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perf: remove pointer-dereference using owned version of visit_operator #2638

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perf: remove pointer-dereference using owned version of visit_operator #2638

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2 changes: 1 addition & 1 deletion crates/wasmparser/benches/benchmark.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,7 @@ fn read_all_wasm(wasm: &[u8]) -> Result<()> {
let mut ops = OperatorsReader::new_with_allocs(reader, mem::take(&mut allocs));

while !ops.eof() {
ops.visit_operator(&mut NopVisit)?;
ops.visit_operator_owned(NopVisit)?;
}
ops.finish()?;
allocs = ops.into_allocations();
Expand Down
32 changes: 23 additions & 9 deletions crates/wasmparser/src/binary_reader.rs
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Expand Up @@ -828,6 +828,20 @@ impl<'a> BinaryReader<'a> {
/// See the documentation for [`OperatorsReader::visit_operator`] for a version that
/// does not require the visitor to implement [`FrameStack`].
pub fn visit_operator<T>(&mut self, visitor: &mut T) -> Result<<T as VisitOperator<'a>>::Output>
where
T: VisitOperator<'a> + FrameStack,
{
self.visit_operator_owned(visitor)
}

/// Visit the next available operator with the specified [`VisitOperator`] instance
/// that is also a [`FrameStack`].
///
/// Owned (faster) version of [`BinaryReader::visit_operator`], because this one does not use pointer `&mut T`.
pub fn visit_operator_owned<T>(
&mut self,
mut visitor: T,
) -> Result<<T as VisitOperator<'a>>::Output>
where
T: VisitOperator<'a> + FrameStack,
{
Expand All @@ -846,7 +860,7 @@ impl<'a> BinaryReader<'a> {
0x03 => visitor.visit_loop(self.read_block_type()?),
0x04 => visitor.visit_if(self.read_block_type()?),
0x05 => {
self.expect_frame(visitor, FrameKind::If, "else")?;
self.expect_frame(&visitor, FrameKind::If, "else")?;
visitor.visit_else()
}
0x06 => {
Expand All @@ -865,9 +879,9 @@ impl<'a> BinaryReader<'a> {
"legacy_exceptions feature required for catch instruction",
pos,
)?;
match self.expect_frame(visitor, FrameKind::LegacyCatch, "catch") {
match self.expect_frame(&visitor, FrameKind::LegacyCatch, "catch") {
Ok(()) => (),
Err(_) => self.expect_frame(visitor, FrameKind::LegacyTry, "catch")?,
Err(_) => self.expect_frame(&visitor, FrameKind::LegacyTry, "catch")?,
}
visitor.visit_catch(self.read_var_u32()?)
}
Expand All @@ -890,7 +904,7 @@ impl<'a> BinaryReader<'a> {
0x14 => visitor.visit_call_ref(self.read()?),
0x15 => visitor.visit_return_call_ref(self.read()?),
0x18 => {
self.expect_frame(visitor, FrameKind::LegacyTry, "delegate")?;
self.expect_frame(&visitor, FrameKind::LegacyTry, "delegate")?;
visitor.visit_delegate(self.read_var_u32()?)
}
0x19 => {
Expand All @@ -900,9 +914,9 @@ impl<'a> BinaryReader<'a> {
"legacy_exceptions feature required for catch_all instruction",
pos,
)?;
match self.expect_frame(visitor, FrameKind::LegacyCatch, "catch_all") {
match self.expect_frame(&visitor, FrameKind::LegacyCatch, "catch_all") {
Ok(()) => (),
Err(_) => self.expect_frame(visitor, FrameKind::LegacyTry, "catch_all")?,
Err(_) => self.expect_frame(&visitor, FrameKind::LegacyTry, "catch_all")?,
}
visitor.visit_catch_all()
}
Expand Down Expand Up @@ -1134,7 +1148,7 @@ impl<'a> BinaryReader<'a> {
fn visit_0xfb_operator<T>(
&mut self,
pos: u64,
visitor: &mut T,
mut visitor: T,
) -> Result<<T as VisitOperator<'a>>::Output>
where
T: VisitOperator<'a>,
Expand Down Expand Up @@ -1351,7 +1365,7 @@ impl<'a> BinaryReader<'a> {
fn visit_0xfc_operator<T>(
&mut self,
pos: u64,
visitor: &mut T,
mut visitor: T,
) -> Result<<T as VisitOperator<'a>>::Output>
where
T: VisitOperator<'a>,
Expand Down Expand Up @@ -1748,7 +1762,7 @@ impl<'a> BinaryReader<'a> {
fn visit_0xfe_operator<T>(
&mut self,
pos: u64,
visitor: &mut T,
mut visitor: T,
) -> Result<<T as VisitOperator<'a>>::Output>
where
T: VisitOperator<'a>,
Expand Down
37 changes: 28 additions & 9 deletions crates/wasmparser/src/readers/core/operators.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -353,6 +353,12 @@ pub trait FrameStack {
fn current_frame(&self) -> Option<FrameKind>;
}

impl<T: FrameStack> FrameStack for &mut T {
fn current_frame(&self) -> Option<FrameKind> {
(**self).current_frame()
}
}

