moved crates in lib/ to src/, renamed crates, modified some files' text (#660)

moved crates in lib/ to src/, renamed crates, modified some files' text (#660)

cranelift/codegen/meta/src/base/mod.rs

@@ -0,0 +1,4 @@
+//! Definitions for the base Cranelift language.
+
+pub mod settings;
+pub mod types;

cranelift/codegen/meta/src/base/settings.rs

@@ -0,0 +1,164 @@
+use crate::cdsl::settings::{SettingGroup, SettingGroupBuilder};
+
+pub fn generate() -> SettingGroup {
+    let mut settings = SettingGroupBuilder::new("shared");
+
+    settings.add_enum(
+        "opt_level",
+        r#"
+        Optimization level:
+
+        - default: Very profitable optimizations enabled, none slow.
+        - best: Enable all optimizations
+        - fastest: Optimize for compile time by disabling most optimizations.
+        "#,
+        vec!["default", "best", "fastest"],
+    );
+
+    settings.add_bool(
+        "enable_verifier",
+        r#"
+        Run the Cranelift IR verifier at strategic times during compilation.
+
+        This makes compilation slower but catches many bugs. The verifier is
+        disabled by default, except when reading Cranelift IR from a text file.
+        "#,
+        true,
+    );
+
+    // Note that Cranelift doesn't currently need an is_pie flag, because PIE is
+    // just PIC where symbols can't be pre-empted, which can be expressed with the
+    // `colocated` flag on external functions and global values.
+    settings.add_bool(
+        "is_pic",
+        "Enable Position-Independent Code generation",
+        false,
+    );
+
+    settings.add_bool(
+        "colocated_libcalls",
+        r#"
+            Use colocated libcalls.
+
+            Generate code that assumes that libcalls can be declared "colocated",
+            meaning they will be defined along with the current function, such that
+            they can use more efficient addressing.
+            "#,
+        false,
+    );
+
+    settings.add_bool(
+        "avoid_div_traps",
+        r#"
+            Generate explicit checks around native division instructions to avoid
+            their trapping.
+
+            This is primarily used by SpiderMonkey which doesn't install a signal
+            handler for SIGFPE, but expects a SIGILL trap for division by zero.
+
+            On ISAs like ARM where the native division instructions don't trap,
+            this setting has no effect - explicit checks are always inserted.
+            "#,
+        false,
+    );
+
+    settings.add_bool(
+        "enable_float",
+        r#"
+            Enable the use of floating-point instructions
+
+            Disabling use of floating-point instructions is not yet implemented.
+            "#,
+        true,
+    );
+
+    settings.add_bool(
+        "enable_nan_canonicalization",
+        r#"
+            Enable NaN canonicalization
+
+            This replaces NaNs with a single canonical value, for users requiring
+            entirely deterministic WebAssembly computation. This is not required
+            by the WebAssembly spec, so it is not enabled by default.
+            "#,
+        false,
+    );
+
+    settings.add_bool("enable_simd", "Enable the use of SIMD instructions.", true);
+
+    settings.add_bool(
+        "enable_atomics",
+        "Enable the use of atomic instructions",
+        true,
+    );
+
+    // Settings specific to the `baldrdash` calling convention.
+
+    settings.add_num(
+        "baldrdash_prologue_words",
+        r#"
+            Number of pointer-sized words pushed by the baldrdash prologue.
+
+            Functions with the `baldrdash` calling convention don't generate their
+            own prologue and epilogue. They depend on externally generated code
+            that pushes a fixed number of words in the prologue and restores them
+            in the epilogue.
+
+            This setting configures the number of pointer-sized words pushed on the
+            stack when the Cranelift-generated code is entered. This includes the
+            pushed return address on x86.
+            "#,
+        0,
+    );
+
+    // BaldrMonkey requires that not-yet-relocated function addresses be encoded
+    // as all-ones bitpatterns.
+    settings.add_bool(
+        "allones_funcaddrs",
+        "Emit not-yet-relocated function addresses as all-ones bit patterns.",
+        false,
+    );
+
+    // Stack probing options.
+
+    settings.add_bool(
+        "probestack_enabled",
+        r#"
+            Enable the use of stack probes, for calling conventions which support this
+            functionality.
+            "#,
+        true,
+    );
+
+    settings.add_bool(
+        "probestack_func_adjusts_sp",
+        r#"
+            Set this to true of the stack probe function modifies the stack pointer
+            itself.
+            "#,
+        false,
+    );
+
+    settings.add_num(
+        "probestack_size_log2",
+        r#"
+            The log2 of the size of the stack guard region.
+
+            Stack frames larger than this size will have stack overflow checked
+            by calling the probestack function.
+
+            The default is 12, which translates to a size of 4096.
+            "#,
+        12,
+    );
+
+    // Jump table options.
+
+    settings.add_bool(
+        "jump_tables_enabled",
+        "Enable the use of jump tables in generated machine code.",
+        true,
+    );
+
+    settings.finish()
+}

cranelift/codegen/meta/src/base/types.rs

@@ -0,0 +1,188 @@
+//! This module predefines all the Cranelift scalar types.
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum Bool {
+    /// 1-bit bool.
+    B1 = 1,
+    /// 8-bit bool.
+    B8 = 8,
+    /// 16-bit bool.
+    B16 = 16,
+    /// 32-bit bool.
+    B32 = 32,
+    /// 64-bit bool.
+    B64 = 64,
+}
+
+/// This provides an iterator through all of the supported bool variants.
+pub struct BoolIterator {
+    index: u8,
+}
+
+impl BoolIterator {
+    pub fn new() -> Self {
+        Self { index: 0 }
+    }
+}
+
+impl Iterator for BoolIterator {
+    type Item = Bool;
+    fn next(&mut self) -> Option<Self::Item> {
+        let res = match self.index {
+            0 => Some(Bool::B1),
+            1 => Some(Bool::B8),
+            2 => Some(Bool::B16),
+            3 => Some(Bool::B32),
+            4 => Some(Bool::B64),
+            _ => return None,
+        };
+        self.index += 1;
+        res
+    }
+}
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum Int {
+    /// 8-bit int.
+    I8 = 8,
+    /// 16-bit int.
+    I16 = 16,
+    /// 32-bit int.
+    I32 = 32,
+    /// 64-bit int.
+    I64 = 64,
+}
+
+/// This provides an iterator through all of the supported int variants.
+pub struct IntIterator {
+    index: u8,
+}
+
+impl IntIterator {
+    pub fn new() -> Self {
+        Self { index: 0 }
+    }
+}
+
+impl Iterator for IntIterator {
+    type Item = Int;
+    fn next(&mut self) -> Option<Self::Item> {
+        let res = match self.index {
+            0 => Some(Int::I8),
+            1 => Some(Int::I16),
+            2 => Some(Int::I32),
+            3 => Some(Int::I64),
+            _ => return None,
+        };
+        self.index += 1;
+        res
+    }
+}
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum Float {
+    F32 = 32,
+    F64 = 64,
+}
+
+/// Iterator through the variants of the Float enum.
+pub struct FloatIterator {
+    index: u8,
+}
+
+impl FloatIterator {
+    pub fn new() -> Self {
+        Self { index: 0 }
+    }
+}
+
+/// This provides an iterator through all of the supported float variants.
+impl Iterator for FloatIterator {
+    type Item = Float;
+    fn next(&mut self) -> Option<Self::Item> {
+        let res = match self.index {
+            0 => Some(Float::F32),
+            1 => Some(Float::F64),
+            _ => return None,
+        };
+        self.index += 1;
+        res
+    }
+}
+
+/// A type representing CPU flags.
+///
+/// Flags can't be stored in memory.
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum Flag {
+    /// CPU flags from an integer comparison.
+    IFlags,
+    /// CPU flags from a floating point comparison.
+    FFlags,
+}
+
+/// Iterator through the variants of the Flag enum.
+pub struct FlagIterator {
+    index: u8,
+}
+
+impl FlagIterator {
+    pub fn new() -> Self {
+        Self { index: 0 }
+    }
+}
+
+impl Iterator for FlagIterator {
+    type Item = Flag;
+    fn next(&mut self) -> Option<Self::Item> {
+        let res = match self.index {
+            0 => Some(Flag::IFlags),
+            1 => Some(Flag::FFlags),
+            _ => return None,
+        };
+        self.index += 1;
+        res
+    }
+}
+
+#[cfg(test)]
+mod iter_tests {
+    use super::*;
+
+    #[test]
+    fn bool_iter_works() {
+        let mut bool_iter = BoolIterator::new();
+        assert_eq!(bool_iter.next(), Some(Bool::B1));
+        assert_eq!(bool_iter.next(), Some(Bool::B8));
+        assert_eq!(bool_iter.next(), Some(Bool::B16));
+        assert_eq!(bool_iter.next(), Some(Bool::B32));
+        assert_eq!(bool_iter.next(), Some(Bool::B64));
+        assert_eq!(bool_iter.next(), None);
+    }
+
+    #[test]
+    fn int_iter_works() {
+        let mut int_iter = IntIterator::new();
+        assert_eq!(int_iter.next(), Some(Int::I8));
+        assert_eq!(int_iter.next(), Some(Int::I16));
+        assert_eq!(int_iter.next(), Some(Int::I32));
+        assert_eq!(int_iter.next(), Some(Int::I64));
+        assert_eq!(int_iter.next(), None);
+    }
+
+    #[test]
+    fn float_iter_works() {
+        let mut float_iter = FloatIterator::new();
+        assert_eq!(float_iter.next(), Some(Float::F32));
+        assert_eq!(float_iter.next(), Some(Float::F64));
+        assert_eq!(float_iter.next(), None);
+    }
+
+    #[test]
+    fn flag_iter_works() {
+        let mut flag_iter = FlagIterator::new();
+        assert_eq!(flag_iter.next(), Some(Flag::IFlags));
+        assert_eq!(flag_iter.next(), Some(Flag::FFlags));
+        assert_eq!(flag_iter.next(), None);
+    }
+}

