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/*
* Copyright (c) 1997, 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 "gc/shared/barrierSet.hpp"
#include "gc/shared/c2/barrierSetC2.hpp"
#include "libadt/vectset.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "opto/ad.hpp"
#include "opto/callGenerator.hpp"
#include "opto/castnode.hpp"
#include "opto/cfgnode.hpp"
#include "opto/connode.hpp"
#include "opto/loopnode.hpp"
#include "opto/machnode.hpp"
#include "opto/matcher.hpp"
#include "opto/node.hpp"
#include "opto/opcodes.hpp"
#include "opto/regmask.hpp"
#include "opto/rootnode.hpp"
#include "opto/type.hpp"
#include "utilities/copy.hpp"
#include "utilities/macros.hpp"
#include "utilities/powerOfTwo.hpp"
#include "utilities/stringUtils.hpp"
class RegMask;
// #include "phase.hpp"
class PhaseTransform;
class PhaseGVN;
// Arena we are currently building Nodes in
const uint Node::NotAMachineReg = 0xffff0000;
#ifndef PRODUCT
extern int nodes_created;
#endif
#ifdef __clang__
#pragma clang diagnostic push
#pragma GCC diagnostic ignored "-Wuninitialized"
#endif
#ifdef ASSERT
//-------------------------- construct_node------------------------------------
// Set a breakpoint here to identify where a particular node index is built.
void Node::verify_construction() {
_debug_orig = NULL;
int old_debug_idx = Compile::debug_idx();
int new_debug_idx = old_debug_idx + 1;
if (new_debug_idx > 0) {
// Arrange that the lowest five decimal digits of _debug_idx
// will repeat those of _idx. In case this is somehow pathological,
// we continue to assign negative numbers (!) consecutively.
const int mod = 100000;
int bump = (int)(_idx - new_debug_idx) % mod;
if (bump < 0) {
bump += mod;
}
assert(bump >= 0 && bump < mod, "");
new_debug_idx += bump;
}
Compile::set_debug_idx(new_debug_idx);
set_debug_idx(new_debug_idx);
Compile* C = Compile::current();
assert(C->unique() < (INT_MAX - 1), "Node limit exceeded INT_MAX");
if (!C->phase_optimize_finished()) {
// Only check assert during parsing and optimization phase. Skip it while generating code.
assert(C->live_nodes() <= C->max_node_limit(), "Live Node limit exceeded limit");
}
if (BreakAtNode != 0 && (_debug_idx == BreakAtNode || (int)_idx == BreakAtNode)) {
tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d", _idx, _debug_idx);
BREAKPOINT;
}
#if OPTO_DU_ITERATOR_ASSERT
_last_del = NULL;
_del_tick = 0;
#endif
_hash_lock = 0;
}
// #ifdef ASSERT ...
#if OPTO_DU_ITERATOR_ASSERT
void DUIterator_Common::sample(const Node* node) {
_vdui = VerifyDUIterators;
_node = node;
_outcnt = node->_outcnt;
_del_tick = node->_del_tick;
_last = NULL;
}
void DUIterator_Common::verify(const Node* node, bool at_end_ok) {
assert(_node == node, "consistent iterator source");
assert(_del_tick == node->_del_tick, "no unexpected deletions allowed");
}
void DUIterator_Common::verify_resync() {
// Ensure that the loop body has just deleted the last guy produced.
const Node* node = _node;
// Ensure that at least one copy of the last-seen edge was deleted.
// Note: It is OK to delete multiple copies of the last-seen edge.
// Unfortunately, we have no way to verify that all the deletions delete
// that same edge. On this point we must use the Honor System.
assert(node->_del_tick >= _del_tick+1, "must have deleted an edge");
assert(node->_last_del == _last, "must have deleted the edge just produced");
// We liked this deletion, so accept the resulting outcnt and tick.
_outcnt = node->_outcnt;
_del_tick = node->_del_tick;
}
void DUIterator_Common::reset(const DUIterator_Common& that) {
if (this == &that) return; // ignore assignment to self
if (!_vdui) {
// We need to initialize everything, overwriting garbage values.
_last = that._last;
_vdui = that._vdui;
}
// Note: It is legal (though odd) for an iterator over some node x
// to be reassigned to iterate over another node y. Some doubly-nested
// progress loops depend on being able to do this.
const Node* node = that._node;
// Re-initialize everything, except _last.
_node = node;
_outcnt = node->_outcnt;
_del_tick = node->_del_tick;
}
void DUIterator::sample(const Node* node) {
DUIterator_Common::sample(node); // Initialize the assertion data.
_refresh_tick = 0; // No refreshes have happened, as yet.
}
void DUIterator::verify(const Node* node, bool at_end_ok) {
DUIterator_Common::verify(node, at_end_ok);
assert(_idx < node->_outcnt + (uint)at_end_ok, "idx in range");
}
void DUIterator::verify_increment() {
if (_refresh_tick & 1) {
// We have refreshed the index during this loop.
// Fix up _idx to meet asserts.
if (_idx > _outcnt) _idx = _outcnt;
}
verify(_node, true);
}
void DUIterator::verify_resync() {
// Note: We do not assert on _outcnt, because insertions are OK here.
DUIterator_Common::verify_resync();
// Make sure we are still in sync, possibly with no more out-edges:
verify(_node, true);
}
void DUIterator::reset(const DUIterator& that) {
if (this == &that) return; // self assignment is always a no-op
assert(that._refresh_tick == 0, "assign only the result of Node::outs()");
assert(that._idx == 0, "assign only the result of Node::outs()");
assert(_idx == that._idx, "already assigned _idx");
if (!_vdui) {
// We need to initialize everything, overwriting garbage values.
sample(that._node);
} else {
DUIterator_Common::reset(that);
if (_refresh_tick & 1) {
_refresh_tick++; // Clear the "was refreshed" flag.
}
assert(_refresh_tick < 2*100000, "DU iteration must converge quickly");
}
}
void DUIterator::refresh() {
DUIterator_Common::sample(_node); // Re-fetch assertion data.
_refresh_tick |= 1; // Set the "was refreshed" flag.
}
void DUIterator::verify_finish() {
// If the loop has killed the node, do not require it to re-run.
if (_node->_outcnt == 0) _refresh_tick &= ~1;
// If this assert triggers, it means that a loop used refresh_out_pos
// to re-synch an iteration index, but the loop did not correctly
// re-run itself, using a "while (progress)" construct.
// This iterator enforces the rule that you must keep trying the loop
// until it "runs clean" without any need for refreshing.
assert(!(_refresh_tick & 1), "the loop must run once with no refreshing");
}
void DUIterator_Fast::verify(const Node* node, bool at_end_ok) {
DUIterator_Common::verify(node, at_end_ok);
Node** out = node->_out;
uint cnt = node->_outcnt;
assert(cnt == _outcnt, "no insertions allowed");
assert(_outp >= out && _outp <= out + cnt - !at_end_ok, "outp in range");
// This last check is carefully designed to work for NO_OUT_ARRAY.
}
void DUIterator_Fast::verify_limit() {
const Node* node = _node;
verify(node, true);
assert(_outp == node->_out + node->_outcnt, "limit still correct");
}
void DUIterator_Fast::verify_resync() {
const Node* node = _node;
if (_outp == node->_out + _outcnt) {
// Note that the limit imax, not the pointer i, gets updated with the
// exact count of deletions. (For the pointer it's always "--i".)
assert(node->_outcnt+node->_del_tick == _outcnt+_del_tick, "no insertions allowed with deletion(s)");
// This is a limit pointer, with a name like "imax".
// Fudge the _last field so that the common assert will be happy.
