Mercurial > hg > truffle
changeset 12190:edb5ab0f3fe5
8001107: @Stable annotation for constant folding of lazily evaluated variables
Reviewed-by: rbackman, twisti, kvn
Contributed-by: john.r.rose@oracle.com, vladimir.x.ivanov@oracle.com
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--- a/src/share/vm/ci/ciArray.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/ci/ciArray.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -24,13 +24,92 @@ #include "precompiled.hpp" #include "ci/ciArray.hpp" +#include "ci/ciArrayKlass.hpp" +#include "ci/ciConstant.hpp" #include "ci/ciKlass.hpp" #include "ci/ciUtilities.hpp" +#include "oops/objArrayOop.hpp" +#include "oops/typeArrayOop.hpp" // ciArray // // This class represents an arrayOop in the HotSpot virtual // machine. +static BasicType fixup_element_type(BasicType bt) { + if (bt == T_ARRAY) return T_OBJECT; + if (bt == T_BOOLEAN) return T_BYTE; + return bt; +} + +ciConstant ciArray::element_value_impl(BasicType elembt, + arrayOop ary, + int index) { + if (ary == NULL) + return ciConstant(); + assert(ary->is_array(), ""); + if (index < 0 || index >= ary->length()) + return ciConstant(); + ArrayKlass* ak = (ArrayKlass*) ary->klass(); + BasicType abt = ak->element_type(); + if (fixup_element_type(elembt) != + fixup_element_type(abt)) + return ciConstant(); + switch (elembt) { + case T_ARRAY: + case T_OBJECT: + { + assert(ary->is_objArray(), ""); + objArrayOop objary = (objArrayOop) ary; + oop elem = objary->obj_at(index); + ciEnv* env = CURRENT_ENV; + ciObject* box = env->get_object(elem); + return ciConstant(T_OBJECT, box); + } + } + assert(ary->is_typeArray(), ""); + typeArrayOop tary = (typeArrayOop) ary; + jint value = 0; + switch (elembt) { + case T_LONG: return ciConstant(tary->long_at(index)); + case T_FLOAT: return ciConstant(tary->float_at(index)); + case T_DOUBLE: return ciConstant(tary->double_at(index)); + default: return ciConstant(); + case T_BYTE: value = tary->byte_at(index); break; + case T_BOOLEAN: value = tary->byte_at(index) & 1; break; + case T_SHORT: value = tary->short_at(index); break; + case T_CHAR: value = tary->char_at(index); break; + case T_INT: value = tary->int_at(index); break; + } + return ciConstant(elembt, value); +} + +// ------------------------------------------------------------------ +// ciArray::element_value +// +// Current value of an element. +// Returns T_ILLEGAL if there is no element at the given index. +ciConstant ciArray::element_value(int index) { + BasicType elembt = element_basic_type(); + GUARDED_VM_ENTRY( + return element_value_impl(elembt, get_arrayOop(), index); + ) +} + +// ------------------------------------------------------------------ +// ciArray::element_value_by_offset +// +// Current value of an element at the specified offset. +// Returns T_ILLEGAL if there is no element at the given offset. +ciConstant ciArray::element_value_by_offset(intptr_t element_offset) { + BasicType elembt = element_basic_type(); + intptr_t shift = exact_log2(type2aelembytes(elembt)); + intptr_t header = arrayOopDesc::base_offset_in_bytes(elembt); + intptr_t index = (element_offset - header) >> shift; + intptr_t offset = header + ((intptr_t)index << shift); + if (offset != element_offset || index != (jint)index) + return ciConstant(); + return element_value((jint) index); +} // ------------------------------------------------------------------ // ciArray::print_impl
--- a/src/share/vm/ci/ciArray.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/ci/ciArray.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -25,6 +25,8 @@ #ifndef SHARE_VM_CI_CIARRAY_HPP #define SHARE_VM_CI_CIARRAY_HPP +#include "ci/ciArrayKlass.hpp" +#include "ci/ciConstant.hpp" #include "ci/ciObject.hpp" #include "oops/arrayOop.hpp" #include "oops/objArrayOop.hpp" @@ -45,15 +47,30 @@ ciArray(ciKlass* klass, int len) : ciObject(klass), _length(len) {} - arrayOop get_arrayOop() { return (arrayOop)get_oop(); } + arrayOop get_arrayOop() const { return (arrayOop)get_oop(); } const char* type_string() { return "ciArray"; } void print_impl(outputStream* st); + ciConstant element_value_impl(BasicType elembt, arrayOop ary, int index); + public: int length() { return _length; } + // Convenience routines. + ciArrayKlass* array_type() { return klass()->as_array_klass(); } + ciType* element_type() { return array_type()->element_type(); } + BasicType element_basic_type() { return element_type()->basic_type(); } + + // Current value of an element. + // Returns T_ILLEGAL if there is no element at the given index. + ciConstant element_value(int index); + + // Current value of an element at the specified offset. + // Returns T_ILLEGAL if there is no element at the given offset. + ciConstant element_value_by_offset(intptr_t element_offset); + // What kind of ciObject is this? bool is_array() { return true; } bool is_java_object() { return true; }
