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 # Global Python includes
  79 import atexit
  80 import itertools
  81 import os
  82 import re
  83 import shutil
  84 import subprocess
  85 import sys
  86
  87 from os import mkdir, environ
  88 from os.path import abspath, basename, dirname, expanduser, normpath
  89 from os.path import exists,  isdir, isfile
  90 from os.path import join as joinpath, split as splitpath
  91 from re import match
  92
  93 # SCons includes
  94 import SCons
  95 import SCons.Node
  96 import SCons.Node.FS
  97
  98 from m5.util import compareVersions, readCommand, readCommandWithReturn
  99
 100 AddOption('--colors', dest='use_colors', action='store_true',
 101           help="Add color to abbreviated scons output")
 102 AddOption('--no-colors', dest='use_colors', action='store_false',
 103           help="Don't add color to abbreviated scons output")
 104 AddOption('--with-cxx-config', action='store_true',
 105           help="Build with support for C++-based configuration")
 106 AddOption('--default',
 107           help='Override which build_opts file to use for defaults')
 108 AddOption('--ignore-style', action='store_true',
 109           help='Disable style checking hooks')
 110 AddOption('--gold-linker', action='store_true', help='Use the gold linker')
 111 AddOption('--no-compress-debug', action='store_true',
 112           help="Don't compress debug info in build files")
 113 AddOption('--no-lto', action='store_true',
 114           help='Disable Link-Time Optimization for fast')
 115 AddOption('--force-lto', action='store_true',
 116           help='Use Link-Time Optimization instead of partial linking' +
 117                ' when the compiler doesn\'t support using them together.')
 118 AddOption('--verbose', action='store_true',
 119           help='Print full tool command lines')
 120 AddOption('--without-python', action='store_true',
 121           help='Build without Python configuration support')
 122 AddOption('--without-tcmalloc', action='store_true',
 123           help='Disable linking against tcmalloc')
 124 AddOption('--with-ubsan', action='store_true',
 125           help='Build with Undefined Behavior Sanitizer if available')
 126 AddOption('--with-asan', action='store_true',
 127           help='Build with Address Sanitizer if available')
 128 AddOption('--with-systemc-tests', action='store_true',
 129           help='Build systemc tests')
 130
 131 from gem5_scons import Transform, error, warning, summarize_warnings
 132
 133 if GetOption('no_lto') and GetOption('force_lto'):
 134     error('--no-lto and --force-lto are mutually exclusive')
 135
 136 ########################################################################
 137 #
 138 # Set up the main build environment.
 139 #
 140 ########################################################################
 141
 142 main = Environment(tools=['default', 'git'])
 143
 144 from gem5_scons.util import get_termcap
 145 termcap = get_termcap()
 146
 147 main_dict_keys = main.Dictionary().keys()
 148
 149 # Check that we have a C/C++ compiler
 150 if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
 151     error("No C++ compiler installed (package g++ on Ubuntu and RedHat)")
 152
 153 ###################################################
 154 #
 155 # Figure out which configurations to set up based on the path(s) of
 156 # the target(s).
 157 #
 158 ###################################################
 159
 160 # Find default configuration & binary.
 161 Default(environ.get('M5_DEFAULT_BINARY', 'build/ARM/gem5.debug'))
 162
 163 # helper function: find last occurrence of element in list
 164 def rfind(l, elt, offs = -1):
 165     for i in range(len(l)+offs, 0, -1):
 166         if l[i] == elt:
 167             return i
 168     raise ValueError("element not found")
 169
 170 # Take a list of paths (or SCons Nodes) and return a list with all
 171 # paths made absolute and ~-expanded.  Paths will be interpreted
 172 # relative to the launch directory unless a different root is provided
 173 def makePathListAbsolute(path_list, root=GetLaunchDir()):
 174     return [abspath(joinpath(root, expanduser(str(p))))
 175             for p in path_list]
 176
 177 # Each target must have 'build' in the interior of the path; the
 178 # directory below this will determine the build parameters.  For
 179 # example, for target 'foo/bar/build/X86/arch/x86/blah.do' we
 180 # recognize that X86 specifies the configuration because it
 181 # follow 'build' in the build path.
 182
 183 # The funky assignment to "[:]" is needed to replace the list contents
 184 # in place rather than reassign the symbol to a new list, which
 185 # doesn't work (obviously!).
 186 BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
 187
 188 # Generate a list of the unique build roots and configs that the
 189 # collected targets reference.
 190 variant_paths = []
 191 build_root = None
 192 for t in BUILD_TARGETS:
 193     path_dirs = t.split('/')
 194     try:
 195         build_top = rfind(path_dirs, 'build', -2)
 196     except:
 197         error("No non-leaf 'build' dir found on target path.", t)
 198     this_build_root = joinpath('/',*path_dirs[:build_top+1])
 199     if not build_root:
 200         build_root = this_build_root
 201     else:
 202         if this_build_root != build_root:
 203             error("build targets not under same build root\n"
 204                   "  %s\n  %s" % (build_root, this_build_root))
 205     variant_path = joinpath('/',*path_dirs[:build_top+2])
 206     if variant_path not in variant_paths:
 207         variant_paths.append(variant_path)
 208
 209 # Make sure build_root exists (might not if this is the first build there)
 210 if not isdir(build_root):
 211     mkdir(build_root)
 212 main['BUILDROOT'] = build_root
 213
 214 Export('main')
 215
 216 main.SConsignFile(joinpath(build_root, "sconsign"))
 217
 218 # Default duplicate option is to use hard links, but this messes up
 219 # when you use emacs to edit a file in the target dir, as emacs moves
 220 # file to file~ then copies to file, breaking the link.  Symbolic
 221 # (soft) links work better.
