-Zrandomize-layout causes ICE when compiling syn (as part of a test) (with --target)

[saethlin]

$ cargo download -x prettier-please

$ RUSTFLAGS="-Zrandomize-layout" cargo +nightly test --target=x86_64-unknown-linux-gnu --lib

rustc --version --verbose:

rustc 1.72.0-nightly (1c53407e8 2023-05-28)
binary: rustc
commit-hash: 1c53407e8c7cc922d718bde61ca34f47b6d2120f
commit-date: 2023-05-28
host: x86_64-unknown-linux-gnu
release: 1.72.0-nightly
LLVM version: 16.0.4

Error:

thread 'rustc' panicked at 'assertion failed: target_offset >= offset', compiler/rustc_codegen_llvm/src/type_of.rs:126:9

Backtrace

thread 'rustc' panicked at 'assertion failed: target_offset >= offset', compiler/rustc_codegen_llvm/src/type_of.rs:126:9
stack backtrace:
   0:     0x7f48a6969921 - std::backtrace_rs::backtrace::libunwind::trace::h2f87d9d5f9ce82d6
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f48a6969921 - std::backtrace_rs::backtrace::trace_unsynchronized::h43da12aa2b9d3c2f
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f48a6969921 - std::sys_common::backtrace::_print_fmt::hce2fdf626ac693ef
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7f48a6969921 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h2c0bda5382415c6f
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f48a69ca31f - core::fmt::rt::Argument::fmt::ha8dced8dec8d37aa
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/core/src/fmt/rt.rs:138:9
   5:     0x7f48a69ca31f - core::fmt::write::h77d649aab618411d
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/core/src/fmt/mod.rs:1094:21
   6:     0x7f48a695cb11 - std::io::Write::write_fmt::h30551196154004c0
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/io/mod.rs:1713:15
   7:     0x7f48a6969735 - std::sys_common::backtrace::_print::h8e2356bc7d163cad
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f48a6969735 - std::sys_common::backtrace::print::ha0cb1b28bf8aa788
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f48a696c3f7 - std::panicking::default_hook::{{closure}}::h87bda075dafc0a5c
  10:     0x7f48a696c1e4 - std::panicking::default_hook::h68a37beb1a2d6a14
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/panicking.rs:288:9
  11:     0x7f48a9b1e64b - rustc_driver_impl[7659d0211759c851]::install_ice_hook::{closure#0}
  12:     0x7f48a696cb3d - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::he0663d30994fe530
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/alloc/src/boxed.rs:1999:9
  13:     0x7f48a696cb3d - std::panicking::rust_panic_with_hook::hd2f9c684d5205393
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/panicking.rs:709:13
  14:     0x7f48a696c891 - std::panicking::begin_panic_handler::{{closure}}::h1aa3874266ff3595
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/panicking.rs:595:13
  15:     0x7f48a6969d56 - std::sys_common::backtrace::__rust_end_short_backtrace::h7f2be3d4a5840a45
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/sys_common/backtrace.rs:151:18
  16:     0x7f48a696c622 - rust_begin_unwind
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/panicking.rs:593:5
  17:     0x7f48a69c65a3 - core::panicking::panic_fmt::h38dc6fd12db28774
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/core/src/panicking.rs:67:14
  18:     0x7f48a69c6633 - core::panicking::panic::hc4f30bfaae186a6f
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/core/src/panicking.rs:117:5
  19:     0x7f48a7d20534 - rustc_codegen_llvm[454dee9a5a35a59a]::type_of::struct_llfields
  20:     0x7f48a7d1d777 - <rustc_target[a32af95a14d1468e]::abi::TyAndLayout<rustc_middle[9e72259b1eea478a]::ty::Ty> as rustc_codegen_llvm[454dee9a5a35a59a]::type_of::LayoutLlvmExt>::llvm_type
  21:     0x7f48a8581fac - <rustc_codegen_ssa[ab281534f5d7966c]::mir::FunctionCx<rustc_codegen_llvm[454dee9a5a35a59a]::builder::Builder>>::codegen_rvalue
