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jdk-24/hotspot/src/share/vm/c1/c1_RangeCheckElimination.cpp
David Chase 305ec3bd3f 8037816: Fix for 8036122 breaks build with Xcode5/clang 
Repaired or selectively disabled offending formats; future-proofed with additional checking

Reviewed-by: kvn, jrose, stefank
2014-05-09 16:50:54 -04:00

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/*
* Copyright (c) 2012, 2014, 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 "c1/c1_ValueStack.hpp"
#include "c1/c1_RangeCheckElimination.hpp"
#include "c1/c1_IR.hpp"
#include "c1/c1_Canonicalizer.hpp"
#include "c1/c1_ValueMap.hpp"
#include "ci/ciMethodData.hpp"
#include "runtime/deoptimization.hpp"
// Macros for the Trace and the Assertion flag
#ifdef ASSERT
#define TRACE_RANGE_CHECK_ELIMINATION(code) if (TraceRangeCheckElimination) { code; }
#define ASSERT_RANGE_CHECK_ELIMINATION(code) if (AssertRangeCheckElimination) { code; }
#define TRACE_OR_ASSERT_RANGE_CHECK_ELIMINATION(code) if (TraceRangeCheckElimination || AssertRangeCheckElimination) { code; }
#else
#define TRACE_RANGE_CHECK_ELIMINATION(code)
#define ASSERT_RANGE_CHECK_ELIMINATION(code)
#define TRACE_OR_ASSERT_RANGE_CHECK_ELIMINATION(code)
#endif
// Entry point for the optimization
void RangeCheckElimination::eliminate(IR *ir) {
bool do_elimination = ir->compilation()->has_access_indexed();
ASSERT_RANGE_CHECK_ELIMINATION(do_elimination = true);
if (do_elimination) {
RangeCheckEliminator rce(ir);
}
}
// Constructor
RangeCheckEliminator::RangeCheckEliminator(IR *ir) :
_bounds(Instruction::number_of_instructions(), NULL),
_access_indexed_info(Instruction::number_of_instructions(), NULL)
{
_visitor.set_range_check_eliminator(this);
_ir = ir;
_number_of_instructions = Instruction::number_of_instructions();
_optimistic = ir->compilation()->is_optimistic();
TRACE_RANGE_CHECK_ELIMINATION(
tty->cr();
tty->print_cr("Range check elimination");
ir->method()->print_name(tty);
tty->cr();
);
TRACE_RANGE_CHECK_ELIMINATION(
tty->print_cr("optimistic=%d", (int)_optimistic);
);
#ifdef ASSERT
// Verifies several conditions that must be true on the IR-input. Only used for debugging purposes.
TRACE_RANGE_CHECK_ELIMINATION(
tty->print_cr("Verification of IR . . .");
);
Verification verification(ir);
#endif
// Set process block flags
// Optimization so a blocks is only processed if it contains an access indexed instruction or if
// one of its children in the dominator tree contains an access indexed instruction.
set_process_block_flags(ir->start());
// Pass over instructions in the dominator tree
TRACE_RANGE_CHECK_ELIMINATION(
tty->print_cr("Starting pass over dominator tree . . .")
);
calc_bounds(ir->start(), NULL);
TRACE_RANGE_CHECK_ELIMINATION(
tty->print_cr("Finished!")
);
}
// Instruction specific work for some instructions
// Constant
void RangeCheckEliminator::Visitor::do_Constant(Constant *c) {
IntConstant *ic = c->type()->as_IntConstant();
if (ic != NULL) {
int value = ic->value();
_bound = new Bound(value, NULL, value, NULL);
}
}
// LogicOp
void RangeCheckEliminator::Visitor::do_LogicOp(LogicOp *lo) {
if (lo->type()->as_IntType() && lo->op() == Bytecodes::_iand && (lo->x()->as_Constant() || lo->y()->as_Constant())) {
int constant = 0;
Constant *c = lo->x()->as_Constant();
if (c != NULL) {
constant = c->type()->as_IntConstant()->value();
} else {
constant = lo->y()->as_Constant()->type()->as_IntConstant()->value();
}
if (constant >= 0) {
_bound = new Bound(0, NULL, constant, NULL);
}
}
}
// Phi
void RangeCheckEliminator::Visitor::do_Phi(Phi *phi) {
if (!phi->type()->as_IntType() && !phi->type()->as_ObjectType()) return;
BlockBegin *block = phi->block();
int op_count = phi->operand_count();
bool has_upper = true;
bool has_lower = true;
assert(phi, "Phi must not be null");
Bound *bound = NULL;
// TODO: support more difficult phis
for (int i=0; i<op_count; i++) {
Value v = phi->operand_at(i);
if (v == phi) continue;
// Check if instruction is connected with phi itself
Op2 *op2 = v->as_Op2();
if (op2 != NULL) {
Value x = op2->x();
Value y = op2->y();
if ((x == phi || y == phi)) {
Value other = x;
if (other == phi) {
other = y;
}
ArithmeticOp *ao = v->as_ArithmeticOp();
if (ao != NULL && ao->op() == Bytecodes::_iadd) {
assert(ao->op() == Bytecodes::_iadd, "Has to be add!");
if (ao->type()->as_IntType()) {
Constant *c = other->as_Constant();
if (c != NULL) {
assert(c->type()->as_IntConstant(), "Constant has to be of type integer");
int value = c->type()->as_IntConstant()->value();
if (value == 1) {
has_upper = false;
} else if (value > 1) {
// Overflow not guaranteed
has_upper = false;
has_lower = false;
} else if (value < 0) {
has_lower = false;
}
continue;
}
}
}
}
}
// No connection -> new bound
Bound *v_bound = _rce->get_bound(v);
Bound *cur_bound;
int cur_constant = 0;
Value cur_value = v;
if (v->type()->as_IntConstant()) {
cur_constant = v->type()->as_IntConstant()->value();
cur_value = NULL;
}
if (!v_bound->has_upper() || !v_bound->has_lower()) {
cur_bound = new Bound(cur_constant, cur_value, cur_constant, cur_value);
} else {
cur_bound = v_bound;
}
if (cur_bound) {
if (!bound) {
bound = cur_bound->copy();
} else {
bound->or_op(cur_bound);
}
} else {
// No bound!
