Between Tuesday August 20th, 5:00pm and Thursday August 22nd, 8:00am git.uwaterloo.ca will be down for an upgrade to version 10.8.7.

SConstruct 55.2 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436
# -*- mode:python -*-

# Copyright (c) 2013, 2015 ARM Limited
# All rights reserved.
#
# The license below extends only to copyright in the software and shall
# not be construed as granting a license to any other intellectual
# property including but not limited to intellectual property relating
# to a hardware implementation of the functionality of the software
# licensed hereunder.  You may use the software subject to the license
# terms below provided that you ensure that this notice is replicated
# unmodified and in its entirety in all distributions of the software,
# modified or unmodified, in source code or in binary form.
#
# Copyright (c) 2011 Advanced Micro Devices, Inc.
# Copyright (c) 2009 The Hewlett-Packard Development Company
# Copyright (c) 2004-2005 The Regents of The University of Michigan
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Authors: Steve Reinhardt
#          Nathan Binkert

###################################################
#
# SCons top-level build description (SConstruct) file.
#
# While in this directory ('gem5'), just type 'scons' to build the default
# configuration (see below), or type 'scons build/<CONFIG>/<binary>'
# to build some other configuration (e.g., 'build/ALPHA/gem5.opt' for
# the optimized full-system version).
#
# You can build gem5 in a different directory as long as there is a
# 'build/<CONFIG>' somewhere along the target path.  The build system
# expects that all configs under the same build directory are being
# built for the same host system.
#
# Examples:
#
#   The following two commands are equivalent.  The '-u' option tells
#   scons to search up the directory tree for this SConstruct file.
#   % cd <path-to-src>/gem5 ; scons build/ALPHA/gem5.debug
#   % cd <path-to-src>/gem5/build/ALPHA; scons -u gem5.debug
#
#   The following two commands are equivalent and demonstrate building
#   in a directory outside of the source tree.  The '-C' option tells
#   scons to chdir to the specified directory to find this SConstruct
#   file.
#   % cd <path-to-src>/gem5 ; scons /local/foo/build/ALPHA/gem5.debug
#   % cd /local/foo/build/ALPHA; scons -C <path-to-src>/gem5 gem5.debug
#
# You can use 'scons -H' to print scons options.  If you're in this
# 'gem5' directory (or use -u or -C to tell scons where to find this
# file), you can use 'scons -h' to print all the gem5-specific build
# options as well.
#
###################################################

# Check for recent-enough Python and SCons versions.
try:
    # Really old versions of scons only take two options for the
    # function, so check once without the revision and once with the
    # revision, the first instance will fail for stuff other than
    # 0.98, and the second will fail for 0.98.0
    EnsureSConsVersion(0, 98)
    EnsureSConsVersion(0, 98, 1)
except SystemExit, e:
    print """
For more details, see:
    http://gem5.org/Dependencies
"""
    raise

# We ensure the python version early because because python-config
# requires python 2.5
try:
    EnsurePythonVersion(2, 5)
except SystemExit, e:
    print """
You can use a non-default installation of the Python interpreter by
rearranging your PATH so that scons finds the non-default 'python' and
'python-config' first.

For more details, see:
    http://gem5.org/wiki/index.php/Using_a_non-default_Python_installation
"""
    raise

# Global Python includes
import itertools
import os
import re
import subprocess
import sys

from os import mkdir, environ
from os.path import abspath, basename, dirname, expanduser, normpath
from os.path import exists,  isdir, isfile
from os.path import join as joinpath, split as splitpath

# SCons includes
import SCons
import SCons.Node

extra_python_paths = [
    Dir('src/python').srcnode().abspath, # gem5 includes
    Dir('ext/ply').srcnode().abspath, # ply is used by several files
    ]

sys.path[1:1] = extra_python_paths

from m5.util import compareVersions, readCommand
from m5.util.terminal import get_termcap

help_texts = {
    "options" : "",
    "global_vars" : "",
    "local_vars" : ""
}

Export("help_texts")


# There's a bug in scons in that (1) by default, the help texts from
# AddOption() are supposed to be displayed when you type 'scons -h'
# and (2) you can override the help displayed by 'scons -h' using the
# Help() function, but these two features are incompatible: once
# you've overridden the help text using Help(), there's no way to get
# at the help texts from AddOptions.  See:
#     http://scons.tigris.org/issues/show_bug.cgi?id=2356
#     http://scons.tigris.org/issues/show_bug.cgi?id=2611
# This hack lets us extract the help text from AddOptions and
# re-inject it via Help().  Ideally someday this bug will be fixed and
# we can just use AddOption directly.
def AddLocalOption(*args, **kwargs):
    col_width = 30

    help = "  " + ", ".join(args)
    if "help" in kwargs:
        length = len(help)
        if length >= col_width:
            help += "\n" + " " * col_width
        else:
            help += " " * (col_width - length)
        help += kwargs["help"]
    help_texts["options"] += help + "\n"

    AddOption(*args, **kwargs)

AddLocalOption('--colors', dest='use_colors', action='store_true',
               help="Add color to abbreviated scons output")
AddLocalOption('--no-colors', dest='use_colors', action='store_false',
               help="Don't add color to abbreviated scons output")
AddLocalOption('--with-cxx-config', dest='with_cxx_config',
               action='store_true',
               help="Build with support for C++-based configuration")
AddLocalOption('--default', dest='default', type='string', action='store',
               help='Override which build_opts file to use for defaults')
AddLocalOption('--ignore-style', dest='ignore_style', action='store_true',
               help='Disable style checking hooks')
AddLocalOption('--no-lto', dest='no_lto', action='store_true',
               help='Disable Link-Time Optimization for fast')
AddLocalOption('--update-ref', dest='update_ref', action='store_true',
               help='Update test reference outputs')
AddLocalOption('--verbose', dest='verbose', action='store_true',
               help='Print full tool command lines')
AddLocalOption('--without-python', dest='without_python',
               action='store_true',
               help='Build without Python configuration support')
AddLocalOption('--without-tcmalloc', dest='without_tcmalloc',
               action='store_true',
               help='Disable linking against tcmalloc')
AddLocalOption('--with-ubsan', dest='with_ubsan', action='store_true',
               help='Build with Undefined Behavior Sanitizer if available')

termcap = get_termcap(GetOption('use_colors'))

