33add367e2
The `gpu-kernel` calling convention has several restrictions that were not enforced by the compiler until now. Add the following restrictions: 1. Cannot be async 2. Cannot be called 3. Cannot return values, return type must be `()` or `!` 4. Arguments should be primitives, i.e. passed by value. More complicated types can work when you know what you are doing, but it is rather unintuitive, one needs to know ABI/compiler internals. 5. Export name should be unmangled, either through `no_mangle` or `export_name`. Kernels are searched by name on the CPU side, having a mangled name makes it hard to find and probably almost always unintentional.
86 lines
3.2 KiB
Text
86 lines
3.2 KiB
Text
warning: `extern` fn uses type `()`, which is not FFI-safe
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--> $DIR/lint-gpu-kernel.rs:36:35
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LL | extern "gpu-kernel" fn arg_zst(_: ()) { }
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| ^^ not FFI-safe
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= help: consider using a struct instead
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= note: tuples have unspecified layout
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= note: `#[warn(improper_ctypes_definitions)]` on by default
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warning: passing type `()` to a function with "gpu-kernel" ABI may have unexpected behavior
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--> $DIR/lint-gpu-kernel.rs:36:35
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LL | extern "gpu-kernel" fn arg_zst(_: ()) { }
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| ^^
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= help: use primitive types and raw pointers to get reliable behavior
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= note: `#[warn(improper_gpu_kernel_arg)]` on by default
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warning: passing type `&i32` to a function with "gpu-kernel" ABI may have unexpected behavior
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--> $DIR/lint-gpu-kernel.rs:41:35
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LL | extern "gpu-kernel" fn arg_ref(_: &i32) { }
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| ^^^^
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= help: use primitive types and raw pointers to get reliable behavior
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warning: passing type `&mut i32` to a function with "gpu-kernel" ABI may have unexpected behavior
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--> $DIR/lint-gpu-kernel.rs:44:39
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LL | extern "gpu-kernel" fn arg_ref_mut(_: &mut i32) { }
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| ^^^^^^^^
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= help: use primitive types and raw pointers to get reliable behavior
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warning: `extern` fn uses type `S`, which is not FFI-safe
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--> $DIR/lint-gpu-kernel.rs:49:38
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LL | extern "gpu-kernel" fn arg_struct(_: S) { }
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| ^ not FFI-safe
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= help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
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= note: this struct has unspecified layout
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note: the type is defined here
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--> $DIR/lint-gpu-kernel.rs:47:1
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LL | struct S { a: i32, b: i32 }
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| ^^^^^^^^
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warning: passing type `S` to a function with "gpu-kernel" ABI may have unexpected behavior
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--> $DIR/lint-gpu-kernel.rs:49:38
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LL | extern "gpu-kernel" fn arg_struct(_: S) { }
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| ^
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= help: use primitive types and raw pointers to get reliable behavior
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warning: `extern` fn uses type `(i32, i32)`, which is not FFI-safe
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--> $DIR/lint-gpu-kernel.rs:54:35
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LL | extern "gpu-kernel" fn arg_tup(_: (i32, i32)) { }
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| ^^^^^^^^^^ not FFI-safe
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= help: consider using a struct instead
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= note: tuples have unspecified layout
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warning: passing type `(i32, i32)` to a function with "gpu-kernel" ABI may have unexpected behavior
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--> $DIR/lint-gpu-kernel.rs:54:35
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LL | extern "gpu-kernel" fn arg_tup(_: (i32, i32)) { }
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| ^^^^^^^^^^
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= help: use primitive types and raw pointers to get reliable behavior
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warning: function with the "gpu-kernel" ABI has a mangled name
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--> $DIR/lint-gpu-kernel.rs:61:1
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LL | pub extern "gpu-kernel" fn mangled_kernel() { }
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: use `unsafe(no_mangle)` or `unsafe(export_name = "<name>")`
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= note: mangled names make it hard to find the kernel, this is usually not intended
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= note: `#[warn(missing_gpu_kernel_export_name)]` on by default
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warning: 9 warnings emitted
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