diff --git a/src/libextra/rl.rs b/src/libextra/rl.rs index 693e3ecb53fb6..c1eeb5005b265 100644 --- a/src/libextra/rl.rs +++ b/src/libextra/rl.rs @@ -72,11 +72,11 @@ fn complete_key(_v: @CompletionCb) {} /// Bind to the main completion callback pub unsafe fn complete(cb: CompletionCb) { - local_data::local_data_set(complete_key, @(cb)); + local_data::set(complete_key, @(cb)); extern fn callback(line: *c_char, completions: *()) { unsafe { - let cb = *local_data::local_data_get(complete_key) + let cb = *local_data::get(complete_key, |k| k.map(|&k| *k)) .get(); do cb(str::raw::from_c_str(line)) |suggestion| { diff --git a/src/libextra/sort.rs b/src/libextra/sort.rs index 68a678869da13..d4d6162a9198f 100644 --- a/src/libextra/sort.rs +++ b/src/libextra/sort.rs @@ -1204,11 +1204,11 @@ mod big_tests { #[unsafe_destructor] impl<'self> Drop for LVal<'self> { fn drop(&self) { - let x = unsafe { local_data::local_data_get(self.key) }; + let x = unsafe { local_data::get(self.key, |k| k.map(|&k| *k)) }; match x { Some(@y) => { unsafe { - local_data::local_data_set(self.key, @(y+1)); + local_data::set(self.key, @(y+1)); } } _ => fail!("Expected key to work"), diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs index 80fc3803ae732..dc62206fb34c8 100644 --- a/src/librustc/middle/trans/base.rs +++ b/src/librustc/middle/trans/base.rs @@ -92,7 +92,7 @@ fn task_local_insn_key(_v: @~[&'static str]) {} pub fn with_insn_ctxt(blk: &fn(&[&'static str])) { unsafe { - let opt = local_data::local_data_get(task_local_insn_key); + let opt = local_data::get(task_local_insn_key, |k| k.map(|&k| *k)); if opt.is_some() { blk(*opt.unwrap()); } @@ -101,7 +101,7 @@ pub fn with_insn_ctxt(blk: &fn(&[&'static str])) { pub fn init_insn_ctxt() { unsafe { - local_data::local_data_set(task_local_insn_key, @~[]); + local_data::set(task_local_insn_key, @~[]); } } @@ -111,7 +111,7 @@ pub struct _InsnCtxt { _x: () } impl Drop for _InsnCtxt { fn drop(&self) { unsafe { - do local_data::local_data_modify(task_local_insn_key) |c| { + do local_data::modify(task_local_insn_key) |c| { do c.map_consume |ctx| { let mut ctx = copy *ctx; ctx.pop(); @@ -125,7 +125,7 @@ impl Drop for _InsnCtxt { pub fn push_ctxt(s: &'static str) -> _InsnCtxt { debug!("new InsnCtxt: %s", s); unsafe { - do local_data::local_data_modify(task_local_insn_key) |c| { + do local_data::modify(task_local_insn_key) |c| { do c.map_consume |ctx| { let mut ctx = copy *ctx; ctx.push(s); diff --git a/src/librustc/middle/trans/context.rs b/src/librustc/middle/trans/context.rs index 2880c68c1e036..77a565e675f08 100644 --- a/src/librustc/middle/trans/context.rs +++ b/src/librustc/middle/trans/context.rs @@ -241,14 +241,14 @@ impl Drop for CrateContext { fn task_local_llcx_key(_v: @ContextRef) {} pub fn task_llcx() -> ContextRef { - let opt = unsafe { local_data::local_data_get(task_local_llcx_key) }; + let opt = unsafe { local_data::get(task_local_llcx_key, |k| k.map(|&k| *k)) }; *opt.expect("task-local LLVMContextRef wasn't ever set!") } unsafe fn set_task_llcx(c: ContextRef) { - local_data::local_data_set(task_local_llcx_key, @c); + local_data::set(task_local_llcx_key, @c); } unsafe fn unset_task_llcx() { - local_data::local_data_pop(task_local_llcx_key); + local_data::pop(task_local_llcx_key); } diff --git a/src/librusti/program.rs b/src/librusti/program.rs index e15cc04fa9b7e..716c7a2481eed 100644 --- a/src/librusti/program.rs +++ b/src/librusti/program.rs @@ -58,7 +58,7 @@ struct LocalVariable { } type LocalCache = @mut HashMap<~str, @~[u8]>; -fn tls_key(_k: @LocalCache) {} +fn tls_key(_k: LocalCache) {} impl Program { pub fn new() -> Program { @@ -132,7 +132,7 @@ impl Program { "); let key: sys::Closure = unsafe { - let tls_key: &'static fn(@LocalCache) = tls_key; + let tls_key: &'static fn(LocalCache) = tls_key; cast::transmute(tls_key) }; // First, get a handle to the tls map which stores all the local @@ -144,7 +144,7 @@ impl Program { let key = ::std::sys::Closure{ code: %? as *(), env: ::std::ptr::null() }; let key = ::std::cast::transmute(key); - *::std::local_data::local_data_get(key).unwrap() + ::std::local_data::get(key, |k| k.map(|&x| *x)).unwrap() };\n", key.code as uint)); // Using this __tls_map handle, deserialize each variable binding that @@ -227,7 +227,7 @@ impl Program { map.insert(copy *name, @copy value.data); } unsafe { - local_data::local_data_set(tls_key, @map); + local_data::set(tls_key, map); } } @@ -236,7 +236,7 @@ impl Program { /// it updates this cache with the new values of each local variable. pub fn consume_cache(&mut self) { let map = unsafe { - local_data::local_data_pop(tls_key).expect("tls is empty") + local_data::pop(tls_key).expect("tls is empty") }; do map.consume |name, value| { match self.local_vars.find_mut(&name) { diff --git a/src/libstd/condition.rs b/src/libstd/condition.rs index 04f2d815d0815..d6d09527f8301 100644 --- a/src/libstd/condition.rs +++ b/src/libstd/condition.rs @@ -12,7 +12,6 @@ #[allow(missing_doc)]; -use local_data::{local_data_pop, local_data_set}; use local_data; use prelude::*; @@ -26,14 +25,14 @@ pub struct Handler { pub struct Condition<'self, T, U> { name: &'static str, - key: local_data::LocalDataKey<'self, Handler> + key: local_data::Key<'self, @Handler> } impl<'self, T, U> Condition<'self, T, U> { pub fn trap(&'self self, h: &'self fn(T) -> U) -> Trap<'self, T, U> { unsafe { let p : *RustClosure = ::cast::transmute(&h); - let prev = local_data::local_data_get(self.key); + let prev = local_data::get(self.key, |k| k.map(|&x| *x)); let h = @Handler { handle: *p, prev: prev }; Trap { cond: self, handler: h } } @@ -46,7 +45,7 @@ impl<'self, T, U> Condition<'self, T, U> { pub fn raise_default(&self, t: T, default: &fn() -> U) -> U { unsafe { - match local_data_pop(self.key) { + match local_data::pop(self.key) { None => { debug!