1 use proc_macro::TokenStream;
2 use proc_macro2::{Delimiter, TokenTree};
4 use syn::parse::{Parse, ParseStream, Result};
5 use syn::punctuated::Punctuated;
6 use syn::spanned::Spanned;
8 braced, parenthesized, parse_macro_input, parse_quote, AttrStyle, Attribute, Block, Error,
9 Expr, Ident, ReturnType, Token, Type,
13 syn::custom_keyword!(query);
16 /// Ident or a wildcard `_`.
17 struct IdentOrWild(Ident);
19 impl Parse for IdentOrWild {
20 fn parse(input: ParseStream<'_>) -> Result<Self> {
21 Ok(if input.peek(Token![_]) {
22 let underscore = input.parse::<Token![_]>()?;
23 IdentOrWild(Ident::new("_", underscore.span()))
25 IdentOrWild(input.parse()?)
30 /// A modifier for a query
32 /// The description of the query.
33 Desc(Option<Ident>, Punctuated<Expr, Token![,]>),
35 /// Use this type for the in-memory cache.
38 /// Cache the query to disk if the `Expr` returns true.
39 Cache(Option<(IdentOrWild, IdentOrWild)>, Block),
41 /// Custom code to load the query from disk.
42 LoadCached(Ident, Ident, Block),
44 /// A cycle error for this query aborting the compilation with a fatal error.
47 /// A cycle error results in a delay_bug call
50 /// Don't hash the result, instead just mark a query red if it runs
53 /// Generate a dep node based on the dependencies of the query
56 /// Always evaluate the query, ignoring its dependencies
60 impl Parse for QueryModifier {
61 fn parse(input: ParseStream<'_>) -> Result<Self> {
62 let modifier: Ident = input.parse()?;
63 if modifier == "desc" {
64 // Parse a description modifier like:
65 // `desc { |tcx| "foo {}", tcx.item_path(key) }`
67 braced!(attr_content in input);
68 let tcx = if attr_content.peek(Token![|]) {
69 attr_content.parse::<Token![|]>()?;
70 let tcx = attr_content.parse()?;
71 attr_content.parse::<Token![|]>()?;
76 let desc = attr_content.parse_terminated(Expr::parse)?;
77 Ok(QueryModifier::Desc(tcx, desc))
78 } else if modifier == "cache_on_disk_if" {
79 // Parse a cache modifier like:
80 // `cache(tcx, value) { |tcx| key.is_local() }`
81 let has_args = if let TokenTree::Group(group) = input.fork().parse()? {
82 group.delimiter() == Delimiter::Parenthesis
86 let args = if has_args {
88 parenthesized!(args in input);
89 let tcx = args.parse()?;
90 args.parse::<Token![,]>()?;
91 let value = args.parse()?;
96 let block = input.parse()?;
97 Ok(QueryModifier::Cache(args, block))
98 } else if modifier == "load_cached" {
99 // Parse a load_cached modifier like:
100 // `load_cached(tcx, id) { tcx.queries.on_disk_cache.try_load_query_result(tcx, id) }`
102 parenthesized!(args in input);
103 let tcx = args.parse()?;
104 args.parse::<Token![,]>()?;
105 let id = args.parse()?;
106 let block = input.parse()?;
107 Ok(QueryModifier::LoadCached(tcx, id, block))
108 } else if modifier == "storage" {
110 parenthesized!(args in input);
111 let ty = args.parse()?;
112 Ok(QueryModifier::Storage(ty))
113 } else if modifier == "fatal_cycle" {
114 Ok(QueryModifier::FatalCycle)
115 } else if modifier == "cycle_delay_bug" {
116 Ok(QueryModifier::CycleDelayBug)
117 } else if modifier == "no_hash" {
118 Ok(QueryModifier::NoHash)
119 } else if modifier == "anon" {
120 Ok(QueryModifier::Anon)
121 } else if modifier == "eval_always" {
122 Ok(QueryModifier::EvalAlways)
124 Err(Error::new(modifier.span(), "unknown query modifier"))
129 /// Ensures only doc comment attributes are used
130 fn check_attributes(attrs: Vec<Attribute>) -> Result<Vec<Attribute>> {
131 let inner = |attr: Attribute| {
132 if !attr.path.is_ident("doc") {
133 Err(Error::new(attr.span(), "attributes not supported on queries"))
134 } else if attr.style != AttrStyle::Outer {
137 "attributes must be outer attributes (`///`), not inner attributes",
143 attrs.into_iter().map(inner).collect()
146 /// A compiler query. `query ... { ... }`
148 doc_comments: Vec<Attribute>,
149 modifiers: List<QueryModifier>,
156 impl Parse for Query {
157 fn parse(input: ParseStream<'_>) -> Result<Self> {
158 let doc_comments = check_attributes(input.call(Attribute::parse_outer)?)?;
160 // Parse the query declaration. Like `query type_of(key: DefId) -> Ty<'tcx>`
161 input.parse::<kw::query>()?;
162 let name: Ident = input.parse()?;
164 parenthesized!(arg_content in input);
165 let key = arg_content.parse()?;
166 arg_content.parse::<Token![:]>()?;
167 let arg = arg_content.parse()?;
168 let result = input.parse()?;
170 // Parse the query modifiers
172 braced!(content in input);
173 let modifiers = content.parse()?;
175 Ok(Query { doc_comments, modifiers, name, key, arg, result })
179 /// A type used to greedily parse another type until the input is empty.
