SConstruct revision 8960
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('--update-ref', dest='update_ref', action='store_true',
169               help='Update test reference outputs')
170AddLocalOption('--verbose', dest='verbose', action='store_true',
171               help='Print full tool command lines')
172
173termcap = get_termcap(GetOption('use_colors'))
174
175########################################################################
176#
177# Set up the main build environment.
178#
179########################################################################
180use_vars = set([ 'AS', 'AR', 'CC', 'CXX', 'HOME', 'LD_LIBRARY_PATH', 'PATH',
181                 'PYTHONPATH', 'RANLIB' ])
182
183use_env = {}
184for key,val in os.environ.iteritems():
185    if key in use_vars or key.startswith("M5"):
186        use_env[key] = val
187
188main = Environment(ENV=use_env)
189main.Decider('MD5-timestamp')
190main.root = Dir(".")         # The current directory (where this file lives).
191main.srcdir = Dir("src")     # The source directory
192
193# add useful python code PYTHONPATH so it can be used by subprocesses
194# as well
195main.AppendENVPath('PYTHONPATH', extra_python_paths)
196
197########################################################################
198#
199# Mercurial Stuff.
200#
201# If the gem5 directory is a mercurial repository, we should do some
202# extra things.
203#
204########################################################################
205
206hgdir = main.root.Dir(".hg")
207
208mercurial_style_message = """
209You're missing the gem5 style hook, which automatically checks your code
210against the gem5 style rules on hg commit and qrefresh commands.  This
211script will now install the hook in your .hg/hgrc file.
212Press enter to continue, or ctrl-c to abort: """
213
214mercurial_style_hook = """
215# The following lines were automatically added by gem5/SConstruct
216# to provide the gem5 style-checking hooks
217[extensions]
218style = %s/util/style.py
219
220[hooks]
221pretxncommit.style = python:style.check_style
222pre-qrefresh.style = python:style.check_style
223# End of SConstruct additions
224
225""" % (main.root.abspath)
226
227mercurial_lib_not_found = """
228Mercurial libraries cannot be found, ignoring style hook.  If
229you are a gem5 developer, please fix this and run the style
230hook. It is important.
231"""
232
233# Check for style hook and prompt for installation if it's not there.
234# Skip this if --ignore-style was specified, there's no .hg dir to
235# install a hook in, or there's no interactive terminal to prompt.
236if not GetOption('ignore_style') and hgdir.exists() and sys.stdin.isatty():
237    style_hook = True
238    try:
239        from mercurial import ui
240        ui = ui.ui()
241        ui.readconfig(hgdir.File('hgrc').abspath)
242        style_hook = ui.config('hooks', 'pretxncommit.style', None) and \
243                     ui.config('hooks', 'pre-qrefresh.style', None)
244    except ImportError:
245        print mercurial_lib_not_found
246
247    if not style_hook:
248        print mercurial_style_message,
249        # continue unless user does ctrl-c/ctrl-d etc.
250        try:
251            raw_input()
252        except:
253            print "Input exception, exiting scons.\n"
254            sys.exit(1)
255        hgrc_path = '%s/.hg/hgrc' % main.root.abspath
256        print "Adding style hook to", hgrc_path, "\n"
257        try:
258            hgrc = open(hgrc_path, 'a')
259            hgrc.write(mercurial_style_hook)
260            hgrc.close()
261        except:
262            print "Error updating", hgrc_path
263            sys.exit(1)
264
265
266###################################################
267#
268# Figure out which configurations to set up based on the path(s) of
269# the target(s).
270#
271###################################################
272
273# Find default configuration & binary.
274Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))
275
276# helper function: find last occurrence of element in list
277def rfind(l, elt, offs = -1):
278    for i in range(len(l)+offs, 0, -1):
279        if l[i] == elt:
280            return i
281    raise ValueError, "element not found"
282
283# Take a list of paths (or SCons Nodes) and return a list with all
284# paths made absolute and ~-expanded.  Paths will be interpreted
285# relative to the launch directory unless a different root is provided
286def makePathListAbsolute(path_list, root=GetLaunchDir()):
287    return [abspath(joinpath(root, expanduser(str(p))))
288            for p in path_list]
289
290# Each target must have 'build' in the interior of the path; the
291# directory below this will determine the build parameters.  For
292# example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
293# recognize that ALPHA_SE specifies the configuration because it
294# follow 'build' in the build path.
