SConstruct

   1 # -*- mode:python -*-
   2
   3 # Copyright (c) 2013, 2015-2020 ARM Limited
   4 # All rights reserved.
   5 #
   6 # The license below extends only to copyright in the software and shall
   7 # not be construed as granting a license to any other intellectual
   8 # property including but not limited to intellectual property relating
   9 # to a hardware implementation of the functionality of the software
  10 # licensed hereunder.  You may use the software subject to the license
  11 # terms below provided that you ensure that this notice is replicated
  12 # unmodified and in its entirety in all distributions of the software,
  13 # modified or unmodified, in source code or in binary form.
  14 #
  15 # Copyright (c) 2011 Advanced Micro Devices, Inc.
  16 # Copyright (c) 2009 The Hewlett-Packard Development Company
  17 # Copyright (c) 2004-2005 The Regents of The University of Michigan
  18 # All rights reserved.
  19 #
  20 # Redistribution and use in source and binary forms, with or without
  21 # modification, are permitted provided that the following conditions are
  22 # met: redistributions of source code must retain the above copyright
  23 # notice, this list of conditions and the following disclaimer;
  24 # redistributions in binary form must reproduce the above copyright
  25 # notice, this list of conditions and the following disclaimer in the
  26 # documentation and/or other materials provided with the distribution;
  27 # neither the name of the copyright holders nor the names of its
  28 # contributors may be used to endorse or promote products derived from
  29 # this software without specific prior written permission.
  30 #
  31 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  34 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  36 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  37 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  38 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  39 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  40 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  41 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  42
  43 ###################################################
  44 #
  45 # SCons top-level build description (SConstruct) file.
  46 #
  47 # While in this directory ('gem5'), just type 'scons' to build the default
  48 # configuration (see below), or type 'scons build/<CONFIG>/<binary>'
  49 # to build some other configuration (e.g., 'build/X86/gem5.opt' for
  50 # the optimized full-system version).
  51 #
  52 # You can build gem5 in a different directory as long as there is a
  53 # 'build/<CONFIG>' somewhere along the target path.  The build system
  54 # expects that all configs under the same build directory are being
  55 # built for the same host system.
  56 #
  57 # Examples:
  58 #
  59 #   The following two commands are equivalent.  The '-u' option tells
  60 #   scons to search up the directory tree for this SConstruct file.
  61 #   % cd <path-to-src>/gem5 ; scons build/X86/gem5.debug
  62 #   % cd <path-to-src>/gem5/build/X86; scons -u gem5.debug
  63 #
  64 #   The following two commands are equivalent and demonstrate building
  65 #   in a directory outside of the source tree.  The '-C' option tells
  66 #   scons to chdir to the specified directory to find this SConstruct
  67 #   file.
  68 #   % cd <path-to-src>/gem5 ; scons /local/foo/build/X86/gem5.debug
  69 #   % cd /local/foo/build/X86; scons -C <path-to-src>/gem5 gem5.debug
  70 #
  71 # You can use 'scons -H' to print scons options.  If you're in this
  72 # 'gem5' directory (or use -u or -C to tell scons where to find this
  73 # file), you can use 'scons -h' to print all the gem5-specific build
  74 # options as well.
  75 #
  76 ###################################################
  77
  78 from __future__ import print_function
  79
  80 # Global Python includes
  81 import atexit
  82 import itertools
  83 import os
  84 import re
  85 import shutil
  86 import subprocess
  87 import sys
  88
  89 from os import mkdir, environ
  90 from os.path import abspath, basename, dirname, expanduser, normpath
  91 from os.path import exists,  isdir, isfile
  92 from os.path import join as joinpath, split as splitpath
  93 from re import match
  94
  95 # SCons includes
  96 import SCons
  97 import SCons.Node
  98 import SCons.Node.FS
  99
 100 from m5.util import compareVersions, readCommand, readCommandWithReturn
 101
 102 AddOption('--colors', dest='use_colors', action='store_true',
 103           help="Add color to abbreviated scons output")
 104 AddOption('--no-colors', dest='use_colors', action='store_false',
 105           help="Don't add color to abbreviated scons output")
 106 AddOption('--with-cxx-config', action='store_true',
 107           help="Build with support for C++-based configuration")
 108 AddOption('--default',
 109           help='Override which build_opts file to use for defaults')
 110 AddOption('--ignore-style', action='store_true',
 111           help='Disable style checking hooks')
 112 AddOption('--gold-linker', action='store_true', help='Use the gold linker')
 113 AddOption('--no-lto', action='store_true',
 114           help='Disable Link-Time Optimization for fast')
 115 AddOption('--force-lto', action='store_true',
 116           help='Use Link-Time Optimization instead of partial linking' +
 117                ' when the compiler doesn\'t support using them together.')
 118 AddOption('--verbose', action='store_true',
 119           help='Print full tool command lines')
 120 AddOption('--without-python', action='store_true',
 121           help='Build without Python configuration support')
 122 AddOption('--without-tcmalloc', action='store_true',
 123           help='Disable linking against tcmalloc')
 124 AddOption('--with-ubsan', action='store_true',
 125           help='Build with Undefined Behavior Sanitizer if available')
 126 AddOption('--with-asan', action='store_true',
 127           help='Build with Address Sanitizer if available')
 128 AddOption('--with-systemc-tests', action='store_true',
 129           help='Build systemc tests')
 130
 131 from gem5_scons import Transform, error, warning, summarize_warnings
 132
 133 if GetOption('no_lto') and GetOption('force_lto'):
 134     error('--no-lto and --force-lto are mutually exclusive')
 135
 136 ########################################################################
 137 #
 138 # Set up the main build environment.
 139 #
 140 ########################################################################
 141
 142 main = Environment()
 143
 144 from gem5_scons.util import get_termcap
 145 termcap = get_termcap()
 146
 147 main_dict_keys = main.Dictionary().keys()
 148
 149 # Check that we have a C/C++ compiler
 150 if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
 151     error("No C++ compiler installed (package g++ on Ubuntu and RedHat)")
 152
 153 ###################################################
 154 #
 155 # Figure out which configurations to set up based on the path(s) of
 156 # the target(s).
 157 #
 158 ###################################################
 159
 160 # Find default configuration & binary.
 161 Default(environ.get('M5_DEFAULT_BINARY', 'build/ARM/gem5.debug'))
 162
 163 # helper function: find last occurrence of element in list
 164 def rfind(l, elt, offs = -1):
 165     for i in range(len(l)+offs, 0, -1):
 166         if l[i] == elt:
 167             return i
 168     raise ValueError("element not found")
 169
 170 # Take a list of paths (or SCons Nodes) and return a list with all
 171 # paths made absolute and ~-expanded.  Paths will be interpreted
 172 # relative to the launch directory unless a different root is provided
 173 def makePathListAbsolute(path_list, root=GetLaunchDir()):
 174     return [abspath(joinpath(root, expanduser(str(p))))
 175             for p in path_list]
 176
 177 # Each target must have 'build' in the interior of the path; the
 178 # directory below this will determine the build parameters.  For
 179 # example, for target 'foo/bar/build/X86/arch/x86/blah.do' we
 180 # recognize that X86 specifies the configuration because it
 181 # follow 'build' in the build path.
 182
 183 # The funky assignment to "[:]" is needed to replace the list contents
 184 # in place rather than reassign the symbol to a new list, which
 185 # doesn't work (obviously!).
 186 BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
 187
 188 # Generate a list of the unique build roots and configs that the
 189 # collected targets reference.
 190 variant_paths = []
 191 build_root = None
 192 for t in BUILD_TARGETS:
 193     path_dirs = t.split('/')
 194     try:
 195         build_top = rfind(path_dirs, 'build', -2)
 196     except:
 197         error("No non-leaf 'build' dir found on target path.", t)
 198     this_build_root = joinpath('/',*path_dirs[:build_top+1])
 199     if not build_root:
 200         build_root = this_build_root
 201     else:
 202         if this_build_root != build_root:
 203             error("build targets not under same build root\n"
 204                   "  %s\n  %s" % (build_root, this_build_root))
 205     variant_path = joinpath('/',*path_dirs[:build_top+2])
 206     if variant_path not in variant_paths:
 207         variant_paths.append(variant_path)
 208
 209 # Make sure build_root exists (might not if this is the first build there)
 210 if not isdir(build_root):
 211     mkdir(build_root)
 212 main['BUILDROOT'] = build_root
 213
 214 Export('main')
 215
 216 main.SConsignFile(joinpath(build_root, "sconsign"))
 217
 218 # Default duplicate option is to use hard links, but this messes up
 219 # when you use emacs to edit a file in the target dir, as emacs moves
 220 # file to file~ then copies to file, breaking the link.  Symbolic
 221 # (soft) links work better.
 222 main.SetOption('duplicate', 'soft-copy')
 223
 224 #
 225 # Set up global sticky variables... these are common to an entire build
 226 # tree (not specific to a particular build like X86)
 227 #
 228
 229 global_vars_file = joinpath(build_root, 'variables.global')
 230
 231 global_vars = Variables(global_vars_file, args=ARGUMENTS)
 232
 233 global_vars.AddVariables(
 234     ('CC', 'C compiler', environ.get('CC', main['CC'])),
 235     ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
 236     ('CCFLAGS_EXTRA', 'Extra C and C++ compiler flags', ''),
 237     ('LDFLAGS_EXTRA', 'Extra linker flags', ''),
 238     ('MARSHAL_CCFLAGS_EXTRA', 'Extra C and C++ marshal compiler flags', ''),
 239     ('MARSHAL_LDFLAGS_EXTRA', 'Extra marshal linker flags', ''),
 240     ('PYTHON_CONFIG', 'Python config binary to use',
 241      [ 'python3-config', 'python-config', 'python2.7-config', 'python2-config']
 242     ),
 243     ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
 244     ('BATCH', 'Use batch pool for build and tests', False),
 245     ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
 246     ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
 247     ('EXTRAS', 'Add extra directories to the compilation', '')
 248     )
 249
 250 # Update main environment with values from ARGUMENTS & global_vars_file
 251 global_vars.Update(main)
 252 Help('''
 253 Global build variables:
 254 {help}
 255 '''.format(help=global_vars.GenerateHelpText(main)), append=True)
 256
 257 # Save sticky variable settings back to current variables file
 258 global_vars.Save(global_vars_file, main)
 259
 260 # Parse EXTRAS variable to build list of all directories where we're
 261 # look for sources etc.  This list is exported as extras_dir_list.
 262 base_dir = main.srcdir.abspath
 263 if main['EXTRAS']:
 264     extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
 265 else:
 266     extras_dir_list = []
 267
 268 Export('base_dir')
 269 Export('extras_dir_list')
 270
 271 # the ext directory should be on the #includes path
 272 main.Append(CPPPATH=[Dir('ext')])
 273
 274 # Add shared top-level headers
 275 main.Prepend(CPPPATH=Dir('include'))
 276
 277 if GetOption('verbose'):
 278     def MakeAction(action, string, *args, **kwargs):
 279         return Action(action, *args, **kwargs)
 280 else:
 281     MakeAction = Action
 282     main['CCCOMSTR']        = Transform("CC")
 283     main['CXXCOMSTR']       = Transform("CXX")
 284     main['ASCOMSTR']        = Transform("AS")
 285     main['ARCOMSTR']        = Transform("AR", 0)
 286     main['LINKCOMSTR']      = Transform("LINK", 0)
 287     main['SHLINKCOMSTR']    = Transform("SHLINK", 0)
 288     main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
 289     main['M4COMSTR']        = Transform("M4")
 290     main['SHCCCOMSTR']      = Transform("SHCC")
 291     main['SHCXXCOMSTR']     = Transform("SHCXX")
 292 Export('MakeAction')
 293
 294 # Initialize the Link-Time Optimization (LTO) flags
 295 main['LTO_CCFLAGS'] = []
 296 main['LTO_LDFLAGS'] = []
 297
 298 # According to the readme, tcmalloc works best if the compiler doesn't
 299 # assume that we're using the builtin malloc and friends. These flags
 300 # are compiler-specific, so we need to set them after we detect which
 301 # compiler we're using.
 302 main['TCMALLOC_CCFLAGS'] = []
 303
 304 CXX_version = readCommand([main['CXX'],'--version'], exception=False)
 305 CXX_V = readCommand([main['CXX'],'-V'], exception=False)
 306
 307 main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
 308 main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
 309 if main['GCC'] + main['CLANG'] > 1:
 310     error('Two compilers enabled at once?')
