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-rw-r--r--compiler/rustc_serialize/src/opaque.rs750
1 files changed, 750 insertions, 0 deletions
diff --git a/compiler/rustc_serialize/src/opaque.rs b/compiler/rustc_serialize/src/opaque.rs
new file mode 100644
index 000000000..5c17ef6ac
--- /dev/null
+++ b/compiler/rustc_serialize/src/opaque.rs
@@ -0,0 +1,750 @@
+use crate::leb128::{self, max_leb128_len};
+use crate::serialize::{Decodable, Decoder, Encodable, Encoder};
+use std::convert::TryInto;
+use std::fs::File;
+use std::io::{self, Write};
+use std::mem::MaybeUninit;
+use std::path::Path;
+use std::ptr;
+
+// -----------------------------------------------------------------------------
+// Encoder
+// -----------------------------------------------------------------------------
+
+pub struct MemEncoder {
+ pub data: Vec<u8>,
+}
+
+impl MemEncoder {
+ pub fn new() -> MemEncoder {
+ MemEncoder { data: vec![] }
+ }
+
+ #[inline]
+ pub fn position(&self) -> usize {
+ self.data.len()
+ }
+
+ pub fn finish(self) -> Vec<u8> {
+ self.data
+ }
+}
+
+macro_rules! write_leb128 {
+ ($enc:expr, $value:expr, $int_ty:ty, $fun:ident) => {{
+ const MAX_ENCODED_LEN: usize = max_leb128_len!($int_ty);
+ let old_len = $enc.data.len();
+
+ if MAX_ENCODED_LEN > $enc.data.capacity() - old_len {
+ $enc.data.reserve(MAX_ENCODED_LEN);
+ }
+
+ // SAFETY: The above check and `reserve` ensures that there is enough
+ // room to write the encoded value to the vector's internal buffer.
+ unsafe {
+ let buf = &mut *($enc.data.as_mut_ptr().add(old_len)
+ as *mut [MaybeUninit<u8>; MAX_ENCODED_LEN]);
+ let encoded = leb128::$fun(buf, $value);
+ $enc.data.set_len(old_len + encoded.len());
+ }
+ }};
+}
+
+/// A byte that [cannot occur in UTF8 sequences][utf8]. Used to mark the end of a string.
+/// This way we can skip validation and still be relatively sure that deserialization
+/// did not desynchronize.
+///
+/// [utf8]: https://en.wikipedia.org/w/index.php?title=UTF-8&oldid=1058865525#Codepage_layout
+const STR_SENTINEL: u8 = 0xC1;
+
+impl Encoder for MemEncoder {
+ #[inline]
+ fn emit_usize(&mut self, v: usize) {
+ write_leb128!(self, v, usize, write_usize_leb128)
+ }
+
+ #[inline]
+ fn emit_u128(&mut self, v: u128) {
+ write_leb128!(self, v, u128, write_u128_leb128);
+ }
+
+ #[inline]
+ fn emit_u64(&mut self, v: u64) {
+ write_leb128!(self, v, u64, write_u64_leb128);
+ }
+
+ #[inline]
+ fn emit_u32(&mut self, v: u32) {
+ write_leb128!(self, v, u32, write_u32_leb128);
+ }
+
+ #[inline]
+ fn emit_u16(&mut self, v: u16) {
+ self.data.extend_from_slice(&v.to_le_bytes());
+ }
+
+ #[inline]
+ fn emit_u8(&mut self, v: u8) {
+ self.data.push(v);
+ }
+
+ #[inline]
+ fn emit_isize(&mut self, v: isize) {
+ write_leb128!(self, v, isize, write_isize_leb128)
+ }
+
+ #[inline]
+ fn emit_i128(&mut self, v: i128) {
+ write_leb128!(self, v, i128, write_i128_leb128)
+ }
+
+ #[inline]
+ fn emit_i64(&mut self, v: i64) {
+ write_leb128!(self, v, i64, write_i64_leb128)
+ }
+
+ #[inline]
+ fn emit_i32(&mut self, v: i32) {
+ write_leb128!(self, v, i32, write_i32_leb128)
+ }
+
+ #[inline]
+ fn emit_i16(&mut self, v: i16) {
+ self.data.extend_from_slice(&v.to_le_bytes());
+ }
+
+ #[inline]
+ fn emit_i8(&mut self, v: i8) {
+ self.emit_u8(v as u8);
