JDK14/Java14源码在线阅读
/*
* Copyright (c) 2005, 2019, 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/bcEscapeAnalyzer.hpp"
#include "ci/ciConstant.hpp"
#include "ci/ciField.hpp"
#include "ci/ciMethodBlocks.hpp"
#include "ci/ciStreams.hpp"
#include "interpreter/bytecode.hpp"
#include "oops/oop.inline.hpp"
#include "utilities/align.hpp"
#include "utilities/bitMap.inline.hpp"
#include "utilities/copy.hpp"
#ifndef PRODUCT
#define TRACE_BCEA(level, code) \
if (EstimateArgEscape && BCEATraceLevel >= level) { \
code; \
}
#else
#define TRACE_BCEA(level, code)
#endif
// Maintain a map of which arguments a local variable or
// stack slot may contain. In addition to tracking
// arguments, it tracks two special values, "allocated"
// which represents any object allocated in the current
// method, and "unknown" which is any other object.
// Up to 30 arguments are handled, with the last one
// representing summary information for any extra arguments
class BCEscapeAnalyzer::ArgumentMap {
uint _bits;
enum {MAXBIT = 29,
ALLOCATED = 1,
UNKNOWN = 2};
uint int_to_bit(uint e) const {
if (e > MAXBIT)
e = MAXBIT;
return (1 << (e + 2));
}
public:
ArgumentMap() { _bits = 0;}
void set_bits(uint bits) { _bits = bits;}
uint get_bits() const { return _bits;}
void clear() { _bits = 0;}
void set_all() { _bits = ~0u; }
bool is_empty() const { return _bits == 0; }
bool contains(uint var) const { return (_bits & int_to_bit(var)) != 0; }
bool is_singleton(uint var) const { return (_bits == int_to_bit(var)); }
bool contains_unknown() const { return (_bits & UNKNOWN) != 0; }
bool contains_allocated() const { return (_bits & ALLOCATED) != 0; }
bool contains_vars() const { return (_bits & (((1 << MAXBIT) -1) << 2)) != 0; }
void set(uint var) { _bits = int_to_bit(var); }
void add(uint var) { _bits |= int_to_bit(var); }
void add_unknown() { _bits = UNKNOWN; }
void add_allocated() { _bits = ALLOCATED; }
void set_union(const ArgumentMap &am) { _bits |= am._bits; }
void set_difference(const ArgumentMap &am) { _bits &= ~am._bits; }
void operator=(const ArgumentMap &am) { _bits = am._bits; }
bool operator==(const ArgumentMap &am) { return _bits == am._bits; }
bool operator!=(const ArgumentMap &am) { return _bits != am._bits; }
};
class BCEscapeAnalyzer::StateInfo {
public:
ArgumentMap *_vars;
ArgumentMap *_stack;
int _stack_height;
int _max_stack;
bool _initialized;
ArgumentMap empty_map;
StateInfo() {
empty_map.clear();
}
ArgumentMap raw_pop() { guarantee(_stack_height > 0, "stack underflow"); return _stack[--_stack_height]; }
ArgumentMap apop() { return raw_pop(); }
void spop() { raw_pop(); }
void lpop() { spop(); spop(); }
void raw_push(ArgumentMap i) { guarantee(_stack_height < _max_stack, "stack overflow"); _stack[_stack_height++] = i; }
void apush(ArgumentMap i) { raw_push(i); }
void spush() { raw_push(empty_map); }
void lpush() { spush(); spush(); }
};
void BCEscapeAnalyzer::set_returned(ArgumentMap vars) {
for (int i = 0; i < _arg_size; i++) {
if (vars.contains(i))
_arg_returned.set(i);
}
_return_local = _return_local && !(vars.contains_unknown() || vars.contains_allocated());
_return_allocated = _return_allocated && vars.contains_allocated() && !(vars.contains_unknown() || vars.contains_vars());
}
// return true if any element of vars is an argument
bool BCEscapeAnalyzer::is_argument(ArgumentMap vars) {
for (int i = 0; i < _arg_size; i++) {
if (vars.contains(i))
return true;
}
return false;
}
// return true if any element of vars is an arg_stack argument
bool BCEscapeAnalyzer::is_arg_stack(ArgumentMap vars){
if (_conservative)
return true;
for (int i = 0; i < _arg_size; i++) {
if (vars.contains(i) && _arg_stack.test(i))
return true;
}
return false;
}
// return true if all argument elements of vars are returned
bool BCEscapeAnalyzer::returns_all(ArgumentMap vars) {
for (int i = 0; i < _arg_size; i++) {
if (vars.contains(i) && !_arg_returned.test(i)) {
return false;
}
}
return true;
}
void BCEscapeAnalyzer::clear_bits(ArgumentMap vars, VectorSet &bm) {
for (int i = 0; i < _arg_size; i++) {
if (vars.contains(i)) {
bm.remove(i);
}
}
}
void BCEscapeAnalyzer::set_method_escape(ArgumentMap vars) {
clear_bits(vars, _arg_local);
if (vars.contains_allocated()) {
_allocated_escapes = true;
}
}
void BCEscapeAnalyzer::set_global_escape(ArgumentMap vars, bool merge) {
clear_bits(vars, _arg_local);
clear_bits(vars, _arg_stack);
if (vars.contains_allocated())
_allocated_escapes = true;
if (merge && !vars.is_empty()) {
// Merge new state into already processed block.