 311
 312 # Set up default C++ compiler flags
 313 if main['GCC'] or main['CLANG']:
 314     # As gcc and clang share many flags, do the common parts here
 315     main.Append(CCFLAGS=['-pipe'])
 316     main.Append(CCFLAGS=['-fno-strict-aliasing'])
 317     # Enable -Wall and -Wextra and then disable the few warnings that
 318     # we consistently violate
 319     main.Append(CCFLAGS=['-Wall', '-Wundef', '-Wextra',
 320                          '-Wno-sign-compare', '-Wno-unused-parameter'])
 321     # We always compile using C++11
 322     main.Append(CXXFLAGS=['-std=c++11'])
 323     if sys.platform.startswith('freebsd'):
 324         main.Append(CCFLAGS=['-I/usr/local/include'])
 325         main.Append(CXXFLAGS=['-I/usr/local/include'])
 326
 327     # On Mac OS X/Darwin the default linker doesn't support the
 328     # option --as-needed
 329     if sys.platform != "darwin":
 330         main.Append(LINKFLAGS='-Wl,--as-needed')
 331     main['FILTER_PSHLINKFLAGS'] = lambda x: str(x).replace(' -shared', '')
 332     main['PSHLINKFLAGS'] = main.subst('${FILTER_PSHLINKFLAGS(SHLINKFLAGS)}')
 333     if GetOption('gold_linker'):
 334         main.Append(LINKFLAGS='-fuse-ld=gold')
 335     main['PLINKFLAGS'] = main.get('LINKFLAGS')
 336     shared_partial_flags = ['-r', '-nostdlib']
 337     main.Append(PSHLINKFLAGS=shared_partial_flags)
 338     main.Append(PLINKFLAGS=shared_partial_flags)
 339
 340     # Treat warnings as errors but white list some warnings that we
 341     # want to allow (e.g., deprecation warnings).
 342     main.Append(CCFLAGS=['-Werror',
 343                          '-Wno-error=deprecated-declarations',
 344                          '-Wno-error=deprecated',
 345                         ])
 346 else:
 347     error('\n'.join((
 348           "Don't know what compiler options to use for your compiler.",
 349           "compiler: " + main['CXX'],
 350           "version: " + CXX_version.replace('\n', '<nl>') if
 351                 CXX_version else 'COMMAND NOT FOUND!',
 352           "If you're trying to use a compiler other than GCC",
 353           "or clang, there appears to be something wrong with your",
 354           "environment.",
 355           "",
 356           "If you are trying to use a compiler other than those listed",
 357           "above you will need to ease fix SConstruct and ",
 358           "src/SConscript to support that compiler.")))
 359
 360 if main['GCC']:
 361     gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
 362     if compareVersions(gcc_version, "5") < 0:
 363         error('gcc version 5 or newer required.\n'
 364               'Installed version:', gcc_version)
 365         Exit(1)
 366
 367     main['GCC_VERSION'] = gcc_version
 368
 369     # Incremental linking with LTO is currently broken in gcc versions
 370     # 4.9 and above. A version where everything works completely hasn't
 371     # yet been identified.
 372     #
 373     # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548
 374     main['BROKEN_INCREMENTAL_LTO'] = True
 375
 376     if compareVersions(gcc_version, '6.0') >= 0:
 377         # gcc versions 6.0 and greater accept an -flinker-output flag which
 378         # selects what type of output the linker should generate. This is
 379         # necessary for incremental lto to work, but is also broken in
 380         # current versions of gcc. It may not be necessary in future
 381         # versions. We add it here since it might be, and as a reminder that
 382         # it exists. It's excluded if lto is being forced.
 383         #
 384         # https://gcc.gnu.org/gcc-6/changes.html
 385         # https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03161.html
 386         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69866
 387         if not GetOption('force_lto'):
 388             main.Append(PSHLINKFLAGS='-flinker-output=rel')
 389             main.Append(PLINKFLAGS='-flinker-output=rel')
 390
 391     disable_lto = GetOption('no_lto')
 392     if not disable_lto and main.get('BROKEN_INCREMENTAL_LTO', False) and \
 393             not GetOption('force_lto'):
 394         warning('Your compiler doesn\'t support incremental linking and lto '
 395                 'at the same time, so lto is being disabled. To force lto on '
 396                 'anyway, use the --force-lto option. That will disable '
 397                 'partial linking.')
 398         disable_lto = True
 399
 400     # Add the appropriate Link-Time Optimization (LTO) flags
 401     # unless LTO is explicitly turned off. Note that these flags
 402     # are only used by the fast target.
 403     if not disable_lto:
 404         # Pass the LTO flag when compiling to produce GIMPLE
 405         # output, we merely create the flags here and only append
 406         # them later
 407         main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 408
 409         # Use the same amount of jobs for LTO as we are running
 410         # scons with
 411         main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 412
 413     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
 414                                   '-fno-builtin-realloc', '-fno-builtin-free'])
 415
 416 elif main['CLANG']:
 417     clang_version_re = re.compile(".* version (\d+\.\d+)")
 418     clang_version_match = clang_version_re.search(CXX_version)
 419     if (clang_version_match):
 420         clang_version = clang_version_match.groups()[0]
 421         if compareVersions(clang_version, "3.1") < 0:
 422             error('clang version 3.1 or newer required.\n'
 423                   'Installed version:', clang_version)
 424     else:
 425         error('Unable to determine clang version.')
 426
 427     # clang has a few additional warnings that we disable, extraneous
 428     # parantheses are allowed due to Ruby's printing of the AST,
 429     # finally self assignments are allowed as the generated CPU code
 430     # is relying on this
 431     main.Append(CCFLAGS=['-Wno-parentheses',
 432                          '-Wno-self-assign',
 433                          # Some versions of libstdc++ (4.8?) seem to
 434                          # use struct hash and class hash
 435                          # interchangeably.
 436                          '-Wno-mismatched-tags',
 437                          ])
 438     if sys.platform != "darwin" and \
 439        compareVersions(clang_version, "10.0") >= 0:
 440         main.Append(CCFLAGS=['-Wno-c99-designator'])
 441
 442     if compareVersions(clang_version, "8.0") >= 0:
 443         main.Append(CCFLAGS=['-Wno-defaulted-function-deleted'])
 444
 445     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
 446
 447     # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
 448     # opposed to libstdc++, as the later is dated.
