Merge remote-tracking branch 'origin/flat-stack' into fuzz

.travis.yml

@@ -3,6 +3,9 @@ sudo: required
 language:
 - rust
 - cpp
+rust:
+  - nightly
+  - stable
 addons:
   apt:
     sources:
@@ -12,18 +15,16 @@ addons:
     - g++-6
     - cmake
 env:
-- NIGHTLY_TOOLCHAIN=nightly-2018-02-05
+- CC=/usr/bin/gcc-6 CXX=/usr/bin/g++-6
 
 install:
 # Install `cargo-deadlinks` unless it is currently installed.
 - command -v cargo-deadlinks &> /dev/null || cargo install cargo-deadlinks
-# Install nightly toolchain.
-- rustup toolchain install $NIGHTLY_TOOLCHAIN
+- if [ "$TRAVIS_RUST_VERSION" == "nightly" ]; then rustup target add wasm32-unknown-unknown; fi
 script:
-- export CC=/usr/bin/gcc-6
-- export CXX=/usr/bin/g++-6
-# Make sure fuzz targets are not broken.
-- rustup run $NIGHTLY_TOOLCHAIN cargo check --tests --manifest-path=fuzz/Cargo.toml
+# Make sure nightly targets are not broken.
+- if [ "$TRAVIS_RUST_VERSION" == "nightly" ]; then cargo check --tests --manifest-path=fuzz/Cargo.toml; fi
+- if [ "$TRAVIS_RUST_VERSION" == "nightly" ]; then cargo check --benches --manifest-path=benches/Cargo.toml; fi
 - ./test.sh
 - ./doc.sh
 after_success: |

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "wasmi"
-version = "0.1.2"
+version = "0.2.0"
 authors = ["Nikolay Volf <nikvolf@gmail.com>", "Svyatoslav Nikolsky <svyatonik@yandex.ru>", "Sergey Pepyakin <s.pepyakin@gmail.com>"]
 license = "MIT/Apache-2.0"
 readme = "README.md"
@@ -8,19 +8,15 @@ repository = "https://github.com/paritytech/wasmi"
 documentation = "https://paritytech.github.io/wasmi/"
 description = "WebAssembly interpreter"
 keywords = ["wasm", "webassembly", "bytecode", "interpreter"]
-exclude = [ "/res/*", "/tests/*", "/fuzz/*" ]
+exclude = [ "/res/*", "/tests/*", "/fuzz/*", "/benches/*" ]
 
 [dependencies]
 # parity-wasm = "0.27"
 parity-wasm = { git = "https://github.com/paritytech/parity-wasm.git", rev = "0a61083238d8d9d8d9f6451a5d0da17674b11c21" }
 byteorder = "1.0"
 memory_units = "0.3.0"
+nan-preserving-float = "0.1.0"
 
 [dev-dependencies]
-wabt = "~0.2.2"
-
-[features]
-# 32-bit platforms are not supported and not tested. Use this flag if you really want to use
-# wasmi on these platforms.
-# See https://github.com/pepyakin/wasmi/issues/43
-opt-in-32bit = []
+assert_matches = "1.1"
+wabt = "0.3"

benches/.gitignore

@@ -0,0 +1,3 @@
+/target
+*.trace
+

benches/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "benches"
+version = "0.1.0"
+authors = ["Sergey Pepyakin <s.pepyakin@gmail.com>"]
+
+[dependencies]
+wasmi = { path = ".." }
+assert_matches = "1.2"
+
+[profile.bench]
+debug = true

benches/build.rs

@@ -0,0 +1,32 @@
+use std::env;
+use std::process;
+
+
+fn main() {
+	println!("cargo:rerun-if-changed=./wasm-kernel/");
+
+	// The CARGO environment variable provides a path to the executable that
+	// runs this build process.
+	let cargo_bin = env::var("CARGO").expect("CARGO env variable should be defined");
+
+	// Build a release version of wasm-kernel. The code in the output wasm binary
+	// will be used in benchmarks.
+	let output = process::Command::new(cargo_bin)
+		.arg("build")
+		.arg("--target=wasm32-unknown-unknown")
+		.arg("--release")
+		.arg("--manifest-path=./wasm-kernel/Cargo.toml")
+		.arg("--verbose")
+		.output()
+		.expect("failed to execute `cargo`");
+
+	if !output.status.success() {
+		let msg = format!(
+			"status: {status}\nstdout: {stdout}\nstderr: {stderr}\n",
+			status=output.status,
+			stdout=String::from_utf8_lossy(&output.stdout),
+			stderr=String::from_utf8_lossy(&output.stderr),
+		);
+		panic!("{}", msg);
+	}
+}

benches/src/lib.rs

@@ -0,0 +1,43 @@
+#![feature(test)]
+
+extern crate test;
+extern crate wasmi;
+#[macro_use]
+extern crate assert_matches;
+
+use std::error;
+use std::fs::File;
+use wasmi::{ImportsBuilder, Module, ModuleInstance, NopExternals, RuntimeValue};
+
+use test::Bencher;
+
+// Load a module from a file.
+fn load_from_file(filename: &str) -> Result<Module, Box<error::Error>> {
+	use std::io::prelude::*;
+	let mut file = File::open(filename)?;
+	let mut buf = Vec::new();
+	file.read_to_end(&mut buf)?;
+	Ok(Module::from_buffer(buf)?)
+}
+
+#[bench]
+fn bench_tiny_keccak(b: &mut Bencher) {
+	let wasm_kernel = load_from_file(
+		"./wasm-kernel/target/wasm32-unknown-unknown/release/wasm_kernel.wasm",
+	).expect("failed to load wasm_kernel. Is `build.rs` broken?");
+
+	let instance = ModuleInstance::new(&wasm_kernel, &ImportsBuilder::default())
+		.expect("failed to instantiate wasm module")
+		.assert_no_start();
+
+	let test_data_ptr = assert_matches!(
+		instance.invoke_export("prepare_tiny_keccak", &[], &mut NopExternals),
+		Ok(Some(v @ RuntimeValue::I32(_))) => v
+	);
+
+	b.iter(|| {
+		instance
+			.invoke_export("bench_tiny_keccak", &[test_data_ptr], &mut NopExternals)
+			.unwrap();
+	});
+}

benches/wasm-kernel/.gitignore

@@ -0,0 +1 @@
+/target

benches/wasm-kernel/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "wasm-kernel"
+version = "0.1.0"
+authors = ["Sergey Pepyakin <s.pepyakin@gmail.com>"]
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+tiny-keccak = "1.4.2"
+rlibc = "1.0"
+
+[profile.release]
+panic = "abort"
+lto = true
+opt-level = "z"

benches/wasm-kernel/src/lib.rs

@@ -0,0 +1,50 @@
+#![no_std]
+#![feature(lang_items)]
+#![feature(core_intrinsics)]
+#![feature(panic_implementation)]
+
+extern crate rlibc;
+extern crate tiny_keccak;
+
+use tiny_keccak::Keccak;
+
+#[no_mangle]
+#[panic_implementation]
+pub fn panic_fmt(_info: &::core::panic::PanicInfo) -> ! {
+	use core::intrinsics;
+	unsafe {
+		intrinsics::abort();
+	}
+}
+
+pub struct TinyKeccakTestData {
+	data: &'static [u8],
+	result: &'static mut [u8],
+}
+
+#[no_mangle]
+pub extern "C" fn prepare_tiny_keccak() -> *const TinyKeccakTestData {
+	static DATA: [u8; 4096] = [254u8; 4096];
+	static mut RESULT: [u8; 32] = [0u8; 32];
+
+	static mut TEST_DATA: Option<TinyKeccakTestData> = None;
+
+	unsafe {
+		if let None = TEST_DATA {
+			TEST_DATA = Some(TinyKeccakTestData {
+				data: &DATA,
+				result: &mut RESULT,
+			});
+		}
+		TEST_DATA.as_ref().unwrap() as *const TinyKeccakTestData
+	}
+}
+
+#[no_mangle]
+pub extern "C" fn bench_tiny_keccak(test_data: *const TinyKeccakTestData) {
+	unsafe {
+		let mut keccak = Keccak::new_keccak256();
+		keccak.update((*test_data).data);
+		keccak.finalize((*test_data).result);
+	}
+}

doc.sh

@@ -4,11 +4,7 @@ set -eux
 
 cd $(dirname $0)
 
-if [ -s NIGHTLY_TOOLCHAIN ]; then
-	rustup run $NIGHTLY_TOOLCHAIN cargo doc
-else
-	cargo doc
-fi;
+cargo doc
 
 # cargo-deadlinks will check any links in docs generated by `cargo doc`.
 # This is useful as rustdoc uses raw links which are error prone.

