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ojeda opened this issue Oct 20, 2023 · 3 comments
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-Zregparm=3 support in rustc #116972

ojeda opened this issue Oct 20, 2023 · 3 comments
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A-ABI Area: Concerning the application binary interface (ABI) C-feature-request Category: A feature request, i.e: not implemented / a PR. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@ojeda
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ojeda commented Oct 20, 2023 •
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i.e. the equivalent of Clang's/GCC's -mregparm=3. The kernel needs it to support the x86 32-bit architecture, together with -Zreg-struct-return.

It could potentially be a "global target feature", i.e. a target feature that is required to be set the same way for all compilation units.

https://gcc.gnu.org/onlinedocs/gcc/x86-Function-Attributes.html#index-regparm-function-attribute_002c-x86
https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-mregparm
@rustbot rustbot added the needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. label Oct 20, 2023
@ojeda ojeda mentioned this issue Oct 20, 2023
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@bjorn3 bjorn3 added the A-ABI Area: Concerning the application binary interface (ABI) label Oct 20, 2023
@Noratrieb Noratrieb added T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. C-feature-request Category: A feature request, i.e: not implemented / a PR. and removed needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. labels Oct 21, 2023
@ojeda ojeda mentioned this issue Apr 2, 2024
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intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Jun 4, 2024
@sulix @intel-lab-lkp
arch: um: rust: Add i386 support for Rust
366c4bd 
At present, Rust in the kernel only supports 64-bit x86, so UML has
followed suit. However, it's significantly easier to support 32-bit i386
on UML than on bare metal, as UML does not use the -mregparm option
(which alters the ABI), which is not yet supported by rustc[1].

Add support for CONFIG_RUST on um/i386, by adding a new target config to
generate_rust_target, and replacing various checks on CONFIG_X86_64 to
also support CONFIG_X86_32.

We still use generate_rust_target, rather than a built-in rustc target,
in order to match x86_64, provide a future place for -mregparm, and more
easily disable floating point instructions.

With these changes, the KUnit tests pass with:
kunit.py run --make_options LLVM=1 --kconfig_add CONFIG_RUST=y
--kconfig_add CONFIG_64BIT=n --kconfig_add CONFIG_FORTIFY_SOURCE=n

An earlier version of these changes was proposed on the Rust-for-Linux
github[2].

[1]: rust-lang/rust#116972
[2]: Rust-for-Linux#966

Signed-off-by: David Gow <davidgow@google.com>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Jul 5, 2024
@sulix @jmberg-intel
arch: um: rust: Add i386 support for Rust
ab0f4ce 
At present, Rust in the kernel only supports 64-bit x86, so UML has
followed suit. However, it's significantly easier to support 32-bit i386
on UML than on bare metal, as UML does not use the -mregparm option
(which alters the ABI), which is not yet supported by rustc[1].

Add support for CONFIG_RUST on um/i386, by adding a new target config to
generate_rust_target, and replacing various checks on CONFIG_X86_64 to
also support CONFIG_X86_32.

We still use generate_rust_target, rather than a built-in rustc target,
in order to match x86_64, provide a future place for -mregparm, and more
easily disable floating point instructions.

With these changes, the KUnit tests pass with:
kunit.py run --make_options LLVM=1 --kconfig_add CONFIG_RUST=y
--kconfig_add CONFIG_64BIT=n --kconfig_add CONFIG_FORTIFY_SOURCE=n

An earlier version of these changes was proposed on the Rust-for-Linux
github[2].

[1]: rust-lang/rust#116972
[2]: Rust-for-Linux#966

Signed-off-by: David Gow <davidgow@google.com>
Link: https://patch.msgid.link/20240604224052.3138504-1-davidgow@google.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
@Darksonn Darksonn mentioned this issue Sep 3, 2024
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azhogin added a commit to azhogin/rust that referenced this issue Sep 16, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
bb7d64f 
)
@azhogin azhogin mentioned this issue Sep 16, 2024
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azhogin added a commit to azhogin/rust that referenced this issue Sep 16, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
cfed516 
)
azhogin added a commit to azhogin/rust that referenced this issue Sep 16, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
d93f345 
)
azhogin added a commit to azhogin/rust that referenced this issue Sep 16, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
c937a70 
)
azhogin added a commit to azhogin/rust that referenced this issue Sep 16, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
659c7cc 
)
azhogin added a commit to azhogin/rust that referenced this issue Sep 16, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
c2813de 
)
azhogin added a commit to azhogin/rust that referenced this issue Sep 17, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
d6a6c57 
)
@RalfJung
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It could potentially be a #121970 (comment), i.e. a target feature that is required to be set the same way for all compilation units.

Indeed, something like this has to be done for stabilization -- we have to make sure we detect linking crates that use different values for this flag.

(Also, that means without stable -Zbuild-std, this can't actually be used on stable.)

azhogin added a commit to azhogin/rust that referenced this issue Sep 17, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
caecc18 
)
@vincenzopalazzo
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Indeed, something like this has to be done for stabilization -- we have to make sure we detect linking crates that use different values for this flag.