+ }
+
+ #[inline]
+ fn emit_bool(&mut self, v: bool) {
+ self.emit_u8(if v { 1 } else { 0 });
+ }
+
+ #[inline]
+ fn emit_f64(&mut self, v: f64) {
+ let as_u64: u64 = v.to_bits();
+ self.emit_u64(as_u64);
+ }
+
+ #[inline]
+ fn emit_f32(&mut self, v: f32) {
+ let as_u32: u32 = v.to_bits();
+ self.emit_u32(as_u32);
+ }
+
+ #[inline]
+ fn emit_char(&mut self, v: char) {
+ self.emit_u32(v as u32);
+ }
+
+ #[inline]
+ fn emit_str(&mut self, v: &str) {
+ self.emit_usize(v.len());
+ self.emit_raw_bytes(v.as_bytes());
+ self.emit_u8(STR_SENTINEL);
+ }
+
+ #[inline]
+ fn emit_raw_bytes(&mut self, s: &[u8]) {
+ self.data.extend_from_slice(s);
+ }
+}
+
+pub type FileEncodeResult = Result<usize, io::Error>;
+
+// `FileEncoder` encodes data to file via fixed-size buffer.
+//
+// When encoding large amounts of data to a file, using `FileEncoder` may be
+// preferred over using `MemEncoder` to encode to a `Vec`, and then writing the
+// `Vec` to file, as the latter uses as much memory as there is encoded data,
+// while the former uses the fixed amount of memory allocated to the buffer.
+// `FileEncoder` also has the advantage of not needing to reallocate as data
+// is appended to it, but the disadvantage of requiring more error handling,
+// which has some runtime overhead.
+pub struct FileEncoder {
+ // The input buffer. For adequate performance, we need more control over
+ // buffering than `BufWriter` offers. If `BufWriter` ever offers a raw
+ // buffer access API, we can use it, and remove `buf` and `buffered`.
+ buf: Box<[MaybeUninit<u8>]>,
+ buffered: usize,
+ flushed: usize,
+ file: File,
+ // This is used to implement delayed error handling, as described in the
+ // comment on `trait Encoder`.
+ res: Result<(), io::Error>,
+}
+
+impl FileEncoder {
+ pub fn new<P: AsRef<Path>>(path: P) -> io::Result<Self> {
+ const DEFAULT_BUF_SIZE: usize = 8192;
+ FileEncoder::with_capacity(path, DEFAULT_BUF_SIZE)
+ }
+
+ pub fn with_capacity<P: AsRef<Path>>(path: P, capacity: usize) -> io::Result<Self> {
+ // Require capacity at least as large as the largest LEB128 encoding
+ // here, so that we don't have to check or handle this on every write.
+ assert!(capacity >= max_leb128_len());
+
+ // Require capacity small enough such that some capacity checks can be
+ // done using guaranteed non-overflowing add rather than sub, which
+ // shaves an instruction off those code paths (on x86 at least).
+ assert!(capacity <= usize::MAX - max_leb128_len());
+
+ let file = File::create(path)?;
+
+ Ok(FileEncoder {
+ buf: Box::new_uninit_slice(capacity),
+ buffered: 0,
+ flushed: 0,
+ file,
+ res: Ok(()),
+ })
+ }
+
+ #[inline]
+ pub fn position(&self) -> usize {
+ // Tracking position this way instead of having a `self.position` field
+ // means that we don't have to update the position on every write call.
+ self.flushed + self.buffered
+ }
+
+ pub fn flush(&mut self) {
+ // This is basically a copy of `BufWriter::flush`. If `BufWriter` ever
+ // offers a raw buffer access API, we can use it, and remove this.
+
+ /// Helper struct to ensure the buffer is updated after all the writes
+ /// are complete. It tracks the number of written bytes and drains them
+ /// all from the front of the buffer when dropped.
