Defer creating Handles for HConstants to the code generation phase.

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/10544196

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12048 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/lithium-codegen-arm.cc

@@ -322,7 +322,8 @@ Register LCodeGen::EmitLoadRegister(LOperand* op, Register scratch) {
     return ToRegister(op->index());
   } else if (op->IsConstantOperand()) {
     LConstantOperand* const_op = LConstantOperand::cast(op);
-    Handle<Object> literal = chunk_->LookupLiteral(const_op);
+    HConstant* constant = chunk_->LookupConstant(const_op);
+    Handle<Object> literal = constant->handle();
     Representation r = chunk_->LookupLiteralRepresentation(const_op);
     if (r.IsInteger32()) {
       ASSERT(literal->IsNumber());
@@ -360,7 +361,8 @@ DoubleRegister LCodeGen::EmitLoadDoubleRegister(LOperand* op,
     return ToDoubleRegister(op->index());
   } else if (op->IsConstantOperand()) {
     LConstantOperand* const_op = LConstantOperand::cast(op);
-    Handle<Object> literal = chunk_->LookupLiteral(const_op);
+    HConstant* constant = chunk_->LookupConstant(const_op);
+    Handle<Object> literal = constant->handle();
     Representation r = chunk_->LookupLiteralRepresentation(const_op);
     if (r.IsInteger32()) {
       ASSERT(literal->IsNumber());
@@ -386,9 +388,9 @@ DoubleRegister LCodeGen::EmitLoadDoubleRegister(LOperand* op,
 
 
 Handle<Object> LCodeGen::ToHandle(LConstantOperand* op) const {
-  Handle<Object> literal = chunk_->LookupLiteral(op);
+  HConstant* constant = chunk_->LookupConstant(op);
   ASSERT(chunk_->LookupLiteralRepresentation(op).IsTagged());
-  return literal;
+  return constant->handle();
 }
 
 
@@ -398,33 +400,33 @@ bool LCodeGen::IsInteger32(LConstantOperand* op) const {
 
 
 int LCodeGen::ToInteger32(LConstantOperand* op) const {
-  Handle<Object> value = chunk_->LookupLiteral(op);
+  HConstant* constant = chunk_->LookupConstant(op);
   ASSERT(chunk_->LookupLiteralRepresentation(op).IsInteger32());
-  ASSERT(static_cast<double>(static_cast<int32_t>(value->Number())) ==
-      value->Number());
-  return static_cast<int32_t>(value->Number());
+  ASSERT(constant->HasInteger32Value());
+  return constant->Integer32Value();
 }
 
 
 double LCodeGen::ToDouble(LConstantOperand* op) const {
-  Handle<Object> value = chunk_->LookupLiteral(op);
-  return value->Number();
+  HConstant* constant = chunk_->LookupConstant(op);
+  ASSERT(constant->HasDoubleValue());
+  return constant->DoubleValue();
 }
 
 
 Operand LCodeGen::ToOperand(LOperand* op) {
   if (op->IsConstantOperand()) {
     LConstantOperand* const_op = LConstantOperand::cast(op);
-    Handle<Object> literal = chunk_->LookupLiteral(const_op);
+    HConstant* constant = chunk()->LookupConstant(const_op);
     Representation r = chunk_->LookupLiteralRepresentation(const_op);
     if (r.IsInteger32()) {
-      ASSERT(literal->IsNumber());
-      return Operand(static_cast<int32_t>(literal->Number()));
+      ASSERT(constant->HasInteger32Value());
+      return Operand(constant->Integer32Value());
     } else if (r.IsDouble()) {
       Abort("ToOperand Unsupported double immediate.");
     }
     ASSERT(r.IsTagged());
-    return Operand(literal);
+    return Operand(constant->handle());
   } else if (op->IsRegister()) {
     return Operand(ToRegister(op));
   } else if (op->IsDoubleRegister()) {
@@ -553,8 +555,8 @@ void LCodeGen::AddToTranslation(Translation* translation,
     DoubleRegister reg = ToDoubleRegister(op);
     translation->StoreDoubleRegister(reg);
   } else if (op->IsConstantOperand()) {
-    Handle<Object> literal = chunk()->LookupLiteral(LConstantOperand::cast(op));
-    int src_index = DefineDeoptimizationLiteral(literal);
+    HConstant* constant = chunk()->LookupConstant(LConstantOperand::cast(op));
+    int src_index = DefineDeoptimizationLiteral(constant->handle());
     translation->StoreLiteral(src_index);
   } else {
     UNREACHABLE();

src/hydrogen-instructions.cc

@@ -1385,41 +1385,78 @@ void HEnterInlined::PrintDataTo(StringStream* stream) {
 }
 
