Files
wasmtime/crates/wast/src/wast.rs
2020-12-07 10:59:55 -08:00

686 lines
25 KiB
Rust

use crate::spectest::link_spectest;
use anyhow::{anyhow, bail, Context as _, Result};
use core::fmt;
use std::str;
use std::{mem::size_of_val, path::Path};
use wasmtime::*;
use wast::Wat;
use wast::{
parser::{self, ParseBuffer},
HeapType,
};
/// Translate from a `script::Value` to a `RuntimeValue`.
fn runtime_value(v: &wast::Expression<'_>) -> Result<Val> {
use wast::Instruction::*;
if v.instrs.len() != 1 {
bail!("too many instructions in {:?}", v);
}
Ok(match &v.instrs[0] {
I32Const(x) => Val::I32(*x),
I64Const(x) => Val::I64(*x),
F32Const(x) => Val::F32(x.bits),
F64Const(x) => Val::F64(x.bits),
V128Const(x) => Val::V128(u128::from_le_bytes(x.to_le_bytes())),
RefNull(HeapType::Extern) => Val::ExternRef(None),
RefNull(HeapType::Func) => Val::FuncRef(None),
RefExtern(x) => Val::ExternRef(Some(ExternRef::new(*x))),
other => bail!("couldn't convert {:?} to a runtime value", other),
})
}
/// The wast test script language allows modules to be defined and actions
/// to be performed on them.
pub struct WastContext {
/// Wast files have a concept of a "current" module, which is the most
/// recently defined.
current: Option<Instance>,
// FIXME(#1479) this is only needed to retain correct trap information after
// we've dropped previous `Instance` values.
modules: Vec<Module>,
linker: Linker,
store: Store,
}
enum Outcome<T = Vec<Val>> {
Ok(T),
Trap(Trap),
}
impl<T> Outcome<T> {
fn into_result(self) -> Result<T, Trap> {
match self {
Outcome::Ok(t) => Ok(t),
Outcome::Trap(t) => Err(t),
}
}
}
impl WastContext {
/// Construct a new instance of `WastContext`.
pub fn new(store: Store) -> Self {
// Spec tests will redefine the same module/name sometimes, so we need
// to allow shadowing in the linker which picks the most recent
// definition as what to link when linking.
let mut linker = Linker::new(&store);
linker.allow_shadowing(true);
Self {
current: None,
linker,
store,
modules: Vec::new(),
}
}
fn get_export(&self, module: Option<&str>, name: &str) -> Result<Extern> {
match module {
Some(module) => self.linker.get_one_by_name(module, Some(name)),
None => self
.current
.as_ref()
.ok_or_else(|| anyhow!("no previous instance found"))?
.get_export(name)
.ok_or_else(|| anyhow!("no item named `{}` found", name)),
}
}
fn instantiate(&mut self, module: &[u8]) -> Result<Outcome<Instance>> {
let module = Module::new(self.store.engine(), module)?;
self.modules.push(module.clone());
let instance = match self.linker.instantiate(&module) {
Ok(i) => i,
Err(e) => return e.downcast::<Trap>().map(Outcome::Trap),
};
Ok(Outcome::Ok(instance))
}
/// Register "spectest" which is used by the spec testsuite.
pub fn register_spectest(&mut self) -> Result<()> {
link_spectest(&mut self.linker)?;
Ok(())
}
/// Perform the action portion of a command.
fn perform_execute(&mut self, exec: wast::WastExecute<'_>) -> Result<Outcome> {
match exec {
wast::WastExecute::Invoke(invoke) => self.perform_invoke(invoke),
wast::WastExecute::Module(mut module) => {
let binary = module.encode()?;
let result = self.instantiate(&binary)?;
Ok(match result {
Outcome::Ok(_) => Outcome::Ok(Vec::new()),
Outcome::Trap(e) => Outcome::Trap(e),
})
}
wast::WastExecute::Get { module, global } => self.get(module.map(|s| s.name()), global),
}
}
fn perform_invoke(&mut self, exec: wast::WastInvoke<'_>) -> Result<Outcome> {
let values = exec
.args
.iter()
.map(|v| runtime_value(v))
.collect::<Result<Vec<_>>>()?;
self.invoke(exec.module.map(|i| i.name()), exec.name, &values)
}
/// Define a module and register it.
fn module(&mut self, instance_name: Option<&str>, module: &[u8]) -> Result<()> {
let instance = match self.instantiate(module)? {
Outcome::Ok(i) => i,
Outcome::Trap(e) => return Err(e).context("instantiation failed"),
};
if let Some(name) = instance_name {
self.linker.instance(name, &instance)?;
}
self.current = Some(instance);
Ok(())
}
/// Register an instance to make it available for performing actions.
fn register(&mut self, name: Option<&str>, as_name: &str) -> Result<()> {
match name {
Some(name) => self.linker.alias(name, as_name),
None => {
let current = self
.current
.as_ref()
.ok_or(anyhow!("no previous instance"))?;
self.linker.instance(as_name, current)?;
Ok(())
}
}
}
/// Invoke an exported function from an instance.
fn invoke(
&mut self,
instance_name: Option<&str>,
field: &str,
args: &[Val],
) -> Result<Outcome> {
let func = self
.get_export(instance_name, field)?
.into_func()
.ok_or_else(|| anyhow!("no function named `{}`", field))?;
Ok(match func.call(args) {
Ok(result) => Outcome::Ok(result.into()),
Err(e) => Outcome::Trap(e.downcast()?),
})
}
/// Get the value of an exported global from an instance.
fn get(&mut self, instance_name: Option<&str>, field: &str) -> Result<Outcome> {
let global = self
.get_export(instance_name, field)?
.into_global()
.ok_or_else(|| anyhow!("no global named `{}`", field))?;
Ok(Outcome::Ok(vec![global.get()]))
}
fn assert_return(&self, result: Outcome, results: &[wast::AssertExpression]) -> Result<()> {
let values = result.into_result()?;
for (v, e) in values.iter().zip(results) {
if val_matches(v, e)? {
continue;
}
bail!(
"expected {:?} ({}), got {:?} ({})",
e,
e.as_hex_pattern(),
v,
v.as_hex_pattern()
)
}
Ok(())
}
fn assert_trap(&self, result: Outcome, expected: &str) -> Result<()> {
let trap = match result {
Outcome::Ok(values) => bail!("expected trap, got {:?}", values),
Outcome::Trap(t) => t,
};
let actual = trap.to_string();
if actual.contains(expected)
// `bulk-memory-operations/bulk.wast` checks for a message that
// specifies which element is uninitialized, but our traps don't
// shepherd that information out.
|| (expected.contains("uninitialized element 2") && actual.contains("uninitialized element"))
{
return Ok(());
}
if cfg!(feature = "lightbeam") {
println!("TODO: Check the assert_trap message: {}", expected);
return Ok(());
}
bail!("expected '{}', got '{}'", expected, actual)
}
/// Run a wast script from a byte buffer.
