diff -r fd16c54261b3 -r 489c9b5090e2 hotspot/src/share/vm/oops/generateOopMap.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hotspot/src/share/vm/oops/generateOopMap.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,2536 @@ +/* + * 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. + * + */ + +// +// +// Compute stack layouts for each instruction in method. +// +// Problems: +// - What to do about jsr with different types of local vars? +// Need maps that are conditional on jsr path? +// - Jsr and exceptions should be done more efficiently (the retAddr stuff) +// +// Alternative: +// - Could extend verifier to provide this information. +// For: one fewer abstract interpreter to maintain. Against: the verifier +// solves a bigger problem so slower (undesirable to force verification of +// everything?). +// +// Algorithm: +// Partition bytecodes into basic blocks +// For each basic block: store entry state (vars, stack). For instructions +// inside basic blocks we do not store any state (instead we recompute it +// from state produced by previous instruction). +// +// Perform abstract interpretation of bytecodes over this lattice: +// +// _--'#'--_ +// / / \ \ +// / / \ \ +// / | | \ +// 'r' 'v' 'p' ' ' +// \ | | / +// \ \ / / +// \ \ / / +// -- '@' -- +// +// '#' top, result of conflict merge +// 'r' reference type +// 'v' value type +// 'p' pc type for jsr/ret +// ' ' uninitialized; never occurs on operand stack in Java +// '@' bottom/unexecuted; initial state each bytecode. +// +// Basic block headers are the only merge points. We use this iteration to +// compute the information: +// +// find basic blocks; +// initialize them with uninitialized state; +// initialize first BB according to method signature; +// mark first BB changed +// while (some BB is changed) do { +// perform abstract interpration of all bytecodes in BB; +// merge exit state of BB into entry state of all successor BBs, +// noting if any of these change; +// } +// +// One additional complication is necessary. The jsr instruction pushes +// a return PC on the stack (a 'p' type in the abstract interpretation). +// To be able to process "ret" bytecodes, we keep track of these return +// PC's in a 'retAddrs' structure in abstract interpreter context (when +// processing a "ret" bytecodes, it is not sufficient to know that it gets +// an argument of the right type 'p'; we need to know which address it +// returns to). +// +// (Note this comment is borrowed form the original author of the algorithm) + +#include "incls/_precompiled.incl" +#include "incls/_generateOopMap.cpp.incl" + +// ComputeCallStack +// +// Specialization of SignatureIterator - compute the effects of a call +// +class ComputeCallStack : public SignatureIterator { + CellTypeState *_effect; + int _idx; + + void setup(); + void set(CellTypeState state) { _effect[_idx++] = state; } + int length() { return _idx; }; + + virtual void do_bool () { set(CellTypeState::value); }; + virtual void do_char () { set(CellTypeState::value); }; + virtual void do_float () { set(CellTypeState::value); }; + virtual void do_byte () { set(CellTypeState::value); }; + virtual void do_short () { set(CellTypeState::value); }; + virtual void do_int () { set(CellTypeState::value); }; + virtual void do_void () { set(CellTypeState::bottom);}; + virtual void do_object(int begin, int end) { set(CellTypeState::ref); }; + virtual void do_array (int begin, int end) { set(CellTypeState::ref); }; + + void do_double() { set(CellTypeState::value); + set(CellTypeState::value); } + void do_long () { set(CellTypeState::value); + set(CellTypeState::value); } + +public: + ComputeCallStack(symbolOop signature) : SignatureIterator(signature) {}; + + // Compute methods + int compute_for_parameters(bool is_static, CellTypeState *effect) { + _idx = 0; + _effect = effect; + + if (!is_static) + effect[_idx++] = CellTypeState::ref; + + iterate_parameters(); + + return length(); + }; + + int compute_for_returntype(CellTypeState *effect) { + _idx = 0; + _effect = effect; + iterate_returntype(); + set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works + + return length(); + } +}; + +//========================================================================================= +// ComputeEntryStack +// +// Specialization of SignatureIterator - in order to set up first stack frame +// +class ComputeEntryStack : public SignatureIterator { + CellTypeState *_effect; + int _idx; + + void setup(); + void set(CellTypeState state) { _effect[_idx++] = state; } + int length() { return _idx; }; + + virtual void do_bool () { set(CellTypeState::value); }; + virtual void do_char () { set(CellTypeState::value); }; + virtual void do_float () { set(CellTypeState::value); }; + virtual void do_byte () { set(CellTypeState::value); }; + virtual void do_short () { set(CellTypeState::value); }; + virtual void do_int () { set(CellTypeState::value); }; + virtual void do_void () { set(CellTypeState::bottom);}; + virtual void do_object(int begin, int end) { set(CellTypeState::make_slot_ref(_idx)); } + virtual void do_array (int begin, int end) { set(CellTypeState::make_slot_ref(_idx)); } + + void do_double() { set(CellTypeState::value); + set(CellTypeState::value); } + void do_long () { set(CellTypeState::value); + set(CellTypeState::value); } + +public: + ComputeEntryStack(symbolOop signature) : SignatureIterator(signature) {}; + + // Compute methods + int compute_for_parameters(bool is_static, CellTypeState *effect) { + _idx = 0; + _effect = effect; + + if (!is_static) + effect[_idx++] = CellTypeState::make_slot_ref(0); + + iterate_parameters(); + + return length(); + }; + + int compute_for_returntype(CellTypeState *effect) { + _idx = 0; + _effect = effect; + iterate_returntype(); + set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works + + return length(); + } +}; + +//===================================================================================== +// +// Implementation of RetTable/RetTableEntry +// +// Contains function to itereate through all bytecodes +// and find all return entry points +// +int RetTable::_init_nof_entries = 10; +int RetTableEntry::_init_nof_jsrs = 5; + +void RetTableEntry::add_delta(int bci, int delta) { + if (_target_bci > bci) _target_bci += delta; + + for (int k = 0; k < _jsrs->length(); k++) { + int jsr = _jsrs->at(k); + if (jsr > bci) _jsrs->at_put(k, jsr+delta); + } +} + +void RetTable::compute_ret_table(methodHandle method) { + BytecodeStream i(method); + Bytecodes::Code bytecode; + + while( (bytecode = i.next()) >= 0) { + switch (bytecode) { + case Bytecodes::_jsr: + add_jsr(i.next_bci(), i.dest()); + break; + case Bytecodes::_jsr_w: + add_jsr(i.next_bci(), i.dest_w()); + break; + } + } +} + +void RetTable::add_jsr(int return_bci, int target_bci) { + RetTableEntry* entry = _first; + + // Scan table for entry + for (;entry && entry->target_bci() != target_bci; entry = entry->next()); + + if (!entry) { + // Allocate new entry and put in list + entry = new RetTableEntry(target_bci, _first); + _first = entry; + } + + // Now "entry" is set. Make sure that the entry is initialized + // and has room for the new jsr. + entry->add_jsr(return_bci); +} + +RetTableEntry* RetTable::find_jsrs_for_target(int targBci) { + RetTableEntry *cur = _first; + + while(cur) { + assert(cur->target_bci() != -1, "sanity check"); + if (cur->target_bci() == targBci) return cur; + cur = cur->next(); + } + ShouldNotReachHere(); + return NULL; +} + +// The instruction at bci is changing size by "delta". Update the return map. +void RetTable::update_ret_table(int bci, int delta) { + RetTableEntry *cur = _first; + while(cur) { + cur->add_delta(bci, delta); + cur = cur->next(); + } +} + +// +// Celltype state +// + +CellTypeState CellTypeState::bottom = CellTypeState::make_bottom(); +CellTypeState CellTypeState::uninit = CellTypeState::make_any(uninit_value); +CellTypeState CellTypeState::ref = CellTypeState::make_any(ref_conflict); +CellTypeState CellTypeState::value = CellTypeState::make_any(val_value); +CellTypeState CellTypeState::refUninit = CellTypeState::make_any(ref_conflict | uninit_value); +CellTypeState CellTypeState::top = CellTypeState::make_top(); +CellTypeState CellTypeState::addr = CellTypeState::make_any(addr_conflict); + +// Commonly used constants +static CellTypeState epsilonCTS[1] = { CellTypeState::bottom }; +static CellTypeState refCTS = CellTypeState::ref; +static CellTypeState valCTS = CellTypeState::value; +static CellTypeState vCTS[2] = { CellTypeState::value, CellTypeState::bottom }; +static CellTypeState rCTS[2] = { CellTypeState::ref, CellTypeState::bottom }; +static CellTypeState rrCTS[3] = { CellTypeState::ref, CellTypeState::ref, CellTypeState::bottom }; +static CellTypeState vrCTS[3] = { CellTypeState::value, CellTypeState::ref, CellTypeState::bottom }; +static CellTypeState vvCTS[3] = { CellTypeState::value, CellTypeState::value, CellTypeState::bottom }; +static CellTypeState rvrCTS[4] = { CellTypeState::ref, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom }; +static CellTypeState vvrCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom }; +static CellTypeState vvvCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom }; +static CellTypeState vvvrCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom }; +static CellTypeState vvvvCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom }; + +char CellTypeState::to_char() const { + if (can_be_reference()) { + if (can_be_value() || can_be_address()) + return '#'; // Conflict that needs to be rewritten + else + return 