X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=rts%2FException.cmm;h=55c79cede7890d08b5d41d17e3a00eebf95a7c9e;hp=ae123f9421d9aa7f47d8dfea30e09fc304c3be55;hb=7408b39235bccdcde48df2a73337ff976fbc09b7;hpb=80578b7defea703ad24efa908534a13e2ebc880b diff --git a/rts/Exception.cmm b/rts/Exception.cmm index ae123f9..55c79ce 100644 --- a/rts/Exception.cmm +++ b/rts/Exception.cmm @@ -13,6 +13,8 @@ #include "Cmm.h" #include "RaiseAsync.h" +import ghczmprim_GHCziBool_True_closure; + /* ----------------------------------------------------------------------------- Exception Primitives @@ -43,63 +45,76 @@ 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); +STRING(stg_unblockAsync_err_str, "unblockAsyncExceptions#_ret") - foreign "C" awakenBlockedExceptionQueue(MyCapability() "ptr", - CurrentTSO "ptr") [R1]; +INFO_TABLE_RET( stg_unblockAsyncExceptionszh_ret, RET_SMALL ) +{ + CInt r; StgTSO_flags(CurrentTSO) = StgTSO_flags(CurrentTSO) & - ~(TSO_BLOCKEX::I32|TSO_INTERRUPTIBLE::I32); + %lobits32(~(TSO_BLOCKEX|TSO_INTERRUPTIBLE)); + + /* 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. + */ + + STK_CHK_GEN( WDS(2), R1_PTR, stg_unblockAsyncExceptionszh_ret_info); + Sp_adj(-2); + Sp(1) = R1; + Sp(0) = stg_gc_unpt_r1_info; + 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)); + } + } + 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); + } + } -#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_blockAsyncExceptionszh_ret, - 0/*framesize*/, 0/*bitmap*/, RET_SMALL ) +INFO_TABLE_RET( stg_blockAsyncExceptionszh_ret, 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; + StgTSO_flags(CurrentTSO) = %lobits32( + TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX | TSO_INTERRUPTIBLE); -#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 } -blockAsyncExceptionszh_fast +stg_blockAsyncExceptionszh { /* Args: R1 :: IO a */ - STK_CHK_GEN( WDS(2)/* worst case */, R1_PTR, blockAsyncExceptionszh_fast); + STK_CHK_GEN( WDS(2)/* worst case */, R1_PTR, stg_blockAsyncExceptionszh); if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) == 0) { - StgTSO_flags(CurrentTSO) = - StgTSO_flags(CurrentTSO) | TSO_BLOCKEX::I32 | TSO_INTERRUPTIBLE::I32; + StgTSO_flags(CurrentTSO) = %lobits32( + TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX | TSO_INTERRUPTIBLE); /* avoid growing the stack unnecessarily */ if (Sp(0) == stg_blockAsyncExceptionszh_ret_info) { @@ -114,17 +129,21 @@ blockAsyncExceptionszh_fast jump stg_ap_v_fast; } -unblockAsyncExceptionszh_fast +stg_unblockAsyncExceptionszh { + CInt r; + /* Args: R1 :: IO a */ - STK_CHK_GEN( WDS(2), R1_PTR, unblockAsyncExceptionszh_fast); + STK_CHK_GEN( WDS(4), R1_PTR, stg_unblockAsyncExceptionszh); + /* 4 words: one for the unblock frame, 3 for setting up the + * stack to call maybePerformBlockedException() below. + */ + /* If exceptions are already unblocked, there's nothing to do */ 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); + StgTSO_flags(CurrentTSO) = %lobits32( + TO_W_(StgTSO_flags(CurrentTSO)) & ~(TSO_BLOCKEX|TSO_INTERRUPTIBLE)); /* avoid growing the stack unnecessarily */ if (Sp(0) == stg_unblockAsyncExceptionszh_ret_info) { @@ -133,14 +152,60 @@ unblockAsyncExceptionszh_fast Sp_adj(-1); Sp(0) = stg_blockAsyncExceptionszh_ret_info; } + + /* 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. + * + * 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) = R1; + Sp(0) = stg_enter_info; + + 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)); + } + } else { + /* we'll just call R1 directly, below */ + Sp_adj(3); + } + } + } TICK_UNKNOWN_CALL(); TICK_SLOW_CALL_v(); jump stg_ap_v_fast; } +stg_asyncExceptionsBlockedzh +{ + /* args: none */ + if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) != 0) { + RET_N(1); + } else { + RET_N(0); + } +} -killThreadzh_fast +stg_killThreadzh { /* args: R1 = TSO to kill, R2 = Exception */ @@ -151,7 +216,8 @@ killThreadzh_fast 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_GEN( WDS(3), R1_PTR & R2_PTR, stg_killThreadzh); /* * We might have killed ourselves. In which case, better be *very* @@ -159,14 +225,26 @@ killThreadzh_fast * If the exception went to a catch frame, we'll just continue from * the handler. */ + loop: + if (StgTSO_what_next(target) == ThreadRelocated::I16) { + target = StgTSO__link(target); + goto loop; + } if (target == CurrentTSO) { + /* + * 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. + */ 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; + jump stg_threadFinished; } else { LOAD_THREAD_STATE(); ASSERT(StgTSO_what_next(CurrentTSO) == ThreadRunGHC::I16); @@ -174,27 +252,22 @@ killThreadzh_fast } } 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) { + W_ msg; + out = Sp - WDS(1); /* ok to re-use stack space here */ - case THROWTO_SUCCESS: { + (msg) = foreign "C" throwTo(MyCapability() "ptr", + CurrentTSO "ptr", + target "ptr", + exception "ptr") [R1,R2]; + + if (msg == NULL) { jump %ENTRY_CODE(Sp(0)); - } - - case THROWTO_BLOCKED: { - R3 = W_[out]; - // we must block, and call throwToReleaseTarget() before returning + } else { + StgTSO_why_blocked(CurrentTSO) = BlockedOnMsgThrowTo; + StgTSO_block_info(CurrentTSO) = msg; + // we must block, and unlock the message before returning jump stg_block_throwto; } - } } } @@ -202,69 +275,22 @@ killThreadzh_fast 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))) +INFO_TABLE_RET(stg_catch_frame, CATCH_FRAME, +#if defined(PROFILING) + W_ unused1, W_ unused2, +#endif + W_ unused3, P_ unused4) + { + Sp = Sp + SIZEOF_StgCatchFrame; + jump %ENTRY_CODE(Sp(SP_OFF)); + } /* ----------------------------------------------------------------------------- * The catch infotable @@ -280,13 +306,13 @@ INFO_TABLE(stg_catch,2,0,FUN,"catch","catch") { R2 = StgClosure_payload(R1,1); /* h */ R1 = StgClosure_payload(R1,0); /* x */ - jump catchzh_fast; + jump stg_catchzh; } -catchzh_fast +stg_catchzh { /* args: R1 = m :: IO a, R2 = handler :: Exception -> IO a */ - STK_CHK_GEN(SIZEOF_StgCatchFrame + WDS(1), R1_PTR & R2_PTR, catchzh_fast); + STK_CHK_GEN(SIZEOF_StgCatchFrame + WDS(1), R1_PTR & R2_PTR, stg_catchzh); /* Set up the catch frame */ Sp = Sp - SIZEOF_StgCatchFrame; @@ -309,22 +335,35 @@ catchzh_fast * * 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; } -raisezh_fast +section "data" { + no_break_on_exception: W_[1]; +} + +INFO_TABLE_RET(stg_raise_ret, RET_SMALL, P_ arg1) +{ + R1 = Sp(1); + Sp = Sp + WDS(2); + W_[no_break_on_exception] = 1; + jump stg_raisezh; +} + +stg_raisezh { 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. */ @@ -333,16 +372,13 @@ raisezh_fast * the info was only displayed for an *uncaught* exception. */ if (RtsFlags_ProfFlags_showCCSOnException(RtsFlags) != 0::I32) { - foreign "C" fprintCCS_stderr(W_[CCCS] "ptr"); + foreign "C" fprintCCS_stderr(W_[CCCS] "ptr") []; } #endif - /* Inform the Hpc that an exception has been thrown */ - foreign "C" hs_hpc_event("Raise",CurrentTSO); - 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 @@ -356,14 +392,14 @@ retry_pop_stack: W_ trec, outer; W_ r; trec = StgTSO_trec(CurrentTSO); - 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"); + (r) = foreign "C" stmValidateNestOfTransactions(trec "ptr") []; + outer = StgTRecHeader_enclosing_trec(trec); + 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"); + foreign "C" stmAbortTransaction(MyCapability() "ptr", outer "ptr") []; + foreign "C" stmFreeAbortedTRec(MyCapability() "ptr", outer "ptr") []; } StgTSO_trec(CurrentTSO) = NO_TREC; @@ -374,13 +410,43 @@ 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) = 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. + CInt[rts_stop_on_exception] = 0; + ("ptr" ioAction) = foreign "C" deRefStablePtr (W_[rts_breakpoint_io_action] "ptr") []; + Sp = Sp - WDS(7); + Sp(6) = exception; + Sp(5) = stg_raise_ret_info; + Sp(4) = stg_noforceIO_info; // required for unregisterised + Sp(3) = exception; // the AP_STACK + Sp(2) = ghczmprim_GHCziBool_True_closure; // dummy breakpoint info + Sp(1) = ghczmprim_GHCziBool_True_closure; // True <=> a breakpoint + R1 = ioAction; + jump RET_LBL(stg_ap_pppv); + } + } + if (frame_type == STOP_FRAME) { /* * We've stripped the entire stack, the thread is now dead. @@ -389,16 +455,12 @@ retry_pop_stack: */ 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 @@ -431,7 +493,7 @@ retry_pop_stack: } else { W_ trec, outer; trec = StgTSO_trec(CurrentTSO); - "ptr" outer = foreign "C" stmGetEnclosingTRec(trec "ptr") []; + outer = StgTRecHeader_enclosing_trec(trec); foreign "C" stmAbortTransaction(MyCapability() "ptr", trec "ptr") []; foreign "C" stmFreeAbortedTRec(MyCapability() "ptr", trec "ptr") []; StgTSO_trec(CurrentTSO) = outer; @@ -440,14 +502,14 @@ retry_pop_stack: /* Ensure that async excpetions are blocked when running the handler. */ - StgTSO_flags(CurrentTSO) = - StgTSO_flags(CurrentTSO) | TSO_BLOCKEX::I32 | TSO_INTERRUPTIBLE::I32; + StgTSO_flags(CurrentTSO) = %lobits32( + TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX | TSO_INTERRUPTIBLE); /* 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(); @@ -455,8 +517,8 @@ retry_pop_stack: jump RET_LBL(stg_ap_pv); } -raiseIOzh_fast +stg_raiseIOzh { /* Args :: R1 :: Exception */ - jump raisezh_fast; + jump stg_raisezh; }