diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/debuginfo')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs | 199 |
1 files changed, 127 insertions, 72 deletions
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs index af0d95a354b..1f268bd1878 100644 --- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs +++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs @@ -1594,77 +1594,144 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> { ref variants, tag_field, } => { + let calculate_niche_value = |i: VariantIdx| { + if i == dataful_variant { + None + } else { + let value = (i.as_u32() as u128) + .wrapping_sub(niche_variants.start().as_u32() as u128) + .wrapping_add(niche_start); + let value = tag.value.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) + } + }; + + // For MSVC, we will generate a union of two structs, one for the dataful variant and one that just points to + // the discriminant field. We also create an enum that contains tag values for the non-dataful variants and + // make the discriminant field that type. We then use natvis to render the enum type correctly in Windbg/VS. if fallback { - let variant = self.layout.for_variant(cx, dataful_variant); - // Create a description of the non-null variant. - let (variant_type_metadata, member_description_factory) = describe_enum_variant( + let unique_type_id = debug_context(cx) + .type_map + .borrow_mut() + .get_unique_type_id_of_enum_variant(cx, self.enum_type, "discriminant$"); + + let variant_metadata = create_struct_stub( + cx, + self.layout.ty, + &"discriminant$", + unique_type_id, + Some(self_metadata), + DIFlags::FlagArtificial, + ); + + let dataful_variant_layout = self.layout.for_variant(cx, dataful_variant); + + let mut discr_enum_ty = tag.value.to_ty(cx.tcx); + // 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`. + if let ty::RawPtr(_) = discr_enum_ty.kind() { + discr_enum_ty = cx.tcx.types.usize; + } + + let tags: Vec<_> = variants + .iter_enumerated() + .filter_map(|(variant_idx, _)| { + calculate_niche_value(variant_idx).map(|tag| { + let variant = variant_info_for(variant_idx); + let name = variant.variant_name(); + + Some(unsafe { + llvm::LLVMRustDIBuilderCreateEnumerator( + DIB(cx), + name.as_ptr().cast(), + name.len(), + tag as i64, + !discr_enum_ty.is_signed(), + ) + }) + }) + }) + .collect(); + + let discr_enum = unsafe { + llvm::LLVMRustDIBuilderCreateEnumerationType( + DIB(cx), + self_metadata, + "tag$".as_ptr().cast(), + "tag$".len(), + unknown_file_metadata(cx), + UNKNOWN_LINE_NUMBER, + tag.value.size(cx).bits(), + tag.value.align(cx).abi.bits() as u32, + create_DIArray(DIB(cx), &tags), + type_metadata(cx, discr_enum_ty, self.span), + true, + ) + }; + + let (size, align) = + cx.size_and_align_of(dataful_variant_layout.field(cx, tag_field).ty); + let members = vec![MemberDescription { + name: "discriminant".to_string(), + type_metadata: discr_enum, + offset: dataful_variant_layout.fields.offset(tag_field), + size, + align, + flags: DIFlags::FlagArtificial, + discriminant: None, + source_info: None, + }]; + + set_members_of_composite_type(cx, self.enum_type, variant_metadata, members, None); + + let variant_info = variant_info_for(dataful_variant); + let (variant_type_metadata, member_desc_factory) = describe_enum_variant( cx, - variant, - variant_info_for(dataful_variant), + dataful_variant_layout, + variant_info, Some(NicheTag), self_metadata, self.span, ); - let variant_member_descriptions = - member_description_factory.create_member_descriptions(cx); + let member_descriptions = member_desc_factory.create_member_descriptions(cx); set_members_of_composite_type( cx, self.enum_type, variant_type_metadata, - variant_member_descriptions, + member_descriptions, Some(&self.common_members), ); - // Encode the information about the null variant in the union - // member's name. - let mut name = String::from("RUST$ENCODED$ENUM$"); - // Right now it's not even going to work for `niche_start > 0`, - // and for multiple niche variants it only supports the first. - fn compute_field_path<'a, 'tcx>( - cx: &CodegenCx<'a, 'tcx>, - name: &mut String, - layout: TyAndLayout<'tcx>, - offset: Size, - size: Size, - ) { - for i in 0..layout.fields.count() { - let field_offset = layout.fields.offset(i); - if field_offset > offset { - continue; - } - let inner_offset = offset - field_offset; - let field = layout.field(cx, i); - if inner_offset + size <= field.size { - write!(name, "{}$", i).unwrap(); - compute_field_path(cx, name, field, inner_offset, size); - } - } - } - compute_field_path( - cx, - &mut name, - self.layout, - self.layout.fields.offset(tag_field), - self.layout.field(cx, tag_field).size, - ); - let variant_info = variant_info_for(*niche_variants.start()); - variant_info.map_struct_name(|variant_name| { - name.push_str(variant_name); - }); - - // Create the (singleton) list of descriptions of union members. - vec![MemberDescription { - name, - type_metadata: variant_type_metadata, - offset: Size::ZERO, - size: variant.size, - align: variant.align.abi, - flags: DIFlags::FlagZero, - discriminant: None, - source_info: variant_info.source_info(cx), - }] + vec![ + MemberDescription { + // Name the dataful variant so that we can identify it for natvis + name: "dataful_variant".to_string(), + type_metadata: variant_type_metadata, + offset: Size::ZERO, + size: self.layout.size, + align: self.layout.align.abi, + flags: DIFlags::FlagZero, + discriminant: None, + source_info: variant_info.source_info(cx), + }, + MemberDescription { + name: "discriminant$".into(), + type_metadata: variant_metadata, + offset: Size::ZERO, + size: self.layout.size, + align: self.layout.align.abi, + flags: DIFlags::FlagZero, + discriminant: None, + source_info: None, + }, + ] } else { variants .iter_enumerated() @@ -1692,19 +1759,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> { Some(&self.common_members), ); - let niche_value = if i == dataful_variant { - None - } else { - let value = (i.as_u32() as u128) - .wrapping_sub(niche_variants.start().as_u32() as u128) - .wrapping_add(niche_start); - let value = tag.value.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) - }; + let niche_value = calculate_niche_value(i); MemberDescription { name: variant_info.variant_name(), @@ -2040,9 +2095,9 @@ fn prepare_enum_metadata( if use_enum_fallback(cx) { let discriminant_type_metadata = match layout.variants { - Variants::Single { .. } - | Variants::Multiple { tag_encoding: TagEncoding::Niche { .. }, .. } => None, - Variants::Multiple { tag_encoding: TagEncoding::Direct, ref tag, .. } => { + Variants::Single { .. } => None, + Variants::Multiple { tag_encoding: TagEncoding::Niche { .. }, ref tag, .. } + | Variants::Multiple { tag_encoding: TagEncoding::Direct, ref tag, .. } => { Some(discriminant_type_metadata(tag.value)) } }; 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