 222 main.SetOption('duplicate', 'soft-copy')
 223
 224 #
 225 # Set up global sticky variables... these are common to an entire build
 226 # tree (not specific to a particular build like X86)
 227 #
 228
 229 global_vars_file = joinpath(build_root, 'variables.global')
 230
 231 global_vars = Variables(global_vars_file, args=ARGUMENTS)
 232
 233 global_vars.AddVariables(
 234     ('CC', 'C compiler', environ.get('CC', main['CC'])),
 235     ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
 236     ('CCFLAGS_EXTRA', 'Extra C and C++ compiler flags', ''),
 237     ('LDFLAGS_EXTRA', 'Extra linker flags', ''),
 238     ('MARSHAL_CCFLAGS_EXTRA', 'Extra C and C++ marshal compiler flags', ''),
 239     ('MARSHAL_LDFLAGS_EXTRA', 'Extra marshal linker flags', ''),
 240     ('PYTHON_CONFIG', 'Python config binary to use',
 241      [ 'python3-config', 'python-config']
 242     ),
 243     ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
 244     ('BATCH', 'Use batch pool for build and tests', False),
 245     ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
 246     ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
 247     ('EXTRAS', 'Add extra directories to the compilation', '')
 248     )
 249
 250 # Update main environment with values from ARGUMENTS & global_vars_file
 251 global_vars.Update(main)
 252 Help('''
 253 Global build variables:
 254 {help}
 255 '''.format(help=global_vars.GenerateHelpText(main)), append=True)
 256
 257 # Save sticky variable settings back to current variables file
 258 global_vars.Save(global_vars_file, main)
 259
 260 # Parse EXTRAS variable to build list of all directories where we're
 261 # look for sources etc.  This list is exported as extras_dir_list.
 262 base_dir = Dir('#src').abspath
 263 if main['EXTRAS']:
 264     extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
 265 else:
 266     extras_dir_list = []
 267
 268 Export('base_dir')
 269 Export('extras_dir_list')
 270
 271 # the ext directory should be on the #includes path
 272 main.Append(CPPPATH=[Dir('ext')])
 273
 274 # Add shared top-level headers
 275 main.Prepend(CPPPATH=Dir('include'))
 276
 277 if GetOption('verbose'):
 278     def MakeAction(action, string, *args, **kwargs):
 279         return Action(action, *args, **kwargs)
 280 else:
 281     MakeAction = Action
 282     main['CCCOMSTR']        = Transform("CC")
 283     main['CXXCOMSTR']       = Transform("CXX")
 284     main['ASCOMSTR']        = Transform("AS")
 285     main['ARCOMSTR']        = Transform("AR", 0)
 286     main['LINKCOMSTR']      = Transform("LINK", 0)
 287     main['SHLINKCOMSTR']    = Transform("SHLINK", 0)
 288     main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
 289     main['M4COMSTR']        = Transform("M4")
 290     main['SHCCCOMSTR']      = Transform("SHCC")
 291     main['SHCXXCOMSTR']     = Transform("SHCXX")
 292 Export('MakeAction')
 293
 294 # Initialize the Link-Time Optimization (LTO) flags
 295 main['LTO_CCFLAGS'] = []
 296 main['LTO_LDFLAGS'] = []
 297
 298 # According to the readme, tcmalloc works best if the compiler doesn't
 299 # assume that we're using the builtin malloc and friends. These flags
 300 # are compiler-specific, so we need to set them after we detect which
 301 # compiler we're using.
 302 main['TCMALLOC_CCFLAGS'] = []
 303
 304 CXX_version = readCommand([main['CXX'],'--version'], exception=False)
 305 CXX_V = readCommand([main['CXX'],'-V'], exception=False)
 306
 307 main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
 308 main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
 309 if main['GCC'] + main['CLANG'] > 1:
 310     error('Two compilers enabled at once?')
 311
 312 # Set up default C++ compiler flags
 313 if main['GCC'] or main['CLANG']:
 314     # As gcc and clang share many flags, do the common parts here
 315     main.Append(CCFLAGS=['-pipe'])
 316     main.Append(CCFLAGS=['-fno-strict-aliasing'])
 317     # Enable -Wall and -Wextra and then disable the few warnings that
 318     # we consistently violate
 319     main.Append(CCFLAGS=['-Wall', '-Wundef', '-Wextra',
 320                          '-Wno-sign-compare', '-Wno-unused-parameter'])
 321     # We always compile using C++14
 322     main.Append(CXXFLAGS=['-std=c++14'])
 323     if sys.platform.startswith('freebsd'):
 324         main.Append(CCFLAGS=['-I/usr/local/include'])
 325         main.Append(CXXFLAGS=['-I/usr/local/include'])
 326
 327     # On Mac OS X/Darwin the default linker doesn't support the
 328     # option --as-needed
 329     if sys.platform != "darwin":
 330         main.Append(LINKFLAGS='-Wl,--as-needed')
 331     main['FILTER_PSHLINKFLAGS'] = lambda x: str(x).replace(' -shared', '')
 332     main['PSHLINKFLAGS'] = main.subst('${FILTER_PSHLINKFLAGS(SHLINKFLAGS)}')
 333     if GetOption('gold_linker'):
 334         main.Append(LINKFLAGS='-fuse-ld=gold')
 335     main['PLINKFLAGS'] = main.get('LINKFLAGS')
 336     shared_partial_flags = ['-r', '-nostdlib']
 337     main.Append(PSHLINKFLAGS=shared_partial_flags)
 338     main.Append(PLINKFLAGS=shared_partial_flags)
 339
 340     # Treat warnings as errors but white list some warnings that we
 341     # want to allow (e.g., deprecation warnings).
 342     main.Append(CCFLAGS=['-Werror',
 343                          '-Wno-error=deprecated-declarations',
 344                          '-Wno-error=deprecated',
 345                         ])
 346 else:
 347     error('\n'.join((
 348           "Don't know what compiler options to use for your compiler.",
 349           "compiler: " + main['CXX'],
 350           "version: " + CXX_version.replace('\n', '<nl>') if
 351                 CXX_version else 'COMMAND NOT FOUND!',
 352           "If you're trying to use a compiler other than GCC",
 353           "or clang, there appears to be something wrong with your",
 354           "environment.",
 355           "",
 356           "If you are trying to use a compiler other than those listed",
 357           "above you will need to ease fix SConstruct and ",
 358           "src/SConscript to support that compiler.")))
