Files
wasmtime/lib/module/src/module.rs

642 lines
22 KiB
Rust

//! Defines `Module` and related types.
// TODO: Should `ir::Function` really have a `name`?
// TODO: Factor out `ir::Function`'s `ext_funcs` and `global_values` into a struct
// shared with `DataContext`?
use cranelift_codegen::entity::{EntityRef, PrimaryMap};
use cranelift_codegen::{binemit, ir, CodegenError, Context};
use data_context::DataContext;
use std::borrow::ToOwned;
use std::collections::HashMap;
use std::string::String;
use Backend;
/// A function identifier for use in the `Module` interface.
#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct FuncId(u32);
entity_impl!(FuncId, "funcid");
/// Function identifiers are namespace 0 in `ir::ExternalName`
impl From<FuncId> for ir::ExternalName {
fn from(id: FuncId) -> Self {
ir::ExternalName::User {
namespace: 0,
index: id.0,
}
}
}
/// A data object identifier for use in the `Module` interface.
#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct DataId(u32);
entity_impl!(DataId, "dataid");
/// Data identifiers are namespace 1 in `ir::ExternalName`
impl From<DataId> for ir::ExternalName {
fn from(id: DataId) -> Self {
ir::ExternalName::User {
namespace: 1,
index: id.0,
}
}
}
/// Linkage refers to where an entity is defined and who can see it.
#[derive(Copy, Clone, PartialEq, Eq)]
pub enum Linkage {
/// Defined outside of a module.
Import,
/// Defined inside the module, but not visible outside it.
Local,
/// Defined inside the module, visible outside it, and may be preempted.
Preemptible,
/// Defined inside the module, and visible outside it.
Export,
}
impl Linkage {
fn merge(a: Self, b: Self) -> Self {
match a {
Linkage::Export => Linkage::Export,
Linkage::Preemptible => match b {
Linkage::Export => Linkage::Export,
_ => Linkage::Preemptible,
},
Linkage::Local => match b {
Linkage::Export => Linkage::Export,
Linkage::Preemptible => Linkage::Preemptible,
_ => Linkage::Local,
},
Linkage::Import => b,
}
}
/// Test whether this linkage can have a definition.
pub fn is_definable(self) -> bool {
match self {
Linkage::Import => false,
Linkage::Local | Linkage::Preemptible | Linkage::Export => true,
}
}
/// Test whether this linkage will have a definition that cannot be preempted.
pub fn is_final(self) -> bool {
match self {
Linkage::Import | Linkage::Preemptible => false,
Linkage::Local | Linkage::Export => true,
}
}
}
/// A declared name may refer to either a function or data declaration
#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)]
pub enum FuncOrDataId {
/// When it's a FuncId
Func(FuncId),
/// When it's a DataId
Data(DataId),
}
/// Mapping to `ir::ExternalName` is trivial based on the `FuncId` and `DataId` mapping.
impl From<FuncOrDataId> for ir::ExternalName {
fn from(id: FuncOrDataId) -> Self {
match id {
FuncOrDataId::Func(funcid) => Self::from(funcid),
FuncOrDataId::Data(dataid) => Self::from(dataid),
}
}
}
/// Information about a function which can be called.
pub struct FunctionDeclaration {
pub name: String,
pub linkage: Linkage,
pub signature: ir::Signature,
}
/// Error messages for all `Module` and `Backend` methods
#[derive(Fail, Debug)]
pub enum ModuleError {
/// Indicates an identifier was used before it was declared
#[fail(display = "Undeclared identifier: {}", _0)]
Undeclared(String),
/// Indicates an identifier was used contrary to the way it was declared
#[fail(display = "Incompatible declaration of identifier: {}", _0)]
IncompatibleDeclaration(String),
/// Indicates an identifier was defined more than once
#[fail(display = "Duplicate definition of identifier: {}", _0)]
DuplicateDefinition(String),
/// Indicates an identifier was defined, but was declared as an import
#[fail(display = "Invalid to define identifier declared as an import: {}", _0)]
InvalidImportDefinition(String),
/// Wraps a `cranelift-codegen` error
#[fail(display = "Compilation error: {}", _0)]
Compilation(CodegenError),
/// Wraps a generic error from a backend
#[fail(display = "Backend error: {}", _0)]
Backend(String),
}
/// A convenient alias for a `Result` that uses `ModuleError` as the error type.
pub type ModuleResult<T> = Result<T, ModuleError>;
/// A function belonging to a `Module`.
struct ModuleFunction<B>
where
B: Backend,
{
/// The function declaration.
decl: FunctionDeclaration,
/// The compiled artifact, once it's available.
compiled: Option<B::CompiledFunction>,
/// A flag indicating whether the function has been finalized.
