cranelift: Merge `abi` and `abi_impl` modules (#4805)

cranelift/codegen/src/isa/aarch64/abi.rs

@@ -617,7 +617,7 @@ impl ABIMachineSpec for AArch64MachineDeps {
     }
 
     // Returns stack bytes used as well as instructions. Does not adjust
-    // nominal SP offset; abi_impl generic code will do that.
+    // nominal SP offset; abi generic code will do that.
     fn gen_clobber_save(
         _call_conv: isa::CallConv,
         setup_frame: bool,

cranelift/codegen/src/isa/s390x/abi.rs

@@ -1,6 +1,6 @@
 //! Implementation of a standard S390x ABI.
 //!
-//! This machine uses the "vanilla" ABI implementation from abi_impl.rs,
+//! This machine uses the "vanilla" ABI implementation from abi.rs,
 //! however a few details are different from the description there:
 //!
 //! - On s390x, the caller must provide a "register save area" of 160
@@ -575,7 +575,7 @@ impl ABIMachineSpec for S390xMachineDeps {
     }
 
     // Returns stack bytes used as well as instructions. Does not adjust
-    // nominal SP offset; abi_impl generic code will do that.
+    // nominal SP offset; abi generic code will do that.
     fn gen_clobber_save(
         _call_conv: isa::CallConv,
         _setup_frame: bool,

cranelift/codegen/src/isa/s390x/lower/isle.rs

@@ -21,7 +21,7 @@ use crate::{
     },
     isa::unwind::UnwindInst,
     isa::CallConv,
-    machinst::abi_impl::ABIMachineSpec,
+    machinst::abi::ABIMachineSpec,
     machinst::{InsnOutput, Lower, MachInst, VCodeConstant, VCodeConstantData},
 };
 use regalloc2::PReg;

cranelift/codegen/src/isa/x64/abi.rs

@@ -4,7 +4,7 @@ use crate::ir::{self, types, LibCall, MemFlags, Opcode, Signature, TrapCode, Typ
 use crate::ir::{types::*, ExternalName};
 use crate::isa;
 use crate::isa::{unwind::UnwindInst, x64::inst::*, x64::settings as x64_settings, CallConv};
-use crate::machinst::abi_impl::*;
+use crate::machinst::abi::*;
 use crate::machinst::*;
 use crate::settings;
 use crate::{CodegenError, CodegenResult};

cranelift/codegen/src/machinst/mod.rs

@@ -73,8 +73,6 @@ pub mod blockorder;
 pub use blockorder::*;
 pub mod abi;
 pub use abi::*;
-pub mod abi_impl;
-pub use abi_impl::*;
 pub mod buffer;
 pub use buffer::*;
 pub mod helpers;