bound = NULL;
break;
}
}
if (bound) {
if (!has_upper) {
bound->remove_upper();
}
if (!has_lower) {
bound->remove_lower();
}
_bound = bound;
} else {
_bound = new Bound();
}
}
// ArithmeticOp
void RangeCheckEliminator::Visitor::do_ArithmeticOp(ArithmeticOp *ao) {
Value x = ao->x();
Value y = ao->y();
if (ao->op() == Bytecodes::_irem) {
Bound* x_bound = _rce->get_bound(x);
Bound* y_bound = _rce->get_bound(y);
if (x_bound->lower() >= 0 && x_bound->lower_instr() == NULL && y->as_ArrayLength() != NULL) {
_bound = new Bound(0, NULL, -1, y);
} else {
_bound = new Bound();
}
} else if (!x->as_Constant() || !y->as_Constant()) {
assert(!x->as_Constant() || !y->as_Constant(), "One of the operands must be non-constant!");
if (((x->as_Constant() || y->as_Constant()) && (ao->op() == Bytecodes::_iadd)) || (y->as_Constant() && ao->op() == Bytecodes::_isub)) {
assert(ao->op() == Bytecodes::_iadd || ao->op() == Bytecodes::_isub, "Operand must be iadd or isub");
if (y->as_Constant()) {
Value tmp = x;
x = y;
y = tmp;
}
assert(x->as_Constant()->type()->as_IntConstant(), "Constant must be int constant!");
// Constant now in x
int const_value = x->as_Constant()->type()->as_IntConstant()->value();
if (ao->op() == Bytecodes::_iadd || const_value != min_jint) {
if (ao->op() == Bytecodes::_isub) {
const_value = -const_value;
}
Bound * bound = _rce->get_bound(y);
if (bound->has_upper() && bound->has_lower()) {
int new_lower = bound->lower() + const_value;
jlong new_lowerl = ((jlong)bound->lower()) + const_value;
int new_upper = bound->upper() + const_value;
jlong new_upperl = ((jlong)bound->upper()) + const_value;
if (((jlong)new_lower) == new_lowerl && ((jlong)new_upper == new_upperl)) {
Bound *newBound = new Bound(new_lower, bound->lower_instr(), new_upper, bound->upper_instr());
_bound = newBound;
} else {
// overflow
_bound = new Bound();
}
} else {
_bound = new Bound();
}
} else {
_bound = new Bound();
}
} else {
Bound *bound = _rce->get_bound(x);
if (ao->op() == Bytecodes::_isub) {
if (bound->lower_instr() == y) {
_bound = new Bound(Instruction::geq, NULL, bound->lower());
} else {
_bound = new Bound();
}
} else {
_bound = new Bound();
}
}
}
}
// IfOp
void RangeCheckEliminator::Visitor::do_IfOp(IfOp *ifOp)
{
if (ifOp->tval()->type()->as_IntConstant() && ifOp->fval()->type()->as_IntConstant()) {
int min = ifOp->tval()->type()->as_IntConstant()->value();
int max = ifOp->fval()->type()->as_IntConstant()->value();
if (min > max) {
// min ^= max ^= min ^= max;
int tmp = min;
min = max;
max = tmp;
}
_bound = new Bound(min, NULL, max, NULL);
}
}
// Get bound. Returns the current bound on Value v. Normally this is the topmost element on the bound stack.
RangeCheckEliminator::Bound *RangeCheckEliminator::get_bound(Value v) {
// Wrong type or NULL -> No bound
if (!v || (!v->type()->as_IntType() && !v->type()->as_ObjectType())) return NULL;
if (!_bounds[v->id()]) {
// First (default) bound is calculated
// Create BoundStack
_bounds[v->id()] = new BoundStack();
_visitor.clear_bound();
Value visit_value = v;
visit_value->visit(&_visitor);
Bound *bound = _visitor.bound();
if (bound) {
_bounds[v->id()]->push(bound);
}
if (_bounds[v->id()]->length() == 0) {
assert(!(v->as_Constant() && v->type()->as_IntConstant()), "constants not handled here");
_bounds[v->id()]->push(new Bound());
}
} else if (_bounds[v->id()]->length() == 0) {
// To avoid endless loops, bound is currently in calculation -> nothing known about it
return new Bound();
}
// Return bound
return _bounds[v->id()]->top();
}
// Update bound
void RangeCheckEliminator::update_bound(IntegerStack &pushed, Value v, Instruction::Condition cond, Value value, int constant) {
if (cond == Instruction::gtr) {
cond = Instruction::geq;
constant++;
} else if (cond == Instruction::lss) {
cond = Instruction::leq;
constant--;
}
Bound *bound = new Bound(cond, value, constant);
update_bound(pushed, v, bound);
}
// Checks for loop invariance. Returns true if the instruction is outside of the loop which is identified by loop_header.
bool RangeCheckEliminator::loop_invariant(BlockBegin *loop_header, Instruction *instruction) {
assert(loop_header, "Loop header must not be null!");
if (!instruction) return true;
return instruction->dominator_depth() < loop_header->dominator_depth();
}
// Update bound. Pushes a new bound onto the stack. Tries to do a conjunction with the current bound.
void RangeCheckEliminator::update_bound(IntegerStack &pushed, Value v, Bound *bound) {
if (v->as_Constant()) {
// No bound update for constants
return;
}
if (!_bounds[v->id()]) {
get_bound(v);
assert(_bounds[v->id()], "Now Stack must exist");
}
Bound *top = NULL;
if (_bounds[v->id()]->length() > 0) {
top = _bounds[v->id()]->top();
}
if (top) {
bound->and_op(top);
}
_bounds[v->id()]->push(bound);
pushed.append(v->id());
}
// Add instruction + idx for in block motion
void RangeCheckEliminator::add_access_indexed_info(InstructionList &indices, int idx, Value instruction, AccessIndexed *ai) {
int id = instruction->id();
AccessIndexedInfo *aii = _access_indexed_info[id];
if (aii == NULL) {
aii = new AccessIndexedInfo();
_access_indexed_info[id] = aii;
indices.append(instruction);
aii->_min = idx;
aii->_max = idx;
aii->_list = new AccessIndexedList();
} else if (idx >= aii->_min && idx <= aii->_max) {
remove_range_check(ai);
return;
}
aii->_min = MIN2(aii->_min, idx);
aii->_max = MAX2(aii->_max, idx);
aii->_list->append(ai);
}
// In block motion. Tries to reorder checks in order to reduce some of them.
// Example:
// a[i] = 0;
// a[i+2] = 0;
// a[i+1] = 0;
// In this example the check for a[i+1] would be considered as unnecessary during the first iteration.
