/*
* Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "ci/ciMethod.hpp"
#include "ci/ciMethodBlocks.hpp"
#include "ci/ciStreams.hpp"
#include "compiler/methodLiveness.hpp"
#include "interpreter/bytecode.hpp"
#include "interpreter/bytecodes.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "runtime/timerTrace.hpp"
#include "utilities/bitMap.inline.hpp"
// The MethodLiveness class performs a simple liveness analysis on a method
// in order to decide which locals are live (that is, will be used again) at
// a particular bytecode index (bci).
//
// The algorithm goes:
//
// 1. Break the method into a set of basic blocks. For each basic block we
// also keep track of its set of predecessors through normal control flow
// and predecessors through exceptional control flow.
//
// 2. For each basic block, compute two sets, gen (the set of values used before
// they are defined) and kill (the set of values defined before they are used)
// in the basic block. A basic block "needs" the locals in its gen set to
// perform its computation. A basic block "provides" values for the locals in
// its kill set, allowing a need from a successor to be ignored.
//
// 3. Liveness information (the set of locals which are needed) is pushed backwards through
// the program, from blocks to their predecessors. We compute and store liveness
// information for the normal/exceptional exit paths for each basic block. When
// this process reaches a fixed point, we are done.
//
// 4. When we are asked about the liveness at a particular bci with a basic block, we
// compute gen/kill sets which represent execution from that bci to the exit of
// its blocks. We then compose this range gen/kill information with the normal
// and exceptional exit information for the block to produce liveness information
// at that bci.
//
// The algorithm is approximate in many respects. Notably:
//
// 1. We do not do the analysis necessary to match jsr's with the appropriate ret.
// Instead we make the conservative assumption that any ret can return to any
// jsr return site.
// 2. Instead of computing the effects of exceptions at every instruction, we
// summarize the effects of all exceptional continuations from the block as
// a single set (_exception_exit), losing some information but simplifying the
// analysis.
//--------------------------------------------------------------------------
// The BitCounter class is used for counting the number of bits set in
// some BitMap. It is only used when collecting liveness statistics.
#ifndef PRODUCT
class BitCounter: public BitMapClosure {
private:
int _count;
public:
BitCounter() : _count(0) {}
// Callback when bit in map is set
virtual bool do_bit(size_t offset) {
_count++;
return true;
}
int count() {
return _count;
}
};
//--------------------------------------------------------------------------
// Counts
long MethodLiveness::_total_bytes = 0;
int MethodLiveness::_total_methods = 0;
long MethodLiveness::_total_blocks = 0;
int MethodLiveness::_max_method_blocks = 0;
long MethodLiveness::_total_edges = 0;
int MethodLiveness::_max_block_edges = 0;
long MethodLiveness::_total_exc_edges = 0;
int MethodLiveness::_max_block_exc_edges = 0;
long MethodLiveness::_total_method_locals = 0;
int MethodLiveness::_max_method_locals = 0;
long MethodLiveness::_total_locals_queried = 0;
long MethodLiveness::_total_live_locals_queried = 0;
long MethodLiveness::_total_visits = 0;
#endif
// Timers
elapsedTimer MethodLiveness::_time_build_graph;
elapsedTimer MethodLiveness::_time_gen_kill;
elapsedTimer MethodLiveness::_time_flow;
elapsedTimer MethodLiveness::_time_query;
elapsedTimer MethodLiveness::_time_total;
MethodLiveness::MethodLiveness(Arena* arena, ciMethod* method)
#ifdef COMPILER1
: _bci_block_start(arena, method->code_size())
#endif
{
_arena = arena;
_method = method;
_bit_map_size_bits = method->max_locals();
}
void MethodLiveness::compute_liveness() {
#ifndef PRODUCT
if (TraceLivenessGen) {
tty->print_cr("################################################################");
tty->print("# Computing liveness information for ");
method()->print_short_name();
}
if (TimeLivenessAnalysis) _time_total.start();
#endif
{
TraceTime buildGraph(NULL, &_time_build_graph, TimeLivenessAnalysis);
init_basic_blocks();
}
{
TraceTime genKill(NULL, &_time_gen_kill, TimeLivenessAnalysis);
init_gen_kill();
}
{
TraceTime flow(NULL, &_time_flow, TimeLivenessAnalysis);
propagate_liveness();
}
#ifndef PRODUCT
if (TimeLivenessAnalysis) _time_total.stop();
if (TimeLivenessAnalysis) {
// Collect statistics
_total_bytes += method()->code_size();
_total_methods++;
int num_blocks = _block_count;
_total_blocks += num_blocks;
_max_method_blocks = MAX2(num_blocks,_max_method_blocks);
for (int i=0; i<num_blocks; i++) {
BasicBlock *block = _block_list[i];
int numEdges = block->_normal_predecessors->length();
int numExcEdges = block->_exception_predecessors->length();
_total_edges += numEdges;
_total_exc_edges += numExcEdges;
_max_block_edges = MAX2(numEdges,_max_block_edges);
_max_block_exc_edges = MAX2(numExcEdges,_max_block_exc_edges);
}
int numLocals = _bit_map_size_bits;
_total_method_locals += numLocals;
_max_method_locals = MAX2(numLocals,_max_method_locals);
}
#endif
}
void MethodLiveness::init_basic_blocks() {
bool bailout = false;
int method_len = method()->code_size();
ciMethodBlocks *mblocks = method()->get_method_blocks();
// Create an array to store the bci->BasicBlock mapping.
