/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "ssa_builder.h"
#include "bytecode_utils.h"
#include "nodes.h"
#include "reference_type_propagation.h"
#include "ssa_phi_elimination.h"
namespace art {
void SsaBuilder::FixNullConstantType() {
// The order doesn't matter here.
for (HReversePostOrderIterator itb(*graph_); !itb.Done(); itb.Advance()) {
for (HInstructionIterator it(itb.Current()->GetInstructions()); !it.Done(); it.Advance()) {
HInstruction* equality_instr = it.Current();
if (!equality_instr->IsEqual() && !equality_instr->IsNotEqual()) {
continue;
}
HInstruction* left = equality_instr->InputAt(0);
HInstruction* right = equality_instr->InputAt(1);
HInstruction* int_operand = nullptr;
if ((left->GetType() == Primitive::kPrimNot) && (right->GetType() == Primitive::kPrimInt)) {
int_operand = right;
} else if ((right->GetType() == Primitive::kPrimNot)
&& (left->GetType() == Primitive::kPrimInt)) {
int_operand = left;
} else {
continue;
}
// If we got here, we are comparing against a reference and the int constant
// should be replaced with a null constant.
// Both type propagation and redundant phi elimination ensure `int_operand`
// can only be the 0 constant.
DCHECK(int_operand->IsIntConstant()) << int_operand->DebugName();
DCHECK_EQ(0, int_operand->AsIntConstant()->GetValue());
equality_instr->ReplaceInput(graph_->GetNullConstant(), int_operand == right ? 1 : 0);
}
}
}
void SsaBuilder::EquivalentPhisCleanup() {
// The order doesn't matter here.
for (HReversePostOrderIterator itb(*graph_); !itb.Done(); itb.Advance()) {
for (HInstructionIterator it(itb.Current()->GetPhis()); !it.Done(); it.Advance()) {
HPhi* phi = it.Current()->AsPhi();
HPhi* next = phi->GetNextEquivalentPhiWithSameType();
if (next != nullptr) {
// Make sure we do not replace a live phi with a dead phi. A live phi
// has been handled by the type propagation phase, unlike a dead phi.
if (next->IsLive()) {
phi->ReplaceWith(next);
phi->SetDead();
} else {
next->ReplaceWith(phi);
}
DCHECK(next->GetNextEquivalentPhiWithSameType() == nullptr)
<< "More then one phi equivalent with type " << phi->GetType()
<< " found for phi" << phi->GetId();
}
}
}
}
void SsaBuilder::FixEnvironmentPhis() {
for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) {
HBasicBlock* block = it.Current();
for (HInstructionIterator it_phis(block->GetPhis()); !it_phis.Done(); it_phis.Advance()) {
HPhi* phi = it_phis.Current()->AsPhi();
// If the phi is not dead, or has no environment uses, there is nothing to do.
if (!phi->IsDead() || !phi->HasEnvironmentUses()) continue;
HInstruction* next = phi->GetNext();
if (!phi->IsVRegEquivalentOf(next)) continue;
if (next->AsPhi()->IsDead()) {
// If the phi equivalent is dead, check if there is another one.
next = next->GetNext();
if (!phi->IsVRegEquivalentOf(next)) continue;
// There can be at most two phi equivalents.
DCHECK(!phi->IsVRegEquivalentOf(next->GetNext()));
if (next->AsPhi()->IsDead()) continue;
}
// We found a live phi equivalent. Update the environment uses of `phi` with it.
phi->ReplaceWith(next);
}
}
}
static void AddDependentInstructionsToWorklist(HInstruction* instruction,
ArenaVector<HPhi*>* worklist) {
// If `instruction` is a dead phi, type conflict was just identified. All its
// live phi users, and transitively users of those users, therefore need to be
// marked dead/conflicting too, so we add them to the worklist. Otherwise we
// add users whose type does not match and needs to be updated.
bool add_all_live_phis = instruction->IsPhi() && instruction->AsPhi()->IsDead();
for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) {
HInstruction* user = use.GetUser();
if (user->IsPhi() && user->AsPhi()->IsLive()) {
if (add_all_live_phis || user->GetType() != instruction->GetType()) {
worklist->push_back(user->AsPhi());
}
}
}
}
// Find a candidate primitive type for `phi` by merging the type of its inputs.
