[meta] Use a type alias for Instruction;

... instead of embedding a Rc<InstructionContent>, just make it a type
alias.

cranelift/codegen/meta/src/cdsl/instructions.rs

@@ -3,7 +3,6 @@ use cranelift_entity::{entity_impl, PrimaryMap};
 use std::collections::HashMap;
 use std::fmt;
 use std::fmt::{Display, Error, Formatter};
-use std::ops;
 use std::rc::Rc;
 
 use crate::cdsl::camel_case;
@@ -152,19 +151,7 @@ pub(crate) struct InstructionContent {
     pub writes_cpu_flags: bool,
 }
 
-#[derive(Clone, Debug)]
-pub(crate) struct Instruction {
-    content: Rc<InstructionContent>,
-}
-
-impl ops::Deref for Instruction {
-    type Target = InstructionContent;
-    fn deref(&self) -> &Self::Target {
-        &*self.content
-    }
-}
-
-impl Instruction {
+impl InstructionContent {
     pub fn snake_name(&self) -> &str {
         if &self.name == "return" {
             "return_"
@@ -185,13 +172,15 @@ impl Instruction {
     }
 }
 
+pub(crate) type Instruction = Rc<InstructionContent>;
+
 impl Bindable for Instruction {
     fn bind(&self, parameter: impl Into<BindParameter>) -> BoundInstruction {
         BoundInstruction::new(self).bind(parameter)
     }
 }
 
-impl fmt::Display for Instruction {
+impl fmt::Display for InstructionContent {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         if self.operands_out.len() > 0 {
             let operands_out = self
@@ -352,8 +341,7 @@ impl InstructionBuilder {
 
         let camel_name = camel_case(&self.name);
 
-        Instruction {
-            content: Rc::new(InstructionContent {
+        Rc::new(InstructionContent {
             name: self.name,
             camel_name,
             opcode_number,
@@ -377,8 +365,7 @@ impl InstructionBuilder {
             can_trap: self.can_trap,
             other_side_effects: self.other_side_effects,
             writes_cpu_flags,
-            }),
-        }
+        })
     }
 }