SConstruct revision 14209
1# -*- mode:python -*-
2
3# Copyright (c) 2013, 2015-2019 ARM Limited
4# All rights reserved.
5#
6# The license below extends only to copyright in the software and shall
7# not be construed as granting a license to any other intellectual
8# property including but not limited to intellectual property relating
9# to a hardware implementation of the functionality of the software
10# licensed hereunder.  You may use the software subject to the license
11# terms below provided that you ensure that this notice is replicated
12# unmodified and in its entirety in all distributions of the software,
13# modified or unmodified, in source code or in binary form.
14#
15# Copyright (c) 2011 Advanced Micro Devices, Inc.
16# Copyright (c) 2009 The Hewlett-Packard Development Company
17# Copyright (c) 2004-2005 The Regents of The University of Michigan
18# All rights reserved.
19#
20# Redistribution and use in source and binary forms, with or without
21# modification, are permitted provided that the following conditions are
22# met: redistributions of source code must retain the above copyright
23# notice, this list of conditions and the following disclaimer;
24# redistributions in binary form must reproduce the above copyright
25# notice, this list of conditions and the following disclaimer in the
26# documentation and/or other materials provided with the distribution;
27# neither the name of the copyright holders nor the names of its
28# contributors may be used to endorse or promote products derived from
29# this software without specific prior written permission.
30#
31# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
34# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
36# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
37# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
38# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
39# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
41# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42#
43# Authors: Steve Reinhardt
44#          Nathan Binkert
45
46###################################################
47#
48# SCons top-level build description (SConstruct) file.
49#
50# While in this directory ('gem5'), just type 'scons' to build the default
51# configuration (see below), or type 'scons build/<CONFIG>/<binary>'
52# to build some other configuration (e.g., 'build/ALPHA/gem5.opt' for
53# the optimized full-system version).
54#
55# You can build gem5 in a different directory as long as there is a
56# 'build/<CONFIG>' somewhere along the target path.  The build system
57# expects that all configs under the same build directory are being
58# built for the same host system.
59#
60# Examples:
61#
62#   The following two commands are equivalent.  The '-u' option tells
63#   scons to search up the directory tree for this SConstruct file.
64#   % cd <path-to-src>/gem5 ; scons build/ALPHA/gem5.debug
65#   % cd <path-to-src>/gem5/build/ALPHA; scons -u gem5.debug
66#
67#   The following two commands are equivalent and demonstrate building
68#   in a directory outside of the source tree.  The '-C' option tells
69#   scons to chdir to the specified directory to find this SConstruct
70#   file.
71#   % cd <path-to-src>/gem5 ; scons /local/foo/build/ALPHA/gem5.debug
72#   % cd /local/foo/build/ALPHA; scons -C <path-to-src>/gem5 gem5.debug
73#
74# You can use 'scons -H' to print scons options.  If you're in this
75# 'gem5' directory (or use -u or -C to tell scons where to find this
76# file), you can use 'scons -h' to print all the gem5-specific build
77# options as well.
78#
79###################################################
80
81from __future__ import print_function
82
83# Global Python includes
84import itertools
85import os
86import re
87import shutil
88import subprocess
89import sys
90
91from os import mkdir, environ
92from os.path import abspath, basename, dirname, expanduser, normpath
93from os.path import exists,  isdir, isfile
94from os.path import join as joinpath, split as splitpath
95from re import match
96
97# SCons includes
98import SCons
99import SCons.Node
100import SCons.Node.FS
101
102from m5.util import compareVersions, readCommand
103
104help_texts = {
105    "options" : "",
106    "global_vars" : "",
107    "local_vars" : ""
108}
109
110Export("help_texts")
111
112
113# There's a bug in scons in that (1) by default, the help texts from
114# AddOption() are supposed to be displayed when you type 'scons -h'
115# and (2) you can override the help displayed by 'scons -h' using the
116# Help() function, but these two features are incompatible: once
117# you've overridden the help text using Help(), there's no way to get
118# at the help texts from AddOptions.  See:
119#     http://scons.tigris.org/issues/show_bug.cgi?id=2356
120#     http://scons.tigris.org/issues/show_bug.cgi?id=2611
121# This hack lets us extract the help text from AddOptions and
122# re-inject it via Help().  Ideally someday this bug will be fixed and
123# we can just use AddOption directly.
124def AddLocalOption(*args, **kwargs):
125    col_width = 30
126
127    help = "  " + ", ".join(args)
128    if "help" in kwargs:
129        length = len(help)
130        if length >= col_width:
131            help += "\n" + " " * col_width
132        else:
133            help += " " * (col_width - length)
134        help += kwargs["help"]
135    help_texts["options"] += help + "\n"
136
137    AddOption(*args, **kwargs)
138
139AddLocalOption('--colors', dest='use_colors', action='store_true',
140               help="Add color to abbreviated scons output")
141AddLocalOption('--no-colors', dest='use_colors', action='store_false',
142               help="Don't add color to abbreviated scons output")
143AddLocalOption('--with-cxx-config', dest='with_cxx_config',
144               action='store_true',
145               help="Build with support for C++-based configuration")
146AddLocalOption('--default', dest='default', type='string', action='store',
147               help='Override which build_opts file to use for defaults')
148AddLocalOption('--ignore-style', dest='ignore_style', action='store_true',
149               help='Disable style checking hooks')
150AddLocalOption('--gold-linker', dest='gold_linker', action='store_true',
151               help='Use the gold linker')
152AddLocalOption('--no-lto', dest='no_lto', action='store_true',
153               help='Disable Link-Time Optimization for fast')
154AddLocalOption('--force-lto', dest='force_lto', action='store_true',
155               help='Use Link-Time Optimization instead of partial linking' +
156                    ' when the compiler doesn\'t support using them together.')
157AddLocalOption('--update-ref', dest='update_ref', action='store_true',
158               help='Update test reference outputs')
159AddLocalOption('--verbose', dest='verbose', action='store_true',
160               help='Print full tool command lines')
161AddLocalOption('--without-python', dest='without_python',
162               action='store_true',
163               help='Build without Python configuration support')
164AddLocalOption('--without-tcmalloc', dest='without_tcmalloc',
165               action='store_true',
166               help='Disable linking against tcmalloc')
167AddLocalOption('--with-ubsan', dest='with_ubsan', action='store_true',
168               help='Build with Undefined Behavior Sanitizer if available')
169AddLocalOption('--with-asan', dest='with_asan', action='store_true',
170               help='Build with Address Sanitizer if available')
171
172if GetOption('no_lto') and GetOption('force_lto'):
173    print('--no-lto and --force-lto are mutually exclusive')
174    Exit(1)
175
176########################################################################
177#
178# Set up the main build environment.
