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Remove an allocation in find_path::find_local_import_locations

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This commit is contained in:
Lukas Wirth 2024-06-03 19:57:49 +02:00
parent 48822e0941
commit f94d34bd72
1 changed files with 17 additions and 23 deletions
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40
crates/hir-def/src/find_path.rs
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@ -155,10 +155,6 @@ fn find_path_for_module(
module_id: ModuleId, module_id: ModuleId,
max_len: usize, max_len: usize,
) -> Option<(ModPath, Stability)> { ) -> Option<(ModPath, Stability)> {
if max_len == 0 {
return None;
}
if let Some(crate_root) = module_id.as_crate_root() { if let Some(crate_root) = module_id.as_crate_root() {
if crate_root == ctx.from.derive_crate_root() { if crate_root == ctx.from.derive_crate_root() {
// - if the item is the crate root, return `crate` // - if the item is the crate root, return `crate`
@ -314,6 +310,8 @@ fn calculate_best_path(
max_len: usize, max_len: usize,
) -> Option<(ModPath, Stability)> { ) -> Option<(ModPath, Stability)> {
if max_len <= 1 { 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; 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 // Item was defined in the same crate that wants to import it. It cannot be found in any
// dependency in this case. // dependency in this case.
// FIXME: cache the `find_local_import_locations` output? // 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) { 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 // 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. // less optimal. The -1 is due to us pushing name onto it afterwards.
if let Some(path) = if let Some(path) =
find_path_for_module(ctx, visited_modules, module_id, best_path_len - 1) 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 { } else {
// Item was defined in some upstream crate. This means that it must be exported from one, // 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 // 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`. /// Finds locations in `from.krate` from which `item` can be imported by `from`.
fn find_local_import_locations( fn find_local_import_locations(
db: &dyn DefDatabase, db: &dyn DefDatabase,
item: ItemInNs, item: ItemInNs,
from: ModuleId, from: ModuleId,
def_map: &DefMap, def_map: &DefMap,
) -> Vec<(ModuleId, Name)> { mut cb: impl FnMut(&Name, ModuleId),
) {
let _p = tracing::span!(tracing::Level::INFO, "find_local_import_locations").entered(); 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 // `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 // Compute the initial worklist. We start with all direct child modules of `from` as well as all
// of its (recursive) parent modules. // of its (recursive) parent modules.
let data = &def_map[from.local_id]; let mut worklist = def_map[from.local_id]
let mut worklist = .children
data.children.values().map(|child| def_map.module_id(*child)).collect::<Vec<_>>(); .values()
// FIXME: do we need to traverse out of block expressions here? .map(|child| def_map.module_id(*child))
for ancestor in iter::successors(from.containing_module(db), |m| m.containing_module(db)) { // FIXME: do we need to traverse out of block expressions here?
worklist.push(ancestor); .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 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() { while let Some(module) = worklist.pop() {
if !seen.insert(module) { if !seen.insert(module) {
continue; // already processed this 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. // the item and we're a submodule of it, so can we.
// Also this keeps the cached data smaller. // Also this keeps the cached data smaller.
if declared || is_pub_or_explicit { 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)] #[cfg(test)]