_last = (Node*) node->_last_del;
DUIterator_Common::verify_resync();
} else {
assert(node->_outcnt < _outcnt, "no insertions allowed with deletion(s)");
// A normal internal pointer.
DUIterator_Common::verify_resync();
// Make sure we are still in sync, possibly with no more out-edges:
verify(node, true);
}
}
void DUIterator_Fast::verify_relimit(uint n) {
const Node* node = _node;
assert((int)n > 0, "use imax -= n only with a positive count");
// This must be a limit pointer, with a name like "imax".
assert(_outp == node->_out + node->_outcnt, "apply -= only to a limit (imax)");
// The reported number of deletions must match what the node saw.
assert(node->_del_tick == _del_tick + n, "must have deleted n edges");
// Fudge the _last field so that the common assert will be happy.
_last = (Node*) node->_last_del;
DUIterator_Common::verify_resync();
}
void DUIterator_Fast::reset(const DUIterator_Fast& that) {
assert(_outp == that._outp, "already assigned _outp");
DUIterator_Common::reset(that);
}
void DUIterator_Last::verify(const Node* node, bool at_end_ok) {
// at_end_ok means the _outp is allowed to underflow by 1
_outp += at_end_ok;
DUIterator_Fast::verify(node, at_end_ok); // check _del_tick, etc.
_outp -= at_end_ok;
assert(_outp == (node->_out + node->_outcnt) - 1, "pointer must point to end of nodes");
}
void DUIterator_Last::verify_limit() {
// Do not require the limit address to be resynched.
//verify(node, true);
assert(_outp == _node->_out, "limit still correct");
}
void DUIterator_Last::verify_step(uint num_edges) {
assert((int)num_edges > 0, "need non-zero edge count for loop progress");
_outcnt -= num_edges;
_del_tick += num_edges;
// Make sure we are still in sync, possibly with no more out-edges:
const Node* node = _node;
verify(node, true);
assert(node->_last_del == _last, "must have deleted the edge just produced");
}
#endif //OPTO_DU_ITERATOR_ASSERT
#endif //ASSERT
// This constant used to initialize _out may be any non-null value.
// The value NULL is reserved for the top node only.
#define NO_OUT_ARRAY ((Node**)-1)
// Out-of-line code from node constructors.
// Executed only when extra debug info. is being passed around.
static void init_node_notes(Compile* C, int idx, Node_Notes* nn) {
C->set_node_notes_at(idx, nn);
}
// Shared initialization code.
inline int Node::Init(int req) {
Compile* C = Compile::current();
int idx = C->next_unique();
NOT_PRODUCT(_igv_idx = C->next_igv_idx());
// Allocate memory for the necessary number of edges.
if (req > 0) {
// Allocate space for _in array to have double alignment.
_in = (Node **) ((char *) (C->node_arena()->AmallocWords(req * sizeof(void*))));
}
// If there are default notes floating around, capture them:
Node_Notes* nn = C->default_node_notes();
if (nn != NULL) init_node_notes(C, idx, nn);
// Note: At this point, C is dead,
// and we begin to initialize the new Node.
_cnt = _max = req;
_outcnt = _outmax = 0;
_class_id = Class_Node;
_flags = 0;
_out = NO_OUT_ARRAY;
return idx;
}
//------------------------------Node-------------------------------------------
// Create a Node, with a given number of required edges.
Node::Node(uint req)
: _idx(Init(req))
#ifdef ASSERT
, _parse_idx(_idx)
#endif
{
assert( req < Compile::current()->max_node_limit() - NodeLimitFudgeFactor, "Input limit exceeded" );
debug_only( verify_construction() );
NOT_PRODUCT(nodes_created++);
if (req == 0) {
_in = NULL;
} else {
Node** to = _in;
for(uint i = 0; i < req; i++) {
to[i] = NULL;
}
}
}
//------------------------------Node-------------------------------------------
Node::Node(Node *n0)
: _idx(Init(1))
#ifdef ASSERT
, _parse_idx(_idx)
#endif
{
debug_only( verify_construction() );
NOT_PRODUCT(nodes_created++);
assert( is_not_dead(n0), "can not use dead node");
_in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
}
//------------------------------Node-------------------------------------------
Node::Node(Node *n0, Node *n1)
: _idx(Init(2))
#ifdef ASSERT
, _parse_idx(_idx)
#endif
{
debug_only( verify_construction() );
NOT_PRODUCT(nodes_created++);
assert( is_not_dead(n0), "can not use dead node");
assert( is_not_dead(n1), "can not use dead node");
_in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
_in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
}
//------------------------------Node-------------------------------------------
Node::Node(Node *n0, Node *n1, Node *n2)
: _idx(Init(3))
#ifdef ASSERT
, _parse_idx(_idx)
#endif
{
debug_only( verify_construction() );
NOT_PRODUCT(nodes_created++);
assert( is_not_dead(n0), "can not use dead node");
assert( is_not_dead(n1), "can not use dead node");
assert( is_not_dead(n2), "can not use dead node");
_in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
_in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
_in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
}
//------------------------------Node-------------------------------------------
Node::Node(Node *n0, Node *n1, Node *n2, Node *n3)
: _idx(Init(4))
#ifdef ASSERT
, _parse_idx(_idx)
#endif
{
debug_only( verify_construction() );
NOT_PRODUCT(nodes_created++);
assert( is_not_dead(n0), "can not use dead node");
assert( is_not_dead(n1), "can not use dead node");
assert( is_not_dead(n2), "can not use dead node");
assert( is_not_dead(n3), "can not use dead node");
_in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
_in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
_in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
_in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
}
//------------------------------Node-------------------------------------------
Node::Node(Node *n0, Node *n1, Node *n2, Node *n3, Node *n4)
: _idx(Init(5))
#ifdef ASSERT
, _parse_idx(_idx)
#endif
{
debug_only( verify_construction() );
NOT_PRODUCT(nodes_created++);
assert( is_not_dead(n0), "can not use dead node");
assert( is_not_dead(n1), "can not use dead node");
assert( is_not_dead(n2), "can not use dead node");
assert( is_not_dead(n3), "can not use dead node");
assert( is_not_dead(n4), "can not use dead node");
_in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
_in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
_in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
_in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
_in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
}
//------------------------------Node-------------------------------------------
Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
Node *n4, Node *n5)
: _idx(Init(6))
#ifdef ASSERT
, _parse_idx(_idx)
#endif
{
debug_only( verify_construction() );
NOT_PRODUCT(nodes_created++);
assert( is_not_dead(n0), "can not use dead node");
assert( is_not_dead(n1), "can not use dead node");
assert( is_not_dead(n2), "can not use dead node");
assert( is_not_dead(n3), "can not use dead node");
assert( is_not_dead(n4), "can not use dead node");
assert( is_not_dead(n5), "can not use dead node");
_in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
_in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
_in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
_in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
_in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
_in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
}
//------------------------------Node-------------------------------------------
Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
Node *n4, Node *n5, Node *n6)
: _idx(Init(7))
#ifdef ASSERT
, _parse_idx(_idx)
#endif
{
debug_only( verify_construction() );
NOT_PRODUCT(nodes_created++);
assert( is_not_dead(n0), "can not use dead node");
assert( is_not_dead(n1), "can not use dead node");
assert( is_not_dead(n2), "can not use dead node");
assert( is_not_dead(n3), "can not use dead node");
assert( is_not_dead(n4), "can not use dead node");
assert( is_not_dead(n5), "can not use dead node");
assert( is_not_dead(n6), "can not use dead node");
_in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
_in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
_in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
_in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
_in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
_in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
_in[6] = n6; if (n6 != NULL) n6->add_out((Node *)this);
}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
//------------------------------clone------------------------------------------
// Clone a Node.
