Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

18 files changed, 1836 insertions, 0 deletions

diff --git a/third_party/rust/cexpr/.cargo-checksum.json b/third_party/rust/cexpr/.cargo-checksum.json
new file mode 100644
index 0000000000..d5454729e0
--- /dev/null
+++ b/third_party/rust/cexpr/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"Cargo.toml":"3300e6f2f5fc184c613a78251df3d1333530c9b54193e137b75c88f6db5a6fa6","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"d9771b8c6cf4426d3846de54c1febe20907f1eeadf7adfb5ade89a83bd9ea77f","bors.toml":"1c81ede536a37edd30fe4e622ff0531b25372403ac9475a5d6c50f14156565a2","rustfmt.toml":"d8e7f616455a670ba75e3e94bf6f88f4c168c481664d12501820c7dfff5c3cc2","src/expr.rs":"dad9327dac3af9d2f5818937aac91000e02d835dc600da6185c06e9e12047b1e","src/lib.rs":"ff218b9b734ab2eaef813a6ee3a907cb5cd71d483dfaa28d44926824a5b6d804","src/literal.rs":"6fdefc0357b8a14444df21b05c90556861dc0466e63a57669786f3ef3a3dc1c3","src/token.rs":"cd1ba6315b0137de9a0711670dd1840ac76c41f3b88dcd1a93ad77e1800c703f","tests/clang.rs":"5bb9807f35f760065d15cb9dfb7d8b79c2f734aef7ba5fe3737154155ed8ee73","tests/input/chars.h":"69c8141870872b795b5174bad125b748732c2b01d0e98ffcfc37b19f3f791f69","tests/input/fail.h":"b0b6cffd2dd17410b5eb02ee79ab75754820480b960db8a9866cc9983bd36b65","tests/input/floats.h":"28ec664e793c494e1a31f3bc5b790014e9921fc741bf475a86319b9a9eee5915","tests/input/int_signed.h":"934199eded85dd7820ca08c0beb1381ee6d9339970d2720a69c23025571707ce","tests/input/int_unsigned.h":"7b8023ba468ec76b184912692bc40e8fbcdd92ad86ec5a7c0dbcb02f2b8d961d","tests/input/strings.h":"2dd11bc066f34e8cb1916a28353e9e9a3a21cd406651b2f94fc47e89c95d9cba","tests/input/test_llvm_bug_9069.h":"8d9ae1d1eadc8f6d5c14296f984547fe894d0f2ce5cd6d7aa8caad40a56bc5e1"},"package":"6fac387a98bb7c37292057cffc56d62ecb629900026402633ae9160df93a8766"}
\ No newline at end of file
diff --git a/third_party/rust/cexpr/Cargo.toml b/third_party/rust/cexpr/Cargo.toml
new file mode 100644
index 0000000000..4956001cdd
--- /dev/null
+++ b/third_party/rust/cexpr/Cargo.toml
@@ -0,0 +1,29 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2018"
+name = "cexpr"
+version = "0.6.0"
+authors = ["Jethro Beekman <jethro@jbeekman.nl>"]
+description = "A C expression parser and evaluator"
+documentation = "https://docs.rs/cexpr/"
+keywords = ["C", "expression", "parser"]
+license = "Apache-2.0/MIT"
+repository = "https://github.com/jethrogb/rust-cexpr"
+[dependencies.nom]
+version = "7"
+features = ["std"]
+default-features = false
+[dev-dependencies.clang-sys]
+version = ">= 0.13.0, < 0.29.0"
+[badges.travis-ci]
+repository = "jethrogb/rust-cexpr"
diff --git a/third_party/rust/cexpr/LICENSE-APACHE b/third_party/rust/cexpr/LICENSE-APACHE
new file mode 100644
index 0000000000..16fe87b06e
--- /dev/null
+++ b/third_party/rust/cexpr/LICENSE-APACHE
@@ -0,0 +1,201 @@
+                              Apache License
+                        Version 2.0, January 2004
+                     http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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+   Contributor provides its Contributions) on an "AS IS" BASIS,
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+   implied, including, without limitation, any warranties or conditions
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+   appropriateness of using or redistributing the Work and assume any
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+8. Limitation of Liability. In no event and under no legal theory,
+   whether in tort (including negligence), contract, or otherwise,
+   unless required by applicable law (such as deliberate and grossly
+   negligent acts) or agreed to in writing, shall any Contributor be
+   liable to You for damages, including any direct, indirect, special,
+   incidental, or consequential damages of any character arising as a
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+   Work (including but not limited to damages for loss of goodwill,
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+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
+
+   To apply the Apache License to your work, attach the following
+   boilerplate notice, with the fields enclosed by brackets "[]"
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+   file or class name and description of purpose be included on the
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+Copyright [yyyy] [name of copyright owner]
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
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diff --git a/third_party/rust/cexpr/LICENSE-MIT b/third_party/rust/cexpr/LICENSE-MIT
new file mode 100644
index 0000000000..ed958e7ade
--- /dev/null
+++ b/third_party/rust/cexpr/LICENSE-MIT
@@ -0,0 +1,25 @@
+(C) Copyright 2016 Jethro G. Beekman
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/third_party/rust/cexpr/bors.toml b/third_party/rust/cexpr/bors.toml
new file mode 100644
index 0000000000..ca08e818bf
--- /dev/null
+++ b/third_party/rust/cexpr/bors.toml
@@ -0,0 +1,3 @@
+status = [
+  "continuous-integration/travis-ci/push",
+]
diff --git a/third_party/rust/cexpr/rustfmt.toml b/third_party/rust/cexpr/rustfmt.toml
new file mode 100644
index 0000000000..32a9786fa1
--- /dev/null
+++ b/third_party/rust/cexpr/rustfmt.toml
@@ -0,0 +1 @@
+edition = "2018"
diff --git a/third_party/rust/cexpr/src/expr.rs b/third_party/rust/cexpr/src/expr.rs
new file mode 100644
index 0000000000..7f7e458bd4
--- /dev/null
+++ b/third_party/rust/cexpr/src/expr.rs
@@ -0,0 +1,610 @@
+// (C) Copyright 2016 Jethro G. Beekman
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//! Evaluating C expressions from tokens.
+//!
+//! Numerical operators are supported. All numerical values are treated as
+//! `i64` or `f64`. Type casting is not supported. `i64` are converted to
+//! `f64` when used in conjunction with a `f64`. Right shifts are always
+//! arithmetic shifts.
+//!
+//! The `sizeof` operator is not supported.
+//!
+//! String concatenation is supported, but width prefixes are ignored; all
+//! strings are treated as narrow strings.
+//!
+//! Use the `IdentifierParser` to substitute identifiers found in expressions.
+
+use std::collections::HashMap;
+use std::num::Wrapping;
+use std::ops::{
+    AddAssign, BitAndAssign, BitOrAssign, BitXorAssign, DivAssign, MulAssign, RemAssign, ShlAssign,
+    ShrAssign, SubAssign,
+};
+
+use crate::literal::{self, CChar};
+use crate::token::{Kind as TokenKind, Token};
+use crate::ToCexprResult;
+use nom::branch::alt;
+use nom::combinator::{complete, map, map_opt};
+use nom::multi::{fold_many0, many0, separated_list0};
+use nom::sequence::{delimited, pair, preceded};
+use nom::*;
+
+/// Expression parser/evaluator that supports identifiers.
+#[derive(Debug)]
+pub struct IdentifierParser<'ident> {
+    identifiers: &'ident HashMap<Vec<u8>, EvalResult>,
+}
+#[derive(Copy, Clone)]
+struct PRef<'a>(&'a IdentifierParser<'a>);
+
+/// A shorthand for the type of cexpr expression evaluation results.
+pub type CResult<'a, R> = IResult<&'a [Token], R, crate::Error<&'a [Token]>>;
+
+/// The result of parsing a literal or evaluating an expression.
+#[derive(Debug, Clone, PartialEq)]
+#[allow(missing_docs)]
+pub enum EvalResult {
+    Int(Wrapping<i64>),
+    Float(f64),
+    Char(CChar),
+    Str(Vec<u8>),
+    Invalid,
+}
+
+macro_rules! result_opt (
+	(fn $n:ident: $e:ident -> $t:ty) => (
+		#[allow(dead_code)]
+        #[allow(clippy::wrong_self_convention)]
+		fn $n(self) -> Option<$t> {
+			if let EvalResult::$e(v) = self {
+				Some(v)
+			} else {
+				None
+			}
+		}
+	);
+);
+
+impl EvalResult {
+    result_opt!(fn as_int: Int -> Wrapping<i64>);
+    result_opt!(fn as_float: Float -> f64);
+    result_opt!(fn as_char: Char -> CChar);
+    result_opt!(fn as_str: Str -> Vec<u8>);
+
+    #[allow(clippy::wrong_self_convention)]
+    fn as_numeric(self) -> Option<EvalResult> {
+        match self {
+            EvalResult::Int(_) | EvalResult::Float(_) => Some(self),
+            _ => None,
+        }
+    }
+}
+
+impl From<Vec<u8>> for EvalResult {
+    fn from(s: Vec<u8>) -> EvalResult {
+        EvalResult::Str(s)
+    }
+}
+
+// ===========================================
+// ============= Clang tokens ================
+// ===========================================
+
+macro_rules! exact_token (
+	($k:ident, $c:expr) => ({
+        move |input: &[Token]| {
+		if input.is_empty() {
+			let res: CResult<'_, &[u8]> = Err(crate::nom::Err::Incomplete(Needed::new($c.len())));
+			res
+		} else {
+			if input[0].kind==TokenKind::$k && &input[0].raw[..]==$c {
+				Ok((&input[1..], &input[0].raw[..]))
+			} else {
+				Err(crate::nom::Err::Error((input, crate::ErrorKind::ExactToken(TokenKind::$k,$c)).into()))
+			}
+		}
+        }
+	});
+);
+
+fn identifier_token(input: &[Token]) -> CResult<'_, &[u8]> {
+    if input.is_empty() {
+        let res: CResult<'_, &[u8]> = Err(nom::Err::Incomplete(Needed::new(1)));
+        res
+    } else {
+        if input[0].kind == TokenKind::Identifier {
+            Ok((&input[1..], &input[0].raw[..]))
+        } else {
+            Err(crate::nom::Err::Error((input, crate::ErrorKind::TypedToken(TokenKind::Identifier)).into()))
+        }
+    }
+}
+
+fn p(c: &'static str) -> impl Fn(&[Token]) -> CResult<'_, &[u8]> {
+    exact_token!(Punctuation, c.as_bytes())
+}
+
+fn one_of_punctuation(c: &'static [&'static str]) -> impl Fn(&[Token]) -> CResult<'_, &[u8]> {
+    move |input| {
+        if input.is_empty() {
+            let min = c
+                .iter()
+                .map(|opt| opt.len())
+                .min()
+                .expect("at least one option");
+            Err(crate::nom::Err::Incomplete(Needed::new(min)))
+        } else if input[0].kind == TokenKind::Punctuation
+            && c.iter().any(|opt| opt.as_bytes() == &input[0].raw[..])
+        {
+            Ok((&input[1..], &input[0].raw[..]))
+        } else {
+            Err(crate::nom::Err::Error(
+                (
+                    input,
+                    crate::ErrorKind::ExactTokens(TokenKind::Punctuation, c),
+                )
+                    .into(),
+            ))
+        }
+    }
+}
+
+// ==================================================
+// ============= Numeric expressions ================
+// ==================================================
+
+impl<'a> AddAssign<&'a EvalResult> for EvalResult {
+    fn add_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a + b),
+            (&Float(a), &Int(b)) => Float(a + (b.0 as f64)),
+            (&Int(a), &Float(b)) => Float(a.0 as f64 + b),
+            (&Float(a), &Float(b)) => Float(a + b),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> BitAndAssign<&'a EvalResult> for EvalResult {
+    fn bitand_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a & b),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> BitOrAssign<&'a EvalResult> for EvalResult {
+    fn bitor_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a | b),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> BitXorAssign<&'a EvalResult> for EvalResult {
+    fn bitxor_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a ^ b),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> DivAssign<&'a EvalResult> for EvalResult {
+    fn div_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a / b),
+            (&Float(a), &Int(b)) => Float(a / (b.0 as f64)),
+            (&Int(a), &Float(b)) => Float(a.0 as f64 / b),
+            (&Float(a), &Float(b)) => Float(a / b),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> MulAssign<&'a EvalResult> for EvalResult {
+    fn mul_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a * b),
+            (&Float(a), &Int(b)) => Float(a * (b.0 as f64)),
+            (&Int(a), &Float(b)) => Float(a.0 as f64 * b),
+            (&Float(a), &Float(b)) => Float(a * b),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> RemAssign<&'a EvalResult> for EvalResult {
+    fn rem_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a % b),
+            (&Float(a), &Int(b)) => Float(a % (b.0 as f64)),
+            (&Int(a), &Float(b)) => Float(a.0 as f64 % b),
+            (&Float(a), &Float(b)) => Float(a % b),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> ShlAssign<&'a EvalResult> for EvalResult {
+    fn shl_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a << (b.0 as usize)),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> ShrAssign<&'a EvalResult> for EvalResult {
+    fn shr_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a >> (b.0 as usize)),
+            _ => Invalid,
+        };
+    }
+}
+impl<'a> SubAssign<&'a EvalResult> for EvalResult {
+    fn sub_assign(&mut self, rhs: &'a EvalResult) {
+        use self::EvalResult::*;
+        *self = match (&*self, rhs) {
+            (&Int(a), &Int(b)) => Int(a - b),
+            (&Float(a), &Int(b)) => Float(a - (b.0 as f64)),
+            (&Int(a), &Float(b)) => Float(a.0 as f64 - b),
+            (&Float(a), &Float(b)) => Float(a - b),
+            _ => Invalid,
+        };
+    }
+}
+
+fn unary_op(input: (&[u8], EvalResult)) -> Option<EvalResult> {
+    use self::EvalResult::*;
+    assert_eq!(input.0.len(), 1);
+    match (input.0[0], input.1) {
+        (b'+', i) => Some(i),
+        (b'-', Int(i)) => Some(Int(Wrapping(i.0.wrapping_neg()))), // impl Neg for Wrapping not until rust 1.10...
+        (b'-', Float(i)) => Some(Float(-i)),
+        (b'-', _) => unreachable!("non-numeric unary op"),
+        (b'~', Int(i)) => Some(Int(!i)),
+        (b'~', Float(_)) => None,
+        (b'~', _) => unreachable!("non-numeric unary op"),
+        _ => unreachable!("invalid unary op"),
+    }
+}
+
+fn numeric<I: Clone, E: nom::error::ParseError<I>, F>(
+    f: F,
+) -> impl FnMut(I) -> nom::IResult<I, EvalResult, E>
+where
+    F: FnMut(I) -> nom::IResult<I, EvalResult, E>,
+{
+    nom::combinator::map_opt(f, EvalResult::as_numeric)
+}
+
+impl<'a> PRef<'a> {
+    fn unary(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        alt((
+            delimited(p("("), |i| self.numeric_expr(i), p(")")),
+            numeric(|i| self.literal(i)),
+            numeric(|i| self.identifier(i)),
+            map_opt(
+                pair(one_of_punctuation(&["+", "-", "~"][..]), |i| self.unary(i)),
+                unary_op,
+            ),
+        ))(input)
+    }
+
+    fn mul_div_rem(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        let (input, acc) = self.unary(input)?;
+        fold_many0(
+            pair(complete(one_of_punctuation(&["*", "/", "%"][..])), |i| {
+                self.unary(i)
+            }),
+            move || acc.clone(),
+            |mut acc, (op, val): (&[u8], EvalResult)| {
+                match op[0] as char {
+                    '*' => acc *= &val,
+                    '/' => acc /= &val,
+                    '%' => acc %= &val,
+                    _ => unreachable!(),
+                };
+                acc
+            },
+        )(input)
+    }
+
+    fn add_sub(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        let (input, acc) = self.mul_div_rem(input)?;
+        fold_many0(
+            pair(complete(one_of_punctuation(&["+", "-"][..])), |i| {
+                self.mul_div_rem(i)
+            }),
+            move || acc.clone(),
+            |mut acc, (op, val): (&[u8], EvalResult)| {
+                match op[0] as char {
+                    '+' => acc += &val,
+                    '-' => acc -= &val,
+                    _ => unreachable!(),
+                };
+                acc
+            },
+        )(input)
+    }
+
+    fn shl_shr(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        let (input, acc) = self.add_sub(input)?;
+        numeric(fold_many0(
+            pair(complete(one_of_punctuation(&["<<", ">>"][..])), |i| {
+                self.add_sub(i)
+            }),
+            move || acc.clone(),
+            |mut acc, (op, val): (&[u8], EvalResult)| {
+                match op {
+                    b"<<" => acc <<= &val,
+                    b">>" => acc >>= &val,
+                    _ => unreachable!(),
+                };
+                acc
+            },
+        ))(input)
+    }
+
+    fn and(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        let (input, acc) = self.shl_shr(input)?;
+        numeric(fold_many0(
+            preceded(complete(p("&")), |i| self.shl_shr(i)),
+            move || acc.clone(),
+            |mut acc, val: EvalResult| {
+                acc &= &val;
+                acc
+            },
+        ))(input)
+    }
+
+    fn xor(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        let (input, acc) = self.and(input)?;
+        numeric(fold_many0(
+            preceded(complete(p("^")), |i| self.and(i)),
+            move || acc.clone(),
+            |mut acc, val: EvalResult| {
+                acc ^= &val;
+                acc
+            },
+        ))(input)
+    }
+
+    fn or(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        let (input, acc) = self.xor(input)?;
+        numeric(fold_many0(
+            preceded(complete(p("|")), |i| self.xor(i)),
+            move || acc.clone(),
+            |mut acc, val: EvalResult| {
+                acc |= &val;
+                acc
+            },
+        ))(input)
+    }
+
+    #[inline(always)]
+    fn numeric_expr(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        self.or(input)
+    }
+}
+
+// =======================================================
+// ============= Literals and identifiers ================
+// =======================================================
+
+impl<'a> PRef<'a> {
+    fn identifier(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        match input.split_first() {
+            None => Err(Err::Incomplete(Needed::new(1))),
+            Some((
+                &Token {
+                    kind: TokenKind::Identifier,
+                    ref raw,
+                },
+                rest,
+            )) => {
+                if let Some(r) = self.identifiers.get(&raw[..]) {
+                    Ok((rest, r.clone()))
+                } else {
+                    Err(Err::Error(
+                        (input, crate::ErrorKind::UnknownIdentifier).into(),
+                    ))
+                }
+            }
+            Some(_) => Err(Err::Error(
+                (input, crate::ErrorKind::TypedToken(TokenKind::Identifier)).into(),
+            )),
+        }
+    }
+
+    fn literal(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        match input.split_first() {
+            None => Err(Err::Incomplete(Needed::new(1))),
+            Some((
+                &Token {
+                    kind: TokenKind::Literal,
+                    ref raw,
+                },
+                rest,
+            )) => match literal::parse(raw) {
+                Ok((_, result)) => Ok((rest, result)),
+                _ => Err(Err::Error((input, crate::ErrorKind::InvalidLiteral).into())),
+            },
+            Some(_) => Err(Err::Error(
+                (input, crate::ErrorKind::TypedToken(TokenKind::Literal)).into(),
+            )),
+        }
+    }
+
+    fn string(self, input: &'_ [Token]) -> CResult<'_, Vec<u8>> {
+        alt((
+            map_opt(|i| self.literal(i), EvalResult::as_str),
+            map_opt(|i| self.identifier(i), EvalResult::as_str),
+        ))(input)
+        .to_cexpr_result()
+    }
+
+    // "string1" "string2" etc...
+    fn concat_str(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        map(
+            pair(|i| self.string(i), many0(complete(|i| self.string(i)))),
+            |(first, v)| {
+                Vec::into_iter(v)
+                    .fold(first, |mut s, elem| {
+                        Vec::extend_from_slice(&mut s, Vec::<u8>::as_slice(&elem));
+                        s
+                    })
+                    .into()
+            },
+        )(input)
+        .to_cexpr_result()
+    }
+
+    fn expr(self, input: &'_ [Token]) -> CResult<'_, EvalResult> {
+        alt((
+            |i| self.numeric_expr(i),
+            delimited(p("("), |i| self.expr(i), p(")")),
+            |i| self.concat_str(i),
+            |i| self.literal(i),
+            |i| self.identifier(i),
+        ))(input)
+        .to_cexpr_result()
+    }
+
+    fn macro_definition(self, input: &'_ [Token]) -> CResult<'_, (&'_ [u8], EvalResult)> {
+        pair(identifier_token, |i| self.expr(i))(input)
+    }
+}
+
+impl<'a> ::std::ops::Deref for PRef<'a> {
+    type Target = IdentifierParser<'a>;
+    fn deref(&self) -> &IdentifierParser<'a> {
+        self.0
+    }
+}
+
+impl<'ident> IdentifierParser<'ident> {
+    fn as_ref(&self) -> PRef<'_> {
+        PRef(self)
+    }
+
+    /// Create a new `IdentifierParser` with a set of known identifiers. When
+    /// a known identifier is encountered during parsing, it is substituted
+    /// for the value specified.
+    pub fn new(identifiers: &HashMap<Vec<u8>, EvalResult>) -> IdentifierParser<'_> {
+        IdentifierParser { identifiers }
+    }
+
+    /// Parse and evaluate an expression of a list of tokens.
+    ///
+    /// Returns an error if the input is not a valid expression or if the token
+    /// stream contains comments, keywords or unknown identifiers.
+    pub fn expr<'a>(&self, input: &'a [Token]) -> CResult<'a, EvalResult> {
+        self.as_ref().expr(input)
+    }
+
+    /// Parse and evaluate a macro definition from a list of tokens.
+    ///
+    /// Returns the identifier for the macro and its replacement evaluated as an
+    /// expression. The input should not include `#define`.
+    ///
+    /// Returns an error if the replacement is not a valid expression, if called
+    /// on most function-like macros, or if the token stream contains comments,
+    /// keywords or unknown identifiers.
+    ///
+    /// N.B. This is intended to fail on function-like macros, but if it the
+    /// macro takes a single argument, the argument name is defined as an
+    /// identifier, and the macro otherwise parses as an expression, it will
+    /// return a result even on function-like macros.
+    ///
+    /// ```c
+    /// // will evaluate into IDENTIFIER
+    /// #define DELETE(IDENTIFIER)
+    /// // will evaluate into IDENTIFIER-3
+    /// #define NEGATIVE_THREE(IDENTIFIER)  -3
+    /// ```
+    pub fn macro_definition<'a>(&self, input: &'a [Token]) -> CResult<'a, (&'a [u8], EvalResult)> {
+        crate::assert_full_parse(self.as_ref().macro_definition(input))
+    }
+}
+
+/// Parse and evaluate an expression of a list of tokens.
+///
+/// Returns an error if the input is not a valid expression or if the token
+/// stream contains comments, keywords or identifiers.