pub fn run_buffer(&mut self, filename: &str, wast: &[u8]) -> Result<()> {
let wast = str::from_utf8(wast)?;
let adjust_wast = |mut err: wast::Error| {
err.set_path(filename.as_ref());
err.set_text(wast);
err
};
let buf = wast::parser::ParseBuffer::new(wast).map_err(adjust_wast)?;
let ast = wast::parser::parse::<wast::Wast>(&buf).map_err(adjust_wast)?;
for directive in ast.directives {
let sp = directive.span();
self.run_directive(directive, &adjust_wast)
.with_context(|| {
let (line, col) = sp.linecol_in(wast);
format!("failed directive on {}:{}:{}", filename, line + 1, col)
})?;
}
Ok(())
}
fn run_directive(
&mut self,
directive: wast::WastDirective,
adjust: impl Fn(wast::Error) -> wast::Error,
) -> Result<()> {
use wast::WastDirective::*;
match directive {
Module(mut module) => {
let binary = module.encode().map_err(adjust)?;
self.module(module.id.map(|s| s.name()), &binary)?;
}
QuoteModule { span: _, source } => {
let mut module = String::new();
for src in source {
module.push_str(str::from_utf8(src)?);
module.push_str(" ");
}
let buf = ParseBuffer::new(&module)?;
let mut wat = parser::parse::<Wat>(&buf).map_err(|mut e| {
e.set_text(&module);
e
})?;
let binary = wat.module.encode()?;
self.module(wat.module.id.map(|s| s.name()), &binary)?;
}
Register {
span: _,
name,
module,
} => {
self.register(module.map(|s| s.name()), name)?;
}
Invoke(i) => {
self.perform_invoke(i)?;
}
AssertReturn {
span: _,
exec,
results,
} => {
let result = self.perform_execute(exec)?;
self.assert_return(result, &results)?;
}
AssertTrap {
span: _,
exec,
message,
} => {
let result = self.perform_execute(exec)?;
self.assert_trap(result, message)?;
}
AssertExhaustion {
span: _,
call,
message,
} => {
let result = self.perform_invoke(call)?;
self.assert_trap(result, message)?;
}
AssertInvalid {
span: _,
mut module,
message,
} => {
let bytes = module.encode()?;
let err = match self.module(None, &bytes) {
Ok(()) => bail!("expected module to fail to build"),
Err(e) => e,
};
let error_message = format!("{:?}", err);
if !is_matching_assert_invalid_error_message(&message, &error_message) {
bail!(
"assert_invalid: expected \"{}\", got \"{}\"",
message,
error_message
)
}
}
AssertMalformed {
module,
span: _,
message: _,
} => {
let mut module = match module {
wast::QuoteModule::Module(m) => m,
// This is a `*.wat` parser test which we're not
// interested in.
wast::QuoteModule::Quote(_) => return Ok(()),
};
let bytes = module.encode().map_err(adjust)?;
if let Ok(_) = self.module(None, &bytes) {
bail!("expected malformed module to fail to instantiate");
}
}
AssertUnlinkable {
span: _,
mut module,
message,
} => {
let bytes = module.encode().map_err(adjust)?;
let err = match self.module(None, &bytes) {
Ok(()) => bail!("expected module to fail to link"),
Err(e) => e,
};
let error_message = format!("{:?}", err);
if !error_message.contains(&message) {
bail!(
"assert_unlinkable: expected {}, got {}",
message,
error_message
)
}
}
}
Ok(())
}
/// Run a wast script from a file.
pub fn run_file(&mut self, path: &Path) -> Result<()> {
let bytes =
std::fs::read(path).with_context(|| format!("failed to read `{}`", path.display()))?;
self.run_buffer(path.to_str().unwrap(), &bytes)
}
}
fn is_matching_assert_invalid_error_message(expected: &str, actual: &str) -> bool {
actual.contains(expected)
// `elem.wast` and `proposals/bulk-memory-operations/elem.wast` disagree
// on the expected error message for the same error.
|| (expected.contains("out of bounds") && actual.contains("does not fit"))
// slight difference in error messages
|| (expected.contains("unknown elem segment") && actual.contains("unknown element segment"))
}
fn extract_lane_as_i8(bytes: u128, lane: usize) -> i8 {
(bytes >> (lane * 8)) as i8
}
fn extract_lane_as_i16(bytes: u128, lane: usize) -> i16 {
(bytes >> (lane * 16)) as i16
}
fn extract_lane_as_i32(bytes: u128, lane: usize) -> i32 {
(bytes >> (lane * 32)) as i32
}
fn extract_lane_as_i64(bytes: u128, lane: usize) -> i64 {
(bytes >> (lane * 64)) as i64
}
/// Check if an f32 (as u32 bits to avoid possible quieting when moving values in registers, e.g.
/// https://developer.arm.com/documentation/ddi0344/i/neon-and-vfp-programmers-model/modes-of-operation/default-nan-mode?lang=en)
/// is a canonical NaN:
/// - the sign bit is unspecified,
/// - the 8-bit exponent is set to all 1s
/// - the MSB of the payload is set to 1 (a quieted NaN) and all others to 0.
