SConstruct revision 8887
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
123
124help_texts = {
125    "options" : "",
126    "global_vars" : "",
127    "local_vars" : ""
128}
129
130Export("help_texts")
131
132
133# There's a bug in scons in that (1) by default, the help texts from
134# AddOption() are supposed to be displayed when you type 'scons -h'
135# and (2) you can override the help displayed by 'scons -h' using the
136# Help() function, but these two features are incompatible: once
137# you've overridden the help text using Help(), there's no way to get
138# at the help texts from AddOptions.  See:
139#     http://scons.tigris.org/issues/show_bug.cgi?id=2356
140#     http://scons.tigris.org/issues/show_bug.cgi?id=2611
141# This hack lets us extract the help text from AddOptions and
142# re-inject it via Help().  Ideally someday this bug will be fixed and
143# we can just use AddOption directly.
144def AddLocalOption(*args, **kwargs):
145    col_width = 30
146
147    help = "  " + ", ".join(args)
148    if "help" in kwargs:
149        length = len(help)
150        if length >= col_width:
151            help += "\n" + " " * col_width
152        else:
153            help += " " * (col_width - length)
154        help += kwargs["help"]
155    help_texts["options"] += help + "\n"
156
157    AddOption(*args, **kwargs)
158
159AddLocalOption('--colors', dest='use_colors', action='store_true',
160               help="Add color to abbreviated scons output")
161AddLocalOption('--no-colors', dest='use_colors', action='store_false',
162               help="Don't add color to abbreviated scons output")
163AddLocalOption('--default', dest='default', type='string', action='store',
164               help='Override which build_opts file to use for defaults')
165AddLocalOption('--ignore-style', dest='ignore_style', action='store_true',
166               help='Disable style checking hooks')
167AddLocalOption('--update-ref', dest='update_ref', action='store_true',
168               help='Update test reference outputs')
169AddLocalOption('--verbose', dest='verbose', action='store_true',
170               help='Print full tool command lines')
171
172use_colors = GetOption('use_colors')
173if use_colors:
174    from m5.util.terminal import termcap
175elif use_colors is None:
176    # option unspecified; default behavior is to use colors iff isatty
177    from m5.util.terminal import tty_termcap as termcap
178else:
179    from m5.util.terminal import no_termcap as termcap
180
181########################################################################
182#
183# Set up the main build environment.
184#
185########################################################################
186use_vars = set([ 'AS', 'AR', 'CC', 'CXX', 'HOME', 'LD_LIBRARY_PATH', 'PATH',
187                 'PYTHONPATH', 'RANLIB' ])
188
189use_env = {}
190for key,val in os.environ.iteritems():
191    if key in use_vars or key.startswith("M5"):
192        use_env[key] = val
193
194main = Environment(ENV=use_env)
195main.Decider('MD5-timestamp')
196main.SetOption('implicit_cache', 1)
197main.root = Dir(".")         # The current directory (where this file lives).
198main.srcdir = Dir("src")     # The source directory
199
200# add useful python code PYTHONPATH so it can be used by subprocesses
201# as well
202main.AppendENVPath('PYTHONPATH', extra_python_paths)
203
204########################################################################
205#
206# Mercurial Stuff.
207#
208# If the gem5 directory is a mercurial repository, we should do some
209# extra things.
210#
211########################################################################
212
213hgdir = main.root.Dir(".hg")
214
215mercurial_style_message = """
216You're missing the gem5 style hook, which automatically checks your code
217against the gem5 style rules on hg commit and qrefresh commands.  This
218script will now install the hook in your .hg/hgrc file.
219Press enter to continue, or ctrl-c to abort: """
220
221mercurial_style_hook = """
222# The following lines were automatically added by gem5/SConstruct
223# to provide the gem5 style-checking hooks
224[extensions]
225style = %s/util/style.py
226
227[hooks]
228pretxncommit.style = python:style.check_style
229pre-qrefresh.style = python:style.check_style
230# End of SConstruct additions
231
232""" % (main.root.abspath)
233
234mercurial_lib_not_found = """
235Mercurial libraries cannot be found, ignoring style hook.  If
236you are a gem5 developer, please fix this and run the style
237hook. It is important.
238"""
239
240# Check for style hook and prompt for installation if it's not there.
