vendor/llvm/llvm-trunk-r375505vendor/llvm

1 files changed, 84 insertions, 0 deletions

diff --git a/include/llvm/ExecutionEngine/Orc/SpeculateAnalyses.h b/include/llvm/ExecutionEngine/Orc/SpeculateAnalyses.h
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index 000000000000..cf57b63b6448
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+++ b/include/llvm/ExecutionEngine/Orc/SpeculateAnalyses.h
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+//===-- SpeculateAnalyses.h  --*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// \file
+/// Contains the Analyses and Result Interpretation to select likely functions
+/// to Speculatively compile before they are called. [Purely Experimentation]
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_SPECULATEANALYSES_H
+#define LLVM_EXECUTIONENGINE_ORC_SPECULATEANALYSES_H
+
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/ExecutionEngine/Orc/Core.h"
+#include "llvm/ExecutionEngine/Orc/Speculation.h"
+
+#include <vector>
+
+namespace llvm {
+
+namespace orc {
+
+// Provides common code.
+class SpeculateQuery {
+protected:
+  void findCalles(const BasicBlock *, DenseSet<StringRef> &);
+  bool isStraightLine(const Function &F);
+
+public:
+  using ResultTy = Optional<DenseMap<StringRef, DenseSet<StringRef>>>;
+};
+
+// Direct calls in high frequency basic blocks are extracted.
+class BlockFreqQuery : public SpeculateQuery {
+  size_t numBBToGet(size_t);
+
+public:
+  // Find likely next executables based on IR Block Frequency
+  ResultTy operator()(Function &F);
+};
+
+// This Query generates a sequence of basic blocks which follows the order of
+// execution.
+// A handful of BB with higher block frequencies are taken, then path to entry
+// and end BB are discovered by traversing up & down the CFG.
+class SequenceBBQuery : public SpeculateQuery {
+  struct WalkDirection {
+    bool Upward = true, Downward = true;
+    // the block associated contain a call
+    bool CallerBlock = false;
+  };
+
+public:
+  using VisitedBlocksInfoTy = DenseMap<const BasicBlock *, WalkDirection>;
+  using BlockListTy = SmallVector<const BasicBlock *, 8>;
+  using BackEdgesInfoTy =
+      SmallVector<std::pair<const BasicBlock *, const BasicBlock *>, 8>;
+  using BlockFreqInfoTy =
+      SmallVector<std::pair<const BasicBlock *, uint64_t>, 8>;
+
+private:
+  std::size_t getHottestBlocks(std::size_t TotalBlocks);
+  BlockListTy rearrangeBB(const Function &, const BlockListTy &);
+  BlockListTy queryCFG(Function &, const BlockListTy &);
+  void traverseToEntryBlock(const BasicBlock *, const BlockListTy &,
+                            const BackEdgesInfoTy &,
+                            const BranchProbabilityInfo *,
+                            VisitedBlocksInfoTy &);
+  void traverseToExitBlock(const BasicBlock *, const BlockListTy &,
+                           const BackEdgesInfoTy &,
+                           const BranchProbabilityInfo *,
+                           VisitedBlocksInfoTy &);
+
+public:
+  ResultTy operator()(Function &F);
+};
+
+} // namespace orc
+} // namespace llvm
+
+#endif // LLVM_EXECUTIONENGINE_ORC_SPECULATEANALYSES_H