 
+static bool IsInteger32(double value) {
+  double roundtrip_value = static_cast<double>(static_cast<int32_t>(value));
+  return BitCast<int64_t>(roundtrip_value) == BitCast<int64_t>(value);
+}
+
+
 HConstant::HConstant(Handle<Object> handle, Representation r)
     : handle_(handle),
       has_int32_value_(false),
-      has_double_value_(false),
-      int32_value_(0),
-      double_value_(0)  {
+      has_double_value_(false) {
   set_representation(r);
   SetFlag(kUseGVN);
   if (handle_->IsNumber()) {
     double n = handle_->Number();
-    double roundtrip_value = static_cast<double>(static_cast<int32_t>(n));
-    has_int32_value_ = BitCast<int64_t>(roundtrip_value) == BitCast<int64_t>(n);
-    if (has_int32_value_) int32_value_ = static_cast<int32_t>(n);
+    has_int32_value_ = IsInteger32(n);
+    int32_value_ = DoubleToInt32(n);
     double_value_ = n;
     has_double_value_ = true;
   }
 }
 
 
+HConstant::HConstant(int32_t integer_value, Representation r)
+    : has_int32_value_(true),
+      has_double_value_(true),
+      int32_value_(integer_value),
+      double_value_(FastI2D(integer_value)) {
+  set_representation(r);
+  SetFlag(kUseGVN);
+}
+
+
+HConstant::HConstant(double double_value, Representation r)
+    : has_int32_value_(IsInteger32(double_value)),
+      has_double_value_(true),
+      int32_value_(DoubleToInt32(double_value)),
+      double_value_(double_value) {
+  set_representation(r);
+  SetFlag(kUseGVN);
+}
+
+
 HConstant* HConstant::CopyToRepresentation(Representation r, Zone* zone) const {
   if (r.IsInteger32() && !has_int32_value_) return NULL;
   if (r.IsDouble() && !has_double_value_) return NULL;
+  if (handle_.is_null()) {
+    ASSERT(has_int32_value_ || has_double_value_);
+    if (has_int32_value_) return new(zone) HConstant(int32_value_, r);
+    return new(zone) HConstant(double_value_, r);
+  }
   return new(zone) HConstant(handle_, r);
 }
 
 
 HConstant* HConstant::CopyToTruncatedInt32(Zone* zone) const {
-  if (!has_double_value_) return NULL;
-  int32_t truncated = NumberToInt32(*handle_);
-  return new(zone) HConstant(FACTORY->NewNumberFromInt(truncated),
-                             Representation::Integer32());
+  if (has_int32_value_) {
+    if (handle_.is_null()) {
+      return new(zone) HConstant(int32_value_, Representation::Integer32());
+    } else {
+      // Re-use the existing Handle if possible.
+      return new(zone) HConstant(handle_, Representation::Integer32());
+    }
+  } else if (has_double_value_) {
+    return new(zone) HConstant(DoubleToInt32(double_value_),
+                               Representation::Integer32());
+  } else {
+    return NULL;
+  }
 }
 