 359
 360 if main['GCC']:
 361     gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
 362     if compareVersions(gcc_version, "5") < 0:
 363         error('gcc version 5 or newer required.\n'
 364               'Installed version:', gcc_version)
 365         Exit(1)
 366
 367     main['GCC_VERSION'] = gcc_version
 368
 369     # Incremental linking with LTO is currently broken in gcc versions
 370     # 4.9 and above. A version where everything works completely hasn't
 371     # yet been identified.
 372     #
 373     # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548
 374     main['BROKEN_INCREMENTAL_LTO'] = True
 375
 376     if compareVersions(gcc_version, '6.0') >= 0:
 377         # gcc versions 6.0 and greater accept an -flinker-output flag which
 378         # selects what type of output the linker should generate. This is
 379         # necessary for incremental lto to work, but is also broken in
 380         # current versions of gcc. It may not be necessary in future
 381         # versions. We add it here since it might be, and as a reminder that
 382         # it exists. It's excluded if lto is being forced.
 383         #
 384         # https://gcc.gnu.org/gcc-6/changes.html
 385         # https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03161.html
 386         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69866
 387         if not GetOption('force_lto'):
 388             main.Append(PSHLINKFLAGS=['-flinker-output=rel'])
 389             main.Append(PLINKFLAGS=['-flinker-output=rel'])
 390
 391     disable_lto = GetOption('no_lto')
 392     if not disable_lto and main.get('BROKEN_INCREMENTAL_LTO', False) and \
 393             not GetOption('force_lto'):
 394         warning('Your compiler doesn\'t support incremental linking and lto '
 395                 'at the same time, so lto is being disabled. To force lto on '
 396                 'anyway, use the --force-lto option. That will disable '
 397                 'partial linking.')
 398         disable_lto = True
 399
 400     # Add the appropriate Link-Time Optimization (LTO) flags
 401     # unless LTO is explicitly turned off. Note that these flags
 402     # are only used by the fast target.
 403     if not disable_lto:
 404         # Pass the LTO flag when compiling to produce GIMPLE
 405         # output, we merely create the flags here and only append
 406         # them later
 407         main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 408
 409         # Use the same amount of jobs for LTO as we are running
 410         # scons with
 411         main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 412
 413     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
 414                                   '-fno-builtin-realloc', '-fno-builtin-free'])
 415
 416 elif main['CLANG']:
 417     clang_version_re = re.compile(".* version (\d+\.\d+)")
 418     clang_version_match = clang_version_re.search(CXX_version)
 419     if (clang_version_match):
 420         clang_version = clang_version_match.groups()[0]
 421         if compareVersions(clang_version, "3.9") < 0:
 422             error('clang version 3.9 or newer required.\n'
 423                   'Installed version:', clang_version)
 424     else:
 425         error('Unable to determine clang version.')
 426
 427     # clang has a few additional warnings that we disable, extraneous
 428     # parantheses are allowed due to Ruby's printing of the AST,
 429     # finally self assignments are allowed as the generated CPU code
 430     # is relying on this
 431     main.Append(CCFLAGS=['-Wno-parentheses',
 432                          '-Wno-self-assign',
 433                          # Some versions of libstdc++ (4.8?) seem to
 434                          # use struct hash and class hash
 435                          # interchangeably.
 436                          '-Wno-mismatched-tags',
 437                          ])
 438     if sys.platform != "darwin" and \
 439        compareVersions(clang_version, "10.0") >= 0:
 440         main.Append(CCFLAGS=['-Wno-c99-designator'])
 441
 442     if compareVersions(clang_version, "8.0") >= 0:
 443         main.Append(CCFLAGS=['-Wno-defaulted-function-deleted'])
 444
 445     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
 446
 447     # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
 448     # opposed to libstdc++, as the later is dated.
 449     if sys.platform == "darwin":
 450         main.Append(CXXFLAGS=['-stdlib=libc++'])
 451         main.Append(LIBS=['c++'])
 452
 453     # On FreeBSD we need libthr.
 454     if sys.platform.startswith('freebsd'):
 455         main.Append(LIBS=['thr'])
 456
 457 # Add sanitizers flags
 458 sanitizers=[]
 459 if GetOption('with_ubsan'):
 460     sanitizers.append('undefined')
 461 if GetOption('with_asan'):
 462     # Available for gcc >= 5 or llvm >= 3.1 both a requirement
 463     # by the build system
 464     sanitizers.append('address')
 465     suppressions_file = Dir('util').File('lsan-suppressions').get_abspath()
 466     suppressions_opt = 'suppressions=%s' % suppressions_file
 467     main['ENV']['LSAN_OPTIONS'] = ':'.join([suppressions_opt,
 468                                             'print_suppressions=0'])
 469     print()
 470     warning('To suppress false positive leaks, set the LSAN_OPTIONS '
 471             'environment variable to "%s" when running gem5' %
 472             suppressions_opt)
 473     warning('LSAN_OPTIONS=suppressions=%s' % suppressions_opt)
 474     print()
 475 if sanitizers:
 476     sanitizers = ','.join(sanitizers)
 477     if main['GCC'] or main['CLANG']:
 478         main.Append(CCFLAGS=['-fsanitize=%s' % sanitizers,
 479                              '-fno-omit-frame-pointer'],
 480                     LINKFLAGS='-fsanitize=%s' % sanitizers)
 481     else:
 482         warning("Don't know how to enable %s sanitizer(s) for your "
 483                 "compiler." % sanitizers)
 484
 485 # Set up common yacc/bison flags (needed for Ruby)
 486 main['YACCFLAGS'] = '-d'
 487 main['YACCHXXFILESUFFIX'] = '.hh'
 488
 489 # Do this after we save setting back, or else we'll tack on an
 490 # extra 'qdo' every time we run scons.
 491 if main['BATCH']:
 492     main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
 493     main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
 494     main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
 495     main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
 496     main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
 497
 498 if sys.platform == 'cygwin':
 499     # cygwin has some header file issues...
 500     main.Append(CCFLAGS=["-Wno-uninitialized"])
 501
 502
 503 have_pkg_config = readCommand(['pkg-config', '--version'], exception='')
 504
 505 # Check for the protobuf compiler
 506 try:
 507     main['HAVE_PROTOC'] = True
 508     protoc_version = readCommand([main['PROTOC'], '--version']).split()
 509
 510     # First two words should be "libprotoc x.y.z"
 511     if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
 512         warning('Protocol buffer compiler (protoc) not found.\n'
 513                 'Please install protobuf-compiler for tracing support.')