// New state is not taken into account and
// it may invalidate set_returned() result.
if (vars.contains_unknown() || vars.contains_allocated()) {
_return_local = false;
}
if (vars.contains_unknown() || vars.contains_vars()) {
_return_allocated = false;
}
if (_return_local && vars.contains_vars() && !returns_all(vars)) {
// Return result should be invalidated if args in new
// state are not recorded in return state.
_return_local = false;
}
}
}
void BCEscapeAnalyzer::set_dirty(ArgumentMap vars) {
clear_bits(vars, _dirty);
}
void BCEscapeAnalyzer::set_modified(ArgumentMap vars, int offs, int size) {
for (int i = 0; i < _arg_size; i++) {
if (vars.contains(i)) {
set_arg_modified(i, offs, size);
}
}
if (vars.contains_unknown())
_unknown_modified = true;
}
bool BCEscapeAnalyzer::is_recursive_call(ciMethod* callee) {
for (BCEscapeAnalyzer* scope = this; scope != NULL; scope = scope->_parent) {
if (scope->method() == callee) {
return true;
}
}
return false;
}
bool BCEscapeAnalyzer::is_arg_modified(int arg, int offset, int size_in_bytes) {
if (offset == OFFSET_ANY)
return _arg_modified[arg] != 0;
assert(arg >= 0 && arg < _arg_size, "must be an argument.");
bool modified = false;
int l = offset / HeapWordSize;
int h = align_up(offset + size_in_bytes, HeapWordSize) / HeapWordSize;
if (l > ARG_OFFSET_MAX)
l = ARG_OFFSET_MAX;
if (h > ARG_OFFSET_MAX+1)
h = ARG_OFFSET_MAX + 1;
for (int i = l; i < h; i++) {
modified = modified || (_arg_modified[arg] & (1 << i)) != 0;
}
return modified;
}
void BCEscapeAnalyzer::set_arg_modified(int arg, int offset, int size_in_bytes) {
if (offset == OFFSET_ANY) {
_arg_modified[arg] = (uint) -1;
return;
}
assert(arg >= 0 && arg < _arg_size, "must be an argument.");
int l = offset / HeapWordSize;
int h = align_up(offset + size_in_bytes, HeapWordSize) / HeapWordSize;
if (l > ARG_OFFSET_MAX)
l = ARG_OFFSET_MAX;
if (h > ARG_OFFSET_MAX+1)
h = ARG_OFFSET_MAX + 1;
for (int i = l; i < h; i++) {
_arg_modified[arg] |= (1 << i);
}
}
void BCEscapeAnalyzer::invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder) {
int i;
// retrieve information about the callee
ciInstanceKlass* klass = target->holder();
ciInstanceKlass* calling_klass = method()->holder();
ciInstanceKlass* callee_holder = ciEnv::get_instance_klass_for_declared_method_holder(holder);
ciInstanceKlass* actual_recv = callee_holder;
// Some methods are obviously bindable without any type checks so
// convert them directly to an invokespecial or invokestatic.
if (target->is_loaded() && !target->is_abstract() && target->can_be_statically_bound()) {
switch (code) {
case Bytecodes::_invokevirtual:
code = Bytecodes::_invokespecial;
break;
case Bytecodes::_invokehandle:
code = target->is_static() ? Bytecodes::_invokestatic : Bytecodes::_invokespecial;
break;
default:
break;
}
}
// compute size of arguments
int arg_size = target->invoke_arg_size(code);
int arg_base = MAX2(state._stack_height - arg_size, 0);
// direct recursive calls are skipped if they can be bound statically without introducing
// dependencies and if parameters are passed at the same position as in the current method
// other calls are skipped if there are no unescaped arguments passed to them
bool directly_recursive = (method() == target) &&
(code != Bytecodes::_invokevirtual || target->is_final_method() || state._stack[arg_base] .is_empty());
// check if analysis of callee can safely be skipped
bool skip_callee = true;
for (i = state._stack_height - 1; i >= arg_base && skip_callee; i--) {
ArgumentMap arg = state._stack[i];
skip_callee = !is_argument(arg) || !is_arg_stack(arg) || (directly_recursive && arg.is_singleton(i - arg_base));
}
// For now we conservatively skip invokedynamic.
