Make TypeId const comparable

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -175,6 +175,17 @@ pub(crate) fn codegen_const_value<'tcx>(
                             fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
                         fx.bcx.ins().global_value(fx.pointer_type, local_data_id)
                     }
+                    GlobalAlloc::Type { .. } => {
+                        let data_id = data_id_for_alloc_id(
+                            &mut fx.constants_cx,
+                            fx.module,
+                            alloc_id,
+                            Mutability::Not,
+                        );
+                        let local_data_id =
+                            fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
+                        fx.bcx.ins().global_value(fx.pointer_type, local_data_id)
+                    }
                     GlobalAlloc::Static(def_id) => {
                         assert!(fx.tcx.is_static(def_id));
                         let data_id = data_id_for_static(
@@ -360,6 +371,7 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut Constant
                     GlobalAlloc::Memory(alloc) => alloc,
                     GlobalAlloc::Function { .. }
                     | GlobalAlloc::Static(_)
+                    | GlobalAlloc::Type { .. }
                     | GlobalAlloc::VTable(..) => {
                         unreachable!()
                     }
@@ -471,6 +483,8 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut Constant
                         .principal()
                         .map(|principal| tcx.instantiate_bound_regions_with_erased(principal)),
                 ),
+                // TODO
+                GlobalAlloc::Type { .. } => todo!(),
                 GlobalAlloc::Static(def_id) => {
                     if tcx.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::THREAD_LOCAL)
                     {

compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs

@@ -812,7 +812,7 @@ fn codegen_regular_intrinsic_call<'tcx>(
             dest.write_cvalue(fx, val);
         }
 
-        sym::needs_drop | sym::type_id | sym::type_name | sym::variant_count => {
+        sym::needs_drop | sym::type_name | sym::variant_count => {
             intrinsic_args!(fx, args => (); intrinsic);
 
             let const_val = fx

compiler/rustc_codegen_gcc/src/common.rs

@@ -1,10 +1,10 @@
 use gccjit::{LValue, RValue, ToRValue, Type};
-use rustc_abi as abi;
-use rustc_abi::HasDataLayout;
 use rustc_abi::Primitive::Pointer;
+use rustc_abi::{self as abi, Align, HasDataLayout, Size};
 use rustc_codegen_ssa::traits::{
     BaseTypeCodegenMethods, ConstCodegenMethods, MiscCodegenMethods, StaticCodegenMethods,
 };
+use rustc_const_eval::interpret::{AllocInit, Allocation, alloc_range};
 use rustc_middle::mir::Mutability;
 use rustc_middle::mir::interpret::{ConstAllocation, GlobalAlloc, Scalar};
 use rustc_middle::ty::layout::LayoutOf;
@@ -303,6 +303,30 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> {
                         let init = self.const_data_from_alloc(alloc);
                         self.static_addr_of(init, alloc.inner().align, None)
                     }
+                    GlobalAlloc::Type { ty: type_id_ty, segment } => {
+                        let type_id = self.tcx.type_id_hash(type_id_ty).as_u128();
+                        let mut alloc: Allocation = Allocation::new(
+                            Size::from_bytes(16),
+                            Align::from_bytes(8).unwrap(),
+                            AllocInit::Uninit,
+                            (),
+                        );
+                        alloc
+                            .write_scalar(
+                                &self.tcx,
+                                alloc_range(Size::ZERO, Size::from_bytes(16)),
+                                Scalar::from_u128(type_id),
+                            )
+                            .unwrap();
+                        let pointer_size = self.tcx.data_layout.pointer_size;
+                        let offset = pointer_size * u64::from(segment);
+                        let value = alloc
+                            .read_scalar(&self.tcx, alloc_range(offset, pointer_size), false)
+                            .unwrap();
+                        let data = value.to_bits(pointer_size).unwrap() as u64;
+                        let val = self.const_usize(data);
+                        return self.context.new_cast(None, val, ty);
+                    }
                     GlobalAlloc::Static(def_id) => {
                         assert!(self.tcx.is_static(def_id));
                         self.get_static(def_id).get_address(None)

