rustc_codegen_ssa/debuginfo/type_names.rs
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//! Type Names for Debug Info.
// Notes on targeting MSVC:
// In general, MSVC's debugger attempts to parse all arguments as C++ expressions,
// even if the argument is explicitly a symbol name.
// As such, there are many things that cause parsing issues:
// * `#` is treated as a special character for macros.
// * `{` or `<` at the beginning of a name is treated as an operator.
// * `>>` is always treated as a right-shift.
// * `[` in a name is treated like a regex bracket expression (match any char
// within the brackets).
// * `"` is treated as the start of a string.
use std::fmt::Write;
use rustc_data_structures::fx::FxHashSet;
use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher};
use rustc_hir::def_id::DefId;
use rustc_hir::definitions::{DefPathData, DefPathDataName, DisambiguatedDefPathData};
use rustc_hir::{CoroutineDesugaring, CoroutineKind, CoroutineSource, Mutability};
use rustc_middle::bug;
use rustc_middle::ty::layout::{IntegerExt, TyAndLayout};
use rustc_middle::ty::{
self, ExistentialProjection, GenericArgKind, GenericArgsRef, ParamEnv, Ty, TyCtxt,
};
use rustc_span::DUMMY_SP;
use rustc_target::abi::Integer;
use smallvec::SmallVec;
use crate::debuginfo::wants_c_like_enum_debuginfo;
/// Compute the name of the type as it should be stored in debuginfo. Does not do
/// any caching, i.e., calling the function twice with the same type will also do
/// the work twice. The `qualified` parameter only affects the first level of the
/// type name, further levels (i.e., type parameters) are always fully qualified.
pub fn compute_debuginfo_type_name<'tcx>(
tcx: TyCtxt<'tcx>,
t: Ty<'tcx>,
qualified: bool,
) -> String {
let _prof = tcx.prof.generic_activity("compute_debuginfo_type_name");
let mut result = String::with_capacity(64);
let mut visited = FxHashSet::default();
push_debuginfo_type_name(tcx, t, qualified, &mut result, &mut visited);
result
}
// Pushes the name of the type as it should be stored in debuginfo on the
// `output` String. See also compute_debuginfo_type_name().
fn push_debuginfo_type_name<'tcx>(
tcx: TyCtxt<'tcx>,
t: Ty<'tcx>,
qualified: bool,
output: &mut String,
visited: &mut FxHashSet<Ty<'tcx>>,
) {
// When targeting MSVC, emit C++ style type names for compatibility with
// .natvis visualizers (and perhaps other existing native debuggers?)
let cpp_like_debuginfo = cpp_like_debuginfo(tcx);
match *t.kind() {
ty::Bool => output.push_str("bool"),
ty::Char => output.push_str("char"),
ty::Str => {
if cpp_like_debuginfo {
output.push_str("str$")
} else {
output.push_str("str")
}
}
ty::Never => {
if cpp_like_debuginfo {
output.push_str("never$");
} else {
output.push('!');
}
}
ty::Int(int_ty) => output.push_str(int_ty.name_str()),
ty::Uint(uint_ty) => output.push_str(uint_ty.name_str()),
ty::Float(float_ty) => output.push_str(float_ty.name_str()),
ty::Foreign(def_id) => push_item_name(tcx, def_id, qualified, output),
ty::Adt(def, args) => {
// `layout_for_cpp_like_fallback` will be `Some` if we want to use the fallback encoding.
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(tcx, layout) {
Some(layout)
} else {
// This is a C-like enum so we don't want to use the fallback encoding
// for the name.
None
}
}
Err(e) => {
// Computing the layout can still fail here, e.g. if the target architecture
// cannot represent the type. See
// https://github.com/rust-lang/rust/issues/94961.
tcx.dcx().emit_fatal(e.into_diagnostic());
}
}
} else {
// We are not emitting cpp-like debuginfo or this isn't even an enum.
