1 //! Defines database & queries for macro expansion.
5 use base_db::{salsa, SourceDatabase};
6 use itertools::Itertools;
8 use mbe::{ExpandError, ExpandResult};
11 ast::{self, AttrsOwner, NameOwner},
12 AstNode, GreenNode, Parse, SyntaxNode, SyntaxToken, TextRange, T,
16 ast_id_map::AstIdMap, hygiene::HygieneFrame, BuiltinAttrExpander, BuiltinDeriveExpander,
17 BuiltinFnLikeExpander, ExpandTo, HirFileId, HirFileIdRepr, MacroCallId, MacroCallKind,
18 MacroCallLoc, MacroDefId, MacroDefKind, MacroFile, ProcMacroExpander,
21 /// Total limit on the number of tokens produced by any macro invocation.
23 /// If an invocation produces more tokens than this limit, it will not be stored in the database and
24 /// an error will be emitted.
26 /// Actual max for `analysis-stats .` at some point: 30672.
27 static TOKEN_LIMIT: Limit = Limit::new(524_288);
29 #[derive(Debug, Clone, Eq, PartialEq)]
30 pub enum TokenExpander {
31 /// Old-style `macro_rules`.
32 MacroRules { mac: mbe::MacroRules, def_site_token_map: mbe::TokenMap },
34 MacroDef { mac: mbe::MacroDef, def_site_token_map: mbe::TokenMap },
35 /// Stuff like `line!` and `file!`.
36 Builtin(BuiltinFnLikeExpander),
37 /// `global_allocator` and such.
38 BuiltinAttr(BuiltinAttrExpander),
39 /// `derive(Copy)` and such.
40 BuiltinDerive(BuiltinDeriveExpander),
41 /// The thing we love the most here in rust-analyzer -- procedural macros.
42 ProcMacro(ProcMacroExpander),
51 ) -> mbe::ExpandResult<tt::Subtree> {
53 TokenExpander::MacroRules { mac, .. } => mac.expand(tt),
54 TokenExpander::MacroDef { mac, .. } => mac.expand(tt),
55 TokenExpander::Builtin(it) => it.expand(db, id, tt),
56 TokenExpander::BuiltinAttr(it) => it.expand(db, id, tt),
57 TokenExpander::BuiltinDerive(it) => it.expand(db, id, tt),
58 TokenExpander::ProcMacro(_) => {
59 // We store the result in salsa db to prevent non-deterministic behavior in
60 // some proc-macro implementation
61 // See #4315 for details
62 db.expand_proc_macro(id)
67 pub(crate) fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
69 TokenExpander::MacroRules { mac, .. } => mac.map_id_down(id),
70 TokenExpander::MacroDef { mac, .. } => mac.map_id_down(id),
71 TokenExpander::Builtin(..)
72 | TokenExpander::BuiltinAttr(..)
73 | TokenExpander::BuiltinDerive(..)
74 | TokenExpander::ProcMacro(..) => id,
78 pub(crate) fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
80 TokenExpander::MacroRules { mac, .. } => mac.map_id_up(id),
81 TokenExpander::MacroDef { mac, .. } => mac.map_id_up(id),
82 TokenExpander::Builtin(..)
83 | TokenExpander::BuiltinAttr(..)
84 | TokenExpander::BuiltinDerive(..)
85 | TokenExpander::ProcMacro(..) => (id, mbe::Origin::Call),
90 // FIXME: rename to ExpandDatabase
91 #[salsa::query_group(AstDatabaseStorage)]
92 pub trait AstDatabase: SourceDatabase {
93 fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
95 /// Main public API -- parses a hir file, not caring whether it's a real
96 /// file or a macro expansion.
98 fn parse_or_expand(&self, file_id: HirFileId) -> Option<SyntaxNode>;
99 /// Implementation for the macro case.
100 fn parse_macro_expansion(
102 macro_file: MacroFile,
103 ) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>>;
105 /// Macro ids. That's probably the tricksiest bit in rust-analyzer, and the
106 /// reason why we use salsa at all.
108 /// We encode macro definitions into ids of macro calls, this what allows us
109 /// to be incremental.
111 fn intern_macro(&self, macro_call: MacroCallLoc) -> MacroCallId;
113 /// Lowers syntactic macro call to a token tree representation.
