Make wasmtime_environ::Module serializable (#2005)

* Define WasmType/WasmFuncType in the Cranelift
* Make `Module` serializable

cranelift/codegen/src/ir/extfunc.rs

@@ -11,6 +11,8 @@ use crate::machinst::RelocDistance;
 use alloc::vec::Vec;
 use core::fmt;
 use core::str::FromStr;
+#[cfg(feature = "enable-serde")]
+use serde::{Deserialize, Serialize};
 
 /// Function signature.
 ///
@@ -20,6 +22,7 @@ use core::str::FromStr;
 /// A signature can optionally include ISA-specific ABI information which specifies exactly how
 /// arguments and return values are passed.
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
 pub struct Signature {
     /// The arguments passed to the function.
     pub params: Vec<AbiParam>,
@@ -145,6 +148,7 @@ impl fmt::Display for Signature {
 /// This describes the value type being passed to or from a function along with flags that affect
 /// how the argument is passed.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
 pub struct AbiParam {
     /// Type of the argument value.
     pub value_type: Type,
@@ -255,6 +259,7 @@ impl fmt::Display for AbiParam {
 /// On some architectures, small integer function arguments are extended to the width of a
 /// general-purpose register.
 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
+#[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
 pub enum ArgumentExtension {
     /// No extension, high bits are indeterminate.
     None,
@@ -272,6 +277,7 @@ pub enum ArgumentExtension {
 ///
 /// The argument purpose is used to indicate any special meaning of an argument or return value.
 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
+#[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
 pub enum ArgumentPurpose {
     /// A normal user program value passed to or from a function.
     Normal,