Resolver is fast now!

Former-commit-id: 2ef6397ab9af3832fe749ce9c86c7a60a1599174

8 files changed, 755 insertions, 277 deletions

diff --git a/.vscode/launch.json b/.vscode/launch.json
index ac18a6ebb..9d5719383 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -4,7 +4,7 @@
     {
       "type": "lldb",
       "request": "launch",
-      "name": "Launch",
+      "name": "Test",
       "program": "${workspaceFolder}/zig-out/bin/test",
       "preLaunchTask": "test",
       "args": ["/usr/local/bin/zig"],
@@ -59,7 +59,7 @@
         "-o",
         "out"
       ],
-      "cwd": "${workspaceFolder}",
+      "cwd": "/Users/jarredsumner/Builds/esbuild/bench/three/src",
       "console": "internalConsole"
     }
     // {
diff --git a/src/allocators.zig b/src/allocators.zig
index b6a13ba47..ebf2186dc 100644
--- a/src/allocators.zig
+++ b/src/allocators.zig
@@ -60,20 +60,42 @@ pub fn BSSSectionAllocator(comptime size: usize) type {
     };
 }
 
+pub fn isSliceInBuffer(slice: anytype, buffer: anytype) bool {
+    return (@ptrToInt(buffer) <= @ptrToInt(slice.ptr) and (@ptrToInt(slice.ptr) + slice.len) <= (@ptrToInt(buffer) + buffer.len));
+}
+
+pub const IndexType = packed struct {
+    index: u31,
+    is_overflow: bool = false,
+};
+
 const HashKeyType = u64;
-const IndexMap = std.HashMapUnmanaged(HashKeyType, u32, hash_hashFn, hash_eqlFn, 80);
+const IndexMap = std.HashMapUnmanaged(HashKeyType, IndexType, hash_hashFn, hash_eqlFn, 80);
 pub const Result = struct {
     hash: HashKeyType,
-    index: u32,
+    index: IndexType,
     status: ItemStatus,
 
-    pub fn hasCheckedIfExists(r: *Result) bool {
-        return r.status != .unknown;
+    pub fn hasCheckedIfExists(r: *const Result) bool {
+        return r.index.index != Unassigned.index;
+    }
+
+    pub fn isOverflowing(r: *const Result, comptime count: usize) bool {
+        return r.index >= count;
+    }
+
+    pub fn realIndex(r: *const Result, comptime count: anytype) IndexType {
+        return if (r.isOverflowing(count)) @intCast(IndexType, r.index - max_index) else r.index;
     }
 };
 const Seed = 999;
-pub const NotFound = std.math.maxInt(u32);
-pub const Unassigned = NotFound - 1;
+
+pub const NotFound = IndexType{
+    .index = std.math.maxInt(u31),
+};
+pub const Unassigned = IndexType{
+    .index = std.math.maxInt(u31) - 1,
+};
 
 pub fn hash_hashFn(key: HashKeyType) HashKeyType {
     return key;
@@ -91,6 +113,245 @@ pub const ItemStatus = packed enum(u3) {
 
 const hasDeinit = std.meta.trait.hasFn("deinit")(ValueType);
 
+pub fn BSSList(comptime ValueType: type, comptime count: anytype) type {
+    const max_index = count - 1;
+    var list_type: type = undefined;
+    var list_count = count;
+    return struct {
+        pub var backing_buf: [count]ValueType = undefined;
+        pub var backing_buf_used: u16 = 0;
+        const Allocator = std.mem.Allocator;
+        const Self = @This();
+        pub const ListIndex = packed struct {
+            index: u31,
+            is_overflowing: bool = false,
+        };
+        overflow_list: std.ArrayListUnmanaged(ValueType),
+        allocator: *Allocator,
+
+        pub var instance: Self = undefined;
+
+        pub fn init(allocator: *std.mem.Allocator) *Self {
+            instance = Self{
+                .allocator = allocator,
+                .overflow_list = std.ArrayListUnmanaged(ValueType){},
+            };
+
+            return &instance;
+        }
+
+        pub fn isOverflowing() bool {
+            return backing_buf_used >= @as(u16, count);
+        }
+
+        pub fn at(self: *const Self, index: ListIndex) ?*ValueType {
+            if (index.index == NotFound.index or index.index == Unassigned.index) return null;
+
+            if (index.is_overflowing) {
+                return &self.overflow_list.items[index.index];
+            } else {
+                return &backing_buf[index.index];
+            }
+        }
+
+        pub fn exists(self: *Self, value: ValueType) bool {
+            return isSliceInBuffer(value, backing_buf);
+        }
+
+        pub fn append(self: *Self, value: ValueType) !ListIndex {
+            var result = ListIndex{ .index = std.math.maxInt(u31), .is_overflowing = backing_buf_used > max_index };
+            if (result.is_overflowing) {
+                result.index = @intCast(u31, self.overflow_list.items.len);
+                try self.overflow_list.append(self.allocator, value);
+            } else {
+                result.index = backing_buf_used;
+                backing_buf[result.index] = value;
+                backing_buf_used += 1;
+                if (backing_buf_used >= max_index) {
+                    self.overflow_list = try @TypeOf(self.overflow_list).initCapacity(self.allocator, count);
+                }
+            }
+
+            return result;
+        }
+
+        pub fn update(self: *Self, result: *ListIndex, value: ValueType) !*ValueType {
+            if (result.index.index == NotFound.index or result.index.index == Unassigned.index) {
+                result.index.is_overflowing = backing_buf_used > max_index;
+                if (result.index.is_overflowing) {
+                    result.index.index = @intCast(u31, self.overflow_list.items.len);
+                } else {
+                    result.index.index = backing_buf_used;
+                    backing_buf_used += 1;
+                    if (backing_buf_used >= max_index) {
+                        self.overflow_list = try @TypeOf(self.overflow_list).initCapacity(self.allocator, count);
+                    }
+                }
+            }
+
+            if (result.index.is_overflowing) {
+                if (self.overflow_list.items.len == result.index.index) {
+                    const real_index = self.overflow_list.items.len;
+                    try self.overflow_list.append(self.allocator, value);
+                } else {
+                    self.overflow_list.items[result.index.index] = value;
+                }
+
+                return &self.overflow_list.items[result.index.index];
+            } else {
+                backing_buf[result.index.index] = value;
+
+                return &backing_buf[result.index.index];
+            }
+        }
+
+        pub fn remove(self: *Self, index: ListIndex) void {
+            @compileError("Not implemented yet.");
+            // switch (index) {
+            //     Unassigned.index => {
+            //         self.index.remove(_key);
+            //     },
+            //     NotFound.index => {
+            //         self.index.remove(_key);
+            //     },
+            //     0...max_index => {
+            //         if (hasDeinit(ValueType)) {
+            //             backing_buf[index].deinit();
+            //         }
+            //         backing_buf[index] = undefined;
+            //     },
+            //     else => {
+            //         const i = index - count;
+            //         if (hasDeinit(ValueType)) {
+            //             self.overflow_list.items[i].deinit();
+            //         }
+            //         self.overflow_list.items[index - count] = undefined;
+            //     },
+            // }
+
+            // return index;
+        }
+    };
+}
+pub fn BSSStringList(comptime count: usize, comptime item_length: usize) type {
+    const max_index = count - 1;
+    const ValueType = []const u8;
+
+    return struct {
+        pub var slice_buf: [count][]const u8 = undefined;
+        pub var slice_buf_used: u16 = 0;
+        pub var backing_buf: [count * item_length]u8 = undefined;
+        pub var backing_buf_used: u64 = undefined;
+        const Allocator = std.mem.Allocator;
+        const Self = @This();
+        pub const ListIndex = packed struct {
+            index: u31,
+            is_overflowing: bool = false,
+        };
+        overflow_list: std.ArrayListUnmanaged(ValueType),
+        allocator: *Allocator,
+
+        pub var instance: Self = undefined;
+
+        pub fn init(allocator: *std.mem.Allocator) *Self {
+            instance = Self{
+                .allocator = allocator,
+                .overflow_list = std.ArrayListUnmanaged(ValueType){},
+            };
+
+            return &instance;
+        }
+
+        pub fn isOverflowing() bool {
+            return slice_buf_used >= @as(u16, count);
+        }
+
+        pub fn at(self: *const Self, index: IndexType) ?ValueType {
+            if (index.index == NotFound.index or index.index == Unassigned.index) return null;
+
+            if (index.is_overflowing) {
+                return &self.overflow_list.items[index.index];
+            } else {
+                return &slice_buf[index.index];
+            }
+        }
+
+        pub fn exists(self: *Self, value: ValueType) bool {
+            return isSliceInBuffer(value, slice_buf);
+        }
+
+        pub fn editableSlice(slice: []const u8) []u8 {
+            return constStrToU8(slice);
+        }
+
+        pub fn append(self: *Self, _value: anytype) ![]const u8 {
+            var value = _value;
+            if (value.len + backing_buf_used < backing_buf.len - 1) {
+                const start = backing_buf_used;
+                backing_buf_used += value.len;
+                std.mem.copy(u8, backing_buf[start..backing_buf_used], _value);
+                value = backing_buf[start..backing_buf_used];
+            } else {
+                value = try self.allocator.dupe(u8, _value);
+            }
+
+            var result = ListIndex{ .index = std.math.maxInt(u31), .is_overflowing = slice_buf_used > max_index };
+
+            if (result.is_overflowing) {
+                result.index = @intCast(u31, self.overflow_list.items.len);
+            } else {
+                result.index = slice_buf_used;
+                slice_buf_used += 1;
+                if (slice_buf_used >= max_index) {
+                    self.overflow_list = try @TypeOf(self.overflow_list).initCapacity(self.allocator, count);
+                }
+            }
+
+            if (result.is_overflowing) {
+                if (self.overflow_list.items.len == result.index) {
+                    const real_index = self.overflow_list.items.len;
+                    try self.overflow_list.append(self.allocator, value);
+                } else {
+                    self.overflow_list.items[result.index] = value;
+                }
+
+                return self.overflow_list.items[result.index];
+            } else {
+                slice_buf[result.index] = value;
+
+                return slice_buf[result.index];
+            }
+        }
+
+        pub fn remove(self: *Self, index: ListIndex) void {
+            @compileError("Not implemented yet.");
+            // switch (index) {
+            //     Unassigned.index => {
+            //         self.index.remove(_key);
+            //     },
+            //     NotFound.index => {
+            //         self.index.remove(_key);
+            //     },
+            //     0...max_index => {
+            //         if (hasDeinit(ValueType)) {
+            //             slice_buf[index].deinit();
+            //         }
+            //         slice_buf[index] = undefined;
+            //     },
+            //     else => {
+            //         const i = index - count;
+            //         if (hasDeinit(ValueType)) {
+            //             self.overflow_list.items[i].deinit();
+            //         }
+            //         self.overflow_list.items[index - count] = undefined;
+            //     },
+            // }
+
+            // return index;
+        }
+    };
+}
+
 pub fn BSSMap(comptime ValueType: type, comptime count: anytype, store_keys: bool, estimated_key_length: usize) type {
     const max_index = count - 1;
     const BSSMapType = struct {
@@ -99,8 +360,6 @@ pub fn BSSMap(comptime ValueType: type, comptime count: anytype, store_keys: boo
         const Allocator = std.mem.Allocator;
         const Self = @This();
 