None
};
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);
push_generic_params_internal(tcx, args, def.did(), output, visited);
},
output,
visited,
);
} else {
push_item_name(tcx, def.did(), qualified, output);
push_generic_params_internal(tcx, args, def.did(), output, visited);
}
}
ty::Tuple(component_types) => {
if cpp_like_debuginfo {
output.push_str("tuple$<");
} else {
output.push('(');
}
for component_type in component_types {
push_debuginfo_type_name(tcx, component_type, true, output, visited);
push_arg_separator(cpp_like_debuginfo, output);
}
if !component_types.is_empty() {
pop_arg_separator(output);
}
if cpp_like_debuginfo {
push_close_angle_bracket(cpp_like_debuginfo, output);
} else {
output.push(')');
}
}
ty::RawPtr(inner_type, mutbl) => {
if cpp_like_debuginfo {
match mutbl {
Mutability::Not => output.push_str("ptr_const$<"),
Mutability::Mut => output.push_str("ptr_mut$<"),
}
} else {
output.push('*');
match mutbl {
Mutability::Not => output.push_str("const "),
Mutability::Mut => output.push_str("mut "),
}
}
push_debuginfo_type_name(tcx, inner_type, qualified, output, visited);
if cpp_like_debuginfo {
push_close_angle_bracket(cpp_like_debuginfo, output);
}
}
ty::Ref(_, inner_type, mutbl) => {
if cpp_like_debuginfo {
match mutbl {
Mutability::Not => output.push_str("ref$<"),
Mutability::Mut => output.push_str("ref_mut$<"),
}
} else {
output.push('&');
output.push_str(mutbl.prefix_str());
}
push_debuginfo_type_name(tcx, inner_type, qualified, output, visited);
if cpp_like_debuginfo {
push_close_angle_bracket(cpp_like_debuginfo, output);
}
}
ty::Array(inner_type, len) => {
if cpp_like_debuginfo {
output.push_str("array$<");
push_debuginfo_type_name(tcx, inner_type, true, output, visited);
match len.kind() {
ty::ConstKind::Param(param) => write!(output, ",{}>", param.name).unwrap(),
_ => write!(
output,
",{}>",
len.try_to_target_usize(tcx)
.expect("expected monomorphic const in codegen")
)
.unwrap(),
}
} else {
output.push('[');
push_debuginfo_type_name(tcx, inner_type, true, output, visited);
match len.kind() {
ty::ConstKind::Param(param) => write!(output, "; {}]", param.name).unwrap(),
_ => write!(
output,
"; {}]",
len.try_to_target_usize(tcx)
.expect("expected monomorphic const in codegen")
)
.unwrap(),
}
}
}
ty::Pat(inner_type, pat) => {
if cpp_like_debuginfo {
output.push_str("pat$<");
push_debuginfo_type_name(tcx, inner_type, true, output, visited);
// FIXME(wg-debugging): implement CPP like printing for patterns.
write!(output, ",{:?}>", pat).unwrap();
} else {
write!(output, "{:?}", t).unwrap();
}
}
ty::Slice(inner_type) => {
if cpp_like_debuginfo {
output.push_str("slice2$<");
} else {
output.push('[');
}
push_debuginfo_type_name(tcx, inner_type, true, output, visited);
if cpp_like_debuginfo {
push_close_angle_bracket(cpp_like_debuginfo, output);
} else {
output.push(']');
}
}
ty::Dynamic(trait_data, ..) => {
let auto_traits: SmallVec<[DefId; 4]> = trait_data.auto_traits().collect();
let has_enclosing_parens = if cpp_like_debuginfo {
output.push_str("dyn$<");
false
} else if trait_data.len() > 1 && auto_traits.len() != 0 {
// We need enclosing parens because there is more than one trait
output.push_str("(dyn ");
true
} else {
output.push_str("dyn ");
false
};
if let Some(principal) = trait_data.principal() {
let principal =
tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), principal);
push_item_name(tcx, principal.def_id, qualified, output);
let principal_has_generic_params = push_generic_params_internal(
tcx,
principal.args,
principal.def_id,
output,
visited,
);
let projection_bounds: SmallVec<[_; 4]> = trait_data
.projection_bounds()
.map(|bound| {
let ExistentialProjection { def_id: item_def_id, term, .. } =
tcx.instantiate_bound_regions_with_erased(bound);
// FIXME(associated_const_equality): allow for consts here
(item_def_id, term.expect_type())
})
.collect();
if projection_bounds.len() != 0 {
if principal_has_generic_params {
// push_generic_params_internal() above added a `>` but we actually
// want to add more items to that list, so remove that again...
