[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/lib.rs

@@ -39,13 +39,7 @@ pub fn generate(isas: &Vec<isa::Isa>, out_dir: &str) -> Result<(), error::Error>
 
     gen_inst::generate(&shared_defs, "opcodes.rs", "inst_builder.rs", &out_dir)?;
 
-    gen_legalizer::generate(
-        &isas,
-        &shared_defs.format_registry,
-        &shared_defs.transform_groups,
-        "legalize",
-        &out_dir,
-    )?;
+    gen_legalizer::generate(&isas, &shared_defs.transform_groups, "legalize", &out_dir)?;
 
     for isa in isas {
         gen_registers::generate(&isa, &format!("registers-{}.rs", isa.name), &out_dir)?;
@@ -65,7 +59,6 @@ pub fn generate(isas: &Vec<isa::Isa>, out_dir: &str) -> Result<(), error::Error>
         )?;
 
         gen_binemit::generate(
-            &shared_defs.format_registry,
             &isa.name,
             &isa.recipes,
             &format!("binemit-{}.rs", isa.name),