SConstruct

   1 # -*- mode:python -*-
   2
   3 # Copyright (c) 2013, 2015-2017 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
 101 from m5.util import compareVersions, readCommand
 102
 103 help_texts = {
 104     "options" : "",
 105     "global_vars" : "",
 106     "local_vars" : ""
 107 }
 108
 109 Export("help_texts")
 110
 111
 112 # There's a bug in scons in that (1) by default, the help texts from
 113 # AddOption() are supposed to be displayed when you type 'scons -h'
 114 # and (2) you can override the help displayed by 'scons -h' using the
 115 # Help() function, but these two features are incompatible: once
 116 # you've overridden the help text using Help(), there's no way to get
 117 # at the help texts from AddOptions.  See:
 118 #     http://scons.tigris.org/issues/show_bug.cgi?id=2356
 119 #     http://scons.tigris.org/issues/show_bug.cgi?id=2611
 120 # This hack lets us extract the help text from AddOptions and
 121 # re-inject it via Help().  Ideally someday this bug will be fixed and
 122 # we can just use AddOption directly.
 123 def AddLocalOption(*args, **kwargs):
 124     col_width = 30
 125
 126     help = "  " + ", ".join(args)
 127     if "help" in kwargs:
 128         length = len(help)
 129         if length >= col_width:
 130             help += "\n" + " " * col_width
 131         else:
 132             help += " " * (col_width - length)
 133         help += kwargs["help"]
 134     help_texts["options"] += help + "\n"
 135
 136     AddOption(*args, **kwargs)
 137
 138 AddLocalOption('--colors', dest='use_colors', action='store_true',
 139                help="Add color to abbreviated scons output")
 140 AddLocalOption('--no-colors', dest='use_colors', action='store_false',
 141                help="Don't add color to abbreviated scons output")
 142 AddLocalOption('--with-cxx-config', dest='with_cxx_config',
 143                action='store_true',
 144                help="Build with support for C++-based configuration")
 145 AddLocalOption('--default', dest='default', type='string', action='store',
 146                help='Override which build_opts file to use for defaults')
 147 AddLocalOption('--ignore-style', dest='ignore_style', action='store_true',
 148                help='Disable style checking hooks')
 149 AddLocalOption('--gold-linker', dest='gold_linker', action='store_true',
 150                help='Use the gold linker')
 151 AddLocalOption('--no-lto', dest='no_lto', action='store_true',
 152                help='Disable Link-Time Optimization for fast')
 153 AddLocalOption('--force-lto', dest='force_lto', action='store_true',
 154                help='Use Link-Time Optimization instead of partial linking' +
 155                     ' when the compiler doesn\'t support using them together.')
 156 AddLocalOption('--update-ref', dest='update_ref', action='store_true',
 157                help='Update test reference outputs')
 158 AddLocalOption('--verbose', dest='verbose', action='store_true',
 159                help='Print full tool command lines')
 160 AddLocalOption('--without-python', dest='without_python',
 161                action='store_true',
 162                help='Build without Python configuration support')
 163 AddLocalOption('--without-tcmalloc', dest='without_tcmalloc',
 164                action='store_true',
 165                help='Disable linking against tcmalloc')
 166 AddLocalOption('--with-ubsan', dest='with_ubsan', action='store_true',
 167                help='Build with Undefined Behavior Sanitizer if available')
 168 AddLocalOption('--with-asan', dest='with_asan', action='store_true',
 169                help='Build with Address Sanitizer if available')
 170
 171 if GetOption('no_lto') and GetOption('force_lto'):
 172     print('--no-lto and --force-lto are mutually exclusive')
 173     Exit(1)
 174
 175 ########################################################################
 176 #
 177 # Set up the main build environment.
 178 #
 179 ########################################################################
 180
 181 main = Environment()
 182
 183 from gem5_scons import Transform
 184 from gem5_scons.util import get_termcap
 185 termcap = get_termcap()
 186
 187 main_dict_keys = main.Dictionary().keys()
 188
 189 # Check that we have a C/C++ compiler
 190 if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
 191     print("No C++ compiler installed (package g++ on Ubuntu and RedHat)")
 192     Exit(1)
 193
 194 ###################################################
 195 #
 196 # Figure out which configurations to set up based on the path(s) of
 197 # the target(s).
 198 #
 199 ###################################################
 200
 201 # Find default configuration & binary.
 202 Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))
 203
 204 # helper function: find last occurrence of element in list
 205 def rfind(l, elt, offs = -1):
 206     for i in range(len(l)+offs, 0, -1):
 207         if l[i] == elt:
 208             return i
 209     raise ValueError, "element not found"
 210
 211 # Take a list of paths (or SCons Nodes) and return a list with all
 212 # paths made absolute and ~-expanded.  Paths will be interpreted
 213 # relative to the launch directory unless a different root is provided
 214 def makePathListAbsolute(path_list, root=GetLaunchDir()):
 215     return [abspath(joinpath(root, expanduser(str(p))))
 216             for p in path_list]
 217
 218 def find_first_prog(prog_names):
 219     """Find the absolute path to the first existing binary in prog_names"""
 220
 221     if not isinstance(prog_names, (list, tuple)):
 222         prog_names = [ prog_names ]
 223
 224     for p in prog_names:
 225         p = main.WhereIs(p)
 226         if p is not None:
 227             return p
 228
 229     return None
 230
 231 # Each target must have 'build' in the interior of the path; the
 232 # directory below this will determine the build parameters.  For
 233 # example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
 234 # recognize that ALPHA_SE specifies the configuration because it
 235 # follow 'build' in the build path.
 236
 237 # The funky assignment to "[:]" is needed to replace the list contents
 238 # in place rather than reassign the symbol to a new list, which
 239 # doesn't work (obviously!).
 240 BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
 241
 242 # Generate a list of the unique build roots and configs that the
 243 # collected targets reference.
