SConstruct revision 11212:47e2adf7fb1a
1# -*- mode:python -*-
2
3# Copyright (c) 2013, 2015 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('--with-cxx-config', dest='with_cxx_config',
177               action='store_true',
178               help="Build with support for C++-based configuration")
179AddLocalOption('--default', dest='default', type='string', action='store',
180               help='Override which build_opts file to use for defaults')
181AddLocalOption('--ignore-style', dest='ignore_style', action='store_true',
182               help='Disable style checking hooks')
183AddLocalOption('--no-lto', dest='no_lto', action='store_true',
184               help='Disable Link-Time Optimization for fast')
185AddLocalOption('--update-ref', dest='update_ref', action='store_true',
186               help='Update test reference outputs')
187AddLocalOption('--verbose', dest='verbose', action='store_true',
188               help='Print full tool command lines')
189AddLocalOption('--without-python', dest='without_python',
190               action='store_true',
191               help='Build without Python configuration support')
192AddLocalOption('--without-tcmalloc', dest='without_tcmalloc',
193               action='store_true',
194               help='Disable linking against tcmalloc')
195AddLocalOption('--with-ubsan', dest='with_ubsan', action='store_true',
196               help='Build with Undefined Behavior Sanitizer if available')
197
198termcap = get_termcap(GetOption('use_colors'))
199
200########################################################################
201#
202# Set up the main build environment.
203#
204########################################################################
205
206# export TERM so that clang reports errors in color
207use_vars = set([ 'AS', 'AR', 'CC', 'CXX', 'HOME', 'LD_LIBRARY_PATH',
208                 'LIBRARY_PATH', 'PATH', 'PKG_CONFIG_PATH', 'PROTOC',
209                 'PYTHONPATH', 'RANLIB', 'SWIG', 'TERM' ])
210
211use_prefixes = [
212    "CCACHE_",         # ccache (caching compiler wrapper) configuration
213    "CCC_",            # clang static analyzer configuration
214    "DISTCC_",         # distcc (distributed compiler wrapper) configuration
215    "INCLUDE_SERVER_", # distcc pump server settings
216    "M5",              # M5 configuration (e.g., path to kernels)
217    ]
218
219use_env = {}
220for key,val in sorted(os.environ.iteritems()):
221    if key in use_vars or \
222            any([key.startswith(prefix) for prefix in use_prefixes]):
223        use_env[key] = val
224
225# Tell scons to avoid implicit command dependencies to avoid issues
226# with the param wrappes being compiled twice (see
227# http://scons.tigris.org/issues/show_bug.cgi?id=2811)
228main = Environment(ENV=use_env, IMPLICIT_COMMAND_DEPENDENCIES=0)
229main.Decider('MD5-timestamp')
230main.root = Dir(".")         # The current directory (where this file lives).
231main.srcdir = Dir("src")     # The source directory
232
233main_dict_keys = main.Dictionary().keys()
234
235# Check that we have a C/C++ compiler
236if not ('CC' in main_dict_keys and 'CXX' in main_dict_keys):
237    print "No C++ compiler installed (package g++ on Ubuntu and RedHat)"
238    Exit(1)
239
240# Check that swig is present
241if not 'SWIG' in main_dict_keys:
242    print "swig is not installed (package swig on Ubuntu and RedHat)"
243    Exit(1)
244
245# add useful python code PYTHONPATH so it can be used by subprocesses
246# as well
247main.AppendENVPath('PYTHONPATH', extra_python_paths)
248
249########################################################################
250#
251# Mercurial Stuff.
252#
253# If the gem5 directory is a mercurial repository, we should do some
254# extra things.
255#
256########################################################################
257
258hgdir = main.root.Dir(".hg")
259
260mercurial_style_message = """
261You're missing the gem5 style hook, which automatically checks your code
262against the gem5 style rules on hg commit and qrefresh commands.  This
263script will now install the hook in your .hg/hgrc file.
264Press enter to continue, or ctrl-c to abort: """
265
266mercurial_style_hook = """
267# The following lines were automatically added by gem5/SConstruct
268# to provide the gem5 style-checking hooks
269[extensions]
270style = %s/util/style.py
271
272[hooks]
273pretxncommit.style = python:style.check_style
274pre-qrefresh.style = python:style.check_style
275# End of SConstruct additions
276
277""" % (main.root.abspath)
278
279mercurial_lib_not_found = """
280Mercurial libraries cannot be found, ignoring style hook.  If
281you are a gem5 developer, please fix this and run the style
282hook. It is important.
283"""
284
285# Check for style hook and prompt for installation if it's not there.
286# Skip this if --ignore-style was specified, there's no .hg dir to
287# install a hook in, or there's no interactive terminal to prompt.
288if not GetOption('ignore_style') and hgdir.exists() and sys.stdin.isatty():
289    style_hook = True
290    try:
291        from mercurial import ui
292        ui = ui.ui()
293        ui.readconfig(hgdir.File('hgrc').abspath)
294        style_hook = ui.config('hooks', 'pretxncommit.style', None) and \
295                     ui.config('hooks', 'pre-qrefresh.style', None)
296    except ImportError:
297        print mercurial_lib_not_found
298
299    if not style_hook:
300        print mercurial_style_message,
301        # continue unless user does ctrl-c/ctrl-d etc.
302        try:
303            raw_input()
304        except:
305            print "Input exception, exiting scons.\n"
306            sys.exit(1)
307        hgrc_path = '%s/.hg/hgrc' % main.root.abspath
308        print "Adding style hook to", hgrc_path, "\n"
309        try:
310            hgrc = open(hgrc_path, 'a')
311            hgrc.write(mercurial_style_hook)
312            hgrc.close()
313        except:
314            print "Error updating", hgrc_path
315            sys.exit(1)
316
317
318###################################################
319#
320# Figure out which configurations to set up based on the path(s) of
321# the target(s).
322#
323###################################################
324
325# Find default configuration & binary.
326Default(environ.get('M5_DEFAULT_BINARY', 'build/ALPHA/gem5.debug'))
327
328# helper function: find last occurrence of element in list
329def rfind(l, elt, offs = -1):
330    for i in range(len(l)+offs, 0, -1):
331        if l[i] == elt:
332            return i
333    raise ValueError, "element not found"
334
335# Take a list of paths (or SCons Nodes) and return a list with all
336# paths made absolute and ~-expanded.  Paths will be interpreted
337# relative to the launch directory unless a different root is provided
338def makePathListAbsolute(path_list, root=GetLaunchDir()):
339    return [abspath(joinpath(root, expanduser(str(p))))
340            for p in path_list]
341
342# Each target must have 'build' in the interior of the path; the
343# directory below this will determine the build parameters.  For
344# example, for target 'foo/bar/build/ALPHA_SE/arch/alpha/blah.do' we
345# recognize that ALPHA_SE specifies the configuration because it
346# follow 'build' in the build path.
347
348# The funky assignment to "[:]" is needed to replace the list contents
349# in place rather than reassign the symbol to a new list, which
350# doesn't work (obviously!).
351BUILD_TARGETS[:] = makePathListAbsolute(BUILD_TARGETS)
352
353# Generate a list of the unique build roots and configs that the
354# collected targets reference.
355variant_paths = []
356build_root = None
357for t in BUILD_TARGETS:
358    path_dirs = t.split('/')
359    try:
360        build_top = rfind(path_dirs, 'build', -2)
361    except:
362        print "Error: no non-leaf 'build' dir found on target path", t
363        Exit(1)
364    this_build_root = joinpath('/',*path_dirs[:build_top+1])
365    if not build_root:
366        build_root = this_build_root
367    else:
368        if this_build_root != build_root:
369            print "Error: build targets not under same build root\n"\
370                  "  %s\n  %s" % (build_root, this_build_root)
371            Exit(1)
372    variant_path = joinpath('/',*path_dirs[:build_top+2])
373    if variant_path not in variant_paths:
374        variant_paths.append(variant_path)
375
376# Make sure build_root exists (might not if this is the first build there)
377if not isdir(build_root):
378    mkdir(build_root)
379main['BUILDROOT'] = build_root
380
381Export('main')
382
383main.SConsignFile(joinpath(build_root, "sconsign"))
384
385# Default duplicate option is to use hard links, but this messes up
386# when you use emacs to edit a file in the target dir, as emacs moves
387# file to file~ then copies to file, breaking the link.  Symbolic
388# (soft) links work better.
389main.SetOption('duplicate', 'soft-copy')
390
391#
392# Set up global sticky variables... these are common to an entire build
393# tree (not specific to a particular build like ALPHA_SE)
394#
395
396global_vars_file = joinpath(build_root, 'variables.global')
397
398global_vars = Variables(global_vars_file, args=ARGUMENTS)
399
400global_vars.AddVariables(
401    ('CC', 'C compiler', environ.get('CC', main['CC'])),
402    ('CXX', 'C++ compiler', environ.get('CXX', main['CXX'])),
403    ('SWIG', 'SWIG tool', environ.get('SWIG', main['SWIG'])),
404    ('PROTOC', 'protoc tool', environ.get('PROTOC', 'protoc')),
405    ('BATCH', 'Use batch pool for build and tests', False),
406    ('BATCH_CMD', 'Batch pool submission command name', 'qdo'),
407    ('M5_BUILD_CACHE', 'Cache built objects in this directory', False),
408    ('EXTRAS', 'Add extra directories to the compilation', '')
409    )
410
411# Update main environment with values from ARGUMENTS & global_vars_file
412global_vars.Update(main)
413help_texts["global_vars"] += global_vars.GenerateHelpText(main)
414
415# Save sticky variable settings back to current variables file
416global_vars.Save(global_vars_file, main)
417
418# Parse EXTRAS variable to build list of all directories where we're
419# look for sources etc.  This list is exported as extras_dir_list.
420base_dir = main.srcdir.abspath
421if main['EXTRAS']:
422    extras_dir_list = makePathListAbsolute(main['EXTRAS'].split(':'))
423else:
424    extras_dir_list = []
425
426Export('base_dir')
427Export('extras_dir_list')
428
429# the ext directory should be on the #includes path
430main.Append(CPPPATH=[Dir('ext')])
431
432def strip_build_path(path, env):
433    path = str(path)
434    variant_base = env['BUILDROOT'] + os.path.sep
435    if path.startswith(variant_base):
436        path = path[len(variant_base):]
437    elif path.startswith('build/'):
438        path = path[6:]
439    return path
440
441# Generate a string of the form:
442#   common/path/prefix/src1, src2 -> tgt1, tgt2
443# to print while building.
444class Transform(object):
445    # all specific color settings should be here and nowhere else
446    tool_color = termcap.Normal
447    pfx_color = termcap.Yellow
448    srcs_color = termcap.Yellow + termcap.Bold
449    arrow_color = termcap.Blue + termcap.Bold
450    tgts_color = termcap.Yellow + termcap.Bold
451
452    def __init__(self, tool, max_sources=99):
453        self.format = self.tool_color + (" [%8s] " % tool) \
454                      + self.pfx_color + "%s" \
455                      + self.srcs_color + "%s" \
456                      + self.arrow_color + " -> " \
457                      + self.tgts_color + "%s" \
458                      + termcap.Normal
459        self.max_sources = max_sources
460
461    def __call__(self, target, source, env, for_signature=None):
462        # truncate source list according to max_sources param
463        source = source[0:self.max_sources]
464        def strip(f):
465            return strip_build_path(str(f), env)
466        if len(source) > 0:
467            srcs = map(strip, source)
468        else:
469            srcs = ['']
470        tgts = map(strip, target)
471        # surprisingly, os.path.commonprefix is a dumb char-by-char string
472        # operation that has nothing to do with paths.
473        com_pfx = os.path.commonprefix(srcs + tgts)
474        com_pfx_len = len(com_pfx)
475        if com_pfx:
476            # do some cleanup and sanity checking on common prefix
477            if com_pfx[-1] == ".":
478                # prefix matches all but file extension: ok
479                # back up one to change 'foo.cc -> o' to 'foo.cc -> .o'
480                com_pfx = com_pfx[0:-1]
481            elif com_pfx[-1] == "/":
482                # common prefix is directory path: OK
483                pass
484            else:
485                src0_len = len(srcs[0])
486                tgt0_len = len(tgts[0])
487                if src0_len == com_pfx_len:
488                    # source is a substring of target, OK
489                    pass
490                elif tgt0_len == com_pfx_len:
491                    # target is a substring of source, need to back up to
492                    # avoid empty string on RHS of arrow
493                    sep_idx = com_pfx.rfind(".")