'r'; + } else if (can_be_value()) + return 'v'; + else if (can_be_address()) + return 'p'; + else if (can_be_uninit()) + return ' '; + else + return '@'; +} + + +// Print a detailed CellTypeState. Indicate all bits that are set. If +// the CellTypeState represents an address or a reference, print the +// value of the additional information. +void CellTypeState::print(outputStream *os) { + if (can_be_address()) { + os->print("(p"); + } else { + os->print("( "); + } + if (can_be_reference()) { + os->print("r"); + } else { + os->print(" "); + } + if (can_be_value()) { + os->print("v"); + } else { + os->print(" "); + } + if (can_be_uninit()) { + os->print("u|"); + } else { + os->print(" |"); + } + if (is_info_top()) { + os->print("Top)"); + } else if (is_info_bottom()) { + os->print("Bot)"); + } else { + if (is_reference()) { + int info = get_info(); + int data = info & ~(ref_not_lock_bit | ref_slot_bit); + if (info & ref_not_lock_bit) { + // Not a monitor lock reference. + if (info & ref_slot_bit) { + // slot + os->print("slot%d)", data); + } else { + // line + os->print("line%d)", data); + } + } else { + // lock + os->print("lock%d)", data); + } + } else { + os->print("%d)", get_info()); + } + } +} + +// +// Basicblock handling methods +// + +void GenerateOopMap ::initialize_bb() { + _gc_points = 0; + _bb_count = 0; + int size = binsToHold(method()->code_size()); + _bb_hdr_bits = NEW_RESOURCE_ARRAY(uintptr_t,size); + memset(_bb_hdr_bits, 0, size*sizeof(uintptr_t)); +} + +void GenerateOopMap ::set_bbmark_bit(int bci) { + int idx = bci >> LogBitsPerWord; + uintptr_t bit = (uintptr_t)1 << (bci & (BitsPerWord-1)); + _bb_hdr_bits[idx] |= bit; +} + +void GenerateOopMap ::clear_bbmark_bit(int bci) { + int idx = bci >> LogBitsPerWord; + uintptr_t bit = (uintptr_t)1 << (bci & (BitsPerWord-1)); + _bb_hdr_bits[idx] &= (~bit); +} + +void GenerateOopMap::bb_mark_fct(GenerateOopMap *c, int bci, int *data) { + assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds"); + if (c->is_bb_header(bci)) + return; + + if (TraceNewOopMapGeneration) { + tty->print_cr("Basicblock#%d begins at: %d", c->_bb_count, bci); + } + c->set_bbmark_bit(bci); + c->_bb_count++; +} + + +void GenerateOopMap::mark_bbheaders_and_count_gc_points() { + initialize_bb(); + + bool fellThrough = false; // False to get first BB marked. + + // First mark all exception handlers as start of a basic-block + typeArrayOop excps = method()->exception_table(); + for(int i = 0; i < excps->length(); i += 4) { + int handler_pc_idx = i+2; + bb_mark_fct(this, excps->int_at(handler_pc_idx), NULL); + } + + // Then iterate through the code + BytecodeStream bcs(_method); + Bytecodes::Code bytecode; + + while( (bytecode = bcs.next()) >= 0) { + int bci = bcs.bci(); + + if (!fellThrough) + bb_mark_fct(this, bci, NULL); + + fellThrough = jump_targets_do(&bcs, &GenerateOopMap::bb_mark_fct, NULL); + + /* We will also mark successors of jsr's as basic block headers. */ + switch (bytecode) { + case Bytecodes::_jsr: + assert(!fellThrough, "should not happen"); + bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL); + break; + case Bytecodes::_jsr_w: + assert(!fellThrough, "should not happen"); + bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL); + break; + } + + if (possible_gc_point(&bcs)) + _gc_points++; + } +} + +void GenerateOopMap::reachable_basicblock(GenerateOopMap *c, int bci, int *data) { + assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds"); + BasicBlock* bb = c->get_basic_block_at(bci); + if (bb->is_dead()) { + bb->mark_as_alive(); + *data = 1; // Mark basicblock as changed + } +} + + +void GenerateOopMap::mark_reachable_code() { + int change = 1; // int to get function pointers to work + + // Mark entry basic block as alive and all exception handlers + _basic_blocks[0].mark_as_alive(); + typeArrayOop excps = method()->exception_table(); + for(int i = 0; i < excps->length(); i += 4) { + int handler_pc_idx = i+2; + BasicBlock *bb = get_basic_block_at(excps->int_at(handler_pc_idx)); + // If block is not already alive (due to multiple exception handlers to same bb), then + // make it alive + if (bb->is_dead()) bb->mark_as_alive(); + } + + BytecodeStream bcs(_method); + + // Iterate through all basic blocks until we reach a fixpoint + while (change) { + change = 0; + + for (int i = 0; i < _bb_count; i++) { + BasicBlock *bb = &_basic_blocks[i]; + if (bb->is_alive()) { + // Position bytecodestream at last bytecode in basicblock + bcs.set_start(bb->_end_bci); + bcs.next(); + Bytecodes::Code bytecode = bcs.code(); + int bci = bcs.bci(); + assert(bci == bb->_end_bci, "wrong bci"); + + bool fell_through = jump_targets_do(&bcs, &GenerateOopMap::reachable_basicblock, &change); + + // We will also mark successors of jsr's as alive. + switch (bytecode) { + case Bytecodes::_jsr: + case Bytecodes::_jsr_w: + assert(!fell_through, "should not happen"); + reachable_basicblock(this, bci + Bytecodes::length_for(bytecode), &change); + break; + } + if (fell_through) { + // Mark successor as alive + if (bb[1].is_dead()) { + bb[1].mark_as_alive(); + change = 1; + } + } + } + } + } +} + +/* If the current instruction in "c" has no effect on control flow, + returns "true". Otherwise, calls "jmpFct" one or more times, with + "c", an appropriate "pcDelta", and "data" as arguments, then + returns "false". There is one exception: if the current + instruction is a "ret", returns "false" without calling "jmpFct". + Arrangements for tracking the control flow of a "ret" must be made + externally. */ +bool GenerateOopMap::jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int *data) { + int bci = bcs->bci(); + + switch (bcs->code()) { + 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: + (*jmpFct)(this, bcs->dest(), data); + (*jmpFct)(this, bci + 3, data); + break; + + case Bytecodes::_goto: + (*jmpFct)(this, bcs->dest(), data); + break; + case Bytecodes::_goto_w: + (*jmpFct)(this, bcs->dest_w(), data); + break; + case Bytecodes::_tableswitch: + { Bytecode_tableswitch *tableswitch = Bytecode_tableswitch_at(bcs->bcp()); + int len = tableswitch->length(); + + (*jmpFct)(this, bci + tableswitch->default_offset(), data); /* Default. jump address */ + while (--len >= 0) { + (*jmpFct)(this, bci + tableswitch->dest_offset_at(len), data); + } + break; + } + + case Bytecodes::_lookupswitch: + { Bytecode_lookupswitch *lookupswitch = Bytecode_lookupswitch_at(bcs->bcp()); + int npairs = lookupswitch->number_of_pairs(); + (*jmpFct)(this, bci + lookupswitch->default_offset(), data); /* Default. */ + while(--npairs >= 0) { + LookupswitchPair *pair = lookupswitch->pair_at(npairs); + (*jmpFct)(this, bci + pair->offset(), data); + } + break; + } + case Bytecodes::_jsr: + assert(bcs->is_wide()==false, "sanity check"); + (*jmpFct)(this, bcs->dest(), data); + + + + break; + case Bytecodes::_jsr_w: + (*jmpFct)(this, bcs->dest_w(), data); + break; + case Bytecodes::_wide: + ShouldNotReachHere(); + return true; + break; + case Bytecodes::_athrow: + case Bytecodes::_ireturn: + case Bytecodes::_lreturn: + case Bytecodes::_freturn: + case Bytecodes::_dreturn: + case Bytecodes::_areturn: + case Bytecodes::_return: + case Bytecodes::_ret: + break; + default: + return true; + } + return false; +} + +/* Requires "pc" to be the head of a basic block; returns that basic + block. */ +BasicBlock *GenerateOopMap::get_basic_block_at(int bci) const { + BasicBlock* bb = get_basic_block_containing(bci); + assert(bb->_bci == bci, "should have found BB"); + return bb; +} + +// Requires "pc" to be the start of an instruction; returns the basic +// block containing that instruction. */ +BasicBlock *GenerateOopMap::get_basic_block_containing(int bci) const { + BasicBlock *bbs = _basic_blocks; + int lo = 0, hi = _bb_count - 1; + + while (lo <= hi) { + int m = (lo + hi) / 2; + int mbci = bbs[m]._bci; + int nbci; + + if ( m == _bb_count-1) { + assert( bci >= mbci && bci < method()->code_size(), "sanity check failed"); + return bbs+m; + } else { + nbci = bbs[m+1]._bci; + } + + if ( mbci <= bci && bci < nbci) { + return bbs+m; + } else if (mbci < bci) { + lo = m + 1; + } else { + assert(mbci > bci, "sanity check"); + hi = m - 1; + } + } + + fatal("should have found BB"); + return NULL; +} + +void GenerateOopMap::restore_state(BasicBlock *bb) +{ + memcpy(_state, bb->_state, _state_len*sizeof(CellTypeState)); + _stack_top = bb->_stack_top; + _monitor_top = bb->_monitor_top; +} + +int GenerateOopMap::next_bb_start_pc(BasicBlock *bb) { + int bbNum = bb - _basic_blocks + 1; + if (bbNum == _bb_count) + return method()->code_size(); + + return _basic_blocks[bbNum]._bci; +} + +// +// CellType handling methods +// + +void GenerateOopMap::init_state() { + _state_len = _max_locals + _max_stack + _max_monitors; + _state = NEW_RESOURCE_ARRAY(CellTypeState, _state_len); + memset(_state, 0, _state_len * sizeof(CellTypeState)); + _state_vec_buf = NEW_RESOURCE_ARRAY(char, MAX3(_max_locals, _max_stack, _max_monitors) + 1/*for null terminator char */); +} + +void GenerateOopMap::make_context_uninitialized() { + CellTypeState* vs = vars(); + + for (int i = 0; i < _max_locals; i++) + vs[i] = CellTypeState::uninit; + + _stack_top = 0; + _monitor_top = 0; +} + +int GenerateOopMap::methodsig_to_effect(symbolOop signature, bool is_static, CellTypeState* effect) { + ComputeEntryStack ces(signature); + return ces.compute_for_parameters(is_static, effect); +} + +// Return result of merging cts1 and cts2. +CellTypeState CellTypeState::merge(CellTypeState cts, int slot) const { + CellTypeState result; + + assert(!is_bottom() && !cts.is_bottom(), + "merge