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use std::fmt;
/// Many LLVM objects have a `Name`, which is either a string name, or just a
/// sequential numbering (e.g. `%3`).
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Debug, Hash)]
pub enum Name {
/// has a string name
// with `Box`, the enum `Name` has size 16 bytes, vs with a `String`
// directly, the enum `Name` has size 32 bytes. This has implications also
// for the size of other important structures, such as `Operand`.
// `Name::Name` should be the less common case, so the `Box` shouldn't hurt
// much, and we'll have much better memory consumption and maybe better
// cache performance.
Name(Box<String>),
/// doesn't have a string name and was given this sequential number
Number(usize),
}
impl Name {
pub(crate) fn name_or_num(s: String, ctr: &mut usize) -> Self {
if s.is_empty() {
let rval = Name::Number(*ctr);
*ctr += 1;
rval
} else {
Name::Name(Box::new(s))
}
}
}
impl From<String> for Name {
fn from(s: String) -> Self {
Name::Name(Box::new(s))
}
}
impl From<&str> for Name {
fn from(s: &str) -> Self {
Name::Name(Box::new(s.into()))
}
}
impl From<usize> for Name {
fn from(u: usize) -> Self {
Name::Number(u)
}
}
impl fmt::Display for Name {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
Name::Name(s) => write!(f, "%{}", s),
Name::Number(n) => write!(f, "%{}", n),
}
}
}