IR: Add Function metadata attachments

Add IR support for `Metadata` attachments.  Assembly and bitcode support
will follow shortly, but for now we just have unit tests.  This is part
of PR23340.

llvm-svn: 235783

3 files changed, 82 insertions, 0 deletions

diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 227dfef9e98..ced989ab11d 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -324,6 +324,9 @@ void Function::dropAllReferences() {
   // Prefix and prologue data are stored in a side table.
   setPrefixData(nullptr);
   setPrologueData(nullptr);
+
+  // Metadata is stored in a side-table.
+  clearMetadata();
 }
 
 void Function::addAttribute(unsigned i, Attribute::AttrKind attr) {
diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index a13afdd9b35..edffef31511 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -992,6 +992,9 @@ public:
   /// Collection of per-instruction metadata used in this context.
   DenseMap<const Instruction *, MDAttachmentMap> InstructionMetadata;
 
+  /// Collection of per-function metadata used in this context.
+  DenseMap<const Function *, MDAttachmentMap> FunctionMetadata;
+
   /// DiscriminatorTable - This table maps file:line locations to an
   /// integer representing the next DWARF path discriminator to assign to
   /// instructions in different blocks at the same location.
diff --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index eb1bd310511..23a17a52b2b 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -1160,3 +1160,79 @@ void Instruction::clearMetadataHashEntries() {
   getContext().pImpl->InstructionMetadata.erase(this);
   setHasMetadataHashEntry(false);
 }
+
+MDNode *Function::getMetadata(unsigned KindID) const {
+  if (!hasMetadata())
+    return nullptr;
+  return getContext().pImpl->FunctionMetadata[this].lookup(KindID);
+}
+
+MDNode *Function::getMetadata(StringRef Kind) const {
+  if (!hasMetadata())
+    return nullptr;
+  return getMetadata(getContext().getMDKindID(Kind));
+}
+
+void Function::setMetadata(unsigned KindID, MDNode *MD) {
+  if (MD) {
+    if (!hasMetadata())
+      setHasMetadataHashEntry(true);
+
+    getContext().pImpl->FunctionMetadata[this].set(KindID, *MD);
+    return;
+  }
+
+  // Nothing to unset.
+  if (!hasMetadata())
+    return;
+
+  auto &Store = getContext().pImpl->FunctionMetadata[this];
+  Store.erase(KindID);
+  if (Store.empty())
+    clearMetadata();
+}
+
+void Function::setMetadata(StringRef Kind, MDNode *MD) {
+  if (!MD && !hasMetadata())
+    return;
+  setMetadata(getContext().getMDKindID(Kind), MD);
+}
+
+void Function::getAllMetadata(
+    SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const {
+  MDs.clear();
+
+  if (!hasMetadata())
+    return;
+
+  getContext().pImpl->FunctionMetadata[this].getAll(MDs);
+}
+
+void Function::dropUnknownMetadata(ArrayRef<unsigned> KnownIDs) {
+  if (!hasMetadata())
+    return;
+  if (KnownIDs.empty()) {
+    clearMetadata();
+    return;
+  }
+
+  SmallSet<unsigned, 5> KnownSet;
+  KnownSet.insert(KnownIDs.begin(), KnownIDs.end());
+
+  auto &Store = getContext().pImpl->FunctionMetadata[this];
+  assert(!Store.empty());
+
+  Store.remove_if([&KnownSet](const std::pair<unsigned, TrackingMDNodeRef> &I) {
+    return !KnownSet.count(I.first);
+  });
+
+  if (Store.empty())
+    clearMetadata();
+}
+
+void Function::clearMetadata() {
+  if (!hasMetadata())
+    return;
+  getContext().pImpl->FunctionMetadata.erase(this);
+  setHasMetadataHashEntry(false);
+}