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use rustc_codegen_ssa::debuginfo::{
type_names::{compute_debuginfo_type_name, cpp_like_debuginfo},
wants_c_like_enum_debuginfo,
};
use rustc_hir::def::CtorKind;
use rustc_index::IndexSlice;
use rustc_middle::{
bug,
mir::GeneratorLayout,
ty::{
self,
layout::{IntegerExt, LayoutOf, PrimitiveExt, TyAndLayout},
AdtDef, GeneratorArgs, Ty, VariantDef,
},
};
use rustc_span::Symbol;
use rustc_target::abi::{
FieldIdx, HasDataLayout, Integer, Primitive, TagEncoding, VariantIdx, Variants,
};
use std::borrow::Cow;
use crate::{
common::CodegenCx,
debuginfo::{
metadata::{
build_field_di_node, build_generic_type_param_di_nodes, type_di_node,
type_map::{self, Stub},
unknown_file_metadata, UNKNOWN_LINE_NUMBER,
},
utils::{create_DIArray, get_namespace_for_item, DIB},
},
llvm::{
self,
debuginfo::{DIFlags, DIType},
},
};
use super::{
size_and_align_of,
type_map::{DINodeCreationResult, UniqueTypeId},
SmallVec,
};
mod cpp_like;
mod native;
pub(super) fn build_enum_type_di_node<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
unique_type_id: UniqueTypeId<'tcx>,
) -> DINodeCreationResult<'ll> {
let enum_type = unique_type_id.expect_ty();
let &ty::Adt(enum_adt_def, _) = enum_type.kind() else {
bug!("build_enum_type_di_node() called with non-enum type: `{:?}`", enum_type)
};
let enum_type_and_layout = cx.layout_of(enum_type);
if wants_c_like_enum_debuginfo(enum_type_and_layout) {
return build_c_style_enum_di_node(cx, enum_adt_def, enum_type_and_layout);
}
if cpp_like_debuginfo(cx.tcx) {
cpp_like::build_enum_type_di_node(cx, unique_type_id)
} else {
native::build_enum_type_di_node(cx, unique_type_id)
}
}
pub(super) fn build_generator_di_node<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
unique_type_id: UniqueTypeId<'tcx>,
) -> DINodeCreationResult<'ll> {
if cpp_like_debuginfo(cx.tcx) {
cpp_like::build_generator_di_node(cx, unique_type_id)
} else {
native::build_generator_di_node(cx, unique_type_id)
}
}
/// Build the debuginfo node for a C-style enum, i.e. an enum the variants of which have no fields.
///
/// The resulting debuginfo will be a DW_TAG_enumeration_type.
fn build_c_style_enum_di_node<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
enum_adt_def: AdtDef<'tcx>,
enum_type_and_layout: TyAndLayout<'tcx>,
) -> DINodeCreationResult<'ll> {
let containing_scope = get_namespace_for_item(cx, enum_adt_def.did());
DINodeCreationResult {
di_node: build_enumeration_type_di_node(
cx,
&compute_debuginfo_type_name(cx.tcx, enum_type_and_layout.ty, false),
tag_base_type(cx, enum_type_and_layout),
enum_adt_def.discriminants(cx.tcx).map(|(variant_index, discr)| {
let name = Cow::from(enum_adt_def.variant(variant_index).name.as_str());
(name, discr.val)
}),
containing_scope,
),
already_stored_in_typemap: false,
}
}
/// Extract the type with which we want to describe the tag of the given enum or generator.
fn tag_base_type<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
enum_type_and_layout: TyAndLayout<'tcx>,
) -> Ty<'tcx> {
debug_assert!(match enum_type_and_layout.ty.kind() {
ty::Generator(..) => true,
ty::Adt(adt_def, _) => adt_def.is_enum(),
_ => false,
});
match enum_type_and_layout.layout.variants() {
// A single-variant enum has no discriminant.
Variants::Single { .. } => {
bug!("tag_base_type() called for enum without tag: {:?}", enum_type_and_layout)
}
Variants::Multiple { tag_encoding: TagEncoding::Niche { .. }, tag, .. } => {
// Niche tags are always normalized to unsized integers of the correct size.
match tag.primitive() {
Primitive::Int(t, _) => t,
Primitive::F32 => Integer::I32,
Primitive::F64 => Integer::I64,
// FIXME(erikdesjardins): handle non-default addrspace ptr sizes
Primitive::Pointer(_) => {
// If the niche is the NULL value of a reference, then `discr_enum_ty` will be
// a RawPtr. CodeView doesn't know what to do with enums whose base type is a
// pointer so we fix this up to just be `usize`.
// DWARF might be able to deal with this but with an integer type we are on
// the safe side there too.
cx.data_layout().ptr_sized_integer()
}
}
.to_ty(cx.tcx, false)
}
Variants::Multiple { tag_encoding: TagEncoding::Direct, tag, .. } => {
// Direct tags preserve the sign.
tag.primitive().to_ty(cx.tcx)
}
}
}
/// Build a DW_TAG_enumeration_type debuginfo node, with the given base type and variants.
/// This is a helper function and does not register anything in the type map by itself.
