Revert "Revert "Refactor HGraphBuilder and SsaBuilder to remove HLocals""

This patch merges the instruction-building phases from HGraphBuilder
and SsaBuilder into a single HInstructionBuilder class. As a result,
it is not necessary to generate HLocal, HLoadLocal and HStoreLocal
instructions any more, as the builder produces SSA form directly.

Saves 5-15% of arena-allocated memory (see bug for more data):
  GMS      20.46MB  =>  19.26MB  (-5.86%)
  Maps     24.12MB  =>  21.47MB  (-10.98%)
  YouTube  28.60MB  =>  26.01MB  (-9.05%)

This CL fixed an issue with parsing quickened instructions.

Bug: 27894376
Bug: 27998571
Bug: 27995065

Change-Id: I20dbe1bf2d0fe296377478db98cb86cba695e694

1 files changed, 50 insertions, 381 deletions

diff --git a/compiler/optimizing/ssa_builder.cc b/compiler/optimizing/ssa_builder.cc
index 5a05256628..eeadbeb0d1 100644
--- a/compiler/optimizing/ssa_builder.cc
+++ b/compiler/optimizing/ssa_builder.cc
@@ -23,30 +23,9 @@
 
 namespace art {
 
-void SsaBuilder::SetLoopHeaderPhiInputs() {
-  for (size_t i = loop_headers_.size(); i > 0; --i) {
-    HBasicBlock* block = loop_headers_[i - 1];
-    for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
-      HPhi* phi = it.Current()->AsPhi();
-      size_t vreg = phi->GetRegNumber();
-      for (HBasicBlock* predecessor : block->GetPredecessors()) {
-        HInstruction* value = ValueOfLocal(predecessor, vreg);
-        if (value == nullptr) {
-          // Vreg is undefined at this predecessor. Mark it dead and leave with
-          // fewer inputs than predecessors. SsaChecker will fail if not removed.
-          phi->SetDead();
-          break;
-        } else {
-          phi->AddInput(value);
-        }
-      }
-    }
-  }
-}
-
 void SsaBuilder::FixNullConstantType() {
   // The order doesn't matter here.
-  for (HReversePostOrderIterator itb(*GetGraph()); !itb.Done(); itb.Advance()) {
+  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()) {
@@ -71,14 +50,14 @@ void SsaBuilder::FixNullConstantType() {
       // can only be the 0 constant.
       DCHECK(int_operand->IsIntConstant()) << int_operand->DebugName();
       DCHECK_EQ(0, int_operand->AsIntConstant()->GetValue());
-      equality_instr->ReplaceInput(GetGraph()->GetNullConstant(), int_operand == right ? 1 : 0);
+      equality_instr->ReplaceInput(graph_->GetNullConstant(), int_operand == right ? 1 : 0);
     }
   }
 }
 
 void SsaBuilder::EquivalentPhisCleanup() {
   // The order doesn't matter here.
-  for (HReversePostOrderIterator itb(*GetGraph()); !itb.Done(); itb.Advance()) {
+  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();
@@ -100,7 +79,7 @@ void SsaBuilder::EquivalentPhisCleanup() {
 }
 
 void SsaBuilder::FixEnvironmentPhis() {
-  for (HReversePostOrderIterator it(*GetGraph()); !it.Done(); it.Advance()) {
+  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();
@@ -254,9 +233,9 @@ bool SsaBuilder::UpdatePrimitiveType(HPhi* phi, ArenaVector<HPhi*>* worklist) {
 }
 
 void SsaBuilder::RunPrimitiveTypePropagation() {
-  ArenaVector<HPhi*> worklist(GetGraph()->GetArena()->Adapter());
+  ArenaVector<HPhi*> worklist(graph_->GetArena()->Adapter());
 
