Fix SGX RWLock representation for UnsafeCell niche fix #1

jethrogb · 2020-01-31T14:21:02Z

jethrogb · 2020-01-31T14:22:24Z

eddyb · 2020-01-31T19:02:16Z

src/libstd/sys/sgx/rwlock.rs

@@ -239,7 +241,7 @@ mod tests {
            zero_stack();
            let mut init = MaybeUninit::<RWLock>::zeroed();
            rwlock_new(&mut init);
-            assert_eq!(mem::transmute::<_, [u8; 128]>(init.assume_init()).as_slice(), RWLOCK_INIT)
+            assert_eq!(mem::transmute::<_, [u8; 144]>(init.assume_init()).as_slice(), RWLOCK_INIT)


I don't really understand this test, and it's "zero the stack" thing - if some bytes are uninitialized, the comparison is UB, and there's no real way around that (without the proposed LLVM freeze operation), AFAIK.

And MaybeUninit::<RWLock>::zeroed() has the same semantics as [0u8; 144], doesn't it? So there's no way any bytes wouldn't be zeroed.

I know this is offtopic, but I'm a bit worried this test (and perhaps more like it?) isn't actually testing what it's supposed to (cc @RalfJung)

I don't really understand this test, and it's "zero the stack" thing

transmute::<_, RWLock>(*RWLOCK_INIT) needs to be equivalent to RWLock::new(). This test tries to assert that. Since part of the representation of RWLock::new() may contain uninitialized memory, some trickery (and UB) is needed, but this (trying very hard to get the uninitialized memory to be 0) is the best we can do.

if some bytes are uninitialized, the comparison is UB, and there's no real way around that (without the proposed LLVM freeze operation), AFAIK.

Yes, this is exactly what the comment just above this code block tries to explain (“issue with the test code”). However, this test has been working fine and this is the best we can do (I think? Happy to hear alternatives!). If changes to codegen are made that make this test fail, we can consider other options at that time. Note that UB only occurs during the execution of this test, normal use of this primitive never uses uninitialized memory.

And MaybeUninit::::zeroed() has the same semantics as [0u8; 144], doesn't it? So there's no way any bytes wouldn't be zeroed.

I'm not sure what you mean by this. Where are we using [0u8; 144]?

And MaybeUninit::::zeroed() has the same semantics as [0u8; 144], doesn't it?

It's not; the former resets any padding to Undef as happens any time a struct is copied.

Note that UB only occurs during the execution of this test, normal use of this primitive never uses uninitialized memory.

If the test deliberately causes UB, it should have a comment saying that.

It's not; the former resets any padding to Undef as happens any time a struct is copied.

Oh right I forgot about that (sadly we don't tell LLVM about this, since we just use a plain memcpy).

Wouldn't that also imply that it's impossible for RWLock::new() to guarantee the padding bytes of RWLock are initialized to 0, which this tests tries to prove (and arguably fails because its comparison of undef bytes is UB)?

Wouldn't that also imply that it's impossible for RWLock::new() to guarantee the padding bytes of RWLock are initialized to 0

Yes. (I am not sure if RwLock has any padding bytes, though.)

If we want to test for "no padding bytes", I wonder if this test should rely on const-eval instead, e.g. transmuting to [u8; 144] in a const, in a way that would cause an error if any of the bytes were undef.

@jethrogb is it crucial that RwLock::new() returns something all-0, or is it just crucial that using something all-0 instead of RwLock::new() must be fine? If the answer is the latter, when padding wouldn't actually be a problem (except for the test).

Okay turns out I was very misled by the "try hard to make sure" comment - it doesn't describe what is being tested, but specifically the zero_stack() call.

What this test appears to be checking is that the hardcoded bytes in RWLOCK_INIT (which presumably are also hardcoded on the C side) are the same as RWLock::new() ignoring padding.

But there's no way to automatically ignore padding, so what's being done here is trying to zero the stack space where RWLock::new() (and all of its transitive callers) writes every part of the RWLock, so that the padding likely stays zeroed.

I'm less worried about the test, but the comment could probably be improved to make it clearer that RWLock::new() having padding left uninitialized is not an issue, it just makes testing the initialized bytes harder.

