#include "Cmm.h"
#include "RaiseAsync.h"
+import CLOSURE ghczmprim_GHCziTypes_True_closure;
+
/* -----------------------------------------------------------------------------
Exception Primitives
A thread can request that asynchronous exceptions not be delivered
- ("blocked") for the duration of an I/O computation. The primitive
-
- blockAsyncExceptions# :: IO a -> IO a
+ ("masked") for the duration of an I/O computation. The primitives
+
+ maskAsyncExceptions# :: IO a -> IO a
+
+ and
- is used for this purpose. During a blocked section, asynchronous
- exceptions may be unblocked again temporarily:
+ maskUninterruptible# :: IO a -> IO a
- unblockAsyncExceptions# :: IO a -> IO a
+ are used for this purpose. During a masked section, asynchronous
+ exceptions may be unmasked again temporarily:
- Furthermore, asynchronous exceptions are blocked automatically during
- the execution of an exception handler. Both of these primitives
+ unmaskAsyncExceptions# :: IO a -> IO a
+
+ Furthermore, asynchronous exceptions are masked automatically during
+ the execution of an exception handler. All three of these primitives
leave a continuation on the stack which reverts to the previous
- state (blocked or unblocked) on exit.
+ state (masked interruptible, masked non-interruptible, or unmasked)
+ on exit.
A thread which wants to raise an exception in another thread (using
killThread#) must block until the target thread is ready to receive
- it. The action of unblocking exceptions in a thread will release all
+ it. The action of unmasking exceptions in a thread will release all
the threads waiting to deliver exceptions to that thread.
NB. there's a bug in here. If a thread is inside an
- unsafePerformIO, and inside blockAsyncExceptions# (there is an
- unblockAsyncExceptions_ret on the stack), and it is blocked in an
+ unsafePerformIO, and inside maskAsyncExceptions# (there is an
+ unmaskAsyncExceptions_ret on the stack), and it is blocked in an
interruptible operation, and it receives an exception, then the
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().
+ containing the unmaskAsyncExceptions_ret frame. Later, when
+ someone else evaluates this thunk, the original masking state is
+ not restored.
-------------------------------------------------------------------------- */
-INFO_TABLE_RET( stg_unblockAsyncExceptionszh_ret,
- 0/*framesize*/, 0/*bitmap*/, RET_SMALL )
+
+INFO_TABLE_RET(stg_unmaskAsyncExceptionszh_ret, RET_SMALL, W_ info_ptr)
+ /* explicit stack */
{
- // Not true: see comments above
- // ASSERT(StgTSO_blocked_exceptions(CurrentTSO) != NULL);
+ unwind Sp = Sp + WDS(1);
+ CInt r;
+
+ P_ ret;
+ ret = R1;
+
+ StgTSO_flags(CurrentTSO) = %lobits32(
+ TO_W_(StgTSO_flags(CurrentTSO)) & ~(TSO_BLOCKEX|TSO_INTERRUPTIBLE));
+
+ /* Eagerly raise a masked exception, if there is one */
+ if (StgTSO_blocked_exceptions(CurrentTSO) != END_TSO_QUEUE) {
+
+ STK_CHK_P_LL (WDS(2), stg_unmaskAsyncExceptionszh_ret_info, R1);
+ /*
+ * 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.
+ */
+ Sp_adj(-2);
+ Sp(1) = ret;
+ Sp(0) = stg_ret_p_info;
+ SAVE_THREAD_STATE();
+ (r) = ccall maybePerformBlockedException (MyCapability() "ptr",
+ CurrentTSO "ptr");
+ 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);
+ R1 = ret;
+ jump %ENTRY_CODE(Sp(0)) [R1];
+ }
+ }
+ else {
+ /*
+ the thread might have been removed from the
+ blocked_exception list by someone else in the meantime.
+ Just restore the stack pointer and continue.
