diff options
Diffstat (limited to 'rts/Exception.cmm')
| -rw-r--r-- | rts/Exception.cmm | 156 |
1 files changed, 111 insertions, 45 deletions
diff --git a/rts/Exception.cmm b/rts/Exception.cmm index af846928b5..7d1bf3979a 100644 --- a/rts/Exception.cmm +++ b/rts/Exception.cmm @@ -21,12 +21,12 @@ import ghczmprim_GHCziBool_True_closure; 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 + maskAsyncExceptions# :: IO a -> IO a is used for this purpose. During a blocked section, asynchronous exceptions may be unblocked again temporarily: - unblockAsyncExceptions# :: IO a -> IO a + unmaskAsyncExceptions# :: IO a -> IO a Furthermore, asynchronous exceptions are blocked automatically during the execution of an exception handler. Both of these primitives @@ -39,34 +39,33 @@ import ghczmprim_GHCziBool_True_closure; 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 + containing the unmaskAsyncExceptions_ret frame. Later, when someone else evaluates this thunk, the blocked exception state is not restored. -------------------------------------------------------------------------- */ -STRING(stg_unblockAsync_err_str, "unblockAsyncExceptions#_ret") -INFO_TABLE_RET( stg_unblockAsyncExceptionszh_ret, RET_SMALL ) +INFO_TABLE_RET(stg_unmaskAsyncExceptionszh_ret, RET_SMALL) { CInt r; - StgTSO_flags(CurrentTSO) = StgTSO_flags(CurrentTSO) & - %lobits32(~(TSO_BLOCKEX|TSO_INTERRUPTIBLE)); + StgTSO_flags(CurrentTSO) = %lobits32( + TO_W_(StgTSO_flags(CurrentTSO)) & ~(TSO_BLOCKEX|TSO_INTERRUPTIBLE)); /* Eagerly raise a blocked exception, if there is one */ if (StgTSO_blocked_exceptions(CurrentTSO) != END_TSO_QUEUE) { + + STK_CHK_GEN( WDS(2), R1_PTR, stg_unmaskAsyncExceptionszh_ret_info); /* * 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; @@ -97,44 +96,94 @@ INFO_TABLE_RET( stg_unblockAsyncExceptionszh_ret, RET_SMALL ) jump %ENTRY_CODE(Sp(0)); } -INFO_TABLE_RET( stg_blockAsyncExceptionszh_ret, RET_SMALL ) +INFO_TABLE_RET(stg_maskAsyncExceptionszh_ret, RET_SMALL) { - StgTSO_flags(CurrentTSO) = %lobits32( - TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX | TSO_INTERRUPTIBLE); + StgTSO_flags(CurrentTSO) = + %lobits32( + TO_W_(StgTSO_flags(CurrentTSO)) + | TSO_BLOCKEX | TSO_INTERRUPTIBLE + ); Sp_adj(1); jump %ENTRY_CODE(Sp(0)); } -stg_blockAsyncExceptionszh +INFO_TABLE_RET(stg_maskUninterruptiblezh_ret, RET_SMALL) +{ + StgTSO_flags(CurrentTSO) = + %lobits32( + (TO_W_(StgTSO_flags(CurrentTSO)) + | TSO_BLOCKEX) + & ~TSO_INTERRUPTIBLE + ); + + Sp_adj(1); + jump %ENTRY_CODE(Sp(0)); +} + +stg_maskAsyncExceptionszh { /* Args: R1 :: IO a */ - STK_CHK_GEN( WDS(2)/* worst case */, R1_PTR, stg_blockAsyncExceptionszh); + STK_CHK_GEN( WDS(1)/* worst case */, R1_PTR, stg_maskAsyncExceptionszh); if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) == 0) { - - StgTSO_flags(CurrentTSO) = %lobits32( - TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX | TSO_INTERRUPTIBLE); + /* 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; + } + } - /* 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; - } + 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; +} + +stg_maskUninterruptiblezh +{ + /* Args: R1 :: IO a */ + STK_CHK_GEN( WDS(1)/* worst case */, R1_PTR, stg_maskAsyncExceptionszh); + + if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) == 0) { + /* 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; } -stg_unblockAsyncExceptionszh +stg_unmaskAsyncExceptionszh { CInt r; + W_ level; /* Args: R1 :: IO a */ - STK_CHK_GEN( WDS(4), R1_PTR, stg_unblockAsyncExceptionszh); + STK_CHK_GEN( WDS(4), R1_PTR, stg_unmaskAsyncExceptionszh); /* 4 words: one for the unblock frame, 3 for setting up the * stack to call maybePerformBlockedException() below. */ @@ -142,17 +191,21 @@ stg_unblockAsyncExceptionszh /* If exceptions are already unblocked, there's nothing to do */ if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) != 0) { - 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) { + if (Sp(0) == stg_unmaskAsyncExceptionszh_ret_info) { Sp_adj(1); } else { Sp_adj(-1); - Sp(0) = stg_blockAsyncExceptionszh_ret_info; + 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 blocked exception, if there is one */ if (StgTSO_blocked_exceptions(CurrentTSO) != END_TSO_QUEUE) { /* @@ -195,14 +248,17 @@ stg_unblockAsyncExceptionszh jump stg_ap_v_fast; } -stg_asyncExceptionsBlockedzh + +stg_getMaskingStatezh { /* args: none */ - if ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) != 0) { - RET_N(1); - } else { - RET_N(0); - } + /* + returns: 0 == unmasked, + 1 == masked, non-interruptible, + 2 == masked, interruptible + */ + RET_N(((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX) != 0) + + ((TO_W_(StgTSO_flags(CurrentTSO)) & TSO_INTERRUPTIBLE) != 0)); } stg_killThreadzh @@ -321,7 +377,8 @@ stg_catchzh SET_HDR(Sp,stg_catch_frame_info,W_[CCCS]); StgCatchFrame_handler(Sp) = R2; - StgCatchFrame_exceptions_blocked(Sp) = TO_W_(StgTSO_flags(CurrentTSO)) & TSO_BLOCKEX; + StgCatchFrame_exceptions_blocked(Sp) = + TO_W_(StgTSO_flags(CurrentTSO)) & (TSO_BLOCKEX | TSO_INTERRUPTIBLE); TICK_CATCHF_PUSHED(); /* Apply R1 to the realworld token */ @@ -479,7 +536,7 @@ retry_pop_stack: * * If exceptions were unblocked, arrange that they are unblocked * 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. @@ -488,9 +545,9 @@ retry_pop_stack: frame = Sp; 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 { W_ trec, outer; @@ -503,9 +560,18 @@ retry_pop_stack: } /* Ensure that async excpetions are blocked when running the handler. + * The interruptible state is inherited from the context of the + * catch frame. */ StgTSO_flags(CurrentTSO) = %lobits32( - TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX | TSO_INTERRUPTIBLE); + TO_W_(StgTSO_flags(CurrentTSO)) | TSO_BLOCKEX); + if ((StgCatchFrame_exceptions_blocked(frame) & TSO_INTERRUPTIBLE) == 0) { + StgTSO_flags(CurrentTSO) = %lobits32( + TO_W_(StgTSO_flags(CurrentTSO)) & ~TSO_INTERRUPTIBLE); + } else { + StgTSO_flags(CurrentTSO) = %lobits32( + TO_W_(StgTSO_flags(CurrentTSO)) | TSO_INTERRUPTIBLE); + } /* Call the handler, passing the exception value and a realworld * token as arguments. |