src/share/vm/asm/assembler.hpp

rev 12485 : 8173465: Introduce NearLabel for branches known to be short.

*** 91,100 ****
--- 91,104 ----
    int _patches[PatchCacheSize];
    int _patch_index;
    GrowableArray<int>* _patch_overflow;
  
    Label(const Label&) { ShouldNotReachHere(); }
+  protected:
+ 
+   // The label will be bound to a location near its users.
+   unsigned int _is_near:1;
  
   public:
  
    /**
     * After binding, be sure 'patch_instructions' is called later to link
*** 124,133 ****
--- 128,141 ----
  
    bool is_bound() const    { return _loc >=  0; }
    bool is_unbound() const  { return _loc == -1 && _patch_index > 0; }
    bool is_unused() const   { return _loc == -1 && _patch_index == 0; }
  
+   // The label will be bound to a location near its users. Users can
+   // optimize on this information, e.g. generate short branches.
+   bool is_near()           { return _is_near; }
+ 
    /**
     * Adds a reference to an unresolved displacement instruction to
     * this unbound label
     *
     * @param cb         the code buffer being patched
*** 143,159 ****
--- 151,175 ----
  
    void init() {
      _loc = -1;
      _patch_index = 0;
      _patch_overflow = NULL;
+     _is_near = false;
    }
  
    Label() {
      init();
    }
  };
  
+ // A NearLabel must be bound to a location near its users. Users can
+ // optimize on this information, e.g. generate short branches.
+ class NearLabel : public Label {
+  public:
+   NearLabel() : Label() { _is_near = true; }
+ };
+ 
  // A union type for code which has to assemble both constant and
  // non-constant operands, when the distinction cannot be made
  // statically.
  class RegisterOrConstant VALUE_OBJ_CLASS_SPEC {
   private: