Michael Goulet 828a3a41b3 Rollup merge of #137417 - taiki-e:riscv-atomic, r=Amanieu ... rustc_target: Add more RISC-V atomic-related features This is a continuation of https://github.com/rust-lang/rust/pull/130877 and adds a few target features, including `zacas`, which was experimental in LLVM 19 and marked non-experimental in LLVM 20. This adds the following target features to unstable riscv_target_feature: - `za64rs` (Za64rs Extension 1.0): Reservation Set Size of at Most 64 Bytes ([definition in LLVM](https://github.com/llvm/llvm-project/blob/llvmorg-20.1.0-rc2/llvm/lib/Target/RISCV/RISCVFeatures.td#L227-L228), [available since LLVM 18](8649328060)) - `za128rs` (Za128rs Extension 1.0): Reservation Set Size of at Most 128 Bytes ([definition in LLVM](https://github.com/llvm/llvm-project/blob/llvmorg-20.1.0-rc2/llvm/lib/Target/RISCV/RISCVFeatures.td#L230-L231), [available since LLVM 18](8649328060)) - IIUC, `za*rs` can be referenced when implementing helpers to reduce contention in synchronization primitives, like [`crossbeam_utils::CachePadded`](https://docs.rs/crossbeam-utils/latest/crossbeam_utils/struct.CachePadded.html). (relevant discussion: https://github.com/riscv/riscv-profiles/issues/79) - `zacas` (Zacas Extension 1.0): Atomic Compare-And-Swap Instructions (`amocas.{w,d,q}{,.aq,.rl,.aqrl}` and `amocas.{b,h}{,.aq,.rl,.aqrl}` when `zabha` is also enabled) ([definition in LLVM](https://github.com/llvm/llvm-project/blob/llvmorg-20.1.0-rc2/llvm/lib/Target/RISCV/RISCVFeatures.td#L240-L243), [available as non-experimental since LLVM 20](614aeda93b)) - This implies `zaamo`. - This is used to optimize CAS in existing atomics and/or implement 64-bit/128-bit atomics on riscv32/riscv64 (e.g., https://github.com/taiki-e/portable-atomic/pull/173). - Note that [LLVM does not automatically use this instruction for 64-bit/128-bit atomics on riscv32/riscv64 even if this feature is enabled, because doing it changes the ABI](876174ffd7/llvm/docs/RISCVUsage.rst (riscv-zacas-note)). (If the ability to do that is provided by LLVM in the future, it should probably be controlled by another ABI feature similar to `forced-atomics`.) - `zama16b` (Zama16b Extension 1.0): Atomic 16-byte misaligned loads, stores and AMOs ([definition in LLVM](https://github.com/llvm/llvm-project/blob/llvmorg-20.1.0-rc2/llvm/lib/Target/RISCV/RISCVFeatures.td#L255-L256), [available since LLVM 19](b090569685)) - IIUC, unlike AArch64 FEAT_LSE2 which also makes 16-byte aligned ldp ({i,u}128 load) atomic, this extension only affects instructions that already considered atomic if they were naturally aligned. i.e., fld (f64 load) on riscv32 would not be atomic with or without this extension ([relevant QEMU code](b69801dd6b/target/riscv/insn_trans/trans_rvd.c.inc (L50-L62))). - `zawrs` (Zawrs Extension 1.0): Wait on Reservation Set (`wrs.nto` and `wrs.sto`) ([definition in LLVM](https://github.com/llvm/llvm-project/blob/llvmorg-20.1.0-rc2/llvm/lib/Target/RISCV/RISCVFeatures.td#L258), [available as non-experimental since LLVM 17](d41a73aa94)) - This is used to optimize synchronization primitives (e.g., Linux uses this for spinlocks (b8ddb0df30)). Btw, the question of whether `zaamo` is implied by `zabha` or not, which was discussed in https://github.com/rust-lang/rust/pull/130877, has been resolved in LLVM 20, since LLVM now treats `zaamo` as implied by `zabha`/`zacas` (https://github.com/llvm/llvm-project/pull/115694), just like GCC and rustc. r? `@Amanieu` `@rustbot` label +O-riscv +A-target-feature		2025-02-24 19:21:47 -05:00
..
