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;
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,
45 pub(crate) struct Expander {
46 cfg_expander: CfgExpander,
47 crate_def_map: Arc<CrateDefMap>,
48 current_file_id: HirFileId,
49 ast_id_map: Arc<AstIdMap>,
51 recursion_limit: usize,
55 const EXPANSION_RECURSION_LIMIT: usize = 32;
58 const EXPANSION_RECURSION_LIMIT: usize = 128;
63 current_file_id: HirFileId,
66 let hygiene = Hygiene::new(db.upcast(), current_file_id);
67 let cfg_options = db.crate_graph()[krate].cfg_options.clone();
68 CfgExpander { cfg_options, hygiene }
71 pub(crate) fn parse_attrs(&self, owner: &dyn ast::AttrsOwner) -> Attrs {
72 Attrs::new(owner, &self.hygiene)
75 pub(crate) fn is_cfg_enabled(&self, owner: &dyn ast::AttrsOwner) -> bool {
76 let attrs = self.parse_attrs(owner);
77 attrs.is_cfg_enabled(&self.cfg_options)
84 current_file_id: HirFileId,
87 let cfg_expander = CfgExpander::new(db, current_file_id, module.krate);
88 let crate_def_map = db.crate_def_map(module.krate);
89 let ast_id_map = db.ast_id_map(current_file_id);
100 pub(crate) fn enter_expand<T: ast::AstNode>(
102 db: &dyn DefDatabase,
103 local_scope: Option<&ItemScope>,
104 macro_call: ast::MacroCall,
105 ) -> ExpandResult<Option<(Mark, T)>> {
106 self.recursion_limit += 1;
107 if self.recursion_limit > 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)
123 let call_id = match macro_call.as_call_id(db, self.crate_def_map.krate, resolver) {
126 // FIXME: this can mean other things too, but `as_call_id` doesn't provide enough
128 return ExpandResult::only_err(mbe::ExpandError::Other(
129 "failed to parse or resolve macro invocation".into(),
134 let err = db.macro_expand_error(call_id);
136 let file_id = call_id.as_file();
138 let raw_node = match db.parse_or_expand(file_id) {
141 // Only `None` if the macro expansion produced no usable AST.
143 log::warn!("no error despite `parse_or_expand` failing");
146 return ExpandResult::only_err(err.unwrap_or_else(|| {
147 mbe::ExpandError::Other("failed to parse macro invocation".into())
152 let node = match T::cast(raw_node) {
155 // This can happen without being an error, so only forward previous errors.
156 return ExpandResult { value: None, err };
160 log::debug!("macro expansion {:#?}", node.syntax());
163 file_id: self.current_file_id,
164 ast_id_map: mem::take(&mut self.ast_id_map),
165 bomb: DropBomb::new("expansion mark dropped"),
167 self.cfg_expander.hygiene = Hygiene::new(db.upcast(), file_id);
168 self.current_file_id = file_id;
169 self.ast_id_map = db.ast_id_map(file_id);
171 ExpandResult { value: Some((mark, node)), err }
174 pub(crate) fn exit(&mut self, db: &dyn DefDatabase, mut mark: Mark) {
175 self.cfg_expander.hygiene = Hygiene::new(db.upcast(), mark.file_id);
176 self.current_file_id = mark.file_id;
177 self.ast_id_map = mem::take(&mut mark.ast_id_map);
178 self.recursion_limit -= 1;
182 pub(crate) fn to_source<T>(&self, value: T) -> InFile<T> {
183 InFile { file_id: self.current_file_id, value }
186 pub(crate) fn parse_attrs(&self, owner: &dyn ast::AttrsOwner) -> Attrs {
187 self.cfg_expander.parse_attrs(owner)
190 pub(crate) fn cfg_options(&self) -> &CfgOptions {
191 &self.cfg_expander.cfg_options
194 fn parse_path(&mut self, path: ast::Path) -> Option<Path> {
195 Path::from_src(path, &self.cfg_expander.hygiene)
198 fn resolve_path_as_macro(&self, db: &dyn DefDatabase, path: &ModPath) -> Option<MacroDefId> {
200 .resolve_path(db, self.module.local_id, path, BuiltinShadowMode::Other)
205 fn ast_id<N: AstNode>(&self, item: &N) -> AstId<N> {
206 let file_local_id = self.ast_id_map.ast_id(item);
207 AstId::new(self.current_file_id, file_local_id)
211 pub(crate) struct Mark {
213 ast_id_map: Arc<AstIdMap>,
217 /// The body of an item (function, const etc.).
218 #[derive(Debug, Eq, PartialEq)]
220 pub exprs: Arena<Expr>,
221 pub pats: Arena<Pat>,
222 /// The patterns for the function's parameters. While the parameter types are
223 /// part of the function signature, the patterns are not (they don't change
224 /// the external type of the function).
226 /// If this `Body` is for the body of a constant, this will just be
228 pub params: Vec<PatId>,
229 /// The `ExprId` of the actual body expression.
