1//===--------------------- Pipeline.cpp -------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8/// \file
9///
10/// This file implements an ordered container of stages that simulate the
11/// pipeline of a hardware backend.
12///
13//===----------------------------------------------------------------------===//
14
15#include "llvm/MCA/Pipeline.h"
16#include "llvm/MCA/HWEventListener.h"
17#include "llvm/Support/Debug.h"
18
19namespace llvm {
20namespace mca {
21
22#define DEBUG_TYPE "llvm-mca"
23
24void Pipeline::addEventListener(HWEventListener *Listener) {
25 if (Listener)
26 Listeners.insert(x: Listener);
27 for (auto &S : Stages)
28 S->addListener(Listener);
29}
30
31bool Pipeline::hasWorkToProcess() {
32 return any_of(Range&: Stages, P: [](const std::unique_ptr<Stage> &S) {
33 return S->hasWorkToComplete();
34 });
35}
36
37Expected<unsigned> Pipeline::run() {
38 assert(!Stages.empty() && "Unexpected empty pipeline found!");
39
40 do {
41 if (!isPaused())
42 notifyCycleBegin();
43 if (Error Err = runCycle())
44 return std::move(Err);
45 notifyCycleEnd();
46 ++Cycles;
47 } while (hasWorkToProcess());
48
49 return Cycles;
50}
51
52Error Pipeline::runCycle() {
53 Error Err = ErrorSuccess();
54 // Update stages before we start processing new instructions.
55 for (auto I = Stages.rbegin(), E = Stages.rend(); I != E && !Err; ++I) {
56 const std::unique_ptr<Stage> &S = *I;
57 if (isPaused())
58 Err = S->cycleResume();
59 else
60 Err = S->cycleStart();
61 }
62
63 CurrentState = State::Started;
64
65 // Now fetch and execute new instructions.
66 InstRef IR;
67 Stage &FirstStage = *Stages[0];
68 while (!Err && FirstStage.isAvailable(IR))
69 Err = FirstStage.execute(IR);
70
71 if (Err.isA<InstStreamPause>()) {
72 CurrentState = State::Paused;
73 return Err;
74 }
75
76 // Update stages in preparation for a new cycle.
77 for (const std::unique_ptr<Stage> &S : Stages) {
78 Err = S->cycleEnd();
79 if (Err)
80 break;
81 }
82
83 return Err;
84}
85
86void Pipeline::appendStage(std::unique_ptr<Stage> S) {
87 assert(S && "Invalid null stage in input!");
88 if (!Stages.empty()) {
89 Stage *Last = Stages.back().get();
90 Last->setNextInSequence(S.get());
91 }
92
93 Stages.push_back(Elt: std::move(S));
94}
95
96void Pipeline::notifyCycleBegin() {
97 LLVM_DEBUG(dbgs() << "\n[E] Cycle begin: " << Cycles << '\n');
98 for (HWEventListener *Listener : Listeners)
99 Listener->onCycleBegin();
100}
101
102void Pipeline::notifyCycleEnd() {
103 LLVM_DEBUG(dbgs() << "[E] Cycle end: " << Cycles << "\n");
104 for (HWEventListener *Listener : Listeners)
105 Listener->onCycleEnd();
106}
107} // namespace mca.
108} // namespace llvm
109