SConstruct

   1 # -*- mode:python -*-
   2
   3 # Copyright (c) 2013, 2015-2019 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 # Authors: Steve Reinhardt
  44 #          Nathan Binkert
  45
  46 ###################################################
  47 #
  48 # SCons top-level build description (SConstruct) file.
  49 #
  50 # While in this directory ('gem5'), just type 'scons' to build the default
  51 # configuration (see below), or type 'scons build/<CONFIG>/<binary>'
  52 # to build some other configuration (e.g., 'build/ALPHA/gem5.opt' for
  53 # the optimized full-system version).
  54 #
  55 # You can build gem5 in a different directory as long as there is a
  56 # 'build/<CONFIG>' somewhere along the target path.  The build system
  57 # expects that all configs under the same build directory are being
  58 # built for the same host system.
  59 #
  60 # Examples:
  61 #
  62 #   The following two commands are equivalent.  The '-u' option tells
  63 #   scons to search up the directory tree for this SConstruct file.
  64 #   % cd <path-to-src>/gem5 ; scons build/ALPHA/gem5.debug
  65 #   % cd <path-to-src>/gem5/build/ALPHA; scons -u gem5.debug
  66 #
  67 #   The following two commands are equivalent and demonstrate building
  68 #   in a directory outside of the source tree.  The '-C' option tells
  69 #   scons to chdir to the specified directory to find this SConstruct
  70 #   file.
  71 #   % cd <path-to-src>/gem5 ; scons /local/foo/build/ALPHA/gem5.debug
  72 #   % cd /local/foo/build/ALPHA; scons -C <path-to-src>/gem5 gem5.debug
  73 #
  74 # You can use 'scons -H' to print scons options.  If you're in this
  75 # 'gem5' directory (or use -u or -C to tell scons where to find this
  76 # file), you can use 'scons -h' to print all the gem5-specific build
  77 # options as well.
  78 #
  79 ###################################################
  80
  81 from __future__ import print_function
  82
  83 # Global Python includes
  84 import itertools
  85 import os
  86 import re
  87 import shutil
  88 import subprocess
  89 import sys
  90
  91 from os import mkdir, environ
  92 from os.path import abspath, basename, dirname, expanduser, normpath
  93 from os.path import exists,  isdir, isfile
  94 from os.path import join as joinpath, split as splitpath
  95 from re import match
  96
  97 # SCons includes
  98 import SCons
  99 import SCons.Node
 100 import SCons.Node.FS
 101
 102 from m5.util import compareVersions, readCommand
 103
 104 help_texts = {
 105     "options" : "",
 106     "global_vars" : "",
 107     "local_vars" : ""
 108 }
 109
 110 Export("help_texts")
 111
 112
 113 # There's a bug in scons in that (1) by default, the help texts from
 114 # AddOption() are supposed to be displayed when you type 'scons -h'
 115 # and (2) you can override the help displayed by 'scons -h' using the
 116 # Help() function, but these two features are incompatible: once
 117 # you've overridden the help text using Help(), there's no way to get
 118 # at the help texts from AddOptions.  See:
 119 #     http://scons.tigris.org/issues/show_bug.cgi?id=2356
 120 #     http://scons.tigris.org/issues/show_bug.cgi?id=2611
 121 # This hack lets us extract the help text from AddOptions and
 122 # re-inject it via Help().  Ideally someday this bug will be fixed and
 123 # we can just use AddOption directly.
 124 def AddLocalOption(*args, **kwargs):
 125     col_width = 30
 126
 127     help = "  " + ", ".join(args)
 128     if "help" in kwargs:
 129         length = len(help)
 130         if length >= col_width:
 131             help += "\n" + " " * col_width
 132         else:
 133             help += " " * (col_width - length)
 134         help += kwargs["help"]
 135     help_texts["options"] += help + "\n"
 136
 137     AddOption(*args, **kwargs)
 138
 139 AddLocalOption('--colors', dest='use_colors', action='store_true',
 140                help="Add color to abbreviated scons output")
 141 AddLocalOption('--no-colors', dest='use_colors', action='store_false',
 142                help="Don't add color to abbreviated scons output")
 143 AddLocalOption('--with-cxx-config', dest='with_cxx_config',
 144                action='store_true',
 145                help="Build with support for C++-based configuration")
 146 AddLocalOption('--default', dest='default', type='string', action='store',
 147                help='Override which build_opts file to use for defaults')
 148 AddLocalOption('--ignore-style', dest='ignore_style', action='store_true',
 149                help='Disable style checking hooks')
 150 AddLocalOption('--gold-linker', dest='gold_linker', action='store_true',
 151                help='Use the gold linker')
 152 AddLocalOption('--no-lto', dest='no_lto', action='store_true',
 153                help='Disable Link-Time Optimization for fast')
 154 AddLocalOption('--force-lto', dest='force_lto', action='store_true',
 155                help='Use Link-Time Optimization instead of partial linking' +
 156                     ' when the compiler doesn\'t support using them together.')
 157 AddLocalOption('--update-ref', dest='update_ref', action='store_true',
 158                help='Update test reference outputs')
 159 AddLocalOption('--verbose', dest='verbose', action='store_true',
 160                help='Print full tool command lines')
 161 AddLocalOption('--without-python', dest='without_python',
 162                action='store_true',
 163                help='Build without Python configuration support')
 164 AddLocalOption('--without-tcmalloc', dest='without_tcmalloc',
 165                action='store_true',
 166                help='Disable linking against tcmalloc')
 167 AddLocalOption('--with-ubsan', dest='with_ubsan', action='store_true',
 168                help='Build with Undefined Behavior Sanitizer if available')
 169 AddLocalOption('--with-asan', dest='with_asan', action='store_true',
 170                help='Build with Address Sanitizer if available')
 171
 172 if GetOption('no_lto') and GetOption('force_lto'):
 173     print('--no-lto and --force-lto are mutually exclusive')
 174     Exit(1)
 175
 176 ########################################################################
 177 #
 178 # Set up the main build environment.
 179 #
 180 ########################################################################
 181
 182 main = Environment()
 183
 184 from gem5_scons import Transform
 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     print("No C++ compiler installed (package g++ on Ubuntu and RedHat)")
 193     Exit(1)
 194
 195 ###################################################
 196 #
 197 # Figure out which configurations to set up based on the path(s) of
 198 # the target(s).
 199 #
 200 ###################################################
 201
 202 # Find default configuration & binary.