("Condition.raise: found no handler"); default() @@ -55,12 +54,12 @@ impl<'self, T, U> Condition<'self, T, U> { debug!("Condition.raise: found handler"); match handler.prev { None => {} - Some(hp) => local_data_set(self.key, hp) + Some(hp) => local_data::set(self.key, hp) } let handle : &fn(T) -> U = ::cast::transmute(handler.handle); let u = handle(t); - local_data_set(self.key, handler); + local_data::set(self.key, handler); u } } @@ -78,7 +77,7 @@ impl<'self, T, U> Trap<'self, T, U> { unsafe { let _g = Guard { cond: self.cond }; debug!("Trap: pushing handler to TLS"); - local_data_set(self.cond.key, self.handler); + local_data::set(self.cond.key, self.handler); inner() } } @@ -93,12 +92,12 @@ impl<'self, T, U> Drop for Guard<'self, T, U> { fn drop(&self) { unsafe { debug!("Guard: popping handler from TLS"); - let curr = local_data_pop(self.cond.key); + let curr = local_data::pop(self.cond.key); match curr { None => {} Some(h) => match h.prev { None => {} - Some(hp) => local_data_set(self.cond.key, hp) + Some(hp) => local_data::set(self.cond.key, hp) } } } diff --git a/src/libstd/local_data.rs b/src/libstd/local_data.rs index c5f2c8ae584d1..b241de887004c 100644 --- a/src/libstd/local_data.rs +++ b/src/libstd/local_data.rs @@ -12,14 +12,28 @@ Task local data management -Allows storing boxes with arbitrary types inside, to be accessed -anywhere within a task, keyed by a pointer to a global finaliser -function. Useful for dynamic variables, singletons, and interfacing -with foreign code with bad callback interfaces. +Allows storing boxes with arbitrary types inside, to be accessed anywhere within +a task, keyed by a pointer to a global finaliser function. Useful for dynamic +variables, singletons, and interfacing with foreign code with bad callback +interfaces. -To use, declare a monomorphic global function at the type to store, -and use it as the 'key' when accessing. See the 'tls' tests below for -examples. +To use, declare a monomorphic (no type parameters) global function at the type +to store, and use it as the 'key' when accessing. + +~~~{.rust} +use std::local_data; + +fn key_int(_: @int) {} +fn key_vector(_: @~[int]) {} + +unsafe { + local_data::set(key_int, @3); + assert!(local_data::get(key_int) == Some(@3)); + + local_data::set(key_vector, @~[3]); + assert!(local_data::get(key_vector).unwrap()[0] == 3); +} +~~~ Casting 'Arcane Sight' reveals an overwhelming aura of Transmutation magic. @@ -28,7 +42,7 @@ magic. use prelude::*; -use task::local_data_priv::{local_get, local_pop, local_modify, local_set, Handle}; +use task::local_data_priv::{local_get, local_pop, local_set, Handle}; #[cfg(test)] use task; @@ -46,63 +60,98 @@ use task::local_data_priv::{local_get, local_pop, local_modify, local_set, Handl * * These two cases aside, the interface is safe. */ -pub type LocalDataKey<'self,T> = &'self fn:Copy(v: @T); +pub type Key<'self,T> = &'self fn:Copy(v: T); /** * Remove a task-local data value from the table, returning the * reference that was originally created to insert it. */ -pub unsafe fn local_data_pop( - key: LocalDataKey) -> Option<@T> { - +#[cfg(stage0)] +pub unsafe fn pop(key: Key<@T>) -> Option<@T> { + local_pop(Handle::new(), key) +} +/** + * Remove a task-local data value from the table, returning the + * reference that was originally created to insert it. + */ +#[cfg(not(stage0))] +pub unsafe fn pop(key: Key) -> Option { local_pop(Handle::new(), key) } /** * Retrieve a task-local data value. It will also be kept alive in the * table until explicitly removed. */ -pub unsafe fn local_data_get( - key: LocalDataKey) -> Option<@T> { - - local_get(Handle::new(), key) +#[cfg(stage0)] +pub unsafe fn get(key: Key<@T>, f: &fn(Option<&@T>) -> U) -> U { + local_get(Handle::new(), key, f) +} +/** + * Retrieve a task-local data value. It will also be kept alive in the + * table until explicitly removed. + */ +#[cfg(not(stage0))] +pub unsafe fn get(key: Key, f: &fn(Option<&T>) -> U) -> U { + local_get(Handle::new(), key, f) } /** * Store a value in task-local data. If this key already has a value, * that value is overwritten (and its destructor is run). */ -pub unsafe fn local_data_set( - key: LocalDataKey, data: @T) { - +#[cfg(stage0)] +pub unsafe fn set(key: Key<@T>, data: @T) { + local_set(Handle::new(), key, data) +} +/** + * Store a value in task-local data. If this key already has a value, + * that value is overwritten (and its destructor is run). + */ +#[cfg(not(stage0))] +pub unsafe fn set(key: Key, data: T) { local_set(Handle::new(), key, data) } /** * Modify a task-local data value. If the function returns 'None', the * data is removed (and its reference dropped). */ -pub unsafe fn local_data_modify( - key: LocalDataKey, - modify_fn: &fn(Option<@T>) -> Option<@T>) { - - local_modify(Handle::new(), key, modify_fn) +#[cfg(stage0)] +pub unsafe fn modify(key: Key<@T>, + f: &fn(Option<@T>) -> Option<@T>) { + match f(pop(key)) { + Some(next) => { set(key, next); } + None => {} + } +} +/** + * Modify a task-local data value. If the function returns 'None', the + * data is removed (and its reference dropped). + */ +#[cfg(not(stage0))] +pub unsafe fn modify(key: Key, + f: &fn(Option) -> Option) { + match f(pop(key)) { + Some(next) => { set(key, next); } + None => {} + } } #[test] fn test_tls_multitask() { unsafe { fn my_key(_x: @~str) { } - local_data_set(my_key, @~"parent data"); + set(my_key, @~"parent data"); do task::spawn { // TLS shouldn't carry over. - assert!