/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* 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 "classfile/systemDictionary.hpp"
#include "compiler/compileLog.hpp"
#include "memory/allocation.inline.hpp"
#include "oops/objArrayKlass.hpp"
#include "opto/addnode.hpp"
#include "opto/cfgnode.hpp"
#include "opto/compile.hpp"
#include "opto/connode.hpp"
#include "opto/loopnode.hpp"
#include "opto/machnode.hpp"
#include "opto/matcher.hpp"
#include "opto/memnode.hpp"
#include "opto/mulnode.hpp"
#include "opto/phaseX.hpp"
#include "opto/regmask.hpp"
// Portions of code courtesy of Clifford Click
// Optimization - Graph Style
static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem, const TypePtr *tp, const TypePtr *adr_check, outputStream *st);
//=============================================================================
}
#ifndef PRODUCT
#ifndef ASSERT
// fake the missing field
#endif
}
} else {
else {
if (field) {
}
}
}
}
extern void print_alias_types();
#endif
return mchain; // don't try to optimize non-instance types
break; // hit one of our sentinels
// skip over a call which does not affect this memory slice
break; // hit one of our sentinels
}
} else if (proj_in->is_Initialize()) {
// Stop if this is the initialization for the object instance which
// which contains this memory slice, otherwise skip over it.
}
} else {
assert(false, "unexpected projection");
}
} else if (result->is_ClearArray()) {
// Can not bypass initialization of the instance
// we are looking for.
break;
}
// Otherwise skip it (the call updated 'result' value).
} else if (result->is_MergeMem()) {
}
}
return result;
}
t->is_oopptr()->cast_to_exactness(true)
// clone the Phi with our address type
} else {
}
}
return result;
}
static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem, const TypePtr *tp, const TypePtr *adr_check, outputStream *st) {
#ifdef ASSERT
{
// Check that current type is consistent with the alias index used during graph construction
// Sometimes dead array references collapse to a[-1], a[-2], or a[-3]
// don't assert if it is dead code.
consistent = true;
}
if( !consistent ) {
} else {
}
}
}
#endif
// TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
// means an array I have not precisely typed yet. Do not do any
// alias stuff with it any time soon.
!(toop &&
// compress paths and change unreachable cycles to TOP
// If not, we can update the input infinitely along a MergeMem cycle
// Equivalent code in PhiNode::Ideal
// If transformed to a MergeMem, get the desired slice
// Otherwise the returned node represents memory for every slice
// Update input if it is progress over what we have now
}
return mem;
}
//--------------------------Ideal_common---------------------------------------
// Look for degenerate control and memory inputs. Bypass MergeMem inputs.
// Unhook non-raw memories from complete (macro-expanded) initializations.
// If our control input is a dead region, kill all below the region
return this;
// Don't bother trying to transform a dead node
// Wait if control on the worklist.
}
// This control path may be dead.
// Delay this memory node transformation until the control is processed.
return NodeSentinel; // caller will return NULL
}
}
// Ignore if memory is dead, or self-loop
// This memory slice may be dead.
// Delay this mem node transformation until the memory is processed.
return NodeSentinel; // caller will return NULL
}
// The address's base and type may change when the address is processed.
// Delay this mem node transformation until the address is processed.
return NodeSentinel; // caller will return NULL
}
// Do NOT remove or optimize the next lines: ensure a new alias index
// is allocated for an oop pointer type before Escape Analysis.
// Note: C++ will not remove it since the call has side effect.
if (t_adr->isa_oopptr()) {
}
#ifdef ASSERT
!t_adr->isa_rawptr()) {
// Note: raw address has TOP base and top->higher_equal(TypePtr::NULL_PTR) is true.
this->dump(2);
}
#endif
// Avoid independent memory operations
// The code which unhooks non-raw memories from complete (macro-expanded)
// initializations was removed. After macro-expansion all stores catched
// by Initialize node became raw stores and there is no information
// which memory slices they modify. So it is unsafe to move any memory
// operation above these stores. Also in most cases hooked non-raw memories
// were already unhooked by using information from detect_ptr_independence()
// and find_previous_store().
if (mem->is_MergeMem()) {
}
}
return this;
}
// let the subclass continue analyzing...
return NULL;
}
// Helper function for proving some simple control dominations.
// Attempt to prove that all control inputs of 'dom' dominate 'sub'.
// Already assumes that 'dom' is available at 'sub', and that 'sub'
// is not a constant (dominated by the method's StartNode).
// Used by MemNode::find_previous_store to prove that the
// control input of a memory operation predates (dominates)
// an allocation it wants to look past.
return false; // Conservative answer for dead code
// Check 'dom'. Skip Proj and CatchProj nodes.
return false; // Conservative answer for dead code
// For the case when, for example, 'sub' is Initialize and the original
// 'dom' is Proj node of the 'sub'.
return false;
}
return true;
// 'dom' dominates 'sub' if its control edge and control edges
// of all its inputs dominate or equal to sub's control edge.
// Currently 'sub' is either Allocate, Initialize or Start nodes.
// Or Region for the check in LoadNode::Ideal();
// 'sub' should have sub->in(0) != NULL.
// Get control edge of 'sub'.
return false; // Conservative answer for dead code
return true;
return false;
{
// Check all control edges of 'dom'.
bool only_dominating_controls = false;
if (n == orig_sub)
return false; // One of dom's inputs dominated by sub.
// Check only own control edge for pinned non-control nodes.
n = n->find_exact_control(n->in(0));
return false; // Conservative answer for dead code
only_dominating_controls = true;
} else if (n->is_CFG()) {
only_dominating_controls = true;
else
return false;
} else {
// First, own control edge.
if (m != NULL) {
if (m->is_top())
return false; // Conservative answer for dead code
}
// Now, the rest of edges.
m = n->find_exact_control(n->in(i));
continue;
}
}
}
return only_dominating_controls;
}
}
//---------------------detect_ptr_independence---------------------------------
// Used by MemNode::find_previous_store to prove that two base
// pointers are never equal.
// The pointers are accompanied by their associated allocations,
// if any, which have been previously discovered by the caller.
PhaseTransform* phase) {
// Attempt to prove that these two pointers cannot be aliased.
// They may both manifestly be allocations, and they should differ.
// Or, if they are not both allocations, they can be distinct constants.
// Otherwise, one is an allocation and the other a pre-existing value.
// (Note: p2->is_Con implies p2->in(0)->is_Root, which dominates.)
} else { //(a2 != NULL) // one allocation a2
}
return false;
}
// The logic for reordering loads and stores uses four steps:
// (a) Walk carefully past stores and initializations which we
// can prove are independent of this load.
// (b) Observe that the next memory state makes an exact match
// with self (load or store), and locate the relevant store.
// (c) Ensure that, if we were to wire self directly to the store,
// the optimizer would fold it up somehow.
// (d) Do the rewiring, and return, depending on some other part of
// the optimizer to fold up the load.
// This routine handles steps (a) and (b). Steps (c) and (d) are
// specific to loads and stores, so they are handled by the callers.
// (Currently, only LoadNode::Ideal has steps (c), (d). More later.)
//
return NULL; // cannot unalias unless there are precise offsets
for (;;) { // While we can dance past unrelated stores...
if (--cnt < 0) break; // Caught in cycle or a complicated dance?
break; // inscrutable pointer
// Success: The offsets are provably independent.
// (You may ask, why not just test st_offset != offset and be done?
// The answer is that stores of different sizes can co-exist
// in the same sequence of RawMem effects. We sometimes initialize
// a whole 'tile' of array elements with a single jint or jlong.)
continue; // (a) advance through independent store memory
}
}
phase)) {
// Success: The bases are provably independent.
continue; // (a) advance through independent store memory
}
// (b) At this point, if the bases or offsets do not agree, we lose,
// since we have not managed to prove 'this' and 'mem' independent.
return mem; // let caller handle steps (c), (d)
}
break; // something degenerated
bool known_identical = false;
bool known_independent = false;
known_identical = true;
known_independent = true;
else if (all_controls_dominate(this, st_alloc))
known_independent = true;
if (known_independent) {
// The bases are provably independent: Either they are
// manifestly distinct allocations, or else the control
// of this load dominates the store's allocation.
} else {
}
continue; // (a) advance through independent store memory
}
// (b) at this point, if we are not looking at a store initializing
// the same allocation we are loading from, we lose.
if (known_identical) {
// From caller, can_see_stored_value will consult find_captured_store.
return mem; // let caller handle steps (c), (d)
}
// Can't use optimize_simple_memory_chain() since it needs PhaseGVN.
continue; // (a) advance through independent call memory
}
continue; // (a) advance through independent MemBar memory
} else if (mem->is_ClearArray()) {
// (the call updated 'mem' value)
continue; // (a) advance through independent allocation memory
} else {
// Can not bypass initialization of the instance
// we are looking for.
return mem;
}
} else if (mem->is_MergeMem()) {
continue; // (a) advance through independent MergeMem memory
}
}
// Unless there is an explicit 'continue', we must bail out here,
// because 'mem' is an inscrutable memory state (e.g., a call).
break;
}
return NULL; // bail out
}
//----------------------calculate_adr_type-------------------------------------
// Helper function. Notices when the given type of address hits top or bottom.
// Also, asserts a cross-check of the type against the expected address type.