rustc	Fix overcapturing, unsafe extern blocks, and new unsafe ops	2025-02-22 00:01:48 +00:00
rustc_abi	Rollup merge of #137334 - compiler-errors:edition-2024-fresh-2, r=saethlin,traviscross	2025-02-23 02:44:18 -05:00
rustc_arena	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_ast	Auto merge of #137420 - matthiaskrgr:rollup-rr0q37f, r=matthiaskrgr	2025-02-22 13:32:44 +00:00
rustc_ast_ir	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_ast_lowering	Rollup merge of #137334 - compiler-errors:edition-2024-fresh-2, r=saethlin,traviscross	2025-02-23 02:44:18 -05:00
rustc_ast_passes	Rollup merge of #137435 - estebank:match-arm-2, r=compiler-errors	2025-02-23 02:44:19 -05:00
rustc_ast_pretty	Rollup merge of #137423 - Urgau:imprv-pretty-hir, r=compiler-errors	2025-02-23 02:44:19 -05:00
rustc_attr_data_structures	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_attr_parsing	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_baked_icu_data	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_borrowck	Rollup merge of #137334 - compiler-errors:edition-2024-fresh-2, r=saethlin,traviscross	2025-02-23 02:44:18 -05:00
rustc_builtin_macros	Rollup merge of #135501 - tgross35:stdlib-dependencies-private, r=bjorn3	2025-02-23 00:16:18 +01:00
rustc_codegen_cranelift	Rollup merge of #137505 - tgross35:builtins-cannot-call-error, r=compiler-errors	2025-02-24 02:11:38 -05:00
rustc_codegen_gcc	Rollup merge of #136543 - RalfJung:round-ties-even, r=tgross35	2025-02-23 14:30:25 -05:00
rustc_codegen_llvm	Rollup merge of #137417 - taiki-e:riscv-atomic, r=Amanieu	2025-02-24 19:21:47 -05:00
rustc_codegen_ssa	Rollup merge of #137505 - tgross35:builtins-cannot-call-error, r=compiler-errors	2025-02-24 02:11:38 -05:00
rustc_const_eval	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_data_structures	Rollup merge of #136610 - Jarcho:range_idx, r=Noratrieb	2025-02-24 02:11:32 -05:00
rustc_driver	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_driver_impl	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_error_codes	Consolidate and rework CoercePointee and DispatchFromDyn errors	2025-02-24 19:34:54 +00:00
rustc_error_messages	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_errors	Rollup merge of #137333 - compiler-errors:edition-2024-fresh, r=Nadrieril	2025-02-22 11:36:43 +01:00
rustc_expand	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_feature	Remove dyn_compatible_for_dispatch	2025-02-24 18:48:40 +00:00
rustc_fluent_macro	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_fs_util	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_graphviz	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_hashes	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_hir	Rollup merge of #137334 - compiler-errors:edition-2024-fresh-2, r=saethlin,traviscross	2025-02-23 02:44:18 -05:00
rustc_hir_analysis	Rollup merge of #137289 - compiler-errors:coerce-unsized-errors, r=oli-obk	2025-02-24 19:21:45 -05:00
rustc_hir_pretty	Rollup merge of #137423 - Urgau:imprv-pretty-hir, r=compiler-errors	2025-02-23 02:44:19 -05:00
rustc_hir_typeck	Rollup merge of #136610 - Jarcho:range_idx, r=Noratrieb	2025-02-24 02:11:32 -05:00
rustc_incremental	Rollup merge of #137180 - compiler-errors:sym-regions, r=oli-obk	2025-02-23 00:16:19 +01:00
rustc_index	Rollup merge of #136610 - Jarcho:range_idx, r=Noratrieb	2025-02-24 02:11:32 -05:00
rustc_index_macros	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_infer	Rollup merge of #136610 - Jarcho:range_idx, r=Noratrieb	2025-02-24 02:11:32 -05:00
rustc_interface	Auto merge of #137420 - matthiaskrgr:rollup-rr0q37f, r=matthiaskrgr	2025-02-22 13:32:44 +00:00
rustc_lexer	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_lint	Auto merge of #137237 - cuviper:stage0, r=Mark-Simulacrum	2025-02-23 11:12:56 +00:00
rustc_lint_defs	Fix binding mode problems	2025-02-22 00:13:19 +00:00
rustc_llvm	Auto merge of #137271 - nikic:gep-nuw-2, r=scottmcm	2025-02-24 03:06:16 +00:00
rustc_log	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_macros	Fix binding mode problems	2025-02-22 00:13:19 +00:00
rustc_metadata	Rollup merge of #137334 - compiler-errors:edition-2024-fresh-2, r=saethlin,traviscross	2025-02-23 02:44:18 -05:00
rustc_middle	Fix some use items that import more than necessary.	2025-02-24 09:30:42 +11:00
rustc_mir_build	Fix some use items that import more than necessary.	2025-02-24 09:30:42 +11:00
rustc_mir_dataflow	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_mir_transform	Rollup merge of #136610 - Jarcho:range_idx, r=Noratrieb	2025-02-24 02:11:32 -05:00
rustc_monomorphize	Auto merge of #137225 - RalfJung:vectorcall, r=nnethercote	2025-02-23 14:12:38 +00:00
rustc_next_trait_solver	Rollup merge of #137333 - compiler-errors:edition-2024-fresh, r=Nadrieril	2025-02-22 11:36:43 +01:00
rustc_parse	Rollup merge of #137435 - estebank:match-arm-2, r=compiler-errors	2025-02-23 02:44:19 -05:00
rustc_parse_format	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_passes	Rollup merge of #137180 - compiler-errors:sym-regions, r=oli-obk	2025-02-23 00:16:19 +01:00
rustc_pattern_analysis	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_privacy	Rollup merge of #137180 - compiler-errors:sym-regions, r=oli-obk	2025-02-23 00:16:19 +01:00
rustc_query_impl	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_query_system	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_resolve	Fix binding mode problems	2025-02-22 00:13:19 +00:00
rustc_sanitizers	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_serialize	rename sub_ptr 😅	2025-02-23 23:11:00 +07:00
rustc_session	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_smir	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_span	Rollup merge of #136543 - RalfJung:round-ties-even, r=tgross35	2025-02-23 14:30:25 -05:00
rustc_symbol_mangling	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_target	Rollup merge of #137417 - taiki-e:riscv-atomic, r=Amanieu	2025-02-24 19:21:47 -05:00
rustc_trait_selection	Remove dyn_compatible_for_dispatch	2025-02-24 18:48:40 +00:00
rustc_traits	Rollup merge of #137333 - compiler-errors:edition-2024-fresh, r=Nadrieril	2025-02-22 11:36:43 +01:00
rustc_transmute	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
rustc_ty_utils	Rollup merge of #137334 - compiler-errors:edition-2024-fresh-2, r=saethlin,traviscross	2025-02-23 02:44:18 -05:00
rustc_type_ir	Greatly simplify lifetime captures in edition 2024	2025-02-22 22:24:52 +00:00
rustc_type_ir_macros	Upgrade the compiler to edition 2024	2025-02-22 00:01:48 +00:00
stable_mir	Rollup merge of #137448 - compiler-errors:control-flow-oops, r=scottmcm	2025-02-23 02:44:20 -05:00