 514         main['HAVE_PROTOC'] = False
 515     else:
 516         # Based on the availability of the compress stream wrappers,
 517         # require 2.1.0
 518         min_protoc_version = '2.1.0'
 519         if compareVersions(protoc_version[1], min_protoc_version) < 0:
 520             warning('protoc version', min_protoc_version,
 521                     'or newer required.\n'
 522                     'Installed version:', protoc_version[1])
 523             main['HAVE_PROTOC'] = False
 524         else:
 525             # Attempt to determine the appropriate include path and
 526             # library path using pkg-config, that means we also need to
 527             # check for pkg-config. Note that it is possible to use
 528             # protobuf without the involvement of pkg-config. Later on we
 529             # check go a library config check and at that point the test
 530             # will fail if libprotobuf cannot be found.
 531             if have_pkg_config:
 532                 try:
 533                     # Attempt to establish what linking flags to add for
 534                     # protobuf
 535                     # using pkg-config
 536                     main.ParseConfig(
 537                             'pkg-config --cflags --libs-only-L protobuf')
 538                 except:
 539                     warning('pkg-config could not get protobuf flags.')
 540 except Exception as e:
 541     warning('While checking protoc version:', str(e))
 542     main['HAVE_PROTOC'] = False
 543
 544 # Check for 'timeout' from GNU coreutils. If present, regressions will
 545 # be run with a time limit. We require version 8.13 since we rely on
 546 # support for the '--foreground' option.
 547 if sys.platform.startswith('freebsd'):
 548     timeout_lines = readCommand(['gtimeout', '--version'],
 549                                 exception='').splitlines()
 550 else:
 551     timeout_lines = readCommand(['timeout', '--version'],
 552                                 exception='').splitlines()
 553 # Get the first line and tokenize it
 554 timeout_version = timeout_lines[0].split() if timeout_lines else []
 555 main['TIMEOUT'] =  timeout_version and \
 556     compareVersions(timeout_version[-1], '8.13') >= 0
 557
 558 def CheckCxxFlag(context, flag):
 559     context.Message("Checking for compiler %s support... " % flag)
 560     last_cxxflags = context.env['CXXFLAGS']
 561     context.env.Append(CXXFLAGS=[flag])
 562     ret = context.TryCompile('', '.cc')
 563     context.env['CXXFLAGS'] = last_cxxflags
 564     context.Result(ret)
 565     return ret
 566
 567 def CheckLinkFlag(context, flag):
 568     context.Message("Checking for linker %s support... " % flag)
 569     last_linkflags = context.env['LINKFLAGS']
 570     context.env.Append(LINKFLAGS=[flag])
 571     ret = context.TryLink('int main(int, char *[]) { return 0; }', '.cc')
 572     context.env['LINKFLAGS'] = last_linkflags
 573     context.Result(ret)
 574     return ret
 575
 576 # Add a custom Check function to test for structure members.
 577 def CheckMember(context, include, decl, member, include_quotes="<>"):
 578     context.Message("Checking for member %s in %s..." %
 579                     (member, decl))
 580     text = """
 581 #include %(header)s
 582 int main(){
 583   %(decl)s test;
 584   (void)test.%(member)s;
 585   return 0;
 586 };
 587 """ % { "header" : include_quotes[0] + include + include_quotes[1],
 588         "decl" : decl,
 589         "member" : member,
 590         }
 591
 592     ret = context.TryCompile(text, extension=".cc")
 593     context.Result(ret)
 594     return ret
 595
 596 def CheckPythonLib(context):
 597     context.Message('Checking Python version... ')
 598     ret = context.TryRun(r"""
 599 #include <pybind11/embed.h>
 600
 601 int
 602 main(int argc, char **argv) {
 603     pybind11::scoped_interpreter guard{};
 604     pybind11::exec(
 605         "import sys\n"
 606         "vi = sys.version_info\n"
 607         "sys.stdout.write('%i.%i.%i' % (vi.major, vi.minor, vi.micro));\n");
 608     return 0;
 609 }
 610     """, extension=".cc")
 611     context.Result(ret[1] if ret[0] == 1 else 0)
 612     if ret[0] == 0:
 613         return None
 614     else:
 615         return tuple(map(int, ret[1].split(".")))
 616
 617 # Platform-specific configuration.  Note again that we assume that all
 618 # builds under a given build root run on the same host platform.
 619 conf = Configure(main,
 620                  conf_dir = joinpath(build_root, '.scons_config'),
 621                  log_file = joinpath(build_root, 'scons_config.log'),
 622                  custom_tests = {
 623         'CheckMember' : CheckMember,
 624         'CheckPythonLib' : CheckPythonLib,
 625         'CheckCxxFlag' : CheckCxxFlag,
 626         'CheckLinkFlag' : CheckLinkFlag,
 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 if not GetOption('no_compress_debug'):
 667     if conf.CheckCxxFlag('-gz'):
 668         main.Append(CXXFLAGS=['-gz'])
 669     else:
 670         warning("Can't enable object file debug section compression")
 671     if conf.CheckLinkFlag('-gz'):
 672         main.Append(LINKFLAGS=['-gz'], SHLINKFLAGS=['-gz'])
 673     else:
 674         warning("Can't enable executable debug section compression")
 675
 676 main['USE_PYTHON'] = not GetOption('without_python')
 677 if main['USE_PYTHON']:
 678     # Find Python include and library directories for embedding the
 679     # interpreter. We rely on python-config to resolve the appropriate
 680     # includes and linker flags. ParseConfig does not seem to understand
 681     # the more exotic linker flags such as -Xlinker and -export-dynamic so
 682     # we add them explicitly below. If you want to link in an alternate
 683     # version of python, see above for instructions on how to invoke
 684     # scons with the appropriate PATH set.
