From a37b3061fce5a56d0ed11c79e2c887ab8aa56827 Mon Sep 17 00:00:00 2001
From: "Felix S. Klock II" <pnkfelix@pnkfx.org>
Date: Tue, 31 Jan 2023 15:59:29 -0500
Subject: [PATCH] Extend `-Z print-type-sizes` to distinguish generator upvars
 and locals from "normal" ADT fields.

---
 compiler/rustc_session/src/code_stats.rs | 26 ++++++++++++++++++++----
 compiler/rustc_session/src/session.rs    |  2 +-
 compiler/rustc_ty_utils/src/layout.rs    |  5 ++++-
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/compiler/rustc_session/src/code_stats.rs b/compiler/rustc_session/src/code_stats.rs
index 1085bce4475..f0cd7d9322b 100644
--- a/compiler/rustc_session/src/code_stats.rs
+++ b/compiler/rustc_session/src/code_stats.rs
@@ -19,8 +19,26 @@ pub enum SizeKind {
     Min,
 }
 
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+pub enum FieldKind {
+    AdtField,
+    Upvar,
+    GeneratorLocal,
+}
+
+impl std::fmt::Display for FieldKind {
+    fn fmt(&self, w: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            FieldKind::AdtField => { write!(w, "field") }
+            FieldKind::Upvar => { write!(w, "upvar") }
+            FieldKind::GeneratorLocal => { write!(w, "local") }
+        }
+    }
+}
+
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub struct FieldInfo {
+    pub kind: FieldKind,
     pub name: Symbol,
     pub offset: u64,
     pub size: u64,
@@ -145,7 +163,7 @@ impl CodeStats {
                 fields.sort_by_key(|f| (f.offset, f.size));
 
                 for field in fields {
-                    let FieldInfo { ref name, offset, size, align } = field;
+                    let FieldInfo { kind, ref name, offset, size, align } = field;
 
                     if offset > min_offset {
                         let pad = offset - min_offset;
@@ -155,16 +173,16 @@ impl CodeStats {
                     if offset < min_offset {
                         // If this happens it's probably a union.
                         println!(
-                            "print-type-size {indent}field `.{name}`: {size} bytes, \
+                            "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}field `.{name}`: {size} bytes");
+                        println!("print-type-size {indent}{kind} `.{name}`: {size} bytes");
                     } else {
                         // Include field alignment in output only if it caused padding injection
                         println!(
-                            "print-type-size {indent}field `.{name}`: {size} bytes, \
+                            "print-type-size {indent}{kind} `.{name}`: {size} bytes, \
                                   alignment: {align} bytes"
                         );
                     }
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 91d23f1041f..7cf9b0fd1fa 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -1,6 +1,6 @@
 use crate::cgu_reuse_tracker::CguReuseTracker;
 use crate::code_stats::CodeStats;
-pub use crate::code_stats::{DataTypeKind, FieldInfo, SizeKind, VariantInfo};
+pub use crate::code_stats::{DataTypeKind, FieldInfo, FieldKind, SizeKind, VariantInfo};
 use crate::config::Input;
 use crate::config::{self, CrateType, InstrumentCoverage, OptLevel, OutputType, SwitchWithOptPath};
 use crate::errors::{
diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs
index 378cd5a99ed..93c9c675c9a 100644
--- a/compiler/rustc_ty_utils/src/layout.rs
+++ b/compiler/rustc_ty_utils/src/layout.rs
@@ -9,7 +9,7 @@ use rustc_middle::ty::layout::{
 use rustc_middle::ty::{
     self, subst::SubstsRef, AdtDef, EarlyBinder, ReprOptions, Ty, TyCtxt, TypeVisitable,
 };
-use rustc_session::{DataTypeKind, FieldInfo, SizeKind, VariantInfo};
+use rustc_session::{DataTypeKind, FieldInfo, FieldKind, SizeKind, VariantInfo};
 use rustc_span::symbol::Symbol;
 use rustc_span::DUMMY_SP;
 use rustc_target::abi::*;
@@ -881,6 +881,7 @@ fn variant_info_for_adt<'tcx>(
                 let offset = layout.fields.offset(i);
                 min_size = min_size.max(offset + field_layout.size);
                 FieldInfo {
+                    kind: FieldKind::AdtField,
                     name,
                     offset: offset.bytes(),
                     size: field_layout.size.bytes(),
@@ -960,6 +961,7 @@ fn variant_info_for_generator<'tcx>(
             let offset = layout.fields.offset(field_idx);
             upvars_size = upvars_size.max(offset + field_layout.size);
             FieldInfo {
+                kind: FieldKind::Upvar,
                 name: Symbol::intern(&name),
                 offset: offset.bytes(),
                 size: field_layout.size.bytes(),
@@ -983,6 +985,7 @@ fn variant_info_for_generator<'tcx>(
                     // The struct is as large as the last field's end
                     variant_size = variant_size.max(offset + field_layout.size);
                     FieldInfo {
+                        kind: FieldKind::GeneratorLocal,
                         name: state_specific_names.get(*local).copied().flatten().unwrap_or(
                             Symbol::intern(&format!(".generator_field{}", local.as_usize())),
                         ),