of bottom values is handled elsewhere"); + + result._state = _state | cts._state; + + // If the top bit is set, we don't need to do any more work. + if (!result.is_info_top()) { + assert((result.can_be_address() || result.can_be_reference()), + "only addresses and references have non-top info"); + + if (!equal(cts)) { + // The two values being merged are different. Raise to top. + if (result.is_reference()) { + result = CellTypeState::make_slot_ref(slot); + } else { + result._state |= info_conflict; + } + } + } + assert(result.is_valid_state(), "checking that CTS merge maintains legal state"); + + return result; +} + +// Merge the variable state for locals and stack from cts into bbts. +bool GenerateOopMap::merge_local_state_vectors(CellTypeState* cts, + CellTypeState* bbts) { + int i; + int len = _max_locals + _stack_top; + bool change = false; + + for (i = len - 1; i >= 0; i--) { + CellTypeState v = cts[i].merge(bbts[i], i); + change = change || !v.equal(bbts[i]); + bbts[i] = v; + } + + return change; +} + +// Merge the monitor stack state from cts into bbts. +bool GenerateOopMap::merge_monitor_state_vectors(CellTypeState* cts, + CellTypeState* bbts) { + bool change = false; + if (_max_monitors > 0 && _monitor_top != bad_monitors) { + // If there are no monitors in the program, or there has been + // a monitor matching error before this point in the program, + // then we do not merge in the monitor state. + + int base = _max_locals + _max_stack; + int len = base + _monitor_top; + for (int i = len - 1; i >= base; i--) { + CellTypeState v = cts[i].merge(bbts[i], i); + + // Can we prove that, when there has been a change, it will already + // have been detected at this point? That would make this equal + // check here unnecessary. + change = change || !v.equal(bbts[i]); + bbts[i] = v; + } + } + + return change; +} + +void GenerateOopMap::copy_state(CellTypeState *dst, CellTypeState *src) { + int len = _max_locals + _stack_top; + for (int i = 0; i < len; i++) { + if (src[i].is_nonlock_reference()) { + dst[i] = CellTypeState::make_slot_ref(i); + } else { + dst[i] = src[i]; + } + } + if (_max_monitors > 0 && _monitor_top != bad_monitors) { + int base = _max_locals + _max_stack; + len = base + _monitor_top; + for (int i = base; i < len; i++) { + dst[i] = src[i]; + } + } +} + + +// Merge the states for the current block and the next. As long as a +// block is reachable the locals and stack must be merged. If the +// stack heights don't match then this is a verification error and +// it's impossible to interpret the code. Simultaneously monitor +// states are being check to see if they nest statically. If monitor +// depths match up then their states are merged. Otherwise the +// mismatch is simply recorded and interpretation continues since +// monitor matching is purely informational and doesn't say anything +// about the correctness of the code. +void GenerateOopMap::merge_state_into_bb(BasicBlock *bb) { + assert(bb->is_alive(), "merging state into a dead basicblock"); + + if (_stack_top == bb->_stack_top) { + // always merge local state even if monitors don't match. + if (merge_local_state_vectors(_state, bb->_state)) { + bb->set_changed(true); + } + if (_monitor_top == bb->_monitor_top) { + // monitors still match so continue merging monitor states. + if (merge_monitor_state_vectors(_state, bb->_state)) { + bb->set_changed(true); + } + } else { + if (TraceMonitorMismatch) { + report_monitor_mismatch("monitor stack height merge conflict"); + } + // When the monitor stacks are not matched, we set _monitor_top to + // bad_monitors. This signals that, from here on, the monitor stack cannot + // be trusted. In particular, monitorexit bytecodes may throw + // exceptions. We mark this block as changed so that the change + // propagates properly. + bb->_monitor_top = bad_monitors; + bb->set_changed(true); + _monitor_safe = false; + } + } else if (!bb->is_reachable()) { + // First time we look at this BB + copy_state(bb->_state, _state); + bb->_stack_top = _stack_top; + bb->_monitor_top = _monitor_top; + bb->set_changed(true); + } else { + verify_error("stack height conflict: %d vs. %d", _stack_top, bb->_stack_top); + } +} + +void GenerateOopMap::merge_state(GenerateOopMap *gom, int bci, int* data) { + gom->merge_state_into_bb(gom->get_basic_block_at(bci)); +} + +void GenerateOopMap::set_var(int localNo, CellTypeState cts) { + assert(cts.is_reference() || cts.is_value() || cts.is_address(), + "wrong celltypestate"); + if (localNo < 0 || localNo > _max_locals) { + verify_error("variable write error: r%d", localNo); + return; + } + vars()[localNo] = cts; +} + +CellTypeState GenerateOopMap::get_var(int localNo) { + assert(localNo < _max_locals + _nof_refval_conflicts, "variable read error") + if (localNo < 0 || localNo > _max_locals) { + verify_error("variable read error: r%d", localNo); + return valCTS; // just to pick something; + } + return vars()[localNo]; +} + +CellTypeState GenerateOopMap::pop() { + if ( _stack_top <= 0) { + verify_error("stack underflow"); + return valCTS; // just to pick something + } + return stack()[--_stack_top]; +} + +void GenerateOopMap::push(CellTypeState cts) { + if ( _stack_top >= _max_stack) { + verify_error("stack overflow"); + return; + } + stack()[_stack_top++] = cts; +} + +CellTypeState GenerateOopMap::monitor_pop() { + assert(_monitor_top != bad_monitors, "monitor_pop called on error monitor stack"); + if (_monitor_top == 0) { + // We have detected a pop of an empty monitor stack. + _monitor_safe = false; + _monitor_top = bad_monitors; + + if (TraceMonitorMismatch) { + report_monitor_mismatch("monitor stack underflow"); + } + return CellTypeState::ref; // just to keep the analysis going. + } + return monitors()[--_monitor_top]; +} + +void GenerateOopMap::monitor_push(CellTypeState cts) { + assert(_monitor_top != bad_monitors, "monitor_push called on error monitor stack"); + if (_monitor_top >= _max_monitors) { + // Some monitorenter is being executed more than once. + // This means that the monitor stack cannot be simulated. + _monitor_safe = false; + _monitor_top = bad_monitors; + + if (TraceMonitorMismatch) { + report_monitor_mismatch("monitor stack overflow"); + } + return; + } + monitors()[_monitor_top++] = cts; +} + +// +// Interpretation handling methods +// + +void GenerateOopMap::do_interpretation() +{ + // "i" is just for debugging, so we can detect cases where this loop is + // iterated more than once. + int i = 0; + do { +#ifndef PRODUCT + if (TraceNewOopMapGeneration) { + tty->print("\n\nIteration #%d of do_interpretation loop, method:\n", i); + method()->print_name(tty); + tty->print("\n\n"); + } +#endif + _conflict = false; + _monitor_safe = true; + // init_state is now called from init_basic_blocks. The length of a + // state vector cannot be determined until we have made a pass through + // the bytecodes counting the possible monitor entries. + if (!_got_error) init_basic_blocks(); + if (!_got_error) setup_method_entry_state(); + if (!_got_error) interp_all(); + if (!_got_error) rewrite_refval_conflicts(); + i++; + } while (_conflict && !_got_error); +} + +void GenerateOopMap::init_basic_blocks() { + // Note: Could consider reserving only the needed space for each BB's state + // (entry stack may not be of maximal height for every basic block). + // But cumbersome since we don't know the stack heights yet. (Nor the + // monitor stack heights...) + + _basic_blocks = NEW_RESOURCE_ARRAY(BasicBlock, _bb_count); + + // Make a pass through the bytecodes. Count the number of monitorenters. + // This can be used an upper bound on the monitor stack depth in programs + // which obey stack discipline with their monitor usage. Initialize the + // known information about basic blocks. + BytecodeStream j(_method); + Bytecodes::Code bytecode; + + int bbNo = 0; + int monitor_count = 0; + int prev_bci = -1; + while( (bytecode = j.next()) >= 0) { + if (j.code() == Bytecodes::_monitorenter) { + monitor_count++; + } + + int bci = j.bci(); + if (is_bb_header(bci)) { + // Initialize the basicblock structure + BasicBlock *bb = _basic_blocks + bbNo; + bb->_bci = bci; + bb->_max_locals = _max_locals; + bb->_max_stack = _max_stack; + bb->set_changed(false); + bb->_stack_top = BasicBlock::_dead_basic_block; // Initialize all basicblocks are dead. + bb->_monitor_top = bad_monitors; + + if (bbNo > 0) { + _basic_blocks[bbNo - 1]._end_bci = prev_bci; + } + + bbNo++; + } + // Remember prevous bci. + prev_bci = bci; + } + // Set + _basic_blocks[bbNo-1]._end_bci = prev_bci; + + + _max_monitors = monitor_count; + + // Now that we have a bound on the depth of the monitor stack, we can + // initialize the CellTypeState-related information. + init_state(); + + // We allocate space for all state-vectors for all basicblocks in one huge chuck. + // Then in the next part of the code, we set a pointer in each _basic_block that + // points to each piece. + CellTypeState *basicBlockState = NEW_RESOURCE_ARRAY(CellTypeState, bbNo * _state_len); + memset(basicBlockState, 0, bbNo * _state_len * sizeof(CellTypeState)); + + // Make a pass over the basicblocks and assign their state vectors. + for (int blockNum=0; blockNum < bbNo; blockNum++) { + BasicBlock *bb = _basic_blocks + blockNum; + bb->_state = basicBlockState + blockNum * _state_len; + +#ifdef ASSERT + if (blockNum + 1 < bbNo) { + address bcp = _method->bcp_from(bb->_end_bci); + int bc_len = Bytecodes::java_length_at(bcp); + assert(bb->_end_bci + bc_len == bb[1]._bci, "unmatched bci info in basicblock"); + } +#endif + } +#ifdef ASSERT + { BasicBlock *bb = &_basic_blocks[bbNo-1]; + address bcp = _method->bcp_from(bb->_end_bci); + int bc_len = Bytecodes::java_length_at(bcp); + assert(bb->_end_bci + bc_len == _method->code_size(), "wrong end bci"); + } +#endif + + // Check that the correct number of basicblocks was found + if (bbNo !