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Miri backtrace improvements #55970

Merged
merged 4 commits into from
Nov 19, 2018
Merged

Miri backtrace improvements #55970

merged 4 commits into from
Nov 19, 2018

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RalfJung
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Nicer pretty-printing of the RUST_CTFE_BACKTRACE-backtraces:

  0: backtrace::backtrace::libunwind::trace::hc410fcb66fe85b11
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/libunwind.rs:53
     backtrace::backtrace::trace::h2106294a22648407
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/mod.rs:42
  1: backtrace::capture::Backtrace::new_unresolved::h5d8d98b993d092ba
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:88
  2: <rustc::mir::interpret::error::EvalError<'tcx> as core::convert::From<rustc::mir::interpret::error::EvalErrorKind<'tcx, u64>>>::from::h6355269b2a661412
           at librustc/mir/interpret/error.rs:236
  3: <T as core::convert::Into<U>>::into::h70fcb917509539bd
           at /home/r/src/rust/rustc.2/src/libcore/convert.rs:455
  4: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::emulate_foreign_item::h9cde0e3ce7455a4a
           at src/fn_call.rs:292
  5: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::find_fn::h83f89524b9d1a49a
           at src/fn_call.rs:74
  6: <miri::Evaluator<'tcx> as rustc_mir::interpret::machine::Machine<'a, 'mir, 'tcx>>::find_fn::hf9980473c4775f0c
           at src/lib.rs:345
     rustc_mir::interpret::terminator::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::eval_fn_call::h401dec4a687f96e9
           at /home/r/src/rust/rustc.2/src/librustc_mir/interpret/terminator.rs:285

Indentation is now consistent with RUST_BACKTRACE, and the frame number is not repeated when there are multiple symbols for a frame.

Also preserve the ty::Instance for the internal backtrace (showing which frames in the user code where on the interpreter stack when the error happened), used by miri to avoid printing spans for libstd internals:

error[E0080]: constant evaluation error: the evaluated program panicked
   --> /home/r/src/rust/rustc.2/src/libstd/panicking.rs:525:9
    |
525 |         __rust_start_panic(obj as usize)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked
    |
    = note: inside call to `std::panicking::rust_panic` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:496:5
    = note: inside call to `std::panicking::rust_panic_with_hook` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:390:5
    = note: inside call to `std::panicking::continue_panic_fmt` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:345:5
note: inside call to `std::rt::begin_panic_fmt` at <::std::macros::panic macros>:8:1
   --> tests/compile-fail/panic.rs:4:5
    |
4   |     assert_eq!(5, 6);
    |     ^^^^^^^^^^^^^^^^^
    = note: inside call to `main` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:74:34
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/rt.rs:59:75
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/sys_common/backtrace.rs:136:5
    = note: inside call to `std::sys_common::backtrace::__rust_begin_short_backtrace::<[closure@DefId(1/1:1913 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]::{{closure}}[0]) 0:&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:59:13
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:310:40
    = note: inside call to `std::panicking::try::do_call::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:306:5
    = note: inside call to `std::panicking::try::<i32, [closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe]>` at /home/r/src/rust/rustc.2/src/libstd/panic.rs:398:9
    = note: inside call to `std::panic::catch_unwind::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:58:25
    = note: inside call to `std::rt::lang_start_internal` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:74:5
    = note: inside call to `std::rt::lang_start::<()>`

Also notice that we show filenames and line numbers here now.

r? @oli-obk

@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Nov 15, 2018
@RalfJung
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Cc @shepmaster you suggested miri's backtraces could be improved, would be interested in your feedback!

@RalfJung
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Matching miri PR: rust-lang/miri#523

@oli-obk
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oli-obk commented Nov 15, 2018

r=me with @shepmaster feedback

@shepmaster
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The two examples look good to me; would it be trivial to post here what they used to look like for comparison purposes?

