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-rw-r--r--library/compiler-builtins/crates/libm-macros/src/enums.rs171
-rw-r--r--library/compiler-builtins/crates/libm-macros/src/lib.rs504
-rw-r--r--library/compiler-builtins/crates/libm-macros/src/parse.rs296
-rw-r--r--library/compiler-builtins/crates/libm-macros/src/shared.rs590
4 files changed, 1561 insertions, 0 deletions
diff --git a/library/compiler-builtins/crates/libm-macros/src/enums.rs b/library/compiler-builtins/crates/libm-macros/src/enums.rs
new file mode 100644
index 00000000000..b4646f984d4
--- /dev/null
+++ b/library/compiler-builtins/crates/libm-macros/src/enums.rs
@@ -0,0 +1,171 @@
+use heck::ToUpperCamelCase;
+use proc_macro2 as pm2;
+use proc_macro2::{Ident, Span};
+use quote::quote;
+use syn::spanned::Spanned;
+use syn::{Fields, ItemEnum, Variant};
+
+use crate::{ALL_OPERATIONS, base_name};
+
+/// Implement `#[function_enum]`, see documentation in `lib.rs`.
+pub fn function_enum(
+    mut item: ItemEnum,
+    attributes: pm2::TokenStream,
+) -> syn::Result<pm2::TokenStream> {
+    expect_empty_enum(&item)?;
+    let attr_span = attributes.span();
+    let mut attr = attributes.into_iter();
+
+    // Attribute should be the identifier of the `BaseName` enum.
+    let Some(tt) = attr.next() else {
+        return Err(syn::Error::new(attr_span, "expected one attribute"));
+    };
+
+    let pm2::TokenTree::Ident(base_enum) = tt else {
+        return Err(syn::Error::new(tt.span(), "expected an identifier"));
+    };
+
+    if let Some(tt) = attr.next() {
+        return Err(syn::Error::new(
+            tt.span(),
+            "unexpected token after identifier",
+        ));
+    }
+
+    let enum_name = &item.ident;
+    let mut as_str_arms = Vec::new();
+    let mut from_str_arms = Vec::new();
+    let mut base_arms = Vec::new();
+
+    for func in ALL_OPERATIONS.iter() {
+        let fn_name = func.name;
+        let ident = Ident::new(&fn_name.to_upper_camel_case(), Span::call_site());
+        let bname_ident = Ident::new(&base_name(fn_name).to_upper_camel_case(), Span::call_site());
+
+        // Match arm for `fn as_str(self)` matcher
+        as_str_arms.push(quote! { Self::#ident => #fn_name });
+        from_str_arms.push(quote! { #fn_name => Self::#ident });
+
+        // Match arm for `fn base_name(self)` matcher
+        base_arms.push(quote! { Self::#ident => #base_enum::#bname_ident });
+
+        let variant = Variant {
+            attrs: Vec::new(),
+            ident,
+            fields: Fields::Unit,
+            discriminant: None,
+        };
+
+        item.variants.push(variant);
+    }
+
+    let variants = item.variants.iter();
+
+    let res = quote! {
+        // Instantiate the enum
+        #item
+
+        impl #enum_name {
+            /// All variants of this enum.
+            pub const ALL: &[Self] = &[
+                #( Self::#variants, )*
+            ];
+
+            /// The stringified version of this function name.
+            pub const fn as_str(self) -> &'static str {
+                match self {
+                    #( #as_str_arms , )*
+                }
+            }
+
+            /// If `s` is the name of a function, return it.
+            pub fn from_str(s: &str) -> Option<Self> {
+                let ret = match s {
+                    #( #from_str_arms , )*
+                    _ => return None,
+                };
+                Some(ret)
+            }
+
+            /// The base name enum for this function.
+            pub const fn base_name(self) -> #base_enum {
+                match self {
+                    #( #base_arms, )*
+                }
+            }
+
+            /// Return information about this operation.
+            pub fn math_op(self) -> &'static crate::op::MathOpInfo {
+                crate::op::ALL_OPERATIONS.iter().find(|op| op.name == self.as_str()).unwrap()
+            }
+        }
+    };
+
+    Ok(res)
+}
+
+/// Implement `#[base_name_enum]`, see documentation in `lib.rs`.
+pub fn base_name_enum(
+    mut item: ItemEnum,
+    attributes: pm2::TokenStream,
+) -> syn::Result<pm2::TokenStream> {
+    expect_empty_enum(&item)?;
+    if !attributes.is_empty() {
+        let sp = attributes.span();
+        return Err(syn::Error::new(sp.span(), "no attributes expected"));
+    }
+
+    let mut base_names: Vec<_> = ALL_OPERATIONS
+        .iter()
+        .map(|func| base_name(func.name))
+        .collect();
+    base_names.sort_unstable();
+    base_names.dedup();
+
+    let item_name = &item.ident;
+    let mut as_str_arms = Vec::new();
+
+    for base_name in base_names {
+        let ident = Ident::new(&base_name.to_upper_camel_case(), Span::call_site());
+
+        // Match arm for `fn as_str(self)` matcher
+        as_str_arms.push(quote! { Self::#ident => #base_name });
+
+        let variant = Variant {
+            attrs: Vec::new(),
+            ident,
+            fields: Fields::Unit,
+            discriminant: None,
+        };
+
+        item.variants.push(variant);
+    }
+
+    let res = quote! {
+        // Instantiate the enum
+        #item
+
+        impl #item_name {
+            /// The stringified version of this base name.
+            pub const fn as_str(self) -> &'static str {
+                match self {
+                    #( #as_str_arms ),*
+                }
+            }
+        }
+    };
+
+    Ok(res)
+}
+
+/// Verify that an enum is empty, otherwise return an error
+fn expect_empty_enum(item: &ItemEnum) -> syn::Result<()> {
+    if !item.variants.is_empty() {
+        Err(syn::Error::new(
+            item.variants.span(),
+            "expected an empty enum",
+        ))
+    } else {
+        Ok(())
+    }
+}
diff --git a/library/compiler-builtins/crates/libm-macros/src/lib.rs b/library/compiler-builtins/crates/libm-macros/src/lib.rs
new file mode 100644
index 00000000000..482da974ca8
--- /dev/null
+++ b/library/compiler-builtins/crates/libm-macros/src/lib.rs
@@ -0,0 +1,504 @@
+#![feature(let_chains)]
+
+mod enums;
+mod parse;
+mod shared;
+
+use parse::{Invocation, StructuredInput};
+use proc_macro as pm;
+use proc_macro2::{self as pm2, Span};
+use quote::{ToTokens, quote};
+pub(crate) use shared::{ALL_OPERATIONS, FloatTy, MathOpInfo, Ty};
+use syn::spanned::Spanned;
+use syn::visit_mut::VisitMut;
+use syn::{Ident, ItemEnum};
+
+const KNOWN_TYPES: &[&str] = &[
+    "FTy", "CFn", "CArgs", "CRet", "RustFn", "RustArgs", "RustRet", "public",
+];
+
+/// Populate an enum with a variant representing function. Names are in upper camel case.
+///
+/// Applied to an empty enum. Expects one attribute `#[function_enum(BaseName)]` that provides
+/// the name of the `BaseName` enum.
+#[proc_macro_attribute]
+pub fn function_enum(attributes: pm::TokenStream, tokens: pm::TokenStream) -> pm::TokenStream {
+    let item = syn::parse_macro_input!(tokens as ItemEnum);
+    let res = enums::function_enum(item, attributes.into());
+
+    match res {
+        Ok(ts) => ts,
+        Err(e) => e.into_compile_error(),
+    }
+    .into()
+}
+
+/// Create an enum representing all possible base names, with names in upper camel case.
+///
+/// Applied to an empty enum.
+#[proc_macro_attribute]
+pub fn base_name_enum(attributes: pm::TokenStream, tokens: pm::TokenStream) -> pm::TokenStream {
+    let item = syn::parse_macro_input!(tokens as ItemEnum);
+    let res = enums::base_name_enum(item, attributes.into());
+
+    match res {
+        Ok(ts) => ts,
+        Err(e) => e.into_compile_error(),
+    }
+    .into()
+}
+
+/// Do something for each function present in this crate.
+///
+/// Takes a callback macro and invokes it multiple times, once for each function that
+/// this crate exports. This makes it easy to create generic tests, benchmarks, or other checks
+/// and apply it to each symbol.
+///
+/// Additionally, the `extra` and `fn_extra` patterns can make use of magic identifiers:
+///
+/// - `MACRO_FN_NAME`: gets replaced with the name of the function on that invocation.
+/// - `MACRO_FN_NAME_NORMALIZED`: similar to the above, but removes sufixes so e.g. `sinf` becomes
+///   `sin`, `cosf128` becomes `cos`, etc.
+///
+/// Invoke as:
+///
+/// ```
+/// // Macro that is invoked once per function
+/// macro_rules! callback_macro {
+///     (
+///         // Name of that function
+///         fn_name: $fn_name:ident,
+///         // The basic float type for this function (e.g. `f32`, `f64`)
+///         FTy: $FTy:ty,
+///         // Function signature of the C version (e.g. `fn(f32, &mut f32) -> f32`)
+///         CFn: $CFn:ty,
+///         // A tuple representing the C version's arguments (e.g. `(f32, &mut f32)`)
+///         CArgs: $CArgs:ty,
+///         // The C version's return type (e.g. `f32`)
+///         CRet: $CRet:ty,
+///         // Function signature of the Rust version (e.g. `fn(f32) -> (f32, f32)`)
+///         RustFn: $RustFn:ty,
+///         // A tuple representing the Rust version's arguments (e.g. `(f32,)`)
+///         RustArgs: $RustArgs:ty,
+///         // The Rust version's return type (e.g. `(f32, f32)`)
+///         RustRet: $RustRet:ty,
+///         // True if this is part of `libm`'s public API
+///         public: $public:expr,
+///         // Attributes for the current function, if any
+///         attrs: [$($attr:meta),*],
+///         // Extra tokens passed directly (if any)
+///         extra: [$extra:ident],
+///         // Extra function-tokens passed directly (if any)
+///         fn_extra: $fn_extra:expr,
+///     ) => { };
+/// }
+///
+/// // All fields except for `callback` are optional.
+/// libm_macros::for_each_function! {
+///     // The macro to invoke as a callback
+///     callback: callback_macro,
+///     // Which types to include either as a list (`[CFn, RustFn, RustArgs]`) or "all"
+///     emit_types: all,
+///     // Functions to skip, i.e. `callback` shouldn't be called at all for these.
+///     skip: [sin, cos],
+///     // Attributes passed as `attrs` for specific functions. For example, here the invocation
+///     // with `sinf` and that with `cosf` will both get `meta1` and `meta2`, but no others will.
+///     //
+///     // Note that `f16_enabled` and `f128_enabled` will always get emitted regardless of whether
+///     // or not this is specified.
+///     attributes: [
+///         #[meta1]
+///         #[meta2]
+///         [sinf, cosf],
+///     ],
+///     // Any tokens that should be passed directly to all invocations of the callback. This can
+///     // be used to pass local variables or other things the macro needs access to.
+///     extra: [foo],
+///     // Similar to `extra`, but allow providing a pattern for only specific functions. Uses
+///     // a simplified match-like syntax.
+///     fn_extra: match MACRO_FN_NAME {
+///         hypot | hypotf => |x| x.hypot(),
+///         // `ALL_*` magic matchers also work to extract specific types
+///         ALL_F64 => |x| x,
+///         // The default pattern gets applied to everything that did not match
+///         _ => |x| x,
+///     },
+/// }
+/// ```
+#[proc_macro]
+pub fn for_each_function(tokens: pm::TokenStream) -> pm::TokenStream {
+    let input = syn::parse_macro_input!(tokens as Invocation);
+
+    let res = StructuredInput::from_fields(input)
+        .and_then(|mut s_in| validate(&mut s_in).map(|fn_list| (s_in, fn_list)))
+        .and_then(|(s_in, fn_list)| expand(s_in, &fn_list));
+
+    match res {
+        Ok(ts) => ts.into(),
+        Err(e) => e.into_compile_error().into(),
+    }
+}
+
+/// Check for any input that is structurally correct but has other problems.
+///
+/// Returns the list of function names that we should expand for.
+fn validate(input: &mut StructuredInput) -> syn::Result<Vec<&'static MathOpInfo>> {
+    // Replace magic mappers with a list of relevant functions.
