Add inline asm register definitions to librustc_target

src/librustc_target/asm/aarch64.rs

+use super::{InlineAsmArch, InlineAsmType};
+use rustc_macros::HashStable_Generic;
+use std::fmt;
+
+def_reg_class! {
+    AArch64 AArch64InlineAsmRegClass {
+        reg,
+        vreg,
+        vreg_low16,
+    }
+}
+
+impl AArch64InlineAsmRegClass {
+    pub fn valid_modifiers(self, _arch: super::InlineAsmArch) -> &'static [char] {
+        match self {
+            Self::reg => &['w', 'x'],
+            Self::vreg | Self::vreg_low16 => &['b', 'h', 's', 'd', 'q', 'v'],
+        }
+    }
+
+    pub fn suggest_modifier(
+        self,
+        _arch: InlineAsmArch,
+        ty: InlineAsmType,
+    ) -> Option<(char, &'static str, Option<&'static str>)> {
+        match self {
+            Self::reg => {
+                if ty.size().bits() <= 32 {
+                    Some(('w', "w0", None))
+                } else {
+                    None
+                }
+            }
+            Self::vreg | Self::vreg_low16 => match ty.size().bits() {
+                8 => Some(('b', "b0", None)),
+                16 => Some(('h', "h0", None)),
+                32 => Some(('s', "s0", None)),
+                64 => Some(('d', "d0", None)),
+                128 => Some(('q', "q0", None)),
+                _ => None,
+            },
+        }
+    }
+
+    pub fn default_modifier(self, _arch: InlineAsmArch) -> Option<(char, &'static str)> {
+        match self {
+            Self::reg => Some(('x', "x0")),
+            Self::vreg | Self::vreg_low16 => Some(('v', "v0")),
+        }
+    }
+
+    pub fn supported_types(
+        self,
+        _arch: InlineAsmArch,
+    ) -> &'static [(InlineAsmType, Option<&'static str>)] {
+        match self {
+            Self::reg => types! { _: I8, I16, I32, I64, F32, F64; },
+            Self::vreg | Self::vreg_low16 => types! {
+                "fp": I8, I16, I32, I64, F32, F64,
+                VecI8(8), VecI16(4), VecI32(2), VecI64(1), VecF32(2), VecF64(1),
+                VecI8(16), VecI16(8), VecI32(4), VecI64(2), VecF32(4), VecF64(2);
+            },
+        }
+    }
+}
+
+def_regs! {
+    AArch64 AArch64InlineAsmReg AArch64InlineAsmRegClass {
+        x0: reg = ["x0", "w0"],
+        x1: reg = ["x1", "w1"],
+        x2: reg = ["x2", "w2"],
+        x3: reg = ["x3", "w3"],
+        x4: reg = ["x4", "w4"],
+        x5: reg = ["x5", "w5"],
+        x6: reg = ["x6", "w6"],
+        x7: reg = ["x7", "w7"],
+        x8: reg = ["x8", "w8"],
+        x9: reg = ["x9", "w9"],
+        x10: reg = ["x10", "w10"],
+        x11: reg = ["x11", "w11"],
+        x12: reg = ["x12", "w12"],
+        x13: reg = ["x13", "w13"],
+        x14: reg = ["x14", "w14"],
+        x15: reg = ["x15", "w15"],
+        x16: reg = ["x16", "w16"],
+        x17: reg = ["x17", "w17"],
+        x18: reg = ["x18", "w18"],
+        x19: reg = ["x19", "w19"],
+        x20: reg = ["x20", "w20"],
+        x21: reg = ["x21", "w21"],
+        x22: reg = ["x22", "w22"],
+        x23: reg = ["x23", "w23"],
+        x24: reg = ["x24", "w24"],
+        x25: reg = ["x25", "w25"],
+        x26: reg = ["x26", "w26"],
+        x27: reg = ["x27", "w27"],
+        x28: reg = ["x28", "w28"],
+        x30: reg = ["x30", "w30", "lr"],
+        v0: vreg, vreg_low16 = ["v0", "b0", "h0", "s0", "d0", "q0"],
+        v1: vreg, vreg_low16 = ["v1", "b1", "h1", "s1", "d1", "q1"],
+        v2: vreg, vreg_low16 = ["v2", "b2", "h2", "s2", "d2", "q2"],
+        v3: vreg, vreg_low16 = ["v3", "b3", "h3", "s3", "d3", "q3"],
+        v4: vreg, vreg_low16 = ["v4", "b4", "h4", "s4", "d4", "q4"],
+        v5: vreg, vreg_low16 = ["v5", "b5", "h5", "s5", "d5", "q5"],
+        v6: vreg, vreg_low16 = ["v6", "b6", "h6", "s6", "d6", "q6"],
+        v7: vreg, vreg_low16 = ["v7", "b7", "h7", "s7", "d7", "q7"],
+        v8: vreg, vreg_low16 = ["v8", "b8", "h8", "s8", "d8", "q8"],
+        v9: vreg, vreg_low16 = ["v9", "b9", "h9", "s9", "d9", "q9"],
+        v10: vreg, vreg_low16 = ["v10", "b10", "h10", "s10", "d10", "q10"],
+        v11: vreg, vreg_low16 = ["v11", "b11", "h11", "s11", "d11", "q11"],
+        v12: vreg, vreg_low16 = ["v12", "b12", "h12", "s12", "d12", "q12"],
+        v13: vreg, vreg_low16 = ["v13", "b13", "h13", "s13", "d13", "q13"],
+        v14: vreg, vreg_low16 = ["v14", "b14", "h14", "s14", "d14", "q14"],
+        v15: vreg, vreg_low16 = ["v15", "b15", "h15", "s15", "d15", "q15"],
+        v16: vreg = ["v16", "b16", "h16", "s16", "d16", "q16"],
+        v17: vreg = ["v17", "b17", "h17", "s17", "d17", "q17"],
+        v18: vreg = ["v18", "b18", "h18", "s18", "d18", "q18"],
+        v19: vreg = ["v19", "b19", "h19", "s19", "d19", "q19"],
+        v20: vreg = ["v20", "b20", "h20", "s20", "d20", "q20"],
+        v21: vreg = ["v21", "b21", "h21", "s21", "d21", "q21"],
+        v22: vreg = ["v22", "b22", "h22", "s22", "d22", "q22"],
+        v23: vreg = ["v23", "b23", "h23", "s23", "d23", "q23"],
+        v24: vreg = ["v24", "b24", "h24", "s24", "d24", "q24"],
+        v25: vreg = ["v25", "b25", "h25", "s25", "d25", "q25"],
+        v26: vreg = ["v26", "b26", "h26", "s26", "d26", "q26"],
+        v27: vreg = ["v27", "b27", "h27", "s27", "d27", "q27"],
+        v28: vreg = ["v28", "b28", "h28", "s28", "d28", "q28"],
+        v29: vreg = ["v29", "b29", "h29", "s29", "d29", "q29"],
+        v30: vreg = ["v30", "b30", "h30", "s30", "d30", "q30"],
+        v31: vreg = ["v31", "b31", "h31", "s31", "d31", "q31"],
+        "the frame pointer cannot be used as an operand for inline asm" =
+            ["x29", "fp"],
+        "the stack pointer cannot be used as an operand for inline asm" =
+            ["sp", "wsp"],
+        "the zero register cannot be used as an operand for inline asm" =
+            ["xzr", "wzr"],
+    }
+}
+
+impl AArch64InlineAsmReg {
+    pub fn emit(
+        self,
+        out: &mut dyn fmt::Write,
+        _arch: InlineAsmArch,
+        modifier: Option<char>,
+    ) -> fmt::Result {
+        let (prefix, index) = if (self as u32) < Self::v0 as u32 {
