#include "Cmm.h"
+#ifdef __PIC__
+import pthread_mutex_unlock;
+#endif
+import EnterCriticalSection;
+import LeaveCriticalSection;
+
/* Stack/Heap Check Failure
* ------------------------
*
- * On discovering that a stack or heap check has failed, we do the following:
+ * Both heap and stack check failures end up in the same place, so
+ * that we can share the code for the failure case when a proc needs
+ * both a stack check and a heap check (a common case).
*
- * - If the context_switch flag is set, indicating that there are more
- * threads waiting to run, we yield to the scheduler
- * (return ThreadYielding).
+ * So when we get here, we have to tell the difference between a stack
+ * check failure and a heap check failure. The code for the checks
+ * looks like this:
+
+ if (Sp - 16 < SpLim) goto c1Tf;
+ Hp = Hp + 16;
+ if (Hp > HpLim) goto c1Th;
+ ...
+ c1Th:
+ HpAlloc = 16;
+ goto c1Tf;
+ c1Tf: jump stg_gc_enter_1 ();
+
+ * Note that Sp is not decremented by the check, whereas Hp is. The
+ * reasons for this seem to be largely historic, I can't think of a
+ * good reason not to decrement Sp at the check too. (--SDM)
*
- * - If Hp > HpLim, we've had a heap check failure. This means we've
- * come to the end of the current heap block, so we try to chain
- * another block on with ExtendNursery().
+ * Note that HpLim may be set to zero arbitrarily by the timer signal
+ * or another processor to trigger a context switch via heap check
+ * failure.
*
- * - If this succeeds, we carry on without returning to the
- * scheduler.
+ * The job of these fragments (stg_gc_enter_1 and friends) is to
+ * 1. Leave no slop in the heap, so Hp must be retreated if it was
+ * incremented by the check. No-slop is a requirement for LDV
+ * profiling, at least.
+ * 2. If a heap check failed, try to grab another heap block from
+ * the nursery and continue.
+ * 3. otherwise, return to the scheduler with StackOverflow,
+ * HeapOverflow, or ThreadYielding as appropriate.
*
- * - If it fails, we return to the scheduler claiming HeapOverflow
- * so that a garbage collection can be performed.
+ * We can tell whether Hp was incremented, because HpAlloc is
+ * non-zero: HpAlloc is required to be zero at all times unless a
+ * heap-check just failed, which is why the stack-check failure case
+ * does not set HpAlloc (see code fragment above). So that covers (1).
+ * HpAlloc is zeroed in LOAD_THREAD_STATE().
*
- * - If Hp <= HpLim, it must have been a stack check that failed. In
- * which case, we return to the scheduler claiming StackOverflow, the
- * scheduler will either increase the size of our stack, or raise
- * an exception if the stack is already too big.
+ * If Hp > HpLim, then either (a) we have reached the end of the
+ * current heap block, or (b) HpLim == 0 and we should yield. Hence
+ * check Hp > HpLim first, and then HpLim == 0 to decide whether to
+ * return ThreadYielding or try to grab another heap block from the
+ * nursery.
*
- * The effect of checking for context switch only in the heap/stack check
- * failure code is that we'll switch threads after the current thread has
- * reached the end of its heap block. If a thread isn't allocating
- * at all, it won't yield. Hopefully this won't be a problem in practice.
+ * If Hp <= HpLim, then this must be a StackOverflow. The scheduler
+ * will either increase the size of our stack, or raise an exception if
+ * the stack is already too big.
*/
#define PRE_RETURN(why,what_next) \
* ThreadRunGHC thread.
