[interpreter] Encode BytecodeSizes as uint8_t for better cache locality

This very slightly improves the performance of bytecode array visitors.

Change-Id: I39df381a26106b5576df74c8c204279b224a92af
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2653227
Auto-Submit: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72387}

src/builtins/arm/builtins-arm.cc

@@ -942,11 +942,11 @@ static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
 
   // Update table to the wide scaled table.
   __ add(bytecode_size_table, bytecode_size_table,
-         Operand(kIntSize * interpreter::Bytecodes::kBytecodeCount));
+         Operand(kByteSize * interpreter::Bytecodes::kBytecodeCount));
   // Conditionally update table to the extra wide scaled table. We are taking
   // advantage of the fact that the extra wide follows the wide one.
   __ add(bytecode_size_table, bytecode_size_table,
-         Operand(kIntSize * interpreter::Bytecodes::kBytecodeCount), LeaveCC,
+         Operand(kByteSize * interpreter::Bytecodes::kBytecodeCount), LeaveCC,
          ne);
 
   __ bind(&process_bytecode);
@@ -976,7 +976,7 @@ static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
 
   __ bind(&not_jump_loop);
   // Otherwise, load the size of the current bytecode and advance the offset.
-  __ ldr(scratch1, MemOperand(bytecode_size_table, bytecode, LSL, 2));
+  __ ldrb(scratch1, MemOperand(bytecode_size_table, bytecode));
   __ add(bytecode_offset, bytecode_offset, scratch1);
 
   __ bind(&end);

src/builtins/arm64/builtins-arm64.cc

@@ -1112,13 +1112,13 @@ static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
 
   // Update table to the wide scaled table.
   __ Add(bytecode_size_table, bytecode_size_table,
-         Operand(kIntSize * interpreter::Bytecodes::kBytecodeCount));
+         Operand(kByteSize * interpreter::Bytecodes::kBytecodeCount));
   __ B(&process_bytecode);
 
   __ Bind(&extra_wide);
   // Update table to the extra wide scaled table.
   __ Add(bytecode_size_table, bytecode_size_table,
-         Operand(2 * kIntSize * interpreter::Bytecodes::kBytecodeCount));
+         Operand(2 * kByteSize * interpreter::Bytecodes::kBytecodeCount));
 
   __ Bind(&process_bytecode);
 
@@ -1141,7 +1141,7 @@ static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
 
   __ bind(&not_jump_loop);
   // Otherwise, load the size of the current bytecode and advance the offset.
-  __ Ldr(scratch1.W(), MemOperand(bytecode_size_table, bytecode, LSL, 2));
+  __ Ldrb(scratch1.W(), MemOperand(bytecode_size_table, bytecode));
   __ Add(bytecode_offset, bytecode_offset, scratch1);
 
   __ Bind(&end);

src/builtins/ia32/builtins-ia32.cc

@@ -874,13 +874,13 @@ static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
 
   // Load the next bytecode and update table to the wide scaled table.
   __ add(bytecode_size_table,
-         Immediate(kIntSize * interpreter::Bytecodes::kBytecodeCount));
+         Immediate(kByteSize * interpreter::Bytecodes::kBytecodeCount));
   __ jmp(&process_bytecode, Label::kNear);
 
   __ bind(&extra_wide);
   // Update table to the extra wide scaled table.
   __ add(bytecode_size_table,
-         Immediate(2 * kIntSize * interpreter::Bytecodes::kBytecodeCount));
+         Immediate(2 * kByteSize * interpreter::Bytecodes::kBytecodeCount));
 
   __ bind(&process_bytecode);
 
@@ -906,8 +906,9 @@ static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
 
   __ bind(&not_jump_loop);
   // Otherwise, load the size of the current bytecode and advance the offset.
-  __ add(bytecode_offset,
-         Operand(bytecode_size_table, bytecode, times_int_size, 0));
+  __ movzx_b(bytecode_size_table,
+             Operand(bytecode_size_table, bytecode, times_1, 0));
+  __ add(bytecode_offset, bytecode_size_table);
 
   __ bind(&end);
 }

src/builtins/x64/builtins-x64.cc

@@ -976,13 +976,13 @@ static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
 
   // Update table to the wide scaled table.
   __ addq(bytecode_size_table,
-          Immediate(kIntSize * interpreter::Bytecodes::kBytecodeCount));
+          Immediate(kByteSize * interpreter::Bytecodes::kBytecodeCount));
   __ jmp(&process_bytecode, Label::kNear);
 
   __ bind(&extra_wide);
   // Update table to the extra wide scaled table.
   __ addq(bytecode_size_table,
-          Immediate(2 * kIntSize * interpreter::Bytecodes::kBytecodeCount));
+          Immediate(2 * kByteSize * interpreter::Bytecodes::kBytecodeCount));
 
   __ bind(&process_bytecode);
 
@@ -1007,8 +1007,9 @@ static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
 
   __ bind(&not_jump_loop);
   // Otherwise, load the size of the current bytecode and advance the offset.
-  __ addl(bytecode_offset,
-          Operand(bytecode_size_table, bytecode, times_int_size, 0));
+  __ movzxbl(kScratchRegister,
+             Operand(bytecode_size_table, bytecode, times_1, 0));
+  __ addl(bytecode_offset, kScratchRegister);
 
   __ bind(&end);
 }

src/interpreter/bytecodes.cc

@@ -38,7 +38,7 @@ const AccumulatorUse Bytecodes::kAccumulatorUse[] = {
 #undef ENTRY
 };
 
-const int Bytecodes::kBytecodeSizes[3][kBytecodeCount] = {
+const uint8_t Bytecodes::kBytecodeSizes[3][kBytecodeCount] = {
   {
 #define ENTRY(Name, ...) BytecodeTraits<__VA_ARGS__>::kSingleScaleSize,
   BYTECODE_LIST(ENTRY)

src/interpreter/bytecodes.h

@@ -934,7 +934,8 @@ class V8_EXPORT_PRIVATE Bytecodes final : public AllStatic {
   }
 
   static Address bytecode_size_table_address() {
-    return reinterpret_cast<Address>(const_cast<int*>(&kBytecodeSizes[0][0]));
+    return reinterpret_cast<Address>(
+        const_cast<uint8_t*>(&kBytecodeSizes[0][0]));
   }
 
  private:
@@ -944,7 +945,7 @@ class V8_EXPORT_PRIVATE Bytecodes final : public AllStatic {
   static const int kNumberOfRegisterOperands[];
   static const AccumulatorUse kAccumulatorUse[];
   static const bool kIsScalable[];
-  static const int kBytecodeSizes[3][kBytecodeCount];
+  static const uint8_t kBytecodeSizes[3][kBytecodeCount];
   static const OperandSize* const kOperandSizes[3][kBytecodeCount];
   static OperandSize const
       kOperandKindSizes[3][BytecodeOperands::kOperandTypeCount];