Bazel中是否宣传链接器标志（linkopts）？

Question

I'm building an Android library based on Tensorflow with Bazel.

Here the BUILD file

cc_binary(
    name = "libfoo.so",
    srcs = glob([
         "jni/**/*.cc",
         "jni/**/*.h",
    ]),
    copts = [ "-fexceptions", "-DEIGEN_AVOID_STL_ARRAY",
              "-mfpu=neon", "-std=c++11",
              "-DMIN_LOG_LEVEL=0", "-DTF_LEAN_BINARY",
              "-O2", ],
    linkopts = [
        "-llog",
        "-lm",
    ],
    linkshared = 1,
    deps = [
        "@org_tensorflow//tensorflow/core:android_tensorflow_lib",
        "@boringssl//:crypto",
    ],
)

The linker complains about not finding -lpthread , while I didn't add this flag to linkopts .

I've checked the executed command, and in fact there is extra flags on it: -lz -lpthread ...

Where did they came from ? Is there a workaround for this ?

Answer 1

I got the answer from the tensorflow's issue tracker.

@jart

Since copts and linkopts are viral and propagate to dependencies, -lpthread is most likely being inherited from @boringssl//:crypto

@andrewharp

-lpthread is not necessary or possible on Android, so it sounds like the solution would be to add another condition for the select statement as in the linked commit google/protobuf#1386:

...

The only other workaround I know of that doesn't require editing the other repository is to create a dummy libpthread.so target, but that's pretty hacky.