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
 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' ]),
 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     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 and \
 405        compareVersions(gcc_version, '8.1') < 0:
 406         # Incremental linking with LTO is currently broken in gcc versions
 407         # 4.9 to 8.1.
 408         #
 409         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548
 410         #
 411         # gcc versions 6.0 and greater accept an -flinker-output flag which
 412         # selects what type of output the linker should generate. This is
 413         # necessary for incremental lto to work, but is also broken in
 414         # versions of gcc up to 8.1.
 415         #
 416         # https://gcc.gnu.org/gcc-6/changes.html
 417         # https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03161.html
 418         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69866
 419         main['BROKEN_INCREMENTAL_LTO'] = True
 420
 421     disable_lto = GetOption('no_lto')
 422     if not disable_lto and main.get('BROKEN_INCREMENTAL_LTO', False) and \
 423             not GetOption('force_lto'):
 424         warning('Your compiler doesn\'t support incremental linking and lto '
 425                 'at the same time, so lto is being disabled. To force lto on '
 426                 'anyway, use the --force-lto option. That will disable '
 427                 'partial linking.')
 428         disable_lto = True
 429
 430     # Add the appropriate Link-Time Optimization (LTO) flags
 431     # unless LTO is explicitly turned off. Note that these flags
 432     # are only used by the fast target.
 433     if not disable_lto:
 434         # Pass the LTO flag when compiling to produce GIMPLE
 435         # output, we merely create the flags here and only append
 436         # them later
 437         main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 438
 439         # Use the same amount of jobs for LTO as we are running
 440         # scons with
 441         main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 442
 443     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
 444                                   '-fno-builtin-realloc', '-fno-builtin-free'])
 445
 446 elif main['CLANG']:
 447     # Check for a supported version of clang, >= 3.1 is needed to
 448     # support similar features as gcc 4.8. See
 449     # http://clang.llvm.org/cxx_status.html for details
 450     clang_version_re = re.compile(".* version (\d+\.\d+)")
 451     clang_version_match = clang_version_re.search(CXX_version)
 452     if (clang_version_match):
 453         clang_version = clang_version_match.groups()[0]
 454         if compareVersions(clang_version, "3.1") < 0:
 455             error('clang version 3.1 or newer required.\n'
 456                   'Installed version:', clang_version)
 457     else:
 458         error('Unable to determine clang version.')
 459
 460     # clang has a few additional warnings that we disable, extraneous
 461     # parantheses are allowed due to Ruby's printing of the AST,
 462     # finally self assignments are allowed as the generated CPU code
 463     # is relying on this
 464     main.Append(CCFLAGS=['-Wno-parentheses',
 465                          '-Wno-self-assign',
 466                          # Some versions of libstdc++ (4.8?) seem to
 467                          # use struct hash and class hash
 468                          # interchangeably.
 469                          '-Wno-mismatched-tags',
 470                          ])
 471
 472     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
 473
 474     # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
 475     # opposed to libstdc++, as the later is dated.
 476     if sys.platform == "darwin":
 477         main.Append(CXXFLAGS=['-stdlib=libc++'])
 478         main.Append(LIBS=['c++'])
 479
 480     # On FreeBSD we need libthr.
 481     if sys.platform.startswith('freebsd'):
 482         main.Append(LIBS=['thr'])
 483
 484 # Add sanitizers flags
 485 sanitizers=[]
 486 if GetOption('with_ubsan'):
 487     # Only gcc >= 4.9 supports UBSan, so check both the version
 488     # and the command-line option before adding the compiler and
 489     # linker flags.
