[turbofan] Use special constant type for RPO block number operands.

R=dcarney@chromium.org
BUG=

Review URL: https://codereview.chromium.org/758073002

Cr-Commit-Position: refs/heads/master@{#25508}

src/compiler/arm/code-generator-arm.cc

@@ -77,6 +77,7 @@ class ArmOperandConverter FINAL : public InstructionOperandConverter {
       case Constant::kInt64:
       case Constant::kExternalReference:
       case Constant::kHeapObject:
+      case Constant::kRpoNumber:
         break;
     }
     UNREACHABLE();
@@ -821,6 +822,9 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
         case Constant::kHeapObject:
           __ Move(dst, src.ToHeapObject());
           break;
+        case Constant::kRpoNumber:
+          UNREACHABLE();  // TODO(dcarney): loading RPO constants on arm.
+          break;
       }
       if (destination->IsStackSlot()) __ str(dst, g.ToMemOperand(destination));
     } else if (src.type() == Constant::kFloat32) {

src/compiler/arm64/code-generator-arm64.cc

@@ -142,6 +142,9 @@ class Arm64OperandConverter FINAL : public InstructionOperandConverter {
         return Operand(constant.ToExternalReference());
       case Constant::kHeapObject:
         return Operand(constant.ToHeapObject());
+      case Constant::kRpoNumber:
+        UNREACHABLE();  // TODO(dcarney): RPO immediates on arm64.
+        break;
     }
     UNREACHABLE();
     return Operand(-1);

src/compiler/code-generator-impl.h

@@ -25,6 +25,8 @@ class InstructionOperandConverter {
   InstructionOperandConverter(CodeGenerator* gen, Instruction* instr)
       : gen_(gen), instr_(instr) {}
 
+  // -- Instruction operand accesses with conversions --------------------------
+
   Register InputRegister(int index) {
     return ToRegister(instr_->InputAt(index));
   }
@@ -57,22 +59,31 @@ class InstructionOperandConverter {
     return ToHeapObject(instr_->InputAt(index));
   }
 
-  Label* InputLabel(int index) { return gen_->GetLabel(InputRpo(index)); }
+  Label* InputLabel(int index) { return ToLabel(instr_->InputAt(index)); }
 
   BasicBlock::RpoNumber InputRpo(int index) {
-    int rpo_number = InputInt32(index);
-    return BasicBlock::RpoNumber::FromInt(rpo_number);
+    return ToRpoNumber(instr_->InputAt(index));
   }
 
   Register OutputRegister(int index = 0) {
     return ToRegister(instr_->OutputAt(index));
   }
 
+  Register TempRegister(int index) { return ToRegister(instr_->TempAt(index)); }
+
   DoubleRegister OutputDoubleRegister() {
     return ToDoubleRegister(instr_->Output());
   }
 
-  Register TempRegister(int index) { return ToRegister(instr_->TempAt(index)); }
+  // -- Conversions for operands -----------------------------------------------
+
+  Label* ToLabel(InstructionOperand* op) {
+    return gen_->GetLabel(ToRpoNumber(op));
+  }
+
+  BasicBlock::RpoNumber ToRpoNumber(InstructionOperand* op) {
+    return ToConstant(op).ToRpoNumber();
+  }
 
   Register ToRegister(InstructionOperand* op) {
     DCHECK(op->IsRegister());
@@ -84,19 +95,17 @@ class InstructionOperandConverter {
     return DoubleRegister::FromAllocationIndex(op->index());
   }
 
-  Constant ToConstant(InstructionOperand* operand) {
-    if (operand->IsImmediate()) {
-      return gen_->code()->GetImmediate(operand->index());
+  Constant ToConstant(InstructionOperand* op) {
+    if (op->IsImmediate()) {
+      return gen_->code()->GetImmediate(op->index());
     }
-    return gen_->code()->GetConstant(operand->index());
+    return gen_->code()->GetConstant(op->index());
   }
 
-  double ToDouble(InstructionOperand* operand) {
-    return ToConstant(operand).ToFloat64();
-  }
+  double ToDouble(InstructionOperand* op) { return ToConstant(op).ToFloat64(); }
 
-  Handle<HeapObject> ToHeapObject(InstructionOperand* operand) {
-    return ToConstant(operand).ToHeapObject();
+  Handle<HeapObject> ToHeapObject(InstructionOperand* op) {
+    return ToConstant(op).ToHeapObject();
   }
 
