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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /vendor/compiler_builtins/src/x86.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/compiler_builtins/src/x86.rs')
-rw-r--r-- | vendor/compiler_builtins/src/x86.rs | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/vendor/compiler_builtins/src/x86.rs b/vendor/compiler_builtins/src/x86.rs new file mode 100644 index 000000000..fd1f32e3a --- /dev/null +++ b/vendor/compiler_builtins/src/x86.rs @@ -0,0 +1,85 @@ +#![allow(unused_imports)] + +use core::intrinsics; + +// NOTE These functions are implemented using assembly because they using a custom +// calling convention which can't be implemented using a normal Rust function + +// NOTE These functions are never mangled as they are not tested against compiler-rt +// and mangling ___chkstk would break the `jmp ___chkstk` instruction in __alloca + +intrinsics! { + #[naked] + #[cfg(all( + windows, + target_env = "gnu", + not(feature = "no-asm") + ))] + pub unsafe extern "C" fn ___chkstk_ms() { + core::arch::asm!( + "push %ecx", + "push %eax", + "cmp $0x1000,%eax", + "lea 12(%esp),%ecx", + "jb 1f", + "2:", + "sub $0x1000,%ecx", + "test %ecx,(%ecx)", + "sub $0x1000,%eax", + "cmp $0x1000,%eax", + "ja 2b", + "1:", + "sub %eax,%ecx", + "test %ecx,(%ecx)", + "pop %eax", + "pop %ecx", + "ret", + options(noreturn, att_syntax) + ); + } + + // FIXME: __alloca should be an alias to __chkstk + #[naked] + #[cfg(all( + windows, + target_env = "gnu", + not(feature = "no-asm") + ))] + pub unsafe extern "C" fn __alloca() { + core::arch::asm!( + "jmp ___chkstk", // Jump to ___chkstk since fallthrough may be unreliable" + options(noreturn, att_syntax) + ); + } + + #[naked] + #[cfg(all( + windows, + target_env = "gnu", + not(feature = "no-asm") + ))] + pub unsafe extern "C" fn ___chkstk() { + core::arch::asm!( + "push %ecx", + "cmp $0x1000,%eax", + "lea 8(%esp),%ecx", // esp before calling this routine -> ecx + "jb 1f", + "2:", + "sub $0x1000,%ecx", + "test %ecx,(%ecx)", + "sub $0x1000,%eax", + "cmp $0x1000,%eax", + "ja 2b", + "1:", + "sub %eax,%ecx", + "test %ecx,(%ecx)", + "lea 4(%esp),%eax", // load pointer to the return address into eax + "mov %ecx,%esp", // install the new top of stack pointer into esp + "mov -4(%eax),%ecx", // restore ecx + "push (%eax)", // push return address onto the stack + "sub %esp,%eax", // restore the original value in eax + "ret", + options(noreturn, att_syntax) + ); + } +} |