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/*
* Copyright (c) 1998, 2022, 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/ciMethodData.hpp"
#include "classfile/vmSymbols.hpp"
#include "compiler/compileLog.hpp"
#include "interpreter/linkResolver.hpp"
#include "jvm_io.h"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "oops/oop.inline.hpp"
#include "opto/addnode.hpp"
#include "opto/castnode.hpp"
#include "opto/convertnode.hpp"
#include "opto/divnode.hpp"
#include "opto/idealGraphPrinter.hpp"
#include "opto/matcher.hpp"
#include "opto/memnode.hpp"
#include "opto/mulnode.hpp"
#include "opto/opaquenode.hpp"
#include "opto/parse.hpp"
#include "opto/runtime.hpp"
#include "runtime/deoptimization.hpp"
#include "runtime/sharedRuntime.hpp"
#ifndef PRODUCT
extern int explicit_null_checks_inserted,
explicit_null_checks_elided;
#endif
//---------------------------------array_load----------------------------------
void Parse::array_load(BasicType bt) {
const Type* elemtype = Type::TOP;
bool big_val = bt == T_DOUBLE || bt == T_LONG;
Node* adr = array_addressing(bt, 0, elemtype);
if (stopped()) return; // guaranteed null or range check
pop(); // index (already used)
Node* array = pop(); // the array itself
if (elemtype == TypeInt::BOOL) {
bt = T_BOOLEAN;
}
const TypeAryPtr* adr_type = TypeAryPtr::get_array_body_type(bt);
Node* ld = access_load_at(array, adr, adr_type, elemtype, bt,
IN_HEAP | IS_ARRAY | C2_CONTROL_DEPENDENT_LOAD);
if (big_val) {
push_pair(ld);
} else {
push(ld);
}
}
//--------------------------------array_store----------------------------------
void Parse::array_store(BasicType bt) {
const Type* elemtype = Type::TOP;
bool big_val = bt == T_DOUBLE || bt == T_LONG;
Node* adr = array_addressing(bt, big_val ? 2 : 1, elemtype);
if (stopped()) return; // guaranteed null or range check
if (bt == T_OBJECT) {
array_store_check();
if (stopped()) {
return;
}
}
Node* val; // Oop to store
if (big_val) {
val = pop_pair();
} else {
val = pop();
}
pop(); // index (already used)
Node* array = pop(); // the array itself
if (elemtype == TypeInt::BOOL) {
bt = T_BOOLEAN;
}
const TypeAryPtr* adr_type = TypeAryPtr::get_array_body_type(bt);
access_store_at(array, adr, adr_type, val, elemtype, bt, MO_UNORDERED | IN_HEAP | IS_ARRAY);
}
//------------------------------array_addressing-------------------------------
// Pull array and index from the stack. Compute pointer-to-element.
Node* Parse::array_addressing(BasicType type, int vals, const Type*& elemtype) {
Node *idx = peek(0+vals); // Get from stack without popping
Node *ary = peek(1+vals); // in case of exception
// Null check the array base, with correct stack contents
ary = null_check(ary, T_ARRAY);
// Compile-time detect of null-exception?
if (stopped()) return top();
const TypeAryPtr* arytype = _gvn.type(ary)->is_aryptr();
const TypeInt* sizetype = arytype->size();
elemtype = arytype->elem();
if (UseUniqueSubclasses) {
const Type* el = elemtype->make_ptr();
if (el && el->isa_instptr()) {
const TypeInstPtr* toop = el->is_instptr();
if (toop->instance_klass()->unique_concrete_subklass()) {
// If we load from "AbstractClass[]" we must see "ConcreteSubClass".
const Type* subklass = Type::get_const_type(toop->instance_klass());
elemtype = subklass->join_speculative(el);
}
}
}
// Check for big class initializers with all constant offsets
// feeding into a known-size array.
const TypeInt* idxtype = _gvn.type(idx)->is_int();
// See if the highest idx value is less than the lowest array bound,
// and if the idx value cannot be negative:
bool need_range_check = true;
if (idxtype->_hi < sizetype->_lo && idxtype->_lo >= 0) {
need_range_check = false;
if (C->log() != NULL) C->log()->elem("observe that='!need_range_check'");
}
if (!arytype->is_loaded()) {
// Only fails for some -Xcomp runs
// The class is unloaded. We have to run this bytecode in the interpreter.
ciKlass* klass = arytype->unloaded_klass();
uncommon_trap(Deoptimization::Reason_unloaded,
Deoptimization::Action_reinterpret,
klass, "!loaded array");
return top();
}
// Do the range check
if (GenerateRangeChecks && need_range_check) {
Node* tst;
if (sizetype->_hi <= 0) {
// The greatest array bound is negative, so we can conclude that we're
// compiling unreachable code, but the unsigned compare trick used below
// only works with non-negative lengths. Instead, hack "tst" to be zero so
// the uncommon_trap path will always be taken.
tst = _gvn.intcon(0);
} else {
// Range is constant in array-oop, so we can use the original state of mem
Node* len = load_array_length(ary);
// Test length vs index (standard trick using unsigned compare)
Node* chk = _gvn.transform( new CmpUNode(idx, len) );
BoolTest::mask btest = BoolTest::lt;
tst = _gvn.transform( new BoolNode(chk, btest) );
}
RangeCheckNode* rc = new RangeCheckNode(control(), tst, PROB_MAX, COUNT_UNKNOWN);
_gvn.set_type(rc, rc->Value(&_gvn));
if (!tst->is_Con()) {
record_for_igvn(rc);
}
set_control(_gvn.transform(new IfTrueNode(rc)));
// Branch to failure if out of bounds
{
PreserveJVMState pjvms(this);
set_control(_gvn.transform(new IfFalseNode(rc)));
if (C->allow_range_check_smearing()) {
// Do not use builtin_throw, since range checks are sometimes
// made more stringent by an optimistic transformation.
// This creates "tentative" range checks at this point,
// which are not guaranteed to throw exceptions.
// See IfNode::Ideal, is_range_check, adjust_check.
uncommon_trap(Deoptimization::Reason_range_check,
Deoptimization::Action_make_not_entrant,
NULL, "range_check");
} else {
// If we have already recompiled with the range-check-widening
// heroic optimization turned off, then we must really be throwing
// range check exceptions.
builtin_throw(Deoptimization::Reason_range_check);
}
}
}
// Check for always knowing you are throwing a range-check exception
if (stopped()) return top();
// Make array address computation control dependent to prevent it
// from floating above the range check during loop optimizations.
