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Auto merge of rust-lang#128037 - beetrees:repr128-c-style-use-natvis,…
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… r=michaelwoerister

Use the `enum2$` Natvis visualiser for repr128 C-style enums

Use the preexisting `enum2$` Natvis visualiser to allow PDB debuggers to display fieldless `#[repr(u128)]]`/`#[repr(i128)]]` enums correctly.

Tracking issue: rust-lang#56071

try-job: x86_64-msvc
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bors committed Aug 15, 2024
2 parents 13a5289 + fe4fa2f commit de8a09a
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Showing 6 changed files with 136 additions and 67 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ use std::borrow::Cow;

use libc::c_uint;
use rustc_codegen_ssa::debuginfo::type_names::compute_debuginfo_type_name;
use rustc_codegen_ssa::debuginfo::wants_c_like_enum_debuginfo;
use rustc_codegen_ssa::debuginfo::{tag_base_type, wants_c_like_enum_debuginfo};
use rustc_codegen_ssa::traits::ConstMethods;
use rustc_index::IndexVec;
use rustc_middle::bug;
Expand All @@ -12,7 +12,7 @@ use rustc_target::abi::{Align, Endian, Size, TagEncoding, VariantIdx, Variants};
use smallvec::smallvec;

use crate::common::CodegenCx;
use crate::debuginfo::metadata::enums::{tag_base_type, DiscrResult};
use crate::debuginfo::metadata::enums::DiscrResult;
use crate::debuginfo::metadata::type_map::{self, Stub, UniqueTypeId};
use crate::debuginfo::metadata::{
build_field_di_node, file_metadata, size_and_align_of, type_di_node, unknown_file_metadata,
Expand Down Expand Up @@ -190,7 +190,7 @@ pub(super) fn build_enum_type_di_node<'ll, 'tcx>(
let enum_type_and_layout = cx.layout_of(enum_type);
let enum_type_name = compute_debuginfo_type_name(cx.tcx, enum_type, false);

assert!(!wants_c_like_enum_debuginfo(enum_type_and_layout));
assert!(!wants_c_like_enum_debuginfo(cx.tcx, enum_type_and_layout));

type_map::build_type_with_children(
cx,
Expand Down Expand Up @@ -265,7 +265,7 @@ pub(super) fn build_coroutine_di_node<'ll, 'tcx>(
let coroutine_type_and_layout = cx.layout_of(coroutine_type);
let coroutine_type_name = compute_debuginfo_type_name(cx.tcx, coroutine_type, false);

assert!(!wants_c_like_enum_debuginfo(coroutine_type_and_layout));
assert!(!wants_c_like_enum_debuginfo(cx.tcx, coroutine_type_and_layout));

type_map::build_type_with_children(
cx,
Expand Down Expand Up @@ -381,7 +381,7 @@ fn build_union_fields_for_enum<'ll, 'tcx>(
tag_field: usize,
untagged_variant_index: Option<VariantIdx>,
) -> SmallVec<&'ll DIType> {
let tag_base_type = super::tag_base_type(cx, enum_type_and_layout);
let tag_base_type = tag_base_type(cx.tcx, enum_type_and_layout);

let variant_names_type_di_node = build_variant_names_type_di_node(
cx,
Expand Down Expand Up @@ -676,7 +676,7 @@ fn build_union_fields_for_direct_tag_coroutine<'ll, 'tcx>(
let variant_range = coroutine_args.variant_range(coroutine_def_id, cx.tcx);
let variant_count = (variant_range.start.as_u32()..variant_range.end.as_u32()).len();

let tag_base_type = tag_base_type(cx, coroutine_type_and_layout);
let tag_base_type = tag_base_type(cx.tcx, coroutine_type_and_layout);

let variant_names_type_di_node = build_variant_names_type_di_node(
cx,
Expand Down Expand Up @@ -803,7 +803,7 @@ fn build_union_fields_for_direct_tag_enum_or_coroutine<'ll, 'tcx>(

assert_eq!(
cx.size_and_align_of(enum_type_and_layout.field(cx, tag_field).ty),
cx.size_and_align_of(super::tag_base_type(cx, enum_type_and_layout))
cx.size_and_align_of(self::tag_base_type(cx.tcx, enum_type_and_layout))
);

