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* Move `Module::compile` to `Engine::precompile_module`.
* Remove `Module::deserialize` method.
* Make `Module::serialize` the same format as `Engine::precompile_module`.
* Make `Engine::precompile_module` return a `Vec<u8>`.
* Move the remaining serialization-related code to `serialization.rs`.
This commit is contained in:
Peter Huene
2021-03-31 23:46:30 -07:00
parent abf3bf29f9
commit d1313b1291
10 changed files with 136 additions and 146 deletions
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15
RELEASES.md
View File

@@ -6,14 +6,13 @@
### Added
* The `wasmtime compile` command was added to support AOT compilation of Wasm
modules.
* Added the `wasmtime compile` command to support AOT compilation of Wasm modules.
* The `Module::compile` method was added to support AOT compilation of a module.
* Added the `Engine::precompile_module` method to support AOT module compilation.
* Added the `Config::target` method to change the compilation target of the
configuration. This can be used in conjunction with `Module::compile` to target
a different host triple than the current one.
configuration. This can be used in conjunction with `Engine::precompile_module`
to target a different host triple than the current one.
* Added the `Config::cranelift_flag_enable` method to enable setting Cranelift
boolean flags or presets in a config.
@@ -26,6 +25,8 @@
singular `--wasm-features` option. The previous options are still supported, but
are not displayed in help text.
* Breaking: `Module::deserialize` has been removed in favor of `Module::new`.
* Breaking: `Config::cranelift_clear_cpu_flags` was removed. Use `Config::target`
to clear the CPU flags for the host's target.
@@ -42,10 +43,6 @@
* Breaking: the CLI option `--enable-bulk-memory=false` has been changed to
`--wasm-features=-bulk-memory`.
* Modules serialized with `Module::serialize` can now be deserialized with
`Module::deserialize` on a compatible host that does not have to match the
original environment exactly.
## 0.25.0
Released 2021-03-16.

11
crates/c-api/src/module.rs
View File

@@ -185,13 +185,10 @@ pub extern "C" fn wasmtime_module_deserialize(
binary: &wasm_byte_vec_t,
ret: &mut *mut wasm_module_t,
) -> Option<Box<wasmtime_error_t>> {
handle_result(
Module::deserialize(&engine.engine, binary.as_slice()),
|module| {
let module = Box::new(wasm_module_t::new(module));
*ret = Box::into_raw(module);
},
)
handle_result(Module::new(&engine.engine, binary.as_slice()), |module| {
let module = Box::new(wasm_module_t::new(module));
*ret = Box::into_raw(module);
})
}
#[no_mangle]

28
crates/wasmtime/src/engine.rs
View File

@@ -78,6 +78,34 @@ impl Engine {
pub fn same(a: &Engine, b: &Engine) -> bool {
Arc::ptr_eq(&a.inner, &b.inner)
}
/// Ahead-of-time (AOT) compiles a WebAssembly module.
///
/// The `bytes` provided must be in one of two formats:
///
/// * A [binary-encoded][binary] WebAssembly module. This is always supported.
/// * A [text-encoded][text] instance of the WebAssembly text format.
/// This is only supported when the `wat` feature of this crate is enabled.
/// If this is supplied then the text format will be parsed before validation.
/// Note that the `wat` feature is enabled by default.
///
/// [binary]: https://webassembly.github.io/spec/core/binary/index.html
/// [text]: https://webassembly.github.io/spec/core/text/index.html
pub fn precompile_module(&self, bytes: &[u8]) -> Result<Vec<u8>> {
const USE_PAGED_MEM_INIT: bool = cfg!(all(feature = "uffd", target_os = "linux"));
#[cfg(feature = "wat")]
let bytes = wat::parse_bytes(&bytes)?;
let (_, artifacts, types) = wasmtime_jit::CompilationArtifacts::build(
&self.inner.compiler,
&bytes,
USE_PAGED_MEM_INIT,
)?;
crate::module::SerializedModule::from_artifacts(&self.inner.compiler, &artifacts, &types)
.to_bytes()
}
}
impl Default for Engine {

