]> git.proxmox.com Git - rustc.git/blobdiff - compiler/rustc_codegen_gcc/src/type_of.rs
New upstream version 1.57.0+dfsg1
[rustc.git] / compiler / rustc_codegen_gcc / src / type_of.rs
diff --git a/compiler/rustc_codegen_gcc/src/type_of.rs b/compiler/rustc_codegen_gcc/src/type_of.rs
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+use std::fmt::Write;
+
+use gccjit::{Struct, Type};
+use crate::rustc_codegen_ssa::traits::{BaseTypeMethods, DerivedTypeMethods, LayoutTypeMethods};
+use rustc_middle::bug;
+use rustc_middle::ty::{self, Ty, TypeFoldable};
+use rustc_middle::ty::layout::{FnAbiOf, LayoutOf, TyAndLayout};
+use rustc_middle::ty::print::with_no_trimmed_paths;
+use rustc_target::abi::{self, Abi, F32, F64, FieldsShape, Int, Integer, Pointer, PointeeInfo, Size, TyAbiInterface, Variants};
+use rustc_target::abi::call::{CastTarget, FnAbi, Reg};
+
+use crate::abi::{FnAbiGccExt, GccType};
+use crate::context::CodegenCx;
+use crate::type_::struct_fields;
+
+impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
+    fn type_from_unsigned_integer(&self, i: Integer) -> Type<'gcc> {
+        use Integer::*;
+        match i {
+            I8 => self.type_u8(),
+            I16 => self.type_u16(),
+            I32 => self.type_u32(),
+            I64 => self.type_u64(),
+            I128 => self.type_u128(),
+        }
+    }
+}
+
+pub fn uncached_gcc_type<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, layout: TyAndLayout<'tcx>, defer: &mut Option<(Struct<'gcc>, TyAndLayout<'tcx>)>) -> Type<'gcc> {
+    match layout.abi {
+        Abi::Scalar(_) => bug!("handled elsewhere"),
+        Abi::Vector { ref element, count } => {
+            let element = layout.scalar_gcc_type_at(cx, element, Size::ZERO);
+            return cx.context.new_vector_type(element, count);
+        },
+        Abi::ScalarPair(..) => {
+            return cx.type_struct(
+                &[
+                    layout.scalar_pair_element_gcc_type(cx, 0, false),
+                    layout.scalar_pair_element_gcc_type(cx, 1, false),
+                ],
+                false,
+            );
+        }
+        Abi::Uninhabited | Abi::Aggregate { .. } => {}
+    }
+
+    let name = match layout.ty.kind() {
+        // FIXME(eddyb) producing readable type names for trait objects can result
+        // in problematically distinct types due to HRTB and subtyping (see #47638).
+        // ty::Dynamic(..) |
+        ty::Adt(..) | ty::Closure(..) | ty::Foreign(..) | ty::Generator(..) | ty::Str
+            if !cx.sess().fewer_names() =>
+        {
+            let mut name = with_no_trimmed_paths(|| layout.ty.to_string());
+            if let (&ty::Adt(def, _), &Variants::Single { index }) =
+                (layout.ty.kind(), &layout.variants)
+            {
+                if def.is_enum() && !def.variants.is_empty() {
+                    write!(&mut name, "::{}", def.variants[index].ident).unwrap();
+                }
+            }
+            if let (&ty::Generator(_, _, _), &Variants::Single { index }) =
+                (layout.ty.kind(), &layout.variants)
+            {
+                write!(&mut name, "::{}", ty::GeneratorSubsts::variant_name(index)).unwrap();
+            }
+            Some(name)
+        }
+        ty::Adt(..) => {
+            // If `Some` is returned then a named struct is created in LLVM. Name collisions are
+            // avoided by LLVM (with increasing suffixes). If rustc doesn't generate names then that
+            // can improve perf.
+            // FIXME(antoyo): I don't think that's true for libgccjit.