Node* ptr = array_element_address(ary, idx, type, sizetype, control());
assert(ptr != top(), "top should go hand-in-hand with stopped");
return ptr;
}
// returns IfNode
IfNode* Parse::jump_if_fork_int(Node* a, Node* b, BoolTest::mask mask, float prob, float cnt) {
Node *cmp = _gvn.transform(new CmpINode(a, b)); // two cases: shiftcount > 32 and shiftcount <= 32
Node *tst = _gvn.transform(new BoolNode(cmp, mask));
IfNode *iff = create_and_map_if(control(), tst, prob, cnt);
return iff;
}
// sentinel value for the target bci to mark never taken branches
// (according to profiling)
static const int never_reached = INT_MAX;
//------------------------------helper for tableswitch-------------------------
void Parse::jump_if_true_fork(IfNode *iff, int dest_bci_if_true, bool unc) {
// True branch, use existing map info
{ PreserveJVMState pjvms(this);
Node *iftrue = _gvn.transform( new IfTrueNode (iff) );
set_control( iftrue );
if (unc) {
repush_if_args();
uncommon_trap(Deoptimization::Reason_unstable_if,
Deoptimization::Action_reinterpret,
NULL,
"taken always");
} else {
assert(dest_bci_if_true != never_reached, "inconsistent dest");
merge_new_path(dest_bci_if_true);
}
}
// False branch
Node *iffalse = _gvn.transform( new IfFalseNode(iff) );
set_control( iffalse );
}
void Parse::jump_if_false_fork(IfNode *iff, int dest_bci_if_true, bool unc) {
// True branch, use existing map info
{ PreserveJVMState pjvms(this);
Node *iffalse = _gvn.transform( new IfFalseNode (iff) );
set_control( iffalse );
if (unc) {
repush_if_args();
uncommon_trap(Deoptimization::Reason_unstable_if,
Deoptimization::Action_reinterpret,
NULL,
"taken never");
} else {
assert(dest_bci_if_true != never_reached, "inconsistent dest");
merge_new_path(dest_bci_if_true);
}
}
// False branch
Node *iftrue = _gvn.transform( new IfTrueNode(iff) );
set_control( iftrue );
}
void Parse::jump_if_always_fork(int dest_bci, bool unc) {
// False branch, use existing map and control()
if (unc) {
repush_if_args();
uncommon_trap(Deoptimization::Reason_unstable_if,
Deoptimization::Action_reinterpret,
NULL,
"taken never");
} else {
assert(dest_bci != never_reached, "inconsistent dest");
merge_new_path(dest_bci);
}
}
extern "C" {
static int jint_cmp(const void *i, const void *j) {
int a = *(jint *)i;
int b = *(jint *)j;
return a > b ? 1 : a < b ? -1 : 0;
}
}
class SwitchRange : public StackObj {
// a range of integers coupled with a bci destination
jint _lo; // inclusive lower limit
jint _hi; // inclusive upper limit
int _dest;
float _cnt; // how many times this range was hit according to profiling
public:
jint lo() const { return _lo; }
jint hi() const { return _hi; }
int dest() const { return _dest; }
bool is_singleton() const { return _lo == _hi; }
float cnt() const { return _cnt; }
void setRange(jint lo, jint hi, int dest, float cnt) {
assert(lo <= hi, "must be a non-empty range");
_lo = lo, _hi = hi; _dest = dest; _cnt = cnt;
assert(_cnt >= 0, "");
}
bool adjoinRange(jint lo, jint hi, int dest, float cnt, bool trim_ranges) {
assert(lo <= hi, "must be a non-empty range");
if (lo == _hi+1) {
// see merge_ranges() comment below
if (trim_ranges) {
if (cnt == 0) {
if (_cnt != 0) {
return false;
}
if (dest != _dest) {
_dest = never_reached;
}
} else {
if (_cnt == 0) {
return false;
}
if (dest != _dest) {
return false;
}
}
} else {
if (dest != _dest) {
return false;
}
}
_hi = hi;
_cnt += cnt;
return true;
}
return false;
}
void set (jint value, int dest, float cnt) {
setRange(value, value, dest, cnt);
}
bool adjoin(jint value, int dest, float cnt, bool trim_ranges) {
return adjoinRange(value, value, dest, cnt, trim_ranges);
}
bool adjoin(SwitchRange& other) {
return adjoinRange(other._lo, other._hi, other._dest, other._cnt, false);
}
void print() {
if (is_singleton())
tty->print(" {%d}=>%d (cnt=%f)", lo(), dest(), cnt());
else if (lo() == min_jint)
tty->print(" {..%d}=>%d (cnt=%f)", hi(), dest(), cnt());
else if (hi() == max_jint)
tty->print(" {%d..}=>%d (cnt=%f)", lo(), dest(), cnt());
else
tty->print(" {%d..%d}=>%d (cnt=%f)", lo(), hi(), dest(), cnt());
}
};
// We try to minimize the number of ranges and the size of the taken
// ones using profiling data. When ranges are created,
// SwitchRange::adjoinRange() only allows 2 adjoining ranges to merge
// if both were never hit or both were hit to build longer unreached
// ranges. Here, we now merge adjoining ranges with the same
// destination and finally set destination of unreached ranges to the
// special value never_reached because it can help minimize the number
// of tests that are necessary.
//
// For instance:
// [0, 1] to target1 sometimes taken
// [1, 2] to target1 never taken
// [2, 3] to target2 never taken
// would lead to:
// [0, 1] to target1 sometimes taken
// [1, 3] never taken
//
// (first 2 ranges to target1 are not merged)
static void merge_ranges(SwitchRange* ranges, int& rp) {
if (rp == 0) {
return;
}
int shift = 0;
for (int j = 0; j < rp; j++) {
SwitchRange& r1 = ranges[j-shift];
SwitchRange& r2 = ranges[j+1];
if (r1.adjoin(r2)) {
shift++;
} else if (shift > 0) {
ranges[j+1-shift] = r2;
}
}
rp -= shift;
for (int j = 0; j <= rp; j++) {
SwitchRange& r = ranges[j];
if (r.cnt() == 0 && r.dest() != never_reached) {
r.setRange(r.lo(), r.hi(), never_reached, r.cnt());
}
}
}
//-------------------------------do_tableswitch--------------------------------
void Parse::do_tableswitch() {
// Get information about tableswitch
int default_dest = iter().get_dest_table(0);
jint lo_index = iter().get_int_table(1);
jint hi_index = iter().get_int_table(2);
int len = hi_index - lo_index + 1;
if (len < 1) {
// If this is a backward branch, add safepoint
maybe_add_safepoint(default_dest);
pop(); // the effect of the instruction execution on the operand stack
merge(default_dest);
return;
}
ciMethodData* methodData = method()->method_data();
ciMultiBranchData* profile = NULL;
if (methodData->is_mature() && UseSwitchProfiling) {
ciProfileData* data = methodData->bci_to_data(bci());
if (data != NULL && data->is_MultiBranchData()) {
profile = (ciMultiBranchData*)data;
}
}
bool trim_ranges = !C->too_many_traps(method(), bci(), Deoptimization::Reason_unstable_if);
// generate decision tree, using trichotomy when possible
int rnum = len+2;
bool makes_backward_branch = false;
SwitchRange* ranges = NEW_RESOURCE_ARRAY(SwitchRange, rnum);
int rp = -1;
if (lo_index != min_jint) {
float cnt = 1.0F;
if (profile != NULL) {
cnt = (float)profile->default_count() / (hi_index != max_jint ? 2.0F : 1.0F);
}
ranges[++rp].setRange(min_jint, lo_index-1, default_dest, cnt);
}
for (int j = 0; j < len; j++) {
jint match_int = lo_index+j;
int dest = iter().get_dest_table(j+3);
makes_backward_branch |= (dest <= bci());
float cnt = 1.0F;
if (profile != NULL) {
cnt = (float)profile->count_at(j);
}
if (rp < 0 || !ranges[rp].adjoin(match_int, dest, cnt, trim_ranges)) {
ranges[++rp].set(match_int, dest, cnt);
}
}
jint highest = lo_index+(len-1);
assert(ranges[rp].hi() == highest, "");
if (highest != max_jint) {
float cnt = 1.0F;
if (profile != NULL) {
cnt = (float)profile->default_count() / (lo_index != min_jint ? 2.0F : 1.0F);
}
if (!ranges[rp].adjoinRange(highest+1, max_jint, default_dest, cnt, trim_ranges)) {
ranges[++rp].setRange(highest+1, max_jint, default_dest, cnt);
}
}
assert(rp < len+2, "not too many ranges");
if (trim_ranges) {
merge_ranges(ranges, rp);
}
// Safepoint in case if backward branch observed
if (makes_backward_branch) {
add_safepoint();
}
Node* lookup = pop(); // lookup value
jump_switch_ranges(lookup, &ranges[0], &ranges[rp]);
}
//------------------------------do_lookupswitch--------------------------------
void Parse::do_lookupswitch() {
// Get information about lookupswitch
int default_dest = iter().get_dest_table(0);
jint len = iter().get_int_table(1);
if (len < 1) { // If this is a backward branch, add safepoint
maybe_add_safepoint(default_dest);
pop(); // the effect of the instruction execution on the operand stack
merge(default_dest);
return;
}
ciMethodData* methodData = method()->method_data();
ciMultiBranchData* profile = NULL;
if (methodData->is_mature() && UseSwitchProfiling) {
ciProfileData* data = methodData->bci_to_data(bci());
if (data != NULL && data->is_MultiBranchData()) {
profile = (ciMultiBranchData*)data;
}
}
bool trim_ranges = !C->too_many_traps(method(), bci(), Deoptimization::Reason_unstable_if);
// generate decision tree, using trichotomy when possible
jint* table = NEW_RESOURCE_ARRAY(jint, len*3);
{
for (int j = 0; j < len; j++) {
table[3*j+0] = iter().get_int_table(2+2*j);
table[3*j+1] = iter().get_dest_table(2+2*j+1);
// Handle overflow when converting from uint to jint
table[3*j+2] = (profile == NULL) ? 1 : (jint)MIN2<uint>((uint)max_jint, profile->count_at(j));
}
qsort(table, len, 3*sizeof(table[0]), jint_cmp);
}
float default_cnt = 1.0F;
if (profile != NULL) {
juint defaults = max_juint - len;
default_cnt = (float)profile->default_count()/(float)defaults;
}
int rnum = len*2+1;
bool makes_backward_branch = false;
SwitchRange* ranges = NEW_RESOURCE_ARRAY(SwitchRange, rnum);
int rp = -1;
for (int j = 0; j < len; j++) {
jint match_int = table[3*j+0];
jint dest = table[3*j+1];
jint cnt = table[3*j+2];
jint next_lo = rp < 0 ? min_jint : ranges[rp].hi()+1;
makes_backward_branch |= (dest <= bci());
float c = default_cnt * ((float)match_int - (float)next_lo);
if (match_int != next_lo && (rp < 0 || !ranges[rp].adjoinRange(next_lo, match_int-1, default_dest, c, trim_ranges))) {
assert(default_dest != never_reached, "sentinel value for dead destinations");
ranges[++rp].setRange(next_lo, match_int-1, default_dest, c);
}
if (rp < 0 || !ranges[rp].adjoin(match_int, dest, (float)cnt, trim_ranges)) {
assert(dest != never_reached, "sentinel value for dead destinations");
ranges[++rp].set(match_int, dest, (float)cnt);
}
}
jint highest = table[3*(len-1)];
assert(ranges[rp].hi() == highest, "");
if (highest != max_jint &&
!ranges[rp].adjoinRange(highest+1, max_jint, default_dest, default_cnt * ((float)max_jint - (float)highest), trim_ranges)) {
ranges[++rp].setRange(highest+1, max_jint, default_dest, default_cnt * ((float)max_jint - (float)highest));
}
assert(rp < rnum, "not too many ranges");
if (trim_ranges) {
merge_ranges(ranges, rp);
}
// Safepoint in case backward branch observed
if (makes_backward_branch) {
add_safepoint();
}
Node *lookup = pop(); // lookup value
jump_switch_ranges(lookup, &ranges[0], &ranges[rp]);
}
static float if_prob(float taken_cnt, float total_cnt) {
assert(taken_cnt <= total_cnt, "");
if (total_cnt == 0) {
return PROB_FAIR;
}
float p = taken_cnt / total_cnt;
return clamp(p, PROB_MIN, PROB_MAX);
}
static float if_cnt(float cnt) {
if (cnt == 0) {
return COUNT_UNKNOWN;
}
return cnt;
}
static float sum_of_cnts(SwitchRange *lo, SwitchRange *hi) {
float total_cnt = 0;
for (SwitchRange* sr = lo; sr <= hi; sr++) {
total_cnt += sr->cnt();
}
return total_cnt;
}
class SwitchRanges : public ResourceObj {
public:
SwitchRange* _lo;
SwitchRange* _hi;
SwitchRange* _mid;
float _cost;
enum {
Start,
LeftDone,
RightDone,
Done
} _state;
SwitchRanges(SwitchRange *lo, SwitchRange *hi)
: _lo(lo), _hi(hi), _mid(NULL),
_cost(0), _state(Start) {
}
SwitchRanges()
: _lo(NULL), _hi(NULL), _mid(NULL),
_cost(0), _state(Start) {}
};
// Estimate cost of performing a binary search on lo..hi
static float compute_tree_cost(SwitchRange *lo, SwitchRange *hi, float total_cnt) {
GrowableArray<SwitchRanges> tree;
SwitchRanges root(lo, hi);
tree.push(root);
float cost = 0;
do {
SwitchRanges& r = *tree.adr_at(tree.length()-1);
if (r._hi != r._lo) {
if (r._mid == NULL) {
float r_cnt = sum_of_cnts(r._lo, r._hi);
if (r_cnt == 0) {
tree.pop();
cost = 0;
continue;
}
SwitchRange* mid = NULL;
mid = r._lo;
for (float cnt = 0; ; ) {
assert(mid <= r._hi, "out of bounds");
cnt += mid->cnt();
if (cnt > r_cnt / 2) {
break;
}
mid++;
}
assert(mid <= r._hi, "out of bounds");
r._mid = mid;
r._cost = r_cnt / total_cnt;
}
r._cost += cost;
if (r._state < SwitchRanges::LeftDone && r._mid > r._lo) {
cost = 0;
r._state = SwitchRanges::LeftDone;
tree.push(SwitchRanges(r._lo, r._mid-1));
} else if (r._state < SwitchRanges::RightDone) {
cost = 0;
r._state = SwitchRanges::RightDone;
tree.push(SwitchRanges(r._mid == r._lo ? r._mid+1 : r._mid, r._hi));
} else {
tree.pop();
cost = r._cost;
}
} else {
tree.pop();
cost = r._cost;
}
} while (tree.length() > 0);
return cost;
}
// It sometimes pays off to test most common ranges before the binary search
void Parse::linear_search_switch_ranges(Node* key_val, SwitchRange*& lo, SwitchRange*& hi) {
uint nr = hi - lo + 1;
float total_cnt = sum_of_cnts(lo, hi);
float min = compute_tree_cost(lo, hi, total_cnt);
float extra = 1;
float sub = 0;
SwitchRange* array1 = lo;
SwitchRange* array2 = NEW_RESOURCE_ARRAY(SwitchRange, nr);
SwitchRange* ranges = NULL;
while (nr >= 2) {
assert(lo == array1 || lo == array2, "one the 2 already allocated arrays");
ranges = (lo == array1) ? array2 : array1;
// Find highest frequency range
SwitchRange* candidate = lo;
for (SwitchRange* sr = lo+1; sr <= hi; sr++) {
if (sr->cnt() > candidate->cnt()) {
candidate = sr;
}
}
SwitchRange most_freq = *candidate;
if (most_freq.cnt() == 0) {
break;
}
// Copy remaining ranges into another array
int shift = 0;
for (uint i = 0; i < nr; i++) {
SwitchRange* sr = &lo[i];
if (sr != candidate) {
ranges[i-shift] = *sr;
} else {
shift++;
if (i > 0 && i < nr-1) {
SwitchRange prev = lo[i-1];
prev.setRange(prev.lo(), sr->hi(), prev.dest(), prev.cnt());
if (prev.adjoin(lo[i+1])) {
shift++;
i++;
}
ranges[i-shift] = prev;
}
}
}
nr -= shift;
// Evaluate cost of testing the most common range and performing a
// binary search on the other ranges
float cost = extra + compute_tree_cost(&ranges[0], &ranges[nr-1], total_cnt);
if (cost >= min) {
break;
}
// swap arrays
lo = &ranges[0];
hi = &ranges[nr-1];
// It pays off: emit the test for the most common range
assert(most_freq.cnt() > 0, "must be taken");
Node* val = _gvn.transform(new SubINode(key_val, _gvn.intcon(most_freq.lo())));
Node* cmp = _gvn.transform(new CmpUNode(val, _gvn.intcon(most_freq.hi() - most_freq.lo())));
Node* tst = _gvn.transform(new BoolNode(cmp, BoolTest::le));
IfNode* iff = create_and_map_if(control(), tst, if_prob(most_freq.cnt(), total_cnt), if_cnt(most_freq.cnt()));
jump_if_true_fork(iff, most_freq.dest(), false);
sub += most_freq.cnt() / total_cnt;
extra += 1 - sub;
min = cost;
}
}
//----------------------------create_jump_tables-------------------------------
bool Parse::create_jump_tables(Node* key_val, SwitchRange* lo, SwitchRange* hi) {
// Are jumptables enabled
if (!UseJumpTables) return false;
// Are jumptables supported
if (!Matcher::has_match_rule(Op_Jump)) return false;
bool trim_ranges = !C->too_many_traps(method(), bci(), Deoptimization::Reason_unstable_if);
// Decide if a guard is needed to lop off big ranges at either (or
// both) end(s) of the input set. We'll call this the default target
// even though we can't be sure that it is the true "default".