cranelift/codegen/meta/src/cdsl/isa.rs

@@ -0,0 +1,192 @@
+use cranelift_entity::PrimaryMap;
+
+use super::regs::{
+    RegBank, RegBankBuilder, RegBankIndex, RegClass, RegClassBuilder, RegClassIndex, RegClassProto,
+};
+use super::settings::SettingGroup;
+
+pub struct TargetIsa {
+    pub name: &'static str,
+    pub reg_banks: PrimaryMap<RegBankIndex, RegBank>,
+    pub reg_classes: PrimaryMap<RegClassIndex, RegClass>,
+    pub settings: SettingGroup,
+}
+
+impl TargetIsa {
+    pub fn new(name: &'static str, settings: SettingGroup) -> Self {
+        Self {
+            name,
+            reg_banks: PrimaryMap::new(),
+            reg_classes: PrimaryMap::new(),
+            settings,
+        }
+    }
+}
+
+pub struct TargetIsaBuilder {
+    isa: TargetIsa,
+}
+
+impl TargetIsaBuilder {
+    pub fn new(name: &'static str, settings: SettingGroup) -> Self {
+        Self {
+            isa: TargetIsa::new(name, settings),
+        }
+    }
+
+    pub fn add_reg_bank(&mut self, builder: RegBankBuilder) -> RegBankIndex {
+        let first_unit = if self.isa.reg_banks.len() == 0 {
+            0
+        } else {
+            let last = &self.isa.reg_banks.last().unwrap();
+            let first_available_unit = (last.first_unit + last.units) as i8;
+            let units = builder.units;
+            let align = if units.is_power_of_two() {
+                units
+            } else {
+                units.next_power_of_two()
+            } as i8;
+            (first_available_unit + align - 1) & -align
+        } as u8;
+
+        self.isa.reg_banks.push(RegBank::new(
+            builder.name,
+            first_unit,
+            builder.units,
+            builder.names,
+            builder.prefix,
+            builder
+                .pressure_tracking
+                .expect("Pressure tracking must be explicitly set"),
+        ))
+    }
+
+    pub fn add_reg_class(&mut self, builder: RegClassBuilder) -> RegClassIndex {
+        let class_index = self.isa.reg_classes.next_key();
+
+        // Finish delayed construction of RegClass.
+        let (bank, toprc, start, width) = match builder.proto {
+            RegClassProto::TopLevel(bank_index) => {
+                self.isa
+                    .reg_banks
+                    .get_mut(bank_index)
+                    .unwrap()
+                    .toprcs
+                    .push(class_index);
+                (bank_index, class_index, builder.start, builder.width)
+            }
+            RegClassProto::SubClass(parent_class_index) => {
+                assert!(builder.width == 0);
+                let (bank, toprc, start, width) = {
+                    let parent = self.isa.reg_classes.get(parent_class_index).unwrap();
+                    (parent.bank, parent.toprc, parent.start, parent.width)
+                };
+                for reg_class in self.isa.reg_classes.values_mut() {
+                    if reg_class.toprc == toprc {
+                        reg_class.subclasses.push(class_index);
+                    }
+                }
+                let subclass_start = start + builder.start * width;
+                (bank, toprc, subclass_start, width)
+            }
+        };
+
+        let reg_bank_units = self.isa.reg_banks.get(bank).unwrap().units;
+        assert!(start < reg_bank_units);
+
+        let count = if builder.count != 0 {
+            builder.count
+        } else {
+            reg_bank_units / width
+        };
+
+        let reg_class = RegClass::new(builder.name, class_index, width, bank, toprc, count, start);
+        self.isa.reg_classes.push(reg_class);
+
+        let reg_bank = self.isa.reg_banks.get_mut(bank).unwrap();
+        reg_bank.classes.push(class_index);
+
+        class_index
+    }
+
+    /// Checks that the set of register classes satisfies:
+    ///
+    /// 1. Closed under intersection: The intersection of any two register
+    ///    classes in the set is either empty or identical to a member of the
+    ///    set.
+    /// 2. There are no identical classes under different names.
+    /// 3. Classes are sorted topologically such that all subclasses have a
+    ///    higher index that the superclass.
+    pub fn finish(self) -> TargetIsa {
+        for reg_bank in self.isa.reg_banks.values() {
+            for i1 in reg_bank.classes.iter() {
+                for i2 in reg_bank.classes.iter() {
+                    if i1 >= i2 {
+                        continue;
+                    }
+
+                    let rc1 = self.isa.reg_classes.get(*i1).unwrap();
+                    let rc2 = self.isa.reg_classes.get(*i2).unwrap();
+
+                    let rc1_mask = rc1.mask(0);
+                    let rc2_mask = rc2.mask(0);
+
+                    assert!(
+                        rc1.width != rc2.width || rc1_mask != rc2_mask,
+                        "no duplicates"
+                    );
+                    if rc1.width != rc2.width {
+                        continue;
+                    }
+
+                    let mut intersect = Vec::new();
+                    for (a, b) in rc1_mask.iter().zip(rc2_mask.iter()) {
+                        intersect.push(a & b);
+                    }
+                    if intersect == vec![0; intersect.len()] {
+                        continue;
+                    }
+
+                    // Classes must be topologically ordered, so the intersection can't be the
+                    // superclass.
+                    assert!(intersect != rc1_mask);
+
+                    // If the intersection is the second one, then it must be a subclass.
+                    if intersect == rc2_mask {
+                        assert!(self
+                            .isa
+                            .reg_classes
+                            .get(*i1)
+                            .unwrap()
+                            .subclasses
+                            .iter()
+                            .find(|x| **x == *i2)
+                            .is_some());
+                    }
+                }
+            }
+        }
+
+        // This limit should be coordinated with the `RegClassMask` and `RegClassIndex` types in
+        // isa/registers.rs of the non-meta code.
+        assert!(
+            self.isa.reg_classes.len() <= 32,
+            "Too many register classes"
+        );
+
+        // The maximum number of top-level register classes which have pressure tracking should be
+        // kept in sync with the MAX_TRACKED_TOPRCS constant in isa/registers.rs of the non-meta
+        // code.
+        let num_toplevel = self
+            .isa
+            .reg_classes
+            .values()
+            .filter(|x| {
+                x.toprc == x.index && self.isa.reg_banks.get(x.bank).unwrap().pressure_tracking
+            })
+            .count();
+        assert!(num_toplevel <= 4, "Too many top-level register classes");
+
+        self.isa
+    }
+}

cranelift/codegen/meta/src/cdsl/mod.rs

@@ -0,0 +1,68 @@
+//! Cranelift DSL classes.
+//!
+//! This module defines the classes that are used to define Cranelift
+//! instructions and other entities.
+
+pub mod isa;
+pub mod regs;
+pub mod settings;
+pub mod types;
+
+/// A macro that converts boolean settings into predicates to look more natural.
+#[macro_export]
+macro_rules! predicate {
+    ($a:ident && $($b:tt)*) => {
+        PredicateNode::And(Box::new($a.into()), Box::new(predicate!($($b)*)))
+    };
+    ($a:ident) => {
+        $a.into()
+    };
+}
+
+#[macro_export]
+macro_rules! preset {
+    () => {
+        vec![]
+    };
+    ($($x:ident)&&*) => {
+        {
+            let mut v = Vec::new();
+            $(
+                v.push($x.into());
+            )*
+            v
+        }
+    };
+}
+
+/// Convert the string `s` to CamelCase.
+pub fn camel_case(s: &str) -> String {
+    let mut output_chars = String::with_capacity(s.len());
+
+    let mut capitalize = true;
+    for curr_char in s.chars() {
+        if curr_char == '_' {
+            capitalize = true;
+        } else {
+            if capitalize {
+                output_chars.extend(curr_char.to_uppercase());
+            } else {
+                output_chars.push(curr_char);
+            }
+            capitalize = false;
+        }
+    }
+
+    output_chars
+}
+
+#[cfg(test)]
+mod tests {
+    use super::camel_case;
+
+    #[test]
+    fn camel_case_works() {
+        assert_eq!(camel_case("x"), "X");
+        assert_eq!(camel_case("camel_case"), "CamelCase");
+    }
+}

cranelift/codegen/meta/src/cdsl/regs.rs

@@ -0,0 +1,180 @@
+use cranelift_entity::entity_impl;
+use cranelift_entity::EntityRef;
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct RegBankIndex(u32);
+entity_impl!(RegBankIndex);
+
+pub struct RegBank {
+    pub name: &'static str,
+    pub first_unit: u8,
+    pub units: u8,
+    pub names: Vec<&'static str>,
+    pub prefix: &'static str,
+    pub pressure_tracking: bool,
+    pub toprcs: Vec<RegClassIndex>,
+    pub classes: Vec<RegClassIndex>,
+}
+
+impl RegBank {
+    pub fn new(
+        name: &'static str,
+        first_unit: u8,
+        units: u8,
+        names: Vec<&'static str>,
+        prefix: &'static str,
+        pressure_tracking: bool,
+    ) -> Self {
+        RegBank {
+            name,
+            first_unit,
+            units,
+            names,
+            prefix,
+            pressure_tracking,
+            toprcs: Vec::new(),
+            classes: Vec::new(),
+        }
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct RegClassIndex(u32);
+entity_impl!(RegClassIndex);
+
+pub struct RegClass {
+    pub name: &'static str,
+    pub index: RegClassIndex,
+    pub width: u8,
+    pub bank: RegBankIndex,
+    pub toprc: RegClassIndex,
+    pub count: u8,
+    pub start: u8,
+    pub subclasses: Vec<RegClassIndex>,
+}
+
+impl RegClass {
+    pub fn new(
+        name: &'static str,
+        index: RegClassIndex,
+        width: u8,
+        bank: RegBankIndex,
+        toprc: RegClassIndex,
+        count: u8,
+        start: u8,
+    ) -> Self {
+        Self {
+            name,
+            index,
+            width,
+            bank,
+            toprc,
+            count,
+            start,
+            subclasses: Vec::new(),
+        }
+    }
+
+    /// Compute a bit-mask of subclasses, including self.
+    pub fn subclass_mask(&self) -> u64 {
+        let mut m = 1 << self.index.index();
+        for rc in self.subclasses.iter() {
+            m |= 1 << rc.index();
+        }
+        m
+    }
+
+    /// Compute a bit-mask of the register units allocated by this register class.
+    pub fn mask(&self, bank_first_unit: u8) -> Vec<u32> {
+        let mut u = (self.start + bank_first_unit) as usize;
+        let mut out_mask = vec![0, 0, 0];
+        for _ in 0..self.count {
+            out_mask[u / 32] |= 1 << (u % 32);
+            u += self.width as usize;
+        }
+        out_mask
+    }
+}
+
+pub enum RegClassProto {
+    TopLevel(RegBankIndex),
+    SubClass(RegClassIndex),
+}
+
+pub struct RegClassBuilder {
+    pub name: &'static str,
+    pub width: u8,
+    pub count: u8,
+    pub start: u8,
+    pub proto: RegClassProto,
+}
+
+impl RegClassBuilder {
+    pub fn new_toplevel(name: &'static str, bank: RegBankIndex) -> Self {
+        Self {
+            name,
+            width: 1,
+            count: 0,
+            start: 0,
+            proto: RegClassProto::TopLevel(bank),
+        }
+    }
+    pub fn subclass_of(
+        name: &'static str,
+        parent_index: RegClassIndex,
+        start: u8,
+        stop: u8,
+    ) -> Self {
+        assert!(stop >= start);
+        Self {
+            name,
+            width: 0,
+            count: stop - start,
+            start: start,
+            proto: RegClassProto::SubClass(parent_index),
+        }
+    }
+    pub fn count(mut self, count: u8) -> Self {
+        self.count = count;
+        self
+    }
+    pub fn width(mut self, width: u8) -> Self {
+        match self.proto {
+            RegClassProto::TopLevel(_) => self.width = width,
+            RegClassProto::SubClass(_) => panic!("Subclasses inherit their parent's width."),
+        }
+        self
+    }
+}
+
+pub struct RegBankBuilder {
+    pub name: &'static str,
+    pub units: u8,
+    pub names: Vec<&'static str>,
+    pub prefix: &'static str,
+    pub pressure_tracking: Option<bool>,
+}
+
+impl RegBankBuilder {
+    pub fn new(name: &'static str, prefix: &'static str) -> Self {
+        Self {
+            name,
+            units: 0,
+            names: vec![],
+            prefix,
+            pressure_tracking: None,
+        }
+    }
+    pub fn units(mut self, units: u8) -> Self {
+        self.units = units;
+        self
+    }
+    pub fn names(mut self, names: Vec<&'static str>) -> Self {
+        self.names = names;
+        self
+    }
+    pub fn track_pressure(mut self, track: bool) -> Self {
+        self.pressure_tracking = Some(track);
+        self
+    }
+}