=_bb_count) { + if (bbNo < _bb_count) { + verify_error("jump into the middle of instruction?"); + return; + } else { + verify_error("extra basic blocks - should not happen?"); + return; + } + } + + // Mark all alive blocks + mark_reachable_code(); +} + +void GenerateOopMap::setup_method_entry_state() { + + // Initialize all locals to 'uninit' and set stack-height to 0 + make_context_uninitialized(); + + // Initialize CellState type of arguments + methodsig_to_effect(method()->signature(), method()->is_static(), vars()); + + // If some references must be pre-assigned to null, then set that up + initialize_vars(); + + // This is the start state + merge_state_into_bb(&_basic_blocks[0]); + + assert(_basic_blocks[0].changed(), "we are not getting off the ground"); +} + +// The instruction at bci is changing size by "delta". Update the basic blocks. +void GenerateOopMap::update_basic_blocks(int bci, int delta, + int new_method_size) { + assert(new_method_size >= method()->code_size() + delta, + "new method size is too small"); + int newWords = binsToHold(new_method_size); + + uintptr_t * new_bb_hdr_bits = NEW_RESOURCE_ARRAY(uintptr_t, newWords); + + BitMap bb_bits(new_bb_hdr_bits, new_method_size); + bb_bits.clear(); + + for(int k = 0; k < _bb_count; k++) { + if (_basic_blocks[k]._bci > bci) { + _basic_blocks[k]._bci += delta; + _basic_blocks[k]._end_bci += delta; + } + bb_bits.at_put(_basic_blocks[k]._bci, true); + } + _bb_hdr_bits = new_bb_hdr_bits ; +} + +// +// Initvars handling +// + +void GenerateOopMap::initialize_vars() { + for (int k = 0; k < _init_vars->length(); k++) + _state[_init_vars->at(k)] = CellTypeState::make_slot_ref(k); +} + +void GenerateOopMap::add_to_ref_init_set(int localNo) { + + if (TraceNewOopMapGeneration) + tty->print_cr("Added init vars: %d", localNo); + + // Is it already in the set? + if (_init_vars->contains(localNo) ) + return; + + _init_vars->append(localNo); +} + +// +// Interpreration code +// + +void GenerateOopMap::interp_all() { + bool change = true; + + while (change && !_got_error) { + change = false; + for (int i = 0; i < _bb_count && !_got_error; i++) { + BasicBlock *bb = &_basic_blocks[i]; + if (bb->changed()) { + if (_got_error) return; + change = true; + bb->set_changed(false); + interp_bb(bb); + } + } + } +} + +void GenerateOopMap::interp_bb(BasicBlock *bb) { + + // We do not want to do anything in case the basic-block has not been initialized. This + // will happen in the case where there is dead-code hang around in a method. + assert(bb->is_reachable(), "should be reachable or deadcode exist"); + restore_state(bb); + + BytecodeStream itr(_method); + + // Set iterator interval to be the current basicblock + int lim_bci = next_bb_start_pc(bb); + itr.set_interval(bb->_bci, lim_bci); + assert(lim_bci != bb->_bci, "must be at least one instruction in a basicblock"); + itr.next(); // read first instruction + + // Iterates through all bytecodes except the last in a basic block. + // We handle the last one special, since there is controlflow change. + while(itr.next_bci() < lim_bci && !_got_error) { + if (_has_exceptions || _monitor_top != 0) { + // We do not need to interpret the results of exceptional + // continuation from this instruction when the method has no + // exception handlers and the monitor stack is currently + // empty. + do_exception_edge(&itr); + } + interp1(&itr); + itr.next(); + } + + // Handle last instruction. + if (!_got_error) { + assert(itr.next_bci() == lim_bci, "must point to end"); + if (_has_exceptions || _monitor_top != 0) { + do_exception_edge(&itr); + } + interp1(&itr); + + bool fall_through = jump_targets_do(&itr, GenerateOopMap::merge_state, NULL); + if (_got_error) return; + + if (itr.code() == Bytecodes::_ret) { + assert(!fall_through, "cannot be set if ret instruction"); + // Automatically handles 'wide' ret indicies + ret_jump_targets_do(&itr, GenerateOopMap::merge_state, itr.get_index(), NULL); + } else if (fall_through) { + // Hit end of BB, but the instr. was a fall-through instruction, + // so perform transition as if the BB ended in a "jump". + if (lim_bci != bb[1]._bci) { + verify_error("bytecodes fell through last instruction"); + return; + } + merge_state_into_bb(bb + 1); + } + } +} + +void GenerateOopMap::do_exception_edge(BytecodeStream* itr) { + // Only check exception edge, if bytecode can trap + if (!Bytecodes::can_trap(itr->code())) return; + switch (itr->code()) { + case Bytecodes::_aload_0: + // These bytecodes can trap for rewriting. We need to assume that + // they do not throw exceptions to make the monitor analysis work. + return; + + case Bytecodes::_ireturn: + case Bytecodes::_lreturn: + case Bytecodes::_freturn: + case Bytecodes::_dreturn: + case Bytecodes::_areturn: + case Bytecodes::_return: + // If the monitor stack height is not zero when we leave the method, + // then we are either exiting with a non-empty stack or we have + // found monitor trouble earlier in our analysis. In either case, + // assume an exception could be taken here. + if (_monitor_top == 0) { + return; + } + break; + + case Bytecodes::_monitorexit: + // If the monitor stack height is bad_monitors, then we have detected a + // monitor matching problem earlier in the analysis. If the + // monitor stack height is 0, we are about to pop a monitor + // off of an empty stack. In either case, the bytecode + // could throw an exception. + if (_monitor_top != bad_monitors && _monitor_top != 0) { + return; + } + break; + } + + if (_has_exceptions) { + int bci = itr->bci(); + typeArrayOop exct = method()->exception_table(); + for(int i = 0; i< exct->length(); i+=4) { + int start_pc = exct->int_at(i); + int end_pc = exct->int_at(i+1); + int handler_pc = exct->int_at(i+2); + int catch_type = exct->int_at(i+3); + + if (start_pc <= bci && bci < end_pc) { + BasicBlock *excBB = get_basic_block_at(handler_pc); + CellTypeState *excStk = excBB->stack(); + CellTypeState *cOpStck = stack(); + CellTypeState cOpStck_0 = cOpStck[0]; + int cOpStackTop = _stack_top; + + // Exception stacks are always the same. + assert(method()->max_stack() > 0, "sanity check"); + + // We remembered the size and first element of "cOpStck" + // above; now we temporarily set them to the appropriate + // values for an exception handler. */ + cOpStck[0] = CellTypeState::make_slot_ref(_max_locals); + _stack_top = 1; + + merge_state_into_bb(excBB); + + // Now undo the temporary change. + cOpStck[0] = cOpStck_0; + _stack_top = cOpStackTop; + + // If this is a "catch all" handler, then we do not need to + // consider any additional handlers. + if (catch_type == 0) { + return; + } + } + } + } + + // It is possible that none of the exception handlers would have caught + // the exception. In this case, we will exit the method. We must + // ensure that the monitor stack is empty in this case. + if (_monitor_top == 0) { + return; + } + + // We pessimistically assume that this exception can escape the + // method. (It is possible that it will always be caught, but + // we don't care to analyse the types of the catch clauses.) + + // We don't set _monitor_top to bad_monitors because there are no successors + // to this exceptional exit. + + if (TraceMonitorMismatch && _monitor_safe) { + // We check _monitor_safe so that we only report the first mismatched + // exceptional exit. + report_monitor_mismatch("non-empty monitor stack at exceptional exit"); + } + _monitor_safe = false; + +} + +void GenerateOopMap::report_monitor_mismatch(const char *msg) { +#ifndef PRODUCT + tty->print(" Monitor mismatch in method "); + method()->print_short_name(tty); + tty->print_cr(": %s", msg); +#endif +} + +void GenerateOopMap::print_states(outputStream *os, + CellTypeState* vec, int num) { + for (int i = 0; i < num; i++) { + vec[i].print(tty); + } +} + +// Print the state values at the current bytecode. +void GenerateOopMap::print_current_state(outputStream *os, + BytecodeStream *currentBC, + bool detailed) { + + if (detailed) { + os->print(" %4d vars = ", currentBC->bci()); + print_states(os, vars(), _max_locals); + os->print(" %s", Bytecodes::name(currentBC->code())); + switch(currentBC->code()) { + case Bytecodes::_invokevirtual: + case Bytecodes::_invokespecial: + case Bytecodes::_invokestatic: + case Bytecodes::_invokeinterface: + int idx = currentBC->get_index_big(); + constantPoolOop cp = method()->constants(); + int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx); + int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx); + symbolOop signature = cp->symbol_at(signatureIdx); + os->print("%s", signature->as_C_string()); + } + os->cr(); + os->print(" stack = "); + print_states(os, stack(), _stack_top); + os->cr(); + if (_monitor_top != bad_monitors) { + os->print(" monitors = "); + print_states(os, monitors(), _monitor_top); + } else { + os->print(" [bad monitor stack]"); + } + os->cr(); + } else { + os->print(" %4d vars = '%s' ", currentBC->bci(), state_vec_to_string(vars(), _max_locals)); + os->print(" stack = '%s' ", state_vec_to_string(stack(), _stack_top)); + if (_monitor_top != bad_monitors) { + os->print(" monitors = '%s' \t%s", state_vec_to_string(monitors(), _monitor_top), Bytecodes::name(currentBC->code())); + } else { + os->print(" [bad monitor stack]"); + } + switch(currentBC->code()) { + case