LLVM profdata format support library

This library provides support for the llvm-profdata file format in a program compiled using Clang‘s SourceBasedCoverage or LLVM profiling instrumentation. This is a substitute for the standard runtime included in the compiler-rt suite. It’s meant for low-level environments like kernels and boot loaders where toolchain-supplied runtime libraries are not available. It does not implement any I/O or data transport itself, but only a simple API for getting a dump in llvm-profdata format into a memory buffer and for interacting with the code instrumentation generated by the compiler.