295
296# The funky assignment to "[:]" is needed to replace the list contents
297# in place rather than reassign the symbol to a new list, which
298# doesn't work (obviously!).
299BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
300
301# Generate a list of the unique build roots and configs that the
302# collected targets reference.
303variant_paths = []
304build_root = None
305for t in BUILD_TARGETS:
306    path_dirs = t.split('/')
307    try:
308        build_top = rfind(path_dirs, 'build', -2)
309    except:
310        print "Error: no non-leaf 'build' dir found on target path", t
311        Exit(1)
312    this_build_root = joinpath('/',*path_dirs[:build_top+1])
313    if not build_root:
314        build_root = this_build_root
315    else:
316        if this_build_root != build_root:
317            print "Error: build targets not under same build root\n"\
318                  "  %s\n  %s" % (build_root, this_build_root)
319            Exit(1)
320    variant_path = joinpath('/',*path_dirs[:build_top+2])
321    if variant_path not in variant_paths:
322        variant_paths.append(variant_path)
323
324# Make sure build_root exists (might not if this is the first build there)
325if not isdir(build_root):
326    mkdir(build_root)
327main['BUILDROOT'] = build_root
328
329Export('main')
330
331main.SConsignFile(joinpath(build_root, "sconsign"))
332
333# Default duplicate option is to use hard links, but this messes up
334# when you use emacs to edit a file in the target dir, as emacs moves
335# file to file~ then copies to file, breaking the link.  Symbolic
336# (soft) links work better.
337main.SetOption('duplicate', 'soft-copy')
338
339#
340# Set up global sticky variables... these are common to an entire build
341# tree (not specific to a particular build like ALPHA_SE)
342#
343
344global_vars_file = joinpath(build_root, 'variables.global')
345
346global_vars = Variables(global_vars_file, args=ARGUMENTS)
347
348global_vars.AddVariables(
349    ('CC', 'C compiler', environ.get('CC', main['CC'])),
350    ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
351    ('BATCH', 'Use batch pool for build and tests', False),
352    ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
353    ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
354    ('EXTRAS', 'Add extra directories to the compilation', '')
355    )
356
357# Update main environment with values from ARGUMENTS & global_vars_file
358global_vars.Update(main)
359help_texts["global_vars"] += global_vars.GenerateHelpText(main)
360
361# Save sticky variable settings back to current variables file
362global_vars.Save(global_vars_file, main)
363
364# Parse EXTRAS variable to build list of all directories where we're
365# look for sources etc.  This list is exported as extras_dir_list.
366base_dir = main.srcdir.abspath
367if main['EXTRAS']:
368    extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
369else:
370    extras_dir_list = []
371
372Export('base_dir')
373Export('extras_dir_list')
374
375# the ext directory should be on the #includes path
376main.Append(CPPPATH=[Dir('ext')])
377
378def strip_build_path(path, env):
379    path = str(path)
380    variant_base = env['BUILDROOT'] + os.path.sep
381    if path.startswith(variant_base):
382        path = path[len(variant_base):]
383    elif path.startswith('build/'):
384        path = path[6:]
385    return path
386
387# Generate a string of the form:
388#   common/path/prefix/src1, src2 -> tgt1, tgt2
389# to print while building.
390class Transform(object):
391    # all specific color settings should be here and nowhere else
392    tool_color = termcap.Normal
393    pfx_color = termcap.Yellow
394    srcs_color = termcap.Yellow + termcap.Bold
395    arrow_color = termcap.Blue + termcap.Bold
396    tgts_color = termcap.Yellow + termcap.Bold
397
398    def __init__(self, tool, max_sources=99):
399        self.format = self.tool_color + (" [%8s] " % tool) \
400                      + self.pfx_color + "%s" \
401                      + self.srcs_color + "%s" \
402                      + self.arrow_color + " -> " \
403                      + self.tgts_color + "%s" \
404                      + termcap.Normal
405        self.max_sources = max_sources
406
407    def __call__(self, target, source, env, for_signature=None):
408        # truncate source list according to max_sources param
409        source = source[0:self.max_sources]
410        def strip(f):
411            return strip_build_path(str(f), env)
412        if len(source) > 0:
413            srcs = map(strip, source)
414        else:
415            srcs = ['']
416        tgts = map(strip, target)
417        # surprisingly, os.path.commonprefix is a dumb char-by-char string
418        # operation that has nothing to do with paths.
419        com_pfx = os.path.commonprefix(srcs + tgts)
420        com_pfx_len = len(com_pfx)
421        if com_pfx:
422            # do some cleanup and sanity checking on common prefix
423            if com_pfx[-1] == ".":
424                # prefix matches all but file extension: ok
425                # back up one to change 'foo.cc -> o' to 'foo.cc -> .o'
426                com_pfx = com_pfx[0:-1]
427            elif com_pfx[-1] == "/":
428                # common prefix is directory path: OK
429                pass
430            else:
431                src0_len = len(srcs[0])
432                tgt0_len = len(tgts[0])
433                if src0_len == com_pfx_len:
434                    # source is a substring of target, OK
435                    pass
436                elif tgt0_len == com_pfx_len:
437                    # target is a substring of source, need to back up to
438                    # avoid empty string on RHS of arrow
439                    sep_idx = com_pfx.rfind(".")
440                    if sep_idx != -1:
441                        com_pfx = com_pfx[0:sep_idx]
442                    else:
443                        com_pfx = ''
444                elif src0_len > com_pfx_len and srcs[0][com_pfx_len] == ".":
445                    # still splitting at file extension: ok
446                    pass
447                else:
448                    # probably a fluke; ignore it
449                    com_pfx = ''
450        # recalculate length in case com_pfx was modified
451        com_pfx_len = len(com_pfx)
452        def fmt(files):
453            f = map(lambda s: s[com_pfx_len:], files)
454            return ', '.join(f)
455        return self.format % (com_pfx, fmt(srcs), fmt(tgts))
456
457Export('Transform')
458
459# enable the regression script to use the termcap
460main['TERMCAP'] = termcap
461
462if GetOption('verbose'):
463    def MakeAction(action, string, *args, **kwargs):
464        return Action(action, *args, **kwargs)
465else:
466    MakeAction = Action
467    main['CCCOMSTR']        = Transform("CC")
468    main['CXXCOMSTR']       = Transform("CXX")
469    main['ASCOMSTR']        = Transform("AS")
470    main['SWIGCOMSTR']      = Transform("SWIG")
471    main['ARCOMSTR']        = Transform("AR", 0)
472    main['LINKCOMSTR']      = Transform("LINK", 0)
473    main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
474    main['M4COMSTR']        = Transform("M4")
475    main['SHCCCOMSTR']      = Transform("SHCC")
476    main['SHCXXCOMSTR']     = Transform("SHCXX")
477Export('MakeAction')
478
479CXX_version = readCommand([main['CXX'],'--version'], exception=False)
480CXX_V = readCommand([main['CXX'],'-V'], exception=False)
481
482main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
483main['SUNCC'] = CXX_V and CXX_V.find('Sun C++') >= 0
484main['ICC'] = CXX_V and CXX_V.find('Intel') >= 0
485main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
486if main['GCC'] + main['SUNCC'] + main['ICC'] + main['CLANG'] > 1:
487    print 'Error: How can we have two at the same time?'
488    Exit(1)
489
490# Set up default C++ compiler flags
491if main['GCC']:
492    main.Append(CCFLAGS=['-pipe'])
493    main.Append(CCFLAGS=['-fno-strict-aliasing'])
494    main.Append(CCFLAGS=['-Wall', '-Wno-sign-compare', '-Wundef'])
495    # Read the GCC version to check for versions with bugs
496    # Note CCVERSION doesn't work here because it is run with the CC
497    # before we override it from the command line
498    gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
499    main['GCC_VERSION'] = gcc_version
500    if not compareVersions(gcc_version, '4.4.1') or \
501       not compareVersions(gcc_version, '4.4.2'):
502        print 'Info: Tree vectorizer in GCC 4.4.1 & 4.4.2 is buggy, disabling.'
503        main.Append(CCFLAGS=['-fno-tree-vectorize'])
504    if compareVersions(gcc_version, '4.6') >= 0:
505        main.Append(CXXFLAGS=['-std=c++0x'])
506elif main['ICC']:
507    pass #Fix me... add warning flags once we clean up icc warnings
508elif main['SUNCC']:
509    main.Append(CCFLAGS=['-Qoption ccfe'])
510    main.Append(CCFLAGS=['-features=gcc'])
511    main.Append(CCFLAGS=['-features=extensions'])
512    main.Append(CCFLAGS=['-library=stlport4'])
513    main.Append(CCFLAGS=['-xar'])
514    #main.Append(CCFLAGS=['-instances=semiexplicit'])
515elif main['CLANG']:
516    clang_version_re = re.compile(".* version (\d+\.\d+)")
517    clang_version_match = clang_version_re.match(CXX_version)
518    if (clang_version_match):
519        clang_version = clang_version_match.groups()[0]
520        if compareVersions(clang_version, "2.9") < 0:
521            print 'Error: clang version 2.9 or newer required.'
522            print '       Installed version:', clang_version
523            Exit(1)
524    else:
525        print 'Error: Unable to determine clang version.'
526        Exit(1)
527
528    main.Append(CCFLAGS=['-pipe'])
529    main.Append(CCFLAGS=['-fno-strict-aliasing'])
530    main.Append(CCFLAGS=['-Wall', '-Wno-sign-compare', '-Wundef'])
531    main.Append(CCFLAGS=['-Wno-tautological-compare'])
532    main.Append(CCFLAGS=['-Wno-self-assign'])
533    # Ruby makes frequent use of extraneous parantheses in the printing
534    # of if-statements
535    main.Append(CCFLAGS=['-Wno-parentheses'])
536
537    if compareVersions(clang_version, "3") >= 0:
538        main.Append(CXXFLAGS=['-std=c++0x'])
539else:
540    print 'Error: Don\'t know what compiler options to use for your compiler.'
541    print '       Please fix SConstruct and src/SConscript and try again.'
542    Exit(1)
543
544# Set up common yacc/bison flags (needed for Ruby)
545main['YACCFLAGS'] = '-d'
546main['YACCHXXFILESUFFIX'] = '.hh'
547
548# Do this after we save setting back, or else we'll tack on an
549# extra 'qdo' every time we run scons.
550if main['BATCH']:
551    main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
552    main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
553    main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
554    main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
555    main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
556
557if sys.platform == 'cygwin':
558    # cygwin has some header file issues...
559    main.Append(CCFLAGS=["-Wno-uninitialized"])
560
561# Check for SWIG
562if not main.has_key('SWIG'):
563    print 'Error: SWIG utility not found.'
564    print '       Please install (see http://www.swig.org) and retry.'
565    Exit(1)
566
567# Check for appropriate SWIG version
568swig_version = readCommand(('swig', '-version'), exception='').split()
569# First 3 words should be "SWIG Version x.y.z"
570if len(swig_version) < 3 or \
571        swig_version[0] != 'SWIG' or swig_version[1] != 'Version':
572    print 'Error determining SWIG version.'
573    Exit(1)
574
575min_swig_version = '1.3.34'
576if compareVersions(swig_version[2], min_swig_version) < 0:
577    print 'Error: SWIG version', min_swig_version, 'or newer required.'
