Update to bitflags 2 in the compiler

This involves lots of breaking changes. There are two big changes that
force changes. The first is that the bitflag types now don't
automatically implement normal derive traits, so we need to derive them
manually.

Additionally, bitflags now have a hidden inner type by default, which
breaks our custom derives. The bitflags docs recommend using the impl
form in these cases, which I did.

Author: Noratrieb

compiler/rustc_abi/Cargo.toml

@@ -5,7 +5,7 @@ edition = "2021"
 
 [dependencies]
 # tidy-alphabetical-start
-bitflags = "1.2.1"
+bitflags = "2.4.1"
 rand = { version = "0.8.4", default-features = false, optional = true }
 rand_xoshiro = { version = "0.6.0", optional = true }
 rustc_data_structures = { path = "../rustc_data_structures", optional = true  }

compiler/rustc_abi/src/lib.rs

@@ -29,10 +29,12 @@ pub use layout::LayoutCalculator;
 /// instead of implementing everything in `rustc_middle`.
 pub trait HashStableContext {}
 
+#[derive(Clone, Copy, PartialEq, Eq, Default)]
+#[cfg_attr(feature = "nightly", derive(Encodable, Decodable, HashStable_Generic))]
+pub struct ReprFlags(u8);
+
 bitflags! {
-    #[derive(Default)]
-    #[cfg_attr(feature = "nightly", derive(Encodable, Decodable, HashStable_Generic))]
-    pub struct ReprFlags: u8 {
+    impl ReprFlags: u8 {
         const IS_C               = 1 << 0;
         const IS_SIMD            = 1 << 1;
         const IS_TRANSPARENT     = 1 << 2;
@@ -42,11 +44,12 @@ bitflags! {
         // the seed stored in `ReprOptions.layout_seed`
         const RANDOMIZE_LAYOUT   = 1 << 4;
         // Any of these flags being set prevent field reordering optimisation.
-        const IS_UNOPTIMISABLE   = ReprFlags::IS_C.bits
-                                 | ReprFlags::IS_SIMD.bits
-                                 | ReprFlags::IS_LINEAR.bits;
+        const IS_UNOPTIMISABLE   = ReprFlags::IS_C.bits()
+                                 | ReprFlags::IS_SIMD.bits()
+                                 | ReprFlags::IS_LINEAR.bits();
     }
 }
+rustc_data_structures::external_bitflags_debug! { ReprFlags }
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 #[cfg_attr(feature = "nightly", derive(Encodable, Decodable, HashStable_Generic))]

compiler/rustc_ast/Cargo.toml

@@ -5,7 +5,7 @@ edition = "2021"
 
 [dependencies]
 # tidy-alphabetical-start
-bitflags = "1.2.1"
+bitflags = "2.4.1"
 memchr = "2.5.0"
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_index = { path = "../rustc_index" }

compiler/rustc_ast/src/ast.rs

@@ -2171,9 +2171,10 @@ pub enum InlineAsmRegOrRegClass {
     RegClass(Symbol),
 }
 
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
+pub struct InlineAsmOptions(u16);
 bitflags::bitflags! {
-    #[derive(Encodable, Decodable, HashStable_Generic)]
-    pub struct InlineAsmOptions: u16 {
+    impl InlineAsmOptions: u16 {
         const PURE            = 1 << 0;
         const NOMEM           = 1 << 1;
         const READONLY        = 1 << 2;
@@ -2186,6 +2187,12 @@ bitflags::bitflags! {
     }
 }
 
+impl std::fmt::Debug for InlineAsmOptions {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        bitflags::parser::to_writer(self, f)
+    }
+}
+
 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
 pub enum InlineAsmTemplatePiece {
     String(String),

compiler/rustc_codegen_llvm/Cargo.toml

@@ -8,7 +8,7 @@ test = false
 
 [dependencies]
 # tidy-alphabetical-start
-bitflags = "1.0"
+bitflags = "2.4.1"
 itertools = "0.11"
 libc = "0.2"
 measureme = "10.0.0"

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -722,7 +722,7 @@ pub mod debuginfo {
     // These values **must** match with LLVMRustDIFlags!!
     bitflags! {
         #[repr(transparent)]
-        #[derive(Default)]
+        #[derive(Clone, Copy, Default)]
         pub struct DIFlags: u32 {
             const FlagZero                = 0;
             const FlagPrivate             = 1;
@@ -751,7 +751,7 @@ pub mod debuginfo {
     // These values **must** match with LLVMRustDISPFlags!!
     bitflags! {
         #[repr(transparent)]
-        #[derive(Default)]
+        #[derive(Clone, Copy, Default)]
         pub struct DISPFlags: u32 {
             const SPFlagZero              = 0;
             const SPFlagVirtual           = 1;

compiler/rustc_codegen_ssa/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 [dependencies]
 # tidy-alphabetical-start
 ar_archive_writer = "0.1.5"
-bitflags = "1.2.1"
+bitflags = "2.4.1"
 cc = "1.0.69"
 itertools = "0.11"
 jobserver = "0.1.27"

compiler/rustc_codegen_ssa/src/lib.rs

@@ -110,6 +110,7 @@ pub enum ModuleKind {
 }
 
 bitflags::bitflags! {
+    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
     pub struct MemFlags: u8 {
         const VOLATILE = 1 << 0;
         const NONTEMPORAL = 1 << 1;

compiler/rustc_data_structures/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 [dependencies]
 # tidy-alphabetical-start
 arrayvec = { version = "0.7", default-features = false }
-bitflags = "1.2.1"
+bitflags = "2.4.1"
 elsa = "=1.7.1"
 ena = "0.14.2"
 indexmap = { version = "2.0.0" }

compiler/rustc_data_structures/src/lib.rs

@@ -150,3 +150,14 @@ pub fn make_display(f: impl Fn(&mut fmt::Formatter<'_>) -> fmt::Result) -> impl
 // See comments in src/librustc_middle/lib.rs
 #[doc(hidden)]
 pub fn __noop_fix_for_27438() {}
+
+#[macro_export]
+macro_rules! external_bitflags_debug {
+    ($Name:ident) => {
+        impl ::std::fmt::Debug for $Name {
+            fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
+                ::bitflags::parser::to_writer(self, f)
+            }
+        }
+    };
+}