 
-bool HConstant::ToBoolean() const {
+bool HConstant::ToBoolean() {
   // Converts the constant's boolean value according to
   // ECMAScript section 9.2 ToBoolean conversion.
   if (HasInteger32Value()) return Integer32Value() != 0;
@@ -1427,17 +1464,25 @@ bool HConstant::ToBoolean() const {
     double v = DoubleValue();
     return v != 0 && !isnan(v);
   }
-  if (handle()->IsTrue()) return true;
-  if (handle()->IsFalse()) return false;
-  if (handle()->IsUndefined()) return false;
-  if (handle()->IsNull()) return false;
-  if (handle()->IsString() &&
-      String::cast(*handle())->length() == 0) return false;
+  Handle<Object> literal = handle();
+  if (literal->IsTrue()) return true;
+  if (literal->IsFalse()) return false;
+  if (literal->IsUndefined()) return false;
+  if (literal->IsNull()) return false;
+  if (literal->IsString() && String::cast(*literal)->length() == 0) {
+    return false;
+  }
   return true;
 }
 
 void HConstant::PrintDataTo(StringStream* stream) {
-  handle()->ShortPrint(stream);
+  if (has_int32_value_) {
+    stream->Add("%d ", int32_value_);
+  } else if (has_double_value_) {
+    stream->Add("%lf ", double_value_);
+  } else {
+    handle()->ShortPrint(stream);
+  }
 }
 
 
@@ -2089,6 +2134,10 @@ HType HPhi::CalculateInferredType() {
 
 
 HType HConstant::CalculateInferredType() {
+  if (has_int32_value_) {
+    return Smi::IsValid(int32_value_) ? HType::Smi() : HType::HeapNumber();
+  }
+  if (has_double_value_) return HType::HeapNumber();
   return HType::TypeFromValue(handle_);
 }
 

src/hydrogen-instructions.h

@@ -2453,20 +2453,42 @@ class HArgumentsObject: public HTemplateInstruction<0> {
 class HConstant: public HTemplateInstruction<0> {
  public:
   HConstant(Handle<Object> handle, Representation r);
+  HConstant(int32_t value, Representation r);
+  HConstant(double value, Representation r);
 
-  Handle<Object> handle() const { return handle_; }
+  Handle<Object> handle() {
+    if (handle_.is_null()) {
+      handle_ = FACTORY->NewNumber(double_value_, TENURED);
+    }
+    ASSERT(has_int32_value_ || !handle_->IsSmi());
+    return handle_;
+  }
 
   bool InOldSpace() const { return !HEAP->InNewSpace(*handle_); }
 
   bool ImmortalImmovable() const {
+    if (has_int32_value_) {
+      return false;
+    }
+    if (has_double_value_) {
+      if (BitCast<int64_t>(double_value_) == BitCast<int64_t>(-0.0) ||
+          isnan(double_value_)) {
+        return true;
+      }
+      return false;
+    }
+
+    ASSERT(!handle_.is_null());
     Heap* heap = HEAP;
+    // We should have handled minus_zero_value and nan_value in the
+    // has_double_value_ clause above.
+    ASSERT(*handle_ != heap->minus_zero_value());
+    ASSERT(*handle_ != heap->nan_value());
     if (*handle_ == heap->undefined_value()) return true;
     if (*handle_ == heap->null_value()) return true;
     if (*handle_ == heap->true_value()) return true;
     if (*handle_ == heap->false_value()) return true;
     if (*handle_ == heap->the_hole_value()) return true;
-    if (*handle_ == heap->minus_zero_value()) return true;
-    if (*handle_ == heap->nan_value()) return true;
     if (*handle_ == heap->empty_string()) return true;
     return false;
   }
@@ -2476,18 +2498,14 @@ class HConstant: public HTemplateInstruction<0> {
   }
 
   virtual bool IsConvertibleToInteger() const {
-    if (handle_->IsSmi()) return true;
-    if (handle_->IsHeapNumber() &&
-        (HeapNumber::cast(*handle_)->value() ==
-         static_cast<double>(NumberToInt32(*handle_)))) return true;
-    return false;
+    return has_int32_value_;
   }
 
