about summary refs log tree commit diff
path: root/tests/codegen
AgeCommit message (Collapse)AuthorLines
2024-12-15Simplify the GEP instruction for indexDianQK-0/+59
2024-12-13Auto merge of #133899 - scottmcm:strip-mir-debuginfo, r=oli-obkbors-2/+3
We don't need `NonNull::as_ptr` debuginfo In order to stop pessimizing the use of local variables in core, skip debug info for MIR temporaries in tiny (single-BB) functions. For functions as simple as this -- `Pin::new`, etc -- nobody every actually wants debuginfo for them in the first place. They're more like intrinsics than real functions, and stepping over them is good.
2024-12-13Stabilize async closuresMichael Goulet-2/+0
2024-12-11Auto merge of #128004 - folkertdev:naked-fn-asm, r=Amanieubors-77/+318
codegen `#[naked]` functions using global asm tracking issue: https://github.com/rust-lang/rust/issues/90957 Fixes #124375 This implements the approach suggested in the tracking issue: use the existing global assembly infrastructure to emit the body of `#[naked]` functions. The main advantage is that we now have full control over what gets generated, and are no longer dependent on LLVM not sneakily messing with our output (inlining, adding extra instructions, etc). I discussed this approach with `@Amanieu` and while I think the general direction is correct, there is probably a bunch of stuff that needs to change or move around here. I'll leave some inline comments on things that I'm not sure about. Combined with https://github.com/rust-lang/rust/pull/127853, if both accepted, I think that resolves all steps from the tracking issue. r? `@Amanieu`
2024-12-11coverage: Adjust a codegen test to ignore the order of covmap/covfun globalsZalathar-4/+2
2024-12-10make naked function generics test stricterFolkert de Vries-4/+5
2024-12-10fix the `naked-asan` testFolkert de Vries-5/+2
we get these declarations ``` ; opt level 0 declare x86_intrcc void @page_fault_handler(ptr byval([8 x i8]) align 8, i64) unnamed_addr #1 ; opt level > 0 declare x86_intrcc void @page_fault_handler(ptr noalias nocapture noundef byval([8 x i8]) align 8 dereferenceable(8), i64 noundef) unnamed_addr #1 ``` The space after `i64` in the original regex made the regex not match for opt level 0. Removing the space fixes the issue. ``` declare x86_intrcc void @page_fault_handler(ptr {{.*}}, i64 {{.*}}){{.*}}#[[ATTRS:[0-9]+]] ```
2024-12-10codegen `#[naked]` functions using `global_asm!`Folkert-73/+316
2024-12-10We don't need `NonNull::as_ptr` debuginfoScott McMurray-2/+3
Stop pessimizing the use of local variables in core by skipping debug info for MIR temporaries in tiny (single-BB) functions. For functions as simple as this -- `Pin::new`, etc -- nobody every actually wants debuginfo for them in the first place. They're more like intrinsics than real functions, and stepping over them is good.
2024-12-06Rollup merge of #130777 - azhogin:azhogin/reg-struct-return, r=workingjubileeMatthias Krüger-0/+206
rust_for_linux: -Zreg-struct-return commandline flag for X86 (#116973) Command line flag `-Zreg-struct-return` for X86 (32-bit) for rust-for-linux. This flag enables the same behavior as the `abi_return_struct_as_int` target spec key. - Tracking issue: https://github.com/rust-lang/rust/issues/116973
2024-12-05Adapt codegen tests for NUW inferenceTim Neumann-15/+15
2024-12-04Rename `core_pattern_type` and `core_pattern_types` lib feature gates to ↵Oli Scherer-2/+1
`pattern_type_macro` That's what the gates are actually gating, and the single char difference in naming was not helpful either
2024-12-03Rollup merge of #132612 - compiler-errors:async-trait-bounds, r=lcnrMatthias Krüger-1/+1
Gate async fn trait bound modifier on `async_trait_bounds` This PR moves `async Fn()` trait bounds into a new feature gate: `feature(async_trait_bounds)`. The general vibe is that we will most likely stabilize the `feature(async_closure)` *without* the `async Fn()` trait bound modifier, so we need to gate that separately. We're trying to work on the general vision of `async` trait bound modifier general in: https://github.com/rust-lang/rfcs/pull/3710, however that RFC still needs more time for consensus to converge, and we've decided that the value that users get from calling the bound `async Fn()` is *not really* worth blocking landing async closures in general.