/// The Wasm control stack for the [`OperatorsReader`].
#[derive(Debug, Default, Clone)]
pub struct ControlStack {
Expand Down Expand Up @@ -398,7 +404,7 @@ impl ControlStack {
/// Adapters from VisitOperators to FrameStacks
struct FrameStackAdapter<'a, T> {
stack: &'a mut ControlStack,
visitor: &'a mut T,
visitor: T,
}

impl<T> FrameStack for FrameStackAdapter<'_, T> {
Expand All @@ -407,12 +413,12 @@ impl<T> FrameStack for FrameStackAdapter<'_, T> {
}
}

struct SingleFrameAdapter<'a, T> {
struct SingleFrameAdapter<T> {
current_frame: FrameKind,
visitor: &'a mut T,
visitor: T,
}

impl<T> FrameStack for SingleFrameAdapter<'_, T> {
impl<T> FrameStack for SingleFrameAdapter<T> {
fn current_frame(&self) -> Option<FrameKind> {
Some(self.current_frame)
}
Expand Down Expand Up @@ -502,7 +508,7 @@ impl<'a> OperatorsReader<'a> {
/// If `OperatorsReader` has less bytes remaining than required to parse
/// the `Operator`, or if the input is malformed.
pub fn read(&mut self) -> Result<Operator<'a>> {
self.visit_operator(&mut OperatorFactory)
self.visit_operator_owned(OperatorFactory)
}

/// Visit the next available operator with the specified [`VisitOperator`] instance.
Expand Down Expand Up @@ -555,7 +561,20 @@ impl<'a> OperatorsReader<'a> {
where
T: VisitOperator<'a>,
{
self.reader.visit_operator(&mut FrameStackAdapter {
self.visit_operator_owned(visitor)
}

/// Visit the next available operator with the specified [`VisitOperator`] instance.
///
/// Owned (faster) version of [`OperatorsReader::visit_operator`], because this one does not use pointer `&mut T`.
pub fn visit_operator_owned<T>(
&mut self,
visitor: T,
) -> Result<<T as VisitOperator<'a>>::Output>
where
T: VisitOperator<'a>,
{
self.reader.visit_operator_owned(FrameStackAdapter {
stack: &mut self.stack,
visitor,
})
Expand Down Expand Up @@ -1085,7 +1104,7 @@ macro_rules! define_passthrough_visit_operator {
};
}

impl<'a, T: VisitOperator<'a>> VisitOperator<'a> for SingleFrameAdapter<'_, T> {
impl<'a, T: VisitOperator<'a>> VisitOperator<'a> for SingleFrameAdapter<T> {
type Output = T::Output;

#[cfg(feature = "simd")]
Expand All @@ -1104,14 +1123,14 @@ impl<'a> BinaryReader<'a> {
/// If `BinaryReader` has less bytes remaining than required to parse
/// the `Operator`, or if the input is malformed.
pub fn peek_operator<T: FrameStack>(&self, stack: &T) -> Result<Operator<'a>> {
self.clone().visit_operator(&mut SingleFrameAdapter {
self.clone().visit_operator_owned(SingleFrameAdapter {
current_frame: stack.current_frame().ok_or_else(|| {
format_err!(
self.original_position(),
"operators remaining after end of function body or expression"
)
})?,
visitor: &mut OperatorFactory,
visitor: OperatorFactory,
})
}
}
2 changes: 1 addition & 1 deletion crates/wasmparser/src/validator/func.rs
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Expand Up @@ -144,7 +144,7 @@ impl<T: WasmModuleResources> FuncValidator<T> {
(reader.clone(), arity)
};

reader.visit_operator(&mut self.visitor(reader.original_position()))??;
reader.visit_operator_owned(self.visitor(reader.original_position()))??;

#[cfg(debug_assertions)]
{
Expand Down
2 changes: 1 addition & 1 deletion crates/wasmprinter/src/operand_stack.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,7 @@ impl FuncValidator {
let pos = reader.original_position();
reader
.clone()
.visit_operator(&mut self.validator.visitor(pos))??;
.visit_operator_owned(self.validator.visitor(pos))??;

if !is_end {
let op = reader.clone().read()?;
Expand Down
5 changes: 2 additions & 3 deletions crates/wasmprinter/src/operator.rs
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Expand Up @@ -1531,9 +1531,8 @@ impl OpPrinter for PrintOperatorFolded<'_, '_, '_, '_> {
code_section_hints: Vec::new(),
};

let mut op_printer =
PrintOperator::new(&mut internal_printer, self.state, self.operator_state);
reader.visit_operator(&mut op_printer)??;
let op_printer = PrintOperator::new(&mut internal_printer, self.state, self.operator_state);
reader.visit_operator_owned(op_printer)??;
if let Some(s) = annotation {
internal_printer.result.start_comment()?;
write!(internal_printer.result, " (; {s}")?;
Expand Down
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