Boehm-Demers-Weiser conservative C/C++ Garbage Collector

Re:Boehm-Demers-Weiser conservative C/C++ Garbage Collector by zozbot234 on Sunday January 21, 2024 @12:58PM (#39080806)

The compiler support you need in practice is quite limited. There is an implementation of incremental cycle collection in Rust: https://github.com/chc4/samsara It's made possible because Rust can tell apart read-only and read-write references (except for references to interior mutable objects, but these are known to the compiler and references to them can be treated as read-write). This avoids a global stop-the-world for the entire program.

Cascading deletes are rare in practice, and if anything they are inherent to deterministic deletion, which is often a desirable property. When they're possible, one can often use arena allocation to avoid the issue altogether since arenas are managed as a single allocation.

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Re:Boehm-Demers-Weiser conservative C/C++ Garbage Collector by rbehrends on Sunday January 21, 2024 @01:16PM (#39081015)

> The compiler support you need in practice is quite limited.

This is true, but it's absent especially in C. Of course, as long as you can intercept writes and/or reads through pointers, you are good to go in principle. However, that solution may not be efficient.

> Cascading deletes are rare in practice

An array of objects (e.g. std::vector<std::string>) already has unbounded deallocation cost. People mostly think of tree-like structures here, but such structures only add the risk of stack blowout to the lack of an upper bound. But in principle, any container that does not have a size limit can give rise to unbounded pause times.

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