-        // const HashTableAllocator = BSSSectionAllocator(@bitSizeOf(HashKeyType) * count * 2);
-
         index: IndexMap,
         overflow_list: std.ArrayListUnmanaged(ValueType),
         allocator: *Allocator,
@@ -129,9 +388,9 @@ pub fn BSSMap(comptime ValueType: type, comptime count: anytype, store_keys: boo
                 return Result{
                     .hash = _key,
                     .index = index.entry.value,
-                    .status = switch (index.entry.value) {
-                        NotFound => .not_found,
-                        Unassigned => .unknown,
+                    .status = switch (index.entry.value.index) {
+                        NotFound.index => .not_found,
+                        Unassigned.index => .unknown,
                         else => .exists,
                     },
                 };
@@ -155,43 +414,56 @@ pub fn BSSMap(comptime ValueType: type, comptime count: anytype, store_keys: boo
             self.index.put(self.allocator, result.hash, NotFound) catch unreachable;
         }
 
-        pub fn atIndex(self: *const Self, index: u32) ?*ValueType {
-            return switch (index) {
-                NotFound, Unassigned => null,
-                0...max_index => &backing_buf[index],
-                else => &self.overflow_list.items[index - count],
-            };
+        pub fn atIndex(self: *const Self, index: IndexType) ?*ValueType {
+            if (index.index == NotFound.index or index.index == Unassigned.index) return null;
+
+            if (index.is_overflow) {
+                return &self.overflow_list.items[index.index];
+            } else {
+                return &backing_buf[index.index];
+            }
         }
 
         pub fn put(self: *Self, result: *Result, value: ValueType) !*ValueType {
-            var index: u32 = @intCast(u32, backing_buf_used + 1);
-            if (index >= max_index) {
-                const real_index = self.overflow_list.items.len;
-                index += @truncate(u32, real_index);
-                try self.overflow_list.append(self.allocator, value);
-                result.index = index;
-                self.index.putAssumeCapacity(result.hash, index);
-                return &self.overflow_list.items[real_index];
-            } else {
-                backing_buf_used += 1;
-                backing_buf[index] = value;
-                result.index = index;
-                self.index.putAssumeCapacity(result.hash, index);
-                if (backing_buf_used >= max_index - 1) {
-                    self.overflow_list = try @TypeOf(self.overflow_list).initCapacity(self.allocator, count);
+            if (result.index.index == NotFound.index or result.index.index == Unassigned.index) {
+                result.index.is_overflow = backing_buf_used > max_index;
+                if (result.index.is_overflow) {
+                    result.index.index = @intCast(u31, self.overflow_list.items.len);
+                } else {
+                    result.index.index = backing_buf_used;
+                    backing_buf_used += 1;
+                    if (backing_buf_used >= max_index) {
+                        self.overflow_list = try @TypeOf(self.overflow_list).initCapacity(self.allocator, count);
+                    }
+                }
+            }
+
+            try self.index.put(self.allocator, result.hash, result.index);
+
+            if (result.index.is_overflow) {
+                if (self.overflow_list.items.len == result.index.index) {
+                    const real_index = self.overflow_list.items.len;
+                    try self.overflow_list.append(self.allocator, value);
+                } else {
+                    self.overflow_list.items[result.index.index] = value;
                 }
-                return &backing_buf[index];
+
+                return &self.overflow_list.items[result.index.index];
+            } else {
+                backing_buf[result.index.index] = value;
+
+                return &backing_buf[result.index.index];
             }
         }
 