+            Some(String::new())
+        }
+        _ => None,
+    };
+
+    match layout.fields {
+        FieldsShape::Primitive | FieldsShape::Union(_) => {
+            let fill = cx.type_padding_filler(layout.size, layout.align.abi);
+            let packed = false;
+            match name {
+                None => cx.type_struct(&[fill], packed),
+                Some(ref name) => {
+                    let gcc_type = cx.type_named_struct(name);
+                    cx.set_struct_body(gcc_type, &[fill], packed);
+                    gcc_type.as_type()
+                },
+            }
+        }
+        FieldsShape::Array { count, .. } => cx.type_array(layout.field(cx, 0).gcc_type(cx, true), count),
+        FieldsShape::Arbitrary { .. } =>
+            match name {
+                None => {
+                    let (gcc_fields, packed) = struct_fields(cx, layout);
+                    cx.type_struct(&gcc_fields, packed)
+                },
+                Some(ref name) => {
+                    let gcc_type = cx.type_named_struct(name);
+                    *defer = Some((gcc_type, layout));
+                    gcc_type.as_type()
+                },
+            },
+    }
+}
+
+pub trait LayoutGccExt<'tcx> {
+    fn is_gcc_immediate(&self) -> bool;
+    fn is_gcc_scalar_pair(&self) -> bool;
+    fn gcc_type<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>, set_fields: bool) -> Type<'gcc>;
+    fn immediate_gcc_type<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>) -> Type<'gcc>;
+    fn scalar_gcc_type_at<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>, scalar: &abi::Scalar, offset: Size) -> Type<'gcc>;
+    fn scalar_pair_element_gcc_type<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>, index: usize, immediate: bool) -> Type<'gcc>;
+    fn gcc_field_index(&self, index: usize) -> u64;
+    fn pointee_info_at<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>, offset: Size) -> Option<PointeeInfo>;
+}
+
+impl<'tcx> LayoutGccExt<'tcx> for TyAndLayout<'tcx> {
+    fn is_gcc_immediate(&self) -> bool {
+        match self.abi {
+            Abi::Scalar(_) | Abi::Vector { .. } => true,
+            Abi::ScalarPair(..) => false,
+            Abi::Uninhabited | Abi::Aggregate { .. } => self.is_zst(),
+        }
+    }
+
+    fn is_gcc_scalar_pair(&self) -> bool {
+        match self.abi {
+            Abi::ScalarPair(..) => true,
+            Abi::Uninhabited | Abi::Scalar(_) | Abi::Vector { .. } | Abi::Aggregate { .. } => false,
+        }
+    }
+
+    /// Gets the GCC type corresponding to a Rust type, i.e., `rustc_middle::ty::Ty`.
+    /// The pointee type of the pointer in `PlaceRef` is always this type.
+    /// For sized types, it is also the right LLVM type for an `alloca`
+    /// containing a value of that type, and most immediates (except `bool`).
+    /// Unsized types, however, are represented by a "minimal unit", e.g.
+    /// `[T]` becomes `T`, while `str` and `Trait` turn into `i8` - this
+    /// is useful for indexing slices, as `&[T]`'s data pointer is `T*`.
+    /// If the type is an unsized struct, the regular layout is generated,
+    /// with the inner-most trailing unsized field using the "minimal unit"
+    /// of that field's type - this is useful for taking the address of
+    /// that field and ensuring the struct has the right alignment.
+    //TODO(antoyo): do we still need the set_fields parameter?
+    fn gcc_type<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>, set_fields: bool) -> Type<'gcc> {
+        if let Abi::Scalar(ref scalar) = self.abi {
+            // Use a different cache for scalars because pointers to DSTs
+            // can be either fat or thin (data pointers of fat pointers).
