Commit 93d2b952 authored by simonmar's avatar simonmar
Browse files

[project @ 2002-02-15 14:49:08 by simonmar]

Fix bugs in async exception raising: instead of trying to build an
application of the exception handler to the exception directly, just
leave a THUNK(raise,exception) on top of the CATCH_FRAME ready to
trigger the next time this thread is run.

This avoids two problems: the PAP we were using before wasn't really a
PAP, which broke some assumptions elsewhere (c.f. PAP_ENTRY:
CATCH_FRAME failure), and there was also some duplication between
raiseAsync and raisezh_fast due to the fact that we were attempting to
do the raising directly.
parent 5b50dc39
/* ---------------------------------------------------------------------------
* $Id: Schedule.c,v 1.124 2002/02/15 07:50:36 sof Exp $
* $Id: Schedule.c,v 1.125 2002/02/15 14:49:08 simonmar Exp $
*
* (c) The GHC Team, 1998-2000
*
......@@ -3072,51 +3072,30 @@ raiseAsync(StgTSO *tso, StgClosure *exception)
StgAP_UPD * ap;
/* If we find a CATCH_FRAME, and we've got an exception to raise,
* then build PAP(handler,exception,realworld#), and leave it on
* top of the stack ready to enter.
* then build the THUNK raise(exception), and leave it on
* top of the CATCH_FRAME ready to enter.
*/
if (get_itbl(su)->type == CATCH_FRAME && exception != NULL) {
StgCatchFrame *cf = (StgCatchFrame *)su;
StgClosure *raise;
/* we've got an exception to raise, so let's pass it to the
* handler in this frame.
*/
ap = (StgAP_UPD *)allocate(sizeofW(StgPAP) + 2);
TICK_ALLOC_UPD_PAP(3,0);
SET_HDR(ap,&stg_PAP_info,cf->header.prof.ccs);
ap->n_args = 2;
ap->fun = cf->handler; /* :: Exception -> IO a */
ap->payload[0] = exception;
ap->payload[1] = ARG_TAG(0); /* realworld token */
/* throw away the stack from Sp up to and including the
* CATCH_FRAME.
*/
sp = (P_)su + sizeofW(StgCatchFrame) - 1;
tso->su = cf->link;
/* Restore the blocked/unblocked state for asynchronous exceptions
* at the CATCH_FRAME.
*
* If exceptions were unblocked at the catch, arrange that they
* are unblocked again after executing the handler by pushing an
* unblockAsyncExceptions_ret stack frame.
*/
if (!cf->exceptions_blocked) {
*(sp--) = (W_)&stg_unblockAsyncExceptionszh_ret_info;
}
/* Ensure that async exceptions are blocked when running the handler.
raise = (StgClosure *)allocate(sizeofW(StgClosure)+1);
TICK_ALLOC_SE_THK(1,0);
SET_HDR(raise,&stg_raise_info,cf->header.prof.ccs);
raise->payload[0] = exception;
/* throw away the stack from Sp up to the CATCH_FRAME.
*/
if (tso->blocked_exceptions == NULL) {
tso->blocked_exceptions = END_TSO_QUEUE;
}
/* Put the newly-built PAP on top of the stack, ready to execute
sp = (P_)su - 1;
/* Put the newly-built THUNK on top of the stack, ready to execute
* when the thread restarts.
*/
sp[0] = (W_)ap;
sp[0] = (W_)raise;
tso->sp = sp;
tso->su = su;
tso->what_next = ThreadEnterGHC;
IF_DEBUG(sanity, checkTSO(tso));
return;
......
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