_block_map = new (arena()) GrowableArray<BasicBlock*>(arena(), method_len, method_len, NULL);
_block_count = mblocks->num_blocks();
_block_list = (BasicBlock **) arena()->Amalloc(sizeof(BasicBlock *) * _block_count);
// Used for patching up jsr/ret control flow.
GrowableArray<BasicBlock*>* jsr_exit_list = new GrowableArray<BasicBlock*>(5);
GrowableArray<BasicBlock*>* ret_list = new GrowableArray<BasicBlock*>(5);
// generate our block list from ciMethodBlocks
for (int blk = 0; blk < _block_count; blk++) {
ciBlock *cib = mblocks->block(blk);
int start_bci = cib->start_bci();
_block_list[blk] = new (arena()) BasicBlock(this, start_bci, cib->limit_bci());
_block_map->at_put(start_bci, _block_list[blk]);
#ifdef COMPILER1
// mark all bcis where a new basic block starts
_bci_block_start.set_bit(start_bci);
#endif // COMPILER1
}
// fill in the predecessors of blocks
ciBytecodeStream bytes(method());
for (int blk = 0; blk < _block_count; blk++) {
BasicBlock *current_block = _block_list[blk];
int bci = mblocks->block(blk)->control_bci();
if (bci == ciBlock::fall_through_bci) {
int limit = current_block->limit_bci();
if (limit < method_len) {
BasicBlock *next = _block_map->at(limit);
assert( next != NULL, "must be a block immediately following this one.");
next->add_normal_predecessor(current_block);
}
continue;
}
bytes.reset_to_bci(bci);
Bytecodes::Code code = bytes.next();
BasicBlock *dest;
// Now we need to interpret the instruction's effect
// on control flow.
assert (current_block != NULL, "we must have a current block");
switch (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:
// Two way branch. Set predecessors at each destination.
dest = _block_map->at(bytes.next_bci());
assert(dest != NULL, "must be a block immediately following this one.");
dest->add_normal_predecessor(current_block);
dest = _block_map->at(bytes.get_dest());
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
break;
case Bytecodes::_goto:
dest = _block_map->at(bytes.get_dest());
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
break;
case Bytecodes::_goto_w:
dest = _block_map->at(bytes.get_far_dest());
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
break;
case Bytecodes::_tableswitch:
{
Bytecode_tableswitch tableswitch(&bytes);
int len = tableswitch.length();
dest = _block_map->at(bci + tableswitch.default_offset());
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
while (--len >= 0) {
dest = _block_map->at(bci + tableswitch.dest_offset_at(len));
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
}
break;
}
case Bytecodes::_lookupswitch:
{
Bytecode_lookupswitch lookupswitch(&bytes);
int npairs = lookupswitch.number_of_pairs();
dest = _block_map->at(bci + lookupswitch.default_offset());
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
while(--npairs >= 0) {
LookupswitchPair pair = lookupswitch.pair_at(npairs);
dest = _block_map->at( bci + pair.offset());
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
}
break;
}
case Bytecodes::_jsr:
{
assert(bytes.is_wide()==false, "sanity check");
dest = _block_map->at(bytes.get_dest());
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
BasicBlock *jsrExit = _block_map->at(current_block->limit_bci());
assert(jsrExit != NULL, "jsr return bci must start a block.");
jsr_exit_list->append(jsrExit);
break;
}
case Bytecodes::_jsr_w:
{
dest = _block_map->at(bytes.get_far_dest());
assert(dest != NULL, "branch desination must start a block.");
dest->add_normal_predecessor(current_block);
BasicBlock *jsrExit = _block_map->at(current_block->limit_bci());
assert(jsrExit != NULL, "jsr return bci must start a block.");
jsr_exit_list->append(jsrExit);
break;
}
case Bytecodes::_wide:
assert(false, "wide opcodes should not be seen here");
break;
case Bytecodes::_athrow:
case Bytecodes::_ireturn:
case Bytecodes::_lreturn:
case Bytecodes::_freturn:
case Bytecodes::_dreturn:
case Bytecodes::_areturn:
case Bytecodes::_return:
// These opcodes are not the normal predecessors of any other opcodes.