examples/invoke.rs

@@ -64,8 +64,8 @@ fn main() {
         function_type.params().iter().enumerate().map(|(i, value)| match value {
             &ValueType::I32 => RuntimeValue::I32(program_args[i].parse::<i32>().expect(&format!("Can't parse arg #{} as i32", program_args[i]))),
             &ValueType::I64 => RuntimeValue::I64(program_args[i].parse::<i64>().expect(&format!("Can't parse arg #{} as i64", program_args[i]))),
-            &ValueType::F32 => RuntimeValue::F32(program_args[i].parse::<f32>().expect(&format!("Can't parse arg #{} as f32", program_args[i]))),
-            &ValueType::F64 => RuntimeValue::F64(program_args[i].parse::<f64>().expect(&format!("Can't parse arg #{} as f64", program_args[i]))),
+            &ValueType::F32 => RuntimeValue::F32(program_args[i].parse::<f32>().expect(&format!("Can't parse arg #{} as f32", program_args[i])).into()),
+            &ValueType::F64 => RuntimeValue::F64(program_args[i].parse::<f64>().expect(&format!("Can't parse arg #{} as f64", program_args[i])).into()),
         }).collect::<Vec<RuntimeValue>>()
     };
 

src/common/mod.rs

@@ -1,4 +1,3 @@
-use parity_wasm::elements::BlockType;
 
 pub mod stack;
 
@@ -7,38 +6,4 @@ pub const DEFAULT_MEMORY_INDEX: u32 = 0;
 /// Index of default table.
 pub const DEFAULT_TABLE_INDEX: u32 = 0;
 
-/// Control stack frame.
-#[derive(Debug, Clone)]
-pub struct BlockFrame {
-	/// Frame type.
-	pub frame_type: BlockFrameType,
-	/// A signature, which is a block signature type indicating the number and types of result values of the region.
-	pub block_type: BlockType,
-	/// A label for reference to block instruction.
-	pub begin_position: usize,
-	/// A label for reference from branch instructions.
-	pub branch_position: usize,
-	/// A label for reference from end instructions.
-	pub end_position: usize,
-	/// A limit integer value, which is an index into the value stack indicating where to reset it to on a branch to that label.
-	pub value_stack_len: usize,
-	/// Boolean which signals whether value stack became polymorphic. Value stack starts in non-polymorphic state and
-	/// becomes polymorphic only after an instruction that never passes control further is executed,
-	/// i.e. `unreachable`, `br` (but not `br_if`!), etc.
-	pub polymorphic_stack: bool,
-}
-
-/// Type of block frame.
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum BlockFrameType {
-	/// Function frame.
-	Function,
-	/// Usual block frame.
-	Block,
-	/// Loop frame (branching to the beginning of block).
-	Loop,
-	/// True-subblock of if expression.
-	IfTrue,
-	/// False-subblock of if expression.
-	IfFalse,
-}
+// TODO: Move BlockFrame under validation.

src/common/stack.rs

@@ -1,5 +1,4 @@
 
-use std::collections::VecDeque;
 use std::error;
 use std::fmt;
 
@@ -22,7 +21,7 @@ impl error::Error for Error {
 #[derive(Debug)]
 pub struct StackWithLimit<T> where T: Clone {
 	/// Stack values.
-	values: VecDeque<T>,
+	values: Vec<T>,
 	/// Stack limit (maximal stack len).
 	limit: usize,
 }
@@ -30,7 +29,7 @@ pub struct StackWithLimit<T> where T: Clone {
 impl<T> StackWithLimit<T> where T: Clone {
 	pub fn with_limit(limit: usize) -> Self {
 		StackWithLimit {
-			values: VecDeque::new(),
+			values: Vec::new(),
 			limit: limit
 		}
 	}
@@ -43,19 +42,17 @@ impl<T> StackWithLimit<T> where T: Clone {
 		self.values.len()
 	}
 
-	pub fn limit(&self) -> usize {
-		self.limit
-	}
-
 	pub fn top(&self) -> Result<&T, Error> {
+		let len = self.values.len();
 		self.values
-			.back()
+			.get(len - 1)
 			.ok_or_else(|| Error("non-empty stack expected".into()))
 	}
 
 	pub fn top_mut(&mut self) -> Result<&mut T, Error> {
+		let len = self.values.len();
 		self.values
-			.back_mut()
+			.get_mut(len - 1)
 			.ok_or_else(|| Error("non-empty stack expected".into()))
 	}
 
@@ -72,13 +69,13 @@ impl<T> StackWithLimit<T> where T: Clone {
 			return Err(Error(format!("exceeded stack limit {}", self.limit)));
 		}
 
-		self.values.push_back(value);
+		self.values.push(value);
 		Ok(())
 	}
 
 	pub fn pop(&mut self) -> Result<T, Error> {
 		self.values
-			.pop_back()
+			.pop()
 			.ok_or_else(|| Error("non-empty stack expected".into()))
 	}
 

src/func.rs

@@ -1,12 +1,12 @@
 use std::rc::{Rc, Weak};
 use std::fmt;
-use std::collections::HashMap;
-use parity_wasm::elements::{Local, Opcodes};
+use parity_wasm::elements::Local;
 use {Trap, TrapKind, Signature};
 use host::Externals;
 use runner::{check_function_args, Interpreter};
 use value::RuntimeValue;
 use module::ModuleInstance;
+use isa;
 
 /// Reference to a function (See [`FuncInstance`] for details).
 ///
@@ -158,6 +158,5 @@ impl FuncInstance {
 #[derive(Clone, Debug)]
 pub struct FuncBody {
 	pub locals: Vec<Local>,
-	pub opcodes: Opcodes,
-	pub labels: HashMap<usize, usize>,
+	pub code: isa::Instructions,
 }

src/isa.rs

@@ -0,0 +1,255 @@
+//! An instruction set used by wasmi.
+//!
+//! The instruction set is mostly derived from Wasm. However,
+//! there is a substantial difference.
+//!
+//! # Structured Stack Machine vs Traditional One
+//!
+//! Wasm is a structured stack machine. Wasm encodes control flow in structures
+//! similar to that commonly found in a programming languages
+//! such as if, while. That contrasts to a traditional stack machine which
+//!  encodes all control flow with goto-like instructions.
+//!
+//! Structured stack machine code aligns well with goals of Wasm,
+//! namely providing fast validation of Wasm code and compilation to native code.
+//!
+//! Unfortunately, the downside of structured stack machine code is
+//! that it is less convenient to interpret. For example, let's look at
+//! the following example in hypothetical structured stack machine:
+//!
+//! ```plain
+//! loop
+//!   ...
+//!   if_true_jump_to_end
+//!   ...
+//! end
+//! ```
+//!
+//! To execute `if_true_jump_to_end` , the interpreter needs to skip all instructions
+//! until it reaches the *matching* `end`. That's quite inefficient compared
+//! to a plain goto to the specific position.
+//!
+//! # Differences from Wasm
+//!
+//! - There is no `nop` instruction.
+//! - All control flow strucutres are flattened to plain gotos.
+//! - Implicit returns via reaching function scope `End` are replaced with an explicit `return` instruction.
+//! - Locals live on the value stack now.
+//! - Load/store instructions doesn't take `align` parameter.
+//! - *.const store value in straight encoding.
+//! - Reserved immediates are ignored for `call_indirect`, `current_memory`, `grow_memory`.
+//!
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Target {
+	pub dst_pc: u32,
+	pub drop: u32,
+	pub keep: u8,
+}
+
+#[allow(unused)] // TODO: Remove
+#[derive(Debug, Clone, PartialEq)]
+pub enum Instruction {
+	/// Push a local variable or an argument from the specified depth.
+	GetLocal(u32),
+
+	/// Pop a value and put it in at the specified depth.
+	SetLocal(u32),
+
+	/// Copy a value to the specified depth.
+	TeeLocal(u32),
+
+	/// Similar to the Wasm ones, but instead of a label depth
+	/// they specify direct PC.
+	Br(Target),
+	BrIfEqz(Target),
+	BrIfNez(Target),
+
+	/// Last one is the default.
+	///
+	/// Can be less than zero.
+	BrTable(Box<[Target]>),
+
+	Unreachable,
+	Return {
+		drop: u32,
+		keep: u8,
+	},
+
+	Call(u32),
+	CallIndirect(u32),
+
+	Drop,
+	Select,
+
+	GetGlobal(u32),
+	SetGlobal(u32),
+
+	I32Load(u32),
+	I64Load(u32),
+	F32Load(u32),
+	F64Load(u32),
+	I32Load8S(u32),
+	I32Load8U(u32),
+	I32Load16S(u32),
+	I32Load16U(u32),
+	I64Load8S(u32),
+	I64Load8U(u32),
+	I64Load16S(u32),
+	I64Load16U(u32),
+	I64Load32S(u32),
+	I64Load32U(u32),
+	I32Store(u32),
+	I64Store(u32),
+	F32Store(u32),
+	F64Store(u32),
+	I32Store8(u32),
+	I32Store16(u32),
+	I64Store8(u32),
+	I64Store16(u32),
+	I64Store32(u32),
+
+	CurrentMemory,
+	GrowMemory,
+
+	I32Const(i32),
+	I64Const(i64),
+	F32Const(u32),
+	F64Const(u64),
+
+	I32Eqz,
+	I32Eq,
+	I32Ne,
+	I32LtS,
+	I32LtU,
+	I32GtS,
+	I32GtU,
+	I32LeS,
+	I32LeU,
+	I32GeS,
+	I32GeU,
+
+	I64Eqz,
+	I64Eq,
+	I64Ne,
+	I64LtS,
+	I64LtU,
+	I64GtS,
+	I64GtU,
+	I64LeS,
+	I64LeU,
+	I64GeS,
+	I64GeU,
+
+	F32Eq,
+	F32Ne,
+	F32Lt,
+	F32Gt,
+	F32Le,
+	F32Ge,
+
+	F64Eq,
+	F64Ne,
+	F64Lt,
+	F64Gt,
+	F64Le,
+	F64Ge,
+
+	I32Clz,
+	I32Ctz,
+	I32Popcnt,
+	I32Add,
+	I32Sub,
+	I32Mul,
+	I32DivS,
+	I32DivU,
+	I32RemS,
+	I32RemU,
+	I32And,
+	I32Or,
+	I32Xor,
+	I32Shl,
+	I32ShrS,
+	I32ShrU,
+	I32Rotl,
+	I32Rotr,
+
+	I64Clz,
+	I64Ctz,
+	I64Popcnt,
+	I64Add,
+	I64Sub,
+	I64Mul,
+	I64DivS,
+	I64DivU,
+	I64RemS,
+	I64RemU,
+	I64And,
+	I64Or,
+	I64Xor,
+	I64Shl,
+	I64ShrS,
+	I64ShrU,
+	I64Rotl,
+	I64Rotr,
+	F32Abs,
+	F32Neg,
+	F32Ceil,
+	F32Floor,
+	F32Trunc,
+	F32Nearest,
+	F32Sqrt,
+	F32Add,
+	F32Sub,
+	F32Mul,
+	F32Div,
+	F32Min,
+	F32Max,
+	F32Copysign,
+	F64Abs,
+	F64Neg,
+	F64Ceil,
+	F64Floor,
+	F64Trunc,
+	F64Nearest,
+	F64Sqrt,
+	F64Add,
+	F64Sub,
+	F64Mul,
+	F64Div,
+	F64Min,
+	F64Max,
+	F64Copysign,
+
+	I32WrapI64,
+	I32TruncSF32,
+	I32TruncUF32,
+	I32TruncSF64,
+	I32TruncUF64,
+	I64ExtendSI32,
+	I64ExtendUI32,
+	I64TruncSF32,
+	I64TruncUF32,
+	I64TruncSF64,
+	I64TruncUF64,
+	F32ConvertSI32,
+	F32ConvertUI32,
+	F32ConvertSI64,
+	F32ConvertUI64,
+	F32DemoteF64,
+	F64ConvertSI32,
+	F64ConvertUI32,
+	F64ConvertSI64,
+	F64ConvertUI64,
+	F64PromoteF32,
+
+	I32ReinterpretF32,
+	I64ReinterpretF64,
+	F32ReinterpretI32,
+	F64ReinterpretI64,
+}
+
+#[derive(Debug, Clone)]
+pub struct Instructions {
+	pub code: Vec<Instruction>,
+}

