779 lines
26 KiB
C++
779 lines
26 KiB
C++
/*
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* Copyright (c) 1997, 2015, 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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*
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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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*
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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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*
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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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*
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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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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "classfile/stackMapTableFormat.hpp"
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#include "interpreter/bytecodes.hpp"
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#include "memory/metadataFactory.hpp"
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#include "memory/oopFactory.hpp"
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#include "memory/universe.inline.hpp"
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#include "oops/oop.inline.hpp"
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#include "runtime/handles.inline.hpp"
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#include "runtime/relocator.hpp"
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#define MAX_METHOD_LENGTH 65535
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#define MAX_SHORT ((1 << 15) - 1)
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#define MIN_SHORT (- (1 << 15))
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// Encapsulates a code change request. There are 3 types.
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// General instruction, jump instruction, and table/lookup switches
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//
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class ChangeItem : public ResourceObj {
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int _bci;
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public:
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ChangeItem(int bci) { _bci = bci; }
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virtual bool handle_code_change(Relocator *r) = 0;
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// type info
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virtual bool is_widen() { return false; }
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virtual bool is_jump_widen() { return false; }
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virtual bool is_switch_pad() { return false; }
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// accessors
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int bci() { return _bci; }
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void relocate(int break_bci, int delta) { if (_bci > break_bci) { _bci += delta; } }
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virtual bool adjust(int bci, int delta) { return false; }
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// debug
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virtual void print() = 0;
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};
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class ChangeWiden : public ChangeItem {
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int _new_ilen; // New length of instruction at bci
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u_char* _inst_buffer; // New bytecodes
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public:
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ChangeWiden(int bci, int new_ilen, u_char* inst_buffer) : ChangeItem(bci) {
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_new_ilen = new_ilen;
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_inst_buffer = inst_buffer;
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}
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// Callback to do instruction
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bool handle_code_change(Relocator *r) { return r->handle_widen(bci(), _new_ilen, _inst_buffer); };
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bool is_widen() { return true; }
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void print() { tty->print_cr("ChangeWiden. bci: %d New_ilen: %d", bci(), _new_ilen); }
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};
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class ChangeJumpWiden : public ChangeItem {
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int _delta; // New length of instruction at bci
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public:
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ChangeJumpWiden(int bci, int delta) : ChangeItem(bci) { _delta = delta; }
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// Callback to do instruction
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bool handle_code_change(Relocator *r) { return r->handle_jump_widen(bci(), _delta); };
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bool is_jump_widen() { return true; }
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// If the bci matches, adjust the delta in the change jump request.
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bool adjust(int jump_bci, int delta) {
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if (bci() == jump_bci) {
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if (_delta > 0)
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_delta += delta;
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else
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_delta -= delta;
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return true;
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}
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return false;
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}
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void print() { tty->print_cr("ChangeJumpWiden. bci: %d Delta: %d", bci(), _delta); }
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};
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class ChangeSwitchPad : public ChangeItem {
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int _padding;
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bool _is_lookup_switch;
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public:
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ChangeSwitchPad(int bci, int padding, bool is_lookup_switch) : ChangeItem(bci) {
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_padding = padding;
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_is_lookup_switch = is_lookup_switch;
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}
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// Callback to do instruction
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bool handle_code_change(Relocator *r) { return r->handle_switch_pad(bci(), _padding, _is_lookup_switch); };
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bool is_switch_pad() { return true; }
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int padding() { return _padding; }
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bool is_lookup_switch() { return _is_lookup_switch; }
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void print() { tty->print_cr("ChangeSwitchPad. bci: %d Padding: %d IsLookupSwitch: %d", bci(), _padding, _is_lookup_switch); }
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};
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//-----------------------------------------------------------------------------------------------------------
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// Relocator code
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Relocator::Relocator(const methodHandle& m, RelocatorListener* listener) {
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set_method(m);
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set_code_length(method()->code_size());
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set_code_array(NULL);
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// Allocate code array and copy bytecodes
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if (!expand_code_array(0)) {
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// Should have at least MAX_METHOD_LENGTH available or the verifier
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// would have failed.
