C++11 has support for static_asserts to provide compile-time assertion
checking. This is very useful when testing, for example, structure
sizes to make sure that the compiler got the right alignment or vector
sizes.
This patch adds a few more checks to ensure that a compiler is present
on the system, along with swig. It references the relevant packages on
Ubuntu/RedHat, and also adds a similar line for the Python headers.
This patch adds Link-Time Optimization when building the fast target
using gcc >= 4.6, and adds a scons flag to disable it (-no-lto). No
check is performed to guarantee that the linker supports LTO and use
of the linker plugin, so the user has to ensure that binutils GNU ld
>= 2.21 or the gold linker is available. Typically, if gcc >= 4.6 is
available, the latter should not be a problem. Currently the LTO
option is only useful for gcc >= 4.6, due to the limited support on
clang and earlier versions of gcc. The intention is to also add
support for clang once the LTO integration matures.
The same number of jobs is used for the parallel phase of LTO as the
jobs specified on the scons command line, using the -flto=n flag that
was introduced with gcc 4.6. The gold linker also supports concurrent
and incremental linking, but this is not used at this point.
The compilation and linking time is increased by almost 50% on
average, although ARM seems to be particularly demanding with an
increase of almost 100%. Also beware when using this as gcc uses a
tremendous amount of memory and temp space in the process. You have
been warned.
After some careful consideration, and plenty discussions, the flag is
only added to the fast target, and the warning that was issued in an
earlier version of this patch is now removed. Similarly, the flag used
to enable LTO, now the default is to use it, and the flag has been
modified to disable LTO. The rationale behind this decision is that
opt is used for development, whereas fast is only used for long runs,
e.g. regressions or more elaborate experiments where the additional
compile and link time is amortized by a much larger run time.
When it comes to the return on investment, the regression seems to be
roughly 15% faster with LTO. For a bit more detail, I ran twolf on
ARM.fast, with three repeated runs, and they all finish within 42
minutes (+- 25 seconds) without LTO and 31 minutes (+- 25 seconds)
with LTO, i.e. LTO gives an impressive >25% speed-up for this case.
Without LTO (ARM.fast twolf)
real 42m37.632s
user 42m34.448s
sys 0m0.390s
real 41m51.793s
user 41m50.384s
sys 0m0.131s
real 41m45.491s
user 41m39.791s
sys 0m0.139s
With LTO (ARM.fast twolf)
real 30m33.588s
user 30m5.701s
sys 0m0.141s
real 31m27.791s
user 31m24.674s
sys 0m0.111s
real 31m25.500s
user 31m16.731s
sys 0m0.106s
This patch shifts the version of gcc for which we enable c++0x from
4.6 to 4.4 The more long term plan is to see what the c++0x features
can bring and what level of support would be enabled simply by bumping
the required version of gcc from 4.3 to 4.4.
A few minor things had to be fixed in the code base, most notably the
choice of a hashmap implementation. In the Ruby Sequencer there were
also a few minor issues that gcc 4.4 was not too happy about.
This patch adds the LIBRARY_PATH from the users OS environment to
Scons build environment. This path is used when linking to search for
libraries, and this patch enables tcmalloc to be used during the build
even if it is not placed in the default search paths.
This patch updates the message printed if the user does not have
tcmalloc available. It turns out that the correct package (which
creates all required symlinks etc) is libgoogle-perftools-dev. This
has been verified on Ubuntu 12.04.
This package is available in Ubuntu, Debian, and Redhat as google-perftools.
With multiple tests on a single machine I've seen a little over 10% performance
gain with tcmalloc.
While FastAlloc provides a small performance increase (~1.5%) over regular malloc it isn't thread safe.
After removing FastAlloc and using tcmalloc I've seen a performance increase of 12% over libc malloc
when running twolf for ARM.
This patch adds a very basic pretty-printing of the test status
(passed or failed) to highlight failing tests even more: green for
passed, and red for failed. The printing only uses ANSI it the target
output is a tty and supports ANSI colours. Hence, any regression
scripts that are outputting to files or sending e-mails etc should
still be fine.
This patch addresses a number of minor issues that cause problems when
compiling with clang >= 3.0 and gcc >= 4.6. Most importantly, it
avoids using the deprecated ext/hash_map and instead uses
unordered_map (and similarly so for the hash_set). To make use of the
new STL containers, g++ and clang has to be invoked with "-std=c++0x",
and this is now added for all gcc versions >= 4.6, and for clang >=
3.0. For gcc >= 4.3 and <= 4.5 and clang <= 3.0 we use the tr1
unordered_map to avoid the deprecation warning.
The addition of c++0x in turn causes a few problems, as the
compiler is more stringent and adds a number of new warnings. Below,
the most important issues are enumerated:
1) the use of namespaces is more strict, e.g. for isnan, and all
headers opening the entire namespace std are now fixed.
2) another other issue caused by the more stringent compiler is the
narrowing of the embedded python, which used to be a char array,
and is now unsigned char since there were values larger than 128.
