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internal: Remove unnecessary Arc allocations in macro_expand

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This commit is contained in:
Lukas Wirth 2024-01-03 14:55:39 +01:00
parent 426d2842c1
commit 3fc043ce9b
6 changed files with 40 additions and 19 deletions
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48
crates/hir-expand/src/db.rs
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@ -390,7 +390,13 @@ fn parse_macro_expansion(
let expand_to = loc.expand_to();
let mbe::ValueResult { value: tt, err } = macro_expand(db, macro_file.macro_call_id, loc);
let (parse, rev_token_map) = token_tree_to_syntax_node(&tt, expand_to);
let (parse, rev_token_map) = token_tree_to_syntax_node(
match &tt {
CowArc::Arc(it) => it,
CowArc::Owned(it) => it,
},
expand_to,
);
ExpandResult { value: (parse, Arc::new(rev_token_map)), err }
}
@ -669,15 +675,20 @@ fn macro_expander(db: &dyn ExpandDatabase, id: MacroDefId) -> TokenExpander {
}
}
enum CowArc<T> {
Arc(Arc<T>),
Owned(T),
}
fn macro_expand(
db: &dyn ExpandDatabase,
macro_call_id: MacroCallId,
loc: MacroCallLoc,
) -> ExpandResult<Arc<tt::Subtree>> {
) -> ExpandResult<CowArc<tt::Subtree>> {
let _p = profile::span("macro_expand");
let ExpandResult { value: tt, mut err } = match loc.def.kind {
MacroDefKind::ProcMacro(..) => return db.expand_proc_macro(macro_call_id),
MacroDefKind::ProcMacro(..) => return db.expand_proc_macro(macro_call_id).map(CowArc::Arc),
MacroDefKind::BuiltInDerive(expander, ..) => {
let (root, map) = parse_with_map(db, loc.kind.file_id());
let root = root.syntax_node();
@ -692,7 +703,7 @@ fn macro_expand(
let ValueResult { value, err } = db.macro_arg(macro_call_id);
let Some((macro_arg, undo_info)) = value else {
return ExpandResult {
value: Arc::new(tt::Subtree {
value: CowArc::Owned(tt::Subtree {
delimiter: tt::Delimiter::invisible_spanned(loc.call_site),
token_trees: Vec::new(),
}),
@ -718,7 +729,7 @@ fn macro_expand(
// As such we just return the input subtree here.
MacroDefKind::BuiltInEager(..) if loc.eager.is_none() => {
return ExpandResult {
value: macro_arg.clone(),
value: CowArc::Arc(macro_arg.clone()),
err: err.map(|err| {
let mut buf = String::new();
for err in &**err {
@ -752,12 +763,17 @@ fn macro_expand(
// Skip checking token tree limit for include! macro call
if !loc.def.is_include() {
// Set a hard limit for the expanded tt
if let Err(value) = check_tt_count(&tt, loc.call_site) {
return value;
if let Err(value) = check_tt_count(&tt) {
return value.map(|()| {
CowArc::Owned(tt::Subtree {
delimiter: tt::Delimiter::invisible_spanned(loc.call_site),
token_trees: vec![],
})
});
}
}
ExpandResult { value: Arc::new(tt), err }
ExpandResult { value: CowArc::Owned(tt), err }
}
fn expand_proc_macro(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt::Subtree>> {
@ -796,8 +812,13 @@ fn expand_proc_macro(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<A
);
// Set a hard limit for the expanded tt
if let Err(value) = check_tt_count(&tt, loc.call_site) {
return value;
if let Err(value) = check_tt_count(&tt) {
return value.map(|()| {
Arc::new(tt::Subtree {
delimiter: tt::Delimiter::invisible_spanned(loc.call_site),
token_trees: vec![],
})
});
}
fixup::reverse_fixups(&mut tt, &undo_info);
@ -819,14 +840,11 @@ fn token_tree_to_syntax_node(
mbe::token_tree_to_syntax_node(tt, entry_point)
}
fn check_tt_count(tt: &tt::Subtree, call_site: Span) -> Result<(), ExpandResult<Arc<tt::Subtree>>> {
fn check_tt_count(tt: &tt::Subtree) -> Result<(), ExpandResult<()>> {
let count = tt.count();
if TOKEN_LIMIT.check(count).is_err() {
Err(ExpandResult {
value: Arc::new(tt::Subtree {
delimiter: tt::Delimiter::invisible_spanned(call_site),
token_trees: vec![],
}),
value: (),
err: Some(ExpandError::other(format!(
"macro invocation exceeds token limit: produced {} tokens, limit is {}",
count,