Node *Node::clone() const {
Compile* C = Compile::current();
uint s = size_of(); // Size of inherited Node
Node *n = (Node*)C->node_arena()->AmallocWords(size_of() + _max*sizeof(Node*));
Copy::conjoint_words_to_lower((HeapWord*)this, (HeapWord*)n, s);
// Set the new input pointer array
n->_in = (Node**)(((char*)n)+s);
// Cannot share the old output pointer array, so kill it
n->_out = NO_OUT_ARRAY;
// And reset the counters to 0
n->_outcnt = 0;
n->_outmax = 0;
// Unlock this guy, since he is not in any hash table.
debug_only(n->_hash_lock = 0);
// Walk the old node's input list to duplicate its edges
uint i;
for( i = 0; i < len(); i++ ) {
Node *x = in(i);
n->_in[i] = x;
if (x != NULL) x->add_out(n);
}
if (is_macro()) {
C->add_macro_node(n);
}
if (is_expensive()) {
C->add_expensive_node(n);
}
if (for_post_loop_opts_igvn()) {
// Don't add cloned node to Compile::_for_post_loop_opts_igvn list automatically.
// If it is applicable, it will happen anyway when the cloned node is registered with IGVN.
n->remove_flag(Node::NodeFlags::Flag_for_post_loop_opts_igvn);
}
if (n->is_reduction()) {
// Do not copy reduction information. This must be explicitly set by the calling code.
n->remove_flag(Node::Flag_is_reduction);
}
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
bs->register_potential_barrier_node(n);
n->set_idx(C->next_unique()); // Get new unique index as well
NOT_PRODUCT(n->_igv_idx = C->next_igv_idx());
debug_only( n->verify_construction() );
NOT_PRODUCT(nodes_created++);
// Do not patch over the debug_idx of a clone, because it makes it
// impossible to break on the clone's moment of creation.
//debug_only( n->set_debug_idx( debug_idx() ) );
C->copy_node_notes_to(n, (Node*) this);
// MachNode clone
uint nopnds;
if (this->is_Mach() && (nopnds = this->as_Mach()->num_opnds()) > 0) {
MachNode *mach = n->as_Mach();
MachNode *mthis = this->as_Mach();
// Get address of _opnd_array.
// It should be the same offset since it is the clone of this node.
MachOper **from = mthis->_opnds;
MachOper **to = (MachOper **)((size_t)(&mach->_opnds) +
pointer_delta((const void*)from,
(const void*)(&mthis->_opnds), 1));
mach->_opnds = to;
for ( uint i = 0; i < nopnds; ++i ) {
to[i] = from[i]->clone();
}
}
if (n->is_Call()) {
// CallGenerator is linked to the original node.
CallGenerator* cg = n->as_Call()->generator();
if (cg != NULL) {
CallGenerator* cloned_cg = cg->with_call_node(n->as_Call());
n->as_Call()->set_generator(cloned_cg);
C->print_inlining_assert_ready();
C->print_inlining_move_to(cg);
C->print_inlining_update(cloned_cg);
}
}
if (n->is_SafePoint()) {
// Scalar replacement and macro expansion might modify the JVMState.
// Clone it to make sure it's not shared between SafePointNodes.
n->as_SafePoint()->clone_jvms(C);
n->as_SafePoint()->clone_replaced_nodes();
}
Compile::current()->record_modified_node(n);
return n; // Return the clone
}
//---------------------------setup_is_top--------------------------------------
// Call this when changing the top node, to reassert the invariants
// required by Node::is_top. See Compile::set_cached_top_node.
void Node::setup_is_top() {
if (this == (Node*)Compile::current()->top()) {
// This node has just become top. Kill its out array.
_outcnt = _outmax = 0;
_out = NULL; // marker value for top
assert(is_top(), "must be top");
} else {
if (_out == NULL) _out = NO_OUT_ARRAY;
assert(!is_top(), "must not be top");
}
}
//------------------------------~Node------------------------------------------
// Fancy destructor; eagerly attempt to reclaim Node numberings and storage
void Node::destruct(PhaseValues* phase) {
Compile* compile = (phase != NULL) ? phase->C : Compile::current();
if (phase != NULL && phase->is_IterGVN()) {
phase->is_IterGVN()->_worklist.remove(this);
}
// If this is the most recently created node, reclaim its index. Otherwise,
// record the node as dead to keep liveness information accurate.
if ((uint)_idx+1 == compile->unique()) {
compile->set_unique(compile->unique()-1);
} else {
compile->record_dead_node(_idx);
}
// Clear debug info:
Node_Notes* nn = compile->node_notes_at(_idx);
if (nn != NULL) nn->clear();
// Walk the input array, freeing the corresponding output edges
_cnt = _max; // forget req/prec distinction
uint i;
for( i = 0; i < _max; i++ ) {
set_req(i, NULL);
//assert(def->out(def->outcnt()-1) == (Node *)this,"bad def-use hacking in reclaim");
}
assert(outcnt() == 0, "deleting a node must not leave a dangling use");
// See if the input array was allocated just prior to the object
int edge_size = _max*sizeof(void*);
int out_edge_size = _outmax*sizeof(void*);
char *edge_end = ((char*)_in) + edge_size;
char *out_array = (char*)(_out == NO_OUT_ARRAY? NULL: _out);
int node_size = size_of();
// Free the output edge array
if (out_edge_size > 0) {
compile->node_arena()->Afree(out_array, out_edge_size);
}
// Free the input edge array and the node itself
if( edge_end == (char*)this ) {
// It was; free the input array and object all in one hit
#ifndef ASSERT
compile->node_arena()->Afree(_in,edge_size+node_size);
#endif
} else {
// Free just the input array
compile->node_arena()->Afree(_in,edge_size);
// Free just the object
#ifndef ASSERT
compile->node_arena()->Afree(this,node_size);
#endif
}
if (is_macro()) {
compile->remove_macro_node(this);
}
if (is_expensive()) {
compile->remove_expensive_node(this);
}
if (Opcode() == Op_Opaque4) {
compile->remove_skeleton_predicate_opaq(this);
}
if (for_post_loop_opts_igvn()) {
compile->remove_from_post_loop_opts_igvn(this);
}
if (is_SafePoint()) {
as_SafePoint()->delete_replaced_nodes();
if (is_CallStaticJava()) {
compile->remove_unstable_if_trap(as_CallStaticJava(), false);
}
}
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
bs->unregister_potential_barrier_node(this);
#ifdef ASSERT
// We will not actually delete the storage, but we'll make the node unusable.
*(address*)this = badAddress; // smash the C++ vtbl, probably
_in = _out = (Node**) badAddress;
_max = _cnt = _outmax = _outcnt = 0;
compile->remove_modified_node(this);
#endif
}
//------------------------------grow-------------------------------------------
// Grow the input array, making space for more edges
void Node::grow(uint len) {
Arena* arena = Compile::current()->node_arena();
uint new_max = _max;
if( new_max == 0 ) {
_max = 4;
_in = (Node**)arena->Amalloc(4*sizeof(Node*));
Node** to = _in;
to[0] = NULL;
to[1] = NULL;
to[2] = NULL;
to[3] = NULL;
return;
}
new_max = next_power_of_2(len);
// Trimming to limit allows a uint8 to handle up to 255 edges.
// Previously I was using only powers-of-2 which peaked at 128 edges.