+    if let Some(map) = &mut input.fn_extra {
+        for (name, ty) in [
+            ("ALL_F16", FloatTy::F16),
+            ("ALL_F32", FloatTy::F32),
+            ("ALL_F64", FloatTy::F64),
+            ("ALL_F128", FloatTy::F128),
+        ] {
+            let Some(k) = map.keys().find(|key| *key == name) else {
+                continue;
+            };
+
+            let key = k.clone();
+            let val = map.remove(&key).unwrap();
+
+            for op in ALL_OPERATIONS.iter().filter(|op| op.float_ty == ty) {
+                map.insert(Ident::new(op.name, key.span()), val.clone());
+            }
+        }
+    }
+
+    // Collect lists of all functions that are provied as macro inputs in various fields (only,
+    // skip, attributes).
+    let attr_mentions = input
+        .attributes
+        .iter()
+        .flat_map(|map_list| map_list.iter())
+        .flat_map(|attr_map| attr_map.names.iter());
+    let only_mentions = input.only.iter().flat_map(|only_list| only_list.iter());
+    let fn_extra_mentions = input
+        .fn_extra
+        .iter()
+        .flat_map(|v| v.keys())
+        .filter(|name| *name != "_");
+    let all_mentioned_fns = input
+        .skip
+        .iter()
+        .chain(only_mentions)
+        .chain(attr_mentions)
+        .chain(fn_extra_mentions);
+
+    // Make sure that every function mentioned is a real function
+    for mentioned in all_mentioned_fns {
+        if !ALL_OPERATIONS.iter().any(|func| mentioned == func.name) {
+            let e = syn::Error::new(
+                mentioned.span(),
+                format!("unrecognized function name `{mentioned}`"),
+            );
+            return Err(e);
+        }
+    }
+
+    if !input.skip.is_empty() && input.only.is_some() {
+        let e = syn::Error::new(
+            input.only_span.unwrap(),
+            "only one of `skip` or `only` may be specified",
+        );
+        return Err(e);
+    }
+
+    // Construct a list of what we intend to expand
+    let mut fn_list = Vec::new();
+    for func in ALL_OPERATIONS.iter() {
+        let fn_name = func.name;
+        // If we have an `only` list and it does _not_ contain this function name, skip it
+        if input
+            .only
+            .as_ref()
+            .is_some_and(|only| !only.iter().any(|o| o == fn_name))
+        {
+            continue;
+        }
+
+        // If there is a `skip` list that contains this function name, skip it
+        if input.skip.iter().any(|s| s == fn_name) {
+            continue;
+        }
+
+        // Omit f16 and f128 functions if requested
+        if input.skip_f16_f128 && (func.float_ty == FloatTy::F16 || func.float_ty == FloatTy::F128)
+        {
+            continue;
+        }
+
+        // Run everything else
+        fn_list.push(func);
+    }
+
+    // Types that the user would like us to provide in the macro
+    let mut add_all_types = false;
+    for ty in &input.emit_types {
+        let ty_name = ty.to_string();
+        if ty_name == "all" {
+            add_all_types = true;
+            continue;
+        }
+
+        // Check that all requested types are valid
+        if !KNOWN_TYPES.contains(&ty_name.as_str()) {
+            let e = syn::Error::new(
+                ty_name.span(),
+                format!("unrecognized type identifier `{ty_name}`"),
+            );
+            return Err(e);
+        }
+    }
+
+    if add_all_types {
+        // Ensure that if `all` was specified that nothing else was
+        if input.emit_types.len() > 1 {
+            let e = syn::Error::new(
+                input.emit_types_span.unwrap(),
+                "if `all` is specified, no other type identifiers may be given",
+            );
+            return Err(e);
+        }
+
+        // ...and then add all types
+        input.emit_types.clear();
+        for ty in KNOWN_TYPES {
+            let ident = Ident::new(ty, Span::call_site());
+            input.emit_types.push(ident);
+        }
+    }
+
+    if let Some(map) = &input.fn_extra
+        && !map.keys().any(|key| key == "_")
+    {
+        // No default provided; make sure every expected function is covered
+        let mut fns_not_covered = Vec::new();
+        for func in &fn_list {
+            if !map.keys().any(|key| key == func.name) {
+                // `name` was not mentioned in the `match` statement
+                fns_not_covered.push(func);
+            }
+        }
+
+        if !fns_not_covered.is_empty() {
+            let e = syn::Error::new(
+                input.fn_extra_span.unwrap(),
+                format!(
+                    "`fn_extra`: no default `_` pattern specified and the following \
+                     patterns are not covered: {fns_not_covered:#?}"
+                ),
+            );
+            return Err(e);
+        }
+    };
+
+    Ok(fn_list)
+}
+
+/// Expand our structured macro input into invocations of the callback macro.