+ struct BufGuard<'a> {
+ buffer: &'a mut [u8],
+ encoder_buffered: &'a mut usize,
+ encoder_flushed: &'a mut usize,
+ flushed: usize,
+ }
+
+ impl<'a> BufGuard<'a> {
+ fn new(
+ buffer: &'a mut [u8],
+ encoder_buffered: &'a mut usize,
+ encoder_flushed: &'a mut usize,
+ ) -> Self {
+ assert_eq!(buffer.len(), *encoder_buffered);
+ Self { buffer, encoder_buffered, encoder_flushed, flushed: 0 }
+ }
+
+ /// The unwritten part of the buffer
+ fn remaining(&self) -> &[u8] {
+ &self.buffer[self.flushed..]
+ }
+
+ /// Flag some bytes as removed from the front of the buffer
+ fn consume(&mut self, amt: usize) {
+ self.flushed += amt;
+ }
+
+ /// true if all of the bytes have been written
+ fn done(&self) -> bool {
+ self.flushed >= *self.encoder_buffered
+ }
+ }
+
+ impl Drop for BufGuard<'_> {
+ fn drop(&mut self) {
+ if self.flushed > 0 {
+ if self.done() {
+ *self.encoder_flushed += *self.encoder_buffered;
+ *self.encoder_buffered = 0;
+ } else {
+ self.buffer.copy_within(self.flushed.., 0);
+ *self.encoder_flushed += self.flushed;
+ *self.encoder_buffered -= self.flushed;
+ }
+ }
+ }
+ }
+
+ // If we've already had an error, do nothing. It'll get reported after
+ // `finish` is called.
+ if self.res.is_err() {
+ return;
+ }
+
+ let mut guard = BufGuard::new(
+ unsafe { MaybeUninit::slice_assume_init_mut(&mut self.buf[..self.buffered]) },
+ &mut self.buffered,
+ &mut self.flushed,
+ );
+
+ while !guard.done() {
+ match self.file.write(guard.remaining()) {
+ Ok(0) => {
+ self.res = Err(io::Error::new(
+ io::ErrorKind::WriteZero,
+ "failed to write the buffered data",
+ ));
+ return;
+ }
+ Ok(n) => guard.consume(n),
+ Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+ Err(e) => {
+ self.res = Err(e);
+ return;
+ }
+ }
+ }
+ }
+
+ pub fn file(&self) -> &File {
+ &self.file
+ }
+
+ #[inline]
+ fn capacity(&self) -> usize {
+ self.buf.len()
+ }
+
+ #[inline]
+ fn write_one(&mut self, value: u8) {
+ // We ensure this during `FileEncoder` construction.
+ debug_assert!(self.capacity() >= 1);
+
+ let mut buffered = self.buffered;
+
+ if std::intrinsics::unlikely(buffered >= self.capacity()) {
+ self.flush();
+ buffered = 0;
+ }
+
+ // SAFETY: The above check and `flush` ensures that there is enough
+ // room to write the input to the buffer.
+ unsafe {
+ *MaybeUninit::slice_as_mut_ptr(&mut self.buf).add(buffered) = value;
+ }
+
+ self.buffered = buffered + 1;
+ }
+
+ #[inline]
+ fn write_all(&mut self, buf: &[u8]) {
+ let capacity = self.capacity();
+ let buf_len = buf.len();
+
+ if std::intrinsics::likely(buf_len <= capacity) {
+ let mut buffered = self.buffered;
+
+ if std::intrinsics::unlikely(buf_len > capacity - buffered) {
+ self.flush();
+ buffered = 0;
+ }
+
+ // SAFETY: The above check and `flush` ensures that there is enough
+ // room to write the input to the buffer.
+ unsafe {
+ let src = buf.as_ptr();
+ let dst = MaybeUninit::slice_as_mut_ptr(&mut self.buf).add(buffered);
+ ptr::copy_nonoverlapping(src, dst, buf_len);
+ }
+
+ self.buffered = buffered + buf_len;
+ } else {
+ self.write_all_unbuffered(buf);
+ }
+ }
+
+ fn write_all_unbuffered(&mut self, mut buf: &[u8]) {
+ // If we've already had an error, do nothing. It'll get reported after
+ // `finish` is called.