@RalfJung
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Sure. The first one just got some repeated numbers:

0: backtrace::backtrace::libunwind::trace::hc410fcb66fe85b11
         at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/libunwind.rs:53
0: backtrace::backtrace::trace::h2106294a22648407
         at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/mod.rs:42
1: backtrace::capture::Backtrace::new_unresolved::h5d8d98b993d092ba
         at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:88
2: <rustc::mir::interpret::error::EvalError<'tcx> as core::convert::From<rustc::mir::interpret::error::EvalErrorKind<'tcx, u64>>>::from::h6355269b2a661412
         at librustc/mir/interpret/error.rs:236
3: <T as core::convert::Into<U>>::into::h70fcb917509539bd
         at /home/r/src/rust/rustc.2/src/libcore/convert.rs:455
4: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::emulate_foreign_item::h9cde0e3ce7455a4a
         at src/fn_call.rs:292
5: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::find_fn::h83f89524b9d1a49a
         at src/fn_call.rs:74
6: <miri::Evaluator<'tcx> as rustc_mir::interpret::machine::Machine<'a, 'mir, 'tcx>>::find_fn::hf9980473c4775f0c
         at src/lib.rs:345
6: rustc_mir::interpret::terminator::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::eval_fn_call::h401dec4a687f96e9
         at /home/r/src/rust/rustc.2/src/librustc_mir/interpret/terminator.rs:285

The second, uh...

error[E0080]: constant evaluation error: the evaluated program panicked
   --> /home/r/src/rust/rustc/src/libstd/panicking.rs:525:9
    |
525 |         __rust_start_panic(obj as usize)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked
    |
note: inside call to `std::panicking::rust_panic`
   --> /home/r/src/rust/rustc/src/libstd/panicking.rs:496:5
    |
496 |     rust_panic(payload)
    |     ^^^^^^^^^^^^^^^^^^^
note: inside call to `std::panicking::rust_panic_with_hook`
   --> /home/r/src/rust/rustc/src/libstd/panicking.rs:390:5
    |
390 | /     rust_panic_with_hook(
391 | |         &mut PanicPayload::new(msg),
392 | |         info.message(),
393 | |         &file_line_col);
    | |_______________________^
note: inside call to `std::panicking::continue_panic_fmt`
   --> /home/r/src/rust/rustc/src/libstd/panicking.rs:345:5
    |
345 |     continue_panic_fmt(&info)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^
note: inside call to `std::rt::begin_panic_fmt`
   --> tests/compile-fail/panic.rs:4:5
    |
4   |     assert_eq!(5, 6);
    |     ^^^^^^^^^^^^^^^^^
note: inside call to `main`
   --> /home/r/src/rust/rustc/src/libstd/rt.rs:74:34
    |
74  |     lang_start_internal(&move || main().report(), argc, argv)
    |                                  ^^^^^^
note: inside call to `closure`
   --> /home/r/src/rust/rustc/src/libstd/rt.rs:59:75
    |
59  |             ::sys_common::backtrace::__rust_begin_short_backtrace(move || main())
    |                                                                           ^^^^^^
note: inside call to `closure`
   --> /home/r/src/rust/rustc/src/libstd/sys_common/backtrace.rs:136:5
    |
136 |     f()
    |     ^^^
note: inside call to `std::sys_common::backtrace::__rust_begin_short_backtrace::<[closure@DefId(1/1:1913 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]::{{closure}}[0]) 0:&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>`
   --> /home/r/src/rust/rustc/src/libstd/rt.rs:59:13
    |
59  |             ::sys_common::backtrace::__rust_begin_short_backtrace(move || main())
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: inside call to `closure`
   --> /home/r/src/rust/rustc/src/libstd/panicking.rs:310:40
    |
310 |             ptr::write(&mut (*data).r, f());
    |                                        ^^^
note: inside call to `std::panicking::try::do_call::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>`
   --> /home/r/src/rust/rustc/src/libstd/panicking.rs:306:5
    |
306 | /     fn do_call<F: FnOnce() -> R, R>(data: *mut u8) {
307 | |         unsafe {
308 | |             let data = data as *mut Data<F, R>;
309 | |             let f = ptr::read(&mut (*data).f);
310 | |             ptr::write(&mut (*data).r, f());
311 | |         }
312 | |     }
    | |_____^
note: inside call to `std::panicking::try::<i32, [closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe]>`
   --> /home/r/src/rust/rustc/src/libstd/panic.rs:398:9
    |
398 |         panicking::try(f)
    |         ^^^^^^^^^^^^^^^^^
note: inside call to `std::panic::catch_unwind::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>`
   --> /home/r/src/rust/rustc/src/libstd/rt.rs:58:25
    |
58  |           let exit_code = panic::catch_unwind(|| {
    |  _________________________^
59  | |             ::sys_common::backtrace::__rust_begin_short_backtrace(move || main())
60  | |         });
    | |__________^
note: inside call to `std::rt::lang_start_internal`
   --> /home/r/src/rust/rustc/src/libstd/rt.rs:74:5
    |
74  |     lang_start_internal(&move || main().report(), argc, argv)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