if (code == Bytecodes::_invokedynamic) {
skip_callee = true;
}
if (skip_callee) {
TRACE_BCEA(3, tty->print_cr("[EA] skipping method %s::%s", holder->name()->as_utf8(), target->name()->as_utf8()));
for (i = 0; i < arg_size; i++) {
set_method_escape(state.raw_pop());
}
_unknown_modified = true; // assume the worst since we don't analyze the called method
return;
}
// determine actual method (use CHA if necessary)
ciMethod* inline_target = NULL;
if (target->is_loaded() && klass->is_loaded()
&& (klass->is_initialized() || (klass->is_interface() && target->holder()->is_initialized()))
&& target->is_loaded()) {
if (code == Bytecodes::_invokestatic
|| code == Bytecodes::_invokespecial
|| (code == Bytecodes::_invokevirtual && target->is_final_method())) {
inline_target = target;
} else {
inline_target = target->find_monomorphic_target(calling_klass, callee_holder, actual_recv);
}
}
if (inline_target != NULL && !is_recursive_call(inline_target)) {
// analyze callee
BCEscapeAnalyzer analyzer(inline_target, this);
// adjust escape state of actual parameters
bool must_record_dependencies = false;
for (i = arg_size - 1; i >= 0; i--) {
ArgumentMap arg = state.raw_pop();
// Check if callee arg is a caller arg or an allocated object
bool allocated = arg.contains_allocated();
if (!(is_argument(arg) || allocated))
continue;
for (int j = 0; j < _arg_size; j++) {
if (arg.contains(j)) {
_arg_modified[j] |= analyzer._arg_modified[i];
}
}
if (!(is_arg_stack(arg) || allocated)) {
// arguments have already been recognized as escaping
} else if (analyzer.is_arg_stack(i) && !analyzer.is_arg_returned(i)) {
set_method_escape(arg);
must_record_dependencies = true;
} else {
set_global_escape(arg);
}
}
_unknown_modified = _unknown_modified || analyzer.has_non_arg_side_affects();
// record dependencies if at least one parameter retained stack-allocatable
if (must_record_dependencies) {
if (code == Bytecodes::_invokeinterface ||
(code == Bytecodes::_invokevirtual && !target->is_final_method())) {
_dependencies.append(actual_recv);
_dependencies.append(inline_target);
}
_dependencies.appendAll(analyzer.dependencies());
}
} else {
TRACE_BCEA(1, tty->print_cr("[EA] virtual method %s is not monomorphic.",
target->name()->as_utf8()));
// conservatively mark all actual parameters as escaping globally
for (i = 0; i < arg_size; i++) {
ArgumentMap arg = state.raw_pop();
if (!is_argument(arg))
continue;
set_modified(arg, OFFSET_ANY, type2size[T_INT]*HeapWordSize);
set_global_escape(arg);
}
_unknown_modified = true; // assume the worst since we don't know the called method
}
}
bool BCEscapeAnalyzer::contains(uint arg_set1, uint arg_set2) {
return ((~arg_set1) | arg_set2) == 0;
}
void BCEscapeAnalyzer::iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray<ciBlock *> &successors) {
blk->set_processed();
ciBytecodeStream s(method());
int limit_bci = blk->limit_bci();
bool fall_through = false;
ArgumentMap allocated_obj;
allocated_obj.add_allocated();
ArgumentMap unknown_obj;
unknown_obj.add_unknown();
ArgumentMap empty_map;
s.reset_to_bci(blk->start_bci());
while (s.next() != ciBytecodeStream::EOBC() && s.cur_bci() < limit_bci) {
fall_through = true;
switch (s.cur_bc()) {
case Bytecodes::_nop:
break;
case Bytecodes::_aconst_null:
state.apush(unknown_obj);
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:
state.spush();
break;
case Bytecodes::_lconst_0:
case Bytecodes::_lconst_1:
case Bytecodes::_dconst_0:
case Bytecodes::_dconst_1:
state.lpush();
break;
case Bytecodes::_ldc:
case Bytecodes::_ldc_w:
case Bytecodes::_ldc2_w:
{
// Avoid calling get_constant() which will try to allocate
// unloaded constant. We need only constant's type.
int index = s.get_constant_pool_index();
constantTag tag = s.get_constant_pool_tag(index);
if (tag.is_long() || tag.is_double()) {
// Only longs and doubles use 2 stack slots.
