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rust/compiler/rustc_target
Guillaume Gomez fe49981ea0
Rollup merge of #94703 - kjetilkjeka:nvptx-kernel-args-abi2, r=nagisa
Fix codegen bug in "ptx-kernel" abi related to arg passing

I found a codegen bug in the nvptx abi related to that args are passed as ptrs ([see comment](https://github.com/rust-lang/rust/issues/38788#issuecomment-1048999928)), this is not as specified in the [ptx-interoperability doc](https://docs.nvidia.com/cuda/ptx-writers-guide-to-interoperability/) or how C/C++ does it. It will also almost always fail in practice since device/host uses different memory spaces for most hardware.

This PR fixes the bug and add tests for passing structs to ptx kernels.

I observed that all nvptx assembly tests had been marked as [ignore a long time ago](https://github.com/rust-lang/rust/pull/59752#issuecomment-501713428). I'm not sure if the new one should be marked as ignore, it passed on my computer but it might fail if ptx-linker is missing on the server? I guess this is outside scope for this PR and should be looked at in a different issue/PR.

I only fixed the nvptx64-nvidia-cuda target and not the potential code paths for the non-existing 32bit target. Even though 32bit nvptx is not a supported target there are still some code under the hood supporting codegen for 32 bit ptx. I was advised to create an MCP to find out if this code should be removed or updated.

Perhaps ``@RDambrosio016`` would have interest in taking a quick look at this.
2022-04-26 13:22:27 +02:00
..
src Rollup merge of #94703 - kjetilkjeka:nvptx-kernel-args-abi2, r=nagisa 2022-04-26 13:22:27 +02:00
Cargo.toml Migrate to 2021 2021-09-20 22:21:42 -04:00
README.md Fix outdated crate names in compiler docs 2021-04-08 11:12:14 -05:00

rustc_target contains some very low-level details that are specific to different compilation targets and so forth.

For more information about how rustc works, see the rustc dev guide.