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Stabilize 28 RISC-V target features (riscv_ratified_v2)
This commit stabilizes RISC-V target features with following constraints: * Describes a ratified extension. * Implemented on Rust 1.88.0 or before. Waiting for three+ version cycles seems sufficient. * Does not disrupt current rustc's target feature + ABI handling. It excludes "E" and all floating point-arithmetic extensions. "Zfinx" family does not involve floating point registers but not stabilizing for now to avoid possible confusion between the "F" extension family. * Not vector-related (floating point and integer). While integer vector subset should not cause any ABI issues (as we don't use ABI-dependent floating point registers), we need to discuss before stabilizing them. * Supported by the lowest LLVM version supported by rustc. It excludes the "Zacas" extension, newly supported in LLVM 20 (while the minimum LLVM version supported by rustc is 19). List of target features to be stabilized: 1. "b" 2. "za64rs" (no-RT) 3. "za128rs" (no-RT) 4. "zaamo" 5. "zabha" 6. "zalrsc" 7. "zama16b" (no-RT) 8. "zawrs" 9. "zca" 10. "zcb" 11. "zcmop" 12. "zic64b" (no-RT) 13. "zicbom" 14. "zicbop" (no-RT) 15. "zicboz" 16. "ziccamoa" (no-RT) 17. "ziccif" (no-RT) 18. "zicclsm" (no-RT) 19. "ziccrse" (no-RT) 20. "zicntr" 21. "zicond" 22. "zicsr" 23. "zifencei" 24. "zihintntl" 25. "zihintpause" 26. "zihpm" 27. "zimop" 28. "ztso" Of which, 19 of them (28 minus 9 "no-RT" target features) support runtime detection through `std::arch::is_riscv_feature_detected!()`.
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‎compiler/rustc_codegen_ssa/src/back/metadata.rs

Lines changed: 2 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -330,14 +330,12 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 {
330330
let mut e_flags: u32 = 0x0;
331331

332332
// Check if compression is enabled
333-
// `unstable_target_features` is used here because "zca" is gated behind riscv_target_feature.
334-
if sess.unstable_target_features.contains(&sym::zca) {
333+
if sess.target_features.contains(&sym::zca) {
335334
e_flags |= elf::EF_RISCV_RVC;
336335
}
337336

338337
// Check if RVTSO is enabled
339-
// `unstable_target_features` is used here because "ztso" is gated behind riscv_target_feature.
340-
if sess.unstable_target_features.contains(&sym::ztso) {
338+
if sess.target_features.contains(&sym::ztso) {
341339
e_flags |= elf::EF_RISCV_TSO;
342340
}
343341