########################################################################
#
# Set up the main build environment.
#
########################################################################

# export TERM so that clang reports errors in color
use_vars = set([ 'AS', 'AR', 'CC', 'CXX', 'HOME', 'LD_LIBRARY_PATH',
                 'LIBRARY_PATH', 'PATH', 'PKG_CONFIG_PATH', 'PROTOC',
                 'PYTHONPATH', 'RANLIB', 'SWIG', 'TERM' ])

use_prefixes = [
    "M5",           # M5 configuration (e.g., path to kernels)
    "DISTCC_",      # distcc (distributed compiler wrapper) configuration
    "CCACHE_",      # ccache (caching compiler wrapper) configuration
    "CCC_",         # clang static analyzer configuration
    ]

use_env = {}
for key,val in sorted(os.environ.iteritems()):
    if key in use_vars or \
            any([key.startswith(prefix) for prefix in use_prefixes]):
        use_env[key] = val

# Tell scons to avoid implicit command dependencies to avoid issues
# with the param wrappes being compiled twice (see
# http://scons.tigris.org/issues/show_bug.cgi?id=2811)
main = Environment(ENV=use_env, IMPLICIT_COMMAND_DEPENDENCIES=0)
main.Decider('MD5-timestamp')
main.root = Dir(".")         # The current directory (where this file lives).
main.srcdir = Dir("src")     # The source directory

main_dict_keys = main.Dictionary().keys()

# Check that we have a C/C++ compiler
if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
    print "No C++ compiler installed (package g++ on Ubuntu and RedHat)"
    Exit(1)

# Check that swig is present
if not 'SWIG' in main_dict_keys:
    print "swig is not installed (package swig on Ubuntu and RedHat)"
    Exit(1)

# add useful python code PYTHONPATH so it can be used by subprocesses
# as well
main.AppendENVPath('PYTHONPATH', extra_python_paths)

########################################################################
#
# Mercurial Stuff.
#
# If the gem5 directory is a mercurial repository, we should do some
# extra things.
#
########################################################################

hgdir = main.root.Dir(".hg")

mercurial_style_message = """
You're missing the gem5 style hook, which automatically checks your code
against the gem5 style rules on hg commit and qrefresh commands.  This
script will now install the hook in your .hg/hgrc file.
Press enter to continue, or ctrl-c to abort: """

mercurial_style_hook = """
# The following lines were automatically added by gem5/SConstruct
# to provide the gem5 style-checking hooks
[extensions]
style = %s/util/style.py

[hooks]
pretxncommit.style = python:style.check_style
pre-qrefresh.style = python:style.check_style
# End of SConstruct additions

""" % (main.root.abspath)

mercurial_lib_not_found = """
Mercurial libraries cannot be found, ignoring style hook.  If
you are a gem5 developer, please fix this and run the style
hook. It is important.
"""

# Check for style hook and prompt for installation if it's not there.
# Skip this if --ignore-style was specified, there's no .hg dir to
# install a hook in, or there's no interactive terminal to prompt.
if not GetOption('ignore_style') and hgdir.exists() and sys.stdin.isatty():
    style_hook = True
    try:
        from mercurial import ui
        ui = ui.ui()
        ui.readconfig(hgdir.File('hgrc').abspath)
        style_hook = ui.config('hooks', 'pretxncommit.style', None) and \
                     ui.config('hooks', 'pre-qrefresh.style', None)
    except ImportError:
        print mercurial_lib_not_found

    if not style_hook:
        print mercurial_style_message,
        # continue unless user does ctrl-c/ctrl-d etc.
        try:
            raw_input()
        except:
            print "Input exception, exiting scons.\n"
            sys.exit(1)
        hgrc_path = '%s/.hg/hgrc' % main.root.abspath
        print "Adding style hook to", hgrc_path, "\n"
        try:
            hgrc = open(hgrc_path, 'a')
            hgrc.write(mercurial_style_hook)
            hgrc.close()
        except:
            print "Error updating", hgrc_path
            sys.exit(1)


###################################################
#
# Figure out which configurations to set up based on the path(s) of
# the target(s).
#
###################################################

# Find default configuration & binary.
Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))

# helper function: find last occurrence of element in list
def rfind(l, elt, offs = -1):
    for i in range(len(l)+offs, 0, -1):
        if l[i] == elt:
            return i
    raise ValueError, "element not found"

# Take a list of paths (or SCons Nodes) and return a list with all
# paths made absolute and ~-expanded.  Paths will be interpreted
# relative to the launch directory unless a different root is provided
def makePathListAbsolute(path_list, root=GetLaunchDir()):
    return [abspath(joinpath(root, expanduser(str(p))))
            for p in path_list]

# Each target must have 'build' in the interior of the path; the
# directory below this will determine the build parameters.  For
# example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
# recognize that ALPHA_SE specifies the configuration because it
# follow 'build' in the build path.

# The funky assignment to "[:]" is needed to replace the list contents
# in place rather than reassign the symbol to a new list, which
# doesn't work (obviously!).
BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)

# Generate a list of the unique build roots and configs that the
# collected targets reference.
variant_paths = []
build_root = None
for t in BUILD_TARGETS:
    path_dirs = t.split('/')
    try:
        build_top = rfind(path_dirs, 'build', -2)
    except:
        print "Error: no non-leaf 'build' dir found on target path", t
        Exit(1)
    this_build_root = joinpath('/',*path_dirs[:build_top+1])
    if not build_root:
        build_root = this_build_root
    else:
        if this_build_root != build_root:
            print "Error: build targets not under same build root\n"\
                  "  %s\n  %s" % (build_root, this_build_root)
            Exit(1)
    variant_path = joinpath('/',*path_dirs[:build_top+2])
    if variant_path not in variant_paths:
        variant_paths.append(variant_path)

# Make sure build_root exists (might not if this is the first build there)
if not isdir(build_root):
    mkdir(build_root)
main['BUILDROOT'] = build_root

Export('main')

main.SConsignFile(joinpath(build_root, "sconsign"))

# Default duplicate option is to use hard links, but this messes up
# when you use emacs to edit a file in the target dir, as emacs moves
# file to file~ then copies to file, breaking the link.  Symbolic
# (soft) links work better.
main.SetOption('duplicate', 'soft-copy')

#
# Set up global sticky variables... these are common to an entire build
# tree (not specific to a particular build like ALPHA_SE)
#

global_vars_file = joinpath(build_root, 'variables.global')

global_vars = Variables(global_vars_file, args=ARGUMENTS)

global_vars.AddVariables(
    ('CC', 'C compiler', environ.get('CC', main['CC'])),
    ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
    ('SWIG', 'SWIG tool', environ.get('SWIG', main['SWIG'])),
    ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
    ('BATCH', 'Use batch pool for build and tests', False),
    ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
    ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
    ('EXTRAS', 'Add extra directories to the compilation', '')
    )

# Update main environment with values from ARGUMENTS & global_vars_file
global_vars.Update(main)
help_texts["global_vars"] += global_vars.GenerateHelpText(main)

# Save sticky variable settings back to current variables file
global_vars.Save(global_vars_file, main)

# Parse EXTRAS variable to build list of all directories where we're
# look for sources etc.  This list is exported as extras_dir_list.
base_dir = main.srcdir.abspath
if main['EXTRAS']:
    extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
else:
    extras_dir_list = []

Export('base_dir')
Export('extras_dir_list')

# the ext directory should be on the #includes path
main.Append(CPPPATH=[Dir('ext')])

def strip_build_path(path, env):
    path = str(path)
    variant_base = env['BUILDROOT'] + os.path.sep
    if path.startswith(variant_base):
        path = path[len(variant_base):]
    elif path.startswith('build/'):
        path = path[6:]
    return path

# Generate a string of the form:
#   common/path/prefix/src1, src2 -> tgt1, tgt2
# to print while building.
class Transform(object):
    # all specific color settings should be here and nowhere else
    tool_color = termcap.Normal
    pfx_color = termcap.Yellow
    srcs_color = termcap.Yellow + termcap.Bold
    arrow_color = termcap.Blue + termcap.Bold
    tgts_color = termcap.Yellow + termcap.Bold

    def __init__(self, tool, max_sources=99):
        self.format = self.tool_color + (" [%8s] " % tool) \
                      + self.pfx_color + "%s" \
                      + self.srcs_color + "%s" \
                      + self.arrow_color + " -> " \
                      + self.tgts_color + "%s" \
                      + termcap.Normal
        self.max_sources = max_sources

    def __call__(self, target, source, env, for_signature=None):
        # truncate source list according to max_sources param
        source = source[0:self.max_sources]
        def strip(f):
            return strip_build_path(str(f), env)
        if len(source) > 0:
            srcs = map(strip, source)
        else:
            srcs = ['']
        tgts = map(strip, target)
        # surprisingly, os.path.commonprefix is a dumb char-by-char string
        # operation that has nothing to do with paths.
        com_pfx = os.path.commonprefix(srcs + tgts)
        com_pfx_len = len(com_pfx)
        if com_pfx:
            # do some cleanup and sanity checking on common prefix
            if com_pfx[-1] == ".":
                # prefix matches all but file extension: ok
                # back up one to change 'foo.cc -> o' to 'foo.cc -> .o'
                com_pfx = com_pfx[0:-1]
            elif com_pfx[-1] == "/":
                # common prefix is directory path: OK
                pass
            else:
                src0_len = len(srcs[0])
                tgt0_len = len(tgts[0])
                if src0_len == com_pfx_len:
                    # source is a substring of target, OK
                    pass
                elif tgt0_len == com_pfx_len:
                    # target is a substring of source, need to back up to
                    # avoid empty string on RHS of arrow
                    sep_idx = com_pfx.rfind(".")
                    if sep_idx != -1:
                        com_pfx = com_pfx[0:sep_idx]
                    else:
                        com_pfx = ''
                elif src0_len > com_pfx_len and srcs[0][com_pfx_len] == ".":
                    # still splitting at file extension: ok
                    pass
                else:
                    # probably a fluke; ignore it
                    com_pfx = ''
        # recalculate length in case com_pfx was modified
        com_pfx_len = len(com_pfx)
        def fmt(files):
            f = map(lambda s: s[com_pfx_len:], files)
            return ', '.join(f)
        return self.format % (com_pfx, fmt(srcs), fmt(tgts))

Export('Transform')

# enable the regression script to use the termcap
main['TERMCAP'] = termcap

if GetOption('verbose'):
    def MakeAction(action, string, *args, **kwargs):
        return Action(action, *args, **kwargs)
else:
    MakeAction = Action
    main['CCCOMSTR']        = Transform("CC")
    main['CXXCOMSTR']       = Transform("CXX")
    main['ASCOMSTR']        = Transform("AS")
    main['SWIGCOMSTR']      = Transform("SWIG")
    main['ARCOMSTR']        = Transform("AR", 0)
    main['LINKCOMSTR']      = Transform("LINK", 0)
    main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
    main['M4COMSTR']        = Transform("M4")
    main['SHCCCOMSTR']      = Transform("SHCC")
    main['SHCXXCOMSTR']     = Transform("SHCXX")
Export('MakeAction')

# Initialize the Link-Time Optimization (LTO) flags
main['LTO_CCFLAGS'] = []
main['LTO_LDFLAGS'] = []

# According to the readme, tcmalloc works best if the compiler doesn't
# assume that we're using the builtin malloc and friends. These flags
# are compiler-specific, so we need to set them after we detect which
# compiler we're using.
main['TCMALLOC_CCFLAGS'] = []

CXX_version = readCommand([main['CXX'],'--version'], exception=False)
CXX_V = readCommand([main['CXX'],'-V'], exception=False)

main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
if main['GCC'] + main['CLANG'] > 1:
    print 'Error: How can we have two at the same time?'
    Exit(1)

# Set up default C++ compiler flags
if main['GCC'] or main['CLANG']:
    # As gcc and clang share many flags, do the common parts here
    main.Append(CCFLAGS=['-pipe'])
    main.Append(CCFLAGS=['-fno-strict-aliasing'])
    # Enable -Wall and then disable the few warnings that we
    # consistently violate
    main.Append(CCFLAGS=['-Wall', '-Wno-sign-compare', '-Wundef'])
    # We always compile using C++11, but only gcc >= 4.7 and clang 3.1
    # actually use that name, so we stick with c++0x
    main.Append(CXXFLAGS=['-std=c++0x'])
    # Add selected sanity checks from -Wextra
    main.Append(CXXFLAGS=['-Wmissing-field-initializers',
                          '-Woverloaded-virtual'])
else:
    print termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal,
    print "Don't know what compiler options to use for your compiler."
    print termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX']
    print termcap.Yellow + '       version:' + termcap.Normal,
    if not CXX_version:
        print termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +\
               termcap.Normal
    else:
        print CXX_version.replace('\n', '<nl>')
    print "       If you're trying to use a compiler other than GCC"
    print "       or clang, there appears to be something wrong with your"
    print "       environment."
    print "       "
    print "       If you are trying to use a compiler other than those listed"
    print "       above you will need to ease fix SConstruct and "
    print "       src/SConscript to support that compiler."
    Exit(1)

if main['GCC']:
    # Check for a supported version of gcc. >= 4.6 is chosen for its
    # level of c++11 support. See
    # http://gcc.gnu.org/projects/cxx0x.html for details. 4.6 is also
    # the first version with proper LTO support.
    gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
    if compareVersions(gcc_version, "4.6") < 0:
        print 'Error: gcc version 4.6 or newer required.'
        print '       Installed version:', gcc_version
        Exit(1)

    main['GCC_VERSION'] = gcc_version

    # gcc from version 4.8 and above generates "rep; ret" instructions
    # to avoid performance penalties on certain AMD chips. Older
    # assemblers detect this as an error, "Error: expecting string
    # instruction after `rep'"
    if compareVersions(gcc_version, "4.8") > 0:
        as_version_raw = readCommand([main['AS'], '-v', '/dev/null'],
                                     exception=False).split()

        # version strings may contain extra distro-specific
        # qualifiers, so play it safe and keep only what comes before
        # the first hyphen
        as_version = as_version_raw[-1].split('-')[0] if as_version_raw \
            else None

        if not as_version or compareVersions(as_version, "2.23") < 0:
            print termcap.Yellow + termcap.Bold + \
                'Warning: This combination of gcc and binutils have' + \
                ' known incompatibilities.\n' + \
                '         If you encounter build problems, please update ' + \
                'binutils to 2.23.' + \
                termcap.Normal

    # Make sure we warn if the user has requested to compile with the
    # Undefined Benahvior Sanitizer and this version of gcc does not
    # support it.
    if GetOption('with_ubsan') and \
            compareVersions(gcc_version, '4.9') < 0:
        print termcap.Yellow + termcap.Bold + \
            'Warning: UBSan is only supported using gcc 4.9 and later.' + \
            termcap.Normal

    # Add the appropriate Link-Time Optimization (LTO) flags
    # unless LTO is explicitly turned off. Note that these flags
    # are only used by the fast target.
    if not GetOption('no_lto'):
        # Pass the LTO flag when compiling to produce GIMPLE
        # output, we merely create the flags here and only append
        # them later
        main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]

        # Use the same amount of jobs for LTO as we are running
        # scons with
        main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]

    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
                                  '-fno-builtin-realloc', '-fno-builtin-free'])

elif main['CLANG']:
    # Check for a supported version of clang, >= 3.0 is needed to
    # support similar features as gcc 4.6. See
    # http://clang.llvm.org/cxx_status.html for details
    clang_version_re = re.compile(".* version (\d+\.\d+)")
    clang_version_match = clang_version_re.search(CXX_version)
    if (clang_version_match):
        clang_version = clang_version_match.groups()[0]
        if compareVersions(clang_version, "3.0") < 0:
            print 'Error: clang version 3.0 or newer required.'
            print '       Installed version:', clang_version
            Exit(1)
    else:
        print 'Error: Unable to determine clang version.'
        Exit(1)

    # clang has a few additional warnings that we disable,
    # tautological comparisons are allowed due to unsigned integers
    # being compared to constants that happen to be 0, and extraneous
    # parantheses are allowed due to Ruby's printing of the AST,
    # finally self assignments are allowed as the generated CPU code
    # is relying on this
    main.Append(CCFLAGS=['-Wno-tautological-compare',
                         '-Wno-parentheses',
                         '-Wno-self-assign',
                         # Some versions of libstdc++ (4.8?) seem to
                         # use struct hash and class hash
                         # interchangeably.
                         '-Wno-mismatched-tags',
                         ])

    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])

    # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
    # opposed to libstdc++, as the later is dated.
    if sys.platform == "darwin":
        main.Append(CXXFLAGS=['-stdlib=libc++'])
        main.Append(LIBS=['c++'])

else:
    print termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal,
    print "Don't know what compiler options to use for your compiler."
    print termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX']
    print termcap.Yellow + '       version:' + termcap.Normal,
    if not CXX_version:
        print termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +\
               termcap.Normal
    else:
        print CXX_version.replace('\n', '<nl>')
    print "       If you're trying to use a compiler other than GCC"
    print "       or clang, there appears to be something wrong with your"
    print "       environment."
    print "       "
    print "       If you are trying to use a compiler other than those listed"
    print "       above you will need to ease fix SConstruct and "
    print "       src/SConscript to support that compiler."
    Exit(1)

# Set up common yacc/bison flags (needed for Ruby)
main['YACCFLAGS'] = '-d'
main['YACCHXXFILESUFFIX'] = '.hh'

# Do this after we save setting back, or else we'll tack on an
# extra 'qdo' every time we run scons.
if main['BATCH']:
    main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
    main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
    main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
    main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
    main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']

if sys.platform == 'cygwin':
    # cygwin has some header file issues...
    main.Append(CCFLAGS=["-Wno-uninitialized"])