-  for (HReversePostOrderIterator it(*GetGraph()); !it.Done(); it.Advance()) {
+  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()) {
@@ -300,8 +279,14 @@ void SsaBuilder::ProcessPrimitiveTypePropagationWorklist(ArenaVector<HPhi*>* wor
 static HArrayGet* FindFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) {
   Primitive::Type type = aget->GetType();
   DCHECK(Primitive::IsIntOrLongType(type));
-  HArrayGet* next = aget->GetNext()->AsArrayGet();
-  return (next != nullptr && next->IsEquivalentOf(aget)) ? next : nullptr;
+  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) {
@@ -334,7 +319,7 @@ bool SsaBuilder::FixAmbiguousArrayOps() {
   // 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(GetGraph()->GetArena()->Adapter());
+  ArenaVector<HPhi*> worklist(graph_->GetArena()->Adapter());
 
   {
     ScopedObjectAccess soa(Thread::Current());
@@ -452,7 +437,7 @@ static bool HasAliasInEnvironments(HInstruction* instruction) {
 }
 
 void SsaBuilder::RemoveRedundantUninitializedStrings() {
-  if (GetGraph()->IsDebuggable()) {
+  if (graph_->IsDebuggable()) {
     // Do not perform the optimization for consistency with the interpreter
     // which always allocates an object for new-instance of String.
     return;
@@ -460,11 +445,13 @@ void SsaBuilder::RemoveRedundantUninitializedStrings() {
 
   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(GetGraph()->GetNullConstant());
+      new_instance->ReplaceWith(graph_->GetNullConstant());
       new_instance->GetBlock()->RemoveInstruction(new_instance);
 
       // Remove LoadClass if not needed any more.
@@ -495,57 +482,47 @@ void SsaBuilder::RemoveRedundantUninitializedStrings() {
 }
 
 GraphAnalysisResult SsaBuilder::BuildSsa() {
-  DCHECK(!GetGraph()->IsInSsaForm());
+  DCHECK(!graph_->IsInSsaForm());
 
-  // 1) Visit in reverse post order. We need to have all predecessors of a block
-  // visited (with the exception of loops) in order to create the right environment
-  // for that block. For loops, we create phis whose inputs will be set in 2).
-  for (HReversePostOrderIterator it(*GetGraph()); !it.Done(); it.Advance()) {
-    VisitBasicBlock(it.Current());
-  }
-
-  // 2) Set inputs of loop header phis.
-  SetLoopHeaderPhiInputs();
-
-  // 3) Propagate types of phis. At this point, phis are typed void in the general
+  // 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();
 
-  // 4) Now that the correct primitive types have been assigned, we can get rid
+  // 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(GetGraph()).Run();
+  SsaRedundantPhiElimination(graph_).Run();
 
-  // 5) Fix the type for null constants which are part of an equality comparison.
+  // 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();
 
-  // 6) Compute type of reference type instructions. The pass assumes that
+  // 4) Compute type of reference type instructions. The pass assumes that
   // NullConstant has been fixed up.
-  ReferenceTypePropagation(GetGraph(), handles_, /* is_first_run */ true).Run();
+  ReferenceTypePropagation(graph_, handles_, /* is_first_run */ true).Run();
 
-  // 7) Step 1) 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.
+  // 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;
   }
 
-  // 8) Mark dead phis. This will mark phis which are not used by instructions
+  // 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(GetGraph());
+  SsaDeadPhiElimination dead_phi_elimimation(graph_);
   dead_phi_elimimation.MarkDeadPhis();
 
-  // 9) Make sure environments use the right phi equivalent: a phi marked dead
+  // 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
@@ -554,165 +531,26 @@ GraphAnalysisResult SsaBuilder::BuildSsa() {
   // environments to just reference one.
   FixEnvironmentPhis();
 
-  // 10) Now that the right phis are used for the environments, we can eliminate
+  // 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();
 
-  // 11) Step 1) 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.
+  // 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();
 
-  // 12) Clear locals.
-  for (HInstructionIterator it(GetGraph()->GetEntryBlock()->GetInstructions());
-       !it.Done();
-       it.Advance()) {
-    HInstruction* current = it.Current();
-    if (current->IsLocal()) {
-      current->GetBlock()->RemoveInstruction(current);
-    }
-  }
-
-  GetGraph()->SetInSsaForm();
+  graph_->SetInSsaForm();
   return kAnalysisSuccess;
 }
 
