Summary:
This patch extends the lit-based perf-training tooling supplied for PGO data generation to also generate linker order files using dtrace.
This patch should work on any system that has dtrace. If CMake can find the dtrace tool it will generate a target 'generate-order-file' which will run the per-training tests wrapped by dtrace to capture function entries. There are several algorithms implemented for sorting the order files which can be experimented with for best performance. The dtrace wrapper also supports bot oneshot and pid probes.
The perf-helper.py changes to support order file construction are ported from internal changes by ddunbar; he gets all the credit for the hard work here, I just copy and pasted.
Note: I've tested these patches on FreeBSD and OS X 10.10.
Reviewers: ddunbar, bogner, silvas
Subscribers: llvm-commits, emaste
Differential Revision: http://reviews.llvm.org/D16134
llvm-svn: 257934
Summary:
This patch adds support for using LIT to drive generating PGO profile data for clang.
This first pass implementation should work on Linux and Unix based platforms. If you build clang using CMake with LLVM_BUILD_INSTRUMENTED=On the CMake build generates a generate-profdata target that will use the just-built clang to build any test files (see hello_world.cpp as an example). Each test compile will generate profraw files for each clang process. After all tests have run CMake will merge the profraw files using llvm-profdata.
Future opportunities for extension:
* Support for Build->Profile->Build bootstrapping
* Support for linker order file generation using a similar mechanism and the same training data
* Support for Windows
Reviewers: dexonsmith, friss, bogner, cmatthews, vsk, silvas
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D15462
llvm-svn: 255740
Chris Bieneman