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 help_texts = {
 103     "options" : "",
 104     "global_vars" : "",
 105     "local_vars" : ""
 106 }
 107
 108 Export("help_texts")
 109
 110
 111 # There's a bug in scons in that (1) by default, the help texts from
 112 # AddOption() are supposed to be displayed when you type 'scons -h'
 113 # and (2) you can override the help displayed by 'scons -h' using the
 114 # Help() function, but these two features are incompatible: once
 115 # you've overridden the help text using Help(), there's no way to get
 116 # at the help texts from AddOptions.  See:
 117 #     https://github.com/SCons/scons/issues/2356
 118 #     https://github.com/SCons/scons/issues/2611
 119 # This hack lets us extract the help text from AddOptions and
 120 # re-inject it via Help().  Ideally someday this bug will be fixed and
 121 # we can just use AddOption directly.
 122 def AddLocalOption(*args, **kwargs):
 123     col_width = 30
 124
 125     help = "  " + ", ".join(args)
 126     if "help" in kwargs:
 127         length = len(help)
 128         if length >= col_width:
 129             help += "\n" + " " * col_width
 130         else:
 131             help += " " * (col_width - length)
 132         help += kwargs["help"]
 133     help_texts["options"] += help + "\n"
 134
 135     AddOption(*args, **kwargs)
 136
 137 AddLocalOption('--colors', dest='use_colors', action='store_true',
 138                help="Add color to abbreviated scons output")
 139 AddLocalOption('--no-colors', dest='use_colors', action='store_false',
 140                help="Don't add color to abbreviated scons output")
 141 AddLocalOption('--with-cxx-config', action='store_true',
 142                help="Build with support for C++-based configuration")
 143 AddLocalOption('--default',
 144                help='Override which build_opts file to use for defaults')
 145 AddLocalOption('--ignore-style', action='store_true',
 146                help='Disable style checking hooks')
 147 AddLocalOption('--gold-linker', action='store_true',
 148                help='Use the gold linker')
 149 AddLocalOption('--no-lto', action='store_true',
 150                help='Disable Link-Time Optimization for fast')
 151 AddLocalOption('--force-lto', action='store_true',
 152                help='Use Link-Time Optimization instead of partial linking' +
 153                     ' when the compiler doesn\'t support using them together.')
 154 AddLocalOption('--verbose', action='store_true',
 155                help='Print full tool command lines')
 156 AddLocalOption('--without-python', action='store_true',
 157                help='Build without Python configuration support')
 158 AddLocalOption('--without-tcmalloc', action='store_true',
 159                help='Disable linking against tcmalloc')
 160 AddLocalOption('--with-ubsan', action='store_true',
 161                help='Build with Undefined Behavior Sanitizer if available')
 162 AddLocalOption('--with-asan', action='store_true',
 163                help='Build with Address Sanitizer if available')
 164 AddLocalOption('--with-systemc-tests', action='store_true',
 165                help='Build systemc tests')
 166
 167 from gem5_scons import Transform, error, warning, summarize_warnings
 168
 169 if GetOption('no_lto') and GetOption('force_lto'):
 170     error('--no-lto and --force-lto are mutually exclusive')
 171
 172 ########################################################################
 173 #
 174 # Set up the main build environment.
 175 #
 176 ########################################################################
 177
 178 main = Environment()
 179
 180 from gem5_scons.util import get_termcap
 181 termcap = get_termcap()
 182
 183 main_dict_keys = main.Dictionary().keys()
 184
 185 # Check that we have a C/C++ compiler
 186 if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
 187     error("No C++ compiler installed (package g++ on Ubuntu and RedHat)")
 188
 189 ###################################################
 190 #
 191 # Figure out which configurations to set up based on the path(s) of
 192 # the target(s).
 193 #
 194 ###################################################
 195
 196 # Find default configuration & binary.
 197 Default(environ.get('M5_DEFAULT_BINARY', 'build/ARM/gem5.debug'))
 198
 199 # helper function: find last occurrence of element in list
 200 def rfind(l, elt, offs = -1):
 201     for i in range(len(l)+offs, 0, -1):
 202         if l[i] == elt:
 203             return i
 204     raise ValueError("element not found")
 205
 206 # Take a list of paths (or SCons Nodes) and return a list with all
 207 # paths made absolute and ~-expanded.  Paths will be interpreted
 208 # relative to the launch directory unless a different root is provided
 209 def makePathListAbsolute(path_list, root=GetLaunchDir()):
 210     return [abspath(joinpath(root, expanduser(str(p))))
 211             for p in path_list]
 212
 213 # Each target must have 'build' in the interior of the path; the
 214 # directory below this will determine the build parameters.  For
 215 # example, for target 'foo/bar/build/X86/arch/x86/blah.do' we
 216 # recognize that X86 specifies the configuration because it
 217 # follow 'build' in the build path.
 218
 219 # The funky assignment to "[:]" is needed to replace the list contents
 220 # in place rather than reassign the symbol to a new list, which
 221 # doesn't work (obviously!).
 222 BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
 223
 224 # Generate a list of the unique build roots and configs that the
 225 # collected targets reference.
 226 variant_paths = []
 227 build_root = None
 228 for t in BUILD_TARGETS:
 229     path_dirs = t.split('/')
 230     try:
 231         build_top = rfind(path_dirs, 'build', -2)
 232     except:
 233         error("No non-leaf 'build' dir found on target path.", t)
 234     this_build_root = joinpath('/',*path_dirs[:build_top+1])
 235     if not build_root:
 236         build_root = this_build_root
 237     else:
 238         if this_build_root != build_root:
 239             error("build targets not under same build root\n"
 240                   "  %s\n  %s" % (build_root, this_build_root))
 241     variant_path = joinpath('/',*path_dirs[:build_top+2])
 242     if variant_path not in variant_paths:
 243         variant_paths.append(variant_path)
 244
 245 # Make sure build_root exists (might not if this is the first build there)
 246 if not isdir(build_root):
 247     mkdir(build_root)
 248 main['BUILDROOT'] = build_root
 249
 250 Export('main')
 251
 252 main.SConsignFile(joinpath(build_root, "sconsign"))
 253
 254 # Default duplicate option is to use hard links, but this messes up
 255 # when you use emacs to edit a file in the target dir, as emacs moves
 256 # file to file~ then copies to file, breaking the link.  Symbolic
 257 # (soft) links work better.