# Check for the protobuf compiler
protoc_version = readCommand([main['PROTOC'], '--version'],
                             exception='').split()

# First two words should be "libprotoc x.y.z"
if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
    print termcap.Yellow + termcap.Bold + \
        'Warning: Protocol buffer compiler (protoc) not found.\n' + \
        '         Please install protobuf-compiler for tracing support.' + \
        termcap.Normal
    main['PROTOC'] = False
else:
    # Based on the availability of the compress stream wrappers,
    # require 2.1.0
    min_protoc_version = '2.1.0'
    if compareVersions(protoc_version[1], min_protoc_version) < 0:
        print termcap.Yellow + termcap.Bold + \
            'Warning: protoc version', min_protoc_version, \
            'or newer required.\n' + \
            '         Installed version:', protoc_version[1], \
            termcap.Normal
        main['PROTOC'] = False
    else:
        # Attempt to determine the appropriate include path and
        # library path using pkg-config, that means we also need to
        # check for pkg-config. Note that it is possible to use
        # protobuf without the involvement of pkg-config. Later on we
        # check go a library config check and at that point the test
        # will fail if libprotobuf cannot be found.
        if readCommand(['pkg-config', '--version'], exception=''):
            try:
                # Attempt to establish what linking flags to add for protobuf
                # using pkg-config
                main.ParseConfig('pkg-config --cflags --libs-only-L protobuf')
            except:
                print termcap.Yellow + termcap.Bold + \
                    'Warning: pkg-config could not get protobuf flags.' + \
                    termcap.Normal

# Check for SWIG
if not main.has_key('SWIG'):
    print 'Error: SWIG utility not found.'
    print '       Please install (see http://www.swig.org) and retry.'
    Exit(1)

# Check for appropriate SWIG version
swig_version = readCommand([main['SWIG'], '-version'], exception='').split()
# First 3 words should be "SWIG Version x.y.z"
if len(swig_version) < 3 or \
        swig_version[0] != 'SWIG' or swig_version[1] != 'Version':
    print 'Error determining SWIG version.'
    Exit(1)

min_swig_version = '2.0.4'
if compareVersions(swig_version[2], min_swig_version) < 0:
    print 'Error: SWIG version', min_swig_version, 'or newer required.'
    print '       Installed version:', swig_version[2]
    Exit(1)

# Check for known incompatibilities. The standard library shipped with
# gcc >= 4.9 does not play well with swig versions prior to 3.0
if main['GCC'] and compareVersions(gcc_version, '4.9') >= 0 and \
        compareVersions(swig_version[2], '3.0') < 0:
    print termcap.Yellow + termcap.Bold + \
        'Warning: This combination of gcc and swig have' + \
        ' known incompatibilities.\n' + \
        '         If you encounter build problems, please update ' + \
        'swig to 3.0 or later.' + \
        termcap.Normal

# Set up SWIG flags & scanner
swig_flags=Split('-c++ -python -modern -templatereduce $_CPPINCFLAGS')
main.Append(SWIGFLAGS=swig_flags)

# Check for 'timeout' from GNU coreutils. If present, regressions will
# be run with a time limit. We require version 8.13 since we rely on
# support for the '--foreground' option.
timeout_lines = readCommand(['timeout', '--version'],
                            exception='').splitlines()
# Get the first line and tokenize it
timeout_version = timeout_lines[0].split() if timeout_lines else []
main['TIMEOUT'] =  timeout_version and \
    compareVersions(timeout_version[-1], '8.13') >= 0

# filter out all existing swig scanners, they mess up the dependency
# stuff for some reason
scanners = []
for scanner in main['SCANNERS']:
    skeys = scanner.skeys
    if skeys == '.i':
        continue

    if isinstance(skeys, (list, tuple)) and '.i' in skeys:
        continue

    scanners.append(scanner)

# add the new swig scanner that we like better
from SCons.Scanner import ClassicCPP as CPPScanner
swig_inc_re = '^[ \t]*[%,#][ \t]*(?:include|import)[ \t]*(<|")([^>"]+)(>|")'
scanners.append(CPPScanner("SwigScan", [ ".i" ], "CPPPATH", swig_inc_re))

# replace the scanners list that has what we want
main['SCANNERS'] = scanners

# Add a custom Check function to the Configure context so that we can
# figure out if the compiler adds leading underscores to global
# variables.  This is needed for the autogenerated asm files that we
# use for embedding the python code.
def CheckLeading(context):
    context.Message("Checking for leading underscore in global variables...")
    # 1) Define a global variable called x from asm so the C compiler
    #    won't change the symbol at all.
    # 2) Declare that variable.
    # 3) Use the variable
    #
    # If the compiler prepends an underscore, this will successfully
    # link because the external symbol 'x' will be called '_x' which
    # was defined by the asm statement.  If the compiler does not
    # prepend an underscore, this will not successfully link because
    # '_x' will have been defined by assembly, while the C portion of
    # the code will be trying to use 'x'
    ret = context.TryLink('''
        asm(".globl _x; _x: .byte 0");
        extern int x;
        int main() { return x; }
        ''', extension=".c")
    context.env.Append(LEADING_UNDERSCORE=ret)
    context.Result(ret)
    return ret

# Add a custom Check function to test for structure members.
def CheckMember(context, include, decl, member, include_quotes="<>"):
    context.Message("Checking for member %s in %s..." %
                    (member, decl))
    text = """
#include %(header)s
int main(){
  %(decl)s test;
  (void)test.%(member)s;
  return 0;
};
""" % { "header" : include_quotes[0] + include + include_quotes[1],
        "decl" : decl,
        "member" : member,
        }

    ret = context.TryCompile(text, extension=".cc")
    context.Result(ret)
    return ret

# Platform-specific configuration.  Note again that we assume that all
# builds under a given build root run on the same host platform.
conf = Configure(main,
                 conf_dir = joinpath(build_root, '.scons_config'),
                 log_file = joinpath(build_root, 'scons_config.log'),
                 custom_tests = {
        'CheckLeading' : CheckLeading,
        'CheckMember' : CheckMember,
        })

# Check for leading underscores.  Don't really need to worry either
# way so don't need to check the return code.
conf.CheckLeading()