 449     if sys.platform == "darwin":
 450         main.Append(CXXFLAGS=['-stdlib=libc++'])
 451         main.Append(LIBS=['c++'])
 452
 453     # On FreeBSD we need libthr.
 454     if sys.platform.startswith('freebsd'):
 455         main.Append(LIBS=['thr'])
 456
 457 # Add sanitizers flags
 458 sanitizers=[]
 459 if GetOption('with_ubsan'):
 460     sanitizers.append('undefined')
 461 if GetOption('with_asan'):
 462     # Available for gcc >= 5 or llvm >= 3.1 both a requirement
 463     # by the build system
 464     sanitizers.append('address')
 465     suppressions_file = Dir('util').File('lsan-suppressions').get_abspath()
 466     suppressions_opt = 'suppressions=%s' % suppressions_file
 467     main['ENV']['LSAN_OPTIONS'] = ':'.join([suppressions_opt,
 468                                             'print_suppressions=0'])
 469     print()
 470     warning('To suppress false positive leaks, set the LSAN_OPTIONS '
 471             'environment variable to "%s" when running gem5' %
 472             suppressions_opt)
 473     warning('LSAN_OPTIONS=suppressions=%s' % suppressions_opt)
 474     print()
 475 if sanitizers:
 476     sanitizers = ','.join(sanitizers)
 477     if main['GCC'] or main['CLANG']:
 478         main.Append(CCFLAGS=['-fsanitize=%s' % sanitizers,
 479                              '-fno-omit-frame-pointer'],
 480                     LINKFLAGS='-fsanitize=%s' % sanitizers)
 481     else:
 482         warning("Don't know how to enable %s sanitizer(s) for your "
 483                 "compiler." % sanitizers)
 484
 485 # Set up common yacc/bison flags (needed for Ruby)
 486 main['YACCFLAGS'] = '-d'
 487 main['YACCHXXFILESUFFIX'] = '.hh'
 488
 489 # Do this after we save setting back, or else we'll tack on an
 490 # extra 'qdo' every time we run scons.
 491 if main['BATCH']:
 492     main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
 493     main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
 494     main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
 495     main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
 496     main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
 497
 498 if sys.platform == 'cygwin':
 499     # cygwin has some header file issues...
 500     main.Append(CCFLAGS=["-Wno-uninitialized"])
 501
 502
 503 have_pkg_config = readCommand(['pkg-config', '--version'], exception='')
 504
 505 # Check for the protobuf compiler
 506 try:
 507     main['HAVE_PROTOC'] = True
 508     protoc_version = readCommand([main['PROTOC'], '--version']).split()
 509
 510     # First two words should be "libprotoc x.y.z"
 511     if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
 512         warning('Protocol buffer compiler (protoc) not found.\n'
 513                 'Please install protobuf-compiler for tracing support.')
 514         main['HAVE_PROTOC'] = False
 515     else:
 516         # Based on the availability of the compress stream wrappers,
 517         # require 2.1.0
 518         min_protoc_version = '2.1.0'
 519         if compareVersions(protoc_version[1], min_protoc_version) < 0:
 520             warning('protoc version', min_protoc_version,
 521                     'or newer required.\n'
 522                     'Installed version:', protoc_version[1])
 523             main['HAVE_PROTOC'] = False
 524         else:
 525             # Attempt to determine the appropriate include path and
 526             # library path using pkg-config, that means we also need to
 527             # check for pkg-config. Note that it is possible to use
 528             # protobuf without the involvement of pkg-config. Later on we
 529             # check go a library config check and at that point the test
 530             # will fail if libprotobuf cannot be found.
 531             if have_pkg_config:
 532                 try:
 533                     # Attempt to establish what linking flags to add for
 534                     # protobuf
 535                     # using pkg-config
 536                     main.ParseConfig(
 537                             'pkg-config --cflags --libs-only-L protobuf')
 538                 except:
 539                     warning('pkg-config could not get protobuf flags.')
 540 except Exception as e:
 541     warning('While checking protoc version:', str(e))
 542     main['HAVE_PROTOC'] = False
 543
 544 # Check for 'timeout' from GNU coreutils. If present, regressions will
 545 # be run with a time limit. We require version 8.13 since we rely on
 546 # support for the '--foreground' option.
 547 if sys.platform.startswith('freebsd'):
 548     timeout_lines = readCommand(['gtimeout', '--version'],
 549                                 exception='').splitlines()
 550 else:
 551     timeout_lines = readCommand(['timeout', '--version'],
 552                                 exception='').splitlines()
 553 # Get the first line and tokenize it
 554 timeout_version = timeout_lines[0].split() if timeout_lines else []
 555 main['TIMEOUT'] =  timeout_version and \
 556     compareVersions(timeout_version[-1], '8.13') >= 0
 557
 558 # Add a custom Check function to test for structure members.
 559 def CheckMember(context, include, decl, member, include_quotes="<>"):
 560     context.Message("Checking for member %s in %s..." %
 561                     (member, decl))
 562     text = """
 563 #include %(header)s
 564 int main(){
 565   %(decl)s test;
 566   (void)test.%(member)s;
 567   return 0;
 568 };
 569 """ % { "header" : include_quotes[0] + include + include_quotes[1],
 570         "decl" : decl,
 571         "member" : member,
 572         }
 573
 574     ret = context.TryCompile(text, extension=".cc")
 575     context.Result(ret)
 576     return ret
 577
 578 # Platform-specific configuration.  Note again that we assume that all
 579 # builds under a given build root run on the same host platform.
 580 conf = Configure(main,
 581                  conf_dir = joinpath(build_root, '.scons_config'),
 582                  log_file = joinpath(build_root, 'scons_config.log'),
 583                  custom_tests = {
 584         'CheckMember' : CheckMember,
 585         })
 586
 587 # Check if we should compile a 64 bit binary on Mac OS X/Darwin
 588 try:
 589     import platform
 590     uname = platform.uname()
 591     if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
 592         if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
 593             main.Append(CCFLAGS=['-arch', 'x86_64'])
 594             main.Append(CFLAGS=['-arch', 'x86_64'])
 595             main.Append(LINKFLAGS=['-arch', 'x86_64'])
 596             main.Append(ASFLAGS=['-arch', 'x86_64'])
 597 except:
 598     pass
 599
 600 # Recent versions of scons substitute a "Null" object for Configure()
 601 # when configuration isn't necessary, e.g., if the "--help" option is
 602 # present.  Unfortuantely this Null object always returns false,
 603 # breaking all our configuration checks.  We replace it with our own
 604 # more optimistic null object that returns True instead.
