unsafePerformIO thunk will be updated with a stack object
containing the unblockAsyncExceptions_ret frame. Later, when
someone else evaluates this thunk, the blocked exception state is
- not restored, and the result is that unblockAsyncExceptions_ret
- will attempt to unblock exceptions in the current thread, but it'll
- find that the CurrentTSO->blocked_exceptions is NULL. Hence, we
- work around this by checking for NULL in awakenBlockedQueue().
+ not restored.
-------------------------------------------------------------------------- */
INFO_TABLE_RET( stg_unblockAsyncExceptionszh_ret,
0/*framesize*/, 0/*bitmap*/, RET_SMALL )
{
- // Not true: see comments above
- // ASSERT(StgTSO_blocked_exceptions(CurrentTSO) != NULL);
-
- foreign "C" awakenBlockedExceptionQueue(MyCapability() "ptr",
- CurrentTSO "ptr") [R1];
+ CInt r;
StgTSO_flags(CurrentTSO) = StgTSO_flags(CurrentTSO) &
~(TSO_BLOCKEX::I32|TSO_INTERRUPTIBLE::I32);
+ /* Eagerly raise a blocked exception, if there is one */
+ if (StgTSO_blocked_exceptions(CurrentTSO) != END_TSO_QUEUE) {
+ /*
+ * We have to be very careful here, as in killThread#, since
+ * we are about to raise an async exception in the current
+ * thread, which might result in the thread being killed.
+ */
+
+#ifndef REG_R1
+ /*
+ * raiseAsync assumes that the stack is in ThreadRunGHC state,
+ * i.e. with a return address on the top. In unreg mode, the
+ * return value for IO is on top of the return address, so we
+ * need to make a small adjustment here.
+ */
+ Sp_adj(1);
+#endif
+ SAVE_THREAD_STATE();
+ r = foreign "C" maybePerformBlockedException (MyCapability() "ptr",
+ CurrentTSO "ptr") [R1];
+
+ if (r != 0::CInt) {
+ if (StgTSO_what_next(CurrentTSO) == ThreadKilled::I16) {
+ jump stg_threadFinished;
+ } else {
+ LOAD_THREAD_STATE();
+ ASSERT(StgTSO_what_next(CurrentTSO) == ThreadRunGHC::I16);
+ jump %ENTRY_CODE(Sp(0));
+ }
+ }
+#ifndef REG_R1
+ /*
+ * Readjust stack in unregisterised mode if we didn't raise an
+ * exception, see above
+ */
+ else {
+ Sp_adj(-1);
+ }
+#endif
+ }
+
#ifdef REG_R1
Sp_adj(1);
jump %ENTRY_CODE(Sp(0));
INFO_TABLE_RET( stg_blockAsyncExceptionszh_ret,
0/*framesize*/, 0/*bitmap*/, RET_SMALL )
{
- // Not true: see comments above
- // ASSERT(StgTSO_blocked_exceptions(CurrentTSO) == NULL);
-
StgTSO_flags(CurrentTSO) =
StgTSO_flags(CurrentTSO) | TSO_BLOCKEX::I32 | TSO_INTERRUPTIBLE::I32;
unblockAsyncExceptionszh_fast
{
+ CInt r;
+
/* Args: R1 :: IO a */
STK_CHK_GEN( WDS(2), R1_PTR, unblockAsyncExceptionszh_fast);
if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) != 0) {
- foreign "C" awakenBlockedExceptionQueue(MyCapability() "ptr",
- CurrentTSO "ptr") [R1];
+
+ StgTSO_flags(CurrentTSO) = StgTSO_flags(CurrentTSO) &
+ ~(TSO_BLOCKEX::I32|TSO_INTERRUPTIBLE::I32);
+
+ /* Eagerly raise a blocked exception, if there is one */
+ if (StgTSO_blocked_exceptions(CurrentTSO) != END_TSO_QUEUE) {
+ /*
+ * We have to be very careful here, as in killThread#, since
+ * we are about to raise an async exception in the current
+ * thread, which might result in the thread being killed.