+ if self.res.is_err() {
+ return;
+ }
+
+ if self.buffered > 0 {
+ self.flush();
+ }
+
+ // This is basically a copy of `Write::write_all` but also updates our
+ // `self.flushed`. It's necessary because `Write::write_all` does not
+ // return the number of bytes written when an error is encountered, and
+ // without that, we cannot accurately update `self.flushed` on error.
+ while !buf.is_empty() {
+ match self.file.write(buf) {
+ Ok(0) => {
+ self.res = Err(io::Error::new(
+ io::ErrorKind::WriteZero,
+ "failed to write whole buffer",
+ ));
+ return;
+ }
+ Ok(n) => {
+ buf = &buf[n..];
+ self.flushed += n;
+ }
+ Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+ Err(e) => {
+ self.res = Err(e);
+ return;
+ }
+ }
+ }
+ }
+
+ pub fn finish(mut self) -> Result<usize, io::Error> {
+ self.flush();
+
+ let res = std::mem::replace(&mut self.res, Ok(()));
+ res.map(|()| self.position())
+ }
+}
+
+impl Drop for FileEncoder {
+ fn drop(&mut self) {
+ // Likely to be a no-op, because `finish` should have been called and
+ // it also flushes. But do it just in case.
+ let _result = self.flush();
+ }
+}
+
+macro_rules! file_encoder_write_leb128 {
+ ($enc:expr, $value:expr, $int_ty:ty, $fun:ident) => {{
+ const MAX_ENCODED_LEN: usize = max_leb128_len!($int_ty);
+
+ // We ensure this during `FileEncoder` construction.
+ debug_assert!($enc.capacity() >= MAX_ENCODED_LEN);
+
+ let mut buffered = $enc.buffered;
+
+ // This can't overflow. See assertion in `FileEncoder::with_capacity`.
+ if std::intrinsics::unlikely(buffered + MAX_ENCODED_LEN > $enc.capacity()) {
+ $enc.flush();
+ buffered = 0;
+ }
+
+ // SAFETY: The above check and flush ensures that there is enough
+ // room to write the encoded value to the buffer.
+ let buf = unsafe {
+ &mut *($enc.buf.as_mut_ptr().add(buffered) as *mut [MaybeUninit<u8>; MAX_ENCODED_LEN])
+ };
+
+ let encoded = leb128::$fun(buf, $value);
+ $enc.buffered = buffered + encoded.len();
+ }};
+}
+
+impl Encoder for FileEncoder {
+ #[inline]
+ fn emit_usize(&mut self, v: usize) {
+ file_encoder_write_leb128!(self, v, usize, write_usize_leb128)
+ }
+
+ #[inline]
+ fn emit_u128(&mut self, v: u128) {
+ file_encoder_write_leb128!(self, v, u128, write_u128_leb128)
+ }
+
+ #[inline]
+ fn emit_u64(&mut self, v: u64) {
+ file_encoder_write_leb128!(self, v, u64, write_u64_leb128)
+ }
+
+ #[inline]
+ fn emit_u32(&mut self, v: u32) {
+ file_encoder_write_leb128!(self, v, u32, write_u32_leb128)
+ }
+
+ #[inline]
+ fn emit_u16(&mut self, v: u16) {
+ self.write_all(&v.to_le_bytes());
+ }
+
+ #[inline]
+ fn emit_u8(&mut self, v: u8) {
+ self.write_one(v);
+ }
+
+ #[inline]
+ fn emit_isize(&mut self, v: isize) {
+ file_encoder_write_leb128!(self, v, isize, write_isize_leb128)
+ }
+
+ #[inline]
+ fn emit_i128(&mut self, v: i128) {
+ file_encoder_write_leb128!(self, v, i128, write_i128_leb128)
+ }
+
+ #[inline]
+ fn emit_i64(&mut self, v: i64) {
+ file_encoder_write_leb128!(self, v, i64, write_i64_leb128)
+ }
+
+ #[inline]
+ fn emit_i32(&mut self, v: i32) {
+ file_encoder_write_leb128!(self, v, i32, write_i32_leb128)
+ }
+
+ #[inline]
+ fn emit_i16(&mut self, v: i16) {
+ self.write_all(&v.to_le_bytes());
+ }
+
+ #[inline]
+ fn emit_i8(&mut self, v: i8) {
+ self.emit_u8(v as u8);
+ }
+
+ #[inline]
+ fn emit_bool(&mut self, v: bool) {
+ self.emit_u8(if v { 1 } else { 0 });
+ }
+
+ #[inline]
+ fn emit_f64(&mut self, v: f64) {
+ let as_u64: u64 = v.to_bits();
+ self.emit_u64(as_u64);
+ }
+
+ #[inline]
+ fn emit_f32(&mut self, v: f32) {
+ let as_u32: u32 = v.to_bits();
+ self.emit_u32(as_u32);
+ }
+
+ #[inline]
+ fn emit_char(&mut self, v: char) {
