1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/tools/reorder/grope.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,532 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +/*
1.9 +
1.10 + A program that computes a function ordering for an executable based
1.11 + on runtime profile information.
1.12 +
1.13 + This program is directly based on work done by Roger Chickering
1.14 + <rogc@netscape.com> in
1.15 +
1.16 + <http://bugzilla.mozilla.org/show_bug.cgi?id=65845>
1.17 +
1.18 + to implement Nat Friedman's <nat@nat.org> `grope',
1.19 +
1.20 + _GNU Rope - A Subroutine Position Optimizer_
1.21 + <http://www.hungry.com/~shaver/grope/grope.ps>
1.22 +
1.23 + Specifically, it implements the procedure re-ordering algorithm
1.24 + described in:
1.25 +
1.26 + K. Pettis and R. Hansen. ``Profile-Guided Core Position.'' In
1.27 + _Proceedings of the Int. Conference on Programming Language Design
1.28 + and Implementation_, pages 16-27, June 1990.
1.29 +
1.30 + */
1.31 +
1.32 +#include <assert.h>
1.33 +#include <fstream>
1.34 +#include <hash_set>
1.35 +#include <map>
1.36 +#include <set>
1.37 +#include <list>
1.38 +#include <vector>
1.39 +#include <limits.h>
1.40 +#include <unistd.h>
1.41 +#include <stdio.h>
1.42 +#include <fcntl.h>
1.43 +
1.44 +#include "elf_symbol_table.h"
1.45 +
1.46 +#define _GNU_SOURCE
1.47 +#include <getopt.h>
1.48 +
1.49 +elf_symbol_table symtab;
1.50 +
1.51 +// Straight outta plhash.c!
1.52 +#define GOLDEN_RATIO 0x9E3779B9U
1.53 +
1.54 +struct hash<const Elf32_Sym *>
1.55 +{
1.56 + size_t operator()(const Elf32_Sym *sym) const {
1.57 + return (reinterpret_cast<size_t>(sym) >> 4) * GOLDEN_RATIO; }
1.58 +};
1.59 +
1.60 +typedef unsigned int call_count_t;
1.61 +
1.62 +struct call_graph_arc
1.63 +{
1.64 + const Elf32_Sym *m_from;
1.65 + const Elf32_Sym *m_to;
1.66 + call_count_t m_count;
1.67 +
1.68 + call_graph_arc(const Elf32_Sym *left, const Elf32_Sym *right, call_count_t count = 0)
1.69 + : m_count(count)
1.70 + {
1.71 + assert(left != right);
1.72 +
1.73 + if (left > right) {
1.74 + m_from = left;
1.75 + m_to = right;
1.76 + }
1.77 + else {
1.78 + m_from = right;
1.79 + m_to = left;
1.80 + }
1.81 + }
1.82 +
1.83 + friend bool
1.84 + operator==(const call_graph_arc &lhs, const call_graph_arc &rhs)
1.85 + {
1.86 + return (lhs.m_from == rhs.m_from) && (lhs.m_to == rhs.m_to);
1.87 + }
1.88 +
1.89 + friend ostream &
1.90 + operator<<(ostream &out, const call_graph_arc &arc)
1.91 + {
1.92 + out << &arc << ": ";
1.93 + out.form("<(%s %s) %d>",
1.94 + symtab.get_symbol_name(arc.m_from),
1.95 + symtab.get_symbol_name(arc.m_to),
1.96 + arc.m_count);
1.97 +
1.98 + return out;
1.99 + }
1.100 +};
1.101 +
1.102 +struct hash<call_graph_arc *>
1.103 +{
1.104 + size_t
1.105 + operator()(const call_graph_arc* arc) const
1.106 + {
1.107 + size_t result;
1.108 + result = reinterpret_cast<unsigned long>(arc->m_from);
1.109 + result ^= reinterpret_cast<unsigned long>(arc->m_to) >> 16;
1.110 + result ^= reinterpret_cast<unsigned long>(arc->m_to) << 16;
1.111 + result *= GOLDEN_RATIO;
1.112 + return result;