 605 if not conf:
 606     def NullCheck(*args, **kwargs):
 607         return True
 608
 609     class NullConf:
 610         def __init__(self, env):
 611             self.env = env
 612         def Finish(self):
 613             return self.env
 614         def __getattr__(self, mname):
 615             return NullCheck
 616
 617     conf = NullConf(main)
 618
 619 # Cache build files in the supplied directory.
 620 if main['M5_BUILD_CACHE']:
 621     print('Using build cache located at', main['M5_BUILD_CACHE'])
 622     CacheDir(main['M5_BUILD_CACHE'])
 623
 624 main['USE_PYTHON'] = not GetOption('without_python')
 625 if main['USE_PYTHON']:
 626     # Find Python include and library directories for embedding the
 627     # interpreter. We rely on python-config to resolve the appropriate
 628     # includes and linker flags. ParseConfig does not seem to understand
 629     # the more exotic linker flags such as -Xlinker and -export-dynamic so
 630     # we add them explicitly below. If you want to link in an alternate
 631     # version of python, see above for instructions on how to invoke
 632     # scons with the appropriate PATH set.
 633
 634     python_config = main.Detect(main['PYTHON_CONFIG'])
 635     if python_config is None:
 636         error("Can't find a suitable python-config, tried %s" % \
 637               main['PYTHON_CONFIG'])
 638
 639     print("Info: Using Python config: %s" % (python_config, ))
 640     py_includes = readCommand([python_config, '--includes'],
 641                               exception='').split()
 642     py_includes = list(filter(
 643         lambda s: match(r'.*\/include\/.*',s), py_includes))
 644     # Strip the -I from the include folders before adding them to the
 645     # CPPPATH
 646     py_includes = list(map(
 647         lambda s: s[2:] if s.startswith('-I') else s, py_includes))
 648     main.Append(CPPPATH=py_includes)
 649
 650     # Read the linker flags and split them into libraries and other link
 651     # flags. The libraries are added later through the call the CheckLib.
 652     # Note: starting in Python 3.8 the --embed flag is required to get the
 653     # -lpython3.8 linker flag
 654     retcode, cmd_stdout = readCommandWithReturn(
 655         [python_config, '--ldflags', '--embed'], exception='')
 656     if retcode != 0:
 657         # If --embed isn't detected then we're running python <3.8
 658         retcode, cmd_stdout = readCommandWithReturn(
 659             [python_config, '--ldflags'], exception='')
 660
 661     # Checking retcode again
 662     if retcode != 0:
 663         error("Failing on python-config --ldflags command")
 664
 665     py_ld_flags = cmd_stdout.split()
 666
 667     py_libs = []
 668     for lib in py_ld_flags:
 669          if not lib.startswith('-l'):
 670              main.Append(LINKFLAGS=[lib])
 671          else:
 672              lib = lib[2:]
 673              if lib not in py_libs:
 674                  py_libs.append(lib)
 675
 676     # verify that this stuff works
 677     if not conf.CheckHeader('Python.h', '<>'):
 678         error("Check failed for Python.h header in",
 679                 ' '.join(py_includes), "\n"
 680               "Two possible reasons:\n"
 681               "1. Python headers are not installed (You can install the "
 682               "package python-dev on Ubuntu and RedHat)\n"
 683               "2. SCons is using a wrong C compiler. This can happen if "
 684               "CC has the wrong value.\n"
 685               "CC = %s" % main['CC'])
 686
 687     for lib in py_libs:
 688         if not conf.CheckLib(lib):
 689             error("Can't find library %s required by python." % lib)
 690
 691 main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
 692 # Bare minimum environment that only includes python
 693 marshal_env = main.Clone()
 694 marshal_env.Append(CCFLAGS='$MARSHAL_CCFLAGS_EXTRA')
 695 marshal_env.Append(LINKFLAGS='$MARSHAL_LDFLAGS_EXTRA')
 696
 697 # On Solaris you need to use libsocket for socket ops
 698 if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
 699    if not conf.CheckLibWithHeader('socket', 'sys/socket.h',
 700                                   'C++', 'accept(0,0,0);'):
 701        error("Can't find library with socket calls (e.g. accept()).")
 702
 703 # Check for zlib.  If the check passes, libz will be automatically
 704 # added to the LIBS environment variable.
 705 if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
 706     error('Did not find needed zlib compression library '
 707           'and/or zlib.h header file.\n'
 708           'Please install zlib and try again.')
 709
 710 # If we have the protobuf compiler, also make sure we have the
 711 # development libraries. If the check passes, libprotobuf will be
 712 # automatically added to the LIBS environment variable. After
 713 # this, we can use the HAVE_PROTOBUF flag to determine if we have
 714 # got both protoc and libprotobuf available.
 715 main['HAVE_PROTOBUF'] = main['HAVE_PROTOC'] and \
 716     conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
 717                             'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
 718
 719 # Valgrind gets much less confused if you tell it when you're using
 720 # alternative stacks.
 721 main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
 722
 723 # If we have the compiler but not the library, print another warning.
 724 if main['HAVE_PROTOC'] and not main['HAVE_PROTOBUF']:
 725     warning('Did not find protocol buffer library and/or headers.\n'
 726             'Please install libprotobuf-dev for tracing support.')
 727
 728 # Check for librt.
 729 have_posix_clock = \
 730     conf.CheckLibWithHeader(None, 'time.h', 'C',
 731                             'clock_nanosleep(0,0,NULL,NULL);') or \
 732     conf.CheckLibWithHeader('rt', 'time.h', 'C',
 733                             'clock_nanosleep(0,0,NULL,NULL);')
 734
 735 have_posix_timers = \
 736     conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
 737                             'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
 738
 739 if not GetOption('without_tcmalloc'):
 740     if conf.CheckLib('tcmalloc'):
 741         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 742     elif conf.CheckLib('tcmalloc_minimal'):
 743         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 744     else:
 745         warning("You can get a 12% performance improvement by "
 746                 "installing tcmalloc (libgoogle-perftools-dev package "
 747                 "on Ubuntu or RedHat).")
 748
 749
 750 # Detect back trace implementations. The last implementation in the
 751 # list will be used by default.
