561 lines
13 KiB
Rust
561 lines
13 KiB
Rust
use parity_wasm::elements::{
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BlockType, External, FuncBody, FunctionType, ImportEntry, Instruction, Local, Module, Type,
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};
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use super::{
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node::{
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AnyBinOp, AnyLoad, AnyStore, AnyUnOp, Backward, Br, BrIf, BrTable, Call, CallIndirect,
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Else, Expression, Forward, Function, GetGlobal, GetLocal, If, Memorize, MemoryGrow,
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MemorySize, Recall, Return, Select, SetGlobal, SetLocal, Statement, Value,
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},
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tag::{BinOp, Load, Store, UnOp},
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};
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struct Arity {
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num_param: u32,
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num_result: u32,
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}
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impl Arity {
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fn from_type(typ: &FunctionType) -> Self {
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let num_param = typ.params().len().try_into().unwrap();
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let num_result = typ.results().len().try_into().unwrap();
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Self {
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num_param,
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num_result,
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}
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}
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fn from_index(types: &[Type], index: u32) -> Self {
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let Type::Function(typ) = &types[index as usize];
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Self::from_type(typ)
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}
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fn new_arity_ext(types: &[Type], import: &ImportEntry) -> Option<Arity> {
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if let External::Function(i) = import.external() {
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Some(Arity::from_index(types, *i))
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} else {
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None
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}
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}
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fn new_in_list(wasm: &Module) -> Vec<Self> {
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let (types, funcs) = match (wasm.type_section(), wasm.function_section()) {
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(Some(t), Some(f)) => (t.types(), f.entries()),
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_ => return Vec::new(),
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};
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funcs
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.iter()
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.map(|i| Self::from_index(types, i.type_ref()))
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.collect()
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}
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fn new_ex_list(wasm: &Module) -> Vec<Self> {
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let (types, imports) = match (wasm.type_section(), wasm.import_section()) {
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(Some(t), Some(i)) => (t.types(), i.entries()),
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_ => return Vec::new(),
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};
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imports
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.iter()
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.filter_map(|i| Self::new_arity_ext(types, i))
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.collect()
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}
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}
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pub struct Arities {
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ex_arity: Vec<Arity>,
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in_arity: Vec<Arity>,
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}
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impl Arities {
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pub fn new(parent: &Module) -> Self {
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Self {
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ex_arity: Arity::new_ex_list(parent),
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in_arity: Arity::new_in_list(parent),
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}
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}
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pub fn len_in(&self) -> usize {
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self.in_arity.len()
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}
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pub fn len_ex(&self) -> usize {
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self.ex_arity.len()
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}
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fn arity_of(&self, index: usize) -> &Arity {
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let offset = self.ex_arity.len();
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self.ex_arity
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.get(index)
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.or_else(|| self.in_arity.get(index - offset))
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.unwrap()
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}
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}
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pub struct Builder<'a> {
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// target state
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wasm: &'a Module,
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other: &'a Arities,
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num_result: u32,
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// translation state
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pending: Vec<Vec<Expression>>,
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stack: Vec<Expression>,
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last_stack: usize,
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}
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fn is_else_stat(inst: &Instruction) -> bool {
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inst == &Instruction::Else
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}
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fn is_dead_precursor(inst: &Instruction) -> bool {
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matches!(
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inst,
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Instruction::Unreachable | Instruction::Br(_) | Instruction::Return
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)
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}
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fn local_sum(body: &FuncBody) -> u32 {
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body.locals().iter().map(Local::count).sum()
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}
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fn load_func_at(wasm: &Module, index: usize) -> &FuncBody {
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&wasm.code_section().unwrap().bodies()[index]
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}
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impl<'a> Builder<'a> {
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pub fn new(wasm: &'a Module, other: &'a Arities) -> Builder<'a> {
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Builder {
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wasm,
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other,
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num_result: 0,
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pending: Vec::new(),
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stack: Vec::new(),
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last_stack: 0,
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}
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}
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pub fn consume(mut self, index: usize) -> Function {
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let func = load_func_at(self.wasm, index);
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let arity = &self.other.in_arity[index];
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let num_param = arity.num_param;
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let num_local = local_sum(func);
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self.num_result = arity.num_result;
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let body = self.new_forward(&mut func.code().elements());
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let num_stack = self.last_stack.try_into().unwrap();
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Function {
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num_param,
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num_local,
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num_stack,
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body,
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}
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}
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fn get_type_of(&self, index: u32) -> Arity {
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let types = self.wasm.type_section().unwrap().types();
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Arity::from_index(types, index)
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}
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fn push_recall(&mut self, num: u32) {
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let len = self.stack.len();
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for var in len..len + num as usize {
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self.stack.push(Expression::Recall(Recall { var }));
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}
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}
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fn push_block_result(&mut self, typ: BlockType) {
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let num = match typ {
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BlockType::NoResult => {
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return;
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}
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BlockType::Value(_) => 1,
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BlockType::TypeIndex(i) => self.get_type_of(i).num_result,
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};
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self.push_recall(num);
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}
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// If any expressions are still pending at the start of
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// statement, we leak them into variables.
