6d8330afb6
This commit resumes management of the stack boundaries and limits when switching between tasks. This additionally leverages the __morestack function to run code on "stack overflow". The current behavior is to abort the process, but this is probably not the best behavior in the long term (for deails, see the comment I wrote up in the stack exhaustion routine).
131 lines
3.7 KiB
Rust
131 lines
3.7 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use libc::c_void;
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#[cfg(unix)]
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use libc::c_int;
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#[cfg(unix)]
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use ptr::null;
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#[cfg(windows)]
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use libc::types::os::arch::extra::{DWORD, LPVOID, BOOL};
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#[cfg(unix)]
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pub type Key = pthread_key_t;
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#[cfg(unix)]
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#[fixed_stack_segment]
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#[inline(never)]
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pub unsafe fn create(key: &mut Key) {
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assert_eq!(0, pthread_key_create(key, null()));
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}
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#[cfg(unix)]
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pub unsafe fn set(key: Key, value: *mut c_void) {
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assert_eq!(0, pthread_setspecific(key, value));
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}
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#[cfg(unix)]
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pub unsafe fn get(key: Key) -> *mut c_void {
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pthread_getspecific(key)
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}
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#[cfg(target_os="macos")]
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#[allow(non_camel_case_types)] // foreign type
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type pthread_key_t = ::libc::c_ulong;
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#[cfg(target_os="linux")]
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#[cfg(target_os="freebsd")]
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#[cfg(target_os="android")]
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#[allow(non_camel_case_types)] // foreign type
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type pthread_key_t = ::libc::c_uint;
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#[cfg(unix)]
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extern {
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fn pthread_key_create(key: *mut pthread_key_t, dtor: *u8) -> c_int;
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// This function is a very cheap operation on both osx and unix. On osx, it
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// turns out it's just three instructions, and on unix it's a cheap function
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// which only uses a very small amount of stack.
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//
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// This is not marked as such because we think it has a small stack, but
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// rather we would like to be able to fetch information from
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// thread-local-storage when a task is running very low on its stack budget.
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// For example, this is invoked whenever stack overflow is detected, and we
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// obviously have very little budget to deal with (certainly not anything
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// close to a fixed_stack_segment)
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#[rust_stack]
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fn pthread_getspecific(key: pthread_key_t) -> *mut c_void;
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#[rust_stack]
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fn pthread_setspecific(key: pthread_key_t, value: *mut c_void) -> c_int;
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}
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#[cfg(windows)]
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pub type Key = DWORD;
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#[cfg(windows)]
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#[fixed_stack_segment]
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#[inline(never)]
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pub unsafe fn create(key: &mut Key) {
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static TLS_OUT_OF_INDEXES: DWORD = 0xFFFFFFFF;
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*key = TlsAlloc();
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assert!(*key != TLS_OUT_OF_INDEXES);
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}
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#[cfg(windows)]
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pub unsafe fn set(key: Key, value: *mut c_void) {
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assert!(0 != TlsSetValue(key, value))
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}
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#[cfg(windows)]
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pub unsafe fn get(key: Key) -> *mut c_void {
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TlsGetValue(key)
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}
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#[cfg(windows, target_arch = "x86")]
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extern "stdcall" {
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fn TlsAlloc() -> DWORD;
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// See the reasoning in pthread_getspecific as to why this has the
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// 'rust_stack' attribute, as this function was also verified to only
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// require a small amount of stack.
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#[rust_stack]
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fn TlsGetValue(dwTlsIndex: DWORD) -> LPVOID;
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#[rust_stack]
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fn TlsSetValue(dwTlsIndex: DWORD, lpTlsvalue: LPVOID) -> BOOL;
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}
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#[cfg(windows, target_arch = "x86_64")]
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extern {
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fn TlsAlloc() -> DWORD;
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// See above.
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#[rust_stack]
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fn TlsGetValue(dwTlsIndex: DWORD) -> LPVOID;
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#[rust_stack]
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fn TlsSetValue(dwTlsIndex: DWORD, lpTlsvalue: LPVOID) -> BOOL;
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}
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#[test]
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fn tls_smoke_test() {
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use cast::transmute;
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unsafe {
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let mut key = 0;
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let value = ~20;
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create(&mut key);
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set(key, transmute(value));
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let value: ~int = transmute(get(key));
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assert_eq!(value, ~20);
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let value = ~30;
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set(key, transmute(value));
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let value: ~int = transmute(get(key));
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assert_eq!(value, ~30);
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}
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}
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