//if( new_max >= limit ) new_max = limit-1;
_in = (Node**)arena->Arealloc(_in, _max*sizeof(Node*), new_max*sizeof(Node*));
Copy::zero_to_bytes(&_in[_max], (new_max-_max)*sizeof(Node*)); // NULL all new space
_max = new_max; // Record new max length
// This assertion makes sure that Node::_max is wide enough to
// represent the numerical value of new_max.
assert(_max == new_max && _max > len, "int width of _max is too small");
}
//-----------------------------out_grow----------------------------------------
// Grow the input array, making space for more edges
void Node::out_grow( uint len ) {
assert(!is_top(), "cannot grow a top node's out array");
Arena* arena = Compile::current()->node_arena();
uint new_max = _outmax;
if( new_max == 0 ) {
_outmax = 4;
_out = (Node **)arena->Amalloc(4*sizeof(Node*));
return;
}
new_max = next_power_of_2(len);
// Trimming to limit allows a uint8 to handle up to 255 edges.
// Previously I was using only powers-of-2 which peaked at 128 edges.
//if( new_max >= limit ) new_max = limit-1;
assert(_out != NULL && _out != NO_OUT_ARRAY, "out must have sensible value");
_out = (Node**)arena->Arealloc(_out,_outmax*sizeof(Node*),new_max*sizeof(Node*));
//Copy::zero_to_bytes(&_out[_outmax], (new_max-_outmax)*sizeof(Node*)); // NULL all new space
_outmax = new_max; // Record new max length
// This assertion makes sure that Node::_max is wide enough to
// represent the numerical value of new_max.
assert(_outmax == new_max && _outmax > len, "int width of _outmax is too small");
}
#ifdef ASSERT
//------------------------------is_dead----------------------------------------
bool Node::is_dead() const {
// Mach and pinch point nodes may look like dead.
if( is_top() || is_Mach() || (Opcode() == Op_Node && _outcnt > 0) )
return false;
for( uint i = 0; i < _max; i++ )
if( _in[i] != NULL )
return false;
dump();
return true;
}
bool Node::is_reachable_from_root() const {
ResourceMark rm;
Unique_Node_List wq;
wq.push((Node*)this);
RootNode* root = Compile::current()->root();
for (uint i = 0; i < wq.size(); i++) {
Node* m = wq.at(i);
if (m == root) {
return true;
}
for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
Node* u = m->fast_out(j);
wq.push(u);
}
}
return false;
}
#endif
//------------------------------is_unreachable---------------------------------
bool Node::is_unreachable(PhaseIterGVN &igvn) const {
assert(!is_Mach(), "doesn't work with MachNodes");
return outcnt() == 0 || igvn.type(this) == Type::TOP || (in(0) != NULL && in(0)->is_top());
}
//------------------------------add_req----------------------------------------
// Add a new required input at the end
void Node::add_req( Node *n ) {
assert( is_not_dead(n), "can not use dead node");
// Look to see if I can move precedence down one without reallocating
if( (_cnt >= _max) || (in(_max-1) != NULL) )
grow( _max+1 );
// Find a precedence edge to move
if( in(_cnt) != NULL ) { // Next precedence edge is busy?
uint i;
for( i=_cnt; i<_max; i++ )
if( in(i) == NULL ) // Find the NULL at end of prec edge list
break; // There must be one, since we grew the array
_in[i] = in(_cnt); // Move prec over, making space for req edge
}
_in[_cnt++] = n; // Stuff over old prec edge
if (n != NULL) n->add_out((Node *)this);
Compile::current()->record_modified_node(this);
}
//---------------------------add_req_batch-------------------------------------
// Add a new required input at the end
void Node::add_req_batch( Node *n, uint m ) {
assert( is_not_dead(n), "can not use dead node");
// check various edge cases
if ((int)m <= 1) {
assert((int)m >= 0, "oob");
if (m != 0) add_req(n);
return;
}
// Look to see if I can move precedence down one without reallocating
if( (_cnt+m) > _max || _in[_max-m] )
grow( _max+m );
// Find a precedence edge to move
if( _in[_cnt] != NULL ) { // Next precedence edge is busy?
uint i;
for( i=_cnt; i<_max; i++ )
if( _in[i] == NULL ) // Find the NULL at end of prec edge list
break; // There must be one, since we grew the array
// Slide all the precs over by m positions (assume #prec << m).
Copy::conjoint_words_to_higher((HeapWord*)&_in[_cnt], (HeapWord*)&_in[_cnt+m], ((i-_cnt)*sizeof(Node*)));
}
// Stuff over the old prec edges
for(uint i=0; i<m; i++ ) {
_in[_cnt++] = n;
}
// Insert multiple out edges on the node.
if (n != NULL && !n->is_top()) {
for(uint i=0; i<m; i++ ) {
n->add_out((Node *)this);
}
}
Compile::current()->record_modified_node(this);
}
//------------------------------del_req----------------------------------------
// Delete the required edge and compact the edge array
void Node::del_req( uint idx ) {
assert( idx < _cnt, "oob");
assert( !VerifyHashTableKeys || _hash_lock == 0,
"remove node from hash table before modifying it");
// First remove corresponding def-use edge
Node *n = in(idx);
if (n != NULL) n->del_out((Node *)this);
_in[idx] = in(--_cnt); // Compact the array
// Avoid spec violation: Gap in prec edges.
close_prec_gap_at(_cnt);
Compile::current()->record_modified_node(this);
}
//------------------------------del_req_ordered--------------------------------
// Delete the required edge and compact the edge array with preserved order
void Node::del_req_ordered( uint idx ) {
assert( idx < _cnt, "oob");
assert( !VerifyHashTableKeys || _hash_lock == 0,
"remove node from hash table before modifying it");
// First remove corresponding def-use edge
Node *n = in(idx);
if (n != NULL) n->del_out((Node *)this);
if (idx < --_cnt) { // Not last edge ?
Copy::conjoint_words_to_lower((HeapWord*)&_in[idx+1], (HeapWord*)&_in[idx], ((_cnt-idx)*sizeof(Node*)));
}
// Avoid spec violation: Gap in prec edges.
close_prec_gap_at(_cnt);
Compile::current()->record_modified_node(this);
}
//------------------------------ins_req----------------------------------------
// Insert a new required input at the end
void Node::ins_req( uint idx, Node *n ) {
assert( is_not_dead(n), "can not use dead node");
add_req(NULL); // Make space
assert( idx < _max, "Must have allocated enough space");
// Slide over
if(_cnt-idx-1 > 0) {
Copy::conjoint_words_to_higher((HeapWord*)&_in[idx], (HeapWord*)&_in[idx+1], ((_cnt-idx-1)*sizeof(Node*)));
}
_in[idx] = n; // Stuff over old required edge
if (n != NULL) n->add_out((Node *)this); // Add reciprocal def-use edge
Compile::current()->record_modified_node(this);
}
//-----------------------------find_edge---------------------------------------
int Node::find_edge(Node* n) {
for (uint i = 0; i < len(); i++) {
if (_in[i] == n) return i;
}
return -1;
}
//----------------------------replace_edge-------------------------------------
int Node::replace_edge(Node* old, Node* neww, PhaseGVN* gvn) {
if (old == neww) return 0; // nothing to do
uint nrep = 0;
for (uint i = 0; i < len(); i++) {
if (in(i) == old) {
if (i < req()) {
if (gvn != NULL) {
set_req_X(i, neww, gvn);
} else {
set_req(i, neww);
}
} else {
assert(gvn == NULL || gvn->is_IterGVN() == NULL, "no support for igvn here");
assert(find_prec_edge(neww) == -1, "spec violation: duplicated prec edge (node %d -> %d)", _idx, neww->_idx);
set_prec(i, neww);
}
nrep++;
}
}
return nrep;
}
/**
* Replace input edges in the range pointing to 'old' node.