src/lib.rs

@@ -98,20 +98,17 @@
 
 #[cfg(test)]
 extern crate wabt;
+#[cfg(test)]
+#[macro_use]
+extern crate assert_matches;
+
 extern crate parity_wasm;
 extern crate byteorder;
 extern crate memory_units as memory_units_crate;
-
-#[cfg(all(not(feature = "opt-in-32bit"), target_pointer_width = "32"))]
-compile_error! {
-"32-bit targets are not supported at the moment.
-You can use 'opt-in-32bit' feature.
-See https://github.com/pepyakin/wasmi/issues/43"
-}
+extern crate nan_preserving_float;
 
 use std::fmt;
 use std::error;
-use std::collections::HashMap;
 
 /// Error type which can thrown by wasm code or by host environment.
 ///
@@ -358,6 +355,7 @@ mod imports;
 mod global;
 mod func;
 mod types;
+mod isa;
 
 #[cfg(test)]
 mod tests;
@@ -380,12 +378,11 @@ pub mod memory_units {
 
 /// Deserialized module prepared for instantiation.
 pub struct Module {
-	labels: HashMap<usize, HashMap<usize, usize>>,
+	code_map: Vec<isa::Instructions>,
 	module: parity_wasm::elements::Module,
 }
 
 impl Module {
-
 	/// Create `Module` from `parity_wasm::elements::Module`.
 	///
 	/// This function will load, validate and prepare a `parity_wasm`'s `Module`.
@@ -421,16 +418,76 @@ impl Module {
 	pub fn from_parity_wasm_module(module: parity_wasm::elements::Module) -> Result<Module, Error> {
 		use validation::{validate_module, ValidatedModule};
 		let ValidatedModule {
-			labels,
+			code_map,
 			module,
 		} = validate_module(module)?;
 
 		Ok(Module {
-			labels,
+			code_map,
 			module,
 		})
 	}
 
+	/// Fail if the module contains any floating-point operations
+	///
+	/// # Errors
+	///
+	/// Returns `Err` if provided `Module` is not valid.
+	///
+	/// # Examples
+	///
+	/// ```rust
+	/// # extern crate wasmi;
+	/// # extern crate wabt;
+	///
+	/// let wasm_binary: Vec<u8> =
+	///     wabt::wat2wasm(
+	///         r#"
+	///         (module
+	///          (func $add (param $lhs i32) (param $rhs i32) (result i32)
+	///                get_local $lhs
+	///                get_local $rhs
+	///                i32.add))
+	///         "#,
+	///     )
+	///     .expect("failed to parse wat");
+	///
+	/// // Load wasm binary and prepare it for instantiation.
+	/// let module = wasmi::Module::from_buffer(&wasm_binary).expect("Parsing failed");
+	/// assert!(module.deny_floating_point().is_ok());
+	///
+	/// let wasm_binary: Vec<u8> =
+	///     wabt::wat2wasm(
+	///         r#"
+	///         (module
+	///          (func $add (param $lhs f32) (param $rhs f32) (result f32)
+	///                get_local $lhs
+	///                get_local $rhs
+	///                f32.add))
+	///         "#,
+	///     )
+	///     .expect("failed to parse wat");
+	///
+	/// let module = wasmi::Module::from_buffer(&wasm_binary).expect("Parsing failed");
+	/// assert!(module.deny_floating_point().is_err());
+	///
+	/// let wasm_binary: Vec<u8> =
+	///     wabt::wat2wasm(
+	///         r#"
+	///         (module
+	///          (func $add (param $lhs f32) (param $rhs f32) (result f32)
+	///                get_local $lhs))
+	///         "#,
+	///     )
+	///     .expect("failed to parse wat");
+	///
+	/// let module = wasmi::Module::from_buffer(&wasm_binary).expect("Parsing failed");
+	/// assert!(module.deny_floating_point().is_err());
+	/// ```
+	pub fn deny_floating_point(&self) -> Result<(), Error> {
+		validation::deny_floating_point(&self.module).map_err(Into::into)
+	}
+
 	/// Create `Module` from a given buffer.
 	///
 	/// This function will deserialize wasm module from a given module,
@@ -467,7 +524,7 @@ impl Module {
 		&self.module
 	}
 
-	pub(crate) fn labels(&self) -> &HashMap<usize, HashMap<usize, usize>> {
-		&self.labels
+	pub(crate) fn code(&self) -> &Vec<isa::Instructions> {
+		&self.code_map
 	}
 }

src/memory.rs

@@ -48,7 +48,7 @@ impl ::std::ops::Deref for MemoryRef {
 ///
 /// [`LINEAR_MEMORY_PAGE_SIZE`]: constant.LINEAR_MEMORY_PAGE_SIZE.html
 pub struct MemoryInstance {
-	/// Memofy limits.
+	/// Memory limits.
 	limits: ResizableLimits,
 	/// Linear memory buffer.
 	buffer: RefCell<Vec<u8>>,
@@ -315,7 +315,7 @@ impl MemoryInstance {
 		Ok(())
 	}
 
-	/// Fill memory region with a specified value.
+	/// Fill the memory region with the specified value.
 	///
 	/// Semantically equivalent to `memset`.
 	///
@@ -330,7 +330,7 @@ impl MemoryInstance {
 		Ok(())
 	}
 
-	/// Fill specified memory region with zeroes.
+	/// Fill the specified memory region with zeroes.
 	///
 	/// # Errors
 	///
@@ -338,6 +338,35 @@ impl MemoryInstance {
 	pub fn zero(&self, offset: usize, len: usize) -> Result<(), Error> {
 		self.clear(offset, 0, len)
 	}
+
+	/// Provides direct access to the underlying memory buffer.
+	///
+	/// # Panics
+	///
+	/// Any call that requires write access to memory (such as [`set`], [`clear`], etc) made within
+	/// the closure will panic. Proceed with caution.
+	///
+	/// [`set`]: #method.get
+	/// [`clear`]: #method.set
+	pub fn with_direct_access<R, F: FnOnce(&[u8]) -> R>(&self, f: F) -> R {
+		let buf = self.buffer.borrow();
+		f(&*buf)
+	}
+
+	/// Provides direct mutable access to the underlying memory buffer.
+	///
+	/// # Panics
+	///
+	/// Any calls that requires either read or write access to memory (such as [`get`], [`set`], [`copy`], etc) made
+	/// within the closure will panic. Proceed with caution.
+	///
+	/// [`get`]: #method.get
+	/// [`set`]: #method.set
+	/// [`copy`]: #method.copy
+	pub fn with_direct_access_mut<R, F: FnOnce(&mut [u8]) -> R>(&self, f: F) -> R {
+		let mut buf = self.buffer.borrow_mut();
+		f(&mut *buf)
+	}
 }
 
 pub fn validate_memory(initial: Pages, maximum: Option<Pages>) -> Result<(), String> {
@@ -369,6 +398,7 @@ mod tests {
 