@shepmaster
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@bors r=@oli-obk

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bors commented Nov 15, 2018

📌 Commit 62cf9ab has been approved by @oli-obk

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Nov 15, 2018
pietroalbini added a commit to pietroalbini/rust that referenced this pull request Nov 18, 2018
Miri backtrace improvements

Nicer pretty-printing of the `RUST_CTFE_BACKTRACE`-backtraces:
```
  0: backtrace::backtrace::libunwind::trace::hc410fcb66fe85b11
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/libunwind.rs:53
     backtrace::backtrace::trace::h2106294a22648407
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/mod.rs:42
  1: backtrace::capture::Backtrace::new_unresolved::h5d8d98b993d092ba
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:88
  2: <rustc::mir::interpret::error::EvalError<'tcx> as core::convert::From<rustc::mir::interpret::error::EvalErrorKind<'tcx, u64>>>::from::h6355269b2a661412
           at librustc/mir/interpret/error.rs:236
  3: <T as core::convert::Into<U>>::into::h70fcb917509539bd
           at /home/r/src/rust/rustc.2/src/libcore/convert.rs:455
  4: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::emulate_foreign_item::h9cde0e3ce7455a4a
           at src/fn_call.rs:292
  5: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::find_fn::h83f89524b9d1a49a
           at src/fn_call.rs:74
  6: <miri::Evaluator<'tcx> as rustc_mir::interpret::machine::Machine<'a, 'mir, 'tcx>>::find_fn::hf9980473c4775f0c
           at src/lib.rs:345
     rustc_mir::interpret::terminator::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::eval_fn_call::h401dec4a687f96e9
           at /home/r/src/rust/rustc.2/src/librustc_mir/interpret/terminator.rs:285
```
Indentation is now consistent with `RUST_BACKTRACE`, and the frame number is not repeated when there are multiple symbols for a frame.

Also preserve the `ty::Instance` for the internal backtrace (showing which frames in the user code where on the interpreter stack when the error happened), used by miri to avoid printing spans for libstd internals:
```
error[E0080]: constant evaluation error: the evaluated program panicked
   --> /home/r/src/rust/rustc.2/src/libstd/panicking.rs:525:9
    |
525 |         __rust_start_panic(obj as usize)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked
    |
    = note: inside call to `std::panicking::rust_panic` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:496:5
    = note: inside call to `std::panicking::rust_panic_with_hook` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:390:5
    = note: inside call to `std::panicking::continue_panic_fmt` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:345:5
note: inside call to `std::rt::begin_panic_fmt` at <::std::macros::panic macros>:8:1
   --> tests/compile-fail/panic.rs:4:5
    |
4   |     assert_eq!(5, 6);
    |     ^^^^^^^^^^^^^^^^^
    = note: inside call to `main` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:74:34
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/rt.rs:59:75
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/sys_common/backtrace.rs:136:5
    = note: inside call to `std::sys_common::backtrace::__rust_begin_short_backtrace::<[closure@DefId(1/1:1913 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]::{{closure}}[0]) 0:&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:59:13
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:310:40
    = note: inside call to `std::panicking::try::do_call::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:306:5
    = note: inside call to `std::panicking::try::<i32, [closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe]>` at /home/r/src/rust/rustc.2/src/libstd/panic.rs:398:9
    = note: inside call to `std::panic::catch_unwind::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:58:25
    = note: inside call to `std::rt::lang_start_internal` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:74:5
    = note: inside call to `std::rt::lang_start::<()>`
```
Also notice that we show filenames and line numbers here now.