179#
180########################################################################
181
182main = Environment()
183
184from gem5_scons import Transform
185from gem5_scons.util import get_termcap
186termcap = get_termcap()
187
188main_dict_keys = main.Dictionary().keys()
189
190# Check that we have a C/C++ compiler
191if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
192    print("No C++ compiler installed (package g++ on Ubuntu and RedHat)")
193    Exit(1)
194
195###################################################
196#
197# Figure out which configurations to set up based on the path(s) of
198# the target(s).
199#
200###################################################
201
202# Find default configuration & binary.
203Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))
204
205# helper function: find last occurrence of element in list
206def rfind(l, elt, offs = -1):
207    for i in range(len(l)+offs, 0, -1):
208        if l[i] == elt:
209            return i
210    raise ValueError, "element not found"
211
212# Take a list of paths (or SCons Nodes) and return a list with all
213# paths made absolute and ~-expanded.  Paths will be interpreted
214# relative to the launch directory unless a different root is provided
215def makePathListAbsolute(path_list, root=GetLaunchDir()):
216    return [abspath(joinpath(root, expanduser(str(p))))
217            for p in path_list]
218
219def find_first_prog(prog_names):
220    """Find the absolute path to the first existing binary in prog_names"""
221
222    if not isinstance(prog_names, (list, tuple)):
223        prog_names = [ prog_names ]
224
225    for p in prog_names:
226        p = main.WhereIs(p)
227        if p is not None:
228            return p
229
230    return None
231
232# Each target must have 'build' in the interior of the path; the
233# directory below this will determine the build parameters.  For
234# example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
235# recognize that ALPHA_SE specifies the configuration because it
236# follow 'build' in the build path.
237
238# The funky assignment to "[:]" is needed to replace the list contents
239# in place rather than reassign the symbol to a new list, which
240# doesn't work (obviously!).
241BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
242
243# Generate a list of the unique build roots and configs that the
244# collected targets reference.
245variant_paths = []
246build_root = None
247for t in BUILD_TARGETS:
248    path_dirs = t.split('/')
249    try:
250        build_top = rfind(path_dirs, 'build', -2)
251    except:
252        print("Error: no non-leaf 'build' dir found on target path", t)
253        Exit(1)
254    this_build_root = joinpath('/',*path_dirs[:build_top+1])
255    if not build_root:
256        build_root = this_build_root
257    else:
258        if this_build_root != build_root:
259            print("Error: build targets not under same build root\n"
260                  "  %s\n  %s" % (build_root, this_build_root))
261            Exit(1)
262    variant_path = joinpath('/',*path_dirs[:build_top+2])
263    if variant_path not in variant_paths:
264        variant_paths.append(variant_path)
265
266# Make sure build_root exists (might not if this is the first build there)
267if not isdir(build_root):
268    mkdir(build_root)
269main['BUILDROOT'] = build_root
270
271Export('main')
272
273main.SConsignFile(joinpath(build_root, "sconsign"))
274
275# Default duplicate option is to use hard links, but this messes up
276# when you use emacs to edit a file in the target dir, as emacs moves
277# file to file~ then copies to file, breaking the link.  Symbolic
278# (soft) links work better.
279main.SetOption('duplicate', 'soft-copy')
280
281#
282# Set up global sticky variables... these are common to an entire build
283# tree (not specific to a particular build like ALPHA_SE)
284#
285
286global_vars_file = joinpath(build_root, 'variables.global')
287
288global_vars = Variables(global_vars_file, args=ARGUMENTS)
289
290global_vars.AddVariables(
291    ('CC', 'C compiler', environ.get('CC', main['CC'])),
292    ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
293    ('CCFLAGS_EXTRA', 'Extra C and C++ compiler flags', ''),
294    ('LDFLAGS_EXTRA', 'Extra linker flags', ''),
295    ('PYTHON_CONFIG', 'Python config binary to use',
296     [ 'python2.7-config', 'python-config' ]),
297    ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
298    ('BATCH', 'Use batch pool for build and tests', False),
299    ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
300    ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
301    ('EXTRAS', 'Add extra directories to the compilation', '')
302    )
303
304# Update main environment with values from ARGUMENTS & global_vars_file
305global_vars.Update(main)
306help_texts["global_vars"] += global_vars.GenerateHelpText(main)
307
308# Save sticky variable settings back to current variables file
309global_vars.Save(global_vars_file, main)
310
311# Parse EXTRAS variable to build list of all directories where we're
312# look for sources etc.  This list is exported as extras_dir_list.
313base_dir = main.srcdir.abspath
314if main['EXTRAS']:
315    extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
316else:
317    extras_dir_list = []
318
319Export('base_dir')
320Export('extras_dir_list')
321
322# the ext directory should be on the #includes path
323main.Append(CPPPATH=[Dir('ext')])
324
325# Add shared top-level headers
326main.Prepend(CPPPATH=Dir('include'))
327
328if GetOption('verbose'):
329    def MakeAction(action, string, *args, **kwargs):
330        return Action(action, *args, **kwargs)
331else:
332    MakeAction = Action
333    main['CCCOMSTR']        = Transform("CC")
334    main['CXXCOMSTR']       = Transform("CXX")
335    main['ASCOMSTR']        = Transform("AS")
336    main['ARCOMSTR']        = Transform("AR", 0)
337    main['LINKCOMSTR']      = Transform("LINK", 0)
338    main['SHLINKCOMSTR']    = Transform("SHLINK", 0)
339    main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
340    main['M4COMSTR']        = Transform("M4")
341    main['SHCCCOMSTR']      = Transform("SHCC")
342    main['SHCXXCOMSTR']     = Transform("SHCXX")
343Export('MakeAction')
344
345# Initialize the Link-Time Optimization (LTO) flags
346main['LTO_CCFLAGS'] = []
347main['LTO_LDFLAGS'] = []
348
349# According to the readme, tcmalloc works best if the compiler doesn't
350# assume that we're using the builtin malloc and friends. These flags
351# are compiler-specific, so we need to set them after we detect which
352# compiler we're using.