// After this i is only checked once for i >= 0 and i+2 < a.length before the first array access. If this
// check fails, deoptimization is called.
void RangeCheckEliminator::in_block_motion(BlockBegin *block, AccessIndexedList &accessIndexed, InstructionList &arrays) {
InstructionList indices;
// Now iterate over all arrays
for (int i=0; i<arrays.length(); i++) {
int max_constant = -1;
AccessIndexedList list_constant;
Value array = arrays.at(i);
// For all AccessIndexed-instructions in this block concerning the current array.
for(int j=0; j<accessIndexed.length(); j++) {
AccessIndexed *ai = accessIndexed.at(j);
if (ai->array() != array || !ai->check_flag(Instruction::NeedsRangeCheckFlag)) continue;
Value index = ai->index();
Constant *c = index->as_Constant();
if (c != NULL) {
int constant_value = c->type()->as_IntConstant()->value();
if (constant_value >= 0) {
if (constant_value <= max_constant) {
// No range check needed for this
remove_range_check(ai);
} else {
max_constant = constant_value;
list_constant.append(ai);
}
}
} else {
int last_integer = 0;
Instruction *last_instruction = index;
int base = 0;
ArithmeticOp *ao = index->as_ArithmeticOp();
while (ao != NULL && (ao->x()->as_Constant() || ao->y()->as_Constant()) && (ao->op() == Bytecodes::_iadd || ao->op() == Bytecodes::_isub)) {
c = ao->y()->as_Constant();
Instruction *other = ao->x();
if (!c && ao->op() == Bytecodes::_iadd) {
c = ao->x()->as_Constant();
other = ao->y();
}
if (c) {
int value = c->type()->as_IntConstant()->value();
if (value != min_jint) {
if (ao->op() == Bytecodes::_isub) {
value = -value;
}
base += value;
last_integer = base;
last_instruction = other;
}
index = other;
} else {
break;
}
ao = index->as_ArithmeticOp();
}
add_access_indexed_info(indices, last_integer, last_instruction, ai);
}
}
// Iterate over all different indices
if (_optimistic) {
for (int i = 0; i < indices.length(); i++) {
Instruction *index_instruction = indices.at(i);
AccessIndexedInfo *info = _access_indexed_info[index_instruction->id()];
assert(info != NULL, "Info must not be null");
// if idx < 0, max > 0, max + idx may fall between 0 and
// length-1 and if min < 0, min + idx may overflow and be >=
// 0. The predicate wouldn't trigger but some accesses could
// be with a negative index. This test guarantees that for the
// min and max value that are kept the predicate can't let
// some incorrect accesses happen.
bool range_cond = (info->_max < 0 || info->_max + min_jint <= info->_min);
// Generate code only if more than 2 range checks can be eliminated because of that.
// 2 because at least 2 comparisons are done
if (info->_list->length() > 2 && range_cond) {
AccessIndexed *first = info->_list->at(0);
Instruction *insert_position = first->prev();
assert(insert_position->next() == first, "prev was calculated");
ValueStack *state = first->state_before();
// Load min Constant
Constant *min_constant = NULL;
if (info->_min != 0) {
min_constant = new Constant(new IntConstant(info->_min));
NOT_PRODUCT(min_constant->set_printable_bci(first->printable_bci()));
insert_position = insert_position->insert_after(min_constant);
}
// Load max Constant
Constant *max_constant = NULL;
if (info->_max != 0) {
max_constant = new Constant(new IntConstant(info->_max));
NOT_PRODUCT(max_constant->set_printable_bci(first->printable_bci()));
insert_position = insert_position->insert_after(max_constant);
}
// Load array length
Value length_instr = first->length();
if (!length_instr) {
ArrayLength *length = new ArrayLength(array, first->state_before()->copy());
length->set_exception_state(length->state_before());
length->set_flag(Instruction::DeoptimizeOnException, true);
insert_position = insert_position->insert_after_same_bci(length);
length_instr = length;
}
// Calculate lower bound
Instruction *lower_compare = index_instruction;
if (min_constant) {
ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, min_constant, lower_compare, false, NULL);
insert_position = insert_position->insert_after_same_bci(ao);
lower_compare = ao;
}
// Calculate upper bound
Instruction *upper_compare = index_instruction;
if (max_constant) {
ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, max_constant, upper_compare, false, NULL);
insert_position = insert_position->insert_after_same_bci(ao);
upper_compare = ao;
}
// Trick with unsigned compare is done
int bci = NOT_PRODUCT(first->printable_bci()) PRODUCT_ONLY(-1);
insert_position = predicate(upper_compare, Instruction::aeq, length_instr, state, insert_position, bci);
insert_position = predicate_cmp_with_const(lower_compare, Instruction::leq, -1, state, insert_position);
for (int j = 0; j<info->_list->length(); j++) {
AccessIndexed *ai = info->_list->at(j);
remove_range_check(ai);
}
}
}
if (list_constant.length() > 1) {
AccessIndexed *first = list_constant.at(0);
Instruction *insert_position = first->prev();
ValueStack *state = first->state_before();
// Load max Constant
Constant *constant = new Constant(new IntConstant(max_constant));
NOT_PRODUCT(constant->set_printable_bci(first->printable_bci()));
insert_position = insert_position->insert_after(constant);
Instruction *compare_instr = constant;
Value length_instr = first->length();
if (!length_instr) {
ArrayLength *length = new ArrayLength(array, state->copy());
length->set_exception_state(length->state_before());
length->set_flag(Instruction::DeoptimizeOnException, true);
insert_position = insert_position->insert_after_same_bci(length);
length_instr = length;
}
// Compare for greater or equal to array length
insert_position = predicate(compare_instr, Instruction::geq, length_instr, state, insert_position);
for (int j = 0; j<list_constant.length(); j++) {
AccessIndexed *ai = list_constant.at(j);
remove_range_check(ai);
}
}
}
// Clear data structures for next array
for (int i = 0; i < indices.length(); i++) {
Instruction *index_instruction = indices.at(i);
_access_indexed_info[index_instruction->id()] = NULL;
}
indices.clear();
}
}
bool RangeCheckEliminator::set_process_block_flags(BlockBegin *block) {
Instruction *cur = block;
bool process = false;
while (cur) {
process |= (cur->as_AccessIndexed() != NULL);
cur = cur->next();
}
BlockList *dominates = block->dominates();
for (int i=0; i<dominates->length(); i++) {
BlockBegin *next = dominates->at(i);
process |= set_process_block_flags(next);
}
if (!process) {
block->set(BlockBegin::donot_eliminate_range_checks);
}
return process;
}
bool RangeCheckEliminator::is_ok_for_deoptimization(Instruction *insert_position, Instruction *array_instr, Instruction *length_instr, Instruction *lower_instr, int lower, Instruction *upper_instr, int upper) {
bool upper_check = true;
assert(lower_instr || lower >= 0, "If no lower_instr present, lower must be greater 0");
assert(!lower_instr || lower_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
assert(!upper_instr || upper_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
assert(array_instr, "Array instruction must exist");
assert(array_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
assert(!length_instr || length_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
if (upper_instr && upper_instr->as_ArrayLength() && upper_instr->as_ArrayLength()->array() == array_instr) {
// static check
if (upper >= 0) return false; // would always trigger a deopt:
// array_length + x >= array_length, x >= 0 is always true
upper_check = false;
}
if (lower_instr && lower_instr->as_ArrayLength() && lower_instr->as_ArrayLength()->array() == array_instr) {
if (lower > 0) return false;
}
// No upper check required -> skip
if (upper_check && upper_instr && upper_instr->type()->as_ObjectType() && upper_instr == array_instr) {
// upper_instr is object means that the upper bound is the length
// of the upper_instr.