 203 Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))
 204
 205 # helper function: find last occurrence of element in list
 206 def rfind(l, elt, offs = -1):
 207     for i in range(len(l)+offs, 0, -1):
 208         if l[i] == elt:
 209             return i
 210     raise ValueError, "element not found"
 211
 212 # Take a list of paths (or SCons Nodes) and return a list with all
 213 # paths made absolute and ~-expanded.  Paths will be interpreted
 214 # relative to the launch directory unless a different root is provided
 215 def makePathListAbsolute(path_list, root=GetLaunchDir()):
 216     return [abspath(joinpath(root, expanduser(str(p))))
 217             for p in path_list]
 218
 219 def find_first_prog(prog_names):
 220     """Find the absolute path to the first existing binary in prog_names"""
 221
 222     if not isinstance(prog_names, (list, tuple)):
 223         prog_names = [ prog_names ]
 224
 225     for p in prog_names:
 226         p = main.WhereIs(p)
 227         if p is not None:
 228             return p
 229
 230     return None
 231
 232 # Each target must have 'build' in the interior of the path; the
 233 # directory below this will determine the build parameters.  For
 234 # example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
 235 # recognize that ALPHA_SE specifies the configuration because it
 236 # follow 'build' in the build path.
 237
 238 # The funky assignment to "[:]" is needed to replace the list contents
 239 # in place rather than reassign the symbol to a new list, which
 240 # doesn't work (obviously!).
 241 BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
 242
 243 # Generate a list of the unique build roots and configs that the
 244 # collected targets reference.
 245 variant_paths = []
 246 build_root = None
 247 for t in BUILD_TARGETS:
 248     path_dirs = t.split('/')
 249     try:
 250         build_top = rfind(path_dirs, 'build', -2)
 251     except:
 252         print("Error: no non-leaf 'build' dir found on target path", t)
 253         Exit(1)
 254     this_build_root = joinpath('/',*path_dirs[:build_top+1])
 255     if not build_root:
 256         build_root = this_build_root
 257     else:
 258         if this_build_root != build_root:
 259             print("Error: build targets not under same build root\n"
 260                   "  %s\n  %s" % (build_root, this_build_root))
 261             Exit(1)
 262     variant_path = joinpath('/',*path_dirs[:build_top+2])
 263     if variant_path not in variant_paths:
 264         variant_paths.append(variant_path)
 265
 266 # Make sure build_root exists (might not if this is the first build there)
 267 if not isdir(build_root):
 268     mkdir(build_root)
 269 main['BUILDROOT'] = build_root
 270
 271 Export('main')
 272
 273 main.SConsignFile(joinpath(build_root, "sconsign"))
 274
 275 # Default duplicate option is to use hard links, but this messes up
 276 # when you use emacs to edit a file in the target dir, as emacs moves
 277 # file to file~ then copies to file, breaking the link.  Symbolic
 278 # (soft) links work better.
 279 main.SetOption('duplicate', 'soft-copy')
 280
 281 #
 282 # Set up global sticky variables... these are common to an entire build
 283 # tree (not specific to a particular build like ALPHA_SE)
 284 #
 285
 286 global_vars_file = joinpath(build_root, 'variables.global')
 287
 288 global_vars = Variables(global_vars_file, args=ARGUMENTS)
 289
 290 global_vars.AddVariables(
 291     ('CC', 'C compiler', environ.get('CC', main['CC'])),
 292     ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
 293     ('CCFLAGS_EXTRA', 'Extra C and C++ compiler flags', ''),
 294     ('LDFLAGS_EXTRA', 'Extra linker flags', ''),
 295     ('PYTHON_CONFIG', 'Python config binary to use',
 296      [ 'python2.7-config', 'python-config' ]),
 297     ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
 298     ('BATCH', 'Use batch pool for build and tests', False),
 299     ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
 300     ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
 301     ('EXTRAS', 'Add extra directories to the compilation', '')
 302     )
 303
 304 # Update main environment with values from ARGUMENTS & global_vars_file
 305 global_vars.Update(main)
 306 help_texts["global_vars"] += global_vars.GenerateHelpText(main)
 307
 308 # Save sticky variable settings back to current variables file
 309 global_vars.Save(global_vars_file, main)
 310
 311 # Parse EXTRAS variable to build list of all directories where we're
 312 # look for sources etc.  This list is exported as extras_dir_list.
 313 base_dir = main.srcdir.abspath
 314 if main['EXTRAS']:
 315     extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
 316 else:
 317     extras_dir_list = []
 318
 319 Export('base_dir')
 320 Export('extras_dir_list')
 321
 322 # the ext directory should be on the #includes path
 323 main.Append(CPPPATH=[Dir('ext')])
 324
 325 # Add shared top-level headers
 326 main.Prepend(CPPPATH=Dir('include'))
 327
 328 if GetOption('verbose'):
 329     def MakeAction(action, string, *args, **kwargs):
 330         return Action(action, *args, **kwargs)
 331 else:
 332     MakeAction = Action
 333     main['CCCOMSTR']        = Transform("CC")
 334     main['CXXCOMSTR']       = Transform("CXX")
 335     main['ASCOMSTR']        = Transform("AS")
 336     main['ARCOMSTR']        = Transform("AR", 0)
 337     main['LINKCOMSTR']      = Transform("LINK", 0)
 338     main['SHLINKCOMSTR']    = Transform("SHLINK", 0)
 339     main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
 340     main['M4COMSTR']        = Transform("M4")
 341     main['SHCCCOMSTR']      = Transform("SHCC")
 342     main['SHCXXCOMSTR']     = Transform("SHCXX")
 343 Export('MakeAction')
 344
 345 # Initialize the Link-Time Optimization (LTO) flags
 346 main['LTO_CCFLAGS'] = []
 347 main['LTO_LDFLAGS'] = []
 348
 349 # According to the readme, tcmalloc works best if the compiler doesn't
 350 # assume that we're using the builtin malloc and friends. These flags
 351 # are compiler-specific, so we need to set them after we detect which
 352 # compiler we're using.
 353 main['TCMALLOC_CCFLAGS'] = []
 354
 355 CXX_version = readCommand([main['CXX'],'--version'], exception=False)
 356 CXX_V = readCommand([main['CXX'],'-V'], exception=False)
 357
 358 main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
 359 main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
 360 if main['GCC'] + main['CLANG'] > 1:
 361     print('Error: How can we have two at the same time?')