+fn expand(input: StructuredInput, fn_list: &[&MathOpInfo]) -> syn::Result<pm2::TokenStream> {
+    let mut out = pm2::TokenStream::new();
+    let default_ident = Ident::new("_", Span::call_site());
+    let callback = input.callback;
+
+    for func in fn_list {
+        let fn_name = Ident::new(func.name, Span::call_site());
+
+        // Prepare attributes in an `attrs: ...` field
+        let mut meta_fields = Vec::new();
+        if let Some(attrs) = &input.attributes {
+            let meta_iter = attrs
+                .iter()
+                .filter(|map| map.names.contains(&fn_name))
+                .flat_map(|map| &map.meta)
+                .map(|v| v.into_token_stream());
+
+            meta_fields.extend(meta_iter);
+        }
+
+        // Always emit f16 and f128 meta so this doesn't need to be repeated everywhere
+        if func.rust_sig.args.contains(&Ty::F16) || func.rust_sig.returns.contains(&Ty::F16) {
+            let ts = quote! { cfg(f16_enabled) };
+            meta_fields.push(ts);
+        }
+        if func.rust_sig.args.contains(&Ty::F128) || func.rust_sig.returns.contains(&Ty::F128) {
+            let ts = quote! { cfg(f128_enabled) };
+            meta_fields.push(ts);
+        }
+
+        let meta_field = quote! { attrs: [ #( #meta_fields ),* ], };
+
+        // Prepare extra in an `extra: ...` field, running the replacer
+        let extra_field = match input.extra.clone() {
+            Some(mut extra) => {
+                let mut v = MacroReplace::new(func.name);
+                v.visit_expr_mut(&mut extra);
+                v.finish()?;
+
+                quote! { extra: #extra, }
+            }
+            None => pm2::TokenStream::new(),
+        };
+
+        // Prepare function-specific extra in a `fn_extra: ...` field, running the replacer
+        let fn_extra_field = match input.fn_extra {
+            Some(ref map) => {
+                let mut fn_extra = map
+                    .get(&fn_name)
+                    .or_else(|| map.get(&default_ident))
+                    .unwrap()
+                    .clone();
+
+                let mut v = MacroReplace::new(func.name);
+                v.visit_expr_mut(&mut fn_extra);
+                v.finish()?;
+
+                quote! { fn_extra: #fn_extra, }
+            }
+            None => pm2::TokenStream::new(),
+        };
+
+        let base_fty = func.float_ty;
+        let c_args = &func.c_sig.args;
+        let c_ret = &func.c_sig.returns;
+        let rust_args = &func.rust_sig.args;
+        let rust_ret = &func.rust_sig.returns;
+        let public = func.public;
+
+        let mut ty_fields = Vec::new();
+        for ty in &input.emit_types {
+            let field = match ty.to_string().as_str() {
+                "FTy" => quote! { FTy: #base_fty, },
+                "CFn" => quote! { CFn: fn( #(#c_args),* ,) -> ( #(#c_ret),* ), },
+                "CArgs" => quote! { CArgs: ( #(#c_args),* ,), },
+                "CRet" => quote! { CRet: ( #(#c_ret),* ), },
+                "RustFn" => quote! { RustFn: fn( #(#rust_args),* ,) -> ( #(#rust_ret),* ), },
+                "RustArgs" => quote! { RustArgs: ( #(#rust_args),* ,), },
+                "RustRet" => quote! { RustRet: ( #(#rust_ret),* ), },
+                "public" => quote! { public: #public, },
+                _ => unreachable!("checked in validation"),
+            };
+            ty_fields.push(field);
+        }
+
+        let new = quote! {
+            #callback! {
+                fn_name: #fn_name,
+                #( #ty_fields )*
+                #meta_field
+                #extra_field
+                #fn_extra_field
+            }
+        };
+
+        out.extend(new);
+    }
+
+    Ok(out)
+}
+
+/// Visitor to replace "magic" identifiers that we allow: `MACRO_FN_NAME` and
+/// `MACRO_FN_NAME_NORMALIZED`.
+struct MacroReplace {
+    fn_name: &'static str,
+    /// Remove the trailing `f` or `f128` to make
+    norm_name: String,
+    error: Option<syn::Error>,
+}
+
+impl MacroReplace {
+    fn new(name: &'static str) -> Self {
+        let norm_name = base_name(name);
+        Self {
+            fn_name: name,
+            norm_name: norm_name.to_owned(),
+            error: None,
+        }
+    }
+
+    fn finish(self) -> syn::Result<()> {
+        match self.error {
+            Some(e) => Err(e),
+            None => Ok(()),
+        }
+    }
+
+    fn visit_ident_inner(&mut self, i: &mut Ident) {
+        let s = i.to_string();
+        if !s.starts_with("MACRO") || self.error.is_some() {
+            return;
+        }
+
+        match s.as_str() {
+            "MACRO_FN_NAME" => *i = Ident::new(self.fn_name, i.span()),
+            "MACRO_FN_NAME_NORMALIZED" => *i = Ident::new(&self.norm_name, i.span()),
+            _ => {
+                self.error = Some(syn::Error::new(
+                    i.span(),
+                    format!("unrecognized meta expression `{s}`"),
+                ));
+            }
+        }
+    }
+}
+
+impl VisitMut for MacroReplace {
+    fn visit_ident_mut(&mut self, i: &mut Ident) {
+        self.visit_ident_inner(i);
+        syn::visit_mut::visit_ident_mut(self, i);
+    }
+}
+
+/// Return the unsuffixed version of a function name; e.g. `abs` and `absf` both return `abs`,
+/// `lgamma_r` and `lgammaf_r` both return `lgamma_r`.
+fn base_name(name: &str) -> &str {
+    let known_mappings = &[
+        ("erff", "erf"),
+        ("erf", "erf"),
+        ("lgammaf_r", "lgamma_r"),
+        ("modff", "modf"),
+        ("modf", "modf"),
+    ];
+
+    match known_mappings.iter().find(|known| known.0 == name) {
+        Some(found) => found.1,
+        None => name
+            .strip_suffix("f")
+            .or_else(|| name.strip_suffix("f16"))
+            .or_else(|| name.strip_suffix("f128"))
+            .unwrap_or(name),
+    }
+}
+
+impl ToTokens for Ty {
+    fn to_tokens(&self, tokens: &mut pm2::TokenStream) {
+        let ts = match self {
+            Ty::F16 => quote! { f16 },
+            Ty::F32 => quote! { f32 },
+            Ty::F64 => quote! { f64 },
+            Ty::F128 => quote! { f128 },
+            Ty::I32 => quote! { i32 },
+            Ty::CInt => quote! { ::core::ffi::c_int },
+            Ty::MutF16 => quote! { &'a mut f16 },
+            Ty::MutF32 => quote! { &'a mut f32 },
+            Ty::MutF64 => quote! { &'a mut f64 },
+            Ty::MutF128 => quote! { &'a mut f128 },
+            Ty::MutI32 => quote! { &'a mut i32 },
+            Ty::MutCInt => quote! { &'a mut core::ffi::c_int },
+        };
+
+        tokens.extend(ts);
+    }
+}
+impl ToTokens for FloatTy {
+    fn to_tokens(&self, tokens: &mut pm2::TokenStream) {
+        let ts = match self {
+            FloatTy::F16 => quote! { f16 },
+            FloatTy::F32 => quote! { f32 },
+            FloatTy::F64 => quote! { f64 },
+            FloatTy::F128 => quote! { f128 },
+        };
+
+        tokens.extend(ts);
+    }
+}
diff --git a/library/compiler-builtins/crates/libm-macros/src/parse.rs b/library/compiler-builtins/crates/libm-macros/src/parse.rs
new file mode 100644
index 00000000000..4876f3ef726
--- /dev/null
+++ b/library/compiler-builtins/crates/libm-macros/src/parse.rs
@@ -0,0 +1,296 @@
+use std::collections::BTreeMap;
+
+use proc_macro2::Span;
+use quote::ToTokens;
+use syn::parse::{Parse, ParseStream, Parser};
+use syn::punctuated::Punctuated;
+use syn::spanned::Spanned;
+use syn::token::{self, Comma};
+use syn::{Arm, Attribute, Expr, ExprMatch, Ident, LitBool, Meta, Token, bracketed};
+
+/// The input to our macro; just a list of `field: value` items.
