Prune backtraces similar to RUST_BACKTRACE=1 logic
This removes the majority of output from `cargo miri run` and `cargo miri test` in common usage.
~~I've copied the logic almost directly from `std`:
3b186511f6/library/std/src/sys_common/backtrace.rs (L76-L77~~)
~~It might be nice to have the "some details were omitted" note and a fallback to a setting where we print everything just in case this logic goes sideways, but~~
~~1. I'm not sure where to put the note~~
~~2. `MIRI_BACKTRACE`, `RUST_BACKTRACE`, and `RUSTC_CTFE_BACKTRACE` already do something else. Should we repurpose or add on to the semantics of `MIRI_BACKTRACE`?~~
---
Based on this tiny silly crate:
```rust
fn main() {
some_function();
}
fn some_function() {
unsafe {
let _x: &u8 = core::mem::transmute(1usize);
}
}
#[cfg(test)]
mod tests {
#[test]
fn it_works() {
unsafe {
let _x: &'static u8 = core::mem::transmute(1usize);
}
}
}
```
`cargo miri run`:
Before:
```
Finished dev [unoptimized + debuginfo] target(s) in 0.10s
Running `/home/ben/.cargo/bin/cargo-miri target/miri/x86_64-unknown-linux-gnu/debug/scratch`
error: Undefined Behavior: type validation failed: encountered a dangling reference (address 0x1 is unallocated)
--> src/main.rs:7:23
|
7 | let _x: &u8 = core::mem::transmute(1usize);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a dangling reference (address 0x1 is unallocated)
|
= 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 `some_function` at src/main.rs:7:23
note: inside `main` at src/main.rs:2:5
--> src/main.rs:2:5
|
2 | some_function();
| ^^^^^^^^^^^^^^^
= note: inside `<fn() as std::ops::FnOnce<()>>::call_once - shim(fn())` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/ops/function.rs:227:5
= note: inside `std::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/sys_common/backtrace.rs:122:18
= note: inside closure at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/rt.rs:145:18
= note: inside `std::ops::function::impls::<impl std::ops::FnOnce<()> for &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>::call_once` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/ops/function.rs:259:13
= note: inside `std::panicking::r#try::do_call::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:492:40
= note: inside `std::panicking::r#try::<i32, &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:456:19
= note: inside `std::panic::catch_unwind::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panic.rs:137:14
= note: inside closure at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/rt.rs:128:48
= note: inside `std::panicking::r#try::do_call::<[closure@std::rt::lang_start_internal::{closure#2}], isize>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:492:40
= note: inside `std::panicking::r#try::<isize, [closure@std::rt::lang_start_internal::{closure#2}]>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:456:19
= note: inside `std::panic::catch_unwind::<[closure@std::rt::lang_start_internal::{closure#2}], isize>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panic.rs:137:14
= note: inside `std::rt::lang_start_internal` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/rt.rs:128:20
= note: inside `std::rt::lang_start::<()>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/rt.rs:144:17
error: aborting due to previous error
```
After:
``` Finished dev [unoptimized + debuginfo] target(s) in 0.10s
Running `/home/ben/.cargo/bin/cargo-miri target/miri/x86_64-unknown-linux-gnu/debug/scratch`
error: Undefined Behavior: type validation failed: encountered a dangling reference (address 0x1 is unallocated)
--> src/main.rs:7:23
|
7 | let _x: &u8 = core::mem::transmute(1usize);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a dangling reference (address 0x1 is unallocated)
|
= 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 `some_function` at src/main.rs:7:23
note: inside `main` at src/main.rs:2:5
--> src/main.rs:2:5
|
2 | some_function();
| ^^^^^^^^^^^^^^^
note: Some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace.
