deletions | additions       diff --git a/osr-llvm.tex b/osr-llvm.tex  index 1dd6fe4..f6ee7e2 100644  --- a/osr-llvm.tex  +++ b/osr-llvm.tex 
...
In this section we discuss our implementation of the approach described in \mysection\ref{se:overview} in \tinyvm, a proof-of-concept virtual machine we developed as a playground to exercise our OSR techniques. TinyVM is based on LLVM's MCJIT compiler and supports interactive invocation of LLVM IR functions either generated at run-time or loaded from disk. The main design goal behind TinyVM is the creation of an interactive environment for IR manipulation and JIT-compilation of functions: for instance, it allows the user to insert OSR points in loaded functions, run optimization passes on them or display their CFGs, repeatedly invoke a function for a specified amount of times and so on. TinyVM supports dynamic library loading and linking, and comes with a helper component for MCJIT that simplifies tasks such as handling multiple IR modules, symbol resolution in presence of multiple versions of a function, and tracking native code and other machine-level generated object such as Stackmaps.  To explain how OSR can be encoded in IR using \tinyvm, we consider the toy example of \myfigure\ref{fi:isord-example}. Function {\tt isord} checks whether an array of numbers is sorted according to some ordering given by a comparator. The scenario we explore is profile-driven optimization, where we dynamically divert control to a faster version if the number of iterations exceeds a certain threshold. To achieve this goal, we use deferred compilation by instrumenting {\tt isord} in \tinyvm\ with an open OSR at the beginning of the loop body, as shown in \myfigure\ref{fig:isordfrom}. The figure shows how the original {\tt isord} code is instrumented by \tinyvm, highlighting in grey the added portions. A new basic block is placed at the beginning of the loob body, incrementing the hotness counter {\tt p.osr} and testing if it reached the threshold (1000 iterations in this example). Notice that maintaining the SSA form requires adjusting phi nodes.  %To place an open OSR, \tinyvm\ requires the following pieces of information: 1) a pointer to the