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// Since expressions do not have set ordering rules, this is
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// safe and condenses code.
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fn gen_leak_pending(&mut self, stat: &mut Vec<Statement>) {
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self.last_stack = self.last_stack.max(self.stack.len());
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for (i, v) in self
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.stack
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.iter_mut()
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.enumerate()
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.filter(|v| !v.1.is_recalling(v.0))
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{
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let new = Expression::Recall(Recall { var: i });
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let mem = Memorize {
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var: i,
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value: std::mem::replace(v, new),
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};
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stat.push(Statement::Memorize(mem));
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}
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}
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// Pending expressions are put to sleep before entering
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// a control structure so that they are not lost.
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fn save_pending(&mut self) {
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let cloned = self.stack.iter().map(Expression::clone_recall).collect();
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self.pending.push(cloned);
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}
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fn load_pending(&mut self) {
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self.stack = self.pending.pop().unwrap();
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}
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fn gen_return(&mut self, stat: &mut Vec<Statement>) {
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let num = self.num_result as usize;
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let list = self.stack.split_off(self.stack.len() - num);
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self.gen_leak_pending(stat);
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stat.push(Statement::Return(Return { list }));
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}
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fn gen_call(&mut self, func: u32, stat: &mut Vec<Statement>) {
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let arity = self.other.arity_of(func as usize);
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let param_list = self
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.stack
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.split_off(self.stack.len() - arity.num_param as usize);
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let len = u32::try_from(self.stack.len()).unwrap();
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let result = len..len + arity.num_result;
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self.push_recall(arity.num_result);
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self.gen_leak_pending(stat);
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stat.push(Statement::Call(Call {
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func,
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result,
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param_list,
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}));
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}
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fn gen_call_indirect(&mut self, typ: u32, table: u8, stat: &mut Vec<Statement>) {
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let arity = self.get_type_of(typ);
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let index = self.stack.pop().unwrap();
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let param_list = self
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.stack
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.split_off(self.stack.len() - arity.num_param as usize);
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let len = u32::try_from(self.stack.len()).unwrap();
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let result = len..len + arity.num_result;
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self.push_recall(arity.num_result);
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self.gen_leak_pending(stat);
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stat.push(Statement::CallIndirect(CallIndirect {
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table,
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index,
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result,
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param_list,
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}));
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}
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fn push_load(&mut self, op: Load, offset: u32) {
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let pointer = Box::new(self.stack.pop().unwrap());
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self.stack.push(Expression::AnyLoad(AnyLoad {
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op,
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offset,
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pointer,
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}));
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}
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fn gen_store(&mut self, op: Store, offset: u32, stat: &mut Vec<Statement>) {
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let value = self.stack.pop().unwrap();
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let pointer = self.stack.pop().unwrap();
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self.gen_leak_pending(stat);
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stat.push(Statement::AnyStore(AnyStore {
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op,
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offset,
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pointer,
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value,
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}));
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}
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fn push_constant(&mut self, value: Value) {
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self.stack.push(Expression::Value(value));
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}
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fn push_un_op(&mut self, op: UnOp) {
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let rhs = Box::new(self.stack.pop().unwrap());
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self.stack.push(Expression::AnyUnOp(AnyUnOp { op, rhs }));
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}
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fn push_bin_op(&mut self, op: BinOp) {
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let rhs = Box::new(self.stack.pop().unwrap());
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let lhs = Box::new(self.stack.pop().unwrap());
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self.stack
