[LCG] Add some basic methods for querying the parent/child relationships

of SCCs in the SCC DAG. Exercise them in the big graph test case. These
will be especially useful for establishing invariants in insertion
logic.

llvm-svn: 207749

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/include/llvm/Analysis/LazyCallGraph.h b/llvm/include/llvm/Analysis/LazyCallGraph.h
index e5dd5cc2caa..df4fddf8669 100644
--- a/llvm/include/llvm/Analysis/LazyCallGraph.h
+++ b/llvm/include/llvm/Analysis/LazyCallGraph.h
@@ -238,6 +238,20 @@ public:
       return iterator_range<parent_iterator>(parent_begin(), parent_end());
     }
 
+    /// \brief Test if this SCC is a parent of \a C.
+    bool isParentOf(const SCC &C) const { return C.isChildOf(*this); }
+
+    /// \brief Test if this SCC is an ancestor of \a C.
+    bool isAncestorOf(const SCC &C) const { return C.isDescendantOf(*this); }
+
+    /// \brief Test if this SCC is a child of \a C.
+    bool isChildOf(const SCC &C) const {
+      return ParentSCCs.count(const_cast<SCC *>(&C));
+    }
+
+    /// \brief Test if this SCC is a descendant of \a C.
+    bool isDescendantOf(const SCC &C) const;
+
     ///@{
     /// \name Mutation API
     ///