From 347042c45ced56b37a665a2c4b042b7f7aae8e03 Mon Sep 17 00:00:00 2001 From: iximeow Date: Sat, 22 Jun 2024 00:25:01 -0700 Subject: extract reusable display bits into yaxpeax-arch, add a visitor fn to Operand comes with deleting the body of impl Colorize for Operand, because we can reuse the normal operand formatting code --- src/display.rs | 1076 -------------------------------------------------------- 1 file changed, 1076 deletions(-) (limited to 'src/display.rs') 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) {} -} -- cgit v1.1