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Former-commit-id: 664dbf569c423280c4fb40d3114e81e0d7b9ddc3

14 files changed, 591 insertions, 89 deletions

diff --git a/esdev-fd-relative.REMOVED.git-id b/esdev-fd-relative.REMOVED.git-id
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diff --git a/esdev-nolists.REMOVED.git-id b/esdev-nolists.REMOVED.git-id
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+34dfc5e5b01bb30bf117a1e4e18520646131b19d
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diff --git a/src/ast/Wyhash.zig b/src/ast/Wyhash.zig
new file mode 100644
index 000000000..b13e267b4
--- /dev/null
+++ b/src/ast/Wyhash.zig
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2015-2021 Zig Contributors
+// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
+// The MIT license requires this copyright notice to be included in all copies
+// and substantial portions of the software.
+const std = @import("std");
+const mem = std.mem;
+
+const primes = [_]u64{
+    0xa0761d6478bd642f,
+    0xe7037ed1a0b428db,
+    0x8ebc6af09c88c6e3,
+    0x589965cc75374cc3,
+    0x1d8e4e27c47d124f,
+};
+
+fn read_bytes(comptime bytes: u8, data: []const u8) u64 {
+    const T = std.meta.Int(.unsigned, 8 * bytes);
+    return mem.readIntLittle(T, data[0..bytes]);
+}
+
+fn read_8bytes_swapped(data: []const u8) u64 {
+    return (read_bytes(4, data) << 32 | read_bytes(4, data[4..]));
+}
+
+fn mum(a: u64, b: u64) u64 {
+    var r = std.math.mulWide(u64, a, b);
+    r = (r >> 64) ^ r;
+    return @truncate(u64, r);
+}
+
+fn mix0(a: u64, b: u64, seed: u64) u64 {
+    return mum(a ^ seed ^ primes[0], b ^ seed ^ primes[1]);
+}
+
+fn mix1(a: u64, b: u64, seed: u64) u64 {
+    return mum(a ^ seed ^ primes[2], b ^ seed ^ primes[3]);
+}
+
+// Wyhash version which does not store internal state for handling partial buffers.
+// This is needed so that we can maximize the speed for the short key case, which will
+// use the non-iterative api which the public Wyhash exposes.
+pub fn WyhashGenerator(comptime ValueType: type) type {
+    return struct {
+        seed: u64,
+        msg_len: usize,
+
+        pub fn init(seed: u64) WyhashStateless {
+            return WyhashStateless{
+                .seed = seed,
+                .msg_len = 0,
+            };
+        }
+
+        fn round(self: *WyhashStateless, b: []const u8) void {
+            std.debug.assert(b.len == 32);
+
+            self.seed = mix0(
+                read_bytes(8, b[0..]),
+                read_bytes(8, b[8..]),
+                self.seed,
+            ) ^ mix1(
+                read_bytes(8, b[16..]),
+                read_bytes(8, b[24..]),
+                self.seed,
+            );
+        }
+
+        pub fn update(self: *WyhashStateless, b: []const u8) void {
+            std.debug.assert(b.len % 32 == 0);
+
+            var off: usize = 0;
+            while (off < b.len) : (off += 32) {
+                @call(.{ .modifier = .always_inline }, self.round, .{b[off .. off + 32]});
+            }
+
+            self.msg_len += b.len;
+        }
+
+        pub fn final(self: *WyhashStateless, b: []const u8) u64 {
+            std.debug.assert(b.len < 32);
+
+            const seed = self.seed;
+            const rem_len = @intCast(u5, b.len);
+            const rem_key = b[0..rem_len];
+
+            self.seed = switch (rem_len) {
+                0 => seed,
+                1 => mix0(read_bytes(1, rem_key), primes[4], seed),
+                2 => mix0(read_bytes(2, rem_key), primes[4], seed),
+                3 => mix0((read_bytes(2, rem_key) << 8) | read_bytes(1, rem_key[2..]), primes[4], seed),
+                4 => mix0(read_bytes(4, rem_key), primes[4], seed),
+                5 => mix0((read_bytes(4, rem_key) << 8) | read_bytes(1, rem_key[4..]), primes[4], seed),
+                6 => mix0((read_bytes(4, rem_key) << 16) | read_bytes(2, rem_key[4..]), primes[4], seed),
+                7 => mix0((read_bytes(4, rem_key) << 24) | (read_bytes(2, rem_key[4..]) << 8) | read_bytes(1, rem_key[6..]), primes[4], seed),
+                8 => mix0(read_8bytes_swapped(rem_key), primes[4], seed),
+                9 => mix0(read_8bytes_swapped(rem_key), read_bytes(1, rem_key[8..]), seed),
+                10 => mix0(read_8bytes_swapped(rem_key), read_bytes(2, rem_key[8..]), seed),
+                11 => mix0(read_8bytes_swapped(rem_key), (read_bytes(2, rem_key[8..]) << 8) | read_bytes(1, rem_key[10..]), seed),
+                12 => mix0(read_8bytes_swapped(rem_key), read_bytes(4, rem_key[8..]), seed),
+                13 => mix0(read_8bytes_swapped(rem_key), (read_bytes(4, rem_key[8..]) << 8) | read_bytes(1, rem_key[12..]), seed),
+                14 => mix0(read_8bytes_swapped(rem_key), (read_bytes(4, rem_key[8..]) << 16) | read_bytes(2, rem_key[12..]), seed),
+                15 => mix0(read_8bytes_swapped(rem_key), (read_bytes(4, rem_key[8..]) << 24) | (read_bytes(2, rem_key[12..]) << 8) | read_bytes(1, rem_key[14..]), seed),
+                16 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed),
+                17 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_bytes(1, rem_key[16..]), primes[4], seed),
+                18 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_bytes(2, rem_key[16..]), primes[4], seed),
+                19 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1((read_bytes(2, rem_key[16..]) << 8) | read_bytes(1, rem_key[18..]), primes[4], seed),
+                20 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_bytes(4, rem_key[16..]), primes[4], seed),
+                21 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1((read_bytes(4, rem_key[16..]) << 8) | read_bytes(1, rem_key[20..]), primes[4], seed),
+                22 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1((read_bytes(4, rem_key[16..]) << 16) | read_bytes(2, rem_key[20..]), primes[4], seed),
+                23 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1((read_bytes(4, rem_key[16..]) << 24) | (read_bytes(2, rem_key[20..]) << 8) | read_bytes(1, rem_key[22..]), primes[4], seed),
+                24 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), primes[4], seed),
+                25 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), read_bytes(1, rem_key[24..]), seed),
+                26 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), read_bytes(2, rem_key[24..]), seed),
+                27 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), (read_bytes(2, rem_key[24..]) << 8) | read_bytes(1, rem_key[26..]), seed),
+                28 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), read_bytes(4, rem_key[24..]), seed),
+                29 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), (read_bytes(4, rem_key[24..]) << 8) | read_bytes(1, rem_key[28..]), seed),
+                30 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), (read_bytes(4, rem_key[24..]) << 16) | read_bytes(2, rem_key[28..]), seed),
+                31 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), (read_bytes(4, rem_key[24..]) << 24) | (read_bytes(2, rem_key[28..]) << 8) | read_bytes(1, rem_key[30..]), seed),
+            };
+
+            self.msg_len += b.len;
+            return mum(self.seed ^ self.msg_len, primes[4]);
+        }
+
+        pub fn hash(seed: u64, value: ValueType) u64 {
+            const input = std.mem.asBytes(&value);
+            const aligned_len = @sizeOf(value) - (@sizeOf(value) % 32);
+
+            var c = WyhashStateless.init(seed);
+            @call(.{ .modifier = .always_inline }, c.update, .{input[0..aligned_len]});
+            return @call(.{ .modifier = .always_inline }, c.final, .{input[aligned_len..]});
+        }
+    };
+}
+// Wyhash version which does not store internal state for handling partial buffers.
+// This is needed so that we can maximize the speed for the short key case, which will
+// use the non-iterative api which the public Wyhash exposes.
+const WyhashStateless = struct {
+    seed: u64,
+    msg_len: usize,
+
+    pub fn init(seed: u64) WyhashStateless {
+        return WyhashStateless{
+            .seed = seed,
+            .msg_len = 0,
+        };
+    }
+
+    fn round(self: *WyhashStateless, b: []const u8) void {
+        std.debug.assert(b.len == 32);
+
+        self.seed = mix0(
+            read_bytes(8, b[0..]),
+            read_bytes(8, b[8..]),
+            self.seed,
+        ) ^ mix1(
+            read_bytes(8, b[16..]),
+            read_bytes(8, b[24..]),
+            self.seed,
+        );
+    }
+
+    pub fn update(self: *WyhashStateless, b: []const u8) void {
+        std.debug.assert(b.len % 32 == 0);
+
+        var off: usize = 0;
+        while (off < b.len) : (off += 32) {
+            @call(.{ .modifier = .always_inline }, self.round, .{b[off .. off + 32]});
+        }
+
+        self.msg_len += b.len;
+    }
+
+    pub fn final(self: *WyhashStateless, b: []const u8) u64 {
+        std.debug.assert(b.len < 32);
+
+        const seed = self.seed;
+        const rem_len = @intCast(u5, b.len);
+        const rem_key = b[0..rem_len];
+
+        self.seed = switch (rem_len) {
+            0 => seed,
+            1 => mix0(read_bytes(1, rem_key), primes[4], seed),
+            2 => mix0(read_bytes(2, rem_key), primes[4], seed),
+            3 => mix0((read_bytes(2, rem_key) << 8) | read_bytes(1, rem_key[2..]), primes[4], seed),
+            4 => mix0(read_bytes(4, rem_key), primes[4], seed),
+            5 => mix0((read_bytes(4, rem_key) << 8) | read_bytes(1, rem_key[4..]), primes[4], seed),
+            6 => mix0((read_bytes(4, rem_key) << 16) | read_bytes(2, rem_key[4..]), primes[4], seed),
+            7 => mix0((read_bytes(4, rem_key) << 24) | (read_bytes(2, rem_key[4..]) << 8) | read_bytes(1, rem_key[6..]), primes[4], seed),
+            8 => mix0(read_8bytes_swapped(rem_key), primes[4], seed),
+            9 => mix0(read_8bytes_swapped(rem_key), read_bytes(1, rem_key[8..]), seed),
+            10 => mix0(read_8bytes_swapped(rem_key), read_bytes(2, rem_key[8..]), seed),
+            11 => mix0(read_8bytes_swapped(rem_key), (read_bytes(2, rem_key[8..]) << 8) | read_bytes(1, rem_key[10..]), seed),
+            12 => mix0(read_8bytes_swapped(rem_key), read_bytes(4, rem_key[8..]), seed),
+            13 => mix0(read_8bytes_swapped(rem_key), (read_bytes(4, rem_key[8..]) << 8) | read_bytes(1, rem_key[12..]), seed),
+            14 => mix0(read_8bytes_swapped(rem_key), (read_bytes(4, rem_key[8..]) << 16) | read_bytes(2, rem_key[12..]), seed),
+            15 => mix0(read_8bytes_swapped(rem_key), (read_bytes(4, rem_key[8..]) << 24) | (read_bytes(2, rem_key[12..]) << 8) | read_bytes(1, rem_key[14..]), seed),
+            16 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed),
+            17 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_bytes(1, rem_key[16..]), primes[4], seed),
+            18 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_bytes(2, rem_key[16..]), primes[4], seed),
+            19 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1((read_bytes(2, rem_key[16..]) << 8) | read_bytes(1, rem_key[18..]), primes[4], seed),
+            20 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_bytes(4, rem_key[16..]), primes[4], seed),
+            21 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1((read_bytes(4, rem_key[16..]) << 8) | read_bytes(1, rem_key[20..]), primes[4], seed),
+            22 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1((read_bytes(4, rem_key[16..]) << 16) | read_bytes(2, rem_key[20..]), primes[4], seed),
+            23 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1((read_bytes(4, rem_key[16..]) << 24) | (read_bytes(2, rem_key[20..]) << 8) | read_bytes(1, rem_key[22..]), primes[4], seed),
+            24 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), primes[4], seed),
+            25 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), read_bytes(1, rem_key[24..]), seed),
+            26 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), read_bytes(2, rem_key[24..]), seed),
+            27 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), (read_bytes(2, rem_key[24..]) << 8) | read_bytes(1, rem_key[26..]), seed),
+            28 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), read_bytes(4, rem_key[24..]), seed),
+            29 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), (read_bytes(4, rem_key[24..]) << 8) | read_bytes(1, rem_key[28..]), seed),
+            30 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), (read_bytes(4, rem_key[24..]) << 16) | read_bytes(2, rem_key[28..]), seed),
+            31 => mix0(read_8bytes_swapped(rem_key), read_8bytes_swapped(rem_key[8..]), seed) ^ mix1(read_8bytes_swapped(rem_key[16..]), (read_bytes(4, rem_key[24..]) << 24) | (read_bytes(2, rem_key[28..]) << 8) | read_bytes(1, rem_key[30..]), seed),
+        };
+
+        self.msg_len += b.len;
+        return mum(self.seed ^ self.msg_len, primes[4]);
+    }
+
+    pub fn hash(seed: u64, input: []const u8) u64 {
+        const aligned_len = input.len - (input.len % 32);
+
+        var c = WyhashStateless.init(seed);
+        @call(.{ .modifier = .always_inline }, c.update, .{input[0..aligned_len]});
+        return @call(.{ .modifier = .always_inline }, c.final, .{input[aligned_len..]});
+    }
+};
+
+/// Fast non-cryptographic 64bit hash function.
+/// See https://github.com/wangyi-fudan/wyhash
+pub const Wyhash = struct {
+    state: WyhashStateless,
+
+    buf: [32]u8,
+    buf_len: usize,
+
+    pub fn init(seed: u64) Wyhash {
+        return Wyhash{
+            .state = WyhashStateless.init(seed),
+            .buf = undefined,
+            .buf_len = 0,
+        };
+    }
+
+    pub fn update(self: *Wyhash, b: []const u8) void {
+        var off: usize = 0;
+
+        if (self.buf_len != 0 and self.buf_len + b.len >= 32) {
+            off += 32 - self.buf_len;
+            mem.copy(u8, self.buf[self.buf_len..], b[0..off]);
+            self.state.update(self.buf[0..]);
+            self.buf_len = 0;
+        }
+
+        const remain_len = b.len - off;
+        const aligned_len = remain_len - (remain_len % 32);
+        self.state.update(b[off .. off + aligned_len]);
+
+        mem.copy(u8, self.buf[self.buf_len..], b[off + aligned_len ..]);
+        self.buf_len += @intCast(u8, b[off + aligned_len ..].len);
+    }
+
+    pub fn final(self: *Wyhash) u64 {
+        const seed = self.state.seed;
+        const rem_len = @intCast(u5, self.buf_len);
+        const rem_key = self.buf[0..self.buf_len];
+
+        return self.state.final(rem_key);
+    }
+
+    pub fn hash(seed: u64, input: []const u8) u64 {
+        return WyhashStateless.hash(seed, input);
+    }
+};
+
+const expectEqual = std.testing.expectEqual;
+
+test "test vectors" {
+    const hash = Wyhash.hash;
+
+    try expectEqual(hash(0, ""), 0x0);
+    try expectEqual(hash(1, "a"), 0xbed235177f41d328);
+    try expectEqual(hash(2, "abc"), 0xbe348debe59b27c3);
+    try expectEqual(hash(3, "message digest"), 0x37320f657213a290);
+    try expectEqual(hash(4, "abcdefghijklmnopqrstuvwxyz"), 0xd0b270e1d8a7019c);
+    try expectEqual(hash(5, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"), 0x602a1894d3bbfe7f);
+    try expectEqual(hash(6, "12345678901234567890123456789012345678901234567890123456789012345678901234567890"), 0x829e9c148b75970e);
+}
+
+test "test vectors streaming" {
+    var wh = Wyhash.init(5);
+    for ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") |e| {
+        wh.update(mem.asBytes(&e));
+    }
+    try expectEqual(wh.final(), 0x602a1894d3bbfe7f);
+
+    const pattern = "1234567890";
+    const count = 8;
+    const result = 0x829e9c148b75970e;
+    try expectEqual(Wyhash.hash(6, pattern ** 8), result);
+
+    wh = Wyhash.init(6);
+    var i: u32 = 0;
+    while (i < count) : (i += 1) {
+        wh.update(pattern);
+    }
+    try expectEqual(wh.final(), result);
+}
+
+test "iterative non-divisible update" {
+    var buf: [8192]u8 = undefined;
+    for (buf) |*e, i| {
+        e.* = @truncate(u8, i);
+    }
+
+    const seed = 0x128dad08f;
+
+    var end: usize = 32;
+    while (end < buf.len) : (end += 32) {
+        const non_iterative_hash = Wyhash.hash(seed, buf[0..end]);
+
+        var wy = Wyhash.init(seed);
+        var i: usize = 0;
+        while (i < end) : (i += 33) {
+            wy.update(buf[i..std.math.min(i + 33, end)]);
+        }
+        const iterative_hash = wy.final();
+
+        try std.testing.expectEqual(iterative_hash, non_iterative_hash);
+    }
+}
diff --git a/src/ast/base.zig b/src/ast/base.zig
index cf08ca780..3f10beb37 100644
--- a/src/ast/base.zig
+++ b/src/ast/base.zig
@@ -27,6 +27,10 @@ pub const Ref = packed struct {
     inner_index: Int = 0,
     is_source_contents_slice: bool = false,
 
