--- /dev/null
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The GHC Team, 1998-2004
+ *
+ * Exception support
+ *
+ * This file is written in a subset of C--, extended with various
+ * features specific to GHC. It is compiled by GHC directly. For the
+ * syntax of .cmm files, see the parser in ghc/compiler/cmm/CmmParse.y.
+ *
+ * ---------------------------------------------------------------------------*/
+
+#include "Cmm.h"
+
+/* -----------------------------------------------------------------------------
+ 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
+
+ is used for this purpose. During a blocked section, asynchronous
+ exceptions may be unblocked again temporarily:
+
+ unblockAsyncExceptions# :: IO a -> IO a
+
+ Furthermore, asynchronous exceptions are blocked automatically during
+ the execution of an exception handler. Both of these primitives
+ leave a continuation on the stack which reverts to the previous
+ state (blocked or unblocked) 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
+ the threads waiting to deliver exceptions to that thread.
+
+ -------------------------------------------------------------------------- */
+
+INFO_TABLE_RET( stg_unblockAsyncExceptionszh_ret,
+ 0/*framesize*/, 0/*bitmap*/, RET_SMALL )
+{
+ ASSERT(StgTSO_blocked_exceptions(CurrentTSO) != NULL);
+#if defined(GRAN) || defined(PAR)
+ foreign "C" awakenBlockedQueue(StgTSO_blocked_exceptions(CurrentTSO) "ptr",
+ NULL "ptr");
+#else
+ foreign "C" awakenBlockedQueue(StgTSO_blocked_exceptions(CurrentTSO) "ptr");
+#endif
+ StgTSO_blocked_exceptions(CurrentTSO) = NULL;
+#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 )
+{
+ ASSERT(StgTSO_blocked_exceptions(CurrentTSO) == NULL);
+ StgTSO_blocked_exceptions(CurrentTSO) = END_TSO_QUEUE;
+#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
+{
+ /* Args: R1 :: IO a */
+ STK_CHK_GEN( WDS(2)/* worst case */, R1_PTR, blockAsyncExceptionszh_fast);
+
+ if (StgTSO_blocked_exceptions(CurrentTSO) == NULL) {
+ StgTSO_blocked_exceptions(CurrentTSO) = END_TSO_QUEUE;
+ /* 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;
+ }
+ }
+ Sp_adj(-1);
+ TICK_UNKNOWN_CALL();
+ TICK_SLOW_CALL_v();
+ jump RET_LBL(stg_ap_v);
+}
+
+unblockAsyncExceptionszh_fast
+{
+ /* Args: R1 :: IO a */
+ STK_CHK_GEN( WDS(2), R1_PTR, unblockAsyncExceptionszh_fast);
+
+ if (StgTSO_blocked_exceptions(CurrentTSO) != NULL) {
+#if defined(GRAN) || defined(PAR)
+ foreign "C" awakenBlockedQueue(StgTSO_blocked_exceptions(CurrentTSO) "ptr",
+ StgTSO_block_info(CurrentTSO) "ptr");
+#else
+ foreign "C" awakenBlockedQueue(StgTSO_blocked_exceptions(CurrentTSO) "ptr");
+#endif
+ StgTSO_blocked_exceptions(CurrentTSO) = NULL;
+
+ /* 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;
+ }
+ }
+ Sp_adj(-1);
+ TICK_UNKNOWN_CALL();
+ TICK_SLOW_CALL_v();
+ jump RET_LBL(stg_ap_v);
+}
+
+
+#define interruptible(what_next) \
+ ( what_next == BlockedOnMVar \
+ || what_next == BlockedOnException \
+ || what_next == BlockedOnRead \
+ || what_next == BlockedOnWrite \
+ || what_next == BlockedOnDelay \
+ || what_next == BlockedOnDoProc)
+
+killThreadzh_fast
+{
+ /* args: R1 = TSO to kill, R2 = Exception */
+
+ W_ why_blocked;
+
+ /* This thread may have been relocated.
+ * (see Schedule.c:threadStackOverflow)
+ */
+ while:
+ if (StgTSO_what_next(R1) == ThreadRelocated::I16) {
+ R1 = StgTSO_link(R1);
+ goto while;
+ }
+
+ /* Determine whether this thread is interruptible or not */
+
+ /* If the target thread is currently blocking async exceptions,
+ * we'll have to block until it's ready to accept them. The
+ * exception is interruptible threads - ie. those that are blocked
+ * on some resource.
+ */
+ why_blocked = TO_W_(StgTSO_why_blocked(R1));
+ if (StgTSO_blocked_exceptions(R1) != NULL && !interruptible(why_blocked))
+ {
+ StgTSO_link(CurrentTSO) = StgTSO_blocked_exceptions(R1);
+ StgTSO_blocked_exceptions(R1) = CurrentTSO;
+
+ StgTSO_why_blocked(CurrentTSO) = BlockedOnException::I16;
+ StgTSO_block_info(CurrentTSO) = R1;
+
+ BLOCK( R1_PTR & R2_PTR, killThreadzh_fast );
+ }
+
+ /* Killed threads turn into zombies, which might be garbage
+ * collected at a later date. That's why we don't have to
+ * explicitly remove them from any queues they might be on.