// Return false if conflict is identified.
static bool TypePhiFromInputs(HPhi* phi) {
Primitive::Type common_type = phi->GetType();
for (HInputIterator it(phi); !it.Done(); it.Advance()) {
HInstruction* input = it.Current();
if (input->IsPhi() && input->AsPhi()->IsDead()) {
// Phis are constructed live so if an input is a dead phi, it must have
// been made dead due to type conflict. Mark this phi conflicting too.
return false;
}
Primitive::Type input_type = HPhi::ToPhiType(input->GetType());
if (common_type == input_type) {
// No change in type.
} else if (Primitive::Is64BitType(common_type) != Primitive::Is64BitType(input_type)) {
// Types are of different sizes, e.g. int vs. long. Must be a conflict.
return false;
} else if (Primitive::IsIntegralType(common_type)) {
// Previous inputs were integral, this one is not but is of the same size.
// This does not imply conflict since some bytecode instruction types are
// ambiguous. TypeInputsOfPhi will either type them or detect a conflict.
DCHECK(Primitive::IsFloatingPointType(input_type) || input_type == Primitive::kPrimNot);
common_type = input_type;
} else if (Primitive::IsIntegralType(input_type)) {
// Input is integral, common type is not. Same as in the previous case, if
// there is a conflict, it will be detected during TypeInputsOfPhi.
DCHECK(Primitive::IsFloatingPointType(common_type) || common_type == Primitive::kPrimNot);
} else {
// Combining float and reference types. Clearly a conflict.
DCHECK((common_type == Primitive::kPrimFloat && input_type == Primitive::kPrimNot) ||
(common_type == Primitive::kPrimNot && input_type == Primitive::kPrimFloat));
return false;
}
}
// We have found a candidate type for the phi. Set it and return true. We may
// still discover conflict whilst typing the individual inputs in TypeInputsOfPhi.
phi->SetType(common_type);
return true;
}
// Replace inputs of `phi` to match its type. Return false if conflict is identified.
bool SsaBuilder::TypeInputsOfPhi(HPhi* phi, ArenaVector<HPhi*>* worklist) {
Primitive::Type common_type = phi->GetType();
if (common_type == Primitive::kPrimVoid || Primitive::IsIntegralType(common_type)) {
// Phi either contains only other untyped phis (common_type == kPrimVoid),
// or `common_type` is integral and we do not need to retype ambiguous inputs
// because they are always constructed with the integral type candidate.
if (kIsDebugBuild) {
for (size_t i = 0, e = phi->InputCount(); i < e; ++i) {
HInstruction* input = phi->InputAt(i);
if (common_type == Primitive::kPrimVoid) {
DCHECK(input->IsPhi() && input->GetType() == Primitive::kPrimVoid);
} else {
DCHECK((input->IsPhi() && input->GetType() == Primitive::kPrimVoid) ||
HPhi::ToPhiType(input->GetType()) == common_type);
}
}
}
// Inputs did not need to be replaced, hence no conflict. Report success.
return true;
} else {
DCHECK(common_type == Primitive::kPrimNot || Primitive::IsFloatingPointType(common_type));
for (size_t i = 0, e = phi->InputCount(); i < e; ++i) {
HInstruction* input = phi->InputAt(i);
if (input->GetType() != common_type) {
// Input type does not match phi's type. Try to retype the input or
// generate a suitably typed equivalent.
HInstruction* equivalent = (common_type == Primitive::kPrimNot)
? GetReferenceTypeEquivalent(input)
: GetFloatOrDoubleEquivalent(input, common_type);
if (equivalent == nullptr) {
// Input could not be typed. Report conflict.
return false;
}
// Make sure the input did not change its type and we do not need to
// update its users.