pop_close_angle_bracket(output);
// .. and add a comma to separate the regular generic args from the
// associated types.
push_arg_separator(cpp_like_debuginfo, output);
} else {
// push_generic_params_internal() did not add `<...>`, so we open
// angle brackets here.
output.push('<');
}
for (item_def_id, ty) in projection_bounds {
if cpp_like_debuginfo {
output.push_str("assoc$<");
push_item_name(tcx, item_def_id, false, output);
push_arg_separator(cpp_like_debuginfo, output);
push_debuginfo_type_name(tcx, ty, true, output, visited);
push_close_angle_bracket(cpp_like_debuginfo, output);
} else {
push_item_name(tcx, item_def_id, false, output);
output.push('=');
push_debuginfo_type_name(tcx, ty, true, output, visited);
}
push_arg_separator(cpp_like_debuginfo, output);
}
pop_arg_separator(output);
push_close_angle_bracket(cpp_like_debuginfo, output);
}
if auto_traits.len() != 0 {
push_auto_trait_separator(cpp_like_debuginfo, output);
}
}
if auto_traits.len() != 0 {
let mut auto_traits: SmallVec<[String; 4]> = auto_traits
.into_iter()
.map(|def_id| {
let mut name = String::with_capacity(20);
push_item_name(tcx, def_id, true, &mut name);
name
})
.collect();
auto_traits.sort_unstable();
for auto_trait in auto_traits {
output.push_str(&auto_trait);
push_auto_trait_separator(cpp_like_debuginfo, output);
}
pop_auto_trait_separator(output);
}
if cpp_like_debuginfo {
push_close_angle_bracket(cpp_like_debuginfo, output);
} else if has_enclosing_parens {
output.push(')');
}
}
ty::FnDef(..) | ty::FnPtr(..) => {
// We've encountered a weird 'recursive type'
// Currently, the only way to generate such a type
// is by using 'impl trait':
//
// fn foo() -> impl Copy { foo }
//
// There's not really a sensible name we can generate,
// since we don't include 'impl trait' types (e.g. ty::Opaque)
// in the output
//
// Since we need to generate *something*, we just
// use a dummy string that should make it clear
// that something unusual is going on
if !visited.insert(t) {
output.push_str(if cpp_like_debuginfo {
"recursive_type$"
} else {
"<recursive_type>"
});
return;
}
let sig =
tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), t.fn_sig(tcx));
if cpp_like_debuginfo {
// Format as a C++ function pointer: return_type (*)(params...)
if sig.output().is_unit() {
output.push_str("void");
} else {
push_debuginfo_type_name(tcx, sig.output(), true, output, visited);
}
output.push_str(" (*)(");
} else {
output.push_str(sig.safety.prefix_str());
if sig.abi != rustc_target::spec::abi::Abi::Rust {
output.push_str("extern \"");
output.push_str(sig.abi.name());
output.push_str("\" ");
}
output.push_str("fn(");
}
if !sig.inputs().is_empty() {
for ¶meter_type in sig.inputs() {
push_debuginfo_type_name(tcx, parameter_type, true, output, visited);
push_arg_separator(cpp_like_debuginfo, output);
}
pop_arg_separator(output);
}
if sig.c_variadic {
if !sig.inputs().is_empty() {
output.push_str(", ...");
} else {
output.push_str("...");
}
}
output.push(')');
if !cpp_like_debuginfo && !sig.output().is_unit() {
output.push_str(" -> ");
push_debuginfo_type_name(tcx, sig.output(), true, output, visited);
}
// We only keep the type in 'visited'
// for the duration of the body of this method.
// It's fine for a particular function type
// to show up multiple times in one overall type
// (e.g. MyType<fn() -> u8, fn() -> u8>
//
// We only care about avoiding recursing
// directly back to the type we're currently
// processing
visited.remove(&t);
}
ty::Closure(def_id, args)
| ty::CoroutineClosure(def_id, args)
| ty::Coroutine(def_id, args, ..) => {
// Name will be "{closure_env#0}<T1, T2, ...>", "{coroutine_env#0}<T1, T2, ...>", or
// "{async_fn_env#0}<T1, T2, ...>", etc.