*/
int Node::replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn) {
if (old == neww) return 0; // nothing to do
uint nrep = 0;
for (int i = start; i < end; i++) {
if (in(i) == old) {
set_req_X(i, neww, gvn);
nrep++;
}
}
return nrep;
}
//-------------------------disconnect_inputs-----------------------------------
// NULL out all inputs to eliminate incoming Def-Use edges.
void Node::disconnect_inputs(Compile* C) {
// the layout of Node::_in
// r: a required input, null is allowed
// p: a precedence, null values are all at the end
// -----------------------------------
// |r|...|r|p|...|p|null|...|null|
// | |
// req() len()
// -----------------------------------
for (uint i = 0; i < req(); ++i) {
if (in(i) != nullptr) {
set_req(i, nullptr);
}
}
// Remove precedence edges if any exist
// Note: Safepoints may have precedence edges, even during parsing
for (uint i = len(); i > req(); ) {
rm_prec(--i); // no-op if _in[i] is nullptr
}
#ifdef ASSERT
// sanity check
for (uint i = 0; i < len(); ++i) {
assert(_in[i] == nullptr, "disconnect_inputs() failed!");
}
#endif
// Node::destruct requires all out edges be deleted first
// debug_only(destruct();) // no reuse benefit expected
C->record_dead_node(_idx);
}
//-----------------------------uncast---------------------------------------
// %%% Temporary, until we sort out CheckCastPP vs. CastPP.
// Strip away casting. (It is depth-limited.)
// Optionally, keep casts with dependencies.
Node* Node::uncast(bool keep_deps) const {
// Should be inline:
//return is_ConstraintCast() ? uncast_helper(this) : (Node*) this;
if (is_ConstraintCast()) {
return uncast_helper(this, keep_deps);
} else {
return (Node*) this;
}
}
// Find out of current node that matches opcode.
Node* Node::find_out_with(int opcode) {
for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
Node* use = fast_out(i);
if (use->Opcode() == opcode) {
return use;
}
}
return NULL;
}
// Return true if the current node has an out that matches opcode.
bool Node::has_out_with(int opcode) {
return (find_out_with(opcode) != NULL);
}
// Return true if the current node has an out that matches any of the opcodes.
bool Node::has_out_with(int opcode1, int opcode2, int opcode3, int opcode4) {
for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
int opcode = fast_out(i)->Opcode();
if (opcode == opcode1 || opcode == opcode2 || opcode == opcode3 || opcode == opcode4) {
return true;
}
}
return false;
}
//---------------------------uncast_helper-------------------------------------
Node* Node::uncast_helper(const Node* p, bool keep_deps) {
#ifdef ASSERT
uint depth_count = 0;
const Node* orig_p = p;
#endif
while (true) {
#ifdef ASSERT
if (depth_count >= K) {
orig_p->dump(4);
if (p != orig_p)
p->dump(1);
}
assert(depth_count++ < K, "infinite loop in Node::uncast_helper");
#endif
if (p == NULL || p->req() != 2) {
break;
} else if (p->is_ConstraintCast()) {
if (keep_deps && p->as_ConstraintCast()->carry_dependency()) {
break; // stop at casts with dependencies
}
p = p->in(1);
} else {
break;
}
}
return (Node*) p;
}
//------------------------------add_prec---------------------------------------
// Add a new precedence input. Precedence inputs are unordered, with
// duplicates removed and NULLs packed down at the end.
void Node::add_prec( Node *n ) {
assert( is_not_dead(n), "can not use dead node");
// Check for NULL at end
if( _cnt >= _max || in(_max-1) )
grow( _max+1 );
// Find a precedence edge to move
uint i = _cnt;
while( in(i) != NULL ) {
if (in(i) == n) return; // Avoid spec violation: duplicated prec edge.
i++;
}
_in[i] = n; // Stuff prec edge over NULL
if ( n != NULL) n->add_out((Node *)this); // Add mirror edge
#ifdef ASSERT
while ((++i)<_max) { assert(_in[i] == NULL, "spec violation: Gap in prec edges (node %d)", _idx); }
#endif
Compile::current()->record_modified_node(this);
}
//------------------------------rm_prec----------------------------------------
// Remove a precedence input. Precedence inputs are unordered, with
// duplicates removed and NULLs packed down at the end.
void Node::rm_prec( uint j ) {
assert(j < _max, "oob: i=%d, _max=%d", j, _max);
assert(j >= _cnt, "not a precedence edge");
if (_in[j] == NULL) return; // Avoid spec violation: Gap in prec edges.
_in[j]->del_out((Node *)this);
close_prec_gap_at(j);
Compile::current()->record_modified_node(this);
}
//------------------------------size_of----------------------------------------
uint Node::size_of() const { return sizeof(*this); }
//------------------------------ideal_reg--------------------------------------
uint Node::ideal_reg() const { return 0; }
//------------------------------jvms-------------------------------------------
JVMState* Node::jvms() const { return NULL; }
#ifdef ASSERT
//------------------------------jvms-------------------------------------------
bool Node::verify_jvms(const JVMState* using_jvms) const {
for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
if (jvms == using_jvms) return true;
}
return false;
}
//------------------------------init_NodeProperty------------------------------
void Node::init_NodeProperty() {
assert(_max_classes <= max_juint, "too many NodeProperty classes");
assert(max_flags() <= max_juint, "too many NodeProperty flags");
}
//-----------------------------max_flags---------------------------------------
juint Node::max_flags() {
return (PD::_last_flag << 1) - 1; // allow flags combination
}
#endif
//------------------------------format-----------------------------------------
// Print as assembly
void Node::format( PhaseRegAlloc *, outputStream *st ) const {}
//------------------------------emit-------------------------------------------
// Emit bytes starting at parameter 'ptr'.
void Node::emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const {}
//------------------------------size-------------------------------------------
// Size of instruction in bytes
uint Node::size(PhaseRegAlloc *ra_) const { return 0; }
//------------------------------CFG Construction-------------------------------
// Nodes that end basic blocks, e.g. IfTrue/IfFalse, JumpProjNode, Root,
// Goto and Return.
const Node *Node::is_block_proj() const { return 0; }
// Minimum guaranteed type
const Type *Node::bottom_type() const { return Type::BOTTOM; }
//------------------------------raise_bottom_type------------------------------
// Get the worst-case Type output for this Node.
void Node::raise_bottom_type(const Type* new_type) {
if (is_Type()) {
TypeNode *n = this->as_Type();
if (VerifyAliases) {
assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
}
n->set_type(new_type);
} else if (is_Load()) {
LoadNode *n = this->as_Load();
if (VerifyAliases) {
assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
}
n->set_type(new_type);
}
}
//------------------------------Identity---------------------------------------
// Return a node that the given node is equivalent to.
Node* Node::Identity(PhaseGVN* phase) {
return this; // Default to no identities
}
//------------------------------Value------------------------------------------
// Compute a new Type for a node using the Type of the inputs.
const Type* Node::Value(PhaseGVN* phase) const {
return bottom_type(); // Default to worst-case Type
}
//------------------------------Ideal------------------------------------------
//
// 'Idealize' the graph rooted at this Node.
//
// In order to be efficient and flexible there are some subtle invariants
// these Ideal calls need to hold. Running with '+VerifyIterativeGVN' checks
// these invariants, although its too slow to have on by default. If you are
// hacking an Ideal call, be sure to test with +VerifyIterativeGVN!