+            (modifier.unwrap_or('x'), self as u32 - Self::x0 as u32)
+        } else {
+            (modifier.unwrap_or('v'), self as u32 - Self::v0 as u32)
+        };
+        assert!(index < 32);
+        write!(out, "{}{}", prefix, index)
+    }
+}

src/librustc_target/asm/arm.rs

+use super::{InlineAsmArch, InlineAsmType};
+use rustc_macros::HashStable_Generic;
+use std::fmt;
+
+def_reg_class! {
+    Arm ArmInlineAsmRegClass {
+        reg,
+        reg_thumb,
+        sreg,
+        sreg_low16,
+        dreg,
+        dreg_low16,
+        dreg_low8,
+        qreg,
+        qreg_low8,
+        qreg_low4,
+    }
+}
+
+impl ArmInlineAsmRegClass {
+    pub fn valid_modifiers(self, _arch: super::InlineAsmArch) -> &'static [char] {
+        match self {
+            Self::qreg | Self::qreg_low8 | Self::qreg_low4 => &['e', 'f'],
+            _ => &[],
+        }
+    }
+
+    pub fn suggest_modifier(
+        self,
+        _arch: InlineAsmArch,
+        _ty: InlineAsmType,
+    ) -> Option<(char, &'static str, Option<&'static str>)> {
+        None
+    }
+
+    pub fn default_modifier(self, _arch: InlineAsmArch) -> Option<(char, &'static str)> {
+        None
+    }
+
+    pub fn supported_types(
+        self,
+        _arch: InlineAsmArch,
+    ) -> &'static [(InlineAsmType, Option<&'static str>)] {
+        match self {
+            Self::reg | Self::reg_thumb => types! { _: I8, I16, I32, F32; },
+            Self::sreg | Self::sreg_low16 => types! { "vfp2": I32, F32; },
+            Self::dreg | Self::dreg_low16 | Self::dreg_low8 => types! {
+                "vfp2": I64, F64, VecI8(8), VecI16(4), VecI32(2), VecI64(1), VecF32(2);
+            },
+            Self::qreg | Self::qreg_low8 | Self::qreg_low4 => types! {
+                "neon": VecI8(16), VecI16(8), VecI32(4), VecI64(2), VecF32(4);
+            },
+        }
+    }
+}
+
+def_regs! {
+    Arm ArmInlineAsmReg ArmInlineAsmRegClass {
+        r0: reg, reg_thumb = ["r0", "a1"],
+        r1: reg, reg_thumb = ["r1", "a2"],
+        r2: reg, reg_thumb = ["r2", "a3"],
+        r3: reg, reg_thumb = ["r3", "a4"],
+        r4: reg, reg_thumb = ["r4", "v1"],
+        r5: reg, reg_thumb = ["r5", "v2"],
+        r6: reg, reg_thumb = ["r6", "v3"],
+        r7: reg, reg_thumb = ["r7", "v4"],
+        r8: reg = ["r8", "v5"],
+        r9: reg = ["r9", "v6", "rfp"],
+        r10: reg = ["r10", "sl"],
+        r12: reg = ["r12", "ip"],
+        r14: reg = ["r14", "lr"],
+        s0: sreg, sreg_low16 = ["s0"],
+        s1: sreg, sreg_low16 = ["s1"],
+        s2: sreg, sreg_low16 = ["s2"],
+        s3: sreg, sreg_low16 = ["s3"],
+        s4: sreg, sreg_low16 = ["s4"],
+        s5: sreg, sreg_low16 = ["s5"],
+        s6: sreg, sreg_low16 = ["s6"],
+        s7: sreg, sreg_low16 = ["s7"],
+        s8: sreg, sreg_low16 = ["s8"],
+        s9: sreg, sreg_low16 = ["s9"],
+        s10: sreg, sreg_low16 = ["s10"],
+        s11: sreg, sreg_low16 = ["s11"],
+        s12: sreg, sreg_low16 = ["s12"],
+        s13: sreg, sreg_low16 = ["s13"],
+        s14: sreg, sreg_low16 = ["s14"],
+        s15: sreg, sreg_low16 = ["s15"],
+        s16: sreg = ["s16"],
+        s17: sreg = ["s17"],
+        s18: sreg = ["s18"],
+        s19: sreg = ["s19"],
+        s20: sreg = ["s20"],
+        s21: sreg = ["s21"],
+        s22: sreg = ["s22"],
+        s23: sreg = ["s23"],
+        s24: sreg = ["s24"],
+        s25: sreg = ["s25"],
+        s26: sreg = ["s26"],
+        s27: sreg = ["s27"],
+        s28: sreg = ["s28"],
+        s29: sreg = ["s29"],
+        s30: sreg = ["s30"],
+        s31: sreg = ["s31"],
+        d0: dreg, dreg_low16, dreg_low8 = ["d0"],
+        d1: dreg, dreg_low16, dreg_low8 = ["d1"],
+        d2: dreg, dreg_low16, dreg_low8 = ["d2"],
+        d3: dreg, dreg_low16, dreg_low8 = ["d3"],
+        d4: dreg, dreg_low16, dreg_low8 = ["d4"],
+        d5: dreg, dreg_low16, dreg_low8 = ["d5"],
+        d6: dreg, dreg_low16, dreg_low8 = ["d6"],
+        d7: dreg, dreg_low16, dreg_low8 = ["d7"],
+        d8: dreg, dreg_low16 = ["d8"],
+        d9: dreg, dreg_low16 = ["d9"],
+        d10: dreg, dreg_low16 = ["d10"],
+        d11: dreg, dreg_low16 = ["d11"],
+        d12: dreg, dreg_low16 = ["d12"],
+        d13: dreg, dreg_low16 = ["d13"],
+        d14: dreg, dreg_low16 = ["d14"],
+        d15: dreg, dreg_low16 = ["d15"],
+        d16: dreg = ["d16"],
+        d17: dreg = ["d17"],
+        d18: dreg = ["d18"],
+        d19: dreg = ["d19"],
+        d20: dreg = ["d20"],
+        d21: dreg = ["d21"],
+        d22: dreg = ["d22"],
+        d23: dreg = ["d23"],
+        d24: dreg = ["d24"],
+        d25: dreg = ["d25"],
+        d26: dreg = ["d26"],
+        d27: dreg = ["d27"],
+        d28: dreg = ["d28"],
+        d29: dreg = ["d29"],
+        d30: dreg = ["d30"],
+        d31: dreg = ["d31"],
+        q0: qreg, qreg_low8, qreg_low4 = ["q0"],
+        q1: qreg, qreg_low8, qreg_low4 = ["q1"],
+        q2: qreg, qreg_low8, qreg_low4 = ["q2"],
+        q3: qreg, qreg_low8, qreg_low4 = ["q3"],
+        q4: qreg, qreg_low8 = ["q4"],
+        q5: qreg, qreg_low8 = ["q5"],
+        q6: qreg, qreg_low8 = ["q6"],
+        q7: qreg, qreg_low8 = ["q7"],
+        q8: qreg = ["q8"],
+        q9: qreg = ["q9"],
+        q10: qreg = ["q10"],
+        q11: qreg = ["q11"],
+        q12: qreg = ["q12"],
+        q13: qreg = ["q13"],
+        q14: qreg = ["q14"],
+        q15: qreg = ["q15"],
+        "the frame pointer cannot be used as an operand for inline asm" =
+            ["r11", "fp"],
+        "the stack pointer cannot be used as an operand for inline asm" =
+            ["r13", "sp"],
+        "the program pointer cannot be used as an operand for inline asm" =
+            ["r15", "pc"],
+    }
+}
+
+impl ArmInlineAsmReg {
+    pub fn emit(
+        self,
+        out: &mut dyn fmt::Write,
+        _arch: InlineAsmArch,
+        modifier: Option<char>,
+    ) -> fmt::Result {
+        // Only qreg is allowed to have modifiers. This should have been
+        // validated already by now.