return false;
}
return true;
}
Instruction* RangeCheckEliminator::insert_after(Instruction* insert_position, Instruction* instr, int bci) {
if (bci != -1) {
NOT_PRODUCT(instr->set_printable_bci(bci));
return insert_position->insert_after(instr);
} else {
return insert_position->insert_after_same_bci(instr);
}
}
Instruction* RangeCheckEliminator::predicate(Instruction* left, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci) {
RangeCheckPredicate *deoptimize = new RangeCheckPredicate(left, cond, true, right, state->copy());
return insert_after(insert_position, deoptimize, bci);
}
Instruction* RangeCheckEliminator::predicate_cmp_with_const(Instruction* instr, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci) {
Constant *const_instr = new Constant(new IntConstant(constant));
insert_position = insert_after(insert_position, const_instr, bci);
return predicate(instr, cond, const_instr, state, insert_position);
}
Instruction* RangeCheckEliminator::predicate_add(Instruction* left, int left_const, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci) {
Constant *constant = new Constant(new IntConstant(left_const));
insert_position = insert_after(insert_position, constant, bci);
ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, constant, left, false, NULL);
insert_position = insert_position->insert_after_same_bci(ao);
return predicate(ao, cond, right, state, insert_position);
}
Instruction* RangeCheckEliminator::predicate_add_cmp_with_const(Instruction* left, int left_const, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci) {
Constant *const_instr = new Constant(new IntConstant(constant));
insert_position = insert_after(insert_position, const_instr, bci);
return predicate_add(left, left_const, cond, const_instr, state, insert_position);
}
// Insert deoptimization
void RangeCheckEliminator::insert_deoptimization(ValueStack *state, Instruction *insert_position, Instruction *array_instr, Instruction *length_instr, Instruction *lower_instr, int lower, Instruction *upper_instr, int upper, AccessIndexed *ai) {
assert(is_ok_for_deoptimization(insert_position, array_instr, length_instr, lower_instr, lower, upper_instr, upper), "should have been tested before");
bool upper_check = !(upper_instr && upper_instr->as_ArrayLength() && upper_instr->as_ArrayLength()->array() == array_instr);
int bci = NOT_PRODUCT(ai->printable_bci()) PRODUCT_ONLY(-1);
if (lower_instr) {
assert(!lower_instr->type()->as_ObjectType(), "Must not be object type");
if (lower == 0) {
// Compare for less than 0
insert_position = predicate_cmp_with_const(lower_instr, Instruction::lss, 0, state, insert_position, bci);
} else if (lower > 0) {
// Compare for smaller 0
insert_position = predicate_add_cmp_with_const(lower_instr, lower, Instruction::lss, 0, state, insert_position, bci);
} else {
assert(lower < 0, "");
// Add 1
lower++;
lower = -lower;
// Compare for smaller or equal 0
insert_position = predicate_cmp_with_const(lower_instr, Instruction::leq, lower, state, insert_position, bci);
}
}
// No upper check required -> skip
if (!upper_check) return;
// We need to know length of array
if (!length_instr) {
// Load length if necessary
ArrayLength *length = new ArrayLength(array_instr, state->copy());
NOT_PRODUCT(length->set_printable_bci(ai->printable_bci()));
length->set_exception_state(length->state_before());
length->set_flag(Instruction::DeoptimizeOnException, true);
insert_position = insert_position->insert_after(length);
length_instr = length;
}
if (!upper_instr) {
// Compare for geq array.length
insert_position = predicate_cmp_with_const(length_instr, Instruction::leq, upper, state, insert_position, bci);
} else {
if (upper_instr->type()->as_ObjectType()) {
assert(state, "must not be null");
assert(upper_instr != array_instr, "should be");
ArrayLength *length = new ArrayLength(upper_instr, state->copy());
NOT_PRODUCT(length->set_printable_bci(ai->printable_bci()));
length->set_flag(Instruction::DeoptimizeOnException, true);
length->set_exception_state(length->state_before());
insert_position = insert_position->insert_after(length);
upper_instr = length;
}
assert(upper_instr->type()->as_IntType(), "Must not be object type!");
if (upper == 0) {
// Compare for geq array.length
insert_position = predicate(upper_instr, Instruction::geq, length_instr, state, insert_position, bci);
} else if (upper < 0) {
// Compare for geq array.length
insert_position = predicate_add(upper_instr, upper, Instruction::geq, length_instr, state, insert_position, bci);
} else {
assert(upper > 0, "");
upper = -upper;
// Compare for geq array.length
insert_position = predicate_add(length_instr, upper, Instruction::leq, upper_instr, state, insert_position, bci);
}
}
}
// Add if condition
void RangeCheckEliminator::add_if_condition(IntegerStack &pushed, Value x, Value y, Instruction::Condition condition) {
if (y->as_Constant()) return;
int const_value = 0;
Value instr_value = x;
Constant *c = x->as_Constant();
ArithmeticOp *ao = x->as_ArithmeticOp();
if (c != NULL) {
const_value = c->type()->as_IntConstant()->value();
instr_value = NULL;
