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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Heap map, 32-bit version
// See malloc.h and mheap.c for overview.
#include "runtime.h"
#include "malloc.h"
#if __SIZEOF_POINTER__ == 4
// 3-level radix tree mapping page ids to Span*.
void
runtime_MHeapMap_Init(MHeapMap *m, void *(*allocator)(uintptr))
{
m->allocator = allocator;
}
MSpan*
runtime_MHeapMap_Get(MHeapMap *m, PageID k)
{
int32 i1, i2;
i2 = k & MHeapMap_Level2Mask;
k >>= MHeapMap_Level2Bits;
i1 = k & MHeapMap_Level1Mask;
k >>= MHeapMap_Level1Bits;
if(k != 0)
runtime_throw("MHeapMap_Get");
return m->p[i1]->s[i2];
}
MSpan*
runtime_MHeapMap_GetMaybe(MHeapMap *m, PageID k)
{
int32 i1, i2;
MHeapMapNode2 *p2;
i2 = k & MHeapMap_Level2Mask;
k >>= MHeapMap_Level2Bits;
i1 = k & MHeapMap_Level1Mask;
k >>= MHeapMap_Level1Bits;
if(k != 0)
runtime_throw("MHeapMap_Get");
p2 = m->p[i1];
if(p2 == nil)
return nil;
return p2->s[i2];
}
void
runtime_MHeapMap_Set(MHeapMap *m, PageID k, MSpan *s)
{
int32 i1, i2;
i2 = k & MHeapMap_Level2Mask;
k >>= MHeapMap_Level2Bits;
i1 = k & MHeapMap_Level1Mask;
k >>= MHeapMap_Level1Bits;
if(k != 0)
runtime_throw("MHeapMap_Set");
m->p[i1]->s[i2] = s;
}
// Allocate the storage required for entries [k, k+1, ..., k+len-1]
// so that Get and Set calls need not check for nil pointers.
bool
runtime_MHeapMap_Preallocate(MHeapMap *m, PageID k, uintptr len)
{
uintptr end;
int32 i1;
MHeapMapNode2 *p2;
end = k+len;
while(k < end) {
if((k >> MHeapMap_TotalBits) != 0)
return false;
i1 = (k >> MHeapMap_Level2Bits) & MHeapMap_Level1Mask;
// first-level pointer
if(m->p[i1] == nil) {
p2 = m->allocator(sizeof *p2);
if(p2 == nil)
return false;
mstats.heapmap_sys += sizeof *p2;
m->p[i1] = p2;
}
// advance key past this leaf node
k = ((k >> MHeapMap_Level2Bits) + 1) << MHeapMap_Level2Bits;
}
return true;
}
#endif /* __SIZEOF_POINTER__ == 4 */
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