1.113 + }
1.114 +};
1.115 +
1.116 +struct equal_to<call_graph_arc *>
1.117 +{
1.118 + bool
1.119 + operator()(const call_graph_arc* lhs, const call_graph_arc *rhs) const
1.120 + {
1.121 + return *lhs == *rhs;
1.122 + }
1.123 +};
1.124 +
1.125 +typedef hash_set<call_graph_arc *> arc_container_t;
1.126 +arc_container_t arcs;
1.127 +
1.128 +typedef multimap<const Elf32_Sym *, call_graph_arc *> arc_map_t;
1.129 +arc_map_t from_map;
1.130 +arc_map_t to_map;
1.131 +
1.132 +struct less_call_graph_arc_count
1.133 +{
1.134 + bool
1.135 + operator()(const call_graph_arc *lhs, const call_graph_arc *rhs) const
1.136 + {
1.137 + if (lhs->m_count == rhs->m_count) {
1.138 + if (lhs->m_from == rhs->m_from)
1.139 + return lhs->m_to > rhs->m_to;
1.140 +
1.141 + return lhs->m_from > rhs->m_from;
1.142 + }
1.143 + return lhs->m_count > rhs->m_count;
1.144 + }
1.145 +};
1.146 +
1.147 +typedef set<call_graph_arc *, less_call_graph_arc_count> arc_count_index_t;
1.148 +
1.149 +bool opt_debug = false;
1.150 +const char *opt_out = "order.out";
1.151 +int opt_tick = 0;
1.152 +bool opt_verbose = false;
1.153 +int opt_window = 16;
1.154 +
1.155 +static struct option long_options[] = {
1.156 + { "debug", no_argument, 0, 'd' },
1.157 + { "exe", required_argument, 0, 'e' },
1.158 + { "help", no_argument, 0, '?' },
1.159 + { "out", required_argument, 0, 'o' },
1.160 + { "tick", optional_argument, 0, 't' },
1.161 + { "verbose", no_argument, 0, 'v' },
1.162 + { "window", required_argument, 0, 'w' },
1.163 + { 0, 0, 0, 0 }
1.164 +};
1.165 +
1.166 +//----------------------------------------------------------------------
1.167 +
1.168 +static void
1.169 +usage(const char *name)
1.170 +{
1.171 + cerr << "usage: " << name << " [options] [<file> ...]" << endl;
1.172 + cerr << " Options:" << endl;
1.173 + cerr << " --debug, -d" << endl;
1.174 + cerr << " Print lots of verbose debugging cruft." << endl;
1.175 + cerr << " --exe=<image>, -e <image> (required)" << endl;
1.176 + cerr << " Specify the executable image from which to read symbol information." << endl;
1.177 + cerr << " --help, -?" << endl;
1.178 + cerr << " Print this message and exit." << endl;
1.179 + cerr << " --out=<file>, -o <file>" << endl;
1.180 + cerr << " Specify the output file to which to dump the symbol ordering of the" << endl;
1.181 + cerr << " best individual (default is `order.out')." << endl;
1.182 + cerr << " --tick[=<num>], -t [<num>]" << endl;
1.183 + cerr << " When reading address data, print a dot to stderr every <num>th" << endl;
1.184 + cerr << " address processed from the call trace. If specified with no argument," << endl;
1.185 + cerr << " a dot will be printed for every million addresses processed." << endl;
1.186 + cerr << " --verbose, -v" << endl;
1.187 + cerr << " Issue progress messages to stderr." << endl;
1.188 + cerr << " --window=<num>, -w <num>" << endl;
1.189 + cerr << " Use a sliding window instead of pagination to score orderings." << endl;
1.190 +}
1.191 +
1.192 +/**
1.193 + * Using the symbol table, map a stream of address references into a
1.194 + * callgraph.
