Opt-out from fast instance reuse and foundation for other refactorings (#8394)

* Establish the runtime_blob module

Seed it with the existing contents of the `util` module.

* Port wasmtime mutable globals instrumentation into runtime blob APIs

* Opt-out from fast instance reuse

* Minor clean up

* Spaces

* Docs clean up

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Factor out the expects

* Fix the suggestion

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/client/executor/wasmtime/src/util.rs

@@ -18,6 +18,8 @@
 
 use std::ops::Range;
 
+use sp_wasm_interface::Value;
+
 /// Construct a range from an offset to a data length after the offset.
 /// Returns None if the end of the range would exceed some maximum offset.
 pub fn checked_range(offset: usize, len: usize, max: usize) -> Option<Range<usize>> {
@@ -28,3 +30,26 @@ pub fn checked_range(offset: usize, len: usize, max: usize) -> Option<Range<usiz
 		None
 	}
 }
+
+/// Converts a [`wasmtime::Val`] into a substrate runtime interface [`Value`].
+///
+/// Panics if the given value doesn't have a corresponding variant in `Value`.
+pub fn from_wasmtime_val(val: wasmtime::Val) -> Value {
+	match val {
+		wasmtime::Val::I32(v) => Value::I32(v),
+		wasmtime::Val::I64(v) => Value::I64(v),
+		wasmtime::Val::F32(f_bits) => Value::F32(f_bits),
+		wasmtime::Val::F64(f_bits) => Value::F64(f_bits),
+		v => panic!("Given value type is unsupported by Substrate: {:?}", v),
+	}
+}
+
+/// Converts a sp_wasm_interface's [`Value`] into the corresponding variant in wasmtime's [`wasmtime::Val`].
+pub fn into_wasmtime_val(value: Value) -> wasmtime::Val {
+	match value {
+		Value::I32(v) => wasmtime::Val::I32(v),
+		Value::I64(v) => wasmtime::Val::I64(v),
+		Value::F32(f_bits) => wasmtime::Val::F32(f_bits),
+		Value::F64(f_bits) => wasmtime::Val::F64(f_bits),
+	}
+}