123
crates/wasmtime/src/module.rs
View File

@@ -1,9 +1,7 @@
use crate::types::{ExportType, ExternType, ImportType};
use crate::{Engine, ModuleType};
use anyhow::{bail, Context, Result};
use bincode::Options;
use std::fs;
use std::io::Write;
use std::path::Path;
use std::sync::Arc;
use wasmparser::Validator;
@@ -15,9 +13,7 @@ use wasmtime_jit::{CompilationArtifacts, CompiledModule, TypeTables};
mod serialization;
use serialization::SerializedModule;
const COMPILED_MODULE_HEADER: &[u8] = b"\0wasmtime-aot";
pub use serialization::SerializedModule;
/// A compiled WebAssembly module, ready to be instantiated.
///
@@ -111,14 +107,16 @@ struct ModuleInner {
impl Module {
/// Creates a new WebAssembly `Module` from the given in-memory `bytes`.
///
/// The `bytes` provided must be in one of three formats:
/// The `bytes` provided must be in one of the following formats:
///
/// * A [binary-encoded][binary] WebAssembly module. This is always supported.
/// * A [text-encoded][text] instance of the WebAssembly text format.
/// This is only supported when the `wat` feature of this crate is enabled.
/// If this is supplied then the text format will be parsed before validation.
/// Note that the `wat` feature is enabled by default.
/// * A module compiled with [`Module::compile`] or the `wasmtime compile` command.
/// * A module serialized with [`Module::serialize`].
/// * A module compiled with [`Engine::precompile_module`] or the
/// `wasmtime compile` command.
///
/// The data for the wasm module must be loaded in-memory if it's present
/// elsewhere, for example on disk. This requires that the entire binary is
@@ -177,8 +175,9 @@ impl Module {
/// ```
pub fn new(engine: &Engine, bytes: impl AsRef<[u8]>) -> Result<Module> {
let bytes = bytes.as_ref();
if bytes.starts_with(COMPILED_MODULE_HEADER) {
return Self::deserialize(engine, &bytes[COMPILED_MODULE_HEADER.len()..]);
if let Some(module) = SerializedModule::from_bytes(bytes)? {
return module.into_module(engine);
}
#[cfg(feature = "wat")]
@@ -267,8 +266,8 @@ impl Module {
/// # }
/// ```
pub fn from_binary(engine: &Engine, binary: &[u8]) -> Result<Module> {
if binary.starts_with(COMPILED_MODULE_HEADER) {
return Self::deserialize(engine, &binary[COMPILED_MODULE_HEADER.len()..]);
if let Some(module) = SerializedModule::from_bytes(binary)? {
return module.into_module(engine);
}
// Check to see that the config's target matches the host
@@ -344,41 +343,6 @@ impl Module {
Ok(())
}
/// Ahead-of-time (AOT) compiles a WebAssembly module.
///
/// The `bytes` provided must be in one of two formats:
///
/// * A [binary-encoded][binary] WebAssembly module. This is always supported.
/// * A [text-encoded][text] instance of the WebAssembly text format.
/// This is only supported when the `wat` feature of this crate is enabled.
/// If this is supplied then the text format will be parsed before validation.
/// Note that the `wat` feature is enabled by default.
///
/// See [`Module::new`] for errors that may be returned by this function.
///
/// [binary]: https://webassembly.github.io/spec/core/binary/index.html
/// [text]: https://webassembly.github.io/spec/core/text/index.html
pub fn compile(engine: &Engine, bytes: &[u8], mut output: impl Write) -> Result<()> {
const USE_PAGED_MEM_INIT: bool = cfg!(all(feature = "uffd", target_os = "linux"));
if bytes.starts_with(COMPILED_MODULE_HEADER) {
bail!("input is already a compiled module");
}
#[cfg(feature = "wat")]
let bytes = wat::parse_bytes(&bytes)?;
let (_, artifacts, types) =
CompilationArtifacts::build(engine.compiler(), &bytes, USE_PAGED_MEM_INIT)?;
// Write a header that marks this as a compiled module
output.write_all(COMPILED_MODULE_HEADER)?;
Self::serialize_module(
&SerializedModule::from_artifacts(engine.compiler(), &artifacts, &types),
output,
)
}
/// Returns the type signature of this module.
pub fn ty(&self) -> ModuleType {
let mut sig = ModuleType::new();
@@ -396,58 +360,12 @@ impl Module {
sig
}
/// Serialize compilation artifacts to the buffer. See also `deserialize`.
pub fn serialize(&self) -> Result<Vec<u8>> {
let mut buffer = Vec::new();
Self::serialize_module(&SerializedModule::new(self), &mut buffer)?;
Ok(buffer)
}
fn serialize_module(module: &SerializedModule, mut output: impl Write) -> Result<()> {
// Preface the data with a version so we can do a version check independent
// of the serialized data.
let version = env!("CARGO_PKG_VERSION");
assert!(
version.len() < 256,
"package version must be less than 256 bytes"
);
output.write(&[version.len() as u8])?;
output.write_all(version.as_bytes())?;
bincode_options().serialize_into(output, module)?;
Ok(())
}
/// Deserializes and creates a module from the compilation artifacts.
/// The `serialize` saves the compilation artifacts along with the host
/// fingerprint, which consists of target, compiler flags, and wasmtime
/// package version.
/// Serialize the module to a vector of bytes.
///
/// The method will fail if fingerprints of current host and serialized
/// one are different. The method does not verify the serialized artifacts
/// for modifications or corruptions. All responsibly of signing and its
/// verification falls on the embedder.
pub fn deserialize(engine: &Engine, serialized: &[u8]) -> Result<Module> {
if serialized.is_empty() {
bail!("serialized data data is empty");
}
let version_len = serialized[0] as usize;
if serialized.len() < version_len + 1 {
bail!("serialized data is malformed");
}
let version = std::str::from_utf8(&serialized[1..1 + version_len])?;
if version != env!("CARGO_PKG_VERSION") {
bail!(
"Module was compiled with incompatible Wasmtime version '{}'",
version
);
}
bincode_options()
.deserialize::<SerializedModule<'_>>(&serialized[1 + version_len..])
.context("Deserialize compilation artifacts")?
.into_module(engine)
/// Use `Module::new` or `Module::from_binary` to create the module
/// from the bytes.
pub fn serialize(&self) -> Result<Vec<u8>> {
SerializedModule::new(self).to_bytes()
}
/// Creates a submodule `Module` value from the specified parameters.
@@ -732,17 +650,6 @@ impl Module {
}
}
fn bincode_options() -> impl Options {
// Use a variable-length integer encoding instead of fixed length. The
// module shown on #2318 gets compressed from ~160MB to ~110MB simply using
// this, presumably because there's a lot of 8-byte integers which generally
// have small values. Local testing shows that the deserialization
// performance, while higher, is in the few-percent range. For huge size
// savings this seems worthwhile to lose a small percentage of
// deserialization performance.
bincode::DefaultOptions::new().with_varint_encoding()
}
fn _assert_send_sync() {
fn _assert<T: Send + Sync>() {}
_assert::<Module>();