114 #[salsa::transparent]
115 fn macro_arg(&self, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>>;
116 /// Extracts syntax node, corresponding to a macro call. That's a firewall
117 /// query, only typing in the macro call itself changes the returned
119 fn macro_arg_text(&self, id: MacroCallId) -> Option<GreenNode>;
120 /// Gets the expander for this macro. This compiles declarative macros, and
121 /// just fetches procedural ones.
122 fn macro_def(&self, id: MacroDefId) -> Option<Arc<TokenExpander>>;
124 /// Expand macro call to a token tree. This query is LRUed (we keep 128 or so results in memory)
125 fn macro_expand(&self, macro_call: MacroCallId) -> ExpandResult<Option<Arc<tt::Subtree>>>;
126 /// Special case of the previous query for procedural macros. We can't LRU
127 /// proc macros, since they are not deterministic in general, and
128 /// non-determinism breaks salsa in a very, very, very bad way. @edwin0cheng
129 /// heroically debugged this once!
130 fn expand_proc_macro(&self, call: MacroCallId) -> ExpandResult<tt::Subtree>;
131 /// Firewall query that returns the error from the `macro_expand` query.
132 fn macro_expand_error(&self, macro_call: MacroCallId) -> Option<ExpandError>;
134 fn hygiene_frame(&self, file_id: HirFileId) -> Arc<HygieneFrame>;
137 /// This expands the given macro call, but with different arguments. This is
138 /// used for completion, where we want to see what 'would happen' if we insert a
139 /// token. The `token_to_map` mapped down into the expansion, with the mapped
141 pub fn expand_speculative(
142 db: &dyn AstDatabase,
143 actual_macro_call: MacroCallId,
144 speculative_args: &ast::TokenTree,
145 token_to_map: SyntaxToken,
146 ) -> Option<(SyntaxNode, SyntaxToken)> {
147 let (tt, tmap_1) = mbe::syntax_node_to_token_tree(speculative_args.syntax());
149 token_to_map.text_range().checked_sub(speculative_args.syntax().text_range().start())?;
150 let token_id = tmap_1.token_by_range(range)?;
153 let loc: MacroCallLoc = db.lookup_intern_macro(actual_macro_call);
154 db.macro_def(loc.def)?
157 let speculative_expansion = macro_def.expand(db, actual_macro_call, &tt);
159 let expand_to = macro_expand_to(db, actual_macro_call);
161 let (node, tmap_2) = token_tree_to_syntax_node(&speculative_expansion.value, expand_to).ok()?;
163 let token_id = macro_def.map_id_down(token_id);
164 let range = tmap_2.first_range_by_token(token_id, token_to_map.kind())?;
165 let token = node.syntax_node().covering_element(range).into_token()?;
166 Some((node.syntax_node(), token))
169 fn ast_id_map(db: &dyn AstDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
170 let map = db.parse_or_expand(file_id).map(|it| AstIdMap::from_source(&it)).unwrap_or_default();
174 fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Option<SyntaxNode> {
176 HirFileIdRepr::FileId(file_id) => Some(db.parse(file_id).tree().syntax().clone()),
177 HirFileIdRepr::MacroFile(macro_file) => {
178 db.parse_macro_expansion(macro_file).value.map(|(it, _)| it.syntax_node())
183 fn parse_macro_expansion(
184 db: &dyn AstDatabase,
185 macro_file: MacroFile,
186 ) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>> {
187 let _p = profile::span("parse_macro_expansion");
188 let result = db.macro_expand(macro_file.macro_call_id);
190 if let Some(err) = &result.err {
192 // The final goal we would like to make all parse_macro success,
193 // such that the following log will not call anyway.
