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
..
ADT	Add an iplist::clearAndLeakNodesUnsafely() function.	2013-01-04 22:35:42 +00:00
Analysis	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
Bitcode	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
ExecutionEngine	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
Option	Sort a few more #include lines in tools/... unittests/... and utils/...	2013-01-02 10:26:28 +00:00
Support	Add time getters to the process interface for requesting the elapsed	2013-01-04 23:19:55 +00:00
Transforms	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
VMCore	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
CMakeLists.txt	Copy clang/Driver/<Option parsing stuff> to llvm.	2012-12-05 00:29:32 +00:00
Makefile	Undo the hack in r147427 and move this unittest to a better home. This	2012-01-02 09:19:48 +00:00
Makefile.unittest	build/unittests: Fix llvm-config names for gtest libraries, and bring Makefile	2011-12-15 23:35:08 +00:00