 258 main.SetOption('duplicate', 'soft-copy')
 259
 260 #
 261 # Set up global sticky variables... these are common to an entire build
 262 # tree (not specific to a particular build like X86)
 263 #
 264
 265 global_vars_file = joinpath(build_root, 'variables.global')
 266
 267 global_vars = Variables(global_vars_file, args=ARGUMENTS)
 268
 269 global_vars.AddVariables(
 270     ('CC', 'C compiler', environ.get('CC', main['CC'])),
 271     ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
 272     ('CCFLAGS_EXTRA', 'Extra C and C++ compiler flags', ''),
 273     ('LDFLAGS_EXTRA', 'Extra linker flags', ''),
 274     ('MARSHAL_CCFLAGS_EXTRA', 'Extra C and C++ marshal compiler flags', ''),
 275     ('MARSHAL_LDFLAGS_EXTRA', 'Extra marshal linker flags', ''),
 276     ('PYTHON_CONFIG', 'Python config binary to use',
 277      [ 'python2.7-config', 'python-config', 'python3-config' ]),
 278     ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
 279     ('BATCH', 'Use batch pool for build and tests', False),
 280     ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
 281     ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
 282     ('EXTRAS', 'Add extra directories to the compilation', '')
 283     )
 284
 285 # Update main environment with values from ARGUMENTS & global_vars_file
 286 global_vars.Update(main)
 287 help_texts["global_vars"] += global_vars.GenerateHelpText(main)
 288
 289 # Save sticky variable settings back to current variables file
 290 global_vars.Save(global_vars_file, main)
 291
 292 # Parse EXTRAS variable to build list of all directories where we're
 293 # look for sources etc.  This list is exported as extras_dir_list.
 294 base_dir = main.srcdir.abspath
 295 if main['EXTRAS']:
 296     extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
 297 else:
 298     extras_dir_list = []
 299
 300 Export('base_dir')
 301 Export('extras_dir_list')
 302
 303 # the ext directory should be on the #includes path
 304 main.Append(CPPPATH=[Dir('ext')])
 305
 306 # Add shared top-level headers
 307 main.Prepend(CPPPATH=Dir('include'))
 308
 309 if GetOption('verbose'):
 310     def MakeAction(action, string, *args, **kwargs):
 311         return Action(action, *args, **kwargs)
 312 else:
 313     MakeAction = Action
 314     main['CCCOMSTR']        = Transform("CC")
 315     main['CXXCOMSTR']       = Transform("CXX")
 316     main['ASCOMSTR']        = Transform("AS")
 317     main['ARCOMSTR']        = Transform("AR", 0)
 318     main['LINKCOMSTR']      = Transform("LINK", 0)
 319     main['SHLINKCOMSTR']    = Transform("SHLINK", 0)
 320     main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
 321     main['M4COMSTR']        = Transform("M4")
 322     main['SHCCCOMSTR']      = Transform("SHCC")
 323     main['SHCXXCOMSTR']     = Transform("SHCXX")
 324 Export('MakeAction')
 325
 326 # Initialize the Link-Time Optimization (LTO) flags
 327 main['LTO_CCFLAGS'] = []
 328 main['LTO_LDFLAGS'] = []
 329
 330 # According to the readme, tcmalloc works best if the compiler doesn't
 331 # assume that we're using the builtin malloc and friends. These flags
 332 # are compiler-specific, so we need to set them after we detect which
 333 # compiler we're using.
 334 main['TCMALLOC_CCFLAGS'] = []
 335
 336 CXX_version = readCommand([main['CXX'],'--version'], exception=False)
 337 CXX_V = readCommand([main['CXX'],'-V'], exception=False)
 338
 339 main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
 340 main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
 341 if main['GCC'] + main['CLANG'] > 1:
 342     error('Two compilers enabled at once?')
 343
 344 # Set up default C++ compiler flags
 345 if main['GCC'] or main['CLANG']:
 346     # As gcc and clang share many flags, do the common parts here
 347     main.Append(CCFLAGS=['-pipe'])
 348     main.Append(CCFLAGS=['-fno-strict-aliasing'])
 349     # Enable -Wall and -Wextra and then disable the few warnings that
 350     # we consistently violate
 351     main.Append(CCFLAGS=['-Wall', '-Wundef', '-Wextra',
 352                          '-Wno-sign-compare', '-Wno-unused-parameter'])
 353     # We always compile using C++11
 354     main.Append(CXXFLAGS=['-std=c++11'])
 355     if sys.platform.startswith('freebsd'):
 356         main.Append(CCFLAGS=['-I/usr/local/include'])
 357         main.Append(CXXFLAGS=['-I/usr/local/include'])
 358
 359     # On Mac OS X/Darwin the default linker doesn't support the
 360     # option --as-needed
 361     if sys.platform != "darwin":
 362         main.Append(LINKFLAGS='-Wl,--as-needed')
 363     main['FILTER_PSHLINKFLAGS'] = lambda x: str(x).replace(' -shared', '')
 364     main['PSHLINKFLAGS'] = main.subst('${FILTER_PSHLINKFLAGS(SHLINKFLAGS)}')
 365     if GetOption('gold_linker'):
 366         main.Append(LINKFLAGS='-fuse-ld=gold')
 367     main['PLINKFLAGS'] = main.get('LINKFLAGS')
 368     shared_partial_flags = ['-r', '-nostdlib']
 369     main.Append(PSHLINKFLAGS=shared_partial_flags)
 370     main.Append(PLINKFLAGS=shared_partial_flags)
 371
 372     # Treat warnings as errors but white list some warnings that we
 373     # want to allow (e.g., deprecation warnings).
 374     main.Append(CCFLAGS=['-Werror',
 375                          '-Wno-error=deprecated-declarations',
 376                          '-Wno-error=deprecated',
 377                         ])
 378 else:
 379     error('\n'.join((
 380           "Don't know what compiler options to use for your compiler.",
 381           "compiler: " + main['CXX'],
 382           "version: " + CXX_version.replace('\n', '<nl>') if
 383                 CXX_version else 'COMMAND NOT FOUND!',
 384           "If you're trying to use a compiler other than GCC",
 385           "or clang, there appears to be something wrong with your",
 386           "environment.",
 387           "",
 388           "If you are trying to use a compiler other than those listed",
 389           "above you will need to ease fix SConstruct and ",
 390           "src/SConscript to support that compiler.")))