 362     Exit(1)
 363
 364 # Set up default C++ compiler flags
 365 if main['GCC'] or main['CLANG']:
 366     # As gcc and clang share many flags, do the common parts here
 367     main.Append(CCFLAGS=['-pipe'])
 368     main.Append(CCFLAGS=['-fno-strict-aliasing'])
 369     # Enable -Wall and -Wextra and then disable the few warnings that
 370     # we consistently violate
 371     main.Append(CCFLAGS=['-Wall', '-Wundef', '-Wextra',
 372                          '-Wno-sign-compare', '-Wno-unused-parameter'])
 373     # We always compile using C++11
 374     main.Append(CXXFLAGS=['-std=c++11'])
 375     if sys.platform.startswith('freebsd'):
 376         main.Append(CCFLAGS=['-I/usr/local/include'])
 377         main.Append(CXXFLAGS=['-I/usr/local/include'])
 378
 379     main['FILTER_PSHLINKFLAGS'] = lambda x: str(x).replace(' -shared', '')
 380     main['PSHLINKFLAGS'] = main.subst('${FILTER_PSHLINKFLAGS(SHLINKFLAGS)}')
 381     if GetOption('gold_linker'):
 382         main.Append(LINKFLAGS='-fuse-ld=gold')
 383     main['PLINKFLAGS'] = main.subst('${LINKFLAGS}')
 384     shared_partial_flags = ['-r', '-nostdlib']
 385     main.Append(PSHLINKFLAGS=shared_partial_flags)
 386     main.Append(PLINKFLAGS=shared_partial_flags)
 387
 388     # Treat warnings as errors but white list some warnings that we
 389     # want to allow (e.g., deprecation warnings).
 390     main.Append(CCFLAGS=['-Werror',
 391                          '-Wno-error=deprecated-declarations',
 392                          '-Wno-error=deprecated',
 393                         ])
 394 else:
 395     print(termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal, end=' ')
 396     print("Don't know what compiler options to use for your compiler.")
 397     print(termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX'])
 398     print(termcap.Yellow + '       version:' + termcap.Normal, end = ' ')
 399     if not CXX_version:
 400         print(termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +
 401               termcap.Normal)
 402     else:
 403         print(CXX_version.replace('\n', '<nl>'))
 404     print("       If you're trying to use a compiler other than GCC")
 405     print("       or clang, there appears to be something wrong with your")
 406     print("       environment.")
 407     print("       ")
 408     print("       If you are trying to use a compiler other than those listed")
 409     print("       above you will need to ease fix SConstruct and ")
 410     print("       src/SConscript to support that compiler.")
 411     Exit(1)
 412
 413 if main['GCC']:
 414     # Check for a supported version of gcc. >= 4.8 is chosen for its
 415     # level of c++11 support. See
 416     # http://gcc.gnu.org/projects/cxx0x.html for details.
 417     gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
 418     if compareVersions(gcc_version, "4.8") < 0:
 419         print('Error: gcc version 4.8 or newer required.')
 420         print('       Installed version: ', gcc_version)
 421         Exit(1)
 422
 423     main['GCC_VERSION'] = gcc_version
 424
 425     if compareVersions(gcc_version, '4.9') >= 0:
 426         # Incremental linking with LTO is currently broken in gcc versions
 427         # 4.9 and above. A version where everything works completely hasn't
 428         # yet been identified.
 429         #
 430         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548
 431         main['BROKEN_INCREMENTAL_LTO'] = True
 432     if compareVersions(gcc_version, '6.0') >= 0:
 433         # gcc versions 6.0 and greater accept an -flinker-output flag which
 434         # selects what type of output the linker should generate. This is
 435         # necessary for incremental lto to work, but is also broken in
 436         # current versions of gcc. It may not be necessary in future
 437         # versions. We add it here since it might be, and as a reminder that
 438         # it exists. It's excluded if lto is being forced.
 439         #
 440         # https://gcc.gnu.org/gcc-6/changes.html
 441         # https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03161.html
 442         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69866
 443         if not GetOption('force_lto'):
 444             main.Append(PSHLINKFLAGS='-flinker-output=rel')
 445             main.Append(PLINKFLAGS='-flinker-output=rel')
 446
 447     # Make sure we warn if the user has requested to compile with the
 448     # Undefined Benahvior Sanitizer and this version of gcc does not
 449     # support it.
 450     if GetOption('with_ubsan') and \
 451             compareVersions(gcc_version, '4.9') < 0:
 452         print(termcap.Yellow + termcap.Bold +
 453             'Warning: UBSan is only supported using gcc 4.9 and later.' +
 454             termcap.Normal)
 455
 456     disable_lto = GetOption('no_lto')
 457     if not disable_lto and main.get('BROKEN_INCREMENTAL_LTO', False) and \
 458             not GetOption('force_lto'):
 459         print(termcap.Yellow + termcap.Bold +
 460             'Warning: Your compiler doesn\'t support incremental linking' +
 461             ' and lto at the same time, so lto is being disabled. To force' +
 462             ' lto on anyway, use the --force-lto option. That will disable' +
 463             ' partial linking.' +
 464             termcap.Normal)
 465         disable_lto = True
 466
 467     # Add the appropriate Link-Time Optimization (LTO) flags
 468     # unless LTO is explicitly turned off. Note that these flags
 469     # are only used by the fast target.
 470     if not disable_lto:
 471         # Pass the LTO flag when compiling to produce GIMPLE
 472         # output, we merely create the flags here and only append
 473         # them later
 474         main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 475
 476         # Use the same amount of jobs for LTO as we are running
 477         # scons with
 478         main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 479
 480     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
 481                                   '-fno-builtin-realloc', '-fno-builtin-free'])
 482
 483     # The address sanitizer is available for gcc >= 4.8
 484     if GetOption('with_asan'):
 485         if GetOption('with_ubsan') and \
 486                 compareVersions(main['GCC_VERSION'], '4.9') >= 0:
 487             main.Append(CCFLAGS=['-fsanitize=address,undefined',
 488                                  '-fno-omit-frame-pointer'],
 489                         LINKFLAGS='-fsanitize=address,undefined')
 490         else:
 491             main.Append(CCFLAGS=['-fsanitize=address',
 492                                  '-fno-omit-frame-pointer'],
 493                         LINKFLAGS='-fsanitize=address')
 494     # Only gcc >= 4.9 supports UBSan, so check both the version
 495     # and the command-line option before adding the compiler and
 496     # linker flags.
 497     elif GetOption('with_ubsan') and \
 498             compareVersions(main['GCC_VERSION'], '4.9') >= 0:
 499         main.Append(CCFLAGS='-fsanitize=undefined')
 500         main.Append(LINKFLAGS='-fsanitize=undefined')
 501
 502 elif main['CLANG']:
 503     # Check for a supported version of clang, >= 3.1 is needed to
 504     # support similar features as gcc 4.8. See
 505     # http://clang.llvm.org/cxx_status.html for details
 506     clang_version_re = re.compile(".* version (\d+\.\d+)")
 507     clang_version_match = clang_version_re.search(CXX_version)
 508     if (clang_version_match):
 509         clang_version = clang_version_match.groups()[0]
 510         if compareVersions(clang_version, "3.1") < 0:
 511             print('Error: clang version 3.1 or newer required.')