bool needs_guard = false;
int default_dest;
int64_t total_outlier_size = 0;
int64_t hi_size = ((int64_t)hi->hi()) - ((int64_t)hi->lo()) + 1;
int64_t lo_size = ((int64_t)lo->hi()) - ((int64_t)lo->lo()) + 1;
if (lo->dest() == hi->dest()) {
total_outlier_size = hi_size + lo_size;
default_dest = lo->dest();
} else if (lo_size > hi_size) {
total_outlier_size = lo_size;
default_dest = lo->dest();
} else {
total_outlier_size = hi_size;
default_dest = hi->dest();
}
float total = sum_of_cnts(lo, hi);
float cost = compute_tree_cost(lo, hi, total);
// If a guard test will eliminate very sparse end ranges, then
// it is worth the cost of an extra jump.
float trimmed_cnt = 0;
if (total_outlier_size > (MaxJumpTableSparseness * 4)) {
needs_guard = true;
if (default_dest == lo->dest()) {
trimmed_cnt += lo->cnt();
lo++;
}
if (default_dest == hi->dest()) {
trimmed_cnt += hi->cnt();
hi--;
}
}
// Find the total number of cases and ranges
int64_t num_cases = ((int64_t)hi->hi()) - ((int64_t)lo->lo()) + 1;
int num_range = hi - lo + 1;
// Don't create table if: too large, too small, or too sparse.
if (num_cases > MaxJumpTableSize)
return false;
if (UseSwitchProfiling) {
// MinJumpTableSize is set so with a well balanced binary tree,
// when the number of ranges is MinJumpTableSize, it's cheaper to
// go through a JumpNode that a tree of IfNodes. Average cost of a
// tree of IfNodes with MinJumpTableSize is
// log2f(MinJumpTableSize) comparisons. So if the cost computed
// from profile data is less than log2f(MinJumpTableSize) then
// going with the binary search is cheaper.
if (cost < log2f(MinJumpTableSize)) {
return false;
}
} else {
if (num_cases < MinJumpTableSize)
return false;
}
if (num_cases > (MaxJumpTableSparseness * num_range))
return false;
// Normalize table lookups to zero
int lowval = lo->lo();
key_val = _gvn.transform( new SubINode(key_val, _gvn.intcon(lowval)) );
// Generate a guard to protect against input keyvals that aren't
// in the switch domain.
if (needs_guard) {
Node* size = _gvn.intcon(num_cases);
Node* cmp = _gvn.transform(new CmpUNode(key_val, size));
Node* tst = _gvn.transform(new BoolNode(cmp, BoolTest::ge));
IfNode* iff = create_and_map_if(control(), tst, if_prob(trimmed_cnt, total), if_cnt(trimmed_cnt));
jump_if_true_fork(iff, default_dest, trim_ranges && trimmed_cnt == 0);
total -= trimmed_cnt;
}
// Create an ideal node JumpTable that has projections
// of all possible ranges for a switch statement
// The key_val input must be converted to a pointer offset and scaled.
// Compare Parse::array_addressing above.
// Clean the 32-bit int into a real 64-bit offset.
// Otherwise, the jint value 0 might turn into an offset of 0x0800000000.
// Make I2L conversion control dependent to prevent it from
// floating above the range check during loop optimizations.
// Do not use a narrow int type here to prevent the data path from dying
// while the control path is not removed. This can happen if the type of key_val
// is later known to be out of bounds of [0, num_cases] and therefore a narrow cast
// would be replaced by TOP while C2 is not able to fold the corresponding range checks.
// Set _carry_dependency for the cast to avoid being removed by IGVN.
#ifdef _LP64
key_val = C->constrained_convI2L(&_gvn, key_val, TypeInt::INT, control(), true /* carry_dependency */);
#endif
// Shift the value by wordsize so we have an index into the table, rather
// than a switch value
Node *shiftWord = _gvn.MakeConX(wordSize);
key_val = _gvn.transform( new MulXNode( key_val, shiftWord));
// Create the JumpNode
Arena* arena = C->comp_arena();
float* probs = (float*)arena->Amalloc(sizeof(float)*num_cases);
int i = 0;
if (total == 0) {
for (SwitchRange* r = lo; r <= hi; r++) {
for (int64_t j = r->lo(); j <= r->hi(); j++, i++) {
probs[i] = 1.0F / num_cases;
}
}
} else {
for (SwitchRange* r = lo; r <= hi; r++) {
float prob = r->cnt()/total;
for (int64_t j = r->lo(); j <= r->hi(); j++, i++) {
probs[i] = prob / (r->hi() - r->lo() + 1);
}
}
}
ciMethodData* methodData = method()->method_data();
ciMultiBranchData* profile = NULL;
if (methodData->is_mature()) {
ciProfileData* data = methodData->bci_to_data(bci());
if (data != NULL && data->is_MultiBranchData()) {
profile = (ciMultiBranchData*)data;
}
}
Node* jtn = _gvn.transform(new JumpNode(control(), key_val, num_cases, probs, profile == NULL ? COUNT_UNKNOWN : total));
// These are the switch destinations hanging off the jumpnode
i = 0;
for (SwitchRange* r = lo; r <= hi; r++) {
for (int64_t j = r->lo(); j <= r->hi(); j++, i++) {
Node* input = _gvn.transform(new JumpProjNode(jtn, i, r->dest(), (int)(j - lowval)));
{
PreserveJVMState pjvms(this);
set_control(input);
jump_if_always_fork(r->dest(), trim_ranges && r->cnt() == 0);
}
}
}
assert(i == num_cases, "miscount of cases");
stop_and_kill_map(); // no more uses for this JVMS
return true;
}
//----------------------------jump_switch_ranges-------------------------------
void Parse::jump_switch_ranges(Node* key_val, SwitchRange *lo, SwitchRange *hi, int switch_depth) {
Block* switch_block = block();
bool trim_ranges = !C->too_many_traps(method(), bci(), Deoptimization::Reason_unstable_if);
if (switch_depth == 0) {
// Do special processing for the top-level call.
assert(lo->lo() == min_jint, "initial range must exhaust Type::INT");
assert(hi->hi() == max_jint, "initial range must exhaust Type::INT");
// Decrement pred-numbers for the unique set of nodes.
#ifdef ASSERT
if (!trim_ranges) {
// Ensure that the block's successors are a (duplicate-free) set.
int successors_counted = 0; // block occurrences in [hi..lo]
int unique_successors = switch_block->num_successors();
for (int i = 0; i < unique_successors; i++) {
Block* target = switch_block->successor_at(i);
// Check that the set of successors is the same in both places.
int successors_found = 0;
for (SwitchRange* p = lo; p <= hi; p++) {
if (p->dest() == target->start()) successors_found++;
}
assert(successors_found > 0, "successor must be known");
successors_counted += successors_found;
}
assert(successors_counted == (hi-lo)+1, "no unexpected successors");
}
#endif
// Maybe prune the inputs, based on the type of key_val.
jint min_val = min_jint;
jint max_val = max_jint;
const TypeInt* ti = key_val->bottom_type()->isa_int();
if (ti != NULL) {
min_val = ti->_lo;
max_val = ti->_hi;
assert(min_val <= max_val, "invalid int type");
}
while (lo->hi() < min_val) {
lo++;
}
if (lo->lo() < min_val) {
lo->setRange(min_val, lo->hi(), lo->dest(), lo->cnt());
}
while (hi->lo() > max_val) {
hi--;
}
if (hi->hi() > max_val) {
hi->setRange(hi->lo(), max_val, hi->dest(), hi->cnt());
}
linear_search_switch_ranges(key_val, lo, hi);
}
#ifndef PRODUCT
if (switch_depth == 0) {
_max_switch_depth = 0;
_est_switch_depth = log2i_graceful((hi - lo + 1) - 1) + 1;
}
#endif
assert(lo <= hi, "must be a non-empty set of ranges");
if (lo == hi) {
jump_if_always_fork(lo->dest(), trim_ranges && lo->cnt() == 0);
} else {
assert(lo->hi() == (lo+1)->lo()-1, "contiguous ranges");
assert(hi->lo() == (hi-1)->hi()+1, "contiguous ranges");
if (create_jump_tables(key_val, lo, hi)) return;
SwitchRange* mid = NULL;
float total_cnt = sum_of_cnts(lo, hi);
int nr = hi - lo + 1;
if (UseSwitchProfiling) {
// Don't keep the binary search tree balanced: pick up mid point
// that split frequencies in half.
