Commit Graph

737 Commits

Author SHA1 Message Date
Patrik Hagglund
d4bf7a3853 Remove error output from configure if CFLAGS is set (r174313).
This fixes PR16724.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191289 91177308-0d34-0410-b5e6-96231b3b80d8
2013-09-24 11:38:45 +00:00
Patrik Hagglund
6f74b140c4 Fix for executing AutoRegen.sh. Revert a part of r187209.
Since r187209, which modified ltdl.m4, I was unable to execute
AutoRegen.sh, getting:

  ../configure:10779: error: possibly undefined macro: AC_LTDL_FUNC_ARGZ

This commit re-adds AC_LTDL_FUNC_ARGZ to ltdl.m4, as a quick fix. For me, this
corresponds to the configure file currently checked in.

(However, the ltdl library seems to be unused since r74924 in 2009,
except for the use of the LTDL_SHLIB_EXT macro in
bugpoint(?). Therefore, the right solution seems to try to get rid of
the local ltdl.m4 file, specified by autoconf/README.TXT.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190677 91177308-0d34-0410-b5e6-96231b3b80d8
2013-09-13 10:29:42 +00:00
Daniel Dunbar
e179b31bfc [conf] Add config variable to disable crash related overrides.
- We do some nasty things w.r.t. installing or overriding signal handlers in
   order to improve our crash recovery support or interaction with crash
   reporting software, and those things are not necessarily appropriate when
   LLVM is being linked into a client application that has its own ideas about
   how to do things. This gives those clients a way to disable that handling at
   build time.

 - Currently, the code this guards is all Apple specific, but other platforms
   might have the same concerns so I went for a more generic configure
   name. Someone who is more familiar with library embedding on Windows can
   handle choosing which of the Windows/Signals.inc behaviors might make sense
   to go under this flag.

 - This also fixes the proper autoconf'ing of ENABLE_BACKTRACES. The code
   expects it to be undefined when disabled, but the autoconf check was just
   defining it to 0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189694 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-30 20:39:21 +00:00
Jordan Rose
3e7f1a9901 Autoconf: The Clang ARC migrator now depends on the static analyzer.
I don't actually have a version of autoconf so I edited configure directly
as well. It's copy-pasted so I think there was little margin for error.

See also Clang-side dependency graph changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189026 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-22 15:49:53 +00:00
Joerg Sonnenberger
a915b410df Recognize NetBSD's terminfo implementation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188606 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-17 11:06:00 +00:00
Chandler Carruth
3729d7d62b Remove all checking for the various terminfo headers (term.h and
curses.h). Finding these headers is next to impossible. For example, on
Debian systems libtinfo-dev provides the terminfo reading library we
want, but *not* term.h. For the header, you have to use libncurses-dev.
And libncursesw-dev provides a *different* term.h in a different
location!

These headers aren't worth it. We want two functions the signatures of
which are clearly spec'ed in sys-v and other documentation. Just declare
them ourselves and call them. This should fix some debian builders and
provide better support for "minimal" debian systems that do want color
autodetection.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188165 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-12 10:40:11 +00:00
Chandler Carruth
8d8bdff6d7 Target a minimal terminfo library rather than necessarily a full curses
library for color support detection. This still will use a curses
library if that is all we have available on the system. This change
tries to use a smaller subset of the curses library, specifically the
subset that is on some systems split off into a separate library. For
example, if you install ncurses configured --with-tinfo, a 'libtinfo' is
install that provides just the terminfo querying functionality. That
library is now used instead of curses when it is available.

This happens to fix a build error on systems with that library because
when we tried to link ncurses into the binary, we didn't pull tinfo in
as well. =]

It should also provide an easy path for supporting the NetBSD
libterminfo library, but as I don't have access to a NetBSD system I'm
leaving adding that support to those folks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188160 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-12 09:49:17 +00:00
Chandler Carruth
f7364d5833 Add support for linking against a curses library when available and
using it to detect whether or not a terminal supports colors. This
replaces a particularly egregious hack that merely compared the TERM
environment variable to "dumb". That doesn't really translate to
a reasonable experience for users that have actually ensured their
terminal's capabilities are accurately reflected.

This makes testing a terminal for color support somewhat more expensive,
but it is called very rarely anyways. The important fast path when the
output is being piped somewhere is already in place.

The global lock may seem excessive, but the spec for calling into curses
is *terrible*. The whole library is terrible, and I spent quite a bit of
time looking for a better way of doing this before convincing myself
that this was the fundamentally correct way to behave. The damage of the
curses library is very narrowly confined, and we continue to use raw
escape codes for actually manipulating the colors which is a much sane
system than directly using curses here (IMO).