+        if let Some(modifier) = modifier {
+            let index = self as u32 - Self::q0 as u32;
+            assert!(index < 16);
+            let index = index * 2 + (modifier == 'f') as u32;
+            write!(out, "d{}", index)
+        } else {
+            out.write_str(self.name())
+        }
+    }
+
+    pub fn overlapping_regs(self, mut cb: impl FnMut(ArmInlineAsmReg)) {
+        cb(self);
+
+        macro_rules! reg_conflicts {
+            (
+                $(
+                    $q:ident : $d0:ident $d1:ident : $s0:ident $s1:ident $s2:ident $s3:ident
+                ),*;
+                $(
+                    $q_high:ident : $d0_high:ident $d1_high:ident
+                ),*;
+            ) => {
+                match self {
+                    $(
+                        Self::$q => {
+                            cb(Self::$d0);
+                            cb(Self::$d1);
+                            cb(Self::$s0);
+                            cb(Self::$s1);
+                            cb(Self::$s2);
+                            cb(Self::$s3);
+                        }
+                        Self::$d0 => {
+                            cb(Self::$q);
+                            cb(Self::$s0);
+                            cb(Self::$s1);
+                        }
+                        Self::$d1 => {
+                            cb(Self::$q);
+                            cb(Self::$s2);
+                            cb(Self::$s3);
+                        }
+                        Self::$s0 | Self::$s1 => {
+                            cb(Self::$q);
+                            cb(Self::$d0);
+                        }
+                        Self::$s2 | Self::$s3 => {
+                            cb(Self::$q);
+                            cb(Self::$d1);
+                        }
+                    )*
+                    $(
+                        Self::$q_high => {
+                            cb(Self::$d0_high);
+                            cb(Self::$d1_high);
+                        }
+                        Self::$d0_high | Self::$d1_high => {
+                            cb(Self::$q_high);
+                        }
+                    )*
+                    _ => {},
+                }
+            };
+        }
+        reg_conflicts! {
+            q0 : d0 d1 : s0 s1 s2 s3,
+            q1 : d2 d3 : s4 s5 s6 s7,
+            q2 : d4 d5 : s8 s9 s10 s11,
+            q3 : d6 d7 : s12 s13 s14 s15,
+            q4 : d8 d9 : s16 s17 s18 s19,
+            q5 : d10 d11 : s20 s21 s22 s23,
+            q6 : d12 d13 : s24 s25 s26 s27,
+            q7 : d14 d15 : s28 s29 s30 s31;
+            q8 : d16 d17,
+            q9 : d18 d19,
+            q10 : d20 d21,
+            q11 : d22 d23,
+            q12 : d24 d25,
+            q13 : d26 d27,
+            q14 : d28 d29,
+            q15 : d30 d31;
+        }
+    }
+}

src/librustc_target/asm/mod.rs

+use crate::abi::Size;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_macros::HashStable_Generic;
+use rustc_span::{Span, Symbol};
+use std::fmt;
+use std::str::FromStr;
+
+#[macro_use]
+macro_rules! def_reg_class {
+    ($arch:ident $arch_regclass:ident {
+        $(
+            $class:ident,
+        )*
+    }) => {
+        #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, Eq, PartialEq, Hash, HashStable_Generic)]
+        #[allow(non_camel_case_types)]
+        pub enum $arch_regclass {
+            $($class,)*
+        }
+
+        impl $arch_regclass {
+            pub fn name(self) -> &'static str {
+                match self {
+                    $(Self::$class => stringify!($class),)*
+                }
+            }
+
+            pub fn parse(_arch: super::InlineAsmArch, name: &str) -> Result<Self, &'static str> {
+                match name {
+                    $(
+                        stringify!($class) => Ok(Self::$class),
+                    )*
+                    _ => Err("unknown register class"),
+                }
+            }
+        }
+
+        pub(super) fn regclass_map() -> rustc_data_structures::fx::FxHashMap<
+            super::InlineAsmRegClass,
+            rustc_data_structures::fx::FxHashSet<super::InlineAsmReg>,
+        > {
+            use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+            use super::InlineAsmRegClass;
+            let mut map = FxHashMap::default();
+            $(
+                map.insert(InlineAsmRegClass::$arch($arch_regclass::$class), FxHashSet::default());
+            )*
+            map
+        }
+    }
+}
+
+#[macro_use]
+macro_rules! def_regs {
+    ($arch:ident $arch_reg:ident $arch_regclass:ident {
+        $(
+            $reg:ident: $class:ident $(, $extra_class:ident)* = [$reg_name:literal $(, $alias:literal)*] $(% $filter:ident)?,
+        )*
+        $(
+            $error:literal = [$($bad_reg:literal),+],
+        )*
+    }) => {
+        #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, Eq, PartialEq, Hash, HashStable_Generic)]
+        #[allow(non_camel_case_types)]
+        pub enum $arch_reg {
+            $($reg,)*
+        }
+
+        impl $arch_reg {
+            pub fn name(self) -> &'static str {
+                match self {
+                    $(Self::$reg => $reg_name,)*
+                }
+            }
+
+            pub fn reg_class(self) -> $arch_regclass {
+                match self {
+                    $(Self::$reg => $arch_regclass::$class,)*
+                }
+            }
+
+            pub fn parse(
+                _arch: super::InlineAsmArch,
+                mut _has_feature: impl FnMut(&str) -> bool,
+                name: &str,
+            ) -> Result<Self, &'static str> {
+                match name {
+                    $(
+                        $($alias)|* | $reg_name => {
+                            $($filter(_arch, &mut _has_feature)?;)?
+                            Ok(Self::$reg)
+                        }
+                    )*
+                    $(
+                        $($bad_reg)|* => Err($error),
+                    )*
+                    _ => Err("unknown register"),
+                }
+            }
+        }
+
+        pub(super) fn fill_reg_map(
+            _arch: super::InlineAsmArch,
+            mut _has_feature: impl FnMut(&str) -> bool,
+            map: &mut rustc_data_structures::fx::FxHashMap<
+                super::InlineAsmRegClass,
+                rustc_data_structures::fx::FxHashSet<super::InlineAsmReg>,
+            >,
+        ) {
+            use super::{InlineAsmReg, InlineAsmRegClass};
+            $(
+                if $($filter(_arch, &mut _has_feature).is_ok() &&)? true {
+                    if let Some(set) = map.get_mut(&InlineAsmRegClass::$arch($arch_regclass::$class)) {
+                        set.insert(InlineAsmReg::$arch($arch_reg::$reg));
+                    }
+                    $(
+                        if let Some(set) = map.get_mut(&InlineAsmRegClass::$arch($arch_regclass::$extra_class)) {
+                            set.insert(InlineAsmReg::$arch($arch_reg::$reg));
+                        }
+                    )*
+                }
+            )*
+        }
+    }
+}
+
+#[macro_use]
+macro_rules! types {
+    (
+        $(_ : $($ty:expr),+;)?
