ScheduleTreeElemSequence: require isl::ctx in the constructor

Since ScheduleTreeElemSequence is now a subclass of ScheduleTree, it
needs an isl::ctx to construct the ScheduleTree.  It is available in all
callsites of the ScheduleTreeElemSequence constructor.  Pass it as an
argument.

Author: ftynse

tc/core/polyhedral/schedule_isl_conversion.cc

@@ -249,6 +249,7 @@ std::unique_ptr<ScheduleTreeElemBand> fromIslScheduleNodeBand(
 }
 
 std::unique_ptr<ScheduleTree> elemFromIslScheduleNode(isl::schedule_node node) {
+  auto ctx = node.get_ctx();
   if (auto band = node.as<isl::schedule_node_band>()) {
     return fromIslScheduleNodeBand(band);
   } else if (auto context = node.as<isl::schedule_node_context>()) {
@@ -281,7 +282,7 @@ std::unique_ptr<ScheduleTree> elemFromIslScheduleNode(isl::schedule_node node) {
     return nullptr;
   } else if (node.isa<isl::schedule_node_sequence>()) {
     return std::unique_ptr<ScheduleTreeElemSequence>(
-        new ScheduleTreeElemSequence());
+        new ScheduleTreeElemSequence(ctx));
   } else if (node.isa<isl::schedule_node_set>()) {
     return std::unique_ptr<ScheduleTreeElemSet>(new ScheduleTreeElemSet());
   }

tc/core/polyhedral/schedule_tree.h

@@ -420,9 +420,8 @@ struct ScheduleTree {
             ScheduleTreeUPtr>::value,
         "Arguments must be rvalue references to ScheduleTreeUPtr");
 
-    auto ctx = arg->ctx_; // FIXME: pass this to the constructor of T
-                          // when possible
-    auto res = ScheduleTreeUPtr(new T);
+    auto ctx = arg->ctx_;
+    auto res = ScheduleTreeUPtr(new T(ctx));
     res->appendChildren(
         vectorFromArgs(std::forward<Arg>(arg), std::forward<Args>(args)...));
 

tc/core/polyhedral/schedule_tree_elem.h

@@ -159,9 +159,8 @@ struct ScheduleTreeElemMapping : public ScheduleTree {
 struct ScheduleTreeElemSequence : public ScheduleTree {
   static constexpr detail::ScheduleTreeType NodeType =
       detail::ScheduleTreeType::Sequence;
-  explicit ScheduleTreeElemSequence()
-      : ScheduleTree(isl::with_exceptions::globalIslCtx(), {}, NodeType) {
-  } // FIXME: accept a ctx instead of using the global ctx
+  explicit ScheduleTreeElemSequence(isl::ctx ctx)
+      : ScheduleTree(ctx, {}, NodeType) {}
   ScheduleTreeElemSequence(const ScheduleTreeElemSequence& eb)
       : ScheduleTree(eb) {}
   virtual ~ScheduleTreeElemSequence() override {}