Partial support for no_std in cranelift_codegen (#12222)

the-ssd · alexcrichton · web-flow · commit 76911c2957bb · 2026-01-07T16:41:32.000Z
* Move most things from std to core and alloc

* Port assembler_x64 to no_std

* before adding prelude to each file

* Most of the files now work with no_std

* update isle to use alloc and core

* some instances shouldn't have been renamed, fixes cargo test

* add cranelift-assembler-x64 (no_std) to CI

* fix codegen_meta, missed one spot with std::slice

* automatically remove prelude with cargo fix

* update isle changes

* update assembler changes

* update assembler changes

* use latest codegen changes + fix FxHash problem

* add imports

* fix floating issues with libm

* remove unused import

* temporarily remove OnceLock

* add no_std arm support and add it into CI

* Move most things from std to core and alloc

* Port assembler_x64 to no_std

* before adding prelude to each file

* Most of the files now work with no_std

* update isle to use alloc and core

* some instances shouldn't have been renamed, fixes cargo test

* add cranelift-assembler-x64 (no_std) to CI

* automatically remove prelude with cargo fix

* update isle changes

* update assembler changes

* update assembler changes

* use latest codegen changes + fix FxHash problem

* add imports

* fix floating issues with libm

* remove unused import

* temporarily remove OnceLock

* add no_std arm support and add it into CI

* Move most things from std to core and alloc

* Port assembler_x64 to no_std

* before adding prelude to each file

* Most of the files now work with no_std

* update isle to use alloc and core

* add cranelift-assembler-x64 (no_std) to CI

* automatically remove prelude with cargo fix

* update isle changes

* update assembler changes

* use latest codegen changes + fix FxHash problem

* add imports

* fix floating issues with libm

* temporarily remove OnceLock

* add no_std arm support and add it into CI

* revert Cargo.toml formating

* remove prelude and fix cargo.toml

* cargo fmt

* remove empty lines

* bad renames

* macro_use only on no_std

* revert OnceLock change

* only use stable libm features

* update regalloc2

* update comment

* use continue instead

* Update vets

---------

Co-authored-by: Alex Crichton &lt;alex@alexcrichton.com&gt;
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -304,7 +304,7 @@ cranelift-jit = { path = "cranelift/jit", version = "0.129.0" }
 cranelift-fuzzgen = { path = "cranelift/fuzzgen" }
 cranelift-bforest = { path = "cranelift/bforest", version = "0.129.0" }
 cranelift-bitset = { path = "cranelift/bitset", version = "0.129.0" }
-cranelift-control = { path = "cranelift/control", version = "0.129.0" }
+cranelift-control = { path = "cranelift/control", version = "0.129.0", default-features = false }
 cranelift-srcgen = { path = "cranelift/srcgen", version = "0.129.0" }
 cranelift = { path = "cranelift/umbrella", version = "0.129.0" }
 
@@ -322,7 +322,7 @@ component-async-tests = { path = "crates/misc/component-async-tests" }
 
 # Bytecode Alliance maintained dependencies:
 # ---------------------------
-regalloc2 = "0.13.3"
+regalloc2 = "0.13.4"
 wasip1 = { version = "1.0.0", default-features = false }
 
 # cap-std family:
@@ -414,7 +414,7 @@ tracing-subscriber = { version = "0.3.20", default-features = false, features =
 url = "2.5.7"
 postcard = { version = "1.1.3", default-features = false, features = ['alloc'] }
 criterion = { version = "0.7.0", default-features = false, features = ["html_reports", "rayon"] }
-rustc-hash = "2.1.1"
+rustc-hash = { version = "2.1.1", default-features = false }
 libtest-mimic = "0.8.1"
 semver = { version = "1.0.27", default-features = false }
 ittapi = "0.4.0"
diff --git a/cranelift/codegen/Cargo.toml b/cranelift/codegen/Cargo.toml
@@ -30,20 +30,21 @@ cranelift-entity = { workspace = true }
 cranelift-bforest = { workspace = true }
 cranelift-bitset = { workspace = true }
 cranelift-control = { workspace = true }
-hashbrown = { workspace = true }
+hashbrown = { workspace = true, features = ["default-hasher"] }
 target-lexicon = { workspace = true }
 log = { workspace = true }
 serde = { workspace = true, optional = true }
 serde_derive = { workspace = true, optional = true }
 pulley-interpreter = { workspace = true, optional = true }
 postcard = { workspace = true, optional = true }
-gimli = { workspace = true, features = ["write", "std"], optional = true }
+gimli = { workspace = true, features = ["write"], optional = true }
 smallvec = { workspace = true }
 regalloc2 = { workspace = true, features = ["checker"] }
 souper-ir = { version = "2.1.0", optional = true }
 sha2 = { version = "0.10.2", optional = true }
 rustc-hash = { workspace = true }
 wasmtime-math = { workspace = true }
+libm = { workspace = true }
 # It is a goal of the cranelift-codegen crate to have minimal external dependencies.
 # Please don't add any unless they are essential to the task of creating binary
 # machine code. Integration tests that need external dependencies can be
@@ -65,7 +66,7 @@ default = ["std", "unwind", "host-arch", "timing"]
 # The "std" feature enables use of libstd. The "core" feature enables use
 # of some minimal std-like replacement libraries. At least one of these two
 # features need to be enabled.
-std = ["serde?/std"]
+std = ["serde?/std", "rustc-hash/std", "gimli/std", "cranelift-control/fuzz"]
 