 512             print('       Installed version:', clang_version)
 513             Exit(1)
 514     else:
 515         print('Error: Unable to determine clang version.')
 516         Exit(1)
 517
 518     # clang has a few additional warnings that we disable, extraneous
 519     # parantheses are allowed due to Ruby's printing of the AST,
 520     # finally self assignments are allowed as the generated CPU code
 521     # is relying on this
 522     main.Append(CCFLAGS=['-Wno-parentheses',
 523                          '-Wno-self-assign',
 524                          # Some versions of libstdc++ (4.8?) seem to
 525                          # use struct hash and class hash
 526                          # interchangeably.
 527                          '-Wno-mismatched-tags',
 528                          ])
 529
 530     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
 531
 532     # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
 533     # opposed to libstdc++, as the later is dated.
 534     if sys.platform == "darwin":
 535         main.Append(CXXFLAGS=['-stdlib=libc++'])
 536         main.Append(LIBS=['c++'])
 537
 538     # On FreeBSD we need libthr.
 539     if sys.platform.startswith('freebsd'):
 540         main.Append(LIBS=['thr'])
 541
 542     # We require clang >= 3.1, so there is no need to check any
 543     # versions here.
 544     if GetOption('with_ubsan'):
 545         if GetOption('with_asan'):
 546             main.Append(CCFLAGS=['-fsanitize=address,undefined',
 547                                  '-fno-omit-frame-pointer'],
 548                        LINKFLAGS='-fsanitize=address,undefined')
 549         else:
 550             main.Append(CCFLAGS='-fsanitize=undefined',
 551                         LINKFLAGS='-fsanitize=undefined')
 552
 553     elif GetOption('with_asan'):
 554         main.Append(CCFLAGS=['-fsanitize=address',
 555                              '-fno-omit-frame-pointer'],
 556                    LINKFLAGS='-fsanitize=address')
 557
 558 else:
 559     print(termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal, end=' ')
 560     print("Don't know what compiler options to use for your compiler.")
 561     print(termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX'])
 562     print(termcap.Yellow + '       version:' + termcap.Normal, end=' ')
 563     if not CXX_version:
 564         print(termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +
 565               termcap.Normal)
 566     else:
 567         print(CXX_version.replace('\n', '<nl>'))
 568     print("       If you're trying to use a compiler other than GCC")
 569     print("       or clang, there appears to be something wrong with your")
 570     print("       environment.")
 571     print("       ")
 572     print("       If you are trying to use a compiler other than those listed")
 573     print("       above you will need to ease fix SConstruct and ")
 574     print("       src/SConscript to support that compiler.")
 575     Exit(1)
 576
 577 # Set up common yacc/bison flags (needed for Ruby)
 578 main['YACCFLAGS'] = '-d'
 579 main['YACCHXXFILESUFFIX'] = '.hh'
 580
 581 # Do this after we save setting back, or else we'll tack on an
 582 # extra 'qdo' every time we run scons.
 583 if main['BATCH']:
 584     main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
 585     main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
 586     main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
 587     main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
 588     main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
 589
 590 if sys.platform == 'cygwin':
 591     # cygwin has some header file issues...
 592     main.Append(CCFLAGS=["-Wno-uninitialized"])
 593
 594
 595 have_pkg_config = readCommand(['pkg-config', '--version'], exception='')
 596
 597 # Check for the protobuf compiler
 598 protoc_version = readCommand([main['PROTOC'], '--version'],
 599                              exception='').split()
 600
 601 # First two words should be "libprotoc x.y.z"
 602 if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
 603     print(termcap.Yellow + termcap.Bold +
 604         'Warning: Protocol buffer compiler (protoc) not found.\n' +
 605         '         Please install protobuf-compiler for tracing support.' +
 606         termcap.Normal)
 607     main['PROTOC'] = False
 608 else:
 609     # Based on the availability of the compress stream wrappers,
 610     # require 2.1.0
 611     min_protoc_version = '2.1.0'
 612     if compareVersions(protoc_version[1], min_protoc_version) < 0:
 613         print(termcap.Yellow + termcap.Bold +
 614             'Warning: protoc version', min_protoc_version,
 615             'or newer required.\n' +
 616             '         Installed version:', protoc_version[1],
 617             termcap.Normal)
 618         main['PROTOC'] = False
 619     else:
 620         # Attempt to determine the appropriate include path and
 621         # library path using pkg-config, that means we also need to
 622         # check for pkg-config. Note that it is possible to use
 623         # protobuf without the involvement of pkg-config. Later on we
 624         # check go a library config check and at that point the test
 625         # will fail if libprotobuf cannot be found.
 626         if have_pkg_config:
 627             try:
 628                 # Attempt to establish what linking flags to add for protobuf
 629                 # using pkg-config
 630                 main.ParseConfig('pkg-config --cflags --libs-only-L protobuf')
 631             except:
 632                 print(termcap.Yellow + termcap.Bold +
 633                     'Warning: pkg-config could not get protobuf flags.' +
 634                     termcap.Normal)
 635
 636
 637 # Check for 'timeout' from GNU coreutils. If present, regressions will
 638 # be run with a time limit. We require version 8.13 since we rely on
 639 # support for the '--foreground' option.
 640 if sys.platform.startswith('freebsd'):
 641     timeout_lines = readCommand(['gtimeout', '--version'],
 642                                 exception='').splitlines()
 643 else:
 644     timeout_lines = readCommand(['timeout', '--version'],
 645                                 exception='').splitlines()
 646 # Get the first line and tokenize it
 647 timeout_version = timeout_lines[0].split() if timeout_lines else []
 648 main['TIMEOUT'] =  timeout_version and \
 649     compareVersions(timeout_version[-1], '8.13') >= 0
 650
 651 # Add a custom Check function to test for structure members.
 652 def CheckMember(context, include, decl, member, include_quotes="<>"):
 653     context.Message("Checking for member %s in %s..." %
 654                     (member, decl))
 655     text = """
 656 #include %(header)s
 657 int main(){
 658   %(decl)s test;
 659   (void)test.%(member)s;
 660   return 0;
 661 };
 662 """ % { "header" : include_quotes[0] + include + include_quotes[1],
 663         "decl" : decl,
 664         "member" : member,
 665         }
 666
 667     ret = context.TryCompile(text, extension=".cc")
 668     context.Result(ret)
 669     return ret
 670
 671 # Platform-specific configuration.  Note again that we assume that all
 672 # builds under a given build root run on the same host platform.
