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-rw-r--r--src/display.rs1076
1 files changed, 0 insertions, 1076 deletions
diff --git a/src/display.rs b/src/display.rs
index 9b72cb3..e69de29 100644
--- a/src/display.rs
+++ b/src/display.rs
@@ -1,1076 +0,0 @@
-use core::fmt;
-
-use crate::safer_unchecked::unreachable_kinda_unchecked;
-
-extern crate alloc;
-
-// TODO: find a better place to put this....
-fn c_to_hex(c: u8) -> u8 {
- /*
- static CHARSET: &'static [u8; 16] = b"0123456789abcdef";
- CHARSET[c as usize]
- */
- // the conditional branch below is faster than a lookup, yes
- if c < 10 {
- b'0' + c
- } else {
- b'a' + c - 10
- }
-}
-
-pub enum TokenType {
- Mnemonic,
- Operand,
- Immediate,
- Register,
- Offset,
-}
-
-/// `DisplaySink` allows client code to collect output and minimal markup. this is currently used
-/// in formatting instructions for two reasons:
-/// * `DisplaySink` implementations have the opportunity to collect starts and ends of tokens at
-/// the same time as collecting output itself.
-/// * `DisplaySink` implementations provides specialized functions for writing strings in
-/// circumstances where a simple "use `core::fmt`" might incur unwanted overhead.
-///
-/// spans are reported through `span_start` and `span_exit` to avoid constraining implementations
-/// into tracking current output offset (which may not be knowable) or span size (which may be
-/// knowable, but incur additional overhead to compute or track).
-///
-/// spans are entered and exited in a FILO manner: a function writing to some `DisplaySink` must
-/// exit spans in reverse order to when they are entered. a function sequence like
-/// `sink.span_start(Operand); sink.span_start(Immediate); sink.span_exit(Operand)` is in error.
-///
-/// the `write_*` helpers on `DisplaySink` may be able to take advantage of contraints described in
-/// documentation here to better support writing some kinds of inputs than a fully-general solution
-/// (such as `core::fmt`) might be able to yield.
-///
-/// currently there are two motivating factors for `write_*` helpers:
-///
-/// instruction formatting often involves writing small but variable-size strings, such as register
-/// names, which is something of a pathological case for string appending as Rust currently exists:
-/// this often becomes `memcpy` and specifically a call to the platform's `memcpy` (rather than an
-/// inlined `rep movsb`) just to move 3-5 bytes. one relevant Rust issue for reference:
-/// https://github.com/rust-lang/rust/issues/92993#issuecomment-2028915232
-///
-/// there are similar papercuts around formatting integers as base-16 numbers, such as
-/// https://github.com/rust-lang/rust/pull/122770 . in isolation and in most applications these are
-/// not a significant source of overhead. but for programs bounded on decoding and printing
-/// instructions, these can add up to significant overhead - on the order of 10-20% of total
-/// runtime.
-///
-/// `DisplaySink`
-pub trait DisplaySink: fmt::Write {
- #[inline(always)]
- fn write_fixed_size(&mut self, s: &str) -> Result<(), core::fmt::Error> {
- self.write_str(s)
- }
-
- /// write a string to this sink that is less than 32 bytes. this is provided for optimization
- /// opportunities when writing a variable-length string with known max size.
- ///
- /// SAFETY: the provided `s` must be less than 32 bytes. if the provided string is longer than
- /// 31 bytes, implementations may only copy part of a multi-byte codepoint while writing to a
- /// utf-8 string. this may corrupt Rust strings.
- unsafe fn write_lt_32(&mut self, s: &str) -> Result<(), core::fmt::Error> {
- self.write_str(s)
- }
- /// write a string to this sink that is less than 16 bytes. this is provided for optimization
- /// opportunities when writing a variable-length string with known max size.
- ///
- /// SAFETY: the provided `s` must be less than 16 bytes. if the provided string is longer than
- /// 15 bytes, implementations may only copy part of a multi-byte codepoint while writing to a
- /// utf-8 string. this may corrupt Rust strings.
- unsafe fn write_lt_16(&mut self, s: &str) -> Result<(), core::fmt::Error> {
- self.write_str(s)
- }
- /// write a string to this sink that is less than 8 bytes. this is provided for optimization
- /// opportunities when writing a variable-length string with known max size.
- ///
- /// SAFETY: the provided `s` must be less than 8 bytes. if the provided string is longer than
- /// 7 bytes, implementations may only copy part of a multi-byte codepoint while writing to a
- /// utf-8 string. this may corrupt Rust strings.