cranelift/codegen/meta/src/cdsl/settings.rs

@@ -0,0 +1,387 @@
+use std::iter;
+
+#[derive(Clone, Copy, Hash, PartialEq, Eq)]
+pub struct BoolSettingIndex(usize);
+
+#[derive(Hash, PartialEq, Eq)]
+pub struct BoolSetting {
+    pub default: bool,
+    pub bit_offset: u8,
+    pub predicate_number: u8,
+}
+
+#[derive(Hash, PartialEq, Eq)]
+pub enum SpecificSetting {
+    Bool(BoolSetting),
+    Enum(Vec<&'static str>),
+    Num(u8),
+}
+
+#[derive(Hash, PartialEq, Eq)]
+pub struct Setting {
+    pub name: &'static str,
+    pub comment: &'static str,
+    pub specific: SpecificSetting,
+    pub byte_offset: u8,
+}
+
+impl Setting {
+    pub fn default_byte(&self) -> u8 {
+        match self.specific {
+            SpecificSetting::Bool(BoolSetting {
+                default,
+                bit_offset,
+                ..
+            }) => {
+                if default {
+                    1 << bit_offset
+                } else {
+                    0
+                }
+            }
+            SpecificSetting::Enum(_) => 0,
+            SpecificSetting::Num(default) => default,
+        }
+    }
+
+    fn byte_for_value(&self, v: bool) -> u8 {
+        match self.specific {
+            SpecificSetting::Bool(BoolSetting { bit_offset, .. }) => {
+                if v {
+                    1 << bit_offset
+                } else {
+                    0
+                }
+            }
+            _ => panic!("byte_for_value shouldn't be used for non-boolean settings."),
+        }
+    }
+
+    fn byte_mask(&self) -> u8 {
+        match self.specific {
+            SpecificSetting::Bool(BoolSetting { bit_offset, .. }) => 1 << bit_offset,
+            _ => panic!("byte_for_value shouldn't be used for non-boolean settings."),
+        }
+    }
+}
+
+#[derive(Hash, PartialEq, Eq)]
+pub struct PresetIndex(usize);
+
+#[derive(Hash, PartialEq, Eq)]
+pub enum PresetType {
+    BoolSetting(BoolSettingIndex),
+    OtherPreset(PresetIndex),
+}
+
+impl Into<PresetType> for BoolSettingIndex {
+    fn into(self) -> PresetType {
+        PresetType::BoolSetting(self)
+    }
+}
+impl Into<PresetType> for PresetIndex {
+    fn into(self) -> PresetType {
+        PresetType::OtherPreset(self)
+    }
+}
+
+#[derive(Hash, PartialEq, Eq)]
+pub struct Preset {
+    pub name: &'static str,
+    values: Vec<BoolSettingIndex>,
+}
+
+impl Preset {
+    pub fn layout(&self, group: &SettingGroup) -> Vec<(u8, u8)> {
+        let mut layout: Vec<(u8, u8)> = iter::repeat((0, 0))
+            .take(group.settings_size as usize)
+            .collect();
+        for bool_index in &self.values {
+            let setting = &group.settings[bool_index.0];
+            let mask = setting.byte_mask();
+            let val = setting.byte_for_value(true);
+            assert!((val & !mask) == 0);
+            let (ref mut l_mask, ref mut l_val) =
+                *layout.get_mut(setting.byte_offset as usize).unwrap();
+            *l_mask |= mask;
+            *l_val = (*l_val & !mask) | val;
+        }
+        layout
+    }
+}
+
+pub struct SettingGroup {
+    pub name: &'static str,
+    pub settings: Vec<Setting>,
+    pub bool_start_byte_offset: u8,
+    pub settings_size: u8,
+    pub presets: Vec<Preset>,
+    pub predicates: Vec<Predicate>,
+}
+
+impl SettingGroup {
+    fn num_bool_settings(&self) -> u8 {
+        self.settings
+            .iter()
+            .filter(|s| {
+                if let SpecificSetting::Bool(_) = s.specific {
+                    true
+                } else {
+                    false
+                }
+            })
+            .count() as u8
+    }
+
+    pub fn byte_size(&self) -> u8 {
+        let num_predicates = self.num_bool_settings() + (self.predicates.len() as u8);
+        self.bool_start_byte_offset + (num_predicates + 7) / 8
+    }
+
+    pub fn get_bool(&self, name: &'static str) -> (BoolSettingIndex, &Self) {
+        for (i, s) in self.settings.iter().enumerate() {
+            if let SpecificSetting::Bool(_) = s.specific {
+                if s.name == name {
+                    return (BoolSettingIndex(i), self);
+                }
+            }
+        }
+        panic!("Should have found bool setting by name.");
+    }
+}
+
+/// This is the basic information needed to track the specific parts of a setting when building
+/// them.
+pub enum ProtoSpecificSetting {
+    Bool(bool, u8),
+    Enum(Vec<&'static str>),
+    Num(u8),
+}
+
+/// This is the information provided during building for a setting.
+struct ProtoSetting {
+    name: &'static str,
+    comment: &'static str,
+    specific: ProtoSpecificSetting,
+}
+
+#[derive(Hash, PartialEq, Eq)]
+pub enum PredicateNode {
+    OwnedBool(BoolSettingIndex),
+    SharedBool(&'static str, &'static str),
+    And(Box<PredicateNode>, Box<PredicateNode>),
+}
+
+impl Into<PredicateNode> for BoolSettingIndex {
+    fn into(self) -> PredicateNode {
+        PredicateNode::OwnedBool(self)
+    }
+}
+impl<'a> Into<PredicateNode> for (BoolSettingIndex, &'a SettingGroup) {
+    fn into(self) -> PredicateNode {
+        let (index, group) = (self.0, self.1);
+        let setting = &group.settings[index.0];
+        PredicateNode::SharedBool(group.name, setting.name)
+    }
+}
+
+impl PredicateNode {
+    fn render(&self, group: &SettingGroup) -> String {
+        match *self {
+            PredicateNode::OwnedBool(bool_setting_index) => format!(
+                "{}.{}()",
+                group.name, group.settings[bool_setting_index.0].name
+            ),
+            PredicateNode::SharedBool(ref group_name, ref bool_name) => {
+                format!("{}.{}()", group_name, bool_name)
+            }
+            PredicateNode::And(ref lhs, ref rhs) => {
+                format!("{} && {}", lhs.render(group), rhs.render(group))
+            }
+        }
+    }
+}
+
+pub struct Predicate {
+    pub name: &'static str,
+    node: PredicateNode,
+    pub number: u8,
+}
+
+impl Predicate {
+    pub fn render(&self, group: &SettingGroup) -> String {
+        self.node.render(group)
+    }
+}
+
+pub struct SettingGroupBuilder {
+    name: &'static str,
+    settings: Vec<ProtoSetting>,
+    presets: Vec<Preset>,
+    predicates: Vec<Predicate>,
+    predicate_number: u8,
+}
+
+impl SettingGroupBuilder {
+    pub fn new(name: &'static str) -> Self {
+        Self {
+            name,
+            settings: Vec::new(),
+            presets: Vec::new(),
+            predicates: Vec::new(),
+            predicate_number: 0,
+        }
+    }
+
+    fn add_setting(
+        &mut self,
+        name: &'static str,
+        comment: &'static str,
+        specific: ProtoSpecificSetting,
+    ) {
+        self.settings.push(ProtoSetting {
+            name,
+            comment,
+            specific,
+        })
+    }
+
+    pub fn add_bool(
+        &mut self,
+        name: &'static str,
+        comment: &'static str,
+        default: bool,
+    ) -> BoolSettingIndex {
+        assert!(
+            self.predicates.len() == 0,
+            "predicates must be added after the boolean settings"
+        );
+        let predicate_number = self.predicate_number;
+        self.predicate_number += 1;
+        self.add_setting(
+            name,
+            comment,
+            ProtoSpecificSetting::Bool(default, predicate_number),
+        );
+        BoolSettingIndex(self.settings.len() - 1)
+    }
+
+    pub fn add_enum(
+        &mut self,
+        name: &'static str,
+        comment: &'static str,
+        values: Vec<&'static str>,
+    ) {
+        self.add_setting(name, comment, ProtoSpecificSetting::Enum(values));
+    }
+
+    pub fn add_num(&mut self, name: &'static str, comment: &'static str, default: u8) {
+        self.add_setting(name, comment, ProtoSpecificSetting::Num(default));
+    }
+
+    pub fn add_predicate(&mut self, name: &'static str, node: PredicateNode) {
+        let number = self.predicate_number;
+        self.predicate_number += 1;
+        self.predicates.push(Predicate { name, node, number });
+    }
+
+    pub fn add_preset(&mut self, name: &'static str, args: Vec<PresetType>) -> PresetIndex {
+        let mut values = Vec::new();
+        for arg in args {
+            match arg {
+                PresetType::OtherPreset(index) => {
+                    values.extend(self.presets[index.0].values.iter());
+                }
+                PresetType::BoolSetting(index) => values.push(index),
+            }
+        }
+        self.presets.push(Preset { name, values });
+        PresetIndex(self.presets.len() - 1)
+    }
+
+    /// Compute the layout of the byte vector used to represent this settings
+    /// group.
+    ///
+    /// The byte vector contains the following entries in order:
+    ///
+    /// 1. Byte-sized settings like `NumSetting` and `EnumSetting`.
+    /// 2. `BoolSetting` settings.
+    /// 3. Precomputed named predicates.
+    /// 4. Other numbered predicates, including anonymous predicates and parent
+    ///    predicates that need to be accessible by number.
+    ///
+    /// Set `self.settings_size` to the length of the byte vector prefix that
+    /// contains the settings. All bytes after that are computed, not
+    /// configured.
+    ///
+    /// Set `self.boolean_offset` to the beginning of the numbered predicates,
+    /// 2. in the list above.
+    ///
+    /// Assign `byte_offset` and `bit_offset` fields in all settings.
+    ///
+    /// After calling this method, no more settings can be added, but
+    /// additional predicates can be made accessible with `number_predicate()`.
+    pub fn finish(self) -> SettingGroup {
+        let mut group = SettingGroup {
+            name: self.name,
+            settings: Vec::new(),
+            bool_start_byte_offset: 0,
+            settings_size: 0,
+            presets: Vec::new(),
+            predicates: Vec::new(),
+        };
+
+        let mut byte_offset = 0;
+
+        // Assign the non-boolean settings first.
+        for s in &self.settings {
+            let specific = match s.specific {
+                ProtoSpecificSetting::Bool(..) => continue,
+                ProtoSpecificSetting::Enum(ref values) => SpecificSetting::Enum(values.clone()),
+                ProtoSpecificSetting::Num(default) => SpecificSetting::Num(default),
+            };
+
+            group.settings.push(Setting {
+                name: s.name,
+                comment: s.comment,
+                byte_offset,
+                specific,
+            });
+
+            byte_offset += 1;
+        }
+
+        group.bool_start_byte_offset = byte_offset;
+
+        // Then the boolean settings.
+        for s in &self.settings {
+            let (default, predicate_number) = match s.specific {
+                ProtoSpecificSetting::Bool(default, predicate_number) => {
+                    (default, predicate_number)
+                }
+                ProtoSpecificSetting::Enum(_) | ProtoSpecificSetting::Num(_) => continue,
+            };
+            group.settings.push(Setting {
+                name: s.name,
+                comment: s.comment,
+                byte_offset: byte_offset + predicate_number / 8,
+                specific: SpecificSetting::Bool(BoolSetting {
+                    default,
+                    bit_offset: predicate_number % 8,
+                    predicate_number,
+                }),
+            });
+        }
+
+        assert!(
+            group.predicates.len() == 0,
+            "settings_size is the byte size before adding predicates"
+        );
+        group.settings_size = group.byte_size();
+
+        group.predicates.extend(self.predicates);
+        group.presets.extend(self.presets);
+
+        group
+    }
+}

