使用Bazel编译go-webp时libwebp出现arm64符号缺失问题排查咨询

问题背景 #

尝试用Bazel编译go-webp包，需从源码编译libwebp依赖，但在arm64架构的macOS上构建时，链接器提示缺失_SharpYuvConvert、_SharpYuvGetConversionMatrix、_SharpYuvInit符号。

当前配置 #

WORKSPACE中libwebp源码拉取配置 #

git_repository(
    name = "libwebp",
    remote = "https://chromium.googlesource.com/webm/libwebp",
    commit = "9ce982fdf21764ef7b273f91d6d72721656c3e03",
    build_file = "//:bazel/libwebp/BUILD.bazel",
)

//:bazel/libwebp/BUILD.bazel #

filegroup(
    name = "srcs",
    srcs = glob(
        ["**/*"],
        exclude = ["bazel*/**"],
    ),
    visibility = ["//visibility:public"],
)

//:external/libwebp/BUILD.bazel编译配置 #

load("@rules_foreign_cc//foreign_cc:defs.bzl", "configure_make")

configure_make(
    name = "libwebp",
    autogen = True,
    configure_in_place = True,
    configure_options = [],
    env = select({
        "@platforms//os:macos": {
            "AR": "/usr/bin/ar",
        },
        "//conditions:default": {},
    }),
    lib_source = "@libwebp//:srcs",
    visibility = ["//visibility:public"],
)

go-webp仓库配置 #

go_repository(
    name = "com_github_kolesa_team_go_webp",
    importpath = "github.com/kolesa-team/go-webp",
    patches = ["//:bazel/com_github_kolesa_team_go_webp/build.patch"],  # keep
    sum = "h1:wQvU4PLG/X7RS0vAeyhiivhLRoxfLVRlDq4I3frdxIQ=",
    version = "v1.0.4",
)

补丁内容 #

--- encoder/BUILD.bazel
+++ encoder/BUILD.bazel
@@ -7,7 +7,7 @@
         "options.go",
     ],
     cgo = True,
-    clinkopts = ["-lwebp"],
+    cdeps = ["@asset-tracker//external/libwebp"],
     importpath = "github.com/kolesa-team/go-webp/encoder",
     visibility = ["//visibility:public"],
 )

错误信息 #

ld: warning: ignoring duplicate libraries: '-lc++', '-lm'
Undefined symbols for architecture arm64:
  "_SharpYuvConvert", referenced from:
      _PreprocessARGB in libwebp.a[87](libwebpencode_la-picture_csp_enc.o)
  "_SharpYuvGetConversionMatrix", referenced from:
      _PreprocessARGB in libwebp.a[87](libwebpencode_la-picture_csp_enc.o)
  "_SharpYuvInit", referenced from:
      _ImportYUVAFromRGBA in libwebp.a[87](libwebpencode_la-picture_csp_enc.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

link: error running subcommand external/go_sdk/pkg/tool/darwin_arm64/link: exit status 2

系统信息 #

Darwin 23.5.0 Darwin Kernel Version 23.5.0: Wed May  1 20:14:38 PDT 2024; root:xnu-10063.121.3~5/RELEASE_ARM64_T6020 arm64
bazel 7.2.1

调试步骤与解决方案 #

• 启用libwebp的SharpYuv模块：SharpYuv是libwebp的可选组件，默认未启用。修改configure_make的configure_options添加启用参数：

  configure_options = [
      "--enable-sharpyuv",
  ],
  

  重新编译后，用以下命令验证符号是否存在：

  nm -arch arm64 bazel-bin/external/libwebp/libwebp.a | grep SharpYuv
  

• 明确指定编译架构：macOS arm64下，需避免架构匹配错误，在configure_options中添加架构参数：

  configure_options = [
      "--enable-sharpyuv",
      "--host=aarch64-apple-darwin",
  ],
  

• 修正补丁中的依赖路径：补丁中@asset-tracker//external/libwebp可能与实际工作空间路径不匹配，改为对应libwebp编译目标的正确路径，比如@libwebp//:libwebp。

• 查看编译日志定位问题：添加--subcommands参数运行Bazel，查看configure和make的具体执行命令，确认SharpYuv模块是否被正确编译：

  bazel build //your/target --subcommands
  

• 手动编译验证：拉取指定commit的libwebp源码，执行以下命令手动编译，验证符号是否存在：

  ./autogen.sh && ./configure --enable-sharpyuv && make
  nm -arch arm64 libwebp.a | grep SharpYuv
  

  若手动编译正常，说明Bazel的configure_make配置存在遗漏。

• 检查静态库架构兼容性：用以下命令确认生成的libwebp.a是arm64架构：

  lipo -info bazel-bin/external/libwebp/libwebp.a
  

内容的提问来源于stack exchange，提问作者Victor