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module.rs
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module.rs
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//! 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 super::HashMap;
use crate::data_context::DataContext;
use crate::Backend;
use cranelift_codegen::binemit;
use cranelift_codegen::entity::{entity_impl, PrimaryMap};
use cranelift_codegen::{ir, isa, CodegenError, Context};
use std::borrow::ToOwned;
use std::string::String;
use thiserror::Error;
/// 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 {
Self::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 {
Self::User {
namespace: 1,
index: id.0,
}
}
}
/// Linkage refers to where an entity is defined and who can see it.
#[derive(Copy, Clone, Debug, 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, visible inside the current static linkage unit, but not outside.
///
/// A static linkage unit is the combination of all object files passed to a linker to create
/// an executable or dynamic library.
Hidden,
/// Defined inside the module, and visible outside it.
Export,
}
impl Linkage {
fn merge(a: Self, b: Self) -> Self {
match a {
Self::Export => Self::Export,
Self::Hidden => match b {
Self::Export => Self::Export,
Self::Preemptible => Self::Preemptible,
_ => Self::Hidden,
},
Self::Preemptible => match b {
Self::Export => Self::Export,
_ => Self::Preemptible,
},
Self::Local => match b {
Self::Export => Self::Export,
Self::Hidden => Self::Hidden,
Self::Preemptible => Self::Preemptible,
Self::Local | Self::Import => Self::Local,
},
Self::Import => b,
}
}
/// Test whether this linkage can have a definition.
pub fn is_definable(self) -> bool {
match self {
Self::Import => false,
Self::Local | Self::Preemptible | Self::Hidden | Self::Export => true,
}
}
/// Test whether this linkage will have a definition that cannot be preempted.
pub fn is_final(self) -> bool {
match self {
Self::Import | Self::Preemptible => false,
Self::Local | Self::Hidden | Self::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,
}
impl FunctionDeclaration {
fn merge(&mut self, linkage: Linkage, sig: &ir::Signature) -> Result<(), ModuleError> {
self.linkage = Linkage::merge(self.linkage, linkage);
if &self.signature != sig {
return Err(ModuleError::IncompatibleSignature(
self.name.clone(),
self.signature.clone(),
sig.clone(),
));
}
Ok(())
}
}
/// Error messages for all `Module` and `Backend` methods
#[derive(Error, Debug)]
pub enum ModuleError {
/// Indicates an identifier was used before it was declared
#[error("Undeclared identifier: {0}")]
Undeclared(String),
/// Indicates an identifier was used as data/function first, but then used as the other
#[error("Incompatible declaration of identifier: {0}")]
IncompatibleDeclaration(String),
/// Indicates a function identifier was declared with a
/// different signature than declared previously
#[error("Function {0} signature {2:?} is incompatible with previous declaration {1:?}")]
IncompatibleSignature(String, ir::Signature, ir::Signature),
/// Indicates an identifier was defined more than once
#[error("Duplicate definition of identifier: {0}")]
DuplicateDefinition(String),
/// Indicates an identifier was defined, but was declared as an import
#[error("Invalid to define identifier declared as an import: {0}")]
InvalidImportDefinition(String),
/// Indicates a too-long function was defined
#[error("Function {0} exceeds the maximum function size")]
FunctionTooLarge(String),
/// Wraps a `cranelift-codegen` error
#[error("Compilation error: {0}")]
Compilation(#[from] CodegenError),
/// Wraps a generic error from a backend
#[error("Backend error: {0}")]
Backend(#[source] anyhow::Error),
}
/// A convenient alias for a `Result` that uses `ModuleError` as the error type.
pub type ModuleResult<T> = Result<T, ModuleError>;
/// Information about a data object which can be accessed.
pub struct DataDeclaration {
pub name: String,
pub linkage: Linkage,
pub writable: bool,
pub tls: bool,
pub align: Option<u8>,
}
impl DataDeclaration {
fn merge(&mut self, linkage: Linkage, writable: bool, tls: bool, align: Option<u8>) {
self.linkage = Linkage::merge(self.linkage, linkage);
self.writable = self.writable || writable;
self.align = self.align.max(align);
assert_eq!(
self.tls, tls,
"Can't change TLS data object to normal or in the opposite way",
);
}
}
/// This provides a view to the state of a module which allows `ir::ExternalName`s to be translated
/// into `FunctionDeclaration`s and `DataDeclaration`s.
#[derive(Default)]
pub struct ModuleDeclarations {
names: HashMap<String, FuncOrDataId>,
functions: PrimaryMap<FuncId, FunctionDeclaration>,
data_objects: PrimaryMap<DataId, DataDeclaration>,
}
impl ModuleDeclarations {
/// 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).copied()
}
/// Get the `FuncId` for the function named by `name`.
pub fn get_function_id(&self, name: &ir::ExternalName) -> FuncId {
if let ir::ExternalName::User { namespace, index } = *name {
debug_assert_eq!(namespace, 0);
FuncId::from_u32(index)
} else {
panic!("unexpected ExternalName kind {}", name)
}
}
/// Get the `DataId` for the data object named by `name`.
pub fn get_data_id(&self, name: &ir::ExternalName) -> DataId {
if let ir::ExternalName::User { namespace, index } = *name {
debug_assert_eq!(namespace, 1);
DataId::from_u32(index)
} else {
panic!("unexpected ExternalName kind {}", name)
}
}
/// Get the `FunctionDeclaration` for the function named by `name`.
pub fn get_function_decl(&self, func_id: FuncId) -> &FunctionDeclaration {
&self.functions[func_id]
}
/// Get the `DataDeclaration` for the data object named by `name`.