cranelift/codegen/meta/src/cdsl/types.rs

@@ -0,0 +1,473 @@
+//! Cranelift ValueType hierarchy
+
+// Temporary disabled: Unused at the moment.
+// use std::collections::HashMap;
+
+use std::fmt;
+
+use crate::base::types as base_types;
+
+// Numbering scheme for value types:
+//
+// 0: Void
+// 0x01-0x6f: Special types
+// 0x70-0x7f: Lane types
+// 0x80-0xff: Vector types
+//
+// Vector types are encoded with the lane type in the low 4 bits and log2(lanes)
+// in the high 4 bits, giving a range of 2-256 lanes.
+static LANE_BASE: u8 = 0x70;
+
+// Rust name prefix used for the `rust_name` method.
+static _RUST_NAME_PREFIX: &'static str = "ir::types::";
+
+// ValueType variants (i8, i32, ...) are provided in `base::types.rs`.
+
+/// A concrete SSA value type.
+///
+/// All SSA values have a type that is described by an instance of `ValueType`
+/// or one of its subclasses.
+#[derive(Debug)]
+pub enum ValueType {
+    BV(BVType),
+    Lane(LaneType),
+    Special(SpecialType),
+    Vector(VectorType),
+}
+
+impl ValueType {
+    /// Iterate through all of the lane types.
+    pub fn all_lane_types() -> LaneTypeIterator {
+        LaneTypeIterator::new()
+    }
+
+    /// Iterate through all of the special types (neither lanes nor vectors).
+    pub fn all_special_types() -> SpecialTypeIterator {
+        SpecialTypeIterator::new()
+    }
+
+    /// Return a string containing the documentation comment for this type.
+    pub fn doc(&self) -> String {
+        match *self {
+            ValueType::BV(ref b) => b.doc(),
+            ValueType::Lane(l) => l.doc(),
+            ValueType::Special(s) => s.doc(),
+            ValueType::Vector(ref v) => v.doc(),
+        }
+    }
+
+    /// Return the number of bits in a lane.
+    pub fn lane_bits(&self) -> u64 {
+        match *self {
+            ValueType::BV(ref b) => b.lane_bits(),
+            ValueType::Lane(l) => l.lane_bits(),
+            ValueType::Special(s) => s.lane_bits(),
+            ValueType::Vector(ref v) => v.lane_bits(),
+        }
+    }
+
+    /// Return the number of lanes.
+    pub fn lane_count(&self) -> u64 {
+        match *self {
+            ValueType::Vector(ref v) => v.lane_count(),
+            _ => 1,
+        }
+    }
+
+    /// Find the number of bytes that this type occupies in memory.
+    pub fn membytes(&self) -> u64 {
+        self.width() / 8
+    }
+
+    /// Find the unique number associated with this type.
+    pub fn number(&self) -> Option<u8> {
+        match *self {
+            ValueType::BV(_) => None,
+            ValueType::Lane(l) => Some(l.number()),
+            ValueType::Special(s) => Some(s.number()),
+            ValueType::Vector(ref v) => Some(v.number()),
+        }
+    }
+
+    /// Return the name of this type for generated Rust source files.
+    pub fn _rust_name(&self) -> String {
+        format!("{}{}", _RUST_NAME_PREFIX, self.to_string().to_uppercase())
+    }
+
+    /// Return true iff:
+    ///     1. self and other have equal number of lanes
+    ///     2. each lane in self has at least as many bits as a lane in other
+    pub fn _wider_or_equal(&self, rhs: &ValueType) -> bool {
+        (self.lane_count() == rhs.lane_count()) && (self.lane_bits() >= rhs.lane_bits())
+    }
+
+    /// Return the total number of bits of an instance of this type.
+    pub fn width(&self) -> u64 {
+        self.lane_count() * self.lane_bits()
+    }
+}
+
+impl fmt::Display for ValueType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            ValueType::BV(ref b) => b.fmt(f),
+            ValueType::Lane(l) => l.fmt(f),
+            ValueType::Special(s) => s.fmt(f),
+            ValueType::Vector(ref v) => v.fmt(f),
+        }
+    }
+}
+
+/// Create a ValueType from a given bitvector type.
+impl From<BVType> for ValueType {
+    fn from(bv: BVType) -> Self {
+        ValueType::BV(bv)
+    }
+}
+
+/// Create a ValueType from a given lane type.
+impl From<LaneType> for ValueType {
+    fn from(lane: LaneType) -> Self {
+        ValueType::Lane(lane)
+    }
+}
+
+/// Create a ValueType from a given special type.
+impl From<SpecialType> for ValueType {
+    fn from(spec: SpecialType) -> Self {
+        ValueType::Special(spec)
+    }
+}
+
+/// Create a ValueType from a given vector type.
+impl From<VectorType> for ValueType {
+    fn from(vector: VectorType) -> Self {
+        ValueType::Vector(vector)
+    }
+}
+
+/// A concrete scalar type that can appear as a vector lane too.
+#[derive(Clone, Copy)]
+pub enum LaneType {
+    BoolType(base_types::Bool),
+    FloatType(base_types::Float),
+    IntType(base_types::Int),
+}
+
+impl LaneType {
+    /// Return a string containing the documentation comment for this lane type.
+    pub fn doc(self) -> String {
+        match self {
+            LaneType::BoolType(_) => format!("A boolean type with {} bits.", self.lane_bits()),
+            LaneType::FloatType(base_types::Float::F32) => String::from(
+                "A 32-bit floating point type represented in the IEEE 754-2008
+                *binary32* interchange format. This corresponds to the :c:type:`float`
+                type in most C implementations.",
+            ),
+            LaneType::FloatType(base_types::Float::F64) => String::from(
+                "A 64-bit floating point type represented in the IEEE 754-2008
+                *binary64* interchange format. This corresponds to the :c:type:`double`
+                type in most C implementations.",
+            ),
+            LaneType::IntType(_) if self.lane_bits() < 32 => format!(
+                "An integer type with {} bits.
+                WARNING: arithmetic on {}bit integers is incomplete",
+                self.lane_bits(),
+                self.lane_bits()
+            ),
+            LaneType::IntType(_) => format!("An integer type with {} bits.", self.lane_bits()),
+        }
+    }
+
+    /// Return the number of bits in a lane.
+    pub fn lane_bits(self) -> u64 {
+        match self {
+            LaneType::BoolType(ref b) => *b as u64,
+            LaneType::FloatType(ref f) => *f as u64,
+            LaneType::IntType(ref i) => *i as u64,
+        }
+    }
+
+    /// Find the unique number associated with this lane type.
+    pub fn number(self) -> u8 {
+        LANE_BASE
+            + match self {
+                LaneType::BoolType(base_types::Bool::B1) => 0,
+                LaneType::BoolType(base_types::Bool::B8) => 1,
+                LaneType::BoolType(base_types::Bool::B16) => 2,
+                LaneType::BoolType(base_types::Bool::B32) => 3,
+                LaneType::BoolType(base_types::Bool::B64) => 4,
+                LaneType::IntType(base_types::Int::I8) => 5,
+                LaneType::IntType(base_types::Int::I16) => 6,
+                LaneType::IntType(base_types::Int::I32) => 7,
+                LaneType::IntType(base_types::Int::I64) => 8,
+                LaneType::FloatType(base_types::Float::F32) => 9,
+                LaneType::FloatType(base_types::Float::F64) => 10,
+            }
+    }
+}
+
+impl fmt::Display for LaneType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            LaneType::BoolType(_) => write!(f, "b{}", self.lane_bits()),
+            LaneType::FloatType(_) => write!(f, "f{}", self.lane_bits()),
+            LaneType::IntType(_) => write!(f, "i{}", self.lane_bits()),
+        }
+    }
+}
+
+impl fmt::Debug for LaneType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let inner_msg = format!("bits={}", self.lane_bits());
+        write!(
+            f,
+            "{}",
+            match *self {
+                LaneType::BoolType(_) => format!("BoolType({})", inner_msg),
+                LaneType::FloatType(_) => format!("FloatType({})", inner_msg),
+                LaneType::IntType(_) => format!("IntType({})", inner_msg),
+            }
+        )
+    }
+}
+
+/// Create a LaneType from a given bool variant.
+impl From<base_types::Bool> for LaneType {
+    fn from(b: base_types::Bool) -> Self {
+        LaneType::BoolType(b)
+    }
+}
+
+/// Create a LaneType from a given float variant.
+impl From<base_types::Float> for LaneType {
+    fn from(f: base_types::Float) -> Self {
+        LaneType::FloatType(f)
+    }
+}
+
+/// Create a LaneType from a given int variant.
+impl From<base_types::Int> for LaneType {
+    fn from(i: base_types::Int) -> Self {
+        LaneType::IntType(i)
+    }
+}
+
+/// An iterator for different lane types.
+pub struct LaneTypeIterator {
+    bool_iter: base_types::BoolIterator,
+    int_iter: base_types::IntIterator,
+    float_iter: base_types::FloatIterator,
+}
+
+impl LaneTypeIterator {
+    /// Create a new lane type iterator.
+    fn new() -> Self {
+        Self {
+            bool_iter: base_types::BoolIterator::new(),
+            int_iter: base_types::IntIterator::new(),
+            float_iter: base_types::FloatIterator::new(),
+        }
+    }
+}
+
+impl Iterator for LaneTypeIterator {
+    type Item = LaneType;
+    fn next(&mut self) -> Option<Self::Item> {
+        if let Some(b) = self.bool_iter.next() {
+            Some(LaneType::from(b))
+        } else if let Some(i) = self.int_iter.next() {
+            Some(LaneType::from(i))
+        } else if let Some(f) = self.float_iter.next() {
+            Some(LaneType::from(f))
+        } else {
+            None
+        }
+    }
+}
+
+/// A concrete SIMD vector type.
+///
+/// A vector type has a lane type which is an instance of `LaneType`,
+/// and a positive number of lanes.
+pub struct VectorType {
+    base: LaneType,
+    lanes: u64,
+}
+
+impl VectorType {
+    /// Initialize a new integer type with `n` bits.
+    pub fn new(base: LaneType, lanes: u64) -> Self {
+        Self { base, lanes }
+    }
+
+    /// Return a string containing the documentation comment for this vector type.
+    pub fn doc(&self) -> String {
+        format!(
+            "A SIMD vector with {} lanes containing a `{}` each.",
+            self.lane_count(),
+            self.base
+        )
+    }
+
+    /// Return the number of bits in a lane.
+    pub fn lane_bits(&self) -> u64 {
+        self.base.lane_bits()
+    }
+
+    /// Return the number of lanes.
+    pub fn lane_count(&self) -> u64 {
+        self.lanes
+    }
+
+    /// Find the unique number associated with this vector type.
+    ///
+    /// Vector types are encoded with the lane type in the low 4 bits and
+    /// log2(lanes) in the high 4 bits, giving a range of 2-256 lanes.
+    pub fn number(&self) -> u8 {
+        let lanes_log_2: u32 = 63 - self.lane_count().leading_zeros();
+        let base_num = u32::from(self.base.number());
+        let num = (lanes_log_2 << 4) + base_num;
+        num as u8
+    }
+}
+
+impl fmt::Display for VectorType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}x{}", self.base, self.lane_count())
+    }
+}
+
+impl fmt::Debug for VectorType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "VectorType(base={}, lanes={})",
+            self.base,
+            self.lane_count()
+        )
+    }
+}
+
+/// A flat bitvector type. Used for semantics description only.
+pub struct BVType {
+    bits: u64,
+}
+
+impl BVType {
+    /// Initialize a new bitvector type with `n` bits.
+    pub fn _new(bits: u64) -> Self {
+        Self { bits }
+    }
+
+    /// Return a string containing the documentation comment for this bitvector type.
+    pub fn doc(&self) -> String {
+        format!("A bitvector type with {} bits.", self.bits)
+    }
+
+    /// Return the number of bits in a lane.
+    pub fn lane_bits(&self) -> u64 {
+        self.bits
+    }
+}
+
+impl fmt::Display for BVType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "bv{}", self.bits)
+    }
+}
+
+impl fmt::Debug for BVType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "BVType(bits={})", self.lane_bits())
+    }
+}
+
+/// A concrete scalar type that is neither a vector nor a lane type.
+///
+/// Special types cannot be used to form vectors.
+#[derive(Clone, Copy)]
+pub enum SpecialType {
+    Flag(base_types::Flag),
+}
+
+impl SpecialType {
+    /// Return a string containing the documentation comment for this special type.
+    pub fn doc(self) -> String {
+        match self {
+            SpecialType::Flag(base_types::Flag::IFlags) => String::from(
+                "CPU flags representing the result of an integer comparison. These flags
+                can be tested with an :type:`intcc` condition code.",
+            ),
+            SpecialType::Flag(base_types::Flag::FFlags) => String::from(
+                "CPU flags representing the result of a floating point comparison. These
+                flags can be tested with a :type:`floatcc` condition code.",
+            ),
+        }
+    }
+
+    /// Return the number of bits in a lane.
+    pub fn lane_bits(self) -> u64 {
+        match self {
+            SpecialType::Flag(_) => 0,
+        }
+    }
+
+    /// Find the unique number associated with this special type.
+    pub fn number(self) -> u8 {
+        match self {
+            SpecialType::Flag(base_types::Flag::IFlags) => 1,
+            SpecialType::Flag(base_types::Flag::FFlags) => 2,
+        }
+    }
+}
+
+impl fmt::Display for SpecialType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            SpecialType::Flag(base_types::Flag::IFlags) => write!(f, "iflags"),
+            SpecialType::Flag(base_types::Flag::FFlags) => write!(f, "fflags"),
+        }
+    }
+}
+
+impl fmt::Debug for SpecialType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "{}",
+            match *self {
+                SpecialType::Flag(_) => format!("FlagsType({})", self),
+            }
+        )
+    }
+}
+
+impl From<base_types::Flag> for SpecialType {
+    fn from(f: base_types::Flag) -> Self {
+        SpecialType::Flag(f)
+    }
+}
+
+pub struct SpecialTypeIterator {
+    flag_iter: base_types::FlagIterator,
+}
+
+impl SpecialTypeIterator {
+    fn new() -> Self {
+        Self {
+            flag_iter: base_types::FlagIterator::new(),
+        }
+    }
+}
+
+impl Iterator for SpecialTypeIterator {
+    type Item = SpecialType;
+    fn next(&mut self) -> Option<Self::Item> {
+        if let Some(f) = self.flag_iter.next() {
+            Some(SpecialType::from(f))
+        } else {
+            None
+        }
+    }
+}

cranelift/codegen/meta/src/constant_hash.rs

@@ -0,0 +1,49 @@
+pub fn simple_hash(s: &str) -> usize {
+    let mut h: u32 = 5381;
+    for c in s.chars() {
+        h = (h ^ c as u32).wrapping_add(h.rotate_right(6));
+    }
+    h as usize
+}
+
+/// Compute an open addressed, quadratically probed hash table containing
+/// `items`. The returned table is a list containing the elements of the
+/// iterable `items` and `None` in unused slots.
+pub fn generate_table<T, H: Fn(&T) -> usize>(items: &Vec<T>, hash_function: H) -> Vec<Option<&T>> {
+    let size = (1.20 * items.len() as f64) as usize;
+    // TODO do we really need the multiply by two here?
+    let size = if size.is_power_of_two() {
+        size * 2
+    } else {
+        size.next_power_of_two()
+    };
+
+    let mut table: Vec<Option<&T>> = vec![None; size];
+
+    for i in items {
+        let mut h = hash_function(i) % size;
+        let mut s = 0;
+        while table[h].is_some() {
+            s += 1;
+            h = (h + s) % size;
+        }
+        table[h] = Some(i);
+    }
+
+    table
+}
+
+#[test]
+fn test_generate_table() {
+    let v = vec!["Hello".to_string(), "world".to_string()];
+    let table = generate_table(&v, |s| simple_hash(&s));
+    assert_eq!(
+        table,
+        vec![
+            None,
+            Some(&"Hello".to_string()),
+            Some(&"world".to_string()),
+            None
+        ]
+    );
+}

cranelift/codegen/meta/src/error.rs

@@ -0,0 +1,47 @@
+use std::fmt;
+use std::io;
+
+/// An error that occurred when the cranelift_codegen_meta crate was generating
+/// source files for the cranelift_codegen crate.
+#[derive(Debug)]
+pub struct Error {
+    inner: Box<ErrorInner>,
+}
+
+impl Error {
+    /// Create a new error object with the given message.
+    pub fn with_msg<S: Into<String>>(msg: S) -> Error {
+        Error {
+            inner: Box::new(ErrorInner::Msg(msg.into())),
+        }
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.inner)
+    }
+}
+
+impl From<io::Error> for Error {
+    fn from(e: io::Error) -> Self {
+        Error {
+            inner: Box::new(ErrorInner::IoError(e)),
+        }
+    }
+}
+
+#[derive(Debug)]
+enum ErrorInner {
+    Msg(String),
+    IoError(io::Error),
+}
+
+impl fmt::Display for ErrorInner {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            ErrorInner::Msg(ref s) => write!(f, "{}", s),
+            ErrorInner::IoError(ref e) => write!(f, "{}", e),
+        }
+    }
+}

