7194633: G1: Assertion and guarantee failures in block offset table
Summary: Add detailed error messages to assertions and guarantees in G1's block offset table.
Reviewed-by: ysr, brutisso
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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
#include "gc_implementation/g1/g1BlockOffsetTable.hpp"
#include "memory/space.hpp"
inline HeapWord* G1BlockOffsetTable::block_start(const void* addr) {
if (addr >= _bottom && addr < _end) {
return block_start_unsafe(addr);
} else {
return NULL;
}
}
inline HeapWord*
G1BlockOffsetTable::block_start_const(const void* addr) const {
if (addr >= _bottom && addr < _end) {
return block_start_unsafe_const(addr);
} else {
return NULL;
}
}
inline size_t G1BlockOffsetSharedArray::index_for(const void* p) const {
char* pc = (char*)p;
assert(pc >= (char*)_reserved.start() &&
pc < (char*)_reserved.end(),
err_msg("p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
p, (char*)_reserved.start(), (char*)_reserved.end()));
size_t delta = pointer_delta(pc, _reserved.start(), sizeof(char));
size_t result = delta >> LogN;
check_index(result, "bad index from address");
return result;
}
inline HeapWord*
G1BlockOffsetSharedArray::address_for_index(size_t index) const {
check_index(index, "index out of range");
HeapWord* result = _reserved.start() + (index << LogN_words);
assert(result >= _reserved.start() && result < _reserved.end(),
err_msg("bad address from index result " PTR_FORMAT
" _reserved.start() " PTR_FORMAT " _reserved.end() "
PTR_FORMAT,
result, _reserved.start(), _reserved.end()));
return result;
}
inline HeapWord*
G1BlockOffsetArray::block_at_or_preceding(const void* addr,
bool has_max_index,
size_t max_index) const {
assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
size_t index = _array->index_for(addr);
// We must make sure that the offset table entry we use is valid. If
// "addr" is past the end, start at the last known one and go forward.
if (has_max_index) {
index = MIN2(index, max_index);
}
HeapWord* q = _array->address_for_index(index);
uint offset = _array->offset_array(index); // Extend u_char to uint.
while (offset >= N_words) {
// The excess of the offset from N_words indicates a power of Base
// to go back by.
size_t n_cards_back = BlockOffsetArray::entry_to_cards_back(offset);
q -= (N_words * n_cards_back);
assert(q >= _sp->bottom(), "Went below bottom!");
index -= n_cards_back;
offset = _array->offset_array(index);
}
assert(offset < N_words, "offset too large");
q -= offset;
return q;
}
inline HeapWord*
G1BlockOffsetArray::
forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n,
const void* addr) const {
if (csp() != NULL) {
if (addr >= csp()->top()) return csp()->top();
while (n <= addr) {
q = n;
oop obj = oop(q);
if (obj->klass_or_null() == NULL) return q;
n += obj->size();
}
} else {
while (n <= addr) {
q = n;
oop obj = oop(q);
if (obj->klass_or_null() == NULL) return q;
n += _sp->block_size(q);
}
}
assert(q <= n, "wrong order for q and addr");
assert(addr < n, "wrong order for addr and n");
return q;
}
inline HeapWord*
G1BlockOffsetArray::forward_to_block_containing_addr(HeapWord* q,
const void* addr) {
if (oop(q)->klass_or_null() == NULL) return q;
HeapWord* n = q + _sp->block_size(q);
// In the normal case, where the query "addr" is a card boundary, and the
// offset table chunks are the same size as cards, the block starting at
// "q" will contain addr, so the test below will fail, and we'll fall
// through quickly.
if (n <= addr) {
q = forward_to_block_containing_addr_slow(q, n, addr);
}
assert(q <= addr, "wrong order for current and arg");
return q;
}
//////////////////////////////////////////////////////////////////////////
// BlockOffsetArrayNonContigSpace inlines
//////////////////////////////////////////////////////////////////////////
inline void G1BlockOffsetArray::freed(HeapWord* blk_start, HeapWord* blk_end) {
// Verify that the BOT shows [blk_start, blk_end) to be one block.
verify_single_block(blk_start, blk_end);
// adjust _unallocated_block upward or downward
// as appropriate
if (BlockOffsetArrayUseUnallocatedBlock) {
assert(_unallocated_block <= _end,
"Inconsistent value for _unallocated_block");
if (blk_end >= _unallocated_block && blk_start <= _unallocated_block) {
// CMS-specific note: a block abutting _unallocated_block to
// its left is being freed, a new block is being added or
// we are resetting following a compaction
_unallocated_block = blk_start;
}
}
}
inline void G1BlockOffsetArray::freed(HeapWord* blk, size_t size) {
freed(blk, blk + size);
}
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP