llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-13 04:30:23 +00:00

History

Chandler Carruth 73c35d86b9 Add time getters to the process interface for requesting the elapsed wall time, user time, and system time since a process started. For walltime, we currently use TimeValue's interface and a global initializer to compute a close approximation of total process runtime. For user time, this adds support for an somewhat more precise timing mechanism -- clock_gettime with the CLOCK_PROCESS_CPUTIME_ID clock selected. For system time, we have to do a full getrusage call to extract the system time from the OS. This is expensive but unavoidable. In passing, clean up the implementation of the old APIs and fix some latent bugs in the Windows code. This might have manifested on Windows ARM systems or other systems with strange 64-bit integer behavior. The old API for this both user time and system time simultaneously from a single getrusage call. While this results in fewer system calls, it also results in a lower precision user time and if only user time is desired, it introduces a higher overhead. It may be worthwhile to switch some of the pass timers to not track system time and directly track user and wall time. The old API also tracked walltime in a confusing way -- it just set it to the current walltime rather than providing any measure of wall time since the process started the way buth user and system time are tracked. The new API is more consistent here. The plan is to eventually implement these methods for a child process by using the wait3(2) system call to populate an rusage struct representing the whole subprocess execution. That way, after waiting on a child process its stats will become accurate and cheap to query. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171551 91177308-0d34-0410-b5e6-96231b3b80d8		2013-01-04 23:19:55 +00:00
..
m4	Revert 'Fix a typo 'iff' => 'if''. iff is an abreviation of if and only if. See: http://en.wikipedia.org/wiki/If_and_only_if Commit 164767	2012-09-27 10:14:43 +00:00
AutoRegen.sh	AutoRegen.sh: update reference to documentation	2012-12-24 15:01:59 +00:00
config.guess	Add support for the OpenBSD for Bitrig.	2012-08-06 20:52:18 +00:00
config.sub	Hexagon backend support	2011-12-12 21:14:40 +00:00
configure.ac	Add time getters to the process interface for requesting the elapsed	2013-01-04 23:19:55 +00:00
depcomp
ExportMap.map
install-sh
LICENSE.TXT
ltmain.sh	Add support for the OpenBSD for Bitrig.	2012-08-06 20:52:18 +00:00
missing
mkinstalldirs
README.TXT

README.TXT

Upgrading Libtool
===============================================================================

If you are in the mood to upgrade libtool, you must do the following:

 1. Get the new version of libtool and put it in <SRC>
 2. configure/build/install libtool with --prefix=<PFX>
 3. Copy <SRC>/ltdl.m4 to llvm/autoconf/m4
 4. Copy <PFX>/share/aclocal/libtool.m4 to llvm/autoconf/m4/libtool.m4
 5. Copy <PFX>/share/libtool/ltmain.sh to llvm/autoconf/ltmain.sh
 6. Copy <PFX>/share/libtool/libltdl/ltdl.c to llvm/lib/System
 7. Copy <PFX>/share/libtool/libltdl/ltdl.h to llvm/lib/System
 8. Edit the ltdl.h file to #include "llvm/Config/config.h" at the very top. You
    might also need to resolve some compiler warnings (typically about
    comparison of signed vs. unsigned values). But, you won't find out about 
    those until you build LLVM (step 13).
 9. Edit the llvm/autoconf/m4/libtool.m4 file so that:
    a) in AC_PROB_LIBTOOL macro, the value of LIBTOOL is set to
       $(top_builddir)/mklib, not $(top_builddir)/libtool
    b) in AC_LIBTOOL_SETUP macro, the variable default_ofile is set to 
       "mklib" instead of "libtool"
    c) s/AC_ENABLE_SHARED_DEFAULT/enable_shared_default/g
    d) s/AC_ENABLE_STATIC_DEFAULT/enable_static_default/g
    e) s/AC_ENABLE_FAST_INSTALL_DEFAULT/enable_fast_install_default/g
10. Run "autoupdate libtool.m4 ltdl.m4" in the llvm/autoconf/m4 directory.
    This should correctly update the macro definitions in the libtool m4 
    files to match the version of autoconf that LLVM uses. This converts
    AC_HELP_STRING to AS_HELP_STRING and AC_TRY_LINK to AC_LINK_IFELSE, amongst
    other things. You may need to manually adjust the files.
11. Run AutoRegen.sh to get the new macros into configure script
12. If there are any warnings from AutoRegen.sh, go to step 9.
13. Rebuild LLVM, making sure it reconfigures
14. Test the JIT which uses libltdl
15. If it all works, only THEN commit the changes.

Upgrading autoconf
===============================================================================

If you are in the mood to upgrade autoconf, you should:

 1. Consider not upgrading.
 2. No really, this is a hassle, you don't want to do it.
 3. Get the new version of autoconf and put it in <SRC>
 4. configure/build/install autoconf with --prefix=<PFX>
 5. Run autoupdate on all the m4 macros in llvm/autoconf/m4
 6. Run autoupdate on llvm/autoconf/configure.ac
 7. Regenerate configure script with AutoRegen.sh
 8. If there are any warnings from AutoRegen.sh, fix them and go to step 7.
 9. Test, test, test.