Rollup merge of #110766 - m-ou-se:fmt-rt, r=jyn514

More core::fmt::rt cleanup.

- Removes the `V1` suffix from the `Argument` and `Flag` types.

- Moves more of the format_args lang items into the `core::fmt::rt` module. (The only remaining lang item in `core::fmt` is `Arguments` itself, which is a public type.)

Part of https://github.com/rust-lang/rust/issues/99012

Follow-up to https://github.com/rust-lang/rust/pull/110616
This commit is contained in:
Matthias Krüger 2023-04-28 07:34:02 +02:00 committed by GitHub
commit cf911ac757
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GPG Key ID: 4AEE18F83AFDEB23
12 changed files with 312 additions and 311 deletions

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@ -186,7 +186,7 @@ enum ArgumentType {
/// Generates:
///
/// ```text
/// <core::fmt::ArgumentV1>::new_…(arg)
/// <core::fmt::Argument>::new_…(arg)
/// ```
fn make_argument<'hir>(
ctx: &mut LoweringContext<'_, 'hir>,
@ -327,7 +327,7 @@ fn make_format_spec<'hir>(
None => sym::Unknown,
},
);
// This needs to match `FlagV1` in library/core/src/fmt/mod.rs.
// This needs to match `Flag` in library/core/src/fmt/rt.rs.
let flags: u32 = ((sign == Some(FormatSign::Plus)) as u32)
| ((sign == Some(FormatSign::Minus)) as u32) << 1
| (alternate as u32) << 2
@ -438,7 +438,7 @@ fn expand_format_args<'hir>(
// If the args array contains exactly all the original arguments once,
// in order, we can use a simple array instead of a `match` construction.
// However, if there's a yield point in any argument except the first one,
// we don't do this, because an ArgumentV1 cannot be kept across yield points.
// we don't do this, because an Argument cannot be kept across yield points.
//
// This is an optimization, speeding up compilation about 1-2% in some cases.
// See https://github.com/rust-lang/rust/pull/106770#issuecomment-1380790609
@ -449,9 +449,9 @@ fn expand_format_args<'hir>(
let args = if use_simple_array {
// Generate:
// &[
// <core::fmt::ArgumentV1>::new_display(&arg0),
// <core::fmt::ArgumentV1>::new_lower_hex(&arg1),
// <core::fmt::ArgumentV1>::new_debug(&arg2),
// <core::fmt::Argument>::new_display(&arg0),
// <core::fmt::Argument>::new_lower_hex(&arg1),
// <core::fmt::Argument>::new_debug(&arg2),
// …
// ]
let elements: Vec<_> = arguments
@ -477,9 +477,9 @@ fn expand_format_args<'hir>(
// Generate:
// &match (&arg0, &arg1, &…) {
// args => [
// <core::fmt::ArgumentV1>::new_display(args.0),
// <core::fmt::ArgumentV1>::new_lower_hex(args.1),
// <core::fmt::ArgumentV1>::new_debug(args.0),
// <core::fmt::Argument>::new_display(args.0),
// <core::fmt::Argument>::new_lower_hex(args.1),
// <core::fmt::Argument>::new_debug(args.0),
// …
// ]
// }

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@ -296,7 +296,7 @@ macro_rules! error {
diag_trait(&mut err, self_ty, tcx.require_lang_item(LangItem::Deref, Some(span)));
err
}
_ if tcx.opt_parent(callee) == tcx.get_diagnostic_item(sym::ArgumentV1Methods) => ccx
_ if tcx.opt_parent(callee) == tcx.get_diagnostic_item(sym::ArgumentMethods) => ccx
.tcx
.sess
.create_err(errors::NonConstFmtMacroCall { span, kind: ccx.const_kind() }),

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@ -129,8 +129,7 @@
Any,
Arc,
Argument,
ArgumentV1,
ArgumentV1Methods,
ArgumentMethods,
Arguments,
AsMut,
AsRef,

