Revert of [Interpreter] Optimize BytecodeArrayBuilder and BytecodeArrayWriter.

src/interpreter/bytecode-array-writer.cc

Index: src/interpreter/bytecode-array-writer.cc
diff --git a/src/interpreter/bytecode-array-writer.cc b/src/interpreter/bytecode-array-writer.cc
index 02948dc5af895c445f79eb775e933adb86ee71a3..93db4530165686b6f8cf9954f5267c5f1bdd9647 100644
--- a/src/interpreter/bytecode-array-writer.cc
+++ b/src/interpreter/bytecode-array-writer.cc
@@ -21,23 +21,27 @@
     Zone* zone, ConstantArrayBuilder* constant_array_builder,
     SourcePositionTableBuilder::RecordingMode source_position_mode)
     : bytecodes_(zone),
+      max_register_count_(0),
       unbound_jumps_(0),
       source_position_table_builder_(zone, source_position_mode),
-      constant_array_builder_(constant_array_builder) {
-  bytecodes_.reserve(512);  // Derived via experimentation.
-}
+      constant_array_builder_(constant_array_builder) {}
 
 // override
 BytecodeArrayWriter::~BytecodeArrayWriter() {}
 
 // override
 Handle<BytecodeArray> BytecodeArrayWriter::ToBytecodeArray(
-    Isolate* isolate, int register_count, int parameter_count,
+    Isolate* isolate, int fixed_register_count, int parameter_count,
     Handle<FixedArray> handler_table) {
   DCHECK_EQ(0, unbound_jumps_);
 
   int bytecode_size = static_cast<int>(bytecodes()->size());
-  int frame_size = register_count * kPointerSize;
+
+  // All locals need a frame slot for the debugger, but may not be
+  // present in generated code.
+  int frame_size_for_locals = fixed_register_count * kPointerSize;
+  int frame_size_used = max_register_count() * kPointerSize;
+  int frame_size = std::max(frame_size_for_locals, frame_size_used);
   Handle<FixedArray> constant_pool =
       constant_array_builder()->ToFixedArray(isolate);
   Handle<BytecodeArray> bytecode_array = isolate->factory()->NewBytecodeArray(
@@ -100,48 +104,116 @@
   }
 }
 
+namespace {
+
+OperandScale ScaleForScalableByteOperand(OperandSize operand_size) {
+  STATIC_ASSERT(static_cast<int>(OperandSize::kByte) ==
+                static_cast<int>(OperandScale::kSingle));
+  STATIC_ASSERT(static_cast<int>(OperandSize::kShort) ==
+                static_cast<int>(OperandScale::kDouble));
+  STATIC_ASSERT(static_cast<int>(OperandSize::kQuad) ==
+                static_cast<int>(OperandScale::kQuadruple));
+  return static_cast<OperandScale>(operand_size);
+}
+
+OperandScale OperandScaleForScalableSignedByte(uint32_t operand_value) {
+  int32_t signed_operand = static_cast<int32_t>(operand_value);
+  OperandSize bytes_required = Bytecodes::SizeForSignedOperand(signed_operand);
+  return ScaleForScalableByteOperand(bytes_required);
+}
+
+OperandScale OperandScaleForScalableUnsignedByte(uint32_t operand_value) {
+  OperandSize bytes_required = Bytecodes::SizeForUnsignedOperand(operand_value);
+  return ScaleForScalableByteOperand(bytes_required);
+}
+
+OperandScale GetOperandScale(const BytecodeNode* const node) {
+  const OperandTypeInfo* operand_type_infos =
+      Bytecodes::GetOperandTypeInfos(node->bytecode());
+  OperandScale operand_scale = OperandScale::kSingle;
+  int operand_count = node->operand_count();
+  for (int i = 0; i < operand_count; ++i) {
+    switch (operand_type_infos[i]) {
+      case OperandTypeInfo::kScalableSignedByte: {
+        uint32_t operand = node->operand(i);
+        operand_scale =
+            std::max(operand_scale, OperandScaleForScalableSignedByte(operand));
+        break;
+      }
+      case OperandTypeInfo::kScalableUnsignedByte: {
+        uint32_t operand = node->operand(i);
+        operand_scale = std::max(operand_scale,
+                                 OperandScaleForScalableUnsignedByte(operand));
+        break;
+      }
+      case OperandTypeInfo::kFixedUnsignedByte:
+      case OperandTypeInfo::kFixedUnsignedShort:
+        break;
+      case OperandTypeInfo::kNone:
+        UNREACHABLE();
+        break;
+    }
+  }
+  return operand_scale;
+}
+
+}  // namespace
+
 void BytecodeArrayWriter::EmitBytecode(const BytecodeNode* const node) {
   DCHECK_NE(node->bytecode(), Bytecode::kIllegal);
 