--- a/src/share/vm/ci/ciConstant.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/ci/ciConstant.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -41,7 +41,6 @@ union { jint _int; jlong _long; - jint _long_half[2]; jfloat _float; jdouble _double; ciObject* _object; @@ -111,6 +110,20 @@ return _value._object; } + bool is_null_or_zero() const { + if (!is_java_primitive(basic_type())) { + return as_object()->is_null_object(); + } else if (type2size[basic_type()] == 1) { + // treat float bits as int, to avoid comparison with -0 and NaN + return (_value._int == 0); + } else if (type2size[basic_type()] == 2) { + // treat double bits as long, to avoid comparison with -0 and NaN + return (_value._long == 0); + } else { + return false; + } + } + // Debugging output void print(); };
--- a/src/share/vm/ci/ciField.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/ci/ciField.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -189,12 +189,14 @@ _holder = CURRENT_ENV->get_instance_klass(fd->field_holder()); // Check to see if the field is constant. - if (_holder->is_initialized() && this->is_final()) { + bool is_final = this->is_final(); + bool is_stable = FoldStableValues && this->is_stable(); + if (_holder->is_initialized() && (is_final || is_stable)) { if (!this->is_static()) { // A field can be constant if it's a final static field or if // it's a final non-static field of a trusted class (classes in // java.lang.invoke and sun.invoke packages and subpackages). - if (trust_final_non_static_fields(_holder)) { + if (is_stable || trust_final_non_static_fields(_holder)) { _is_constant = true; return; } @@ -227,7 +229,6 @@ Handle mirror = k->java_mirror(); - _is_constant = true; switch(type()->basic_type()) { case T_BYTE: _constant_value = ciConstant(type()->basic_type(), mirror->byte_field(_offset)); @@ -273,6 +274,12 @@ } } } + if (is_stable && _constant_value.is_null_or_zero()) { + // It is not a constant after all; treat it as uninitialized. + _is_constant = false; + } else { + _is_constant = true; + } } else { _is_constant = false; } @@ -373,8 +380,11 @@ tty->print(" signature="); _signature->print_symbol(); tty->print(" offset=%d type=", _offset); - if (_type != NULL) _type->print_name(); - else tty->print("(reference)"); + if (_type != NULL) + _type->print_name(); + else + tty->print("(reference)"); + tty->print(" flags=%04x", flags().as_int()); tty->print(" is_constant=%s", bool_to_str(_is_constant)); if (_is_constant && is_static()) { tty->print(" constant_value=");
--- a/src/share/vm/ci/ciField.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/ci/ciField.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -139,7 +139,10 @@ // non-constant fields. These are java.lang.System.in // and java.lang.System.out. Abomination. // - // Note: the check for case 4 is not yet implemented. + // A field is also considered constant if it is marked @Stable + // and is non-null (or non-zero, if a primitive). + // For non-static fields, the null/zero check must be + // arranged by the user, as constant_value().is_null_or_zero(). bool is_constant() { return _is_constant; } // Get the constant value of this field. @@ -173,6 +176,7 @@ bool is_protected () { return flags().is_protected(); } bool is_static () { return flags().is_static(); } bool is_final () { return flags().is_final(); } + bool is_stable () { return flags().is_stable(); } bool is_volatile () { return flags().is_volatile(); } bool is_transient () { return flags().is_transient(); }
--- a/src/share/vm/ci/ciFlags.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/ci/ciFlags.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -59,6 +59,7 @@ bool is_interface () const { return (_flags & JVM_ACC_INTERFACE ) != 0; } bool is_abstract () const { return (_flags & JVM_ACC_ABSTRACT ) != 0; } bool is_strict () const { return (_flags & JVM_ACC_STRICT ) != 0; } + bool is_stable () const { return (_flags & JVM_ACC_FIELD_STABLE) != 0; } // Conversion jint as_int() { return _flags; }
--- a/src/share/vm/ci/ciInstance.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/ci/ciInstance.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -127,6 +127,8 @@ ciConstant ciInstance::field_value_by_offset(int field_offset) { ciInstanceKlass* ik = klass()->as_instance_klass(); ciField* field = ik->get_field_by_offset(field_offset, false); + if (field == NULL) + return ciConstant(); // T_ILLEGAL return field_value(field); }
--- a/src/share/vm/ci/ciTypeArray.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/ci/ciTypeArray.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -39,5 +39,10 @@ jchar ciTypeArray::char_at(int index) { VM_ENTRY_MARK; assert(index >= 0 && index < length(), "out of range"); - return get_typeArrayOop()->char_at(index); + jchar c = get_typeArrayOop()->char_at(index); +#ifdef ASSERT + jchar d = element_value(index).as_char(); + assert(c == d, ""); +#endif //ASSERT + return c; }
