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use std::collections::HashMap;
use std::iter::repeat;
use std::sync::{Arc, Weak};
use elements::{Module, InitExpr, Opcode, Type, FunctionType, FuncBody, Internal, External, BlockType, ResizableLimits};
use interpreter::Error;
use interpreter::imports::ModuleImports;
use interpreter::memory::MemoryInstance;
use interpreter::program::ProgramInstanceEssence;
use interpreter::runner::{Interpreter, FunctionContext};
use interpreter::stack::StackWithLimit;
use interpreter::table::TableInstance;
use interpreter::validator::{Validator, FunctionValidationContext};
use interpreter::value::{RuntimeValue, TryInto};
use interpreter::variable::{VariableInstance, VariableType};
const DEFAULT_VALUE_STACK_LIMIT: usize = 16384;
const DEFAULT_FRAME_STACK_LIMIT: usize = 128;
#[derive(Default, Clone)]
pub struct ExecutionParams<'a> {
pub args: Vec<RuntimeValue>,
pub externals: HashMap<String, Arc<ModuleInstanceInterface + 'a>>,
}
#[derive(Debug, Clone)]
pub enum ExportEntryType {
Any,
Function(FunctionType),
Global(VariableType),
}
pub trait ModuleInstanceInterface {
fn instantiate<'a>(&self, is_user_module: bool, externals: Option<&'a HashMap<String, Arc<ModuleInstanceInterface + 'a>>>) -> Result<(), Error>;
fn execute_index(&self, index: u32, params: ExecutionParams) -> Result<Option<RuntimeValue>, Error>;
fn execute_export(&self, name: &str, params: ExecutionParams) -> Result<Option<RuntimeValue>, Error>;
fn export_entry<'a>(&self, name: &str, externals: Option<&'a HashMap<String, Arc<ModuleInstanceInterface + 'a>>>, required_type: &ExportEntryType) -> Result<Internal, Error>;
fn function_type<'a>(&self, function_index: ItemIndex, externals: Option<&'a HashMap<String, Arc<ModuleInstanceInterface + 'a>>>) -> Result<FunctionType, Error>;
fn table(&self, index: ItemIndex) -> Result<Arc<TableInstance>, Error>;
fn memory(&self, index: ItemIndex) -> Result<Arc<MemoryInstance>, Error>;
fn global(&self, index: ItemIndex, variable_type: Option<VariableType>) -> Result<Arc<VariableInstance>, Error>;
fn call_function(&self, outer: CallerContext, index: ItemIndex, function_type: Option<&FunctionType>) -> Result<Option<RuntimeValue>, Error>;
fn call_function_indirect(&self, outer: CallerContext, table_index: ItemIndex, type_index: u32, func_index: u32) -> Result<Option<RuntimeValue>, Error>;
fn call_internal_function(&self, outer: CallerContext, index: u32, function_type: Option<&FunctionType>) -> Result<Option<RuntimeValue>, Error>;
}
#[derive(Debug, Clone, Copy)]
pub enum ItemIndex {
IndexSpace(u32),
Internal(u32),
External(u32),
}
pub struct ModuleInstance {
name: String,
module: Module,
imports: ModuleImports,
tables: Vec<Arc<TableInstance>>,
memory: Vec<Arc<MemoryInstance>>,
globals: Vec<Arc<VariableInstance>>,
}
pub struct CallerContext<'a> {
pub value_stack_limit: usize,
pub frame_stack_limit: usize,
pub value_stack: &'a mut StackWithLimit<RuntimeValue>,
pub externals: &'a HashMap<String, Arc<ModuleInstanceInterface + 'a>>,
}
impl<'a> ExecutionParams<'a> {
pub fn with_external(name: String, module: Arc<ModuleInstanceInterface + 'a>) -> Self {
let mut externals = HashMap::new();
externals.insert(name, module);
ExecutionParams {
args: Vec::new(),
externals: externals,
}
}
pub fn add_argument(mut self, arg: RuntimeValue) -> Self {
self.args.push(arg);
self
}
}
impl<'a> From<Vec<RuntimeValue>> for ExecutionParams<'a> {
fn from(args: Vec<RuntimeValue>) -> ExecutionParams<'a> {
ExecutionParams {
args: args,
externals: HashMap::new(),
}
}
}
impl ModuleInstance {
pub fn new<'a>(program: Weak<ProgramInstanceEssence>, name: String, module: Module) -> Result<Self, Error> {
let imports = ModuleImports::new(program, module.import_section());
let memory = match module.memory_section() {
Some(memory_section) => memory_section.entries()
.iter()
.map(MemoryInstance::new)
.collect::<Result<Vec<_>, _>>()?,
None => Vec::new(),
};
let tables = match module.table_section() {
Some(table_section) => table_section.entries()
.iter()
.map(|tt| TableInstance::new(VariableType::AnyFunc, tt))