+    pub fn hash(key: Ref) u64 {
+        @compileError("Dont call");
+    }
+
     // 2 bits of padding for whatever is the parent
     pub const Int = u30;
     pub const None = Ref{
@@ -70,11 +74,11 @@ pub const RequireOrImportMeta = struct {
     exports_ref: Ref = Ref.None,
     is_wrapper_async: bool = false,
 };
-pub fn debug(comptime fmt: []const u8, args: anytype) callconv(.Inline) void {
+pub inline fn debug(comptime fmt: []const u8, args: anytype) void {
     // Output.print(fmt, args);
 }
-pub fn debugl(
+pub inline fn debugl(
     comptime fmt: []const u8,
-) callconv(.Inline) void {
+) void {
     // Output.print("{s}\n", .{fmt});
 }
diff --git a/src/bundler.zig b/src/bundler.zig
index dcb5a25c5..4d88b27f2 100644
--- a/src/bundler.zig
+++ b/src/bundler.zig
@@ -171,15 +171,20 @@ pub const Bundler = struct {
         // Run the resolver
         // Don't parse/print automatically.
         if (bundler.options.resolve_mode != .lazy) {
-            if (!bundler.resolve_results.contains(resolve_result.path_pair.primary.text)) {
-                try bundler.resolve_results.put(resolve_result.path_pair.primary.text, resolve_result);
+            var hash_key = resolve_result.path_pair.primary.text;
+
+            // Shorter hash key is faster to hash
+            if (strings.startsWith(resolve_result.path_pair.primary.text, bundler.fs.top_level_dir)) {
+                hash_key = resolve_result.path_pair.primary.text[bundler.fs.top_level_dir.len..];
+            }
+
+            if (!bundler.resolve_results.contains(hash_key)) {
+                try bundler.resolve_results.put(hash_key, resolve_result);
                 try bundler.resolve_queue.writeItem(resolve_result);
             }
         }
 
-        if (!strings.eql(import_record.path.text, resolve_result.path_pair.primary.text)) {
-            import_record.path = try bundler.generateImportPath(source_dir, resolve_result.path_pair.primary.text);
-        }
+        import_record.path = try bundler.generateImportPath(source_dir, resolve_result.path_pair.primary.text);
     }
 
     pub fn buildWithResolveResult(bundler: *Bundler, resolve_result: Resolver.Resolver.Result) !?options.OutputFile {
@@ -190,8 +195,9 @@ pub const Bundler = struct {
         // Step 1. Parse & scan
         const loader = bundler.options.loaders.get(resolve_result.path_pair.primary.name.ext) orelse .file;
         var file_path = resolve_result.path_pair.primary;
+
         file_path.pretty = relative_paths_list.append(bundler.fs.relativeTo(file_path.text)) catch unreachable;
-        var result = bundler.parse(file_path, loader) orelse return null;
+        var result = bundler.parse(file_path, loader, resolve_result.dirname_fd) orelse return null;
 
         switch (result.loader) {
             .jsx, .js, .ts, .tsx => {
@@ -304,7 +310,7 @@ 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, loader: options.Loader) ?ParseResult {
+    pub fn parse(bundler: *Bundler, path: Fs.Path, loader: options.Loader, dirname_fd: StoredFileDescriptorType) ?ParseResult {
         if (enableTracing) {
             tracing_start = std.time.nanoTimestamp();
         }
@@ -314,7 +320,7 @@ pub const Bundler = struct {
             }
         }
         var result: ParseResult = undefined;
-        const entry = bundler.resolver.caches.fs.readFile(bundler.fs, path.text) catch return null;
+        const entry = bundler.resolver.caches.fs.readFile(bundler.fs, path.text, dirname_fd) catch return null;
         const source = logger.Source.initFile(Fs.File{ .path = path, .contents = entry.contents }, bundler.allocator) catch return null;
 
         switch (loader) {
@@ -498,6 +504,11 @@ pub const Bundler = struct {
     ) !options.TransformResult {
         var bundler = try Bundler.init(allocator, log, opts);
 