+#[derive(Debug)]
+pub struct Invocation {
+    fields: Punctuated<Mapping, Comma>,
+}
+
+impl Parse for Invocation {
+    fn parse(input: ParseStream) -> syn::Result<Self> {
+        Ok(Self {
+            fields: input.parse_terminated(Mapping::parse, Token![,])?,
+        })
+    }
+}
+
+/// A `key: expression` mapping with nothing else. Basically a simplified `syn::Field`.
+#[derive(Debug)]
+struct Mapping {
+    name: Ident,
+    _sep: Token![:],
+    expr: Expr,
+}
+
+impl Parse for Mapping {
+    fn parse(input: ParseStream) -> syn::Result<Self> {
+        Ok(Self {
+            name: input.parse()?,
+            _sep: input.parse()?,
+            expr: input.parse()?,
+        })
+    }
+}
+
+/// The input provided to our proc macro, after parsing into the form we expect.
+#[derive(Debug)]
+pub struct StructuredInput {
+    /// Macro to invoke once per function
+    pub callback: Ident,
+    /// Whether or not to provide `CFn` `CArgs` `RustFn` etc. This is really only needed
+    /// once for crate to set up the main trait.
+    pub emit_types: Vec<Ident>,
+    /// Skip these functions
+    pub skip: Vec<Ident>,
+    /// If true, omit f16 and f128 functions that aren't present in other libraries.
+    pub skip_f16_f128: bool,
+    /// Invoke only for these functions
+    pub only: Option<Vec<Ident>>,
+    /// Attributes that get applied to specific functions
+    pub attributes: Option<Vec<AttributeMap>>,
+    /// Extra expressions to pass to all invocations of the macro
+    pub extra: Option<Expr>,
+    /// Per-function extra expressions to pass to the macro
+    pub fn_extra: Option<BTreeMap<Ident, Expr>>,
+    // For diagnostics
+    pub emit_types_span: Option<Span>,
+    pub only_span: Option<Span>,
+    pub fn_extra_span: Option<Span>,
+}
+
+impl StructuredInput {
+    pub fn from_fields(input: Invocation) -> syn::Result<Self> {
+        let mut map: Vec<_> = input.fields.into_iter().collect();
+        let cb_expr = expect_field(&mut map, "callback")?;
+        let emit_types_expr = expect_field(&mut map, "emit_types").ok();
+        let skip_expr = expect_field(&mut map, "skip").ok();
+        let skip_f16_f128 = expect_field(&mut map, "skip_f16_f128").ok();
+        let only_expr = expect_field(&mut map, "only").ok();
+        let attr_expr = expect_field(&mut map, "attributes").ok();
+        let extra = expect_field(&mut map, "extra").ok();
+        let fn_extra = expect_field(&mut map, "fn_extra").ok();
+
+        if !map.is_empty() {
+            Err(syn::Error::new(
+                map.first().unwrap().name.span(),
+                format!("unexpected fields {map:?}"),
+            ))?;
+        }
+
+        let emit_types_span = emit_types_expr.as_ref().map(|expr| expr.span());
+        let emit_types = match emit_types_expr {
+            Some(expr) => Parser::parse2(parse_ident_or_array, expr.into_token_stream())?,
+            None => Vec::new(),
+        };
+
+        let skip = match skip_expr {
+            Some(expr) => Parser::parse2(parse_ident_array, expr.into_token_stream())?,
+            None => Vec::new(),
+        };
+
+        let skip_f16_f128 = match skip_f16_f128 {
+            Some(expr) => expect_litbool(expr)?.value,
+            None => false,
+        };
+
+        let only_span = only_expr.as_ref().map(|expr| expr.span());
+        let only = match only_expr {
+            Some(expr) => Some(Parser::parse2(parse_ident_array, expr.into_token_stream())?),
+            None => None,
+        };
+
+        let attributes = match attr_expr {
+            Some(expr) => {
+                let mut attributes = Vec::new();
+                let attr_exprs = Parser::parse2(parse_expr_array, expr.into_token_stream())?;
+
+                for attr in attr_exprs {
+                    attributes.push(syn::parse2(attr.into_token_stream())?);
+                }
+                Some(attributes)
+            }
+            None => None,
+        };
+
+        let fn_extra_span = fn_extra.as_ref().map(|expr| expr.span());
+        let fn_extra = match fn_extra {
+            Some(expr) => Some(extract_fn_extra_field(expr)?),
+            None => None,
+        };
+
+        Ok(Self {
+            callback: expect_ident(cb_expr)?,
+            emit_types,
+            skip,
+            skip_f16_f128,
+            only,
+            only_span,
+            attributes,
+            extra,
+            fn_extra,
+            fn_extra_span,
+            emit_types_span,
+        })
+    }
+}
+
+fn extract_fn_extra_field(expr: Expr) -> syn::Result<BTreeMap<Ident, Expr>> {
+    let Expr::Match(mexpr) = expr else {
+        let e = syn::Error::new(expr.span(), "`fn_extra` expects a match expression");
+        return Err(e);
+    };
+
+    let ExprMatch {
+        attrs,
+        match_token: _,
+        expr,
+        brace_token: _,
+        arms,
+    } = mexpr;
+
+    expect_empty_attrs(&attrs)?;
+
+    let match_on = expect_ident(*expr)?;
+    if match_on != "MACRO_FN_NAME" {
+        let e = syn::Error::new(match_on.span(), "only allowed to match on `MACRO_FN_NAME`");
+        return Err(e);
+    }
+
+    let mut res = BTreeMap::new();
+
+    for arm in arms {
+        let Arm {
+            attrs,
+            pat,
+            guard,
+            fat_arrow_token: _,
+            body,
+            comma: _,
+        } = arm;
+
+        expect_empty_attrs(&attrs)?;
+
+        let keys = match pat {
+            syn::Pat::Wild(w) => vec![Ident::new("_", w.span())],
+            _ => Parser::parse2(parse_ident_pat, pat.into_token_stream())?,
+        };
+
+        if let Some(guard) = guard {
+            let e = syn::Error::new(guard.0.span(), "no guards allowed in this position");
+            return Err(e);
+        }
+
+        for key in keys {
+            let inserted = res.insert(key.clone(), *body.clone());
+            if inserted.is_some() {
+                let e = syn::Error::new(key.span(), format!("key `{key}` specified twice"));
+                return Err(e);
+            }
+        }
+    }
+
+    Ok(res)
+}
+
+fn expect_empty_attrs(attrs: &[Attribute]) -> syn::Result<()> {
+    if attrs.is_empty() {
+        return Ok(());
+    }
+
+    let e = syn::Error::new(
+        attrs.first().unwrap().span(),
+        "no attributes allowed in this position",
+    );
+    Err(e)
+}
+
+/// Extract a named field from a map, raising an error if it doesn't exist.
