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PrimOps.cmm
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PrimOps.cmm
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/* -*- tab-width: 8 -*- */
/* -----------------------------------------------------------------------------
*
* (c) The GHC Team, 1998-2012
*
* Out-of-line primitive operations
*
* This file contains the implementations of all the primitive
* operations ("primops") which are not expanded inline. See
* ghc/compiler/prelude/primops.txt.pp for a list of all the primops;
* this file contains code for most of those with the attribute
* out_of_line=True.
*
* Entry convention: the entry convention for a primop is the
* NativeNodeCall convention, and the return convention is
* NativeReturn. (see compiler/cmm/CmmCallConv.hs)
*
* 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"
#ifdef __PIC__
import pthread_mutex_lock;
import pthread_mutex_unlock;
#endif
import base_ControlziExceptionziBase_nestedAtomically_closure;
import EnterCriticalSection;
import LeaveCriticalSection;
import ghczmprim_GHCziTypes_False_closure;
#if defined(USE_MINIINTERPRETER) || !defined(mingw32_HOST_OS)
import sm_mutex;
#endif
/*-----------------------------------------------------------------------------
Array Primitives
Basically just new*Array - the others are all inline macros.
The slow entry point is for returning from a heap check, the saved
size argument must be re-loaded from the stack.
-------------------------------------------------------------------------- */
/* for objects that are *less* than the size of a word, make sure we
* round up to the nearest word for the size of the array.
*/
stg_newByteArrayzh ( W_ n )
{
W_ words, payload_words;
gcptr p;
MAYBE_GC_N(stg_newByteArrayzh, n);
payload_words = ROUNDUP_BYTES_TO_WDS(n);
words = BYTES_TO_WDS(SIZEOF_StgArrWords) + payload_words;
("ptr" p) = ccall allocate(MyCapability() "ptr",words);
TICK_ALLOC_PRIM(SIZEOF_StgArrWords,WDS(payload_words),0);
SET_HDR(p, stg_ARR_WORDS_info, CCCS);
StgArrWords_bytes(p) = n;
return (p);
}
#define BA_ALIGN 16
#define BA_MASK (BA_ALIGN-1)
stg_newPinnedByteArrayzh ( W_ n )
{
W_ words, bytes, payload_words;
gcptr p;
MAYBE_GC_N(stg_newPinnedByteArrayzh, n);
bytes = n;
/* payload_words is what we will tell the profiler we had to allocate */
payload_words = ROUNDUP_BYTES_TO_WDS(bytes);
/* When we actually allocate memory, we need to allow space for the
header: */
bytes = bytes + SIZEOF_StgArrWords;
/* And we want to align to BA_ALIGN bytes, so we need to allow space
to shift up to BA_ALIGN - 1 bytes: */
bytes = bytes + BA_ALIGN - 1;
/* Now we convert to a number of words: */
words = ROUNDUP_BYTES_TO_WDS(bytes);
("ptr" p) = ccall allocatePinned(MyCapability() "ptr", words);
TICK_ALLOC_PRIM(SIZEOF_StgArrWords,WDS(payload_words),0);
/* Now we need to move p forward so that the payload is aligned
to BA_ALIGN bytes: */
p = p + ((-p - SIZEOF_StgArrWords) & BA_MASK);
SET_HDR(p, stg_ARR_WORDS_info, CCCS);
StgArrWords_bytes(p) = n;
return (p);
}
stg_newAlignedPinnedByteArrayzh ( W_ n, W_ alignment )
{
W_ words, bytes, payload_words;
gcptr p;
again: MAYBE_GC(again);
/* we always supply at least word-aligned memory, so there's no
need to allow extra space for alignment if the requirement is less
than a word. This also prevents mischief with alignment == 0. */
if (alignment <= SIZEOF_W) { alignment = 1; }
bytes = n;
/* payload_words is what we will tell the profiler we had to allocate */
payload_words = ROUNDUP_BYTES_TO_WDS(bytes);
/* When we actually allocate memory, we need to allow space for the
header: */
bytes = bytes + SIZEOF_StgArrWords;
/* And we want to align to <alignment> bytes, so we need to allow space
to shift up to <alignment - 1> bytes: */
bytes = bytes + alignment - 1;
/* Now we convert to a number of words: */
words = ROUNDUP_BYTES_TO_WDS(bytes);
("ptr" p) = ccall allocatePinned(MyCapability() "ptr", words);
TICK_ALLOC_PRIM(SIZEOF_StgArrWords,WDS(payload_words),0);
/* Now we need to move p forward so that the payload is aligned
to <alignment> bytes. Note that we are assuming that
<alignment> is a power of 2, which is technically not guaranteed */
p = p + ((-p - SIZEOF_StgArrWords) & (alignment - 1));
SET_HDR(p, stg_ARR_WORDS_info, CCCS);
StgArrWords_bytes(p) = n;
return (p);
}
stg_newArrayzh ( W_ n /* words */, gcptr init )
{
W_ words, size;
gcptr p, arr;
again: MAYBE_GC(again);
// the mark area contains one byte for each 2^MUT_ARR_PTRS_CARD_BITS words
// in the array, making sure we round up, and then rounding up to a whole
// number of words.