194 let loc: MacroCallLoc = db.lookup_intern_macro(macro_file.macro_call_id);
195 let node = loc.kind.to_node(db);
197 // collect parent information for warning log
199 std::iter::successors(loc.kind.file_id().call_node(db), |it| it.file_id.call_node(db))
200 .map(|n| format!("{:#}", n.value))
205 "fail on macro_parse: (reason: {:?} macro_call: {:#}) parents: {}",
211 let tt = match result.value {
213 None => return ExpandResult { value: None, err: result.err },
216 let expand_to = macro_expand_to(db, macro_file.macro_call_id);
218 tracing::debug!("expanded = {}", tt.as_debug_string());
219 tracing::debug!("kind = {:?}", expand_to);
221 let (parse, rev_token_map) = match token_tree_to_syntax_node(&tt, expand_to) {
225 "failed to parse expansion to {:?} = {}",
229 return ExpandResult::only_err(err);
235 // Safety check for recursive identity macro.
236 let node = parse.syntax_node();
237 let file: HirFileId = macro_file.into();
238 let call_node = match file.call_node(db) {
241 return ExpandResult::only_err(err);
244 if is_self_replicating(&node, &call_node.value) {
245 ExpandResult::only_err(err)
247 ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: Some(err) }
251 tracing::debug!("parse = {:?}", parse.syntax_node().kind());
252 ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: None }
257 fn macro_arg(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>> {
258 let arg = db.macro_arg_text(id)?;
259 let loc = db.lookup_intern_macro(id);
261 let node = SyntaxNode::new_root(arg);
262 let censor = match loc.kind {
263 MacroCallKind::FnLike { .. } => None,
264 MacroCallKind::Derive { derive_attr_index, .. } => match ast::Item::cast(node.clone()) {
267 .map(|attr| attr.syntax().text_range())
268 .take(derive_attr_index as usize + 1)
269 .fold1(TextRange::cover),
272 MacroCallKind::Attr { invoc_attr_index, .. } => match ast::Item::cast(node.clone()) {
274 item.attrs().nth(invoc_attr_index as usize).map(|attr| attr.syntax().text_range())
279 let (mut tt, tmap) = mbe::syntax_node_to_token_tree_censored(&node, censor);
281 if loc.def.is_proc_macro() {
282 // proc macros expect their inputs without parentheses, MBEs expect it with them included
286 Some(Arc::new((tt, tmap)))
289 fn macro_arg_text(db: &dyn AstDatabase, id: MacroCallId) -> Option<GreenNode> {
290 let loc = db.lookup_intern_macro(id);
291 let arg = loc.kind.arg(db)?;
292 if matches!(loc.kind, MacroCallKind::FnLike { .. }) {
293 let first = arg.first_child_or_token().map_or(T![.], |it| it.kind());
294 let last = arg.last_child_or_token().map_or(T![.], |it| it.kind());
296 matches!((first, last), (T!['('], T![')']) | (T!['['], T![']']) | (T!['{'], T!['}']));
298 // Don't expand malformed (unbalanced) macro invocations. This is
299 // less than ideal, but trying to expand unbalanced macro calls
300 // sometimes produces pathological, deeply nested code which breaks
301 // all kinds of things.
303 // Some day, we'll have explicit recursion counters for all
304 // recursive things, at which point this code might be removed.
305 cov_mark::hit!(issue9358_bad_macro_stack_overflow);
309 Some(arg.green().into())
312 fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<TokenExpander>> {
314 MacroDefKind::Declarative(ast_id) => match ast_id.to_node(db) {
315 ast::Macro::MacroRules(macro_rules) => {
316 let arg = macro_rules.token_tree()?;
317 let (tt, def_site_token_map) = mbe::syntax_node_to_token_tree(arg.syntax());
318 let mac = match mbe::MacroRules::parse(&tt) {
321 let name = macro_rules.name().map(|n| n.to_string()).unwrap_or_default();
322 tracing::warn!("fail on macro_def parse ({}): {:?} {:#?}", name, err, tt);
326 Some(Arc::new(TokenExpander::MacroRules { mac, def_site_token_map }))
328 ast::Macro::MacroDef(macro_def) => {
329 let arg = macro_def.body()?;
330 let (tt, def_site_token_map) = mbe::syntax_node_to_token_tree(arg.syntax());
331 let mac = match mbe::MacroDef::parse(&tt) {
334 let name = macro_def.name().map(|n| n.to_string()).unwrap_or_default();
335 tracing::warn!("fail on macro_def parse ({}): {:?} {:#?}", name, err, tt);
339 Some(Arc::new(TokenExpander::MacroDef { mac, def_site_token_map }))
342 MacroDefKind::BuiltIn(expander, _) => Some(Arc::new(TokenExpander::Builtin(expander))),
343 MacroDefKind::BuiltInAttr(expander, _) => {
344 Some(Arc::new(TokenExpander::BuiltinAttr(expander)))
346 MacroDefKind::BuiltInDerive(expander, _) => {
347 Some(Arc::new(TokenExpander::BuiltinDerive(expander)))
349 MacroDefKind::BuiltInEager(..) => None,
350 MacroDefKind::ProcMacro(expander, ..) => Some(Arc::new(TokenExpander::ProcMacro(expander))),
354 fn macro_expand(db: &dyn AstDatabase, id: MacroCallId) -> ExpandResult<Option<Arc<tt::Subtree>>> {
355 let _p = profile::span("macro_expand");
356 let loc: MacroCallLoc = db.lookup_intern_macro(id);
357 if let Some(eager) = &loc.eager {
358 return ExpandResult {
359 value: Some(eager.arg_or_expansion.clone()),
360 // FIXME: There could be errors here!