1.195 + */
1.196 +static void
1.197 +map_addrs(int fd)
1.198 +{
1.199 + long long total_calls = 0;
1.200 + typedef list<const Elf32_Sym *> window_t;
1.201 +
1.202 + window_t window;
1.203 + int window_size = 0;
1.204 + unsigned int buf[128];
1.205 + ssize_t cb;
1.206 +
1.207 + while ((cb = read(fd, buf, sizeof buf)) > 0) {
1.208 + if (cb % sizeof buf[0])
1.209 + fprintf(stderr, "unaligned read\n");
1.210 +
1.211 + unsigned int *addr = buf;
1.212 + unsigned int *limit = buf + (cb / 4);
1.213 +
1.214 + for (; addr < limit; ++addr) {
1.215 + const Elf32_Sym *sym = symtab.lookup(*addr);
1.216 + if (! sym)
1.217 + continue;
1.218 +
1.219 + ++total_calls;
1.220 +
1.221 + window.push_front(sym);
1.222 +
1.223 + if (window_size >= opt_window)
1.224 + window.pop_back();
1.225 + else
1.226 + ++window_size;
1.227 +
1.228 + window_t::const_iterator i = window.begin();
1.229 + window_t::const_iterator end = window.end();
1.230 + for (; i != end; ++i) {
1.231 + if (sym != *i) {
1.232 + call_graph_arc *arc;
1.233 + call_graph_arc key(sym, *i);
1.234 + arc_container_t::iterator iter = arcs.find(&key);
1.235 + if (iter == arcs.end()) {
1.236 + arc = new call_graph_arc(sym, *i);
1.237 + arcs.insert(arc);
1.238 + from_map.insert(arc_map_t::value_type(arc->m_from, arc));
1.239 + to_map.insert(arc_map_t::value_type(arc->m_to, arc));
1.240 + }
1.241 + else
1.242 + arc = const_cast<call_graph_arc *>(*iter);
1.243 +
1.244 + ++(arc->m_count);
1.245 + }
1.246 + }
1.247 +
1.248 + if (opt_verbose && opt_tick && (total_calls % opt_tick == 0)) {
1.249 + cerr << ".";
1.250 + flush(cerr);
1.251 + }
1.252 + }
1.253 + }
1.254 +
1.255 + if (opt_verbose) {
1.256 + if (opt_tick)
1.257 + cerr << endl;
1.258 +
1.259 + cerr << "Total calls: " << total_calls << endl;
1.260 + }
1.261 +}
1.262 +
1.263 +static void
1.264 +remove_from(arc_map_t& map, const Elf32_Sym *sym, const call_graph_arc *arc)
1.265 +{
1.266 + pair<arc_map_t::iterator, arc_map_t::iterator> p
1.267 + = map.equal_range(sym);
1.268 +
1.269 + for (arc_map_t::iterator i = p.first; i != p.second; ++i) {
1.270 + if (i->second == arc) {
1.271 + map.erase(i);
1.272 + break;
1.273 + }
1.274 + }
1.275 +}
1.276 +
1.277 +/**
1.278 + * The main program
1.279 + */
1.280 +int
1.281 +main(int argc, char *argv[])
1.282 +{
1.283 + const char *opt_exe = 0;
1.284 +
1.285 + int c;
1.286 + while (1) {
1.287 + int option_index = 0;
1.288 + c = getopt_long(argc, argv, "?de:o:t:vw:", long_options, &option_index);
1.289 +
1.290 + if (c < 0)
1.291 + break;
1.292 +
1.293 + switch (c) {
1.294 + case '?':
1.295 + usage(argv[0]);
1.296 + return 0;
1.297 +
1.298 + case 'd':
1.299 + opt_debug = true;
1.300 + break;
1.301 +
1.302 + case 'e':
1.303 + opt_exe = optarg;
1.304 + break;
1.305 +
1.306 + case 'o':
1.307 + opt_out = optarg;
1.308 + break;
1.309 +
1.310 + case 't':
1.311 + opt_tick = optarg ? atoi(optarg) : 1000000;
1.312 + break;
1.313 +
1.314 + case 'v':
1.315 + opt_verbose = true;
1.316 + break;
1.317 +
1.318 + case 'w':
1.319 + opt_window = atoi(optarg);
1.320 + if (opt_window <= 0) {
1.321 + cerr << "invalid window size: " << opt_window << endl;
1.322 + return 1;
1.323 + }
1.324 + break;
1.325 +
1.326 + default:
1.327 + usage(argv[0]);
1.328 + return 1;
1.329 + }
1.330 + }
1.331 +
1.332 + // Make sure an image was specified
1.333 + if (! opt_exe) {
1.334 + usage(argv[0]);
1.335 + return 1;
1.336 + }
1.337 +
1.338 + // Read the sym table.
1.339 + symtab.init(opt_exe);
1.340 +
1.341 + // Process addresses to construct the weighted call graph.