finalized: bool,
}
impl<B> ModuleFunction<B>
where
B: Backend,
{
fn merge(&mut self, linkage: Linkage, sig: &ir::Signature) -> Result<(), ModuleError> {
self.decl.linkage = Linkage::merge(self.decl.linkage, linkage);
if &self.decl.signature != sig {
return Err(ModuleError::IncompatibleDeclaration(self.decl.name.clone()));
}
Ok(())
}
}
/// Information about a data object which can be accessed.
pub struct DataDeclaration {
pub name: String,
pub linkage: Linkage,
pub writable: bool,
}
/// A data object belonging to a `Module`.
struct ModuleData<B>
where
B: Backend,
{
/// The data object declaration.
decl: DataDeclaration,
/// The "compiled" artifact, once it's available.
compiled: Option<B::CompiledData>,
/// A flag indicating whether the data object has been finalized.
finalized: bool,
}
impl<B> ModuleData<B>
where
B: Backend,
{
fn merge(&mut self, linkage: Linkage, writable: bool) {
self.decl.linkage = Linkage::merge(self.decl.linkage, linkage);
self.decl.writable = self.decl.writable || writable;
}
}
/// The functions and data objects belonging to a module.
struct ModuleContents<B>
where
B: Backend,
{
functions: PrimaryMap<FuncId, ModuleFunction<B>>,
data_objects: PrimaryMap<DataId, ModuleData<B>>,
}
impl<B> ModuleContents<B>
where
B: Backend,
{
fn get_function_info(&self, name: &ir::ExternalName) -> &ModuleFunction<B> {
if let ir::ExternalName::User { namespace, index } = *name {
debug_assert_eq!(namespace, 0);
let func = FuncId::new(index as usize);
&self.functions[func]
} else {
panic!("unexpected ExternalName kind {}", name)
}
}
/// Get the `DataDeclaration` for the function named by `name`.
fn get_data_info(&self, name: &ir::ExternalName) -> &ModuleData<B> {
if let ir::ExternalName::User { namespace, index } = *name {
debug_assert_eq!(namespace, 1);
let data = DataId::new(index as usize);
&self.data_objects[data]
} else {
panic!("unexpected ExternalName kind {}", name)
}
}
}
/// This provides a view to the state of a module which allows `ir::ExternalName`s to be translated
/// into `FunctionDeclaration`s and `DataDeclaration`s.
pub struct ModuleNamespace<'a, B: 'a>
where
B: Backend,
{
contents: &'a ModuleContents<B>,
}
impl<'a, B> ModuleNamespace<'a, B>
where
B: Backend,
{
/// Get the `FunctionDeclaration` for the function named by `name`.
pub fn get_function_decl(&self, name: &ir::ExternalName) -> &FunctionDeclaration {
&self.contents.get_function_info(name).decl
}
/// Get the `DataDeclaration` for the function named by `name`.
pub fn get_data_decl(&self, name: &ir::ExternalName) -> &DataDeclaration {
&self.contents.get_data_info(name).decl
}
/// Get the definition for the function named by `name`, along with its name
/// and signature.
pub fn get_function_definition(
&self,
name: &ir::ExternalName,
) -> (Option<&B::CompiledFunction>, &str, &ir::Signature) {
let info = self.contents.get_function_info(name);
debug_assert_eq!(info.decl.linkage.is_definable(), info.compiled.is_some());
(
info.compiled.as_ref(),
&info.decl.name,
&info.decl.signature,
)
}
/// Get the definition for the data object named by `name`, along with its name
/// and writable flag
pub fn get_data_definition(
&self,
name: &ir::ExternalName,
) -> (Option<&B::CompiledData>, &str, bool) {
let info = self.contents.get_data_info(name);
debug_assert_eq!(info.decl.linkage.is_definable(), info.compiled.is_some());
(info.compiled.as_ref(), &info.decl.name, info.decl.writable)
}
/// Return whether `name` names a function, rather than a data object.
pub fn is_function(&self, name: &ir::ExternalName) -> bool {
if let ir::ExternalName::User { namespace, .. } = *name {
namespace == 0
} else {
panic!("unexpected ExternalName kind {}", name)
}
}
}
/// A `Module` is a utility for collecting functions and data objects, and linking them together.
pub struct Module<B>
where
B: Backend,
{
names: HashMap<String, FuncOrDataId>,
contents: ModuleContents<B>,
backend: B,
}
impl<B> Module<B>
where
B: Backend,
{
/// Create a new `Module`.
pub fn new(backend_builder: B::Builder) -> Self {
Self {
names: HashMap::new(),
contents: ModuleContents {
functions: PrimaryMap::new(),
data_objects: PrimaryMap::new(),
},
backend: B::new(backend_builder),
}
}
/// Get the module identifier for a given name, if that name
/// has been declared.
pub fn get_name(&self, name: &str) -> Option<FuncOrDataId> {
self.names.get(name).cloned()
}
/// Return then pointer type for the current target.
pub fn pointer_type(&self) -> ir::types::Type {
self.backend.isa().pointer_type()
}
/// Create a new `Context` initialized for use with this `Module`.