+        //  100.00 µs std.fifo.LinearFifo(resolver.resolver.Result,std.fifo.LinearFifoBufferType { .Dynamic = {}}).writeItemAssumeCapacity
+        if (bundler.options.resolve_mode != .lazy) {
+            try bundler.resolve_queue.ensureUnusedCapacity(1000);
+        }
+
         var entry_points = try allocator.alloc(Resolver.Resolver.Result, bundler.options.entry_points.len);
 
         if (isDebug) {
@@ -660,6 +671,11 @@ pub const Transformer = struct {
         var arena: std.heap.ArenaAllocator = undefined;
         const use_arenas = opts.entry_points.len > 8;
 
+        js_ast.Expr.Data.Store.create(allocator);
+        js_ast.Stmt.Data.Store.create(allocator);
+
+        var ulimit: usize = Fs.FileSystem.RealFS.adjustUlimit();
+        var care_about_closing_files = !(FeatureFlags.store_file_descriptors and opts.entry_points.len * 2 < ulimit);
         for (opts.entry_points) |entry_point, i| {
             if (use_arenas) {
                 arena = std.heap.ArenaAllocator.init(allocator);
@@ -674,19 +690,23 @@ pub const Transformer = struct {
 
             var _log = logger.Log.init(allocator);
             var __log = &_log;
-            var paths = [_]string{ cwd, entry_point };
-            const absolutePath = try std.fs.path.resolve(chosen_alloc, &paths);
+            const absolutePath = resolve_path.joinAbs(cwd, .auto, entry_point);
 
             const file = try std.fs.openFileAbsolute(absolutePath, std.fs.File.OpenFlags{ .read = true });
-            defer file.close();
+            defer {
+                if (care_about_closing_files) {
+                    file.close();
+                }
+            }
+
             const stat = try file.stat();
 
+            // 1 byte sentinel
             const code = try file.readToEndAlloc(allocator, stat.size);
             defer {
                 if (_log.msgs.items.len == 0) {
                     allocator.free(code);
                 }
-                chosen_alloc.free(absolutePath);
                 _log.appendTo(log) catch {};
             }
             const _file = Fs.File{ .path = Fs.Path.init(entry_point), .contents = code };
@@ -710,6 +730,8 @@ pub const Transformer = struct {
             const relative_path = resolve_path.relative(cwd, absolutePath);
             const out_path = resolve_path.joinAbs2(cwd, .auto, absolutePath, relative_path);
             try output_files.append(options.OutputFile{ .path = allocator.dupe(u8, out_path) catch continue, .contents = res.js });
+            js_ast.Expr.Data.Store.reset();
+            js_ast.Stmt.Data.Store.reset();
         }
 
         return try options.TransformResult.init(output_dir, output_files.toOwnedSlice(), log, allocator);
diff --git a/src/cache.zig b/src/cache.zig
index 22953a3a2..56a706c5c 100644
--- a/src/cache.zig
+++ b/src/cache.zig
@@ -37,6 +37,7 @@ pub const Cache = struct {
 
         pub const Entry = struct {
             contents: string,
+            fd: StoredFileDescriptorType = 0,
             // Null means its not usable
             mod_key: ?fs.FileSystem.Implementation.ModKey = null,
 
@@ -56,7 +57,7 @@ pub const Cache = struct {
             c.entries.deinit();
         }
 
-        pub fn readFile(c: *Fs, _fs: *fs.FileSystem, path: string) !Entry {
+        pub fn readFile(c: *Fs, _fs: *fs.FileSystem, path: string, dirname_fd: StoredFileDescriptorType) !Entry {
             var rfs = _fs.fs;
 
             {
@@ -67,9 +68,23 @@ pub const Cache = struct {
                 }
             }
 
+            var file_handle: std.fs.File = undefined;
+
+            if (FeatureFlags.store_file_descriptors and dirname_fd > 0) {
+                file_handle = try std.fs.Dir.openFile(std.fs.Dir{ .fd = dirname_fd }, std.fs.path.basename(path), .{ .read = true });
+            } else {
+                file_handle = try std.fs.openFileAbsolute(path, .{ .read = true });
+            }
+
+            defer {
+                if (rfs.needToCloseFiles()) {
+                    file_handle.close();
+                }
+            }
+
             // If the file's modification key hasn't changed since it was cached, assume
             // the contents of the file are also the same and skip reading the file.
-            var mod_key: ?fs.FileSystem.Implementation.ModKey = rfs.modKey(path) catch |err| handler: {
+            var mod_key: ?fs.FileSystem.Implementation.ModKey = rfs.modKeyWithFile(path, file_handle) catch |err| handler: {
                 switch (err) {
                     error.FileNotFound, error.AccessDenied => {
                         return err;
@@ -85,14 +100,14 @@ pub const Cache = struct {
 
             var file: fs.File = undefined;
             if (mod_key) |modk| {
-                file = rfs.readFile(path, modk.size) catch |err| {
+                file = rfs.readFileWithHandle(path, modk.size, file_handle) catch |err| {
                     if (isDebug) {
                         Output.printError("{s}: readFile error -- {s}", .{ path, @errorName(err) });
                     }
                     return err;
                 };
             } else {
-                file = rfs.readFile(path, null) catch |err| {
+                file = rfs.readFileWithHandle(path, null, file_handle) catch |err| {
                     if (isDebug) {
                         Output.printError("{s}: readFile error -- {s}", .{ path, @errorName(err) });
                     }
@@ -103,6 +118,7 @@ pub const Cache = struct {
             const entry = Entry{
                 .contents = file.contents,
                 .mod_key = mod_key,
+                .fd = if (FeatureFlags.store_file_descriptors) file_handle.handle else 0,
             };
 
             c.mutex.lock();
diff --git a/src/cli.zig b/src/cli.zig
index 7668fddab..002eee57a 100644
--- a/src/cli.zig
+++ b/src/cli.zig
@@ -21,6 +21,8 @@ const clap = @import("clap");
 
 const bundler = @import("bundler.zig");
 
