3 # Copyright (c) 2013, 2015-2020 ARM Limited
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.
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.
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.
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.
43 ###################################################
45 # SCons top-level build description (SConstruct) file.
47 # While in this directory ('gem5'), just type 'scons' to build the default
48 # configuration (see below), or type 'scons build/<CONFIG>/<binary>'
49 # to build some other configuration (e.g., 'build/X86/gem5.opt' for
50 # the optimized full-system version).
52 # You can build gem5 in a different directory as long as there is a
53 # 'build/<CONFIG>' somewhere along the target path. The build system
54 # expects that all configs under the same build directory are being
55 # built for the same host system.
59 # The following two commands are equivalent. The '-u' option tells
60 # scons to search up the directory tree for this SConstruct file.
61 # % cd <path-to-src>/gem5 ; scons build/X86/gem5.debug
62 # % cd <path-to-src>/gem5/build/X86; scons -u gem5.debug
64 # The following two commands are equivalent and demonstrate building
65 # in a directory outside of the source tree. The '-C' option tells
66 # scons to chdir to the specified directory to find this SConstruct
68 # % cd <path-to-src>/gem5 ; scons /local/foo/build/X86/gem5.debug
69 # % cd /local/foo/build/X86; scons -C <path-to-src>/gem5 gem5.debug
71 # You can use 'scons -H' to print scons options. If you're in this
72 # 'gem5' directory (or use -u or -C to tell scons where to find this
73 # file), you can use 'scons -h' to print all the gem5-specific build
76 ###################################################
78 from __future__
import print_function
80 # Global Python includes
89 from os
import mkdir
, environ
90 from os
.path
import abspath
, basename
, dirname
, expanduser
, normpath
91 from os
.path
import exists
, isdir
, isfile
92 from os
.path
import join
as joinpath
, split
as splitpath
100 from m5
.util
import compareVersions
, readCommand
, readCommandWithReturn
111 # There's a bug in scons in that (1) by default, the help texts from
112 # AddOption() are supposed to be displayed when you type 'scons -h'
113 # and (2) you can override the help displayed by 'scons -h' using the
114 # Help() function, but these two features are incompatible: once
115 # you've overridden the help text using Help(), there's no way to get
116 # at the help texts from AddOptions. See:
117 # http://scons.tigris.org/issues/show_bug.cgi?id=2356
118 # http://scons.tigris.org/issues/show_bug.cgi?id=2611
119 # This hack lets us extract the help text from AddOptions and
120 # re-inject it via Help(). Ideally someday this bug will be fixed and
121 # we can just use AddOption directly.
122 def AddLocalOption(*args
, **kwargs
):
125 help = " " + ", ".join(args
)
128 if length
>= col_width
:
129 help += "\n" + " " * col_width
131 help += " " * (col_width
- length
)
132 help += kwargs
["help"]
133 help_texts
["options"] += help + "\n"
135 AddOption(*args
, **kwargs
)
137 AddLocalOption('--colors', dest
='use_colors', action
='store_true',
138 help="Add color to abbreviated scons output")
139 AddLocalOption('--no-colors', dest
='use_colors', action
='store_false',
140 help="Don't add color to abbreviated scons output")
141 AddLocalOption('--with-cxx-config', dest
='with_cxx_config',
143 help="Build with support for C++-based configuration")
144 AddLocalOption('--default', dest
='default', type='string', action
='store',
145 help='Override which build_opts file to use for defaults')
146 AddLocalOption('--ignore-style', dest
='ignore_style', action
='store_true',
147 help='Disable style checking hooks')
148 AddLocalOption('--gold-linker', dest
='gold_linker', action
='store_true',
149 help='Use the gold linker')
150 AddLocalOption('--no-lto', dest
='no_lto', action
='store_true',
151 help='Disable Link-Time Optimization for fast')
152 AddLocalOption('--force-lto', dest
='force_lto', action
='store_true',
153 help='Use Link-Time Optimization instead of partial linking' +
154 ' when the compiler doesn\'t support using them together.')
155 AddLocalOption('--update-ref', dest
='update_ref', action
='store_true',
156 help='Update test reference outputs')
157 AddLocalOption('--verbose', dest
='verbose', action
='store_true',
158 help='Print full tool command lines')
159 AddLocalOption('--without-python', dest
='without_python',
161 help='Build without Python configuration support')
162 AddLocalOption('--without-tcmalloc', dest
='without_tcmalloc',
164 help='Disable linking against tcmalloc')
165 AddLocalOption('--with-ubsan', dest
='with_ubsan', action
='store_true',
166 help='Build with Undefined Behavior Sanitizer if available')
167 AddLocalOption('--with-asan', dest
='with_asan', action
='store_true',
168 help='Build with Address Sanitizer if available')
169 AddLocalOption('--with-systemc-tests', dest
='with_systemc_tests',
170 action
='store_true', help='Build systemc tests')
172 from gem5_scons
import Transform
, error
, warning
, summarize_warnings
174 if GetOption('no_lto') and GetOption('force_lto'):
175 error('--no-lto and --force-lto are mutually exclusive')
177 ########################################################################
179 # Set up the main build environment.
181 ########################################################################
185 from gem5_scons
.util
import get_termcap
186 termcap
= get_termcap()
188 main_dict_keys
= main
.Dictionary().keys()
190 # Check that we have a C/C++ compiler
191 if not ('CC' in main_dict_keys
and 'CXX' in main_dict_keys
):
192 error("No C++ compiler installed (package g++ on Ubuntu and RedHat)")
194 ###################################################
196 # Figure out which configurations to set up based on the path(s) of
199 ###################################################
201 # Find default configuration & binary.