 673 conf = Configure(main,
 674                  conf_dir = joinpath(build_root, '.scons_config'),
 675                  log_file = joinpath(build_root, 'scons_config.log'),
 676                  custom_tests = {
 677         'CheckMember' : CheckMember,
 678         })
 679
 680 # Check if we should compile a 64 bit binary on Mac OS X/Darwin
 681 try:
 682     import platform
 683     uname = platform.uname()
 684     if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
 685         if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
 686             main.Append(CCFLAGS=['-arch', 'x86_64'])
 687             main.Append(CFLAGS=['-arch', 'x86_64'])
 688             main.Append(LINKFLAGS=['-arch', 'x86_64'])
 689             main.Append(ASFLAGS=['-arch', 'x86_64'])
 690 except:
 691     pass
 692
 693 # Recent versions of scons substitute a "Null" object for Configure()
 694 # when configuration isn't necessary, e.g., if the "--help" option is
 695 # present.  Unfortuantely this Null object always returns false,
 696 # breaking all our configuration checks.  We replace it with our own
 697 # more optimistic null object that returns True instead.
 698 if not conf:
 699     def NullCheck(*args, **kwargs):
 700         return True
 701
 702     class NullConf:
 703         def __init__(self, env):
 704             self.env = env
 705         def Finish(self):
 706             return self.env
 707         def __getattr__(self, mname):
 708             return NullCheck
 709
 710     conf = NullConf(main)
 711
 712 # Cache build files in the supplied directory.
 713 if main['M5_BUILD_CACHE']:
 714     print('Using build cache located at', main['M5_BUILD_CACHE'])
 715     CacheDir(main['M5_BUILD_CACHE'])
 716
 717 main['USE_PYTHON'] = not GetOption('without_python')
 718 if main['USE_PYTHON']:
 719     # Find Python include and library directories for embedding the
 720     # interpreter. We rely on python-config to resolve the appropriate
 721     # includes and linker flags. ParseConfig does not seem to understand
 722     # the more exotic linker flags such as -Xlinker and -export-dynamic so
 723     # we add them explicitly below. If you want to link in an alternate
 724     # version of python, see above for instructions on how to invoke
 725     # scons with the appropriate PATH set.
 726
 727     python_config = find_first_prog(main['PYTHON_CONFIG'])
 728     if python_config is None:
 729         print("Error: can't find a suitable python-config, tried %s" % \
 730               main['PYTHON_CONFIG'])
 731         Exit(1)
 732
 733     print("Info: Using Python config: %s" % (python_config, ))
 734     py_includes = readCommand([python_config, '--includes'],
 735                               exception='').split()
 736     py_includes = filter(lambda s: match(r'.*\/include\/.*',s), py_includes)
 737     # Strip the -I from the include folders before adding them to the
 738     # CPPPATH
 739     py_includes = map(lambda s: s[2:] if s.startswith('-I') else s, py_includes)
 740     main.Append(CPPPATH=py_includes)
 741
 742     # Read the linker flags and split them into libraries and other link
 743     # flags. The libraries are added later through the call the CheckLib.
 744     py_ld_flags = readCommand([python_config, '--ldflags'],
 745         exception='').split()
 746     py_libs = []
 747     for lib in py_ld_flags:
 748          if not lib.startswith('-l'):
 749              main.Append(LINKFLAGS=[lib])
 750          else:
 751              lib = lib[2:]
 752              if lib not in py_libs:
 753                  py_libs.append(lib)
 754
 755     # verify that this stuff works
 756     if not conf.CheckHeader('Python.h', '<>'):
 757         print("Error: Check failed for Python.h header in", py_includes)
 758         print("Two possible reasons:")
 759         print("1. Python headers are not installed (You can install the "
 760               "package python-dev on Ubuntu and RedHat)")
 761         print("2. SCons is using a wrong C compiler. This can happen if "
 762               "CC has the wrong value.")
 763         print("CC = %s" % main['CC'])
 764         Exit(1)
 765
 766     for lib in py_libs:
 767         if not conf.CheckLib(lib):
 768             print("Error: can't find library %s required by python" % lib)
 769             Exit(1)
 770
 771 # On Solaris you need to use libsocket for socket ops
 772 if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
 773    if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
 774        print("Can't find library with socket calls (e.g. accept())")
 775        Exit(1)
 776
 777 # Check for zlib.  If the check passes, libz will be automatically
 778 # added to the LIBS environment variable.
 779 if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
 780     print('Error: did not find needed zlib compression library '
 781           'and/or zlib.h header file.')
 782     print('       Please install zlib and try again.')
 783     Exit(1)
 784
 785 # If we have the protobuf compiler, also make sure we have the
 786 # development libraries. If the check passes, libprotobuf will be
 787 # automatically added to the LIBS environment variable. After
 788 # this, we can use the HAVE_PROTOBUF flag to determine if we have
 789 # got both protoc and libprotobuf available.
 790 main['HAVE_PROTOBUF'] = main['PROTOC'] and \
 791     conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
 792                             'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
 793
 794 # Valgrind gets much less confused if you tell it when you're using
 795 # alternative stacks.
 796 main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
 797
 798 # If we have the compiler but not the library, print another warning.
 799 if main['PROTOC'] and not main['HAVE_PROTOBUF']:
 800     print(termcap.Yellow + termcap.Bold +
 801         'Warning: did not find protocol buffer library and/or headers.\n' +
 802     '       Please install libprotobuf-dev for tracing support.' +
 803     termcap.Normal)
 804
 805 # Check for librt.
 806 have_posix_clock = \
 807     conf.CheckLibWithHeader(None, 'time.h', 'C',
 808                             'clock_nanosleep(0,0,NULL,NULL);') or \
 809     conf.CheckLibWithHeader('rt', 'time.h', 'C',
 810                             'clock_nanosleep(0,0,NULL,NULL);')
 811
 812 have_posix_timers = \
 813     conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
 814                             'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
 815
 816 if not GetOption('without_tcmalloc'):
 817     if conf.CheckLib('tcmalloc'):
 818         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 819     elif conf.CheckLib('tcmalloc_minimal'):
 820         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 821     else:
 822         print(termcap.Yellow + termcap.Bold +
 823               "You can get a 12% performance improvement by "
 824               "installing tcmalloc (libgoogle-perftools-dev package "
 825               "on Ubuntu or RedHat)." + termcap.Normal)
 826
 827
 828 # Detect back trace implementations. The last implementation in the
 829 # list will be used by default.