#ifdef PRODUCT
cross_check = NULL;
#else
#endif
} else {
#ifdef ASSERT
// %%%% [phh] We don't check the alias index if cross_check is
// TypeRawPtr::BOTTOM. Needs to be investigated.
if (cross_check != NULL &&
// Recheck the alias index, to see if it has changed (due to a bug).
"must stay in the original alias category");
// The type of the address must be contained in the adr_type,
// disregarding "null"-ness.
// (We make an exception for TypeRawPtr::BOTTOM, which is a bit bucket.)
"real address must not escape from expected memory type");
}
#endif
return tp;
}
}
//------------------------adr_phi_is_loop_invariant----------------------------
// A helper function for Ideal_DU_postCCP to check if a Phi in a counted
// loop is loop invariant. Make a quick traversal of Phi and associated
// CastPP nodes, looking to see if they are a closed group within the loop.
// The idea is that the phi-nest must boil down to only CastPP nodes
// with the same data. This implies that any path into the loop already
// includes such a CastPP, and so the original cast, whatever its input,
// must be covered by an equivalent cast, with an earlier control input.
// The loop entry input of the phi should be the unique dominating
// Add the phi node and the cast to the worklist.
if( !cast->is_ConstraintCast() ) return false;
}
// Begin recursive walk of phi nodes.
// Take a node off the worklist
// Add it to the closure.
// Make a sanity check to ensure we don't waste too much time here.
// This node is OK if:
// - it is a cast of an identical value
// - or it is a phi node (then we add its inputs to the worklist)
// Otherwise, the node is not OK, and we presume the cast is not invariant
if( n->is_ConstraintCast() ){
} else if( n->is_Phi() ) {
}
} else {
return false;
}
}
}
// Quit when the worklist is empty, and we've found no offending nodes.
return true;
}
//------------------------------Ideal_DU_postCCP-------------------------------
// Find any cast-away of null-ness and keep its control. Null cast-aways are
// going away in this pass and we need to make this memory op depend on the
// gating null check.
}
// I tried to leave the CastPP's in. This makes the graph more accurate in
// some sense; we get to keep around the knowledge that an oop is not-null
// after some test. Alas, the CastPP's interfere with GVN (some values are
// the regular oop, some are the CastPP of the oop, all merge at Phi's which
// cannot collapse, etc). This cost us 10% on SpecJVM, even when I removed
// some of the more trivial cases in the optimizer. Removing more useless
// Phi's started allowing Loads to illegally float above null checks. I gave
// up on this approach. CNC 10/20/2000
// This static method may be called not from MemNode (EncodePNode calls it).
// Only the control edge of the node 'n' might be updated.
// Need a null check? Regular static accesses do not because they are
// from constant addresses. Array ops are gated by the range check (which
// always includes a NULL check). Just check field ops.
// Scan upwards for the highest location we can place this memory op.
while( true ) {
case Op_AddP: // No change to NULL-ness, so peek thru AddP's
continue;
case Op_DecodeN: // No change to NULL-ness, so peek thru
continue;
case Op_EncodeP:
// EncodeP node's control edge could be set by this method
// when EncodeP node depends on CastPP node.
//
// Use its control edge for memory op because EncodeP may go away
// later when it is folded with following or preceding DecodeN node.
// Keep looking for cast nodes.
continue;
}
ccp->hash_delete(n);
ccp->hash_insert(n);
return n;
case Op_CastPP:
// If the CastPP is useless, just peek on through it.
// Remember the cast that we've peeked though. If we peek
// through more than one, then we end up remembering the highest
// one, that is, if in a loop, the one closest to the top.
skipped_cast = adr;
continue;
}
// CastPP is going away in this pass! We need this memory op to be
// control-dependent on the test that is guarding the CastPP.
ccp->hash_delete(n);
ccp->hash_insert(n);
return n;
case Op_Phi:
// Attempt to float above a Phi to some dominating point.
// If we've already peeked through a Cast (which could have set the
// control), we can't float above a Phi, because the skipped Cast
// may not be loop invariant.
continue;
}
}
// Intentional fallthrough!
// No obvious dominating point. The mem op is pinned below the Phi
// by the Phi itself. If the Phi goes away (no true value is merged)
// then the mem op can float, but not indefinitely. It must be pinned
// behind the controls leading to the Phi.
case Op_CheckCastPP:
// These usually stick around to change address type, however a
// useless one can be elided and we still need to pick up a control edge
// This CheckCastPP node has NO control and is likely useless. But we
// need check further up the ancestor chain for a control input to keep
// the node in place. 4959717.
skipped_cast = adr;
continue;
}
ccp->hash_delete(n);
ccp->hash_insert(n);
return n;
// List of "safe" opcodes; those that implicitly block the memory
// op below any null check.
case Op_CastX2P: // no null checks on native pointers
case Op_Parm: // 'this' pointer is not null
case Op_LoadP: // Loading from within a klass
case Op_LoadN: // Loading from within a klass
case Op_LoadKlass: // Loading from within a klass
case Op_LoadNKlass: // Loading from within a klass
case Op_ConP: // Loading from a klass
case Op_ConN: // Loading from a klass
case Op_CreateEx: // Sucking up the guts of an exception oop
case Op_Con: // Reading from TLS
case Op_CMoveP: // CMoveP is pinned
case Op_CMoveN: // CMoveN is pinned
break; // No progress
case Op_Proj: // Direct call to an allocation routine
case Op_SCMemProj: // Memory state from store conditional ops
#ifdef ASSERT
{
if (call->is_CallJava()) {
// We further presume that this is one of
// new_instance_Java, new_array_Java, or
// the like, but do not assert for this.
} else if (call->is_Allocate()) {
// similar case to new_instance_Java, etc.
} else if (!call->is_CallLeaf()) {
// Projections from fetch_oop (OSR) are allowed as well.
}
}
#endif
break;
default:
}
break;
}
}
return NULL; // No progress
}
//=============================================================================
}
#ifndef PRODUCT
if( !Verbose && !WizardMode ) {
// standard dump does this in Verbose and WizardMode
}
}
#endif
#ifdef ASSERT
//----------------------------is_immutable_value-------------------------------
// Helper function to allow a raw load without control edge for some cases
}
#endif
//----------------------------LoadNode::make-----------------------------------
// Polymorphic factory method:
Node *LoadNode::make( PhaseGVN& gvn, Node *ctl, Node *mem, Node *adr, const TypePtr* adr_type, const Type *rt, BasicType bt ) {
// sanity check the alias category against the created node type
"use LoadKlassNode instead");
"use LoadRangeNode instead");
// Check control edge of raw loads
// oop will be recorded in oop map if load crosses safepoint
"raw memory operations should have control edge");
switch (bt) {
case T_OBJECT:
#ifdef _LP64
} else
#endif
{
}
}
}
LoadLNode* LoadLNode::make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, const Type* rt) {
bool require_atomic = true;
}
//------------------------------hash-------------------------------------------
// unroll addition of interesting fields
}
//---------------------------can_see_stored_value------------------------------
// This routine exists to make sure this set of tests is done the same
// everywhere. We need to make a coordinated change: first LoadNode::Ideal
// will change the graph shape in a way which makes memory alive twice at the
// same time (uses the Oracle model of aliasing), then some
// LoadXNode::Identity will fold things back to the equivalence-class model
// of aliasing.
// Skip through chains of MemBarNodes checking the MergeMems for
// new states for the slice of this load. Stop once any other
// kind of node is encountered. Loads from final memory can skip
// through any kind of MemBar but normal loads shouldn't skip
// through MemBarAcquire since the could allow them to move out of
// a synchronized region.
opc == Op_MemBarReleaseLock) {
if (mem->is_MergeMem()) {
// Keep searching
continue;
}
// Save the new memory state for the slice and fall through
// to exit.
}
}
break;
}
}
}
// Loop around twice in the case Load -> Initialize -> Store.
// (See PhaseIterGVN::add_users_to_worklist, which knows about this case.)
// Try harder before giving up... Match raw and non-raw pointers.
// At this point we have proven something like this setup:
// A = Allocate(...)
// L = LoadQ(, AddP(CastPP(, A.Parm),, #Off))
// S = StoreQ(, AddP(, A.Parm , #Off), V)
// (Actually, we haven't yet proven the Q's are the same.)
// In other words, we are loading from a casted version of
// the same pointer-and-offset that we stored to.
// Thus, we are able to replace L by V.
}
// Now prove that we have a LoadQ matched to a StoreQ, for some Q.
return NULL;
}
// A load from a freshly-created object always returns zero.
// (This can happen after LoadNode::Ideal resets the load's memory input
// to find_captured_store, which returned InitializeNode::zero_memory.)
// return a zero value for the load's basic type
// (This is one of the few places where a generic PhaseTransform
// can create new nodes. Think of it as lazily manifesting
// virtually pre-existing constants.)
}
// A load from an initialization barrier can match a captured store.
// examine a captured store value
continue; // take one more trip around
}
}
break;
}
return NULL;
}
//----------------------is_instance_field_load_with_local_phi------------------
// Only instances.
return true;
}
}
return false;
}
//------------------------------Identity---------------------------------------
// Loads are identity if previous store is to same address
// If the previous store-maker is the right kind of Store, and the store is
// to the same address, then we are equal to the value stored.
if( value ) {
// byte, short & char stores truncate naturally.