 # The "core" feature used to enable a hashmap workaround, but is now
 # deprecated (we (i) always use hashbrown, and (ii) don't support a
diff --git a/cranelift/codegen/src/alias_analysis.rs b/cranelift/codegen/src/alias_analysis.rs
@@ -61,6 +61,7 @@
 //! must be correct likely reduce the potential benefit, we don't yet
 //! do this.
 
+use crate::{FxHashMap, FxHashSet};
 use crate::{
     cursor::{Cursor, FuncCursor},
     dominator_tree::DominatorTree,
@@ -71,7 +72,6 @@ use crate::{
     trace,
 };
 use cranelift_entity::{EntityRef, packed_option::PackedOption};
-use rustc_hash::{FxHashMap, FxHashSet};
 
 /// For a given program point, the vector of last-store instruction
 /// indices for each disjoint category of abstract state.
diff --git a/cranelift/codegen/src/egraph/elaborate.rs b/cranelift/codegen/src/egraph/elaborate.rs
@@ -11,10 +11,10 @@ use crate::ir::{Block, Function, Inst, Value, ValueDef};
 use crate::loop_analysis::{Loop, LoopAnalysis};
 use crate::scoped_hash_map::ScopedHashMap;
 use crate::trace;
+use crate::{FxHashMap, FxHashSet};
 use alloc::vec::Vec;
 use cranelift_control::ControlPlane;
 use cranelift_entity::{EntitySet, SecondaryMap, packed_option::ReservedValue};
-use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::{SmallVec, smallvec};
 
 pub(crate) struct Elaborator<'a> {
diff --git a/cranelift/codegen/src/egraph/mod.rs b/cranelift/codegen/src/egraph/mod.rs
@@ -1,5 +1,6 @@
 //! Support for egraphs represented in the DataFlowGraph.
 
+use crate::FxHashSet;
 use crate::alias_analysis::{AliasAnalysis, LastStores};
 use crate::ctxhash::{CtxEq, CtxHash, NullCtx};
 use crate::cursor::{Cursor, CursorPosition, FuncCursor};
@@ -24,7 +25,6 @@ use core::hash::Hasher;
 use cranelift_control::ControlPlane;
 use cranelift_entity::SecondaryMap;
 use cranelift_entity::packed_option::ReservedValue;
-use rustc_hash::FxHashSet;
 use smallvec::SmallVec;
 
 mod cost;
diff --git a/cranelift/codegen/src/ir/immediates.rs b/cranelift/codegen/src/ir/immediates.rs
@@ -10,6 +10,7 @@ use core::fmt::{self, Display, Formatter};
 use core::ops::{Add, BitAnd, BitOr, BitXor, Div, Mul, Neg, Not, Sub};
 use core::str::FromStr;
 use core::{i32, u32};
+use libm::Libm;
 #[cfg(feature = "enable-serde")]
 use serde_derive::{Deserialize, Serialize};
 
@@ -682,27 +683,29 @@ macro_rules! ieee_float {
             $(
                 /// Returns the square root of `self`.
                 pub fn sqrt(self) -> Self {
-                    Self::with_float(self.$as_float().sqrt())
+                    Self::with_float(Libm::<$float_ty>::sqrt(self.$as_float()))
                 }
 
                 /// Returns the smallest integer greater than or equal to `self`.
                 pub fn ceil(self) -> Self {
-                    Self::with_float(self.$as_float().ceil())
+                    Self::with_float(Libm::<$float_ty>::ceil(self.$as_float()))
                 }
 
                 /// Returns the largest integer less than or equal to `self`.
                 pub fn floor(self) -> Self {
-                    Self::with_float(self.$as_float().floor())
+                    Self::with_float(Libm::<$float_ty>::floor(self.$as_float()))
                 }
 
                 /// Returns the integer part of `self`. This means that non-integer numbers are always truncated towards zero.
                 pub fn trunc(self) -> Self {
-                    Self::with_float(self.$as_float().trunc())
+                    Self::with_float(Libm::<$float_ty>::trunc(self.$as_float()))
                 }
 
