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3e93a21a21
There's no reason to do further stages of analysis to propagate coldness if there wasn't any found in Stage 1.
90 lines
2.8 KiB
C++
90 lines
2.8 KiB
C++
//===--- ColdBlockInfo.h - Fast/slow path analysis for SIL CFG --*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_SILOPTIMIZER_ANALYSIS_COLDBLOCKS_H
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#define SWIFT_SILOPTIMIZER_ANALYSIS_COLDBLOCKS_H
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#include "llvm/ADT/DenseMap.h"
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#include "swift/SIL/SILValue.h"
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#include "swift/Basic/FixedBitSet.h"
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namespace swift {
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class DominanceAnalysis;
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class PostDominanceAnalysis;
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class SILBasicBlock;
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class CondBranchInst;
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/// Cache a set of basic blocks that have been determined to be cold or hot.
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///
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/// This does not inherit from SILAnalysis because it is not worth preserving
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/// across passes.
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class ColdBlockInfo {
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public:
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// Represents the temperatures of edges flowing into a block.
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//
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// T = "top" -- both warm and cold edges
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// / \
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// Warm Cold
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// \ /
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// B = "bottom" -- neither warm or cold edges
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struct State {
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// Each state kind, as an integer, is its position in any bit vectors.
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enum Temperature {
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Warm = 0,
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Cold = 1
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};
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// Number of states, excluding Top or Bottom, in this flow problem.
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static constexpr unsigned NumStates = 2;
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};
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using Energy = FixedBitSet<State::NumStates, State::Temperature>;
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private:
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DominanceAnalysis *DA;
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PostDominanceAnalysis *PDA;
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/// Each block in this map has been determined to be cold and/or warm.
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/// Make sure to always use the set/resetToCold methods to update this!
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llvm::DenseMap<const SILBasicBlock*, Energy> EnergyMap;
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// This is a cache and shouldn't be copied around.
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ColdBlockInfo(const ColdBlockInfo &) = delete;
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ColdBlockInfo &operator=(const ColdBlockInfo &) = delete;
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LLVM_DUMP_METHOD void dump() const;
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/// Tracks whether any information was changed in the energy map.
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bool changedMap = false;
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void resetToCold(const SILBasicBlock *BB);
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void set(const SILBasicBlock *BB, State::Temperature temp);
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using ExpectedValue = std::optional<bool>;
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void setExpectedCondition(CondBranchInst *CondBranch, ExpectedValue value);
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ExpectedValue searchForExpectedValue(SILValue Cond,
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unsigned recursionDepth = 0);
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void searchForExpectedValue(CondBranchInst *CondBranch);
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bool inferFromEdgeProfile(SILBasicBlock *BB);
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public:
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ColdBlockInfo(DominanceAnalysis *DA, PostDominanceAnalysis *PDA);
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void analyze(SILFunction *F);
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bool isCold(const SILBasicBlock *BB) const;
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};
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} // end namespace swift
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#endif
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