state.lpush();
} else if (tag.basic_type() == T_OBJECT) {
state.apush(unknown_obj);
} else {
state.spush();
}
break;
}
case Bytecodes::_aload:
state.apush(state._vars[s.get_index()]);
break;
case Bytecodes::_iload:
case Bytecodes::_fload:
case Bytecodes::_iload_0:
case Bytecodes::_iload_1:
case Bytecodes::_iload_2:
case Bytecodes::_iload_3:
case Bytecodes::_fload_0:
case Bytecodes::_fload_1:
case Bytecodes::_fload_2:
case Bytecodes::_fload_3:
state.spush();
break;
case Bytecodes::_lload:
case Bytecodes::_dload:
case Bytecodes::_lload_0:
case Bytecodes::_lload_1:
case Bytecodes::_lload_2:
case Bytecodes::_lload_3:
case Bytecodes::_dload_0:
case Bytecodes::_dload_1:
case Bytecodes::_dload_2:
case Bytecodes::_dload_3:
state.lpush();
break;
case Bytecodes::_aload_0:
state.apush(state._vars[0]);
break;
case Bytecodes::_aload_1:
state.apush(state._vars[1]);
break;
case Bytecodes::_aload_2:
state.apush(state._vars[2]);
break;
case Bytecodes::_aload_3:
state.apush(state._vars[3]);
break;
case Bytecodes::_iaload:
case Bytecodes::_faload:
case Bytecodes::_baload:
case Bytecodes::_caload:
case Bytecodes::_saload:
state.spop();
set_method_escape(state.apop());
state.spush();
break;
case Bytecodes::_laload:
case Bytecodes::_daload:
state.spop();
set_method_escape(state.apop());
state.lpush();
break;
case Bytecodes::_aaload:
{ state.spop();
ArgumentMap array = state.apop();
set_method_escape(array);
state.apush(unknown_obj);
set_dirty(array);
}
break;
case Bytecodes::_istore:
case Bytecodes::_fstore:
case Bytecodes::_istore_0:
case Bytecodes::_istore_1:
case Bytecodes::_istore_2:
case Bytecodes::_istore_3:
case Bytecodes::_fstore_0:
case Bytecodes::_fstore_1:
case Bytecodes::_fstore_2:
case Bytecodes::_fstore_3:
state.spop();
break;
case Bytecodes::_lstore:
case Bytecodes::_dstore:
case Bytecodes::_lstore_0:
case Bytecodes::_lstore_1:
case Bytecodes::_lstore_2:
case Bytecodes::_lstore_3:
case Bytecodes::_dstore_0:
case Bytecodes::_dstore_1:
case Bytecodes::_dstore_2:
case Bytecodes::_dstore_3:
state.lpop();
break;
case Bytecodes::_astore:
state._vars[s.get_index()] = state.apop();
break;
case Bytecodes::_astore_0:
state._vars[0] = state.apop();
break;
case Bytecodes::_astore_1:
state._vars[1] = state.apop();
break;
case Bytecodes::_astore_2:
state._vars[2] = state.apop();
break;
case Bytecodes::_astore_3:
state._vars[3] = state.apop();
break;
case Bytecodes::_iastore:
case Bytecodes::_fastore:
case Bytecodes::_bastore:
case Bytecodes::_castore:
case Bytecodes::_sastore:
{
state.spop();
state.spop();
ArgumentMap arr = state.apop();
set_method_escape(arr);
set_modified(arr, OFFSET_ANY, type2size[T_INT]*HeapWordSize);
break;
}
case Bytecodes::_lastore:
case Bytecodes::_dastore:
{
state.lpop();
state.spop();
ArgumentMap arr = state.apop();
set_method_escape(arr);
set_modified(arr, OFFSET_ANY, type2size[T_LONG]*HeapWordSize);
break;
}
case Bytecodes::_aastore:
{
set_global_escape(state.apop());
state.spop();
ArgumentMap arr = state.apop();
set_modified(arr, OFFSET_ANY, type2size[T_OBJECT]*HeapWordSize);
break;
}
case Bytecodes::_pop:
state.raw_pop();
break;
case Bytecodes::_pop2:
state.raw_pop();
state.raw_pop();
break;
case Bytecodes::_dup:
{ ArgumentMap w1 = state.raw_pop();
state.raw_push(w1);
state.raw_push(w1);
}
break;
case Bytecodes::_dup_x1:
{ ArgumentMap w1 = state.raw_pop();
ArgumentMap w2 = state.raw_pop();
state.raw_push(w1);
state.raw_push(w2);
state.raw_push(w1);
}
break;
case Bytecodes::_dup_x2:
{ ArgumentMap w1 = state.raw_pop();
ArgumentMap w2 = state.raw_pop();
ArgumentMap w3 = state.raw_pop();
state.raw_push(w1);
state.raw_push(w3);
state.raw_push(w2);
state.raw_push(w1);
}
break;
case Bytecodes::_dup2:
{ ArgumentMap w1 = state.raw_pop();
ArgumentMap w2 = state.raw_pop();
state.raw_push(w2);
state.raw_push(w1);
state.raw_push(w2);
state.raw_push(w1);
}
break;
case Bytecodes::_dup2_x1:
{ ArgumentMap w1 = state.raw_pop();
ArgumentMap w2 = state.raw_pop();
ArgumentMap w3 = state.raw_pop();
state.raw_push(w2);
state.raw_push(w1);
state.raw_push(w3);
state.raw_push(w2);
state.raw_push(w1);
}
break;
case Bytecodes::_dup2_x2:
{ ArgumentMap w1 = state.raw_pop();
ArgumentMap w2 = state.raw_pop();
ArgumentMap w3 = state.raw_pop();
ArgumentMap w4 = state.raw_pop();
state.raw_push(w2);
state.raw_push(w1);
state.raw_push(w4);
state.raw_push(w3);
state.raw_push(w2);
state.raw_push(w1);
}
break;
case Bytecodes::_swap:
{ ArgumentMap w1 = state.raw_pop();
ArgumentMap w2 = state.raw_pop();
state.raw_push(w1);
state.raw_push(w2);
}
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::_iand:
case Bytecodes::_ior:
case Bytecodes::_ixor:
state.spop();
state.spop();
state.spush();
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:
state.lpop();
state.lpop();
state.lpush();
break;
case Bytecodes::_ishl:
case Bytecodes::_ishr:
case Bytecodes::_iushr:
state.spop();
state.spop();
state.spush();
break;
case Bytecodes::_lshl:
case Bytecodes::_lshr:
case Bytecodes::_lushr:
state.spop();
state.lpop();
state.lpush();
break;
case Bytecodes::_ineg:
case Bytecodes::_fneg:
state.spop();
state.spush();
break;
case Bytecodes::_lneg:
case Bytecodes::_dneg:
state.lpop();
state.lpush();
break;
case Bytecodes::_iinc:
break;
case Bytecodes::_i2l:
case Bytecodes::_i2d:
case Bytecodes::_f2l:
case Bytecodes::_f2d:
state.spop();
state.lpush();
break;
case Bytecodes::_i2f:
case Bytecodes::_f2i:
state.spop();
