Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 1942 insertions, 0 deletions

diff --git a/third_party/rust/wast/src/core/expr.rs b/third_party/rust/wast/src/core/expr.rs
new file mode 100644
index 0000000000..489ac205af
--- /dev/null
+++ b/third_party/rust/wast/src/core/expr.rs
@@ -0,0 +1,1942 @@
+use crate::core::*;
+use crate::encode::Encode;
+use crate::kw;
+use crate::parser::{Cursor, Parse, Parser, Result};
+use crate::token::*;
+use std::mem;
+
+/// An expression, or a list of instructions, in the WebAssembly text format.
+///
+/// This expression type will parse s-expression-folded instructions into a flat
+/// list of instructions for emission later on. The implicit `end` instruction
+/// at the end of an expression is not included in the `instrs` field.
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub struct Expression<'a> {
+    pub instrs: Box<[Instruction<'a>]>,
+}
+
+impl<'a> Parse<'a> for Expression<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut exprs = ExpressionParser::default();
+        exprs.parse(parser)?;
+        Ok(Expression {
+            instrs: exprs.instrs.into(),
+        })
+    }
+}
+
+impl<'a> Expression<'a> {
+    /// Parse an expression formed from a single folded instruction.
+    ///
+    /// Attempts to parse an expression formed from a single folded instruction.
+    ///
+    /// This method will mutate the state of `parser` after attempting to parse
+    /// the expression. If an error happens then it is likely fatal and
+    /// there is no guarantee of how many tokens have been consumed from
+    /// `parser`.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error if the expression could not be
+    /// parsed. Note that creating an [`crate::Error`] is not exactly a cheap
+    /// operation, so [`crate::Error`] is typically fatal and propagated all the
+    /// way back to the top parse call site.
+    pub fn parse_folded_instruction(parser: Parser<'a>) -> Result<Self> {
+        let mut exprs = ExpressionParser::default();
+        exprs.parse_folded_instruction(parser)?;
+        Ok(Expression {
+            instrs: exprs.instrs.into(),
+        })
+    }
+}
+
+/// Helper struct used to parse an `Expression` with helper methods and such.
+///
+/// The primary purpose of this is to avoid defining expression parsing as a
+/// call-thread-stack recursive function. Since we're parsing user input that
+/// runs the risk of blowing the call stack, so we want to be sure to use a heap
+/// stack structure wherever possible.
+#[derive(Default)]
+struct ExpressionParser<'a> {
+    /// The flat list of instructions that we've parsed so far, and will
+    /// eventually become the final `Expression`.
+    instrs: Vec<Instruction<'a>>,
+
+    /// Descriptor of all our nested s-expr blocks. This only happens when
+    /// instructions themselves are nested.
+    stack: Vec<Level<'a>>,
+}
+
+enum Paren {
+    None,
+    Left,
+    Right,
+}
+
+/// A "kind" of nested block that we can be parsing inside of.
+enum Level<'a> {
+    /// This is a normal `block` or `loop` or similar, where the instruction
+    /// payload here is pushed when the block is exited.
+    EndWith(Instruction<'a>),
+
+    /// This is a pretty special variant which means that we're parsing an `if`
+    /// statement, and the state of the `if` parsing is tracked internally in
+    /// the payload.
+    If(If<'a>),
+
+    /// This means we're either parsing inside of `(then ...)` or `(else ...)`
+    /// which don't correspond to terminating instructions, we're just in a
+    /// nested block.
+    IfArm,
+}
+
+/// Possible states of "what is currently being parsed?" in an `if` expression.
+enum If<'a> {
+    /// Only the `if` instructoin has been parsed, next thing to parse is the
+    /// clause, if any, of the `if` instruction.
+    ///
+    /// This parse ends when `(then ...)` is encountered.
+    Clause(Instruction<'a>),
+    /// Currently parsing the `then` block, and afterwards a closing paren is
+    /// required or an `(else ...)` expression.
+    Then,
+    /// Parsing the `else` expression, nothing can come after.
+    Else,
+}
+
+impl<'a> ExpressionParser<'a> {
+    fn parse(&mut self, parser: Parser<'a>) -> Result<()> {
+        // Here we parse instructions in a loop, and we do not recursively
+        // invoke this parse function to avoid blowing the stack on
+        // deeply-recursive parses.
+        //
+        // Our loop generally only finishes once there's no more input left int
+        // the `parser`. If there's some unclosed delimiters though (on our
+        // `stack`), then we also keep parsing to generate error messages if
+        // there's no input left.
+        while !parser.is_empty() || !self.stack.is_empty() {
+            // As a small ease-of-life adjustment here, if we're parsing inside
+            // of an `if block then we require that all sub-components are
+            // s-expressions surrounded by `(` and `)`, so verify that here.
+            if let Some(Level::If(_)) = self.stack.last() {
+                if !parser.is_empty() && !parser.peek::<LParen>()? {
+                    return Err(parser.error("expected `(`"));
+                }
+            }
+
+            match self.paren(parser)? {
+                // No parenthesis seen? Then we just parse the next instruction
+                // and move on.
+                Paren::None => self.instrs.push(parser.parse()?),
+
+                // If we see a left-parenthesis then things are a little
+                // special. We handle block-like instructions specially
+                // (`block`, `loop`, and `if`), and otherwise all other
+                // instructions simply get appended once we reach the end of the
+                // s-expression.
+                //
+                // In all cases here we push something onto the `stack` to get
+                // popped when the `)` character is seen.
+                Paren::Left => {
+                    // First up is handling `if` parsing, which is funky in a
+                    // whole bunch of ways. See the method internally for more
+                    // information.
+                    if self.handle_if_lparen(parser)? {
+                        continue;
+                    }
+                    match parser.parse()? {
+                        // If block/loop show up then we just need to be sure to
+                        // push an `end` instruction whenever the `)` token is
+                        // seen
+                        i @ Instruction::Block(_)
+                        | i @ Instruction::Loop(_)
+                        | i @ Instruction::Let(_)
+                        | i @ Instruction::TryTable(_) => {
+                            self.instrs.push(i);
+                            self.stack.push(Level::EndWith(Instruction::End(None)));
+                        }
+
+                        // Parsing an `if` instruction is super tricky, so we
+                        // push an `If` scope and we let all our scope-based
+                        // parsing handle the remaining items.
+                        i @ Instruction::If(_) => {
+                            self.stack.push(Level::If(If::Clause(i)));
+                        }
+
+                        // Anything else means that we're parsing a nested form
+                        // such as `(i32.add ...)` which means that the
+                        // instruction we parsed will be coming at the end.
+                        other => self.stack.push(Level::EndWith(other)),
+                    }
+                }
+
+                // If we registered a `)` token as being seen, then we're
+                // guaranteed there's an item in the `stack` stack for us to
+                // pop. We peel that off and take a look at what it says to do.
+                Paren::Right => match self.stack.pop().unwrap() {
+                    Level::EndWith(i) => self.instrs.push(i),
+                    Level::IfArm => {}
+
+                    // If an `if` statement hasn't parsed the clause or `then`
+                    // block, then that's an error because there weren't enough
+                    // items in the `if` statement. Otherwise we're just careful
+                    // to terminate with an `end` instruction.
+                    Level::If(If::Clause(_)) => {
+                        return Err(parser.error("previous `if` had no `then`"));
+                    }
+                    Level::If(_) => {
+                        self.instrs.push(Instruction::End(None));
+                    }
+                },
+            }
+        }
+
+        Ok(())
+    }
+
+    fn parse_folded_instruction(&mut self, parser: Parser<'a>) -> Result<()> {
+        let mut done = false;
+        while !done {
+            match self.paren(parser)? {
+                Paren::Left => {
+                    self.stack.push(Level::EndWith(parser.parse()?));
+                }
+                Paren::Right => {
+                    let top_instr = match self.stack.pop().unwrap() {
+                        Level::EndWith(i) => i,
+                        _ => panic!("unknown level type"),
+                    };
+                    self.instrs.push(top_instr);
+                    if self.stack.is_empty() {
+                        done = true;
+                    }
+                }
+                Paren::None => {
+                    return Err(parser.error("expected to continue a folded instruction"))
+                }
+            }
+        }
+        Ok(())
+    }
+
+    /// Parses either `(`, `)`, or nothing.
+    fn paren(&self, parser: Parser<'a>) -> Result<Paren> {
+        parser.step(|cursor| {
+            Ok(match cursor.lparen()? {
+                Some(rest) => (Paren::Left, rest),
+                None if self.stack.is_empty() => (Paren::None, cursor),
+                None => match cursor.rparen()? {
+                    Some(rest) => (Paren::Right, rest),
+                    None => (Paren::None, cursor),
+                },
+            })
+        })
+    }
+
+    /// State transitions with parsing an `if` statement.
+    ///
+    /// The syntactical form of an `if` stament looks like:
+    ///
+    /// ```wat
+    /// (if ($clause)... (then $then) (else $else))
+    /// ```
+    ///
+    /// THis method is called after a `(` is parsed within the `(if ...` block.
+    /// This determines what to do next.
+    ///
+    /// Returns `true` if the rest of the arm above should be skipped, or
+    /// `false` if we should parse the next item as an instruction (because we
+    /// didn't handle the lparen here).
+    fn handle_if_lparen(&mut self, parser: Parser<'a>) -> Result<bool> {
+        // Only execute the code below if there's an `If` listed last.
+        let i = match self.stack.last_mut() {
+            Some(Level::If(i)) => i,
+            _ => return Ok(false),
+        };
+
+        match i {
+            // If the clause is still being parsed then interpret this `(` as a
+            // folded instruction unless it starts with `then`, in which case
+            // this transitions to the `Then` state and a new level has been
+            // reached.
+            If::Clause(if_instr) => {
+                if !parser.peek::<kw::then>()? {
+                    return Ok(false);
+                }
+                parser.parse::<kw::then>()?;
+                let instr = mem::replace(if_instr, Instruction::End(None));
+                self.instrs.push(instr);
+                *i = If::Then;
+                self.stack.push(Level::IfArm);
+                Ok(true)
+            }
+
+            // Previously we were parsing the `(then ...)` clause so this next
+            // `(` must be followed by `else`.
+            If::Then => {
+                parser.parse::<kw::r#else>()?;
+                self.instrs.push(Instruction::Else(None));
+                *i = If::Else;
+                self.stack.push(Level::IfArm);
+                Ok(true)
+            }
+
+            // If after a `(else ...` clause is parsed there's another `(` then
+            // that's not syntactically allowed.
+            If::Else => Err(parser.error("unexpected token: too many payloads inside of `(if)`")),
+        }
+    }
+}
+
+// TODO: document this obscenity
+macro_rules! instructions {
+    (pub enum Instruction<'a> {
+        $(
+            $(#[$doc:meta])*
+            $name:ident $(($($arg:tt)*))? : [$($binary:tt)*] : $instr:tt $( | $deprecated:tt )?,
+        )*
+    }) => (
+        /// A listing of all WebAssembly instructions that can be in a module
+        /// that this crate currently parses.
+        #[derive(Debug)]
+        #[allow(missing_docs)]
+        pub enum Instruction<'a> {
+            $(
+                $(#[$doc])*
+                $name $(( instructions!(@ty $($arg)*) ))?,
+            )*
+        }
+
+        #[allow(non_snake_case)]
+        impl<'a> Parse<'a> for Instruction<'a> {
+            fn parse(parser: Parser<'a>) -> Result<Self> {
+                $(
+                    fn $name<'a>(_parser: Parser<'a>) -> Result<Instruction<'a>> {
+                        Ok(Instruction::$name $((
+                            instructions!(@parse _parser $($arg)*)?
