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7153771: array bound check elimination for c1

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When possible optimize out array bound checks, inserting predicates when needed.

Reviewed-by: never, kvn, twisti
This commit is contained in:
Thomas Wuerthinger 2013-03-21 09:27:54 +01:00 • committed by Roland Westrelin
parent 2f4ecb86a2
commit 06ef4cddf7
40 changed files with 2861 additions and 153 deletions
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137
hotspot/src/share/vm/c1/c1_LIRGenerator.cpp
View file

@ -403,6 +403,10 @@ void LIRGenerator::walk(Value instr) {
CodeEmitInfo* LIRGenerator::state_for(Instruction* x, ValueStack* state, bool ignore_xhandler) {
assert(state != NULL, "state must be defined");
#ifndef PRODUCT
state->verify();
#endif
ValueStack* s = state;
for_each_state(s) {
if (s->kind() == ValueStack::EmptyExceptionState) {
@ -453,7 +457,7 @@ CodeEmitInfo* LIRGenerator::state_for(Instruction* x, ValueStack* state, bool ig
}
}
return new CodeEmitInfo(state, ignore_xhandler ? NULL : x->exception_handlers());
return new CodeEmitInfo(state, ignore_xhandler ? NULL : x->exception_handlers(), x->check_flag(Instruction::DeoptimizeOnException));
}
@ -1792,11 +1796,18 @@ void LIRGenerator::do_LoadField(LoadField* x) {
}
#endif
bool stress_deopt = StressLoopInvariantCodeMotion && info && info->deoptimize_on_exception();
if (x->needs_null_check() &&
(needs_patching ||
MacroAssembler::needs_explicit_null_check(x->offset()))) {
MacroAssembler::needs_explicit_null_check(x->offset()) ||
stress_deopt)) {
LIR_Opr obj = object.result();
if (stress_deopt) {
obj = new_register(T_OBJECT);
__ move(LIR_OprFact::oopConst(NULL), obj);
}
// emit an explicit null check because the offset is too large
__ null_check(object.result(), new CodeEmitInfo(info));
__ null_check(obj, new CodeEmitInfo(info));
}
LIR_Opr reg = rlock_result(x, field_type);
@ -1861,6 +1872,8 @@ void LIRGenerator::do_NIOCheckIndex(Intrinsic* x) {
void LIRGenerator::do_ArrayLength(ArrayLength* x) {
if (x->use_count() == 0 && !x->can_trap()) return;
LIRItem array(x->array(), this);
array.load_item();
LIR_Opr reg = rlock_result(x);
@ -1873,6 +1886,11 @@ void LIRGenerator::do_ArrayLength(ArrayLength* x) {
} else {
info = state_for(nc);
}
if (StressLoopInvariantCodeMotion && info->deoptimize_on_exception()) {
LIR_Opr obj = new_register(T_OBJECT);
__ move(LIR_OprFact::oopConst(NULL), obj);
__ null_check(obj, new CodeEmitInfo(info));
}
}
__ load(new LIR_Address(array.result(), arrayOopDesc::length_offset_in_bytes(), T_INT), reg, info, lir_patch_none);
}
@ -1883,14 +1901,11 @@ void LIRGenerator::do_LoadIndexed(LoadIndexed* x) {
LIRItem array(x->array(), this);
LIRItem index(x->index(), this);
LIRItem length(this);
bool needs_range_check = true;
bool needs_range_check = x->compute_needs_range_check();
if (use_length) {
needs_range_check = x->compute_needs_range_check();
if (needs_range_check) {
length.set_instruction(x->length());
length.load_item();
}
if (use_length && needs_range_check) {
length.set_instruction(x->length());
length.load_item();
}
array.load_item();
@ -1910,13 +1925,20 @@ void LIRGenerator::do_LoadIndexed(LoadIndexed* x) {
} else {
null_check_info = range_check_info;
}
if (StressLoopInvariantCodeMotion && null_check_info->deoptimize_on_exception()) {
LIR_Opr obj = new_register(T_OBJECT);
__ move(LIR_OprFact::oopConst(NULL), obj);
__ null_check(obj, new CodeEmitInfo(null_check_info));
}
}
// emit array address setup early so it schedules better
LIR_Address* array_addr = emit_array_address(array.result(), index.result(), x->elt_type(), false);
if (GenerateRangeChecks && needs_range_check) {
if (use_length) {
if (StressLoopInvariantCodeMotion && range_check_info->deoptimize_on_exception()) {