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.push(Expression::AnyBinOp(AnyBinOp { op, lhs, rhs }));
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}
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fn drop_unreachable(list: &mut &[Instruction]) {
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use Instruction as Inst;
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let mut level = 1;
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loop {
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let inst = &list[0];
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*list = &list[1..];
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match inst {
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Inst::Block(_) | Inst::Loop(_) | Inst::If(_) => {
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level += 1;
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}
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Inst::Else => {
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if level == 1 {
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break;
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}
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}
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Inst::End => {
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level -= 1;
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if level == 0 {
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break;
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}
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}
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_ => {}
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}
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}
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}
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fn new_stored_body(&mut self, list: &mut &[Instruction]) -> Vec<Statement> {
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use Instruction as Inst;
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let mut stat = Vec::new();
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self.save_pending();
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loop {
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let inst = &list[0];
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*list = &list[1..];
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if let Ok(op) = UnOp::try_from(inst) {
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self.push_un_op(op);
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continue;
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} else if let Ok(op) = BinOp::try_from(inst) {
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self.push_bin_op(op);
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continue;
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}
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match inst {
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Inst::Nop => {}
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Inst::Unreachable => {
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stat.push(Statement::Unreachable);
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}
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Inst::Block(t) => {
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self.gen_leak_pending(&mut stat);
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let data = self.new_forward(list);
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self.push_block_result(*t);
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stat.push(Statement::Forward(data));
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}
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Inst::Loop(t) => {
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self.gen_leak_pending(&mut stat);
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let data = self.new_backward(list);
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self.push_block_result(*t);
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stat.push(Statement::Backward(data));
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}
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Inst::If(t) => {
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let cond = self.stack.pop().unwrap();
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self.gen_leak_pending(&mut stat);
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let data = self.new_if(cond, list);
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self.push_block_result(*t);
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stat.push(Statement::If(data));
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}
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Inst::Else => {
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self.gen_leak_pending(&mut stat);
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break;
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}
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Inst::End => {
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if list.is_empty() && self.num_result != 0 {
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self.gen_return(&mut stat);
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} else {
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self.gen_leak_pending(&mut stat);
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}
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break;
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}
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Inst::Br(i) => {
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self.gen_leak_pending(&mut stat);
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stat.push(Statement::Br(Br { target: *i }));
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}
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Inst::BrIf(i) => {
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let cond = self.stack.pop().unwrap();
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self.gen_leak_pending(&mut stat);
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stat.push(Statement::BrIf(BrIf { cond, target: *i }));
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}
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Inst::BrTable(t) => {
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let cond = self.stack.pop().unwrap();
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self.gen_leak_pending(&mut stat);
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stat.push(Statement::BrTable(BrTable {
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cond,
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data: *t.clone(),
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}));
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}
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Inst::Return => {
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self.gen_return(&mut stat);
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}
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Inst::Call(i) => {
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self.gen_call(*i, &mut stat);
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}
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Inst::CallIndirect(i, t) => {
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self.gen_call_indirect(*i, *t, &mut stat);
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}
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Inst::Drop => {
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self.stack.pop().unwrap();
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}