*/
-#define GC_GENERIC \
- DEBUG_ONLY(foreign "C" heapCheckFail()); \
- if (Hp > HpLim) { \
- Hp = Hp - HpAlloc/*in bytes*/; \
- if (HpAlloc <= BLOCK_SIZE \
- && bdescr_link(CurrentNursery) != NULL) { \
- CLOSE_NURSERY(); \
- CurrentNursery = bdescr_link(CurrentNursery); \
- OPEN_NURSERY(); \
- if (CInt[context_switch] != 0 :: CInt) { \
- R1 = ThreadYielding; \
- goto sched; \
- } else { \
- jump %ENTRY_CODE(Sp(0)); \
- } \
- } else { \
- R1 = HeapOverflow; \
- goto sched; \
- } \
- } else { \
- R1 = StackOverflow; \
- } \
- sched: \
- PRE_RETURN(R1,ThreadRunGHC); \
+#define GC_GENERIC \
+ DEBUG_ONLY(foreign "C" heapCheckFail()); \
+ if (Hp > HpLim) { \
+ Hp = Hp - HpAlloc/*in bytes*/; \
+ if (HpLim == 0) { \
+ R1 = ThreadYielding; \
+ goto sched; \
+ } \
+ if (HpAlloc <= BLOCK_SIZE \
+ && bdescr_link(CurrentNursery) != NULL) { \
+ HpAlloc = 0; \
+ CLOSE_NURSERY(); \
+ CurrentNursery = bdescr_link(CurrentNursery); \
+ OPEN_NURSERY(); \
+ if (Capability_context_switch(MyCapability()) != 0 :: CInt) { \
+ R1 = ThreadYielding; \
+ goto sched; \
+ } else { \
+ jump %ENTRY_CODE(Sp(0)); \
+ } \
+ } else { \
+ R1 = HeapOverflow; \
+ goto sched; \
+ } \
+ } else { \
+ R1 = StackOverflow; \
+ } \
+ sched: \
+ PRE_RETURN(R1,ThreadRunGHC); \
jump stg_returnToSched;
#define HP_GENERIC \
There are canned sequences for 'n' pointer values in registers.
-------------------------------------------------------------------------- */
-INFO_TABLE_RET( stg_enter, RET_SMALL, "ptr" W_ unused)
+INFO_TABLE_RET( stg_enter, RET_SMALL, P_ unused)
{
R1 = Sp(1);
Sp_adj(2);
GC_GENERIC
}
-#if defined(GRAN)
-/*
- ToDo: merge the block and yield macros, calling something like BLOCK(N)
- at the end;
-*/
-
-/*
- Should we actually ever do a yield in such a case?? -- HWL
-*/
-gran_yield_0
-{
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-gran_yield_1
-{
- Sp_adj(-1);
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-/*- 2 Regs--------------------------------------------------------------------*/
-
-gran_yield_2
-{
- Sp_adj(-2);
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-/*- 3 Regs -------------------------------------------------------------------*/
-
-gran_yield_3
-{
- Sp_adj(-3);
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-/*- 4 Regs -------------------------------------------------------------------*/
-
-gran_yield_4
-{
- Sp_adj(-4);
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-/*- 5 Regs -------------------------------------------------------------------*/
-
-gran_yield_5
-{
- Sp_adj(-5);
- Sp(4) = R5;
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-/*- 6 Regs -------------------------------------------------------------------*/
-
-gran_yield_6
-{
- Sp_adj(-6);
- Sp(5) = R6;
- Sp(4) = R5;
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-/*- 7 Regs -------------------------------------------------------------------*/
-
-gran_yield_7
-{
- Sp_adj(-7);
- Sp(6) = R7;
- Sp(5) = R6;
- Sp(4) = R5;
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-/*- 8 Regs -------------------------------------------------------------------*/
-
-gran_yield_8
-{
- Sp_adj(-8);
- Sp(7) = R8;
- Sp(6) = R7;
- Sp(5) = R6;
- Sp(4) = R5;
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadYielding;
- jump StgReturn;
-}
-
-// the same routines but with a block rather than a yield
-
-gran_block_1
-{
- Sp_adj(-1);
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
-}
-
-/*- 2 Regs--------------------------------------------------------------------*/
-
-gran_block_2
-{
- Sp_adj(-2);
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
-}
-
-/*- 3 Regs -------------------------------------------------------------------*/
-
-gran_block_3
-{
- Sp_adj(-3);
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
-}
-
-/*- 4 Regs -------------------------------------------------------------------*/
-
-gran_block_4
-{
- Sp_adj(-4);
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
-}
-
-/*- 5 Regs -------------------------------------------------------------------*/
-
-gran_block_5
-{
- Sp_adj(-5);
- Sp(4) = R5;
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
-}
-
-/*- 6 Regs -------------------------------------------------------------------*/
-
-gran_block_6
-{
- Sp_adj(-6);
- Sp(5) = R6;
- Sp(4) = R5;
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
-}
-
-/*- 7 Regs -------------------------------------------------------------------*/
-
-gran_block_7
-{
- Sp_adj(-7);
- Sp(6) = R7;
- Sp(5) = R6;
- Sp(4) = R5;
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
-}
-
-/*- 8 Regs -------------------------------------------------------------------*/
-
-gran_block_8
-{
- Sp_adj(-8);
- Sp(7) = R8;
- Sp(6) = R7;
- Sp(5) = R6;
- Sp(4) = R5;
- Sp(3) = R4;
- Sp(2) = R3;
- Sp(1) = R2;
- Sp(0) = R1;
- SAVE_THREAD_STATE();
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
-}
-
-#endif
-
-#if 0 && defined(PAR)
-
-/*
- Similar to stg_block_1 (called via StgMacro BLOCK_NP) but separates the
- saving of the thread state from the actual jump via an StgReturn.