-ArenaVector<HInstruction*>* SsaBuilder::GetLocalsFor(HBasicBlock* block) {
-  ArenaVector<HInstruction*>* locals = &locals_for_[block->GetBlockId()];
-  const size_t vregs = GetGraph()->GetNumberOfVRegs();
-  if (locals->empty() && vregs != 0u) {
-    locals->resize(vregs, nullptr);
-
-    if (block->IsCatchBlock()) {
-      ArenaAllocator* arena = GetGraph()->GetArena();
-      // We record incoming inputs of catch phis at throwing instructions and
-      // must therefore eagerly create the phis. Phis for undefined vregs will
-      // be deleted when the first throwing instruction with the vreg undefined
-      // is encountered. Unused phis will be removed by dead phi analysis.
-      for (size_t i = 0; i < vregs; ++i) {
-        // No point in creating the catch phi if it is already undefined at
-        // the first throwing instruction.
-        HInstruction* current_local_value = (*current_locals_)[i];
-        if (current_local_value != nullptr) {
-          HPhi* phi = new (arena) HPhi(
-              arena,
-              i,
-              0,
-              current_local_value->GetType());
-          block->AddPhi(phi);
-          (*locals)[i] = phi;
-        }
-      }
-    }
-  }
-  return locals;
-}
-
-HInstruction* SsaBuilder::ValueOfLocal(HBasicBlock* block, size_t local) {
-  ArenaVector<HInstruction*>* locals = GetLocalsFor(block);
-  return (*locals)[local];
-}
-
-void SsaBuilder::VisitBasicBlock(HBasicBlock* block) {
-  current_locals_ = GetLocalsFor(block);
-
-  if (block->IsCatchBlock()) {
-    // Catch phis were already created and inputs collected from throwing sites.
-    if (kIsDebugBuild) {
-      // Make sure there was at least one throwing instruction which initialized
-      // locals (guaranteed by HGraphBuilder) and that all try blocks have been
-      // visited already (from HTryBoundary scoping and reverse post order).
-      bool catch_block_visited = false;
-      for (HReversePostOrderIterator it(*GetGraph()); !it.Done(); it.Advance()) {
-        HBasicBlock* current = it.Current();
-        if (current == block) {
-          catch_block_visited = true;
-        } else if (current->IsTryBlock() &&
-                   current->GetTryCatchInformation()->GetTryEntry().HasExceptionHandler(*block)) {
-          DCHECK(!catch_block_visited) << "Catch block visited before its try block.";
-        }
-      }
-      DCHECK_EQ(current_locals_->size(), GetGraph()->GetNumberOfVRegs())
-          << "No instructions throwing into a live catch block.";
-    }
-  } else if (block->IsLoopHeader()) {
-    // If the block is a loop header, we know we only have visited the pre header
-    // because we are visiting in reverse post order. We create phis for all initialized
-    // locals from the pre header. Their inputs will be populated at the end of
-    // the analysis.
-    for (size_t local = 0; local < current_locals_->size(); ++local) {
-      HInstruction* incoming = ValueOfLocal(block->GetLoopInformation()->GetPreHeader(), local);
-      if (incoming != nullptr) {
-        HPhi* phi = new (GetGraph()->GetArena()) HPhi(
-            GetGraph()->GetArena(),
-            local,
-            0,
-            incoming->GetType());
-        block->AddPhi(phi);
-        (*current_locals_)[local] = phi;
-      }
-    }
-    // Save the loop header so that the last phase of the analysis knows which
-    // blocks need to be updated.
-    loop_headers_.push_back(block);
-  } else if (block->GetPredecessors().size() > 0) {
-    // All predecessors have already been visited because we are visiting in reverse post order.
-    // We merge the values of all locals, creating phis if those values differ.
-    for (size_t local = 0; local < current_locals_->size(); ++local) {
-      bool one_predecessor_has_no_value = false;
-      bool is_different = false;