Bytecodes::_invokevirtual: + case Bytecodes::_invokespecial: + case Bytecodes::_invokestatic: + case Bytecodes::_invokeinterface: + int idx = currentBC->get_index_big(); + constantPoolOop cp = method()->constants(); + int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx); + int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx); + symbolOop signature = cp->symbol_at(signatureIdx); + os->print("%s", signature->as_C_string()); + } + os->cr(); + } +} + +// Sets the current state to be the state after executing the +// current instruction, starting in the current state. +void GenerateOopMap::interp1(BytecodeStream *itr) { + if (TraceNewOopMapGeneration) { + print_current_state(tty, itr, TraceNewOopMapGenerationDetailed); + } + + // Should we report the results? Result is reported *before* the instruction at the current bci is executed. + // However, not for calls. For calls we do not want to include the arguments, so we postpone the reporting until + // they have been popped (in method ppl). + if (_report_result == true) { + switch(itr->code()) { + case Bytecodes::_invokevirtual: + case Bytecodes::_invokespecial: + case Bytecodes::_invokestatic: + case Bytecodes::_invokeinterface: + _itr_send = itr; + _report_result_for_send = true; + break; + default: + fill_stackmap_for_opcodes(itr, vars(), stack(), _stack_top); + break; + } + } + + // abstract interpretation of current opcode + switch(itr->code()) { + case Bytecodes::_nop: break; + case Bytecodes::_goto: break; + case Bytecodes::_goto_w: break; + case Bytecodes::_iinc: break; + case Bytecodes::_return: do_return_monitor_check(); + break; + + case Bytecodes::_aconst_null: + case Bytecodes::_new: ppush1(CellTypeState::make_line_ref(itr->bci())); + break; + + case Bytecodes::_iconst_m1: + case Bytecodes::_iconst_0: + case Bytecodes::_iconst_1: + case Bytecodes::_iconst_2: + case Bytecodes::_iconst_3: + case Bytecodes::_iconst_4: + case Bytecodes::_iconst_5: + case Bytecodes::_fconst_0: + case Bytecodes::_fconst_1: + case Bytecodes::_fconst_2: + case Bytecodes::_bipush: + case Bytecodes::_sipush: ppush1(valCTS); break; + + case Bytecodes::_lconst_0: + case Bytecodes::_lconst_1: + case Bytecodes::_dconst_0: + case Bytecodes::_dconst_1: ppush(vvCTS); break; + + case Bytecodes::_ldc2_w: ppush(vvCTS); break; + + case Bytecodes::_ldc: do_ldc(itr->get_index(), itr->bci()); break; + case Bytecodes::_ldc_w: do_ldc(itr->get_index_big(), itr->bci());break; + + case Bytecodes::_iload: + case Bytecodes::_fload: ppload(vCTS, itr->get_index()); break; + + case Bytecodes::_lload: + case Bytecodes::_dload: ppload(vvCTS,itr->get_index()); break; + + case Bytecodes::_aload: ppload(rCTS, itr->get_index()); break; + + case Bytecodes::_iload_0: + case Bytecodes::_fload_0: ppload(vCTS, 0); break; + case Bytecodes::_iload_1: + case Bytecodes::_fload_1: ppload(vCTS, 1); break; + case Bytecodes::_iload_2: + case Bytecodes::_fload_2: ppload(vCTS, 2); break; + case Bytecodes::_iload_3: + case Bytecodes::_fload_3: ppload(vCTS, 3); break; + + case Bytecodes::_lload_0: + case Bytecodes::_dload_0: ppload(vvCTS, 0); break; + case Bytecodes::_lload_1: + case Bytecodes::_dload_1: ppload(vvCTS, 1); break; + case Bytecodes::_lload_2: + case Bytecodes::_dload_2: ppload(vvCTS, 2); break; + case Bytecodes::_lload_3: + case Bytecodes::_dload_3: ppload(vvCTS, 3); break; + + case Bytecodes::_aload_0: ppload(rCTS, 0); break; + case Bytecodes::_aload_1: ppload(rCTS, 1); break; + case Bytecodes::_aload_2: ppload(rCTS, 2); break; + case Bytecodes::_aload_3: ppload(rCTS, 3); break; + + case Bytecodes::_iaload: + case Bytecodes::_faload: + case Bytecodes::_baload: + case Bytecodes::_caload: + case Bytecodes::_saload: pp(vrCTS, vCTS); break; + + case Bytecodes::_laload: pp(vrCTS, vvCTS); break; + case Bytecodes::_daload: pp(vrCTS, vvCTS); break; + + case Bytecodes::_aaload: pp_new_ref(vrCTS, itr->bci()); break; + + case Bytecodes::_istore: + case Bytecodes::_fstore: ppstore(vCTS, itr->get_index()); break; + + case Bytecodes::_lstore: + case Bytecodes::_dstore: ppstore(vvCTS, itr->get_index()); break; + + case Bytecodes::_astore: do_astore(itr->get_index()); break; + + case Bytecodes::_istore_0: + case Bytecodes::_fstore_0: ppstore(vCTS, 0); break; + case Bytecodes::_istore_1: + case Bytecodes::_fstore_1: ppstore(vCTS, 1); break; + case Bytecodes::_istore_2: + case Bytecodes::_fstore_2: ppstore(vCTS, 2); break; + case Bytecodes::_istore_3: + case Bytecodes::_fstore_3: ppstore(vCTS, 3); break; + + case Bytecodes::_lstore_0: + case Bytecodes::_dstore_0: ppstore(vvCTS, 0); break; + case Bytecodes::_lstore_1: + case Bytecodes::_dstore_1: ppstore(vvCTS, 1); break; + case Bytecodes::_lstore_2: + case Bytecodes::_dstore_2: ppstore(vvCTS, 2); break; + case Bytecodes::_lstore_3: + case Bytecodes::_dstore_3: ppstore(vvCTS, 3); break; + + case Bytecodes::_astore_0: do_astore(0); break; + case Bytecodes::_astore_1: do_astore(1); break; + case Bytecodes::_astore_2: do_astore(2); break; + case Bytecodes::_astore_3: do_astore(3); break; + + case Bytecodes::_iastore: + case Bytecodes::_fastore: + case Bytecodes::_bastore: + case Bytecodes::_castore: + case Bytecodes::_sastore: ppop(vvrCTS); break; + case Bytecodes::_lastore: + case Bytecodes::_dastore: ppop(vvvrCTS); break; + case Bytecodes::_aastore: ppop(rvrCTS); break; + + case Bytecodes::_pop: ppop_any(1); break; + case Bytecodes::_pop2: ppop_any(2); break; + + case Bytecodes::_dup: ppdupswap(1, "11"); break; + case Bytecodes::_dup_x1: ppdupswap(2, "121"); break; + case Bytecodes::_dup_x2: ppdupswap(3, "1321"); break; + case Bytecodes::_dup2: ppdupswap(2, "2121"); break; + case Bytecodes::_dup2_x1: ppdupswap(3, "21321"); break; + case Bytecodes::_dup2_x2: ppdupswap(4, "214321"); break; + case Bytecodes::_swap: ppdupswap(2, "12"); break; + + case Bytecodes::_iadd: + case Bytecodes::_fadd: + case Bytecodes::_isub: + case Bytecodes::_fsub: + case Bytecodes::_imul: + case Bytecodes::_fmul: + case Bytecodes::_idiv: + case Bytecodes::_fdiv: + case Bytecodes::_irem: + case Bytecodes::_frem: + case Bytecodes::_ishl: + case Bytecodes::_ishr: + case Bytecodes::_iushr: + case Bytecodes::_iand: + case Bytecodes::_ior: + case Bytecodes::_ixor: + case Bytecodes::_l2f: + case Bytecodes::_l2i: + case Bytecodes::_d2f: + case Bytecodes::_d2i: + case Bytecodes::_fcmpl: + case Bytecodes::_fcmpg: pp(vvCTS, vCTS); break; + + case Bytecodes::_ladd: + case Bytecodes::_dadd: + case Bytecodes::_lsub: + case Bytecodes::_dsub: + case Bytecodes::_lmul: + case Bytecodes::_dmul: + case Bytecodes::_ldiv: + case Bytecodes::_ddiv: + case Bytecodes::_lrem: + case Bytecodes::_drem: + case Bytecodes::_land: + case Bytecodes::_lor: + case Bytecodes::_lxor: pp(vvvvCTS, vvCTS); break; + + case Bytecodes::_ineg: + case Bytecodes::_fneg: + case Bytecodes::_i2f: + case Bytecodes::_f2i: + case Bytecodes::_i2c: + case Bytecodes::_i2s: + case Bytecodes::_i2b: pp(vCTS, vCTS); break; + + case Bytecodes::_lneg: + case Bytecodes::_dneg: + case Bytecodes::_l2d: + case Bytecodes::_d2l: pp(vvCTS, vvCTS); break; + + case Bytecodes::_lshl: + case Bytecodes::_lshr: + case Bytecodes::_lushr: pp(vvvCTS, vvCTS); break; + + case Bytecodes::_i2l: + case Bytecodes::_i2d: + case Bytecodes::_f2l: + case Bytecodes::_f2d: pp(vCTS, vvCTS); break; + + case Bytecodes::_lcmp: pp(vvvvCTS, vCTS); break; + case Bytecodes::_dcmpl: + case Bytecodes::_dcmpg: pp(vvvvCTS, vCTS); break; + + case Bytecodes::_ifeq: + case Bytecodes::_ifne: + case Bytecodes::_iflt: + case Bytecodes::_ifge: + case Bytecodes::_ifgt: + case Bytecodes::_ifle: + case Bytecodes::_tableswitch: ppop1(valCTS); + break; + case Bytecodes::_ireturn: + case Bytecodes::_freturn: do_return_monitor_check(); + ppop1(valCTS); + break; + case Bytecodes::_if_icmpeq: + case Bytecodes::_if_icmpne: + case Bytecodes::_if_icmplt: + case Bytecodes::_if_icmpge: + case Bytecodes::_if_icmpgt: + case Bytecodes::_if_icmple: ppop(vvCTS); + break; + + case Bytecodes::_lreturn: do_return_monitor_check(); + ppop(vvCTS); + break; + + case Bytecodes::_dreturn: do_return_monitor_check(); + ppop(vvCTS); + break; + + case Bytecodes::_if_acmpeq: + case Bytecodes::_if_acmpne: ppop(rrCTS); break; + + case Bytecodes::_jsr: do_jsr(itr->dest()); break; + case Bytecodes::_jsr_w: do_jsr(itr->dest_w()); break; + + case Bytecodes::_getstatic: do_field(true, true, + itr->get_index_big(), + itr->bci()); break; + case Bytecodes::_putstatic: do_field(false, true, itr->get_index_big(), itr->bci()); break; + case Bytecodes::_getfield: do_field(true, false, itr->get_index_big(), itr->bci()); break; + case Bytecodes::_putfield: do_field(false, false, itr->get_index_big(), itr->bci()); break; + + case Bytecodes::_invokevirtual: + case Bytecodes::_invokespecial: do_method(false, false, itr->get_index_big(), itr->bci()); break; + case Bytecodes::_invokestatic: do_method(true, false, itr->get_index_big(), itr->bci()); break; + case Bytecodes::_invokeinterface: do_method(false, true, itr->get_index_big(), itr->bci()); break; + case Bytecodes::_newarray: + case Bytecodes::_anewarray: pp_new_ref(vCTS, itr->bci()); break; + case Bytecodes::_checkcast: do_checkcast(); break; + case Bytecodes::_arraylength: + case Bytecodes::_instanceof: pp(rCTS, vCTS); break; + case Bytecodes::_monitorenter: do_monitorenter(itr->bci()); break; + case Bytecodes::_monitorexit: do_monitorexit(itr->bci()); break; + + case Bytecodes::_athrow: // handled by do_exception_edge() BUT ... + // vlh(apple): do_exception_edge() does not get + // called if method has no exception handlers + if ((!