rts: Claim AP_STACK before adjusting Sp
[ghc.git] / rts / RtsAPI.c
index 6e66218..533c0c4 100644 (file)
 #include "Schedule.h"
 #include "Capability.h"
 #include "Stable.h"
+#include "Threads.h"
 #include "Weak.h"
 
 /* ----------------------------------------------------------------------------
    Building Haskell objects from C datatypes.
 
    TODO: Currently this code does not tag created pointers,
-         however it is not unsafe (the contructor code will do it)
+         however it is not unsafe (the constructor code will do it)
          just inefficient.
    ------------------------------------------------------------------------- */
 HaskellObj
@@ -198,7 +199,10 @@ rts_apply (Capability *cap, HaskellObj f, HaskellObj arg)
     StgThunk *ap;
 
     ap = (StgThunk *)allocate(cap,sizeofW(StgThunk) + 2);
-    SET_HDR(ap, (StgInfoTable *)&stg_ap_2_upd_info, CCS_SYSTEM);
+    // Here we don't want to use CCS_SYSTEM, because it's a hidden cost centre,
+    // and evaluating Haskell code under a hidden cost centre leads to
+    // confusing profiling output. (#7753)
+    SET_HDR(ap, (StgInfoTable *)&stg_ap_2_upd_info, CCS_MAIN);
     ap->payload[0] = f;
     ap->payload[1] = arg;
     return (StgClosure *)ap;
@@ -360,13 +364,13 @@ rts_getFunPtr (HaskellObj p)
 HsBool
 rts_getBool (HaskellObj p)
 {
-    StgInfoTable *info;
+    const StgInfoTable *info;
 
-    info = get_itbl((StgClosure *)UNTAG_CLOSURE(p));
+    info = get_itbl((const StgClosure *)UNTAG_CONST_CLOSURE(p));
     if (info->srt_bitmap == 0) { // srt_bitmap is the constructor tag
-       return 0;
+        return 0;
     } else {
-       return 1;
+        return 1;
     }
 }
 
@@ -375,12 +379,12 @@ rts_getBool (HaskellObj p)
    -------------------------------------------------------------------------- */
 
 INLINE_HEADER void pushClosure   (StgTSO *tso, StgWord c) {
-  tso->sp--;
-  tso->sp[0] = (W_) c;
+  tso->stackobj->sp--;
+  tso->stackobj->sp[0] = (W_) c;
 }
 
 StgTSO *
-createGenThread (Capability *cap, nat stack_size,  StgClosure *closure)
+createGenThread (Capability *cap, W_ stack_size,  StgClosure *closure)
 {
   StgTSO *t;
   t = createThread (cap, stack_size);
@@ -390,11 +394,10 @@ createGenThread (Capability *cap, nat stack_size,  StgClosure *closure)
 }
 
 StgTSO *
-createIOThread (Capability *cap, nat stack_size,  StgClosure *closure)
+createIOThread (Capability *cap, W_ stack_size,  StgClosure *closure)
 {
   StgTSO *t;
   t = createThread (cap, stack_size);
-  pushClosure(t, (W_)&stg_noforceIO_info);
   pushClosure(t, (W_)&stg_ap_v_info);
   pushClosure(t, (W_)closure);
   pushClosure(t, (W_)&stg_enter_info);
@@ -407,7 +410,7 @@ createIOThread (Capability *cap, nat stack_size,  StgClosure *closure)
  */
 
 StgTSO *
-createStrictIOThread(Capability *cap, nat stack_size,  StgClosure *closure)
+createStrictIOThread(Capability *cap, W_ stack_size,  StgClosure *closure)
 {
   StgTSO *t;
   t = createThread(cap, stack_size);
@@ -422,36 +425,68 @@ createStrictIOThread(Capability *cap, nat stack_size,  StgClosure *closure)
    Evaluating Haskell expressions
    ------------------------------------------------------------------------- */
 
