diff -r fd16c54261b3 -r 489c9b5090e2 hotspot/src/share/vm/runtime/relocator.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hotspot/src/share/vm/runtime/relocator.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,647 @@ +/* + * Copyright 1997-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +# include "incls/_precompiled.incl" +# include "incls/_relocator.cpp.incl" + +#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 (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 = methodOopDesc::clone_with_new_data(method(), + code_array(), code_length(), + compressed_line_number_table(), + compressed_line_number_table_size(), + CHECK_(methodHandle())); + 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) { + typeArrayOop table = method()->exception_table(); + for (int index = 0; index < table->length(); index +=4) { + if (table->int_at(index) > bci) { + table->int_at_put(index+0, table->int_at(index+0) + delta); + table->int_at_put(index+1, table->int_at(index+1) + delta); + } else if (bci < table->int_at(index+1)) { + table->int_at_put(index+1, table->int_at(index+1) + delta); + } + if (table->int_at(index+2) > bci) + table->int_at_put(index+2, table->int_at(index+2) + 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; + } + } + } + } +} + + +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 methodOop + 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); + + // 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 goto 6 + // 3 _goto 11 + // 6 _goto_w + // 11 + 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 + 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); + } + } + return true; +}