} else if (ao != NULL && (!ao->x()->as_Constant() || !ao->y()->as_Constant()) && ((ao->op() == Bytecodes::_isub && ao->y()->as_Constant()) || ao->op() == Bytecodes::_iadd)) {
assert(!ao->x()->as_Constant() || !ao->y()->as_Constant(), "At least one operator must be non-constant!");
assert(ao->op() == Bytecodes::_isub || ao->op() == Bytecodes::_iadd, "Operation has to be add or sub!");
c = ao->x()->as_Constant();
if (c != NULL) {
const_value = c->type()->as_IntConstant()->value();
instr_value = ao->y();
} else {
c = ao->y()->as_Constant();
if (c != NULL) {
const_value = c->type()->as_IntConstant()->value();
instr_value = ao->x();
}
}
if (ao->op() == Bytecodes::_isub) {
assert(ao->y()->as_Constant(), "1 - x not supported, only x - 1 is valid!");
if (const_value > min_jint) {
const_value = -const_value;
} else {
const_value = 0;
instr_value = x;
}
}
}
update_bound(pushed, y, condition, instr_value, const_value);
}
// Process If
void RangeCheckEliminator::process_if(IntegerStack &pushed, BlockBegin *block, If *cond) {
// Only if we are direct true / false successor and NOT both ! (even this may occur)
if ((cond->tsux() == block || cond->fsux() == block) && cond->tsux() != cond->fsux()) {
Instruction::Condition condition = cond->cond();
if (cond->fsux() == block) {
condition = Instruction::negate(condition);
}
Value x = cond->x();
Value y = cond->y();
if (x->type()->as_IntType() && y->type()->as_IntType()) {
add_if_condition(pushed, y, x, condition);
add_if_condition(pushed, x, y, Instruction::mirror(condition));
}
}
}
// Process access indexed
void RangeCheckEliminator::process_access_indexed(BlockBegin *loop_header, BlockBegin *block, AccessIndexed *ai) {
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2)
);
TRACE_RANGE_CHECK_ELIMINATION(
tty->print_cr("Access indexed: index=%d length=%d", ai->index()->id(), (ai->length() != NULL ? ai->length()->id() :-1 ))
);
if (ai->check_flag(Instruction::NeedsRangeCheckFlag)) {
Bound *index_bound = get_bound(ai->index());
if (!index_bound->has_lower() || !index_bound->has_upper()) {
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Index instruction %d has no lower and/or no upper bound!", ai->index()->id())
);
return;
}
Bound *array_bound;
if (ai->length()) {
array_bound = get_bound(ai->length());
} else {
array_bound = get_bound(ai->array());
}
if (in_array_bound(index_bound, ai->array()) ||
(index_bound && array_bound && index_bound->is_smaller(array_bound) && !index_bound->lower_instr() && index_bound->lower() >= 0)) {
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Bounds check for instruction %d in block B%d can be fully eliminated!", ai->id(), ai->block()->block_id())
);
remove_range_check(ai);
} else if (_optimistic && loop_header) {
assert(ai->array(), "Array must not be null!");
assert(ai->index(), "Index must not be null!");
// Array instruction
Instruction *array_instr = ai->array();
if (!loop_invariant(loop_header, array_instr)) {
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Array %d is not loop invariant to header B%d", ai->array()->id(), loop_header->block_id())
);
return;
}
// Lower instruction
Value index_instr = ai->index();
Value lower_instr = index_bound->lower_instr();
if (!loop_invariant(loop_header, lower_instr)) {
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Lower instruction %d not loop invariant!", lower_instr->id())
);
return;
}
if (!lower_instr && index_bound->lower() < 0) {
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Lower bound smaller than 0 (%d)!", index_bound->lower())
);
return;
}
// Upper instruction
Value upper_instr = index_bound->upper_instr();
if (!loop_invariant(loop_header, upper_instr)) {
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Upper instruction %d not loop invariant!", upper_instr->id())
);
return;
}
// Length instruction
Value length_instr = ai->length();
if (!loop_invariant(loop_header, length_instr)) {
// Generate length instruction yourself!
length_instr = NULL;
}
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("LOOP INVARIANT access indexed %d found in block B%d!", ai->id(), ai->block()->block_id())
);
BlockBegin *pred_block = loop_header->dominator();
assert(pred_block != NULL, "Every loop header has a dominator!");
BlockEnd *pred_block_end = pred_block->end();
Instruction *insert_position = pred_block_end->prev();
ValueStack *state = pred_block_end->state_before();
if (pred_block_end->as_Goto() && state == NULL) state = pred_block_end->state();
assert(state, "State must not be null");
// Add deoptimization to dominator of loop header
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Inserting deopt at bci %d in block B%d!", state->bci(), insert_position->block()->block_id())
);
if (!is_ok_for_deoptimization(insert_position, array_instr, length_instr, lower_instr, index_bound->lower(), upper_instr, index_bound->upper())) {
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Could not eliminate because of static analysis!")
);
return;
}
insert_deoptimization(state, insert_position, array_instr, length_instr, lower_instr, index_bound->lower(), upper_instr, index_bound->upper(), ai);
// Finally remove the range check!
