This patch adds a new set of substitutions to the lit run lines for order files and PGO generation which run the clang driver to get the cc1 command, then execute the cc1 command directly. This allows the scripts to bypass profiling the clang driver over and over again.
The approach in this patch was discussed via IRC with Sean Silvas.
Special thanks to Daniel Dunbar whose out-of-tree code I liberally plagiarized.
llvm-svn: 263997
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