//
// The Ideal call almost arbitrarily reshape the graph rooted at the 'this'
// pointer. If ANY change is made, it must return the root of the reshaped
// graph - even if the root is the same Node. Example: swapping the inputs
// to an AddINode gives the same answer and same root, but you still have to
// return the 'this' pointer instead of NULL.
//
// You cannot return an OLD Node, except for the 'this' pointer. Use the
// Identity call to return an old Node; basically if Identity can find
// another Node have the Ideal call make no change and return NULL.
// Example: AddINode::Ideal must check for add of zero; in this case it
// returns NULL instead of doing any graph reshaping.
//
// You cannot modify any old Nodes except for the 'this' pointer. Due to
// sharing there may be other users of the old Nodes relying on their current
// semantics. Modifying them will break the other users.
// Example: when reshape "(X+3)+4" into "X+7" you must leave the Node for
// "X+3" unchanged in case it is shared.
//
// If you modify the 'this' pointer's inputs, you should use
// 'set_req'. If you are making a new Node (either as the new root or
// some new internal piece) you may use 'init_req' to set the initial
// value. You can make a new Node with either 'new' or 'clone'. In
// either case, def-use info is correctly maintained.
//
// Example: reshape "(X+3)+4" into "X+7":
// set_req(1, in(1)->in(1));
// set_req(2, phase->intcon(7));
// return this;
// Example: reshape "X*4" into "X<<2"
// return new LShiftINode(in(1), phase->intcon(2));
//
// You must call 'phase->transform(X)' on any new Nodes X you make, except
// for the returned root node. Example: reshape "X*31" with "(X<<5)-X".
// Node *shift=phase->transform(new LShiftINode(in(1),phase->intcon(5)));
// return new AddINode(shift, in(1));
//
// When making a Node for a constant use 'phase->makecon' or 'phase->intcon'.
// These forms are faster than 'phase->transform(new ConNode())' and Do
// The Right Thing with def-use info.
//
// You cannot bury the 'this' Node inside of a graph reshape. If the reshaped
// graph uses the 'this' Node it must be the root. If you want a Node with
// the same Opcode as the 'this' pointer use 'clone'.
//
Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
return NULL; // Default to being Ideal already
}
// Some nodes have specific Ideal subgraph transformations only if they are
// unique users of specific nodes. Such nodes should be put on IGVN worklist
// for the transformations to happen.
bool Node::has_special_unique_user() const {
assert(outcnt() == 1, "match only for unique out");
Node* n = unique_out();
int op = Opcode();
if (this->is_Store()) {
// Condition for back-to-back stores folding.
return n->Opcode() == op && n->in(MemNode::Memory) == this;
} else if (this->is_Load() || this->is_DecodeN() || this->is_Phi()) {
// Condition for removing an unused LoadNode or DecodeNNode from the MemBarAcquire precedence input
return n->Opcode() == Op_MemBarAcquire;
} else if (op == Op_AddL) {
// Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
return n->Opcode() == Op_ConvL2I && n->in(1) == this;
} else if (op == Op_SubI || op == Op_SubL) {
// Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
return n->Opcode() == op && n->in(2) == this;
} else if (is_If() && (n->is_IfFalse() || n->is_IfTrue())) {
// See IfProjNode::Identity()
return true;
} else if ((is_IfFalse() || is_IfTrue()) && n->is_If()) {
// See IfNode::fold_compares
return true;
} else {
return false;
}
};
//--------------------------find_exact_control---------------------------------
// Skip Proj and CatchProj nodes chains. Check for Null and Top.
Node* Node::find_exact_control(Node* ctrl) {
if (ctrl == NULL && this->is_Region())
ctrl = this->as_Region()->is_copy();
if (ctrl != NULL && ctrl->is_CatchProj()) {
if (ctrl->as_CatchProj()->_con == CatchProjNode::fall_through_index)
ctrl = ctrl->in(0);
if (ctrl != NULL && !ctrl->is_top())
ctrl = ctrl->in(0);
}
if (ctrl != NULL && ctrl->is_Proj())
ctrl = ctrl->in(0);
return ctrl;
}
//--------------------------dominates------------------------------------------
// Helper function for MemNode::all_controls_dominate().
// Check if 'this' control node dominates or equal to 'sub' control node.
// We already know that if any path back to Root or Start reaches 'this',
// then all paths so, so this is a simple search for one example,
// not an exhaustive search for a counterexample.
bool Node::dominates(Node* sub, Node_List &nlist) {
assert(this->is_CFG(), "expecting control");
assert(sub != NULL && sub->is_CFG(), "expecting control");
// detect dead cycle without regions
int iterations_without_region_limit = DominatorSearchLimit;
Node* orig_sub = sub;
Node* dom = this;
bool met_dom = false;
nlist.clear();
// Walk 'sub' backward up the chain to 'dom', watching for regions.
// After seeing 'dom', continue up to Root or Start.
// If we hit a region (backward split point), it may be a loop head.
// Keep going through one of the region's inputs. If we reach the
// same region again, go through a different input. Eventually we
// will either exit through the loop head, or give up.
// (If we get confused, break out and return a conservative 'false'.)
while (sub != NULL) {
if (sub->is_top()) break; // Conservative answer for dead code.
if (sub == dom) {
if (nlist.size() == 0) {
// No Region nodes except loops were visited before and the EntryControl
// path was taken for loops: it did not walk in a cycle.
return true;
} else if (met_dom) {
break; // already met before: walk in a cycle
} else {
// Region nodes were visited. Continue walk up to Start or Root
// to make sure that it did not walk in a cycle.
met_dom = true; // first time meet
iterations_without_region_limit = DominatorSearchLimit; // Reset
}
}
if (sub->is_Start() || sub->is_Root()) {
// Success if we met 'dom' along a path to Start or Root.
// We assume there are no alternative paths that avoid 'dom'.
// (This assumption is up to the caller to ensure!)
return met_dom;
}
Node* up = sub->in(0);
// Normalize simple pass-through regions and projections:
up = sub->find_exact_control(up);
// If sub == up, we found a self-loop. Try to push past it.
if (sub == up && sub->is_Loop()) {
// Take loop entry path on the way up to 'dom'.
up = sub->in(1); // in(LoopNode::EntryControl);
} else if (sub == up && sub->is_Region() && sub->req() == 2) {
// Take in(1) path on the way up to 'dom' for regions with only one input
up = sub->in(1);
} else if (sub == up && sub->is_Region() && sub->req() == 3) {
// Try both paths for Regions with 2 input paths (it may be a loop head).
// It could give conservative 'false' answer without information
// which region's input is the entry path.
iterations_without_region_limit = DominatorSearchLimit; // Reset
bool region_was_visited_before = false;
// Was this Region node visited before?
// If so, we have reached it because we accidentally took a
// loop-back edge from 'sub' back into the body of the loop,
// and worked our way up again to the loop header 'sub'.
// So, take the first unexplored path on the way up to 'dom'.
for (int j = nlist.size() - 1; j >= 0; j--) {
intptr_t ni = (intptr_t)nlist.at(j);
Node* visited = (Node*)(ni & ~1);
bool visited_twice_already = ((ni & 1) != 0);
if (visited == sub) {
if (visited_twice_already) {
// Visited 2 paths, but still stuck in loop body. Give up.
return false;
}
// The Region node was visited before only once.
