From 8be6ef1e0a29864131de6046dc44230b1a2e7eeb Mon Sep 17 00:00:00 2001
From: Trevor Gross <tmgross@umich.edu>
Date: Wed, 16 Oct 2024 22:47:55 -0500
Subject: [PATCH] Add numeric traits

These traits are simplified versions of what we have in
`compiler_builtins` and will be used for tests.
---
 .../libm/crates/libm-test/src/lib.rs          |   4 +
 .../libm/crates/libm-test/src/num_traits.rs   | 181 ++++++++++++++++++
 2 files changed, 185 insertions(+)
 create mode 100644 library/compiler-builtins/libm/crates/libm-test/src/num_traits.rs

diff --git a/library/compiler-builtins/libm/crates/libm-test/src/lib.rs b/library/compiler-builtins/libm/crates/libm-test/src/lib.rs
index 32c0618964fe..5444709d87cf 100644
--- a/library/compiler-builtins/libm/crates/libm-test/src/lib.rs
+++ b/library/compiler-builtins/libm/crates/libm-test/src/lib.rs
@@ -1,2 +1,6 @@
+mod num_traits;
+
+pub use num_traits::{Float, Hex, Int};
+
 // List of all files present in libm's source
 include!(concat!(env!("OUT_DIR"), "/all_files.rs"));
diff --git a/library/compiler-builtins/libm/crates/libm-test/src/num_traits.rs b/library/compiler-builtins/libm/crates/libm-test/src/num_traits.rs
new file mode 100644
index 000000000000..835d6e46d437
--- /dev/null
+++ b/library/compiler-builtins/libm/crates/libm-test/src/num_traits.rs
@@ -0,0 +1,181 @@
+use std::fmt;
+
+/// Common types and methods for floating point numbers.
+pub trait Float: Copy + fmt::Display + fmt::Debug + PartialEq<Self> {
+    type Int: Int<OtherSign = Self::SignedInt, Unsigned = Self::Int>;
+    type SignedInt: Int + Int<OtherSign = Self::Int, Unsigned = Self::Int>;
+
+    const ZERO: Self;
+    const ONE: Self;
+
+    /// The bitwidth of the float type
+    const BITS: u32;
+
+    /// The bitwidth of the significand
+    const SIGNIFICAND_BITS: u32;
+
+    /// The bitwidth of the exponent
+    const EXPONENT_BITS: u32 = Self::BITS - Self::SIGNIFICAND_BITS - 1;
+
+    fn is_nan(self) -> bool;
+    fn is_infinite(self) -> bool;
+    fn to_bits(self) -> Self::Int;
+    fn from_bits(bits: Self::Int) -> Self;
+    fn signum(self) -> Self;
+}
+
+macro_rules! impl_float {
+    ($($fty:ty, $ui:ty, $si:ty, $significand_bits:expr;)+) => {
+        $(
+            impl Float for $fty {
+                type Int = $ui;
+                type SignedInt = $si;
+
+                const ZERO: Self = 0.0;
+                const ONE: Self = 1.0;
+
+                const BITS: u32 = <$ui>::BITS;
+                const SIGNIFICAND_BITS: u32 = $significand_bits;
+
+                fn is_nan(self) -> bool {
+                    self.is_nan()
+                }
+                fn is_infinite(self) -> bool {
+                    self.is_infinite()
+                }
+                fn to_bits(self) -> Self::Int {
+                    self.to_bits()
+                }
+                fn from_bits(bits: Self::Int) -> Self {
+                    Self::from_bits(bits)
+                }
+                fn signum(self) -> Self {
+                    self.signum()
+                }
+            }
+
+            impl Hex for $fty {
+                fn hex(self) -> String {
+                    self.to_bits().hex()
+                }
+            }
+        )+
+    }
+}
+
+impl_float!(
+    f32, u32, i32, 23;
+    f64, u64, i64, 52;
+);
+
+/// Common types and methods for integers.
+pub trait Int: Copy + fmt::Display + fmt::Debug + PartialEq<Self> {
+    type OtherSign: Int;
+    type Unsigned: Int;
+    const BITS: u32;
+    const SIGNED: bool;
+
+    fn signed(self) -> <Self::Unsigned as Int>::OtherSign;
+    fn unsigned(self) -> Self::Unsigned;
+    fn checked_sub(self, other: Self) -> Option<Self>;
+    fn abs(self) -> Self;
+}
+
+macro_rules! impl_int {
+    ($($ui:ty, $si:ty ;)+) => {
+        $(
+            impl Int for $ui {
+                type OtherSign = $si;
+                type Unsigned = Self;
+                const BITS: u32 = <$ui>::BITS;
+                const SIGNED: bool = false;
+                fn signed(self) -> Self::OtherSign {
+                    self as $si
+                }
+                fn unsigned(self) -> Self {
+                    self
+                }
+                fn checked_sub(self, other: Self) -> Option<Self> {
+                    self.checked_sub(other)
+                }
+                fn abs(self) -> Self {
+                    unimplemented!()
+                }
+            }
+
+            impl Int for $si {
+                type OtherSign = $ui;
+                type Unsigned = $ui;
+                const BITS: u32 = <$ui>::BITS;
+                const SIGNED: bool = true;
+                fn signed(self) -> Self {
+                    self
+                }
+                fn unsigned(self) -> $ui {
+                    self as $ui
+                }
+                fn checked_sub(self, other: Self) -> Option<Self> {
+                    self.checked_sub(other)
+                }
+                fn abs(self) -> Self {
+                    self.abs()
+                }
+            }
+
+            impl_int!(@for_both $si);
+            impl_int!(@for_both $ui);
+
+        )+
+    };
+
+    (@for_both $ty:ty) => {
+        impl Hex for $ty {
+            fn hex(self) -> String {
+                format!("{self:#0width$x}", width = ((Self::BITS / 4) + 2) as usize)
+            }
+        }
+    }
+}
+
+impl_int!(
+    u32, i32;
+    u64, i64;
+);
+
+/// A helper trait to print something as hex with the correct number of nibbles, e.g. a `u32`
+/// will always print with `0x` followed by 8 digits.
+///
+/// This is only used for printing errors so allocating is okay.
+pub trait Hex: Copy {
+    fn hex(self) -> String;
+}
+
+impl<T1> Hex for (T1,)
+where
+    T1: Hex,
+{
+    fn hex(self) -> String {
+        format!("({},)", self.0.hex())
+    }
+}
+
+impl<T1, T2> Hex for (T1, T2)
+where
+    T1: Hex,
+    T2: Hex,
+{
+    fn hex(self) -> String {
+        format!("({}, {})", self.0.hex(), self.1.hex())
+    }
+}
+
+impl<T1, T2, T3> Hex for (T1, T2, T3)
+where
+    T1: Hex,
+    T2: Hex,
+    T3: Hex,
+{
+    fn hex(self) -> String {
+        format!("({}, {}, {})", self.0.hex(), self.1.hex(), self.2.hex())
+    }
+}