Extend exception handling support

Still some tests failing, but added catch & throw instructions as well as exception reference support.

src/instructions/exceptions.rs

@@ -0,0 +1,49 @@
+use super::Instruction;
+use crate::builtins::WasmbinCountable;
+use crate::indices::{ExceptionId, LabelId};
+use crate::io::{encode_decode_as, Wasmbin};
+use crate::types::BlockType;
+use crate::visit::Visit;
+
+#[derive(Wasmbin)]
+#[repr(u8)]
+enum CatchRepr {
+    Catch {
+        exception: ExceptionId,
+        target: LabelId,
+    } = 0x00,
+    CatchRef {
+        exception: ExceptionId,
+        target: LabelId,
+    } = 0x01,
+    CatchAll {
+        target: LabelId,
+    } = 0x02,
+    CatchAllRef {
+        target: LabelId,
+    } = 0x03,
+}
+
+#[derive(WasmbinCountable, Debug, PartialEq, Eq, Hash, Clone, Visit)]
+pub struct Catch {
+    /// Whether to store an exception reference on the stack.
+    pub catch_ref: bool,
+    /// Catch a specific exception or any exception if set to `None`.
+    pub exception_filter: Option<ExceptionId>,
+    /// Target label.
+    pub target: LabelId,
+}
+
+encode_decode_as!(Catch, {
+    (Catch { catch_ref: false, exception_filter: Some(exception), target }) <=> (CatchRepr::Catch { exception, target }),
+    (Catch { catch_ref: true, exception_filter: Some(exception), target }) <=> (CatchRepr::CatchRef { exception, target }),
+    (Catch { catch_ref: false, exception_filter: None, target }) <=> (CatchRepr::CatchAll { target }),
+    (Catch { catch_ref: true, exception_filter: None, target }) <=> (CatchRepr::CatchAllRef { target }),
+});
+
+#[derive(Wasmbin, Debug, PartialEq, Eq, Hash, Clone, Visit)]
+pub struct TryTable {
+    pub block_type: BlockType,
+    pub catches: Vec<Catch>,
+    pub instructions: Vec<Instruction>,
+}

src/instructions/mod.rs

@@ -145,6 +145,10 @@ pub enum Instruction {
     LoopStart(BlockType) = OP_CODE_LOOP_START,
     IfStart(BlockType) = OP_CODE_IF_START,
     IfElse = 0x05,
+    #[cfg(feature = "exception-handling")]
+    Throw(crate::indices::ExceptionId) = 0x08,
+    #[cfg(feature = "exception-handling")]
+    ThrowRef = 0x0A,
     End = OP_CODE_END,
     Br(LabelId) = 0x0C,
     BrIf(LabelId) = 0x0D,
@@ -162,6 +166,8 @@ pub enum Instruction {
     Drop = 0x1A,
     Select = 0x1B,
     SelectWithTypes(Vec<ValueType>) = 0x1C,
+    #[cfg(feature = "exception-handling")]
+    TryTable(TryTable) = 0x1F,
     LocalGet(LocalId) = 0x20,
     LocalSet(LocalId) = 0x21,
     LocalTee(LocalId) = 0x22,
@@ -345,3 +351,8 @@ pub use simd::SIMD;
 pub mod threads;
 #[cfg(feature = "threads")]
 pub use threads::Atomic;
+
+#[cfg(feature = "exception-handling")]
+pub mod exceptions;
+#[cfg(feature = "exception-handling")]
+pub use exceptions::{Catch, TryTable};

src/types.rs

@@ -182,6 +182,8 @@ encode_decode_as!(MemType, {
 pub enum RefType {
     Func = 0x70,
     Extern = 0x6F,
+    #[cfg(feature = "exception-handling")]
+    Exception = 0x69,
 }
 
 /// [Table type](https://webassembly.github.io/spec/core/binary/types.html#table-types).