cranelift/codegen/meta/src/gen_registers.rs

@@ -0,0 +1,138 @@
+use crate::cdsl::isa::TargetIsa;
+use crate::cdsl::regs::{RegBank, RegClass};
+use crate::error;
+use crate::srcgen::Formatter;
+use cranelift_entity::EntityRef;
+
+fn gen_regbank(fmt: &mut Formatter, reg_bank: &RegBank) {
+    let names = if reg_bank.names.len() > 0 {
+        format!(r#""{}""#, reg_bank.names.join(r#"", ""#))
+    } else {
+        "".to_string()
+    };
+    fmt.line("RegBank {");
+    fmt.indent(|fmt| {
+        fmt.line(&format!(r#"name: "{}","#, reg_bank.name));
+        fmt.line(&format!("first_unit: {},", reg_bank.first_unit));
+        fmt.line(&format!("units: {},", reg_bank.units));
+        fmt.line(&format!("names: &[{}],", names));
+        fmt.line(&format!(r#"prefix: "{}","#, reg_bank.prefix));
+        fmt.line(&format!("first_toprc: {},", reg_bank.toprcs[0].index()));
+        fmt.line(&format!("num_toprcs: {},", reg_bank.toprcs.len()));
+        fmt.line(&format!(
+            "pressure_tracking: {},",
+            if reg_bank.pressure_tracking {
+                "true"
+            } else {
+                "false"
+            }
+        ));
+    });
+    fmt.line("},");
+}
+
+fn gen_regclass(isa: &TargetIsa, reg_class: &RegClass, fmt: &mut Formatter) {
+    let reg_bank = isa.reg_banks.get(reg_class.bank).unwrap();
+
+    let mask: Vec<String> = reg_class
+        .mask(reg_bank.first_unit)
+        .iter()
+        .map(|x| format!("0x{:08x}", x))
+        .collect();
+    let mask = mask.join(", ");
+
+    fmt.line(&format!(
+        "pub static {}_DATA: RegClassData = RegClassData {{",
+        reg_class.name
+    ));
+    fmt.indent(|fmt| {
+        fmt.line(&format!(r#"name: "{}","#, reg_class.name));
+        fmt.line(&format!("index: {},", reg_class.index.index()));
+        fmt.line(&format!("width: {},", reg_class.width));
+        fmt.line(&format!("bank: {},", reg_class.bank.index()));
+        fmt.line(&format!("toprc: {},", reg_class.toprc.index()));
+        fmt.line(&format!(
+            "first: {},",
+            reg_bank.first_unit + reg_class.start
+        ));
+        fmt.line(&format!("subclasses: {:#x},", reg_class.subclass_mask()));
+        fmt.line(&format!("mask: [{}],", mask));
+        fmt.line("info: &INFO,");
+    });
+    fmt.line("};");
+    fmt.line("#[allow(dead_code)]");
+    fmt.line(&format!(
+        "pub static {}: RegClass = &{}_DATA;",
+        reg_class.name, reg_class.name
+    ));
+}
+
+fn gen_regbank_units(reg_bank: &RegBank, fmt: &mut Formatter) {
+    for unit in 0..reg_bank.units {
+        let v = unit + reg_bank.first_unit;
+        if (unit as usize) < reg_bank.names.len() {
+            fmt.line(&format!("{} = {},", reg_bank.names[unit as usize], v));
+            continue;
+        }
+        fmt.line(&format!("{}{} = {},", reg_bank.prefix, unit, v));
+    }
+}
+
+fn gen_isa(isa: &TargetIsa, fmt: &mut Formatter) {
+    // Emit RegInfo.
+    fmt.line("pub static INFO: RegInfo = RegInfo {");
+
+    fmt.indent(|fmt| {
+        fmt.line("banks: &[");
+        // Bank descriptors.
+        fmt.indent(|fmt| {
+            for reg_bank in isa.reg_banks.values() {
+                gen_regbank(fmt, &reg_bank);
+            }
+        });
+        fmt.line("],");
+        // References to register classes.
+        fmt.line("classes: &[");
+        fmt.indent(|fmt| {
+            for reg_class in isa.reg_classes.values() {
+                fmt.line(&format!("&{}_DATA,", reg_class.name));
+            }
+        });
+        fmt.line("],");
+    });
+    fmt.line("};");
+
+    // Register class descriptors.
+    for rc in isa.reg_classes.values() {
+        gen_regclass(&isa, rc, fmt);
+    }
+
+    // Emit constants for all the register units.
+    fmt.line("#[allow(dead_code, non_camel_case_types)]");
+    fmt.line("#[derive(Clone, Copy)]");
+    fmt.line("pub enum RU {");
+    fmt.indent(|fmt| {
+        for reg_bank in isa.reg_banks.values() {
+            gen_regbank_units(reg_bank, fmt);
+        }
+    });
+    fmt.line("}");
+
+    // Emit Into conversion for the RU class.
+    fmt.line("impl Into<RegUnit> for RU {");
+    fmt.indent(|fmt| {
+        fmt.line("fn into(self) -> RegUnit {");
+        fmt.indent(|fmt| {
+            fmt.line("self as RegUnit");
+        });
+        fmt.line("}")
+    });
+    fmt.line("}");
+}
+
+pub fn generate(isa: &TargetIsa, base_filename: &str, out_dir: &str) -> Result<(), error::Error> {
+    let mut fmt = Formatter::new();
+    gen_isa(&isa, &mut fmt);
+    fmt.update_file(&format!("{}-{}.rs", base_filename, isa.name), out_dir)?;
+    Ok(())
+}

