1 //! Defines `Body`: a lowered representation of bodies of functions, statics and
9 use std::{mem, ops::Index, sync::Arc};
13 use drop_bomb::DropBomb;
16 ast_id_map::AstIdMap, diagnostics::DiagnosticSink, hygiene::Hygiene, AstId, ExpandResult,
17 HirFileId, InFile, MacroDefId,
19 use la_arena::{Arena, ArenaMap};
21 use rustc_hash::FxHashMap;
22 use syntax::{ast, AstNode, AstPtr};
24 pub(crate) use lower::LowerCtx;
27 attr::{Attrs, RawAttrs},
29 expr::{Expr, ExprId, Label, LabelId, Pat, PatId},
30 item_scope::BuiltinShadowMode,
32 path::{ModPath, Path},
34 AsMacroCall, BlockId, DefWithBodyId, HasModule, LocalModuleId, Lookup, ModuleId,
38 /// A subset of Expander that only deals with cfg attributes. We only need it to
39 /// avoid cyclic queries in crate def map during enum processing.
40 pub(crate) struct CfgExpander {
41 cfg_options: CfgOptions,
46 pub(crate) struct Expander {
47 cfg_expander: CfgExpander,
49 current_file_id: HirFileId,
50 ast_id_map: Arc<AstIdMap>,
51 module: LocalModuleId,
52 recursion_limit: usize,
56 const EXPANSION_RECURSION_LIMIT: usize = 32;
59 const EXPANSION_RECURSION_LIMIT: usize = 128;
64 current_file_id: HirFileId,
67 let hygiene = Hygiene::new(db.upcast(), current_file_id);
68 let cfg_options = db.crate_graph()[krate].cfg_options.clone();
69 CfgExpander { cfg_options, hygiene, krate }
72 pub(crate) fn parse_attrs(&self, db: &dyn DefDatabase, owner: &dyn ast::AttrsOwner) -> Attrs {
73 RawAttrs::new(owner, &self.hygiene).filter(db, self.krate)
76 pub(crate) fn is_cfg_enabled(&self, db: &dyn DefDatabase, owner: &dyn ast::AttrsOwner) -> bool {
77 let attrs = self.parse_attrs(db, owner);
78 attrs.is_cfg_enabled(&self.cfg_options)
85 current_file_id: HirFileId,
88 let cfg_expander = CfgExpander::new(db, current_file_id, module.krate);
89 let def_map = module.def_map(db);
90 let ast_id_map = db.ast_id_map(current_file_id);
96 module: module.local_id,
101 pub(crate) fn enter_expand<T: ast::AstNode>(
103 db: &dyn DefDatabase,
104 macro_call: ast::MacroCall,
105 ) -> Result<ExpandResult<Option<(Mark, T)>>, UnresolvedMacro> {
106 if self.recursion_limit + 1 > EXPANSION_RECURSION_LIMIT {
107 cov_mark::hit!(your_stack_belongs_to_me);
108 return Ok(ExpandResult::str_err(
109 "reached recursion limit during macro expansion".into(),
113 let macro_call = InFile::new(self.current_file_id, ¯o_call);
116 |path: ModPath| -> Option<MacroDefId> { self.resolve_path_as_macro(db, &path) };
120 macro_call.as_call_id_with_errors(db, self.def_map.krate(), resolver, &mut |e| {
121 err.get_or_insert(e);
123 let call_id = match call_id {
126 return Ok(ExpandResult { value: None, err });
131 err = db.macro_expand_error(call_id);
134 let file_id = call_id.as_file();
136 let raw_node = match db.parse_or_expand(file_id) {
139 // Only `None` if the macro expansion produced no usable AST.
141 log::warn!("no error despite `parse_or_expand` failing");
144 return Ok(ExpandResult::only_err(err.unwrap_or_else(|| {
145 mbe::ExpandError::Other("failed to parse macro invocation".into())
150 let node = match T::cast(raw_node) {
153 // This can happen without being an error, so only forward previous errors.