70
crates/wasmtime/src/module/serialization.rs
View File

@@ -2,7 +2,8 @@
use super::ModuleInner;
use crate::{Engine, Module, OptLevel};
use anyhow::{anyhow, bail, Result};
use anyhow::{anyhow, bail, Context, Result};
use bincode::Options;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::hash::{Hash, Hasher};
@@ -14,6 +15,19 @@ use wasmtime_jit::{
CompilationArtifacts, CompilationStrategy, CompiledModule, Compiler, TypeTables,
};
const HEADER: &[u8] = b"\0wasmtime-aot";
fn bincode_options() -> impl Options {
// Use a variable-length integer encoding instead of fixed length. The
// module shown on #2318 gets compressed from ~160MB to ~110MB simply using
// this, presumably because there's a lot of 8-byte integers which generally
// have small values. Local testing shows that the deserialization
// performance, while higher, is in the few-percent range. For huge size
// savings this seems worthwhile to lose a small percentage of
// deserialization performance.
bincode::DefaultOptions::new().with_varint_encoding()
}
// This exists because `wasmparser::WasmFeatures` isn't serializable
#[derive(Hash, Debug, Copy, Clone, Serialize, Deserialize)]
struct WasmFeatures {
@@ -273,6 +287,60 @@ impl<'a> SerializedModule<'a> {
}
}
pub fn to_bytes(&self) -> Result<Vec<u8>> {
use std::io::Write;
let mut bytes = Vec::new();
bytes.write_all(HEADER)?;
// Preface the data with a version so we can do a version check independent
// of the serialized data.
let version = env!("CARGO_PKG_VERSION");
assert!(
version.len() < 256,
"package version must be less than 256 bytes"
);
bytes.write(&[version.len() as u8])?;
bytes.write_all(version.as_bytes())?;
bincode_options().serialize_into(&mut bytes, self)?;
Ok(bytes)
}
pub fn from_bytes(bytes: &[u8]) -> Result<Option<Self>> {
if !bytes.starts_with(HEADER) {
return Ok(None);
}
let bytes = &bytes[HEADER.len()..];
if bytes.is_empty() {
bail!("serialized data data is empty");
}
let version_len = bytes[0] as usize;
if bytes.len() < version_len + 1 {
bail!("serialized data is malformed");
}
let version = std::str::from_utf8(&bytes[1..1 + version_len])?;
if version != env!("CARGO_PKG_VERSION") {
bail!(
"Module was compiled with incompatible Wasmtime version '{}'",
version
);
}
Ok(Some(
bincode_options()
.deserialize::<SerializedModule<'_>>(&bytes[1 + version_len..])
.context("deserialize compilation artifacts")?,
))
}
fn check_triple(&self, isa: &dyn TargetIsa) -> Result<()> {
let triple = target_lexicon::Triple::from_str(&self.target).map_err(|e| anyhow!(e))?;

2
examples/serialize.rs
View File

@@ -31,7 +31,7 @@ fn deserialize(buffer: &[u8]) -> Result<()> {
// Compile the wasm binary into an in-memory instance of a `Module`.
println!("Deserialize module...");
let module = Module::deserialize(store.engine(), buffer)?;
let module = Module::new(store.engine(), buffer)?;
// Here we handle the imports of the module, which in this case is our
// `HelloCallback` type and its associated implementation of `Callback.

