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// This file contains code from external sources.
// Attributions: https://github.com/wasmerio/wasmer/blob/master/ATTRIBUTIONS.md
use crate::instance::ImportFunctionEnv;
use crate::vmcontext::{VMFunctionImport, VMGlobalImport, VMMemoryImport, VMTableImport};
use wasmer_types::entity::{BoxedSlice, PrimaryMap};
use wasmer_types::{FunctionIndex, GlobalIndex, MemoryIndex, TableIndex};
/// Resolved import pointers.
#[derive(Clone)]
pub struct Imports {
/// Resolved addresses for imported functions.
pub functions: BoxedSlice<FunctionIndex, VMFunctionImport>,
/// Initializers for host function environments. This is split out from `functions`
/// because the generated code never needs to touch this and the extra wasted
/// space may affect Wasm runtime performance due to increased cache pressure.
///
/// We make it optional so that we can free the data after use.
///
/// We move this data in `get_imported_function_envs` because there's
/// no value to keeping it around; host functions must be initialized
/// exactly once so we save some memory and improve correctness by
/// moving this data.
pub host_function_env_initializers: Option<BoxedSlice<FunctionIndex, ImportFunctionEnv>>,
/// Resolved addresses for imported tables.
pub tables: BoxedSlice<TableIndex, VMTableImport>,
/// Resolved addresses for imported memories.
pub memories: BoxedSlice<MemoryIndex, VMMemoryImport>,
/// Resolved addresses for imported globals.
pub globals: BoxedSlice<GlobalIndex, VMGlobalImport>,
}
impl Imports {
/// Construct a new `Imports` instance.
pub fn new(
function_imports: PrimaryMap<FunctionIndex, VMFunctionImport>,
host_function_env_initializers: PrimaryMap<FunctionIndex, ImportFunctionEnv>,
table_imports: PrimaryMap<TableIndex, VMTableImport>,
memory_imports: PrimaryMap<MemoryIndex, VMMemoryImport>,
global_imports: PrimaryMap<GlobalIndex, VMGlobalImport>,
) -> Self {
Self {
functions: function_imports.into_boxed_slice(),
host_function_env_initializers: Some(host_function_env_initializers.into_boxed_slice()),
tables: table_imports.into_boxed_slice(),
memories: memory_imports.into_boxed_slice(),
globals: global_imports.into_boxed_slice(),
}
}
/// Construct a new `Imports` instance with no imports.
pub fn none() -> Self {
Self {
functions: PrimaryMap::new().into_boxed_slice(),
host_function_env_initializers: None,
tables: PrimaryMap::new().into_boxed_slice(),
memories: PrimaryMap::new().into_boxed_slice(),
globals: PrimaryMap::new().into_boxed_slice(),
}
}
/// Get the `WasmerEnv::init_with_instance` function pointers and the pointers
/// to the envs to call it on.
///
/// This function can only be called once, it deletes the data it returns after
/// returning it to ensure that it's not called more than once.
pub fn get_imported_function_envs(&mut self) -> BoxedSlice<FunctionIndex, ImportFunctionEnv> {
self.host_function_env_initializers
.take()
.unwrap_or_else(|| PrimaryMap::new().into_boxed_slice())
}
}