494                    if sep_idx != -1:
495                        com_pfx = com_pfx[0:sep_idx]
496                    else:
497                        com_pfx = ''
498                elif src0_len > com_pfx_len and srcs[0][com_pfx_len] == ".":
499                    # still splitting at file extension: ok
500                    pass
501                else:
502                    # probably a fluke; ignore it
503                    com_pfx = ''
504        # recalculate length in case com_pfx was modified
505        com_pfx_len = len(com_pfx)
506        def fmt(files):
507            f = map(lambda s: s[com_pfx_len:], files)
508            return ', '.join(f)
509        return self.format % (com_pfx, fmt(srcs), fmt(tgts))
510
511Export('Transform')
512
513# enable the regression script to use the termcap
514main['TERMCAP'] = termcap
515
516if GetOption('verbose'):
517    def MakeAction(action, string, *args, **kwargs):
518        return Action(action, *args, **kwargs)
519else:
520    MakeAction = Action
521    main['CCCOMSTR']        = Transform("CC")
522    main['CXXCOMSTR']       = Transform("CXX")
523    main['ASCOMSTR']        = Transform("AS")
524    main['SWIGCOMSTR']      = Transform("SWIG")
525    main['ARCOMSTR']        = Transform("AR", 0)
526    main['LINKCOMSTR']      = Transform("LINK", 0)
527    main['RANLIBCOMSTR']    = Transform("RANLIB", 0)
528    main['M4COMSTR']        = Transform("M4")
529    main['SHCCCOMSTR']      = Transform("SHCC")
530    main['SHCXXCOMSTR']     = Transform("SHCXX")
531Export('MakeAction')
532
533# Initialize the Link-Time Optimization (LTO) flags
534main['LTO_CCFLAGS'] = []
535main['LTO_LDFLAGS'] = []
536
537# According to the readme, tcmalloc works best if the compiler doesn't
538# assume that we're using the builtin malloc and friends. These flags
539# are compiler-specific, so we need to set them after we detect which
540# compiler we're using.
541main['TCMALLOC_CCFLAGS'] = []
542
543CXX_version = readCommand([main['CXX'],'--version'], exception=False)
544CXX_V = readCommand([main['CXX'],'-V'], exception=False)
545
546main['GCC'] = CXX_version and CXX_version.find('g++') >= 0
547main['CLANG'] = CXX_version and CXX_version.find('clang') >= 0
548if main['GCC'] + main['CLANG'] > 1:
549    print 'Error: How can we have two at the same time?'
550    Exit(1)
551
552# Set up default C++ compiler flags
553if main['GCC'] or main['CLANG']:
554    # As gcc and clang share many flags, do the common parts here
555    main.Append(CCFLAGS=['-pipe'])
556    main.Append(CCFLAGS=['-fno-strict-aliasing'])
557    # Enable -Wall and then disable the few warnings that we
558    # consistently violate
559    main.Append(CCFLAGS=['-Wall', '-Wno-sign-compare', '-Wundef'])
560    # We always compile using C++11
561    main.Append(CXXFLAGS=['-std=c++11'])
562    # Add selected sanity checks from -Wextra
563    main.Append(CXXFLAGS=['-Wmissing-field-initializers',
564                          '-Woverloaded-virtual'])
565else:
566    print termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal,
567    print "Don't know what compiler options to use for your compiler."
568    print termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX']
569    print termcap.Yellow + '       version:' + termcap.Normal,
570    if not CXX_version:
571        print termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +\
572               termcap.Normal
573    else:
574        print CXX_version.replace('\n', '<nl>')
575    print "       If you're trying to use a compiler other than GCC"
576    print "       or clang, there appears to be something wrong with your"
577    print "       environment."
578    print "       "
579    print "       If you are trying to use a compiler other than those listed"
580    print "       above you will need to ease fix SConstruct and "
581    print "       src/SConscript to support that compiler."
582    Exit(1)
583
584if main['GCC']:
585    # Check for a supported version of gcc. >= 4.7 is chosen for its
586    # level of c++11 support. See
587    # http://gcc.gnu.org/projects/cxx0x.html for details.
588    gcc_version = readCommand([main['CXX'], '-dumpversion'], exception=False)
589    if compareVersions(gcc_version, "4.7") < 0:
590        print 'Error: gcc version 4.7 or newer required.'
591        print '       Installed version:', gcc_version
592        Exit(1)
593
594    main['GCC_VERSION'] = gcc_version
595
596    # gcc from version 4.8 and above generates "rep; ret" instructions
597    # to avoid performance penalties on certain AMD chips. Older
598    # assemblers detect this as an error, "Error: expecting string
599    # instruction after `rep'"
600    if compareVersions(gcc_version, "4.8") > 0:
601        as_version_raw = readCommand([main['AS'], '-v', '/dev/null'],
602                                     exception=False).split()
603
604        # version strings may contain extra distro-specific
605        # qualifiers, so play it safe and keep only what comes before
606        # the first hyphen
607        as_version = as_version_raw[-1].split('-')[0] if as_version_raw \
608            else None
609
610        if not as_version or compareVersions(as_version, "2.23") < 0:
611            print termcap.Yellow + termcap.Bold + \
612                'Warning: This combination of gcc and binutils have' + \
613                ' known incompatibilities.\n' + \
614                '         If you encounter build problems, please update ' + \
615                'binutils to 2.23.' + \
616                termcap.Normal
617
618    # Make sure we warn if the user has requested to compile with the
619    # Undefined Benahvior Sanitizer and this version of gcc does not
620    # support it.
621    if GetOption('with_ubsan') and \
622            compareVersions(gcc_version, '4.9') < 0:
623        print termcap.Yellow + termcap.Bold + \
624            'Warning: UBSan is only supported using gcc 4.9 and later.' + \
625            termcap.Normal
626
627    # Add the appropriate Link-Time Optimization (LTO) flags
628    # unless LTO is explicitly turned off. Note that these flags
629    # are only used by the fast target.