10
src/commands/compile.rs
View File

@@ -2,15 +2,14 @@
use crate::CommonOptions;
use anyhow::{bail, Context, Result};
use std::fs::{self, File};
use std::io::BufWriter;
use std::fs;
use std::path::PathBuf;
use structopt::{
clap::{AppSettings, ArgGroup},
StructOpt,
};
use target_lexicon::Triple;
use wasmtime::{Engine, Module};
use wasmtime::Engine;
lazy_static::lazy_static! {
static ref AFTER_HELP: String = {
@@ -100,8 +99,7 @@ impl CompileCommand {
output
});
let mut writer = BufWriter::new(File::create(&output)?);
Module::compile(&engine, &input, &mut writer)?;
fs::write(output, engine.precompile_module(&input)?)?;
Ok(())
}
@@ -112,7 +110,7 @@ mod test {
use super::*;
use std::io::Write;
use tempfile::NamedTempFile;
use wasmtime::{Instance, Store};
use wasmtime::{Instance, Module, Store};
#[test]
fn test_successful_compile() -> Result<()> {

15
tests/all/module.rs
View File

@@ -1,5 +1,4 @@
use anyhow::Result;
use std::io::BufWriter;
use wasmtime::*;
#[test]
@@ -28,18 +27,18 @@ fn caches_across_engines() {
.serialize()
.unwrap();
let res = Module::deserialize(&Engine::new(&Config::new()).unwrap(), &bytes);
let res = Module::new(&Engine::new(&Config::new()).unwrap(), &bytes);
assert!(res.is_ok());
// differ in shared cranelift flags
let res = Module::deserialize(
let res = Module::new(
&Engine::new(Config::new().cranelift_nan_canonicalization(true)).unwrap(),
&bytes,
);
assert!(res.is_err());
// differ in cranelift settings
let res = Module::deserialize(
let res = Module::new(
&Engine::new(Config::new().cranelift_opt_level(OptLevel::None)).unwrap(),
&bytes,
);
@@ -47,7 +46,7 @@ fn caches_across_engines() {
// Missing required cpu flags
if cfg!(target_arch = "x86_64") {
let res = Module::deserialize(
let res = Module::new(
&Engine::new(
Config::new()
.target(&target_lexicon::Triple::host().to_string())
@@ -63,14 +62,10 @@ fn caches_across_engines() {
#[test]
fn aot_compiles() -> Result<()> {
let engine = Engine::default();
let mut writer = BufWriter::new(Vec::new());
Module::compile(
&engine,
let bytes = engine.precompile_module(
"(module (func (export \"f\") (param i32) (result i32) local.get 0))".as_bytes(),
&mut writer,
)?;
let bytes = writer.into_inner()?;
let module = Module::from_binary(&engine, &bytes)?;
let store = Store::new(&engine);

2
tests/all/module_linking.rs
View File

@@ -39,7 +39,7 @@ fn compile() -> Result<()> {
assert_eq!(m.imports().len(), 0);
assert_eq!(m.exports().len(), 0);
let bytes = m.serialize()?;
Module::deserialize(&engine, &bytes)?;
Module::new(&engine, &bytes)?;
assert_eq!(m.imports().len(), 0);
assert_eq!(m.exports().len(), 0);
Ok(())

6
tests/all/module_serialize.rs
View File

@@ -7,7 +7,7 @@ fn serialize(engine: &Engine, wat: &'static str) -> Result<Vec<u8>> {
}
fn deserialize_and_instantiate(store: &Store, buffer: &[u8]) -> Result<Instance> {
let module = Module::deserialize(store.engine(), buffer)?;
let module = Module::new(store.engine(), buffer)?;
Ok(Instance::new(&store, &module, &[])?)
}
@@ -15,9 +15,9 @@ fn deserialize_and_instantiate(store: &Store, buffer: &[u8]) -> Result<Instance>
fn test_version_mismatch() -> Result<()> {
let engine = Engine::default();
let mut buffer = serialize(&engine, "(module)")?;
buffer[1] = 'x' as u8;
buffer[13 /* header length */ + 1 /* version length */] = 'x' as u8;
match Module::deserialize(&engine, &buffer) {
match Module::new(&engine, &buffer) {
Ok(_) => bail!("expected deserialization to fail"),
Err(e) => assert_eq!(
e.to_string(),