From 8e54caba04bbb040b2221da2bbaa6d11655f09f5 Mon Sep 17 00:00:00 2001
From: Chris Copeland <chris@chrisnc.net>
Date: Mon, 17 Jul 2023 22:13:15 -0700
Subject: [PATCH] Fix comments about GCC/Clang's enum width for arm-none
 targets.

GCC uses the `-fshort-enums` ABI for arm-none and the `int`-sized enum
ABI for arm-linux.
Clang uses the `int`-sized enum ABI for all arm targets.

Both options are permitted by AAPCS.

Rust is matching GCC's behavior for these targets, as interop with code
code compiled by GCC is desirable in the bare-metal context. See #87917.
---
 compiler/rustc_target/src/spec/armebv7r_none_eabi.rs   | 2 +-
 compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs | 2 +-
 compiler/rustc_target/src/spec/armv4t_none_eabi.rs     | 4 ++--
 compiler/rustc_target/src/spec/armv7a_none_eabihf.rs   | 2 +-
 compiler/rustc_target/src/spec/armv7r_none_eabi.rs     | 2 +-
 compiler/rustc_target/src/spec/armv7r_none_eabihf.rs   | 2 +-
 compiler/rustc_target/src/spec/thumb_base.rs           | 2 +-
 7 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs b/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs
index f9a1fd821a6..446efa90d09 100644
--- a/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs
+++ b/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs
@@ -18,7 +18,7 @@ pub fn target() -> Target {
             panic_strategy: PanicStrategy::Abort,
             max_atomic_width: Some(64),
             emit_debug_gdb_scripts: false,
-            // GCC and Clang default to 8 for arm-none here
+            // GCC defaults to 8 for arm-none here.
             c_enum_min_bits: Some(8),
             ..Default::default()
         },
diff --git a/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs b/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs
index 837a4166121..0c9e99ff84b 100644
--- a/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs
+++ b/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs
@@ -19,7 +19,7 @@ pub fn target() -> Target {
             features: "+vfp3,-d32,-fp16".into(),
             max_atomic_width: Some(64),
             emit_debug_gdb_scripts: false,
-            // GCC and Clang default to 8 for arm-none here
+            // GCC defaults to 8 for arm-none here.
             c_enum_min_bits: Some(8),
             ..Default::default()
         },
diff --git a/compiler/rustc_target/src/spec/armv4t_none_eabi.rs b/compiler/rustc_target/src/spec/armv4t_none_eabi.rs
index d0f988b278f..44fdd3178af 100644
--- a/compiler/rustc_target/src/spec/armv4t_none_eabi.rs
+++ b/compiler/rustc_target/src/spec/armv4t_none_eabi.rs
@@ -39,9 +39,9 @@ pub fn target() -> Target {
             has_thumb_interworking: true,
             relocation_model: RelocModel::Static,
             panic_strategy: PanicStrategy::Abort,
-            // from thumb_base, rust-lang/rust#44993.
+            // From thumb_base, rust-lang/rust#44993.
             emit_debug_gdb_scripts: false,
-            // from thumb_base, apparently gcc/clang give enums a minimum of 8 bits on no-os targets
+            // From thumb_base, GCC gives enums a minimum of 8 bits on no-os targets.
             c_enum_min_bits: Some(8),
             ..Default::default()
         },
diff --git a/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs b/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs
index 8cdf3c36ba2..c134f3e0907 100644
--- a/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs
+++ b/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs
@@ -18,7 +18,7 @@ pub fn target() -> Target {
         max_atomic_width: Some(64),
         panic_strategy: PanicStrategy::Abort,
         emit_debug_gdb_scripts: false,
-        // GCC and Clang default to 8 for arm-none here
+        // GCC defaults to 8 for arm-none here.
         c_enum_min_bits: Some(8),
         ..Default::default()
     };
diff --git a/compiler/rustc_target/src/spec/armv7r_none_eabi.rs b/compiler/rustc_target/src/spec/armv7r_none_eabi.rs
index a2864b385d7..68b2527985a 100644
--- a/compiler/rustc_target/src/spec/armv7r_none_eabi.rs
+++ b/compiler/rustc_target/src/spec/armv7r_none_eabi.rs
@@ -17,7 +17,7 @@ pub fn target() -> Target {
             panic_strategy: PanicStrategy::Abort,
             max_atomic_width: Some(64),
             emit_debug_gdb_scripts: false,
-            // GCC and Clang default to 8 for arm-none here
+            // GCC defaults to 8 for arm-none here.
             c_enum_min_bits: Some(8),
             ..Default::default()
         },
diff --git a/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs b/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs
index 6a51cbd49c5..909765a310f 100644
--- a/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs
+++ b/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs
@@ -18,7 +18,7 @@ pub fn target() -> Target {
             features: "+vfp3,-d32,-fp16".into(),
             max_atomic_width: Some(64),
             emit_debug_gdb_scripts: false,
-            // GCC and Clang default to 8 for arm-none here
+            // GCC defaults to 8 for arm-none here.
             c_enum_min_bits: Some(8),
             ..Default::default()
         },
diff --git a/compiler/rustc_target/src/spec/thumb_base.rs b/compiler/rustc_target/src/spec/thumb_base.rs
index 2220b9326c9..0decfecb4cd 100644
--- a/compiler/rustc_target/src/spec/thumb_base.rs
+++ b/compiler/rustc_target/src/spec/thumb_base.rs
@@ -52,7 +52,7 @@ pub fn opts() -> TargetOptions {
         // breaks debugging. Preserve LR by default to prevent that from happening.
         frame_pointer: FramePointer::Always,
         // ARM supports multiple ABIs for enums, the linux one matches the default of 32 here
-        // but any arm-none or thumb-none target will be defaulted to 8 on GCC and clang
+        // but any arm-none or thumb-none target will be defaulted to 8 on GCC.
         c_enum_min_bits: Some(8),
         ..Default::default()
     }