-        pub fn remove(self: *Self, key: string) u32 {
+        pub fn remove(self: *Self, key: string) IndexType {
             const _key = Wyhash.hash(Seed, key);
             const index = self.index.get(_key) orelse return;
             switch (index) {
-                Unassigned => {
+                Unassigned.index => {
                     self.index.remove(_key);
                 },
-                NotFound => {
+                NotFound.index => {
                     self.index.remove(_key);
                 },
                 0...max_index => {
@@ -243,18 +515,19 @@ pub fn BSSMap(comptime ValueType: type, comptime count: anytype, store_keys: boo
             return @call(.{ .modifier = .always_inline }, BSSMapType.get, .{ self.map, key });
         }
 
-        pub fn atIndex(self: *Self, index: u32) ?*ValueType {
+        pub fn atIndex(self: *Self, index: IndexType) ?*ValueType {
             return @call(.{ .modifier = .always_inline }, BSSMapType.atIndex, .{ self.map, index });
         }
 
-        pub fn keyAtIndex(self: *Self, index: u32) ?[]const u8 {
-            return switch (index) {
-                Unassigned, NotFound => null,
-                0...max_index => {
-                    return key_list_slices[index];
-                },
+        pub fn keyAtIndex(self: *Self, index: IndexType) ?[]const u8 {
+            return switch (index.index) {
+                Unassigned.index, NotFound.index => null,
                 else => {
-                    return key_list_overflow.items[index - count];
+                    if (!index.is_overflow) {
+                        return key_list_slices[index.index];
+                    } else {
+                        return key_list_overflow.items[index.index];
+                    }
                 },
             };
         }
@@ -268,27 +541,40 @@ pub fn BSSMap(comptime ValueType: type, comptime count: anytype, store_keys: boo
             return ptr;
         }
 
+        pub fn isKeyStaticallyAllocated(key: anytype) bool {
+            return isSliceInBuffer(key, &key_list_buffer);
+        }
+
+        // There's two parts to this.
+        // 1. Storing the underyling string.
+        // 2. Making the key accessible at the index.
         pub fn putKey(self: *Self, key: anytype, result: *Result) !void {
-            if (key_list_buffer_used + key.len < key_list_buffer.len) {
+            var slice: []u8 = undefined;
+
+            // Is this actually a slice into the map? Don't free it.
+            if (isKeyStaticallyAllocated(key)) {
+                slice = constStrToU8(key);
+            } else if (key_list_buffer_used + key.len < key_list_buffer.len) {
                 const start = key_list_buffer_used;
                 key_list_buffer_used += key.len;
-                var slice = key_list_buffer[start..key_list_buffer_used];
+                slice = key_list_buffer[start..key_list_buffer_used];
                 std.mem.copy(u8, slice, key);
+            } else {
+                slice = try self.map.allocator.dupe(u8, key);
+            }
 
-                if (result.index < count) {
-                    key_list_slices[result.index] = slice;
+            if (!result.index.is_overflow) {
+                key_list_slices[result.index.index] = slice;
+            } else {
+                if (@intCast(u31, key_list_overflow.items.len) > result.index.index) {
+                    const existing_slice = key_list_overflow.items[result.index.index];
+                    if (!isKeyStaticallyAllocated(existing_slice)) {
+                        self.map.allocator.free(existing_slice);
+                    }
+                    key_list_overflow.items[result.index.index] = slice;
                 } else {
                     try key_list_overflow.append(self.map.allocator, slice);
                 }
-            } else if (result.index > key_list_overflow.items.len) {
-                try key_list_overflow.append(self.map.allocator, try self.map.allocator.dupe(u8, key));
-            } else {
-                const real_index = result.index - count;
-                if (key_list_overflow.items[real_index].len > 0) {
-                    self.map.allocator.free(key_list_overflow.items[real_index]);
-                }
-
-                key_list_overflow.items[real_index] = try self.map.allocator.dupe(u8, key);
             }
         }
 
@@ -297,8 +583,12 @@ pub fn BSSMap(comptime ValueType: type, comptime count: anytype, store_keys: boo
         }
 
         // For now, don't free the keys.
-        pub fn remove(self: *Self, key: string) u32 {
+        pub fn remove(self: *Self, key: string) IndexType {
             return self.map.remove(key);
         }
     };
 }
+
+fn constStrToU8(s: []const u8) []u8 {
+    return @intToPtr([*]u8, @ptrToInt(s.ptr))[0..s.len];
+}
diff --git a/src/bundler.zig b/src/bundler.zig
index a59120840..e91db985b 100644
--- a/src/bundler.zig
+++ b/src/bundler.zig
@@ -34,7 +34,7 @@ pub const Bundler = struct {
     output_files: std.ArrayList(options.OutputFile),
     resolve_results: *ResolveResults,
     resolve_queue: std.fifo.LinearFifo(Resolver.Resolver.Result, std.fifo.LinearFifoBufferType.Dynamic),
-
+    elapsed: i128 = 0,
     // to_bundle:
 
     // thread_pool: *ThreadPool,
@@ -139,8 +139,16 @@ pub const Bundler = struct {
 
         ast: js_ast.Ast,
     };
-
+    pub var tracing_start: i128 = if (enableTracing) 0 else undefined;
     pub fn parse(bundler: *Bundler, path: Fs.Path) ?ParseResult {
+        if (enableTracing) {
+            tracing_start = std.time.nanoTimestamp();
+        }
+        defer {
+            if (enableTracing) {
+                bundler.elapsed += std.time.nanoTimestamp() - tracing_start;
+            }
+        }
         var result: ParseResult = undefined;
         const loader: options.Loader = bundler.options.loaders.get(path.name.ext) orelse .file;
         const entry = bundler.resolver.caches.fs.readFile(bundler.fs, path.text) catch return null;
@@ -274,6 +282,13 @@ pub const Bundler = struct {
             else => Global.panic("Unsupported resolve mode: {s}", .{@tagName(bundler.options.resolve_mode)}),
         }
 
+        if (enableTracing) {
+            Output.print(
+                "\n---Tracing---\nResolve time:      {d}\nParsing time:      {d}\n---Tracing--\n\n",
+                .{ bundler.resolver.elapsed, bundler.elapsed },
+            );
+        }
+
         return try options.TransformResult.init(bundler.output_files.toOwnedSlice(), log, allocator);
     }
 };
diff --git a/src/fs.zig b/src/fs.zig
index 99998d446..a12c3a1f9 100644
--- a/src/fs.zig
+++ b/src/fs.zig
@@ -14,11 +14,25 @@ const allocators = @import("./allocators.zig");
 
 threadlocal var scratch_lookup_buffer: [256]u8 = undefined;
 
+pub const Preallocate = struct {
+    pub const Counts = struct {
+        pub const dir_entry: usize = 1024;
+        pub const files: usize = 2048;
+    };
+};
+
 pub const FileSystem = struct {
     allocator: *std.mem.Allocator,
     top_level_dir: string = "/",
     fs: Implementation,
 