 490     if not main['GCC'] or compareVersions(main['GCC_VERSION'], '4.9') >= 0:
 491         sanitizers.append('undefined')
 492 if GetOption('with_asan'):
 493     # Available for gcc >= 4.8 or llvm >= 3.1 both a requirement
 494     # by the build system
 495     sanitizers.append('address')
 496     suppressions_file = Dir('util').File('lsan-suppressions').get_abspath()
 497     suppressions_opt = 'suppressions=%s' % suppressions_file
 498     main['ENV']['LSAN_OPTIONS'] = ':'.join([suppressions_opt,
 499                                             'print_suppressions=0'])
 500     print()
 501     warning('To suppress false positive leaks, set the LSAN_OPTIONS '
 502             'environment variable to "%s" when running gem5' %
 503             suppressions_opt)
 504     warning('LSAN_OPTIONS=suppressions=%s' % suppressions_opt)
 505     print()
 506 if sanitizers:
 507     sanitizers = ','.join(sanitizers)
 508     if main['GCC'] or main['CLANG']:
 509         main.Append(CCFLAGS=['-fsanitize=%s' % sanitizers,
 510                              '-fno-omit-frame-pointer'],
 511                     LINKFLAGS='-fsanitize=%s' % sanitizers)
 512     else:
 513         warning("Don't know how to enable %s sanitizer(s) for your "
 514                 "compiler." % sanitizers)
 515
 516 # Set up common yacc/bison flags (needed for Ruby)
 517 main['YACCFLAGS'] = '-d'
 518 main['YACCHXXFILESUFFIX'] = '.hh'
 519
 520 # Do this after we save setting back, or else we'll tack on an
 521 # extra 'qdo' every time we run scons.
 522 if main['BATCH']:
 523     main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
 524     main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
 525     main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
 526     main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
 527     main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
 528
 529 if sys.platform == 'cygwin':
 530     # cygwin has some header file issues...
 531     main.Append(CCFLAGS=["-Wno-uninitialized"])
 532
 533
 534 have_pkg_config = readCommand(['pkg-config', '--version'], exception='')
 535
 536 # Check for the protobuf compiler
 537 try:
 538     main['HAVE_PROTOC'] = True
 539     protoc_version = readCommand([main['PROTOC'], '--version']).split()
 540
 541     # First two words should be "libprotoc x.y.z"
 542     if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
 543         warning('Protocol buffer compiler (protoc) not found.\n'
 544                 'Please install protobuf-compiler for tracing support.')
 545         main['HAVE_PROTOC'] = False
 546     else:
 547         # Based on the availability of the compress stream wrappers,
 548         # require 2.1.0
 549         min_protoc_version = '2.1.0'
 550         if compareVersions(protoc_version[1], min_protoc_version) < 0:
 551             warning('protoc version', min_protoc_version,
 552                     'or newer required.\n'
 553                     'Installed version:', protoc_version[1])
 554             main['HAVE_PROTOC'] = False
 555         else:
 556             # Attempt to determine the appropriate include path and
 557             # library path using pkg-config, that means we also need to
 558             # check for pkg-config. Note that it is possible to use
 559             # protobuf without the involvement of pkg-config. Later on we
 560             # check go a library config check and at that point the test
 561             # will fail if libprotobuf cannot be found.
 562             if have_pkg_config:
 563                 try:
 564                     # Attempt to establish what linking flags to add for
 565                     # protobuf
 566                     # using pkg-config
 567                     main.ParseConfig(
 568                             'pkg-config --cflags --libs-only-L protobuf')
 569                 except:
 570                     warning('pkg-config could not get protobuf flags.')
 571 except Exception as e:
 572     warning('While checking protoc version:', str(e))
 573     main['HAVE_PROTOC'] = False
 574
 575 # Check for 'timeout' from GNU coreutils. If present, regressions will
 576 # be run with a time limit. We require version 8.13 since we rely on
 577 # support for the '--foreground' option.
 578 if sys.platform.startswith('freebsd'):
 579     timeout_lines = readCommand(['gtimeout', '--version'],
 580                                 exception='').splitlines()
 581 else:
 582     timeout_lines = readCommand(['timeout', '--version'],
 583                                 exception='').splitlines()
 584 # Get the first line and tokenize it
 585 timeout_version = timeout_lines[0].split() if timeout_lines else []
 586 main['TIMEOUT'] =  timeout_version and \
 587     compareVersions(timeout_version[-1], '8.13') >= 0
 588
 589 # Add a custom Check function to test for structure members.
 590 def CheckMember(context, include, decl, member, include_quotes="<>"):
 591     context.Message("Checking for member %s in %s..." %
 592                     (member, decl))
 593     text = """
 594 #include %(header)s
 595 int main(){
 596   %(decl)s test;
 597   (void)test.%(member)s;
 598   return 0;
 599 };
 600 """ % { "header" : include_quotes[0] + include + include_quotes[1],
 601         "decl" : decl,
 602         "member" : member,
 603         }
 604
 605     ret = context.TryCompile(text, extension=".cc")
 606     context.Result(ret)
 607     return ret
 608
 609 # Platform-specific configuration.  Note again that we assume that all
 610 # builds under a given build root run on the same host platform.
