rust/crates/hir_def/src/body.rs
2021-01-27 12:16:24 +03:00

400 lines
13 KiB
Rust

//! Defines `Body`: a lowered representation of bodies of functions, statics and
//! consts.
mod lower;
mod diagnostics;
#[cfg(test)]
mod tests;
pub mod scope;
use std::{mem, ops::Index, sync::Arc};
use base_db::CrateId;
use cfg::CfgOptions;
use drop_bomb::DropBomb;
use either::Either;
use hir_expand::{
ast_id_map::AstIdMap, diagnostics::DiagnosticSink, hygiene::Hygiene, AstId, ExpandResult,
HirFileId, InFile, MacroDefId,
};
use la_arena::{Arena, ArenaMap};
use profile::Count;
use rustc_hash::FxHashMap;
use syntax::{ast, AstNode, AstPtr};
use test_utils::mark;
pub(crate) use lower::LowerCtx;
use crate::{
attr::{Attrs, RawAttrs},
db::DefDatabase,
expr::{Expr, ExprId, Label, LabelId, Pat, PatId},
item_scope::BuiltinShadowMode,
item_scope::ItemScope,
nameres::DefMap,
path::{ModPath, Path},
src::HasSource,
AsMacroCall, DefWithBodyId, HasModule, Lookup, ModuleId,
};
/// A subset of Expander that only deals with cfg attributes. We only need it to
/// avoid cyclic queries in crate def map during enum processing.
pub(crate) struct CfgExpander {
cfg_options: CfgOptions,
hygiene: Hygiene,
krate: CrateId,
}
pub(crate) struct Expander {
cfg_expander: CfgExpander,
crate_def_map: Arc<DefMap>,
current_file_id: HirFileId,
ast_id_map: Arc<AstIdMap>,
module: ModuleId,
recursion_limit: usize,
}
#[cfg(test)]
const EXPANSION_RECURSION_LIMIT: usize = 32;
#[cfg(not(test))]
const EXPANSION_RECURSION_LIMIT: usize = 128;
impl CfgExpander {
pub(crate) fn new(
db: &dyn DefDatabase,
current_file_id: HirFileId,
krate: CrateId,
) -> CfgExpander {
let hygiene = Hygiene::new(db.upcast(), current_file_id);
let cfg_options = db.crate_graph()[krate].cfg_options.clone();
CfgExpander { cfg_options, hygiene, krate }
}
pub(crate) fn parse_attrs(&self, db: &dyn DefDatabase, owner: &dyn ast::AttrsOwner) -> Attrs {
RawAttrs::new(owner, &self.hygiene).filter(db, self.krate)
}
pub(crate) fn is_cfg_enabled(&self, db: &dyn DefDatabase, owner: &dyn ast::AttrsOwner) -> bool {
let attrs = self.parse_attrs(db, owner);
attrs.is_cfg_enabled(&self.cfg_options)
}
}
impl Expander {
pub(crate) fn new(
db: &dyn DefDatabase,
current_file_id: HirFileId,
module: ModuleId,
) -> Expander {
let cfg_expander = CfgExpander::new(db, current_file_id, module.krate);
let crate_def_map = module.def_map(db);
let ast_id_map = db.ast_id_map(current_file_id);
Expander {
cfg_expander,
crate_def_map,
current_file_id,
ast_id_map,
module,
recursion_limit: 0,
}
}
pub(crate) fn enter_expand<T: ast::AstNode>(
&mut self,
db: &dyn DefDatabase,
local_scope: Option<&ItemScope>,
macro_call: ast::MacroCall,
) -> ExpandResult<Option<(Mark, T)>> {
if self.recursion_limit + 1 > EXPANSION_RECURSION_LIMIT {
mark::hit!(your_stack_belongs_to_me);
return ExpandResult::str_err("reached recursion limit during macro expansion".into());
}
let macro_call = InFile::new(self.current_file_id, &macro_call);
let resolver = |path: ModPath| -> Option<MacroDefId> {
if let Some(local_scope) = local_scope {
if let Some(def) = path.as_ident().and_then(|n| local_scope.get_legacy_macro(n)) {
return Some(def);
}
}
self.resolve_path_as_macro(db, &path)
};
let mut err = None;
let call_id =
macro_call.as_call_id_with_errors(db, self.crate_def_map.krate(), resolver, &mut |e| {
err.get_or_insert(e);
});
let call_id = match call_id {
Some(it) => it,
None => {
if err.is_none() {
eprintln!("no error despite `as_call_id_with_errors` returning `None`");
}
return ExpandResult { value: None, err };
}
};
if err.is_none() {
err = db.macro_expand_error(call_id);
}
let file_id = call_id.as_file();
let raw_node = match db.parse_or_expand(file_id) {
Some(it) => it,
None => {
// Only `None` if the macro expansion produced no usable AST.
