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core: document codegen/model (incomplete)

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This commit is contained in:
lyken 2024-07-16 13:05:16 +08:00
parent 496171a4a5
commit d3a5c5a48a
4 changed files with 113 additions and 38 deletions
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16
nac3core/src/codegen/model/core.rs
View File

@ -22,10 +22,13 @@ pub trait ModelValue<'ctx>: Clone + Copy {
fn get_llvm_value(&self) -> BasicValueEnum<'ctx>;
}
// Should have been within [`Model<ctx>`],
// Should have been within [`Model<'ctx>`],
// but rust object safety requirements made it necessary to
// split this interface out
pub trait CanCheckLLVMType<'ctx> {
/// Check if `scrutinee` matches the same LLVM type of this [`Model<'ctx>`].
///
/// If they don't not match, a human-readable error message is returned.
fn check_llvm_type(
&self,
ctx: &'ctx Context,
@ -33,12 +36,22 @@ pub trait CanCheckLLVMType<'ctx> {
) -> Result<(), String>;
}
/// A [`Model`] is a type-safe concrete representation of a complex LLVM type.
pub trait Model<'ctx>: Clone + Copy + CanCheckLLVMType<'ctx> + Sized {
/// The values that inhabit this [`Model<'ctx>`].
///
/// ...that is the type of wrapper that wraps the LLVM values that inhabit [`Model<'ctx>::get_llvm_type()`].
type Value: ModelValue<'ctx>;
/// Get the [`BasicTypeEnum<'ctx>`] this [`Model<'ctx>`] is representing.
fn get_llvm_type(&self, ctx: &'ctx Context) -> BasicTypeEnum<'ctx>;
/// Cast an [`AnyValueEnum<'ctx>`] into a [`Self::Value`].
///
/// Panics if `value` cannot pass [`CanCheckLLVMType::check_llvm_type()`].
fn review(&self, ctx: &'ctx Context, value: AnyValueEnum<'ctx>) -> Self::Value;
/// Build an instruction to allocate a value of [`Model::get_llvm_type`].
fn alloca(&self, ctx: &CodeGenContext<'ctx, '_>, name: &str) -> Pointer<'ctx, Self> {
Pointer {
element: *self,
@ -46,6 +59,7 @@ pub trait Model<'ctx>: Clone + Copy + CanCheckLLVMType<'ctx> + Sized {
}
}
/// Build an instruction to allocate an array of [`Model::get_llvm_type`].
fn array_alloca(
&self,
ctx: &CodeGenContext<'ctx, '_>,

50
nac3core/src/codegen/model/gep.rs
View File

@ -66,9 +66,13 @@ impl<'ctx> FieldBuilder<'ctx> {
}
}
/// A marker trait to mark singleton struct that describes a particular LLVM structure.
pub trait IsStruct<'ctx>: Clone + Copy {
/// The type of the Rust `struct` that holds all the fields of this LLVM struct.
type Fields;
/// A cosmetic name for this struct.
/// TODO: Currently unused. To be used in error reporting.
fn struct_name(&self) -> &'static str;
fn build_fields(&self, builder: &mut FieldBuilder<'ctx>) -> Self::Fields;
@ -78,6 +82,7 @@ pub trait IsStruct<'ctx>: Clone + Copy {
self.build_fields(&mut builder)
}
/// Get the LLVM struct type this [`IsStruct<'ctx>`] is representing.
fn get_struct_type(&self, ctx: &'ctx Context) -> StructType<'ctx> {
let mut builder = FieldBuilder::new(ctx, self.struct_name());
self.build_fields(&mut builder); // Self::Fields is discarded
@ -86,6 +91,7 @@ pub trait IsStruct<'ctx>: Clone + Copy {
ctx.struct_type(&field_types, false)
}
/// Check if `scrutinee` matches the [`StructType<'ctx>`] this [`IsStruct<'ctx>`] is representing.
fn check_struct_type(
&self,
ctx: &'ctx Context,
@ -118,21 +124,12 @@ pub trait IsStruct<'ctx>: Clone + Copy {
}
}
/// A [`Model<'ctx>`] that represents an LLVM struct.
///
/// `self.0` contains a [`IsStruct<'ctx>`] that gives the details of the LLVM struct.
#[derive(Debug, Clone, Copy)]
pub struct StructModel<S>(pub S);
#[derive(Debug, Clone, Copy)]
pub struct Struct<'ctx, S> {
pub structure: S,
pub value: StructValue<'ctx>,
}
impl<'ctx, S: IsStruct<'ctx>> ModelValue<'ctx> for Struct<'ctx, S> {
fn get_llvm_value(&self) -> BasicValueEnum<'ctx> {
self.value.as_basic_value_enum()
}
}
impl<'ctx, S: IsStruct<'ctx>> CanCheckLLVMType<'ctx> for StructModel<S> {
fn check_llvm_type(
&self,
@ -164,7 +161,36 @@ impl<'ctx, S: IsStruct<'ctx>> Model<'ctx> for StructModel<S> {
}
}
#[derive(Debug, Clone, Copy)]
pub struct Struct<'ctx, S> {
pub structure: S,
pub value: StructValue<'ctx>,
}
impl<'ctx, S: IsStruct<'ctx>> ModelValue<'ctx> for Struct<'ctx, S> {
fn get_llvm_value(&self) -> BasicValueEnum<'ctx> {
self.value.as_basic_value_enum()
}
}
impl<'ctx, S: IsStruct<'ctx>> Pointer<'ctx, StructModel<S>> {
/// Build an instruction that does `getelementptr` on an LLVM structure referenced by this pointer.
///
/// This provides a nice syntax to chain up `getelementptr` in an intuitive and type-safe way:
///
/// ```ignore
/// let ctx: &CodeGenContext<'ctx, '_>;
/// let ndarray: Pointer<'ctx, StructModel<NpArray<'ctx>>>;
/// ndarray.gep(ctx, |f| f.ndims).store();
/// ```
///
/// You might even write chains `gep`, i.e.,
/// ```ignore
/// my_struct
/// .gep(ctx, |f| f.thing1)
/// .gep(ctx, |f| f.value)
/// .store(ctx, my_value) // Equivalent to `my_struct.thing1.value = my_value`
/// ```
pub fn gep<E, GetFieldFn>(
&self,
ctx: &CodeGenContext<'ctx, '_>,