+const fs = @import("fs.zig");
+
 pub fn constStrToU8(s: string) []u8 {
     return @intToPtr([*]u8, @ptrToInt(s.ptr))[0..s.len];
 }
@@ -319,17 +321,19 @@ pub const Cli = struct {
         var did_write = false;
 
         var writer = stdout.writer();
-
+        var open_file_limit: usize = 32;
         if (args.write) |write| {
             if (write) {
-                var open_file_limit: usize = 32;
-
                 if (std.os.getrlimit(.NOFILE)) |limit| {
                     open_file_limit = limit.cur;
                 } else |err| {}
-                const do_we_need_to_close = open_file_limit > result.output_files.len * 2;
+
                 did_write = true;
                 var root_dir = try std.fs.openDirAbsolute(result.outbase, std.fs.Dir.OpenDirOptions{});
+                // On posix, file handles automatically close on process exit by the OS
+                // Closing files shows up in profiling.
+                // So don't do that unless we actually need to.
+                const do_we_need_to_close = !FeatureFlags.store_file_descriptors or (@intCast(usize, root_dir.fd) + open_file_limit) < result.output_files.len;
 
                 defer {
                     if (do_we_need_to_close) {
@@ -390,6 +394,11 @@ pub const Cli = struct {
         if (isDebug) {
             Output.println("Expr count: {d}", .{js_ast.Expr.icount});
             Output.println("Stmt count: {d}", .{js_ast.Stmt.icount});
+
+            Output.println("File Descriptors: {d} / {d}", .{
+                fs.FileSystem.max_fd,
+                open_file_limit,
+            });
         }
 
         if (!did_write) {
@@ -415,8 +424,10 @@ pub const Cli = struct {
         const duration = std.time.nanoTimestamp() - start_time;
 
         if (did_write and duration < @as(i128, @as(i128, std.time.ns_per_s) * @as(i128, 2))) {
-            var elapsed = @divFloor(duration, @as(i128, std.time.ns_per_ms));
+            var elapsed = @divExact(duration, @as(i128, std.time.ns_per_ms));
             try writer.print("\nCompleted in {d}ms", .{elapsed});
         }
+
+        std.os.exit(0);
     }
 };
diff --git a/src/fs.zig b/src/fs.zig
index 32961d171..d35eacff3 100644
--- a/src/fs.zig
+++ b/src/fs.zig
@@ -28,6 +28,17 @@ pub const FileSystem = struct {
 
     dirname_store: *DirnameStore,
     filename_store: *FilenameStore,
+
+    pub var max_fd: FileDescriptorType = 0;
+
+    pub inline fn setMaxFd(fd: anytype) void {
+        if (!FeatureFlags.store_file_descriptors) {
+            return;
+        }
+
+        max_fd = std.math.max(fd, max_fd);
+    }
+
     pub var instance: FileSystem = undefined;
 
     pub const DirnameStore = allocators.BSSStringList(Preallocate.Counts.dir_entry, 256);
@@ -73,6 +84,7 @@ pub const FileSystem = struct {
         pub const EntryMap = std.StringHashMap(EntryStore.ListIndex);
         pub const EntryStore = allocators.BSSList(Entry, Preallocate.Counts.files);
         dir: string,
+        fd: StoredFileDescriptorType = 0,
         data: EntryMap,
 
         pub fn addEntry(dir: *DirEntry, entry: std.fs.Dir.Entry) !void {
@@ -153,7 +165,7 @@ pub const FileSystem = struct {
             d.data.deinit();
         }
 
-        pub fn get(entry: *DirEntry, _query: string) ?Entry.Lookup {
+        pub fn get(entry: *const DirEntry, _query: string) ?Entry.Lookup {
             if (_query.len == 0) return null;
 
             var end: usize = 0;
@@ -354,6 +366,17 @@ pub const FileSystem = struct {
         file_limit: usize = 32,
         file_quota: usize = 32,
 
+        pub fn needToCloseFiles(rfs: *const RealFS) bool {
+            // On Windows, we must always close open file handles
+            // Windows locks files
+            if (!FeatureFlags.store_file_descriptors) {
+                return true;
+            }
+
+            // If we're not near the max amount of open files, don't worry about it.
+            return !(rfs.file_limit > 254 and rfs.file_limit > (FileSystem.max_fd + 1) * 2);
+        }
+
         // Always try to max out how many files we can keep open
         pub fn adjustUlimit() usize {
             var limit = std.os.getrlimit(.NOFILE) catch return 32;
@@ -375,7 +398,7 @@ pub const FileSystem = struct {
                 .cwd = cwd,
                 .file_limit = file_limit,
                 .file_quota = file_limit,
-                .limiter = Limiter.init(allocator),
+                .limiter = Limiter.init(allocator, file_limit),
                 .watcher = if (enable_watcher) std.StringHashMap(WatchData).init(allocator) else null,
             };
         }
@@ -389,9 +412,7 @@ pub const FileSystem = struct {
             mtime: i128 = 0,
             mode: std.fs.File.Mode = 0,
 
-            pub fn generate(fs: *RealFS, path: string) anyerror!ModKey {
-                var file = try std.fs.openFileAbsolute(path, std.fs.File.OpenFlags{ .read = true });
-                defer file.close();
+            pub fn generate(fs: *RealFS, path: string, file: std.fs.File) anyerror!ModKey {
                 const stat = try file.stat();
 
                 const seconds = @divTrunc(stat.mtime, @as(@TypeOf(stat.mtime), std.time.ns_per_s));
@@ -437,11 +458,8 @@ pub const FileSystem = struct {
             }
         }
 
-        pub fn modKey(fs: *RealFS, path: string) anyerror!ModKey {
-            fs.limiter.before();
-            defer fs.limiter.after();
-
-            const key = ModKey.generate(fs, path) catch |err| {
+        pub fn modKeyWithFile(fs: *RealFS, path: string, file: anytype) anyerror!ModKey {
+            const key = ModKey.generate(fs, path, file) catch |err| {
                 fs.modKeyError(path, err);
                 return err;
             };
@@ -457,6 +475,18 @@ pub const FileSystem = struct {
             return key;
         }
 