241# Skip this if --ignore-style was specified, there's no .hg dir to
242# install a hook in, or there's no interactive terminal to prompt.
243if not GetOption('ignore_style') and hgdir.exists() and sys.stdin.isatty():
244    style_hook = True
245    try:
246        from mercurial import ui
247        ui = ui.ui()
248        ui.readconfig(hgdir.File('hgrc').abspath)
249        style_hook = ui.config('hooks', 'pretxncommit.style', None) and \
250                     ui.config('hooks', 'pre-qrefresh.style', None)
251    except ImportError:
252        print mercurial_lib_not_found
253
254    if not style_hook:
255        print mercurial_style_message,
256        # continue unless user does ctrl-c/ctrl-d etc.
257        try:
258            raw_input()
259        except:
260            print "Input exception, exiting scons.\n"
261            sys.exit(1)
262        hgrc_path = '%s/.hg/hgrc' % main.root.abspath
263        print "Adding style hook to", hgrc_path, "\n"
264        try:
265            hgrc = open(hgrc_path, 'a')
266            hgrc.write(mercurial_style_hook)
267            hgrc.close()
268        except:
269            print "Error updating", hgrc_path
270            sys.exit(1)
271
272
273###################################################
274#
275# Figure out which configurations to set up based on the path(s) of
276# the target(s).
277#
278###################################################
279
280# Find default configuration & binary.
281Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))
282
283# helper function: find last occurrence of element in list
284def rfind(l, elt, offs = -1):
285    for i in range(len(l)+offs, 0, -1):
286        if l[i] == elt:
287            return i
288    raise ValueError, "element not found"
289
290# Take a list of paths (or SCons Nodes) and return a list with all
291# paths made absolute and ~-expanded.  Paths will be interpreted
292# relative to the launch directory unless a different root is provided
293def makePathListAbsolute(path_list, root=GetLaunchDir()):
294    return [abspath(joinpath(root, expanduser(str(p))))
295            for p in path_list]
296
297# Each target must have 'build' in the interior of the path; the
298# directory below this will determine the build parameters.  For
299# example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
300# recognize that ALPHA_SE specifies the configuration because it
301# follow 'build' in the build path.
302
303# The funky assignment to "[:]" is needed to replace the list contents
304# in place rather than reassign the symbol to a new list, which
305# doesn't work (obviously!).
306BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
307
308# Generate a list of the unique build roots and configs that the
309# collected targets reference.
310variant_paths = []
311build_root = None
312for t in BUILD_TARGETS:
313    path_dirs = t.split('/')
314    try:
315        build_top = rfind(path_dirs, 'build', -2)
316    except:
317        print "Error: no non-leaf 'build' dir found on target path", t
318        Exit(1)
319    this_build_root = joinpath('/',*path_dirs[:build_top+1])
320    if not build_root:
321        build_root = this_build_root
322    else:
323        if this_build_root != build_root:
324            print "Error: build targets not under same build root\n"\
325                  "  %s\n  %s" % (build_root, this_build_root)
326            Exit(1)
327    variant_path = joinpath('/',*path_dirs[:build_top+2])
328    if variant_path not in variant_paths:
329        variant_paths.append(variant_path)
330
331# Make sure build_root exists (might not if this is the first build there)
332if not isdir(build_root):
333    mkdir(build_root)
334main['BUILDROOT'] = build_root
335
336Export('main')
337
338main.SConsignFile(joinpath(build_root, "sconsign"))
339
340# Default duplicate option is to use hard links, but this messes up
341# when you use emacs to edit a file in the target dir, as emacs moves
342# file to file~ then copies to file, breaking the link.  Symbolic
343# (soft) links work better.
344main.SetOption('duplicate', 'soft-copy')
345
346#
347# Set up global sticky variables... these are common to an entire build
348# tree (not specific to a particular build like ALPHA_SE)
349#
350
351global_vars_file = joinpath(build_root, 'variables.global')
352
353global_vars = Variables(global_vars_file, args=ARGUMENTS)
354
355global_vars.AddVariables(
356    ('CC', 'C compiler', environ.get('CC', main['CC'])),
357    ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
358    ('BATCH', 'Use batch pool for build and tests', False),
359    ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
360    ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
361    ('EXTRAS', 'Add extra directories to the compilation', '')
362    )
363
364# Update main environment with values from ARGUMENTS & global_vars_file
365global_vars.Update(main)
366help_texts["global_vars"] += global_vars.GenerateHelpText(main)
367
368# Save sticky variable settings back to current variables file
369global_vars.Save(global_vars_file, main)
370
371# Parse EXTRAS variable to build list of all directories where we're
372# look for sources etc.  This list is exported as extras_dir_list.