- We need this separation because we call RTS routines in blocking entry codes
- before jumping back into the RTS (see parallel/FetchMe.hc).
-*/
-
-par_block_1_no_jump
-{
- Sp_adj(-1);
- Sp(0) = R1;
- SAVE_THREAD_STATE();
-}
+/* -----------------------------------------------------------------------------
+ stg_enter_checkbh is just like stg_enter, except that we also call
+ checkBlockingQueues(). The point of this is that the GC can
+ replace an stg_marked_upd_frame with an stg_enter_checkbh if it
+ finds that the BLACKHOLE has already been updated by another
+ thread. It would be unsafe to use stg_enter, because there might
+ be an orphaned BLOCKING_QUEUE now.
+ -------------------------------------------------------------------------- */
-par_jump
+INFO_TABLE_RET( stg_enter_checkbh, RET_SMALL, P_ unused)
{
- TSO_what_next(CurrentTSO) = ThreadRunGHC;
- R1 = ThreadBlocked;
- jump StgReturn;
+ R1 = Sp(1);
+ Sp_adj(2);
+ foreign "C" checkBlockingQueues(MyCapability() "ptr",
+ CurrentTSO) [R1];
+ ENTER();
}
-#endif
-
/* -----------------------------------------------------------------------------
Heap checks in Primitive case alternatives
/*-- R1 is boxed/unpointed -------------------------------------------------- */
-INFO_TABLE_RET( stg_gc_unpt_r1, RET_SMALL, "ptr" W_ unused)
+INFO_TABLE_RET( stg_gc_unpt_r1, RET_SMALL, P_ unused)
{
R1 = Sp(1);
Sp_adj(2);
/*-- Unboxed tuple return, one pointer (unregisterised build only) ---------- */
-INFO_TABLE_RET( stg_ut_1_0_unreg, RET_SMALL, "ptr" W_ unused )
+INFO_TABLE_RET( stg_ut_1_0_unreg, RET_SMALL, P_ unused )
{
Sp_adj(1);
// one ptr is on the stack (Sp(0))
W_ info;
W_ type;
- info = %GET_FUN_INFO(R1);
+ info = %GET_FUN_INFO(UNTAG(R1));
// cache the size
type = TO_W_(StgFunInfoExtra_fun_type(info));
#ifdef TABLES_NEXT_TO_CODE
// bitmap field holds an offset
size = StgLargeBitmap_size( StgFunInfoExtra_bitmap(info)
- + %GET_ENTRY(R1) /* ### */ );
+ + %GET_ENTRY(UNTAG(R1)) /* ### */ );
#else
size = StgLargeBitmap_size( StgFunInfoExtra_bitmap(info) );
#endif
#ifdef NO_ARG_REGS
// Minor optimisation: there are no argument registers to load up,
// so we can just jump straight to the function's entry point.