float cnt = 0;
for (SwitchRange* sr = lo; sr <= hi; sr++) {
cnt += sr->cnt();
if (cnt >= total_cnt / 2) {
mid = sr;
break;
}
}
} else {
mid = lo + nr/2;
// if there is an easy choice, pivot at a singleton:
if (nr > 3 && !mid->is_singleton() && (mid-1)->is_singleton()) mid--;
assert(lo < mid && mid <= hi, "good pivot choice");
assert(nr != 2 || mid == hi, "should pick higher of 2");
assert(nr != 3 || mid == hi-1, "should pick middle of 3");
}
Node *test_val = _gvn.intcon(mid == lo ? mid->hi() : mid->lo());
if (mid->is_singleton()) {
IfNode *iff_ne = jump_if_fork_int(key_val, test_val, BoolTest::ne, 1-if_prob(mid->cnt(), total_cnt), if_cnt(mid->cnt()));
jump_if_false_fork(iff_ne, mid->dest(), trim_ranges && mid->cnt() == 0);
// Special Case: If there are exactly three ranges, and the high
// and low range each go to the same place, omit the "gt" test,
// since it will not discriminate anything.
bool eq_test_only = (hi == lo+2 && hi->dest() == lo->dest() && mid == hi-1) || mid == lo;
// if there is a higher range, test for it and process it:
if (mid < hi && !eq_test_only) {
// two comparisons of same values--should enable 1 test for 2 branches
// Use BoolTest::lt instead of BoolTest::gt
float cnt = sum_of_cnts(lo, mid-1);
IfNode *iff_lt = jump_if_fork_int(key_val, test_val, BoolTest::lt, if_prob(cnt, total_cnt), if_cnt(cnt));
Node *iftrue = _gvn.transform( new IfTrueNode(iff_lt) );
Node *iffalse = _gvn.transform( new IfFalseNode(iff_lt) );
{ PreserveJVMState pjvms(this);
set_control(iffalse);
jump_switch_ranges(key_val, mid+1, hi, switch_depth+1);
}
set_control(iftrue);
}
} else {
// mid is a range, not a singleton, so treat mid..hi as a unit
float cnt = sum_of_cnts(mid == lo ? mid+1 : mid, hi);
IfNode *iff_ge = jump_if_fork_int(key_val, test_val, mid == lo ? BoolTest::gt : BoolTest::ge, if_prob(cnt, total_cnt), if_cnt(cnt));
// if there is a higher range, test for it and process it:
if (mid == hi) {
jump_if_true_fork(iff_ge, mid->dest(), trim_ranges && cnt == 0);
} else {
Node *iftrue = _gvn.transform( new IfTrueNode(iff_ge) );
Node *iffalse = _gvn.transform( new IfFalseNode(iff_ge) );
{ PreserveJVMState pjvms(this);
set_control(iftrue);
jump_switch_ranges(key_val, mid == lo ? mid+1 : mid, hi, switch_depth+1);
}
set_control(iffalse);
}
}
// in any case, process the lower range
if (mid == lo) {
if (mid->is_singleton()) {
jump_switch_ranges(key_val, lo+1, hi, switch_depth+1);
} else {
jump_if_always_fork(lo->dest(), trim_ranges && lo->cnt() == 0);
}
} else {
jump_switch_ranges(key_val, lo, mid-1, switch_depth+1);
}
}
// Decrease pred_count for each successor after all is done.
if (switch_depth == 0) {
int unique_successors = switch_block->num_successors();
for (int i = 0; i < unique_successors; i++) {
Block* target = switch_block->successor_at(i);
// Throw away the pre-allocated path for each unique successor.
target->next_path_num();
}
}
#ifndef PRODUCT
_max_switch_depth = MAX2(switch_depth, _max_switch_depth);
if (TraceOptoParse && Verbose && WizardMode && switch_depth == 0) {
SwitchRange* r;
int nsing = 0;
for( r = lo; r <= hi; r++ ) {
if( r->is_singleton() ) nsing++;
}
tty->print(">>> ");
_method->print_short_name();
tty->print_cr(" switch decision tree");
tty->print_cr(" %d ranges (%d singletons), max_depth=%d, est_depth=%d",
(int) (hi-lo+1), nsing, _max_switch_depth, _est_switch_depth);
if (_max_switch_depth > _est_switch_depth) {
tty->print_cr("******** BAD SWITCH DEPTH ********");
}
tty->print(" ");
for( r = lo; r <= hi; r++ ) {
r->print();
}
tty->cr();
}
#endif
}
void Parse::modf() {
Node *f2 = pop();
Node *f1 = pop();
Node* c = make_runtime_call(RC_LEAF, OptoRuntime::modf_Type(),
CAST_FROM_FN_PTR(address, SharedRuntime::frem),
"frem", NULL, //no memory effects
f1, f2);
Node* res = _gvn.transform(new ProjNode(c, TypeFunc::Parms + 0));
push(res);
}
void Parse::modd() {
Node *d2 = pop_pair();
Node *d1 = pop_pair();
Node* c = make_runtime_call(RC_LEAF, OptoRuntime::Math_DD_D_Type(),
CAST_FROM_FN_PTR(address, SharedRuntime::drem),
"drem", NULL, //no memory effects
d1, top(), d2, top());
Node* res_d = _gvn.transform(new ProjNode(c, TypeFunc::Parms + 0));
#ifdef ASSERT
Node* res_top = _gvn.transform(new ProjNode(c, TypeFunc::Parms + 1));
assert(res_top == top(), "second value must be top");
#endif
push_pair(res_d);
}
void Parse::l2f() {
Node* f2 = pop();
Node* f1 = pop();
Node* c = make_runtime_call(RC_LEAF, OptoRuntime::l2f_Type(),
CAST_FROM_FN_PTR(address, SharedRuntime::l2f),
"l2f", NULL, //no memory effects
f1, f2);
Node* res = _gvn.transform(new ProjNode(c, TypeFunc::Parms + 0));
push(res);
}
// Handle jsr and jsr_w bytecode
void Parse::do_jsr() {
assert(bc() == Bytecodes::_jsr || bc() == Bytecodes::_jsr_w, "wrong bytecode");
// Store information about current state, tagged with new _jsr_bci
int return_bci = iter().next_bci();
int jsr_bci = (bc() == Bytecodes::_jsr) ? iter().get_dest() : iter().get_far_dest();
// The way we do things now, there is only one successor block
// for the jsr, because the target code is cloned by ciTypeFlow.
Block* target = successor_for_bci(jsr_bci);
// What got pushed?
const Type* ret_addr = target->peek();
assert(ret_addr->singleton(), "must be a constant (cloned jsr body)");
// Effect on jsr on stack
push(_gvn.makecon(ret_addr));
// Flow to the jsr.
merge(jsr_bci);
}
// Handle ret bytecode
void Parse::do_ret() {
// Find to whom we return.
assert(block()->num_successors() == 1, "a ret can only go one place now");
Block* target = block()->successor_at(0);
assert(!target->is_ready(), "our arrival must be expected");
int pnum = target->next_path_num();
merge_common(target, pnum);
}
static bool has_injected_profile(BoolTest::mask btest, Node* test, int& taken, int& not_taken) {
if (btest != BoolTest::eq && btest != BoolTest::ne) {
// Only ::eq and ::ne are supported for profile injection.
return false;
}
if (test->is_Cmp() &&
test->in(1)->Opcode() == Op_ProfileBoolean) {
ProfileBooleanNode* profile = (ProfileBooleanNode*)test->in(1);
int false_cnt = profile->false_count();
int true_cnt = profile->true_count();
// Counts matching depends on the actual test operation (::eq or ::ne).