578    print '       Installed version:', swig_version[2]
579    Exit(1)
580
581# Set up SWIG flags & scanner
582swig_flags=Split('-c++ -python -modern -templatereduce $_CPPINCFLAGS')
583main.Append(SWIGFLAGS=swig_flags)
584
585# filter out all existing swig scanners, they mess up the dependency
586# stuff for some reason
587scanners = []
588for scanner in main['SCANNERS']:
589    skeys = scanner.skeys
590    if skeys == '.i':
591        continue
592
593    if isinstance(skeys, (list, tuple)) and '.i' in skeys:
594        continue
595
596    scanners.append(scanner)
597
598# add the new swig scanner that we like better
599from SCons.Scanner import ClassicCPP as CPPScanner
600swig_inc_re = '^[ \t]*[%,#][ \t]*(?:include|import)[ \t]*(<|")([^>"]+)(>|")'
601scanners.append(CPPScanner("SwigScan", [ ".i" ], "CPPPATH", swig_inc_re))
602
603# replace the scanners list that has what we want
604main['SCANNERS'] = scanners
605
606# Add a custom Check function to the Configure context so that we can
607# figure out if the compiler adds leading underscores to global
608# variables.  This is needed for the autogenerated asm files that we
609# use for embedding the python code.
610def CheckLeading(context):
611    context.Message("Checking for leading underscore in global variables...")
612    # 1) Define a global variable called x from asm so the C compiler
613    #    won't change the symbol at all.
614    # 2) Declare that variable.
615    # 3) Use the variable
616    #
617    # If the compiler prepends an underscore, this will successfully
618    # link because the external symbol 'x' will be called '_x' which
619    # was defined by the asm statement.  If the compiler does not
620    # prepend an underscore, this will not successfully link because
621    # '_x' will have been defined by assembly, while the C portion of
622    # the code will be trying to use 'x'
623    ret = context.TryLink('''
624        asm(".globl _x; _x: .byte 0");
625        extern int x;
626        int main() { return x; }
627        ''', extension=".c")
628    context.env.Append(LEADING_UNDERSCORE=ret)
629    context.Result(ret)
630    return ret
631
632# Platform-specific configuration.  Note again that we assume that all
633# builds under a given build root run on the same host platform.
634conf = Configure(main,
635                 conf_dir = joinpath(build_root, '.scons_config'),
636                 log_file = joinpath(build_root, 'scons_config.log'),
637                 custom_tests = { 'CheckLeading' : CheckLeading })
638
639# Check for leading underscores.  Don't really need to worry either
640# way so don't need to check the return code.
641conf.CheckLeading()
642
643# Check if we should compile a 64 bit binary on Mac OS X/Darwin
644try:
645    import platform
646    uname = platform.uname()
647    if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
648        if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
649            main.Append(CCFLAGS=['-arch', 'x86_64'])
650            main.Append(CFLAGS=['-arch', 'x86_64'])
651            main.Append(LINKFLAGS=['-arch', 'x86_64'])
652            main.Append(ASFLAGS=['-arch', 'x86_64'])
653except:
654    pass
655
656# Recent versions of scons substitute a "Null" object for Configure()
657# when configuration isn't necessary, e.g., if the "--help" option is
658# present.  Unfortuantely this Null object always returns false,
659# breaking all our configuration checks.  We replace it with our own
660# more optimistic null object that returns True instead.
661if not conf:
662    def NullCheck(*args, **kwargs):
663        return True
664
665    class NullConf:
666        def __init__(self, env):
667            self.env = env
668        def Finish(self):
669            return self.env
670        def __getattr__(self, mname):
671            return NullCheck
672
673    conf = NullConf(main)
674
675# Find Python include and library directories for embedding the
676# interpreter.  For consistency, we will use the same Python
677# installation used to run scons (and thus this script).  If you want
678# to link in an alternate version, see above for instructions on how
679# to invoke scons with a different copy of the Python interpreter.
680from distutils import sysconfig
681
682py_getvar = sysconfig.get_config_var
683
684py_debug = getattr(sys, 'pydebug', False)
685py_version = 'python' + py_getvar('VERSION') + (py_debug and "_d" or "")
686
687py_general_include = sysconfig.get_python_inc()
688py_platform_include = sysconfig.get_python_inc(plat_specific=True)
689py_includes = [ py_general_include ]
690if py_platform_include != py_general_include:
691    py_includes.append(py_platform_include)
692
693py_lib_path = [ py_getvar('LIBDIR') ]
694# add the prefix/lib/pythonX.Y/config dir, but only if there is no
695# shared library in prefix/lib/.