2024-12-03Auto merge of #104342 - mweber15:add_file_location_to_more_types, r=wesleywiserbors-0/+112
Require `type_map::stub` callers to supply file information This change attaches file information (`DIFile` reference and line number) to struct debug info nodes. Before: ``` ; foo.ll ... !5 = !DIFile(filename: "<unknown>", directory: "") ... !16 = !DICompositeType(tag: DW_TAG_structure_type, name: "MyType", scope: !2, file: !5, size: 32, align: 32, elements: !17, templateParams: !19, identifier: "4cb373851db92e732c4cb5651b886dd0") ... ``` After: ``` ; foo.ll ... !3 = !DIFile(filename: "foo.rs", directory: "/home/matt/src/rust98678", checksumkind: CSK_SHA1, checksum: "bcb9f08512c8f3b8181ef4726012bc6807bc9be4") ... !16 = !DICompositeType(tag: DW_TAG_structure_type, name: "MyType", scope: !2, file: !3, line: 3, size: 32, align: 32, elements: !17, templateParams: !19, identifier: "9e5968c7af39c148acb253912b7f409f") ... ``` Fixes #98678 r? `@wesleywiser`
2024-12-02Fix tests when using MinGWMatt Weber-4/+4
2024-12-02Gate async fn trait bound modifier on async_trait_boundsMichael Goulet-1/+1
2024-12-02rust_for_linux: -Zreg-struct-return commandline flag for X86 (#116973)Andrew Zhogin-0/+206
2024-11-30Rollup merge of #131551 - taiki-e:ppc-asm-vreg-inout, r=Amanieu许杰友 Jieyou Xu (Joe)-2/+11
Support input/output in vector registers of PowerPC inline assembly This extends currently clobber-only vector registers (`vreg`) support to allow passing `#[repr(simd)]` types as input/output. | Architecture | Register class | Target feature | Allowed types | | ------------ | -------------- | -------------- | -------------- | | PowerPC | `vreg` | `altivec` | `i8x16`, `i16x8`, `i32x4`, `f32x4` | | PowerPC | `vreg` | `vsx` | `f32`, `f64`, `i64x2`, `f64x2` | In addition to floats and `core::simd` types listed above, `core::arch` types and custom `#[repr(simd)]` types of the same size and type are also allowed. All allowed types and relevant target features are currently unstable. r? `@Amanieu` `@rustbot` label +O-PowerPC +A-inline-assembly
2024-11-29Rollup merge of #131323 - jfrimmel:avr-inline-asm-clobber-abi, r=AmanieuMatthias Krüger-0/+43
Support `clobber_abi` in AVR inline assembly This PR implements the `clobber_abi` part necessary to eventually stabilize the inline assembly for AVR. This is tracked in #93335. This is heavily inspired by the sibling-PR #131310 for the MSP430. I've explained my reasoning in the first commit message in detail, which is reproduced below for easier reviewing: This follows the [ABI documentation] of AVR-GCC: > The [...] call-clobbered general purpose registers (GPRs) are registers that might be destroyed (clobbered) by a function call. > > - **R18–R27, R30, R31** > > These GPRs are call clobbered. An ordinary function may use them without restoring the contents. [...] > > - **R0, T-Flag** > > The temporary register and the T-flag in SREG are also call-clobbered, but this knowledge is not exposed explicitly to the compiler (R0 is a fixed register). Therefore this commit lists the aforementioned registers `r18–r27`, `r30` and `r31` as clobbered registers. Since the `r0` register (listed above as well) is not available in inline assembly at all (potentially because the AVR-GCC considers it a fixed register causing the register to never be used in register allocation and LLVM adopting this), there is no need to list it in the clobber list (the `r0`-variant is not even available). A comment was added to ensure, that the `r0` gets added to the clobber-list once the register gets usable in inline ASM. Since the SREG is normally considered clobbered anyways (unless the user supplies the `preserve_flags`-option), there is no need to explicitly list a bit in this register (which is not possible to list anyways). Note, that this commit completely ignores the case of interrupts (that are described in the ABI-specification), since every register touched in an ISR need to be saved anyways. [ABI documentation]: https://gcc.gnu.org/wiki/avr-gcc#Call-Used_Registers r? ``@Amanieu`` ``@rustbot`` label +O-AVR
2024-11-28Auto merge of #123244 - Mark-Simulacrum:share-inline-never-generics, r=saethlinbors-2/+5
Enable -Zshare-generics for inline(never) functions This avoids inlining cross-crate generic items when possible that are already marked inline(never), implying that the author is not intending for the function to be inlined by callers. As such, having a local copy may make it easier for LLVM to optimize but mostly just adds to binary bloat and codegen time. In practice our benchmarks indicate this is indeed a win for larger compilations, where the extra cost in dynamic linking to these symbols is diminished compared to the advantages in fewer copies that need optimizing in each binary. It might also make sense it expand this with other heuristics (e.g., `#[cold]`) in the future, but this seems like a good starting point. FWIW, I expect that doing cleanup in where we make the decision what should/shouldn't be shared is also a good idea. Way too much code needed to be tweaked to check this. But I'm hoping to leave that for a follow-up PR rather than blocking this on it.