+ */
+ SAVE_THREAD_STATE();
+ r = foreign "C" maybePerformBlockedException (MyCapability() "ptr",
+ CurrentTSO "ptr") [R1];
+
+ if (r != 0::CInt) {
+ if (StgTSO_what_next(CurrentTSO) == ThreadKilled::I16) {
+ jump stg_threadFinished;
+ } else {
+ LOAD_THREAD_STATE();
+ ASSERT(StgTSO_what_next(CurrentTSO) == ThreadRunGHC::I16);
+ jump %ENTRY_CODE(Sp(0));
+ }
+ }
+ }
/* avoid growing the stack unnecessarily */
if (Sp(0) == stg_unblockAsyncExceptionszh_ret_info) {
foreign "C" throwToSingleThreaded(MyCapability() "ptr",
target "ptr", exception "ptr")[R1,R2];
if (StgTSO_what_next(CurrentTSO) == ThreadKilled::I16) {
- R1 = ThreadFinished;
- jump StgReturn;
+ jump stg_threadFinished;
} else {
LOAD_THREAD_STATE();
ASSERT(StgTSO_what_next(CurrentTSO) == ThreadRunGHC::I16);
-------------------------------------------------------------------------- */
#ifdef REG_R1
-#define CATCH_FRAME_ENTRY_TEMPLATE(label,ret) \
- label \
- { \
- Sp = Sp + SIZEOF_StgCatchFrame; \
- jump ret; \
- }
-#else
-#define CATCH_FRAME_ENTRY_TEMPLATE(label,ret) \
- label \
- { \
- W_ rval; \
- rval = Sp(0); \
- Sp = Sp + SIZEOF_StgCatchFrame; \
- Sp(0) = rval; \
- jump ret; \
- }
-#endif
-
-#ifdef REG_R1
#define SP_OFF 0
#else
#define SP_OFF 1
#endif
-CATCH_FRAME_ENTRY_TEMPLATE(stg_catch_frame_0_ret,%RET_VEC(Sp(SP_OFF),0))
-CATCH_FRAME_ENTRY_TEMPLATE(stg_catch_frame_1_ret,%RET_VEC(Sp(SP_OFF),1))
-CATCH_FRAME_ENTRY_TEMPLATE(stg_catch_frame_2_ret,%RET_VEC(Sp(SP_OFF),2))
-CATCH_FRAME_ENTRY_TEMPLATE(stg_catch_frame_3_ret,%RET_VEC(Sp(SP_OFF),3))
-CATCH_FRAME_ENTRY_TEMPLATE(stg_catch_frame_4_ret,%RET_VEC(Sp(SP_OFF),4))
-CATCH_FRAME_ENTRY_TEMPLATE(stg_catch_frame_5_ret,%RET_VEC(Sp(SP_OFF),5))
-CATCH_FRAME_ENTRY_TEMPLATE(stg_catch_frame_6_ret,%RET_VEC(Sp(SP_OFF),6))
-CATCH_FRAME_ENTRY_TEMPLATE(stg_catch_frame_7_ret,%RET_VEC(Sp(SP_OFF),7))
-
-#if MAX_VECTORED_RTN > 8
-#error MAX_VECTORED_RTN has changed: please modify stg_catch_frame too.