 244 variant_paths = []
 245 build_root = None
 246 for t in BUILD_TARGETS:
 247     path_dirs = t.split('/')
 248     try:
 249         build_top = rfind(path_dirs, 'build', -2)
 250     except:
 251         print("Error: no non-leaf 'build' dir found on target path", t)
 252         Exit(1)
 253     this_build_root = joinpath('/',*path_dirs[:build_top+1])
 254     if not build_root:
 255         build_root = this_build_root
 256     else:
 257         if this_build_root != build_root:
 258             print("Error: build targets not under same build root\n"
 259                   "  %s\n  %s" % (build_root, this_build_root))
 260             Exit(1)
 261     variant_path = joinpath('/',*path_dirs[:build_top+2])
 262     if variant_path not in variant_paths:
 263         variant_paths.append(variant_path)
 264
 265 # Make sure build_root exists (might not if this is the first build there)
 266 if not isdir(build_root):
 267     mkdir(build_root)
 268 main['BUILDROOT'] = build_root
 269
 270 Export('main')
 271
 272 main.SConsignFile(joinpath(build_root, "sconsign"))
 273
 274 # Default duplicate option is to use hard links, but this messes up
 275 # when you use emacs to edit a file in the target dir, as emacs moves
 276 # file to file~ then copies to file, breaking the link.  Symbolic
 277 # (soft) links work better.
 278 main.SetOption('duplicate', 'soft-copy')
 279
 280 #
 281 # Set up global sticky variables... these are common to an entire build
 282 # tree (not specific to a particular build like ALPHA_SE)
 283 #
 284
 285 global_vars_file = joinpath(build_root, 'variables.global')
 286
 287 global_vars = Variables(global_vars_file, args=ARGUMENTS)
 288
 289 global_vars.AddVariables(
 290     ('CC', 'C compiler', environ.get('CC', main['CC'])),
 291     ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
 292     ('PYTHON_CONFIG', 'Python config binary to use',
 293      [ 'python2.7-config', 'python-config' ]),
 294     ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
 295     ('BATCH', 'Use batch pool for build and tests', False),
 296     ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
 297     ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
 298     ('EXTRAS', 'Add extra directories to the compilation', '')
 299     )
 300
 301 # Update main environment with values from ARGUMENTS & global_vars_file
 302 global_vars.Update(main)
 303 help_texts["global_vars"] += global_vars.GenerateHelpText(main)
 304
 305 # Save sticky variable settings back to current variables file
 306 global_vars.Save(global_vars_file, main)
 307
 308 # Parse EXTRAS variable to build list of all directories where we're
 309 # look for sources etc.  This list is exported as extras_dir_list.
 310 base_dir = main.srcdir.abspath
 311 if main['EXTRAS']:
 312     extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
 313 else:
 314     extras_dir_list = []
 315
 316 Export('base_dir')
 317 Export('extras_dir_list')
 318
 319 # the ext directory should be on the #includes path
 320 main.Append(CPPPATH=[Dir('ext')])
 321
 322 # Add shared top-level headers
 323 main.Prepend(CPPPATH=Dir('include'))
 324
 325 if GetOption('verbose'):
 326     def MakeAction(action, string, *args, **kwargs):
 327         return Action(action, *args, **kwargs)
 328 else:
 329     MakeAction = Action
 330     main['CCCOMSTR']        = Transform("CC")
 331     main['CXXCOMSTR']       = Transform("CXX")
 332     main['ASCOMSTR']        = Transform("AS")
 333     main['ARCOMSTR']        = Transform("AR", 0)
 334     main['LINKCOMSTR']      = Transform("LINK", 0)
 335     main['SHLINKCOMSTR']    = Transform("SHLINK", 0)
 336     main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
 337     main['M4COMSTR']        = Transform("M4")
 338     main['SHCCCOMSTR']      = Transform("SHCC")
 339     main['SHCXXCOMSTR']     = Transform("SHCXX")
 340 Export('MakeAction')
 341
 342 # Initialize the Link-Time Optimization (LTO) flags
 343 main['LTO_CCFLAGS'] = []
 344 main['LTO_LDFLAGS'] = []
 345
 346 # According to the readme, tcmalloc works best if the compiler doesn't
 347 # assume that we're using the builtin malloc and friends. These flags
 348 # are compiler-specific, so we need to set them after we detect which
 349 # compiler we're using.
 350 main['TCMALLOC_CCFLAGS'] = []
 351
 352 CXX_version = readCommand([main['CXX'],'--version'], exception=False)
 353 CXX_V = readCommand([main['CXX'],'-V'], exception=False)
 354
 355 main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
 356 main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
 357 if main['GCC'] + main['CLANG'] > 1:
 358     print('Error: How can we have two at the same time?')
 359     Exit(1)
 360
 361 # Set up default C++ compiler flags
 362 if main['GCC'] or main['CLANG']:
 363     # As gcc and clang share many flags, do the common parts here
 364     main.Append(CCFLAGS=['-pipe'])
 365     main.Append(CCFLAGS=['-fno-strict-aliasing'])
 366     # Enable -Wall and -Wextra and then disable the few warnings that
 367     # we consistently violate
 368     main.Append(CCFLAGS=['-Wall', '-Wundef', '-Wextra',
 369                          '-Wno-sign-compare', '-Wno-unused-parameter'])
 370     # We always compile using C++11
 371     main.Append(CXXFLAGS=['-std=c++11'])
 372     if sys.platform.startswith('freebsd'):
 373         main.Append(CCFLAGS=['-I/usr/local/include'])
 374         main.Append(CXXFLAGS=['-I/usr/local/include'])
 375
 376     main['FILTER_PSHLINKFLAGS'] = lambda x: str(x).replace(' -shared', '')
 377     main['PSHLINKFLAGS'] = main.subst('${FILTER_PSHLINKFLAGS(SHLINKFLAGS)}')
 378     if GetOption('gold_linker'):
 379         main.Append(LINKFLAGS='-fuse-ld=gold')
 380     main['PLINKFLAGS'] = main.subst('${LINKFLAGS}')
 381     shared_partial_flags = ['-r', '-nostdlib']
 382     main.Append(PSHLINKFLAGS=shared_partial_flags)
 383     main.Append(PLINKFLAGS=shared_partial_flags)
 384
 385     # Treat warnings as errors but white list some warnings that we
 386     # want to allow (e.g., deprecation warnings).
