cranelift_interpreter/
environment.rs

1//! Implements the function environment (e.g. a name-to-function mapping) for interpretation.
2use cranelift_codegen::ir::{FuncRef, Function};
3use cranelift_entity::{entity_impl, PrimaryMap};
4use std::collections::HashMap;
5
6/// A function store contains all of the functions that are accessible to an interpreter.
7#[derive(Default, Clone)]
8pub struct FunctionStore<'a> {
9    functions: PrimaryMap<FuncIndex, &'a Function>,
10    function_names: HashMap<String, FuncIndex>,
11}
12
13/// An opaque reference to a [`Function`] stored in the [FunctionStore].
14#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
15pub struct FuncIndex(u32);
16entity_impl!(FuncIndex, "fn");
17
18/// This is a helpful conversion for instantiating a store from a single [Function].
19impl<'a> From<&'a Function> for FunctionStore<'a> {
20    fn from(function: &'a Function) -> Self {
21        let mut store = FunctionStore::default();
22        store.add(function.name.to_string(), function);
23        store
24    }
25}
26
27impl<'a> FunctionStore<'a> {
28    /// Add a function by name.
29    pub fn add(&mut self, name: String, function: &'a Function) {
30        assert!(!self.function_names.contains_key(&name));
31        let index = self.functions.push(function);
32        self.function_names.insert(name, index);
33    }
34
35    /// Retrieve the index of a function in the function store by its `name`.
36    pub fn index_of(&self, name: &str) -> Option<FuncIndex> {
37        self.function_names.get(name).cloned()
38    }
39
40    /// Retrieve a function by its index in the function store.
41    pub fn get_by_index(&self, index: FuncIndex) -> Option<&'a Function> {
42        self.functions.get(index).cloned()
43    }
44
45    /// Retrieve a function by its name.
46    pub fn get_by_name(&self, name: &str) -> Option<&'a Function> {
47        let index = self.index_of(name)?;
48        self.get_by_index(index)
49    }
50
51    /// Retrieve a function from a [FuncRef] within a [Function]. TODO this should be optimized, if possible, as
52    /// currently it retrieves the function name as a string and performs string matching.
53    pub fn get_from_func_ref(
54        &self,
55        func_ref: FuncRef,
56        function: &Function,
57    ) -> Option<&'a Function> {
58        self.get_by_name(&get_function_name(func_ref, function))
59    }
60}
61
62/// Retrieve a function name from a [FuncRef] within a [Function]. TODO this should be optimized, if possible, as
63/// currently it retrieves the function name as a string and performs string matching.
64fn get_function_name(func_ref: FuncRef, function: &Function) -> String {
65    function
66        .stencil
67        .dfg
68        .ext_funcs
69        .get(func_ref)
70        .expect("function to exist")
71        .name
72        .display(Some(&function.params))
73        .to_string()
74}
75
76#[cfg(test)]
77mod tests {
78    use super::*;
79    use cranelift_codegen::ir::{Signature, UserFuncName};
80    use cranelift_codegen::isa::CallConv;
81
82    #[test]
83    fn addition() {
84        let mut env = FunctionStore::default();
85        let a = "a";
86        let f = Function::new();
87
88        env.add(a.to_string(), &f);
89        assert!(env.get_by_name(a).is_some());
90    }
91
92    #[test]
93    fn nonexistence() {
94        let env = FunctionStore::default();
95        assert!(env.get_by_name("a").is_none());
96    }
97
98    #[test]
99    fn from() {
100        let name = UserFuncName::testcase("test");
101        let signature = Signature::new(CallConv::Fast);
102        let func = &Function::with_name_signature(name, signature);
103        let env: FunctionStore = func.into();
104        assert_eq!(env.index_of("%test"), Some(FuncIndex::from_u32(0)));
105    }
106}
cranelift_interpreter/environment.rs

cranelift_interpreter/
environment.rs
