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-rw-r--r--src/long_mode/display.rs1192
1 files changed, 100 insertions, 1092 deletions
diff --git a/src/long_mode/display.rs b/src/long_mode/display.rs
index ca5e580..d9799e1 100644
--- a/src/long_mode/display.rs
+++ b/src/long_mode/display.rs
@@ -4,10 +4,12 @@ use yaxpeax_arch::{Colorize, ShowContextual, NoColors, YaxColors};
use yaxpeax_arch::display::*;
use crate::safer_unchecked::GetSaferUnchecked as _;
-use crate::safer_unchecked::unreachable_kinda_unchecked;
use crate::MEM_SIZE_STRINGS;
use crate::long_mode::{RegSpec, Opcode, Operand, MergeMode, InstDecoder, Instruction, Segment, PrefixRex, OperandSpec};
+use crate::display::DisplaySink;
+use crate::display::TokenType;
+
impl fmt::Display for InstDecoder {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if self == &InstDecoder::default() {
@@ -363,1069 +365,6 @@ impl <T: fmt::Write, Y: YaxColors> Colorize<T, Y> for Operand {
}
}
-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)
- }
-}
-
-/// helper to format `amd64` instructions with highest throughupt and least configuration.
-///
-/// ### when to use this over `fmt::Display`?
-///
-/// `fmt::Display` is a fair choice in most cases. in some cases, `InstructionFormatter` may
-/// support formatting options that may be difficult to configure for a `Display` impl.
-/// additionally, `InstructionFormatter` may be able to specialize more effectively where
-/// `fmt::Display`, writing to a generic `fmt::Write`, may not.
-///
-/// if your use case for `yaxpeax-x86` involves being bounded on the speed of disassembling and
-/// formatting instructions, [`InstructionFormatter::format_inst`] has been measured as up to 11%
-/// faster than an equivalent `write!(buf, "{}", inst)`.
-///
-/// `InstructionFormatter` involves internal allocations; if your use case for `yaxpeax-x86`
-/// requires allocations never occurring, it is not an appropriate tool.
-///
-/// ### example
-///
-/// ```
-/// use yaxpeax_x86::long_mode::InstDecoder;
-/// use yaxpeax_x86::long_mode::InstructionFormatter;
-///
-/// let bytes = &[0x33, 0xc0];
-/// let inst = InstDecoder::default().decode_slice(bytes).expect("can decode");
-/// let mut formatter = InstructionFormatter::new();
-/// assert_eq!(
-/// formatter.format_inst(&inst).expect("can format"),
-/// "xor eax, eax"
-/// );
-///
-/// // or, getting the formatted instruction with `text_str`:
-/// assert_eq!(
-/// formatter.text_str(),
-/// "xor eax, eax"
-/// );
-/// ```
-pub struct InstructionFormatter {
- content: alloc::string::String,
-}
-
-impl InstructionFormatter {
- /// create an `InstructionFormatter` with default settings. `InstructionFormatter`'s default
- /// settings format instructions identically to their corresponding `fmt::Display`.
- pub fn new() -> Self {
- let mut buf = alloc::string::String::new();
- // TODO: move 512 out to a MAX_INSTRUCTION_LEN const and appropriate justification (and
- // fuzzing and ..)
- buf.reserve(512);
- Self {
- content: buf,
- }
- }
-
- /// format `inst` through this formatter, storing the formatted text in this formatter's
- /// internal buffer. returns a borrow of that same internal buffer for convenience.
- ///
- /// this clears and reuses an internal buffer; if an instruction had been previously formatted
- /// through this formatter, it will be overwritten.
- pub fn format_inst<'formatter>(&'formatter mut self, inst: &Instruction) -> Result<&'formatter str, fmt::Error> {
- let mut handle = self.write_handle();
-
- inst.write_to(&mut handle)?;
-
- Ok(self.text_str())
- }
-
- /// return a borrow of this formatter's buffer. if an instruction has been formatted, the
- /// returned `&str` contains that formatted instruction's text.
- pub fn text_str(&self) -> &str {
- self.content.as_str()
- }
-
- fn write_handle(&mut self) -> InstructionTextSink {
- self.content.clear();
- InstructionTextSink {
- buf: &mut self.content
- }
- }
-}
-
-/// this private struct is guaranteed to contain a string that is long enough to hold a
-/// fully-formatted x86 instruction.