 387     main.Append(CCFLAGS=['-Werror',
 388                          '-Wno-error=deprecated-declarations',
 389                          '-Wno-error=deprecated',
 390                         ])
 391 else:
 392     print(termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal, end=' ')
 393     print("Don't know what compiler options to use for your compiler.")
 394     print(termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX'])
 395     print(termcap.Yellow + '       version:' + termcap.Normal, end = ' ')
 396     if not CXX_version:
 397         print(termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +
 398               termcap.Normal)
 399     else:
 400         print(CXX_version.replace('\n', '<nl>'))
 401     print("       If you're trying to use a compiler other than GCC")
 402     print("       or clang, there appears to be something wrong with your")
 403     print("       environment.")
 404     print("       ")
 405     print("       If you are trying to use a compiler other than those listed")
 406     print("       above you will need to ease fix SConstruct and ")
 407     print("       src/SConscript to support that compiler.")
 408     Exit(1)
 409
 410 if main['GCC']:
 411     # Check for a supported version of gcc. >= 4.8 is chosen for its
 412     # level of c++11 support. See
 413     # http://gcc.gnu.org/projects/cxx0x.html for details.
 414     gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
 415     if compareVersions(gcc_version, "4.8") < 0:
 416         print('Error: gcc version 4.8 or newer required.')
 417         print('       Installed version: ', gcc_version)
 418         Exit(1)
 419
 420     main['GCC_VERSION'] = gcc_version
 421
 422     if compareVersions(gcc_version, '4.9') >= 0:
 423         # Incremental linking with LTO is currently broken in gcc versions
 424         # 4.9 and above. A version where everything works completely hasn't
 425         # yet been identified.
 426         #
 427         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548
 428         main['BROKEN_INCREMENTAL_LTO'] = True
 429     if compareVersions(gcc_version, '6.0') >= 0:
 430         # gcc versions 6.0 and greater accept an -flinker-output flag which
 431         # selects what type of output the linker should generate. This is
 432         # necessary for incremental lto to work, but is also broken in
 433         # current versions of gcc. It may not be necessary in future
 434         # versions. We add it here since it might be, and as a reminder that
 435         # it exists. It's excluded if lto is being forced.
 436         #
 437         # https://gcc.gnu.org/gcc-6/changes.html
 438         # https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03161.html
 439         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69866
 440         if not GetOption('force_lto'):
 441             main.Append(PSHLINKFLAGS='-flinker-output=rel')
 442             main.Append(PLINKFLAGS='-flinker-output=rel')
 443
 444     # Make sure we warn if the user has requested to compile with the
 445     # Undefined Benahvior Sanitizer and this version of gcc does not
 446     # support it.
 447     if GetOption('with_ubsan') and \
 448             compareVersions(gcc_version, '4.9') < 0:
 449         print(termcap.Yellow + termcap.Bold +
 450             'Warning: UBSan is only supported using gcc 4.9 and later.' +
 451             termcap.Normal)
 452
 453     disable_lto = GetOption('no_lto')
 454     if not disable_lto and main.get('BROKEN_INCREMENTAL_LTO', False) and \
 455             not GetOption('force_lto'):
 456         print(termcap.Yellow + termcap.Bold +
 457             'Warning: Your compiler doesn\'t support incremental linking' +
 458             ' and lto at the same time, so lto is being disabled. To force' +
 459             ' lto on anyway, use the --force-lto option. That will disable' +
 460             ' partial linking.' +
 461             termcap.Normal)
 462         disable_lto = True
 463
 464     # Add the appropriate Link-Time Optimization (LTO) flags
 465     # unless LTO is explicitly turned off. Note that these flags
 466     # are only used by the fast target.
 467     if not disable_lto:
 468         # Pass the LTO flag when compiling to produce GIMPLE
 469         # output, we merely create the flags here and only append
 470         # them later
 471         main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 472
 473         # Use the same amount of jobs for LTO as we are running
 474         # scons with
 475         main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
 476
 477     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
 478                                   '-fno-builtin-realloc', '-fno-builtin-free'])
 479
 480     # The address sanitizer is available for gcc >= 4.8
 481     if GetOption('with_asan'):
 482         if GetOption('with_ubsan') and \
 483                 compareVersions(main['GCC_VERSION'], '4.9') >= 0:
 484             main.Append(CCFLAGS=['-fsanitize=address,undefined',
 485                                  '-fno-omit-frame-pointer'],
 486                         LINKFLAGS='-fsanitize=address,undefined')
 487         else:
 488             main.Append(CCFLAGS=['-fsanitize=address',
 489                                  '-fno-omit-frame-pointer'],
 490                         LINKFLAGS='-fsanitize=address')
 491     # Only gcc >= 4.9 supports UBSan, so check both the version
 492     # and the command-line option before adding the compiler and
 493     # linker flags.
 494     elif GetOption('with_ubsan') and \
 495             compareVersions(main['GCC_VERSION'], '4.9') >= 0:
 496         main.Append(CCFLAGS='-fsanitize=undefined')
 497         main.Append(LINKFLAGS='-fsanitize=undefined')
 498
 499 elif main['CLANG']:
 500     # Check for a supported version of clang, >= 3.1 is needed to
 501     # support similar features as gcc 4.8. See
 502     # http://clang.llvm.org/cxx_status.html for details
 503     clang_version_re = re.compile(".* version (\d+\.\d+)")
 504     clang_version_match = clang_version_re.search(CXX_version)
 505     if (clang_version_match):
 506         clang_version = clang_version_match.groups()[0]
 507         if compareVersions(clang_version, "3.1") < 0:
 508             print('Error: clang version 3.1 or newer required.')
 509             print('       Installed version:', clang_version)
 510             Exit(1)
 511     else:
 512         print('Error: Unable to determine clang version.')