+ */
+ Sp_adj(2);
+ }
+ }
- foreign "C" awakenBlockedExceptionQueue(MyCapability() "ptr",
- CurrentTSO "ptr") [R1];
+ Sp_adj(1);
+ R1 = ret;
+ jump %ENTRY_CODE(Sp(0)) [R1];
+}
- StgTSO_flags(CurrentTSO) = StgTSO_flags(CurrentTSO) &
- ~(TSO_BLOCKEX::I32|TSO_INTERRUPTIBLE::I32);
+INFO_TABLE_RET(stg_maskAsyncExceptionszh_ret, RET_SMALL, W_ info_ptr)
+ return (P_ ret)
+{
+ unwind Sp = Sp + WDS(1);
+ StgTSO_flags(CurrentTSO) =
+ %lobits32(
+ TO_W_(StgTSO_flags(CurrentTSO))
+ | TSO_BLOCKEX | TSO_INTERRUPTIBLE
+ );
+
+ return (ret);
+}
-#ifdef REG_R1
- Sp_adj(1);
- jump %ENTRY_CODE(Sp(0));
-#else
- Sp(1) = Sp(0);
- Sp_adj(1);
- jump %ENTRY_CODE(Sp(1));
-#endif
+INFO_TABLE_RET(stg_maskUninterruptiblezh_ret, RET_SMALL, W_ info_ptr)
+ return (P_ ret)
+{
+ unwind Sp = Sp + WDS(1);
+ StgTSO_flags(CurrentTSO) =
+ %lobits32(
+ (TO_W_(StgTSO_flags(CurrentTSO))
+ | TSO_BLOCKEX)
+ & ~TSO_INTERRUPTIBLE
+ );
+
+ return (ret);
}
-INFO_TABLE_RET( stg_blockAsyncExceptionszh_ret,
- 0/*framesize*/, 0/*bitmap*/, RET_SMALL )
+stg_maskAsyncExceptionszh /* explicit stack */
{
- // Not true: see comments above
- // ASSERT(StgTSO_blocked_exceptions(CurrentTSO) == NULL);
+ /* Args: R1 :: IO a */
+ STK_CHK_P_LL (WDS(1)/* worst case */, stg_maskAsyncExceptionszh, R1);
- StgTSO_flags(CurrentTSO) =
- StgTSO_flags(CurrentTSO) | TSO_BLOCKEX::I32 | TSO_INTERRUPTIBLE::I32;
+ if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) == 0) {
+ /* avoid growing the stack unnecessarily */
+ if (Sp(0) == stg_maskAsyncExceptionszh_ret_info) {
+ Sp_adj(1);
+ } else {
+ Sp_adj(-1);
+ Sp(0) = stg_unmaskAsyncExceptionszh_ret_info;
+ }
+ } else {
+ if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_INTERRUPTIBLE) == 0) {
+ Sp_adj(-1);
+ Sp(0) = stg_maskUninterruptiblezh_ret_info;
+ }
+ }
-#ifdef REG_R1
- Sp_adj(1);
- jump %ENTRY_CODE(Sp(0));
-#else
- Sp(1) = Sp(0);
- Sp_adj(1);
- jump %ENTRY_CODE(Sp(1));
-#endif
+ StgTSO_flags(CurrentTSO) = %lobits32(
+ TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX | TSO_INTERRUPTIBLE);
+
+ TICK_UNKNOWN_CALL();
+ TICK_SLOW_CALL_fast_v();
+ jump stg_ap_v_fast [R1];
}
-blockAsyncExceptionszh_fast
+stg_maskUninterruptiblezh /* explicit stack */
{
/* Args: R1 :: IO a */
- STK_CHK_GEN( WDS(2)/* worst case */, R1_PTR, blockAsyncExceptionszh_fast);
+ STK_CHK_P_LL (WDS(1)/* worst case */, stg_maskUninterruptiblezh, R1);
if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) == 0) {
-
- StgTSO_flags(CurrentTSO) =
- StgTSO_flags(CurrentTSO) | TSO_BLOCKEX::I32 | TSO_INTERRUPTIBLE::I32;
-
- /* avoid growing the stack unnecessarily */
- if (Sp(0) == stg_blockAsyncExceptionszh_ret_info) {
- Sp_adj(1);
- } else {
- Sp_adj(-1);
- Sp(0) = stg_unblockAsyncExceptionszh_ret_info;
- }
+ /* avoid growing the stack unnecessarily */
+ if (Sp(0) == stg_maskUninterruptiblezh_ret_info) {
+ Sp_adj(1);
+ } else {
+ Sp_adj(-1);
+ Sp(0) = stg_unmaskAsyncExceptionszh_ret_info;
+ }
+ } else {
+ if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_INTERRUPTIBLE) != 0) {
+ Sp_adj(-1);
+ Sp(0) = stg_maskAsyncExceptionszh_ret_info;
+ }
}
+
+ StgTSO_flags(CurrentTSO) = %lobits32(
+ (TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX) & ~TSO_INTERRUPTIBLE);
+
TICK_UNKNOWN_CALL();