630    if not GetOption('no_lto'):
631        # Pass the LTO flag when compiling to produce GIMPLE
632        # output, we merely create the flags here and only append
633        # them later
634        main['LTO_CCFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
635
636        # Use the same amount of jobs for LTO as we are running
637        # scons with
638        main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs')]
639
640    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc',
641                                  '-fno-builtin-realloc', '-fno-builtin-free'])
642
643elif main['CLANG']:
644    # Check for a supported version of clang, >= 3.1 is needed to
645    # support similar features as gcc 4.7. See
646    # http://clang.llvm.org/cxx_status.html for details
647    clang_version_re = re.compile(".* version (\d+\.\d+)")
648    clang_version_match = clang_version_re.search(CXX_version)
649    if (clang_version_match):
650        clang_version = clang_version_match.groups()[0]
651        if compareVersions(clang_version, "3.1") < 0:
652            print 'Error: clang version 3.1 or newer required.'
653            print '       Installed version:', clang_version
654            Exit(1)
655    else:
656        print 'Error: Unable to determine clang version.'
657        Exit(1)
658
659    # clang has a few additional warnings that we disable,
660    # tautological comparisons are allowed due to unsigned integers
661    # being compared to constants that happen to be 0, and extraneous
662    # parantheses are allowed due to Ruby's printing of the AST,
663    # finally self assignments are allowed as the generated CPU code
664    # is relying on this
665    main.Append(CCFLAGS=['-Wno-tautological-compare',
666                         '-Wno-parentheses',
667                         '-Wno-self-assign',
668                         # Some versions of libstdc++ (4.8?) seem to
669                         # use struct hash and class hash
670                         # interchangeably.
671                         '-Wno-mismatched-tags',
672                         ])
673
674    main.Append(TCMALLOC_CCFLAGS=['-fno-builtin'])
675
676    # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as
677    # opposed to libstdc++, as the later is dated.
678    if sys.platform == "darwin":
679        main.Append(CXXFLAGS=['-stdlib=libc++'])
680        main.Append(LIBS=['c++'])
681
682else:
683    print termcap.Yellow + termcap.Bold + 'Error' + termcap.Normal,
684    print "Don't know what compiler options to use for your compiler."
685    print termcap.Yellow + '       compiler:' + termcap.Normal, main['CXX']
686    print termcap.Yellow + '       version:' + termcap.Normal,
687    if not CXX_version:
688        print termcap.Yellow + termcap.Bold + "COMMAND NOT FOUND!" +\
689               termcap.Normal
690    else:
691        print CXX_version.replace('\n', '<nl>')
692    print "       If you're trying to use a compiler other than GCC"
693    print "       or clang, there appears to be something wrong with your"
694    print "       environment."
695    print "       "
696    print "       If you are trying to use a compiler other than those listed"
697    print "       above you will need to ease fix SConstruct and "
698    print "       src/SConscript to support that compiler."
699    Exit(1)
700
701# Set up common yacc/bison flags (needed for Ruby)
702main['YACCFLAGS'] = '-d'
703main['YACCHXXFILESUFFIX'] = '.hh'
704
705# Do this after we save setting back, or else we'll tack on an
706# extra 'qdo' every time we run scons.
707if main['BATCH']:
708    main['CC']     = main['BATCH_CMD'] + ' ' + main['CC']
709    main['CXX']    = main['BATCH_CMD'] + ' ' + main['CXX']
710    main['AS']     = main['BATCH_CMD'] + ' ' + main['AS']
711    main['AR']     = main['BATCH_CMD'] + ' ' + main['AR']
712    main['RANLIB'] = main['BATCH_CMD'] + ' ' + main['RANLIB']
713
714if sys.platform == 'cygwin':
715    # cygwin has some header file issues...
716    main.Append(CCFLAGS=["-Wno-uninitialized"])
717
718# Check for the protobuf compiler
719protoc_version = readCommand([main['PROTOC'], '--version'],
720                             exception='').split()
721
722# First two words should be "libprotoc x.y.z"
723if len(protoc_version) < 2 or protoc_version[0] != 'libprotoc':
724    print termcap.Yellow + termcap.Bold + \
725        'Warning: Protocol buffer compiler (protoc) not found.\n' + \
726        '         Please install protobuf-compiler for tracing support.' + \
727        termcap.Normal
728    main['PROTOC'] = False
729else:
730    # Based on the availability of the compress stream wrappers,
731    # require 2.1.0
732    min_protoc_version = '2.1.0'
733    if compareVersions(protoc_version[1], min_protoc_version) < 0:
734        print termcap.Yellow + termcap.Bold + \
735            'Warning: protoc version', min_protoc_version, \
736            'or newer required.\n' + \
737            '         Installed version:', protoc_version[1], \
738            termcap.Normal
739        main['PROTOC'] = False
740    else:
741        # Attempt to determine the appropriate include path and
742        # library path using pkg-config, that means we also need to
743        # check for pkg-config. Note that it is possible to use
744        # protobuf without the involvement of pkg-config. Later on we
745        # check go a library config check and at that point the test
746        # will fail if libprotobuf cannot be found.
747        if readCommand(['pkg-config', '--version'], exception=''):
748            try:
749                # Attempt to establish what linking flags to add for protobuf
750                # using pkg-config
751                main.ParseConfig('pkg-config --cflags --libs-only-L protobuf')
752            except:
753                print termcap.Yellow + termcap.Bold + \
754                    'Warning: pkg-config could not get protobuf flags.' + \
755                    termcap.Normal
756
757# Check for SWIG
758if not main.has_key('SWIG'):
759    print 'Error: SWIG utility not found.'
760    print '       Please install (see http://www.swig.org) and retry.'
761    Exit(1)
762
763# Check for appropriate SWIG version
764swig_version = readCommand([main['SWIG'], '-version'], exception='').split()
765# First 3 words should be "SWIG Version x.y.z"
766if len(swig_version) < 3 or \
767        swig_version[0] != 'SWIG' or swig_version[1] != 'Version':
768    print 'Error determining SWIG version.'
769    Exit(1)
770
771min_swig_version = '2.0.4'
772if compareVersions(swig_version[2], min_swig_version) < 0:
773    print 'Error: SWIG version', min_swig_version, 'or newer required.'
