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Add amdgpu_dispatch_ptr intrinsic There is an ongoing discussion in rust-lang/rust#150452 about using address spaces from the Rust language in some way. As that discussion will likely not conclude soon, this PR adds one rustc_intrinsic with an addrspacecast to unblock getting basic information like launch and workgroup size and make it possible to implement something like `core::gpu`. Add a rustc intrinsic `amdgpu_dispatch_ptr` to access the kernel dispatch packet on amdgpu. The HSA kernel dispatch packet contains important information like the launch size and workgroup size. The Rust intrinsic lowers to the `llvm.amdgcn.dispatch.ptr` LLVM intrinsic, which returns a `ptr addrspace(4)`, plus an addrspacecast to `addrspace(0)`, so it can be returned as a Rust reference. The returned pointer/reference is valid for the whole program lifetime, and is therefore `'static`. The return type of the intrinsic (`&'static ()`) does not mention the struct so that rustc does not need to know the exact struct type. An alternative would be to define the struct as lang item or add a generic argument to the function. Is this ok or is there a better way (also, should it return a pointer instead of a reference)? Short version: ```rust #[cfg(target_arch = "amdgpu")] pub fn amdgpu_dispatch_ptr() -> *const (); ``` Tracking issue: rust-lang/rust#135024 |
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| Cargo.toml | ||
| messages.ftl | ||
| README.md | ||
Please read the rustc-dev-guide chapter on Backend Agnostic Codegen.