-      HInstruction* value = ValueOfLocal(block->GetPredecessors()[0], local);
-
-      for (HBasicBlock* predecessor : block->GetPredecessors()) {
-        HInstruction* current = ValueOfLocal(predecessor, local);
-        if (current == nullptr) {
-          one_predecessor_has_no_value = true;
-          break;
-        } else if (current != value) {
-          is_different = true;
-        }
-      }
-
-      if (one_predecessor_has_no_value) {
-        // If one predecessor has no value for this local, we trust the verifier has
-        // successfully checked that there is a store dominating any read after this block.
-        continue;
-      }
-
-      if (is_different) {
-        HInstruction* first_input = ValueOfLocal(block->GetPredecessors()[0], local);
-        HPhi* phi = new (GetGraph()->GetArena()) HPhi(
-            GetGraph()->GetArena(),
-            local,
-            block->GetPredecessors().size(),
-            first_input->GetType());
-        for (size_t i = 0; i < block->GetPredecessors().size(); i++) {
-          HInstruction* pred_value = ValueOfLocal(block->GetPredecessors()[i], local);
-          phi->SetRawInputAt(i, pred_value);
-        }
-        block->AddPhi(phi);
-        value = phi;
-      }
-      (*current_locals_)[local] = value;
-    }
-  }
-
-  // Visit all instructions. The instructions of interest are:
-  // - HLoadLocal: replace them with the current value of the local.
-  // - HStoreLocal: update current value of the local and remove the instruction.
-  // - Instructions that require an environment: populate their environment
-  //   with the current values of the locals.
-  for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
-    it.Current()->Accept(this);
-  }
-}
-
 /**
  * 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
@@ -723,11 +561,10 @@ HFloatConstant* SsaBuilder::GetFloatEquivalent(HIntConstant* constant) {
   // We place the floating point constant next to this constant.
   HFloatConstant* result = constant->GetNext()->AsFloatConstant();
   if (result == nullptr) {
-    HGraph* graph = constant->GetBlock()->GetGraph();
-    ArenaAllocator* allocator = graph->GetArena();
-    result = new (allocator) HFloatConstant(bit_cast<float, int32_t>(constant->GetValue()));
+    float value = bit_cast<float, int32_t>(constant->GetValue());
+    result = new (graph_->GetArena()) HFloatConstant(value);
     constant->GetBlock()->InsertInstructionBefore(result, constant->GetNext());
-    graph->CacheFloatConstant(result);
+    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.
@@ -746,11 +583,10 @@ HDoubleConstant* SsaBuilder::GetDoubleEquivalent(HLongConstant* constant) {
   // We place the floating point constant next to this constant.
   HDoubleConstant* result = constant->GetNext()->AsDoubleConstant();
   if (result == nullptr) {
-    HGraph* graph = constant->GetBlock()->GetGraph();
-    ArenaAllocator* allocator = graph->GetArena();
-    result = new (allocator) HDoubleConstant(bit_cast<double, int64_t>(constant->GetValue()));
+    double value = bit_cast<double, int64_t>(constant->GetValue());
+    result = new (graph_->GetArena()) HDoubleConstant(value);
     constant->GetBlock()->InsertInstructionBefore(result, constant->GetNext());
-    graph->CacheDoubleConstant(result);
+    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.
@@ -781,7 +617,7 @@ HPhi* SsaBuilder::GetFloatDoubleOrReferenceEquivalentOfPhi(HPhi* phi, Primitive:
   if (next == nullptr
       || (next->AsPhi()->GetRegNumber() != phi->GetRegNumber())
       || (next->GetType() != type)) {
-    ArenaAllocator* allocator = phi->GetBlock()->GetGraph()->GetArena();
+    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
@@ -841,7 +677,7 @@ HInstruction* SsaBuilder::GetFloatOrDoubleEquivalent(HInstruction* value, Primit
 
