Avoid unneeded passing by value.

https://github.com/rust-lang-nursery/rust-clippy/wiki#needless_pass_by_value

lib/wasm/src/code_translator.rs

@@ -156,7 +156,7 @@ impl FunctionImports {
 pub fn translate_function_body(
     parser: &mut Parser,
     function_index: FunctionIndex,
-    sig: Signature,
+    sig: &Signature,
     locals: &[(usize, Type)],
     exports: &Option<HashMap<FunctionIndex, String>>,
     signatures: &[Signature],

lib/wasm/src/module_translator.rs

@@ -260,7 +260,7 @@ pub fn translate_module(
         match translate_function_body(
             &mut parser,
             function_index,
-            signature,
+            &signature,
             &locals,
             &exports,
             &signatures,
@@ -271,7 +271,7 @@ pub fn translate_module(
             Ok((il_func, imports)) => {
                 il_functions.push(FunctionTranslation::Code {
                     il: il_func,
-                    imports: invert_hashmaps(imports),
+                    imports: invert_hashmaps(&imports),
                 })
             }
             Err(s) => return Err(s),

lib/wasm/src/translation_utils.rs

@@ -140,7 +140,7 @@ pub fn translate_type(ty: wasmparser::Type) -> Result<Vec<cretonne::ir::Type>, (
 /// feeding the function indexes in the module but are used by the runtime with the `FuncRef` as
 /// keys.
 pub fn invert_hashmaps(
-    imports: code_translator::FunctionImports,
+    imports: &code_translator::FunctionImports,
 ) -> module_translator::ImportMappings {
     let mut new_imports = module_translator::ImportMappings::new();
     for (func_index, func_ref) in &imports.functions {