I think the simplest way to get zeroed data (although I don't know how UB it is) is to use a static, e.g.: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=3abaa186579b5522baad9f492a784087 (that works even on stable, heh).

is it crucial that RwLock::new() returns something all-0, or is it just crucial that using something all-0 instead of RwLock::new() must be fine?

The latter

the comment could probably be improved

@eddyb I think you and @RalfJung have a pretty good idea of what I'm trying to achieve here, and you also have a better understanding of undef than I have, would you mind drafting a comment that makes sense to you?

I think the simplest way to get zeroed data (although I don't know how UB it is) is to use a static

Neat, I think this is a pretty good way.

would you mind drafting a comment that makes sense to you?

Well, if the static works, it's easier to explain that the undef parts will get zero-initialized in practice.

To be honest, one of the most confusing things to me was that zero_stack(); didn't have an empty line after it, which made me assume incorrectly what the comment referred to (if I remove the zero_stack() call, the test fails, and I think when I saw that I understood what the comment meant).

A static should be clearer from the start compared to zeroing the stack in an unguaranteed way.

…ing opaque return type Go from ``` error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements --> file8.rs:22:5 | 22 | / move || { 23 | | *dest = g.get(); 24 | | } | |_____^ | note: first, the lifetime cannot outlive the anonymous lifetime #1 defined on the function body at 18:1... --> file8.rs:18:1 | 18 | / fn bat<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a 19 | | where 20 | | G: Get<T> 21 | | { ... | 24 | | } 25 | | } | |_^ note: ...so that the types are compatible --> file8.rs:22:5 | 22 | / move || { //~ ERROR cannot infer an appropriate lifetime 23 | | *dest = g.get(); 24 | | } | |_____^ = note: expected `&mut T` found `&mut T` note: but, the lifetime must be valid for the lifetime `'a` as defined on the function body at 18:8... --> file8.rs:18:8 | 18 | fn bat<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a | ^^ note: ...so that return value is valid for the call --> file8.rs:18:45 | 18 | fn bat<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a | ^^^^^^^^^^^^^^^^^^^^^^^ ``` to ``` error[E0621]: explicit lifetime required in the type of `dest` --> file8.rs:18:45 | 18 | fn bat<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a | ------ ^^^^^^^^^^^^^^^^^^^^^^^ lifetime `'a` required | | | help: add explicit lifetime `'a` to the type of `dest`: `&'a mut T` ```

…ark-Simulacrum Improve SGX RWLock initializer test r? `@eddyb` This addresses pnkfelix#1 (comment) Fixes fortanix/rust-sgx#213