state.spush();
break;
case Bytecodes::_l2i:
case Bytecodes::_l2f:
case Bytecodes::_d2i:
case Bytecodes::_d2f:
state.lpop();
state.spush();
break;
case Bytecodes::_l2d:
case Bytecodes::_d2l:
state.lpop();
state.lpush();
break;
case Bytecodes::_i2b:
case Bytecodes::_i2c:
case Bytecodes::_i2s:
state.spop();
state.spush();
break;
case Bytecodes::_lcmp:
case Bytecodes::_dcmpl:
case Bytecodes::_dcmpg:
state.lpop();
state.lpop();
state.spush();
break;
case Bytecodes::_fcmpl:
case Bytecodes::_fcmpg:
state.spop();
state.spop();
state.spush();
break;
case Bytecodes::_ifeq:
case Bytecodes::_ifne:
case Bytecodes::_iflt:
case Bytecodes::_ifge:
case Bytecodes::_ifgt:
case Bytecodes::_ifle:
{
state.spop();
int dest_bci = s.get_dest();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
assert(s.next_bci() == limit_bci, "branch must end block");
successors.push(_methodBlocks->block_containing(dest_bci));
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:
{
state.spop();
state.spop();
int dest_bci = s.get_dest();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
assert(s.next_bci() == limit_bci, "branch must end block");
successors.push(_methodBlocks->block_containing(dest_bci));
break;
}
case Bytecodes::_if_acmpeq:
case Bytecodes::_if_acmpne:
{
set_method_escape(state.apop());
set_method_escape(state.apop());
int dest_bci = s.get_dest();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
assert(s.next_bci() == limit_bci, "branch must end block");
successors.push(_methodBlocks->block_containing(dest_bci));
break;
}
case Bytecodes::_goto:
{
int dest_bci = s.get_dest();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
assert(s.next_bci() == limit_bci, "branch must end block");
successors.push(_methodBlocks->block_containing(dest_bci));
fall_through = false;
break;
}
case Bytecodes::_jsr:
{
int dest_bci = s.get_dest();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
assert(s.next_bci() == limit_bci, "branch must end block");
state.apush(empty_map);
successors.push(_methodBlocks->block_containing(dest_bci));
fall_through = false;
break;
}
case Bytecodes::_ret:
// we don't track the destination of a "ret" instruction
assert(s.next_bci() == limit_bci, "branch must end block");
fall_through = false;
break;
case Bytecodes::_return:
assert(s.next_bci() == limit_bci, "return must end block");
fall_through = false;
break;
case Bytecodes::_tableswitch:
{
state.spop();
Bytecode_tableswitch sw(&s);
int len = sw.length();
int dest_bci;
for (int i = 0; i < len; i++) {
dest_bci = s.cur_bci() + sw.dest_offset_at(i);
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
successors.push(_methodBlocks->block_containing(dest_bci));
}
dest_bci = s.cur_bci() + sw.default_offset();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
successors.push(_methodBlocks->block_containing(dest_bci));
assert(s.next_bci() == limit_bci, "branch must end block");
fall_through = false;
break;
}
case Bytecodes::_lookupswitch:
{
state.spop();
Bytecode_lookupswitch sw(&s);
int len = sw.number_of_pairs();
int dest_bci;
for (int i = 0; i < len; i++) {
dest_bci = s.cur_bci() + sw.pair_at(i).offset();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
successors.push(_methodBlocks->block_containing(dest_bci));
}
dest_bci = s.cur_bci() + sw.default_offset();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
successors.push(_methodBlocks->block_containing(dest_bci));
fall_through = false;
break;
}
case Bytecodes::_ireturn:
case Bytecodes::_freturn:
state.spop();
fall_through = false;
break;
case Bytecodes::_lreturn:
case Bytecodes::_dreturn:
state.lpop();
fall_through = false;
break;
case Bytecodes::_areturn:
set_returned(state.apop());
fall_through = false;
break;
case Bytecodes::_getstatic:
case Bytecodes::_getfield:
{ bool ignored_will_link;
ciField* field = s.get_field(ignored_will_link);
BasicType field_type = field->type()->basic_type();
if (s.cur_bc() != Bytecodes::_getstatic) {
set_method_escape(state.apop());
}
if (is_reference_type(field_type)) {
state.apush(unknown_obj);
} else if (type2size[field_type] == 1) {
state.spush();
} else {
state.lpush();
}
}
break;
case Bytecodes::_putstatic:
case Bytecodes::_putfield:
{ bool will_link;
ciField* field = s.get_field(will_link);
BasicType field_type = field->type()->basic_type();
if (is_reference_type(field_type)) {
set_global_escape(state.apop());
} else if (type2size[field_type] == 1) {
state.spop();
} else {
state.lpop();
}
if (s.cur_bc() != Bytecodes::_putstatic) {
ArgumentMap p = state.apop();
set_method_escape(p);
set_modified(p, will_link ? field->offset() : OFFSET_ANY, type2size[field_type]*HeapWordSize);
}
}
break;
case Bytecodes::_invokevirtual:
case Bytecodes::_invokespecial:
case Bytecodes::_invokestatic:
case Bytecodes::_invokedynamic:
case Bytecodes::_invokeinterface:
{ bool ignored_will_link;
ciSignature* declared_signature = NULL;
ciMethod* target = s.get_method(ignored_will_link, &declared_signature);
ciKlass* holder = s.get_declared_method_holder();
assert(declared_signature != NULL, "cannot be null");
// If the current bytecode has an attached appendix argument,
// push an unknown object to represent that argument. (Analysis
// of dynamic call sites, especially invokehandle calls, needs
// the appendix argument on the stack, in addition to "regular" arguments
// pushed onto the stack by bytecode instructions preceding the call.)
