forked from M-Labs/libfringe
Don't use core::intrinsics.
The core::intrinsics::unreachable() we used at the end of every naked function is essentially pointless, as #[naked] implies that intrinsic at the end of the function. rustc currently does not implement that behavior (rust-lang/rust#32487), but it is a bug. On top of that, anything except a single asm!() in naked functions is likely to be disallowed in the future (rust-lang/rust#32490). A nice side effect is that we avoid the core_intrinsics feature, which will be never stabilized, though neither asm nor naked_functions are likely to be stabilized soon.
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@ -28,7 +28,6 @@
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// after. A .cfi_def_* pseudoinstruction changes the CFA value similarly.
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// * Simulating return is as easy as restoring register values from the CFI table
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// and then setting stack pointer to CFA.
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use core::intrinsics;
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use stack::Stack;
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#[derive(Debug)]
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@ -36,7 +35,7 @@ pub struct StackPointer(*mut usize);
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pub unsafe fn init(stack: &Stack, f: unsafe extern "C" fn(usize) -> !) -> StackPointer {
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#[naked]
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unsafe extern "C" fn init_trampoline_1() -> ! {
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unsafe extern "C" fn init_trampoline_1() {
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asm!(
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r#"
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# gdb has a hardcoded check that rejects backtraces where frame addresses
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@ -60,12 +59,11 @@ pub unsafe fn init(stack: &Stack, f: unsafe extern "C" fn(usize) -> !) -> StackP
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.Lend:
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.size __morestack, .Lend-__morestack
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"#
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: : "s" (init_trampoline_2 as usize) : "memory" : "volatile");
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intrinsics::unreachable()
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: : "s" (init_trampoline_2 as usize) : "memory" : "volatile")
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}
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#[naked]
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unsafe extern "C" fn init_trampoline_2() -> ! {
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unsafe extern "C" fn init_trampoline_2() {
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asm!(
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r#"
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# Set up the second part of our DWARF CFI.
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@ -78,8 +76,7 @@ pub unsafe fn init(stack: &Stack, f: unsafe extern "C" fn(usize) -> !) -> StackP
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# Call the provided function.
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call *8(%esp)
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"#
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: : : "memory" : "volatile");
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intrinsics::unreachable()
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: : : "memory" : "volatile")
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}
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unsafe fn push(sp: &mut StackPointer, val: usize) {
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@ -102,7 +99,7 @@ pub unsafe fn swap(arg: usize, old_sp: &mut StackPointer, new_sp: &StackPointer,
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let new_cfa = (new_stack.top() as *mut usize).offset(-1);
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#[naked]
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unsafe extern "C" fn swap_trampoline() -> ! {
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unsafe extern "C" fn swap_trampoline() {
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asm!(
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r#"
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# Save frame pointer explicitly; the unwinder uses it to find CFA of
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@ -125,8 +122,7 @@ pub unsafe fn swap(arg: usize, old_sp: &mut StackPointer, new_sp: &StackPointer,
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popl %ebx
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jmpl *%ebx
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"#
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: : : "memory" : "volatile");
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intrinsics::unreachable();
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: : : "memory" : "volatile")
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}
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let ret: usize;
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@ -32,7 +32,6 @@
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// after. A .cfi_def_* pseudoinstruction changes the CFA value similarly.
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// * Simulating return is as easy as restoring register values from the CFI table
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// and then setting stack pointer to CFA.
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use core::intrinsics;
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use stack::Stack;
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#[derive(Debug)]
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@ -40,7 +39,7 @@ pub struct StackPointer(*mut usize);
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pub unsafe fn init(stack: &Stack, f: unsafe extern "C" fn(usize) -> !) -> StackPointer {
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#[naked]
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unsafe extern "C" fn init_trampoline_1() -> ! {
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unsafe extern "C" fn init_trampoline_1() {
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asm!(
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r#"
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# gdb has a hardcoded check that rejects backtraces where frame addresses
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@ -64,12 +63,11 @@ pub unsafe fn init(stack: &Stack, f: unsafe extern "C" fn(usize) -> !) -> StackP
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.Lend:
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.size __morestack, .Lend-__morestack
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"#
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: : "s" (init_trampoline_2 as usize) : "memory" : "volatile");
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intrinsics::unreachable()
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: : "s" (init_trampoline_2 as usize) : "memory" : "volatile")
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}
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#[naked]
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unsafe extern "C" fn init_trampoline_2() -> ! {
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unsafe extern "C" fn init_trampoline_2() {
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asm!(
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r#"
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# Set up the second part of our DWARF CFI.
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@ -79,8 +77,7 @@ pub unsafe fn init(stack: &Stack, f: unsafe extern "C" fn(usize) -> !) -> StackP
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# Call the provided function.
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call *8(%rsp)
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"#
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: : : "memory" : "volatile");
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intrinsics::unreachable()
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: : : "memory" : "volatile")
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}
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unsafe fn push(sp: &mut StackPointer, val: usize) {
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@ -104,7 +101,7 @@ pub unsafe fn swap(arg: usize, old_sp: &mut StackPointer, new_sp: &StackPointer,
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let new_cfa = (new_stack.top() as *mut usize).offset(-1);
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#[naked]
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unsafe extern "C" fn swap_trampoline() -> ! {
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unsafe extern "C" fn swap_trampoline() {
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asm!(
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r#"
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# Save frame pointer explicitly; the unwinder uses it to find CFA of
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@ -127,8 +124,7 @@ pub unsafe fn swap(arg: usize, old_sp: &mut StackPointer, new_sp: &StackPointer,
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popq %rbx
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jmpq *%rbx
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"#
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: : : "memory" : "volatile");
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intrinsics::unreachable();
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: : : "memory" : "volatile")
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}
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let ret: usize;
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@ -1,10 +1,8 @@
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// This file is part of libfringe, a low-level green threading library.
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// Copyright (c) edef <edef@edef.eu>
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// See the LICENSE file included in this distribution.
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#![feature(asm)]
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#![feature(asm, naked_functions)]
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#![cfg_attr(test, feature(test, thread_local, const_fn))]
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#![cfg_attr(target_arch = "x86", feature(naked_functions, core_intrinsics))]
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#![cfg_attr(target_arch = "x86_64", feature(naked_functions, core_intrinsics))]
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#![no_std]
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//! libfringe is a library implementing safe, lightweight context switches,
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