373base_dir = main.srcdir.abspath
374if main['EXTRAS']:
375    extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
376else:
377    extras_dir_list = []
378
379Export('base_dir')
380Export('extras_dir_list')
381
382# the ext directory should be on the #includes path
383main.Append(CPPPATH=[Dir('ext')])
384
385def strip_build_path(path, env):
386    path = str(path)
387    variant_base = env['BUILDROOT'] + os.path.sep
388    if path.startswith(variant_base):
389        path = path[len(variant_base):]
390    elif path.startswith('build/'):
391        path = path[6:]
392    return path
393
394# Generate a string of the form:
395#   common/path/prefix/src1, src2 -> tgt1, tgt2
396# to print while building.
397class Transform(object):
398    # all specific color settings should be here and nowhere else
399    tool_color = termcap.Normal
400    pfx_color = termcap.Yellow
401    srcs_color = termcap.Yellow + termcap.Bold
402    arrow_color = termcap.Blue + termcap.Bold
403    tgts_color = termcap.Yellow + termcap.Bold
404
405    def __init__(self, tool, max_sources=99):
406        self.format = self.tool_color + (" [%8s] " % tool) \
407                      + self.pfx_color + "%s" \
408                      + self.srcs_color + "%s" \
409                      + self.arrow_color + " -> " \
410                      + self.tgts_color + "%s" \
411                      + termcap.Normal
412        self.max_sources = max_sources
413
414    def __call__(self, target, source, env, for_signature=None):
415        # truncate source list according to max_sources param
416        source = source[0:self.max_sources]
417        def strip(f):
418            return strip_build_path(str(f), env)
419        if len(source) > 0:
420            srcs = map(strip, source)
421        else:
422            srcs = ['']
423        tgts = map(strip, target)
424        # surprisingly, os.path.commonprefix is a dumb char-by-char string
425        # operation that has nothing to do with paths.
426        com_pfx = os.path.commonprefix(srcs + tgts)
427        com_pfx_len = len(com_pfx)
428        if com_pfx:
429            # do some cleanup and sanity checking on common prefix
430            if com_pfx[-1] == ".":
431                # prefix matches all but file extension: ok
432                # back up one to change 'foo.cc -> o' to 'foo.cc -> .o'
433                com_pfx = com_pfx[0:-1]
434            elif com_pfx[-1] == "/":
435                # common prefix is directory path: OK
436                pass
437            else:
438                src0_len = len(srcs[0])
439                tgt0_len = len(tgts[0])
440                if src0_len == com_pfx_len:
441                    # source is a substring of target, OK
442                    pass
443                elif tgt0_len == com_pfx_len:
444                    # target is a substring of source, need to back up to
445                    # avoid empty string on RHS of arrow
446                    sep_idx = com_pfx.rfind(".")
447                    if sep_idx != -1:
448                        com_pfx = com_pfx[0:sep_idx]
449                    else:
450                        com_pfx = ''
451                elif src0_len > com_pfx_len and srcs[0][com_pfx_len] == ".":
452                    # still splitting at file extension: ok
453                    pass
454                else:
455                    # probably a fluke; ignore it
456                    com_pfx = ''
457        # recalculate length in case com_pfx was modified
458        com_pfx_len = len(com_pfx)
459        def fmt(files):
460            f = map(lambda s: s[com_pfx_len:], files)
461            return ', '.join(f)
462        return self.format % (com_pfx, fmt(srcs), fmt(tgts))
463
464Export('Transform')
465
466
467if GetOption('verbose'):
468    def MakeAction(action, string, *args, **kwargs):
469        return Action(action, *args, **kwargs)
470else:
471    MakeAction = Action
472    main['CCCOMSTR']        = Transform("CC")
473    main['CXXCOMSTR']       = Transform("CXX")
474    main['ASCOMSTR']        = Transform("AS")
475    main['SWIGCOMSTR']      = Transform("SWIG")
476    main['ARCOMSTR']        = Transform("AR", 0)
477    main['LINKCOMSTR']      = Transform("LINK", 0)
478    main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
479    main['M4COMSTR']        = Transform("M4")
480    main['SHCCCOMSTR']      = Transform("SHCC")
481    main['SHCXXCOMSTR']     = Transform("SHCXX")
482Export('MakeAction')
483
484CXX_version = readCommand([main['CXX'],'--version'], exception=False)
485CXX_V = readCommand([main['CXX'],'-V'], exception=False)
486
487main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
488main['SUNCC'] = CXX_V and CXX_V.find('Sun C++') >= 0
489main['ICC'] = CXX_V and CXX_V.find('Intel') >= 0
490main['CLANG'] = CXX_V and CXX_V.find('clang') >= 0
491if main['GCC'] + main['SUNCC'] + main['ICC'] + main['CLANG'] > 1:
492    print 'Error: How can we have two at the same time?'