(local_data_get(my_key).is_none()); - local_data_set(my_key, @~"child data"); - assert!(*(local_data_get(my_key).get()) == + assert!(get(my_key, |k| k.map(|&k| *k)).is_none()); + set(my_key, @~"child data"); + assert!(*(get(my_key, |k| k.map(|&k| *k)).get()) == ~"child data"); // should be cleaned up for us } // Must work multiple times - assert!(*(local_data_get(my_key).get()) == ~"parent data"); - assert!(*(local_data_get(my_key).get()) == ~"parent data"); - assert!(*(local_data_get(my_key).get()) == ~"parent data"); + assert!(*(get(my_key, |k| k.map(|&k| *k)).get()) == ~"parent data"); + assert!(*(get(my_key, |k| k.map(|&k| *k)).get()) == ~"parent data"); + assert!(*(get(my_key, |k| k.map(|&k| *k)).get()) == ~"parent data"); } } @@ -110,9 +159,9 @@ fn test_tls_multitask() { fn test_tls_overwrite() { unsafe { fn my_key(_x: @~str) { } - local_data_set(my_key, @~"first data"); - local_data_set(my_key, @~"next data"); // Shouldn't leak. - assert!(*(local_data_get(my_key).get()) == ~"next data"); + set(my_key, @~"first data"); + set(my_key, @~"next data"); // Shouldn't leak. + assert!(*(get(my_key, |k| k.map(|&k| *k)).get()) == ~"next data"); } } @@ -120,10 +169,10 @@ fn test_tls_overwrite() { fn test_tls_pop() { unsafe { fn my_key(_x: @~str) { } - local_data_set(my_key, @~"weasel"); - assert!(*(local_data_pop(my_key).get()) == ~"weasel"); + set(my_key, @~"weasel"); + assert!(*(pop(my_key).get()) == ~"weasel"); // Pop must remove the data from the map. - assert!(local_data_pop(my_key).is_none()); + assert!(pop(my_key).is_none()); } } @@ -131,20 +180,20 @@ fn test_tls_pop() { fn test_tls_modify() { unsafe { fn my_key(_x: @~str) { } - local_data_modify(my_key, |data| { + modify(my_key, |data| { match data { Some(@ref val) => fail!("unwelcome value: %s", *val), None => Some(@~"first data") } }); - local_data_modify(my_key, |data| { + modify(my_key, |data| { match data { Some(@~"first data") => Some(@~"next data"), Some(@ref val) => fail!("wrong value: %s", *val), None => fail!("missing value") } }); - assert!(*(local_data_pop(my_key).get()) == ~"next data"); + assert!(*(pop(my_key).get()) == ~"next data"); } } @@ -158,7 +207,7 @@ fn test_tls_crust_automorestack_memorial_bug() { // a stack smaller than 1 MB. fn my_key(_x: @~str) { } do task::spawn { - unsafe { local_data_set(my_key, @~"hax"); } + unsafe { set(my_key, @~"hax"); } } } @@ -169,9 +218,9 @@ fn test_tls_multiple_types() { fn int_key(_x: @int) { } do task::spawn { unsafe { - local_data_set(str_key, @~"string data"); - local_data_set(box_key, @@()); - local_data_set(int_key, @42); + set(str_key, @~"string data"); + set(box_key, @@()); + set(int_key, @42); } } } @@ -183,12 +232,12 @@ fn test_tls_overwrite_multiple_types() { fn int_key(_x: @int) { } do task::spawn { unsafe { - local_data_set(str_key, @~"string data"); - local_data_set(int_key, @42); + set(str_key, @~"string data"); + set(int_key, @42); // This could cause a segfault if overwriting-destruction is done // with the crazy polymorphic transmute rather than the provided // finaliser. - local_data_set(int_key, @31337); + set(int_key, @31337); } } } @@ -201,17 +250,17 @@ fn test_tls_cleanup_on_failure() { fn str_key(_x: @~str) { } fn box_key(_x: @@()) { } fn int_key(_x: @int) { } - local_data_set(str_key, @~"parent data"); - local_data_set(box_key, @@()); + set(str_key, @~"parent data"); + set(box_key, @@()); do task::spawn { // spawn_linked - local_data_set(str_key, @~"string data"); - local_data_set(box_key, @@()); - local_data_set(int_key, @42); + set(str_key, @~"string data"); + set(box_key, @@()); + set(int_key, @42); fail!(); } // Not quite nondeterministic. - local_data_set(int_key, @31337); + set(int_key, @31337); fail!(); } } @@ -221,6 +270,14 @@ fn test_static_pointer() { unsafe { fn key(_x: @&'static int) { } static VALUE: int = 0; - local_data_set(key, @&VALUE); + set(key, @&VALUE); + } +} + +#[test] +fn test_owned() { + unsafe { + fn key(_x: ~int) { } + set(key, ~1); } } diff --git a/src/libstd/os.rs b/src/libstd/os.rs index 50acbee697f2b..2e511f91b5abe 100644 --- a/src/libstd/os.rs +++ b/src/libstd/os.rs @@ -1230,7 +1230,7 @@ fn overridden_arg_key(_v: @OverriddenArgs) {} /// `os::set_args` function. pub fn args() -> ~[~str] { unsafe { - match local_data::local_data_get(overridden_arg_key) { + match local_data::get(overridden_arg_key, |k| k.map(|&k| *k)) { None => real_args(), Some(args) => copy args.val } @@ -1243,7 +1243,7 @@ pub fn args() -> ~[~str] { pub fn set_args(new_args: ~[~str]) { unsafe { let overridden_args = @OverriddenArgs { val: copy new_args }; - local_data::local_data_set(overridden_arg_key, overridden_args); + local_data::set(overridden_arg_key, overridden_args); } } diff --git a/src/libstd/rand.rs b/src/libstd/rand.rs index 02c8694bf76e2..bc80bd9dc6aba 100644 --- a/src/libstd/rand.rs +++ b/src/libstd/rand.rs @@ -850,13 +850,13 @@ fn tls_rng_state(_v: @@mut IsaacRng) {} pub fn task_rng() -> @mut IsaacRng { let r : Option<@@mut IsaacRng>; unsafe { - r = local_data::local_data_get(tls_rng_state); + r = local_data::get(tls_rng_state, |k| k.map(|&k| *k)); } match r { None => { unsafe { let rng = @@mut IsaacRng::new_seeded(seed()); - local_data::local_data_set(tls_rng_state, rng); + local_data::set(tls_rng_state, rng); *rng } } diff --git a/src/libstd/rt/task.rs b/src/libstd/rt/task.rs index f5f5aca71f55c..2100e71e9fd23 100644 --- a/src/libstd/rt/task.rs +++ b/src/libstd/rt/task.rs @@ -32,7 +32,7 @@ pub struct Task { } pub struct GarbageCollector; -pub struct LocalStorage(*c_void, Option<~fn(*c_void)>); +pub struct LocalStorage(*c_void, Option); pub struct Unwinder { unwinding: bool, @@ -167,15 +167,15 @@ mod test { #[test] fn tls() { - use local_data::*; + use local_data; do run_in_newsched_task() { unsafe { fn key(_x: @~str) { } - local_data_set(key, @~"data"); - assert!