+        pub fn modKey(fs: *RealFS, path: string) anyerror!ModKey {
+            fs.limiter.before();
+            defer fs.limiter.after();
+            var file = try std.fs.openFileAbsolute(path, std.fs.File.OpenFlags{ .read = true });
+            defer {
+                if (fs.needToCloseFiles()) {
+                    file.close();
+                }
+            }
+            return try fs.modKeyWithFile(path, file);
+        }
+
         pub const WatchData = struct {
             dir_entries: []string = &([_]string{}),
             file_contents: string = "",
@@ -493,9 +523,9 @@ pub const FileSystem = struct {
         // Limit the number of files open simultaneously to avoid ulimit issues
         pub const Limiter = struct {
             semaphore: Semaphore,
-            pub fn init(allocator: *std.mem.Allocator) Limiter {
+            pub fn init(allocator: *std.mem.Allocator, limit: usize) Limiter {
                 return Limiter{
-                    .semaphore = Semaphore.init(32),
+                    .semaphore = Semaphore.init(limit),
                     // .counter = std.atomic.Int(u8).init(0),
                     // .lock = std.Thread.Mutex.init(),
                 };
@@ -532,6 +562,12 @@ pub const FileSystem = struct {
             var iter: std.fs.Dir.Iterator = handle.iterate();
             var dir = DirEntry.init(_dir, fs.allocator);
             errdefer dir.deinit();
+
+            if (FeatureFlags.store_file_descriptors) {
+                FileSystem.setMaxFd(handle.fd);
+                dir.fd = handle.fd;
+            }
+
             while (try iter.next()) |_entry| {
                 try dir.addEntry(_entry);
             }
@@ -585,7 +621,7 @@ pub const FileSystem = struct {
             var handle = _handle orelse try fs.openDir(dir);
 
             defer {
-                if (_handle == null) {
+                if (_handle == null and fs.needToCloseFiles()) {
                     handle.close();
                 }
             }
@@ -596,7 +632,7 @@ pub const FileSystem = struct {
             }
 
             // Cache miss: read the directory entries
-            const entries = fs.readdir(
+            var entries = fs.readdir(
                 dir,
                 handle,
             ) catch |err| {
@@ -643,15 +679,8 @@ pub const FileSystem = struct {
             }
         }
 
-        pub fn readFile(fs: *RealFS, path: string, _size: ?usize) !File {
-            fs.limiter.before();
-            defer fs.limiter.after();
-
-            const file: std.fs.File = std.fs.openFileAbsolute(path, std.fs.File.OpenFlags{ .read = true, .write = false }) catch |err| {
-                fs.readFileError(path, err);
-                return err;
-            };
-            defer file.close();
+        pub fn readFileWithHandle(fs: *RealFS, path: string, _size: ?usize, file: std.fs.File) !File {
+            FileSystem.setMaxFd(file.handle);
 
             // Skip the extra file.stat() call when possible
             var size = _size orelse (file.getEndPos() catch |err| {
@@ -675,6 +704,26 @@ pub const FileSystem = struct {
             return File{ .path = Path.init(path), .contents = file_contents };
         }
 
+        pub fn readFile(
+            fs: *RealFS,
+            path: string,
+            _size: ?usize,
+        ) !File {
+            fs.limiter.before();
+            defer fs.limiter.after();
+            const file: std.fs.File = std.fs.openFileAbsolute(path, std.fs.File.OpenFlags{ .read = true, .write = false }) catch |err| {
+                fs.readFileError(path, err);
+                return err;
+            };
+            defer {
+                if (fs.needToCloseFiles()) {
+                    file.close();
+                }
+            }
+
+            return try fs.readFileWithHandle(path, _size, file);
+        }
+
         pub fn kind(fs: *RealFS, _dir: string, base: string) !Entry.Cache {
             var dir = _dir;
             var combo = [2]string{ dir, base };
@@ -684,7 +733,11 @@ pub const FileSystem = struct {
             defer fs.limiter.after();
 
             const file = try std.fs.openFileAbsolute(entry_path, .{ .read = true, .write = false });
-            defer file.close();
+            defer {
+                if (fs.needToCloseFiles()) {
+                    file.close();
+                }
+            }
             var stat = try file.stat();
 
             var _kind = stat.kind;
@@ -711,6 +764,7 @@ pub const FileSystem = struct {
                     symlink = link;
 
                     const file2 = std.fs.openFileAbsolute(symlink, std.fs.File.OpenFlags{ .read = true, .write = false }) catch return cache;
+                    // These ones we always close
                     defer file2.close();
 
                     const stat2 = file2.stat() catch return cache;
@@ -756,18 +810,6 @@ pub const FileSystem = struct {
     };
 };
 
-pub const FileSystemEntry = union(FileSystemEntry.Kind) {
-    file: File,
-    directory: Directory,
-    not_found: FileNotFound,
-
-    pub const Kind = enum(u8) {
-        file,
-        directory,
-        not_found,
-    };
-};
-
 pub const Directory = struct { path: Path, contents: []string };
 pub const File = struct { path: Path, contents: string };
 
diff --git a/src/global.zig b/src/global.zig
index 81263e658..0009e1a4c 100644
--- a/src/global.zig
+++ b/src/global.zig
@@ -29,6 +29,8 @@ pub const FeatureFlags = struct {
 
     pub const print_ast = false;
     pub const disable_printing_null = false;
+
+    pub const store_file_descriptors = !isWindows and !isBrowser;
 };
 
 pub const enableTracing = true;
@@ -135,3 +137,10 @@ pub const Global = struct {
         Global.panic("Not implemented yet!!!!!", .{});
     }
 };
+
+pub const FileDescriptorType = if (isBrowser) u0 else std.os.fd_t;
+
+// When we are on a computer with an absurdly high number of max open file handles
+// such is often the case with macOS
+// As a useful optimization, we can store file descriptors and just keep them open...forever
+pub const StoredFileDescriptorType = if (isWindows or isBrowser) u0 else std.os.fd_t;
diff --git a/src/resolver/package_json.zig b/src/resolver/package_json.zig
index a9952c8b1..053e00a90 100644
--- a/src/resolver/package_json.zig
+++ b/src/resolver/package_json.zig
@@ -44,11 +44,13 @@ pub const PackageJSON = struct {
     //
     browser_map: BrowserMap,
 
-    pub fn parse(r: *resolver.Resolver, input_path: string) ?PackageJSON {
+    pub fn parse(r: *resolver.Resolver, input_path: string, dirname_fd: StoredFileDescriptorType) ?PackageJSON {
         const parts = [_]string{ input_path, "package.json" };
-        const package_json_path = r.fs.join(&parts);
 
-        const entry = r.caches.fs.readFile(r.fs, input_path) catch |err| {
+        const package_json_path_ = r.fs.abs(&parts);
+        const package_json_path = r.fs.filename_store.append(package_json_path_) catch unreachable;
+
+        const entry = r.caches.fs.readFile(r.fs, package_json_path, dirname_fd) catch |err| {
             if (err != error.IsDir) {
                 r.log.addErrorFmt(null, logger.Loc.Empty, r.allocator, "Cannot read file \"{s}\": {s}", .{ r.prettyPath(fs.Path.init(input_path)), @errorName(err) }) catch unreachable;
             }
@@ -60,7 +62,7 @@ pub const PackageJSON = struct {
             debug.addNoteFmt("The file \"{s}\" exists", .{package_json_path}) catch unreachable;
         }
 
