When v is compiled as. wasm, does it use GC or autofree memory management by default?

[Avey777]

When compiling v into a wasm executable file using the command v -b wasm -os wasi xx.v, the memory management is handled in the following ways:

1、It uses the autofree mechanism to manage memory. This means that memory is automatically freed when it is no longer needed, reducing the need for manual memory management.

2、The GC (Garbage Collection) runtime is compiled into wasm along with the code. This allows for automatic memory management and garbage collection within the wasm environment.

3、The wasm GC can be utilized using the built-in wasm GC features of runtimes such as wasmtime or wasmer. These runtimes provide additional functionality for managing memory within the wasm environment.

[JalonSolov]

@l1mey112 ☝️

[l1mey112]

Currently it uses neither. Just a simple bump allocator able to allocate at possibly at most 64KiBs without crashing. This was a basic allocator created for running the tests and all programs the wasm backend is capable of compiling.

Full code behind vlib/builtin/wasm/alloc.v:

@[has_globals]
module builtin

// Shitty `sbrk` basic `malloc` and `free` impl
// TODO: implement pure V `walloc` later

__global g_heap_base = usize(vwasm_heap_base())

// malloc dynamically allocates a `n` bytes block of memory on the heap.
// malloc returns a `byteptr` pointing to the memory address of the allocated space.
// unlike the `calloc` family of functions - malloc will not zero the memory block.
@[unsafe]
pub fn malloc(n isize) &u8 {
	if n <= 0 {
		panic('malloc(n <= 0)')
	}

	res := g_heap_base
	g_heap_base += usize(n)

	return &u8(res)
}

// free allows for manually freeing memory allocated at the address `ptr`.
// currently does not free any memory.
@[unsafe]
pub fn free(ptr voidptr) {
	_ := ptr
}