353main['TCMALLOC_CCFLAGS'] = []
354
355CXX_version = readCommand([main['CXX'],'--version'], exception=False)
356CXX_V = readCommand([main['CXX'],'-V'], exception=False)
357
358main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
359main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
360if main['GCC'] + main['CLANG'] > 1:
361    print('Error: How can we have two at the same time?')
362    Exit(1)
363
364# Set up default C++ compiler flags
365if main['GCC'] or main['CLANG']:
366    # As gcc and clang share many flags, do the common parts here
367    main.Append(CCFLAGS=['-pipe'])
368    main.Append(CCFLAGS=['-fno-strict-aliasing'])
369    # Enable -Wall and -Wextra and then disable the few warnings that
370    # we consistently violate
371    main.Append(CCFLAGS=['-Wall', '-Wundef', '-Wextra',
372                         '-Wno-sign-compare', '-Wno-unused-parameter'])
373    # We always compile using C++11
374    main.Append(CXXFLAGS=['-std=c++11'])
375    if sys.platform.startswith('freebsd'):
376        main.Append(CCFLAGS=['-I/usr/local/include'])
377        main.Append(CXXFLAGS=['-I/usr/local/include'])
378
379    main['FILTER_PSHLINKFLAGS'] = lambda x: str(x).replace(' -shared', '')
380    main['PSHLINKFLAGS'] = main.subst('${FILTER_PSHLINKFLAGS(SHLINKFLAGS)}')
381    if GetOption('gold_linker'):
382        main.Append(LINKFLAGS='-fuse-ld=gold')
383    main['PLINKFLAGS'] = main.subst('${LINKFLAGS}')
384    shared_partial_flags = ['-r', '-nostdlib']
385    main.Append(PSHLINKFLAGS=shared_partial_flags)
386    main.Append(PLINKFLAGS=shared_partial_flags)
387
388    # Treat warnings as errors but white list some warnings that we
389    # want to allow (e.g., deprecation warnings).
390    main.Append(CCFLAGS=['-Werror',
391                         '-Wno-error=deprecated-declarations',
392                         '-Wno-error=deprecated',
393                        ])
394else:
395    print(termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal, end=' ')
396    print("Don't know what compiler options to use for your compiler.")
397    print(termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX'])
398    print(termcap.Yellow + '       version:' + termcap.Normal, end = ' ')
399    if not CXX_version:
400        print(termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +
401              termcap.Normal)
402    else:
403        print(CXX_version.replace('\n', '<nl>'))
404    print("       If you're trying to use a compiler other than GCC")
405    print("       or clang, there appears to be something wrong with your")
406    print("       environment.")
407    print("       ")
408    print("       If you are trying to use a compiler other than those listed")
409    print("       above you will need to ease fix SConstruct and ")
410    print("       src/SConscript to support that compiler.")
411    Exit(1)
412
413if main['GCC']:
414    # Check for a supported version of gcc. >= 4.8 is chosen for its
415    # level of c++11 support. See
416    # http://gcc.gnu.org/projects/cxx0x.html for details.
417    gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
418    if compareVersions(gcc_version, "4.8") < 0:
419        print('Error: gcc version 4.8 or newer required.')
420        print('       Installed version: ', gcc_version)
421        Exit(1)
422
423    main['GCC_VERSION'] = gcc_version
424
425    if compareVersions(gcc_version, '4.9') >= 0:
426        # Incremental linking with LTO is currently broken in gcc versions
427        # 4.9 and above. A version where everything works completely hasn't
428        # yet been identified.
429        #
430        # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548
431        main['BROKEN_INCREMENTAL_LTO'] = True
432    if compareVersions(gcc_version, '6.0') >= 0:
433        # gcc versions 6.0 and greater accept an -flinker-output flag which
434        # selects what type of output the linker should generate. This is
435        # necessary for incremental lto to work, but is also broken in
436        # current versions of gcc. It may not be necessary in future
437        # versions. We add it here since it might be, and as a reminder that
438        # it exists. It's excluded if lto is being forced.
439        #
440        # https://gcc.gnu.org/gcc-6/changes.html
441        # https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03161.html
442        # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69866
443        if not GetOption('force_lto'):
444            main.Append(PSHLINKFLAGS='-flinker-output=rel')
445            main.Append(PLINKFLAGS='-flinker-output=rel')
446
447    # Make sure we warn if the user has requested to compile with the
448    # Undefined Benahvior Sanitizer and this version of gcc does not
449    # support it.
450    if GetOption('with_ubsan') and \
451            compareVersions(gcc_version, '4.9') < 0:
452        print(termcap.Yellow + termcap.Bold +
453            'Warning: UBSan is only supported using gcc 4.9 and later.' +
454            termcap.Normal)
455
456    disable_lto = GetOption('no_lto')
457    if not disable_lto and main.get('BROKEN_INCREMENTAL_LTO', False) and \
458            not GetOption('force_lto'):
459        print(termcap.Yellow + termcap.Bold +
460            'Warning: Your compiler doesn\'t support incremental linking' +
461            ' and lto at the same time, so lto is being disabled. To force' +
462            ' lto on anyway, use the --force-lto option. That will disable' +
463            ' partial linking.' +
464            termcap.Normal)
465        disable_lto = True
466
467    # Add the appropriate Link-Time Optimization (LTO) flags
468    # unless LTO is explicitly turned off. Note that these flags
469    # are only used by the fast target.
470    if not disable_lto:
471        # Pass the LTO flag when compiling to produce GIMPLE
472        # output, we merely create the flags here and only append
473        # them later
474        main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
475
476        # Use the same amount of jobs for LTO as we are running
477        # scons with
478        main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
479
480    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
481                                  '-fno-builtin-realloc', '-fno-builtin-free'])
482
483    # The address sanitizer is available for gcc >= 4.8
484    if GetOption('with_asan'):
485        if GetOption('with_ubsan') and \
486                compareVersions(main['GCC_VERSION'], '4.9') >= 0:
487            main.Append(CCFLAGS=['-fsanitize=address,undefined',
488                                 '-fno-omit-frame-pointer'],
489                        LINKFLAGS='-fsanitize=address,undefined')
490        else:
491            main.Append(CCFLAGS=['-fsanitize=address',
492                                 '-fno-omit-frame-pointer'],
493                        LINKFLAGS='-fsanitize=address')
494    # Only gcc >= 4.9 supports UBSan, so check both the version
495    # and the command-line option before adding the compiler and
496    # linker flags.