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@ -251,223 +251,6 @@ pub fn new(buf: &'a mut (dyn Write + 'a)) -> Formatter<'a> {
}
}
// NB. Argument is essentially an optimized partially applied formatting function,
// equivalent to `exists T.(&T, fn(&T, &mut Formatter<'_>) -> Result`.
extern "C" {
type Opaque;
}
/// This struct represents the generic "argument" which is taken by the Xprintf
/// family of functions. It contains a function to format the given value. At
/// compile time it is ensured that the function and the value have the correct
/// types, and then this struct is used to canonicalize arguments to one type.
#[lang = "format_argument"]
#[derive(Copy, Clone)]
#[allow(missing_debug_implementations)]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
#[doc(hidden)]
pub struct ArgumentV1<'a> {
value: &'a Opaque,
formatter: fn(&Opaque, &mut Formatter<'_>) -> Result,
}
/// This struct represents the unsafety of constructing an `Arguments`.
/// It exists, rather than an unsafe function, in order to simplify the expansion
/// of `format_args!(..)` and reduce the scope of the `unsafe` block.
#[lang = "format_unsafe_arg"]
#[allow(missing_debug_implementations)]
#[doc(hidden)]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
pub struct UnsafeArg {
_private: (),
}
impl UnsafeArg {
/// See documentation where `UnsafeArg` is required to know when it is safe to
/// create and use `UnsafeArg`.
#[doc(hidden)]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
#[inline(always)]
pub unsafe fn new() -> Self {
Self { _private: () }
}
}
// This guarantees a single stable value for the function pointer associated with
// indices/counts in the formatting infrastructure.
//
// Note that a function defined as such would not be correct as functions are
// always tagged unnamed_addr with the current lowering to LLVM IR, so their
// address is not considered important to LLVM and as such the as_usize cast
// could have been miscompiled. In practice, we never call as_usize on non-usize
// containing data (as a matter of static generation of the formatting
// arguments), so this is merely an additional check.
//
// We primarily want to ensure that the function pointer at `USIZE_MARKER` has
// an address corresponding *only* to functions that also take `&usize` as their
// first argument. The read_volatile here ensures that we can safely ready out a
// usize from the passed reference and that this address does not point at a
// non-usize taking function.
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
static USIZE_MARKER: fn(&usize, &mut Formatter<'_>) -> Result = |ptr, _| {
// SAFETY: ptr is a reference
let _v: usize = unsafe { crate::ptr::read_volatile(ptr) };
loop {}
};
macro_rules! arg_new {
($f: ident, $t: ident) => {
#[doc(hidden)]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
#[inline]
pub fn $f<'b, T: $t>(x: &'b T) -> ArgumentV1<'_> {
Self::new(x, $t::fmt)
}
};
}
#[rustc_diagnostic_item = "ArgumentV1Methods"]
impl<'a> ArgumentV1<'a> {
#[doc(hidden)]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
#[inline]
pub fn new<'b, T>(x: &'b T, f: fn(&T, &mut Formatter<'_>) -> Result) -> ArgumentV1<'b> {
// SAFETY: `mem::transmute(x)` is safe because
// 1. `&'b T` keeps the lifetime it originated with `'b`
// (so as to not have an unbounded lifetime)
// 2. `&'b T` and `&'b Opaque` have the same memory layout
// (when `T` is `Sized`, as it is here)
// `mem::transmute(f)` is safe since `fn(&T, &mut Formatter<'_>) -> Result`
// and `fn(&Opaque, &mut Formatter<'_>) -> Result` have the same ABI
// (as long as `T` is `Sized`)
unsafe { ArgumentV1 { formatter: mem::transmute(f), value: mem::transmute(x) } }
}
arg_new!(new_display, Display);
arg_new!(new_debug, Debug);
arg_new!(new_octal, Octal);
arg_new!(new_lower_hex, LowerHex);
arg_new!(new_upper_hex, UpperHex);
arg_new!(new_pointer, Pointer);
arg_new!(new_binary, Binary);
arg_new!(new_lower_exp, LowerExp);
arg_new!(new_upper_exp, UpperExp);
#[doc(hidden)]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
pub fn from_usize(x: &usize) -> ArgumentV1<'_> {
ArgumentV1::new(x, USIZE_MARKER)
}
fn as_usize(&self) -> Option<usize> {
// We are type punning a bit here: USIZE_MARKER only takes an &usize but
// formatter takes an &Opaque. Rust understandably doesn't think we should compare
// the function pointers if they don't have the same signature, so we cast to
// usizes to tell it that we just want to compare addresses.
if self.formatter as usize == USIZE_MARKER as usize {
// SAFETY: The `formatter` field is only set to USIZE_MARKER if
// the value is a usize, so this is safe