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ShouldNotReachHere();
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}
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set_compressed_line_number_table(NULL);
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set_compressed_line_number_table_size(0);
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_listener = listener;
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}
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// size is the new size of the instruction at bci. Hence, if size is less than the current
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// instruction size, we will shrink the code.
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methodHandle Relocator::insert_space_at(int bci, int size, u_char inst_buffer[], TRAPS) {
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_changes = new GrowableArray<ChangeItem*> (10);
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_changes->push(new ChangeWiden(bci, size, inst_buffer));
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if (TraceRelocator) {
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tty->print_cr("Space at: %d Size: %d", bci, size);
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_method->print();
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_method->print_codes();
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tty->print_cr("-------------------------------------------------");
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}
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if (!handle_code_changes()) return methodHandle();
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// Construct the new method
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methodHandle new_method = Method::clone_with_new_data(method(),
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code_array(), code_length(),
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compressed_line_number_table(),
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compressed_line_number_table_size(),
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CHECK_(methodHandle()));
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// Deallocate the old Method* from metadata
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ClassLoaderData* loader_data = method()->method_holder()->class_loader_data();
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loader_data->add_to_deallocate_list(method()());
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set_method(new_method);
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if (TraceRelocator) {
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tty->print_cr("-------------------------------------------------");
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tty->print_cr("new method");
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_method->print_codes();
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}
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return new_method;
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}
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bool Relocator::handle_code_changes() {
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assert(_changes != NULL, "changes vector must be initialized");
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while (!_changes->is_empty()) {
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// Inv: everything is aligned.
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ChangeItem* ci = _changes->first();
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if (TraceRelocator) {
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ci->print();
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}
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// Execute operation
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if (!ci->handle_code_change(this)) return false;
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// Shuffle items up
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for (int index = 1; index < _changes->length(); index++) {
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_changes->at_put(index-1, _changes->at(index));
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}
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_changes->pop();
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}
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return true;
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}
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bool Relocator::is_opcode_lookupswitch(Bytecodes::Code bc) {
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switch (bc) {
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case Bytecodes::_tableswitch: return false;
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case Bytecodes::_lookupswitch: // not rewritten on ia64
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case Bytecodes::_fast_linearswitch: // rewritten _lookupswitch
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case Bytecodes::_fast_binaryswitch: return true; // rewritten _lookupswitch
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default: ShouldNotReachHere();
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}
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return true; // dummy
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}
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// We need a special instruction size method, since lookupswitches and tableswitches might not be
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// properly aligned during relocation
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int Relocator::rc_instr_len(int bci) {
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Bytecodes::Code bc= code_at(bci);
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switch (bc) {
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// In the case of switch instructions, see if we have the original
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// padding recorded.
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case Bytecodes::_tableswitch:
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case Bytecodes::_lookupswitch:
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case Bytecodes::_fast_linearswitch:
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case Bytecodes::_fast_binaryswitch:
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{
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int pad = get_orig_switch_pad(bci, is_opcode_lookupswitch(bc));
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if (pad == -1) {
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return instruction_length_at(bci);
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}
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// Otherwise, depends on the switch type.
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switch (bc) {
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case Bytecodes::_tableswitch: {
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int lo = int_at(bci + 1 + pad + 4 * 1);
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int hi = int_at(bci + 1 + pad + 4 * 2);
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int n = hi - lo + 1;
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return 1 + pad + 4*(3 + n);
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}
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case Bytecodes::_lookupswitch:
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case Bytecodes::_fast_linearswitch:
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case Bytecodes::_fast_binaryswitch: {
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int npairs = int_at(bci + 1 + pad + 4 * 1);
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return 1 + pad + 4*(2 + 2*npairs);
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}
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default:
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ShouldNotReachHere();
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}
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}
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}
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return instruction_length_at(bci);
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}
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// If a change item is recorded for "pc", with type "ct", returns the
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// associated padding, else -1.
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int Relocator::get_orig_switch_pad(int bci, bool is_lookup_switch) {
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for (int k = 0; k < _changes->length(); k++) {
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ChangeItem* ci = _changes->at(k);
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if (ci->is_switch_pad()) {
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ChangeSwitchPad* csp = (ChangeSwitchPad*)ci;
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if (csp->is_lookup_switch() == is_lookup_switch && csp->bci() == bci) {
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return csp->padding();
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}
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}
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}
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return -1;
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}
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// Push a ChangeJumpWiden if it doesn't already exist on the work queue,
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// otherwise adjust the item already there by delta. The calculation for
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// new_delta is wrong for this because it uses the offset stored in the
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// code stream itself which wasn't fixed when item was pushed on the work queue.
