Miri: make backtrace function names and spans match up
Currently, Miri backtraces are a bit confusing:
```
error: Undefined Behavior: entering unreachable code
--> tests/compile-fail/never_transmute_void.rs:10:11
|
10 | match v {} //~ ERROR entering unreachable code
| ^ entering unreachable code
|
= help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
= help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
note: inside call to `f` at tests/compile-fail/never_transmute_void.rs:17:5
--> tests/compile-fail/never_transmute_void.rs:17:5
|
17 | f(v); //~ inside call to `f`
| ^^^^
= note: inside call to `main` at /home/r/.rustup/toolchains/miri/lib/rustlib/src/rust/src/libstd/rt.rs:67:34
= note: inside call to closure at /home/r/.rustup/toolchains/miri/lib/rustlib/src/rust/src/libstd/rt.rs:52:73
= note: inside call to closure at /home/r/.rustup/toolchains/miri/lib/rustlib/src/rust/src/libstd/sys_common/backtrace.rs:130:5
```
When reading this like a normal backtrace, one would expect that e.g. the backrace involves the "main" function at "libstd/rt.rs:67:34". But that is not actually where we are in the main function, that is *where the main function is called*.
This is not how backtraces are usually rendered (including e.g. with `RUST_BACKTRACE=1`). Usually we print next to each function name where inside that function the frame is currently executing, not where the *parent* frame is executing. With this PR and the Miri side at https://github.com/rust-lang/miri/pull/1283, the backtrace now looks as follows:
```
error: Undefined Behavior: entering unreachable code
--> tests/compile-fail/never_transmute_void.rs:10:11
|
10 | match v {} //~ ERROR entering unreachable code
| ^ entering unreachable code
|
= help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
= help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
= note: inside `f` at tests/compile-fail/never_transmute_void.rs:10:11
note: inside `main` at tests/compile-fail/never_transmute_void.rs:17:5
--> tests/compile-fail/never_transmute_void.rs:17:5
|
17 | f(v); //~ inside `main`
| ^^^^
= note: inside closure at /home/r/src/rust/rustc/src/libstd/rt.rs:67:34
= note: inside closure at /home/r/src/rust/rustc/src/libstd/rt.rs:52:73
= note: inside `std::sys_common::backtrace::__rust_begin_short_backtrace::<[closure@DefId(1:6034 ~ std[87db]::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/src/libstd/sys_common/backtrace.rs:130:5
```
Now function name and printed line numbers match up in the notes.
This code is partially shared with const-eval, so the change also affects const-eval: instead of printing what is being called at some span, we print which function/constant this span is inside.
With this, we can also remove the `span` field from Miri's stack frames (which used to track the *caller span* of that frame, quite confusing), and then get of a whole lot of `span` arguments that ultimately just served to fill that field (and as a fallback for `caller_location`, which however was never actually used).
r? @oli-obk
Rollup of 6 pull requests
Successful merges:
- #70511 (Add `-Z dump-mir-dataflow` flag for dumping dataflow results visualization)
- #70522 (Improve error messages for raw strings (#60762))
- #70547 (Add `can_unwind` field to `FnAbi`)
- #70591 (Ensure LLVM is in the link path for "fulldeps" tests)
- #70627 (Use place directly its copy)
- #70652 (Add git repo address to unstable book)
Failed merges:
- #70634 (Remove some reexports in `rustc_middle`)
r? @ghost
Ensure LLVM is in the link path for "fulldeps" tests
This is a follow-up to #70123, which added `llvm-config --libdir` to the
`LIBRARY_PATH` for rustc tools. We need the same for "run-make-fulldeps"
and "ui-fulldeps" tests which depend on compiler libraries, implicitly
needing to link to `-lLLVM` as well.
Improve error messages for raw strings (#60762)
This diff improves error messages around raw strings in a few ways:
- Catch extra trailing `#` in the parser. This can't be handled in the lexer because we could be in a macro that actually expects another # (see test)
- Refactor & unify error handling in the lexer between ByteStrings and RawByteStrings
- Detect potentially intended terminators (longest sequence of "#*" is suggested)
Fixes#60762
cc @estebank who reviewed the original (abandoned) PR for the same ticket.
r? @Centril
Add `-Z dump-mir-dataflow` flag for dumping dataflow results visualization
Previously, to visualize the results of a MIR dataflow pass, one had to add a `#[rustc_mir(borrowck_graphviz_postflow)]` attribute to functions of interest. However, there is no way to specify this attribute on closures and generators, so it was impossible to view results for these MIR bodies.
This PR adds a flag, `-Z dump-mir-dataflow`, which will output the dataflow results for any functions specified in `-Z dump-mir` to the output directory specified by `-Z dump-mir-dir`. This behavior is modeled on the `-Z dump-mir-graphviz` flag.
Upgrade GCC to 8.3.0, glibc to 2.17.0 and crosstool-ng to 1.24.0 for dist-arm-linux and dist-armhf-linux
Attempt to fix#69420 in the same manner as #65302 did for armv7l. I have tested that this eliminates the segfault while building a `hello_world` package on `arm-unknown-linux-gnueabihf`.
I have not been able to test whether the bug exists for `arm-unknown-linux-gnueabi` as well, but I suspect it does, so I upgraded the toolchain for that platform as well.
expand vec![] to Vec::new()
The current expansion of `vec![]` calls `into_vec` on a boxed slice, which results in longer IR, and even after optimization, some unwinding artifacts are still present in the IR. This PR uses `Vec::new()` for `vec![]`.
This also allows `vec![]` to be used in const expressions.
add `unused_braces` lint
Add the lint `unused_braces` which is warn by default.
`unused_parens` is also extended and now checks anon consts.
closes#68387
r? @varkor
BTreeMap/BTreeSet: implement drain_filter
Provide an implementation of drain_filter for BTreeMap and BTreeSet. Should be optimal when the predicate picks only elements in leaf nodes with at least MIN_LEN remaining elements, which is a common case, at least when draining only a fraction of the map/set, and also when the predicate picks elements stored in internal nodes where the right subtree can easily let go of a replacement element.
The first commit adds benchmarks with an external, naive implementation. to compare how much this claimed optimality-in-some-cases is actually worth.
Rollup of 7 pull requests
Successful merges:
- #69425 (add fn make_contiguous to VecDeque)
- #69458 (improve folder name for persistent doc tests)
- #70268 (Document ThreadSanitizer in unstable-book)
- #70600 (Ensure there are versions of test code for aarch64 windows)
- #70606 (Clean up E0466 explanation)
- #70614 (remove unnecessary relocation check in const_prop)
- #70623 (Fix broken link in README)
Failed merges:
r? @ghost
While for auto, try and PR builds we only want the latest commit to be
tested, that's not true for try builds: each commit pushed to the branch
is a different PR being tested, and we want multiple PRs to be tested in
parallel if there is enough demand.
Fixes#70569
