Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 695 insertions, 0 deletions

diff --git a/third_party/rust/wast/src/token.rs b/third_party/rust/wast/src/token.rs
new file mode 100644
index 0000000000..a2bcfed5bd
--- /dev/null
+++ b/third_party/rust/wast/src/token.rs
@@ -0,0 +1,695 @@
+//! Common tokens that implement the [`Parse`] trait which are otherwise not
+//! associated specifically with the wasm text format per se (useful in other
+//! contexts too perhaps).
+
+use crate::annotation;
+use crate::lexer::FloatVal;
+use crate::parser::{Cursor, Parse, Parser, Peek, Result};
+use std::fmt;
+use std::hash::{Hash, Hasher};
+use std::str;
+
+/// A position in the original source stream, used to render errors.
+#[derive(Copy, Clone, Debug, PartialOrd, Ord, PartialEq, Eq, Hash)]
+pub struct Span {
+    pub(crate) offset: usize,
+}
+
+impl Span {
+    /// Construct a `Span` from a byte offset in the source file.
+    pub fn from_offset(offset: usize) -> Self {
+        Span { offset }
+    }
+
+    /// Returns the line/column information of this span within `text`.
+    /// Line and column numbers are 0-indexed. User presentation is typically
+    /// 1-indexed, but 0-indexing is appropriate for internal use with
+    /// iterators and slices.
+    pub fn linecol_in(&self, text: &str) -> (usize, usize) {
+        let mut cur = 0;
+        // Use split_terminator instead of lines so that if there is a `\r`,
+        // it is included in the offset calculation. The `+1` values below
+        // account for the `\n`.
+        for (i, line) in text.split_terminator('\n').enumerate() {
+            if cur + line.len() + 1 > self.offset {
+                return (i, self.offset - cur);
+            }
+            cur += line.len() + 1;
+        }
+        (text.lines().count(), 0)
+    }
+
+    /// Returns the byte offset of this span.
+    pub fn offset(&self) -> usize {
+        self.offset
+    }
+}
+
+/// An identifier in a WebAssembly module, prefixed by `$` in the textual
+/// format.
+///
+/// An identifier is used to symbolically refer to items in a a wasm module,
+/// typically via the [`Index`] type.
+#[derive(Copy, Clone)]
+pub struct Id<'a> {
+    name: &'a str,
+    gen: u32,
+    span: Span,
+}
+
+impl<'a> Id<'a> {
+    fn new(name: &'a str, span: Span) -> Id<'a> {
+        Id { name, gen: 0, span }
+    }
+
+    pub(crate) fn gensym(span: Span, gen: u32) -> Id<'a> {
+        Id {
+            name: "gensym",
+            gen,
+            span,
+        }
+    }
+
+    /// Returns the underlying name of this identifier.
+    ///
+    /// The name returned does not contain the leading `$`.
+    pub fn name(&self) -> &'a str {
+        self.name
+    }
+
+    /// Returns span of this identifier in the original source
+    pub fn span(&self) -> Span {
+        self.span
+    }
+
+    pub(crate) fn is_gensym(&self) -> bool {
+        self.gen != 0
+    }
+}
+
+impl<'a> Hash for Id<'a> {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        self.name.hash(hasher);
+        self.gen.hash(hasher);
+    }
+}
+
+impl<'a> PartialEq for Id<'a> {
+    fn eq(&self, other: &Id<'a>) -> bool {
+        self.name == other.name && self.gen == other.gen
+    }
+}
+
+impl<'a> Eq for Id<'a> {}
+
+impl<'a> Parse<'a> for Id<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.step(|c| {
+            if let Some((name, rest)) = c.id() {
+                return Ok((Id::new(name, c.cur_span()), rest));
+            }
+            Err(c.error("expected an identifier"))
+        })
+    }
+}
+
+impl fmt::Debug for Id<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self.gen != 0 {
+            f.debug_struct("Id").field("gen", &self.gen).finish()
+        } else {
+            self.name.fmt(f)
+        }
+    }
+}
+
+impl Peek for Id<'_> {
+    fn peek(cursor: Cursor<'_>) -> bool {
+        cursor.id().is_some()
+    }
+
+    fn display() -> &'static str {
+        "an identifier"
+    }
+}
+
+/// A reference to another item in a wasm module.
+///
+/// This type is used for items referring to other items (such as `call $foo`
+/// referencing function `$foo`). References can be either an index (u32) or an
+/// [`Id`] in the textual format.