- unsafe fn write_lt_8(&mut self, s: &str) -> Result<(), core::fmt::Error> {
- self.write_str(s)
- }
-
- /// write a u8 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- fn write_u8(&mut self, v: u8) -> Result<(), core::fmt::Error> {
- write!(self, "{:x}", v)
- }
- /// write a u16 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- fn write_u16(&mut self, v: u16) -> Result<(), core::fmt::Error> {
- write!(self, "{:x}", v)
- }
- /// write a u32 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- fn write_u32(&mut self, v: u32) -> Result<(), core::fmt::Error> {
- write!(self, "{:x}", v)
- }
- /// write a u64 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- fn write_u64(&mut self, v: u64) -> Result<(), core::fmt::Error> {
- write!(self, "{:x}", v)
- }
- /// enter a region inside which output corresponds to a `ty`.
- ///
- /// the default implementation of these functions is as a no-op. this way, providing span
- /// information to a `DisplaySink` that does not want it is eliminated at compile time.
- ///
- /// spans are entered and ended in a FILO manner: a function writing to some `DisplaySink` must
- /// end spans in reverse order to when they are entered. a function sequence like
- /// `sink.span_start(Operand); sink.span_start(Immediate); sink.span_end(Operand)` is in error.
- ///
- /// a simple use of `span_start`/`span_end` might look something like:
- /// ```compile_fail
- /// sink.span_start(Operand)
- /// sink.write_char('[')
- /// sink.span_start(Register)
- /// sink.write_fixed_size("rbp")
- /// sink.span_end(Register)
- /// sink.write_char(']')
- /// sink.span_end(Operand)
- /// ```
- /// which writes the text `[rbp]`, with span indicators where the operand (`[ ... ]`) begins,
- /// as well as the start and end of a register name.
- fn span_start(&mut self, _ty: TokenType) { }
- /// end a region where a `ty` was written. see docs on [`DisplaySink::span_start`] for more.
- fn span_end(&mut self, _ty: TokenType) { }
-}
-
-pub struct NoColorsSink<'a, T: fmt::Write> {
- pub out: &'a mut T,
-}
-
-impl<'a, T: fmt::Write> DisplaySink for NoColorsSink<'a, T> {
- fn span_start(&mut self, _ty: TokenType) { }
- fn span_end(&mut self, _ty: TokenType) { }
-}
-
-impl<'a, T: fmt::Write> fmt::Write for NoColorsSink<'a, T> {
- fn write_str(&mut self, s: &str) -> Result<(), core::fmt::Error> {
- self.out.write_str(s)
- }
- fn write_char(&mut self, c: char) -> Result<(), core::fmt::Error> {
- self.out.write_char(c)
- }
- fn write_fmt(&mut self, f: fmt::Arguments) -> Result<(), core::fmt::Error> {
- self.out.write_fmt(f)
- }
-}
-
-/// this is an implementation detail of yaxpeax-arch and related crates. if you are a user of the
-/// disassemblers, do not use this struct. do not depend on this struct existing. this struct is
-/// not stable. this struct is not safe for general use. if you use this struct you and your
-/// program will be eaten by gremlins.
-///
-/// if you are implementing an instruction formatter for the yaxpeax family of crates: this struct
-/// is guaranteed to contain a string that is long enough to hold a fully-formatted instruction.
-/// because the buffer is guaranteed to be long enough, writes through `InstructionTextSink` are
-/// not bounds-checked, and the buffer is never grown.
-///
-/// this is wildly dangerous in general use. the public constructor of `InstructionTextSink` is
-/// unsafe as a result. as used in `InstructionFormatter`, the buffer is guaranteed to be
-/// `clear()`ed before use, `InstructionFormatter` ensures the buffer is large enough, *and*
-/// `InstructionFormatter` never allows `InstructionTextSink` to exist in a context where it would
-/// be written to without being rewound first.
-///
-/// because this opens a very large hole through which `fmt::Write` can become unsafe, incorrect
-/// uses of this struct will be hard to debug in general. `InstructionFormatter` is probably at the
-/// limit of easily-reasoned-about lifecycle of the buffer, which "only" leaves the problem of
-/// ensuring that instruction formatting impls this buffer is passed to are appropriately sized.
-///
-/// this is intended to be hidden in docs. if you see this in docs, it's a bug.
-#[doc(hidden)]
-pub(crate) struct InstructionTextSink<'buf> {
- buf: &'buf mut alloc::string::String
-}
-
-impl<'buf> InstructionTextSink<'buf> {
- pub unsafe fn new(buf: &'buf mut alloc::string::String) -> Self {
- Self { buf }
- }
-}
-
-impl<'buf> fmt::Write for InstructionTextSink<'buf> {
- fn write_str(&mut self, s: &str) -> Result<(), core::fmt::Error> {
- self.buf.write_str(s)
- }
- fn write_char(&mut self, c: char) -> Result<(), core::fmt::Error> {
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + 1 {
- panic!("InstructionTextSink::write_char would overflow output");
- }
- }
- // SAFETY: `buf` is assumed to be long enough to hold all input, `buf` at `underlying.len()`
- // is valid for writing, but may be uninitialized.
