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, Label, LabelId, 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 pub labels: Arena<Label>,
230 /// The patterns for the function's parameters. While the parameter types are
231 /// part of the function signature, the patterns are not (they don't change
232 /// the external type of the function).
234 /// If this `Body` is for the body of a constant, this will just be
236 pub params: Vec<PatId>,
237 /// The `ExprId` of the actual body expression.
238 pub body_expr: ExprId,
239 pub item_scope: ItemScope,
242 pub type ExprPtr = AstPtr<ast::Expr>;
243 pub type ExprSource = InFile<ExprPtr>;
245 pub type PatPtr = Either<AstPtr<ast::Pat>, AstPtr<ast::SelfParam>>;
246 pub type PatSource = InFile<PatPtr>;
248 pub type LabelPtr = AstPtr<ast::Label>;
249 pub type LabelSource = InFile<LabelPtr>;
250 /// An item body together with the mapping from syntax nodes to HIR expression
251 /// IDs. This is needed to go from e.g. a position in a file to the HIR
252 /// expression containing it; but for type inference etc., we want to operate on
253 /// a structure that is agnostic to the actual positions of expressions in the
254 /// file, so that we don't recompute types whenever some whitespace is typed.
256 /// One complication here is that, due to macro expansion, a single `Body` might
257 /// be spread across several files. So, for each ExprId and PatId, we record
258 /// both the HirFileId and the position inside the file. However, we only store
259 /// AST -> ExprId mapping for non-macro files, as it is not clear how to handle
260 /// this properly for macros.
261 #[derive(Default, Debug, Eq, PartialEq)]
262 pub struct BodySourceMap {
263 expr_map: FxHashMap<ExprSource, ExprId>,
264 expr_map_back: ArenaMap<ExprId, Result<ExprSource, SyntheticSyntax>>,
265 pat_map: FxHashMap<PatSource, PatId>,
266 pat_map_back: ArenaMap<PatId, Result<PatSource, SyntheticSyntax>>,
267 label_map: FxHashMap<LabelSource, LabelId>,
268 label_map_back: ArenaMap<LabelId, LabelSource>,
269 field_map: FxHashMap<(ExprId, usize), InFile<AstPtr<ast::RecordExprField>>>,
270 expansions: FxHashMap<InFile<AstPtr<ast::MacroCall>>, HirFileId>,
272 /// Diagnostics accumulated during body lowering. These contain `AstPtr`s and so are stored in
273 /// the source map (since they're just as volatile).
274 diagnostics: Vec<diagnostics::BodyDiagnostic>,
277 #[derive(Default, Debug, Eq, PartialEq, Clone, Copy)]
278 pub struct SyntheticSyntax;
281 pub(crate) fn body_with_source_map_query(
282 db: &dyn DefDatabase,
284 ) -> (Arc<Body>, Arc<BodySourceMap>) {
285 let _p = profile::span("body_with_source_map_query");
286 let mut params = None;
288 let (file_id, module, body) = match def {
289 DefWithBodyId::FunctionId(f) => {
290 let f = f.lookup(db);
291 let src = f.source(db);
292 params = src.value.param_list();
293 (src.file_id, f.module(db), src.value.body().map(ast::Expr::from))
295 DefWithBodyId::ConstId(c) => {
296 let c = c.lookup(db);
297 let src = c.source(db);
298 (src.file_id, c.module(db), src.value.body())
300 DefWithBodyId::StaticId(s) => {
301 let s = s.lookup(db);
302 let src = s.source(db);
303 (src.file_id, s.module(db), src.value.body())
306 let expander = Expander::new(db, file_id, module);
307 let (body, source_map) = Body::new(db, def, expander, params, body);
308 (Arc::new(body), Arc::new(source_map))
311 pub(crate) fn body_query(db: &dyn DefDatabase, def: DefWithBodyId) -> Arc<Body> {
312 db.body_with_source_map(def).0
316 db: &dyn DefDatabase,
319 params: Option<ast::ParamList>,
320 body: Option<ast::Expr>,
321 ) -> (Body, BodySourceMap) {
322 lower::lower(db, def, expander, params, body)
326 impl Index<ExprId> for Body {
329 fn index(&self, expr: ExprId) -> &Expr {
334 impl Index<PatId> for Body {
337 fn index(&self, pat: PatId) -> &Pat {
342 impl Index<LabelId> for Body {
345 fn index(&self, label: LabelId) -> &Label {
351 pub fn expr_syntax(&self, expr: ExprId) -> Result<ExprSource, SyntheticSyntax> {
352 self.expr_map_back[expr].clone()
355 pub fn node_expr(&self, node: InFile<&ast::Expr>) -> Option<ExprId> {
356 let src = node.map(|it| AstPtr::new(it));
357 self.expr_map.get(&src).cloned()
360 pub fn node_macro_file(&self, node: InFile<&ast::MacroCall>) -> Option<HirFileId> {
361 let src = node.map(|it| AstPtr::new(it));
362 self.expansions.get(&src).cloned()
365 pub fn pat_syntax(&self, pat: PatId) -> Result<PatSource, SyntheticSyntax> {
366 self.pat_map_back[pat].clone()
369 pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
370 let src = node.map(|it| Either::Left(AstPtr::new(it)));
371 self.pat_map.get(&src).cloned()
374 pub fn node_self_param(&self, node: InFile<&ast::SelfParam>) -> Option<PatId> {
375 let src = node.map(|it| Either::Right(AstPtr::new(it)));
376 self.pat_map.get(&src).cloned()
379 pub fn label_syntax(&self, label: LabelId) -> LabelSource {
380 self.label_map_back[label].clone()
383 pub fn node_label(&self, node: InFile<&ast::Label>) -> Option<LabelId> {
384 let src = node.map(|it| AstPtr::new(it));
385 self.label_map.get(&src).cloned()
388 pub fn field_syntax(&self, expr: ExprId, field: usize) -> InFile<AstPtr<ast::RecordExprField>> {
389 self.field_map[&(expr, field)].clone()
392 pub(crate) fn add_diagnostics(&self, _db: &dyn DefDatabase, sink: &mut DiagnosticSink<'_>) {
393 for diag in &self.diagnostics {