//! Defines the `Backend` trait.
use cretonne_codegen::isa::TargetIsa;
use cretonne_codegen::Context;
use cretonne_codegen::{binemit, ir};
use std::marker;
use DataContext;
use Linkage;
use ModuleNamespace;
use ModuleResult;
/// A `Backend` implements the functionality needed to support a `Module`.
pub trait Backend
where
Self: marker::Sized,
{
/// A builder for constructing `Backend` instances.
type Builder;
/// The results of compiling a function.
type CompiledFunction;
/// The results of "compiling" a data object.
type CompiledData;
/// The completed output artifact for a function, if this is meaningful for
/// the `Backend`.
type FinalizedFunction;
/// The completed output artifact for a data object, if this is meaningful for
/// the `Backend`.
type FinalizedData;
/// This is an object returned by `Module`'s
/// [`finish`](struct.Module.html#method.finish) function,
/// if the `Backend` has a purpose for this.
type Product;
/// Create a new `Backend` instance.
fn new(Self::Builder) -> Self;
/// Return the `TargetIsa` to compile for.
fn isa(&self) -> &TargetIsa;
/// Declare a function.
fn declare_function(&mut self, name: &str, linkage: Linkage);
/// Declare a data object.
fn declare_data(&mut self, name: &str, linkage: Linkage, writable: bool);
/// Define a function, producing the function body from the given `Context`.
///
/// Functions must be declared before being defined.
fn define_function(
&mut self,
name: &str,
ctx: &Context,
namespace: &ModuleNamespace<Self>,
code_size: u32,
) -> ModuleResult<Self::CompiledFunction>;
/// Define a zero-initialized data object of the given size.
///
/// Data objects must be declared before being defined.
fn define_data(
&mut self,
name: &str,
data_ctx: &DataContext,
namespace: &ModuleNamespace<Self>,
) -> ModuleResult<Self::CompiledData>;
/// Write the address of `what` into the data for `data` at `offset`. `data` must refer to a
/// defined data object.
fn write_data_funcaddr(
&mut self,
data: &mut Self::CompiledData,
offset: usize,
what: ir::FuncRef,
);
/// Write the address of `what` plus `addend` into the data for `data` at `offset`. `data` must
/// refer to a defined data object.
fn write_data_dataaddr(
&mut self,
data: &mut Self::CompiledData,
offset: usize,
what: ir::GlobalValue,
addend: binemit::Addend,
);
/// Perform all outstanding relocations on the given function. This requires all `Local`
/// and `Export` entities referenced to be defined.
fn finalize_function(
&mut self,
func: &Self::CompiledFunction,
namespace: &ModuleNamespace<Self>,
) -> Self::FinalizedFunction;
/// Perform all outstanding relocations on the given data object. This requires all
/// `Local` and `Export` entities referenced to be defined.
fn finalize_data(
&mut self,
data: &Self::CompiledData,
namespace: &ModuleNamespace<Self>,
) -> Self::FinalizedData;
/// Consume this `Backend` and return a result. Some implementations may
/// provide additional functionality through this result.
fn finish(self) -> Self::Product;
}