- TICK_SLOW_CALL_v();
- jump stg_ap_v_fast;
+ TICK_SLOW_CALL_fast_v();
+ jump stg_ap_v_fast [R1];
}
-unblockAsyncExceptionszh_fast
+stg_unmaskAsyncExceptionszh /* explicit stack */
{
+ CInt r;
+ W_ level;
+
/* Args: R1 :: IO a */
- STK_CHK_GEN( WDS(2), R1_PTR, unblockAsyncExceptionszh_fast);
-
- if (TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) {
- foreign "C" awakenBlockedExceptionQueue(MyCapability() "ptr",
- CurrentTSO "ptr") [R1];
-
- /* avoid growing the stack unnecessarily */
- if (Sp(0) == stg_unblockAsyncExceptionszh_ret_info) {
- Sp_adj(1);
- } else {
- Sp_adj(-1);
- Sp(0) = stg_blockAsyncExceptionszh_ret_info;
- }
+ P_ io;
+ io = R1;
+
+ STK_CHK_P_LL (WDS(4), stg_unmaskAsyncExceptionszh, io);
+ /* 4 words: one for the unmask frame, 3 for setting up the
+ * stack to call maybePerformBlockedException() below.
+ */
+
+ /* If exceptions are already unmasked, there's nothing to do */
+ if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) != 0) {
+
+ /* avoid growing the stack unnecessarily */
+ if (Sp(0) == stg_unmaskAsyncExceptionszh_ret_info) {
+ Sp_adj(1);
+ } else {
+ Sp_adj(-1);
+ if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_INTERRUPTIBLE) != 0) {
+ Sp(0) = stg_maskAsyncExceptionszh_ret_info;
+ } else {
+ Sp(0) = stg_maskUninterruptiblezh_ret_info;
+ }
+ }
+
+ StgTSO_flags(CurrentTSO) = %lobits32(
+ TO_W_(StgTSO_flags(CurrentTSO)) & ~(TSO_BLOCKEX|TSO_INTERRUPTIBLE));
+
+ /* Eagerly raise a masked 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.
+ *
+ * Now, if we are to raise an exception in the current
+ * thread, there might be an update frame above us on the
+ * stack due to unsafePerformIO. Hence, the stack must
+ * make sense, because it is about to be snapshotted into
+ * an AP_STACK.
+ */
+ Sp_adj(-3);
+ Sp(2) = stg_ap_v_info;
+ Sp(1) = io;
+ Sp(0) = stg_enter_info;
+
+ SAVE_THREAD_STATE();
+ (r) = ccall maybePerformBlockedException (MyCapability() "ptr",
+ CurrentTSO "ptr");
+
+ 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);
+ R1 = io;
+ jump %ENTRY_CODE(Sp(0)) [R1];
+ }
+ } else {
+ /* we'll just call R1 directly, below */
+ Sp_adj(3);
+ }
+ }
+
}
TICK_UNKNOWN_CALL();
- TICK_SLOW_CALL_v();
- jump stg_ap_v_fast;
+ TICK_SLOW_CALL_fast_v();
+ R1 = io;
+ jump stg_ap_v_fast [R1];
}
-killThreadzh_fast
+stg_getMaskingStatezh ()
{
- /* args: R1 = TSO to kill, R2 = Exception */
+ /* args: none */
+ /*
+ returns: 0 == unmasked,
+ 1 == masked, non-interruptible,
+ 2 == masked, interruptible
+ */
+ return (((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) != 0) +
+ ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_INTERRUPTIBLE) != 0));
+}
+stg_killThreadzh (P_ target, P_ exception)
+{
W_ why_blocked;
- W_ target;
- W_ exception;
-
- target = R1;
- exception = R2;
-
- STK_CHK_GEN( WDS(3), R1_PTR | R2_PTR, killThreadzh_fast);
- /*
+ /* Needs 3 words because throwToSingleThreaded uses some stack */
+ STK_CHK_PP (WDS(3), stg_killThreadzh, target, exception);
+ /* We call allocate in throwTo(), so better check for GC */
+ MAYBE_GC_PP (stg_killThreadzh, target, exception);
+
+ /*
* We might have killed ourselves. In which case, better be *very*
* careful. If the exception killed us, then return to the scheduler.
