Comment by jstimpfle
8 days ago
I've argued elsewhere some things that are wrong with RAII and C++ objects in general.
Here I would just like to mention that if you have to rely on "de-virtualization" passes, you're in a miserable situation architecturally. If you have code where the overhead of virtual function calls might be too much to pay, don't do virtual functions then. End of story.
To deconstruct a pool of objects, I don't see what should ever be wrong with a function pointer. The overhead of loading the function pointer will get divided by the number of objects being deconstructed. Care to explain what's the issue here?
> I don't see what should ever be wrong with a function pointer. [...]Care to explain what's the issue here?
1. You're writing code you don't have to
2. That adds runtime overhead
3. That when you screw up has non-trivial security & resource management side effects
This is objectively indefeasible in nearly any vaguely professional context.
1. No, you're not writing code you don't have to. It's not different to implementing this as non-virtual methods, in fact I'd argue doing simple functions is more straightforward.
2. And the code being compiled is abstract & generic, it won't be instantiated for every type and bloat the executable or instruction cache.
3. Security concerns: With C++ virtual methods every object carries a mutable pointer too (to a vtable containing function pointers). What resource management side effects please?
Re #3: vtable pointers aren't mutable...?
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I've argued elsewhere some things that are wrong with RAII and C++ objects in general.
You claimed there were problems many times for sure, I don't think you came up with any evidence of those problems.
You keep "asking" for evidence but the only evidence presented by yourself is that you have merely surface-level understanding of the subject matter, and are looking for arguments, not insight and critical examination.
It's your claim that destructors are harmful so the burden of proof is on you.
People use them because by default values have scope based lifetimes and destructors unify the handling of stack based values which require no explicit cleanup with data structures that heap allocate, which require no explicit cleanup once the destructor is implemented.
This is the opposite of C where even though the resource cleanup needs to happen on scope end, it is not automatic, and so becomes a source of bugs. This is exaggerated when there are multiple returns, gotos, macros and other sources of branching especially for error handling.
This automation also removes boilerplate so there is less management that needs to be done when using data structures.
What was your evidence or explanation?
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