SConstruct revision 9591
1# -*- mode:python -*-
2
3# Copyright (c) 2011 Advanced Micro Devices, Inc.
4# Copyright (c) 2009 The Hewlett-Packard Development Company
5# Copyright (c) 2004-2005 The Regents of The University of Michigan
6# All rights reserved.
7#
8# Redistribution and use in source and binary forms, with or without
9# modification, are permitted provided that the following conditions are
10# met: redistributions of source code must retain the above copyright
11# notice, this list of conditions and the following disclaimer;
12# redistributions in binary form must reproduce the above copyright
13# notice, this list of conditions and the following disclaimer in the
14# documentation and/or other materials provided with the distribution;
15# neither the name of the copyright holders nor the names of its
16# contributors may be used to endorse or promote products derived from
17# this software without specific prior written permission.
18#
19# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30#
31# Authors: Steve Reinhardt
32#          Nathan Binkert
33
34###################################################
35#
36# SCons top-level build description (SConstruct) file.
37#
38# While in this directory ('gem5'), just type 'scons' to build the default
39# configuration (see below), or type 'scons build/<CONFIG>/<binary>'
40# to build some other configuration (e.g., 'build/ALPHA/gem5.opt' for
41# the optimized full-system version).
42#
43# You can build gem5 in a different directory as long as there is a
44# 'build/<CONFIG>' somewhere along the target path.  The build system
45# expects that all configs under the same build directory are being
46# built for the same host system.
47#
48# Examples:
49#
50#   The following two commands are equivalent.  The '-u' option tells
51#   scons to search up the directory tree for this SConstruct file.
52#   % cd <path-to-src>/gem5 ; scons build/ALPHA/gem5.debug
53#   % cd <path-to-src>/gem5/build/ALPHA; scons -u gem5.debug
54#
55#   The following two commands are equivalent and demonstrate building
56#   in a directory outside of the source tree.  The '-C' option tells
57#   scons to chdir to the specified directory to find this SConstruct
58#   file.
59#   % cd <path-to-src>/gem5 ; scons /local/foo/build/ALPHA/gem5.debug
60#   % cd /local/foo/build/ALPHA; scons -C <path-to-src>/gem5 gem5.debug
61#
62# You can use 'scons -H' to print scons options.  If you're in this
63# 'gem5' directory (or use -u or -C to tell scons where to find this
64# file), you can use 'scons -h' to print all the gem5-specific build
65# options as well.
66#
67###################################################
68
69# Check for recent-enough Python and SCons versions.
70try:
71    # Really old versions of scons only take two options for the
72    # function, so check once without the revision and once with the
73    # revision, the first instance will fail for stuff other than
74    # 0.98, and the second will fail for 0.98.0
75    EnsureSConsVersion(0, 98)
76    EnsureSConsVersion(0, 98, 1)
77except SystemExit, e:
78    print """
79For more details, see:
80    http://gem5.org/Dependencies
81"""
82    raise
83
84# We ensure the python version early because we have stuff that
85# requires python 2.4
86try:
87    EnsurePythonVersion(2, 4)
88except SystemExit, e:
89    print """
90You can use a non-default installation of the Python interpreter by
91either (1) rearranging your PATH so that scons finds the non-default
92'python' first or (2) explicitly invoking an alternative interpreter
93on the scons script.
94
95For more details, see:
96    http://gem5.org/wiki/index.php/Using_a_non-default_Python_installation
97"""
98    raise
99
100# Global Python includes
101import os
102import re
103import subprocess
104import sys
105
106from os import mkdir, environ
107from os.path import abspath, basename, dirname, expanduser, normpath
108from os.path import exists,  isdir, isfile
109from os.path import join as joinpath, split as splitpath
110
111# SCons includes
112import SCons
113import SCons.Node
114
115extra_python_paths = [
116    Dir('src/python').srcnode().abspath, # gem5 includes
117    Dir('ext/ply').srcnode().abspath, # ply is used by several files
118    ]
119
120sys.path[1:1] = extra_python_paths
121
122from m5.util import compareVersions, readCommand
123from m5.util.terminal import get_termcap
124
125help_texts = {
126    "options" : "",
127    "global_vars" : "",
128    "local_vars" : ""
129}
130
131Export("help_texts")
132
133
134# There's a bug in scons in that (1) by default, the help texts from
135# AddOption() are supposed to be displayed when you type 'scons -h'
136# and (2) you can override the help displayed by 'scons -h' using the
137# Help() function, but these two features are incompatible: once
138# you've overridden the help text using Help(), there's no way to get
139# at the help texts from AddOptions.  See:
140#     http://scons.tigris.org/issues/show_bug.cgi?id=2356
141#     http://scons.tigris.org/issues/show_bug.cgi?id=2611
142# This hack lets us extract the help text from AddOptions and
143# re-inject it via Help().  Ideally someday this bug will be fixed and
144# we can just use AddOption directly.
145def AddLocalOption(*args, **kwargs):
146    col_width = 30
147
148    help = "  " + ", ".join(args)
149    if "help" in kwargs:
150        length = len(help)
151        if length >= col_width:
152            help += "\n" + " " * col_width
153        else:
154            help += " " * (col_width - length)
155        help += kwargs["help"]
156    help_texts["options"] += help + "\n"
157
158    AddOption(*args, **kwargs)
159
160AddLocalOption('--colors', dest='use_colors', action='store_true',
161               help="Add color to abbreviated scons output")
162AddLocalOption('--no-colors', dest='use_colors', action='store_false',
163               help="Don't add color to abbreviated scons output")
164AddLocalOption('--default', dest='default', type='string', action='store',
165               help='Override which build_opts file to use for defaults')
166AddLocalOption('--ignore-style', dest='ignore_style', action='store_true',
167               help='Disable style checking hooks')
168AddLocalOption('--no-lto', dest='no_lto', action='store_true',
169               help='Disable Link-Time Optimization for fast')
170AddLocalOption('--update-ref', dest='update_ref', action='store_true',
171               help='Update test reference outputs')
172AddLocalOption('--verbose', dest='verbose', action='store_true',
173               help='Print full tool command lines')
174
175termcap = get_termcap(GetOption('use_colors'))
176
177########################################################################
178#
179# Set up the main build environment.