‎compiler/rustc_target/src/target_features.rs

Lines changed: 28 additions & 28 deletions
Original file line numberDiff line numberDiff line change
@@ -589,7 +589,7 @@ const NVPTX_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
589589
static RISCV_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
590590
// tidy-alphabetical-start
591591
("a", Stable, &["zaamo", "zalrsc"]),
592-
("b", Unstable(sym::riscv_target_feature), &["zba", "zbb", "zbs"]),
592+
("b", Stable, &["zba", "zbb", "zbs"]),
593593
("c", Stable, &["zca"]),
594594
("d", Unstable(sym::riscv_target_feature), &["f"]),
595595
("e", Unstable(sym::riscv_target_feature), &[]),
@@ -647,24 +647,24 @@ static RISCV_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
647647
("unaligned-scalar-mem", Unstable(sym::riscv_target_feature), &[]),
648648
("unaligned-vector-mem", Unstable(sym::riscv_target_feature), &[]),
649649
("v", Unstable(sym::riscv_target_feature), &["zvl128b", "zve64d"]),
650-
("za64rs", Unstable(sym::riscv_target_feature), &["za128rs"]), // Za64rs ⊃ Za128rs
651-
("za128rs", Unstable(sym::riscv_target_feature), &[]),
652-
("zaamo", Unstable(sym::riscv_target_feature), &[]),
653-
("zabha", Unstable(sym::riscv_target_feature), &["zaamo"]),
650+
("za64rs", Stable, &["za128rs"]), // Za64rs ⊃ Za128rs
651+
("za128rs", Stable, &[]),
652+
("zaamo", Stable, &[]),
653+
("zabha", Stable, &["zaamo"]),
654654
("zacas", Unstable(sym::riscv_target_feature), &["zaamo"]),
655-
("zalrsc", Unstable(sym::riscv_target_feature), &[]),
656-
("zama16b", Unstable(sym::riscv_target_feature), &[]),
657-
("zawrs", Unstable(sym::riscv_target_feature), &[]),
655+
("zalrsc", Stable, &[]),
656+
("zama16b", Stable, &[]),
657+
("zawrs", Stable, &[]),
658658
("zba", Stable, &[]),
659659
("zbb", Stable, &[]),
660660
("zbc", Stable, &["zbkc"]), // Zbc ⊃ Zbkc
661661
("zbkb", Stable, &[]),
662662
("zbkc", Stable, &[]),
663663
("zbkx", Stable, &[]),
664664
("zbs", Stable, &[]),
665-
("zca", Unstable(sym::riscv_target_feature), &[]),
666-
("zcb", Unstable(sym::riscv_target_feature), &["zca"]),
667-
("zcmop", Unstable(sym::riscv_target_feature), &["zca"]),
665+
("zca", Stable, &[]),
666+
("zcb", Stable, &["zca"]),
667+
("zcmop", Stable, &["zca"]),
668668
("zdinx", Unstable(sym::riscv_target_feature), &["zfinx"]),
669669
("zfa", Unstable(sym::riscv_target_feature), &["f"]),
670670
("zfbfmin", Unstable(sym::riscv_target_feature), &["f"]), // and a subset of Zfhmin
@@ -673,22 +673,22 @@ static RISCV_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
673673
("zfinx", Unstable(sym::riscv_target_feature), &["zicsr"]),
674674
("zhinx", Unstable(sym::riscv_target_feature), &["zhinxmin"]),
675675
("zhinxmin", Unstable(sym::riscv_target_feature), &["zfinx"]),
676-
("zic64b", Unstable(sym::riscv_target_feature), &[]),
677-
("zicbom", Unstable(sym::riscv_target_feature), &[]),
678-
("zicbop", Unstable(sym::riscv_target_feature), &[]),
679-
("zicboz", Unstable(sym::riscv_target_feature), &[]),
680-
("ziccamoa", Unstable(sym::riscv_target_feature), &[]),
681-
("ziccif", Unstable(sym::riscv_target_feature), &[]),
682-
("zicclsm", Unstable(sym::riscv_target_feature), &[]),
683-
("ziccrse", Unstable(sym::riscv_target_feature), &[]),
684-
("zicntr", Unstable(sym::riscv_target_feature), &["zicsr"]),
685-
("zicond", Unstable(sym::riscv_target_feature), &[]),
686-
("zicsr", Unstable(sym::riscv_target_feature), &[]),
687-
("zifencei", Unstable(sym::riscv_target_feature), &[]),
688-
("zihintntl", Unstable(sym::riscv_target_feature), &[]),
689-
("zihintpause", Unstable(sym::riscv_target_feature), &[]),
690-
("zihpm", Unstable(sym::riscv_target_feature), &["zicsr"]),
691-
("zimop", Unstable(sym::riscv_target_feature), &[]),
676+
("zic64b", Stable, &[]),
677+
("zicbom", Stable, &[]),
678+
("zicbop", Stable, &[]),
679+
("zicboz", Stable, &[]),
680+
("ziccamoa", Stable, &[]),
681+
("ziccif", Stable, &[]),
682+
("zicclsm", Stable, &[]),
683+
("ziccrse", Stable, &[]),
684+
("zicntr", Stable, &["zicsr"]),
685+
("zicond", Stable, &[]),
686+
("zicsr", Stable, &[]),
687+
("zifencei", Stable, &[]),
688+
("zihintntl", Stable, &[]),
689+
("zihintpause", Stable, &[]),
690+
("zihpm", Stable, &["zicsr"]),
691+
("zimop", Stable, &[]),
692692
("zk", Stable, &["zkn", "zkr", "zkt"]),
693693
("zkn", Stable, &["zbkb", "zbkc", "zbkx", "zkne", "zknd", "zknh"]),
694694
("zknd", Stable, &[]),
@@ -699,7 +699,7 @@ static RISCV_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
699699
("zksed", Stable, &[]),
700700
("zksh", Stable, &[]),
701701
("zkt", Stable, &[]),
702-
("ztso", Unstable(sym::riscv_target_feature), &[]),
702+
("ztso", Stable, &[]),
703703
("zvbb", Unstable(sym::riscv_target_feature), &["zvkb"]), // Zvbb ⊃ Zvkb
704704
("zvbc", Unstable(sym::riscv_target_feature), &["zve64x"]),
705705
("zve32f", Unstable(sym::riscv_target_feature), &["zve32x", "f"]),