+        $($feature:literal: $($ty2:expr),+;)*
+    ) => {
+        {
+            use super::InlineAsmType::*;
+            &[
+                $($(
+                    ($ty, None),
+                )*)?
+                $($(
+                    ($ty2, Some($feature)),
+                )*)*
+            ]
+        }
+    };
+}
+
+mod aarch64;
+mod arm;
+mod riscv;
+mod x86;
+
+pub use aarch64::{AArch64InlineAsmReg, AArch64InlineAsmRegClass};
+pub use arm::{ArmInlineAsmReg, ArmInlineAsmRegClass};
+pub use riscv::{RiscVInlineAsmReg, RiscVInlineAsmRegClass};
+pub use x86::{X86InlineAsmReg, X86InlineAsmRegClass};
+
+#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, Eq, PartialEq, Hash)]
+pub enum InlineAsmArch {
+    X86,
+    X86_64,
+    Arm,
+    AArch64,
+    RiscV32,
+    RiscV64,
+}
+
+impl FromStr for InlineAsmArch {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<InlineAsmArch, ()> {
+        match s {
+            "x86" => Ok(Self::X86),
+            "x86_64" => Ok(Self::X86_64),
+            "arm" => Ok(Self::Arm),
+            "aarch64" => Ok(Self::AArch64),
+            "riscv32" => Ok(Self::RiscV32),
+            "riscv64" => Ok(Self::RiscV64),
+            _ => Err(()),
+        }
+    }
+}
+
+#[derive(
+    Copy,
+    Clone,
+    RustcEncodable,
+    RustcDecodable,
+    Debug,
+    Eq,
+    PartialEq,
+    Hash,
+    HashStable_Generic
+)]
+pub enum InlineAsmReg {
+    X86(X86InlineAsmReg),
+    Arm(ArmInlineAsmReg),
+    AArch64(AArch64InlineAsmReg),
+    RiscV(RiscVInlineAsmReg),
+}
+
+impl InlineAsmReg {
+    pub fn name(self) -> &'static str {
+        match self {
+            Self::X86(r) => r.name(),
+            Self::Arm(r) => r.name(),
+            Self::AArch64(r) => r.name(),
+            Self::RiscV(r) => r.name(),
+        }
+    }
+
+    pub fn reg_class(self) -> InlineAsmRegClass {
+        match self {
+            Self::X86(r) => InlineAsmRegClass::X86(r.reg_class()),
+            Self::Arm(r) => InlineAsmRegClass::Arm(r.reg_class()),
+            Self::AArch64(r) => InlineAsmRegClass::AArch64(r.reg_class()),
+            Self::RiscV(r) => InlineAsmRegClass::RiscV(r.reg_class()),
+        }
+    }
+
+    pub fn parse(
+        arch: InlineAsmArch,
+        has_feature: impl FnMut(&str) -> bool,
+        name: Symbol,
+    ) -> Result<Self, &'static str> {
+        // FIXME: use direct symbol comparison for register names
+        name.with(|name| {
+            Ok(match arch {
+                InlineAsmArch::X86 | InlineAsmArch::X86_64 => {
+                    Self::X86(X86InlineAsmReg::parse(arch, has_feature, name)?)
+                }
+                InlineAsmArch::Arm => Self::Arm(ArmInlineAsmReg::parse(arch, has_feature, name)?),
+                InlineAsmArch::AArch64 => {
+                    Self::AArch64(AArch64InlineAsmReg::parse(arch, has_feature, name)?)
+                }
+                InlineAsmArch::RiscV32 | InlineAsmArch::RiscV64 => {
+                    Self::RiscV(RiscVInlineAsmReg::parse(arch, has_feature, name)?)
+                }
+            })
+        })
+    }
+
+    pub fn emit(
+        self,
+        out: &mut dyn fmt::Write,
+        arch: InlineAsmArch,
+        modifier: Option<char>,
+    ) -> fmt::Result {
+        match self {
+            Self::X86(r) => r.emit(out, arch, modifier),
+            Self::Arm(r) => r.emit(out, arch, modifier),
+            Self::AArch64(r) => r.emit(out, arch, modifier),
+            Self::RiscV(r) => r.emit(out, arch, modifier),
+        }
+    }
+
+    pub fn overlapping_regs(self, mut cb: impl FnMut(InlineAsmReg)) {
+        match self {
+            Self::X86(r) => r.overlapping_regs(|r| cb(Self::X86(r))),
+            Self::Arm(r) => r.overlapping_regs(|r| cb(Self::Arm(r))),
+            Self::AArch64(_) => cb(self),
+            Self::RiscV(_) => cb(self),
+        }
+    }
+}
+
+#[derive(
+    Copy,
+    Clone,
+    RustcEncodable,
+    RustcDecodable,
+    Debug,
+    Eq,
+    PartialEq,
+    Hash,
+    HashStable_Generic
+)]
+pub enum InlineAsmRegClass {
+    X86(X86InlineAsmRegClass),
+    Arm(ArmInlineAsmRegClass),
+    AArch64(AArch64InlineAsmRegClass),
+    RiscV(RiscVInlineAsmRegClass),
+}
+
+impl InlineAsmRegClass {
+    pub fn name(self) -> &'static str {
+        match self {
+            Self::X86(r) => r.name(),
+            Self::Arm(r) => r.name(),
+            Self::AArch64(r) => r.name(),
+            Self::RiscV(r) => r.name(),
+        }
+    }
+
+    /// Returns a suggested template modifier to use for this type and an
+    /// example of a  register named formatted with it. Optionally also returns
+    /// the name of a different register class to use instead.
+    ///
+    /// Such suggestions are useful if a type smaller than the full register
+    /// size is used and a modifier can be used to point to the subregister of
+    /// the correct size.
+    pub fn suggest_modifier(
+        self,
+        arch: InlineAsmArch,
+        ty: InlineAsmType,
+    ) -> Option<(char, &'static str, Option<&'static str>)> {
+        match self {
+            Self::X86(r) => r.suggest_modifier(arch, ty),
+            Self::Arm(r) => r.suggest_modifier(arch, ty),
+            Self::AArch64(r) => r.suggest_modifier(arch, ty),
+            Self::RiscV(r) => r.suggest_modifier(arch, ty),
+        }
+    }
+
+    /// Returns the default modifier for this register and an example of a
+    /// register named formatted with it.
+    ///
+    /// This is only needed when the register class can suggest a modifier, so
+    /// that the user can be shown how to get the default behavior without a
+    /// warning.
+    pub fn default_modifier(self, arch: InlineAsmArch) -> Option<(char, &'static str)> {
+        match self {
+            Self::X86(r) => r.default_modifier(arch),
+            Self::Arm(r) => r.default_modifier(arch),
+            Self::AArch64(r) => r.default_modifier(arch),
+            Self::RiscV(r) => r.default_modifier(arch),
+        }
+    }
+
+    /// Returns a list of supported types for this register class, each with a
+    /// options target feature required to use this type.
