diff -r 000000000000 -r 6474c204b198 tools/reorder/grope.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/reorder/grope.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,532 @@
+/* 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;
+}