‎library/std_detect/src/detect/arch/riscv.rs

Lines changed: 19 additions & 19 deletions
Original file line numberDiff line numberDiff line change
@@ -194,47 +194,47 @@ features! {
194194
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] unaligned_vector_mem: "unaligned-vector-mem";
195195
/// Has reasonably performant unaligned vector
196196
197-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zicsr: "zicsr";
197+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zicsr: "zicsr";
198198
/// "Zicsr" Extension for Control and Status Register (CSR) Instructions
199-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zicntr: "zicntr";
199+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zicntr: "zicntr";
200200
/// "Zicntr" Extension for Base Counters and Timers
201-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zihpm: "zihpm";
201+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zihpm: "zihpm";
202202
/// "Zihpm" Extension for Hardware Performance Counters
203-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zifencei: "zifencei";
203+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zifencei: "zifencei";
204204
/// "Zifencei" Extension for Instruction-Fetch Fence
205205
206-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zihintntl: "zihintntl";
206+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zihintntl: "zihintntl";
207207
/// "Zihintntl" Extension for Non-Temporal Locality Hints
208-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zihintpause: "zihintpause";
208+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zihintpause: "zihintpause";
209209
/// "Zihintpause" Extension for Pause Hint
210-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zimop: "zimop";
210+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zimop: "zimop";
211211
/// "Zimop" Extension for May-Be-Operations
212-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zicbom: "zicbom";
212+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zicbom: "zicbom";
213213
/// "Zicbom" Extension for Cache-Block Management Instructions
214-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zicboz: "zicboz";
214+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zicboz: "zicboz";
215215
/// "Zicboz" Extension for Cache-Block Zero Instruction
216-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zicond: "zicond";
216+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zicond: "zicond";
217217
/// "Zicond" Extension for Integer Conditional Operations
218218
219219
@FEATURE: #[stable(feature = "riscv_ratified", since = "1.78.0")] m: "m";
220220
/// "M" Extension for Integer Multiplication and Division
221221
222222
@FEATURE: #[stable(feature = "riscv_ratified", since = "1.78.0")] a: "a";
223223
/// "A" Extension for Atomic Instructions
224-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zalrsc: "zalrsc";
224+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zalrsc: "zalrsc";
225225
/// "Zalrsc" Extension for Load-Reserved/Store-Conditional Instructions
226-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zaamo: "zaamo";
226+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zaamo: "zaamo";
227227
/// "Zaamo" Extension for Atomic Memory Operations
228-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zawrs: "zawrs";
228+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zawrs: "zawrs";
229229
/// "Zawrs" Extension for Wait-on-Reservation-Set Instructions
230-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zabha: "zabha";
230+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zabha: "zabha";
231231
/// "Zabha" Extension for Byte and Halfword Atomic Memory Operations
232232
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zacas: "zacas";
233233
/// "Zacas" Extension for Atomic Compare-and-Swap (CAS) Instructions
234234
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zam: "zam";
235235
without cfg check: true;
236236
/// "Zam" Extension for Misaligned Atomics
237-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] ztso: "ztso";
237+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] ztso: "ztso";
238238
/// "Ztso" Extension for Total Store Ordering
239239
240240
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] f: "f";
@@ -264,20 +264,20 @@ features! {
264264
265265
@FEATURE: #[stable(feature = "riscv_ratified", since = "1.78.0")] c: "c";
266266
/// "C" Extension for Compressed Instructions
267-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zca: "zca";
267+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zca: "zca";
268268
/// "Zca" Compressed Instructions excluding Floating-Point Loads/Stores
269269
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zcf: "zcf";
270270
without cfg check: true;
271271
/// "Zcf" Compressed Instructions for Single-Precision Floating-Point Loads/Stores on RV32
272272
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zcd: "zcd";
273273
without cfg check: true;
274274
/// "Zcd" Compressed Instructions for Double-Precision Floating-Point Loads/Stores
275-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zcb: "zcb";
275+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zcb: "zcb";
276276
/// "Zcb" Simple Code-size Saving Compressed Instructions
277-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] zcmop: "zcmop";
277+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] zcmop: "zcmop";
278278
/// "Zcmop" Extension for Compressed May-Be-Operations
279279
280-
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] b: "b";
280+
@FEATURE: #[stable(feature = "riscv_ratified_v2", since = "CURRENT_RUSTC_VERSION")] b: "b";
281281
/// "B" Extension for Bit Manipulation
282282
@FEATURE: #[stable(feature = "riscv_ratified", since = "1.78.0")] zba: "zba";
283283
/// "Zba" Extension for Address Generation

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