memory.rs - source
Description: Source of the Rust file `library/core/src/../../stdarch/crates/core_arch/src/wasm32/memory.rs`.

#
core/stdarch/crates/core_arch/src/wasm32/
memory.rs

    1#[cfg(test)]
    2use stdarch_test::assert_instr;
    3
    4unsafe extern "unadjusted" {
    5    #[link_name = "llvm.wasm.memory.grow"]
    6    fn llvm_memory_grow(mem: u32, pages: usize) -> usize;
    7    #[link_name = "llvm.wasm.memory.size"]
    8    fn llvm_memory_size(mem: u32) -> usize;
    9}
    10
    11/// Corresponding intrinsic to wasm's [`memory.size` instruction][instr]
    12///
    13/// This function, when called, will return the current memory size in units of
    14/// pages. The current WebAssembly page size is 65536 bytes (64 KB).
    15///
    16/// The argument `MEM` is the numerical index of which memory to return the
    17/// size of. Note that currently the WebAssembly specification only supports one
    18/// memory, so it is required that zero is passed in. The argument is present to
    19/// be forward-compatible with future WebAssembly revisions. If a nonzero
    20/// argument is passed to this function it will currently unconditionally abort.
    21///
    22/// [instr]: http://webassembly.github.io/spec/core/exec/instructions.html#exec-memory-size
    23#[inline]
    24#[cfg_attr(test, assert_instr("memory.size", MEM = 0))]
    25#[rustc_legacy_const_generics(0)]
    26#[stable(feature = "simd_wasm32", since = "1.33.0")]
    27#[doc(alias("memory.size"))]
    28pub fn memory_size<const MEM: u32>() -> usize {
    29    static_assert!(MEM == 0);
    30    unsafe { llvm_memory_size(MEM) }
    31}
    32
    33/// Corresponding intrinsic to wasm's [`memory.grow` instruction][instr]
    34///
    35/// This function, when called, will attempt to grow the default linear memory
    36/// by the specified `delta` of pages. The current WebAssembly page size is
    37/// 65536 bytes (64 KB). If memory is successfully grown then the previous size
    38/// of memory, in pages, is returned. If memory cannot be grown then
    39/// `usize::MAX` is returned.
    40///
    41/// The argument `MEM` is the numerical index of which memory to return the
    42/// size of. Note that currently the WebAssembly specification only supports one
    43/// memory, so it is required that zero is passed in. The argument is present to
    44/// be forward-compatible with future WebAssembly revisions. If a nonzero
    45/// argument is passed to this function it will currently unconditionally abort.
    46///
    47/// [instr]: http://webassembly.github.io/spec/core/exec/instructions.html#exec-memory-grow
    48#[inline]
    49#[cfg_attr(test, assert_instr("memory.grow", MEM = 0))]
    50#[rustc_legacy_const_generics(0)]
    51#[stable(feature = "simd_wasm32", since = "1.33.0")]
    52#[doc(alias("memory.grow"))]
    53pub fn memory_grow<const MEM: u32>(delta: usize) -> usize {
    54    unsafe {
    55        static_assert!(MEM == 0);
    56        llvm_memory_grow(MEM, delta)
    57    }
    58}