 830 backtrace_impls = [ "none" ]
 831
 832 backtrace_checker = 'char temp;' + \
 833     ' backtrace_symbols_fd((void*)&temp, 0, 0);'
 834 if conf.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker):
 835     backtrace_impls.append("glibc")
 836 elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
 837                              backtrace_checker):
 838     # NetBSD and FreeBSD need libexecinfo.
 839     backtrace_impls.append("glibc")
 840     main.Append(LIBS=['execinfo'])
 841
 842 if backtrace_impls[-1] == "none":
 843     default_backtrace_impl = "none"
 844     print(termcap.Yellow + termcap.Bold +
 845         "No suitable back trace implementation found." +
 846         termcap.Normal)
 847
 848 if not have_posix_clock:
 849     print("Can't find library for POSIX clocks.")
 850
 851 # Check for <fenv.h> (C99 FP environment control)
 852 have_fenv = conf.CheckHeader('fenv.h', '<>')
 853 if not have_fenv:
 854     print("Warning: Header file <fenv.h> not found.")
 855     print("         This host has no IEEE FP rounding mode control.")
 856
 857 # Check for <png.h> (libpng library needed if wanting to dump
 858 # frame buffer image in png format)
 859 have_png = conf.CheckHeader('png.h', '<>')
 860 if not have_png:
 861     print("Warning: Header file <png.h> not found.")
 862     print("         This host has no libpng library.")
 863     print("         Disabling support for PNG framebuffers.")
 864
 865 # Check if we should enable KVM-based hardware virtualization. The API
 866 # we rely on exists since version 2.6.36 of the kernel, but somehow
 867 # the KVM_API_VERSION does not reflect the change. We test for one of
 868 # the types as a fall back.
 869 have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
 870 if not have_kvm:
 871     print("Info: Compatible header file <linux/kvm.h> not found, "
 872           "disabling KVM support.")
 873
 874 # Check if the TUN/TAP driver is available.
 875 have_tuntap = conf.CheckHeader('linux/if_tun.h', '<>')
 876 if not have_tuntap:
 877     print("Info: Compatible header file <linux/if_tun.h> not found.")
 878
 879 # x86 needs support for xsave. We test for the structure here since we
 880 # won't be able to run new tests by the time we know which ISA we're
 881 # targeting.
 882 have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
 883                                     '#include <linux/kvm.h>') != 0
 884
 885 # Check if the requested target ISA is compatible with the host
 886 def is_isa_kvm_compatible(isa):
 887     try:
 888         import platform
 889         host_isa = platform.machine()
 890     except:
 891         print("Warning: Failed to determine host ISA.")
 892         return False
 893
 894     if not have_posix_timers:
 895         print("Warning: Can not enable KVM, host seems to lack support "
 896               "for POSIX timers")
 897         return False
 898
 899     if isa == "arm":
 900         return host_isa in ( "armv7l", "aarch64" )
 901     elif isa == "x86":
 902         if host_isa != "x86_64":
 903             return False
 904
 905         if not have_kvm_xsave:
 906             print("KVM on x86 requires xsave support in kernel headers.")
 907             return False
 908
 909         return True
 910     else:
 911         return False
 912
 913
 914 # Check if the exclude_host attribute is available. We want this to
 915 # get accurate instruction counts in KVM.
 916 main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
 917     'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
 918
 919 def check_hdf5():
 920     return \
 921         conf.CheckLibWithHeader('hdf5', 'hdf5.h', 'C',
 922                                 'H5Fcreate("", 0, 0, 0);') and \
 923         conf.CheckLibWithHeader('hdf5_cpp', 'H5Cpp.h', 'C++',
 924                                 'H5::H5File("", 0);')
 925
 926 def check_hdf5_pkg(name):
 927     print("Checking for %s using pkg-config..." % name, end="")
 928     if not have_pkg_config:
 929         print(" pkg-config not found")
 930         return False
 931
 932     try:
 933         main.ParseConfig('pkg-config --cflags-only-I --libs-only-L %s' % name)
 934         print(" yes")
 935         return True
 936     except:
 937         print(" no")
 938         return False
 939
 940 # Check if there is a pkg-config configuration for hdf5. If we find
 941 # it, setup the environment to enable linking and header inclusion. We
 942 # don't actually try to include any headers or link with hdf5 at this
 943 # stage.
 944 if not check_hdf5_pkg('hdf5-serial'):
 945     check_hdf5_pkg('hdf5')
 946
 947 # Check if the HDF5 libraries can be found. This check respects the
 948 # include path and library path provided by pkg-config. We perform
 949 # this check even if there isn't a pkg-config configuration for hdf5
 950 # since some installations don't use pkg-config.
 951 have_hdf5 = check_hdf5()
 952 if not have_hdf5:
 953     print("Warning: Couldn't find any HDF5 C++ libraries. Disabling")
 954     print("         HDF5 support.")
 955
 956 ######################################################################
 957 #
 958 # Finish the configuration
 959 #
 960 main = conf.Finish()
 961
 962 ######################################################################
 963 #
 964 # Collect all non-global variables
 965 #
 966
 967 # Define the universe of supported ISAs
 968 all_isa_list = [ ]
 969 all_gpu_isa_list = [ ]
 970 Export('all_isa_list')
 971 Export('all_gpu_isa_list')
 972
 973 class CpuModel(object):
 974     '''The CpuModel class encapsulates everything the ISA parser needs to
 975     know about a particular CPU model.'''
 976
 977     # Dict of available CPU model objects.  Accessible as CpuModel.dict.
 978     dict = {}
 979
 980     # Constructor.  Automatically adds models to CpuModel.dict.
 981     def __init__(self, name, default=False):
 982         self.name = name           # name of model
 983
 984         # This cpu is enabled by default
 985         self.default = default
 986
 987         # Add self to dict
 988         if name in CpuModel.dict:
 989             raise AttributeError, "CpuModel '%s' already registered" % name
 990         CpuModel.dict[name] = self
 991
 992 Export('CpuModel')
 993
 994 # Sticky variables get saved in the variables file so they persist from
 995 # one invocation to the next (unless overridden, in which case the new
 996 # value becomes sticky).