180#
181########################################################################
182use_vars = set([ 'AS', 'AR', 'CC', 'CXX', 'HOME', 'LD_LIBRARY_PATH',
183                 'LIBRARY_PATH', 'PATH', 'PKG_CONFIG_PATH', 'PYTHONPATH',
184                 'RANLIB', 'SWIG' ])
185
186use_prefixes = [
187    "M5",           # M5 configuration (e.g., path to kernels)
188    "DISTCC_",      # distcc (distributed compiler wrapper) configuration
189    "CCACHE_",      # ccache (caching compiler wrapper) configuration
190    "CCC_",         # clang static analyzer configuration
191    ]
192
193use_env = {}
194for key,val in os.environ.iteritems():
195    if key in use_vars or \
196            any([key.startswith(prefix) for prefix in use_prefixes]):
197        use_env[key] = val
198
199main = Environment(ENV=use_env)
200main.Decider('MD5-timestamp')
201main.root = Dir(".")         # The current directory (where this file lives).
202main.srcdir = Dir("src")     # The source directory
203
204main_dict_keys = main.Dictionary().keys()
205
206# Check that we have a C/C++ compiler
207if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
208    print "No C++ compiler installed (package g++ on Ubuntu and RedHat)"
209    Exit(1)
210
211# Check that swig is present
212if not 'SWIG' in main_dict_keys:
213    print "swig is not installed (package swig on Ubuntu and RedHat)"
214    Exit(1)
215
216# add useful python code PYTHONPATH so it can be used by subprocesses
217# as well
218main.AppendENVPath('PYTHONPATH', extra_python_paths)
219
220########################################################################
221#
222# Mercurial Stuff.
223#
224# If the gem5 directory is a mercurial repository, we should do some
225# extra things.
226#
227########################################################################
228
229hgdir = main.root.Dir(".hg")
230
231mercurial_style_message = """
232You're missing the gem5 style hook, which automatically checks your code
233against the gem5 style rules on hg commit and qrefresh commands.  This
234script will now install the hook in your .hg/hgrc file.
235Press enter to continue, or ctrl-c to abort: """
236
237mercurial_style_hook = """
238# The following lines were automatically added by gem5/SConstruct
239# to provide the gem5 style-checking hooks
240[extensions]
241style = %s/util/style.py
242
243[hooks]
244pretxncommit.style = python:style.check_style
245pre-qrefresh.style = python:style.check_style
246# End of SConstruct additions
247
248""" % (main.root.abspath)
249
250mercurial_lib_not_found = """
251Mercurial libraries cannot be found, ignoring style hook.  If
252you are a gem5 developer, please fix this and run the style
253hook. It is important.
254"""
255
256# Check for style hook and prompt for installation if it's not there.
257# Skip this if --ignore-style was specified, there's no .hg dir to
258# install a hook in, or there's no interactive terminal to prompt.
259if not GetOption('ignore_style') and hgdir.exists() and sys.stdin.isatty():
260    style_hook = True
261    try:
262        from mercurial import ui
263        ui = ui.ui()
264        ui.readconfig(hgdir.File('hgrc').abspath)
265        style_hook = ui.config('hooks', 'pretxncommit.style', None) and \
266                     ui.config('hooks', 'pre-qrefresh.style', None)
267    except ImportError:
268        print mercurial_lib_not_found
269
270    if not style_hook:
271        print mercurial_style_message,
272        # continue unless user does ctrl-c/ctrl-d etc.
273        try:
274            raw_input()
275        except:
276            print "Input exception, exiting scons.\n"
277            sys.exit(1)
278        hgrc_path = '%s/.hg/hgrc' % main.root.abspath
279        print "Adding style hook to", hgrc_path, "\n"
280        try:
281            hgrc = open(hgrc_path, 'a')
282            hgrc.write(mercurial_style_hook)
283            hgrc.close()
284        except:
285            print "Error updating", hgrc_path
286            sys.exit(1)
287
288
289###################################################
290#
291# Figure out which configurations to set up based on the path(s) of
292# the target(s).
293#
294###################################################
295
296# Find default configuration & binary.
297Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))
298
299# helper function: find last occurrence of element in list
300def rfind(l, elt, offs = -1):
301    for i in range(len(l)+offs, 0, -1):
302        if l[i] == elt:
303            return i
304    raise ValueError, "element not found"
305
306# Take a list of paths (or SCons Nodes) and return a list with all
307# paths made absolute and ~-expanded.  Paths will be interpreted
308# relative to the launch directory unless a different root is provided
309def makePathListAbsolute(path_list, root=GetLaunchDir()):
310    return [abspath(joinpath(root, expanduser(str(p))))
311            for p in path_list]
312
313# Each target must have 'build' in the interior of the path; the
314# directory below this will determine the build parameters.  For
315# example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
316# recognize that ALPHA_SE specifies the configuration because it
317# follow 'build' in the build path.
318
319# The funky assignment to "[:]" is needed to replace the list contents
320# in place rather than reassign the symbol to a new list, which
321# doesn't work (obviously!).
322BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
323
324# Generate a list of the unique build roots and configs that the
325# collected targets reference.
