Rollup merge of #143140 - RalfJung:ptr-into-parts, r=oli-obk

give Pointer::into_parts a more scary name and offer a safer alternative

`into_parts` is a bit too innocent of a name for a somewhat subtle operation.
r? `@oli-obk`

Author: matthiaskrgr

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -133,7 +133,7 @@ pub(crate) fn codegen_const_value<'tcx>(
                 }
             }
             Scalar::Ptr(ptr, _size) => {
-                let (prov, offset) = ptr.into_parts(); // we know the `offset` is relative
+                let (prov, offset) = ptr.prov_and_relative_offset();
                 let alloc_id = prov.alloc_id();
                 let base_addr = match fx.tcx.global_alloc(alloc_id) {
                     GlobalAlloc::Memory(alloc) => {

compiler/rustc_codegen_gcc/src/common.rs

@@ -248,7 +248,7 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> {
                 }
             }
             Scalar::Ptr(ptr, _size) => {
-                let (prov, offset) = ptr.into_parts(); // we know the `offset` is relative
+                let (prov, offset) = ptr.prov_and_relative_offset();
                 let alloc_id = prov.alloc_id();
                 let base_addr = match self.tcx.global_alloc(alloc_id) {
                     GlobalAlloc::Memory(alloc) => {

compiler/rustc_codegen_llvm/src/common.rs

@@ -268,7 +268,7 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> {
                 }
             }
             Scalar::Ptr(ptr, _size) => {
-                let (prov, offset) = ptr.into_parts();
+                let (prov, offset) = ptr.prov_and_relative_offset();
                 let global_alloc = self.tcx.global_alloc(prov.alloc_id());
                 let base_addr = match global_alloc {
                     GlobalAlloc::Memory(alloc) => {

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -209,9 +209,9 @@ pub(super) fn op_to_const<'tcx>(
 
     match immediate {
         Left(ref mplace) => {
-            // We know `offset` is relative to the allocation, so we can use `into_parts`.
-            let (prov, offset) = mplace.ptr().into_parts();
-            let alloc_id = prov.expect("cannot have `fake` place for non-ZST type").alloc_id();
+            let (prov, offset) =
+                mplace.ptr().into_pointer_or_addr().unwrap().prov_and_relative_offset();
+            let alloc_id = prov.alloc_id();
             ConstValue::Indirect { alloc_id, offset }
         }
         // see comment on `let force_as_immediate` above
@@ -232,9 +232,10 @@ pub(super) fn op_to_const<'tcx>(
                     imm.layout.ty,
                 );
                 let msg = "`op_to_const` on an immediate scalar pair must only be used on slice references to the beginning of an actual allocation";
-                // We know `offset` is relative to the allocation, so we can use `into_parts`.
-                let (prov, offset) = a.to_pointer(ecx).expect(msg).into_parts();
-                let alloc_id = prov.expect(msg).alloc_id();
+                let ptr = a.to_pointer(ecx).expect(msg);
+                let (prov, offset) =
+                    ptr.into_pointer_or_addr().expect(msg).prov_and_relative_offset();
+                let alloc_id = prov.alloc_id();
                 let data = ecx.tcx.global_alloc(alloc_id).unwrap_memory();
                 assert!(offset == abi::Size::ZERO, "{}", msg);
                 let meta = b.to_target_usize(ecx).expect(msg);

compiler/rustc_const_eval/src/errors.rs

@@ -574,7 +574,7 @@ impl<'a> ReportErrorExt for UndefinedBehaviorInfo<'a> {
                 if addr != 0 {
                     diag.arg(
                         "pointer",
-                        Pointer::<Option<CtfeProvenance>>::from_addr_invalid(addr).to_string(),
+                        Pointer::<Option<CtfeProvenance>>::without_provenance(addr).to_string(),
                     );
                 }
 

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -747,7 +747,7 @@ pub macro compile_time_machine(<$tcx: lifetime>) {
         // Allow these casts, but make the pointer not dereferenceable.
         // (I.e., they behave like transmutation.)
         // This is correct because no pointers can ever be exposed in compile-time evaluation.
-        interp_ok(Pointer::from_addr_invalid(addr))
+        interp_ok(Pointer::without_provenance(addr))
     }
 
