jdk8-mips64-public/hotspot: comparison src/share/vm/ci/ciField.cpp

--1:000000000000
+:f90c822e73f8
+/*
+* Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*
+*/
+#include "precompiled.hpp"
+#include "ci/ciField.hpp"
+#include "ci/ciInstanceKlass.hpp"
+#include "ci/ciUtilities.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "gc_interface/collectedHeap.inline.hpp"
+#include "interpreter/linkResolver.hpp"
+#include "memory/universe.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "oops/oop.inline2.hpp"
+#include "runtime/fieldDescriptor.hpp"
+// ciField
+//
+// This class represents the result of a field lookup in the VM.
+// The lookup may not succeed, in which case the information in
+// the ciField will be incomplete.
+// The ciObjectFactory cannot create circular data structures in one query.
+// To avoid vicious circularities, we initialize ciField::_type to NULL
+// for reference types and derive it lazily from the ciField::_signature.
+// Primitive types are eagerly initialized, and basic layout queries
+// can succeed without initialization, using only the BasicType of the field.
+// Notes on bootstrapping and shared CI objects:  A field is shared if and
+// only if it is (a) non-static and (b) declared by a shared instance klass.
+// This allows non-static field lists to be cached on shared types.
+// Because the _type field is lazily initialized, however, there is a
+// special restriction that a shared field cannot cache an unshared type.
+// This puts a small performance penalty on shared fields with unshared
+// types, such as StackTraceElement[] Throwable.stackTrace.
+// (Throwable is shared because ClassCastException is shared, but
+// StackTraceElement is not presently shared.)
+// It is not a vicious circularity for a ciField to recursively create
+// the ciSymbols necessary to represent its name and signature.
+// Therefore, these items are created eagerly, and the name and signature
+// of a shared field are themselves shared symbols.  This somewhat
+// pollutes the set of shared CI objects:  It grows from 50 to 93 items,
+// with all of the additional 43 being uninteresting shared ciSymbols.
+// This adds at most one step to the binary search, an amount which
+// decreases for complex compilation tasks.
+// ------------------------------------------------------------------
+// ciField::ciField
+ciField::ciField(ciInstanceKlass* klass, int index): _known_to_link_with_put(NULL), _known_to_link_with_get(NULL) {
+ASSERT_IN_VM;
+CompilerThread *thread = CompilerThread::current();
+assert(ciObjectFactory::is_initialized(), "not a shared field");
+assert(klass->get_instanceKlass()->is_linked(), "must be linked before using its constan-pool");
+constantPoolHandle cpool(thread, klass->get_instanceKlass()->constants());
+// Get the field's name, signature, and type.
+Symbol* name  = cpool->name_ref_at(index);
+_name = ciEnv::current(thread)->get_symbol(name);
+int nt_index = cpool->name_and_type_ref_index_at(index);
+int sig_index = cpool->signature_ref_index_at(nt_index);
+Symbol* signature = cpool->symbol_at(sig_index);
+_signature = ciEnv::current(thread)->get_symbol(signature);
+BasicType field_type = FieldType::basic_type(signature);
+// If the field is a pointer type, get the klass of the
+// field.
+if (field_type == T_OBJECT || field_type == T_ARRAY) {
+bool ignore;
+// This is not really a class reference; the index always refers to the
+// field's type signature, as a symbol.  Linkage checks do not apply.
+_type = ciEnv::current(thread)->get_klass_by_index(cpool, sig_index, ignore, klass);
+} else {
+_type = ciType::make(field_type);
+}
+_name = (ciSymbol*)ciEnv::current(thread)->get_symbol(name);
+// Get the field's declared holder.
+//
+// Note: we actually create a ciInstanceKlass for this klass,
+// even though we may not need to.
+int holder_index = cpool->klass_ref_index_at(index);
+bool holder_is_accessible;
+ciInstanceKlass* declared_holder =
+ciEnv::current(thread)->get_klass_by_index(cpool, holder_index,
+holder_is_accessible,
+klass)->as_instance_klass();
+// The declared holder of this field may not have been loaded.
+// Bail out with partial field information.
+if (!holder_is_accessible) {
+// _type has already been set.
+// The default values for _flags and _constant_value will suffice.
+// We need values for _holder, _offset,  and _is_constant,
+_holder = declared_holder;
+_offset = -1;
+_is_constant = false;
+return;
+}
+InstanceKlass* loaded_decl_holder = declared_holder->get_instanceKlass();
+// Perform the field lookup.
+fieldDescriptor field_desc;
+Klass* canonical_holder =
+loaded_decl_holder->find_field(name, signature, &field_desc);
+if (canonical_holder == NULL) {
+// Field lookup failed.  Will be detected by will_link.
+_holder = declared_holder;
+_offset = -1;
+_is_constant = false;
+return;
+}
+// Access check based on declared_holder. canonical_holder should not be used
+// to check access because it can erroneously succeed. If this check fails,
+// propagate the declared holder to will_link() which in turn will bail out
+// compilation for this field access.
+if (!Reflection::verify_field_access(klass->get_Klass(), declared_holder->get_Klass(), canonical_holder, field_desc.access_flags(), true)) {
+_holder = declared_holder;
+_offset = -1;
+_is_constant = false;
+return;
+}
+assert(canonical_holder == field_desc.field_holder(), "just checking");
+initialize_from(&field_desc);
+}
+ciField::ciField(fieldDescriptor *fd): _known_to_link_with_put(NULL), _known_to_link_with_get(NULL) {
+ASSERT_IN_VM;
+// Get the field's name, signature, and type.
+ciEnv* env = CURRENT_ENV;
+_name = env->get_symbol(fd->name());
+_signature = env->get_symbol(fd->signature());
+BasicType field_type = fd->field_type();
+// If the field is a pointer type, get the klass of the
+// field.
+if (field_type == T_OBJECT || field_type == T_ARRAY) {
+_type = NULL;  // must call compute_type on first access
+} else {
+_type = ciType::make(field_type);
+}
+initialize_from(fd);
+// Either (a) it is marked shared, or else (b) we are done bootstrapping.
+assert(is_shared() || ciObjectFactory::is_initialized(),
+"bootstrap classes must not create & cache unshared fields");
+}
+static bool trust_final_non_static_fields(ciInstanceKlass* holder) {
+if (holder == NULL)
+return false;
+if (holder->name() == ciSymbol::java_lang_System())
+// Never trust strangely unstable finals:  System.out, etc.
+return false;
+// Even if general trusting is disabled, trust system-built closures in these packages.
+if (holder->is_in_package("java/lang/invoke") || holder->is_in_package("sun/invoke"))
+return true;
+return TrustFinalNonStaticFields;
+}
+void ciField::initialize_from(fieldDescriptor* fd) {
+// Get the flags, offset, and canonical holder of the field.
+_flags = ciFlags(fd->access_flags());
+_offset = fd->offset();
+_holder = CURRENT_ENV->get_instance_klass(fd->field_holder());
+// Check to see if the field is constant.
+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 (is_stable || trust_final_non_static_fields(_holder)) {
+_is_constant = true;
+return;
+}
+_is_constant = false;
+return;
+}
+// This field just may be constant.  The only cases where it will
+// not be constant are:
+//
+// 1. The field holds a non-perm-space oop.  The field is, strictly
+//    speaking, constant but we cannot embed non-perm-space oops into
+//    generated code.  For the time being we need to consider the
+//    field to be not constant.
+// 2. The field is a *special* static&final field whose value
+//    may change.  The three examples are java.lang.System.in,
+//    java.lang.System.out, and java.lang.System.err.
+KlassHandle k = _holder->get_Klass();
+assert( SystemDictionary::System_klass() != NULL, "Check once per vm");
+if( k() == SystemDictionary::System_klass() ) {
+// Check offsets for case 2: System.in, System.out, or System.err
+if( _offset == java_lang_System::in_offset_in_bytes()  ||
+_offset == java_lang_System::out_offset_in_bytes() ||
+_offset == java_lang_System::err_offset_in_bytes() ) {
+_is_constant = false;
+return;
+}
+}
+Handle mirror = k->java_mirror();
+switch(type()->basic_type()) {
+case T_BYTE:
+_constant_value = ciConstant(type()->basic_type(), mirror->byte_field(_offset));
+break;
+case T_CHAR:
+_constant_value = ciConstant(type()->basic_type(), mirror->char_field(_offset));
+break;
+case T_SHORT:
+_constant_value = ciConstant(type()->basic_type(), mirror->short_field(_offset));
+break;
+case T_BOOLEAN:
+_constant_value = ciConstant(type()->basic_type(), mirror->bool_field(_offset));
+break;
+case T_INT:
+_constant_value = ciConstant(type()->basic_type(), mirror->int_field(_offset));
+break;
+case T_FLOAT:
+_constant_value = ciConstant(mirror->float_field(_offset));
+break;
+case T_DOUBLE:
+_constant_value = ciConstant(mirror->double_field(_offset));
+break;
+case T_LONG:
+_constant_value = ciConstant(mirror->long_field(_offset));
+break;
+case T_OBJECT:
+case T_ARRAY:
+{
+oop o = mirror->obj_field(_offset);
+// A field will be "constant" if it is known always to be
+// a non-null reference to an instance of a particular class,
+// or to a particular array.  This can happen even if the instance
+// or array is not perm.  In such a case, an "unloaded" ciArray
+// or ciInstance is created.  The compiler may be able to use
+// information about the object's class (which is exact) or length.
+if (o == NULL) {
+_constant_value = ciConstant(type()->basic_type(), ciNullObject::make());
+} else {
+_constant_value = ciConstant(type()->basic_type(), CURRENT_ENV->get_object(o));
+assert(_constant_value.as_object() == CURRENT_ENV->get_object(o), "check interning");
+}
+}
+}
+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;
+}
+}
+// ------------------------------------------------------------------
+// ciField::compute_type
+//
+// Lazily compute the type, if it is an instance klass.
+ciType* ciField::compute_type() {
+GUARDED_VM_ENTRY(return compute_type_impl();)
+}
+ciType* ciField::compute_type_impl() {
+ciKlass* type = CURRENT_ENV->get_klass_by_name_impl(_holder, constantPoolHandle(), _signature, false);
+if (!type->is_primitive_type() && is_shared()) {
+// We must not cache a pointer to an unshared type, in a shared field.
+bool type_is_also_shared = false;
+if (type->is_type_array_klass()) {
+type_is_also_shared = true;  // int[] etc. are explicitly bootstrapped
+} else if (type->is_instance_klass()) {
+type_is_also_shared = type->as_instance_klass()->is_shared();
+} else {
+// Currently there is no 'shared' query for array types.
+type_is_also_shared = !ciObjectFactory::is_initialized();
+}
+if (!type_is_also_shared)
+return type;              // Bummer.
+}
+_type = type;
+return type;
+}
+// ------------------------------------------------------------------
+// ciField::will_link
+//
+// Can a specific access to this field be made without causing
+// link errors?
+bool ciField::will_link(ciInstanceKlass* accessing_klass,
+Bytecodes::Code bc) {
+VM_ENTRY_MARK;
+assert(bc == Bytecodes::_getstatic || bc == Bytecodes::_putstatic ||
+bc == Bytecodes::_getfield  || bc == Bytecodes::_putfield,
+"unexpected bytecode");
+if (_offset == -1) {
+// at creation we couldn't link to our holder so we need to
+// maintain that stance, otherwise there's no safe way to use this
+// ciField.
+return false;
+}
+// Check for static/nonstatic mismatch
+bool is_static = (bc == Bytecodes::_getstatic || bc == Bytecodes::_putstatic);
+if (is_static != this->is_static()) {
+return false;
+}
+// Get and put can have different accessibility rules
+bool is_put    = (bc == Bytecodes::_putfield  || bc == Bytecodes::_putstatic);
+if (is_put) {
+if (_known_to_link_with_put == accessing_klass) {
+return true;
+}
+} else {
+if (_known_to_link_with_get == accessing_klass) {
+return true;
+}
+}
+fieldDescriptor result;
+LinkResolver::resolve_field(result, _holder->get_instanceKlass(),
+_name->get_symbol(), _signature->get_symbol(),
+accessing_klass->get_Klass(), bc, true, false,
+KILL_COMPILE_ON_FATAL_(false));
+// update the hit-cache, unless there is a problem with memory scoping:
+if (accessing_klass->is_shared() || !is_shared()) {
+if (is_put) {
+_known_to_link_with_put = accessing_klass;
+} else {
+_known_to_link_with_get = accessing_klass;
+}
+}
+return true;
+}
+// ------------------------------------------------------------------
+// ciField::print
+void ciField::print() {
+tty->print("<ciField name=");
+_holder->print_name();
+tty->print(".");
+_name->print_symbol();
+tty->print(" signature=");
+_signature->print_symbol();
+tty->print(" offset=%d type=", _offset);
+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=");
+_constant_value.print();
+}
+tty->print(">");
+}
+// ------------------------------------------------------------------
+// ciField::print_name_on
+//
+// Print the name of this field
+void ciField::print_name_on(outputStream* st) {
+name()->print_symbol_on(st);
+}

Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/ci/ciField.cpp

src/share/vm/ci/ciField.cpp