Internal Compiler Error in CTFE engine

[arturoc]

thread 'rustc' panicked at 'places should be checked on creation: InterpErrorInfo { kind: can't access mutable globals in ConstProp, backtrace: None }', src/librustc_mir/interpret/operand.rs:237:25
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/git.luolix.top-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/git.luolix.top-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:78
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1069
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1532
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:198
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:218
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:481
  12: rust_begin_unwind
             at src/libstd/panicking.rs:385
  13: core::panicking::panic_fmt
             at src/libcore/panicking.rs:89
  14: core::option::expect_none_failed
             at src/libcore/option.rs:1272
  15: rustc_mir::interpret::operand::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::try_read_immediate
  16: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::eval_rvalue_into_place
  17: <rustc_mir::transform::const_prop::ConstPropagator as rustc_middle::mir::visit::MutVisitor>::visit_statement
  18: <rustc_mir::transform::const_prop::ConstPropagator as rustc_middle::mir::visit::MutVisitor>::visit_body
  19: <rustc_mir::transform::const_prop::ConstProp as rustc_mir::transform::MirPass>::run_pass
  20: rustc_mir::transform::run_passes
  21: rustc_mir::transform::run_optimization_passes
  22: rustc_mir::transform::optimized_mir
  23: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  24: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  25: rustc_query_system::query::plumbing::get_query
  26: rustc_mir::monomorphize::collector::collect_items_rec
  27: rustc_mir::monomorphize::collector::collect_items_rec
  28: rustc_mir::monomorphize::collector::collect_items_rec
  29: rustc_mir::monomorphize::collector::collect_items_rec
  30: rustc_mir::monomorphize::collector::collect_items_rec
  31: rustc_mir::monomorphize::collector::collect_items_rec
  32: rustc_mir::monomorphize::collector::collect_items_rec
  33: rustc_mir::monomorphize::collector::collect_items_rec
  34: rustc_session::utils::<impl rustc_session::session::Session>::time
  35: rustc_mir::monomorphize::collector::collect_crate_mono_items
  36: rustc_mir::monomorphize::partitioning::collect_and_partition_mono_items
  37: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::collect_and_partition_mono_items>::compute
  38: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  39: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  40: rustc_query_system::query::plumbing::get_query
  41: rustc_codegen_ssa::base::codegen_crate
  42: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate
  43: rustc_interface::passes::start_codegen
  44: rustc_middle::ty::context::tls::enter_global
  45: rustc_interface::queries::Queries::ongoing_codegen
  46: rustc_interface::interface::run_compiler_in_existing_thread_pool
  47: scoped_tls::ScopedKey<T>::set
  48: rustc_ast::attr::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.45.0-nightly (fa51f810e 2020-04-29) running on x86_64-unknown-linux-gnu

note: compiler flags: -C opt-level=3 -C bitcode-in-rlib=no -C codegen-units=16 -C debuginfo=2 -C incremental -C link-arg=-fuse-ld=lld --crate-type lib

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [optimized_mir] processing `window::glfw_window::EventsPoll::new`
#1 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack

The specified method, EventsPoll::new looks like:

static mut GLFW: Option<glfw::Glfw> = None;
pub fn new() -> Result<EventsPoll>{
        //TODO: Give the option to choose FAIL / LOG?
        let glfw = unsafe{ if let Some(glfw) = GLFW {
            glfw
        }else{
            let glfw = glfw::init(glfw::LOG_ERRORS)
                .map_err(|e| util::Error::with_cause("Error initializing glfw", e))?;
            GLFW = Some(glfw);
            glfw
        }};

        Ok(EventsPoll( Arc::new( RwLock::new(EventsPollData{
            glfw,
            should_close: 1,
        }))))
}

might be related with the static mut?, but haven't tried to replicate it on a smaller example, will report back if i do so

[jonas-schievink]

cc @wesleywiser @felix91gr

Would be good to find out if this was caused by #71518, and to find an MCVE, so:

@rustbot ping cleanup

[rustbot]

Hey Cleanup Crew ICE-breakers! This bug has been identified as a good
"Cleanup ICE-breaking candidate". In case it's useful, here are some
instructions for tackling these sorts of bugs. Maybe take a look?
Thanks! <3

cc @AminArria @chrissimpkins @contrun @DutchGhost @elshize @ethanboxx @h-michael @HallerPatrick @hdhoang @hellow554 @imtsuki @jakevossen5 @kanru @KarlK90 @LeSeulArtichaut @MAdrianMattocks @matheus-consoli @mental32 @nmccarty @Noah-Kennedy @pard68 @PeytonT @pierreN @Redblueflame @RobbieClarken @RobertoSnap @robjtede @SarthakSingh31 @senden9 @shekohex @sinato @spastorino @turboladen @woshilapin @yerke

[felix91gr]

Imma try to bisect this, it's as good an opportunity as any to learn about it!

