Enum wasmtime_environ::MemoryInitialization [−][src]
pub enum MemoryInitialization { Segmented(Vec<MemoryInitializer>), Paged { map: PrimaryMap<DefinedMemoryIndex, Vec<Option<Box<[u8]>>>>, out_of_bounds: bool, }, }
Expand description
The type of WebAssembly linear memory initialization to use for a module.
Variants
Segmented(Vec<MemoryInitializer>)
Memory initialization is segmented.
Segmented initialization can be used for any module, but it is required if:
- A data segment referenced an imported memory.
- A data segment uses a global base.
Segmented initialization is performed by processing the complete set of data segments when the module is instantiated.
This is the default memory initialization type.
Memory initialization is paged.
To be paged, the following requirements must be met:
- All data segments must reference defined memories.
- All data segments must not use a global base.
Paged initialization is performed by copying (or mapping) entire WebAssembly pages to each linear memory.
The uffd
feature makes use of this type of memory initialization because it can instruct the kernel
to back an entire WebAssembly page from an existing set of in-memory pages.
By processing the data segments at module compilation time, the uffd fault handler doesn’t have to do any work to point the kernel at the right linear memory page to use.
Show fields
Fields of Paged
map: PrimaryMap<DefinedMemoryIndex, Vec<Option<Box<[u8]>>>>
The map of defined memory index to a list of initialization pages. The list of page data is sparse, with None representing a zero page. Each page of initialization data is WebAssembly page-sized (64 KiB). The size of the list will be the maximum page written to by a data segment.
out_of_bounds: bool
Whether or not an out-of-bounds data segment was observed. This is used to fail module instantiation after the pages are initialized.
Implementations
Trait Implementations
impl Clone for MemoryInitialization
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impl Clone for MemoryInitialization
[src]fn clone(&self) -> MemoryInitialization
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fn clone(&self) -> MemoryInitialization
[src]Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0[src]
fn clone_from(&mut self, source: &Self)
1.0.0[src]Performs copy-assignment from source
. Read more
impl Debug for MemoryInitialization
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impl Debug for MemoryInitialization
[src]impl Default for MemoryInitialization
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impl Default for MemoryInitialization
[src]impl<'de> Deserialize<'de> for MemoryInitialization
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impl<'de> Deserialize<'de> for MemoryInitialization
[src]fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error> where
__D: Deserializer<'de>,
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fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error> where
__D: Deserializer<'de>,
[src]Deserialize this value from the given Serde deserializer. Read more
impl Serialize for MemoryInitialization
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impl Serialize for MemoryInitialization
[src]Auto Trait Implementations
impl RefUnwindSafe for MemoryInitialization
impl Send for MemoryInitialization
impl Sync for MemoryInitialization
impl Unpin for MemoryInitialization
impl UnwindSafe for MemoryInitialization
Blanket Implementations
impl<T> BorrowMut<T> for T where
T: ?Sized,
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impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]pub fn borrow_mut(&mut self) -> &mut T
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pub fn borrow_mut(&mut self) -> &mut T
[src]Mutably borrows from an owned value. Read more
impl<T> ToOwned for T where
T: Clone,
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impl<T> ToOwned for T where
T: Clone,
[src]type Owned = T
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn to_owned(&self) -> T
[src]Creates owned data from borrowed data, usually by cloning. Read more
pub fn clone_into(&self, target: &mut T)
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pub fn clone_into(&self, target: &mut T)
[src]🔬 This is a nightly-only experimental API. (toowned_clone_into
)
recently added
Uses borrowed data to replace owned data, usually by cloning. Read more
impl<T> DeserializeOwned for T where
T: for<'de> Deserialize<'de>,
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T: for<'de> Deserialize<'de>,