compiler/rustc_codegen_gcc/src/lib.rs

@@ -41,6 +41,7 @@ extern crate rustc_apfloat;
 extern crate rustc_ast;
 extern crate rustc_attr_data_structures;
 extern crate rustc_codegen_ssa;
+extern crate rustc_const_eval;
 extern crate rustc_data_structures;
 extern crate rustc_errors;
 extern crate rustc_fluent_macro;

compiler/rustc_codegen_llvm/src/common.rs

@@ -3,17 +3,18 @@
 use std::borrow::Borrow;
 
 use libc::{c_char, c_uint};
-use rustc_abi as abi;
-use rustc_abi::HasDataLayout;
 use rustc_abi::Primitive::Pointer;
+use rustc_abi::{self as abi, Align, HasDataLayout as _, Size};
 use rustc_ast::Mutability;
 use rustc_codegen_ssa::common::TypeKind;
 use rustc_codegen_ssa::traits::*;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_hashes::Hash128;
 use rustc_hir::def_id::DefId;
 use rustc_middle::bug;
-use rustc_middle::mir::interpret::{ConstAllocation, GlobalAlloc, Scalar};
+use rustc_middle::mir::interpret::{
+    AllocInit, Allocation, ConstAllocation, GlobalAlloc, Scalar, alloc_range,
+};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::cstore::DllImport;
 use tracing::debug;
@@ -284,7 +285,8 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> {
                                 self.const_bitcast(llval, llty)
                             };
                         } else {
-                            let init = const_alloc_to_llvm(self, alloc, /*static*/ false);
+                            let init =
+                                const_alloc_to_llvm(self, alloc.inner(), /*static*/ false);
                             let alloc = alloc.inner();
                             let value = match alloc.mutability {
                                 Mutability::Mut => self.static_addr_of_mut(init, alloc.align, None),
@@ -316,15 +318,38 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> {
                                 }),
                             )))
                             .unwrap_memory();
-                        let init = const_alloc_to_llvm(self, alloc, /*static*/ false);
-                        let value = self.static_addr_of_impl(init, alloc.inner().align, None);
-                        value
+                        let init = const_alloc_to_llvm(self, alloc.inner(), /*static*/ false);
+                        self.static_addr_of_impl(init, alloc.inner().align, None)
                     }
                     GlobalAlloc::Static(def_id) => {
                         assert!(self.tcx.is_static(def_id));
                         assert!(!self.tcx.is_thread_local_static(def_id));
                         self.get_static(def_id)
                     }
+                    GlobalAlloc::Type { ty, segment } => {
+                        let type_id = self.tcx.type_id_hash(ty).as_u128();
+                        let mut alloc: Allocation = Allocation::new(
+                            Size::from_bytes(16),
+                            Align::from_bytes(8).unwrap(),
+                            AllocInit::Uninit,
+                            (),
+                        );
+                        alloc
+                            .write_scalar(
+                                &self.tcx,
+                                alloc_range(Size::ZERO, Size::from_bytes(16)),
+                                Scalar::from_u128(type_id),
+                            )
+                            .unwrap();
+                        let pointer_size = self.tcx.data_layout.pointer_size;
+                        let offset = pointer_size * u64::from(segment);
+                        let value = alloc
+                            .read_scalar(&self.tcx, alloc_range(offset, pointer_size), false)
+                            .unwrap();
+                        let data = value.to_bits(pointer_size).unwrap() as u64;
+                        let llval = self.const_usize(data);
+                        return unsafe { llvm::LLVMConstIntToPtr(llval, llty) };
+                    }
                 };
                 let base_addr_space = global_alloc.address_space(self);
                 let llval = unsafe {
@@ -346,7 +371,7 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> {
     }
 
     fn const_data_from_alloc(&self, alloc: ConstAllocation<'_>) -> Self::Value {
-        const_alloc_to_llvm(self, alloc, /*static*/ false)
+        const_alloc_to_llvm(self, alloc.inner(), /*static*/ false)
     }
 
