| /* |
| * Copyright (c) 1997, 2012, 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 "classfile/stackMapTableFormat.hpp" |
| #include "interpreter/bytecodes.hpp" |
| #include "memory/metadataFactory.hpp" |
| #include "memory/oopFactory.hpp" |
| #include "memory/universe.inline.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/handles.inline.hpp" |
| #include "runtime/relocator.hpp" |
| |
| #define MAX_METHOD_LENGTH 65535 |
| |
| #define MAX_SHORT ((1 << 15) - 1) |
| #define MIN_SHORT (- (1 << 15)) |
| |
| // Encapsulates a code change request. There are 3 types. |
| // General instruction, jump instruction, and table/lookup switches |
| // |
| class ChangeItem : public ResourceObj { |
| int _bci; |
| public: |
| ChangeItem(int bci) { _bci = bci; } |
| virtual bool handle_code_change(Relocator *r) = 0; |
| |
| // type info |
| virtual bool is_widen() { return false; } |
| virtual bool is_jump_widen() { return false; } |
| virtual bool is_switch_pad() { return false; } |
| |
| // accessors |
| int bci() { return _bci; } |
| void relocate(int break_bci, int delta) { if (_bci > break_bci) { _bci += delta; } } |
| |
| virtual bool adjust(int bci, int delta) { return false; } |
| |
| // debug |
| virtual void print() = 0; |
| }; |
| |
| class ChangeWiden : public ChangeItem { |
| int _new_ilen; // New length of instruction at bci |
| u_char* _inst_buffer; // New bytecodes |
| public: |
| ChangeWiden(int bci, int new_ilen, u_char* inst_buffer) : ChangeItem(bci) { |
| _new_ilen = new_ilen; |
| _inst_buffer = inst_buffer; |
| } |
| |
| // Callback to do instruction |
| bool handle_code_change(Relocator *r) { return r->handle_widen(bci(), _new_ilen, _inst_buffer); }; |
| |
| bool is_widen() { return true; } |
| |
| void print() { tty->print_cr("ChangeWiden. bci: %d New_ilen: %d", bci(), _new_ilen); } |
| }; |
| |
| class ChangeJumpWiden : public ChangeItem { |
| int _delta; // New length of instruction at bci |
| public: |
| ChangeJumpWiden(int bci, int delta) : ChangeItem(bci) { _delta = delta; } |
| |
| // Callback to do instruction |
| bool handle_code_change(Relocator *r) { return r->handle_jump_widen(bci(), _delta); }; |
| |
| bool is_jump_widen() { return true; } |
| |
| // If the bci matches, adjust the delta in the change jump request. |
| bool adjust(int jump_bci, int delta) { |
| if (bci() == jump_bci) { |
| if (_delta > 0) |
| _delta += delta; |
| else |
| _delta -= delta; |
| return true; |
| } |
| return false; |
| } |
| |
| void print() { tty->print_cr("ChangeJumpWiden. bci: %d Delta: %d", bci(), _delta); } |
| }; |
| |
| class ChangeSwitchPad : public ChangeItem { |
| int _padding; |
| bool _is_lookup_switch; |
| public: |
| ChangeSwitchPad(int bci, int padding, bool is_lookup_switch) : ChangeItem(bci) { |
| _padding = padding; |
| _is_lookup_switch = is_lookup_switch; |
| } |
| |
| // Callback to do instruction |
| bool handle_code_change(Relocator *r) { return r->handle_switch_pad(bci(), _padding, _is_lookup_switch); }; |
| |
| bool is_switch_pad() { return true; } |
| int padding() { return _padding; } |
| bool is_lookup_switch() { return _is_lookup_switch; } |
| |
| void print() { tty->print_cr("ChangeSwitchPad. bci: %d Padding: %d IsLookupSwitch: %d", bci(), _padding, _is_lookup_switch); } |
| }; |
| |
| //----------------------------------------------------------------------------------------------------------- |
| // Relocator code |
| |
| Relocator::Relocator(methodHandle m, RelocatorListener* listener) { |
| set_method(m); |
| set_code_length(method()->code_size()); |
| set_code_array(NULL); |
| // Allocate code array and copy bytecodes |
| if (!expand_code_array(0)) { |
| // Should have at least MAX_METHOD_LENGTH available or the verifier |
| // would have failed. |
| ShouldNotReachHere(); |