error: aborting due to previous error
```
`cargo miri test`
Before:
```
Finished test [unoptimized + debuginfo] target(s) in 0.00s
Running unittests (target/miri/x86_64-unknown-linux-gnu/debug/deps/scratch-9d7717efc37bb64c)
running 1 test
test tests::it_works ... error: Undefined Behavior: type validation failed: encountered a dangling reference (address 0x1 is unallocated)
--> src/main.rs:16:35
|
16 | let _x: &'static u8 = core::mem::transmute(1usize);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a dangling reference (address 0x1 is unallocated)
|
= 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 `tests::it_works` at src/main.rs:16:35
note: inside closure at src/main.rs:14:5
--> src/main.rs:14:5
|
13 | #[test]
| ------- in this procedural macro expansion
14 | / fn it_works() {
15 | | unsafe {
16 | | let _x: &'static u8 = core::mem::transmute(1usize);
17 | | }
18 | | }
| |_____^
= note: inside `<[closure@src/main.rs:14:5: 18:6] as std::ops::FnOnce<()>>::call_once - shim` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/ops/function.rs:227:5
= note: inside `<fn() as std::ops::FnOnce<()>>::call_once - shim(fn())` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/ops/function.rs:227:5
= note: inside `tests::test::__rust_begin_short_backtrace::<fn()>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:575:5
= note: inside closure at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:566:30
= note: inside `<[closure@tests::test::run_test::{closure#1}] as std::ops::FnOnce<()>>::call_once - shim(vtable)` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/ops/function.rs:227:5
= note: inside `<std::boxed::Box<dyn std::ops::FnOnce() + std::marker::Send> as std::ops::FnOnce<()>>::call_once` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/alloc/src/boxed.rs:1854:9
= note: inside `<std::panic::AssertUnwindSafe<std::boxed::Box<dyn std::ops::FnOnce() + std::marker::Send>> as std::ops::FnOnce<()>>::call_once` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/panic/unwind_safe.rs:271:9
= note: inside `std::panicking::r#try::do_call::<std::panic::AssertUnwindSafe<std::boxed::Box<dyn std::ops::FnOnce() + std::marker::Send>>, ()>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:492:40
= note: inside `std::panicking::r#try::<(), std::panic::AssertUnwindSafe<std::boxed::Box<dyn std::ops::FnOnce() + std::marker::Send>>>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:456:19
= note: inside `std::panic::catch_unwind::<std::panic::AssertUnwindSafe<std::boxed::Box<dyn std::ops::FnOnce() + std::marker::Send>>, ()>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panic.rs:137:14
= note: inside `tests::test::run_test_in_process` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:598:18
= note: inside closure at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:492:39
= note: inside `tests::test::run_test::run_test_inner` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:530:13
= note: inside `tests::test::run_test` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:562:28
= note: inside `tests::test::run_tests::<[closure@tests::test::run_tests_console::{closure#2}]>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:305:17
= note: inside `tests::test::run_tests_console` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/console.rs:290:5
= note: inside `tests::test::test_main` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:116:15
= note: inside `tests::test::test_main_static` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/test/src/lib.rs:135:5
= note: inside `main`
= note: inside `<fn() as std::ops::FnOnce<()>>::call_once - shim(fn())` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/ops/function.rs:227:5
= note: inside `std::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/sys_common/backtrace.rs:122:18
= note: inside closure at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/rt.rs:145:18
= note: inside `std::ops::function::impls::<impl std::ops::FnOnce<()> for &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>::call_once` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/ops/function.rs:259:13
= note: inside `std::panicking::r#try::do_call::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:492:40
= note: inside `std::panicking::r#try::<i32, &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:456:19
= note: inside `std::panic::catch_unwind::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panic.rs:137:14
= note: inside closure at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/rt.rs:128:48
= note: inside `std::panicking::r#try::do_call::<[closure@std::rt::lang_start_internal::{closure#2}], isize>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:492:40
