1 files changed, 55 insertions, 4 deletions

diff --git a/deps/v8/src/assembler.h b/deps/v8/src/assembler.h
index 157743359..d28bf4370 100644
--- a/deps/v8/src/assembler.h
+++ b/deps/v8/src/assembler.h
@@ -57,7 +57,7 @@ class Label BASE_EMBEDDED {
 
   INLINE(void Unuse())            { pos_ = 0; }
 
-  INLINE(bool is_bound()  const)  { return pos_ <  0; }
+  INLINE(bool is_bound() const)  { return pos_ <  0; }
   INLINE(bool is_unused() const)  { return pos_ == 0; }
   INLINE(bool is_linked() const)  { return pos_ >  0; }
 
@@ -92,6 +92,57 @@ class Label BASE_EMBEDDED {
 
 
 // -----------------------------------------------------------------------------
+// NearLabels are labels used for short jumps (in Intel jargon).
+// NearLabels should be used if it can be guaranteed that the jump range is
+// within -128 to +127. We already use short jumps when jumping backwards,
+// so using a NearLabel will only have performance impact if used for forward
+// jumps.
+class NearLabel BASE_EMBEDDED {
+ public:
+  NearLabel() { Unuse(); }
+  ~NearLabel() { ASSERT(!is_linked()); }
+
+  void Unuse() {
+    pos_ = -1;
+    unresolved_branches_ = 0;
+#ifdef DEBUG
+    for (int i = 0; i < kMaxUnresolvedBranches; i++) {
+      unresolved_positions_[i] = -1;
+    }
+#endif
+  }
+
+  int pos() {
+    ASSERT(is_bound());
+    return pos_;
+  }
+
+  bool is_bound() { return pos_ >= 0; }
+  bool is_linked() { return !is_bound() && unresolved_branches_ > 0; }
+  bool is_unused() { return !is_bound() && unresolved_branches_ == 0; }
+
+  void bind_to(int position) {
+    ASSERT(!is_bound());
+    pos_ = position;
+  }
+
+  void link_to(int position) {
+    ASSERT(!is_bound());
+    ASSERT(unresolved_branches_ < kMaxUnresolvedBranches);
+    unresolved_positions_[unresolved_branches_++] = position;
+  }
+
+ private:
+  static const int kMaxUnresolvedBranches = 8;
+  int pos_;
+  int unresolved_branches_;
+  int unresolved_positions_[kMaxUnresolvedBranches];
+
+  friend class Assembler;
+};
+
+
+// -----------------------------------------------------------------------------
 // Relocation information
 
 
@@ -181,10 +232,10 @@ class RelocInfo BASE_EMBEDDED {
   static inline int ModeMask(Mode mode) { return 1 << mode; }
 
   // Accessors
-  byte* pc() const  { return pc_; }
+  byte* pc() const { return pc_; }
   void set_pc(byte* pc) { pc_ = pc; }
   Mode rmode() const {  return rmode_; }
-  intptr_t data() const  { return data_; }
+  intptr_t data() const { return data_; }
 
   // Apply a relocation by delta bytes
   INLINE(void apply(intptr_t delta));
@@ -339,7 +390,7 @@ class RelocIterator: public Malloced {
   explicit RelocIterator(const CodeDesc& desc, int mode_mask = -1);
 
   // Iteration
-  bool done() const  { return done_; }
+  bool done() const { return done_; }
   void next();
 
   // Return pointer valid until next next().