     fn const_ptr_byte_offset(&self, base_addr: Self::Value, offset: abi::Size) -> Self::Value {

compiler/rustc_codegen_llvm/src/consts.rs

@@ -27,10 +27,9 @@ use crate::{base, debuginfo};
 
 pub(crate) fn const_alloc_to_llvm<'ll>(
     cx: &CodegenCx<'ll, '_>,
-    alloc: ConstAllocation<'_>,
+    alloc: &Allocation,
     is_static: bool,
 ) -> &'ll Value {
-    let alloc = alloc.inner();
     // We expect that callers of const_alloc_to_llvm will instead directly codegen a pointer or
     // integer for any &ZST where the ZST is a constant (i.e. not a static). We should never be
     // producing empty LLVM allocations as they're just adding noise to binaries and forcing less
@@ -138,7 +137,7 @@ fn codegen_static_initializer<'ll, 'tcx>(
     def_id: DefId,
 ) -> Result<(&'ll Value, ConstAllocation<'tcx>), ErrorHandled> {
     let alloc = cx.tcx.eval_static_initializer(def_id)?;
-    Ok((const_alloc_to_llvm(cx, alloc, /*static*/ true), alloc))
+    Ok((const_alloc_to_llvm(cx, alloc.inner(), /*static*/ true), alloc))
 }
 
 fn set_global_alignment<'ll>(cx: &CodegenCx<'ll, '_>, gv: &'ll Value, mut align: Align) {

compiler/rustc_codegen_ssa/src/mir/intrinsic.rs

@@ -150,7 +150,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 }
                 value
             }
-            sym::needs_drop | sym::type_id | sym::type_name | sym::variant_count => {
+            sym::needs_drop | sym::type_name | sym::variant_count => {
                 let value = bx.tcx().const_eval_instance(bx.typing_env(), instance, span).unwrap();
                 OperandRef::from_const(bx, value, result.layout.ty).immediate_or_packed_pair(bx)
             }

compiler/rustc_codegen_ssa/src/mir/operand.rs

@@ -185,7 +185,7 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
         offset: Size,
     ) -> Self {
         let alloc_align = alloc.inner().align;
-        assert!(alloc_align >= layout.align.abi);
+        assert!(alloc_align >= layout.align.abi, "{alloc_align:?} < {:?}", layout.align.abi);
 
         let read_scalar = |start, size, s: abi::Scalar, ty| {
             match alloc.0.read_scalar(

compiler/rustc_const_eval/messages.ftl

@@ -78,6 +78,8 @@ const_eval_dealloc_kind_mismatch =
 
 const_eval_deref_function_pointer =
     accessing {$allocation} which contains a function
+const_eval_deref_typeid_pointer =
+    accessing {$allocation} which contains a `TypeId`
 const_eval_deref_vtable_pointer =
     accessing {$allocation} which contains a vtable
 const_eval_division_by_zero =

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -282,7 +282,9 @@ pub fn eval_to_const_value_raw_provider<'tcx>(
 ) -> ::rustc_middle::mir::interpret::EvalToConstValueResult<'tcx> {
     // We call `const_eval` for zero arg intrinsics, too, in order to cache their value.
     // Catch such calls and evaluate them instead of trying to load a constant's MIR.
-    if let ty::InstanceKind::Intrinsic(def_id) = key.value.instance.def {
+    if let ty::InstanceKind::Intrinsic(def_id) = key.value.instance.def
+        && key.value.promoted.is_none()
+    {
         let ty = key.value.instance.ty(tcx, key.typing_env);
         let ty::FnDef(_, args) = ty.kind() else {
             bug!("intrinsic with type {:?}", ty);

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -2,7 +2,7 @@ use std::borrow::{Borrow, Cow};
 use std::fmt;
 use std::hash::Hash;
 
-use rustc_abi::{Align, Size};
+use rustc_abi::{Align, FieldIdx, Size};
 use rustc_ast::Mutability;
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap, IndexEntry};
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -403,6 +403,37 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> {
                 let cmp = ecx.guaranteed_cmp(a, b)?;
                 ecx.write_scalar(Scalar::from_u8(cmp), dest)?;
             }
+            sym::type_id_eq => {
+                let a = ecx.project_field(&args[0], FieldIdx::ZERO)?;
+                let b = ecx.project_field(&args[1], FieldIdx::ZERO)?;
+                let mut eq = true;
+                for index in 0..(16 / ecx.tcx.data_layout.pointer_size.bytes()) {
+                    let a = ecx.project_index(&a, index)?;
+                    let a = ecx.deref_pointer(&a)?;
+                    let (a, offset) = a.ptr().into_parts();
+                    assert_eq!(offset, Size::ZERO);
+                    let a = a.unwrap().alloc_id();
+                    let GlobalAlloc::Type { ty: a, segment: a_segment } = ecx.tcx.global_alloc(a)
+                    else {
+                        bug!()
+                    };
+                    let b = ecx.project_index(&b, index)?;
+                    let b = ecx.deref_pointer(&b)?;
+                    let (b, offset) = b.ptr().into_parts();
+                    assert_eq!(offset, Size::ZERO);
+                    let b = b.unwrap().alloc_id();
+                    let GlobalAlloc::Type { ty: b, segment: b_segment } = ecx.tcx.global_alloc(b)
+                    else {
+                        bug!()
+                    };
+
+                    eq &= a == b && a_segment == b_segment;
+                    if !eq {
+                        break;
+                    }
+                }
+                ecx.write_scalar(Scalar::from_bool(eq), dest)?;
+            }
             sym::const_allocate => {
                 let size = ecx.read_scalar(&args[0])?.to_target_usize(ecx)?;
                 let align = ecx.read_scalar(&args[1])?.to_target_usize(ecx)?;

compiler/rustc_const_eval/src/errors.rs

@@ -488,6 +488,7 @@ impl<'a> ReportErrorExt for UndefinedBehaviorInfo<'a> {
             WriteToReadOnly(_) => const_eval_write_to_read_only,
             DerefFunctionPointer(_) => const_eval_deref_function_pointer,
             DerefVTablePointer(_) => const_eval_deref_vtable_pointer,
+            DerefTypeIdPointer(_) => const_eval_deref_typeid_pointer,
             InvalidBool(_) => const_eval_invalid_bool,
             InvalidChar(_) => const_eval_invalid_char,
             InvalidTag(_) => const_eval_invalid_tag,
@@ -601,7 +602,10 @@ impl<'a> ReportErrorExt for UndefinedBehaviorInfo<'a> {
                 diag.arg("has", has.bytes());
                 diag.arg("msg", format!("{msg:?}"));
             }
-            WriteToReadOnly(alloc) | DerefFunctionPointer(alloc) | DerefVTablePointer(alloc) => {
+            WriteToReadOnly(alloc)
+            | DerefFunctionPointer(alloc)
+            | DerefVTablePointer(alloc)
+            | DerefTypeIdPointer(alloc) => {
                 diag.arg("allocation", alloc);
             }
             InvalidBool(b) => {

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -6,7 +6,9 @@ use std::assert_matches::assert_matches;
 
 use rustc_abi::Size;
 use rustc_apfloat::ieee::{Double, Half, Quad, Single};
+use rustc_ast::Mutability;
 use rustc_hir::def_id::DefId;
+use rustc_middle::mir::interpret::{AllocId, AllocInit, alloc_range};
 use rustc_middle::mir::{self, BinOp, ConstValue, NonDivergingIntrinsic};
 use rustc_middle::ty::layout::{LayoutOf as _, TyAndLayout, ValidityRequirement};
 use rustc_middle::ty::{GenericArgsRef, Ty, TyCtxt};
@@ -30,6 +32,24 @@ pub(crate) fn alloc_type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ConstAll
     tcx.mk_const_alloc(alloc)
 }
 
