Fast allocation of block contexts.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 9480fc4b1da26c84edf0deda689d272950e95e7b..62d480afff354c75de295934e1286c7fa432679f 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -62,6 +62,7 @@ namespace internal {
   V(StackCheck)                          \
   V(FastNewClosure)                      \
   V(FastNewContext)                      \
+  V(FastNewBlockContext)                 \
   V(FastCloneShallowArray)               \
   V(RevertToNumber)                      \
   V(ToBoolean)                           \
@@ -349,6 +350,24 @@ class FastNewContextStub : public CodeStub {
 };
 
 
+class FastNewBlockContextStub : public CodeStub {
+ public:
+  static const int kMaximumSlots = 64;
+
+  explicit FastNewBlockContextStub(int slots) : slots_(slots) {
+    ASSERT(slots_ > 0 && slots <= kMaximumSlots);

[danno, 2011/10/05 12:30:09]

nit: use either both slots_ or slots

[Steven, 2011/10/05 15:40:03]

Done.

+  }
+
+  void Generate(MacroAssembler* masm);
+
+ private:
+  int slots_;
+
+  Major MajorKey() { return FastNewBlockContext; }
+  int MinorKey() { return slots_; }
+};
+
+
 class FastCloneShallowArrayStub : public CodeStub {
  public:
   // Maximum length of copied elements array.