spirv-val fails for a module using derived Eq::eq to the target spirv-unknown-vulkan1.2

[hatoo]

Expected Behaviour

#![cfg_attr(
    target_arch = "spirv",
    no_std,
    feature(register_attr),
    register_attr(spirv)
)]

#[cfg(not(target_arch = "spirv"))]
use spirv_std::macros::spirv;

use spirv_std as _;

#[derive(PartialEq, Eq)]
struct T(u32);

#[spirv(fragment)]
pub fn main(out: &mut f32) {
    if T(0) == T(0) {
        *out = 1.0;
    }
}

will succeed to compile and pass spirv-val to "spirv-unknown-vulkan1.2".
It's Ok if the target is "spirv-unknown-spv1.3".

Example & Steps To Reproduce

1. clone https://github.com/hatoo/rust-gpu-issue/tree/error-vulkan-12 (note: error-vulkan-12 branch)
2. cargo build
3. errors

> cargo build
   Compiling builder v0.1.0 (C:\Users\hato2\Desktop\rust-gpu-issue\builder)
error: failed to run custom build command for `builder v0.1.0 (C:\Users\hato2\Desktop\rust-gpu-issue\builder)`

Caused by:
  process didn't exit successfully: `C:\Users\hato2\Desktop\rust-gpu-issue\target\debug\build\builder-a70f151e87e6f8ef\build-script-build` (exit code: 1)
  --- stderr
     Compiling shader v0.1.0 (C:\Users\hato2\Desktop\rust-gpu-issue\shader)
  error: Interface variable id <12> is used by entry point 'main' id <1>, but is not listed as an interface
    %12 = OpVariable %_ptr_Private_uint Private %uint_0

    |
    = note: module `C:\Users\hato2\Desktop\rust-gpu-issue\target\spirv-builder\spirv-unknown-vulkan1.2\release\deps\shader.spv.dir\module`

  warning: an unknown error occurred
    |
    = note: spirv-opt failed, leaving as unoptimized
    = note: module `C:\Users\hato2\Desktop\rust-gpu-issue\target\spirv-builder\spirv-unknown-vulkan1.2\release\deps\shader.spv.dir\module`

  error: error:0:0 - Interface variable id <12> is used by entry point 'main' id <1>, but is not listed as an interface
    %12 = OpVariable %_ptr_Private_uint Private %uint_0

    |
    = note: spirv-val failed
    = note: module `C:\Users\hato2\Desktop\rust-gpu-issue\target\spirv-builder\spirv-unknown-vulkan1.2\release\deps\shader.spv.dir\module`

  warning: `shader` (lib) generated 1 warning
  error: could not compile `shader` due to 2 previous errors; 1 warning emitted
  Error: BuildFailed

It's Ok if the target is "spirv-unknown-spv1.3".

System Info

• Rust: 1.56.0-nightly (ae90dcf02 2021-08-09)
• OS: Windows 11 Pro
• GPU: RTX 2080ti
• SPIR-V: v2021.2-dev v2021.1-42-g5dd2f769

Backtrace

Backtrace

<backtrace>

[msiglreith]

fwiw I wrote some linker pass to collect the necessary variables for the entrypoint supporting spv1.4+, right now only Input/Output storage class variables are listed in entrypoints. entrypoint parameters are added
msiglreith@668e40b

edit: thanks to khyperia for correction

[khyperia]

right now only Input/Output storage class variables are listed in entrypoints.

This isn't correct - to clarify, we support adding all relevant variables in the entrypoint function to the interface list for versions >= 1.4. That code is here.

The issue is specifically with constants that contain pointers to other constants, which are generated as Private variables here. The issue here is that there is a reference taken to a constant, &T(0) (Eq takes its arguments by reference), and that constant needs to be added to the interface list, even though it's not part of any interface.

[eddyb]

There's a quick repro in-tree FWIW:

cargo compiletest --target-env vulkan1.2

failures:
    [ui] ui/arch/debug_printf.rs
    [ui] ui/arch/ray_query_initialize_khr.rs
    [ui] ui/dis/asm_op_decorate.rs
    [ui] ui/dis/complex_image_sample_inst.rs
    [ui] ui/image/sample_depth_reference/sample_lod.rs
    [ui] ui/lang/consts/nested-ref.rs
    [ui] ui/lang/consts/shallow-ref.rs
    [ui] ui/lang/core/ops/range-contains.rs

test result: FAILED. 164 passed; 8 failed; 0 ignored; 0 measured; 0 filtered out; finished in 8.61s

6 out of those 8 failures are this error, so it's generally getting in the way of vulkan1.2 support at this moment (the other 2 are unrelated minor oversights in the tests, where newer Vulkan forces better validation AFAICT).