+    pub fn supported_types(
+        self,
+        arch: InlineAsmArch,
+    ) -> &'static [(InlineAsmType, Option<&'static str>)] {
+        match self {
+            Self::X86(r) => r.supported_types(arch),
+            Self::Arm(r) => r.supported_types(arch),
+            Self::AArch64(r) => r.supported_types(arch),
+            Self::RiscV(r) => r.supported_types(arch),
+        }
+    }
+
+    pub fn parse(arch: InlineAsmArch, name: Symbol) -> Result<Self, &'static str> {
+        // FIXME: use direct symbol comparison for register class names
+        name.with(|name| {
+            Ok(match arch {
+                InlineAsmArch::X86 | InlineAsmArch::X86_64 => {
+                    Self::X86(X86InlineAsmRegClass::parse(arch, name)?)
+                }
+                InlineAsmArch::Arm => Self::Arm(ArmInlineAsmRegClass::parse(arch, name)?),
+                InlineAsmArch::AArch64 => {
+                    Self::AArch64(AArch64InlineAsmRegClass::parse(arch, name)?)
+                }
+                InlineAsmArch::RiscV32 | InlineAsmArch::RiscV64 => {
+                    Self::RiscV(RiscVInlineAsmRegClass::parse(arch, name)?)
+                }
+            })
+        })
+    }
+
+    /// Returns the list of template modifiers that can be used with this
+    /// register class.
+    pub fn valid_modifiers(self, arch: InlineAsmArch) -> &'static [char] {
+        match self {
+            Self::X86(r) => r.valid_modifiers(arch),
+            Self::Arm(r) => r.valid_modifiers(arch),
+            Self::AArch64(r) => r.valid_modifiers(arch),
+            Self::RiscV(r) => r.valid_modifiers(arch),
+        }
+    }
+}
+
+#[derive(
+    Copy,
+    Clone,
+    RustcEncodable,
+    RustcDecodable,
+    Debug,
+    Eq,
+    PartialEq,
+    Hash,
+    HashStable_Generic
+)]
+pub enum InlineAsmRegOrRegClass {
+    Reg(InlineAsmReg),
+    RegClass(InlineAsmRegClass),
+}
+
+impl InlineAsmRegOrRegClass {
+    pub fn reg_class(self) -> InlineAsmRegClass {
+        match self {
+            Self::Reg(r) => r.reg_class(),
+            Self::RegClass(r) => r,
+        }
+    }
+}
+
+impl fmt::Display for InlineAsmRegOrRegClass {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Reg(r) => write!(f, "\"{}\"", r.name()),
+            Self::RegClass(r) => f.write_str(r.name()),
+        }
+    }
+}
+
+bitflags::bitflags! {
+    #[derive(RustcEncodable, RustcDecodable, HashStable_Generic)]
+    pub struct InlineAsmOptions: u8 {
+        const PURE = 1 << 0;
+        const NOMEM = 1 << 1;
+        const READONLY = 1 << 2;
+        const PRESERVES_FLAGS = 1 << 3;
+        const NORETURN = 1 << 4;
+        const NOSTACK = 1 << 5;
+    }
+}
+
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
+pub enum InlineAsmTemplatePiece {
+    String(String),
+    Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
+}
+
+impl fmt::Display for InlineAsmTemplatePiece {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::String(s) => {
+                for c in s.chars() {
+                    match c {
+                        '{' => f.write_str("{{")?,
+                        '}' => f.write_str("}}")?,
+                        _ => write!(f, "{}", c.escape_debug())?,
+                    }
+                }
+                Ok(())
+            }
+            Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
+                write!(f, "{{{}:{}}}", operand_idx, modifier)
+            }
+            Self::Placeholder { operand_idx, modifier: None, .. } => {
+                write!(f, "{{{}}}", operand_idx)
+            }
+        }
+    }
+}
+
+impl InlineAsmTemplatePiece {
+    /// Rebuilds the asm template string from its pieces.
+    pub fn to_string(s: &[Self]) -> String {
+        use fmt::Write;
+        let mut out = String::new();
+        for p in s.iter() {
+            let _ = write!(out, "{}", p);
+        }
+        out
+    }
+}
+
+/// Set of types which can be used with a particular register class.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum InlineAsmType {
+    I8,
+    I16,
+    I32,
+    I64,
+    I128,
+    F32,
+    F64,
+    VecI8(u64),
+    VecI16(u64),
+    VecI32(u64),
+    VecI64(u64),
+    VecI128(u64),
+    VecF32(u64),
+    VecF64(u64),
+}
+
+impl InlineAsmType {
+    pub fn is_integer(self) -> bool {
+        match self {
+            Self::I8 | Self::I16 | Self::I32 | Self::I64 | Self::I128 => true,
+            _ => false,
+        }
+    }
+
+    pub fn size(self) -> Size {
+        Size::from_bytes(match self {
+            Self::I8 => 1,
+            Self::I16 => 2,
+            Self::I32 => 4,
+            Self::I64 => 8,
+            Self::I128 => 16,
+            Self::F32 => 4,
+            Self::F64 => 8,
+            Self::VecI8(n) => n * 1,
+            Self::VecI16(n) => n * 2,
+            Self::VecI32(n) => n * 4,
+            Self::VecI64(n) => n * 8,
+            Self::VecI128(n) => n * 16,
+            Self::VecF32(n) => n * 4,
+            Self::VecF64(n) => n * 8,
+        })
+    }
+}
+
+impl fmt::Display for InlineAsmType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            Self::I8 => f.write_str("i8"),
+            Self::I16 => f.write_str("i16"),
+            Self::I32 => f.write_str("i32"),
+            Self::I64 => f.write_str("i64"),
+            Self::I128 => f.write_str("i128"),
+            Self::F32 => f.write_str("f32"),
+            Self::F64 => f.write_str("f64"),
+            Self::VecI8(n) => write!(f, "i8x{}", n),
+            Self::VecI16(n) => write!(f, "i16x{}", n),
+            Self::VecI32(n) => write!(f, "i32x{}", n),
+            Self::VecI64(n) => write!(f, "i64x{}", n),
+            Self::VecI128(n) => write!(f, "i128x{}", n),
+            Self::VecF32(n) => write!(f, "f32x{}", n),
+            Self::VecF64(n) => write!(f, "f64x{}", n),
+        }
+    }
+}
+
+/// Returns the full set of allocatable registers for a given architecture.
+///
+/// The registers are structured as a map containing the set of allocatable
+/// registers in each register class. A particular register may be allocatable
+/// from multiple register classes, in which case it will appear multiple times
+/// in the map.