 752 backtrace_impls = [ "none" ]
 753
 754 backtrace_checker = 'char temp;' + \
 755     ' backtrace_symbols_fd((void*)&temp, 0, 0);'
 756 if conf.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker):
 757     backtrace_impls.append("glibc")
 758 elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
 759                              backtrace_checker):
 760     # NetBSD and FreeBSD need libexecinfo.
 761     backtrace_impls.append("glibc")
 762     main.Append(LIBS=['execinfo'])
 763
 764 if backtrace_impls[-1] == "none":
 765     default_backtrace_impl = "none"
 766     warning("No suitable back trace implementation found.")
 767
 768 if not have_posix_clock:
 769     warning("Can't find library for POSIX clocks.")
 770
 771 # Check for <fenv.h> (C99 FP environment control)
 772 have_fenv = conf.CheckHeader('fenv.h', '<>')
 773 if not have_fenv:
 774     warning("Header file <fenv.h> not found.\n"
 775             "This host has no IEEE FP rounding mode control.")
 776
 777 # Check for <png.h> (libpng library needed if wanting to dump
 778 # frame buffer image in png format)
 779 have_png = conf.CheckHeader('png.h', '<>')
 780 if not have_png:
 781     warning("Header file <png.h> not found.\n"
 782             "This host has no libpng library.\n"
 783             "Disabling support for PNG framebuffers.")
 784
 785 # Check if we should enable KVM-based hardware virtualization. The API
 786 # we rely on exists since version 2.6.36 of the kernel, but somehow
 787 # the KVM_API_VERSION does not reflect the change. We test for one of
 788 # the types as a fall back.
 789 have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
 790 if not have_kvm:
 791     print("Info: Compatible header file <linux/kvm.h> not found, "
 792           "disabling KVM support.")
 793
 794 # Check if the TUN/TAP driver is available.
 795 have_tuntap = conf.CheckHeader('linux/if_tun.h', '<>')
 796 if not have_tuntap:
 797     print("Info: Compatible header file <linux/if_tun.h> not found.")
 798
 799 # x86 needs support for xsave. We test for the structure here since we
 800 # won't be able to run new tests by the time we know which ISA we're
 801 # targeting.
 802 have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
 803                                     '#include <linux/kvm.h>') != 0
 804
 805 # Check if the requested target ISA is compatible with the host
 806 def is_isa_kvm_compatible(isa):
 807     try:
 808         import platform
 809         host_isa = platform.machine()
 810     except:
 811         warning("Failed to determine host ISA.")
 812         return False
 813
 814     if not have_posix_timers:
 815         warning("Can not enable KVM, host seems to lack support "
 816                 "for POSIX timers")
 817         return False
 818
 819     if isa == "arm":
 820         return host_isa in ( "armv7l", "aarch64" )
 821     elif isa == "x86":
 822         if host_isa != "x86_64":
 823             return False
 824
 825         if not have_kvm_xsave:
 826             warning("KVM on x86 requires xsave support in kernel headers.")
 827             return False
 828
 829         return True
 830     else:
 831         return False
 832
 833
 834 # Check if the exclude_host attribute is available. We want this to
 835 # get accurate instruction counts in KVM.
 836 main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
 837     'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
 838
 839 def check_hdf5():
 840     return \
 841         conf.CheckLibWithHeader('hdf5', 'hdf5.h', 'C',
 842                                 'H5Fcreate("", 0, 0, 0);') and \
 843         conf.CheckLibWithHeader('hdf5_cpp', 'H5Cpp.h', 'C++',
 844                                 'H5::H5File("", 0);')
 845
 846 def check_hdf5_pkg(name):
 847     print("Checking for %s using pkg-config..." % name, end="")
 848     if not have_pkg_config:
 849         print(" pkg-config not found")
 850         return False
 851
 852     try:
 853         main.ParseConfig('pkg-config --cflags-only-I --libs-only-L %s' % name)
 854         print(" yes")
 855         return True
 856     except:
 857         print(" no")
 858         return False
 859
 860 # Check if there is a pkg-config configuration for hdf5. If we find
 861 # it, setup the environment to enable linking and header inclusion. We
 862 # don't actually try to include any headers or link with hdf5 at this
 863 # stage.
 864 if not check_hdf5_pkg('hdf5-serial'):
 865     check_hdf5_pkg('hdf5')
 866
 867 # Check if the HDF5 libraries can be found. This check respects the
 868 # include path and library path provided by pkg-config. We perform
 869 # this check even if there isn't a pkg-config configuration for hdf5
 870 # since some installations don't use pkg-config.
 871 have_hdf5 = check_hdf5()
 872 if not have_hdf5:
 873     print("Warning: Couldn't find any HDF5 C++ libraries. Disabling")
 874     print("         HDF5 support.")
 875
 876 ######################################################################
 877 #
 878 # Finish the configuration
 879 #
 880 main = conf.Finish()
 881
 882 ######################################################################
 883 #
 884 # Collect all non-global variables
 885 #
 886
 887 # Define the universe of supported ISAs
 888 all_isa_list = [ ]
 889 all_gpu_isa_list = [ ]
 890 Export('all_isa_list')
 891 Export('all_gpu_isa_list')
 892
 893 class CpuModel(object):
 894     '''The CpuModel class encapsulates everything the ISA parser needs to
 895     know about a particular CPU model.'''
 896
 897     # Dict of available CPU model objects.  Accessible as CpuModel.dict.
 898     dict = {}
 899
 900     # Constructor.  Automatically adds models to CpuModel.dict.
 901     def __init__(self, name, default=False):
 902         self.name = name           # name of model
 903
 904         # This cpu is enabled by default
 905         self.default = default
 906
 907         # Add self to dict
 908         if name in CpuModel.dict:
 909             raise AttributeError("CpuModel '%s' already registered" % name)
 910         CpuModel.dict[name] = self
 911
 912 Export('CpuModel')
 913
 914 # Sticky variables get saved in the variables file so they persist from
 915 # one invocation to the next (unless overridden, in which case the new
 916 # value becomes sticky).