                 /// Returns the nearest integer to `self`. Rounds half-way cases to the number
                 /// with an even least significant digit.
                 pub fn round_ties_even(self) -> Self {
+                    // TODO: when libm v0.2.16 is published line below can be used instead
+                    // Self::with_float(Libm::<$float_ty>::roundeven(self.$as_float()))
                     Self::with_float(self.$as_float().round_ties_even())
                 }
             )?
diff --git a/cranelift/codegen/src/isa/unwind.rs b/cranelift/codegen/src/isa/unwind.rs
@@ -14,6 +14,7 @@ pub mod winx64;
 #[cfg(feature = "unwind")]
 pub mod winarm64;
 
+#[cfg(feature = "unwind")]
 /// CFA-based unwind information used on SystemV.
 pub type CfaUnwindInfo = systemv::UnwindInfo;
 
diff --git a/cranelift/codegen/src/isa/x64/mod.rs b/cranelift/codegen/src/isa/x64/mod.rs
@@ -28,6 +28,7 @@ mod lower;
 mod pcc;
 pub mod settings;
 
+#[cfg(feature = "unwind")]
 pub use inst::unwind::systemv::create_cie;
 
 /// An X64 backend.
@@ -217,6 +218,7 @@ pub fn emit_unwind_info(
 ) -> CodegenResult<Option<crate::isa::unwind::UnwindInfo>> {
     use crate::isa::unwind::{UnwindInfo, UnwindInfoKind};
     Ok(match kind {
+        #[cfg(feature = "unwind")]
         UnwindInfoKind::SystemV => {
             let mapper = self::inst::unwind::systemv::RegisterMapper;
             Some(UnwindInfo::SystemV(
@@ -227,6 +229,7 @@ pub fn emit_unwind_info(
                 )?,
             ))
         }
+        #[cfg(feature = "unwind")]
         UnwindInfoKind::Windows => Some(UnwindInfo::WindowsX64(
             crate::isa::unwind::winx64::create_unwind_info_from_insts::<
                 self::inst::unwind::winx64::RegisterMapper,
diff --git a/cranelift/codegen/src/lib.rs b/cranelift/codegen/src/lib.rs
@@ -14,6 +14,7 @@
     allow(dead_code, reason = "see comment above")
 )]
 
+#[cfg_attr(not(feature = "std"), macro_use)]
 extern crate alloc;
 
 #[cfg(feature = "std")]
@@ -23,7 +24,12 @@ extern crate std;
 #[cfg(not(feature = "std"))]
 use hashbrown::{HashMap, HashSet, hash_map};
 #[cfg(feature = "std")]
-use std::collections::{HashMap, hash_map};
+use std::collections::{HashMap, HashSet, hash_map};
+
+/// Type alias for a hash map that uses the Fx hashing algorithm.
+pub type FxHashMap<K, V> = HashMap<K, V, rustc_hash::FxBuildHasher>;
+/// Type alias for a hash set that uses the Fx hashing algorithm.
+pub type FxHashSet<V> = HashSet<V, rustc_hash::FxBuildHasher>;
 
 pub use crate::context::Context;
 pub use crate::value_label::{LabelValueLoc, ValueLabelsRanges, ValueLocRange};
diff --git a/cranelift/codegen/src/machinst/abi.rs b/cranelift/codegen/src/machinst/abi.rs
@@ -99,6 +99,7 @@
 //! ABI. See each platform's `abi.rs` implementation for details.
 
 use crate::CodegenError;
+use crate::FxHashMap;
 use crate::HashMap;
 use crate::entity::SecondaryMap;
 use crate::ir::{ArgumentExtension, ArgumentPurpose, ExceptionTag, Signature};
@@ -110,7 +111,6 @@ use crate::{machinst::*, trace};
 use alloc::boxed::Box;
 use core::marker::PhantomData;
 use regalloc2::{MachineEnv, PReg, PRegSet};
-use rustc_hash::FxHashMap;
 use smallvec::smallvec;
 
 /// A small vector of instructions (with some reasonable size); appropriate for
diff --git a/cranelift/codegen/src/machinst/blockorder.rs b/cranelift/codegen/src/machinst/blockorder.rs
@@ -64,8 +64,8 @@ use crate::dominator_tree::DominatorTree;
 use crate::entity::SecondaryMap;
 use crate::inst_predicates::visit_block_succs;
 use crate::ir::{Block, Function, Inst, Opcode};
+use crate::{FxHashMap, FxHashSet};
 use crate::{machinst::*, trace};
-use rustc_hash::{FxHashMap, FxHashSet};
 