2024-11-28Auto merge of #133540 - ehuss:compiletest-proc-macro, r=jieyouxubors-5/+1
Compiletest: add proc-macro header This adds a `proc-macro` header to simplify using proc-macros, and to reduce boilerplate. This header works similar to the `aux-build` header where you pass a path for a proc-macro to be built. This allows the `force-host`, `no-prefer-dynamic` headers, and `crate_type` attribute to be removed. Additionally it uses `--extern` like `aux_crate` (allows implicit `extern crate` in 2018) and `--extern proc_macro` (to place in the prelude in 2018). ~~This also includes a secondary change which defaults the edition of proc-macros to 2024. This further reduces boilerplate (removing `extern crate proc_macro;`), and allows using modern Rust syntax. I was a little on the fence including this. I personally prefer it, but I can imagine it might be confusing to others.~~ EDIT: Removed Some tests were changed so that when there is a chain of dependencies A→B→C, that the `@ proc-macro` is placed in `B` instead of `A` so that the `--extern` flag works correctly (previously it depended on `-L` to find `C`). I think this is better to make the dependencies more explicit. None of these tests looked like the were actually testing this behavior. There is one test that had an unexplained output change: `tests/ui/macros/same-sequence-span.rs`. I do not know why it changed, but it didn't look like it was particularly important. Perhaps there was a normalization issue? This is currently not compatible with the rustdoc `build-aux-docs` header. It can probably be fixed, I'm just not feeling motivated to do that right now. ### Implementation steps - [x] Document this new behavior in rustc-dev-guide once we figure out the specifics. https://github.com/rust-lang/rustc-dev-guide/pull/2149
2024-11-28Share inline(never) generics across cratesMark Rousskov-2/+5
This reduces code sizes and better respects programmer intent when marking inline(never). Previously such a marking was essentially ignored for generic functions, as we'd still inline them in remote crates.
2024-11-29Support #[repr(simd)] types in input/output of PowerPC inline assemblyTaiki Endo-2/+11
2024-11-28Move & rename test case to match naming of #132456Julian Frimmel-0/+0
2024-11-28Add test case for the clobber optionsJulian Frimmel-0/+43
2024-11-28Rollup merge of #133463 - taiki-e:aarch64-asm-x18, r=AmanieuGuillaume Gomez-36/+51
Fix handling of x18 in AArch64 inline assembly on ohos/trusty or with -Zfixed-x18 Currently AArch64 inline assembly allows using x18 on ohos/trusty or with -Zfixed-x18. https://github.com/rust-lang/rust/blob/7db7489f9bc274cb60c4956bfa56de0185eb1b9b/compiler/rustc_target/src/asm/aarch64.rs#L74-L76 However, x18 is reserved in these environments and should not be allowed in the input/output operands of inline assemblies as it is in Android, Windows, etc.. https://github.com/rust-lang/rust/blob/7db7489f9bc274cb60c4956bfa56de0185eb1b9b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_ohos.rs#L19 https://github.com/rust-lang/rust/blob/7db7489f9bc274cb60c4956bfa56de0185eb1b9b/compiler/rustc_target/src/spec/targets/aarch64_unknown_trusty.rs#L18 https://github.com/rust-lang/rust/blob/7db7489f9bc274cb60c4956bfa56de0185eb1b9b/compiler/rustc_codegen_llvm/src/llvm_util.rs#L764-L771 (As for ohos, +reserve-x18 is [redundant](https://github.com/llvm/llvm-project/commit/c417b7a695704d5bc3be23f34d1bfa505f5172de#diff-0ddf23e0bf2b28b2d05f842f087d1e6f694e8e06d1765e8d0f10d47fddcdff9c) since https://github.com/rust-lang/rust/commit/7a966b918870485e9b364e77f50c511f8c2cc275 that starting using llvm's ohos targets. So removed it from target-spec.) This fix may potentially break the code for tier 2 target (aarch64-unknown-linux-ohos). (As for others, aarch64-unknown-trusty is tier 3 and -Zfixed-x18 is unstable so breaking them should be fine.) However, in any case, it seems suspicious that the code that is broken by this was sound. r? `@Amanieu` `@rustbot` label O-AArch64 +A-inline-assembly
