Merge pull request #2857 from workingjubilee/byte-less

Factor out byteorder in cranelift
bytecodealliance · Apr 23, 2021 · 4a830b1 · 4a830b1
2 parents 9637bc5 + a8c956e
commit 4a830b1
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Showing 5 changed files with 26 additions and 31 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/cranelift/codegen/Cargo.toml b/cranelift/codegen/Cargo.toml
@@ -24,7 +24,6 @@ bincode = { version = "1.2.1", optional = true }
 gimli = { version = "0.23.0", default-features = false, features = ["write"], optional = true }
 smallvec = { version = "1.6.1" }
 thiserror = "1.0.4"
-byteorder = { version = "1.3.2", default-features = false }
 peepmatic = { path = "../peepmatic", optional = true, version = "0.73.0" }
 peepmatic-traits = { path = "../peepmatic/crates/traits", optional = true, version = "0.73.0" }
 peepmatic-runtime = { path = "../peepmatic/crates/runtime", optional = true, version = "0.73.0" }

diff --git a/cranelift/codegen/src/isa/unwind/winx64.rs b/cranelift/codegen/src/isa/unwind/winx64.rs
@@ -3,7 +3,6 @@
 use crate::isa::unwind::input;
 use crate::result::{CodegenError, CodegenResult};
 use alloc::vec::Vec;
-use byteorder::{ByteOrder, LittleEndian};
 use log::warn;
 #[cfg(feature = "enable-serde")]
 use serde::{Deserialize, Serialize};
@@ -31,13 +30,13 @@ impl<'a> Writer<'a> {
         self.offset += 1;
     }
 
-    fn write_u16<T: ByteOrder>(&mut self, v: u16) {
-        T::write_u16(&mut self.buf[self.offset..(self.offset + 2)], v);
+    fn write_u16_le(&mut self, v: u16) {
+        self.buf[self.offset..(self.offset + 2)].copy_from_slice(&v.to_le_bytes());
         self.offset += 2;
     }
 
-    fn write_u32<T: ByteOrder>(&mut self, v: u32) {
-        T::write_u32(&mut self.buf[self.offset..(self.offset + 4)], v);
+    fn write_u32_le(&mut self, v: u32) {
+        self.buf[self.offset..(self.offset + 4)].copy_from_slice(&v.to_le_bytes());
         self.offset += 4;
     }
 }
@@ -121,11 +120,11 @@ impl UnwindCode {
                 let scaled_stack_offset = stack_offset / 16;
                 if scaled_stack_offset <= core::u16::MAX as u32 {
                     writer.write_u8((*reg << 4) | (op_small as u8));
-                    writer.write_u16::<LittleEndian>(scaled_stack_offset as u16);
+                    writer.write_u16_le(scaled_stack_offset as u16);
                 } else {
                     writer.write_u8((*reg << 4) | (op_large as u8));
-                    writer.write_u16::<LittleEndian>(*stack_offset as u16);
-                    writer.write_u16::<LittleEndian>((stack_offset >> 16) as u16);
+                    writer.write_u16_le(*stack_offset as u16);
+                    writer.write_u16_le((stack_offset >> 16) as u16);
                 }
             }
             Self::StackAlloc {
@@ -143,10 +142,10 @@ impl UnwindCode {
                     );
                 } else if *size <= LARGE_ALLOC_16BIT_MAX_SIZE {
                     writer.write_u8(UnwindOperation::LargeStackAlloc as u8);
-                    writer.write_u16::<LittleEndian>((*size / 8) as u16);
+                    writer.write_u16_le((*size / 8) as u16);
                 } else {
                     writer.write_u8((1 << 4) | (UnwindOperation::LargeStackAlloc as u8));
-                    writer.write_u32::<LittleEndian>(*size);
+                    writer.write_u32_le(*size);
                 }
             }
             Self::SetFPReg { instruction_offset } => {
@@ -248,7 +247,7 @@ impl UnwindInfo {
 
         // To keep a 32-bit alignment, emit 2 bytes of padding if there's an odd number of 16-bit nodes
         if (node_count & 1) == 1 {
-            writer.write_u16::<LittleEndian>(0);
+            writer.write_u16_le(0);
         }
 
         // Ensure the correct number of bytes was emitted

diff --git a/cranelift/filetests/Cargo.toml b/cranelift/filetests/Cargo.toml
@@ -16,7 +16,6 @@ cranelift-interpreter = { path = "../interpreter", version = "0.73.0" }
 cranelift-native = { path = "../native", version = "0.73.0" }
 cranelift-reader = { path = "../reader", version = "0.73.0" }
 cranelift-preopt = { path = "../preopt", version = "0.73.0" }
-byteorder = { version = "1.3.2", default-features = false }
 file-per-thread-logger = "0.1.2"
 filecheck = "0.5.0"
 gimli = { version = "0.23.0", default-features = false, features = ["read"] }

diff --git a/cranelift/filetests/src/test_unwind.rs b/cranelift/filetests/src/test_unwind.rs
@@ -72,7 +72,6 @@ impl SubTest for TestUnwind {
 }
 
 mod windowsx64 {
-    use byteorder::{ByteOrder, LittleEndian};
     use std::fmt::Write;
 
     pub fn dump<W: Write>(text: &mut W, mem: &[u8]) {
@@ -165,23 +164,24 @@ mod windowsx64 {
             let op_and_info = mem[1];
             let op = UnwindOperation::from(op_and_info & 0xF);
             let info = (op_and_info & 0xF0) >> 4;
-
-            let value = match op {
-                UnwindOperation::LargeStackAlloc => match info {
-                    0 => UnwindValue::U16(LittleEndian::read_u16(&mem[2..])),
-                    1 => UnwindValue::U32(LittleEndian::read_u32(&mem[2..])),
-                    _ => panic!("unexpected stack alloc info value"),
-                },
-                UnwindOperation::SaveNonvolatileRegister => {
-                    UnwindValue::U16(LittleEndian::read_u16(&mem[2..]))
-                }
-                UnwindOperation::SaveNonvolatileRegisterFar => {
-                    UnwindValue::U32(LittleEndian::read_u32(&mem[2..]))
+            let unwind_le_bytes = |bytes| match (bytes, &mem[2..]) {
+                (2, &[b0, b1, ..]) => UnwindValue::U16(u16::from_le_bytes([b0, b1])),
+                (4, &[b0, b1, b2, b3, ..]) => {
+                    UnwindValue::U32(u32::from_le_bytes([b0, b1, b2, b3]))
                 }
-                UnwindOperation::SaveXmm128 => UnwindValue::U16(LittleEndian::read_u16(&mem[2..])),
-                UnwindOperation::SaveXmm128Far => {
-                    UnwindValue::U32(LittleEndian::read_u32(&mem[2..]))
+                (_, _) => panic!("not enough bytes to unwind value"),
+            };
+
+            let value = match (&op, info) {
+                (UnwindOperation::LargeStackAlloc, 0) => unwind_le_bytes(2),
+                (UnwindOperation::LargeStackAlloc, 1) => unwind_le_bytes(4),
+                (UnwindOperation::LargeStackAlloc, _) => {
+                    panic!("unexpected stack alloc info value")
                 }
+                (UnwindOperation::SaveNonvolatileRegister, _) => unwind_le_bytes(2),
+                (UnwindOperation::SaveNonvolatileRegisterFar, _) => unwind_le_bytes(4),
+                (UnwindOperation::SaveXmm128, _) => unwind_le_bytes(2),
+                (UnwindOperation::SaveXmm128Far, _) => unwind_le_bytes(4),
                 _ => UnwindValue::None,
             };