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Lower transmutes from int to pointer type as gep on null #121282
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@bors try @rust-timer queue |
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…e, r=<try> Lower transmutes from int to pointer type as gep on null I thought of this while looking at rust-lang#121242 The UI test that's being changed here crashes without changing the transmutes into casts. Based on that, this PR should not be merged without a crater build-and-test run.
☀️ Try build successful - checks-actions |
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Finished benchmarking commit (d073071): comparison URL. Overall result: no relevant changes - no action neededBenchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf. @bors rollup=never Instruction countThis benchmark run did not return any relevant results for this metric. Max RSS (memory usage)ResultsThis is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
CyclesResultsThis is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
Binary sizeResultsThis is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
Bootstrap: 640.336s -> 641.418s (0.17%) |
@craterbot run mode=build-and-test |
👌 Experiment ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more |
@craterbot abort |
🗑️ Experiment ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more |
@craterbot run mode=build-and-test start=master#61223975d46f794466efa832bc7562b9707ecc46+rustflags=-Copt-level=3 end=try#d073071d77ce0f93b4fd8cc567a1e2b9e1b22126+rustflags=-Copt-level=3 |
👌 Experiment ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more |
tests/codegen/transmute-scalar.rs
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@@ -49,7 +49,7 @@ pub fn ptr_to_int(p: *mut u16) -> usize { | |||
} | |||
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// CHECK: define{{.*}}ptr @int_to_ptr([[USIZE]] %i) | |||
// CHECK: %_0 = inttoptr [[USIZE]] %i to ptr | |||
// CHECK: %_0 = getelementptr i8, ptr null, i64 %i |
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I think to make this pass on non-64-bit you need
// CHECK: %_0 = getelementptr i8, ptr null, i64 %i | |
// CHECK: %_0 = getelementptr i8, ptr null, [[USIZE]] %i |
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☀️ Test successful - checks-actions |
Finished benchmarking commit (0fa7fea): comparison URL. Overall result: no relevant changes - no action needed@rustbot label: -perf-regression Instruction countThis benchmark run did not return any relevant results for this metric. Max RSS (memory usage)ResultsThis is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
CyclesThis benchmark run did not return any relevant results for this metric. Binary sizeThis benchmark run did not return any relevant results for this metric. Bootstrap: 672.319s -> 672.448s (0.02%) |
Ignore some more crates Adding all the spurious failures I identified in rust-lang/rust#121282 (comment) I'm also not sure what `blacklist.md` is for, but it hasn't been updated in 6 years so I imagine it's not important.
Ignore some more crates Adding all the spurious failures I identified in rust-lang/rust#121282 (comment) I'm also not sure what `blacklist.md` is for, but it hasn't been updated in 6 years so I imagine it's not important.
Ignore some more crates Adding all the spurious failures I identified in rust-lang/rust#121282 (comment) I'm also not sure what `blacklist.md` is for, but it hasn't been updated in 6 years so I imagine it's not important.
transmute: caution against int2ptr transmutation This came up in rust-lang#121282. Cc `@saethlin` `@scottmcm` Eventually we'll add a proper description of provenance that we can reference, but that's a bunch of work and it's unclear who will have the time to do that when. Meanwhile, let's at least do what we can without mentioning provenance explicitly.
transmute: caution against int2ptr transmutation This came up in rust-lang#121282. Cc ``@saethlin`` ``@scottmcm`` Eventually we'll add a proper description of provenance that we can reference, but that's a bunch of work and it's unclear who will have the time to do that when. Meanwhile, let's at least do what we can without mentioning provenance explicitly.
transmute: caution against int2ptr transmutation This came up in rust-lang#121282. Cc ```@saethlin``` ```@scottmcm``` Eventually we'll add a proper description of provenance that we can reference, but that's a bunch of work and it's unclear who will have the time to do that when. Meanwhile, let's at least do what we can without mentioning provenance explicitly.
transmute: caution against int2ptr transmutation This came up in rust-lang#121282. Cc ````@saethlin```` ````@scottmcm```` Eventually we'll add a proper description of provenance that we can reference, but that's a bunch of work and it's unclear who will have the time to do that when. Meanwhile, let's at least do what we can without mentioning provenance explicitly.
transmute: caution against int2ptr transmutation This came up in rust-lang#121282. Cc `````@saethlin````` `````@scottmcm````` Eventually we'll add a proper description of provenance that we can reference, but that's a bunch of work and it's unclear who will have the time to do that when. Meanwhile, let's at least do what we can without mentioning provenance explicitly.