774    print '       Installed version:', swig_version[2]
775    Exit(1)
776
777# Check for known incompatibilities. The standard library shipped with
778# gcc >= 4.9 does not play well with swig versions prior to 3.0
779if main['GCC'] and compareVersions(gcc_version, '4.9') >= 0 and \
780        compareVersions(swig_version[2], '3.0') < 0:
781    print termcap.Yellow + termcap.Bold + \
782        'Warning: This combination of gcc and swig have' + \
783        ' known incompatibilities.\n' + \
784        '         If you encounter build problems, please update ' + \
785        'swig to 3.0 or later.' + \
786        termcap.Normal
787
788# Set up SWIG flags & scanner
789swig_flags=Split('-c++ -python -modern -templatereduce $_CPPINCFLAGS')
790main.Append(SWIGFLAGS=swig_flags)
791
792# Check for 'timeout' from GNU coreutils. If present, regressions will
793# be run with a time limit. We require version 8.13 since we rely on
794# support for the '--foreground' option.
795timeout_lines = readCommand(['timeout', '--version'],
796                            exception='').splitlines()
797# Get the first line and tokenize it
798timeout_version = timeout_lines[0].split() if timeout_lines else []
799main['TIMEOUT'] =  timeout_version and \
800    compareVersions(timeout_version[-1], '8.13') >= 0
801
802# filter out all existing swig scanners, they mess up the dependency
803# stuff for some reason
804scanners = []
805for scanner in main['SCANNERS']:
806    skeys = scanner.skeys
807    if skeys == '.i':
808        continue
809
810    if isinstance(skeys, (list, tuple)) and '.i' in skeys:
811        continue
812
813    scanners.append(scanner)
814
815# add the new swig scanner that we like better
816from SCons.Scanner import ClassicCPP as CPPScanner
817swig_inc_re = '^[ \t]*[%,#][ \t]*(?:include|import)[ \t]*(<|")([^>"]+)(>|")'
818scanners.append(CPPScanner("SwigScan", [ ".i" ], "CPPPATH", swig_inc_re))
819
820# replace the scanners list that has what we want
821main['SCANNERS'] = scanners
822
823# Add a custom Check function to test for structure members.
824def CheckMember(context, include, decl, member, include_quotes="<>"):
825    context.Message("Checking for member %s in %s..." %
826                    (member, decl))
827    text = """
828#include %(header)s
829int main(){
830  %(decl)s test;
831  (void)test.%(member)s;
832  return 0;
833};
834""" % { "header" : include_quotes[0] + include + include_quotes[1],
835        "decl" : decl,
836        "member" : member,
837        }
838
839    ret = context.TryCompile(text, extension=".cc")
840    context.Result(ret)
841    return ret
842
843# Platform-specific configuration.  Note again that we assume that all
844# builds under a given build root run on the same host platform.
845conf = Configure(main,
846                 conf_dir = joinpath(build_root, '.scons_config'),
847                 log_file = joinpath(build_root, 'scons_config.log'),
848                 custom_tests = {
849        'CheckMember' : CheckMember,
850        })
851
852# Check if we should compile a 64 bit binary on Mac OS X/Darwin
853try:
854    import platform
855    uname = platform.uname()
856    if uname[0] == 'Darwin' and compareVersions(uname[2], '9.0.0') >= 0:
857        if int(readCommand('sysctl -n hw.cpu64bit_capable')[0]):
858            main.Append(CCFLAGS=['-arch', 'x86_64'])
859            main.Append(CFLAGS=['-arch', 'x86_64'])
860            main.Append(LINKFLAGS=['-arch', 'x86_64'])
861            main.Append(ASFLAGS=['-arch', 'x86_64'])
862except:
863    pass
864
865# Recent versions of scons substitute a "Null" object for Configure()
866# when configuration isn't necessary, e.g., if the "--help" option is
867# present.  Unfortuantely this Null object always returns false,
868# breaking all our configuration checks.  We replace it with our own
869# more optimistic null object that returns True instead.
870if not conf:
871    def NullCheck(*args, **kwargs):
872        return True
873
874    class NullConf:
875        def __init__(self, env):
876            self.env = env
877        def Finish(self):
878            return self.env
879        def __getattr__(self, mname):
880            return NullCheck
881
882    conf = NullConf(main)
883
884# Cache build files in the supplied directory.
885if main['M5_BUILD_CACHE']:
886    print 'Using build cache located at', main['M5_BUILD_CACHE']
887    CacheDir(main['M5_BUILD_CACHE'])
888
889if not GetOption('without_python'):
890    # Find Python include and library directories for embedding the
891    # interpreter. We rely on python-config to resolve the appropriate
892    # includes and linker flags. ParseConfig does not seem to understand
893    # the more exotic linker flags such as -Xlinker and -export-dynamic so
894    # we add them explicitly below. If you want to link in an alternate
895    # version of python, see above for instructions on how to invoke
896    # scons with the appropriate PATH set.
897    #
898    # First we check if python2-config exists, else we use python-config
899    python_config = readCommand(['which', 'python2-config'],
900                                exception='').strip()
901    if not os.path.exists(python_config):
902        python_config = readCommand(['which', 'python-config'],
903                                    exception='').strip()
904    py_includes = readCommand([python_config, '--includes'],
905                              exception='').split()
906    # Strip the -I from the include folders before adding them to the
907    # CPPPATH
908    main.Append(CPPPATH=map(lambda inc: inc[2:], py_includes))
909
910    # Read the linker flags and split them into libraries and other link
911    # flags. The libraries are added later through the call the CheckLib.
912    py_ld_flags = readCommand([python_config, '--ldflags'],
913        exception='').split()
914    py_libs = []
915    for lib in py_ld_flags:
916         if not lib.startswith('-l'):
917             main.Append(LINKFLAGS=[lib])
918         else:
919             lib = lib[2:]
920             if lib not in py_libs:
921                 py_libs.append(lib)
922
923    # verify that this stuff works
924    if not conf.CheckHeader('Python.h', '<>'):
925        print "Error: can't find Python.h header in", py_includes
926        print "Install Python headers (package python-dev on Ubuntu and RedHat)"
927        Exit(1)
928
929    for lib in py_libs:
930        if not conf.CheckLib(lib):
931            print "Error: can't find library %s required by python" % lib
932            Exit(1)
933
934# On Solaris you need to use libsocket for socket ops
935if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
936   if not conf.CheckLibWithHeader('socket', 'sys/socket.h', 'C++', 'accept(0,0,0);'):
937       print "Can't find library with socket calls (e.g. accept())"
938       Exit(1)
939
940# Check for zlib.  If the check passes, libz will be automatically
941# added to the LIBS environment variable.