// No need to scale the counts because profile injection was designed
// to feed exact counts into VM.
taken = (btest == BoolTest::eq) ? false_cnt : true_cnt;
not_taken = (btest == BoolTest::eq) ? true_cnt : false_cnt;
profile->consume();
return true;
}
return false;
}
//--------------------------dynamic_branch_prediction--------------------------
// Try to gather dynamic branch prediction behavior. Return a probability
// of the branch being taken and set the "cnt" field. Returns a -1.0
// if we need to use static prediction for some reason.
float Parse::dynamic_branch_prediction(float &cnt, BoolTest::mask btest, Node* test) {
ResourceMark rm;
cnt = COUNT_UNKNOWN;
int taken = 0;
int not_taken = 0;
bool use_mdo = !has_injected_profile(btest, test, taken, not_taken);
if (use_mdo) {
// Use MethodData information if it is available
// FIXME: free the ProfileData structure
ciMethodData* methodData = method()->method_data();
if (!methodData->is_mature()) return PROB_UNKNOWN;
ciProfileData* data = methodData->bci_to_data(bci());
if (data == NULL) {
return PROB_UNKNOWN;
}
if (!data->is_JumpData()) return PROB_UNKNOWN;
// get taken and not taken values
taken = data->as_JumpData()->taken();
not_taken = 0;
if (data->is_BranchData()) {
not_taken = data->as_BranchData()->not_taken();
}
// scale the counts to be commensurate with invocation counts:
taken = method()->scale_count(taken);
not_taken = method()->scale_count(not_taken);
}
// Give up if too few (or too many, in which case the sum will overflow) counts to be meaningful.
// We also check that individual counters are positive first, otherwise the sum can become positive.
if (taken < 0 || not_taken < 0 || taken + not_taken < 40) {
if (C->log() != NULL) {
C->log()->elem("branch target_bci='%d' taken='%d' not_taken='%d'", iter().get_dest(), taken, not_taken);
}
return PROB_UNKNOWN;
}
// Compute frequency that we arrive here
float sum = taken + not_taken;
// Adjust, if this block is a cloned private block but the
// Jump counts are shared. Taken the private counts for
// just this path instead of the shared counts.
if( block()->count() > 0 )
sum = block()->count();
cnt = sum / FreqCountInvocations;
// Pin probability to sane limits
float prob;
if( !taken )
prob = (0+PROB_MIN) / 2;
else if( !not_taken )
prob = (1+PROB_MAX) / 2;
else { // Compute probability of true path
prob = (float)taken / (float)(taken + not_taken);
if (prob > PROB_MAX) prob = PROB_MAX;
if (prob < PROB_MIN) prob = PROB_MIN;
}
assert((cnt > 0.0f) && (prob > 0.0f),
"Bad frequency assignment in if");
if (C->log() != NULL) {
const char* prob_str = NULL;
if (prob >= PROB_MAX) prob_str = (prob == PROB_MAX) ? "max" : "always";
if (prob <= PROB_MIN) prob_str = (prob == PROB_MIN) ? "min" : "never";
char prob_str_buf[30];
if (prob_str == NULL) {
jio_snprintf(prob_str_buf, sizeof(prob_str_buf), "%20.2f", prob);
prob_str = prob_str_buf;
}
C->log()->elem("branch target_bci='%d' taken='%d' not_taken='%d' cnt='%f' prob='%s'",
iter().get_dest(), taken, not_taken, cnt, prob_str);
}
return prob;
}
//-----------------------------branch_prediction-------------------------------
float Parse::branch_prediction(float& cnt,
BoolTest::mask btest,
int target_bci,
Node* test) {
float prob = dynamic_branch_prediction(cnt, btest, test);
// If prob is unknown, switch to static prediction
if (prob != PROB_UNKNOWN) return prob;
prob = PROB_FAIR; // Set default value
if (btest == BoolTest::eq) // Exactly equal test?
prob = PROB_STATIC_INFREQUENT; // Assume its relatively infrequent
else if (btest == BoolTest::ne)
prob = PROB_STATIC_FREQUENT; // Assume its relatively frequent
// If this is a conditional test guarding a backwards branch,
// assume its a loop-back edge. Make it a likely taken branch.
if (target_bci < bci()) {
if (is_osr_parse()) { // Could be a hot OSR'd loop; force deopt
// Since it's an OSR, we probably have profile data, but since
// branch_prediction returned PROB_UNKNOWN, the counts are too small.
// Let's make a special check here for completely zero counts.
ciMethodData* methodData = method()->method_data();
if (!methodData->is_empty()) {
ciProfileData* data = methodData->bci_to_data(bci());
// Only stop for truly zero counts, which mean an unknown part
// of the OSR-ed method, and we want to deopt to gather more stats.
// If you have ANY counts, then this loop is simply 'cold' relative
// to the OSR loop.
if (data == NULL ||
(data->as_BranchData()->taken() + data->as_BranchData()->not_taken() == 0)) {
// This is the only way to return PROB_UNKNOWN:
return PROB_UNKNOWN;
}
}
}
prob = PROB_STATIC_FREQUENT; // Likely to take backwards branch
}
assert(prob != PROB_UNKNOWN, "must have some guess at this point");
return prob;
}
// The magic constants are chosen so as to match the output of
// branch_prediction() when the profile reports a zero taken count.
// It is important to distinguish zero counts unambiguously, because
// some branches (e.g., _213_javac.Assembler.eliminate) validly produce
// very small but nonzero probabilities, which if confused with zero
// counts would keep the program recompiling indefinitely.
bool Parse::seems_never_taken(float prob) const {
return prob < PROB_MIN;
}
// True if the comparison seems to be the kind that will not change its
// statistics from true to false. See comments in adjust_map_after_if.
// This question is only asked along paths which are already
// classified as untaken (by seems_never_taken), so really,
// if a path is never taken, its controlling comparison is
// already acting in a stable fashion. If the comparison
// seems stable, we will put an expensive uncommon trap
// on the untaken path.
bool Parse::seems_stable_comparison() const {
if (C->too_many_traps(method(), bci(), Deoptimization::Reason_unstable_if)) {
return false;
}
return true;
}
//-------------------------------repush_if_args--------------------------------
// Push arguments of an "if" bytecode back onto the stack by adjusting _sp.
inline int Parse::repush_if_args() {
if (PrintOpto && WizardMode) {
tty->print("defending against excessive implicit null exceptions on %s @%d in ",
Bytecodes::name(iter().cur_bc()), iter().cur_bci());
method()->print_name(); tty->cr();
}
int bc_depth = - Bytecodes::depth(iter().cur_bc());
assert(bc_depth == 1 || bc_depth == 2, "only two kinds of branches");
DEBUG_ONLY(sync_jvms()); // argument(n) requires a synced jvms
assert(argument(0) != NULL, "must exist");
assert(bc_depth == 1 || argument(1) != NULL, "two must exist");
inc_sp(bc_depth);
return bc_depth;
}
//----------------------------------do_ifnull----------------------------------
void Parse::do_ifnull(BoolTest::mask btest, Node *c) {
int target_bci = iter().get_dest();
Block* branch_block = successor_for_bci(target_bci);
Block* next_block = successor_for_bci(iter().next_bci());
float cnt;
float prob = branch_prediction(cnt, btest, target_bci, c);
if (prob == PROB_UNKNOWN) {
// (An earlier version of do_ifnull omitted this trap for OSR methods.)
if (PrintOpto && Verbose) {
tty->print_cr("Never-taken edge stops compilation at bci %d", bci());
}
repush_if_args(); // to gather stats on loop
uncommon_trap(Deoptimization::Reason_unreached,
Deoptimization::Action_reinterpret,
NULL, "cold");
if (C->eliminate_boxing()) {
// Mark the successor blocks as parsed
branch_block->next_path_num();
next_block->next_path_num();
}
return;
}
NOT_PRODUCT(explicit_null_checks_inserted++);
// Generate real control flow
Node *tst = _gvn.transform( new BoolNode( c, btest ) );
// Sanity check the probability value
assert(prob > 0.0f,"Bad probability in Parser");
// Need xform to put node in hash table
IfNode *iff = create_and_xform_if( control(), tst, prob, cnt );
assert(iff->_prob > 0.0f,"Optimizer made bad probability in parser");
// True branch
{ PreserveJVMState pjvms(this);
Node* iftrue = _gvn.transform( new IfTrueNode (iff) );
set_control(iftrue);
if (stopped()) { // Path is dead?
NOT_PRODUCT(explicit_null_checks_elided++);
if (C->eliminate_boxing()) {
// Mark the successor block as parsed
branch_block->next_path_num();
}
} else { // Path is live.
adjust_map_after_if(btest, c, prob, branch_block);
if (!stopped()) {
merge(target_bci);
}
}
}
// False branch
Node* iffalse = _gvn.transform( new IfFalseNode(iff) );
set_control(iffalse);
if (stopped()) { // Path is dead?