// In the case of cpp-like debuginfo, the name additionally gets wrapped inside of
// an artificial `enum2$<>` type, as defined in msvc_enum_fallback().
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);
},
output,
visited,
);
} else {
push_closure_or_coroutine_name(tcx, def_id, args, qualified, output, visited);
}
}
// Type parameters from polymorphized functions.
ty::Param(_) => {
write!(output, "{t:?}").unwrap();
}
ty::Error(_)
| ty::Infer(_)
| ty::Placeholder(..)
| ty::Alias(..)
| ty::Bound(..)
| ty::CoroutineWitness(..) => {
bug!(
"debuginfo: Trying to create type name for \
unexpected type: {:?}",
t
);
}
}
/// 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
// 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(tcx, ty_and_layout));
output.push_str("enum2$<");
push_inner(output, visited);
push_close_angle_bracket(true, output);
}
const NON_CPP_AUTO_TRAIT_SEPARATOR: &str = " + ";
fn push_auto_trait_separator(cpp_like_debuginfo: bool, output: &mut String) {
if cpp_like_debuginfo {
push_arg_separator(cpp_like_debuginfo, output);
} else {
output.push_str(NON_CPP_AUTO_TRAIT_SEPARATOR);
}
}
fn pop_auto_trait_separator(output: &mut String) {
if output.ends_with(NON_CPP_AUTO_TRAIT_SEPARATOR) {
output.truncate(output.len() - NON_CPP_AUTO_TRAIT_SEPARATOR.len());
} else {
pop_arg_separator(output);
}
}
}
pub enum VTableNameKind {
// Is the name for the const/static holding the vtable?
GlobalVariable,
// Is the name for the type of the vtable?
Type,
}
/// Computes a name for the global variable storing a vtable (or the type of that global variable).
///
/// The name is of the form:
///
/// `<path::to::SomeType as path::to::SomeTrait>::{vtable}`
///
/// or, when generating C++-like names:
///
/// `impl$<path::to::SomeType, path::to::SomeTrait>::vtable$`
///
/// If `kind` is `VTableNameKind::Type` then the last component is `{vtable_ty}` instead of just
/// `{vtable}`, so that the type and the corresponding global variable get assigned different
/// names.
pub fn compute_debuginfo_vtable_name<'tcx>(
tcx: TyCtxt<'tcx>,
t: Ty<'tcx>,
trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
kind: VTableNameKind,
) -> String {
let cpp_like_debuginfo = cpp_like_debuginfo(tcx);
let mut vtable_name = String::with_capacity(64);
if cpp_like_debuginfo {
vtable_name.push_str("impl$<");
} else {
vtable_name.push('<');
}
let mut visited = FxHashSet::default();
push_debuginfo_type_name(tcx, t, true, &mut vtable_name, &mut visited);
if cpp_like_debuginfo {
vtable_name.push_str(", ");
} else {
vtable_name.push_str(" as ");
}
if let Some(trait_ref) = trait_ref {
let trait_ref =
tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), trait_ref);
push_item_name(tcx, trait_ref.def_id, true, &mut vtable_name);
visited.clear();
push_generic_params_internal(
tcx,
trait_ref.args,
trait_ref.def_id,
&mut vtable_name,
&mut visited,
);
} else {
vtable_name.push('_');
}
push_close_angle_bracket(cpp_like_debuginfo, &mut vtable_name);
let suffix = match (cpp_like_debuginfo, kind) {
(true, VTableNameKind::GlobalVariable) => "::vtable$",
(false, VTableNameKind::GlobalVariable) => "::{vtable}",
(true, VTableNameKind::Type) => "::vtable_type$",
(false, VTableNameKind::Type) => "::{vtable_type}",
};
vtable_name.reserve_exact(suffix.len());
vtable_name.push_str(suffix);
vtable_name
}
pub fn push_item_name(tcx: TyCtxt<'_>, def_id: DefId, qualified: bool, output: &mut String) {
let def_key = tcx.def_key(def_id);
if qualified {
if let Some(parent) = def_key.parent {
push_item_name(tcx, DefId { krate: def_id.krate, index: parent }, true, output);
output.push_str("::");