230 pub body_expr: ExprId,
231 pub item_scope: ItemScope,
234 pub type ExprPtr = AstPtr<ast::Expr>;
235 pub type ExprSource = InFile<ExprPtr>;
237 pub type PatPtr = Either<AstPtr<ast::Pat>, AstPtr<ast::SelfParam>>;
238 pub type PatSource = InFile<PatPtr>;
240 /// An item body together with the mapping from syntax nodes to HIR expression
241 /// IDs. This is needed to go from e.g. a position in a file to the HIR
242 /// expression containing it; but for type inference etc., we want to operate on
243 /// a structure that is agnostic to the actual positions of expressions in the
244 /// file, so that we don't recompute types whenever some whitespace is typed.
246 /// One complication here is that, due to macro expansion, a single `Body` might
247 /// be spread across several files. So, for each ExprId and PatId, we record
248 /// both the HirFileId and the position inside the file. However, we only store
249 /// AST -> ExprId mapping for non-macro files, as it is not clear how to handle
250 /// this properly for macros.
251 #[derive(Default, Debug, Eq, PartialEq)]
252 pub struct BodySourceMap {
253 expr_map: FxHashMap<ExprSource, ExprId>,
254 expr_map_back: ArenaMap<ExprId, Result<ExprSource, SyntheticSyntax>>,
255 pat_map: FxHashMap<PatSource, PatId>,
256 pat_map_back: ArenaMap<PatId, Result<PatSource, SyntheticSyntax>>,
257 field_map: FxHashMap<(ExprId, usize), InFile<AstPtr<ast::RecordExprField>>>,
258 expansions: FxHashMap<InFile<AstPtr<ast::MacroCall>>, HirFileId>,
260 /// Diagnostics accumulated during body lowering. These contain `AstPtr`s and so are stored in
261 /// the source map (since they're just as volatile).
262 diagnostics: Vec<diagnostics::BodyDiagnostic>,
265 #[derive(Default, Debug, Eq, PartialEq, Clone, Copy)]
266 pub struct SyntheticSyntax;
269 pub(crate) fn body_with_source_map_query(
270 db: &dyn DefDatabase,
272 ) -> (Arc<Body>, Arc<BodySourceMap>) {
273 let _p = profile::span("body_with_source_map_query");
274 let mut params = None;
276 let (file_id, module, body) = match def {
277 DefWithBodyId::FunctionId(f) => {
278 let f = f.lookup(db);
279 let src = f.source(db);
280 params = src.value.param_list();
281 (src.file_id, f.module(db), src.value.body().map(ast::Expr::from))
283 DefWithBodyId::ConstId(c) => {
284 let c = c.lookup(db);
285 let src = c.source(db);
286 (src.file_id, c.module(db), src.value.body())
288 DefWithBodyId::StaticId(s) => {
289 let s = s.lookup(db);
290 let src = s.source(db);
291 (src.file_id, s.module(db), src.value.body())
294 let expander = Expander::new(db, file_id, module);
295 let (body, source_map) = Body::new(db, def, expander, params, body);
296 (Arc::new(body), Arc::new(source_map))
299 pub(crate) fn body_query(db: &dyn DefDatabase, def: DefWithBodyId) -> Arc<Body> {
300 db.body_with_source_map(def).0
304 db: &dyn DefDatabase,
307 params: Option<ast::ParamList>,
308 body: Option<ast::Expr>,
309 ) -> (Body, BodySourceMap) {
310 lower::lower(db, def, expander, params, body)
314 impl Index<ExprId> for Body {
317 fn index(&self, expr: ExprId) -> &Expr {
322 impl Index<PatId> for Body {
325 fn index(&self, pat: PatId) -> &Pat {
331 pub fn expr_syntax(&self, expr: ExprId) -> Result<ExprSource, SyntheticSyntax> {
332 self.expr_map_back[expr].clone()
335 pub fn node_expr(&self, node: InFile<&ast::Expr>) -> Option<ExprId> {
336 let src = node.map(|it| AstPtr::new(it));
337 self.expr_map.get(&src).cloned()
340 pub fn node_macro_file(&self, node: InFile<&ast::MacroCall>) -> Option<HirFileId> {
341 let src = node.map(|it| AstPtr::new(it));
342 self.expansions.get(&src).cloned()
345 pub fn pat_syntax(&self, pat: PatId) -> Result<PatSource, SyntheticSyntax> {
346 self.pat_map_back[pat].clone()
349 pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
350 let src = node.map(|it| Either::Left(AstPtr::new(it)));
351 self.pat_map.get(&src).cloned()
354 pub fn node_self_param(&self, node: InFile<&ast::SelfParam>) -> Option<PatId> {
355 let src = node.map(|it| Either::Right(AstPtr::new(it)));
356 self.pat_map.get(&src).cloned()
359 pub fn field_syntax(&self, expr: ExprId, field: usize) -> InFile<AstPtr<ast::RecordExprField>> {
360 self.field_map[&(expr, field)].clone()
363 pub(crate) fn add_diagnostics(&self, _db: &dyn DefDatabase, sink: &mut DiagnosticSink<'_>) {
364 for diag in &self.diagnostics {