 997 sticky_vars = Variables(args=ARGUMENTS)
 998 Export('sticky_vars')
 999
1000 # Sticky variables that should be exported
1001 export_vars = []
1002 Export('export_vars')
1003
1004 # For Ruby
1005 all_protocols = []
1006 Export('all_protocols')
1007 protocol_dirs = []
1008 Export('protocol_dirs')
1009 slicc_includes = []
1010 Export('slicc_includes')
1011
1012 # Walk the tree and execute all SConsopts scripts that wil add to the
1013 # above variables
1014 if GetOption('verbose'):
1015     print("Reading SConsopts")
1016 for bdir in [ base_dir ] + extras_dir_list:
1017     if not isdir(bdir):
1018         print("Error: directory '%s' does not exist" % bdir)
1019         Exit(1)
1020     for root, dirs, files in os.walk(bdir):
1021         if 'SConsopts' in files:
1022             if GetOption('verbose'):
1023                 print("Reading", joinpath(root, 'SConsopts'))
1024             SConscript(joinpath(root, 'SConsopts'))
1025
1026 all_isa_list.sort()
1027 all_gpu_isa_list.sort()
1028
1029 sticky_vars.AddVariables(
1030     EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
1031     EnumVariable('TARGET_GPU_ISA', 'Target GPU ISA', 'hsail', all_gpu_isa_list),
1032     ListVariable('CPU_MODELS', 'CPU models',
1033                  sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
1034                  sorted(CpuModel.dict.keys())),
1035     BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
1036                  False),
1037     BoolVariable('SS_COMPATIBLE_FP',
1038                  'Make floating-point results compatible with SimpleScalar',
1039                  False),
1040     BoolVariable('USE_SSE2',
1041                  'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
1042                  False),
1043     BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
1044     BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
1045     BoolVariable('USE_PNG',  'Enable support for PNG images', have_png),
1046     BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability',
1047                  False),
1048     BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models',
1049                  have_kvm),
1050     BoolVariable('USE_TUNTAP',
1051                  'Enable using a tap device to bridge to the host network',
1052                  have_tuntap),
1053     BoolVariable('BUILD_GPU', 'Build the compute-GPU model', False),
1054     EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1055                   all_protocols),
1056     EnumVariable('BACKTRACE_IMPL', 'Post-mortem dump implementation',
1057                  backtrace_impls[-1], backtrace_impls),
1058     ('NUMBER_BITS_PER_SET', 'Max elements in set (default 64)',
1059                  64),
1060     BoolVariable('USE_HDF5', 'Enable the HDF5 support', have_hdf5),
1061     )
1062
1063 # These variables get exported to #defines in config/*.hh (see src/SConscript).
1064 export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'TARGET_GPU_ISA',
1065                 'CP_ANNOTATE', 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP',
1066                 'PROTOCOL', 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
1067                 'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG',
1068                 'NUMBER_BITS_PER_SET', 'USE_HDF5']
1069
1070 ###################################################
1071 #
1072 # Define a SCons builder for configuration flag headers.
1073 #
1074 ###################################################
1075
1076 # This function generates a config header file that #defines the
1077 # variable symbol to the current variable setting (0 or 1).  The source
1078 # operands are the name of the variable and a Value node containing the
1079 # value of the variable.
1080 def build_config_file(target, source, env):
1081     (variable, value) = [s.get_contents() for s in source]
1082     f = file(str(target[0]), 'w')
1083     print('#define', variable, value, file=f)
1084     f.close()
1085     return None
1086
1087 # Combine the two functions into a scons Action object.
1088 config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1089
1090 # The emitter munges the source & target node lists to reflect what
1091 # we're really doing.
1092 def config_emitter(target, source, env):
1093     # extract variable name from Builder arg
1094     variable = str(target[0])
1095     # True target is config header file
1096     target = joinpath('config', variable.lower() + '.hh')
1097     val = env[variable]
1098     if isinstance(val, bool):
1099         # Force value to 0/1
1100         val = int(val)
1101     elif isinstance(val, str):
1102         val = '"' + val + '"'
1103
1104     # Sources are variable name & value (packaged in SCons Value nodes)
1105     return ([target], [Value(variable), Value(val)])
1106
1107 config_builder = Builder(emitter = config_emitter, action = config_action)
1108
1109 main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1110
1111 ###################################################
1112 #
1113 # Builders for static and shared partially linked object files.
1114 #
1115 ###################################################
1116
1117 partial_static_builder = Builder(action=SCons.Defaults.LinkAction,
1118                                  src_suffix='$OBJSUFFIX',
1119                                  src_builder=['StaticObject', 'Object'],
1120                                  LINKFLAGS='$PLINKFLAGS',
1121                                  LIBS='')
1122
1123 def partial_shared_emitter(target, source, env):
1124     for tgt in target:
1125         tgt.attributes.shared = 1
1126     return (target, source)
1127 partial_shared_builder = Builder(action=SCons.Defaults.ShLinkAction,
1128                                  emitter=partial_shared_emitter,
1129                                  src_suffix='$SHOBJSUFFIX',
1130                                  src_builder='SharedObject',
1131                                  SHLINKFLAGS='$PSHLINKFLAGS',
1132                                  LIBS='')
1133
1134 main.Append(BUILDERS = { 'PartialShared' : partial_shared_builder,
1135                          'PartialStatic' : partial_static_builder })
1136
1137 def add_local_rpath(env, *targets):
1138     '''Set up an RPATH for a library which lives in the build directory.
1139
1140     The construction environment variable BIN_RPATH_PREFIX should be set to
1141     the relative path of the build directory starting from the location of the
1142     binary.'''
1143     for target in targets:
1144         target = env.Entry(target)
1145         if not isinstance(target, SCons.Node.FS.Dir):
1146             target = target.dir
1147         relpath = os.path.relpath(target.abspath, env['BUILDDIR'])
1148         components = [
1149             '\\$$ORIGIN',
1150             '${BIN_RPATH_PREFIX}',
1151             relpath
1152         ]
1153         env.Append(RPATH=[env.Literal(os.path.join(*components))])
1154
1155 if sys.platform != "darwin":
1156     main.Append(LINKFLAGS=Split('-z origin'))
1157
1158 main.AddMethod(add_local_rpath, 'AddLocalRPATH')
1159
1160 # builds in ext are shared across all configs in the build root.
1161 ext_dir = abspath(joinpath(str(main.root), 'ext'))
1162 ext_build_dirs = []
1163 for root, dirs, files in os.walk(ext_dir):
1164     if 'SConscript' in files:
1165         build_dir = os.path.relpath(root, ext_dir)
1166         ext_build_dirs.append(build_dir)
1167         main.SConscript(joinpath(root, 'SConscript'),
1168                         variant_dir=joinpath(build_root, build_dir))
1169
1170 gdb_xml_dir = joinpath(ext_dir, 'gdb-xml')
1171 Export('gdb_xml_dir')
1172
1173 main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
1174
1175 ###################################################
1176 #
1177 # This builder and wrapper method are used to set up a directory with
1178 # switching headers. Those are headers which are in a generic location and
1179 # that include more specific headers from a directory chosen at build time
1180 # based on the current build settings.