r? @oli-obk
bors added a commit that referenced this pull request Nov 19, 2018
Rollup of 25 pull requests

Successful merges:

 - #55562 (Add powerpc- and powerpc64-unknown-linux-musl targets)
 - #55564 (test/linkage-visibility: Ignore on musl targets)
 - #55827 (A few tweaks to iterations/collecting)
 - #55834 (Forward the ABI of the non-zero sized fields of an union if they have the same ABI)
 - #55857 (remove unused dependency)
 - #55862 (in which the E0618 "expected function" diagnostic gets a makeover)
 - #55867 (do not panic just because cargo failed)
 - #55894 (miri enum discriminant handling: Fix treatment of pointers, better error when it is undef)
 - #55916 (Make miri value visitor usfeful for mutation)
 - #55919 (core/tests/num: Simplify `test_int_from_str_overflow()` test code)
 - #55923 (reword #[test] attribute error on fn items)
 - #55935 (appveyor: Use VS2017 for all our images)
 - #55949 (ty: return impl Iterator from Predicate::walk_tys)
 - #55952 (Update to Clang 7 on CI.)
 - #55953 (#53488 Refactoring UpvarId)
 - #55962 (rustdoc: properly calculate spans for intra-doc link resolution errors)
 - #55963 (Stress test for MPSC)
 - #55968 (Clean up some non-mod-rs stuff.)
 - #55970 (Miri backtrace improvements)
 - #56007 (CTFE: dynamically make sure we do not call non-const-fn)
 - #56011 (Replace data.clone() by Arc::clone(&data) in mutex doc.)
 - #56012 (avoid shared ref in UnsafeCell::get)
 - #56016 (Add VecDeque::resize_with)
 - #56027 (docs: Add missing backtick in object_safety.rs docs)
 - #56043 (remove "approx env bounds" if we already know from trait)

Failed merges:

r? @ghost
kennytm pushed a commit to pietroalbini/rust that referenced this pull request Nov 19, 2018
Miri backtrace improvements

Nicer pretty-printing of the `RUST_CTFE_BACKTRACE`-backtraces:
```
  0: backtrace::backtrace::libunwind::trace::hc410fcb66fe85b11
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/libunwind.rs:53
     backtrace::backtrace::trace::h2106294a22648407
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/mod.rs:42
  1: backtrace::capture::Backtrace::new_unresolved::h5d8d98b993d092ba
           at /home/r/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:88
  2: <rustc::mir::interpret::error::EvalError<'tcx> as core::convert::From<rustc::mir::interpret::error::EvalErrorKind<'tcx, u64>>>::from::h6355269b2a661412
           at librustc/mir/interpret/error.rs:236
  3: <T as core::convert::Into<U>>::into::h70fcb917509539bd
           at /home/r/src/rust/rustc.2/src/libcore/convert.rs:455
  4: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::emulate_foreign_item::h9cde0e3ce7455a4a
           at src/fn_call.rs:292
  5: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::find_fn::h83f89524b9d1a49a
           at src/fn_call.rs:74
  6: <miri::Evaluator<'tcx> as rustc_mir::interpret::machine::Machine<'a, 'mir, 'tcx>>::find_fn::hf9980473c4775f0c
           at src/lib.rs:345
     rustc_mir::interpret::terminator::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::eval_fn_call::h401dec4a687f96e9
           at /home/r/src/rust/rustc.2/src/librustc_mir/interpret/terminator.rs:285
```
Indentation is now consistent with `RUST_BACKTRACE`, and the frame number is not repeated when there are multiple symbols for a frame.