+    dirname_store: *DirnameStore,
+    filename_store: *FilenameStore,
+    pub var instance: FileSystem = undefined;
+
+    pub const DirnameStore = allocators.BSSStringList(Preallocate.Counts.dir_entry, 256);
+    pub const FilenameStore = allocators.BSSStringList(Preallocate.Counts.files, 64);
+
     pub const Error = error{
         ENOENT,
         EACCESS,
@@ -27,22 +41,74 @@ pub const FileSystem = struct {
     };
 
     pub fn init1(allocator: *std.mem.Allocator, top_level_dir: ?string, enable_watcher: bool) !*FileSystem {
-        var files = try allocator.create(FileSystem);
-        files.* = FileSystem{
+        const _top_level_dir = top_level_dir orelse (if (isBrowser) "/project" else try std.process.getCwdAlloc(allocator));
+
+        instance = FileSystem{
             .allocator = allocator,
-            .top_level_dir = top_level_dir orelse (if (isBrowser) "/project" else try std.process.getCwdAlloc(allocator)),
-            .fs = Implementation.init(allocator, enable_watcher),
+            .top_level_dir = _top_level_dir,
+            .fs = Implementation.init(allocator, _top_level_dir, enable_watcher),
             // .stats = std.StringHashMap(Stat).init(allocator),
+            .dirname_store = DirnameStore.init(allocator),
+            .filename_store = FilenameStore.init(allocator),
         };
 
-        return files;
+        instance.fs.parent_fs = &instance;
+        _ = DirEntry.EntryStore.init(allocator);
+        return &instance;
     }
 
     pub const DirEntry = struct {
-        pub const EntryMap = std.StringArrayHashMap(*Entry);
+        pub const EntryMap = std.StringHashMap(EntryStore.ListIndex);
+        pub const EntryStore = allocators.BSSList(Entry, Preallocate.Counts.files);
         dir: string,
         data: EntryMap,
 
+        pub fn addEntry(dir: *DirEntry, entry: std.fs.Dir.Entry) !void {
+            var _kind: Entry.Kind = undefined;
+            switch (entry.kind) {
+                .Directory => {
+                    _kind = Entry.Kind.dir;
+                },
+                .SymLink => {
+                    // This might be wrong!
+                    _kind = Entry.Kind.file;
+                },
+                .File => {
+                    _kind = Entry.Kind.file;
+                },
+                else => {
+                    return;
+                },
+            }
+            // entry.name only lives for the duration of the iteration
+            var name = FileSystem.FilenameStore.editableSlice(try FileSystem.FilenameStore.instance.append(entry.name));
+
+            for (entry.name) |c, i| {
+                name[i] = std.ascii.toLower(c);
+            }
+
+            var symlink: []u8 = "";
+
+            if (entry.kind == std.fs.Dir.Entry.Kind.SymLink) {
+                symlink = name;
+            }
+            const index = try EntryStore.instance.append(Entry{
+                .base = name,
+                .dir = dir.dir,
+                .mutex = Mutex.init(),
+                // Call "stat" lazily for performance. The "@material-ui/icons" package
+                // contains a directory with over 11,000 entries in it and running "stat"
+                // for each entry was a big performance issue for that package.
+                .need_stat = entry.kind == .SymLink,
+                .cache = Entry.Cache{
+                    .symlink = symlink,
+                    .kind = _kind,
+                },
+            });
+
+            try dir.data.put(name, index);
+        }
+
         pub fn updateDir(i: *DirEntry, dir: string) void {
             var iter = i.data.iterator();
             i.dir = dir;
@@ -67,9 +133,11 @@ pub const FileSystem = struct {
         pub fn deinit(d: *DirEntry) void {
             d.data.allocator.free(d.dir);
 
-            for (d.data.items()) |item| {
-                item.value.deinit(d.data.allocator);
+            var iter = d.data.iterator();
+            while (iter.next()) |file_entry| {
+                EntryStore.instance.at(file_entry.value).?.deinit(d.data.allocator);
             }
+
             d.data.deinit();
         }
 
@@ -83,7 +151,8 @@ pub const FileSystem = struct {
                 end = i;
             }
             const query = scratch_lookup_buffer[0 .. end + 1];
-            const result = entry.data.get(query) orelse return null;
+            const result_index = entry.data.get(query) orelse return null;
+            const result = EntryStore.instance.at(result_index) orelse return null;
             if (!strings.eql(result.base, query)) {
                 return Entry.Lookup{ .entry = result, .diff_case = Entry.Lookup.DifferentCase{
                     .dir = entry.dir,
@@ -132,8 +201,8 @@ pub const FileSystem = struct {
         };
 
         pub fn kind(entry: *Entry, fs: *Implementation) Kind {
-            entry.mutex.lock();
-            defer entry.mutex.unlock();
+            // entry.mutex.lock();
+            // defer entry.mutex.unlock();
             if (entry.need_stat) {
                 entry.need_stat = false;
                 entry.cache = fs.kind(entry.dir, entry.base) catch unreachable;
@@ -142,8 +211,8 @@ pub const FileSystem = struct {
         }
 
         pub fn symlink(entry: *Entry, fs: *Implementation) string {
-            entry.mutex.lock();
-            defer entry.mutex.unlock();
+            // entry.mutex.lock();
+            // defer entry.mutex.unlock();
             if (entry.need_stat) {
                 entry.need_stat = false;
                 entry.cache = fs.kind(entry.dir, entry.base) catch unreachable;
@@ -189,11 +258,14 @@ pub const FileSystem = struct {
         limiter: Limiter,
         watcher: ?std.StringHashMap(WatchData) = null,
         watcher_mutex: Mutex = Mutex.init(),
+        cwd: string,
+        parent_fs: *FileSystem = undefined,
 
-        pub fn init(allocator: *std.mem.Allocator, enable_watcher: bool) RealFS {
+        pub fn init(allocator: *std.mem.Allocator, cwd: string, enable_watcher: bool) RealFS {
             return RealFS{
                 .entries = EntriesOption.Map.init(allocator),
                 .allocator = allocator,
+                .cwd = cwd,
                 .limiter = Limiter.init(allocator),
                 .watcher = if (enable_watcher) std.StringHashMap(WatchData).init(allocator) else null,
             };
@@ -306,7 +378,7 @@ pub const FileSystem = struct {
             // This custom map implementation:
             // - Preallocates a fixed amount of directory name space
             // - Doesn't store directory names which don't exist.
-            pub const Map = allocators.BSSMap(EntriesOption, 1024, true, 128);
+            pub const Map = allocators.BSSMap(EntriesOption, Preallocate.Counts.dir_entry, false, 128);
         };
 