 	#[test]
 	fn alloc() {
+		#[cfg(target_pointer_width = "64")]
 		let fixtures = &[
 			(0, None, true),
 			(0, Some(0), true),
@@ -381,6 +411,17 @@ mod tests {
 			(65536, Some(0), false),
 			(65536, None, true),
 		];
+
+		#[cfg(target_pointer_width = "32")]
+		let fixtures = &[
+			(0, None, true),
+			(0, Some(0), true),
+			(1, None, true),
+			(1, Some(1), true),
+			(0, Some(1), true),
+			(1, Some(0), false),
+		];
+
 		for (index, &(initial, maybe_max, expected_ok)) in fixtures.iter().enumerate() {
 			let initial: Pages = Pages(initial);
 			let maximum: Option<Pages> = maybe_max.map(|m| Pages(m));
@@ -472,4 +513,27 @@ mod tests {
 
 		assert_eq!(data, [17, 129]);
 	}
+
+	#[test]
+	fn zero_copy() {
+		let mem = MemoryInstance::alloc(Pages(1), None).unwrap();
+		mem.with_direct_access_mut(|buf| {
+			assert_eq!(buf.len(), 65536);
+			buf[..10].copy_from_slice(&[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+		});
+		mem.with_direct_access(|buf| {
+			assert_eq!(buf.len(), 65536);
+			assert_eq!(&buf[..10], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+		});
+	}
+
+	#[should_panic]
+	#[test]
+	fn zero_copy_panics_on_nested_access() {
+		let mem = MemoryInstance::alloc(Pages(1), None).unwrap();
+		let mem_inner = mem.clone();
+		mem.with_direct_access(move |_| {
+			let _ = mem_inner.set(0, &[11, 12, 13]);
+		});
+	}
 }

src/module.rs

@@ -291,7 +291,7 @@ impl ModuleInstance {
 			}
 		}
 
-		let labels = loaded_module.labels();
+		let code = loaded_module.code();
 		{
 			let funcs = module.function_section().map(|fs| fs.entries()).unwrap_or(
 				&[],
@@ -308,13 +308,12 @@ impl ModuleInstance {
 				let signature = instance.signature_by_index(ty.type_ref()).expect(
 					"Due to validation type should exists",
 				);
-				let labels = labels.get(&index).expect(
+				let code = code.get(index).expect(
 					"At func validation time labels are collected; Collected labels are added by index; qed",
 				).clone();
 				let func_body = FuncBody {
 					locals: body.locals().to_vec(),
-					opcodes: body.code().clone(),
-					labels: labels,
+					code: code,
 				};
 				let func_instance =
 					FuncInstance::alloc_internal(Rc::downgrade(&instance.0), signature, func_body);
@@ -420,7 +419,7 @@ impl ModuleInstance {
 
 			// This check is not only for bailing out early, but also to check the case when
 			// segment consist of 0 members.
-			if offset_val as usize + element_segment.members().len() > table_inst.current_size() as usize {
+			if offset_val as u64 + element_segment.members().len() as u64 > table_inst.current_size() as u64 {
 				return Err(
 					Error::Instantiation("elements segment does not fit".to_string())
 				);

src/validation/mod.rs

@@ -1,6 +1,6 @@
 use std::error;
 use std::fmt;
-use std::collections::{HashMap, HashSet};
+use std::collections::HashSet;
 use parity_wasm::elements::{
 	BlockType, External, GlobalEntry, GlobalType, Internal, MemoryType, Module, Opcode,
 	ResizableLimits, TableType, ValueType, InitExpr, Type
@@ -9,9 +9,11 @@ use common::stack;
 use self::context::ModuleContextBuilder;
 use self::func::Validator;
 use memory_units::Pages;
+use isa;
 
 mod context;
 mod func;
+mod util;
 
 #[cfg(test)]
 mod tests;
@@ -39,7 +41,7 @@ impl From<stack::Error> for Error {
 
 #[derive(Clone)]
 pub struct ValidatedModule {
-	pub labels: HashMap<usize, HashMap<usize, usize>>,
+	pub code_map: Vec<isa::Instructions>,
 	pub module: Module,
 }
 
@@ -50,10 +52,123 @@ impl ::std::ops::Deref for ValidatedModule {
 	}
 }
 
+pub fn deny_floating_point(module: &Module) -> Result<(), Error> {
+	if let Some(code) = module.code_section() {
+		for op in code.bodies().iter().flat_map(|body| body.code().elements()) {
+			use parity_wasm::elements::Opcode::*;
+
+			macro_rules! match_eq {
+				($pattern:pat) => {
+					|val| if let $pattern = *val { true } else { false }
+				};
+			}
+
+			const DENIED: &[fn(&Opcode) -> bool] = &[
+				match_eq!(F32Load(_, _)),
+				match_eq!(F64Load(_, _)),
+				match_eq!(F32Store(_, _)),
+				match_eq!(F64Store(_, _)),
+				match_eq!(F32Const(_)),
+				match_eq!(F64Const(_)),
+				match_eq!(F32Eq),
+				match_eq!(F32Ne),
+				match_eq!(F32Lt),
+				match_eq!(F32Gt),
+				match_eq!(F32Le),
+				match_eq!(F32Ge),
+				match_eq!(F64Eq),
+				match_eq!(F64Ne),
+				match_eq!(F64Lt),
+				match_eq!(F64Gt),
+				match_eq!(F64Le),
+				match_eq!(F64Ge),
+				match_eq!(F32Abs),
+				match_eq!(F32Neg),
+				match_eq!(F32Ceil),
+				match_eq!(F32Floor),
+				match_eq!(F32Trunc),
+				match_eq!(F32Nearest),
+				match_eq!(F32Sqrt),
+				match_eq!(F32Add),
+				match_eq!(F32Sub),
+				match_eq!(F32Mul),
+				match_eq!(F32Div),
+				match_eq!(F32Min),
+				match_eq!(F32Max),
+				match_eq!(F32Copysign),
+				match_eq!(F64Abs),
+				match_eq!(F64Neg),
+				match_eq!(F64Ceil),
+				match_eq!(F64Floor),
+				match_eq!(F64Trunc),
+				match_eq!(F64Nearest),
+				match_eq!(F64Sqrt),
+				match_eq!(F64Add),
+				match_eq!(F64Sub),
+				match_eq!(F64Mul),
+				match_eq!(F64Div),
+				match_eq!(F64Min),
+				match_eq!(F64Max),
+				match_eq!(F64Copysign),
+				match_eq!(F32ConvertSI32),
+				match_eq!(F32ConvertUI32),
+				match_eq!(F32ConvertSI64),
+				match_eq!(F32ConvertUI64),
+				match_eq!(F32DemoteF64),
+				match_eq!(F64ConvertSI32),
+				match_eq!(F64ConvertUI32),
+				match_eq!(F64ConvertSI64),
+				match_eq!(F64ConvertUI64),
+				match_eq!(F64PromoteF32),
+				match_eq!(F32ReinterpretI32),
+				match_eq!(F64ReinterpretI64),
+				match_eq!(I32TruncSF32),
+				match_eq!(I32TruncUF32),
+				match_eq!(I32TruncSF64),
+				match_eq!(I32TruncUF64),
+				match_eq!(I64TruncSF32),
+				match_eq!(I64TruncUF32),
+				match_eq!(I64TruncSF64),
+				match_eq!(I64TruncUF64),
+				match_eq!(I32ReinterpretF32),
+				match_eq!(I64ReinterpretF64),
+			];
+
+			if DENIED.iter().any(|is_denied| is_denied(op)) {
+				return Err(Error(format!("Floating point operation denied: {:?}", op)));
+			}
+		}
+	}
+
+	if let (Some(sec), Some(types)) = (module.function_section(), module.type_section()) {
+		use parity_wasm::elements::{Type, ValueType};
+
+		let types = types.types();
+
+		for sig in sec.entries() {
+			if let Some(typ) = types.get(sig.type_ref() as usize) {
+				match *typ {
+					Type::Function(ref func) => {
+						if func.params()
+							.iter()
+							.chain(func.return_type().as_ref())
+							.any(|&typ| typ == ValueType::F32 || typ == ValueType::F64)
+						{
+							return Err(Error(format!("Use of floating point types denied")));
+						}
+					}
+				}
+			}
+		}
+	}
+
+	Ok(())
+}
+
 pub fn validate_module(module: Module) -> Result<ValidatedModule, Error> {
 	let mut context_builder = ModuleContextBuilder::new();
 	let mut imported_globals = Vec::new();
-	let mut labels = HashMap::new();
+	let mut code_map = Vec::new();
 