//
// The escape analyzer does _not_ use the ciBytecodeStream::has_appendix(s)
// method to determine whether the current bytecode has an appendix argument.
// The has_appendix() method obtains the appendix from the
// ConstantPoolCacheEntry::_f1 field, which can happen concurrently with
// resolution of dynamic call sites. Callees in the
// ciBytecodeStream::get_method() call above also access the _f1 field;
// interleaving the get_method() and has_appendix() calls in the current
// method with call site resolution can lead to an inconsistent view of
// the current method's argument count. In particular, some interleaving(s)
// can cause the method's argument count to not include the appendix, which
// then leads to stack over-/underflow in the escape analyzer.
//
// Instead of pushing the argument if has_appendix() is true, the escape analyzer
// pushes an appendix for all call sites targeted by invokedynamic and invokehandle
// instructions, except if the call site is the _invokeBasic intrinsic
// (that intrinsic is always targeted by an invokehandle instruction but does
// not have an appendix argument).
if (target->is_loaded() &&
Bytecodes::has_optional_appendix(s.cur_bc_raw()) &&
target->intrinsic_id() != vmIntrinsics::_invokeBasic) {
state.apush(unknown_obj);
}
// Pass in raw bytecode because we need to see invokehandle instructions.
invoke(state, s.cur_bc_raw(), target, holder);
// We are using the return type of the declared signature here because
// it might be a more concrete type than the one from the target (for
// e.g. invokedynamic and invokehandle).
ciType* return_type = declared_signature->return_type();
if (!return_type->is_primitive_type()) {
state.apush(unknown_obj);
} else if (return_type->is_one_word()) {
state.spush();
} else if (return_type->is_two_word()) {
state.lpush();
}
}
break;
case Bytecodes::_new:
state.apush(allocated_obj);
break;
case Bytecodes::_newarray:
case Bytecodes::_anewarray:
state.spop();
state.apush(allocated_obj);
break;
case Bytecodes::_multianewarray:
{ int i = s.cur_bcp()[3];
while (i-- > 0) state.spop();
state.apush(allocated_obj);
}
break;
case Bytecodes::_arraylength:
set_method_escape(state.apop());
state.spush();
break;
case Bytecodes::_athrow:
set_global_escape(state.apop());
fall_through = false;
break;
case Bytecodes::_checkcast:
{ ArgumentMap obj = state.apop();
set_method_escape(obj);
state.apush(obj);
}
break;
case Bytecodes::_instanceof:
set_method_escape(state.apop());
state.spush();
break;
case Bytecodes::_monitorenter:
case Bytecodes::_monitorexit:
state.apop();
break;
case Bytecodes::_wide:
ShouldNotReachHere();
break;
case Bytecodes::_ifnull:
case Bytecodes::_ifnonnull:
{
set_method_escape(state.apop());
int dest_bci = s.get_dest();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
assert(s.next_bci() == limit_bci, "branch must end block");
successors.push(_methodBlocks->block_containing(dest_bci));
break;
}
case Bytecodes::_goto_w:
{
int dest_bci = s.get_far_dest();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
assert(s.next_bci() == limit_bci, "branch must end block");
successors.push(_methodBlocks->block_containing(dest_bci));
fall_through = false;
break;
}
case Bytecodes::_jsr_w:
{
int dest_bci = s.get_far_dest();
assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
assert(s.next_bci() == limit_bci, "branch must end block");
state.apush(empty_map);
successors.push(_methodBlocks->block_containing(dest_bci));
fall_through = false;
break;
}
case Bytecodes::_breakpoint:
break;
default:
ShouldNotReachHere();
break;
}
}
if (fall_through) {
int fall_through_bci = s.cur_bci();
if (fall_through_bci < _method->code_size()) {
assert(_methodBlocks->is_block_start(fall_through_bci), "must fall through to block start.");
successors.push(_methodBlocks->block_containing(fall_through_bci));
}
}
}
void BCEscapeAnalyzer::merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state) {
StateInfo *d_state = blockstates + dest->index();
int nlocals = _method->max_locals();
// exceptions may cause transfer of control to handlers in the middle of a
// block, so we don't merge the incoming state of exception handlers
if (dest->is_handler())
return;
if (!d_state->_initialized ) {
// destination not initialized, just copy
for (int i = 0; i < nlocals; i++) {
d_state->_vars[i] = s_state->_vars[i];
}
for (int i = 0; i < s_state->_stack_height; i++) {
d_state->_stack[i] = s_state->_stack[i];
}
d_state->_stack_height = s_state->_stack_height;
d_state->_max_stack = s_state->_max_stack;
d_state->_initialized = true;
} else if (!dest->processed()) {
// we have not yet walked the bytecodes of dest, we can merge
// the states
assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
for (int i = 0; i < nlocals; i++) {
d_state->_vars[i].set_union(s_state->_vars[i]);
}
for (int i = 0; i < s_state->_stack_height; i++) {
d_state->_stack[i].set_union(s_state->_stack[i]);
}
} else {
// the bytecodes of dest have already been processed, mark any
// arguments in the source state which are not in the dest state
// as global escape.
