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foreach.c
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foreach.c
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/* Copyright (C) 2016,2019-2020 Matthew Fluet.
* Copyright (C) 1999-2007 Henry Cejtin, Matthew Fluet, Suresh
* Jagannathan, and Stephen Weeks.
* Copyright (C) 1997-2000 NEC Research Institute.
*
* MLton is released under a HPND-style license.
* See the file MLton-LICENSE for details.
*/
void callIfIsObjptr (GC_state s, GC_foreachObjptrClosure f, objptr *opp) {
if (isObjptr (*opp))
f->fun (s, opp, f->env);
}
/* foreachGlobalObjptr (s, f)
*
* Apply f to each global object pointer into the heap.
*/
void foreachGlobalObjptr (GC_state s, GC_foreachObjptrClosure f) {
for (unsigned int i = 0; i < s->globalsLength; ++i) {
if (DEBUG_DETAILED)
fprintf (stderr, "foreachGlobal %u\n", i);
callIfIsObjptr (s, f, &s->globals [i]);
}
foreachObjptrInStaticHeap (s, &s->staticHeaps.root, f, TRUE);
if (DEBUG_DETAILED)
fprintf (stderr, "foreachGlobal threads\n");
callIfIsObjptr (s, f, &s->callFromCHandlerThread);
callIfIsObjptr (s, f, &s->currentThread);
callIfIsObjptr (s, f, &s->savedThread);
callIfIsObjptr (s, f, &s->signalHandlerThread);
}
/* foreachObjptrInObject (s, p, f, skipWeaks)
*
* Applies f to each object pointer in the object pointed to by p.
* Returns pointer to the end of object, i.e. just past object.
*
* If skipWeaks, then the object pointer in weak objects is skipped.
*/
pointer foreachObjptrInObject (GC_state s, pointer p,
GC_foreachObjptrClosure f, bool skipWeaks) {
GC_header header;
uint16_t bytesNonObjptrs;
uint16_t numObjptrs;
GC_objectTypeTag tag;
header = getHeader (p);
splitHeader(s, header, &tag, NULL, &bytesNonObjptrs, &numObjptrs);
if (DEBUG_DETAILED)
fprintf (stderr,
"foreachObjptrInObject ("FMTPTR")"
" header = "FMTHDR
" tag = %s"
" bytesNonObjptrs = %d"
" numObjptrs = %d\n",
(uintptr_t)p, header, objectTypeTagToString (tag),
bytesNonObjptrs, numObjptrs);
if (NORMAL_TAG == tag) {
p += bytesNonObjptrs;
pointer max = p + (numObjptrs * OBJPTR_SIZE);
/* Apply f to all internal pointers. */
for ( ; p < max; p += OBJPTR_SIZE) {
if (DEBUG_DETAILED)
fprintf (stderr,
" p = "FMTPTR" *p = "FMTOBJPTR"\n",
(uintptr_t)p, *(objptr*)p);
callIfIsObjptr (s, f, (objptr*)p);
}
} else if (WEAK_TAG == tag) {
p += bytesNonObjptrs;
if (1 == numObjptrs) {
if (not skipWeaks)
callIfIsObjptr (s, f, (objptr*)p);
p += OBJPTR_SIZE;
}
} else if (SEQUENCE_TAG == tag) {
size_t bytesPerElement;
size_t dataBytes;
pointer last;
GC_sequenceLength numElements;
numElements = getSequenceLength (p);
bytesPerElement = bytesNonObjptrs + (numObjptrs * OBJPTR_SIZE);
dataBytes = numElements * bytesPerElement;
if (0 == numObjptrs) {
/* No objptrs to process. */
;
} else {
last = p + dataBytes;
if (0 == bytesNonObjptrs)
/* Sequence with only pointers. */
for ( ; p < last; p += OBJPTR_SIZE)
callIfIsObjptr (s, f, (objptr*)p);
else {
/* Sequence with a mix of pointers and non-pointers. */
size_t bytesObjptrs;
bytesObjptrs = numObjptrs * OBJPTR_SIZE;
/* For each sequence element. */
for ( ; p < last; ) {
pointer next;
/* Skip the non-pointers. */
p += bytesNonObjptrs;
next = p + bytesObjptrs;
/* For each internal pointer. */
for ( ; p < next; p += OBJPTR_SIZE)
callIfIsObjptr (s, f, (objptr*)p);
}
}
assert (p == last);
p -= dataBytes;
}
p += alignWithExtra (s, dataBytes, GC_SEQUENCE_METADATA_SIZE);
} else { /* stack */
GC_stack stack;
pointer top, bottom;
unsigned int i;
GC_returnAddress returnAddress;
GC_frameInfo frameInfo;
GC_frameOffsets frameOffsets;
assert (STACK_TAG == tag);