[wesleywiser]

@felix91gr here's a minimal example that is self-contained and shows the issue:

use std::sync::{Arc, RwLock};

#[derive(Copy, Clone)]
pub struct Glfw;

fn fun_call<T>(val: T) -> T { val }

static mut GLFW: Option<Glfw> = None;
pub fn new() -> Result<Arc<RwLock<Glfw>>, Box<dyn std::error::Error>> {
    //TODO: Give the option to choose FAIL / LOG?
    let glfw = unsafe { if let Some(glfw) = GLFW {
        glfw
    } else {
        let glfw = fun_call(Glfw);
        GLFW = Some(glfw);
        glfw
    }};

    Ok(Arc::new(RwLock::new(glfw)))
}

[felix91gr]

Bisect shows the ICE was introduced between the nightlies of the 26th (no ICE) and the 27th (ICE is present).

My pc is trying to find the particular commit still, but if that takes too long (like if it has to compile rustc (I have no idea, this is my first time bisecting)) I'll leave it to people with beefier computers :3

That said, @jonas-schievink I think you can at least rest assured-ish because our PR was merged on the 29th (according to Github).

[LeSeulArtichaut]

Minimized a bit further:

#[derive(Copy, Clone)]
pub struct Glfw;

static mut GLFW: Option<Glfw> = None;
pub fn new() -> Glfw {
    unsafe { if let Some(glfw) = GLFW {
        return glfw;
    } else {
        todo!()
    }};
}

[felix91gr]

Wait, bisect just finished. 😆

---

Regression found in the compiler

searched nightlies: from nightly-2020-04-26 to nightly-2020-04-28
regressed nightly: nightly-2020-04-27
searched commits: from 0862458 to e83f756
regressed commit: b592b37
source code:

#[derive(Copy, Clone)]
pub struct Glfw;

static mut GLFW: Option<Glfw> = None;
pub fn new() -> Glfw {
    unsafe { if let Some(glfw) = GLFW {
        return glfw;
    } else {
        todo!()
    }};
}

Instructions

Please give the steps for how to build your repository (platform, system dependencies, etc.)

