带有 ARM 的 Mac M1 pro 机器中的 Mediapipe，在为 hello_world 构建 bazel 时面临 AUTORELEASEPOOL 问题

Question

I am using the latest Mac M1 pro (ARM) machine and was trying to install mediapipe as per this tutorial - https://google.github.io/mediapipe/getting_started/install.html#installing-on-macos .

I was consistently getting the following error during this command:

$ bazel run --define MEDIAPIPE_DISABLE_GPU=1 \
    mediapipe/examples/desktop/hello_world:hello_world

Error :

mediapipe/framework/scheduler_queue.cc:212:3: error: expected expression
  AUTORELEASEPOOL {
  ^
mediapipe/framework/scheduler_queue.cc:29:25: note: expanded from macro 'AUTORELEASEPOOL'

Answer 1

While looking into the error carefully and tracing back to the mediapipe framework file scheduler_queue.cc I found there is some issue in AUTORELEASEPOOL define.

I've updated this line ''' #define AUTORELEASEPOOL @autoreleasepool ''' to ''' #define AUTORELEASEPOOL '''

and it works for me, as I'm able to build mediapipe hello_world as expected.

Seems like, scheduler_queue.cc has not been written carefully considering this type of issues or maybe needs to be tested more.

Hopefully, this will help you all.

Thanks

Answer 2

It looks like M1 Mac is not detected properly by Bazel as an apple build and a change in mediapipe/framework/BUILD needs to be done

cc_library(
    name = "scheduler_queue",
    srcs = ["scheduler_queue.cc"],
    hdrs = [
        "scheduler_queue.h",
        "scheduler_shared.h",
    ],
    copts = select({
    -        "//conditions:default": [],
    +        "//conditions:default": ["-ObjC++"],
        "//mediapipe:apple": [
            "-ObjC++",
        ],
    }),

This will allow Objective C++ directive @autoreleasepool to be available which is used here for memory management. It is not a good idea to get rid of it in code (as in the answer from hemant kshirsagar).