// A load has to load the truncated value which requires
// some sort of masking operation and that requires an
// Ideal call instead of an Identity call.
if (memory_size() < BytesPerInt) {
// If the input to the store does not fit with the load's result type,
// it must be truncated via an Ideal call.
return this;
}
// (This works even when value is a Con, but LoadNode::Value
// usually runs first, producing the singleton type of the Con.)
return value;
}
// Search for an existing data phi which was generated before for the same
// instance's field to avoid infinite generation of phis in a loop.
return phi;
}
}
}
return this;
}
// Returns true if the AliasType refers to the field that holds the
// cached box array. Currently only handles the IntegerCache case.
return true;
}
}
return false;
}
// Fetch the base value in the autobox array
// Fetch the box object at the base of the array and get its value
// This should be true nonstatic_field_at requires calling
// nof_nonstatic_fields so check it anyway
cache_offset = c.as_int();
}
return true;
}
}
return false;
}
// Returns true if the AliasType refers to the value field of an
// autobox object. Currently only handles Integer.
return true;
}
}
return false;
}
// We're loading from an object which has autobox behaviour.
// If this object is result of a valueOf call we'll have a phi
// merging a newly allocated object and a load from the cache.
// We want to replace this load with the original incoming
// argument to the valueOf call.
if (allocation != NULL) {
allocation_index = i;
break;
}
}
// Push the loads from the phi that comes from valueOf up
// through it to allow elimination of the loads and the recovery
// of the original value.
return result;
}
if (base->is_DecodeN()) {
// Get LoadN node which loads cached Integer object
}
// Eliminate the load of Integer.value for integers from the cache
// array by deriving the value from the index into the array.
// Capture the offset of the load and then reverse the computation.
if (load_base->is_DecodeN()) {
// Get LoadN node which loads IntegerCache.cache field
}
if (is_autobox_cache(atp)) {
}
int cache_low;
// Add up all the offsets making of the address of the load
for (int i = 1; i < count; i++) {
}
// Remove the constant offset from the address and then
// remove the scaling of the offset to recover the original index.
// Peel the shift off directly but wrap it in a dummy node
// since Ideal can't return existing nodes
} else {
}
#ifdef _LP64
#endif
return result;
}
}
}
}
return NULL;
}
//------------------------------split_through_phi------------------------------
// Split instance field load through Phi.
return NULL; // Wait stable graph
}
return NULL; // Wait stable graph
return NULL; // Wait stable graph
}
}
// Check for loop invariant.
if (cnt == 3) {
if (m == mem) {
return this;
}
}
}
// Split through Phi (see original code in loopopts.cpp).
// Do nothing here if Identity will find a value
// (to avoid infinite chain of value phis generation).
return NULL;
// Skip the split if the region dominates some control edge of the address.
return NULL;
Node *x;
} else {
x = this->clone(); // Else clone up the data op
the_clone = x; // Remember for possible deletion.
// Alter data node to use pre-phi inputs
} else {
}
}
}
// Check for a 'win' on some paths
// See comments in PhaseIdealLoop::split_thru_phi().
}
if (singleton) {
} else {
// We now call Identity to try to simplify the cloned node.
// Note that some Identity methods call phase->type(this).
// Make sure that the type array is big enough for
// our new node, even though we may throw the node away.
// (This tweaking with igvn only works because x is a new node.)
// If x is a TypeNode, capture any more-precise type permanently into Node
// otherwise it will be not updated during igvn->transform since
// igvn->type(x) is set to x->Value() already.
x->raise_bottom_type(t);
if (y != x) {
x = y;
} else {
if (y) {
x = y;
} else {
// Else x is a new node we are keeping
// We do not need register_new_node_with_optimizer
// because set_type has already been called.
}
}
}
}
// Record Phi
return phi;
}
//------------------------------Ideal------------------------------------------
// If the load is from Field memory and the pointer is non-null, we can
// zero out the control input.
// If the offset is constant and the base is an object allocation,
// try to hook me up to the exact initializing store.
if (p) return (p == NodeSentinel) ? NULL : p;
// Skip up past a SafePoint control. Cannot do this for Stores because
// pointer stores & cardmarks must stay on the same side of a SafePoint.
}
// Check for useless control edge in some common special cases
// A method-invariant, non-null address (constant or 'this' argument).
}
if (EliminateAutoBox && can_reshape) {
assert(!phase->type(base)->higher_equal(TypePtr::NULL_PTR), "the autobox pointer should be non-null");
if (is_autobox_object(atp)) {
}
}
}
// try to optimize our memory input
return this;
}
// Delay this transformation until memory Phi is processed.
return NULL;
}
// Split instance field load through Phi.
}
}
// Check for prior store with a different base or offset; make Load
// independent. Skip through any number of them. Bail out if the stores
// are in an endless dead cycle and report no progress. This is a key
// transform for Reflection. However, if after skipping through the Stores
// we can't then fold up against a prior store do NOT do the transform as
// this amounts to using the 'Oracle' model of aliasing. It leaves the same
// array memory alive twice: once for the hoisted Load and again after the
// bypassed Store. This situation only works if EVERYBODY who does
// anti-dependence work knows how to bypass. I.e. we need all
// anti-dependence checks to ask the same Oracle. Right now, that Oracle is
// the alias index stuff. So instead, peek through Stores and IFF we can
// fold up, do so.
// Steps (a), (b): Walk past independent stores to find an exact match.
// (c) See if we can fold up on the spot, but don't fold up here.
// just return a prior value, which is done by Identity calls.
// Make ready for step (d):
return this;
}
}
return NULL; // No further progress
}
// Helper to recognize certain Klass fields which are invariant across
// some group of array types (e.g., int[] or all T[] where T < Object).
const Type*
// The field is Klass::_modifier_flags. Return its (constant) value.
// (Folds up the 2nd indirection in aClassConstant.getModifiers().)
}
// The field is Klass::_access_flags. Return its (constant) value.
// (Folds up the 2nd indirection in Reflection.getClassAccessFlags(aClassConstant).)
}
// The field is Klass::_layout_helper. Return its constant value if known.
}
// No match.
return NULL;
}
//------------------------------Value-----------------------------------------
// Either input is TOP ==> the result is TOP
// Try to guess loaded type from pointer type
// Don't do this for integer types. There is only potential profit if
// the element type t is lower than _type; that is, for int types, if _type is
// more restrictive than t. This only happens here if one is short and the other
// char (both 16 bits), and in those cases we've made an intentional decision
// to use one kind of load over the other. See AndINode::Ideal and 4965907.
// Also, do not try to narrow the type for a LoadKlass, regardless of offset.
//
// Yes, it is possible to encounter an expression like (LoadKlass p1:(AddP x x 8))
// where the _gvn.type of the AddP is wider than 8. This occurs when an earlier
// copy p0 of (AddP x x 8) has been proven equal to p1, and the p0 has been
// subsumed by p1. If p1 is on the worklist but has not yet been re-transformed,
// it is possible that p1 will have a type like Foo*[int+]:NotNull*+any.
// In fact, that could have been the original type of p1, and p1 could have
// had an original form like p1:(AddP x x (LShiftL quux 3)), where the
// expression (LShiftL quux 3) independently optimized to the constant 8.
// t might actually be lower than _type, if _type is a unique
// concrete subclass of abstract class t.
// Make sure the reference is not into the header, by comparing
// the offset against the offset of the start of the array's data.
// Different array types begin at slightly different offsets (12 vs. 16).
// We choose T_BYTE as an example base type that is least restrictive
// as to alignment, which will therefore produce the smallest
// possible base offset.
// In any case, do not allow the join, per se, to empty out the type.
// This can happen if a interface-typed array narrows to a class type.
}
// The pointers in the autobox arrays are always non-null
if (is_autobox_cache(atp)) {
}
}
}
return jt;
}
}
// arrays can be cast to Objects
// unsafe field access may not have a constant offset
C->has_unsafe_access(),
"Field accesses must be precise" );
// For oop loads, we expect the _type to be precise
// For constant Strings treat the final fields as compile time constants.
} else {
}
}
}
}
}
// Optimizations for constant objects
// For constant CallSites treat the target field as a compile time constant.
if (const_oop->is_call_site()) {
ciField* field = call_site->klass()->as_instance_klass()->get_field_by_offset(off, /*is_static=*/ false);
const Type* t;
} else {
}
// Add a dependence for invalidation of the optimization.
if (!call_site->is_constant_call_site()) {
}
return t;
}
}
}
}
// arrays can be cast to Objects
// also allow array-loading from the primary supertype
// array during subtype checks
Opcode() == Op_LoadKlass,
"Field accesses must be precise" );
}
// We are loading a field from a Klass metaobject whose identity
// is known at compile time (the type is "exact" or "precise").
// Check for fields we know are maintained as constants by the VM.
// The field is Klass::_super_check_offset. Return its (constant) value.
// (Folds up type checking code.)
}
// Compute index into primary_supers array
// Check for overflowing; use unsigned compare to handle the negative case.
// The field is an element of Klass::_primary_supers. Return its (constant) value.
// (Folds up type checking code.)
}
&& klass->is_array_klass()) {
// The field is arrayKlass::_component_mirror. Return its (constant) value.
// (Folds up aClassConstant.getComponentType, common in Arrays.copyOf.)
}
// The field is Klass::_java_mirror. Return its (constant) value.
// (Folds up the 2nd indirection in anObjConstant.getClass().)