     #[inline(always)]
@@ -756,8 +756,7 @@ pub macro compile_time_machine(<$tcx: lifetime>) {
         ptr: Pointer<CtfeProvenance>,
         _size: i64,
     ) -> Option<(AllocId, Size, Self::ProvenanceExtra)> {
-        // We know `offset` is relative to the allocation, so we can use `into_parts`.
-        let (prov, offset) = ptr.into_parts();
+        let (prov, offset) = ptr.prov_and_relative_offset();
         Some((prov.alloc_id(), offset, prov.immutable()))
     }
 

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -1596,7 +1596,8 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 Some((alloc_id, offset, extra)) => Ok((alloc_id, offset, extra)),
                 None => {
                     assert!(M::Provenance::OFFSET_IS_ADDR);
-                    let (_, addr) = ptr.into_parts();
+                    // Offset is absolute, as we just asserted.
+                    let (_, addr) = ptr.into_raw_parts();
                     Err(addr.bytes())
                 }
             },

compiler/rustc_const_eval/src/interpret/place.rs

@@ -118,7 +118,7 @@ impl<'tcx, Prov: Provenance> MPlaceTy<'tcx, Prov> {
     pub fn fake_alloc_zst(layout: TyAndLayout<'tcx>) -> Self {
         assert!(layout.is_zst());
         let align = layout.align.abi;
-        let ptr = Pointer::from_addr_invalid(align.bytes()); // no provenance, absolute address
+        let ptr = Pointer::without_provenance(align.bytes()); // no provenance, absolute address
         MPlaceTy { mplace: MemPlace { ptr, meta: MemPlaceMeta::None, misaligned: None }, layout }
     }
 

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -518,7 +518,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
             Ub(DanglingIntPointer { addr: i, .. }) => DanglingPtrNoProvenance {
                 ptr_kind,
                 // FIXME this says "null pointer" when null but we need translate
-                pointer: format!("{}", Pointer::<Option<AllocId>>::from_addr_invalid(i))
+                pointer: format!("{}", Pointer::<Option<AllocId>>::without_provenance(i))
             },
             Ub(PointerOutOfBounds { .. }) => DanglingPtrOutOfBounds {
                 ptr_kind
@@ -868,7 +868,9 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
     fn add_data_range(&mut self, ptr: Pointer<Option<M::Provenance>>, size: Size) {
         if let Some(data_bytes) = self.data_bytes.as_mut() {
             // We only have to store the offset, the rest is the same for all pointers here.
-            let (_prov, offset) = ptr.into_parts();
+            // The logic is agnostic to wether the offset is relative or absolute as long as
+            // it is consistent.
+            let (_prov, offset) = ptr.into_raw_parts();
             // Add this.
             data_bytes.add_range(offset, size);
         };
@@ -894,7 +896,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
             .as_mplace_or_imm()
             .expect_left("place must be in memory")
             .ptr();
-        let (_prov, offset) = ptr.into_parts();
+        let (_prov, offset) = ptr.into_raw_parts();
         offset
     }
 
@@ -903,7 +905,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
         // Our value must be in memory, otherwise we would not have set up `data_bytes`.
         let mplace = self.ecx.force_allocation(place)?;
         // Determine starting offset and size.
-        let (_prov, start_offset) = mplace.ptr().into_parts();
+        let (_prov, start_offset) = mplace.ptr().into_raw_parts();
         let (size, _align) = self
             .ecx
             .size_and_align_of_val(&mplace)?

compiler/rustc_middle/src/mir/consts.rs

@@ -168,8 +168,9 @@ impl<'tcx> ConstValue<'tcx> {
                     return Some(&[]);
                 }
                 // Non-empty slice, must have memory. We know this is a relative pointer.
-                let (inner_prov, offset) = ptr.into_parts();
-                let data = tcx.global_alloc(inner_prov?.alloc_id()).unwrap_memory();
+                let (inner_prov, offset) =
+                    ptr.into_pointer_or_addr().ok()?.prov_and_relative_offset();
+                let data = tcx.global_alloc(inner_prov.alloc_id()).unwrap_memory();
                 (data, offset.bytes(), offset.bytes() + len)
             }
         };