Improve and simplify removal of unreachable code

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 85 matching lines @@
   info()->CommitDependencies(code);
 }
 
 
 void LChunkBuilder::Abort(BailoutReason reason) {
   info()->set_bailout_reason(reason);
   status_ = ABORTED;
 }
 
 
-void LCodeGen::Comment(const char* format, ...) {
-  if (!FLAG_code_comments) return;
-  char buffer[4 * KB];
-  StringBuilder builder(buffer, ARRAY_SIZE(buffer));
-  va_list arguments;
-  va_start(arguments, format);
-  builder.AddFormattedList(format, arguments);
-  va_end(arguments);
-
-  // Copy the string before recording it in the assembler to avoid
-  // issues when the stack allocated buffer goes out of scope.
-  int length = builder.position();
-  Vector<char> copy = Vector<char>::New(length + 1);
-  OS::MemCopy(copy.start(), builder.Finalize(), copy.length());
-  masm()->RecordComment(copy.start());
-}
-
-
 #ifdef _MSC_VER
 void LCodeGen::MakeSureStackPagesMapped(int offset) {
   const int kPageSize = 4 * KB;
   for (offset -= kPageSize; offset > 0; offset -= kPageSize) {
     __ movq(Operand(rsp, offset), rax);
   }
 }
 #endif
 
 
@@ skipping 132 matching lines @@
   osr_pc_offset_ = masm()->pc_offset();
 
   // Adjust the frame size, subsuming the unoptimized frame into the
   // optimized frame.
   int slots = GetStackSlotCount() - graph()->osr()->UnoptimizedFrameSlots();
   ASSERT(slots >= 0);
   __ subq(rsp, Immediate(slots * kPointerSize));
 }
 
 
-bool LCodeGen::GenerateBody() {
-  ASSERT(is_generating());
-  bool emit_instructions = true;
-  for (current_instruction_ = 0;
-       !is_aborted() && current_instruction_ < instructions_->length();
-       current_instruction_++) {
-    LInstruction* instr = instructions_->at(current_instruction_);
-
-    // Don't emit code for basic blocks with a replacement.
-    if (instr->IsLabel()) {
-      emit_instructions = !LLabel::cast(instr)->HasReplacement();
-    }
-    if (!emit_instructions) continue;
-
-    if (FLAG_code_comments && instr->HasInterestingComment(this)) {
-      Comment(";;; <@%d,#%d> %s",
-              current_instruction_,
-              instr->hydrogen_value()->id(),
-              instr->Mnemonic());
-    }
-
-    RecordAndUpdatePosition(instr->position());
-
-    instr->CompileToNative(this);
-  }
-  EnsureSpaceForLazyDeopt(Deoptimizer::patch_size());
-  return !is_aborted();
-}
-
-
 bool LCodeGen::GenerateJumpTable() {
   Label needs_frame;
   if (jump_table_.length() > 0) {
     Comment(";;; -------------------- Jump table --------------------");
   }
   for (int i = 0; i < jump_table_.length(); i++) {
     __ bind(&jump_table_[i].label);
     Address entry = jump_table_[i].address;
     Deoptimizer::BailoutType type = jump_table_[i].bailout_type;
     int id = Deoptimizer::GetDeoptimizationId(isolate(), entry, type);
@@ skipping 1581 matching lines @@
   ASSERT(ToRegister(instr->left()).is(rdx));
   ASSERT(ToRegister(instr->right()).is(rax));
   ASSERT(ToRegister(instr->result()).is(rax));
 
   BinaryOpStub stub(instr->op(), NO_OVERWRITE);
   CallCode(stub.GetCode(isolate()), RelocInfo::CODE_TARGET, instr);
   __ nop();  // Signals no inlined code.
 }
 
 
-int LCodeGen::GetNextEmittedBlock() const {
-  for (int i = current_block_ + 1; i < graph()->blocks()->length(); ++i) {
-    if (!chunk_->GetLabel(i)->HasReplacement()) return i;
-  }
-  return -1;
-}
-
-
 template<class InstrType>
 void LCodeGen::EmitBranch(InstrType instr, Condition cc) {
   int left_block = instr->TrueDestination(chunk_);
   int right_block = instr->FalseDestination(chunk_);
 
   int next_block = GetNextEmittedBlock();
 
   if (right_block == left_block || cc == no_condition) {
     EmitGoto(left_block);
   } else if (left_block == next_block) {
@@ skipping 3589 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64