202 Default(environ
.get('M5_DEFAULT_BINARY', 'build/ARM/gem5.debug'))
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):
209 raise ValueError("element not found")
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
))))
218 # Each target must have 'build' in the interior of the path; the
219 # directory below this will determine the build parameters. For
220 # example, for target 'foo/bar/build/X86/arch/x86/blah.do' we
221 # recognize that X86 specifies the configuration because it
222 # follow 'build' in the build path.
224 # The funky assignment to "[:]" is needed to replace the list contents
225 # in place rather than reassign the symbol to a new list, which
226 # doesn't work (obviously!).
227 BUILD_TARGETS
[:] = makePathListAbsolute(BUILD_TARGETS
)
229 # Generate a list of the unique build roots and configs that the
230 # collected targets reference.
233 for t
in BUILD_TARGETS
:
234 path_dirs
= t
.split('/')
236 build_top
= rfind(path_dirs
, 'build', -2)
238 error("No non-leaf 'build' dir found on target path.", t
)
239 this_build_root
= joinpath('/',*path_dirs
[:build_top
+1])
241 build_root
= this_build_root
243 if this_build_root
!= build_root
:
244 error("build targets not under same build root\n"
245 " %s\n %s" % (build_root
, this_build_root
))
246 variant_path
= joinpath('/',*path_dirs
[:build_top
+2])
247 if variant_path
not in variant_paths
:
248 variant_paths
.append(variant_path
)
250 # Make sure build_root exists (might not if this is the first build there)
251 if not isdir(build_root
):
253 main
['BUILDROOT'] = build_root
257 main
.SConsignFile(joinpath(build_root
, "sconsign"))
259 # Default duplicate option is to use hard links, but this messes up
260 # when you use emacs to edit a file in the target dir, as emacs moves
261 # file to file~ then copies to file, breaking the link. Symbolic
262 # (soft) links work better.
263 main
.SetOption('duplicate', 'soft-copy')
266 # Set up global sticky variables... these are common to an entire build
267 # tree (not specific to a particular build like X86)
270 global_vars_file
= joinpath(build_root
, 'variables.global')
272 global_vars
= Variables(global_vars_file
, args
=ARGUMENTS
)
274 global_vars
.AddVariables(
275 ('CC', 'C compiler', environ
.get('CC', main
['CC'])),
276 ('CXX', 'C++ compiler', environ
.get('CXX', main
['CXX'])),
277 ('CCFLAGS_EXTRA', 'Extra C and C++ compiler flags', ''),
278 ('LDFLAGS_EXTRA', 'Extra linker flags', ''),
279 ('PYTHON_CONFIG', 'Python config binary to use',
280 [ 'python2.7-config', 'python-config', 'python3-config' ]),
281 ('PROTOC', 'protoc tool', environ
.get('PROTOC', 'protoc')),
282 ('BATCH', 'Use batch pool for build and tests', False),
283 ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
284 ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
285 ('EXTRAS', 'Add extra directories to the compilation', '')
288 # Update main environment with values from ARGUMENTS & global_vars_file
289 global_vars
.Update(main
)
290 help_texts
["global_vars"] += global_vars
.GenerateHelpText(main
)
292 # Save sticky variable settings back to current variables file
293 global_vars
.Save(global_vars_file
, main
)
295 # Parse EXTRAS variable to build list of all directories where we're
296 # look for sources etc. This list is exported as extras_dir_list.
297 base_dir
= main
.srcdir
.abspath
299 extras_dir_list
= makePathListAbsolute(main
['EXTRAS'].split(':'))
304 Export('extras_dir_list')
306 # the ext directory should be on the #includes path
307 main
.Append(CPPPATH
=[Dir('ext')])
309 # Add shared top-level headers
310 main
.Prepend(CPPPATH
=Dir('include'))
312 if GetOption('verbose'):
313 def MakeAction(action
, string
, *args
, **kwargs
):
314 return Action(action
, *args
, **kwargs
)
317 main
['CCCOMSTR'] = Transform("CC")
318 main
['CXXCOMSTR'] = Transform("CXX")
319 main
['ASCOMSTR'] = Transform("AS")
320 main
['ARCOMSTR'] = Transform("AR", 0)
321 main
['LINKCOMSTR'] = Transform("LINK", 0)
322 main
['SHLINKCOMSTR'] = Transform("SHLINK", 0)
323 main
['RANLIBCOMSTR'] = Transform("RANLIB", 0)
324 main
['M4COMSTR'] = Transform("M4")
325 main
['SHCCCOMSTR'] = Transform("SHCC")
326 main
['SHCXXCOMSTR'] = Transform("SHCXX")
329 # Initialize the Link-Time Optimization (LTO) flags
330 main
['LTO_CCFLAGS'] = []
331 main
['LTO_LDFLAGS'] = []
333 # According to the readme, tcmalloc works best if the compiler doesn't
334 # assume that we're using the builtin malloc and friends. These flags
335 # are compiler-specific, so we need to set them after we detect which
336 # compiler we're using.
337 main
['TCMALLOC_CCFLAGS'] = []
339 CXX_version
= readCommand([main
['CXX'],'--version'], exception
=False)
340 CXX_V
= readCommand([main
['CXX'],'-V'], exception
=False)
342 main
['GCC'] = CXX_version
and CXX_version
.find('g++') >= 0
343 main
['CLANG'] = CXX_version
and CXX_version
.find('clang') >= 0
344 if main
['GCC'] + main
['CLANG'] > 1:
345 error('Two compilers enabled at once?')
