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Adding poolsingleaccess

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Copied from Perforce
 Change: 19441
 ServerID: perforce.ravenbrook.com
This commit is contained in:
David Jones 1998-04-20 15:18:18 +01:00
parent df9fbb6a11
commit 0e2af17037
1 changed files with 80 additions and 2 deletions
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82
mps/src/pool.c
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@ -1,6 +1,6 @@
/* impl.c.pool: POOL IMPLEMENTATION
*
* $HopeName: MMsrc!pool.c(trunk.50) $
* $HopeName: MMsrc!pool.c(trunk.51) $
* Copyright (C) 1997. Harlequin Group plc. All rights reserved.
*
* READERSHIP
@ -37,7 +37,7 @@
#include "mpm.h"
SRCID(pool, "$HopeName: MMsrc!pool.c(trunk.50) $");
SRCID(pool, "$HopeName: MMsrc!pool.c(trunk.51) $");
Bool PoolClassCheck(PoolClass class)
@ -767,6 +767,7 @@ Res PoolSegAccess(Pool pool, Seg seg, Addr addr,
AVER(addr < SegLimit(seg));
AVER(SegPool(seg) == pool);
/* can't check AccessSet as there is no Check method */
/* can't check context as there is no Check method */
UNUSED(addr);
UNUSED(context);
@ -774,6 +775,83 @@ Res PoolSegAccess(Pool pool, Seg seg, Addr addr,
return ResOK;
}
/* SingleAccess
*
* Handles page faults by attempting emulation. If the faulting
* instruction cannot be emulated then this function returns ResFAIL.
*
* Due to the assumptions made below, pool classes should only use
* this function if all words in an object are tagged or traceable.
*
* .single-access.assume.ref: It currently assumes that the address
* being faulted on contains a plain reference or a tagged non-reference.
* .single-access.improve.format: * later this will be abstracted
* through the cleint object format interface, so that
* no such assumption is necessary.
*/
Res PoolSingleAccess(Pool pool, Seg seg, Addr addr,
AccessSet mode, MutatorFaultContext context)
{
Arena arena;
AVERT(Pool, pool);
AVERT(Seg, seg);
AVER(SegBase(seg) <= addr);
AVER(addr < SegLimit(seg));
AVER(SegPool(seg) == pool);
/* can't check AccessSet as there is no Check method */
/* can't check context as there is no Check method */
arena = PoolArena(pool);
if(ProtCanStepInstruction(context)) {
Ref ref;
Res res;
ShieldExpose(arena, seg);
if(mode & SegSM(seg) & AccessREAD) {
/* read access */
/* .single-access.assume.ref */
/* .single-access.improve.format */
ref = *(Ref *)addr;
/* Check that the reference is aligned to a word boundary */
/* (we assume it is not a reference otherwise) */
if(WordIsAligned((Word)ref, sizeof(Word))) {
TraceSet ts;
ts = arena->flippedTraces;
/* See the note in TraceSegAccess about using RankEXACT here */
/* (impl.c.trace.scan.conservative) */
res = TraceScanSingleRef(ts, arena, seg, RankEXACT, (Ref *)addr);
if(res != ResOK) {
TraceId ti;
/* enter emergency tracing mode */
for(ti = 0; ti < TRACE_MAX; ++ti) {
ArenaTrace(arena, ti)->emergency = TRUE;
}
}
res = TraceScanSingleRef(ts, arena, seg, RankEXACT, (Ref *)addr);
AVER(res == ResOK);
}
}
res = ProtStepInstruction(context);
AVER(res == ResOK);
/* update SegSummary according to the possibly changed reference */
ref = *(Ref *)addr;
SegSetSummary(seg, RefSetAdd(arena, SegSummary(seg), ref));
ShieldCover(arena, seg);
return ResOK;
} else {
/* couldn't single-step instruction */
return ResFAIL;
}
}
Res PoolTrivWhiten(Pool pool, Trace trace, Seg seg)
{
AVERT(Pool, pool);