DCHECK_NE(input, equivalent);
phi->ReplaceInput(equivalent, i);
if (equivalent->IsPhi()) {
worklist->push_back(equivalent->AsPhi());
}
}
}
// All inputs either matched the type of the phi or we successfully replaced
// them with a suitable equivalent. Report success.
return true;
}
}
// Attempt to set the primitive type of `phi` to match its inputs. Return whether
// it was changed by the algorithm or not.
bool SsaBuilder::UpdatePrimitiveType(HPhi* phi, ArenaVector<HPhi*>* worklist) {
DCHECK(phi->IsLive());
Primitive::Type original_type = phi->GetType();
// Try to type the phi in two stages:
// (1) find a candidate type for the phi by merging types of all its inputs,
// (2) try to type the phi's inputs to that candidate type.
// Either of these stages may detect a type conflict and fail, in which case
// we immediately abort.
if (!TypePhiFromInputs(phi) || !TypeInputsOfPhi(phi, worklist)) {
// Conflict detected. Mark the phi dead and return true because it changed.
phi->SetDead();
return true;
}
// Return true if the type of the phi has changed.
return phi->GetType() != original_type;
}
void SsaBuilder::RunPrimitiveTypePropagation() {
ArenaVector<HPhi*> worklist(graph_->GetArena()->Adapter(kArenaAllocGraphBuilder));
for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) {
HBasicBlock* block = it.Current();
if (block->IsLoopHeader()) {
for (HInstructionIterator phi_it(block->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
HPhi* phi = phi_it.Current()->AsPhi();
if (phi->IsLive()) {
worklist.push_back(phi);
}
}
} else {
for (HInstructionIterator phi_it(block->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
// Eagerly compute the type of the phi, for quicker convergence. Note
// that we don't need to add users to the worklist because we are
// doing a reverse post-order visit, therefore either the phi users are
// non-loop phi and will be visited later in the visit, or are loop-phis,
// and they are already in the work list.
HPhi* phi = phi_it.Current()->AsPhi();
if (phi->IsLive()) {
UpdatePrimitiveType(phi, &worklist);
}
}
}
}
ProcessPrimitiveTypePropagationWorklist(&worklist);
EquivalentPhisCleanup();
}
void SsaBuilder::ProcessPrimitiveTypePropagationWorklist(ArenaVector<HPhi*>* worklist) {
// Process worklist
while (!worklist->empty()) {
HPhi* phi = worklist->back();
worklist->pop_back();
// The phi could have been made dead as a result of conflicts while in the
// worklist. If it is now dead, there is no point in updating its type.
if (phi->IsLive() && UpdatePrimitiveType(phi, worklist)) {
AddDependentInstructionsToWorklist(phi, worklist);
}
}
}
static HArrayGet* FindFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) {
Primitive::Type type = aget->GetType();
DCHECK(Primitive::IsIntOrLongType(type));
HInstruction* next = aget->GetNext();
if (next != nullptr && next->IsArrayGet()) {
HArrayGet* next_aget = next->AsArrayGet();
if (next_aget->IsEquivalentOf(aget)) {
return next_aget;
}
}
return nullptr;
}
static HArrayGet* CreateFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) {
Primitive::Type type = aget->GetType();
DCHECK(Primitive::IsIntOrLongType(type));
DCHECK(FindFloatOrDoubleEquivalentOfArrayGet(aget) == nullptr);
HArrayGet* equivalent = new (aget->GetBlock()->GetGraph()->GetArena()) HArrayGet(
aget->GetArray(),
aget->GetIndex(),
type == Primitive::kPrimInt ? Primitive::kPrimFloat : Primitive::kPrimDouble,
aget->GetDexPc());
aget->GetBlock()->InsertInstructionAfter(equivalent, aget);
return equivalent;
}
static Primitive::Type GetPrimitiveArrayComponentType(HInstruction* array)
SHARED_REQUIRES(Locks::mutator_lock_) {
ReferenceTypeInfo array_type = array->GetReferenceTypeInfo();
DCHECK(array_type.IsPrimitiveArrayClass());
return array_type.GetTypeHandle()->GetComponentType()->GetPrimitiveType();
}
bool SsaBuilder::FixAmbiguousArrayOps() {
if (ambiguous_agets_.empty() && ambiguous_asets_.empty()) {
return true;
}
// The wrong ArrayGet equivalent may still have Phi uses coming from ArraySet
// uses (because they are untyped) and environment uses (if --debuggable).