154 return Ok(ExpandResult { value: None, err });
158 log::debug!("macro expansion {:#?}", node.syntax());
160 self.recursion_limit += 1;
162 file_id: self.current_file_id,
163 ast_id_map: mem::take(&mut self.ast_id_map),
164 bomb: DropBomb::new("expansion mark dropped"),
166 self.cfg_expander.hygiene = Hygiene::new(db.upcast(), file_id);
167 self.current_file_id = file_id;
168 self.ast_id_map = db.ast_id_map(file_id);
170 Ok(ExpandResult { value: Some((mark, node)), err })
173 pub(crate) fn exit(&mut self, db: &dyn DefDatabase, mut mark: Mark) {
174 self.cfg_expander.hygiene = Hygiene::new(db.upcast(), mark.file_id);
175 self.current_file_id = mark.file_id;
176 self.ast_id_map = mem::take(&mut mark.ast_id_map);
177 self.recursion_limit -= 1;
181 pub(crate) fn to_source<T>(&self, value: T) -> InFile<T> {
182 InFile { file_id: self.current_file_id, value }
185 pub(crate) fn parse_attrs(&self, db: &dyn DefDatabase, owner: &dyn ast::AttrsOwner) -> Attrs {
186 self.cfg_expander.parse_attrs(db, owner)
189 pub(crate) fn cfg_options(&self) -> &CfgOptions {
190 &self.cfg_expander.cfg_options
193 fn parse_path(&mut self, path: ast::Path) -> Option<Path> {
194 Path::from_src(path, &self.cfg_expander.hygiene)
197 fn resolve_path_as_macro(&self, db: &dyn DefDatabase, path: &ModPath) -> Option<MacroDefId> {
198 self.def_map.resolve_path(db, self.module, path, BuiltinShadowMode::Other).0.take_macros()
201 fn ast_id<N: AstNode>(&self, item: &N) -> AstId<N> {
202 let file_local_id = self.ast_id_map.ast_id(item);
203 AstId::new(self.current_file_id, file_local_id)
207 pub(crate) struct Mark {
209 ast_id_map: Arc<AstIdMap>,
213 /// The body of an item (function, const etc.).
214 #[derive(Debug, Eq, PartialEq)]
216 pub exprs: Arena<Expr>,
217 pub pats: Arena<Pat>,
218 pub labels: Arena<Label>,
219 /// The patterns for the function's parameters. While the parameter types are
220 /// part of the function signature, the patterns are not (they don't change
221 /// the external type of the function).
223 /// If this `Body` is for the body of a constant, this will just be
225 pub params: Vec<PatId>,
226 /// The `ExprId` of the actual body expression.
227 pub body_expr: ExprId,
228 /// Block expressions in this body that may contain inner items.
229 block_scopes: Vec<BlockId>,
233 pub type ExprPtr = AstPtr<ast::Expr>;
234 pub type ExprSource = InFile<ExprPtr>;
236 pub type PatPtr = Either<AstPtr<ast::Pat>, AstPtr<ast::SelfParam>>;
237 pub type PatSource = InFile<PatPtr>;
239 pub type LabelPtr = AstPtr<ast::Label>;
240 pub type LabelSource = InFile<LabelPtr>;
241 /// An item body together with the mapping from syntax nodes to HIR expression
242 /// IDs. This is needed to go from e.g. a position in a file to the HIR
243 /// expression containing it; but for type inference etc., we want to operate on
244 /// a structure that is agnostic to the actual positions of expressions in the
245 /// file, so that we don't recompute types whenever some whitespace is typed.
247 /// One complication here is that, due to macro expansion, a single `Body` might
248 /// be spread across several files. So, for each ExprId and PatId, we record
249 /// both the HirFileId and the position inside the file. However, we only store
250 /// AST -> ExprId mapping for non-macro files, as it is not clear how to handle
251 /// this properly for macros.
252 #[derive(Default, Debug, Eq, PartialEq)]
253 pub struct BodySourceMap {
254 expr_map: FxHashMap<ExprSource, ExprId>,
255 expr_map_back: ArenaMap<ExprId, Result<ExprSource, SyntheticSyntax>>,
257 pat_map: FxHashMap<PatSource, PatId>,
258 pat_map_back: ArenaMap<PatId, Result<PatSource, SyntheticSyntax>>,
260 label_map: FxHashMap<LabelSource, LabelId>,
261 label_map_back: ArenaMap<LabelId, LabelSource>,
263 /// We don't create explicit nodes for record fields (`S { record_field: 92 }`).
264 /// Instead, we use id of expression (`92`) to identify the field.
265 field_map: FxHashMap<InFile<AstPtr<ast::RecordExprField>>, ExprId>,
266 field_map_back: FxHashMap<ExprId, InFile<AstPtr<ast::RecordExprField>>>,
268 expansions: FxHashMap<InFile<AstPtr<ast::MacroCall>>, HirFileId>,
270 /// Diagnostics accumulated during body lowering. These contain `AstPtr`s and so are stored in
271 /// the source map (since they're just as volatile).