* If the exception went to a catch frame, we'll just continue from
* the handler.
*/
if (target == CurrentTSO) {
- SAVE_THREAD_STATE();
- /* ToDo: what if the current thread is blocking exceptions? */
- foreign "C" throwToSingleThreaded(MyCapability() "ptr",
- target "ptr", exception "ptr")[R1,R2];
- if (StgTSO_what_next(CurrentTSO) == ThreadKilled::I16) {
- R1 = ThreadFinished;
- jump StgReturn;
- } else {
- LOAD_THREAD_STATE();
- ASSERT(StgTSO_what_next(CurrentTSO) == ThreadRunGHC::I16);
- jump %ENTRY_CODE(Sp(0));
- }
+ /*
+ * So what should happen if a thread calls "throwTo self" inside
+ * unsafePerformIO, and later the closure is evaluated by another
+ * thread? Presumably it should behave as if throwTo just returned,
+ * and then continue from there. See #3279, #3288. This is what
+ * happens: on resumption, we will just jump to the next frame on
+ * the stack, which is the return point for stg_killThreadzh.
+ */
+ R1 = target;
+ R2 = exception;
+ jump stg_killMyself [R1,R2];
} else {
- W_ out;
- W_ retcode;
- out = BaseReg + OFFSET_StgRegTable_rmp_tmp_w;
-
- retcode = foreign "C" throwTo(MyCapability() "ptr",
- CurrentTSO "ptr",
- target "ptr",
- exception "ptr",
- out "ptr") [R1,R2];
-
- switch [THROWTO_SUCCESS .. THROWTO_BLOCKED] (retcode) {
-
- case THROWTO_SUCCESS: {
- jump %ENTRY_CODE(Sp(0));
- }
-
- case THROWTO_BLOCKED: {
- R3 = W_[out];
- // we must block, and call throwToReleaseTarget() before returning
- jump stg_block_throwto;
- }
- }
+ W_ msg;
+
+ ("ptr" msg) = ccall throwTo(MyCapability() "ptr",
+ CurrentTSO "ptr",
+ target "ptr",
+ exception "ptr");
+
+ if (msg == NULL) {
+ return ();
+ } else {
+ StgTSO_why_blocked(CurrentTSO) = BlockedOnMsgThrowTo;
+ StgTSO_block_info(CurrentTSO) = msg;
+ // we must block, and unlock the message before returning
+ jump stg_block_throwto (target, exception);
+ }
+ }
+}
+
+/*
+ * We must switch into low-level Cmm in order to raise an exception in
+ * the current thread, hence this is in a separate proc with arguments
+ * passed explicitly in R1 and R2.
+ */
+stg_killMyself
+{
+ P_ target, exception;
+ target = R1;
+ exception = R2;
+
+ SAVE_THREAD_STATE();
+ /* ToDo: what if the current thread is masking exceptions? */
+ ccall throwToSingleThreaded(MyCapability() "ptr",
+ target "ptr", exception "ptr");
+ 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)) [];
}
}
Catch frames
-------------------------------------------------------------------------- */
-#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
-#else
-#define CATCH_FRAME_BITMAP 1
-#define CATCH_FRAME_WORDS 2
-#endif
-
/* Catch frames are very similar to update frames, but when entering
* one we just pop the frame off the stack and perform the correct
* kind of return to the activation record underneath us on the stack.