Rollup merge of rust-lang#122379 - RalfJung:int2ptr-transmute, r=m-ou-se transmute: caution against int2ptr transmutation This came up in rust-lang#121282. Cc ```@saethlin``` ```@scottmcm``` Eventually we'll add a proper description of provenance that we can reference, but that's a bunch of work and it's unclear who will have the time to do that when. Meanwhile, let's at least do what we can without mentioning provenance explicitly.
transmute: caution against int2ptr transmutation This came up in rust-lang#121282. Cc ```@saethlin``` ```@scottmcm``` Eventually we'll add a proper description of provenance that we can reference, but that's a bunch of work and it's unclear who will have the time to do that when. Meanwhile, let's at least do what we can without mentioning provenance explicitly.
Pkgsrc changes: * Adapt checksums and patches, some have beene intregrated upstream. Upstream chnages: Version 1.78.0 (2024-05-02) =========================== Language -------- - [Stabilize `#[cfg(target_abi = ...)]`] (rust-lang/rust#119590) - [Stabilize the `#[diagnostic]` namespace and `#[diagnostic::on_unimplemented]` attribute] (rust-lang/rust#119888) - [Make async-fn-in-trait implementable with concrete signatures] (rust-lang/rust#120103) - [Make matching on NaN a hard error, and remove the rest of `illegal_floating_point_literal_pattern`] (rust-lang/rust#116284) - [static mut: allow mutable reference to arbitrary types, not just slices and arrays] (rust-lang/rust#117614) - [Extend `invalid_reference_casting` to include references casting to bigger memory layout] (rust-lang/rust#118983) - [Add `non_contiguous_range_endpoints` lint for singleton gaps after exclusive ranges] (rust-lang/rust#118879) - [Add `wasm_c_abi` lint for use of older wasm-bindgen versions] (rust-lang/rust#117918) This lint currently only works when using Cargo. - [Update `indirect_structural_match` and `pointer_structural_match` lints to match RFC] (rust-lang/rust#120423) - [Make non-`PartialEq`-typed consts as patterns a hard error] (rust-lang/rust#120805) - [Split `refining_impl_trait` lint into `_reachable`, `_internal` variants] (rust-lang/rust#121720) - [Remove unnecessary type inference when using associated types inside of higher ranked `where`-bounds] (rust-lang/rust#119849) - [Weaken eager detection of cyclic types during type inference] (rust-lang/rust#119989) - [`trait Trait: Auto {}`: allow upcasting from `dyn Trait` to `dyn Auto`] (rust-lang/rust#119338) Compiler -------- - [Made `INVALID_DOC_ATTRIBUTES` lint deny by default] (rust-lang/rust#111505) - [Increase accuracy of redundant `use` checking] (rust-lang/rust#117772) - [Suggest moving definition if non-found macro_rules! is defined later] (rust-lang/rust#121130) - [Lower transmutes from int to pointer type as gep on null] (rust-lang/rust#121282) Target changes: - [Windows tier 1 targets now require at least Windows 10] (rust-lang/rust#115141) - [Enable CMPXCHG16B, SSE3, SAHF/LAHF and 128-bit Atomics in tier 1 Windows] (rust-lang/rust#120820) - [Add `wasm32-wasip1` tier 2 (without host tools) target] (rust-lang/rust#120468) - [Add `wasm32-wasip2` tier 3 target] (rust-lang/rust#119616) - [Rename `wasm32-wasi-preview1-threads` to `wasm32-wasip1-threads`] (rust-lang/rust#122170) - [Add `arm64ec-pc-windows-msvc` tier 3 target] (rust-lang/rust#119199) - [Add `armv8r-none-eabihf` tier 3 target for the Cortex-R52] (rust-lang/rust#110482) - [Add `loongarch64-unknown-linux-musl` tier 3 target] (rust-lang/rust#121832) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Bump Unicode to version 15.1.0, regenerate tables] (rust-lang/rust#120777) - [Make align_offset, align_to well-behaved in all