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Delete counter from symbols proc macro in favor of hashmap as source of truth

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David Tolnay 2023-10-25 13:20:47 -07:00
parent 95742ff23c
commit 8dea49ad7b
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1 changed files with 24 additions and 18 deletions
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42
compiler/rustc_macros/src/symbols.rs
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@ -121,6 +121,11 @@ pub fn symbols(input: TokenStream) -> TokenStream {
output
}
struct Preinterned {
idx: u32,
span_of_name: Span,
}
fn symbols_with_errors(input: TokenStream) -> (TokenStream, Vec<syn::Error>) {
let mut errors = Errors::default();
@ -137,17 +142,20 @@ fn symbols_with_errors(input: TokenStream) -> (TokenStream, Vec<syn::Error>) {
let mut keyword_stream = quote! {};
let mut symbols_stream = quote! {};
let mut prefill_stream = quote! {};
let mut counter = 0u32;
let mut keys =
HashMap::<String, Span>::with_capacity(input.keywords.len() + input.symbols.len() + 10);
let mut entries = HashMap::<String, Preinterned>::with_capacity(
input.keywords.len() + input.symbols.len() + 10,
);
let mut prev_key: Option<(Span, String)> = None;
let mut check_dup = |span: Span, str: &str, errors: &mut Errors| {
if let Some(prev_span) = keys.get(str) {
let mut insert = |span: Span, str: &str, errors: &mut Errors| -> u32 {
if let Some(prev) = entries.get(str) {
errors.error(span, format!("Symbol `{str}` is duplicated"));
errors.error(*prev_span, "location of previous definition".to_string());
errors.error(prev.span_of_name, "location of previous definition".to_string());
prev.idx
} else {
keys.insert(str.to_string(), span);
let idx = u32::try_from(entries.len()).expect("way too many symbols");
entries.insert(str.to_string(), Preinterned { idx, span_of_name: span });
idx
}
};
@ -166,14 +174,13 @@ fn symbols_with_errors(input: TokenStream) -> (TokenStream, Vec<syn::Error>) {
let name = &keyword.name;
let value = &keyword.value;
let value_string = value.value();
check_dup(keyword.name.span(), &value_string, &mut errors);
let idx = insert(keyword.name.span(), &value_string, &mut errors);
prefill_stream.extend(quote! {
#value,
});
keyword_stream.extend(quote! {
pub const #name: Symbol = Symbol::new(#counter);
pub const #name: Symbol = Symbol::new(#idx);
});
counter += 1;
}
// Generate the listed symbols.
@ -183,32 +190,31 @@ fn symbols_with_errors(input: TokenStream) -> (TokenStream, Vec<syn::Error>) {
Value::SameAsName => name.to_string(),
Value::String(lit) => lit.value(),
};
check_dup(symbol.name.span(), &value, &mut errors);
let idx = insert(symbol.name.span(), &value, &mut errors);
check_order(symbol.name.span(), &name.to_string(), &mut errors);
prefill_stream.extend(quote! {
#value,
});
symbols_stream.extend(quote! {
pub const #name: Symbol = Symbol::new(#counter);
pub const #name: Symbol = Symbol::new(#idx);
});
counter += 1;
}
// Generate symbols for the strings "0", "1", ..., "9".
let digits_base = counter;
counter += 10;
for n in 0..10 {
let n = n.to_string();
check_dup(Span::call_site(), &n, &mut errors);
insert(Span::call_site(), &n, &mut errors);
prefill_stream.extend(quote! {
#n,
});
}
let symbol_digits_base = entries["0"].idx;
let preinterned_symbols_count = u32::try_from(entries.len()).expect("way too many symbols");
let output = quote! {
const SYMBOL_DIGITS_BASE: u32 = #digits_base;
const PREINTERNED_SYMBOLS_COUNT: u32 = #counter;
const SYMBOL_DIGITS_BASE: u32 = #symbol_digits_base;
const PREINTERNED_SYMBOLS_COUNT: u32 = #preinterned_symbols_count;
#[doc(hidden)]
#[allow(non_upper_case_globals)]