347 # Set up default C++ compiler flags
348 if main
['GCC'] or main
['CLANG']:
349 # As gcc and clang share many flags, do the common parts here
350 main
.Append(CCFLAGS
=['-pipe'])
351 main
.Append(CCFLAGS
=['-fno-strict-aliasing'])
352 # Enable -Wall and -Wextra and then disable the few warnings that
353 # we consistently violate
354 main
.Append(CCFLAGS
=['-Wall', '-Wundef', '-Wextra',
355 '-Wno-sign-compare', '-Wno-unused-parameter'])
356 # We always compile using C++11
357 main
.Append(CXXFLAGS
=['-std=c++11'])
358 if sys
.platform
.startswith('freebsd'):
359 main
.Append(CCFLAGS
=['-I/usr/local/include'])
360 main
.Append(CXXFLAGS
=['-I/usr/local/include'])
362 # On Mac OS X/Darwin the default linker doesn't support the
364 if sys
.platform
!= "darwin":
365 main
.Append(LINKFLAGS
='-Wl,--as-needed')
366 main
['FILTER_PSHLINKFLAGS'] = lambda x
: str(x
).replace(' -shared', '')
367 main
['PSHLINKFLAGS'] = main
.subst('${FILTER_PSHLINKFLAGS(SHLINKFLAGS)}')
368 if GetOption('gold_linker'):
369 main
.Append(LINKFLAGS
='-fuse-ld=gold')
370 main
['PLINKFLAGS'] = main
.get('LINKFLAGS')
371 shared_partial_flags
= ['-r', '-nostdlib']
372 main
.Append(PSHLINKFLAGS
=shared_partial_flags
)
373 main
.Append(PLINKFLAGS
=shared_partial_flags
)
375 # Treat warnings as errors but white list some warnings that we
376 # want to allow (e.g., deprecation warnings).
377 main
.Append(CCFLAGS
=['-Werror',
378 '-Wno-error=deprecated-declarations',
379 '-Wno-error=deprecated',
383 "Don't know what compiler options to use for your compiler.",
384 "compiler: " + main
['CXX'],
385 "version: " + CXX_version
.replace('\n', '<nl>') if
386 CXX_version
else 'COMMAND NOT FOUND!',
387 "If you're trying to use a compiler other than GCC",
388 "or clang, there appears to be something wrong with your",
391 "If you are trying to use a compiler other than those listed",
392 "above you will need to ease fix SConstruct and ",
393 "src/SConscript to support that compiler.")))
396 # Check for a supported version of gcc. >= 4.8 is chosen for its
397 # level of c++11 support. See
398 # http://gcc.gnu.org/projects/cxx0x.html for details.
399 gcc_version
= readCommand([main
['CXX'], '-dumpversion'], exception
=False)
400 if compareVersions(gcc_version
, "4.8") < 0:
401 error('gcc version 4.8 or newer required.\n'
402 'Installed version:', gcc_version
)
405 main
['GCC_VERSION'] = gcc_version
407 if compareVersions(gcc_version
, '4.9') >= 0:
408 # Incremental linking with LTO is currently broken in gcc versions
409 # 4.9 and above. A version where everything works completely hasn't
410 # yet been identified.
412 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548
413 main
['BROKEN_INCREMENTAL_LTO'] = True
414 if compareVersions(gcc_version
, '6.0') >= 0:
415 # gcc versions 6.0 and greater accept an -flinker-output flag which
416 # selects what type of output the linker should generate. This is
417 # necessary for incremental lto to work, but is also broken in
418 # current versions of gcc. It may not be necessary in future
419 # versions. We add it here since it might be, and as a reminder that
420 # it exists. It's excluded if lto is being forced.
422 # https://gcc.gnu.org/gcc-6/changes.html
423 # https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03161.html
424 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69866
425 if not GetOption('force_lto'):
426 main
.Append(PSHLINKFLAGS
='-flinker-output=rel')
427 main
.Append(PLINKFLAGS
='-flinker-output=rel')
429 disable_lto
= GetOption('no_lto')
430 if not disable_lto
and main
.get('BROKEN_INCREMENTAL_LTO', False) and \
431 not GetOption('force_lto'):
432 warning('Your compiler doesn\'t support incremental linking and lto '
433 'at the same time, so lto is being disabled. To force lto on '
434 'anyway, use the --force-lto option. That will disable '
438 # Add the appropriate Link-Time Optimization (LTO) flags
439 # unless LTO is explicitly turned off. Note that these flags
440 # are only used by the fast target.
442 # Pass the LTO flag when compiling to produce GIMPLE
443 # output, we merely create the flags here and only append
445 main
['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
447 # Use the same amount of jobs for LTO as we are running
449 main
['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
451 main
.Append(TCMALLOC_CCFLAGS
=['-fno-builtin-malloc', '-fno-builtin-calloc',
452 '-fno-builtin-realloc', '-fno-builtin-free'])
455 # Check for a supported version of clang, >= 3.1 is needed to
456 # support similar features as gcc 4.8. See
457 # http://clang.llvm.org/cxx_status.html for details
458 clang_version_re
= re
.compile(".* version (\d+\.\d+)")
459 clang_version_match
= clang_version_re
.search(CXX_version
)
460 if (clang_version_match
):
461 clang_version
= clang_version_match
.groups()[0]
462 if compareVersions(clang_version
, "3.1") < 0:
463 error('clang version 3.1 or newer required.\n'
464 'Installed version:', clang_version
)
466 error('Unable to determine clang version.')
468 # clang has a few additional warnings that we disable, extraneous
469 # parantheses are allowed due to Ruby's printing of the AST,
470 # finally self assignments are allowed as the generated CPU code
472 main
.Append(CCFLAGS
=['-Wno-parentheses',
474 # Some versions of libstdc++ (4.8?) seem to
475 # use struct hash and class hash
477 '-Wno-mismatched-tags',
479 if compareVersions(clang_version
, "10.0") >= 0:
480 main
.Append(CCFLAGS
=['-Wno-c99-designator'])
482 if compareVersions(clang_version
, "8.0") >= 0:
483 main
.Append(CCFLAGS
=['-Wno-defaulted-function-deleted'])
485 main
.Append(TCMALLOC_CCFLAGS
=['-fno-builtin'])
487 # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
488 # opposed to libstdc++, as the later is dated.
