Making more of the rust_task structure directly accessible from Rust.

src/lib/comm.rs

@@ -8,7 +8,6 @@ export _chan;
 export _port;
 
 export mk_port;
-export chan_from_unsafe_ptr;
 export send;
 export recv;
 export chan;
@@ -47,7 +46,6 @@ resource port_ptr(po: *rustrt::rust_port) {
 type port<~T> = @port_ptr;
 
 obj port_obj<~T>(raw_port : port<T>) {
-    // FIXME: rename this to chan once chan is not a keyword.
     fn mk_chan() -> _chan<T> {
         chan::<T>(raw_port)
     }

src/lib/ptr.rs

@@ -10,3 +10,4 @@ fn offset<T>(ptr: *T, count: uint) -> *T {
     ret rusti::ptr_offset(ptr, count);
 }
 
+fn null<T>() -> *T { ret unsafe::reinterpret_cast(0u); }

src/lib/task.rs

@@ -4,6 +4,7 @@ import comm::_chan;
 import option::some;
 import option::none;
 import option = option::t;
+import ptr;
 
 native "rust" mod rustrt {
     fn task_sleep(time_in_us: uint);
@@ -19,9 +20,8 @@ native "rust" mod rustrt {
     fn set_min_stack(stack_size: uint);
 
     fn new_task() -> task_id;
-    fn drop_task(id : task_id);
+    fn drop_task(task : *rust_task);
     fn get_task_pointer(id : task_id) -> *rust_task;
-    fn get_task_context(id : task_id) -> *x86_registers;
     fn start_task(id : task_id);
     fn get_task_trampoline() -> u32;
 
@@ -31,10 +31,26 @@ native "rust" mod rustrt {
 }
 
 type rust_task = {
+    id : task,
     mutable notify_enabled : u8,
-    mutable notify_chan : _chan<task_notification>
+    mutable notify_chan : _chan<task_notification>,
+    ctx : task_context,
+    stack_ptr : *u8
 };
 
+type task_context = {
+    regs : x86_registers,
+    next : *u8
+};
+
+resource rust_task_ptr(task : *rust_task) {
+    rustrt::drop_task(task);
+}
+
+fn get_task_ptr(id : task) -> rust_task_ptr {
+    ret rust_task_ptr(rustrt::get_task_pointer(id));
+}
+
 type task = int;
 type task_id = task;
 
@@ -95,14 +111,16 @@ fn spawn_inner(thunk : -fn() -> (),
     let id = rustrt::new_task();
 
     // the order of arguments are outptr, taskptr, envptr.
-
-    // In LLVM fastcall puts the first two in ecx, edx, and the rest on the
+    // LLVM fastcall puts the first two in ecx, edx, and the rest on the
     // stack.
-    let regs = rustrt::get_task_context(id);
 
     // set up the task pointer
-    let task_ptr = rustrt::get_task_pointer(id);
-    (*regs).edx = cast(task_ptr);
+    let task_ptr = get_task_ptr(id);
+    let regs = ptr::addr_of((**task_ptr).ctx.regs);
+    (*regs).edx = cast(*task_ptr);
+    (*regs).esp = cast((**task_ptr).stack_ptr);
+
+    assert ptr::null() != (**task_ptr).stack_ptr;
 
     let raw_thunk : { code: u32, env: u32 } = cast(thunk);
     (*regs).eip = raw_thunk.code;
@@ -110,8 +128,8 @@ fn spawn_inner(thunk : -fn() -> (),
     // set up notifications if they are enabled.
     alt notify {
       some(c) {
-        (*task_ptr).notify_enabled = 1u8;
-        (*task_ptr).notify_chan = c;
+        (**task_ptr).notify_enabled = 1u8;
+        (**task_ptr).notify_chan = c;
       }
       none {}
     };
@@ -130,7 +148,7 @@ fn spawn_inner(thunk : -fn() -> (),
     // put the return pointer in ecx.
     (*regs).ecx = (*regs).esp + 8u32;
 
