The Tor Browser: comparison tools/reorder/grope.cpp

--1:000000000000
+:7eae0c15a721
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/*
+A program that computes a function ordering for an executable based
+on runtime profile information.
+This program is directly based on work done by Roger Chickering
+<rogc@netscape.com> in
+<http://bugzilla.mozilla.org/show_bug.cgi?id=65845>
+to implement Nat Friedman's <nat@nat.org> `grope',
+_GNU Rope - A Subroutine Position Optimizer_
+<http://www.hungry.com/~shaver/grope/grope.ps>
+Specifically, it implements the procedure re-ordering algorithm
+described in:
+K. Pettis and R. Hansen. ``Profile-Guided Core Position.'' In
+_Proceedings of the Int. Conference on Programming Language Design
+and Implementation_, pages 16-27, June 1990.
+*/
+#include <assert.h>
+#include <fstream>
+#include <hash_set>
+#include <map>
+#include <set>
+#include <list>
+#include <vector>
+#include <limits.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include "elf_symbol_table.h"
+#define _GNU_SOURCE
+#include <getopt.h>
+elf_symbol_table symtab;
+// Straight outta plhash.c!
+#define GOLDEN_RATIO 0x9E3779B9U
+struct hash<const Elf32_Sym *>
+{
+size_t operator()(const Elf32_Sym *sym) const {
+return (reinterpret_cast<size_t>(sym) >> 4) * GOLDEN_RATIO; }
+};
+typedef unsigned int call_count_t;
+struct call_graph_arc
+{
+const Elf32_Sym *m_from;
+const Elf32_Sym *m_to;
+call_count_t     m_count;
+call_graph_arc(const Elf32_Sym *left, const Elf32_Sym *right, call_count_t count = 0)
+: m_count(count)
+{
+assert(left != right);
+if (left > right) {
+m_from = left;
+m_to   = right;
+}
+else {
+m_from = right;
+m_to   = left;
+}
+}
+friend bool
+operator==(const call_graph_arc &lhs, const call_graph_arc &rhs)
+{
+return (lhs.m_from == rhs.m_from) && (lhs.m_to == rhs.m_to);
+}
+friend ostream &
+operator<<(ostream &out, const call_graph_arc &arc)
+{
+out << &arc << ": ";
+out.form("<(%s %s) %d>",
+symtab.get_symbol_name(arc.m_from),
+symtab.get_symbol_name(arc.m_to),
+arc.m_count);
+return out;
+}
+};
+struct hash<call_graph_arc *>
+{
+size_t
+operator()(const call_graph_arc* arc) const
+{
+size_t result;
+result = reinterpret_cast<unsigned long>(arc->m_from);
+result ^= reinterpret_cast<unsigned long>(arc->m_to) >> 16;
+result ^= reinterpret_cast<unsigned long>(arc->m_to) << 16;
+result *= GOLDEN_RATIO;
+return result;
+}
+};
+struct equal_to<call_graph_arc *>
+{
+bool
+operator()(const call_graph_arc* lhs, const call_graph_arc *rhs) const
+{
+return *lhs == *rhs;
+}
+};
+typedef hash_set<call_graph_arc *> arc_container_t;
+arc_container_t arcs;
+typedef multimap<const Elf32_Sym *, call_graph_arc *> arc_map_t;
+arc_map_t from_map;
+arc_map_t to_map;
+struct less_call_graph_arc_count
+{
+bool
+operator()(const call_graph_arc *lhs, const call_graph_arc *rhs) const
+{
+if (lhs->m_count == rhs->m_count) {
+if (lhs->m_from == rhs->m_from)
+return lhs->m_to > rhs->m_to;
+return lhs->m_from > rhs->m_from;
+}
+return lhs->m_count > rhs->m_count;
+}
+};
+typedef set<call_graph_arc *, less_call_graph_arc_count> arc_count_index_t;
+bool opt_debug = false;
+const char *opt_out = "order.out";
+int opt_tick = 0;
+bool opt_verbose = false;
