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* Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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#include "precompiled.hpp"
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#include "asm/assembler.hpp"
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#include "classfile/symbolTable.hpp"
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#include "classfile/systemDictionary.hpp"
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#include "classfile/vmSymbols.hpp"
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#include "memory/oopFactory.hpp"
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#include "memory/resourceArea.hpp"
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#include "memory/universe.hpp"
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#include "oops/instanceKlass.hpp"
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#include "oops/klass.inline.hpp"
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#include "oops/oop.inline.hpp"
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#include "oops/symbol.hpp"
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#include "oops/typeArrayKlass.hpp"
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#include "runtime/fieldDescriptor.inline.hpp"
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#include "runtime/handles.inline.hpp"
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#include "runtime/safepointVerifiers.hpp"
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#include "runtime/sharedRuntime.hpp"
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#include "runtime/signature.hpp"
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#include "runtime/sharedRuntime.hpp"
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// Implementation of SignatureIterator
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// Signature = "(" {Parameter} ")" ReturnType.
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// Parameter = FieldType.
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// ReturnType = FieldType | "V".
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// FieldType = "B" | "C" | "D" | "F" | "I" | "J" | "S" | "Z" | "L" ClassName ";" | "[" FieldType.
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// The ClassName string can be any JVM-style UTF8 string except:
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// - an empty string (the empty string is never a name of any kind)
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// - a string which begins or ends with slash '/' (the package separator)
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// - a string which contains adjacent slashes '//' (no empty package names)
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// - a string which contains a semicolon ';' (the end-delimiter)
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// - a string which contains a left bracket '[' (the array marker)
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// - a string which contains a dot '.' (the external package separator)
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// Other "meta-looking" characters, such as '(' and '<' and '+',
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// are perfectly legitimate within a class name, for the JVM.
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// Class names which contain double slashes ('a//b') and non-initial
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// brackets ('a[b]') are reserved for possible enrichment of the
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void SignatureIterator::set_fingerprint(fingerprint_t fingerprint) {
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if (!fp_is_valid(fingerprint)) {
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_fingerprint = fingerprint;
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_return_type = T_ILLEGAL;
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} else if (fingerprint != _fingerprint) {
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assert(_fingerprint == zero_fingerprint(), "consistent fingerprint values");
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_fingerprint = fingerprint;
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_return_type = fp_return_type(fingerprint);
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BasicType SignatureIterator::return_type() {
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if (_return_type == T_ILLEGAL) {
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SignatureStream ss(_signature);
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ss.skip_to_return_type();
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_return_type = ss.type();
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assert(_return_type != T_ILLEGAL, "illegal return type");
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bool SignatureIterator::fp_is_valid_type(BasicType type, bool for_return_type) {
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assert(type != (BasicType)fp_parameters_done, "fingerprint is incorrectly at done");
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assert(((int)type & ~fp_parameter_feature_mask) == 0, "fingerprint feature mask yielded non-zero value");
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return (is_java_primitive(type) ||
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is_reference_type(type) ||
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(for_return_type && type == T_VOID));
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ArgumentSizeComputer::ArgumentSizeComputer(Symbol* signature)
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: SignatureIterator(signature)
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do_parameters_on(this); // non-virtual template execution
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ArgumentCount::ArgumentCount(Symbol* signature)
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: SignatureIterator(signature)
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do_parameters_on(this); // non-virtual template execution
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ReferenceArgumentCount::ReferenceArgumentCount(Symbol* signature)
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: SignatureIterator(signature)
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do_parameters_on(this); // non-virtual template execution
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#if !defined(_LP64) || defined(ZERO) || defined(ASSERT)
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static int compute_num_stack_arg_slots(Symbol* signature, int sizeargs, bool is_static) {
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BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
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VMRegPair* regs = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
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sig_bt[sig_index++] = T_OBJECT; // 'this'
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for (SignatureStream ss(signature); !ss.at_return_type(); ss.next()) {
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BasicType t = ss.type();
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assert(type2size[t] == 1 || type2size[t] == 2, "size is 1 or 2");
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sig_bt[sig_index++] = t;
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if (type2size[t] == 2) {
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sig_bt[sig_index++] = T_VOID;
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assert(sig_index == sizeargs, "sig_index: %d sizeargs: %d", sig_index, sizeargs);
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return SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs);
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void Fingerprinter::compute_fingerprint_and_return_type(bool static_flag) {
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// See if we fingerprinted this method already
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if (_method != nullptr) {
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assert(!static_flag, "must not be passed by caller");
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static_flag = _method->is_static();
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_fingerprint = _method->constMethod()->fingerprint();
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if (_fingerprint != zero_fingerprint()) {
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_return_type = _method->result_type();
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assert(is_java_type(_return_type), "return type must be a java type");
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if (_method->size_of_parameters() > fp_max_size_of_parameters) {
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_fingerprint = overflow_fingerprint();
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_method->constMethod()->set_fingerprint(_fingerprint);
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// as long as we are here compute the return type:
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_return_type = ResultTypeFinder(_method->signature()).type();
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assert(is_java_type(_return_type), "return type must be a java type");
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// Note: This will always take the slow path, since _fp==zero_fp.
