1 files changed, 70 insertions, 0 deletions
diff --git a/third_party/rust/cranelift-wasm/src/state/module_state.rs b/third_party/rust/cranelift-wasm/src/state/module_state.rs
new file mode 100644
index 0000000000..e1b96b8c82
--- /dev/null
+++ b/third_party/rust/cranelift-wasm/src/state/module_state.rs
@@ -0,0 +1,70 @@
+use crate::environ::{WasmError, WasmResult};
+use crate::translation_utils::SignatureIndex;
+use cranelift_codegen::ir::{types, Type};
+use cranelift_entity::PrimaryMap;
+use std::boxed::Box;
+use std::vec::Vec;
+
+/// Map of signatures to a function's parameter and return types.
+pub(crate) type WasmTypes =
+    PrimaryMap<SignatureIndex, (Box<[wasmparser::Type]>, Box<[wasmparser::Type]>)>;
+
+/// Contains information decoded from the Wasm module that must be referenced
+/// during each Wasm function's translation.
+///
+/// This is only for data that is maintained by `cranelift-wasm` itself, as
+/// opposed to being maintained by the embedder. Data that is maintained by the
+/// embedder is represented with `ModuleEnvironment`.
+#[derive(Debug)]
+pub struct ModuleTranslationState {
+    /// A map containing a Wasm module's original, raw signatures.
+    ///
+    /// This is used for translating multi-value Wasm blocks inside functions,
+    /// which are encoded to refer to their type signature via index.
+    pub(crate) wasm_types: WasmTypes,
+}
+
+fn cranelift_to_wasmparser_type(ty: Type) -> WasmResult<wasmparser::Type> {
+    Ok(match ty {
+        types::I32 => wasmparser::Type::I32,
+        types::I64 => wasmparser::Type::I64,
+        types::F32 => wasmparser::Type::F32,
+        types::F64 => wasmparser::Type::F64,
+        types::R32 | types::R64 => wasmparser::Type::ExternRef,
+        _ => {
+            return Err(WasmError::Unsupported(format!(
+                "Cannot convert Cranelift type to Wasm signature: {:?}",
+                ty
+            )));
+        }
+    })
+}
+
+impl ModuleTranslationState {
+    /// Creates a new empty ModuleTranslationState.
+    pub fn new() -> Self {
+        Self {
+            wasm_types: PrimaryMap::new(),
+        }
+    }
+
+    /// Create a new ModuleTranslationState with the given function signatures,
+    /// provided in terms of Cranelift types. The provided slice of signatures
+    /// is indexed by signature number, and contains pairs of (args, results)
+    /// slices.
+    pub fn from_func_sigs(sigs: &[(&[Type], &[Type])]) -> WasmResult<Self> {
+        let mut wasm_types = PrimaryMap::with_capacity(sigs.len());
+        for &(ref args, ref results) in sigs {
+            let args: Vec<wasmparser::Type> = args
+                .iter()
+                .map(|&ty| cranelift_to_wasmparser_type(ty))
+                .collect::<Result<_, _>>()?;
+            let results: Vec<wasmparser::Type> = results
+                .iter()
+                .map(|&ty| cranelift_to_wasmparser_type(ty))
+                .collect::<Result<_, _>>()?;
+            wasm_types.push((args.into_boxed_slice(), results.into_boxed_slice()));
+        }
+        Ok(Self { wasm_types })
+    }
+}