SConstruct revision 10319
1# -*- mode:python -*-
2
3# Copyright (c) 2013 ARM Limited
4# All rights reserved.
5#
6# The license below extends only to copyright in the software and shall
7# not be construed as granting a license to any other intellectual
8# property including but not limited to intellectual property relating
9# to a hardware implementation of the functionality of the software
10# licensed hereunder.  You may use the software subject to the license
11# terms below provided that you ensure that this notice is replicated
12# unmodified and in its entirety in all distributions of the software,
13# modified or unmodified, in source code or in binary form.
14#
15# Copyright (c) 2011 Advanced Micro Devices, Inc.
16# Copyright (c) 2009 The Hewlett-Packard Development Company
17# Copyright (c) 2004-2005 The Regents of The University of Michigan
18# All rights reserved.
19#
20# Redistribution and use in source and binary forms, with or without
21# modification, are permitted provided that the following conditions are
22# met: redistributions of source code must retain the above copyright
23# notice, this list of conditions and the following disclaimer;
24# redistributions in binary form must reproduce the above copyright
25# notice, this list of conditions and the following disclaimer in the
26# documentation and/or other materials provided with the distribution;
27# neither the name of the copyright holders nor the names of its
28# contributors may be used to endorse or promote products derived from
29# this software without specific prior written permission.
30#
31# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
34# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
36# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
37# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
38# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
39# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
41# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42#
43# Authors: Steve Reinhardt
44#          Nathan Binkert
45
46###################################################
47#
48# SCons top-level build description (SConstruct) file.
49#
50# While in this directory ('gem5'), just type 'scons' to build the default
51# configuration (see below), or type 'scons build/<CONFIG>/<binary>'
52# to build some other configuration (e.g., 'build/ALPHA/gem5.opt' for
53# the optimized full-system version).
54#
55# You can build gem5 in a different directory as long as there is a
56# 'build/<CONFIG>' somewhere along the target path.  The build system
57# expects that all configs under the same build directory are being
58# built for the same host system.
59#
60# Examples:
61#
62#   The following two commands are equivalent.  The '-u' option tells
63#   scons to search up the directory tree for this SConstruct file.
64#   % cd <path-to-src>/gem5 ; scons build/ALPHA/gem5.debug
65#   % cd <path-to-src>/gem5/build/ALPHA; scons -u gem5.debug
66#
67#   The following two commands are equivalent and demonstrate building
68#   in a directory outside of the source tree.  The '-C' option tells
69#   scons to chdir to the specified directory to find this SConstruct
70#   file.
71#   % cd <path-to-src>/gem5 ; scons /local/foo/build/ALPHA/gem5.debug
72#   % cd /local/foo/build/ALPHA; scons -C <path-to-src>/gem5 gem5.debug
73#
74# You can use 'scons -H' to print scons options.  If you're in this
75# 'gem5' directory (or use -u or -C to tell scons where to find this
76# file), you can use 'scons -h' to print all the gem5-specific build
77# options as well.
78#
79###################################################
80
81# Check for recent-enough Python and SCons versions.
82try:
83    # Really old versions of scons only take two options for the
84    # function, so check once without the revision and once with the
85    # revision, the first instance will fail for stuff other than
86    # 0.98, and the second will fail for 0.98.0
87    EnsureSConsVersion(0, 98)
88    EnsureSConsVersion(0, 98, 1)
89except SystemExit, e:
90    print """
91For more details, see:
92    http://gem5.org/Dependencies
93"""
94    raise
95
96# We ensure the python version early because because python-config
97# requires python 2.5
98try:
99    EnsurePythonVersion(2, 5)
100except SystemExit, e:
101    print """
102You can use a non-default installation of the Python interpreter by
103rearranging your PATH so that scons finds the non-default 'python' and
104'python-config' first.
105
106For more details, see:
107    http://gem5.org/wiki/index.php/Using_a_non-default_Python_installation
108"""
109    raise
110
111# Global Python includes
112import itertools
113import os
114import re
115import subprocess
116import sys
117
118from os import mkdir, environ
119from os.path import abspath, basename, dirname, expanduser, normpath
120from os.path import exists,  isdir, isfile
121from os.path import join as joinpath, split as splitpath
122
123# SCons includes
124import SCons
125import SCons.Node
126
127extra_python_paths = [
128    Dir('src/python').srcnode().abspath, # gem5 includes
129    Dir('ext/ply').srcnode().abspath, # ply is used by several files
130    ]
131
132sys.path[1:1] = extra_python_paths
133
134from m5.util import compareVersions, readCommand
135from m5.util.terminal import get_termcap
136
137help_texts = {
138    "options" : "",
139    "global_vars" : "",
140    "local_vars" : ""
141}
142
143Export("help_texts")
144
145
146# There's a bug in scons in that (1) by default, the help texts from
147# AddOption() are supposed to be displayed when you type 'scons -h'
148# and (2) you can override the help displayed by 'scons -h' using the
149# Help() function, but these two features are incompatible: once
150# you've overridden the help text using Help(), there's no way to get
151# at the help texts from AddOptions.  See:
152#     http://scons.tigris.org/issues/show_bug.cgi?id=2356
153#     http://scons.tigris.org/issues/show_bug.cgi?id=2611
154# This hack lets us extract the help text from AddOptions and
155# re-inject it via Help().  Ideally someday this bug will be fixed and
156# we can just use AddOption directly.
157def AddLocalOption(*args, **kwargs):
158    col_width = 30
159
160    help = "  " + ", ".join(args)
161    if "help" in kwargs:
162        length = len(help)
163        if length >= col_width:
164            help += "\n" + " " * col_width
165        else:
166            help += " " * (col_width - length)
167        help += kwargs["help"]
168    help_texts["options"] += help + "\n"
169
170    AddOption(*args, **kwargs)
171
172AddLocalOption('--colors', dest='use_colors', action='store_true',
173               help="Add color to abbreviated scons output")
174AddLocalOption('--no-colors', dest='use_colors', action='store_false',
175               help="Don't add color to abbreviated scons output")
176AddLocalOption('--default', dest='default', type='string', action='store',
177               help='Override which build_opts file to use for defaults')
178AddLocalOption('--ignore-style', dest='ignore_style', action='store_true',
179               help='Disable style checking hooks')
180AddLocalOption('--no-lto', dest='no_lto', action='store_true',
181               help='Disable Link-Time Optimization for fast')
182AddLocalOption('--update-ref', dest='update_ref', action='store_true',
183               help='Update test reference outputs')
184AddLocalOption('--verbose', dest='verbose', action='store_true',
185               help='Print full tool command lines')
186
187termcap = get_termcap(GetOption('use_colors'))
188
189########################################################################
190#
191# Set up the main build environment.
192#
193########################################################################
194
195# export TERM so that clang reports errors in color
196use_vars = set([ 'AS', 'AR', 'CC', 'CXX', 'HOME', 'LD_LIBRARY_PATH',
197                 'LIBRARY_PATH', 'PATH', 'PKG_CONFIG_PATH', 'PROTOC',
198                 'PYTHONPATH', 'RANLIB', 'SWIG', 'TERM' ])
199
200use_prefixes = [
201    "M5",           # M5 configuration (e.g., path to kernels)
202    "DISTCC_",      # distcc (distributed compiler wrapper) configuration
203    "CCACHE_",      # ccache (caching compiler wrapper) configuration
204    "CCC_",         # clang static analyzer configuration
205    ]
206
207use_env = {}
208for key,val in os.environ.iteritems():
209    if key in use_vars or \
210            any([key.startswith(prefix) for prefix in use_prefixes]):
211        use_env[key] = val
212
213main = Environment(ENV=use_env)
214main.Decider('MD5-timestamp')
215main.root = Dir(".")         # The current directory (where this file lives).
216main.srcdir = Dir("src")     # The source directory
217
218main_dict_keys = main.Dictionary().keys()
219
220# Check that we have a C/C++ compiler
221if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
222    print "No C++ compiler installed (package g++ on Ubuntu and RedHat)"
223    Exit(1)
224
225# Check that swig is present
226if not 'SWIG' in main_dict_keys:
227    print "swig is not installed (package swig on Ubuntu and RedHat)"
228    Exit(1)
229
230# add useful python code PYTHONPATH so it can be used by subprocesses
231# as well
232main.AppendENVPath('PYTHONPATH', extra_python_paths)
233
234########################################################################
235#
236# Mercurial Stuff.
237#
238# If the gem5 directory is a mercurial repository, we should do some
239# extra things.
240#
241########################################################################
242
243hgdir = main.root.Dir(".hg")
244
245mercurial_style_message = """
246You're missing the gem5 style hook, which automatically checks your code
247against the gem5 style rules on hg commit and qrefresh commands.  This
248script will now install the hook in your .hg/hgrc file.
249Press enter to continue, or ctrl-c to abort: """
250
251mercurial_style_hook = """
252# The following lines were automatically added by gem5/SConstruct
253# to provide the gem5 style-checking hooks
254[extensions]
255style = %s/util/style.py
256
257[hooks]
258pretxncommit.style = python:style.check_style
259pre-qrefresh.style = python:style.check_style
260# End of SConstruct additions
261
262""" % (main.root.abspath)
263
264mercurial_lib_not_found = """
265Mercurial libraries cannot be found, ignoring style hook.  If
266you are a gem5 developer, please fix this and run the style
267hook. It is important.
268"""
269
270# Check for style hook and prompt for installation if it's not there.
271# Skip this if --ignore-style was specified, there's no .hg dir to
272# install a hook in, or there's no interactive terminal to prompt.
273if not GetOption('ignore_style') and hgdir.exists() and sys.stdin.isatty():
274    style_hook = True
275    try:
276        from mercurial import ui
277        ui = ui.ui()
278        ui.readconfig(hgdir.File('hgrc').abspath)
279        style_hook = ui.config('hooks', 'pretxncommit.style', None) and \
280                     ui.config('hooks', 'pre-qrefresh.style', None)
281    except ImportError:
282        print mercurial_lib_not_found
283
284    if not style_hook:
285        print mercurial_style_message,
286        # continue unless user does ctrl-c/ctrl-d etc.
287        try:
288            raw_input()
289        except:
290            print "Input exception, exiting scons.\n"
291            sys.exit(1)
292        hgrc_path = '%s/.hg/hgrc' % main.root.abspath
293        print "Adding style hook to", hgrc_path, "\n"
294        try:
295            hgrc = open(hgrc_path, 'a')
296            hgrc.write(mercurial_style_hook)
297            hgrc.close()
298        except:
299            print "Error updating", hgrc_path
300            sys.exit(1)
301
302
303###################################################
304#
305# Figure out which configurations to set up based on the path(s) of
306# the target(s).
307#
308###################################################
309
310# Find default configuration & binary.
311Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))
312
313# helper function: find last occurrence of element in list
314def rfind(l, elt, offs = -1):
315    for i in range(len(l)+offs, 0, -1):
316        if l[i] == elt:
317            return i
318    raise ValueError, "element not found"
319
320# Take a list of paths (or SCons Nodes) and return a list with all
321# paths made absolute and ~-expanded.  Paths will be interpreted
322# relative to the launch directory unless a different root is provided
323def makePathListAbsolute(path_list, root=GetLaunchDir()):
324    return [abspath(joinpath(root, expanduser(str(p))))
325            for p in path_list]
326
327# Each target must have 'build' in the interior of the path; the
328# directory below this will determine the build parameters.  For
329# example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
330# recognize that ALPHA_SE specifies the configuration because it
331# follow 'build' in the build path.
332
333# The funky assignment to "[:]" is needed to replace the list contents
334# in place rather than reassign the symbol to a new list, which
335# doesn't work (obviously!).
336BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
337
338# Generate a list of the unique build roots and configs that the
339# collected targets reference.
340variant_paths = []
341build_root = None
342for t in BUILD_TARGETS:
343    path_dirs = t.split('/')
344    try:
345        build_top = rfind(path_dirs, 'build', -2)
346    except:
347        print "Error: no non-leaf 'build' dir found on target path", t
348        Exit(1)
349    this_build_root = joinpath('/',*path_dirs[:build_top+1])
350    if not build_root:
351        build_root = this_build_root
352    else:
353        if this_build_root != build_root:
354            print "Error: build targets not under same build root\n"\
355                  "  %s\n  %s" % (build_root, this_build_root)
356            Exit(1)
357    variant_path = joinpath('/',*path_dirs[:build_top+2])
358    if variant_path not in variant_paths:
359        variant_paths.append(variant_path)
360
361# Make sure build_root exists (might not if this is the first build there)
362if not isdir(build_root):
363    mkdir(build_root)
364main['BUILDROOT'] = build_root
365
366Export('main')
367
368main.SConsignFile(joinpath(build_root, "sconsign"))
369
370# Default duplicate option is to use hard links, but this messes up
371# when you use emacs to edit a file in the target dir, as emacs moves
372# file to file~ then copies to file, breaking the link.  Symbolic
373# (soft) links work better.
374main.SetOption('duplicate', 'soft-copy')
375
376#
377# Set up global sticky variables... these are common to an entire build
378# tree (not specific to a particular build like ALPHA_SE)
379#
380
381global_vars_file = joinpath(build_root, 'variables.global')
382
383global_vars = Variables(global_vars_file, args=ARGUMENTS)
384
385global_vars.AddVariables(
386    ('CC', 'C compiler', environ.get('CC', main['CC'])),
387    ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
388    ('SWIG', 'SWIG tool', environ.get('SWIG', main['SWIG'])),
389    ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
390    ('BATCH', 'Use batch pool for build and tests', False),
391    ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
392    ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
393    ('EXTRAS', 'Add extra directories to the compilation', '')
394    )
395
396# Update main environment with values from ARGUMENTS & global_vars_file
397global_vars.Update(main)
398help_texts["global_vars"] += global_vars.GenerateHelpText(main)
399
400# Save sticky variable settings back to current variables file
401global_vars.Save(global_vars_file, main)
402
403# Parse EXTRAS variable to build list of all directories where we're
404# look for sources etc.  This list is exported as extras_dir_list.
405base_dir = main.srcdir.abspath
406if main['EXTRAS']:
407    extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
408else:
409    extras_dir_list = []
410
411Export('base_dir')
412Export('extras_dir_list')
413
414# the ext directory should be on the #includes path
415main.Append(CPPPATH=[Dir('ext')])
416
417def strip_build_path(path, env):
418    path = str(path)
419    variant_base = env['BUILDROOT'] + os.path.sep
420    if path.startswith(variant_base):
421        path = path[len(variant_base):]
422    elif path.startswith('build/'):
423        path = path[6:]
424    return path
425
426# Generate a string of the form:
427#   common/path/prefix/src1, src2 -> tgt1, tgt2
428# to print while building.
429class Transform(object):
430    # all specific color settings should be here and nowhere else
431    tool_color = termcap.Normal
432    pfx_color = termcap.Yellow
433    srcs_color = termcap.Yellow + termcap.Bold
434    arrow_color = termcap.Blue + termcap.Bold
435    tgts_color = termcap.Yellow + termcap.Bold
436
437    def __init__(self, tool, max_sources=99):
438        self.format = self.tool_color + (" [%8s] " % tool) \
439                      + self.pfx_color + "%s" \
440                      + self.srcs_color + "%s" \
441                      + self.arrow_color + " -> " \
442                      + self.tgts_color + "%s" \
443                      + termcap.Normal
444        self.max_sources = max_sources
445
446    def __call__(self, target, source, env, for_signature=None):
447        # truncate source list according to max_sources param
448        source = source[0:self.max_sources]
449        def strip(f):
450            return strip_build_path(str(f), env)
451        if len(source) > 0:
452            srcs = map(strip, source)
453        else:
454            srcs = ['']
455        tgts = map(strip, target)
456        # surprisingly, os.path.commonprefix is a dumb char-by-char string
457        # operation that has nothing to do with paths.
458        com_pfx = os.path.commonprefix(srcs + tgts)
459        com_pfx_len = len(com_pfx)
460        if com_pfx:
461            # do some cleanup and sanity checking on common prefix
462            if com_pfx[-1] == ".":
463                # prefix matches all but file extension: ok
464                # back up one to change 'foo.cc -> o' to 'foo.cc -> .o'
465                com_pfx = com_pfx[0:-1]
466            elif com_pfx[-1] == "/":
467                # common prefix is directory path: OK
468                pass
469            else:
470                src0_len = len(srcs[0])
471                tgt0_len = len(tgts[0])
472                if src0_len == com_pfx_len:
473                    # source is a substring of target, OK
474                    pass
475                elif tgt0_len == com_pfx_len:
476                    # target is a substring of source, need to back up to
477                    # avoid empty string on RHS of arrow
478                    sep_idx = com_pfx.rfind(".")
479                    if sep_idx != -1:
480                        com_pfx = com_pfx[0:sep_idx]
481                    else:
482                        com_pfx = ''
483                elif src0_len > com_pfx_len and srcs[0][com_pfx_len] == ".":
484                    # still splitting at file extension: ok
485                    pass
486                else:
487                    # probably a fluke; ignore it
488                    com_pfx = ''
489        # recalculate length in case com_pfx was modified
490        com_pfx_len = len(com_pfx)
491        def fmt(files):
492            f = map(lambda s: s[com_pfx_len:], files)
493            return ', '.join(f)
494        return self.format % (com_pfx, fmt(srcs), fmt(tgts))
495
496Export('Transform')
497
498# enable the regression script to use the termcap
499main['TERMCAP'] = termcap
500
501if GetOption('verbose'):
502    def MakeAction(action, string, *args, **kwargs):
503        return Action(action, *args, **kwargs)
504else:
505    MakeAction = Action
506    main['CCCOMSTR']        = Transform("CC")
507    main['CXXCOMSTR']       = Transform("CXX")
508    main['ASCOMSTR']        = Transform("AS")
509    main['SWIGCOMSTR']      = Transform("SWIG")
510    main['ARCOMSTR']        = Transform("AR", 0)
511    main['LINKCOMSTR']      = Transform("LINK", 0)
512    main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
513    main['M4COMSTR']        = Transform("M4")
514    main['SHCCCOMSTR']      = Transform("SHCC")
515    main['SHCXXCOMSTR']     = Transform("SHCXX")
516Export('MakeAction')
517
518# Initialize the Link-Time Optimization (LTO) flags
519main['LTO_CCFLAGS'] = []
520main['LTO_LDFLAGS'] = []
521
522# According to the readme, tcmalloc works best if the compiler doesn't
523# assume that we're using the builtin malloc and friends. These flags
524# are compiler-specific, so we need to set them after we detect which
525# compiler we're using.
526main['TCMALLOC_CCFLAGS'] = []
527
528CXX_version = readCommand([main['CXX'],'--version'], exception=False)
529CXX_V = readCommand([main['CXX'],'-V'], exception=False)
530
531main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
532main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
533if main['GCC'] + main['CLANG'] > 1:
534    print 'Error: How can we have two at the same time?'