(*local_data_get(key).get() == ~"data"); + local_data::set(key, @~"data"); + assert!(*local_data::get(key, |k| k.map(|&k| *k)).get() == ~"data"); fn key2(_x: @~str) { } - local_data_set(key2, @~"data"); - assert!(*local_data_get(key2).get() == ~"data"); + local_data::set(key2, @~"data"); + assert!(*local_data::get(key2, |k| k.map(|&k| *k)).get() == ~"data"); } } } diff --git a/src/libstd/task/local_data_priv.rs b/src/libstd/task/local_data_priv.rs index 8dd96df454539..42cfcbc16dbf8 100644 --- a/src/libstd/task/local_data_priv.rs +++ b/src/libstd/task/local_data_priv.rs @@ -11,11 +11,13 @@ #[allow(missing_doc)]; use cast; -use cmp::Eq; use libc; +use local_data; use prelude::*; +use ptr; +use sys; use task::rt; -use local_data::LocalDataKey; +use util; use super::rt::rust_task; use rt::task::{Task, LocalStorage}; @@ -43,25 +45,41 @@ impl Handle { } } -pub trait LocalData { } -impl LocalData for @T { } +trait LocalData {} +impl LocalData for T {} -impl Eq for @LocalData { - fn eq(&self, other: &@LocalData) -> bool { - unsafe { - let ptr_a: &(uint, uint) = cast::transmute(self); - let ptr_b: &(uint, uint) = cast::transmute(other); - return ptr_a == ptr_b; - } - } - fn ne(&self, other: &@LocalData) -> bool { !(*self).eq(other) } -} - -// If TLS is used heavily in future, this could be made more efficient with a -// proper map. -type TaskLocalElement = (*libc::c_void, *libc::c_void, @LocalData); -// Has to be a pointer at outermost layer; the foreign call returns void *. -type TaskLocalMap = @mut ~[Option]; +// The task-local-map stores all TLS information for the currently running task. +// It is stored as an owned pointer into the runtime, and it's only allocated +// when TLS is used for the first time. This map must be very carefully +// constructed because it has many mutable loans unsoundly handed out on it to +// the various invocations of TLS requests. +// +// One of the most important operations is loaning a value via `get` to a +// caller. In doing so, the slot that the TLS entry is occupying cannot be +// invalidated because upon returning it's loan state must be updated. Currently +// the TLS map is a vector, but this is possibly dangerous because the vector +// can be reallocated/moved when new values are pushed onto it. +// +// This problem currently isn't solved in a very elegant way. Inside the `get` +// function, it internally "invalidates" all references after the loan is +// finished and looks up into the vector again. In theory this will prevent +// pointers from being moved under our feet so long as LLVM doesn't go too crazy +// with the optimizations. +// +// n.b. Other structures are not sufficient right now: +// * HashMap uses ~[T] internally (push reallocates/moves) +// * TreeMap is plausible, but it's in extra +// * dlist plausible, but not in std +// * a custom owned linked list was attempted, but difficult to write +// and involved a lot of extra code bloat +// +// n.b. Has to be stored with a pointer at outermost layer; the foreign call +// returns void *. +// +// n.b. If TLS is used heavily in future, this could be made more efficient with +// a proper map. +type TaskLocalMap = ~[Option<(*libc::c_void, TLSValue, uint)>]; +type TLSValue = ~LocalData:; fn cleanup_task_local_map(map_ptr: *libc::c_void) { unsafe { @@ -74,162 +92,203 @@ fn cleanup_task_local_map(map_ptr: *libc::c_void) { } // Gets the map from the runtime. Lazily initialises if not done so already. -unsafe fn get_local_map(handle: Handle) -> TaskLocalMap { - match handle { - OldHandle(task) => get_task_local_map(task), - NewHandle(local_storage) => get_newsched_local_map(local_storage) - } -} +unsafe fn get_local_map(handle: Handle) -> &mut TaskLocalMap { -unsafe fn get_task_local_map(task: *rust_task) -> TaskLocalMap { + unsafe fn oldsched_map(task: *rust_task) -> &mut TaskLocalMap { + extern fn cleanup_extern_cb(map_ptr: *libc::c_void) { + cleanup_task_local_map(map_ptr); + } - extern fn cleanup_task_local_map_extern_cb(map_ptr: *libc::c_void) { - cleanup_task_local_map(map_ptr); + // Relies on the runtime initialising the pointer to null. + // Note: the map is an owned pointer and is "owned" by TLS. It is moved + // into the tls slot for this task, and then mutable loans are taken + // from this slot to modify the map. + let map_ptr = rt::rust_get_task_local_data(task); + if (*map_ptr).is_null() { + // First time TLS is used, create a new map and set up the necessary + // TLS information for its safe destruction + let map: TaskLocalMap = ~[]; + *map_ptr = cast::transmute(map); + rt::rust_task_local_data_atexit(task, cleanup_extern_cb); + } + return cast::transmute(map_ptr); } - // Relies on the runtime initialising the pointer to null. - // Note: The map's box lives in TLS invisibly referenced once. Each time - // we retrieve it for get/set, we make another reference, which get/set - // drop when they finish. No "re-storing after modifying" is needed. - let map_ptr = rt::rust_get_task_local_data(task); - if map_ptr.is_null() { - let map: TaskLocalMap = @mut ~[]; - // NB: This bumps the ref count before converting to an unsafe pointer, - // keeping the map alive until TLS is destroyed - rt::rust_set_task_local_data(task, cast::transmute(map)); - rt::rust_task_local_data_atexit(task, cleanup_task_local_map_extern_cb); - map - } else { - let map = cast::transmute(map_ptr); - let nonmut = cast::transmute::]>(map); - cast::bump_box_refcount(nonmut); - map + unsafe fn newsched_map(local: *mut LocalStorage) -> &mut TaskLocalMap { + // This is based on the same idea as the oldsched code above. + match &mut *local { + // If the at_exit function is already set, then we just need to take + // a loan out on the TLS map stored inside + &LocalStorage(ref mut map_ptr, Some(_)) => { + assert!