NOT_PRODUCT(explicit_null_checks_elided++);
if (C->eliminate_boxing()) {
// Mark the successor block as parsed
next_block->next_path_num();
}
} else { // Path is live.
adjust_map_after_if(BoolTest(btest).negate(), c, 1.0-prob, next_block);
}
}
//------------------------------------do_if------------------------------------
void Parse::do_if(BoolTest::mask btest, Node* c) {
int target_bci = iter().get_dest();
Block* branch_block = successor_for_bci(target_bci);
Block* next_block = successor_for_bci(iter().next_bci());
float cnt;
float prob = branch_prediction(cnt, btest, target_bci, c);
float untaken_prob = 1.0 - prob;
if (prob == PROB_UNKNOWN) {
if (PrintOpto && Verbose) {
tty->print_cr("Never-taken edge stops compilation at bci %d", bci());
}
repush_if_args(); // to gather stats on loop
uncommon_trap(Deoptimization::Reason_unreached,
Deoptimization::Action_reinterpret,
NULL, "cold");
if (C->eliminate_boxing()) {
// Mark the successor blocks as parsed
branch_block->next_path_num();
next_block->next_path_num();
}
return;
}
// Sanity check the probability value
assert(0.0f < prob && prob < 1.0f,"Bad probability in Parser");
bool taken_if_true = true;
// Convert BoolTest to canonical form:
if (!BoolTest(btest).is_canonical()) {
btest = BoolTest(btest).negate();
taken_if_true = false;
// prob is NOT updated here; it remains the probability of the taken
// path (as opposed to the prob of the path guarded by an 'IfTrueNode').
}
assert(btest != BoolTest::eq, "!= is the only canonical exact test");
Node* tst0 = new BoolNode(c, btest);
Node* tst = _gvn.transform(tst0);
BoolTest::mask taken_btest = BoolTest::illegal;
BoolTest::mask untaken_btest = BoolTest::illegal;
if (tst->is_Bool()) {
// Refresh c from the transformed bool node, since it may be
// simpler than the original c. Also re-canonicalize btest.
// This wins when (Bool ne (Conv2B p) 0) => (Bool ne (CmpP p NULL)).
// That can arise from statements like: if (x instanceof C) ...
if (tst != tst0) {
// Canonicalize one more time since transform can change it.
btest = tst->as_Bool()->_test._test;
if (!BoolTest(btest).is_canonical()) {
// Reverse edges one more time...
tst = _gvn.transform( tst->as_Bool()->negate(&_gvn) );
btest = tst->as_Bool()->_test._test;
assert(BoolTest(btest).is_canonical(), "sanity");
taken_if_true = !taken_if_true;
}
c = tst->in(1);
}
BoolTest::mask neg_btest = BoolTest(btest).negate();
taken_btest = taken_if_true ? btest : neg_btest;
untaken_btest = taken_if_true ? neg_btest : btest;
}
// Generate real control flow
float true_prob = (taken_if_true ? prob : untaken_prob);
IfNode* iff = create_and_map_if(control(), tst, true_prob, cnt);
assert(iff->_prob > 0.0f,"Optimizer made bad probability in parser");
Node* taken_branch = new IfTrueNode(iff);
Node* untaken_branch = new IfFalseNode(iff);
if (!taken_if_true) { // Finish conversion to canonical form
Node* tmp = taken_branch;
taken_branch = untaken_branch;
untaken_branch = tmp;
}
// Branch is taken:
{ PreserveJVMState pjvms(this);
taken_branch = _gvn.transform(taken_branch);
set_control(taken_branch);
if (stopped()) {
if (C->eliminate_boxing()) {
// Mark the successor block as parsed
branch_block->next_path_num();
}
} else {
adjust_map_after_if(taken_btest, c, prob, branch_block);
if (!stopped()) {
merge(target_bci);
}
}
}
untaken_branch = _gvn.transform(untaken_branch);
set_control(untaken_branch);
// Branch not taken.
if (stopped()) {
if (C->eliminate_boxing()) {
// Mark the successor block as parsed
next_block->next_path_num();
}
} else {
adjust_map_after_if(untaken_btest, c, untaken_prob, next_block);
}
}
bool Parse::path_is_suitable_for_uncommon_trap(float prob) const {
// Don't want to speculate on uncommon traps when running with -Xcomp
if (!UseInterpreter) {
return false;
}
return (seems_never_taken(prob) && seems_stable_comparison());
}
void Parse::maybe_add_predicate_after_if(Block* path) {
if (path->is_SEL_head() && path->preds_parsed() == 0) {
// Add predicates at bci of if dominating the loop so traps can be
// recorded on the if's profile data
int bc_depth = repush_if_args();
add_empty_predicates();
dec_sp(bc_depth);
path->set_has_predicates();
}
}
//----------------------------adjust_map_after_if------------------------------
// Adjust the JVM state to reflect the result of taking this path.
// Basically, it means inspecting the CmpNode controlling this
// branch, seeing how it constrains a tested value, and then
// deciding if it's worth our while to encode this constraint
// as graph nodes in the current abstract interpretation map.
void Parse::adjust_map_after_if(BoolTest::mask btest, Node* c, float prob, Block* path) {
if (!c->is_Cmp()) {
maybe_add_predicate_after_if(path);
return;
}
if (stopped() || btest == BoolTest::illegal) {
return; // nothing to do
}
bool is_fallthrough = (path == successor_for_bci(iter().next_bci()));
if (path_is_suitable_for_uncommon_trap(prob)) {
repush_if_args();
Node* call = uncommon_trap(Deoptimization::Reason_unstable_if,
Deoptimization::Action_reinterpret,
NULL,
(is_fallthrough ? "taken always" : "taken never"));
if (call != nullptr) {
C->record_unstable_if_trap(new UnstableIfTrap(call->as_CallStaticJava(), path));
}
return;
}
Node* val = c->in(1);
Node* con = c->in(2);
const Type* tcon = _gvn.type(con);
const Type* tval = _gvn.type(val);
bool have_con = tcon->singleton();
if (tval->singleton()) {
if (!have_con) {
// Swap, so constant is in con.
con = val;
tcon = tval;
val = c->in(2);
tval = _gvn.type(val);
btest = BoolTest(btest).commute();
have_con = true;
} else {
// Do we have two constants? Then leave well enough alone.
have_con = false;
}
}
if (!have_con) { // remaining adjustments need a con
maybe_add_predicate_after_if(path);
return;
}
sharpen_type_after_if(btest, con, tcon, val, tval);
maybe_add_predicate_after_if(path);
}
static Node* extract_obj_from_klass_load(PhaseGVN* gvn, Node* n) {
Node* ldk;
if (n->is_DecodeNKlass()) {
if (n->in(1)->Opcode() != Op_LoadNKlass) {
return NULL;
} else {
ldk = n->in(1);
}
} else if (n->Opcode() != Op_LoadKlass) {
return NULL;
} else {
ldk = n;
}
assert(ldk != NULL && ldk->is_Load(), "should have found a LoadKlass or LoadNKlass node");
Node* adr = ldk->in(MemNode::Address);
intptr_t off = 0;
Node* obj = AddPNode::Ideal_base_and_offset(adr, gvn, off);
if (obj == NULL || off != oopDesc::klass_offset_in_bytes()) // loading oopDesc::_klass?
return NULL;
const TypePtr* tp = gvn->type(obj)->is_ptr();
if (tp == NULL || !(tp->isa_instptr() || tp->isa_aryptr())) // is obj a Java object ptr?
return NULL;
return obj;
}
void Parse::sharpen_type_after_if(BoolTest::mask btest,
Node* con, const Type* tcon,
Node* val, const Type* tval) {
// Look for opportunities to sharpen the type of a node
// whose klass is compared with a constant klass.
if (btest == BoolTest::eq && tcon->isa_klassptr()) {
Node* obj = extract_obj_from_klass_load(&_gvn, val);
const TypeOopPtr* con_type = tcon->isa_klassptr()->as_instance_type();
if (obj != NULL && (con_type->isa_instptr() || con_type->isa_aryptr())) {
// Found:
// Bool(CmpP(LoadKlass(obj._klass), ConP(Foo.klass)), [eq])
// or the narrowOop equivalent.
const Type* obj_type = _gvn.type(obj);
const TypeOopPtr* tboth = obj_type->join_speculative(con_type)->isa_oopptr();
if (tboth != NULL && tboth->klass_is_exact() && tboth != obj_type &&
tboth->higher_equal(obj_type)) {
// obj has to be of the exact type Foo if the CmpP succeeds.
int obj_in_map = map()->find_edge(obj);
JVMState* jvms = this->jvms();
if (obj_in_map >= 0 &&
(jvms->is_loc(obj_in_map) || jvms->is_stk(obj_in_map))) {
TypeNode* ccast = new CheckCastPPNode(control(), obj, tboth);
const Type* tcc = ccast->as_Type()->type();
assert(tcc != obj_type && tcc->higher_equal(obj_type), "must improve");
// Delay transform() call to allow recovery of pre-cast value
// at the control merge.