326variant_paths = []
327build_root = None
328for t in BUILD_TARGETS:
329    path_dirs = t.split('/')
330    try:
331        build_top = rfind(path_dirs, 'build', -2)
332    except:
333        print "Error: no non-leaf 'build' dir found on target path", t
334        Exit(1)
335    this_build_root = joinpath('/',*path_dirs[:build_top+1])
336    if not build_root:
337        build_root = this_build_root
338    else:
339        if this_build_root != build_root:
340            print "Error: build targets not under same build root\n"\
341                  "  %s\n  %s" % (build_root, this_build_root)
342            Exit(1)
343    variant_path = joinpath('/',*path_dirs[:build_top+2])
344    if variant_path not in variant_paths:
345        variant_paths.append(variant_path)
346
347# Make sure build_root exists (might not if this is the first build there)
348if not isdir(build_root):
349    mkdir(build_root)
350main['BUILDROOT'] = build_root
351
352Export('main')
353
354main.SConsignFile(joinpath(build_root, "sconsign"))
355
356# Default duplicate option is to use hard links, but this messes up
357# when you use emacs to edit a file in the target dir, as emacs moves
358# file to file~ then copies to file, breaking the link.  Symbolic
359# (soft) links work better.
360main.SetOption('duplicate', 'soft-copy')
361
362#
363# Set up global sticky variables... these are common to an entire build
364# tree (not specific to a particular build like ALPHA_SE)
365#
366
367global_vars_file = joinpath(build_root, 'variables.global')
368
369global_vars = Variables(global_vars_file, args=ARGUMENTS)
370
371global_vars.AddVariables(
372    ('CC', 'C compiler', environ.get('CC', main['CC'])),
373    ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
374    ('SWIG', 'SWIG tool', environ.get('SWIG', main['SWIG'])),
375    ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
376    ('BATCH', 'Use batch pool for build and tests', False),
377    ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
378    ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
379    ('EXTRAS', 'Add extra directories to the compilation', '')
380    )
381
382# Update main environment with values from ARGUMENTS & global_vars_file
383global_vars.Update(main)
384help_texts["global_vars"] += global_vars.GenerateHelpText(main)
385
386# Save sticky variable settings back to current variables file
387global_vars.Save(global_vars_file, main)
388
389# Parse EXTRAS variable to build list of all directories where we're
390# look for sources etc.  This list is exported as extras_dir_list.
391base_dir = main.srcdir.abspath
392if main['EXTRAS']:
393    extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
394else:
395    extras_dir_list = []
396
397Export('base_dir')
398Export('extras_dir_list')
399
400# the ext directory should be on the #includes path
401main.Append(CPPPATH=[Dir('ext')])
402
403def strip_build_path(path, env):
404    path = str(path)
405    variant_base = env['BUILDROOT'] + os.path.sep
406    if path.startswith(variant_base):
407        path = path[len(variant_base):]
408    elif path.startswith('build/'):
409        path = path[6:]
410    return path
411
412# Generate a string of the form:
413#   common/path/prefix/src1, src2 -> tgt1, tgt2
414# to print while building.
415class Transform(object):
416    # all specific color settings should be here and nowhere else
417    tool_color = termcap.Normal
418    pfx_color = termcap.Yellow
419    srcs_color = termcap.Yellow + termcap.Bold
420    arrow_color = termcap.Blue + termcap.Bold
421    tgts_color = termcap.Yellow + termcap.Bold
422
423    def __init__(self, tool, max_sources=99):
424        self.format = self.tool_color + (" [%8s] " % tool) \
425                      + self.pfx_color + "%s" \
426                      + self.srcs_color + "%s" \
427                      + self.arrow_color + " -> " \
428                      + self.tgts_color + "%s" \
429                      + termcap.Normal
430        self.max_sources = max_sources
431
432    def __call__(self, target, source, env, for_signature=None):
433        # truncate source list according to max_sources param
434        source = source[0:self.max_sources]
435        def strip(f):
436            return strip_build_path(str(f), env)
437        if len(source) > 0:
438            srcs = map(strip, source)
439        else:
440            srcs = ['']
441        tgts = map(strip, target)
442        # surprisingly, os.path.commonprefix is a dumb char-by-char string
443        # operation that has nothing to do with paths.
444        com_pfx = os.path.commonprefix(srcs + tgts)
445        com_pfx_len = len(com_pfx)
446        if com_pfx:
447            # do some cleanup and sanity checking on common prefix
448            if com_pfx[-1] == ".":
449                # prefix matches all but file extension: ok
450                # back up one to change 'foo.cc -> o' to 'foo.cc -> .o'
451                com_pfx = com_pfx[0:-1]
452            elif com_pfx[-1] == "/":
453                # common prefix is directory path: OK
454                pass
455            else:
456                src0_len = len(srcs[0])
457                tgt0_len = len(tgts[0])
458                if src0_len == com_pfx_len:
459                    # source is a substring of target, OK
460                    pass
461                elif tgt0_len == com_pfx_len:
462                    # target is a substring of source, need to back up to
463                    # avoid empty string on RHS of arrow
464                    sep_idx = com_pfx.rfind(".")