535    Exit(1)
536
537# Set up default C++ compiler flags
538if main['GCC'] or main['CLANG']:
539    # As gcc and clang share many flags, do the common parts here
540    main.Append(CCFLAGS=['-pipe'])
541    main.Append(CCFLAGS=['-fno-strict-aliasing'])
542    # Enable -Wall and then disable the few warnings that we
543    # consistently violate
544    main.Append(CCFLAGS=['-Wall', '-Wno-sign-compare', '-Wundef'])
545    # We always compile using C++11, but only gcc >= 4.7 and clang 3.1
546    # actually use that name, so we stick with c++0x
547    main.Append(CXXFLAGS=['-std=c++0x'])
548    # Add selected sanity checks from -Wextra
549    main.Append(CXXFLAGS=['-Wmissing-field-initializers',
550                          '-Woverloaded-virtual'])
551else:
552    print termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal,
553    print "Don't know what compiler options to use for your compiler."
554    print termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX']
555    print termcap.Yellow + '       version:' + termcap.Normal,
556    if not CXX_version:
557        print termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +\
558               termcap.Normal
559    else:
560        print CXX_version.replace('\n', '<nl>')
561    print "       If you're trying to use a compiler other than GCC"
562    print "       or clang, there appears to be something wrong with your"
563    print "       environment."
564    print "       "
565    print "       If you are trying to use a compiler other than those listed"
566    print "       above you will need to ease fix SConstruct and "
567    print "       src/SConscript to support that compiler."
568    Exit(1)
569
570if main['GCC']:
571    # Check for a supported version of gcc. >= 4.6 is chosen for its
572    # level of c++11 support. See
573    # http://gcc.gnu.org/projects/cxx0x.html for details. 4.6 is also
574    # the first version with proper LTO support.
575    gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
576    if compareVersions(gcc_version, "4.6") < 0:
577        print 'Error: gcc version 4.6 or newer required.'
578        print '       Installed version:', gcc_version
579        Exit(1)
580
581    main['GCC_VERSION'] = gcc_version
582
583    # gcc from version 4.8 and above generates "rep; ret" instructions
584    # to avoid performance penalties on certain AMD chips. Older
585    # assemblers detect this as an error, "Error: expecting string
586    # instruction after `rep'"
587    if compareVersions(gcc_version, "4.8") > 0:
588        as_version = readCommand([main['AS'], '-v', '/dev/null'],
589                                 exception=False).split()
590
591        if not as_version or compareVersions(as_version[-1], "2.23") < 0:
592            print termcap.Yellow + termcap.Bold + \
593                'Warning: This combination of gcc and binutils have' + \
594                ' known incompatibilities.\n' + \
595                '         If you encounter build problems, please update ' + \
596                'binutils to 2.23.' + \
597                termcap.Normal
598
599    # Add the appropriate Link-Time Optimization (LTO) flags
600    # unless LTO is explicitly turned off. Note that these flags
601    # are only used by the fast target.
602    if not GetOption('no_lto'):
603        # Pass the LTO flag when compiling to produce GIMPLE
604        # output, we merely create the flags here and only append
605        # them later/
606        main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
607
608        # Use the same amount of jobs for LTO as we are running
609        # scons with, we hardcode the use of the linker plugin
610        # which requires either gold or GNU ld >= 2.21
611        main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs'),
612                               '-fuse-linker-plugin']
613
614    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
615                                  '-fno-builtin-realloc', '-fno-builtin-free'])
616
617elif main['CLANG']:
618    # Check for a supported version of clang, >= 3.0 is needed to
619    # support similar features as gcc 4.6. See
620    # http://clang.llvm.org/cxx_status.html for details
621    clang_version_re = re.compile(".* version (\d+\.\d+)")
622    clang_version_match = clang_version_re.search(CXX_version)
623    if (clang_version_match):
624        clang_version = clang_version_match.groups()[0]
625        if compareVersions(clang_version, "3.0") < 0:
626            print 'Error: clang version 3.0 or newer required.'
627            print '       Installed version:', clang_version
628            Exit(1)
629    else:
630        print 'Error: Unable to determine clang version.'
631        Exit(1)
632
633    # clang has a few additional warnings that we disable,
634    # tautological comparisons are allowed due to unsigned integers
635    # being compared to constants that happen to be 0, and extraneous
636    # parantheses are allowed due to Ruby's printing of the AST,
637    # finally self assignments are allowed as the generated CPU code
638    # is relying on this
639    main.Append(CCFLAGS=['-Wno-tautological-compare',
640                         '-Wno-parentheses',
641                         '-Wno-self-assign',
642                         # Some versions of libstdc++ (4.8?) seem to
643                         # use struct hash and class hash
644                         # interchangeably.
645                         '-Wno-mismatched-tags',
646                         ])
647
648    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
649
650    # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
651    # opposed to libstdc++, as the later is dated.
652    if sys.platform == "darwin":
653        main.Append(CXXFLAGS=['-stdlib=libc++'])
654        main.Append(LIBS=['c++'])
655
656else:
657    print termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal,
658    print "Don't know what compiler options to use for your compiler."
659    print termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX']
660    print termcap.Yellow + '       version:' + termcap.Normal,
661    if not CXX_version:
662        print termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +\
663               termcap.Normal
664    else:
665        print CXX_version.replace('\n', '<nl>')
666    print "       If you're trying to use a compiler other than GCC"
667    print "       or clang, there appears to be something wrong with your"
668    print "       environment."
669    print "       "
670    print "       If you are trying to use a compiler other than those listed"
671    print "       above you will need to ease fix SConstruct and "
672    print "       src/SConscript to support that compiler."
673    Exit(1)
674
675# Set up common yacc/bison flags (needed for Ruby)
676main['YACCFLAGS'] = '-d'
677main['YACCHXXFILESUFFIX'] = '.hh'
678
679# Do this after we save setting back, or else we'll tack on an
680# extra 'qdo' every time we run scons.
681if main['BATCH']:
682    main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
683    main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
684    main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
685    main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
686    main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
687
688if sys.platform == 'cygwin':
689    # cygwin has some header file issues...