 611 conf = Configure(main,
 612                  conf_dir = joinpath(build_root, '.scons_config'),
 613                  log_file = joinpath(build_root, 'scons_config.log'),
 614                  custom_tests = {
 615         'CheckMember' : CheckMember,
 616         })
 617
 618 # Check if we should compile a 64 bit binary on Mac OS X/Darwin
 619 try:
 620     import platform
 621     uname = platform.uname()
 622     if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
 623         if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
 624             main.Append(CCFLAGS=['-arch', 'x86_64'])
 625             main.Append(CFLAGS=['-arch', 'x86_64'])
 626             main.Append(LINKFLAGS=['-arch', 'x86_64'])
 627             main.Append(ASFLAGS=['-arch', 'x86_64'])
 628 except:
 629     pass
 630
 631 # Recent versions of scons substitute a "Null" object for Configure()
 632 # when configuration isn't necessary, e.g., if the "--help" option is
 633 # present.  Unfortuantely this Null object always returns false,
 634 # breaking all our configuration checks.  We replace it with our own
 635 # more optimistic null object that returns True instead.
 636 if not conf:
 637     def NullCheck(*args, **kwargs):
 638         return True
 639
 640     class NullConf:
 641         def __init__(self, env):
 642             self.env = env
 643         def Finish(self):
 644             return self.env
 645         def __getattr__(self, mname):
 646             return NullCheck
 647
 648     conf = NullConf(main)
 649
 650 # Cache build files in the supplied directory.
 651 if main['M5_BUILD_CACHE']:
 652     print('Using build cache located at', main['M5_BUILD_CACHE'])
 653     CacheDir(main['M5_BUILD_CACHE'])
 654
 655 main['USE_PYTHON'] = not GetOption('without_python')
 656 if main['USE_PYTHON']:
 657     # Find Python include and library directories for embedding the
 658     # interpreter. We rely on python-config to resolve the appropriate
 659     # includes and linker flags. ParseConfig does not seem to understand
 660     # the more exotic linker flags such as -Xlinker and -export-dynamic so
 661     # we add them explicitly below. If you want to link in an alternate
 662     # version of python, see above for instructions on how to invoke
 663     # scons with the appropriate PATH set.
 664
 665     python_config = main.Detect(main['PYTHON_CONFIG'])
 666     if python_config is None:
 667         error("Can't find a suitable python-config, tried %s" % \
 668               main['PYTHON_CONFIG'])
 669
 670     print("Info: Using Python config: %s" % (python_config, ))
 671     py_includes = readCommand([python_config, '--includes'],
 672                               exception='').split()
 673     py_includes = list(filter(
 674         lambda s: match(r'.*\/include\/.*',s), py_includes))
 675     # Strip the -I from the include folders before adding them to the
 676     # CPPPATH
 677     py_includes = list(map(
 678         lambda s: s[2:] if s.startswith('-I') else s, py_includes))
 679     main.Append(CPPPATH=py_includes)
 680
 681     # Read the linker flags and split them into libraries and other link
 682     # flags. The libraries are added later through the call the CheckLib.
 683     py_ld_flags = readCommand([python_config, '--ldflags'],
 684         exception='').split()
 685     py_libs = []
 686     for lib in py_ld_flags:
 687          if not lib.startswith('-l'):
 688              main.Append(LINKFLAGS=[lib])
 689          else:
 690              lib = lib[2:]
 691              if lib not in py_libs:
 692                  py_libs.append(lib)
 693
 694     # verify that this stuff works
 695     if not conf.CheckHeader('Python.h', '<>'):
 696         error("Check failed for Python.h header in",
 697                 ' '.join(py_includes), "\n"
 698               "Two possible reasons:\n"
 699               "1. Python headers are not installed (You can install the "
 700               "package python-dev on Ubuntu and RedHat)\n"
 701               "2. SCons is using a wrong C compiler. This can happen if "
 702               "CC has the wrong value.\n"
 703               "CC = %s" % main['CC'])
 704
 705     for lib in py_libs:
 706         if not conf.CheckLib(lib):
 707             error("Can't find library %s required by python." % lib)
 708
 709 # On Solaris you need to use libsocket for socket ops
 710 if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
 711    if not conf.CheckLibWithHeader('socket', 'sys/socket.h',
 712                                   'C++', 'accept(0,0,0);'):
 713        error("Can't find library with socket calls (e.g. accept()).")