/// See https://webassembly.github.io/spec/core/syntax/values.html#floating-point.
fn is_canonical_f32_nan(bits: u32) -> bool {
(bits & 0x7fff_ffff) == 0x7fc0_0000
}
/// Check if an f64 (as u64 bits to avoid possible quieting when moving values in registers, e.g.
/// https://developer.arm.com/documentation/ddi0344/i/neon-and-vfp-programmers-model/modes-of-operation/default-nan-mode?lang=en)
/// is a canonical NaN:
/// - the sign bit is unspecified,
/// - the 11-bit exponent is set to all 1s
/// - the MSB of the payload is set to 1 (a quieted NaN) and all others to 0.
/// See https://webassembly.github.io/spec/core/syntax/values.html#floating-point.
fn is_canonical_f64_nan(bits: u64) -> bool {
(bits & 0x7fff_ffff_ffff_ffff) == 0x7ff8_0000_0000_0000
}
/// Check if an f32 (as u32, see comments above) is an arithmetic NaN. This is the same as a
/// canonical NaN including that the payload MSB is set to 1, but one or more of the remaining
/// payload bits MAY BE set to 1 (a canonical NaN specifies all 0s). See
/// https://webassembly.github.io/spec/core/syntax/values.html#floating-point.
fn is_arithmetic_f32_nan(bits: u32) -> bool {
const AF32_NAN: u32 = 0x7f80_0000;
let is_nan = bits & AF32_NAN == AF32_NAN;
const AF32_PAYLOAD_MSB: u32 = 0x0040_0000;
let is_msb_set = bits & AF32_PAYLOAD_MSB == AF32_PAYLOAD_MSB;
is_nan && is_msb_set
}
/// Check if an f64 (as u64, see comments above) is an arithmetic NaN. This is the same as a
/// canonical NaN including that the payload MSB is set to 1, but one or more of the remaining
/// payload bits MAY BE set to 1 (a canonical NaN specifies all 0s). See
/// https://webassembly.github.io/spec/core/syntax/values.html#floating-point.
fn is_arithmetic_f64_nan(bits: u64) -> bool {
const AF64_NAN: u64 = 0x7ff0_0000_0000_0000;
let is_nan = bits & AF64_NAN == AF64_NAN;
const AF64_PAYLOAD_MSB: u64 = 0x0008_0000_0000_0000;
let is_msb_set = bits & AF64_PAYLOAD_MSB == AF64_PAYLOAD_MSB;
is_nan && is_msb_set
}
fn val_matches(actual: &Val, expected: &wast::AssertExpression) -> Result<bool> {
Ok(match (actual, expected) {
(Val::I32(a), wast::AssertExpression::I32(b)) => a == b,
(Val::I64(a), wast::AssertExpression::I64(b)) => a == b,
// Note that these float comparisons are comparing bits, not float
// values, so we're testing for bit-for-bit equivalence
(Val::F32(a), wast::AssertExpression::F32(b)) => f32_matches(*a, b),
(Val::F64(a), wast::AssertExpression::F64(b)) => f64_matches(*a, b),
(Val::V128(a), wast::AssertExpression::V128(b)) => v128_matches(*a, b),
(Val::ExternRef(x), wast::AssertExpression::RefNull(Some(HeapType::Extern))) => x.is_none(),
(Val::ExternRef(x), wast::AssertExpression::RefExtern(y)) => {
if let Some(x) = x {
let x = x
.data()
.downcast_ref::<u32>()
.expect("only u32 externrefs created in wast test suites");
x == y
} else {
false
}
}
(Val::FuncRef(x), wast::AssertExpression::RefNull(_)) => x.is_none(),
_ => bail!(
"don't know how to compare {:?} and {:?} yet",
actual,
expected
),
})
}
fn f32_matches(actual: u32, expected: &wast::NanPattern<wast::Float32>) -> bool {
match expected {
wast::NanPattern::CanonicalNan => is_canonical_f32_nan(actual),
