Check the depth of the constructed HEnvironment.

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index 8b507c26b3fdff31a006418196bdd255c0997036..5f0163c266ef195c37825ec9fbee4f0bf06093d7 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -448,6 +448,23 @@ class HEnvironment: public ZoneObject {
  private:
   explicit HEnvironment(const HEnvironment* other);
 
+  void CheckDepth() {
+    // Verify that we are not trying to create an
+    // impossibly deeply nested environment.
+    if (!FLAG_limit_inlining) return;
+
+    static const int kMaxDepth = 4;
+
+    int cnt = 0;
+    for (HEnvironment* env = this;
+         env != NULL && cnt <= kMaxDepth;  // Check cnt to avoid infinite loop.
+         env = env->outer()) {
+      cnt++;
+    }
+
+    CHECK(cnt <= kMaxDepth);
+  }
+
   // True if index is included in the expression stack part of the environment.
   bool HasExpressionAt(int index) const;