size = n + mutArrPtrsCardWords(n);
words = BYTES_TO_WDS(SIZEOF_StgMutArrPtrs) + size;
("ptr" arr) = ccall allocate(MyCapability() "ptr",words);
TICK_ALLOC_PRIM(SIZEOF_StgMutArrPtrs, WDS(n), 0);
SET_HDR(arr, stg_MUT_ARR_PTRS_DIRTY_info, CCCS);
StgMutArrPtrs_ptrs(arr) = n;
StgMutArrPtrs_size(arr) = size;
// Initialise all elements of the the array with the value in R2
p = arr + SIZEOF_StgMutArrPtrs;
for:
if (p < arr + WDS(words)) {
W_[p] = init;
p = p + WDS(1);
goto for;
}
// Initialise the mark bits with 0
for2:
if (p < arr + WDS(size)) {
W_[p] = 0;
p = p + WDS(1);
goto for2;
}
return (arr);
}
stg_unsafeThawArrayzh ( gcptr arr )
{
// SUBTLETY TO DO WITH THE OLD GEN MUTABLE LIST
//
// A MUT_ARR_PTRS lives on the mutable list, but a MUT_ARR_PTRS_FROZEN
// normally doesn't. However, when we freeze a MUT_ARR_PTRS, we leave
// it on the mutable list for the GC to remove (removing something from
// the mutable list is not easy).
//
// So that we can tell whether a MUT_ARR_PTRS_FROZEN is on the mutable list,
// when we freeze it we set the info ptr to be MUT_ARR_PTRS_FROZEN0
// to indicate that it is still on the mutable list.
//
// So, when we thaw a MUT_ARR_PTRS_FROZEN, we must cope with two cases:
// either it is on a mut_list, or it isn't. We adopt the convention that
// the closure type is MUT_ARR_PTRS_FROZEN0 if it is on the mutable list,
// and MUT_ARR_PTRS_FROZEN otherwise. In fact it wouldn't matter if
// we put it on the mutable list more than once, but it would get scavenged
// multiple times during GC, which would be unnecessarily slow.
//
if (StgHeader_info(arr) != stg_MUT_ARR_PTRS_FROZEN0_info) {
SET_INFO(arr,stg_MUT_ARR_PTRS_DIRTY_info);
recordMutable(arr);
// must be done after SET_INFO, because it ASSERTs closure_MUTABLE()
return (arr);
} else {
SET_INFO(arr,stg_MUT_ARR_PTRS_DIRTY_info);
return (arr);
}
}
stg_newArrayArrayzh ( W_ n /* words */ )
{
W_ words, size;
gcptr p, arr;
MAYBE_GC_N(stg_newArrayArrayzh, n);
// the mark area contains one byte for each 2^MUT_ARR_PTRS_CARD_BITS words
// in the array, making sure we round up, and then rounding up to a whole
// number of words.
size = n + mutArrPtrsCardWords(n);
words = BYTES_TO_WDS(SIZEOF_StgMutArrPtrs) + size;
("ptr" arr) = ccall allocate(MyCapability() "ptr",words);
TICK_ALLOC_PRIM(SIZEOF_StgMutArrPtrs, WDS(n), 0);
SET_HDR(arr, stg_MUT_ARR_PTRS_DIRTY_info, W_[CCCS]);
StgMutArrPtrs_ptrs(arr) = n;
StgMutArrPtrs_size(arr) = size;
// Initialise all elements of the array with a pointer to the new array
p = arr + SIZEOF_StgMutArrPtrs;
for:
if (p < arr + WDS(words)) {
W_[p] = arr;
p = p + WDS(1);
goto for;
}
// Initialise the mark bits with 0
for2:
if (p < arr + WDS(size)) {
W_[p] = 0;
p = p + WDS(1);
goto for2;
}
return (arr);
}
/* -----------------------------------------------------------------------------
MutVar primitives
-------------------------------------------------------------------------- */
stg_newMutVarzh ( gcptr init )
{
W_ mv;
ALLOC_PRIM_P (SIZEOF_StgMutVar, stg_newMutVarzh, init);
mv = Hp - SIZEOF_StgMutVar + WDS(1);
SET_HDR(mv,stg_MUT_VAR_DIRTY_info,CCCS);
StgMutVar_var(mv) = init;
return (mv);
}
stg_casMutVarzh ( gcptr mv, gcptr old, gcptr new )
/* MutVar# s a -> a -> a -> State# s -> (# State#, Int#, a #) */
{
gcptr h;
(h) = ccall cas(mv + SIZEOF_StgHeader + OFFSET_StgMutVar_var,
old, new);
if (h != old) {
return (1,h);
} else {
if (GET_INFO(mv) == stg_MUT_VAR_CLEAN_info) {
ccall dirty_MUT_VAR(BaseReg "ptr", mv "ptr");
}
return (0,h);
}
}
stg_atomicModifyMutVarzh ( gcptr mv, gcptr f )
{
W_ z, x, y, r, h;
/* If x is the current contents of the MutVar#, then
We want to make the new contents point to
(sel_0 (f x))
and the return value is
(sel_1 (f x))
obviously we can share (f x).
z = [stg_ap_2 f x] (max (HS + 2) MIN_UPD_SIZE)
y = [stg_sel_0 z] (max (HS + 1) MIN_UPD_SIZE)
r = [stg_sel_1 z] (max (HS + 1) MIN_UPD_SIZE)
*/
#if MIN_UPD_SIZE > 1
#define THUNK_1_SIZE (SIZEOF_StgThunkHeader + WDS(MIN_UPD_SIZE))
#define TICK_ALLOC_THUNK_1() TICK_ALLOC_UP_THK(WDS(1),WDS(MIN_UPD_SIZE-1))
#else
#define THUNK_1_SIZE (SIZEOF_StgThunkHeader + WDS(1))
#define TICK_ALLOC_THUNK_1() TICK_ALLOC_UP_THK(WDS(1),0)
#endif
#if MIN_UPD_SIZE > 2
#define THUNK_2_SIZE (SIZEOF_StgThunkHeader + WDS(MIN_UPD_SIZE))
#define TICK_ALLOC_THUNK_2() TICK_ALLOC_UP_THK(WDS(2),WDS(MIN_UPD_SIZE-2))
#else
#define THUNK_2_SIZE (SIZEOF_StgThunkHeader + WDS(2))
#define TICK_ALLOC_THUNK_2() TICK_ALLOC_UP_THK(WDS(2),0)
#endif
#define SIZE (THUNK_2_SIZE + THUNK_1_SIZE + THUNK_1_SIZE)
HP_CHK_GEN_TICKY(SIZE);
TICK_ALLOC_THUNK_2();
CCCS_ALLOC(THUNK_2_SIZE);
z = Hp - THUNK_2_SIZE + WDS(1);
SET_HDR(z, stg_ap_2_upd_info, CCCS);
LDV_RECORD_CREATE(z);
StgThunk_payload(z,0) = f;
TICK_ALLOC_THUNK_1();
CCCS_ALLOC(THUNK_1_SIZE);
y = z - THUNK_1_SIZE;
SET_HDR(y, stg_sel_0_upd_info, CCCS);
LDV_RECORD_CREATE(y);
StgThunk_payload(y,0) = z;
TICK_ALLOC_THUNK_1();
CCCS_ALLOC(THUNK_1_SIZE);
r = y - THUNK_1_SIZE;
SET_HDR(r, stg_sel_1_upd_info, CCCS);
LDV_RECORD_CREATE(r);