942if not conf.CheckLibWithHeader('z', 'zlib.h', 'C++','zlibVersion();'):
943    print 'Error: did not find needed zlib compression library '\
944          'and/or zlib.h header file.'
945    print '       Please install zlib and try again.'
946    Exit(1)
947
948# If we have the protobuf compiler, also make sure we have the
949# development libraries. If the check passes, libprotobuf will be
950# automatically added to the LIBS environment variable. After
951# this, we can use the HAVE_PROTOBUF flag to determine if we have
952# got both protoc and libprotobuf available.
953main['HAVE_PROTOBUF'] = main['PROTOC'] and \
954    conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
955                            'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
956
957# If we have the compiler but not the library, print another warning.
958if main['PROTOC'] and not main['HAVE_PROTOBUF']:
959    print termcap.Yellow + termcap.Bold + \
960        'Warning: did not find protocol buffer library and/or headers.\n' + \
961    '       Please install libprotobuf-dev for tracing support.' + \
962    termcap.Normal
963
964# Check for librt.
965have_posix_clock = \
966    conf.CheckLibWithHeader(None, 'time.h', 'C',
967                            'clock_nanosleep(0,0,NULL,NULL);') or \
968    conf.CheckLibWithHeader('rt', 'time.h', 'C',
969                            'clock_nanosleep(0,0,NULL,NULL);')
970
971have_posix_timers = \
972    conf.CheckLibWithHeader([None, 'rt'], [ 'time.h', 'signal.h' ], 'C',
973                            'timer_create(CLOCK_MONOTONIC, NULL, NULL);')
974
975if not GetOption('without_tcmalloc'):
976    if conf.CheckLib('tcmalloc'):
977        main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
978    elif conf.CheckLib('tcmalloc_minimal'):
979        main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS'])
980    else:
981        print termcap.Yellow + termcap.Bold + \
982              "You can get a 12% performance improvement by "\
983              "installing tcmalloc (libgoogle-perftools-dev package "\
984              "on Ubuntu or RedHat)." + termcap.Normal
985
986if not have_posix_clock:
987    print "Can't find library for POSIX clocks."
988
989# Check for <fenv.h> (C99 FP environment control)
990have_fenv = conf.CheckHeader('fenv.h', '<>')
991if not have_fenv:
992    print "Warning: Header file <fenv.h> not found."
993    print "         This host has no IEEE FP rounding mode control."
994
995# Check if we should enable KVM-based hardware virtualization. The API
996# we rely on exists since version 2.6.36 of the kernel, but somehow
997# the KVM_API_VERSION does not reflect the change. We test for one of
998# the types as a fall back.
999have_kvm = conf.CheckHeader('linux/kvm.h', '<>')
1000if not have_kvm:
1001    print "Info: Compatible header file <linux/kvm.h> not found, " \
1002        "disabling KVM support."
1003
1004# x86 needs support for xsave. We test for the structure here since we
1005# won't be able to run new tests by the time we know which ISA we're
1006# targeting.
1007have_kvm_xsave = conf.CheckTypeSize('struct kvm_xsave',
1008                                    '#include <linux/kvm.h>') != 0
1009
1010# Check if the requested target ISA is compatible with the host
1011def is_isa_kvm_compatible(isa):
1012    try:
1013        import platform
1014        host_isa = platform.machine()
1015    except:
1016        print "Warning: Failed to determine host ISA."
1017        return False
1018
1019    if not have_posix_timers:
1020        print "Warning: Can not enable KVM, host seems to lack support " \
1021            "for POSIX timers"
1022        return False
1023
1024    if isa == "arm":
1025        return host_isa in ( "armv7l", "aarch64" )
1026    elif isa == "x86":
1027        if host_isa != "x86_64":
1028            return False
1029
1030        if not have_kvm_xsave:
1031            print "KVM on x86 requires xsave support in kernel headers."
1032            return False
1033
1034        return True
1035    else:
1036        return False
1037
1038
1039# Check if the exclude_host attribute is available. We want this to
1040# get accurate instruction counts in KVM.
1041main['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
1042    'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
1043
1044
1045######################################################################
1046#
1047# Finish the configuration
1048#
1049main = conf.Finish()
1050
1051######################################################################
1052#
1053# Collect all non-global variables
1054#
1055
1056# Define the universe of supported ISAs
1057all_isa_list = [ ]
1058Export('all_isa_list')
1059
1060class CpuModel(object):
1061    '''The CpuModel class encapsulates everything the ISA parser needs to
1062    know about a particular CPU model.'''
1063
1064    # Dict of available CPU model objects.  Accessible as CpuModel.dict.
1065    dict = {}
1066
1067    # Constructor.  Automatically adds models to CpuModel.dict.
1068    def __init__(self, name, default=False):
1069        self.name = name           # name of model
1070
1071        # This cpu is enabled by default
1072        self.default = default
1073
1074        # Add self to dict
1075        if name in CpuModel.dict:
1076            raise AttributeError, "CpuModel '%s' already registered" % name
1077        CpuModel.dict[name] = self
1078
1079Export('CpuModel')
1080
1081# Sticky variables get saved in the variables file so they persist from
1082# one invocation to the next (unless overridden, in which case the new
1083# value becomes sticky).