 HInstruction* SsaBuilder::GetReferenceTypeEquivalent(HInstruction* value) {
   if (value->IsIntConstant() && value->AsIntConstant()->GetValue() == 0) {
-    return value->GetBlock()->GetGraph()->GetNullConstant();
+    return graph_->GetNullConstant();
   } else if (value->IsPhi()) {
     return GetFloatDoubleOrReferenceEquivalentOfPhi(value->AsPhi(), Primitive::kPrimNot);
   } else {
@@ -849,171 +685,4 @@ HInstruction* SsaBuilder::GetReferenceTypeEquivalent(HInstruction* value) {
   }
 }
 
-void SsaBuilder::VisitLoadLocal(HLoadLocal* load) {
-  Primitive::Type load_type = load->GetType();
-  HInstruction* value = (*current_locals_)[load->GetLocal()->GetRegNumber()];
-  // If the operation requests a specific type, we make sure its input is of that type.
-  if (load_type != value->GetType()) {
-    if (load_type == Primitive::kPrimFloat || load_type == Primitive::kPrimDouble) {
-      value = GetFloatOrDoubleEquivalent(value, load_type);
-    } else if (load_type == Primitive::kPrimNot) {
-      value = GetReferenceTypeEquivalent(value);
-    }
-  }
-
-  load->ReplaceWith(value);
-  load->GetBlock()->RemoveInstruction(load);
-}
-
-void SsaBuilder::VisitStoreLocal(HStoreLocal* store) {
-  uint32_t reg_number = store->GetLocal()->GetRegNumber();
-  HInstruction* stored_value = store->InputAt(1);
-  Primitive::Type stored_type = stored_value->GetType();
-  DCHECK_NE(stored_type, Primitive::kPrimVoid);
-
-  // Storing into vreg `reg_number` may implicitly invalidate the surrounding
-  // registers. Consider the following cases:
-  // (1) Storing a wide value must overwrite previous values in both `reg_number`
-  //     and `reg_number+1`. We store `nullptr` in `reg_number+1`.
-  // (2) If vreg `reg_number-1` holds a wide value, writing into `reg_number`
-  //     must invalidate it. We store `nullptr` in `reg_number-1`.
-  // Consequently, storing a wide value into the high vreg of another wide value
-  // will invalidate both `reg_number-1` and `reg_number+1`.
-
-  if (reg_number != 0) {
-    HInstruction* local_low = (*current_locals_)[reg_number - 1];
-    if (local_low != nullptr && Primitive::Is64BitType(local_low->GetType())) {
-      // The vreg we are storing into was previously the high vreg of a pair.
-      // We need to invalidate its low vreg.
-      DCHECK((*current_locals_)[reg_number] == nullptr);
-      (*current_locals_)[reg_number - 1] = nullptr;
-    }
-  }
-
-  (*current_locals_)[reg_number] = stored_value;
-  if (Primitive::Is64BitType(stored_type)) {
-    // We are storing a pair. Invalidate the instruction in the high vreg.
-    (*current_locals_)[reg_number + 1] = nullptr;
-  }
-
-  store->GetBlock()->RemoveInstruction(store);
-}
-
-bool SsaBuilder::IsFirstAtThrowingDexPc(HInstruction* instruction) const {
-  uint32_t dex_pc = instruction->GetDexPc();
-  if (dex_pc == kNoDexPc) {
-    return false;
-  }
-
-  // Needs to be the first HInstruction with this dex_pc.
-  HInstruction* previous = instruction->GetPrevious();
-  if (previous != nullptr && previous->GetDexPc() == dex_pc) {
-    return false;
-  }
-
-  if (instruction->IsControlFlow() && !instruction->IsThrow()) {
-    // Special-case non-throwing control-flow HInstruction because artifically
-    // created ones are given dex_pc of the nearest bytecode instructions.
-    return false;
-  }
-
-  return IsThrowingDexInstruction(GetDexInstructionAt(code_item_, dex_pc));
-}
-
-void SsaBuilder::VisitInstruction(HInstruction* instruction) {
-  if (instruction->NeedsEnvironment()) {
-    HEnvironment* environment = new (GetGraph()->GetArena()) HEnvironment(
-        GetGraph()->GetArena(),
-        current_locals_->size(),
-        GetGraph()->GetDexFile(),