 391
 392 if main['GCC']:
 393     # Check for a supported version of gcc. >= 4.8 is chosen for its
 394     # level of c++11 support. See
 395     # http://gcc.gnu.org/projects/cxx0x.html for details.
 396     gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
 397     if compareVersions(gcc_version, "4.8") < 0:
 398         error('gcc version 4.8 or newer required.\n'
 399               'Installed version:', gcc_version)
 400         Exit(1)
 401
 402     main['GCC_VERSION'] = gcc_version
 403
 404     if compareVersions(gcc_version, '4.9') >= 0:
 405         # Incremental linking with LTO is currently broken in gcc versions
 406         # 4.9 and above. A version where everything works completely hasn't
 407         # yet been identified.
 408         #
 409         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548
 410         main['BROKEN_INCREMENTAL_LTO'] = True
 411     if compareVersions(gcc_version, '6.0') >= 0:
 412         # gcc versions 6.0 and greater accept an -flinker-output flag which
 413         # selects what type of output the linker should generate. This is
 414         # necessary for incremental lto to work, but is also broken in
 415         # current versions of gcc. It may not be necessary in future
 416         # versions. We add it here since it might be, and as a reminder that
 417         # it exists. It's excluded if lto is being forced.
 418         #
 419         # https://gcc.gnu.org/gcc-6/changes.html
 420         # https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03161.html
 421         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69866
 422         if not GetOption('force_lto'):
 423             main.Append(PSHLINKFLAGS='-flinker-output=rel')
 424             main.Append(PLINKFLAGS='-flinker-output=rel')
 425
 426     disable_lto = GetOption('no_lto')
 427     if not disable_lto and main.get('BROKEN_INCREMENTAL_LTO', False) and \
 428             not GetOption('force_lto'):
 429         warning('Your compiler doesn\'t support incremental linking and lto '
 430                 'at the same time, so lto is being disabled. To force lto on '
 431                 'anyway, use the --force-lto option. That will disable '
 432                 'partial linking.')
 433         disable_lto = True
 434
 435     # Add the appropriate Link-Time Optimization (LTO) flags
 436     # unless LTO is explicitly turned off. Note that these flags
 437     # are only used by the fast target.
 438     if not disable_lto:
 439         # Pass the LTO flag when compiling to produce GIMPLE
 440         # output, we merely create the flags here and only append
 441         # them later
 442         main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 443
 444         # Use the same amount of jobs for LTO as we are running
 445         # scons with
 446         main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 447
 448     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
 449                                   '-fno-builtin-realloc', '-fno-builtin-free'])
 450
 451 elif main['CLANG']:
 452     # Check for a supported version of clang, >= 3.1 is needed to
 453     # support similar features as gcc 4.8. See
 454     # http://clang.llvm.org/cxx_status.html for details
 455     clang_version_re = re.compile(".* version (\d+\.\d+)")
 456     clang_version_match = clang_version_re.search(CXX_version)
 457     if (clang_version_match):
 458         clang_version = clang_version_match.groups()[0]
 459         if compareVersions(clang_version, "3.1") < 0:
 460             error('clang version 3.1 or newer required.\n'
 461                   'Installed version:', clang_version)
 462     else:
 463         error('Unable to determine clang version.')
 464
 465     # clang has a few additional warnings that we disable, extraneous
 466     # parantheses are allowed due to Ruby's printing of the AST,
 467     # finally self assignments are allowed as the generated CPU code
 468     # is relying on this
 469     main.Append(CCFLAGS=['-Wno-parentheses',
 470                          '-Wno-self-assign',
 471                          # Some versions of libstdc++ (4.8?) seem to
 472                          # use struct hash and class hash
 473                          # interchangeably.
 474                          '-Wno-mismatched-tags',
 475                          ])
 476     if compareVersions(clang_version, "10.0") >= 0:
 477         main.Append(CCFLAGS=['-Wno-c99-designator'])
 478
 479     if compareVersions(clang_version, "8.0") >= 0:
 480         main.Append(CCFLAGS=['-Wno-defaulted-function-deleted'])
 481
 482     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
 483
 484     # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
 485     # opposed to libstdc++, as the later is dated.
 486     if sys.platform == "darwin":
 487         main.Append(CXXFLAGS=['-stdlib=libc++'])
 488         main.Append(LIBS=['c++'])
 489
 490     # On FreeBSD we need libthr.
 491     if sys.platform.startswith('freebsd'):
 492         main.Append(LIBS=['thr'])
 493
 494 # Add sanitizers flags
 495 sanitizers=[]
 496 if GetOption('with_ubsan'):
 497     # Only gcc >= 4.9 supports UBSan, so check both the version
 498     # and the command-line option before adding the compiler and
 499     # linker flags.
 500     if not main['GCC'] or compareVersions(main['GCC_VERSION'], '4.9') >= 0:
 501         sanitizers.append('undefined')
 502 if GetOption('with_asan'):
 503     # Available for gcc >= 4.8 or llvm >= 3.1 both a requirement
 504     # by the build system
 505     sanitizers.append('address')
 506     suppressions_file = Dir('util').File('lsan-suppressions').get_abspath()
 507     suppressions_opt = 'suppressions=%s' % suppressions_file
 508     main['ENV']['LSAN_OPTIONS'] = ':'.join([suppressions_opt,
 509                                             'print_suppressions=0'])
 510     print()
 511     warning('To suppress false positive leaks, set the LSAN_OPTIONS '
 512             'environment variable to "%s" when running gem5' %
 513             suppressions_opt)
 514     warning('LSAN_OPTIONS=suppressions=%s' % suppressions_opt)
 515     print()
 516 if sanitizers:
 517     sanitizers = ','.join(sanitizers)
 518     if main['GCC'] or main['CLANG']:
 519         main.Append(CCFLAGS=['-fsanitize=%s' % sanitizers,
 520                              '-fno-omit-frame-pointer'],
 521                     LINKFLAGS='-fsanitize=%s' % sanitizers)
 522     else:
 523         warning("Don't know how to enable %s sanitizer(s) for your "
 524                 "compiler." % sanitizers)
 525
 526 # Set up common yacc/bison flags (needed for Ruby)
 527 main['YACCFLAGS'] = '-d'
 528 main['YACCHXXFILESUFFIX'] = '.hh'
 529
 530 # Do this after we save setting back, or else we'll tack on an
 531 # extra 'qdo' every time we run scons.