 	// Copy types from module as is.
 	context_builder.set_types(
@@ -143,12 +258,12 @@ pub fn validate_module(module: Module) -> Result<ValidatedModule, Error> {
 					index
 				)),
 			)?;
-			let func_labels = Validator::validate_function(&context, function, function_body)
+			let code = Validator::validate_function(&context, function, function_body)
 				.map_err(|e| {
 					let Error(ref msg) = e;
 					Error(format!("Function #{} validation error: {}", index, msg))
 				})?;
-			labels.insert(index, func_labels);
+			code_map.push(code);
 		}
 	}
 
@@ -260,7 +375,7 @@ pub fn validate_module(module: Module) -> Result<ValidatedModule, Error> {
 
 	Ok(ValidatedModule {
 		module,
-		labels
+		code_map,
 	})
 }
 

src/validation/tests.rs

@@ -1,9 +1,12 @@
-use super::validate_module;
+use super::{validate_module, ValidatedModule};
 use parity_wasm::builder::module;
 use parity_wasm::elements::{
 	External, GlobalEntry, GlobalType, ImportEntry, InitExpr, MemoryType,
-    Opcode, Opcodes, TableType, ValueType, BlockType
+	Opcode, Opcodes, TableType, ValueType, BlockType, deserialize_buffer,
+	Module,
 };
+use isa;
+use wabt;
 
 #[test]
 fn empty_is_valid() {
@@ -299,3 +302,584 @@ fn if_else_with_return_type_validation() {
 		.build();
 	validate_module(m).unwrap();
 }
+
+fn validate(wat: &str) -> ValidatedModule {
+	let wasm = wabt::wat2wasm(wat).unwrap();
+	let module = deserialize_buffer::<Module>(&wasm).unwrap();
+	let validated_module = validate_module(module).unwrap();
+	validated_module
+}
+
+fn compile(wat: &str) -> Vec<isa::Instruction> {
+	let validated_module = validate(wat);
+	let code = &validated_module.code_map[0];
+	code.code.clone()
+}
+
+#[test]
+fn implicit_return_no_value() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 0,
+			}
+		]
+	)
+}
+
+#[test]
+fn implicit_return_with_value() {
+	let code = compile(r#"
+		(module
+			(func (export "call") (result i32)
+				i32.const 0
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(0),
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 1,
+			}
+		]
+	)
+}
+
+#[test]
+fn implicit_return_param() {
+	let code = compile(r#"
+		(module
+			(func (export "call") (param i32)
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::Return {
+				drop: 1,
+				keep: 0,
+			}
+		]
+	)
+}
+
+#[test]
+fn get_local() {
+	let code = compile(r#"
+		(module
+			(func (export "call") (param i32) (result i32)
+				get_local 0
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::GetLocal(1),
+			isa::Instruction::Return {
+				drop: 1,
+				keep: 1,
+			}
+		]
+	)
+}
+
+#[test]
+fn explicit_return() {
+	let code = compile(r#"
+		(module
+			(func (export "call") (param i32) (result i32)
+				get_local 0
+				return
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::GetLocal(1),
+			isa::Instruction::Return {
+				drop: 1,
+				keep: 1,
+			},
+			isa::Instruction::Return {
+				drop: 1,
+				keep: 1,
+			}
+		]
+	)
+}
+
+#[test]
+fn add_params() {
+	let code = compile(r#"
+		(module
+			(func (export "call") (param i32) (param i32) (result i32)
+				get_local 0
+				get_local 1
+				i32.add
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			// This is tricky. Locals are now loaded from the stack. The load
+			// happens from address relative of the current stack pointer. The first load
+			// takes the value below the previous one (i.e the second argument) and then, it increments
+			// the stack pointer. And then the same thing hapens with the value below the previous one
+			// (which happens to be the value loaded by the first get_local).
+			isa::Instruction::GetLocal(2),
+			isa::Instruction::GetLocal(2),
+			isa::Instruction::I32Add,
+			isa::Instruction::Return {
+				drop: 2,
+				keep: 1,
+			}
+		]
+	)
+}
+
+#[test]
+fn drop_locals() {
+	let code = compile(r#"
+		(module
+			(func (export "call") (param i32)
+				(local i32)
+				get_local 0
+				set_local 1
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::GetLocal(2),
+			isa::Instruction::SetLocal(1),
+			isa::Instruction::Return {
+				drop: 2,
+				keep: 0,
+			}
+		]
+	)
+}
+
+#[test]
+fn if_without_else() {
+	let code = compile(r#"
+		(module
+			(func (export "call") (param i32) (result i32)
+				i32.const 1
+				if
+					i32.const 2
+					return
+				end
+				i32.const 3
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrIfEqz(isa::Target {
+				dst_pc: 4,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(2),
+			isa::Instruction::Return {
+				drop: 1, // 1 param
+				keep: 1, // 1 result
+			},
+			isa::Instruction::I32Const(3),
+			isa::Instruction::Return {
+				drop: 1,
+				keep: 1,
+			},
+		]
+	)
+}
+
+#[test]
+fn if_else() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+				(local i32)
+				i32.const 1
+				if
+					i32.const 2
+					set_local 0
+				else
+					i32.const 3
+					set_local 0
+				end
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrIfEqz(isa::Target {
+				dst_pc: 5,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(2),
+			isa::Instruction::SetLocal(1),
+			isa::Instruction::Br(isa::Target {
+				dst_pc: 7,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(3),
+			isa::Instruction::SetLocal(1),
+			isa::Instruction::Return {
+				drop: 1,
+				keep: 0,
+			},
+		]
+	)
+}
+
+#[test]
+fn if_else_returns_result() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+				i32.const 1
+				if (result i32)
+					i32.const 2
+				else
+					i32.const 3
+				end
+				drop
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrIfEqz(isa::Target {
+				dst_pc: 4,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(2),
+			isa::Instruction::Br(isa::Target {
+				dst_pc: 5,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(3),
+			isa::Instruction::Drop,
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 0,
+			},
+		]
+	)
+}
+
+#[test]
+fn if_else_branch_from_true_branch() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+				i32.const 1
+				if (result i32)
+					i32.const 1
+					i32.const 1
+					br_if 0
+					drop
+					i32.const 2
+				else
+					i32.const 3
+				end
+				drop
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrIfEqz(isa::Target {
+				dst_pc: 8,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(1),
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrIfNez(isa::Target {
+				dst_pc: 9,
+				drop: 0,
+				keep: 1,
+			}),
+			isa::Instruction::Drop,
+			isa::Instruction::I32Const(2),
+			isa::Instruction::Br(isa::Target {
+				dst_pc: 9,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(3),
+			isa::Instruction::Drop,
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 0,
+			},
+		]
+	)
+}
+
+#[test]
+fn if_else_branch_from_false_branch() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+				i32.const 1
+				if (result i32)
+					i32.const 1
+				else
+					i32.const 2
+					i32.const 1
+					br_if 0
+					drop
+					i32.const 3
+				end
+				drop
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrIfEqz(isa::Target {
+				dst_pc: 4,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(1),
+			isa::Instruction::Br(isa::Target {
+				dst_pc: 9,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(2),
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrIfNez(isa::Target {
+				dst_pc: 9,
+				drop: 0,
+				keep: 1,
+			}),
+			isa::Instruction::Drop,
+			isa::Instruction::I32Const(3),
+			isa::Instruction::Drop,
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 0,
+			},
+		]
+	)
+}
+
+#[test]
+fn loop_() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+				loop (result i32)
+					i32.const 1
+					br_if 0
+					i32.const 2
+				end
+				drop
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrIfNez(isa::Target {
+				dst_pc: 0,
+				drop: 0,
+				keep: 0,
+			}),
+			isa::Instruction::I32Const(2),
+			isa::Instruction::Drop,
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 0,
+			},
+		]
+	)
+}
+
+#[test]
+fn loop_empty() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+				loop
+				end
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 0,
+			},
+		]
+	)
+}
+
+#[test]
+fn brtable() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+				block $1
+					loop $2
+						i32.const 0
+						br_table $2 $1
+					end
+				end
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(0),
+			isa::Instruction::BrTable(
+				vec![
+					isa::Target {
+						dst_pc: 0,
+						keep: 0,
+						drop: 0,
+					},
+					isa::Target {
+						dst_pc: 2,
+						keep: 0,
+						drop: 0,
+					},
+				].into_boxed_slice()
+			),
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 0,
+			},
+		]
+	)
+}
+
+#[test]
+fn brtable_returns_result() {
+	let code = compile(r#"
+		(module
+			(func (export "call")
+				block $1 (result i32)
+					block $2 (result i32)
+						i32.const 0
+						i32.const 1
+						br_table $2 $1
+					end
+					unreachable
+				end
+				drop
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::I32Const(0),
+			isa::Instruction::I32Const(1),
+			isa::Instruction::BrTable(
+				vec![
+					isa::Target {
+						dst_pc: 3,
+						keep: 1,
+						drop: 0,
+					},
+					isa::Target {
+						dst_pc: 4,
+						keep: 1,
+						drop: 0,
+					},
+				].into_boxed_slice()
+			),
+			isa::Instruction::Unreachable,
+			isa::Instruction::Drop,
+			isa::Instruction::Return {
+				drop: 0,
+				keep: 0,
+			},
+		]
+	)
+}
+
+#[test]
+fn wabt_example() {
+	let code = compile(r#"
+		(module
+			(func (export "call") (param i32) (result i32)
+				block $exit
+					get_local 0
+					br_if $exit
+					i32.const 1
+					return
+				end
+				i32.const 2
+				return
+			)
+		)
+	"#);
+	assert_eq!(
+		code,
+		vec![
+			isa::Instruction::GetLocal(1),
+			isa::Instruction::BrIfNez(isa::Target {
+				dst_pc: 4,
+				keep: 0,
+				drop: 0,
+			}),
+			isa::Instruction::I32Const(1),
+			isa::Instruction::Return {
+				drop: 1, // 1 parameter
+				keep: 1, // return value
+			},
+			isa::Instruction::I32Const(2),
+			isa::Instruction::Return {
+				drop: 1,
+				keep: 1,
+			},
+			isa::Instruction::Return {
+				drop: 1,
+				keep: 1,
+			},
+		]
+	)
+}
+

