1*523fa7a6SAndroid Build Coastguard Worker# buck2 shims 2*523fa7a6SAndroid Build Coastguard Worker 3*523fa7a6SAndroid Build Coastguard WorkerThe `shim/` subtree helps the Meta-internal buck2 build system also work in the 4*523fa7a6SAndroid Build Coastguard Workeropen-source repo. 5*523fa7a6SAndroid Build Coastguard Worker 6*523fa7a6SAndroid Build Coastguard WorkerShims are how open-source buck2 supports a [line 7*523fa7a6SAndroid Build Coastguard Workerlike](https://github.com/pytorch/executorch/blob/50aa517549d10324147534d91d04a923b76421d6/kernels/optimized/targets.bzl#L1): 8*523fa7a6SAndroid Build Coastguard Worker 9*523fa7a6SAndroid Build Coastguard Worker``` 10*523fa7a6SAndroid Build Coastguard Workerload("@fbsource//xplat/executorch/build:runtime_wrapper.bzl", "runtime") 11*523fa7a6SAndroid Build Coastguard Worker``` 12*523fa7a6SAndroid Build Coastguard Worker 13*523fa7a6SAndroid Build Coastguard WorkerIn the open-source repo, `fbsource//xplat` (a Meta-internal root) doesn't exist. 14*523fa7a6SAndroid Build Coastguard WorkerThe `shim = shim` line in `../.buckconfig` tells buck2 to look in 15*523fa7a6SAndroid Build Coastguard Worker[`shim/xplat/executorch/build/runtime_wrapper.bzl`](https://github.com/pytorch/executorch/blob/main/shim/xplat/executorch/build/runtime_wrapper.bzl) 16*523fa7a6SAndroid Build Coastguard Workerinstead. 17