696if not py_getvar('Py_ENABLE_SHARED'):
697    py_lib_path.append(py_getvar('LIBPL'))
698
699py_libs = []
700for lib in py_getvar('LIBS').split() + py_getvar('SYSLIBS').split():
701    if not lib.startswith('-l'):
702        # Python requires some special flags to link (e.g. -framework
703        # common on OS X systems), assume appending preserves order
704        main.Append(LINKFLAGS=[lib])
705    else:
706        lib = lib[2:]
707        if lib not in py_libs:
708            py_libs.append(lib)
709py_libs.append(py_version)
710
711main.Append(CPPPATH=py_includes)
712main.Append(LIBPATH=py_lib_path)
713
714# Cache build files in the supplied directory.
715if main['M5_BUILD_CACHE']:
716    print 'Using build cache located at', main['M5_BUILD_CACHE']
717    CacheDir(main['M5_BUILD_CACHE'])
718
719
720# verify that this stuff works
721if not conf.CheckHeader('Python.h', '<>'):
722    print "Error: can't find Python.h header in", py_includes
723    Exit(1)
724
725for lib in py_libs:
726    if not conf.CheckLib(lib):
727        print "Error: can't find library %s required by python" % lib
728        Exit(1)
729
730# On Solaris you need to use libsocket for socket ops
731if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
732   if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
733       print "Can't find library with socket calls (e.g. accept())"
734       Exit(1)
735
736# Check for zlib.  If the check passes, libz will be automatically
737# added to the LIBS environment variable.
738if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
739    print 'Error: did not find needed zlib compression library '\
740          'and/or zlib.h header file.'
741    print '       Please install zlib and try again.'
742    Exit(1)
743
744# Check for librt.
745have_posix_clock = \
746    conf.CheckLibWithHeader(None, 'time.h', 'C',
747                            'clock_nanosleep(0,0,NULL,NULL);') or \
748    conf.CheckLibWithHeader('rt', 'time.h', 'C',
749                            'clock_nanosleep(0,0,NULL,NULL);')
750
751if not have_posix_clock:
752    print "Can't find library for POSIX clocks."
753
754# Check for <fenv.h> (C99 FP environment control)
755have_fenv = conf.CheckHeader('fenv.h', '<>')
756if not have_fenv:
757    print "Warning: Header file <fenv.h> not found."
758    print "         This host has no IEEE FP rounding mode control."
759
760######################################################################
761#
762# Finish the configuration
763#
764main = conf.Finish()
765
766######################################################################
767#
768# Collect all non-global variables
769#
770
771# Define the universe of supported ISAs
772all_isa_list = [ ]
773Export('all_isa_list')
774
775class CpuModel(object):
776    '''The CpuModel class encapsulates everything the ISA parser needs to
777    know about a particular CPU model.'''
778
779    # Dict of available CPU model objects.  Accessible as CpuModel.dict.
780    dict = {}
781    list = []
782    defaults = []
783
784    # Constructor.  Automatically adds models to CpuModel.dict.
785    def __init__(self, name, filename, includes, strings, default=False):
786        self.name = name           # name of model
787        self.filename = filename   # filename for output exec code
788        self.includes = includes   # include files needed in exec file
789        # The 'strings' dict holds all the per-CPU symbols we can
790        # substitute into templates etc.
791        self.strings = strings
792
793        # This cpu is enabled by default
794        self.default = default
795
796        # Add self to dict
797        if name in CpuModel.dict:
798            raise AttributeError, "CpuModel '%s' already registered" % name
799        CpuModel.dict[name] = self
800        CpuModel.list.append(name)
801
802Export('CpuModel')
803
804# Sticky variables get saved in the variables file so they persist from
805# one invocation to the next (unless overridden, in which case the new
806# value becomes sticky).