src/validation/util.rs

@@ -0,0 +1,132 @@
+use parity_wasm::elements::{Local, ValueType};
+use validation::Error;
+
+/// Locals are the concatenation of a slice of function parameters
+/// with function declared local variables.
+///
+/// Local variables are given in the form of groups represented by pairs
+/// of a value_type and a count.
+#[derive(Debug)]
+pub struct Locals<'a> {
+	params: &'a [ValueType],
+	local_groups: &'a [Local],
+}
+
+impl<'a> Locals<'a> {
+	pub fn new(params: &'a [ValueType], local_groups: &'a [Local]) -> Locals<'a> {
+		Locals {
+			params,
+			local_groups,
+		}
+	}
+
+	/// Returns parameter count.
+	pub fn param_count(&self) -> u32 {
+		self.params.len() as u32
+	}
+
+	/// Returns total count of all declared locals and paramaterers.
+	///
+	/// Returns `Err` if count overflows 32-bit value.
+	pub fn count(&self) -> Result<u32, Error> {
+		let mut acc = self.param_count();
+		for locals_group in self.local_groups {
+			acc = acc
+				.checked_add(locals_group.count())
+				.ok_or_else(||
+					Error(String::from("Locals range no in 32-bit range"))
+				)?;
+		}
+		Ok(acc)
+	}
+
+	/// Returns the type of a local variable (either a declared local or a param).
+	///
+	/// Returns `Err` in the case of overflow or when idx falls out of range.
+	pub fn type_of_local(&self, idx: u32) -> Result<ValueType, Error> {
+		if let Some(param) = self.params.get(idx as usize) {
+			return Ok(*param);
+		}
+
+		// If an index doesn't point to a param, then we have to look into local declarations.
+		let mut start_idx = self.param_count();
+		for locals_group in self.local_groups {
+			let end_idx = start_idx
+				.checked_add(locals_group.count())
+				.ok_or_else(|| Error(String::from("Locals range not in 32-bit range")))?;
+
+			if idx >= start_idx && idx < end_idx {
+				return Ok(locals_group.value_type());
+			}
+
+			start_idx = end_idx;
+		}
+
+		// We didn't find anything, that's an error.
+		// At this moment `start_idx` should hold the count of all locals
+		// (since it's either set to the `end_idx` or equal to `params.len()`)
+		let total_count = start_idx;
+
+		Err(Error(format!(
+			"Trying to access local with index {} when there are only {} locals",
+			idx, total_count
+		)))
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn locals_it_works() {
+		let params = vec![ValueType::I32, ValueType::I64];
+		let local_groups = vec![Local::new(2, ValueType::F32), Local::new(2, ValueType::F64)];
+		let locals = Locals::new(&params, &local_groups);
+
+		assert_matches!(locals.type_of_local(0), Ok(ValueType::I32));
+		assert_matches!(locals.type_of_local(1), Ok(ValueType::I64));
+		assert_matches!(locals.type_of_local(2), Ok(ValueType::F32));
+		assert_matches!(locals.type_of_local(3), Ok(ValueType::F32));
+		assert_matches!(locals.type_of_local(4), Ok(ValueType::F64));
+		assert_matches!(locals.type_of_local(5), Ok(ValueType::F64));
+		assert_matches!(locals.type_of_local(6), Err(_));
+	}
+
+	#[test]
+	fn locals_no_declared_locals() {
+		let params = vec![ValueType::I32];
+		let locals = Locals::new(&params, &[]);
+
+		assert_matches!(locals.type_of_local(0), Ok(ValueType::I32));
+		assert_matches!(locals.type_of_local(1), Err(_));
+	}
+
+	#[test]
+	fn locals_no_params() {
+		let local_groups = vec![Local::new(2, ValueType::I32), Local::new(3, ValueType::I64)];
+		let locals = Locals::new(&[], &local_groups);
+
+		assert_matches!(locals.type_of_local(0), Ok(ValueType::I32));
+		assert_matches!(locals.type_of_local(1), Ok(ValueType::I32));
+		assert_matches!(locals.type_of_local(2), Ok(ValueType::I64));
+		assert_matches!(locals.type_of_local(3), Ok(ValueType::I64));
+		assert_matches!(locals.type_of_local(4), Ok(ValueType::I64));
+		assert_matches!(locals.type_of_local(5), Err(_));
+	}
+
+	#[test]
+	fn locals_u32_overflow() {
+		let local_groups = vec![
+			Local::new(u32::max_value(), ValueType::I32),
+			Local::new(1, ValueType::I64),
+		];
+		let locals = Locals::new(&[], &local_groups);
+
+		assert_matches!(
+			locals.type_of_local(u32::max_value() - 1),
+			Ok(ValueType::I32)
+		);
+		assert_matches!(locals.type_of_local(u32::max_value()), Err(_));
+	}
+}

src/value.rs

@@ -1,6 +1,7 @@
-use std::{i32, i64, u32, u64, f32};
-use std::io;
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
+use nan_preserving_float::{F32, F64};
+use std::io;
+use std::{f32, i32, i64, u32, u64};
 use TrapKind;
 
 #[derive(Debug)]
@@ -22,9 +23,9 @@ pub enum RuntimeValue {
 	/// Value of 64-bit signed or unsigned integer.
 	I64(i64),
 	/// Value of 32-bit IEEE 754-2008 floating point number.
-	F32(f32),
+	F32(F32),
 	/// Value of 64-bit IEEE 754-2008 floating point number.
-	F64(f64),
+	F64(F64),
 }
 
 /// Trait for creating value from a [`RuntimeValue`].
@@ -136,19 +137,19 @@ impl RuntimeValue {
 		match value_type {
 			::types::ValueType::I32 => RuntimeValue::I32(0),
 			::types::ValueType::I64 => RuntimeValue::I64(0),
-			::types::ValueType::F32 => RuntimeValue::F32(0f32),
-			::types::ValueType::F64 => RuntimeValue::F64(0f64),
+			::types::ValueType::F32 => RuntimeValue::F32(0f32.into()),
+			::types::ValueType::F64 => RuntimeValue::F64(0f64.into()),
 		}
 	}
 
 	/// Creates new value by interpreting passed u32 as f32.
 	pub fn decode_f32(val: u32) -> Self {
-		RuntimeValue::F32(f32::from_bits(val))
+		RuntimeValue::F32(F32::from_bits(val))
 	}
 
 	/// Creates new value by interpreting passed u64 as f64.
 	pub fn decode_f64(val: u64) -> Self {
-		RuntimeValue::F64(f64::from_bits(val))
+		RuntimeValue::F64(F64::from_bits(val))
 	}
 
 	/// Get variable type for this value.
@@ -197,14 +198,14 @@ impl From<u64> for RuntimeValue {
 	}
 }
 
-impl From<f32> for RuntimeValue {
-	fn from(val: f32) -> Self {
+impl From<F32> for RuntimeValue {
+	fn from(val: F32) -> Self {
 		RuntimeValue::F32(val)
 	}
 }
 
