1 //===---------------------- Stage.h -----------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 /// \file
10 ///
11 /// This file defines a stage.
12 /// A chain of stages compose an instruction pipeline.
13 ///
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_TOOLS_LLVM_MCA_STAGE_H
17 #define LLVM_TOOLS_LLVM_MCA_STAGE_H
18 
19 #include "HWEventListener.h"
20 #include <set>
21 
22 namespace mca {
23 
24 class InstRef;
25 
26 class Stage {
27   Stage(const Stage &Other) = delete;
28   Stage &operator=(const Stage &Other) = delete;
29   std::set<HWEventListener *> Listeners;
30 
31 protected:
getListeners()32   const std::set<HWEventListener *> &getListeners() const { return Listeners; }
33 
34 public:
35   Stage();
36   virtual ~Stage() = default;
37 
38   /// Called prior to preExecute to ensure that the stage has items that it
39   /// is to process.  For example, a FetchStage might have more instructions
40   /// that need to be processed, or a RCU might have items that have yet to
41   /// retire.
42   virtual bool hasWorkToComplete() const = 0;
43 
44   /// Called once at the start of each cycle.  This can be used as a setup
45   /// phase to prepare for the executions during the cycle.
cycleStart()46   virtual void cycleStart() {}
47 
48   /// Called once at the end of each cycle.
cycleEnd()49   virtual void cycleEnd() {}
50 
51   /// Called prior to executing the list of stages.
52   /// This can be called multiple times per cycle.
preExecute()53   virtual void preExecute() {}
54 
55   /// Called as a cleanup and finalization phase after each execution.
56   /// This will only be called if all stages return a success from their
57   /// execute callback.  This can be called multiple times per cycle.
postExecute()58   virtual void postExecute() {}
59 
60   /// The primary action that this stage performs.
61   /// Returning false prevents successor stages from having their 'execute'
62   /// routine called.  This can be called multiple times during a single cycle.
63   virtual bool execute(InstRef &IR) = 0;
64 
65   /// Add a listener to receive callbacks during the execution of this stage.
66   void addListener(HWEventListener *Listener);
67 
68   /// Notify listeners of a particular hardware event.
notifyEvent(const EventT & Event)69   template <typename EventT> void notifyEvent(const EventT &Event) {
70     for (HWEventListener *Listener : Listeners)
71       Listener->onEvent(Event);
72   }
73 };
74 
75 } // namespace mca
76 #endif // LLVM_TOOLS_LLVM_MCA_STAGE_H
77