+///
+/// The emission phase of a module will ensure that `Index::Id` is never used
+/// and switch them all to `Index::Num`.
+#[derive(Copy, Clone, Debug)]
+pub enum Index<'a> {
+    /// A numerical index that this references. The index space this is
+    /// referencing is implicit based on where this [`Index`] is stored.
+    Num(u32, Span),
+    /// A human-readable identifier this references. Like `Num`, the namespace
+    /// this references is based on where this is stored.
+    Id(Id<'a>),
+}
+
+impl Index<'_> {
+    /// Returns the source location where this `Index` was defined.
+    pub fn span(&self) -> Span {
+        match self {
+            Index::Num(_, span) => *span,
+            Index::Id(id) => id.span(),
+        }
+    }
+
+    pub(crate) fn is_resolved(&self) -> bool {
+        matches!(self, Index::Num(..))
+    }
+}
+
+impl<'a> Parse<'a> for Index<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<Id>() {
+            Ok(Index::Id(parser.parse()?))
+        } else if l.peek::<u32>() {
+            let (val, span) = parser.parse()?;
+            Ok(Index::Num(val, span))
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+impl Peek for Index<'_> {
+    fn peek(cursor: Cursor<'_>) -> bool {
+        u32::peek(cursor) || Id::peek(cursor)
+    }
+
+    fn display() -> &'static str {
+        "an index"
+    }
+}
+
+impl<'a> From<Id<'a>> for Index<'a> {
+    fn from(id: Id<'a>) -> Index<'a> {
+        Index::Id(id)
+    }
+}
+
+impl PartialEq for Index<'_> {
+    fn eq(&self, other: &Index<'_>) -> bool {
+        match (self, other) {
+            (Index::Num(a, _), Index::Num(b, _)) => a == b,
+            (Index::Id(a), Index::Id(b)) => a == b,
+            _ => false,
+        }
+    }
+}
+
+impl Eq for Index<'_> {}
+
+impl Hash for Index<'_> {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        match self {
+            Index::Num(a, _) => {
+                0u8.hash(hasher);
+                a.hash(hasher);
+            }
+            Index::Id(a) => {
+                1u8.hash(hasher);
+                a.hash(hasher);
+            }
+        }
+    }
+}
+
+/// Parses `(func $foo)`
+#[derive(Clone, Debug)]
+#[allow(missing_docs)]
+pub struct ItemRef<'a, K> {
+    pub kind: K,
+    pub idx: Index<'a>,
+}
+
+impl<'a, K: Parse<'a>> Parse<'a> for ItemRef<'a, K> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parens(|parser| {
+            let kind = parser.parse::<K>()?;
+            let idx = parser.parse()?;
+            Ok(ItemRef { kind, idx })
+        })
+    }
+}
+
+impl<'a, K: Peek> Peek for ItemRef<'a, K> {
+    fn peek(cursor: Cursor<'_>) -> bool {
+        match cursor.lparen() {
+            Some(remaining) => K::peek(remaining),
+            None => false,
+        }
+    }
+
+    fn display() -> &'static str {
+        "an item reference"
+    }
+}
+
+/// An `@name` annotation in source, currently of the form `@name "foo"`
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub struct NameAnnotation<'a> {
+    /// The name specified for the item
+    pub name: &'a str,
+}
+
+impl<'a> Parse<'a> for NameAnnotation<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<annotation::name>()?;
+        let name = parser.parse()?;
+        Ok(NameAnnotation { name })
+    }
+}
+
+impl<'a> Parse<'a> for Option<NameAnnotation<'a>> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let _r = parser.register_annotation("name");
+        Ok(if parser.peek2::<annotation::name>() {
+            Some(parser.parens(|p| p.parse())?)
+        } else {
+            None
+        })
+    }
+}
+
+macro_rules! integers {
+    ($($i:ident($u:ident))*) => ($(
+        impl<'a> Parse<'a> for $i {
+            fn parse(parser: Parser<'a>) -> Result<Self> {
+                Ok(parser.parse::<($i, Span)>()?.0)
+            }
+        }
+
+        impl<'a> Parse<'a> for ($i, Span) {
+            fn parse(parser: Parser<'a>) -> Result<Self> {
+                parser.step(|c| {
+                    if let Some((i, rest)) = c.integer() {
+                        let (s, base) = i.val();
+                        let val = $i::from_str_radix(s, base)
+                            .or_else(|_| {
+                                $u::from_str_radix(s, base).map(|i| i as $i)
+                            });
+                        return match val {
+                            Ok(n) => Ok(((n, c.cur_span()), rest)),
+                            Err(_) => Err(c.error(concat!(
+                                "invalid ",
+                                stringify!($i),
+                                " number: constant out of range",
+                            ))),
+                        };
+                    }
+                    Err(c.error(concat!("expected a ", stringify!($i))))
+                })
+            }
+        }
+
+        impl Peek for $i {
+            fn peek(cursor: Cursor<'_>) -> bool {
+                cursor.integer().is_some()
+            }
+
+            fn display() -> &'static str {
+                stringify!($i)
+            }
+        }
+    )*)
+}
+
+integers! {
+    u8(u8) u16(u16) u32(u32) u64(u64)
+    i8(u8) i16(u16) i32(u32) i64(u64)
+}
+
+impl<'a> Parse<'a> for &'a [u8] {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.step(|c| {
+            if let Some((i, rest)) = c.string() {
+                return Ok((i, rest));
+            }
+            Err(c.error("expected a string"))
+        })
+    }
+}
+
+impl Peek for &'_ [u8] {
+    fn peek(cursor: Cursor<'_>) -> bool {
+        cursor.string().is_some()
+    }
+
+    fn display() -> &'static str {
+        "string"
+    }
+}
+
+impl<'a> Parse<'a> for &'a str {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        str::from_utf8(parser.parse()?)
+            .map_err(|_| parser.error_at(parser.prev_span(), "malformed UTF-8 encoding"))
+    }
+}
+
+impl Parse<'_> for String {
+    fn parse(parser: Parser<'_>) -> Result<Self> {
+        Ok(<&str>::parse(parser)?.to_string())
+    }
+}
+
+impl Peek for &'_ str {
+    fn peek(cursor: Cursor<'_>) -> bool {
+        <&[u8]>::peek(cursor)
+    }
+
+    fn display() -> &'static str {
+        <&[u8]>::display()
+    }
+}
+
+macro_rules! float {
+    ($($name:ident => {
+        bits: $int:ident,
+        float: $float:ident,
+        exponent_bits: $exp_bits:tt,
+        name: $parse:ident,
+    })*) => ($(
+        /// A parsed floating-point type
+        #[derive(Debug, Copy, Clone)]
+        pub struct $name {
+            /// The raw bits that this floating point number represents.
+            pub bits: $int,
+        }
+
+        impl<'a> Parse<'a> for $name {
+            fn parse(parser: Parser<'a>) -> Result<Self> {
+                parser.step(|c| {
+                    let (val, rest) = if let Some((f, rest)) = c.float() {
+                        ($parse(f.val()), rest)
+                    } else if let Some((i, rest)) = c.integer() {
+                        let (s, base) = i.val();
+                        (
+                            $parse(&FloatVal::Val {
+                                hex: base == 16,
+                                integral: s.into(),
+                                decimal: None,
+                                exponent: None,
+                            }),
+                            rest,
+                        )
+                    } else {
+                        return Err(c.error("expected a float"));
+                    };
+                    match val {
+                        Some(bits) => Ok(($name { bits }, rest)),
+                        None => Err(c.error("invalid float value: constant out of range")),
+                    }
+                })
+            }
+        }
+
+        fn $parse(val: &FloatVal<'_>) -> Option<$int> {
+            // Compute a few well-known constants about the float representation
+            // given the parameters to the macro here.
+            let width = std::mem::size_of::<$int>() * 8;
+            let neg_offset = width - 1;
+            let exp_offset = neg_offset - $exp_bits;
+            let signif_bits = width - 1 - $exp_bits;
+            let signif_mask = (1 << exp_offset) - 1;
+            let bias = (1 << ($exp_bits - 1)) - 1;
+
+            let (hex, integral, decimal, exponent_str) = match val {
+                // Infinity is when the exponent bits are all set and
+                // the significand is zero.
+                FloatVal::Inf { negative } => {
+                    let exp_bits = (1 << $exp_bits) - 1;
+                    let neg_bit = *negative as $int;
+                    return Some(
+                        (neg_bit << neg_offset) |
+                        (exp_bits << exp_offset)
+                    );
+                }
+
+                // NaN is when the exponent bits are all set and
+                // the significand is nonzero. The default of NaN is
+                // when only the highest bit of the significand is set.
+                FloatVal::Nan { negative, val } => {
+                    let exp_bits = (1 << $exp_bits) - 1;
+                    let neg_bit = *negative as $int;
+                    let signif = val.unwrap_or(1 << (signif_bits - 1)) as $int;
+                    // If the significand is zero then this is actually infinity
+                    // so we fail to parse it.
+                    if signif & signif_mask == 0 {
+                        return None;
+                    }
+                    return Some(
+                        (neg_bit << neg_offset) |
+                        (exp_bits << exp_offset) |
+                        (signif & signif_mask)
+                    );
+                }
+
+                // This is trickier, handle this below
+                FloatVal::Val { hex, integral, decimal, exponent } => {
+                    (hex, integral, decimal, exponent)
+                }
+            };
+
+            // Rely on Rust's standard library to parse base 10 floats
+            // correctly.
+            if !*hex {
+                let mut s = integral.to_string();
+                if let Some(decimal) = decimal {
+                    s.push_str(".");
+                    s.push_str(&decimal);
+                }
+                if let Some(exponent) = exponent_str {
+                    s.push_str("e");
+                    s.push_str(&exponent);
+                }
+                let float = s.parse::<$float>().ok()?;
+                // looks like the `*.wat` format considers infinite overflow to
+                // be invalid.
+                if float.is_infinite() {
+                    return None;
+                }
+                return Some(float.to_bits());
+            }
+
+            // Parsing hex floats is... hard! I don't really know what most of
+            // this below does. It was copied from Gecko's implementation in
+            // `WasmTextToBinary.cpp`. Would love comments on this if you have
+            // them!
+            let decimal = decimal.as_ref().map(|s| &**s).unwrap_or("");
+            let negative = integral.starts_with('-');
+            let integral = integral.trim_start_matches('-').trim_start_matches('0');
+
+            // Do a bunch of work up front to locate the first non-zero digit
+            // to determine the initial exponent. There's a number of
+            // adjustments depending on where the digit was found, but the
+            // general idea here is that I'm not really sure why things are
+            // calculated the way they are but it should match Gecko.
+            let decimal_no_leading = decimal.trim_start_matches('0');
+            let decimal_iter = if integral.is_empty() {
+                decimal_no_leading.chars()
+            } else {
+                decimal.chars()
+            };
+            let mut digits = integral.chars()
+                .map(|c| (to_hex(c) as $int, false))
+                .chain(decimal_iter.map(|c| (to_hex(c) as $int, true)));
+            let lead_nonzero_digit = match digits.next() {
+                Some((c, _)) => c,
+                // No digits? Must be `+0` or `-0`, being careful to handle the
+                // sign encoding here.
+                None if negative => return Some(1 << (width - 1)),
+                None => return Some(0),
+            };
+            let mut significand = 0 as $int;
+            let mut exponent = if !integral.is_empty() {
+                1
+            } else {
+                -((decimal.len() - decimal_no_leading.len() + 1) as i32) + 1
+            };
+            let lz = (lead_nonzero_digit as u8).leading_zeros() as i32 - 4;
+            exponent = exponent.checked_mul(4)?.checked_sub(lz + 1)?;
+            let mut significand_pos = (width - (4 - (lz as usize))) as isize;
+            assert!(significand_pos >= 0);
+            significand |= lead_nonzero_digit << significand_pos;
+
+            // Now that we've got an anchor in the string we parse the remaining
+            // digits. Again, not entirely sure why everything is the way it is
+            // here! This is copied frmo gecko.
+            let mut discarded_extra_nonzero = false;
+            for (digit, decimal) in digits {
+                if !decimal {
+                    exponent += 4;
+                }
+                if significand_pos > -4 {
+                    significand_pos -= 4;
+                }
+
+                if significand_pos >= 0 {
+                    significand |= digit << significand_pos;
+                } else if significand_pos > -4 {
+                    significand |= digit >> (4 - significand_pos);
+                    discarded_extra_nonzero = (digit & !((!0) >> (4 - significand_pos))) != 0;
+                } else if digit != 0 {
+                    discarded_extra_nonzero = true;
+                }
+            }
+
+            exponent = exponent.checked_add(match exponent_str {
+                Some(s) => s.parse::<i32>().ok()?,
+                None => 0,
+            })?;
+            debug_assert!(significand != 0);
+
+            let (encoded_exponent, encoded_significand, discarded_significand) =
+                if exponent <= -bias {
+                    // Underflow to subnormal or zero.
+                    let shift = exp_offset as i32 + exponent + bias;
+                    if shift == 0 {
+                        (0, 0, significand)
+                    } else if shift < 0 || shift >= width as i32 {
+                        (0, 0, 0)
+                    } else {
+                        (
+                            0,
+                            significand >> (width as i32 - shift),
+                            significand << shift,
+                        )
+                    }
+                } else if exponent <= bias {
+                    // Normal (non-zero). The significand's leading 1 is encoded
+                    // implicitly.
+                    (
+                        ((exponent + bias) as $int) << exp_offset,
+                        (significand >> (width - exp_offset - 1)) & signif_mask,
+                        significand << (exp_offset + 1),
+                    )
+                } else {
+                    // Overflow to infinity.
+                    (
+                        ((1 << $exp_bits) - 1) << exp_offset,
+                        0,
+                        0,
+                    )
+                };
+
+            let bits = encoded_exponent | encoded_significand;
+
+            // Apply rounding. If this overflows the significand, it carries
+            // into the exponent bit according to the magic of the IEEE 754
+            // encoding.
+            //
+            // Or rather, the comment above is what Gecko says so it's copied
+            // here too.
+            let msb = 1 << (width - 1);
+            let bits = bits
+                + (((discarded_significand & msb != 0)
+                    && ((discarded_significand & !msb != 0) ||
+                         discarded_extra_nonzero ||
+                         // ties to even
+                         (encoded_significand & 1 != 0))) as $int);
+
+            // Just before we return the bits be sure to handle the sign bit we
+            // found at the beginning.
+            let bits = if negative {
+                bits | (1 << (width - 1))
+            } else {
+                bits
+            };
+            // looks like the `*.wat` format considers infinite overflow to
+            // be invalid.
+            if $float::from_bits(bits).is_infinite() {
+                return None;
+            }
+            Some(bits)
+        }
+
+    )*)
+}
+
+float! {
+    Float32 => {
+        bits: u32,
+        float: f32,
+        exponent_bits: 8,
+        name: strtof,
+    }
+    Float64 => {
+        bits: u64,
+        float: f64,
+        exponent_bits: 11,
+        name: strtod,
+    }
+}
+
+fn to_hex(c: char) -> u8 {
+    match c {
+        'a'..='f' => c as u8 - b'a' + 10,
+        'A'..='F' => c as u8 - b'A' + 10,
+        _ => c as u8 - b'0',
+    }
+}
+
+/// A convenience type to use with [`Parser::peek`](crate::parser::Parser::peek)
+/// to see if the next token is an s-expression.
+pub struct LParen {
+    _priv: (),
+}
+
+impl Peek for LParen {
+    fn peek(cursor: Cursor<'_>) -> bool {
+        cursor.lparen().is_some()
+    }
+
+    fn display() -> &'static str {
+        "left paren"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn hex_strtof() {
+        macro_rules! f {
+            ($a:tt) => (f!(@mk $a, None, None));
+            ($a:tt p $e:tt) => (f!(@mk $a, None, Some($e.into())));
+            ($a:tt . $b:tt) => (f!(@mk $a, Some($b.into()), None));
+            ($a:tt . $b:tt p $e:tt) => (f!(@mk $a, Some($b.into()), Some($e.into())));
+            (@mk $a:tt, $b:expr, $e:expr) => (crate::lexer::FloatVal::Val {
+                hex: true,
+                integral: $a.into(),
+                decimal: $b,
+                exponent: $e
+            });
+        }
+        assert_eq!(super::strtof(&f!("0")), Some(0));
+        assert_eq!(super::strtof(&f!("0" . "0")), Some(0));
+        assert_eq!(super::strtof(&f!("0" . "0" p "2354")), Some(0));
+        assert_eq!(super::strtof(&f!("-0")), Some(1 << 31));
+        assert_eq!(super::strtof(&f!("f32")), Some(0x45732000));
+        assert_eq!(super::strtof(&f!("0" . "f32")), Some(0x3f732000));
+        assert_eq!(super::strtof(&f!("1" . "2")), Some(0x3f900000));
+        assert_eq!(
+            super::strtof(&f!("0" . "00000100000000000" p "-126")),
+            Some(0)
+        );
+        assert_eq!(
+            super::strtof(&f!("1" . "fffff4" p "-106")),
+            Some(0x0afffffa)
+        );
+        assert_eq!(super::strtof(&f!("fffff98" p "-133")), Some(0x0afffffa));
+        assert_eq!(super::strtof(&f!("0" . "081" p "023")), Some(0x48810000));
+        assert_eq!(
+            super::strtof(&f!("1" . "00000100000000000" p "-50")),
+            Some(0x26800000)
+        );
+    }
+}