+                        ))?)
+                    }
+                )*
+                let parse_remainder = parser.step(|c| {
+                    let (kw, rest) = match c.keyword() ?{
+                        Some(pair) => pair,
+                        None => return Err(c.error("expected an instruction")),
+                    };
+                    match kw {
+                        $($instr $( | $deprecated )?=> Ok(($name as fn(_) -> _, rest)),)*
+                        _ => return Err(c.error("unknown operator or unexpected token")),
+                    }
+                })?;
+                parse_remainder(parser)
+            }
+        }
+
+        impl Encode for Instruction<'_> {
+            #[allow(non_snake_case)]
+            fn encode(&self, v: &mut Vec<u8>) {
+                match self {
+                    $(
+                        Instruction::$name $((instructions!(@first x $($arg)*)))? => {
+                            fn encode<'a>($(arg: &instructions!(@ty $($arg)*),)? v: &mut Vec<u8>) {
+                                instructions!(@encode v $($binary)*);
+                                $(<instructions!(@ty $($arg)*) as Encode>::encode(arg, v);)?
+                            }
+                            encode($( instructions!(@first x $($arg)*), )? v)
+                        }
+                    )*
+                }
+            }
+        }
+
+        impl<'a> Instruction<'a> {
+            /// Returns the associated [`MemArg`] if one is available for this
+            /// instruction.
+            #[allow(unused_variables, non_snake_case)]
+            pub fn memarg_mut(&mut self) -> Option<&mut MemArg<'a>> {
+                match self {
+                    $(
+                        Instruction::$name $((instructions!(@memarg_binding a $($arg)*)))? => {
+                            instructions!(@get_memarg a $($($arg)*)?)
+                        }
+                    )*
+                }
+            }
+        }
+    );
+
+    (@ty MemArg<$amt:tt>) => (MemArg<'a>);
+    (@ty LoadOrStoreLane<$amt:tt>) => (LoadOrStoreLane<'a>);
+    (@ty $other:ty) => ($other);
+
+    (@first $first:ident $($t:tt)*) => ($first);
+
+    (@parse $parser:ident MemArg<$amt:tt>) => (MemArg::parse($parser, $amt));
+    (@parse $parser:ident MemArg) => (compile_error!("must specify `MemArg` default"));
+    (@parse $parser:ident LoadOrStoreLane<$amt:tt>) => (LoadOrStoreLane::parse($parser, $amt));
+    (@parse $parser:ident LoadOrStoreLane) => (compile_error!("must specify `LoadOrStoreLane` default"));
+    (@parse $parser:ident $other:ty) => ($parser.parse::<$other>());
+
+    // simd opcodes prefixed with `0xfd` get a varuint32 encoding for their payload
+    (@encode $dst:ident 0xfd, $simd:tt) => ({
+        $dst.push(0xfd);
+        <u32 as Encode>::encode(&$simd, $dst);
+    });
+    (@encode $dst:ident $($bytes:tt)*) => ($dst.extend_from_slice(&[$($bytes)*]););
+
+    (@get_memarg $name:ident MemArg<$amt:tt>) => (Some($name));
+    (@get_memarg $name:ident LoadOrStoreLane<$amt:tt>) => (Some(&mut $name.memarg));
+    (@get_memarg $($other:tt)*) => (None);
+
+    (@memarg_binding $name:ident MemArg<$amt:tt>) => ($name);
+    (@memarg_binding $name:ident LoadOrStoreLane<$amt:tt>) => ($name);
+    (@memarg_binding $name:ident $other:ty) => (_);
+}
+
+instructions! {
+    pub enum Instruction<'a> {
+        Block(Box<BlockType<'a>>) : [0x02] : "block",
+        If(Box<BlockType<'a>>) : [0x04] : "if",
+        Else(Option<Id<'a>>) : [0x05] : "else",
+        Loop(Box<BlockType<'a>>) : [0x03] : "loop",
+        End(Option<Id<'a>>) : [0x0b] : "end",
+
+        Unreachable : [0x00] : "unreachable",
+        Nop : [0x01] : "nop",
+        Br(Index<'a>) : [0x0c] : "br",
+        BrIf(Index<'a>) : [0x0d] : "br_if",
+        BrTable(BrTableIndices<'a>) : [0x0e] : "br_table",
+        Return : [0x0f] : "return",
+        Call(Index<'a>) : [0x10] : "call",
+        CallIndirect(Box<CallIndirect<'a>>) : [0x11] : "call_indirect",
+
+        // tail-call proposal
+        ReturnCall(Index<'a>) : [0x12] : "return_call",
+        ReturnCallIndirect(Box<CallIndirect<'a>>) : [0x13] : "return_call_indirect",
+
+        // function-references proposal
+        CallRef(Index<'a>) : [0x14] : "call_ref",
+        ReturnCallRef(Index<'a>) : [0x15] : "return_call_ref",
+        FuncBind(FuncBindType<'a>) : [0x16] : "func.bind",
+        Let(LetType<'a>) : [0x17] : "let",
+
+        Drop : [0x1a] : "drop",
+        Select(SelectTypes<'a>) : [] : "select",
+        LocalGet(Index<'a>) : [0x20] : "local.get",
+        LocalSet(Index<'a>) : [0x21] : "local.set",
+        LocalTee(Index<'a>) : [0x22] : "local.tee",
+        GlobalGet(Index<'a>) : [0x23] : "global.get",
+        GlobalSet(Index<'a>) : [0x24] : "global.set",
+
+        TableGet(TableArg<'a>) : [0x25] : "table.get",
+        TableSet(TableArg<'a>) : [0x26] : "table.set",
+
+        I32Load(MemArg<4>) : [0x28] : "i32.load",
+        I64Load(MemArg<8>) : [0x29] : "i64.load",
+        F32Load(MemArg<4>) : [0x2a] : "f32.load",
+        F64Load(MemArg<8>) : [0x2b] : "f64.load",
+        I32Load8s(MemArg<1>) : [0x2c] : "i32.load8_s",
+        I32Load8u(MemArg<1>) : [0x2d] : "i32.load8_u",
+        I32Load16s(MemArg<2>) : [0x2e] : "i32.load16_s",
+        I32Load16u(MemArg<2>) : [0x2f] : "i32.load16_u",
+        I64Load8s(MemArg<1>) : [0x30] : "i64.load8_s",
+        I64Load8u(MemArg<1>) : [0x31] : "i64.load8_u",
+        I64Load16s(MemArg<2>) : [0x32] : "i64.load16_s",
+        I64Load16u(MemArg<2>) : [0x33] : "i64.load16_u",
+        I64Load32s(MemArg<4>) : [0x34] : "i64.load32_s",
+        I64Load32u(MemArg<4>) : [0x35] : "i64.load32_u",
+        I32Store(MemArg<4>) : [0x36] : "i32.store",
+        I64Store(MemArg<8>) : [0x37] : "i64.store",
+        F32Store(MemArg<4>) : [0x38] : "f32.store",
+        F64Store(MemArg<8>) : [0x39] : "f64.store",
+        I32Store8(MemArg<1>) : [0x3a] : "i32.store8",
+        I32Store16(MemArg<2>) : [0x3b] : "i32.store16",
+        I64Store8(MemArg<1>) : [0x3c] : "i64.store8",
+        I64Store16(MemArg<2>) : [0x3d] : "i64.store16",
+        I64Store32(MemArg<4>) : [0x3e] : "i64.store32",
+
+        // Lots of bulk memory proposal here as well
+        MemorySize(MemoryArg<'a>) : [0x3f] : "memory.size",
+        MemoryGrow(MemoryArg<'a>) : [0x40] : "memory.grow",
+        MemoryInit(MemoryInit<'a>) : [0xfc, 0x08] : "memory.init",
+        MemoryCopy(MemoryCopy<'a>) : [0xfc, 0x0a] : "memory.copy",
+        MemoryFill(MemoryArg<'a>) : [0xfc, 0x0b] : "memory.fill",
+        MemoryDiscard(MemoryArg<'a>) : [0xfc, 0x12] : "memory.discard",
+        DataDrop(Index<'a>) : [0xfc, 0x09] : "data.drop",
+        ElemDrop(Index<'a>) : [0xfc, 0x0d] : "elem.drop",
+        TableInit(TableInit<'a>) : [0xfc, 0x0c] : "table.init",
+        TableCopy(TableCopy<'a>) : [0xfc, 0x0e] : "table.copy",
+        TableFill(TableArg<'a>) : [0xfc, 0x11] : "table.fill",
+        TableSize(TableArg<'a>) : [0xfc, 0x10] : "table.size",
+        TableGrow(TableArg<'a>) : [0xfc, 0x0f] : "table.grow",
+
+        RefNull(HeapType<'a>) : [0xd0] : "ref.null",
+        RefIsNull : [0xd1] : "ref.is_null",
+        RefFunc(Index<'a>) : [0xd2] : "ref.func",
+
+        // function-references proposal
+        RefAsNonNull : [0xd4] : "ref.as_non_null",
+        BrOnNull(Index<'a>) : [0xd5] : "br_on_null",
+        BrOnNonNull(Index<'a>) : [0xd6] : "br_on_non_null",
+
+        // gc proposal: eqref
+        RefEq : [0xd3] : "ref.eq",
+
+        // gc proposal: struct
+        StructNew(Index<'a>) : [0xfb, 0x00] : "struct.new",
+        StructNewDefault(Index<'a>) : [0xfb, 0x01] : "struct.new_default",
+        StructGet(StructAccess<'a>) : [0xfb, 0x02] : "struct.get",
+        StructGetS(StructAccess<'a>) : [0xfb, 0x03] : "struct.get_s",
+        StructGetU(StructAccess<'a>) : [0xfb, 0x04] : "struct.get_u",
+        StructSet(StructAccess<'a>) : [0xfb, 0x05] : "struct.set",
+
+        // gc proposal: array
+        ArrayNew(Index<'a>) : [0xfb, 0x06] : "array.new",
+        ArrayNewDefault(Index<'a>) : [0xfb, 0x07] : "array.new_default",
+        ArrayNewFixed(ArrayNewFixed<'a>) : [0xfb, 0x08] : "array.new_fixed",
+        ArrayNewData(ArrayNewData<'a>) : [0xfb, 0x09] : "array.new_data",
+        ArrayNewElem(ArrayNewElem<'a>) : [0xfb, 0x0a] : "array.new_elem",
+        ArrayGet(Index<'a>) : [0xfb, 0x0b] : "array.get",
+        ArrayGetS(Index<'a>) : [0xfb, 0x0c] : "array.get_s",
+        ArrayGetU(Index<'a>) : [0xfb, 0x0d] : "array.get_u",
+        ArraySet(Index<'a>) : [0xfb, 0x0e] : "array.set",
+        ArrayLen : [0xfb, 0x0f] : "array.len",
+        ArrayFill(ArrayFill<'a>) : [0xfb, 0x10] : "array.fill",
+        ArrayCopy(ArrayCopy<'a>) : [0xfb, 0x11] : "array.copy",
+        ArrayInitData(ArrayInit<'a>) : [0xfb, 0x12] : "array.init_data",
+        ArrayInitElem(ArrayInit<'a>) : [0xfb, 0x13] : "array.init_elem",
+
+        // gc proposal, i31
+        RefI31 : [0xfb, 0x1c] : "ref.i31",
+        I31GetS : [0xfb, 0x1d] : "i31.get_s",
+        I31GetU : [0xfb, 0x1e] : "i31.get_u",
+
+        // gc proposal, concrete casting
+        RefTest(RefTest<'a>) : [] : "ref.test",
+        RefCast(RefCast<'a>) : [] : "ref.cast",
+        BrOnCast(Box<BrOnCast<'a>>) : [] : "br_on_cast",
+        BrOnCastFail(Box<BrOnCastFail<'a>>) : [] : "br_on_cast_fail",
+
+        // gc proposal extern/any coercion operations
+        AnyConvertExtern : [0xfb, 0x1a] : "any.convert_extern",
+        ExternConvertAny : [0xfb, 0x1b] : "extern.convert_any",
+
+        I32Const(i32) : [0x41] : "i32.const",
+        I64Const(i64) : [0x42] : "i64.const",
+        F32Const(Float32) : [0x43] : "f32.const",
+        F64Const(Float64) : [0x44] : "f64.const",
+
+        I32Clz : [0x67] : "i32.clz",
+        I32Ctz : [0x68] : "i32.ctz",
+        I32Popcnt : [0x69] : "i32.popcnt",
+        I32Add : [0x6a] : "i32.add",
+        I32Sub : [0x6b] : "i32.sub",
+        I32Mul : [0x6c] : "i32.mul",
+        I32DivS : [0x6d] : "i32.div_s",
+        I32DivU : [0x6e] : "i32.div_u",
+        I32RemS : [0x6f] : "i32.rem_s",
+        I32RemU : [0x70] : "i32.rem_u",
+        I32And : [0x71] : "i32.and",
+        I32Or : [0x72] : "i32.or",
+        I32Xor : [0x73] : "i32.xor",
+        I32Shl : [0x74] : "i32.shl",
+        I32ShrS : [0x75] : "i32.shr_s",
+        I32ShrU : [0x76] : "i32.shr_u",
+        I32Rotl : [0x77] : "i32.rotl",
+        I32Rotr : [0x78] : "i32.rotr",
+
+        I64Clz : [0x79] : "i64.clz",
+        I64Ctz : [0x7a] : "i64.ctz",
+        I64Popcnt : [0x7b] : "i64.popcnt",
+        I64Add : [0x7c] : "i64.add",
+        I64Sub : [0x7d] : "i64.sub",
+        I64Mul : [0x7e] : "i64.mul",
+        I64DivS : [0x7f] : "i64.div_s",
+        I64DivU : [0x80] : "i64.div_u",
+        I64RemS : [0x81] : "i64.rem_s",
+        I64RemU : [0x82] : "i64.rem_u",
+        I64And : [0x83] : "i64.and",
+        I64Or : [0x84] : "i64.or",
+        I64Xor : [0x85] : "i64.xor",
+        I64Shl : [0x86] : "i64.shl",
+        I64ShrS : [0x87] : "i64.shr_s",
+        I64ShrU : [0x88] : "i64.shr_u",
+        I64Rotl : [0x89] : "i64.rotl",
+        I64Rotr : [0x8a] : "i64.rotr",
+
+        F32Abs : [0x8b] : "f32.abs",
+        F32Neg : [0x8c] : "f32.neg",
+        F32Ceil : [0x8d] : "f32.ceil",
+        F32Floor : [0x8e] : "f32.floor",
+        F32Trunc : [0x8f] : "f32.trunc",
+        F32Nearest : [0x90] : "f32.nearest",
+        F32Sqrt : [0x91] : "f32.sqrt",
+        F32Add : [0x92] : "f32.add",
+        F32Sub : [0x93] : "f32.sub",
+        F32Mul : [0x94] : "f32.mul",
+        F32Div : [0x95] : "f32.div",
+        F32Min : [0x96] : "f32.min",
+        F32Max : [0x97] : "f32.max",
+        F32Copysign : [0x98] : "f32.copysign",
+
+        F64Abs : [0x99] : "f64.abs",
+        F64Neg : [0x9a] : "f64.neg",
+        F64Ceil : [0x9b] : "f64.ceil",
+        F64Floor : [0x9c] : "f64.floor",
+        F64Trunc : [0x9d] : "f64.trunc",
+        F64Nearest : [0x9e] : "f64.nearest",
+        F64Sqrt : [0x9f] : "f64.sqrt",
+        F64Add : [0xa0] : "f64.add",
+        F64Sub : [0xa1] : "f64.sub",
+        F64Mul : [0xa2] : "f64.mul",
+        F64Div : [0xa3] : "f64.div",
+        F64Min : [0xa4] : "f64.min",
+        F64Max : [0xa5] : "f64.max",
+        F64Copysign : [0xa6] : "f64.copysign",
+
+        I32Eqz : [0x45] : "i32.eqz",
+        I32Eq : [0x46] : "i32.eq",
+        I32Ne : [0x47] : "i32.ne",
+        I32LtS : [0x48] : "i32.lt_s",
+        I32LtU : [0x49] : "i32.lt_u",
+        I32GtS : [0x4a] : "i32.gt_s",
+        I32GtU : [0x4b] : "i32.gt_u",
+        I32LeS : [0x4c] : "i32.le_s",
+        I32LeU : [0x4d] : "i32.le_u",
+        I32GeS : [0x4e] : "i32.ge_s",
+        I32GeU : [0x4f] : "i32.ge_u",
+
+        I64Eqz : [0x50] : "i64.eqz",
+        I64Eq : [0x51] : "i64.eq",
+        I64Ne : [0x52] : "i64.ne",
+        I64LtS : [0x53] : "i64.lt_s",
+        I64LtU : [0x54] : "i64.lt_u",
+        I64GtS : [0x55] : "i64.gt_s",
+        I64GtU : [0x56] : "i64.gt_u",
+        I64LeS : [0x57] : "i64.le_s",
+        I64LeU : [0x58] : "i64.le_u",
+        I64GeS : [0x59] : "i64.ge_s",
+        I64GeU : [0x5a] : "i64.ge_u",
+
+        F32Eq : [0x5b] : "f32.eq",
+        F32Ne : [0x5c] : "f32.ne",
+        F32Lt : [0x5d] : "f32.lt",
+        F32Gt : [0x5e] : "f32.gt",
+        F32Le : [0x5f] : "f32.le",
+        F32Ge : [0x60] : "f32.ge",
+
+        F64Eq : [0x61] : "f64.eq",
+        F64Ne : [0x62] : "f64.ne",
+        F64Lt : [0x63] : "f64.lt",
+        F64Gt : [0x64] : "f64.gt",
+        F64Le : [0x65] : "f64.le",
+        F64Ge : [0x66] : "f64.ge",
+
+        I32WrapI64 : [0xa7] : "i32.wrap_i64",
+        I32TruncF32S : [0xa8] : "i32.trunc_f32_s",
+        I32TruncF32U : [0xa9] : "i32.trunc_f32_u",
+        I32TruncF64S : [0xaa] : "i32.trunc_f64_s",
+        I32TruncF64U : [0xab] : "i32.trunc_f64_u",
+        I64ExtendI32S : [0xac] : "i64.extend_i32_s",
+        I64ExtendI32U : [0xad] : "i64.extend_i32_u",
+        I64TruncF32S : [0xae] : "i64.trunc_f32_s",
+        I64TruncF32U : [0xaf] : "i64.trunc_f32_u",
+        I64TruncF64S : [0xb0] : "i64.trunc_f64_s",
+        I64TruncF64U : [0xb1] : "i64.trunc_f64_u",
+        F32ConvertI32S : [0xb2] : "f32.convert_i32_s",
+        F32ConvertI32U : [0xb3] : "f32.convert_i32_u",
+        F32ConvertI64S : [0xb4] : "f32.convert_i64_s",
+        F32ConvertI64U : [0xb5] : "f32.convert_i64_u",
+        F32DemoteF64 : [0xb6] : "f32.demote_f64",
+        F64ConvertI32S : [0xb7] : "f64.convert_i32_s",
+        F64ConvertI32U : [0xb8] : "f64.convert_i32_u",
+        F64ConvertI64S : [0xb9] : "f64.convert_i64_s",
+        F64ConvertI64U : [0xba] : "f64.convert_i64_u",
+        F64PromoteF32 : [0xbb] : "f64.promote_f32",
+        I32ReinterpretF32 : [0xbc] : "i32.reinterpret_f32",
+        I64ReinterpretF64 : [0xbd] : "i64.reinterpret_f64",
+        F32ReinterpretI32 : [0xbe] : "f32.reinterpret_i32",
+        F64ReinterpretI64 : [0xbf] : "f64.reinterpret_i64",
+
+        // non-trapping float to int
+        I32TruncSatF32S : [0xfc, 0x00] : "i32.trunc_sat_f32_s",
+        I32TruncSatF32U : [0xfc, 0x01] : "i32.trunc_sat_f32_u",
+        I32TruncSatF64S : [0xfc, 0x02] : "i32.trunc_sat_f64_s",
+        I32TruncSatF64U : [0xfc, 0x03] : "i32.trunc_sat_f64_u",
+        I64TruncSatF32S : [0xfc, 0x04] : "i64.trunc_sat_f32_s",
+        I64TruncSatF32U : [0xfc, 0x05] : "i64.trunc_sat_f32_u",
+        I64TruncSatF64S : [0xfc, 0x06] : "i64.trunc_sat_f64_s",
+        I64TruncSatF64U : [0xfc, 0x07] : "i64.trunc_sat_f64_u",
+
+        // sign extension proposal
+        I32Extend8S : [0xc0] : "i32.extend8_s",
+        I32Extend16S : [0xc1] : "i32.extend16_s",
+        I64Extend8S : [0xc2] : "i64.extend8_s",
