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use crate::{arena::Handle, FastHashMap, FastHashSet};
use std::borrow::Cow;
use std::hash::{Hash, Hasher};
pub type EntryPointIndex = u16;
const SEPARATOR: char = '_';
#[derive(Debug, Eq, Hash, PartialEq)]
pub enum NameKey {
Constant(Handle<crate::Constant>),
GlobalVariable(Handle<crate::GlobalVariable>),
Type(Handle<crate::Type>),
StructMember(Handle<crate::Type>, u32),
Function(Handle<crate::Function>),
FunctionArgument(Handle<crate::Function>, u32),
FunctionLocal(Handle<crate::Function>, Handle<crate::LocalVariable>),
EntryPoint(EntryPointIndex),
EntryPointLocal(EntryPointIndex, Handle<crate::LocalVariable>),
EntryPointArgument(EntryPointIndex, u32),
}
/// This processor assigns names to all the things in a module
/// that may need identifiers in a textual backend.
#[derive(Default)]
pub struct Namer {
/// The last numeric suffix used for each base name. Zero means "no suffix".
unique: FastHashMap<String, u32>,
keywords: FastHashSet<&'static str>,
keywords_case_insensitive: FastHashSet<AsciiUniCase<&'static str>>,
reserved_prefixes: Vec<&'static str>,
}
impl Namer {
/// Return a form of `string` suitable for use as the base of an identifier.
///
/// - Drop leading digits.
/// - Retain only alphanumeric and `_` characters.
/// - Avoid prefixes in [`Namer::reserved_prefixes`].
/// - Replace consecutive `_` characters with a single `_` character.
///
/// The return value is a valid identifier prefix in all of Naga's output languages,
/// and it never ends with a `SEPARATOR` character.
/// It is used as a key into the unique table.
fn sanitize<'s>(&self, string: &'s str) -> Cow<'s, str> {
let string = string
.trim_start_matches(|c: char| c.is_numeric())
.trim_end_matches(SEPARATOR);
let base = if !string.is_empty()
&& !string.contains("__")
&& string
.chars()
.all(|c: char| c.is_ascii_alphanumeric() || c == '_')
{
Cow::Borrowed(string)
} else {
let mut filtered = string
.chars()
.filter(|&c| c.is_ascii_alphanumeric() || c == '_')
.fold(String::new(), |mut s, c| {
if s.ends_with('_') && c == '_' {
return s;
}
s.push(c);
s
});
let stripped_len = filtered.trim_end_matches(SEPARATOR).len();
filtered.truncate(stripped_len);
if filtered.is_empty() {
filtered.push_str("unnamed");
}
Cow::Owned(filtered)
};
for prefix in &self.reserved_prefixes {
if base.starts_with(prefix) {
return format!("gen_{base}").into();
}
}
base
}
/// Return a new identifier based on `label_raw`.
///
/// The result:
/// - is a valid identifier even if `label_raw` is not
/// - conflicts with no keywords listed in `Namer::keywords`, and
/// - is different from any identifier previously constructed by this
/// `Namer`.
///
/// Guarantee uniqueness by applying a numeric suffix when necessary. If `label_raw`
/// itself ends with digits, separate them from the suffix with an underscore.
pub fn call(&mut self, label_raw: &str) -> String {
use std::fmt::Write as _; // for write!-ing to Strings
let base = self.sanitize(label_raw);
debug_assert!(!base.is_empty() && !base.ends_with(SEPARATOR));
// This would seem to be a natural place to use `HashMap::entry`. However, `entry`
// requires an owned key, and we'd like to avoid heap-allocating strings we're
// just going to throw away. The approach below double-hashes only when we create
// a new entry, in which case the heap allocation of the owned key was more
// expensive anyway.
match self.unique.get_mut(base.as_ref()) {
Some(count) => {
*count += 1;
// Add the suffix. This may fit in base's existing allocation.
let mut suffixed = base.into_owned();
write!(suffixed, "{}{}", SEPARATOR, *count).unwrap();
suffixed
}
None => {
let mut suffixed = base.to_string();
if base.ends_with(char::is_numeric)
|| self.keywords.contains(base.as_ref())
|| self
.keywords_case_insensitive
.contains(&AsciiUniCase(base.as_ref()))
{
suffixed.push(SEPARATOR);
}
debug_assert!(!self.keywords.contains::<str>(&suffixed));
// `self.unique` wants to own its keys. This allocates only if we haven't
// already done so earlier.
self.unique.insert(base.into_owned(), 0);
suffixed
}
}
}
pub fn call_or(&mut self, label: &Option<String>, fallback: &str) -> String {
self.call(match *label {
Some(ref name) => name,
None => fallback,
})
}
/// Enter a local namespace for things like structs.
///
/// Struct member names only need to be unique amongst themselves, not
/// globally. This function temporarily establishes a fresh, empty naming
/// context for the duration of the call to `body`.
fn namespace(&mut self, capacity: usize, body: impl FnOnce(&mut Self)) {
let fresh = FastHashMap::with_capacity_and_hasher(capacity, Default::default());
let outer = std::mem::replace(&mut self.unique, fresh);
body(self);
self.unique = outer;
}
pub fn reset(
&mut self,
module: &crate::Module,
reserved_keywords: &[&'static str],
extra_reserved_keywords: &[&'static str],
reserved_keywords_case_insensitive: &[&'static str],
reserved_prefixes: &[&'static str],
output: &mut FastHashMap<NameKey, String>,
) {
self.reserved_prefixes.clear();
self.reserved_prefixes.extend(reserved_prefixes.iter());
self.unique.clear();
self.keywords.clear();
self.keywords.extend(reserved_keywords.iter());
self.keywords.extend(extra_reserved_keywords.iter());
debug_assert!(reserved_keywords_case_insensitive
.iter()
.all(|s| s.is_ascii()));
self.keywords_case_insensitive.clear();
self.keywords_case_insensitive.extend(
reserved_keywords_case_insensitive
.iter()
.map(|string| (AsciiUniCase(*string))),
);
let mut temp = String::new();
for (ty_handle, ty) in module.types.iter() {
let ty_name = self.call_or(&ty.name, "type");
output.insert(NameKey::Type(ty_handle), ty_name);
if let crate::TypeInner::Struct { ref members, .. } = ty.inner {
// struct members have their own namespace, because access is always prefixed
self.namespace(members.len(), |namer| {
for (index, member) in members.iter().enumerate() {
let name = namer.call_or(&member.name, "member");
output.insert(NameKey::StructMember(ty_handle, index as u32), name);
}
})
}
}
for (ep_index, ep) in module.entry_points.iter().enumerate() {
let ep_name = self.call(&ep.name);
output.insert(NameKey::EntryPoint(ep_index as _), ep_name);
for (index, arg) in ep.function.arguments.iter().enumerate() {
let name = self.call_or(&arg.name, "param");
output.insert(
NameKey::EntryPointArgument(ep_index as _, index as u32),
name,
);
}
for (handle, var) in ep.function.local_variables.iter() {
let name = self.call_or(&var.name, "local");
output.insert(NameKey::EntryPointLocal(ep_index as _, handle), name);
}
}
for (fun_handle, fun) in module.functions.iter() {
let fun_name = self.call_or(&fun.name, "function");
output.insert(NameKey::Function(fun_handle), fun_name);
for (index, arg) in fun.arguments.iter().enumerate() {
let name = self.call_or(&arg.name, "param");
output.insert(NameKey::FunctionArgument(fun_handle, index as u32), name);
}
for (handle, var) in fun.local_variables.iter() {
let name = self.call_or(&var.name, "local");
output.insert(NameKey::FunctionLocal(fun_handle, handle), name);
}
}
for (handle, var) in module.global_variables.iter() {
let name = self.call_or(&var.name, "global");
output.insert(NameKey::GlobalVariable(handle), name);
}
for (handle, constant) in module.constants.iter() {
let label = match constant.name {
Some(ref name) => name,
None => {
use std::fmt::Write;
// Try to be more descriptive about the constant values
temp.clear();
write!(temp, "const_{}", output[&NameKey::Type(constant.ty)]).unwrap();
&temp
}
};
let name = self.call(label);
output.insert(NameKey::Constant(handle), name);
}
}
}
/// A string wrapper type with an ascii case insensitive Eq and Hash impl
struct AsciiUniCase<S: AsRef<str> + ?Sized>(S);
impl<S: AsRef<str>> PartialEq<Self> for AsciiUniCase<S> {
#[inline]
fn eq(&self, other: &Self) -> bool {
self.0.as_ref().eq_ignore_ascii_case(other.0.as_ref())
}
}
impl<S: AsRef<str>> Eq for AsciiUniCase<S> {}
impl<S: AsRef<str>> Hash for AsciiUniCase<S> {
#[inline]
fn hash<H: Hasher>(&self, hasher: &mut H) {
for byte in self
.0
.as_ref()
.as_bytes()
.iter()
.map(|b| b.to_ascii_lowercase())
{
hasher.write_u8(byte);
}
}
}
#[test]
fn test() {
let mut namer = Namer::default();
assert_eq!(namer.call("x"), "x");
assert_eq!(namer.call("x"), "x_1");
assert_eq!(namer.call("x1"), "x1_");
assert_eq!(namer.call("__x"), "_x");
assert_eq!(namer.call("1___x"), "_x_1");
}