Improve and simplify removal of unreachable code

src/arm/lithium-codegen-arm.h

 // Copyright 2012 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 14 matching lines @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_ARM_LITHIUM_CODEGEN_ARM_H_
 #define V8_ARM_LITHIUM_CODEGEN_ARM_H_
 
 #include "arm/lithium-arm.h"
 
 #include "arm/lithium-gap-resolver-arm.h"
 #include "deoptimizer.h"
+#include "lithium-codegen.h"
 #include "safepoint-table.h"
 #include "scopes.h"
 #include "v8utils.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
 class LDeferredCode;
 class SafepointGenerator;
 
-class LCodeGen V8_FINAL BASE_EMBEDDED {
+class LCodeGen: public LCodeGenBase {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)
-      : zone_(info->zone()),
-        chunk_(static_cast<LPlatformChunk*>(chunk)),
-        masm_(assembler),
-        info_(info),
-        current_block_(-1),
-        current_instruction_(-1),
-        instructions_(chunk->instructions()),
+      : LCodeGenBase(chunk, assembler, info),
         deoptimizations_(4, info->zone()),
         deopt_jump_table_(4, info->zone()),
         deoptimization_literals_(8, info->zone()),
         inlined_function_count_(0),
         scope_(info->scope()),
-        status_(UNUSED),
         translations_(info->zone()),
         deferred_(8, info->zone()),
         osr_pc_offset_(-1),
-        last_lazy_deopt_pc_(0),
         frame_is_built_(false),
         safepoints_(info->zone()),
         resolver_(this),
         expected_safepoint_kind_(Safepoint::kSimple),
         old_position_(RelocInfo::kNoPosition) {
     PopulateDeoptimizationLiteralsWithInlinedFunctions();
   }
 
 
-  // Simple accessors.
-  MacroAssembler* masm() const { return masm_; }
-  CompilationInfo* info() const { return info_; }
-  Isolate* isolate() const { return info_->isolate(); }
-  Factory* factory() const { return isolate()->factory(); }
-  Heap* heap() const { return isolate()->heap(); }
-  Zone* zone() const { return zone_; }
-
   int LookupDestination(int block_id) const {
     return chunk()->LookupDestination(block_id);
   }
 
   bool IsNextEmittedBlock(int block_id) const {
     return LookupDestination(block_id) == GetNextEmittedBlock();
   }
 
   bool NeedsEagerFrame() const {
     return GetStackSlotCount() > 0 ||
@@ skipping 78 matching lines @@
 
   // Emit frame translation commands for an environment.
   void WriteTranslation(LEnvironment* environment, Translation* translation);
 
   // Declare methods that deal with the individual node types.
 #define DECLARE_DO(type) void Do##type(L##type* node);
   LITHIUM_CONCRETE_INSTRUCTION_LIST(DECLARE_DO)
 #undef DECLARE_DO
 
  private:
-  enum Status {
-    UNUSED,
-    GENERATING,
-    DONE,
-    ABORTED
-  };
-
-  bool is_unused() const { return status_ == UNUSED; }
-  bool is_generating() const { return status_ == GENERATING; }
-  bool is_done() const { return status_ == DONE; }
-  bool is_aborted() const { return status_ == ABORTED; }
-
   StrictModeFlag strict_mode_flag() const {
     return info()->is_classic_mode() ? kNonStrictMode : kStrictMode;
   }
 
-  LPlatformChunk* chunk() const { return chunk_; }
   Scope* scope() const { return scope_; }
-  HGraph* graph() const { return chunk()->graph(); }
 
   Register scratch0() { return r9; }
   LowDwVfpRegister double_scratch0() { return kScratchDoubleReg; }
 