if err.is_none() {
log::warn!("no error despite `parse_or_expand` failing");
}
return ExpandResult::only_err(err.unwrap_or_else(|| {
mbe::ExpandError::Other("failed to parse macro invocation".into())
}));
}
};
let node = match T::cast(raw_node) {
Some(it) => it,
None => {
// This can happen without being an error, so only forward previous errors.
return ExpandResult { value: None, err };
}
};
log::debug!("macro expansion {:#?}", node.syntax());
self.recursion_limit += 1;
let mark = Mark {
file_id: self.current_file_id,
ast_id_map: mem::take(&mut self.ast_id_map),
bomb: DropBomb::new("expansion mark dropped"),
};
self.cfg_expander.hygiene = Hygiene::new(db.upcast(), file_id);
self.current_file_id = file_id;
self.ast_id_map = db.ast_id_map(file_id);
ExpandResult { value: Some((mark, node)), err }
}
pub(crate) fn exit(&mut self, db: &dyn DefDatabase, mut mark: Mark) {
self.cfg_expander.hygiene = Hygiene::new(db.upcast(), mark.file_id);
self.current_file_id = mark.file_id;
self.ast_id_map = mem::take(&mut mark.ast_id_map);
self.recursion_limit -= 1;
mark.bomb.defuse();
}
pub(crate) fn to_source<T>(&self, value: T) -> InFile<T> {
InFile { file_id: self.current_file_id, value }
}
pub(crate) fn parse_attrs(&self, db: &dyn DefDatabase, owner: &dyn ast::AttrsOwner) -> Attrs {
self.cfg_expander.parse_attrs(db, owner)
}
pub(crate) fn cfg_options(&self) -> &CfgOptions {
&self.cfg_expander.cfg_options
}
fn parse_path(&mut self, path: ast::Path) -> Option<Path> {
Path::from_src(path, &self.cfg_expander.hygiene)
}
fn resolve_path_as_macro(&self, db: &dyn DefDatabase, path: &ModPath) -> Option<MacroDefId> {
self.crate_def_map
.resolve_path(db, self.module.local_id, path, BuiltinShadowMode::Other)
.0
.take_macros()
}
fn ast_id<N: AstNode>(&self, item: &N) -> AstId<N> {
let file_local_id = self.ast_id_map.ast_id(item);
AstId::new(self.current_file_id, file_local_id)
}
}
pub(crate) struct Mark {
file_id: HirFileId,
ast_id_map: Arc<AstIdMap>,
bomb: DropBomb,
}
/// The body of an item (function, const etc.).
#[derive(Debug, Eq, PartialEq)]
pub struct Body {
pub exprs: Arena<Expr>,
pub pats: Arena<Pat>,
pub labels: Arena<Label>,
/// The patterns for the function's parameters. While the parameter types are
/// part of the function signature, the patterns are not (they don't change
/// the external type of the function).
///
/// If this `Body` is for the body of a constant, this will just be
/// empty.
pub params: Vec<PatId>,
/// The `ExprId` of the actual body expression.
pub body_expr: ExprId,
pub item_scope: ItemScope,
_c: Count<Self>,
}
pub type ExprPtr = AstPtr<ast::Expr>;
pub type ExprSource = InFile<ExprPtr>;
pub type PatPtr = Either<AstPtr<ast::Pat>, AstPtr<ast::SelfParam>>;
pub type PatSource = InFile<PatPtr>;
pub type LabelPtr = AstPtr<ast::Label>;
pub type LabelSource = InFile<LabelPtr>;
/// An item body together with the mapping from syntax nodes to HIR expression
/// IDs. This is needed to go from e.g. a position in a file to the HIR
/// expression containing it; but for type inference etc., we want to operate on
/// a structure that is agnostic to the actual positions of expressions in the
/// file, so that we don't recompute types whenever some whitespace is typed.
///
/// One complication here is that, due to macro expansion, a single `Body` might
/// be spread across several files. So, for each ExprId and PatId, we record
/// both the HirFileId and the position inside the file. However, we only store
/// AST -> ExprId mapping for non-macro files, as it is not clear how to handle
/// this properly for macros.