+fn expect_field(v: &mut Vec<Mapping>, name: &str) -> syn::Result<Expr> {
+    let pos = v.iter().position(|v| v.name == name).ok_or_else(|| {
+        syn::Error::new(
+            Span::call_site(),
+            format!("missing expected field `{name}`"),
+        )
+    })?;
+
+    Ok(v.remove(pos).expr)
+}
+
+/// Coerce an expression into a simple identifier.
+fn expect_ident(expr: Expr) -> syn::Result<Ident> {
+    syn::parse2(expr.into_token_stream())
+}
+
+/// Coerce an expression into a simple keyword.
+fn expect_litbool(expr: Expr) -> syn::Result<LitBool> {
+    syn::parse2(expr.into_token_stream())
+}
+
+/// Parse either a single identifier (`foo`) or an array of identifiers (`[foo, bar, baz]`).
+fn parse_ident_or_array(input: ParseStream) -> syn::Result<Vec<Ident>> {
+    if !input.peek(token::Bracket) {
+        return Ok(vec![input.parse()?]);
+    }
+
+    parse_ident_array(input)
+}
+
+/// Parse an array of expressions.
+fn parse_expr_array(input: ParseStream) -> syn::Result<Vec<Expr>> {
+    let content;
+    let _ = bracketed!(content in input);
+    let fields = content.parse_terminated(Expr::parse, Token![,])?;
+    Ok(fields.into_iter().collect())
+}
+
+/// Parse an array of idents, e.g. `[foo, bar, baz]`.
+fn parse_ident_array(input: ParseStream) -> syn::Result<Vec<Ident>> {
+    let content;
+    let _ = bracketed!(content in input);
+    let fields = content.parse_terminated(Ident::parse, Token![,])?;
+    Ok(fields.into_iter().collect())
+}
+
+/// Parse an pattern of idents, specifically `(foo | bar | baz)`.
+fn parse_ident_pat(input: ParseStream) -> syn::Result<Vec<Ident>> {
+    if !input.peek2(Token![|]) {
+        return Ok(vec![input.parse()?]);
+    }
+
+    let fields = Punctuated::<Ident, Token![|]>::parse_separated_nonempty(input)?;
+    Ok(fields.into_iter().collect())
+}
+
+/// A mapping of attributes to identifiers (just a simplified `Expr`).
+///
+/// Expressed as:
+///
+/// ```ignore
+/// #[meta1]
+/// #[meta2]
+/// [foo, bar, baz]
+/// ```
+#[derive(Debug)]
+pub struct AttributeMap {
+    pub meta: Vec<Meta>,
+    pub names: Vec<Ident>,
+}
+
+impl Parse for AttributeMap {
+    fn parse(input: ParseStream) -> syn::Result<Self> {
+        let attrs = input.call(Attribute::parse_outer)?;
+
+        Ok(Self {
+            meta: attrs.into_iter().map(|a| a.meta).collect(),
+            names: parse_ident_array(input)?,
+        })
+    }
+}
diff --git a/library/compiler-builtins/crates/libm-macros/src/shared.rs b/library/compiler-builtins/crates/libm-macros/src/shared.rs
new file mode 100644
index 00000000000..1cefe4e8c7e
--- /dev/null
+++ b/library/compiler-builtins/crates/libm-macros/src/shared.rs
@@ -0,0 +1,590 @@
+/* List of all functions that is shared between `libm-macros` and `libm-test`. */
+
+use std::fmt;
+use std::sync::LazyLock;
+
+struct NestedOp {
+    float_ty: FloatTy,
+    rust_sig: Signature,
+    c_sig: Option<Signature>,
+    fn_list: &'static [&'static str],
+    public: bool,
+}
+
+/// We need a flat list to work with most of the time, but define things as a more convenient
+/// nested list.
+const ALL_OPERATIONS_NESTED: &[NestedOp] = &[
+    NestedOp {
+        // `fn(f16) -> f16`
+        float_ty: FloatTy::F16,
+        rust_sig: Signature {
+            args: &[Ty::F16],
+            returns: &[Ty::F16],
+        },
+        c_sig: None,
+        fn_list: &[
+            "ceilf16",
+            "fabsf16",
+            "floorf16",
+            "rintf16",
+            "roundevenf16",
+            "roundf16",
+            "sqrtf16",
+            "truncf16",
+        ],
+        public: true,
+    },
+    NestedOp {
+        // `fn(f32) -> f32`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32],
+            returns: &[Ty::F32],
+        },
+        c_sig: None,
+        fn_list: &[
+            "acosf",
+            "acoshf",
+            "asinf",
+            "asinhf",
+            "atanf",
+            "atanhf",
+            "cbrtf",
+            "ceilf",
+            "cosf",
+            "coshf",
+            "erfcf",
+            "erff",
+            "exp10f",
+            "exp2f",
+            "expf",
+            "expm1f",
+            "fabsf",
+            "floorf",
+            "j0f",
+            "j1f",
+            "lgammaf",
+            "log10f",
+            "log1pf",
+            "log2f",
+            "logf",
+            "rintf",
+            "roundevenf",
+            "roundf",
+            "sinf",
+            "sinhf",
+            "sqrtf",
+            "tanf",
+            "tanhf",
+            "tgammaf",
+            "truncf",
+            "y0f",
+            "y1f",
+        ],
+        public: true,
+    },
+    NestedOp {
+        // `(f64) -> f64`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64],
+            returns: &[Ty::F64],
+        },
+        c_sig: None,
+        fn_list: &[
+            "acos",
+            "acosh",
+            "asin",
+            "asinh",
+            "atan",
+            "atanh",
+            "cbrt",
+            "ceil",
+            "cos",
+            "cosh",
+            "erf",
+            "erfc",
+            "exp",
+            "exp10",
+            "exp2",
+            "expm1",
+            "fabs",
+            "floor",
+            "j0",
+            "j1",
+            "lgamma",
+            "log",
+            "log10",
+            "log1p",
+            "log2",
+            "rint",
+            "round",
+            "roundeven",
+            "sin",
+            "sinh",
+            "sqrt",
+            "tan",
+            "tanh",
+            "tgamma",
+            "trunc",
+            "y0",
+            "y1",
+        ],
+        public: true,
+    },
+    NestedOp {
+        // `fn(f128) -> f128`
+        float_ty: FloatTy::F128,