 685
 686     python_config = main.Detect(main['PYTHON_CONFIG'])
 687     if python_config is None:
 688         error("Can't find a suitable python-config, tried %s" % \
 689               main['PYTHON_CONFIG'])
 690
 691     print("Info: Using Python config: %s" % (python_config, ))
 692
 693     py_includes = readCommand([python_config, '--includes'],
 694                               exception='').split()
 695     py_includes = list(filter(
 696         lambda s: match(r'.*\/include\/.*',s), py_includes))
 697     # Strip the -I from the include folders before adding them to the
 698     # CPPPATH
 699     py_includes = list(map(
 700         lambda s: s[2:] if s.startswith('-I') else s, py_includes))
 701     main.Append(CPPPATH=py_includes)
 702
 703     # Read the linker flags and split them into libraries and other link
 704     # flags. The libraries are added later through the call the CheckLib.
 705     # Note: starting in Python 3.8 the --embed flag is required to get the
 706     # -lpython3.8 linker flag
 707     retcode, cmd_stdout = readCommandWithReturn(
 708         [python_config, '--ldflags', '--embed'], exception='')
 709     if retcode != 0:
 710         # If --embed isn't detected then we're running python <3.8
 711         retcode, cmd_stdout = readCommandWithReturn(
 712             [python_config, '--ldflags'], exception='')
 713
 714     # Checking retcode again
 715     if retcode != 0:
 716         error("Failing on python-config --ldflags command")
 717
 718     py_ld_flags = cmd_stdout.split()
 719
 720     py_libs = []
 721     for lib in py_ld_flags:
 722          if not lib.startswith('-l'):
 723              main.Append(LINKFLAGS=[lib])
 724          else:
 725              lib = lib[2:]
 726              if lib not in py_libs:
 727                  py_libs.append(lib)
 728
 729     # verify that this stuff works
 730     if not conf.CheckHeader('Python.h', '<>'):
 731         error("Check failed for Python.h header in",
 732                 ' '.join(py_includes), "\n"
 733               "Two possible reasons:\n"
 734               "1. Python headers are not installed (You can install the "
 735               "package python-dev on Ubuntu and RedHat)\n"
 736               "2. SCons is using a wrong C compiler. This can happen if "
 737               "CC has the wrong value.\n"
 738               "CC = %s" % main['CC'])
 739
 740     for lib in py_libs:
 741         if not conf.CheckLib(lib):
 742             error("Can't find library %s required by python." % lib)
 743
 744     main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
 745
 746     marshal_env = main.Clone()
 747
 748     # Bare minimum environment that only includes python
 749     marshal_env.Append(CCFLAGS='$MARSHAL_CCFLAGS_EXTRA')
 750     marshal_env.Append(LINKFLAGS='$MARSHAL_LDFLAGS_EXTRA')
 751
 752     py_version = conf.CheckPythonLib()
 753     if not py_version:
 754         error("Can't find a working Python installation")
 755
 756     # Found a working Python installation. Check if it meets minimum
 757     # requirements.
 758     if py_version[0] < 3 or \
 759     (py_version[0] == 3 and py_version[1] < 6):
 760         error('Python version too old. Version 3.6 or newer is required.')
 761     elif py_version[0] > 3:
 762         warning('Python version too new. Python 3 expected.')
 763
 764 # On Solaris you need to use libsocket for socket ops
 765 if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
 766    if not conf.CheckLibWithHeader('socket', 'sys/socket.h',
 767                                   'C++', 'accept(0,0,0);'):
 768        error("Can't find library with socket calls (e.g. accept()).")
 769
 770 # Check for zlib.  If the check passes, libz will be automatically
 771 # added to the LIBS environment variable.
 772 if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
 773     error('Did not find needed zlib compression library '
 774           'and/or zlib.h header file.\n'
 775           'Please install zlib and try again.')
 776
 777 # If we have the protobuf compiler, also make sure we have the
 778 # development libraries. If the check passes, libprotobuf will be
 779 # automatically added to the LIBS environment variable. After
 780 # this, we can use the HAVE_PROTOBUF flag to determine if we have
 781 # got both protoc and libprotobuf available.
 782 main['HAVE_PROTOBUF'] = main['HAVE_PROTOC'] and \
 783     conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
 784                             'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
 785
 786 # Valgrind gets much less confused if you tell it when you're using
 787 # alternative stacks.
 788 main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
 789
 790 # If we have the compiler but not the library, print another warning.
 791 if main['HAVE_PROTOC'] and not main['HAVE_PROTOBUF']:
 792     warning('Did not find protocol buffer library and/or headers.\n'
 793             'Please install libprotobuf-dev for tracing support.')
 794
 795 # Check for librt.
 796 have_posix_clock = \
 797     conf.CheckLibWithHeader(None, 'time.h', 'C',
 798                             'clock_nanosleep(0,0,NULL,NULL);') or \
 799     conf.CheckLibWithHeader('rt', 'time.h', 'C',
 800                             'clock_nanosleep(0,0,NULL,NULL);')
 801
 802 have_posix_timers = \
 803     conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
 804                             'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
 805
 806 if not GetOption('without_tcmalloc'):
 807     if conf.CheckLib('tcmalloc'):
 808         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 809     elif conf.CheckLib('tcmalloc_minimal'):
 810         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 811     else:
 812         warning("You can get a 12% performance improvement by "
 813                 "installing tcmalloc (libgoogle-perftools-dev package "
 814                 "on Ubuntu or RedHat).")
 815
 816
 817 # Detect back trace implementations. The last implementation in the
 818 # list will be used by default.
 819 backtrace_impls = [ "none" ]
 820
 821 backtrace_checker = 'char temp;' + \
 822     ' backtrace_symbols_fd((void*)&temp, 0, 0);'
 823 if conf.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker):
 824     backtrace_impls.append("glibc")
 825 elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
 826                              backtrace_checker):
 827     # NetBSD and FreeBSD need libexecinfo.
 828     backtrace_impls.append("glibc")
 829     main.Append(LIBS=['execinfo'])
 830
 831 if backtrace_impls[-1] == "none":
 832     default_backtrace_impl = "none"
 833     warning("No suitable back trace implementation found.")
 834
 835 if not have_posix_clock:
 836     warning("Can't find library for POSIX clocks.")