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Inst::Select => {
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let cond = Box::new(self.stack.pop().unwrap());
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let b = Box::new(self.stack.pop().unwrap());
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let a = Box::new(self.stack.pop().unwrap());
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self.stack.push(Expression::Select(Select { cond, a, b }));
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}
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Inst::GetLocal(i) => {
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self.stack.push(Expression::GetLocal(GetLocal { var: *i }));
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}
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Inst::SetLocal(i) => {
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let value = self.stack.pop().unwrap();
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self.gen_leak_pending(&mut stat);
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stat.push(Statement::SetLocal(SetLocal { var: *i, value }));
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}
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Inst::TeeLocal(i) => {
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self.gen_leak_pending(&mut stat);
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let value = self.stack.last().unwrap().clone_recall();
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stat.push(Statement::SetLocal(SetLocal { var: *i, value }));
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}
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Inst::GetGlobal(i) => {
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self.stack
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.push(Expression::GetGlobal(GetGlobal { var: *i }));
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}
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Inst::SetGlobal(i) => {
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let value = self.stack.pop().unwrap();
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stat.push(Statement::SetGlobal(SetGlobal { var: *i, value }));
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}
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Inst::I32Load(_, o) => self.push_load(Load::I32, *o),
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Inst::I64Load(_, o) => self.push_load(Load::I64, *o),
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Inst::F32Load(_, o) => self.push_load(Load::F32, *o),
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Inst::F64Load(_, o) => self.push_load(Load::F64, *o),
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Inst::I32Load8S(_, o) => self.push_load(Load::I32_I8, *o),
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Inst::I32Load8U(_, o) => self.push_load(Load::I32_U8, *o),
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Inst::I32Load16S(_, o) => self.push_load(Load::I32_I16, *o),
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Inst::I32Load16U(_, o) => self.push_load(Load::I32_U16, *o),
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Inst::I64Load8S(_, o) => self.push_load(Load::I64_I8, *o),
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Inst::I64Load8U(_, o) => self.push_load(Load::I64_U8, *o),
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Inst::I64Load16S(_, o) => self.push_load(Load::I64_I16, *o),
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Inst::I64Load16U(_, o) => self.push_load(Load::I64_U16, *o),
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Inst::I64Load32S(_, o) => self.push_load(Load::I64_I32, *o),
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Inst::I64Load32U(_, o) => self.push_load(Load::I64_U32, *o),
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Inst::I32Store(_, o) => self.gen_store(Store::I32, *o, &mut stat),
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Inst::I64Store(_, o) => self.gen_store(Store::I64, *o, &mut stat),
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Inst::F32Store(_, o) => self.gen_store(Store::F32, *o, &mut stat),
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Inst::F64Store(_, o) => self.gen_store(Store::F64, *o, &mut stat),
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Inst::I32Store8(_, o) => self.gen_store(Store::I32_N8, *o, &mut stat),
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Inst::I32Store16(_, o) => self.gen_store(Store::I32_N16, *o, &mut stat),
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Inst::I64Store8(_, o) => self.gen_store(Store::I64_N8, *o, &mut stat),
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Inst::I64Store16(_, o) => self.gen_store(Store::I64_N16, *o, &mut stat),
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Inst::I64Store32(_, o) => self.gen_store(Store::I64_N32, *o, &mut stat),
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Inst::CurrentMemory(i) => {
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self.stack
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.push(Expression::MemorySize(MemorySize { memory: *i }));
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}
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Inst::GrowMemory(i) => {
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let value = Box::new(self.stack.pop().unwrap());
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// `MemoryGrow` is an expression *but* it has side effects
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self.stack
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.push(Expression::MemoryGrow(MemoryGrow { memory: *i, value }));
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self.gen_leak_pending(&mut stat);
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}
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Inst::I32Const(v) => self.push_constant(Value::I32(*v)),
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Inst::I64Const(v) => self.push_constant(Value::I64(*v)),
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Inst::F32Const(v) => self.push_constant(Value::F32(f32::from_bits(*v))),
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Inst::F64Const(v) => self.push_constant(Value::F64(f64::from_bits(*v))),
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_ => unreachable!(),
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}
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if is_dead_precursor(inst) {
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Self::drop_unreachable(list);
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break;
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}
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}
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self.load_pending();
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stat
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}
|
|
|
|
fn new_else(&mut self, list: &mut &[Instruction]) -> Else {
|
|
Else {
|
|
body: self.new_stored_body(list),
|
|
}
|
|
}
|
|
|
|
fn new_if(&mut self, cond: Expression, list: &mut &[Instruction]) -> If {
|
|
let copied = <&[Instruction]>::clone(list);
|
|
let truthy = self.new_stored_body(list);
|
|
|
|
let end = copied.len() - list.len() - 1;
|
|
let falsey = is_else_stat(&copied[end]).then(|| self.new_else(list));
|
|
|
|
If {
|
|
cond,
|
|
truthy,
|
|
falsey,
|
|
}
|
|
}
|
|
|
|
fn new_backward(&mut self, list: &mut &[Instruction]) -> Backward {
|
|
Backward {
|
|
body: self.new_stored_body(list),
|
|
}
|
|
}
|
|
|
|
fn new_forward(&mut self, list: &mut &[Instruction]) -> Forward {
|
|
Forward {
|
|
body: self.new_stored_body(list),
|
|
}
|
|
}
|
|
}
|