 714
 715 # Check for zlib.  If the check passes, libz will be automatically
 716 # added to the LIBS environment variable.
 717 if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
 718     error('Did not find needed zlib compression library '
 719           'and/or zlib.h header file.\n'
 720           'Please install zlib and try again.')
 721
 722 # If we have the protobuf compiler, also make sure we have the
 723 # development libraries. If the check passes, libprotobuf will be
 724 # automatically added to the LIBS environment variable. After
 725 # this, we can use the HAVE_PROTOBUF flag to determine if we have
 726 # got both protoc and libprotobuf available.
 727 main['HAVE_PROTOBUF'] = main['HAVE_PROTOC'] and \
 728     conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
 729                             'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
 730
 731 # Valgrind gets much less confused if you tell it when you're using
 732 # alternative stacks.
 733 main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
 734
 735 # If we have the compiler but not the library, print another warning.
 736 if main['HAVE_PROTOC'] and not main['HAVE_PROTOBUF']:
 737     warning('Did not find protocol buffer library and/or headers.\n'
 738             'Please install libprotobuf-dev for tracing support.')
 739
 740 # Check for librt.
 741 have_posix_clock = \
 742     conf.CheckLibWithHeader(None, 'time.h', 'C',
 743                             'clock_nanosleep(0,0,NULL,NULL);') or \
 744     conf.CheckLibWithHeader('rt', 'time.h', 'C',
 745                             'clock_nanosleep(0,0,NULL,NULL);')
 746
 747 have_posix_timers = \
 748     conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
 749                             'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
 750
 751 if not GetOption('without_tcmalloc'):
 752     if conf.CheckLib('tcmalloc'):
 753         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 754     elif conf.CheckLib('tcmalloc_minimal'):
 755         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 756     else:
 757         warning("You can get a 12% performance improvement by "
 758                 "installing tcmalloc (libgoogle-perftools-dev package "
 759                 "on Ubuntu or RedHat).")
 760
 761
 762 # Detect back trace implementations. The last implementation in the
 763 # list will be used by default.
 764 backtrace_impls = [ "none" ]
 765
 766 backtrace_checker = 'char temp;' + \
 767     ' backtrace_symbols_fd((void*)&temp, 0, 0);'
 768 if conf.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker):
 769     backtrace_impls.append("glibc")
 770 elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
 771                              backtrace_checker):
 772     # NetBSD and FreeBSD need libexecinfo.
 773     backtrace_impls.append("glibc")
 774     main.Append(LIBS=['execinfo'])
 775
 776 if backtrace_impls[-1] == "none":
 777     default_backtrace_impl = "none"
 778     warning("No suitable back trace implementation found.")
 779
 780 if not have_posix_clock:
 781     warning("Can't find library for POSIX clocks.")
 782
 783 # Check for <fenv.h> (C99 FP environment control)
 784 have_fenv = conf.CheckHeader('fenv.h', '<>')
 785 if not have_fenv:
 786     warning("Header file <fenv.h> not found.\n"
 787             "This host has no IEEE FP rounding mode control.")
 788
 789 # Check for <png.h> (libpng library needed if wanting to dump
 790 # frame buffer image in png format)
 791 have_png = conf.CheckHeader('png.h', '<>')
 792 if not have_png:
 793     warning("Header file <png.h> not found.\n"
 794             "This host has no libpng library.\n"
 795             "Disabling support for PNG framebuffers.")
 796
 797 # Check if we should enable KVM-based hardware virtualization. The API
 798 # we rely on exists since version 2.6.36 of the kernel, but somehow
 799 # the KVM_API_VERSION does not reflect the change. We test for one of
 800 # the types as a fall back.
 801 have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
 802 if not have_kvm:
 803     print("Info: Compatible header file <linux/kvm.h> not found, "
 804           "disabling KVM support.")
 805
 806 # Check if the TUN/TAP driver is available.
 807 have_tuntap = conf.CheckHeader('linux/if_tun.h', '<>')
 808 if not have_tuntap:
 809     print("Info: Compatible header file <linux/if_tun.h> not found.")
 810
 811 # x86 needs support for xsave. We test for the structure here since we
 812 # won't be able to run new tests by the time we know which ISA we're
 813 # targeting.