-///
-/// this is wildly dangerous in general use, but because of the constrained lifecycle of
-/// `InstructionTextSink` in the context of `InstructionFormatter`, it's OK to use here. it is
-/// wildly dangerous because writing to this sink does not bounds check and assumes the contained
-/// `buf` is large enough for any input. as an example: if `buf` did not have enough space
-/// available from its current position, the `write_*` methods would write into whatever happens to
-/// be after `buf` in memory.
-///
-/// don't make this pub. if this is pub in docs, it's a bug.
-struct InstructionTextSink<'buf> {
- buf: &'buf mut alloc::string::String
-}
-
-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> {
- // 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> {
- 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> {
- // 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> {
- // 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> {
- // 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;
-
- 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;
-
- 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;
-
- 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;
-
- 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) {}
-}
-
struct ColorizingOperandVisitor<'a, T> {
f: &'a mut T,
}
@@ -4772,6 +3711,9 @@ pub struct InstructionDisplayer<'instr> {
*
* so write to some Write thing i guess. bite me. i really just want to
* stop thinking about how to support printing instructions...
+ *
+ * UPDATE: really wish i thought of DisplaySink back then, really wish this was bounded as T:
+ * DisplaySink.
*/
impl <'instr, T: fmt::Write, Y: YaxColors> Colorize<T, Y> for InstructionDisplayer<'instr> {
fn colorize(&self, colors: &Y, out: &mut T) -> fmt::Result {
@@ -4784,32 +3726,15 @@ impl <'instr, T: fmt::Write, Y: YaxColors> Colorize<T, Y> for InstructionDisplay
/// No per-operand context when contextualizing an instruction!
struct NoContext;
-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
- }
-}
-
impl Instruction {
#[cfg_attr(feature="profiling", inline(never))]
pub fn write_to<T: DisplaySink>(&self, out: &mut T) -> fmt::Result {
contextualize_intel(self, out)
-// self.display_with(DisplayStyle::Intel).contextualize(&NoColors, 0, Some(&NoContext), out)
}
}
#[cfg_attr(feature="profiling", inline(never))]
-fn contextualize_intel<T: DisplaySink>(instr: &Instruction, out: &mut T) -> fmt::Result {
+pub(crate) fn contextualize_intel<T: DisplaySink>(instr: &Instruction, out: &mut T) -> fmt::Result {
if instr.xacquire() {
out.write_fixed_size("xacquire ")?;
}
@@ -4951,7 +3876,7 @@ fn contextualize_intel<T: DisplaySink>(instr: &Instruction, out: &mut T) -> fmt:
Ok(())
}
-fn contextualize_c<T: fmt::Write>(instr: &Instruction, _address: u64, _context: Option<&NoContext>, out: &mut T) -> fmt::Result {
+pub(crate) fn contextualize_c<T: DisplaySink>(instr: &Instruction, out: &mut T) -> fmt::Result {
let mut brace_count = 0;
let mut prefixed = false;
@@ -5286,23 +4211,22 @@ fn contextualize_c<T: fmt::Write>(instr: &Instruction, _address: u64, _context:
}
impl <'instr, T: fmt::Write, Y: YaxColors> ShowContextual<u64, NoContext, T, Y> for InstructionDisplayer<'instr> {
- fn contextualize(&self, _colors: &Y, address: u64, context: Option<&NoContext>, out: &mut T) -> fmt::Result {
+ fn contextualize(&self, _colors: &Y, _address: u64, _context: Option<&NoContext>, out: &mut T) -> fmt::Result {
let InstructionDisplayer {
instr,
style,
} = self;
+ let mut out = crate::display::NoColorsSink {
+ out: out,
+ };
+
match style {
DisplayStyle::Intel => {
- let mut out = NoColorsSink {
- out,
- };
- let out = &mut out;
-
- contextualize_intel(instr, out)
+ contextualize_intel(instr, &mut out)
}
DisplayStyle::C => {
- contextualize_c(instr, address, context, out)
+ contextualize_c(instr, &mut out)
}
}
}
@@ -5311,7 +4235,7 @@ impl <'instr, T: fmt::Write, Y: YaxColors> ShowContextual<u64, NoContext, T, Y>
#[cfg(feature="std")]
impl <T: fmt::Write, Y: YaxColors> ShowContextual<u64, [Option<alloc::string::String>], T, Y> for Instruction {
fn contextualize(&self, colors: &Y, _address: u64, context: Option<&[Option<alloc::string::String>]>, out: &mut T) -> fmt::Result {
- let mut out = NoColorsSink {
+ let mut out = crate::display::NoColorsSink {
out,
};
let out = &mut out;
@@ -5528,3 +4452,87 @@ impl<'a, F: DisplaySink> crate::long_mode::OperandVisitor for RelativeBranchPrin
}
}
+/// helper to format `amd64` instructions with highest throughput and least configuration. this is
+/// functionally a buffer for one x86 instruction's text.