-#endif
-
#if defined(PROFILING)
#define CATCH_FRAME_BITMAP 7
#define CATCH_FRAME_WORDS 4
INFO_TABLE_RET(stg_catch_frame,
CATCH_FRAME_WORDS, CATCH_FRAME_BITMAP,
- CATCH_FRAME,
- stg_catch_frame_0_ret,
- stg_catch_frame_1_ret,
- stg_catch_frame_2_ret,
- stg_catch_frame_3_ret,
- stg_catch_frame_4_ret,
- stg_catch_frame_5_ret,
- stg_catch_frame_6_ret,
- stg_catch_frame_7_ret)
-CATCH_FRAME_ENTRY_TEMPLATE(,%ENTRY_CODE(Sp(SP_OFF)))
+ CATCH_FRAME)
+#ifdef REG_R1
+ {
+ Sp = Sp + SIZEOF_StgCatchFrame;
+ jump %ENTRY_CODE(Sp(SP_OFF));
+ }
+#else
+ {
+ W_ rval;
+ rval = Sp(0);
+ Sp = Sp + SIZEOF_StgCatchFrame;
+ Sp(0) = rval;
+ jump %ENTRY_CODE(Sp(SP_OFF));
+ }
+#endif
/* -----------------------------------------------------------------------------
* The catch infotable
jump raisezh_fast;
}
+section "data" {
+ no_break_on_exception: W_[1];
+}
+
+INFO_TABLE_RET(stg_raise_ret, 1, 0, RET_SMALL)
+{
+ R1 = Sp(1);
+ Sp = Sp + WDS(2);
+ W_[no_break_on_exception] = 1;
+ jump raisezh_fast;
+}
+
raisezh_fast
{
W_ handler;
- W_ raise_closure;
W_ frame_type;
+ W_ exception;
/* args : R1 :: Exception */
+ exception = R1;
#if defined(PROFILING)
/* Debugging tool: on raising an exception, show where we are. */
/* ToDo: currently this is a hack. Would be much better if
* the info was only displayed for an *uncaught* exception.
*/
- if (RtsFlags_ProfFlags_showCCSOnException(RtsFlags) != 0) {
- foreign "C" fprintCCS_stderr(W_[CCCS] "ptr");
+ if (RtsFlags_ProfFlags_showCCSOnException(RtsFlags) != 0::I32) {
+ foreign "C" fprintCCS_stderr(W_[CCCS] "ptr") [];
}
#endif
-
+
retry_pop_stack:
StgTSO_sp(CurrentTSO) = Sp;
- frame_type = foreign "C" raiseExceptionHelper(BaseReg "ptr", CurrentTSO "ptr", R1 "ptr");
+ frame_type = foreign "C" raiseExceptionHelper(BaseReg "ptr", CurrentTSO "ptr", exception "ptr") [];
Sp = StgTSO_sp(CurrentTSO);
if (frame_type == ATOMICALLY_FRAME) {
/* The exception has reached the edge of a memory transaction. Check that
* the transaction is valid. If not then perhaps the exception should
- * not have been thrown: re-run the transaction */
- W_ trec;
+ * not have been thrown: re-run the transaction. "trec" will either be
+ * a top-level transaction running the atomic block, or a nested
+ * transaction running an invariant check. In the latter case we
+ * abort and de-allocate the top-level transaction that encloses it
+ * as well (we could just abandon its transaction record, but this makes
+ * sure it's marked as aborted and available for re-use). */
+ W_ trec, outer;
W_ r;
trec = StgTSO_trec(CurrentTSO);
- r = foreign "C" stmValidateNestOfTransactions(trec "ptr");
- foreign "C" stmAbortTransaction(MyCapability() "ptr", trec "ptr");
+ r = foreign "C" stmValidateNestOfTransactions(trec "ptr") [];
+ "ptr" outer = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+ foreign "C" stmAbortTransaction(MyCapability() "ptr", trec "ptr") [];
+ foreign "C" stmFreeAbortedTRec(MyCapability() "ptr", trec "ptr") [];
+
+ if (outer != NO_TREC) {
+ foreign "C" stmAbortTransaction(MyCapability() "ptr", outer "ptr") [];
+ foreign "C" stmFreeAbortedTRec(MyCapability() "ptr", outer "ptr") [];
+ }
+
StgTSO_trec(CurrentTSO) = NO_TREC;
if (r != 0) {
// Transaction was valid: continue searching for a catch frame
} else {
// Transaction was not valid: we retry the exception (otherwise continue
// with a further call to raiseExceptionHelper)
- "ptr" trec = foreign "C" stmStartTransaction(MyCapability() "ptr", NO_TREC "ptr");
+ "ptr" trec = foreign "C" stmStartTransaction(MyCapability() "ptr", NO_TREC "ptr") [];
StgTSO_trec(CurrentTSO) = trec;
R1 = StgAtomicallyFrame_code(Sp);
jump stg_ap_v_fast;
}
}
+ // After stripping the stack, see whether we should break here for
+ // GHCi (c.f. the -fbreak-on-exception flag). We do this after
+ // stripping the stack for a reason: we'll be inspecting values in
+ // GHCi, and it helps if all the thunks under evaluation have
+ // already been updated with the exception, rather than being left
+ // as blackholes.