         // Limit the number of files open simultaneously to avoid ulimit issues
@@ -337,7 +409,7 @@ pub const FileSystem = struct {
         };
 
         pub fn openDir(fs: *RealFS, unsafe_dir_string: string) std.fs.File.OpenError!std.fs.Dir {
-            return try std.fs.openDirAbsolute(unsafe_dir_string, std.fs.Dir.OpenDirOptions{ .iterate = true, .access_sub_paths = true });
+            return try std.fs.openDirAbsolute(unsafe_dir_string, std.fs.Dir.OpenDirOptions{ .iterate = true, .access_sub_paths = true, .no_follow = true });
         }
 
         fn readdir(
@@ -349,48 +421,10 @@ pub const FileSystem = struct {
             defer fs.limiter.after();
 
             var iter: std.fs.Dir.Iterator = handle.iterate();
-            var dir = DirEntry.init("", fs.allocator);
+            var dir = DirEntry.init(_dir, fs.allocator);
             errdefer dir.deinit();
             while (try iter.next()) |_entry| {
-                const entry: std.fs.Dir.Entry = _entry;
-                var _kind: Entry.Kind = undefined;
-                switch (entry.kind) {
-                    .Directory => {
-                        _kind = Entry.Kind.dir;
-                    },
-                    .SymLink => {
-                        // This might be wrong!
-                        _kind = Entry.Kind.file;
-                    },
-                    .File => {
-                        _kind = Entry.Kind.file;
-                    },
-                    else => {
-                        continue;
-                    },
-                }
-
-                // entry.name only lives for the duration of the iteration
-                var name = try fs.allocator.alloc(u8, entry.name.len);
-                for (entry.name) |c, i| {
-                    name[i] = std.ascii.toLower(c);
-                }
-                var entry_ptr = try fs.allocator.create(Entry);
-                entry_ptr.* = Entry{
-                    .base = name,
-                    .dir = "",
-                    .mutex = Mutex.init(),
-                    // Call "stat" lazily for performance. The "@material-ui/icons" package
-                    // contains a directory with over 11,000 entries in it and running "stat"
-                    // for each entry was a big performance issue for that package.
-                    .need_stat = true,
-                    .cache = Entry.Cache{
-                        .symlink = if (entry.kind == std.fs.Dir.Entry.Kind.SymLink) (try fs.allocator.dupe(u8, name)) else "",
-                        .kind = _kind,
-                    },
-                };
-
-                try dir.data.put(name, entry_ptr);
+                try dir.addEntry(_entry);
             }
 
             return dir;
@@ -407,7 +441,7 @@ pub const FileSystem = struct {
                 fs.entries_mutex.lock();
                 defer fs.entries_mutex.unlock();
                 var get_or_put_result = try fs.entries.getOrPut(dir);
-                var opt = try fs.entries.put(null, false, &get_or_put_result, EntriesOption{
+                var opt = try fs.entries.put(&get_or_put_result, EntriesOption{
                     .err = DirEntry.Err{ .original_err = err, .canonical_error = err },
                 });
 
@@ -422,7 +456,8 @@ pub const FileSystem = struct {
 
         threadlocal var temp_entries_option: EntriesOption = undefined;
 
-        pub fn readDirectory(fs: *RealFS, dir: string, _handle: ?std.fs.Dir, recursive: bool) !*EntriesOption {
+        pub fn readDirectory(fs: *RealFS, _dir: string, _handle: ?std.fs.Dir, recursive: bool) !*EntriesOption {
+            var dir = _dir;
             var cache_result: ?allocators.Result = null;
 
             if (!fs.do_not_cache_entries) {
@@ -446,6 +481,11 @@ pub const FileSystem = struct {
                 }
             }
 
+            // if we get this far, it's a real directory, so we can just store the dir name.
+            if (_handle == null) {
+                dir = try FilenameStore.instance.append(_dir);
+            }
+
             // Cache miss: read the directory entries
             const entries = fs.readdir(
                 dir,
@@ -454,21 +494,22 @@ pub const FileSystem = struct {
                 return fs.readDirectoryError(dir, err) catch unreachable;
             };
 
-            if (fs.watcher) |*watcher| {
-                fs.watcher_mutex.lock();
-                defer fs.watcher_mutex.unlock();
-                var _entries = entries.data.items();
-                const names = try fs.allocator.alloc([]const u8, _entries.len);
-                for (_entries) |entry, i| {
-                    names[i] = try fs.allocator.dupe(u8, entry.key);
-                }
-                strings.sortAsc(names);
+            // if (fs.watcher) |*watcher| {
+            //     fs.watcher_mutex.lock();
+            //     defer fs.watcher_mutex.unlock();
+            //     var _entries = watcher.iterator();
+            //     const names = try fs.allocator.alloc([]const u8, _entries.len);
+            //     for (_entries) |entry, i| {
+            //         names[i] = try fs.allocator.dupe(u8, entry.key);
+            //     }
+            //     strings.sortAsc(names);
+
+            //     try watcher.put(
+            //         try fs.allocator.dupe(u8, dir),
+            //         WatchData{ .dir_entries = names, .state = .dir_has_entries },
+            //     );
+            // }
 
-                try watcher.put(
-                    try fs.allocator.dupe(u8, dir),
-                    WatchData{ .dir_entries = names, .state = .dir_has_entries },
-                );
-            }
             if (!fs.do_not_cache_entries) {
                 fs.entries_mutex.lock();
                 defer fs.entries_mutex.unlock();
@@ -476,14 +517,10 @@ pub const FileSystem = struct {
                     .entries = entries,
                 };
 
-                var entries_ptr = try fs.entries.put(dir, true, &cache_result.?, result);
-                const dir_key = fs.entries.keyAtIndex(cache_result.?.index) orelse unreachable;
-                entries_ptr.entries.updateDir(dir_key);
-                return entries_ptr;
+                return try fs.entries.put(&cache_result.?, result);
             }
 
             temp_entries_option = EntriesOption{ .entries = entries };
-            temp_entries_option.entries.updateDir(try fs.allocator.dupe(u8, dir));
 
             return &temp_entries_option;
         }
@@ -532,8 +569,7 @@ pub const FileSystem = struct {
         pub fn kind(fs: *RealFS, _dir: string, base: string) !Entry.Cache {
             var dir = _dir;
             var combo = [2]string{ dir, base };
-            var entry_path = try std.fs.path.join(fs.allocator, &combo);
-            defer fs.allocator.free(entry_path);
+            var entry_path = path_handler.normalizeAndJoinString(fs.cwd, &combo, .auto);
 
             fs.limiter.before();
             defer fs.limiter.after();
@@ -544,7 +580,7 @@ pub const FileSystem = struct {
 
             var _kind = stat.kind;
             var cache = Entry.Cache{ .kind = Entry.Kind.file, .symlink = "" };
-            var symlink: []u8 = &([_]u8{});
+            var symlink: []const u8 = "";
             if (_kind == .SymLink) {
                 // windows has a max filepath of 255 chars
                 // we give it a little longer for other platforms
@@ -554,15 +590,13 @@ pub const FileSystem = struct {
                 var links_walked: u8 = 0;
 
                 while (links_walked < 255) : (links_walked += 1) {
-                    var link = try std.os.readlink(symlink, out_slice);
+                    var link: string = try std.os.readlink(symlink, out_slice);
 
                     if (!std.fs.path.isAbsolute(link)) {
                         combo[0] = dir;
                         combo[1] = link;
-                        if (link.ptr != &out_buffer) {
-                            fs.allocator.free(link);
-                        }
-                        link = std.fs.path.join(fs.allocator, &combo) catch return cache;
+
+                        link = path_handler.normalizeAndJoinStringBuf(fs.cwd, out_slice, &combo, .auto);
                     }
                     // TODO: do we need to clean the path?
                     symlink = link;
@@ -590,7 +624,9 @@ pub const FileSystem = struct {
             } else {
                 cache.kind = .file;
             }
-            cache.symlink = symlink;
+            if (symlink.len > 0) {
+                cache.symlink = try fs.allocator.dupe(u8, symlink);
+            }
 
             return cache;
         }
diff --git a/src/global.zig b/src/global.zig
index 5a48d1b9c..acd9bc0a7 100644
--- a/src/global.zig
+++ b/src/global.zig
@@ -1,6 +1,7 @@
 const std = @import("std");
 pub usingnamespace @import("strings.zig");
 