= note: inside `std::panicking::r#try::<isize, [closure@std::rt::lang_start_internal::{closure#2}]>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panicking.rs:456:19
= note: inside `std::panic::catch_unwind::<[closure@std::rt::lang_start_internal::{closure#2}], isize>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/panic.rs:137:14
= note: inside `std::rt::lang_start_internal` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/rt.rs:128:20
= note: inside `std::rt::lang_start::<()>` at /home/ben/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/rt.rs:144:17
= note: this error originates in the attribute macro `test` (in Nightly builds, run with -Z macro-backtrace for more info)
error: aborting due to previous error
error: test failed, to rerun pass '--bin scratch'
```
After:
```
Finished test [unoptimized + debuginfo] target(s) in 0.00s
Running unittests (target/miri/x86_64-unknown-linux-gnu/debug/deps/scratch-9d7717efc37bb64c)
running 1 test
test tests::it_works ... error: Undefined Behavior: type validation failed: encountered a dangling reference (address 0x1 is unallocated)
--> src/main.rs:16:35
|
16 | let _x: &'static u8 = core::mem::transmute(1usize);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a dangling reference (address 0x1 is unallocated)
|
= 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 `tests::it_works` at src/main.rs:16:35
note: inside closure at src/main.rs:14:5
--> src/main.rs:14:5
|
13 | #[test]
| ------- in this procedural macro expansion
14 | / fn it_works() {
15 | | unsafe {
16 | | let _x: &'static u8 = core::mem::transmute(1usize);
17 | | }
18 | | }
| |_____^
= note: this error originates in the attribute macro `test` (in Nightly builds, run with -Z macro-backtrace for more info)
note: Some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace.
error: aborting due to previous error
error: test failed, to rerun pass '--bin scratch'
```
Previously, Miri would always print a backtrace including all frames
when encountering an error. This adds -Zmiri-backtrace which defaults
to 1, internally called BacktraceStyle::Short. By default, backtraces
are pruned to start at __rust_begin_short_backtrace, similar to std.
Then we also remove non-local frames from the bottom of the trace.
This cleans up the last one or two shims outside main or a test.
Users can opt out of pruning by setting -Zmiri-backtrace=full, and will
be automatically opted out if there are no local frames because that
means the reported error is likely in the Rust runtime, which this
pruning is crafted to remove.
exclude mutable references to !Unpin types from uniqueness guarantees
This basically works around https://github.com/rust-lang/unsafe-code-guidelines/issues/148 by not requiring uniqueness any more for mutable references to self-referential generators. That corresponds to [the same work-around that was applied in rustc itself](b815532674/compiler/rustc_middle/src/ty/layout.rs (L2482)).
I am not entirely sure if this is a good idea since it might hide too many errors in case types are "accidentally" `!Unpin`. OTOH, our test suite still passes, and to my knowledge the vast majority of types is `Unpin`. (`place.layout.ty` is monomorphic, we should always exactly know which type this is.)
When two objects directly follow each other in memory, what is the
provenance of an integer cast to a pointer that points directly between
them? For a zero-size region, it could point into the end of the first
object, or the start of the second.
We can avoid answering this difficult question by simply never
allocating two objects directly beside each other. This fixes some of
the false positives from #1866.
This commit adds a `-Zmiri-check-number-initialization` flag to check
that integers and floats are initialized.
This commit also changes some shims to write at type `MaybeUninit<...>`
in order to prevent spurious errors from the uninit check.
add support for `#[global_allocator]`
This PR adds support for custom global allocators. Unfortunately, the code given in #1207 still causes errors when used with box. I believe this is because Box is special-cased in miri and stacked borrows.
Previously the command line string would have been incorrectly constructed if argv[0] contained a doublequote (`"`) or ended in a trailing backslash (`\`). This is a very rare edge case because, by convention, argv[0] is the path to the application and Windows file names cannot contain doublequotes.
Fixes#1881
add support for `#[start]`
This PR adds support for the `#[start]` attribute and fixes#1825.
It also renames `eval_main` to `eval_entry` to reflect that it can evaluate any entry function.