+ if (W_[no_break_on_exception] != 0) {
+ W_[no_break_on_exception] = 0;
+ } else {
+ if (TO_W_(CInt[rts_stop_on_exception]) != 0) {
+ W_ ioAction;
+ // we don't want any further exceptions to be caught,
+ // until GHCi is ready to handle them. This prevents
+ // deadlock if an exception is raised in InteractiveUI,
+ // for exmplae. Perhaps the stop_on_exception flag should
+ // be per-thread.
+ W_[rts_stop_on_exception] = 0;
+ "ptr" ioAction = foreign "C" deRefStablePtr (W_[rts_breakpoint_io_action] "ptr") [];
+ Sp = Sp - WDS(6);
+ Sp(5) = exception;
+ Sp(4) = stg_raise_ret_info;
+ Sp(3) = exception; // the AP_STACK
+ Sp(2) = base_GHCziBase_True_closure; // dummy breakpoint info
+ Sp(1) = base_GHCziBase_True_closure; // True <=> a breakpoint
+ R1 = ioAction;
+ jump stg_ap_pppv_info;
+ }
+ }
+
if (frame_type == STOP_FRAME) {
/*
* We've stripped the entire stack, the thread is now dead.
*/
Sp = CurrentTSO + TSO_OFFSET_StgTSO_stack
+ WDS(TO_W_(StgTSO_stack_size(CurrentTSO))) - WDS(2);
- Sp(1) = R1; /* save the exception */
+ Sp(1) = exception; /* save the exception */
Sp(0) = stg_enter_info; /* so that GC can traverse this stack */
StgTSO_what_next(CurrentTSO) = ThreadKilled::I16;
SAVE_THREAD_STATE(); /* inline! */
- /* The return code goes in BaseReg->rRet, and BaseReg is returned in R1 */
- StgRegTable_rRet(BaseReg) = ThreadFinished;
- R1 = BaseReg;
-
- jump StgReturn;
+ jump stg_threadFinished;
}
/* Ok, Sp points to the enclosing CATCH_FRAME or CATCH_STM_FRAME. Pop everything
* If exceptions were unblocked, arrange that they are unblocked
* again after executing the handler by pushing an
* unblockAsyncExceptions_ret stack frame.
+ *
+ * If we've reached an STM catch frame then roll back the nested
+ * transaction we were using.
*/
W_ frame;
frame = Sp;
Sp(0) = stg_unblockAsyncExceptionszh_ret_info;
}
} else {
+ W_ trec, outer;
+ trec = StgTSO_trec(CurrentTSO);
+ "ptr" outer = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+ foreign "C" stmAbortTransaction(MyCapability() "ptr", trec "ptr") [];
+ foreign "C" stmFreeAbortedTRec(MyCapability() "ptr", trec "ptr") [];
+ StgTSO_trec(CurrentTSO) = outer;
Sp = Sp + SIZEOF_StgCatchSTMFrame;
}
* token as arguments.
*/
Sp_adj(-1);
- Sp(0) = R1;
+ Sp(0) = exception;
R1 = handler;
Sp_adj(-1);
TICK_UNKNOWN_CALL();