// (We will repush with the low bit set, below.)
nlist.remove(j);
// We will find a new edge and re-insert.
region_was_visited_before = true;
break;
}
}
// Find an incoming edge which has not been seen yet; walk through it.
assert(up == sub, "");
uint skip = region_was_visited_before ? 1 : 0;
for (uint i = 1; i < sub->req(); i++) {
Node* in = sub->in(i);
if (in != NULL && !in->is_top() && in != sub) {
if (skip == 0) {
up = in;
break;
}
--skip; // skip this nontrivial input
}
}
// Set 0 bit to indicate that both paths were taken.
nlist.push((Node*)((intptr_t)sub + (region_was_visited_before ? 1 : 0)));
}
if (up == sub) {
break; // some kind of tight cycle
}
if (up == orig_sub && met_dom) {
// returned back after visiting 'dom'
break; // some kind of cycle
}
if (--iterations_without_region_limit < 0) {
break; // dead cycle
}
sub = up;
}
// Did not meet Root or Start node in pred. chain.
// Conservative answer for dead code.
return false;
}
//------------------------------remove_dead_region-----------------------------
// This control node is dead. Follow the subgraph below it making everything
// using it dead as well. This will happen normally via the usual IterGVN
// worklist but this call is more efficient. Do not update use-def info
// inside the dead region, just at the borders.
static void kill_dead_code( Node *dead, PhaseIterGVN *igvn ) {
// Con's are a popular node to re-hit in the hash table again.
if( dead->is_Con() ) return;
ResourceMark rm;
Node_List nstack;
Node *top = igvn->C->top();
nstack.push(dead);
bool has_irreducible_loop = igvn->C->has_irreducible_loop();
while (nstack.size() > 0) {
dead = nstack.pop();
if (dead->Opcode() == Op_SafePoint) {
dead->as_SafePoint()->disconnect_from_root(igvn);
}
if (dead->outcnt() > 0) {
// Keep dead node on stack until all uses are processed.
nstack.push(dead);
// For all Users of the Dead... ;-)
for (DUIterator_Last kmin, k = dead->last_outs(kmin); k >= kmin; ) {
Node* use = dead->last_out(k);
igvn->hash_delete(use); // Yank from hash table prior to mod
if (use->in(0) == dead) { // Found another dead node
assert (!use->is_Con(), "Control for Con node should be Root node.");
use->set_req(0, top); // Cut dead edge to prevent processing
nstack.push(use); // the dead node again.
} else if (!has_irreducible_loop && // Backedge could be alive in irreducible loop
use->is_Loop() && !use->is_Root() && // Don't kill Root (RootNode extends LoopNode)
use->in(LoopNode::EntryControl) == dead) { // Dead loop if its entry is dead
use->set_req(LoopNode::EntryControl, top); // Cut dead edge to prevent processing
use->set_req(0, top); // Cut self edge
nstack.push(use);
} else { // Else found a not-dead user
// Dead if all inputs are top or null
bool dead_use = !use->is_Root(); // Keep empty graph alive
for (uint j = 1; j < use->req(); j++) {
Node* in = use->in(j);
if (in == dead) { // Turn all dead inputs into TOP
use->set_req(j, top);
} else if (in != NULL && !in->is_top()) {
dead_use = false;
}
}
if (dead_use) {
if (use->is_Region()) {
use->set_req(0, top); // Cut self edge
}
nstack.push(use);
} else {
igvn->_worklist.push(use);
}
}
// Refresh the iterator, since any number of kills might have happened.
k = dead->last_outs(kmin);
}
} else { // (dead->outcnt() == 0)
// Done with outputs.
igvn->hash_delete(dead);
igvn->_worklist.remove(dead);
igvn->set_type(dead, Type::TOP);
// Kill all inputs to the dead guy
for (uint i=0; i < dead->req(); i++) {
Node *n = dead->in(i); // Get input to dead guy
if (n != NULL && !n->is_top()) { // Input is valid?
dead->set_req(i, top); // Smash input away
if (n->outcnt() == 0) { // Input also goes dead?
if (!n->is_Con())
nstack.push(n); // Clear it out as well
} else if (n->outcnt() == 1 &&
n->has_special_unique_user()) {
igvn->add_users_to_worklist( n );
} else if (n->outcnt() <= 2 && n->is_Store()) {
// Push store's uses on worklist to enable folding optimization for
// store/store and store/load to the same address.
// The restriction (outcnt() <= 2) is the same as in set_req_X()
// and remove_globally_dead_node().
igvn->add_users_to_worklist( n );
} else {
BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(igvn, n);
}
}
}
igvn->C->remove_useless_node(dead);
} // (dead->outcnt() == 0)
} // while (nstack.size() > 0) for outputs
return;
}
//------------------------------remove_dead_region-----------------------------
bool Node::remove_dead_region(PhaseGVN *phase, bool can_reshape) {
Node *n = in(0);
if( !n ) return false;
// Lost control into this guy? I.e., it became unreachable?
// Aggressively kill all unreachable code.
if (can_reshape && n->is_top()) {
kill_dead_code(this, phase->is_IterGVN());
return false; // Node is dead.
}
if( n->is_Region() && n->as_Region()->is_copy() ) {
Node *m = n->nonnull_req();
set_req(0, m);
return true;
}
return false;
}
//------------------------------hash-------------------------------------------
// Hash function over Nodes.
uint Node::hash() const {
uint sum = 0;
for( uint i=0; i<_cnt; i++ ) // Add in all inputs
sum = (sum<<1)-(uintptr_t)in(i); // Ignore embedded NULLs
return (sum>>2) + _cnt + Opcode();
}
//------------------------------cmp--------------------------------------------
// Compare special parts of simple Nodes
bool Node::cmp( const Node &n ) const {
return true; // Must be same
}
//------------------------------rematerialize-----------------------------------
// Should we clone rather than spill this instruction?
bool Node::rematerialize() const {
if ( is_Mach() )
return this->as_Mach()->rematerialize();
else
return (_flags & Flag_rematerialize) != 0;
}
//------------------------------needs_anti_dependence_check---------------------
// Nodes which use memory without consuming it, hence need antidependences.
bool Node::needs_anti_dependence_check() const {
if (req() < 2 || (_flags & Flag_needs_anti_dependence_check) == 0) {
return false;
}
return in(1)->bottom_type()->has_memory();
}
// Get an integer constant from a ConNode (or CastIINode).
// Return a default value if there is no apparent constant here.
const TypeInt* Node::find_int_type() const {
if (this->is_Type()) {
return this->as_Type()->type()->isa_int();
} else if (this->is_Con()) {
assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
return this->bottom_type()->isa_int();
}
return NULL;
}
const TypeInteger* Node::find_integer_type(BasicType bt) const {
if (this->is_Type()) {
return this->as_Type()->type()->isa_integer(bt);
} else if (this->is_Con()) {
assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
return this->bottom_type()->isa_integer(bt);
}
return NULL;
}
// Get a pointer constant from a ConstNode.
// Returns the constant if it is a pointer ConstNode
intptr_t Node::get_ptr() const {
assert( Opcode() == Op_ConP, "" );
return ((ConPNode*)this)->type()->is_ptr()->get_con();
}
// Get a narrow oop constant from a ConNNode.
intptr_t Node::get_narrowcon() const {
assert( Opcode() == Op_ConN, "" );
return ((ConNNode*)this)->type()->is_narrowoop()->get_con();
}
// Get a long constant from a ConNode.
// Return a default value if there is no apparent constant here.
const TypeLong* Node::find_long_type() const {
if (this->is_Type()) {
return this->as_Type()->type()->isa_long();
} else if (this->is_Con()) {
assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
return this->bottom_type()->isa_long();
}
return NULL;
}
/**
* Return a ptr type for nodes which should have it.
*/
const TypePtr* Node::get_ptr_type() const {
const TypePtr* tp = this->bottom_type()->make_ptr();
#ifdef ASSERT
if (tp == NULL) {
this->dump(1);
assert((tp != NULL), "unexpected node type");
}
#endif
return tp;
}
// Get a double constant from a ConstNode.