 532 if main['BATCH']:
 533     main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
 534     main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
 535     main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
 536     main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
 537     main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
 538
 539 if sys.platform == 'cygwin':
 540     # cygwin has some header file issues...
 541     main.Append(CCFLAGS=["-Wno-uninitialized"])
 542
 543
 544 have_pkg_config = readCommand(['pkg-config', '--version'], exception='')
 545
 546 # Check for the protobuf compiler
 547 try:
 548     main['HAVE_PROTOC'] = True
 549     protoc_version = readCommand([main['PROTOC'], '--version']).split()
 550
 551     # First two words should be "libprotoc x.y.z"
 552     if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
 553         warning('Protocol buffer compiler (protoc) not found.\n'
 554                 'Please install protobuf-compiler for tracing support.')
 555         main['HAVE_PROTOC'] = False
 556     else:
 557         # Based on the availability of the compress stream wrappers,
 558         # require 2.1.0
 559         min_protoc_version = '2.1.0'
 560         if compareVersions(protoc_version[1], min_protoc_version) < 0:
 561             warning('protoc version', min_protoc_version,
 562                     'or newer required.\n'
 563                     'Installed version:', protoc_version[1])
 564             main['HAVE_PROTOC'] = False
 565         else:
 566             # Attempt to determine the appropriate include path and
 567             # library path using pkg-config, that means we also need to
 568             # check for pkg-config. Note that it is possible to use
 569             # protobuf without the involvement of pkg-config. Later on we
 570             # check go a library config check and at that point the test
 571             # will fail if libprotobuf cannot be found.
 572             if have_pkg_config:
 573                 try:
 574                     # Attempt to establish what linking flags to add for
 575                     # protobuf
 576                     # using pkg-config
 577                     main.ParseConfig(
 578                             'pkg-config --cflags --libs-only-L protobuf')
 579                 except:
 580                     warning('pkg-config could not get protobuf flags.')
 581 except Exception as e:
 582     warning('While checking protoc version:', str(e))
 583     main['HAVE_PROTOC'] = False
 584
 585 # Check for 'timeout' from GNU coreutils. If present, regressions will
 586 # be run with a time limit. We require version 8.13 since we rely on
 587 # support for the '--foreground' option.
 588 if sys.platform.startswith('freebsd'):
 589     timeout_lines = readCommand(['gtimeout', '--version'],
 590                                 exception='').splitlines()
 591 else:
 592     timeout_lines = readCommand(['timeout', '--version'],
 593                                 exception='').splitlines()
 594 # Get the first line and tokenize it
 595 timeout_version = timeout_lines[0].split() if timeout_lines else []
 596 main['TIMEOUT'] =  timeout_version and \
 597     compareVersions(timeout_version[-1], '8.13') >= 0
 598
 599 # Add a custom Check function to test for structure members.
 600 def CheckMember(context, include, decl, member, include_quotes="<>"):
 601     context.Message("Checking for member %s in %s..." %
 602                     (member, decl))
 603     text = """
 604 #include %(header)s
 605 int main(){
 606   %(decl)s test;
 607   (void)test.%(member)s;
 608   return 0;
 609 };
 610 """ % { "header" : include_quotes[0] + include + include_quotes[1],
 611         "decl" : decl,
 612         "member" : member,
 613         }
 614
 615     ret = context.TryCompile(text, extension=".cc")
 616     context.Result(ret)
 617     return ret
 618
 619 # Platform-specific configuration.  Note again that we assume that all
 620 # builds under a given build root run on the same host platform.
 621 conf = Configure(main,
 622                  conf_dir = joinpath(build_root, '.scons_config'),
 623                  log_file = joinpath(build_root, 'scons_config.log'),
 624                  custom_tests = {
 625         'CheckMember' : CheckMember,
 626         })
 627
 628 # Check if we should compile a 64 bit binary on Mac OS X/Darwin
 629 try:
 630     import platform
 631     uname = platform.uname()
 632     if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
 633         if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
 634             main.Append(CCFLAGS=['-arch', 'x86_64'])
 635             main.Append(CFLAGS=['-arch', 'x86_64'])
 636             main.Append(LINKFLAGS=['-arch', 'x86_64'])
 637             main.Append(ASFLAGS=['-arch', 'x86_64'])
 638 except:
 639     pass
 640
 641 # Recent versions of scons substitute a "Null" object for Configure()
 642 # when configuration isn't necessary, e.g., if the "--help" option is
 643 # present.  Unfortuantely this Null object always returns false,
 644 # breaking all our configuration checks.  We replace it with our own
 645 # more optimistic null object that returns True instead.
 646 if not conf:
 647     def NullCheck(*args, **kwargs):
 648         return True
 649
 650     class NullConf:
 651         def __init__(self, env):
 652             self.env = env
 653         def Finish(self):
 654             return self.env
 655         def __getattr__(self, mname):
 656             return NullCheck
 657
 658     conf = NullConf(main)
 659
 660 # Cache build files in the supplied directory.
 661 if main['M5_BUILD_CACHE']:
 662     print('Using build cache located at', main['M5_BUILD_CACHE'])
 663     CacheDir(main['M5_BUILD_CACHE'])
 664
 665 main['USE_PYTHON'] = not GetOption('without_python')
 666 if main['USE_PYTHON']:
 667     # Find Python include and library directories for embedding the
 668     # interpreter. We rely on python-config to resolve the appropriate
 669     # includes and linker flags. ParseConfig does not seem to understand
 670     # the more exotic linker flags such as -Xlinker and -export-dynamic so
 671     # we add them explicitly below. If you want to link in an alternate
 672     # version of python, see above for instructions on how to invoke
 673     # scons with the appropriate PATH set.