(map_ptr.is_not_null()); + return cast::transmute(map_ptr); + } + // If this is the first time we've accessed TLS, perform similar + // actions to the oldsched way of doing things. + &LocalStorage(ref mut map_ptr, ref mut at_exit) => { + assert!(map_ptr.is_null()); + assert!(at_exit.is_none()); + let map: TaskLocalMap = ~[]; + *map_ptr = cast::transmute(map); + *at_exit = Some(cleanup_task_local_map); + return cast::transmute(map_ptr); + } + } } -} -unsafe fn get_newsched_local_map(local: *mut LocalStorage) -> TaskLocalMap { - match &mut *local { - &LocalStorage(map_ptr, Some(_)) => { - assert!(map_ptr.is_not_null()); - let map = cast::transmute(map_ptr); - let nonmut = cast::transmute::]>(map); - cast::bump_box_refcount(nonmut); - return map; - } - &LocalStorage(ref mut map_ptr, ref mut at_exit) => { - assert!((*map_ptr).is_null()); - let map: TaskLocalMap = @mut ~[]; - *map_ptr = cast::transmute(map); - let at_exit_fn: ~fn(*libc::c_void) = |p|cleanup_task_local_map(p); - *at_exit = Some(at_exit_fn); - return map; - } + match handle { + OldHandle(task) => oldsched_map(task), + NewHandle(local_storage) => newsched_map(local_storage) } } -unsafe fn key_to_key_value(key: LocalDataKey) -> *libc::c_void { - // Keys are closures, which are (fnptr,envptr) pairs. Use fnptr. - // Use reinterpret_cast -- transmute would leak (forget) the closure. - let pair: (*libc::c_void, *libc::c_void) = cast::transmute_copy(&key); - pair.first() +unsafe fn key_to_key_value(key: local_data::Key) -> *libc::c_void { + let pair: sys::Closure = cast::transmute(key); + return pair.code as *libc::c_void; } -// If returning Some(..), returns with @T with the map's reference. Careful! -unsafe fn local_data_lookup( - map: TaskLocalMap, key: LocalDataKey) - -> Option<(uint, *libc::c_void)> { - +pub unsafe fn local_pop(handle: Handle, + key: local_data::Key) -> Option { + let map = get_local_map(handle); let key_value = key_to_key_value(key); - let map_pos = (*map).iter().position(|entry| + + for map.mut_iter().advance |entry| { match *entry { - Some((k,_,_)) => k == key_value, - None => false - } - ); - do map_pos.map |index| { - // .get() is guaranteed because of "None { false }" above. - let (_, data_ptr, _) = (*map)[*index].get(); - (*index, data_ptr) - } -} + Some((k, _, loans)) if k == key_value => { + if loans != 0 { + fail!("TLS value has been loaned via get already"); + } + // Move the data out of the `entry` slot via util::replace. This + // is guaranteed to succeed because we already matched on `Some` + // above. + let data = match util::replace(entry, None) { + Some((_, data, _)) => data, + None => libc::abort(), + }; -unsafe fn local_get_helper( - handle: Handle, key: LocalDataKey, - do_pop: bool) -> Option<@T> { + // Move `data` into transmute to get out the memory that it + // owns, we must free it manually later. + let (_vtable, box): (uint, ~~T) = cast::transmute(data); - let map = get_local_map(handle); - // Interpreturn our findings from the map - do local_data_lookup(map, key).map |result| { - // A reference count magically appears on 'data' out of thin air. It - // was referenced in the local_data box, though, not here, so before - // overwriting the local_data_box we need to give an extra reference. - // We must also give an extra reference when not removing. - let (index, data_ptr) = *result; - let data: @T = cast::transmute(data_ptr); - cast::bump_box_refcount(data); - if do_pop { - map[index] = None; + // Read the box's value (using the compiler's built-in + // auto-deref functionality to obtain a pointer to the base) + let ret = ptr::read_ptr(cast::transmute::<&T, *mut T>(*box)); + + // Finally free the allocated memory. we don't want this to + // actually touch the memory inside because it's all duplicated + // now, so the box is transmuted to a 0-sized type. We also use + // a type which references `T` because currently the layout + // could depend on whether T contains managed pointers or not. + let _: ~~[T, ..0] = cast::transmute(box); + + // Everything is now deallocated, and we own the value that was + // located inside TLS, so we now return it. + return Some(ret); + } + _ => {} } - data } + return None; } +pub unsafe fn local_get(handle: Handle, + key: local_data::Key, + f: &fn(Option<&T>) -> U) -> U { + // This function must be extremely careful. Because TLS can store owned + // values, and we must have some form of `get` function other than `pop`, + // this function has to give a `&` reference back to the caller. + // + // One option is to return the reference, but this cannot be sound because + // the actual lifetime of the object is not known. The slot in TLS could not + // be modified until the object goes out of scope, but the TLS code cannot + // know when this happens. + // + // For this reason, the reference is yielded to a specified closure. This + // way the TLS code knows exactly what the