+        I64Extend16S : [0xc3] : "i64.extend16_s",
+        I64Extend32S : [0xc4] : "i64.extend32_s",
+
+        // atomics proposal
+        MemoryAtomicNotify(MemArg<4>) : [0xfe, 0x00] : "memory.atomic.notify",
+        MemoryAtomicWait32(MemArg<4>) : [0xfe, 0x01] : "memory.atomic.wait32",
+        MemoryAtomicWait64(MemArg<8>) : [0xfe, 0x02] : "memory.atomic.wait64",
+        AtomicFence : [0xfe, 0x03, 0x00] : "atomic.fence",
+
+        I32AtomicLoad(MemArg<4>) : [0xfe, 0x10] : "i32.atomic.load",
+        I64AtomicLoad(MemArg<8>) : [0xfe, 0x11] : "i64.atomic.load",
+        I32AtomicLoad8u(MemArg<1>) : [0xfe, 0x12] : "i32.atomic.load8_u",
+        I32AtomicLoad16u(MemArg<2>) : [0xfe, 0x13] : "i32.atomic.load16_u",
+        I64AtomicLoad8u(MemArg<1>) : [0xfe, 0x14] : "i64.atomic.load8_u",
+        I64AtomicLoad16u(MemArg<2>) : [0xfe, 0x15] : "i64.atomic.load16_u",
+        I64AtomicLoad32u(MemArg<4>) : [0xfe, 0x16] : "i64.atomic.load32_u",
+        I32AtomicStore(MemArg<4>) : [0xfe, 0x17] : "i32.atomic.store",
+        I64AtomicStore(MemArg<8>) : [0xfe, 0x18] : "i64.atomic.store",
+        I32AtomicStore8(MemArg<1>) : [0xfe, 0x19] : "i32.atomic.store8",
+        I32AtomicStore16(MemArg<2>) : [0xfe, 0x1a] : "i32.atomic.store16",
+        I64AtomicStore8(MemArg<1>) : [0xfe, 0x1b] : "i64.atomic.store8",
+        I64AtomicStore16(MemArg<2>) : [0xfe, 0x1c] : "i64.atomic.store16",
+        I64AtomicStore32(MemArg<4>) : [0xfe, 0x1d] : "i64.atomic.store32",
+
+        I32AtomicRmwAdd(MemArg<4>) : [0xfe, 0x1e] : "i32.atomic.rmw.add",
+        I64AtomicRmwAdd(MemArg<8>) : [0xfe, 0x1f] : "i64.atomic.rmw.add",
+        I32AtomicRmw8AddU(MemArg<1>) : [0xfe, 0x20] : "i32.atomic.rmw8.add_u",
+        I32AtomicRmw16AddU(MemArg<2>) : [0xfe, 0x21] : "i32.atomic.rmw16.add_u",
+        I64AtomicRmw8AddU(MemArg<1>) : [0xfe, 0x22] : "i64.atomic.rmw8.add_u",
+        I64AtomicRmw16AddU(MemArg<2>) : [0xfe, 0x23] : "i64.atomic.rmw16.add_u",
+        I64AtomicRmw32AddU(MemArg<4>) : [0xfe, 0x24] : "i64.atomic.rmw32.add_u",
+
+        I32AtomicRmwSub(MemArg<4>) : [0xfe, 0x25] : "i32.atomic.rmw.sub",
+        I64AtomicRmwSub(MemArg<8>) : [0xfe, 0x26] : "i64.atomic.rmw.sub",
+        I32AtomicRmw8SubU(MemArg<1>) : [0xfe, 0x27] : "i32.atomic.rmw8.sub_u",
+        I32AtomicRmw16SubU(MemArg<2>) : [0xfe, 0x28] : "i32.atomic.rmw16.sub_u",
+        I64AtomicRmw8SubU(MemArg<1>) : [0xfe, 0x29] : "i64.atomic.rmw8.sub_u",
+        I64AtomicRmw16SubU(MemArg<2>) : [0xfe, 0x2a] : "i64.atomic.rmw16.sub_u",
+        I64AtomicRmw32SubU(MemArg<4>) : [0xfe, 0x2b] : "i64.atomic.rmw32.sub_u",
+
+        I32AtomicRmwAnd(MemArg<4>) : [0xfe, 0x2c] : "i32.atomic.rmw.and",
+        I64AtomicRmwAnd(MemArg<8>) : [0xfe, 0x2d] : "i64.atomic.rmw.and",
+        I32AtomicRmw8AndU(MemArg<1>) : [0xfe, 0x2e] : "i32.atomic.rmw8.and_u",
+        I32AtomicRmw16AndU(MemArg<2>) : [0xfe, 0x2f] : "i32.atomic.rmw16.and_u",
+        I64AtomicRmw8AndU(MemArg<1>) : [0xfe, 0x30] : "i64.atomic.rmw8.and_u",
+        I64AtomicRmw16AndU(MemArg<2>) : [0xfe, 0x31] : "i64.atomic.rmw16.and_u",
+        I64AtomicRmw32AndU(MemArg<4>) : [0xfe, 0x32] : "i64.atomic.rmw32.and_u",
+
+        I32AtomicRmwOr(MemArg<4>) : [0xfe, 0x33] : "i32.atomic.rmw.or",
+        I64AtomicRmwOr(MemArg<8>) : [0xfe, 0x34] : "i64.atomic.rmw.or",
+        I32AtomicRmw8OrU(MemArg<1>) : [0xfe, 0x35] : "i32.atomic.rmw8.or_u",
+        I32AtomicRmw16OrU(MemArg<2>) : [0xfe, 0x36] : "i32.atomic.rmw16.or_u",
+        I64AtomicRmw8OrU(MemArg<1>) : [0xfe, 0x37] : "i64.atomic.rmw8.or_u",
+        I64AtomicRmw16OrU(MemArg<2>) : [0xfe, 0x38] : "i64.atomic.rmw16.or_u",
+        I64AtomicRmw32OrU(MemArg<4>) : [0xfe, 0x39] : "i64.atomic.rmw32.or_u",
+
+        I32AtomicRmwXor(MemArg<4>) : [0xfe, 0x3a] : "i32.atomic.rmw.xor",
+        I64AtomicRmwXor(MemArg<8>) : [0xfe, 0x3b] : "i64.atomic.rmw.xor",
+        I32AtomicRmw8XorU(MemArg<1>) : [0xfe, 0x3c] : "i32.atomic.rmw8.xor_u",
+        I32AtomicRmw16XorU(MemArg<2>) : [0xfe, 0x3d] : "i32.atomic.rmw16.xor_u",
+        I64AtomicRmw8XorU(MemArg<1>) : [0xfe, 0x3e] : "i64.atomic.rmw8.xor_u",
+        I64AtomicRmw16XorU(MemArg<2>) : [0xfe, 0x3f] : "i64.atomic.rmw16.xor_u",
+        I64AtomicRmw32XorU(MemArg<4>) : [0xfe, 0x40] : "i64.atomic.rmw32.xor_u",
+
+        I32AtomicRmwXchg(MemArg<4>) : [0xfe, 0x41] : "i32.atomic.rmw.xchg",
+        I64AtomicRmwXchg(MemArg<8>) : [0xfe, 0x42] : "i64.atomic.rmw.xchg",
+        I32AtomicRmw8XchgU(MemArg<1>) : [0xfe, 0x43] : "i32.atomic.rmw8.xchg_u",
+        I32AtomicRmw16XchgU(MemArg<2>) : [0xfe, 0x44] : "i32.atomic.rmw16.xchg_u",
+        I64AtomicRmw8XchgU(MemArg<1>) : [0xfe, 0x45] : "i64.atomic.rmw8.xchg_u",
+        I64AtomicRmw16XchgU(MemArg<2>) : [0xfe, 0x46] : "i64.atomic.rmw16.xchg_u",
+        I64AtomicRmw32XchgU(MemArg<4>) : [0xfe, 0x47] : "i64.atomic.rmw32.xchg_u",
+
+        I32AtomicRmwCmpxchg(MemArg<4>) : [0xfe, 0x48] : "i32.atomic.rmw.cmpxchg",
+        I64AtomicRmwCmpxchg(MemArg<8>) : [0xfe, 0x49] : "i64.atomic.rmw.cmpxchg",
+        I32AtomicRmw8CmpxchgU(MemArg<1>) : [0xfe, 0x4a] : "i32.atomic.rmw8.cmpxchg_u",
+        I32AtomicRmw16CmpxchgU(MemArg<2>) : [0xfe, 0x4b] : "i32.atomic.rmw16.cmpxchg_u",
+        I64AtomicRmw8CmpxchgU(MemArg<1>) : [0xfe, 0x4c] : "i64.atomic.rmw8.cmpxchg_u",
+        I64AtomicRmw16CmpxchgU(MemArg<2>) : [0xfe, 0x4d] : "i64.atomic.rmw16.cmpxchg_u",
+        I64AtomicRmw32CmpxchgU(MemArg<4>) : [0xfe, 0x4e] : "i64.atomic.rmw32.cmpxchg_u",
+
+        // proposal: simd
+        //
+        // https://webassembly.github.io/simd/core/binary/instructions.html
+        V128Load(MemArg<16>) : [0xfd, 0] : "v128.load",
+        V128Load8x8S(MemArg<8>) : [0xfd, 1] : "v128.load8x8_s",
+        V128Load8x8U(MemArg<8>) : [0xfd, 2] : "v128.load8x8_u",
+        V128Load16x4S(MemArg<8>) : [0xfd, 3] : "v128.load16x4_s",
+        V128Load16x4U(MemArg<8>) : [0xfd, 4] : "v128.load16x4_u",
+        V128Load32x2S(MemArg<8>) : [0xfd, 5] : "v128.load32x2_s",
+        V128Load32x2U(MemArg<8>) : [0xfd, 6] : "v128.load32x2_u",
+        V128Load8Splat(MemArg<1>) : [0xfd, 7] : "v128.load8_splat",
+        V128Load16Splat(MemArg<2>) : [0xfd, 8] : "v128.load16_splat",
+        V128Load32Splat(MemArg<4>) : [0xfd, 9] : "v128.load32_splat",
+        V128Load64Splat(MemArg<8>) : [0xfd, 10] : "v128.load64_splat",
+        V128Load32Zero(MemArg<4>) : [0xfd, 92] : "v128.load32_zero",
+        V128Load64Zero(MemArg<8>) : [0xfd, 93] : "v128.load64_zero",
+        V128Store(MemArg<16>) : [0xfd, 11] : "v128.store",
+
+        V128Load8Lane(LoadOrStoreLane<1>) : [0xfd, 84] : "v128.load8_lane",
+        V128Load16Lane(LoadOrStoreLane<2>) : [0xfd, 85] : "v128.load16_lane",
+        V128Load32Lane(LoadOrStoreLane<4>) : [0xfd, 86] : "v128.load32_lane",
+        V128Load64Lane(LoadOrStoreLane<8>): [0xfd, 87] : "v128.load64_lane",
+        V128Store8Lane(LoadOrStoreLane<1>) : [0xfd, 88] : "v128.store8_lane",
+        V128Store16Lane(LoadOrStoreLane<2>) : [0xfd, 89] : "v128.store16_lane",
+        V128Store32Lane(LoadOrStoreLane<4>) : [0xfd, 90] : "v128.store32_lane",
+        V128Store64Lane(LoadOrStoreLane<8>) : [0xfd, 91] : "v128.store64_lane",
+
+        V128Const(V128Const) : [0xfd, 12] : "v128.const",
+        I8x16Shuffle(I8x16Shuffle) : [0xfd, 13] : "i8x16.shuffle",
+
+        I8x16ExtractLaneS(LaneArg) : [0xfd, 21] : "i8x16.extract_lane_s",
+        I8x16ExtractLaneU(LaneArg) : [0xfd, 22] : "i8x16.extract_lane_u",
+        I8x16ReplaceLane(LaneArg) : [0xfd, 23] : "i8x16.replace_lane",
+        I16x8ExtractLaneS(LaneArg) : [0xfd, 24] : "i16x8.extract_lane_s",
+        I16x8ExtractLaneU(LaneArg) : [0xfd, 25] : "i16x8.extract_lane_u",
+        I16x8ReplaceLane(LaneArg) : [0xfd, 26] : "i16x8.replace_lane",
+        I32x4ExtractLane(LaneArg) : [0xfd, 27] : "i32x4.extract_lane",
+        I32x4ReplaceLane(LaneArg) : [0xfd, 28] : "i32x4.replace_lane",
