| # Metal Backend Shaders |
| |
| ANGLE's Metal backend provides a couple of features for inspecting the |
| Metal Shading Language (MSL) produced by ANGLE's shader translator. |
| |
| ## printMetalShaders |
| |
| The [`printMetalShaders` |
| feature](https://chromium-review.googlesource.com/c/angle/angle/+/4480976), |
| which can be enabled in Chromium via the command line argument |
| `--enable-angle-features=printMetalShaders`, dumps the blob cache key |
| and translated MSL for all shaders compiled by ANGLE. This is |
| currently used to [regenerate precompiled |
| shaders](https://crbug.com/1423136) shipped with Chrome. |
| |
| ## Environment variable |
| |
| Setting the environment variable `ANGLE_METAL_PRINT_MSL_ENABLE` to `1` |
| indicates to the Metal backend to print the translated shaders as |
| they're compiled: |
| |
| ``` |
| export ANGLE_METAL_PRINT_MSL_ENABLE=1 |
| /Applications/Google\ Chrome\ Canary.app/Contents/MacOS/Google\ Chrome\ Canary --use-angle=metal |
| ``` |
| |
| To pass this environment to WebKit / Safari's GPU process, set the |
| environment variable `__XPC_ANGLE_METAL_PRINT_MSL_ENABLE` to `1`: |
| |
| ``` |
| export __XPC_ANGLE_METAL_PRINT_MSL_ENABLE=1 |
| /Applications/Safari\ Technology\ Preview.app/Contents/MacOS/Safari\ Technology\ Preview |
| ``` |
