blake3 difftest

[Firestar99]

blake3 is failing with a bunch of ICEs, see #312. This is a repro of the failure within out difftest framework, so that a fix can be developed.

black_box error:

error: internal compiler error: /Users/runner/work/rust-gpu/rust-gpu/tests/difftests/tests/target/release/build/rustc_codegen_spirv-46ee035126448e6d/out/pqp_cg_ssa/src/mir/block.rs:956:29: intrinsic black_box must be overridden by codegen backend, but isn't
test difftests::blake3 ... 2025-07-07T13:16:50.839901Z ERROR difftests::runner: Cargo execution failed for package 'blake3-rust-gpu'
   --> /Users/runner/.rustup/toolchains/nightly-2024-11-22-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/hint.rs:389:5
    |
389 |     crate::intrinsics::black_box(dummy)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

thread 'rustc' panicked at /Users/runner/work/rust-gpu/rust-gpu/tests/difftests/tests/target/release/build/rustc_codegen_spirv-46ee035126448e6d/out/pqp_cg_ssa/src/mir/block.rs:956:29:
Box<dyn Any>
stack backtrace:
   Compiling spirv-std-macros v0.9.0 (/Users/runner/work/rust-gpu/rust-gpu/crates/spirv-std/macros)
   0:        0x10eaf527c - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h447e736edf25ff33
   1:        0x10bd155e0 - core::fmt::write::hf4d022d9ef02167e
   2:        0x10eae9428 - std::io::Write::write_fmt::h11757e8bc697ea8e
   3:        0x10eaf513c - std::sys::backtrace::BacktraceLock::print::haf4ac7c7af3cf97a
   4:        0x10eaf7610 - std::panicking::default_hook::{{closure}}::h52aa610c7cde4596
   5:        0x10eaf7458 - std::panicking::default_hook::hdcfc7f1ad8d891f0
   6:        0x10c934bb0 - <alloc[e2e5e8515d00274d]::boxed::Box<rustc_driver_impl[c6ade677a6b0e20c]::install_ice_hook::{closure#0}> as core[924c651d484e1a25]::ops::function::Fn<(&dyn for<'a, 'b> core[924c651d484e1a25]::ops::function::Fn<(&'a std[fc297465fa958267]::panic::PanicHookInfo<'b>,), Output = ()> + core[924c651d484e1a25]::marker::Send + core[924c651d484e1a25]::marker::Sync, &std[fc297465fa958267]::panic::PanicHookInfo)>>::call
   7:        0x10c934bb0 - <alloc[e2e5e8515d00274d]::boxed::Box<rustc_driver_impl[c6ade677a6b0e20c]::install_ice_hook::{closure#0}> as core[924c651d484e1a25]::ops::function::Fn<(&dyn for<'a, 'b> core[924c651d484e1a25]::ops::function::Fn<(&'a std[fc297465fa958267]::panic::PanicHookInfo<'b>,), Output = ()> + core[924c651d484e1a25]::marker::Send + core[924c651d484e1a25]::marker::Sync, &std[fc297465fa958267]::panic::PanicHookInfo)>>::call
   8:        0x10eaf7edc - std::panicking::rust_panic_with_hook::heb73fc7746f92ba7
   9:        0x10c9d9718 - std[fc297465fa958267]::panicking::begin_panic::<rustc_errors[caf545eadef7fdd]::ExplicitBug>::{closure#0}
  10:        0x10c9d94d0 - std[fc297465fa958267]::sys::backtrace::__rust_end_short_backtrace::<std[fc297465fa958267]::panicking::begin_panic<rustc_errors[caf545eadef7fdd]::ExplicitBug>::{closure#0}, !>
  11:        0x11125c04c - std[fc297465fa958267]::panicking::begin_panic::<rustc_errors[caf545eadef7fdd]::ExplicitBug>
  12:        0x10c9dfad4 - <rustc_errors[caf545eadef7fdd]::diagnostic::BugAbort as rustc_errors[caf545eadef7fdd]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  13:        0x102cd621c - <unknown>
  14:        0x102b37588 - <unknown>
  15:        0x102b374b0 - <unknown>
  16:        0x102b3747c - <unknown>
  17:        0x1031b65c0 - <unknown>
  18:        0x102dc1b50 - <unknown>
  19:        0x102dd05f4 - <unknown>
  20:        0x102cca2b4 - <unknown>
  21:        0x102d6fa90 - <unknown>
  22:        0x102c3693c - <unknown>
  23:        0x102c364a0 - <unknown>
  24:        0x102ccb650 - <unknown>
  25:        0x102c35638 - <unknown>
  26:        0x10d1cbad8 - <rustc_session[3e2f7db2cc04b493]::session::Session>::time::<alloc[e2e5e8515d00274d]::boxed::Box<dyn core[924c651d484e1a25]::any::Any>, rustc_interface[fb6f1569d3f1850c]::passes::start_codegen::{closure#0}>