+int opt_window = 16;
+static struct option long_options[] = {
+{ "debug",       no_argument,       0, 'd' },
+{ "exe",         required_argument, 0, 'e' },
+{ "help",        no_argument,       0, '?' },
+{ "out",         required_argument, 0, 'o' },
+{ "tick",        optional_argument, 0, 't' },
+{ "verbose",     no_argument,       0, 'v' },
+{ "window",      required_argument, 0, 'w' },
+{ 0,             0,                 0, 0   }
+};
+//----------------------------------------------------------------------
+static void
+usage(const char *name)
+{
+cerr << "usage: " << name << " [options] [<file> ...]" << endl;
+cerr << "  Options:" << endl;
+cerr << "  --debug, -d" << endl;
+cerr << "      Print lots of verbose debugging cruft." << endl;
+cerr << "  --exe=<image>, -e <image> (required)" << endl;
+cerr << "      Specify the executable image from which to read symbol information." << endl;
+cerr << "  --help, -?" << endl;
+cerr << "      Print this message and exit." << endl;
+cerr << "  --out=<file>, -o <file>" << endl;
+cerr << "      Specify the output file to which to dump the symbol ordering of the" << endl;
+cerr << "      best individual (default is `order.out')." << endl;
+cerr << "  --tick[=<num>], -t [<num>]" << endl;
+cerr << "      When reading address data, print a dot to stderr every <num>th" << endl;
+cerr << "      address processed from the call trace. If specified with no argument," << endl;
+cerr << "      a dot will be printed for every million addresses processed." << endl;
+cerr << "  --verbose, -v" << endl;
+cerr << "      Issue progress messages to stderr." << endl;
+cerr << "  --window=<num>, -w <num>" << endl;
+cerr << "      Use a sliding window instead of pagination to score orderings." << endl;
+}
+/**
+* Using the symbol table, map a stream of address references into a
+* callgraph.
+*/
+static void
+map_addrs(int fd)
+{
+long long total_calls = 0;
+typedef list<const Elf32_Sym *> window_t;
+window_t window;
+int window_size = 0;
+unsigned int buf[128];
+ssize_t cb;
+while ((cb = read(fd, buf, sizeof buf)) > 0) {
+if (cb % sizeof buf[0])
+fprintf(stderr, "unaligned read\n");
+unsigned int *addr = buf;
+unsigned int *limit = buf + (cb / 4);
+for (; addr < limit; ++addr) {
+const Elf32_Sym *sym = symtab.lookup(*addr);
+if (! sym)
+continue;
+++total_calls;
+window.push_front(sym);
+if (window_size >= opt_window)
+window.pop_back();
+else
+++window_size;
+window_t::const_iterator i = window.begin();
+window_t::const_iterator end = window.end();
+for (; i != end; ++i) {
+if (sym != *i) {
+call_graph_arc *arc;
+call_graph_arc key(sym, *i);
+arc_container_t::iterator iter = arcs.find(&key);
+if (iter == arcs.end()) {
+arc = new call_graph_arc(sym, *i);
+arcs.insert(arc);
+from_map.insert(arc_map_t::value_type(arc->m_from, arc));
+to_map.insert(arc_map_t::value_type(arc->m_to, arc));
+}
+else
+arc = const_cast<call_graph_arc *>(*iter);
+++(arc->m_count);
+}
+}
+if (opt_verbose && opt_tick && (total_calls % opt_tick == 0)) {
+cerr << ".";
+flush(cerr);
+}
+}
+}
+if (opt_verbose) {
+if (opt_tick)
+cerr << endl;
+cerr << "Total calls: " << total_calls << endl;
+}
+}
+static void