If this causes trouble for folks, please let me know. I've tested it on
Linux and will watch the bots carefully. I've also worked to account for
the variances of curses interfaces that I could finde documentation for,
but that may not have been sufficient.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187874 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-07 08:47:36 +00:00
Bob Wilson
244acf3a4b Link with -rdynamic instead of -Wl,-export-dynamic.
Recent versions of the OS X linker support this but follow the existing
OS X linker convention of using an underscore in the option name, i.e.,
-export_dynamic. Rather than changing our configure scripts to check for
that alternate spelling, it is simpler to just use the compiler's -rdynamic
option and let it deal with translating that to the appropriate linker
option. One potential disadvantage of this approach is that the compiler
will typically ignore -rdynamic on platforms where it is not supported, so
the HAVE_LINK_EXPORT_DYNAMIC in config.h will not necessarily show whether
that option has any effect or not. I don't see any in-tree uses of that
macro, so I'm assuming it is OK.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187686 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-02 22:51:06 +00:00
Reid Kleckner
65985348c5 Remove dead or useless header checks from cmake and autoconf
On Windows, this improves clean cmake configuration time on my
workstation from 1m58s to 1m32s, which is pretty significant.  There's
probably more that can be done here, but this is the low hanging fruit.

Eric volunteered to regenerate ./configure for me.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187209 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-26 16:54:23 +00:00
Bill Schmidt
f38cc38fa6 [PowerPC] Support powerpc64le as a syntax-checking target.
This patch provides basic support for powerpc64le as an LLVM target.
However, use of this target will not actually generate little-endian
code.  Instead, use of the target will cause the correct little-endian
built-in defines to be generated, so that code that tests for
__LITTLE_ENDIAN__, for example, will be correctly parsed for
syntax-only testing.  Code generation will otherwise be the same as
powerpc64 (big-endian), for now.

The patch leaves open the possibility of creating a little-endian
PowerPC64 back end, but there is no immediate intent to create such a
thing.

The LLVM portions of this patch simply add ppc64le coverage everywhere
that ppc64 coverage currently exists.  There is nothing of any import
worth testing until such time as little-endian code generation is
implemented.  In the corresponding Clang patch, there is a new test
case variant to ensure that correct built-in defines for little-endian
code are generated.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187179 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-26 01:35:43 +00:00
Rafael Espindola
6fccaafd8b Remove the mblaze backend from llvm.
Approval in here http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-July/064169.html

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187145 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-25 18:55:05 +00:00
Eric Christopher
69097a29ce No ',' between programs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185867 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-08 21:18:54 +00:00
Matt Arsenault
e1e7310749 Find xdot or xdot.py.
Ubuntu installs this as xdot, so finding xdot.py would fail.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185860 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-08 20:24:54 +00:00
Eric Christopher
c589a5f284 Reapply r185601 with a fix for the cmake build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185605 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-04 01:10:38 +00:00
Eric Christopher
2333a31df5 Temporarily revert 185601 as it caused cmake build regressions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185603 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-04 00:51:26 +00:00
Eric Christopher
d1280c194b Add support for futimens for platforms that don't support futimes.
Patch by pashev.igor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185601 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-04 00:47:09 +00:00
Sylvestre Ledru
ba62f2f1bf The build system is currently miss-identifying GNU/kFreeBSD as FreeBSD.
This kind of simplification is sometimes useful, but in general it's not correct. 

As GNU/kFreeBSD is an hybrid system, for kernel-related issues we want to match the
build definitions used for FreeBSD, whereas for userland-related issues we want to
match the definitions used for other systems with Glibc.

The current modification adjusts the build system so that they can be distinguished,
and explicitly adds GNU/kFreeBSD to the build checks in which it belongs.

Fixes bug #16444.

Patch by Robert Millan in the context of Debian.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185311 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-01 08:07:52 +00:00
Eric Christopher
1baa38147a Add an autoconf option for turning on -gsplit-dwarf by default
when building llvm. This saves quite a bit of time and space when
linking. Please report any problems via bugzilla.