cases] (rust-lang/rust#121201) - [PartialEq, PartialOrd: document expectations for transitive chains] (rust-lang/rust#115386) - [Optimize away poison guards when std is built with panic=abort] (rust-lang/rust#100603) - [Replace pthread `RwLock` with custom implementation] (rust-lang/rust#110211) - [Implement unwind safety for Condvar on all platforms] (rust-lang/rust#121768) - [Add ASCII fast-path for `char::is_grapheme_extended`] (rust-lang/rust#121138) Stabilized APIs --------------- - [`impl Read for &Stdin`] (https://doc.rust-lang.org/stable/std/io/struct.Stdin.html#impl-Read-for-%26Stdin) - [Accept non `'static` lifetimes for several `std::error::Error` related implementations] (rust-lang/rust#113833) - [Make `impl<Fd: AsFd>` impl take `?Sized`] (rust-lang/rust#114655) - [`impl From<TryReserveError> for io::Error`] (https://doc.rust-lang.org/stable/std/io/struct.Error.html#impl-From%3CTryReserveError%3E-for-Error) These APIs are now stable in const contexts: - [`Barrier::new()`] (https://doc.rust-lang.org/stable/std/sync/struct.Barrier.html#method.new) Cargo ----- - [Stabilize lockfile v4](rust-lang/cargo#12852) - [Respect `rust-version` when generating lockfile] (rust-lang/cargo#12861) - [Control `--charset` via auto-detecting config value] (rust-lang/cargo#13337) - [Support `target.<triple>.rustdocflags` officially] (rust-lang/cargo#13197) - [Stabilize global cache data tracking] (rust-lang/cargo#13492) Misc ---- - [rustdoc: add `--test-builder-wrapper` arg to support wrappers such as RUSTC_WRAPPER when building doctests] (rust-lang/rust#114651) Compatibility Notes ------------------- - [Many unsafe precondition checks now run for user code with debug assertions enabled] (rust-lang/rust#120594) This change helps users catch undefined behavior in their code, though the details of how much is checked are generally not stable. - [riscv only supports split_debuginfo=off for now] (rust-lang/rust#120518) - [Consistently check bounds on hidden types of `impl Trait`] (rust-lang/rust#121679) - [Change equality of higher ranked types to not rely on subtyping] (rust-lang/rust#118247) - [When called, additionally check bounds on normalized function return type] (rust-lang/rust#118882) - [Expand coverage for `arithmetic_overflow` lint] (rust-lang/rust#119432) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Update to LLVM 18](rust-lang/rust#120055) - [Build `rustc` with 1CGU on `x86_64-pc-windows-msvc`] (rust-lang/rust#112267) - [Build `rustc` with 1CGU on `x86_64-apple-darwin`] (rust-lang/rust#112268) - [Introduce `run-make` V2 infrastructure, a `run_make_support` library and port over 2 tests as example] (rust-lang/rust#113026) - [Windows: Implement condvar, mutex and rwlock using futex] (rust-lang/rust#121956)
…Cell` Reduces the amount of `unsafe` in the code. Looks like in newer rustc versions, this causes crashes. Could be related to rust-lang/rust#121282
Is there a difference between casting an
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Yes there is a difference. To quote the RFC https://rust-lang.github.io/rfcs/3559-rust-has-provenance.html
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OK, thanks, this clears stuff up 👍 |
@Liorst4 Reminder that you can also confirm this using Miri. This PR changed only codegen, which doesn't affect Miri, but your
(Miri has diagnosed this for a long time; this PR just means that LLVM also knows about the UB.) |
I thought of this while looking at #121242. See that PR's description for why this lowering is preferable.
The UI test that's being changed here crashes without changing the transmutes into casts. Based on that, this PR should not be merged without a crater build-and-test run.