pub fn get_data_decl(&self, data_id: DataId) -> &DataDeclaration {
&self.data_objects[data_id]
}
/// 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)
}
}
/// Declare a function in this module.
pub fn declare_function(
&mut self,
name: &str,
linkage: Linkage,
signature: &ir::Signature,
) -> ModuleResult<(FuncId, &FunctionDeclaration)> {
// TODO: Can we avoid allocating names so often?
use super::hash_map::Entry::*;
match self.names.entry(name.to_owned()) {
Occupied(entry) => match *entry.get() {
FuncOrDataId::Func(id) => {
let existing = &mut self.functions[id];
existing.merge(linkage, signature)?;
Ok((id, existing))
}
FuncOrDataId::Data(..) => {
Err(ModuleError::IncompatibleDeclaration(name.to_owned()))
}
},
Vacant(entry) => {
let id = self.functions.push(FunctionDeclaration {
name: name.to_owned(),
linkage,
signature: signature.clone(),
});
entry.insert(FuncOrDataId::Func(id));
Ok((id, &self.functions[id]))
}
}
}
/// Declare a data object in this module.
pub fn declare_data(
&mut self,
name: &str,
linkage: Linkage,
writable: bool,
tls: bool,
align: Option<u8>, // An alignment bigger than 128 is unlikely
) -> ModuleResult<(DataId, &DataDeclaration)> {
// TODO: Can we avoid allocating names so often?
use super::hash_map::Entry::*;
match self.names.entry(name.to_owned()) {
Occupied(entry) => match *entry.get() {
FuncOrDataId::Data(id) => {
let existing = &mut self.data_objects[id];
existing.merge(linkage, writable, tls, align);
Ok((id, existing))
}
FuncOrDataId::Func(..) => {
Err(ModuleError::IncompatibleDeclaration(name.to_owned()))
}
},
Vacant(entry) => {
let id = self.data_objects.push(DataDeclaration {
name: name.to_owned(),
linkage,
writable,
tls,
align,
});
entry.insert(FuncOrDataId::Data(id));
Ok((id, &self.data_objects[id]))
}
}
}
}
/// A `Module` is a utility for collecting functions and data objects, and linking them together.
pub struct Module<B>
where
B: Backend,
{
backend: B,
}
/// Information about the compiled function.
pub struct ModuleCompiledFunction {
/// The size of the compiled function.
pub size: binemit::CodeOffset,
}
impl<B> Module<B>
where
B: Backend,
{
/// Create a new `Module`.
pub fn new(backend_builder: B::Builder) -> Self {
Self {
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.backend.declarations().get_name(name)
}
/// Return the target information needed by frontends to produce Cranelift IR
/// for the current target.
pub fn target_config(&self) -> isa::TargetFrontendConfig {
self.isa().frontend_config()
}
/// 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.isa().default_call_conv();
ctx
}
/// Clear the given `Context` and reset it for use with a new function.
///
/// 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.isa().default_call_conv();
}
/// Create a new empty `Signature` with the default calling convention for
/// the `TargetIsa`, to which parameter and return types can be added for
/// declaring a function to be called by this `Module`.
pub fn make_signature(&self) -> ir::Signature {
ir::Signature::new(self.isa().default_call_conv())
}
/// Clear the given `Signature` and reset for use with a new function.
///
/// This ensures that the `Signature` is initialized with the default
/// calling convention for the `TargetIsa`.
pub fn clear_signature(&self, sig: &mut ir::Signature) {
sig.clear(self.isa().default_call_conv());
}
/// Declare a function in this module.
pub fn declare_function(
&mut self,
name: &str,
linkage: Linkage,
signature: &ir::Signature,
) -> ModuleResult<FuncId> {
self.backend.declare_function(name, linkage, signature)
}
/// Declare a data object in this module.
pub fn declare_data(
&mut self,
name: &str,
linkage: Linkage,
writable: bool,
tls: bool,
align: Option<u8>, // An alignment bigger than 128 is unlikely
) -> ModuleResult<DataId> {
self.backend
.declare_data(name, linkage, writable, tls, align)
}
/// 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.backend.declarations().functions[func];
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.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.backend.declarations().data_objects[data];
let colocated = decl.linkage.is_final();
func.create_global_value(ir::GlobalValueData::Symbol {
name: ir::ExternalName::user(1, data.as_u32()),
offset: ir::immediates::Imm64::new(0),
colocated,
tls: decl.tls,
})
}
/// 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.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.as_u32()))
}
/// Define a function, producing the function body from the given `Context`.
///
/// Returns the size of the function's code and constant data.
///
/// Note: After calling this function the given `Context` will contain the compiled function.
pub fn define_function<TS>(
&mut self,
func: FuncId,
ctx: &mut Context,
trap_sink: &mut TS,
) -> ModuleResult<ModuleCompiledFunction>
where
TS: binemit::TrapSink,
{
self.backend.define_function(func, ctx, trap_sink)
}
/// Define a function, taking the function body from the given `bytes`.
///
/// This function is generally only useful if you need to precisely specify
/// the emitted instructions for some reason; otherwise, you should use
/// `define_function`.
///
/// Returns the size of the function's code.
pub fn define_function_bytes(
&mut self,
func: FuncId,
bytes: &[u8],
) -> ModuleResult<ModuleCompiledFunction> {
self.backend.define_function_bytes(func, bytes)
}
/// Define a data object, producing the data contents from the given `DataContext`.
pub fn define_data(&mut self, data: DataId, data_ctx: &DataContext) -> ModuleResult<()> {
self.backend.define_data(data, data_ctx)
}
/// Return the target isa
pub fn isa(&self) -> &dyn isa::TargetIsa {
self.backend.isa()
}
/// 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()
}
}