// ... and a field for the tag. If the tag is 128 bits wide, this will actually
Expand Down
54 changes: 5 additions & 49 deletions compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
Original file line number Diff line number Diff line change
@@ -1,17 +1,15 @@
use std::borrow::Cow;

use rustc_codegen_ssa::debuginfo::type_names::{compute_debuginfo_type_name, cpp_like_debuginfo};
use rustc_codegen_ssa::debuginfo::wants_c_like_enum_debuginfo;
use rustc_codegen_ssa::debuginfo::{tag_base_type, wants_c_like_enum_debuginfo};
use rustc_hir::def::CtorKind;
use rustc_index::IndexSlice;
use rustc_middle::bug;
use rustc_middle::mir::CoroutineLayout;
use rustc_middle::ty::layout::{IntegerExt, LayoutOf, PrimitiveExt, TyAndLayout};
use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
use rustc_middle::ty::{self, AdtDef, CoroutineArgs, CoroutineArgsExt, Ty, VariantDef};
use rustc_span::Symbol;
use rustc_target::abi::{
FieldIdx, HasDataLayout, Integer, Primitive, TagEncoding, VariantIdx, Variants,
};
use rustc_target::abi::{FieldIdx, TagEncoding, VariantIdx, Variants};

use super::type_map::{DINodeCreationResult, UniqueTypeId};
use super::{size_and_align_of, SmallVec};
Expand Down Expand Up @@ -39,7 +37,7 @@ pub(super) fn build_enum_type_di_node<'ll, 'tcx>(

let enum_type_and_layout = cx.layout_of(enum_type);

if wants_c_like_enum_debuginfo(enum_type_and_layout) {
if wants_c_like_enum_debuginfo(cx.tcx, enum_type_and_layout) {
return build_c_style_enum_di_node(cx, enum_adt_def, enum_type_and_layout);
}

Expand Down Expand Up @@ -74,7 +72,7 @@ fn build_c_style_enum_di_node<'ll, 'tcx>(
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),
tag_base_type(cx.tcx, 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)
Expand All @@ -85,48 +83,6 @@ fn build_c_style_enum_di_node<'ll, 'tcx>(
}
}

/// Extract the type with which we want to describe the tag of the given enum or coroutine.
fn tag_base_type<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
enum_type_and_layout: TyAndLayout<'tcx>,
) -> Ty<'tcx> {
assert!(match enum_type_and_layout.ty.kind() {
ty::Coroutine(..) => 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::Float(f) => Integer::from_size(f.size()).unwrap(),
// 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.
///
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ use std::borrow::Cow;

use libc::c_uint;
use rustc_codegen_ssa::debuginfo::type_names::compute_debuginfo_type_name;
use rustc_codegen_ssa::debuginfo::wants_c_like_enum_debuginfo;
use rustc_codegen_ssa::debuginfo::{tag_base_type, wants_c_like_enum_debuginfo};
use rustc_codegen_ssa::traits::ConstMethods;
use rustc_middle::bug;
use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
Expand All @@ -11,7 +11,6 @@ use rustc_target::abi::{Size, TagEncoding, VariantIdx, Variants};
use smallvec::smallvec;

use crate::common::CodegenCx;
use crate::debuginfo::metadata::enums::tag_base_type;
use crate::debuginfo::metadata::type_map::{self, Stub, StubInfo, UniqueTypeId};
use crate::debuginfo::metadata::{
file_metadata, size_and_align_of, type_di_node, unknown_file_metadata, visibility_di_flags,
Expand Down Expand Up @@ -54,7 +53,7 @@ pub(super) fn build_enum_type_di_node<'ll, 'tcx>(

let visibility_flags = visibility_di_flags(cx, enum_adt_def.did(), enum_adt_def.did());

assert!(!wants_c_like_enum_debuginfo(enum_type_and_layout));
assert!(!wants_c_like_enum_debuginfo(cx.tcx, enum_type_and_layout));

type_map::build_type_with_children(
cx,
Expand Down Expand Up @@ -131,7 +130,7 @@ pub(super) fn build_coroutine_di_node<'ll, 'tcx>(
let containing_scope = get_namespace_for_item(cx, coroutine_def_id);
let coroutine_type_and_layout = cx.layout_of(coroutine_type);

assert!(!wants_c_like_enum_debuginfo(coroutine_type_and_layout));
assert!(!wants_c_like_enum_debuginfo(cx.tcx, coroutine_type_and_layout));

let coroutine_type_name = compute_debuginfo_type_name(cx.tcx, coroutine_type, false);