Add support for the `volatile_set_memory` intrinsic
Add support for the unstable `volatile_set_memory` intrinsic
(Runtime behaviour and soundness requirements for `volatile_set_memory` are identical to those of `write_bytes`, so supporting this intrinsic is trivial.)
also ignore 'thread leaks' with -Zmiri-ignore-leaks
This is a step towards https://github.com/rust-lang/miri/issues/1371. The remaining hard part would be supporting checking for memory leaks when there are threads still running. For now we elegantly avoid this problem by using the same flag to control both of these checks. :)
Change the code to either `EACCES` (if the op is performed on the
path), or `EBADF` (if the op is performed the fd)
Updated ops: `stat`, `opendir`, `ftruncate64`, and `readlink`
Add a new test for fs ops in isolation.
Update posix fs shims to use new API `reject_in_isolation`, which
allows rejection with error code instead of always forcing abort.
Error code chosen for each op is the most appropriate one from the
list in corresponding syscall's manual.
Updated helper APIs to not use quotes (`) around input name while
preparing the message. This allows callers to pass multi-word string
like -- "`read` from stdin".
Filter out items other than non-generic functions and statics in our version of `exported_symbols`
[`#[no_mangle]` on a `use` item](https://docs.rs/brotli-decompressor/2.3.1/src/brotli_decompressor/ffi/mod.rs.html#3-5) can make Miri ICE when compiling a dependency (rust-lang/rust#86261):
```rs
#[no_mangle]
use std::{thread,panic, io, boxed, any, string};
```
<details>
```
error: internal compiler error: compiler/rustc_middle/src/ty/mod.rs:1650:13: item_name: no name for DefPath { data: [DisambiguatedDefPathData { data: Misc, disambiguator: 14 }], krate: crate0 }
thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1007:9
stack backtrace:
0: std::panicking::begin_panic
1: std::panic::panic_any
2: rustc_errors::HandlerInner::bug
3: rustc_errors::Handler::bug
4: rustc_middle::ty::context::tls::with_opt
5: rustc_middle::util:🐛:opt_span_bug_fmt
6: rustc_middle::util:🐛:bug_fmt
7: rustc_middle::ty::<impl rustc_middle::ty::context::TyCtxt>::item_name
8: rustc_symbol_mangling::symbol_name_provider
9: rustc_query_impl::<impl rustc_query_system::query::config::QueryAccessors<rustc_query_impl::plumbing::QueryCtxt> for rustc_query_impl::queries::symbol_name>::compute
10: rustc_query_system::query::plumbing::get_query_impl
11: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::symbol_name
12: rustc_middle::middle::exported_symbols::ExportedSymbol::symbol_name_for_local_instance
13: rustc_codegen_ssa:🔙:symbol_export::symbol_name_for_instance_in_crate
14: rustc_codegen_ssa:🔙:linker::exported_symbols
15: <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold
16: rustc_codegen_ssa:🔙:linker::LinkerInfo::new
17: rustc_codegen_ssa:🔙:write::start_async_codegen
18: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate
19: rustc_interface::passes::QueryContext::enter
20: rustc_interface::queries::Queries::ongoing_codegen
21: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
22: rustc_span::with_source_map
23: rustc_interface::interface::create_compiler_and_run
24: rustc_span::with_session_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
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-nightly (a50d72158 2021-06-08) running on x86_64-unknown-linux-gnu
note: compiler flags: -C embed-bitcode=no -C debuginfo=1 --crate-type lib
note: some of the compiler flags provided by cargo are hidden
query stack during panic:
#0 [symbol_name] computing the symbol for `{misc#14}`
end of query stack
```
</details>
This might be because in #1776, we override the `exported_symbols` query, and our version of `exported_symbols` can return a `use` item which don't have a name if the `use` item is tagged with `#[no_mangle]`, and then:
- `rustc_codegen_ssa:🔙:symbol_export::symbol_name_for_instance_in_crate` is called for for every `exported_symbols`: fb3ea63d9b/compiler/rustc_codegen_ssa/src/back/linker.rs (L1300-L1304)
- it calls `rustc_middle::middle::exported_symbols::ExportedSymbol::symbol_name_for_local_instance`: fb3ea63d9b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs (L412)
- which calls `rustc_symbol_mangling::symbol_name_provider`: fb3ea63d9b/compiler/rustc_middle/src/middle/exported_symbols.rs (L37-L44)
- which calls `item_name`: fb3ea63d9b/compiler/rustc_symbol_mangling/src/lib.rs (L216), which triggers the ICE
It might also be problematic for d39f0c64b8/src/shims/foreign_items.rs (L165) which also uses `item_name`, but Miri cannot compile the dependency, so that code can't be reached.