break;
case Bytecodes::_ret:
// We will patch up jsr/rets in a subsequent pass.
ret_list->append(current_block);
break;
case Bytecodes::_breakpoint:
// Bail out of there are breakpoints in here.
bailout = true;
break;
default:
// Do nothing.
break;
}
}
// Patch up the jsr/ret's. We conservatively assume that any ret
// can return to any jsr site.
int ret_list_len = ret_list->length();
int jsr_exit_list_len = jsr_exit_list->length();
if (ret_list_len > 0 && jsr_exit_list_len > 0) {
for (int i = jsr_exit_list_len - 1; i >= 0; i--) {
BasicBlock *jsrExit = jsr_exit_list->at(i);
for (int i = ret_list_len - 1; i >= 0; i--) {
jsrExit->add_normal_predecessor(ret_list->at(i));
}
}
}
// Compute exception edges.
for (int b=_block_count-1; b >= 0; b--) {
BasicBlock *block = _block_list[b];
int block_start = block->start_bci();
int block_limit = block->limit_bci();
ciExceptionHandlerStream handlers(method());
for (; !handlers.is_done(); handlers.next()) {
ciExceptionHandler* handler = handlers.handler();
int start = handler->start();
int limit = handler->limit();
int handler_bci = handler->handler_bci();
int intersect_start = MAX2(block_start, start);
int intersect_limit = MIN2(block_limit, limit);
if (intersect_start < intersect_limit) {
// The catch range has a nonempty intersection with this
// basic block. That means this basic block can be an
// exceptional predecessor.
_block_map->at(handler_bci)->add_exception_predecessor(block);
if (handler->is_catch_all()) {
// This is a catch-all block.
if (intersect_start == block_start && intersect_limit == block_limit) {
// The basic block is entirely contained in this catch-all block.
// Skip the rest of the exception handlers -- they can never be
// reached in execution.
break;
}
}
}
}
}
}
void MethodLiveness::init_gen_kill() {
for (int i=_block_count-1; i >= 0; i--) {
_block_list[i]->compute_gen_kill(method());
}
}
void MethodLiveness::propagate_liveness() {
int num_blocks = _block_count;
BasicBlock *block;
// We start our work list off with all blocks in it.
// Alternately, we could start off the work list with the list of all
// blocks which could exit the method directly, along with one block
// from any infinite loop. If this matters, it can be changed. It
// may not be clear from looking at the code, but the order of the
// workList will be the opposite of the creation order of the basic
// blocks, which should be decent for quick convergence (with the
// possible exception of exception handlers, which are all created
// early).
_work_list = NULL;
for (int i = 0; i < num_blocks; i++) {
block = _block_list[i];
block->set_next(_work_list);
block->set_on_work_list(true);
_work_list = block;
}
while ((block = work_list_get()) != NULL) {
block->propagate(this);
NOT_PRODUCT(_total_visits++;)
}
}
void MethodLiveness::work_list_add(BasicBlock *block) {
if (!block->on_work_list()) {
block->set_next(_work_list);
block->set_on_work_list(true);
_work_list = block;
}
}
MethodLiveness::BasicBlock *MethodLiveness::work_list_get() {
BasicBlock *block = _work_list;
if (block != NULL) {
block->set_on_work_list(false);
_work_list = block->next();
}
return block;
}
MethodLivenessResult MethodLiveness::get_liveness_at(int entry_bci) {
int bci = entry_bci;
bool is_entry = false;
if (entry_bci == InvocationEntryBci) {
is_entry = true;
bci = 0;
}
MethodLivenessResult answer;
if (_block_count > 0) {
if (TimeLivenessAnalysis) _time_total.start();
if (TimeLivenessAnalysis) _time_query.start();
assert( 0 <= bci && bci < method()->code_size(), "bci out of range" );
BasicBlock *block = _block_map->at(bci);
// We may not be at the block start, so search backwards to find the block
// containing bci.
