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

src/arm/lithium-codegen-arm.h

Index: src/arm/lithium-codegen-arm.h
===================================================================
--- src/arm/lithium-codegen-arm.h	(revision 7959)
+++ src/arm/lithium-codegen-arm.h	(working copy)
@@ -51,6 +51,7 @@
         current_instruction_(-1),
         instructions_(chunk->instructions()),
         deoptimizations_(4),
+        deopt_jump_table_(4),
         deoptimization_literals_(8),
         inlined_function_count_(0),
         scope_(info->scope()),
@@ -172,6 +173,7 @@
   bool GeneratePrologue();
   bool GenerateBody();
   bool GenerateDeferredCode();
+  bool GenerateDeoptJumpTable();
   bool GenerateSafepointTable();
 
   enum SafepointMode {
@@ -289,6 +291,14 @@
                                        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_;
@@ -297,6 +307,7 @@
   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_;