493    Exit(1)
494
495# Set up default C++ compiler flags
496if main['GCC']:
497    main.Append(CCFLAGS=['-pipe'])
498    main.Append(CCFLAGS=['-fno-strict-aliasing'])
499    main.Append(CCFLAGS=['-Wall', '-Wno-sign-compare', '-Wundef'])
500    main.Append(CXXFLAGS=['-Wno-deprecated'])
501    # Read the GCC version to check for versions with bugs
502    # Note CCVERSION doesn't work here because it is run with the CC
503    # before we override it from the command line
504    gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
505    main['GCC_VERSION'] = gcc_version
506    if not compareVersions(gcc_version, '4.4.1') or \
507       not compareVersions(gcc_version, '4.4.2'):
508        print 'Info: Tree vectorizer in GCC 4.4.1 & 4.4.2 is buggy, disabling.'
509        main.Append(CCFLAGS=['-fno-tree-vectorize'])
510elif main['ICC']:
511    pass #Fix me... add warning flags once we clean up icc warnings
512elif main['SUNCC']:
513    main.Append(CCFLAGS=['-Qoption ccfe'])
514    main.Append(CCFLAGS=['-features=gcc'])
515    main.Append(CCFLAGS=['-features=extensions'])
516    main.Append(CCFLAGS=['-library=stlport4'])
517    main.Append(CCFLAGS=['-xar'])
518    #main.Append(CCFLAGS=['-instances=semiexplicit'])
519elif main['CLANG']:
520    clang_version_re = re.compile(".* version (\d+\.\d+)")
521    clang_version_match = clang_version_re.match(CXX_version)
522    if (clang_version_match):
523        clang_version = clang_version_match.groups()[0]
524        if compareVersions(clang_version, "2.9") < 0:
525            print 'Error: clang version 2.9 or newer required.'
526            print '       Installed version:', clang_version
527            Exit(1)
528    else:
529        print 'Error: Unable to determine clang version.'
530        Exit(1)
531
532    main.Append(CCFLAGS=['-pipe'])
533    main.Append(CCFLAGS=['-fno-strict-aliasing'])
534    main.Append(CCFLAGS=['-Wall', '-Wno-sign-compare', '-Wundef'])
535    main.Append(CCFLAGS=['-Wno-tautological-compare'])
536    main.Append(CCFLAGS=['-Wno-self-assign'])
537else:
538    print 'Error: Don\'t know what compiler options to use for your compiler.'
539    print '       Please fix SConstruct and src/SConscript and try again.'
540    Exit(1)
541
542# Set up common yacc/bison flags (needed for Ruby)
543main['YACCFLAGS'] = '-d'
544main['YACCHXXFILESUFFIX'] = '.hh'
545
546# Do this after we save setting back, or else we'll tack on an
547# extra 'qdo' every time we run scons.
548if main['BATCH']:
549    main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
550    main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
551    main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
552    main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
553    main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
554
555if sys.platform == 'cygwin':
556    # cygwin has some header file issues...
557    main.Append(CCFLAGS=["-Wno-uninitialized"])
558
559# Check for SWIG
560if not main.has_key('SWIG'):
561    print 'Error: SWIG utility not found.'
562    print '       Please install (see http://www.swig.org) and retry.'