// After resolving all ambiguous ArrayGets, we will re-run primitive type
// propagation on the Phis which need to be updated.
ArenaVector<HPhi*> worklist(graph_->GetArena()->Adapter(kArenaAllocGraphBuilder));
{
ScopedObjectAccess soa(Thread::Current());
for (HArrayGet* aget_int : ambiguous_agets_) {
HInstruction* array = aget_int->GetArray();
if (!array->GetReferenceTypeInfo().IsPrimitiveArrayClass()) {
// RTP did not type the input array. Bail.
return false;
}
HArrayGet* aget_float = FindFloatOrDoubleEquivalentOfArrayGet(aget_int);
Primitive::Type array_type = GetPrimitiveArrayComponentType(array);
DCHECK_EQ(Primitive::Is64BitType(aget_int->GetType()), Primitive::Is64BitType(array_type));
if (Primitive::IsIntOrLongType(array_type)) {
if (aget_float != nullptr) {
// There is a float/double equivalent. We must replace it and re-run
// primitive type propagation on all dependent instructions.
aget_float->ReplaceWith(aget_int);
aget_float->GetBlock()->RemoveInstruction(aget_float);
AddDependentInstructionsToWorklist(aget_int, &worklist);
}
} else {
DCHECK(Primitive::IsFloatingPointType(array_type));
if (aget_float == nullptr) {
// This is a float/double ArrayGet but there were no typed uses which
// would create the typed equivalent. Create it now.
aget_float = CreateFloatOrDoubleEquivalentOfArrayGet(aget_int);
}
// Replace the original int/long instruction. Note that it may have phi
// uses, environment uses, as well as real uses (from untyped ArraySets).
// We need to re-run primitive type propagation on its dependent instructions.
aget_int->ReplaceWith(aget_float);
aget_int->GetBlock()->RemoveInstruction(aget_int);
AddDependentInstructionsToWorklist(aget_float, &worklist);
}
}
// Set a flag stating that types of ArrayGets have been resolved. Requesting
// equivalent of the wrong type with GetFloatOrDoubleEquivalentOfArrayGet
// will fail from now on.
agets_fixed_ = true;
for (HArraySet* aset : ambiguous_asets_) {
HInstruction* array = aset->GetArray();
if (!array->GetReferenceTypeInfo().IsPrimitiveArrayClass()) {
// RTP did not type the input array. Bail.
return false;
}
HInstruction* value = aset->GetValue();
Primitive::Type value_type = value->GetType();
Primitive::Type array_type = GetPrimitiveArrayComponentType(array);
DCHECK_EQ(Primitive::Is64BitType(value_type), Primitive::Is64BitType(array_type));
if (Primitive::IsFloatingPointType(array_type)) {
if (!Primitive::IsFloatingPointType(value_type)) {
DCHECK(Primitive::IsIntegralType(value_type));
// Array elements are floating-point but the value has not been replaced
// with its floating-point equivalent. The replacement must always
// succeed in code validated by the verifier.
HInstruction* equivalent = GetFloatOrDoubleEquivalent(value, array_type);
DCHECK(equivalent != nullptr);
aset->ReplaceInput(equivalent, /* input_index */ 2);
if (equivalent->IsPhi()) {
// Returned equivalent is a phi which may not have had its inputs
// replaced yet. We need to run primitive type propagation on it.
worklist.push_back(equivalent->AsPhi());
}
}
} else {
// Array elements are integral and the value assigned to it initially
// was integral too. Nothing to do.
