ARM64 backend, part 2 / 11: remove old ARM64 backend.

This removes the old ARM64 backend completely, leaving only an empty
`arm64` module. The tree at this state will not build with the `arm64`
feature enabled, but that feature has to be enabled explicitly (it is
not default). Subsequent patches will fill in the new backend.

cranelift/codegen/src/isa/arm64/abi.rs

@@ -1,31 +0,0 @@
-//! ARM 64 ABI implementation.
-
-use super::registers::{FPR, GPR};
-use crate::ir;
-use crate::isa::RegClass;
-use crate::regalloc::RegisterSet;
-use crate::settings as shared_settings;
-use alloc::borrow::Cow;
-
-/// Legalize `sig`.
-pub fn legalize_signature(
-    _sig: &mut Cow<ir::Signature>,
-    _flags: &shared_settings::Flags,
-    _current: bool,
-) {
-    unimplemented!()
-}
-
-/// Get register class for a type appearing in a legalized signature.
-pub fn regclass_for_abi_type(ty: ir::Type) -> RegClass {
-    if ty.is_int() {
-        GPR
-    } else {
-        FPR
-    }
-}
-
-/// Get the set of allocatable registers for `func`.
-pub fn allocatable_registers(_func: &ir::Function) -> RegisterSet {
-    unimplemented!()
-}

cranelift/codegen/src/isa/arm64/binemit.rs

@@ -1,8 +0,0 @@
-//! Emitting binary ARM64 machine code.
-
-use crate::binemit::{bad_encoding, CodeSink};
-use crate::ir::{Function, Inst};
-use crate::isa::TargetIsa;
-use crate::regalloc::RegDiversions;
-
-include!(concat!(env!("OUT_DIR"), "/binemit-arm64.rs"));

cranelift/codegen/src/isa/arm64/enc_tables.rs

@@ -1,10 +0,0 @@
-//! Encoding tables for ARM64 ISA.
-
-use crate::ir;
-use crate::isa;
-use crate::isa::constraints::*;
-use crate::isa::enc_tables::*;
-use crate::isa::encoding::RecipeSizing;
-
-include!(concat!(env!("OUT_DIR"), "/encoding-arm64.rs"));
-include!(concat!(env!("OUT_DIR"), "/legalize-arm64.rs"));

cranelift/codegen/src/isa/arm64/mod.rs

@@ -1,132 +1 @@
-//! ARM 64-bit Instruction Set Architecture.
+// Empty.
-
-mod abi;
-mod binemit;
-mod enc_tables;
-mod registers;
-pub mod settings;
-
-use super::super::settings as shared_settings;
-#[cfg(feature = "testing_hooks")]
-use crate::binemit::CodeSink;
-use crate::binemit::{emit_function, MemoryCodeSink};
-use crate::ir;
-use crate::isa::enc_tables::{lookup_enclist, Encodings};
-use crate::isa::Builder as IsaBuilder;
-use crate::isa::{EncInfo, RegClass, RegInfo, TargetIsa};
-use crate::regalloc;
-use alloc::borrow::Cow;
-use alloc::boxed::Box;
-use core::fmt;
-use target_lexicon::Triple;
-
-#[allow(dead_code)]
-struct Isa {
-    triple: Triple,
-    shared_flags: shared_settings::Flags,
-    isa_flags: settings::Flags,
-}
-
-/// Get an ISA builder for creating ARM64 targets.
-pub fn isa_builder(triple: Triple) -> IsaBuilder {
-    IsaBuilder {
-        triple,
-        setup: settings::builder(),
-        constructor: isa_constructor,
-    }
-}
-
-fn isa_constructor(
-    triple: Triple,
-    shared_flags: shared_settings::Flags,
-    builder: shared_settings::Builder,
-) -> Box<dyn TargetIsa> {
-    Box::new(Isa {
-        triple,
-        isa_flags: settings::Flags::new(&shared_flags, builder),
-        shared_flags,
-    })
-}
-
-impl TargetIsa for Isa {
-    fn name(&self) -> &'static str {
-        "arm64"
-    }
-
-    fn triple(&self) -> &Triple {
-        &self.triple
-    }
-
-    fn flags(&self) -> &shared_settings::Flags {
-        &self.shared_flags
-    }
-
-    fn register_info(&self) -> RegInfo {
-        registers::INFO.clone()
-    }
-
-    fn encoding_info(&self) -> EncInfo {
-        enc_tables::INFO.clone()
-    }
-
-    fn legal_encodings<'a>(
-        &'a self,
-        func: &'a ir::Function,
-        inst: &'a ir::InstructionData,
-        ctrl_typevar: ir::Type,
-    ) -> Encodings<'a> {
-        lookup_enclist(
-            ctrl_typevar,
-            inst,
-            func,
-            &enc_tables::LEVEL1_A64[..],
-            &enc_tables::LEVEL2[..],
-            &enc_tables::ENCLISTS[..],
-            &enc_tables::LEGALIZE_ACTIONS[..],
-            &enc_tables::RECIPE_PREDICATES[..],
-            &enc_tables::INST_PREDICATES[..],
-            self.isa_flags.predicate_view(),
-        )
-    }
-
-    fn legalize_signature(&self, sig: &mut Cow<ir::Signature>, current: bool) {
-        abi::legalize_signature(sig, &self.shared_flags, current)
-    }
-
-    fn regclass_for_abi_type(&self, ty: ir::Type) -> RegClass {
-        abi::regclass_for_abi_type(ty)
-    }
-
-    fn allocatable_registers(&self, func: &ir::Function) -> regalloc::RegisterSet {
-        abi::allocatable_registers(func)
-    }
-
-    #[cfg(feature = "testing_hooks")]
-    fn emit_inst(
-        &self,
-        func: &ir::Function,
-        inst: ir::Inst,
-        divert: &mut regalloc::RegDiversions,
-        sink: &mut dyn CodeSink,
-    ) {
-        binemit::emit_inst(func, inst, divert, sink, self)
-    }
-
-    fn emit_function_to_memory(&self, func: &ir::Function, sink: &mut MemoryCodeSink) {
-        emit_function(func, binemit::emit_inst, sink, self)
-    }
-
-    fn unsigned_add_overflow_condition(&self) -> ir::condcodes::IntCC {
-        ir::condcodes::IntCC::UnsignedLessThan
-    }
-
-    fn unsigned_sub_overflow_condition(&self) -> ir::condcodes::IntCC {
-        ir::condcodes::IntCC::UnsignedGreaterThanOrEqual
-    }
-}
-
-impl fmt::Display for Isa {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}\n{}", self.shared_flags, self.isa_flags)
-    }
-}