remove_range_check(ai);
}
}
}
void RangeCheckEliminator::remove_range_check(AccessIndexed *ai) {
ai->set_flag(Instruction::NeedsRangeCheckFlag, false);
// no range check, no need for the length instruction anymore
ai->clear_length();
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(ai->dominator_depth()*2);
tty->print_cr("Range check for instruction %d eliminated!", ai->id());
);
ASSERT_RANGE_CHECK_ELIMINATION(
Value array_length = ai->length();
if (!array_length) {
array_length = ai->array();
assert(array_length->type()->as_ObjectType(), "Has to be object type!");
}
int cur_constant = -1;
Value cur_value = array_length;
if (cur_value->type()->as_IntConstant()) {
cur_constant += cur_value->type()->as_IntConstant()->value();
cur_value = NULL;
}
Bound *new_index_bound = new Bound(0, NULL, cur_constant, cur_value);
add_assertions(new_index_bound, ai->index(), ai);
);
}
// Calculate bounds for instruction in this block and children blocks in the dominator tree
void RangeCheckEliminator::calc_bounds(BlockBegin *block, BlockBegin *loop_header) {
// Ensures a valid loop_header
assert(!loop_header || loop_header->is_set(BlockBegin::linear_scan_loop_header_flag), "Loop header has to be real !");
// Tracing output
TRACE_RANGE_CHECK_ELIMINATION(
tty->fill_to(block->dominator_depth()*2);
tty->print_cr("Block B%d", block->block_id());
);
// Pushed stack for conditions
IntegerStack pushed;
// Process If
BlockBegin *parent = block->dominator();
if (parent != NULL) {
If *cond = parent->end()->as_If();
if (cond != NULL) {
process_if(pushed, block, cond);
}
}
// Interate over current block
InstructionList arrays;
AccessIndexedList accessIndexed;
Instruction *cur = block;
while (cur) {
// Ensure cur wasn't inserted during the elimination
if (cur->id() < this->_bounds.length()) {
// Process only if it is an access indexed instruction
AccessIndexed *ai = cur->as_AccessIndexed();
if (ai != NULL) {
process_access_indexed(loop_header, block, ai);
accessIndexed.append(ai);
if (!arrays.contains(ai->array())) {
arrays.append(ai->array());
}
Bound *b = get_bound(ai->index());
if (!b->lower_instr()) {
// Lower bound is constant
update_bound(pushed, ai->index(), Instruction::geq, NULL, 0);
}
if (!b->has_upper()) {
if (ai->length() && ai->length()->type()->as_IntConstant()) {
int value = ai->length()->type()->as_IntConstant()->value();
update_bound(pushed, ai->index(), Instruction::lss, NULL, value);
} else {
// Has no upper bound
Instruction *instr = ai->length();
if (instr != NULL) instr = ai->array();
update_bound(pushed, ai->index(), Instruction::lss, instr, 0);
}
}
}
}
cur = cur->next();
}
// Output current condition stack
TRACE_RANGE_CHECK_ELIMINATION(dump_condition_stack(block));
// Do in block motion of range checks
in_block_motion(block, accessIndexed, arrays);
// Call all dominated blocks
for (int i=0; i<block->dominates()->length(); i++) {
BlockBegin *next = block->dominates()->at(i);
if (!next->is_set(BlockBegin::donot_eliminate_range_checks)) {
// if current block is a loop header and:
// - next block belongs to the same loop
// or
// - next block belongs to an inner loop
// then current block is the loop header for next block
if (block->is_set(BlockBegin::linear_scan_loop_header_flag) && (block->loop_index() == next->loop_index() || next->loop_depth() > block->loop_depth())) {
calc_bounds(next, block);
} else {
calc_bounds(next, loop_header);
}
}
}
// Reset stack
for (int i=0; i<pushed.length(); i++) {
_bounds[pushed[i]]->pop();
}
}
#ifndef PRODUCT
// Dump condition stack
void RangeCheckEliminator::dump_condition_stack(BlockBegin *block) {
for (int i=0; i<_ir->linear_scan_order()->length(); i++) {
BlockBegin *cur_block = _ir->linear_scan_order()->at(i);
Instruction *instr = cur_block;
for_each_phi_fun(cur_block, phi,
BoundStack *bound_stack = _bounds.at(phi->id());
if (bound_stack && bound_stack->length() > 0) {
Bound *bound = bound_stack->top();
if ((bound->has_lower() || bound->has_upper()) && (bound->lower_instr() != phi || bound->upper_instr() != phi || bound->lower() != 0 || bound->upper() != 0)) {
TRACE_RANGE_CHECK_ELIMINATION(tty->fill_to(2*block->dominator_depth());
tty->print("i%d", phi->id());
tty->print(": ");
bound->print();
tty->cr();
);
}
});
while (!instr->as_BlockEnd()) {
if (instr->id() < _bounds.length()) {
BoundStack *bound_stack = _bounds.at(instr->id());
if (bound_stack && bound_stack->length() > 0) {
Bound *bound = bound_stack->top();
if ((bound->has_lower() || bound->has_upper()) && (bound->lower_instr() != instr || bound->upper_instr() != instr || bound->lower() != 0 || bound->upper() != 0)) {
TRACE_RANGE_CHECK_ELIMINATION(tty->fill_to(2*block->dominator_depth());
tty->print("i%d", instr->id());
tty->print(": ");
bound->print();
tty->cr();
);
}
}
}
instr = instr->next();
}
}
}
#endif
// Verification or the IR
RangeCheckEliminator::Verification::Verification(IR *ir) : _used(BlockBegin::number_of_blocks(), false) {
this->_ir = ir;
ir->iterate_linear_scan_order(this);
}
// Verify this block
void RangeCheckEliminator::Verification::block_do(BlockBegin *block) {
If *cond = block->end()->as_If();
// Watch out: tsux and fsux can be the same!
if (block->number_of_sux() > 1) {
for (int i=0; i<block->number_of_sux(); i++) {
BlockBegin *sux = block->sux_at(i);
BlockBegin *pred = NULL;
for (int j=0; j<sux->number_of_preds(); j++) {
BlockBegin *cur = sux->pred_at(j);
assert(cur != NULL, "Predecessor must not be null");
if (!pred) {
pred = cur;
}
assert(cur == pred, "Block must not have more than one predecessor if its predecessor has more than one successor");
}
assert(sux->number_of_preds() >= 1, "Block must have at least one predecessor");
assert(sux->pred_at(0) == block, "Wrong successor");
}
}
BlockBegin *dominator = block->dominator();
if (dominator) {
assert(block != _ir->start(), "Start block must not have a dominator!");
assert(can_reach(dominator, block), "Dominator can't reach his block !");
assert(can_reach(_ir->start(), dominator), "Dominator is unreachable !");
assert(!can_reach(_ir->start(), block, dominator), "Wrong dominator ! Block can be reached anyway !");
BlockList *all_blocks = _ir->linear_scan_order();
for (int i=0; i<all_blocks->length(); i++) {
BlockBegin *cur = all_blocks->at(i);
if (cur != dominator && cur != block) {
assert(can_reach(dominator, block, cur), "There has to be another dominator!");
}
}
} else {
assert(block == _ir->start(), "Only start block must not have a dominator");
}
if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
int loop_index = block->loop_index();
BlockList *all_blocks = _ir->linear_scan_order();
assert(block->number_of_preds() >= 1, "Block must have at least one predecessor");
assert(!block->is_set(BlockBegin::exception_entry_flag), "Loop header must not be exception handler!");
// Sometimes, the backbranch comes from an exception handler. In
// this case, loop indexes/loop depths may not appear correct.