// Future refinement: we only need to mark these variable to the
// maximum escape of any variables in dest state
assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
ArgumentMap extra_vars;
for (int i = 0; i < nlocals; i++) {
ArgumentMap t;
t = s_state->_vars[i];
t.set_difference(d_state->_vars[i]);
extra_vars.set_union(t);
}
for (int i = 0; i < s_state->_stack_height; i++) {
ArgumentMap t;
//extra_vars |= !d_state->_vars[i] & s_state->_vars[i];
t.clear();
t = s_state->_stack[i];
t.set_difference(d_state->_stack[i]);
extra_vars.set_union(t);
}
set_global_escape(extra_vars, true);
}
}
void BCEscapeAnalyzer::iterate_blocks(Arena *arena) {
int numblocks = _methodBlocks->num_blocks();
int stkSize = _method->max_stack();
int numLocals = _method->max_locals();
StateInfo state;
int datacount = (numblocks + 1) * (stkSize + numLocals);
int datasize = datacount * sizeof(ArgumentMap);
StateInfo *blockstates = (StateInfo *) arena->Amalloc(numblocks * sizeof(StateInfo));
ArgumentMap *statedata = (ArgumentMap *) arena->Amalloc(datasize);
for (int i = 0; i < datacount; i++) ::new ((void*)&statedata[i]) ArgumentMap();
ArgumentMap *dp = statedata;
state._vars = dp;
dp += numLocals;
state._stack = dp;
dp += stkSize;
state._initialized = false;
state._max_stack = stkSize;
for (int i = 0; i < numblocks; i++) {
blockstates[i]._vars = dp;
dp += numLocals;
blockstates[i]._stack = dp;
dp += stkSize;
blockstates[i]._initialized = false;
blockstates[i]._stack_height = 0;
blockstates[i]._max_stack = stkSize;
}
GrowableArray<ciBlock *> worklist(arena, numblocks / 4, 0, NULL);
GrowableArray<ciBlock *> successors(arena, 4, 0, NULL);
_methodBlocks->clear_processed();
// initialize block 0 state from method signature
ArgumentMap allVars; // all oop arguments to method
ciSignature* sig = method()->signature();
int j = 0;
ciBlock* first_blk = _methodBlocks->block_containing(0);
int fb_i = first_blk->index();
if (!method()->is_static()) {
// record information for "this"
blockstates[fb_i]._vars[j].set(j);
allVars.add(j);
j++;
}
for (int i = 0; i < sig->count(); i++) {
ciType* t = sig->type_at(i);
if (!t->is_primitive_type()) {
blockstates[fb_i]._vars[j].set(j);
allVars.add(j);
}
j += t->size();
}
blockstates[fb_i]._initialized = true;
assert(j == _arg_size, "just checking");
ArgumentMap unknown_map;
unknown_map.add_unknown();
worklist.push(first_blk);
while(worklist.length() > 0) {
ciBlock *blk = worklist.pop();
StateInfo *blkState = blockstates + blk->index();
if (blk->is_handler() || blk->is_ret_target()) {
// for an exception handler or a target of a ret instruction, we assume the worst case,
// that any variable could contain any argument
for (int i = 0; i < numLocals; i++) {
state._vars[i] = allVars;
}
if (blk->is_handler()) {
state._stack_height = 1;
} else {
state._stack_height = blkState->_stack_height;
}
for (int i = 0; i < state._stack_height; i++) {
// ??? should this be unknown_map ???