_has_exceptions) && (_monitor_top > 0)) { + _monitor_safe = false; + } + break; + + case Bytecodes::_areturn: do_return_monitor_check(); + ppop1(refCTS); + break; + case Bytecodes::_ifnull: + case Bytecodes::_ifnonnull: ppop1(refCTS); break; + case Bytecodes::_multianewarray: do_multianewarray(*(itr->bcp()+3), itr->bci()); break; + + case Bytecodes::_wide: fatal("Iterator should skip this bytecode"); break; + case Bytecodes::_ret: break; + + // Java opcodes + case Bytecodes::_lookupswitch: ppop1(valCTS); break; + + default: + tty->print("unexpected opcode: %d\n", itr->code()); + ShouldNotReachHere(); + break; + } +} + +void GenerateOopMap::check_type(CellTypeState expected, CellTypeState actual) { + if (!expected.equal_kind(actual)) { + verify_error("wrong type on stack (found: %c expected: %c)", actual.to_char(), expected.to_char()); + } +} + +void GenerateOopMap::ppstore(CellTypeState *in, int loc_no) { + while(!(*in).is_bottom()) { + CellTypeState expected =*in++; + CellTypeState actual = pop(); + check_type(expected, actual); + assert(loc_no >= 0, "sanity check"); + set_var(loc_no++, actual); + } +} + +void GenerateOopMap::ppload(CellTypeState *out, int loc_no) { + while(!(*out).is_bottom()) { + CellTypeState out1 = *out++; + CellTypeState vcts = get_var(loc_no); + assert(out1.can_be_reference() || out1.can_be_value(), + "can only load refs. and values."); + if (out1.is_reference()) { + assert(loc_no>=0, "sanity check"); + if (!vcts.is_reference()) { + // We were asked to push a reference, but the type of the + // variable can be something else + _conflict = true; + if (vcts.can_be_uninit()) { + // It is a ref-uninit conflict (at least). If there are other + // problems, we'll get them in the next round + add_to_ref_init_set(loc_no); + vcts = out1; + } else { + // It wasn't a ref-uninit conflict. So must be a + // ref-val or ref-pc conflict. Split the variable. + record_refval_conflict(loc_no); + vcts = out1; + } + push(out1); // recover... + } else { + push(vcts); // preserve reference. + } + // Otherwise it is a conflict, but one that verification would + // have caught if illegal. In particular, it can't be a topCTS + // resulting from mergeing two difference pcCTS's since the verifier + // would have rejected any use of such a merge. + } else { + push(out1); // handle val/init conflict + } + loc_no++; + } +} + +void GenerateOopMap::ppdupswap(int poplen, const char *out) { + CellTypeState actual[5]; + assert(poplen < 5, "this must be less than length of actual vector"); + + // pop all arguments + for(int i = 0; i < poplen; i++) actual[i] = pop(); + + // put them back + char push_ch = *out++; + while (push_ch != '\0') { + int idx = push_ch - '1'; + assert(idx >= 0 && idx < poplen, "wrong arguments"); + push(actual[idx]); + push_ch = *out++; + } +} + +void GenerateOopMap::ppop1(CellTypeState out) { + CellTypeState actual = pop(); + check_type(out, actual); +} + +void GenerateOopMap::ppop(CellTypeState *out) { + while (!(*out).is_bottom()) { + ppop1(*out++); + } +} + +void GenerateOopMap::ppush1(CellTypeState in) { + assert(in.is_reference() | in.is_value(), "sanity check"); + push(in); +} + +void GenerateOopMap::ppush(CellTypeState *in) { + while (!(*in).is_bottom()) { + ppush1(*in++); + } +} + +void GenerateOopMap::pp(CellTypeState *in, CellTypeState *out) { + ppop(in); + ppush(out); +} + +void GenerateOopMap::pp_new_ref(CellTypeState *in, int bci) { + ppop(in); + ppush1(CellTypeState::make_line_ref(bci)); +} + +void GenerateOopMap::ppop_any(int poplen) { + if (_stack_top >= poplen) { + _stack_top -= poplen; + } else { + verify_error("stack underflow"); + } +} + +// Replace all occurences of the state 'match' with the state 'replace' +// in our current state vector. +void GenerateOopMap::replace_all_CTS_matches(CellTypeState match, + CellTypeState replace) { + int i; + int len = _max_locals + _stack_top; + bool change = false; + + for (i = len - 1; i >= 0; i--) { + if (match.equal(_state[i])) { + _state[i] = replace; + } + } + + if (_monitor_top > 0) { + int base = _max_locals + _max_stack; + len = base + _monitor_top; + for (i = len - 1; i >= base; i--) { + if (match.equal(_state[i])) { + _state[i] = replace; + } + } + } +} + +void GenerateOopMap::do_checkcast() { + CellTypeState actual = pop(); + check_type(refCTS, actual); + push(actual); +} + +void GenerateOopMap::do_monitorenter(int bci) { + CellTypeState actual = pop(); + if (_monitor_top == bad_monitors) { + return; + } + + // Bail out when we get repeated locks on an identical monitor. This case + // isn't too hard to handle and can be made to work if supporting nested + // redundant synchronized statements becomes a priority. + // + // See also "Note" in do_monitorexit(), below. + if (actual.is_lock_reference()) { + _monitor_top = bad_monitors; + _monitor_safe = false; + + if (TraceMonitorMismatch) { + report_monitor_mismatch("nested redundant lock -- bailout..."); + } + return; + } + + CellTypeState lock = CellTypeState::make_lock_ref(bci); + check_type(refCTS, actual); + if (!actual.is_info_top()) { + replace_all_CTS_matches(actual, lock); + monitor_push(lock); + } +} + +void GenerateOopMap::do_monitorexit(int bci) { + CellTypeState actual = pop(); + if (_monitor_top == bad_monitors) { + return; + } + check_type(refCTS, actual); + CellTypeState expected = monitor_pop(); + if (!actual.is_lock_reference() || !expected.equal(actual)) { + // The monitor we are exiting is not verifiably the one + // on the top of our monitor stack. This causes a monitor + // mismatch. + _monitor_top = bad_monitors; + _monitor_safe = false; + + // We need to mark this basic block as changed so that + // this monitorexit will be visited again. We need to + // do this to ensure that we have accounted for the + // possibility that this bytecode will throw an + // exception. + BasicBlock* bb = get_basic_block_containing(bci); + bb->set_changed(true); + bb->_monitor_top = bad_monitors; + + if (TraceMonitorMismatch) { + report_monitor_mismatch("improper monitor pair"); + } + } else { + // This code is a fix for the case where we have repeated + // locking of the same object in straightline code. We clear + // out the lock when it is popped from the monitor stack + // and replace it with an unobtrusive reference value that can + // be locked again. + // + // Note: when generateOopMap is fixed to properly handle repeated, + // nested, redundant locks on the same object, then this + // fix will need to be removed at that time. + replace_all_CTS_matches(actual, CellTypeState::make_line_ref(bci)); + } +} + +void GenerateOopMap::do_return_monitor_check() { + if (_monitor_top > 0) { + // The monitor stack must be empty when we leave the method + // for the monitors to be properly matched. + _monitor_safe = false; + + // Since there are no successors to the *return bytecode, it + // isn't necessary to set _monitor_top to bad_monitors. + + if (TraceMonitorMismatch) { + report_monitor_mismatch("non-empty monitor stack at return"); + } + } +} + +void GenerateOopMap::do_jsr(int targ_bci) { + push(CellTypeState::make_addr(targ_bci)); +} + + + +void GenerateOopMap::do_ldc(int idx, int bci) { + constantPoolOop cp = method()->constants(); + constantTag tag = cp->tag_at(idx); + + CellTypeState cts = (tag.is_string() || tag.is_unresolved_string() || + tag.is_klass() || tag.is_unresolved_klass()) + ? CellTypeState::make_line_ref(bci) : valCTS; + ppush1(cts); +} + +void GenerateOopMap::do_multianewarray(int dims, int bci) { + assert(dims >= 1, "sanity check"); + for(int i = dims -1; i >=0; i--) { + ppop1(valCTS); + } + ppush1(CellTypeState::make_line_ref(bci)); +} + +void GenerateOopMap::do_astore(int idx) { + CellTypeState r_or_p = pop(); + if (!r_or_p.is_address() && !r_or_p.is_reference()) { + // We actually expected ref or pc, but we only report that we expected a ref. It does not + // really matter (at least for now) + verify_error("wrong type on stack (found: %c, expected: {pr})", r_or_p.to_char()); + return; + } + set_var(idx, r_or_p); +} + +// Copies bottom/zero terminated CTS string from "src" into "dst". +// Does NOT terminate with a bottom. Returns the number of cells copied. +int GenerateOopMap::copy_cts(CellTypeState *dst, CellTypeState *src) { + int idx = 0; + while (!src[idx].is_bottom()) { + dst[idx] = src[idx]; + idx++; + } + return idx; +} + +void GenerateOopMap::do_field(int is_get, int is_static, int idx, int bci) { + // Dig up signature for field in constant pool + constantPoolOop cp = method()->constants(); + int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx); + int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx); + symbolOop signature = cp->symbol_at(signatureIdx); + + // Parse signature (espcially simple for fields) + assert(signature->utf8_length() > 0, "field signatures cannot have zero length"); + // The signature is UFT8 encoded, but the first char is always ASCII for signatures. + char sigch = (char)*(signature->base()); + CellTypeState temp[4]; + CellTypeState *eff = sigchar_to_effect(sigch, bci, temp); + + CellTypeState in[4]; + CellTypeState *out; + int i = 0; + + if (is_get) { + out = eff; + } else { + out = epsilonCTS; + i = copy_cts(in, eff); + } + if (!is_static) in[i++] = CellTypeState::ref; + in[i] = CellTypeState::bottom; + assert(i<=3, "sanity check"); + pp(in, out); +} + +void GenerateOopMap::do_method(int is_static, int is_interface, int idx, int bci) { + // Dig up signature for field in constant pool + constantPoolOop cp = _method->constants(); + int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx); + int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx); + symbolOop