.collect::<Result<Vec<_>, _>>()?,
None => Vec::new(),
};
let globals = match module.global_section() {
Some(global_section) => global_section.entries()
.iter()
.map(|g| {
get_initializer(g.init_expr(), &module, &imports, g.global_type().content_type().into())
.map_err(|e| Error::Initialization(e.into()))
.and_then(|v| VariableInstance::new_global(g.global_type(), v).map(Arc::new))
})
.collect::<Result<Vec<_>, _>>()?,
None => Vec::new(),
};
Ok(ModuleInstance {
name: name,
module: module,
imports: imports,
memory: memory,
tables: tables,
globals: globals,
})
}
fn require_function(&self, index: ItemIndex) -> Result<u32, Error> {
match self.imports.parse_function_index(index) {
ItemIndex::IndexSpace(_) => unreachable!("parse_function_index resolves IndexSpace option"),
ItemIndex::Internal(index) => self.module.function_section()
.ok_or(Error::Function(format!("missing internal function {}", index)))
.and_then(|s| s.entries().get(index as usize)
.ok_or(Error::Function(format!("missing internal function {}", index))))
.map(|f| f.type_ref()),
ItemIndex::External(index) => self.module.import_section()
.ok_or(Error::Function(format!("missing external function {}", index)))
.and_then(|s| s.entries().get(index as usize)
.ok_or(Error::Function(format!("missing external function {}", index))))
.and_then(|import| match import.external() {
&External::Function(type_idx) => Ok(type_idx),
_ => Err(Error::Function(format!("external function {} is pointing to non-function import", index))),
}),
}
}
fn require_function_type(&self, type_index: u32) -> Result<&FunctionType, Error> {
self.module.type_section()
.ok_or(Error::Validation(format!("type reference {} exists in module without type section", type_index)))
.and_then(|s| match s.types().get(type_index as usize) {
Some(&Type::Function(ref function_type)) => Ok(function_type),
_ => Err(Error::Validation(format!("missing function type with index {}", type_index))),
})
}
}
impl ModuleInstanceInterface for ModuleInstance {
fn instantiate<'a>(&self, is_user_module: bool, externals: Option<&'a HashMap<String, Arc<ModuleInstanceInterface + 'a>>>) -> Result<(), Error> {
if let Some(start_function) = self.module.start_section() {
let func_type_index = self.require_function(ItemIndex::IndexSpace(start_function))?;
if is_user_module {
let func_type = self.require_function_type(func_type_index)?;
if func_type.return_type() != None || func_type.params().len() != 0 {
return Err(Error::Validation("start function expected to have type [] -> []".into()));
}
}
}
if is_user_module {
if let Some(export_section) = self.module.export_section() {
for export in export_section.entries() {
match export.internal() {
&Internal::Function(function_index) =>
self.require_function(ItemIndex::IndexSpace(function_index)).map(|_| ())?,
&Internal::Global(global_index) =>
self.global(ItemIndex::IndexSpace(global_index), None)
.and_then(|g| if g.is_mutable() {
Err(Error::Validation(format!("trying to export mutable global {}", export.field())))
} else {
Ok(())
})?,
&Internal::Memory(memory_index) =>
self.memory(ItemIndex::IndexSpace(memory_index)).map(|_| ())?,
&Internal::Table(table_index) =>
self.table(ItemIndex::IndexSpace(table_index)).map(|_| ())?,
}
}
}
}
if let Some(import_section) = self.module.import_section() {
for import in import_section.entries() {
match import.external() {
&External::Function(ref function_type_index) => {
let import_function_type = self.require_function_type(*function_type_index)?;
let external_module = self.imports.module(externals, import.module())?;
let export_entry = external_module.export_entry(import.field(), externals, &ExportEntryType::Function(import_function_type.clone()))?;
let export_function_type = match export_entry {
Internal::Function(function_index) => external_module.function_type(ItemIndex::IndexSpace(function_index), externals)?,
_ => return Err(Error::Validation(format!("Export with name {} from module {} is not a function", import.field(), import.module()))),
};
if import_function_type != &export_function_type {