///
/// `variants` is an iterator of (discr-value, variant-name).
fn build_enumeration_type_di_node<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
type_name: &str,
base_type: Ty<'tcx>,
enumerators: impl Iterator<Item = (Cow<'tcx, str>, u128)>,
containing_scope: &'ll DIType,
) -> &'ll DIType {
let is_unsigned = match base_type.kind() {
ty::Int(_) => false,
ty::Uint(_) => true,
_ => bug!("build_enumeration_type_di_node() called with non-integer tag type."),
};
let (size, align) = cx.size_and_align_of(base_type);
let enumerator_di_nodes: SmallVec<Option<&'ll DIType>> = enumerators
.map(|(name, value)| unsafe {
let value = [value as u64, (value >> 64) as u64];
Some(llvm::LLVMRustDIBuilderCreateEnumerator(
DIB(cx),
name.as_ptr().cast(),
name.len(),
value.as_ptr(),
size.bits() as libc::c_uint,
is_unsigned,
))
})
.collect();
unsafe {
llvm::LLVMRustDIBuilderCreateEnumerationType(
DIB(cx),
containing_scope,
type_name.as_ptr().cast(),
type_name.len(),
unknown_file_metadata(cx),
UNKNOWN_LINE_NUMBER,
size.bits(),
align.bits() as u32,
create_DIArray(DIB(cx), &enumerator_di_nodes[..]),
type_di_node(cx, base_type),
true,
)
}
}
/// Build the debuginfo node for the struct type describing a single variant of an enum.
///
/// ```txt
/// DW_TAG_structure_type (top-level type for enum)
/// DW_TAG_variant_part (variant part)
/// DW_AT_discr (reference to discriminant DW_TAG_member)
/// DW_TAG_member (discriminant member)
/// DW_TAG_variant (variant 1)
/// DW_TAG_variant (variant 2)
/// DW_TAG_variant (variant 3)
/// ---> DW_TAG_structure_type (type of variant 1)
/// ---> DW_TAG_structure_type (type of variant 2)
/// ---> DW_TAG_structure_type (type of variant 3)
/// ```
///
/// In CPP-like mode, we have the exact same descriptions for each variant too:
///
/// ```txt
/// DW_TAG_union_type (top-level type for enum)
/// DW_TAG_member (member for variant 1)
/// DW_TAG_member (member for variant 2)
/// DW_TAG_member (member for variant 3)
/// ---> DW_TAG_structure_type (type of variant 1)
/// ---> DW_TAG_structure_type (type of variant 2)
/// ---> DW_TAG_structure_type (type of variant 3)
/// DW_TAG_enumeration_type (type of tag)
/// ```
///
/// The node looks like:
///
/// ```txt
/// DW_TAG_structure_type
/// DW_AT_name <name-of-variant>
/// DW_AT_byte_size 0x00000010
/// DW_AT_alignment 0x00000008
/// DW_TAG_member
/// DW_AT_name <name-of-field-0>
/// DW_AT_type <0x0000018e>
/// DW_AT_alignment 0x00000004
/// DW_AT_data_member_location 4
/// DW_TAG_member
/// DW_AT_name <name-of-field-1>
/// DW_AT_type <0x00000195>
/// DW_AT_alignment 0x00000008
/// DW_AT_data_member_location 8
/// ...
/// ```
///
/// The type of a variant is always a struct type with the name of the variant
/// and a DW_TAG_member for each field (but not the discriminant).
fn build_enum_variant_struct_type_di_node<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
enum_type_and_layout: TyAndLayout<'tcx>,
enum_type_di_node: &'ll DIType,
variant_index: VariantIdx,
variant_def: &VariantDef,
variant_layout: TyAndLayout<'tcx>,
) -> &'ll DIType {
debug_assert_eq!(variant_layout.ty, enum_type_and_layout.ty);
type_map::build_type_with_children(
cx,
type_map::stub(
cx,
Stub::Struct,
UniqueTypeId::for_enum_variant_struct_type(
cx.tcx,
enum_type_and_layout.ty,
variant_index,
),
variant_def.name.as_str(),
// NOTE: We use size and align of enum_type, not from variant_layout:
size_and_align_of(enum_type_and_layout),
Some(enum_type_di_node),
DIFlags::FlagZero,
),
|cx, struct_type_di_node| {
(0..variant_layout.fields.count())
.map(|field_index| {
let field_name = if variant_def.ctor_kind() != Some(CtorKind::Fn) {
// Fields have names
let field = &variant_def.fields[FieldIdx::from_usize(field_index)];
Cow::from(field.name.as_str())
} else {
// Tuple-like
super::tuple_field_name(field_index)
};
let field_layout = variant_layout.field(cx, field_index);
build_field_di_node(
cx,
struct_type_di_node,
&field_name,
(field_layout.size, field_layout.align.abi),
variant_layout.fields.offset(field_index),
DIFlags::FlagZero,
type_di_node(cx, field_layout.ty),
)
})
.collect::<SmallVec<_>>()
},
|cx| build_generic_type_param_di_nodes(cx, enum_type_and_layout.ty),
)
.di_node
}
/// Build the struct type for describing a single generator state.
