Would you pay for GC?
Ola Fosheim Grøstad
ola.fosheim.grostad at gmail.com
Tue Jan 25 11:47:26 UTC 2022
On Tuesday, 25 January 2022 at 10:56:50 UTC, Paulo Pinto wrote:
> Pity that programmer knowledge can't do much to ABI
C++ has an ABI?
So this is basically about giving a shared_ptr the semantics of a
That is not required for what we are talking about here.
> Also that trick only works in single developer code bases, good
> luck not introducing a memory corruption some months/years down
> the line.
No, this is not a big issue if you create proper ADTs. The issue
is that it is very difficult for a compiler to distinguish
between objects that "wrap ownership" around a data-structure and
nodes within a datastructure; in particular what happens to
ownership when those nodes are rearranged.
However, the programmer should have good and solid knowledge
about this, so you only need to increment on the root-object if
you know that nodes do not escape below a point in the call tree.
(And you might be able to wrap this in a reference-type specific
to the ADT).
Anyway, in C++ you tend almost always to use unique_ptr,
shared_ptr is the exception. So you usually have very few
shared_ptrs and therefore they are not all that hard to reason
For a language like D you could have ARC + borrow checker + the
ability to constrain ARC-pointers (to get a unique_ptr) for
shared objects and something GC-like for objects local to
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