From 4765aecf7806bfa0020845a476662d64a3cd1d08 Mon Sep 17 00:00:00 2001
From: Sergey Pepyakin <s.pepyakin@gmail.com>
Date: Mon, 29 Jan 2018 17:23:44 +0300
Subject: [PATCH] call_indirect traps.

---
 src/lib.rs    |  3 +++
 src/runner.rs | 12 ++++--------
 src/table.rs  |  7 ++-----
 3 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index b14a184..20ae2f4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -110,6 +110,9 @@ use std::collections::HashMap;
 pub enum Trap {
 	Unreachable,
 	MemoryAccessOutOfBounds,
+	TableAccessOutOfBounds,
+	ElemUninitialized,
+	ElemSignatureMismatch,
 }
 
 /// Internal interpreter error.
diff --git a/src/runner.rs b/src/runner.rs
index 21ced8a..fc88e1a 100644
--- a/src/runner.rs
+++ b/src/runner.rs
@@ -438,7 +438,9 @@ impl<'a, E: Externals> Interpreter<'a, E> {
 			.module()
 			.table_by_index(DEFAULT_TABLE_INDEX)
 			.expect("Due to validation table should exists");
-		let func_ref = table.get(table_func_idx)?;
+		let func_ref = table.get(table_func_idx)
+			.map_err(|_| Error::Trap(Trap::TableAccessOutOfBounds))?
+			.ok_or_else(|| Error::Trap(Trap::ElemUninitialized))?;
 
 		{
 			let actual_function_type = func_ref.signature();
@@ -448,13 +450,7 @@ impl<'a, E: Externals> Interpreter<'a, E> {
 				.expect("Due to validation type should exists");
 
 			if &*required_function_type != actual_function_type {
-				return Err(Error::Function(format!(
-					"expected function with signature ({:?}) -> {:?} when got with ({:?}) -> {:?}",
-					required_function_type.params(),
-					required_function_type.return_type(),
-					actual_function_type.params(),
-					actual_function_type.return_type()
-				)));
+				return Err(Error::Trap(Trap::ElemSignatureMismatch));
 			}
 		}
 
diff --git a/src/table.rs b/src/table.rs
index eac4b0b..4c47da3 100644
--- a/src/table.rs
+++ b/src/table.rs
@@ -107,7 +107,7 @@ impl TableInstance {
 	}
 
 	/// Get the specific value in the table
-	pub fn get(&self, offset: u32) -> Result<FuncRef, Error> {
+	pub fn get(&self, offset: u32) -> Result<Option<FuncRef>, Error> {
 		let buffer = self.buffer.borrow();
 		let buffer_len = buffer.len();
 		let table_elem = buffer.get(offset as usize).cloned().ok_or_else(||
@@ -117,10 +117,7 @@ impl TableInstance {
 				buffer_len
 			)),
 		)?;
-		Ok(table_elem.ok_or_else(|| Error::Table(format!(
-			"trying to read uninitialized element on index {}",
-			offset
-		)))?)
+		Ok(table_elem)
 	}
 
 	/// Set the table element to the specified function.