Allow building without std (#1069)

Closes https://github.com/CraneStation/cranelift/issues/1067

cranelift/codegen/src/binemit/memorysink.rs

@@ -99,7 +99,7 @@ impl<'a> MemoryCodeSink<'a> {
         unsafe {
             #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
             write_unaligned(self.data.offset(self.offset) as *mut T, x);
-            self.offset += std::mem::size_of::<T>() as isize;
+            self.offset += core::mem::size_of::<T>() as isize;
         }
     }
 }

cranelift/codegen/src/binemit/stackmap.rs

@@ -4,7 +4,7 @@ use crate::isa::TargetIsa;
 use std::vec::Vec;
 
 type Num = u32;
-const NUM_BITS: usize = std::mem::size_of::<Num>() * 8;
+const NUM_BITS: usize = core::mem::size_of::<Num>() * 8;
 
 /// Wrapper class for longer bit vectors that cannot be represented by a single BitSet.
 #[derive(Clone, Debug)]
@@ -20,7 +20,7 @@ impl Stackmap {
         isa: &dyn TargetIsa,
     ) -> Self {
         let loc = &func.locations;
-        let mut live_ref_in_stack_slot = std::collections::HashSet::new();
+        let mut live_ref_in_stack_slot = crate::HashSet::new();
         // References can be in registers, and live registers values are pushed onto the stack before calls and traps.
         // TODO: Implement register maps. If a register containing a reference is spilled and reused after a safepoint,
         // it could contain a stale reference value if the garbage collector relocated the value.

cranelift/codegen/src/divconst_magic_numbers.rs

@@ -1078,8 +1078,6 @@ mod tests {
                 d -= 1;
             }
         }
-
         assert_eq!(n_tests_done, 50_148_000);
     }
-
 }

cranelift/codegen/src/ir/constant.rs

@@ -9,8 +9,9 @@
 //! - bucketing constants by size.
 
 use crate::ir::Constant;
+use crate::HashMap;
 use cranelift_entity::EntityRef;
-use std::collections::{BTreeMap, HashMap};
+use std::collections::BTreeMap;
 use std::vec::Vec;
 
 /// This type describes the actual constant data.

cranelift/codegen/src/ir/dfg.rs

@@ -13,12 +13,12 @@ use crate::ir::{
 use crate::isa::TargetIsa;
 use crate::packed_option::ReservedValue;
 use crate::write::write_operands;
+use crate::HashMap;
 use core::fmt;
 use core::iter;
 use core::mem;
 use core::ops::{Index, IndexMut};
 use core::u16;
-use std::collections::HashMap;
 use std::vec::Vec;
 
 /// A data flow graph defines all instructions and extended basic blocks in a function as well as

cranelift/codegen/src/lib.rs

@@ -50,7 +50,7 @@ extern crate alloc as std;
 extern crate std;
 
 #[cfg(not(feature = "std"))]
-use hashmap_core::{map as hash_map, HashMap, HashSet};
+use hashbrown::{hash_map, HashMap, HashSet};
 #[cfg(feature = "std")]
 use std::collections::{hash_map, HashMap, HashSet};
 

cranelift/codegen/src/scoped_hash_map.rs

@@ -8,6 +8,11 @@ use crate::fx::FxHashMap;
 use core::hash::Hash;
 use core::mem;
 
+#[cfg(not(feature = "std"))]
+use crate::fx::FxHasher;
+#[cfg(not(feature = "std"))]
+type Hasher = core::hash::BuildHasherDefault<FxHasher>;
+
 struct Val<K, V> {
     value: V,
     next_key: Option<K>,
@@ -16,7 +21,10 @@ struct Val<K, V> {
 
 /// A view into an occupied entry in a `ScopedHashMap`. It is part of the `Entry` enum.
 pub struct OccupiedEntry<'a, K: 'a, V: 'a> {
+    #[cfg(feature = "std")]
     entry: super::hash_map::OccupiedEntry<'a, K, Val<K, V>>,
+    #[cfg(not(feature = "std"))]
+    entry: super::hash_map::OccupiedEntry<'a, K, Val<K, V>, Hasher>,
 }
 
 impl<'a, K, V> OccupiedEntry<'a, K, V> {
@@ -28,12 +36,15 @@ impl<'a, K, V> OccupiedEntry<'a, K, V> {
 
 /// A view into a vacant entry in a `ScopedHashMap`. It is part of the `Entry` enum.
 pub struct VacantEntry<'a, K: 'a, V: 'a> {
+    #[cfg(feature = "std")]
     entry: super::hash_map::VacantEntry<'a, K, Val<K, V>>,
+    #[cfg(not(feature = "std"))]
+    entry: super::hash_map::VacantEntry<'a, K, Val<K, V>, Hasher>,
     next_key: Option<K>,
     depth: usize,
 }
 
-impl<'a, K, V> VacantEntry<'a, K, V> {
+impl<'a, K: Hash, V> VacantEntry<'a, K, V> {
     /// Sets the value of the entry with the `VacantEntry`'s key.
     pub fn insert(self, value: V) {
         self.entry.insert(Val {

cranelift/codegen/src/value_label.rs

@@ -1,11 +1,12 @@
 use crate::ir::{Function, SourceLoc, Value, ValueLabel, ValueLabelAssignments, ValueLoc};
 use crate::isa::TargetIsa;
 use crate::regalloc::{Context, RegDiversions};
-use std::cmp::Ordering;
-use std::collections::{BTreeMap, HashMap};
-use std::iter::Iterator;
-use std::ops::Bound::*;
-use std::ops::Deref;
+use crate::HashMap;
+use core::cmp::Ordering;
+use core::iter::Iterator;
+use core::ops::Bound::*;
+use core::ops::Deref;
+use std::collections::BTreeMap;
 use std::vec::Vec;
 
 #[cfg(feature = "enable-serde")]

cranelift/codegen/src/write.rs

@@ -13,8 +13,8 @@ use crate::ir::{
 use crate::isa::{RegInfo, TargetIsa};
 use crate::packed_option::ReservedValue;
 use crate::value_label::ValueLabelsRanges;
+use crate::HashSet;
 use core::fmt::{self, Write};
-use std::collections::HashSet;
 use std::string::String;
 use std::vec::Vec;