+ self.emit_u32(v as u32);
+ }
+
+ #[inline]
+ fn emit_str(&mut self, v: &str) {
+ self.emit_usize(v.len());
+ self.emit_raw_bytes(v.as_bytes());
+ self.emit_u8(STR_SENTINEL);
+ }
+
+ #[inline]
+ fn emit_raw_bytes(&mut self, s: &[u8]) {
+ self.write_all(s);
+ }
+}
+
+// -----------------------------------------------------------------------------
+// Decoder
+// -----------------------------------------------------------------------------
+
+pub struct MemDecoder<'a> {
+ pub data: &'a [u8],
+ position: usize,
+}
+
+impl<'a> MemDecoder<'a> {
+ #[inline]
+ pub fn new(data: &'a [u8], position: usize) -> MemDecoder<'a> {
+ MemDecoder { data, position }
+ }
+
+ #[inline]
+ pub fn position(&self) -> usize {
+ self.position
+ }
+
+ #[inline]
+ pub fn set_position(&mut self, pos: usize) {
+ self.position = pos
+ }
+
+ #[inline]
+ pub fn advance(&mut self, bytes: usize) {
+ self.position += bytes;
+ }
+}
+
+macro_rules! read_leb128 {
+ ($dec:expr, $fun:ident) => {{ leb128::$fun($dec.data, &mut $dec.position) }};
+}
+
+impl<'a> Decoder for MemDecoder<'a> {
+ #[inline]
+ fn read_u128(&mut self) -> u128 {
+ read_leb128!(self, read_u128_leb128)
+ }
+
+ #[inline]
+ fn read_u64(&mut self) -> u64 {
+ read_leb128!(self, read_u64_leb128)
+ }
+
+ #[inline]
+ fn read_u32(&mut self) -> u32 {
+ read_leb128!(self, read_u32_leb128)
+ }
+
+ #[inline]
+ fn read_u16(&mut self) -> u16 {
+ let bytes = [self.data[self.position], self.data[self.position + 1]];
+ let value = u16::from_le_bytes(bytes);
+ self.position += 2;
+ value
+ }
+
+ #[inline]
+ fn read_u8(&mut self) -> u8 {
+ let value = self.data[self.position];
+ self.position += 1;
+ value
+ }
+
+ #[inline]
+ fn read_usize(&mut self) -> usize {
+ read_leb128!(self, read_usize_leb128)
+ }
+
+ #[inline]
+ fn read_i128(&mut self) -> i128 {
+ read_leb128!(self, read_i128_leb128)
+ }
+
+ #[inline]
+ fn read_i64(&mut self) -> i64 {
+ read_leb128!(self, read_i64_leb128)
+ }
+
+ #[inline]
+ fn read_i32(&mut self) -> i32 {
+ read_leb128!(self, read_i32_leb128)
+ }
+
+ #[inline]
+ fn read_i16(&mut self) -> i16 {
+ let bytes = [self.data[self.position], self.data[self.position + 1]];
+ let value = i16::from_le_bytes(bytes);
+ self.position += 2;
+ value
+ }
+
+ #[inline]
+ fn read_i8(&mut self) -> i8 {
+ let value = self.data[self.position];
+ self.position += 1;
+ value as i8
+ }
+
+ #[inline]
+ fn read_isize(&mut self) -> isize {
+ read_leb128!(self, read_isize_leb128)
+ }
+
+ #[inline]
+ fn read_bool(&mut self) -> bool {
+ let value = self.read_u8();
+ value != 0
+ }
+
+ #[inline]
+ fn read_f64(&mut self) -> f64 {
+ let bits = self.read_u64();
+ f64::from_bits(bits)
+ }
+
+ #[inline]
+ fn read_f32(&mut self) -> f32 {
+ let bits = self.read_u32();
+ f32::from_bits(bits)
+ }
+
+ #[inline]
+ fn read_char(&mut self) -> char {
+ let bits = self.read_u32();
+ std::char::from_u32(bits).unwrap()
+ }
+
+ #[inline]
+ fn read_str(&mut self) -> &'a str {
+ let len = self.read_usize();
+ let sentinel = self.data[self.position + len];
+ assert!(sentinel == STR_SENTINEL);
+ let s = unsafe {
+ std::str::from_utf8_unchecked(&self.data[self.position..self.position + len])
+ };
+ self.position += len + 1;
+ s
+ }
+
+ #[inline]
+ fn read_raw_bytes(&mut self, bytes: usize) -> &'a [u8] {
+ let start = self.position;
+ self.position += bytes;
+ &self.data[start..self.position]
+ }
+}
+
+// Specializations for contiguous byte sequences follow. The default implementations for slices
+// encode and decode each element individually. This isn't necessary for `u8` slices when using
+// opaque encoders and decoders, because each `u8` is unchanged by encoding and decoding.
