68 lines
2.0 KiB
Rust
68 lines
2.0 KiB
Rust
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
|
|
#[cfg(windows)]
|
|
#[naked]
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub unsafe fn ___chkstk_ms() {
|
|
asm!("push %rcx
|
|
push %rax
|
|
cmp $$0x1000,%rax
|
|
lea 24(%rsp),%rcx
|
|
jb 1f
|
|
2:
|
|
sub $$0x1000,%rcx
|
|
test %rcx,(%rcx)
|
|
sub $$0x1000,%rax
|
|
cmp $$0x1000,%rax
|
|
ja 2b
|
|
1:
|
|
sub %rax,%rcx
|
|
test %rcx,(%rcx)
|
|
pop %rax
|
|
pop %rcx
|
|
ret");
|
|
intrinsics::unreachable();
|
|
}
|
|
|
|
#[cfg(windows)]
|
|
#[naked]
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub unsafe fn __alloca() {
|
|
asm!("mov %rcx,%rax // x64 _alloca is a normal function with parameter in rcx");
|
|
// The original behavior had __alloca fall through to ___chkstk here, but
|
|
// I don't believe that this behavior is guaranteed, and a program that uses
|
|
// only __alloca could have ___chkstk removed by --gc-sections. Call
|
|
// ___chkstk here to guarantee that neither of those happen.
|
|
___chkstk();
|
|
}
|
|
|
|
#[cfg(windows)]
|
|
#[naked]
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub unsafe fn ___chkstk() {
|
|
asm!("push %rcx
|
|
cmp $$0x1000,%rax
|
|
lea 16(%rsp),%rcx // rsp before calling this routine -> rcx
|
|
jb 1f
|
|
2:
|
|
sub $$0x1000,%rcx
|
|
test %rcx,(%rcx)
|
|
sub $$0x1000,%rax
|
|
cmp $$0x1000,%rax
|
|
ja 2b
|
|
1:
|
|
sub %rax,%rcx
|
|
test %rcx,(%rcx)
|
|
|
|
lea 8(%rsp),%rax // load pointer to the return address into rax
|
|
mov %rcx,%rsp // install the new top of stack pointer into rsp
|
|
mov -8(%rax),%rcx // restore rcx
|
|
push (%rax) // push return address onto the stack
|
|
sub %rsp,%rax // restore the original value in rax
|
|
ret");
|
|
intrinsics::unreachable();
|
|
}
|
|
|