465                    if sep_idx != -1:
466                        com_pfx = com_pfx[0:sep_idx]
467                    else:
468                        com_pfx = ''
469                elif src0_len > com_pfx_len and srcs[0][com_pfx_len] == ".":
470                    # still splitting at file extension: ok
471                    pass
472                else:
473                    # probably a fluke; ignore it
474                    com_pfx = ''
475        # recalculate length in case com_pfx was modified
476        com_pfx_len = len(com_pfx)
477        def fmt(files):
478            f = map(lambda s: s[com_pfx_len:], files)
479            return ', '.join(f)
480        return self.format % (com_pfx, fmt(srcs), fmt(tgts))
481
482Export('Transform')
483
484# enable the regression script to use the termcap
485main['TERMCAP'] = termcap
486
487if GetOption('verbose'):
488    def MakeAction(action, string, *args, **kwargs):
489        return Action(action, *args, **kwargs)
490else:
491    MakeAction = Action
492    main['CCCOMSTR']        = Transform("CC")
493    main['CXXCOMSTR']       = Transform("CXX")
494    main['ASCOMSTR']        = Transform("AS")
495    main['SWIGCOMSTR']      = Transform("SWIG")
496    main['ARCOMSTR']        = Transform("AR", 0)
497    main['LINKCOMSTR']      = Transform("LINK", 0)
498    main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
499    main['M4COMSTR']        = Transform("M4")
500    main['SHCCCOMSTR']      = Transform("SHCC")
501    main['SHCXXCOMSTR']     = Transform("SHCXX")
502Export('MakeAction')
503
504# Initialize the Link-Time Optimization (LTO) flags
505main['LTO_CCFLAGS'] = []
506main['LTO_LDFLAGS'] = []
507
508# According to the readme, tcmalloc works best if the compiler doesn't
509# assume that we're using the builtin malloc and friends. These flags
510# are compiler-specific, so we need to set them after we detect which
511# compiler we're using.
512main['TCMALLOC_CCFLAGS'] = []
513
514CXX_version = readCommand([main['CXX'],'--version'], exception=False)
515CXX_V = readCommand([main['CXX'],'-V'], exception=False)
516
517main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
518main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
519if main['GCC'] + main['CLANG'] > 1:
520    print 'Error: How can we have two at the same time?'
521    Exit(1)
522
523# Set up default C++ compiler flags
524if main['GCC'] or main['CLANG']:
525    # As gcc and clang share many flags, do the common parts here
526    main.Append(CCFLAGS=['-pipe'])
527    main.Append(CCFLAGS=['-fno-strict-aliasing'])
528    # Enable -Wall and then disable the few warnings that we
529    # consistently violate
530    main.Append(CCFLAGS=['-Wall', '-Wno-sign-compare', '-Wundef'])
531    # We always compile using C++11, but only gcc >= 4.7 and clang 3.1
532    # actually use that name, so we stick with c++0x
533    main.Append(CXXFLAGS=['-std=c++0x'])
534    # Add selected sanity checks from -Wextra
535    main.Append(CXXFLAGS=['-Wmissing-field-initializers',
536                          '-Woverloaded-virtual'])
537else:
538    print termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal,
539    print "Don't know what compiler options to use for your compiler."
540    print termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX']
541    print termcap.Yellow + '       version:' + termcap.Normal,
542    if not CXX_version:
543        print termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +\
544               termcap.Normal
545    else:
546        print CXX_version.replace('\n', '<nl>')
547    print "       If you're trying to use a compiler other than GCC"
548    print "       or clang, there appears to be something wrong with your"
549    print "       environment."
550    print "       "
551    print "       If you are trying to use a compiler other than those listed"
552    print "       above you will need to ease fix SConstruct and "
553    print "       src/SConscript to support that compiler."
554    Exit(1)
555
556if main['GCC']:
557    # Check for a supported version of gcc, >= 4.4 is needed for c++0x
558    # support. See http://gcc.gnu.org/projects/cxx0x.html for details
559    gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
560    if compareVersions(gcc_version, "4.4") < 0:
561        print 'Error: gcc version 4.4 or newer required.'
562        print '       Installed version:', gcc_version
563        Exit(1)
564
565    main['GCC_VERSION'] = gcc_version
566
567    # Check for versions with bugs
568    if not compareVersions(gcc_version, '4.4.1') or \
569       not compareVersions(gcc_version, '4.4.2'):
570        print 'Info: Tree vectorizer in GCC 4.4.1 & 4.4.2 is buggy, disabling.'
571        main.Append(CCFLAGS=['-fno-tree-vectorize'])
572
573    # LTO support is only really working properly from 4.6 and beyond
574    if compareVersions(gcc_version, '4.6') >= 0:
575        # Add the appropriate Link-Time Optimization (LTO) flags
576        # unless LTO is explicitly turned off. Note that these flags
577        # are only used by the fast target.
578        if not GetOption('no_lto'):
579            # Pass the LTO flag when compiling to produce GIMPLE
580            # output, we merely create the flags here and only append
581            # them later/
582            main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
583
584            # Use the same amount of jobs for LTO as we are running
585            # scons with, we hardcode the use of the linker plugin
586            # which requires either gold or GNU ld >= 2.21
587            main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs'),
588                                   '-fuse-linker-plugin']
589
590    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
591                                  '-fno-builtin-realloc', '-fno-builtin-free'])
592
593elif main['CLANG']:
594    # Check for a supported version of clang, >= 2.9 is needed to
595    # support similar features as gcc 4.4. See
596    # http://clang.llvm.org/cxx_status.html for details
597    clang_version_re = re.compile(".* version (\d+\.\d+)")
598    clang_version_match = clang_version_re.match(CXX_version)
599    if (clang_version_match):
600        clang_version = clang_version_match.groups()[0]
601        if compareVersions(clang_version, "2.9") < 0:
602            print 'Error: clang version 2.9 or newer required.'
603            print '       Installed version:', clang_version
604            Exit(1)
605    else:
606        print 'Error: Unable to determine clang version.'
607        Exit(1)
608
609    # clang has a few additional warnings that we disable,
610    # tautological comparisons are allowed due to unsigned integers
611    # being compared to constants that happen to be 0, and extraneous
612    # parantheses are allowed due to Ruby's printing of the AST,
613    # finally self assignments are allowed as the generated CPU code
614    # is relying on this
615    main.Append(CCFLAGS=['-Wno-tautological-compare',
616                         '-Wno-parentheses',
617                         '-Wno-self-assign'])
618
619    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
620
621    # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
622    # opposed to libstdc++ to make the transition from TR1 to
623    # C++11. See http://libcxx.llvm.org. However, clang has chosen a
624    # strict implementation of the C++11 standard, and does not allow
625    # incomplete types in template arguments (besides unique_ptr and
626    # shared_ptr), and the libc++ STL containers create problems in
627    # combination with the current gem5 code. For now, we stick with
628    # libstdc++ and use the TR1 namespace.