690    main.Append(CCFLAGS=["-Wno-uninitialized"])
691
692# Check for the protobuf compiler
693protoc_version = readCommand([main['PROTOC'], '--version'],
694                             exception='').split()
695
696# First two words should be "libprotoc x.y.z"
697if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
698    print termcap.Yellow + termcap.Bold + \
699        'Warning: Protocol buffer compiler (protoc) not found.\n' + \
700        '         Please install protobuf-compiler for tracing support.' + \
701        termcap.Normal
702    main['PROTOC'] = False
703else:
704    # Based on the availability of the compress stream wrappers,
705    # require 2.1.0
706    min_protoc_version = '2.1.0'
707    if compareVersions(protoc_version[1], min_protoc_version) < 0:
708        print termcap.Yellow + termcap.Bold + \
709            'Warning: protoc version', min_protoc_version, \
710            'or newer required.\n' + \
711            '         Installed version:', protoc_version[1], \
712            termcap.Normal
713        main['PROTOC'] = False
714    else:
715        # Attempt to determine the appropriate include path and
716        # library path using pkg-config, that means we also need to
717        # check for pkg-config. Note that it is possible to use
718        # protobuf without the involvement of pkg-config. Later on we
719        # check go a library config check and at that point the test
720        # will fail if libprotobuf cannot be found.
721        if readCommand(['pkg-config', '--version'], exception=''):
722            try:
723                # Attempt to establish what linking flags to add for protobuf
724                # using pkg-config
725                main.ParseConfig('pkg-config --cflags --libs-only-L protobuf')
726            except:
727                print termcap.Yellow + termcap.Bold + \
728                    'Warning: pkg-config could not get protobuf flags.' + \
729                    termcap.Normal
730
731# Check for SWIG
732if not main.has_key('SWIG'):
733    print 'Error: SWIG utility not found.'
734    print '       Please install (see http://www.swig.org) and retry.'
735    Exit(1)
736
737# Check for appropriate SWIG version
738swig_version = readCommand([main['SWIG'], '-version'], exception='').split()
739# First 3 words should be "SWIG Version x.y.z"
740if len(swig_version) < 3 or \
741        swig_version[0] != 'SWIG' or swig_version[1] != 'Version':
742    print 'Error determining SWIG version.'
743    Exit(1)
744
745min_swig_version = '2.0.4'
746if compareVersions(swig_version[2], min_swig_version) < 0:
747    print 'Error: SWIG version', min_swig_version, 'or newer required.'
748    print '       Installed version:', swig_version[2]
749    Exit(1)
750
751# Set up SWIG flags & scanner
752swig_flags=Split('-c++ -python -modern -templatereduce $_CPPINCFLAGS')
753main.Append(SWIGFLAGS=swig_flags)
754
755# filter out all existing swig scanners, they mess up the dependency
756# stuff for some reason
757scanners = []
758for scanner in main['SCANNERS']:
759    skeys = scanner.skeys
760    if skeys == '.i':
761        continue
762
763    if isinstance(skeys, (list, tuple)) and '.i' in skeys:
764        continue
765
766    scanners.append(scanner)
767
768# add the new swig scanner that we like better
769from SCons.Scanner import ClassicCPP as CPPScanner
770swig_inc_re = '^[ \t]*[%,#][ \t]*(?:include|import)[ \t]*(<|")([^>"]+)(>|")'
771scanners.append(CPPScanner("SwigScan", [ ".i" ], "CPPPATH", swig_inc_re))
772
773# replace the scanners list that has what we want
774main['SCANNERS'] = scanners
775
776# Add a custom Check function to the Configure context so that we can
777# figure out if the compiler adds leading underscores to global
778# variables.  This is needed for the autogenerated asm files that we
779# use for embedding the python code.
780def CheckLeading(context):
781    context.Message("Checking for leading underscore in global variables...")
782    # 1) Define a global variable called x from asm so the C compiler
783    #    won't change the symbol at all.
784    # 2) Declare that variable.
785    # 3) Use the variable
786    #
787    # If the compiler prepends an underscore, this will successfully
788    # link because the external symbol 'x' will be called '_x' which
789    # was defined by the asm statement.  If the compiler does not
790    # prepend an underscore, this will not successfully link because
791    # '_x' will have been defined by assembly, while the C portion of
792    # the code will be trying to use 'x'
793    ret = context.TryLink('''
794        asm(".globl _x; _x: .byte 0");
795        extern int x;
796        int main() { return x; }
797        ''', extension=".c")
798    context.env.Append(LEADING_UNDERSCORE=ret)
799    context.Result(ret)
800    return ret
801
802# Add a custom Check function to test for structure members.
803def CheckMember(context, include, decl, member, include_quotes="<>"):
804    context.Message("Checking for member %s in %s..." %
805                    (member, decl))
806    text = """
807#include %(header)s
808int main(){
809  %(decl)s test;
810  (void)test.%(member)s;
811  return 0;
812};
813""" % { "header" : include_quotes[0] + include + include_quotes[1],
814        "decl" : decl,
815        "member" : member,
816        }
817
818    ret = context.TryCompile(text, extension=".cc")
819    context.Result(ret)
820    return ret
821
822# Platform-specific configuration.  Note again that we assume that all
823# builds under a given build root run on the same host platform.
824conf = Configure(main,
825                 conf_dir = joinpath(build_root, '.scons_config'),
826                 log_file = joinpath(build_root, 'scons_config.log'),
827                 custom_tests = {
828        'CheckLeading' : CheckLeading,
829        'CheckMember' : CheckMember,
830        })
831
832# Check for leading underscores.  Don't really need to worry either
833# way so don't need to check the return code.
834conf.CheckLeading()
835
836# Check if we should compile a 64 bit binary on Mac OS X/Darwin
837try:
838    import platform
839    uname = platform.uname()
840    if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
841        if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
842            main.Append(CCFLAGS=['-arch', 'x86_64'])
843            main.Append(CFLAGS=['-arch', 'x86_64'])
844            main.Append(LINKFLAGS=['-arch', 'x86_64'])
845            main.Append(ASFLAGS=['-arch', 'x86_64'])
846except:
847    pass
848
849# Recent versions of scons substitute a "Null" object for Configure()
850# when configuration isn't necessary, e.g., if the "--help" option is
851# present.  Unfortuantely this Null object always returns false,
852# breaking all our configuration checks.  We replace it with our own
853# more optimistic null object that returns True instead.