 837
 838 # Check for <fenv.h> (C99 FP environment control)
 839 have_fenv = conf.CheckHeader('fenv.h', '<>')
 840 if not have_fenv:
 841     warning("Header file <fenv.h> not found.\n"
 842             "This host has no IEEE FP rounding mode control.")
 843
 844 # Check for <png.h> (libpng library needed if wanting to dump
 845 # frame buffer image in png format)
 846 have_png = conf.CheckHeader('png.h', '<>')
 847 if not have_png:
 848     warning("Header file <png.h> not found.\n"
 849             "This host has no libpng library.\n"
 850             "Disabling support for PNG framebuffers.")
 851
 852 # Check if we should enable KVM-based hardware virtualization. The API
 853 # we rely on exists since version 2.6.36 of the kernel, but somehow
 854 # the KVM_API_VERSION does not reflect the change. We test for one of
 855 # the types as a fall back.
 856 have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
 857 if not have_kvm:
 858     print("Info: Compatible header file <linux/kvm.h> not found, "
 859           "disabling KVM support.")
 860
 861 # Check if the TUN/TAP driver is available.
 862 have_tuntap = conf.CheckHeader('linux/if_tun.h', '<>')
 863 if not have_tuntap:
 864     print("Info: Compatible header file <linux/if_tun.h> not found.")
 865
 866 # x86 needs support for xsave. We test for the structure here since we
 867 # won't be able to run new tests by the time we know which ISA we're
 868 # targeting.
 869 have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
 870                                     '#include <linux/kvm.h>') != 0
 871
 872 # Check if the requested target ISA is compatible with the host
 873 def is_isa_kvm_compatible(isa):
 874     try:
 875         import platform
 876         host_isa = platform.machine()
 877     except:
 878         warning("Failed to determine host ISA.")
 879         return False
 880
 881     if not have_posix_timers:
 882         warning("Can not enable KVM, host seems to lack support "
 883                 "for POSIX timers")
 884         return False
 885
 886     if isa == "arm":
 887         return host_isa in ( "armv7l", "aarch64" )
 888     elif isa == "x86":
 889         if host_isa != "x86_64":
 890             return False
 891
 892         if not have_kvm_xsave:
 893             warning("KVM on x86 requires xsave support in kernel headers.")
 894             return False
 895
 896         return True
 897     else:
 898         return False
 899
 900
 901 # Check if the exclude_host attribute is available. We want this to
 902 # get accurate instruction counts in KVM.
 903 main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
 904     'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
 905
 906 def check_hdf5():
 907     return \
 908         conf.CheckLibWithHeader('hdf5', 'hdf5.h', 'C',
 909                                 'H5Fcreate("", 0, 0, 0);') and \
 910         conf.CheckLibWithHeader('hdf5_cpp', 'H5Cpp.h', 'C++',
 911                                 'H5::H5File("", 0);')
 912
 913 def check_hdf5_pkg(name):
 914     print("Checking for %s using pkg-config..." % name, end="")
 915     if not have_pkg_config:
 916         print(" pkg-config not found")
 917         return False
 918
 919     try:
 920         main.ParseConfig('pkg-config --cflags-only-I --libs-only-L %s' % name)
 921         print(" yes")
 922         return True
 923     except:
 924         print(" no")
 925         return False
 926
 927 # Check if there is a pkg-config configuration for hdf5. If we find
 928 # it, setup the environment to enable linking and header inclusion. We
 929 # don't actually try to include any headers or link with hdf5 at this
 930 # stage.
 931 if not check_hdf5_pkg('hdf5-serial'):
 932     check_hdf5_pkg('hdf5')
 933
 934 # Check if the HDF5 libraries can be found. This check respects the
 935 # include path and library path provided by pkg-config. We perform
 936 # this check even if there isn't a pkg-config configuration for hdf5
 937 # since some installations don't use pkg-config.
 938 have_hdf5 = check_hdf5()
 939 if not have_hdf5:
 940     print("Warning: Couldn't find any HDF5 C++ libraries. Disabling")
 941     print("         HDF5 support.")
 942
 943 ######################################################################
 944 #
 945 # Finish the configuration
 946 #
 947 main = conf.Finish()
 948
 949 ######################################################################
 950 #
 951 # Collect all non-global variables
 952 #
 953
 954 # Define the universe of supported ISAs
 955 all_isa_list = [ ]
 956 all_gpu_isa_list = [ ]
 957 Export('all_isa_list')
 958 Export('all_gpu_isa_list')
 959
 960 class CpuModel(object):
 961     '''The CpuModel class encapsulates everything the ISA parser needs to
 962     know about a particular CPU model.'''
 963
 964     # Dict of available CPU model objects.  Accessible as CpuModel.dict.
 965     dict = {}
 966
 967     # Constructor.  Automatically adds models to CpuModel.dict.
 968     def __init__(self, name, default=False):
 969         self.name = name           # name of model
 970
 971         # This cpu is enabled by default
 972         self.default = default
 973
 974         # Add self to dict
 975         if name in CpuModel.dict:
 976             raise AttributeError("CpuModel '%s' already registered" % name)
 977         CpuModel.dict[name] = self
 978
 979 Export('CpuModel')
 980
 981 # Sticky variables get saved in the variables file so they persist from
 982 # one invocation to the next (unless overridden, in which case the new
 983 # value becomes sticky).