 917 sticky_vars = Variables(args=ARGUMENTS)
 918 Export('sticky_vars')
 919
 920 # Sticky variables that should be exported
 921 export_vars = []
 922 Export('export_vars')
 923
 924 # For Ruby
 925 all_protocols = []
 926 Export('all_protocols')
 927 protocol_dirs = []
 928 Export('protocol_dirs')
 929 slicc_includes = []
 930 Export('slicc_includes')
 931
 932 # Walk the tree and execute all SConsopts scripts that wil add to the
 933 # above variables
 934 if GetOption('verbose'):
 935     print("Reading SConsopts")
 936 for bdir in [ base_dir ] + extras_dir_list:
 937     if not isdir(bdir):
 938         error("Directory '%s' does not exist." % bdir)
 939     for root, dirs, files in os.walk(bdir):
 940         if 'SConsopts' in files:
 941             if GetOption('verbose'):
 942                 print("Reading", joinpath(root, 'SConsopts'))
 943             SConscript(joinpath(root, 'SConsopts'))
 944
 945 all_isa_list.sort()
 946 all_gpu_isa_list.sort()
 947
 948 sticky_vars.AddVariables(
 949     EnumVariable('TARGET_ISA', 'Target ISA', 'null', all_isa_list),
 950     EnumVariable('TARGET_GPU_ISA', 'Target GPU ISA', 'gcn3', all_gpu_isa_list),
 951     ListVariable('CPU_MODELS', 'CPU models',
 952                  sorted(n for n,m in CpuModel.dict.items() if m.default),
 953                  sorted(CpuModel.dict.keys())),
 954     BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
 955                  False),
 956     BoolVariable('USE_SSE2',
 957                  'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
 958                  False),
 959     BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
 960     BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
 961     BoolVariable('USE_PNG',  'Enable support for PNG images', have_png),
 962     BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models',
 963                  have_kvm),
 964     BoolVariable('USE_TUNTAP',
 965                  'Enable using a tap device to bridge to the host network',
 966                  have_tuntap),
 967     BoolVariable('BUILD_GPU', 'Build the compute-GPU model', False),
 968     EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
 969                   all_protocols),
 970     EnumVariable('BACKTRACE_IMPL', 'Post-mortem dump implementation',
 971                  backtrace_impls[-1], backtrace_impls),
 972     ('NUMBER_BITS_PER_SET', 'Max elements in set (default 64)',
 973                  64),
 974     BoolVariable('USE_HDF5', 'Enable the HDF5 support', have_hdf5),
 975     )
 976
 977 # These variables get exported to #defines in config/*.hh (see src/SConscript).
 978 export_vars += ['USE_FENV', 'TARGET_ISA', 'TARGET_GPU_ISA',
 979                 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP', 'PROTOCOL',
 980                 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
 981                 'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG',
 982                 'NUMBER_BITS_PER_SET', 'USE_HDF5']
 983
 984 ###################################################
 985 #
 986 # Define a SCons builder for configuration flag headers.
 987 #
 988 ###################################################
 989
 990 # This function generates a config header file that #defines the
 991 # variable symbol to the current variable setting (0 or 1).  The source
 992 # operands are the name of the variable and a Value node containing the
 993 # value of the variable.
 994 def build_config_file(target, source, env):
 995     (variable, value) = [s.get_contents().decode('utf-8') for s in source]
 996     with open(str(target[0]), 'w') as f:
 997         print('#define', variable, value, file=f)
 998     return None
 999
1000 # Combine the two functions into a scons Action object.
1001 config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1002
1003 # The emitter munges the source & target node lists to reflect what
1004 # we're really doing.
1005 def config_emitter(target, source, env):
1006     # extract variable name from Builder arg
1007     variable = str(target[0])
1008     # True target is config header file
1009     target = joinpath('config', variable.lower() + '.hh')
1010     val = env[variable]
1011     if isinstance(val, bool):
1012         # Force value to 0/1
1013         val = int(val)
1014     elif isinstance(val, str):
1015         val = '"' + val + '"'
1016
1017     # Sources are variable name & value (packaged in SCons Value nodes)
1018     return ([target], [Value(variable), Value(val)])
1019
1020 config_builder = Builder(emitter = config_emitter, action = config_action)
1021
1022 main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1023
1024 ###################################################
1025 #
1026 # Builders for static and shared partially linked object files.
1027 #
1028 ###################################################
1029
1030 partial_static_builder = Builder(action=SCons.Defaults.LinkAction,
1031                                  src_suffix='$OBJSUFFIX',
1032                                  src_builder=['StaticObject', 'Object'],
1033                                  LINKFLAGS='$PLINKFLAGS',
1034                                  LIBS='')
1035
1036 def partial_shared_emitter(target, source, env):
1037     for tgt in target:
1038         tgt.attributes.shared = 1
1039     return (target, source)
1040 partial_shared_builder = Builder(action=SCons.Defaults.ShLinkAction,
1041                                  emitter=partial_shared_emitter,
1042                                  src_suffix='$SHOBJSUFFIX',
1043                                  src_builder='SharedObject',
1044                                  SHLINKFLAGS='$PSHLINKFLAGS',
1045                                  LIBS='')
1046
1047 main.Append(BUILDERS = { 'PartialShared' : partial_shared_builder,
1048                          'PartialStatic' : partial_static_builder })
1049
1050 def add_local_rpath(env, *targets):
1051     '''Set up an RPATH for a library which lives in the build directory.
1052
1053     The construction environment variable BIN_RPATH_PREFIX should be set to
1054     the relative path of the build directory starting from the location of the
1055     binary.'''
1056     for target in targets:
1057         target = env.Entry(target)
1058         if not isinstance(target, SCons.Node.FS.Dir):
1059             target = target.dir
1060         relpath = os.path.relpath(target.abspath, env['BUILDDIR'])
1061         components = [
1062             '\\$$ORIGIN',
1063             '${BIN_RPATH_PREFIX}',
1064             relpath
1065         ]
1066         env.Append(RPATH=[env.Literal(os.path.join(*components))])
1067
1068 if sys.platform != "darwin":
1069     main.Append(LINKFLAGS=Split('-z origin'))
1070
1071 main.AddMethod(add_local_rpath, 'AddLocalRPATH')
1072
1073 # builds in ext are shared across all configs in the build root.
1074 ext_dir = abspath(joinpath(str(main.root), 'ext'))
1075 ext_build_dirs = []
1076 for root, dirs, files in os.walk(ext_dir):
1077     if 'SConscript' in files:
1078         build_dir = os.path.relpath(root, ext_dir)
1079         ext_build_dirs.append(build_dir)
1080         main.SConscript(joinpath(root, 'SConscript'),
1081                         variant_dir=joinpath(build_root, build_dir))
1082
1083 gdb_xml_dir = joinpath(ext_dir, 'gdb-xml')
1084 Export('gdb_xml_dir')
1085
1086 ###################################################
1087 #
1088 # This builder and wrapper method are used to set up a directory with
1089 # switching headers. Those are headers which are in a generic location and
1090 # that include more specific headers from a directory chosen at build time
1091 # based on the current build settings.