# Check if we should compile a 64 bit binary on Mac OS X/Darwin
try:
    import platform
    uname = platform.uname()
    if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
        if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
            main.Append(CCFLAGS=['-arch', 'x86_64'])
            main.Append(CFLAGS=['-arch', 'x86_64'])
            main.Append(LINKFLAGS=['-arch', 'x86_64'])
            main.Append(ASFLAGS=['-arch', 'x86_64'])
except:
    pass

# Recent versions of scons substitute a "Null" object for Configure()
# when configuration isn't necessary, e.g., if the "--help" option is
# present.  Unfortuantely this Null object always returns false,
# breaking all our configuration checks.  We replace it with our own
# more optimistic null object that returns True instead.
if not conf:
    def NullCheck(*args, **kwargs):
        return True

    class NullConf:
        def __init__(self, env):
            self.env = env
        def Finish(self):
            return self.env
        def __getattr__(self, mname):
            return NullCheck

    conf = NullConf(main)

# Cache build files in the supplied directory.
if main['M5_BUILD_CACHE']:
    print 'Using build cache located at', main['M5_BUILD_CACHE']
    CacheDir(main['M5_BUILD_CACHE'])

if not GetOption('without_python'):
    # Find Python include and library directories for embedding the
    # interpreter. We rely on python-config to resolve the appropriate
    # includes and linker flags. ParseConfig does not seem to understand
    # the more exotic linker flags such as -Xlinker and -export-dynamic so
    # we add them explicitly below. If you want to link in an alternate
    # version of python, see above for instructions on how to invoke
    # scons with the appropriate PATH set.
    #
    # First we check if python2-config exists, else we use python-config
    python_config = readCommand(['which', 'python2-config'],
                                exception='').strip()
    if not os.path.exists(python_config):
        python_config = readCommand(['which', 'python-config'],
                                    exception='').strip()
    py_includes = readCommand([python_config, '--includes'],
                              exception='').split()
    # Strip the -I from the include folders before adding them to the
    # CPPPATH
    main.Append(CPPPATH=map(lambda inc: inc[2:], py_includes))

    # Read the linker flags and split them into libraries and other link
    # flags. The libraries are added later through the call the CheckLib.
    py_ld_flags = readCommand([python_config, '--ldflags'],
        exception='').split()
    py_libs = []
    for lib in py_ld_flags:
         if not lib.startswith('-l'):
             main.Append(LINKFLAGS=[lib])
         else:
             lib = lib[2:]
             if lib not in py_libs:
                 py_libs.append(lib)

    # verify that this stuff works
    if not conf.CheckHeader('Python.h', '<>'):
        print "Error: can't find Python.h header in", py_includes
        print "Install Python headers (package python-dev on Ubuntu and RedHat)"
        Exit(1)

    for lib in py_libs:
        if not conf.CheckLib(lib):
            print "Error: can't find library %s required by python" % lib
            Exit(1)

# On Solaris you need to use libsocket for socket ops
if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
   if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
       print "Can't find library with socket calls (e.g. accept())"
       Exit(1)

# Check for zlib.  If the check passes, libz will be automatically
# added to the LIBS environment variable.
if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
    print 'Error: did not find needed zlib compression library '\
          'and/or zlib.h header file.'
    print '       Please install zlib and try again.'
    Exit(1)

# If we have the protobuf compiler, also make sure we have the
# development libraries. If the check passes, libprotobuf will be
# automatically added to the LIBS environment variable. After
# this, we can use the HAVE_PROTOBUF flag to determine if we have
# got both protoc and libprotobuf available.
main['HAVE_PROTOBUF'] = main['PROTOC'] and \
    conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
                            'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')

# If we have the compiler but not the library, print another warning.
if main['PROTOC'] and not main['HAVE_PROTOBUF']:
    print termcap.Yellow + termcap.Bold + \
        'Warning: did not find protocol buffer library and/or headers.\n' + \
    '       Please install libprotobuf-dev for tracing support.' + \
    termcap.Normal

# Check for librt.
have_posix_clock = \
    conf.CheckLibWithHeader(None, 'time.h', 'C',
                            'clock_nanosleep(0,0,NULL,NULL);') or \
    conf.CheckLibWithHeader('rt', 'time.h', 'C',
                            'clock_nanosleep(0,0,NULL,NULL);')

have_posix_timers = \
    conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
                            'timer_create(CLOCK_MONOTONIC, NULL, NULL);')

if not GetOption('without_tcmalloc'):
    if conf.CheckLib('tcmalloc'):
        main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
    elif conf.CheckLib('tcmalloc_minimal'):
        main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
    else:
        print termcap.Yellow + termcap.Bold + \
              "You can get a 12% performance improvement by "\
              "installing tcmalloc (libgoogle-perftools-dev package "\
              "on Ubuntu or RedHat)." + termcap.Normal

if not have_posix_clock:
    print "Can't find library for POSIX clocks."

# Check for <fenv.h> (C99 FP environment control)
have_fenv = conf.CheckHeader('fenv.h', '<>')
if not have_fenv:
    print "Warning: Header file <fenv.h> not found."
    print "         This host has no IEEE FP rounding mode control."

# Check if we should enable KVM-based hardware virtualization. The API
# we rely on exists since version 2.6.36 of the kernel, but somehow
# the KVM_API_VERSION does not reflect the change. We test for one of
# the types as a fall back.
have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
if not have_kvm:
    print "Info: Compatible header file <linux/kvm.h> not found, " \
        "disabling KVM support."

