IR: Split out DebugInfoMetadata.h, NFC

Move debug-info-centred `Metadata` subclasses into their own
header/source file.  A couple of private template functions are needed
from both `Metadata.cpp` and `DebugInfoMetadata.cpp`, so I've moved them
to `lib/IR/MetadataImpl.h`.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227835 91177308-0d34-0410-b5e6-96231b3b80d8

lib/IR/DebugInfoMetadata.cpp

@@ -0,0 +1,101 @@
+//===- DebugInfoMetadata.cpp - Implement debug info metadata --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the debug info Metadata classes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/DebugInfoMetadata.h"
+#include "LLVMContextImpl.h"
+#include "MetadataImpl.h"
+
+using namespace llvm;
+
+MDLocation::MDLocation(LLVMContext &C, StorageType Storage, unsigned Line,
+                       unsigned Column, ArrayRef<Metadata *> MDs)
+    : MDNode(C, MDLocationKind, Storage, MDs) {
+  assert((MDs.size() == 1 || MDs.size() == 2) &&
+         "Expected a scope and optional inlined-at");
+
+  // Set line and column.
+  assert(Line < (1u << 24) && "Expected 24-bit line");
+  assert(Column < (1u << 16) && "Expected 16-bit column");
+
+  SubclassData32 = Line;
+  SubclassData16 = Column;
+}
+
+static void adjustLine(unsigned &Line) {
+  // Set to unknown on overflow.  Still use 24 bits for now.
+  if (Line >= (1u << 24))
+    Line = 0;
+}
+
+static void adjustColumn(unsigned &Column) {
+  // Set to unknown on overflow.  We only have 16 bits to play with here.
+  if (Column >= (1u << 16))
+    Column = 0;
+}
+
+MDLocation *MDLocation::getImpl(LLVMContext &Context, unsigned Line,
+                                unsigned Column, Metadata *Scope,
+                                Metadata *InlinedAt, StorageType Storage,
+                                bool ShouldCreate) {
+  // Fixup line/column.
+  adjustLine(Line);
+  adjustColumn(Column);
+
+  if (Storage == Uniqued) {
+    if (auto *N =
+            getUniqued(Context.pImpl->MDLocations,
+                       MDLocationInfo::KeyTy(Line, Column, Scope, InlinedAt)))
+      return N;
+    if (!ShouldCreate)
+      return nullptr;
+  } else {
+    assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
+  }
+
+  SmallVector<Metadata *, 2> Ops;
+  Ops.push_back(Scope);
+  if (InlinedAt)
+    Ops.push_back(InlinedAt);
+  return storeImpl(new (Ops.size())
+                       MDLocation(Context, Storage, Line, Column, Ops),
+                   Storage, Context.pImpl->MDLocations);
+}
+
+GenericDebugNode *GenericDebugNode::getImpl(LLVMContext &Context, unsigned Tag,
+                                            StringRef Header,
+                                            ArrayRef<Metadata *> DwarfOps,
+                                            StorageType Storage,
+                                            bool ShouldCreate) {
+  unsigned Hash = 0;
+  if (Storage == Uniqued) {
+    GenericDebugNodeInfo::KeyTy Key(Tag, Header, DwarfOps);
+    if (auto *N = getUniqued(Context.pImpl->GenericDebugNodes, Key))
+      return N;
+    if (!ShouldCreate)
+      return nullptr;
+    Hash = Key.getHash();
+  } else {
+    assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
+  }
+
+  // Use a nullptr for empty headers.
+  Metadata *PreOps[] = {Header.empty() ? nullptr
+                                       : MDString::get(Context, Header)};
+  return storeImpl(new (DwarfOps.size() + 1) GenericDebugNode(
+                       Context, Storage, Hash, Tag, PreOps, DwarfOps),
+                   Storage, Context.pImpl->GenericDebugNodes);
+}
+
+void GenericDebugNode::recalculateHash() {
+  setHash(GenericDebugNodeInfo::KeyTy::calculateHash(this));
+}