StgThunk_payload(r,0) = z;
retry:
x = StgMutVar_var(mv);
StgThunk_payload(z,1) = x;
#ifdef THREADED_RTS
(h) = ccall cas(mv + SIZEOF_StgHeader + OFFSET_StgMutVar_var, x, y);
if (h != x) { goto retry; }
#else
StgMutVar_var(mv) = y;
#endif
if (GET_INFO(mv) == stg_MUT_VAR_CLEAN_info) {
ccall dirty_MUT_VAR(BaseReg "ptr", mv "ptr");
}
return (r);
}
/* -----------------------------------------------------------------------------
Weak Pointer Primitives
-------------------------------------------------------------------------- */
STRING(stg_weak_msg,"New weak pointer at %p\n")
stg_mkWeakzh ( gcptr key,
gcptr value,
gcptr finalizer /* or stg_NO_FINALIZER_closure */ )
{
gcptr w;
ALLOC_PRIM (SIZEOF_StgWeak)
w = Hp - SIZEOF_StgWeak + WDS(1);
SET_HDR(w, stg_WEAK_info, CCCS);
StgWeak_key(w) = key;
StgWeak_value(w) = value;
StgWeak_finalizer(w) = finalizer;
StgWeak_cfinalizers(w) = stg_NO_FINALIZER_closure;
ACQUIRE_LOCK(sm_mutex);
StgWeak_link(w) = generation_weak_ptr_list(W_[g0]);
generation_weak_ptr_list(W_[g0]) = w;
RELEASE_LOCK(sm_mutex);
IF_DEBUG(weak, ccall debugBelch(stg_weak_msg,w));
return (w);
}
stg_mkWeakNoFinalizzerzh ( gcptr key, gcptr value )
{
jump stg_mkWeakzh (key, value, stg_NO_FINALIZER_closure);
}
STRING(stg_cfinalizer_msg,"Adding a finalizer to %p\n")
stg_addCFinalizzerToWeakzh ( W_ fptr, // finalizer
W_ ptr,
W_ flag, // has environment (0 or 1)
W_ eptr,
gcptr w )
{
W_ c, info;
("ptr" info) = ccall lockClosure(w "ptr");
if (info == stg_DEAD_WEAK_info) {
// Already dead.
unlockClosure(w, info);
return (0);
}
ALLOC_PRIM (SIZEOF_StgCFinalizerList)
c = Hp - SIZEOF_StgCFinalizerList + WDS(1);
SET_HDR(c, stg_C_FINALIZER_LIST_info, CCCS);
StgCFinalizerList_fptr(c) = fptr;
StgCFinalizerList_ptr(c) = ptr;
StgCFinalizerList_eptr(c) = eptr;
StgCFinalizerList_flag(c) = flag;
StgCFinalizerList_link(c) = StgWeak_cfinalizers(w);
StgWeak_cfinalizers(w) = c;
unlockClosure(w, info);
recordMutable(w);
IF_DEBUG(weak, ccall debugBelch(stg_cfinalizer_msg,w));
return (1);
}
stg_finalizzeWeakzh ( gcptr w )
{
gcptr f, list;
W_ info;
("ptr" info) = ccall lockClosure(w "ptr");
// already dead?
if (info == stg_DEAD_WEAK_info) {
unlockClosure(w, info);
return (0,stg_NO_FINALIZER_closure);
}
f = StgWeak_finalizer(w);
list = StgWeak_cfinalizers(w);
// kill it
#ifdef PROFILING
// @LDV profiling
// A weak pointer is inherently used, so we do not need to call
// LDV_recordDead_FILL_SLOP_DYNAMIC():
// LDV_recordDead_FILL_SLOP_DYNAMIC((StgClosure *)w);
// or, LDV_recordDead():
// LDV_recordDead((StgClosure *)w, sizeofW(StgWeak) - sizeofW(StgProfHeader));
// Furthermore, when PROFILING is turned on, dead weak pointers are exactly as
// large as weak pointers, so there is no need to fill the slop, either.
// See stg_DEAD_WEAK_info in StgMiscClosures.hc.
#endif
//
// Todo: maybe use SET_HDR() and remove LDV_recordCreate()?
//
unlockClosure(w, stg_DEAD_WEAK_info);
LDV_RECORD_CREATE(w);
if (list != stg_NO_FINALIZER_closure) {
ccall runCFinalizers(list);
}
/* return the finalizer */
if (f == stg_NO_FINALIZER_closure) {
return (0,stg_NO_FINALIZER_closure);
} else {
return (1,f);
}
}
stg_deRefWeakzh ( gcptr w )
{
W_ code, info;
gcptr val;
info = GET_INFO(w);
if (info == stg_WHITEHOLE_info) {
// w is locked by another thread. Now it's not immediately clear if w is
// alive or not. We use lockClosure to wait for the info pointer to become
// something other than stg_WHITEHOLE_info.
("ptr" info) = ccall lockClosure(w "ptr");
unlockClosure(w, info);
}
if (info == stg_WEAK_info) {
code = 1;
val = StgWeak_value(w);
} else {
code = 0;
val = w;
}
return (code,val);
}
/* -----------------------------------------------------------------------------
Floating point operations.
-------------------------------------------------------------------------- */
stg_decodeFloatzuIntzh ( F_ arg )
{
W_ p;
W_ mp_tmp1;
W_ mp_tmp_w;
STK_CHK_GEN_N (WDS(2));
mp_tmp1 = Sp - WDS(1);
mp_tmp_w = Sp - WDS(2);
/* Perform the operation */
ccall __decodeFloat_Int(mp_tmp1 "ptr", mp_tmp_w "ptr", arg);
/* returns: (Int# (mantissa), Int# (exponent)) */
return (W_[mp_tmp1], W_[mp_tmp_w]);
}
stg_decodeDoublezu2Intzh ( D_ arg )
{
W_ p;
W_ mp_tmp1;
W_ mp_tmp2;
W_ mp_result1;
W_ mp_result2;
STK_CHK_GEN_N (WDS(4));
mp_tmp1 = Sp - WDS(1);
mp_tmp2 = Sp - WDS(2);
mp_result1 = Sp - WDS(3);
mp_result2 = Sp - WDS(4);
/* Perform the operation */
ccall __decodeDouble_2Int(mp_tmp1 "ptr", mp_tmp2 "ptr",
mp_result1 "ptr", mp_result2 "ptr",
arg);
/* returns:
(Int# (mant sign), Word# (mant high), Word# (mant low), Int# (expn)) */
return (W_[mp_tmp1], W_[mp_tmp2], W_[mp_result1], W_[mp_result2]);
}
/* -----------------------------------------------------------------------------
* Concurrency primitives
* -------------------------------------------------------------------------- */
stg_forkzh ( gcptr closure )
{
MAYBE_GC_P(stg_forkzh, closure);
gcptr threadid;
("ptr" threadid) = ccall createIOThread( MyCapability() "ptr",
RtsFlags_GcFlags_initialStkSize(RtsFlags),
closure "ptr");
/* start blocked if the current thread is blocked */
StgTSO_flags(threadid) = %lobits16(
TO_W_(StgTSO_flags(threadid)) |
TO_W_(StgTSO_flags(CurrentTSO)) & (TSO_BLOCKEX | TSO_INTERRUPTIBLE));
ccall scheduleThread(MyCapability() "ptr", threadid "ptr");
// context switch soon, but not immediately: we don't want every
// forkIO to force a context-switch.
Capability_context_switch(MyCapability()) = 1 :: CInt;
return (threadid);
}
stg_forkOnzh ( W_ cpu, gcptr closure )
{
again: MAYBE_GC(again);
gcptr threadid;
("ptr" threadid) = ccall createIOThread( MyCapability() "ptr",
RtsFlags_GcFlags_initialStkSize(RtsFlags),
closure "ptr");
/* start blocked if the current thread is blocked */
StgTSO_flags(threadid) = %lobits16(
TO_W_(StgTSO_flags(threadid)) |
TO_W_(StgTSO_flags(CurrentTSO)) & (TSO_BLOCKEX | TSO_INTERRUPTIBLE));
ccall scheduleThreadOn(MyCapability() "ptr", cpu, threadid "ptr");
// context switch soon, but not immediately: we don't want every
// forkIO to force a context-switch.
Capability_context_switch(MyCapability()) = 1 :: CInt;
return (threadid);
}
stg_yieldzh ()
{
// when we yield to the scheduler, we have to tell it to put the
// current thread to the back of the queue by setting the
// context_switch flag. If we don't do this, it will run the same
// thread again.