 814 have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
 815                                     '#include <linux/kvm.h>') != 0
 816
 817 # Check if the requested target ISA is compatible with the host
 818 def is_isa_kvm_compatible(isa):
 819     try:
 820         import platform
 821         host_isa = platform.machine()
 822     except:
 823         warning("Failed to determine host ISA.")
 824         return False
 825
 826     if not have_posix_timers:
 827         warning("Can not enable KVM, host seems to lack support "
 828                 "for POSIX timers")
 829         return False
 830
 831     if isa == "arm":
 832         return host_isa in ( "armv7l", "aarch64" )
 833     elif isa == "x86":
 834         if host_isa != "x86_64":
 835             return False
 836
 837         if not have_kvm_xsave:
 838             warning("KVM on x86 requires xsave support in kernel headers.")
 839             return False
 840
 841         return True
 842     else:
 843         return False
 844
 845
 846 # Check if the exclude_host attribute is available. We want this to
 847 # get accurate instruction counts in KVM.
 848 main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
 849     'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
 850
 851 def check_hdf5():
 852     return \
 853         conf.CheckLibWithHeader('hdf5', 'hdf5.h', 'C',
 854                                 'H5Fcreate("", 0, 0, 0);') and \
 855         conf.CheckLibWithHeader('hdf5_cpp', 'H5Cpp.h', 'C++',
 856                                 'H5::H5File("", 0);')
 857
 858 def check_hdf5_pkg(name):
 859     print("Checking for %s using pkg-config..." % name, end="")
 860     if not have_pkg_config:
 861         print(" pkg-config not found")
 862         return False
 863
 864     try:
 865         main.ParseConfig('pkg-config --cflags-only-I --libs-only-L %s' % name)
 866         print(" yes")
 867         return True
 868     except:
 869         print(" no")
 870         return False
 871
 872 # Check if there is a pkg-config configuration for hdf5. If we find
 873 # it, setup the environment to enable linking and header inclusion. We
 874 # don't actually try to include any headers or link with hdf5 at this
 875 # stage.
 876 if not check_hdf5_pkg('hdf5-serial'):
 877     check_hdf5_pkg('hdf5')
 878
 879 # Check if the HDF5 libraries can be found. This check respects the
 880 # include path and library path provided by pkg-config. We perform
 881 # this check even if there isn't a pkg-config configuration for hdf5
 882 # since some installations don't use pkg-config.
 883 have_hdf5 = check_hdf5()
 884 if not have_hdf5:
 885     print("Warning: Couldn't find any HDF5 C++ libraries. Disabling")
 886     print("         HDF5 support.")
 887
 888 ######################################################################
 889 #
 890 # Finish the configuration
 891 #
 892 main = conf.Finish()
 893
 894 ######################################################################
 895 #
 896 # Collect all non-global variables
 897 #
 898
 899 # Define the universe of supported ISAs
 900 all_isa_list = [ ]
 901 all_gpu_isa_list = [ ]
 902 Export('all_isa_list')
 903 Export('all_gpu_isa_list')
 904
 905 class CpuModel(object):
 906     '''The CpuModel class encapsulates everything the ISA parser needs to
 907     know about a particular CPU model.'''
 908
 909     # Dict of available CPU model objects.  Accessible as CpuModel.dict.
 910     dict = {}
 911
 912     # Constructor.  Automatically adds models to CpuModel.dict.
 913     def __init__(self, name, default=False):
 914         self.name = name           # name of model
 915
 916         # This cpu is enabled by default
 917         self.default = default
 918
 919         # Add self to dict
 920         if name in CpuModel.dict:
 921             raise AttributeError("CpuModel '%s' already registered" % name)
 922         CpuModel.dict[name] = self
 923
 924 Export('CpuModel')
 925
 926 # Sticky variables get saved in the variables file so they persist from
 927 # one invocation to the next (unless overridden, in which case the new
 928 # value becomes sticky).
