[compiler] Generalize JSContextSpecialization.

src/compiler/opcodes.h

Index: src/compiler/opcodes.h
diff --git a/src/compiler/opcodes.h b/src/compiler/opcodes.h
index 05851289b0318e4004cfd0eef290e156a12aa0d2..d4a514ae39bfe07eee00ba5bfccf935783a6159a 100644
--- a/src/compiler/opcodes.h
+++ b/src/compiler/opcodes.h
@@ -795,6 +795,10 @@ class V8_EXPORT_PRIVATE IrOpcode {
            (kNumberEqual <= value && value <= kStringLessThanOrEqual) ||
            (kWord32Equal <= value && value <= kFloat64LessThanOrEqual);
   }
+
+  static bool IsContextExtendingOpcode(Value value) {

[Michael Starzinger, 2017/01/13 13:36:26]

nit: Can we either rename this predicate to "IsContextChainExtendingOpcode" or
at least add a comment that explains this is about extending the context
_chain_. Otherwise this risks being confused with the context extension we
perform for e.h. with-contexts. A comment might be useful either way.

[neis, 2017/01/13 14:08:02]

Done. Totally agree.

+    return kJSCreateFunctionContext <= value && value <= kJSCreateScriptContext;
+  }
 };
 
 V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream&, IrOpcode::Value);