move extractDomainToThread into MappedScop, and rename to threadMappingSchedule

This function will be used in the following commits outside of
mapped_scop.cc and must become a part of the visible API.  Additionally,
as a member of MappedScop, it can obtain the number of mapped threads
directly.

Author: ftynse

tc/core/polyhedral/cuda/mapped_scop.cc

@@ -466,24 +466,6 @@ constexpr auto kBlock = "block";
 // Name of the space of warps
 constexpr auto kWarp = "warp";
 
-/*
- * Extract a mapping from the domain elements active at "tree"
- * to the thread identifiers, where all branches in "tree"
- * are assumed to have been mapped to thread identifiers.
- * "nThread" is the number of thread identifiers.
- * The result lives in a space of the form block[x, ...].
- */
-isl::multi_union_pw_aff extractDomainToThread(
-    const detail::ScheduleTree* tree,
-    size_t nThread) {
-  std::vector<mapping::MappingId> ids;
-  for (size_t i = 0; i < nThread; ++i) {
-    ids.emplace_back(mapping::ThreadId::makeId(i));
-  }
-  auto tupleId = isl::id(tree->ctx_, kBlock);
-  return extractDomainToIds(tree, ids, tupleId);
-}
-
 /*
  * Construct a mapping
  *
@@ -518,6 +500,16 @@ isl::multi_aff constructThreadToWarp(
 }
 } // namespace
 
+isl::multi_union_pw_aff MappedScop::threadMappingSchedule(
+    const detail::ScheduleTree* tree) const {
+  std::vector<mapping::MappingId> ids;
+  for (size_t i = 0; i < numThreads.view.size(); ++i) {
+    ids.emplace_back(mapping::ThreadId::makeId(i));
+  }
+  auto tupleId = isl::id(tree->ctx_, kBlock);
+  return extractDomainToIds(tree, ids, tupleId);
+}
+
 Scop::SyncLevel MappedScop::findBestSync(
     detail::ScheduleTree* st1,
     detail::ScheduleTree* st2,
@@ -708,7 +700,7 @@ void MappedScop::insertBestSyncInSeq(detail::ScheduleTree* seq) {
 
   auto outer = hasOuterSequentialMember(scop_->scheduleRoot(), seq);
 
-  auto domainToThread = extractDomainToThread(seq, numThreads.view.size());
+  auto domainToThread = threadMappingSchedule(seq);
   auto threadToWarp = constructThreadToWarp(seq->ctx_, 32, numThreads);
   auto domainToWarp = domainToThread.apply(threadToWarp);
 

tc/core/polyhedral/cuda/mapped_scop.h

@@ -186,6 +186,13 @@ class MappedScop {
       size_t nChildren,
       bool hasOuterSequentialMember);
 
+  // Extract a mapping from the domain elements active at "tree"
+  // to the thread identifiers, where all branches in "tree"
+  // are assumed to have been mapped to thread identifiers.
+  // The result lives in a space of the form block[x, ...].
+  isl::multi_union_pw_aff threadMappingSchedule(
+      const detail::ScheduleTree* tree) const;
+
  private:
   // Insert the optimal combination of synchronizations in the sequence
   void insertBestSyncInSeq(detail::ScheduleTree* seq);