 513         Exit(1)
 514
 515     # clang has a few additional warnings that we disable, extraneous
 516     # parantheses are allowed due to Ruby's printing of the AST,
 517     # finally self assignments are allowed as the generated CPU code
 518     # is relying on this
 519     main.Append(CCFLAGS=['-Wno-parentheses',
 520                          '-Wno-self-assign',
 521                          # Some versions of libstdc++ (4.8?) seem to
 522                          # use struct hash and class hash
 523                          # interchangeably.
 524                          '-Wno-mismatched-tags',
 525                          ])
 526
 527     main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
 528
 529     # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
 530     # opposed to libstdc++, as the later is dated.
 531     if sys.platform == "darwin":
 532         main.Append(CXXFLAGS=['-stdlib=libc++'])
 533         main.Append(LIBS=['c++'])
 534
 535     # On FreeBSD we need libthr.
 536     if sys.platform.startswith('freebsd'):
 537         main.Append(LIBS=['thr'])
 538
 539     # We require clang >= 3.1, so there is no need to check any
 540     # versions here.
 541     if GetOption('with_ubsan'):
 542         if GetOption('with_asan'):
 543             main.Append(CCFLAGS=['-fsanitize=address,undefined',
 544                                  '-fno-omit-frame-pointer'],
 545                        LINKFLAGS='-fsanitize=address,undefined')
 546         else:
 547             main.Append(CCFLAGS='-fsanitize=undefined',
 548                         LINKFLAGS='-fsanitize=undefined')
 549
 550     elif GetOption('with_asan'):
 551         main.Append(CCFLAGS=['-fsanitize=address',
 552                              '-fno-omit-frame-pointer'],
 553                    LINKFLAGS='-fsanitize=address')
 554
 555 else:
 556     print(termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal, end=' ')
 557     print("Don't know what compiler options to use for your compiler.")
 558     print(termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX'])
 559     print(termcap.Yellow + '       version:' + termcap.Normal, end=' ')
 560     if not CXX_version:
 561         print(termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +
 562               termcap.Normal)
 563     else:
 564         print(CXX_version.replace('\n', '<nl>'))
 565     print("       If you're trying to use a compiler other than GCC")
 566     print("       or clang, there appears to be something wrong with your")
 567     print("       environment.")
 568     print("       ")
 569     print("       If you are trying to use a compiler other than those listed")
 570     print("       above you will need to ease fix SConstruct and ")
 571     print("       src/SConscript to support that compiler.")
 572     Exit(1)
 573
 574 # Set up common yacc/bison flags (needed for Ruby)
 575 main['YACCFLAGS'] = '-d'
 576 main['YACCHXXFILESUFFIX'] = '.hh'
 577
 578 # Do this after we save setting back, or else we'll tack on an
 579 # extra 'qdo' every time we run scons.
 580 if main['BATCH']:
 581     main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
 582     main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
 583     main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
 584     main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
 585     main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
 586
 587 if sys.platform == 'cygwin':
 588     # cygwin has some header file issues...
 589     main.Append(CCFLAGS=["-Wno-uninitialized"])
 590
 591 # Check for the protobuf compiler
 592 protoc_version = readCommand([main['PROTOC'], '--version'],
 593                              exception='').split()
 594
 595 # First two words should be "libprotoc x.y.z"
 596 if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
 597     print(termcap.Yellow + termcap.Bold +
 598         'Warning: Protocol buffer compiler (protoc) not found.\n' +
 599         '         Please install protobuf-compiler for tracing support.' +
 600         termcap.Normal)
 601     main['PROTOC'] = False
 602 else:
 603     # Based on the availability of the compress stream wrappers,
 604     # require 2.1.0
 605     min_protoc_version = '2.1.0'
 606     if compareVersions(protoc_version[1], min_protoc_version) < 0:
 607         print(termcap.Yellow + termcap.Bold +
 608             'Warning: protoc version', min_protoc_version,
 609             'or newer required.\n' +
 610             '         Installed version:', protoc_version[1],
 611             termcap.Normal)
 612         main['PROTOC'] = False
 613     else:
 614         # Attempt to determine the appropriate include path and
 615         # library path using pkg-config, that means we also need to
 616         # check for pkg-config. Note that it is possible to use
 617         # protobuf without the involvement of pkg-config. Later on we
 618         # check go a library config check and at that point the test
 619         # will fail if libprotobuf cannot be found.
 620         if readCommand(['pkg-config', '--version'], exception=''):
 621             try:
 622                 # Attempt to establish what linking flags to add for protobuf
 623                 # using pkg-config
 624                 main.ParseConfig('pkg-config --cflags --libs-only-L protobuf')
 625             except:
 626                 print(termcap.Yellow + termcap.Bold +
 627                     'Warning: pkg-config could not get protobuf flags.' +
 628                     termcap.Normal)
 629
 630
 631 # Check for 'timeout' from GNU coreutils. If present, regressions will
 632 # be run with a time limit. We require version 8.13 since we rely on
 633 # support for the '--foreground' option.
 634 if sys.platform.startswith('freebsd'):
 635     timeout_lines = readCommand(['gtimeout', '--version'],
 636                                 exception='').splitlines()
 637 else:
 638     timeout_lines = readCommand(['timeout', '--version'],
 639                                 exception='').splitlines()
 640 # Get the first line and tokenize it
 641 timeout_version = timeout_lines[0].split() if timeout_lines else []
 642 main['TIMEOUT'] =  timeout_version and \
 643     compareVersions(timeout_version[-1], '8.13') >= 0
 644
 645 # Add a custom Check function to test for structure members.
 646 def CheckMember(context, include, decl, member, include_quotes="<>"):
 647     context.Message("Checking for member %s in %s..." %
 648                     (member, decl))
 649     text = """
 650 #include %(header)s
 651 int main(){
 652   %(decl)s test;
 653   (void)test.%(member)s;
 654   return 0;
 655 };
 656 """ % { "header" : include_quotes[0] + include + include_quotes[1],
 657         "decl" : decl,
 658         "member" : member,
 659         }
 660
 661     ret = context.TryCompile(text, extension=".cc")
 662     context.Result(ret)
 663     return ret
 664
 665 # Platform-specific configuration.  Note again that we assume that all
 666 # builds under a given build root run on the same host platform.
