-Wno-old-style-cast",
      "-Wno-padded",
      "-Wno-newline-eof",
    ]
    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",
    ]
    cflags_objcc += [
      "-Wno-direct-ivar-access",
      "-Wno-objcc-interface-ivars",
    ]

    # Wno-deprecated turns off the whole group, but also has its own warnings like
    # out-of-line definition of constexpr static data member is redundant in C++17 and is deprecated [-Werror,-Wdeprecated]
    # but we would like others. Created from clang/include/clang/Basic/DiagnosticGroups.td
    cflags += [
      "-Wdeprecated-anon-enum-enum-conversion",
      "-Wdeprecated-array-compare",
      "-Wdeprecated-attributes",
      "-Wdeprecated-comma-subscript",
      "-Wdeprecated-copy",

      #"-Wdeprecated-copy-dtor",
      #"-Wdeprecated-declarations",
      "-Wdeprecated-dynamic-exception-spec",
      "-Wdeprecated-enum-compare",
      "-Wdeprecated-enum-compare-conditional",
      "-Wdeprecated-enum-enum-conversion",
      "-Wdeprecated-enum-float-conversion",
      "-Wdeprecated-increment-bool",
      "-Wdeprecated-register",
      "-Wdeprecated-this-capture",
      "-Wdeprecated-volatile",
      "-Wdeprecated-writable-str",
    ]
  }
}
config("warnings_except_public_headers") {
  if (!is_win || is_clang) {
    cflags = [
      "-Wno-sign-conversion",
      "-Wno-unused-parameter",
    ]
  }
}

config("extra_flags") {
  asmflags = extra_asmflags
  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",
      "-funwind-tables",  # Helps make in-process backtraces fuller.
    ]
  } else if (is_win) {
    cflags = [ "/Z7" ]
    if (is_clang) {
      cflags += [ "-gcodeview-ghash" ]
      ldflags = [ "/DEBUG:GHASH" ]
    } else {
      ldflags = [ "/DEBUG:FASTLINK" ]
    }
  } 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("optimize") {
  if (is_win) {
    cflags = [
      "/O2",
      "/Zc:inline",
    ]
    ldflags = [
      "/OPT:ICF",
      "/OPT:REF",
    ]
  } else {
    cflags = [ "-O3" ]
    if (is_mac || is_ios) {
      ldflags = [ "-dead_strip" ]
    } else {
      cflags += [
        "-fdata-sections",
        "-ffunction-sections",
      ]
      ldflags = [ "-Wl,--gc-sections" ]
    }
    if (target_cpu == "wasm") {
      # The compiler asks us to add an optimization flag to both cflags
      # and ldflags to cut down on the local variables,
      # for performance reasons.
      # The "linking" step is the conversion to javascript.
      ldflags += [ "-O3" ]
    }
  }
}

config("NDEBUG") {
  defines = [ "NDEBUG" ]
}

config("executable") {
  if (is_android) {
    ldflags = [
      "-pie",
      "-rdynamic",
    ]
  } 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.
    ]
  }
}