_gvn.set_type_bottom(ccast);
record_for_igvn(ccast);
// Here's the payoff.
replace_in_map(obj, ccast);
}
}
}
}
int val_in_map = map()->find_edge(val);
if (val_in_map < 0) return; // replace_in_map would be useless
{
JVMState* jvms = this->jvms();
if (!(jvms->is_loc(val_in_map) ||
jvms->is_stk(val_in_map)))
return; // again, it would be useless
}
// Check for a comparison to a constant, and "know" that the compared
// value is constrained on this path.
assert(tcon->singleton(), "");
ConstraintCastNode* ccast = NULL;
Node* cast = NULL;
switch (btest) {
case BoolTest::eq: // Constant test?
{
const Type* tboth = tcon->join_speculative(tval);
if (tboth == tval) break; // Nothing to gain.
if (tcon->isa_int()) {
ccast = new CastIINode(val, tboth);
} else if (tcon == TypePtr::NULL_PTR) {
// Cast to null, but keep the pointer identity temporarily live.
ccast = new CastPPNode(val, tboth);
} else {
const TypeF* tf = tcon->isa_float_constant();
const TypeD* td = tcon->isa_double_constant();
// Exclude tests vs float/double 0 as these could be
// either +0 or -0. Just because you are equal to +0
// doesn't mean you ARE +0!
// Note, following code also replaces Long and Oop values.
if ((!tf || tf->_f != 0.0) &&
(!td || td->_d != 0.0))
cast = con; // Replace non-constant val by con.
}
}
break;
case BoolTest::ne:
if (tcon == TypePtr::NULL_PTR) {
cast = cast_not_null(val, false);
}
break;
default:
// (At this point we could record int range types with CastII.)
break;
}
if (ccast != NULL) {
const Type* tcc = ccast->as_Type()->type();
assert(tcc != tval && tcc->higher_equal(tval), "must improve");
// Delay transform() call to allow recovery of pre-cast value
// at the control merge.
ccast->set_req(0, control());
_gvn.set_type_bottom(ccast);
record_for_igvn(ccast);
cast = ccast;
}
if (cast != NULL) { // Here's the payoff.
replace_in_map(val, cast);
}
}
/**
* Use speculative type to optimize CmpP node: if comparison is
* against the low level class, cast the object to the speculative
* type if any. CmpP should then go away.
*
* @param c expected CmpP node
* @return result of CmpP on object casted to speculative type
*
*/
Node* Parse::optimize_cmp_with_klass(Node* c) {
// If this is transformed by the _gvn to a comparison with the low
// level klass then we may be able to use speculation
if (c->Opcode() == Op_CmpP &&
(c->in(1)->Opcode() == Op_LoadKlass || c->in(1)->Opcode() == Op_DecodeNKlass) &&
c->in(2)->is_Con()) {
Node* load_klass = NULL;
Node* decode = NULL;
if (c->in(1)->Opcode() == Op_DecodeNKlass) {
decode = c->in(1);
load_klass = c->in(1)->in(1);
} else {
load_klass = c->in(1);
}
if (load_klass->in(2)->is_AddP()) {
Node* addp = load_klass->in(2);
Node* obj = addp->in(AddPNode::Address);
const TypeOopPtr* obj_type = _gvn.type(obj)->is_oopptr();
if (obj_type->speculative_type_not_null() != NULL) {
ciKlass* k = obj_type->speculative_type();
inc_sp(2);
obj = maybe_cast_profiled_obj(obj, k);
dec_sp(2);
// Make the CmpP use the casted obj
addp = basic_plus_adr(obj, addp->in(AddPNode::Offset));
load_klass = load_klass->clone();
load_klass->set_req(2, addp);
load_klass = _gvn.transform(load_klass);
if (decode != NULL) {
decode = decode->clone();
decode->set_req(1, load_klass);
load_klass = _gvn.transform(decode);
}
c = c->clone();
c->set_req(1, load_klass);
c = _gvn.transform(c);
}
}
}
return c;
}
//------------------------------do_one_bytecode--------------------------------
// Parse this bytecode, and alter the Parsers JVM->Node mapping
void Parse::do_one_bytecode() {
Node *a, *b, *c, *d; // Handy temps
BoolTest::mask btest;
int i;
assert(!has_exceptions(), "bytecode entry state must be clear of throws");
if (C->check_node_count(NodeLimitFudgeFactor * 5,
"out of nodes parsing method")) {
return;
}
#ifdef ASSERT
// for setting breakpoints
if (TraceOptoParse) {
tty->print(" @");
dump_bci(bci());
tty->print(" %s", Bytecodes::name(bc()));
tty->cr();
}
#endif
switch (bc()) {
case Bytecodes::_nop:
// do nothing
break;
case Bytecodes::_lconst_0:
push_pair(longcon(0));
break;
case Bytecodes::_lconst_1:
push_pair(longcon(1));
break;
case Bytecodes::_fconst_0:
push(zerocon(T_FLOAT));
break;
case Bytecodes::_fconst_1:
push(makecon(TypeF::ONE));
break;
case Bytecodes::_fconst_2:
push(makecon(TypeF::make(2.0f)));
break;
case Bytecodes::_dconst_0:
push_pair(zerocon(T_DOUBLE));
break;
case Bytecodes::_dconst_1:
push_pair(makecon(TypeD::ONE));
break;
case Bytecodes::_iconst_m1:push(intcon(-1)); break;
case Bytecodes::_iconst_0: push(intcon( 0)); break;
case Bytecodes::_iconst_1: push(intcon( 1)); break;
case Bytecodes::_iconst_2: push(intcon( 2)); break;
case Bytecodes::_iconst_3: push(intcon( 3)); break;
case Bytecodes::_iconst_4: push(intcon( 4)); break;
case Bytecodes::_iconst_5: push(intcon( 5)); break;
case Bytecodes::_bipush: push(intcon(iter().get_constant_u1())); break;
case Bytecodes::_sipush: push(intcon(iter().get_constant_u2())); break;
case Bytecodes::_aconst_null: push(null()); break;
case Bytecodes::_ldc:
case Bytecodes::_ldc_w:
case Bytecodes::_ldc2_w: {
ciConstant constant = iter().get_constant();
if (constant.is_loaded()) {
const Type* con_type = Type::make_from_constant(constant);
if (con_type != NULL) {
push_node(con_type->basic_type(), makecon(con_type));
}
} else {
// If the constant is unresolved or in error state, run this BC in the interpreter.
if (iter().is_in_error()) {
uncommon_trap(Deoptimization::make_trap_request(Deoptimization::Reason_unhandled,
Deoptimization::Action_none),
NULL, "constant in error state", true /* must_throw */);
} else {
int index = iter().get_constant_pool_index();
uncommon_trap(Deoptimization::make_trap_request(Deoptimization::Reason_unloaded,
Deoptimization::Action_reinterpret,
index),
NULL, "unresolved constant", false /* must_throw */);
}
}
break;
}
case Bytecodes::_aload_0:
push( local(0) );
break;
case Bytecodes::_aload_1:
push( local(1) );
break;
case Bytecodes::_aload_2:
push( local(2) );
break;
case Bytecodes::_aload_3:
push( local(3) );
break;
case Bytecodes::_aload:
push( local(iter().get_index()) );
break;
--> --------------------
--> maximum size reached
--> --------------------
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