Therefore, this PR makes `exported_symbols` filter out all items that are not functions or statics, so all items returned will have a name, which avoids the ICE (I have tested it in the https://github.com/jorgecarleitao/arrow2 repository).
(This PR also includes a commit that fixes a small (unrelated) bug for `#[no_mangle]` on associated functions -- I found that because I notice `#[no_mangle]` is supported on associated functions and they should not be filtered out in `exported_symbols`.)
Fixes (when the submodule is bumped) rust-lang/rust#86261.
Report an error if a `#[no_mangle]`/`#[export_name = ...]` function has the same symbol name as a built-in shim
Implements https://github.com/rust-lang/miri/pull/1776#issuecomment-821322605.
The error looks like this:
```
error: found `malloc` symbol definition that clashes with a built-in shim
--> tests/compile-fail/function_calls/exported_symbol_shim_clashing.rs:12:9
|
12 | malloc(0);
| ^^^^^^^^^ found `malloc` symbol definition that clashes with a built-in shim
|
help: the `malloc` symbol is defined here
--> tests/compile-fail/function_calls/exported_symbol_shim_clashing.rs:2:1
|
2 | / extern "C" fn malloc(_: usize) -> *mut std::ffi::c_void {
3 | | //~^ HELP the `malloc` symbol is defined here
4 | | unreachable!()
5 | | }
| |_^
= note: inside `main` at tests/compile-fail/function_calls/exported_symbol_shim_clashing.rs:12:9
```
This does not implement "better error messages than we do currently for arg/ABI mismatches" in https://github.com/rust-lang/miri/pull/1776#issuecomment-821343175 -- I failed to remove all `check_arg_count()` and `check_abi()` (they are still used in `src/shims/intrinsics.rs` and `call_dlsym()`) and they don't receive the name of the shim.
Add support for panicking in the emulated application when unsupported functionality is encountered
This PR fixes#1807 and allows an optional flag to be specified to panic when an unsupported syscall is encountered. In essence, instead of bubbling up an error in the context of the Miri application Miri will panic within the context of the *emulated* application. This feature is desired to allow CI pipelines to determine if a Miri failure is unsupported functionality or actual UB. Please read [this comment](https://github.com/rust-lang/miri/issues/1807#issuecomment-845425076) for the rationale behind this change.
Note: this change does not cover all cases where unsupported functionality errors may be raised. If you search the repo for `throw_unsup_format!` there are many cases that I think are less likely to occur and may still be problematic for some folks.
TODO:
- [x] README documentation on this new flag
- [x] Add tests
In user interface, added a new flag `-Zmiri-isolation-error` which
takes one of the four values -- hide, warn, warn-nobacktrace, and
abort. This option can be used to configure Miri to either abort or
return an error code upon executing isolated op. If not aborted, Miri
prints a warning, whose verbosity can be configured using this flag.
In implementation, added a new enum `IsolatedOp` to capture all the
settings related to ops requiring communication with the
host. Old `communicate` flag in both miri configs and machine
stats is replaced with a new helper function `communicate()` which
checks `isolated_op` internally.
Added a new helper function `reject_in_isolation` which can be called
by shims to reject ops according to the reject_with settings. Use miri
specific diagnostics function `report_msg` to print backtrace in the
warning. Update it to take an enum value instead of a bool, indicating
the level of diagnostics.
Updated shims related to current dir to use the new APIs. Added a new
test for current dir ops in isolation without halting machine.