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void Relocator::push_jump_widen(int bci, int delta, int new_delta) {
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for (int j = 0; j < _changes->length(); j++) {
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ChangeItem* ci = _changes->at(j);
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if (ci->adjust(bci, delta)) return;
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}
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_changes->push(new ChangeJumpWiden(bci, new_delta));
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}
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// The current instruction of "c" is a jump; one of its offset starts
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// at "offset" and is a short if "isShort" is "TRUE",
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// and an integer otherwise. If the jump crosses "breakPC", change
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// the span of the jump by "delta".
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void Relocator::change_jump(int bci, int offset, bool is_short, int break_bci, int delta) {
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int bci_delta = (is_short) ? short_at(offset) : int_at(offset);
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int targ = bci + bci_delta;
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if ((bci <= break_bci && targ > break_bci) ||
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(bci > break_bci && targ <= break_bci)) {
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int new_delta;
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if (bci_delta > 0)
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new_delta = bci_delta + delta;
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else
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new_delta = bci_delta - delta;
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if (is_short && ((new_delta > MAX_SHORT) || new_delta < MIN_SHORT)) {
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push_jump_widen(bci, delta, new_delta);
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} else if (is_short) {
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short_at_put(offset, new_delta);
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} else {
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int_at_put(offset, new_delta);
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}
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}
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}
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// Changes all jumps crossing "break_bci" by "delta". May enqueue things
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// on "rc->changes"
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void Relocator::change_jumps(int break_bci, int delta) {
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int bci = 0;
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Bytecodes::Code bc;
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// Now, adjust any affected instructions.
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while (bci < code_length()) {
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switch (bc= code_at(bci)) {
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case Bytecodes::_ifeq:
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case Bytecodes::_ifne:
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case Bytecodes::_iflt:
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case Bytecodes::_ifge:
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case Bytecodes::_ifgt:
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case Bytecodes::_ifle:
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case Bytecodes::_if_icmpeq:
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case Bytecodes::_if_icmpne:
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case Bytecodes::_if_icmplt:
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case Bytecodes::_if_icmpge:
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case Bytecodes::_if_icmpgt:
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case Bytecodes::_if_icmple:
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case Bytecodes::_if_acmpeq:
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case Bytecodes::_if_acmpne:
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case Bytecodes::_ifnull:
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case Bytecodes::_ifnonnull:
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case Bytecodes::_goto:
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case Bytecodes::_jsr:
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change_jump(bci, bci+1, true, break_bci, delta);
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break;
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case Bytecodes::_goto_w:
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case Bytecodes::_jsr_w:
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change_jump(bci, bci+1, false, break_bci, delta);
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break;
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case Bytecodes::_tableswitch:
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case Bytecodes::_lookupswitch:
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case Bytecodes::_fast_linearswitch:
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case Bytecodes::_fast_binaryswitch: {
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int recPad = get_orig_switch_pad(bci, (bc != Bytecodes::_tableswitch));
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int oldPad = (recPad != -1) ? recPad : align(bci+1) - (bci+1);
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if (bci > break_bci) {
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int new_bci = bci + delta;
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int newPad = align(new_bci+1) - (new_bci+1);
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// Do we need to check the padding?
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if (newPad != oldPad) {
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if (recPad == -1) {
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_changes->push(new ChangeSwitchPad(bci, oldPad, (bc != Bytecodes::_tableswitch)));
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}
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}
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}
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// Then the rest, which depend on the kind of switch.
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switch (bc) {
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case Bytecodes::_tableswitch: {
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change_jump(bci, bci +1 + oldPad, false, break_bci, delta);
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// We cannot use the Bytecode_tableswitch abstraction, since the padding might not be correct.
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int lo = int_at(bci + 1 + oldPad + 4 * 1);
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int hi = int_at(bci + 1 + oldPad + 4 * 2);
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int n = hi - lo + 1;
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for (int k = 0; k < n; k++) {
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change_jump(bci, bci +1 + oldPad + 4*(k+3), false, break_bci, delta);
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}
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// Special next-bci calculation here...