563    Exit(1)
564
565# Check for appropriate SWIG version
566swig_version = readCommand(('swig', '-version'), exception='').split()
567# First 3 words should be "SWIG Version x.y.z"
568if len(swig_version) < 3 or \
569        swig_version[0] != 'SWIG' or swig_version[1] != 'Version':
570    print 'Error determining SWIG version.'
571    Exit(1)
572
573min_swig_version = '1.3.28'
574if compareVersions(swig_version[2], min_swig_version) < 0:
575    print 'Error: SWIG version', min_swig_version, 'or newer required.'
576    print '       Installed version:', swig_version[2]
577    Exit(1)
578
579# Set up SWIG flags & scanner
580swig_flags=Split('-c++ -python -modern -templatereduce $_CPPINCFLAGS')
581main.Append(SWIGFLAGS=swig_flags)
582
583# filter out all existing swig scanners, they mess up the dependency
584# stuff for some reason
585scanners = []
586for scanner in main['SCANNERS']:
587    skeys = scanner.skeys
588    if skeys == '.i':
589        continue
590
591    if isinstance(skeys, (list, tuple)) and '.i' in skeys:
592        continue
593
594    scanners.append(scanner)
595
596# add the new swig scanner that we like better
597from SCons.Scanner import ClassicCPP as CPPScanner
598swig_inc_re = '^[ \t]*[%,#][ \t]*(?:include|import)[ \t]*(<|")([^>"]+)(>|")'
599scanners.append(CPPScanner("SwigScan", [ ".i" ], "CPPPATH", swig_inc_re))
600
601# replace the scanners list that has what we want
602main['SCANNERS'] = scanners
603
604# Add a custom Check function to the Configure context so that we can
605# figure out if the compiler adds leading underscores to global
606# variables.  This is needed for the autogenerated asm files that we
607# use for embedding the python code.
608def CheckLeading(context):
609    context.Message("Checking for leading underscore in global variables...")
610    # 1) Define a global variable called x from asm so the C compiler
611    #    won't change the symbol at all.
612    # 2) Declare that variable.
613    # 3) Use the variable
614    #
615    # If the compiler prepends an underscore, this will successfully
616    # link because the external symbol 'x' will be called '_x' which
617    # was defined by the asm statement.  If the compiler does not
618    # prepend an underscore, this will not successfully link because
619    # '_x' will have been defined by assembly, while the C portion of
620    # the code will be trying to use 'x'
621    ret = context.TryLink('''
622        asm(".globl _x; _x: .byte 0");
623        extern int x;
624        int main() { return x; }
625        ''', extension=".c")
626    context.env.Append(LEADING_UNDERSCORE=ret)
627    context.Result(ret)
628    return ret
629
630# Platform-specific configuration.  Note again that we assume that all
631# builds under a given build root run on the same host platform.
632conf = Configure(main,
633                 conf_dir = joinpath(build_root, '.scons_config'),
634                 log_file = joinpath(build_root, 'scons_config.log'),
635                 custom_tests = { 'CheckLeading' : CheckLeading })
636
637# Check for leading underscores.  Don't really need to worry either
638# way so don't need to check the return code.
639conf.CheckLeading()
640
641# Check if we should compile a 64 bit binary on Mac OS X/Darwin
642try:
643    import platform
644    uname = platform.uname()
645    if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
646        if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
647            main.Append(CCFLAGS=['-arch', 'x86_64'])
648            main.Append(CFLAGS=['-arch', 'x86_64'])
649            main.Append(LINKFLAGS=['-arch', 'x86_64'])
650            main.Append(ASFLAGS=['-arch', 'x86_64'])
651except:
652    pass
653
654# Recent versions of scons substitute a "Null" object for Configure()
655# when configuration isn't necessary, e.g., if the "--help" option is
656# present.  Unfortuantely this Null object always returns false,
657# breaking all our configuration checks.  We replace it with our own
658# more optimistic null object that returns True instead.
659if not conf:
660    def NullCheck(*args, **kwargs):
661        return True
662
663    class NullConf:
664        def __init__(self, env):
665            self.env = env
666        def Finish(self):
667            return self.env
668        def __getattr__(self, mname):
669            return NullCheck
670
671    conf = NullConf(main)
672
673# Find Python include and library directories for embedding the
674# interpreter.  For consistency, we will use the same Python
675# installation used to run scons (and thus this script).  If you want
676# to link in an alternate version, see above for instructions on how
677# to invoke scons with a different copy of the Python interpreter.