+pub const C = @import("c.zig");
 pub const BuildTarget = enum { native, wasm, wasi };
 pub const build_target: BuildTarget = comptime {
     if (std.Target.current.isWasm() and std.Target.current.getOsTag() == .wasi) {
@@ -16,6 +17,9 @@ pub const isWasm = build_target == .wasm;
 pub const isNative = build_target == .native;
 pub const isWasi = build_target == .wasi;
 pub const isBrowser = !isWasi and isWasm;
+pub const isWindows = std.Target.current.os.tag == .windows;
+
+pub const enableTracing = true;
 
 pub const isDebug = std.builtin.Mode.Debug == std.builtin.mode;
 
diff --git a/src/js_ast.zig b/src/js_ast.zig
index ee6e35729..bd2655289 100644
--- a/src/js_ast.zig
+++ b/src/js_ast.zig
@@ -318,7 +318,7 @@ pub const G = struct {
     pub const Comment = struct { loc: logger.Loc, text: string };
 
     pub const Property = struct {
-        ts_decorators: ExprNodeList = &([_]Expr{}),
+        ts_decorators: ExprNodeList = &([_]ExprNodeIndex{}),
         // Key is optional for spread
         key: ?ExprNodeIndex = null,
 
diff --git a/src/options.zig b/src/options.zig
index 6dd6ddbae..9d416ad66 100644
--- a/src/options.zig
+++ b/src/options.zig
@@ -343,8 +343,8 @@ pub const BundleOptions = struct {
                 allocator,
                 resolved_defines,
             ),
-            .output_dir = try std.fs.path.join(allocator, &output_dir_parts),
             .loaders = loaders,
+            .output_dir = try fs.joinAlloc(allocator, &output_dir_parts),
             .write = transform.write orelse false,
             .external = ExternalModules.init(allocator, &fs.fs, fs.top_level_dir, transform.external, log),
             .entry_points = transform.entry_points,
diff --git a/src/resolver/resolver.zig b/src/resolver/resolver.zig
index fd83656de..1fcbe99cb 100644
--- a/src/resolver/resolver.zig
+++ b/src/resolver/resolver.zig
@@ -28,7 +28,7 @@ pub const SideEffectsData = struct {
 };
 
 pub const DirInfo = struct {
-    pub const Index = u32;
+    pub const Index = allocators.IndexType;
 
     // These objects are immutable, so we can just point to the parent directory
     // and avoid having to lock the cache again
@@ -39,12 +39,24 @@ pub const DirInfo = struct {
     enclosing_browser_scope: Index = allocators.NotFound,
 
     abs_path: string = "",
-    entries: Fs.FileSystem.DirEntry = undefined,
+    entries: Index = undefined,
     has_node_modules: bool = false, // Is there a "node_modules" subdirectory?
     package_json: ?*PackageJSON = null, // Is there a "package.json" file?
     tsconfig_json: ?*TSConfigJSON = null, // Is there a "tsconfig.json" file in this directory or a parent directory?
     abs_real_path: string = "", // If non-empty, this is the real absolute path resolving any symlinks
 
+    pub fn getEntries(dirinfo: *DirInfo) ?*Fs.FileSystem.DirEntry {
+        var entries_ptr = Fs.FileSystem.instance.fs.entries.atIndex(dirinfo.entries) orelse return null;
+        switch (entries_ptr.*) {
+            .entries => |entr| {
+                return &entries_ptr.entries;
+            },
+            .err => {
+                return null;
+            },
+        }
+    }
+
     pub fn getParent(i: *DirInfo) ?*DirInfo {
         return HashMap.instance.atIndex(i.parent);
     }
@@ -57,7 +69,7 @@ pub const DirInfo = struct {
     // 2. Don't expect a provided key to exist after it's queried
     // 3. Store whether a directory has been queried and whether that query was successful.
     // 4. Allocate onto the https://en.wikipedia.org/wiki/.bss#BSS_in_C instead of the heap, so we can avoid memory leaks
-    pub const HashMap = allocators.BSSMap(DirInfo, 1024, true, 128);
+    pub const HashMap = allocators.BSSMap(DirInfo, Fs.Preallocate.Counts.dir_entry, false, 128);
 };
 pub const TemporaryBuffer = struct {
     pub threadlocal var ExtensionPathBuf = std.mem.zeroes([512]u8);
@@ -73,6 +85,7 @@ pub const Resolver = struct {
     allocator: *std.mem.Allocator,
 
     debug_logs: ?DebugLogs = null,
+    elapsed: i128 = 0, // tracing
 
     caches: cache.Cache.Set,
 
@@ -291,8 +304,17 @@ pub const Resolver = struct {
             }
         }
     }
+    var tracing_start: i128 = if (enableTracing) 0 else undefined;
 
     pub fn resolve(r: *Resolver, source_dir: string, import_path: string, kind: ast.ImportKind) !?Result {
+        if (enableTracing) {
+            tracing_start = std.time.nanoTimestamp();
+        }
+        defer {
+            if (enableTracing) {
+                r.elapsed += std.time.nanoTimestamp() - tracing_start;
+            }
+        }
         if (r.log.level == .verbose) {
             if (r.debug_logs != null) {
                 r.debug_logs.?.deinit();
@@ -740,34 +762,210 @@ pub const Resolver = struct {
         return path[0] != '/' and !strings.startsWith(path, "./") and !strings.startsWith(path, "../") and !strings.eql(path, ".") and !strings.eql(path, "..");
     }
 
+    pub const DirEntryResolveQueueItem = struct { result: allocators.Result, unsafe_path: string };
+    threadlocal var _dir_entry_paths_to_resolve: [256]DirEntryResolveQueueItem = undefined;
+    threadlocal var _open_dirs: [256]std.fs.Dir = undefined;
+
     fn dirInfoCached(r: *Resolver, path: string) !?*DirInfo {
-        var dir_info_entry = try r.dir_cache.getOrPut(path);
+        const top_result = try r.dir_cache.getOrPut(path);
+        if (top_result.status != .unknown) {
+            return r.dir_cache.atIndex(top_result.index);
+        }
 
-        var ptr = try r.dirInfoCachedGetOrPut(path, &dir_info_entry);
-        return ptr;
-    }
+        var i: i32 = 1;
+        _dir_entry_paths_to_resolve[0] = (DirEntryResolveQueueItem{ .result = top_result, .unsafe_path = path });
+        var top = path;
+        var top_parent: allocators.Result = allocators.Result{
+            .index = allocators.NotFound,
+            .hash = 0,
+            .status = .not_found,
+        };
+        const root_path = if (isWindows) std.fs.path.diskDesignator(path) else "/";
 
-    fn dirInfoCachedGetOrPut(r: *Resolver, path: string, dir_info_entry: *allocators.Result) !?*DirInfo {
-        switch (dir_info_entry.status) {
-            .unknown => {
-                return try r.dirInfoUncached(path, dir_info_entry);
-            },
-            .not_found => {
-                return null;
-            },
-            .exists => {
-                return r.dir_cache.atIndex(dir_info_entry.index);
-            },
+        while (std.fs.path.dirname(top)) |_top| {
+            var result = try r.dir_cache.getOrPut(_top);
+            if (result.status != .unknown) {
+                top_parent = result;
+                break;
+            }
+            _dir_entry_paths_to_resolve[@intCast(usize, i)] = DirEntryResolveQueueItem{
+                .unsafe_path = _top,
+                .result = result,
+            };
+            i += 1;
+            top = _top;
         }
-        // if (__entry.found_existing) {
-        //     return if (__entry.entry.value == DirInfo.NotFound) null else __entry.entry.value;
-        // }
 