cranelift/codegen/src/isa/arm64/registers.rs

@@ -1,39 +0,0 @@
-//! ARM64 register descriptions.
-
-use crate::isa::registers::{RegBank, RegClass, RegClassData, RegInfo, RegUnit};
-
-include!(concat!(env!("OUT_DIR"), "/registers-arm64.rs"));
-
-#[cfg(test)]
-mod tests {
-    use super::INFO;
-    use crate::isa::RegUnit;
-    use alloc::string::{String, ToString};
-
-    #[test]
-    fn unit_encodings() {
-        assert_eq!(INFO.parse_regunit("x0"), Some(0));
-        assert_eq!(INFO.parse_regunit("x31"), Some(31));
-        assert_eq!(INFO.parse_regunit("v0"), Some(32));
-        assert_eq!(INFO.parse_regunit("v31"), Some(63));
-
-        assert_eq!(INFO.parse_regunit("x32"), None);
-        assert_eq!(INFO.parse_regunit("v32"), None);
-    }
-
-    #[test]
-    fn unit_names() {
-        fn uname(ru: RegUnit) -> String {
-            INFO.display_regunit(ru).to_string()
-        }
-
-        assert_eq!(uname(0), "%x0");
-        assert_eq!(uname(1), "%x1");
-        assert_eq!(uname(31), "%x31");
-        assert_eq!(uname(32), "%v0");
-        assert_eq!(uname(33), "%v1");
-        assert_eq!(uname(63), "%v31");
-        assert_eq!(uname(64), "%nzcv");
-        assert_eq!(uname(65), "%INVALID65");
-    }
-}

cranelift/codegen/src/isa/arm64/settings.rs

@@ -1,9 +0,0 @@
-//! ARM64 Settings.
-
-use crate::settings::{self, detail, Builder};
-use core::fmt;
-
-// Include code generated by `cranelift-codegen/meta/src/gen_settings.rs`. This file contains a
-// public `Flags` struct with an impl for all of the settings defined in
-// `cranelift-codegen/meta/src/isa/arm64/mod.rs`.
-include!(concat!(env!("OUT_DIR"), "/settings-arm64.rs"));

cranelift/codegen/src/isa/mod.rs

@@ -116,7 +116,6 @@ pub fn lookup(triple: Triple) -> Result<Builder, LookupError> {
             isa_builder!(x86, "x86", triple)
         }
         Architecture::Arm { .. } => isa_builder!(arm32, "arm32", triple),
-        Architecture::Aarch64 { .. } => isa_builder!(arm64, "arm64", triple),
         _ => Err(LookupError::Unsupported),
     }
 }