678from distutils import sysconfig
679
680py_getvar = sysconfig.get_config_var
681
682py_debug = getattr(sys, 'pydebug', False)
683py_version = 'python' + py_getvar('VERSION') + (py_debug and "_d" or "")
684
685py_general_include = sysconfig.get_python_inc()
686py_platform_include = sysconfig.get_python_inc(plat_specific=True)
687py_includes = [ py_general_include ]
688if py_platform_include != py_general_include:
689    py_includes.append(py_platform_include)
690
691py_lib_path = [ py_getvar('LIBDIR') ]
692# add the prefix/lib/pythonX.Y/config dir, but only if there is no
693# shared library in prefix/lib/.
694if not py_getvar('Py_ENABLE_SHARED'):
695    py_lib_path.append(py_getvar('LIBPL'))
696
697py_libs = []
698for lib in py_getvar('LIBS').split() + py_getvar('SYSLIBS').split():
699    if not lib.startswith('-l'):
700        # Python requires some special flags to link (e.g. -framework
701        # common on OS X systems), assume appending preserves order
702        main.Append(LINKFLAGS=[lib])
703    else:
704        lib = lib[2:]
705        if lib not in py_libs:
706            py_libs.append(lib)
707py_libs.append(py_version)
708
709main.Append(CPPPATH=py_includes)
710main.Append(LIBPATH=py_lib_path)
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
717
718# verify that this stuff works
719if not conf.CheckHeader('Python.h', '<>'):
720    print "Error: can't find Python.h header in", py_includes
721    Exit(1)
722
723for lib in py_libs:
724    if not conf.CheckLib(lib):
725        print "Error: can't find library %s required by python" % lib
726        Exit(1)
727
728# On Solaris you need to use libsocket for socket ops
729if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
730   if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
731       print "Can't find library with socket calls (e.g. accept())"
732       Exit(1)
733
734# Check for zlib.  If the check passes, libz will be automatically
735# added to the LIBS environment variable.
736if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
737    print 'Error: did not find needed zlib compression library '\
738          'and/or zlib.h header file.'
739    print '       Please install zlib and try again.'
740    Exit(1)
741
742# Check for librt.
743have_posix_clock = \
744    conf.CheckLibWithHeader(None, 'time.h', 'C',
745                            'clock_nanosleep(0,0,NULL,NULL);') or \
746    conf.CheckLibWithHeader('rt', 'time.h', 'C',
747                            'clock_nanosleep(0,0,NULL,NULL);')
748
749if not have_posix_clock:
750    print "Can't find library for POSIX clocks."
751
752# Check for <fenv.h> (C99 FP environment control)
753have_fenv = conf.CheckHeader('fenv.h', '<>')
754if not have_fenv:
755    print "Warning: Header file <fenv.h> not found."
756    print "         This host has no IEEE FP rounding mode control."
757
758######################################################################
759#
760# Finish the configuration
761#
762main = conf.Finish()
763
764######################################################################
765#
766# Collect all non-global variables
767#
768
769# Define the universe of supported ISAs
770all_isa_list = [ ]
771Export('all_isa_list')
772
773class CpuModel(object):
774    '''The CpuModel class encapsulates everything the ISA parser needs to
775    know about a particular CPU model.'''
776
777    # Dict of available CPU model objects.  Accessible as CpuModel.dict.
778    dict = {}
779    list = []
780    defaults = []
781
782    # Constructor.  Automatically adds models to CpuModel.dict.
783    def __init__(self, name, filename, includes, strings, default=False):
784        self.name = name           # name of model
785        self.filename = filename   # filename for output exec code
786        self.includes = includes   # include files needed in exec file
787        # The 'strings' dict holds all the per-CPU symbols we can
788        # substitute into templates etc.
789        self.strings = strings
790
791        # This cpu is enabled by default
792        self.default = default
793
794        # Add self to dict
795        if name in CpuModel.dict:
796            raise AttributeError, "CpuModel '%s' already registered" % name
797        CpuModel.dict[name] = self
798        CpuModel.list.append(name)
799
800Export('CpuModel')
801
802# Sticky variables get saved in the variables file so they persist from
803# one invocation to the next (unless overridden, in which case the new
804# value becomes sticky).