}
}
// We can still check if we are loading from the primary_supers array at a
// shallow enough depth. Even though the klass is not exact, entries less
// than or equal to its super depth are correct.
while( inner->is_obj_array_klass() )
if( inner->is_instance_klass() &&
// Compute index into primary_supers array
// Check for overflowing; use unsigned compare to handle the negative case.
// The field is an element of Klass::_primary_supers. Return its (constant) value.
// (Folds up type checking code.)
}
}
}
// If the type is enough to determine that the thing is not an array,
// we can give the layout_helper a positive interval type.
// This will help short-circuit some reflective code.
) {
// Note: When interfaces are reliable, we can narrow the interface
// test to (klass != Serializable && klass != Cloneable).
// The key property of this type is that it folds up tests
// for array-ness, since it proves that the layout_helper is positive.
// Thus, a generic value like the basic object layout helper works fine.
}
}
// If we are loading from a freshly-allocated object, produce a zero,
// if the load is provably beyond the header of the object.
// (Also allow a variable load from a fresh array to produce zero.)
if (ReduceFieldZeroing || is_instance) {
return value->bottom_type();
}
}
if (is_instance) {
// If we have an instance type and our memory input is the
// programs's initial memory state, there is no matching store,
// so just return a zero of the appropriate type
}
}
return _type;
}
//------------------------------match_edge-------------------------------------
// Do we Match on this edge index or not? Match only the address.
}
//--------------------------LoadBNode::Ideal--------------------------------------
//
// If the previous store is to the same address as this load,
// and the value stored was larger than a byte, replace this load
// with the value stored truncated to a byte. If no truncation is
// needed, the replacement is done in LoadNode::Identity().
//
}
// Identity call will handle the case where truncation is not needed.
}
// If the input to the store does not fit with the load's result type,
// it must be truncated. We can't delay until Ideal call since
// a singleton Value is needed for split_thru_phi optimization.
}
}
//--------------------------LoadUBNode::Ideal-------------------------------------
//
// If the previous store is to the same address as this load,
// and the value stored was larger than a byte, replace this load
// with the value stored truncated to a byte. If no truncation is
// needed, the replacement is done in LoadNode::Identity().
//
// Identity call will handle the case where truncation is not needed.
}
// If the input to the store does not fit with the load's result type,
// it must be truncated. We can't delay until Ideal call since
// a singleton Value is needed for split_thru_phi optimization.
}
}
//--------------------------LoadUSNode::Ideal-------------------------------------
//
// If the previous store is to the same address as this load,
// and the value stored was larger than a char, replace this load
// with the value stored truncated to a char. If no truncation is
// needed, the replacement is done in LoadNode::Identity().
//
// Identity call will handle the case where truncation is not needed.
}
// If the input to the store does not fit with the load's result type,
// it must be truncated. We can't delay until Ideal call since
// a singleton Value is needed for split_thru_phi optimization.
}
}
//--------------------------LoadSNode::Ideal--------------------------------------
//
// If the previous store is to the same address as this load,
// and the value stored was larger than a short, replace this load
// with the value stored truncated to a short. If no truncation is
// needed, the replacement is done in LoadNode::Identity().
//
}
// Identity call will handle the case where truncation is not needed.
}
// If the input to the store does not fit with the load's result type,
// it must be truncated. We can't delay until Ideal call since
// a singleton Value is needed for split_thru_phi optimization.
}
}
//=============================================================================
//----------------------------LoadKlassNode::make------------------------------
// Polymorphic factory method:
Node *LoadKlassNode::make( PhaseGVN& gvn, Node *mem, Node *adr, const TypePtr* at, const TypeKlassPtr *tk ) {
// sanity check the alias category against the created node type
#ifdef _LP64
if (adr_type->is_ptr_to_narrowoop()) {
}
#endif
}
//------------------------------Value------------------------------------------
return klass_value_common(phase);
}
// Either input is TOP ==> the result is TOP
// Return a more precise klass, if possible
// We are loading a special hidden field from a Class mirror object,
// the field which points to the VM's Klass metaobject.
// java_mirror_type returns non-null for compile-time Class constants.
if (t != NULL) {
// constant oop => constant klass
}
if (!t->is_klass()) {
// a primitive Class (e.g., int.class) has NULL for a klass field
}
// (Folds up the 1st indirection in aClassConstant.getModifiers().)
}
// non-constant mirror, so we can't tell what's going on
}
return _type; // Bail out if not loaded
if (tinst->klass_is_exact()) {
}
// See if we can become precise: no subklasses and no interface
// (Note: We need to support verified interfaces.)
//assert(!UseExactTypes, "this code should be useless with exact types");
// Add a dependence; if any subclass added we need to recompile
// %%% should use stronger assert_unique_concrete_subtype instead
}
// Return precise klass
}
// Return root of possible klass
}
}
// Check for loading klass from an array
if (tary->klass_is_exact()) {
}
// If the klass is an object array, we defer the question to the
// array component klass.
if( ak->is_obj_array_klass() ) {
// See if we can become precise: no subklasses and no interface
//assert(!UseExactTypes, "this code should be useless with exact types");
// Add a dependence; if any subclass added we need to recompile
}
// Return precise array klass
}
}
} else { // Found a type-array?
//assert(!UseExactTypes, "this code should be useless with exact types");
}
}
}
// Check for loading klass from an array klass
return _type; // Bail out if not loaded
if( klass->is_obj_array_klass() &&
// // Always returning precise element type is incorrect,
// // e.g., element type could be object and array may contain strings
// return TypeKlassPtr::make(TypePtr::Constant, elem, 0);
// The array's TypeKlassPtr was declared 'precise' or 'not precise'
// according to the element type's subclassing.
}
// The field is Klass::_super. Return its (constant) value.
// (Folds up the 2nd indirection in aClassConstant.getSuperClass().)
}
}
// Bailout case
}
//------------------------------Identity---------------------------------------
// To clean up reflective code, simplify k.java_mirror.as_klass to plain k.
// Also feed through the klass in Allocate(...klass...)._klass.
return klass_identity_common(phase);
}
if (x != this) return x;
// Take apart the address into an oop and and offset.
// Return 'this' if we cannot.
// We can fetch the klass directly through an AllocateNode.
// This works even if the klass is not constant (clone or newArray).
if (allocated_klass != NULL) {
return allocated_klass;
}
}
// Simplify k.java_mirror.as_klass to plain k, where k is a klassOop.
// Simplify ak.component_mirror.array_klass to plain ak, ak an arrayKlass.
// See inline_native_Class_query for occurrences of these patterns.
// Java Example: x.getClass().isAssignableFrom(y)
// Java Example: Array.newInstance(x.getClass().getComponentType(), n)
//
// This improves reflective code, often making the Class
// mirror go completely dead. (Current exception: Class
// mirrors may appear in debug info, but we could clean them out by
// introducing a new debug info operator for klassOop.java_mirror).
// We are loading a special hidden field from a Class mirror,
// the field which points to its Klass or arrayKlass metaobject.
) {
}
}
}
}
}
return this;
}
//------------------------------Value------------------------------------------
return t;
return t->make_narrowoop();
}
//------------------------------Identity---------------------------------------
// To clean up reflective code, simplify k.java_mirror.as_klass to narrow k.
// Also feed through the klass in Allocate(...klass...)._klass.
if( t->isa_narrowoop()) return x;
}
//------------------------------Value-----------------------------------------
// Either input is TOP ==> the result is TOP
}
//-------------------------------Ideal---------------------------------------
// Feed through the length in AllocateArray(...length...)._length.
if (p) return (p == NodeSentinel) ? NULL : p;
// Take apart the address into an oop and and offset.
// Return 'this' if we cannot.
// We can fetch the length directly through an AllocateArrayNode.
// This works even if the length is not constant (clone or newArray).
if (allocated_length != len) {
// New CastII improves on this.
return len;
}
}
}
return NULL;
}
//------------------------------Identity---------------------------------------
// Feed through the length in AllocateArray(...length...)._length.
if (x != this) return x;
// Take apart the address into an oop and and offset.
// Return 'this' if we cannot.
// We can fetch the length directly through an AllocateArrayNode.
// This works even if the length is not constant (clone or newArray).
// Do not allow make_ideal_length to allocate a CastII node.
if (allocated_length == len) {
// Return allocated_length only if it would not be improved by a CastII.
return allocated_length;
}
}
}
return this;
}
//=============================================================================
//---------------------------StoreNode::make-----------------------------------
// Polymorphic factory method:
StoreNode* StoreNode::make( PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, BasicType bt ) {
switch (bt) {
case T_BOOLEAN:
case T_CHAR:
case T_ADDRESS:
case T_OBJECT:
#ifdef _LP64
} else
#endif
{
}
}
}
StoreLNode* StoreLNode::make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val) {
bool require_atomic = true;
}
//--------------------------bottom_type----------------------------------------
}
//------------------------------hash-------------------------------------------
// unroll addition of interesting fields
//return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address) + (uintptr_t)in(ValueIn);
// Since they are not commoned, do not hash them:
return NO_HASH;
}
//------------------------------Ideal------------------------------------------
// Change back-to-back Store(, p, x) -> Store(m, p, y) to Store(m, p, x).
// When a store immediately follows a relevant allocation/initialization,
// try to capture it into the initialization, or hoist it above.
if (p) return (p == NodeSentinel) ? NULL : p;
// Back-to-back stores to same address? Fold em up. Generally
// unsafe if I have intervening uses... Also disallowed for StoreCM
// since they must follow each StoreP operation. Redundant StoreCMs
// are eliminated just before matching in final_graph_reshape.