wast::NanPattern::ArithmeticNan => is_arithmetic_f32_nan(actual),
wast::NanPattern::Value(expected_value) => actual == expected_value.bits,
}
}
fn f64_matches(actual: u64, expected: &wast::NanPattern<wast::Float64>) -> bool {
match expected {
wast::NanPattern::CanonicalNan => is_canonical_f64_nan(actual),
wast::NanPattern::ArithmeticNan => is_arithmetic_f64_nan(actual),
wast::NanPattern::Value(expected_value) => actual == expected_value.bits,
}
}
fn v128_matches(actual: u128, expected: &wast::V128Pattern) -> bool {
match expected {
wast::V128Pattern::I8x16(b) => b
.iter()
.enumerate()
.all(|(i, b)| *b == extract_lane_as_i8(actual, i)),
wast::V128Pattern::I16x8(b) => b
.iter()
.enumerate()
.all(|(i, b)| *b == extract_lane_as_i16(actual, i)),
wast::V128Pattern::I32x4(b) => b
.iter()
.enumerate()
.all(|(i, b)| *b == extract_lane_as_i32(actual, i)),
wast::V128Pattern::I64x2(b) => b
.iter()
.enumerate()
.all(|(i, b)| *b == extract_lane_as_i64(actual, i)),
wast::V128Pattern::F32x4(b) => b.iter().enumerate().all(|(i, b)| {
let a = extract_lane_as_i32(actual, i) as u32;
f32_matches(a, b)
}),
wast::V128Pattern::F64x2(b) => b.iter().enumerate().all(|(i, b)| {
let a = extract_lane_as_i64(actual, i) as u64;
f64_matches(a, b)
}),
}
}
/// When troubleshooting a failure in a spec test, it is valuable to understand the bit-by-bit
/// difference. To do this, we print a hex-encoded version of Wasm values and assertion expressions
/// using this helper.
fn as_hex_pattern<T>(bits: T) -> String
where
T: fmt::LowerHex,
{
format!("{1:#00$x}", size_of_val(&bits) * 2 + 2, bits)
}
/// The [AsHexPattern] allows us to extend `as_hex_pattern` to various structures.
trait AsHexPattern {
fn as_hex_pattern(&self) -> String;
}
impl AsHexPattern for wast::AssertExpression<'_> {
fn as_hex_pattern(&self) -> String {
match self {
wast::AssertExpression::I32(i) => as_hex_pattern(*i),
wast::AssertExpression::I64(i) => as_hex_pattern(*i),
wast::AssertExpression::F32(f) => f.as_hex_pattern(),
wast::AssertExpression::F64(f) => f.as_hex_pattern(),
wast::AssertExpression::V128(v) => v.as_hex_pattern(),
wast::AssertExpression::RefNull(_)
| wast::AssertExpression::RefExtern(_)
| wast::AssertExpression::RefFunc(_)
| wast::AssertExpression::LegacyArithmeticNaN
| wast::AssertExpression::LegacyCanonicalNaN => "no hex representation".to_string(),
}
}
}
impl AsHexPattern for wast::NanPattern<wast::Float32> {
fn as_hex_pattern(&self) -> String {
match self {
wast::NanPattern::CanonicalNan => "0x7fc00000".to_string(),
// Note that NaN patterns can have varying sign bits and payloads. Technically the first
// bit should be a `*` but it is impossible to show that in hex.
wast::NanPattern::ArithmeticNan => "0x7fc*****".to_string(),
wast::NanPattern::Value(wast::Float32 { bits }) => as_hex_pattern(*bits),
}
}
}
impl AsHexPattern for wast::NanPattern<wast::Float64> {
fn as_hex_pattern(&self) -> String {
match self {
wast::NanPattern::CanonicalNan => "0x7ff8000000000000".to_string(),
// Note that NaN patterns can have varying sign bits and payloads. Technically the first
// bit should be a `*` but it is impossible to show that in hex.
