Tiny change flags cleanups.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
===================================================================
--- src/hydrogen-instructions.h	(revision 9087)
+++ src/hydrogen-instructions.h	(working copy)
@@ -513,19 +513,6 @@
 
   static const int kChangesToDependsFlagsLeftShift = 1;
 
-  static int ChangesFlagsMask() {
-    int result = 0;
-    // Create changes mask.
-#define DECLARE_DO(type) result |= (1 << kChanges##type);
-  GVN_FLAG_LIST(DECLARE_DO)
-#undef DECLARE_DO
-    return result;
-  }
-
-  static int DependsFlagsMask() {
-    return ConvertChangesToDependsFlags(ChangesFlagsMask());
-  }
-
   static int ConvertChangesToDependsFlags(int flags) {
     return flags << kChangesToDependsFlagsLeftShift;
   }
@@ -629,6 +616,8 @@
   void ClearAllSideEffects() { flags_ &= ~AllSideEffects(); }
   bool HasSideEffects() const { return (flags_ & AllSideEffects()) != 0; }
 
+  int ChangesFlags() const { return flags_ & ChangesFlagsMask(); }
+
   Range* range() const { return range_; }
   bool HasRange() const { return range_ != NULL; }
   void AddNewRange(Range* r);
@@ -693,6 +682,15 @@
   }
 
  private:
+  static int ChangesFlagsMask() {
+    int result = 0;
+    // Create changes mask.
+#define DECLARE_DO(type) result |= (1 << kChanges##type);

[Kevin Millikin (Chromium), 2011/09/01 10:03:27]

This wasn't introduced in your change, but could you should rename this macro
(though I find the name funny whenever I see it).

I once defined a macro called "DECLARE_DO", because it was declaring a bunch of
functions named DoXXX.

Then, somebody else copied it everywhere they could, and now we have DECLARE_DO
for things that are declaring something other than "Do" or that are not even
declaring anything at all.  :)

#define ADD_FLAG(flag) result |= (1 << kChanges##flag);
  GVN_FLAG_LIST(ADD_FLAG)
#undef ADD_FLAG

[Sven Panne, 2011/09/01 11:05:37]

Done. Your story explains the strange name, I was always curious about the
intention behind it. :-) Perhaps one should rename the FOO_LIST macros into
FOR_EACH_FOO, this would improve the readability of our high-tech 2nd-order
macros a bit IMHO...

+  GVN_FLAG_LIST(DECLARE_DO)
+#undef DECLARE_DO
+    return result;
+  }
+
   // A flag mask to mark an instruction as having arbitrary side effects.
   static int AllSideEffects() {
     return ChangesFlagsMask() & ~(1 << kChangesOsrEntries);