| } |
| set_compressed_line_number_table(NULL); |
| set_compressed_line_number_table_size(0); |
| _listener = listener; |
| } |
| |
| // size is the new size of the instruction at bci. Hence, if size is less than the current |
| // instruction sice, we will shrink the code. |
| methodHandle Relocator::insert_space_at(int bci, int size, u_char inst_buffer[], TRAPS) { |
| _changes = new GrowableArray<ChangeItem*> (10); |
| _changes->push(new ChangeWiden(bci, size, inst_buffer)); |
| |
| if (TraceRelocator) { |
| tty->print_cr("Space at: %d Size: %d", bci, size); |
| _method->print(); |
| _method->print_codes(); |
| tty->print_cr("-------------------------------------------------"); |
| } |
| |
| if (!handle_code_changes()) return methodHandle(); |
| |
| // Construct the new method |
| methodHandle new_method = Method::clone_with_new_data(method(), |
| code_array(), code_length(), |
| compressed_line_number_table(), |
| compressed_line_number_table_size(), |
| CHECK_(methodHandle())); |
| |
| // Deallocate the old Method* from metadata |
| ClassLoaderData* loader_data = method()->method_holder()->class_loader_data(); |
| loader_data->add_to_deallocate_list(method()()); |
| |
| set_method(new_method); |
| |
| if (TraceRelocator) { |
| tty->print_cr("-------------------------------------------------"); |
| tty->print_cr("new method"); |
| _method->print_codes(); |
| } |
| |
| return new_method; |
| } |
| |
| |
| bool Relocator::handle_code_changes() { |
| assert(_changes != NULL, "changes vector must be initialized"); |
| |
| while (!_changes->is_empty()) { |
| // Inv: everything is aligned. |
| ChangeItem* ci = _changes->first(); |
| |
| if (TraceRelocator) { |
| ci->print(); |
| } |
| |
| // Execute operation |
| if (!ci->handle_code_change(this)) return false; |
| |
| // Shuffel items up |
| for (int index = 1; index < _changes->length(); index++) { |
| _changes->at_put(index-1, _changes->at(index)); |
| } |
| _changes->pop(); |
| } |
| return true; |
| } |
| |
| |
| bool Relocator::is_opcode_lookupswitch(Bytecodes::Code bc) { |
| switch (bc) { |
| case Bytecodes::_tableswitch: return false; |
| case Bytecodes::_lookupswitch: // not rewritten on ia64 |
| case Bytecodes::_fast_linearswitch: // rewritten _lookupswitch |
| case Bytecodes::_fast_binaryswitch: return true; // rewritten _lookupswitch |
| default: ShouldNotReachHere(); |
| } |
| return true; // dummy |
| } |
| |
| // We need a special instruction size method, since lookupswitches and tableswitches might not be |
| // properly alligned during relocation |
| int Relocator::rc_instr_len(int bci) { |
| Bytecodes::Code bc= code_at(bci); |
| switch (bc) { |
| // In the case of switch instructions, see if we have the original |
| // padding recorded. |
| case Bytecodes::_tableswitch: |
| case Bytecodes::_lookupswitch: |
| case Bytecodes::_fast_linearswitch: |
| case Bytecodes::_fast_binaryswitch: |
| { |
| int pad = get_orig_switch_pad(bci, is_opcode_lookupswitch(bc)); |
| if (pad == -1) { |
| return instruction_length_at(bci); |
| } |
| // Otherwise, depends on the switch type. |
| switch (bc) { |
| case Bytecodes::_tableswitch: { |
| int lo = int_at(bci + 1 + pad + 4 * 1); |
| int hi = int_at(bci + 1 + pad + 4 * 2); |
| int n = hi - lo + 1; |
| return 1 + pad + 4*(3 + n); |
| } |
| case Bytecodes::_lookupswitch: |
| case Bytecodes::_fast_linearswitch: |
| case Bytecodes::_fast_binaryswitch: { |
| int npairs = int_at(bci + 1 + pad + 4 * 1); |
| return 1 + pad + 4*(2 + 2*npairs); |
| } |
| default: |
| ShouldNotReachHere(); |
| } |
| } |
| } |
| return instruction_length_at(bci); |
| } |
| |
| // If a change item is recorded for "pc", with type "ct", returns the |
| // associated padding, else -1. |
| int Relocator::get_orig_switch_pad(int bci, bool is_lookup_switch) { |