- //
- // this function is essentially equivalent to `Vec::push` specialized for the case that
- // `len < buf.capacity()`:
- // https://github.com/rust-lang/rust/blob/be9e27e/library/alloc/src/vec/mod.rs#L1993-L2006
- unsafe {
- let underlying = self.buf.as_mut_vec();
- // `InstructionTextSink::write_char` is only used by yaxpeax-x86, and is only used to
- // write single ASCII characters. this is wrong in the general case, but `write_char`
- // here is not going to be used in the general case.
- if cfg!(debug_asertions) {
- panic!("InstructionTextSink::write_char would truncate output");
- }
- let to_push = c as u8;
- // `ptr::write` here because `underlying.add(underlying.len())` may not point to an
- // initialized value, which would mean that turning that pointer into a `&mut u8` to
- // store through would be UB. `ptr::write` avoids taking the mut ref.
- underlying.as_mut_ptr().offset(underlying.len() as isize).write(to_push);
- // we have initialized all (one) bytes that `set_len` is increasing the length to
- // include.
- underlying.set_len(underlying.len() + 1);
- }
- Ok(())
- }
-}
-
-/// this DisplaySink impl exists to support somewhat more performant buffering of the kinds of
-/// strings `yaxpeax-x86` uses in formatting instructions.
-impl DisplaySink for alloc::string::String {
- #[inline(always)]
- fn write_fixed_size(&mut self, s: &str) -> Result<(), core::fmt::Error> {
- self.reserve(s.len());
- let buf = unsafe { self.as_mut_vec() };
- let new_bytes = s.as_bytes();
-
- if new_bytes.len() == 0 {
- unsafe { unreachable_kinda_unchecked() }
- }
-
- if new_bytes.len() >= 16 {
- unsafe { unreachable_kinda_unchecked() }
- }
-
- unsafe {
- let dest = buf.as_mut_ptr().offset(buf.len() as isize);
-
- // this used to be enough to bamboozle llvm away from
- // https://github.com/rust-lang/rust/issues/92993#issuecomment-2028915232
- // if `s` is not fixed size. somewhere between Rust 1.68 and Rust 1.74 this stopped
- // being sufficient, so `write_fixed_size` truly should only be used for fixed size `s`
- // (otherwise this is a libc memcpy call in disguise). for fixed-size strings this
- // unrolls into some kind of appropriate series of `mov`.
- dest.offset(0 as isize).write(new_bytes[0]);
- for i in 1..new_bytes.len() {
- dest.offset(i as isize).write(new_bytes[i]);
- }
-
- buf.set_len(buf.len() + new_bytes.len());
- }
-
- Ok(())
- }
- unsafe fn write_lt_32(&mut self, s: &str) -> Result<(), fmt::Error> {
- self.reserve(s.len());
-
- // SAFETY: todo
- let buf = unsafe { self.as_mut_vec() };
- let new_bytes = s.as_bytes();
-
- // should get DCE
- if new_bytes.len() >= 32 {
- unsafe { core::hint::unreachable_unchecked() }
- }
-
- unsafe {
- let dest = buf.as_mut_ptr().offset(buf.len() as isize);
- let src = new_bytes.as_ptr();
-
- let rem = new_bytes.len() as isize;
-
- // set_len early because there is no way to avoid the following asm!() writing that
- // same number of bytes into buf
- buf.set_len(buf.len() + new_bytes.len());
-
- core::arch::asm!(
- "6:",
- "cmp {rem:e}, 16",
- "jb 7f",
- "mov {buf:r}, qword ptr [{src} + {rem} - 16]",
- "mov qword ptr [{dest} + {rem} - 16], {buf:r}",
- "mov {buf:r}, qword ptr [{src} + {rem} - 8]",
- "mov qword ptr [{dest} + {rem} - 8], {buf:r}",
- "sub {rem:e}, 16",
- "jz 11f",
- "7:",
- "cmp {rem:e}, 8",
- "jb 8f",
- "mov {buf:r}, qword ptr [{src} + {rem} - 8]",
- "mov qword ptr [{dest} + {rem} - 8], {buf:r}",
- "sub {rem:e}, 8",
- "jz 11f",
- "8:",
- "cmp {rem:e}, 4",
- "jb 9f",
- "mov {buf:e}, dword ptr [{src} + {rem} - 4]",
- "mov dword ptr [{dest} + {rem} - 4], {buf:e}",
- "sub {rem:e}, 4",
- "jz 11f",
- "9:",
- "cmp {rem:e}, 2",
- "jb 10f",
- "mov {buf:x}, word ptr [{src} + {rem} - 2]",
- "mov word ptr [{dest} + {rem} - 2], {buf:x}",
- "sub {rem:e}, 2",
- "jz 11f",