int t = bci;
while (block == NULL && t > 0) {
block = _block_map->at(--t);
}
guarantee(block != NULL, "invalid bytecode index; must be instruction index");
assert(bci >= block->start_bci() && bci < block->limit_bci(), "block must contain bci.");
answer = block->get_liveness_at(method(), bci);
if (is_entry && method()->is_synchronized() && !method()->is_static()) {
// Synchronized methods use the receiver once on entry.
answer.at_put(0, true);
}
#ifndef PRODUCT
if (TraceLivenessQuery) {
tty->print("Liveness query of ");
method()->print_short_name();
tty->print(" @ %d : result is ", bci);
answer.print_on(tty);
}
if (TimeLivenessAnalysis) _time_query.stop();
if (TimeLivenessAnalysis) _time_total.stop();
#endif
}
#ifndef PRODUCT
if (TimeLivenessAnalysis) {
// Collect statistics.
_total_locals_queried += _bit_map_size_bits;
BitCounter counter;
answer.iterate(&counter);
_total_live_locals_queried += counter.count();
}
#endif
return answer;
}
#ifndef PRODUCT
void MethodLiveness::print_times() {
tty->print_cr ("Accumulated liveness analysis times/statistics:");
tty->print_cr ("-----------------------------------------------");
tty->print_cr (" Total : %3.3f sec.", _time_total.seconds());
tty->print_cr (" Build graph : %3.3f sec. (%2.2f%%)", _time_build_graph.seconds(),
_time_build_graph.seconds() * 100 / _time_total.seconds());
tty->print_cr (" Gen / Kill : %3.3f sec. (%2.2f%%)", _time_gen_kill.seconds(),
_time_gen_kill.seconds() * 100 / _time_total.seconds());
tty->print_cr (" Dataflow : %3.3f sec. (%2.2f%%)", _time_flow.seconds(),
_time_flow.seconds() * 100 / _time_total.seconds());
tty->print_cr (" Query : %3.3f sec. (%2.2f%%)", _time_query.seconds(),
_time_query.seconds() * 100 / _time_total.seconds());
tty->print_cr (" #bytes : %8ld (%3.0f bytes per sec)",
_total_bytes,
_total_bytes / _time_total.seconds());
tty->print_cr (" #methods : %8d (%3.0f methods per sec)",
_total_methods,
_total_methods / _time_total.seconds());
tty->print_cr (" avg locals : %3.3f max locals : %3d",
(float)_total_method_locals / _total_methods,
_max_method_locals);
tty->print_cr (" avg blocks : %3.3f max blocks : %3d",
(float)_total_blocks / _total_methods,
_max_method_blocks);
tty->print_cr (" avg bytes : %3.3f",
(float)_total_bytes / _total_methods);
tty->print_cr (" #blocks : %8ld",
_total_blocks);
tty->print_cr (" avg normal predecessors : %3.3f max normal predecessors : %3d",
(float)_total_edges / _total_blocks,
_max_block_edges);
tty->print_cr (" avg exception predecessors : %3.3f max exception predecessors : %3d",
(float)_total_exc_edges / _total_blocks,
_max_block_exc_edges);
tty->print_cr (" avg visits : %3.3f",
(float)_total_visits / _total_blocks);
tty->print_cr (" #locals queried : %8ld #live : %8ld %%live : %2.2f%%",
_total_locals_queried,
_total_live_locals_queried,
100.0 * _total_live_locals_queried / _total_locals_queried);
}
#endif
MethodLiveness::BasicBlock::BasicBlock(MethodLiveness *analyzer, int start, int limit) :
_gen(analyzer->arena(), analyzer->bit_map_size_bits()),
_kill(analyzer->arena(), analyzer->bit_map_size_bits()),
_entry(analyzer->arena(), analyzer->bit_map_size_bits()),
_normal_exit(analyzer->arena(), analyzer->bit_map_size_bits()),
_exception_exit(analyzer->arena(), analyzer->bit_map_size_bits()),
_last_bci(-1) {
_analyzer = analyzer;
_start_bci = start;
_limit_bci = limit;
_normal_predecessors =
new (analyzer->arena()) GrowableArray<MethodLiveness::BasicBlock*>(analyzer->arena(), 5, 0, NULL);
_exception_predecessors =
new (analyzer->arena()) GrowableArray<MethodLiveness::BasicBlock*>(analyzer->arena(), 5, 0, NULL);
}
MethodLiveness::BasicBlock *MethodLiveness::BasicBlock::split(int split_bci) {
int start = _start_bci;
int limit = _limit_bci;
if (TraceLivenessGen) {
tty->print_cr(" ** Splitting block (%d,%d) at %d", start, limit, split_bci);
}
GrowableArray<BasicBlock*>* save_predecessors = _normal_predecessors;
assert (start < split_bci && split_bci < limit, "improper split");
// Make a new block to cover the first half of the range.