stack = (GC_stack)p;
bottom = getStackBottom (s, stack);
top = getStackTop (s, stack);
if (DEBUG) {
fprintf (stderr, " bottom = "FMTPTR" top = "FMTPTR"\n",
(uintptr_t)bottom, (uintptr_t)top);
}
assert (stack->used <= stack->reserved);
while (top > bottom) {
/* Invariant: top points just past a "return address". */
returnAddress = *((GC_returnAddress*)(top - GC_RETURNADDRESS_SIZE));
if (DEBUG) {
fprintf (stderr, " top = "FMTPTR" return address = "FMTRA"\n",
(uintptr_t)top, returnAddress);
}
frameInfo = getFrameInfoFromReturnAddress (s, returnAddress);
frameOffsets = frameInfo->offsets;
top -= frameInfo->size;
for (i = 0 ; i < frameOffsets[0] ; ++i) {
if (DEBUG)
fprintf(stderr, " offset %"PRIx16" address "FMTOBJPTR"\n",
frameOffsets[i + 1], *(objptr*)(top + frameOffsets[i + 1]));
callIfIsObjptr (s, f, (objptr*)(top + frameOffsets[i + 1]));
}
}
assert(top == bottom);
p += sizeof (struct GC_stack) + stack->reserved;
}
return p;
}
/* foreachObjptrInRange (s, front, back, f, skipWeaks)
*
* Apply f to each pointer between front and *back, which should be a
* contiguous sequence of objects, where front points at the beginning
* of the first object and *back points just past the end of the last
* object. f may increase *back (for example, this is done by
* forward). foreachObjptrInRange returns a pointer to the end of
* the last object it visits.
*
* If skipWeaks, then the object pointer in weak objects is skipped.
*/
pointer foreachObjptrInRange (GC_state s, pointer front, pointer *back,
GC_foreachObjptrClosure f, bool skipWeaks) {
pointer b;
assert (isFrontierAligned (s, front));
if (DEBUG_DETAILED)
fprintf (stderr,
"foreachObjptrInRange front = "FMTPTR" *back = "FMTPTR"\n",
(uintptr_t)front, (uintptr_t)(*back));
b = *back;
assert (front <= b);
while (front < b) {
while (front < b) {
assert (isAligned ((size_t)front, GC_MODEL_MINALIGN));
if (DEBUG_DETAILED)
fprintf (stderr,
" front = "FMTPTR" *back = "FMTPTR"\n",
(uintptr_t)front, (uintptr_t)(*back));
pointer p = advanceToObjectData (s, front);
assert (isAligned ((size_t)p, s->alignment));
front = foreachObjptrInObject (s, p, f, skipWeaks);
}
b = *back;
}
return front;
}
void foreachObjptrInStaticHeap (GC_state s,
struct GC_staticHeap *staticHeap,
GC_foreachObjptrClosure f,
bool skipWeaks) {
pointer front = alignFrontier (s, staticHeap->start);
pointer back = staticHeap->start + staticHeap->size;
foreachObjptrInRange (s, front, &back, f, skipWeaks);
}
/* Apply f to the frame index of each frame in the current thread's stack. */
void foreachStackFrame (GC_state s, GC_foreachStackFrameClosure f) {
pointer bottom;
GC_frameIndex frameIndex;
GC_frameInfo frameInfo;
GC_returnAddress returnAddress;
pointer top;
if (DEBUG_PROFILE)
fprintf (stderr, "foreachStackFrame\n");
bottom = getStackBottom (s, getStackCurrent(s));
if (DEBUG_PROFILE)
fprintf (stderr, " bottom = "FMTPTR" top = "FMTPTR".\n",
(uintptr_t)bottom, (uintptr_t)s->stackTop);
top = s->stackTop;
while (top > bottom) {
returnAddress = *((GC_returnAddress*)(top - GC_RETURNADDRESS_SIZE));
frameIndex = getFrameIndexFromReturnAddress (s, returnAddress);
if (DEBUG_PROFILE)
fprintf (stderr, "top = "FMTPTR" frameIndex = "FMTFI"\n",
(uintptr_t)top, frameIndex);
unless (frameIndex < s->frameInfosLength)
die ("top = "FMTPTR" returnAddress = "FMTRA" frameIndex = "FMTFI"\n",
(uintptr_t)top, (uintptr_t)returnAddress, frameIndex);
frameInfo = &(s->frameInfos[frameIndex]);
assert (frameInfo->size > 0);
top -= frameInfo->size;
f->fun (s, frameIndex, frameInfo, top, f->env);
}
if (DEBUG_PROFILE)
fprintf (stderr, "done foreachStackFrame\n");
}