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add fuel metering to call, table, memory and global instructions
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@Robbepop
Robbepop committed Nov 28, 2023
1 parent 3414b63 commit 99d094a
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Showing 2 changed files with 68 additions and 67 deletions.
22 changes: 22 additions & 0 deletions crates/wasmi/src/engine/regmach/translator/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -329,6 +329,28 @@ impl<'parser> FuncTranslator<'parser> {
Ok(())
}

/// Utility function for pushing a new [`Instruction`] with fuel costs.
///
/// # Note
///
/// Fuel metering is only encoded or adjusted if it is enabled.
fn push_fueled_instr<F>(&mut self, instr: Instruction, f: F) -> Result<Instr, TranslationError>
where
F: FnOnce(&FuelCosts) -> u64,
{
self.bump_fuel_consumption(f)?;
self.alloc.instr_encoder.push_instr(instr)
}

/// Utility function for pushing a new [`Instruction`] with basic fuel costs.
///
/// # Note
///
/// Fuel metering is only encoded or adjusted if it is enabled.
fn push_base_instr(&mut self, instr: Instruction) -> Result<Instr, TranslationError> {
self.push_fueled_instr(instr, FuelCosts::base)
}

/// Convenience function to copy the parameters when branching to a control frame.
fn translate_copy_branch_params(
&mut self,
Expand Down
113 changes: 46 additions & 67 deletions crates/wasmi/src/engine/regmach/translator/visit.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -97,9 +97,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {

fn visit_unreachable(&mut self) -> Self::Output {
bail_unreachable!(self);
self.alloc
.instr_encoder
.push_instr(Instruction::Trap(TrapCode::UnreachableCodeReached))?;
self.push_base_instr(Instruction::Trap(TrapCode::UnreachableCodeReached))?;
self.reachable = false;
Ok(())
}
Expand Down Expand Up @@ -301,9 +299,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
.try_resolve_label(frame.end_label())?;
// We are jumping to the end of the `if` so technically we need to bump branches.
frame.bump_branches();
self.alloc
.instr_encoder
.push_instr(Instruction::branch(end_offset))?;
self.push_base_instr(Instruction::branch(end_offset))?;
}
self.reachable = true;
self.alloc.instr_encoder.pin_label(else_label);
Expand Down Expand Up @@ -371,9 +367,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
let branch_params = frame.branch_params(self.res.engine());
self.translate_copy_branch_params(branch_params)?;
let branch_offset = self.alloc.instr_encoder.try_resolve_label(branch_dst)?;
self.alloc
.instr_encoder
.push_instr(Instruction::branch(branch_offset))?;
self.push_base_instr(Instruction::branch(branch_offset))?;
self.reachable = false;
Ok(())
}
Expand Down Expand Up @@ -455,9 +449,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
)?;
let branch_offset =
self.alloc.instr_encoder.try_resolve_label(branch_dst)?;
self.alloc
.instr_encoder
.push_instr(Instruction::branch(branch_offset))?;
self.push_base_instr(Instruction::branch(branch_offset))?;
self.alloc.instr_encoder.pin_label(skip_label);
Ok(())
}
Expand Down Expand Up @@ -532,9 +524,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
// the default branch target and encode the `br_table` with a series of
// simple direct branches without any further copy instructions.
self.translate_copy_branch_params(default_branch_params)?;
self.alloc
.instr_encoder
.push_instr(Instruction::branch_table(index, targets.len() + 1))?;
self.push_base_instr(Instruction::branch_table(index, targets.len() + 1))?;
let return_instr = match default_branch_params.len() {
0 => Instruction::Return,
1 => Instruction::return_reg(default_branch_params.span().head()),
Expand Down Expand Up @@ -566,9 +556,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
//
// Since `br_table` target depths are often shared we use a btree-set to
// share codegen for `br_table` arms that have the same branch target.
self.alloc
.instr_encoder
.push_instr(Instruction::branch_table(index, targets.len() + 1))?;
self.push_base_instr(Instruction::branch_table(index, targets.len() + 1))?;
let mut shared_targets = <BTreeMap<u32, LabelRef>>::new();
for target in self.alloc.br_table_targets.iter().copied() {
let shared_label = *shared_targets
Expand Down Expand Up @@ -598,6 +586,8 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
)?;
let branch_dst = frame.branch_destination();
let branch_offset = self.alloc.instr_encoder.try_resolve_label(branch_dst)?;
// Note: No need to bump fuel consumption for each branch table target
// since only one of the branch targets is going to be executed.
self.alloc
.instr_encoder
.push_instr(Instruction::branch(branch_offset))?;
Expand Down Expand Up @@ -827,9 +817,10 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
// global variable and thus cannot be optimized away.
let global_idx = bytecode::GlobalIdx::from(global_index);
let result = self.alloc.stack.push_dynamic()?;
self.alloc
.instr_encoder
.push_instr(Instruction::global_get(result, global_idx))?;
self.push_fueled_instr(
Instruction::global_get(result, global_idx),
FuelCosts::entity,
)?;
Ok(())
}