DCHECK(Primitive::IsIntegralType(array_type));
DCHECK(Primitive::IsIntegralType(value_type));
}
}
}
if (!worklist.empty()) {
ProcessPrimitiveTypePropagationWorklist(&worklist);
EquivalentPhisCleanup();
}
return true;
}
static bool HasAliasInEnvironments(HInstruction* instruction) {
HEnvironment* last_user = nullptr;
for (const HUseListNode<HEnvironment*>& use : instruction->GetEnvUses()) {
DCHECK(use.GetUser() != nullptr);
// Note: The first comparison (== null) always fails.
if (use.GetUser() == last_user) {
return true;
}
last_user = use.GetUser();
}
if (kIsDebugBuild) {
// Do a quadratic search to ensure same environment uses are next
// to each other.
const HUseList<HEnvironment*>& env_uses = instruction->GetEnvUses();
for (auto current = env_uses.begin(), end = env_uses.end(); current != end; ++current) {
auto next = current;
for (++next; next != end; ++next) {
DCHECK(next->GetUser() != current->GetUser());
}
}
}
return false;
}
void SsaBuilder::RemoveRedundantUninitializedStrings() {
if (graph_->IsDebuggable()) {
// Do not perform the optimization for consistency with the interpreter
// which always allocates an object for new-instance of String.
return;
}
for (HNewInstance* new_instance : uninitialized_strings_) {
DCHECK(new_instance->IsInBlock());
DCHECK(new_instance->IsStringAlloc());
// Replace NewInstance of String with NullConstant if not used prior to
// calling StringFactory. In case of deoptimization, the interpreter is
// expected to skip null check on the `this` argument of the StringFactory call.
if (!new_instance->HasNonEnvironmentUses() && !HasAliasInEnvironments(new_instance)) {
new_instance->ReplaceWith(graph_->GetNullConstant());
new_instance->GetBlock()->RemoveInstruction(new_instance);
// Remove LoadClass if not needed any more.
HInstruction* input = new_instance->InputAt(0);
HLoadClass* load_class = nullptr;
// If the class was not present in the dex cache at the point of building
// the graph, the builder inserted a HClinitCheck in between. Since the String
// class is always initialized at the point of running Java code, we can remove
// that check.
if (input->IsClinitCheck()) {
load_class = input->InputAt(0)->AsLoadClass();
input->ReplaceWith(load_class);
input->GetBlock()->RemoveInstruction(input);
} else {
load_class = input->AsLoadClass();
DCHECK(new_instance->IsStringAlloc());
DCHECK(!load_class->NeedsAccessCheck()) << "String class is always accessible";
}
DCHECK(load_class != nullptr);
if (!load_class->HasUses()) {
// Even if the HLoadClass needs access check, we can remove it, as we know the
// String class does not need it.
load_class->GetBlock()->RemoveInstruction(load_class);
}
}
}
}
GraphAnalysisResult SsaBuilder::BuildSsa() {
DCHECK(!graph_->IsInSsaForm());
// 1) Propagate types of phis. At this point, phis are typed void in the general
// case, or float/double/reference if we created an equivalent phi. So we need
// to propagate the types across phis to give them a correct type. If a type
// conflict is detected in this stage, the phi is marked dead.
RunPrimitiveTypePropagation();
// 2) Now that the correct primitive types have been assigned, we can get rid
// of redundant phis. Note that we cannot do this phase before type propagation,
// otherwise we could get rid of phi equivalents, whose presence is a requirement
// for the type propagation phase. Note that this is to satisfy statement (a)
// of the SsaBuilder (see ssa_builder.h).
SsaRedundantPhiElimination(graph_).Run();
// 3) Fix the type for null constants which are part of an equality comparison.
// We need to do this after redundant phi elimination, to ensure the only cases
// that we can see are reference comparison against 0. The redundant phi
// elimination ensures we do not see a phi taking two 0 constants in a HEqual
// or HNotEqual.
