Initial checkin of ValueHolder helper

llvm-svn: 8072

1 files changed, 16 insertions, 0 deletions

diff --git a/llvm/lib/Support/ValueHolder.cpp b/llvm/lib/Support/ValueHolder.cpp
new file mode 100644
index 00000000000..e0806b538a3
--- /dev/null
+++ b/llvm/lib/Support/ValueHolder.cpp
@@ -0,0 +1,16 @@
+//===-- ValueHolder.cpp - Wrapper for Value implementation ----------------===//
+//
+// This class defines a simple subclass of User, which keeps a pointer to a
+// Value, which automatically updates when Value::replaceAllUsesWith is called.
+// This is useful when you have pointers to Value's in your pass, but the
+// pointers get invalidated when some other portion of the algorithm is
+// replacing Values with other Values.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ValueHolder.h"
+#include "llvm/Type.h"
+
+ValueHolder::ValueHolder(Value *V) : User(Type::TypeTy, Value::TypeVal) {
+  Operands.push_back(Use(V, this));
+}