Remove an allocation in find_path::find_local_import_locations

This commit is contained in:
Lukas Wirth 2024-06-03 19:57:49 +02:00
parent 48822e0941
commit f94d34bd72

View file

@ -155,10 +155,6 @@ fn find_path_for_module(
module_id: ModuleId,
max_len: usize,
) -> Option<(ModPath, Stability)> {
if max_len == 0 {
return None;
}
if let Some(crate_root) = module_id.as_crate_root() {
if crate_root == ctx.from.derive_crate_root() {
// - if the item is the crate root, return `crate`
@ -314,6 +310,8 @@ fn calculate_best_path(
max_len: usize,
) -> Option<(ModPath, Stability)> {
if max_len <= 1 {
// recursive base case, we can't find a path prefix of length 0, one segment is occupied by
// the item's name itself.
return None;
}
@ -341,18 +339,18 @@ fn calculate_best_path(
// Item was defined in the same crate that wants to import it. It cannot be found in any
// dependency in this case.
// FIXME: cache the `find_local_import_locations` output?
for (module_id, name) in find_local_import_locations(db, item, ctx.from, ctx.from_def_map) {
find_local_import_locations(db, item, ctx.from, ctx.from_def_map, |name, module_id| {
if !visited_modules.insert(module_id) {
continue;
return;
}
// we are looking for paths of length up to best_path_len, any longer will make it be
// less optimal. The -1 is due to us pushing name onto it afterwards.
if let Some(path) =
find_path_for_module(ctx, visited_modules, module_id, best_path_len - 1)
{
process(path, name, &mut best_path_len);
process(path, name.clone(), &mut best_path_len);
}
}
})
} else {
// Item was defined in some upstream crate. This means that it must be exported from one,
// too (unless we can't name it at all). It could *also* be (re)exported by the same crate
@ -454,14 +452,14 @@ fn select_best_path(
}
}
// FIXME: Remove allocations
/// Finds locations in `from.krate` from which `item` can be imported by `from`.
fn find_local_import_locations(
db: &dyn DefDatabase,
item: ItemInNs,
from: ModuleId,
def_map: &DefMap,
) -> Vec<(ModuleId, Name)> {
mut cb: impl FnMut(&Name, ModuleId),
) {
let _p = tracing::span!(tracing::Level::INFO, "find_local_import_locations").entered();
// `from` can import anything below `from` with visibility of at least `from`, and anything
@ -470,19 +468,17 @@ fn find_local_import_locations(
// Compute the initial worklist. We start with all direct child modules of `from` as well as all
// of its (recursive) parent modules.
let data = &def_map[from.local_id];
let mut worklist =
data.children.values().map(|child| def_map.module_id(*child)).collect::<Vec<_>>();
// FIXME: do we need to traverse out of block expressions here?
for ancestor in iter::successors(from.containing_module(db), |m| m.containing_module(db)) {
worklist.push(ancestor);
}
let mut worklist = def_map[from.local_id]
.children
.values()
.map(|child| def_map.module_id(*child))
// FIXME: do we need to traverse out of block expressions here?
.chain(iter::successors(from.containing_module(db), |m| m.containing_module(db)))
.collect::<Vec<_>>();
let mut seen: FxHashSet<_> = FxHashSet::default();
let def_map = def_map.crate_root().def_map(db);
let mut seen: FxHashSet<_> = FxHashSet::default();
let mut locations = Vec::new();
while let Some(module) = worklist.pop() {
if !seen.insert(module) {
continue; // already processed this module
@ -523,7 +519,7 @@ fn find_local_import_locations(
// the item and we're a submodule of it, so can we.
// Also this keeps the cached data smaller.
if declared || is_pub_or_explicit {
locations.push((module, name.clone()));
cb(name, module);
}
}
}
@ -535,8 +531,6 @@ fn find_local_import_locations(
}
}
}
locations
}
#[cfg(test)]