Remove MachBackend

It is identical to TargetIsa

cranelift/codegen/src/isa/arm32/mod.rs

@@ -2,15 +2,15 @@
 
 use crate::ir::condcodes::IntCC;
 use crate::ir::Function;
-use crate::isa::Builder as IsaBuilder;
+use crate::isa::{Builder as IsaBuilder, TargetIsa};
 use crate::machinst::{
-    compile, MachBackend, MachCompileResult, MachTextSectionBuilder, TargetIsaAdapter,
-    TextSectionBuilder, VCode,
+    compile, MachCompileResult, MachTextSectionBuilder, TextSectionBuilder, VCode,
 };
 use crate::result::CodegenResult;
 use crate::settings;
 
 use alloc::{boxed::Box, vec::Vec};
+use core::fmt;
 use regalloc::{PrettyPrint, RealRegUniverse};
 use target_lexicon::{Architecture, ArmArchitecture, Triple};
 
@@ -53,7 +53,7 @@ impl Arm32Backend {
     }
 }
 
-impl MachBackend for Arm32Backend {
+impl TargetIsa for Arm32Backend {
     fn compile_function(
         &self,
         func: &Function,
@@ -100,6 +100,15 @@ impl MachBackend for Arm32Backend {
         Vec::new()
     }
 
+    #[cfg(feature = "unwind")]
+    fn emit_unwind_info(
+        &self,
+        _result: &MachCompileResult,
+        _kind: crate::machinst::UnwindInfoKind,
+    ) -> CodegenResult<Option<crate::isa::unwind::UnwindInfo>> {
+        Ok(None) // FIXME implement this
+    }
+
     fn unsigned_add_overflow_condition(&self) -> IntCC {
         // Carry flag set.
         IntCC::UnsignedGreaterThanOrEqual
@@ -110,6 +119,16 @@ impl MachBackend for Arm32Backend {
     }
 }
 
+impl fmt::Display for Arm32Backend {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("MachBackend")
+            .field("name", &self.name())
+            .field("triple", &self.triple())
+            .field("flags", &format!("{}", self.flags()))
+            .finish()
+    }
+}
+
 /// Create a new `isa::Builder`.
 pub fn isa_builder(triple: Triple) -> IsaBuilder {
     assert!(match triple.architecture {
@@ -123,7 +142,7 @@ pub fn isa_builder(triple: Triple) -> IsaBuilder {
         setup: settings::builder(),
         constructor: |triple, shared_flags, _| {
             let backend = Arm32Backend::new_with_flags(triple, shared_flags);
-            Box::new(TargetIsaAdapter::new(backend))
+            Box::new(backend)
         },
     }
 }