Unify and improve const-prop lints
Add a single helper method for all lints emitted by const-prop, and make that lint different from the CTFE `const_err` lint. Also consistently check overflow on *arithmetic*, not on the assertion, to make behavior the same for debug and release builds.
See [this summary comment](https://github.com/rust-lang/rust/pull/69185#issuecomment-587924754) for details and the latest status.
In terms of lint formatting, I went for what seems to be the better style: have a general message above the code, and then a specific message at the span:
```
error: this arithmetic operation will overflow
--> $DIR/const-err2.rs:21:18
|
LL | let a_i128 = -std::i128::MIN;
| ^^^^^^^^^^^^^^^ attempt to negate with overflow
```
We could also just have the specific message above and no text at the span if that is preferred.
I also converted some of the existing tests to use compiletest revisions, so that the same test can check a bunch of different compile flags.
Fixes https://github.com/rust-lang/rust/issues/69020.
Helps with https://github.com/rust-lang/rust/issues/69021: debug/release are now consistent, but the assoc-const test in that issue still fails (there is a FIXME in the PR for this). The reason seems to be that const-prop notices the assoc const in `T::N << 42` and does not even bother calling `const_prop` on that operation.
Has no effect on https://github.com/rust-lang/rust/issues/61821; the duplication there has entirely different reasons.
The test checks that we reuse the CGU of a crate when the implementation
details of an `extern crate` have changed.
Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>
This test does not actually emit any warnings, since
`#![allow(warnings)]` was specified. `compiletest` was erroneously
ignoring `//~` tests and looking only for `//[X]~` ones. As a result of
the changes in the previous commit, we now look for `//~` comments in
incremental tests and expect them to appear in *all* revisions.
Making ICEs and test them in incremental
This adds:
- A way to make the compiler ICE
- A way to check for ICE in `cfail` tests with `should-ice`
- A regression test for issue #65401
I am not sure the attribute added `should-ice` is the best for this job
perf.rlo shows that running the `ConstProp` pass results in
across-the-board wins regardless of debug or opt complilation mode. As a
result, we're turning it on to get the compile time benefits.
`ConstProp` doesn't currently intern the memory used by its `Machine` so
we can't yet propagate allocations which is why
`ConstProp::should_const_prop()` checks if the value being propagated is
a scalar or not.
[mir-opt] Handle return place in ConstProp and improve SimplifyLocals pass
Temporarily rebased on top of #66074. The top 2 commits are new.
r? @oli-obk
Passes LLVM codegen and Emscripten link-time flags for exception
handling if and only if the panic strategy is `unwind`. Sets the
default panic strategy for Emscripten targets to `unwind`. Re-enables
tests that depend on unwinding support for Emscripten, including
`should_panic` tests.
Fix `canonicalize_const_var` leaking inference variables
Fixes#61338Fixes#61516Fixes#62536Fixes#64087Fixes#64863Fixes#65623
I added regression tests for all these issues apart from #64863, which is very similar to #61338.
r? @varkor
The `ConstProp` can cause many locals to be initialized to a constant
value and then never read from. `ConstProp` can also evaluate ZSTs into
constant values. Previously, many of these would be removed by other
parts of the MIR optimization pipeline. However, evaluating ZSTs
(especially `()`) into constant values defeated those parts of the
optimizer and so in a2e3ed5c05, I added a
hack to `ConstProp` that skips evaluating ZSTs to avoid that regression.
This commit changes `SimplifyLocals` so that it doesn't consider writes
of const values to a local to be a use of that local. In doing so,
`SimplifyLocals` is able to remove otherwise unused locals left behind
by other optimization passes (`ConstProp` in particular).
- Compatible with Emscripten 1.38.46-upstream or later upstream.
- Refactors the Emscripten target spec to share code with other wasm
targets.
- Replaces the old incorrect wasm32 C call ABI with the correct one,
preserving the old one as wasm32_bindgen_compat for wasm-bindgen
compatibility.
- Updates the varargs ABI used by Emscripten and deletes the old one.
- Removes the obsolete wasm32-experimental-emscripten target.
- Uses EMCC_CFLAGS on CI to avoid the timeout problems with #63649.
compiletest: Introduce `// {check,build,run}-pass` pass modes
Pass UI tests now have three modes
```
// check-pass
// build-pass
// run-pass
```
mirroring equivalent well-known `cargo` commands.
`// check-pass` will compile the test skipping codegen (which is expensive and isn't supposed to fail in most cases).
`// build-pass` will compile and link the test without running it.
`// run-pass` will compile, link and run the test.
Tests without a "pass" annotation are still considered "fail" tests.
Most UI tests would probably want to switch to `check-pass`.
Tests validating codegen would probably want to run the generated code as well and use `run-pass`.
`build-pass` should probably be rare (linking tests?).
https://github.com/rust-lang/rust/pull/61755 will provide a way to run the tests with any mode, e.g. bump `check-pass` tests to `run-pass` to satisfy especially suspicious people, and be able to make sure that codegen doesn't breaks in some entirely unexpected way.
Tests marked with any mode are expected to pass with any other mode, if that's not the case for some legitimate reason, then the test should be made a "fail" test rather than a "pass" test.
Perhaps some secondary CI can verify this invariant, but that's not super urgent.
`// compile-pass` still works and is equivalent to `build-pass`.
Why is `// compile-pass` bad - 1) it gives an impression that the test is only compiled, but not linked, 2) it doesn't mirror a cargo command.
It can be removed some time in the future in a separate PR.
cc https://github.com/rust-lang/rust/issues/61712
`ByRef` const values have no identity beyond their value, we should not treat them as having identity. The `AllocId` often differed between equal constants, because of the way that the miri-engine evaluates constants.
Added ignore-sgx for appropriate tests in src/test
These are all the tests that make sense to ignore when targeting fortanix-unknonw-sgx, at least in test/runpass. Other suites not yet covered.