Some(unsafe { *(self.value as *const _ as *const usize) })
} else {
None
}
}
}
// flags available in the v1 format of format_args
#[derive(Copy, Clone)]
enum FlagV1 {
SignPlus,
SignMinus,
Alternate,
SignAwareZeroPad,
DebugLowerHex,
DebugUpperHex,
}
impl<'a> Arguments<'a> {
#[doc(hidden)]
#[inline]
#[unstable(feature = "fmt_internals", issue = "none")]
#[rustc_const_unstable(feature = "const_fmt_arguments_new", issue = "none")]
pub const fn new_const(pieces: &'a [&'static str]) -> Self {
if pieces.len() > 1 {
panic!("invalid args");
}
Arguments { pieces, fmt: None, args: &[] }
}
/// When using the format_args!() macro, this function is used to generate the
/// Arguments structure.
#[cfg(not(bootstrap))]
#[doc(hidden)]
#[inline]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
pub fn new_v1(pieces: &'a [&'static str], args: &'a [ArgumentV1<'a>]) -> Arguments<'a> {
if pieces.len() < args.len() || pieces.len() > args.len() + 1 {
panic!("invalid args");
}
Arguments { pieces, fmt: None, args }
}
#[cfg(bootstrap)]
#[doc(hidden)]
#[inline]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
#[rustc_const_unstable(feature = "const_fmt_arguments_new", issue = "none")]
pub const fn new_v1(pieces: &'a [&'static str], args: &'a [ArgumentV1<'a>]) -> Arguments<'a> {
if pieces.len() < args.len() || pieces.len() > args.len() + 1 {
panic!("invalid args");
}
Arguments { pieces, fmt: None, args }
}
/// This function is used to specify nonstandard formatting parameters.
///
/// An `UnsafeArg` is required because the following invariants must be held
/// in order for this function to be safe:
/// 1. The `pieces` slice must be at least as long as `fmt`.
/// 2. Every `rt::Placeholder::position` value within `fmt` must be a valid index of `args`.
/// 3. Every `rt::Count::Param` within `fmt` must contain a valid index of `args`.
#[doc(hidden)]
#[inline]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
pub fn new_v1_formatted(
pieces: &'a [&'static str],
args: &'a [ArgumentV1<'a>],
fmt: &'a [rt::Placeholder],
_unsafe_arg: UnsafeArg,
) -> Arguments<'a> {
Arguments { pieces, fmt: Some(fmt), args }
}
/// Estimates the length of the formatted text.
///
/// This is intended to be used for setting initial `String` capacity
/// when using `format!`. Note: this is neither the lower nor upper bound.
#[doc(hidden)]
#[inline]
#[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
pub fn estimated_capacity(&self) -> usize {
let pieces_length: usize = self.pieces.iter().map(|x| x.len()).sum();
if self.args.is_empty() {
pieces_length
} else if !self.pieces.is_empty() && self.pieces[0].is_empty() && pieces_length < 16 {
// If the format string starts with an argument,
// don't preallocate anything, unless length
// of pieces is significant.
0
} else {
// There are some arguments, so any additional push
// will reallocate the string. To avoid that,
// we're "pre-doubling" the capacity here.
pieces_length.checked_mul(2).unwrap_or(0)
}
}
}
/// This structure represents a safely precompiled version of a format string
/// and its arguments. This cannot be generated at runtime because it cannot
/// safely be done, so no constructors are given and the fields are private
@ -502,7 +285,82 @@ pub struct Arguments<'a> {
// Dynamic arguments for interpolation, to be interleaved with string
// pieces. (Every argument is preceded by a string piece.)
args: &'a [ArgumentV1<'a>],
args: &'a [rt::Argument<'a>],
}
/// Used by the format_args!() macro to create a fmt::Arguments object.
#[doc(hidden)]
#[unstable(feature = "fmt_internals", issue = "none")]
impl<'a> Arguments<'a> {
#[inline]
#[rustc_const_unstable(feature = "const_fmt_arguments_new", issue = "none")]
pub const fn new_const(pieces: &'a [&'static str]) -> Self {
if pieces.len() > 1 {
panic!("invalid args");
}
Arguments { pieces, fmt: None, args: &[] }
}
/// When using the format_args!() macro, this function is used to generate the
/// Arguments structure.
#[cfg(not(bootstrap))]
#[inline]
pub fn new_v1(pieces: &'a [&'static str], args: &'a [rt::Argument<'a>]) -> Arguments<'a> {
if pieces.len() < args.len() || pieces.len() > args.len() + 1 {
panic!("invalid args");
}
Arguments { pieces, fmt: None, args }
}
#[cfg(bootstrap)]
#[inline]
#[rustc_const_unstable(feature = "const_fmt_arguments_new", issue = "none")]
pub const fn new_v1(pieces: &'a [&'static str], args: &'a [rt::Argument<'a>]) -> Arguments<'a> {
if pieces.len() < args.len() || pieces.len() > args.len() + 1 {
panic!("invalid args");
}
Arguments { pieces, fmt: None, args }
}
/// This function is used to specify nonstandard formatting parameters.
///
