Introduced a script to capture leaks from malloc / free

[chimicus]

This is a simple script that matches malloc and free calls. It can be expanded / adapted to track more sophisticated allocators.

[barisione]

Use a set and then you can just do .remove(alloc). This requires MemAlloc to be hashable and not modifiable so using a frozen data class as I suggested above will make it work.

[barisione]

You should remove the breakpoints you create after you are done. If you follow my suggestions from above you will have:

allocations: set[MemAlloc] = set()
try:
    alloc_bp = AllocBreakpoint()
    free_bp = FreeBreakpoint()
    [... rest of the function ...]
finally:
    alloc_bp.delete()
    free_bp.delete()

[barisione]

If you use a set then the results will be in an arbitrary order. You can do this:

for alloc in sorted(allocations, key=lambda ma: ma.bbcount):
    ...

[barisione]

There are a few possible improvements here:

• Show the bbcount as first element as it's what you are sorting on
• Show a range of addresses, not just the start
• Don't use an hex for the size
• Use commas for long bbcounts and sizes
• Pad numbers so they aligned

Maybe something like this:

print(f"{alloc.bbcount:18,}: {alloc.addr:#018x} - {alloc.addr + alloc.size:#018x} (size={alloc.size:,})")

The various bits after the : characters mean:

• 18: pad to 18 characters with spaces
• 018: pad to 18 characters with zeroes
• ,: format numbers with commas every 3 digits
• x: use hexadecimal
• #: add 0x