bool loop_through_xhandler = false;
for (int i = 0; i < block->number_of_exception_handlers(); i++) {
BlockBegin *xhandler = block->exception_handler_at(i);
for (int j = 0; j < block->number_of_preds(); j++) {
if (dominates(xhandler, block->pred_at(j)) || xhandler == block->pred_at(j)) {
loop_through_xhandler = true;
}
}
}
for (int i=0; i<block->number_of_sux(); i++) {
BlockBegin *sux = block->sux_at(i);
assert(sux->loop_depth() != block->loop_depth() || sux->loop_index() == block->loop_index() || loop_through_xhandler, "Loop index has to be same");
assert(sux->loop_depth() == block->loop_depth() || sux->loop_index() != block->loop_index(), "Loop index has to be different");
}
for (int i=0; i<all_blocks->length(); i++) {
BlockBegin *cur = all_blocks->at(i);
if (cur->loop_index() == loop_index && cur != block) {
assert(dominates(block->dominator(), cur), "Dominator of loop header must dominate all loop blocks");
}
}
}
Instruction *cur = block;
while (cur) {
assert(cur->block() == block, "Block begin has to be set correctly!");
cur = cur->next();
}
}
// Loop header must dominate all loop blocks
bool RangeCheckEliminator::Verification::dominates(BlockBegin *dominator, BlockBegin *block) {
BlockBegin *cur = block->dominator();
while (cur && cur != dominator) {
cur = cur->dominator();
}
return cur == dominator;
}
// Try to reach Block end beginning in Block start and not using Block dont_use
bool RangeCheckEliminator::Verification::can_reach(BlockBegin *start, BlockBegin *end, BlockBegin *dont_use /* = NULL */) {
if (start == end) return start != dont_use;
// Simple BSF from start to end
// BlockBeginList _current;
for (int i=0; i<_used.length(); i++) {
_used[i] = false;
}
_current.truncate(0);
_successors.truncate(0);
if (start != dont_use) {
_current.push(start);
_used[start->block_id()] = true;
}
// BlockBeginList _successors;
while (_current.length() > 0) {
BlockBegin *cur = _current.pop();
// Add exception handlers to list
for (int i=0; i<cur->number_of_exception_handlers(); i++) {
BlockBegin *xhandler = cur->exception_handler_at(i);
_successors.push(xhandler);
// Add exception handlers of _successors to list
for (int j=0; j<xhandler->number_of_exception_handlers(); j++) {
BlockBegin *sux_xhandler = xhandler->exception_handler_at(j);
_successors.push(sux_xhandler);
}
}
// Add normal _successors to list
for (int i=0; i<cur->number_of_sux(); i++) {
BlockBegin *sux = cur->sux_at(i);
_successors.push(sux);
// Add exception handlers of _successors to list
for (int j=0; j<sux->number_of_exception_handlers(); j++) {
BlockBegin *xhandler = sux->exception_handler_at(j);
_successors.push(xhandler);
}
}
for (int i=0; i<_successors.length(); i++) {
BlockBegin *sux = _successors[i];
assert(sux != NULL, "Successor must not be NULL!");
if (sux == end) {
return true;
}
if (sux != dont_use && !_used[sux->block_id()]) {
_used[sux->block_id()] = true;
_current.push(sux);
}
}
_successors.truncate(0);
}
return false;
}
// Bound
RangeCheckEliminator::Bound::~Bound() {
}
// Bound constructor
RangeCheckEliminator::Bound::Bound() {
init();
this->_lower = min_jint;
this->_upper = max_jint;
this->_lower_instr = NULL;
this->_upper_instr = NULL;
}
// Bound constructor
RangeCheckEliminator::Bound::Bound(int lower, Value lower_instr, int upper, Value upper_instr) {
init();
assert(!lower_instr || !lower_instr->as_Constant() || !lower_instr->type()->as_IntConstant(), "Must not be constant!");
assert(!upper_instr || !upper_instr->as_Constant() || !upper_instr->type()->as_IntConstant(), "Must not be constant!");
this->_lower = lower;
this->_upper = upper;
this->_lower_instr = lower_instr;
this->_upper_instr = upper_instr;
}
// Bound constructor
RangeCheckEliminator::Bound::Bound(Instruction::Condition cond, Value v, int constant) {
assert(!v || (v->type() && (v->type()->as_IntType() || v->type()->as_ObjectType())), "Type must be array or integer!");
assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
init();
if (cond == Instruction::eql) {
_lower = constant;
_lower_instr = v;
_upper = constant;
_upper_instr = v;
} else if (cond == Instruction::neq) {
_lower = min_jint;
_upper = max_jint;
_lower_instr = NULL;
_upper_instr = NULL;
if (v == NULL) {
if (constant == min_jint) {
_lower++;
}
if (constant == max_jint) {
_upper--;
}
}
} else if (cond == Instruction::geq) {
_lower = constant;
_lower_instr = v;
_upper = max_jint;
_upper_instr = NULL;
} else if (cond == Instruction::leq) {
_lower = min_jint;
_lower_instr = NULL;
_upper = constant;
_upper_instr = v;
} else {
ShouldNotReachHere();
}
}
// Set lower
void RangeCheckEliminator::Bound::set_lower(int value, Value v) {
assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
this->_lower = value;
this->_lower_instr = v;
}
// Set upper
void RangeCheckEliminator::Bound::set_upper(int value, Value v) {
assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
this->_upper = value;
this->_upper_instr = v;
}
// Add constant -> no overflow may occur
void RangeCheckEliminator::Bound::add_constant(int value) {
this->_lower += value;
this->_upper += value;
}
// Init
void RangeCheckEliminator::Bound::init() {
}
// or
void RangeCheckEliminator::Bound::or_op(Bound *b) {
// Watch out, bound is not guaranteed not to overflow!