+pub fn allocatable_registers(
+    arch: InlineAsmArch,
+    has_feature: impl FnMut(&str) -> bool,
+) -> FxHashMap<InlineAsmRegClass, FxHashSet<InlineAsmReg>> {
+    match arch {
+        InlineAsmArch::X86 | InlineAsmArch::X86_64 => {
+            let mut map = x86::regclass_map();
+            x86::fill_reg_map(arch, has_feature, &mut map);
+            map
+        }
+        InlineAsmArch::Arm => {
+            let mut map = arm::regclass_map();
+            arm::fill_reg_map(arch, has_feature, &mut map);
+            map
+        }
+        InlineAsmArch::AArch64 => {
+            let mut map = aarch64::regclass_map();
+            aarch64::fill_reg_map(arch, has_feature, &mut map);
+            map
+        }
+        InlineAsmArch::RiscV32 | InlineAsmArch::RiscV64 => {
+            let mut map = riscv::regclass_map();
+            riscv::fill_reg_map(arch, has_feature, &mut map);
+            map
+        }
+    }
+}

src/librustc_target/asm/riscv.rs

+use super::{InlineAsmArch, InlineAsmType};
+use rustc_macros::HashStable_Generic;
+use std::fmt;
+
+def_reg_class! {
+    RiscV RiscVInlineAsmRegClass {
+        reg,
+        freg,
+    }
+}
+
+impl RiscVInlineAsmRegClass {
+    pub fn valid_modifiers(self, _arch: super::InlineAsmArch) -> &'static [char] {
+        &[]
+    }
+
+    pub fn suggest_modifier(
+        self,
+        _arch: InlineAsmArch,
+        _ty: InlineAsmType,
+    ) -> Option<(char, &'static str, Option<&'static str>)> {
+        None
+    }
+
+    pub fn default_modifier(self, _arch: InlineAsmArch) -> Option<(char, &'static str)> {
+        None
+    }
+
+    pub fn supported_types(
+        self,
+        arch: InlineAsmArch,
+    ) -> &'static [(InlineAsmType, Option<&'static str>)] {
+        match self {
+            Self::reg => {
+                if arch == InlineAsmArch::RiscV64 {
+                    types! { _: I8, I16, I32, I64, F32, F64; }
+                } else {
+                    types! { _: I8, I16, I32, F32; }
+                }
+            }
+            Self::freg => types! { "f": F32; "d": F64; },
+        }
+    }
+}
+
+fn not_e(
+    _arch: InlineAsmArch,
+    mut has_feature: impl FnMut(&str) -> bool,
+) -> Result<(), &'static str> {
+    if has_feature("e") {
+        Err("register can't be used with the `e` target feature")
+    } else {
+        Ok(())
+    }
+}
+
+def_regs! {
+    RiscV RiscVInlineAsmReg RiscVInlineAsmRegClass {
+        x1: reg = ["x1", "ra"],
+        x5: reg = ["x5", "t0"],
+        x6: reg = ["x6", "t1"],
+        x7: reg = ["x7", "t2"],
+        x9: reg = ["x9", "s1"],
+        x10: reg = ["x10", "a0"],
+        x11: reg = ["x11", "a1"],
+        x12: reg = ["x12", "a2"],
+        x13: reg = ["x13", "a3"],
+        x14: reg = ["x14", "a4"],
+        x15: reg = ["x15", "a5"],
+        x16: reg = ["x16", "a6"] % not_e,
+        x17: reg = ["x17", "a7"] % not_e,
+        x18: reg = ["x18", "s2"] % not_e,
+        x19: reg = ["x19", "s3"] % not_e,
+        x20: reg = ["x20", "s4"] % not_e,
+        x21: reg = ["x21", "s5"] % not_e,
+        x22: reg = ["x22", "s6"] % not_e,
+        x23: reg = ["x23", "s7"] % not_e,
+        x24: reg = ["x24", "s8"] % not_e,
+        x25: reg = ["x25", "s9"] % not_e,
+        x26: reg = ["x26", "s10"] % not_e,
+        x27: reg = ["x27", "s11"] % not_e,
+        x28: reg = ["x28", "t3"] % not_e,
+        x29: reg = ["x29", "t4"] % not_e,
+        x30: reg = ["x30", "t5"] % not_e,
+        x31: reg = ["x31", "t6"] % not_e,
+        f0: freg = ["f0", "ft0"],
+        f1: freg = ["f1", "ft1"],
+        f2: freg = ["f2", "ft2"],
+        f3: freg = ["f3", "ft3"],
+        f4: freg = ["f4", "ft4"],
+        f5: freg = ["f5", "ft5"],
+        f6: freg = ["f6", "ft6"],
+        f7: freg = ["f7", "ft7"],
+        f8: freg = ["f8", "fs0"],
+        f9: freg = ["f9", "fs1"],
+        f10: freg = ["f10", "fa0"],
+        f11: freg = ["f11", "fa1"],
+        f12: freg = ["f12", "fa2"],
+        f13: freg = ["f13", "fa3"],
+        f14: freg = ["f14", "fa4"],
+        f15: freg = ["f15", "fa5"],
+        f16: freg = ["f16", "fa6"],
+        f17: freg = ["f17", "fa7"],
+        f18: freg = ["f18", "fs2"],
+        f19: freg = ["f19", "fs3"],
+        f20: freg = ["f20", "fs4"],
+        f21: freg = ["f21", "fs5"],
+        f22: freg = ["f22", "fs6"],
+        f23: freg = ["f23", "fs7"],
+        f24: freg = ["f24", "fs8"],
+        f25: freg = ["f25", "fs9"],
+        f26: freg = ["f26", "fs10"],
+        f27: freg = ["f27", "fs11"],
+        f28: freg = ["f28", "ft8"],
+        f29: freg = ["f29", "ft9"],
+        f30: freg = ["f30", "ft10"],
+        f31: freg = ["f31", "ft11"],
+        "the frame pointer cannot be used as an operand for inline asm" =
+            ["x8", "s0", "fp"],
+        "the stack pointer cannot be used as an operand for inline asm" =
+            ["x2", "sp"],
+        "the global pointer cannot be used as an operand for inline asm" =
+            ["x3", "gp"],
+        "the thread pointer cannot be used as an operand for inline asm" =
+            ["x4", "tp"],
+        "the zero register cannot be used as an operand for inline asm" =
+            ["x0", "zero"],
+    }
+}
+
+impl RiscVInlineAsmReg {
+    pub fn emit(
+        self,
+        out: &mut dyn fmt::Write,
+        _arch: InlineAsmArch,
+        _modifier: Option<char>,
+    ) -> fmt::Result {
+        out.write_str(self.name())
+    }
+}

src/librustc_target/asm/x86.rs

+use super::{InlineAsmArch, InlineAsmType};
+use rustc_macros::HashStable_Generic;
+use std::fmt;
+
+def_reg_class! {
+    X86 X86InlineAsmRegClass {
+        reg,
+        reg_abcd,
+        xmm_reg,
+        ymm_reg,
+        zmm_reg,
+        kreg,
+    }
+}
+
+impl X86InlineAsmRegClass {
+    pub fn valid_modifiers(self, arch: super::InlineAsmArch) -> &'static [char] {
+        match self {
+            Self::reg => {
+                if arch == InlineAsmArch::X86_64 {
+                    &['l', 'h', 'x', 'e', 'r']
+                } else {
+                    &['x', 'e']
+                }
+            }
+            Self::reg_abcd => {
+                if arch == InlineAsmArch::X86_64 {
+                    &['l', 'h', 'x', 'e', 'r']
+                } else {
+                    &['l', 'h', 'x', 'e']
+                }
+            }
+            Self::xmm_reg | Self::ymm_reg | Self::zmm_reg => &['x', 'y', 'z'],
+            Self::kreg => &[],
+        }
+    }
+
+    pub fn suggest_modifier(
+        self,
+        arch: InlineAsmArch,
+        ty: InlineAsmType,
+    ) -> Option<(char, &'static str, Option<&'static str>)> {
+        match self {
+            Self::reg => match ty.size().bits() {
+                8 => {
+                    if arch == InlineAsmArch::X86_64 {
+                        Some(('l', "al", None))
+                    } else {
+                        // Low byte registers require reg_abcd on x86 so we emit
+                        // a suggestion to use that register class instead.