76
nac3core/src/codegen/model/int.rs
View File

@ -8,6 +8,7 @@ use crate::codegen::CodeGenContext;
use super::core::*;
/// Helper function to check if `scrutinee` is the same as `expected_int_type`
fn check_int_llvm_type<'ctx>(
scrutinee: AnyTypeEnum<'ctx>,
expected_int_type: IntType<'ctx>,
@ -29,6 +30,8 @@ fn check_int_llvm_type<'ctx>(
Ok(())
}
/// Helper function to cast `scrutinee` is into an [`IntValue<'ctx>`].
/// The LLVM type of `scrutinee` will be checked with [`check_int_llvm_type`].
fn review_int_llvm_value<'ctx>(
value: AnyValueEnum<'ctx>,
expected_int_type: IntType<'ctx>,
@ -40,18 +43,18 @@ fn review_int_llvm_value<'ctx>(
Ok(value.into_int_value())
}
/// A model representing an [`IntType<'ctx>`].
///
/// Also see [`FixedIntModel`], which is more constrained than [`IntModel`]
/// but provides more type-safe mechanisms and even auto-derivation of [`BasicTypeEnum<'ctx>`]
/// for creating LLVM structures.
#[derive(Debug, Clone, Copy)]
pub struct IntModel<'ctx>(pub IntType<'ctx>);
/// An inhabitant of an [`IntModel<'ctx>`]
#[derive(Debug, Clone, Copy)]
pub struct Int<'ctx>(pub IntValue<'ctx>);
impl<'ctx> ModelValue<'ctx> for Int<'ctx> {
fn get_llvm_value(&self) -> BasicValueEnum<'ctx> {
self.0.as_basic_value_enum()
}
}
impl<'ctx> CanCheckLLVMType<'ctx> for IntModel<'ctx> {
fn check_llvm_type(
&self,
@ -76,6 +79,13 @@ impl<'ctx> Model<'ctx> for IntModel<'ctx> {
}
}
impl<'ctx> ModelValue<'ctx> for Int<'ctx> {
fn get_llvm_value(&self) -> BasicValueEnum<'ctx> {
self.0.as_basic_value_enum()
}
}
// Extra utilities for [`Int<'ctx>`]
impl<'ctx> Int<'ctx> {
#[must_use]
pub fn signed_cast_to_int(
@ -104,12 +114,18 @@ impl<'ctx> Int<'ctx> {
}
}
// Extra utilities for [`IntModel<'ctx>`]
impl<'ctx> IntModel<'ctx> {
/// Create a constant value that inhabits this [`IntModel<'ctx>`].
#[must_use]
pub fn constant(&self, value: u64) -> Int<'ctx> {
Int(self.0.const_int(value, false))
}
/// Check if `other` is fully compatible with this [`IntModel<'ctx>`].
///
/// This simply checks if the underlying [`IntType<'ctx>`] has
/// the same number of bits.
#[must_use]
pub fn same_as(&self, other: IntModel<'ctx>) -> bool {
// TODO: or `self.0 == other.0` would also work?
@ -117,6 +133,10 @@ impl<'ctx> IntModel<'ctx> {
}
}
/// A model representing a compile-time known [`IntType<'ctx>`].
///
/// Also see [`IntModel`], which is less constrained than [`FixedIntModel`],
/// but enables one to handle [`IntType<'ctx>`] that could be dynamic
#[derive(Debug, Clone, Copy, Default)]
pub struct FixedIntModel<T>(pub T);
@ -126,24 +146,6 @@ impl<T: IsFixedInt> FixedIntModel<T> {
}
}
#[derive(Debug, Clone, Copy)]
pub struct FixedInt<'ctx, T: IsFixedInt> {
pub int: T,
pub value: IntValue<'ctx>,
}
// Default instance is to enable `FieldBuilder::add_field_auto`
pub trait IsFixedInt: Clone + Copy + Default {