Capability_context_switch(MyCapability()) = 1 :: CInt;
jump stg_yield_noregs();
}
stg_myThreadIdzh ()
{
return (CurrentTSO);
}
stg_labelThreadzh ( gcptr threadid, W_ addr )
{
#if defined(DEBUG) || defined(TRACING) || defined(DTRACE)
ccall labelThread(MyCapability() "ptr", threadid "ptr", addr "ptr");
#endif
return ();
}
stg_isCurrentThreadBoundzh (/* no args */)
{
W_ r;
(r) = ccall isThreadBound(CurrentTSO);
return (r);
}
stg_threadStatuszh ( gcptr tso )
{
W_ why_blocked;
W_ what_next;
W_ ret, cap, locked;
what_next = TO_W_(StgTSO_what_next(tso));
why_blocked = TO_W_(StgTSO_why_blocked(tso));
// Note: these two reads are not atomic, so they might end up
// being inconsistent. It doesn't matter, since we
// only return one or the other. If we wanted to return the
// contents of block_info too, then we'd have to do some synchronisation.
if (what_next == ThreadComplete) {
ret = 16; // NB. magic, matches up with GHC.Conc.threadStatus
} else {
if (what_next == ThreadKilled) {
ret = 17;
} else {
ret = why_blocked;
}
}
cap = TO_W_(Capability_no(StgTSO_cap(tso)));
if ((TO_W_(StgTSO_flags(tso)) & TSO_LOCKED) != 0) {
locked = 1;
} else {
locked = 0;
}
return (ret,cap,locked);
}
/* -----------------------------------------------------------------------------
* TVar primitives
* -------------------------------------------------------------------------- */
// Catch retry frame -----------------------------------------------------------
#define CATCH_RETRY_FRAME_FIELDS(w_,p_,info_ptr, \
p1, p2, \
running_alt_code, \
first_code, \
alt_code) \
w_ info_ptr, \
PROF_HDR_FIELDS(w_,p1,p2) \
w_ running_alt_code, \
p_ first_code, \
p_ alt_code
INFO_TABLE_RET(stg_catch_retry_frame, CATCH_RETRY_FRAME,
CATCH_RETRY_FRAME_FIELDS(W_,P_,
info_ptr, p1, p2,
running_alt_code,
first_code,
alt_code))
return (P_ ret)
{
W_ r;
gcptr trec, outer, arg;
trec = StgTSO_trec(CurrentTSO);
outer = StgTRecHeader_enclosing_trec(trec);
(r) = ccall stmCommitNestedTransaction(MyCapability() "ptr", trec "ptr");
if (r != 0) {
// Succeeded (either first branch or second branch)
StgTSO_trec(CurrentTSO) = outer;
return (ret);
} else {
// Did not commit: re-execute
P_ new_trec;
("ptr" new_trec) = ccall stmStartTransaction(MyCapability() "ptr",
outer "ptr");
StgTSO_trec(CurrentTSO) = new_trec;
if (running_alt_code != 0) {
jump stg_ap_v_fast
(CATCH_RETRY_FRAME_FIELDS(,,info_ptr, p1, p2,
running_alt_code,
first_code,
alt_code))
(alt_code);
} else {
jump stg_ap_v_fast
(CATCH_RETRY_FRAME_FIELDS(,,info_ptr, p1, p2,
running_alt_code,
first_code,
alt_code))
(first_code);
}
}
}
// Atomically frame ------------------------------------------------------------
// This must match StgAtomicallyFrame in Closures.h
#define ATOMICALLY_FRAME_FIELDS(w_,p_,info_ptr,p1,p2,code,next,result) \
w_ info_ptr, \
PROF_HDR_FIELDS(w_,p1,p2) \
p_ code, \
p_ next, \
p_ result
INFO_TABLE_RET(stg_atomically_frame, ATOMICALLY_FRAME,
// layout of the frame, and bind the field names
ATOMICALLY_FRAME_FIELDS(W_,P_,
info_ptr, p1, p2,
code,
next_invariant,
frame_result))
