Fuchsia系统ninja编译

使用如下的fx子命令build编译fuchsia代码。实际上运行的是目录tools/devshell/下的编译脚本build。fx将调用ninja运行两次：第一次编译zircon，第二次编译fuchsia。

~/fuchsia$ scripts/fx build

其实，每个fx的子命令都对应着一个tools/devshell目录下的脚本文件：

~/fuchsia$ ls tools/devshell/
add-update-source  cp               lib                 mkzedboot     README.md           serial         shell         wait
aemu               doctor           list-boards         netaddr       reboot              serve          ssh
args               exec             list-packages       netboot       run                 serve-updates  symbolize
build              flash            list-products       netls         run-host-tests      set            syslog           
~/fuchsia$ 

当然，也可以使用fx build命令单独编译zircon。如下编译zircon的default目标：

~/fuchsia$ scripts/fx build zircon/default
ninja: Entering directory `/home/kai/fuchsia/out/default.zircon'
[65/65] STAMP obj/default.stamp
~/fuchsia$ 

或者，单独编译fuchsia的目标target。如下编译fuchsia的default目标，由于依赖于zircon，首先要编译zircon，之后再是编译fuchsia目标。

~/fuchsia$ scripts/fx build default       
ninja: Entering directory `/home/kai/fuchsia/out/default.zircon'
ninja: no work to do.
ninja: Entering directory `/home/kai/fuchsia/out/default'
[1/1] Regenerating ninja files
[355/355] STAMP obj/default.stamp
~/fuchsia$ 

来看一下tools/devshell/build脚本中的主函数main。如果zircon的编译目录不存在，调用fx-gen函数创建（tools/devshell/lib/var.sh），此函数使用buildtools/gn脚本创建编译目录。如上所示，如果指定编译fuchsia的target（如上的default），脚本将自动为zircon_target增加一个default目标。即编译fuchsia时将先编译zircon的default目标。随后调用run-ninja函数进行zircon相关编译，编译目录指定-C为：out/default.zircon。通常情况下参数${zircon_targets[@]}为空。

function main {
  if [ ! -d "$ZIRCON_BUILDROOT" ]; then
    echo >&2 "Re-running gn gen first (missing $ZIRCON_BUILDROOT)"
    fx-gen || return
  fi
  if [ ${#fuchsia_targets[@]} -ne 0 ]; then
    zircon_targets+=(default)
  fi
  run-ninja -C "${ZIRCON_BUILDROOT}" "${switches[@]}" "${zircon_targets[@]}"

在zircon编译完成之后，如果只是编译zircon相关target，主函数至此结束。如果编译zircon的default目标是为了准备编译fuchsia目标，接下来再次调用run-ninja编译fuchsia。编译目录指定为：out/default。

  # If there were explicit Zircon targets and no other explicit targets,
  # the Zircon run was enough by itself.  Otherwise Zircon default is
  # a prerequisite for any Fuchsia target (including implicit default).
  if [ ${#fuchsia_targets[@]} -ne 0 -o ${#zircon_targets[@]} -eq 0 ]; then
    run-ninja -C "${FUCHSIA_BUILD_DIR}" "${switches[@]}" "${fuchsia_targets[@]}"
    fuchsia_status=$?
    if [ "${status}" -eq 0 ]; then
      status="${fuchsia_status}"
    fi
  fi

  return "${status}"
}

简化一下，函数run-ninja仅是封装了fx-run-ninja函数（tools/devshell/lib/vars.sh），最终调用buildtools/ninja脚本执行编译。

function run-ninja {
    (fx-run-ninja "${FUCHSIA_DIR}/buildtools/ninja" "$@") || exit
}

 

脚本buildtools/ninja如下。只是给SCRIPT_ROOT和TOOL_NAME两个变量赋值，调用exec_tool.sh脚本。

readonly SCRIPT_ROOT="$(cd $(dirname ${BASH_SOURCE[0]} ) && pwd)"
readonly TOOL_NAME=$(basename "$0")

source "${SCRIPT_ROOT}/exec_tool.sh"

脚本exec_tool.sh如下。根据系统架构获取动编译工具的路径，执行编译。例如最终的ninja路径为：buildtools/linux-x64/ninja。

case "$(uname -s)" in
  Darwin)
    readonly HOST_PLATFORM="mac-x64"
    ;;
  Linux)
    readonly HOST_PLATFORM="linux-x64"
    ;;
esac

readonly TOOL_PATH="${SCRIPT_ROOT}/${HOST_PLATFORM}/${TOOL_NAME}"

exec "${TOOL_PATH}" "$@"

ninja的编译规则文件默认为build.ninja，如下out/default.zircon目录下的build.ninja文件。

~/fuchsia$ ls -l  out/default.zircon/build.ninja*
-rw-rw-r-- 1 kai kai 1023201 Jun 13 02:46 out/default.zircon/build.ninja
-rw-rw-r-- 1 kai kai   49635 Jun 13 02:46 out/default.zircon/build.ninja.d
~/fuchsia$

使用如下的ninja命令工具deps可查看功能的依赖关系（只显示一部分），目标cowsay.cowsay.o的依赖关系包括一个C文件和多个头文件。

~/fuchsia$ buildtools/linux-x64/ninja -C out/default -t deps
obj/examples/cowsay/cowsay.cowsay.o: #deps 8, deps mtime 1560228190 (VALID)
    ../../examples/cowsay/cowsay.c
    ../../zircon/third_party/ulib/musl/include/stdio.h
    ../../zircon/third_party/ulib/musl/include/features.h
    ../../zircon/third_party/ulib/musl/include/bits/alltypes.h
    ../../zircon/third_party/ulib/musl/include/bits/null.h
    ../../buildtools/linux-x64/clang/lib/clang/9.0.0/include/stddef.h
    ../../zircon/third_party/ulib/musl/include/string.h
    ../../zircon/third_party/ulib/musl/include/strings.h

ninja运行产生的依赖关系和日志文件位于编译目录下，分别为.ninja_deps和.ninja_log。

~/fuchsia$ ls -l out/default/.ninja_*
-rw-rw-r-- 1 kai kai 7086288 Jun 11 06:18 out/default/.ninja_deps
-rw-rw-r-- 1 kai kai 3025583 Jun 13 02:48 out/default/.ninja_log
~/fuchsia$ 

ninja工具命令browse可生成依赖图，启动一个运行在8000端口的web服务，可通过浏览器查看。可指定本地监听地址：--host=192.168.1.x，也可指定监听端口，如--port=8080。

~/fuchsia$ buildtools/linux-x64/ninja -C out/default -t browse
Web server running on localhost:8000, ctl-C to abort...
Web server pid 91479

 

END