272 diagnostics: Vec<diagnostics::BodyDiagnostic>,
275 #[derive(Default, Debug, Eq, PartialEq, Clone, Copy)]
276 pub struct SyntheticSyntax;
279 pub(crate) fn body_with_source_map_query(
280 db: &dyn DefDatabase,
282 ) -> (Arc<Body>, Arc<BodySourceMap>) {
283 let _p = profile::span("body_with_source_map_query");
284 let mut params = None;
286 let (file_id, module, body) = match def {
287 DefWithBodyId::FunctionId(f) => {
288 let f = f.lookup(db);
289 let src = f.source(db);
290 params = src.value.param_list();
291 (src.file_id, f.module(db), src.value.body().map(ast::Expr::from))
293 DefWithBodyId::ConstId(c) => {
294 let c = c.lookup(db);
295 let src = c.source(db);
296 (src.file_id, c.module(db), src.value.body())
298 DefWithBodyId::StaticId(s) => {
299 let s = s.lookup(db);
300 let src = s.source(db);
301 (src.file_id, s.module(db), src.value.body())
304 let expander = Expander::new(db, file_id, module);
305 let (mut body, source_map) = Body::new(db, expander, params, body);
306 body.shrink_to_fit();
307 (Arc::new(body), Arc::new(source_map))
310 pub(crate) fn body_query(db: &dyn DefDatabase, def: DefWithBodyId) -> Arc<Body> {
311 db.body_with_source_map(def).0
314 /// Returns an iterator over all block expressions in this body that define inner items.
317 db: &'a dyn DefDatabase,
318 ) -> impl Iterator<Item = (BlockId, Arc<DefMap>)> + '_ {
321 .map(move |block| (*block, db.block_def_map(*block).expect("block ID without DefMap")))
325 db: &dyn DefDatabase,
327 params: Option<ast::ParamList>,
328 body: Option<ast::Expr>,
329 ) -> (Body, BodySourceMap) {
330 lower::lower(db, expander, params, body)
333 fn shrink_to_fit(&mut self) {
334 let Self { _c: _, body_expr: _, block_scopes, exprs, labels, params, pats } = self;
335 block_scopes.shrink_to_fit();
336 exprs.shrink_to_fit();
337 labels.shrink_to_fit();
338 params.shrink_to_fit();
339 pats.shrink_to_fit();
343 impl Index<ExprId> for Body {
346 fn index(&self, expr: ExprId) -> &Expr {
351 impl Index<PatId> for Body {
354 fn index(&self, pat: PatId) -> &Pat {
359 impl Index<LabelId> for Body {
362 fn index(&self, label: LabelId) -> &Label {
367 // FIXME: Change `node_` prefix to something more reasonable.
368 // Perhaps `expr_syntax` and `expr_id`?
370 pub fn expr_syntax(&self, expr: ExprId) -> Result<ExprSource, SyntheticSyntax> {
371 self.expr_map_back[expr].clone()
374 pub fn node_expr(&self, node: InFile<&ast::Expr>) -> Option<ExprId> {
375 let src = node.map(|it| AstPtr::new(it));
376 self.expr_map.get(&src).cloned()
379 pub fn node_macro_file(&self, node: InFile<&ast::MacroCall>) -> Option<HirFileId> {
380 let src = node.map(|it| AstPtr::new(it));
381 self.expansions.get(&src).cloned()
384 pub fn pat_syntax(&self, pat: PatId) -> Result<PatSource, SyntheticSyntax> {
385 self.pat_map_back[pat].clone()
388 pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
389 let src = node.map(|it| Either::Left(AstPtr::new(it)));
390 self.pat_map.get(&src).cloned()
393 pub fn node_self_param(&self, node: InFile<&ast::SelfParam>) -> Option<PatId> {
394 let src = node.map(|it| Either::Right(AstPtr::new(it)));
395 self.pat_map.get(&src).cloned()
398 pub fn label_syntax(&self, label: LabelId) -> LabelSource {
399 self.label_map_back[label].clone()
402 pub fn node_label(&self, node: InFile<&ast::Label>) -> Option<LabelId> {
403 let src = node.map(|it| AstPtr::new(it));
404 self.label_map.get(&src).cloned()
407 pub fn field_syntax(&self, expr: ExprId) -> InFile<AstPtr<ast::RecordExprField>> {
408 self.field_map_back[&expr].clone()
410 pub fn node_field(&self, node: InFile<&ast::RecordExprField>) -> Option<ExprId> {
411 let src = node.map(|it| AstPtr::new(it));
412 self.field_map.get(&src).cloned()
415 pub(crate) fn add_diagnostics(&self, _db: &dyn DefDatabase, sink: &mut DiagnosticSink<'_>) {
416 for diag in &self.diagnostics {