+            if let Some(&ty) = cx.scalar_types.borrow().get(&self.ty) {
+                return ty;
+            }
+            let ty =
+                match *self.ty.kind() {
+                    ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => {
+                        cx.type_ptr_to(cx.layout_of(ty).gcc_type(cx, set_fields))
+                    }
+                    ty::Adt(def, _) if def.is_box() => {
+                        cx.type_ptr_to(cx.layout_of(self.ty.boxed_ty()).gcc_type(cx, true))
+                    }
+                    ty::FnPtr(sig) => cx.fn_ptr_backend_type(&cx.fn_abi_of_fn_ptr(sig, ty::List::empty())),
+                    _ => self.scalar_gcc_type_at(cx, scalar, Size::ZERO),
+                };
+            cx.scalar_types.borrow_mut().insert(self.ty, ty);
+            return ty;
+        }
+
+        // Check the cache.
+        let variant_index =
+            match self.variants {
+                Variants::Single { index } => Some(index),
+                _ => None,
+            };
+        let cached_type = cx.types.borrow().get(&(self.ty, variant_index)).cloned();
+        if let Some(ty) = cached_type {
+            let type_to_set_fields = cx.types_with_fields_to_set.borrow_mut().remove(&ty);
+            if let Some((struct_type, layout)) = type_to_set_fields {
+                // Since we might be trying to generate a type containing another type which is not
+                // completely generated yet, we deferred setting the fields until now.
+                let (fields, packed) = struct_fields(cx, layout);
+                cx.set_struct_body(struct_type, &fields, packed);
+            }
+            return ty;
+        }
+
+        assert!(!self.ty.has_escaping_bound_vars(), "{:?} has escaping bound vars", self.ty);
+
+        // Make sure lifetimes are erased, to avoid generating distinct LLVM
+        // types for Rust types that only differ in the choice of lifetimes.
+        let normal_ty = cx.tcx.erase_regions(self.ty);
+
+        let mut defer = None;
+        let ty =
+            if self.ty != normal_ty {
+                let mut layout = cx.layout_of(normal_ty);
+                if let Some(v) = variant_index {
+                    layout = layout.for_variant(cx, v);
+                }
+                layout.gcc_type(cx, true)
+            }
+            else {
+                uncached_gcc_type(cx, *self, &mut defer)
+            };
+
+        cx.types.borrow_mut().insert((self.ty, variant_index), ty);
+
+        if let Some((ty, layout)) = defer {
+            let (fields, packed) = struct_fields(cx, layout);
+            cx.set_struct_body(ty, &fields, packed);
+        }
+
+        ty
+    }
+
+    fn immediate_gcc_type<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>) -> Type<'gcc> {
+        if let Abi::Scalar(ref scalar) = self.abi {
+            if scalar.is_bool() {
+                return cx.type_i1();
+            }
+        }
+        self.gcc_type(cx, true)
+    }
+
+    fn scalar_gcc_type_at<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>, scalar: &abi::Scalar, offset: Size) -> Type<'gcc> {
+        match scalar.value {
+            Int(i, true) => cx.type_from_integer(i),
+            Int(i, false) => cx.type_from_unsigned_integer(i),
+            F32 => cx.type_f32(),
+            F64 => cx.type_f64(),
+            Pointer => {
+                // If we know the alignment, pick something better than i8.
+                let pointee =
+                    if let Some(pointee) = self.pointee_info_at(cx, offset) {
+                        cx.type_pointee_for_align(pointee.align)
+                    }
+                    else {
+                        cx.type_i8()
+                    };
+                cx.type_ptr_to(pointee)
+            }
+        }
+    }
+
+    fn scalar_pair_element_gcc_type<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>, index: usize, immediate: bool) -> Type<'gcc> {
+        // TODO(antoyo): remove llvm hack:
+        // HACK(eddyb) special-case fat pointers until LLVM removes
+        // pointee types, to avoid bitcasting every `OperandRef::deref`.