HWAddressSanitizer support # Motivation Compared to regular ASan, HWASan has a [smaller overhead](https://source.android.com/devices/tech/debug/hwasan). The difference in practice is that HWASan'ed code is more usable, e.g. Android device compiled with HWASan can be used as a daily driver. # Example ``` fn main() { let xs = vec![0, 1, 2, 3]; let _y = unsafe { *xs.as_ptr().offset(4) }; } ``` ``` ==223==ERROR: HWAddressSanitizer: tag-mismatch on address 0xefdeffff0050 at pc 0xaaaad00b3468 READ of size 4 at 0xefdeffff0050 tags: e5/00 (ptr/mem) in thread T0 #0 0xaaaad00b3464 (/root/main+0x53464) #1 0xaaaad00b39b4 (/root/main+0x539b4) #2 0xaaaad00b3dd0 (/root/main+0x53dd0) rust-lang#3 0xaaaad00b61dc (/root/main+0x561dc) rust-lang#4 0xaaaad00c0574 (/root/main+0x60574) rust-lang#5 0xaaaad00b6290 (/root/main+0x56290) rust-lang#6 0xaaaad00b6170 (/root/main+0x56170) rust-lang#7 0xaaaad00b3578 (/root/main+0x53578) rust-lang#8 0xffff81345e70 (/lib64/libc.so.6+0x20e70) rust-lang#9 0xaaaad0096310 (/root/main+0x36310) [0xefdeffff0040,0xefdeffff0060) is a small allocated heap chunk; size: 32 offset: 16 0xefdeffff0050 is located 0 bytes to the right of 16-byte region [0xefdeffff0040,0xefdeffff0050) allocated here: #0 0xaaaad009bcdc (/root/main+0x3bcdc) #1 0xaaaad00b1eb0 (/root/main+0x51eb0) #2 0xaaaad00b20d4 (/root/main+0x520d4) rust-lang#3 0xaaaad00b2800 (/root/main+0x52800) rust-lang#4 0xaaaad00b1cf4 (/root/main+0x51cf4) rust-lang#5 0xaaaad00b33d4 (/root/main+0x533d4) rust-lang#6 0xaaaad00b39b4 (/root/main+0x539b4) rust-lang#7 0xaaaad00b61dc (/root/main+0x561dc) rust-lang#8 0xaaaad00b3578 (/root/main+0x53578) rust-lang#9 0xaaaad0096310 (/root/main+0x36310) Thread: T0 0xeffe00002000 stack: [0xffffc0590000,0xffffc0d90000) sz: 8388608 tls: [0xffff81521020,0xffff815217d0) Memory tags around the buggy address (one tag corresponds to 16 bytes): 0xfefcefffef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefcefffef90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefcefffefa0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefcefffefb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefcefffefc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefcefffefd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefcefffefe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefcefffeff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 =>0xfefceffff000: a2 a2 05 00 e5 [00] 00 00 00 00 00 00 00 00 00 00 0xfefceffff010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefceffff020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefceffff030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefceffff040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefceffff050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefceffff060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefceffff070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xfefceffff080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Tags for short granules around the buggy address (one tag corresponds to 16 bytes): 0xfefcefffeff0: .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. =>0xfefceffff000: .. .. c5 .. .. [..] .. .. .. .. .. .. .. .. .. .. 0xfefceffff010: .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. See https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html#short-granules for a description of short granule tags Registers where the failure occurred (pc 0xaaaad00b3468): x0 e500efdeffff0050 x1 0000000000000004 x2 0000ffffc0d8f5a0 x3 0200efff00000000 x4 0000ffffc0d8f4c0 x5 000000000000004f x6 00000ffffc0d8f36 x7 0000efff00000000 x8 e500efdeffff0050 x9 0200efff00000000 x10 0000000000000000 x11 0200efff00000000 x12 0200effe000006b0 x13 0200effe000006b0 x14 0000000000000008 x15 00000000c00000cf x16 0000aaaad00a0afc x17 0000000000000003 x18 0000000000000001 x19 0000ffffc0d8f718 x20 ba00ffffc0d8f7a0 x21 0000aaaad00962e0 x22 0000000000000000 x23 0000000000000000 x24 0000000000000000 x25 0000000000000000 x26 0000000000000000 x27 0000000000000000 x28 0000000000000000 x29 0000ffffc0d8f650 x30 0000aaaad00b3468 ``` # Comments/Caveats * HWASan is only supported on arm64. * I'm not sure if I should add a feature gate or piggyback on the existing one for sanitizers. * HWASan requires `-C target-feature=+tagged-globals`. That flag should probably be set transparently to the user. Not sure how to go about that. # TODO * Need more tests. * Update documentation. * Fix symbolization. * Integrate with CI

bypass auto_da_alloc for metadata files This saves about 0.7% when rerunning the UI test suite. I.e. when the metadata files exist and will be overwritten. No improvements expected for a clean build. So it might show up in incr-patched perf results. ``` regular rename: Benchmark #1: touch src/tools/compiletest/src/main.rs ; RUSTC_WRAPPER="" schedtool -B -e ./x.py test src/test/ui Time (mean ± σ): 47.305 s ± 0.170 s [User: 1631.540 s, System: 412.648 s] Range (min … max): 47.125 s … 47.856 s 20 runs non-durable rename: Benchmark #1: touch src/tools/compiletest/src/main.rs ; RUSTC_WRAPPER="" schedtool -B -e ./x.py test src/test/ui Time (mean ± σ): 46.930 s ± 0.064 s [User: 1634.344 s, System: 396.038 s] Range (min … max): 46.759 s … 47.043 s 20 runs ``` There are more places that trigger auto_da_alloc behavior by overwriting existing files with O_TRUNC, but those are much harder to locate because `O_TRUNC` is set on `open()` but the writeback is triggered on `close()`. The latter is the part which shows up in profiles.