  27:        0x10d2fadd4 - rustc_interface[fb6f1569d3f1850c]::passes::start_codegen
  28:        0x10d2885f0 - <rustc_interface[fb6f1569d3f1850c]::queries::Linker>::codegen_and_build_linker
  29:        0x10c91dd20 - <rustc_middle[dc5a577fd6f5eb51]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[c6ade677a6b0e20c]::run_compiler::{closure#0}::{closure#1}::{closure#7}, core[924c651d484e1a25]::result::Result<core[924c651d484e1a25]::option::Option<rustc_interface[fb6f1569d3f1850c]::queries::Linker>, rustc_span[60df94d8028129a3]::ErrorGuaranteed>>
  30:        0x10c8e51b0 - <rustc_interface[fb6f1569d3f1850c]::interface::Compiler>::enter::<rustc_driver_impl[c6ade677a6b0e20c]::run_compiler::{closure#0}::{closure#1}, core[924c651d484e1a25]::result::Result<core[924c651d484e1a25]::option::Option<rustc_interface[fb6f1569d3f1850c]::queries::Linker>, rustc_span[60df94d8028129a3]::ErrorGuaranteed>>
  31:        0x10c927588 - rustc_span[60df94d8028129a3]::create_session_globals_then::<core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>, rustc_interface[fb6f1569d3f1850c]::util::run_in_thread_with_globals<rustc_interface[fb6f1569d3f1850c]::util::run_in_thread_pool_with_globals<rustc_interface[fb6f1569d3f1850c]::interface::run_compiler<core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>, rustc_driver_impl[c6ade677a6b0e20c]::run_compiler::{closure#0}>::{closure#1}, core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>>::{closure#0}, core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>>::{closure#0}::{closure#0}::{closure#0}>
  32:        0x10c90f588 - std[fc297465fa958267]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[fb6f1569d3f1850c]::util::run_in_thread_with_globals<rustc_interface[fb6f1569d3f1850c]::util::run_in_thread_pool_with_globals<rustc_interface[fb6f1569d3f1850c]::interface::run_compiler<core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>, rustc_driver_impl[c6ade677a6b0e20c]::run_compiler::{closure#0}>::{closure#1}, core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>>::{closure#0}, core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>>
  33:        0x10c912b54 - <<std[fc297465fa958267]::thread::Builder>::spawn_unchecked_<rustc_interface[fb6f1569d3f1850c]::util::run_in_thread_with_globals<rustc_interface[fb6f1569d3f1850c]::util::run_in_thread_pool_with_globals<rustc_interface[fb6f1569d3f1850c]::interface::run_compiler<core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>, rustc_driver_impl[c6ade677a6b0e20c]::run_compiler::{closure#0}>::{closure#1}, core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>>::{closure#0}, core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[924c651d484e1a25]::result::Result<(), rustc_span[60df94d8028129a3]::ErrorGuaranteed>>::{closure#1} as core[924c651d484e1a25]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  34:        0x10eb01fe8 - std::sys::pal::unix::thread::Thread::new::thread_start::h5a3f92a0fdbf8eb0
  35:        0x18525ef94 - __pthread_joiner_wake

memset error, only locally observed:

error: memset on structs not implemented yet
   --> /home/firestar99/.cargo/registry/src/index.crates.io-6f17d22bba15001f/blake3-1.8.2/src/lib.rs:552:17
    |
552 |                 self.buf = [0; BLOCK_LEN];
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^

pub const BLOCK_LEN: usize = 64;
let buf: [u8; BLOCK_LEN];
buf = [0; BLOCK_LEN]; // self removed

[LegNeato]

Do we want this as a difftest? Should we create runtime tests using similar / the same stuff but not requiring a different impl to diff against?

[Firestar99]

I was considering that... but when testing libs, it's probably still best to difftest it against calling the entry point from the CPU, to see if the GPU code may have mispiled somehow.