2024-11-28Rollup merge of #133452 - taiki-e:hexagon-asm-pred, r=AmanieuGuillaume Gomez-0/+37
Support predicate registers (clobber-only) in Hexagon inline assembly The result of the Hexagon instructions such as comparison, store conditional, etc. is stored in predicate registers (`p[0-3]`), but currently there is no way to mark it as clobbered in `asm!`. This is also needed for `clobber_abi` (although implementing `clobber_abi` will require the addition of support for [several more register classes](https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/Hexagon/HexagonRegisterInfo.cpp#L71-L90). see also https://github.com/rust-lang/rust/issues/93335#issuecomment-2395210055). Refs: - [Section 6 "Conditional Execution" in Qualcomm Hexagon V73 Programmer’s Reference Manual](https://docs.qualcomm.com/bundle/publicresource/80-N2040-53_REV_AB_Qualcomm_Hexagon_V73_Programmers_Reference_Manual.pdf#page=90) - [Register definition in LLVM](https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/Hexagon/HexagonRegisterInfo.td#L155) cc `@androm3da` (target maintainer of hexagon-unknown-{[none-elf](https://doc.rust-lang.org/nightly/rustc/platform-support/hexagon-unknown-none-elf.html#target-maintainers),[linux-musl](https://doc.rust-lang.org/nightly/rustc/platform-support/hexagon-unknown-linux-musl.html#target-maintainers)}) r? `@Amanieu` `@rustbot` label +A-inline-assembly (Currently there is no O-hexagon label...)
2024-11-28Rollup merge of #133422 - taiki-e:riscv-e-clobber-abi, r=AmanieuGuillaume Gomez-0/+44
Fix clobber_abi in RV32E and RV64E inline assembly Currently clobber_abi in RV32E and RV64E inline assembly is implemented using InlineAsmClobberAbi::RiscV, but broken since x16-x31 cannot be used in RV32E and RV64E. ``` error: cannot use register `x16`: register can't be used with the `e` target feature --> <source>:42:14 | 42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags)); | ^^^^^^^^^^^^^^^^ error: cannot use register `x17`: register can't be used with the `e` target feature --> <source>:42:14 | 42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags)); | ^^^^^^^^^^^^^^^^ error: cannot use register `x28`: register can't be used with the `e` target feature --> <source>:42:14 | 42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags)); | ^^^^^^^^^^^^^^^^ error: cannot use register `x29`: register can't be used with the `e` target feature --> <source>:42:14 | 42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags)); | ^^^^^^^^^^^^^^^^ error: cannot use register `x30`: register can't be used with the `e` target feature --> <source>:42:14 | 42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags)); | ^^^^^^^^^^^^^^^^ error: cannot use register `x31`: register can't be used with the `e` target feature --> <source>:42:14 | 42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags)); | ^^^^^^^^^^^^^^^^ ``` r? `@Amanieu` `@rustbot` label O-riscv +A-inline-assembly
2024-11-27Update tests to use new proc-macro headerEric Huss-5/+1
2024-11-26Fix handling of x18 in AArch64 inline assembly on ohos/trusty or with ↵Taiki Endo-36/+51
-Zfixed-x18
2024-11-25Update test expectations to accept LLVM 'initializes' attributeHans Wennborg-1/+1
The test was checking for two `ptr` arguments by matching commas (or non-commas), however after https://github.com/llvm/llvm-project/pull/117104 LLVM adds an `initializes((0, 16))` attribute, which includes a comma. So instead, we make the test check for two LLVM values, i.e. something prefixed by %. (See also https://crbug.com/380707238)
2024-11-25Support predicate registers (clobber-only) in Hexagon inline assemblyTaiki Endo-0/+37
2024-11-25Fix clobber_abi in RV32E and RV64E inline assemblyTaiki Endo-0/+44
2024-11-24Make asm_goto_with_outputs a separate feature gateGary Guo-1/+1
2024-11-24Support use of asm goto with outputs and `options(noreturn)`Gary Guo-1/+11
When labels are present, the `noreturn` option really means that asm block won't fallthrough -- if labels are present, then outputs can still be meaningfully used.
