machinst x64: refactor imports to use rustfmt convention

This change is a pure refactoring--no change to functionality. It removes newlines between the `use ...` statements in the x64 backend so that rustfmt can format them according to its convention. I noticed some files had followed a manual convention but subsequent additions did not seem to fit; this change fixes that and lightly coalesces some of the occurrences of `use a::b; use a::c;` into `use::{b, c}`.

cranelift/codegen/src/isa/x64/inst/args.rs

@@ -1,18 +1,13 @@
 //! Instruction operand sub-components (aka "parts"): definitions and printing.
 
-use std::fmt;
-use std::string::{String, ToString};
-
-use regalloc::{RealRegUniverse, Reg, RegClass, RegUsageCollector, RegUsageMapper};
-
+use super::regs::{self, show_ireg_sized};
+use super::EmitState;
 use crate::ir::condcodes::{FloatCC, IntCC};
 use crate::machinst::*;
-
-use super::{
-    regs::{self, show_ireg_sized},
-    EmitState,
-};
 use core::fmt::Debug;
+use regalloc::{RealRegUniverse, Reg, RegClass, RegUsageCollector, RegUsageMapper};
+use std::fmt;
+use std::string::{String, ToString};
 
 /// A possible addressing mode (amode) that can be used in instructions.
 /// These denote a 64-bit value only.

cranelift/codegen/src/isa/x64/inst/emit_tests.rs

@@ -9,10 +9,9 @@
 //! (cd cranelift/codegen && \
 //! RUST_BACKTRACE=1 cargo test isa::x64::inst::test_x64_insn_encoding_and_printing -- --nocapture)
 
-use alloc::vec::Vec;
-
 use super::*;
 use crate::isa::test_utils;
+use alloc::vec::Vec;
 
 #[test]
 fn test_x64_emit() {

cranelift/codegen/src/isa/x64/inst/mod.rs

@@ -4,21 +4,20 @@
 #![allow(non_snake_case)]
 #![allow(non_camel_case_types)]
 
-use alloc::boxed::Box;
-use alloc::vec::Vec;
-use std::fmt;
-use std::string::{String, ToString};
-
-use regalloc::RegUsageCollector;
-use regalloc::{RealRegUniverse, Reg, RegClass, RegUsageMapper, SpillSlot, VirtualReg, Writable};
-use smallvec::SmallVec;
-
 use crate::binemit::{CodeOffset, Stackmap};
 use crate::ir::types::*;
 use crate::ir::{ExternalName, Opcode, SourceLoc, TrapCode, Type};
 use crate::machinst::*;
-use crate::settings::Flags;
-use crate::{settings, CodegenError, CodegenResult};
+use crate::{settings, settings::Flags, CodegenError, CodegenResult};
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use regalloc::{
+    RealRegUniverse, Reg, RegClass, RegUsageCollector, RegUsageMapper, SpillSlot, VirtualReg,
+    Writable,
+};
+use smallvec::SmallVec;
+use std::fmt;
+use std::string::{String, ToString};
 
 pub mod args;
 mod emit;

cranelift/codegen/src/isa/x64/inst/regs.rs

@@ -10,13 +10,10 @@
 //! Also, they will have to be ABI dependent.  Need to find a way to avoid constructing a universe
 //! for each function we compile.
 
+use crate::{machinst::pretty_print::ShowWithRRU, settings};
 use alloc::vec::Vec;
-use std::string::String;
-
 use regalloc::{RealReg, RealRegUniverse, Reg, RegClass, RegClassInfo, NUM_REG_CLASSES};
-
-use crate::machinst::pretty_print::ShowWithRRU;
-use crate::settings;
+use std::string::String;
 
 // Hardware encodings for a few registers.