BasicBlock *first_half = new (_analyzer->arena()) BasicBlock(_analyzer, start, split_bci);
// Assign correct values to the second half (this)
_normal_predecessors = first_half->_normal_predecessors;
_start_bci = split_bci;
add_normal_predecessor(first_half);
// Assign correct predecessors to the new first half
first_half->_normal_predecessors = save_predecessors;
return first_half;
}
void MethodLiveness::BasicBlock::compute_gen_kill(ciMethod* method) {
ciBytecodeStream bytes(method);
bytes.reset_to_bci(start_bci());
bytes.set_max_bci(limit_bci());
compute_gen_kill_range(&bytes);
}
void MethodLiveness::BasicBlock::compute_gen_kill_range(ciBytecodeStream *bytes) {
_gen.clear();
_kill.clear();
while (bytes->next() != ciBytecodeStream::EOBC()) {
compute_gen_kill_single(bytes);
}
}
void MethodLiveness::BasicBlock::compute_gen_kill_single(ciBytecodeStream *instruction) {
int localNum;
// We prohibit _gen and _kill from having locals in common. If we
// know that one is definitely going to be applied before the other,
// we could save some computation time by relaxing this prohibition.
switch (instruction->cur_bc()) {
case Bytecodes::_nop:
case Bytecodes::_goto:
case Bytecodes::_goto_w:
case Bytecodes::_aconst_null:
case Bytecodes::_new:
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:
case Bytecodes::_lconst_0:
case Bytecodes::_lconst_1:
case Bytecodes::_dconst_0:
case Bytecodes::_dconst_1:
case Bytecodes::_ldc2_w:
case Bytecodes::_ldc:
case Bytecodes::_ldc_w:
case Bytecodes::_iaload:
case Bytecodes::_faload:
case Bytecodes::_baload:
case Bytecodes::_caload:
case Bytecodes::_saload:
case Bytecodes::_laload:
case Bytecodes::_daload:
case Bytecodes::_aaload:
case Bytecodes::_iastore:
case Bytecodes::_fastore:
case Bytecodes::_bastore:
case Bytecodes::_castore:
case Bytecodes::_sastore:
case Bytecodes::_lastore:
case Bytecodes::_dastore:
case Bytecodes::_aastore:
case Bytecodes::_pop:
case Bytecodes::_pop2:
case Bytecodes::_dup:
case Bytecodes::_dup_x1:
case Bytecodes::_dup_x2:
case Bytecodes::_dup2:
case Bytecodes::_dup2_x1:
case Bytecodes::_dup2_x2:
case Bytecodes::_swap:
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:
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:
case Bytecodes::_ineg:
case Bytecodes::_fneg:
case Bytecodes::_i2f:
case Bytecodes::_f2i:
case Bytecodes::_i2c:
case Bytecodes::_i2s:
case Bytecodes::_i2b:
case Bytecodes::_lneg:
case Bytecodes::_dneg:
case Bytecodes::_l2d:
case Bytecodes::_d2l:
case Bytecodes::_lshl:
case Bytecodes::_lshr:
case Bytecodes::_lushr:
case Bytecodes::_i2l:
case Bytecodes::_i2d:
case Bytecodes::_f2l:
case Bytecodes::_f2d:
case Bytecodes::_lcmp:
case Bytecodes::_dcmpl:
case Bytecodes::_dcmpg:
case Bytecodes::_ifeq:
case Bytecodes::_ifne:
case Bytecodes::_iflt:
case Bytecodes::_ifge:
case Bytecodes::_ifgt:
case Bytecodes::_ifle:
case Bytecodes::_tableswitch:
case Bytecodes::_ireturn:
case Bytecodes::_freturn:
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::_lreturn:
case Bytecodes::_dreturn:
case Bytecodes::_if_acmpeq:
case Bytecodes::_if_acmpne:
case Bytecodes::_jsr:
case Bytecodes::_jsr_w:
case Bytecodes::_getstatic:
case Bytecodes::_putstatic:
case Bytecodes::_getfield:
case Bytecodes::_putfield:
case Bytecodes::_invokevirtual:
case Bytecodes::_invokespecial:
case Bytecodes::_invokestatic:
case Bytecodes::_invokeinterface:
case Bytecodes::_invokedynamic:
case Bytecodes::_newarray:
case Bytecodes::_anewarray:
case Bytecodes::_checkcast:
case Bytecodes::_arraylength:
case Bytecodes::_instanceof:
case Bytecodes::_athrow:
case Bytecodes::_areturn:
case Bytecodes::_monitorenter:
case Bytecodes::_monitorexit:
case Bytecodes::_ifnull:
case Bytecodes::_ifnonnull:
case Bytecodes::_multianewarray:
case Bytecodes::_lookupswitch:
// These bytecodes have no effect on the method's locals.
break;
case Bytecodes::_return:
if (instruction->method()->intrinsic_id() == vmIntrinsics::_Object_init) {
// return from Object.init implicitly registers a finalizer
// for the receiver if needed, so keep it alive.
load_one(0);
}
break;
case Bytecodes::_lload:
case Bytecodes::_dload:
load_two(instruction->get_index());
break;
case Bytecodes::_lload_0:
case Bytecodes::_dload_0:
load_two(0);
break;
case Bytecodes::_lload_1:
case Bytecodes::_dload_1:
load_two(1);
break;
case Bytecodes::_lload_2:
case Bytecodes::_dload_2:
load_two(2);
break;
case Bytecodes::_lload_3:
case Bytecodes::_dload_3:
load_two(3);
break;
case Bytecodes::_iload:
case Bytecodes::_iinc:
case Bytecodes::_fload:
case Bytecodes::_aload:
case Bytecodes::_ret:
load_one(instruction->get_index());
break;
case Bytecodes::_iload_0:
case Bytecodes::_fload_0:
case Bytecodes::_aload_0:
load_one(0);
break;
case Bytecodes::_iload_1:
case Bytecodes::_fload_1:
case Bytecodes::_aload_1:
load_one(1);
break;
case Bytecodes::_iload_2:
case Bytecodes::_fload_2:
case Bytecodes::_aload_2:
load_one(2);
break;
case Bytecodes::_iload_3:
case Bytecodes::_fload_3:
case Bytecodes::_aload_3:
load_one(3);
break;
case Bytecodes::_lstore:
case Bytecodes::_dstore:
store_two(localNum = instruction->get_index());
break;
case Bytecodes::_lstore_0:
case Bytecodes::_dstore_0:
store_two(0);
break;
case Bytecodes::_lstore_1:
case Bytecodes::_dstore_1:
store_two(1);
break;
case Bytecodes::_lstore_2:
case Bytecodes::_dstore_2:
store_two(2);
break;
case Bytecodes::_lstore_3:
case Bytecodes::_dstore_3:
store_two(3);
break;
case Bytecodes::_istore:
case Bytecodes::_fstore:
case Bytecodes::_astore:
store_one(instruction->get_index());
break;
case Bytecodes::_istore_0:
case Bytecodes::_fstore_0:
case Bytecodes::_astore_0:
store_one(0);
break;
case Bytecodes::_istore_1:
case Bytecodes::_fstore_1:
case Bytecodes::_astore_1:
store_one(1);
break;
case Bytecodes::_istore_2:
case Bytecodes::_fstore_2:
case Bytecodes::_astore_2:
store_one(2);
break;
case Bytecodes::_istore_3:
case Bytecodes::_fstore_3:
case Bytecodes::_astore_3:
store_one(3);
break;
case Bytecodes::_wide:
fatal("Iterator should skip this bytecode");
break;
default:
tty->print("unexpected opcode: %d\n", instruction->cur_bc());
ShouldNotReachHere();
break;
}
}
void MethodLiveness::BasicBlock::load_two(int local) {
load_one(local);
load_one(local+1);
}
void MethodLiveness::BasicBlock::load_one(int local) {
if (!_kill.at(local)) {
_gen.at_put(local, true);
}
}
void MethodLiveness::BasicBlock::store_two(int local) {
store_one(local);
store_one(local+1);
}
void MethodLiveness::BasicBlock::store_one(int local) {
if (!_gen.at(local)) {
_kill.at_put(local, true);
}
}
void MethodLiveness::BasicBlock::propagate(MethodLiveness *ml) {
// These set operations could be combined for efficiency if the
// performance of this analysis becomes an issue.