 929 sticky_vars = Variables(args=ARGUMENTS)
 930 Export('sticky_vars')
 931
 932 # Sticky variables that should be exported
 933 export_vars = []
 934 Export('export_vars')
 935
 936 # For Ruby
 937 all_protocols = []
 938 Export('all_protocols')
 939 protocol_dirs = []
 940 Export('protocol_dirs')
 941 slicc_includes = []
 942 Export('slicc_includes')
 943
 944 # Walk the tree and execute all SConsopts scripts that wil add to the
 945 # above variables
 946 if GetOption('verbose'):
 947     print("Reading SConsopts")
 948 for bdir in [ base_dir ] + extras_dir_list:
 949     if not isdir(bdir):
 950         error("Directory '%s' does not exist." % bdir)
 951     for root, dirs, files in os.walk(bdir):
 952         if 'SConsopts' in files:
 953             if GetOption('verbose'):
 954                 print("Reading", joinpath(root, 'SConsopts'))
 955             SConscript(joinpath(root, 'SConsopts'))
 956
 957 all_isa_list.sort()
 958 all_gpu_isa_list.sort()
 959
 960 sticky_vars.AddVariables(
 961     EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
 962     EnumVariable('TARGET_GPU_ISA', 'Target GPU ISA', 'hsail', all_gpu_isa_list),
 963     ListVariable('CPU_MODELS', 'CPU models',
 964                  sorted(n for n,m in CpuModel.dict.items() if m.default),
 965                  sorted(CpuModel.dict.keys())),
 966     BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
 967                  False),
 968     BoolVariable('USE_SSE2',
 969                  'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
 970                  False),
 971     BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
 972     BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
 973     BoolVariable('USE_PNG',  'Enable support for PNG images', have_png),
 974     BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability',
 975                  False),
 976     BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models',
 977                  have_kvm),
 978     BoolVariable('USE_TUNTAP',
 979                  'Enable using a tap device to bridge to the host network',
 980                  have_tuntap),
 981     BoolVariable('BUILD_GPU', 'Build the compute-GPU model', False),
 982     EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
 983                   all_protocols),
 984     EnumVariable('BACKTRACE_IMPL', 'Post-mortem dump implementation',
 985                  backtrace_impls[-1], backtrace_impls),
 986     ('NUMBER_BITS_PER_SET', 'Max elements in set (default 64)',
 987                  64),
 988     BoolVariable('USE_HDF5', 'Enable the HDF5 support', have_hdf5),
 989     )
 990
 991 # These variables get exported to #defines in config/*.hh (see src/SConscript).
 992 export_vars += ['USE_FENV', 'TARGET_ISA', 'TARGET_GPU_ISA', 'CP_ANNOTATE',
 993                 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP', 'PROTOCOL',
 994                 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
 995                 'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG',
 996                 'NUMBER_BITS_PER_SET', 'USE_HDF5']
 997
 998 ###################################################
 999 #
1000 # Define a SCons builder for configuration flag headers.
1001 #
1002 ###################################################
1003
1004 # This function generates a config header file that #defines the
1005 # variable symbol to the current variable setting (0 or 1).  The source
1006 # operands are the name of the variable and a Value node containing the
1007 # value of the variable.
1008 def build_config_file(target, source, env):
1009     (variable, value) = [s.get_contents().decode('utf-8') for s in source]
1010     with open(str(target[0]), 'w') as f:
1011         print('#define', variable, value, file=f)
1012     return None
1013
1014 # Combine the two functions into a scons Action object.
1015 config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1016
1017 # The emitter munges the source & target node lists to reflect what
1018 # we're really doing.
1019 def config_emitter(target, source, env):
1020     # extract variable name from Builder arg
1021     variable = str(target[0])
1022     # True target is config header file
1023     target = joinpath('config', variable.lower() + '.hh')
1024     val = env[variable]
1025     if isinstance(val, bool):
1026         # Force value to 0/1
1027         val = int(val)
1028     elif isinstance(val, str):
1029         val = '"' + val + '"'
1030
1031     # Sources are variable name & value (packaged in SCons Value nodes)
1032     return ([target], [Value(variable), Value(val)])
1033
1034 config_builder = Builder(emitter = config_emitter, action = config_action)
1035
1036 main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1037
1038 ###################################################
1039 #
1040 # Builders for static and shared partially linked object files.