-    *tptr = cast(task_ptr);
+    *tptr = cast(*task_ptr);
     *env = raw_thunk.env;
     *ra = rustrt::get_task_trampoline();
 
@@ -139,11 +157,6 @@ fn spawn_inner(thunk : -fn() -> (),
 
     rustrt::leak(thunk);
 
-    // Drop twice because get_task_context and get_task_pounter both bump the
-    // ref count and expect us to free it.
-    rustrt::drop_task(id);
-    rustrt::drop_task(id);
-
     ret id;
 }
 

src/rt/arch/i386/context.cpp

@@ -4,6 +4,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <assert.h>
 
 extern "C" uint32_t CDECL swap_registers(registers_t *oregs,
                                          registers_t *regs)
@@ -11,6 +12,7 @@ extern "C" uint32_t CDECL swap_registers(registers_t *oregs,
 
 context::context()
 {
+    assert((void*)&regs == (void*)this);
 }
 
 void context::swap(context &out)

src/rt/rust_builtin.cpp

@@ -712,7 +712,7 @@ unpin_task(rust_task *task) {
 
 extern "C" CDECL rust_task_id
 get_task_id(rust_task *task) {
-    return task->id;
+    return task->user.id;
 }
 
 extern "C" CDECL rust_task_id
@@ -720,30 +720,16 @@ new_task(rust_task *task) {
     return task->kernel->create_task(task, NULL);
 }
 
-extern "C" CDECL registers_t *
-get_task_context(rust_task *task, rust_task_id id) {
-    rust_task *target = task->kernel->get_task_by_id(id);
-    registers_t *regs = &target->ctx.regs;
-    // This next line is a little dangerous.. It means we can only safely call
-    // this when starting a task.
-    regs->esp = target->rust_sp;
-    return regs;
-}
-
 extern "C" CDECL void
-drop_task(rust_task *task, rust_task_id tid) {
-    rust_task *target = task->kernel->get_task_by_id(tid);
+drop_task(rust_task *task, rust_task *target) {
     if(target) {
         target->deref();
-        // Deref twice because get_task_by_id does once.
-        target->deref();
     }
 }
 
 extern "C" CDECL rust_task *
 get_task_pointer(rust_task *task, rust_task_id id) {
-    rust_task *t = task->kernel->get_task_by_id(id);
-    return t;
+    return task->kernel->get_task_by_id(id);
 }
 
 extern "C" CDECL void

src/rt/rust_kernel.cpp

@@ -154,10 +154,10 @@ rust_kernel::create_task(rust_task *spawner, const char *name) {
     rust_task *t = thread->create_task(spawner, name);
     {
         scoped_lock with(_kernel_lock);
-        t->id = max_id++;
-        task_table.put(t->id, t);
+        t->user.id = max_id++;
+        task_table.put(t->user.id, t);
     }
-    return t->id;
+    return t->user.id;
 }
 
 rust_task *

src/rt/rust_scheduler.cpp

@@ -47,10 +47,10 @@ void
 rust_scheduler::activate(rust_task *task) {
     context ctx;
 
-    task->ctx.next = &ctx;
+    task->user.ctx.next = &ctx;
     DLOG(this, task, "descheduling...");
     lock.unlock();
-    task->ctx.swap(ctx);
+    task->user.ctx.swap(ctx);
     lock.lock();
     DLOG(this, task, "task has returned");
 }
@@ -226,7 +226,7 @@ rust_scheduler::start_main_loop() {
              ", state: %s",
              scheduled_task->name,
              (uintptr_t)scheduled_task,
-             scheduled_task->rust_sp,
+             scheduled_task->user.rust_sp,
              scheduled_task->state->name);
 
         interrupt_flag = 0;
@@ -244,7 +244,7 @@ rust_scheduler::start_main_loop() {
              scheduled_task->name,
              (uintptr_t)scheduled_task,
              scheduled_task->state->name,
-             scheduled_task->rust_sp,
+             scheduled_task->user.rust_sp,
              id);
 