 984 sticky_vars = Variables(args=ARGUMENTS)
 985 Export('sticky_vars')
 986
 987 # Sticky variables that should be exported
 988 export_vars = []
 989 Export('export_vars')
 990
 991 # For Ruby
 992 all_protocols = []
 993 Export('all_protocols')
 994 protocol_dirs = []
 995 Export('protocol_dirs')
 996 slicc_includes = []
 997 Export('slicc_includes')
 998
 999 # Walk the tree and execute all SConsopts scripts that wil add to the
1000 # above variables
1001 if GetOption('verbose'):
1002     print("Reading SConsopts")
1003 for bdir in [ base_dir ] + extras_dir_list:
1004     if not isdir(bdir):
1005         error("Directory '%s' does not exist." % bdir)
1006     for root, dirs, files in os.walk(bdir):
1007         if 'SConsopts' in files:
1008             if GetOption('verbose'):
1009                 print("Reading", joinpath(root, 'SConsopts'))
1010             SConscript(joinpath(root, 'SConsopts'))
1011
1012 all_isa_list.sort()
1013 all_gpu_isa_list.sort()
1014
1015 sticky_vars.AddVariables(
1016     EnumVariable('TARGET_ISA', 'Target ISA', 'null', all_isa_list),
1017     EnumVariable('TARGET_GPU_ISA', 'Target GPU ISA', 'gcn3', all_gpu_isa_list),
1018     ListVariable('CPU_MODELS', 'CPU models',
1019                  sorted(n for n,m in CpuModel.dict.items() if m.default),
1020                  sorted(CpuModel.dict.keys())),
1021     BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
1022                  False),
1023     BoolVariable('USE_SSE2',
1024                  'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
1025                  False),
1026     BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
1027     BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
1028     BoolVariable('USE_PNG',  'Enable support for PNG images', have_png),
1029     BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models',
1030                  have_kvm),
1031     BoolVariable('USE_TUNTAP',
1032                  'Enable using a tap device to bridge to the host network',
1033                  have_tuntap),
1034     BoolVariable('BUILD_GPU', 'Build the compute-GPU model', False),
1035     EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1036                   all_protocols),
1037     EnumVariable('BACKTRACE_IMPL', 'Post-mortem dump implementation',
1038                  backtrace_impls[-1], backtrace_impls),
1039     ('NUMBER_BITS_PER_SET', 'Max elements in set (default 64)',
1040                  64),
1041     BoolVariable('USE_HDF5', 'Enable the HDF5 support', have_hdf5),
1042     )
1043
1044 # These variables get exported to #defines in config/*.hh (see src/SConscript).
1045 export_vars += ['USE_FENV', 'TARGET_ISA', 'TARGET_GPU_ISA',
1046                 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP', 'PROTOCOL',
1047                 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
1048                 'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG',
1049                 'NUMBER_BITS_PER_SET', 'USE_HDF5']
1050
1051 ###################################################
1052 #
1053 # Define a SCons builder for configuration flag headers.
1054 #
1055 ###################################################
1056
1057 # This function generates a config header file that #defines the
1058 # variable symbol to the current variable setting (0 or 1).  The source
1059 # operands are the name of the variable and a Value node containing the
1060 # value of the variable.
1061 def build_config_file(target, source, env):
1062     (variable, value) = [s.get_contents().decode('utf-8') for s in source]
1063     with open(str(target[0].abspath), 'w') as f:
1064         print('#define', variable, value, file=f)
1065     return None
1066
1067 # Combine the two functions into a scons Action object.
1068 config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1069
1070 # The emitter munges the source & target node lists to reflect what
1071 # we're really doing.
1072 def config_emitter(target, source, env):
1073     # extract variable name from Builder arg
1074     variable = str(target[0])
1075     # True target is config header file
1076     target = Dir('config').File(variable.lower() + '.hh')
1077     val = env[variable]
1078     if isinstance(val, bool):
1079         # Force value to 0/1
1080         val = int(val)
1081     elif isinstance(val, str):
1082         val = '"' + val + '"'
1083
1084     # Sources are variable name & value (packaged in SCons Value nodes)
1085     return [target], [Value(variable), Value(val)]
1086
1087 config_builder = Builder(emitter=config_emitter, action=config_action)
1088
1089 main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1090
1091 ###################################################
1092 #
1093 # Builders for static and shared partially linked object files.
1094 #
1095 ###################################################
1096
1097 partial_static_builder = Builder(action=SCons.Defaults.LinkAction,
1098                                  src_suffix='$OBJSUFFIX',
1099                                  src_builder=['StaticObject', 'Object'],
1100                                  LINKFLAGS='$PLINKFLAGS',
1101                                  LIBS='')
1102
1103 def partial_shared_emitter(target, source, env):
1104     for tgt in target:
1105         tgt.attributes.shared = 1
1106     return (target, source)
1107 partial_shared_builder = Builder(action=SCons.Defaults.ShLinkAction,
1108                                  emitter=partial_shared_emitter,
1109                                  src_suffix='$SHOBJSUFFIX',
1110                                  src_builder='SharedObject',
1111                                  SHLINKFLAGS='$PSHLINKFLAGS',
1112                                  LIBS='')
1113
1114 main.Append(BUILDERS = { 'PartialShared' : partial_shared_builder,
1115                          'PartialStatic' : partial_static_builder })
1116
1117 def add_local_rpath(env, *targets):
1118     '''Set up an RPATH for a library which lives in the build directory.
1119
1120     The construction environment variable BIN_RPATH_PREFIX should be set to
1121     the relative path of the build directory starting from the location of the
1122     binary.'''
1123     for target in targets:
1124         target = env.Entry(target)
1125         if not isinstance(target, SCons.Node.FS.Dir):
1126             target = target.dir
1127         relpath = os.path.relpath(target.abspath, env['BUILDDIR'])
1128         components = [
1129             '\\$$ORIGIN',
1130             '${BIN_RPATH_PREFIX}',
1131             relpath
1132         ]
1133         env.Append(RPATH=[env.Literal(os.path.join(*components))])
1134
1135 if sys.platform != "darwin":
1136     main.Append(LINKFLAGS=Split('-z origin'))
1137
1138 main.AddMethod(add_local_rpath, 'AddLocalRPATH')
1139
1140 # builds in ext are shared across all configs in the build root.
1141 ext_dir = Dir('#ext').abspath
1142 ext_build_dirs = []
1143 for root, dirs, files in os.walk(ext_dir):
1144     if 'SConscript' in files:
1145         build_dir = os.path.relpath(root, ext_dir)
1146         ext_build_dirs.append(build_dir)
1147         main.SConscript(joinpath(root, 'SConscript'),
1148                         variant_dir=joinpath(build_root, build_dir))
1149
1150 gdb_xml_dir = joinpath(ext_dir, 'gdb-xml')
1151 Export('gdb_xml_dir')
1152
1153 ###################################################
1154 #
1155 # This builder and wrapper method are used to set up a directory with
1156 # switching headers. Those are headers which are in a generic location and
1157 # that include more specific headers from a directory chosen at build time
1158 # based on the current build settings.
