diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs new file mode 100644 index 000000000..73e01d045 --- /dev/null +++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs @@ -0,0 +1,437 @@ +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::vec::IndexVec; +use rustc_middle::{ + bug, + mir::{Field, GeneratorLayout, GeneratorSavedLocal}, + ty::{ + self, + layout::{IntegerExt, LayoutOf, PrimitiveExt, TyAndLayout}, + util::Discr, + AdtDef, GeneratorSubsts, Ty, VariantDef, + }, +}; +use rustc_span::Symbol; +use rustc_target::abi::{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), + &mut enum_adt_def.discriminants(cx.tcx).map(|(variant_index, discr)| { + (discr, Cow::from(enum_adt_def.variant(variant_index).name.as_str())) + }), + 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, + 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). +/// +// NOTE: Handling of discriminant values is somewhat inconsistent. They can appear as u128, +// u64, and i64. Here everything gets mapped to i64 because that's what LLVM's API expects. +fn build_enumeration_type_di_node<'ll, 'tcx>( + cx: &CodegenCx<'ll, 'tcx>, + type_name: &str, + base_type: Ty<'tcx>, + variants: &mut dyn Iterator<Item = (Discr<'tcx>, Cow<'tcx, str>)>, + 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 enumerator_di_nodes: SmallVec<Option<&'ll DIType>> = variants + .map(|(discr, variant_name)| { + unsafe { + Some(llvm::LLVMRustDIBuilderCreateEnumerator( + DIB(cx), + variant_name.as_ptr().cast(), + variant_name.len(), + // FIXME: what if enumeration has i128 discriminant? + discr.val as i64, + is_unsigned, + )) + } + }) + .collect(); + + let (size, align) = cx.size_and_align_of(base_type); + + 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: Ty<'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); + + type_map::build_type_with_children( + cx, + type_map::stub( + cx, + Stub::Struct, + UniqueTypeId::for_enum_variant_struct_type(cx.tcx, enum_type, variant_index), + variant_def.name.as_str(), + // NOTE: We use size and align of enum_type, not from variant_layout: + cx.size_and_align_of(enum_type), + 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 != CtorKind::Fn { + // Fields have names + Cow::from(variant_def.fields[field_index].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() + }, + |cx| build_generic_type_param_di_nodes(cx, enum_type), + ) + .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>, + state_specific_upvar_names: &IndexVec<GeneratorSavedLocal, Option<Symbol>>, + common_upvar_names: &[String], +) -> &'ll DIType { + let variant_name = GeneratorSubsts::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_substs = match generator_type_and_layout.ty.kind() { + ty::Generator(_, substs, _) => substs.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] + [Field::from_usize(field_index)]; + let field_name_maybe = state_specific_upvar_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_substs + .prefix_tys() + .enumerate() + .map(|(index, upvar_ty)| { + build_field_di_node( + cx, + variant_struct_type_di_node, + &common_upvar_names[index], + 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 +} + +/// 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 dataful 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, +) -> Option<u64> { + match enum_type_and_layout.layout.variants() { + &Variants::Single { .. } => None, + &Variants::Multiple { tag_encoding: TagEncoding::Direct, .. } => Some( + enum_type_and_layout.ty.discriminant_for_variant(cx.tcx, variant_index).unwrap().val + as u64, + ), + &Variants::Multiple { + tag_encoding: TagEncoding::Niche { ref niche_variants, niche_start, dataful_variant }, + tag, + .. + } => { + if variant_index == dataful_variant { + None + } 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); + // NOTE(eddyb) do *NOT* remove this assert, until + // we pass the full 128-bit value to LLVM, otherwise + // truncation will be silent and remain undetected. + assert_eq!(value as u64 as u128, value); + Some(value as u64) + } + } + } +} |