   virtual bool EmitAtUses() { return !representation().IsDouble(); }
   virtual HValue* Canonicalize();
   virtual void PrintDataTo(StringStream* stream);
   virtual HType CalculateInferredType();
-  bool IsInteger() const { return handle_->IsSmi(); }
+  bool IsInteger() { return handle()->IsSmi(); }
   HConstant* CopyToRepresentation(Representation r, Zone* zone) const;
   HConstant* CopyToTruncatedInt32(Zone* zone) const;
   bool HasInteger32Value() const { return has_int32_value_; }
@@ -2500,24 +2518,31 @@ class HConstant: public HTemplateInstruction<0> {
     ASSERT(HasDoubleValue());
     return double_value_;
   }
-  bool HasNumberValue() const { return has_int32_value_ || has_double_value_; }
+  bool HasNumberValue() const { return has_double_value_; }
   int32_t NumberValueAsInteger32() const {
     ASSERT(HasNumberValue());
-    if (has_int32_value_) return int32_value_;
-    return DoubleToInt32(double_value_);
+    // Irrespective of whether a numeric HConstant can be safely
+    // represented as an int32, we store the (in some cases lossy)
+    // representation of the number in int32_value_.
+    return int32_value_;
   }
-  bool HasStringValue() const { return handle_->IsString(); }
 
-  bool ToBoolean() const;
+  bool ToBoolean();
 
   virtual intptr_t Hashcode() {
     ASSERT(!HEAP->allow_allocation(false));
-    intptr_t hash = reinterpret_cast<intptr_t>(*handle());
-    // Prevent smis from having fewer hash values when truncated to
-    // the least significant bits.
-    const int kShiftSize = kSmiShiftSize + kSmiTagSize;
-    STATIC_ASSERT(kShiftSize != 0);
-    return hash ^ (hash >> kShiftSize);
+    intptr_t hash;
+
+    if (has_int32_value_) {
+      hash = static_cast<intptr_t>(int32_value_);
+    } else if (has_double_value_) {
+      hash = static_cast<intptr_t>(BitCast<int64_t>(double_value_));
+    } else {
+      ASSERT(!handle_.is_null());
+      hash = reinterpret_cast<intptr_t>(*handle_);
+    }
+
+    return hash;
   }
 
 #ifdef DEBUG
@@ -2531,15 +2556,32 @@ class HConstant: public HTemplateInstruction<0> {
 
   virtual bool DataEquals(HValue* other) {
     HConstant* other_constant = HConstant::cast(other);
-    return handle().is_identical_to(other_constant->handle());
+    if (has_int32_value_) {
+      return other_constant->has_int32_value_ &&
+          int32_value_ == other_constant->int32_value_;
+    } else if (has_double_value_) {
+      return other_constant->has_double_value_ &&
+          BitCast<int64_t>(double_value_) ==
+          BitCast<int64_t>(other_constant->double_value_);
+    } else {
+      ASSERT(!handle_.is_null());
+      return !other_constant->handle_.is_null() &&
+          *handle_ == *other_constant->handle_;
+    }
   }
 
  private:
+  // If this is a numerical constant, handle_ either points to to the
+  // HeapObject the constant originated from or is null.  If the
+  // constant is non-numeric, handle_ always points to a valid
+  // constant HeapObject.
   Handle<Object> handle_;
 
-  // The following two values represent the int32 and the double value of the
-  // given constant if there is a lossless conversion between the constant
-  // and the specific representation.
+  // We store the HConstant in the most specific form safely possible.
+  // The two flags, has_int32_value_ and has_double_value_ tell us if
+  // int32_value_ and double_value_ hold valid, safe representations
+  // of the constant.  has_int32_value_ implies has_double_value_ but
+  // not the converse.
   bool has_int32_value_ : 1;
   bool has_double_value_ : 1;
   int32_t int32_value_;

src/hydrogen.cc

@@ -579,13 +579,25 @@ HConstant* HGraph::GetConstant(SetOncePointer<HConstant>* pointer,
 }
 
 
+HConstant* HGraph::GetConstantInt32(SetOncePointer<HConstant>* pointer,
+                                    int32_t value) {
+  if (!pointer->is_set()) {
+    HConstant* constant =
+        new(zone()) HConstant(value, Representation::Integer32());
+    constant->InsertAfter(GetConstantUndefined());
+    pointer->set(constant);
+  }
+  return pointer->get();
+}
+
+
 HConstant* HGraph::GetConstant1() {
-  return GetConstant(&constant_1_, Handle<Smi>(Smi::FromInt(1)));
+  return GetConstantInt32(&constant_1_, 1);
 }
 