--- a/src/share/vm/classfile/classFileParser.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/classfile/classFileParser.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -1774,6 +1774,10 @@ if (_location != _in_method) break; // only allow for methods if (!privileged) break; // only allow in privileged code return _method_LambdaForm_Hidden; + case vmSymbols::VM_SYMBOL_ENUM_NAME(sun_invoke_Stable_signature): + if (_location != _in_field) break; // only allow for fields + if (!privileged) break; // only allow in privileged code + return _field_Stable; case vmSymbols::VM_SYMBOL_ENUM_NAME(sun_misc_Contended_signature): if (_location != _in_field && _location != _in_class) break; // only allow for fields and classes if (!EnableContended || (RestrictContended && !privileged)) break; // honor privileges @@ -1786,6 +1790,8 @@ void ClassFileParser::FieldAnnotationCollector::apply_to(FieldInfo* f) { if (is_contended()) f->set_contended_group(contended_group()); + if (is_stable()) + f->set_stable(true); } ClassFileParser::FieldAnnotationCollector::~FieldAnnotationCollector() {
--- a/src/share/vm/classfile/classFileParser.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/classfile/classFileParser.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -125,6 +125,7 @@ _method_LambdaForm_Compiled, _method_LambdaForm_Hidden, _sun_misc_Contended, + _field_Stable, _annotation_LIMIT }; const Location _location; @@ -143,14 +144,23 @@ assert((int)id >= 0 && (int)id < (int)_annotation_LIMIT, "oob"); _annotations_present |= nth_bit((int)id); } + + void remove_annotation(ID id) { + assert((int)id >= 0 && (int)id < (int)_annotation_LIMIT, "oob"); + _annotations_present &= ~nth_bit((int)id); + } + // Report if the annotation is present. - bool has_any_annotations() { return _annotations_present != 0; } - bool has_annotation(ID id) { return (nth_bit((int)id) & _annotations_present) != 0; } + bool has_any_annotations() const { return _annotations_present != 0; } + bool has_annotation(ID id) const { return (nth_bit((int)id) & _annotations_present) != 0; } void set_contended_group(u2 group) { _contended_group = group; } - u2 contended_group() { return _contended_group; } + u2 contended_group() const { return _contended_group; } - bool is_contended() { return has_annotation(_sun_misc_Contended); } + bool is_contended() const { return has_annotation(_sun_misc_Contended); } + + void set_stable(bool stable) { set_annotation(_field_Stable); } + bool is_stable() const { return has_annotation(_field_Stable); } }; // This class also doubles as a holder for metadata cleanup.
--- a/src/share/vm/classfile/vmSymbols.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/classfile/vmSymbols.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -270,6 +270,7 @@ template(java_lang_invoke_LambdaForm, "java/lang/invoke/LambdaForm") \ template(java_lang_invoke_ForceInline_signature, "Ljava/lang/invoke/ForceInline;") \ template(java_lang_invoke_DontInline_signature, "Ljava/lang/invoke/DontInline;") \ + template(sun_invoke_Stable_signature, "Lsun/invoke/Stable;") \ template(java_lang_invoke_LambdaForm_Compiled_signature, "Ljava/lang/invoke/LambdaForm$Compiled;") \ template(java_lang_invoke_LambdaForm_Hidden_signature, "Ljava/lang/invoke/LambdaForm$Hidden;") \ template(java_lang_invoke_MagicLambdaImpl, "java/lang/invoke/MagicLambdaImpl") \
--- a/src/share/vm/oops/fieldInfo.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/oops/fieldInfo.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -240,6 +240,14 @@ return (access_flags() & JVM_ACC_FIELD_INTERNAL) != 0; } + bool is_stable() const { + return (access_flags() & JVM_ACC_FIELD_STABLE) != 0; + } + void set_stable(bool z) { + if (z) _shorts[access_flags_offset] |= JVM_ACC_FIELD_STABLE; + else _shorts[access_flags_offset] &= ~JVM_ACC_FIELD_STABLE; + } + Symbol* lookup_symbol(int symbol_index) const { assert(is_internal(), "only internal fields"); return vmSymbols::symbol_at((vmSymbols::SID)symbol_index);
--- a/src/share/vm/opto/c2_globals.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/c2_globals.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -448,6 +448,9 @@ product(bool, EliminateAutoBox, true, \ "Control optimizations for autobox elimination") \ \ + experimental(bool, UseImplicitStableValues, false, \ + "Mark well-known stable fields as such (e.g. String.value)") \ + \ product(intx, AutoBoxCacheMax, 128, \ "Sets max value cached by the java.lang.Integer autobox cache") \ \
--- a/src/share/vm/opto/compile.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/compile.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -1297,6 +1297,10 @@ // 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 @@ _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 @@ && 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 @@ 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; }