+remove_from(arc_map_t& map, const Elf32_Sym *sym, const call_graph_arc *arc)
+{
+pair<arc_map_t::iterator, arc_map_t::iterator> p
+= map.equal_range(sym);
+for (arc_map_t::iterator i = p.first; i != p.second; ++i) {
+if (i->second == arc) {
+map.erase(i);
+break;
+}
+}
+}
+/**
+* The main program
+*/
+int
+main(int argc, char *argv[])
+{
+const char *opt_exe = 0;
+int c;
+while (1) {
+int option_index = 0;
+c = getopt_long(argc, argv, "?de:o:t:vw:", long_options, &option_index);
+if (c < 0)
+break;
+switch (c) {
+case '?':
+usage(argv[0]);
+return 0;
+case 'd':
+opt_debug = true;
+break;
+case 'e':
+opt_exe = optarg;
+break;
+case 'o':
+opt_out = optarg;
+break;
+case 't':
+opt_tick = optarg ? atoi(optarg) : 1000000;
+break;
+case 'v':
+opt_verbose = true;
+break;
+case 'w':
+opt_window = atoi(optarg);
+if (opt_window <= 0) {
+cerr << "invalid window size: " << opt_window << endl;
+return 1;
+}
+break;
+default:
+usage(argv[0]);
+return 1;
+}
+}
+// Make sure an image was specified
+if (! opt_exe) {
+usage(argv[0]);
+return 1;
+}
+// Read the sym table.
+symtab.init(opt_exe);
+// Process addresses to construct the weighted call graph.
+if (optind >= argc) {
+map_addrs(STDIN_FILENO);
+}
+else {
+do {
+int fd = open(argv[optind], O_RDONLY);
+if (fd < 0) {
+perror(argv[optind]);
+return 1;
+}
+map_addrs(fd);
+close(fd);
+} while (++optind < argc);
+}
+// Emit the ordering.
+ofstream out(opt_out);
+// Collect all of the arcs into a sorted container, with arcs
+// having the largest weight at the front.
+arc_count_index_t sorted_arcs(arcs.begin(), arcs.end());
+while (sorted_arcs.size()) {
+if (opt_debug) {
+cerr << "==========================================" << endl << endl;
+cerr << "Sorted Arcs:" << endl;
+for (arc_count_index_t::const_iterator iter = sorted_arcs.begin();
+iter != sorted_arcs.end();
+++iter) {
+cerr << **iter << endl;
+}
+cerr << endl << "Arc Container:" << endl;
+for (arc_container_t::const_iterator iter = arcs.begin();
+iter != arcs.end();
+++iter) {
+cerr << **iter << endl;
+}
+cerr << endl << "From Map:" << endl;
+for (arc_map_t::const_iterator iter = from_map.begin();
+iter != from_map.end();
+++iter) {
+cerr << symtab.get_symbol_name(iter->first) << ": " << *(iter->second) << endl;
+}
+cerr << endl << "To Map:" << endl;
+for (arc_map_t::const_iterator iter = to_map.begin();
+iter != to_map.end();
+++iter) {
+cerr << symtab.get_symbol_name(iter->first) << ": " << *(iter->second) << endl;
+}
+cerr << endl;
+}
+// The first arc in the sorted set will have the largest
+// weight. Pull it out, and emit its sink.
+arc_count_index_t::iterator max = sorted_arcs.begin();
+call_graph_arc *arc = const_cast<call_graph_arc *>(*max);
+sorted_arcs.erase(max);
+if (opt_debug)
+cerr << "pulling " << *arc << endl;
+arcs.erase(arc);
+remove_from(from_map, arc->m_from, arc);
+remove_from(to_map, arc->m_to, arc);
+out << symtab.get_symbol_name(arc->m_to) << endl;
+// Merge arc->m_to into arc->m_from. First, modify anything
+// that used to point to arc->m_to to point to arc->m_from.
+typedef list<call_graph_arc *> arc_list_t;
+arc_list_t map_add_queue;
+pair<arc_map_t::iterator, arc_map_t::iterator> p;
+// Find all the arcs that point to arc->m_to.