…nt, r=Mark-Simulacrum Show nicer error when an 'unstable fingerprints' error occurs An example of the error produced by this PR: ``` error: internal compiler error: encountered incremental compilation error with evaluate_obligation(9f2ad55260c30262-c36667639674ad83) | = help: This is a known issue with the compiler. Run `cargo clean -p syn` or `cargo clean` to allow your project to compile = note: Please follow the instructions below to create a bug report with the provided information thread 'rustc' panicked at 'Found unstable fingerprints for evaluate_obligation(9f2ad55260c30262-c36667639674ad83): Ok(EvaluatedToOk)', /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:595:9 stack backtrace: 0: rust_begin_unwind at /home/aaron/repos/rust/library/std/src/panicking.rs:493:5 1: std::panicking::begin_panic_fmt at /home/aaron/repos/rust/library/std/src/panicking.rs:435:5 2: rustc_query_system::query::plumbing::incremental_verify_ich at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:595:9 3: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:557:9 4: rustc_query_system::query::plumbing::try_execute_query::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:473:21 5: core::option::Option<T>::map at /home/aaron/repos/rust/library/core/src/option.rs:487:29 6: rustc_query_system::query::plumbing::try_execute_query::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:471:13 7: stacker::maybe_grow at /home/aaron/.cargo/registry/src/github.com-1ecc6299db9ec823/stacker-0.1.12/src/lib.rs:55:9 8: rustc_data_structures::stack::ensure_sufficient_stack at /home/aaron/repos/rust/compiler/rustc_data_structures/src/stack.rs:16:5 9: <rustc_query_impl::plumbing::QueryCtxt as rustc_query_system::query::QueryContext>::start_query::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_impl/src/plumbing.rs:169:17 10: rustc_middle::ty::context::tls::enter_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1736:50 11: rustc_middle::ty::context::tls::set_tlv at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1720:9 12: rustc_middle::ty::context::tls::enter_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1736:9 13: <rustc_query_impl::plumbing::QueryCtxt as rustc_query_system::query::QueryContext>::start_query::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_impl/src/plumbing.rs:168:13 14: rustc_middle::ty::context::tls::with_related_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1780:13 15: rustc_middle::ty::context::tls::with_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1764:40 16: rustc_middle::ty::context::tls::with_context_opt at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1753:22 17: rustc_middle::ty::context::tls::with_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1764:9 18: rustc_middle::ty::context::tls::with_related_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1777:9 19: <rustc_query_impl::plumbing::QueryCtxt as rustc_query_system::query::QueryContext>::start_query at /home/aaron/repos/rust/compiler/rustc_query_impl/src/plumbing.rs:157:9 20: rustc_query_system::query::plumbing::try_execute_query at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:469:22 21: rustc_query_system::query::plumbing::get_query_impl at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:674:5 22: rustc_query_system::query::plumbing::get_query at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:785:9 23: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::evaluate_obligation at /home/aaron/repos/rust/compiler/rustc_query_impl/src/plumbing.rs:603:17 24: rustc_middle::ty::query::TyCtxtAt::evaluate_obligation at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/query/mod.rs:204:17 25: rustc_middle::ty::query::<impl rustc_middle::ty::context::TyCtxt>::evaluate_obligation at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/query/mod.rs:185:17 26: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::evaluate_obligation at /home/aaron/repos/rust/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs:72:9 27: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::evaluate_obligation_no_overflow at /home/aaron/repos/rust/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs:82:15 28: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::predicate_must_hold_modulo_regions at /home/aaron/repos/rust/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs:58:9 29: rustc_trait_selection::traits::type_known_to_meet_bound_modulo_regions at /home/aaron/repos/rust/compiler/rustc_trait_selection/src/traits/mod.rs:146:18 30: rustc_ty_utils::common_traits::is_item_raw::{{closure}} at /home/aaron/repos/rust/compiler/rustc_ty_utils/src/common_traits.rs:33:9 31: rustc_infer::infer::InferCtxtBuilder::enter at /home/aaron/repos/rust/compiler/rustc_infer/src/infer/mod.rs:582:9 32: rustc_ty_utils::common_traits::is_item_raw at /home/aaron/repos/rust/compiler/rustc_ty_utils/src/common_traits.rs:32:5 33: rustc_query_system::query::config::QueryVtable<CTX,K,V>::compute at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/config.rs:44:9 34: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:544:67 35: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/dep_graph/mod.rs:77:46 36: rustc_middle::ty::context::tls::enter_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1736:50 37: rustc_middle::ty::context::tls::set_tlv at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1720:9 38: rustc_middle::ty::context::tls::enter_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1736:9 39: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/dep_graph/mod.rs:77:13 40: rustc_middle::ty::context::tls::with_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1764:40 41: rustc_middle::ty::context::tls::with_context_opt at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1753:22 42: rustc_middle::ty::context::tls::with_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1764:9 43: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps at /home/aaron/repos/rust/compiler/rustc_middle/src/dep_graph/mod.rs:74:9 44: rustc_query_system::dep_graph::graph::DepGraph<K>::with_ignore at /home/aaron/repos/rust/compiler/rustc_query_system/src/dep_graph/graph.rs:167:9 45: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:544:22 46: rustc_query_system::query::plumbing::try_execute_query::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:473:21 47: core::option::Option<T>::map at /home/aaron/repos/rust/library/core/src/option.rs:487:29 48: rustc_query_system::query::plumbing::try_execute_query::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:471:13 49: stacker::maybe_grow at /home/aaron/.cargo/registry/src/github.com-1ecc6299db9ec823/stacker-0.1.12/src/lib.rs:55:9 50: rustc_data_structures::stack::ensure_sufficient_stack at /home/aaron/repos/rust/compiler/rustc_data_structures/src/stack.rs:16:5 51: <rustc_query_impl::plumbing::QueryCtxt as rustc_query_system::query::QueryContext>::start_query::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_impl/src/plumbing.rs:169:17 52: rustc_middle::ty::context::tls::enter_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1736:50 53: rustc_middle::ty::context::tls::set_tlv at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1720:9 54: rustc_middle::ty::context::tls::enter_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1736:9 55: <rustc_query_impl::plumbing::QueryCtxt as rustc_query_system::query::QueryContext>::start_query::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_impl/src/plumbing.rs:168:13 56: rustc_middle::ty::context::tls::with_related_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1780:13 57: rustc_middle::ty::context::tls::with_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1764:40 58: rustc_middle::ty::context::tls::with_context_opt at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1753:22 59: rustc_middle::ty::context::tls::with_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1764:9 60: rustc_middle::ty::context::tls::with_related_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1777:9 61: <rustc_query_impl::plumbing::QueryCtxt as rustc_query_system::query::QueryContext>::start_query at /home/aaron/repos/rust/compiler/rustc_query_impl/src/plumbing.rs:157:9 62: rustc_query_system::query::plumbing::try_execute_query at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:469:22 63: rustc_query_system::query::plumbing::get_query_impl at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:674:5 64: rustc_query_system::query::plumbing::get_query at /home/aaron/repos/rust/compiler/rustc_query_system/src/query/plumbing.rs:785:9 65: rustc_middle::ty::query::TyCtxtAt::is_unpin_raw at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/query/mod.rs:204:17 66: rustc_middle::ty::util::<impl rustc_middle::ty::TyS>::is_unpin at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/util.rs:727:38 67: rustc_middle::ty::layout::<impl rustc_target::abi::TyAndLayoutMethods<C> for &rustc_middle::ty::TyS>::pointee_info_at at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/layout.rs:2341:32 68: rustc_target::abi::TyAndLayout<Ty>::pointee_info_at at /home/aaron/repos/rust/compiler/rustc_target/src/abi/mod.rs:1164:9 69: <rustc_target::abi::call::FnAbi<&rustc_middle::ty::TyS> as rustc_middle::ty::layout::FnAbiExt<C>>::new_internal::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/layout.rs:2781:36 70: <rustc_target::abi::call::FnAbi<&rustc_middle::ty::TyS> as rustc_middle::ty::layout::FnAbiExt<C>>::new_internal::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/layout.rs:2840:17 71: rustc_target::abi::call::ArgAbi<Ty>::new