}
}
push_unqualified_item_name(tcx, def_id, def_key.disambiguated_data, output);
}
fn coroutine_kind_label(coroutine_kind: Option<CoroutineKind>) -> &'static str {
use CoroutineDesugaring::*;
use CoroutineKind::*;
use CoroutineSource::*;
match coroutine_kind {
Some(Desugared(Gen, Block)) => "gen_block",
Some(Desugared(Gen, Closure)) => "gen_closure",
Some(Desugared(Gen, Fn)) => "gen_fn",
Some(Desugared(Async, Block)) => "async_block",
Some(Desugared(Async, Closure)) => "async_closure",
Some(Desugared(Async, Fn)) => "async_fn",
Some(Desugared(AsyncGen, Block)) => "async_gen_block",
Some(Desugared(AsyncGen, Closure)) => "async_gen_closure",
Some(Desugared(AsyncGen, Fn)) => "async_gen_fn",
Some(Coroutine(_)) => "coroutine",
None => "closure",
}
}
fn push_disambiguated_special_name(
label: &str,
disambiguator: u32,
cpp_like_debuginfo: bool,
output: &mut String,
) {
if cpp_like_debuginfo {
write!(output, "{label}${disambiguator}").unwrap();
} else {
write!(output, "{{{label}#{disambiguator}}}").unwrap();
}
}
fn push_unqualified_item_name(
tcx: TyCtxt<'_>,
def_id: DefId,
disambiguated_data: DisambiguatedDefPathData,
output: &mut String,
) {
match disambiguated_data.data {
DefPathData::CrateRoot => {
output.push_str(tcx.crate_name(def_id.krate).as_str());
}
DefPathData::Closure => {
let label = coroutine_kind_label(tcx.coroutine_kind(def_id));
push_disambiguated_special_name(
label,
disambiguated_data.disambiguator,
cpp_like_debuginfo(tcx),
output,
);
}
_ => match disambiguated_data.data.name() {
DefPathDataName::Named(name) => {
output.push_str(name.as_str());
}
DefPathDataName::Anon { namespace } => {
push_disambiguated_special_name(
namespace.as_str(),
disambiguated_data.disambiguator,
cpp_like_debuginfo(tcx),
output,
);
}
},
};
}
fn push_generic_params_internal<'tcx>(
tcx: TyCtxt<'tcx>,
args: GenericArgsRef<'tcx>,
def_id: DefId,
output: &mut String,
visited: &mut FxHashSet<Ty<'tcx>>,
) -> bool {
assert_eq!(args, tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), args));
let mut args = args.non_erasable_generics(tcx, def_id).peekable();
if args.peek().is_none() {
return false;
}
let cpp_like_debuginfo = cpp_like_debuginfo(tcx);
output.push('<');
for type_parameter in args {
match type_parameter {
GenericArgKind::Type(type_parameter) => {
push_debuginfo_type_name(tcx, type_parameter, true, output, visited);
}
GenericArgKind::Const(ct) => {
push_const_param(tcx, ct, output);
}
other => bug!("Unexpected non-erasable generic: {:?}", other),
}
push_arg_separator(cpp_like_debuginfo, output);
}
pop_arg_separator(output);
push_close_angle_bracket(cpp_like_debuginfo, output);
true
}
fn push_const_param<'tcx>(tcx: TyCtxt<'tcx>, ct: ty::Const<'tcx>, output: &mut String) {
match ct.kind() {
ty::ConstKind::Param(param) => {
write!(output, "{}", param.name)
}
ty::ConstKind::Value(ty, _) => {
match ty.kind() {
ty::Int(ity) => {
// FIXME: directly extract the bits from a valtree instead of evaluating an
// already evaluated `Const` in order to get the bits.
let bits = ct.eval_bits(tcx, ty::ParamEnv::reveal_all());
let val = Integer::from_int_ty(&tcx, *ity).size().sign_extend(bits) as i128;
write!(output, "{val}")
}
ty::Uint(_) => {
let val = ct.eval_bits(tcx, ty::ParamEnv::reveal_all());
write!(output, "{val}")
}
ty::Bool => {
let val = ct.try_eval_bool(tcx, ty::ParamEnv::reveal_all()).unwrap();
write!(output, "{val}")
}
_ => {
// If we cannot evaluate the constant to a known type, we fall back
// to emitting a stable hash value of the constant. This isn't very pretty
// but we get a deterministic, virtually unique value for the constant.