*/
-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)))
+#define CATCH_FRAME_FIELDS(w_,p_,info_ptr,p1,p2,exceptions_blocked,handler) \
+ w_ info_ptr, \
+ PROF_HDR_FIELDS(w_,p1,p2) \
+ w_ exceptions_blocked, \
+ p_ handler
+
+
+INFO_TABLE_RET(stg_catch_frame, CATCH_FRAME,
+ CATCH_FRAME_FIELDS(W_,P_,info_ptr, p1, p2,
+ exceptions_blocked,handler))
+ return (P_ ret)
+{
+ unwind Sp = Sp + SIZEOF_StgCatchFrame;
+ return (ret);
+}
/* -----------------------------------------------------------------------------
* The catch infotable
* -------------------------------------------------------------------------- */
INFO_TABLE(stg_catch,2,0,FUN,"catch","catch")
+ (P_ node)
{
- R2 = StgClosure_payload(R1,1); /* h */
- R1 = StgClosure_payload(R1,0); /* x */
- jump catchzh_fast;
+ jump stg_catchzh(StgClosure_payload(node,0),StgClosure_payload(node,1));
}
-catchzh_fast
+stg_catchzh ( P_ io, /* :: IO a */
+ P_ handler /* :: Exception -> IO a */ )
{
- /* args: R1 = m :: IO a, R2 = handler :: Exception -> IO a */
- STK_CHK_GEN(SIZEOF_StgCatchFrame + WDS(1), R1_PTR & R2_PTR, catchzh_fast);
-
- /* Set up the catch frame */
- Sp = Sp - SIZEOF_StgCatchFrame;
- SET_HDR(Sp,stg_catch_frame_info,W_[CCCS]);
-
- StgCatchFrame_handler(Sp) = R2;
- StgCatchFrame_exceptions_blocked(Sp) = TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX;
+ W_ exceptions_blocked;
+
+ STK_CHK_GEN();
+
+ exceptions_blocked =
+ TO_W_(StgTSO_flags(CurrentTSO)) & (TSO_BLOCKEX | TSO_INTERRUPTIBLE);
TICK_CATCHF_PUSHED();
/* Apply R1 to the realworld token */
TICK_UNKNOWN_CALL();
- TICK_SLOW_CALL_v();
- jump stg_ap_v_fast;
+ TICK_SLOW_CALL_fast_v();
+
+ jump stg_ap_v_fast
+ (CATCH_FRAME_FIELDS(,,stg_catch_frame_info, CCCS, 0,
+ exceptions_blocked, handler))
+ (io);
}
/* -----------------------------------------------------------------------------
* The raise infotable
- *
+ *
* This should be exactly the same as would be generated by this STG code
*
* raise = {err} \n {} -> raise#{err}
*
- * It is used in raisezh_fast to update thunks on the update list
+ * It is used in stg_raisezh to update thunks on the update list
* -------------------------------------------------------------------------- */
INFO_TABLE(stg_raise,1,0,THUNK_1_0,"raise","raise")
{
- R1 = StgThunk_payload(R1,0);
- jump raisezh_fast;
+ jump stg_raisezh(StgThunk_payload(R1,0));
+}
+
+section "data" {
+ no_break_on_exception: W_[1];
}
-raisezh_fast
+INFO_TABLE_RET(stg_raise_ret, RET_SMALL, W_ info_ptr, P_ exception)
+ return (P_ ret)
+{
+ unwind Sp = Sp + WDS(2);
+ W_[no_break_on_exception] = 1;
+ jump stg_raisezh (exception);
+}
+
+stg_raisezh /* explicit stack */
+/*
+ * args : R1 :: Exception
+ *
+ * Here we assume that the NativeNodeCall convention always puts the
+ * first argument in R1 (which it does). We cannot use high-level cmm
+ * due to all the LOAD_THREAD_STATE()/SAVE_THREAD_STATE() and stack
+ * walking that happens in here.