FixNullConstantType();
// 4) Compute type of reference type instructions. The pass assumes that
// NullConstant has been fixed up.
ReferenceTypePropagation(graph_, dex_cache_, handles_, /* is_first_run */ true).Run();
// 5) HInstructionBuilder duplicated ArrayGet instructions with ambiguous type
// (int/float or long/double) and marked ArraySets with ambiguous input type.
// Now that RTP computed the type of the array input, the ambiguity can be
// resolved and the correct equivalents kept.
if (!FixAmbiguousArrayOps()) {
return kAnalysisFailAmbiguousArrayOp;
}
// 6) Mark dead phis. This will mark phis which are not used by instructions
// or other live phis. If compiling as debuggable code, phis will also be kept
// live if they have an environment use.
SsaDeadPhiElimination dead_phi_elimimation(graph_);
dead_phi_elimimation.MarkDeadPhis();
// 7) Make sure environments use the right phi equivalent: a phi marked dead
// can have a phi equivalent that is not dead. In that case we have to replace
// it with the live equivalent because deoptimization and try/catch rely on
// environments containing values of all live vregs at that point. Note that
// there can be multiple phis for the same Dex register that are live
// (for example when merging constants), in which case it is okay for the
// environments to just reference one.
FixEnvironmentPhis();
// 8) Now that the right phis are used for the environments, we can eliminate
// phis we do not need. Regardless of the debuggable status, this phase is
/// necessary for statement (b) of the SsaBuilder (see ssa_builder.h), as well
// as for the code generation, which does not deal with phis of conflicting
// input types.
dead_phi_elimimation.EliminateDeadPhis();
// 9) HInstructionBuidler replaced uses of NewInstances of String with the
// results of their corresponding StringFactory calls. Unless the String
// objects are used before they are initialized, they can be replaced with
// NullConstant. Note that this optimization is valid only if unsimplified
// code does not use the uninitialized value because we assume execution can
// be deoptimized at any safepoint. We must therefore perform it before any
// other optimizations.
RemoveRedundantUninitializedStrings();
graph_->SetInSsaForm();
return kAnalysisSuccess;
}
/**
* Constants in the Dex format are not typed. So the builder types them as
* integers, but when doing the SSA form, we might realize the constant
* is used for floating point operations. We create a floating-point equivalent
* constant to make the operations correctly typed.
*/
HFloatConstant* SsaBuilder::GetFloatEquivalent(HIntConstant* constant) {
// We place the floating point constant next to this constant.
HFloatConstant* result = constant->GetNext()->AsFloatConstant();
if (result == nullptr) {
float value = bit_cast<float, int32_t>(constant->GetValue());
result = new (graph_->GetArena()) HFloatConstant(value);
constant->GetBlock()->InsertInstructionBefore(result, constant->GetNext());
graph_->CacheFloatConstant(result);
} else {
// If there is already a constant with the expected type, we know it is
// the floating point equivalent of this constant.
DCHECK_EQ((bit_cast<int32_t, float>(result->GetValue())), constant->GetValue());
}
return result;
}
/**
* Wide constants in the Dex format are not typed. So the builder types them as
* longs, but when doing the SSA form, we might realize the constant
* is used for floating point operations. We create a floating-point equivalent
* constant to make the operations correctly typed.
*/
HDoubleConstant* SsaBuilder::GetDoubleEquivalent(HLongConstant* constant) {
// We place the floating point constant next to this constant.
HDoubleConstant* result = constant->GetNext()->AsDoubleConstant();
if (result == nullptr) {
double value = bit_cast<double, int64_t>(constant->GetValue());
result = new (graph_->GetArena()) HDoubleConstant(value);
constant->GetBlock()->InsertInstructionBefore(result, constant->GetNext());
graph_->CacheDoubleConstant(result);
} else {
// If there is already a constant with the expected type, we know it is
// the floating point equivalent of this constant.
DCHECK_EQ((bit_cast<int64_t, double>(result->GetValue())), constant->GetValue());
}
return result;
}
/**
* Because of Dex format, we might end up having the same phi being
* used for non floating point operations and floating point / reference operations.