-        const key_path = fs.Path.init(r.allocator.dupe(u8, package_json_path) catch unreachable);
+        const key_path = fs.Path.init(package_json_path);
 
         var json_source = logger.Source.initPathString(key_path.text, entry.contents);
         json_source.path.pretty = r.prettyPath(json_source.path);
diff --git a/src/resolver/resolver.zig b/src/resolver/resolver.zig
index b28a28e4b..929fdb27c 100644
--- a/src/resolver/resolver.zig
+++ b/src/resolver/resolver.zig
@@ -45,7 +45,19 @@ pub const DirInfo = struct {
     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 {
+    pub fn getFileDescriptor(dirinfo: *const DirInfo) StoredFileDescriptorType {
+        if (!FeatureFlags.store_file_descriptors) {
+            return 0;
+        }
+
+        if (dirinfo.getEntries()) |entries| {
+            return entries.fd;
+        } else {
+            return 0;
+        }
+    }
+
+    pub fn getEntries(dirinfo: *const DirInfo) ?*Fs.FileSystem.DirEntry {
         var entries_ptr = Fs.FileSystem.instance.fs.entries.atIndex(dirinfo.entries) orelse return null;
         switch (entries_ptr.*) {
             .entries => |entr| {
@@ -57,10 +69,10 @@ pub const DirInfo = struct {
         }
     }
 
-    pub fn getParent(i: *DirInfo) ?*DirInfo {
+    pub fn getParent(i: *const DirInfo) ?*DirInfo {
         return HashMap.instance.atIndex(i.parent);
     }
-    pub fn getEnclosingBrowserScope(i: *DirInfo) ?*DirInfo {
+    pub fn getEnclosingBrowserScope(i: *const DirInfo) ?*DirInfo {
         return HashMap.instance.atIndex(i.enclosing_browser_scope);
     }
 
@@ -250,6 +262,9 @@ pub const Resolver = struct {
 
         debug_meta: ?DebugMeta = null,
 
+        dirname_fd: StoredFileDescriptorType = 0,
+        file_fd: StoredFileDescriptorType = 0,
+
         // Most NPM modules are CommonJS
         // If unspecified, assume CommonJS.
         // If internal app code, assume ESM. Since this is designed for ESM.`
@@ -428,6 +443,7 @@ pub const Resolver = struct {
                             return Result{
                                 .path_pair = res.path_pair,
                                 .diff_case = res.diff_case,
+                                .dirname_fd = dir_info.getFileDescriptor(),
                                 .is_from_node_modules = res.is_node_module,
                             };
                         }
@@ -452,7 +468,12 @@ pub const Resolver = struct {
 
             // Run node's resolution rules (e.g. adding ".js")
             if (r.loadAsFileOrDirectory(import_path, kind)) |entry| {
-                return Result{ .path_pair = entry.path_pair, .diff_case = entry.diff_case, .is_from_node_modules = entry.is_node_module };
+                return Result{
+                    .dirname_fd = entry.dirname_fd,
+                    .path_pair = entry.path_pair,
+                    .diff_case = entry.diff_case,
+                    .is_from_node_modules = entry.is_node_module,
+                };
             }
 
             return null;
@@ -508,6 +529,7 @@ pub const Resolver = struct {
                                     .diff_case = _result.diff_case,
                                     .is_from_node_modules = _result.is_node_module,
                                     .module_type = pkg.module_type,
+                                    .dirname_fd = _result.dirname_fd,
                                 };
                                 check_relative = false;
                                 check_package = false;
@@ -524,6 +546,7 @@ pub const Resolver = struct {
                         .path_pair = res.path_pair,
                         .diff_case = res.diff_case,
                         .is_from_node_modules = res.is_node_module,
+                        .dirname_fd = res.dirname_fd,
                     };
                 } else if (!check_package) {
                     return null;
@@ -569,6 +592,7 @@ pub const Resolver = struct {
                                 }
                                 return Result{
                                     .path_pair = pair,
+                                    .dirname_fd = node_module.dirname_fd,
                                     .diff_case = node_module.diff_case,
                                     .is_from_node_modules = true,
                                 };
@@ -591,6 +615,7 @@ pub const Resolver = struct {
                     .path_pair = res.path_pair,
                     .diff_case = res.diff_case,
                     .is_from_node_modules = res.is_node_module,
+                    .dirname_fd = res.dirname_fd,
                 };
             } else {
                 // Note: node's "self references" are not currently supported
@@ -611,9 +636,11 @@ pub const Resolver = struct {
                     path.is_disabled = true;
                 } else if (r.resolveWithoutRemapping(dir_info, remapped, kind)) |remapped_result| {
                     result.is_from_node_modules = remapped_result.is_node_module;
+
                     switch (iter.index) {
                         0 => {
                             result.path_pair.primary = remapped_result.path_pair.primary;
+                            result.dirname_fd = remapped_result.dirname_fd;
                         },
                         else => {
                             result.path_pair.secondary = remapped_result.path_pair.primary;
@@ -728,7 +755,7 @@ pub const Resolver = struct {
             //     //     if (!strings.eql(std.fs.path.basename(current), "node_modules")) {
             //     //         var paths1 = [_]string{ current, "node_modules", extends };
             //     //         var join1 = r.fs.absAlloc(ctx.r.allocator, &paths1) catch unreachable;
-            //     //         const res = ctx.r.parseTSConfig(join1, ctx.visited) catch |err| {
+            //     //         const res = ctx.r.parseTSConfig(join1, ctx.1) catch |err| {
             //     //             if (err == error.ENOENT) {
             //     //                 continue;
             //     //             } else if (err == error.ParseErrorImportCycle) {} else if (err != error.ParseErrorAlreadyLogged) {}
@@ -743,12 +770,16 @@ pub const Resolver = struct {
     };
 
     threadlocal var tsconfig_base_url_buf: [std.fs.MAX_PATH_BYTES]u8 = undefined;
-    pub fn parseTSConfig(r: *Resolver, file: string, visited: *StringBoolMap) !?*TSConfigJSON {
-        if (visited.contains(file)) {
-            return error.ParseErrorImportCycle;
-        }
-        visited.put(file, true) catch unreachable;
-        const entry = try r.caches.fs.readFile(r.fs, file);
+    pub fn parseTSConfig(
+        r: *Resolver,
+        file: string,
+        dirname_fd: StoredFileDescriptorType,
+    ) !?*TSConfigJSON {
+        const entry = try r.caches.fs.readFile(
+            r.fs,
+            file,
+            dirname_fd,
+        );
         const key_path = Path.init(file);
 
         const source = logger.Source.initPathString(key_path.text, entry.contents);
@@ -778,8 +809,8 @@ pub const Resolver = struct {
         return path.text;
     }
 
-    pub fn parsePackageJSON(r: *Resolver, file: string) !?*PackageJSON {
-        const pkg = PackageJSON.parse(r, file) orelse return null;
+    pub fn parsePackageJSON(r: *Resolver, file: string, dirname_fd: StoredFileDescriptorType) !?*PackageJSON {
+        const pkg = PackageJSON.parse(r, file, dirname_fd) orelse return null;
         var _pkg = try r.allocator.create(PackageJSON);
         _pkg.* = pkg;
         return _pkg;
@@ -846,7 +877,7 @@ pub const Resolver = struct {
         defer {
 
