Define shims for stack probes using naked functions with RFC 2873 style asm! #2082
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…le asm!. This should fix #1722.
nlewycky
requested review from
MarkMcCaskey and
syrusakbary
and removed request for
syrusakbary
| cfg_if::cfg_if! { | ||
| if #[cfg(all( | ||
| target_os = "windows", | ||
| target_env = "msvc", | ||
| target_pointer_width = "64" | ||
| ))] { | ||
| extern "C" { | ||
| /// The probestack for Windows when compiled with MSVC | ||
| pub fn __chkstk(); | ||
| } | ||
| /// Probestack check | ||
| #[naked] | ||
| #[no_mangle] | ||
| pub unsafe extern "C" fn wasmer_probestack() { | ||
| asm!("jmp {}", sym __chkstk, options (noreturn)); | ||
| } | ||
| } else if #[cfg(all(target_os = "windows", target_env = "gnu"))] { | ||
| extern "C" { | ||
| /// ___chkstk (note the triple underscore) is implemented in compiler-builtins/src/x86_64.rs | ||
| /// by the Rust compiler for the MinGW target | ||
| pub fn ___chkstk(); | ||
| } | ||
| /// Probestack check | ||
| #[naked] | ||
| #[no_mangle] | ||
| pub unsafe extern "C" fn wasmer_probestack() { | ||
| asm!("jmp {}", sym ___chkstk, options (noreturn)); | ||
| } | ||
| } else if #[cfg(any(target_arch = "x86_64", target_arch="x86"))] { | ||
| extern "C" { | ||
| /// Stack probe function for rust. | ||
| pub fn __rust_probestack(); | ||
| } | ||
| /// Probestack check | ||
| #[naked] | ||
| #[no_mangle] | ||
| pub unsafe extern "C" fn wasmer_probestack() { | ||
| asm!("jmp {}", sym __rust_probestack, options (noreturn)); | ||
| } | ||
| } else { | ||
| /// Probestack check is not used on this platform. | ||
| #[no_mangle] | ||
| pub unsafe extern "C" fn wasmer_probestack() { | ||
| panic!(); | ||
| } | ||
| } | ||
| } |
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It might be a good idea to move this to the probestack file, if possible
|
👍 |
Hywan
added
bug
| #![feature(asm)] | ||
| #![feature(naked_functions)] |
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Consider cfg_attr(nightly, feature(asm))
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If we want to ship a nightly-only feature
| cfg_if::cfg_if! { | ||
| if #[cfg(all( | ||
| target_os = "windows", | ||
| target_env = "msvc", | ||
| target_pointer_width = "64" | ||
| ))] { |
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And if we want to ship this for nigthly-only, we should feature gate this code based on nightly vs not nightly
C proper, as in official standard C, doesn't permit assembly in it either. That said, gcc and clang support assembly in C files for linux and mac with the same syntax. We'd need to do something different for Windows though. |
|
Closing this as it was fixed by #2548 |
This should fix #1722.
It's not clear whether we can merge this, new features are enabled in the lib.rs