- "10:",
- "cmp {rem:e}, 1",
- "jb 11f",
- "mov {buf:l}, byte ptr [{src} + {rem} - 1]",
- "mov byte ptr [{dest} + {rem} - 1], {buf:l}",
- "11:",
- src = in(reg) src,
- dest = in(reg) dest,
- rem = inout(reg) rem => _,
- buf = out(reg) _,
- options(nostack),
- );
- }
- /*
- for i in 0..new_bytes.len() {
- unsafe {
- buf.as_mut_ptr().offset(buf.len() as isize).offset(i as isize).write_volatile(new_bytes[i]);
- }
- }
- */
-
- Ok(())
- }
- unsafe fn write_lt_16(&mut self, s: &str) -> Result<(), fmt::Error> {
- self.reserve(s.len());
-
- // SAFETY: todo
- let buf = unsafe { self.as_mut_vec() };
- let new_bytes = s.as_bytes();
-
- // should get DCE
- if new_bytes.len() >= 16 {
- unsafe { core::hint::unreachable_unchecked() }
- }
-
- unsafe {
- let dest = buf.as_mut_ptr().offset(buf.len() as isize);
- let src = new_bytes.as_ptr();
-
- let rem = new_bytes.len() as isize;
-
- // set_len early because there is no way to avoid the following asm!() writing that
- // same number of bytes into buf
- buf.set_len(buf.len() + new_bytes.len());
-
- core::arch::asm!(
- "7:",
- "cmp {rem:e}, 8",
- "jb 8f",
- "mov {buf:r}, qword ptr [{src} + {rem} - 8]",
- "mov qword ptr [{dest} + {rem} - 8], {buf:r}",
- "sub {rem:e}, 8",
- "jz 11f",
- "8:",
- "cmp {rem:e}, 4",
- "jb 9f",
- "mov {buf:e}, dword ptr [{src} + {rem} - 4]",
- "mov dword ptr [{dest} + {rem} - 4], {buf:e}",
- "sub {rem:e}, 4",
- "jz 11f",
- "9:",
- "cmp {rem:e}, 2",
- "jb 10f",
- "mov {buf:x}, word ptr [{src} + {rem} - 2]",
- "mov word ptr [{dest} + {rem} - 2], {buf:x}",
- "sub {rem:e}, 2",
- "jz 11f",
- "10:",
- "cmp {rem:e}, 1",
- "jb 11f",
- "mov {buf:l}, byte ptr [{src} + {rem} - 1]",
- "mov byte ptr [{dest} + {rem} - 1], {buf:l}",
- "11:",
- src = in(reg) src,
- dest = in(reg) dest,
- rem = inout(reg) rem => _,
- buf = out(reg) _,
- options(nostack),
- );
- }
- /*
- for i in 0..new_bytes.len() {
- unsafe {
- buf.as_mut_ptr().offset(buf.len() as isize).offset(i as isize).write_volatile(new_bytes[i]);
- }
- }
- */
-
- Ok(())
- }
- unsafe fn write_lt_8(&mut self, s: &str) -> Result<(), fmt::Error> {
- self.reserve(s.len());
-
- // SAFETY: todo
- let buf = unsafe { self.as_mut_vec() };
- let new_bytes = s.as_bytes();
-
- // should get DCE
- if new_bytes.len() >= 8 {
- unsafe { core::hint::unreachable_unchecked() }
- }
-
- unsafe {
- let dest = buf.as_mut_ptr().offset(buf.len() as isize);
- let src = new_bytes.as_ptr();
-
- let rem = new_bytes.len() as isize;
-
- // set_len early because there is no way to avoid the following asm!() writing that
- // same number of bytes into buf
- buf.set_len(buf.len() + new_bytes.len());
-
- core::arch::asm!(
- "8:",
- "cmp {rem:e}, 4",
- "jb 9f",
- "mov {buf:e}, dword ptr [{src} + {rem} - 4]",
- "mov dword ptr [{dest} + {rem} - 4], {buf:e}",
- "sub {rem:e}, 4",
- "jz 11f",
- "9:",
- "cmp {rem:e}, 2",
- "jb 10f",
- "mov {buf:x}, word ptr [{src} + {rem} - 2]",
- "mov word ptr [{dest} + {rem} - 2], {buf:x}",
- "sub {rem:e}, 2",
- "jz 11f",
- "10:",
- "cmp {rem:e}, 1",
- "jb 11f",
- "mov {buf:l}, byte ptr [{src} + {rem} - 1]",
- "mov byte ptr [{dest} + {rem} - 1], {buf:l}",
- "11:",
- src = in(reg) src,
- dest = in(reg) dest,
- rem = inout(reg) rem => _,
- buf = out(reg) _,
- options(nostack),
- );
- }
- /*
- for i in 0..new_bytes.len() {
- unsafe {
- buf.as_mut_ptr().offset(buf.len() as isize).offset(i as isize).write_volatile(new_bytes[i]);
- }
- }
- */
-
- Ok(())
- }
- /// write a u8 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- #[inline(always)]
- fn write_u8(&mut self, mut v: u8) -> Result<(), core::fmt::Error> {
- if v == 0 {
- return self.write_fixed_size("0");
- }
- // we can fairly easily predict the size of a formatted string here with lzcnt, which also
- // means we can write directly into the correct offsets of the output string.
