IR: MDNode => Value: Add Instruction::getMDNode()

Add `Instruction::getMDNode()` that casts to `MDNode` before changing
`Instruction::getMetadata()` to return `Value`.  This avoids adding
`cast_or_null<MDNode>` boiler-plate throughout the code.

Part of PR21433.

llvm-svn: 221023

2 files changed, 28 insertions, 0 deletions

diff --git a/llvm/include/llvm/IR/Instruction.h b/llvm/include/llvm/IR/Instruction.h
index 4baacba78ed..ac042ff7ba9 100644
--- a/llvm/include/llvm/IR/Instruction.h
+++ b/llvm/include/llvm/IR/Instruction.h
@@ -153,6 +153,24 @@ public:
     return getMetadataImpl(Kind);
   }
 
+  /// Get the the metadata as an MDNode.
+  ///
+  /// \pre Any KindID metadata is implemented using \a MDNode.
+  MDNode *getMDNode(unsigned KindID) const {
+    if (!hasMetadata())
+      return nullptr;
+    return getMDNodeImpl(KindID);
+  }
+
+  /// Get the the metadata as an MDNode.
+  ///
+  /// \pre Any KindID metadata is implemented using \a MDNode.
+  MDNode *getMDNode(StringRef Kind) const {
+    if (!hasMetadata())
+      return nullptr;
+    return getMDNodeImpl(Kind);
+  }
+
   /// getAllMetadata - Get all metadata attached to this Instruction.  The first
   /// element of each pair returned is the KindID, the second element is the
   /// metadata value.  This list is returned sorted by the KindID.
@@ -273,6 +291,8 @@ private:
   // These are all implemented in Metadata.cpp.
   MDNode *getMetadataImpl(unsigned KindID) const;
   MDNode *getMetadataImpl(StringRef Kind) const;
+  MDNode *getMDNodeImpl(unsigned KindID) const;
+  MDNode *getMDNodeImpl(StringRef Kind) const;
   void getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned,MDNode*> > &)const;
   void getAllMetadataOtherThanDebugLocImpl(SmallVectorImpl<std::pair<unsigned,
                                            MDNode*> > &) const;
diff --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index 3d869e87c4d..60cd2fc9061 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -609,6 +609,14 @@ MDNode *Instruction::getMetadataImpl(StringRef Kind) const {
   return getMetadataImpl(getContext().getMDKindID(Kind));
 }
 
+MDNode *Instruction::getMDNodeImpl(unsigned KindID) const {
+  return getMetadataImpl(KindID);
+}
+
+MDNode *Instruction::getMDNodeImpl(StringRef Kind) const {
+  return getMetadataImpl(Kind);
+}
+
 void Instruction::dropUnknownMetadata(ArrayRef<unsigned> KnownIDs) {
   SmallSet<unsigned, 5> KnownSet;
   KnownSet.insert(KnownIDs.begin(), KnownIDs.end());