// Returns the constant if it is a double ConstNode
jdouble Node::getd() const {
assert( Opcode() == Op_ConD, "" );
return ((ConDNode*)this)->type()->is_double_constant()->getd();
}
// Get a float constant from a ConstNode.
// Returns the constant if it is a float ConstNode
jfloat Node::getf() const {
assert( Opcode() == Op_ConF, "" );
return ((ConFNode*)this)->type()->is_float_constant()->getf();
}
#ifndef PRODUCT
// Call this from debugger:
Node* old_root() {
Matcher* matcher = Compile::current()->matcher();
if (matcher != nullptr) {
Node* new_root = Compile::current()->root();
Node* old_root = matcher->find_old_node(new_root);
if (old_root != nullptr) {
return old_root;
}
}
tty->print("old_root: not found.\n");
return nullptr;
}
// BFS traverse all reachable nodes from start, call callback on them
template <typename Callback>
void visit_nodes(Node* start, Callback callback, bool traverse_output, bool only_ctrl) {
Unique_Mixed_Node_List worklist;
worklist.add(start);
for (uint i = 0; i < worklist.size(); i++) {
Node* n = worklist[i];
callback(n);
for (uint i = 0; i < n->len(); i++) {
if (!only_ctrl || n->is_Region() || (n->Opcode() == Op_Root) || (i == TypeFunc::Control)) {
// If only_ctrl is set: Add regions, the root node, or control inputs only
worklist.add(n->in(i));
}
}
if (traverse_output && !only_ctrl) {
for (uint i = 0; i < n->outcnt(); i++) {
worklist.add(n->raw_out(i));
}
}
}
}
// BFS traverse from start, return node with idx
Node* find_node_by_idx(Node* start, uint idx, bool traverse_output, bool only_ctrl) {
ResourceMark rm;
Node* result = nullptr;
auto callback = [&] (Node* n) {
if (n->_idx == idx) {
if (result != nullptr) {
tty->print("find_node_by_idx: " INTPTR_FORMAT " and " INTPTR_FORMAT " both have idx==%d\n",
(uintptr_t)result, (uintptr_t)n, idx);
}
result = n;
}
};
visit_nodes(start, callback, traverse_output, only_ctrl);
return result;
}
int node_idx_cmp(const Node** n1, const Node** n2) {
return (*n1)->_idx - (*n2)->_idx;
}
void find_nodes_by_name(Node* start, const char* name) {
ResourceMark rm;
GrowableArray<const Node*> ns;
auto callback = [&] (const Node* n) {
if (StringUtils::is_star_match(name, n->Name())) {
ns.push(n);
}
};
visit_nodes(start, callback, true, false);
ns.sort(node_idx_cmp);
for (int i = 0; i < ns.length(); i++) {
ns.at(i)->dump();
}
}
void find_nodes_by_dump(Node* start, const char* pattern) {
ResourceMark rm;
GrowableArray<const Node*> ns;
auto callback = [&] (const Node* n) {
stringStream stream;
n->dump("", false, &stream);
if (StringUtils::is_star_match(pattern, stream.base())) {
ns.push(n);
}
};
visit_nodes(start, callback, true, false);
ns.sort(node_idx_cmp);
for (int i = 0; i < ns.length(); i++) {
ns.at(i)->dump();
}
}
// call from debugger: find node with name pattern in new/current graph
// name can contain "*" in match pattern to match any characters
// the matching is case insensitive
void find_nodes_by_name(const char* name) {
Node* root = Compile::current()->root();
find_nodes_by_name(root, name);
}
// call from debugger: find node with name pattern in old graph
// name can contain "*" in match pattern to match any characters
// the matching is case insensitive
void find_old_nodes_by_name(const char* name) {
Node* root = old_root();
find_nodes_by_name(root, name);
}
// call from debugger: find node with dump pattern in new/current graph
// can contain "*" in match pattern to match any characters
// the matching is case insensitive
void find_nodes_by_dump(const char* pattern) {
Node* root = Compile::current()->root();
find_nodes_by_dump(root, pattern);
}
// call from debugger: find node with name pattern in old graph
// can contain "*" in match pattern to match any characters
// the matching is case insensitive
void find_old_nodes_by_dump(const char* pattern) {
Node* root = old_root();
find_nodes_by_dump(root, pattern);
}
// Call this from debugger, search in same graph as n:
Node* find_node(Node* n, const int idx) {
return n->find(idx);
}
// Call this from debugger, search in new nodes:
Node* find_node(const int idx) {
return Compile::current()->root()->find(idx);
}
// Call this from debugger, search in old nodes:
Node* find_old_node(const int idx) {
Node* root = old_root();
return (root == nullptr) ? nullptr : root->find(idx);
}
// Call this from debugger, search in same graph as n:
Node* find_ctrl(Node* n, const int idx) {
return n->find_ctrl(idx);
}
// Call this from debugger, search in new nodes:
Node* find_ctrl(const int idx) {
return Compile::current()->root()->find_ctrl(idx);
}
// Call this from debugger, search in old nodes:
Node* find_old_ctrl(const int idx) {
Node* root = old_root();
return (root == nullptr) ? nullptr : root->find_ctrl(idx);
}
//------------------------------find_ctrl--------------------------------------
// Find an ancestor to this node in the control history with given _idx
Node* Node::find_ctrl(int idx) {
return find(idx, true);
}
//------------------------------find-------------------------------------------
// Tries to find the node with the index |idx| starting from this node. If idx is negative,
// the search also includes forward (out) edges. Returns NULL if not found.
// If only_ctrl is set, the search will only be done on control nodes. Returns NULL if
// not found or if the node to be found is not a control node (search will not find it).
Node* Node::find(const int idx, bool only_ctrl) {
ResourceMark rm;
return find_node_by_idx(this, abs(idx), (idx < 0), only_ctrl);
}
class PrintBFS {
public:
PrintBFS(const Node* start, const int max_distance, const Node* target, const char* options)
: _start(start), _max_distance(max_distance), _target(target), _options(options),
_dcc(this), _info_uid(cmpkey, hashkey) {}
void run();
private:
// pipeline steps
bool configure();
void collect();
void select();
void select_all();
void select_all_paths();
void select_shortest_path();
void sort();
void print();
// inputs
const Node* _start;
const int _max_distance;
const Node* _target;
const char* _options;
// options
bool _traverse_inputs = false;
bool _traverse_outputs = false;
struct Filter {
bool _control = false;
bool _memory = false;
bool _data = false;
bool _mixed = false;
bool _other = false;
bool is_empty() const {
return !(_control || _memory || _data || _mixed || _other);
}
void set_all() {
_control = true;
_memory = true;
_data = true;
_mixed = true;
_other = true;
}
// Check if the filter accepts the node. Go by the type categories, but also all CFG nodes
// are considered to have control.
bool accepts(const Node* n) {
const Type* t = n->bottom_type();
return ( _data && t->has_category(Type::Category::Data) ) ||
( _memory && t->has_category(Type::Category::Memory) ) ||
( _mixed && t->has_category(Type::Category::Mixed) ) ||
( _control && (t->has_category(Type::Category::Control) || n->is_CFG()) ) ||
( _other && t->has_category(Type::Category::Other) );
}
};
Filter _filter_visit;
Filter _filter_boundary;
bool _sort_idx = false;
bool _all_paths = false;
bool _use_color = false;
bool _print_blocks = false;
bool _print_old = false;
bool _dump_only = false;
static void print_options_help(bool print_examples);
bool parse_options();
public:
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