lifetime of the yielded pointer + // is, allowing callers to acquire references to owned data. This is also + // sound so long as measures are taken to ensure that while a TLS slot is + // loaned out to a caller, it's not modified recursively. + let map = get_local_map(handle); + let key_value = key_to_key_value(key); -pub unsafe fn local_pop( - handle: Handle, - key: LocalDataKey) -> Option<@T> { - - local_get_helper(handle, key, true) -} - -pub unsafe fn local_get( - handle: Handle, - key: LocalDataKey) -> Option<@T> { + let pos = map.iter().position(|entry| { + match *entry { + Some((k, _, _)) if k == key_value => true, _ => false + } + }); + match pos { + None => { return f(None); } + Some(i) => { + let ret; + match map[i] { + Some((_, ref data, ref mut loans)) => { + *loans = *loans + 1; + // data was created with `~~T as ~LocalData`, so we extract + // pointer part of the trait, (as ~~T), and then use + // compiler coercions to achieve a '&' pointer + match *cast::transmute::<&TLSValue, &(uint, ~~T)>(data) { + (_vtable, ref box) => { + let value: &T = **box; + ret = f(Some(value)); + } + } + } + _ => libc::abort() + } - local_get_helper(handle, key, false) + // n.b. 'data' and 'loans' are both invalid pointers at the point + // 'f' returned because `f` could have appended more TLS items which + // in turn relocated the vector. Hence we do another lookup here to + // fixup the loans. + match map[i] { + Some((_, _, ref mut loans)) => { *loans = *loans - 1; } + None => { libc::abort(); } + } + return ret; + } + } } -pub unsafe fn local_set( - handle: Handle, key: LocalDataKey, data: @T) { - +pub unsafe fn local_set(handle: Handle, + key: local_data::Key, + data: T) { let map = get_local_map(handle); - // Store key+data as *voids. Data is invisibly referenced once; key isn't. let keyval = key_to_key_value(key); - // We keep the data in two forms: one as an unsafe pointer, so we can get - // it back by casting; another in an existential box, so the reference we - // own on it can be dropped when the box is destroyed. The unsafe pointer - // does not have a reference associated with it, so it may become invalid - // when the box is destroyed. - let data_ptr = *cast::transmute::<&@T, &*libc::c_void>(&data); - let data_box = @data as @LocalData; - // Construct new entry to store in the map. - let new_entry = Some((keyval, data_ptr, data_box)); - // Find a place to put it. - match local_data_lookup(map, key) { - Some((index, _old_data_ptr)) => { - // Key already had a value set, _old_data_ptr, whose reference - // will get dropped when the local_data box is overwritten. - map[index] = new_entry; - } - None => { - // Find an empty slot. If not, grow the vector. - match (*map).iter().position(|x| x.is_none()) { - Some(empty_index) => { map[empty_index] = new_entry; } - None => { map.push(new_entry); } + + // When the task-local map is destroyed, all the data needs to be cleaned + // up. For this reason we can't do some clever tricks to store '~T' as a + // '*c_void' or something like that. To solve the problem, we cast + // everything to a trait (LocalData) which is then stored inside the map. + // Upon destruction of the map, all the objects will be destroyed and the + // traits have enough information about them to destroy themselves. + // + // FIXME(#7673): This should be "~data as ~LocalData" (without the colon at + // the end, and only one sigil) + let data = ~~data as ~LocalData:; + + fn insertion_position(map: &mut TaskLocalMap, + key: *libc::c_void) -> Option { + // First see if the map contains this key already + let curspot = map.iter().position(|entry| { + match *entry { + Some((ekey, _, loans)) if key == ekey => { + if loans != 0 { + fail!("TLS value has been loaned via get already"); + } + true + } + _ => false, } + }); + // If it doesn't contain the key, just find a slot that's None + match curspot { + Some(i) => Some(i), + None => map.iter().position(|entry| entry.is_none()) } } -} - -pub unsafe fn local_modify( - handle: Handle, key: LocalDataKey, - modify_fn: &fn(Option<@T>) -> Option<@T>) { - // Could be more efficient by doing the lookup work, but this is easy. - let newdata = modify_fn(local_pop(handle, key)); - if newdata.is_some() { - local_set(handle, key, newdata.unwrap()); + match insertion_position(map, keyval) { + Some(i) => { map[i] = Some((keyval, data, 0)); } + None => { map.push(Some((keyval, data, 0))); } } } diff --git a/src/libstd/task/local_data_priv_stage0.rs b/src/libstd/task/local_data_priv_stage0.rs new file mode 100644 index 0000000000000..fe80ec06c69d0 --- /dev/null +++ b/src/libstd/task/local_data_priv_stage0.rs @@ -0,0 +1,229 @@ +// Copyright 2012 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#[allow(missing_doc)]; + +use cast; +use cmp::Eq; +use libc; +use local_data; +use prelude::*; +use sys; +use task::rt; + +use super::rt::rust_task; +use rt::task::{Task, LocalStorage}; + +pub enum Handle { + OldHandle(*rust_task), + NewHandle(*mut LocalStorage) +} + +impl Handle { + pub fn new() -> Handle { + use rt::{context, OldTaskContext}; + use rt::local::Local; + unsafe { + match context() { + OldTaskContext => { + OldHandle(rt::rust_get_task()) + } + _ => { + let task = Local::unsafe_borrow::(); + NewHandle(&mut (*task).storage) + } + } + } + } +} + +pub trait LocalData { } +impl LocalData for @T { } + +impl Eq for @LocalData { + fn eq(&self, other: &@LocalData) -> bool { + unsafe { + let ptr_a: &(uint, uint) = cast::transmute(self); + let ptr_b: &(uint, uint) = cast::transmute(other); + return ptr_a == ptr_b; + } + } + fn ne(&self, other: &@LocalData) -> bool { !