Caveats:

a) This will only work on linux
b) This requires a fairly new binutils
c) This requires a fairly new gdb

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184808 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-25 01:12:25 +00:00
Rafael Espindola
ba30d60ebb Don't define LTDL_SHLIBPATH_VAR.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183771 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-11 19:04:13 +00:00
Rafael Espindola
add4c2fbb1 Don't define LLVM_LIBDIR, it is not used anymore.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183769 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-11 18:52:11 +00:00
Rafael Espindola
059d360266 Make R600 non-experimental.
The r600 backend has been in tree for some time now. Marking it as
non-experimental to avoid accidental breakage.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182442 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-22 00:35:47 +00:00
Bill Wendling
0c25b8f07e We're in 3.4 land now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181350 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-07 20:31:28 +00:00
Ulrich Weigand
9887cbed05 [SystemZ] Add to --enable-targets=all
This patch finally enables the SystemZ target in the default build
(with --enable-targets=all).

Patch by Richard Sandiford.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181209 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-06 16:23:07 +00:00
Ulrich Weigand
735ab83b3c [SystemZ] Add configure bits
This patch wires up the SystemZ target in configure, so that it can now be
built using --enable-targets=systemz.   It is not yet included in the default
build (--enable-targets=all); this will be done by a follow-up patch.

Patch by Richard Sandiford.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181208 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-06 16:22:34 +00:00
Tim Northover
d66ad6c571 Allow host triple to be correctly overridden in CMake builds
The intended semantics mirror autoconf, where the user is able to
specify a host triple, but if it's left to the build system then
"config.guess" is invoked for the default.

This also renames the LLVM_HOSTTRIPLE define to LLVM_HOST_TRIPLE to
fit in with the style of the surrounding defines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181112 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-04 07:36:23 +00:00
Benjamin Kramer
5212b4eb71 Autoconf: Compile cxxabi.h in C++ mode.
Should fix PR15877.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181026 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-03 15:55:06 +00:00
Joerg Sonnenberger
dfa0e92fa0 Only use cxxabi.h's demangler, if it is actually available.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180684 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-27 22:12:32 +00:00
Alexey Samsonov
ee03c949b8 Add basic zlib support to LLVM. This would allow to use compression/uncompression in selected LLVM tools.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180083 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-23 08:28:39 +00:00
Jia Liu
a626be362b Add AArch64 into $llvm_cv_target_arch in configure, reviewed by Tim Northover & Eric Christopher
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180025 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-22 16:26:15 +00:00
Joerg Sonnenberger
f9a7132df8 Refine fenv.h handling: check if the desired macros exist, before using
it. NetBSD/ARM and TILE-Gx are examples for platforms that have an
unusable fenv.h and this avoids the need for a blacklist.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177865 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-25 13:13:33 +00:00
Eric Christopher
c6aa834836 Turn anonymous type in anonymous union warning back on after cleaning up
issues.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177136 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-15 00:43:00 +00:00
Dmitri Gribenko
7c62701c22 configure: remove workaround for gcc's -Wno-maybe-uninitialized
Since r174770 gcc version check is not needed because CXX_FLAG_CHECK
implements the workaround itself.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175080 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-13 21:19:39 +00:00
Richard Smith
d31bd24b40 configure: when performing a compiler feature test for a -Wno-foo flag, attempt
to use -Wfoo instead of -Wno-foo. This works around a bug in some versions of
gcc, where it will silently accept an unknown -Wno-foo option, but will
generate an error for a compile which uses -Wno-foo if that compile also
triggers any warnings.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174770 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-08 22:55:10 +00:00
Owen Anderson
ec643abe69 Conditionalize constant folding of math intrinsics on the availability of an implementation on the host. This is a little bit unfortunate, but until someone decides to implement a full libm for APFloat, we don't have a better way to get this functionality.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174561 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-07 00:21:34 +00:00
Tim Northover
4c40840d38 Enable AArch64 as a target built by default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174322 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-04 12:32:21 +00:00
Patrik Hagglund
6c440fcea5 Pass CPPFLAGS/CFLAGS/CXXFLAGS from the environment of configure to
Makefile.config.

This is implied at the bottom of the help text of configure (besides
CC/CXX/LDFLAGS, already passed to Makefile.config).

For backward compatibility, the values of CFLAGS and CXXFLAGS defaults
to empty, overriding the default values provided by autoconf (for
example, '-g -O2' when CC=gcc').

$(CPP) is not used by our makefiles. Therefore, the value of CPP is
not passed to Makefile.config, despite beeing mentioned by 'configure
--help'.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174313 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-04 08:15:53 +00:00
Joerg Sonnenberger
f841064592 Recognize aarch64 for --enable-targets as advertised.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174288 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-03 17:06:49 +00:00
Richard Smith
1983f54dae Add -Wno-nested-anon-types to -pedantic builds of LLVM. This Clang warning
catches uses of an extremely minor and widely-available C++ extension (which
every C++ compiler I could find supports, but EDG and Clang reject in strict
mode).