-        // __entry.entry.value = DirInfo.NotFound;
+        if (std.fs.path.dirname(top) == null and !strings.eql(top, root_path)) {
+            var result = try r.dir_cache.getOrPut(root_path);
+            if (result.status != .unknown) {
+                top_parent = result;
+            } else {
+                _dir_entry_paths_to_resolve[@intCast(usize, i)] = DirEntryResolveQueueItem{
+                    .unsafe_path = root_path,
+                    .result = result,
+                };
+                i += 1;
+                top = root_path;
+            }
+        }
+
+        var queue_slice: []DirEntryResolveQueueItem = _dir_entry_paths_to_resolve[0..@intCast(usize, i)];
+        std.debug.assert(queue_slice.len > 0);
+        var open_dir_count: usize = 0;
+
+        // When this function halts, any item not processed means it's not found.
+        defer {
+
+            // Anything
+            if (open_dir_count > 0) {
+                var open_dirs: []std.fs.Dir = _open_dirs[0..open_dir_count];
+                for (open_dirs) |*open_dir| {
+                    open_dir.close();
+                }
+            }
+        }
+
+        var rfs: *Fs.FileSystem.RealFS = &r.fs.fs;
+
+        rfs.entries_mutex.lock();
+        defer rfs.entries_mutex.unlock();
+
+        // We want to walk in a straight line from the topmost directory to the desired directory
+        // For each directory we visit, we get the entries, but not traverse into child directories
+        // (unless those child directores are in the queue)
+        // Going top-down rather than bottom-up should have best performance because we can use
+        // the file handle from the parent directory to open the child directory
+        // It's important that we walk in precisely a straight line
+        // For example
+        // "/home/jarred/Code/node_modules/react/cjs/react.development.js"
+        //       ^
+        // If we start there, we will traverse all of /home/jarred, including e.g. /home/jarred/Downloads
+        // which is completely irrelevant.
+
+        // After much experimentation, fts_open is not the fastest way. fts actually just uses readdir!!
+        var _safe_path: ?string = null;
+
+        // Start at the top.
+        while (queue_slice.len > 0) {
+            var queue_top = queue_slice[queue_slice.len - 1];
+            defer top_parent = queue_top.result;
+            queue_slice.len -= 1;
+
+            var _open_dir: anyerror!std.fs.Dir = undefined;
+            if (open_dir_count > 0) {
+                _open_dir = _open_dirs[open_dir_count - 1].openDir(std.fs.path.basename(queue_top.unsafe_path), .{ .iterate = true });
+            } else {
+                _open_dir = std.fs.openDirAbsolute(queue_top.unsafe_path, .{ .iterate = true });
+            }
+
+            const open_dir = _open_dir catch |err| {
+                switch (err) {
+                    error.EACCESS => {},
+
+                    // Ignore "ENOTDIR" here so that calling "ReadDirectory" on a file behaves
+                    // as if there is nothing there at all instead of causing an error due to
+                    // the directory actually being a file. This is a workaround for situations
+                    // where people try to import from a path containing a file as a parent
+                    // directory. The "pnpm" package manager generates a faulty "NODE_PATH"
+                    // list which contains such paths and treating them as missing means we just
+                    // ignore them during path resolution.
+                    error.ENOENT,
+                    error.ENOTDIR,
+                    error.IsDir,
+                    error.NotDir,
+                    error.FileNotFound,
+                    => {
+                        return null;
+                    },
+
+                    else => {
+                        var cached_dir_entry_result = rfs.entries.getOrPut(queue_top.unsafe_path) catch unreachable;
+                        r.dir_cache.markNotFound(queue_top.result);
+                        rfs.entries.markNotFound(cached_dir_entry_result);
+                        const pretty = r.prettyPath(Path.init(queue_top.unsafe_path));
+
+                        r.log.addErrorFmt(
+                            null,
+                            logger.Loc{},
+                            r.allocator,
+                            "Cannot read directory \"{s}\": {s}",
+                            .{
+                                pretty,
+                                @errorName(err),
+                            },
+                        ) catch {};
+                    },
+                }
+
+                return null;
+            };
+
+            // these objects mostly just wrap the file descriptor, so it's fine to keep it.
+            _open_dirs[open_dir_count] = open_dir;
+            open_dir_count += 1;
 
-        // try r.dirInfoUncached(path);
-        // const entry = r.dir_cache.get(path) orelse unreachable;
-        // return if (__entry.entry.value == DirInfo.NotFound) null else entry;
+            if (_safe_path == null) {
+                // Now that we've opened the topmost directory successfully, it's reasonable to store the slice.
+                _safe_path = try r.fs.dirname_store.append(path);
+            }
+            const safe_path = _safe_path.?;
+
+            var dir_path_i = std.mem.indexOf(u8, safe_path, queue_top.unsafe_path) orelse unreachable;
+            const dir_path = safe_path[dir_path_i .. dir_path_i + queue_top.unsafe_path.len];
+
+            var dir_iterator = open_dir.iterate();
+
+            var cached_dir_entry_result = rfs.entries.getOrPut(dir_path) catch unreachable;
+
+            var dir_entries_option: *Fs.FileSystem.RealFS.EntriesOption = undefined;
+            var has_dir_entry_result: bool = false;
+
+            if (rfs.entries.atIndex(cached_dir_entry_result.index)) |cached_entry| {
+                if (std.meta.activeTag(cached_entry.*) == .entries) {
+                    dir_entries_option = cached_entry;
+                }
+            }
+
+            if (!has_dir_entry_result) {
+                dir_entries_option = try rfs.entries.put(&cached_dir_entry_result, .{
+                    .entries = Fs.FileSystem.DirEntry.init(dir_path, r.fs.allocator),
+                });
+                has_dir_entry_result = true;
+            }
+
+            while (try dir_iterator.next()) |_value| {
+                const value: std.fs.Dir.Entry = _value;
+                dir_entries_option.entries.addEntry(value) catch unreachable;
+            }
+
+            const dir_info = try r.dirInfoUncached(
+                dir_path,
+                dir_entries_option,
+                queue_top.result,
+                cached_dir_entry_result.index,
+                r.dir_cache.atIndex(top_parent.index),
+                top_parent.index,
+            );
+
+            var dir_info_ptr = try r.dir_cache.put(&queue_top.result, dir_info);
+
+            if (queue_slice.len == 0) {
+                return dir_info_ptr;
+
+                // Is the directory we're searching for actually a file?
+            } else if (queue_slice.len == 1) {
+                // const next_in_queue = queue_slice[0];
+                // const next_basename = std.fs.path.basename(next_in_queue.unsafe_path);
+                // if (dir_info_ptr.getEntries()) |entries| {
+                //     if (entries.get(next_basename) != null) {
+                //         return null;
+                //     }
+                // }
+            }
+        }
+
+        unreachable;
     }
 
     pub const MatchResult = struct {
@@ -1024,15 +1222,17 @@ pub const Resolver = struct {
             base[0.."index".len].* = "index".*;
             std.mem.copy(u8, base["index".len..base.len], ext);
 
