std_detect: RISC-V platform guide documentation #145417
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This is practically a revert of a revert, making the commit e907456b2e10622ccd854a3bba8d02ce170b5dbb on `stdarch` come around again with minor fixes, enhancements and adjustments. An excerpt from the original commit message follows: Since there's no architectural feature detection on RISC-V (unlike `CPUID` on x86 architectures and some system registers on Arm/AArch64), runtime feature detection entirely depends on the platform-specific facility. As a result, availability of each feature heavily depends on the platform and its version. To help users make a decision for feature checking on a RISC-V system, this commit adds a platform guide with minimum supported platform versions.
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Rollup of 13 pull requests Successful merges: - #139357 (Fix parameter order for `_by()` variants of `min` / `max`/ `minmax` in `std::cmp`) - #140314 (Rustdoc: typecheck scrape-examples.js) - #140794 (mention lint group in default level lint note) - #145006 (Clarify EOF handling for `BufRead::skip_until`) - #145252 (Demote x86_64-apple-darwin to Tier 2 with host tools) - #145359 (Fix bug where `rustdoc-js` tester would not pick the right `search.js` file if there is more than one) - #145381 (Implement feature `int_lowest_highest_one` for integer and NonZero types) - #145417 (std_detect: RISC-V platform guide documentation) - #145531 (Add runtime detection for APX-F and AVX10) - #145619 (`std_detect`: Use `rustc-std-workspace-*` to pull in `compiler-builtins`) - #145622 (Remove the std workspace patch for `compiler-builtins`) - #145623 (Pretty print the name of an future from calling async closure) - #145626 (add a fallback implementation for the `prefetch_*` intrinsics ) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of #145417 - a4lg:riscv-arch-platform-guide-ch2, r=Amanieu std_detect: RISC-V platform guide documentation This is practically a revert of a revert, making the commit e907456b2e10622ccd854a3bba8d02ce170b5dbb on `stdarch` come around again with minor fixes, enhancements and adjustments. An excerpt from the original commit message follows: Since there's no architectural feature detection on RISC-V (unlike `CPUID` on x86 architectures and some system registers on Arm/AArch64), runtime feature detection entirely depends on the platform-specific facility. As a result, availability of each feature heavily depends on the platform and its version. To help users make a decision for feature checking on a RISC-V system, this commit adds a platform guide with minimum supported platform versions.
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Rollup of 13 pull requests Successful merges: - rust-lang/rust#139357 (Fix parameter order for `_by()` variants of `min` / `max`/ `minmax` in `std::cmp`) - rust-lang/rust#140314 (Rustdoc: typecheck scrape-examples.js) - rust-lang/rust#140794 (mention lint group in default level lint note) - rust-lang/rust#145006 (Clarify EOF handling for `BufRead::skip_until`) - rust-lang/rust#145252 (Demote x86_64-apple-darwin to Tier 2 with host tools) - rust-lang/rust#145359 (Fix bug where `rustdoc-js` tester would not pick the right `search.js` file if there is more than one) - rust-lang/rust#145381 (Implement feature `int_lowest_highest_one` for integer and NonZero types) - rust-lang/rust#145417 (std_detect: RISC-V platform guide documentation) - rust-lang/rust#145531 (Add runtime detection for APX-F and AVX10) - rust-lang/rust#145619 (`std_detect`: Use `rustc-std-workspace-*` to pull in `compiler-builtins`) - rust-lang/rust#145622 (Remove the std workspace patch for `compiler-builtins`) - rust-lang/rust#145623 (Pretty print the name of an future from calling async closure) - rust-lang/rust#145626 (add a fallback implementation for the `prefetch_*` intrinsics ) r? `@ghost` `@rustbot` modify labels: rollup
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…, r=Amanieu std_detect: RISC-V platform guide documentation This is practically a revert of a revert, making the commit e907456b2e10622ccd854a3bba8d02ce170b5dbb on `stdarch` come around again with minor fixes, enhancements and adjustments. An excerpt from the original commit message follows: Since there's no architectural feature detection on RISC-V (unlike `CPUID` on x86 architectures and some system registers on Arm/AArch64), runtime feature detection entirely depends on the platform-specific facility. As a result, availability of each feature heavily depends on the platform and its version. To help users make a decision for feature checking on a RISC-V system, this commit adds a platform guide with minimum supported platform versions.
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This is practically a revert of a revert, making the commit e907456b2e10622ccd854a3bba8d02ce170b5dbb on
stdarchcome around again with minor fixes, enhancements and adjustments.An excerpt from the original commit message follows:
Since there's no architectural feature detection on RISC-V (unlike
CPUIDon x86 architectures and some system registers on Arm/AArch64), runtime feature detection entirely depends on the platform-specific facility.As a result, availability of each feature heavily depends on the platform and its version.
To help users make a decision for feature checking on a RISC-V system, this commit adds a platform guide with minimum supported platform versions.
History
This is originally rust-lang/stdarch#1779 which is approved and an attempt to merge this was performed... but blocked by HTML errors (generated by rustdoc) later fixed by #140434 (cf. #140389; so at that time I reverted the original PR as rust-lang/stdarch#1792 and non-table parts are partially restored as rust-lang/stdarch#1797).
Since #140434 is merged now and the
std_detectcrate is now under the main Rust repository, I'm going to fully restore the intent of rust-lang/stdarch#1779 (to provide useful yet complex information forstd::arch::is_riscv_feature_detected!users).Changes from the Original (rust-lang/stdarch#1779)
Zcbextension stdarch#1789 (remove footnote from the Zcb extension).linux-riscvML brought the conclusion that the Zicntr extension is included in the base IMA behavior.Note (CI)
I don't have full knowledge about Rust's CI process and we may need to wait for the next beta bump.
r? @Amanieu
@rustbot label +O-riscv