- let printed_size = ((8 - v.leading_zeros() + 3) >> 2) as usize;
-
- self.reserve(printed_size);
-
- let buf = unsafe { self.as_mut_vec() };
- let new_len = buf.len() + printed_size;
-
- unsafe {
- buf.set_len(new_len);
- }
- let mut p = unsafe { buf.as_mut_ptr().offset(new_len as isize) };
-
- loop {
- let digit = v % 16;
- let c = c_to_hex(digit as u8);
- unsafe {
- p = p.offset(-1);
- p.write(c);
- }
- v = v / 16;
- if v == 0 {
- break;
- }
- }
-
- Ok(())
- }
- /// write a u16 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- #[inline(always)]
- fn write_u16(&mut self, mut v: u16) -> Result<(), core::fmt::Error> {
- if v == 0 {
- return self.write_fixed_size("0");
- }
- // we can fairly easily predict the size of a formatted string here with lzcnt, which also
- // means we can write directly into the correct offsets of the output string.
- let printed_size = ((16 - v.leading_zeros() + 3) >> 2) as usize;
-
- self.reserve(printed_size);
-
- let buf = unsafe { self.as_mut_vec() };
- let new_len = buf.len() + printed_size;
-
- unsafe {
- buf.set_len(new_len);
- }
- let mut p = unsafe { buf.as_mut_ptr().offset(new_len as isize) };
-
- loop {
- let digit = v % 16;
- let c = c_to_hex(digit as u8);
- unsafe {
- p = p.offset(-1);
- p.write(c);
- }
- v = v / 16;
- if v == 0 {
- break;
- }
- }
-
- Ok(())
- }
- /// write a u32 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- #[inline(always)]
- fn write_u32(&mut self, mut v: u32) -> Result<(), core::fmt::Error> {
- if v == 0 {
- return self.write_fixed_size("0");
- }
- // we can fairly easily predict the size of a formatted string here with lzcnt, which also
- // means we can write directly into the correct offsets of the output string.
- let printed_size = ((32 - v.leading_zeros() + 3) >> 2) as usize;
-
- self.reserve(printed_size);
-
- let buf = unsafe { self.as_mut_vec() };
- let new_len = buf.len() + printed_size;
-
- unsafe {
- buf.set_len(new_len);
- }
- let mut p = unsafe { buf.as_mut_ptr().offset(new_len as isize) };
-
- loop {
- let digit = v % 16;
- let c = c_to_hex(digit as u8);
- unsafe {
- p = p.offset(-1);
- p.write(c);
- }
- v = v / 16;
- if v == 0 {
- break;
- }
- }
-
- Ok(())
- }
- /// write a u64 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- #[inline(always)]
- fn write_u64(&mut self, mut v: u64) -> Result<(), core::fmt::Error> {
- if v == 0 {
- return self.write_fixed_size("0");
- }
- // we can fairly easily predict the size of a formatted string here with lzcnt, which also
- // means we can write directly into the correct offsets of the output string.
- let printed_size = ((64 - v.leading_zeros() + 3) >> 2) as usize;
-
- self.reserve(printed_size);
-
- let buf = unsafe { self.as_mut_vec() };
- let new_len = buf.len() + printed_size;
-
- unsafe {
- buf.set_len(new_len);
- }
- let mut p = unsafe { buf.as_mut_ptr().offset(new_len as isize) };
-
- loop {
- let digit = v % 16;
- let c = c_to_hex(digit as u8);
- unsafe {
- p = p.offset(-1);
- p.write(c);
- }
- v = v / 16;
- if v == 0 {
- break;
- }
- }
-
- Ok(())
- }
- fn span_start(&mut self, _ty: TokenType) {}
- fn span_end(&mut self, _ty: TokenType) {}
-}
-
-impl<'buf> DisplaySink for InstructionTextSink<'buf> {
- #[inline(always)]
- fn write_fixed_size(&mut self, s: &str) -> Result<(), core::fmt::Error> {
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + s.len() {
- panic!("InstructionTextSink::write_fixed_size would overflow output");
- }
- }
-
- let buf = unsafe { self.buf.as_mut_vec() };
- let new_bytes = s.as_bytes();
-
- if new_bytes.len() == 0 {
- return Ok(());
- }
-
- if new_bytes.len() >= 16 {
- unsafe { unreachable_kinda_unchecked() }
- }
-
- unsafe {
- let dest = buf.as_mut_ptr().offset(buf.len() as isize);
-
- // this used to be enough to bamboozle llvm away from
- // https://github.com/rust-lang/rust/issues/92993#issuecomment-2028915232https://github.com/rust-lang/rust/issues/92993#issuecomment-2028915232
- // if `s` is not fixed size. somewhere between Rust 1.68 and Rust 1.74 this stopped
- // being sufficient, so `write_fixed_size` truly should only be used for fixed size `s`
- // (otherwise this is a libc memcpy call in disguise). for fixed-size strings this
- // unrolls into some kind of appropriate series of `mov`.
- dest.offset(0 as isize).write(new_bytes[0]);
- for i in 1..new_bytes.len() {
- dest.offset(i as isize).write(new_bytes[i]);
- }
-
- buf.set_len(buf.len() + new_bytes.len());
- }
-
- Ok(())
- }
- unsafe fn write_lt_32(&mut self, s: &str) -> Result<(), fmt::Error> {
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + s.len() {
- panic!("InstructionTextSink::write_lt_32 would overflow output");
- }
- }
-
- // SAFETY: todo
- let buf = unsafe { self.buf.as_mut_vec() };
- let new_bytes = s.as_bytes();
-
- // should get DCE
- if new_bytes.len() >= 32 {
- unsafe { core::hint::unreachable_unchecked() }
- }
-
- unsafe {
- let dest = buf.as_mut_ptr().offset(buf.len() as isize);
- let src = new_bytes.as_ptr();
-
- let rem = new_bytes.len() as isize;
-
- // set_len early because there is no way to avoid the following asm!() writing that
- // same number of bytes into buf
- buf.set_len(buf.len() + new_bytes.len());
-
- core::arch::asm!(
- "6:",
- "cmp {rem:e}, 16",
- "jb 7f",
- "mov {buf:r}, qword ptr [{src} + {rem} - 16]",
- "mov qword ptr [{dest} + {rem} - 16], {buf:r}",
- "mov {buf:r}, qword ptr [{src} + {rem} - 8]",
- "mov qword ptr [{dest} + {rem} - 8], {buf:r}",
- "sub {rem:e}, 16",
- "jz 11f",
- "7:",
- "cmp {rem:e}, 8",
- "jb 8f",
- "mov {buf:r}, qword ptr [{src} + {rem} - 8]",
- "mov qword ptr [{dest} + {rem} - 8], {buf:r}",
- "sub {rem:e}, 8",
- "jz 11f",
- "8:",
- "cmp {rem:e}, 4",
- "jb 9f",
- "mov {buf:e}, dword ptr [{src} + {rem} - 4]",
- "mov dword ptr [{dest} + {rem} - 4], {buf:e}",
- "sub {rem:e}, 4",
- "jz 11f",
- "9:",
- "cmp {rem:e}, 2",
- "jb 10f",
- "mov {buf:x}, word ptr [{src} + {rem} - 2]",
- "mov word ptr [{dest} + {rem} - 2], {buf:x}",
- "sub {rem:e}, 2",
- "jz 11f",
- "10:",
- "cmp {rem:e}, 1",
- "jb 11f",
- "mov {buf:l}, byte ptr [{src} + {rem} - 1]",
- "mov byte ptr [{dest} + {rem} - 1], {buf:l}",
- "11:",
- src = in(reg) src,
- dest = in(reg) dest,
- rem = inout(reg) rem => _,
- buf = out(reg) _,
- options(nostack),
- );
- }
- /*
- for i in 0..new_bytes.len() {
- unsafe {
