From be3a635fe777d4aac653994749ad47e650e71c1e Mon Sep 17 00:00:00 2001
From: klensy <klensy@users.noreply.github.com>
Date: Sat, 2 Nov 2024 15:08:53 +0300
Subject: [PATCH 1/2] replace manual time convertions with std ones

---
 compiler/rustc_incremental/src/persist/fs.rs   | 18 ++++++------------
 .../rustc_query_system/src/dep_graph/graph.rs  |  2 +-
 2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/compiler/rustc_incremental/src/persist/fs.rs b/compiler/rustc_incremental/src/persist/fs.rs
index 8769c4173c886..f6c3e8ebbcbd9 100644
--- a/compiler/rustc_incremental/src/persist/fs.rs
+++ b/compiler/rustc_incremental/src/persist/fs.rs
@@ -585,23 +585,17 @@ fn extract_timestamp_from_session_dir(directory_name: &str) -> Result<SystemTime
 
 fn timestamp_to_string(timestamp: SystemTime) -> BaseNString {
     let duration = timestamp.duration_since(UNIX_EPOCH).unwrap();
-    let micros = duration.as_secs() * 1_000_000 + (duration.subsec_nanos() as u64) / 1000;
+    let micros: u64 = duration.as_micros().try_into().unwrap();
     micros.to_base_fixed_len(CASE_INSENSITIVE)
 }
 
 fn string_to_timestamp(s: &str) -> Result<SystemTime, &'static str> {
-    let micros_since_unix_epoch = u64::from_str_radix(s, INT_ENCODE_BASE as u32);
-
-    if micros_since_unix_epoch.is_err() {
-        return Err("timestamp not an int");
-    }
-
-    let micros_since_unix_epoch = micros_since_unix_epoch.unwrap();
+    let micros_since_unix_epoch = match u64::from_str_radix(s, INT_ENCODE_BASE as u32) {
+        Ok(micros) => micros,
+        Err(_) => return Err("timestamp not an int"),
+    };
 
-    let duration = Duration::new(
-        micros_since_unix_epoch / 1_000_000,
-        1000 * (micros_since_unix_epoch % 1_000_000) as u32,
-    );
+    let duration = Duration::from_micros(micros_since_unix_epoch);
     Ok(UNIX_EPOCH + duration)
 }
 
diff --git a/compiler/rustc_query_system/src/dep_graph/graph.rs b/compiler/rustc_query_system/src/dep_graph/graph.rs
index 5e30f17d6269a..e7ed828849953 100644
--- a/compiler/rustc_query_system/src/dep_graph/graph.rs
+++ b/compiler/rustc_query_system/src/dep_graph/graph.rs
@@ -1098,7 +1098,7 @@ impl<D: Deps> CurrentDepGraph<D> {
         use std::time::{SystemTime, UNIX_EPOCH};
 
         let duration = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
-        let nanos = duration.as_secs() * 1_000_000_000 + duration.subsec_nanos() as u64;
+        let nanos = duration.as_nanos();
         let mut stable_hasher = StableHasher::new();
         nanos.hash(&mut stable_hasher);
         let anon_id_seed = stable_hasher.finish();

From bc1d8e72e793c61c4c22867e0802835178b8a309 Mon Sep 17 00:00:00 2001
From: klensy <klensy@users.noreply.github.com>
Date: Sat, 2 Nov 2024 15:20:11 +0300
Subject: [PATCH 2/2] make time format parsing compiletime

---
 compiler/rustc_driver_impl/Cargo.toml | 2 +-
 compiler/rustc_driver_impl/src/lib.rs | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_driver_impl/Cargo.toml b/compiler/rustc_driver_impl/Cargo.toml
index ef577c0321899..74da0d11e4ba6 100644
--- a/compiler/rustc_driver_impl/Cargo.toml
+++ b/compiler/rustc_driver_impl/Cargo.toml
@@ -49,7 +49,7 @@ rustc_trait_selection = { path = "../rustc_trait_selection" }
 rustc_ty_utils = { path = "../rustc_ty_utils" }
 serde_json = "1.0.59"
 shlex = "1.0"
-time = { version = "0.3.36", default-features = false, features = ["alloc", "formatting", "parsing", "macros"] }
+time = { version = "0.3.36", default-features = false, features = ["alloc", "formatting", "macros"] }
 tracing = { version = "0.1.35" }
 # tidy-alphabetical-end
 
diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index 4362007d4bae3..d2c4335cf2b44 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -64,6 +64,7 @@ use rustc_span::source_map::FileLoader;
 use rustc_target::json::ToJson;
 use rustc_target::spec::{Target, TargetTuple};
 use time::OffsetDateTime;
+use time::macros::format_description;
 use tracing::trace;
 
 #[allow(unused_macros)]
@@ -1356,8 +1357,7 @@ fn ice_path_with_config(config: Option<&UnstableOptions>) -> &'static Option<Pat
         let file_now = now
             .format(
                 // Don't use a standard datetime format because Windows doesn't support `:` in paths
-                &time::format_description::parse("[year]-[month]-[day]T[hour]_[minute]_[second]")
-                    .unwrap(),
+                &format_description!("[year]-[month]-[day]T[hour]_[minute]_[second]"),
             )
             .unwrap_or_default();
         let pid = std::process::id();