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initialize_accumulator();
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initialize_calling_convention(static_flag);
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do_parameters_on(this);
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assert(fp_is_valid_type(_return_type, true), "bad result type");
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// Fill in the return type and static bits:
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_accumulator |= _return_type << fp_static_feature_size;
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_accumulator |= fp_is_static_bit;
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_param_size += 1; // this is the convention for Method::compute_size_of_parameters
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#if defined(_LP64) && !defined(ZERO)
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int dbg_stack_arg_slots = compute_num_stack_arg_slots(_signature, _param_size, static_flag);
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assert(_stack_arg_slots == dbg_stack_arg_slots, "fingerprinter: %d full: %d", _stack_arg_slots, dbg_stack_arg_slots);
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// Fallback: computed _stack_arg_slots is unreliable, compute directly.
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_stack_arg_slots = compute_num_stack_arg_slots(_signature, _param_size, static_flag);
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// Detect overflow. (We counted _param_size correctly.)
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if (_method == nullptr && _param_size > fp_max_size_of_parameters) {
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// We did a one-pass computation of argument size, return type,
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_fingerprint = overflow_fingerprint();
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assert(_shift_count < BitsPerLong,
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"shift count overflow %d (%d vs. %d): %s",
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_shift_count, _param_size, fp_max_size_of_parameters,
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_signature->as_C_string());
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assert((_accumulator >> _shift_count) == fp_parameters_done, "must be zero");
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// This is the result, along with _return_type:
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_fingerprint = _accumulator;
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// Cache the result on the method itself:
208
if (_method != nullptr) {
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_method->constMethod()->set_fingerprint(_fingerprint);
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void Fingerprinter::initialize_calling_convention(bool static_flag) {
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if (!static_flag) { // `this` takes up an int register
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void Fingerprinter::do_type_calling_convention(BasicType type) {
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// We compute the number of slots for stack-passed arguments in compiled calls.
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// TODO: SharedRuntime::java_calling_convention is the shared code that knows all details
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// about the platform-specific calling conventions. This method tries to compute the stack
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// args number... poorly, at least for 32-bit ports and for zero. Current code has the fallback
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// that recomputes the stack args number from SharedRuntime::java_calling_convention.