489 if sys
.platform
== "darwin":
490 main
.Append(CXXFLAGS
=['-stdlib=libc++'])
491 main
.Append(LIBS
=['c++'])
493 # On FreeBSD we need libthr.
494 if sys
.platform
.startswith('freebsd'):
495 main
.Append(LIBS
=['thr'])
497 # Add sanitizers flags
499 if GetOption('with_ubsan'):
500 # Only gcc >= 4.9 supports UBSan, so check both the version
501 # and the command-line option before adding the compiler and
503 if not main
['GCC'] or compareVersions(main
['GCC_VERSION'], '4.9') >= 0:
504 sanitizers
.append('undefined')
505 if GetOption('with_asan'):
506 # Available for gcc >= 4.8 or llvm >= 3.1 both a requirement
507 # by the build system
508 sanitizers
.append('address')
509 suppressions_file
= Dir('util').File('lsan-suppressions').get_abspath()
510 suppressions_opt
= 'suppressions=%s' % suppressions_file
511 main
['ENV']['LSAN_OPTIONS'] = ':'.join([suppressions_opt
,
512 'print_suppressions=0'])
514 warning('To suppress false positive leaks, set the LSAN_OPTIONS '
515 'environment variable to "%s" when running gem5' %
517 warning('LSAN_OPTIONS=suppressions=%s' % suppressions_opt
)
520 sanitizers
= ','.join(sanitizers
)
521 if main
['GCC'] or main
['CLANG']:
522 main
.Append(CCFLAGS
=['-fsanitize=%s' % sanitizers
,
523 '-fno-omit-frame-pointer'],
524 LINKFLAGS
='-fsanitize=%s' % sanitizers
)
526 warning("Don't know how to enable %s sanitizer(s) for your "
527 "compiler." % sanitizers
)
529 # Set up common yacc/bison flags (needed for Ruby)
530 main
['YACCFLAGS'] = '-d'
531 main
['YACCHXXFILESUFFIX'] = '.hh'
533 # Do this after we save setting back, or else we'll tack on an
534 # extra 'qdo' every time we run scons.
536 main
['CC'] = main
['BATCH_CMD'] + ' ' + main
['CC']
537 main
['CXX'] = main
['BATCH_CMD'] + ' ' + main
['CXX']
538 main
['AS'] = main
['BATCH_CMD'] + ' ' + main
['AS']
539 main
['AR'] = main
['BATCH_CMD'] + ' ' + main
['AR']
540 main
['RANLIB'] = main
['BATCH_CMD'] + ' ' + main
['RANLIB']
542 if sys
.platform
== 'cygwin':
543 # cygwin has some header file issues...
544 main
.Append(CCFLAGS
=["-Wno-uninitialized"])
547 have_pkg_config
= readCommand(['pkg-config', '--version'], exception
='')
549 # Check for the protobuf compiler
551 main
['HAVE_PROTOC'] = True
552 protoc_version
= readCommand([main
['PROTOC'], '--version']).split()
554 # First two words should be "libprotoc x.y.z"
555 if len(protoc_version
) < 2 or protoc_version
[0] != 'libprotoc':
556 warning('Protocol buffer compiler (protoc) not found.\n'
557 'Please install protobuf-compiler for tracing support.')
558 main
['HAVE_PROTOC'] = False
560 # Based on the availability of the compress stream wrappers,
562 min_protoc_version
= '2.1.0'
563 if compareVersions(protoc_version
[1], min_protoc_version
) < 0:
564 warning('protoc version', min_protoc_version
,
565 'or newer required.\n'
566 'Installed version:', protoc_version
[1])
567 main
['HAVE_PROTOC'] = False
569 # Attempt to determine the appropriate include path and
570 # library path using pkg-config, that means we also need to
571 # check for pkg-config. Note that it is possible to use
572 # protobuf without the involvement of pkg-config. Later on we
573 # check go a library config check and at that point the test
574 # will fail if libprotobuf cannot be found.
577 # Attempt to establish what linking flags to add for
581 'pkg-config --cflags --libs-only-L protobuf')
583 warning('pkg-config could not get protobuf flags.')
584 except Exception as e
:
585 warning('While checking protoc version:', str(e
))
586 main
['HAVE_PROTOC'] = False
588 # Check for 'timeout' from GNU coreutils. If present, regressions will
589 # be run with a time limit. We require version 8.13 since we rely on
590 # support for the '--foreground' option.
591 if sys
.platform
.startswith('freebsd'):
592 timeout_lines
= readCommand(['gtimeout', '--version'],
593 exception
='').splitlines()
595 timeout_lines
= readCommand(['timeout', '--version'],
596 exception
='').splitlines()
597 # Get the first line and tokenize it
598 timeout_version
= timeout_lines
[0].split() if timeout_lines
else []
599 main
['TIMEOUT'] = timeout_version
and \
600 compareVersions(timeout_version
[-1], '8.13') >= 0
602 # Add a custom Check function to test for structure members.
603 def CheckMember(context
, include
, decl
, member
, include_quotes
="<>"):
604 context
.Message("Checking for member %s in %s..." %
610 (void)test.%(member)s;
613 """ % { "header" : include_quotes
[0] + include
+ include_quotes
[1],
618 ret
= context
.TryCompile(text
, extension
=".cc")
622 # Platform-specific configuration. Note again that we assume that all
623 # builds under a given build root run on the same host platform.