return (P_ result) // value returned to the frame
{
W_ valid;
gcptr trec, outer, next_invariant, q;
trec = StgTSO_trec(CurrentTSO);
outer = StgTRecHeader_enclosing_trec(trec);
if (outer == NO_TREC) {
/* First time back at the atomically frame -- pick up invariants */
("ptr" next_invariant) =
ccall stmGetInvariantsToCheck(MyCapability() "ptr", trec "ptr");
frame_result = result;
} else {
/* Second/subsequent time back at the atomically frame -- abort the
* tx that's checking the invariant and move on to the next one */
StgTSO_trec(CurrentTSO) = outer;
StgInvariantCheckQueue_my_execution(next_invariant) = trec;
ccall stmAbortTransaction(MyCapability() "ptr", trec "ptr");
/* Don't free trec -- it's linked from q and will be stashed in the
* invariant if we eventually commit. */
next_invariant =
StgInvariantCheckQueue_next_queue_entry(next_invariant);
trec = outer;
}
if (next_invariant != END_INVARIANT_CHECK_QUEUE) {
/* We can't commit yet: another invariant to check */
("ptr" trec) = ccall stmStartTransaction(MyCapability() "ptr", trec "ptr");
StgTSO_trec(CurrentTSO) = trec;
q = StgInvariantCheckQueue_invariant(next_invariant);
jump stg_ap_v_fast
(ATOMICALLY_FRAME_FIELDS(,,info_ptr,p1,p2,
code,next_invariant,frame_result))
(StgAtomicInvariant_code(q));
} else {
/* We've got no more invariants to check, try to commit */
(valid) = ccall stmCommitTransaction(MyCapability() "ptr", trec "ptr");
if (valid != 0) {
/* Transaction was valid: commit succeeded */
StgTSO_trec(CurrentTSO) = NO_TREC;
return (frame_result);
} else {
/* Transaction was not valid: try again */
("ptr" trec) = ccall stmStartTransaction(MyCapability() "ptr", NO_TREC "ptr");
StgTSO_trec(CurrentTSO) = trec;
next_invariant = END_INVARIANT_CHECK_QUEUE;
jump stg_ap_v_fast
// push the StgAtomicallyFrame again: the code generator is
// clever enough to only assign the fields that have changed.
(ATOMICALLY_FRAME_FIELDS(,,info_ptr,p1,p2,
code,next_invariant,frame_result))
(code);
}
}
}
INFO_TABLE_RET(stg_atomically_waiting_frame, ATOMICALLY_FRAME,
// layout of the frame, and bind the field names
ATOMICALLY_FRAME_FIELDS(W_,P_,
info_ptr, p1, p2,
code,
next_invariant,
frame_result))
return (/* no return values */)
{
W_ trec, valid;
/* The TSO is currently waiting: should we stop waiting? */
(valid) = ccall stmReWait(MyCapability() "ptr", CurrentTSO "ptr");
if (valid != 0) {
/* Previous attempt is still valid: no point trying again yet */
jump stg_block_noregs
(ATOMICALLY_FRAME_FIELDS(,,info_ptr, p1, p2,
code,next_invariant,frame_result))
();
} else {
/* Previous attempt is no longer valid: try again */
("ptr" trec) = ccall stmStartTransaction(MyCapability() "ptr", NO_TREC "ptr");
StgTSO_trec(CurrentTSO) = trec;
// change the frame header to stg_atomically_frame_info
jump stg_ap_v_fast
(ATOMICALLY_FRAME_FIELDS(,,stg_atomically_frame_info, p1, p2,
code,next_invariant,frame_result))
(code);
}
}
// STM catch frame -------------------------------------------------------------
/* 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.