 674
 675     python_config = main.Detect(main['PYTHON_CONFIG'])
 676     if python_config is None:
 677         error("Can't find a suitable python-config, tried %s" % \
 678               main['PYTHON_CONFIG'])
 679
 680     print("Info: Using Python config: %s" % (python_config, ))
 681     py_includes = readCommand([python_config, '--includes'],
 682                               exception='').split()
 683     py_includes = list(filter(
 684         lambda s: match(r'.*\/include\/.*',s), py_includes))
 685     # Strip the -I from the include folders before adding them to the
 686     # CPPPATH
 687     py_includes = list(map(
 688         lambda s: s[2:] if s.startswith('-I') else s, py_includes))
 689     main.Append(CPPPATH=py_includes)
 690
 691     # Read the linker flags and split them into libraries and other link
 692     # flags. The libraries are added later through the call the CheckLib.
 693     # Note: starting in Python 3.8 the --embed flag is required to get the
 694     # -lpython3.8 linker flag
 695     retcode, cmd_stdout = readCommandWithReturn(
 696         [python_config, '--ldflags', '--embed'], exception='')
 697     if retcode != 0:
 698         # If --embed isn't detected then we're running python <3.8
 699         retcode, cmd_stdout = readCommandWithReturn(
 700             [python_config, '--ldflags'], exception='')
 701
 702     # Checking retcode again
 703     if retcode != 0:
 704         error("Failing on python-config --ldflags command")
 705
 706     py_ld_flags = cmd_stdout.split()
 707
 708     py_libs = []
 709     for lib in py_ld_flags:
 710          if not lib.startswith('-l'):
 711              main.Append(LINKFLAGS=[lib])
 712          else:
 713              lib = lib[2:]
 714              if lib not in py_libs:
 715                  py_libs.append(lib)
 716
 717     # verify that this stuff works
 718     if not conf.CheckHeader('Python.h', '<>'):
 719         error("Check failed for Python.h header in",
 720                 ' '.join(py_includes), "\n"
 721               "Two possible reasons:\n"
 722               "1. Python headers are not installed (You can install the "
 723               "package python-dev on Ubuntu and RedHat)\n"
 724               "2. SCons is using a wrong C compiler. This can happen if "
 725               "CC has the wrong value.\n"
 726               "CC = %s" % main['CC'])
 727
 728     for lib in py_libs:
 729         if not conf.CheckLib(lib):
 730             error("Can't find library %s required by python." % lib)
 731
 732 main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
 733 # Bare minimum environment that only includes python
 734 marshal_env = main.Clone()
 735 marshal_env.Append(CCFLAGS='$MARSHAL_CCFLAGS_EXTRA')
 736 marshal_env.Append(LINKFLAGS='$MARSHAL_LDFLAGS_EXTRA')
 737
 738 # On Solaris you need to use libsocket for socket ops
 739 if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
 740    if not conf.CheckLibWithHeader('socket', 'sys/socket.h',
 741                                   'C++', 'accept(0,0,0);'):
 742        error("Can't find library with socket calls (e.g. accept()).")
 743
 744 # Check for zlib.  If the check passes, libz will be automatically
 745 # added to the LIBS environment variable.
 746 if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
 747     error('Did not find needed zlib compression library '
 748           'and/or zlib.h header file.\n'
 749           'Please install zlib and try again.')
 750
 751 if not conf.CheckLibWithHeader('elf', 'gelf.h', 'C++',
 752                                'elf_version(EV_CURRENT);'):
 753     error('Did not find ELF access library libelf')
 754
 755 # If we have the protobuf compiler, also make sure we have the
 756 # development libraries. If the check passes, libprotobuf will be
 757 # automatically added to the LIBS environment variable. After
 758 # this, we can use the HAVE_PROTOBUF flag to determine if we have
 759 # got both protoc and libprotobuf available.
 760 main['HAVE_PROTOBUF'] = main['HAVE_PROTOC'] and \
 761     conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
 762                             'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
 763
 764 # Valgrind gets much less confused if you tell it when you're using
 765 # alternative stacks.
 766 main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
 767
 768 # If we have the compiler but not the library, print another warning.
 769 if main['HAVE_PROTOC'] and not main['HAVE_PROTOBUF']:
 770     warning('Did not find protocol buffer library and/or headers.\n'
 771             'Please install libprotobuf-dev for tracing support.')
 772
 773 # Check for librt.
 774 have_posix_clock = \
 775     conf.CheckLibWithHeader(None, 'time.h', 'C',
 776                             'clock_nanosleep(0,0,NULL,NULL);') or \
 777     conf.CheckLibWithHeader('rt', 'time.h', 'C',
 778                             'clock_nanosleep(0,0,NULL,NULL);')
 779
 780 have_posix_timers = \
 781     conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
 782                             'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
 783
 784 if not GetOption('without_tcmalloc'):
 785     if conf.CheckLib('tcmalloc'):
 786         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 787     elif conf.CheckLib('tcmalloc_minimal'):
 788         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 789     else:
 790         warning("You can get a 12% performance improvement by "
 791                 "installing tcmalloc (libgoogle-perftools-dev package "
 792                 "on Ubuntu or RedHat).")
 793
 794
 795 # Detect back trace implementations. The last implementation in the
 796 # list will be used by default.
 797 backtrace_impls = [ "none" ]
 798
 799 backtrace_checker = 'char temp;' + \
 800     ' backtrace_symbols_fd((void*)&temp, 0, 0);'
 801 if conf.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker):
 802     backtrace_impls.append("glibc")
 803 elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
 804                              backtrace_checker):
 805     # NetBSD and FreeBSD need libexecinfo.
 806     backtrace_impls.append("glibc")
 807     main.Append(LIBS=['execinfo'])
 808
 809 if backtrace_impls[-1] == "none":
 810     default_backtrace_impl = "none"
 811     warning("No suitable back trace implementation found.")
 812
 813 if not have_posix_clock:
 814     warning("Can't find library for POSIX clocks.")
 815
 816 # Check for <fenv.h> (C99 FP environment control)
 817 have_fenv = conf.CheckHeader('fenv.h', '<>')
 818 if not have_fenv:
 819     warning("Header file <fenv.h> not found.\n"
 820             "This host has no IEEE FP rounding mode control.")
