Rollup merge of rust-lang#114466 - ouz-a:smir_allocation, r=oli-obk

Add Allocation to SMIR

As it's discussed [here ](https://rust-lang.zulipchat.com/#narrow/stream/320896-project-stable-mir/topic/Representing.20Constants.20in.20smir)this is an attempt to cover Constants for smir in a different way compared to rust-lang#114342

cc rust-lang/project-stable-mir#15

r? `@oli-obk`

Author: matthiaskrgr

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -1063,3 +1063,34 @@ impl<'tcx> Stable<'tcx> for rustc_middle::ty::BoundTy {
         BoundTy { var: self.var.as_usize(), kind: self.kind.stable(tables) }
     }
 }
+
+impl<'tcx> Stable<'tcx> for mir::interpret::Allocation {
+    type T = stable_mir::ty::Allocation;
+
+    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+        let size = self.size();
+        let mut bytes: Vec<Option<u8>> = self
+            .inspect_with_uninit_and_ptr_outside_interpreter(0..size.bytes_usize())
+            .iter()
+            .copied()
+            .map(Some)
+            .collect();
+        for (i, b) in bytes.iter_mut().enumerate() {
+            if !self.init_mask().get(rustc_target::abi::Size::from_bytes(i)) {
+                *b = None;
+            }
+        }
+        stable_mir::ty::Allocation {
+            bytes: bytes,
+            provenance: {
+                let mut ptrs = Vec::new();
+                for (size, prov) in self.provenance().ptrs().iter() {
+                    ptrs.push((size.bytes_usize(), opaque(prov)));
+                }
+                stable_mir::ty::ProvenanceMap { ptrs }
+            },
+            align: self.align.bytes(),
+            mutability: self.mutability.stable(tables),
+        }
+    }
+}

compiler/rustc_smir/src/stable_mir/ty.rs

@@ -242,3 +242,25 @@ pub struct BoundTy {
     pub var: usize,
     pub kind: BoundTyKind,
 }
+
+pub type Bytes = Vec<Option<u8>>;
+pub type Size = usize;
+pub type Prov = Opaque;
+pub type Align = u64;
+pub type InitMaskMaterialized = Vec<u64>;
+
+/// Stores the provenance information of pointers stored in memory.
+#[derive(Clone, Debug)]
+pub struct ProvenanceMap {
+    /// Provenance in this map applies from the given offset for an entire pointer-size worth of
+    /// bytes. Two entries in this map are always at least a pointer size apart.
+    pub ptrs: Vec<(Size, Prov)>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Allocation {
+    pub bytes: Bytes,
+    pub provenance: ProvenanceMap,
+    pub align: Align,
+    pub mutability: Mutability,
+}