cranelift/codegen/meta/src/gen_settings.rs

@@ -0,0 +1,448 @@
+use crate::base;
+use crate::cdsl::camel_case;
+use crate::cdsl::isa::TargetIsa;
+use crate::cdsl::settings::{
+    BoolSetting, Predicate, Preset, Setting, SettingGroup, SpecificSetting,
+};
+use crate::constant_hash::{generate_table, simple_hash};
+use crate::error;
+use crate::srcgen::{Formatter, Match};
+use crate::unique_table::UniqueTable;
+use std::collections::HashMap;
+
+enum ParentGroup {
+    None,
+    Shared,
+}
+
+/// Emits the constructor of the Flags structure.
+fn gen_constructor(group: &SettingGroup, parent: ParentGroup, fmt: &mut Formatter) {
+    let args = match parent {
+        ParentGroup::None => "builder: Builder",
+        ParentGroup::Shared => "shared: &settings::Flags, builder: Builder",
+    };
+    fmt.line("impl Flags {");
+    fmt.indent(|fmt| {
+        fmt.doc_comment(&format!("Create flags {} settings group.", group.name));
+        fmt.line("#[allow(unused_variables)]");
+        fmt.line(&format!("pub fn new({}) -> Self {{", args));
+        fmt.indent(|fmt| {
+            fmt.line(&format!(
+                "let bvec = builder.state_for(\"{}\");",
+                group.name
+            ));
+            fmt.line(&format!(
+                "let mut {} = Self {{ bytes: [0; {}] }};",
+                group.name,
+                group.byte_size()
+            ));
+            fmt.line(&format!(
+                "debug_assert_eq!(bvec.len(), {});",
+                group.settings_size
+            ));
+            fmt.line(&format!(
+                "{}.bytes[0..{}].copy_from_slice(&bvec);",
+                group.name, group.settings_size
+            ));
+
+            // Now compute the predicates.
+            for p in &group.predicates {
+                fmt.comment(&format!("Precompute #{}.", p.number));
+                fmt.line(&format!("if {} {{", p.render(group)));
+                fmt.indent(|fmt| {
+                    fmt.line(&format!(
+                        "{}.bytes[{}] |= 1 << {};",
+                        group.name,
+                        group.bool_start_byte_offset + p.number / 8,
+                        p.number % 8
+                    ));
+                });
+                fmt.line("}");
+            }
+
+            fmt.line(group.name);
+        });
+        fmt.line("}");
+    });
+    fmt.line("}");
+}
+
+/// Emit Display and FromStr implementations for enum settings.
+fn gen_to_and_from_str(name: &str, values: &[&'static str], fmt: &mut Formatter) {
+    fmt.line(&format!("impl fmt::Display for {} {{", name));
+    fmt.indent(|fmt| {
+        fmt.line("fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {");
+        fmt.indent(|fmt| {
+            fmt.line("f.write_str(match *self {");
+            fmt.indent(|fmt| {
+                for v in values.iter() {
+                    fmt.line(&format!("{}::{} => \"{}\",", name, camel_case(v), v));
+                }
+            });
+            fmt.line("})");
+        });
+        fmt.line("}");
+    });
+    fmt.line("}");
+
+    fmt.line(&format!("impl str::FromStr for {} {{", name));
+    fmt.indent(|fmt| {
+        fmt.line("type Err = ();");
+        fmt.line("fn from_str(s: &str) -> Result<Self, Self::Err> {");
+        fmt.indent(|fmt| {
+            fmt.line("match s {");
+            fmt.indent(|fmt| {
+                for v in values.iter() {
+                    fmt.line(&format!("\"{}\" => Ok({}::{}),", v, name, camel_case(v)));
+                }
+                fmt.line("_ => Err(()),");
+            });
+            fmt.line("}");
+        });
+        fmt.line("}");
+    });
+    fmt.line("}");
+}
+
+/// Emit real enum for the Enum settings.
+fn gen_enum_types(group: &SettingGroup, fmt: &mut Formatter) {
+    for setting in group.settings.iter() {
+        let values = match setting.specific {
+            SpecificSetting::Bool(_) | SpecificSetting::Num(_) => continue,
+            SpecificSetting::Enum(ref values) => values,
+        };
+        let name = camel_case(setting.name);
+
+        fmt.doc_comment(&format!("Values for `{}.{}`.", group.name, setting.name));
+        fmt.line("#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]");
+        fmt.line(&format!("pub enum {} {{", name));
+        fmt.indent(|fmt| {
+            for v in values.iter() {
+                fmt.doc_comment(&format!("`{}`.", v));
+                fmt.line(&format!("{},", camel_case(v)));
+            }
+        });
+        fmt.line("}");
+
+        gen_to_and_from_str(&name, values, fmt);
+    }
+}
+
+/// Emit a getter function for `setting`.
+fn gen_getter(setting: &Setting, fmt: &mut Formatter) {
+    fmt.doc_comment(setting.comment);
+    match setting.specific {
+        SpecificSetting::Bool(BoolSetting {
+            predicate_number, ..
+        }) => {
+            fmt.line(&format!("pub fn {}(&self) -> bool {{", setting.name));
+            fmt.indent(|fmt| {
+                fmt.line(&format!("self.numbered_predicate({})", predicate_number));
+            });
+            fmt.line("}");
+        }
+        SpecificSetting::Enum(ref values) => {
+            let ty = camel_case(setting.name);
+            fmt.line(&format!("pub fn {}(&self) -> {} {{", setting.name, ty));
+            fmt.indent(|fmt| {
+                let mut m = Match::new(format!("self.bytes[{}]", setting.byte_offset));
+                for (i, v) in values.iter().enumerate() {
+                    m.arm(
+                        format!("{}", i),
+                        vec![],
+                        format!("{}::{}", ty, camel_case(v)),
+                    );
+                }
+                m.arm("_", vec![], "panic!(\"Invalid enum value\")");
+                fmt.add_match(m);
+            });
+            fmt.line("}");
+        }
+        SpecificSetting::Num(_) => {
+            fmt.line(&format!("pub fn {}(&self) -> u8 {{", setting.name));
+            fmt.indent(|fmt| {
+                fmt.line(&format!("self.bytes[{}]", setting.byte_offset));
+            });
+            fmt.line("}");
+        }
+    }
+}
+
+fn gen_pred_getter(predicate: &Predicate, group: &SettingGroup, fmt: &mut Formatter) {
+    fmt.doc_comment(&format!(
+        "Computed predicate `{}`.",
+        predicate.render(group)
+    ));
+    fmt.line(&format!("pub fn {}(&self) -> bool {{", predicate.name));
+    fmt.indent(|fmt| {
+        fmt.line(&format!("self.numbered_predicate({})", predicate.number));
+    });
+    fmt.line("}");
+}
+
+/// Emits getters for each setting value.
+fn gen_getters(group: &SettingGroup, fmt: &mut Formatter) {
+    fmt.doc_comment("User-defined settings.");
+    fmt.line("#[allow(dead_code)]");
+    fmt.line("impl Flags {");
+    fmt.indent(|fmt| {
+        fmt.doc_comment("Get a view of the boolean predicates.");
+        fmt.line("pub fn predicate_view(&self) -> ::settings::PredicateView {");
+        fmt.indent(|fmt| {
+            fmt.line(&format!(
+                "::settings::PredicateView::new(&self.bytes[{}..])",
+                group.bool_start_byte_offset
+            ));
+        });
+        fmt.line("}");
+
+        if group.settings.len() > 0 {
+            fmt.doc_comment("Dynamic numbered predicate getter.");
+            fmt.line("fn numbered_predicate(&self, p: usize) -> bool {");
+            fmt.indent(|fmt| {
+                fmt.line(&format!(
+                    "self.bytes[{} + p / 8] & (1 << (p % 8)) != 0",
+                    group.bool_start_byte_offset
+                ));
+            });
+            fmt.line("}");
+        }
+
+        for setting in &group.settings {
+            gen_getter(&setting, fmt);
+        }
+        for predicate in &group.predicates {
+            gen_pred_getter(&predicate, &group, fmt);
+        }
+    });
+    fmt.line("}");
+}
+
+#[derive(Hash, PartialEq, Eq)]
+enum SettingOrPreset<'a> {
+    Setting(&'a Setting),
+    Preset(&'a Preset),
+}
+
+impl<'a> SettingOrPreset<'a> {
+    fn name(&self) -> &str {
+        match *self {
+            SettingOrPreset::Setting(s) => s.name,
+            SettingOrPreset::Preset(p) => p.name,
+        }
+    }
+}
+
+/// Emits DESCRIPTORS, ENUMERATORS, HASH_TABLE and PRESETS.
+fn gen_descriptors(group: &SettingGroup, fmt: &mut Formatter) {
+    let mut enum_table: UniqueTable<&'static str> = UniqueTable::new();
+
+    let mut descriptor_index_map: HashMap<SettingOrPreset, usize> = HashMap::new();
+
+    // Generate descriptors.
+    fmt.line(&format!(
+        "static DESCRIPTORS: [detail::Descriptor; {}] = [",
+        group.settings.len() + group.presets.len()
+    ));
+    fmt.indent(|fmt| {
+        for (idx, setting) in group.settings.iter().enumerate() {
+            fmt.line("detail::Descriptor {");
+            fmt.indent(|fmt| {
+                fmt.line(&format!("name: \"{}\",", setting.name));
+                fmt.line(&format!("offset: {},", setting.byte_offset));
+                match setting.specific {
+                    SpecificSetting::Bool(BoolSetting { bit_offset, .. }) => {
+                        fmt.line(&format!(
+                            "detail: detail::Detail::Bool {{ bit: {} }},",
+                            bit_offset
+                        ));
+                    }
+                    SpecificSetting::Enum(ref values) => {
+                        let offset = enum_table.add(values);
+                        fmt.line(&format!(
+                            "detail: detail::Detail::Enum {{ last: {}, enumerators: {} }},",
+                            values.len() - 1,
+                            offset
+                        ));
+                    }
+                    SpecificSetting::Num(_) => {
+                        fmt.line("detail: detail::Detail::Num,");
+                    }
+                }
+
+                descriptor_index_map.insert(SettingOrPreset::Setting(setting), idx);
+            });
+            fmt.line("},");
+        }
+
+        for (idx, preset) in group.presets.iter().enumerate() {
+            fmt.line("detail::Descriptor {");
+            fmt.indent(|fmt| {
+                fmt.line(&format!("name: \"{}\",", preset.name));
+                fmt.line(&format!("offset: {},", (idx as u8) * group.settings_size));
+                fmt.line("detail: detail::Detail::Preset,");
+            });
+            fmt.line("},");
+
+            descriptor_index_map.insert(SettingOrPreset::Preset(preset), idx);
+        }
+    });
+    fmt.line("];");
+
+    // Generate enumerators.
+    fmt.line(&format!(
+        "static ENUMERATORS: [&str; {}] = [",
+        enum_table.len()
+    ));
+    fmt.indent(|fmt| {
+        for enum_val in enum_table.iter() {
+            fmt.line(&format!("\"{}\",", enum_val));
+        }
+    });
+    fmt.line("];");
+
+    // Generate hash table.
+    let mut hash_entries: Vec<SettingOrPreset> = Vec::new();
+    hash_entries.extend(
+        group
+            .settings
+            .iter()
+            .map(|x| SettingOrPreset::Setting(x))
+            .collect::<Vec<SettingOrPreset>>(),
+    );
+    hash_entries.extend(
+        group
+            .presets
+            .iter()
+            .map(|x| SettingOrPreset::Preset(x))
+            .collect::<Vec<SettingOrPreset>>(),
+    );
+    let hash_table = generate_table(&hash_entries, |entry| simple_hash(entry.name()));
+    fmt.line(&format!(
+        "static HASH_TABLE: [u16; {}] = [",
+        hash_table.len()
+    ));
+    fmt.indent(|fmt| {
+        for h in &hash_table {
+            match *h {
+                Some(setting_or_preset) => fmt.line(&format!(
+                    "{},",
+                    &descriptor_index_map
+                        .get(setting_or_preset)
+                        .unwrap()
+                        .to_string()
+                )),
+                None => fmt.line("0xffff,"),
+            }
+        }
+    });
+    fmt.line("];");
+
+    // Generate presets.
+    fmt.line(&format!(
+        "static PRESETS: [(u8, u8); {}] = [",
+        group.presets.len()
+    ));
+    fmt.indent(|fmt| {
+        for preset in &group.presets {
+            fmt.comment(preset.name);
+            for (mask, value) in preset.layout(&group) {
+                fmt.line(&format!("(0b{:08b}, 0b{:08b}),", mask, value));
+            }
+        }
+    });
+    fmt.line("];");
+}
+
+fn gen_template(group: &SettingGroup, fmt: &mut Formatter) {
+    let mut default_bytes: Vec<u8> = vec![0; group.settings_size as usize];
+    for setting in &group.settings {
+        *default_bytes.get_mut(setting.byte_offset as usize).unwrap() |= setting.default_byte();
+    }
+
+    let default_bytes: Vec<String> = default_bytes
+        .iter()
+        .map(|x| format!("{:#04x}", x))
+        .collect();
+    let default_bytes_str = default_bytes.join(", ");
+
+    fmt.line("static TEMPLATE: detail::Template = detail::Template {");
+    fmt.indent(|fmt| {
+        fmt.line(&format!("name: \"{}\",", group.name));
+        fmt.line("descriptors: &DESCRIPTORS,");
+        fmt.line("enumerators: &ENUMERATORS,");
+        fmt.line("hash_table: &HASH_TABLE,");
+        fmt.line(&format!("defaults: &[{}],", default_bytes_str));
+        fmt.line("presets: &PRESETS,");
+    });
+    fmt.line("};");
+
+    fmt.doc_comment(&format!(
+        "Create a `settings::Builder` for the {} settings group.",
+        group.name
+    ));
+    fmt.line("pub fn builder() -> Builder {");
+    fmt.indent(|fmt| {
+        fmt.line("Builder::new(&TEMPLATE)");
+    });
+    fmt.line("}");
+}
+
+fn gen_display(group: &SettingGroup, fmt: &mut Formatter) {
+    fmt.line("impl fmt::Display for Flags {");
+    fmt.indent(|fmt| {
+        fmt.line("fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {");
+        fmt.indent(|fmt| {
+            fmt.line(&format!("writeln!(f, \"[{}]\")?;", group.name));
+            fmt.line("for d in &DESCRIPTORS {");
+            fmt.indent(|fmt| {
+                fmt.line("if !d.detail.is_preset() {");
+                fmt.indent(|fmt| {
+                    fmt.line("write!(f, \"{} = \", d.name)?;");
+                    fmt.line(
+                        "TEMPLATE.format_toml_value(d.detail, self.bytes[d.offset as usize], f)?;",
+                    );
+                    fmt.line("writeln!(f)?;");
+                });
+                fmt.line("}");
+            });
+            fmt.line("}");
+            fmt.line("Ok(())");
+        });
+        fmt.line("}")
+    });
+    fmt.line("}");
+}
+
+fn gen_group(group: &SettingGroup, parent: ParentGroup, fmt: &mut Formatter) {
+    // Generate struct.
+    fmt.line("#[derive(Clone)]");
+    fmt.doc_comment(&format!("Flags group `{}`.", group.name));
+    fmt.line("pub struct Flags {");
+    fmt.indent(|fmt| {
+        fmt.line(&format!("bytes: [u8; {}],", group.byte_size()));
+    });
+    fmt.line("}");
+
+    gen_constructor(group, parent, fmt);
+    gen_enum_types(group, fmt);
+    gen_getters(group, fmt);
+    gen_descriptors(group, fmt);
+    gen_template(group, fmt);
+    gen_display(group, fmt);
+}
+
+pub fn generate_common(filename: &str, out_dir: &str) -> Result<SettingGroup, error::Error> {
+    let settings = base::settings::generate();
+    let mut fmt = Formatter::new();
+    gen_group(&settings, ParentGroup::None, &mut fmt);
+    fmt.update_file(filename, out_dir)?;
+    Ok(settings)
+}
+
+pub fn generate(isa: &TargetIsa, prefix: &str, out_dir: &str) -> Result<(), error::Error> {
+    let mut fmt = Formatter::new();
+    gen_group(&isa.settings, ParentGroup::Shared, &mut fmt);
+    fmt.update_file(&format!("{}-{}.rs", prefix, isa.name), out_dir)?;
+    Ok(())
+}

cranelift/codegen/meta/src/gen_types.rs

@@ -0,0 +1,73 @@
+//! Generate sources with type info.
+//!
+//! This generates a `types.rs` file which is included in
+//! `cranelift-codegen/ir/types.rs`. The file provides constant definitions for the
+//! most commonly used types, including all of the scalar types.
+//!
+//! This ensures that the metaprogram and the generated program see the same
+//! type numbering.
+
+use crate::cdsl::types as cdsl_types;
+use crate::error;
+use crate::srcgen;
+
+/// Emit a constant definition of a single value type.
+fn emit_type(ty: &cdsl_types::ValueType, fmt: &mut srcgen::Formatter) -> Result<(), error::Error> {
+    let name = ty.to_string().to_uppercase();
+    let number = ty.number().ok_or_else(|| {
+        error::Error::with_msg(format!(
+            "Could not emit type `{}` which has no number.",
+            name
+        ))
+    })?;
+
+    let definition = format!("pub const {}: Type = Type({:#x});\n", name, number);
+
+    fmt.doc_comment(&ty.doc());
+    fmt.line(&definition);
+
+    Ok(())
+}
+
+/// Emit definition for all vector types with `bits` total size.
+fn emit_vectors(bits: u64, fmt: &mut srcgen::Formatter) -> Result<(), error::Error> {
+    let vec_size: u64 = bits / 8;
+    for vec in cdsl_types::ValueType::all_lane_types()
+        .map(|ty| (ty, cdsl_types::ValueType::from(ty).membytes()))
+        .filter(|&(_, lane_size)| lane_size != 0 && lane_size < vec_size)
+        .map(|(ty, lane_size)| (ty, vec_size / lane_size))
+        .map(|(ty, lanes)| cdsl_types::VectorType::new(ty, lanes))
+    {
+        emit_type(&cdsl_types::ValueType::from(vec), fmt)?;
+    }
+
+    Ok(())
+}
+
+/// Emit types using the given formatter object.
+fn emit_types(fmt: &mut srcgen::Formatter) -> Result<(), error::Error> {
+    // Emit all of the special types, such as types for CPU flags.
+    for spec in cdsl_types::ValueType::all_special_types().map(cdsl_types::ValueType::from) {
+        emit_type(&spec, fmt)?;
+    }
+
+    // Emit all of the lane types, such integers, floats, and booleans.
+    for ty in cdsl_types::ValueType::all_lane_types().map(cdsl_types::ValueType::from) {
+        emit_type(&ty, fmt)?;
+    }
+
+    // Emit vector definitions for common SIMD sizes.
+    for vec_size in &[64_u64, 128, 256, 512] {
+        emit_vectors(*vec_size, fmt)?;
+    }
+
+    Ok(())
+}
+
+/// Generate the types file.
+pub fn generate(filename: &str, out_dir: &str) -> Result<(), error::Error> {
+    let mut fmt = srcgen::Formatter::new();
+    emit_types(&mut fmt)?;
+    fmt.update_file(filename, out_dir)?;
+    Ok(())
+}

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

@@ -0,0 +1,45 @@
+use crate::cdsl::isa::{TargetIsa, TargetIsaBuilder};
+use crate::cdsl::regs::{RegBankBuilder, RegClassBuilder};
+use crate::cdsl::settings::{SettingGroup, SettingGroupBuilder};
+
+fn define_settings(_shared: &SettingGroup) -> SettingGroup {
+    let setting = SettingGroupBuilder::new("arm32");
+    setting.finish()
+}
+
+pub fn define(shared_settings: &SettingGroup) -> TargetIsa {
+    let mut isa = TargetIsaBuilder::new("arm32", define_settings(shared_settings));
+
+    let builder = RegBankBuilder::new("FloatRegs", "s")
+        .units(64)
+        .track_pressure(true);
+    let float_regs = isa.add_reg_bank(builder);
+
+    let builder = RegBankBuilder::new("IntRegs", "r")
+        .units(16)
+        .track_pressure(true);
+    let int_regs = isa.add_reg_bank(builder);
+
+    let builder = RegBankBuilder::new("FlagRegs", "")
+        .units(1)
+        .names(vec!["nzcv"])
+        .track_pressure(false);
+    let flag_reg = isa.add_reg_bank(builder);
+
+    let builder = RegClassBuilder::new_toplevel("S", float_regs).count(32);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("D", float_regs).width(2);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("Q", float_regs).width(4);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("GPR", int_regs);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("FLAG", flag_reg);
+    isa.add_reg_class(builder);
+
+    isa.finish()
+}