624 conf
= Configure(main
,
625 conf_dir
= joinpath(build_root
, '.scons_config'),
626 log_file
= joinpath(build_root
, 'scons_config.log'),
628 'CheckMember' : CheckMember
,
631 # Check if we should compile a 64 bit binary on Mac OS X/Darwin
634 uname
= platform
.uname()
635 if uname
[0] == 'Darwin' and compareVersions(uname
[2], '9.0.0') >= 0:
636 if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
637 main
.Append(CCFLAGS
=['-arch', 'x86_64'])
638 main
.Append(CFLAGS
=['-arch', 'x86_64'])
639 main
.Append(LINKFLAGS
=['-arch', 'x86_64'])
640 main
.Append(ASFLAGS
=['-arch', 'x86_64'])
644 # Recent versions of scons substitute a "Null" object for Configure()
645 # when configuration isn't necessary, e.g., if the "--help" option is
646 # present. Unfortuantely this Null object always returns false,
647 # breaking all our configuration checks. We replace it with our own
648 # more optimistic null object that returns True instead.
650 def NullCheck(*args
, **kwargs
):
654 def __init__(self
, env
):
658 def __getattr__(self
, mname
):
661 conf
= NullConf(main
)
663 # Cache build files in the supplied directory.
664 if main
['M5_BUILD_CACHE']:
665 print('Using build cache located at', main
['M5_BUILD_CACHE'])
666 CacheDir(main
['M5_BUILD_CACHE'])
668 main
['USE_PYTHON'] = not GetOption('without_python')
669 if main
['USE_PYTHON']:
670 # Find Python include and library directories for embedding the
671 # interpreter. We rely on python-config to resolve the appropriate
672 # includes and linker flags. ParseConfig does not seem to understand
673 # the more exotic linker flags such as -Xlinker and -export-dynamic so
674 # we add them explicitly below. If you want to link in an alternate
675 # version of python, see above for instructions on how to invoke
676 # scons with the appropriate PATH set.
678 python_config
= main
.Detect(main
['PYTHON_CONFIG'])
679 if python_config
is None:
680 error("Can't find a suitable python-config, tried %s" % \
681 main
['PYTHON_CONFIG'])
683 print("Info: Using Python config: %s" % (python_config
, ))
684 py_includes
= readCommand([python_config
, '--includes'],
685 exception
='').split()
686 py_includes
= list(filter(
687 lambda s
: match(r
'.*\/include\/.*',s
), py_includes
))
688 # Strip the -I from the include folders before adding them to the
690 py_includes
= list(map(
691 lambda s
: s
[2:] if s
.startswith('-I') else s
, py_includes
))
692 main
.Append(CPPPATH
=py_includes
)
694 # Read the linker flags and split them into libraries and other link
695 # flags. The libraries are added later through the call the CheckLib.
696 # Note: starting in Python 3.8 the --embed flag is required to get the
697 # -lpython3.8 linker flag
698 retcode
, cmd_stdout
= readCommandWithReturn(
699 [python_config
, '--ldflags', '--embed'], exception
='')
701 # If --embed isn't detected then we're running python <3.8
702 retcode
, cmd_stdout
= readCommandWithReturn(
703 [python_config
, '--ldflags'], exception
='')
705 # Checking retcode again
707 error("Failing on python-config --ldflags command")
709 py_ld_flags
= cmd_stdout
.split()
712 for lib
in py_ld_flags
:
713 if not lib
.startswith('-l'):
714 main
.Append(LINKFLAGS
=[lib
])
717 if lib
not in py_libs
:
720 # verify that this stuff works
721 if not conf
.CheckHeader('Python.h', '<>'):
722 error("Check failed for Python.h header in",
723 ' '.join(py_includes
), "\n"
724 "Two possible reasons:\n"
725 "1. Python headers are not installed (You can install the "
726 "package python-dev on Ubuntu and RedHat)\n"
727 "2. SCons is using a wrong C compiler. This can happen if "
728 "CC has the wrong value.\n"
729 "CC = %s" % main
['CC'])
732 if not conf
.CheckLib(lib
):
733 error("Can't find library %s required by python." % lib
)
735 main
.Prepend(CPPPATH
=Dir('ext/pybind11/include/'))
736 # Bare minimum environment that only includes python
737 base_py_env
= main
.Clone()
739 # On Solaris you need to use libsocket for socket ops
740 if not conf
.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
741 if not conf
.CheckLibWithHeader('socket', 'sys/socket.h',
742 'C++', 'accept(0,0,0);'):
743 error("Can't find library with socket calls (e.g. accept()).")
745 # Check for zlib. If the check passes, libz will be automatically
746 # added to the LIBS environment variable.
747 if not conf
.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
748 error('Did not find needed zlib compression library '
749 'and/or zlib.h header file.\n'
750 'Please install zlib and try again.')
752 # If we have the protobuf compiler, also make sure we have the
753 # development libraries. If the check passes, libprotobuf will be
754 # automatically added to the LIBS environment variable. After
755 # this, we can use the HAVE_PROTOBUF flag to determine if we have
756 # got both protoc and libprotobuf available.
757 main
['HAVE_PROTOBUF'] = main
['HAVE_PROTOC'] and \
758 conf
.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
759 'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
761 # Valgrind gets much less confused if you tell it when you're using
762 # alternative stacks.
763 main
['HAVE_VALGRIND'] = conf
.CheckCHeader('valgrind/valgrind.h')
765 # If we have the compiler but not the library, print another warning.
766 if main
['HAVE_PROTOC'] and not main
['HAVE_PROTOBUF']:
767 warning('Did not find protocol buffer library and/or headers.\n'
768 'Please install libprotobuf-dev for tracing support.')
772 conf
.CheckLibWithHeader(None, 'time.h', 'C',
773 'clock_nanosleep(0,0,NULL,NULL);') or \
774 conf
.CheckLibWithHeader('rt', 'time.h', 'C',
775 'clock_nanosleep(0,0,NULL,NULL);')
777 have_posix_timers
= \
778 conf
.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
779 'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
781 if not GetOption('without_tcmalloc'):
782 if conf
.CheckLib('tcmalloc'):
783 main
.Append(CCFLAGS
=main
['TCMALLOC_CCFLAGS'])
784 elif conf
.CheckLib('tcmalloc_minimal'):
785 main
.Append(CCFLAGS
=main
['TCMALLOC_CCFLAGS'])
787 warning("You can get a 12% performance improvement by "
788 "installing tcmalloc (libgoogle-perftools-dev package "
789 "on Ubuntu or RedHat).")