Expand All @@ -838,9 +829,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
let global = bytecode::GlobalIdx::from(global_index);
match self.alloc.stack.pop() {
TypedProvider::Register(input) => {
self.alloc
.instr_encoder
.push_instr(Instruction::global_set(global, input))?;
self.push_fueled_instr(Instruction::global_set(global, input), FuelCosts::entity)?;
Ok(())
}
TypedProvider::Const(input) => {
Expand All @@ -850,26 +839,26 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
match global_type.content() {
ValueType::I32 => {
if let Some(value) = Const16::from_i32(i32::from(input)) {
self.alloc
.instr_encoder
.push_instr(Instruction::global_set_i32imm16(global, value))?;
self.push_fueled_instr(
Instruction::global_set_i32imm16(global, value),
FuelCosts::entity,
)?;
return Ok(());
}
}
ValueType::I64 => {
if let Some(value) = Const16::from_i64(i64::from(input)) {
self.alloc
.instr_encoder
.push_instr(Instruction::global_set_i64imm16(global, value))?;
self.push_fueled_instr(
Instruction::global_set_i64imm16(global, value),
FuelCosts::entity,
)?;
return Ok(());
}
}
_ => (),
_ => {}
};
let cref = self.alloc.stack.alloc_const(input)?;
self.alloc
.instr_encoder
.push_instr(Instruction::global_set(global, cref))?;
self.push_fueled_instr(Instruction::global_set(global, cref), FuelCosts::entity)?;
Ok(())
}
}
Expand Down Expand Up @@ -1103,9 +1092,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
);
bail_unreachable!(self);
let result = self.alloc.stack.push_dynamic()?;
self.alloc
.instr_encoder
.push_instr(Instruction::memory_size(result))?;
self.push_fueled_instr(Instruction::memory_size(result), FuelCosts::entity)?;
Ok(())
}

Expand All @@ -1126,7 +1113,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
}
Provider::Const(delta) => Instruction::memory_grow_by(result, delta),
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
Ok(())
}

Expand Down Expand Up @@ -1175,9 +1162,10 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
fn visit_ref_func(&mut self, function_index: u32) -> Self::Output {
bail_unreachable!(self);
let result = self.alloc.stack.push_dynamic()?;
self.alloc
.instr_encoder
.push_instr(Instruction::ref_func(result, function_index))?;
self.push_fueled_instr(
Instruction::ref_func(result, function_index),
FuelCosts::entity,
)?;
Ok(())
}

Expand Down Expand Up @@ -3219,7 +3207,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
Instruction::memory_init_from_to_exact(dst, src, len)
}
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
self.alloc
.instr_encoder
.append_instr(Instruction::data_idx(data_index))?;
Expand All @@ -3228,9 +3216,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {

fn visit_data_drop(&mut self, data_index: u32) -> Self::Output {
bail_unreachable!(self);
self.alloc
.instr_encoder
.push_instr(Instruction::DataDrop(data_index.into()))?;
self.push_fueled_instr(Instruction::DataDrop(data_index.into()), FuelCosts::entity)?;
Ok(())
}

