Rollup merge of #126787 - Strophox:get-bytes, r=RalfJung

Add direct accessors for memory addresses in `Machine` (for Miri)

The purpose of this PR is to enable direct (immutable) access to memory addresses in `Machine`, which will be needed for further extension of Miri.

This is done by adding (/completing missings pairs of) accessor functions, with the relevant signatures as follows:
```rust
/* rust/compiler/rustc_middle/src/mir/interpret/allocation.rs */

pub trait AllocBytes {
  // ..

  fn as_ptr(&self) -> *const u8;
/*fn as_mut_ptr(&mut self) -> *mut u8; -- Already in the compiler*/
}

impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes> {
  // ..

  pub fn get_bytes_unchecked_raw(&self) -> *const u8;
/*pub fn get_bytes_unchecked_raw_mut(&mut self) -> *mut u8; -- Already in the compiler*/
}
```
```rust
/* rust/compiler/rustc_const_eval/src/interpret/memory.rs */

impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
  // ..

  pub fn get_alloc_bytes_unchecked_raw(&self, id: AllocId) -> InterpResult<'tcx, *const u8>;
  pub fn get_alloc_bytes_unchecked_raw_mut(&mut self, id: AllocId) -> InterpResult<'tcx, *mut u8>;
}
```

r? ``@RalfJung``

1 files changed, 17 insertions, 0 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index 9a26ac04b85..9d0c4908225 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -630,6 +630,13 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         }
     }
 
+    /// Gives raw, immutable access to the `Allocation` address, without bounds or alignment checks.
+    /// The caller is responsible for calling the access hooks!
+    pub fn get_alloc_bytes_unchecked_raw(&self, id: AllocId) -> InterpResult<'tcx, *const u8> {
+        let alloc = self.get_alloc_raw(id)?;
+        Ok(alloc.get_bytes_unchecked_raw())
+    }
+
     /// Bounds-checked *but not align-checked* allocation access.
     pub fn get_ptr_alloc<'a>(
         &'a self,
@@ -713,6 +720,16 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         Ok((alloc, &mut self.machine))
     }
 
+    /// Gives raw, mutable access to the `Allocation` address, without bounds or alignment checks.
+    /// The caller is responsible for calling the access hooks!
+    pub fn get_alloc_bytes_unchecked_raw_mut(
+        &mut self,
+        id: AllocId,
+    ) -> InterpResult<'tcx, *mut u8> {
+        let alloc = self.get_alloc_raw_mut(id)?.0;
+        Ok(alloc.get_bytes_unchecked_raw_mut())
+    }
+
     /// Bounds-checked *but not align-checked* allocation access.
     pub fn get_ptr_alloc_mut<'a>(
         &'a mut self,