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bci += 1 + oldPad + (n+3)*4;
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continue;
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}
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case Bytecodes::_lookupswitch:
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case Bytecodes::_fast_linearswitch:
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case Bytecodes::_fast_binaryswitch: {
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change_jump(bci, bci +1 + oldPad, false, break_bci, delta);
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// We cannot use the Bytecode_lookupswitch abstraction, since the padding might not be correct.
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int npairs = int_at(bci + 1 + oldPad + 4 * 1);
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for (int k = 0; k < npairs; k++) {
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change_jump(bci, bci + 1 + oldPad + 4*(2 + 2*k + 1), false, break_bci, delta);
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}
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/* Special next-bci calculation here... */
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bci += 1 + oldPad + (2 + (npairs*2))*4;
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continue;
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}
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default:
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ShouldNotReachHere();
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}
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}
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default:
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break;
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}
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bci += rc_instr_len(bci);
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}
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}
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// The width of instruction at "pc" is changing by "delta". Adjust the
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// exception table, if any, of "rc->mb".
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void Relocator::adjust_exception_table(int bci, int delta) {
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ExceptionTable table(_method());
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for (int index = 0; index < table.length(); index ++) {
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if (table.start_pc(index) > bci) {
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table.set_start_pc(index, table.start_pc(index) + delta);
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table.set_end_pc(index, table.end_pc(index) + delta);
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} else if (bci < table.end_pc(index)) {
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table.set_end_pc(index, table.end_pc(index) + delta);
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}
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if (table.handler_pc(index) > bci)
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table.set_handler_pc(index, table.handler_pc(index) + delta);
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}
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}
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// The width of instruction at "bci" is changing by "delta". Adjust the line number table.
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void Relocator::adjust_line_no_table(int bci, int delta) {
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if (method()->has_linenumber_table()) {
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CompressedLineNumberReadStream reader(method()->compressed_linenumber_table());
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CompressedLineNumberWriteStream writer(64); // plenty big for most line number tables
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while (reader.read_pair()) {
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int adjustment = (reader.bci() > bci) ? delta : 0;
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writer.write_pair(reader.bci() + adjustment, reader.line());
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}
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writer.write_terminator();
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set_compressed_line_number_table(writer.buffer());
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set_compressed_line_number_table_size(writer.position());
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}
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}
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// The width of instruction at "bci" is changing by "delta". Adjust the local variable table.
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void Relocator::adjust_local_var_table(int bci, int delta) {
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int localvariable_table_length = method()->localvariable_table_length();
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if (localvariable_table_length > 0) {
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LocalVariableTableElement* table = method()->localvariable_table_start();
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for (int i = 0; i < localvariable_table_length; i++) {
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u2 current_bci = table[i].start_bci;
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if (current_bci > bci) {
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table[i].start_bci = current_bci + delta;
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} else {
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u2 current_length = table[i].length;
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if (current_bci + current_length > bci) {
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table[i].length = current_length + delta;
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}
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}
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}
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}
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}
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// Create a new array, copying the src array but adding a hole at
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// the specified location
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static Array<u1>* insert_hole_at(ClassLoaderData* loader_data,
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size_t where, int hole_sz, Array<u1>* src) {
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Thread* THREAD = Thread::current();
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Array<u1>* dst =
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MetadataFactory::new_array<u1>(loader_data, src->length() + hole_sz, 0, CHECK_NULL);
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address src_addr = (address)src->adr_at(0);
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address dst_addr = (address)dst->adr_at(0);
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memcpy(dst_addr, src_addr, where);
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memcpy(dst_addr + where + hole_sz,
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src_addr + where, src->length() - where);
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return dst;
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}
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// The width of instruction at "bci" is changing by "delta". Adjust the stack
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// map frames.