805sticky_vars = Variables(args=ARGUMENTS)
806Export('sticky_vars')
807
808# Sticky variables that should be exported
809export_vars = []
810Export('export_vars')
811
812# Walk the tree and execute all SConsopts scripts that wil add to the
813# above variables
814if not GetOption('verbose'):
815    print "Reading SConsopts"
816for bdir in [ base_dir ] + extras_dir_list:
817    if not isdir(bdir):
818        print "Error: directory '%s' does not exist" % bdir
819        Exit(1)
820    for root, dirs, files in os.walk(bdir):
821        if 'SConsopts' in files:
822            if GetOption('verbose'):
823                print "Reading", joinpath(root, 'SConsopts')
824            SConscript(joinpath(root, 'SConsopts'))
825
826all_isa_list.sort()
827
828sticky_vars.AddVariables(
829    EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
830    ListVariable('CPU_MODELS', 'CPU models',
831                 sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
832                 sorted(CpuModel.list)),
833    BoolVariable('NO_FAST_ALLOC', 'Disable fast object allocator', False),
834    BoolVariable('FORCE_FAST_ALLOC',
835                 'Enable fast object allocator, even for gem5.debug', False),
836    BoolVariable('FAST_ALLOC_STATS', 'Enable fast object allocator statistics',
837                 False),
838    BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
839                 False),
840    BoolVariable('SS_COMPATIBLE_FP',
841                 'Make floating-point results compatible with SimpleScalar',
842                 False),
843    BoolVariable('USE_SSE2',
844                 'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
845                 False),
846    BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
847    BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
848    BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability', False),
849    )
850
851# These variables get exported to #defines in config/*.hh (see src/SConscript).
852export_vars += ['USE_FENV', 'NO_FAST_ALLOC', 'FORCE_FAST_ALLOC',
853                'FAST_ALLOC_STATS', 'SS_COMPATIBLE_FP',
854                'TARGET_ISA', 'CP_ANNOTATE', 'USE_POSIX_CLOCK' ]
855
856###################################################
857#
858# Define a SCons builder for configuration flag headers.
859#
860###################################################
861
862# This function generates a config header file that #defines the
863# variable symbol to the current variable setting (0 or 1).  The source
864# operands are the name of the variable and a Value node containing the
865# value of the variable.
866def build_config_file(target, source, env):
867    (variable, value) = [s.get_contents() for s in source]
868    f = file(str(target[0]), 'w')
869    print >> f, '#define', variable, value
870    f.close()
871    return None
872
873# Combine the two functions into a scons Action object.
874config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
875
876# The emitter munges the source & target node lists to reflect what
877# we're really doing.
878def config_emitter(target, source, env):
879    # extract variable name from Builder arg
880    variable = str(target[0])
881    # True target is config header file
882    target = joinpath('config', variable.lower() + '.hh')
883    val = env[variable]
884    if isinstance(val, bool):
885        # Force value to 0/1
886        val = int(val)
887    elif isinstance(val, str):
888        val = '"' + val + '"'
889
890    # Sources are variable name & value (packaged in SCons Value nodes)
891    return ([target], [Value(variable), Value(val)])
892
893config_builder = Builder(emitter = config_emitter, action = config_action)
894
895main.Append(BUILDERS = { 'ConfigFile' : config_builder })
896
897# libelf build is shared across all configs in the build root.
898main.SConscript('ext/libelf/SConscript',
899                variant_dir = joinpath(build_root, 'libelf'))
900
901# gzstream build is shared across all configs in the build root.
902main.SConscript('ext/gzstream/SConscript',
903                variant_dir = joinpath(build_root, 'gzstream'))
904
905###################################################
906#
907# This function is used to set up a directory with switching headers
908#
909###################################################
910
911main['ALL_ISA_LIST'] = all_isa_list
912def make_switching_dir(dname, switch_headers, env):
913    # Generate the header.  target[0] is the full path of the output
914    # header to generate.  'source' is a dummy variable, since we get the
915    # list of ISAs from env['ALL_ISA_LIST'].
916    def gen_switch_hdr(target, source, env):
917        fname = str(target[0])
918        f = open(fname, 'w')
919        isa = env['TARGET_ISA'].lower()
920        print >>f, '#include "%s/%s/%s"' % (dname, isa, basename(fname))
921        f.close()
922
923    # Build SCons Action object. 'varlist' specifies env vars that this
924    # action depends on; when env['ALL_ISA_LIST'] changes these actions
925    # should get re-executed.