+                        Some(('l', "al", Some("reg_abcd")))
+                    }
+                }
+                16 => Some(('x', "ax", None)),
+                32 if arch == InlineAsmArch::X86_64 => Some(('e', "eax", None)),
+                _ => None,
+            },
+            Self::reg_abcd => match ty.size().bits() {
+                8 => Some(('l', "al", None)),
+                16 => Some(('x', "ax", None)),
+                32 if arch == InlineAsmArch::X86_64 => Some(('e', "eax", None)),
+                _ => None,
+            },
+            Self::xmm_reg => None,
+            Self::ymm_reg => {
+                if ty.size().bits() <= 128 {
+                    Some(('x', "xmm0", None))
+                } else {
+                    None
+                }
+            }
+            Self::zmm_reg => match ty.size().bits() {
+                256 => Some(('y', "ymm0", None)),
+                512 => None,
+                _ => Some(('x', "xmm0", None)),
+            },
+            Self::kreg => None,
+        }
+    }
+
+    pub fn default_modifier(self, arch: InlineAsmArch) -> Option<(char, &'static str)> {
+        match self {
+            Self::reg | Self::reg_abcd => {
+                if arch == InlineAsmArch::X86_64 {
+                    Some(('r', "rax"))
+                } else {
+                    Some(('e', "eax"))
+                }
+            }
+            Self::xmm_reg => Some(('x', "xmm0")),
+            Self::ymm_reg => Some(('y', "ymm0")),
+            Self::zmm_reg => Some(('z', "zmm0")),
+            Self::kreg => None,
+        }
+    }
+
+    pub fn supported_types(
+        self,
+        arch: InlineAsmArch,
+    ) -> &'static [(InlineAsmType, Option<&'static str>)] {
+        match self {
+            Self::reg | Self::reg_abcd => {
+                if arch == InlineAsmArch::X86_64 {
+                    types! { _: I8, I16, I32, I64, F32, F64; }
+                } else {
+                    types! { _: I8, I16, I32, F32; }
+                }
+            }
+            Self::xmm_reg => types! {
+                "sse": I32, I64, F32, F64,
+                VecI8(16), VecI16(8), VecI32(4), VecI64(2), VecF32(4), VecF64(2);
+            },
+            Self::ymm_reg => types! {
+                "avx": I32, I64, F32, F64,
+                VecI8(16), VecI16(8), VecI32(4), VecI64(2), VecF32(4), VecF64(2),
+                VecI8(32), VecI16(16), VecI32(8), VecI64(4), VecF32(8), VecF64(4);
+            },
+            Self::zmm_reg => types! {
+                "avx512f": I32, I64, F32, F64,
+                VecI8(16), VecI16(8), VecI32(4), VecI64(2), VecF32(4), VecF64(2),
+                VecI8(32), VecI16(16), VecI32(8), VecI64(4), VecF32(8), VecF64(4),
+                VecI8(64), VecI16(32), VecI32(16), VecI64(8), VecF32(16), VecF64(8);
+            },
+            Self::kreg => types! {
+                "avx512f": I8, I16;
+                "avx512bw": I32, I64;
+            },
+        }
+    }
+}
+
+fn x86_64_only(
+    arch: InlineAsmArch,
+    _has_feature: impl FnMut(&str) -> bool,
+) -> Result<(), &'static str> {
+    match arch {
+        InlineAsmArch::X86 => Err("register is only available on x86_64"),
+        InlineAsmArch::X86_64 => Ok(()),
+        _ => unreachable!(),
+    }
+}
+
+def_regs! {
+    X86 X86InlineAsmReg X86InlineAsmRegClass {
+        ax: reg, reg_abcd = ["ax", "al", "eax", "rax"],
+        bx: reg, reg_abcd = ["bx", "bl", "ebx", "rbx"],
+        cx: reg, reg_abcd = ["cx", "cl", "ecx", "rcx"],
+        dx: reg, reg_abcd = ["dx", "dl", "edx", "rdx"],
+        si: reg = ["si", "sil", "esi", "rsi"],
+        di: reg = ["di", "dil", "edi", "rdi"],
+        r8: reg = ["r8", "r8b", "r8w", "r8d"] % x86_64_only,
+        r9: reg = ["r9", "r9b", "r9w", "r9d"] % x86_64_only,
+        r10: reg = ["r10", "r10b", "r10w", "r10d"] % x86_64_only,
+        r11: reg = ["r11", "r11b", "r11w", "r11d"] % x86_64_only,
+        r12: reg = ["r12", "r12b", "r12w", "r12d"] % x86_64_only,
+        r13: reg = ["r13", "r13b", "r13w", "r13d"] % x86_64_only,
+        r14: reg = ["r14", "r14b", "r14w", "r14d"] % x86_64_only,
+        r15: reg = ["r15", "r15b", "r15w", "r15d"] % x86_64_only,
+        xmm0: xmm_reg = ["xmm0"],
+        xmm1: xmm_reg = ["xmm1"],
+        xmm2: xmm_reg = ["xmm2"],
+        xmm3: xmm_reg = ["xmm3"],
+        xmm4: xmm_reg = ["xmm4"],
+        xmm5: xmm_reg = ["xmm5"],
+        xmm6: xmm_reg = ["xmm6"],
+        xmm7: xmm_reg = ["xmm7"],
+        xmm8: xmm_reg = ["xmm8"] % x86_64_only,
+        xmm9: xmm_reg = ["xmm9"] % x86_64_only,
+        xmm10: xmm_reg = ["xmm10"] % x86_64_only,
+        xmm11: xmm_reg = ["xmm11"] % x86_64_only,
+        xmm12: xmm_reg = ["xmm12"] % x86_64_only,
+        xmm13: xmm_reg = ["xmm13"] % x86_64_only,
+        xmm14: xmm_reg = ["xmm14"] % x86_64_only,
+        xmm15: xmm_reg = ["xmm15"] % x86_64_only,
+        ymm0: ymm_reg = ["ymm0"],
+        ymm1: ymm_reg = ["ymm1"],
+        ymm2: ymm_reg = ["ymm2"],
+        ymm3: ymm_reg = ["ymm3"],
+        ymm4: ymm_reg = ["ymm4"],
+        ymm5: ymm_reg = ["ymm5"],
+        ymm6: ymm_reg = ["ymm6"],
+        ymm7: ymm_reg = ["ymm7"],
+        ymm8: ymm_reg = ["ymm8"] % x86_64_only,
+        ymm9: ymm_reg = ["ymm9"] % x86_64_only,
+        ymm10: ymm_reg = ["ymm10"] % x86_64_only,
+        ymm11: ymm_reg = ["ymm11"] % x86_64_only,
+        ymm12: ymm_reg = ["ymm12"] % x86_64_only,
+        ymm13: ymm_reg = ["ymm13"] % x86_64_only,
+        ymm14: ymm_reg = ["ymm14"] % x86_64_only,
+        ymm15: ymm_reg = ["ymm15"] % x86_64_only,
+        zmm0: zmm_reg = ["zmm0"],
+        zmm1: zmm_reg = ["zmm1"],
+        zmm2: zmm_reg = ["zmm2"],
+        zmm3: zmm_reg = ["zmm3"],
+        zmm4: zmm_reg = ["zmm4"],
+        zmm5: zmm_reg = ["zmm5"],
+        zmm6: zmm_reg = ["zmm6"],
+        zmm7: zmm_reg = ["zmm7"],
+        zmm8: zmm_reg = ["zmm8"] % x86_64_only,
+        zmm9: zmm_reg = ["zmm9"] % x86_64_only,
+        zmm10: zmm_reg = ["zmm10"] % x86_64_only,
+        zmm11: zmm_reg = ["zmm11"] % x86_64_only,
+        zmm12: zmm_reg = ["zmm12"] % x86_64_only,
+        zmm13: zmm_reg = ["zmm13"] % x86_64_only,
+        zmm14: zmm_reg = ["zmm14"] % x86_64_only,
+        zmm15: zmm_reg = ["zmm15"] % x86_64_only,