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#if defined(_LP64) && !defined(ZERO)
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if (_int_args < Argument::n_int_register_parameters_j) {
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#if defined(PPC64) || defined(S390)
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_stack_arg_slots += 1;
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_stack_arg_slots = align_up(_stack_arg_slots, 2);
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_stack_arg_slots += 1;
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#endif // defined(PPC64) || defined(S390)
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if (_int_args < Argument::n_int_register_parameters_j) {
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_stack_arg_slots = align_up(_stack_arg_slots, 2);
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_stack_arg_slots += 2;
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if (_fp_args < Argument::n_float_register_parameters_j) {
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#if defined(PPC64) || defined(S390)
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_stack_arg_slots += 1;
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_stack_arg_slots = align_up(_stack_arg_slots, 2);
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_stack_arg_slots += 1;
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#endif // defined(PPC64) || defined(S390)
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if (_fp_args < Argument::n_float_register_parameters_j) {
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_stack_arg_slots = align_up(_stack_arg_slots, 2);
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_stack_arg_slots += 2;
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ShouldNotReachHere();
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// Implementation of SignatureStream
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static inline BasicType decode_signature_char(int ch) {
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#define EACH_SIG(ch, bt, ignore) \
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SIGNATURE_TYPES_DO(EACH_SIG, ignore)
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SignatureStream::SignatureStream(const Symbol* signature,
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assert(!is_method || signature->starts_with(JVM_SIGNATURE_FUNC),
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"method signature required");
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_signature = signature;
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_limit = signature->utf8_length();
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int oz = (is_method ? _s_method : _s_field);
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_begin = _end = oz; // skip first '(' in method signatures
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_array_prefix = 0; // just for definiteness
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// assigning java/lang/Object to _previous_name means we can
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// avoid a number of null checks in the parser
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_previous_name = vmSymbols::java_lang_Object();
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SignatureStream::~SignatureStream() {
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if (_previous_name == vmSymbols::java_lang_Object()) {
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// no names were created
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assert(_names == nullptr, "_names unexpectedly created");
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// decrement refcount for names created during signature parsing
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_previous_name->decrement_refcount();
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if (_names != nullptr) {
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for (int i = 0; i < _names->length(); i++) {
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_names->at(i)->decrement_refcount();
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inline int SignatureStream::scan_type(BasicType type) {
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const u1* base = _signature->bytes();
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tem = (const u1*) memchr(&base[end], JVM_SIGNATURE_ENDCLASS, limit - end);
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return (tem == nullptr ? limit : pointer_delta_as_int(tem + 1, base));
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while ((end < limit) && ((char)base[end] == JVM_SIGNATURE_ARRAY)) { end++; }
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// If we discovered only the string of '[', this means something is wrong.
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assert(false, "Invalid type detected");
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_array_prefix = end - _end; // number of '[' chars just skipped
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if (Signature::has_envelope(base[end])) {
351
tem = (const u1 *) memchr(&base[end], JVM_SIGNATURE_ENDCLASS, limit - end);
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return (tem == nullptr ? limit : pointer_delta_as_int(tem + 1, base));
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// Skipping over a single character for a primitive type.
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assert(is_java_primitive(decode_signature_char(base[end])), "only primitives expected");
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// Skipping over a single character for a primitive type (or void).
360
assert(!is_reference_type(type), "only primitives or void expected");
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void SignatureStream::next() {
366
const Symbol* sig = _signature;
368
if (_end >= len) { set_done(); return; }
370
int ch = sig->char_at(_begin);
371
if (ch == JVM_SIGNATURE_ENDFUNC) {
372
assert(_state == _s_method, "must be in method");
373
_state = _s_method_return;
375
if (_end >= len) { set_done(); return; }
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ch = sig->char_at(_begin);
378
BasicType bt = decode_signature_char(ch);
379
assert(ch == type2char(bt), "bad signature char %c/%d", ch, ch);
381
_end = scan_type(bt);
384
int SignatureStream::skip_whole_array_prefix() {
385
assert(_type == T_ARRAY, "must be");
387
// we are stripping all levels of T_ARRAY,
388
// so we must decode the next character
389
int whole_array_prefix = _array_prefix;
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int new_begin = _begin + whole_array_prefix;
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int ch = _signature->char_at(new_begin);
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BasicType bt = decode_signature_char(ch);
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assert(ch == type2char(bt), "bad signature char %c/%d", ch, ch);
396
assert(bt != T_VOID && bt != T_ARRAY, "bad signature type");
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// Don't bother to re-scan, since it won't change the value of _end.