365 let macro_arg = match db.macro_arg(id) {
367 None => return ExpandResult::str_err("Failed to lower macro args to token tree".into()),
370 let macro_rules = match db.macro_def(loc.def) {
372 None => return ExpandResult::str_err("Failed to find macro definition".into()),
374 let ExpandResult { value: tt, err } = macro_rules.expand(db, id, ¯o_arg.0);
375 // Set a hard limit for the expanded tt
376 let count = tt.count();
377 // XXX: Make ExpandResult a real error and use .map_err instead?
378 if TOKEN_LIMIT.check(count).is_err() {
379 return ExpandResult::str_err(format!(
380 "macro invocation exceeds token limit: produced {} tokens, limit is {}",
386 ExpandResult { value: Some(Arc::new(tt)), err }
389 fn macro_expand_error(db: &dyn AstDatabase, macro_call: MacroCallId) -> Option<ExpandError> {
390 db.macro_expand(macro_call).err
393 fn expand_proc_macro(db: &dyn AstDatabase, id: MacroCallId) -> ExpandResult<tt::Subtree> {
394 let loc: MacroCallLoc = db.lookup_intern_macro(id);
395 let macro_arg = match db.macro_arg(id) {
397 None => return ExpandResult::str_err("No arguments for proc-macro".to_string()),
400 let expander = match loc.def.kind {
401 MacroDefKind::ProcMacro(expander, ..) => expander,
405 let attr_arg = match &loc.kind {
406 MacroCallKind::Attr { attr_args, .. } => {
407 let mut attr_args = attr_args.0.clone();
408 mbe::Shift::new(¯o_arg.0).shift_all(&mut attr_args);
414 expander.expand(db, loc.krate, ¯o_arg.0, attr_arg.as_ref())
417 fn is_self_replicating(from: &SyntaxNode, to: &SyntaxNode) -> bool {
418 if diff(from, to).is_empty() {
421 if let Some(stmts) = ast::MacroStmts::cast(from.clone()) {
422 if stmts.statements().any(|stmt| diff(stmt.syntax(), to).is_empty()) {
425 if let Some(expr) = stmts.expr() {
426 if diff(expr.syntax(), to).is_empty() {
434 fn hygiene_frame(db: &dyn AstDatabase, file_id: HirFileId) -> Arc<HygieneFrame> {
435 Arc::new(HygieneFrame::new(db, file_id))
438 fn macro_expand_to(db: &dyn AstDatabase, id: MacroCallId) -> ExpandTo {
439 let loc: MacroCallLoc = db.lookup_intern_macro(id);
443 fn token_tree_to_syntax_node(
446 ) -> Result<(Parse<SyntaxNode>, mbe::TokenMap), ExpandError> {
447 let fragment = match expand_to {
448 ExpandTo::Statements => mbe::FragmentKind::Statements,
449 ExpandTo::Items => mbe::FragmentKind::Items,
450 ExpandTo::Pattern => mbe::FragmentKind::Pattern,
451 ExpandTo::Type => mbe::FragmentKind::Type,
452 ExpandTo::Expr => mbe::FragmentKind::Expr,
454 mbe::token_tree_to_syntax_node(tt, fragment)