         reap_dead_tasks(id);

src/rt/rust_task.cpp

@@ -57,7 +57,6 @@ rust_task::rust_task(rust_scheduler *sched, rust_task_list *state,
     ref_count(1),
     stk(NULL),
     runtime_sp(0),
-    rust_sp(0),
     gc_alloc_chain(0),
     sched(sched),
     cache(NULL),
@@ -86,7 +85,7 @@ rust_task::rust_task(rust_scheduler *sched, rust_task_list *state,
     user.notify_enabled = 0;
 
     stk = new_stk(sched, this, 0);
-    rust_sp = stk->limit;
+    user.rust_sp = stk->limit;
 }
 
 rust_task::~rust_task()
@@ -99,7 +98,7 @@ rust_task::~rust_task()
             get_chan_by_handle(&user.notify_chan);
         if(target) {
             task_notification msg;
-            msg.id = id;
+            msg.id = user.id;
             msg.result = failed ? tr_failure : tr_success;
 
             target->send(&msg);
@@ -107,7 +106,7 @@ rust_task::~rust_task()
         }
     }
 
-    kernel->release_task_id(id);
+    kernel->release_task_id(user.id);
 
     /* FIXME: tighten this up, there are some more
        assertions that hold at task-lifecycle events. */
@@ -166,7 +165,7 @@ rust_task::start(uintptr_t spawnee_fn,
 
     I(sched, stk->data != NULL);
 
-    char *sp = (char *)rust_sp;
+    char *sp = (char *)user.rust_sp;
 
     sp -= sizeof(spawn_args);
 
@@ -178,7 +177,7 @@ rust_task::start(uintptr_t spawnee_fn,
     void **f = (void **)&a->f;
     *f = (void *)spawnee_fn;
 
-    ctx.call((void *)task_start_wrapper, a, sp);
+    user.ctx.call((void *)task_start_wrapper, a, sp);
 
     this->start();
 }
@@ -213,7 +212,7 @@ rust_task::yield(size_t time_in_us) {
     yield_timer.reset_us(time_in_us);
 
     // Return to the scheduler.
-    ctx.next->swap(ctx);
+    user.ctx.next->swap(user.ctx);
 }
 
 void

src/rt/rust_task.h

@@ -38,8 +38,11 @@ struct gc_alloc {
 // portions of the task structure that are accessible from the standard
 // library. This struct must agree with the std::task::rust_task record.
 struct rust_task_user {
+    rust_task_id id;
     uint8_t notify_enabled;
     chan_handle notify_chan;
+    context ctx;
+    uintptr_t rust_sp;         // Saved sp when not running.
 };
 
 // std::lib::task::task_result
@@ -66,7 +69,6 @@ rust_task : public kernel_owned<rust_task>, rust_cond
     // Fields known to the compiler.
     stk_seg *stk;
     uintptr_t runtime_sp;      // Runtime sp while task running.
-    uintptr_t rust_sp;         // Saved sp when not running.
     gc_alloc *gc_alloc_chain;  // Linked list of GC allocations.
     rust_scheduler *sched;
     rust_crate_cache *cache;
@@ -82,7 +84,6 @@ rust_task : public kernel_owned<rust_task>, rust_cond
     size_t gc_alloc_thresh;
     size_t gc_alloc_accum;
 
-    rust_task_id id;
     rust_port_id next_port_id;
 
     // Keeps track of the last time this task yielded.
@@ -99,8 +100,6 @@ rust_task : public kernel_owned<rust_task>, rust_cond
     // List of tasks waiting for this task to finish.
     array_list<rust_task *> tasks_waiting_to_join;
 
-    context ctx;
-
     // This flag indicates that a worker is either currently running the task
     // or is about to run this task.
     int running_on;

src/rt/rustrt.def.in

@@ -25,7 +25,6 @@ do_gc
 drop_port
 drop_task
 get_port_id
-get_task_context
 get_task_id
 get_task_pointer
 get_task_trampoline