LLVM already has a feature to profile the JIT-compiled code with VTune. This is done using Intel JIT Profiling API (https://github.com/intel/ittapi). Function information is captured by VTune as soon as the function is JIT-compiled. We tried to use the same approach to report the function information generated by the MCJIT engine – read parsing the debug information for in-memory ELF module and report it using JIT API. As the results, we figured out that it did not work properly for the following cases: inline functions, the functions located in multiple source files, the functions having several bodies (address ranges).
To overcome limitations described above, we have introduced new APIs as a part of Intel ITT APIs to report the entire in-memory ELF module to be further processed as regular ELF binaries with debug information.
- Switches LLVM to open source version of Intel ITT/JIT APIs ((https://github.com/intel/ittapi) to keep it always up to date
- Adds support of profiling the code generated by MCJIT engine using Intel VTune profiler
Another separate patch will get rid of obsolete Intel ITT APIs stuff, having LLVM already switched to https://github.com/intel/ittapi
ittnotify_config.h ittnotify_types.h jitprofiling.c jitprofiling.h