-Capability *
-rts_eval (Capability *cap, HaskellObj p, /*out*/HaskellObj *ret)
+void rts_eval (/* inout */ Capability **cap,
+               /* in    */ HaskellObj p,
+               /* out */   HaskellObj *ret)
 {
     StgTSO *tso;
-    
-    tso = createGenThread(cap, RtsFlags.GcFlags.initialStkSize, p);
-    return scheduleWaitThread(tso,ret,cap);
+
+    tso = createGenThread(*cap, RtsFlags.GcFlags.initialStkSize, p);
+    scheduleWaitThread(tso,ret,cap);
 }
 
-Capability *
-rts_eval_ (Capability *cap, HaskellObj p, unsigned int stack_size, 
-          /*out*/HaskellObj *ret)
+void rts_eval_ (/* inout */ Capability **cap,
+                /* in    */ HaskellObj p,
+                /* in    */ unsigned int stack_size,
+                /* out   */ HaskellObj *ret)
 {
     StgTSO *tso;
 
-    tso = createGenThread(cap, stack_size, p);
-    return scheduleWaitThread(tso,ret,cap);
+    tso = createGenThread(*cap, stack_size, p);
+    scheduleWaitThread(tso,ret,cap);
 }
 
 /*
  * rts_evalIO() evaluates a value of the form (IO a), forcing the action's
  * result to WHNF before returning.
  */
-Capability *
-rts_evalIO (Capability *cap, HaskellObj p, /*out*/HaskellObj *ret)
+void rts_evalIO (/* inout */ Capability **cap,
+                 /* in    */ HaskellObj p,
+                 /* out */   HaskellObj *ret)
 {
-    StgTSO* tso; 
-    
-    tso = createStrictIOThread(cap, RtsFlags.GcFlags.initialStkSize, p);
-    return scheduleWaitThread(tso,ret,cap);
+    StgTSO* tso;
+
+    tso = createStrictIOThread(*cap, RtsFlags.GcFlags.initialStkSize, p);
+    scheduleWaitThread(tso,ret,cap);
+}
+
+/*
+ * rts_evalStableIOMain() is suitable for calling main Haskell thread
+ * stored in (StablePtr (IO a)) it calls rts_evalStableIO but wraps
+ * function in GHC.TopHandler.runMainIO that installs top_handlers.
+ * See Trac #12903.
+ */
+void rts_evalStableIOMain(/* inout */ Capability **cap,
+                          /* in    */ HsStablePtr s,
+                          /* out   */ HsStablePtr *ret)
+{
+    StgTSO* tso;
+    StgClosure *p, *r, *w;
+    SchedulerStatus stat;
+
+    p = (StgClosure *)deRefStablePtr(s);
+    w = rts_apply(*cap, &base_GHCziTopHandler_runMainIO_closure, p);
+    tso = createStrictIOThread(*cap, RtsFlags.GcFlags.initialStkSize, w);
+    // async exceptions are always blocked by default in the created
+    // thread.  See #1048.
+    tso->flags |= TSO_BLOCKEX | TSO_INTERRUPTIBLE;
+    scheduleWaitThread(tso,&r,cap);
+    stat = rts_getSchedStatus(*cap);
+
+    if (stat == Success && ret != NULL) {
+        ASSERT(r != NULL);
+        *ret = getStablePtr((StgPtr)r);
+    }
 }
 
 /*
@@ -460,49 +495,50 @@ rts_evalIO (Capability *cap, HaskellObj p, /*out*/HaskellObj *ret)
  * action's result to WHNF before returning.  The result is returned
  * in a StablePtr.
  */
-Capability *
-rts_evalStableIO (Capability *cap, HsStablePtr s, /*out*/HsStablePtr *ret)
+void rts_evalStableIO (/* inout */ Capability **cap,
+                       /* in    */ HsStablePtr s,
+                       /* out */   HsStablePtr *ret)
 {
     StgTSO* tso;
     StgClosure *p, *r;
     SchedulerStatus stat;
-    
+
     p = (StgClosure *)deRefStablePtr(s);
-    tso = createStrictIOThread(cap, RtsFlags.GcFlags.initialStkSize, p);
+    tso = createStrictIOThread(*cap, RtsFlags.GcFlags.initialStkSize, p);
     // async exceptions are always blocked by default in the created
     // thread.  See #1048.
     tso->flags |= TSO_BLOCKEX | TSO_INTERRUPTIBLE;
-    cap = scheduleWaitThread(tso,&r,cap);
-    stat = rts_getSchedStatus(cap);
+    scheduleWaitThread(tso,&r,cap);
+    stat = rts_getSchedStatus(*cap);
 