Error

COLLAPSIBLE ERROR STACKTRACE

thread 'rustc' panicked at 'places should be checked on creation: InterpErrorInfo { kind: can't access mutable globals in ConstProp, backtrace: None }', src/librustc_mir/interpret/operand.rs:237:25
stack backtrace:
   0:     0x7f8826db9ba4 - backtrace::backtrace::libunwind::trace::he144fab28a4aed2d
                               at /cargo/registry/src/git.luolix.top-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
   1:     0x7f8826db9ba4 - backtrace::backtrace::trace_unsynchronized::h54d2de49d4561d5b
                               at /cargo/registry/src/git.luolix.top-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
   2:     0x7f8826db9ba4 - std::sys_common::backtrace::_print_fmt::hc03d55f811cceef4
                               at src/libstd/sys_common/backtrace.rs:78
   3:     0x7f8826db9ba4 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hbc44d25334fa89cd
                               at src/libstd/sys_common/backtrace.rs:59
   4:     0x7f8826df81bc - core::fmt::write::hdf236390fbd68d3d
                               at src/libcore/fmt/mod.rs:1069
   5:     0x7f8826dab5b3 - std::io::Write::write_fmt::h4ee562ef1f300991
                               at src/libstd/io/mod.rs:1532
   6:     0x7f8826dbeba5 - std::sys_common::backtrace::_print::hc4186a5ac838159c
                               at src/libstd/sys_common/backtrace.rs:62
   7:     0x7f8826dbeba5 - std::sys_common::backtrace::print::h61fb789361bb8109
                               at src/libstd/sys_common/backtrace.rs:49
   8:     0x7f8826dbeba5 - std::panicking::default_hook::{{closure}}::hcd876594d255c932
                               at src/libstd/panicking.rs:198
   9:     0x7f8826dbe8e2 - std::panicking::default_hook::hfc205bc5ce834a89
                               at src/libstd/panicking.rs:218
  10:     0x7f882735c9d3 - rustc_driver::report_ice::h425ff32f2997b1b0
  11:     0x7f8826dbf325 - std::panicking::rust_panic_with_hook::h98fcd55ca23bf6e3
                               at src/libstd/panicking.rs:481
  12:     0x7f8826dbee3b - rust_begin_unwind
                               at src/libstd/panicking.rs:385
  13:     0x7f8826df4e51 - core::panicking::panic_fmt::hd101a87121fa411f
                               at src/libcore/panicking.rs:89
  14:     0x7f8826df4ac3 - core::option::expect_none_failed::h4f0e89faa3179bf7
                               at src/libcore/option.rs:1272
  15:     0x7f88286c4ee0 - rustc_mir::interpret::operand::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::try_read_immediate::h9e5d69914fbd3305
  16:     0x7f88286ef1df - rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::eval_rvalue_into_place::hecfa8b086a9d5954
  17:     0x7f88283e5fac - <rustc_mir::transform::const_prop::ConstPropagator as rustc_middle::mir::visit::MutVisitor>::visit_statement::h80dfc90527f8a7a5
  18:     0x7f88283e590c - <rustc_mir::transform::const_prop::ConstPropagator as rustc_middle::mir::visit::MutVisitor>::visit_body::hd6bf873cbd2afe4a
  19:     0x7f88283e362a - <rustc_mir::transform::const_prop::ConstProp as rustc_mir::transform::MirPass>::run_pass::h9fa8545e88cf213f
  20:     0x7f88287c4bcc - rustc_mir::transform::run_passes::h86f06e2b0f09c282
  21:     0x7f88287c5f34 - rustc_mir::transform::run_optimization_passes::h1069117249cb0b38
  22:     0x7f88287c616f - rustc_mir::transform::optimized_mir::h4ec71b75d2a6bf1a
  23:     0x7f8829795de1 - rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::h5b1025130185b1f3
  24:     0x7f88297dcc67 - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h2e128a35d7b49968
  25:     0x7f88299c5ab3 - rustc_query_system::query::plumbing::get_query::h828844368b6e29fa
  26:     0x7f882866fb4d - rustc_mir::monomorphize::collector::collect_items_rec::h09e92850b75eeb5a
  27:     0x7f88285b1553 - rustc_session::utils::<impl rustc_session::session::Session>::time::hd67751bc12e8f569
  28:     0x7f882866e7ac - rustc_mir::monomorphize::collector::collect_crate_mono_items::he88f6c023e895d70
  29:     0x7f8828704942 - rustc_mir::monomorphize::partitioning::collect_and_partition_mono_items::hcddfe42969bb55db
  30:     0x7f88288fe322 - rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::collect_and_partition_mono_items>::compute::h74a163faf8fa9fa4
  31:     0x7f88289486a9 - rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::h33492783e319a700
  32:     0x7f8828933e24 - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::hc1a904633c4769f0
  33:     0x7f8828911b11 - rustc_query_system::query::plumbing::get_query::h62e5953c75e544e4
  34:     0x7f88288d3378 - rustc_codegen_ssa::back::symbol_export::exported_symbols_provider_local::h4c53d11aabad0ab4
  35:     0x7f8828be0eee - rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::exported_symbols>::compute::hd61caafb6202bfed
  36:     0x7f8828b162d3 - rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::hd1c4539b0ad19f6b
  37:     0x7f8828c3aab5 - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h393ecb9f06efde8d
  38:     0x7f8828c0fac9 - rustc_query_system::query::plumbing::get_query::h824de524a506526f
  39:     0x7f8828bdcbcc - rustc_metadata::rmeta::encoder::encode_metadata_impl::hd04d894906804c23
  40:     0x7f8828c7510c - rustc_data_structures::sync::join::h2e3de323c6c055ae
  41:     0x7f8828ca82b0 - rustc_metadata::rmeta::decoder::cstore_impl::<impl rustc_middle::middle::cstore::CrateStore for rustc_metadata::creader::CStore>::encode_metadata::hbbf7378b0f89abc0
  42:     0x7f882966ef60 - rustc_middle::ty::context::TyCtxt::encode_metadata::h4390b9d0eedad1d1
  43:     0x7f88276f5b2e - rustc_interface::passes::start_codegen::hf3eb84427919bf3f
  44:     0x7f8827602b49 - rustc_middle::ty::context::tls::enter_global::h1712f97c17be1c1a
  45:     0x7f88277004c6 - rustc_interface::queries::Queries::ongoing_codegen::h97f0905c2e49e248
  46:     0x7f88274b1731 - rustc_interface::interface::run_compiler_in_existing_thread_pool::hc5186ff1ae47163e
  47:     0x7f882736651d - scoped_tls::ScopedKey<T>::set::h8d9d472e8b3cd3fa
  48:     0x7f8827363a14 - rustc_ast::attr::with_globals::hc6db6365f3099bf0
  49:     0x7f882736e76e - std::sys_common::backtrace::__rust_begin_short_backtrace::h8b9b12138841a09f
  50:     0x7f88274b364e - core::ops::function::FnOnce::call_once{{vtable.shim}}::h90c923a0b1c604b3
  51:     0x7f8826dcf3aa - <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once::h314c63ae4ebdec44
                               at /rustc/fa51f810e5b9254904b92660e7280b7d6a46f112/src/liballoc/boxed.rs:1034
  52:     0x7f8826dcf3aa - <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once::hd1e953b7b8bd01ff
                               at /rustc/fa51f810e5b9254904b92660e7280b7d6a46f112/src/liballoc/boxed.rs:1034
  53:     0x7f8826dcf3aa - std::sys::unix::thread::Thread::new::thread_start::hb0fc8ed9cb1fd36f
                               at src/libstd/sys/unix/thread.rs:87
  54:     0x7f8826b336db - start_thread
                               at /build/glibc-OTsEL5/glibc-2.27/nptl/pthread_create.c:463
  55:     0x7f882645088f - __clone
  56:                0x0 - <unknown>