             // Anything
-            if (open_dir_count > 0) {
+            if (open_dir_count > 0 and r.fs.fs.needToCloseFiles()) {
                 var open_dirs: []std.fs.Dir = _open_dirs[0..open_dir_count];
                 for (open_dirs) |*open_dir| {
                     open_dir.close();
@@ -928,7 +959,7 @@ pub const Resolver = struct {
 
                 return null;
             };
-
+            Fs.FileSystem.setMaxFd(open_dir.fd);
             // 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;
@@ -959,6 +990,12 @@ pub const Resolver = struct {
                 dir_entries_option = try rfs.entries.put(&cached_dir_entry_result, .{
                     .entries = Fs.FileSystem.DirEntry.init(dir_path, r.fs.allocator),
                 });
+
+                if (FeatureFlags.store_file_descriptors) {
+                    Fs.FileSystem.setMaxFd(open_dir.fd);
+                    dir_entries_option.entries.fd = open_dir.fd;
+                }
+
                 has_dir_entry_result = true;
             }
 
@@ -974,6 +1011,7 @@ pub const Resolver = struct {
                 cached_dir_entry_result.index,
                 r.dir_cache.atIndex(top_parent.index),
                 top_parent.index,
+                open_dir.fd,
             );
 
             var dir_info_ptr = try r.dir_cache.put(&queue_top.result, dir_info);
@@ -998,6 +1036,8 @@ pub const Resolver = struct {
 
     pub const MatchResult = struct {
         path_pair: PathPair,
+        dirname_fd: StoredFileDescriptorType = 0,
+        file_fd: StoredFileDescriptorType = 0,
         is_node_module: bool = false,
         diff_case: ?Fs.FileSystem.Entry.Lookup.DifferentCase = null,
     };
@@ -1137,6 +1177,7 @@ pub const Resolver = struct {
     pub const LoadResult = struct {
         path: string,
         diff_case: ?Fs.FileSystem.Entry.Lookup.DifferentCase,
+        dirname_fd: StoredFileDescriptorType = 0,
     };
 
     pub fn checkBrowserMap(r: *Resolver, pkg: *PackageJSON, input_path: string) ?string {
@@ -1259,7 +1300,11 @@ pub const Resolver = struct {
                             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,
+                            .dirname_fd = dir_info.getFileDescriptor(),
+                        };
                     }
                 }
             }
@@ -1296,7 +1341,7 @@ pub const Resolver = struct {
 
                     // Is this a file
                     if (r.loadAsFile(remapped_abs, extension_order)) |file_result| {
-                        return MatchResult{ .path_pair = .{ .primary = Path.init(file_result.path) }, .diff_case = file_result.diff_case };
+                        return MatchResult{ .dirname_fd = file_result.dirname_fd, .path_pair = .{ .primary = Path.init(file_result.path) }, .diff_case = file_result.diff_case };
                     }
 
                     // Is it a directory with an index?
@@ -1319,7 +1364,11 @@ pub const Resolver = struct {
 
         // Is this a file?
         if (r.loadAsFile(path, extension_order)) |file| {
-            return MatchResult{ .path_pair = .{ .primary = Path.init(file.path) }, .diff_case = file.diff_case };
+            return MatchResult{
+                .path_pair = .{ .primary = Path.init(file.path) },
+                .diff_case = file.diff_case,
+                .dirname_fd = file.dirname_fd,
+            };
         }
 
         // Is this a directory?
@@ -1396,6 +1445,7 @@ pub const Resolver = struct {
                                         .secondary = _result.path_pair.primary,
                                     },
                                     .diff_case = auto_main_result.diff_case,
+                                    .dirname_fd = auto_main_result.dirname_fd,
                                 };
                             } else {
                                 if (r.debug_logs) |*debug| {
@@ -1453,7 +1503,7 @@ pub const Resolver = struct {
             return null;
         }
 
-        var entries = dir_entry.entries;
+        const entries = dir_entry.entries;
 
         const base = std.fs.path.basename(path);
 
@@ -1470,7 +1520,11 @@ pub const Resolver = struct {
                 const abs_path_parts = [_]string{ query.entry.dir, query.entry.base };
                 const abs_path = r.fs.filename_store.append(r.fs.joinBuf(&abs_path_parts, &TemporaryBuffer.ExtensionPathBuf)) catch unreachable;
 
-                return LoadResult{ .path = abs_path, .diff_case = query.diff_case };
+                return LoadResult{
+                    .path = abs_path,
+                    .diff_case = query.diff_case,
+                    .dirname_fd = entries.fd,
+                };
             }
         }
 
@@ -1496,6 +1550,7 @@ pub const Resolver = struct {
                     return LoadResult{
                         .path = r.fs.filename_store.append(buffer) catch unreachable,
                         .diff_case = query.diff_case,
+                        .dirname_fd = entries.fd,
                     };
                 }
             }
@@ -1537,6 +1592,7 @@ pub const Resolver = struct {
                             return LoadResult{
                                 .path = r.fs.filename_store.append(buffer) catch unreachable,
                                 .diff_case = query.diff_case,
+                                .dirname_fd = entries.fd,
                             };
                         }
                     }
@@ -1562,6 +1618,7 @@ pub const Resolver = struct {
         dir_entry_index: allocators.IndexType,
         parent: ?*DirInfo,
         parent_index: allocators.IndexType,
+        fd: FileDescriptorType,
     ) anyerror!DirInfo {
         var result = _result;
 
@@ -1621,7 +1678,7 @@ pub const Resolver = struct {
         if (entries.get("package.json")) |lookup| {
             const entry = lookup.entry;
             if (entry.kind(rfs) == .file) {
-                info.package_json = r.parsePackageJSON(path) catch null;
+                info.package_json = r.parsePackageJSON(path, if (FeatureFlags.store_file_descriptors) fd else 0) catch null;
 
                 if (info.package_json) |pkg| {
                     if (pkg.browser_map.count() > 0) {
@@ -1663,9 +1720,10 @@ pub const Resolver = struct {
             }
 
             if (tsconfig_path) |tsconfigpath| {
-                var visited = std.StringHashMap(bool).init(r.allocator);
-                defer visited.deinit();
-                info.tsconfig_json = r.parseTSConfig(tsconfigpath, &visited) catch |err| brk: {
+                info.tsconfig_json = r.parseTSConfig(
+                    tsconfigpath,
+                    if (FeatureFlags.store_file_descriptors) fd else 0,
+                ) catch |err| brk: {
                     const pretty = r.prettyPath(Path.init(tsconfigpath));
 
                     if (err == error.ENOENT) {
diff --git a/src/test/fixtures/await.ts b/src/test/fixtures/await.ts
index 802b3b3f0..f927d2c38 100644
--- a/src/test/fixtures/await.ts
+++ b/src/test/fixtures/await.ts
@@ -1 +1,3 @@
-const init: (VariableDeclaration | AnyExpression) = true;
+function hey() {
+  const foo = process.env.node_eNV;
+}