 821
 822 # Check for <png.h> (libpng library needed if wanting to dump
 823 # frame buffer image in png format)
 824 have_png = conf.CheckHeader('png.h', '<>')
 825 if not have_png:
 826     warning("Header file <png.h> not found.\n"
 827             "This host has no libpng library.\n"
 828             "Disabling support for PNG framebuffers.")
 829
 830 # Check if we should enable KVM-based hardware virtualization. The API
 831 # we rely on exists since version 2.6.36 of the kernel, but somehow
 832 # the KVM_API_VERSION does not reflect the change. We test for one of
 833 # the types as a fall back.
 834 have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
 835 if not have_kvm:
 836     print("Info: Compatible header file <linux/kvm.h> not found, "
 837           "disabling KVM support.")
 838
 839 # Check if the TUN/TAP driver is available.
 840 have_tuntap = conf.CheckHeader('linux/if_tun.h', '<>')
 841 if not have_tuntap:
 842     print("Info: Compatible header file <linux/if_tun.h> not found.")
 843
 844 # x86 needs support for xsave. We test for the structure here since we
 845 # won't be able to run new tests by the time we know which ISA we're
 846 # targeting.
 847 have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
 848                                     '#include <linux/kvm.h>') != 0
 849
 850 # Check if the requested target ISA is compatible with the host
 851 def is_isa_kvm_compatible(isa):
 852     try:
 853         import platform
 854         host_isa = platform.machine()
 855     except:
 856         warning("Failed to determine host ISA.")
 857         return False
 858
 859     if not have_posix_timers:
 860         warning("Can not enable KVM, host seems to lack support "
 861                 "for POSIX timers")
 862         return False
 863
 864     if isa == "arm":
 865         return host_isa in ( "armv7l", "aarch64" )
 866     elif isa == "x86":
 867         if host_isa != "x86_64":
 868             return False
 869
 870         if not have_kvm_xsave:
 871             warning("KVM on x86 requires xsave support in kernel headers.")
 872             return False
 873
 874         return True
 875     else:
 876         return False
 877
 878
 879 # Check if the exclude_host attribute is available. We want this to
 880 # get accurate instruction counts in KVM.
 881 main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
 882     'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
 883
 884 def check_hdf5():
 885     return \
 886         conf.CheckLibWithHeader('hdf5', 'hdf5.h', 'C',
 887                                 'H5Fcreate("", 0, 0, 0);') and \
 888         conf.CheckLibWithHeader('hdf5_cpp', 'H5Cpp.h', 'C++',
 889                                 'H5::H5File("", 0);')
 890
 891 def check_hdf5_pkg(name):
 892     print("Checking for %s using pkg-config..." % name, end="")
 893     if not have_pkg_config:
 894         print(" pkg-config not found")
 895         return False
 896
 897     try:
 898         main.ParseConfig('pkg-config --cflags-only-I --libs-only-L %s' % name)
 899         print(" yes")
 900         return True
 901     except:
 902         print(" no")
 903         return False
 904
 905 # Check if there is a pkg-config configuration for hdf5. If we find
 906 # it, setup the environment to enable linking and header inclusion. We
 907 # don't actually try to include any headers or link with hdf5 at this
 908 # stage.
 909 if not check_hdf5_pkg('hdf5-serial'):
 910     check_hdf5_pkg('hdf5')
 911
 912 # Check if the HDF5 libraries can be found. This check respects the
 913 # include path and library path provided by pkg-config. We perform
 914 # this check even if there isn't a pkg-config configuration for hdf5
 915 # since some installations don't use pkg-config.
 916 have_hdf5 = check_hdf5()
 917 if not have_hdf5:
 918     print("Warning: Couldn't find any HDF5 C++ libraries. Disabling")
 919     print("         HDF5 support.")
 920
 921 ######################################################################
 922 #
 923 # Finish the configuration
 924 #
 925 main = conf.Finish()
 926
 927 ######################################################################
 928 #
 929 # Collect all non-global variables
 930 #
 931
 932 # Define the universe of supported ISAs
 933 all_isa_list = [ ]
 934 all_gpu_isa_list = [ ]
 935 Export('all_isa_list')
 936 Export('all_gpu_isa_list')
 937
 938 class CpuModel(object):
 939     '''The CpuModel class encapsulates everything the ISA parser needs to
 940     know about a particular CPU model.'''
 941
 942     # Dict of available CPU model objects.  Accessible as CpuModel.dict.
 943     dict = {}
 944
 945     # Constructor.  Automatically adds models to CpuModel.dict.
 946     def __init__(self, name, default=False):
 947         self.name = name           # name of model
 948
 949         # This cpu is enabled by default
 950         self.default = default
 951
 952         # Add self to dict
 953         if name in CpuModel.dict:
 954             raise AttributeError("CpuModel '%s' already registered" % name)
 955         CpuModel.dict[name] = self
 956
 957 Export('CpuModel')
 958
 959 # Sticky variables get saved in the variables file so they persist from
 960 # one invocation to the next (unless overridden, in which case the new
 961 # value becomes sticky).
