ScheduleTreeThreadSpecificMarker: introduce (static) copy constructor

Unlike other schedule tree node types, ScheduleTreeThreadSpecificMarker
did not have a custom copy constructor since it was added in
e1db3a9 (insert thread specific
markers, Thu Apr 19 15:07:33 2018 +0200).  Introduce a private copy
constructor to ScheduleTreeThreadSpecificMarker, along with the static
member function that returns a copy of the given
ScheduleTreeThreadSpecificMarker wrapped in a unique pointer to force
the caller only keep unique pointers to schedule node trees.

This commit completes the removal of public constructors from schedule
node types and removes the code that became unnecessary.

Author: ftynse

tc/core/polyhedral/schedule_tree.cc

@@ -124,11 +124,6 @@ vector<ScheduleTree*> ancestorsInSubTree(
 }
 
 static std::unique_ptr<ScheduleTree> makeElem(const ScheduleTree& st) {
-#define ELEM_MAKE_CASE(CLASS)                                                \
-  else if (st.type_ == CLASS::NodeType) {                                    \
-    return std::unique_ptr<CLASS>(new CLASS(static_cast<const CLASS&>(st))); \
-  }
-
 #define ELEM_MAKE_CASE_CSTR(CLASS)                      \
   else if (st.type_ == CLASS::NodeType) {               \
     return CLASS::make(static_cast<const CLASS*>(&st)); \
@@ -145,10 +140,9 @@ static std::unique_ptr<ScheduleTree> makeElem(const ScheduleTree& st) {
   ELEM_MAKE_CASE_CSTR(ScheduleTreeMapping)
   ELEM_MAKE_CASE_CSTR(ScheduleTreeSequence)
   ELEM_MAKE_CASE_CSTR(ScheduleTreeSet)
-  ELEM_MAKE_CASE(ScheduleTreeThreadSpecificMarker)
+  ELEM_MAKE_CASE_CSTR(ScheduleTreeThreadSpecificMarker)
 
 #undef ELEM_MAKE_CASE_CSTR
-#undef ELEM_MAKE_CASE
 
   LOG(FATAL) << "NYI: ScheduleTree from type: " << static_cast<int>(st.type_);
   return nullptr;

tc/core/polyhedral/schedule_tree_elem.cc

@@ -271,6 +271,16 @@ ScheduleTreeThreadSpecificMarker::make(
   return res;
 }
 
+std::unique_ptr<ScheduleTreeThreadSpecificMarker>
+ScheduleTreeThreadSpecificMarker::make(
+    const ScheduleTreeThreadSpecificMarker* tree,
+    std::vector<ScheduleTreeUPtr>&& children) {
+  auto res = std::unique_ptr<ScheduleTreeThreadSpecificMarker>(
+      new ScheduleTreeThreadSpecificMarker(*tree));
+  res->appendChildren(std::move(children));
+  return res;
+}
+
 bool ScheduleTreeBand::operator==(const ScheduleTreeBand& other) const {
   if (permutable_ != other.permutable_) {
     return false;

tc/core/polyhedral/schedule_tree_elem.h

@@ -332,6 +332,8 @@ struct ScheduleTreeThreadSpecificMarker : public ScheduleTree {
  private:
   explicit ScheduleTreeThreadSpecificMarker(isl::ctx ctx)
       : ScheduleTree(ctx, {}, NodeType) {}
+  ScheduleTreeThreadSpecificMarker(const ScheduleTreeThreadSpecificMarker& tree)
+      : ScheduleTree(tree) {}
 
  public:
   virtual ~ScheduleTreeThreadSpecificMarker() override {}
@@ -346,6 +348,9 @@ struct ScheduleTreeThreadSpecificMarker : public ScheduleTree {
   static std::unique_ptr<ScheduleTreeThreadSpecificMarker> make(
       isl::ctx ctx,
       std::vector<ScheduleTreeUPtr>&& children = {});
+  static std::unique_ptr<ScheduleTreeThreadSpecificMarker> make(
+      const ScheduleTreeThreadSpecificMarker* tree,
+      std::vector<ScheduleTreeUPtr>&& children = {});
 
   virtual std::ostream& write(std::ostream& os) const override;
 };