1084sticky_vars = Variables(args=ARGUMENTS)
1085Export('sticky_vars')
1086
1087# Sticky variables that should be exported
1088export_vars = []
1089Export('export_vars')
1090
1091# For Ruby
1092all_protocols = []
1093Export('all_protocols')
1094protocol_dirs = []
1095Export('protocol_dirs')
1096slicc_includes = []
1097Export('slicc_includes')
1098
1099# Walk the tree and execute all SConsopts scripts that wil add to the
1100# above variables
1101if GetOption('verbose'):
1102    print "Reading SConsopts"
1103for bdir in [ base_dir ] + extras_dir_list:
1104    if not isdir(bdir):
1105        print "Error: directory '%s' does not exist" % bdir
1106        Exit(1)
1107    for root, dirs, files in os.walk(bdir):
1108        if 'SConsopts' in files:
1109            if GetOption('verbose'):
1110                print "Reading", joinpath(root, 'SConsopts')
1111            SConscript(joinpath(root, 'SConsopts'))
1112
1113all_isa_list.sort()
1114
1115sticky_vars.AddVariables(
1116    EnumVariable('TARGET_ISA', 'Target ISA', 'alpha', all_isa_list),
1117    ListVariable('CPU_MODELS', 'CPU models',
1118                 sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
1119                 sorted(CpuModel.dict.keys())),
1120    BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
1121                 False),
1122    BoolVariable('SS_COMPATIBLE_FP',
1123                 'Make floating-point results compatible with SimpleScalar',
1124                 False),
1125    BoolVariable('USE_SSE2',
1126                 'Compile for SSE2 (-msse2) to get IEEE FP on x86 hosts',
1127                 False),
1128    BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks', have_posix_clock),
1129    BoolVariable('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
1130    BoolVariable('CP_ANNOTATE', 'Enable critical path annotation capability', False),
1131    BoolVariable('USE_KVM', 'Enable hardware virtualized (KVM) CPU models', have_kvm),
1132    EnumVariable('PROTOCOL', 'Coherence protocol for Ruby', 'None',
1133                  all_protocols),
1134    )
1135
1136# These variables get exported to #defines in config/*.hh (see src/SConscript).
1137export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'CP_ANNOTATE',
1138                'USE_POSIX_CLOCK', 'USE_KVM', 'PROTOCOL', 'HAVE_PROTOBUF',
1139                'HAVE_PERF_ATTR_EXCLUDE_HOST']
1140
1141###################################################
1142#
1143# Define a SCons builder for configuration flag headers.
1144#
1145###################################################
1146
1147# This function generates a config header file that #defines the
1148# variable symbol to the current variable setting (0 or 1).  The source
1149# operands are the name of the variable and a Value node containing the
1150# value of the variable.
1151def build_config_file(target, source, env):
1152    (variable, value) = [s.get_contents() for s in source]
1153    f = file(str(target[0]), 'w')
1154    print >> f, '#define', variable, value
1155    f.close()
1156    return None
1157
1158# Combine the two functions into a scons Action object.
1159config_action = MakeAction(build_config_file, Transform("CONFIG H", 2))
1160
1161# The emitter munges the source & target node lists to reflect what
1162# we're really doing.
1163def config_emitter(target, source, env):
1164    # extract variable name from Builder arg
1165    variable = str(target[0])
1166    # True target is config header file
1167    target = joinpath('config', variable.lower() + '.hh')
1168    val = env[variable]
1169    if isinstance(val, bool):
1170        # Force value to 0/1
1171        val = int(val)
1172    elif isinstance(val, str):
1173        val = '"' + val + '"'
1174
1175    # Sources are variable name & value (packaged in SCons Value nodes)
1176    return ([target], [Value(variable), Value(val)])
1177
1178config_builder = Builder(emitter = config_emitter, action = config_action)
1179
1180main.Append(BUILDERS = { 'ConfigFile' : config_builder })
1181
1182# libelf build is shared across all configs in the build root.
1183main.SConscript('ext/libelf/SConscript',
1184                variant_dir = joinpath(build_root, 'libelf'))
1185
1186# gzstream build is shared across all configs in the build root.
1187main.SConscript('ext/gzstream/SConscript',
1188                variant_dir = joinpath(build_root, 'gzstream'))
1189
1190# libfdt build is shared across all configs in the build root.
1191main.SConscript('ext/libfdt/SConscript',
1192                variant_dir = joinpath(build_root, 'libfdt'))
1193
1194# fputils build is shared across all configs in the build root.
1195main.SConscript('ext/fputils/SConscript',
1196                variant_dir = joinpath(build_root, 'fputils'))
1197
1198# DRAMSim2 build is shared across all configs in the build root.
1199main.SConscript('ext/dramsim2/SConscript',
1200                variant_dir = joinpath(build_root, 'dramsim2'))
1201
1202# DRAMPower build is shared across all configs in the build root.
1203main.SConscript('ext/drampower/SConscript',
1204                variant_dir = joinpath(build_root, 'drampower'))
1205
1206# nomali build is shared across all configs in the build root.
1207main.SConscript('ext/nomali/SConscript',
1208                variant_dir = joinpath(build_root, 'nomali'))
1209
1210###################################################
1211#
1212# This function is used to set up a directory with switching headers
1213#
1214###################################################
1215
1216main['ALL_ISA_LIST'] = all_isa_list
1217all_isa_deps = {}
1218def make_switching_dir(dname, switch_headers, env):
1219    # Generate the header.  target[0] is the full path of the output
1220    # header to generate.  'source' is a dummy variable, since we get the
1221    # list of ISAs from env['ALL_ISA_LIST'].
1222    def gen_switch_hdr(target, source, env):
1223        fname = str(target[0])
1224        isa = env['TARGET_ISA'].lower()
1225        try:
1226            f = open(fname, 'w')
1227            print >>f, '#include "%s/%s/%s"' % (dname, isa, basename(fname))
1228            f.close()
1229        except IOError:
1230            print "Failed to create %s" % fname
1231            raise
1232
1233    # Build SCons Action object. 'varlist' specifies env vars that this
1234    # action depends on; when env['ALL_ISA_LIST'] changes these actions
1235    # should get re-executed.
1236    switch_hdr_action = MakeAction(gen_switch_hdr,
1237                          Transform("GENERATE"), varlist=['ALL_ISA_LIST'])
1238
1239    # Instantiate actions for each header
1240    for hdr in switch_headers:
1241        env.Command(hdr, [], switch_hdr_action)
1242
1243    isa_target = Dir('.').up().name.lower().replace('_', '-')
1244    env['PHONY_BASE'] = '#'+isa_target
1245    all_isa_deps[isa_target] = None
1246
1247Export('make_switching_dir')
1248
1249# all-isas -> all-deps -> all-environs -> all_targets
1250main.Alias('#all-isas', [])
1251main.Alias('#all-deps', '#all-isas')
1252
1253# Dummy target to ensure all environments are created before telling
1254# SCons what to actually make (the command line arguments).  We attach
1255# them to the dependence graph after the environments are complete.
1256ORIG_BUILD_TARGETS = list(BUILD_TARGETS) # force a copy; gets closure to work.
1257def environsComplete(target, source, env):
1258    for t in ORIG_BUILD_TARGETS:
1259        main.Depends('#all-targets', t)
1260
1261# Each build/* switching_dir attaches its *-environs target to #all-environs.