Thanks @RalfJung and yes I think we can go through a stabilization process, I have some draft code for just llvm here vincenzopalazzo@84945fd

azhogin added a commit to azhogin/rust that referenced this issue Oct 2, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
dff5a6d 
)
azhogin added a commit to azhogin/rust that referenced this issue Oct 3, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
d75699c 
)
azhogin added a commit to azhogin/rust that referenced this issue Oct 13, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
0a81b75 
)
azhogin added a commit to azhogin/rust that referenced this issue Oct 14, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
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@azhogin azhogin mentioned this issue Oct 15, 2024
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azhogin added a commit to azhogin/rust that referenced this issue Oct 15, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
92d90fa 
)
azhogin added a commit to azhogin/rust that referenced this issue Oct 17, 2024
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
b3ae64d 
)
fmease added a commit to fmease/rust that referenced this issue Oct 22, 2024
@fmease
Rollup merge of rust-lang#130432 - azhogin:azhogin/regparm, r=working…
2166d75 
…jubilee,pnkfelix

rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972)

Command line flag `-Zregparm=<N>` for X86 (32-bit) for rust-for-linux: rust-lang#116972
Implemented in the similar way as fastcall/vectorcall support (args are marked InReg if fit).
@fmease fmease mentioned this issue Oct 22, 2024
Closed
bors added a commit to rust-lang-ci/rust that referenced this issue Oct 22, 2024
@bors
Auto merge of rust-lang#132018 - fmease:rollup-0sbaxce, r=fmease
f3626a3 
Rollup of 6 pull requests

Successful merges:

 - rust-lang#129935 (make unsupported_calling_conventions a hard error)
 - rust-lang#130432 (rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972))
 - rust-lang#131697 (`rt::Argument`: elide lifetimes)
 - rust-lang#131954 (shave 150ms off bootstrap)
 - rust-lang#131982 (Represent `hir::TraitBoundModifiers` as distinct parts in HIR)
 - rust-lang#132017 (Update triagebot.toml)

r? `@ghost`
`@rustbot` modify labels: rollup
workingjubilee added a commit to workingjubilee/rustc that referenced this issue Oct 22, 2024
@workingjubilee
Rollup merge of rust-lang#130432 - azhogin:azhogin/regparm, r=working…
fe2cbbd 
…jubilee,pnkfelix

rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972)

Command line flag `-Zregparm=<N>` for X86 (32-bit) for rust-for-linux: rust-lang#116972
Implemented in the similar way as fastcall/vectorcall support (args are marked InReg if fit).
@workingjubilee workingjubilee mentioned this issue Oct 22, 2024
Merged
bors added a commit to rust-lang-ci/rust that referenced this issue Oct 22, 2024
@bors
Auto merge of rust-lang#132020 - workingjubilee:rollup-a8iehqg, r=wor…
f225713 
…kingjubilee

Rollup of 6 pull requests

Successful merges:

 - rust-lang#130432 (rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972))
 - rust-lang#131697 (`rt::Argument`: elide lifetimes)
 - rust-lang#131807 (Always specify `llvm_abiname` for RISC-V targets)
 - rust-lang#131954 (shave 150ms off bootstrap)
 - rust-lang#132015 (Move const trait tests from `ui/rfcs/rfc-2632-const-trait-impl` to `ui/traits/const-traits`)
 - rust-lang#132017 (Update triagebot.toml)

r? `@ghost`
`@rustbot` modify labels: rollup
rust-timer added a commit to rust-lang-ci/rust that referenced this issue Oct 22, 2024
@rust-timer
Unrolled build for rust-lang#130432
f705d43 
Rollup merge of rust-lang#130432 - azhogin:azhogin/regparm, r=workingjubilee,pnkfelix

rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972)

Command line flag `-Zregparm=<N>` for X86 (32-bit) for rust-for-linux: rust-lang#116972
Implemented in the similar way as fastcall/vectorcall support (args are marked InReg if fit).
@ojeda
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ojeda commented Nov 18, 2024

See #131749.

@ojeda ojeda closed this as completed Nov 18, 2024
@ojeda ojeda mentioned this issue Nov 18, 2024
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antoyo pushed a commit to rust-lang/rustc_codegen_gcc that referenced this issue Dec 11, 2024
@workingjubilee
Rollup merge of #130432 - azhogin:azhogin/regparm, r=workingjubilee,p…
cabeeeb 
…nkfelix

rust_for_linux: -Zregparm=<N> commandline flag for X86 (#116972)

Command line flag `-Zregparm=<N>` for X86 (32-bit) for rust-for-linux: rust-lang/rust#116972
Implemented in the similar way as fastcall/vectorcall support (args are marked InReg if fit).
antoyo pushed a commit to antoyo/rust that referenced this issue Jan 13, 2025
@azhogin
rust_for_linux: -Zregparm=<N> commandline flag for X86 (rust-lang#116972
4c297be 
)
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@RalfJung @ojeda @vincenzopalazzo @bjorn3 @rustbot @Noratrieb