verilator/src/V3Scoreboard.cpp

97 lines
3.5 KiB
C++

// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Threading's element scoreboarding
//
// Code available from: https://verilator.org
//
//*************************************************************************
//
// Copyright 2003-2024 by Wilson Snyder. This program is free software; you
// can redistribute it and/or modify it under the terms of either the GNU
// Lesser General Public License Version 3 or the Perl Artistic License
// Version 2.0.
// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
//
//*************************************************************************
#include "V3PchAstNoMT.h" // VL_MT_DISABLED_CODE_UNIT
#include "V3Scoreboard.h"
class ScoreboardTestElem;
struct Key final {
// Node: Structure layout chosen to minimize padding in PairingHeao<*>::Node
uint64_t m_id; // Unique ID part of edge score
uint32_t m_score; // Score part of ID
bool operator<(const Key& other) const {
// First by Score then by ID, but notice that we want minimums using a max-heap, so reverse
return m_score > other.m_score || (m_score == other.m_score && m_id > other.m_id);
}
};
using Scoreboard = V3Scoreboard<ScoreboardTestElem, Key>;
class ScoreboardTestElem final : public Scoreboard::Node {
public:
uint32_t m_newScore;
// CONSTRUCTORS
explicit ScoreboardTestElem(uint32_t score)
: m_newScore{score} {
m_key.m_score = m_newScore;
static uint32_t s_serial = 0;
m_key.m_id = ++s_serial;
}
ScoreboardTestElem() = default;
uint64_t id() const { return m_key.m_id; }
void rescore() { m_key.m_score = m_newScore; }
uint32_t score() const { return m_key.m_score; }
static ScoreboardTestElem* heapNodeToElem(Scoreboard::Node* nodep) {
return static_cast<ScoreboardTestElem*>(nodep);
}
};
void V3ScoreboardBase::selfTest() {
Scoreboard sb;
UASSERT(!sb.needsRescore(), "SelfTest: Empty sb should not need rescore.");
ScoreboardTestElem e1{10};
ScoreboardTestElem e2{20};
ScoreboardTestElem e3{30};
sb.add(&e1);
sb.add(&e2);
sb.add(&e3);
UASSERT(sb.needsRescore(), "SelfTest: Newly filled sb should need a rescore.");
UASSERT(sb.needsRescore(&e1), "SelfTest: Individual newly-added element should need rescore");
UASSERT(nullptr == sb.best(),
"SelfTest: Newly filled sb should have nothing eligible for Bestp()");
sb.rescore();
UASSERT(!sb.needsRescore(), "SelfTest: Newly rescored sb should not need rescore");
UASSERT(!sb.needsRescore(&e1),
"SelfTest: Newly rescored sb should not need an element rescored");
UASSERT(&e1 == sb.best(), "SelfTest: Should return element with lowest (best) score");
// Change one element's score
sb.hintScoreChanged(&e2);
e2.m_newScore = 21;
UASSERT(sb.needsRescore(&e2), "SelfTest: Should need rescore on elem after hintScoreChanged");
// Remove an element
UASSERT(sb.contains(&e1), "SelfTest: e1 should be there");
sb.remove(&e1);
UASSERT(!sb.contains(&e1), "SelfTest: e1 should be gone");
UASSERT(sb.contains(&e2), "SelfTest: e2 should be there, despite needing rescore");
// Now e3 should be our best-scoring element, even though
// e2 has a better score, since e2 is pending rescore.
UASSERT(&e3 == sb.best(), "SelfTest: Expect e3 as best element with known score.");
sb.rescore();
UASSERT(&e2 == sb.best(), "SelfTest: Expect e2 as best element again after Rescore");
}