1041 #
1042 ###################################################
1043
1044 partial_static_builder = Builder(action=SCons.Defaults.LinkAction,
1045                                  src_suffix='$OBJSUFFIX',
1046                                  src_builder=['StaticObject', 'Object'],
1047                                  LINKFLAGS='$PLINKFLAGS',
1048                                  LIBS='')
1049
1050 def partial_shared_emitter(target, source, env):
1051     for tgt in target:
1052         tgt.attributes.shared = 1
1053     return (target, source)
1054 partial_shared_builder = Builder(action=SCons.Defaults.ShLinkAction,
1055                                  emitter=partial_shared_emitter,
1056                                  src_suffix='$SHOBJSUFFIX',
1057                                  src_builder='SharedObject',
1058                                  SHLINKFLAGS='$PSHLINKFLAGS',
1059                                  LIBS='')
1060
1061 main.Append(BUILDERS = { 'PartialShared' : partial_shared_builder,
1062                          'PartialStatic' : partial_static_builder })
1063
1064 def add_local_rpath(env, *targets):
1065     '''Set up an RPATH for a library which lives in the build directory.
1066
1067     The construction environment variable BIN_RPATH_PREFIX should be set to
1068     the relative path of the build directory starting from the location of the
1069     binary.'''
1070     for target in targets:
1071         target = env.Entry(target)
1072         if not isinstance(target, SCons.Node.FS.Dir):
1073             target = target.dir
1074         relpath = os.path.relpath(target.abspath, env['BUILDDIR'])
1075         components = [
1076             '\\$$ORIGIN',
1077             '${BIN_RPATH_PREFIX}',
1078             relpath
1079         ]
1080         env.Append(RPATH=[env.Literal(os.path.join(*components))])
1081
1082 if sys.platform != "darwin":
1083     main.Append(LINKFLAGS=Split('-z origin'))
1084
1085 main.AddMethod(add_local_rpath, 'AddLocalRPATH')
1086
1087 # builds in ext are shared across all configs in the build root.
1088 ext_dir = abspath(joinpath(str(main.root), 'ext'))
1089 ext_build_dirs = []
1090 for root, dirs, files in os.walk(ext_dir):
1091     if 'SConscript' in files:
1092         build_dir = os.path.relpath(root, ext_dir)
1093         ext_build_dirs.append(build_dir)
1094         main.SConscript(joinpath(root, 'SConscript'),
1095                         variant_dir=joinpath(build_root, build_dir))
1096
1097 gdb_xml_dir = joinpath(ext_dir, 'gdb-xml')
1098 Export('gdb_xml_dir')
1099
1100 main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
1101
1102 ###################################################
1103 #
1104 # This builder and wrapper method are used to set up a directory with
1105 # switching headers. Those are headers which are in a generic location and
1106 # that include more specific headers from a directory chosen at build time
1107 # based on the current build settings.
1108 #
1109 ###################################################
1110
1111 def build_switching_header(target, source, env):
1112     path = str(target[0])
1113     subdir = str(source[0])
1114     dp, fp = os.path.split(path)
1115     dp = os.path.relpath(os.path.realpath(dp),
1116                          os.path.realpath(env['BUILDDIR']))
1117     with open(path, 'w') as hdr:
1118         print('#include "%s/%s/%s"' % (dp, subdir, fp), file=hdr)
1119
1120 switching_header_action = MakeAction(build_switching_header,
1121                                      Transform('GENERATE'))
1122
1123 switching_header_builder = Builder(action=switching_header_action,
1124                                    source_factory=Value,
1125                                    single_source=True)
1126
1127 main.Append(BUILDERS = { 'SwitchingHeader': switching_header_builder })
1128
1129 def switching_headers(self, headers, source):
1130     for header in headers:
1131         self.SwitchingHeader(header, source)
1132
1133 main.AddMethod(switching_headers, 'SwitchingHeaders')
1134
1135 ###################################################
1136 #
1137 # Define build environments for selected configurations.
1138 #
1139 ###################################################
1140
1141 for variant_path in variant_paths:
1142     if not GetOption('silent'):
1143         print("Building in", variant_path)
1144
1145     # Make a copy of the build-root environment to use for this config.
1146     env = main.Clone()
1147     env['BUILDDIR'] = variant_path
1148
1149     # variant_dir is the tail component of build path, and is used to
1150     # determine the build parameters (e.g., 'X86')
1151     (build_root, variant_dir) = splitpath(variant_path)
1152
1153     # Set env variables according to the build directory config.
1154     sticky_vars.files = []
1155     # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1156     # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1157     # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1158     current_vars_file = joinpath(build_root, 'variables', variant_dir)
1159     if isfile(current_vars_file):
1160         sticky_vars.files.append(current_vars_file)
1161         if not GetOption('silent'):
1162             print("Using saved variables file %s" % current_vars_file)
1163     elif variant_dir in ext_build_dirs:
1164         # Things in ext are built without a variant directory.