-  int GetNextEmittedBlock() const;
   LInstruction* GetNextInstruction();
 
   void EmitClassOfTest(Label* if_true,
                        Label* if_false,
                        Handle<String> class_name,
                        Register input,
                        Register temporary,
                        Register temporary2);
 
   int GetStackSlotCount() const { return chunk()->spill_slot_count(); }
 
   void Abort(BailoutReason reason);
-  void FPRINTF_CHECKING Comment(const char* format, ...);
 
   void AddDeferredCode(LDeferredCode* code) { deferred_.Add(code, zone()); }
 
   // Code generation passes.  Returns true if code generation should
   // continue.
   bool GeneratePrologue();
-  bool GenerateBody();
   bool GenerateDeferredCode();
   bool GenerateDeoptJumpTable();
   bool GenerateSafepointTable();
 
   // Generates the custom OSR entrypoint and sets the osr_pc_offset.
   void GenerateOsrPrologue();
 
   enum SafepointMode {
     RECORD_SIMPLE_SAFEPOINT,
     RECORD_SAFEPOINT_WITH_REGISTERS_AND_NO_ARGUMENTS
@@ skipping 81 matching lines @@
                        Safepoint::DeoptMode mode);
   void RecordSafepoint(LPointerMap* pointers, Safepoint::DeoptMode mode);
   void RecordSafepoint(Safepoint::DeoptMode mode);
   void RecordSafepointWithRegisters(LPointerMap* pointers,
                                     int arguments,
                                     Safepoint::DeoptMode mode);
   void RecordSafepointWithRegistersAndDoubles(LPointerMap* pointers,
                                               int arguments,
                                               Safepoint::DeoptMode mode);
   void RecordPosition(int position);
-  void RecordAndUpdatePosition(int position);
+  void RecordAndUpdatePosition(int position) V8_OVERRIDE;
 
   static Condition TokenToCondition(Token::Value op, bool is_unsigned);
   void EmitGoto(int block);
   template<class InstrType>
   void EmitBranch(InstrType instr, Condition condition);
   template<class InstrType>
   void EmitFalseBranch(InstrType instr, Condition condition);
   void EmitNumberUntagD(Register input,
                         DwVfpRegister result,
                         bool allow_undefined_as_nan,
@@ skipping 41 matching lines @@
   // Inputs are signed.
   // All registers are clobbered.
   // If 'remainder' is no_reg, it is not computed.
   void EmitSignedIntegerDivisionByConstant(Register result,
                                            Register dividend,
                                            int32_t divisor,
                                            Register remainder,
                                            Register scratch,
                                            LEnvironment* environment);
 
-  void EnsureSpaceForLazyDeopt();
+  void EnsureSpaceForLazyDeopt(int space_needed) V8_OVERRIDE;
   void DoLoadKeyedExternalArray(LLoadKeyed* instr);
   void DoLoadKeyedFixedDoubleArray(LLoadKeyed* instr);
   void DoLoadKeyedFixedArray(LLoadKeyed* instr);
   void DoStoreKeyedExternalArray(LStoreKeyed* instr);
   void DoStoreKeyedFixedDoubleArray(LStoreKeyed* instr);
   void DoStoreKeyedFixedArray(LStoreKeyed* instr);
 
-  Zone* zone_;
-  LPlatformChunk* const chunk_;
-  MacroAssembler* const masm_;
-  CompilationInfo* const info_;
-
-  int current_block_;
-  int current_instruction_;
-  const ZoneList<LInstruction*>* instructions_;
   ZoneList<LEnvironment*> deoptimizations_;
   ZoneList<Deoptimizer::JumpTableEntry> deopt_jump_table_;
   ZoneList<Handle<Object> > deoptimization_literals_;
   int inlined_function_count_;
   Scope* const scope_;
-  Status status_;
   TranslationBuffer translations_;
   ZoneList<LDeferredCode*> deferred_;
   int osr_pc_offset_;
-  int last_lazy_deopt_pc_;
   bool frame_is_built_;
 
   // Builder that keeps track of safepoints in the code. The table
   // itself is emitted at the end of the generated code.
   SafepointTableBuilder safepoints_;
 
   // Compiler from a set of parallel moves to a sequential list of moves.
   LGapResolver resolver_;
 
   Safepoint::Kind expected_safepoint_kind_;
@@ skipping 74 matching lines @@
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
   int instruction_index_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_CODEGEN_ARM_H_