(*self).eq(other) } +} + +// If TLS is used heavily in future, this could be made more efficient with a +// proper map. +type TaskLocalElement = (*libc::c_void, *libc::c_void, @LocalData); +// Has to be a pointer at outermost layer; the foreign call returns void *. +type TaskLocalMap = ~[Option]; + +fn cleanup_task_local_map(map_ptr: *libc::c_void) { + unsafe { + assert!(!map_ptr.is_null()); + // Get and keep the single reference that was created at the + // beginning. + let _map: TaskLocalMap = cast::transmute(map_ptr); + // All local_data will be destroyed along with the map. + } +} + +// Gets the map from the runtime. Lazily initialises if not done so already. +unsafe fn get_local_map(handle: Handle) -> &mut TaskLocalMap { + match handle { + OldHandle(task) => get_task_local_map(task), + NewHandle(local_storage) => get_newsched_local_map(local_storage) + } +} + +unsafe fn get_task_local_map(task: *rust_task) -> &mut TaskLocalMap { + + extern fn cleanup_task_local_map_extern_cb(map_ptr: *libc::c_void) { + cleanup_task_local_map(map_ptr); + } + + // Relies on the runtime initialising the pointer to null. + // Note: the map is an owned pointer and is "owned" by TLS. It is moved + // into the tls slot for this task, and then mutable loans are taken from + // this slot to modify the map. + let map_ptr = rt::rust_get_task_local_data(task); + if (*map_ptr).is_null() { + // First time TLS is used, create a new map and set up the necessary + // TLS information for its safe destruction + let map: TaskLocalMap = ~[]; + *map_ptr = cast::transmute(map); + rt::rust_task_local_data_atexit(task, cleanup_task_local_map_extern_cb); + } + return cast::transmute(map_ptr); +} + +unsafe fn get_newsched_local_map(local: *mut LocalStorage) -> &mut TaskLocalMap { + // This is based on the same idea as the oldsched code above. + match &mut *local { + // If the at_exit function is already set, then we just need to take a + // loan out on the TLS map stored inside + &LocalStorage(ref mut map_ptr, Some(_)) => { + assert!(map_ptr.is_not_null()); + return cast::transmute(map_ptr); + } + // If this is the first time we've accessed TLS, perform similar + // actions to the oldsched way of doing things. + &LocalStorage(ref mut map_ptr, ref mut at_exit) => { + assert!(map_ptr.is_null()); + assert!(at_exit.is_none()); + let map: TaskLocalMap = ~[]; + *map_ptr = cast::transmute(map); + *at_exit = Some(cleanup_task_local_map); + return cast::transmute(map_ptr); + } + } +} + +unsafe fn key_to_key_value(key: local_data::Key<@T>) -> *libc::c_void { + let pair: sys::Closure = cast::transmute(key); + return pair.code as *libc::c_void; +} + +// If returning Some(..), returns with @T with the map's reference. Careful! +unsafe fn local_data_lookup( + map: &mut TaskLocalMap, key: local_data::Key<@T>) + -> Option<(uint, *libc::c_void)> { + + let key_value = key_to_key_value(key); + for map.iter().enumerate().advance |(i, entry)| { + match *entry { + Some((k, data, _)) if k == key_value => { return Some((i, data)); } + _ => {} + } + } + return None; +} + +unsafe fn local_get_helper( + handle: Handle, key: local_data::Key<@T>, + do_pop: bool) -> Option<@T> { + + let map = get_local_map(handle); + // Interpreturn our findings from the map + do local_data_lookup(map, key).map |result| { + // A reference count magically appears on 'data' out of thin air. It + // was referenced in the local_data box, though, not here, so before + // overwriting the local_data_box we need to give an extra reference. + // We must also give an extra reference when not removing. + let (index, data_ptr) = *result; + let data: @T = cast::transmute(data_ptr); + cast::bump_box_refcount(data); + if do_pop { + map[index] = None; + } + data + } +} + + +pub unsafe fn local_pop( + handle: Handle, + key: local_data::Key<@T>) -> Option<@T> { + + local_get_helper(handle, key, true) +} + +pub unsafe fn local_get( + handle: Handle, + key: local_data::Key<@T>, + f: &fn(Option<&@T>) -> U) -> U { + + match local_get_helper(handle, key, false) { + Some(ref x) => f(Some(x)), + None => f(None) + } +} + +pub unsafe fn local_set( + handle: Handle, key: local_data::Key<@T>, data: @T) { + + let map = get_local_map(handle); + // Store key+data as *voids. Data is invisibly referenced once; key isn't. + let keyval = key_to_key_value(key); + // We keep the data in two forms: one as an unsafe pointer, so we can get + // it back by casting; another in an existential box, so the reference we + // own on it can be dropped when the box is destroyed. The unsafe pointer + // does not have a reference associated with it, so it may become invalid + // when the box is destroyed. + let data_ptr = *cast::transmute::<&@T, &*libc::c_void>(&data); + let data_box = @data as @LocalData; + // Construct new entry to store in the map. + let new_entry = Some((keyval, data_ptr, data_box)); + // Find a place to put it. + match local_data_lookup(map, key) { + Some((index, _old_data_ptr)) => { + // Key already had a value set, _old_data_ptr, whose reference + // will get dropped when the local_data box is overwritten. + map[index] = new_entry; + } + None => { + // Find an empty slot. If not, grow the vector. + match map.iter().position(|x| x.is_none()) { + Some(empty_index) => { map[empty_index] = new_entry; } + None => { map.push(new_entry); } + } + } + } +} + +pub unsafe fn local_modify( + handle: Handle, key: local_data::Key<@T>, + modify_fn: &fn(Option<@T>) -> Option<@T>) { + + // Could be more efficient by doing