// Looking at a dead closed cycle of memory?
"no mismatched stores, except on raw memory");
// If anybody other than 'this' uses 'mem', we cannot fold 'mem' away.
// For example, 'mem' might be the final state at a conditional return.
// Or, 'mem' might be used by some node which is live at the same time
// 'this' is live, which might be unschedulable. So, require exactly
// ONE user, the 'this' store, until such time as we clone 'mem' for
// each of 'mem's uses (thus making the exactly-1-user-rule hold true).
if (can_reshape) { // (%%% is this an anachronism?)
phase->is_IterGVN());
} else {
// It's OK to do this in the parser, since DU info is always accurate,
// and the parser always refers to nodes via SafePointNode maps.
}
return this;
}
}
// Capture an unaliased, unconditional, simple store into an initializer.
// Or, if it is independent of the allocation, hoist it above the allocation.
if (ReduceFieldZeroing && /*can_reshape &&*/
if (offset > 0) {
// If the InitializeNode captured me, it made a raw copy of me,
// and I need to disappear.
// %%% hack to ensure that Ideal returns a new node:
return mem; // fold me away
}
}
}
return NULL; // No further progress
}
//------------------------------Value-----------------------------------------
// Either input is TOP ==> the result is TOP
}
//------------------------------Identity---------------------------------------
// Remove redundant stores:
// Store(m, p, Load(m, p)) changes to m.
// Store(, p, x) -> Store(m, p, x) changes to Store(m, p, x).
// Load then Store? Then the Store is useless
return mem;
}
// Two stores in a row of the same value?
return mem;
}
// Store of zero anywhere into a freshly-allocated object?
// Then the store is useless.
// (It must already have been captured by the InitializeNode.)
// a newly allocated object is already all-zeroes everywhere
return mem;
}
// the store may also apply to zero-bits in an earlier object
// Steps (a), (b): Walk past independent stores to find an exact match.
// prev_val and val might differ by a cast; it would be good
// to keep the more informative of the two.
return mem;
}
}
}
return this;
}
//------------------------------match_edge-------------------------------------
// Do we Match on this edge index or not? Match only memory & value
}
//------------------------------cmp--------------------------------------------
// Do not common stores up together. They generally have to be split
// back up anyways, so do not bother.
return (&n == this); // Always fail except on self
}
//------------------------------Ideal_masked_input-----------------------------
// Check for a useless mask before a partial-word store
// (StoreB ... (AndI valIn conIa) )
// If (conIa & mask == mask) this simplifies to
// (StoreB ... (valIn) )
return this;
}
}
return NULL;
}
//------------------------------Ideal_sign_extended_input----------------------
// Check for useless sign-extension before a partial-word store
// (StoreB ... (RShiftI _ (LShiftI _ valIn conIL ) conIR) )
// If (conIL == conIR && conIR <= num_bits) this simplifies to
// (StoreB ... (valIn) )
return this;
}
}
}
}
return NULL;
}
//------------------------------value_never_loaded-----------------------------------
// Determine whether there are any possible loads of the value stored.
// For simplicity, we actually check if there are any loads from the
// address stored to, not just for loads of the value stored by this node.
//
return false;
if (!adr_oop->is_known_instance_field())
return false; // if not a distinct instance, there may be aliases of the address
return false;
}
}
return true;
}
//=============================================================================
//------------------------------Ideal------------------------------------------
// If the store is from an AND mask that leaves the low bits untouched, then
// we can skip the AND operation. If the store is from a sign-extension
// (a left shift, then right shift) we can skip both.
// Finally check the default case
}
//=============================================================================
//------------------------------Ideal------------------------------------------
// If the store is from an AND mask that leaves the low bits untouched, then
// we can skip the AND operation
// Finally check the default case
}
//=============================================================================
//------------------------------Identity---------------------------------------
// No need to card mark when storing a null ptr
}
}
return this;
}
//=============================================================================
//------------------------------Ideal---------------------------------------
if (my_store->is_MergeMem()) {
return this;
}
return NULL;
}
//------------------------------Value-----------------------------------------
// Either input is TOP ==> the result is TOP
// If extra input is TOP ==> the result is TOP
}
//=============================================================================
//----------------------------------SCMemProjNode------------------------------
{
return bottom_type();
}
//=============================================================================
//----------------------------------LoadStoreNode------------------------------
LoadStoreNode::LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required )
{
}
}
if (x->Opcode() == Op_SCMemProj) continue;
return false;
}
return true;
}
//=============================================================================
//----------------------------------LoadStoreConditionalNode--------------------
LoadStoreConditionalNode::LoadStoreConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex ) : LoadStoreNode(c, mem, adr, val, NULL, TypeInt::BOOL, 5) {
}
//=============================================================================
//-------------------------------adr_type--------------------------------------
// Do we Match on this edge index or not? Do not match memory
}
//------------------------------match_edge-------------------------------------
// Do we Match on this edge index or not? Do not match memory
return idx > 1;
}
//------------------------------Identity---------------------------------------
// Clearing a zero length array does nothing
}
//------------------------------Idealize---------------------------------------
// Clearing a short array is faster with stores
if (!t) return NULL;
// Clearing nothing uses the Identity call.
// Negative clears are possible on dead ClearArrays
// (see jck test stmt114.stmt11402.val).
// Length too long; use fast hardware clear
// adjust atp to be the correct array element address type
// Get base for derived pointer purposes
count--;
while( count-- ) {
}
return mem;
}
//----------------------------step_through----------------------------------
// Return allocation input memory edge if it is different instance
// or itself if it is the one we are looking for.
// This method is called only before Allocate nodes are expanded during
// macro nodes expansion. Before that ClearArray nodes are only generated
// in LibraryCallKit::generate_arraycopy() which follows allocations.
// Can not bypass initialization of the instance we are looking for.
return false;
}
// Otherwise skip it.
else
return true;
}
//----------------------------clear_memory-------------------------------------
// Generate code to initialize object storage to zero.
offset += BytesPerInt;
}
// Initialize the remaining stuff, if any, with a ClearArray.
}
if (start_offset == end_offset) {
// nothing to do
return mem;
}
// Scale to the unit required by the CPU:
if (!Matcher::init_array_count_is_in_bytes) {
}
// Bulk clear double-words
}
if (start_offset == end_offset) {
// nothing to do
return mem;
}
if ((done_offset % BytesPerLong) != 0) {
}
if (done_offset > start_offset) {
}
}
return mem;
}
//=============================================================================
// Do not match memory edge.
}
//------------------------------Ideal------------------------------------------
// Return a node which is more "ideal" than the current node. Strip out
// control copies
// Don't bother trying to transform a dead node
if (can_reshape) {
// If transformed to a MergeMem, get the desired slice
return this;
}
}
return NULL;
}
//------------------------------Value------------------------------------------
return bottom_type();
}
//=============================================================================
{
}
//------------------------------cmp--------------------------------------------
return (&n == this); // Always fail except on self
}
//------------------------------make-------------------------------------------
switch (opcode) {
default: ShouldNotReachHere(); return NULL;
}
}
//------------------------------Ideal------------------------------------------
// Return a node which is more "ideal" than the current node. Strip out
// control copies
// Don't bother trying to transform a dead node
// Eliminate volatile MemBars for scalar replaced objects.
// Volatile field loads and stores.
// The MembarAquire may keep an unused LoadNode alive through the Precedent edge
// if the Precedent is a decodeN and its input (a Load) is used at more than one place,
// replace this Precedent (decodeN) with the Load instead.
} else{
}
}
// Check for scalar replaced object reference.
// Replace MemBar projections by its inputs.
// Must return either the original node (now dead) or a new node
// (Do not return a top here, since that would break the uniqueness of top.)
}
}
}
return NULL;
}
//------------------------------Value------------------------------------------
}
//------------------------------match------------------------------------------
// Construct projections for memory.
}
return NULL;
}
//===========================InitializeNode====================================
// SUMMARY:
// This node acts as a memory barrier on raw memory, after some raw stores.
// The 'cooked' oop value feeds from the Initialize, not the Allocation.
// The Initialize can 'capture' suitably constrained stores as raw inits.
// It can coalesce related raw stores into larger units (called 'tiles').
// It can avoid zeroing new storage for memory units which have raw inits.
// At macro-expansion, it is marked 'complete', and does not optimize further.
//
// EXAMPLE:
// The object 'new short[2]' occupies 16 bytes in a 32-bit machine.
// ctl = incoming control; mem* = incoming memory
// (Note: A star * on a memory edge denotes I/O and other standard edges.)
// First allocate uninitialized memory and fill in the header:
// alloc = (Allocate ctl mem* 16 #short[].klass ...)
// ctl := alloc.Control; mem* := alloc.Memory*
// rawmem = alloc.Memory; rawoop = alloc.RawAddress
// Then initialize to zero the non-header parts of the raw memory block:
// init = (Initialize alloc.Control alloc.Memory* alloc.RawAddress)
// ctl := init.Control; mem.SLICE(#short[*]) := init.Memory
// After the initialize node executes, the object is ready for service:
// oop := (CheckCastPP init.Control alloc.RawAddress #short[])
// Suppose its body is immediately initialized as {1,2}:
// store1 = (StoreC init.Control init.Memory (+ oop 12) 1)
// store2 = (StoreC init.Control store1 (+ oop 14) 2)
// mem.SLICE(#short[*]) := store2
//
// DETAILS:
// An InitializeNode collects and isolates object initialization after
// an AllocateNode and before the next possible safepoint. As a
// memory barrier (MemBarNode), it keeps critical stores from drifting
// down past any safepoint or any publication of the allocation.