1159 #
1160 ###################################################
1161
1162 def build_switching_header(target, source, env):
1163     path = str(target[0])
1164     subdir = str(source[0])
1165     dp, fp = os.path.split(path)
1166     dp = os.path.relpath(os.path.realpath(dp),
1167                          os.path.realpath(env['BUILDDIR']))
1168     with open(path, 'w') as hdr:
1169         print('#include "%s/%s/%s"' % (dp, subdir, fp), file=hdr)
1170
1171 switching_header_action = MakeAction(build_switching_header,
1172                                      Transform('GENERATE'))
1173
1174 switching_header_builder = Builder(action=switching_header_action,
1175                                    source_factory=Value,
1176                                    single_source=True)
1177
1178 main.Append(BUILDERS = { 'SwitchingHeader': switching_header_builder })
1179
1180 def switching_headers(self, headers, source):
1181     for header in headers:
1182         self.SwitchingHeader(header, source)
1183
1184 main.AddMethod(switching_headers, 'SwitchingHeaders')
1185
1186 ###################################################
1187 #
1188 # Define build environments for selected configurations.
1189 #
1190 ###################################################
1191
1192 for variant_path in variant_paths:
1193     if not GetOption('silent'):
1194         print("Building in", variant_path)
1195
1196     # Make a copy of the build-root environment to use for this config.
1197     env = main.Clone()
1198     env['BUILDDIR'] = variant_path
1199
1200     # variant_dir is the tail component of build path, and is used to
1201     # determine the build parameters (e.g., 'X86')
1202     (build_root, variant_dir) = splitpath(variant_path)
1203
1204     # Set env variables according to the build directory config.
1205     sticky_vars.files = []
1206     # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1207     # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1208     # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1209     current_vars_file = joinpath(build_root, 'variables', variant_dir)
1210     if isfile(current_vars_file):
1211         sticky_vars.files.append(current_vars_file)
1212         if not GetOption('silent'):
1213             print("Using saved variables file %s" % current_vars_file)
1214     elif variant_dir in ext_build_dirs:
1215         # Things in ext are built without a variant directory.
1216         continue
1217     else:
1218         # Build dir-specific variables file doesn't exist.
1219
1220         # Make sure the directory is there so we can create it later
1221         opt_dir = dirname(current_vars_file)
1222         if not isdir(opt_dir):
1223             mkdir(opt_dir)
1224
1225         # Get default build variables from source tree.  Variables are
1226         # normally determined by name of $VARIANT_DIR, but can be
1227         # overridden by '--default=' arg on command line.
1228         default = GetOption('default')
1229         opts_dir = Dir('#build_opts').abspath
1230         if default:
1231             default_vars_files = [joinpath(build_root, 'variables', default),
1232                                   joinpath(opts_dir, default)]
1233         else:
1234             default_vars_files = [joinpath(opts_dir, variant_dir)]
1235         existing_files = list(filter(isfile, default_vars_files))
1236         if existing_files:
1237             default_vars_file = existing_files[0]
1238             sticky_vars.files.append(default_vars_file)
1239             print("Variables file %s not found,\n  using defaults in %s"
1240                   % (current_vars_file, default_vars_file))
1241         else:
1242             error("Cannot find variables file %s or default file(s) %s"
1243                   % (current_vars_file, ' or '.join(default_vars_files)))
1244             Exit(1)
1245
1246     # Apply current variable settings to env
1247     sticky_vars.Update(env)
1248
1249     Help('''
1250 Build variables for {dir}:
1251 {help}
1252 '''.format(dir=variant_dir, help=sticky_vars.GenerateHelpText(env)),
1253          append=True)
1254
1255     # Process variable settings.
1256
1257     if not have_fenv and env['USE_FENV']:
1258         warning("<fenv.h> not available; forcing USE_FENV to False in",
1259                 variant_dir + ".")
1260         env['USE_FENV'] = False
1261
1262     if not env['USE_FENV']:
1263         warning("No IEEE FP rounding mode control in", variant_dir + ".\n"
1264                 "FP results may deviate slightly from other platforms.")
1265
1266     if not have_png and env['USE_PNG']:
1267         warning("<png.h> not available; forcing USE_PNG to False in",
1268                 variant_dir + ".")
1269         env['USE_PNG'] = False
1270
1271     if env['USE_PNG']:
1272         env.Append(LIBS=['png'])
1273
1274     if env['EFENCE']:
1275         env.Append(LIBS=['efence'])
1276
1277     if env['USE_KVM']:
1278         if not have_kvm:
1279             warning("Can not enable KVM, host seems to lack KVM support")
1280             env['USE_KVM'] = False
1281         elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1282             print("Info: KVM support disabled due to unsupported host and "
1283                   "target ISA combination")
1284             env['USE_KVM'] = False
1285
1286     if env['USE_TUNTAP']:
1287         if not have_tuntap:
1288             warning("Can't connect EtherTap with a tap device.")
1289             env['USE_TUNTAP'] = False
1290
1291     if env['BUILD_GPU']:
1292         env.Append(CPPDEFINES=['BUILD_GPU'])
1293
1294     # Warn about missing optional functionality
1295     if env['USE_KVM']:
1296         if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1297             warning("perf_event headers lack support for the exclude_host "
1298                     "attribute. KVM instruction counts will be inaccurate.")
1299
1300     # Save sticky variable settings back to current variables file
1301     sticky_vars.Save(current_vars_file, env)
1302
1303     if env['USE_SSE2']:
1304         env.Append(CCFLAGS=['-msse2'])
1305
1306     env.Append(CCFLAGS='$CCFLAGS_EXTRA')
1307     env.Append(LINKFLAGS='$LDFLAGS_EXTRA')
1308
1309     exports=['env']
1310     if main['USE_PYTHON']:
1311         exports.append('marshal_env')
1312
1313     # The src/SConscript file sets up the build rules in 'env' according
1314     # to the configured variables.  It returns a list of environments,
1315     # one for each variant build (debug, opt, etc.)
1316     SConscript('src/SConscript', variant_dir=variant_path, exports=exports)
1317
1318 atexit.register(summarize_warnings)