/// An `rt::UnsafeArg` is required because the following invariants must be held
/// in order for this function to be safe:
/// 1. The `pieces` slice must be at least as long as `fmt`.
/// 2. Every `rt::Placeholder::position` value within `fmt` must be a valid index of `args`.
/// 3. Every `rt::Count::Param` within `fmt` must contain a valid index of `args`.
#[inline]
pub fn new_v1_formatted(
pieces: &'a [&'static str],
args: &'a [rt::Argument<'a>],
fmt: &'a [rt::Placeholder],
_unsafe_arg: rt::UnsafeArg,
) -> Arguments<'a> {
Arguments { pieces, fmt: Some(fmt), args }
}
/// Estimates the length of the formatted text.
///
/// This is intended to be used for setting initial `String` capacity
/// when using `format!`. Note: this is neither the lower nor upper bound.
#[inline]
pub fn estimated_capacity(&self) -> usize {
let pieces_length: usize = self.pieces.iter().map(|x| x.len()).sum();
if self.args.is_empty() {
pieces_length
} else if !self.pieces.is_empty() && self.pieces[0].is_empty() && pieces_length < 16 {
// If the format string starts with an argument,
// don't preallocate anything, unless length
// of pieces is significant.
0
} else {
// There are some arguments, so any additional push
// will reallocate the string. To avoid that,
// we're "pre-doubling" the capacity here.
pieces_length.checked_mul(2).unwrap_or(0)
}
}
}
impl<'a> Arguments<'a> {
@ -1244,7 +1102,7 @@ pub fn write(output: &mut dyn Write, args: Arguments<'_>) -> Result {
if !piece.is_empty() {
formatter.buf.write_str(*piece)?;
}
(arg.formatter)(arg.value, &mut formatter)?;
arg.fmt(&mut formatter)?;
idx += 1;
}
}
@ -1274,7 +1132,7 @@ pub fn write(output: &mut dyn Write, args: Arguments<'_>) -> Result {
Ok(())
}
unsafe fn run(fmt: &mut Formatter<'_>, arg: &rt::Placeholder, args: &[ArgumentV1<'_>]) -> Result {
unsafe fn run(fmt: &mut Formatter<'_>, arg: &rt::Placeholder, args: &[rt::Argument<'_>]) -> Result {
fmt.fill = arg.fill;
fmt.align = arg.align;
fmt.flags = arg.flags;
@ -1292,10 +1150,10 @@ unsafe fn run(fmt: &mut Formatter<'_>, arg: &rt::Placeholder, args: &[ArgumentV1
let value = unsafe { args.get_unchecked(arg.position) };
// Then actually do some printing
(value.formatter)(value.value, fmt)
value.fmt(fmt)
}
unsafe fn getcount(args: &[ArgumentV1<'_>], cnt: &rt::Count) -> Option<usize> {
unsafe fn getcount(args: &[rt::Argument<'_>], cnt: &rt::Count) -> Option<usize> {
match *cnt {
rt::Count::Is(n) => Some(n),
rt::Count::Implied => None,
@ -1878,7 +1736,7 @@ pub fn precision(&self) -> Option<usize> {
#[must_use]
#[stable(feature = "fmt_flags", since = "1.5.0")]
pub fn sign_plus(&self) -> bool {
self.flags & (1 << FlagV1::SignPlus as u32) != 0
self.flags & (1 << rt::Flag::SignPlus as u32) != 0
}
/// Determines if the `-` flag was specified.
@ -1907,7 +1765,7 @@ pub fn sign_plus(&self) -> bool {
#[must_use]
#[stable(feature = "fmt_flags", since = "1.5.0")]
pub fn sign_minus(&self) -> bool {
self.flags & (1 << FlagV1::SignMinus as u32) != 0
self.flags & (1 << rt::Flag::SignMinus as u32) != 0
}
/// Determines if the `#` flag was specified.
@ -1935,7 +1793,7 @@ pub fn sign_minus(&self) -> bool {
#[must_use]
#[stable(feature = "fmt_flags", since = "1.5.0")]
pub fn alternate(&self) -> bool {
self.flags & (1 << FlagV1::Alternate as u32) != 0
self.flags & (1 << rt::Flag::Alternate as u32) != 0
}
/// Determines if the `0` flag was specified.
@ -1961,17 +1819,17 @@ pub fn alternate(&self) -> bool {
#[must_use]
#[stable(feature = "fmt_flags", since = "1.5.0")]
pub fn sign_aware_zero_pad(&self) -> bool {
self.flags & (1 << FlagV1::SignAwareZeroPad as u32) != 0
self.flags & (1 << rt::Flag::SignAwareZeroPad as u32) != 0
}
// FIXME: Decide what public API we want for these two flags.
// https://github.com/rust-lang/rust/issues/48584
fn debug_lower_hex(&self) -> bool {
self.flags & (1 << FlagV1::DebugLowerHex as u32) != 0
self.flags & (1 << rt::Flag::DebugLowerHex as u32) != 0
}
fn debug_upper_hex(&self) -> bool {
self.flags & (1 << FlagV1::DebugUpperHex as u32) != 0
self.flags & (1 << rt::Flag::DebugUpperHex as u32) != 0
}
/// Creates a [`DebugStruct`] builder designed to assist with creation of
@ -2531,13 +2389,13 @@ pub(crate) fn pointer_fmt_inner(ptr_addr: usize, f: &mut Formatter<'_>) -> Resul
// or not to zero extend, and then unconditionally set it to get the
// prefix.
if f.alternate() {
f.flags |= 1 << (FlagV1::SignAwareZeroPad as u32);
f.flags |= 1 << (rt::Flag::SignAwareZeroPad as u32);
if f.width.is_none() {
f.width = Some((usize::BITS / 4) as usize + 2);
}
}
f.flags |= 1 << (FlagV1::Alternate as u32);
f.flags |= 1 << (rt::Flag::Alternate as u32);
let ret = LowerHex::fmt(&ptr_addr, f);

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@ -3,6 +3,8 @@
//! These are the lang items used by format_args!().
use super::*;
#[lang = "format_placeholder"]
#[derive(Copy, Clone)]
pub struct Placeholder {
@ -28,21 +30,17 @@ pub const fn new(
}
}
/// Possible alignments that can be requested as part of a formatting directive.
#[lang = "format_alignment"]
#[derive(Copy, Clone, PartialEq, Eq)]
pub enum Alignment {
/// Indication that contents should be left-aligned.
Left,
/// Indication that contents should be right-aligned.
Right,
/// Indication that contents should be center-aligned.
Center,
/// No alignment was requested.
Unknown,
}
/// Used by [width](https://doc.rust-lang.org/std/fmt/#width) and [precision](https://doc.rust-lang.org/std/fmt/#precision) specifiers.
/// Used by [width](https://doc.rust-lang.org/std/fmt/#width)
/// and [precision](https://doc.rust-lang.org/std/fmt/#precision) specifiers.
#[lang = "format_count"]
#[derive(Copy, Clone)]
pub enum Count {
@ -53,3 +51,147 @@ pub enum Count {
/// Not specified
Implied,
}
// This needs to match the order of flags in compiler/rustc_ast_lowering/src/format.rs.
#[derive(Copy, Clone)]
pub(super) enum Flag {
SignPlus,
SignMinus,
Alternate,
SignAwareZeroPad,
DebugLowerHex,
DebugUpperHex,
}
/// This struct represents the generic "argument" which is taken by format_args!().
/// It contains a function to format the given value. At compile time it is ensured that the
/// function and the value have the correct types, and then this struct is used to canonicalize
/// arguments to one type.
///
/// Argument is essentially an optimized partially applied formatting function,
/// equivalent to `exists T.(&T, fn(&T, &mut Formatter<'_>) -> Result`.
#[lang = "format_argument"]
#[derive(Copy, Clone)]
pub struct Argument<'a> {
value: &'a Opaque,
formatter: fn(&Opaque, &mut Formatter<'_>) -> Result,
}
#[rustc_diagnostic_item = "ArgumentMethods"]
impl<'a> Argument<'a> {
#[inline(always)]
fn new<'b, T>(x: &'b T, f: fn(&T, &mut Formatter<'_>) -> Result) -> Argument<'b> {
// SAFETY: `mem::transmute(x)` is safe because
// 1. `&'b T` keeps the lifetime it originated with `'b`
// (so as to not have an unbounded lifetime)
// 2. `&'b T` and `&'b Opaque` have the same memory layout
// (when `T` is `Sized`, as it is here)
// `mem::transmute(f)` is safe since `fn(&T, &mut Formatter<'_>) -> Result`
// and `fn(&Opaque, &mut Formatter<'_>) -> Result` have the same ABI
// (as long as `T` is `Sized`)
unsafe { Argument { formatter: mem::transmute(f), value: mem::transmute(x) } }
}
#[inline(always)]
pub fn new_display<'b, T: Display>(x: &'b T) -> Argument<'_> {
Self::new(x, Display::fmt)
}
#[inline(always)]
pub fn new_debug<'b, T: Debug>(x: &'b T) -> Argument<'_> {
Self::new(x, Debug::fmt)
}
#[inline(always)]
pub fn new_octal<'b, T: Octal>(x: &'b T) -> Argument<'_> {
Self::new(x, Octal::fmt)
}
#[inline(always)]
pub fn new_lower_hex<'b, T: LowerHex>(x: &'b T) -> Argument<'_> {
Self::new(x, LowerHex::fmt)
}
#[inline(always)]
pub fn new_upper_hex<'b, T: UpperHex>(x: &'b T) -> Argument<'_> {
Self::new(x, UpperHex::fmt)
}
#[inline(always)]
pub fn new_pointer<'b, T: Pointer>(x: &'b T) -> Argument<'_> {
Self::new(x, Pointer::fmt)
}
#[inline(always)]
pub fn new_binary<'b, T: Binary>(x: &'b T) -> Argument<'_> {
Self::new(x, Binary::fmt)
}
#[inline(always)]
pub fn new_lower_exp<'b, T: LowerExp>(x: &'b T) -> Argument<'_> {
Self::new(x, LowerExp::fmt)
}
#[inline(always)]
pub fn new_upper_exp<'b, T: UpperExp>(x: &'b T) -> Argument<'_> {
Self::new(x, UpperExp::fmt)
}
#[inline(always)]
pub fn from_usize(x: &usize) -> Argument<'_> {
Self::new(x, USIZE_MARKER)
}
#[inline(always)]
pub(super) fn fmt(&self, f: &mut Formatter<'_>) -> Result {
(self.formatter)(self.value, f)
}
#[inline(always)]
pub(super) fn as_usize(&self) -> Option<usize> {
// We are type punning a bit here: USIZE_MARKER only takes an &usize but
// formatter takes an &Opaque. Rust understandably doesn't think we should compare
// the function pointers if they don't have the same signature, so we cast to
// usizes to tell it that we just want to compare addresses.
if self.formatter as usize == USIZE_MARKER as usize {
// SAFETY: The `formatter` field is only set to USIZE_MARKER if
// the value is a usize, so this is safe
Some(unsafe { *(self.value as *const _ as *const usize) })
} else {
None
}
}
}
/// This struct represents the unsafety of constructing an `Arguments`.
/// It exists, rather than an unsafe function, in order to simplify the expansion
/// of `format_args!(..)` and reduce the scope of the `unsafe` block.
#[lang = "format_unsafe_arg"]
pub struct UnsafeArg {
_private: (),
}
impl UnsafeArg {
/// See documentation where `UnsafeArg` is required to know when it is safe to
/// create and use `UnsafeArg`.
#[inline(always)]
pub unsafe fn new() -> Self {
Self { _private: () }
}
}
extern "C" {
type Opaque;
}
// This guarantees a single stable value for the function pointer associated with
// indices/counts in the formatting infrastructure.
//
// Note that a function defined as such would not be correct as functions are
// always tagged unnamed_addr with the current lowering to LLVM IR, so their
// address is not considered important to LLVM and as such the as_usize cast
// could have been miscompiled. In practice, we never call as_usize on non-usize
// containing data (as a matter of static generation of the formatting
// arguments), so this is merely an additional check.
//
// We primarily want to ensure that the function pointer at `USIZE_MARKER` has
// an address corresponding *only* to functions that also take `&usize` as their
// first argument. The read_volatile here ensures that we can safely ready out a
// usize from the passed reference and that this address does not point at a
// non-usize taking function.
static USIZE_MARKER: fn(&usize, &mut Formatter<'_>) -> Result = |ptr, _| {
// SAFETY: ptr is a reference
let _v: usize = unsafe { crate::ptr::read_volatile(ptr) };
loop {}
};