629    # if sys.platform == "darwin":
630    #     main.Append(CXXFLAGS=['-stdlib=libc++'])
631
632else:
633    print termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal,
634    print "Don't know what compiler options to use for your compiler."
635    print termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX']
636    print termcap.Yellow + '       version:' + termcap.Normal,
637    if not CXX_version:
638        print termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +\
639               termcap.Normal
640    else:
641        print CXX_version.replace('\n', '<nl>')
642    print "       If you're trying to use a compiler other than GCC"
643    print "       or clang, there appears to be something wrong with your"
644    print "       environment."
645    print "       "
646    print "       If you are trying to use a compiler other than those listed"
647    print "       above you will need to ease fix SConstruct and "
648    print "       src/SConscript to support that compiler."
649    Exit(1)
650
651# Set up common yacc/bison flags (needed for Ruby)
652main['YACCFLAGS'] = '-d'
653main['YACCHXXFILESUFFIX'] = '.hh'
654
655# Do this after we save setting back, or else we'll tack on an
656# extra 'qdo' every time we run scons.
657if main['BATCH']:
658    main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
659    main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
660    main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
661    main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
662    main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
663
664if sys.platform == 'cygwin':
665    # cygwin has some header file issues...
666    main.Append(CCFLAGS=["-Wno-uninitialized"])
667
668# Check for the protobuf compiler
669protoc_version = readCommand([main['PROTOC'], '--version'],
670                             exception='').split()
671
672# First two words should be "libprotoc x.y.z"
673if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
674    print termcap.Yellow + termcap.Bold + \
675        'Warning: Protocol buffer compiler (protoc) not found.\n' + \
676        '         Please install protobuf-compiler for tracing support.' + \
677        termcap.Normal
678    main['PROTOC'] = False
679else:
680    # Based on the availability of the compress stream wrappers,
681    # require 2.1.0
682    min_protoc_version = '2.1.0'
683    if compareVersions(protoc_version[1], min_protoc_version) < 0:
684        print termcap.Yellow + termcap.Bold + \
685            'Warning: protoc version', min_protoc_version, \
686            'or newer required.\n' + \
687            '         Installed version:', protoc_version[1], \
688            termcap.Normal
689        main['PROTOC'] = False
690    else:
691        # Attempt to determine the appropriate include path and
692        # library path using pkg-config, that means we also need to
693        # check for pkg-config. Note that it is possible to use
694        # protobuf without the involvement of pkg-config. Later on we
695        # check go a library config check and at that point the test
696        # will fail if libprotobuf cannot be found.
697        if readCommand(['pkg-config', '--version'], exception=''):
698            try:
699                # Attempt to establish what linking flags to add for protobuf
700                # using pkg-config
701                main.ParseConfig('pkg-config --cflags --libs-only-L protobuf')
702            except:
703                print termcap.Yellow + termcap.Bold + \
704                    'Warning: pkg-config could not get protobuf flags.' + \
705                    termcap.Normal
706
707# Check for SWIG
708if not main.has_key('SWIG'):
709    print 'Error: SWIG utility not found.'
710    print '       Please install (see http://www.swig.org) and retry.'
711    Exit(1)
712
713# Check for appropriate SWIG version
714swig_version = readCommand([main['SWIG'], '-version'], exception='').split()
715# First 3 words should be "SWIG Version x.y.z"
716if len(swig_version) < 3 or \
717        swig_version[0] != 'SWIG' or swig_version[1] != 'Version':
718    print 'Error determining SWIG version.'
719    Exit(1)
720
721min_swig_version = '1.3.34'
722if compareVersions(swig_version[2], min_swig_version) < 0:
723    print 'Error: SWIG version', min_swig_version, 'or newer required.'
724    print '       Installed version:', swig_version[2]
725    Exit(1)
726
727if swig_version[2] == "2.0.9":
728    print '\n' + termcap.Yellow + termcap.Bold + \
729        'Warning: SWIG version 2.0.9 sometimes generates broken code.\n' + \
730        termcap.Normal + \
731        'This problem only affects some platforms and some Python\n' + \
732        'versions. See the following SWIG bug report for details:\n' + \
733        'http://sourceforge.net/p/swig/bugs/1297/\n'
734
735
736# Set up SWIG flags & scanner
737swig_flags=Split('-c++ -python -modern -templatereduce $_CPPINCFLAGS')
738main.Append(SWIGFLAGS=swig_flags)
739
740# filter out all existing swig scanners, they mess up the dependency
741# stuff for some reason
742scanners = []
743for scanner in main['SCANNERS']:
744    skeys = scanner.skeys
745    if skeys == '.i':
746        continue
747
748    if isinstance(skeys, (list, tuple)) and '.i' in skeys:
749        continue
750
751    scanners.append(scanner)
752
753# add the new swig scanner that we like better
754from SCons.Scanner import ClassicCPP as CPPScanner
755swig_inc_re = '^[ \t]*[%,#][ \t]*(?:include|import)[ \t]*(<|")([^>"]+)(>|")'
756scanners.append(CPPScanner("SwigScan", [ ".i" ], "CPPPATH", swig_inc_re))
757
758# replace the scanners list that has what we want
759main['SCANNERS'] = scanners
760
761# Add a custom Check function to the Configure context so that we can
762# figure out if the compiler adds leading underscores to global
763# variables.  This is needed for the autogenerated asm files that we
764# use for embedding the python code.
765def CheckLeading(context):
766    context.Message("Checking for leading underscore in global variables...")
