[ptr-traits] Merge the MetadataTracking helpers into the Metadata

[oota-llvm.git] / include / llvm / IR / Metadata.h

diff --git a/include/llvm/IR/Metadata.h b/include/llvm/IR/Metadata.h
index 2e9dc457bb00e0777428b5cf182a67f50f7989c5..2ea591383f82543d22fe42233e8593f044857770 100644 (file)
--- a/include/llvm/IR/Metadata.h
+++ b/include/llvm/IR/Metadata.h
@@ -18,10 +18,11 @@
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/ilist_node.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/IR/Constant.h"
-#include "llvm/IR/MetadataTracking.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Value.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <type_traits>
@@ -196,6 +197,77 @@ private:
   void untrack();
 };
 
+/// \brief API for tracking metadata references through RAUW and deletion.
+///
+/// Shared API for updating \a Metadata pointers in subclasses that support
+/// RAUW.
+///
+/// This API is not meant to be used directly.  See \a TrackingMDRef for a
+/// user-friendly tracking reference.
+class MetadataTracking {
+public:
+  /// \brief Track the reference to metadata.
+  ///
+  /// Register \c MD with \c *MD, if the subclass supports tracking.  If \c *MD
+  /// gets RAUW'ed, \c MD will be updated to the new address.  If \c *MD gets
+  /// deleted, \c MD will be set to \c nullptr.
+  ///
+  /// If tracking isn't supported, \c *MD will not change.
+  ///
+  /// \return true iff tracking is supported by \c MD.
+  static bool track(Metadata *&MD) {
+    return track(&MD, *MD, static_cast<Metadata *>(nullptr));
+  }
+
+  /// \brief Track the reference to metadata for \a Metadata.
+  ///
+  /// As \a track(Metadata*&), but with support for calling back to \c Owner to
+  /// tell it that its operand changed.  This could trigger \c Owner being
+  /// re-uniqued.
+  static bool track(void *Ref, Metadata &MD, Metadata &Owner) {
+    return track(Ref, MD, &Owner);
+  }
+
+  /// \brief Track the reference to metadata for \a MetadataAsValue.
+  ///
+  /// As \a track(Metadata*&), but with support for calling back to \c Owner to
+  /// tell it that its operand changed.  This could trigger \c Owner being
+  /// re-uniqued.
+  static bool track(void *Ref, Metadata &MD, MetadataAsValue &Owner) {
+    return track(Ref, MD, &Owner);
+  }
+
+  /// \brief Stop tracking a reference to metadata.
+  ///
+  /// Stops \c *MD from tracking \c MD.
+  static void untrack(Metadata *&MD) { untrack(&MD, *MD); }
+  static void untrack(void *Ref, Metadata &MD);
+
+  /// \brief Move tracking from one reference to another.
+  ///
+  /// Semantically equivalent to \c untrack(MD) followed by \c track(New),
+  /// except that ownership callbacks are maintained.
+  ///
+  /// Note: it is an error if \c *MD does not equal \c New.
+  ///
+  /// \return true iff tracking is supported by \c MD.
+  static bool retrack(Metadata *&MD, Metadata *&New) {
+    return retrack(&MD, *MD, &New);
+  }
+  static bool retrack(void *Ref, Metadata &MD, void *New);
+
+  /// \brief Check whether metadata is replaceable.
+  static bool isReplaceable(const Metadata &MD);
+
+  typedef PointerUnion<MetadataAsValue *, Metadata *> OwnerTy;
+
+private:
+  /// \brief Track a reference to metadata for an owner.
+  ///
+  /// Generalized version of tracking.
+  static bool track(void *Ref, Metadata &MD, OwnerTy Owner);
+};
+
 /// \brief Shared implementation of use-lists for replaceable metadata.
 ///
 /// Most metadata cannot be RAUW'ed.  This is a shared implementation of