+ */
{
W_ handler;
- W_ raise_closure;
W_ frame_type;
- /* args : R1 :: Exception */
+ W_ 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)) {
- foreign "C" fprintCCS_stderr(W_[CCCS] "ptr");
+ if (RtsFlags_ProfFlags_showCCSOnException(RtsFlags) != 0::CBool) {
+ SAVE_THREAD_STATE();
+ ccall fprintCCS_stderr(CCCS "ptr",
+ exception "ptr",
+ CurrentTSO "ptr");
+ LOAD_THREAD_STATE();
}
#endif
retry_pop_stack:
- StgTSO_sp(CurrentTSO) = Sp;
- frame_type = foreign "C" raiseExceptionHelper(BaseReg "ptr", CurrentTSO "ptr", R1 "ptr");
- Sp = StgTSO_sp(CurrentTSO);
+ SAVE_THREAD_STATE();
+ (frame_type) = ccall raiseExceptionHelper(BaseReg "ptr", CurrentTSO "ptr", exception "ptr");
+ LOAD_THREAD_STATE();
if (frame_type == ATOMICALLY_FRAME) {
- /* The exception has reached the edge of a memory transaction. Check that
+ /* 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) = ccall stmValidateNestOfTransactions(MyCapability() "ptr", trec "ptr");
+ outer = StgTRecHeader_enclosing_trec(trec);
+ ccall stmAbortTransaction(MyCapability() "ptr", trec "ptr");
+ ccall stmFreeAbortedTRec(MyCapability() "ptr", trec "ptr");
+
+ if (outer != NO_TREC) {
+ ccall stmAbortTransaction(MyCapability() "ptr", outer "ptr");
+ ccall stmFreeAbortedTRec(MyCapability() "ptr", outer "ptr");
+ }
+
StgTSO_trec(CurrentTSO) = NO_TREC;
- if (r) {
+ if (r != 0) {
// Transaction was valid: continue searching for a catch frame
Sp = Sp + SIZEOF_StgAtomicallyFrame;
goto retry_pop_stack;
} 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) = ccall stmStartTransaction(MyCapability() "ptr", NO_TREC "ptr");
StgTSO_trec(CurrentTSO) = trec;
R1 = StgAtomicallyFrame_code(Sp);
- jump stg_ap_v_fast;
- }
+ jump stg_ap_v_fast [R1];
+ }
+ }
+
+ // 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.
+ CInt[rts_stop_on_exception] = 0;
+ ("ptr" ioAction) = ccall deRefStablePtr (W_[rts_breakpoint_io_action] "ptr");
+ Sp = Sp - WDS(9);
+ Sp(8) = exception;
+ Sp(7) = stg_raise_ret_info;
+ Sp(6) = exception;
+ Sp(5) = ghczmprim_GHCziTypes_True_closure; // True <=> a breakpoint
+ Sp(4) = stg_ap_ppv_info;
+ Sp(3) = 0;
+ Sp(2) = stg_ap_n_info;
+ Sp(1) = 0;
+ R1 = ioAction;
+ jump RET_LBL(stg_ap_n) [R1];
+ }
}
if (frame_type == STOP_FRAME) {
- /*
- * We've stripped the entire stack, the thread is now dead.
- * We will leave the stack in a GC'able state, see the stg_stop_thread
- * entry code in StgStartup.cmm.
- */
- Sp = CurrentTSO + TSO_OFFSET_StgTSO_stack
- + WDS(TO_W_(StgTSO_stack_size(CurrentTSO))) - WDS(2);
- Sp(1) = R1; /* 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;
+ /*
+ * We've stripped the entire stack, the thread is now dead.
+ * We will leave the stack in a GC'able state, see the stg_stop_thread
+ * entry code in StgStartup.cmm.
+ */
+ W_ stack;
+ stack = StgTSO_stackobj(CurrentTSO);
+ Sp = stack + OFFSET_StgStack_stack
+ + WDS(TO_W_(StgStack_stack_size(stack))) - WDS(2);
+ 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! */
+
+ jump stg_threadFinished [];
}
- /* Ok, Sp points to the enclosing CATCH_FRAME or CATCH_STM_FRAME. Pop everything
- * down to and including this frame, update Su, push R1, and enter the handler.