 667 conf = Configure(main,
 668                  conf_dir = joinpath(build_root, '.scons_config'),
 669                  log_file = joinpath(build_root, 'scons_config.log'),
 670                  custom_tests = {
 671         'CheckMember' : CheckMember,
 672         })
 673
 674 # Check if we should compile a 64 bit binary on Mac OS X/Darwin
 675 try:
 676     import platform
 677     uname = platform.uname()
 678     if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
 679         if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
 680             main.Append(CCFLAGS=['-arch', 'x86_64'])
 681             main.Append(CFLAGS=['-arch', 'x86_64'])
 682             main.Append(LINKFLAGS=['-arch', 'x86_64'])
 683             main.Append(ASFLAGS=['-arch', 'x86_64'])
 684 except:
 685     pass
 686
 687 # Recent versions of scons substitute a "Null" object for Configure()
 688 # when configuration isn't necessary, e.g., if the "--help" option is
 689 # present.  Unfortuantely this Null object always returns false,
 690 # breaking all our configuration checks.  We replace it with our own
 691 # more optimistic null object that returns True instead.
 692 if not conf:
 693     def NullCheck(*args, **kwargs):
 694         return True
 695
 696     class NullConf:
 697         def __init__(self, env):
 698             self.env = env
 699         def Finish(self):
 700             return self.env
 701         def __getattr__(self, mname):
 702             return NullCheck
 703
 704     conf = NullConf(main)
 705
 706 # Cache build files in the supplied directory.
 707 if main['M5_BUILD_CACHE']:
 708     print('Using build cache located at', main['M5_BUILD_CACHE'])
 709     CacheDir(main['M5_BUILD_CACHE'])
 710
 711 main['USE_PYTHON'] = not GetOption('without_python')
 712 if main['USE_PYTHON']:
 713     # Find Python include and library directories for embedding the
 714     # interpreter. We rely on python-config to resolve the appropriate
 715     # includes and linker flags. ParseConfig does not seem to understand
 716     # the more exotic linker flags such as -Xlinker and -export-dynamic so
 717     # we add them explicitly below. If you want to link in an alternate
 718     # version of python, see above for instructions on how to invoke
 719     # scons with the appropriate PATH set.
 720
 721     python_config = find_first_prog(main['PYTHON_CONFIG'])
 722     if python_config is None:
 723         print("Error: can't find a suitable python-config, tried %s" % \
 724               main['PYTHON_CONFIG'])
 725         Exit(1)
 726
 727     print("Info: Using Python config: %s" % (python_config, ))
 728     py_includes = readCommand([python_config, '--includes'],
 729                               exception='').split()
 730     py_includes = filter(lambda s: match(r'.*\/include\/.*',s), py_includes)
 731     # Strip the -I from the include folders before adding them to the
 732     # CPPPATH
 733     py_includes = map(lambda s: s[2:] if s.startswith('-I') else s, py_includes)
 734     main.Append(CPPPATH=py_includes)
 735
 736     # Read the linker flags and split them into libraries and other link
 737     # flags. The libraries are added later through the call the CheckLib.
 738     py_ld_flags = readCommand([python_config, '--ldflags'],
 739         exception='').split()
 740     py_libs = []
 741     for lib in py_ld_flags:
 742          if not lib.startswith('-l'):
 743              main.Append(LINKFLAGS=[lib])
 744          else:
 745              lib = lib[2:]
 746              if lib not in py_libs:
 747                  py_libs.append(lib)
 748
 749     # verify that this stuff works
 750     if not conf.CheckHeader('Python.h', '<>'):
 751         print("Error: Check failed for Python.h header in", py_includes)
 752         print("Two possible reasons:")
 753         print("1. Python headers are not installed (You can install the "
 754               "package python-dev on Ubuntu and RedHat)")
 755         print("2. SCons is using a wrong C compiler. This can happen if "
 756               "CC has the wrong value.")
 757         print("CC = %s" % main['CC'])
 758         Exit(1)
 759
 760     for lib in py_libs:
 761         if not conf.CheckLib(lib):
 762             print("Error: can't find library %s required by python" % lib)
 763             Exit(1)
 764
 765 # On Solaris you need to use libsocket for socket ops
 766 if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
 767    if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
 768        print("Can't find library with socket calls (e.g. accept())")
 769        Exit(1)
 770
 771 # Check for zlib.  If the check passes, libz will be automatically
 772 # added to the LIBS environment variable.
 773 if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
 774     print('Error: did not find needed zlib compression library '
 775           'and/or zlib.h header file.')
 776     print('       Please install zlib and try again.')
 777     Exit(1)
 778
 779 # If we have the protobuf compiler, also make sure we have the
 780 # development libraries. If the check passes, libprotobuf will be
 781 # automatically added to the LIBS environment variable. After
 782 # this, we can use the HAVE_PROTOBUF flag to determine if we have
 783 # got both protoc and libprotobuf available.
 784 main['HAVE_PROTOBUF'] = main['PROTOC'] and \
 785     conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
 786                             'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
 787
 788 # Valgrind gets much less confused if you tell it when you're using
 789 # alternative stacks.
 790 main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
 791
 792 # If we have the compiler but not the library, print another warning.
 793 if main['PROTOC'] and not main['HAVE_PROTOBUF']:
 794     print(termcap.Yellow + termcap.Bold +
 795         'Warning: did not find protocol buffer library and/or headers.\n' +
 796     '       Please install libprotobuf-dev for tracing support.' +
 797     termcap.Normal)
 798
 799 # Check for librt.