- buf.as_mut_ptr().offset(buf.len() as isize).offset(i as isize).write_volatile(new_bytes[i]);
- }
- }
- */
-
- Ok(())
- }
- unsafe fn write_lt_16(&mut self, s: &str) -> Result<(), fmt::Error> {
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + s.len() {
- panic!("InstructionTextSink::write_lt_16 would overflow output");
- }
- }
-
- // SAFETY: todo
- let buf = unsafe { self.buf.as_mut_vec() };
- let new_bytes = s.as_bytes();
-
- // should get DCE
- if new_bytes.len() >= 16 {
- unsafe { core::hint::unreachable_unchecked() }
- }
-
- unsafe {
- let dest = buf.as_mut_ptr().offset(buf.len() as isize);
- let src = new_bytes.as_ptr();
-
- let rem = new_bytes.len() as isize;
-
- // set_len early because there is no way to avoid the following asm!() writing that
- // same number of bytes into buf
- buf.set_len(buf.len() + new_bytes.len());
-
- core::arch::asm!(
- "7:",
- "cmp {rem:e}, 8",
- "jb 8f",
- "mov {buf:r}, qword ptr [{src} + {rem} - 8]",
- "mov qword ptr [{dest} + {rem} - 8], {buf:r}",
- "sub {rem:e}, 8",
- "jz 11f",
- "8:",
- "cmp {rem:e}, 4",
- "jb 9f",
- "mov {buf:e}, dword ptr [{src} + {rem} - 4]",
- "mov dword ptr [{dest} + {rem} - 4], {buf:e}",
- "sub {rem:e}, 4",
- "jz 11f",
- "9:",
- "cmp {rem:e}, 2",
- "jb 10f",
- "mov {buf:x}, word ptr [{src} + {rem} - 2]",
- "mov word ptr [{dest} + {rem} - 2], {buf:x}",
- "sub {rem:e}, 2",
- "jz 11f",
- "10:",
- "cmp {rem:e}, 1",
- "jb 11f",
- "mov {buf:l}, byte ptr [{src} + {rem} - 1]",
- "mov byte ptr [{dest} + {rem} - 1], {buf:l}",
- "11:",
- src = in(reg) src,
- dest = in(reg) dest,
- rem = inout(reg) rem => _,
- buf = out(reg) _,
- options(nostack),
- );
- }
- /*
- for i in 0..new_bytes.len() {
- unsafe {
- buf.as_mut_ptr().offset(buf.len() as isize).offset(i as isize).write_volatile(new_bytes[i]);
- }
- }
- */
-
- Ok(())
- }
- unsafe fn write_lt_8(&mut self, s: &str) -> Result<(), fmt::Error> {
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + s.len() {
- panic!("InstructionTextSink::write_lt_8 would overflow output");
- }
- }
-
- // SAFETY: todo
- let buf = unsafe { self.buf.as_mut_vec() };
- let new_bytes = s.as_bytes();
-
- // should get DCE
- if new_bytes.len() >= 8 {
- unsafe { core::hint::unreachable_unchecked() }
- }
-
- unsafe {
- let dest = buf.as_mut_ptr().offset(buf.len() as isize);
- let src = new_bytes.as_ptr();
-
- let rem = new_bytes.len() as isize;
-
- // set_len early because there is no way to avoid the following asm!() writing that
- // same number of bytes into buf
- buf.set_len(buf.len() + new_bytes.len());
-
- core::arch::asm!(
- "8:",
- "cmp {rem:e}, 4",
- "jb 9f",
- "mov {buf:e}, dword ptr [{src} + {rem} - 4]",
- "mov dword ptr [{dest} + {rem} - 4], {buf:e}",
- "sub {rem:e}, 4",
- "jz 11f",
- "9:",
- "cmp {rem:e}, 2",
- "jb 10f",
- "mov {buf:x}, word ptr [{src} + {rem} - 2]",
- "mov word ptr [{dest} + {rem} - 2], {buf:x}",
- "sub {rem:e}, 2",
- "jz 11f",
- "10:",
- "cmp {rem:e}, 1",
- "jb 11f",
- "mov {buf:l}, byte ptr [{src} + {rem} - 1]",
- "mov byte ptr [{dest} + {rem} - 1], {buf:l}",
- "11:",
- src = in(reg) src,
- dest = in(reg) dest,
- rem = inout(reg) rem => _,
- buf = out(reg) _,
- options(nostack),
- );
- }
- /*
- for i in 0..new_bytes.len() {
- unsafe {
- buf.as_mut_ptr().offset(buf.len() as isize).offset(i as isize).write_volatile(new_bytes[i]);
- }
- }
- */
-
- Ok(())
- }
- /// write a u8 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- #[inline(always)]
- fn write_u8(&mut self, mut v: u8) -> Result<(), core::fmt::Error> {
- if v == 0 {
- return self.write_fixed_size("0");
- }
- // we can fairly easily predict the size of a formatted string here with lzcnt, which also
- // means we can write directly into the correct offsets of the output string.