# x86 needs support for xsave. We test for the structure here since we
# won't be able to run new tests by the time we know which ISA we're
# targeting.
have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
                                    '#include <linux/kvm.h>') != 0

# Check if the requested target ISA is compatible with the host
def is_isa_kvm_compatible(isa):
    try:
        import platform
        host_isa = platform.machine()
    except:
        print "Warning: Failed to determine host ISA."
        return False

    if not have_posix_timers:
        print "Warning: Can not enable KVM, host seems to lack support " \
            "for POSIX timers"
        return False

    if isa == "arm":
        return host_isa in ( "armv7l", "aarch64" )
    elif isa == "x86":
        if host_isa != "x86_64":
            return False

        if not have_kvm_xsave:
            print "KVM on x86 requires xsave support in kernel headers."
            return False

        return True
    else:
        return False


# Check if the exclude_host attribute is available. We want this to
# get accurate instruction counts in KVM.
main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
    'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')


######################################################################
#
# Finish the configuration
#
main = conf.Finish()

######################################################################
#
# Collect all non-global variables
#

# Define the universe of supported ISAs
all_isa_list = [ ]
Export('all_isa_list')

class CpuModel(object):
    '''The CpuModel class encapsulates everything the ISA parser needs to
    know about a particular CPU model.'''

    # Dict of available CPU model objects.  Accessible as CpuModel.dict.
    dict = {}

    # Constructor.  Automatically adds models to CpuModel.dict.
    def __init__(self, name, default=False):
        self.name = name           # name of model

        # This cpu is enabled by default
        self.default = default

        # Add self to dict
        if name in CpuModel.dict:
            raise AttributeError, "CpuModel '%s' already registered" % name
        CpuModel.dict[name] = self

Export('CpuModel')

# Sticky variables get saved in the variables file so they persist from
# one invocation to the next (unless overridden, in which case the new
# value becomes sticky).
sticky_vars = Variables(args=ARGUMENTS)
Export('sticky_vars')

# Sticky variables that should be exported
export_vars = []
Export('export_vars')

# For Ruby
all_protocols = []
Export('all_protocols')
protocol_dirs = []
Export('protocol_dirs')
slicc_includes = []
Export('slicc_includes')

# Walk the tree and execute all SConsopts scripts that wil add to the
# above variables
if GetOption('verbose'):
    print "Reading SConsopts"
for bdir in [ base_dir ] + extras_dir_list:
    if not isdir(bdir):
        print "Error: directory '%s' does not exist" % bdir
        Exit(1)
    for root, dirs, files in os.walk(bdir):
        if 'SConsopts' in files:
            if GetOption('verbose'):
                print "Reading", joinpath(root, 'SConsopts')
            SConscript(joinpath(root, 'SConsopts'))

all_isa_list.sort()

sticky_vars.AddVariables(
    EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
    ListVariable('CPU_MODELS', 'CPU models',
                 sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
                 sorted(CpuModel.dict.keys())),
    BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
                 False),
    BoolVariable('SS_COMPATIBLE_FP',
                 'Make floating-point results compatible with SimpleScalar',
                 False),
    BoolVariable('USE_SSE2',
                 'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
                 False),
    BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
    BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
    BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability', False),
    BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models', have_kvm),
    EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
                  all_protocols),
    )

# These variables get exported to #defines in config/*.hh (see src/SConscript).
export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'CP_ANNOTATE',
                'USE_POSIX_CLOCK', 'USE_KVM', 'PROTOCOL', 'HAVE_PROTOBUF',
                'HAVE_PERF_ATTR_EXCLUDE_HOST']

###################################################
#
# Define a SCons builder for configuration flag headers.
#
###################################################

# This function generates a config header file that #defines the
# variable symbol to the current variable setting (0 or 1).  The source
# operands are the name of the variable and a Value node containing the
# value of the variable.
def build_config_file(target, source, env):
    (variable, value) = [s.get_contents() for s in source]
    f = file(str(target[0]), 'w')
    print >> f, '#define', variable, value
    f.close()
    return None

# Combine the two functions into a scons Action object.
config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))

# The emitter munges the source & target node lists to reflect what
# we're really doing.
def config_emitter(target, source, env):
    # extract variable name from Builder arg
    variable = str(target[0])
    # True target is config header file
    target = joinpath('config', variable.lower() + '.hh')
    val = env[variable]
    if isinstance(val, bool):
        # Force value to 0/1
        val = int(val)
    elif isinstance(val, str):
        val = '"' + val + '"'

    # Sources are variable name & value (packaged in SCons Value nodes)
    return ([target], [Value(variable), Value(val)])

config_builder = Builder(emitter = config_emitter, action = config_action)

main.Append(BUILDERS = { 'ConfigFile' : config_builder })

# libelf build is shared across all configs in the build root.
main.SConscript('ext/libelf/SConscript',
                variant_dir = joinpath(build_root, 'libelf'))

# gzstream build is shared across all configs in the build root.
main.SConscript('ext/gzstream/SConscript',
                variant_dir = joinpath(build_root, 'gzstream'))

# libfdt build is shared across all configs in the build root.
main.SConscript('ext/libfdt/SConscript',
                variant_dir = joinpath(build_root, 'libfdt'))

# fputils build is shared across all configs in the build root.
main.SConscript('ext/fputils/SConscript',
                variant_dir = joinpath(build_root, 'fputils'))

# DRAMSim2 build is shared across all configs in the build root.
main.SConscript('ext/dramsim2/SConscript',
                variant_dir = joinpath(build_root, 'dramsim2'))

# DRAMPower build is shared across all configs in the build root.
main.SConscript('ext/drampower/SConscript',
                variant_dir = joinpath(build_root, 'drampower'))

###################################################
#
# This function is used to set up a directory with switching headers
#
###################################################

main['ALL_ISA_LIST'] = all_isa_list
all_isa_deps = {}
def make_switching_dir(dname, switch_headers, env):
    # Generate the header.  target[0] is the full path of the output
    # header to generate.  'source' is a dummy variable, since we get the
    # list of ISAs from env['ALL_ISA_LIST'].
    def gen_switch_hdr(target, source, env):
        fname = str(target[0])
        isa = env['TARGET_ISA'].lower()
        try:
            f = open(fname, 'w')
            print >>f, '#include "%s/%s/%s"' % (dname, isa, basename(fname))
            f.close()
        except IOError:
            print "Failed to create %s" % fname
            raise

    # Build SCons Action object. 'varlist' specifies env vars that this
    # action depends on; when env['ALL_ISA_LIST'] changes these actions
    # should get re-executed.
    switch_hdr_action = MakeAction(gen_switch_hdr,
                          Transform("GENERATE"), varlist=['ALL_ISA_LIST'])