1.342 + if (optind >= argc) {
1.343 + map_addrs(STDIN_FILENO);
1.344 + }
1.345 + else {
1.346 + do {
1.347 + int fd = open(argv[optind], O_RDONLY);
1.348 + if (fd < 0) {
1.349 + perror(argv[optind]);
1.350 + return 1;
1.351 + }
1.352 +
1.353 + map_addrs(fd);
1.354 + close(fd);
1.355 + } while (++optind < argc);
1.356 + }
1.357 +
1.358 + // Emit the ordering.
1.359 + ofstream out(opt_out);
1.360 +
1.361 + // Collect all of the arcs into a sorted container, with arcs
1.362 + // having the largest weight at the front.
1.363 + arc_count_index_t sorted_arcs(arcs.begin(), arcs.end());
1.364 +
1.365 + while (sorted_arcs.size()) {
1.366 + if (opt_debug) {
1.367 + cerr << "==========================================" << endl << endl;
1.368 +
1.369 + cerr << "Sorted Arcs:" << endl;
1.370 + for (arc_count_index_t::const_iterator iter = sorted_arcs.begin();
1.371 + iter != sorted_arcs.end();
1.372 + ++iter) {
1.373 + cerr << **iter << endl;
1.374 + }
1.375 +
1.376 + cerr << endl << "Arc Container:" << endl;
1.377 + for (arc_container_t::const_iterator iter = arcs.begin();
1.378 + iter != arcs.end();
1.379 + ++iter) {
1.380 + cerr << **iter << endl;
1.381 + }
1.382 +
1.383 + cerr << endl << "From Map:" << endl;
1.384 + for (arc_map_t::const_iterator iter = from_map.begin();
1.385 + iter != from_map.end();
1.386 + ++iter) {
1.387 + cerr << symtab.get_symbol_name(iter->first) << ": " << *(iter->second) << endl;
1.388 + }
1.389 +
1.390 + cerr << endl << "To Map:" << endl;
1.391 + for (arc_map_t::const_iterator iter = to_map.begin();
1.392 + iter != to_map.end();
1.393 + ++iter) {
1.394 + cerr << symtab.get_symbol_name(iter->first) << ": " << *(iter->second) << endl;
1.395 + }
1.396 +
1.397 + cerr << endl;
1.398 + }
1.399 +
1.400 + // The first arc in the sorted set will have the largest
1.401 + // weight. Pull it out, and emit its sink.
1.402 + arc_count_index_t::iterator max = sorted_arcs.begin();
1.403 + call_graph_arc *arc = const_cast<call_graph_arc *>(*max);
1.404 +
1.405 + sorted_arcs.erase(max);
1.406 +
1.407 + if (opt_debug)
1.408 + cerr << "pulling " << *arc << endl;
1.409 +
1.410 + arcs.erase(arc);
1.411 + remove_from(from_map, arc->m_from, arc);
1.412 + remove_from(to_map, arc->m_to, arc);
1.413 +
1.414 + out << symtab.get_symbol_name(arc->m_to) << endl;
1.415 +
1.416 + // Merge arc->m_to into arc->m_from. First, modify anything
1.417 + // that used to point to arc->m_to to point to arc->m_from.
1.418 + typedef list<call_graph_arc *> arc_list_t;
1.419 + arc_list_t map_add_queue;
1.420 +
1.421 + pair<arc_map_t::iterator, arc_map_t::iterator> p;
1.422 +
1.423 + // Find all the arcs that point to arc->m_to.
1.424 + p = to_map.equal_range(arc->m_to);
1.425 + for (arc_map_t::iterator i = p.first; i != p.second; ++i) {
1.426 + // Remove the arc that points to arc->m_to (`doomed') from
1.427 + // all of our indicies.
1.428 + call_graph_arc *doomed = i->second;
1.429 + const Elf32_Sym *source = doomed->m_from;
1.430 +
1.431 + sorted_arcs.erase(doomed);
1.432 + arcs.erase(doomed);
1.433 + remove_from(from_map, source, doomed);
1.434 + // N.B. that `doomed' will be removed from the `to_map'
1.435 + // after the loop completes.
1.436 +
1.437 + // Create a new (or locate an existing) arc whose source
1.438 + // was the doomed arc's source, and whose sink is
1.439 + // arc->m_from (i.e., the node that subsumed arc->m_to).