--- a/src/share/vm/opto/compile.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/compile.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -72,6 +72,7 @@ class StartNode; class SafePointNode; class JVMState; +class Type; class TypeData; class TypePtr; class TypeOopPtr; @@ -119,6 +120,7 @@ int _index; // unique index, used with MergeMemNode const TypePtr* _adr_type; // normalized address type ciField* _field; // relevant instance field, or null if none + const Type* _element; // relevant array element type, or null if none bool _is_rewritable; // false if the memory is write-once only int _general_index; // if this is type is an instance, the general // type that this is an instance of @@ -129,6 +131,7 @@ int index() const { return _index; } const TypePtr* adr_type() const { return _adr_type; } ciField* field() const { return _field; } + const Type* element() const { return _element; } bool is_rewritable() const { return _is_rewritable; } bool is_volatile() const { return (_field ? _field->is_volatile() : false); } int general_index() const { return (_general_index != 0) ? _general_index : _index; } @@ -137,7 +140,14 @@ void set_field(ciField* f) { assert(!_field,""); _field = f; - if (f->is_final()) _is_rewritable = false; + if (f->is_final() || f->is_stable()) { + // In the case of @Stable, multiple writes are possible but may be assumed to be no-ops. + _is_rewritable = false; + } + } + void set_element(const Type* e) { + assert(_element == NULL, ""); + _element = e; } void print_on(outputStream* st) PRODUCT_RETURN;
--- a/src/share/vm/opto/graphKit.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/graphKit.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -3825,8 +3825,13 @@ TypeAry::make(TypeInt::CHAR,TypeInt::POS), ciTypeArrayKlass::make(T_CHAR), true, 0); int value_field_idx = C->get_alias_index(value_field_type); - return make_load(ctrl, basic_plus_adr(str, str, value_offset), - value_type, T_OBJECT, value_field_idx); + Node* load = make_load(ctrl, basic_plus_adr(str, str, value_offset), + value_type, T_OBJECT, value_field_idx); + // String.value field is known to be @Stable. + if (UseImplicitStableValues) { + load = cast_array_to_stable(load, value_type); + } + return load; } void GraphKit::store_String_offset(Node* ctrl, Node* str, Node* value) { @@ -3844,9 +3849,6 @@ const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(), false, NULL, 0); const TypePtr* value_field_type = string_type->add_offset(value_offset); - const TypeAryPtr* value_type = TypeAryPtr::make(TypePtr::NotNull, - TypeAry::make(TypeInt::CHAR,TypeInt::POS), - ciTypeArrayKlass::make(T_CHAR), true, 0); int value_field_idx = C->get_alias_index(value_field_type); store_to_memory(ctrl, basic_plus_adr(str, value_offset), value, T_OBJECT, value_field_idx); @@ -3861,3 +3863,9 @@ store_to_memory(ctrl, basic_plus_adr(str, count_offset), value, T_INT, count_field_idx); } + +Node* GraphKit::cast_array_to_stable(Node* ary, const TypeAryPtr* ary_type) { + // Reify the property as a CastPP node in Ideal graph to comply with monotonicity + // assumption of CCP analysis. + return _gvn.transform(new(C) CastPPNode(ary, ary_type->cast_to_stable(true))); +}
--- a/src/share/vm/opto/graphKit.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/graphKit.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -836,6 +836,9 @@ // Insert a loop predicate into the graph void add_predicate(int nargs = 0); void add_predicate_impl(Deoptimization::DeoptReason reason, int nargs); + + // Produce new array node of stable type + Node* cast_array_to_stable(Node* ary, const TypeAryPtr* ary_type); }; // Helper class to support building of control flow branches. Upon
--- a/src/share/vm/opto/library_call.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/library_call.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -1280,6 +1280,11 @@ const TypeAry* target_array_type = TypeAry::make(TypeInt::CHAR, TypeInt::make(0, target_length, Type::WidenMin)); const TypeAryPtr* target_type = TypeAryPtr::make(TypePtr::BotPTR, target_array_type, target_array->klass(), true, Type::OffsetBot); + // String.value field is known to be @Stable. + if (UseImplicitStableValues) { + target = cast_array_to_stable(target, target_type); + } + IdealKit kit(this, false, true); #define __ kit. Node* zero = __ ConI(0);
--- a/src/share/vm/opto/memnode.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/memnode.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -962,6 +962,19 @@ return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address); } +static bool skip_through_membars(Compile::AliasType* atp, const TypeInstPtr* tp, bool eliminate_boxing) { + if ((atp != NULL) && (atp->index() >= Compile::AliasIdxRaw)) { + bool non_volatile = (atp->field() != NULL) && !atp->field()->is_volatile(); + bool is_stable_ary = FoldStableValues && + (tp != NULL) && (tp->isa_aryptr() != NULL) && + tp->isa_aryptr()->is_stable(); + + return (eliminate_boxing && non_volatile) || is_stable_ary; + } + + return false; +} + //---------------------------can_see_stored_value------------------------------ // This routine exists to make sure this set of tests is done the same // everywhere. We need to make a coordinated change: first LoadNode::Ideal @@ -976,11 +989,9 @@ const TypeInstPtr* tp = phase->type(ld_adr)->isa_instptr(); Compile::AliasType* atp = (tp != NULL) ? phase->C->alias_type(tp) : NULL; // This is more general than load from boxing objects. - if (phase->C->eliminate_boxing() && (atp != NULL) && - (atp->index() >= Compile::AliasIdxRaw) && - (atp->field() != NULL) && !atp->field()->is_volatile()) { + if (skip_through_membars(atp, tp, phase->C->eliminate_boxing())) { uint alias_idx = atp->index(); - bool final = atp->field()->is_final(); + bool final = !atp->is_rewritable(); Node* result = NULL; Node* current = st; // Skip through chains of MemBarNodes checking the MergeMems for @@ -1015,7 +1026,6 @@ } } - // Loop around twice in the case Load -> Initialize -> Store. // (See PhaseIterGVN::add_users_to_worklist, which knows about this case.) for (int trip = 0; trip <= 1; trip++) { @@ -1577,6 +1587,40 @@ return NULL; } +// Try to constant-fold a stable array element. +static const Type* fold_stable_ary_elem(const TypeAryPtr* ary, int off, BasicType loadbt) { + assert(ary->is_stable(), "array should be stable"); + + if (ary->const_oop() != NULL) { + // Decode the results of GraphKit::array_element_address. + ciArray* aobj = ary->const_oop()->as_array(); + ciConstant con = aobj->element_value_by_offset(off); + + if (con.basic_type() != T_ILLEGAL && !con.is_null_or_zero()) { + const Type* con_type = Type::make_from_constant(con); + if (con_type != NULL) { + if (con_type->isa_aryptr()) { + // Join with the array element type, in case it is also stable. + int dim = ary->stable_dimension(); + con_type = con_type->is_aryptr()->cast_to_stable(true, dim-1); + } + if (loadbt == T_NARROWOOP && con_type->isa_oopptr()) { + con_type = con_type->make_narrowoop(); + } +#ifndef PRODUCT + if (TraceIterativeGVN) { + tty->print("FoldStableValues: array element [off=%d]: con_type=", off); + con_type->dump(); tty->cr(); + } +#endif //PRODUCT + return con_type; + } + } + } + + return NULL; +} + //------------------------------Value----------------------------------------- const Type *LoadNode::Value( PhaseTransform *phase ) const { // Either input is TOP ==> the result is TOP @@ -1591,8 +1635,31 @@ Compile* C = phase->C; // Try to guess loaded type from pointer type - if (tp->base() == Type::AryPtr) { - const Type *t = tp->is_aryptr()->elem(); + if (tp->isa_aryptr()) { + const TypeAryPtr* ary = tp->is_aryptr(); + const Type *t = ary->elem(); + + // Determine whether the reference is beyond the header or not, by comparing + // the offset against the offset of the start of the array's data. + // Different array types begin at slightly different offsets (12 vs. 16). + // We choose T_BYTE as an example base type that is least restrictive + // as to alignment, which will therefore produce the smallest + // possible base offset. + const int min_base_off = arrayOopDesc::base_offset_in_bytes(T_BYTE); + const bool off_beyond_header = ((uint)off >= (uint)min_base_off); + + // Try to constant-fold a stable array element. + if (FoldStableValues && ary->is_stable()) { + // Make sure the reference is not into the header + if (off_beyond_header && off != Type::OffsetBot) { + assert(adr->is_AddP() && adr->in(AddPNode::Offset)->is_Con(), "offset is a constant"); + const Type* con_type = fold_stable_ary_elem(ary, off, memory_type()); + if (con_type != NULL) { + return con_type; + } + } + } + // Don't do this for integer types. There is only potential profit if // the element type t is lower than _type; that is, for int types, if _type is // more restrictive than t. This only happens here if one is short and the other @@ -1613,14 +1680,7 @@ && Opcode() != Op_LoadKlass && Opcode() != Op_LoadNKlass) { // t might actually be lower than _type, if _type is a unique // concrete subclass of abstract class t. - // Make sure the reference is not into the header, by comparing - // the offset against the offset of the start of the array's data. - // Different array types begin at slightly different offsets (12 vs. 16). - // We choose T_BYTE as an example base type that is least restrictive - // as to alignment, which will therefore produce the smallest - // possible base offset. - const int min_base_off = arrayOopDesc::base_offset_in_bytes(T_BYTE); - if ((uint)off >= (uint)min_base_off) { // is the offset beyond the header? + if (off_beyond_header) { // is the offset beyond the header? const Type* jt = t->join(_type); // In any case, do not allow the join, per se, to empty out the type. if (jt->empty() && !t->empty()) {
--- a/src/share/vm/opto/parse.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/parse.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -518,7 +518,7 @@ // loading from a constant field or the constant pool // returns false if push failed (non-perm field constants only, not ldcs) - bool push_constant(ciConstant con, bool require_constant = false, bool is_autobox_cache = false); + bool push_constant(ciConstant con, bool require_constant = false, bool is_autobox_cache = false, const Type* basic_type = NULL); // implementation of object creation bytecodes void emit_guard_for_new(ciInstanceKlass* klass);
--- a/src/share/vm/opto/parse3.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/parse3.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -147,7 +147,15 @@ void Parse::do_get_xxx(Node* obj, ciField* field, bool is_field) { // Does this field have a constant value? If so, just push the value. if (field->is_constant()) { - // final field + // final or stable field + const Type* stable_type = NULL; + if (FoldStableValues && field->is_stable()) { + stable_type = Type::get_const_type(field->type()); + if (field->type()->is_array_klass()) { + int stable_dimension = field->type()->as_array_klass()->dimension(); + stable_type = stable_type->is_aryptr()->cast_to_stable(true, stable_dimension); + } + } if (field->is_static()) { // final static field if (C->eliminate_boxing()) { @@ -167,11 +175,10 @@ } } } - if (push_constant(field->constant_value())) + if (push_constant(field->constant_value(), false, false, stable_type)) return; - } - else { - // final non-static field + } else { + // final or stable non-static field // Treat final non-static fields of trusted classes (classes in // java.lang.invoke and sun.invoke packages and subpackages) as // compile time constants. @@ -179,8 +186,12 @@ const TypeOopPtr* oop_ptr = obj->bottom_type()->isa_oopptr(); ciObject* constant_oop = oop_ptr->const_oop(); ciConstant constant = field->constant_value_of(constant_oop); - if (push_constant(constant, true)) - return; + if (FoldStableValues && field->is_stable() && constant.is_null_or_zero()) { + // fall through to field load; the field is not yet initialized + } else { + if (push_constant(constant, true, false, stable_type)) + return; + } } } } @@ -301,7 +312,8 @@ // Note the presence of writes to final non-static fields, so that we // can insert a memory barrier later on to keep the writes from floating // out of the constructor. - if (is_field && field->is_final()) { + // Any method can write a @Stable field; insert memory barriers after those also. + if (is_field && (field->is_final() || field->is_stable())) { set_wrote_final(true); // Preserve allocation ptr to create precedent edge to it in membar // generated on exit from constructor. @@ -314,35 +326,21 @@ } -bool Parse::push_constant(ciConstant constant, bool require_constant, bool is_autobox_cache) { + +bool Parse::push_constant(ciConstant constant, bool require_constant, bool is_autobox_cache, const Type* stable_type) { + const Type* con_type = Type::make_from_constant(constant, require_constant, is_autobox_cache); switch (constant.basic_type()) { - case T_BOOLEAN: push( intcon(constant.as_boolean()) ); break; - case T_INT: push( intcon(constant.as_int()) ); break; - case T_CHAR: push( intcon(constant.as_char()) ); break; - case T_BYTE: push( intcon(constant.as_byte()) ); break; - case T_SHORT: push( intcon(constant.as_short()) ); break; - case T_FLOAT: push( makecon(TypeF::make(constant.as_float())) ); break; - case T_DOUBLE: push_pair( makecon(TypeD::make(constant.as_double())) ); break; - case T_LONG: push_pair( longcon(constant.as_long()) ); break; case T_ARRAY: - case T_OBJECT: { + case T_OBJECT: // cases: // can_be_constant = (oop not scavengable || ScavengeRootsInCode != 0) // should_be_constant = (oop not scavengable || ScavengeRootsInCode >= 2) // An oop is not scavengable if it is in the perm gen. - ciObject* oop_constant = constant.as_object(); - if (oop_constant->is_null_object()) { - push( zerocon(T_OBJECT) ); - break; - } else if (require_constant || oop_constant->should_be_constant()) { - push( makecon(TypeOopPtr::make_from_constant(oop_constant, require_constant, is_autobox_cache)) ); - break; - } else { - // we cannot inline the oop, but we can use it later to narrow a type - return false; - } - } - case T_ILLEGAL: { + if (stable_type != NULL && con_type != NULL && con_type->isa_oopptr()) + con_type = con_type->join(stable_type); + break; + + case T_ILLEGAL: // Invalid ciConstant returned due to OutOfMemoryError in the CI assert(C->env()->failing(), "otherwise should not see this"); // These always occur because of object types; we are going to @@ -350,17 +348,16 @@ push( zerocon(T_OBJECT) ); return false; } - default: - ShouldNotReachHere(); + + if (con_type == NULL) + // we cannot inline the oop, but we can use it later to narrow a type return false; - } - // success + push_node(constant.basic_type(), makecon(con_type)); return true; } - //============================================================================= void Parse::do_anewarray() { bool will_link;
--- a/src/share/vm/opto/type.cpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/type.cpp Tue Sep 10 14:51:48 2013 -0700 @@ -189,6 +189,38 @@ } +//-----------------------make_from_constant------------------------------------ +const Type* Type::make_from_constant(ciConstant constant, + bool require_constant, bool is_autobox_cache) { + switch (constant.basic_type()) { + case T_BOOLEAN: return TypeInt::make(constant.as_boolean()); + case T_CHAR: return TypeInt::make(constant.as_char()); + case T_BYTE: return TypeInt::make(constant.as_byte()); + case T_SHORT: return TypeInt::make(constant.as_short()); + case T_INT: return TypeInt::make(constant.as_int()); + case T_LONG: return TypeLong::make(constant.as_long()); + case T_FLOAT: return TypeF::make(constant.as_float()); + case T_DOUBLE: return TypeD::make(constant.as_double()); + case T_ARRAY: + case T_OBJECT: + { + // cases: + // can_be_constant = (oop not scavengable || ScavengeRootsInCode != 0) + // should_be_constant = (oop not scavengable || ScavengeRootsInCode >= 2) + // An oop is not scavengable if it is in the perm gen. + ciObject* oop_constant = constant.as_object(); + if (oop_constant->is_null_object()) { + return Type::get_zero_type(T_OBJECT); + } else if (require_constant || oop_constant->should_be_constant()) { + return TypeOopPtr::make_from_constant(oop_constant, require_constant, is_autobox_cache); + } + } + } + // Fall through to failure + return NULL; +} + + //------------------------------make------------------------------------------- // Create a simple Type, with default empty symbol sets. Then hashcons it // and look for an existing copy in the type dictionary. @@ -1824,12 +1856,12 @@ } //------------------------------make------------------------------------------- -const TypeAry *TypeAry::make( const Type *elem, const TypeInt *size) { +const TypeAry* TypeAry::make(const Type* elem, const TypeInt* size, bool stable) { if (UseCompressedOops && elem->isa_oopptr()) { elem = elem->make_narrowoop(); } size = normalize_array_size(size); - return (TypeAry*)(new TypeAry(elem,size))->hashcons(); + return (TypeAry*)(new TypeAry(elem,size,stable))->hashcons(); } //------------------------------meet------------------------------------------- @@ -1850,7 +1882,8 @@ case Array: { // Meeting 2 arrays? const TypeAry *a = t->is_ary(); return TypeAry::make(_elem->meet(a->_elem), - _size->xmeet(a->_size)->is_int()); + _size->xmeet(a->_size)->is_int(), + _stable & a->_stable); } case Top: break; @@ -1863,7 +1896,7 @@ const Type *TypeAry::xdual() const { const TypeInt* size_dual = _size->dual()->is_int(); size_dual = normalize_array_size(size_dual); - return new TypeAry( _elem->dual(), size_dual); + return new TypeAry(_elem->dual(), size_dual, !_stable); } //------------------------------eq--------------------------------------------- @@ -1871,13 +1904,14 @@ bool TypeAry::eq( const Type *t ) const { const TypeAry *a = (const TypeAry*)t; return _elem == a->_elem && + _stable == a->_stable && _size == a->_size; } //------------------------------hash------------------------------------------- // Type-specific hashing function. int TypeAry::hash(void) const { - return (intptr_t)_elem + (intptr_t)_size; + return (intptr_t)_elem + (intptr_t)_size + (_stable ? 43 : 0); } //----------------------interface_vs_oop--------------------------------------- @@ -1894,6 +1928,7 @@ //------------------------------dump2------------------------------------------ #ifndef PRODUCT void TypeAry::dump2( Dict &d, uint depth, outputStream *st ) const { + if (_stable) st->print("stable:"); _elem->dump2(d, depth, st); st->print("["); _size->dump2(d, depth, st); @@ -3457,11 +3492,39 @@ assert(new_size != NULL, ""); new_size = narrow_size_type(new_size); if (new_size == size()) return this; - const TypeAry* new_ary = TypeAry::make(elem(), new_size); + const TypeAry* new_ary = TypeAry::make(elem(), new_size, is_stable()); return make(ptr(), const_oop(), new_ary, klass(), klass_is_exact(), _offset, _instance_id); } +//------------------------------cast_to_stable--------------------------------- +const TypeAryPtr* TypeAryPtr::cast_to_stable(bool stable, int stable_dimension) const { + if (stable_dimension <= 0 || (stable_dimension == 1 && stable == this->is_stable())) + return this; + + const Type* elem = this->elem(); + const TypePtr* elem_ptr = elem->make_ptr(); + + if (stable_dimension > 1 && elem_ptr != NULL && elem_ptr->isa_aryptr()) { + // If this is widened from a narrow oop, TypeAry::make will re-narrow it. + elem = elem_ptr = elem_ptr->is_aryptr()->cast_to_stable(stable, stable_dimension - 1); + } + + const TypeAry* new_ary = TypeAry::make(elem, size(), stable); + + return make(ptr(), const_oop(), new_ary, klass(), klass_is_exact(), _offset, _instance_id); +} + +//-----------------------------stable_dimension-------------------------------- +int TypeAryPtr::stable_dimension() const { + if (!is_stable()) return 0; + int dim = 1; + const TypePtr* elem_ptr = elem()->make_ptr(); + if (elem_ptr != NULL && elem_ptr->isa_aryptr()) + dim += elem_ptr->is_aryptr()->stable_dimension(); + return dim; +} + //------------------------------eq--------------------------------------------- // Structural equality check for Type representations bool TypeAryPtr::eq( const Type *t ) const { @@ -3570,7 +3633,7 @@ // Something like byte[int+] meets char[int+]. // This must fall to bottom, not (int[-128..65535])[int+]. instance_id = InstanceBot; - tary = TypeAry::make(Type::BOTTOM, tary->_size); + tary = TypeAry::make(Type::BOTTOM, tary->_size, tary->_stable); } } else // Non integral arrays. // Must fall to bottom if exact klasses in upper lattice @@ -3584,7 +3647,7 @@ (tap ->_klass_is_exact && !tap->klass()->is_subtype_of(klass())) || // 'this' is exact and super or unrelated: (this->_klass_is_exact && !klass()->is_subtype_of(tap->klass())))) { - tary = TypeAry::make(Type::BOTTOM, tary->_size); + tary = TypeAry::make(Type::BOTTOM, tary->_size, tary->_stable); return make( NotNull, NULL, tary, lazy_klass, false, off, InstanceBot ); }
--- a/src/share/vm/opto/type.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/opto/type.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -372,6 +372,10 @@ // Mapping from CI type system to compiler type: static const Type* get_typeflow_type(ciType* type); + static const Type* make_from_constant(ciConstant constant, + bool require_constant = false, + bool is_autobox_cache = false); + private: // support arrays static const BasicType _basic_type[]; @@ -588,8 +592,8 @@ //------------------------------TypeAry---------------------------------------- // Class of Array Types class TypeAry : public Type { - TypeAry( const Type *elem, const TypeInt *size) : Type(Array), - _elem(elem), _size(size) {} + TypeAry(const Type* elem, const TypeInt* size, bool stable) : Type(Array), + _elem(elem), _size(size), _stable(stable) {} public: virtual bool eq( const Type *t ) const; virtual int hash() const; // Type specific hashing @@ -599,10 +603,11 @@ private: const Type *_elem; // Element type of array const TypeInt *_size; // Elements in array + const bool _stable; // Are elements @Stable? friend class TypeAryPtr; public: - static const TypeAry *make( const Type *elem, const TypeInt *size); + static const TypeAry* make(const Type* elem, const TypeInt* size, bool stable = false); virtual const Type *xmeet( const Type *t ) const; virtual const Type *xdual() const; // Compute dual right now. @@ -988,6 +993,7 @@ const TypeAry* ary() const { return _ary; } const Type* elem() const { return _ary->_elem; } const TypeInt* size() const { return _ary->_size; } + bool is_stable() const { return _ary->_stable; } bool is_autobox_cache() const { return _is_autobox_cache; } @@ -1011,6 +1017,9 @@ virtual const Type *xmeet( const Type *t ) const; virtual const Type *xdual() const; // Compute dual right now. + const TypeAryPtr* cast_to_stable(bool stable, int stable_dimension = 1) const; + int stable_dimension() const; + // Convenience common pre-built types. static const TypeAryPtr *RANGE; static const TypeAryPtr *OOPS;
--- a/src/share/vm/runtime/globals.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/runtime/globals.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -3649,6 +3649,9 @@ experimental(bool, TrustFinalNonStaticFields, false, \ "trust final non-static declarations for constant folding") \ \ + experimental(bool, FoldStableValues, false, \ + "Private flag to control optimizations for stable variables") \ + \ develop(bool, TraceInvokeDynamic, false, \ "trace internal invoke dynamic operations") \ \
--- a/src/share/vm/utilities/accessFlags.hpp Mon Sep 09 19:53:28 2013 +0200 +++ b/src/share/vm/utilities/accessFlags.hpp Tue Sep 10 14:51:48 2013 -0700 @@ -78,11 +78,13 @@ JVM_ACC_FIELD_ACCESS_WATCHED = 0x00002000, // field access is watched by JVMTI JVM_ACC_FIELD_MODIFICATION_WATCHED = 0x00008000, // field modification is watched by JVMTI JVM_ACC_FIELD_INTERNAL = 0x00000400, // internal field, same as JVM_ACC_ABSTRACT + JVM_ACC_FIELD_STABLE = 0x00000020, // @Stable field, same as JVM_ACC_SYNCHRONIZED JVM_ACC_FIELD_HAS_GENERIC_SIGNATURE = 0x00000800, // field has generic signature JVM_ACC_FIELD_INTERNAL_FLAGS = JVM_ACC_FIELD_ACCESS_WATCHED | JVM_ACC_FIELD_MODIFICATION_WATCHED | JVM_ACC_FIELD_INTERNAL | + JVM_ACC_FIELD_STABLE | JVM_ACC_FIELD_HAS_GENERIC_SIGNATURE, // flags accepted by set_field_flags() @@ -148,6 +150,7 @@ { return (_flags & JVM_ACC_FIELD_MODIFICATION_WATCHED) != 0; } bool on_stack() const { return (_flags & JVM_ACC_ON_STACK) != 0; } bool is_internal() const { return (_flags & JVM_ACC_FIELD_INTERNAL) != 0; } + bool is_stable() const { return (_flags & JVM_ACC_FIELD_STABLE) != 0; } bool field_has_generic_signature() const { return (_flags & JVM_ACC_FIELD_HAS_GENERIC_SIGNATURE) != 0; }