*/
#define CATCH_STM_FRAME_FIELDS(w_,p_,info_ptr,p1,p2,code,handler) \
w_ info_ptr, \
PROF_HDR_FIELDS(w_,p1,p2) \
p_ code, \
p_ handler
INFO_TABLE_RET(stg_catch_stm_frame, CATCH_STM_FRAME,
// layout of the frame, and bind the field names
CATCH_STM_FRAME_FIELDS(W_,P_,info_ptr,p1,p2,code,handler))
return (P_ ret)
{
W_ r, trec, outer;
trec = StgTSO_trec(CurrentTSO);
outer = StgTRecHeader_enclosing_trec(trec);
(r) = ccall stmCommitNestedTransaction(MyCapability() "ptr", trec "ptr");
if (r != 0) {
/* Commit succeeded */
StgTSO_trec(CurrentTSO) = outer;
return (ret);
} else {
/* Commit failed */
W_ new_trec;
("ptr" new_trec) = ccall stmStartTransaction(MyCapability() "ptr", outer "ptr");
StgTSO_trec(CurrentTSO) = new_trec;
jump stg_ap_v_fast
(CATCH_STM_FRAME_FIELDS(,,info_ptr,p1,p2,code,handler))
(code);
}
}
// Primop definition -----------------------------------------------------------
stg_atomicallyzh (P_ stm)
{
P_ old_trec;
P_ new_trec;
P_ code, next_invariant, frame_result;
// stmStartTransaction may allocate
MAYBE_GC_P(stg_atomicallyzh, stm);
STK_CHK_GEN();
old_trec = StgTSO_trec(CurrentTSO);
/* Nested transactions are not allowed; raise an exception */
if (old_trec != NO_TREC) {
jump stg_raisezh(base_ControlziExceptionziBase_nestedAtomically_closure);
}
code = stm;
next_invariant = END_INVARIANT_CHECK_QUEUE;
frame_result = NO_TREC;
/* Start the memory transcation */
("ptr" new_trec) = ccall stmStartTransaction(MyCapability() "ptr", old_trec "ptr");
StgTSO_trec(CurrentTSO) = new_trec;
jump stg_ap_v_fast
(ATOMICALLY_FRAME_FIELDS(,,stg_atomically_frame_info, CCCS, 0,
code,next_invariant,frame_result))
(stm);
}
// A closure representing "atomically x". This is used when a thread
// inside a transaction receives an asynchronous exception; see #5866.
// It is somewhat similar to the stg_raise closure.
//
INFO_TABLE(stg_atomically,1,0,THUNK_1_0,"atomically","atomically")
(P_ thunk)
{
jump stg_atomicallyzh(StgThunk_payload(thunk,0));
}
stg_catchSTMzh (P_ code /* :: STM a */,
P_ handler /* :: Exception -> STM a */)
{
STK_CHK_GEN();
/* Start a nested transaction to run the body of the try block in */
W_ cur_trec;
W_ new_trec;
cur_trec = StgTSO_trec(CurrentTSO);
("ptr" new_trec) = ccall stmStartTransaction(MyCapability() "ptr",
cur_trec "ptr");
StgTSO_trec(CurrentTSO) = new_trec;
jump stg_ap_v_fast
(CATCH_STM_FRAME_FIELDS(,,stg_catch_stm_frame_info, CCCS, 0,
code, handler))
(code);
}
stg_catchRetryzh (P_ first_code, /* :: STM a */
P_ alt_code /* :: STM a */)
{
W_ new_trec;
// stmStartTransaction may allocate
MAYBE_GC_PP (stg_catchRetryzh, first_code, alt_code);
STK_CHK_GEN();
/* Start a nested transaction within which to run the first code */
("ptr" new_trec) = ccall stmStartTransaction(MyCapability() "ptr",
StgTSO_trec(CurrentTSO) "ptr");
StgTSO_trec(CurrentTSO) = new_trec;
// push the CATCH_RETRY stack frame, and apply first_code to realWorld#
jump stg_ap_v_fast
(CATCH_RETRY_FRAME_FIELDS(,, stg_catch_retry_frame_info, CCCS, 0,
0, /* not running_alt_code */
first_code,
alt_code))
(first_code);
}
stg_retryzh /* no arg list: explicit stack layout */
{
W_ frame_type;
W_ frame;
W_ trec;
W_ outer;
W_ r;
// STM operations may allocate
MAYBE_GC_ (stg_retryzh); // NB. not MAYBE_GC(), we cannot make a
// function call in an explicit-stack proc
// Find the enclosing ATOMICALLY_FRAME or CATCH_RETRY_FRAME
retry_pop_stack:
SAVE_THREAD_STATE();
(frame_type) = ccall findRetryFrameHelper(MyCapability(), CurrentTSO "ptr");
LOAD_THREAD_STATE();
frame = Sp;
trec = StgTSO_trec(CurrentTSO);
outer = StgTRecHeader_enclosing_trec(trec);
if (frame_type == CATCH_RETRY_FRAME) {
// The retry reaches a CATCH_RETRY_FRAME before the atomic frame
ASSERT(outer != NO_TREC);
// Abort the transaction attempting the current branch