-  Bytecode bytecode = node->bytecode();
-  OperandScale operand_scale = node->operand_scale();
-
+  uint8_t buffer[kMaxSizeOfPackedBytecode];
+  uint8_t* buffer_limit = buffer;
+
+  OperandScale operand_scale = GetOperandScale(node);
   if (operand_scale != OperandScale::kSingle) {
     Bytecode prefix = Bytecodes::OperandScaleToPrefixBytecode(operand_scale);
-    bytecodes()->push_back(Bytecodes::ToByte(prefix));
-  }
-  bytecodes()->push_back(Bytecodes::ToByte(bytecode));
+    *buffer_limit++ = Bytecodes::ToByte(prefix);
+  }
+
+  Bytecode bytecode = node->bytecode();
+  *buffer_limit++ = Bytecodes::ToByte(bytecode);
 
   const uint32_t* const operands = node->operands();
-  const int operand_count = node->operand_count();
-  const OperandSize* operand_sizes =
-      Bytecodes::GetOperandSizes(bytecode, operand_scale);
+  const OperandType* operand_types = Bytecodes::GetOperandTypes(bytecode);
+  const int operand_count = Bytecodes::NumberOfOperands(bytecode);
   for (int i = 0; i < operand_count; ++i) {
-    switch (operand_sizes[i]) {
+    OperandSize operand_size =
+        Bytecodes::SizeOfOperand(operand_types[i], operand_scale);
+    switch (operand_size) {
       case OperandSize::kNone:
         UNREACHABLE();
         break;
       case OperandSize::kByte:
-        bytecodes()->push_back(static_cast<uint8_t>(operands[i]));
+        *buffer_limit++ = static_cast<uint8_t>(operands[i]);
         break;
       case OperandSize::kShort: {
-        const uint8_t* raw_operand =
-            reinterpret_cast<const uint8_t*>(&operands[i]);
-        bytecodes()->push_back(raw_operand[0]);
-        bytecodes()->push_back(raw_operand[1]);
+        WriteUnalignedUInt16(buffer_limit, operands[i]);
+        buffer_limit += 2;
         break;
       }
       case OperandSize::kQuad: {
-        const uint8_t* raw_operand =
-            reinterpret_cast<const uint8_t*>(&operands[i]);
-        bytecodes()->push_back(raw_operand[0]);
-        bytecodes()->push_back(raw_operand[1]);
-        bytecodes()->push_back(raw_operand[2]);
-        bytecodes()->push_back(raw_operand[3]);
+        WriteUnalignedUInt32(buffer_limit, operands[i]);
+        buffer_limit += 4;
         break;
       }
     }
-  }
+
+    int count = Bytecodes::GetNumberOfRegistersRepresentedBy(operand_types[i]);
+    if (count == 0) {
+      continue;
+    }
+    // NB operand_types is terminated by OperandType::kNone so
+    // operand_types[i + 1] is valid whilst i < operand_count.
+    if (operand_types[i + 1] == OperandType::kRegCount) {
+      count = static_cast<int>(operands[i]);
+    }
+    Register reg = Register::FromOperand(static_cast<int32_t>(operands[i]));
+    max_register_count_ = std::max(max_register_count_, reg.index() + count);
+  }
+
+  DCHECK_LE(buffer_limit, buffer + sizeof(buffer));
+  bytecodes()->insert(bytecodes()->end(), buffer, buffer_limit);
 }
 