__ branch(lir_cond_always, T_ILLEGAL, new RangeCheckStub(range_check_info, index.result()));
} else if (use_length) {
// TODO: use a (modified) version of array_range_check that does not require a
// constant length to be loaded to a register
__ cmp(lir_cond_belowEqual, length.result(), index.result());
@ -2634,7 +2656,7 @@ void LIRGenerator::do_Base(Base* x) {
LIR_Opr lock = new_register(T_INT);
__ load_stack_address_monitor(0, lock);
CodeEmitInfo* info = new CodeEmitInfo(scope()->start()->state()->copy(ValueStack::StateBefore, SynchronizationEntryBCI), NULL);
CodeEmitInfo* info = new CodeEmitInfo(scope()->start()->state()->copy(ValueStack::StateBefore, SynchronizationEntryBCI), NULL, x->check_flag(Instruction::DeoptimizeOnException));
CodeStub* slow_path = new MonitorEnterStub(obj, lock, info);
// receiver is guaranteed non-NULL so don't need CodeEmitInfo
@ -2644,7 +2666,7 @@ void LIRGenerator::do_Base(Base* x) {
// increment invocation counters if needed
if (!method()->is_accessor()) { // Accessors do not have MDOs, so no counting.
CodeEmitInfo* info = new CodeEmitInfo(scope()->start()->state()->copy(ValueStack::StateBefore, SynchronizationEntryBCI), NULL);
CodeEmitInfo* info = new CodeEmitInfo(scope()->start()->state()->copy(ValueStack::StateBefore, SynchronizationEntryBCI), NULL, false);
increment_invocation_counter(info);
}
@ -3102,6 +3124,95 @@ void LIRGenerator::do_RuntimeCall(RuntimeCall* x) {
}
}
void LIRGenerator::do_Assert(Assert *x) {
#ifdef ASSERT
ValueTag tag = x->x()->type()->tag();
If::Condition cond = x->cond();
LIRItem xitem(x->x(), this);
LIRItem yitem(x->y(), this);
LIRItem* xin = &xitem;
LIRItem* yin = &yitem;
assert(tag == intTag, "Only integer assertions are valid!");
xin->load_item();
yin->dont_load_item();
set_no_result(x);
LIR_Opr left = xin->result();
LIR_Opr right = yin->result();
__ lir_assert(lir_cond(x->cond()), left, right, x->message(), true);
#endif
}
void LIRGenerator::do_RangeCheckPredicate(RangeCheckPredicate *x) {
Instruction *a = x->x();
Instruction *b = x->y();
if (!a || StressRangeCheckElimination) {
assert(!b || StressRangeCheckElimination, "B must also be null");
CodeEmitInfo *info = state_for(x, x->state());
CodeStub* stub = new PredicateFailedStub(info);
__ jump(stub);
} else if (a->type()->as_IntConstant() && b->type()->as_IntConstant()) {
int a_int = a->type()->as_IntConstant()->value();
int b_int = b->type()->as_IntConstant()->value();
bool ok = false;
switch(x->cond()) {
case Instruction::eql: ok = (a_int == b_int); break;
case Instruction::neq: ok = (a_int != b_int); break;
case Instruction::lss: ok = (a_int < b_int); break;
case Instruction::leq: ok = (a_int <= b_int); break;
case Instruction::gtr: ok = (a_int > b_int); break;
case Instruction::geq: ok = (a_int >= b_int); break;
case Instruction::aeq: ok = ((unsigned int)a_int >= (unsigned int)b_int); break;
case Instruction::beq: ok = ((unsigned int)a_int <= (unsigned int)b_int); break;
default: ShouldNotReachHere();
}
if (ok) {
CodeEmitInfo *info = state_for(x, x->state());
CodeStub* stub = new PredicateFailedStub(info);
__ jump(stub);
}
} else {
ValueTag tag = x->x()->type()->tag();
If::Condition cond = x->cond();
LIRItem xitem(x->x(), this);
LIRItem yitem(x->y(), this);
LIRItem* xin = &xitem;
LIRItem* yin = &yitem;
assert(tag == intTag, "Only integer deoptimizations are valid!");
xin->load_item();
yin->dont_load_item();
set_no_result(x);
LIR_Opr left = xin->result();
LIR_Opr right = yin->result();
CodeEmitInfo *info = state_for(x, x->state());
CodeStub* stub = new PredicateFailedStub(info);
__ cmp(lir_cond(cond), left, right);
__ branch(lir_cond(cond), right->type(), stub);
}
}
LIR_Opr LIRGenerator::call_runtime(Value arg1, address entry, ValueType* result_type, CodeEmitInfo* info) {
LIRItemList args(1);
LIRItem value(arg1, this);