 
 HConstant* HGraph::GetConstantMinus1() {
-  return GetConstant(&constant_minus1_, Handle<Smi>(Smi::FromInt(-1)));
+  return GetConstantInt32(&constant_minus1_, -1);
 }
 
 
@@ -3378,8 +3390,7 @@ class BoundsCheckBbData: public ZoneObject {
                       Representation representation,
                       int32_t new_offset) {
     HConstant* new_constant = new(BasicBlock()->zone())
-        HConstant(Handle<Object>(Smi::FromInt(new_offset)),
-                  Representation::Integer32());
+       HConstant(new_offset, Representation::Integer32());
     if (*add == NULL) {
       new_constant->InsertBefore(check);
       *add = new(BasicBlock()->zone()) HAdd(NULL,
@@ -7908,8 +7919,8 @@ HInstruction* HGraphBuilder::BuildBinaryOperation(BinaryOperation* expr,
   // for a smi operation. If one of the operands is a constant string
   // do not generate code assuming it is a smi operation.
   if (info.IsSmi() &&
-      ((left->IsConstant() && HConstant::cast(left)->HasStringValue()) ||
-       (right->IsConstant() && HConstant::cast(right)->HasStringValue()))) {
+      ((left->IsConstant() && HConstant::cast(left)->handle()->IsString()) ||
+       (right->IsConstant() && HConstant::cast(right)->handle()->IsString()))) {
     return instr;
   }
   Representation rep = ToRepresentation(info);
@@ -8127,7 +8138,7 @@ static bool MatchLiteralCompareTypeof(HValue* left,
   if (left->IsTypeof() &&
       Token::IsEqualityOp(op) &&
       right->IsConstant() &&
-      HConstant::cast(right)->HasStringValue()) {
+      HConstant::cast(right)->handle()->IsString()) {
     *typeof_expr = HTypeof::cast(left);
     *check = Handle<String>::cast(HConstant::cast(right)->handle());
     return true;

src/hydrogen.h

@@ -348,6 +348,8 @@ class HGraph: public ZoneObject {
  private:
   HConstant* GetConstant(SetOncePointer<HConstant>* pointer,
                          Handle<Object> value);
+  HConstant* GetConstantInt32(SetOncePointer<HConstant>* pointer,
+                              int32_t integer_value);
 
   void MarkAsDeoptimizingRecursively(HBasicBlock* block);
   void InsertTypeConversions(HInstruction* instr);

src/ia32/lithium-codegen-ia32.cc

@@ -360,24 +360,24 @@ XMMRegister LCodeGen::ToDoubleRegister(LOperand* op) const {
 
 
 int LCodeGen::ToInteger32(LConstantOperand* op) const {
-  Handle<Object> value = chunk_->LookupLiteral(op);
+  HConstant* constant = chunk_->LookupConstant(op);
   ASSERT(chunk_->LookupLiteralRepresentation(op).IsInteger32());
-  ASSERT(static_cast<double>(static_cast<int32_t>(value->Number())) ==
-      value->Number());
-  return static_cast<int32_t>(value->Number());
+  ASSERT(constant->HasInteger32Value());
+  return constant->Integer32Value();
 }
 
 
 Handle<Object> LCodeGen::ToHandle(LConstantOperand* op) const {
-  Handle<Object> literal = chunk_->LookupLiteral(op);
+  HConstant* constant = chunk_->LookupConstant(op);
   ASSERT(chunk_->LookupLiteralRepresentation(op).IsTagged());
-  return literal;
+  return constant->handle();
 }
 
 
 double LCodeGen::ToDouble(LConstantOperand* op) const {
-  Handle<Object> value = chunk_->LookupLiteral(op);
-  return value->Number();
+  HConstant* constant = chunk_->LookupConstant(op);
+  ASSERT(constant->HasDoubleValue());
+  return constant->DoubleValue();
 }
 