* Because we want the graph to be correctly typed (and thereafter avoid moves between
* floating point registers and core registers), we need to create a copy of the
* phi with a floating point / reference type.
*/
HPhi* SsaBuilder::GetFloatDoubleOrReferenceEquivalentOfPhi(HPhi* phi, Primitive::Type type) {
DCHECK(phi->IsLive()) << "Cannot get equivalent of a dead phi since it would create a live one.";
// We place the floating point /reference phi next to this phi.
HInstruction* next = phi->GetNext();
if (next != nullptr
&& next->AsPhi()->GetRegNumber() == phi->GetRegNumber()
&& next->GetType() != type) {
// Move to the next phi to see if it is the one we are looking for.
next = next->GetNext();
}
if (next == nullptr
|| (next->AsPhi()->GetRegNumber() != phi->GetRegNumber())
|| (next->GetType() != type)) {
ArenaAllocator* allocator = graph_->GetArena();
HPhi* new_phi = new (allocator) HPhi(allocator, phi->GetRegNumber(), phi->InputCount(), type);
for (size_t i = 0, e = phi->InputCount(); i < e; ++i) {
// Copy the inputs. Note that the graph may not be correctly typed
// by doing this copy, but the type propagation phase will fix it.
new_phi->SetRawInputAt(i, phi->InputAt(i));
}
phi->GetBlock()->InsertPhiAfter(new_phi, phi);
DCHECK(new_phi->IsLive());
return new_phi;
} else {
// An existing equivalent was found. If it is dead, conflict was previously
// identified and we return nullptr instead.
HPhi* next_phi = next->AsPhi();
DCHECK_EQ(next_phi->GetType(), type);
return next_phi->IsLive() ? next_phi : nullptr;
}
}
HArrayGet* SsaBuilder::GetFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) {
DCHECK(Primitive::IsIntegralType(aget->GetType()));
if (!Primitive::IsIntOrLongType(aget->GetType())) {
// Cannot type boolean, char, byte, short to float/double.
return nullptr;
}
DCHECK(ContainsElement(ambiguous_agets_, aget));
if (agets_fixed_) {
// This used to be an ambiguous ArrayGet but its type has been resolved to
// int/long. Requesting a float/double equivalent should lead to a conflict.
if (kIsDebugBuild) {
ScopedObjectAccess soa(Thread::Current());
DCHECK(Primitive::IsIntOrLongType(GetPrimitiveArrayComponentType(aget->GetArray())));
}
return nullptr;
} else {
// This is an ambiguous ArrayGet which has not been resolved yet. Return an
// equivalent float/double instruction to use until it is resolved.
HArrayGet* equivalent = FindFloatOrDoubleEquivalentOfArrayGet(aget);
return (equivalent == nullptr) ? CreateFloatOrDoubleEquivalentOfArrayGet(aget) : equivalent;
}
}
HInstruction* SsaBuilder::GetFloatOrDoubleEquivalent(HInstruction* value, Primitive::Type type) {
if (value->IsArrayGet()) {
return GetFloatOrDoubleEquivalentOfArrayGet(value->AsArrayGet());
} else if (value->IsLongConstant()) {
return GetDoubleEquivalent(value->AsLongConstant());
} else if (value->IsIntConstant()) {
return GetFloatEquivalent(value->AsIntConstant());
} else if (value->IsPhi()) {
return GetFloatDoubleOrReferenceEquivalentOfPhi(value->AsPhi(), type);
} else {
return nullptr;
}
}
HInstruction* SsaBuilder::GetReferenceTypeEquivalent(HInstruction* value) {
if (value->IsIntConstant() && value->AsIntConstant()->GetValue() == 0) {
return graph_->GetNullConstant();
} else if (value->IsPhi()) {
return GetFloatDoubleOrReferenceEquivalentOfPhi(value->AsPhi(), Primitive::kPrimNot);
} else {
return nullptr;
}
}
} // namespace art