1 //! Defines `Body`: a lowered representation of bodies of functions, statics and
9 use std::{mem, ops::Index, sync::Arc};
11 use arena::{map::ArenaMap, Arena};
14 use drop_bomb::DropBomb;
17 ast_id_map::AstIdMap, diagnostics::DiagnosticSink, hygiene::Hygiene, AstId, ExpandResult,
18 HirFileId, InFile, MacroDefId,
20 use rustc_hash::FxHashMap;
21 use syntax::{ast, AstNode, AstPtr};
24 pub(crate) use lower::LowerCtx;
27 attr::{Attrs, RawAttrs},
29 expr::{Expr, ExprId, Pat, PatId},
30 item_scope::BuiltinShadowMode,
31 item_scope::ItemScope,
33 path::{ModPath, Path},
35 AsMacroCall, DefWithBodyId, HasModule, 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,
48 crate_def_map: Arc<CrateDefMap>,
49 current_file_id: HirFileId,
50 ast_id_map: Arc<AstIdMap>,
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 crate_def_map = db.crate_def_map(module.krate);
90 let ast_id_map = db.ast_id_map(current_file_id);
101 pub(crate) fn enter_expand<T: ast::AstNode>(
103 db: &dyn DefDatabase,
104 local_scope: Option<&ItemScope>,
105 macro_call: ast::MacroCall,
106 ) -> ExpandResult<Option<(Mark, T)>> {
107 if self.recursion_limit + 1 > EXPANSION_RECURSION_LIMIT {
108 mark::hit!(your_stack_belongs_to_me);
109 return ExpandResult::str_err("reached recursion limit during macro expansion".into());
112 let macro_call = InFile::new(self.current_file_id, ¯o_call);
114 let resolver = |path: ModPath| -> Option<MacroDefId> {
115 if let Some(local_scope) = local_scope {
116 if let Some(def) = path.as_ident().and_then(|n| local_scope.get_legacy_macro(n)) {
120 self.resolve_path_as_macro(db, &path)
125 macro_call.as_call_id_with_errors(db, self.crate_def_map.krate, resolver, &mut |e| {
126 err.get_or_insert(e);
128 let call_id = match call_id {
132 eprintln!("no error despite `as_call_id_with_errors` returning `None`");
134 return ExpandResult { value: None, err };
139 err = db.macro_expand_error(call_id);
142 let file_id = call_id.as_file();
144 let raw_node = match db.parse_or_expand(file_id) {
147 // Only `None` if the macro expansion produced no usable AST.
149 log::warn!("no error despite `parse_or_expand` failing");
152 return ExpandResult::only_err(err.unwrap_or_else(|| {
153 mbe::ExpandError::Other("failed to parse macro invocation".into())
158 let node = match T::cast(raw_node) {
161 // This can happen without being an error, so only forward previous errors.
162 return ExpandResult { value: None, err };
166 log::debug!("macro expansion {:#?}", node.syntax());
168 self.recursion_limit += 1;
170 file_id: self.current_file_id,
171 ast_id_map: mem::take(&mut self.ast_id_map),
172 bomb: DropBomb::new("expansion mark dropped"),
174 self.cfg_expander.hygiene = Hygiene::new(db.upcast(), file_id);
175 self.current_file_id = file_id;
176 self.ast_id_map = db.ast_id_map(file_id);
178 ExpandResult { value: Some((mark, node)), err }
181 pub(crate) fn exit(&mut self, db: &dyn DefDatabase, mut mark: Mark) {
182 self.cfg_expander.hygiene = Hygiene::new(db.upcast(), mark.file_id);
183 self.current_file_id = mark.file_id;
184 self.ast_id_map = mem::take(&mut mark.ast_id_map);
185 self.recursion_limit -= 1;
189 pub(crate) fn to_source<T>(&self, value: T) -> InFile<T> {
190 InFile { file_id: self.current_file_id, value }
193 pub(crate) fn parse_attrs(&self, db: &dyn DefDatabase, owner: &dyn ast::AttrsOwner) -> Attrs {
194 self.cfg_expander.parse_attrs(db, owner)
197 pub(crate) fn cfg_options(&self) -> &CfgOptions {
198 &self.cfg_expander.cfg_options
201 fn parse_path(&mut self, path: ast::Path) -> Option<Path> {
202 Path::from_src(path, &self.cfg_expander.hygiene)
205 fn resolve_path_as_macro(&self, db: &dyn DefDatabase, path: &ModPath) -> Option<MacroDefId> {
207 .resolve_path(db, self.module.local_id, path, BuiltinShadowMode::Other)
212 fn ast_id<N: AstNode>(&self, item: &N) -> AstId<N> {
213 let file_local_id = self.ast_id_map.ast_id(item);
214 AstId::new(self.current_file_id, file_local_id)
218 pub(crate) struct Mark {
220 ast_id_map: Arc<AstIdMap>,
224 /// The body of an item (function, const etc.).
225 #[derive(Debug, Eq, PartialEq)]
227 pub exprs: Arena<Expr>,
228 pub pats: Arena<Pat>,
229 /// The patterns for the function's parameters. While the parameter types are
230 /// part of the function signature, the patterns are not (they don't change
231 /// the external type of the function).