+p = to_map.equal_range(arc->m_to);
+for (arc_map_t::iterator i = p.first; i != p.second; ++i) {
+// Remove the arc that points to arc->m_to (`doomed') from
+// all of our indicies.
+call_graph_arc *doomed = i->second;
+const Elf32_Sym *source = doomed->m_from;
+sorted_arcs.erase(doomed);
+arcs.erase(doomed);
+remove_from(from_map, source, doomed);
+// N.B. that `doomed' will be removed from the `to_map'
+// after the loop completes.
+// Create a new (or locate an existing) arc whose source
+// was the doomed arc's source, and whose sink is
+// arc->m_from (i.e., the node that subsumed arc->m_to).
+call_graph_arc *merge;
+call_graph_arc key = call_graph_arc(source, arc->m_from);
+arc_container_t::iterator iter = arcs.find(&key);
+if (iter == arcs.end()) {
+merge = new call_graph_arc(source, arc->m_from);
+arcs.insert(merge);
+from_map.insert(arc_map_t::value_type(merge->m_from, merge));
+map_add_queue.push_back(merge);
+}
+else {
+// We found an existing arc: temporarily remove it
+// from the sorted index.
+merge = const_cast<call_graph_arc *>(*iter);
+sorted_arcs.erase(merge);
+}
+// Include the doomed arc's weight in the merged arc, and
+// (re-)insert it into the sorted index.
+merge->m_count += doomed->m_count;
+sorted_arcs.insert(merge);
+delete doomed;
+}
+to_map.erase(p.first, p.second);
+for (arc_list_t::iterator merge = map_add_queue.begin();
+merge != map_add_queue.end();
+map_add_queue.erase(merge++)) {
+to_map.insert(arc_map_t::value_type((*merge)->m_to, *merge));
+}
+// Now, roll anything that arc->m_to used to point at into
+// what arc->m_from now points at.
+// Collect all of the arcs that originate at arc->m_to.
+p = from_map.equal_range(arc->m_to);
+for (arc_map_t::iterator i = p.first; i != p.second; ++i) {
+// Remove the arc originating from arc->m_to (`doomed')
+// from all of our indicies.
+call_graph_arc *doomed = i->second;
+const Elf32_Sym *sink = doomed->m_to;
+// There shouldn't be any self-referential arcs.
+assert(sink != arc->m_to);
+sorted_arcs.erase(doomed);
+arcs.erase(doomed);
+remove_from(to_map, sink, doomed);
+// N.B. that `doomed' will be removed from the `from_map'
+// once the loop completes.
+// Create a new (or locate an existing) arc whose source
+// is arc->m_from and whose sink was the removed arc's
+// sink.
+call_graph_arc *merge;
+call_graph_arc key = call_graph_arc(arc->m_from, sink);
+arc_container_t::iterator iter = arcs.find(&key);
+if (iter == arcs.end()) {
+merge = new call_graph_arc(arc->m_from, sink);
+arcs.insert(merge);
+map_add_queue.push_back(merge);
+to_map.insert(arc_map_t::value_type(merge->m_to, merge));
+}
+else {
+// We found an existing arc: temporarily remove it
+// from the sorted index.
+merge = const_cast<call_graph_arc *>(*iter);
+sorted_arcs.erase(merge);
+}
+// Include the doomed arc's weight in the merged arc, and
+// (re-)insert it into the sorted index.
+merge->m_count += doomed->m_count;
+sorted_arcs.insert(merge);
+delete doomed;
+}
+from_map.erase(p.first, p.second);
+for (arc_list_t::iterator merge = map_add_queue.begin();
+merge != map_add_queue.end();
+map_add_queue.erase(merge++)) {
+from_map.insert(arc_map_t::value_type((*merge)->m_from, *merge));
+}
+}
+out.close();
+return 0;
+}

The Tor Browser / file comparison

comparison: tools/reorder/grope.cpp

tools/reorder/grope.cpp