the lookup work, but this is easy. + let newdata = modify_fn(local_pop(handle, key)); + if newdata.is_some() { + local_set(handle, key, newdata.unwrap()); + } +} diff --git a/src/libstd/task/mod.rs b/src/libstd/task/mod.rs index a8e8cfd163ad7..b012a834ed041 100644 --- a/src/libstd/task/mod.rs +++ b/src/libstd/task/mod.rs @@ -54,6 +54,10 @@ use util; #[cfg(test)] use ptr; #[cfg(test)] use task; +#[cfg(stage0)] +#[path="local_data_priv_stage0.rs"] +mod local_data_priv; +#[cfg(not(stage0))] mod local_data_priv; pub mod rt; pub mod spawn; diff --git a/src/libstd/task/rt.rs b/src/libstd/task/rt.rs index 4860ab36f7729..76fcad0759af3 100644 --- a/src/libstd/task/rt.rs +++ b/src/libstd/task/rt.rs @@ -63,9 +63,7 @@ pub extern { fn rust_task_kill_all(task: *rust_task); #[rust_stack] - fn rust_get_task_local_data(task: *rust_task) -> *libc::c_void; - #[rust_stack] - fn rust_set_task_local_data(task: *rust_task, map: *libc::c_void); + fn rust_get_task_local_data(task: *rust_task) -> *mut *libc::c_void; #[rust_stack] fn rust_task_local_data_atexit(task: *rust_task, cleanup_fn: *u8); } diff --git a/src/libstd/task/spawn.rs b/src/libstd/task/spawn.rs index 190485a720aa7..7fe640dbf8c5b 100644 --- a/src/libstd/task/spawn.rs +++ b/src/libstd/task/spawn.rs @@ -477,26 +477,28 @@ fn gen_child_taskgroup(linked: bool, supervised: bool) * Step 1. Get spawner's taskgroup info. *##################################################################*/ let spawner_group: @@mut TCB = - match local_get(OldHandle(spawner), taskgroup_key!()) { - None => { - // Main task, doing first spawn ever. Lazily initialise - // here. - let mut members = new_taskset(); - taskset_insert(&mut members, spawner); - let tasks = exclusive(Some(TaskGroupData { - members: members, - descendants: new_taskset(), - })); - // Main task/group has no ancestors, no notifier, etc. - let group = @@mut TCB(spawner, - tasks, - AncestorList(None), - true, - None); - local_set(OldHandle(spawner), taskgroup_key!(), group); - group + do local_get(OldHandle(spawner), taskgroup_key!()) |group| { + match group { + None => { + // Main task, doing first spawn ever. Lazily initialise + // here. + let mut members = new_taskset(); + taskset_insert(&mut members, spawner); + let tasks = exclusive(Some(TaskGroupData { + members: members, + descendants: new_taskset(), + })); + // Main task/group has no ancestors, no notifier, etc. + let group = @@mut TCB(spawner, + tasks, + AncestorList(None), + true, + None); + local_set(OldHandle(spawner), taskgroup_key!(), group); + group + } + Some(&group) => group } - Some(group) => group }; let spawner_group: &mut TCB = *spawner_group; diff --git a/src/libsyntax/ast_util.rs b/src/libsyntax/ast_util.rs index 78be8e6f180af..1942cb6ad5692 100644 --- a/src/libsyntax/ast_util.rs +++ b/src/libsyntax/ast_util.rs @@ -698,10 +698,10 @@ pub fn get_sctable() -> @mut SCTable { let sctable_key = (cast::transmute::<(uint, uint), &fn:Copy(v: @@mut SCTable)>( (-4 as uint, 0u))); - match local_data::local_data_get(sctable_key) { + match local_data::get(sctable_key, |k| k.map(|&k| *k)) { None => { let new_table = @@mut new_sctable_internal(); - local_data::local_data_set(sctable_key,new_table); + local_data::set(sctable_key,new_table); *new_table }, Some(intr) => *intr diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs index 09d6ecb40fc0b..46e0ef32321a5 100644 --- a/src/libsyntax/parse/token.rs +++ b/src/libsyntax/parse/token.rs @@ -490,11 +490,11 @@ pub fn get_ident_interner() -> @ident_interner { (cast::transmute::<(uint, uint), &fn:Copy(v: @@::parse::token::ident_interner)>( (-3 as uint, 0u))); - match local_data::local_data_get(key) { + match local_data::get(key, |k| k.map(|&k| *k)) { Some(interner) => *interner, None => { let interner = mk_fresh_ident_interner(); - local_data::local_data_set(key, @interner); + local_data::set(key, @interner); interner } } diff --git a/src/rt/rust_builtin.cpp b/src/rt/rust_builtin.cpp index 17f36e810cd1a..f240c7fa28ab1 100644 --- a/src/rt/rust_builtin.cpp +++ b/src/rt/rust_builtin.cpp @@ -672,14 +672,10 @@ rust_unlock_little_lock(lock_and_signal *lock) { lock->unlock(); } -// set/get/atexit task_local_data can run on the rust stack for speed. -extern "C" void * +// get/atexit task_local_data can run on the rust stack for speed. +extern "C" void ** rust_get_task_local_data(rust_task *task) { - return task->task_local_data; -} -extern "C" void -rust_set_task_local_data(rust_task *task, void *data) { - task->task_local_data = data; + return &task->task_local_data; } extern "C" void rust_task_local_data_atexit(rust_task *task, void (*cleanup_fn)(void *data)) { diff --git a/src/rt/rustrt.def.in b/src/rt/rustrt.def.in index 0da04e34f495d..55caf03822739 100644 --- a/src/rt/rustrt.def.in +++ b/src/rt/rustrt.def.in @@ -171,7 +171,6 @@ rust_destroy_little_lock rust_lock_little_lock rust_unlock_little_lock rust_get_task_local_data -rust_set_task_local_data rust_task_local_data_atexit rust_task_ref rust_task_deref diff --git a/src/test/compile-fail/core-tls-store-pointer.rs b/src/test/compile-fail/core-tls-store-pointer.rs index 63bbaf80177e1..13c9966922889 100644 --- a/src/test/compile-fail/core-tls-store-pointer.rs +++ b/src/test/compile-fail/core-tls-store-pointer.rs @@ -10,12 +10,12 @@ // Testing that we can't store a borrowed pointer it task-local storage -use std::local_data::*; +use std::local_data; fn key(_x: @&int) { } fn main() { unsafe { - local_data_set(key, @&0); //~ ERROR does not fulfill `'static` + local_data::set(key, @&0); //~ ERROR does not fulfill `'static` } }