 
@@ -494,8 +494,8 @@ void LCodeGen::AddToTranslation(Translation* translation,
     XMMRegister reg = ToDoubleRegister(op);
     translation->StoreDoubleRegister(reg);
   } else if (op->IsConstantOperand()) {
-    Handle<Object> literal = chunk()->LookupLiteral(LConstantOperand::cast(op));
-    int src_index = DefineDeoptimizationLiteral(literal);
+    HConstant* constant = chunk()->LookupConstant(LConstantOperand::cast(op));
+    int src_index = DefineDeoptimizationLiteral(constant->handle());
     translation->StoreLiteral(src_index);
   } else {
     UNREACHABLE();
@@ -554,9 +554,9 @@ void LCodeGen::CallRuntimeFromDeferred(Runtime::FunctionId id,
   } else if (context->IsStackSlot()) {
     __ mov(esi, ToOperand(context));
   } else if (context->IsConstantOperand()) {
-    Handle<Object> literal =
-        chunk_->LookupLiteral(LConstantOperand::cast(context));
-    __ LoadHeapObject(esi, Handle<Context>::cast(literal));
+    HConstant* constant =
+        chunk_->LookupConstant(LConstantOperand::cast(context));
+    __ LoadHeapObject(esi, Handle<Context>::cast(constant->handle()));
   } else {
     UNREACHABLE();
   }

src/lithium.cc

@@ -375,8 +375,8 @@ void LChunkBase::AddGapMove(int index, LOperand* from, LOperand* to) {
 }
 
 
-Handle<Object> LChunkBase::LookupLiteral(LConstantOperand* operand) const {
-  return HConstant::cast(graph_->LookupValue(operand->index()))->handle();
+HConstant* LChunkBase::LookupConstant(LConstantOperand* operand) const {
+  return HConstant::cast(graph_->LookupValue(operand->index()));
 }
 
 

src/lithium.h

@@ -639,7 +639,7 @@ class LChunkBase: public ZoneObject {
 
   void AddInstruction(LInstruction* instruction, HBasicBlock* block);
   LConstantOperand* DefineConstantOperand(HConstant* constant);
-  Handle<Object> LookupLiteral(LConstantOperand* operand) const;
+  HConstant* LookupConstant(LConstantOperand* operand) const;
   Representation LookupLiteralRepresentation(LConstantOperand* operand) const;
 
   int ParameterAt(int index);

src/x64/lithium-codegen-x64.cc

@@ -320,24 +320,24 @@ bool LCodeGen::IsTaggedConstant(LConstantOperand* op) const {
 
 
 int LCodeGen::ToInteger32(LConstantOperand* op) const {
-  Handle<Object> value = chunk_->LookupLiteral(op);
+  HConstant* constant = chunk_->LookupConstant(op);
   ASSERT(chunk_->LookupLiteralRepresentation(op).IsInteger32());
-  ASSERT(static_cast<double>(static_cast<int32_t>(value->Number())) ==
-      value->Number());
-  return static_cast<int32_t>(value->Number());
+  ASSERT(constant->HasInteger32Value());
+  return constant->Integer32Value();
 }
 
 
 double LCodeGen::ToDouble(LConstantOperand* op) const {
-  Handle<Object> value = chunk_->LookupLiteral(op);
-  return value->Number();
+  HConstant* constant = chunk_->LookupConstant(op);
+  ASSERT(constant->HasDoubleValue());
+  return constant->DoubleValue();
 }
 
 
 Handle<Object> LCodeGen::ToHandle(LConstantOperand* op) const {
-  Handle<Object> literal = chunk_->LookupLiteral(op);
+  HConstant* constant = chunk_->LookupConstant(op);
   ASSERT(chunk_->LookupLiteralRepresentation(op).IsTagged());
-  return literal;
+  return constant->handle();
 }
 
 
@@ -442,8 +442,8 @@ void LCodeGen::AddToTranslation(Translation* translation,
     XMMRegister reg = ToDoubleRegister(op);
     translation->StoreDoubleRegister(reg);
   } else if (op->IsConstantOperand()) {
-    Handle<Object> literal = chunk()->LookupLiteral(LConstantOperand::cast(op));
-    int src_index = DefineDeoptimizationLiteral(literal);
+    HConstant* constant = chunk()->LookupConstant(LConstantOperand::cast(op));
+    int src_index = DefineDeoptimizationLiteral(constant->handle());
     translation->StoreLiteral(src_index);
   } else {
     UNREACHABLE();