CGDebugInfo: Factor out a getOrCreateStandaloneType() method.

Usually debug info is created on the fly while during codegen.
With this API it becomes possible to create standalone debug info
for types that are not referenced by any code, such as emitting debug info
for a clang module or for implementing something like -gfull.
Because on-the-fly debug info generation may still insert retained types
on top of them, all RetainedTypes are uniqued in CGDebugInfo::finalize().

llvm-svn: 246210

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -1398,8 +1398,15 @@ llvm::DIType *CGDebugInfo::getOrCreateRecordType(QualType RTy,
 
 llvm::DIType *CGDebugInfo::getOrCreateInterfaceType(QualType D,
                                                     SourceLocation Loc) {
+  return getOrCreateStandaloneType(D, Loc);
+}
+
+llvm::DIType *CGDebugInfo::getOrCreateStandaloneType(QualType D,
+                                                     SourceLocation Loc) {
   assert(DebugKind >= CodeGenOptions::LimitedDebugInfo);
+  assert(!D.isNull() && "null type");
   llvm::DIType *T = getOrCreateType(D, getOrCreateFile(Loc));
+  assert(T && "could not create debug info for type");
   RetainedTypes.push_back(D.getAsOpaquePtr());
   return T;
 }
@@ -3360,9 +3367,14 @@ void CGDebugInfo::finalize() {
 
   // We keep our own list of retained types, because we need to look
   // up the final type in the type cache.
-  for (std::vector<void *>::const_iterator RI = RetainedTypes.begin(),
-         RE = RetainedTypes.end(); RI != RE; ++RI)
-    DBuilder.retainType(cast<llvm::DIType>(TypeCache[*RI]));
+  llvm::DenseSet<void *> UniqueTypes;
+  UniqueTypes.resize(RetainedTypes.size() * 2);
+  for (auto &RT : RetainedTypes) {
+    if (!UniqueTypes.insert(RT).second)
+      continue;
+    if (auto MD = TypeCache[RT])
+      DBuilder.retainType(cast<llvm::DIType>(MD));
+  }
 
   DBuilder.finalize();
 }