Expand Down Expand Up @@ -321,7 +320,7 @@ fn build_discr_member_di_node<'ll, 'tcx>(
&Variants::Single { .. } => None,

&Variants::Multiple { tag_field, .. } => {
let tag_base_type = tag_base_type(cx, enum_or_coroutine_type_and_layout);
let tag_base_type = tag_base_type(cx.tcx, enum_or_coroutine_type_and_layout);
let (size, align) = cx.size_and_align_of(tag_base_type);

unsafe {
Expand Down
69 changes: 65 additions & 4 deletions compiler/rustc_codegen_ssa/src/debuginfo/mod.rs
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
use rustc_middle::ty::layout::TyAndLayout;
use rustc_middle::ty::{self};
use rustc_target::abi::Size;
use rustc_middle::bug;
use rustc_middle::ty::layout::{IntegerExt, PrimitiveExt, TyAndLayout};
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_target::abi::{Integer, Primitive, Size, TagEncoding, Variants};

// FIXME(eddyb) find a place for this (or a way to replace it).
pub mod type_names;
Expand All @@ -11,13 +12,25 @@ pub mod type_names;
/// NOTE: This is somewhat inconsistent right now: For empty enums and enums with a single
/// fieldless variant, we generate DW_TAG_struct_type, although a
/// DW_TAG_enumeration_type would be a better fit.
pub fn wants_c_like_enum_debuginfo(enum_type_and_layout: TyAndLayout<'_>) -> bool {
pub fn wants_c_like_enum_debuginfo<'tcx>(
tcx: TyCtxt<'tcx>,
enum_type_and_layout: TyAndLayout<'tcx>,
) -> bool {
match enum_type_and_layout.ty.kind() {
ty::Adt(adt_def, _) => {
if !adt_def.is_enum() {
return false;
}

if type_names::cpp_like_debuginfo(tcx)
&& tag_base_type_opt(tcx, enum_type_and_layout)
.map(|ty| ty.primitive_size(tcx).bits())
== Some(128)
{
// C++-like debuginfo never uses the C-like representation for 128-bit enums.
return false;
}

match adt_def.variants().len() {
0 => false,
1 => {
Expand All @@ -33,3 +46,51 @@ pub fn wants_c_like_enum_debuginfo(enum_type_and_layout: TyAndLayout<'_>) -> boo
_ => false,
}
}

/// Extract the type with which we want to describe the tag of the given enum or coroutine.
pub fn tag_base_type<'tcx>(tcx: TyCtxt<'tcx>, enum_type_and_layout: TyAndLayout<'tcx>) -> Ty<'tcx> {
tag_base_type_opt(tcx, enum_type_and_layout).unwrap_or_else(|| {
bug!("tag_base_type() called for enum without tag: {:?}", enum_type_and_layout)
})
}

pub fn tag_base_type_opt<'tcx>(
tcx: TyCtxt<'tcx>,
enum_type_and_layout: TyAndLayout<'tcx>,
) -> Option<Ty<'tcx>> {
assert!(match enum_type_and_layout.ty.kind() {
ty::Coroutine(..) => 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 { .. } => None,

Variants::Multiple { tag_encoding: TagEncoding::Niche { .. }, tag, .. } => {
// Niche tags are always normalized to unsized integers of the correct size.
Some(
match tag.primitive() {
Primitive::Int(t, _) => t,
Primitive::Float(f) => Integer::from_size(f.size()).unwrap(),
// 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.
tcx.data_layout.ptr_sized_integer()
}
}
.to_ty(tcx, false),
)
}