return Err(Error::Validation(format!("Export function type {} mismatch. Expected function with signature ({:?}) -> {:?} when got with ({:?}) -> {:?}",
function_type_index, import_function_type.params(), import_function_type.return_type(),
export_function_type.params(), export_function_type.return_type())));
}
},
&External::Global(ref global_type) => if global_type.is_mutable() {
return Err(Error::Validation(format!("trying to import mutable global {}", import.field())));
} else {
self.imports.global(externals, import, Some(global_type.content_type().into()))?;
},
&External::Memory(ref memory_type) => {
check_limits(memory_type.limits())?;
self.imports.memory(externals, import)?;
},
&External::Table(ref table_type) => {
check_limits(table_type.limits())?;
self.imports.table(externals, import)?;
},
}
}
}
if self.imports.tables_len() + self.tables.len() > 1 {
return Err(Error::Validation(format!("too many tables in index space: {}", self.imports.tables_len() + self.tables.len())));
}
if self.imports.memory_regions_len() + self.memory.len() > 1 {
return Err(Error::Validation(format!("too many memory regions in index space: {}", self.imports.memory_regions_len() + self.memory.len())));
}
let function_section_len = self.module.function_section().map(|s| s.entries().len()).unwrap_or(0);
let code_section_len = self.module.code_section().map(|s| s.bodies().len()).unwrap_or(0);
if function_section_len != code_section_len {
return Err(Error::Validation(format!("length of function section is {}, while len of code section is {}", function_section_len, code_section_len)));
}
if is_user_module && function_section_len != 0 {
let function_section = self.module.function_section().expect("function_section_len != 0; qed");
let code_section = self.module.code_section().expect("function_section_len != 0; function_section_len == code_section_len; qed");
for (index, function) in function_section.entries().iter().enumerate() {
let function_type = self.require_function_type(function.type_ref())?;
let function_body = code_section.bodies().get(index as usize).ok_or(Error::Validation(format!("Missing body for function {}", index)))?;
let mut locals = function_type.params().to_vec();
locals.extend(function_body.locals().iter().flat_map(|l| repeat(l.value_type()).take(l.count() as usize)));
let mut context = FunctionValidationContext::new(
&self.module,
&self.imports,
&locals,
DEFAULT_VALUE_STACK_LIMIT,
DEFAULT_FRAME_STACK_LIMIT,
&function_type);
let block_type = function_type.return_type().map(BlockType::Value).unwrap_or(BlockType::NoResult);
Validator::validate_block(&mut context, false, block_type, function_body.code().elements(), Opcode::End)
.map_err(|e| {
if let Error::Validation(msg) = e {
Error::Validation(format!("Function #{} validation error: {}", index, msg))
} else {
e
}
})?;
}
}
if let Some(data_section) = self.module.data_section() {
for (data_segment_index, data_segment) in data_section.entries().iter().enumerate() {
let offset: u32 = get_initializer(data_segment.offset(), &self.module, &self.imports, VariableType::I32)?.try_into()?;
self.memory(ItemIndex::IndexSpace(data_segment.index()))
.map_err(|e| Error::Initialization(format!("DataSegment {} initializes non-existant MemoryInstance {}: {:?}", data_segment_index, data_segment.index(), e)))
.and_then(|m| m.set(offset, data_segment.value()))
.map_err(|e| Error::Initialization(e.into()))?;
}
}
if let Some(element_section) = self.module.elements_section() {
for (element_segment_index, element_segment) in element_section.entries().iter().enumerate() {
let offset: u32 = get_initializer(element_segment.offset(), &self.module, &self.imports, VariableType::I32)?.try_into()?;
for function_index in element_segment.members() {
self.require_function(ItemIndex::IndexSpace(*function_index))?;
}
self.table(ItemIndex::IndexSpace(element_segment.index()))
.map_err(|e| Error::Initialization(format!("ElementSegment {} initializes non-existant Table {}: {:?}", element_segment_index, element_segment.index(), e)))
.and_then(|m| m.set_raw(offset, self.name.clone(), element_segment.members()))
