77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
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//===--------------------- Pipeline.h ---------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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/// \file
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///
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/// This file implements an ordered container of stages that simulate the
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/// pipeline of a hardware backend.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_MCA_PIPELINE_H
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#define LLVM_MCA_PIPELINE_H
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#include "llvm/MCA/Stages/Stage.h"
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#include "llvm/Support/Error.h"
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namespace llvm {
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namespace mca {
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class HWEventListener;
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/// A pipeline for a specific subtarget.
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///
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/// It emulates an out-of-order execution of instructions. Instructions are
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/// fetched from a MCInst sequence managed by an initial 'Fetch' stage.
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/// Instructions are firstly fetched, then dispatched to the schedulers, and
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/// then executed.
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///
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/// This class tracks the lifetime of an instruction from the moment where
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/// it gets dispatched to the schedulers, to the moment where it finishes
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/// executing and register writes are architecturally committed.
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/// In particular, it monitors changes in the state of every instruction
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/// in flight.
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///
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/// Instructions are executed in a loop of iterations. The number of iterations
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/// is defined by the SourceMgr object, which is managed by the initial stage
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/// of the instruction pipeline.
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///
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/// The Pipeline entry point is method 'run()' which executes cycles in a loop
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/// until there are new instructions to dispatch, and not every instruction
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/// has been retired.
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///
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/// Internally, the Pipeline collects statistical information in the form of
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/// histograms. For example, it tracks how the dispatch group size changes
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/// over time.
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class Pipeline {
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Pipeline(const Pipeline &P) = delete;
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Pipeline &operator=(const Pipeline &P) = delete;
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/// An ordered list of stages that define this instruction pipeline.
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SmallVector<std::unique_ptr<Stage>, 8> Stages;
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std::set<HWEventListener *> Listeners;
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unsigned Cycles;
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Error runCycle();
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bool hasWorkToProcess();
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void notifyCycleBegin();
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void notifyCycleEnd();
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public:
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Pipeline() : Cycles(0) {}
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void appendStage(std::unique_ptr<Stage> S);
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/// Returns the total number of simulated cycles.
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Expected<unsigned> run();
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void addEventListener(HWEventListener *Listener);
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};
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} // namespace mca
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} // namespace llvm
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#endif // LLVM_MCA_PIPELINE_H
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