Struct wasm::execution::lut::Lut

pub struct Lut {
    function_lut: Vec<Vec<(usize, usize)>>,
}

Fields

function_lut: Vec<Vec<(usize, usize)>>

function_lut[local_module_idx][function_local_idx] = (foreign_module_idx, function_foreign_idx)

• Module A imports a function “foo”. Inside module A, the function has the index “function_local_idx”. Module A is assigned the index “local_module_idx”.
• Module B exports a function “foo”. Inside module B, the function has the index “function_foreign_idx”. Module B is assigned the index “foreign_module_idx”.

Implementations

impl Lut

pub fn new( modules: &[ExecutionInfo<'_>], module_map: &BTreeMap<String, usize> ) -> Option<Self>

Create a new linker lookup-table.

Arguments

• modules: The modules to link together.
• module_map: A map from module name to module index within the modules array.

Returns

A new linker lookup-table. Can return None if there are import directives that cannot be resolved.

pub fn lookup( &self, module_idx: usize, function_idx: usize ) -> Option<(usize, usize)>

Lookup a function by its module and function index.

Arguments

• module_idx: The index of the module within the modules array passed in Lut::new.
• function_idx: The index of the function within the module. This index is considered in-bounds only if it is an index of an imported function.

Returns

• None, if the indicies are out of bound
• Some(export_module_idx, export_function_idx), where the new indicies are the indicies of the module which contains the implementation of the imported function, and the implementation has the returned index within.

pub fn manual_lookup( modules: &[ExecutionInfo<'_>], module_map: &BTreeMap<String, usize>, module_name: &str, function_name: &str ) -> Option<(usize, usize)>

Manually lookup a function by its module and function name.

This function is used to resolve import directives before the Lut is created, and can be used to resolve imports even after the Lut is created at the cost of speed.

Arguments

• modules: The modules to link together.
• module_map: A map from module name to module index within the modules array.
• module_name: The name of the module which imports the function.
• function_name: The name of the function to import.

Returns

• None, if the module or function is not found.
• Some(export_module_idx, export_function_idx), where the new indicies are the indicies of the module which contains the implementation of the imported function, and the implementation has the returned index within. Note that this function returns the first matching function, if there are multiple functions with the same name.