 // static
@@ -175,17 +247,18 @@
   DCHECK(Bytecodes::IsJumpImmediate(jump_bytecode));
   size_t operand_location = jump_location + 1;
   DCHECK_EQ(bytecodes()->at(operand_location), k8BitJumpPlaceholder);
-  if (Bytecodes::ScaleForSignedOperand(delta) == OperandScale::kSingle) {
-    // The jump fits within the range of an Imm8 operand, so cancel
+  if (Bytecodes::SizeForSignedOperand(delta) == OperandSize::kByte) {
+    // The jump fits within the range of an Imm operand, so cancel
     // the reservation and jump directly.
     constant_array_builder()->DiscardReservedEntry(OperandSize::kByte);
     bytecodes()->at(operand_location) = static_cast<uint8_t>(delta);
   } else {
-    // The jump does not fit within the range of an Imm8 operand, so
+    // The jump does not fit within the range of an Imm operand, so
     // commit reservation putting the offset into the constant pool,
     // and update the jump instruction and operand.
     size_t entry = constant_array_builder()->CommitReservedEntry(
         OperandSize::kByte, Smi::FromInt(delta));
+    DCHECK_LE(entry, kMaxUInt32);
     DCHECK_EQ(Bytecodes::SizeForUnsignedOperand(static_cast<uint32_t>(entry)),
               OperandSize::kByte);
     jump_bytecode = GetJumpWithConstantOperand(jump_bytecode);
@@ -200,21 +273,14 @@
   DCHECK(Bytecodes::IsJumpImmediate(jump_bytecode));
   size_t operand_location = jump_location + 1;
   uint8_t operand_bytes[2];
-  if (Bytecodes::ScaleForSignedOperand(delta) <= OperandScale::kDouble) {
-    // The jump fits within the range of an Imm16 operand, so cancel
-    // the reservation and jump directly.
+  if (Bytecodes::SizeForSignedOperand(delta) <= OperandSize::kShort) {
     constant_array_builder()->DiscardReservedEntry(OperandSize::kShort);
     WriteUnalignedUInt16(operand_bytes, static_cast<uint16_t>(delta));
   } else {
-    // The jump does not fit within the range of an Imm16 operand, so
-    // commit reservation putting the offset into the constant pool,
-    // and update the jump instruction and operand.
+    jump_bytecode = GetJumpWithConstantOperand(jump_bytecode);
+    bytecodes()->at(jump_location) = Bytecodes::ToByte(jump_bytecode);
     size_t entry = constant_array_builder()->CommitReservedEntry(
         OperandSize::kShort, Smi::FromInt(delta));
-    DCHECK_EQ(Bytecodes::SizeForUnsignedOperand(static_cast<uint32_t>(entry)),
-              OperandSize::kShort);
-    jump_bytecode = GetJumpWithConstantOperand(jump_bytecode);
-    bytecodes()->at(jump_location) = Bytecodes::ToByte(jump_bytecode);
     WriteUnalignedUInt16(operand_bytes, static_cast<uint16_t>(entry));
   }
   DCHECK(bytecodes()->at(operand_location) == k8BitJumpPlaceholder &&
@@ -285,8 +351,8 @@
     // Label has been bound already so this is a backwards jump.
     size_t abs_delta = current_offset - label->offset();
     int delta = -static_cast<int>(abs_delta);
-    OperandScale operand_scale = Bytecodes::ScaleForSignedOperand(delta);
-    if (operand_scale > OperandScale::kSingle) {
+    OperandSize operand_size = Bytecodes::SizeForSignedOperand(delta);
+    if (operand_size > OperandSize::kByte) {
       // Adjust for scaling byte prefix for wide jump offset.
       DCHECK_LE(delta, 0);
       delta -= 1;