767    # 1) Define a global variable called x from asm so the C compiler
768    #    won't change the symbol at all.
769    # 2) Declare that variable.
770    # 3) Use the variable
771    #
772    # If the compiler prepends an underscore, this will successfully
773    # link because the external symbol 'x' will be called '_x' which
774    # was defined by the asm statement.  If the compiler does not
775    # prepend an underscore, this will not successfully link because
776    # '_x' will have been defined by assembly, while the C portion of
777    # the code will be trying to use 'x'
778    ret = context.TryLink('''
779        asm(".globl _x; _x: .byte 0");
780        extern int x;
781        int main() { return x; }
782        ''', extension=".c")
783    context.env.Append(LEADING_UNDERSCORE=ret)
784    context.Result(ret)
785    return ret
786
787# Platform-specific configuration.  Note again that we assume that all
788# builds under a given build root run on the same host platform.
789conf = Configure(main,
790                 conf_dir = joinpath(build_root, '.scons_config'),
791                 log_file = joinpath(build_root, 'scons_config.log'),
792                 custom_tests = { 'CheckLeading' : CheckLeading })
793
794# Check for leading underscores.  Don't really need to worry either
795# way so don't need to check the return code.
796conf.CheckLeading()
797
798# Check if we should compile a 64 bit binary on Mac OS X/Darwin
799try:
800    import platform
801    uname = platform.uname()
802    if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
803        if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
804            main.Append(CCFLAGS=['-arch', 'x86_64'])
805            main.Append(CFLAGS=['-arch', 'x86_64'])
806            main.Append(LINKFLAGS=['-arch', 'x86_64'])
807            main.Append(ASFLAGS=['-arch', 'x86_64'])
808except:
809    pass
810
811# Recent versions of scons substitute a "Null" object for Configure()
812# when configuration isn't necessary, e.g., if the "--help" option is
813# present.  Unfortuantely this Null object always returns false,
814# breaking all our configuration checks.  We replace it with our own
815# more optimistic null object that returns True instead.
816if not conf:
817    def NullCheck(*args, **kwargs):
818        return True
819
820    class NullConf:
821        def __init__(self, env):
822            self.env = env
823        def Finish(self):
824            return self.env
825        def __getattr__(self, mname):
826            return NullCheck
827
828    conf = NullConf(main)
829
830# Find Python include and library directories for embedding the
831# interpreter.  For consistency, we will use the same Python
832# installation used to run scons (and thus this script).  If you want
833# to link in an alternate version, see above for instructions on how
834# to invoke scons with a different copy of the Python interpreter.
835from distutils import sysconfig
836
837py_getvar = sysconfig.get_config_var
838
839py_debug = getattr(sys, 'pydebug', False)
840py_version = 'python' + py_getvar('VERSION') + (py_debug and "_d" or "")
841
842py_general_include = sysconfig.get_python_inc()
843py_platform_include = sysconfig.get_python_inc(plat_specific=True)
844py_includes = [ py_general_include ]
845if py_platform_include != py_general_include:
846    py_includes.append(py_platform_include)
847
848py_lib_path = [ py_getvar('LIBDIR') ]
849# add the prefix/lib/pythonX.Y/config dir, but only if there is no
850# shared library in prefix/lib/.
851if not py_getvar('Py_ENABLE_SHARED'):
852    py_lib_path.append(py_getvar('LIBPL'))
853    # Python requires the flags in LINKFORSHARED to be added the
854    # linker flags when linking with a statically with Python. Failing
855    # to do so can lead to errors from the Python's dynamic module
856    # loader at start up.
857    main.Append(LINKFLAGS=[py_getvar('LINKFORSHARED').split()])
858
859py_libs = []
860for lib in py_getvar('LIBS').split() + py_getvar('SYSLIBS').split():
861    if not lib.startswith('-l'):
862        # Python requires some special flags to link (e.g. -framework
863        # common on OS X systems), assume appending preserves order
864        main.Append(LINKFLAGS=[lib])
865    else:
866        lib = lib[2:]
867        if lib not in py_libs:
868            py_libs.append(lib)
869py_libs.append(py_version)
870
871main.Append(CPPPATH=py_includes)
872main.Append(LIBPATH=py_lib_path)
873
874# Cache build files in the supplied directory.
875if main['M5_BUILD_CACHE']:
876    print 'Using build cache located at', main['M5_BUILD_CACHE']
877    CacheDir(main['M5_BUILD_CACHE'])
878
879
880# verify that this stuff works
881if not conf.CheckHeader('Python.h', '<>'):
882    print "Error: can't find Python.h header in", py_includes
883    print "Install Python headers (package python-dev on Ubuntu and RedHat)"
884    Exit(1)
885
886for lib in py_libs:
887    if not conf.CheckLib(lib):
888        print "Error: can't find library %s required by python" % lib
889        Exit(1)
890
891# On Solaris you need to use libsocket for socket ops
892if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
893   if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
894       print "Can't find library with socket calls (e.g. accept())"
895       Exit(1)
896
897# Check for zlib.  If the check passes, libz will be automatically
898# added to the LIBS environment variable.
899if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
900    print 'Error: did not find needed zlib compression library '\
901          'and/or zlib.h header file.'
902    print '       Please install zlib and try again.'
903    Exit(1)
904
905# If we have the protobuf compiler, also make sure we have the
906# development libraries. If the check passes, libprotobuf will be
907# automatically added to the LIBS environment variable. After
908# this, we can use the HAVE_PROTOBUF flag to determine if we have
909# got both protoc and libprotobuf available.
910main['HAVE_PROTOBUF'] = main['PROTOC'] and \
911    conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
912                            'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
913
914# If we have the compiler but not the library, print another warning.