2024-11-24Fix asm goto with outputsGary Guo-11/+13
When outputs are used together with labels, they are considered to be written for all destinations, not only when falling through.
2024-11-23Rollup merge of #127483 - BertalanD:no_sanitize-global-var, r=rcvalle许杰友 Jieyou Xu (Joe)-0/+10
Allow disabling ASan instrumentation for globals AddressSanitizer adds instrumentation to global variables unless the [`no_sanitize_address`](https://llvm.org/docs/LangRef.html#global-attributes) attribute is set on them. This commit extends the existing `#[no_sanitize(address)]` attribute to set this; previously it only had the desired effect on functions. (cc https://github.com/rust-lang/rust/issues/39699)
2024-11-22Rollup merge of #133102 - RalfJung:aarch64-softfloat, r=davidtwco,wesleywiserMichael Goulet-0/+48
aarch64 softfloat target: always pass floats in int registers This is a part of https://github.com/rust-lang/rust/issues/131058: on softfloat aarch64 targets, the float registers may be unavailable. And yet, LLVM will happily use them to pass float types if the corresponding target features are enabled. That's a problem as it means enabling/disabling `neon` instructions can change the ABI. Other targets have a `soft-float` target feature that forces the use of the soft-float ABI no matter whether float registers are enabled or not; aarch64 has nothing like that. So we follow the aarch64 [softfloat ABI](https://github.com/rust-lang/rust/issues/131058#issuecomment-2385027423) and treat floats like integers for `extern "C"` functions. For the "Rust" ABI, we do the same for scalars, and then just do something reasonable for ScalarPair that avoids the pointer indirection. Cc ```@workingjubilee```
2024-11-20aarch64 softfloat target: always pass floats in int registersRalf Jung-0/+48
2024-11-17Likely unlikely fixJiri Bobek-13/+91
2024-11-14Always inline functions signatures containing `f16` or `f128`Trevor Gross-0/+29
There are a handful of tier 2 and tier 3 targets that cause a LLVM crash or linker error when generating code that contains `f16` or `f128`. The cranelift backend also does not support these types. To work around this, every function in `std` or `core` that contains these types must be marked `#[inline]` in order to avoid sending any code to the backend unless specifically requested. However, this is inconvenient and easy to forget. Introduce a check for these types in the frontend that automatically inlines any function signatures that take or return `f16` or `f128`. Note that this is not a perfect fix because it does not account for the types being passed by reference or as members of aggregate types, but this is sufficient for what is currently needed in the standard library. Fixes: https://github.com/rust-lang/rust/issues/133035 Closes: https://github.com/rust-lang/rust/pull/133037
2024-11-14tests: use `max-llvm-major-version` instead of `ignore-llvm-version` range ↵许杰友 Jieyou Xu (Joe)-3/+3
like `N - 99` For tests that use `ignore-llvm-version: N - M`, replace that with `max-llvm-major-version: N-1`.
2024-11-13Add ``exact-llvm-major-version`` directiveKirill Podoprigora-2/+1
2024-11-12Rollup merge of #132702 - 1c3t3a:issue-132615, r=rcvalleMatthias Krüger-0/+19
CFI: Append debug location to CFI blocks Currently we're not appending debug locations to the inserted CFI blocks. This shows up in #132615 and #100783. This change fixes that by passing down the debug location to the CFI type-test generation and appending it to the blocks. Credits also belong to `@jakos-sec` who worked with me on this.
