[Interpreter] Make dispatch table point to code entry instead of code objects.

src/interpreter/interpreter.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/interpreter.h"
 
 #include <fstream>
 
 #include "src/ast/prettyprinter.h"
 #include "src/code-factory.h"
@@ skipping 36 matching lines @@
        operand_scale <= OperandScale::kMaxValid;
        operand_scale = Bytecodes::NextOperandScale(operand_scale)) {
 #define GENERATE_CODE(Name, ...)                                               \
   {                                                                            \
     if (Bytecodes::BytecodeHasHandler(Bytecode::k##Name, operand_scale)) {     \
       InterpreterAssembler assembler(isolate_, &zone, Bytecode::k##Name,       \
                                      operand_scale);                           \
       Do##Name(&assembler);                                                    \
       Handle<Code> code = assembler.GenerateCode();                            \
       size_t index = GetDispatchTableIndex(Bytecode::k##Name, operand_scale);  \
-      dispatch_table_[index] = *code;                                          \
+      dispatch_table_[index] = code->entry();                                  \
       TraceCodegen(code);                                                      \
       LOG_CODE_EVENT(                                                          \
           isolate_,                                                            \
           CodeCreateEvent(                                                     \
               Logger::BYTECODE_HANDLER_TAG, AbstractCode::cast(*code),         \
               Bytecodes::ToString(Bytecode::k##Name, operand_scale).c_str())); \
     }                                                                          \
   }
     BYTECODE_LIST(GENERATE_CODE)
 #undef GENERATE_CODE
   }
 
   // Fill unused entries will the illegal bytecode handler.
   size_t illegal_index =
       GetDispatchTableIndex(Bytecode::kIllegal, OperandScale::kSingle);
   for (size_t index = 0; index < arraysize(dispatch_table_); ++index) {
     if (dispatch_table_[index] == nullptr) {
       dispatch_table_[index] = dispatch_table_[illegal_index];
     }
   }
 }
 
 Code* Interpreter::GetBytecodeHandler(Bytecode bytecode,
                                       OperandScale operand_scale) {
   DCHECK(IsDispatchTableInitialized());
   DCHECK(Bytecodes::BytecodeHasHandler(bytecode, operand_scale));
   size_t index = GetDispatchTableIndex(bytecode, operand_scale);
-  return dispatch_table_[index];
+  Address code_entry = dispatch_table_[index];
+  return Code::GetCodeFromTargetAddress(code_entry);
 }
 
 // static
 size_t Interpreter::GetDispatchTableIndex(Bytecode bytecode,
                                           OperandScale operand_scale) {
   static const size_t kEntriesPerOperandScale = 1u << kBitsPerByte;
   size_t index = static_cast<size_t>(bytecode);
   OperandScale current_scale = OperandScale::kSingle;
   while (current_scale != operand_scale) {
     index += kEntriesPerOperandScale;
     current_scale = Bytecodes::NextOperandScale(current_scale);
   }
   return index;
 }
 
 void Interpreter::IterateDispatchTable(ObjectVisitor* v) {
-  v->VisitPointers(
-      reinterpret_cast<Object**>(&dispatch_table_[0]),
-      reinterpret_cast<Object**>(&dispatch_table_[0] + kDispatchTableSize));
+  for (int i = 0; i < kDispatchTableSize; i++) {
+    Address code_entry = dispatch_table_[i];
+    Object* code = code_entry == nullptr
+                       ? nullptr
+                       : Code::GetCodeFromTargetAddress(code_entry);
+    Object* old_code = code;
+    v->VisitPointer(&code);
+    if (code != old_code) {
+      dispatch_table_[i] = reinterpret_cast<Code*>(code)->entry();
+    }
+  }
 }
 
 // static
 int Interpreter::InterruptBudget() {
   // TODO(ignition): Tune code size multiplier.
   const int kCodeSizeMultiplier = 32;
   return FLAG_interrupt_budget * kCodeSizeMultiplier;
 }
 
 bool Interpreter::MakeBytecode(CompilationInfo* info) {
@@ skipping 57 matching lines @@
   if (FLAG_trace_ignition_codegen) {
     OFStream os(stdout);
     code->Disassemble(nullptr, os);
     os << std::flush;
   }
 #endif  // ENABLE_DISASSEMBLER
 }
 
 const char* Interpreter::LookupNameOfBytecodeHandler(Code* code) {
 #ifdef ENABLE_DISASSEMBLER
-#define RETURN_NAME(Name, ...)                                         \
-  if (dispatch_table_[Bytecodes::ToByte(Bytecode::k##Name)] == code) { \
-    return #Name;                                                      \
+#define RETURN_NAME(Name, ...)                                 \
+  if (dispatch_table_[Bytecodes::ToByte(Bytecode::k##Name)] == \
+      code->entry()) {                                         \
+    return #Name;                                              \
   }
   BYTECODE_LIST(RETURN_NAME)
 #undef RETURN_NAME
 #endif  // ENABLE_DISASSEMBLER
   return nullptr;
 }
 
 void Interpreter::WriteDispatchCounters() {
   std::ofstream stream(FLAG_trace_ignition_dispatches_output_file);
   static const int kBytecodeCount = static_cast<int>(Bytecode::kLast) + 1;
@@ skipping 1476 matching lines @@
 // Illegal
 //
 // An invalid bytecode aborting execution if dispatched.
 void Interpreter::DoIllegal(InterpreterAssembler* assembler) {
   __ Abort(kInvalidBytecode);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8