verilator/src/V3PatternStats.cpp

130 lines
4.8 KiB
C++

// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Dump data structure pattern frequencies for analysis
//
// Code available from: https://verilator.org
//
//*************************************************************************
//
// 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-FileCopyrightText: 2003-2026 Wilson Snyder
// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
//
//*************************************************************************
#include "V3PchAstNoMT.h"
#include "V3Ast.h"
#include "V3AstPatterns.h"
#include "V3Dfg.h"
#include "V3DfgPasses.h"
#include "V3File.h"
#include <memory>
#include <unordered_map>
#include <vector>
VL_DEFINE_DEBUG_FUNCTIONS;
//============================================================================
// Accumulates and dumps the pattern statistics
class V3PatternStats VL_NOT_FINAL {
public:
static constexpr uint32_t MIN_PATTERN_DEPTH = 1;
static constexpr uint32_t MAX_PATTERN_DEPTH = 4;
private:
const std::string m_what; // Description of what is being dumped
// Maps from pattern to the number of times it appears, for each pattern depth
std::vector<std::unordered_map<std::string, size_t>> m_patternCounts{MAX_PATTERN_DEPTH + 1};
void dump(std::ostream& os) {
using Line = std::pair<std::string, size_t>;
for (uint32_t i = MIN_PATTERN_DEPTH; i <= MAX_PATTERN_DEPTH; ++i) {
os << m_what << " patterns with depth " << i << '\n';
// Pick up pattern accumulators with given depth
auto& patternCounts = m_patternCounts[i];
// Remove patterns also present at shallower depths
for (uint32_t j = MIN_PATTERN_DEPTH; j < i; ++j) {
for (const auto& pair : m_patternCounts[j]) patternCounts.erase(pair.first);
}
// Sort patterns, first by descending frequency, then lexically
std::vector<Line> lines;
lines.reserve(patternCounts.size());
for (const auto& pair : patternCounts) lines.emplace_back(pair);
std::sort(lines.begin(), lines.end(), [](const Line& a, const Line& b) {
if (a.second != b.second) return a.second > b.second;
return a.first < b.first;
});
// Print each pattern
for (const auto& line : lines) {
os << ' ' << std::setw(12) << std::right << line.second;
os << ' ' << std::left << line.first << '\n';
}
// Trailing new-line to separate sections
os << '\n';
}
}
public:
V3PatternStats(const std::string& what)
: m_what{what} {}
~V3PatternStats() = default;
void accumulate(const std::string& pattern, uint32_t depth) {
m_patternCounts[depth][pattern] += 1;
}
void dumpToFile(const std::string& filename) {
// Open, write, close
const std::unique_ptr<std::ofstream> ofp{V3File::new_ofstream(filename)};
if (ofp->fail()) v3fatal("Can't write file: " << filename);
dump(*ofp);
}
};
//============================================================================
// V3AstPatterns top level
void V3AstPatterns::dumpAll(const AstNetlist* nodep, const std::string& suffix) {
UINFO(2, __FUNCTION__ << ":");
V3PatternStats patternStats{"AST"};
nodep->foreach([&](const AstNodeExpr* exprp) {
for (uint32_t i = V3PatternStats::MIN_PATTERN_DEPTH;
i <= V3PatternStats::MAX_PATTERN_DEPTH; ++i) {
patternStats.accumulate(exprp->patternString(i), i);
}
});
const std::string fileName = v3Global.opt.hierTopDataDir() + "/" + v3Global.opt.prefix()
+ "__ast_patterns_" + suffix + ".txt";
patternStats.dumpToFile(fileName);
V3Global::dumpCheckGlobalTree("astpatterns", 0, false, false);
}
//============================================================================
// V3DfgPasses top level
void V3DfgPasses::dumpPatterns(const std::vector<std::unique_ptr<DfgGraph>>& graphs,
const std::string& suffix) {
V3PatternStats patternStats{"DFG"};
for (auto& cp : graphs) {
cp->forEachVertex([&](const DfgVertex& vtx) {
for (uint32_t i = V3PatternStats::MIN_PATTERN_DEPTH;
i <= V3PatternStats::MAX_PATTERN_DEPTH; ++i) {
patternStats.accumulate(vtx.patternString(i), i);
}
});
}
const std::string fileName = v3Global.opt.hierTopDataDir() + "/" + v3Global.opt.prefix()
+ "__dfg_patterns" + suffix + ".txt";
patternStats.dumpToFile(fileName);
}