+        rust_sig: Signature {
+            args: &[Ty::F128],
+            returns: &[Ty::F128],
+        },
+        c_sig: None,
+        fn_list: &[
+            "ceilf128",
+            "fabsf128",
+            "floorf128",
+            "rintf128",
+            "roundevenf128",
+            "roundf128",
+            "sqrtf128",
+            "truncf128",
+        ],
+        public: true,
+    },
+    NestedOp {
+        // `(f16, f16) -> f16`
+        float_ty: FloatTy::F16,
+        rust_sig: Signature {
+            args: &[Ty::F16, Ty::F16],
+            returns: &[Ty::F16],
+        },
+        c_sig: None,
+        fn_list: &[
+            "copysignf16",
+            "fdimf16",
+            "fmaxf16",
+            "fmaximum_numf16",
+            "fmaximumf16",
+            "fminf16",
+            "fminimum_numf16",
+            "fminimumf16",
+            "fmodf16",
+        ],
+        public: true,
+    },
+    NestedOp {
+        // `(f32, f32) -> f32`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32, Ty::F32],
+            returns: &[Ty::F32],
+        },
+        c_sig: None,
+        fn_list: &[
+            "atan2f",
+            "copysignf",
+            "fdimf",
+            "fmaxf",
+            "fmaximum_numf",
+            "fmaximumf",
+            "fminf",
+            "fminimum_numf",
+            "fminimumf",
+            "fmodf",
+            "hypotf",
+            "nextafterf",
+            "powf",
+            "remainderf",
+        ],
+        public: true,
+    },
+    NestedOp {
+        // `(f64, f64) -> f64`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64, Ty::F64],
+            returns: &[Ty::F64],
+        },
+        c_sig: None,
+        fn_list: &[
+            "atan2",
+            "copysign",
+            "fdim",
+            "fmax",
+            "fmaximum",
+            "fmaximum_num",
+            "fmin",
+            "fminimum",
+            "fminimum_num",
+            "fmod",
+            "hypot",
+            "nextafter",
+            "pow",
+            "remainder",
+        ],
+        public: true,
+    },
+    NestedOp {
+        // `(f128, f128) -> f128`
+        float_ty: FloatTy::F128,
+        rust_sig: Signature {
+            args: &[Ty::F128, Ty::F128],
+            returns: &[Ty::F128],
+        },
+        c_sig: None,
+        fn_list: &[
+            "copysignf128",
+            "fdimf128",
+            "fmaxf128",
+            "fmaximum_numf128",
+            "fmaximumf128",
+            "fminf128",
+            "fminimum_numf128",
+            "fminimumf128",
+            "fmodf128",
+        ],
+        public: true,
+    },
+    NestedOp {
+        // `(f32, f32, f32) -> f32`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32, Ty::F32, Ty::F32],
+            returns: &[Ty::F32],
+        },
+        c_sig: None,
+        fn_list: &["fmaf"],
+        public: true,
+    },
+    NestedOp {
+        // `(f64, f64, f64) -> f64`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64, Ty::F64, Ty::F64],
+            returns: &[Ty::F64],
+        },
+        c_sig: None,
+        fn_list: &["fma"],
+        public: true,
+    },
+    NestedOp {
+        // `(f128, f128, f128) -> f128`
+        float_ty: FloatTy::F128,
+        rust_sig: Signature {
+            args: &[Ty::F128, Ty::F128, Ty::F128],
+            returns: &[Ty::F128],
+        },
+        c_sig: None,
+        fn_list: &["fmaf128"],
+        public: true,
+    },
+    NestedOp {
+        // `(f32) -> i32`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32],
+            returns: &[Ty::I32],
+        },
+        c_sig: None,
+        fn_list: &["ilogbf"],
+        public: true,
+    },
+    NestedOp {
+        // `(f64) -> i32`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64],
+            returns: &[Ty::I32],
+        },
+        c_sig: None,
+        fn_list: &["ilogb"],
+        public: true,
+    },
+    NestedOp {
+        // `(i32, f32) -> f32`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::I32, Ty::F32],
+            returns: &[Ty::F32],
+        },
+        c_sig: None,
+        fn_list: &["jnf", "ynf"],
+        public: true,
+    },
+    NestedOp {
+        // `(i32, f64) -> f64`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::I32, Ty::F64],
+            returns: &[Ty::F64],
+        },
+        c_sig: None,
+        fn_list: &["jn", "yn"],
+        public: true,
+    },
+    NestedOp {
+        // `(f16, i32) -> f16`
+        float_ty: FloatTy::F16,
+        rust_sig: Signature {
+            args: &[Ty::F16, Ty::I32],
+            returns: &[Ty::F16],
+        },
+        c_sig: None,
+        fn_list: &["ldexpf16", "scalbnf16"],
+        public: true,
+    },
+    NestedOp {
+        // `(f32, i32) -> f32`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32, Ty::I32],
+            returns: &[Ty::F32],
+        },
+        c_sig: None,
+        fn_list: &["ldexpf", "scalbnf"],
+        public: true,
+    },
+    NestedOp {
+        // `(f64, i64) -> f64`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64, Ty::I32],
+            returns: &[Ty::F64],
+        },
+        c_sig: None,
+        fn_list: &["ldexp", "scalbn"],
+        public: true,
+    },
+    NestedOp {
+        // `(f128, i32) -> f128`
+        float_ty: FloatTy::F128,
+        rust_sig: Signature {
+            args: &[Ty::F128, Ty::I32],
+            returns: &[Ty::F128],
+        },
+        c_sig: None,
+        fn_list: &["ldexpf128", "scalbnf128"],
+        public: true,
+    },
+    NestedOp {
+        // `(f32, &mut f32) -> f32` as `(f32) -> (f32, f32)`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32],
+            returns: &[Ty::F32, Ty::F32],
+        },
+        c_sig: Some(Signature {