// Before this barrier, a newly-allocated object may have uninitialized bits.
// After this barrier, it may be treated as a real oop, and GC is allowed.
//
// The semantics of the InitializeNode include an implicit zeroing of
// the new object from object header to the end of the object.
// (The object header and end are determined by the AllocateNode.)
//
// Certain stores may be added as direct inputs to the InitializeNode.
// These stores must update raw memory, and they must be to addresses
// derived from the raw address produced by AllocateNode, and with
// a constant offset. They must be ordered by increasing offset.
// The first one is at in(RawStores), the last at in(req()-1).
// Unlike most memory operations, they are not linked in a chain,
// but are displayed in parallel as users of the rawmem output of
// the allocation.
//
// (See comments in InitializeNode::capture_store, which continue
// the example given above.)
//
// When the associated Allocate is macro-expanded, the InitializeNode
// may be rewritten to optimize collected stores. A ClearArrayNode
// may also be created at that point to represent any required zeroing.
// The InitializeNode is then marked 'complete', prohibiting further
// capturing of nearby memory operations.
//
// During macro-expansion, all captured initializations which store
// constant values of 32 bits or smaller are coalesced (if advantageous)
// into larger 'tiles' 32 or 64 bits. This allows an object to be
// initialized in fewer memory operations. Memory words which are
// covered by neither tiles nor non-constant stores are pre-zeroed
// by explicit stores of zero. (The code shape happens to do all
// zeroing first, then all other stores, with both sequences occurring
// in order of ascending offsets.)
//
// Alternatively, code may be inserted between an AllocateNode and its
// InitializeNode, to perform arbitrary initialization of the new object.
// E.g., the object copying intrinsics insert complex data transfers here.
// The initialization must then be marked as 'complete' disable the
// built-in zeroing semantics and the collection of initializing stores.
//
// While an InitializeNode is incomplete, reads from the memory state
// produced by it are optimizable if they match the control edge and
// new oop address associated with the allocation/initialization.
// They return a stored value (if the offset matches) or else zero.
// A write to the memory state, if it matches control and address,
// and if it is to a constant offset, may be 'captured' by the
// InitializeNode. It is cloned as a raw memory operation and rewired
// inside the initialization, to the raw oop produced by the allocation.
// Operations on addresses which are provably distinct (e.g., to
// other AllocateNodes) are allowed to bypass the initialization.
//
// The effect of all this is to consolidate object initialization
// (both arrays and non-arrays, both piecewise and bulk) into a
// single location, where it can be optimized as a unit.
//
// Only stores with an offset less than TrackedInitializationLimit words
// will be considered for capture by an InitializeNode. This puts a
// reasonable limit on the complexity of optimized initializations.
//---------------------------InitializeNode------------------------------------
{
// Note: allocation() can be NULL, for secondary initialization barriers
}
// Since this node is not matched, it will be processed by the
// register allocator. Declare that there are no constraints
// on the allocation of the RawAddress edge.
// This edge should be set to top, by the set_complete. But be conservative.
}
if (mem->is_MergeMem()) {
} else {
// incoming raw memory is not split
return mem;
}
}
if (is_complete()) return false;
}
// After this node is complete, it contains a bunch of
// raw-memory initializations. There is no need for
// it to have anything to do with non-raw memory effects.
// Therefore, tell all non-raw users to re-optimize themselves,
// after skipping the memory effects of this initialization.
}
// convenience function
// return false if the init contains any stores already
// for now, if this allocation has already collected any inits, bail:
if (init->is_non_zero()) return false;
return true;
}
++fill;
}
// delete any empty spaces created:
}
}
// Helper for remembering which stores go with which offsets.
return offset;
}
// Helper for proving that an initialization expression is
// "simple enough" to be folded into an object initialization.
// Attempts to prove that a store's initial value 'n' can be captured
// within the initialization without creating a vicious cycle, such as:
// { Foo p = new Foo(); p.next = p; }
// True for constants and parameters and small combinations thereof.
bool st_is_pinned,
int& count) {
if (n == NULL) return true; // (can this really happen?)
if (n == this) return false; // found a cycle
if (n->is_Con()) return true;
if (n->is_Start()) return true; // params, etc., are OK
if (n->is_Root()) return true; // even better
if (ctl == this) return false;
// If we already know that the enclosing memory op is pinned right after
// the init, then any control flow that the store has picked up
// must have preceded the init, or else be equal to the init.
// Even after loop optimizations (which might change control edges)
// a store is never pinned *before* the availability of its inputs.
if (!MemNode::all_controls_dominate(n, this))
return false; // failed to prove a good control
}
// Check data edges for possible dependencies on 'this'.
if (i != first_i) continue; // process duplicate edge just once
return false;
}
}
return true;
}
// Here are all the checks a Store must pass before it can be moved into
// an initialization. Returns zero if a check fails.
// On success, returns the (constant) offset to which the store applies,
// within the initialized memory.
intptr_t InitializeNode::can_capture_store(StoreNode* st, PhaseTransform* phase, bool can_reshape) {
const int FAIL = 0;
return FAIL; // an inscrutable StoreNode (card mark?)
return FAIL; // must be unconditional after the initialization
return FAIL; // must not be preceded by other stores
return FAIL; // inscrutable address
if (alloc != allocation())
return FAIL; // wrong allocation! (store needs to float up)
int complexity_count = 0;
return FAIL; // stored value must be 'simple enough'
// The Store can be captured only if nothing after the allocation
// and before the Store is using the memory location that the store
// overwrites.
bool failed = false;
// If is_complete_with_arraycopy() is true the shape of the graph is
// well defined and is safe so no need for extra checks.
if (!is_complete_with_arraycopy()) {
// We are going to look at each use of the memory state following
// the allocation to make sure nothing reads the memory that the
// Store writes.
if (n->outcnt() == 0) {
continue;
}
if (n == st) {
continue;
// If the control of this use is different from the control
// of the Store which is right after the InitializeNode then
// this node cannot be between the InitializeNode and the
// Store.
continue;
} else if (n->is_MergeMem()) {
// We can hit a MergeMemNode (that will likely go away
// later) that is a direct use of the memory state
// following the InitializeNode on the same slice as the
// store node that we'd like to capture. We need to check
// the uses of the MergeMemNode.
}
} else if (n->is_Mem()) {
failed = true;
break;
} else {
if (other_t_adr != NULL) {
if (other_alias_idx == alias_idx) {
// A load from the same memory slice as the store right
// after the InitializeNode. We check the control of the
// the store control then we cannot capture the store.
failed = true;
break;
}
}
}
}
}
} else {
failed = true;
break;
}
}
}
}
if (failed) {
if (!can_reshape) {
// We decided we couldn't capture the store during parsing. We
// should try again during the next IGVN once the graph is
// cleaner.
}
return FAIL;
}
return offset; // success
}
// Find the captured store in(i) which corresponds to the range
// [start..start+size) in the initialized object.
// If there is one, return its index i. If there isn't, return the
// negative of the index where it should be inserted.
// Return 0 if the queried range overlaps an initialization boundary
// or if dead code is encountered.
// If size_in_bytes is zero, do not bother with overlap checks.
int size_in_bytes,
PhaseTransform* phase) {
if (is_complete())
return FAIL; // arraycopy got here first; punt
// no negatives, no header fields:
// after a certain size, we bail out on tracking all the stores:
if (i >= limit) return -(int)i; // not found; here is where to put it
if (st_off < 0) {
if (st != zero_memory()) {
return FAIL; // bail out if there is dead garbage
}
// ...we are done, since stores are ordered
return FAIL; // the next store overlaps
}
return -(int)i; // not found; here is where to put it
if (size_in_bytes != 0 &&
return FAIL; // the previous store overlaps
}
} else {
if (size_in_bytes != 0 &&
return FAIL; // mismatched store size
}
return i;
}
++i;
}
}
// Look for a captured store which initializes at the offset 'start'
// with the given size. If there is no such store, and no other
// initialization interferes, then return zero_memory (the memory
// projection of the AllocateNode).
PhaseTransform* phase) {
if (i == 0) {
return NULL; // something is dead
} else if (i < 0) {
return zero_memory(); // just primordial zero bits here
} else {
return st;
}
}
// Create, as a raw pointer, an address within my new object at 'offset'.
PhaseTransform* phase) {
if (offset != 0) {
}
return addr;
}
// Clone the given store, converting it into a raw store
// initializing a field or element of my new object.
// Caller is responsible for retiring the original store,
// with subsume_node or the like.
//
// From the example above InitializeNode::InitializeNode,
// here are the old stores to be captured:
// store1 = (StoreC init.Control init.Memory (+ oop 12) 1)
// store2 = (StoreC init.Control store1 (+ oop 14) 2)
//
// Here is the changed code; note the extra edges on init:
// alloc = (Allocate ...)
// rawoop = alloc.RawAddress
// rawstore1 = (StoreC alloc.Control alloc.Memory (+ rawoop 12) 1)
// rawstore2 = (StoreC alloc.Control alloc.Memory (+ rawoop 14) 2)
// init = (Initialize alloc.Control alloc.Memory rawoop
// rawstore1 rawstore2)
//
if (i == 0) return NULL; // bail out
if (i > 0) {
// See StoreNode::Ideal 'st->outcnt() == 1' for the reason to disconnect.
