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