_entry.set_union(_normal_exit);
_entry.set_difference(_kill);
_entry.set_union(_gen);
// Note that we merge information from our exceptional successors
// just once, rather than at individual bytecodes.
_entry.set_union(_exception_exit);
if (TraceLivenessGen) {
tty->print_cr(" ** Visiting block at %d **", start_bci());
print_on(tty);
}
int i;
for (i=_normal_predecessors->length()-1; i>=0; i--) {
BasicBlock *block = _normal_predecessors->at(i);
if (block->merge_normal(_entry)) {
ml->work_list_add(block);
}
}
for (i=_exception_predecessors->length()-1; i>=0; i--) {
BasicBlock *block = _exception_predecessors->at(i);
if (block->merge_exception(_entry)) {
ml->work_list_add(block);
}
}
}
bool MethodLiveness::BasicBlock::merge_normal(const BitMap& other) {
return _normal_exit.set_union_with_result(other);
}
bool MethodLiveness::BasicBlock::merge_exception(const BitMap& other) {
return _exception_exit.set_union_with_result(other);
}
MethodLivenessResult MethodLiveness::BasicBlock::get_liveness_at(ciMethod* method, int bci) {
MethodLivenessResult answer(_analyzer->bit_map_size_bits());
answer.set_is_valid();
#ifndef ASSERT
if (bci == start_bci()) {
answer.set_from(_entry);
return answer;
}
#endif
#ifdef ASSERT
ResourceMark rm;
ResourceBitMap g(_gen.size()); g.set_from(_gen);
ResourceBitMap k(_kill.size()); k.set_from(_kill);
#endif
if (_last_bci != bci || trueInDebug) {
ciBytecodeStream bytes(method);
bytes.reset_to_bci(bci);
bytes.set_max_bci(limit_bci());
compute_gen_kill_range(&bytes);
assert(_last_bci != bci ||
(g.is_same(_gen) && k.is_same(_kill)), "cached computation is incorrect");
_last_bci = bci;
}
answer.set_union(_normal_exit);
answer.set_difference(_kill);
answer.set_union(_gen);
answer.set_union(_exception_exit);
#ifdef ASSERT
if (bci == start_bci()) {
assert(answer.is_same(_entry), "optimized answer must be accurate");
}
#endif
return answer;
}
#ifndef PRODUCT
void MethodLiveness::BasicBlock::print_on(outputStream *os) const {
os->print_cr("===================================================================");
os->print_cr(" Block start: %4d, limit: %4d", _start_bci, _limit_bci);
os->print (" Normal predecessors (%2d) @", _normal_predecessors->length());
int i;
for (i=0; i < _normal_predecessors->length(); i++) {
os->print(" %4d", _normal_predecessors->at(i)->start_bci());
}
os->cr();
os->print (" Exceptional predecessors (%2d) @", _exception_predecessors->length());
for (i=0; i < _exception_predecessors->length(); i++) {
os->print(" %4d", _exception_predecessors->at(i)->start_bci());
}
os->cr();
os->print (" Normal Exit : ");
_normal_exit.print_on(os);
os->print (" Gen : ");
_gen.print_on(os);
os->print (" Kill : ");
_kill.print_on(os);
os->print (" Exception Exit: ");
_exception_exit.print_on(os);
os->print (" Entry : ");
_entry.print_on(os);
}
#endif // PRODUCT