+pub(crate) fn alloc_type_id<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> AllocId {
+    let size = Size::from_bytes(16);
+    let align = tcx.data_layout.pointer_align;
+    let mut alloc = Allocation::new(size, *align, AllocInit::Uninit, ());
+    let ptr_size = tcx.data_layout.pointer_size;
+    for step in 0..size.bytes() / ptr_size.bytes() {
+        let offset = ptr_size * step;
+        let alloc_id = tcx.reserve_and_set_type_id_alloc(ty, step.try_into().unwrap());
+        let ptr = Pointer::new(alloc_id.into(), Size::ZERO);
+        let val = Scalar::from_pointer(ptr, &tcx);
+        alloc.write_scalar(&tcx, alloc_range(offset, ptr_size), val).unwrap();
+    }
+
+    alloc.mutability = Mutability::Not;
+
+    tcx.reserve_and_set_memory_alloc(tcx.mk_const_alloc(alloc))
+}
+
 /// The logic for all nullary intrinsics is implemented here. These intrinsics don't get evaluated
 /// inside an `InterpCx` and instead have their value computed directly from rustc internal info.
 pub(crate) fn eval_nullary_intrinsic<'tcx>(
@@ -52,7 +72,8 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
         }
         sym::type_id => {
             ensure_monomorphic_enough(tcx, tp_ty)?;
-            ConstValue::from_u128(tcx.type_id_hash(tp_ty).as_u128())
+            let alloc_id = alloc_type_id(tcx, tp_ty);
+            ConstValue::Indirect { alloc_id, offset: Size::ZERO }
         }
         sym::variant_count => match match tp_ty.kind() {
             // Pattern types have the same number of variants as their base type.

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -346,6 +346,13 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                         kind = "vtable",
                     )
                 }
+                Some(GlobalAlloc::Type { .. }) => {
+                    err_ub_custom!(
+                        fluent::const_eval_invalid_dealloc,
+                        alloc_id = alloc_id,
+                        kind = "typeid",
+                    )
+                }
                 Some(GlobalAlloc::Static(..) | GlobalAlloc::Memory(..)) => {
                     err_ub_custom!(
                         fluent::const_eval_invalid_dealloc,
@@ -615,6 +622,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             }
             Some(GlobalAlloc::Function { .. }) => throw_ub!(DerefFunctionPointer(id)),
             Some(GlobalAlloc::VTable(..)) => throw_ub!(DerefVTablePointer(id)),
+            Some(GlobalAlloc::Type { .. }) => throw_ub!(DerefTypeIdPointer(id)),
             None => throw_ub!(PointerUseAfterFree(id, CheckInAllocMsg::MemoryAccess)),
             Some(GlobalAlloc::Static(def_id)) => {
                 assert!(self.tcx.is_static(def_id));
@@ -891,7 +899,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             let (size, align) = global_alloc.size_and_align(*self.tcx, self.typing_env);
             let mutbl = global_alloc.mutability(*self.tcx, self.typing_env);
             let kind = match global_alloc {
-                GlobalAlloc::Static { .. } | GlobalAlloc::Memory { .. } => AllocKind::LiveData,
+                GlobalAlloc::Type { .. }
+                | GlobalAlloc::Static { .. }
+                | GlobalAlloc::Memory { .. } => AllocKind::LiveData,
                 GlobalAlloc::Function { .. } => bug!("We already checked function pointers above"),
                 GlobalAlloc::VTable { .. } => AllocKind::VTable,
             };
@@ -1201,6 +1211,9 @@ impl<'a, 'tcx, M: Machine<'tcx>> std::fmt::Debug for DumpAllocs<'a, 'tcx, M> {
                         Some(GlobalAlloc::VTable(ty, dyn_ty)) => {
                             write!(fmt, " (vtable: impl {dyn_ty} for {ty})")?;
                         }
+                        Some(GlobalAlloc::Type { ty, segment }) => {
+                            write!(fmt, " (typeid segment {segment } for {ty})")?;
+                        }
                         Some(GlobalAlloc::Static(did)) => {
                             write!(fmt, " (static: {})", self.ecx.tcx.def_path_str(did))?;
                         }