/// See [build_generator_variant_struct_type_di_node].
///
/// ```txt
///
/// DW_TAG_structure_type (top-level type for enum)
/// DW_TAG_variant_part (variant part)
/// DW_AT_discr (reference to discriminant DW_TAG_member)
/// DW_TAG_member (discriminant member)
/// DW_TAG_variant (variant 1)
/// DW_TAG_variant (variant 2)
/// DW_TAG_variant (variant 3)
/// ---> DW_TAG_structure_type (type of variant 1)
/// ---> DW_TAG_structure_type (type of variant 2)
/// ---> DW_TAG_structure_type (type of variant 3)
///
/// ```
pub fn build_generator_variant_struct_type_di_node<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
variant_index: VariantIdx,
generator_type_and_layout: TyAndLayout<'tcx>,
generator_type_di_node: &'ll DIType,
generator_layout: &GeneratorLayout<'tcx>,
common_upvar_names: &IndexSlice<FieldIdx, Symbol>,
) -> &'ll DIType {
let variant_name = GeneratorArgs::variant_name(variant_index);
let unique_type_id = UniqueTypeId::for_enum_variant_struct_type(
cx.tcx,
generator_type_and_layout.ty,
variant_index,
);
let variant_layout = generator_type_and_layout.for_variant(cx, variant_index);
let generator_args = match generator_type_and_layout.ty.kind() {
ty::Generator(_, args, _) => args.as_generator(),
_ => unreachable!(),
};
type_map::build_type_with_children(
cx,
type_map::stub(
cx,
Stub::Struct,
unique_type_id,
&variant_name,
size_and_align_of(generator_type_and_layout),
Some(generator_type_di_node),
DIFlags::FlagZero,
),
|cx, variant_struct_type_di_node| {
// Fields that just belong to this variant/state
let state_specific_fields: SmallVec<_> = (0..variant_layout.fields.count())
.map(|field_index| {
let generator_saved_local = generator_layout.variant_fields[variant_index]
[FieldIdx::from_usize(field_index)];
let field_name_maybe = generator_layout.field_names[generator_saved_local];
let field_name = field_name_maybe
.as_ref()
.map(|s| Cow::from(s.as_str()))
.unwrap_or_else(|| super::tuple_field_name(field_index));
let field_type = variant_layout.field(cx, field_index).ty;
build_field_di_node(
cx,
variant_struct_type_di_node,
&field_name,
cx.size_and_align_of(field_type),
variant_layout.fields.offset(field_index),
DIFlags::FlagZero,
type_di_node(cx, field_type),
)
})
.collect();
// Fields that are common to all states
let common_fields: SmallVec<_> = generator_args
.prefix_tys()
.iter()
.zip(common_upvar_names)
.enumerate()
.map(|(index, (upvar_ty, upvar_name))| {
build_field_di_node(
cx,
variant_struct_type_di_node,
upvar_name.as_str(),
cx.size_and_align_of(upvar_ty),
generator_type_and_layout.fields.offset(index),
DIFlags::FlagZero,
type_di_node(cx, upvar_ty),
)
})
.collect();
state_specific_fields.into_iter().chain(common_fields.into_iter()).collect()
},
|cx| build_generic_type_param_di_nodes(cx, generator_type_and_layout.ty),
)
.di_node
}
#[derive(Copy, Clone)]
enum DiscrResult {
NoDiscriminant,
Value(u128),
Range(u128, u128),
}
impl DiscrResult {
fn opt_single_val(&self) -> Option<u128> {
if let Self::Value(d) = *self { Some(d) } else { None }
}
}
/// Returns the discriminant value corresponding to the variant index.
///
/// Will return `None` if there is less than two variants (because then the enum won't have)
/// a tag, and if this is the untagged variant of a niche-layout enum (because then there is no
/// single discriminant value).
fn compute_discriminant_value<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
enum_type_and_layout: TyAndLayout<'tcx>,
variant_index: VariantIdx,
) -> DiscrResult {
match enum_type_and_layout.layout.variants() {
&Variants::Single { .. } => DiscrResult::NoDiscriminant,
&Variants::Multiple { tag_encoding: TagEncoding::Direct, .. } => DiscrResult::Value(
enum_type_and_layout.ty.discriminant_for_variant(cx.tcx, variant_index).unwrap().val,
),
&Variants::Multiple {
tag_encoding: TagEncoding::Niche { ref niche_variants, niche_start, untagged_variant },
tag,
..
} => {
if variant_index == untagged_variant {
let valid_range = enum_type_and_layout
.for_variant(cx, variant_index)
.largest_niche
.as_ref()
.unwrap()
.valid_range;
let min = valid_range.start.min(valid_range.end);
let min = tag.size(cx).truncate(min);
let max = valid_range.start.max(valid_range.end);
let max = tag.size(cx).truncate(max);
DiscrResult::Range(min, max)
} else {
let value = (variant_index.as_u32() as u128)
.wrapping_sub(niche_variants.start().as_u32() as u128)
.wrapping_add(niche_start);
let value = tag.size(cx).truncate(value);
DiscrResult::Value(value)
}
}
}
}