View File

@ -12,57 +12,59 @@ stack backtrace:
at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
4: <std::sys_common::backtrace::_print::DisplayBacktrace as std::fmt::Display>::fmt
at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
5: std::fmt::write
5: core::fmt::rt::Argument::fmt
at RUSTLIB/core/src/fmt/rt.rs:LL:CC
6: std::fmt::write
at RUSTLIB/core/src/fmt/mod.rs:LL:CC
6: <std::sys::PLATFORM::stdio::Stderr as std::io::Write>::write_fmt
7: <std::sys::PLATFORM::stdio::Stderr as std::io::Write>::write_fmt
at RUSTLIB/std/src/io/mod.rs:LL:CC
7: std::sys_common::backtrace::_print
8: std::sys_common::backtrace::_print
at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
8: std::sys_common::backtrace::print
9: std::sys_common::backtrace::print
at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
9: std::panicking::default_hook::{closure#1}
10: std::panicking::default_hook::{closure#1}
at RUSTLIB/std/src/panicking.rs:LL:CC
10: std::panicking::default_hook
11: std::panicking::default_hook
at RUSTLIB/std/src/panicking.rs:LL:CC
11: std::panicking::rust_panic_with_hook
12: std::panicking::rust_panic_with_hook
at RUSTLIB/std/src/panicking.rs:LL:CC
12: std::rt::begin_panic::{closure#0}
13: std::rt::begin_panic::{closure#0}
at RUSTLIB/std/src/panicking.rs:LL:CC
13: std::sys_common::backtrace::__rust_end_short_backtrace
14: std::sys_common::backtrace::__rust_end_short_backtrace
at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
14: std::rt::begin_panic
15: std::rt::begin_panic
at RUSTLIB/std/src/panicking.rs:LL:CC
15: <Foo as std::ops::Drop>::drop
16: <Foo as std::ops::Drop>::drop
at $DIR/double_panic.rs:LL:CC
16: std::ptr::drop_in_place - shim(Some(Foo))
17: std::ptr::drop_in_place - shim(Some(Foo))
at RUSTLIB/core/src/ptr/mod.rs:LL:CC
17: main
18: main
at $DIR/double_panic.rs:LL:CC
18: <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
19: <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
at RUSTLIB/core/src/ops/function.rs:LL:CC
19: std::sys_common::backtrace::__rust_begin_short_backtrace
20: std::sys_common::backtrace::__rust_begin_short_backtrace
at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
20: std::rt::lang_start::{closure#0}
21: std::rt::lang_start::{closure#0}
at RUSTLIB/std/src/rt.rs:LL:CC
21: std::ops::function::impls::call_once
22: std::ops::function::impls::call_once
at RUSTLIB/core/src/ops/function.rs:LL:CC
22: std::panicking::r#try::do_call
23: std::panicking::r#try::do_call
at RUSTLIB/std/src/panicking.rs:LL:CC
23: std::panicking::r#try
24: std::panicking::r#try
at RUSTLIB/std/src/panicking.rs:LL:CC
24: std::panic::catch_unwind
25: std::panic::catch_unwind
at RUSTLIB/std/src/panic.rs:LL:CC
25: std::rt::lang_start_internal::{closure#2}
26: std::rt::lang_start_internal::{closure#2}
at RUSTLIB/std/src/rt.rs:LL:CC
26: std::panicking::r#try::do_call
27: std::panicking::r#try::do_call
at RUSTLIB/std/src/panicking.rs:LL:CC
27: std::panicking::r#try
28: std::panicking::r#try
at RUSTLIB/std/src/panicking.rs:LL:CC
28: std::panic::catch_unwind
29: std::panic::catch_unwind
at RUSTLIB/std/src/panic.rs:LL:CC
29: std::rt::lang_start_internal
30: std::rt::lang_start_internal
at RUSTLIB/std/src/rt.rs:LL:CC
30: std::rt::lang_start
31: std::rt::lang_start
at RUSTLIB/std/src/rt.rs:LL:CC
thread panicked while panicking. aborting.
error: abnormal termination: the program aborted execution

View File

@ -201,7 +201,7 @@ macro_rules! format_args {
}
fn main() {
$crate::fmt::Arguments::new_v1(&[], &[$crate::fmt::ArgumentV1::new(&(arg1(a, b, c)), $crate::fmt::Display::fmt), $crate::fmt::ArgumentV1::new(&(arg2), $crate::fmt::Display::fmt), ]);
$crate::fmt::Arguments::new_v1(&[], &[$crate::fmt::Argument::new(&(arg1(a, b, c)), $crate::fmt::Display::fmt), $crate::fmt::Argument::new(&(arg2), $crate::fmt::Display::fmt), ]);
}
"#]],
);
@ -229,7 +229,7 @@ macro_rules! format_args {
}
fn main() {
$crate::fmt::Arguments::new_v1(&[], &[$crate::fmt::ArgumentV1::new(&(a::<A, B>()), $crate::fmt::Display::fmt), $crate::fmt::ArgumentV1::new(&(b), $crate::fmt::Display::fmt), ]);
$crate::fmt::Arguments::new_v1(&[], &[$crate::fmt::Argument::new(&(a::<A, B>()), $crate::fmt::Display::fmt), $crate::fmt::Argument::new(&(b), $crate::fmt::Display::fmt), ]);
}
"#]],
);
@ -260,7 +260,7 @@ macro_rules! format_args {
fn main() {
let _ =
/* parse error: expected field name or number */
$crate::fmt::Arguments::new_v1(&[], &[$crate::fmt::ArgumentV1::new(&(a.), $crate::fmt::Display::fmt), ]);
$crate::fmt::Arguments::new_v1(&[], &[$crate::fmt::Argument::new(&(a.), $crate::fmt::Display::fmt), ]);
}
"#]],
);

View File

@ -241,8 +241,8 @@ fn format_args_expand(
// We expand `format_args!("", a1, a2)` to
// ```
// $crate::fmt::Arguments::new_v1(&[], &[
// $crate::fmt::ArgumentV1::new(&arg1,$crate::fmt::Display::fmt),
// $crate::fmt::ArgumentV1::new(&arg2,$crate::fmt::Display::fmt),
// $crate::fmt::Argument::new(&arg1,$crate::fmt::Display::fmt),
// $crate::fmt::Argument::new(&arg2,$crate::fmt::Display::fmt),
// ])
// ```,
// which is still not really correct, but close enough for now
@ -267,7 +267,7 @@ fn format_args_expand(
}
let _format_string = args.remove(0);
let arg_tts = args.into_iter().flat_map(|arg| {
quote! { #DOLLAR_CRATE::fmt::ArgumentV1::new(&(#arg), #DOLLAR_CRATE::fmt::Display::fmt), }
quote! { #DOLLAR_CRATE::fmt::Argument::new(&(#arg), #DOLLAR_CRATE::fmt::Display::fmt), }
}.token_trees);
let expanded = quote! {
#DOLLAR_CRATE::fmt::Arguments::new_v1(&[], &[##arg_tts])

View File

@ -15,14 +15,14 @@
let mut _13: &[&str; 3]; // in scope 0 at $DIR/lifetimes.rs:+10:19: +10:28
let _14: &[&str; 3]; // in scope 0 at $DIR/lifetimes.rs:+10:19: +10:28
let _15: [&str; 3]; // in scope 0 at $DIR/lifetimes.rs:+10:19: +10:28
let mut _16: &[core::fmt::ArgumentV1<'_>]; // in scope 0 at $SRC_DIR/std/src/macros.rs:LL:COL
let mut _17: &[core::fmt::ArgumentV1<'_>; 2]; // in scope 0 at $SRC_DIR/std/src/macros.rs:LL:COL
let _18: &[core::fmt::ArgumentV1<'_>; 2]; // in scope 0 at $SRC_DIR/std/src/macros.rs:LL:COL
let _19: [core::fmt::ArgumentV1<'_>; 2]; // in scope 0 at $SRC_DIR/std/src/macros.rs:LL:COL
let mut _20: core::fmt::ArgumentV1<'_>; // in scope 0 at $DIR/lifetimes.rs:+10:20: +10:23
let mut _16: &[core::fmt::rt::Argument<'_>]; // in scope 0 at $SRC_DIR/std/src/macros.rs:LL:COL
let mut _17: &[core::fmt::rt::Argument<'_>; 2]; // in scope 0 at $SRC_DIR/std/src/macros.rs:LL:COL
let _18: &[core::fmt::rt::Argument<'_>; 2]; // in scope 0 at $SRC_DIR/std/src/macros.rs:LL:COL
let _19: [core::fmt::rt::Argument<'_>; 2]; // in scope 0 at $SRC_DIR/std/src/macros.rs:LL:COL
let mut _20: core::fmt::rt::Argument<'_>; // in scope 0 at $DIR/lifetimes.rs:+10:20: +10:23
let mut _21: &std::boxed::Box<dyn std::fmt::Display>; // in scope 0 at $DIR/lifetimes.rs:+10:20: +10:23
let _22: &std::boxed::Box<dyn std::fmt::Display>; // in scope 0 at $DIR/lifetimes.rs:+10:20: +10:23
let mut _23: core::fmt::ArgumentV1<'_>; // in scope 0 at $DIR/lifetimes.rs:+10:24: +10:27
let mut _23: core::fmt::rt::Argument<'_>; // in scope 0 at $DIR/lifetimes.rs:+10:24: +10:27
let mut _24: &u32; // in scope 0 at $DIR/lifetimes.rs:+10:24: +10:27
let _25: &u32; // in scope 0 at $DIR/lifetimes.rs:+10:24: +10:27
let mut _27: bool; // in scope 0 at $DIR/lifetimes.rs:+12:1: +12:2
@ -113,11 +113,11 @@
StorageLive(_22); // scope 4 at $DIR/lifetimes.rs:+10:20: +10:23
_22 = &_8; // scope 4 at $DIR/lifetimes.rs:+10:20: +10:23
_21 = &(*_22); // scope 4 at $DIR/lifetimes.rs:+10:20: +10:23
_20 = core::fmt::ArgumentV1::<'_>::new_display::<Box<dyn std::fmt::Display>>(move _21) -> [return: bb3, unwind unreachable]; // scope 4 at $DIR/lifetimes.rs:+10:20: +10:23
_20 = core::fmt::rt::Argument::<'_>::new_display::<Box<dyn std::fmt::Display>>(move _21) -> [return: bb3, unwind unreachable]; // scope 4 at $DIR/lifetimes.rs:+10:20: +10:23
// mir::Constant
// + span: $DIR/lifetimes.rs:27:20: 27:23
// + user_ty: UserType(4)
// + literal: Const { ty: for<'b> fn(&'b Box<dyn std::fmt::Display>) -> core::fmt::ArgumentV1<'b> {core::fmt::ArgumentV1::<'_>::new_display::<Box<dyn std::fmt::Display>>}, val: Value(<ZST>) }
// + literal: Const { ty: for<'b> fn(&'b Box<dyn std::fmt::Display>) -> core::fmt::rt::Argument<'b> {core::fmt::rt::Argument::<'_>::new_display::<Box<dyn std::fmt::Display>>}, val: Value(<ZST>) }
}
bb3: {
@ -127,11 +127,11 @@
StorageLive(_25); // scope 4 at $DIR/lifetimes.rs:+10:24: +10:27
_25 = &_6; // scope 4 at $DIR/lifetimes.rs:+10:24: +10:27
_24 = &(*_25); // scope 4 at $DIR/lifetimes.rs:+10:24: +10:27
_23 = core::fmt::ArgumentV1::<'_>::new_display::<u32>(move _24) -> [return: bb4, unwind unreachable]; // scope 4 at $DIR/lifetimes.rs:+10:24: +10:27
_23 = core::fmt::rt::Argument::<'_>::new_display::<u32>(move _24) -> [return: bb4, unwind unreachable]; // scope 4 at $DIR/lifetimes.rs:+10:24: +10:27
// mir::Constant
// + span: $DIR/lifetimes.rs:27:24: 27:27
// + user_ty: UserType(5)
// + literal: Const { ty: for<'b> fn(&'b u32) -> core::fmt::ArgumentV1<'b> {core::fmt::ArgumentV1::<'_>::new_display::<u32>}, val: Value(<ZST>) }
// + literal: Const { ty: for<'b> fn(&'b u32) -> core::fmt::rt::Argument<'b> {core::fmt::rt::Argument::<'_>::new_display::<u32>}, val: Value(<ZST>) }
}
bb4: {
@ -141,13 +141,13 @@
StorageDead(_20); // scope 4 at $SRC_DIR/std/src/macros.rs:LL:COL
_18 = &_19; // scope 4 at $SRC_DIR/std/src/macros.rs:LL:COL
_17 = &(*_18); // scope 4 at $SRC_DIR/std/src/macros.rs:LL:COL
_16 = move _17 as &[core::fmt::ArgumentV1<'_>] (Pointer(Unsize)); // scope 4 at $SRC_DIR/std/src/macros.rs:LL:COL
_16 = move _17 as &[core::fmt::rt::Argument<'_>] (Pointer(Unsize)); // scope 4 at $SRC_DIR/std/src/macros.rs:LL:COL
StorageDead(_17); // scope 4 at $SRC_DIR/std/src/macros.rs:LL:COL
_11 = Arguments::<'_>::new_v1(move _12, move _16) -> [return: bb5, unwind unreachable]; // scope 4 at $SRC_DIR/std/src/macros.rs:LL:COL
// mir::Constant
// + span: $SRC_DIR/std/src/macros.rs:LL:COL
// + user_ty: UserType(3)
// + literal: Const { ty: fn(&[&'static str], &[core::fmt::ArgumentV1<'_>]) -> Arguments<'_> {Arguments::<'_>::new_v1}, val: Value(<ZST>) }
// + literal: Const { ty: fn(&[&'static str], &[core::fmt::rt::Argument<'_>]) -> Arguments<'_> {Arguments::<'_>::new_v1}, val: Value(<ZST>) }
}
bb5: {