| for (int k = 0; k < _changes->length(); k++) { |
| ChangeItem* ci = _changes->at(k); |
| if (ci->is_switch_pad()) { |
| ChangeSwitchPad* csp = (ChangeSwitchPad*)ci; |
| if (csp->is_lookup_switch() == is_lookup_switch && csp->bci() == bci) { |
| return csp->padding(); |
| } |
| } |
| } |
| return -1; |
| } |
| |
| |
| // Push a ChangeJumpWiden if it doesn't already exist on the work queue, |
| // otherwise adjust the item already there by delta. The calculation for |
| // new_delta is wrong for this because it uses the offset stored in the |
| // code stream itself which wasn't fixed when item was pushed on the work queue. |
| void Relocator::push_jump_widen(int bci, int delta, int new_delta) { |
| for (int j = 0; j < _changes->length(); j++) { |
| ChangeItem* ci = _changes->at(j); |
| if (ci->adjust(bci, delta)) return; |
| } |
| _changes->push(new ChangeJumpWiden(bci, new_delta)); |
| } |
| |
| |
| // The current instruction of "c" is a jump; one of its offset starts |
| // at "offset" and is a short if "isShort" is "TRUE", |
| // and an integer otherwise. If the jump crosses "breakPC", change |
| // the span of the jump by "delta". |
| void Relocator::change_jump(int bci, int offset, bool is_short, int break_bci, int delta) { |
| int bci_delta = (is_short) ? short_at(offset) : int_at(offset); |
| int targ = bci + bci_delta; |
| |
| if ((bci <= break_bci && targ > break_bci) || |
| (bci > break_bci && targ <= break_bci)) { |
| int new_delta; |
| if (bci_delta > 0) |
| new_delta = bci_delta + delta; |
| else |
| new_delta = bci_delta - delta; |
| |
| if (is_short && ((new_delta > MAX_SHORT) || new_delta < MIN_SHORT)) { |
| push_jump_widen(bci, delta, new_delta); |
| } else if (is_short) { |
| short_at_put(offset, new_delta); |
| } else { |
| int_at_put(offset, new_delta); |
| } |
| } |
| } |
| |
| |
| // Changes all jumps crossing "break_bci" by "delta". May enqueue things |
| // on "rc->changes" |
| void Relocator::change_jumps(int break_bci, int delta) { |
| int bci = 0; |
| Bytecodes::Code bc; |
| // Now, adjust any affected instructions. |
| while (bci < code_length()) { |
| switch (bc= code_at(bci)) { |
| 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: |
| case Bytecodes::_goto: |
| case Bytecodes::_jsr: |
| change_jump(bci, bci+1, true, break_bci, delta); |
| break; |
| case Bytecodes::_goto_w: |
| case Bytecodes::_jsr_w: |
| change_jump(bci, bci+1, false, break_bci, delta); |
| break; |
| case Bytecodes::_tableswitch: |
| case Bytecodes::_lookupswitch: |
| case Bytecodes::_fast_linearswitch: |
| case Bytecodes::_fast_binaryswitch: { |
| int recPad = get_orig_switch_pad(bci, (bc != Bytecodes::_tableswitch)); |
| int oldPad = (recPad != -1) ? recPad : align(bci+1) - (bci+1); |
| if (bci > break_bci) { |
| int new_bci = bci + delta; |
| int newPad = align(new_bci+1) - (new_bci+1); |
| // Do we need to check the padding? |
| if (newPad != oldPad) { |
| if (recPad == -1) { |
| _changes->push(new ChangeSwitchPad(bci, oldPad, (bc != Bytecodes::_tableswitch))); |
| } |
| } |
| } |
| |
| // Then the rest, which depend on the kind of switch. |
| switch (bc) { |
| case Bytecodes::_tableswitch: { |
| change_jump(bci, bci +1 + oldPad, false, break_bci, delta); |
| // We cannot use the Bytecode_tableswitch abstraction, since the padding might not be correct. |
| int lo = int_at(bci + 1 + oldPad + 4 * 1); |
| int hi = int_at(bci + 1 + oldPad + 4 * 2); |
| int n = hi - lo + 1; |
| for (int k = 0; k < n; k++) { |
| change_jump(bci, bci +1 + oldPad + 4*(k+3), false, break_bci, delta); |
| } |
| // Special next-bci calculation here... |
| bci += 1 + oldPad + (n+3)*4; |
| continue; |
| } |
| case Bytecodes::_lookupswitch: |
| case Bytecodes::_fast_linearswitch: |
| case Bytecodes::_fast_binaryswitch: { |
| change_jump(bci, bci +1 + oldPad, false, break_bci, delta); |
| // We cannot use the Bytecode_lookupswitch abstraction, since the padding might not be correct. |
| int npairs = int_at(bci + 1 + oldPad + 4 * 1); |
| for (int k = 0; k < npairs; k++) { |
| change_jump(bci, bci + 1 + oldPad + 4*(2 + 2*k + 1), false, break_bci, delta); |
| } |
| /* Special next-bci calculation here... */ |
| bci += 1 + oldPad + (2 + (npairs*2))*4; |
| continue; |
| } |
| default: |
| ShouldNotReachHere(); |
| } |
| } |
| default: |
| break; |
| } |
| bci += rc_instr_len(bci); |
| } |
| } |
| |
| // The width of instruction at "pc" is changing by "delta". Adjust the |
| // exception table, if any, of "rc->mb". |
| void Relocator::adjust_exception_table(int bci, int delta) { |
| ExceptionTable table(_method()); |
| for (int index = 0; index < table.length(); index ++) { |
| if (table.start_pc(index) > bci) { |
| table.set_start_pc(index, table.start_pc(index) + delta); |
| table.set_end_pc(index, table.end_pc(index) + delta); |
| } else if (bci < table.end_pc(index)) { |
| table.set_end_pc(index, table.end_pc(index) + delta); |
| } |
| if (table.handler_pc(index) > bci) |
| table.set_handler_pc(index, table.handler_pc(index) + delta); |
| } |
| } |
| |
| |
| // The width of instruction at "bci" is changing by "delta". Adjust the line number table. |
| void Relocator::adjust_line_no_table(int bci, int delta) { |
| if (method()->has_linenumber_table()) { |
| CompressedLineNumberReadStream reader(method()->compressed_linenumber_table()); |
| CompressedLineNumberWriteStream writer(64); // plenty big for most line number tables |
| while (reader.read_pair()) { |
| int adjustment = (reader.bci() > bci) ? delta : 0; |
| writer.write_pair(reader.bci() + adjustment, reader.line()); |
| } |
| writer.write_terminator(); |
| set_compressed_line_number_table(writer.buffer()); |
| set_compressed_line_number_table_size(writer.position()); |
| } |
| } |
| |
| |
| // The width of instruction at "bci" is changing by "delta". Adjust the local variable table. |
| void Relocator::adjust_local_var_table(int bci, int delta) { |
| int localvariable_table_length = method()->localvariable_table_length(); |
| if (localvariable_table_length > 0) { |
| LocalVariableTableElement* table = method()->localvariable_table_start(); |
| for (int i = 0; i < localvariable_table_length; i++) { |
| u2 current_bci = table[i].start_bci; |
| if (current_bci > bci) { |
| table[i].start_bci = current_bci + delta; |
| } else { |
| u2 current_length = table[i].length; |
| if (current_bci + current_length > bci) { |
| table[i].length = current_length + delta; |
| } |
| } |
| } |
| } |
| } |
| |
| // Create a new array, copying the src array but adding a hole at |
| // the specified location |
| static Array<u1>* insert_hole_at(ClassLoaderData* loader_data, |
| size_t where, int hole_sz, Array<u1>* src) { |
| Thread* THREAD = Thread::current(); |
| Array<u1>* dst = |
| MetadataFactory::new_array<u1>(loader_data, src->length() + hole_sz, 0, CHECK_NULL); |
| |
| address src_addr = (address)src->adr_at(0); |
| address dst_addr = (address)dst->adr_at(0); |
| |
| memcpy(dst_addr, src_addr, where); |
| memcpy(dst_addr + where + hole_sz, |
| src_addr + where, src->length() - where); |
| return dst; |
| } |
| |
| // The width of instruction at "bci" is changing by "delta". Adjust the stack |
| // map frames. |
| void Relocator::adjust_stack_map_table(int bci, int delta) { |
| if (method()->has_stackmap_table()) { |
| Array<u1>* data = method()->stackmap_data(); |
| // The data in the array is a classfile representation of the stackmap table |
| stack_map_table* sm_table = |
| 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 likly 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; |
| } |