497    elif GetOption('with_ubsan') and \
498            compareVersions(main['GCC_VERSION'], '4.9') >= 0:
499        main.Append(CCFLAGS='-fsanitize=undefined')
500        main.Append(LINKFLAGS='-fsanitize=undefined')
501
502elif main['CLANG']:
503    # Check for a supported version of clang, >= 3.1 is needed to
504    # support similar features as gcc 4.8. See
505    # http://clang.llvm.org/cxx_status.html for details
506    clang_version_re = re.compile(".* version (\d+\.\d+)")
507    clang_version_match = clang_version_re.search(CXX_version)
508    if (clang_version_match):
509        clang_version = clang_version_match.groups()[0]
510        if compareVersions(clang_version, "3.1") < 0:
511            print('Error: clang version 3.1 or newer required.')
512            print('       Installed version:', clang_version)
513            Exit(1)
514    else:
515        print('Error: Unable to determine clang version.')
516        Exit(1)
517
518    # clang has a few additional warnings that we disable, extraneous
519    # parantheses are allowed due to Ruby's printing of the AST,
520    # finally self assignments are allowed as the generated CPU code
521    # is relying on this
522    main.Append(CCFLAGS=['-Wno-parentheses',
523                         '-Wno-self-assign',
524                         # Some versions of libstdc++ (4.8?) seem to
525                         # use struct hash and class hash
526                         # interchangeably.
527                         '-Wno-mismatched-tags',
528                         ])
529
530    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
531
532    # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
533    # opposed to libstdc++, as the later is dated.
534    if sys.platform == "darwin":
535        main.Append(CXXFLAGS=['-stdlib=libc++'])
536        main.Append(LIBS=['c++'])
537
538    # On FreeBSD we need libthr.
539    if sys.platform.startswith('freebsd'):
540        main.Append(LIBS=['thr'])
541
542    # We require clang >= 3.1, so there is no need to check any
543    # versions here.
544    if GetOption('with_ubsan'):
545        if GetOption('with_asan'):
546            main.Append(CCFLAGS=['-fsanitize=address,undefined',
547                                 '-fno-omit-frame-pointer'],
548                       LINKFLAGS='-fsanitize=address,undefined')
549        else:
550            main.Append(CCFLAGS='-fsanitize=undefined',
551                        LINKFLAGS='-fsanitize=undefined')
552
553    elif GetOption('with_asan'):
554        main.Append(CCFLAGS=['-fsanitize=address',
555                             '-fno-omit-frame-pointer'],
556                   LINKFLAGS='-fsanitize=address')
557
558else:
559    print(termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal, end=' ')
560    print("Don't know what compiler options to use for your compiler.")
561    print(termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX'])
562    print(termcap.Yellow + '       version:' + termcap.Normal, end=' ')
563    if not CXX_version:
564        print(termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +
565              termcap.Normal)
566    else:
567        print(CXX_version.replace('\n', '<nl>'))
568    print("       If you're trying to use a compiler other than GCC")
569    print("       or clang, there appears to be something wrong with your")
570    print("       environment.")
571    print("       ")
572    print("       If you are trying to use a compiler other than those listed")
573    print("       above you will need to ease fix SConstruct and ")
574    print("       src/SConscript to support that compiler.")
575    Exit(1)
576
577# Set up common yacc/bison flags (needed for Ruby)
578main['YACCFLAGS'] = '-d'
579main['YACCHXXFILESUFFIX'] = '.hh'
580
581# Do this after we save setting back, or else we'll tack on an
582# extra 'qdo' every time we run scons.
583if main['BATCH']:
584    main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
585    main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
586    main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
587    main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
588    main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
589
590if sys.platform == 'cygwin':
591    # cygwin has some header file issues...
592    main.Append(CCFLAGS=["-Wno-uninitialized"])
593
594
595have_pkg_config = readCommand(['pkg-config', '--version'], exception='')
596
597# Check for the protobuf compiler
598protoc_version = readCommand([main['PROTOC'], '--version'],
599                             exception='').split()
600
601# First two words should be "libprotoc x.y.z"
602if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
603    print(termcap.Yellow + termcap.Bold +
604        'Warning: Protocol buffer compiler (protoc) not found.\n' +
605        '         Please install protobuf-compiler for tracing support.' +
606        termcap.Normal)
607    main['PROTOC'] = False
608else:
609    # Based on the availability of the compress stream wrappers,
610    # require 2.1.0
611    min_protoc_version = '2.1.0'
612    if compareVersions(protoc_version[1], min_protoc_version) < 0:
613        print(termcap.Yellow + termcap.Bold +
614            'Warning: protoc version', min_protoc_version,
615            'or newer required.\n' +
616            '         Installed version:', protoc_version[1],
617            termcap.Normal)
618        main['PROTOC'] = False
619    else:
620        # Attempt to determine the appropriate include path and
621        # library path using pkg-config, that means we also need to
622        # check for pkg-config. Note that it is possible to use
623        # protobuf without the involvement of pkg-config. Later on we
624        # check go a library config check and at that point the test
625        # will fail if libprotobuf cannot be found.
626        if have_pkg_config:
627            try:
628                # Attempt to establish what linking flags to add for protobuf
629                # using pkg-config
630                main.ParseConfig('pkg-config --cflags --libs-only-L protobuf')
631            except:
632                print(termcap.Yellow + termcap.Bold +
633                    'Warning: pkg-config could not get protobuf flags.' +
634                    termcap.Normal)
635
636
637# Check for 'timeout' from GNU coreutils. If present, regressions will
638# be run with a time limit. We require version 8.13 since we rely on
639# support for the '--foreground' option.
640if sys.platform.startswith('freebsd'):
641    timeout_lines = readCommand(['gtimeout', '--version'],
642                                exception='').splitlines()
643else:
644    timeout_lines = readCommand(['timeout', '--version'],
645                                exception='').splitlines()
646# Get the first line and tokenize it
647timeout_version = timeout_lines[0].split() if timeout_lines else []
648main['TIMEOUT'] =  timeout_version and \
649    compareVersions(timeout_version[-1], '8.13') >= 0
650
651# Add a custom Check function to test for structure members.