-impl From<f64> for RuntimeValue {
-	fn from(val: f64) -> Self {
+impl From<F64> for RuntimeValue {
+	fn from(val: F64) -> Self {
 		RuntimeValue::F64(val)
 	}
 }
@@ -214,7 +215,7 @@ macro_rules! impl_from_runtime_value {
 		impl FromRuntimeValue for $into {
 			fn from_runtime_value(val: RuntimeValue) -> Option<Self> {
 				match val {
-					RuntimeValue::$expected_rt_ty(val) => Some(val as $into),
+					RuntimeValue::$expected_rt_ty(val) => Some(val.transmute_into()),
 					_ => None,
 				}
 			}
@@ -237,19 +238,26 @@ impl FromRuntimeValue for bool {
 
 impl_from_runtime_value!(I32, i32);
 impl_from_runtime_value!(I64, i64);
-impl_from_runtime_value!(F32, f32);
-impl_from_runtime_value!(F64, f64);
+impl_from_runtime_value!(F32, F32);
+impl_from_runtime_value!(F64, F64);
 impl_from_runtime_value!(I32, u32);
 impl_from_runtime_value!(I64, u64);
 
 macro_rules! impl_wrap_into {
-	($from: ident, $into: ident) => {
+	($from:ident, $into:ident) => {
 		impl WrapInto<$into> for $from {
 			fn wrap_into(self) -> $into {
 				self as $into
 			}
 		}
+	};
+	($from:ident, $intermediate:ident, $into:ident) => {
+		impl WrapInto<$into> for $from {
+			fn wrap_into(self) -> $into {
+				$into::from(self as $intermediate)
 			}
+		}
+	};
 }
 
 impl_wrap_into!(i32, i8);
@@ -257,13 +265,19 @@ impl_wrap_into!(i32, i16);
 impl_wrap_into!(i64, i8);
 impl_wrap_into!(i64, i16);
 impl_wrap_into!(i64, i32);
-impl_wrap_into!(i64, f32);
-impl_wrap_into!(u64, f32);
+impl_wrap_into!(i64, f32, F32);
+impl_wrap_into!(u64, f32, F32);
 // Casting from an f64 to an f32 will produce the closest possible value (rounding strategy unspecified)
 // NOTE: currently this will cause Undefined Behavior if the value is finite but larger or smaller than the
 // largest or smallest finite value representable by f32. This is a bug and will be fixed.
 impl_wrap_into!(f64, f32);
 
+impl WrapInto<F32> for F64 {
+	fn wrap_into(self) -> F32 {
+		(f64::from(self) as f32).into()
+	}
+}
+
 macro_rules! impl_try_truncate_into {
 	($from: ident, $into: ident) => {
 		impl TryTruncateInto<$into, TrapKind> for $from {
@@ -284,7 +298,14 @@ macro_rules! impl_try_truncate_into {
 				Ok(self as $into)
 			}
 		}
+	};
+	($from:ident, $intermediate:ident, $into:ident) => {
+		impl TryTruncateInto<$into, TrapKind> for $from {
+			fn try_truncate_into(self) -> Result<$into, TrapKind> {
+				$intermediate::from(self).try_truncate_into()
 			}
+		}
+	};
 }
 
 impl_try_truncate_into!(f32, i32);
@@ -295,15 +316,30 @@ impl_try_truncate_into!(f32, u32);
 impl_try_truncate_into!(f32, u64);
 impl_try_truncate_into!(f64, u32);
 impl_try_truncate_into!(f64, u64);
+impl_try_truncate_into!(F32, f32, i32);
+impl_try_truncate_into!(F32, f32, i64);
+impl_try_truncate_into!(F64, f64, i32);
+impl_try_truncate_into!(F64, f64, i64);
+impl_try_truncate_into!(F32, f32, u32);
+impl_try_truncate_into!(F32, f32, u64);
+impl_try_truncate_into!(F64, f64, u32);
+impl_try_truncate_into!(F64, f64, u64);
 
 macro_rules! impl_extend_into {
-	($from: ident, $into: ident) => {
+	($from:ident, $into:ident) => {
 		impl ExtendInto<$into> for $from {
 			fn extend_into(self) -> $into {
 				self as $into
 			}
 		}
+	};
+	($from:ident, $intermediate:ident, $into:ident) => {
+		impl ExtendInto<$into> for $from {
+			fn extend_into(self) -> $into {
+				$into::from(self as $intermediate)
 			}
+		}
+	};
 }
 
 impl_extend_into!(i8, i32);
@@ -325,6 +361,20 @@ impl_extend_into!(i64, f64);
 impl_extend_into!(u64, f64);
 impl_extend_into!(f32, f64);
 
+impl_extend_into!(i32, f32, F32);
+impl_extend_into!(i32, f64, F64);
+impl_extend_into!(u32, f32, F32);
+impl_extend_into!(u32, f64, F64);
+impl_extend_into!(i64, f64, F64);
+impl_extend_into!(u64, f64, F64);
+impl_extend_into!(f32, f64, F64);
+
+impl ExtendInto<F64> for F32 {
+	fn extend_into(self) -> F64 {
+		(f32::from(self) as f64).into()
+	}
+}
+
 macro_rules! impl_transmute_into_self {
 	($type: ident) => {
 		impl TransmuteInto<$type> for $type {
@@ -339,6 +389,8 @@ impl_transmute_into_self!(i32);
 impl_transmute_into_self!(i64);
 impl_transmute_into_self!(f32);
 impl_transmute_into_self!(f64);
+impl_transmute_into_self!(F32);
+impl_transmute_into_self!(F64);
 
 macro_rules! impl_transmute_into_as {
 	($from: ident, $into: ident) => {
@@ -357,6 +409,49 @@ impl_transmute_into_as!(u32, i32);
 impl_transmute_into_as!(i64, u64);
 impl_transmute_into_as!(u64, i64);
 
+macro_rules! impl_transmute_into_npf {
+	($npf:ident, $float:ident, $signed:ident, $unsigned:ident) => {
+		impl TransmuteInto<$float> for $npf {
+			fn transmute_into(self) -> $float {
+				self.into()
+			}
+		}
+
+		impl TransmuteInto<$npf> for $float {
+			fn transmute_into(self) -> $npf {
+				self.into()
+			}
+		}
+
+		impl TransmuteInto<$signed> for $npf {
+			fn transmute_into(self) -> $signed {
+				self.to_bits() as _
+			}
+		}
+
+		impl TransmuteInto<$unsigned> for $npf {
+			fn transmute_into(self) -> $unsigned {
+				self.to_bits()
+			}
+		}
+
+		impl TransmuteInto<$npf> for $signed {
+			fn transmute_into(self) -> $npf {
+				$npf::from_bits(self as _)
+			}
+		}
+
+		impl TransmuteInto<$npf> for $unsigned {
+			fn transmute_into(self) -> $npf {
+				$npf::from_bits(self)
+			}
+		}
+	};
+}
+
+impl_transmute_into_npf!(F32, f32, i32, u32);
+impl_transmute_into_npf!(F64, f64, i64, u64);
+
 impl TransmuteInto<i32> for f32 {
 	fn transmute_into(self) -> i32 { self.to_bits() as i32 }
 }
@@ -497,6 +592,26 @@ impl LittleEndianConvert for f64 {
 	}
 }
 
+impl LittleEndianConvert for F32 {
+	fn into_little_endian(self) -> Vec<u8> {
+		(self.to_bits() as i32).into_little_endian()
+	}
+
+	fn from_little_endian(buffer: &[u8]) -> Result<Self, Error> {
+		i32::from_little_endian(buffer).map(|val| Self::from_bits(val as _))
+	}
+}
+
+impl LittleEndianConvert for F64 {
+	fn into_little_endian(self) -> Vec<u8> {
+		(self.to_bits() as i64).into_little_endian()
+	}
+
+	fn from_little_endian(buffer: &[u8]) -> Result<Self, Error> {
+		i64::from_little_endian(buffer).map(|val| Self::from_bits(val as _))
+	}
+}
+
 macro_rules! impl_integer_arithmetic_ops {
 	($type: ident) => {
 		impl ArithmeticOps<$type> for $type {
@@ -538,6 +653,8 @@ macro_rules! impl_float_arithmetic_ops {
 
 impl_float_arithmetic_ops!(f32);
 impl_float_arithmetic_ops!(f64);
+impl_float_arithmetic_ops!(F32);
+impl_float_arithmetic_ops!(F64);
 
 macro_rules! impl_integer {
 	($type: ident) => {
@@ -561,13 +678,26 @@ impl_integer!(i64);
 impl_integer!(u64);
 
 macro_rules! impl_float {
-	($type: ident, $int_type: ident) => {
+	($type:ident, $int_type:ident) => {
+		impl_float!($type, $type, $int_type);
+	};
+	($type:ident, $intermediate:ident, $int_type:ident) => {
 		impl Float<$type> for $type {
-			fn abs(self) -> $type { self.abs() }
-			fn floor(self) -> $type { self.floor() }
-			fn ceil(self) -> $type { self.ceil() }
-			fn trunc(self) -> $type { self.trunc() }
-			fn round(self) -> $type { self.round() }
+			fn abs(self) -> $type {
+				$intermediate::abs(self.into()).into()
+			}
+			fn floor(self) -> $type {
+				$intermediate::floor(self.into()).into()
+			}
+			fn ceil(self) -> $type {
+				$intermediate::ceil(self.into()).into()
+			}
+			fn trunc(self) -> $type {
+				$intermediate::trunc(self.into()).into()
+			}
+			fn round(self) -> $type {
+				$intermediate::round(self.into()).into()
+			}
 			fn nearest(self) -> $type {
 				let round = self.round();
 				if self.fract().abs() != 0.5 {
@@ -583,12 +713,13 @@ macro_rules! impl_float {
 					round
 				}
 			}
-			fn sqrt(self) -> $type { self.sqrt() }
+			fn sqrt(self) -> $type {
+				$intermediate::sqrt(self.into()).into()
+			}
 			// This instruction corresponds to what is sometimes called "minNaN" in other languages.
 			fn min(self, other: $type) -> $type {
 				if self.is_nan() || other.is_nan() {
-					use std::$type;
-					return $type::NAN;
+					return ::std::$intermediate::NAN.into();
 				}
 
 				self.min(other)
@@ -596,8 +727,7 @@ macro_rules! impl_float {
 			// This instruction corresponds to what is sometimes called "maxNaN" in other languages.
 			fn max(self, other: $type) -> $type {
 				if self.is_nan() || other.is_nan() {
-					use std::$type;
-					return $type::NAN;
+					return ::std::$intermediate::NAN.into();
 				}
 
 				self.max(other)
@@ -623,8 +753,10 @@ macro_rules! impl_float {
 				}
 			}
 		}
-	}
+	};
 }
 
 impl_float!(f32, i32);
 impl_float!(f64, i64);
+impl_float!(F32, f32, i32);
+impl_float!(F64, f64, i64);

tests/spec/run.rs

@@ -2,21 +2,19 @@
 
 use std::collections::HashMap;
 