//
// Let's only emit 64 bits of the hash value. That should be plenty for
// avoiding collisions and will make the emitted type names shorter.
let hash_short = tcx.with_stable_hashing_context(|mut hcx| {
let mut hasher = StableHasher::new();
let ct = ct.eval(tcx, ty::ParamEnv::reveal_all(), DUMMY_SP).unwrap();
hcx.while_hashing_spans(false, |hcx| ct.hash_stable(hcx, &mut hasher));
hasher.finish::<Hash64>()
});
if cpp_like_debuginfo(tcx) {
write!(output, "CONST${hash_short:x}")
} else {
write!(output, "{{CONST#{hash_short:x}}}")
}
}
}
}
_ => bug!("Invalid `Const` during codegen: {:?}", ct),
}
.unwrap();
}
pub fn push_generic_params<'tcx>(
tcx: TyCtxt<'tcx>,
args: GenericArgsRef<'tcx>,
def_id: DefId,
output: &mut String,
) {
let _prof = tcx.prof.generic_activity("compute_debuginfo_type_name");
let mut visited = FxHashSet::default();
push_generic_params_internal(tcx, args, def_id, output, &mut visited);
}
fn push_closure_or_coroutine_name<'tcx>(
tcx: TyCtxt<'tcx>,
def_id: DefId,
args: GenericArgsRef<'tcx>,
qualified: bool,
output: &mut String,
visited: &mut FxHashSet<Ty<'tcx>>,
) {
// Name will be "{closure_env#0}<T1, T2, ...>", "{coroutine_env#0}<T1, T2, ...>", or
// "{async_fn_env#0}<T1, T2, ...>", etc.
let def_key = tcx.def_key(def_id);
let coroutine_kind = tcx.coroutine_kind(def_id);
if qualified {
let parent_def_id = DefId { index: def_key.parent.unwrap(), ..def_id };
push_item_name(tcx, parent_def_id, true, output);
output.push_str("::");
}
let mut label = String::with_capacity(20);
write!(&mut label, "{}_env", coroutine_kind_label(coroutine_kind)).unwrap();
push_disambiguated_special_name(
&label,
def_key.disambiguated_data.disambiguator,
cpp_like_debuginfo(tcx),
output,
);
// We also need to add the generic arguments of the async fn/coroutine or
// the enclosing function (for closures or async blocks), so that we end
// up with a unique name for every instantiation.
// Find the generics of the enclosing function, as defined in the source code.
let enclosing_fn_def_id = tcx.typeck_root_def_id(def_id);
let generics = tcx.generics_of(enclosing_fn_def_id);
// Truncate the args to the length of the above generics. This will cut off
// anything closure- or coroutine-specific.
// FIXME(async_closures): This is probably not going to be correct w.r.t.
// multiple coroutine flavors. Maybe truncate to (parent + 1)?
let args = args.truncate_to(tcx, generics);
push_generic_params_internal(tcx, args, enclosing_fn_def_id, output, visited);
}
fn push_close_angle_bracket(cpp_like_debuginfo: bool, output: &mut String) {
// MSVC debugger always treats `>>` as a shift, even when parsing templates,
// so add a space to avoid confusion.
if cpp_like_debuginfo && output.ends_with('>') {
output.push(' ')
};
output.push('>');
}
fn pop_close_angle_bracket(output: &mut String) {
assert!(output.ends_with('>'), "'output' does not end with '>': {output}");
output.pop();
if output.ends_with(' ') {
output.pop();
}
}
fn push_arg_separator(cpp_like_debuginfo: bool, output: &mut String) {
// Natvis does not always like having spaces between parts of the type name
// and this causes issues when we need to write a typename in natvis, for example
// as part of a cast like the `HashMap` visualizer does.
if cpp_like_debuginfo {
output.push(',');
} else {
output.push_str(", ");
};
}
fn pop_arg_separator(output: &mut String) {
if output.ends_with(' ') {
output.pop();
}
assert!(output.ends_with(','));
output.pop();
}
/// Check if we should generate C++ like names and debug information.
pub fn cpp_like_debuginfo(tcx: TyCtxt<'_>) -> bool {
tcx.sess.target.is_like_msvc
}