GTY markers added to `range_storage` classes for garbage collection.
GTY markers have been added to `vrange_storage` classes in GCC to prepare for future pointer analysis and garbage collection within value range data structures.
GCC’s internal vrange_storage classes, which are critical for storing value range information used in various optimizations, have been updated with GTY markers. This change is a preparatory step for future enhancements, specifically the introduction of a points-to tree within prange analysis. The GTY markers enable the compiler’s garbage collection system to correctly track and manage memory for these data structures, ensuring memory safety and paving the way for more sophisticated pointer analysis capabilities.
In Details
This commit adds GTY markers to the vrange_storage, irange_storage, prange_storage, and frange_storage classes within value-range-storage.h and explicitly initializes vrange_storage members in corresponding constructors in value-range-storage.cc. This is a foundational change, intended to enable the garbage collector (GTY) to correctly traverse and manage memory for these value range data structures. The primary motivation is to facilitate the future integration of a points-to analysis tree into prange, which will require robust memory management for inter-procedural pointer t…
For Context
Compilers often perform sophisticated analyses to understand how values change throughout a program, a process known as 'value range analysis.' This helps in optimizations like eliminating unnecessary checks or simplifying calculations. For these analyses, the compiler uses internal data structures to store information about the 'ranges' of possible values a variable might hold. This change involves adding special 'GTY markers' to these internal data structures within GCC. Think of GTY markers as little labels that tell the compiler's internal memory management system (like a garbage collector) which parts of these data structures contain pointers to other memory locations. This is a preparatory step for a future enhancement that will allow GCC to do more advanced analysis of how pointers (variables that store memory addresses) interact with these value ranges, ultimately leading to more powerful optimizations and a more robust compiler.