The diagnosed code pattern looks like this:

struct X {
  union {
    struct {
      int a;
      int b;
    } S;
  };
};


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174103 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-31 22:19:12 +00:00
Tim Northover
72062f5744 Add AArch64 as an experimental target.
This patch adds support for AArch64 (ARM's 64-bit architecture) to
LLVM in the "experimental" category. Currently, it won't be built
unless requested explicitly.

This initial commit should have support for:
    + Assembly of all scalar (i.e. non-NEON, non-Crypto) instructions
      (except the late addition CRC instructions).
    + CodeGen features required for C++03 and C99.
    + Compilation for the "small" memory model: code+static data <
      4GB.
    + Absolute and position-independent code.
    + GNU-style (i.e. "__thread") TLS.
    + Debugging information.

The principal omission, currently, is performance tuning.

This patch excludes the NEON support also reviewed due to an outbreak of
batshit insanity in our legal department. That will be committed soon bringing
the changes to precisely what has been approved.

Further reviews would be gratefully received.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174054 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-31 12:12:40 +00:00
Saleem Abdulrasool
3ef8b0adb4 build: add --with-python option
This adds a new --with-python option to allow configuration of the python binary
for building.  If not specified, $PATH will be searched for common python binary
names (python, python2, python3).  If specified, and the path is not executable,
it will attempt to search $PATH.

Signed-off-by: Saleem Abdulrasool <compnerd@compnerd.org>
Reviewed-by: Eric Christopher <echristo@gmail.com>, Daniel Dunbar <daniel@zuster.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173890 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-30 04:07:37 +00:00
NAKAMURA Takumi
d749382c8c [autoconf]: Fix description in HAVE_CRASHREPORTER_INFO.
http://llvm-reviews.chandlerc.com/D332

Signed-off-by: Saleem Abdulrasool <compnerd@compnerd.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173879 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-30 01:38:03 +00:00
NAKAMURA Takumi
a4afeef186 [autoconf] Fix m4 quoting for newer autotools
This simply fixes up quoting of macro invocations to appease newer versions of autotools.

http://llvm-reviews.chandlerc.com/D332

Signed-off-by: Saleem Abdulrasool <compnerd@compnerd.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173878 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-30 01:37:55 +00:00
NAKAMURA Takumi
fd6fbec86d [autoconf] Fix 80+ and quoting.
Additional quoting for safety and satisfying newer autotools.  Fix a couple of 80 column violations.

http://llvm-reviews.chandlerc.com/D333

Signed-off-by: Saleem Abdulrasool <compnerd@compnerd.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173877 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-30 01:37:49 +00:00
David Greene
0b198ca38f Disable Uninitialized Use Warnings for Broken gcc Versions
Some versions of gcc accept unsupported -W flags and run just fine if
there are no warnings, but die with an unsupported flag error if a
warning is encountered.  gcc 4.3 and gcc 4.4 both exhibit this
behavior for -Wno-maybe-uninitialized.  Therefore, if the flag check
for -Wno-maybe-uninitialized succeeds, only use
-Wno-maybe-uninitialized if we are using gcc version 4.7 or greater.
Use -Wno-uninitialized otherwise.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172543 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-15 18:21:15 +00:00
David Greene
d2f8216ba4 Disable -Wuninitialized for gcc
If the compiler is gcc, disable variants of -Wuninitialized depending
on the gcc version.  This gets a lot of false positive warnings out of
the build.

Generate a new configure for the gcc -Wno-uninitialized fix.

Pick up -Wno-uninitialized from configure

Add the option -Wno[-maybe]-uninitialized as determined by configure.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172006 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-09 22:11:13 +00:00
Dmitri Gribenko
a7303360ae Configure: if we compile with clang, check that it is not broken
Some linux distibutions (for example, Mageia 2, Fedora 17) ship Clang that is
essentially broken for the end user.  Clang can not find or compile libstdc++
headers.

The issue is that our configure prefers clang over gcc, thus selecting a broken
Clang when a working GCC is available.

Now we detect this issue by compiling a simple program.  If it does not
compile, configure stops with an error suggesting the user to select a
different compiler.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171975 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-09 15:25:30 +00:00
Chandler Carruth
1751a73f19 Fix a stray 'dnl' that my editor line-wrapped into this comment. Thanks
to filcab on IRC for spotting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171573 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-05 00:34:40 +00:00
Chandler Carruth
234aaf08c8 Finally, fix the autoconf setup to allow for a missing clock_gettime;
the source code should now be set up to handle this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171570 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-05 00:29:06 +00:00
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