///
/// This ensures that the `Context` is initialized with the default calling
/// convention for the `TargetIsa`.
pub fn make_context(&self) -> Context {
let mut ctx = Context::new();
ctx.func.signature.call_conv = self.backend.isa().flags().call_conv();
ctx
}
/// Create a new `Context` initialized for use with this `Module`.
///
/// This ensures that the `Context` is initialized with the default calling
/// convention for the `TargetIsa`.
pub fn clear_context(&self, ctx: &mut Context) {
ctx.clear();
ctx.func.signature.call_conv = self.backend.isa().flags().call_conv();
}
/// Declare a function in this module.
pub fn declare_function(
&mut self,
name: &str,
linkage: Linkage,
signature: &ir::Signature,
) -> ModuleResult<FuncId> {
// TODO: Can we avoid allocating names so often?
use std::collections::hash_map::Entry::*;
match self.names.entry(name.to_owned()) {
Occupied(entry) => match *entry.get() {
FuncOrDataId::Func(id) => {
let existing = &mut self.contents.functions[id];
existing.merge(linkage, signature)?;
self.backend.declare_function(name, existing.decl.linkage);
Ok(id)
}
FuncOrDataId::Data(..) => {
Err(ModuleError::IncompatibleDeclaration(name.to_owned()))
}
},
Vacant(entry) => {
let id = self.contents.functions.push(ModuleFunction {
decl: FunctionDeclaration {
name: name.to_owned(),
linkage,
signature: signature.clone(),
},
compiled: None,
finalized: false,
});
entry.insert(FuncOrDataId::Func(id));
self.backend.declare_function(name, linkage);
Ok(id)
}
}
}
/// Declare a data object in this module.
pub fn declare_data(
&mut self,
name: &str,
linkage: Linkage,
writable: bool,
) -> ModuleResult<DataId> {
// TODO: Can we avoid allocating names so often?
use std::collections::hash_map::Entry::*;
match self.names.entry(name.to_owned()) {
Occupied(entry) => match *entry.get() {
FuncOrDataId::Data(id) => {
let existing = &mut self.contents.data_objects[id];
existing.merge(linkage, writable);
self.backend
.declare_data(name, existing.decl.linkage, existing.decl.writable);
Ok(id)
}
FuncOrDataId::Func(..) => {
Err(ModuleError::IncompatibleDeclaration(name.to_owned()))
}
},
Vacant(entry) => {
let id = self.contents.data_objects.push(ModuleData {
decl: DataDeclaration {
name: name.to_owned(),
linkage,
writable,
},
compiled: None,
finalized: false,
});
entry.insert(FuncOrDataId::Data(id));
self.backend.declare_data(name, linkage, writable);
Ok(id)
}
}
}
/// Use this when you're building the IR of a function to reference a function.
///
/// TODO: Coalesce redundant decls and signatures.
/// TODO: Look into ways to reduce the risk of using a FuncRef in the wrong function.
pub fn declare_func_in_func(&self, func: FuncId, in_func: &mut ir::Function) -> ir::FuncRef {
let decl = &self.contents.functions[func].decl;
let signature = in_func.import_signature(decl.signature.clone());
let colocated = decl.linkage.is_final();
in_func.import_function(ir::ExtFuncData {
name: ir::ExternalName::user(0, func.index() as u32),
signature,
colocated,
})
}
/// Use this when you're building the IR of a function to reference a data object.
///
/// TODO: Same as above.
pub fn declare_data_in_func(&self, data: DataId, func: &mut ir::Function) -> ir::GlobalValue {
let decl = &self.contents.data_objects[data].decl;
let colocated = decl.linkage.is_final();
func.create_global_value(ir::GlobalValueData::Sym {
name: ir::ExternalName::user(1, data.index() as u32),
colocated,
})
}
/// TODO: Same as above.
pub fn declare_func_in_data(&self, func: FuncId, ctx: &mut DataContext) -> ir::FuncRef {
ctx.import_function(ir::ExternalName::user(0, func.index() as u32))
}
/// TODO: Same as above.
pub fn declare_data_in_data(&self, data: DataId, ctx: &mut DataContext) -> ir::GlobalValue {
ctx.import_global_value(ir::ExternalName::user(1, data.index() as u32))
}
/// Define a function, producing the function body from the given `Context`.
pub fn define_function(&mut self, func: FuncId, ctx: &mut Context) -> ModuleResult<()> {
let compiled = {
let code_size = ctx.compile(self.backend.isa()).map_err(|e| {
dbg!(
"defining function {}: {}",
func,
ctx.func.display(self.backend.isa())
);
ModuleError::Compilation(e)
})?;
let info = &self.contents.functions[func];
if info.compiled.is_some() {
return Err(ModuleError::DuplicateDefinition(info.decl.name.clone()));
}
if !info.decl.linkage.is_definable() {
return Err(ModuleError::InvalidImportDefinition(info.decl.name.clone()));
}
Some(self.backend.define_function(
&info.decl.name,
ctx,
&ModuleNamespace::<B> {
contents: &self.contents,
},
code_size,
)?)