792 # Detect back trace implementations. The last implementation in the
793 # list will be used by default.
794 backtrace_impls
= [ "none" ]
796 backtrace_checker
= 'char temp;' + \
797 ' backtrace_symbols_fd((void*)&temp, 0, 0);'
798 if conf
.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker
):
799 backtrace_impls
.append("glibc")
800 elif conf
.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
802 # NetBSD and FreeBSD need libexecinfo.
803 backtrace_impls
.append("glibc")
804 main
.Append(LIBS
=['execinfo'])
806 if backtrace_impls
[-1] == "none":
807 default_backtrace_impl
= "none"
808 warning("No suitable back trace implementation found.")
810 if not have_posix_clock
:
811 warning("Can't find library for POSIX clocks.")
813 # Check for <fenv.h> (C99 FP environment control)
814 have_fenv
= conf
.CheckHeader('fenv.h', '<>')
816 warning("Header file <fenv.h> not found.\n"
817 "This host has no IEEE FP rounding mode control.")
819 # Check for <png.h> (libpng library needed if wanting to dump
820 # frame buffer image in png format)
821 have_png
= conf
.CheckHeader('png.h', '<>')
823 warning("Header file <png.h> not found.\n"
824 "This host has no libpng library.\n"
825 "Disabling support for PNG framebuffers.")
827 # Check if we should enable KVM-based hardware virtualization. The API
828 # we rely on exists since version 2.6.36 of the kernel, but somehow
829 # the KVM_API_VERSION does not reflect the change. We test for one of
830 # the types as a fall back.
831 have_kvm
= conf
.CheckHeader('linux/kvm.h', '<>')
833 print("Info: Compatible header file <linux/kvm.h> not found, "
834 "disabling KVM support.")
836 # Check if the TUN/TAP driver is available.
837 have_tuntap
= conf
.CheckHeader('linux/if_tun.h', '<>')
839 print("Info: Compatible header file <linux/if_tun.h> not found.")
841 # x86 needs support for xsave. We test for the structure here since we
842 # won't be able to run new tests by the time we know which ISA we're
844 have_kvm_xsave
= conf
.CheckTypeSize('struct kvm_xsave',
845 '#include <linux/kvm.h>') != 0
847 # Check if the requested target ISA is compatible with the host
848 def is_isa_kvm_compatible(isa
):
851 host_isa
= platform
.machine()
853 warning("Failed to determine host ISA.")
856 if not have_posix_timers
:
857 warning("Can not enable KVM, host seems to lack support "
862 return host_isa
in ( "armv7l", "aarch64" )
864 if host_isa
!= "x86_64":
867 if not have_kvm_xsave
:
868 warning("KVM on x86 requires xsave support in kernel headers.")
876 # Check if the exclude_host attribute is available. We want this to
877 # get accurate instruction counts in KVM.
878 main
['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf
.CheckMember(
879 'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
883 conf
.CheckLibWithHeader('hdf5', 'hdf5.h', 'C',
884 'H5Fcreate("", 0, 0, 0);') and \
885 conf
.CheckLibWithHeader('hdf5_cpp', 'H5Cpp.h', 'C++',
886 'H5::H5File("", 0);')
888 def check_hdf5_pkg(name
):
889 print("Checking for %s using pkg-config..." % name
, end
="")
890 if not have_pkg_config
:
891 print(" pkg-config not found")
895 main
.ParseConfig('pkg-config --cflags-only-I --libs-only-L %s' % name
)
902 # Check if there is a pkg-config configuration for hdf5. If we find
903 # it, setup the environment to enable linking and header inclusion. We
904 # don't actually try to include any headers or link with hdf5 at this
906 if not check_hdf5_pkg('hdf5-serial'):
907 check_hdf5_pkg('hdf5')
909 # Check if the HDF5 libraries can be found. This check respects the
910 # include path and library path provided by pkg-config. We perform
911 # this check even if there isn't a pkg-config configuration for hdf5
912 # since some installations don't use pkg-config.
913 have_hdf5
= check_hdf5()
915 print("Warning: Couldn't find any HDF5 C++ libraries. Disabling")
916 print(" HDF5 support.")
918 ######################################################################
920 # Finish the configuration
924 ######################################################################
926 # Collect all non-global variables
929 # Define the universe of supported ISAs
931 all_gpu_isa_list
= [ ]
932 Export('all_isa_list')
933 Export('all_gpu_isa_list')
935 class CpuModel(object):
936 '''The CpuModel class encapsulates everything the ISA parser needs to
937 know about a particular CPU model.'''
939 # Dict of available CPU model objects. Accessible as CpuModel.dict.
942 # Constructor. Automatically adds models to CpuModel.dict.
943 def __init__(self
, name
, default
=False):
944 self
.name
= name
# name of model
946 # This cpu is enabled by default
947 self
.default
= default
950 if name
in CpuModel
.dict:
951 raise AttributeError("CpuModel '%s' already registered" % name
)
952 CpuModel
.dict[name
] = self
956 # Sticky variables get saved in the variables file so they persist from
957 # one invocation to the next (unless overridden, in which case the new
958 # value becomes sticky).