Expand Down Expand Up @@ -3266,7 +3252,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
Instruction::memory_copy_from_to_exact(dst, src, len)
}
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
Ok(())
}

Expand Down Expand Up @@ -3302,7 +3288,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
Instruction::memory_fill_at_imm_exact(dst, value, len)
}
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
Ok(())
}

Expand Down Expand Up @@ -3338,7 +3324,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
Instruction::table_init_from_to_exact(dst, src, len)
}
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
self.alloc
.instr_encoder
.append_instr(Instruction::table_idx(table))?;
Expand All @@ -3350,9 +3336,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {

fn visit_elem_drop(&mut self, elem_index: u32) -> Self::Output {
bail_unreachable!(self);
self.alloc
.instr_encoder
.push_instr(Instruction::ElemDrop(elem_index.into()))?;
self.push_fueled_instr(Instruction::ElemDrop(elem_index.into()), FuelCosts::entity)?;
Ok(())
}

Expand Down Expand Up @@ -3388,7 +3372,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
Instruction::table_copy_from_to_exact(dst, src, len)
}
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
self.alloc
.instr_encoder
.append_instr(Instruction::table_idx(dst_table))?;
Expand Down Expand Up @@ -3421,7 +3405,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
Instruction::table_fill_at_exact(dst, len, value)
}
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
self.alloc
.instr_encoder
.append_instr(Instruction::table_idx(table))?;
Expand All @@ -3434,14 +3418,13 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
let result = self.alloc.stack.push_dynamic()?;
match index {
TypedProvider::Register(index) => {
self.alloc
.instr_encoder
.push_instr(Instruction::table_get(result, index))?;
self.push_fueled_instr(Instruction::table_get(result, index), FuelCosts::entity)?;
}
TypedProvider::Const(index) => {
self.alloc
.instr_encoder
.push_instr(Instruction::table_get_imm(result, u32::from(index)))?;
self.push_fueled_instr(
Instruction::table_get_imm(result, u32::from(index)),
FuelCosts::entity,
)?;
}
}
self.alloc
Expand All @@ -3461,7 +3444,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
TypedProvider::Register(index) => Instruction::table_set(index, value),
TypedProvider::Const(index) => Instruction::table_set_at(u32::from(index), value),
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
self.alloc
.instr_encoder
.append_instr(Instruction::table_idx(table))?;
Expand All @@ -3479,9 +3462,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
// operation a `table.grow` with `delta` of 0 can be translated
// as `table.size` instruction instead.
let result = self.alloc.stack.push_dynamic()?;
self.alloc
.instr_encoder
.push_instr(Instruction::table_size(result, table))?;
self.push_fueled_instr(Instruction::table_size(result, table), FuelCosts::entity)?;
return Ok(());
}
}
Expand All @@ -3495,7 +3476,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
Provider::Register(delta) => Instruction::table_grow(result, delta, value),
Provider::Const(delta) => Instruction::table_grow_imm(result, delta, value),
};
self.alloc.instr_encoder.push_instr(instr)?;
self.push_fueled_instr(instr, FuelCosts::entity)?;
self.alloc
.instr_encoder
.append_instr(Instruction::table_idx(table))?;
Expand All @@ -3505,9 +3486,7 @@ impl<'a> VisitOperator<'a> for FuncTranslator<'a> {
fn visit_table_size(&mut self, table: u32) -> Self::Output {
bail_unreachable!(self);
let result = self.alloc.stack.push_dynamic()?;
self.alloc
.instr_encoder
.push_instr(Instruction::table_size(result, table))?;
self.push_fueled_instr(Instruction::table_size(result, table), FuelCosts::entity)?;
Ok(())
}
}

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