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#[cfg(feature = "component-model")]
use crate::component::Component;
use crate::prelude::*;
use crate::runtime::vm::MmapVec;
use crate::{CodeBuilder, CodeMemory, Engine, Module};
use object::write::WritableBuffer;
use std::sync::Arc;
use wasmtime_environ::{FinishedObject, ObjectBuilder};
impl<'a> CodeBuilder<'a> {
fn compile_cached<T, S>(
&self,
build_artifacts: fn(
&Engine,
&[u8],
Option<&[u8]>,
Option<&str>,
&S,
) -> Result<(MmapVecWrapper, Option<T>)>,
state: &S,
) -> Result<(Arc<CodeMemory>, Option<T>)> {
let wasm = self.get_wasm()?;
let dwarf_package = self.get_dwarf_package();
let unsafe_intrinsics_import = self.get_unsafe_intrinsics_import();
self.engine
.check_compatible_with_native_host()
.context("compilation settings are not compatible with the native host")?;
#[cfg(feature = "cache")]
{
let state = (
crate::compile::HashedEngineCompileEnv(self.engine),
&wasm,
&dwarf_package,
&unsafe_intrinsics_import,
// Don't hash this as it's just its own "pure" function pointer.
NotHashed(build_artifacts),
// Don't hash the FinishedObject state: this contains
// things like required runtime alignment, and does
// not impact the compilation result itself.
NotHashed(state),
);
let (code, info_and_types) =
wasmtime_cache::ModuleCacheEntry::new("wasmtime", self.engine.cache())
.get_data_raw(
&state,
// Cache miss, compute the actual artifacts
|(
engine,
wasm,
dwarf_package,
unsafe_intrinsics_import,
build_artifacts,
state,
)|
-> Result<_> {
let (mmap, info) = (build_artifacts.0)(
engine.0,
wasm,
dwarf_package.as_deref(),
**unsafe_intrinsics_import,
state.0,
)?;
let code = publish_mmap(engine.0, mmap.0)?;
Ok((code, info))
},
// Implementation of how to serialize artifacts
|(_engine, _wasm, _, _, _, _), (code, _info_and_types)| {
Some(code.mmap().to_vec())
},
// Cache hit, deserialize the provided artifacts
|(engine, wasm, _, _, _, _), serialized_bytes| {
let kind = if wasmparser::Parser::is_component(&wasm) {
wasmtime_environ::ObjectKind::Component
} else {
wasmtime_environ::ObjectKind::Module
};
let code = engine.0.load_code_bytes(&serialized_bytes, kind).ok()?;
Some((code, None))
},
)?;
return Ok((code, info_and_types));
struct NotHashed<T>(T);
impl<T> std::hash::Hash for NotHashed<T> {
fn hash<H: std::hash::Hasher>(&self, _hasher: &mut H) {}
}
}
#[cfg(not(feature = "cache"))]
{
let (mmap, info_and_types) = build_artifacts(
self.engine,
&wasm,
dwarf_package.as_deref(),
unsafe_intrinsics_import,
state,
)?;
let code = publish_mmap(self.engine, mmap.0)?;
return Ok((code, info_and_types));
}
}
/// Same as [`CodeBuilder::compile_module_serialized`] except that a
/// [`Module`](crate::Module) is produced instead.
///
/// Note that this method will cache compilations if the `cache` feature is
/// enabled and turned on in [`Config`](crate::Config).
pub fn compile_module(&self) -> Result<Module> {
ensure!(
self.get_unsafe_intrinsics_import().is_none(),
"`CodeBuilder::expose_unsafe_intrinsics` can only be used with components"
);
#[cfg(feature = "compile-time-builtins")]
ensure!(
self.get_compile_time_builtins().is_empty(),
"compile-time builtins can only be used with components"
);
let custom_alignment = self.custom_alignment();
let (code, info_and_types) = self.compile_cached(
|engine, wasm, dwarf, unsafe_intrinsics_import, state| {
assert!(unsafe_intrinsics_import.is_none());
super::build_module_artifacts(engine, wasm, dwarf, state)
},
&custom_alignment,
)?;
Module::from_parts(self.engine, code, info_and_types)
}
/// Same as [`CodeBuilder::compile_module`] except that it compiles a
/// [`Component`] instead of a module.
#[cfg(feature = "component-model")]
pub fn compile_component(&self) -> Result<Component> {
let custom_alignment = self.custom_alignment();
let (code, artifacts) = self.compile_cached(
|engine, wasm, dwarf, unsafe_intrinsics_import, state| {
super::build_component_artifacts(
engine,
wasm,
dwarf,
unsafe_intrinsics_import,
state,
)
},
&custom_alignment,
)?;
Component::from_parts(self.engine, code, artifacts)
}
fn custom_alignment(&self) -> CustomAlignment {
CustomAlignment {
alignment: self
.engine
.custom_code_memory()
.map(|c| c.required_alignment())
.unwrap_or(1),
}
}
}
fn publish_mmap(engine: &Engine, mmap: MmapVec) -> Result<Arc<CodeMemory>> {
let mut code = CodeMemory::new(engine, mmap)?;
code.publish()?;
Ok(Arc::new(code))
}
pub(crate) struct MmapVecWrapper(pub MmapVec);
/// Custom alignment requirements from the Engine for
/// produced-at-runtime-in-memory code artifacts.
pub(crate) struct CustomAlignment {
alignment: usize,
}
impl FinishedObject for MmapVecWrapper {
type State = CustomAlignment;
fn finish_object(obj: ObjectBuilder<'_>, align: &CustomAlignment) -> Result<Self> {
let mut result = ObjectMmap::default();
result.alignment = align.alignment;
return match obj.finish(&mut result) {
Ok(()) => {
assert!(result.mmap.is_some(), "no reserve");
let mmap = result.mmap.expect("reserve not called");
assert_eq!(mmap.len(), result.len);
Ok(MmapVecWrapper(mmap))
}
Err(e) => match result.err.take() {
Some(original) => Err(original.context(e)),
None => Err(e),
},
};
/// Helper struct to implement the `WritableBuffer` trait from the `object`
/// crate.
///
/// This enables writing an object directly into an mmap'd memory so it's
/// immediately usable for execution after compilation. This implementation
/// relies on a call to `reserve` happening once up front with all the needed
/// data, and the mmap internally does not attempt to grow afterwards.
#[derive(Default)]
struct ObjectMmap {
mmap: Option<MmapVec>,
len: usize,
alignment: usize,
err: Option<Error>,
}
impl WritableBuffer for ObjectMmap {
fn len(&self) -> usize {
self.len
}
fn reserve(&mut self, additional: usize) -> Result<(), ()> {
assert!(self.mmap.is_none(), "cannot reserve twice");
self.mmap = match MmapVec::with_capacity_and_alignment(additional, self.alignment) {
Ok(mmap) => Some(mmap),
Err(e) => {
self.err = Some(e);
return Err(());
}
};
Ok(())
}
fn resize(&mut self, new_len: usize) {
// Resizing always appends 0 bytes and since new mmaps start out as 0
// bytes we don't actually need to do anything as part of this other
// than update our own length.
if new_len <= self.len {
return;
}
self.len = new_len;
}
fn write_bytes(&mut self, val: &[u8]) {
let mmap = self.mmap.as_mut().expect("write before reserve");
// SAFETY: the `mmap` has not be made readonly yet so it should
// be safe to mutate it.
unsafe {
mmap.as_mut_slice()[self.len..][..val.len()].copy_from_slice(val);
}
self.len += val.len();
}
}
}
}