926    switch_hdr_action = MakeAction(gen_switch_hdr,
927                          Transform("GENERATE"), varlist=['ALL_ISA_LIST'])
928
929    # Instantiate actions for each header
930    for hdr in switch_headers:
931        env.Command(hdr, [], switch_hdr_action)
932Export('make_switching_dir')
933
934###################################################
935#
936# Define build environments for selected configurations.
937#
938###################################################
939
940for variant_path in variant_paths:
941    print "Building in", variant_path
942
943    # Make a copy of the build-root environment to use for this config.
944    env = main.Clone()
945    env['BUILDDIR'] = variant_path
946
947    # variant_dir is the tail component of build path, and is used to
948    # determine the build parameters (e.g., 'ALPHA_SE')
949    (build_root, variant_dir) = splitpath(variant_path)
950
951    # Set env variables according to the build directory config.
952    sticky_vars.files = []
953    # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
954    # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
955    # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
956    current_vars_file = joinpath(build_root, 'variables', variant_dir)
957    if isfile(current_vars_file):
958        sticky_vars.files.append(current_vars_file)
959        print "Using saved variables file %s" % current_vars_file
960    else:
961        # Build dir-specific variables file doesn't exist.
962
963        # Make sure the directory is there so we can create it later
964        opt_dir = dirname(current_vars_file)
965        if not isdir(opt_dir):
966            mkdir(opt_dir)
967
968        # Get default build variables from source tree.  Variables are
969        # normally determined by name of $VARIANT_DIR, but can be
970        # overridden by '--default=' arg on command line.
971        default = GetOption('default')
972        opts_dir = joinpath(main.root.abspath, 'build_opts')
973        if default:
974            default_vars_files = [joinpath(build_root, 'variables', default),
975                                  joinpath(opts_dir, default)]
976        else:
977            default_vars_files = [joinpath(opts_dir, variant_dir)]
978        existing_files = filter(isfile, default_vars_files)
979        if existing_files:
980            default_vars_file = existing_files[0]
981            sticky_vars.files.append(default_vars_file)
982            print "Variables file %s not found,\n  using defaults in %s" \
983                  % (current_vars_file, default_vars_file)
984        else:
985            print "Error: cannot find variables file %s or " \
986                  "default file(s) %s" \
987                  % (current_vars_file, ' or '.join(default_vars_files))
988            Exit(1)
989
990    # Apply current variable settings to env
991    sticky_vars.Update(env)
992
993    help_texts["local_vars"] += \
994        "Build variables for %s:\n" % variant_dir \
995                 + sticky_vars.GenerateHelpText(env)
996
997    # Process variable settings.
998
999    if not have_fenv and env['USE_FENV']:
1000        print "Warning: <fenv.h> not available; " \
1001              "forcing USE_FENV to False in", variant_dir + "."
1002        env['USE_FENV'] = False
1003
1004    if not env['USE_FENV']:
1005        print "Warning: No IEEE FP rounding mode control in", variant_dir + "."
1006        print "         FP results may deviate slightly from other platforms."
1007
1008    if env['EFENCE']:
1009        env.Append(LIBS=['efence'])
1010
1011    # Save sticky variable settings back to current variables file
1012    sticky_vars.Save(current_vars_file, env)
1013
1014    if env['USE_SSE2']:
1015        env.Append(CCFLAGS=['-msse2'])
1016
1017    # The src/SConscript file sets up the build rules in 'env' according
1018    # to the configured variables.  It returns a list of environments,
1019    # one for each variant build (debug, opt, etc.)
1020    envList = SConscript('src/SConscript', variant_dir = variant_path,
1021                         exports = 'env')
1022
1023    # Set up the regression tests for each build.
1024    for e in envList:
1025        SConscript('tests/SConscript',
1026                   variant_dir = joinpath(variant_path, 'tests', e.Label),
1027                   exports = { 'env' : e }, duplicate = False)
1028
1029# base help text
1030Help('''
1031Usage: scons [scons options] [build variables] [target(s)]
1032
1033Extra scons options:
1034%(options)s
1035
1036Global build variables:
1037%(global_vars)s
1038
1039%(local_vars)s
1040''' % help_texts)
1041