   Frame* frame() const { return gen_->frame(); }

src/compiler/ia32/code-generator-ia32.cc

@@ -69,6 +69,8 @@ class IA32OperandConverter : public InstructionOperandConverter {
         return Immediate(constant.ToHeapObject());
       case Constant::kInt64:
         break;
+      case Constant::kRpoNumber:
+        return Immediate::CodeRelativeOffset(ToLabel(operand));
     }
     UNREACHABLE();
     return Immediate(-1);

src/compiler/instruction-selector-impl.h

@@ -137,8 +137,8 @@ class OperandGenerator {
   }
 
   InstructionOperand* Label(BasicBlock* block) {
-    // TODO(bmeurer): We misuse ImmediateOperand here.
-    return TempImmediate(block->rpo_number());
+    int index = sequence()->AddImmediate(Constant(block->GetRpoNumber()));
+    return ImmediateOperand::Create(index, zone());
   }
 
  protected:

src/compiler/instruction.cc

@@ -332,6 +332,8 @@ std::ostream& operator<<(std::ostream& os, const Constant& constant) {
                        constant.ToExternalReference().address());
     case Constant::kHeapObject:
       return os << Brief(*constant.ToHeapObject());
+    case Constant::kRpoNumber:
+      return os << "RPO" << constant.ToRpoNumber().ToInt();
   }
   UNREACHABLE();
   return os;

src/compiler/instruction.h

@@ -692,7 +692,8 @@ class Constant FINAL {
     kFloat32,
     kFloat64,
     kExternalReference,
-    kHeapObject
+    kHeapObject,
+    kRpoNumber
   };
 
   explicit Constant(int32_t v) : type_(kInt32), value_(v) {}
@@ -703,6 +704,8 @@ class Constant FINAL {
       : type_(kExternalReference), value_(bit_cast<intptr_t>(ref)) {}
   explicit Constant(Handle<HeapObject> obj)
       : type_(kHeapObject), value_(bit_cast<intptr_t>(obj)) {}
+  explicit Constant(BasicBlock::RpoNumber rpo)
+      : type_(kRpoNumber), value_(rpo.ToInt()) {}
 
   Type type() const { return type_; }
 
@@ -735,6 +738,11 @@ class Constant FINAL {
     return bit_cast<ExternalReference>(static_cast<intptr_t>(value_));
   }
 
+  BasicBlock::RpoNumber ToRpoNumber() const {
+    DCHECK_EQ(kRpoNumber, type());
+    return BasicBlock::RpoNumber::FromInt(static_cast<int>(value_));
+  }
+
   Handle<HeapObject> ToHeapObject() const {
     DCHECK_EQ(kHeapObject, type());
     return bit_cast<Handle<HeapObject> >(static_cast<intptr_t>(value_));
@@ -891,7 +899,6 @@ class InstructionBlock FINAL : public ZoneObject {
   PhiInstructions phis_;
   const BasicBlock::Id id_;
   const BasicBlock::RpoNumber ao_number_;  // Assembly order number.
-  // TODO(dcarney): probably dont't need this.
   const BasicBlock::RpoNumber rpo_number_;
   const BasicBlock::RpoNumber loop_header_;
   const BasicBlock::RpoNumber loop_end_;

src/compiler/mips/code-generator-mips.cc

@@ -70,6 +70,9 @@ class MipsOperandConverter FINAL : public InstructionOperandConverter {
         // TODO(plind): Maybe we should handle ExtRef & HeapObj here?
         //    maybe not done on arm due to const pool ??
         break;
+      case Constant::kRpoNumber:
+        UNREACHABLE();  // TODO(titzer): RPO immediates on mips?
+        break;
     }
     UNREACHABLE();
     return Operand(zero_reg);
@@ -796,6 +799,9 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
         case Constant::kHeapObject:
           __ li(dst, src.ToHeapObject());
           break;
+        case Constant::kRpoNumber:
+          UNREACHABLE();  // TODO(titzer): loading RPO numbers on mips.
+          break;
       }
       if (destination->IsStackSlot()) __ sw(dst, g.ToMemOperand(destination));
     } else if (src.type() == Constant::kFloat32) {

src/compiler/mips64/code-generator-mips64.cc

@@ -71,6 +71,9 @@ class MipsOperandConverter FINAL : public InstructionOperandConverter {
         // TODO(plind): Maybe we should handle ExtRef & HeapObj here?
         //    maybe not done on arm due to const pool ??
         break;
+      case Constant::kRpoNumber:
+        UNREACHABLE();  // TODO(titzer): RPO immediates on mips?
+        break;
     }
     UNREACHABLE();
     return Operand(zero_reg);
@@ -1071,6 +1074,9 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
         case Constant::kHeapObject:
           __ li(dst, src.ToHeapObject());
           break;
+        case Constant::kRpoNumber:
+          UNREACHABLE();  // TODO(titzer): loading RPO numbers on mips64.
+          break;
       }
       if (destination->IsStackSlot()) __ sd(dst, g.ToMemOperand(destination));
     } else if (src.type() == Constant::kFloat32) {

src/compiler/x64/code-generator-x64.cc

@@ -919,6 +919,9 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
         case Constant::kHeapObject:
           __ Move(dst, src.ToHeapObject());
           break;
+        case Constant::kRpoNumber:
+          UNREACHABLE();  // TODO(dcarney): load of labels on x64.
+          break;
       }
       if (destination->IsStackSlot()) {
         __ movq(g.ToOperand(destination), kScratchRegister);