2024-11-11CFI: Append debug location to CFI blocksBastian Kersting-0/+19
2024-11-10Stabilize Arm64EC inline assemblyTaiki Endo-1/+1
2024-11-09Rollup merge of #131258 - taiki-e:s390x-stabilize-asm, r=AmanieuJubilee-1/+1
Stabilize s390x inline assembly This stabilizes inline assembly for s390x (SystemZ). Corresponding reference PR: https://github.com/rust-lang/reference/pull/1643 --- From the requirements of stabilization mentioned in https://github.com/rust-lang/rust/issues/93335 > Each architecture needs to be reviewed before stabilization: > - It must have clobber_abi. Done in https://github.com/rust-lang/rust/pull/130630. > - It must be possible to clobber every register that is normally clobbered by a function call. Done in the PR that added support for clobber_abi. > - Generally review that the exposed register classes make sense. The followings can be used as input/output: - `reg` (`r[0-10]`, `r[12-14]`): General-purpose register - `reg_addr` (`r[1-10]`, `r[12-14]`): General-purpose register except `r0` which is evaluated as zero in an address context This class is needed because `r0`, which may be allocated when using the `reg` class, cannot be used as a register in certain contexts. This is identical to the `a` constraint in LLVM and GCC. See https://github.com/rust-lang/rust/pull/119431 for details. - `freg` (`f[0-15]`): Floating-point register The followings are clobber-only: - `vreg` (`v[0-31]`): Vector register Technically `vreg` should be able to accept `#[repr(simd)]` types as input/output if the unstable `vector` target feature added is enabled, but `core::arch` has no s390x vector type and both `#[repr(simd)]` and `core::simd` are unstable. Everything related is unstable, so the fact that this is currently a clobber-only should not be considered a stabilization blocker. (https://github.com/rust-lang/rust/issues/130869 tracks unstable stuff here) - `areg` (`a[2-15]`): Access register All of the above register classes except `reg_addr` are needed for `clobber_abi`. The followings cannot be used as operands for inline asm (see also [getReservedRegs](https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/SystemZ/SystemZRegisterInfo.cpp#L258-L282) and [SystemZELFRegisters](https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/SystemZ/SystemZRegisterInfo.h#L107-L128) in LLVM): - `r11`: frame pointer - `r15`: stack pointer - `a0`, `a1`: Reserved for system use - `c[0-15]` (control register) Reserved by the kernel Although not listed in the above requirements, `preserves_flags` is implemented in https://github.com/rust-lang/rust/pull/111331. --- cc ``@uweigand`` r? ``@Amanieu`` ``@rustbot`` label +O-SystemZ +A-inline-assembly
2024-11-09Add discriminators to DILocations when multiple functions are inlined into a ↵Kyle Huey-0/+64
single point. LLVM does not expect to ever see multiple dbg_declares for the same variable at the same location with different values. proc-macros make it possible for arbitrary code, including multiple calls that get inlined, to happen at any given location in the source code. Add discriminators when that happens so these locations are different to LLVM. This may interfere with the AddDiscriminators pass in LLVM, which is added by the unstable flag -Zdebug-info-for-profiling. Fixes #131944
2024-11-09Rollup merge of #132777 - durin42:llvm-20-poison-prop, r=nikicMatthias Krüger-1/+10
try_question_mark_nop: update test for LLVM 20 llvm/llvm-project@dd116369f646d023a2e7e5c145a1bed5dcf9a45c changes the IR of this test in a way that I don't think is bad, but needs adjusting. r? `@nikic` `@rustbot` label: +llvm-main
2024-11-09Rollup merge of #132745 - RalfJung:pointee-info-inside-enum, r=DianQKMatthias Krüger-4/+20
pointee_info_at: fix logic for recursing into enums Fixes https://github.com/rust-lang/rust/issues/131834 The logic in `pointee_info_at` was likely written at a time when the null pointer optimization was the *only* enum layout optimization -- and as `Variant::Multiple` kept getting expanded, nobody noticed that the logic is now unsound. The job of this function is to figure out whether there is a dereferenceable-or-null and aligned pointer at a given offset inside a type. So when we recurse into a multi-variant enum, we better make sure that all the other enum variants must be null! This is the part that was forgotten, and this PR adds it. The reason this didn't explode in many ways so far is that our references only have 1 niche value (null), so it's not possible on stable to have a multi-variant enum with a dereferenceable pointer and other enum variants that are not null. But with `rustc_layout_scalar_valid_range` attributes one can force such a layout, and if `@the8472's` work on alignment niches ever lands, that will make this possible on stable.