  22:     0x7f48a8525834 - rustc_codegen_ssa[ab281534f5d7966c]::mir::codegen_mir::<rustc_codegen_llvm[454dee9a5a35a59a]::builder::Builder>
  23:     0x7f48a914b3eb - rustc_codegen_llvm[454dee9a5a35a59a]::base::compile_codegen_unit::module_codegen
  24:     0x7f48a9148909 - <rustc_codegen_llvm[454dee9a5a35a59a]::LlvmCodegenBackend as rustc_codegen_ssa[ab281534f5d7966c]::traits::backend::ExtraBackendMethods>::compile_codegen_unit
  25:     0x7f48a91462b7 - rustc_codegen_ssa[ab281534f5d7966c]::base::codegen_crate::<rustc_codegen_llvm[454dee9a5a35a59a]::LlvmCodegenBackend>
  26:     0x7f48a9145bbb - <rustc_codegen_llvm[454dee9a5a35a59a]::LlvmCodegenBackend as rustc_codegen_ssa[ab281534f5d7966c]::traits::backend::CodegenBackend>::codegen_crate
  27:     0x7f48a8d95621 - rustc_interface[45420231614740cd]::passes::start_codegen
  28:     0x7f48a8d9232d - <rustc_middle[9e72259b1eea478a]::ty::context::GlobalCtxt>::enter::<<rustc_interface[45420231614740cd]::queries::Queries>::ongoing_codegen::{closure#0}::{closure#0}, core[7efe0b4e56e81f9a]::result::Result<alloc[463a1543fa81c36a]::boxed::Box<dyn core[7efe0b4e56e81f9a]::any::Any>, rustc_span[2bf001af0057410c]::ErrorGuaranteed>>
  29:     0x7f48a8d912ad - <rustc_interface[45420231614740cd]::queries::Queries>::ongoing_codegen
  30:     0x7f48a8d908c9 - <rustc_interface[45420231614740cd]::interface::Compiler>::enter::<rustc_driver_impl[7659d0211759c851]::run_compiler::{closure#1}::{closure#2}, core[7efe0b4e56e81f9a]::result::Result<core[7efe0b4e56e81f9a]::option::Option<rustc_interface[45420231614740cd]::queries::Linker>, rustc_span[2bf001af0057410c]::ErrorGuaranteed>>
  31:     0x7f48a8d8e093 - std[1f5a572b0fe1d489]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[45420231614740cd]::util::run_in_thread_pool_with_globals<rustc_interface[45420231614740cd]::interface::run_compiler<core[7efe0b4e56e81f9a]::result::Result<(), rustc_span[2bf001af0057410c]::ErrorGuaranteed>, rustc_driver_impl[7659d0211759c851]::run_compiler::{closure#1}>::{closure#0}, core[7efe0b4e56e81f9a]::result::Result<(), rustc_span[2bf001af0057410c]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[7efe0b4e56e81f9a]::result::Result<(), rustc_span[2bf001af0057410c]::ErrorGuaranteed>>
  32:     0x7f48a93ba1f5 - <<std[1f5a572b0fe1d489]::thread::Builder>::spawn_unchecked_<rustc_interface[45420231614740cd]::util::run_in_thread_pool_with_globals<rustc_interface[45420231614740cd]::interface::run_compiler<core[7efe0b4e56e81f9a]::result::Result<(), rustc_span[2bf001af0057410c]::ErrorGuaranteed>, rustc_driver_impl[7659d0211759c851]::run_compiler::{closure#1}>::{closure#0}, core[7efe0b4e56e81f9a]::result::Result<(), rustc_span[2bf001af0057410c]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[7efe0b4e56e81f9a]::result::Result<(), rustc_span[2bf001af0057410c]::ErrorGuaranteed>>::{closure#1} as core[7efe0b4e56e81f9a]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  33:     0x7f48a6977065 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h3b74af01aa4409e3
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/alloc/src/boxed.rs:1985:9
  34:     0x7f48a6977065 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h6fd53215ad4052a6
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/alloc/src/boxed.rs:1985:9
  35:     0x7f48a6977065 - std::sys::unix::thread::Thread::new::thread_start::h8df08f1507529c34
                               at /rustc/1c53407e8c7cc922d718bde61ca34f47b6d2120f/library/std/src/sys/unix/thread.rs:108:17
  36:     0x7f48a671144b - <unknown>
  37:     0x7f48a6794e40 - <unknown>
  38:                0x0 - <unknown>

[jyn514]

I take it the RUSTDOCFLAGS here are not actually relevant, since this is crashing in LLVM? So something like RUSTFLAGS="-Zrandomize-layout" cargo +nightly test --target=x86_64-unknown-linux-gnu -j1 --lib would be a more minimal reproduction?

[saethlin]

Yes. Updated the issue description.

[trevyn]

Related / dupe of #101646