[CodeLayout] Refactor std::vector uses, namespace, and EdgeCountT. NFC

* Place types and functions in the llvm::codelayout namespace
* Change EdgeCountT from pair<pair<uint64_t, uint64_t>, uint64_t> to a struct and utilize structured bindings.
  It is not conventional to use the "T" suffix for structure types.
* Remove a redundant copy in ChainT::merge.
* Change {ExtTSPImpl,CDSortImpl}::run to use return value instead of an output parameter
* Rename applyCDSLayout to computeCacheDirectedLayout: (a) avoid rare
  abbreviation "CDS" (cache-directed sort) (b) "compute" is more conventional
  for the specific use case
* Change the parameter types from std::vector to ArrayRef so that
  SmallVector arguments can be used.
* Similarly, rename applyExtTspLayout to computeExtTspLayout.

Reviewed By: Amir

Differential Revision: https://reviews.llvm.org/D159526

1 files changed, 5 insertions, 5 deletions

diff --git a/bolt/lib/Passes/ReorderAlgorithm.cpp b/bolt/lib/Passes/ReorderAlgorithm.cpp
index b5052cd..3c3365e 100644
--- a/bolt/lib/Passes/ReorderAlgorithm.cpp
+++ b/bolt/lib/Passes/ReorderAlgorithm.cpp
@@ -531,21 +531,21 @@ void ExtTSPReorderAlgorithm::reorderBasicBlocks(BinaryFunction &BF,
   }
 
   // Initialize CFG edges
-  using JumpT = std::pair<uint64_t, uint64_t>;
-  std::vector<std::pair<JumpT, uint64_t>> JumpCounts;
+  std::vector<codelayout::EdgeCount> JumpCounts;
   for (BinaryBasicBlock *BB : BF.getLayout().blocks()) {
     auto BI = BB->branch_info_begin();
     for (BinaryBasicBlock *SuccBB : BB->successors()) {
       assert(BI->Count != BinaryBasicBlock::COUNT_NO_PROFILE &&
              "missing profile for a jump");
-      auto It = std::make_pair(BB->getLayoutIndex(), SuccBB->getLayoutIndex());
-      JumpCounts.push_back(std::make_pair(It, BI->Count));
+      JumpCounts.push_back(
+          {BB->getLayoutIndex(), SuccBB->getLayoutIndex(), BI->Count});
       ++BI;
     }
   }
 
   // Run the layout algorithm
-  auto Result = applyExtTspLayout(BlockSizes, BlockCounts, JumpCounts);
+  auto Result =
+      codelayout::computeExtTspLayout(BlockSizes, BlockCounts, JumpCounts);
   Order.reserve(BF.getLayout().block_size());
   for (uint64_t R : Result)
     Order.push_back(OrigOrder[R]);