-use wasmi::{
-    Error as InterpreterError, Externals, FuncInstance, FuncRef, GlobalDescriptor,
+use wabt::script::{self, Action, Command, CommandKind, ScriptParser, Value};
+use wasmi::memory_units::Pages;
+use wasmi::{Error as InterpreterError, Externals, FuncInstance, FuncRef, GlobalDescriptor,
             GlobalInstance, GlobalRef, ImportResolver, ImportsBuilder, MemoryDescriptor,
             MemoryInstance, MemoryRef, Module, ModuleImportResolver, ModuleInstance, ModuleRef,
-    RuntimeArgs, RuntimeValue, Signature, TableDescriptor, TableInstance, TableRef, Trap,
-};
-use wasmi::memory_units::Pages;
-use wabt::script::{self, Action, Command, CommandKind, ScriptParser, Value};
+            RuntimeArgs, RuntimeValue, Signature, TableDescriptor, TableInstance, TableRef, Trap};
 
-fn spec_to_runtime_value(value: Value) -> RuntimeValue {
-    match value {
+fn spec_to_runtime_value(val: Value<u32, u64>) -> RuntimeValue {
+	match val {
 		Value::I32(v) => RuntimeValue::I32(v),
 		Value::I64(v) => RuntimeValue::I64(v),
-        Value::F32(v) => RuntimeValue::F32(v),
-        Value::F64(v) => RuntimeValue::F64(v),
+		Value::F32(v) => RuntimeValue::F32(v.into()),
+		Value::F64(v) => RuntimeValue::F64(v.into()),
 	}
 }
 
@@ -54,8 +52,8 @@ impl SpecModule {
 			table: TableInstance::alloc(10, Some(20)).unwrap(),
 			memory: MemoryInstance::alloc(Pages(1), Some(Pages(2))).unwrap(),
 			global_i32: GlobalInstance::alloc(RuntimeValue::I32(666), false),
-            global_f32: GlobalInstance::alloc(RuntimeValue::F32(666.0), false),
-            global_f64: GlobalInstance::alloc(RuntimeValue::F64(666.0), false),
+			global_f32: GlobalInstance::alloc(RuntimeValue::F32(666.0.into()), false),
+			global_f64: GlobalInstance::alloc(RuntimeValue::F64(666.0.into()), false),
 		}
 	}
 }
@@ -121,7 +119,7 @@ impl ModuleImportResolver for SpecModule {
 			_ => Err(InterpreterError::Instantiation(format!(
 				"Unknown host global import {}",
 				field_name
-			)))
+			))),
 		}
 	}
 
@@ -269,7 +267,11 @@ fn try_load(wasm: &[u8], spec_driver: &mut SpecDriver) -> Result<(), Error> {
 	Ok(())
 }
 
-fn load_module(wasm: &[u8], name: &Option<String>, spec_driver: &mut SpecDriver) -> Result<ModuleRef, Error> {
+fn load_module(
+	wasm: &[u8],
+	name: &Option<String>,
+	spec_driver: &mut SpecDriver,
+) -> Result<ModuleRef, Error> {
 	let module = try_load_module(wasm)?;
 	let instance = ModuleInstance::new(&module, spec_driver)
 		.map_err(|e| Error::Load(e.to_string()))?
@@ -284,7 +286,7 @@ fn load_module(wasm: &[u8], name: &Option<String>, spec_driver: &mut SpecDriver)
 
 fn run_action(
 	program: &mut SpecDriver,
-    action: &Action,
+	action: &Action<u32, u64>,
 ) -> Result<Option<RuntimeValue>, InterpreterError> {
 	match *action {
 		Action::Invoke {
@@ -298,14 +300,11 @@ fn run_action(
 					"Expected program to have loaded module {:?}",
 					module
 				));
-            module.invoke_export(
-                field,
-                &args.iter()
+			let vec_args = args.iter()
 				.cloned()
 				.map(spec_to_runtime_value)
-                    .collect::<Vec<_>>(),
-                program.spec_module(),
-            )
+				.collect::<Vec<_>>();
+			module.invoke_export(field, &vec_args, program.spec_module())
 		}
 		Action::Get {
 			ref module,
@@ -342,11 +341,31 @@ fn try_spec(name: &str) -> Result<(), Error> {
 	let mut spec_driver = SpecDriver::new();
 	let spec_script_path = format!("tests/spec/testsuite/{}.wast", name);
 	let mut parser = ScriptParser::from_file(spec_script_path).expect("Can't read spec script");
+	let mut errors = vec![];
+
 	while let Some(Command { kind, line }) = parser.next()? {
-		println!("Line {}:", line);
+		macro_rules! assert_eq {
+			($a:expr, $b:expr) => {{
+				let (a, b) = ($a, $b);
+
+				if a != b {
+					errors.push(format!(
+						r#"ERROR (line {}):
+  expected: {:?}
+  got:      {:?}
+"#,
+						line, b, a,
+					));
+					}
+				}};
+		}
+
+		println!("Running spec cmd {}: {:?}", line, kind);
+
 		match kind {
 			CommandKind::Module { name, module, .. } => {
-                load_module(&module.into_vec()?, &name, &mut spec_driver).expect("Failed to load module");
+				load_module(&module.into_vec()?, &name, &mut spec_driver)
+					.expect("Failed to load module");
 			}
 			CommandKind::AssertReturn { action, expected } => {
 				let result = run_action(&mut spec_driver, &action);
@@ -375,7 +394,6 @@ fn try_spec(name: &str) -> Result<(), Error> {
 								spec_expected @ _ => assert_eq!(actual_result, spec_expected),
 							}
 						}
-                        println!("assert_return at line {} - success", line);
 					}
 					Err(e) => {
 						panic!("Expected action to return value, got error: {:?}", e);
@@ -400,7 +418,6 @@ fn try_spec(name: &str) -> Result<(), Error> {
 								}
 							}
 						}
-                        println!("assert_return_nan at line {} - success", line);
 					}
 					Err(e) => {
 						panic!("Expected action to return value, got error: {:?}", e);
@@ -411,7 +428,7 @@ fn try_spec(name: &str) -> Result<(), Error> {
 				let result = run_action(&mut spec_driver, &action);
 				match result {
 					Ok(result) => panic!("Expected exhaustion, got result: {:?}", result),
-                    Err(e) => println!("assert_exhaustion at line {} - success ({:?})", line, e),
+					Err(_e) => {},
 				}
 			}
 			CommandKind::AssertTrap { action, .. } => {
@@ -423,9 +440,7 @@ fn try_spec(name: &str) -> Result<(), Error> {
 							result
 						);
 					}
-                    Err(e) => {
-                        println!("assert_trap at line {} - success ({:?})", line, e);
-                    }
+					Err(_e) => {}
 				}
 			}
 			CommandKind::AssertInvalid { module, .. }
@@ -434,13 +449,13 @@ fn try_spec(name: &str) -> Result<(), Error> {
 				let module_load = try_load(&module.into_vec()?, &mut spec_driver);
 				match module_load {
 					Ok(_) => panic!("Expected invalid module definition, got some module!"),
-                    Err(e) => println!("assert_invalid at line {} - success ({:?})", line, e),
+					Err(_e) => {},
 				}
 			}
 			CommandKind::AssertUninstantiable { module, .. } => {
 				match try_load(&module.into_vec()?, &mut spec_driver) {
 					Ok(_) => panic!("Expected error running start function at line {}", line),
-                    Err(e) => println!("assert_uninstantiable - success ({:?})", e),
+					Err(_e) => {},
 				}
 			}
 			CommandKind::Register { name, as_name, .. } => {
@@ -457,5 +472,14 @@ fn try_spec(name: &str) -> Result<(), Error> {
 		}
 	}
 
+	if !errors.is_empty() {
+		use std::fmt::Write;
+		let mut out = "\n".to_owned();
+		for err in errors {
+			write!(out, "{}", err).expect("Error formatting errors");
+		}
+		panic!(out);
+	}
+
 	Ok(())
 }