} else {
i = -i; // no pre-existing store
else
}
// At this point, new_st might have swallowed a pre-existing store
// at the same offset, or perhaps new_st might have disappeared,
// if it redundantly stored the same value (or zero to fresh memory).
// In any case, wire it in:
// The caller may now kill the old guy.
return new_st;
}
return false; // strange store offset (assume size==2**N)
switch (st_size) {
default: return false; // strange store size (detect size!=2**N here)
}
return true; // return success to caller
}
// Coalesce subword constants into int constants and possibly
// into long constants. The goal, if the CPU permits,
// is to initialize the object with a small number of 64-bit tiles.
// Also, convert floating-point constants to bit patterns.
// Non-constants are not relevant to this pass.
//
// In terms of the running example on InitializeNode::InitializeNode
// and InitializeNode::capture_store, here is the transformation
// of rawstore1 and rawstore2 into rawstore12:
// alloc = (Allocate ...)
// rawoop = alloc.RawAddress
// tile12 = 0x00010002
// rawstore12 = (StoreI alloc.Control alloc.Memory (+ rawoop 12) tile12)
// init = (Initialize alloc.Control alloc.Memory rawoop rawstore12)
//
void
// Note: After this pass, they are not completely sane,
// since there may be some overlaps.
// allocate space for the tile map:
// tiles: exact bitwise model of all primitive constants
// nodes: last constant-storing node subsumed into the tiles model
// inits: which bytes (in each tile) are touched by any initializations
//// Pass A: Fill in the tile model with any relevant stores.
// Figure out the store's offset and constant value:
// Record which bytes are touched, whether by constant or not.
continue; // skip (strange store size)
switch (type) {
default: continue; //skip (odd store type)
}
continue; // This StoreL is already optimal.
}
// Store down the constant.
// This StoreI is already optimal by itself.
// If the previous store is also optimal by itself, back up and
// undo the action of the previous loop iteration... if we can.
// But if we can't, just let the previous half take care of itself.
st_off -= BytesPerInt;
// Undo the effects of the previous loop trip, which swallowed st:
intcon[0] = 0; // undo store_constant()
--old_subword; // undo ++old_subword
}
continue; // This StoreI is already optimal.
}
}
// This store is not needed.
++old_subword; // includes int/float, but who's counting...
else ++old_long;
}
if ((old_subword + old_long) == 0)
return; // nothing more to do
//// Pass B: Convert any non-zero tiles into optimal constant stores.
// Be sure to insert them before overlapping non-constant stores.
// (E.g., byte[] x = { 1,2,y,4 } => x[int 0] = 0x01020004, x[2]=y.)
for (int j = 0; j < num_tiles; j++) {
if (con == 0) continue;
}
if (offset < header_size) {
split = true; // only the second word counts
// Example: int a[] = { 42 ... }
split = true; // first word is covered by full inits
// Example: int a[] = { ... foo(), 42 ... }
split = true; // second word is covered by full inits
// Example: int a[] = { ... 42, foo() ... }
}
// Here's a case where init0 is neither 0 nor -1:
// byte a[] = { ... 0,0,foo(),0, 0,0,0,42 ... }
// Assuming big-endian memory, init0, init1 are 0x0000FF00, 0x000000FF.
// In this case the tile is not split; it is (jlong)42.
// The big tile is stored down, and then the foo() value is inserted.
// (If there were foo(),foo() instead of foo(),0, init0 would be -1.)
// One or two coalesced stores to plop down.
int nst = 0;
if (!split) {
++new_long;
} else {
// Omit either if it is a zero.
if (con0 != 0) {
++new_int;
}
if (con1 != 0) {
++new_int;
offset += BytesPerInt;
}
}
// Insert second store first, then the first before the second.
// Insert each one just before any overlapping non-constant stores.
while (nst > 0) {
else
}
}
if (PrintCompilation && WizardMode)
// Clean up any remaining occurrences of zmem:
}
// Explore forward from in(start) to find the first fully initialized
// word, and return its offset. Skip groups of subword stores which
// together initialize full words. If in(start) is itself part of a
// fully initialized word, return the offset of in(start). If there
// are no following full-word stores, or if something is fishy, return
// a negative value.
int int_map = 0;
if (st_off < 0) break; // return conservative answer
return st_off; // we found a complete word init
}
// update the map:
if (this_int_off != int_map_off) {
// reset the map:
int_map = 0;
}
return this_int_off; // we found a complete word init
}
// Did this store hit or cross the word boundary?
// We passed the current int, without fully initializing it.
// We passed the current and next int.
return this_int_off + BytesPerInt;
}
}
return -1;
}
// Called when the associated AllocateNode is expanded into CFG.
// At this point, we may perform additional optimizations.
// Linearize the stores by ascending offset, to make memory
// activity as coherent as possible.
if (ReduceFieldZeroing || ReduceBulkZeroing)
// reduce instruction count for common initialization patterns
#ifdef ASSERT
#endif
if (ZeroTLAB) do_zeroing = false;
if (st_off < 0)
break; // unknown junk in the inits
break; // complicated store chains somehow in list
// See if this store needs a zero before it or under it.
if (st_size < BytesPerInt) {
// Look for subword stores which only partially initialize words.
// If we find some, we must lay down some word-level zeroes first,
// underneath the subword stores.
//
// Examples:
// byte[] a = { p,q,r,s } => a[0]=p,a[1]=q,a[2]=r,a[3]=s
// byte[] a = { x,y,0,0 } => a[0..3] = 0, a[0]=x,a[1]=y
// byte[] a = { 0,0,z,0 } => a[0..3] = 0, a[2]=z
//
// Note: coalesce_subword_stores may have already done this,
// if it was prompted by constant non-zero subword initializers.
// But this case can still arise with non-constant stores.
// In the examples above:
// in(i) p q r s x y z
// st_off 12 13 14 15 12 13 14
// st_size 1 1 1 1 1 1 1
// next_full_s. 12 16 16 16 16 16 16
// z's_done 12 16 16 16 12 16 12
// z's_needed 12 16 16 16 16 16 16
// zsize 0 0 0 0 4 0 4
if (next_full_store < 0) {
// Conservative tack: Zero to end of current word.
} else {
// Zero to beginning of next fully initialized word.
// Or, don't zero at all, if we are already in that word.
}
}
if (zeroes_needed > zeroes_done) {
// Do some incremental zeroing on rawmem, in parallel with inits.
phase);
do_zeroing = false; // leave the hole, next time
}
}
// Collect the store and move on:
if (zeroes_done == st_off)
#ifdef ASSERT
// Various order invariants. Weaker than stores_are_sane because
// a large constant tile can be filled in by smaller non-constant stores.
if (st_size >= BytesPerInt &&
} else {
}
#endif //ASSERT
}
remove_extra_zeroes(); // clear out all the zmems left over
if (!ZeroTLAB) {
// If anything remains to be zeroed, zero it all now.
// if it is the last unused 4 bytes of an instance, forget about it
if (zeroes_done == k->layout_helper())
}
}
if (zeroes_done < size_limit) {
}
}
return rawmem;
}
#ifdef ASSERT
if (is_complete())
return true; // stores could be anything at this point
if (st_off < 0) continue; // ignore dead garbage
this->dump(2);
assert(false, "ascending store offsets");
return false;
}
}
return true;
}
#endif //ASSERT
//============================MergeMemNode=====================================
//
// SEMANTICS OF MEMORY MERGES: A MergeMem is a memory state assembled from several
// contributing store or call operations. Each contributor provides the memory
// state for a particular "alias type" (see Compile::alias_type). For example,
// if a MergeMem has an input X for alias category #6, then any memory reference
// to alias category #6 may use X as its memory state input, as an exact equivalent
// to using the MergeMem as a whole.
// Load<6>( MergeMem(<6>: X, ...), p ) <==> Load<6>(X,p)
//
// (Here, the <N> notation gives the index of the relevant adr_type.)
//
// In one special case (and more cases in the future), alias categories overlap.
// The special alias category "Bot" (Compile::AliasIdxBot) includes all memory
// states. Therefore, if a MergeMem has only one contributing input W for Bot,
// it is exactly equivalent to that state W:
// MergeMem(<Bot>: W) <==> W
//
// Usually, the merge has more than one input. In that case, where inputs
// overlap (i.e., one is Bot), the narrower alias type determines the memory
// state for that type, and the wider alias type (Bot) fills in everywhere else:
// Load<5>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<5>(W,p)
// Load<6>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<6>(X,p)
//
// A merge can take a "wide" memory state as one of its narrow inputs.
// This simply means that the merge observes out only the relevant parts of
// the wide input. That is, wide memory states arriving at narrow merge inputs
// are implicitly "filtered" or "sliced" as necessary. (This is rare.)
//
// These rules imply that MergeMem nodes may cascade (via their <Bot> links),
// and that memory slices "leak through":
// MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y)) <==> MergeMem(<Bot>: W, <7>: Y)
//
// But, in such a cascade, repeated memory slices can "block the leak":
// MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y), <7>: Y') <==> MergeMem(<Bot>: W, <7>: Y')
//
// In the last example, Y is not part of the combined memory state of the
// outermost MergeMem. The system must, of course, prevent unschedulable
// memory states from arising, so you can be sure that the state Y is somehow
// a precursor to state Y'.