 800 have_posix_clock = \
 801     conf.CheckLibWithHeader(None, 'time.h', 'C',
 802                             'clock_nanosleep(0,0,NULL,NULL);') or \
 803     conf.CheckLibWithHeader('rt', 'time.h', 'C',
 804                             'clock_nanosleep(0,0,NULL,NULL);')
 805
 806 have_posix_timers = \
 807     conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
 808                             'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
 809
 810 if not GetOption('without_tcmalloc'):
 811     if conf.CheckLib('tcmalloc'):
 812         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 813     elif conf.CheckLib('tcmalloc_minimal'):
 814         main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
 815     else:
 816         print(termcap.Yellow + termcap.Bold +
 817               "You can get a 12% performance improvement by "
 818               "installing tcmalloc (libgoogle-perftools-dev package "
 819               "on Ubuntu or RedHat)." + termcap.Normal)
 820
 821
 822 # Detect back trace implementations. The last implementation in the
 823 # list will be used by default.
 824 backtrace_impls = [ "none" ]
 825
 826 backtrace_checker = 'char temp;' + \
 827     ' backtrace_symbols_fd((void*)&temp, 0, 0);'
 828 if conf.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker):
 829     backtrace_impls.append("glibc")
 830 elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
 831                              backtrace_checker):
 832     # NetBSD and FreeBSD need libexecinfo.
 833     backtrace_impls.append("glibc")
 834     main.Append(LIBS=['execinfo'])
 835
 836 if backtrace_impls[-1] == "none":
 837     default_backtrace_impl = "none"
 838     print(termcap.Yellow + termcap.Bold +
 839         "No suitable back trace implementation found." +
 840         termcap.Normal)
 841
 842 if not have_posix_clock:
 843     print("Can't find library for POSIX clocks.")
 844
 845 # Check for <fenv.h> (C99 FP environment control)
 846 have_fenv = conf.CheckHeader('fenv.h', '<>')
 847 if not have_fenv:
 848     print("Warning: Header file <fenv.h> not found.")
 849     print("         This host has no IEEE FP rounding mode control.")
 850
 851 # Check for <png.h> (libpng library needed if wanting to dump
 852 # frame buffer image in png format)
 853 have_png = conf.CheckHeader('png.h', '<>')
 854 if not have_png:
 855     print("Warning: Header file <png.h> not found.")
 856     print("         This host has no libpng library.")
 857     print("         Disabling support for PNG framebuffers.")
 858
 859 # Check if we should enable KVM-based hardware virtualization. The API
 860 # we rely on exists since version 2.6.36 of the kernel, but somehow
 861 # the KVM_API_VERSION does not reflect the change. We test for one of
 862 # the types as a fall back.
 863 have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
 864 if not have_kvm:
 865     print("Info: Compatible header file <linux/kvm.h> not found, "
 866           "disabling KVM support.")
 867
 868 # Check if the TUN/TAP driver is available.
 869 have_tuntap = conf.CheckHeader('linux/if_tun.h', '<>')
 870 if not have_tuntap:
 871     print("Info: Compatible header file <linux/if_tun.h> not found.")
 872
 873 # x86 needs support for xsave. We test for the structure here since we
 874 # won't be able to run new tests by the time we know which ISA we're
 875 # targeting.
 876 have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
 877                                     '#include <linux/kvm.h>') != 0
 878
 879 # Check if the requested target ISA is compatible with the host
 880 def is_isa_kvm_compatible(isa):
 881     try:
 882         import platform
 883         host_isa = platform.machine()
 884     except:
 885         print("Warning: Failed to determine host ISA.")
 886         return False
 887
 888     if not have_posix_timers:
 889         print("Warning: Can not enable KVM, host seems to lack support "
 890               "for POSIX timers")
 891         return False
 892
 893     if isa == "arm":
 894         return host_isa in ( "armv7l", "aarch64" )
 895     elif isa == "x86":
 896         if host_isa != "x86_64":
 897             return False
 898
 899         if not have_kvm_xsave:
 900             print("KVM on x86 requires xsave support in kernel headers.")
 901             return False
 902
 903         return True
 904     else:
 905         return False
 906
 907
 908 # Check if the exclude_host attribute is available. We want this to
 909 # get accurate instruction counts in KVM.
 910 main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
 911     'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
 912
 913
 914 ######################################################################
 915 #
 916 # Finish the configuration
 917 #
 918 main = conf.Finish()
 919
 920 ######################################################################
 921 #
 922 # Collect all non-global variables
 923 #
 924
 925 # Define the universe of supported ISAs
 926 all_isa_list = [ ]
 927 all_gpu_isa_list = [ ]
 928 Export('all_isa_list')
 929 Export('all_gpu_isa_list')
 930
 931 class CpuModel(object):
 932     '''The CpuModel class encapsulates everything the ISA parser needs to
 933     know about a particular CPU model.'''
 934
 935     # Dict of available CPU model objects.  Accessible as CpuModel.dict.
 936     dict = {}
 937
 938     # Constructor.  Automatically adds models to CpuModel.dict.
 939     def __init__(self, name, default=False):
 940         self.name = name           # name of model
 941
 942         # This cpu is enabled by default
 943         self.default = default
 944
 945         # Add self to dict
 946         if name in CpuModel.dict:
 947             raise AttributeError, "CpuModel '%s' already registered" % name
 948         CpuModel.dict[name] = self
 949
 950 Export('CpuModel')
 951
 952 # Sticky variables get saved in the variables file so they persist from
 953 # one invocation to the next (unless overridden, in which case the new
 954 # value becomes sticky).