854if not conf:
855    def NullCheck(*args, **kwargs):
856        return True
857
858    class NullConf:
859        def __init__(self, env):
860            self.env = env
861        def Finish(self):
862            return self.env
863        def __getattr__(self, mname):
864            return NullCheck
865
866    conf = NullConf(main)
867
868# Cache build files in the supplied directory.
869if main['M5_BUILD_CACHE']:
870    print 'Using build cache located at', main['M5_BUILD_CACHE']
871    CacheDir(main['M5_BUILD_CACHE'])
872
873# Find Python include and library directories for embedding the
874# interpreter. We rely on python-config to resolve the appropriate
875# includes and linker flags. ParseConfig does not seem to understand
876# the more exotic linker flags such as -Xlinker and -export-dynamic so
877# we add them explicitly below. If you want to link in an alternate
878# version of python, see above for instructions on how to invoke
879# scons with the appropriate PATH set.
880#
881# First we check if python2-config exists, else we use python-config
882python_config = readCommand(['which', 'python2-config'], exception='').strip()
883if not os.path.exists(python_config):
884    python_config = readCommand(['which', 'python-config'],
885                                exception='').strip()
886py_includes = readCommand([python_config, '--includes'],
887                          exception='').split()
888# Strip the -I from the include folders before adding them to the
889# CPPPATH
890main.Append(CPPPATH=map(lambda inc: inc[2:], py_includes))
891
892# Read the linker flags and split them into libraries and other link
893# flags. The libraries are added later through the call the CheckLib.
894py_ld_flags = readCommand([python_config, '--ldflags'], exception='').split()
895py_libs = []
896for lib in py_ld_flags:
897     if not lib.startswith('-l'):
898         main.Append(LINKFLAGS=[lib])
899     else:
900         lib = lib[2:]
901         if lib not in py_libs:
902             py_libs.append(lib)
903
904# verify that this stuff works
905if not conf.CheckHeader('Python.h', '<>'):
906    print "Error: can't find Python.h header in", py_includes
907    print "Install Python headers (package python-dev on Ubuntu and RedHat)"
908    Exit(1)
909
910for lib in py_libs:
911    if not conf.CheckLib(lib):
912        print "Error: can't find library %s required by python" % lib
913        Exit(1)
914
915# On Solaris you need to use libsocket for socket ops
916if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
917   if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
918       print "Can't find library with socket calls (e.g. accept())"
919       Exit(1)
920
921# Check for zlib.  If the check passes, libz will be automatically
922# added to the LIBS environment variable.
923if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
924    print 'Error: did not find needed zlib compression library '\
925          'and/or zlib.h header file.'
926    print '       Please install zlib and try again.'
927    Exit(1)
928
929# If we have the protobuf compiler, also make sure we have the
930# development libraries. If the check passes, libprotobuf will be
931# automatically added to the LIBS environment variable. After
932# this, we can use the HAVE_PROTOBUF flag to determine if we have
933# got both protoc and libprotobuf available.
934main['HAVE_PROTOBUF'] = main['PROTOC'] and \
935    conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
936                            'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
937
938# If we have the compiler but not the library, print another warning.
939if main['PROTOC'] and not main['HAVE_PROTOBUF']:
940    print termcap.Yellow + termcap.Bold + \
941        'Warning: did not find protocol buffer library and/or headers.\n' + \
942    '       Please install libprotobuf-dev for tracing support.' + \
943    termcap.Normal
944
945# Check for librt.
946have_posix_clock = \
947    conf.CheckLibWithHeader(None, 'time.h', 'C',
948                            'clock_nanosleep(0,0,NULL,NULL);') or \
949    conf.CheckLibWithHeader('rt', 'time.h', 'C',
950                            'clock_nanosleep(0,0,NULL,NULL);')
951
952have_posix_timers = \
953    conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
954                            'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
955
956if conf.CheckLib('tcmalloc'):
957    main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
958elif conf.CheckLib('tcmalloc_minimal'):
959    main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
960else:
961    print termcap.Yellow + termcap.Bold + \
962          "You can get a 12% performance improvement by installing tcmalloc "\
963          "(libgoogle-perftools-dev package on Ubuntu or RedHat)." + \
964          termcap.Normal
965
966if not have_posix_clock:
967    print "Can't find library for POSIX clocks."
968
969# Check for <fenv.h> (C99 FP environment control)
970have_fenv = conf.CheckHeader('fenv.h', '<>')
971if not have_fenv:
972    print "Warning: Header file <fenv.h> not found."
973    print "         This host has no IEEE FP rounding mode control."
974
975# Check if we should enable KVM-based hardware virtualization. The API
976# we rely on exists since version 2.6.36 of the kernel, but somehow
977# the KVM_API_VERSION does not reflect the change. We test for one of
978# the types as a fall back.
979have_kvm = conf.CheckHeader('linux/kvm.h', '<>') and \
980    conf.CheckTypeSize('struct kvm_xsave', '#include <linux/kvm.h>') != 0
981if not have_kvm:
982    print "Info: Compatible header file <linux/kvm.h> not found, " \
983        "disabling KVM support."
984
985# Check if the requested target ISA is compatible with the host
986def is_isa_kvm_compatible(isa):
987    isa_comp_table = {
988        "arm" : ( "armv7l" ),
989        "x86" : ( "x86_64" ),
990        }
991    try:
992        import platform
993        host_isa = platform.machine()
994    except:
995        print "Warning: Failed to determine host ISA."
996        return False
997
998    return host_isa in isa_comp_table.get(isa, [])
999
1000
1001# Check if the exclude_host attribute is available. We want this to
1002# get accurate instruction counts in KVM.
1003main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
1004    'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
1005
1006
1007######################################################################
1008#
1009# Finish the configuration
1010#
1011main = conf.Finish()
1012
1013######################################################################
1014#
1015# Collect all non-global variables
1016#
1017
1018# Define the universe of supported ISAs
1019all_isa_list = [ ]
1020Export('all_isa_list')
1021
1022class CpuModel(object):
1023    '''The CpuModel class encapsulates everything the ISA parser needs to
1024    know about a particular CPU model.'''
1025
1026    # Dict of available CPU model objects.  Accessible as CpuModel.dict.
1027    dict = {}
1028
1029    # Constructor.  Automatically adds models to CpuModel.dict.