-            if (dir_info.entries.get(base)) |lookup| {
-                if (lookup.entry.kind(rfs) == .file) {
-                    const parts = [_]string{ path, base };
-                    const out_buf = r.fs.joinAlloc(r.allocator, &parts) catch unreachable;
-                    if (r.debug_logs) |*debug| {
-                        debug.addNoteFmt("Found file: \"{s}\"", .{out_buf}) catch unreachable;
-                    }
+            if (dir_info.getEntries()) |entries| {
+                if (entries.get(base)) |lookup| {
+                    if (lookup.entry.kind(rfs) == .file) {
+                        const parts = [_]string{ path, base };
+                        const out_buf = r.fs.joinAlloc(r.allocator, &parts) catch unreachable;
+                        if (r.debug_logs) |*debug| {
+                            debug.addNoteFmt("Found file: \"{s}\"", .{out_buf}) catch unreachable;
+                        }
 
-                    return MatchResult{ .path_pair = .{ .primary = Path.init(out_buf) }, .diff_case = lookup.diff_case };
+                        return MatchResult{ .path_pair = .{ .primary = Path.init(out_buf) }, .diff_case = lookup.diff_case };
+                    }
                 }
             }
 
@@ -1324,113 +1524,46 @@ pub const Resolver = struct {
         return null;
     }
 
-    fn dirInfoUncached(r: *Resolver, unsafe_path: string, result: *allocators.Result) anyerror!?*DirInfo {
-        var rfs: *Fs.FileSystem.RealFS = &r.fs.fs;
-        var parent: ?*DirInfo = null;
-
-        var is_root = false;
-        const parent_dir = (std.fs.path.dirname(unsafe_path) orelse parent_dir_handle: {
-            is_root = true;
-            break :parent_dir_handle "/";
-        });
-
-        var parent_result: allocators.Result = allocators.Result{
-            .hash = std.math.maxInt(u64),
-            .index = allocators.NotFound,
-            .status = .unknown,
-        };
-        if (!is_root and !strings.eql(parent_dir, unsafe_path)) {
-            parent = r.dirInfoCached(parent_dir) catch null;
-
-            if (parent != null) {
-                parent_result = try r.dir_cache.getOrPut(parent_dir);
-            }
-        }
-
-        var entries: Fs.FileSystem.DirEntry = Fs.FileSystem.DirEntry.empty(unsafe_path, r.allocator);
-
-        // List the directories
-        if (!is_root) {
-            var _entries: *Fs.FileSystem.RealFS.EntriesOption = undefined;
-
-            _entries = try rfs.readDirectory(unsafe_path, null, true);
-
-            if (std.meta.activeTag(_entries.*) == .err) {
-                // Just pretend this directory is empty if we can't access it. This is the
-                // case on Unix for directories that only have the execute permission bit
-                // set. It means we will just pass through the empty directory and
-                // continue to check the directories above it, which is now node behaves.
-                switch (_entries.err.original_err) {
-                    error.EACCESS => {
-                        entries = Fs.FileSystem.DirEntry.empty(unsafe_path, r.allocator);
-                    },
+    fn dirInfoUncached(
+        r: *Resolver,
+        path: string,
+        _entries: *Fs.FileSystem.RealFS.EntriesOption,
+        _result: allocators.Result,
+        dir_entry_index: allocators.IndexType,
+        parent: ?*DirInfo,
+        parent_index: allocators.IndexType,
+    ) anyerror!DirInfo {
+        var result = _result;
 
-                    // Ignore "ENOTDIR" here so that calling "ReadDirectory" on a file behaves
-                    // as if there is nothing there at all instead of causing an error due to
-                    // the directory actually being a file. This is a workaround for situations
-                    // where people try to import from a path containing a file as a parent
-                    // directory. The "pnpm" package manager generates a faulty "NODE_PATH"
-                    // list which contains such paths and treating them as missing means we just
-                    // ignore them during path resolution.
-                    error.ENOENT,
-                    error.ENOTDIR,
-                    error.IsDir,
-                    => {
-                        entries = Fs.FileSystem.DirEntry.empty(unsafe_path, r.allocator);
-                    },
-                    else => {
-                        const pretty = r.prettyPath(Path.init(unsafe_path));
-                        result.status = .not_found;
-                        r.log.addErrorFmt(
-                            null,
-                            logger.Loc{},
-                            r.allocator,
-                            "Cannot read directory \"{s}\": {s}",
-                            .{
-                                pretty,
-                                @errorName(_entries.err.original_err),
-                            },
-                        ) catch {};
-                        r.dir_cache.markNotFound(result.*);
-                        return null;
-                    },
-                }
-            } else {
-                entries = _entries.entries;
-            }
-        }
+        var rfs: *Fs.FileSystem.RealFS = &r.fs.fs;
+        var entries = _entries.entries;
 
-        var info = dir_info_getter: {
-            var _info = DirInfo{
-                .abs_path = "",
-                .parent = parent_result.index,
-                .entries = entries,
-            };
-            result.status = .exists;
-            var __info = try r.dir_cache.put(unsafe_path, true, result, _info);
-            __info.abs_path = r.dir_cache.keyAtIndex(result.index).?;
-            break :dir_info_getter __info;
+        var info = DirInfo{
+            .abs_path = path,
+            .parent = parent_index,
+            .entries = dir_entry_index,
         };
 
-        const path = info.abs_path;
-
         // A "node_modules" directory isn't allowed to directly contain another "node_modules" directory
         var base = std.fs.path.basename(path);
+        // if (entries != null) {
         if (!strings.eqlComptime(base, "node_modules")) {
             if (entries.get("node_modules")) |entry| {
                 // the catch might be wrong!
                 info.has_node_modules = (entry.entry.kind(rfs)) == .dir;
             }
         }
+        // }
+
+        if (parent != null) {
 
-        if (parent_result.status != .unknown) {
             // Propagate the browser scope into child directories
-            if (parent) |parent_info| {
-                info.enclosing_browser_scope = parent_info.enclosing_browser_scope;
+            info.enclosing_browser_scope = parent.?.enclosing_browser_scope;
 
-                // Make sure "absRealPath" is the real path of the directory (resolving any symlinks)
-                if (!r.opts.preserve_symlinks) {
-                    if (parent_info.entries.get(base)) |lookup| {
+            // Make sure "absRealPath" is the real path of the directory (resolving any symlinks)
+            if (!r.opts.preserve_symlinks) {
+                if (parent.?.getEntries()) |parent_entries| {
+                    if (parent_entries.get(base)) |lookup| {
                         const entry = lookup.entry;
 
                         var symlink = entry.symlink(rfs);
@@ -1439,9 +1572,9 @@ pub const Resolver = struct {
                                 try logs.addNote(std.fmt.allocPrint(r.allocator, "Resolved symlink \"{s}\" to \"{s}\"", .{ path, symlink }) catch unreachable);
                             }
                             info.abs_real_path = symlink;
-                        } else if (parent_info.abs_real_path.len > 0) {
+                        } else if (parent.?.abs_real_path.len > 0) {
                             // this might leak a little i'm not sure
-                            const parts = [_]string{ parent_info.abs_real_path, base };
+                            const parts = [_]string{ parent.?.abs_real_path, base };
                             symlink = r.fs.joinAlloc(r.allocator, &parts) catch unreachable;
                             if (r.debug_logs) |*logs| {
                                 try logs.addNote(std.fmt.allocPrint(r.allocator, "Resolved symlink \"{s}\" to \"{s}\"", .{ path, symlink }) catch unreachable);