652def CheckMember(context, include, decl, member, include_quotes="<>"):
653    context.Message("Checking for member %s in %s..." %
654                    (member, decl))
655    text = """
656#include %(header)s
657int main(){
658  %(decl)s test;
659  (void)test.%(member)s;
660  return 0;
661};
662""" % { "header" : include_quotes[0] + include + include_quotes[1],
663        "decl" : decl,
664        "member" : member,
665        }
666
667    ret = context.TryCompile(text, extension=".cc")
668    context.Result(ret)
669    return ret
670
671# Platform-specific configuration.  Note again that we assume that all
672# builds under a given build root run on the same host platform.
673conf = Configure(main,
674                 conf_dir = joinpath(build_root, '.scons_config'),
675                 log_file = joinpath(build_root, 'scons_config.log'),
676                 custom_tests = {
677        'CheckMember' : CheckMember,
678        })
679
680# Check if we should compile a 64 bit binary on Mac OS X/Darwin
681try:
682    import platform
683    uname = platform.uname()
684    if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
685        if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
686            main.Append(CCFLAGS=['-arch', 'x86_64'])
687            main.Append(CFLAGS=['-arch', 'x86_64'])
688            main.Append(LINKFLAGS=['-arch', 'x86_64'])
689            main.Append(ASFLAGS=['-arch', 'x86_64'])
690except:
691    pass
692
693# Recent versions of scons substitute a "Null" object for Configure()
694# when configuration isn't necessary, e.g., if the "--help" option is
695# present.  Unfortuantely this Null object always returns false,
696# breaking all our configuration checks.  We replace it with our own
697# more optimistic null object that returns True instead.
698if not conf:
699    def NullCheck(*args, **kwargs):
700        return True
701
702    class NullConf:
703        def __init__(self, env):
704            self.env = env
705        def Finish(self):
706            return self.env
707        def __getattr__(self, mname):
708            return NullCheck
709
710    conf = NullConf(main)
711
712# Cache build files in the supplied directory.
713if main['M5_BUILD_CACHE']:
714    print('Using build cache located at', main['M5_BUILD_CACHE'])
715    CacheDir(main['M5_BUILD_CACHE'])
716
717main['USE_PYTHON'] = not GetOption('without_python')
718if main['USE_PYTHON']:
719    # Find Python include and library directories for embedding the
720    # interpreter. We rely on python-config to resolve the appropriate
721    # includes and linker flags. ParseConfig does not seem to understand
722    # the more exotic linker flags such as -Xlinker and -export-dynamic so
723    # we add them explicitly below. If you want to link in an alternate
724    # version of python, see above for instructions on how to invoke
725    # scons with the appropriate PATH set.
726
727    python_config = find_first_prog(main['PYTHON_CONFIG'])
728    if python_config is None:
729        print("Error: can't find a suitable python-config, tried %s" % \
730              main['PYTHON_CONFIG'])
731        Exit(1)
732
733    print("Info: Using Python config: %s" % (python_config, ))
734    py_includes = readCommand([python_config, '--includes'],
735                              exception='').split()
736    py_includes = filter(lambda s: match(r'.*\/include\/.*',s), py_includes)
737    # Strip the -I from the include folders before adding them to the
738    # CPPPATH
739    py_includes = map(lambda s: s[2:] if s.startswith('-I') else s, py_includes)
740    main.Append(CPPPATH=py_includes)
741
742    # Read the linker flags and split them into libraries and other link
743    # flags. The libraries are added later through the call the CheckLib.
744    py_ld_flags = readCommand([python_config, '--ldflags'],
745        exception='').split()
746    py_libs = []
747    for lib in py_ld_flags:
748         if not lib.startswith('-l'):
749             main.Append(LINKFLAGS=[lib])
750         else:
751             lib = lib[2:]
752             if lib not in py_libs:
753                 py_libs.append(lib)
754
755    # verify that this stuff works
756    if not conf.CheckHeader('Python.h', '<>'):
757        print("Error: Check failed for Python.h header in", py_includes)
758        print("Two possible reasons:")
759        print("1. Python headers are not installed (You can install the "
760              "package python-dev on Ubuntu and RedHat)")
761        print("2. SCons is using a wrong C compiler. This can happen if "
762              "CC has the wrong value.")
763        print("CC = %s" % main['CC'])
764        Exit(1)
765
766    for lib in py_libs:
767        if not conf.CheckLib(lib):
768            print("Error: can't find library %s required by python" % lib)
769            Exit(1)
770
771# On Solaris you need to use libsocket for socket ops
772if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
773   if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
774       print("Can't find library with socket calls (e.g. accept())")
775       Exit(1)
776
777# Check for zlib.  If the check passes, libz will be automatically
778# added to the LIBS environment variable.
779if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
780    print('Error: did not find needed zlib compression library '
781          'and/or zlib.h header file.')
782    print('       Please install zlib and try again.')
783    Exit(1)
784
785# If we have the protobuf compiler, also make sure we have the
786# development libraries. If the check passes, libprotobuf will be
787# automatically added to the LIBS environment variable. After
788# this, we can use the HAVE_PROTOBUF flag to determine if we have
789# got both protoc and libprotobuf available.
790main['HAVE_PROTOBUF'] = main['PROTOC'] and \
791    conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
792                            'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
793
794# Valgrind gets much less confused if you tell it when you're using
795# alternative stacks.
796main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
797
798# If we have the compiler but not the library, print another warning.
799if main['PROTOC'] and not main['HAVE_PROTOBUF']:
800    print(termcap.Yellow + termcap.Bold +
801        'Warning: did not find protocol buffer library and/or headers.\n' +
802    '       Please install libprotobuf-dev for tracing support.' +
803    termcap.Normal)
804
805# Check for librt.
806have_posix_clock = \
807    conf.CheckLibWithHeader(None, 'time.h', 'C',
808                            'clock_nanosleep(0,0,NULL,NULL);') or \
809    conf.CheckLibWithHeader('rt', 'time.h', 'C',
810                            'clock_nanosleep(0,0,NULL,NULL);')
811
812have_posix_timers = \
813    conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
814                            'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
815
816if not GetOption('without_tcmalloc'):
817    if conf.CheckLib('tcmalloc'):
818        main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
819    elif conf.CheckLib('tcmalloc_minimal'):
820        main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
821    else:
822        print(termcap.Yellow + termcap.Bold +
823              "You can get a 12% performance improvement by "
824              "installing tcmalloc (libgoogle-perftools-dev package "
825              "on Ubuntu or RedHat)." + termcap.Normal)
826
827
828# Detect back trace implementations. The last implementation in the
829# list will be used by default.