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void Relocator::adjust_stack_map_table(int bci, int delta) {
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if (method()->has_stackmap_table()) {
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Array<u1>* data = method()->stackmap_data();
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// The data in the array is a classfile representation of the stackmap table
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stack_map_table* sm_table =
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stack_map_table::at((address)data->adr_at(0));
|
|
|
|
int count = sm_table->number_of_entries();
|
|
stack_map_frame* frame = sm_table->entries();
|
|
int bci_iter = -1;
|
|
bool offset_adjusted = false; // only need to adjust one offset
|
|
|
|
for (int i = 0; i < count; ++i) {
|
|
int offset_delta = frame->offset_delta();
|
|
bci_iter += offset_delta;
|
|
|
|
if (!offset_adjusted && bci_iter > bci) {
|
|
int new_offset_delta = offset_delta + delta;
|
|
|
|
if (frame->is_valid_offset(new_offset_delta)) {
|
|
frame->set_offset_delta(new_offset_delta);
|
|
} else {
|
|
assert(frame->is_same_frame() ||
|
|
frame->is_same_locals_1_stack_item_frame(),
|
|
"Frame must be one of the compressed forms");
|
|
// The new delta exceeds the capacity of the 'same_frame' or
|
|
// 'same_frame_1_stack_item_frame' frame types. We need to
|
|
// convert these frames to the extended versions, but the extended
|
|
// version is bigger and requires more room. So we allocate a
|
|
// new array and copy the data, being sure to leave u2-sized hole
|
|
// right after the 'frame_type' for the new offset field.
|
|
//
|
|
// We can safely ignore the reverse situation as a small delta
|
|
// can still be used in an extended version of the frame.
|
|
|
|
size_t frame_offset = (address)frame - (address)data->adr_at(0);
|
|
|
|
ClassLoaderData* loader_data = method()->method_holder()->class_loader_data();
|
|
Array<u1>* new_data = insert_hole_at(loader_data, frame_offset + 1, 2, data);
|
|
if (new_data == NULL) {
|
|
return; // out-of-memory?
|
|
}
|
|
// Deallocate old data
|
|
MetadataFactory::free_array<u1>(loader_data, data);
|
|
data = new_data;
|
|
|
|
address frame_addr = (address)(data->adr_at(0) + frame_offset);
|
|
frame = stack_map_frame::at(frame_addr);
|
|
|
|
|
|
// Now convert the frames in place
|
|
if (frame->is_same_frame()) {
|
|
same_frame_extended::create_at(frame_addr, new_offset_delta);
|
|
} else {
|
|
same_locals_1_stack_item_extended::create_at(
|
|
frame_addr, new_offset_delta, NULL);
|
|
// the verification_info_type should already be at the right spot
|
|
}
|
|
}
|
|
offset_adjusted = true; // needs to be done only once, since subsequent
|
|
// values are offsets from the current
|
|
}
|
|
|
|
// The stack map frame may contain verification types, if so we need to
|
|
// check and update any Uninitialized type's bci (no matter where it is).
|
|
int number_of_types = frame->number_of_types();
|
|
verification_type_info* types = frame->types();
|
|
|
|
for (int i = 0; i < number_of_types; ++i) {
|
|
if (types->is_uninitialized() && types->bci() > bci) {
|
|
types->set_bci(types->bci() + delta);
|
|
}
|
|
types = types->next();
|
|
}
|
|
|
|
// Full frame has stack values too
|
|
full_frame* ff = frame->as_full_frame();
|
|
if (ff != NULL) {
|
|
address eol = (address)types;
|
|
number_of_types = ff->stack_slots(eol);
|
|
types = ff->stack(eol);
|
|
for (int i = 0; i < number_of_types; ++i) {
|
|
if (types->is_uninitialized() && types->bci() > bci) {
|
|
types->set_bci(types->bci() + delta);
|
|
}
|
|
types = types->next();
|
|
}
|
|
}
|
|
|
|
frame = frame->next();
|
|
}
|
|
|
|
method()->set_stackmap_data(data); // in case it has changed
|
|
}
|
|
}
|
|
|
|
|
|
bool Relocator::expand_code_array(int delta) {
|
|
int length = MAX2(code_length() + delta, code_length() * (100+code_slop_pct()) / 100);
|
|
|
|
if (length > MAX_METHOD_LENGTH) {
|
|
if (delta == 0 && code_length() <= MAX_METHOD_LENGTH) {
|
|
length = MAX_METHOD_LENGTH;
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
unsigned char* new_code_array = NEW_RESOURCE_ARRAY(unsigned char, length);
|
|
if (!new_code_array) return false;
|
|
|
|
// Expanding current array
|
|
if (code_array() != NULL) {
|
|
memcpy(new_code_array, code_array(), code_length());
|
|
} else {
|
|
// Initial copy. Copy directly from Method*
|
|
memcpy(new_code_array, method()->code_base(), code_length());
|
|
}
|
|
|
|
set_code_array(new_code_array);
|
|
set_code_array_length(length);
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
// The instruction at "bci", whose size is "ilen", is changing size by
|
|
// "delta". Reallocate, move code, recalculate jumps, and enqueue
|
|
// change items as necessary.