 962 sticky_vars = Variables(args=ARGUMENTS)
 963 Export('sticky_vars')
 964
 965 # Sticky variables that should be exported
 966 export_vars = []
 967 Export('export_vars')
 968
 969 # For Ruby
 970 all_protocols = []
 971 Export('all_protocols')
 972 protocol_dirs = []
 973 Export('protocol_dirs')
 974 slicc_includes = []
 975 Export('slicc_includes')
 976
 977 # Walk the tree and execute all SConsopts scripts that wil add to the
 978 # above variables
 979 if GetOption('verbose'):
 980     print("Reading SConsopts")
 981 for bdir in [ base_dir ] + extras_dir_list:
 982     if not isdir(bdir):
 983         error("Directory '%s' does not exist." % bdir)
 984     for root, dirs, files in os.walk(bdir):
 985         if 'SConsopts' in files:
 986             if GetOption('verbose'):
 987                 print("Reading", joinpath(root, 'SConsopts'))
 988             SConscript(joinpath(root, 'SConsopts'))
 989
 990 all_isa_list.sort()
 991 all_gpu_isa_list.sort()
 992
 993 sticky_vars.AddVariables(
 994     EnumVariable('TARGET_ISA', 'Target ISA', 'null', all_isa_list),
 995     EnumVariable('TARGET_GPU_ISA', 'Target GPU ISA', 'gcn3', all_gpu_isa_list),
 996     ListVariable('CPU_MODELS', 'CPU models',
 997                  sorted(n for n,m in CpuModel.dict.items() if m.default),
 998                  sorted(CpuModel.dict.keys())),
 999     BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
1000                  False),
1001     BoolVariable('USE_SSE2',
1002                  'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
1003                  False),
1004     BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
1005     BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
1006     BoolVariable('USE_PNG',  'Enable support for PNG images', have_png),
1007     BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models',
1008                  have_kvm),
1009     BoolVariable('USE_TUNTAP',
1010                  'Enable using a tap device to bridge to the host network',
1011                  have_tuntap),
1012     BoolVariable('BUILD_GPU', 'Build the compute-GPU model', False),
1013     EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1014                   all_protocols),
1015     EnumVariable('BACKTRACE_IMPL', 'Post-mortem dump implementation',
1016                  backtrace_impls[-1], backtrace_impls),
1017     ('NUMBER_BITS_PER_SET', 'Max elements in set (default 64)',
1018                  64),
1019     BoolVariable('USE_HDF5', 'Enable the HDF5 support', have_hdf5),
1020     )
1021
1022 # These variables get exported to #defines in config/*.hh (see src/SConscript).
1023 export_vars += ['USE_FENV', 'TARGET_ISA', 'TARGET_GPU_ISA',
1024                 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP', 'PROTOCOL',
1025                 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
1026                 'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG',
1027                 'NUMBER_BITS_PER_SET', 'USE_HDF5']
1028
1029 ###################################################
1030 #
1031 # Define a SCons builder for configuration flag headers.
1032 #
1033 ###################################################
1034
1035 # This function generates a config header file that #defines the
1036 # variable symbol to the current variable setting (0 or 1).  The source
1037 # operands are the name of the variable and a Value node containing the
1038 # value of the variable.
1039 def build_config_file(target, source, env):
1040     (variable, value) = [s.get_contents().decode('utf-8') for s in source]
1041     with open(str(target[0]), 'w') as f:
1042         print('#define', variable, value, file=f)
1043     return None
1044
1045 # Combine the two functions into a scons Action object.
1046 config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1047
1048 # The emitter munges the source & target node lists to reflect what
1049 # we're really doing.
1050 def config_emitter(target, source, env):
1051     # extract variable name from Builder arg
1052     variable = str(target[0])
1053     # True target is config header file
1054     target = joinpath('config', variable.lower() + '.hh')
1055     val = env[variable]
1056     if isinstance(val, bool):
1057         # Force value to 0/1
1058         val = int(val)
1059     elif isinstance(val, str):
1060         val = '"' + val + '"'
1061
1062     # Sources are variable name & value (packaged in SCons Value nodes)
1063     return ([target], [Value(variable), Value(val)])
1064
1065 config_builder = Builder(emitter = config_emitter, action = config_action)
1066
1067 main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1068
1069 ###################################################
1070 #
1071 # Builders for static and shared partially linked object files.
1072 #
1073 ###################################################
1074
1075 partial_static_builder = Builder(action=SCons.Defaults.LinkAction,
1076                                  src_suffix='$OBJSUFFIX',
1077                                  src_builder=['StaticObject', 'Object'],
1078                                  LINKFLAGS='$PLINKFLAGS',
1079                                  LIBS='')
1080
1081 def partial_shared_emitter(target, source, env):
1082     for tgt in target:
1083         tgt.attributes.shared = 1
1084     return (target, source)
1085 partial_shared_builder = Builder(action=SCons.Defaults.ShLinkAction,
1086                                  emitter=partial_shared_emitter,
1087                                  src_suffix='$SHOBJSUFFIX',
1088                                  src_builder='SharedObject',
1089                                  SHLINKFLAGS='$PSHLINKFLAGS',
1090                                  LIBS='')
1091
1092 main.Append(BUILDERS = { 'PartialShared' : partial_shared_builder,
1093                          'PartialStatic' : partial_static_builder })
1094
1095 def add_local_rpath(env, *targets):
1096     '''Set up an RPATH for a library which lives in the build directory.
1097
1098     The construction environment variable BIN_RPATH_PREFIX should be set to
1099     the relative path of the build directory starting from the location of the
1100     binary.'''
1101     for target in targets:
1102         target = env.Entry(target)
1103         if not isinstance(target, SCons.Node.FS.Dir):
1104             target = target.dir
1105         relpath = os.path.relpath(target.abspath, env['BUILDDIR'])
1106         components = [
1107             '\\$$ORIGIN',
1108             '${BIN_RPATH_PREFIX}',
1109             relpath
1110         ]
1111         env.Append(RPATH=[env.Literal(os.path.join(*components))])
1112
1113 if sys.platform != "darwin":
1114     main.Append(LINKFLAGS=Split('-z origin'))
1115
1116 main.AddMethod(add_local_rpath, 'AddLocalRPATH')
1117
1118 # builds in ext are shared across all configs in the build root.
1119 ext_dir = abspath(joinpath(str(main.root), 'ext'))
1120 ext_build_dirs = []
1121 for root, dirs, files in os.walk(ext_dir):
1122     if 'SConscript' in files:
1123         build_dir = os.path.relpath(root, ext_dir)
1124         ext_build_dirs.append(build_dir)
1125         main.SConscript(joinpath(root, 'SConscript'),
1126                         variant_dir=joinpath(build_root, build_dir))
1127
1128 gdb_xml_dir = joinpath(ext_dir, 'gdb-xml')
1129 Export('gdb_xml_dir')
1130
1131 ###################################################
1132 #
1133 # This builder and wrapper method are used to set up a directory with
1134 # switching headers. Those are headers which are in a generic location and
1135 # that include more specific headers from a directory chosen at build time
1136 # based on the current build settings.