915if main['PROTOC'] and not main['HAVE_PROTOBUF']:
916    print termcap.Yellow + termcap.Bold + \
917        'Warning: did not find protocol buffer library and/or headers.\n' + \
918    '       Please install libprotobuf-dev for tracing support.' + \
919    termcap.Normal
920
921# Check for librt.
922have_posix_clock = \
923    conf.CheckLibWithHeader(None, 'time.h', 'C',
924                            'clock_nanosleep(0,0,NULL,NULL);') or \
925    conf.CheckLibWithHeader('rt', 'time.h', 'C',
926                            'clock_nanosleep(0,0,NULL,NULL);')
927
928if conf.CheckLib('tcmalloc'):
929    main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
930elif conf.CheckLib('tcmalloc_minimal'):
931    main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
932else:
933    print termcap.Yellow + termcap.Bold + \
934          "You can get a 12% performance improvement by installing tcmalloc "\
935          "(libgoogle-perftools-dev package on Ubuntu or RedHat)." + \
936          termcap.Normal
937
938if not have_posix_clock:
939    print "Can't find library for POSIX clocks."
940
941# Check for <fenv.h> (C99 FP environment control)
942have_fenv = conf.CheckHeader('fenv.h', '<>')
943if not have_fenv:
944    print "Warning: Header file <fenv.h> not found."
945    print "         This host has no IEEE FP rounding mode control."
946
947######################################################################
948#
949# Finish the configuration
950#
951main = conf.Finish()
952
953######################################################################
954#
955# Collect all non-global variables
956#
957
958# Define the universe of supported ISAs
959all_isa_list = [ ]
960Export('all_isa_list')
961
962class CpuModel(object):
963    '''The CpuModel class encapsulates everything the ISA parser needs to
964    know about a particular CPU model.'''
965
966    # Dict of available CPU model objects.  Accessible as CpuModel.dict.
967    dict = {}
968    list = []
969    defaults = []
970
971    # Constructor.  Automatically adds models to CpuModel.dict.
972    def __init__(self, name, filename, includes, strings, default=False):
973        self.name = name           # name of model
974        self.filename = filename   # filename for output exec code
975        self.includes = includes   # include files needed in exec file
976        # The 'strings' dict holds all the per-CPU symbols we can
977        # substitute into templates etc.
978        self.strings = strings
979
980        # This cpu is enabled by default
981        self.default = default
982
983        # Add self to dict
984        if name in CpuModel.dict:
985            raise AttributeError, "CpuModel '%s' already registered" % name
986        CpuModel.dict[name] = self
987        CpuModel.list.append(name)
988
989Export('CpuModel')
990
991# Sticky variables get saved in the variables file so they persist from
992# one invocation to the next (unless overridden, in which case the new
993# value becomes sticky).
994sticky_vars = Variables(args=ARGUMENTS)
995Export('sticky_vars')
996
997# Sticky variables that should be exported
998export_vars = []
999Export('export_vars')
1000
1001# For Ruby
1002all_protocols = []
1003Export('all_protocols')
1004protocol_dirs = []
1005Export('protocol_dirs')
1006slicc_includes = []
1007Export('slicc_includes')
1008
1009# Walk the tree and execute all SConsopts scripts that wil add to the
1010# above variables
1011if not GetOption('verbose'):
1012    print "Reading SConsopts"
1013for bdir in [ base_dir ] + extras_dir_list:
1014    if not isdir(bdir):
1015        print "Error: directory '%s' does not exist" % bdir
1016        Exit(1)
1017    for root, dirs, files in os.walk(bdir):
1018        if 'SConsopts' in files:
1019            if GetOption('verbose'):
1020                print "Reading", joinpath(root, 'SConsopts')
1021            SConscript(joinpath(root, 'SConsopts'))
1022
1023all_isa_list.sort()
1024
1025sticky_vars.AddVariables(
1026    EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
1027    ListVariable('CPU_MODELS', 'CPU models',
1028                 sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
1029                 sorted(CpuModel.list)),
1030    BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
1031                 False),
1032    BoolVariable('SS_COMPATIBLE_FP',
1033                 'Make floating-point results compatible with SimpleScalar',
1034                 False),
1035    BoolVariable('USE_SSE2',
1036                 'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
1037                 False),
1038    BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
1039    BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
1040    BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability', False),
1041    EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1042                  all_protocols),
1043    )
1044
1045# These variables get exported to #defines in config/*.hh (see src/SConscript).
1046export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'CP_ANNOTATE',
1047                'USE_POSIX_CLOCK', 'PROTOCOL', 'HAVE_PROTOBUF']
1048
1049###################################################
1050#
1051# Define a SCons builder for configuration flag headers.
1052#
1053###################################################
1054
1055# This function generates a config header file that #defines the
1056# variable symbol to the current variable setting (0 or 1).  The source
1057# operands are the name of the variable and a Value node containing the
1058# value of the variable.
1059def build_config_file(target, source, env):
1060    (variable, value) = [s.get_contents() for s in source]
1061    f = file(str(target[0]), 'w')
1062    print >> f, '#define', variable, value
1063    f.close()
1064    return None
1065
1066# Combine the two functions into a scons Action object.
1067config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1068
1069# The emitter munges the source & target node lists to reflect what
1070# we're really doing.
1071def config_emitter(target, source, env):
1072    # extract variable name from Builder arg
1073    variable = str(target[0])
1074    # True target is config header file
1075    target = joinpath('config', variable.lower() + '.hh')
1076    val = env[variable]
1077    if isinstance(val, bool):
1078        # Force value to 0/1
1079        val = int(val)
1080    elif isinstance(val, str):
1081        val = '"' + val + '"'
1082
1083    # Sources are variable name & value (packaged in SCons Value nodes)
1084    return ([target], [Value(variable), Value(val)])
1085
1086config_builder = Builder(emitter = config_emitter, action = config_action)
1087
1088main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1089
1090# libelf build is shared across all configs in the build root.