.map_err(|e| Error::Initialization(e.into()))?;
}
}
if let Some(start_function) = self.module.start_section() {
self.execute_index(start_function, ExecutionParams::default())?;
}
Ok(())
}
fn execute_index(&self, index: u32, params: ExecutionParams) -> Result<Option<RuntimeValue>, Error> {
let args_len = params.args.len();
let mut args = StackWithLimit::with_data(params.args, args_len);
let caller_context = CallerContext::topmost(&mut args, ¶ms.externals);
self.call_function(caller_context, ItemIndex::IndexSpace(index), None)
}
fn execute_export(&self, name: &str, params: ExecutionParams) -> Result<Option<RuntimeValue>, Error> {
let index = self.module.export_section()
.ok_or(Error::Function("missing export section".into()))
.and_then(|s| s.entries().iter()
.find(|e| e.field() == name && match e.internal() {
&Internal::Function(_) => true,
_ => false,
})
.ok_or(Error::Function(format!("missing export section exported function with name {}", name)))
.map(|e| match e.internal() {
&Internal::Function(index) => index,
_ => unreachable!(),
})
)?;
self.execute_index(index, params)
}
fn export_entry<'a>(&self, name: &str, externals: Option<&'a HashMap<String, Arc<ModuleInstanceInterface + 'a>>>, required_type: &ExportEntryType) -> Result<Internal, Error> {
self.module.export_section()
.ok_or(Error::Program(format!("trying to import {} from module without export section", name)))
.and_then(|s| s.entries().iter()
.find(|e| e.field() == name && match required_type {
&ExportEntryType::Any => true,
&ExportEntryType::Global(global_type) => match e.internal() {
&Internal::Global(global_index) => self.global(ItemIndex::IndexSpace(global_index), Some(global_type)).map(|_| true).unwrap_or(false),
_ => false,
},
&ExportEntryType::Function(ref required_type) => match e.internal() {
&Internal::Function(function_index) =>
self.function_type(ItemIndex::IndexSpace(function_index), externals)
.map(|ft| &ft == required_type)
.unwrap_or(false),
_ => false,
},
})
.map(|e| *e.internal())
.ok_or(Error::Program(format!("unresolved import {}", name))))
}
fn function_type<'a>(&self, function_index: ItemIndex, externals: Option<&'a HashMap<String, Arc<ModuleInstanceInterface + 'a>>>) -> Result<FunctionType, Error> {
match self.imports.parse_function_index(function_index) {
ItemIndex::IndexSpace(_) => unreachable!("parse_function_index resolves IndexSpace option"),
ItemIndex::Internal(index) => self.require_function(ItemIndex::Internal(index))
.and_then(|ft| self.require_function_type(ft).map(Clone::clone)),
ItemIndex::External(index) => self.module.import_section()
.ok_or(Error::Function(format!("trying to access external function with index {} in module without import section", index)))
.and_then(|s| s.entries().get(index as usize)
.ok_or(Error::Function(format!("trying to access external function with index {} in module with {}-entries import section", index, s.entries().len()))))
.and_then(|e| self.imports.module(externals, e.module()))
.and_then(|m| m.function_type(ItemIndex::IndexSpace(index), externals)),
}
}
fn table(&self, index: ItemIndex) -> Result<Arc<TableInstance>, Error> {
match self.imports.parse_table_index(index) {
ItemIndex::IndexSpace(_) => unreachable!("parse_table_index resolves IndexSpace option"),
ItemIndex::Internal(index) => self.tables.get(index as usize).cloned()
.ok_or(Error::Table(format!("trying to access table with local index {} when there are only {} local tables", index, self.tables.len()))),
ItemIndex::External(index) => self.module.import_section()
.ok_or(Error::Table(format!("trying to access external table with index {} in module without import section", index)))
.and_then(|s| s.entries().get(index as usize)
.ok_or(Error::Table(format!("trying to access external table with index {} in module with {}-entries import section", index, s.entries().len()))))
.and_then(|e| self.imports.table(None, e)),
}
}
fn memory(&self, index: ItemIndex) -> Result<Arc<MemoryInstance>, Error> {
match self.imports.parse_memory_index(index) {
ItemIndex::IndexSpace(_) => unreachable!("parse_memory_index resolves IndexSpace option"),