 /// Mapping from CLIF BBs to VCode BBs.
 #[derive(Debug)]
diff --git a/cranelift/codegen/src/machinst/compile.rs b/cranelift/codegen/src/machinst/compile.rs
@@ -82,7 +82,7 @@ pub fn compile<B: LowerBackend + TargetIsa>(
     // Run the regalloc checker, if requested.
     if b.flags().regalloc_checker() {
         let _tt = timing::regalloc_checker();
-        let mut checker = regalloc2::checker::Checker::new(&vcode, vcode.abi.machine_env());
+        let mut checker = regalloc2::checker::Checker::new(&vcode, &vcode.abi.machine_env());
         checker.prepare(&regalloc_result);
         checker
             .run()
diff --git a/cranelift/codegen/src/machinst/lower.rs b/cranelift/codegen/src/machinst/lower.rs
@@ -22,10 +22,10 @@ use crate::machinst::{
 };
 use crate::settings::Flags;
 use crate::{CodegenError, CodegenResult, trace};
+use crate::{FxHashMap, FxHashSet};
 use alloc::vec::Vec;
 use core::fmt::Debug;
 use cranelift_control::ControlPlane;
-use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::{SmallVec, smallvec};
 
 use super::{VCodeBuildDirection, VRegAllocator};
diff --git a/cranelift/codegen/src/machinst/vcode.rs b/cranelift/codegen/src/machinst/vcode.rs
@@ -18,6 +18,7 @@
 //! backend pipeline.
 
 use crate::CodegenError;
+use crate::FxHashMap;
 use crate::ir::pcc::*;
 use crate::ir::{self, Constant, ConstantData, ValueLabel, types};
 use crate::ranges::Ranges;
@@ -29,7 +30,6 @@ use regalloc2::{
     Edit, Function as RegallocFunction, InstOrEdit, InstPosition, InstRange, Operand,
     OperandConstraint, OperandKind, PRegSet, ProgPoint, RegClass,
 };
-use rustc_hash::FxHashMap;
 
 use crate::HashMap;
 use crate::hash_map::Entry;
@@ -1274,15 +1274,21 @@ impl<I: VCodeInst> VCode<I> {
             let loc = if let Some(preg) = alloc.as_reg() {
                 LabelValueLoc::Reg(Reg::from(preg))
             } else {
-                let slot = alloc.as_stack().unwrap();
-                let slot_offset = self.abi.get_spillslot_offset(slot);
-                let slot_base_to_caller_sp_offset = self.abi.slot_base_to_caller_sp_offset();
-                let caller_sp_to_cfa_offset =
-                    crate::isa::unwind::systemv::caller_sp_to_cfa_offset();
-                // NOTE: this is a negative offset because it's relative to the caller's SP
-                let cfa_to_sp_offset =
-                    -((slot_base_to_caller_sp_offset + caller_sp_to_cfa_offset) as i64);
-                LabelValueLoc::CFAOffset(cfa_to_sp_offset + slot_offset)
+                #[cfg(not(feature = "unwind"))]
+                continue;
+
+                #[cfg(feature = "unwind")]
+                {
+                    let slot = alloc.as_stack().unwrap();
+                    let slot_offset = self.abi.get_spillslot_offset(slot);
+                    let slot_base_to_caller_sp_offset = self.abi.slot_base_to_caller_sp_offset();
+                    let caller_sp_to_cfa_offset =
+                        crate::isa::unwind::systemv::caller_sp_to_cfa_offset();
+                    // NOTE: this is a negative offset because it's relative to the caller's SP
+                    let cfa_to_sp_offset =
+                        -((slot_base_to_caller_sp_offset + caller_sp_to_cfa_offset) as i64);
+                    LabelValueLoc::CFAOffset(cfa_to_sp_offset + slot_offset)
+                }
             };
 
             // Coalesce adjacent ranges that for the same location
diff --git a/cranelift/codegen/src/remove_constant_phis.rs b/cranelift/codegen/src/remove_constant_phis.rs
@@ -5,9 +5,9 @@ use crate::ir;
 use crate::ir::Function;
 use crate::ir::{Block, BlockArg, BlockCall, Inst, Value};
 use crate::timing;
+use crate::{FxHashMap, FxHashSet};
 use bumpalo::Bump;
 use cranelift_entity::SecondaryMap;
-use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::SmallVec;
 
 // A note on notation.  For the sake of clarity, this file uses the phrase
diff --git a/supply-chain/imports.lock b/supply-chain/imports.lock
@@ -1327,8 +1327,8 @@ user-login = "dtolnay"
 user-name = "David Tolnay"
 
 [[publisher.regalloc2]]
-version = "0.13.3"
-when = "2025-11-13"
+version = "0.13.4"
+when = "2026-01-06"
 user-id = 3726
 user-login = "cfallin"
 user-name = "Chris Fallin"