959 sticky_vars
= Variables(args
=ARGUMENTS
)
960 Export('sticky_vars')
962 # Sticky variables that should be exported
964 Export('export_vars')
968 Export('all_protocols')
970 Export('protocol_dirs')
972 Export('slicc_includes')
974 # Walk the tree and execute all SConsopts scripts that wil add to the
976 if GetOption('verbose'):
977 print("Reading SConsopts")
978 for bdir
in [ base_dir
] + extras_dir_list
:
980 error("Directory '%s' does not exist." % bdir
)
981 for root
, dirs
, files
in os
.walk(bdir
):
982 if 'SConsopts' in files
:
983 if GetOption('verbose'):
984 print("Reading", joinpath(root
, 'SConsopts'))
985 SConscript(joinpath(root
, 'SConsopts'))
988 all_gpu_isa_list
.sort()
990 sticky_vars
.AddVariables(
991 EnumVariable('TARGET_ISA', 'Target ISA', 'null', all_isa_list
),
992 EnumVariable('TARGET_GPU_ISA', 'Target GPU ISA', 'hsail', all_gpu_isa_list
),
993 ListVariable('CPU_MODELS', 'CPU models',
994 sorted(n
for n
,m
in CpuModel
.dict.items() if m
.default
),
995 sorted(CpuModel
.dict.keys())),
996 BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
998 BoolVariable('USE_SSE2',
999 'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
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',
1006 BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models',
1008 BoolVariable('USE_TUNTAP',
1009 'Enable using a tap device to bridge to the host network',
1011 BoolVariable('BUILD_GPU', 'Build the compute-GPU model', False),
1012 EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1014 EnumVariable('BACKTRACE_IMPL', 'Post-mortem dump implementation',
1015 backtrace_impls
[-1], backtrace_impls
),
1016 ('NUMBER_BITS_PER_SET', 'Max elements in set (default 64)',
1018 BoolVariable('USE_HDF5', 'Enable the HDF5 support', have_hdf5
),
1021 # These variables get exported to #defines in config/*.hh (see src/SConscript).
1022 export_vars
+= ['USE_FENV', 'TARGET_ISA', 'TARGET_GPU_ISA', 'CP_ANNOTATE',
1023 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP', 'PROTOCOL',
1024 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
1025 'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG',
1026 'NUMBER_BITS_PER_SET', 'USE_HDF5']
1028 ###################################################
1030 # Define a SCons builder for configuration flag headers.
1032 ###################################################
1034 # This function generates a config header file that #defines the
1035 # variable symbol to the current variable setting (0 or 1). The source
1036 # operands are the name of the variable and a Value node containing the
1037 # value of the variable.
1038 def build_config_file(target
, source
, env
):
1039 (variable
, value
) = [s
.get_contents().decode('utf-8') for s
in source
]
1040 with
open(str(target
[0]), 'w') as f
:
1041 print('#define', variable
, value
, file=f
)
1044 # Combine the two functions into a scons Action object.
1045 config_action
= MakeAction(build_config_file
, Transform("CONFIG H", 2))
1047 # The emitter munges the source & target node lists to reflect what
1048 # we're really doing.
1049 def config_emitter(target
, source
, env
):
1050 # extract variable name from Builder arg
1051 variable
= str(target
[0])
1052 # True target is config header file
1053 target
= joinpath('config', variable
.lower() + '.hh')
1055 if isinstance(val
, bool):
1056 # Force value to 0/1
1058 elif isinstance(val
, str):
1059 val
= '"' + val
+ '"'
1061 # Sources are variable name & value (packaged in SCons Value nodes)
1062 return ([target
], [Value(variable
), Value(val
)])
1064 config_builder
= Builder(emitter
= config_emitter
, action
= config_action
)
1066 main
.Append(BUILDERS
= { 'ConfigFile' : config_builder
})
1068 ###################################################
1070 # Builders for static and shared partially linked object files.
1072 ###################################################
1074 partial_static_builder
= Builder(action
=SCons
.Defaults
.LinkAction
,
1075 src_suffix
='$OBJSUFFIX',
1076 src_builder
=['StaticObject', 'Object'],
1077 LINKFLAGS
='$PLINKFLAGS',
1080 def partial_shared_emitter(target
, source
, env
):
1082 tgt
.attributes
.shared
= 1
1083 return (target
, source
)
1084 partial_shared_builder
= Builder(action
=SCons
.Defaults
.ShLinkAction
,
1085 emitter
=partial_shared_emitter
,
1086 src_suffix
='$SHOBJSUFFIX',
1087 src_builder
='SharedObject',
1088 SHLINKFLAGS
='$PSHLINKFLAGS',
1091 main
.Append(BUILDERS
= { 'PartialShared' : partial_shared_builder
,
1092 'PartialStatic' : partial_static_builder
})
1094 def add_local_rpath(env
, *targets
):
1095 '''Set up an RPATH for a library which lives in the build directory.
1097 The construction environment variable BIN_RPATH_PREFIX should be set to
1098 the relative path of the build directory starting from the location of the
1100 for target
in targets
:
1101 target
= env
.Entry(target
)
1102 if not isinstance(target
, SCons
.Node
.FS
.Dir
):
1104 relpath
= os
.path
.relpath(target
.abspath
, env
['BUILDDIR'])
1107 '${BIN_RPATH_PREFIX}',
1110 env
.Append(RPATH
=[env
.Literal(os
.path
.join(*components
))])
1112 if sys
.platform
!= "darwin":
1113 main
.Append(LINKFLAGS
=Split('-z origin'))
1115 main
.AddMethod(add_local_rpath
, 'AddLocalRPATH')
1117 # builds in ext are shared across all configs in the build root.
1118 ext_dir
= abspath(joinpath(str(main
.root
), 'ext'))
1120 for root
, dirs
, files
in os
.walk(ext_dir
):
1121 if 'SConscript' in files
:
1122 build_dir
= os
.path
.relpath(root
, ext_dir
)
1123 ext_build_dirs
.append(build_dir
)
1124 main
.SConscript(joinpath(root
, 'SConscript'),
1125 variant_dir
=joinpath(build_root
, build_dir
))
1127 gdb_xml_dir
= joinpath(ext_dir
, 'gdb-xml')
1128 Export('gdb_xml_dir')
1130 ###################################################
1132 # This builder and wrapper method are used to set up a directory with
1133 # switching headers. Those are headers which are in a generic location and
1134 # that include more specific headers from a directory chosen at build time
1135 # based on the current build settings.