//
//
// REPRESENTATION OF MEMORY MERGES: The indexes used to address the Node::in array
// of each MergeMemNode array are exactly the numerical alias indexes, including
// but not limited to AliasIdxTop, AliasIdxBot, and AliasIdxRaw. The functions
// Compile::alias_type (and kin) produce and manage these indexes.
//
// By convention, the value of in(AliasIdxTop) (i.e., in(1)) is always the top node.
// (Note that this provides quick access to the top node inside MergeMem methods,
// without the need to reach out via TLS to Compile::current.)
//
// As a consequence of what was just described, a MergeMem that represents a full
// memory state has an edge in(AliasIdxBot) which is a "wide" memory state,
// containing all alias categories.
//
// MergeMem nodes never (?) have control inputs, so in(0) is NULL.
//
// All other edges in(N) (including in(AliasIdxRaw), which is in(3)) are either
// a memory state for the alias type <N>, or else the top node, meaning that
// there is no particular input for that alias type. Note that the length of
// a MergeMem is variable, and may be extended at any time to accommodate new
// memory states at larger alias indexes. When merges grow, they are of course
// filled with "top" in the unused in() positions.
//
// This use of top is named "empty_memory()", or "empty_mem" (no-memory) as a variable.
// (Top was chosen because it works smoothly with passes like GCM.)
//
// For convenience, we hardwire the alias index for TypeRawPtr::BOTTOM. (It is
// the type of random VM bits like TLS references.) Since it is always the
// first non-Bot memory slice, some low-level loops use it to initialize an
// index variable: for (i = AliasIdxRaw; i < req(); i++).
//
//
// ACCESSORS: There is a special accessor MergeMemNode::base_memory which returns
// the distinguished "wide" state. The accessor MergeMemNode::memory_at(N) returns
// the memory state for alias type <N>, or (if there is no particular slice at <N>,
// it returns the base memory. To prevent bugs, memory_at does not accept <Top>
// or <Bot> indexes. The iterator MergeMemStream provides robust iteration over
// MergeMem nodes or pairs of such nodes, ensuring that the non-top edges are visited.
//
// %%%% We may get rid of base_memory as a separate accessor at some point; it isn't
// really that different from the other memory inputs. An abbreviation called
// "bot_memory()" for "memory_at(AliasIdxBot)" would keep code tidy.
//
//
// PARTIAL MEMORY STATES: During optimization, MergeMem nodes may arise that represent
// partial memory states. When a Phi splits through a MergeMem, the copy of the Phi
// that "emerges though" the base memory will be marked as excluding the alias types
// of the other (narrow-memory) copies which "emerged through" the narrow edges:
//
// Phi<Bot>(U, MergeMem(<Bot>: W, <8>: Y))
// ==Ideal=> MergeMem(<Bot>: Phi<Bot-8>(U, W), Phi<8>(U, Y))
//
// This strange "subtraction" effect is necessary to ensure IGVN convergence.
// (It is currently unimplemented.) As you can see, the resulting merge is
// actually a disjoint union of memory states, rather than an overlay.
//
//------------------------------MergeMemNode-----------------------------------
return empty_memory;
}
// all inputs are nullified in Node::Node(int)
// set_input(0, NULL); // no control input
// Initialize the edges uniformly to top, for starters.
}
}
} else {
}
}
// Make a new, untransformed MergeMem with the same base as 'mem'.
// If mem is itself a MergeMem, populate the result with the same edges.
return new(C) MergeMemNode(mem);
}
//------------------------------cmp--------------------------------------------
return (&n == this); // Always fail except on self
}
//------------------------------Identity---------------------------------------
// Identity if this merge point does not record any interesting memory
// disambiguations.
return this; // Many memory splits; no change
}
}
}
return base_mem; // No memory splits; ID on the one true input
}
//------------------------------Ideal------------------------------------------
// This method is invoked recursively on chains of MergeMem nodes
// Remove chain'd MergeMems
//
// This is delicate, because the each "in(i)" (i >= Raw) is interpreted
// relative to the "in(Bot)". Since we are patching both at the same time,
// we have to be careful to read each "in(i)" relative to the old "in(Bot)",
// but rewrite each "in(i)" relative to the new "in(Bot)".
return NULL; // Dead memory path.
else
// simplify stacked MergeMems in base memory
// the base memory might contribute new slices beyond my req()
// Look carefully at the base node if it is a phi.
else
// do not examine phi if degraded to a copy
// see if the phi is unfinished
// incomplete phi; do not look at it yet!
break;
}
}
}
// Note: We do not call verify_sparse on entry, because inputs
// can normalize to the base_memory via subsume_node or similar
// mechanisms. This method repairs that damage.
// Look at each slice.
// calculate the old memory value
// maybe update (reslice) the old memory value
// simplify stacked MergeMems
else
if (old_mmem == this) {
// This can happen if loops break up and safepoints disappear.
// A merge of BotPtr (default) with a RawPtr memory derived from a
// safepoint can be rewritten to a merge of the same BotPtr with
// the BotPtr phi coming into the loop. If that phi disappears
// also, we can end up with a self-loop of the mergemem.
// In general, if loops degenerate and memory effects disappear,
// a mergemem can be left looking at itself. This simply means
// that the mergemem's default should be used, since there is
// no longer any apparent effect on this slice.
// Note: If a memory slice is a MergeMem cycle, it is unreachable
// from start. Update the input to TOP.
}
}
// else preceding memory was not a MergeMem
// replace equivalent phis (unfortunately, they do not GVN together)
break;
}
}
// equivalent phi nodes; revert to the def
}
}
}
// maybe store down a new value
// Warning: Do not combine this "if" with the previous "if"
// A memory slice might have be be rewritten even if it is semantically
// unchanged, if the base_memory value has changed.
progress = this; // Report progress
}
}
// Don't use set_base_memory(new_base), because we need to update du.
progress = this;
}
if( base_memory() == this ) {
// a self cycle indicates this memory path is dead
}
// Resolve external cycles by calling Ideal on a MergeMem base_memory
// Recursion must occur after the self cycle check above
if( base_memory()->is_MergeMem() ) {
// propagate rollup of dead cycle to self
}
}
if( base_memory() == empty_mem ) {
progress = this;
// Cut inputs during Parse phase only.
// During Optimize phase a dead MergeMem node will be subsumed by Top.
if( !can_reshape ) {
}
}
}
// Check if PhiNode::Ideal's "Split phis through memory merges"
// transform should be attempted. Look for this->phi->this cycle.
break;
}
}
}
}
return progress;
}
//-------------------------set_base_memory-------------------------------------
// Clear out other occurrences of new_base:
}
}
}
//------------------------------out_RegMask------------------------------------
}
//------------------------------dump_spec--------------------------------------
#ifndef PRODUCT
}
}
#endif // !PRODUCT
#ifdef ASSERT
if (a == b) return true;
// phis shift around during optimization
return true; // pretty stupid...
}
// verify a narrow slice (either incoming or outgoing)
if (!VerifyAliases) return; // don't bother to verify unless requested
if (is_error_reported()) return; // muzzle asserts when debugging an error
// Elide intervening MergeMem's
while (n->is_MergeMem()) {
}
if (n == m->empty_memory()) {
// Implicit copy of base_memory()
} else {
// A few places like make_runtime_call "know" that VM calls are narrow,
// and can be used to update only the VM bits stored as TypeRawPtr::BOTTOM.
bool expected_wide_mem = false;
if (n == m->base_memory()) {
expected_wide_mem = true;
expected_wide_mem = true;
// memory can "leak through" calls on channels that
// are write-once. Allow this also.
expected_wide_mem = true;
}
}
}
#else // !ASSERT
#endif
//-----------------------------memory_at---------------------------------------
"must avoid base_memory and AliasIdxTop");
// Otherwise, it is a narrow slice.
if (is_empty_memory(n)) {
// the array is sparse; empty slots are the "top" node
n = base_memory();
"must be a wide memory");
// AliasLevel == 0 if we are organizing the memory states manually.
// See verify_memory_slice for comments on TypeRawPtr::BOTTOM.
} else {
// make sure the stored slice is sane
#ifdef ASSERT
} else if (might_be_same(n, base_memory())) {
// Give it a pass: It is a mostly harmless repetition of the base.
// This can arise normally from node subsumption during optimization.
} else {
verify_memory_slice(this, alias_idx, n);
}
#endif
}
return n;
}
//---------------------------set_memory_at-------------------------------------
verify_memory_slice(this, alias_idx, n);
if (n == empty_mem) return; // already the default, so do not grow me
// grow the sparse array
do {
}
}
//--------------------------iteration_setup------------------------------------
// invariant: the finite support of mm2 is within mm->req()
#ifdef ASSERT
}
#endif
}
// Replace spurious copies of base_memory by top.
set_req(i, empty_memory());
}
}
}
//---------------------------grow_to_match-------------------------------------
// look for the finite support of the other memory
break;
}
}
}
//---------------------------verify_sparse-------------------------------------
#ifndef PRODUCT
bool MergeMemNode::verify_sparse() const {
// The following can happen in degenerate cases, since empty==top.
if (is_empty_memory(base_mem)) return true;
}
return true;
}
Node* n;
if (mem == n) return true; // might be empty_memory()
if (mem == n) return true;
if (mem == n) return true;
if (n == NULL) break;
}
return false;
}
#endif // !PRODUCT