-        GetGraph()->GetMethodIdx(),
-        instruction->GetDexPc(),
-        GetGraph()->GetInvokeType(),
-        instruction);
-    environment->CopyFrom(*current_locals_);
-    instruction->SetRawEnvironment(environment);
-  }
-
-  // If in a try block, propagate values of locals into catch blocks.
-  if (instruction->GetBlock()->IsTryBlock() && IsFirstAtThrowingDexPc(instruction)) {
-    const HTryBoundary& try_entry =
-        instruction->GetBlock()->GetTryCatchInformation()->GetTryEntry();
-    for (HBasicBlock* catch_block : try_entry.GetExceptionHandlers()) {
-      ArenaVector<HInstruction*>* handler_locals = GetLocalsFor(catch_block);
-      DCHECK_EQ(handler_locals->size(), current_locals_->size());
-      for (size_t vreg = 0, e = current_locals_->size(); vreg < e; ++vreg) {
-        HInstruction* handler_value = (*handler_locals)[vreg];
-        if (handler_value == nullptr) {
-          // Vreg was undefined at a previously encountered throwing instruction
-          // and the catch phi was deleted. Do not record the local value.
-          continue;
-        }
-        DCHECK(handler_value->IsPhi());
-
-        HInstruction* local_value = (*current_locals_)[vreg];
-        if (local_value == nullptr) {
-          // This is the first instruction throwing into `catch_block` where
-          // `vreg` is undefined. Delete the catch phi.
-          catch_block->RemovePhi(handler_value->AsPhi());
-          (*handler_locals)[vreg] = nullptr;
-        } else {
-          // Vreg has been defined at all instructions throwing into `catch_block`
-          // encountered so far. Record the local value in the catch phi.
-          handler_value->AsPhi()->AddInput(local_value);
-        }
-      }
-    }
-  }
-}
-
-void SsaBuilder::VisitArrayGet(HArrayGet* aget) {
-  Primitive::Type type = aget->GetType();
-  DCHECK(!Primitive::IsFloatingPointType(type));
-  if (Primitive::IsIntOrLongType(type)) {
-    ambiguous_agets_.push_back(aget);
-  }
-  VisitInstruction(aget);
-}
-
-void SsaBuilder::VisitArraySet(HArraySet* aset) {
-  Primitive::Type type = aset->GetValue()->GetType();
-  if (Primitive::IsIntOrLongType(type)) {
-    ambiguous_asets_.push_back(aset);
-  }
-  VisitInstruction(aset);
-}
-
-void SsaBuilder::VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) {
-  VisitInstruction(invoke);
-
-  if (invoke->IsStringInit()) {
-    // This is a StringFactory call which acts as a String constructor. Its
-    // result replaces the empty String pre-allocated by NewInstance.
-    HInstruction* arg_this = invoke->GetAndRemoveThisArgumentOfStringInit();
-
-    // Replacing the NewInstance might render it redundant. Keep a list of these
-    // to be visited once it is clear whether it is has remaining uses.
-    if (arg_this->IsNewInstance()) {
-      HNewInstance* new_instance = arg_this->AsNewInstance();
-      // Note that in some rare cases (b/27847265), the same NewInstance may be seen
-      // multiple times. We should only consider it once for removal, so we
-      // ensure it is not added more than once.
-      if (!ContainsElement(uninitialized_strings_, new_instance)) {
-        uninitialized_strings_.push_back(new_instance);
-      }
-    } else {
-      DCHECK(arg_this->IsPhi());
-      // NewInstance is not the direct input of the StringFactory call. It might
-      // be redundant but optimizing this case is not worth the effort.
-    }
-
-    // Walk over all vregs and replace any occurrence of `arg_this` with `invoke`.
-    for (size_t vreg = 0, e = current_locals_->size(); vreg < e; ++vreg) {
-      if ((*current_locals_)[vreg] == arg_this) {
-        (*current_locals_)[vreg] = invoke;
-      }
-    }
-  }
-}
-
 }  // namespace art