+ /* Ok, Sp points to the enclosing CATCH_FRAME or CATCH_STM_FRAME.
+ * Pop everything down to and including this frame, update Su,
+ * push R1, and enter the handler.
*/
if (frame_type == CATCH_FRAME) {
handler = StgCatchFrame_handler(Sp);
handler = StgCatchSTMFrame_handler(Sp);
}
- /* Restore the blocked/unblocked state for asynchronous exceptions
- * at the CATCH_FRAME.
+ /* Restore the masked/unmasked state for asynchronous exceptions
+ * at the CATCH_FRAME.
*
- * If exceptions were unblocked, arrange that they are unblocked
+ * If exceptions were unmasked, arrange that they are unmasked
* again after executing the handler by pushing an
- * unblockAsyncExceptions_ret stack frame.
+ * unmaskAsyncExceptions_ret stack frame.
+ *
+ * If we've reached an STM catch frame then roll back the nested
+ * transaction we were using.
*/
W_ frame;
frame = Sp;
- if (frame_type == CATCH_FRAME) {
+ if (frame_type == CATCH_FRAME)
+ {
Sp = Sp + SIZEOF_StgCatchFrame;
- if (StgCatchFrame_exceptions_blocked(frame) == 0) {
- Sp_adj(-1);
- Sp(0) = stg_unblockAsyncExceptionszh_ret_info;
+ if ((StgCatchFrame_exceptions_blocked(frame) & TSO_BLOCKEX) == 0) {
+ Sp_adj(-1);
+ Sp(0) = stg_unmaskAsyncExceptionszh_ret_info;
}
- } else {
+
+ /* Ensure that async exceptions are masked when running the handler.
+ */
+ StgTSO_flags(CurrentTSO) = %lobits32(
+ TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX | TSO_INTERRUPTIBLE);
+
+ /* The interruptible state is inherited from the context of the
+ * catch frame, but note that TSO_INTERRUPTIBLE is only meaningful
+ * if TSO_BLOCKEX is set. (we got this wrong earlier, and #4988
+ * was a symptom of the bug).
+ */
+ if ((StgCatchFrame_exceptions_blocked(frame) &
+ (TSO_BLOCKEX | TSO_INTERRUPTIBLE)) == TSO_BLOCKEX) {
+ StgTSO_flags(CurrentTSO) = %lobits32(
+ TO_W_(StgTSO_flags(CurrentTSO)) & ~TSO_INTERRUPTIBLE);
+ }
+ }
+ else /* CATCH_STM_FRAME */
+ {
+ W_ trec, outer;
+ trec = StgTSO_trec(CurrentTSO);
+ outer = StgTRecHeader_enclosing_trec(trec);
+ ccall stmAbortTransaction(MyCapability() "ptr", trec "ptr");
+ ccall stmFreeAbortedTRec(MyCapability() "ptr", trec "ptr");
+ StgTSO_trec(CurrentTSO) = outer;
Sp = Sp + SIZEOF_StgCatchSTMFrame;
}
- /* Ensure that async excpetions are blocked when running the handler.
- */
- StgTSO_flags(CurrentTSO) =
- StgTSO_flags(CurrentTSO) | TSO_BLOCKEX::I32 | TSO_INTERRUPTIBLE::I32;
-
/* Call the handler, passing the exception value and a realworld
* token as arguments.
*/
Sp_adj(-1);
- Sp(0) = R1;
+ Sp(0) = exception;
R1 = handler;
Sp_adj(-1);
TICK_UNKNOWN_CALL();
- TICK_SLOW_CALL_pv();
- jump RET_LBL(stg_ap_pv);
+ TICK_SLOW_CALL_fast_pv();
+ jump RET_LBL(stg_ap_pv) [R1];
}
-raiseIOzh_fast
+stg_raiseIOzh (P_ exception)
{
- /* Args :: R1 :: Exception */
- jump raisezh_fast;
+ jump stg_raisezh (exception);
}
git.haskell.org / ghc.git / blobdiff