wast::NanPattern::ArithmeticNan => "0x7ff8************".to_string(),
wast::NanPattern::Value(wast::Float64 { bits }) => as_hex_pattern(*bits),
}
}
}
// This implementation reverses both the lanes and the lane bytes in order to match the Wasm SIMD
// little-endian order. This implementation must include special behavior for this reversal; other
// implementations do not because they deal with raw values (`u128`) or use big-endian order for
// display (scalars).
impl AsHexPattern for wast::V128Pattern {
fn as_hex_pattern(&self) -> String {
fn reverse_pattern(pattern: String) -> String {
let chars: Vec<char> = pattern[2..].chars().collect();
let reversed: Vec<&[char]> = chars.chunks(2).rev().collect();
reversed.concat().iter().collect()
}
fn as_hex_pattern(bits: &[u8]) -> String {
bits.iter()
.map(|b| format!("{:02x}", b))
.collect::<Vec<_>>()
.concat()
}
fn reverse_lanes<T, F>(
lanes: impl DoubleEndedIterator<Item = T>,
as_hex_pattern: F,
) -> String
where
F: Fn(T) -> String,
{
lanes
.rev()
.map(|f| as_hex_pattern(f))
.collect::<Vec<_>>()
.concat()
}
let lanes_as_hex = match self {
wast::V128Pattern::I8x16(v) => {
reverse_lanes(v.iter(), |b| as_hex_pattern(&b.to_le_bytes()))
}
wast::V128Pattern::I16x8(v) => {
reverse_lanes(v.iter(), |b| as_hex_pattern(&b.to_le_bytes()))
}
wast::V128Pattern::I32x4(v) => {
reverse_lanes(v.iter(), |b| as_hex_pattern(&b.to_le_bytes()))
}
wast::V128Pattern::I64x2(v) => {
reverse_lanes(v.iter(), |b| as_hex_pattern(&b.to_le_bytes()))
}
wast::V128Pattern::F32x4(v) => {
reverse_lanes(v.iter(), |b| reverse_pattern(b.as_hex_pattern()))
}
wast::V128Pattern::F64x2(v) => {
reverse_lanes(v.iter(), |b| reverse_pattern(b.as_hex_pattern()))
}
};
String::from("0x") + &lanes_as_hex
}
}
impl AsHexPattern for Val {
fn as_hex_pattern(&self) -> String {
match self {
Val::I32(i) => as_hex_pattern(*i),
Val::I64(i) => as_hex_pattern(*i),
Val::F32(f) => as_hex_pattern(*f),
Val::F64(f) => as_hex_pattern(*f),
Val::V128(v) => as_hex_pattern(*v),
Val::ExternRef(_) | Val::FuncRef(_) => "no hex representation".to_string(),
}
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn val_to_hex() {
assert_eq!(Val::I32(0x42).as_hex_pattern(), "0x00000042");
assert_eq!(Val::F64(0x0).as_hex_pattern(), "0x0000000000000000");
assert_eq!(
Val::V128(u128::from_le_bytes([
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf
]))
.as_hex_pattern(),
"0x0f0e0d0c0b0a09080706050403020100"
);
}
#[test]
fn assert_expression_to_hex() {
assert_eq!(
wast::AssertExpression::F32(wast::NanPattern::ArithmeticNan).as_hex_pattern(),
"0x7fc*****"
);
assert_eq!(
wast::AssertExpression::F64(wast::NanPattern::Value(wast::Float64 { bits: 0x42 }))
.as_hex_pattern(),
"0x0000000000000042"
);
assert_eq!(
wast::AssertExpression::V128(wast::V128Pattern::I32x4([0, 1, 2, 3])).as_hex_pattern(),
"0x03000000020000000100000000000000"
);
assert_eq!(
wast::AssertExpression::V128(wast::V128Pattern::F64x2([
wast::NanPattern::CanonicalNan,
wast::NanPattern::ArithmeticNan
]))
.as_hex_pattern(),
"0x************f87f000000000000f87f"
);
}
}