180 struct List<T>(Vec<T>);
182 impl<T: Parse> Parse for List<T> {
183 fn parse(input: ParseStream<'_>) -> Result<Self> {
184 let mut list = Vec::new();
185 while !input.is_empty() {
186 list.push(input.parse()?);
192 struct QueryModifiers {
193 /// The description of the query.
194 desc: (Option<Ident>, Punctuated<Expr, Token![,]>),
196 /// Use this type for the in-memory cache.
197 storage: Option<Type>,
199 /// Cache the query to disk if the `Block` returns true.
200 cache: Option<(Option<(IdentOrWild, IdentOrWild)>, Block)>,
202 /// Custom code to load the query from disk.
203 load_cached: Option<(Ident, Ident, Block)>,
205 /// A cycle error for this query aborting the compilation with a fatal error.
208 /// A cycle error results in a delay_bug call
209 cycle_delay_bug: bool,
211 /// Don't hash the result, instead just mark a query red if it runs
214 /// Generate a dep node based on the dependencies of the query
217 // Always evaluate the query, ignoring its dependencies
221 /// Process query modifiers into a struct, erroring on duplicates
222 fn process_modifiers(query: &mut Query) -> QueryModifiers {
223 let mut load_cached = None;
224 let mut storage = None;
225 let mut cache = None;
227 let mut fatal_cycle = false;
228 let mut cycle_delay_bug = false;
229 let mut no_hash = false;
230 let mut anon = false;
231 let mut eval_always = false;
232 for modifier in query.modifiers.0.drain(..) {
234 QueryModifier::LoadCached(tcx, id, block) => {
235 if load_cached.is_some() {
236 panic!("duplicate modifier `load_cached` for query `{}`", query.name);
238 load_cached = Some((tcx, id, block));
240 QueryModifier::Storage(ty) => {
241 if storage.is_some() {
242 panic!("duplicate modifier `storage` for query `{}`", query.name);
246 QueryModifier::Cache(args, expr) => {
248 panic!("duplicate modifier `cache` for query `{}`", query.name);
250 cache = Some((args, expr));
252 QueryModifier::Desc(tcx, list) => {
254 panic!("duplicate modifier `desc` for query `{}`", query.name);
256 // If there are no doc-comments, give at least some idea of what
257 // it does by showing the query description.
258 if query.doc_comments.is_empty() {
260 let mut list = list.iter();
261 let format_str: String = match list.next() {
262 Some(&Expr::Lit(ExprLit { lit: Lit::Str(ref lit_str), .. })) => {
263 lit_str.value().replace("`{}`", "{}") // We add them later anyways for consistency
265 _ => panic!("Expected a string literal"),
267 let mut fmt_fragments = format_str.split("{}");
268 let mut doc_string = fmt_fragments.next().unwrap().to_string();
269 list.map(::quote::ToTokens::to_token_stream).zip(fmt_fragments).for_each(
270 |(tts, next_fmt_fragment)| {
271 use ::core::fmt::Write;
275 tts.to_string().replace(" . ", "."),
281 let doc_string = format!(
282 "[query description - consider adding a doc-comment!] {}",
285 let comment = parse_quote! {
288 query.doc_comments.push(comment);
290 desc = Some((tcx, list));
292 QueryModifier::FatalCycle => {
294 panic!("duplicate modifier `fatal_cycle` for query `{}`", query.name);
298 QueryModifier::CycleDelayBug => {
300 panic!("duplicate modifier `cycle_delay_bug` for query `{}`", query.name);
302 cycle_delay_bug = true;
304 QueryModifier::NoHash => {
306 panic!("duplicate modifier `no_hash` for query `{}`", query.name);
310 QueryModifier::Anon => {
312 panic!("duplicate modifier `anon` for query `{}`", query.name);
316 QueryModifier::EvalAlways => {
318 panic!("duplicate modifier `eval_always` for query `{}`", query.name);
324 let desc = desc.unwrap_or_else(|| {
325 panic!("no description provided for query `{}`", query.name);