398
return whole_array_prefix;
401
bool Signature::is_valid_array_signature(const Symbol* sig) {
402
assert(sig->utf8_length() > 1, "this should already have been checked");
403
assert(sig->char_at(0) == JVM_SIGNATURE_ARRAY, "this should already have been checked");
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// The first character is already checked
406
int len = sig->utf8_length();
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// First skip all '['s
408
while(i < len - 1 && sig->char_at(i) == JVM_SIGNATURE_ARRAY) i++;
411
switch(sig->char_at(i)) {
412
case JVM_SIGNATURE_BYTE:
413
case JVM_SIGNATURE_CHAR:
414
case JVM_SIGNATURE_DOUBLE:
415
case JVM_SIGNATURE_FLOAT:
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case JVM_SIGNATURE_INT:
417
case JVM_SIGNATURE_LONG:
418
case JVM_SIGNATURE_SHORT:
419
case JVM_SIGNATURE_BOOLEAN:
420
// If it is an array, the type is the last character
421
return (i + 1 == len);
422
case JVM_SIGNATURE_CLASS:
423
// If it is an object, the last character must be a ';'
424
return sig->char_at(len - 1) == JVM_SIGNATURE_ENDCLASS;
429
BasicType Signature::basic_type(int ch) {
430
BasicType btcode = decode_signature_char(ch);
431
if (btcode == 0) return T_ILLEGAL;
435
Symbol* Signature::strip_envelope(const Symbol* signature) {
436
assert(has_envelope(signature), "precondition");
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return SymbolTable::new_symbol((char*) signature->bytes() + 1,
438
signature->utf8_length() - 2);
441
static const int jl_len = 10, object_len = 6, jl_object_len = jl_len + object_len;
442
static const char jl_str[] = "java/lang/";
445
static bool signature_symbols_sane() {
447
if (done) return true;
449
// test some tense code that looks for common symbol names:
450
assert(vmSymbols::java_lang_Object()->utf8_length() == jl_object_len &&
451
vmSymbols::java_lang_Object()->starts_with(jl_str, jl_len) &&
452
vmSymbols::java_lang_Object()->ends_with("Object", object_len) &&
453
vmSymbols::java_lang_Object()->is_permanent() &&
454
vmSymbols::java_lang_String()->utf8_length() == jl_object_len &&
455
vmSymbols::java_lang_String()->starts_with(jl_str, jl_len) &&
456
vmSymbols::java_lang_String()->ends_with("String", object_len) &&
457
vmSymbols::java_lang_String()->is_permanent(),
463
// returns a symbol; the caller is responsible for decrementing it
464
Symbol* SignatureStream::find_symbol() {
465
// Create a symbol from for string _begin _end
466
int begin = raw_symbol_begin();
467
int end = raw_symbol_end();
469
const char* symbol_chars = (const char*)_signature->base() + begin;
470
int len = end - begin;
472
// Quick check for common symbols in signatures
473
assert(signature_symbols_sane(), "incorrect signature sanity check");
474
if (len == jl_object_len &&
475
memcmp(symbol_chars, jl_str, jl_len) == 0) {
476
if (memcmp("String", symbol_chars + jl_len, object_len) == 0) {
477
return vmSymbols::java_lang_String();
478
} else if (memcmp("Object", symbol_chars + jl_len, object_len) == 0) {
479
return vmSymbols::java_lang_Object();
483
Symbol* name = _previous_name;
484
if (name->equals(symbol_chars, len)) {
488
// Save names for cleaning up reference count at the end of
489
// SignatureStream scope.
490
name = SymbolTable::new_symbol(symbol_chars, len);
492
// Only allocate the GrowableArray for the _names buffer if more than
493
// one name is being processed in the signature.
494
if (!_previous_name->is_permanent()) {
495
if (_names == nullptr) {
496
_names = new GrowableArray<Symbol*>(10);
498
_names->push(_previous_name);
500
_previous_name = name;
504
Klass* SignatureStream::as_klass(Handle class_loader, Handle protection_domain,
505
FailureMode failure_mode, TRAPS) {
506
if (!is_reference()) {
509
Symbol* name = as_symbol();
511
if (failure_mode == ReturnNull) {
512
// Note: SD::resolve_or_null returns null for most failure modes,
513
// but not all. Circularity errors, invalid PDs, etc., throw.
514
k = SystemDictionary::resolve_or_null(name, class_loader, protection_domain, CHECK_NULL);
515
} else if (failure_mode == CachedOrNull) {
516
NoSafepointVerifier nsv; // no loading, now, we mean it!
517
assert(!HAS_PENDING_EXCEPTION, "");
518
k = SystemDictionary::find_instance_klass(THREAD, name, class_loader, protection_domain);
519
// SD::find does not trigger loading, so there should be no throws
520
// Still, bad things can happen, so we CHECK_NULL and ask callers
524
// The only remaining failure mode is NCDFError.
525
// The test here allows for an additional mode CNFException
526
// if callers need to request the reflective error instead.
