From 44d185b0d00c8ba228aafa789a39b77d7fd11daf Mon Sep 17 00:00:00 2001 From: Kevin Reid Date: Fri, 22 Mar 2024 16:45:32 -0700 Subject: [PATCH] -Zprint-type-sizes: print the types of awaitees and unnamed coroutine locals. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This should assist comprehending the size of coroutines. In particular, whenever a future is suspended while awaiting another future, the latter is given the special name `__awaitee`, and now the type of the awaited future will be printed, allowing identifying caller/callee — er, I mean, poller/pollee — relationships. It would be possible to include the type name in more cases, but I thought that that might be overly verbose (`print-type-sizes` is already a lot of text) and ordinary named fields or variables are easier for readers to discover the types of. --- compiler/rustc_session/src/code_stats.rs | 18 ++++++++++++++---- compiler/rustc_ty_utils/src/layout.rs | 10 +++++++++- .../future-sizes/async-awaiting-fut.stdout | 14 +++++++------- .../async-await/future-sizes/large-arg.stdout | 6 +++--- tests/ui/print_type_sizes/async.stdout | 2 +- 5 files changed, 34 insertions(+), 16 deletions(-) diff --git a/compiler/rustc_session/src/code_stats.rs b/compiler/rustc_session/src/code_stats.rs index 2553df33cc765..93839fa1186af 100644 --- a/compiler/rustc_session/src/code_stats.rs +++ b/compiler/rustc_session/src/code_stats.rs @@ -44,6 +44,10 @@ pub struct FieldInfo { pub offset: u64, pub size: u64, pub align: u64, + /// Name of the type of this field. + /// Present only if the creator thought that this would be important for identifying the field, + /// typically because the field name is uninformative. + pub type_name: Option, } #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)] @@ -192,7 +196,7 @@ impl CodeStats { fields.sort_by_key(|f| (f.offset, f.size)); for field in fields { - let FieldInfo { kind, ref name, offset, size, align } = field; + let FieldInfo { kind, ref name, offset, size, align, type_name } = field; if offset > min_offset { let pad = offset - min_offset; @@ -201,21 +205,27 @@ impl CodeStats { if offset < min_offset { // If this happens it's probably a union. - println!( + print!( "print-type-size {indent}{kind} `.{name}`: {size} bytes, \ offset: {offset} bytes, \ alignment: {align} bytes" ); } else if info.packed || offset == min_offset { - println!("print-type-size {indent}{kind} `.{name}`: {size} bytes"); + print!("print-type-size {indent}{kind} `.{name}`: {size} bytes"); } else { // Include field alignment in output only if it caused padding injection - println!( + print!( "print-type-size {indent}{kind} `.{name}`: {size} bytes, \ alignment: {align} bytes" ); } + if let Some(type_name) = type_name { + println!(", type: {type_name}"); + } else { + println!(); + } + min_offset = offset + size; } } diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs index 48e76d50be169..9c3d39307b26f 100644 --- a/compiler/rustc_ty_utils/src/layout.rs +++ b/compiler/rustc_ty_utils/src/layout.rs @@ -10,6 +10,7 @@ use rustc_middle::ty::layout::{ use rustc_middle::ty::print::with_no_trimmed_paths; use rustc_middle::ty::{self, AdtDef, EarlyBinder, GenericArgsRef, Ty, TyCtxt, TypeVisitableExt}; use rustc_session::{DataTypeKind, FieldInfo, FieldKind, SizeKind, VariantInfo}; +use rustc_span::sym; use rustc_span::symbol::Symbol; use rustc_target::abi::*; @@ -1007,6 +1008,7 @@ fn variant_info_for_adt<'tcx>( offset: offset.bytes(), size: field_layout.size.bytes(), align: field_layout.align.abi.bytes(), + type_name: None, } }) .collect(); @@ -1090,6 +1092,7 @@ fn variant_info_for_coroutine<'tcx>( offset: offset.bytes(), size: field_layout.size.bytes(), align: field_layout.align.abi.bytes(), + type_name: None, } }) .collect(); @@ -1104,19 +1107,24 @@ fn variant_info_for_coroutine<'tcx>( .iter() .enumerate() .map(|(field_idx, local)| { + let field_name = coroutine.field_names[*local]; let field_layout = variant_layout.field(cx, field_idx); let offset = variant_layout.fields.offset(field_idx); // The struct is as large as the last field's end variant_size = variant_size.max(offset + field_layout.size); FieldInfo { kind: FieldKind::CoroutineLocal, - name: coroutine.field_names[*local].unwrap_or(Symbol::intern(&format!( + name: field_name.unwrap_or(Symbol::intern(&format!( ".coroutine_field{}", local.as_usize() ))), offset: offset.bytes(), size: field_layout.size.bytes(), align: field_layout.align.abi.bytes(), + // Include the type name if there is no field name, or if the name is the + // __awaitee placeholder symbol which means a child future being `.await`ed. + type_name: (field_name.is_none() || field_name == Some(sym::__awaitee)) + .then(|| Symbol::intern(&field_layout.ty.to_string())), } }) .chain(upvar_fields.iter().copied()) diff --git a/tests/ui/async-await/future-sizes/async-awaiting-fut.stdout b/tests/ui/async-await/future-sizes/async-awaiting-fut.stdout index 47b39e5246dde..d6fb643702c56 100644 --- a/tests/ui/async-await/future-sizes/async-awaiting-fut.stdout +++ b/tests/ui/async-await/future-sizes/async-awaiting-fut.stdout @@ -2,7 +2,7 @@ print-type-size type: `{async fn body@$DIR/async-awaiting-fut.rs:21:21: 24:2}`: print-type-size discriminant: 1 bytes print-type-size variant `Unresumed`: 0 bytes print-type-size variant `Suspend0`: 3077 bytes -print-type-size local `.