[meta] Use a ref-counted pointer to an InstructionFormat in instructions;

This avoids a lot of dereferences, and InstructionFormat are immutable
once they're created. It removes a lot of code that was keeping the
FormatRegistry around, just in case we needed the format. This is more
in line with the way we create Instructions, and make it easy to
reference InstructionFormats in general.

cranelift/codegen/meta/src/isa/riscv/encodings.rs

@@ -13,24 +13,21 @@ use crate::shared::types::Reference::{R32, R64};
 use crate::shared::Definitions as SharedDefinitions;
 
 use super::recipes::RecipeGroup;
-use crate::cdsl::formats::FormatRegistry;
 
 pub(crate) struct PerCpuModeEncodings<'defs> {
     pub inst_pred_reg: InstructionPredicateRegistry,
     pub enc32: Vec<Encoding>,
     pub enc64: Vec<Encoding>,
     recipes: &'defs Recipes,
-    formats: &'defs FormatRegistry,
 }
 
 impl<'defs> PerCpuModeEncodings<'defs> {
-    fn new(recipes: &'defs Recipes, formats: &'defs FormatRegistry) -> Self {
+    fn new(recipes: &'defs Recipes) -> Self {
         Self {
             inst_pred_reg: InstructionPredicateRegistry::new(),
             enc32: Vec::new(),
             enc64: Vec::new(),
             recipes,
-            formats,
         }
     }
     fn enc(
@@ -39,7 +36,7 @@ impl<'defs> PerCpuModeEncodings<'defs> {
         recipe: EncodingRecipeNumber,
         bits: u16,
     ) -> EncodingBuilder {
-        EncodingBuilder::new(inst.into(), recipe, bits, self.formats)
+        EncodingBuilder::new(inst.into(), recipe, bits)
     }
     fn add32(&mut self, encoding: EncodingBuilder) {
         self.enc32
@@ -176,7 +173,7 @@ pub(crate) fn define<'defs>(
     let use_m = isa_settings.predicate_by_name("use_m");
 
     // Definitions.
-    let mut e = PerCpuModeEncodings::new(&recipes.recipes, &shared_defs.format_registry);
+    let mut e = PerCpuModeEncodings::new(&recipes.recipes);
 
     // Basic arithmetic binary instructions are encoded in an R-type instruction.
     for &(inst, inst_imm, f3, f7) in &[
@@ -242,7 +239,7 @@ pub(crate) fn define<'defs>(
                 bound_inst.clone().into(),
                 vec![Expr::Literal(cc), Expr::Var(x), Expr::Var(y)],
             )
-            .inst_predicate(&shared_defs.format_registry, &var_pool)
+            .inst_predicate(&var_pool)
             .unwrap()
         };
 
@@ -339,7 +336,7 @@ pub(crate) fn define<'defs>(
                     Expr::Var(args),
                 ],
             )
-            .inst_predicate(&shared_defs.format_registry, &var_pool)
+            .inst_predicate(&var_pool)
             .unwrap()
         };