+        I64x2ExtractLane(LaneArg) : [0xfd, 29] : "i64x2.extract_lane",
+        I64x2ReplaceLane(LaneArg) : [0xfd, 30] : "i64x2.replace_lane",
+        F32x4ExtractLane(LaneArg) : [0xfd, 31] : "f32x4.extract_lane",
+        F32x4ReplaceLane(LaneArg) : [0xfd, 32] : "f32x4.replace_lane",
+        F64x2ExtractLane(LaneArg) : [0xfd, 33] : "f64x2.extract_lane",
+        F64x2ReplaceLane(LaneArg) : [0xfd, 34] : "f64x2.replace_lane",
+
+        I8x16Swizzle : [0xfd, 14] : "i8x16.swizzle",
+        I8x16Splat : [0xfd, 15] : "i8x16.splat",
+        I16x8Splat : [0xfd, 16] : "i16x8.splat",
+        I32x4Splat : [0xfd, 17] : "i32x4.splat",
+        I64x2Splat : [0xfd, 18] : "i64x2.splat",
+        F32x4Splat : [0xfd, 19] : "f32x4.splat",
+        F64x2Splat : [0xfd, 20] : "f64x2.splat",
+
+        I8x16Eq : [0xfd, 35] : "i8x16.eq",
+        I8x16Ne : [0xfd, 36] : "i8x16.ne",
+        I8x16LtS : [0xfd, 37] : "i8x16.lt_s",
+        I8x16LtU : [0xfd, 38] : "i8x16.lt_u",
+        I8x16GtS : [0xfd, 39] : "i8x16.gt_s",
+        I8x16GtU : [0xfd, 40] : "i8x16.gt_u",
+        I8x16LeS : [0xfd, 41] : "i8x16.le_s",
+        I8x16LeU : [0xfd, 42] : "i8x16.le_u",
+        I8x16GeS : [0xfd, 43] : "i8x16.ge_s",
+        I8x16GeU : [0xfd, 44] : "i8x16.ge_u",
+
+        I16x8Eq : [0xfd, 45] : "i16x8.eq",
+        I16x8Ne : [0xfd, 46] : "i16x8.ne",
+        I16x8LtS : [0xfd, 47] : "i16x8.lt_s",
+        I16x8LtU : [0xfd, 48] : "i16x8.lt_u",
+        I16x8GtS : [0xfd, 49] : "i16x8.gt_s",
+        I16x8GtU : [0xfd, 50] : "i16x8.gt_u",
+        I16x8LeS : [0xfd, 51] : "i16x8.le_s",
+        I16x8LeU : [0xfd, 52] : "i16x8.le_u",
+        I16x8GeS : [0xfd, 53] : "i16x8.ge_s",
+        I16x8GeU : [0xfd, 54] : "i16x8.ge_u",
+
+        I32x4Eq : [0xfd, 55] : "i32x4.eq",
+        I32x4Ne : [0xfd, 56] : "i32x4.ne",
+        I32x4LtS : [0xfd, 57] : "i32x4.lt_s",
+        I32x4LtU : [0xfd, 58] : "i32x4.lt_u",
+        I32x4GtS : [0xfd, 59] : "i32x4.gt_s",
+        I32x4GtU : [0xfd, 60] : "i32x4.gt_u",
+        I32x4LeS : [0xfd, 61] : "i32x4.le_s",
+        I32x4LeU : [0xfd, 62] : "i32x4.le_u",
+        I32x4GeS : [0xfd, 63] : "i32x4.ge_s",
+        I32x4GeU : [0xfd, 64] : "i32x4.ge_u",
+
+        I64x2Eq : [0xfd, 214] : "i64x2.eq",
+        I64x2Ne : [0xfd, 215] : "i64x2.ne",
+        I64x2LtS : [0xfd, 216] : "i64x2.lt_s",
+        I64x2GtS : [0xfd, 217] : "i64x2.gt_s",
+        I64x2LeS : [0xfd, 218] : "i64x2.le_s",
+        I64x2GeS : [0xfd, 219] : "i64x2.ge_s",
+
+        F32x4Eq : [0xfd, 65] : "f32x4.eq",
+        F32x4Ne : [0xfd, 66] : "f32x4.ne",
+        F32x4Lt : [0xfd, 67] : "f32x4.lt",
+        F32x4Gt : [0xfd, 68] : "f32x4.gt",
+        F32x4Le : [0xfd, 69] : "f32x4.le",
+        F32x4Ge : [0xfd, 70] : "f32x4.ge",
+
+        F64x2Eq : [0xfd, 71] : "f64x2.eq",
+        F64x2Ne : [0xfd, 72] : "f64x2.ne",
+        F64x2Lt : [0xfd, 73] : "f64x2.lt",
+        F64x2Gt : [0xfd, 74] : "f64x2.gt",
+        F64x2Le : [0xfd, 75] : "f64x2.le",
+        F64x2Ge : [0xfd, 76] : "f64x2.ge",
+
+        V128Not : [0xfd, 77] : "v128.not",
+        V128And : [0xfd, 78] : "v128.and",
+        V128Andnot : [0xfd, 79] : "v128.andnot",
+        V128Or : [0xfd, 80] : "v128.or",
+        V128Xor : [0xfd, 81] : "v128.xor",
+        V128Bitselect : [0xfd, 82] : "v128.bitselect",
+        V128AnyTrue : [0xfd, 83] : "v128.any_true",
+
+        I8x16Abs : [0xfd, 96] : "i8x16.abs",
+        I8x16Neg : [0xfd, 97] : "i8x16.neg",
+        I8x16Popcnt : [0xfd, 98] : "i8x16.popcnt",
+        I8x16AllTrue : [0xfd, 99] : "i8x16.all_true",
+        I8x16Bitmask : [0xfd, 100] : "i8x16.bitmask",
+        I8x16NarrowI16x8S : [0xfd, 101] : "i8x16.narrow_i16x8_s",
+        I8x16NarrowI16x8U : [0xfd, 102] : "i8x16.narrow_i16x8_u",
+        I8x16Shl : [0xfd, 107] : "i8x16.shl",
+        I8x16ShrS : [0xfd, 108] : "i8x16.shr_s",
+        I8x16ShrU : [0xfd, 109] : "i8x16.shr_u",
+        I8x16Add : [0xfd, 110] : "i8x16.add",
+        I8x16AddSatS : [0xfd, 111] : "i8x16.add_sat_s",
+        I8x16AddSatU : [0xfd, 112] : "i8x16.add_sat_u",
+        I8x16Sub : [0xfd, 113] : "i8x16.sub",
+        I8x16SubSatS : [0xfd, 114] : "i8x16.sub_sat_s",
+        I8x16SubSatU : [0xfd, 115] : "i8x16.sub_sat_u",
+        I8x16MinS : [0xfd, 118] : "i8x16.min_s",
+        I8x16MinU : [0xfd, 119] : "i8x16.min_u",
+        I8x16MaxS : [0xfd, 120] : "i8x16.max_s",
+        I8x16MaxU : [0xfd, 121] : "i8x16.max_u",
+        I8x16AvgrU : [0xfd, 123] : "i8x16.avgr_u",
+
+        I16x8ExtAddPairwiseI8x16S : [0xfd, 124] : "i16x8.extadd_pairwise_i8x16_s",
+        I16x8ExtAddPairwiseI8x16U : [0xfd, 125] : "i16x8.extadd_pairwise_i8x16_u",
+        I16x8Abs : [0xfd, 128] : "i16x8.abs",
+        I16x8Neg : [0xfd, 129] : "i16x8.neg",
+        I16x8Q15MulrSatS : [0xfd, 130] : "i16x8.q15mulr_sat_s",
+        I16x8AllTrue : [0xfd, 131] : "i16x8.all_true",
+        I16x8Bitmask : [0xfd, 132] : "i16x8.bitmask",
+        I16x8NarrowI32x4S : [0xfd, 133] : "i16x8.narrow_i32x4_s",
+        I16x8NarrowI32x4U : [0xfd, 134] : "i16x8.narrow_i32x4_u",
+        I16x8ExtendLowI8x16S : [0xfd, 135] : "i16x8.extend_low_i8x16_s",
+        I16x8ExtendHighI8x16S : [0xfd, 136] : "i16x8.extend_high_i8x16_s",
+        I16x8ExtendLowI8x16U : [0xfd, 137] : "i16x8.extend_low_i8x16_u",
+        I16x8ExtendHighI8x16u : [0xfd, 138] : "i16x8.extend_high_i8x16_u",
+        I16x8Shl : [0xfd, 139] : "i16x8.shl",
+        I16x8ShrS : [0xfd, 140] : "i16x8.shr_s",
+        I16x8ShrU : [0xfd, 141] : "i16x8.shr_u",
+        I16x8Add : [0xfd, 142] : "i16x8.add",
+        I16x8AddSatS : [0xfd, 143] : "i16x8.add_sat_s",
+        I16x8AddSatU : [0xfd, 144] : "i16x8.add_sat_u",
+        I16x8Sub : [0xfd, 145] : "i16x8.sub",
+        I16x8SubSatS : [0xfd, 146] : "i16x8.sub_sat_s",
+        I16x8SubSatU : [0xfd, 147] : "i16x8.sub_sat_u",
+        I16x8Mul : [0xfd, 149] : "i16x8.mul",
+        I16x8MinS : [0xfd, 150] : "i16x8.min_s",
+        I16x8MinU : [0xfd, 151] : "i16x8.min_u",
+        I16x8MaxS : [0xfd, 152] : "i16x8.max_s",
+        I16x8MaxU : [0xfd, 153] : "i16x8.max_u",
+        I16x8AvgrU : [0xfd, 155] : "i16x8.avgr_u",
+        I16x8ExtMulLowI8x16S : [0xfd, 156] : "i16x8.extmul_low_i8x16_s",
+        I16x8ExtMulHighI8x16S : [0xfd, 157] : "i16x8.extmul_high_i8x16_s",
+        I16x8ExtMulLowI8x16U : [0xfd, 158] : "i16x8.extmul_low_i8x16_u",
+        I16x8ExtMulHighI8x16U : [0xfd, 159] : "i16x8.extmul_high_i8x16_u",
+
+        I32x4ExtAddPairwiseI16x8S : [0xfd, 126] : "i32x4.extadd_pairwise_i16x8_s",
+        I32x4ExtAddPairwiseI16x8U : [0xfd, 127] : "i32x4.extadd_pairwise_i16x8_u",
+        I32x4Abs : [0xfd, 160] : "i32x4.abs",
+        I32x4Neg : [0xfd, 161] : "i32x4.neg",
+        I32x4AllTrue : [0xfd, 163] : "i32x4.all_true",
+        I32x4Bitmask : [0xfd, 164] : "i32x4.bitmask",
+        I32x4ExtendLowI16x8S : [0xfd, 167] : "i32x4.extend_low_i16x8_s",
+        I32x4ExtendHighI16x8S : [0xfd, 168] : "i32x4.extend_high_i16x8_s",
+        I32x4ExtendLowI16x8U : [0xfd, 169] : "i32x4.extend_low_i16x8_u",
+        I32x4ExtendHighI16x8U : [0xfd, 170] : "i32x4.extend_high_i16x8_u",
+        I32x4Shl : [0xfd, 171] : "i32x4.shl",
+        I32x4ShrS : [0xfd, 172] : "i32x4.shr_s",
+        I32x4ShrU : [0xfd, 173] : "i32x4.shr_u",
+        I32x4Add : [0xfd, 174] : "i32x4.add",
+        I32x4Sub : [0xfd, 177] : "i32x4.sub",
+        I32x4Mul : [0xfd, 181] : "i32x4.mul",
+        I32x4MinS : [0xfd, 182] : "i32x4.min_s",
+        I32x4MinU : [0xfd, 183] : "i32x4.min_u",
+        I32x4MaxS : [0xfd, 184] : "i32x4.max_s",
+        I32x4MaxU : [0xfd, 185] : "i32x4.max_u",
+        I32x4DotI16x8S : [0xfd, 186] : "i32x4.dot_i16x8_s",
+        I32x4ExtMulLowI16x8S : [0xfd, 188] : "i32x4.extmul_low_i16x8_s",
+        I32x4ExtMulHighI16x8S : [0xfd, 189] : "i32x4.extmul_high_i16x8_s",
+        I32x4ExtMulLowI16x8U : [0xfd, 190] : "i32x4.extmul_low_i16x8_u",
+        I32x4ExtMulHighI16x8U : [0xfd, 191] : "i32x4.extmul_high_i16x8_u",
+
+        I64x2Abs : [0xfd, 192] : "i64x2.abs",
+        I64x2Neg : [0xfd, 193] : "i64x2.neg",
+        I64x2AllTrue : [0xfd, 195] : "i64x2.all_true",
+        I64x2Bitmask : [0xfd, 196] : "i64x2.bitmask",
+        I64x2ExtendLowI32x4S : [0xfd, 199] : "i64x2.extend_low_i32x4_s",
+        I64x2ExtendHighI32x4S : [0xfd, 200] : "i64x2.extend_high_i32x4_s",
+        I64x2ExtendLowI32x4U : [0xfd, 201] : "i64x2.extend_low_i32x4_u",
+        I64x2ExtendHighI32x4U : [0xfd, 202] : "i64x2.extend_high_i32x4_u",
+        I64x2Shl : [0xfd, 203] : "i64x2.shl",
+        I64x2ShrS : [0xfd, 204] : "i64x2.shr_s",
+        I64x2ShrU : [0xfd, 205] : "i64x2.shr_u",
+        I64x2Add : [0xfd, 206] : "i64x2.add",
+        I64x2Sub : [0xfd, 209] : "i64x2.sub",
+        I64x2Mul : [0xfd, 213] : "i64x2.mul",
+        I64x2ExtMulLowI32x4S : [0xfd, 220] : "i64x2.extmul_low_i32x4_s",
+        I64x2ExtMulHighI32x4S : [0xfd, 221] : "i64x2.extmul_high_i32x4_s",
+        I64x2ExtMulLowI32x4U : [0xfd, 222] : "i64x2.extmul_low_i32x4_u",
+        I64x2ExtMulHighI32x4U : [0xfd, 223] : "i64x2.extmul_high_i32x4_u",
+
+        F32x4Ceil : [0xfd, 103] : "f32x4.ceil",
+        F32x4Floor : [0xfd, 104] : "f32x4.floor",
+        F32x4Trunc : [0xfd, 105] : "f32x4.trunc",
+        F32x4Nearest : [0xfd, 106] : "f32x4.nearest",
+        F32x4Abs : [0xfd, 224] : "f32x4.abs",
+        F32x4Neg : [0xfd, 225] : "f32x4.neg",
+        F32x4Sqrt : [0xfd, 227] : "f32x4.sqrt",
+        F32x4Add : [0xfd, 228] : "f32x4.add",
+        F32x4Sub : [0xfd, 229] : "f32x4.sub",
+        F32x4Mul : [0xfd, 230] : "f32x4.mul",
+        F32x4Div : [0xfd, 231] : "f32x4.div",
+        F32x4Min : [0xfd, 232] : "f32x4.min",
+        F32x4Max : [0xfd, 233] : "f32x4.max",
+        F32x4PMin : [0xfd, 234] : "f32x4.pmin",
+        F32x4PMax : [0xfd, 235] : "f32x4.pmax",
+
+        F64x2Ceil : [0xfd, 116] : "f64x2.ceil",
+        F64x2Floor : [0xfd, 117] : "f64x2.floor",
+        F64x2Trunc : [0xfd, 122] : "f64x2.trunc",
+        F64x2Nearest : [0xfd, 148] : "f64x2.nearest",
+        F64x2Abs : [0xfd, 236] : "f64x2.abs",
+        F64x2Neg : [0xfd, 237] : "f64x2.neg",
+        F64x2Sqrt : [0xfd, 239] : "f64x2.sqrt",
+        F64x2Add : [0xfd, 240] : "f64x2.add",
+        F64x2Sub : [0xfd, 241] : "f64x2.sub",
+        F64x2Mul : [0xfd, 242] : "f64x2.mul",
+        F64x2Div : [0xfd, 243] : "f64x2.div",
+        F64x2Min : [0xfd, 244] : "f64x2.min",
+        F64x2Max : [0xfd, 245] : "f64x2.max",
+        F64x2PMin : [0xfd, 246] : "f64x2.pmin",
+        F64x2PMax : [0xfd, 247] : "f64x2.pmax",
+
+        I32x4TruncSatF32x4S : [0xfd, 248] : "i32x4.trunc_sat_f32x4_s",
+        I32x4TruncSatF32x4U : [0xfd, 249] : "i32x4.trunc_sat_f32x4_u",
+        F32x4ConvertI32x4S : [0xfd, 250] : "f32x4.convert_i32x4_s",
+        F32x4ConvertI32x4U : [0xfd, 251] : "f32x4.convert_i32x4_u",
+        I32x4TruncSatF64x2SZero : [0xfd, 252] : "i32x4.trunc_sat_f64x2_s_zero",
+        I32x4TruncSatF64x2UZero : [0xfd, 253] : "i32x4.trunc_sat_f64x2_u_zero",
+        F64x2ConvertLowI32x4S : [0xfd, 254] : "f64x2.convert_low_i32x4_s",
+        F64x2ConvertLowI32x4U : [0xfd, 255] : "f64x2.convert_low_i32x4_u",
+        F32x4DemoteF64x2Zero : [0xfd, 94] : "f32x4.demote_f64x2_zero",
+        F64x2PromoteLowF32x4 : [0xfd, 95] : "f64x2.promote_low_f32x4",
+
+        // Exception handling proposal
+        ThrowRef : [0x0a] : "throw_ref",
+        TryTable(TryTable<'a>) : [0x1f] : "try_table",
+        Throw(Index<'a>) : [0x08] : "throw",
+
+        // Deprecated exception handling optocdes
+        Try(Box<BlockType<'a>>) : [0x06] : "try",
+        Catch(Index<'a>) : [0x07] : "catch",
+        Rethrow(Index<'a>) : [0x09] : "rethrow",
+        Delegate(Index<'a>) : [0x18] : "delegate",
+        CatchAll : [0x19] : "catch_all",
+
+        // Relaxed SIMD proposal
+        I8x16RelaxedSwizzle : [0xfd, 0x100]: "i8x16.relaxed_swizzle",
+        I32x4RelaxedTruncF32x4S : [0xfd, 0x101]: "i32x4.relaxed_trunc_f32x4_s",
+        I32x4RelaxedTruncF32x4U : [0xfd, 0x102]: "i32x4.relaxed_trunc_f32x4_u",
+        I32x4RelaxedTruncF64x2SZero : [0xfd, 0x103]: "i32x4.relaxed_trunc_f64x2_s_zero",
+        I32x4RelaxedTruncF64x2UZero : [0xfd, 0x104]: "i32x4.relaxed_trunc_f64x2_u_zero",
+        F32x4RelaxedMadd : [0xfd, 0x105]: "f32x4.relaxed_madd",
+        F32x4RelaxedNmadd : [0xfd, 0x106]: "f32x4.relaxed_nmadd",
+        F64x2RelaxedMadd : [0xfd, 0x107]: "f64x2.relaxed_madd",
+        F64x2RelaxedNmadd : [0xfd, 0x108]: "f64x2.relaxed_nmadd",
+        I8x16RelaxedLaneselect : [0xfd, 0x109]: "i8x16.relaxed_laneselect",
+        I16x8RelaxedLaneselect : [0xfd, 0x10A]: "i16x8.relaxed_laneselect",
+        I32x4RelaxedLaneselect : [0xfd, 0x10B]: "i32x4.relaxed_laneselect",
+        I64x2RelaxedLaneselect : [0xfd, 0x10C]: "i64x2.relaxed_laneselect",
+        F32x4RelaxedMin : [0xfd, 0x10D]: "f32x4.relaxed_min",
+        F32x4RelaxedMax : [0xfd, 0x10E]: "f32x4.relaxed_max",
+        F64x2RelaxedMin : [0xfd, 0x10F]: "f64x2.relaxed_min",
+        F64x2RelaxedMax : [0xfd, 0x110]: "f64x2.relaxed_max",
+        I16x8RelaxedQ15mulrS: [0xfd, 0x111]: "i16x8.relaxed_q15mulr_s",
+        I16x8RelaxedDotI8x16I7x16S: [0xfd, 0x112]: "i16x8.relaxed_dot_i8x16_i7x16_s",
+        I32x4RelaxedDotI8x16I7x16AddS: [0xfd, 0x113]: "i32x4.relaxed_dot_i8x16_i7x16_add_s",
+    }
+}
+
+// As shown in #1095 the size of this variant is somewhat performance-sensitive
+// since big `*.wat` files will have a lot of these. This is a small ratchet to
+// make sure that this enum doesn't become larger than it already is, although
+// ideally it also wouldn't be as large as it is now.
+const _: () = {
+    let size = std::mem::size_of::<Instruction<'_>>();
+    let pointer = std::mem::size_of::<u64>();
+    assert!(size <= pointer * 10);
+};
+
+impl<'a> Instruction<'a> {
+    pub(crate) fn needs_data_count(&self) -> bool {
+        match self {
+            Instruction::MemoryInit(_)
+            | Instruction::DataDrop(_)
+            | Instruction::ArrayNewData(_)
+            | Instruction::ArrayInitData(_) => true,
+            _ => false,
+        }
+    }
+}
+
+/// Extra information associated with block-related instructions.
+///
+/// This is used to label blocks and also annotate what types are expected for
+/// the block.
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub struct BlockType<'a> {
+    pub label: Option<Id<'a>>,
+    pub label_name: Option<NameAnnotation<'a>>,
+    pub ty: TypeUse<'a, FunctionType<'a>>,
+}
+
+impl<'a> Parse<'a> for BlockType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(BlockType {
+            label: parser.parse()?,
+            label_name: parser.parse()?,
+            ty: parser
+                .parse::<TypeUse<'a, FunctionTypeNoNames<'a>>>()?
+                .into(),
+        })
+    }
+}
+
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub struct TryTable<'a> {
+    pub block: Box<BlockType<'a>>,
+    pub catches: Vec<TryTableCatch<'a>>,
+}
+
+impl<'a> Parse<'a> for TryTable<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let block = parser.parse()?;
+
+        let mut catches = Vec::new();
+        while parser.peek::<LParen>()?
+            && (parser.peek2::<kw::catch>()?
+                || parser.peek2::<kw::catch_ref>()?
+                || parser.peek2::<kw::catch_all>()?
+                || parser.peek2::<kw::catch_all_ref>()?)
+        {
+            catches.push(parser.parens(|p| {
+                let kind = if parser.peek::<kw::catch_ref>()? {
+                    p.parse::<kw::catch_ref>()?;
+                    TryTableCatchKind::CatchRef(p.parse()?)
+                } else if parser.peek::<kw::catch>()? {
+                    p.parse::<kw::catch>()?;
+                    TryTableCatchKind::Catch(p.parse()?)
+                } else if parser.peek::<kw::catch_all>()? {
+                    p.parse::<kw::catch_all>()?;
+                    TryTableCatchKind::CatchAll
+                } else {
+                    p.parse::<kw::catch_all_ref>()?;
+                    TryTableCatchKind::CatchAllRef
+                };
+
+                Ok(TryTableCatch {
+                    kind,
+                    label: p.parse()?,
+                })
+            })?);
+        }
+
+        Ok(TryTable { block, catches })
+    }
+}
+
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub enum TryTableCatchKind<'a> {
+    // Catch a tagged exception, do not capture an exnref.
+    Catch(Index<'a>),
+    // Catch a tagged exception, and capture the exnref.
+    CatchRef(Index<'a>),
+    // Catch any exception, do not capture an exnref.
+    CatchAll,
+    // Catch any exception, and capture the exnref.
+    CatchAllRef,
+}
+
+impl<'a> TryTableCatchKind<'a> {
+    #[allow(missing_docs)]
+    pub fn tag_index_mut(&mut self) -> Option<&mut Index<'a>> {
+        match self {
+            TryTableCatchKind::Catch(tag) | TryTableCatchKind::CatchRef(tag) => Some(tag),
+            TryTableCatchKind::CatchAll | TryTableCatchKind::CatchAllRef => None,
+        }
+    }
+}
+
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub struct TryTableCatch<'a> {
+    pub kind: TryTableCatchKind<'a>,
+    pub label: Index<'a>,
+}
+
+/// Extra information associated with the func.bind instruction.
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub struct FuncBindType<'a> {
+    pub ty: TypeUse<'a, FunctionType<'a>>,
+}
+
+impl<'a> Parse<'a> for FuncBindType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(FuncBindType {
+            ty: parser
+                .parse::<TypeUse<'a, FunctionTypeNoNames<'a>>>()?
+                .into(),
+        })
+    }
+}
+
+/// Extra information associated with the let instruction.
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub struct LetType<'a> {
+    pub block: Box<BlockType<'a>>,
+    pub locals: Box<[Local<'a>]>,
+}
+
+impl<'a> Parse<'a> for LetType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(LetType {
+            block: parser.parse()?,
+            locals: Local::parse_remainder(parser)?.into(),
+        })
+    }
+}
+
+/// Extra information associated with the `br_table` instruction.
+#[allow(missing_docs)]
+#[derive(Debug)]
+pub struct BrTableIndices<'a> {
+    pub labels: Vec<Index<'a>>,
+    pub default: Index<'a>,
+}
+
+impl<'a> Parse<'a> for BrTableIndices<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut labels = vec![parser.parse()?];
+        while parser.peek::<Index>()? {
+            labels.push(parser.parse()?);
+        }
+        let default = labels.pop().unwrap();
+        Ok(BrTableIndices { labels, default })
+    }
+}
+
+/// Payload for lane-related instructions. Unsigned with no + prefix.
+#[derive(Debug)]
+pub struct LaneArg {
+    /// The lane argument.
+    pub lane: u8,
+}
+
+impl<'a> Parse<'a> for LaneArg {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let lane = parser.step(|c| {
+            if let Some((i, rest)) = c.integer()? {
+                if i.sign() == None {
+                    let (src, radix) = i.val();
+                    let val = u8::from_str_radix(src, radix)
+                        .map_err(|_| c.error("malformed lane index"))?;
+                    Ok((val, rest))
+                } else {
+                    Err(c.error("unexpected token"))
+                }
+            } else {
+                Err(c.error("expected a lane index"))
+            }
+        })?;
+        Ok(LaneArg { lane })
+    }
+}
+
+/// Payload for memory-related instructions indicating offset/alignment of
+/// memory accesses.
+#[derive(Debug)]
+pub struct MemArg<'a> {
+    /// The alignment of this access.
+    ///
+    /// This is not stored as a log, this is the actual alignment (e.g. 1, 2, 4,
+    /// 8, etc).
+    pub align: u32,
+    /// The offset, in bytes of this access.
+    pub offset: u64,
+    /// The memory index we're accessing
+    pub memory: Index<'a>,
+}
+
+impl<'a> MemArg<'a> {
+    fn parse(parser: Parser<'a>, default_align: u32) -> Result<Self> {
+        fn parse_field<T>(
+            name: &str,
+            parser: Parser<'_>,
+            f: impl FnOnce(Cursor<'_>, &str, u32) -> Result<T>,
+        ) -> Result<Option<T>> {
+            parser.step(|c| {
+                let (kw, rest) = match c.keyword()? {
+                    Some(p) => p,
+                    None => return Ok((None, c)),
+                };
+                if !kw.starts_with(name) {
+                    return Ok((None, c));
+                }
+                let kw = &kw[name.len()..];
+                if !kw.starts_with('=') {
+                    return Ok((None, c));
+                }
+                let num = &kw[1..];
+                let num = if let Some(stripped) = num.strip_prefix("0x") {
+                    f(c, stripped, 16)?
+                } else {
+                    f(c, num, 10)?
+                };
+
+                Ok((Some(num), rest))
+            })
+        }
+
+        fn parse_u32(name: &str, parser: Parser<'_>) -> Result<Option<u32>> {
+            parse_field(name, parser, |c, num, radix| {
+                u32::from_str_radix(num, radix).map_err(|_| c.error("i32 constant out of range"))
+            })
+        }
+
+        fn parse_u64(name: &str, parser: Parser<'_>) -> Result<Option<u64>> {
+            parse_field(name, parser, |c, num, radix| {
+                u64::from_str_radix(num, radix).map_err(|_| c.error("i64 constant out of range"))
+            })
+        }
+
+        let memory = parser
+            .parse::<Option<_>>()?
+            .unwrap_or_else(|| Index::Num(0, parser.prev_span()));
+        let offset = parse_u64("offset", parser)?.unwrap_or(0);
+        let align = match parse_u32("align", parser)? {
+            Some(n) if !n.is_power_of_two() => {
+                return Err(parser.error("alignment must be a power of two"))
+            }
+            n => n.unwrap_or(default_align),
+        };
+
+        Ok(MemArg {
+            offset,
+            align,
+            memory,
+        })
+    }
+}
+
+/// Extra data associated with the `loadN_lane` and `storeN_lane` instructions.
+#[derive(Debug)]
+pub struct LoadOrStoreLane<'a> {
+    /// The memory argument for this instruction.
+    pub memarg: MemArg<'a>,
+    /// The lane argument for this instruction.
+    pub lane: LaneArg,
+}
+
+impl<'a> LoadOrStoreLane<'a> {
+    fn parse(parser: Parser<'a>, default_align: u32) -> Result<Self> {
+        // This is sort of funky. The first integer we see could be the lane
+        // index, but it could also be the memory index. To determine what it is
+        // then if we see a second integer we need to look further.
+        let has_memarg = parser.step(|c| match c.integer()? {
+            Some((_, after_int)) => {
+                // Two integers in a row? That means that the first one is the
+                // memory index and the second must be the lane index.
+                if after_int.integer()?.is_some() {
+                    return Ok((true, c));
+                }
+
+                // If the first integer is trailed by `offset=...` or
+                // `align=...` then this is definitely a memarg.
+                if let Some((kw, _)) = after_int.keyword()? {
+                    if kw.starts_with("offset=") || kw.starts_with("align=") {
+                        return Ok((true, c));
+                    }
+                }
+
+                // Otherwise the first integer was trailed by something that
+                // didn't look like a memarg, so this must be the lane index.
+                Ok((false, c))
+            }
+
+            // Not an integer here? That must mean that this must be the memarg
+            // first followed by the trailing index.
+            None => Ok((true, c)),
+        })?;
+        Ok(LoadOrStoreLane {
+            memarg: if has_memarg {
+                MemArg::parse(parser, default_align)?
+            } else {
+                MemArg {
+                    align: default_align,
+                    offset: 0,
+                    memory: Index::Num(0, parser.prev_span()),
+                }
+            },
+            lane: LaneArg::parse(parser)?,
+        })
+    }
+}
+
+/// Extra data associated with the `call_indirect` instruction.
+#[derive(Debug)]
+pub struct CallIndirect<'a> {
+    /// The table that this call is going to be indexing.
+    pub table: Index<'a>,
+    /// Type type signature that this `call_indirect` instruction is using.
+    pub ty: TypeUse<'a, FunctionType<'a>>,
+}
+
+impl<'a> Parse<'a> for CallIndirect<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let prev_span = parser.prev_span();
+        let table: Option<_> = parser.parse()?;
+        let ty = parser.parse::<TypeUse<'a, FunctionTypeNoNames<'a>>>()?;
+        Ok(CallIndirect {
+            table: table.unwrap_or(Index::Num(0, prev_span)),
+            ty: ty.into(),
+        })
+    }
+}
+
+/// Extra data associated with the `table.init` instruction
+#[derive(Debug)]
+pub struct TableInit<'a> {
+    /// The index of the table we're copying into.
+    pub table: Index<'a>,
+    /// The index of the element segment we're copying into a table.
+    pub elem: Index<'a>,
+}
+
+impl<'a> Parse<'a> for TableInit<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let prev_span = parser.prev_span();
+        let (elem, table) = if parser.peek2::<Index>()? {
+            let table = parser.parse()?;
+            (parser.parse()?, table)
+        } else {
+            (parser.parse()?, Index::Num(0, prev_span))
+        };
+        Ok(TableInit { table, elem })
+    }
+}
+
+/// Extra data associated with the `table.copy` instruction.
+#[derive(Debug)]
+pub struct TableCopy<'a> {
+    /// The index of the destination table to copy into.
+    pub dst: Index<'a>,
+    /// The index of the source table to copy from.
+    pub src: Index<'a>,
+}
+
+impl<'a> Parse<'a> for TableCopy<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let (dst, src) = match parser.parse::<Option<_>>()? {
+            Some(dst) => (dst, parser.parse()?),
+            None => (
+                Index::Num(0, parser.prev_span()),
+                Index::Num(0, parser.prev_span()),
+            ),
+        };
+        Ok(TableCopy { dst, src })
+    }
+}
+
+/// Extra data associated with unary table instructions.
+#[derive(Debug)]
+pub struct TableArg<'a> {
+    /// The index of the table argument.
+    pub dst: Index<'a>,
+}
+
+impl<'a> Parse<'a> for TableArg<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let dst = if let Some(dst) = parser.parse()? {
+            dst
+        } else {
+            Index::Num(0, parser.prev_span())
+        };
+        Ok(TableArg { dst })
+    }
+}
+
+/// Extra data associated with unary memory instructions.
+#[derive(Debug)]
+pub struct MemoryArg<'a> {
+    /// The index of the memory space.
+    pub mem: Index<'a>,
+}
+
+impl<'a> Parse<'a> for MemoryArg<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mem = if let Some(mem) = parser.parse()? {
+            mem
+        } else {
+            Index::Num(0, parser.prev_span())
+        };
+        Ok(MemoryArg { mem })
+    }
+}
+
+/// Extra data associated with the `memory.init` instruction
+#[derive(Debug)]
+pub struct MemoryInit<'a> {
+    /// The index of the data segment we're copying into memory.
+    pub data: Index<'a>,
+    /// The index of the memory we're copying into,
+    pub mem: Index<'a>,
+}
+
+impl<'a> Parse<'a> for MemoryInit<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let prev_span = parser.prev_span();
+        let (data, mem) = if parser.peek2::<Index>()? {
+            let memory = parser.parse()?;
+            (parser.parse()?, memory)
+        } else {
+            (parser.parse()?, Index::Num(0, prev_span))
+        };
+        Ok(MemoryInit { data, mem })
+    }
+}
+
+/// Extra data associated with the `memory.copy` instruction
+#[derive(Debug)]
+pub struct MemoryCopy<'a> {
+    /// The index of the memory we're copying from.
+    pub src: Index<'a>,
+    /// The index of the memory we're copying to.
+    pub dst: Index<'a>,
+}
+
+impl<'a> Parse<'a> for MemoryCopy<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let (src, dst) = match parser.parse()? {
+            Some(dst) => (parser.parse()?, dst),
+            None => (
+                Index::Num(0, parser.prev_span()),
+                Index::Num(0, parser.prev_span()),
+            ),
+        };
+        Ok(MemoryCopy { src, dst })
+    }
+}
+
+/// Extra data associated with the `struct.get/set` instructions
+#[derive(Debug)]
+pub struct StructAccess<'a> {
+    /// The index of the struct type we're accessing.
+    pub r#struct: Index<'a>,
+    /// The index of the field of the struct we're accessing
+    pub field: Index<'a>,
+}
+
+impl<'a> Parse<'a> for StructAccess<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(StructAccess {
+            r#struct: parser.parse()?,
+            field: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `array.fill` instruction
+#[derive(Debug)]
+pub struct ArrayFill<'a> {
+    /// The index of the array type we're filling.
+    pub array: Index<'a>,
+}
+
+impl<'a> Parse<'a> for ArrayFill<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(ArrayFill {
+            array: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `array.copy` instruction
+#[derive(Debug)]
+pub struct ArrayCopy<'a> {
+    /// The index of the array type we're copying to.
+    pub dest_array: Index<'a>,
+    /// The index of the array type we're copying from.
+    pub src_array: Index<'a>,
+}
+
+impl<'a> Parse<'a> for ArrayCopy<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(ArrayCopy {
+            dest_array: parser.parse()?,
+            src_array: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `array.init_[data/elem]` instruction
+#[derive(Debug)]
+pub struct ArrayInit<'a> {
+    /// The index of the array type we're initializing.
+    pub array: Index<'a>,
+    /// The index of the data or elem segment we're reading from.
+    pub segment: Index<'a>,
+}
+
+impl<'a> Parse<'a> for ArrayInit<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(ArrayInit {
+            array: parser.parse()?,
+            segment: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `array.new_fixed` instruction
+#[derive(Debug)]
+pub struct ArrayNewFixed<'a> {
+    /// The index of the array type we're accessing.
+    pub array: Index<'a>,
+    /// The amount of values to initialize the array with.
+    pub length: u32,
+}
+
+impl<'a> Parse<'a> for ArrayNewFixed<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(ArrayNewFixed {
+            array: parser.parse()?,
+            length: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `array.new_data` instruction
+#[derive(Debug)]
+pub struct ArrayNewData<'a> {
+    /// The index of the array type we're accessing.
+    pub array: Index<'a>,
+    /// The data segment to initialize from.
+    pub data_idx: Index<'a>,
+}
+
+impl<'a> Parse<'a> for ArrayNewData<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(ArrayNewData {
+            array: parser.parse()?,
+            data_idx: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `array.new_elem` instruction
+#[derive(Debug)]
+pub struct ArrayNewElem<'a> {
+    /// The index of the array type we're accessing.
+    pub array: Index<'a>,
+    /// The elem segment to initialize from.
+    pub elem_idx: Index<'a>,
+}
+
+impl<'a> Parse<'a> for ArrayNewElem<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(ArrayNewElem {
+            array: parser.parse()?,
+            elem_idx: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `ref.cast` instruction
+#[derive(Debug)]
+pub struct RefCast<'a> {
+    /// The type to cast to.
+    pub r#type: RefType<'a>,
+}
+
+impl<'a> Parse<'a> for RefCast<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(RefCast {
+            r#type: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `ref.test` instruction
+#[derive(Debug)]
+pub struct RefTest<'a> {
+    /// The type to test for.
+    pub r#type: RefType<'a>,
+}
+
+impl<'a> Parse<'a> for RefTest<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(RefTest {
+            r#type: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `br_on_cast` instruction
+#[derive(Debug)]
+pub struct BrOnCast<'a> {
+    /// The label to branch to.
+    pub label: Index<'a>,
+    /// The type we're casting from.
+    pub from_type: RefType<'a>,
+    /// The type we're casting to.
+    pub to_type: RefType<'a>,
+}
+
+impl<'a> Parse<'a> for BrOnCast<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(BrOnCast {
+            label: parser.parse()?,
+            from_type: parser.parse()?,
+            to_type: parser.parse()?,
+        })
+    }
+}
+
+/// Extra data associated with the `br_on_cast_fail` instruction
+#[derive(Debug)]
+pub struct BrOnCastFail<'a> {
+    /// The label to branch to.
+    pub label: Index<'a>,
+    /// The type we're casting from.
+    pub from_type: RefType<'a>,
+    /// The type we're casting to.
+    pub to_type: RefType<'a>,
+}
+
+impl<'a> Parse<'a> for BrOnCastFail<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(BrOnCastFail {
+            label: parser.parse()?,
+            from_type: parser.parse()?,
+            to_type: parser.parse()?,
+        })
+    }
+}
+
+/// Different ways to specify a `v128.const` instruction
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub enum V128Const {
+    I8x16([i8; 16]),
+    I16x8([i16; 8]),
+    I32x4([i32; 4]),
+    I64x2([i64; 2]),
+    F32x4([Float32; 4]),
+    F64x2([Float64; 2]),
+}
+
+impl V128Const {
+    /// Returns the raw little-ended byte sequence used to represent this
+    /// `v128` constant`
+    ///
+    /// This is typically suitable for encoding as the payload of the
+    /// `v128.const` instruction.
+    #[rustfmt::skip]
+    pub fn to_le_bytes(&self) -> [u8; 16] {
+        match self {
+            V128Const::I8x16(arr) => [
+                arr[0] as u8,
+                arr[1] as u8,
+                arr[2] as u8,
+                arr[3] as u8,
+                arr[4] as u8,
+                arr[5] as u8,
+                arr[6] as u8,
+                arr[7] as u8,
+                arr[8] as u8,
+                arr[9] as u8,
+                arr[10] as u8,
+                arr[11] as u8,
+                arr[12] as u8,
+                arr[13] as u8,
+                arr[14] as u8,
+                arr[15] as u8,
+            ],
+            V128Const::I16x8(arr) => {
+                let a1 = arr[0].to_le_bytes();
+                let a2 = arr[1].to_le_bytes();
+                let a3 = arr[2].to_le_bytes();
+                let a4 = arr[3].to_le_bytes();
+                let a5 = arr[4].to_le_bytes();
+                let a6 = arr[5].to_le_bytes();
+                let a7 = arr[6].to_le_bytes();
+                let a8 = arr[7].to_le_bytes();
+                [
+                    a1[0], a1[1],
+                    a2[0], a2[1],
+                    a3[0], a3[1],
+                    a4[0], a4[1],
+                    a5[0], a5[1],
+                    a6[0], a6[1],
+                    a7[0], a7[1],
+                    a8[0], a8[1],
+                ]
+            }
+            V128Const::I32x4(arr) => {
+                let a1 = arr[0].to_le_bytes();
+                let a2 = arr[1].to_le_bytes();
+                let a3 = arr[2].to_le_bytes();
+                let a4 = arr[3].to_le_bytes();
+                [
+                    a1[0], a1[1], a1[2], a1[3],
+                    a2[0], a2[1], a2[2], a2[3],
+                    a3[0], a3[1], a3[2], a3[3],
+                    a4[0], a4[1], a4[2], a4[3],
+                ]
+            }
+            V128Const::I64x2(arr) => {
+                let a1 = arr[0].to_le_bytes();
+                let a2 = arr[1].to_le_bytes();
+                [
+                    a1[0], a1[1], a1[2], a1[3], a1[4], a1[5], a1[6], a1[7],
+                    a2[0], a2[1], a2[2], a2[3], a2[4], a2[5], a2[6], a2[7],
+                ]
+            }
+            V128Const::F32x4(arr) => {
+                let a1 = arr[0].bits.to_le_bytes();
+                let a2 = arr[1].bits.to_le_bytes();
+                let a3 = arr[2].bits.to_le_bytes();
+                let a4 = arr[3].bits.to_le_bytes();
+                [
+                    a1[0], a1[1], a1[2], a1[3],
+                    a2[0], a2[1], a2[2], a2[3],
+                    a3[0], a3[1], a3[2], a3[3],
+                    a4[0], a4[1], a4[2], a4[3],
+                ]
+            }
+            V128Const::F64x2(arr) => {
+                let a1 = arr[0].bits.to_le_bytes();
+                let a2 = arr[1].bits.to_le_bytes();
+                [
+                    a1[0], a1[1], a1[2], a1[3], a1[4], a1[5], a1[6], a1[7],
+                    a2[0], a2[1], a2[2], a2[3], a2[4], a2[5], a2[6], a2[7],
+                ]
+            }
+        }
+    }
+}
+
+impl<'a> Parse<'a> for V128Const {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<kw::i8x16>()? {
+            parser.parse::<kw::i8x16>()?;
+            Ok(V128Const::I8x16([
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+            ]))
+        } else if l.peek::<kw::i16x8>()? {
+            parser.parse::<kw::i16x8>()?;
+            Ok(V128Const::I16x8([
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+            ]))
+        } else if l.peek::<kw::i32x4>()? {
+            parser.parse::<kw::i32x4>()?;
+            Ok(V128Const::I32x4([
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+            ]))
+        } else if l.peek::<kw::i64x2>()? {
+            parser.parse::<kw::i64x2>()?;
+            Ok(V128Const::I64x2([parser.parse()?, parser.parse()?]))
+        } else if l.peek::<kw::f32x4>()? {
+            parser.parse::<kw::f32x4>()?;
+            Ok(V128Const::F32x4([
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+            ]))
+        } else if l.peek::<kw::f64x2>()? {
+            parser.parse::<kw::f64x2>()?;
+            Ok(V128Const::F64x2([parser.parse()?, parser.parse()?]))
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+/// Lanes being shuffled in the `i8x16.shuffle` instruction
+#[derive(Debug)]
+pub struct I8x16Shuffle {
+    #[allow(missing_docs)]
+    pub lanes: [u8; 16],
+}
+
+impl<'a> Parse<'a> for I8x16Shuffle {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        Ok(I8x16Shuffle {
+            lanes: [
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+                parser.parse()?,
+            ],
+        })
+    }
+}
+
+/// Payload of the `select` instructions
+#[derive(Debug)]
+pub struct SelectTypes<'a> {
+    #[allow(missing_docs)]
+    pub tys: Option<Vec<ValType<'a>>>,
+}
+
+impl<'a> Parse<'a> for SelectTypes<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut found = false;
+        let mut list = Vec::new();
+        while parser.peek2::<kw::result>()? {
+            found = true;
+            parser.parens(|p| {
+                p.parse::<kw::result>()?;
+                while !p.is_empty() {
+                    list.push(p.parse()?);
+                }
+                Ok(())
+            })?;
+        }
+        Ok(SelectTypes {
+            tys: if found { Some(list) } else { None },
+        })
+    }
+}