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.45.0-nightly (fa51f810e 2020-04-29) running on x86_64-unknown-linux-gnu

note: compiler flags: -C bitcode-in-rlib=no -C debuginfo=2 -C incremental --crate-type lib

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [optimized_mir] processing `new`
#1 [collect_and_partition_mono_items] collect_and_partition_mono_items
#2 [exported_symbols] exported_symbols
end of query stack

[felix91gr]

(working on the stack trace)

[LeSeulArtichaut]

@felix91gr Use the cargo-bisect-rustc tool, which fetches the artifacts generated by @bors when testing a PR. Your CPU will be way happier :D

[felix91gr]

@felix91gr Use the cargo-bisect-rustc tool, which fetches the artifacts generated by @bors when testing a PR. Your CPU will be way happier :D

Yaaas that's precisely what I used. It's sooooo goooooood ✨

[LeSeulArtichaut]

(I haven't been able to minimize since my last comment, so I think it is now minimal)

[felix91gr]

Awesome. I'll bisect again with that one. For now, I've added the full backtrace taken from today's nightly to the bisect report. Do you know how I can compile using a specific rustc's commit? (I just did rustup update and used cargo +nightly build, which used today's nightly.

[LeSeulArtichaut]

@felix91gr Now we know which PR regressed (#71566). It's a rollup of multiple PRs, so we'll need to guess which one is the culprit using the power of deduction :D

Here I'm pretty sure this has been caused by #71140, cc @oli-obk

[felix91gr]

Kay, I'll leave it to Oli then. He knows way more than I do about static initialization soundness :D also, it's (apparently) his PR.

I've done one last test: did bisect with your minimal counterexample, which ICE'd on the same commit. I've edited the bisection report to have your mcve and its backtrace :3 @jonas-schievink

[pnkfelix]

@felix91gr Now we know which PR regressed (#71566). It's a rollup of multiple PRs, so we'll need to guess which one is the culprit using the power of deduction :D

I cannot tell if you are being facetious here, but there is the option of bisecting over the individual PR's in the rollup itself, e.g. via git bisect directly on a local rust checkout. It is unfortunate that we don't have a way to do that mechanically within cargo-bisect-rustc itself (which would be a huge undertaking)

[wesleywiser]

From some local testing, I can confirm that reverting af44cdf from #71140 fixes the ICE.

cc @oli-obk

[pnkfelix]

@wesleywiser yeah I think @oli-obk posted PR #71751 which essentially reverted af44cdf by moving the check elsewhere (so that we still get the fix that #71140 was trying to land).

Its just waiting review; I looked at it briefly but I'm not an expert on that code so I'm going to wait for @RalfJung to look at it.

[LeSeulArtichaut]

I cannot tell if you are being facetious here, but there is the option of bisecting over the individual PR's in the rollup itself

Right, that sentence was unclear, sorry about that. I just wrote something quickly, to tell @felix91gr that they didn't need to bisect every PR in the rollup, that would have been a waste of time.

[felix91gr]

I cannot tell if you are being facetious here, but there is the option of bisecting over the individual PR's in the rollup itself

Right, that sentence was unclear, sorry about that. I just wrote something quickly, to tell @felix91gr that they didn't need to bisect every PR in the rollup, that would have been a waste of time.

@LeSeulArtichaut it's completely fine! I got your friendly tone when you posted it. The :D was very helpful in that regard 🌈 🙂