state._stack[i] = allVars;
}
} else {
for (int i = 0; i < numLocals; i++) {
state._vars[i] = blkState->_vars[i];
}
for (int i = 0; i < blkState->_stack_height; i++) {
state._stack[i] = blkState->_stack[i];
}
state._stack_height = blkState->_stack_height;
}
iterate_one_block(blk, state, successors);
// if this block has any exception handlers, push them
// onto successor list
if (blk->has_handler()) {
DEBUG_ONLY(int handler_count = 0;)
int blk_start = blk->start_bci();
int blk_end = blk->limit_bci();
for (int i = 0; i < numblocks; i++) {
ciBlock *b = _methodBlocks->block(i);
if (b->is_handler()) {
int ex_start = b->ex_start_bci();
int ex_end = b->ex_limit_bci();
if ((ex_start >= blk_start && ex_start < blk_end) ||
(ex_end > blk_start && ex_end <= blk_end)) {
successors.push(b);
}
DEBUG_ONLY(handler_count++;)
}
}
assert(handler_count > 0, "must find at least one handler");
}
// merge computed variable state with successors
while(successors.length() > 0) {
ciBlock *succ = successors.pop();
merge_block_states(blockstates, succ, &state);
if (!succ->processed())
worklist.push(succ);
}
}
}
void BCEscapeAnalyzer::do_analysis() {
Arena* arena = CURRENT_ENV->arena();
// identify basic blocks
_methodBlocks = _method->get_method_blocks();
iterate_blocks(arena);
}
vmIntrinsics::ID BCEscapeAnalyzer::known_intrinsic() {
vmIntrinsics::ID iid = method()->intrinsic_id();
if (iid == vmIntrinsics::_getClass ||
iid == vmIntrinsics::_hashCode) {
return iid;
} else {
return vmIntrinsics::_none;
}
}
void BCEscapeAnalyzer::compute_escape_for_intrinsic(vmIntrinsics::ID iid) {
switch (iid) {
case vmIntrinsics::_getClass:
_return_local = false;
_return_allocated = false;
break;
case vmIntrinsics::_hashCode:
// initialized state is correct
break;
default:
assert(false, "unexpected intrinsic");
}
}
void BCEscapeAnalyzer::initialize() {
int i;
// clear escape information (method may have been deoptimized)
methodData()->clear_escape_info();
// initialize escape state of object parameters
ciSignature* sig = method()->signature();
int j = 0;
if (!method()->is_static()) {
_arg_local.set(0);
_arg_stack.set(0);
j++;
}
for (i = 0; i < sig->count(); i++) {
ciType* t = sig->type_at(i);
if (!t->is_primitive_type()) {
_arg_local.set(j);
_arg_stack.set(j);
}
j += t->size();
}
assert(j == _arg_size, "just checking");
// start with optimistic assumption
ciType *rt = _method->return_type();
if (rt->is_primitive_type()) {
_return_local = false;
_return_allocated = false;
} else {
_return_local = true;
_return_allocated = true;
}
_allocated_escapes = false;
_unknown_modified = false;
}
void BCEscapeAnalyzer::clear_escape_info() {
ciSignature* sig = method()->signature();
int arg_count = sig->count();
ArgumentMap var;
if (!method()->is_static()) {
arg_count++; // allow for "this"
}
for (int i = 0; i < arg_count; i++) {
set_arg_modified(i, OFFSET_ANY, 4);
var.clear();
var.set(i);
set_modified(var, OFFSET_ANY, 4);
set_global_escape(var);
}
_arg_local.clear();
_arg_stack.clear();
_arg_returned.clear();
_return_local = false;
_return_allocated = false;
_allocated_escapes = true;
_unknown_modified = true;
}
void BCEscapeAnalyzer::compute_escape_info() {
int i;
assert(!methodData()->has_escape_info(), "do not overwrite escape info");
vmIntrinsics::ID iid = known_intrinsic();
// check if method can be analyzed
if (iid == vmIntrinsics::_none && (method()->is_abstract() || method()->is_native() || !method()->holder()->is_initialized()
|| _level > MaxBCEAEstimateLevel
|| method()->code_size() > MaxBCEAEstimateSize)) {
if (BCEATraceLevel >= 1) {
tty->print("Skipping method because: ");
if (method()->is_abstract())
tty->print_cr("method is abstract.");
else if (method()->is_native())
tty->print_cr("method is native.");
else if (!method()->holder()->is_initialized())
tty->print_cr("class of method is not initialized.");
else if (_level > MaxBCEAEstimateLevel)
tty->print_cr("level (%d) exceeds MaxBCEAEstimateLevel (%d).",
_level, (int) MaxBCEAEstimateLevel);
else if (method()->code_size() > MaxBCEAEstimateSize)
tty->print_cr("code size (%d) exceeds MaxBCEAEstimateSize (%d).",
method()->code_size(), (int) MaxBCEAEstimateSize);
else
ShouldNotReachHere();
}
clear_escape_info();
return;
}
if (BCEATraceLevel >= 1) {
tty->print("[EA] estimating escape information for");
if (iid != vmIntrinsics::_none)
tty->print(" intrinsic");
method()->print_short_name();
tty->print_cr(" (%d bytes)", method()->code_size());
}
initialize();
// Do not scan method if it has no object parameters and
// does not returns an object (_return_allocated is set in initialize()).
if (_arg_local.is_empty() && !_return_allocated) {
// Clear all info since method's bytecode was not analysed and
// set pessimistic escape information.
clear_escape_info();
methodData()->set_eflag(MethodData::allocated_escapes);
methodData()->set_eflag(MethodData::unknown_modified);
methodData()->set_eflag(MethodData::estimated);
return;
}
if (iid != vmIntrinsics::_none)
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