// Update lower bound
if (_lower_instr != b->_lower_instr || (_lower_instr && _lower != b->_lower)) {
_lower_instr = NULL;
_lower = min_jint;
} else {
_lower = MIN2(_lower, b->_lower);
}
// Update upper bound
if (_upper_instr != b->_upper_instr || (_upper_instr && _upper != b->_upper)) {
_upper_instr = NULL;
_upper = max_jint;
} else {
_upper = MAX2(_upper, b->_upper);
}
}
// and
void RangeCheckEliminator::Bound::and_op(Bound *b) {
// Update lower bound
if (_lower_instr == b->_lower_instr) {
_lower = MAX2(_lower, b->_lower);
}
if (b->has_lower()) {
bool set = true;
if (_lower_instr != NULL && b->_lower_instr != NULL) {
set = (_lower_instr->dominator_depth() > b->_lower_instr->dominator_depth());
}
if (set) {
_lower = b->_lower;
_lower_instr = b->_lower_instr;
}
}
// Update upper bound
if (_upper_instr == b->_upper_instr) {
_upper = MIN2(_upper, b->_upper);
}
if (b->has_upper()) {
bool set = true;
if (_upper_instr != NULL && b->_upper_instr != NULL) {
set = (_upper_instr->dominator_depth() > b->_upper_instr->dominator_depth());
}
if (set) {
_upper = b->_upper;
_upper_instr = b->_upper_instr;
}
}
}
// has_upper
bool RangeCheckEliminator::Bound::has_upper() {
return _upper_instr != NULL || _upper < max_jint;
}
// is_smaller
bool RangeCheckEliminator::Bound::is_smaller(Bound *b) {
if (b->_lower_instr != _upper_instr) {
return false;
}
return _upper < b->_lower;
}
// has_lower
bool RangeCheckEliminator::Bound::has_lower() {
return _lower_instr != NULL || _lower > min_jint;
}
// in_array_bound
bool RangeCheckEliminator::in_array_bound(Bound *bound, Value array){
if (!bound) return false;
assert(array != NULL, "Must not be null!");
assert(bound != NULL, "Must not be null!");
if (bound->lower() >=0 && bound->lower_instr() == NULL && bound->upper() < 0 && bound->upper_instr() != NULL) {
ArrayLength *len = bound->upper_instr()->as_ArrayLength();
if (bound->upper_instr() == array || (len != NULL && len->array() == array)) {
return true;
}
}
return false;
}
// remove_lower
void RangeCheckEliminator::Bound::remove_lower() {
_lower = min_jint;
_lower_instr = NULL;
}
// remove_upper
void RangeCheckEliminator::Bound::remove_upper() {
_upper = max_jint;
_upper_instr = NULL;
}
// upper
int RangeCheckEliminator::Bound::upper() {
return _upper;
}
// lower
int RangeCheckEliminator::Bound::lower() {
return _lower;
}
// upper_instr
Value RangeCheckEliminator::Bound::upper_instr() {
return _upper_instr;
}
// lower_instr
Value RangeCheckEliminator::Bound::lower_instr() {
return _lower_instr;
}
// print
void RangeCheckEliminator::Bound::print() {
tty->print("%s", "");
if (this->_lower_instr || this->_lower != min_jint) {
if (this->_lower_instr) {
tty->print("i%d", this->_lower_instr->id());
if (this->_lower > 0) {
tty->print("+%d", _lower);
}
if (this->_lower < 0) {
tty->print("%d", _lower);
}
} else {
tty->print("%d", _lower);
}
tty->print(" <= ");
}
tty->print("x");
if (this->_upper_instr || this->_upper != max_jint) {
tty->print(" <= ");
if (this->_upper_instr) {
tty->print("i%d", this->_upper_instr->id());
if (this->_upper > 0) {
tty->print("+%d", _upper);
}
if (this->_upper < 0) {
tty->print("%d", _upper);
}
} else {
tty->print("%d", _upper);
}
}
}
// Copy
RangeCheckEliminator::Bound *RangeCheckEliminator::Bound::copy() {
Bound *b = new Bound();
b->_lower = _lower;
b->_lower_instr = _lower_instr;
b->_upper = _upper;
b->_upper_instr = _upper_instr;
return b;
}
#ifdef ASSERT
// Add assertion
void RangeCheckEliminator::Bound::add_assertion(Instruction *instruction, Instruction *position, int i, Value instr, Instruction::Condition cond) {
Instruction *result = position;
Instruction *compare_with = NULL;
ValueStack *state = position->state_before();
if (position->as_BlockEnd() && !position->as_Goto()) {
state = position->as_BlockEnd()->state_before();
}
Instruction *instruction_before = position->prev();
if (position->as_Return() && Compilation::current()->method()->is_synchronized() && instruction_before->as_MonitorExit()) {
instruction_before = instruction_before->prev();
}
result = instruction_before;
// Load constant only if needed
Constant *constant = NULL;
if (i != 0 || !instr) {
constant = new Constant(new IntConstant(i));
NOT_PRODUCT(constant->set_printable_bci(position->printable_bci()));
result = result->insert_after(constant);
compare_with = constant;
}
if (instr) {
assert(instr->type()->as_ObjectType() || instr->type()->as_IntType(), "Type must be array or integer!");
compare_with = instr;
// Load array length if necessary
Instruction *op = instr;
if (instr->type()->as_ObjectType()) {
assert(state, "must not be null");
ArrayLength *length = new ArrayLength(instr, state->copy());
NOT_PRODUCT(length->set_printable_bci(position->printable_bci()));
length->set_exception_state(length->state_before());
result = result->insert_after(length);
op = length;
compare_with = length;
}
// Add operation only if necessary
if (constant) {
ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, constant, op, false, NULL);
NOT_PRODUCT(ao->set_printable_bci(position->printable_bci()));
result = result->insert_after(ao);
compare_with = ao;
// TODO: Check that add operation does not overflow!
}
}
assert(compare_with != NULL, "You have to compare with something!");
assert(instruction != NULL, "Instruction must not be null!");
if (instruction->type()->as_ObjectType()) {
// Load array length if necessary
Instruction *op = instruction;
assert(state, "must not be null");
ArrayLength *length = new ArrayLength(instruction, state->copy());
length->set_exception_state(length->state_before());
NOT_PRODUCT(length->set_printable_bci(position->printable_bci()));
result = result->insert_after(length);
instruction = length;
}
Assert *assert = new Assert(instruction, cond, false, compare_with);
NOT_PRODUCT(assert->set_printable_bci(position->printable_bci()));
result->insert_after(assert);
}
// Add assertions
void RangeCheckEliminator::add_assertions(Bound *bound, Instruction *instruction, Instruction *position) {
// Add lower bound assertion
if (bound->has_lower()) {
bound->add_assertion(instruction, position, bound->lower(), bound->lower_instr(), Instruction::geq);
}
// Add upper bound assertion
if (bound->has_upper()) {
bound->add_assertion(instruction, position, bound->upper(), bound->upper_instr(), Instruction::leq);
}
}
#endif
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