830backtrace_impls = [ "none" ]
831
832backtrace_checker = 'char temp;' + \
833    ' backtrace_symbols_fd((void*)&temp, 0, 0);'
834if conf.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker):
835    backtrace_impls.append("glibc")
836elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
837                             backtrace_checker):
838    # NetBSD and FreeBSD need libexecinfo.
839    backtrace_impls.append("glibc")
840    main.Append(LIBS=['execinfo'])
841
842if backtrace_impls[-1] == "none":
843    default_backtrace_impl = "none"
844    print(termcap.Yellow + termcap.Bold +
845        "No suitable back trace implementation found." +
846        termcap.Normal)
847
848if not have_posix_clock:
849    print("Can't find library for POSIX clocks.")
850
851# Check for <fenv.h> (C99 FP environment control)
852have_fenv = conf.CheckHeader('fenv.h', '<>')
853if not have_fenv:
854    print("Warning: Header file <fenv.h> not found.")
855    print("         This host has no IEEE FP rounding mode control.")
856
857# Check for <png.h> (libpng library needed if wanting to dump
858# frame buffer image in png format)
859have_png = conf.CheckHeader('png.h', '<>')
860if not have_png:
861    print("Warning: Header file <png.h> not found.")
862    print("         This host has no libpng library.")
863    print("         Disabling support for PNG framebuffers.")
864
865# Check if we should enable KVM-based hardware virtualization. The API
866# we rely on exists since version 2.6.36 of the kernel, but somehow
867# the KVM_API_VERSION does not reflect the change. We test for one of
868# the types as a fall back.
869have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
870if not have_kvm:
871    print("Info: Compatible header file <linux/kvm.h> not found, "
872          "disabling KVM support.")
873
874# Check if the TUN/TAP driver is available.
875have_tuntap = conf.CheckHeader('linux/if_tun.h', '<>')
876if not have_tuntap:
877    print("Info: Compatible header file <linux/if_tun.h> not found.")
878
879# x86 needs support for xsave. We test for the structure here since we
880# won't be able to run new tests by the time we know which ISA we're
881# targeting.
882have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
883                                    '#include <linux/kvm.h>') != 0
884
885# Check if the requested target ISA is compatible with the host
886def is_isa_kvm_compatible(isa):
887    try:
888        import platform
889        host_isa = platform.machine()
890    except:
891        print("Warning: Failed to determine host ISA.")
892        return False
893
894    if not have_posix_timers:
895        print("Warning: Can not enable KVM, host seems to lack support "
896              "for POSIX timers")
897        return False
898
899    if isa == "arm":
900        return host_isa in ( "armv7l", "aarch64" )
901    elif isa == "x86":
902        if host_isa != "x86_64":
903            return False
904
905        if not have_kvm_xsave:
906            print("KVM on x86 requires xsave support in kernel headers.")
907            return False
908
909        return True
910    else:
911        return False
912
913
914# Check if the exclude_host attribute is available. We want this to
915# get accurate instruction counts in KVM.
916main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
917    'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
918
919def check_hdf5():
920    return \
921        conf.CheckLibWithHeader('hdf5', 'hdf5.h', 'C',
922                                'H5Fcreate("", 0, 0, 0);') and \
923        conf.CheckLibWithHeader('hdf5_cpp', 'H5Cpp.h', 'C++',
924                                'H5::H5File("", 0);')
925
926def check_hdf5_pkg(name):
927    print("Checking for %s using pkg-config..." % name, end="")
928    if not have_pkg_config:
929        print(" pkg-config not found")
930        return False
931
932    try:
933        main.ParseConfig('pkg-config --cflags-only-I --libs-only-L %s' % name)
934        print(" yes")
935        return True
936    except:
937        print(" no")
938        return False
939
940# Check if there is a pkg-config configuration for hdf5. If we find
941# it, setup the environment to enable linking and header inclusion. We
942# don't actually try to include any headers or link with hdf5 at this
943# stage.
944if not check_hdf5_pkg('hdf5-serial'):
945    check_hdf5_pkg('hdf5')
946
947# Check if the HDF5 libraries can be found. This check respects the
948# include path and library path provided by pkg-config. We perform
949# this check even if there isn't a pkg-config configuration for hdf5
950# since some installations don't use pkg-config.
951have_hdf5 = check_hdf5()
952if not have_hdf5:
953    print("Warning: Couldn't find any HDF5 C++ libraries. Disabling")
954    print("         HDF5 support.")
955
956######################################################################
957#
958# Finish the configuration
959#
960main = conf.Finish()
961
962######################################################################
963#
964# Collect all non-global variables
965#
966
967# Define the universe of supported ISAs
968all_isa_list = [ ]
969all_gpu_isa_list = [ ]
970Export('all_isa_list')
971Export('all_gpu_isa_list')
972
973class CpuModel(object):
974    '''The CpuModel class encapsulates everything the ISA parser needs to
975    know about a particular CPU model.'''
976
977    # Dict of available CPU model objects.  Accessible as CpuModel.dict.
978    dict = {}
979
980    # Constructor.  Automatically adds models to CpuModel.dict.
981    def __init__(self, name, default=False):
982        self.name = name           # name of model
983
984        # This cpu is enabled by default
985        self.default = default
986
987        # Add self to dict
988        if name in CpuModel.dict:
989            raise AttributeError, "CpuModel '%s' already registered" % name
990        CpuModel.dict[name] = self
991
992Export('CpuModel')
993
994# Sticky variables get saved in the variables file so they persist from
995# one invocation to the next (unless overridden, in which case the new
996# value becomes sticky).
