bjoernager/rust
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debuginfo: Change C++-like encoding for enums.

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The updated encoding should be able to handle niche layouts where
more than one variant has fields.
This commit is contained in:
Michael Woerister 2022-06-20 17:50:27 +02:00
parent e2b52ff73e
commit 622da5d834
15 changed files with 864 additions and 386 deletions
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52
compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
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@ -18,11 +18,10 @@ use rustc_hir::definitions::{DefPathData, DefPathDataName, DisambiguatedDefPathD
use rustc_hir::{AsyncGeneratorKind, GeneratorKind, Mutability};
use rustc_middle::ty::layout::{IntegerExt, TyAndLayout};
use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
use rustc_middle::ty::{self, ExistentialProjection, GeneratorSubsts, ParamEnv, Ty, TyCtxt};
use rustc_target::abi::{Integer, TagEncoding, Variants};
use rustc_middle::ty::{self, ExistentialProjection, ParamEnv, Ty, TyCtxt};
use rustc_target::abi::Integer;
use smallvec::SmallVec;
use std::borrow::Cow;
use std::fmt::Write;
use crate::debuginfo::wants_c_like_enum_debuginfo;
@ -98,7 +97,6 @@ fn push_debuginfo_type_name<'tcx>(
if let Some(ty_and_layout) = layout_for_cpp_like_fallback {
msvc_enum_fallback(
tcx,
ty_and_layout,
&|output, visited| {
push_item_name(tcx, def.did(), true, output);
@ -395,7 +393,6 @@ fn push_debuginfo_type_name<'tcx>(
if cpp_like_debuginfo && t.is_generator() {
let ty_and_layout = tcx.layout_of(ParamEnv::reveal_all().and(t)).unwrap();
msvc_enum_fallback(
tcx,
ty_and_layout,
&|output, visited| {
push_closure_or_generator_name(tcx, def_id, substs, true, output, visited);
@ -428,58 +425,17 @@ fn push_debuginfo_type_name<'tcx>(
/// MSVC names enums differently than other platforms so that the debugging visualization
// format (natvis) is able to understand enums and render the active variant correctly in the
// debugger. For more information, look in `src/etc/natvis/intrinsic.natvis` and
// `EnumMemberDescriptionFactor::create_member_descriptions`.
// debugger. For more information, look in
// rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs.
fn msvc_enum_fallback<'tcx>(
tcx: TyCtxt<'tcx>,
ty_and_layout: TyAndLayout<'tcx>,
push_inner: &dyn Fn(/*output*/ &mut String, /*visited*/ &mut FxHashSet<Ty<'tcx>>),
output: &mut String,
visited: &mut FxHashSet<Ty<'tcx>>,
) {
debug_assert!(!wants_c_like_enum_debuginfo(ty_and_layout));
let ty = ty_and_layout.ty;
output.push_str("enum$<");
push_inner(output, visited);
let variant_name = |variant_index| match ty.kind() {
ty::Adt(adt_def, _) => {
debug_assert!(adt_def.is_enum());
Cow::from(adt_def.variant(variant_index).name.as_str())
}
ty::Generator(..) => GeneratorSubsts::variant_name(variant_index),
_ => unreachable!(),
};
if let Variants::Multiple {
tag_encoding: TagEncoding::Niche { dataful_variant, .. },
tag,
variants,
..
} = &ty_and_layout.variants
{
let dataful_variant_layout = &variants[*dataful_variant];
// calculate the range of values for the dataful variant
let dataful_discriminant_range =
dataful_variant_layout.largest_niche().unwrap().valid_range;
let min = dataful_discriminant_range.start;
let min = tag.size(&tcx).truncate(min);
let max = dataful_discriminant_range.end;
let max = tag.size(&tcx).truncate(max);
let dataful_variant_name = variant_name(*dataful_variant);
write!(output, ", {}, {}, {}", min, max, dataful_variant_name).unwrap();
} else if let Variants::Single { index: variant_idx } = &ty_and_layout.variants {
// Uninhabited enums can't be constructed and should never need to be visualized so
// skip this step for them.
if !ty_and_layout.abi.is_uninhabited() {
write!(output, ", {}", variant_name(*variant_idx)).unwrap();
}
}
push_close_angle_bracket(true, output);
}