1137 #
1138 ###################################################
1139
1140 def build_switching_header(target, source, env):
1141     path = str(target[0])
1142     subdir = str(source[0])
1143     dp, fp = os.path.split(path)
1144     dp = os.path.relpath(os.path.realpath(dp),
1145                          os.path.realpath(env['BUILDDIR']))
1146     with open(path, 'w') as hdr:
1147         print('#include "%s/%s/%s"' % (dp, subdir, fp), file=hdr)
1148
1149 switching_header_action = MakeAction(build_switching_header,
1150                                      Transform('GENERATE'))
1151
1152 switching_header_builder = Builder(action=switching_header_action,
1153                                    source_factory=Value,
1154                                    single_source=True)
1155
1156 main.Append(BUILDERS = { 'SwitchingHeader': switching_header_builder })
1157
1158 def switching_headers(self, headers, source):
1159     for header in headers:
1160         self.SwitchingHeader(header, source)
1161
1162 main.AddMethod(switching_headers, 'SwitchingHeaders')
1163
1164 ###################################################
1165 #
1166 # Define build environments for selected configurations.
1167 #
1168 ###################################################
1169
1170 for variant_path in variant_paths:
1171     if not GetOption('silent'):
1172         print("Building in", variant_path)
1173
1174     # Make a copy of the build-root environment to use for this config.
1175     env = main.Clone()
1176     env['BUILDDIR'] = variant_path
1177
1178     # variant_dir is the tail component of build path, and is used to
1179     # determine the build parameters (e.g., 'X86')
1180     (build_root, variant_dir) = splitpath(variant_path)
1181
1182     # Set env variables according to the build directory config.
1183     sticky_vars.files = []
1184     # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1185     # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1186     # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1187     current_vars_file = joinpath(build_root, 'variables', variant_dir)
1188     if isfile(current_vars_file):
1189         sticky_vars.files.append(current_vars_file)
1190         if not GetOption('silent'):
1191             print("Using saved variables file %s" % current_vars_file)
1192     elif variant_dir in ext_build_dirs:
1193         # Things in ext are built without a variant directory.
1194         continue
1195     else:
1196         # Build dir-specific variables file doesn't exist.
1197
1198         # Make sure the directory is there so we can create it later
1199         opt_dir = dirname(current_vars_file)
1200         if not isdir(opt_dir):
1201             mkdir(opt_dir)
1202
1203         # Get default build variables from source tree.  Variables are
1204         # normally determined by name of $VARIANT_DIR, but can be
1205         # overridden by '--default=' arg on command line.
1206         default = GetOption('default')
1207         opts_dir = joinpath(main.root.abspath, 'build_opts')
1208         if default:
1209             default_vars_files = [joinpath(build_root, 'variables', default),
1210                                   joinpath(opts_dir, default)]
1211         else:
1212             default_vars_files = [joinpath(opts_dir, variant_dir)]
1213         existing_files = list(filter(isfile, default_vars_files))
1214         if existing_files:
1215             default_vars_file = existing_files[0]
1216             sticky_vars.files.append(default_vars_file)
1217             print("Variables file %s not found,\n  using defaults in %s"
1218                   % (current_vars_file, default_vars_file))
1219         else:
1220             error("Cannot find variables file %s or default file(s) %s"
1221                   % (current_vars_file, ' or '.join(default_vars_files)))
1222             Exit(1)
1223
1224     # Apply current variable settings to env
1225     sticky_vars.Update(env)
1226
1227     help_texts["local_vars"] += \
1228         "Build variables for %s:\n" % variant_dir \
1229                  + sticky_vars.GenerateHelpText(env)
1230
1231     # Process variable settings.
1232
1233     if not have_fenv and env['USE_FENV']:
1234         warning("<fenv.h> not available; forcing USE_FENV to False in",
1235                 variant_dir + ".")
1236         env['USE_FENV'] = False
1237
1238     if not env['USE_FENV']:
1239         warning("No IEEE FP rounding mode control in", variant_dir + ".\n"
1240                 "FP results may deviate slightly from other platforms.")
1241
1242     if not have_png and env['USE_PNG']:
1243         warning("<png.h> not available; forcing USE_PNG to False in",
1244                 variant_dir + ".")
1245         env['USE_PNG'] = False
1246
1247     if env['USE_PNG']:
1248         env.Append(LIBS=['png'])
1249
1250     if env['EFENCE']:
1251         env.Append(LIBS=['efence'])
1252
1253     if env['USE_KVM']:
1254         if not have_kvm:
1255             warning("Can not enable KVM, host seems to lack KVM support")
1256             env['USE_KVM'] = False
1257         elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1258             print("Info: KVM support disabled due to unsupported host and "
1259                   "target ISA combination")
1260             env['USE_KVM'] = False
1261
1262     if env['USE_TUNTAP']:
1263         if not have_tuntap:
1264             warning("Can't connect EtherTap with a tap device.")
1265             env['USE_TUNTAP'] = False
1266
1267     if env['BUILD_GPU']:
1268         env.Append(CPPDEFINES=['BUILD_GPU'])
1269
1270     # Warn about missing optional functionality
1271     if env['USE_KVM']:
1272         if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1273             warning("perf_event headers lack support for the exclude_host "
1274                     "attribute. KVM instruction counts will be inaccurate.")
1275
1276     # Save sticky variable settings back to current variables file
1277     sticky_vars.Save(current_vars_file, env)
1278
1279     if env['USE_SSE2']:
1280         env.Append(CCFLAGS=['-msse2'])
1281
1282     env.Append(CCFLAGS='$CCFLAGS_EXTRA')
1283     env.Append(LINKFLAGS='$LDFLAGS_EXTRA')
1284
1285     # The src/SConscript file sets up the build rules in 'env' according
1286     # to the configured variables.  It returns a list of environments,
1287     # one for each variant build (debug, opt, etc.)
1288     SConscript('src/SConscript', variant_dir=variant_path,
1289                exports=['env', 'marshal_env'])
1290
1291 # base help text
1292 Help('''
1293 Usage: scons [scons options] [build variables] [target(s)]
1294
1295 Extra scons options:
1296 %(options)s
1297
1298 Global build variables:
1299 %(global_vars)s
1300
1301 %(local_vars)s
1302 ''' % help_texts)
1303
1304 atexit.register(summarize_warnings)