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|
//! Macro expansion utilities.
use base_db::CrateId;
use cfg::CfgOptions;
use drop_bomb::DropBomb;
use hir_expand::{
attrs::RawAttrs, hygiene::Hygiene, mod_path::ModPath, ExpandError, ExpandResult, HirFileId,
InFile, MacroCallId, UnresolvedMacro,
};
use limit::Limit;
use syntax::{ast, Parse, SyntaxNode};
use crate::{
attr::Attrs, db::DefDatabase, lower::LowerCtx, macro_id_to_def_id, path::Path, AsMacroCall,
MacroId, 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.
#[derive(Debug)]
pub(crate) struct CfgExpander {
cfg_options: CfgOptions,
hygiene: Hygiene,
krate: CrateId,
}
#[derive(Debug)]
pub struct Expander {
cfg_expander: CfgExpander,
pub(crate) current_file_id: HirFileId,
pub(crate) module: ModuleId,
/// `recursion_depth == usize::MAX` indicates that the recursion limit has been reached.
recursion_depth: u32,
recursion_limit: Limit,
}
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::HasAttrs) -> Attrs {
Attrs::filter(db, self.krate, RawAttrs::new(db.upcast(), owner, &self.hygiene))
}
pub(crate) fn is_cfg_enabled(&self, db: &dyn DefDatabase, owner: &dyn ast::HasAttrs) -> bool {
let attrs = self.parse_attrs(db, owner);
attrs.is_cfg_enabled(&self.cfg_options)
}
pub(crate) fn hygiene(&self) -> &Hygiene {
&self.hygiene
}
}
impl Expander {
pub fn new(db: &dyn DefDatabase, current_file_id: HirFileId, module: ModuleId) -> Expander {
let cfg_expander = CfgExpander::new(db, current_file_id, module.krate);
let recursion_limit = db.recursion_limit(module.krate);
#[cfg(not(test))]
let recursion_limit = Limit::new(recursion_limit as usize);
// Without this, `body::tests::your_stack_belongs_to_me` stack-overflows in debug
#[cfg(test)]
let recursion_limit = Limit::new(std::cmp::min(32, recursion_limit as usize));
Expander { cfg_expander, current_file_id, module, recursion_depth: 0, recursion_limit }
}
pub fn enter_expand<T: ast::AstNode>(
&mut self,
db: &dyn DefDatabase,
macro_call: ast::MacroCall,
resolver: impl Fn(ModPath) -> Option<MacroId>,
) -> Result<ExpandResult<Option<(Mark, Parse<T>)>>, UnresolvedMacro> {
// FIXME: within_limit should support this, instead of us having to extract the error
let mut unresolved_macro_err = None;
let result = self.within_limit(db, |this| {
let macro_call = InFile::new(this.current_file_id, ¯o_call);
match macro_call.as_call_id_with_errors(db.upcast(), this.module.krate(), |path| {
resolver(path).map(|it| macro_id_to_def_id(db, it))
}) {
Ok(call_id) => call_id,
Err(resolve_err) => {
unresolved_macro_err = Some(resolve_err);
ExpandResult { value: None, err: None }
}
}
});
if let Some(err) = unresolved_macro_err {
Err(err)
} else {
Ok(result)
}
}
pub fn enter_expand_id<T: ast::AstNode>(
&mut self,
db: &dyn DefDatabase,
call_id: MacroCallId,
) -> ExpandResult<Option<(Mark, Parse<T>)>> {
self.within_limit(db, |_this| ExpandResult::ok(Some(call_id)))
}
fn enter_expand_inner(
db: &dyn DefDatabase,
call_id: MacroCallId,
error: Option<ExpandError>,
) -> ExpandResult<Option<InFile<Parse<SyntaxNode>>>> {
let macro_file = call_id.as_macro_file();
let ExpandResult { value, err } = db.parse_macro_expansion(macro_file);
ExpandResult { value: Some(InFile::new(macro_file.into(), value.0)), err: error.or(err) }
}
pub 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;
if self.recursion_depth == u32::MAX {
// Recursion limit has been reached somewhere in the macro expansion tree. Reset the
// depth only when we get out of the tree.
if !self.current_file_id.is_macro() {
self.recursion_depth = 0;
}
} else {
self.recursion_depth -= 1;
}
mark.bomb.defuse();
}
pub fn ctx<'a>(&self, db: &'a dyn DefDatabase) -> LowerCtx<'a> {
LowerCtx::new(db, &self.cfg_expander.hygiene, self.current_file_id)
}
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::HasAttrs) -> Attrs {
self.cfg_expander.parse_attrs(db, owner)
}
pub(crate) fn cfg_options(&self) -> &CfgOptions {
&self.cfg_expander.cfg_options
}
pub fn current_file_id(&self) -> HirFileId {
self.current_file_id
}
pub(crate) fn parse_path(&mut self, db: &dyn DefDatabase, path: ast::Path) -> Option<Path> {
let ctx = LowerCtx::new(db, &self.cfg_expander.hygiene, self.current_file_id);
Path::from_src(path, &ctx)
}
fn within_limit<F, T: ast::AstNode>(
&mut self,
db: &dyn DefDatabase,
op: F,
) -> ExpandResult<Option<(Mark, Parse<T>)>>
where
F: FnOnce(&mut Self) -> ExpandResult<Option<MacroCallId>>,
{
if self.recursion_depth == u32::MAX {
// Recursion limit has been reached somewhere in the macro expansion tree. We should
// stop expanding other macro calls in this tree, or else this may result in
// exponential number of macro expansions, leading to a hang.
//
// The overflow error should have been reported when it occurred (see the next branch),
// so don't return overflow error here to avoid diagnostics duplication.
cov_mark::hit!(overflow_but_not_me);
return ExpandResult::only_err(ExpandError::RecursionOverflowPoisoned);
} else if self.recursion_limit.check(self.recursion_depth as usize + 1).is_err() {
self.recursion_depth = u32::MAX;
cov_mark::hit!(your_stack_belongs_to_me);
return ExpandResult::only_err(ExpandError::other(
"reached recursion limit during macro expansion",
));
}
let ExpandResult { value, err } = op(self);
let Some(call_id) = value else {
return ExpandResult { value: None, err };
};
Self::enter_expand_inner(db, call_id, err).map(|value| {
value.and_then(|InFile { file_id, value }| {
let parse = value.cast::<T>()?;
self.recursion_depth += 1;
self.cfg_expander.hygiene = Hygiene::new(db.upcast(), file_id);
let old_file_id = std::mem::replace(&mut self.current_file_id, file_id);
let mark =
Mark { file_id: old_file_id, bomb: DropBomb::new("expansion mark dropped") };
Some((mark, parse))
})
})
}
}
#[derive(Debug)]
pub struct Mark {
file_id: HirFileId,
bomb: DropBomb,
}
|