 955 sticky_vars = Variables(args=ARGUMENTS)
 956 Export('sticky_vars')
 957
 958 # Sticky variables that should be exported
 959 export_vars = []
 960 Export('export_vars')
 961
 962 # For Ruby
 963 all_protocols = []
 964 Export('all_protocols')
 965 protocol_dirs = []
 966 Export('protocol_dirs')
 967 slicc_includes = []
 968 Export('slicc_includes')
 969
 970 # Walk the tree and execute all SConsopts scripts that wil add to the
 971 # above variables
 972 if GetOption('verbose'):
 973     print("Reading SConsopts")
 974 for bdir in [ base_dir ] + extras_dir_list:
 975     if not isdir(bdir):
 976         print("Error: directory '%s' does not exist" % bdir)
 977         Exit(1)
 978     for root, dirs, files in os.walk(bdir):
 979         if 'SConsopts' in files:
 980             if GetOption('verbose'):
 981                 print("Reading", joinpath(root, 'SConsopts'))
 982             SConscript(joinpath(root, 'SConsopts'))
 983
 984 all_isa_list.sort()
 985 all_gpu_isa_list.sort()
 986
 987 sticky_vars.AddVariables(
 988     EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
 989     EnumVariable('TARGET_GPU_ISA', 'Target GPU ISA', 'hsail', all_gpu_isa_list),
 990     ListVariable('CPU_MODELS', 'CPU models',
 991                  sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
 992                  sorted(CpuModel.dict.keys())),
 993     BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
 994                  False),
 995     BoolVariable('SS_COMPATIBLE_FP',
 996                  'Make floating-point results compatible with SimpleScalar',
 997                  False),
 998     BoolVariable('USE_SSE2',
 999                  'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
1000                  False),
1001     BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
1002     BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
1003     BoolVariable('USE_PNG',  'Enable support for PNG images', have_png),
1004     BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability',
1005                  False),
1006     BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models',
1007                  have_kvm),
1008     BoolVariable('USE_TUNTAP',
1009                  'Enable using a tap device to bridge to the host network',
1010                  have_tuntap),
1011     BoolVariable('BUILD_GPU', 'Build the compute-GPU model', False),
1012     EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1013                   all_protocols),
1014     EnumVariable('BACKTRACE_IMPL', 'Post-mortem dump implementation',
1015                  backtrace_impls[-1], backtrace_impls)
1016     )
1017
1018 # These variables get exported to #defines in config/*.hh (see src/SConscript).
1019 export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'TARGET_GPU_ISA',
1020                 'CP_ANNOTATE', 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP',
1021                 'PROTOCOL', 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
1022                 'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG']
1023
1024 ###################################################
1025 #
1026 # Define a SCons builder for configuration flag headers.
1027 #
1028 ###################################################
1029
1030 # This function generates a config header file that #defines the
1031 # variable symbol to the current variable setting (0 or 1).  The source
1032 # operands are the name of the variable and a Value node containing the
1033 # value of the variable.
1034 def build_config_file(target, source, env):
1035     (variable, value) = [s.get_contents() for s in source]
1036     f = file(str(target[0]), 'w')
1037     print('#define', variable, value, file=f)
1038     f.close()
1039     return None
1040
1041 # Combine the two functions into a scons Action object.
1042 config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1043
1044 # The emitter munges the source & target node lists to reflect what
1045 # we're really doing.
1046 def config_emitter(target, source, env):
1047     # extract variable name from Builder arg
1048     variable = str(target[0])
1049     # True target is config header file
1050     target = joinpath('config', variable.lower() + '.hh')
1051     val = env[variable]
1052     if isinstance(val, bool):
1053         # Force value to 0/1
1054         val = int(val)
1055     elif isinstance(val, str):
1056         val = '"' + val + '"'
1057
1058     # Sources are variable name & value (packaged in SCons Value nodes)
1059     return ([target], [Value(variable), Value(val)])
1060
1061 config_builder = Builder(emitter = config_emitter, action = config_action)
1062
1063 main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1064
1065 ###################################################
1066 #
1067 # Builders for static and shared partially linked object files.
1068 #
1069 ###################################################
1070
1071 partial_static_builder = Builder(action=SCons.Defaults.LinkAction,
1072                                  src_suffix='$OBJSUFFIX',
1073                                  src_builder=['StaticObject', 'Object'],
1074                                  LINKFLAGS='$PLINKFLAGS',
1075                                  LIBS='')
1076
1077 def partial_shared_emitter(target, source, env):
1078     for tgt in target:
1079         tgt.attributes.shared = 1
1080     return (target, source)
1081 partial_shared_builder = Builder(action=SCons.Defaults.ShLinkAction,
1082                                  emitter=partial_shared_emitter,
1083                                  src_suffix='$SHOBJSUFFIX',
1084                                  src_builder='SharedObject',
1085                                  SHLINKFLAGS='$PSHLINKFLAGS',
1086                                  LIBS='')
1087
1088 main.Append(BUILDERS = { 'PartialShared' : partial_shared_builder,
1089                          'PartialStatic' : partial_static_builder })
1090
1091 def add_local_rpath(env, *targets):
1092     '''Set up an RPATH for a library which lives in the build directory.
1093
1094     The construction environment variable BIN_RPATH_PREFIX should be set to
1095     the relative path of the build directory starting from the location of the
1096     binary.'''
1097     for target in targets:
1098         target = env.Entry(target)
1099         if not target.isdir():
1100             target = target.dir
1101         relpath = os.path.relpath(target.abspath, env['BUILDDIR'])
1102         components = [
1103             '\\$$ORIGIN',
1104             '${BIN_RPATH_PREFIX}',
1105             relpath
1106         ]
1107         env.Append(RPATH=[env.Literal(os.path.join(*components))])
1108
1109 if sys.platform != "darwin":
1110     main.Append(LINKFLAGS=Split('-z origin'))
1111
1112 main.AddMethod(add_local_rpath, 'AddLocalRPATH')
1113
1114 # builds in ext are shared across all configs in the build root.
1115 ext_dir = abspath(joinpath(str(main.root), 'ext'))
1116 ext_build_dirs = []
1117 for root, dirs, files in os.walk(ext_dir):
1118     if 'SConscript' in files:
1119         build_dir = os.path.relpath(root, ext_dir)
1120         ext_build_dirs.append(build_dir)
1121         main.SConscript(joinpath(root, 'SConscript'),
1122                         variant_dir=joinpath(build_root, build_dir))
1123
1124 gdb_xml_dir = joinpath(ext_dir, 'gdb-xml')
1125 Export('gdb_xml_dir')
1126
1127 main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
1128
1129 ###################################################
1130 #
1131 # This builder and wrapper method are used to set up a directory with
1132 # switching headers. Those are headers which are in a generic location and
1133 # that include more specific headers from a directory chosen at build time
1134 # based on the current build settings.
