Enum veriwasm::HeapStrategy

pub enum HeapStrategy {
    HeapPtrFirstArgWithGuards,
    VMCtxFirstArgWithGuards {
        vmctx_heap_base_ptr_offset: usize,
    },
}

How the Wasm heap is accessed in machine code. This will allow the check to be parameterized to work with different VMs – first Lucet, eventually Wasmtime, perhaps others – that have slightly different VM-context data structure layouts.

Variants

HeapPtrFirstArgWithGuards

The first argument to functions is a hidden argument that is the heap base. Accesses to the heap are computed relative to this base. The virtual-memory layout has sufficient guard regions that no bounds-checks are necessary as long as only an unsigned 32-bit offset is added to the base.

This corresponds to Lucet’s design.

VMCtxFirstArgWithGuards

The first argument to functions is a hidden VM-context struct pointer, and another pointer within this struct points to the Wasm heap. The guard region is assumed to be present as above. The offset to the heap-base pointer within vmctx is configurable.

This corresponds to Wasmtime’s design.

Fields of VMCtxFirstArgWithGuards

vmctx_heap_base_ptr_offset: usize

Trait Implementations

impl Clone for HeapStrategy

fn clone(&self) -> HeapStrategy

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HeapStrategy

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq<HeapStrategy> for HeapStrategy

fn eq(&self, other: &HeapStrategy) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &HeapStrategy) -> bool

This method tests for !=.

impl Copy for HeapStrategy

impl Eq for HeapStrategy

impl StructuralEq for HeapStrategy

impl StructuralPartialEq for HeapStrategy