signature = cp->symbol_at(signatureIdx); + + // Parse method signature + CellTypeState out[4]; + CellTypeState in[MAXARGSIZE+1]; // Includes result + ComputeCallStack cse(signature); + + // Compute return type + int res_length= cse.compute_for_returntype(out); + + // Temporary hack. + if (out[0].equal(CellTypeState::ref) && out[1].equal(CellTypeState::bottom)) { + out[0] = CellTypeState::make_line_ref(bci); + } + + assert(res_length<=4, "max value should be vv"); + + // Compute arguments + int arg_length = cse.compute_for_parameters(is_static != 0, in); + assert(arg_length<=MAXARGSIZE, "too many locals"); + + // Pop arguments + for (int i = arg_length - 1; i >= 0; i--) ppop1(in[i]);// Do args in reverse order. + + // Report results + if (_report_result_for_send == true) { + fill_stackmap_for_opcodes(_itr_send, vars(), stack(), _stack_top); + _report_result_for_send = false; + } + + // Push return address + ppush(out); +} + +// This is used to parse the signature for fields, since they are very simple... +CellTypeState *GenerateOopMap::sigchar_to_effect(char sigch, int bci, CellTypeState *out) { + // Object and array + if (sigch=='L' || sigch=='[') { + out[0] = CellTypeState::make_line_ref(bci); + out[1] = CellTypeState::bottom; + return out; + } + if (sigch == 'J' || sigch == 'D' ) return vvCTS; // Long and Double + if (sigch == 'V' ) return epsilonCTS; // Void + return vCTS; // Otherwise +} + +long GenerateOopMap::_total_byte_count = 0; +elapsedTimer GenerateOopMap::_total_oopmap_time; + +// This function assumes "bcs" is at a "ret" instruction and that the vars +// state is valid for that instruction. Furthermore, the ret instruction +// must be the last instruction in "bb" (we store information about the +// "ret" in "bb"). +void GenerateOopMap::ret_jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int varNo, int *data) { + CellTypeState ra = vars()[varNo]; + if (!ra.is_good_address()) { + verify_error("ret returns from two jsr subroutines?"); + return; + } + int target = ra.get_info(); + + RetTableEntry* rtEnt = _rt.find_jsrs_for_target(target); + int bci = bcs->bci(); + for (int i = 0; i < rtEnt->nof_jsrs(); i++) { + int target_bci = rtEnt->jsrs(i); + // Make sure a jrtRet does not set the changed bit for dead basicblock. + BasicBlock* jsr_bb = get_basic_block_containing(target_bci - 1); + debug_only(BasicBlock* target_bb = &jsr_bb[1];) + assert(target_bb == get_basic_block_at(target_bci), "wrong calc. of successor basicblock"); + bool alive = jsr_bb->is_alive(); + if (TraceNewOopMapGeneration) { + tty->print("pc = %d, ret -> %d alive: %s\n", bci, target_bci, alive ? "true" : "false"); + } + if (alive) jmpFct(this, target_bci, data); + } +} + +// +// Debug method +// +char* GenerateOopMap::state_vec_to_string(CellTypeState* vec, int len) { +#ifdef ASSERT + int checklen = MAX3(_max_locals, _max_stack, _max_monitors) + 1; + assert(len < checklen, "state_vec_buf overflow"); +#endif + for (int i = 0; i < len; i++) _state_vec_buf[i] = vec[i].to_char(); + _state_vec_buf[len] = 0; + return _state_vec_buf; +} + +void GenerateOopMap::print_time() { + tty->print_cr ("Accumulated oopmap times:"); + tty->print_cr ("---------------------------"); + tty->print_cr (" Total : %3.3f sec.", GenerateOopMap::_total_oopmap_time.seconds()); + tty->print_cr (" (%3.0f bytecodes per sec) ", + GenerateOopMap::_total_byte_count / GenerateOopMap::_total_oopmap_time.seconds()); +} + +// +// ============ Main Entry Point =========== +// +GenerateOopMap::GenerateOopMap(methodHandle method) { + // We have to initialize all variables here, that can be queried direcly + _method = method; + _max_locals=0; + _init_vars = NULL; + +#ifndef PRODUCT + // If we are doing a detailed trace, include the regular trace information. + if (TraceNewOopMapGenerationDetailed) { + TraceNewOopMapGeneration = true; + } +#endif +} + +void GenerateOopMap::compute_map(TRAPS) { +#ifndef PRODUCT + if (TimeOopMap2) { + method()->print_short_name(tty); + tty->print(" "); + } + if (TimeOopMap) { + _total_byte_count += method()->code_size(); + } +#endif + TraceTime t_single("oopmap time", TimeOopMap2); + TraceTime t_all(NULL, &_total_oopmap_time, TimeOopMap); + + // Initialize values + _got_error = false; + _conflict = false; + _max_locals = method()->max_locals(); + _max_stack = method()->max_stack(); + _has_exceptions = (method()->exception_table()->length() > 0); + _nof_refval_conflicts = 0; + _init_vars = new GrowableArray(5); // There are seldom more than 5 init_vars + _report_result = false; + _report_result_for_send = false; + _new_var_map = NULL; + _ret_adr_tos = new GrowableArray(5); // 5 seems like a good number; + _did_rewriting = false; + _did_relocation = false; + + if (TraceNewOopMapGeneration) { + tty->print("Method name: %s\n", method()->name()->as_C_string()); + if (Verbose) { + _method->print_codes(); + tty->print_cr("Exception table:"); + typeArrayOop excps = method()->exception_table(); + for(int i = 0; i < excps->length(); i += 4) { + tty->print_cr("[%d - %d] -> %d", excps->int_at(i + 0), excps->int_at(i + 1), excps->int_at(i + 2)); + } + } + } + + // if no code - do nothing + // compiler needs info + if (method()->code_size() == 0 || _max_locals + method()->max_stack() == 0) { + fill_stackmap_prolog(0); + fill_stackmap_epilog(); + return; + } + // Step 1: Compute all jump targets and their return value + if (!_got_error) + _rt.compute_ret_table(_method); + + // Step 2: Find all basic blocks and count GC points + if (!_got_error) + mark_bbheaders_and_count_gc_points(); + + // Step 3: Calculate stack maps + if (!_got_error) + do_interpretation(); + + // Step 4:Return results + if (!_got_error && report_results()) + report_result(); + + if (_got_error) { + THROW_HANDLE(_exception); + } +} + +// Error handling methods +// These methods create an exception for the current thread which is thrown +// at the bottom of the call stack, when it returns to compute_map(). The +// _got_error flag controls execution. NOT TODO: The VM exception propagation +// mechanism using TRAPS/CHECKs could be used here instead but it would need +// to be added as a parameter to every function and checked for every call. +// The tons of extra code it would generate didn't seem worth the change. +// +void GenerateOopMap::error_work(const char *format, va_list ap) { + _got_error = true; + char msg_buffer[512]; + vsnprintf(msg_buffer, sizeof(msg_buffer), format, ap); + // Append method name + char msg_buffer2[512]; + jio_snprintf(msg_buffer2, sizeof(msg_buffer2), "%s in method %s", msg_buffer, method()->name()->as_C_string()); + _exception = Exceptions::new_exception(Thread::current(), + vmSymbols::java_lang_LinkageError(), msg_buffer2); +} + +void GenerateOopMap::report_error(const char *format, ...) { + va_list ap; + va_start(ap, format); + error_work(format, ap); +} + +void GenerateOopMap::verify_error(const char *format, ...) { + // We do not distinguish between different types of errors for verification + // errors. Let the verifier give a better message. + const char *msg = "Illegal class file encountered. Try running with -Xverify:all"; + error_work(msg, NULL); +} + +// +// Report result opcodes +// +void GenerateOopMap::report_result() { + + if (TraceNewOopMapGeneration) tty->print_cr("Report result pass"); + + // We now want to report the result of the parse + _report_result = true; + + // Prolog code + fill_stackmap_prolog(_gc_points); + + // Mark everything changed, then do one interpretation pass. + for (int i = 0; i<_bb_count; i++) { + if (_basic_blocks[i].is_reachable()) { + _basic_blocks[i].set_changed(true); + interp_bb(&_basic_blocks[i]); + } + } + + // Note: Since we are skipping dead-code when we are reporting results, then + // the no. of encountered gc-points might be fewer than the previously number + // we have counted. (dead-code is a pain - it should be removed before we get here) + fill_stackmap_epilog(); + + // Report initvars + fill_init_vars(_init_vars); + + _report_result = false; +} + +void GenerateOopMap::result_for_basicblock(int bci) { + if (TraceNewOopMapGeneration) tty->print_cr("Report result pass for basicblock"); + + // We now want to report the result of the parse + _report_result = true; + + // Find basicblock and report results + BasicBlock* bb = get_basic_block_containing(bci); + assert(bb->is_reachable(), "getting result from unreachable basicblock"); + bb->set_changed(true); + interp_bb(bb); +} + +// +// Conflict handling code +// + +void GenerateOopMap::record_refval_conflict(int varNo) { + assert(varNo>=0 && varNo< _max_locals, "index out of range"); + + if (TraceOopMapRewrites) { + tty->print("### Conflict detected (local no: %d)\n", varNo); + } + + if (!