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

@@ -0,0 +1,41 @@
+use crate::cdsl::isa::{TargetIsa, TargetIsaBuilder};
+use crate::cdsl::regs::{RegBankBuilder, RegClassBuilder};
+use crate::cdsl::settings::{SettingGroup, SettingGroupBuilder};
+
+fn define_settings(_shared: &SettingGroup) -> SettingGroup {
+    let setting = SettingGroupBuilder::new("arm64");
+    setting.finish()
+}
+
+pub fn define(shared_settings: &SettingGroup) -> TargetIsa {
+    let mut isa = TargetIsaBuilder::new("arm64", define_settings(shared_settings));
+
+    // The `x31` regunit serves as the stack pointer / zero register depending on context. We
+    // reserve it and don't model the difference.
+    let builder = RegBankBuilder::new("IntRegs", "x")
+        .units(32)
+        .track_pressure(true);
+    let int_regs = isa.add_reg_bank(builder);
+
+    let builder = RegBankBuilder::new("FloatRegs", "v")
+        .units(32)
+        .track_pressure(true);
+    let float_regs = isa.add_reg_bank(builder);
+
+    let builder = RegBankBuilder::new("FlagRegs", "")
+        .units(1)
+        .names(vec!["nzcv"])
+        .track_pressure(false);
+    let flag_reg = isa.add_reg_bank(builder);
+
+    let builder = RegClassBuilder::new_toplevel("GPR", int_regs);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("FPR", float_regs);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("FLAG", flag_reg);
+    isa.add_reg_class(builder);
+
+    isa.finish()
+}

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

@@ -0,0 +1,72 @@
+use crate::cdsl::isa::TargetIsa;
+use crate::cdsl::settings::SettingGroup;
+use std::fmt;
+
+mod arm32;
+mod arm64;
+mod riscv;
+mod x86;
+
+/// Represents known ISA target.
+#[derive(Copy, Clone)]
+pub enum Isa {
+    Riscv,
+    X86,
+    Arm32,
+    Arm64,
+}
+
+impl Isa {
+    /// Creates isa target using name.
+    pub fn new(name: &str) -> Option<Self> {
+        Isa::all()
+            .iter()
+            .cloned()
+            .filter(|isa| isa.to_string() == name)
+            .next()
+    }
+
+    /// Creates isa target from arch.
+    pub fn from_arch(arch: &str) -> Option<Isa> {
+        Isa::all()
+            .iter()
+            .cloned()
+            .filter(|isa| isa.is_arch_applicable(arch))
+            .next()
+    }
+
+    /// Returns all supported isa targets.
+    pub fn all() -> [Isa; 4] {
+        [Isa::Riscv, Isa::X86, Isa::Arm32, Isa::Arm64]
+    }
+
+    /// Checks if arch is applicable for the isa target.
+    fn is_arch_applicable(&self, arch: &str) -> bool {
+        match *self {
+            Isa::Riscv => arch == "riscv",
+            Isa::X86 => ["x86_64", "i386", "i586", "i686"].contains(&arch),
+            Isa::Arm32 => arch.starts_with("arm") || arch.starts_with("thumb"),
+            Isa::Arm64 => arch == "aarch64",
+        }
+    }
+}
+
+impl fmt::Display for Isa {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Isa::Riscv => write!(f, "riscv"),
+            Isa::X86 => write!(f, "x86"),
+            Isa::Arm32 => write!(f, "arm32"),
+            Isa::Arm64 => write!(f, "arm64"),
+        }
+    }
+}
+
+pub fn define_all(shared_settings: &SettingGroup) -> Vec<TargetIsa> {
+    vec![
+        riscv::define(shared_settings),
+        arm32::define(shared_settings),
+        arm64::define(shared_settings),
+        x86::define(shared_settings),
+    ]
+}

cranelift/codegen/meta/src/isa/riscv/mod.rs

@@ -0,0 +1,77 @@
+use crate::cdsl::isa::{TargetIsa, TargetIsaBuilder};
+use crate::cdsl::regs::{RegBankBuilder, RegClassBuilder};
+use crate::cdsl::settings::{PredicateNode, SettingGroup, SettingGroupBuilder};
+
+fn define_settings(shared: &SettingGroup) -> SettingGroup {
+    let mut setting = SettingGroupBuilder::new("riscv");
+
+    let supports_m = setting.add_bool(
+        "supports_m",
+        "CPU supports the 'M' extension (mul/div)",
+        false,
+    );
+    let supports_a = setting.add_bool(
+        "supports_a",
+        "CPU supports the 'A' extension (atomics)",
+        false,
+    );
+    let supports_f = setting.add_bool(
+        "supports_f",
+        "CPU supports the 'F' extension (float)",
+        false,
+    );
+    let supports_d = setting.add_bool(
+        "supports_d",
+        "CPU supports the 'D' extension (double)",
+        false,
+    );
+
+    let enable_m = setting.add_bool(
+        "enable_m",
+        "Enable the use of 'M' instructions if available",
+        true,
+    );
+
+    setting.add_bool(
+        "enable_e",
+        "Enable the 'RV32E' instruction set with only 16 registers",
+        true,
+    );
+
+    let shared_enable_atomics = shared.get_bool("enable_atomics");
+    let shared_enable_float = shared.get_bool("enable_float");
+    let shared_enable_simd = shared.get_bool("enable_simd");
+
+    setting.add_predicate("use_m", predicate!(supports_m && enable_m));
+    setting.add_predicate("use_a", predicate!(supports_a && shared_enable_atomics));
+    setting.add_predicate("use_f", predicate!(supports_f && shared_enable_float));
+    setting.add_predicate("use_d", predicate!(supports_d && shared_enable_float));
+    setting.add_predicate(
+        "full_float",
+        predicate!(shared_enable_simd && supports_f && supports_d),
+    );
+
+    setting.finish()
+}
+
+pub fn define(shared_settings: &SettingGroup) -> TargetIsa {
+    let mut isa = TargetIsaBuilder::new("riscv", define_settings(shared_settings));
+
+    let builder = RegBankBuilder::new("IntRegs", "x")
+        .units(32)
+        .track_pressure(true);
+    let int_regs = isa.add_reg_bank(builder);
+
+    let builder = RegBankBuilder::new("FloatRegs", "f")
+        .units(32)
+        .track_pressure(true);
+    let float_regs = isa.add_reg_bank(builder);
+
+    let builder = RegClassBuilder::new_toplevel("GPR", int_regs);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("FPR", float_regs);
+    isa.add_reg_class(builder);
+
+    isa.finish()
+}

cranelift/codegen/meta/src/isa/x86/mod.rs

@@ -0,0 +1,116 @@
+use crate::cdsl::isa::{TargetIsa, TargetIsaBuilder};
+use crate::cdsl::regs::{RegBankBuilder, RegClassBuilder};
+use crate::cdsl::settings::{PredicateNode, SettingGroup, SettingGroupBuilder};
+
+pub fn define_settings(_shared: &SettingGroup) -> SettingGroup {
+    let mut settings = SettingGroupBuilder::new("x86");
+
+    // CPUID.01H:ECX
+    let has_sse3 = settings.add_bool("has_sse3", "SSE3: CPUID.01H:ECX.SSE3[bit 0]", false);
+    let has_ssse3 = settings.add_bool("has_ssse3", "SSSE3: CPUID.01H:ECX.SSSE3[bit 9]", false);
+    let has_sse41 = settings.add_bool("has_sse41", "SSE4.1: CPUID.01H:ECX.SSE4_1[bit 19]", false);
+    let has_sse42 = settings.add_bool("has_sse42", "SSE4.2: CPUID.01H:ECX.SSE4_2[bit 20]", false);
+    let has_popcnt = settings.add_bool("has_popcnt", "POPCNT: CPUID.01H:ECX.POPCNT[bit 23]", false);
+    settings.add_bool("has_avx", "AVX: CPUID.01H:ECX.AVX[bit 28]", false);
+
+    // CPUID.(EAX=07H, ECX=0H):EBX
+    let has_bmi1 = settings.add_bool(
+        "has_bmi1",
+        "BMI1: CPUID.(EAX=07H, ECX=0H):EBX.BMI1[bit 3]",
+        false,
+    );
+    let has_bmi2 = settings.add_bool(
+        "has_bmi2",
+        "BMI2: CPUID.(EAX=07H, ECX=0H):EBX.BMI2[bit 8]",
+        false,
+    );
+
+    // CPUID.EAX=80000001H:ECX
+    let has_lzcnt = settings.add_bool(
+        "has_lzcnt",
+        "LZCNT: CPUID.EAX=80000001H:ECX.LZCNT[bit 5]",
+        false,
+    );
+
+    settings.add_predicate("use_sse41", predicate!(has_sse41));
+    settings.add_predicate("use_sse42", predicate!(has_sse41 && has_sse42));
+    settings.add_predicate("use_popcnt", predicate!(has_popcnt && has_sse42));
+    settings.add_predicate("use_bmi1", predicate!(has_bmi1));
+    settings.add_predicate("use_lznct", predicate!(has_lzcnt));
+
+    settings.add_preset("baseline", preset!());
+    let nehalem = settings.add_preset(
+        "nehalem",
+        preset!(has_sse3 && has_ssse3 && has_sse41 && has_sse42 && has_popcnt),
+    );
+    let haswell = settings.add_preset(
+        "haswell",
+        preset!(nehalem && has_bmi1 && has_bmi2 && has_lzcnt),
+    );
+    let broadwell = settings.add_preset("broadwell", preset!(haswell));
+    let skylake = settings.add_preset("skylake", preset!(broadwell));
+    let cannonlake = settings.add_preset("cannonlake", preset!(skylake));
+    settings.add_preset("icelake", preset!(cannonlake));
+    settings.add_preset(
+        "znver1",
+        preset!(
+            has_sse3
+                && has_ssse3
+                && has_sse41
+                && has_sse42
+                && has_popcnt
+                && has_bmi1
+                && has_bmi2
+                && has_lzcnt
+        ),
+    );
+
+    settings.finish()
+}
+
+fn define_registers(isa: &mut TargetIsaBuilder) {
+    let builder = RegBankBuilder::new("IntRegs", "r")
+        .units(16)
+        .names(vec!["rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi"])
+        .track_pressure(true);
+    let int_regs = isa.add_reg_bank(builder);
+
+    let builder = RegBankBuilder::new("FloatRegs", "xmm")
+        .units(16)
+        .track_pressure(true);
+    let float_regs = isa.add_reg_bank(builder);
+
+    let builder = RegBankBuilder::new("FlagRegs", "")
+        .units(1)
+        .names(vec!["rflags"])
+        .track_pressure(false);
+    let flag_reg = isa.add_reg_bank(builder);
+
+    let builder = RegClassBuilder::new_toplevel("GPR", int_regs);
+    let gpr = isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("FPR", float_regs);
+    let fpr = isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("FLAG", flag_reg);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::subclass_of("GPR8", gpr, 0, 8);
+    let gpr8 = isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::subclass_of("ABCD", gpr8, 0, 4);
+    isa.add_reg_class(builder);
+
+    let builder = RegClassBuilder::subclass_of("FPR8", fpr, 0, 8);
+    isa.add_reg_class(builder);
+}
+
+pub fn define(shared_settings: &SettingGroup) -> TargetIsa {
+    let settings = define_settings(shared_settings);
+
+    let mut isa = TargetIsaBuilder::new("x86", settings);
+
+    define_registers(&mut isa);
+
+    isa.finish()
+}

cranelift/codegen/meta/src/lib.rs

@@ -0,0 +1,13 @@
+#[macro_use]
+mod cdsl;
+
+pub mod error;
+pub mod gen_registers;
+pub mod gen_settings;
+pub mod gen_types;
+pub mod isa;
+
+mod base;
+mod constant_hash;
+mod srcgen;
+mod unique_table;

