feat: table.init

Signed-off-by: Henry Gressmann <mail@henrygressmann.de>

crates/tinywasm/src/instance.rs

@@ -144,6 +144,11 @@ impl ModuleInstance {
         *self.0.mem_addrs.get(addr as usize).expect("No mem addr for mem, this is a bug")
     }
 
+    // resolve a memory address to the global store address
+    pub(crate) fn resolve_elem_addr(&self, addr: ElemAddr) -> ElemAddr {
+        *self.0.elem_addrs.get(addr as usize).expect("No elem addr for elem, this is a bug")
+    }
+
     // resolve a global address to the global store address
     pub(crate) fn resolve_global_addr(&self, addr: GlobalAddr) -> GlobalAddr {
         self.0.global_addrs[addr as usize]

crates/tinywasm/src/runtime/executor/mod.rs

@@ -7,7 +7,7 @@ use crate::{
     CallFrame, Error, LabelArgs, ModuleInstance, Result, Store, Trap,
 };
 use alloc::{string::ToString, vec::Vec};
-use tinywasm_types::Instruction;
+use tinywasm_types::{ElementKind, Instruction};
 
 mod macros;
 mod traits;
@@ -111,7 +111,10 @@ fn exec_one(
         Nop => { /* do nothing */ }
         Unreachable => return Ok(ExecResult::Trap(crate::Trap::Unreachable)), // we don't need to include the call frame here because it's already on the stack
         Drop => stack.values.pop().map(|_| ())?,
-        Select(t) => {
+
+        Select(
+            _valtype, // due to validation, we know that the type of the values on the stack are correct
+        ) => {
             // due to validation, we know that the type of the values on the stack
             let cond: i32 = stack.values.pop()?.into();
             let val2 = stack.values.pop()?;
@@ -554,6 +557,7 @@ fn exec_one(
         I64TruncF32U => checked_conv_float!(f32, u64, i64, stack),
         I64TruncF64U => checked_conv_float!(f64, u64, i64, stack),
 
+        // TODO: uninitialized element traps
         TableGet(table_index) => {
             let table_idx = module.resolve_table_addr(*table_index);
             let table = store.get_table(table_idx as usize)?;
@@ -575,6 +579,24 @@ fn exec_one(
             stack.values.push(table.borrow().size().into());
         }
 
+        TableInit(table_index, elem_index) => {
+            let table_idx = module.resolve_table_addr(*table_index);
+            let table = store.get_table(table_idx as usize)?;
+
+            let elem_idx = module.resolve_elem_addr(*elem_index);
+            let elem = store.get_elem(elem_idx as usize)?;
+
+            if elem.kind != ElementKind::Passive {
+                return Err(Trap::TableOutOfBounds { offset: 0, len: 0, max: 0 }.into());
+            }
+
+            let Some(items) = elem.items.as_ref() else {
+                return Err(Trap::TableOutOfBounds { offset: 0, len: 0, max: 0 }.into());
+            };
+
+            table.borrow_mut().init(0, items)?;
+        }
+
         I32TruncSatF32S => arithmetic_single!(trunc, f32, i32, stack),
         I32TruncSatF32U => arithmetic_single!(trunc, f32, u32, stack),
         I32TruncSatF64S => arithmetic_single!(trunc, f64, i32, stack),

crates/tinywasm/src/runtime/stack/value_stack.rs

@@ -106,16 +106,6 @@ impl ValueStack {
         Ok(&self.stack[self.top - n..self.top])
     }
 
-    #[inline]
-    pub(crate) fn pop_n(&mut self, n: usize) -> Result<Vec<RawWasmValue>> {
-        if self.top < n {
-            return Err(Error::StackUnderflow);
-        }
-        self.top -= n;
-        let res = self.stack.drain(self.top..).rev().collect::<Vec<_>>();
-        Ok(res)
-    }
-
     #[inline]
     pub(crate) fn pop_n_rev(&mut self, n: usize) -> Result<Vec<RawWasmValue>> {
         if self.top < n {

crates/tinywasm/src/store.rs

@@ -342,6 +342,11 @@ impl Store {
         self.data.tables.get(addr).ok_or_else(|| Error::Other(format!("table {} not found", addr)))
     }
 
+    /// Get the element at the actual index in the store
+    pub(crate) fn get_elem(&self, addr: usize) -> Result<&ElemInstance> {
+        self.data.elems.get(addr).ok_or_else(|| Error::Other(format!("element {} not found", addr)))
+    }
+
     /// Get the global at the actual index in the store
     pub(crate) fn get_global_val(&self, addr: usize) -> Result<RawWasmValue> {
         self.data
@@ -548,14 +553,14 @@ impl GlobalInstance {
 /// See <https://webassembly.github.io/spec/core/exec/runtime.html#element-instances>
 #[derive(Debug)]
 pub(crate) struct ElemInstance {
-    _kind: ElementKind,
-    _items: Option<Vec<u32>>,   // none is the element was dropped
-    _owner: ModuleInstanceAddr, // index into store.module_instances
+    pub(crate) kind: ElementKind,
+    pub(crate) items: Option<Vec<u32>>, // none is the element was dropped
+    _owner: ModuleInstanceAddr,         // index into store.module_instances
 }
 
 impl ElemInstance {
     pub(crate) fn new(kind: ElementKind, owner: ModuleInstanceAddr, items: Option<Vec<u32>>) -> Self {
-        Self { _kind: kind, _owner: owner, _items: items }
+        Self { kind, _owner: owner, items }
     }
 }
 

crates/types/src/lib.rs

@@ -465,7 +465,7 @@ pub struct Element {
     pub ty: ValType,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub enum ElementKind {
     Passive,
     Active { table: TableAddr, offset: ConstInstruction },