Integrate WithAlloc.jl

[cortner]

This integrates WithAlloc.jl as discussed in #40 .

[cortner]

My only concern right now is this block

@inline function _bumper_alloc(allocinfo::Tuple{<: Type, Vararg{Int, N}}) where {N}
   Bumper.alloc!(Bumper.default_buffer(), allocinfo...)
end

I haven't given any thought yet how to allow the use of general buffers, since I never used this myself.

[MasonProtter]

Hi @cortner, I think this got buried in my notifications and I missed it, sorry about that.

Yeah, that _bumper_alloc function will need to be modified to take the current active buffer, otherwise using the withalloc stuff would be incorrect anytime the @no_escape block uses a different buffer.

I think what's needed here would be for the @withalloc macro to be integrated into the @no_escape macro, so that the buffer used by @no_escape can be passed directly to the withalloc call, like is done on this section:

Bumper.jl/src/internals.jl

Lines 37 to 42 in 397883e

	if ex.args[1] == Symbol("@alloc")
	# replace calls to @alloc(T, size...) with alloc(T, buf, size...) where buf
	# is the current buffer in use.
	Expr(:block,
	:($tsk === $get_task() || $tsk_err()),
	Expr(:call, alloc!, b, recursive_handler.(ex.args[3:end])...))

Basically, Bumper.@alloc isn't a real macro, it's actually just a stub, and the @no_escape macro is the one that looks for uses of @alloc, and transforms that into alloc calls on a buffer.

[cortner]

thanks for the explanation. I'll try and get back to this over the next few days, but it might take longer.

[cortner]

Apologies for the delay, I will try to get back to it, but it takes some time for me to understand the internals well enough to rewrite this correctly.