cranelift/codegen/meta/src/srcgen.rs

@@ -0,0 +1,382 @@
+//! Source code generator.
+//!
+//! The `srcgen` module contains generic helper routines and classes for
+//! generating source code.
+
+use std::cmp;
+use std::collections::{BTreeMap, BTreeSet};
+use std::fs;
+use std::io::Write;
+use std::path;
+
+use crate::error;
+
+static SHIFTWIDTH: usize = 4;
+
+pub struct Formatter {
+    indent: usize,
+    lines: Vec<String>,
+}
+
+impl Formatter {
+    /// Source code formatter class. Used to collect source code to be written
+    /// to a file, and keep track of indentation.
+    pub fn new() -> Self {
+        Self {
+            indent: 0,
+            lines: Vec::new(),
+        }
+    }
+
+    /// Increase current indentation level by one.
+    pub fn indent_push(&mut self) {
+        self.indent += 1;
+    }
+
+    /// Decrease indentation by one level.
+    pub fn indent_pop(&mut self) {
+        assert!(self.indent > 0, "Already at top level indentation");
+        self.indent -= 1;
+    }
+
+    pub fn indent<T, F: FnOnce(&mut Formatter) -> T>(&mut self, f: F) -> T {
+        self.indent_push();
+        let ret = f(self);
+        self.indent_pop();
+        ret
+    }
+
+    /// Get the current whitespace indentation in the form of a String.
+    fn get_indent(&self) -> String {
+        if self.indent == 0 {
+            String::new()
+        } else {
+            format!("{:-1$}", " ", self.indent * SHIFTWIDTH)
+        }
+    }
+
+    /// Get a string containing whitespace outdented one level. Used for
+    /// lines of code that are inside a single indented block.
+    fn _get_outdent(&mut self) -> String {
+        self.indent_push();
+        let s = self.get_indent();
+        self.indent_pop();
+        s
+    }
+
+    /// Add an indented line.
+    pub fn line(&mut self, contents: &str) {
+        let indented_line = format!("{}{}\n", self.get_indent(), contents);
+        self.lines.push(indented_line);
+    }
+
+    /// Emit a line outdented one level.
+    pub fn _outdented_line(&mut self, s: &str) {
+        let new_line = format!("{}{}", self._get_outdent(), s);
+        self.lines.push(new_line);
+    }
+
+    /// Write `self.lines` to a file.
+    pub fn update_file(&self, filename: &str, directory: &str) -> Result<(), error::Error> {
+        #[cfg(target_family = "windows")]
+        let path_str = format!("{}\\{}", directory, filename);
+        #[cfg(not(target_family = "windows"))]
+        let path_str = format!("{}/{}", directory, filename);
+
+        let path = path::Path::new(&path_str);
+        let mut f = fs::File::create(path)?;
+
+        for l in self.lines.iter().map(|l| l.as_bytes()) {
+            f.write_all(l)?;
+        }
+
+        Ok(())
+    }
+
+    /// Add one or more lines after stripping common indentation.
+    pub fn _multi_line(&mut self, s: &str) {
+        parse_multiline(s).into_iter().for_each(|l| self.line(&l));
+    }
+
+    /// Add a comment line.
+    pub fn comment(&mut self, s: &str) {
+        let commented_line = format!("// {}", s);
+        self.line(&commented_line);
+    }
+
+    /// Add a (multi-line) documentation comment.
+    pub fn doc_comment(&mut self, contents: &str) {
+        parse_multiline(contents)
+            .iter()
+            .map(|l| {
+                if l.len() == 0 {
+                    "///".into()
+                } else {
+                    format!("/// {}", l)
+                }
+            })
+            .for_each(|s| self.line(s.as_str()));
+    }
+
+    /// Add a match expression.
+    pub fn add_match(&mut self, m: Match) {
+        self.line(&format!("match {} {{", m.expr));
+        self.indent(|fmt| {
+            for (&(ref fields, ref body), ref names) in m.arms.iter() {
+                // name { fields } | name { fields } => { body }
+                let conditions: Vec<String> = names
+                    .iter()
+                    .map(|name| {
+                        if fields.len() > 0 {
+                            format!("{} {{ {} }}", name, fields.join(", "))
+                        } else {
+                            name.clone()
+                        }
+                    })
+                    .collect();
+                let lhs = conditions.join(" | ");
+                fmt.line(&format!("{} => {{", lhs));
+                fmt.indent(|fmt| {
+                    fmt.line(body);
+                });
+                fmt.line("}");
+            }
+        });
+        self.line("}");
+    }
+}
+
+/// Compute the indentation of s, or None of an empty line.
+fn _indent(s: &str) -> Option<usize> {
+    if s.is_empty() {
+        None
+    } else {
+        let t = s.trim_start();
+        Some(s.len() - t.len())
+    }
+}
+
+/// Given a multi-line string, split it into a sequence of lines after
+/// stripping a common indentation. This is useful for strings defined with
+/// doc strings.
+fn parse_multiline(s: &str) -> Vec<String> {
+    // Convert tabs into spaces.
+    let expanded_tab = format!("{:-1$}", " ", SHIFTWIDTH);
+    let lines: Vec<String> = s.lines().map(|l| l.replace("\t", &expanded_tab)).collect();
+
+    // Determine minimum indentation, ignoring the first line and empty lines.
+    let indent = lines
+        .iter()
+        .skip(1)
+        .filter(|l| !l.trim().is_empty())
+        .map(|l| l.len() - l.trim_start().len())
+        .min();
+
+    // Strip off leading blank lines.
+    let mut lines_iter = lines.iter().skip_while(|l| l.is_empty());
+    let mut trimmed = Vec::with_capacity(lines.len());
+
+    // Remove indentation (first line is special)
+    if let Some(s) = lines_iter.next().map(|l| l.trim()).map(|l| l.to_string()) {
+        trimmed.push(s);
+    }
+
+    // Remove trailing whitespace from other lines.
+    let mut other_lines = if let Some(indent) = indent {
+        // Note that empty lines may have fewer than `indent` chars.
+        lines_iter
+            .map(|l| &l[cmp::min(indent, l.len())..])
+            .map(|l| l.trim_end())
+            .map(|l| l.to_string())
+            .collect::<Vec<_>>()
+    } else {
+        lines_iter
+            .map(|l| l.trim_end())
+            .map(|l| l.to_string())
+            .collect::<Vec<_>>()
+    };
+
+    trimmed.append(&mut other_lines);
+
+    // Strip off trailing blank lines.
+    while let Some(s) = trimmed.pop() {
+        if s.is_empty() {
+            continue;
+        } else {
+            trimmed.push(s);
+            break;
+        }
+    }
+
+    trimmed
+}
+
+/// Match formatting class.
+///
+/// Match objects collect all the information needed to emit a Rust `match`
+/// expression, automatically deduplicating overlapping identical arms.
+///
+/// Note that this class is ignorant of Rust types, and considers two fields
+/// with the same name to be equivalent. BTreeMap/BTreeSet are used to
+/// represent the arms in order to make the order deterministic.
+pub struct Match {
+    expr: String,
+    arms: BTreeMap<(Vec<String>, String), BTreeSet<String>>,
+}
+
+impl Match {
+    /// Create a new match statement on `expr`.
+    pub fn new<T: Into<String>>(expr: T) -> Self {
+        Self {
+            expr: expr.into(),
+            arms: BTreeMap::new(),
+        }
+    }
+
+    /// Add an arm to the Match statement.
+    pub fn arm<T: Into<String>>(&mut self, name: T, fields: Vec<T>, body: T) {
+        // let key = (fields, body);
+        let body = body.into();
+        let fields = fields.into_iter().map(|x| x.into()).collect();
+        let match_arm = self
+            .arms
+            .entry((fields, body))
+            .or_insert_with(BTreeSet::new);
+        match_arm.insert(name.into());
+    }
+}
+
+#[cfg(test)]
+mod srcgen_tests {
+    use super::parse_multiline;
+    use super::Formatter;
+    use super::Match;
+
+    fn from_raw_string<S: Into<String>>(s: S) -> Vec<String> {
+        s.into()
+            .trim()
+            .split("\n")
+            .into_iter()
+            .map(|x| format!("{}\n", x))
+            .collect()
+    }
+
+    #[test]
+    fn adding_arms_works() {
+        let mut m = Match::new("x");
+        m.arm("Orange", vec!["a", "b"], "some body");
+        m.arm("Yellow", vec!["a", "b"], "some body");
+        m.arm("Green", vec!["a", "b"], "different body");
+        m.arm("Blue", vec!["x", "y"], "some body");
+        assert_eq!(m.arms.len(), 3);
+
+        let mut fmt = Formatter::new();
+        fmt.add_match(m);
+
+        let expected_lines = from_raw_string(
+            r#"
+match x {
+    Green { a, b } => {
+        different body
+    }
+    Orange { a, b } | Yellow { a, b } => {
+        some body
+    }
+    Blue { x, y } => {
+        some body
+    }
+}
+        "#,
+        );
+        assert_eq!(fmt.lines, expected_lines);
+    }
+
+    #[test]
+    fn parse_multiline_works() {
+        let input = "\n    hello\n    world\n";
+        let expected = vec!["hello", "world"];
+        let output = parse_multiline(input);
+        assert_eq!(output, expected);
+    }
+
+    #[test]
+    fn formatter_basic_example_works() {
+        let mut fmt = Formatter::new();
+        fmt.line("Hello line 1");
+        fmt.indent_push();
+        fmt.comment("Nested comment");
+        fmt.indent_pop();
+        fmt.line("Back home again");
+        let expected_lines = vec![
+            "Hello line 1\n",
+            "    // Nested comment\n",
+            "Back home again\n",
+        ];
+        assert_eq!(fmt.lines, expected_lines);
+    }
+
+    #[test]
+    fn get_indent_works() {
+        let mut fmt = Formatter::new();
+        let expected_results = vec!["", "    ", "        ", ""];
+
+        let actual_results = Vec::with_capacity(4);
+        (0..3).for_each(|_| {
+            fmt.get_indent();
+            fmt.indent_push();
+        });
+        (0..3).for_each(|_| fmt.indent_pop());
+        fmt.get_indent();
+
+        actual_results
+            .into_iter()
+            .zip(expected_results.into_iter())
+            .for_each(|(actual, expected): (String, &str)| assert_eq!(&actual, expected));
+    }
+
+    #[test]
+    fn fmt_can_add_type_to_lines() {
+        let mut fmt = Formatter::new();
+        fmt.line(&format!("pub const {}: Type = Type({:#x});", "example", 0,));
+        let expected_lines = vec!["pub const example: Type = Type(0x0);\n"];
+        assert_eq!(fmt.lines, expected_lines);
+    }
+
+    #[test]
+    fn fmt_can_add_indented_line() {
+        let mut fmt = Formatter::new();
+        fmt.line("hello");
+        fmt.indent_push();
+        fmt.line("world");
+        let expected_lines = vec!["hello\n", "    world\n"];
+        assert_eq!(fmt.lines, expected_lines);
+    }
+
+    #[test]
+    fn fmt_can_add_doc_comments() {
+        let mut fmt = Formatter::new();
+        fmt.doc_comment("documentation\nis\ngood");
+        let expected_lines = vec!["/// documentation\n", "/// is\n", "/// good\n"];
+        assert_eq!(fmt.lines, expected_lines);
+    }
+
+    #[test]
+    fn fmt_can_add_doc_comments_with_empty_lines() {
+        let mut fmt = Formatter::new();
+        fmt.doc_comment(
+            r#"documentation
+        can be really good.
+
+        If you stick to writing it.
+"#,
+        );
+        let expected_lines = from_raw_string(
+            r#"
+/// documentation
+/// can be really good.
+///
+/// If you stick to writing it."#,
+        );
+        assert_eq!(fmt.lines, expected_lines);
+    }
+}

cranelift/codegen/meta/src/unique_table.rs

@@ -0,0 +1,68 @@
+use std::slice;
+
+/// A table of sequences which tries to avoid common subsequences.
+pub struct UniqueTable<T: PartialEq + Clone> {
+    table: Vec<T>,
+}
+
+impl<T: PartialEq + Clone> UniqueTable<T> {
+    pub fn new() -> Self {
+        Self { table: Vec::new() }
+    }
+    pub fn add(&mut self, values: &Vec<T>) -> usize {
+        if let Some(offset) = find_subsequence(values, &self.table) {
+            offset
+        } else {
+            let offset = self.table.len();
+            self.table.extend((*values).clone());
+            offset
+        }
+    }
+    pub fn len(&self) -> usize {
+        self.table.len()
+    }
+    pub fn iter(&self) -> slice::Iter<T> {
+        self.table.iter()
+    }
+}
+
+/// Try to find the subsequence `sub` in the `whole` sequence. Returns None if
+/// it's not been found, or Some(index) if it has been. Naive implementation
+/// until proven we need something better.
+fn find_subsequence<T: PartialEq>(sub: &Vec<T>, whole: &Vec<T>) -> Option<usize> {
+    assert!(sub.len() > 0);
+    // We want i + sub.len() <= whole.len(), i.e. i < whole.len() + 1 - sub.len().
+    if whole.len() < sub.len() {
+        return None;
+    }
+    let max = whole.len() + 1 - sub.len();
+    for i in 0..max {
+        let mut found: Option<usize> = Some(i);
+        for j in 0..sub.len() {
+            if sub[j] != whole[i + j] {
+                found = None;
+                break;
+            }
+        }
+        if found.is_some() {
+            return found;
+        }
+    }
+    return None;
+}
+
+#[test]
+fn test_find_subsequence() {
+    assert_eq!(find_subsequence(&vec![1], &vec![4]), None);
+    assert_eq!(find_subsequence(&vec![1], &vec![1]), Some(0));
+    assert_eq!(find_subsequence(&vec![1, 2], &vec![1]), None);
+    assert_eq!(find_subsequence(&vec![1, 2], &vec![1, 2]), Some(0));
+    assert_eq!(find_subsequence(&vec![1, 2], &vec![1, 3]), None);
+    assert_eq!(find_subsequence(&vec![1, 2], &vec![0, 1, 2]), Some(1));
+    assert_eq!(find_subsequence(&vec![1, 2], &vec![0, 1, 3, 1]), None);
+    assert_eq!(find_subsequence(&vec![1, 2], &vec![0, 1, 3, 1, 2]), Some(3));
+    assert_eq!(
+        find_subsequence(&vec![1, 1, 3], &vec![1, 1, 1, 3, 3]),
+        Some(1)
+    );
+}