|
|
bool Relocator::relocate_code(int bci, int ilen, int delta) {
|
|
int next_bci = bci + ilen;
|
|
if (delta > 0 && code_length() + delta > code_array_length()) {
|
|
// Expand allocated code space, if necessary.
|
|
if (!expand_code_array(delta)) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// We require 4-byte alignment of code arrays.
|
|
assert(((intptr_t)code_array() & 3) == 0, "check code alignment");
|
|
// Change jumps before doing the copying; this routine requires aligned switches.
|
|
change_jumps(bci, delta);
|
|
|
|
// In case we have shrunken a tableswitch/lookupswitch statement, we store the last
|
|
// bytes that get overwritten. We have to copy the bytes after the change_jumps method
|
|
// has been called, since it is likely to update last offset in a tableswitch/lookupswitch
|
|
if (delta < 0) {
|
|
assert(delta>=-3, "we cannot overwrite more than 3 bytes");
|
|
memcpy(_overwrite, addr_at(bci + ilen + delta), -delta);
|
|
}
|
|
|
|
memmove(addr_at(next_bci + delta), addr_at(next_bci), code_length() - next_bci);
|
|
set_code_length(code_length() + delta);
|
|
// Also adjust exception tables...
|
|
adjust_exception_table(bci, delta);
|
|
// Line number tables...
|
|
adjust_line_no_table(bci, delta);
|
|
// And local variable table...
|
|
adjust_local_var_table(bci, delta);
|
|
|
|
// Adjust stack maps
|
|
adjust_stack_map_table(bci, delta);
|
|
|
|
// Relocate the pending change stack...
|
|
for (int j = 0; j < _changes->length(); j++) {
|
|
ChangeItem* ci = _changes->at(j);
|
|
ci->relocate(bci, delta);
|
|
}
|
|
|
|
// Notify any listeners about code relocation
|
|
notify(bci, delta, code_length());
|
|
|
|
return true;
|
|
}
|
|
|
|
// relocate a general instruction. Called by ChangeWiden class
|
|
bool Relocator::handle_widen(int bci, int new_ilen, u_char inst_buffer[]) {
|
|
int ilen = rc_instr_len(bci);
|
|
if (!relocate_code(bci, ilen, new_ilen - ilen))
|
|
return false;
|
|
|
|
// Insert new bytecode(s)
|
|
for(int k = 0; k < new_ilen; k++) {
|
|
code_at_put(bci + k, (Bytecodes::Code)inst_buffer[k]);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// handle jump_widen instruction. Called be ChangeJumpWiden class
|
|
bool Relocator::handle_jump_widen(int bci, int delta) {
|
|
int ilen = rc_instr_len(bci);
|
|
|
|
Bytecodes::Code bc = code_at(bci);
|
|
switch (bc) {
|
|
case Bytecodes::_ifeq:
|
|
case Bytecodes::_ifne:
|
|
case Bytecodes::_iflt:
|
|
case Bytecodes::_ifge:
|
|
case Bytecodes::_ifgt:
|
|
case Bytecodes::_ifle:
|
|
case Bytecodes::_if_icmpeq:
|
|
case Bytecodes::_if_icmpne:
|
|
case Bytecodes::_if_icmplt:
|
|
case Bytecodes::_if_icmpge:
|
|
case Bytecodes::_if_icmpgt:
|
|
case Bytecodes::_if_icmple:
|
|
case Bytecodes::_if_acmpeq:
|
|
case Bytecodes::_if_acmpne:
|
|
case Bytecodes::_ifnull:
|
|
case Bytecodes::_ifnonnull: {
|
|
const int goto_length = Bytecodes::length_for(Bytecodes::_goto);
|
|
|
|
// If 'if' points to the next bytecode after goto, it's already handled.