- let printed_size = ((8 - v.leading_zeros() + 3) >> 2) as usize;
-
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + printed_size {
- panic!("InstructionTextSink::write_u8 would overflow output");
- }
- }
-
- let buf = unsafe { self.buf.as_mut_vec() };
- let new_len = buf.len() + printed_size;
-
- unsafe {
- buf.set_len(new_len);
- }
- let mut p = unsafe { buf.as_mut_ptr().offset(new_len as isize) };
-
- loop {
- let digit = v % 16;
- let c = c_to_hex(digit as u8);
- unsafe {
- p = p.offset(-1);
- p.write(c);
- }
- v = v / 16;
- if v == 0 {
- break;
- }
- }
-
- Ok(())
- }
- /// write a u16 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- #[inline(always)]
- fn write_u16(&mut self, mut v: u16) -> Result<(), core::fmt::Error> {
- if v == 0 {
- return self.write_fixed_size("0");
- }
-
- // we can fairly easily predict the size of a formatted string here with lzcnt, which also
- // means we can write directly into the correct offsets of the output string.
- let printed_size = ((16 - v.leading_zeros() + 3) >> 2) as usize;
-
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + printed_size {
- panic!("InstructionTextSink::write_u16 would overflow output");
- }
- }
-
- let buf = unsafe { self.buf.as_mut_vec() };
- let new_len = buf.len() + printed_size;
-
- unsafe {
- buf.set_len(new_len);
- }
- let mut p = unsafe { buf.as_mut_ptr().offset(new_len as isize) };
-
- loop {
- let digit = v % 16;
- let c = c_to_hex(digit as u8);
- unsafe {
- p = p.offset(-1);
- p.write(c);
- }
- v = v / 16;
- if v == 0 {
- break;
- }
- }
-
- Ok(())
- }
- /// write a u32 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- #[inline(always)]
- fn write_u32(&mut self, mut v: u32) -> Result<(), core::fmt::Error> {
- if v == 0 {
- return self.write_fixed_size("0");
- }
-
- // we can fairly easily predict the size of a formatted string here with lzcnt, which also
- // means we can write directly into the correct offsets of the output string.
- let printed_size = ((32 - v.leading_zeros() + 3) >> 2) as usize;
-
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + printed_size {
- panic!("InstructionTextSink::write_u32 would overflow output");
- }
- }
-
- let buf = unsafe { self.buf.as_mut_vec() };
- let new_len = buf.len() + printed_size;
-
- unsafe {
- buf.set_len(new_len);
- }
- let mut p = unsafe { buf.as_mut_ptr().offset(new_len as isize) };
-
- loop {
- let digit = v % 16;
- let c = c_to_hex(digit as u8);
- unsafe {
- p = p.offset(-1);
- p.write(c);
- }
- v = v / 16;
- if v == 0 {
- break;
- }
- }
-
- Ok(())
- }
- /// write a u64 to the output as a base-16 integer.
- ///
- /// this is provided for optimization opportunities when the formatted integer can be written
- /// directly to the sink (rather than formatted to an intermediate buffer and output as a
- /// followup step)
- #[inline(always)]
- fn write_u64(&mut self, mut v: u64) -> Result<(), core::fmt::Error> {
- if v == 0 {
- return self.write_fixed_size("0");
- }
-
- // we can fairly easily predict the size of a formatted string here with lzcnt, which also
- // means we can write directly into the correct offsets of the output string.
- let printed_size = ((64 - v.leading_zeros() + 3) >> 2) as usize;
-
- if cfg!(debug_assertions) {
- if self.buf.capacity() < self.buf.len() + printed_size {
- panic!("InstructionTextSink::write_u64 would overflow output");
- }
- }
-
- let buf = unsafe { self.buf.as_mut_vec() };
- let new_len = buf.len() + printed_size;
-
- unsafe {
- buf.set_len(new_len);
- }
- let mut p = unsafe { buf.as_mut_ptr().offset(new_len as isize) };
-
- loop {
- let digit = v % 16;
- let c = c_to_hex(digit as u8);
- unsafe {
- p = p.offset(-1);
- p.write(c);
- }
- v = v / 16;
- if v == 0 {
- break;
- }
- }
-
- Ok(())
- }
- fn span_start(&mut self, _ty: TokenType) {}
- fn span_end(&mut self, _ty: TokenType) {}
-}
generated by cgit v1.1 at 2024-07-01 12:05:34 +0000