    # Instantiate actions for each header
    for hdr in switch_headers:
        env.Command(hdr, [], switch_hdr_action)

    isa_target = Dir('.').up().name.lower().replace('_', '-')
    env['PHONY_BASE'] = '#'+isa_target
    all_isa_deps[isa_target] = None

Export('make_switching_dir')

# all-isas -> all-deps -> all-environs -> all_targets
main.Alias('#all-isas', [])
main.Alias('#all-deps', '#all-isas')

# Dummy target to ensure all environments are created before telling
# SCons what to actually make (the command line arguments).  We attach
# them to the dependence graph after the environments are complete.
ORIG_BUILD_TARGETS = list(BUILD_TARGETS) # force a copy; gets closure to work.
def environsComplete(target, source, env):
    for t in ORIG_BUILD_TARGETS:
        main.Depends('#all-targets', t)

# Each build/* switching_dir attaches its *-environs target to #all-environs.
main.Append(BUILDERS = {'CompleteEnvirons' :
                        Builder(action=MakeAction(environsComplete, None))})
main.CompleteEnvirons('#all-environs', [])

def doNothing(**ignored): pass
main.Append(BUILDERS = {'Dummy': Builder(action=MakeAction(doNothing, None))})

# The final target to which all the original targets ultimately get attached.
main.Dummy('#all-targets', '#all-environs')
BUILD_TARGETS[:] = ['#all-targets']

###################################################
#
# Define build environments for selected configurations.
#
###################################################

for variant_path in variant_paths:
    if not GetOption('silent'):
        print "Building in", variant_path

    # Make a copy of the build-root environment to use for this config.
    env = main.Clone()
    env['BUILDDIR'] = variant_path

    # variant_dir is the tail component of build path, and is used to
    # determine the build parameters (e.g., 'ALPHA_SE')
    (build_root, variant_dir) = splitpath(variant_path)

    # Set env variables according to the build directory config.
    sticky_vars.files = []
    # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
    # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
    # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
    current_vars_file = joinpath(build_root, 'variables', variant_dir)
    if isfile(current_vars_file):
        sticky_vars.files.append(current_vars_file)
        if not GetOption('silent'):
            print "Using saved variables file %s" % current_vars_file
    else:
        # Build dir-specific variables file doesn't exist.

        # Make sure the directory is there so we can create it later
        opt_dir = dirname(current_vars_file)
        if not isdir(opt_dir):
            mkdir(opt_dir)

        # Get default build variables from source tree.  Variables are
        # normally determined by name of $VARIANT_DIR, but can be
        # overridden by '--default=' arg on command line.
        default = GetOption('default')
        opts_dir = joinpath(main.root.abspath, 'build_opts')
        if default:
            default_vars_files = [joinpath(build_root, 'variables', default),
                                  joinpath(opts_dir, default)]
        else:
            default_vars_files = [joinpath(opts_dir, variant_dir)]
        existing_files = filter(isfile, default_vars_files)
        if existing_files:
            default_vars_file = existing_files[0]
            sticky_vars.files.append(default_vars_file)
            print "Variables file %s not found,\n  using defaults in %s" \
                  % (current_vars_file, default_vars_file)
        else:
            print "Error: cannot find variables file %s or " \
                  "default file(s) %s" \
                  % (current_vars_file, ' or '.join(default_vars_files))
            Exit(1)

    # Apply current variable settings to env
    sticky_vars.Update(env)

    help_texts["local_vars"] += \
        "Build variables for %s:\n" % variant_dir \
                 + sticky_vars.GenerateHelpText(env)

    # Process variable settings.

    if not have_fenv and env['USE_FENV']:
        print "Warning: <fenv.h> not available; " \
              "forcing USE_FENV to False in", variant_dir + "."
        env['USE_FENV'] = False

    if not env['USE_FENV']:
        print "Warning: No IEEE FP rounding mode control in", variant_dir + "."
        print "         FP results may deviate slightly from other platforms."

    if env['EFENCE']:
        env.Append(LIBS=['efence'])

    if env['USE_KVM']:
        if not have_kvm:
            print "Warning: Can not enable KVM, host seems to lack KVM support"
            env['USE_KVM'] = False
        elif not is_isa_kvm_compatible(env['TARGET_ISA']):
            print "Info: KVM support disabled due to unsupported host and " \
                "target ISA combination"
            env['USE_KVM'] = False

    # Warn about missing optional functionality
    if env['USE_KVM']:
        if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
            print "Warning: perf_event headers lack support for the " \
                "exclude_host attribute. KVM instruction counts will " \
                "be inaccurate."

    # Save sticky variable settings back to current variables file
    sticky_vars.Save(current_vars_file, env)

    if env['USE_SSE2']:
        env.Append(CCFLAGS=['-msse2'])

    # The src/SConscript file sets up the build rules in 'env' according
    # to the configured variables.  It returns a list of environments,
    # one for each variant build (debug, opt, etc.)
    SConscript('src/SConscript', variant_dir = variant_path, exports = 'env')

def pairwise(iterable):
    "s -> (s0,s1), (s1,s2), (s2, s3), ..."
    a, b = itertools.tee(iterable)
    b.next()
    return itertools.izip(a, b)

# Create false dependencies so SCons will parse ISAs, establish
# dependencies, and setup the build Environments serially. Either
# SCons (likely) and/or our SConscripts (possibly) cannot cope with -j
# greater than 1. It appears to be standard race condition stuff; it
# doesn't always fail, but usually, and the behaviors are different.
# Every time I tried to remove this, builds would fail in some
# creative new way. So, don't do that. You'll want to, though, because
# tests/SConscript takes a long time to make its Environments.
for t1, t2 in pairwise(sorted(all_isa_deps.iterkeys())):
    main.Depends('#%s-deps'     % t2, '#%s-deps'     % t1)
    main.Depends('#%s-environs' % t2, '#%s-environs' % t1)

# base help text
Help('''
Usage: scons [scons options] [build variables] [target(s)]

Extra scons options:
%(options)s

Global build variables:
%(global_vars)s

%(local_vars)s
''' % help_texts)