+// Therefore, we can use more efficient implementations that process the entire sequence at once.
+
+// Specialize encoding byte slices. This specialization also applies to encoding `Vec<u8>`s, etc.,
+// since the default implementations call `encode` on their slices internally.
+impl Encodable<MemEncoder> for [u8] {
+ fn encode(&self, e: &mut MemEncoder) {
+ Encoder::emit_usize(e, self.len());
+ e.emit_raw_bytes(self);
+ }
+}
+
+impl Encodable<FileEncoder> for [u8] {
+ fn encode(&self, e: &mut FileEncoder) {
+ Encoder::emit_usize(e, self.len());
+ e.emit_raw_bytes(self);
+ }
+}
+
+// Specialize decoding `Vec<u8>`. This specialization also applies to decoding `Box<[u8]>`s, etc.,
+// since the default implementations call `decode` to produce a `Vec<u8>` internally.
+impl<'a> Decodable<MemDecoder<'a>> for Vec<u8> {
+ fn decode(d: &mut MemDecoder<'a>) -> Self {
+ let len = Decoder::read_usize(d);
+ d.read_raw_bytes(len).to_owned()
+ }
+}
+
+// An integer that will always encode to 8 bytes.
+pub struct IntEncodedWithFixedSize(pub u64);
+
+impl IntEncodedWithFixedSize {
+ pub const ENCODED_SIZE: usize = 8;
+}
+
+impl Encodable<MemEncoder> for IntEncodedWithFixedSize {
+ #[inline]
+ fn encode(&self, e: &mut MemEncoder) {
+ let _start_pos = e.position();
+ e.emit_raw_bytes(&self.0.to_le_bytes());
+ let _end_pos = e.position();
+ debug_assert_eq!((_end_pos - _start_pos), IntEncodedWithFixedSize::ENCODED_SIZE);
+ }
+}
+
+impl Encodable<FileEncoder> for IntEncodedWithFixedSize {
+ #[inline]
+ fn encode(&self, e: &mut FileEncoder) {
+ let _start_pos = e.position();
+ e.emit_raw_bytes(&self.0.to_le_bytes());
+ let _end_pos = e.position();
+ debug_assert_eq!((_end_pos - _start_pos), IntEncodedWithFixedSize::ENCODED_SIZE);
+ }
+}
+
+impl<'a> Decodable<MemDecoder<'a>> for IntEncodedWithFixedSize {
+ #[inline]
+ fn decode(decoder: &mut MemDecoder<'a>) -> IntEncodedWithFixedSize {
+ let _start_pos = decoder.position();
+ let bytes = decoder.read_raw_bytes(IntEncodedWithFixedSize::ENCODED_SIZE);
+ let value = u64::from_le_bytes(bytes.try_into().unwrap());
+ let _end_pos = decoder.position();
+ debug_assert_eq!((_end_pos - _start_pos), IntEncodedWithFixedSize::ENCODED_SIZE);
+
+ IntEncodedWithFixedSize(value)
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-10 12:13:21 +0000