1.440 + call_graph_arc *merge;
1.441 + call_graph_arc key = call_graph_arc(source, arc->m_from);
1.442 + arc_container_t::iterator iter = arcs.find(&key);
1.443 +
1.444 + if (iter == arcs.end()) {
1.445 + merge = new call_graph_arc(source, arc->m_from);
1.446 +
1.447 + arcs.insert(merge);
1.448 + from_map.insert(arc_map_t::value_type(merge->m_from, merge));
1.449 + map_add_queue.push_back(merge);
1.450 + }
1.451 + else {
1.452 + // We found an existing arc: temporarily remove it
1.453 + // from the sorted index.
1.454 + merge = const_cast<call_graph_arc *>(*iter);
1.455 + sorted_arcs.erase(merge);
1.456 + }
1.457 +
1.458 + // Include the doomed arc's weight in the merged arc, and
1.459 + // (re-)insert it into the sorted index.
1.460 + merge->m_count += doomed->m_count;
1.461 + sorted_arcs.insert(merge);
1.462 +
1.463 + delete doomed;
1.464 + }
1.465 +
1.466 + to_map.erase(p.first, p.second);
1.467 +
1.468 + for (arc_list_t::iterator merge = map_add_queue.begin();
1.469 + merge != map_add_queue.end();
1.470 + map_add_queue.erase(merge++)) {
1.471 + to_map.insert(arc_map_t::value_type((*merge)->m_to, *merge));
1.472 + }
1.473 +
1.474 + // Now, roll anything that arc->m_to used to point at into
1.475 + // what arc->m_from now points at.
1.476 +
1.477 + // Collect all of the arcs that originate at arc->m_to.
1.478 + p = from_map.equal_range(arc->m_to);
1.479 + for (arc_map_t::iterator i = p.first; i != p.second; ++i) {
1.480 + // Remove the arc originating from arc->m_to (`doomed')
1.481 + // from all of our indicies.
1.482 + call_graph_arc *doomed = i->second;
1.483 + const Elf32_Sym *sink = doomed->m_to;
1.484 +
1.485 + // There shouldn't be any self-referential arcs.
1.486 + assert(sink != arc->m_to);
1.487 +
1.488 + sorted_arcs.erase(doomed);
1.489 + arcs.erase(doomed);
1.490 + remove_from(to_map, sink, doomed);
1.491 + // N.B. that `doomed' will be removed from the `from_map'
1.492 + // once the loop completes.
1.493 +
1.494 + // Create a new (or locate an existing) arc whose source
1.495 + // is arc->m_from and whose sink was the removed arc's
1.496 + // sink.
1.497 + call_graph_arc *merge;
1.498 + call_graph_arc key = call_graph_arc(arc->m_from, sink);
1.499 + arc_container_t::iterator iter = arcs.find(&key);
1.500 +
1.501 + if (iter == arcs.end()) {
1.502 + merge = new call_graph_arc(arc->m_from, sink);
1.503 +
1.504 + arcs.insert(merge);
1.505 +
1.506 + map_add_queue.push_back(merge);
1.507 + to_map.insert(arc_map_t::value_type(merge->m_to, merge));
1.508 + }
1.509 + else {
1.510 + // We found an existing arc: temporarily remove it
1.511 + // from the sorted index.
1.512 + merge = const_cast<call_graph_arc *>(*iter);
1.513 + sorted_arcs.erase(merge);
1.514 + }
1.515 +
1.516 + // Include the doomed arc's weight in the merged arc, and
1.517 + // (re-)insert it into the sorted index.
1.518 + merge->m_count += doomed->m_count;
1.519 + sorted_arcs.insert(merge);
1.520 +
1.521 + delete doomed;
1.522 + }
1.523 +
1.524 + from_map.erase(p.first, p.second);
1.525 +
1.526 + for (arc_list_t::iterator merge = map_add_queue.begin();
1.527 + merge != map_add_queue.end();
1.528 + map_add_queue.erase(merge++)) {
1.529 + from_map.insert(arc_map_t::value_type((*merge)->m_from, *merge));
1.530 + }
1.531 + }
1.532 +
1.533 + out.close();
1.534 + return 0;
1.535 +}