__awaitee`: 3077 bytes +print-type-size local `.__awaitee`: 3077 bytes, type: {async fn body@$DIR/async-awaiting-fut.rs:10:64: 19:2} print-type-size variant `Returned`: 0 bytes print-type-size variant `Panicked`: 0 bytes print-type-size type: `std::mem::ManuallyDrop<{async fn body@$DIR/async-awaiting-fut.rs:10:64: 19:2}>`: 3077 bytes, alignment: 1 bytes @@ -19,19 +19,19 @@ print-type-size variant `Suspend0`: 2052 bytes print-type-size upvar `.fut`: 1025 bytes, offset: 0 bytes, alignment: 1 bytes print-type-size padding: 1 bytes print-type-size local `.fut`: 1025 bytes, alignment: 1 bytes -print-type-size local `..coroutine_field4`: 1 bytes -print-type-size local `.__awaitee`: 1 bytes +print-type-size local `..coroutine_field4`: 1 bytes, type: bool +print-type-size local `.__awaitee`: 1 bytes, type: {async fn body@$DIR/async-awaiting-fut.rs:6:17: 6:19} print-type-size variant `Suspend1`: 3076 bytes print-type-size upvar `.fut`: 1025 bytes, offset: 0 bytes, alignment: 1 bytes print-type-size padding: 1026 bytes -print-type-size local `..coroutine_field4`: 1 bytes, alignment: 1 bytes -print-type-size local `.__awaitee`: 1025 bytes +print-type-size local `..coroutine_field4`: 1 bytes, alignment: 1 bytes, type: bool +print-type-size local `.__awaitee`: 1025 bytes, type: {async fn body@$DIR/async-awaiting-fut.rs:8:35: 8:37} print-type-size variant `Suspend2`: 2052 bytes print-type-size upvar `.fut`: 1025 bytes, offset: 0 bytes, alignment: 1 bytes print-type-size padding: 1 bytes print-type-size local `.fut`: 1025 bytes, alignment: 1 bytes -print-type-size local `..coroutine_field4`: 1 bytes -print-type-size local `.__awaitee`: 1 bytes +print-type-size local `..coroutine_field4`: 1 bytes, type: bool +print-type-size local `.__awaitee`: 1 bytes, type: {async fn body@$DIR/async-awaiting-fut.rs:6:17: 6:19} print-type-size variant `Returned`: 1025 bytes print-type-size upvar `.fut`: 1025 bytes, offset: 0 bytes, alignment: 1 bytes print-type-size variant `Panicked`: 1025 bytes diff --git a/tests/ui/async-await/future-sizes/large-arg.stdout b/tests/ui/async-await/future-sizes/large-arg.stdout index 005460df626fc..589df102af4bd 100644 --- a/tests/ui/async-await/future-sizes/large-arg.stdout +++ b/tests/ui/async-await/future-sizes/large-arg.stdout @@ -2,7 +2,7 @@ print-type-size type: `{async fn body@$DIR/large-arg.rs:6:21: 8:2}`: 3076 bytes, print-type-size discriminant: 1 bytes print-type-size variant `Unresumed`: 0 bytes print-type-size variant `Suspend0`: 3075 bytes -print-type-size local `.__awaitee`: 3075 bytes +print-type-size local `.__awaitee`: 3075 bytes, type: {async fn body@$DIR/large-arg.rs:10:30: 12:2} print-type-size variant `Returned`: 0 bytes print-type-size variant `Panicked`: 0 bytes print-type-size type: `std::mem::ManuallyDrop<{async fn body@$DIR/large-arg.rs:10:30: 12:2}>`: 3075 bytes, alignment: 1 bytes @@ -17,7 +17,7 @@ print-type-size variant `Unresumed`: 1024 bytes print-type-size upvar `.t`: 1024 bytes print-type-size variant `Suspend0`: 3074 bytes print-type-size upvar `.t`: 1024 bytes -print-type-size local `.__awaitee`: 2050 bytes +print-type-size local `.__awaitee`: 2050 bytes, type: {async fn body@$DIR/large-arg.rs:13:26: 15:2} print-type-size variant `Returned`: 1024 bytes print-type-size upvar `.t`: 1024 bytes print-type-size variant `Panicked`: 1024 bytes @@ -34,7 +34,7 @@ print-type-size variant `Unresumed`: 1024 bytes print-type-size upvar `.t`: 1024 bytes print-type-size variant `Suspend0`: 2049 bytes print-type-size upvar `.t`: 1024 bytes -print-type-size local `.__awaitee`: 1025 bytes +print-type-size local `.__awaitee`: 1025 bytes, type: {async fn body@$DIR/large-arg.rs:16:26: 18:2} print-type-size variant `Returned`: 1024 bytes print-type-size upvar `.t`: 1024 bytes print-type-size variant `Panicked`: 1024 bytes diff --git a/tests/ui/print_type_sizes/async.stdout b/tests/ui/print_type_sizes/async.stdout index e1be98f85d847..1df4d85d09e33 100644 --- a/tests/ui/print_type_sizes/async.stdout +++ b/tests/ui/print_type_sizes/async.stdout @@ -5,7 +5,7 @@ print-type-size upvar `.arg`: 8192 bytes print-type-size variant `Suspend0`: 16385 bytes print-type-size upvar `.arg`: 8192 bytes print-type-size local `.arg`: 8192 bytes -print-type-size local `.__awaitee`: 1 bytes +print-type-size local `.__awaitee`: 1 bytes, type: {async fn body@$DIR/async.rs:8:17: 8:19} print-type-size variant `Returned`: 8192 bytes print-type-size upvar `.arg`: 8192 bytes print-type-size variant `Panicked`: 8192 bytes