Build fails with "Invalid explicit layout decorations on type for operand '355[%_ptr_Function_bubble_buckey_balls__SurfaceData]'"

[ky-bean]

OS: NixOS 25.11 x86_64
Kernel: 6.15.5
DE: KDE Plasma 6.4.2 (Wayland)

I am able to successfully run the project if I change the shader target specified in build.rs to "spirv-unknown-spv1.5", however I'm not sure if that change has implications to other (non-linux especially) systems.

Command: cargo build --features=use-installed-tools --no-default-features
Building with compiled tools results in an error in spirv-tools-sys's C++ code, using installed tools solves that issue for me.

Output:

   Compiling shadertoys-wgpu v0.0.0 (/home/ky/Repos/rust-gpu/rust-gpu-shadertoys)
error: failed to run custom build command for `shadertoys-wgpu v0.0.0 (/home/ky/Repos/rust-gpu/rust-gpu-shadertoys)`

Caused by:
  process didnt exit successfully: `/home/ky/Repos/rust-gpu/rust-gpu-shadertoys/target/debug/build/shadertoys-wgpu-ea89692386d325f8/build-script-build` (exit status: 1)
  --- stdout
  cargo:rerun-if-env-changed=RUSTGPU_CODEGEN_ARGS
  cargo:rerun-if-env-changed=RUSTGPU_RUSTFLAGS
  cargo:rerun-if-env-changed=RUSTGPU_CARGOFLAGS

  --- stderr
     Compiling compiler_builtins v0.1.160 (/home/ky/.rustup/toolchains/nightly-2025-06-23-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/compiler-builtins/compiler-
     Compiling proc-macro2 v1.0.94
     Compiling core v0.0.0 (/home/ky/.rustup/toolchains/nightly-2025-06-23-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core)
     Compiling unicode-ident v1.0.18
     Compiling libm v0.2.11
     Compiling autocfg v1.4.0
     Compiling spirv-std-types v0.9.0 (https://github.com/Rust-GPU/rust-gpu?rev=20052f89d932ee88aba118488fc79393c407e61c#20052f89)
     Compiling num-traits v0.2.19
     Compiling quote v1.0.40
     Compiling syn v2.0.100
     Compiling bytemuck_derive v1.9.3
     Compiling spirv-std-macros v0.9.0 (https://github.com/Rust-GPU/rust-gpu?rev=20052f89d932ee88aba118488fc79393c407e61c#20052f89)
     Compiling bitflags v1.3.2
     Compiling bytemuck v1.22.0
     Compiling glam v0.29.3
     Compiling spirv-std v0.9.0 (https://github.com/Rust-GPU/rust-gpu?rev=20052f89d932ee88aba118488fc79393c407e61c#20052f89)
     Compiling shared v0.0.0 (/home/ky/Repos/rust-gpu/rust-gpu-shadertoys/shared)
     Compiling shadertoys-shaders v0.0.0 (/home/ky/Repos/rust-gpu/rust-gpu-shadertoys/shaders)
  warning: method `zero` is never used
     --> shaders/src/raymarching_primitives.rs:366:8
      |
  365 | impl Inputs {
      | ----------- method in this implementation
  366 |     fn zero(&self) -> i32 {
      |        ^^^^
      |
      = note: `#[warn(dead_code)]` on by default

  warning: error:0:0 - [VUID-StandaloneSpirv-None-10684] Invalid explicit layout decorations on type for operand '355[%_ptr_Function_bubble_buckey_balls__SurfaceData]'
             %1187 = OpVariable %_ptr_Function_bubble_buckey_balls__SurfaceData Function
    |
    = note: spirv-opt failed, leaving as unoptimized
    = note: module `/home/ky/Repos/rust-gpu/rust-gpu-shadertoys/target/spirv-builder/spirv-unknown-vulkan1.2/release/deps/shadertoys_shaders.spv`

  error: error:0:0 - [VUID-StandaloneSpirv-None-10684] Invalid explicit layout decorations on type for operand '355[%_ptr_Function_bubble_buckey_balls__SurfaceData]'
           %1187 = OpVariable %_ptr_Function_bubble_buckey_balls__SurfaceData Function
    |
    = note: spirv-val failed
    = note: module `/home/ky/Repos/rust-gpu/rust-gpu-shadertoys/target/spirv-builder/spirv-unknown-vulkan1.2/release/deps/shadertoys_shaders.spv`

  warning: `shadertoys-shaders` (lib) generated 2 warnings
  error: could not compile `shadertoys-shaders` (lib) due to 1 previous error; 2 warnings emitted
  Error: BuildFailed

[LegNeato]

Weird, I'll look into it!

[LegNeato]

Hmmm, I can't seem to repro this! I just updated rust-gpu, so perhaps it is fixed on master?

[ky-bean]

Unfortunately I am still seeing the build error on the latest from master. Did a clean git clone to be sure.

[ky-bean]

I am working off the assumption there's probably something wrong with the exact version of tools that Nix installs that rust-gpu & friends use to build the crates as I don't think there's any other reasonable explanation why I see build errors when you don't. The fact that I can't build with default features even with my change to build.rs points me to that conclusion. If it helps at all, it is a very long error log (too long to include in an issue comment), here is the result of compiling with default features: https://pastebin.com/JfJeHJ7X

So it's mostly repeated errors from somehow not being able to import stdlib.h which is a very bizarre issue to be having. I don't know why the build system can't find the standard library files, I've verified they exist & are in a path that the compiler checks for them in so I'm at a loss for trying to get the build to work with default features.

However with no default features & --features use-installed-tools I am seeing the same behavior as before: it doesn't build with that same error above, and changing the build.rs makes the build succeed.

I really don't know of any good troubleshooting steps from here to try to narrow down the issue on my own, if you have anything you'd like me to try I'd be happy to help how I can!

[ky-bean]

Unfortunately updating the Nix setup in #47 did not resolve this issue for me, however in my experiments I've found I can build & run rust-gpu's WGPU example runner (again, with --no--default-features --features use-installed-tools, use-compiled-tools still fails similarly to above), the example builds with the spirv-unknown-vulkan1.1 target, & I've checked it also runs with spirv-unknown-vulkan1.2 (the target rust-gpu-shadertoys uses) so I at least have a thread I can follow to see where the architecture of the two diverge.

Note that I am sorta flying by the seat of my pants with this process, and I don't have a whole lot of free time to devote to tracking this down. I would love to use this as a bit of a project to both learn about Rust-GPU's architectures and any areas (documentation probably?) that can be improved, but this won't happen quickly/soon. I don't think that would be an issue since this build failure seems to be mostly just a me problem but I just wanted to put that out there.