ItemIndex::Internal(index) => self.memory.get(index as usize).cloned()
.ok_or(Error::Memory(format!("trying to access memory with local index {} when there are only {} memory regions", index, self.memory.len()))),
ItemIndex::External(index) => self.module.import_section()
.ok_or(Error::Memory(format!("trying to access external memory with index {} in module without import section", index)))
.and_then(|s| s.entries().get(index as usize)
.ok_or(Error::Memory(format!("trying to access external memory with index {} in module with {}-entries import section", index, s.entries().len()))))
.and_then(|e| self.imports.memory(None, e)),
}
}
fn global(&self, index: ItemIndex, variable_type: Option<VariableType>) -> Result<Arc<VariableInstance>, Error> {
match self.imports.parse_global_index(index) {
ItemIndex::IndexSpace(_) => unreachable!("parse_global_index resolves IndexSpace option"),
ItemIndex::Internal(index) => self.globals.get(index as usize).cloned()
.ok_or(Error::Global(format!("trying to access global with local index {} when there are only {} globals", index, self.globals.len()))),
ItemIndex::External(index) => self.module.import_section()
.ok_or(Error::Global(format!("trying to access external global with index {} in module without import section", index)))
.and_then(|s| s.entries().get(index as usize)
.ok_or(Error::Global(format!("trying to access external global with index {} in module with {}-entries import section", index, s.entries().len()))))
.and_then(|e| self.imports.global(None, e, variable_type)),
}
}
fn call_function(&self, outer: CallerContext, index: ItemIndex, function_type: Option<&FunctionType>) -> Result<Option<RuntimeValue>, Error> {
match self.imports.parse_function_index(index) {
ItemIndex::IndexSpace(_) => unreachable!("parse_function_index resolves IndexSpace option"),
ItemIndex::Internal(index) => self.call_internal_function(outer, index, function_type),
ItemIndex::External(index) => self.module.import_section()
.ok_or(Error::Function(format!("trying to access external function with index {} in module without import section", index)))
.and_then(|s| s.entries().get(index as usize)
.ok_or(Error::Function(format!("trying to access external function with index {} in module with {}-entries import section", index, s.entries().len()))))
.and_then(|e| Ok((self.imports.module(Some(outer.externals), e.module())?,
self.imports.function(Some(outer.externals), e, function_type)?)))
.and_then(|(m, index)| m.call_internal_function(outer, index, function_type)),
}
}
fn call_function_indirect(&self, outer: CallerContext, table_index: ItemIndex, type_index: u32, func_index: u32) -> Result<Option<RuntimeValue>, Error> {
let function_type = match self.module.type_section()
.ok_or(Error::Function(format!("trying to indirect call function {} with non-existent function section", func_index)))
.and_then(|s| s.types().get(type_index as usize)
.ok_or(Error::Function(format!("trying to indirect call function {} with non-existent type index {}", func_index, type_index))))? {
&Type::Function(ref function_type) => function_type,
};
let table = self.table(table_index)?;
let (module, index) = match table.get(func_index)? {
RuntimeValue::AnyFunc(module, index) => (module.clone(), index),
_ => return Err(Error::Function(format!("trying to indirect call function {} via non-anyfunc table {:?}", func_index, table_index))),
};
let module = self.imports.module(Some(outer.externals), &module)?;
module.call_function(outer, ItemIndex::IndexSpace(index), Some(function_type))
}
fn call_internal_function(&self, mut outer: CallerContext, index: u32, function_type: Option<&FunctionType>) -> Result<Option<RuntimeValue>, Error> {
let function_type_index = self.module
.function_section()
.ok_or(Error::Function(format!("trying to call function with index {} in module without function section", index)))
.and_then(|s| s.entries()
.get(index as usize)
.ok_or(Error::Function(format!("trying to call function with index {} in module with {} functions", index, s.entries().len()))))?