};
self.contents.functions[func].compiled = compiled;
Ok(())
}
/// Define a function, producing the data contents from the given `DataContext`.
pub fn define_data(&mut self, data: DataId, data_ctx: &DataContext) -> ModuleResult<()> {
let compiled = {
let info = &self.contents.data_objects[data];
if info.compiled.is_some() {
return Err(ModuleError::DuplicateDefinition(info.decl.name.clone()));
}
if !info.decl.linkage.is_definable() {
return Err(ModuleError::InvalidImportDefinition(info.decl.name.clone()));
}
Some(self.backend.define_data(
&info.decl.name,
data_ctx,
&ModuleNamespace::<B> {
contents: &self.contents,
},
)?)
};
self.contents.data_objects[data].compiled = compiled;
Ok(())
}
/// Write the address of `what` into the data for `data` at `offset`. `data` must refer to a
/// defined data object.
pub fn write_data_funcaddr(&mut self, data: DataId, offset: usize, what: ir::FuncRef) {
let info = &mut self.contents.data_objects[data];
debug_assert!(
info.decl.linkage.is_definable(),
"imported data cannot contain references"
);
self.backend.write_data_funcaddr(
&mut info.compiled
.as_mut()
.expect("`data` must refer to a defined data object"),
offset,
what,
);
}
/// Write the address of `what` plus `addend` into the data for `data` at `offset`. `data` must
/// refer to a defined data object.
pub fn write_data_dataaddr(
&mut self,
data: DataId,
offset: usize,
what: ir::GlobalValue,
addend: binemit::Addend,
) {
let info = &mut self.contents.data_objects[data];
debug_assert!(
info.decl.linkage.is_definable(),
"imported data cannot contain references"
);
self.backend.write_data_dataaddr(
&mut info.compiled
.as_mut()
.expect("`data` must refer to a defined data object"),
offset,
what,
addend,
);
}
/// Perform all outstanding relocations on the given function. This requires all `Local`
/// and `Export` entities referenced to be defined.
pub fn finalize_function(&mut self, func: FuncId) -> B::FinalizedFunction {
let output = {
let info = &self.contents.functions[func];
debug_assert!(
info.decl.linkage.is_definable(),
"imported function cannot be finalized"
);
self.backend.finalize_function(
info.compiled
.as_ref()
.expect("function must be compiled before it can be finalized"),
&ModuleNamespace::<B> {
contents: &self.contents,
},
)
};
self.contents.functions[func].finalized = true;
output
}
/// Perform all outstanding relocations on the given data object. This requires all
/// `Local` and `Export` entities referenced to be defined.
pub fn finalize_data(&mut self, data: DataId) -> B::FinalizedData {
let output = {
let info = &self.contents.data_objects[data];
debug_assert!(
info.decl.linkage.is_definable(),
"imported data cannot be finalized"
);
self.backend.finalize_data(
info.compiled
.as_ref()
.expect("data object must be compiled before it can be finalized"),
&ModuleNamespace::<B> {
contents: &self.contents,
},
)
};
self.contents.data_objects[data].finalized = true;
output
}
/// Finalize all functions and data objects. Note that this doesn't return the
/// final artifacts returned from `finalize_function` or `finalize_data`.
pub fn finalize_all(&mut self) {
// TODO: Could we use something like `into_iter()` here?
for info in self.contents.functions.values() {
if info.decl.linkage.is_definable() && !info.finalized {
self.backend.finalize_function(
info.compiled
.as_ref()
.expect("function must be compiled before it can be finalized"),
&ModuleNamespace::<B> {
contents: &self.contents,
},
);
}
}
for info in self.contents.data_objects.values() {
if info.decl.linkage.is_definable() && !info.finalized {
self.backend.finalize_data(
info.compiled
.as_ref()
.expect("data object must be compiled before it can be finalized"),
&ModuleNamespace::<B> {
contents: &self.contents,
},
);
}
}
}
/// Consume the module and return the resulting `Product`. Some `Backend`
/// implementations may provide additional functionality available after
/// a `Module` is complete.
pub fn finish(self) -> B::Product {
self.backend.finish()
}
}