+        match self.ty.kind() {
+            ty::Ref(..) | ty::RawPtr(_) => {
+                return self.field(cx, index).gcc_type(cx, true);
+            }
+            ty::Adt(def, _) if def.is_box() => {
+                let ptr_ty = cx.tcx.mk_mut_ptr(self.ty.boxed_ty());
+                return cx.layout_of(ptr_ty).scalar_pair_element_gcc_type(cx, index, immediate);
+            }
+            _ => {}
+        }
+
+        let (a, b) = match self.abi {
+            Abi::ScalarPair(ref a, ref b) => (a, b),
+            _ => bug!("TyAndLayout::scalar_pair_element_llty({:?}): not applicable", self),
+        };
+        let scalar = [a, b][index];
+
+        // Make sure to return the same type `immediate_gcc_type` would when
+        // dealing with an immediate pair.  This means that `(bool, bool)` is
+        // effectively represented as `{i8, i8}` in memory and two `i1`s as an
+        // immediate, just like `bool` is typically `i8` in memory and only `i1`
+        // when immediate.  We need to load/store `bool` as `i8` to avoid
+        // crippling LLVM optimizations or triggering other LLVM bugs with `i1`.
+        // TODO(antoyo): this bugs certainly don't happen in this case since the bool type is used instead of i1.
+        if scalar.is_bool() {
+            return cx.type_i1();
+        }
+
+        let offset =
+            if index == 0 {
+                Size::ZERO
+            }
+            else {
+                a.value.size(cx).align_to(b.value.align(cx).abi)
+            };
+        self.scalar_gcc_type_at(cx, scalar, offset)
+    }
+
+    fn gcc_field_index(&self, index: usize) -> u64 {
+        match self.abi {
+            Abi::Scalar(_) | Abi::ScalarPair(..) => {
+                bug!("TyAndLayout::gcc_field_index({:?}): not applicable", self)
+            }
+            _ => {}
+        }
+        match self.fields {
+            FieldsShape::Primitive | FieldsShape::Union(_) => {
+                bug!("TyAndLayout::gcc_field_index({:?}): not applicable", self)
+            }
+
+            FieldsShape::Array { .. } => index as u64,
+
+            FieldsShape::Arbitrary { .. } => 1 + (self.fields.memory_index(index) as u64) * 2,
+        }
+    }
+
+    fn pointee_info_at<'a>(&self, cx: &CodegenCx<'a, 'tcx>, offset: Size) -> Option<PointeeInfo> {
+        if let Some(&pointee) = cx.pointee_infos.borrow().get(&(self.ty, offset)) {
+            return pointee;
+        }
+
+        let result = Ty::ty_and_layout_pointee_info_at(*self, cx, offset);
+
+        cx.pointee_infos.borrow_mut().insert((self.ty, offset), result);
+        result
+    }
+}
+
+impl<'gcc, 'tcx> LayoutTypeMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
+    fn backend_type(&self, layout: TyAndLayout<'tcx>) -> Type<'gcc> {
+        layout.gcc_type(self, true)
+    }
+
+    fn immediate_backend_type(&self, layout: TyAndLayout<'tcx>) -> Type<'gcc> {
+        layout.immediate_gcc_type(self)
+    }
+
+    fn is_backend_immediate(&self, layout: TyAndLayout<'tcx>) -> bool {
+        layout.is_gcc_immediate()
+    }
+
+    fn is_backend_scalar_pair(&self, layout: TyAndLayout<'tcx>) -> bool {
+        layout.is_gcc_scalar_pair()
+    }
+
+    fn backend_field_index(&self, layout: TyAndLayout<'tcx>, index: usize) -> u64 {
+        layout.gcc_field_index(index)
+    }
+
+    fn scalar_pair_element_backend_type(&self, layout: TyAndLayout<'tcx>, index: usize, immediate: bool) -> Type<'gcc> {
+        layout.scalar_pair_element_gcc_type(self, index, immediate)
+    }
+
+    fn cast_backend_type(&self, ty: &CastTarget) -> Type<'gcc> {
+        ty.gcc_type(self)
+    }
+
+    fn fn_ptr_backend_type(&self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> Type<'gcc> {
+        fn_abi.ptr_to_gcc_type(self)
+    }
+
+    fn reg_backend_type(&self, _ty: &Reg) -> Type<'gcc> {
+        unimplemented!();
+    }
+
+    fn fn_decl_backend_type(&self, _fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> Type<'gcc> {
+        // FIXME(antoyo): return correct type.
+        self.type_void()
+    }
+}