1030    def __init__(self, name, default=False):
1031        self.name = name           # name of model
1032
1033        # This cpu is enabled by default
1034        self.default = default
1035
1036        # Add self to dict
1037        if name in CpuModel.dict:
1038            raise AttributeError, "CpuModel '%s' already registered" % name
1039        CpuModel.dict[name] = self
1040
1041Export('CpuModel')
1042
1043# Sticky variables get saved in the variables file so they persist from
1044# one invocation to the next (unless overridden, in which case the new
1045# value becomes sticky).
1046sticky_vars = Variables(args=ARGUMENTS)
1047Export('sticky_vars')
1048
1049# Sticky variables that should be exported
1050export_vars = []
1051Export('export_vars')
1052
1053# For Ruby
1054all_protocols = []
1055Export('all_protocols')
1056protocol_dirs = []
1057Export('protocol_dirs')
1058slicc_includes = []
1059Export('slicc_includes')
1060
1061# Walk the tree and execute all SConsopts scripts that wil add to the
1062# above variables
1063if GetOption('verbose'):
1064    print "Reading SConsopts"
1065for bdir in [ base_dir ] + extras_dir_list:
1066    if not isdir(bdir):
1067        print "Error: directory '%s' does not exist" % bdir
1068        Exit(1)
1069    for root, dirs, files in os.walk(bdir):
1070        if 'SConsopts' in files:
1071            if GetOption('verbose'):
1072                print "Reading", joinpath(root, 'SConsopts')
1073            SConscript(joinpath(root, 'SConsopts'))
1074
1075all_isa_list.sort()
1076
1077sticky_vars.AddVariables(
1078    EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
1079    ListVariable('CPU_MODELS', 'CPU models',
1080                 sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
1081                 sorted(CpuModel.dict.keys())),
1082    BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
1083                 False),
1084    BoolVariable('SS_COMPATIBLE_FP',
1085                 'Make floating-point results compatible with SimpleScalar',
1086                 False),
1087    BoolVariable('USE_SSE2',
1088                 'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
1089                 False),
1090    BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
1091    BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
1092    BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability', False),
1093    BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models', have_kvm),
1094    EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1095                  all_protocols),
1096    )
1097
1098# These variables get exported to #defines in config/*.hh (see src/SConscript).
1099export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'CP_ANNOTATE',
1100                'USE_POSIX_CLOCK', 'PROTOCOL', 'HAVE_PROTOBUF',
1101                'HAVE_PERF_ATTR_EXCLUDE_HOST']
1102
1103###################################################
1104#
1105# Define a SCons builder for configuration flag headers.
1106#
1107###################################################
1108
1109# This function generates a config header file that #defines the
1110# variable symbol to the current variable setting (0 or 1).  The source
1111# operands are the name of the variable and a Value node containing the
1112# value of the variable.
1113def build_config_file(target, source, env):
1114    (variable, value) = [s.get_contents() for s in source]
1115    f = file(str(target[0]), 'w')
1116    print >> f, '#define', variable, value
1117    f.close()
1118    return None
1119
1120# Combine the two functions into a scons Action object.
1121config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1122
1123# The emitter munges the source & target node lists to reflect what
1124# we're really doing.
1125def config_emitter(target, source, env):
1126    # extract variable name from Builder arg
1127    variable = str(target[0])
1128    # True target is config header file
1129    target = joinpath('config', variable.lower() + '.hh')
1130    val = env[variable]
1131    if isinstance(val, bool):
1132        # Force value to 0/1
1133        val = int(val)
1134    elif isinstance(val, str):
1135        val = '"' + val + '"'
1136
1137    # Sources are variable name & value (packaged in SCons Value nodes)
1138    return ([target], [Value(variable), Value(val)])
1139
1140config_builder = Builder(emitter = config_emitter, action = config_action)
1141
1142main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1143
1144# libelf build is shared across all configs in the build root.
1145main.SConscript('ext/libelf/SConscript',
1146                variant_dir = joinpath(build_root, 'libelf'))
1147
1148# gzstream build is shared across all configs in the build root.
1149main.SConscript('ext/gzstream/SConscript',
1150                variant_dir = joinpath(build_root, 'gzstream'))
1151
1152# libfdt build is shared across all configs in the build root.
1153main.SConscript('ext/libfdt/SConscript',
1154                variant_dir = joinpath(build_root, 'libfdt'))
1155
1156# fputils build is shared across all configs in the build root.
1157main.SConscript('ext/fputils/SConscript',
1158                variant_dir = joinpath(build_root, 'fputils'))
1159
1160# DRAMSim2 build is shared across all configs in the build root.
1161main.SConscript('ext/dramsim2/SConscript',
1162                variant_dir = joinpath(build_root, 'dramsim2'))
1163
1164###################################################
1165#
1166# This function is used to set up a directory with switching headers
1167#
1168###################################################
1169
1170main['ALL_ISA_LIST'] = all_isa_list
1171all_isa_deps = {}
1172def make_switching_dir(dname, switch_headers, env):
1173    # Generate the header.  target[0] is the full path of the output
1174    # header to generate.  'source' is a dummy variable, since we get the
1175    # list of ISAs from env['ALL_ISA_LIST'].
1176    def gen_switch_hdr(target, source, env):
1177        fname = str(target[0])
1178        isa = env['TARGET_ISA'].lower()
1179        try:
1180            f = open(fname, 'w')
1181            print >>f, '#include "%s/%s/%s"' % (dname, isa, basename(fname))
1182            f.close()
1183        except IOError:
1184            print "Failed to create %s" % fname
1185            raise
1186
1187    # Build SCons Action object. 'varlist' specifies env vars that this
1188    # action depends on; when env['ALL_ISA_LIST'] changes these actions
1189    # should get re-executed.
1190    switch_hdr_action = MakeAction(gen_switch_hdr,
1191                          Transform("GENERATE"), varlist=['ALL_ISA_LIST'])
1192
1193    # Instantiate actions for each header
1194    for hdr in switch_headers:
1195        env.Command(hdr, [], switch_hdr_action)
1196
1197    isa_target = Dir('.').up().name.lower().replace('_', '-')
1198    env['PHONY_BASE'] = '#'+isa_target
1199    all_isa_deps[isa_target] = None
1200
1201Export('make_switching_dir')
1202
1203# all-isas -> all-deps -> all-environs -> all_targets
1204main.Alias('#all-isas', [])
1205main.Alias('#all-deps', '#all-isas')
1206
1207# Dummy target to ensure all environments are created before telling
1208# SCons what to actually make (the command line arguments).  We attach
1209# them to the dependence graph after the environments are complete.