     if (stat == Success && ret != NULL) {
-       ASSERT(r != NULL);
-       *ret = getStablePtr((StgPtr)r);
+        ASSERT(r != NULL);
+        *ret = getStablePtr((StgPtr)r);
     }
-
-    return cap;
 }
 
 /*
  * Like rts_evalIO(), but doesn't force the action's result.
  */
-Capability *
-rts_evalLazyIO (Capability *cap, HaskellObj p, /*out*/HaskellObj *ret)
+void rts_evalLazyIO (/* inout */ Capability **cap,
+                     /* in    */ HaskellObj p,
+                     /* out */   HaskellObj *ret)
 {
     StgTSO *tso;
 
-    tso = createIOThread(cap, RtsFlags.GcFlags.initialStkSize, p);
-    return scheduleWaitThread(tso,ret,cap);
+    tso = createIOThread(*cap, RtsFlags.GcFlags.initialStkSize, p);
+    scheduleWaitThread(tso,ret,cap);
 }
 
-Capability *
-rts_evalLazyIO_ (Capability *cap, HaskellObj p, unsigned int stack_size, 
-                /*out*/HaskellObj *ret)
+void rts_evalLazyIO_ (/* inout */ Capability **cap,
+                      /* in    */ HaskellObj p,
+                      /* in    */ unsigned int stack_size,
+                      /* out   */ HaskellObj *ret)
 {
     StgTSO *tso;
 
-    tso = createIOThread(cap, stack_size, p);
-    return scheduleWaitThread(tso,ret,cap);
+    tso = createIOThread(*cap, stack_size, p);
+    scheduleWaitThread(tso,ret,cap);
 }
 
 /* Convenience function for decoding the returned status. */
@@ -510,26 +546,35 @@ rts_evalLazyIO_ (Capability *cap, HaskellObj p, unsigned int stack_size,
 void
 rts_checkSchedStatus (char* site, Capability *cap)
 {
-    SchedulerStatus rc = cap->running_task->stat;
+    SchedulerStatus rc = cap->running_task->incall->rstat;
     switch (rc) {
     case Success:
-       return;
+        return;
     case Killed:
-       errorBelch("%s: uncaught exception",site);
-       stg_exit(EXIT_FAILURE);
+        errorBelch("%s: uncaught exception",site);
+        stg_exit(EXIT_FAILURE);
     case Interrupted:
-       errorBelch("%s: interrupted", site);
-       stg_exit(EXIT_FAILURE);
+        errorBelch("%s: interrupted", site);
+#if defined(THREADED_RTS)
+        // The RTS is shutting down, and the process will probably
+        // soon exit.  We don't want to preempt the shutdown
+        // by exiting the whole process here, so we just terminate the
+        // current thread.  Don't forget to release the cap first though.
+        rts_unlock(cap);
+        shutdownThread();
+#else
+        stg_exit(EXIT_FAILURE);
+#endif
     default:
-       errorBelch("%s: Return code (%d) not ok",(site),(rc));  
-       stg_exit(EXIT_FAILURE);
+        errorBelch("%s: Return code (%d) not ok",(site),(rc));
+        stg_exit(EXIT_FAILURE);
     }
 }
 
 SchedulerStatus
 rts_getSchedStatus (Capability *cap)
 {
-    return cap->running_task->stat;
+    return cap->running_task->incall->rstat;
 }
 
 Capability *
@@ -538,7 +583,9 @@ rts_lock (void)
     Capability *cap;
     Task *task;
 