Variants::Multiple { tag_encoding: TagEncoding::Direct, tag, .. } => {
// Direct tags preserve the sign.
Some(tag.primitive().to_ty(tcx))
}
}
}
7 changes: 5 additions & 2 deletions compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,7 @@ fn push_debuginfo_type_name<'tcx>(
let layout_for_cpp_like_fallback = if cpp_like_debuginfo && def.is_enum() {
match tcx.layout_of(ParamEnv::reveal_all().and(t)) {
Ok(layout) => {
if !wants_c_like_enum_debuginfo(layout) {
if !wants_c_like_enum_debuginfo(tcx, layout) {
Some(layout)
} else {
// This is a C-like enum so we don't want to use the fallback encoding
Expand All @@ -106,6 +106,7 @@ 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);
Expand Down Expand Up @@ -421,6 +422,7 @@ fn push_debuginfo_type_name<'tcx>(
if cpp_like_debuginfo && t.is_coroutine() {
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_coroutine_name(tcx, def_id, args, true, output, visited);
Expand Down Expand Up @@ -455,12 +457,13 @@ fn push_debuginfo_type_name<'tcx>(
// 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>>,
) {
assert!(!wants_c_like_enum_debuginfo(ty_and_layout));
assert!(!wants_c_like_enum_debuginfo(tcx, ty_and_layout));
output.push_str("enum2$<");
push_inner(output, visited);
push_close_angle_bracket(true, output);
Expand Down
50 changes: 50 additions & 0 deletions tests/debuginfo/msvc-pretty-enums.rs
Original file line number Diff line number Diff line change
Expand Up @@ -206,6 +206,30 @@
// cdb-command: dx -r2 arbitrary_discr2,d
// cdb-check: arbitrary_discr2,d : Def [Type: enum2$<msvc_pretty_enums::ArbitraryDiscr>]
// cdb-check: [+0x[...]] __0 : 5678 [Type: unsigned int]
//
// cdb-command: dx c_style_u128_a
// cdb-check: c_style_u128_a : A [Type: enum2$<msvc_pretty_enums::CStyleU128>]
//
// cdb-command: dx c_style_u128_b
// cdb-check: c_style_u128_b : B [Type: enum2$<msvc_pretty_enums::CStyleU128>]
//
// cdb-command: dx c_style_u128_c
// cdb-check: c_style_u128_c : C [Type: enum2$<msvc_pretty_enums::CStyleU128>]
//
// cdb-command: dx c_style_u128_d
// cdb-check: c_style_u128_d : D [Type: enum2$<msvc_pretty_enums::CStyleU128>]
//
// cdb-command: dx c_style_i128_a
// cdb-check: c_style_i128_a : A [Type: enum2$<msvc_pretty_enums::CStyleI128>]
//
// cdb-command: dx c_style_i128_b
// cdb-check: c_style_i128_b : B [Type: enum2$<msvc_pretty_enums::CStyleI128>]
//
// cdb-command: dx c_style_i128_c
// cdb-check: c_style_i128_c : C [Type: enum2$<msvc_pretty_enums::CStyleI128>]
//
// cdb-command: dx c_style_i128_d
// cdb-check: c_style_i128_d : D [Type: enum2$<msvc_pretty_enums::CStyleI128>]
#![feature(rustc_attrs)]
#![feature(repr128)]
#![feature(arbitrary_enum_discriminant)]
Expand Down Expand Up @@ -270,6 +294,22 @@ enum ArbitraryDiscr {
Def(u32) = 5000_000,
}

#[repr(u128)]
pub enum CStyleU128 {
A = 0_u128,
B = 1_u128,
C = u64::MAX as u128 + 1,
D = u128::MAX,
}

#[repr(i128)]
pub enum CStyleI128 {
A = 0_i128,
B = -1_i128,
C = i128::MIN,
D = i128::MAX,
}

fn main() {
let a = Some(CStyleEnum::Low);
let b = Option::<CStyleEnum>::None;
Expand Down Expand Up @@ -313,6 +353,16 @@ fn main() {
let arbitrary_discr1 = ArbitraryDiscr::Abc(1234);
let arbitrary_discr2 = ArbitraryDiscr::Def(5678);

let c_style_u128_a = CStyleU128::A;
let c_style_u128_b = CStyleU128::B;
let c_style_u128_c = CStyleU128::C;
let c_style_u128_d = CStyleU128::D;

let c_style_i128_a = CStyleI128::A;
let c_style_i128_b = CStyleI128::B;
let c_style_i128_c = CStyleI128::C;
let c_style_i128_d = CStyleI128::D;

zzz(); // #break
}

Expand Down

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