Struct WasmMemory 

pub struct WasmMemory {
    pub index: u32,
    pub initial_pages: u32,
    pub max_pages: Option<u32>,
    pub shared: bool,
    pub memory64: bool,
    pub page_size_log2: Option<u32>,
}

WASM linear memory specification

Fields

index: u32

Memory index

initial_pages: u32

Initial size in pages (64KB each)

max_pages: Option<u32>

Maximum size in pages (if specified)

shared: bool

Whether memory is shared (requires threads proposal)

memory64: bool

#1209: whether this memory is 64-bit-INDEXED (the memory64 proposal, (memory i64 ...)) rather than the default 32-bit index type. No codegen path in this crate handles an i64 memory index — data-segment offsets are decoded i32.const-only (silently DROPPING an i64.const-offset segment) and every address-materialization path assumes a 32-bit address, so a memory64 module compiled today produces EXECUTABLE, WRONG code rather than failing to compile. This flag is consumed by refuse_memory64_module in synth-cli to turn that into a loud decline at decode time, the #1046 pattern.

page_size_log2: Option<u32>

#1315: the log2 of this memory’s DECLARED page size (the custom-page-sizes proposal, (memory 1 1 (pagesize N))), or None for the default 64 KiB page. wasmparser decodes it; nothing in this workspace read it, so a memory declared one byte long was reported and reserved as 65536 — and __synth_mem_size_N, which the embedder programs one MPU region from (#1145), inherited the over-grant by the page-size ratio. Consumed by refuse_custom_page_size in synth-cli, the refuse_memory64_module (#1209) pattern: decode the declaration, then decline loudly rather than silently ignore it.

Implementations

impl WasmMemory

pub fn page_bytes(&self) -> u32

#1441: this memory’s DECLARED page size in bytes.

The custom-page-sizes proposal permits EXACTLY two values — the vendored custom-page-sizes-invalid.wast asserts (pagesize 32) invalid BY NAME under its own “Power-of-two page sizes that are not 1 or 64KiB” heading — so on any module that validates page_size_log2 is 0 or 16.

checked_shl rather than <<, and this is deliberate rather than defensive habit: synth-core is a PUBLISHED library and gale asked on #1145 that the refusal NOT be relocated into it (“refusing in the library closes a door gale wants open”; v0.81 built that relocation anyway and reverted it). So a library caller can hand this a malformed log2 that no CLI refusal has seen, and 1u32 << 40 is a debug panic and a release wrap. A getter must be TOTAL.

pub fn initial_bytes(&self) -> u32

Get initial size in bytes.

TWIN with Self::max_bytes (#1441): both read page_bytes() and both saturate. They are listed together because fixing one and not the other is this repo’s recorded twin shape — v0.70 narrowed the integer allocator check and v0.71 found its VFP twin still wrong — and because a memory whose INITIAL honours the declaration while its MAX does not reserves the over-granted extent anyway, which is #1315’s silent over-grant wearing the fix’s clothes.

pub fn max_bytes(&self) -> u32

Get maximum size in bytes (or initial if not specified).

TWIN with Self::initial_bytes — see the note there.

Trait Implementations

impl Clone for WasmMemory

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for WasmMemory

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

Formats the value using the given formatter.