340 /// Add the impl of QueryDescription for the query to `impls` if one is requested
341 fn add_query_description_impl(
343 modifiers: QueryModifiers,
344 impls: &mut proc_macro2::TokenStream,
346 let name = &query.name;
347 let arg = &query.arg;
348 let key = &query.key.0;
350 // Find out if we should cache the query on disk
351 let cache = if let Some((args, expr)) = modifiers.cache.as_ref() {
352 let try_load_from_disk = if let Some((tcx, id, block)) = modifiers.load_cached.as_ref() {
353 // Use custom code to load the query from disk
356 fn try_load_from_disk(
358 #id: SerializedDepNodeIndex
359 ) -> Option<Self::Value> {
364 // Use the default code to load the query from disk
367 fn try_load_from_disk(
369 id: SerializedDepNodeIndex
370 ) -> Option<Self::Value> {
371 tcx.queries.on_disk_cache.as_ref().and_then(|c| c.try_load_query_result(tcx, id))
382 .unwrap_or(quote! { _ });
389 .unwrap_or(quote! { _ });
390 // expr is a `Block`, meaning that `{ #expr }` gets expanded
391 // to `{ { stmts... } }`, which triggers the `unused_braces` lint.
394 #[allow(unused_variables, unused_braces)]
398 #value: Option<&Self::Value>
406 if modifiers.load_cached.is_some() {
407 panic!("load_cached modifier on query `{}` without a cache modifier", name);
412 let (tcx, desc) = modifiers.desc;
413 let tcx = tcx.as_ref().map_or(quote! { _ }, |t| quote! { #t });
416 #[allow(unused_variables)]
420 ) -> Cow<'static, str> {
421 ::rustc_middle::ty::print::with_no_trimmed_paths(|| format!(#desc).into())
425 impls.extend(quote! {
426 impl<'tcx> QueryDescription<TyCtxt<'tcx>> for queries::#name<'tcx> {
433 pub fn rustc_queries(input: TokenStream) -> TokenStream {
434 let queries = parse_macro_input!(input as List<Query>);
436 let mut query_stream = quote! {};
437 let mut query_description_stream = quote! {};
438 let mut dep_node_def_stream = quote! {};
439 let mut cached_queries = quote! {};
441 for mut query in queries.0 {
442 let modifiers = process_modifiers(&mut query);
443 let name = &query.name;
444 let arg = &query.arg;
445 let result_full = &query.result;
446 let result = match query.result {
447 ReturnType::Default => quote! { -> () },
448 _ => quote! { #result_full },
451 if modifiers.cache.is_some() {
452 cached_queries.extend(quote! {
457 let mut attributes = Vec::new();
459 // Pass on the fatal_cycle modifier
460 if modifiers.fatal_cycle {
461 attributes.push(quote! { fatal_cycle });
463 // Pass on the storage modifier
464 if let Some(ref ty) = modifiers.storage {
465 attributes.push(quote! { storage(#ty) });
467 // Pass on the cycle_delay_bug modifier
468 if modifiers.cycle_delay_bug {
469 attributes.push(quote! { cycle_delay_bug });
471 // Pass on the no_hash modifier
472 if modifiers.no_hash {
473 attributes.push(quote! { no_hash });
475 // Pass on the anon modifier
477 attributes.push(quote! { anon });
479 // Pass on the eval_always modifier
480 if modifiers.eval_always {
481 attributes.push(quote! { eval_always });
484 let attribute_stream = quote! {#(#attributes),*};
485 let doc_comments = query.doc_comments.iter();
486 // Add the query to the group
487 query_stream.extend(quote! {
489 [#attribute_stream] fn #name(#arg) #result,
492 // Create a dep node for the query
493 dep_node_def_stream.extend(quote! {
494 [#attribute_stream] #name(#arg),
497 add_query_description_impl(&query, modifiers, &mut query_description_stream);
500 TokenStream::from(quote! {
501 macro_rules! rustc_query_append {
502 ([$($macro:tt)*][$($other:tt)*]) => {
511 macro_rules! rustc_dep_node_append {
512 ([$($macro:tt)*][$($other:tt)*]) => {
520 macro_rules! rustc_cached_queries {
522 $($macro)*(#cached_queries);
526 #query_description_stream