+        zmm16: zmm_reg = ["zmm16", "xmm16", "ymm16"] % x86_64_only,
+        zmm17: zmm_reg = ["zmm17", "xmm17", "ymm17"] % x86_64_only,
+        zmm18: zmm_reg = ["zmm18", "xmm18", "ymm18"] % x86_64_only,
+        zmm19: zmm_reg = ["zmm19", "xmm19", "ymm19"] % x86_64_only,
+        zmm20: zmm_reg = ["zmm20", "xmm20", "ymm20"] % x86_64_only,
+        zmm21: zmm_reg = ["zmm21", "xmm21", "ymm21"] % x86_64_only,
+        zmm22: zmm_reg = ["zmm22", "xmm22", "ymm22"] % x86_64_only,
+        zmm23: zmm_reg = ["zmm23", "xmm23", "ymm23"] % x86_64_only,
+        zmm24: zmm_reg = ["zmm24", "xmm24", "ymm24"] % x86_64_only,
+        zmm25: zmm_reg = ["zmm25", "xmm25", "ymm25"] % x86_64_only,
+        zmm26: zmm_reg = ["zmm26", "xmm26", "ymm26"] % x86_64_only,
+        zmm27: zmm_reg = ["zmm27", "xmm27", "ymm27"] % x86_64_only,
+        zmm28: zmm_reg = ["zmm28", "xmm28", "ymm28"] % x86_64_only,
+        zmm29: zmm_reg = ["zmm29", "xmm29", "ymm29"] % x86_64_only,
+        zmm30: zmm_reg = ["zmm30", "xmm30", "ymm30"] % x86_64_only,
+        zmm31: zmm_reg = ["zmm31", "xmm31", "ymm31"] % x86_64_only,
+        k1: kreg = ["k1"],
+        k2: kreg = ["k2"],
+        k3: kreg = ["k3"],
+        k4: kreg = ["k4"],
+        k5: kreg = ["k5"],
+        k6: kreg = ["k6"],
+        k7: kreg = ["k7"],
+        "high byte registers are not currently supported as operands for inline asm" =
+            ["ah", "bh", "ch", "dh"],
+        "the frame pointer cannot be used as an operand for inline asm" =
+            ["bp", "bpl", "ebp", "rbp"],
+        "the stack pointer cannot be used as an operand for inline asm" =
+            ["sp", "spl", "esp", "rsp"],
+        "the instruction pointer cannot be used as an operand for inline asm" =
+            ["ip", "eip", "rip"],
+        "x87 registers are not currently supported as operands for inline asm" =
+            ["st", "st(0)", "st(1)", "st(2)", "st(3)", "st(4)", "st(5)", "st(6)", "st(7)"],
+        "MMX registers are not currently supported as operands for inline asm" =
+            ["mm0", "mm1", "mm2", "mm3", "mm4", "mm5", "mm6", "mm7"],
+        "the k0 AVX mask register cannot be used as an operand for inline asm" = ["k0"],
+    }
+}
+
+impl X86InlineAsmReg {
+    pub fn emit(
+        self,
+        out: &mut dyn fmt::Write,
+        arch: InlineAsmArch,
+        modifier: Option<char>,
+    ) -> fmt::Result {
+        let reg_default_modifier = match arch {
+            InlineAsmArch::X86 => 'e',
+            InlineAsmArch::X86_64 => 'r',
+            _ => unreachable!(),
+        };
+        if self as u32 <= Self::dx as u32 {
+            let root = ['a', 'b', 'c', 'd'][self as usize - Self::ax as usize];
+            match modifier.unwrap_or(reg_default_modifier) {
+                'l' => write!(out, "{}l", root),
+                'h' => write!(out, "{}h", root),
+                'x' => write!(out, "{}x", root),
+                'e' => write!(out, "e{}x", root),
+                'r' => write!(out, "r{}x", root),
+                _ => unreachable!(),
+            }
+        } else if self as u32 <= Self::di as u32 {
+            let root = ["si", "di"][self as usize - Self::si as usize];
+            match modifier.unwrap_or(reg_default_modifier) {
+                'l' => write!(out, "{}l", root),
+                'x' => write!(out, "{}", root),
+                'e' => write!(out, "e{}", root),
+                'r' => write!(out, "r{}", root),
+                _ => unreachable!(),
+            }
+        } else if self as u32 <= Self::r15 as u32 {
+            let index = self as u32 - Self::r8 as u32 + 8;
+            match modifier.unwrap_or(reg_default_modifier) {
+                'l' => write!(out, "r{}b", index),
+                'x' => write!(out, "r{}w", index),
+                'e' => write!(out, "r{}d", index),
+                'r' => write!(out, "r{}", index),
+                _ => unreachable!(),
+            }
+        } else if self as u32 <= Self::xmm15 as u32 {
+            let prefix = modifier.unwrap_or('x');
+            let index = self as u32 - Self::xmm0 as u32;
+            write!(out, "{}{}", prefix, index)
+        } else if self as u32 <= Self::ymm15 as u32 {
+            let prefix = modifier.unwrap_or('y');
+            let index = self as u32 - Self::ymm0 as u32;
+            write!(out, "{}{}", prefix, index)
+        } else if self as u32 <= Self::zmm31 as u32 {
+            let prefix = modifier.unwrap_or('z');
+            let index = self as u32 - Self::zmm0 as u32;
+            write!(out, "{}{}", prefix, index)
+        } else {
+            let index = self as u32 - Self::k1 as u32 + 1;
+            write!(out, "k{}", index)
+        }
+    }
+
+    pub fn overlapping_regs(self, mut cb: impl FnMut(X86InlineAsmReg)) {
+        macro_rules! reg_conflicts {
+            ($($x:ident : $y:ident : $z:ident,)*) => {
+                match self {
+                    $(
+                        Self::$x | Self::$y | Self::$z => {
+                            cb(Self::$x);
+                            cb(Self::$y);
+                            cb(Self::$z);
+                        }
+                    )*
+                    r => cb(r),
+                }
+            };
+        }
+        reg_conflicts! {
+            xmm0 : ymm0 : zmm0,
+            xmm1 : ymm1 : zmm1,
+            xmm2 : ymm2 : zmm2,
+            xmm3 : ymm3 : zmm3,
+            xmm4 : ymm4 : zmm4,
+            xmm5 : ymm5 : zmm5,
+            xmm6 : ymm6 : zmm6,
+            xmm7 : ymm7 : zmm7,
+            xmm8 : ymm8 : zmm8,
+            xmm9 : ymm9 : zmm9,
+            xmm10 : ymm10 : zmm10,
+            xmm11 : ymm11 : zmm11,
+            xmm12 : ymm12 : zmm12,
+            xmm13 : ymm13 : zmm13,
+            xmm14 : ymm14 : zmm14,
+            xmm15 : ymm15 : zmm15,
+        }
+    }
+}

src/librustc_target/lib.rs

@@ -25,9 +25,10 @@
 extern crate log;
 
 pub mod abi;
+pub mod asm;
 pub mod spec;
 
 /// Requirements for a `StableHashingContext` to be used in this crate.
 /// This is a hack to allow using the `HashStable_Generic` derive macro
 /// instead of implementing everything in librustc_middle.
-pub trait HashStableContext {}
+pub trait HashStableContext: rustc_span::HashStableContext {}