DebugInfo: Gut DIDescriptor

PR23080 is almost finished.  With this commit, there's no consequential
API in `DIDescriptor` and its subclasses.  What's left?

  - Default-constructed to `nullptr`.
  - Handy `const_cast<>` (constructed from `const`, but accessors are
    non-`const`).

I think the safe way to catch those is to delete the classes and fix
compile errors.  That'll be my next step, after I delete the `DITypeRef`
(etc.) wrapper around `MDTypeRef`.

llvm-svn: 235069

3 files changed, 8 insertions, 22 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 46f3eb3201d..91546529877 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1405,9 +1405,10 @@ void DwarfUnit::constructArrayTypeDIE(DIE &Buffer, DICompositeType CTy) {
   // Add subranges to array type.
   DIArray Elements = CTy->getElements();
   for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
-    DIDescriptor Element = Elements[i];
-    if (Element.getTag() == dwarf::DW_TAG_subrange_type)
-      constructSubrangeDIE(Buffer, cast<MDSubrange>(Element), IdxTy);
+    // FIXME: Should this really be such a loose cast?
+    if (auto *Element = dyn_cast_or_null<DebugNode>(Elements[i]))
+      if (Element->getTag() == dwarf::DW_TAG_subrange_type)
+        constructSubrangeDIE(Buffer, cast<MDSubrange>(Element), IdxTy);
   }
 }
 
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index 893f9f29548..67aa09a14a1 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -203,7 +203,7 @@ DIImportedEntity DIBuilder::createImportedDeclaration(DIScope Context,
   // types that have one.
   return ::createImportedModule(
       VMContext, dwarf::DW_TAG_imported_declaration, Context,
-      DebugNodeRef::get(cast_or_null<DebugNode>(Decl.get())), Line, Name,
+      DebugNodeRef::get(cast_or_null<DebugNode>(Decl)), Line, Name,
       AllImportedModules);
 }
 
@@ -318,7 +318,7 @@ DIDerivedType DIBuilder::createStaticMemberType(DIDescriptor Scope,
                                                 unsigned Flags,
                                                 llvm::Constant *Val) {
   // TAG_member is encoded in DIDerivedType format.
-  Flags |= DIDescriptor::FlagStaticMember;
+  Flags |= DebugNode::FlagStaticMember;
   return MDDerivedType::get(
       VMContext, dwarf::DW_TAG_member, Name, File, LineNumber,
       MDScopeRef::get(DIScope(getNonCompileUnitScope(Scope))),
@@ -529,8 +529,8 @@ DIBuilder::createForwardDecl(unsigned Tag, StringRef Name, DIDescriptor Scope,
   DICompositeType RetTy = MDCompositeType::get(
       VMContext, Tag, Name, F, Line,
       MDScopeRef::get(DIScope(getNonCompileUnitScope(Scope))), nullptr,
-      SizeInBits, AlignInBits, 0, DIDescriptor::FlagFwdDecl, nullptr,
-      RuntimeLang, nullptr, nullptr, UniqueIdentifier);
+      SizeInBits, AlignInBits, 0, DebugNode::FlagFwdDecl, nullptr, RuntimeLang,
+      nullptr, nullptr, UniqueIdentifier);
   if (!UniqueIdentifier.empty())
     retainType(RetTy);
   trackIfUnresolved(RetTy);
diff --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index d3388cbabef..d877325b1f1 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -307,21 +307,6 @@ bool DebugInfoFinder::addScope(DIScope Scope) {
   return true;
 }
 
-//===----------------------------------------------------------------------===//
-// DIDescriptor: dump routines for all descriptors.
-//===----------------------------------------------------------------------===//
-
-void DIDescriptor::dump() const {
-  print(dbgs());
-  dbgs() << '\n';
-}
-
-void DIDescriptor::print(raw_ostream &OS) const {
-  if (!get())
-    return;
-  get()->print(OS);
-}
-
 template <>
 DIDescriptor
 DIRef<DIDescriptor>::resolve(const DITypeIdentifierMap &Map) const {