1091main.SConscript('ext/libelf/SConscript',
1092                variant_dir = joinpath(build_root, 'libelf'))
1093
1094# gzstream build is shared across all configs in the build root.
1095main.SConscript('ext/gzstream/SConscript',
1096                variant_dir = joinpath(build_root, 'gzstream'))
1097
1098# libfdt build is shared across all configs in the build root.
1099main.SConscript('ext/libfdt/SConscript',
1100                variant_dir = joinpath(build_root, 'libfdt'))
1101
1102###################################################
1103#
1104# This function is used to set up a directory with switching headers
1105#
1106###################################################
1107
1108main['ALL_ISA_LIST'] = all_isa_list
1109def make_switching_dir(dname, switch_headers, env):
1110    # Generate the header.  target[0] is the full path of the output
1111    # header to generate.  'source' is a dummy variable, since we get the
1112    # list of ISAs from env['ALL_ISA_LIST'].
1113    def gen_switch_hdr(target, source, env):
1114        fname = str(target[0])
1115        f = open(fname, 'w')
1116        isa = env['TARGET_ISA'].lower()
1117        print >>f, '#include "%s/%s/%s"' % (dname, isa, basename(fname))
1118        f.close()
1119
1120    # Build SCons Action object. 'varlist' specifies env vars that this
1121    # action depends on; when env['ALL_ISA_LIST'] changes these actions
1122    # should get re-executed.
1123    switch_hdr_action = MakeAction(gen_switch_hdr,
1124                          Transform("GENERATE"), varlist=['ALL_ISA_LIST'])
1125
1126    # Instantiate actions for each header
1127    for hdr in switch_headers:
1128        env.Command(hdr, [], switch_hdr_action)
1129Export('make_switching_dir')
1130
1131###################################################
1132#
1133# Define build environments for selected configurations.
1134#
1135###################################################
1136
1137for variant_path in variant_paths:
1138    print "Building in", variant_path
1139
1140    # Make a copy of the build-root environment to use for this config.
1141    env = main.Clone()
1142    env['BUILDDIR'] = variant_path
1143
1144    # variant_dir is the tail component of build path, and is used to
1145    # determine the build parameters (e.g., 'ALPHA_SE')
1146    (build_root, variant_dir) = splitpath(variant_path)
1147
1148    # Set env variables according to the build directory config.
1149    sticky_vars.files = []
1150    # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1151    # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1152    # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1153    current_vars_file = joinpath(build_root, 'variables', variant_dir)
1154    if isfile(current_vars_file):
1155        sticky_vars.files.append(current_vars_file)
1156        print "Using saved variables file %s" % current_vars_file
1157    else:
1158        # Build dir-specific variables file doesn't exist.
1159
1160        # Make sure the directory is there so we can create it later
1161        opt_dir = dirname(current_vars_file)
1162        if not isdir(opt_dir):
1163            mkdir(opt_dir)
1164
1165        # Get default build variables from source tree.  Variables are
1166        # normally determined by name of $VARIANT_DIR, but can be
1167        # overridden by '--default=' arg on command line.
1168        default = GetOption('default')
1169        opts_dir = joinpath(main.root.abspath, 'build_opts')
1170        if default:
1171            default_vars_files = [joinpath(build_root, 'variables', default),
1172                                  joinpath(opts_dir, default)]
1173        else:
1174            default_vars_files = [joinpath(opts_dir, variant_dir)]
1175        existing_files = filter(isfile, default_vars_files)
1176        if existing_files:
1177            default_vars_file = existing_files[0]
1178            sticky_vars.files.append(default_vars_file)
1179            print "Variables file %s not found,\n  using defaults in %s" \
1180                  % (current_vars_file, default_vars_file)
1181        else:
1182            print "Error: cannot find variables file %s or " \
1183                  "default file(s) %s" \
1184                  % (current_vars_file, ' or '.join(default_vars_files))
1185            Exit(1)
1186
1187    # Apply current variable settings to env
1188    sticky_vars.Update(env)
1189
1190    help_texts["local_vars"] += \
1191        "Build variables for %s:\n" % variant_dir \
1192                 + sticky_vars.GenerateHelpText(env)
1193
1194    # Process variable settings.
1195
1196    if not have_fenv and env['USE_FENV']:
1197        print "Warning: <fenv.h> not available; " \
1198              "forcing USE_FENV to False in", variant_dir + "."
1199        env['USE_FENV'] = False
1200
1201    if not env['USE_FENV']:
1202        print "Warning: No IEEE FP rounding mode control in", variant_dir + "."
1203        print "         FP results may deviate slightly from other platforms."
1204
1205    if env['EFENCE']:
1206        env.Append(LIBS=['efence'])
1207
1208    # Save sticky variable settings back to current variables file
1209    sticky_vars.Save(current_vars_file, env)
1210
1211    if env['USE_SSE2']:
1212        env.Append(CCFLAGS=['-msse2'])
1213
1214    # The src/SConscript file sets up the build rules in 'env' according
1215    # to the configured variables.  It returns a list of environments,
1216    # one for each variant build (debug, opt, etc.)
1217    envList = SConscript('src/SConscript', variant_dir = variant_path,
1218                         exports = 'env')
1219
1220    # Set up the regression tests for each build.
1221    for e in envList:
1222        SConscript('tests/SConscript',
1223                   variant_dir = joinpath(variant_path, 'tests', e.Label),
1224                   exports = { 'env' : e }, duplicate = False)
1225
1226# base help text
1227Help('''
1228Usage: scons [scons options] [build variables] [target(s)]
1229
1230Extra scons options:
1231%(options)s
1232
1233Global build variables:
1234%(global_vars)s
1235
1236%(local_vars)s
1237''' % help_texts)
1238