- jump %GET_ENTRY(R1);
+ jump %GET_ENTRY(UNTAG(R1));
#else
W_ info;
W_ type;
- info = %GET_FUN_INFO(R1);
+ info = %GET_FUN_INFO(UNTAG(R1));
type = TO_W_(StgFunInfoExtra_fun_type(info));
if (type == ARG_GEN || type == ARG_GEN_BIG) {
jump StgFunInfoExtra_slow_apply(info);
stg_gc_gen
{
+ // Hack; see Note [mvar-heap-check] in PrimOps.cmm
+ if (R10 == stg_putMVarzh || R10 == stg_takeMVarzh) {
+ unlockClosure(R1, stg_MVAR_DIRTY_info)
+ }
SAVE_EVERYTHING;
GC_GENERIC
-}
+}
// A heap check at an unboxed tuple return point. The return address
// is on the stack, and we can find it by using the offsets given
*
* -------------------------------------------------------------------------- */
-INFO_TABLE_RET( stg_block_takemvar, RET_SMALL, "ptr" W_ unused )
+INFO_TABLE_RET( stg_block_takemvar, RET_SMALL, P_ unused )
{
R1 = Sp(1);
Sp_adj(2);
- jump takeMVarzh_fast;
+ jump stg_takeMVarzh;
}
// code fragment executed just before we return to the scheduler
stg_block_takemvar_finally
{
-#ifdef THREADED_RTS
- unlockClosure(R3, stg_EMPTY_MVAR_info);
-#endif
+ unlockClosure(R3, stg_MVAR_DIRTY_info);
jump StgReturn;
}
BLOCK_BUT_FIRST(stg_block_takemvar_finally);
}
-INFO_TABLE_RET( stg_block_putmvar, RET_SMALL, "ptr" W_ unused1, "ptr" W_ unused2 )
+INFO_TABLE_RET( stg_block_putmvar, RET_SMALL, P_ unused1, P_ unused2 )
{
R2 = Sp(2);
R1 = Sp(1);
Sp_adj(3);
- jump putMVarzh_fast;
+ jump stg_putMVarzh;
}
// code fragment executed just before we return to the scheduler
stg_block_putmvar_finally
{
-#ifdef THREADED_RTS
- unlockClosure(R3, stg_FULL_MVAR_info);
-#endif
+ unlockClosure(R3, stg_MVAR_DIRTY_info);
jump StgReturn;
}
BLOCK_BUT_FIRST(stg_block_putmvar_finally);
}
-// code fragment executed just before we return to the scheduler
-stg_block_blackhole_finally
-{
-#if defined(THREADED_RTS)
- // The last thing we do is release sched_lock, which is
- // preventing other threads from accessing blackhole_queue and
- // picking up this thread before we are finished with it.
- foreign "C" RELEASE_LOCK(sched_mutex "ptr");
-#endif
- jump StgReturn;
-}
-
stg_block_blackhole
{
Sp_adj(-2);
Sp(1) = R1;
Sp(0) = stg_enter_info;
- BLOCK_BUT_FIRST(stg_block_blackhole_finally);
+ BLOCK_GENERIC;
}
-INFO_TABLE_RET( stg_block_throwto, RET_SMALL, "ptr" W_ unused, "ptr" W_ unused )
+INFO_TABLE_RET( stg_block_throwto, RET_SMALL, P_ unused, P_ unused )
{
R2 = Sp(2);
R1 = Sp(1);
Sp_adj(3);
- jump killThreadzh_fast;
+ jump stg_killThreadzh;
}
stg_block_throwto_finally
{
-#ifdef THREADED_RTS
- foreign "C" throwToReleaseTarget (R3 "ptr");
-#endif
+ // unlock the throwto message, but only if it wasn't already
+ // unlocked. It may have been unlocked if we revoked the message
+ // due to an exception being raised during threadPaused().
+ if (StgHeader_info(StgTSO_block_info(CurrentTSO)) == stg_WHITEHOLE_info) {
+ unlockClosure(StgTSO_block_info(CurrentTSO), stg_MSG_THROWTO_info);
+ }
jump StgReturn;
}
}
#ifdef mingw32_HOST_OS
-INFO_TABLE_RET( stg_block_async, RET_SMALL )
+INFO_TABLE_RET( stg_block_async, RET_SMALL, W_ unused )
{
W_ ares;
W_ len, errC;
- ares = StgTSO_block_info(CurrentTSO);
+ ares = Sp(1);
len = StgAsyncIOResult_len(ares);
errC = StgAsyncIOResult_errCode(ares);
- StgTSO_block_info(CurrentTSO) = NULL;
foreign "C" free(ares "ptr");
R1 = len;
+ Sp_adj(1);
Sp(0) = errC;
jump %ENTRY_CODE(Sp(1));
}
stg_block_async
{
- Sp_adj(-1);
+ Sp_adj(-2);
Sp(0) = stg_block_async_info;
BLOCK_GENERIC;
}
/* Used by threadDelay implementation; it would be desirable to get rid of
* this free()'ing void return continuation.
*/
-INFO_TABLE_RET( stg_block_async_void, RET_SMALL )
+INFO_TABLE_RET( stg_block_async_void, RET_SMALL, W_ ares )
{
W_ ares;
- ares = StgTSO_block_info(CurrentTSO);
- StgTSO_block_info(CurrentTSO) = NULL;
+ ares = Sp(1);
foreign "C" free(ares "ptr");
- Sp_adj(1);
+ Sp_adj(2);
jump %ENTRY_CODE(Sp(0));
}
stg_block_async_void
{
- Sp_adj(-1);
+ Sp_adj(-2);
Sp(0) = stg_block_async_void_info;
BLOCK_GENERIC;
}
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