|
|
// it shouldn't be.
|
|
assert (short_at(bci+1) != ilen+goto_length, "if relocation already handled");
|
|
assert(ilen == 3, "check length");
|
|
|
|
// Convert to 0 if <cond> goto 6
|
|
// 3 _goto 11
|
|
// 6 _goto_w <wide delta offset>
|
|
// 11 <else code>
|
|
const int goto_w_length = Bytecodes::length_for(Bytecodes::_goto_w);
|
|
const int add_bci = goto_length + goto_w_length;
|
|
|
|
if (!relocate_code(bci, 3, /*delta*/add_bci)) return false;
|
|
|
|
// if bytecode points to goto_w instruction
|
|
short_at_put(bci + 1, ilen + goto_length);
|
|
|
|
int cbci = bci + ilen;
|
|
// goto around
|
|
code_at_put(cbci, Bytecodes::_goto);
|
|
short_at_put(cbci + 1, add_bci);
|
|
// goto_w <wide delta>
|
|
cbci = cbci + goto_length;
|
|
code_at_put(cbci, Bytecodes::_goto_w);
|
|
if (delta > 0) {
|
|
delta += 2; // goto_w is 2 bytes more than "if" code
|
|
} else {
|
|
delta -= ilen+goto_length; // branch starts at goto_w offset
|
|
}
|
|
int_at_put(cbci + 1, delta);
|
|
break;
|
|
|
|
}
|
|
case Bytecodes::_goto:
|
|
case Bytecodes::_jsr:
|
|
assert(ilen == 3, "check length");
|
|
|
|
if (!relocate_code(bci, 3, 2)) return false;
|
|
if (bc == Bytecodes::_goto)
|
|
code_at_put(bci, Bytecodes::_goto_w);
|
|
else
|
|
code_at_put(bci, Bytecodes::_jsr_w);
|
|
|
|
// If it's a forward jump, add 2 for the widening.
|
|
if (delta > 0) delta += 2;
|
|
int_at_put(bci + 1, delta);
|
|
break;
|
|
|
|
default: ShouldNotReachHere();
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// handle lookup/table switch instructions. Called be ChangeSwitchPad class
|
|
bool Relocator::handle_switch_pad(int bci, int old_pad, bool is_lookup_switch) {
|
|
int ilen = rc_instr_len(bci);
|
|
int new_pad = align(bci+1) - (bci+1);
|
|
int pad_delta = new_pad - old_pad;
|
|
if (pad_delta != 0) {
|
|
int len;
|
|
if (!is_lookup_switch) {
|
|
int low = int_at(bci+1+old_pad+4);
|
|
int high = int_at(bci+1+old_pad+8);
|
|
len = high-low+1 + 3; // 3 for default, hi, lo.
|
|
} else {
|
|
int npairs = int_at(bci+1+old_pad+4);
|
|
len = npairs*2 + 2; // 2 for default, npairs.
|
|
}
|
|
// Because "relocateCode" does a "changeJumps" loop,
|
|
// which parses instructions to determine their length,
|
|
// we need to call that before messing with the current
|
|
// instruction. Since it may also overwrite the current
|
|
// instruction when moving down, remember the possibly
|
|
// overwritten part.
|
|
|
|
// Move the code following the instruction...
|
|
if (!relocate_code(bci, ilen, pad_delta)) return false;
|
|
|
|
if (pad_delta < 0) {
|
|
// Move the shrunken instruction down.
|
|
memmove(addr_at(bci + 1 + new_pad),
|
|
addr_at(bci + 1 + old_pad),
|
|
len * 4 + pad_delta);
|
|
memmove(addr_at(bci + 1 + new_pad + len*4 + pad_delta),
|
|
_overwrite, -pad_delta);
|
|
} else {
|
|
assert(pad_delta > 0, "check");
|
|
// Move the expanded instruction up.
|
|
memmove(addr_at(bci +1 + new_pad),
|
|
addr_at(bci +1 + old_pad),
|
|
len * 4);
|
|
memset(addr_at(bci + 1), 0, new_pad); // pad must be 0
|
|
}
|
|
}
|
|
return true;
|
|
}
|