fn get_int_type(ctx: &Context) -> IntType<'_>;
fn get_bit_width() -> u32; // This is required, instead of only relying on get_int_type
}
impl<'ctx, T: IsFixedInt> ModelValue<'ctx> for FixedInt<'ctx, T> {
fn get_llvm_value(&self) -> BasicValueEnum<'ctx> {
self.value.as_basic_value_enum()
}
}
impl<'ctx, T: IsFixedInt> CanCheckLLVMType<'ctx> for FixedIntModel<T> {
fn check_llvm_type(
&self,
@ -173,6 +175,30 @@ impl<'ctx, T: IsFixedInt> FixedIntModel<T> {
}
}
/// An inhabitant of [`FixedIntModel<'ctx>`]
#[derive(Debug, Clone, Copy)]
pub struct FixedInt<'ctx, T: IsFixedInt> {
pub int: T,
pub value: IntValue<'ctx>,
}
/// A marker trait to mark singleton struct that describes a particular fixed integer type.
/// See [`Bool`], [`Byte`], [`Int32`], etc.
///
/// The [`Default`] trait is to enable auto-derivations for utilities like
/// [`FieldBuilder::add_field_auto`]
pub trait IsFixedInt: Clone + Copy + Default {
fn get_int_type(ctx: &Context) -> IntType<'_>;
fn get_bit_width() -> u32; // This is required, instead of only relying on get_int_type
}
impl<'ctx, T: IsFixedInt> ModelValue<'ctx> for FixedInt<'ctx, T> {
fn get_llvm_value(&self) -> BasicValueEnum<'ctx> {
self.value.as_basic_value_enum()
}
}
// Extra utilities for [`FixedInt<'ctx, T>`]
impl<'ctx, T: IsFixedInt> FixedInt<'ctx, T> {
pub fn to_int(self) -> Int<'ctx> {
Int(self.value)
@ -194,7 +220,7 @@ impl<'ctx, T: IsFixedInt> FixedInt<'ctx, T> {
}
}
// Some pre-defined fixed ints
// Some pre-defined fixed integers
#[derive(Debug, Clone, Copy, Default)]
pub struct Bool;

9
nac3core/src/codegen/model/pointer.rs
View File

@ -9,12 +9,19 @@ use crate::codegen::CodeGenContext;
use super::core::*;
/// An inhabitant of [`PointerModel<E>`]
#[derive(Debug, Clone, Copy)]
pub struct Pointer<'ctx, E: Model<'ctx>> {
pub element: E,
pub value: PointerValue<'ctx>,
}
/// A [`Model<'ctx>`] representing an LLVM [`PointerType<'ctx>`]
/// with *full* information on the element u
///
/// [`self.0`] contains [`Model<'ctx>`] that represents the
/// LLVM type of element of the [`PointerType<'ctx>`] is pointing at
/// (like `PointerType<'ctx>::get_element_type()`, but abstracted as a [`Model<'ctx>`]).
#[derive(Debug, Clone, Copy, Default)]
pub struct PointerModel<E>(pub E);
@ -25,10 +32,12 @@ impl<'ctx, E: Model<'ctx>> ModelValue<'ctx> for Pointer<'ctx, E> {
}
impl<'ctx, E: Model<'ctx>> Pointer<'ctx, E> {
/// Build an instruction to store a value into this pointer
pub fn store(&self, ctx: &CodeGenContext<'ctx, '_>, val: E::Value) {
ctx.builder.build_store(self.value, val.get_llvm_value()).unwrap();
}
/// Build an instruction to load a value from this pointer
pub fn load(&self, ctx: &CodeGenContext<'ctx, '_>, name: &str) -> E::Value {
let val = ctx.builder.build_load(self.value, name).unwrap();
self.element.review(ctx.ctx, val.as_any_value_enum())