807sticky_vars = Variables(args=ARGUMENTS)
808Export('sticky_vars')
809
810# Sticky variables that should be exported
811export_vars = []
812Export('export_vars')
813
814# Walk the tree and execute all SConsopts scripts that wil add to the
815# above variables
816if not GetOption('verbose'):
817    print "Reading SConsopts"
818for bdir in [ base_dir ] + extras_dir_list:
819    if not isdir(bdir):
820        print "Error: directory '%s' does not exist" % bdir
821        Exit(1)
822    for root, dirs, files in os.walk(bdir):
823        if 'SConsopts' in files:
824            if GetOption('verbose'):
825                print "Reading", joinpath(root, 'SConsopts')
826            SConscript(joinpath(root, 'SConsopts'))
827
828all_isa_list.sort()
829
830sticky_vars.AddVariables(
831    EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
832    ListVariable('CPU_MODELS', 'CPU models',
833                 sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
834                 sorted(CpuModel.list)),
835    BoolVariable('NO_FAST_ALLOC', 'Disable fast object allocator', False),
836    BoolVariable('FORCE_FAST_ALLOC',
837                 'Enable fast object allocator, even for gem5.debug', False),
838    BoolVariable('FAST_ALLOC_STATS', 'Enable fast object allocator statistics',
839                 False),
840    BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
841                 False),
842    BoolVariable('SS_COMPATIBLE_FP',
843                 'Make floating-point results compatible with SimpleScalar',
844                 False),
845    BoolVariable('USE_SSE2',
846                 'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
847                 False),
848    BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
849    BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
850    BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability', False),
851    )
852
853# These variables get exported to #defines in config/*.hh (see src/SConscript).
854export_vars += ['USE_FENV', 'NO_FAST_ALLOC', 'FORCE_FAST_ALLOC',
855                'FAST_ALLOC_STATS', 'SS_COMPATIBLE_FP',
856                'TARGET_ISA', 'CP_ANNOTATE', 'USE_POSIX_CLOCK' ]
857
858###################################################
859#
860# Define a SCons builder for configuration flag headers.
861#
862###################################################
863
864# This function generates a config header file that #defines the
865# variable symbol to the current variable setting (0 or 1).  The source
866# operands are the name of the variable and a Value node containing the
867# value of the variable.
868def build_config_file(target, source, env):
869    (variable, value) = [s.get_contents() for s in source]
870    f = file(str(target[0]), 'w')
871    print >> f, '#define', variable, value
872    f.close()
873    return None
874
875# Combine the two functions into a scons Action object.
876config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
877
878# The emitter munges the source & target node lists to reflect what
879# we're really doing.
880def config_emitter(target, source, env):
881    # extract variable name from Builder arg
882    variable = str(target[0])
883    # True target is config header file
884    target = joinpath('config', variable.lower() + '.hh')
885    val = env[variable]
886    if isinstance(val, bool):
887        # Force value to 0/1
888        val = int(val)
889    elif isinstance(val, str):
890        val = '"' + val + '"'
891
892    # Sources are variable name & value (packaged in SCons Value nodes)
893    return ([target], [Value(variable), Value(val)])
894
895config_builder = Builder(emitter = config_emitter, action = config_action)
896
897main.Append(BUILDERS = { 'ConfigFile' : config_builder })
898
899# libelf build is shared across all configs in the build root.
900main.SConscript('ext/libelf/SConscript',
901                variant_dir = joinpath(build_root, 'libelf'))
902
903# gzstream build is shared across all configs in the build root.
904main.SConscript('ext/gzstream/SConscript',
905                variant_dir = joinpath(build_root, 'gzstream'))
906
907###################################################
908#
909# This function is used to set up a directory with switching headers
910#
911###################################################
912
913main['ALL_ISA_LIST'] = all_isa_list
914def make_switching_dir(dname, switch_headers, env):
915    # Generate the header.  target[0] is the full path of the output
916    # header to generate.  'source' is a dummy variable, since we get the
917    # list of ISAs from env['ALL_ISA_LIST'].
918    def gen_switch_hdr(target, source, env):
919        fname = str(target[0])
920        f = open(fname, 'w')
921        isa = env['TARGET_ISA'].lower()
922        print >>f, '#include "%s/%s/%s"' % (dname, isa, basename(fname))
923        f.close()
924
925    # Build SCons Action object. 'varlist' specifies env vars that this
926    # action depends on; when env['ALL_ISA_LIST'] changes these actions
927    # should get re-executed.