_new_var_map) { + _new_var_map = NEW_RESOURCE_ARRAY(int, _max_locals); + for (int k = 0; k < _max_locals; k++) _new_var_map[k] = k; + } + + if ( _new_var_map[varNo] == varNo) { + // Check if max. number of locals has been reached + if (_max_locals + _nof_refval_conflicts >= MAX_LOCAL_VARS) { + report_error("Rewriting exceeded local variable limit"); + return; + } + _new_var_map[varNo] = _max_locals + _nof_refval_conflicts; + _nof_refval_conflicts++; + } +} + +void GenerateOopMap::rewrite_refval_conflicts() +{ + // We can get here two ways: Either a rewrite conflict was detected, or + // an uninitialize reference was detected. In the second case, we do not + // do any rewriting, we just want to recompute the reference set with the + // new information + + int nof_conflicts = 0; // Used for debugging only + + if ( _nof_refval_conflicts == 0 ) + return; + + // Check if rewrites are allowed in this parse. + if (!allow_rewrites() && !IgnoreRewrites) { + fatal("Rewriting method not allowed at this stage"); + } + + + // This following flag is to tempoary supress rewrites. The locals that might conflict will + // all be set to contain values. This is UNSAFE - however, until the rewriting has been completely + // tested it is nice to have. + if (IgnoreRewrites) { + if (Verbose) { + tty->print("rewrites suppressed for local no. "); + for (int l = 0; l < _max_locals; l++) { + if (_new_var_map[l] != l) { + tty->print("%d ", l); + vars()[l] = CellTypeState::value; + } + } + tty->cr(); + } + + // That was that... + _new_var_map = NULL; + _nof_refval_conflicts = 0; + _conflict = false; + + return; + } + + // Tracing flag + _did_rewriting = true; + + if (TraceOopMapRewrites) { + tty->print_cr("ref/value conflict for method %s - bytecodes are getting rewritten", method()->name()->as_C_string()); + method()->print(); + method()->print_codes(); + } + + assert(_new_var_map!=NULL, "nothing to rewrite"); + assert(_conflict==true, "We should not be here"); + + compute_ret_adr_at_TOS(); + if (!_got_error) { + for (int k = 0; k < _max_locals && !_got_error; k++) { + if (_new_var_map[k] != k) { + if (TraceOopMapRewrites) { + tty->print_cr("Rewriting: %d -> %d", k, _new_var_map[k]); + } + rewrite_refval_conflict(k, _new_var_map[k]); + if (_got_error) return; + nof_conflicts++; + } + } + } + + assert(nof_conflicts == _nof_refval_conflicts, "sanity check"); + + // Adjust the number of locals + method()->set_max_locals(_max_locals+_nof_refval_conflicts); + _max_locals += _nof_refval_conflicts; + + // That was that... + _new_var_map = NULL; + _nof_refval_conflicts = 0; +} + +void GenerateOopMap::rewrite_refval_conflict(int from, int to) { + bool startOver; + do { + // Make sure that the BytecodeStream is constructed in the loop, since + // during rewriting a new method oop is going to be used, and the next time + // around we want to use that. + BytecodeStream bcs(_method); + startOver = false; + + while( bcs.next() >=0 && !startOver && !_got_error) { + startOver = rewrite_refval_conflict_inst(&bcs, from, to); + } + } while (startOver && !_got_error); +} + +/* If the current instruction is one that uses local variable "from" + in a ref way, change it to use "to". There's a subtle reason why we + renumber the ref uses and not the non-ref uses: non-ref uses may be + 2 slots wide (double, long) which would necessitate keeping track of + whether we should add one or two variables to the method. If the change + affected the width of some instruction, returns "TRUE"; otherwise, returns "FALSE". + Another reason for moving ref's value is for solving (addr, ref) conflicts, which + both uses aload/astore methods. +*/ +bool GenerateOopMap::rewrite_refval_conflict_inst(BytecodeStream *itr, int from, int to) { + Bytecodes::Code bc = itr->code(); + int index; + int bci = itr->bci(); + + if (is_aload(itr, &index) && index == from) { + if (TraceOopMapRewrites) { + tty->print_cr("Rewriting aload at bci: %d", bci); + } + return rewrite_load_or_store(itr, Bytecodes::_aload, Bytecodes::_aload_0, to); + } + + if (is_astore(itr, &index) && index == from) { + if (!stack_top_holds_ret_addr(bci)) { + if (TraceOopMapRewrites) { + tty->print_cr("Rewriting astore at bci: %d", bci); + } + return rewrite_load_or_store(itr, Bytecodes::_astore, Bytecodes::_astore_0, to); + } else { + if (TraceOopMapRewrites) { + tty->print_cr("Supress rewriting of astore at bci: %d", bci); + } + } + } + + return false; +} + +// The argument to this method is: +// bc : Current bytecode +// bcN : either _aload or _astore +// bc0 : either _aload_0 or _astore_0 +bool GenerateOopMap::rewrite_load_or_store(BytecodeStream *bcs, Bytecodes::Code bcN, Bytecodes::Code bc0, unsigned int varNo) { + assert(bcN == Bytecodes::_astore || bcN == Bytecodes::_aload, "wrong argument (bcN)"); + assert(bc0 == Bytecodes::_astore_0 || bc0 == Bytecodes::_aload_0, "wrong argument (bc0)"); + int ilen = Bytecodes::length_at(bcs->bcp()); + int newIlen; + + if (ilen == 4) { + // Original instruction was wide; keep it wide for simplicity + newIlen = 4; + } else if (varNo < 4) + newIlen = 1; + else if (varNo >= 256) + newIlen = 4; + else + newIlen = 2; + + // If we need to relocate in order to patch the byte, we + // do the patching in a temp. buffer, that is passed to the reloc. + // The patching of the bytecode stream is then done by the Relocator. + // This is neccesary, since relocating the instruction at a certain bci, might + // also relocate that instruction, e.g., if a _goto before it gets widen to a _goto_w. + // Hence, we do not know which bci to patch after relocation. + + assert(newIlen <= 4, "sanity check"); + u_char inst_buffer[4]; // Max. instruction size is 4. + address bcp; + + if (newIlen != ilen) { + // Relocation needed do patching in temp. buffer + bcp = (address)inst_buffer; + } else { + bcp = _method->bcp_from(bcs->bci()); + } + + // Patch either directly in methodOop or in temp. buffer + if (newIlen == 1) { + assert(varNo < 4, "varNo too large"); + *bcp = bc0 + varNo; + } else if (newIlen == 2) { + assert(varNo < 256, "2-byte index needed!"); + *(bcp + 0) = bcN; + *(bcp + 1) = varNo; + } else { + assert(newIlen == 4, "Wrong instruction length"); + *(bcp + 0) = Bytecodes::_wide; + *(bcp + 1) = bcN; + Bytes::put_Java_u2(bcp+2, varNo); + } + + if (newIlen != ilen) { + expand_current_instr(bcs->bci(), ilen, newIlen, inst_buffer); + } + + + return (newIlen != ilen); +} + +class RelocCallback : public RelocatorListener { + private: + GenerateOopMap* _gom; + public: + RelocCallback(GenerateOopMap* gom) { _gom = gom; }; + + // Callback method + virtual void relocated(int bci, int delta, int new_code_length) { + _gom->update_basic_blocks (bci, delta, new_code_length); + _gom->update_ret_adr_at_TOS(bci, delta); + _gom->_rt.update_ret_table (bci, delta); + } +}; + +// Returns true if expanding was succesful. Otherwise, reports an error and +// returns false. +void GenerateOopMap::expand_current_instr(int bci, int ilen, int newIlen, u_char inst_buffer[]) { + Thread *THREAD = Thread::current(); // Could really have TRAPS argument. + RelocCallback rcb(this); + Relocator rc(_method, &rcb); + methodHandle m= rc.insert_space_at(bci, newIlen, inst_buffer, THREAD); + if (m.is_null() || HAS_PENDING_EXCEPTION) { + report_error("could not rewrite method - exception occurred or bytecode buffer overflow"); + return; + } + + // Relocator returns a new method oop. + _did_relocation = true; + _method = m; +} + + +bool GenerateOopMap::is_astore(BytecodeStream *itr, int *index) { + Bytecodes::Code bc = itr->code(); + switch(bc) { + case Bytecodes::_astore_0: + case Bytecodes::_astore_1: + case Bytecodes::_astore_2: + case Bytecodes::_astore_3: + *index = bc - Bytecodes::_astore_0; + return true; + case Bytecodes::_astore: + *index = itr->get_index(); + return true; + } + return false; +} + +bool GenerateOopMap::is_aload(BytecodeStream *itr, int *index) { + Bytecodes::Code bc = itr->code(); + switch(bc) { + case Bytecodes::_aload_0: + case Bytecodes::_aload_1: + case Bytecodes::_aload_2: + case Bytecodes::_aload_3: + *index = bc - Bytecodes::_aload_0; + return true; + + case Bytecodes::_aload: + *index = itr->get_index(); + return true; + } + return false; +} + + +// Return true iff the top of the operand stack holds a return address at +// the current instruction +bool GenerateOopMap::stack_top_holds_ret_addr(int bci) { + for(int i = 0; i < _ret_adr_tos->length(); i++) { + if (_ret_adr_tos->at(i) == bci) + return true; + } + + return false; +} + +void GenerateOopMap::compute_ret_adr_at_TOS() { + assert(_ret_adr_tos != NULL, "must be initialized"); + _ret_adr_tos->clear(); + + for (int i = 0; i < bb_count(); i++) { + BasicBlock* bb = &_basic_blocks[i]; + + // Make sure to only check basicblocks that are reachable + if (bb->is_reachable()) { + + // For each Basic block we check all instructions + BytecodeStream bcs(_method); + bcs.set_interval(bb->_bci, next_bb_start_pc(bb)); + + restore_state(bb); + + while (bcs.next()>=0 && !_got_error) { + // TDT: should this be is_good_address() ? + if (_stack_top > 0 && stack()[_stack_top-1].is_address()) { + _ret_adr_tos->append(bcs.bci()); + if (TraceNewOopMapGeneration) { + tty->print_cr("Ret_adr TOS at bci: %d", bcs.bci()); + } + } + interp1(&bcs); + } + } + } +} + +void GenerateOopMap::update_ret_adr_at_TOS(int bci, int delta) { + for(int i = 0; i < _ret_adr_tos->length(); i++) { + int v = _ret_adr_tos->at(i); + if (v > bci) _ret_adr_tos->at_put(i, v + delta); + } +} + +// =================================================================== + +#ifndef PRODUCT +int ResolveOopMapConflicts::_nof_invocations = 0; +int ResolveOopMapConflicts::_nof_rewrites = 0; +int ResolveOopMapConflicts::_nof_relocations = 0; +#endif + +methodHandle ResolveOopMapConflicts::do_potential_rewrite(TRAPS) { + compute_map(CHECK_(methodHandle())); + +#ifndef PRODUCT + // Tracking and statistics + if (PrintRewrites) { + _nof_invocations++; + if (did_rewriting()) { + _nof_rewrites++; + if (did_relocation()) _nof_relocations++; + tty->print("Method was rewritten %s: ", (did_relocation()) ? "and relocated" : ""); + method()->print_value(); tty->cr(); + tty->print_cr("Cand.: %d rewrts: %d (%d%%) reloc.: %d (%d%%)", + _nof_invocations, + _nof_rewrites, (_nof_rewrites * 100) / _nof_invocations, + _nof_relocations, (_nof_relocations * 100) / _nof_invocations); + } + } +#endif + return methodHandle(THREAD, method()); +}