A versatile shadow memory library based on the paper How to shadow every byte of memory used by a program by Nicholas Nethercote and Julian Seward (2007).
Shadow memory can be thought of as a big associative array indexed by memory addresses. It allows to store additional "shadow" data characterizing, but not interfering with, the original data at any given address.
For instance, Valgrind-Memcheck uses a shadow memory tool to track addressability and validity bits in order to detect memory errors. The flexible-shadow tool has been developed for the automatic differentiation tool Derivgrind, which needs to keep track of dot values or variable indices.
See test.cpp.
- Users can configure the number of shadow map layers and how many address bits each of them resolves.
- Users can configure the functions used to allocate, deallocate, and copy memory. For instance, the alternative standard library interface defined in flexible-shadow-valgrindstdlib.hpp allows to use flexible-shadow in a Valgrind tool.