997sticky_vars = Variables(args=ARGUMENTS)
998Export('sticky_vars')
999
1000# Sticky variables that should be exported
1001export_vars = []
1002Export('export_vars')
1003
1004# For Ruby
1005all_protocols = []
1006Export('all_protocols')
1007protocol_dirs = []
1008Export('protocol_dirs')
1009slicc_includes = []
1010Export('slicc_includes')
1011
1012# Walk the tree and execute all SConsopts scripts that wil add to the
1013# above variables
1014if GetOption('verbose'):
1015    print("Reading SConsopts")
1016for bdir in [ base_dir ] + extras_dir_list:
1017    if not isdir(bdir):
1018        print("Error: directory '%s' does not exist" % bdir)
1019        Exit(1)
1020    for root, dirs, files in os.walk(bdir):
1021        if 'SConsopts' in files:
1022            if GetOption('verbose'):
1023                print("Reading", joinpath(root, 'SConsopts'))
1024            SConscript(joinpath(root, 'SConsopts'))
1025
1026all_isa_list.sort()
1027all_gpu_isa_list.sort()
1028
1029sticky_vars.AddVariables(
1030    EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
1031    EnumVariable('TARGET_GPU_ISA', 'Target GPU ISA', 'hsail', all_gpu_isa_list),
1032    ListVariable('CPU_MODELS', 'CPU models',
1033                 sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
1034                 sorted(CpuModel.dict.keys())),
1035    BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
1036                 False),
1037    BoolVariable('SS_COMPATIBLE_FP',
1038                 'Make floating-point results compatible with SimpleScalar',
1039                 False),
1040    BoolVariable('USE_SSE2',
1041                 'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
1042                 False),
1043    BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
1044    BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
1045    BoolVariable('USE_PNG',  'Enable support for PNG images', have_png),
1046    BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability',
1047                 False),
1048    BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models',
1049                 have_kvm),
1050    BoolVariable('USE_TUNTAP',
1051                 'Enable using a tap device to bridge to the host network',
1052                 have_tuntap),
1053    BoolVariable('BUILD_GPU', 'Build the compute-GPU model', False),
1054    EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1055                  all_protocols),
1056    EnumVariable('BACKTRACE_IMPL', 'Post-mortem dump implementation',
1057                 backtrace_impls[-1], backtrace_impls),
1058    ('NUMBER_BITS_PER_SET', 'Max elements in set (default 64)',
1059                 64),
1060    BoolVariable('USE_HDF5', 'Enable the HDF5 support', have_hdf5),
1061    )
1062
1063# These variables get exported to #defines in config/*.hh (see src/SConscript).
1064export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'TARGET_GPU_ISA',
1065                'CP_ANNOTATE', 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP',
1066                'PROTOCOL', 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
1067                'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG',
1068                'NUMBER_BITS_PER_SET', 'USE_HDF5']
1069
1070###################################################
1071#
1072# Define a SCons builder for configuration flag headers.
1073#
1074###################################################
1075
1076# This function generates a config header file that #defines the
1077# variable symbol to the current variable setting (0 or 1).  The source
1078# operands are the name of the variable and a Value node containing the
1079# value of the variable.
1080def build_config_file(target, source, env):
1081    (variable, value) = [s.get_contents() for s in source]
1082    f = file(str(target[0]), 'w')
1083    print('#define', variable, value, file=f)
1084    f.close()
1085    return None
1086
1087# Combine the two functions into a scons Action object.
1088config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1089
1090# The emitter munges the source & target node lists to reflect what
1091# we're really doing.
1092def config_emitter(target, source, env):
1093    # extract variable name from Builder arg
1094    variable = str(target[0])
1095    # True target is config header file
1096    target = joinpath('config', variable.lower() + '.hh')
1097    val = env[variable]
1098    if isinstance(val, bool):
1099        # Force value to 0/1
1100        val = int(val)
1101    elif isinstance(val, str):
1102        val = '"' + val + '"'
1103
1104    # Sources are variable name & value (packaged in SCons Value nodes)
1105    return ([target], [Value(variable), Value(val)])
1106
1107config_builder = Builder(emitter = config_emitter, action = config_action)
1108
1109main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1110
1111###################################################
1112#
1113# Builders for static and shared partially linked object files.
1114#
1115###################################################
1116
1117partial_static_builder = Builder(action=SCons.Defaults.LinkAction,
1118                                 src_suffix='$OBJSUFFIX',
1119                                 src_builder=['StaticObject', 'Object'],
1120                                 LINKFLAGS='$PLINKFLAGS',
1121                                 LIBS='')
1122
1123def partial_shared_emitter(target, source, env):
1124    for tgt in target:
1125        tgt.attributes.shared = 1
1126    return (target, source)
1127partial_shared_builder = Builder(action=SCons.Defaults.ShLinkAction,
1128                                 emitter=partial_shared_emitter,
1129                                 src_suffix='$SHOBJSUFFIX',
1130                                 src_builder='SharedObject',
1131                                 SHLINKFLAGS='$PSHLINKFLAGS',
1132                                 LIBS='')
1133
1134main.Append(BUILDERS = { 'PartialShared' : partial_shared_builder,
1135                         'PartialStatic' : partial_static_builder })
1136
1137def add_local_rpath(env, *targets):
1138    '''Set up an RPATH for a library which lives in the build directory.
1139
1140    The construction environment variable BIN_RPATH_PREFIX should be set to
1141    the relative path of the build directory starting from the location of the
1142    binary.'''
1143    for target in targets:
1144        target = env.Entry(target)
1145        if not isinstance(target, SCons.Node.FS.Dir):
1146            target = target.dir
1147        relpath = os.path.relpath(target.abspath, env['BUILDDIR'])
1148        components = [
1149            '\\$$ORIGIN',
1150            '${BIN_RPATH_PREFIX}',
1151            relpath
1152        ]
1153        env.Append(RPATH=[env.Literal(os.path.join(*components))])
1154
1155if sys.platform != "darwin":
1156    main.Append(LINKFLAGS=Split('-z origin'))
1157
1158main.AddMethod(add_local_rpath, 'AddLocalRPATH')
1159
1160# builds in ext are shared across all configs in the build root.
1161ext_dir = abspath(joinpath(str(main.root), 'ext'))
1162ext_build_dirs = []
1163for root, dirs, files in os.walk(ext_dir):
1164    if 'SConscript' in files:
1165        build_dir = os.path.relpath(root, ext_dir)
1166        ext_build_dirs.append(build_dir)
1167        main.SConscript(joinpath(root, 'SConscript'),
1168                        variant_dir=joinpath(build_root, build_dir))
1169
1170gdb_xml_dir = joinpath(ext_dir, 'gdb-xml')
1171Export('gdb_xml_dir')
1172
1173main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
1174
1175###################################################
1176#
1177# This builder and wrapper method are used to set up a directory with
1178# switching headers. Those are headers which are in a generic location and
1179# that include more specific headers from a directory chosen at build time
1180# based on the current build settings.
