1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120

use crate::{Module, ModuleType, PrimaryMap, TypeConvert, WasmFuncType, WasmHeapType};
use serde_derive::{Deserialize, Serialize};
use std::collections::HashMap;
use std::ops::Index;
use wasmparser::types::CoreTypeId;
use wasmparser::UnpackedIndex;
use wasmtime_types::{ModuleInternedTypeIndex, TypeIndex};

/// All types used in a core wasm module.
///
/// At this time this only contains function types. Note, though, that function
/// types are deduplicated within this [`ModuleTypes`].
///
/// Note that accesing this type is primarily done through the `Index`
/// implementations for this type.
#[derive(Default, Serialize, Deserialize)]
#[allow(missing_docs)]
pub struct ModuleTypes {
    wasm_types: PrimaryMap<ModuleInternedTypeIndex, WasmFuncType>,
}

impl ModuleTypes {
    /// Returns an iterator over all the wasm function signatures found within
    /// this module.
    pub fn wasm_types(&self) -> impl Iterator<Item = (ModuleInternedTypeIndex, &WasmFuncType)> {
        self.wasm_types.iter()
    }
}

impl Index<ModuleInternedTypeIndex> for ModuleTypes {
    type Output = WasmFuncType;

    fn index(&self, sig: ModuleInternedTypeIndex) -> &WasmFuncType {
        &self.wasm_types[sig]
    }
}

/// A builder for [`ModuleTypes`].
#[derive(Default)]
#[allow(missing_docs)]
pub struct ModuleTypesBuilder {
    types: ModuleTypes,
    interned_func_types: HashMap<WasmFuncType, ModuleInternedTypeIndex>,
    wasmparser_to_wasmtime: HashMap<CoreTypeId, ModuleInternedTypeIndex>,
}

impl ModuleTypesBuilder {
    /// Reserves space for `amt` more type signatures.
    pub fn reserve_wasm_signatures(&mut self, amt: usize) {
        self.types.wasm_types.reserve(amt);
    }

    /// Interns the `sig` specified and returns a unique `SignatureIndex` that
    /// can be looked up within [`ModuleTypes`] to recover the [`WasmFuncType`]
    /// at runtime.
    pub fn wasm_func_type(&mut self, id: CoreTypeId, sig: WasmFuncType) -> ModuleInternedTypeIndex {
        let sig = self.intern_func_type(sig);
        self.wasmparser_to_wasmtime.insert(id, sig);
        sig
    }

    fn intern_func_type(&mut self, sig: WasmFuncType) -> ModuleInternedTypeIndex {
        if let Some(idx) = self.interned_func_types.get(&sig) {
            return *idx;
        }

        let idx = self.types.wasm_types.push(sig.clone());
        self.interned_func_types.insert(sig, idx);
        return idx;
    }

    /// Returns the result [`ModuleTypes`] of this builder.
    pub fn finish(self) -> ModuleTypes {
        self.types
    }

    /// Returns an iterator over all the wasm function signatures found within
    /// this module.
    pub fn wasm_signatures(
        &self,
    ) -> impl Iterator<Item = (ModuleInternedTypeIndex, &WasmFuncType)> {
        self.types.wasm_types()
    }
}

// Forward the indexing impl to the internal `ModuleTypes`
impl<T> Index<T> for ModuleTypesBuilder
where
    ModuleTypes: Index<T>,
{
    type Output = <ModuleTypes as Index<T>>::Output;

    fn index(&self, sig: T) -> &Self::Output {
        &self.types[sig]
    }
}

#[allow(missing_docs)]
pub struct WasmparserTypeConverter<'a> {
    pub types: &'a ModuleTypesBuilder,
    pub module: &'a Module,
}

impl TypeConvert for WasmparserTypeConverter<'_> {
    fn lookup_heap_type(&self, index: UnpackedIndex) -> WasmHeapType {
        match index {
            UnpackedIndex::Id(id) => {
                let signature = self.types.wasmparser_to_wasmtime[&id];
                WasmHeapType::TypedFunc(signature)
            }
            UnpackedIndex::RecGroup(_) => unreachable!(),
            UnpackedIndex::Module(i) => {
                let i = TypeIndex::from_u32(i);
                match self.module.types[i] {
                    ModuleType::Function(sig) => WasmHeapType::TypedFunc(sig),
                }
            }
        }
    }
}