1165         continue
1166     else:
1167         # Build dir-specific variables file doesn't exist.
1168
1169         # Make sure the directory is there so we can create it later
1170         opt_dir = dirname(current_vars_file)
1171         if not isdir(opt_dir):
1172             mkdir(opt_dir)
1173
1174         # Get default build variables from source tree.  Variables are
1175         # normally determined by name of $VARIANT_DIR, but can be
1176         # overridden by '--default=' arg on command line.
1177         default = GetOption('default')
1178         opts_dir = joinpath(main.root.abspath, 'build_opts')
1179         if default:
1180             default_vars_files = [joinpath(build_root, 'variables', default),
1181                                   joinpath(opts_dir, default)]
1182         else:
1183             default_vars_files = [joinpath(opts_dir, variant_dir)]
1184         existing_files = list(filter(isfile, default_vars_files))
1185         if existing_files:
1186             default_vars_file = existing_files[0]
1187             sticky_vars.files.append(default_vars_file)
1188             print("Variables file %s not found,\n  using defaults in %s"
1189                   % (current_vars_file, default_vars_file))
1190         else:
1191             error("Cannot find variables file %s or default file(s) %s"
1192                   % (current_vars_file, ' or '.join(default_vars_files)))
1193             Exit(1)
1194
1195     # Apply current variable settings to env
1196     sticky_vars.Update(env)
1197
1198     help_texts["local_vars"] += \
1199         "Build variables for %s:\n" % variant_dir \
1200                  + sticky_vars.GenerateHelpText(env)
1201
1202     # Process variable settings.
1203
1204     if not have_fenv and env['USE_FENV']:
1205         warning("<fenv.h> not available; forcing USE_FENV to False in",
1206                 variant_dir + ".")
1207         env['USE_FENV'] = False
1208
1209     if not env['USE_FENV']:
1210         warning("No IEEE FP rounding mode control in", variant_dir + ".\n"
1211                 "FP results may deviate slightly from other platforms.")
1212
1213     if not have_png and env['USE_PNG']:
1214         warning("<png.h> not available; forcing USE_PNG to False in",
1215                 variant_dir + ".")
1216         env['USE_PNG'] = False
1217
1218     if env['USE_PNG']:
1219         env.Append(LIBS=['png'])
1220
1221     if env['EFENCE']:
1222         env.Append(LIBS=['efence'])
1223
1224     if env['USE_KVM']:
1225         if not have_kvm:
1226             warning("Can not enable KVM, host seems to lack KVM support")
1227             env['USE_KVM'] = False
1228         elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1229             print("Info: KVM support disabled due to unsupported host and "
1230                   "target ISA combination")
1231             env['USE_KVM'] = False
1232
1233     if env['USE_TUNTAP']:
1234         if not have_tuntap:
1235             warning("Can't connect EtherTap with a tap device.")
1236             env['USE_TUNTAP'] = False
1237
1238     if env['BUILD_GPU']:
1239         env.Append(CPPDEFINES=['BUILD_GPU'])
1240
1241     # Warn about missing optional functionality
1242     if env['USE_KVM']:
1243         if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1244             warning("perf_event headers lack support for the exclude_host "
1245                     "attribute. KVM instruction counts will be inaccurate.")
1246
1247     # Save sticky variable settings back to current variables file
1248     sticky_vars.Save(current_vars_file, env)
1249
1250     if env['USE_SSE2']:
1251         env.Append(CCFLAGS=['-msse2'])
1252
1253     env.Append(CCFLAGS='$CCFLAGS_EXTRA')
1254     env.Append(LINKFLAGS='$LDFLAGS_EXTRA')
1255
1256     # The src/SConscript file sets up the build rules in 'env' according
1257     # to the configured variables.  It returns a list of environments,
1258     # one for each variant build (debug, opt, etc.)
1259     SConscript('src/SConscript', variant_dir = variant_path, exports = 'env')
1260
1261 # base help text
1262 Help('''
1263 Usage: scons [scons options] [build variables] [target(s)]
1264
1265 Extra scons options:
1266 %(options)s
1267
1268 Global build variables:
1269 %(global_vars)s
1270
1271 %(local_vars)s
1272 ''' % help_texts)
1273
1274 atexit.register(summarize_warnings)