+ */
+
+ /* 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 (R1 == CurrentTSO) {
+ SAVE_THREAD_STATE();
+ foreign "C" raiseAsyncWithLock(R1 "ptr", R2 "ptr");
+ 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));
+ }
+ } else {
+ foreign "C" raiseAsyncWithLock(R1 "ptr", R2 "ptr");
+ }
+
+ 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_adj(1); \
+ Sp = Sp + SIZEOF_StgCatchFrame - WDS(1); \
+ 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)))
+
+/* -----------------------------------------------------------------------------
+ * The catch infotable
+ *
+ * This should be exactly the same as would be generated by this STG code
+ *
+ * catch = {x,h} \n {} -> catch#{x,h}
+ *
+ * It is used in deleteThread when reverting blackholes.
+ * -------------------------------------------------------------------------- */
+
+INFO_TABLE(stg_catch,2,0,FUN,"catch","catch")
+{
+ R2 = StgClosure_payload(R1,1); /* h */
+ R1 = StgClosure_payload(R1,0); /* x */
+ jump catchzh_fast;
+}
+
+catchzh_fast
+{
+ /* 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,CCCS);
+
+ StgCatchFrame_handler(Sp) = R2;
+ StgCatchFrame_exceptions_blocked(Sp) =
+ (StgTSO_blocked_exceptions(CurrentTSO) != NULL);
+ TICK_CATCHF_PUSHED();
+
+ /* Apply R1 to the realworld token */
+ Sp_adj(-1);
+ TICK_UNKNOWN_CALL();
+ TICK_SLOW_CALL_v();
+ jump RET_LBL(stg_ap_v);
+}
+
+/* -----------------------------------------------------------------------------
+ * 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
+ * -------------------------------------------------------------------------- */
+
+INFO_TABLE(stg_raise,1,0,THUNK,"raise","raise")
+{
+ R1 = StgClosure_payload(R1,0);
+ jump raisezh_fast;
+}
+
+raisezh_fast
+{
+ W_ handler;
+ W_ raise_closure;
+ W_ frame_type;
+ /* args : R1 :: Exception */
+
+
+#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,CCCS);
+ }
+#endif
+
+ StgTSO_sp(CurrentTSO) = Sp;
+ frame_type = foreign "C" raiseExceptionHelper(CurrentTSO "ptr", R1 "ptr");
+ Sp = StgTSO_sp(CurrentTSO);
+
+ if (frame_type == STOP_FRAME) {
+ /* We've stripped the entire stack, the thread is now dead. */
+ Sp = CurrentTSO + OFFSET_StgTSO_stack
+ + WDS(StgTSO_stack_size(CurrentTSO)) - WDS(1);
+ Sp(0) = R1; /* save the exception */
+ StgTSO_what_next(CurrentTSO) = ThreadKilled::I16;
+ SAVE_THREAD_STATE(); /* inline! */
+ R1 = ThreadFinished;
+ jump StgReturn;
+ }
+
+ /* Ok, Sp points to the enclosing CATCH_FRAME. Pop everything down to
+ * and including this frame, update Su, push R1, and enter the handler.
+ */
+ handler = StgCatchFrame_handler(Sp);
+
+ /* Restore the blocked/unblocked state for asynchronous exceptions
+ * at the CATCH_FRAME.
+ *
+ * If exceptions were unblocked, arrange that they are unblocked
+ * again after executing the handler by pushing an
+ * unblockAsyncExceptions_ret stack frame.
+ */
+ W_ frame;
+ frame = Sp;
+ Sp = Sp + SIZEOF_StgCatchFrame;
+
+ if (StgCatchFrame_exceptions_blocked(frame) == 0) {
+ Sp_adj(-1);
+ Sp(0) = stg_unblockAsyncExceptionszh_ret_info;
+ }
+
+ /* Ensure that async excpetions are blocked when running the handler.
+ */
+ if (StgTSO_blocked_exceptions(CurrentTSO) == NULL) {
+ StgTSO_blocked_exceptions(CurrentTSO) = END_TSO_QUEUE;
+ }
+
+ /* Call the handler, passing the exception value and a realworld
+ * token as arguments.
+ */
+ Sp_adj(-1);
+ Sp(0) = R1;
+ R1 = handler;
+ Sp_adj(-1);
+ TICK_UNKNOWN_CALL();
+ TICK_SLOW_CALL_pv();
+ jump RET_LBL(stg_ap_pv);
+}
+
+raiseIOzh_fast
+{
+ /* Args :: R1 :: Exception */
+ jump raisezh_fast;
+}
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