+///
+/// ### when to use this over `fmt::Display`?
+///
+/// `fmt::Display` is a fair choice in most cases. in some cases, `InstructionTextBuffer` may
+/// support formatting options that may be difficult to configure for a `Display` impl.
+/// additionally, `InstructionTextBuffer` may be able to specialize more effectively where
+/// `fmt::Display`, writing to a generic `fmt::Write`, may not.
+///
+/// if your use case for `yaxpeax-x86` involves being bounded on the speed of disassembling and
+/// formatting instructions, [`InstructionTextBuffer::format_inst`] has been measured as up to 11%
+/// faster than an equivalent `write!(buf, "{}", inst)`.
+///
+/// `InstructionTextBuffer` involves internal allocations; if your use case for `yaxpeax-x86`
+/// requires allocations never occurring, it is not an appropriate tool.
+///
+/// ### example
+///
+/// ```
+/// use yaxpeax_x86::long_mode::InstDecoder;
+/// use yaxpeax_x86::long_mode::InstructionTextBuffer;
+///
+/// let bytes = &[0x33, 0xc0];
+/// let inst = InstDecoder::default().decode_slice(bytes).expect("can decode");
+/// let mut text_buf = InstructionTextBuffer::new();
+/// assert_eq!(
+/// text_buf.format_inst(&inst).expect("can format"),
+/// "xor eax, eax"
+/// );
+///
+/// // or, getting the formatted instruction with `text_str`:
+/// assert_eq!(
+/// text_buf.text_str(),
+/// "xor eax, eax"
+/// );
+/// ```
+pub struct InstructionTextBuffer {
+ content: alloc::string::String,
+}
+
+impl InstructionTextBuffer {
+ /// create an `InstructionTextBuffer` with default settings. `InstructionTextBuffer`'s default
+ /// settings format instructions identically to their corresponding `fmt::Display`.
+ pub fn new() -> Self {
+ let mut buf = alloc::string::String::new();
+ // TODO: move 512 out to a MAX_INSTRUCTION_LEN const and appropriate justification (and
+ // fuzzing and ..)
+ buf.reserve(512);
+ Self {
+ content: buf,
+ }
+ }
+
+ /// format `inst` into this buffer. returns a borrow of that same internal buffer for convenience.
+ ///
+ /// this clears and reuses an internal buffer; if an instruction had been previously formatted
+ /// through this buffer, it will be overwritten.
+ pub fn format_inst<'buf, 'instr>(&'buf mut self, display: &InstructionDisplayer<'instr>) -> Result<&'buf str, fmt::Error> {
+ let mut handle = self.write_handle();
+
+ match display.style {
+ DisplayStyle::Intel => {
+ contextualize_intel(&display.instr, &mut handle)?;
+ }
+ DisplayStyle::C => {
+ contextualize_c(&display.instr, &mut handle)?;
+ }
+ }
+
+ Ok(self.text_str())
+ }
+
+ /// return a borrow of the internal buffer. if an instruction has been formatted, the
+ /// returned `&str` contains that instruction's buffered text.
+ pub fn text_str(&self) -> &str {
+ self.content.as_str()
+ }
+
+ fn write_handle(&mut self) -> crate::display::InstructionTextSink {
+ self.content.clear();
+ crate::display::InstructionTextSink::new(&mut self.content)
+ }
+}
generated by cgit v1.1 at 2024-11-01 15:28:50 +0000