1210ORIG_BUILD_TARGETS = list(BUILD_TARGETS) # force a copy; gets closure to work.
1211def environsComplete(target, source, env):
1212    for t in ORIG_BUILD_TARGETS:
1213        main.Depends('#all-targets', t)
1214
1215# Each build/* switching_dir attaches its *-environs target to #all-environs.
1216main.Append(BUILDERS = {'CompleteEnvirons' :
1217                        Builder(action=MakeAction(environsComplete, None))})
1218main.CompleteEnvirons('#all-environs', [])
1219
1220def doNothing(**ignored): pass
1221main.Append(BUILDERS = {'Dummy': Builder(action=MakeAction(doNothing, None))})
1222
1223# The final target to which all the original targets ultimately get attached.
1224main.Dummy('#all-targets', '#all-environs')
1225BUILD_TARGETS[:] = ['#all-targets']
1226
1227###################################################
1228#
1229# Define build environments for selected configurations.
1230#
1231###################################################
1232
1233for variant_path in variant_paths:
1234    if not GetOption('silent'):
1235        print "Building in", variant_path
1236
1237    # Make a copy of the build-root environment to use for this config.
1238    env = main.Clone()
1239    env['BUILDDIR'] = variant_path
1240
1241    # variant_dir is the tail component of build path, and is used to
1242    # determine the build parameters (e.g., 'ALPHA_SE')
1243    (build_root, variant_dir) = splitpath(variant_path)
1244
1245    # Set env variables according to the build directory config.
1246    sticky_vars.files = []
1247    # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1248    # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1249    # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1250    current_vars_file = joinpath(build_root, 'variables', variant_dir)
1251    if isfile(current_vars_file):
1252        sticky_vars.files.append(current_vars_file)
1253        if not GetOption('silent'):
1254            print "Using saved variables file %s" % current_vars_file
1255    else:
1256        # Build dir-specific variables file doesn't exist.
1257
1258        # Make sure the directory is there so we can create it later
1259        opt_dir = dirname(current_vars_file)
1260        if not isdir(opt_dir):
1261            mkdir(opt_dir)
1262
1263        # Get default build variables from source tree.  Variables are
1264        # normally determined by name of $VARIANT_DIR, but can be
1265        # overridden by '--default=' arg on command line.
1266        default = GetOption('default')
1267        opts_dir = joinpath(main.root.abspath, 'build_opts')
1268        if default:
1269            default_vars_files = [joinpath(build_root, 'variables', default),
1270                                  joinpath(opts_dir, default)]
1271        else:
1272            default_vars_files = [joinpath(opts_dir, variant_dir)]
1273        existing_files = filter(isfile, default_vars_files)
1274        if existing_files:
1275            default_vars_file = existing_files[0]
1276            sticky_vars.files.append(default_vars_file)
1277            print "Variables file %s not found,\n  using defaults in %s" \
1278                  % (current_vars_file, default_vars_file)
1279        else:
1280            print "Error: cannot find variables file %s or " \
1281                  "default file(s) %s" \
1282                  % (current_vars_file, ' or '.join(default_vars_files))
1283            Exit(1)
1284
1285    # Apply current variable settings to env
1286    sticky_vars.Update(env)
1287
1288    help_texts["local_vars"] += \
1289        "Build variables for %s:\n" % variant_dir \
1290                 + sticky_vars.GenerateHelpText(env)
1291
1292    # Process variable settings.
1293
1294    if not have_fenv and env['USE_FENV']:
1295        print "Warning: <fenv.h> not available; " \
1296              "forcing USE_FENV to False in", variant_dir + "."
1297        env['USE_FENV'] = False
1298
1299    if not env['USE_FENV']:
1300        print "Warning: No IEEE FP rounding mode control in", variant_dir + "."
1301        print "         FP results may deviate slightly from other platforms."
1302
1303    if env['EFENCE']:
1304        env.Append(LIBS=['efence'])
1305
1306    if env['USE_KVM']:
1307        if not have_kvm:
1308            print "Warning: Can not enable KVM, host seems to lack KVM support"
1309            env['USE_KVM'] = False
1310        elif not have_posix_timers:
1311            print "Warning: Can not enable KVM, host seems to lack support " \
1312                "for POSIX timers"
1313            env['USE_KVM'] = False
1314        elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1315            print "Info: KVM support disabled due to unsupported host and " \
1316                "target ISA combination"
1317            env['USE_KVM'] = False
1318
1319    # Warn about missing optional functionality
1320    if env['USE_KVM']:
1321        if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1322            print "Warning: perf_event headers lack support for the " \
1323                "exclude_host attribute. KVM instruction counts will " \
1324                "be inaccurate."
1325
1326    # Save sticky variable settings back to current variables file
1327    sticky_vars.Save(current_vars_file, env)
1328
1329    if env['USE_SSE2']:
1330        env.Append(CCFLAGS=['-msse2'])
1331
1332    # The src/SConscript file sets up the build rules in 'env' according
1333    # to the configured variables.  It returns a list of environments,
1334    # one for each variant build (debug, opt, etc.)
1335    SConscript('src/SConscript', variant_dir = variant_path, exports = 'env')
1336
1337def pairwise(iterable):
1338    "s -> (s0,s1), (s1,s2), (s2, s3), ..."
1339    a, b = itertools.tee(iterable)
1340    b.next()
1341    return itertools.izip(a, b)
1342
1343# Create false dependencies so SCons will parse ISAs, establish
1344# dependencies, and setup the build Environments serially. Either
1345# SCons (likely) and/or our SConscripts (possibly) cannot cope with -j
1346# greater than 1. It appears to be standard race condition stuff; it
1347# doesn't always fail, but usually, and the behaviors are different.
1348# Every time I tried to remove this, builds would fail in some
1349# creative new way. So, don't do that. You'll want to, though, because
1350# tests/SConscript takes a long time to make its Environments.
1351for t1, t2 in pairwise(sorted(all_isa_deps.iterkeys())):
1352    main.Depends('#%s-deps'     % t2, '#%s-deps'     % t1)
1353    main.Depends('#%s-environs' % t2, '#%s-environs' % t1)
1354
1355# base help text
1356Help('''
1357Usage: scons [scons options] [build variables] [target(s)]
1358
1359Extra scons options:
1360%(options)s
1361
1362Global build variables:
1363%(global_vars)s
1364
1365%(local_vars)s
1366''' % help_texts)
1367