1181 #
1182 ###################################################
1183
1184 def build_switching_header(target, source, env):
1185     path = str(target[0])
1186     subdir = str(source[0])
1187     dp, fp = os.path.split(path)
1188     dp = os.path.relpath(os.path.realpath(dp),
1189                          os.path.realpath(env['BUILDDIR']))
1190     with open(path, 'w') as hdr:
1191         print('#include "%s/%s/%s"' % (dp, subdir, fp), file=hdr)
1192
1193 switching_header_action = MakeAction(build_switching_header,
1194                                      Transform('GENERATE'))
1195
1196 switching_header_builder = Builder(action=switching_header_action,
1197                                    source_factory=Value,
1198                                    single_source=True)
1199
1200 main.Append(BUILDERS = { 'SwitchingHeader': switching_header_builder })
1201
1202 def switching_headers(self, headers, source):
1203     for header in headers:
1204         self.SwitchingHeader(header, source)
1205
1206 main.AddMethod(switching_headers, 'SwitchingHeaders')
1207
1208 ###################################################
1209 #
1210 # Define build environments for selected configurations.
1211 #
1212 ###################################################
1213
1214 for variant_path in variant_paths:
1215     if not GetOption('silent'):
1216         print("Building in", variant_path)
1217
1218     # Make a copy of the build-root environment to use for this config.
1219     env = main.Clone()
1220     env['BUILDDIR'] = variant_path
1221
1222     # variant_dir is the tail component of build path, and is used to
1223     # determine the build parameters (e.g., 'ALPHA_SE')
1224     (build_root, variant_dir) = splitpath(variant_path)
1225
1226     # Set env variables according to the build directory config.
1227     sticky_vars.files = []
1228     # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1229     # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1230     # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1231     current_vars_file = joinpath(build_root, 'variables', variant_dir)
1232     if isfile(current_vars_file):
1233         sticky_vars.files.append(current_vars_file)
1234         if not GetOption('silent'):
1235             print("Using saved variables file %s" % current_vars_file)
1236     elif variant_dir in ext_build_dirs:
1237         # Things in ext are built without a variant directory.
1238         continue
1239     else:
1240         # Build dir-specific variables file doesn't exist.
1241
1242         # Make sure the directory is there so we can create it later
1243         opt_dir = dirname(current_vars_file)
1244         if not isdir(opt_dir):
1245             mkdir(opt_dir)
1246
1247         # Get default build variables from source tree.  Variables are
1248         # normally determined by name of $VARIANT_DIR, but can be
1249         # overridden by '--default=' arg on command line.
1250         default = GetOption('default')
1251         opts_dir = joinpath(main.root.abspath, 'build_opts')
1252         if default:
1253             default_vars_files = [joinpath(build_root, 'variables', default),
1254                                   joinpath(opts_dir, default)]
1255         else:
1256             default_vars_files = [joinpath(opts_dir, variant_dir)]
1257         existing_files = filter(isfile, default_vars_files)
1258         if existing_files:
1259             default_vars_file = existing_files[0]
1260             sticky_vars.files.append(default_vars_file)
1261             print("Variables file %s not found,\n  using defaults in %s"
1262                   % (current_vars_file, default_vars_file))
1263         else:
1264             print("Error: cannot find variables file %s or "
1265                   "default file(s) %s"
1266                   % (current_vars_file, ' or '.join(default_vars_files)))
1267             Exit(1)
1268
1269     # Apply current variable settings to env
1270     sticky_vars.Update(env)
1271
1272     help_texts["local_vars"] += \
1273         "Build variables for %s:\n" % variant_dir \
1274                  + sticky_vars.GenerateHelpText(env)
1275
1276     # Process variable settings.
1277
1278     if not have_fenv and env['USE_FENV']:
1279         print("Warning: <fenv.h> not available; "
1280               "forcing USE_FENV to False in", variant_dir + ".")
1281         env['USE_FENV'] = False
1282
1283     if not env['USE_FENV']:
1284         print("Warning: No IEEE FP rounding mode control in",
1285               variant_dir + ".")
1286         print("         FP results may deviate slightly from other platforms.")
1287
1288     if not have_png and env['USE_PNG']:
1289         print("Warning: <png.h> not available; "
1290               "forcing USE_PNG to False in", variant_dir + ".")
1291         env['USE_PNG'] = False
1292
1293     if env['USE_PNG']:
1294         env.Append(LIBS=['png'])
1295
1296     if env['EFENCE']:
1297         env.Append(LIBS=['efence'])
1298
1299     if env['USE_KVM']:
1300         if not have_kvm:
1301             print("Warning: Can not enable KVM, host seems to "
1302                   "lack KVM support")
1303             env['USE_KVM'] = False
1304         elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1305             print("Info: KVM support disabled due to unsupported host and "
1306                   "target ISA combination")
1307             env['USE_KVM'] = False
1308
1309     if env['USE_TUNTAP']:
1310         if not have_tuntap:
1311             print("Warning: Can't connect EtherTap with a tap device.")
1312             env['USE_TUNTAP'] = False
1313
1314     if env['BUILD_GPU']:
1315         env.Append(CPPDEFINES=['BUILD_GPU'])
1316
1317     # Warn about missing optional functionality
1318     if env['USE_KVM']:
1319         if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1320             print("Warning: perf_event headers lack support for the "
1321                   "exclude_host attribute. KVM instruction counts will "
1322                   "be inaccurate.")
1323
1324     # Save sticky variable settings back to current variables file
1325     sticky_vars.Save(current_vars_file, env)
1326
1327     if env['USE_SSE2']:
1328         env.Append(CCFLAGS=['-msse2'])
1329
1330     env.Append(CCFLAGS='$CCFLAGS_EXTRA')
1331     env.Append(LINKFLAGS='$LDFLAGS_EXTRA')
1332
1333     # The src/SConscript file sets up the build rules in 'env' according
1334     # to the configured variables.  It returns a list of environments,
1335     # one for each variant build (debug, opt, etc.)
1336     SConscript('src/SConscript', variant_dir = variant_path, exports = 'env')
1337
1338 # base help text
1339 Help('''
1340 Usage: scons [scons options] [build variables] [target(s)]
1341
1342 Extra scons options:
1343 %(options)s
1344
1345 Global build variables:
1346 %(global_vars)s
1347
1348 %(local_vars)s
1349 ''' % help_texts)