1135 #
1136 ###################################################
1137
1138 def build_switching_header(target, source, env):
1139     path = str(target[0])
1140     subdir = str(source[0])
1141     dp, fp = os.path.split(path)
1142     dp = os.path.relpath(os.path.realpath(dp),
1143                          os.path.realpath(env['BUILDDIR']))
1144     with open(path, 'w') as hdr:
1145         print('#include "%s/%s/%s"' % (dp, subdir, fp), file=hdr)
1146
1147 switching_header_action = MakeAction(build_switching_header,
1148                                      Transform('GENERATE'))
1149
1150 switching_header_builder = Builder(action=switching_header_action,
1151                                    source_factory=Value,
1152                                    single_source=True)
1153
1154 main.Append(BUILDERS = { 'SwitchingHeader': switching_header_builder })
1155
1156 def switching_headers(self, headers, source):
1157     for header in headers:
1158         self.SwitchingHeader(header, source)
1159
1160 main.AddMethod(switching_headers, 'SwitchingHeaders')
1161
1162 ###################################################
1163 #
1164 # Define build environments for selected configurations.
1165 #
1166 ###################################################
1167
1168 for variant_path in variant_paths:
1169     if not GetOption('silent'):
1170         print("Building in", variant_path)
1171
1172     # Make a copy of the build-root environment to use for this config.
1173     env = main.Clone()
1174     env['BUILDDIR'] = variant_path
1175
1176     # variant_dir is the tail component of build path, and is used to
1177     # determine the build parameters (e.g., 'ALPHA_SE')
1178     (build_root, variant_dir) = splitpath(variant_path)
1179
1180     # Set env variables according to the build directory config.
1181     sticky_vars.files = []
1182     # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1183     # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1184     # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1185     current_vars_file = joinpath(build_root, 'variables', variant_dir)
1186     if isfile(current_vars_file):
1187         sticky_vars.files.append(current_vars_file)
1188         if not GetOption('silent'):
1189             print("Using saved variables file %s" % current_vars_file)
1190     elif variant_dir in ext_build_dirs:
1191         # Things in ext are built without a variant directory.
1192         continue
1193     else:
1194         # Build dir-specific variables file doesn't exist.
1195
1196         # Make sure the directory is there so we can create it later
1197         opt_dir = dirname(current_vars_file)
1198         if not isdir(opt_dir):
1199             mkdir(opt_dir)
1200
1201         # Get default build variables from source tree.  Variables are
1202         # normally determined by name of $VARIANT_DIR, but can be
1203         # overridden by '--default=' arg on command line.
1204         default = GetOption('default')
1205         opts_dir = joinpath(main.root.abspath, 'build_opts')
1206         if default:
1207             default_vars_files = [joinpath(build_root, 'variables', default),
1208                                   joinpath(opts_dir, default)]
1209         else:
1210             default_vars_files = [joinpath(opts_dir, variant_dir)]
1211         existing_files = filter(isfile, default_vars_files)
1212         if existing_files:
1213             default_vars_file = existing_files[0]
1214             sticky_vars.files.append(default_vars_file)
1215             print("Variables file %s not found,\n  using defaults in %s"
1216                   % (current_vars_file, default_vars_file))
1217         else:
1218             print("Error: cannot find variables file %s or "
1219                   "default file(s) %s"
1220                   % (current_vars_file, ' or '.join(default_vars_files)))
1221             Exit(1)
1222
1223     # Apply current variable settings to env
1224     sticky_vars.Update(env)
1225
1226     help_texts["local_vars"] += \
1227         "Build variables for %s:\n" % variant_dir \
1228                  + sticky_vars.GenerateHelpText(env)
1229
1230     # Process variable settings.
1231
1232     if not have_fenv and env['USE_FENV']:
1233         print("Warning: <fenv.h> not available; "
1234               "forcing USE_FENV to False in", variant_dir + ".")
1235         env['USE_FENV'] = False
1236
1237     if not env['USE_FENV']:
1238         print("Warning: No IEEE FP rounding mode control in",
1239               variant_dir + ".")
1240         print("         FP results may deviate slightly from other platforms.")
1241
1242     if not have_png and env['USE_PNG']:
1243         print("Warning: <png.h> not available; "
1244               "forcing USE_PNG to False in", variant_dir + ".")
1245         env['USE_PNG'] = False
1246
1247     if env['USE_PNG']:
1248         env.Append(LIBS=['png'])
1249
1250     if env['EFENCE']:
1251         env.Append(LIBS=['efence'])
1252
1253     if env['USE_KVM']:
1254         if not have_kvm:
1255             print("Warning: Can not enable KVM, host seems to "
1256                   "lack KVM support")
1257             env['USE_KVM'] = False
1258         elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1259             print("Info: KVM support disabled due to unsupported host and "
1260                   "target ISA combination")
1261             env['USE_KVM'] = False
1262
1263     if env['USE_TUNTAP']:
1264         if not have_tuntap:
1265             print("Warning: Can't connect EtherTap with a tap device.")
1266             env['USE_TUNTAP'] = False
1267
1268     if env['BUILD_GPU']:
1269         env.Append(CPPDEFINES=['BUILD_GPU'])
1270
1271     # Warn about missing optional functionality
1272     if env['USE_KVM']:
1273         if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1274             print("Warning: perf_event headers lack support for the "
1275                   "exclude_host attribute. KVM instruction counts will "
1276                   "be inaccurate.")
1277
1278     # Save sticky variable settings back to current variables file
1279     sticky_vars.Save(current_vars_file, env)
1280
1281     if env['USE_SSE2']:
1282         env.Append(CCFLAGS=['-msse2'])
1283
1284     # The src/SConscript file sets up the build rules in 'env' according
1285     # to the configured variables.  It returns a list of environments,
1286     # one for each variant build (debug, opt, etc.)
1287     SConscript('src/SConscript', variant_dir = variant_path, exports = 'env')
1288
1289 # base help text
1290 Help('''
1291 Usage: scons [scons options] [build variables] [target(s)]
1292
1293 Extra scons options:
1294 %(options)s
1295
1296 Global build variables:
1297 %(global_vars)s
1298
1299 %(local_vars)s
1300 ''' % help_texts)