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| author | Jubilee <workingjubilee@gmail.com> | 2024-10-21 20:32:00 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-10-21 20:32:00 -0700 |
| commit | fe2cbbd2d571965d30c6f25c6d865babf4529e85 (patch) | |
| tree | 926b21e859f7da2cb1236dabe70dea166c8f481c /src/doc | |
| parent | 814df6e50eaf89b90793e7d9618bb60f1f18377a (diff) | |
| parent | 37dc4ec8d6519d7ba1ed8a11fb57ff4d1eb995dd (diff) | |
Rollup merge of #130432 - azhogin:azhogin/regparm, r=workingjubilee,pnkfelix
rust_for_linux: -Zregparm=<N> commandline flag for X86 (#116972) Command line flag `-Zregparm=<N>` for X86 (32-bit) for rust-for-linux: https://github.com/rust-lang/rust/issues/116972 Implemented in the similar way as fastcall/vectorcall support (args are marked InReg if fit).
Diffstat (limited to 'src/doc')
| -rw-r--r-- | src/doc/unstable-book/src/compiler-flags/regparm.md | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/doc/unstable-book/src/compiler-flags/regparm.md b/src/doc/unstable-book/src/compiler-flags/regparm.md new file mode 100644 index 00000000000..8f311f091c0 --- /dev/null +++ b/src/doc/unstable-book/src/compiler-flags/regparm.md @@ -0,0 +1,20 @@ +# `regparm` + +The tracking issue for this feature is: https://github.com/rust-lang/rust/issues/131749. + +------------------------ + +Option -Zregparm=N causes the compiler to pass N arguments +in registers EAX, EDX, and ECX instead of on the stack for "C", "cdecl", and "stdcall" fn. +It is UNSOUND to link together crates that use different values for this flag. +It is only supported on `x86`. + +It is equivalent to [Clang]'s and [GCC]'s `-mregparm`. + +Supported values for this option are 0-3. + +[Clang]: https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-mregparm +[GCC]: https://gcc.gnu.org/onlinedocs/gcc/x86-Function-Attributes.html#index-regparm-function-attribute_002c-x86 + +Implementation details: +For eligible arguments, llvm `inreg` attribute is set. |