233 /// If this `Body` is for the body of a constant, this will just be
235 pub params: Vec<PatId>,
236 /// The `ExprId` of the actual body expression.
237 pub body_expr: ExprId,
238 pub item_scope: ItemScope,
241 pub type ExprPtr = AstPtr<ast::Expr>;
242 pub type ExprSource = InFile<ExprPtr>;
244 pub type PatPtr = Either<AstPtr<ast::Pat>, AstPtr<ast::SelfParam>>;
245 pub type PatSource = InFile<PatPtr>;
247 /// An item body together with the mapping from syntax nodes to HIR expression
248 /// IDs. This is needed to go from e.g. a position in a file to the HIR
249 /// expression containing it; but for type inference etc., we want to operate on
250 /// a structure that is agnostic to the actual positions of expressions in the
251 /// file, so that we don't recompute types whenever some whitespace is typed.
253 /// One complication here is that, due to macro expansion, a single `Body` might
254 /// be spread across several files. So, for each ExprId and PatId, we record
255 /// both the HirFileId and the position inside the file. However, we only store
256 /// AST -> ExprId mapping for non-macro files, as it is not clear how to handle
257 /// this properly for macros.
258 #[derive(Default, Debug, Eq, PartialEq)]
259 pub struct BodySourceMap {
260 expr_map: FxHashMap<ExprSource, ExprId>,
261 expr_map_back: ArenaMap<ExprId, Result<ExprSource, SyntheticSyntax>>,
262 pat_map: FxHashMap<PatSource, PatId>,
263 pat_map_back: ArenaMap<PatId, Result<PatSource, SyntheticSyntax>>,
264 field_map: FxHashMap<(ExprId, usize), InFile<AstPtr<ast::RecordExprField>>>,
265 expansions: FxHashMap<InFile<AstPtr<ast::MacroCall>>, HirFileId>,
267 /// Diagnostics accumulated during body lowering. These contain `AstPtr`s and so are stored in
268 /// the source map (since they're just as volatile).
269 diagnostics: Vec<diagnostics::BodyDiagnostic>,
272 #[derive(Default, Debug, Eq, PartialEq, Clone, Copy)]
273 pub struct SyntheticSyntax;
276 pub(crate) fn body_with_source_map_query(
277 db: &dyn DefDatabase,
279 ) -> (Arc<Body>, Arc<BodySourceMap>) {
280 let _p = profile::span("body_with_source_map_query");
281 let mut params = None;
283 let (file_id, module, body) = match def {
284 DefWithBodyId::FunctionId(f) => {
285 let f = f.lookup(db);
286 let src = f.source(db);
287 params = src.value.param_list();
288 (src.file_id, f.module(db), src.value.body().map(ast::Expr::from))
290 DefWithBodyId::ConstId(c) => {
291 let c = c.lookup(db);
292 let src = c.source(db);
293 (src.file_id, c.module(db), src.value.body())
295 DefWithBodyId::StaticId(s) => {
296 let s = s.lookup(db);
297 let src = s.source(db);
298 (src.file_id, s.module(db), src.value.body())
301 let expander = Expander::new(db, file_id, module);
302 let (body, source_map) = Body::new(db, def, expander, params, body);
303 (Arc::new(body), Arc::new(source_map))
306 pub(crate) fn body_query(db: &dyn DefDatabase, def: DefWithBodyId) -> Arc<Body> {
307 db.body_with_source_map(def).0
311 db: &dyn DefDatabase,
314 params: Option<ast::ParamList>,
315 body: Option<ast::Expr>,
316 ) -> (Body, BodySourceMap) {
317 lower::lower(db, def, expander, params, body)
321 impl Index<ExprId> for Body {
324 fn index(&self, expr: ExprId) -> &Expr {
329 impl Index<PatId> for Body {
332 fn index(&self, pat: PatId) -> &Pat {
338 pub fn expr_syntax(&self, expr: ExprId) -> Result<ExprSource, SyntheticSyntax> {
339 self.expr_map_back[expr].clone()
342 pub fn node_expr(&self, node: InFile<&ast::Expr>) -> Option<ExprId> {
343 let src = node.map(|it| AstPtr::new(it));
344 self.expr_map.get(&src).cloned()
347 pub fn node_macro_file(&self, node: InFile<&ast::MacroCall>) -> Option<HirFileId> {
348 let src = node.map(|it| AstPtr::new(it));
349 self.expansions.get(&src).cloned()
352 pub fn pat_syntax(&self, pat: PatId) -> Result<PatSource, SyntheticSyntax> {
353 self.pat_map_back[pat].clone()
356 pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
357 let src = node.map(|it| Either::Left(AstPtr::new(it)));
358 self.pat_map.get(&src).cloned()
361 pub fn node_self_param(&self, node: InFile<&ast::SelfParam>) -> Option<PatId> {
362 let src = node.map(|it| Either::Right(AstPtr::new(it)));
363 self.pat_map.get(&src).cloned()
366 pub fn field_syntax(&self, expr: ExprId, field: usize) -> InFile<AstPtr<ast::RecordExprField>> {
367 self.field_map[&(expr, field)].clone()
370 pub(crate) fn add_diagnostics(&self, _db: &dyn DefDatabase, sink: &mut DiagnosticSink<'_>) {
371 for diag in &self.diagnostics {