1181#
1182###################################################
1183
1184def build_switching_header(target, source, env):
1185    path = str(target[0])
1186    subdir = str(source[0])
1187    dp, fp = os.path.split(path)
1188    dp = os.path.relpath(os.path.realpath(dp),
1189                         os.path.realpath(env['BUILDDIR']))
1190    with open(path, 'w') as hdr:
1191        print('#include "%s/%s/%s"' % (dp, subdir, fp), file=hdr)
1192
1193switching_header_action = MakeAction(build_switching_header,
1194                                     Transform('GENERATE'))
1195
1196switching_header_builder = Builder(action=switching_header_action,
1197                                   source_factory=Value,
1198                                   single_source=True)
1199
1200main.Append(BUILDERS = { 'SwitchingHeader': switching_header_builder })
1201
1202def switching_headers(self, headers, source):
1203    for header in headers:
1204        self.SwitchingHeader(header, source)
1205
1206main.AddMethod(switching_headers, 'SwitchingHeaders')
1207
1208###################################################
1209#
1210# Define build environments for selected configurations.
1211#
1212###################################################
1213
1214for variant_path in variant_paths:
1215    if not GetOption('silent'):
1216        print("Building in", variant_path)
1217
1218    # Make a copy of the build-root environment to use for this config.
1219    env = main.Clone()
1220    env['BUILDDIR'] = variant_path
1221
1222    # variant_dir is the tail component of build path, and is used to
1223    # determine the build parameters (e.g., 'ALPHA_SE')
1224    (build_root, variant_dir) = splitpath(variant_path)
1225
1226    # Set env variables according to the build directory config.
1227    sticky_vars.files = []
1228    # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1229    # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1230    # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1231    current_vars_file = joinpath(build_root, 'variables', variant_dir)
1232    if isfile(current_vars_file):
1233        sticky_vars.files.append(current_vars_file)
1234        if not GetOption('silent'):
1235            print("Using saved variables file %s" % current_vars_file)
1236    elif variant_dir in ext_build_dirs:
1237        # Things in ext are built without a variant directory.
1238        continue
1239    else:
1240        # Build dir-specific variables file doesn't exist.
1241
1242        # Make sure the directory is there so we can create it later
1243        opt_dir = dirname(current_vars_file)
1244        if not isdir(opt_dir):
1245            mkdir(opt_dir)
1246
1247        # Get default build variables from source tree.  Variables are
1248        # normally determined by name of $VARIANT_DIR, but can be
1249        # overridden by '--default=' arg on command line.
1250        default = GetOption('default')
1251        opts_dir = joinpath(main.root.abspath, 'build_opts')
1252        if default:
1253            default_vars_files = [joinpath(build_root, 'variables', default),
1254                                  joinpath(opts_dir, default)]
1255        else:
1256            default_vars_files = [joinpath(opts_dir, variant_dir)]
1257        existing_files = filter(isfile, default_vars_files)
1258        if existing_files:
1259            default_vars_file = existing_files[0]
1260            sticky_vars.files.append(default_vars_file)
1261            print("Variables file %s not found,\n  using defaults in %s"
1262                  % (current_vars_file, default_vars_file))
1263        else:
1264            print("Error: cannot find variables file %s or "
1265                  "default file(s) %s"
1266                  % (current_vars_file, ' or '.join(default_vars_files)))
1267            Exit(1)
1268
1269    # Apply current variable settings to env
1270    sticky_vars.Update(env)
1271
1272    help_texts["local_vars"] += \
1273        "Build variables for %s:\n" % variant_dir \
1274                 + sticky_vars.GenerateHelpText(env)
1275
1276    # Process variable settings.
1277
1278    if not have_fenv and env['USE_FENV']:
1279        print("Warning: <fenv.h> not available; "
1280              "forcing USE_FENV to False in", variant_dir + ".")
1281        env['USE_FENV'] = False
1282
1283    if not env['USE_FENV']:
1284        print("Warning: No IEEE FP rounding mode control in",
1285              variant_dir + ".")
1286        print("         FP results may deviate slightly from other platforms.")
1287
1288    if not have_png and env['USE_PNG']:
1289        print("Warning: <png.h> not available; "
1290              "forcing USE_PNG to False in", variant_dir + ".")
1291        env['USE_PNG'] = False
1292
1293    if env['USE_PNG']:
1294        env.Append(LIBS=['png'])
1295
1296    if env['EFENCE']:
1297        env.Append(LIBS=['efence'])
1298
1299    if env['USE_KVM']:
1300        if not have_kvm:
1301            print("Warning: Can not enable KVM, host seems to "
1302                  "lack KVM support")
1303            env['USE_KVM'] = False
1304        elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1305            print("Info: KVM support disabled due to unsupported host and "
1306                  "target ISA combination")
1307            env['USE_KVM'] = False
1308
1309    if env['USE_TUNTAP']:
1310        if not have_tuntap:
1311            print("Warning: Can't connect EtherTap with a tap device.")
1312            env['USE_TUNTAP'] = False
1313
1314    if env['BUILD_GPU']:
1315        env.Append(CPPDEFINES=['BUILD_GPU'])
1316
1317    # Warn about missing optional functionality
1318    if env['USE_KVM']:
1319        if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1320            print("Warning: perf_event headers lack support for the "
1321                  "exclude_host attribute. KVM instruction counts will "
1322                  "be inaccurate.")
1323
1324    # Save sticky variable settings back to current variables file
1325    sticky_vars.Save(current_vars_file, env)
1326
1327    if env['USE_SSE2']:
1328        env.Append(CCFLAGS=['-msse2'])
1329
1330    env.Append(CCFLAGS='$CCFLAGS_EXTRA')
1331    env.Append(LINKFLAGS='$LDFLAGS_EXTRA')
1332
1333    # The src/SConscript file sets up the build rules in 'env' according
1334    # to the configured variables.  It returns a list of environments,
1335    # one for each variant build (debug, opt, etc.)
1336    SConscript('src/SConscript', variant_dir = variant_path, exports = 'env')
1337
1338# base help text
1339Help('''
1340Usage: scons [scons options] [build variables] [target(s)]
1341
1342Extra scons options:
1343%(options)s
1344
1345Global build variables:
1346%(global_vars)s
1347
1348%(local_vars)s
1349''' % help_texts)
1350