3) a particularly odd issue that arose with the new c++0x behaviour is
found in range.hh, where the operator< causes gcc to complain about
the template type parsing (the "<" is interpreted as the beginning
of a template argument), and the problem seems to be related to the
begin/end members introduced for the range-type iteration, which is
a new feature in c++11.
As a minor update, this patch also fixes the build flags for the clang
debug target that used to be shared with gcc and incorrectly use
"-ggdb".
Enables the CheckerCPU to be selected at runtime with the --checker option
from the configs/example/fs.py and configs/example/se.py configuration
files. Also merges with the SE/FS changes.
1. --implicit-cache behavior is default.
2. makeEnv in src/SConscript is conditionally called.
3. decider set to MD5-timestamp
4. NO_HTML build option changed to SLICC_HTML (defaults to False)
Got rid of gratuitous M5 reference in the function name.
In the process, wondered why we have this function at all and
spent time trying to get rid of it and eventually firgured out
why it's needed. Put the answer in a comment so we don't have
to wonder again.
This patch adds the necessary flags to the SConstruct and SConscript
files for compiling using clang 2.9 and later (on Ubuntu et al and OSX
XCode 4.2), and also cleans up a bunch of compiler warnings found by
clang. Most of the warnings are related to hidden virtual functions,
comparisons with unsigneds >= 0, and if-statements with empty
bodies. A number of mismatches between struct and class are also
fixed. clang 2.8 is not working as it has problems with class names
that occur in multiple namespaces (e.g. Statistics in
kernel_stats.hh).
clang has a bug (http://llvm.org/bugs/show_bug.cgi?id=7247) which
causes confusion between the container std::set and the function
Packet::set, and this is currently addressed by not including the
entire namespace std, but rather selecting e.g. "using std::vector" in
the appropriate places.
Adaptations to make gem5 compile and run on OSX 10.7.2, with a stock
gcc 4.2.1 and the remaining dependencies from macports, i.e. python
2.7,.2 swig 2.0.4, mercurial 2.0. The changes include an adaptation of
the SConstruct to handle non-library linker flags, and Darwin-specific
code to find the memory usage of gem5. A number of Ruby files relied
on ambigious uint (without the 32 suffix) which caused compilation
errors.
This patch replaces RUBY with PROTOCOL in all the SConscript files as
the environment variable that decides whether or not certain components
of the simulator are compiled.
This patch drops RUBY as a compile time option. Instead the PROTOCOL option
is used to figure out whether or not to build Ruby. If the specified protocol
is 'None', then Ruby is not compiled.
Seems easier than pestering people about it.
Note also that path is now absolute, so you don't get errors
when invoking hg from subdirectories.
Also whacked unused mercurial_bin_not_found message (the
code that used this was deleted a couple months ago in
rev 5138d1e453f1).
Make sure all command-line targets and EXTRAS directories
are interpreted relative to the launch directory. This
turns out to be very useful when building code from an
EXTRAS directory using SCons's -C option.
We were trying to do this with targets but it didn't actually
work since we didn't update BUILD_TARGETS (so SCons got
confused internally). We weren't even trying with EXTRAS.
To simplify the code, the default target is also interpreted
relative to the launch dir even though it was explicitly
handled as relative to the m5 dir before... I doubt anyone
really uses this anyway so it didn't seem worth the complexity.
(Maybe we should get rid of it?)
Currently the --default= option only looks at the predefined
build configs (in m5/build_opts), so you're limited to basing
a new build config off of those (ALPHA_SE, etc.). If you've
already defined a non-standard build config and want to clone
it or tweak it, you have to start from scratch. This patch
causes --default= to look first among the existing builds
(in build/variables) before looking in build_opts so you
can specify an existing non-standard build config as a
starting point for a new config.
FastAlloc's reuse policies can mask allocation bugs, so
we typically want it disabled when debugging. Set
FORCE_FAST_ALLOC to enable even when debugging, and set
NO_FAST_ALLOC to disable even in non-debug builds.
This causes a lot of rebuilds that could have otherwise possibly been
avoided, and, more annoyingly, a lot of unnecessary rerunning of the
regressions. The benefits of having the revision in the output haven't
materialized, so this change removes it.
The global sticky options were being printed with a heading, and then the
global nonsticky options were being printed immediately after them without a
heading. Because the two lists ran together and the first had its own heading,
it looked like -all- those options where sticky even though some of them
aren't. This change adds a label to the second list so it's clear they're
different.
I've renamed the check_whitespace operation to check_style. You're going to
need to change your .hg/hgrc file. While you're at it, add a pre-qrefresh
hook please.
I like the brevity of Ali's recent change, but the ambiguity of
sometimes showing the source and sometimes the target is a little
confusing. This patch makes scons typically list all sources and
all targets for each action, with the common path prefix factored
out for brevity. It's a little more verbose now but also more
informative.
Somehow Ali talked me into adding colors too, which is a whole
'nother story.
clean up the code a little bit while we're at it.
I recommend that everyone adds the pre-qrefresh hook below since it
will make qref run the style hook and not just commit/qpush
[extensions]
style = <m5 path>/util/style.py
[hooks]
pretxncommit.style = python:style.check_whitespace
pre-qrefresh.style = python:style.check_whitespace