+            args: &[Ty::F32, Ty::MutF32],
+            returns: &[Ty::F32],
+        }),
+        fn_list: &["modff"],
+        public: true,
+    },
+    NestedOp {
+        // `(f64, &mut f64) -> f64` as  `(f64) -> (f64, f64)`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64],
+            returns: &[Ty::F64, Ty::F64],
+        },
+        c_sig: Some(Signature {
+            args: &[Ty::F64, Ty::MutF64],
+            returns: &[Ty::F64],
+        }),
+        fn_list: &["modf"],
+        public: true,
+    },
+    NestedOp {
+        // `(f32, &mut c_int) -> f32` as `(f32) -> (f32, i32)`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32],
+            returns: &[Ty::F32, Ty::I32],
+        },
+        c_sig: Some(Signature {
+            args: &[Ty::F32, Ty::MutCInt],
+            returns: &[Ty::F32],
+        }),
+        fn_list: &["frexpf", "lgammaf_r"],
+        public: true,
+    },
+    NestedOp {
+        // `(f64, &mut c_int) -> f64` as `(f64) -> (f64, i32)`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64],
+            returns: &[Ty::F64, Ty::I32],
+        },
+        c_sig: Some(Signature {
+            args: &[Ty::F64, Ty::MutCInt],
+            returns: &[Ty::F64],
+        }),
+        fn_list: &["frexp", "lgamma_r"],
+        public: true,
+    },
+    NestedOp {
+        // `(f32, f32, &mut c_int) -> f32` as `(f32, f32) -> (f32, i32)`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32, Ty::F32],
+            returns: &[Ty::F32, Ty::I32],
+        },
+        c_sig: Some(Signature {
+            args: &[Ty::F32, Ty::F32, Ty::MutCInt],
+            returns: &[Ty::F32],
+        }),
+        fn_list: &["remquof"],
+        public: true,
+    },
+    NestedOp {
+        // `(f64, f64, &mut c_int) -> f64` as `(f64, f64) -> (f64, i32)`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64, Ty::F64],
+            returns: &[Ty::F64, Ty::I32],
+        },
+        c_sig: Some(Signature {
+            args: &[Ty::F64, Ty::F64, Ty::MutCInt],
+            returns: &[Ty::F64],
+        }),
+        fn_list: &["remquo"],
+        public: true,
+    },
+    NestedOp {
+        // `(f32, &mut f32, &mut f32)` as `(f32) -> (f32, f32)`
+        float_ty: FloatTy::F32,
+        rust_sig: Signature {
+            args: &[Ty::F32],
+            returns: &[Ty::F32, Ty::F32],
+        },
+        c_sig: Some(Signature {
+            args: &[Ty::F32, Ty::MutF32, Ty::MutF32],
+            returns: &[],
+        }),
+        fn_list: &["sincosf"],
+        public: true,
+    },
+    NestedOp {
+        // `(f64, &mut f64, &mut f64)` as `(f64) -> (f64, f64)`
+        float_ty: FloatTy::F64,
+        rust_sig: Signature {
+            args: &[Ty::F64],
+            returns: &[Ty::F64, Ty::F64],
+        },
+        c_sig: Some(Signature {
+            args: &[Ty::F64, Ty::MutF64, Ty::MutF64],
+            returns: &[],
+        }),
+        fn_list: &["sincos"],
+        public: true,
+    },
+];
+
+/// A type used in a function signature.
+#[allow(dead_code)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum Ty {
+    F16,
+    F32,
+    F64,
+    F128,
+    I32,
+    CInt,
+    MutF16,
+    MutF32,
+    MutF64,
+    MutF128,
+    MutI32,
+    MutCInt,
+}
+
+/// A subset of [`Ty`] representing only floats.
+#[allow(dead_code)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum FloatTy {
+    F16,
+    F32,
+    F64,
+    F128,
+}
+
+impl fmt::Display for Ty {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let s = match self {
+            Ty::F16 => "f16",
+            Ty::F32 => "f32",
+            Ty::F64 => "f64",
+            Ty::F128 => "f128",
+            Ty::I32 => "i32",
+            Ty::CInt => "::core::ffi::c_int",
+            Ty::MutF16 => "&mut f16",
+            Ty::MutF32 => "&mut f32",
+            Ty::MutF64 => "&mut f64",
+            Ty::MutF128 => "&mut f128",
+            Ty::MutI32 => "&mut i32",
+            Ty::MutCInt => "&mut ::core::ffi::c_int",
+        };
+        f.write_str(s)
+    }
+}
+
+impl fmt::Display for FloatTy {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let s = match self {
+            FloatTy::F16 => "f16",
+            FloatTy::F32 => "f32",
+            FloatTy::F64 => "f64",
+            FloatTy::F128 => "f128",
+        };
+        f.write_str(s)
+    }
+}
+
+/// Representation of e.g. `(f32, f32) -> f32`
+#[derive(Debug, Clone)]
+pub struct Signature {
+    pub args: &'static [Ty],
+    pub returns: &'static [Ty],
+}
+
+/// Combined information about a function implementation.
+#[derive(Debug, Clone)]
+pub struct MathOpInfo {
+    pub name: &'static str,
+    pub float_ty: FloatTy,
+    /// Function signature for C implementations
+    pub c_sig: Signature,
+    /// Function signature for Rust implementations
+    pub rust_sig: Signature,
+    /// True if part of libm's public API
+    pub public: bool,
+}
+
+/// A flat representation of `ALL_FUNCTIONS`.
+pub static ALL_OPERATIONS: LazyLock<Vec<MathOpInfo>> = LazyLock::new(|| {
+    let mut ret = Vec::new();
+
+    for op in ALL_OPERATIONS_NESTED {
+        let fn_names = op.fn_list;
+        for name in fn_names {
+            let api = MathOpInfo {
+                name,
+                float_ty: op.float_ty,
+                rust_sig: op.rust_sig.clone(),
+                c_sig: op.c_sig.clone().unwrap_or_else(|| op.rust_sig.clone()),
+                public: op.public,
+            };
+            ret.push(api);
+        }
+
+        if !fn_names.is_sorted() {
+            let mut sorted = (*fn_names).to_owned();
+            sorted.sort_unstable();
+            panic!("names list is not sorted: {fn_names:?}\nExpected: {sorted:?}");
+        }
+    }
+
+    ret.sort_by_key(|item| item.name);
+    ret
+});