From decfb4d123651a0673db47542e18ca60d1c501ac Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Tue, 21 Feb 2023 08:37:10 +0000
Subject: Use a lock-free datastructure for `source_span`

---
 compiler/rustc_data_structures/Cargo.toml      |  1 +
 compiler/rustc_data_structures/src/sync.rs     |  4 +++
 compiler/rustc_data_structures/src/sync/vec.rs | 41 ++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)
 create mode 100644 compiler/rustc_data_structures/src/sync/vec.rs

(limited to 'compiler/rustc_data_structures')

diff --git a/compiler/rustc_data_structures/Cargo.toml b/compiler/rustc_data_structures/Cargo.toml
index 0366fb0a148..a6601fbf43b 100644
--- a/compiler/rustc_data_structures/Cargo.toml
+++ b/compiler/rustc_data_structures/Cargo.toml
@@ -31,6 +31,7 @@ stacker = "0.1.15"
 tempfile = "3.2"
 thin-vec = "0.2.9"
 tracing = "0.1"
+elsa = "1.8"
 
 [dependencies.parking_lot]
 version = "0.11"
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index ad71dcdf9d9..31323c21df0 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -26,6 +26,10 @@ use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe};
 pub use std::sync::atomic::Ordering;
 pub use std::sync::atomic::Ordering::SeqCst;
 
+pub use vec::AppendOnlyVec;
+
+mod vec;
+
 cfg_if! {
     if #[cfg(not(parallel_compiler))] {
         pub auto trait Send {}
diff --git a/compiler/rustc_data_structures/src/sync/vec.rs b/compiler/rustc_data_structures/src/sync/vec.rs
new file mode 100644
index 00000000000..cbea4f05999
--- /dev/null
+++ b/compiler/rustc_data_structures/src/sync/vec.rs
@@ -0,0 +1,41 @@
+use std::marker::PhantomData;
+
+use rustc_index::vec::Idx;
+
+pub struct AppendOnlyVec<I: Idx, T: Copy> {
+    #[cfg(not(parallel_compiler))]
+    vec: elsa::vec::FrozenVec<T>,
+    #[cfg(parallel_compiler)]
+    vec: elsa::sync::LockFreeFrozenVec<T>,
+    _marker: PhantomData<fn(&I)>,
+}
+
+impl<I: Idx, T: Copy> AppendOnlyVec<I, T> {
+    pub fn new() -> Self {
+        Self {
+            #[cfg(not(parallel_compiler))]
+            vec: elsa::vec::FrozenVec::new(),
+            #[cfg(parallel_compiler)]
+            vec: elsa::sync::LockFreeFrozenVec::new(),
+            _marker: PhantomData,
+        }
+    }
+
+    pub fn push(&self, val: T) -> I {
+        #[cfg(not(parallel_compiler))]
+        let i = self.vec.len();
+        #[cfg(not(parallel_compiler))]
+        self.vec.push(val);
+        #[cfg(parallel_compiler)]
+        let i = self.vec.push(val);
+        I::new(i)
+    }
+
+    pub fn get(&self, i: I) -> Option<T> {
+        let i = i.index();
+        #[cfg(not(parallel_compiler))]
+        return self.vec.get_copy(i);
+        #[cfg(parallel_compiler)]
+        return self.vec.get(i);
+    }
+}
-- 
cgit 1.4.1-3-g733a5