View File

@ -307,7 +307,7 @@ LL | println!("{} {:.*} {}", 1, 3.2, 4);
= note: expected reference `&usize`
found reference `&{float}`
note: associated function defined here
--> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
--> $SRC_DIR/core/src/fmt/rt.rs:LL:COL
= note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
error[E0308]: mismatched types
@ -321,7 +321,7 @@ LL | println!("{} {:07$.*} {}", 1, 3.2, 4);
= note: expected reference `&usize`
found reference `&{float}`
note: associated function defined here
--> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
--> $SRC_DIR/core/src/fmt/rt.rs:LL:COL
= note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
error: aborting due to 38 previous errors

View File

@ -17,9 +17,9 @@ LL | format!("{:X}", "3");
NonZeroIsize
and 21 others
= note: required for `&str` to implement `UpperHex`
note: required by a bound in `core::fmt::ArgumentV1::<'a>::new_upper_hex`
--> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
= note: this error originates in the macro `$crate::__export::format_args` which comes from the expansion of the macro `arg_new` (in Nightly builds, run with -Z macro-backtrace for more info)
note: required by a bound in `core::fmt::rt::Argument::<'a>::new_upper_hex`
--> $SRC_DIR/core/src/fmt/rt.rs:LL:COL
= note: this error originates in the macro `$crate::__export::format_args` which comes from the expansion of the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
error: aborting due to previous error

View File

@ -1,16 +1,16 @@
error[E0277]: `core::fmt::Opaque` cannot be shared between threads safely
error[E0277]: `core::fmt::rt::Opaque` cannot be shared between threads safely
--> $DIR/send-sync.rs:8:10
|
LL | send(format_args!("{:?}", c));
| ---- ^^^^^^^^^^^^^^^^^^^^^^^ `core::fmt::Opaque` cannot be shared between threads safely
| ---- ^^^^^^^^^^^^^^^^^^^^^^^ `core::fmt::rt::Opaque` cannot be shared between threads safely
| |
| required by a bound introduced by this call
|
= help: within `[core::fmt::ArgumentV1<'_>]`, the trait `Sync` is not implemented for `core::fmt::Opaque`
= note: required because it appears within the type `&core::fmt::Opaque`
= note: required because it appears within the type `ArgumentV1<'_>`
= note: required because it appears within the type `[ArgumentV1<'_>]`
= note: required for `&[core::fmt::ArgumentV1<'_>]` to implement `Send`
= help: within `[core::fmt::rt::Argument<'_>]`, the trait `Sync` is not implemented for `core::fmt::rt::Opaque`
= note: required because it appears within the type `&core::fmt::rt::Opaque`
= note: required because it appears within the type `Argument<'_>`
= note: required because it appears within the type `[Argument<'_>]`
= note: required for `&[core::fmt::rt::Argument<'_>]` to implement `Send`
= note: required because it appears within the type `Arguments<'_>`
note: required by a bound in `send`
--> $DIR/send-sync.rs:1:12
@ -18,19 +18,19 @@ note: required by a bound in `send`
LL | fn send<T: Send>(_: T) {}
| ^^^^ required by this bound in `send`
error[E0277]: `core::fmt::Opaque` cannot be shared between threads safely
error[E0277]: `core::fmt::rt::Opaque` cannot be shared between threads safely
--> $DIR/send-sync.rs:9:10
|
LL | sync(format_args!("{:?}", c));
| ---- ^^^^^^^^^^^^^^^^^^^^^^^ `core::fmt::Opaque` cannot be shared between threads safely
| ---- ^^^^^^^^^^^^^^^^^^^^^^^ `core::fmt::rt::Opaque` cannot be shared between threads safely
| |
| required by a bound introduced by this call
|
= help: within `Arguments<'_>`, the trait `Sync` is not implemented for `core::fmt::Opaque`
= note: required because it appears within the type `&core::fmt::Opaque`
= note: required because it appears within the type `ArgumentV1<'_>`
= note: required because it appears within the type `[ArgumentV1<'_>]`
= note: required because it appears within the type `&[ArgumentV1<'_>]`
= help: within `Arguments<'_>`, the trait `Sync` is not implemented for `core::fmt::rt::Opaque`
= note: required because it appears within the type `&core::fmt::rt::Opaque`
= note: required because it appears within the type `Argument<'_>`
= note: required because it appears within the type `[Argument<'_>]`
= note: required because it appears within the type `&[Argument<'_>]`
= note: required because it appears within the type `Arguments<'_>`
note: required by a bound in `sync`
--> $DIR/send-sync.rs:2:12