87b1a85cc6
Prior to this change, the interpreter would use an incorrect `FuncRef` for accessing functions from the function store. This is now clarified and fixed by a new type--`FuncIndex`.
105 lines
3.4 KiB
Rust
105 lines
3.4 KiB
Rust
//! Implements the function environment (e.g. a name-to-function mapping) for interpretation.
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use cranelift_codegen::ir::{FuncRef, Function};
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use cranelift_entity::{entity_impl, PrimaryMap};
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use std::collections::HashMap;
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/// A function store contains all of the functions that are accessible to an interpreter.
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#[derive(Default, Clone)]
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pub struct FunctionStore<'a> {
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functions: PrimaryMap<FuncIndex, &'a Function>,
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function_names: HashMap<String, FuncIndex>,
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}
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/// An opaque reference to a [`Function`](Function) stored in the [FunctionStore].
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#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
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pub struct FuncIndex(u32);
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entity_impl!(FuncIndex, "fn");
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/// This is a helpful conversion for instantiating a store from a single [Function].
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impl<'a> From<&'a Function> for FunctionStore<'a> {
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fn from(function: &'a Function) -> Self {
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let mut store = FunctionStore::default();
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store.add(function.name.to_string(), function);
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store
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}
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}
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impl<'a> FunctionStore<'a> {
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/// Add a function by name.
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pub fn add(&mut self, name: String, function: &'a Function) {
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assert!(!self.function_names.contains_key(&name));
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let index = self.functions.push(function);
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self.function_names.insert(name, index);
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}
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/// Retrieve the index of a function in the function store by its `name`.
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pub fn index_of(&self, name: &str) -> Option<FuncIndex> {
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self.function_names.get(name).cloned()
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}
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/// Retrieve a function by its index in the function store.
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pub fn get_by_index(&self, index: FuncIndex) -> Option<&'a Function> {
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self.functions.get(index).cloned()
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}
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/// Retrieve a function by its name.
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pub fn get_by_name(&self, name: &str) -> Option<&'a Function> {
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let index = self.index_of(name)?;
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self.get_by_index(index)
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}
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/// Retrieve a function from a [FuncRef] within a [Function]. TODO this should be optimized, if possible, as
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/// currently it retrieves the function name as a string and performs string matching.
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pub fn get_from_func_ref(
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&self,
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func_ref: FuncRef,
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function: &Function,
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) -> Option<&'a Function> {
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self.get_by_name(&get_function_name(func_ref, function))
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}
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}
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/// Retrieve a function name from a [FuncRef] within a [Function]. TODO this should be optimized, if possible, as
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/// currently it retrieves the function name as a string and performs string matching.
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fn get_function_name(func_ref: FuncRef, function: &Function) -> String {
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function
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.dfg
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.ext_funcs
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.get(func_ref)
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.expect("function to exist")
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.name
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.to_string()
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use cranelift_codegen::ir::{ExternalName, Signature};
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use cranelift_codegen::isa::CallConv;
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#[test]
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fn addition() {
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let mut env = FunctionStore::default();
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let a = "a";
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let f = Function::new();
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env.add(a.to_string(), &f);
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assert!(env.get_by_name(a).is_some());
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}
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#[test]
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fn nonexistence() {
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let env = FunctionStore::default();
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assert!(env.get_by_name("a").is_none());
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}
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#[test]
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fn from() {
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let name = ExternalName::testcase("test");
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let signature = Signature::new(CallConv::Fast);
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let func = &Function::with_name_signature(name, signature);
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let env: FunctionStore = func.into();
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assert_eq!(env.index_of("%test"), Some(FuncIndex::from_u32(0)));
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}
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}
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