Rollup merge of #92873 - eholk:async-symbol-names, r=tmandry

Generate more precise generator names

Currently all generators are named with a `generator$N` suffix, regardless of where they come from. This means an `async fn` shows up as a generator in stack traces, which can be surprising to async programmers since they should not need to know that async functions are implementated using generators.

This change generators a different name depending on the generator kind, allowing us to tell whether the generator is the result of an async block, an async closure, an async fn, or a plain generator.

r? `@tmandry`
cc `@michaelwoerister` `@wesleywiser` `@dpaoliello`
This commit is contained in:
Matthias Krüger 2022-01-15 11:28:26 +01:00 committed by GitHub
commit 85c119cd51
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3 changed files with 10 additions and 4 deletions

View file

@ -519,12 +519,18 @@ fn push_unqualified_item_name(
output.push_str(tcx.crate_name(def_id.krate).as_str());
}
DefPathData::ClosureExpr if tcx.generator_kind(def_id).is_some() => {
let key = match tcx.generator_kind(def_id).unwrap() {
hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Block) => "async_block",
hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Closure) => "async_closure",
hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Fn) => "async_fn",
hir::GeneratorKind::Gen => "generator",
};
// Generators look like closures, but we want to treat them differently
// in the debug info.
if cpp_like_debuginfo(tcx) {
write!(output, "generator${}", disambiguated_data.disambiguator).unwrap();
write!(output, "{}${}", key, disambiguated_data.disambiguator).unwrap();
} else {
write!(output, "{{generator#{}}}", disambiguated_data.disambiguator).unwrap();
write!(output, "{{{}#{}}}", key, disambiguated_data.disambiguator).unwrap();
}
}
_ => match disambiguated_data.data.name() {

View file

@ -17,7 +17,7 @@ async fn async_fn_test() {
// FIXME: No way to reliably check the filename.
// CHECK-DAG: [[ASYNC_FN:!.*]] = !DINamespace(name: "async_fn_test"
// CHECK-DAG: [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_union_type, name: "generator$0"
// CHECK-DAG: [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_union_type, name: "async_fn$0"
// CHECK: {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "variant0", scope: [[GEN]],
// For brevity, we only check the struct name and members of the last variant.
// CHECK-SAME: file: [[FILE:![0-9]*]], line: 11,

View file

@ -17,7 +17,7 @@ async fn async_fn_test() {
// FIXME: No way to reliably check the filename.
// CHECK-DAG: [[ASYNC_FN:!.*]] = !DINamespace(name: "async_fn_test"
// CHECK-DAG: [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "{generator#0}", scope: [[ASYNC_FN]]
// CHECK-DAG: [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn#0}", scope: [[ASYNC_FN]]
// CHECK: [[VARIANT:!.*]] = !DICompositeType(tag: DW_TAG_variant_part, scope: [[ASYNC_FN]],
// CHECK-NOT: flags: DIFlagArtificial
// CHECK-SAME: discriminator: [[DISC:![0-9]*]]