928    switch_hdr_action = MakeAction(gen_switch_hdr,
929                          Transform("GENERATE"), varlist=['ALL_ISA_LIST'])
930
931    # Instantiate actions for each header
932    for hdr in switch_headers:
933        env.Command(hdr, [], switch_hdr_action)
934Export('make_switching_dir')
935
936###################################################
937#
938# Define build environments for selected configurations.
939#
940###################################################
941
942for variant_path in variant_paths:
943    print "Building in", variant_path
944
945    # Make a copy of the build-root environment to use for this config.
946    env = main.Clone()
947    env['BUILDDIR'] = variant_path
948
949    # variant_dir is the tail component of build path, and is used to
950    # determine the build parameters (e.g., 'ALPHA_SE')
951    (build_root, variant_dir) = splitpath(variant_path)
952
953    # Set env variables according to the build directory config.
954    sticky_vars.files = []
955    # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
956    # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
957    # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
958    current_vars_file = joinpath(build_root, 'variables', variant_dir)
959    if isfile(current_vars_file):
960        sticky_vars.files.append(current_vars_file)
961        print "Using saved variables file %s" % current_vars_file
962    else:
963        # Build dir-specific variables file doesn't exist.
964
965        # Make sure the directory is there so we can create it later
966        opt_dir = dirname(current_vars_file)
967        if not isdir(opt_dir):
968            mkdir(opt_dir)
969
970        # Get default build variables from source tree.  Variables are
971        # normally determined by name of $VARIANT_DIR, but can be
972        # overridden by '--default=' arg on command line.
973        default = GetOption('default')
974        opts_dir = joinpath(main.root.abspath, 'build_opts')
975        if default:
976            default_vars_files = [joinpath(build_root, 'variables', default),
977                                  joinpath(opts_dir, default)]
978        else:
979            default_vars_files = [joinpath(opts_dir, variant_dir)]
980        existing_files = filter(isfile, default_vars_files)
981        if existing_files:
982            default_vars_file = existing_files[0]
983            sticky_vars.files.append(default_vars_file)
984            print "Variables file %s not found,\n  using defaults in %s" \
985                  % (current_vars_file, default_vars_file)
986        else:
987            print "Error: cannot find variables file %s or " \
988                  "default file(s) %s" \
989                  % (current_vars_file, ' or '.join(default_vars_files))
990            Exit(1)
991
992    # Apply current variable settings to env
993    sticky_vars.Update(env)
994
995    help_texts["local_vars"] += \
996        "Build variables for %s:\n" % variant_dir \
997                 + sticky_vars.GenerateHelpText(env)
998
999    # Process variable settings.
1000
1001    if not have_fenv and env['USE_FENV']:
1002        print "Warning: <fenv.h> not available; " \
1003              "forcing USE_FENV to False in", variant_dir + "."
1004        env['USE_FENV'] = False
1005
1006    if not env['USE_FENV']:
1007        print "Warning: No IEEE FP rounding mode control in", variant_dir + "."
1008        print "         FP results may deviate slightly from other platforms."
1009
1010    if env['EFENCE']:
1011        env.Append(LIBS=['efence'])
1012
1013    # Save sticky variable settings back to current variables file
1014    sticky_vars.Save(current_vars_file, env)
1015
1016    if env['USE_SSE2']:
1017        env.Append(CCFLAGS=['-msse2'])
1018
1019    # The src/SConscript file sets up the build rules in 'env' according
1020    # to the configured variables.  It returns a list of environments,
1021    # one for each variant build (debug, opt, etc.)
1022    envList = SConscript('src/SConscript', variant_dir = variant_path,
1023                         exports = 'env')
1024
1025    # Set up the regression tests for each build.
1026    for e in envList:
1027        SConscript('tests/SConscript',
1028                   variant_dir = joinpath(variant_path, 'tests', e.Label),
1029                   exports = { 'env' : e }, duplicate = False)
1030
1031# base help text
1032Help('''
1033Usage: scons [scons options] [build variables] [target(s)]
1034
1035Extra scons options:
1036%(options)s
1037
1038Global build variables:
1039%(global_vars)s
1040
1041%(local_vars)s
1042''' % help_texts)
1043