Raising exceptions halfway through a memory allocation is undefined
behavior since exceptions themselves require multiple allocations and
the allocator functions are not reentrant.
It is of course also expensive performance-wise to introduce lots of
exception-raising code everywhere since it breaks many optimisations and
bloats the code.
Finally, performing pointer arithmetic with signed integers is incorrect
for example on on a 32-bit systems that allows up to 3gb of address
space for applications (large address extensions) and unnecessary
elsewhere - broadly, stuff inside the memory allocator is generated by
the compiler or controlled by the standard library meaning that
applications should not be forced to pay this price.
If we wanted to check for overflow, the right way would be in the
initial allocation location where both the size and count of objects is
known.
The code is updated to use the same arithmetic operator style as for
refc with unchecked operations rather than disabling overflow checking
wholesale in the allocator module - there are reasons for both, but
going with the existing flow seems like an easier place to start.
* Refactor and optimize cellseqs_v2 in Nim standard library
* Extract resizing logic into a separate 'resize' procedure for better readability and separation of concerns
* Implement realloc for non-threaded cases to improve memory operations efficiency
* Use ',' instead of ';' between parameters in 'add' procedure for consistency with other Nim code
* Respond to Araq's feedback: Refactor resize function to use reallocShared
This commit replaces the usage of allocShared and deallocShared with reallocShared to optimize memory allocation and deallocation while resizing the CellSeq.
* ORC refactoring in preparation for further changes (=dispose must die)
* ORC: embrace =destroy, avoid =dispose
* ORC: no need for =dispose
* closes#18421
* cycle collector: new implementation
* cycle collector: make self-adaptive based on its previous effectiveness
* cycle collector: added Lins's jump stack to improve traversal from 3*N to 2*N
* cycle collector: make tests green
* API extensions and bugfixes
* code cleanup and use --gc:orc for tasyncawait