#[derive(Default, Debug, Eq, PartialEq)]
pub struct BodySourceMap {
expr_map: FxHashMap<ExprSource, ExprId>,
expr_map_back: ArenaMap<ExprId, Result<ExprSource, SyntheticSyntax>>,
pat_map: FxHashMap<PatSource, PatId>,
pat_map_back: ArenaMap<PatId, Result<PatSource, SyntheticSyntax>>,
label_map: FxHashMap<LabelSource, LabelId>,
label_map_back: ArenaMap<LabelId, LabelSource>,
field_map: FxHashMap<(ExprId, usize), InFile<AstPtr<ast::RecordExprField>>>,
expansions: FxHashMap<InFile<AstPtr<ast::MacroCall>>, HirFileId>,
/// Diagnostics accumulated during body lowering. These contain `AstPtr`s and so are stored in
/// the source map (since they're just as volatile).
diagnostics: Vec<diagnostics::BodyDiagnostic>,
}
#[derive(Default, Debug, Eq, PartialEq, Clone, Copy)]
pub struct SyntheticSyntax;
impl Body {
pub(crate) fn body_with_source_map_query(
db: &dyn DefDatabase,
def: DefWithBodyId,
) -> (Arc<Body>, Arc<BodySourceMap>) {
let _p = profile::span("body_with_source_map_query");
let mut params = None;
let (file_id, module, body) = match def {
DefWithBodyId::FunctionId(f) => {
let f = f.lookup(db);
let src = f.source(db);
params = src.value.param_list();
(src.file_id, f.module(db), src.value.body().map(ast::Expr::from))
}
DefWithBodyId::ConstId(c) => {
let c = c.lookup(db);
let src = c.source(db);
(src.file_id, c.module(db), src.value.body())
}
DefWithBodyId::StaticId(s) => {
let s = s.lookup(db);
let src = s.source(db);
(src.file_id, s.module(db), src.value.body())
}
};
let expander = Expander::new(db, file_id, module);
let (body, source_map) = Body::new(db, def, expander, params, body);
(Arc::new(body), Arc::new(source_map))
}
pub(crate) fn body_query(db: &dyn DefDatabase, def: DefWithBodyId) -> Arc<Body> {
db.body_with_source_map(def).0
}
fn new(
db: &dyn DefDatabase,
def: DefWithBodyId,
expander: Expander,
params: Option<ast::ParamList>,
body: Option<ast::Expr>,
) -> (Body, BodySourceMap) {
lower::lower(db, def, expander, params, body)
}
}
impl Index<ExprId> for Body {
type Output = Expr;
fn index(&self, expr: ExprId) -> &Expr {
&self.exprs[expr]
}
}
impl Index<PatId> for Body {
type Output = Pat;
fn index(&self, pat: PatId) -> &Pat {
&self.pats[pat]
}
}
impl Index<LabelId> for Body {
type Output = Label;
fn index(&self, label: LabelId) -> &Label {
&self.labels[label]
}
}
impl BodySourceMap {
pub fn expr_syntax(&self, expr: ExprId) -> Result<ExprSource, SyntheticSyntax> {
self.expr_map_back[expr].clone()
}
pub fn node_expr(&self, node: InFile<&ast::Expr>) -> Option<ExprId> {
let src = node.map(|it| AstPtr::new(it));
self.expr_map.get(&src).cloned()
}
pub fn node_macro_file(&self, node: InFile<&ast::MacroCall>) -> Option<HirFileId> {
let src = node.map(|it| AstPtr::new(it));
self.expansions.get(&src).cloned()
}
pub fn pat_syntax(&self, pat: PatId) -> Result<PatSource, SyntheticSyntax> {
self.pat_map_back[pat].clone()
}
pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
let src = node.map(|it| Either::Left(AstPtr::new(it)));
self.pat_map.get(&src).cloned()
}
pub fn node_self_param(&self, node: InFile<&ast::SelfParam>) -> Option<PatId> {
let src = node.map(|it| Either::Right(AstPtr::new(it)));
self.pat_map.get(&src).cloned()
}
pub fn label_syntax(&self, label: LabelId) -> LabelSource {
self.label_map_back[label].clone()
}
pub fn node_label(&self, node: InFile<&ast::Label>) -> Option<LabelId> {
let src = node.map(|it| AstPtr::new(it));
self.label_map.get(&src).cloned()
}
pub fn field_syntax(&self, expr: ExprId, field: usize) -> InFile<AstPtr<ast::RecordExprField>> {
self.field_map[&(expr, field)].clone()
}
pub(crate) fn add_diagnostics(&self, _db: &dyn DefDatabase, sink: &mut DiagnosticSink<'_>) {
for diag in &self.diagnostics {
diag.add_to(sink);
}
}
}