swiftc : Possible values for "-target" command line option

Question

Swift 编译器选项 -target:

$ swiftc -h
...

 -target <value>         Generate code for the given target
...

从哪里可以获得编译器选项 -target 的所有可能值(即:x86_64-apple-ios11.0、x86_64-apple-macosx10. 12, ...) ?

谢谢!

Answer 1

看https://github.com/apple/swift/blob/master/utils/build-script-impl

在构建脚本中搜索 SWIFT_HOST_VARIANT、SWIFT_HOST_VARIANT_SDK、SWIFT_HOST_VARIANT_ARCH 和 SWIFT_HOST_TRIPLE 等术语

#!/usr/bin/env bash
#===--- build-script-impl - Implementation details of build-script ---------===#
#
## This source file is part of the Swift.org open source project
# Each variable name is re-exported into this script in uppercase, where dashes
# are substituted by underscores. For example, `swift-install-components` is
# referred to as `SWIFT_INSTALL_COMPONENTS` in the remainder of this script.

KNOWN_SETTINGS=(
  # name            default      description
  # ... snip ...
  darwin-deployment-version-osx   "10.9"   "minimum deployment target version for OS X"
  darwin-deployment-version-ios   "7.0"    "minimum deployment target version for iOS"
  # ... snip ...
function set_build_options_for_host() {
  llvm_cmake_options=()
  swift_cmake_options=()
  cmark_cmake_options=()
  lldb_cmake_options=()
  swiftpm_bootstrap_options=()
  SWIFT_HOST_VARIANT=
  SWIFT_HOST_VARIANT_SDK=
  SWIFT_HOST_VARIANT_ARCH=
  SWIFT_HOST_TRIPLE=
  local host="$1"

  # Hosts which can be cross-compiled must specify:
  # SWIFT_HOST_TRIPLE and llvm_target_arch (as well as usual HOST_VARIANT flags)
  case ${host} in
    freebsd-x86_64)
      SWIFT_HOST_VARIANT="freebsd"
      SWIFT_HOST_VARIANT_SDK="FREEBSD"
      SWIFT_HOST_VARIANT_ARCH="x86_64"
      ;;
    cygwin-x86_64)
      SWIFT_HOST_VARIANT="cygwin"
      SWIFT_HOST_VARIANT_SDK="CYGWIN"
      SWIFT_HOST_VARIANT_ARCH="x86_64"
      ;;
# ... snip ...
    linux-*)
      SWIFT_HOST_VARIANT="linux"
      SWIFT_HOST_VARIANT_SDK="LINUX"
      case ${host} in
        linux-x86_64)
          SWIFT_HOST_VARIANT_ARCH="x86_64"
          ;;
# ... snip ...
        linux-aarch64)
          SWIFT_HOST_VARIANT_ARCH="aarch64"
          ;;
# ... snip ...
    ;;
    macosx-* | iphoneos-* | iphonesimulator-* | \
      appletvos-* | appletvsimulator-* | \
      watchos-* | watchsimulator-*)
      case ${host} in
        macosx-x86_64)
          xcrun_sdk_name="macosx"
          llvm_target_arch=""
          SWIFT_HOST_TRIPLE="x86_64-apple-macosx${DARWIN_DEPLOYMENT_VERSION_OSX}"
          SWIFT_HOST_VARIANT="macosx"
          SWIFT_HOST_VARIANT_SDK="OSX"
          SWIFT_HOST_VARIANT_ARCH="x86_64"