.type_ref();
let item_type = self.module
.type_section()
.ok_or(Error::Function(format!("trying to call function with index {} in module without types section", index)))
.and_then(|s| s.types()
.get(function_type_index as usize)
.ok_or(Error::Function(format!("trying to call function with type index {} in module with {} types", function_type_index, s.types().len()))))?;
let actual_function_type = match item_type {
&Type::Function(ref function_type) => function_type,
};
if let Some(ref function_type) = function_type {
if function_type != &actual_function_type {
return Err(Error::Function(format!("expected function with signature ({:?}) -> {:?} when got with ({:?}) -> {:?}",
function_type.params(), function_type.return_type(), actual_function_type.params(), actual_function_type.return_type())));
}
}
let function_body = self.module
.code_section()
.ok_or(Error::Function(format!("trying to call function with index {} in module without code section", index)))
.and_then(|s| s.bodies()
.get(index as usize)
.ok_or(Error::Function(format!("trying to call function with index {} in module with {} functions codes", index, s.bodies().len()))))?;
let function_code = function_body.code().elements();
let value_stack_limit = outer.value_stack_limit;
let frame_stack_limit = outer.frame_stack_limit;
let locals = prepare_function_locals(actual_function_type, function_body, &mut outer)?;
let mut innner = FunctionContext::new(self, outer.externals, value_stack_limit, frame_stack_limit, actual_function_type, locals);
Interpreter::run_function(&mut innner, function_code)
}
}
impl<'a> CallerContext<'a> {
pub fn topmost(args: &'a mut StackWithLimit<RuntimeValue>, externals: &'a HashMap<String, Arc<ModuleInstanceInterface + 'a>>) -> Self {
CallerContext {
value_stack_limit: DEFAULT_VALUE_STACK_LIMIT,
frame_stack_limit: DEFAULT_FRAME_STACK_LIMIT,
value_stack: args,
externals: externals,
}
}
pub fn nested(outer: &'a mut FunctionContext) -> Self {
CallerContext {
value_stack_limit: outer.value_stack().limit() - outer.value_stack().len(),
frame_stack_limit: outer.frame_stack().limit() - outer.frame_stack().len(),
value_stack: &mut outer.value_stack,
externals: &outer.externals,
}
}
}
pub fn check_limits(limits: &ResizableLimits) -> Result<(), Error> {
if let Some(maximum) = limits.maximum() {
if maximum < limits.initial() {
return Err(Error::Validation(format!("maximum limit {} is lesser than minimum {}", maximum, limits.initial())));
}
}
Ok(())
}
fn prepare_function_locals(function_type: &FunctionType, function_body: &FuncBody, outer: &mut CallerContext) -> Result<Vec<VariableInstance>, Error> {
function_type.params().iter().rev()
.map(|param_type| {
let param_value = outer.value_stack.pop()?;
let actual_type = param_value.variable_type();
let expected_type = (*param_type).into();
if actual_type != Some(expected_type) {
return Err(Error::Function(format!("invalid parameter type {:?} when expected {:?}", actual_type, expected_type)));
}
VariableInstance::new(true, expected_type, param_value)
})
.collect::<Vec<_>>().into_iter().rev()
.chain(function_body.locals()
.iter()
.flat_map(|l| repeat(l.value_type().into()).take(l.count() as usize))
.map(|vt| VariableInstance::new(true, vt, RuntimeValue::default(vt))))
.collect::<Result<Vec<_>, _>>()
}
fn get_initializer(expr: &InitExpr, module: &Module, imports: &ModuleImports, expected_type: VariableType) -> Result<RuntimeValue, Error> {
let first_opcode = match expr.code().len() {
1 => &expr.code()[0],
2 if expr.code().len() == 2 && expr.code()[1] == Opcode::End => &expr.code()[0],
_ => return Err(Error::Initialization(format!("expected 1-instruction len initializer. Got {:?}", expr.code()))),
};
match first_opcode {
&Opcode::GetGlobal(index) => {
let index = match imports.parse_global_index(ItemIndex::IndexSpace(index)) {
ItemIndex::External(index) => index,
_ => return Err(Error::Global(format!("trying to initialize with non-external global {}", index))),
};
module.import_section()
.ok_or(Error::Global(format!("trying to initialize with external global with index {} in module without import section", index)))
.and_then(|s| s.entries().get(index as usize)
.ok_or(Error::Global(format!("trying to initialize with external global with index {} in module with {}-entries import section", index, s.entries().len()))))
.and_then(|e| imports.global(None, e, Some(expected_type)))
.map(|g| g.get())
},
&Opcode::I32Const(val) => Ok(RuntimeValue::I32(val)),
&Opcode::I64Const(val) => Ok(RuntimeValue::I64(val)),
&Opcode::F32Const(val) => Ok(RuntimeValue::decode_f32(val)),
&Opcode::F64Const(val) => Ok(RuntimeValue::decode_f64(val)),
_ => Err(Error::Initialization(format!("not-supported {:?} instruction in instantiation-time initializer", first_opcode))),
}
}