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8001107: @Stable annotation for constant folding of lazily evaluated variables

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Co-authored-by: John Rose <john.r.rose@oracle.com>
Reviewed-by: rbackman, twisti, kvn
This commit is contained in:
Vladimir Ivanov 2013-09-10 14:51:48 -07:00
parent 19d50345e1
commit f0e77ac67f
25 changed files with 419 additions and 84 deletions
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17
hotspot/src/share/vm/opto/compile.cpp
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@ -1297,6 +1297,10 @@ const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
// Array pointers need some flattening
const TypeAryPtr *ta = tj->isa_aryptr();
if (ta && ta->is_stable()) {
// Erase stability property for alias analysis.
tj = ta = ta->cast_to_stable(false);
}
if( ta && is_known_inst ) {
if ( offset != Type::OffsetBot &&
offset > arrayOopDesc::length_offset_in_bytes() ) {
@ -1497,6 +1501,7 @@ void Compile::AliasType::Init(int i, const TypePtr* at) {
_index = i;
_adr_type = at;
_field = NULL;
_element = NULL;
_is_rewritable = true; // default
const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
if (atoop != NULL && atoop->is_known_instance()) {
@ -1615,6 +1620,16 @@ Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_cr
&& flat->is_instptr()->klass() == env()->Class_klass())
alias_type(idx)->set_rewritable(false);
}
if (flat->isa_aryptr()) {
#ifdef ASSERT
const int header_size_min = arrayOopDesc::base_offset_in_bytes(T_BYTE);
// (T_BYTE has the weakest alignment and size restrictions...)
assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
#endif
if (flat->offset() == TypePtr::OffsetBot) {
alias_type(idx)->set_element(flat->is_aryptr()->elem());
}
}
if (flat->isa_klassptr()) {
if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
alias_type(idx)->set_rewritable(false);
@ -1677,7 +1692,7 @@ Compile::AliasType* Compile::alias_type(ciField* field) {
else
t = TypeOopPtr::make_from_klass_raw(field->holder());
AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
assert(field->is_final() == !atp->is_rewritable(), "must get the rewritable bits correct");
assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
return atp;
}