527
bool throw_error = (failure_mode == NCDFError);
528
k = SystemDictionary::resolve_or_fail(name, class_loader, protection_domain, throw_error, CHECK_NULL);
534
oop SignatureStream::as_java_mirror(Handle class_loader, Handle protection_domain,
535
FailureMode failure_mode, TRAPS) {
536
if (!is_reference()) {
537
return Universe::java_mirror(type());
539
Klass* klass = as_klass(class_loader, protection_domain, failure_mode, CHECK_NULL);
540
if (klass == nullptr) {
543
return klass->java_mirror();
546
void SignatureStream::skip_to_return_type() {
547
while (!at_return_type()) {
552
ResolvingSignatureStream::ResolvingSignatureStream(Symbol* signature,
554
Handle protection_domain,
556
: SignatureStream(signature, is_method),
557
_class_loader(class_loader), _protection_domain(protection_domain)
559
initialize_load_origin(nullptr);
562
ResolvingSignatureStream::ResolvingSignatureStream(Symbol* signature, Klass* load_origin, bool is_method)
563
: SignatureStream(signature, is_method)
565
assert(load_origin != nullptr, "");
566
initialize_load_origin(load_origin);
569
ResolvingSignatureStream::ResolvingSignatureStream(const Method* method)
570
: SignatureStream(method->signature(), true)
572
initialize_load_origin(method->method_holder());
575
void ResolvingSignatureStream::cache_handles() {
576
assert(_load_origin != nullptr, "");
577
JavaThread* current = JavaThread::current();
578
_class_loader = Handle(current, _load_origin->class_loader());
579
_protection_domain = Handle(current, _load_origin->protection_domain());
584
extern bool signature_constants_sane(); // called from basic_types_init()
586
bool signature_constants_sane() {
587
// for the lookup table, test every 8-bit code point, and then some:
588
for (int i = -256; i <= 256; i++) {
591
#define EACH_SIG(ch, bt, ignore) \
592
case ch: { btcode = bt; break; }
593
SIGNATURE_TYPES_DO(EACH_SIG, ignore)
596
int btc = decode_signature_char(i);
597
assert(btc == btcode, "misconfigured table: %d => %d not %d", i, btc, btcode);
602
bool SignatureVerifier::is_valid_method_signature(Symbol* sig) {
603
const char* method_sig = (const char*)sig->bytes();
604
ssize_t len = sig->utf8_length();
606
if (method_sig != nullptr && len > 1 && method_sig[index] == JVM_SIGNATURE_FUNC) {
608
while (index < len && method_sig[index] != JVM_SIGNATURE_ENDFUNC) {
609
ssize_t res = is_valid_type(&method_sig[index], len - index);
616
if (index < len && method_sig[index] == JVM_SIGNATURE_ENDFUNC) {
617
// check the return type
619
return (is_valid_type(&method_sig[index], len - index) == (len - index));
625
bool SignatureVerifier::is_valid_type_signature(Symbol* sig) {
626
const char* type_sig = (const char*)sig->bytes();
627
ssize_t len = sig->utf8_length();
628
return (type_sig != nullptr && len >= 1 &&
629
(is_valid_type(type_sig, len) == len));
632
// Checks to see if the type (not to go beyond 'limit') refers to a valid type.
633
// Returns -1 if it is not, or the index of the next character that is not part
634
// of the type. The type encoding may end before 'limit' and that's ok.
635
ssize_t SignatureVerifier::is_valid_type(const char* type, ssize_t limit) {
638
// Iterate over any number of array dimensions
639
while (index < limit && type[index] == JVM_SIGNATURE_ARRAY) ++index;
640
if (index >= limit) {
643
switch (type[index]) {
644
case JVM_SIGNATURE_BYTE:
645
case JVM_SIGNATURE_CHAR:
646
case JVM_SIGNATURE_FLOAT:
647
case JVM_SIGNATURE_DOUBLE:
648
case JVM_SIGNATURE_INT:
649
case JVM_SIGNATURE_LONG:
650
case JVM_SIGNATURE_SHORT:
651
case JVM_SIGNATURE_BOOLEAN:
652
case JVM_SIGNATURE_VOID:
654
case JVM_SIGNATURE_CLASS:
655
for (index = index + 1; index < limit; ++index) {
656
char c = type[index];
658
case JVM_SIGNATURE_ENDCLASS:
660
case '\0': case JVM_SIGNATURE_DOT: case JVM_SIGNATURE_ARRAY:
662
default: ; // fall through
666
default: ; // fall through