Optimise the deoptimisation check to improve performance on modern ARM cores....

src/arm/lithium-codegen-arm.h

 // Copyright 2011 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 33 matching lines @@
 class LCodeGen BASE_EMBEDDED {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)
       : chunk_(chunk),
         masm_(assembler),
         info_(info),
         current_block_(-1),
         current_instruction_(-1),
         instructions_(chunk->instructions()),
         deoptimizations_(4),
+        deopt_jump_table_(4),
         deoptimization_literals_(8),
         inlined_function_count_(0),
         scope_(info->scope()),
         status_(UNUSED),
         deferred_(8),
         osr_pc_offset_(-1),
         resolver_(this),
         expected_safepoint_kind_(Safepoint::kSimple) {
     PopulateDeoptimizationLiteralsWithInlinedFunctions();
   }
@@ skipping 101 matching lines @@
   void Abort(const char* format, ...);
   void Comment(const char* format, ...);
 
   void AddDeferredCode(LDeferredCode* code) { deferred_.Add(code); }
 
   // Code generation passes.  Returns true if code generation should
   // continue.
   bool GeneratePrologue();
   bool GenerateBody();
   bool GenerateDeferredCode();
+  bool GenerateDeoptJumpTable();
   bool GenerateSafepointTable();
 
   enum SafepointMode {
     RECORD_SIMPLE_SAFEPOINT,
     RECORD_SAFEPOINT_WITH_REGISTERS_AND_NO_ARGUMENTS
   };
 
   void CallCode(Handle<Code> code,
                 RelocInfo::Mode mode,
                 LInstruction* instr);
@@ skipping 97 matching lines @@
 
   // Emits optimized code for %_IsConstructCall().
   // Caller should branch on equal condition.
   void EmitIsConstructCall(Register temp1, Register temp2);
 
   void EmitLoadFieldOrConstantFunction(Register result,
                                        Register object,
                                        Handle<Map> type,
                                        Handle<String> name);
 
+  struct JumpTableEntry {
+    explicit inline JumpTableEntry(Address entry)
+        : label(),
+          address(entry) { }
+    Label label;
+    Address address;
+  };
+
   LChunk* const chunk_;
   MacroAssembler* const masm_;
   CompilationInfo* const info_;
 
   int current_block_;
   int current_instruction_;
   const ZoneList<LInstruction*>* instructions_;
   ZoneList<LEnvironment*> deoptimizations_;
+  ZoneList<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_;
 
   // Builder that keeps track of safepoints in the code. The table
   // itself is emitted at the end of the generated code.
@@ skipping 72 matching lines @@
  private:
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_CODEGEN_ARM_H_