reducing dependencies

Author: jakubDoka

Cargo.toml

@@ -17,7 +17,6 @@ repository = "https://github.com/bytecodealliance/regalloc2"
 log = { version = "0.4.8", default-features = false }
 smallvec = { version = "1.6.1", features = ["union"] }
 rustc-hash = { version = "2.0.0", default-features = false }
-slice-group-by = { version = "0.3.0", default-features = false }
 hashbrown = { version = "0.14", default-features = false, features = [] }
 
 # Optional serde support, enabled by feature below.
@@ -28,8 +27,8 @@ serde = { version = "1.0.136", features = [
 
 # The below are only needed for fuzzing.
 libfuzzer-sys = { version = "0.4.2", optional = true }
-bumpalo = { version = "3.16.0", features = ["allocator-api2"] }
-allocator-api2 = { version = "0.2.18", default-features = false, features = ["alloc"] }
+bumpalo = { version = "3.16.0", features = [] }
+allocator-api2 = { version = "0.2.18", default-features = false, features = ["alloc"], optional = true }
 
 # When testing regalloc2 by itself, enable debug assertions and overflow checks
 [profile.release]
@@ -38,7 +37,7 @@ debug-assertions = true
 overflow-checks = true
 
 [features]
-default = ["std"]
+default = ["std", "allocator-api2"]
 
 # Enables std-specific features such as the Error trait for RegAllocError.
 std = []
@@ -54,3 +53,6 @@ fuzzing = ["libfuzzer-sys", "checker", "trace-log"]
 
 # Enables serde for exposed types.
 enable-serde = ["serde"]
+
+allocator-api2 = ["dep:allocator-api2", "bumpalo/allocator-api2"]
+nightly = ["bumpalo/allocator_api"]

src/ion/data_structures.rs

@@ -26,12 +26,21 @@ use alloc::collections::VecDeque;
 use alloc::rc::Rc;
 use alloc::string::String;
 use alloc::vec::Vec;
+use allocator_api2::alloc::Allocator;
 use core::cmp::Ordering;
 use core::convert::identity;
 use core::fmt::Debug;
 use core::ops::{Deref, DerefMut};
 use smallvec::SmallVec;
 
+#[cfg(not(feature = "allocator-api2"))]
+use core as allocator_api2;
+
+#[cfg(not(feature = "allocator-api2"))]
+use alloc::vec as bump_vec;
+#[cfg(feature = "allocator-api2")]
+use allocator_api2::vec as bump_vec;
+
 #[derive(Debug, Clone, Default)]
 pub struct Bump(Rc<bumpalo::Bump>);
 
@@ -42,7 +51,7 @@ impl Bump {
 }
 
 // simply delegating beause `Rc<bumpalo::Bump>` does not implement `Allocator`
-unsafe impl allocator_api2::alloc::Allocator for Bump {
+unsafe impl Allocator for Bump {
     fn allocate(
         &self,
         layout: core::alloc::Layout,
@@ -85,7 +94,8 @@ unsafe impl allocator_api2::alloc::Allocator for Bump {
         old_layout: core::alloc::Layout,
         new_layout: core::alloc::Layout,
     ) -> Result<core::ptr::NonNull<[u8]>, allocator_api2::alloc::AllocError> {
-        self.0.deref().shrink(ptr, old_layout, new_layout)
+        let f = self.0.deref().shrink(ptr, old_layout, new_layout);
+        f
     }
 }
 
@@ -230,8 +240,8 @@ pub struct LiveRangeListEntry {
     pub index: LiveRangeIndex,
 }
 
-pub type LiveRangeList = allocator_api2::vec::Vec<LiveRangeListEntry, Bump>;
-pub type UseList = allocator_api2::vec::Vec<Use, Bump>;
+pub type LiveRangeList = bump_vec::Vec<LiveRangeListEntry, Bump>;
+pub type UseList = bump_vec::Vec<Use, Bump>;
 
 #[derive(Clone, Debug)]
 pub struct LiveRange {

src/ion/liveranges.rs

@@ -24,7 +24,6 @@ use crate::{
     Allocation, Block, Function, Inst, InstPosition, Operand, OperandConstraint, OperandKind,
     OperandPos, PReg, ProgPoint, RegAllocError, VReg, VecExt,
 };
-use slice_group_by::GroupByMut;
 use smallvec::{smallvec, SmallVec};
 
 /// A spill weight computed for a certain Use.
@@ -781,7 +780,7 @@ impl<'a, F: Function> Env<'a, F> {
                 // Find groups of uses that occur in at the same program point.
                 for uses in self.ctx.ranges[range]
                     .uses
-                    .linear_group_by_key_mut(|u| u.pos)
+                    .chunk_by_mut(|a, b| a.pos == b.pos)
                 {
                     if uses.len() < 2 {
                         continue;

src/lib.rs

@@ -12,8 +12,12 @@
 
 #![allow(dead_code)]
 #![allow(clippy::all)]
+#![cfg_attr(not(feature = "allocator-api2"), feature(allocator_api))]
 #![no_std]
 
+#[cfg(not(any(feature = "allocator-api2", feature = "nightly")))]
+compile_error!("feature `nightly` is required if `allocator-api2` is disabled");
+
 #[cfg(feature = "std")]
 extern crate std;