1262main.Append(BUILDERS = {'CompleteEnvirons' :
1263                        Builder(action=MakeAction(environsComplete, None))})
1264main.CompleteEnvirons('#all-environs', [])
1265
1266def doNothing(**ignored): pass
1267main.Append(BUILDERS = {'Dummy': Builder(action=MakeAction(doNothing, None))})
1268
1269# The final target to which all the original targets ultimately get attached.
1270main.Dummy('#all-targets', '#all-environs')
1271BUILD_TARGETS[:] = ['#all-targets']
1272
1273###################################################
1274#
1275# Define build environments for selected configurations.
1276#
1277###################################################
1278
1279for variant_path in variant_paths:
1280    if not GetOption('silent'):
1281        print "Building in", variant_path
1282
1283    # Make a copy of the build-root environment to use for this config.
1284    env = main.Clone()
1285    env['BUILDDIR'] = variant_path
1286
1287    # variant_dir is the tail component of build path, and is used to
1288    # determine the build parameters (e.g., 'ALPHA_SE')
1289    (build_root, variant_dir) = splitpath(variant_path)
1290
1291    # Set env variables according to the build directory config.
1292    sticky_vars.files = []
1293    # Variables for $BUILD_ROOT/$VARIANT_DIR are stored in
1294    # $BUILD_ROOT/variables/$VARIANT_DIR so you can nuke
1295    # $BUILD_ROOT/$VARIANT_DIR without losing your variables settings.
1296    current_vars_file = joinpath(build_root, 'variables', variant_dir)
1297    if isfile(current_vars_file):
1298        sticky_vars.files.append(current_vars_file)
1299        if not GetOption('silent'):
1300            print "Using saved variables file %s" % current_vars_file
1301    else:
1302        # Build dir-specific variables file doesn't exist.
1303
1304        # Make sure the directory is there so we can create it later
1305        opt_dir = dirname(current_vars_file)
1306        if not isdir(opt_dir):
1307            mkdir(opt_dir)
1308
1309        # Get default build variables from source tree.  Variables are
1310        # normally determined by name of $VARIANT_DIR, but can be
1311        # overridden by '--default=' arg on command line.
1312        default = GetOption('default')
1313        opts_dir = joinpath(main.root.abspath, 'build_opts')
1314        if default:
1315            default_vars_files = [joinpath(build_root, 'variables', default),
1316                                  joinpath(opts_dir, default)]
1317        else:
1318            default_vars_files = [joinpath(opts_dir, variant_dir)]
1319        existing_files = filter(isfile, default_vars_files)
1320        if existing_files:
1321            default_vars_file = existing_files[0]
1322            sticky_vars.files.append(default_vars_file)
1323            print "Variables file %s not found,\n  using defaults in %s" \
1324                  % (current_vars_file, default_vars_file)
1325        else:
1326            print "Error: cannot find variables file %s or " \
1327                  "default file(s) %s" \
1328                  % (current_vars_file, ' or '.join(default_vars_files))
1329            Exit(1)
1330
1331    # Apply current variable settings to env
1332    sticky_vars.Update(env)
1333
1334    help_texts["local_vars"] += \
1335        "Build variables for %s:\n" % variant_dir \
1336                 + sticky_vars.GenerateHelpText(env)
1337
1338    # Process variable settings.
1339
1340    if not have_fenv and env['USE_FENV']:
1341        print "Warning: <fenv.h> not available; " \
1342              "forcing USE_FENV to False in", variant_dir + "."
1343        env['USE_FENV'] = False
1344
1345    if not env['USE_FENV']:
1346        print "Warning: No IEEE FP rounding mode control in", variant_dir + "."
1347        print "         FP results may deviate slightly from other platforms."
1348
1349    if env['EFENCE']:
1350        env.Append(LIBS=['efence'])
1351
1352    if env['USE_KVM']:
1353        if not have_kvm:
1354            print "Warning: Can not enable KVM, host seems to lack KVM support"
1355            env['USE_KVM'] = False
1356        elif not is_isa_kvm_compatible(env['TARGET_ISA']):
1357            print "Info: KVM support disabled due to unsupported host and " \
1358                "target ISA combination"
1359            env['USE_KVM'] = False
1360
1361    # Warn about missing optional functionality
1362    if env['USE_KVM']:
1363        if not main['HAVE_PERF_ATTR_EXCLUDE_HOST']:
1364            print "Warning: perf_event headers lack support for the " \
1365                "exclude_host attribute. KVM instruction counts will " \
1366                "be inaccurate."
1367
1368    # Save sticky variable settings back to current variables file
1369    sticky_vars.Save(current_vars_file, env)
1370
1371    if env['USE_SSE2']:
1372        env.Append(CCFLAGS=['-msse2'])
1373
1374    # The src/SConscript file sets up the build rules in 'env' according
1375    # to the configured variables.  It returns a list of environments,
1376    # one for each variant build (debug, opt, etc.)
1377    SConscript('src/SConscript', variant_dir = variant_path, exports = 'env')
1378
1379def pairwise(iterable):
1380    "s -> (s0,s1), (s1,s2), (s2, s3), ..."
1381    a, b = itertools.tee(iterable)
1382    b.next()
1383    return itertools.izip(a, b)
1384
1385# Create false dependencies so SCons will parse ISAs, establish
1386# dependencies, and setup the build Environments serially. Either
1387# SCons (likely) and/or our SConscripts (possibly) cannot cope with -j
1388# greater than 1. It appears to be standard race condition stuff; it
1389# doesn't always fail, but usually, and the behaviors are different.
1390# Every time I tried to remove this, builds would fail in some
1391# creative new way. So, don't do that. You'll want to, though, because
1392# tests/SConscript takes a long time to make its Environments.
1393for t1, t2 in pairwise(sorted(all_isa_deps.iterkeys())):
1394    main.Depends('#%s-deps'     % t2, '#%s-deps'     % t1)
1395    main.Depends('#%s-environs' % t2, '#%s-environs' % t1)
1396
1397# base help text
1398Help('''
1399Usage: scons [scons options] [build variables] [target(s)]
1400
1401Extra scons options:
1402%(options)s
1403
1404Global build variables:
1405%(global_vars)s
1406
1407%(local_vars)s
1408''' % help_texts)
1409