1092 #
1093 ###################################################
1094
1095 def build_switching_header(target, source, env):
1096     path = str(target[0])
1097     subdir = str(source[0])
1098     dp, fp = os.path.split(path)
1099     dp = os.path.relpath(os.path.realpath(dp),
1100                          os.path.realpath(env['BUILDDIR']))
1101     with open(path, 'w') as hdr:
1102         print('#include "%s/%s/%s"' % (dp, subdir, fp), file=hdr)
1103
1104 switching_header_action = MakeAction(build_switching_header,
1105                                      Transform('GENERATE'))
1106
1107 switching_header_builder = Builder(action=switching_header_action,
1108                                    source_factory=Value,
1109                                    single_source=True)
1110
1111 main.Append(BUILDERS = { 'SwitchingHeader': switching_header_builder })
1112
1113 def switching_headers(self, headers, source):
1114     for header in headers:
1115         self.SwitchingHeader(header, source)
1116
1117 main.AddMethod(switching_headers, 'SwitchingHeaders')
1118
1119 ###################################################
1120 #
1121 # Define build environments for selected configurations.
1122 #
1123 ###################################################
1124
1125 for variant_path in variant_paths:
1126     if not GetOption('silent'):
1127         print("Building in", variant_path)
1128
1129     # Make a copy of the build-root environment to use for this config.
1130     env = main.Clone()
1131     env['BUILDDIR'] = variant_path
1132
1133     # variant_dir is the tail component of build path, and is used to
1134     # determine the build parameters (e.g., 'X86')
1135     (build_root, variant_dir) = splitpath(variant_path)
1136
1137     # Set env variables according to the build directory config.
1138     sticky_vars.files = []
1139     # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1140     # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1141     # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1142     current_vars_file = joinpath(build_root, 'variables', variant_dir)
1143     if isfile(current_vars_file):
1144         sticky_vars.files.append(current_vars_file)
1145         if not GetOption('silent'):
1146             print("Using saved variables file %s" % current_vars_file)
1147     elif variant_dir in ext_build_dirs:
1148         # Things in ext are built without a variant directory.
1149         continue
1150     else:
1151         # Build dir-specific variables file doesn't exist.
1152
1153         # Make sure the directory is there so we can create it later
1154         opt_dir = dirname(current_vars_file)
1155         if not isdir(opt_dir):
1156             mkdir(opt_dir)
1157
1158         # Get default build variables from source tree.  Variables are
1159         # normally determined by name of $VARIANT_DIR, but can be
1160         # overridden by '--default=' arg on command line.
1161         default = GetOption('default')
1162         opts_dir = joinpath(main.root.abspath, 'build_opts')
1163         if default:
1164             default_vars_files = [joinpath(build_root, 'variables', default),
1165                                   joinpath(opts_dir, default)]
1166         else:
1167             default_vars_files = [joinpath(opts_dir, variant_dir)]
1168         existing_files = list(filter(isfile, default_vars_files))
1169         if existing_files:
1170             default_vars_file = existing_files[0]
1171             sticky_vars.files.append(default_vars_file)
1172             print("Variables file %s not found,\n  using defaults in %s"
1173                   % (current_vars_file, default_vars_file))
1174         else:
1175             error("Cannot find variables file %s or default file(s) %s"
1176                   % (current_vars_file, ' or '.join(default_vars_files)))
1177             Exit(1)
1178
1179     # Apply current variable settings to env
1180     sticky_vars.Update(env)
1181
1182     Help('''
1183 Build variables for {dir}:
1184 {help}
1185 '''.format(dir=variant_dir, help=sticky_vars.GenerateHelpText(env)),
1186          append=True)
1187
1188     # Process variable settings.
1189
1190     if not have_fenv and env['USE_FENV']:
1191         warning("<fenv.h> not available; forcing USE_FENV to False in",
1192                 variant_dir + ".")
1193         env['USE_FENV'] = False
1194
1195     if not env['USE_FENV']:
1196         warning("No IEEE FP rounding mode control in", variant_dir + ".\n"
1197                 "FP results may deviate slightly from other platforms.")
1198
1199     if not have_png and env['USE_PNG']:
1200         warning("<png.h> not available; forcing USE_PNG to False in",
1201                 variant_dir + ".")
1202         env['USE_PNG'] = False
1203
1204     if env['USE_PNG']:
1205         env.Append(LIBS=['png'])
1206
1207     if env['EFENCE']:
1208         env.Append(LIBS=['efence'])
1209
1210     if env['USE_KVM']:
1211         if not have_kvm:
1212             warning("Can not enable KVM, host seems to lack KVM support")
1213             env['USE_KVM'] = False
1214         elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1215             print("Info: KVM support disabled due to unsupported host and "
1216                   "target ISA combination")
1217             env['USE_KVM'] = False
1218
1219     if env['USE_TUNTAP']:
1220         if not have_tuntap:
1221             warning("Can't connect EtherTap with a tap device.")
1222             env['USE_TUNTAP'] = False
1223
1224     if env['BUILD_GPU']:
1225         env.Append(CPPDEFINES=['BUILD_GPU'])
1226
1227     # Warn about missing optional functionality
1228     if env['USE_KVM']:
1229         if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1230             warning("perf_event headers lack support for the exclude_host "
1231                     "attribute. KVM instruction counts will be inaccurate.")
1232
1233     # Save sticky variable settings back to current variables file
1234     sticky_vars.Save(current_vars_file, env)
1235
1236     if env['USE_SSE2']:
1237         env.Append(CCFLAGS=['-msse2'])
1238
1239     env.Append(CCFLAGS='$CCFLAGS_EXTRA')
1240     env.Append(LINKFLAGS='$LDFLAGS_EXTRA')
1241
1242     # The src/SConscript file sets up the build rules in 'env' according
1243     # to the configured variables.  It returns a list of environments,
1244     # one for each variant build (debug, opt, etc.)
1245     SConscript('src/SConscript', variant_dir=variant_path,
1246                exports=['env', 'marshal_env'])
1247
1248 atexit.register(summarize_warnings)