-    if (running_finalizers) {
+    task = newBoundTask();
+
+    if (task->running_finalizers) {
         errorBelch("error: a C finalizer called back into Haskell.\n"
                    "   This was previously allowed, but is disallowed in GHC 6.10.2 and later.\n"
                    "   To create finalizers that may call back into Haskell, use\n"
@@ -546,10 +593,16 @@ rts_lock (void)
         stg_exit(EXIT_FAILURE);
     }
 
-    task = newBoundTask();
-
     cap = NULL;
-    waitForReturnCapability(&cap, task);
+    waitForCapability(&cap, task);
+
+    if (task->incall->prev_stack == NULL) {
+      // This is a new outermost call from C into Haskell land.
+      // Until the corresponding call to rts_unlock, this task
+      // is doing work on behalf of the RTS.
+      traceTaskCreate(task, cap);
+    }
+
     return (Capability *)cap;
 }
 
@@ -578,9 +631,96 @@ rts_unlock (Capability *cap)
     // random point in the future, which causes problems for
     // freeTaskManager().
     ACQUIRE_LOCK(&cap->lock);
-    releaseCapability_(cap,rtsFalse);
+    releaseCapability_(cap,false);
 
     // Finally, we can release the Task to the free list.
     boundTaskExiting(task);
     RELEASE_LOCK(&cap->lock);
+
+    if (task->incall == NULL) {
+      // This is the end of an outermost call from C into Haskell land.
+      // From here on, the task goes back to C land and we should not count
+      // it as doing work on behalf of the RTS.
+      traceTaskDelete(task);
+    }
+}
+
+void rts_done (void)
+{
+    freeMyTask();
+}
+
+/* -----------------------------------------------------------------------------
+   tryPutMVar from outside Haskell
+
+   The C call
+
+      hs_try_putmvar(cap, mvar)
+
+   is equivalent to the Haskell call
+
+      tryPutMVar mvar ()
+
+   but it is
+
+     * non-blocking: takes a bounded, short, amount of time
+     * asynchronous: the actual putMVar may be performed after the
+       call returns.  That's why hs_try_putmvar() doesn't return a
+       result to say whether the put succeeded.
+
+   NOTE: this call transfers ownership of the StablePtr to the RTS, which will
+   free it after the tryPutMVar has taken place.  The reason is that otherwise,
+   it would be very difficult for the caller to arrange to free the StablePtr
+   in all circumstances.
+
+   For more details, see the section "Waking up Haskell threads from C" in the
+   User's Guide.
+   -------------------------------------------------------------------------- */
+
+void hs_try_putmvar (/* in */ int capability,
+                     /* in */ HsStablePtr mvar)
+{
+    Task *task = getTask();
+    Capability *cap;
+
+    if (capability < 0) {
+        capability = task->preferred_capability;
+        if (capability < 0) {
+            capability = 0;
+        }
+    }
+    cap = capabilities[capability % enabled_capabilities];
+
+#if !defined(THREADED_RTS)
+
+    performTryPutMVar(cap, (StgMVar*)deRefStablePtr(mvar), Unit_closure);
+    freeStablePtr(mvar);
+
+#else
+
+    ACQUIRE_LOCK(&cap->lock);
+    // If the capability is free, we can perform the tryPutMVar immediately
+    if (cap->running_task == NULL) {
+        cap->running_task = task;
+        task->cap = cap;
+        RELEASE_LOCK(&cap->lock);
+
+        performTryPutMVar(cap, (StgMVar*)deRefStablePtr(mvar), Unit_closure);
+
+        freeStablePtr(mvar);
+
+        // Wake up the capability, which will start running the thread that we
+        // just awoke (if there was one).
+        releaseCapability(cap);
+    } else {
+        PutMVar *p = stgMallocBytes(sizeof(PutMVar),"hs_try_putmvar");
+        // We cannot deref the StablePtr if we don't have a capability,
+        // so we have to store it and deref it later.
+        p->mvar = mvar;
+        p->link = cap->putMVars;
+        cap->putMVars = p;
+        RELEASE_LOCK(&cap->lock);
+    }
+
+#endif
 }