1137 ###################################################
1139 def build_switching_header(target
, source
, env
):
1140 path
= str(target
[0])
1141 subdir
= str(source
[0])
1142 dp
, fp
= os
.path
.split(path
)
1143 dp
= os
.path
.relpath(os
.path
.realpath(dp
),
1144 os
.path
.realpath(env
['BUILDDIR']))
1145 with
open(path
, 'w') as hdr
:
1146 print('#include "%s/%s/%s"' % (dp
, subdir
, fp
), file=hdr
)
1148 switching_header_action
= MakeAction(build_switching_header
,
1149 Transform('GENERATE'))
1151 switching_header_builder
= Builder(action
=switching_header_action
,
1152 source_factory
=Value
,
1155 main
.Append(BUILDERS
= { 'SwitchingHeader': switching_header_builder
})
1157 def switching_headers(self
, headers
, source
):
1158 for header
in headers
:
1159 self
.SwitchingHeader(header
, source
)
1161 main
.AddMethod(switching_headers
, 'SwitchingHeaders')
1163 ###################################################
1165 # Define build environments for selected configurations.
1167 ###################################################
1169 for variant_path
in variant_paths
:
1170 if not GetOption('silent'):
1171 print("Building in", variant_path
)
1173 # Make a copy of the build-root environment to use for this config.
1175 env
['BUILDDIR'] = variant_path
1177 # variant_dir is the tail component of build path, and is used to
1178 # determine the build parameters (e.g., 'X86')
1179 (build_root
, variant_dir
) = splitpath(variant_path
)
1181 # Set env variables according to the build directory config.
1182 sticky_vars
.files
= []
1183 # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1184 # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1185 # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1186 current_vars_file
= joinpath(build_root
, 'variables', variant_dir
)
1187 if isfile(current_vars_file
):
1188 sticky_vars
.files
.append(current_vars_file
)
1189 if not GetOption('silent'):
1190 print("Using saved variables file %s" % current_vars_file
)
1191 elif variant_dir
in ext_build_dirs
:
1192 # Things in ext are built without a variant directory.
1195 # Build dir-specific variables file doesn't exist.
1197 # Make sure the directory is there so we can create it later
1198 opt_dir
= dirname(current_vars_file
)
1199 if not isdir(opt_dir
):
1202 # Get default build variables from source tree. Variables are
1203 # normally determined by name of $VARIANT_DIR, but can be
1204 # overridden by '--default=' arg on command line.
1205 default
= GetOption('default')
1206 opts_dir
= joinpath(main
.root
.abspath
, 'build_opts')
1208 default_vars_files
= [joinpath(build_root
, 'variables', default
),
1209 joinpath(opts_dir
, default
)]
1211 default_vars_files
= [joinpath(opts_dir
, variant_dir
)]
1212 existing_files
= list(filter(isfile
, default_vars_files
))
1214 default_vars_file
= existing_files
[0]
1215 sticky_vars
.files
.append(default_vars_file
)
1216 print("Variables file %s not found,\n using defaults in %s"
1217 % (current_vars_file
, default_vars_file
))
1219 error("Cannot find variables file %s or default file(s) %s"
1220 % (current_vars_file
, ' or '.join(default_vars_files
)))
1223 # Apply current variable settings to env
1224 sticky_vars
.Update(env
)
1226 help_texts
["local_vars"] += \
1227 "Build variables for %s:\n" % variant_dir \
1228 + sticky_vars
.GenerateHelpText(env
)
1230 # Process variable settings.
1232 if not have_fenv
and env
['USE_FENV']:
1233 warning("<fenv.h> not available; forcing USE_FENV to False in",
1235 env
['USE_FENV'] = False
1237 if not env
['USE_FENV']:
1238 warning("No IEEE FP rounding mode control in", variant_dir
+ ".\n"
1239 "FP results may deviate slightly from other platforms.")
1241 if not have_png
and env
['USE_PNG']:
1242 warning("<png.h> not available; forcing USE_PNG to False in",
1244 env
['USE_PNG'] = False
1247 env
.Append(LIBS
=['png'])
1250 env
.Append(LIBS
=['efence'])
1254 warning("Can not enable KVM, host seems to lack KVM support")
1255 env
['USE_KVM'] = False
1256 elif not is_isa_kvm_compatible(env
['TARGET_ISA']):
1257 print("Info: KVM support disabled due to unsupported host and "
1258 "target ISA combination")
1259 env
['USE_KVM'] = False
1261 if env
['USE_TUNTAP']:
1263 warning("Can't connect EtherTap with a tap device.")
1264 env
['USE_TUNTAP'] = False
1266 if env
['BUILD_GPU']:
1267 env
.Append(CPPDEFINES
=['BUILD_GPU'])
1269 # Warn about missing optional functionality
1271 if not main
['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1272 warning("perf_event headers lack support for the exclude_host "
1273 "attribute. KVM instruction counts will be inaccurate.")
1275 # Save sticky variable settings back to current variables file
1276 sticky_vars
.Save(current_vars_file
, env
)
1279 env
.Append(CCFLAGS
=['-msse2'])
1281 env
.Append(CCFLAGS
='$CCFLAGS_EXTRA')
1282 env
.Append(LINKFLAGS
='$LDFLAGS_EXTRA')
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
,
1288 exports
=['env', 'base_py_env'])
1292 Usage: scons [scons options] [build variables] [target(s)]
1294 Extra scons options:
1297 Global build variables:
1303 atexit
.register(summarize_warnings
)