Also preserve the `ty::Instance` for the internal backtrace (showing which frames in the user code where on the interpreter stack when the error happened), used by miri to avoid printing spans for libstd internals:
```
error[E0080]: constant evaluation error: the evaluated program panicked
   --> /home/r/src/rust/rustc.2/src/libstd/panicking.rs:525:9
    |
525 |         __rust_start_panic(obj as usize)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked
    |
    = note: inside call to `std::panicking::rust_panic` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:496:5
    = note: inside call to `std::panicking::rust_panic_with_hook` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:390:5
    = note: inside call to `std::panicking::continue_panic_fmt` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:345:5
note: inside call to `std::rt::begin_panic_fmt` at <::std::macros::panic macros>:8:1
   --> tests/compile-fail/panic.rs:4:5
    |
4   |     assert_eq!(5, 6);
    |     ^^^^^^^^^^^^^^^^^
    = note: inside call to `main` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:74:34
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/rt.rs:59:75
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/sys_common/backtrace.rs:136:5
    = note: inside call to `std::sys_common::backtrace::__rust_begin_short_backtrace::<[closure@DefId(1/1:1913 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]::{{closure}}[0]) 0:&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:59:13
    = note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:310:40
    = note: inside call to `std::panicking::try::do_call::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:306:5
    = note: inside call to `std::panicking::try::<i32, [closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe]>` at /home/r/src/rust/rustc.2/src/libstd/panic.rs:398:9
    = note: inside call to `std::panic::catch_unwind::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:58:25
    = note: inside call to `std::rt::lang_start_internal` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:74:5
    = note: inside call to `std::rt::lang_start::<()>`
```
Also notice that we show filenames and line numbers here now.

r? @oli-obk
bors added a commit that referenced this pull request Nov 19, 2018
Rollup of 25 pull requests

Successful merges:

 - #55562 (Add powerpc- and powerpc64-unknown-linux-musl targets)
 - #55564 (test/linkage-visibility: Ignore on musl targets)
 - #55827 (A few tweaks to iterations/collecting)
 - #55834 (Forward the ABI of the non-zero sized fields of an union if they have the same ABI)
 - #55857 (remove unused dependency)
 - #55862 (in which the E0618 "expected function" diagnostic gets a makeover)
 - #55867 (do not panic just because cargo failed)
 - #55894 (miri enum discriminant handling: Fix treatment of pointers, better error when it is undef)
 - #55916 (Make miri value visitor useful for mutation)
 - #55919 (core/tests/num: Simplify `test_int_from_str_overflow()` test code)
 - #55923 (reword #[test] attribute error on fn items)
 - #55949 (ty: return impl Iterator from Predicate::walk_tys)
 - #55952 (Update to Clang 7 on CI.)
 - #55953 (#53488 Refactoring UpvarId)
 - #55962 (rustdoc: properly calculate spans for intra-doc link resolution errors)
 - #55963 (Stress test for MPSC)
 - #55968 (Clean up some non-mod-rs stuff.)
 - #55970 (Miri backtrace improvements)
 - #56007 (CTFE: dynamically make sure we do not call non-const-fn)
 - #56011 (Replace data.clone() by Arc::clone(&data) in mutex doc.)
 - #56012 (avoid shared ref in UnsafeCell::get)
 - #56016 (Add VecDeque::resize_with)
 - #56027 (docs: Add missing backtick in object_safety.rs docs)
 - #56043 (remove "approx env bounds" if we already know from trait)
 - #56059 (Increase `Duration` approximate equal threshold to 1us)
@bors bors merged commit 62cf9ab into rust-lang:master Nov 19, 2018
@RalfJung RalfJung deleted the miri-backtrace branch November 30, 2018 08:28
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5 participants