Implement a simple hash function for libclang cursors

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@119876 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang-c/Index.h b/include/clang-c/Index.h
index ebe74e2..d7a4b60 100644
--- a/include/clang-c/Index.h
+++ b/include/clang-c/Index.h
@@ -1351,6 +1351,11 @@
 CINDEX_LINKAGE unsigned clang_equalCursors(CXCursor, CXCursor);
 
 /**
+ * \brief Compute a hash value for the given cursor.
+ */
+CINDEX_LINKAGE unsigned clang_hashCursor(CXCursor);
+  
+/**
  * \brief Retrieve the kind of the given cursor.
  */
 CINDEX_LINKAGE enum CXCursorKind clang_getCursorKind(CXCursor);
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 9116667..2eb2096 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -3137,6 +3137,15 @@
   return X == Y;
 }
 
+unsigned clang_hashCursor(CXCursor C) {
+  unsigned Index = 0;
+  if (clang_isExpression(C.kind) || clang_isStatement(C.kind))
+    Index = 1;
+  
+  return llvm::DenseMapInfo<std::pair<unsigned, void*> >::getHashValue(
+                                        std::make_pair(C.kind, C.data[Index]));
+}
+
 unsigned clang_isInvalid(enum CXCursorKind K) {
   return K >= CXCursor_FirstInvalid && K <= CXCursor_LastInvalid;
 }
diff --git a/tools/libclang/libclang.darwin.exports b/tools/libclang/libclang.darwin.exports
index e132f7f..936ad46 100644
--- a/tools/libclang/libclang.darwin.exports
+++ b/tools/libclang/libclang.darwin.exports
@@ -102,6 +102,7 @@
 _clang_getTranslationUnitSpelling
 _clang_getTypeDeclaration
 _clang_getTypeKindSpelling
+_clang_hashCursor
 _clang_isCursorDefinition
 _clang_isDeclaration
 _clang_isExpression
diff --git a/tools/libclang/libclang.exports b/tools/libclang/libclang.exports
index fce89ca..de770ee 100644
--- a/tools/libclang/libclang.exports
+++ b/tools/libclang/libclang.exports
@@ -102,6 +102,7 @@
 clang_getTranslationUnitSpelling
 clang_getTypeDeclaration
 clang_getTypeKindSpelling
+clang_hashCursor
 clang_isCursorDefinition
 clang_isDeclaration
 clang_isExpression