1663
1664
1665 //--------------------------------find_alias_type------------------------------
1666 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1667 if (_AliasLevel == 0)
1668 return alias_type(AliasIdxBot);
1669
1670 AliasCacheEntry* ace = probe_alias_cache(adr_type);
1671 if (ace->_adr_type == adr_type) {
1672 return alias_type(ace->_index);
1673 }
1674
1675 // Handle special cases.
1676 if (adr_type == NULL) return alias_type(AliasIdxTop);
1677 if (adr_type == TypePtr::BOTTOM) return alias_type(AliasIdxBot);
1678
1679 // Do it the slow way.
1680 const TypePtr* flat = flatten_alias_type(adr_type);
1681
1682 #ifdef ASSERT
1683 assert(flat == flatten_alias_type(flat), "idempotent");
1684 assert(flat != TypePtr::BOTTOM, "cannot alias-analyze an untyped ptr");
1685 if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1686 const TypeOopPtr* foop = flat->is_oopptr();
1687 // Scalarizable allocations have exact klass always.
1688 bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1689 const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1690 assert(foop == flatten_alias_type(xoop), "exactness must not affect alias type");
1691 }
1692 assert(flat == flatten_alias_type(flat), "exact bit doesn't matter");
1693 #endif
1694
1695 int idx = AliasIdxTop;
1696 for (int i = 0; i < num_alias_types(); i++) {
1697 if (alias_type(i)->adr_type() == flat) {
1698 idx = i;
1699 break;
1700 }
1701 }
1702
1703 if (idx == AliasIdxTop) {
1704 if (no_create) return NULL;
1705 // Grow the array if necessary.
1706 if (_num_alias_types == _max_alias_types) grow_alias_types();
1707 // Add a new alias type.
1708 idx = _num_alias_types++;
1709 _alias_types[idx]->Init(idx, flat);
1710 if (flat == TypeInstPtr::KLASS) alias_type(idx)->set_rewritable(false);
1711 if (flat == TypeAryPtr::RANGE) alias_type(idx)->set_rewritable(false);
1712 if (flat->isa_instptr()) {
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1663
1664
1665 //--------------------------------find_alias_type------------------------------
1666 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1667 if (_AliasLevel == 0)
1668 return alias_type(AliasIdxBot);
1669
1670 AliasCacheEntry* ace = probe_alias_cache(adr_type);
1671 if (ace->_adr_type == adr_type) {
1672 return alias_type(ace->_index);
1673 }
1674
1675 // Handle special cases.
1676 if (adr_type == NULL) return alias_type(AliasIdxTop);
1677 if (adr_type == TypePtr::BOTTOM) return alias_type(AliasIdxBot);
1678
1679 // Do it the slow way.
1680 const TypePtr* flat = flatten_alias_type(adr_type);
1681
1682 #ifdef ASSERT
1683 {
1684 ResourceMark rm;
1685 assert(flat == flatten_alias_type(flat),
1686 err_msg("not idempotent: adr_type = %s; flat = %s => %s", Type::str(adr_type),
1687 Type::str(flat), Type::str(flatten_alias_type(flat))));
1688 assert(flat != TypePtr::BOTTOM,
1689 err_msg("cannot alias-analyze an untyped ptr: adr_type = %s", Type::str(adr_type)));
1690 if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1691 const TypeOopPtr* foop = flat->is_oopptr();
1692 // Scalarizable allocations have exact klass always.
1693 bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1694 const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1695 assert(foop == flatten_alias_type(xoop),
1696 err_msg("exactness must not affect alias type: foop = %s; xoop = %s",
1697 Type::str(foop), Type::str(xoop)));
1698 }
1699 }
1700 #endif
1701
1702 int idx = AliasIdxTop;
1703 for (int i = 0; i < num_alias_types(); i++) {
1704 if (alias_type(i)->adr_type() == flat) {
1705 idx = i;
1706 break;
1707 }
1708 }
1709
1710 if (idx == AliasIdxTop) {
1711 if (no_create) return NULL;
1712 // Grow the array if necessary.
1713 if (_num_alias_types == _max_alias_types) grow_alias_types();
1714 // Add a new alias type.
1715 idx = _num_alias_types++;
1716 _alias_types[idx]->Init(idx, flat);
1717 if (flat == TypeInstPtr::KLASS) alias_type(idx)->set_rewritable(false);
1718 if (flat == TypeAryPtr::RANGE) alias_type(idx)->set_rewritable(false);
1719 if (flat->isa_instptr()) {
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