at /home/aaron/repos/rust/compiler/rustc_target/src/abi/call/mod.rs:457:53 72: <rustc_target::abi::call::FnAbi<&rustc_middle::ty::TyS> as rustc_middle::ty::layout::FnAbiExt<C>>::new_internal::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/layout.rs:2838:27 73: <rustc_target::abi::call::FnAbi<&rustc_middle::ty::TyS> as rustc_middle::ty::layout::FnAbiExt<C>>::new_internal::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/layout.rs:2870:32 74: core::iter::adapters::map::map_fold::{{closure}} at /home/aaron/repos/rust/library/core/src/iter/adapters/map.rs:82:28 75: <core::iter::adapters::enumerate::Enumerate<I> as core::iter::traits::iterator::Iterator>::fold::enumerate::{{closure}} at /home/aaron/repos/rust/library/core/src/iter/adapters/enumerate.rs:104:27 76: core::ops::function::impls::<impl core::ops::function::FnMut<A> for &mut F>::call_mut at /home/aaron/repos/rust/library/core/src/ops/function.rs:269:13 77: core::ops::function::impls::<impl core::ops::function::FnMut<A> for &mut F>::call_mut at /home/aaron/repos/rust/library/core/src/ops/function.rs:269:13 78: core::iter::adapters::map::map_fold::{{closure}} at /home/aaron/repos/rust/library/core/src/iter/adapters/map.rs:82:21 79: core::iter::traits::iterator::Iterator::fold at /home/aaron/repos/rust/library/core/src/iter/traits/iterator.rs:2146:21 80: <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold at /home/aaron/repos/rust/library/core/src/iter/adapters/map.rs:122:9 81: <core::iter::adapters::cloned::Cloned<I> as core::iter::traits::iterator::Iterator>::fold at /home/aaron/repos/rust/library/core/src/iter/adapters/cloned.rs:58:9 82: <core::iter::adapters::chain::Chain<A,B> as core::iter::traits::iterator::Iterator>::fold at /home/aaron/repos/rust/library/core/src/iter/adapters/chain.rs:119:19 83: <core::iter::adapters::chain::Chain<A,B> as core::iter::traits::iterator::Iterator>::fold at /home/aaron/repos/rust/library/core/src/iter/adapters/chain.rs:119:19 84: <core::iter::adapters::enumerate::Enumerate<I> as core::iter::traits::iterator::Iterator>::fold at /home/aaron/repos/rust/library/core/src/iter/adapters/enumerate.rs:110:9 85: <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold at /home/aaron/repos/rust/library/core/src/iter/adapters/map.rs:122:9 86: core::iter::traits::iterator::Iterator::for_each at /home/aaron/repos/rust/library/core/src/iter/traits/iterator.rs:776:9 87: <alloc::vec::Vec<T,A> as alloc::vec::spec_extend::SpecExtend<T,I>>::spec_extend at /home/aaron/repos/rust/library/alloc/src/vec/spec_extend.rs:40:17 88: <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter at /home/aaron/repos/rust/library/alloc/src/vec/spec_from_iter_nested.rs:56:9 89: <alloc::vec::Vec<T> as alloc::vec::spec_from_iter::SpecFromIter<T,I>>::from_iter at /home/aaron/repos/rust/library/alloc/src/vec/spec_from_iter.rs:36:9 90: <alloc::vec::Vec<T> as core::iter::traits::collect::FromIterator<T>>::from_iter at /home/aaron/repos/rust/library/alloc/src/vec/mod.rs:2448:9 91: core::iter::traits::iterator::Iterator::collect at /home/aaron/repos/rust/library/core/src/iter/traits/iterator.rs:1788:9 92: <rustc_target::abi::call::FnAbi<&rustc_middle::ty::TyS> as rustc_middle::ty::layout::FnAbiExt<C>>::new_internal at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/layout.rs:2864:19 93: <rustc_target::abi::call::FnAbi<&rustc_middle::ty::TyS> as rustc_middle::ty::layout::FnAbiExt<C>>::of_instance at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/layout.rs:2670:9 94: rustc_codegen_llvm::mono_item::<impl rustc_codegen_ssa::traits::declare::PreDefineMethods for rustc_codegen_llvm::context::CodegenCx>::predefine_fn at /home/aaron/repos/rust/compiler/rustc_codegen_llvm/src/mono_item.rs:57:22 95: <rustc_middle::mir::mono::MonoItem as rustc_codegen_ssa::mono_item::MonoItemExt>::predefine at /home/aaron/repos/rust/compiler/rustc_codegen_ssa/src/mono_item.rs:76:17 96: rustc_codegen_llvm::base::compile_codegen_unit::module_codegen at /home/aaron/repos/rust/compiler/rustc_codegen_llvm/src/base.rs:122:17 97: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::{{closure}} at /home/aaron/repos/rust/compiler/rustc_query_system/src/dep_graph/graph.rs:235:62 98: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::{{closure}}::{{closure}} at 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/home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1764:9 106: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps at /home/aaron/repos/rust/compiler/rustc_middle/src/dep_graph/mod.rs:74:9 107: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl at /home/aaron/repos/rust/compiler/rustc_query_system/src/dep_graph/graph.rs:235:26 108: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task at /home/aaron/repos/rust/compiler/rustc_query_system/src/dep_graph/graph.rs:205:9 109: rustc_codegen_llvm::base::compile_codegen_unit at /home/aaron/repos/rust/compiler/rustc_codegen_llvm/src/base.rs:103:9 110: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::ExtraBackendMethods>::compile_codegen_unit at /home/aaron/repos/rust/compiler/rustc_codegen_llvm/src/lib.rs:109:9 111: rustc_codegen_ssa::base::codegen_crate at /home/aaron/repos/rust/compiler/rustc_codegen_ssa/src/base.rs:655:38 112: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate at /home/aaron/repos/rust/compiler/rustc_codegen_llvm/src/lib.rs:270:18 113: rustc_interface::passes::start_codegen::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/passes.rs:1021:9 114: rustc_data_structures::profiling::VerboseTimingGuard::run at /home/aaron/repos/rust/compiler/rustc_data_structures/src/profiling.rs:573:9 115: rustc_session::utils::<impl rustc_session::session::Session>::time at /home/aaron/repos/rust/compiler/rustc_session/src/utils.rs:16:9 116: rustc_interface::passes::start_codegen at /home/aaron/repos/rust/compiler/rustc_interface/src/passes.rs:1020:19 117: rustc_interface::queries::Queries::ongoing_codegen::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/queries.rs:296:20 118: rustc_interface::passes::QueryContext::enter::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/passes.rs:755:42 119: rustc_middle::ty::context::tls::enter_context::{{closure}} at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1736:50 120: rustc_middle::ty::context::tls::set_tlv at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1720:9 121: rustc_middle::ty::context::tls::enter_context at /home/aaron/repos/rust/compiler/rustc_middle/src/ty/context.rs:1736:9 122: rustc_interface::passes::QueryContext::enter at /home/aaron/repos/rust/compiler/rustc_interface/src/passes.rs:755:9 123: rustc_interface::queries::Queries::ongoing_codegen::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/queries.rs:287:13 124: rustc_interface::queries::Query<T>::compute at /home/aaron/repos/rust/compiler/rustc_interface/src/queries.rs:40:28 125: rustc_interface::queries::Queries::ongoing_codegen at /home/aaron/repos/rust/compiler/rustc_interface/src/queries.rs:285:9 126: rustc_driver::run_compiler::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_driver/src/lib.rs:442:13 127: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter at /home/aaron/repos/rust/compiler/rustc_interface/src/queries.rs:428:19 128: rustc_driver::run_compiler::{{closure}} at /home/aaron/repos/rust/compiler/rustc_driver/src/lib.rs:337:22 129: rustc_interface::interface::create_compiler_and_run::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/interface.rs:208:13 130: rustc_span::with_source_map at /home/aaron/repos/rust/compiler/rustc_span/src/lib.rs:788:5 131: rustc_interface::interface::create_compiler_and_run at /home/aaron/repos/rust/compiler/rustc_interface/src/interface.rs:202:5 132: rustc_interface::interface::run_compiler::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/interface.rs:224:12 133: rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals::{{closure}}::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/util.rs:155:13 134: scoped_tls::ScopedKey<T>::set at /home/aaron/.cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-1.0.0/src/lib.rs:137:9 135: rustc_span::with_session_globals at /home/aaron/repos/rust/compiler/rustc_span/src/lib.rs:105:5 136: rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/util.rs:153:9 137: rustc_interface::util::scoped_thread::{{closure}} at /home/aaron/repos/rust/compiler/rustc_interface/src/util.rs:128:24 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/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md note: rustc 1.54.0-dev running on x86_64-unknown-linux-gnu note: compiler flags: -C opt-level=3 -C embed-bitcode=no -C incremental --crate-type lib note: some of the compiler flags provided by cargo are hidden query stack during panic: #0 [evaluate_obligation] evaluating trait selection obligation `quote::Tokens: std::marker::Unpin` #1 [is_unpin_raw] computing whether `quote::Tokens` is `Unpin` end of query stack error: aborting due to previous error error: could not compile `syn` To learn more, run the command again with --verbose. ``` I've left in the panic and ICE following the pretty error, so that we still have all of the debug information available in a bug report. This message can be reproduced by cloning the repository `https://github.com/Aaron1011/syn-crash`, and running the following shell script (with a `rustup override` set in the directory): ``` set -xe cargo clean -p syn cargo clean --release -p syn git checkout minimize cargo build --release -j 1 git checkout minimize-change cargo build --release -j 1 ``` r? ``@Mark-Simulacrum``

Otherwise, we can get into a situation where you have a subtype obligation `#1 <: #2` pending, #1 is constrained by `check_casts`, but #2` is unaffected. Co-authored-by: Niko Matsakis <niko@alum.mit.edu>

…u-se Implement `SpecOptionPartialEq` for `cmp::Ordering` Noticed as I continue to explore options for having code using `partial_cmp` optimize better. Before: ```llvm ; Function Attrs: mustprogress nofree nosync nounwind willreturn uwtable define noundef zeroext i1 `@ordering_eq(i8` noundef %0, i8 noundef %1) unnamed_addr #0 { start: %2 = icmp eq i8 %0, 2 br i1 %2, label %bb1.i, label %bb3.i bb1.i: ; preds = %start %3 = icmp eq i8 %1, 2 br label %"_ZN55_$LT$T$u20$as$u20$core..option..SpecOptionPartialEq$GT$2eq17hb7e7beacecde585fE.exit" bb3.i: ; preds = %start %.not.i = icmp ne i8 %1, 2 %4 = icmp eq i8 %0, %1 %spec.select.i = and i1 %.not.i, %4 br label %"_ZN55_$LT$T$u20$as$u20$core..option..SpecOptionPartialEq$GT$2eq17hb7e7beacecde585fE.exit" "_ZN55_$LT$T$u20$as$u20$core..option..SpecOptionPartialEq$GT$2eq17hb7e7beacecde585fE.exit": ; preds = %bb1.i, %bb3.i %.0.i = phi i1 [ %3, %bb1.i ], [ %spec.select.i, %bb3.i ] ret i1 %.0.i } ``` After: ```llvm ; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn uwtable define noundef zeroext i1 `@ordering_eq(i8` noundef %0, i8 noundef %1) unnamed_addr #1 { start: %2 = icmp eq i8 %0, %1 ret i1 %2 } ``` (Which <https://alive2.llvm.org/ce/z/-rop5r> says LLVM *could* just do itself, but there's probably an issue already open for that problem from when this was originally looked at for `Option<NonZeroU8>` and friends.)

Fix SGX RWLock representation for UnsafeCell niche fix

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jethrogb mentioned this pull request Jan 31, 2020

Hide niches under UnsafeCell rust-lang/rust#68491

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jethrogb requested a review from pnkfelix January 31, 2020 14:22

Pagten approved these changes Jan 31, 2020

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eddyb reviewed Jan 31, 2020

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pnkfelix merged this pull request into pnkfelix:hide-niches-under-unsafe-cell Feb 3, 2020

jethrogb mentioned this pull request Feb 10, 2020

Reduce uninitialized memory trickery in RWLock C interface test fortanix/rust-sgx#213

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jethrogb mentioned this pull request Sep 3, 2020

Improve SGX RWLock initializer test rust-lang/rust#76278

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Fix SGX RWLock representation for UnsafeCell niche fix #1

Fix SGX RWLock representation for UnsafeCell niche fix #1

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Fix SGX RWLock representation for UnsafeCell niche fix #1

Fix SGX RWLock representation for UnsafeCell niche fix #1

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