+pub fn expr(input: &[Token]) -> CResult<'_, EvalResult> {
+    IdentifierParser::new(&HashMap::new()).expr(input)
+}
+
+/// Parse and evaluate a macro definition from a list of tokens.
+///
+/// Returns the identifier for the macro and its replacement evaluated as an
+/// expression. The input should not include `#define`.
+///
+/// Returns an error if the replacement is not a valid expression, if called
+/// on a function-like macro, or if the token stream contains comments,
+/// keywords or identifiers.
+pub fn macro_definition(input: &[Token]) -> CResult<'_, (&'_ [u8], EvalResult)> {
+    IdentifierParser::new(&HashMap::new()).macro_definition(input)
+}
+
+/// Parse a functional macro declaration from a list of tokens.
+///
+/// Returns the identifier for the macro and the argument list (in order). The
+/// input should not include `#define`. The actual definition is not parsed and
+/// may be obtained from the unparsed data returned.
+///
+/// Returns an error if the input is not a functional macro or if the token
+/// stream contains comments.
+///
+/// # Example
+/// ```
+/// use cexpr::expr::{IdentifierParser, EvalResult, fn_macro_declaration};
+/// use cexpr::assert_full_parse;
+/// use cexpr::token::Kind::*;
+/// use cexpr::token::Token;
+///
+/// // #define SUFFIX(arg) arg "suffix"
+/// let tokens = vec![
+///     (Identifier,  &b"SUFFIX"[..]).into(),
+///     (Punctuation, &b"("[..]).into(),
+///     (Identifier,  &b"arg"[..]).into(),
+///     (Punctuation, &b")"[..]).into(),
+///     (Identifier,  &b"arg"[..]).into(),
+///     (Literal,     &br#""suffix""#[..]).into(),
+/// ];
+///
+/// // Try to parse the functional part
+/// let (expr, (ident, args)) = fn_macro_declaration(&tokens).unwrap();
+/// assert_eq!(ident, b"SUFFIX");
+///
+/// // Create dummy arguments
+/// let idents = args.into_iter().map(|arg|
+///     (arg.to_owned(), EvalResult::Str(b"test".to_vec()))
+/// ).collect();
+///
+/// // Evaluate the macro
+/// let (_, evaluated) = assert_full_parse(IdentifierParser::new(&idents).expr(expr)).unwrap();
+/// assert_eq!(evaluated, EvalResult::Str(b"testsuffix".to_vec()));
+/// ```
+pub fn fn_macro_declaration(input: &[Token]) -> CResult<'_, (&[u8], Vec<&[u8]>)> {
+    pair(
+        identifier_token,
+        delimited(
+            p("("),
+            separated_list0(p(","), identifier_token),
+            p(")"),
+        ),
+    )(input)
+}
diff --git a/third_party/rust/cexpr/src/lib.rs b/third_party/rust/cexpr/src/lib.rs
new file mode 100644
index 0000000000..5170f97d13
--- /dev/null
+++ b/third_party/rust/cexpr/src/lib.rs
@@ -0,0 +1,149 @@
+// (C) Copyright 2016 Jethro G. Beekman
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//! A C expression parser and evaluator.
+//!
+//! This crate provides methods for parsing and evaluating simple C expressions. In general, the
+//! crate can handle most arithmetic expressions that would appear in macros or the definition of
+//! constants, as well as string and character constants.
+//!
+//! The main entry point for is [`token::parse`], which parses a byte string and returns its
+//! evaluated value.
+#![warn(rust_2018_idioms)]
+#![warn(missing_docs)]
+#![allow(deprecated)]
+
+pub mod nom {
+    //! nom's result types, re-exported.
+    pub use nom::{error::ErrorKind, error::Error, Err, IResult, Needed};
+}
+pub mod expr;
+pub mod literal;
+pub mod token;
+
+/// Parsing errors specific to C parsing
+#[derive(Debug)]
+pub enum ErrorKind {
+    /// Expected the specified token
+    ExactToken(token::Kind, &'static [u8]),
+    /// Expected one of the specified tokens
+    ExactTokens(token::Kind, &'static [&'static str]),
+    /// Expected a token of the specified kind
+    TypedToken(token::Kind),
+    /// An unknown identifier was encountered
+    UnknownIdentifier,
+    /// An invalid literal was encountered.
+    ///
+    /// When encountered, this generally means a bug exists in the data that
+    /// was passed in or the parsing logic.
+    InvalidLiteral,
+    /// A full parse was requested, but data was left over after parsing finished.
+    Partial,
+    /// An error occurred in an underlying nom parser.
+    Parser(nom::ErrorKind),
+}
+
+impl From<nom::ErrorKind> for ErrorKind {
+    fn from(k: nom::ErrorKind) -> Self {
+        ErrorKind::Parser(k)
+    }
+}
+
+impl From<u32> for ErrorKind {
+    fn from(_: u32) -> Self {
+        ErrorKind::InvalidLiteral
+    }
+}
+
+/// Parsing errors specific to C parsing.
+///
+/// This is a superset of `(I, nom::ErrorKind)` that includes the additional errors specified by
+/// [`ErrorKind`].
+#[derive(Debug)]
+pub struct Error<I> {
+    /// The remainder of the input stream at the time of the error.
+    pub input: I,
+    /// The error that occurred.
+    pub error: ErrorKind,
+}
+
+impl<I> From<(I, nom::ErrorKind)> for Error<I> {
+    fn from(e: (I, nom::ErrorKind)) -> Self {
+        Self::from((e.0, ErrorKind::from(e.1)))
+    }
+}
+
+impl<I> From<(I, ErrorKind)> for Error<I> {
+    fn from(e: (I, ErrorKind)) -> Self {
+        Self {
+            input: e.0,
+            error: e.1,
+        }
+    }
+}
+
+impl<I> From<::nom::error::Error<I>> for Error<I> {
+    fn from(e: ::nom::error::Error<I>) -> Self {
+        Self {
+            input: e.input,
+            error: e.code.into(),
+        }
+    }
+}
+
+impl<I> ::nom::error::ParseError<I> for Error<I> {
+    fn from_error_kind(input: I, kind: nom::ErrorKind) -> Self {
+        Self {
+            input,
+            error: kind.into(),
+        }
+    }
+
+    fn append(_: I, _: nom::ErrorKind, other: Self) -> Self {
+        other
+    }
+}
+
+// in lieu of https://github.com/Geal/nom/issues/1010
+trait ToCexprResult<I, O> {
+    fn to_cexpr_result(self) -> nom::IResult<I, O, Error<I>>;
+}
+impl<I, O, E> ToCexprResult<I, O> for nom::IResult<I, O, E>
+where
+    Error<I>: From<E>,
+{
+    fn to_cexpr_result(self) -> nom::IResult<I, O, Error<I>> {
+        match self {
+            Ok(v) => Ok(v),
+            Err(nom::Err::Incomplete(n)) => Err(nom::Err::Incomplete(n)),
+            Err(nom::Err::Error(e)) => Err(nom::Err::Error(e.into())),
+            Err(nom::Err::Failure(e)) => Err(nom::Err::Failure(e.into())),
+        }
+    }
+}
+
+/// If the input result indicates a succesful parse, but there is data left,
+/// return an `Error::Partial` instead.
+pub fn assert_full_parse<'i, I: 'i, O, E>(
+    result: nom::IResult<&'i [I], O, E>,
+) -> nom::IResult<&'i [I], O, Error<&'i [I]>>
+where
+    Error<&'i [I]>: From<E>,
+{
+    match result.to_cexpr_result() {
+        Ok((rem, output)) => {
+            if rem.is_empty() {
+                Ok((rem, output))
+            } else {
+                Err(nom::Err::Error((rem, ErrorKind::Partial).into()))
+            }
+        }
+        Err(nom::Err::Incomplete(n)) => Err(nom::Err::Incomplete(n)),
+        Err(nom::Err::Failure(e)) => Err(nom::Err::Failure(e)),
+        Err(nom::Err::Error(e)) => Err(nom::Err::Error(e)),
+    }
+}
diff --git a/third_party/rust/cexpr/src/literal.rs b/third_party/rust/cexpr/src/literal.rs
new file mode 100644
index 0000000000..68e85c7dad
--- /dev/null
+++ b/third_party/rust/cexpr/src/literal.rs
@@ -0,0 +1,361 @@
+// (C) Copyright 2016 Jethro G. Beekman
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//! Parsing C literals from byte slices.
+//!
+//! This will parse a representation of a C literal into a Rust type.
+//!
+//! # characters
+//! Character literals are stored into the `CChar` type, which can hold values
+//! that are not valid Unicode code points. ASCII characters are represented as
+//! `char`, literal bytes with the high byte set are converted into the raw
+//! representation. Escape sequences are supported. If hex and octal escapes
+//! map to an ASCII character, that is used, otherwise, the raw encoding is
+//! used, including for values over 255. Unicode escapes are checked for
+//! validity and mapped to `char`. Character sequences are not supported. Width
+//! prefixes are ignored.
+//!
+//! # strings
+//! Strings are interpreted as byte vectors. Escape sequences are supported. If
+//! hex and octal escapes map onto multi-byte characters, they are truncated to
+//! one 8-bit character. Unicode escapes are converted into their UTF-8
+//! encoding. Width prefixes are ignored.
+//!
+//! # integers
+//! Integers are read into `i64`. Binary, octal, decimal and hexadecimal are
+//! all supported. If the literal value is between `i64::MAX` and `u64::MAX`,
+//! it is bit-cast to `i64`. Values over `u64::MAX` cannot be parsed. Width and
+//! sign suffixes are ignored. Sign prefixes are not supported.
+//!
+//! # real numbers
+//! Reals are read into `f64`. Width suffixes are ignored. Sign prefixes are
+//! not supported in the significand. Hexadecimal floating points are not
+//! supported.
+
+use std::char;
+use std::str::{self, FromStr};
+
+use nom::branch::alt;
+use nom::bytes::complete::is_not;
+use nom::bytes::complete::tag;
+use nom::character::complete::{char, one_of};
+use nom::combinator::{complete, map, map_opt, opt, recognize};
+use nom::multi::{fold_many0, many0, many1, many_m_n};
+use nom::sequence::{delimited, pair, preceded, terminated, tuple};
+use nom::*;
+
+use crate::expr::EvalResult;
+use crate::ToCexprResult;
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+/// Representation of a C character
+pub enum CChar {
+    /// A character that can be represented as a `char`
+    Char(char),
+    /// Any other character (8-bit characters, unicode surrogates, etc.)
+    Raw(u64),
+}
+
+impl From<u8> for CChar {
+    fn from(i: u8) -> CChar {
+        match i {
+            0..=0x7f => CChar::Char(i as u8 as char),
+            _ => CChar::Raw(i as u64),
+        }
+    }
+}
+
+// A non-allocating version of this would be nice...
+impl std::convert::Into<Vec<u8>> for CChar {
+    fn into(self) -> Vec<u8> {
+        match self {
+            CChar::Char(c) => {
+                let mut s = String::with_capacity(4);
+                s.extend(&[c]);
+                s.into_bytes()
+            }
+            CChar::Raw(i) => {
+                let mut v = Vec::with_capacity(1);
+                v.push(i as u8);
+                v
+            }
+        }
+    }
+}
+
+/// ensures the child parser consumes the whole input
+pub fn full<I: Clone, O, F>(
+    f: F,
+) -> impl Fn(I) -> nom::IResult<I, O>
+where
+    I: nom::InputLength,
+    F: Fn(I) -> nom::IResult<I, O>,
+{
+    move |input| {
+        let res = f(input);
+        match res {
+            Ok((i, o)) => {
+                if i.input_len() == 0 {
+                    Ok((i, o))
+                } else {
+                    Err(nom::Err::Error(nom::error::Error::new(i, nom::error::ErrorKind::Complete)))
+                }
+            }
+            r => r,
+        }
+    }
+}
+
+// =================================
+// ======== matching digits ========
+// =================================
+
+macro_rules! byte {
+	($($p: pat)|* ) => {{
+        fn parser(i: &[u8]) -> crate::nom::IResult<&[u8], u8> {
+            match i.split_first() {
+                $(Some((&c @ $p,rest)))|* => Ok((rest,c)),
+                Some(_) => Err(nom::Err::Error(nom::error::Error::new(i, nom::error::ErrorKind::OneOf))),
+                None => Err(nom::Err::Incomplete(Needed::new(1))),
+            }
+        }
+
+        parser
+	}}
+}
+
+fn binary(i: &[u8]) -> nom::IResult<&[u8], u8> {
+    byte!(b'0'..=b'1')(i)
+}
+
+fn octal(i: &[u8]) -> nom::IResult<&[u8], u8> {
+    byte!(b'0'..=b'7')(i)
+}
+
+fn decimal(i: &[u8]) -> nom::IResult<&[u8], u8> {
+    byte!(b'0'..=b'9')(i)
+}
+
+fn hexadecimal(i: &[u8]) -> nom::IResult<&[u8], u8> {
+    byte!(b'0' ..= b'9' | b'a' ..= b'f' | b'A' ..= b'F')(i)
+}
+
+// ========================================
+// ======== characters and strings ========
+// ========================================
+
+fn escape2char(c: char) -> CChar {
+    CChar::Char(match c {
+        'a' => '\x07',
+        'b' => '\x08',
+        'f' => '\x0c',
+        'n' => '\n',
+        'r' => '\r',
+        't' => '\t',
+        'v' => '\x0b',
+        _ => unreachable!("invalid escape {}", c),
+    })
+}
+
+fn c_raw_escape(n: Vec<u8>, radix: u32) -> Option<CChar> {
+    str::from_utf8(&n)
+        .ok()
+        .and_then(|i| u64::from_str_radix(i, radix).ok())
+        .map(|i| match i {
+            0..=0x7f => CChar::Char(i as u8 as char),
+            _ => CChar::Raw(i),
+        })
+}
+
+fn c_unicode_escape(n: Vec<u8>) -> Option<CChar> {
+    str::from_utf8(&n)
+        .ok()
+        .and_then(|i| u32::from_str_radix(i, 16).ok())
+        .and_then(char::from_u32)
+        .map(CChar::Char)
+}
+
+fn escaped_char(i: &[u8]) -> nom::IResult<&[u8], CChar> {
+    preceded(
+        char('\\'),
+        alt((
+            map(one_of(r#"'"?\"#), CChar::Char),
+            map(one_of("abfnrtv"), escape2char),
+            map_opt(many_m_n(1, 3, octal), |v| c_raw_escape(v, 8)),
+            map_opt(preceded(char('x'), many1(hexadecimal)), |v| {
+                c_raw_escape(v, 16)
+            }),
+            map_opt(
+                preceded(char('u'), many_m_n(4, 4, hexadecimal)),
+                c_unicode_escape,
+            ),
+            map_opt(
+                preceded(char('U'), many_m_n(8, 8, hexadecimal)),
+                c_unicode_escape,
+            ),
+        )),
+    )(i)
+}
+
+fn c_width_prefix(i: &[u8]) -> nom::IResult<&[u8], &[u8]> {
+    alt((tag("u8"), tag("u"), tag("U"), tag("L")))(i)
+}
+
+fn c_char(i: &[u8]) -> nom::IResult<&[u8], CChar> {
+    delimited(
+        terminated(opt(c_width_prefix), char('\'')),
+        alt((
+            escaped_char,
+            map(byte!(0 ..= 91 /* \=92 */ | 93 ..= 255), CChar::from),
+        )),
+        char('\''),
+    )(i)
+}
+
+fn c_string(i: &[u8]) -> nom::IResult<&[u8], Vec<u8>> {
+    delimited(
+        alt((preceded(c_width_prefix, char('"')), char('"'))),
+        fold_many0(
+            alt((
+                map(escaped_char, |c: CChar| c.into()),
+                map(is_not([b'\\', b'"']), |c: &[u8]| c.into()),
+            )),
+            Vec::new,
+            |mut v: Vec<u8>, res: Vec<u8>| {
+                v.extend_from_slice(&res);
+                v
+            },
+        ),
+        char('"'),
+    )(i)
+}
+
+// ================================
+// ======== parse integers ========
+// ================================
+
+fn c_int_radix(n: Vec<u8>, radix: u32) -> Option<u64> {
+    str::from_utf8(&n)
+        .ok()
+        .and_then(|i| u64::from_str_radix(i, radix).ok())
+}
+
+fn take_ul(input: &[u8]) -> IResult<&[u8], &[u8]> {
+    let r = input.split_at_position(|c| c != b'u' && c != b'U' && c != b'l' && c != b'L');
+    match r {
+        Err(Err::Incomplete(_)) => Ok((&input[input.len()..], input)),
+        res => res,
+    }
+}
+
+fn c_int(i: &[u8]) -> nom::IResult<&[u8], i64> {
+    map(
+        terminated(
+            alt((
+                map_opt(preceded(tag("0x"), many1(complete(hexadecimal))), |v| {
+                    c_int_radix(v, 16)
+                }),
+                map_opt(preceded(tag("0X"), many1(complete(hexadecimal))), |v| {
+                    c_int_radix(v, 16)
+                }),
+                map_opt(preceded(tag("0b"), many1(complete(binary))), |v| {
+                    c_int_radix(v, 2)
+                }),
+                map_opt(preceded(tag("0B"), many1(complete(binary))), |v| {
+                    c_int_radix(v, 2)
+                }),
+                map_opt(preceded(char('0'), many1(complete(octal))), |v| {
+                    c_int_radix(v, 8)
+                }),
+                map_opt(many1(complete(decimal)), |v| c_int_radix(v, 10)),
+                |input| Err(crate::nom::Err::Error(nom::error::Error::new(input, crate::nom::ErrorKind::Fix))),
+            )),
+            opt(take_ul),
+        ),
+        |i| i as i64,
+    )(i)
+}
+
+// ==============================
+// ======== parse floats ========
+// ==============================
+
+fn float_width(i: &[u8]) -> nom::IResult<&[u8], u8> {
+    nom::combinator::complete(byte!(b'f' | b'l' | b'F' | b'L'))(i)
+}
+
+fn float_exp(i: &[u8]) -> nom::IResult<&[u8], (Option<u8>, Vec<u8>)> {
+    preceded(
+        byte!(b'e' | b'E'),
+        pair(opt(byte!(b'-' | b'+')), many1(complete(decimal))),
+    )(i)
+}
+
+fn c_float(i: &[u8]) -> nom::IResult<&[u8], f64> {
+    map_opt(
+        alt((
+            terminated(
+                recognize(tuple((
+                    many1(complete(decimal)),
+                    byte!(b'.'),
+                    many0(complete(decimal)),
+                ))),
+                opt(float_width),
+            ),
+            terminated(
+                recognize(tuple((
+                    many0(complete(decimal)),
+                    byte!(b'.'),
+                    many1(complete(decimal)),
+                ))),
+                opt(float_width),
+            ),
+            terminated(
+                recognize(tuple((
+                    many0(complete(decimal)),
+                    opt(byte!(b'.')),
+                    many1(complete(decimal)),
+                    float_exp,
+                ))),
+                opt(float_width),
+            ),
+            terminated(
+                recognize(tuple((
+                    many1(complete(decimal)),
+                    opt(byte!(b'.')),
+                    many0(complete(decimal)),
+                    float_exp,
+                ))),
+                opt(float_width),
+            ),
+            terminated(recognize(many1(complete(decimal))), float_width),
+        )),
+        |v| str::from_utf8(v).ok().and_then(|i| f64::from_str(i).ok()),
+    )(i)
+}
+
+// ================================
+// ======== main interface ========
+// ================================
+
+fn one_literal(input: &[u8]) -> nom::IResult<&[u8], EvalResult, crate::Error<&[u8]>> {
+    alt((
+        map(full(c_char), EvalResult::Char),
+        map(full(c_int), |i| EvalResult::Int(::std::num::Wrapping(i))),
+        map(full(c_float), EvalResult::Float),
+        map(full(c_string), EvalResult::Str),
+    ))(input)
+    .to_cexpr_result()
+}
+
+/// Parse a C literal.
+///
+/// The input must contain exactly the representation of a single literal
+/// token, and in particular no whitespace or sign prefixes.
+pub fn parse(input: &[u8]) -> IResult<&[u8], EvalResult, crate::Error<&[u8]>> {
+    crate::assert_full_parse(one_literal(input))
+}
diff --git a/third_party/rust/cexpr/src/token.rs b/third_party/rust/cexpr/src/token.rs
new file mode 100644
index 0000000000..dbc5949cd4
--- /dev/null
+++ b/third_party/rust/cexpr/src/token.rs
@@ -0,0 +1,44 @@
+// (C) Copyright 2016 Jethro G. Beekman
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//! Representation of a C token
+//!
+//! This is designed to map onto a libclang CXToken.
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[allow(missing_docs)]
+pub enum Kind {
+    Punctuation,
+    Keyword,
+    Identifier,
+    Literal,
+    Comment,
+}
+
+/// A single token in a C expression.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Token {
+    /// The type of this token.
+    pub kind: Kind,
+    /// The bytes that make up the token.
+    pub raw: Box<[u8]>,
+}
+
+impl<'a> From<(Kind, &'a [u8])> for Token {
+    fn from((kind, value): (Kind, &'a [u8])) -> Token {
+        Token {
+            kind,
+            raw: value.to_owned().into_boxed_slice(),
+        }
+    }
+}
+
+/// Remove all comment tokens from a vector of tokens
+pub fn remove_comments(v: &mut Vec<Token>) -> &mut Vec<Token> {
+    v.retain(|t| t.kind != Kind::Comment);
+    v
+}
diff --git a/third_party/rust/cexpr/tests/clang.rs b/third_party/rust/cexpr/tests/clang.rs
new file mode 100644
index 0000000000..b2484f0778
--- /dev/null
+++ b/third_party/rust/cexpr/tests/clang.rs
@@ -0,0 +1,339 @@
+// (C) Copyright 2016 Jethro G. Beekman
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+extern crate cexpr;
+extern crate clang_sys;
+
+use std::collections::HashMap;
+use std::io::Write;
+use std::str::{self, FromStr};
+use std::{char, ffi, mem, ptr, slice};
+
+use cexpr::assert_full_parse;
+use cexpr::expr::{fn_macro_declaration, EvalResult, IdentifierParser};
+use cexpr::literal::CChar;
+use cexpr::token::Token;
+use clang_sys::*;
+
+// main testing routine
+fn test_definition(
+    ident: Vec<u8>,
+    tokens: &[Token],
+    idents: &mut HashMap<Vec<u8>, EvalResult>,
+) -> bool {
+    fn bytes_to_int(value: &[u8]) -> Option<EvalResult> {
+        str::from_utf8(value)
+            .ok()
+            .map(|s| s.replace("n", "-"))
+            .map(|s| s.replace("_", ""))
+            .and_then(|v| i64::from_str(&v).ok())
+            .map(::std::num::Wrapping)
+            .map(Int)
+    }
+
+    use cexpr::expr::EvalResult::*;
+
+    let display_name = String::from_utf8_lossy(&ident).into_owned();
+
+    let functional;
+    let test = {
+        // Split name such as Str_test_string into (Str,test_string)
+        let pos = ident
+            .iter()
+            .position(|c| *c == b'_')
+            .expect(&format!("Invalid definition in testcase: {}", display_name));
+        let mut expected = &ident[..pos];
+        let mut value = &ident[(pos + 1)..];
+
+        functional = expected == b"Fn";
+
+        if functional {
+            let ident = value;
+            let pos = ident
+                .iter()
+                .position(|c| *c == b'_')
+                .expect(&format!("Invalid definition in testcase: {}", display_name));
+            expected = &ident[..pos];
+            value = &ident[(pos + 1)..];
+        }
+
+        if expected == b"Str" {
+            let mut splits = value.split(|c| *c == b'U');
+            let mut s = Vec::with_capacity(value.len());
+            s.extend_from_slice(splits.next().unwrap());
+            for split in splits {
+                let (chr, rest) = split.split_at(6);
+                let chr = u32::from_str_radix(str::from_utf8(chr).unwrap(), 16).unwrap();
+                write!(s, "{}", char::from_u32(chr).unwrap()).unwrap();
+                s.extend_from_slice(rest);
+            }
+            Some(Str(s))
+        } else if expected == b"Int" {
+            bytes_to_int(value)
+        } else if expected == b"Float" {
+            str::from_utf8(value)
+                .ok()
+                .map(|s| s.replace("n", "-").replace("p", "."))
+                .and_then(|v| f64::from_str(&v).ok())
+                .map(Float)
+        } else if expected == b"CharRaw" {
+            str::from_utf8(value)
+                .ok()
+                .and_then(|v| u64::from_str(v).ok())
+                .map(CChar::Raw)
+                .map(Char)
+        } else if expected == b"CharChar" {
+            str::from_utf8(value)
+                .ok()
+                .and_then(|v| u32::from_str(v).ok())
+                .and_then(char::from_u32)
+                .map(CChar::Char)
+                .map(Char)
+        } else {
+            Some(Invalid)
+        }
+        .expect(&format!("Invalid definition in testcase: {}", display_name))
+    };
+
+    let result = if functional {
+        let mut fnidents;
+        let expr_tokens;
+        match fn_macro_declaration(&tokens) {
+            Ok((rest, (_, args))) => {
+                fnidents = idents.clone();
+                expr_tokens = rest;
+                for arg in args {
+                    let val = match test {
+                        Int(_) => bytes_to_int(&arg),
+                        Str(_) => Some(Str(arg.to_owned())),
+                        _ => unimplemented!(),
+                    }
+                    .expect(&format!(
+                        "Invalid argument in functional macro testcase: {}",
+                        display_name
+                    ));
+                    fnidents.insert(arg.to_owned(), val);
+                }
+            }
+            e => {
+                println!(
+                    "Failed test for {}, unable to parse functional macro declaration: {:?}",
+                    display_name, e
+                );
+                return false;
+            }
+        }
+        assert_full_parse(IdentifierParser::new(&fnidents).expr(&expr_tokens))
+    } else {
+        IdentifierParser::new(idents)
+            .macro_definition(&tokens)
+            .map(|(i, (_, val))| (i, val))
+    };
+
+    match result {
+        Ok((_, val)) => {
+            if val == test {
+                if let Some(_) = idents.insert(ident, val) {
+                    panic!("Duplicate definition for testcase: {}", display_name);
+                }
+                true
+            } else {
+                println!(
+                    "Failed test for {}, expected {:?}, got {:?}",
+                    display_name, test, val
+                );
+                false
+            }
+        }
+        e => {
+            if test == Invalid {
+                true
+            } else {
+                println!(
+                    "Failed test for {}, expected {:?}, got {:?}",
+                    display_name, test, e
+                );
+                false
+            }
+        }
+    }
+}
+
+// support code for the clang lexer
+unsafe fn clang_str_to_vec(s: CXString) -> Vec<u8> {
+    let vec = ffi::CStr::from_ptr(clang_getCString(s))
+        .to_bytes()
+        .to_owned();
+    clang_disposeString(s);
+    vec
+}
+
+#[allow(non_upper_case_globals)]
+unsafe fn token_clang_to_cexpr(tu: CXTranslationUnit, orig: &CXToken) -> Token {
+    Token {
+        kind: match clang_getTokenKind(*orig) {
+            CXToken_Comment => cexpr::token::Kind::Comment,
+            CXToken_Identifier => cexpr::token::Kind::Identifier,
+            CXToken_Keyword => cexpr::token::Kind::Keyword,
+            CXToken_Literal => cexpr::token::Kind::Literal,
+            CXToken_Punctuation => cexpr::token::Kind::Punctuation,
+            _ => panic!("invalid token kind: {:?}", *orig),
+        },
+        raw: clang_str_to_vec(clang_getTokenSpelling(tu, *orig)).into_boxed_slice(),
+    }
+}
+
+extern "C" fn visit_children_thunk<F>(
+    cur: CXCursor,
+    parent: CXCursor,
+    closure: CXClientData,
+) -> CXChildVisitResult
+where
+    F: FnMut(CXCursor, CXCursor) -> CXChildVisitResult,
+{
+    unsafe { (&mut *(closure as *mut F))(cur, parent) }
+}
+
+unsafe fn visit_children<F>(cursor: CXCursor, mut f: F)
+where
+    F: FnMut(CXCursor, CXCursor) -> CXChildVisitResult,
+{
+    clang_visitChildren(
+        cursor,
+        visit_children_thunk::<F> as _,
+        &mut f as *mut F as CXClientData,
+    );
+}
+
+unsafe fn location_in_scope(r: CXSourceRange) -> bool {
+    let start = clang_getRangeStart(r);
+    let mut file = ptr::null_mut();
+    clang_getSpellingLocation(
+        start,
+        &mut file,
+        ptr::null_mut(),
+        ptr::null_mut(),
+        ptr::null_mut(),
+    );
+    clang_Location_isFromMainFile(start) != 0
+        && clang_Location_isInSystemHeader(start) == 0
+        && file != ptr::null_mut()
+}
+
+/// tokenize_range_adjust can be used to work around LLVM bug 9069
+/// https://bugs.llvm.org//show_bug.cgi?id=9069
+fn file_visit_macros<F: FnMut(Vec<u8>, Vec<Token>)>(
+    file: &str,
+    tokenize_range_adjust: bool,
+    mut visitor: F,
+) {
+    unsafe {
+        let tu = {
+            let index = clang_createIndex(true as _, false as _);
+            let cfile = ffi::CString::new(file).unwrap();
+            let mut tu = mem::MaybeUninit::uninit();
+            assert!(
+                clang_parseTranslationUnit2(
+                    index,
+                    cfile.as_ptr(),
+                    [b"-std=c11\0".as_ptr() as *const ::std::os::raw::c_char].as_ptr(),
+                    1,
+                    ptr::null_mut(),
+                    0,
+                    CXTranslationUnit_DetailedPreprocessingRecord,
+                    &mut *tu.as_mut_ptr()
+                ) == CXError_Success,
+                "Failure reading test case {}",
+                file
+            );
+            tu.assume_init()
+        };
+        visit_children(clang_getTranslationUnitCursor(tu), |cur, _parent| {
+            if cur.kind == CXCursor_MacroDefinition {
+                let mut range = clang_getCursorExtent(cur);
+                if !location_in_scope(range) {
+                    return CXChildVisit_Continue;
+                }
+                range.end_int_data -= if tokenize_range_adjust { 1 } else { 0 };
+                let mut token_ptr = ptr::null_mut();
+                let mut num = 0;
+                clang_tokenize(tu, range, &mut token_ptr, &mut num);
+                if token_ptr != ptr::null_mut() {
+                    let tokens = slice::from_raw_parts(token_ptr, num as usize);
+                    let tokens: Vec<_> = tokens
+                        .iter()
+                        .filter_map(|t| {
+                            if clang_getTokenKind(*t) != CXToken_Comment {
+                                Some(token_clang_to_cexpr(tu, t))
+                            } else {
+                                None
+                            }
+                        })
+                        .collect();
+                    clang_disposeTokens(tu, token_ptr, num);
+                    visitor(clang_str_to_vec(clang_getCursorSpelling(cur)), tokens)
+                }
+            }
+            CXChildVisit_Continue
+        });
+        clang_disposeTranslationUnit(tu);
+    };
+}
+
+fn test_file(file: &str) -> bool {
+    let mut idents = HashMap::new();
+    let mut all_succeeded = true;
+    file_visit_macros(file, fix_bug_9069(), |ident, tokens| {
+        all_succeeded &= test_definition(ident, &tokens, &mut idents)
+    });
+    all_succeeded
+}
+
+fn fix_bug_9069() -> bool {
+    fn check_bug_9069() -> bool {
+        let mut token_sets = vec![];
+        file_visit_macros(
+            "tests/input/test_llvm_bug_9069.h",
+            false,
+            |ident, tokens| {
+                assert_eq!(&ident, b"A");
+                token_sets.push(tokens);
+            },
+        );
+        assert_eq!(token_sets.len(), 2);
+        token_sets[0] != token_sets[1]
+    }
+
+    use std::sync::atomic::{AtomicBool, Ordering};
+    use std::sync::Once;
+
+    static CHECK_FIX: Once = Once::new();
+    static FIX: AtomicBool = AtomicBool::new(false);
+
+    CHECK_FIX.call_once(|| FIX.store(check_bug_9069(), Ordering::SeqCst));
+
+    FIX.load(Ordering::SeqCst)
+}
+
+macro_rules! test_file {
+    ($f:ident) => {
+        #[test]
+        fn $f() {
+            assert!(
+                test_file(concat!("tests/input/", stringify!($f), ".h")),
+                "test_file"
+            )
+        }
+    };
+}
+
+test_file!(floats);
+test_file!(chars);
+test_file!(strings);
+test_file!(int_signed);
+test_file!(int_unsigned);
+test_file!(fail);
diff --git a/third_party/rust/cexpr/tests/input/chars.h b/third_party/rust/cexpr/tests/input/chars.h
new file mode 100644
index 0000000000..45351d3259
--- /dev/null
+++ b/third_party/rust/cexpr/tests/input/chars.h
@@ -0,0 +1,3 @@
+#define CharChar_65 'A'
+#define CharChar_127849 '\U0001f369' // 🍩
+#define CharRaw_255 U'\xff'
diff --git a/third_party/rust/cexpr/tests/input/fail.h b/third_party/rust/cexpr/tests/input/fail.h
new file mode 100644
index 0000000000..fd416bc7cb
--- /dev/null
+++ b/third_party/rust/cexpr/tests/input/fail.h
@@ -0,0 +1,9 @@
+#define FAIL_function_like(x) 3
+#define FAIL_empty
+#define FAIL_invalid_for_radix 0b2
+#define FAIL_shift_by_float 3<<1f
+#define FAIL_unknown_identifier UNKNOWN
+#define Int_0 0
+#define Str_str "str"
+#define FAIL_concat_integer "test" Str_str Int_0
+#define FAIL_too_large_int 18446744073709551616
diff --git a/third_party/rust/cexpr/tests/input/floats.h b/third_party/rust/cexpr/tests/input/floats.h
new file mode 100644
index 0000000000..61942cf41f
--- /dev/null
+++ b/third_party/rust/cexpr/tests/input/floats.h
@@ -0,0 +1,8 @@
+#define Float_0 0.
+#define Float_1 1f
+#define Float_p1 .1
+#define Float_2 2.0
+#define Float_1000 1e3
+#define Float_2000 2e+3
+#define Float_p001 1e-3
+#define Float_80 10.0*(1<<3)
diff --git a/third_party/rust/cexpr/tests/input/int_signed.h b/third_party/rust/cexpr/tests/input/int_signed.h
new file mode 100644
index 0000000000..65854a63e3
--- /dev/null
+++ b/third_party/rust/cexpr/tests/input/int_signed.h
@@ -0,0 +1,3 @@
+#define Int_n3 -(-(-3))
+#define Int_n5 -3-2
+#define Int_n9223372036854775808 -9223372036854775808
diff --git a/third_party/rust/cexpr/tests/input/int_unsigned.h b/third_party/rust/cexpr/tests/input/int_unsigned.h
new file mode 100644
index 0000000000..6663dda3d6
--- /dev/null
+++ b/third_party/rust/cexpr/tests/input/int_unsigned.h
@@ -0,0 +1,29 @@
+#define Int_456 456
+#define Int_0 0
+#define Int_1 0b1
+#define Int_2 0x2
+#define Int_3 3L
+#define Int_4 0X4
+#define Int_5 0B101
+#define Int_63 077
+#define Int_123 123
+#define Int_124 124u
+#define Int_125 125uL
+#define Int_126 126LuL
+#define Int_16 (((1)<<4ULL))/*comment*/ 
+#define Int_13 1|8^6&2<<1
+
+#define Int_47 32|15
+#define Int_38 (32|15)^9
+#define Int_6 ((32|15)^9)&7
+#define Int_12 (((32|15)^9)&7)<<1
+#define Int_17 ((((32|15)^9)&7)<<1)+5
+#define Int_15 (((((32|15)^9)&7)<<1)+5)-2
+#define Int_60 ((((((32|15)^9)&7)<<1)+5)-2)*4
+#define Int_30 (((((((32|15)^9)&7)<<1)+5)-2)*4)/2
+#define Int_39 32|15^9&7<<1+5-2*4/2
+
+#define Int_n1 18446744073709551615 /*2^64-1*/
+#define Int_n9223372036854775808 9223372036854775808
+
+#define Fn_Int_9(_3) _3*3
diff --git a/third_party/rust/cexpr/tests/input/strings.h b/third_party/rust/cexpr/tests/input/strings.h
new file mode 100644
index 0000000000..d01d409cbf
--- /dev/null
+++ b/third_party/rust/cexpr/tests/input/strings.h
@@ -0,0 +1,17 @@
+#define Str_ ""
+#define Str_str "str"
+#define Str_unicode u"unicode"
+#define Str_long L"long"
+#define Str_concat u"con" L"cat"
+#define Str_concat_parens ("concat" U"_parens")
+#define Str_concat_identifier (Str_concat L"_identifier")
+#define Str_hex_escape_all "\x68\x65\x78\x5f\x65\x73\x63\x61\x70\x65\x5f\x61\x6c\x6c"
+#define Str_hex_escape_hex "h\x65x_\x65s\x63\x61p\x65_h\x65x"
+#define Str_quote_U000022_escape "quote_\"_escape"
+#define Str_Fly_away_in_my_space_U01F680_You_no_need_put_U01F4B5_in_my_pocket \
+	u8"Fly_away_in_my_space_🚀_You_no_need_put_💵_in_my_pocket"
+#define Fn_Str_no_args() "no_args"
+#define Fn_Str_no_args_concat() "no_args_" Str_concat
+#define Fn_Str_prepend_arg(arg) "prepend_" arg
+#define Fn_Str_two_args(two, args) two "_" args
+#define Fn_Str_three_args(three, _, args) three _ args
diff --git a/third_party/rust/cexpr/tests/input/test_llvm_bug_9069.h b/third_party/rust/cexpr/tests/input/test_llvm_bug_9069.h
new file mode 100644
index 0000000000..a92374efee
--- /dev/null
+++ b/third_party/rust/cexpr/tests/input/test_llvm_bug_9069.h
@@ -0,0 +1,4 @@
+// The following two definitions should yield the same list of tokens.
+// If https://bugs.llvm.org//show_bug.cgi?id=9069 is not fixed, they don't.
+#define A 1
+#define A 1