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Do not use LEB128 for encoding u16 and i16 #92314

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merged 1 commit into from
Jan 3, 2022
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Do not use LEB128 for encoding u16 and i16 #92314

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23 changes: 15 additions & 8 deletions compiler/rustc_serialize/src/opaque.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -92,7 +92,8 @@ impl serialize::Encoder for Encoder {

#[inline]
fn emit_u16(&mut self, v: u16) -> EncodeResult {
write_leb128!(self, v, u16, write_u16_leb128)
self.data.extend_from_slice(&v.to_le_bytes());
Ok(())
}

#[inline]
Expand Down Expand Up @@ -123,7 +124,8 @@ impl serialize::Encoder for Encoder {

#[inline]
fn emit_i16(&mut self, v: i16) -> EncodeResult {
write_leb128!(self, v, i16, write_i16_leb128)
self.data.extend_from_slice(&v.to_le_bytes());
Ok(())
}

#[inline]
Expand Down Expand Up @@ -446,7 +448,7 @@ impl serialize::Encoder for FileEncoder {

#[inline]
fn emit_u16(&mut self, v: u16) -> FileEncodeResult {
file_encoder_write_leb128!(self, v, u16, write_u16_leb128)
self.write_all(&v.to_le_bytes())
}

#[inline]
Expand Down Expand Up @@ -476,13 +478,12 @@ impl serialize::Encoder for FileEncoder {

#[inline]
fn emit_i16(&mut self, v: i16) -> FileEncodeResult {
file_encoder_write_leb128!(self, v, i16, write_i16_leb128)
self.write_all(&v.to_le_bytes())
}

#[inline]
fn emit_i8(&mut self, v: i8) -> FileEncodeResult {
let as_u8: u8 = unsafe { std::mem::transmute(v) };
self.emit_u8(as_u8)
self.emit_u8(v as u8)
}

#[inline]
Expand Down Expand Up @@ -591,7 +592,10 @@ impl<'a> serialize::Decoder for Decoder<'a> {

#[inline]
fn read_u16(&mut self) -> Result<u16, Self::Error> {
read_leb128!(self, read_u16_leb128)
let bytes = [self.data[self.position], self.data[self.position + 1]];
let value = u16::from_le_bytes(bytes);
self.position += 2;
Ok(value)
}

#[inline]
Expand Down Expand Up @@ -623,7 +627,10 @@ impl<'a> serialize::Decoder for Decoder<'a> {

#[inline]
fn read_i16(&mut self) -> Result<i16, Self::Error> {
read_leb128!(self, read_i16_leb128)
let bytes = [self.data[self.position], self.data[self.position + 1]];
let value = i16::from_le_bytes(bytes);
self.position += 2;
Ok(value)
}

#[inline]
Expand Down