Add allocate_bytes and refactor allocate_str in InterpCx for raw byte allocation

Signed-off-by: shamb0 <[email protected]>

Author: shamb0

compiler/rustc_const_eval/src/interpret/place.rs

@@ -1018,31 +1018,53 @@ where
         self.allocate_dyn(layout, kind, MemPlaceMeta::None)
     }
 
-    /// Returns a wide MPlace of type `str` to a new 1-aligned allocation.
-    /// Immutable strings are deduplicated and stored in global memory.
-    pub fn allocate_str(
+    /// Allocates a sequence of bytes in the interpreter's memory.
+    /// For immutable allocations, uses deduplication to reuse existing memory.
+    /// For mutable allocations, creates a new unique allocation.
+    pub fn allocate_bytes(
         &mut self,
-        str: &str,
+        bytes: &[u8],
+        align: Align,
         kind: MemoryKind<M::MemoryKind>,
         mutbl: Mutability,
     ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> {
-        let tcx = self.tcx.tcx;
-
-        // Use cache for immutable strings.
         let ptr = if mutbl.is_not() {
-            // Use dedup'd allocation function.
+            // Deduplicate immutable allocations using a salted hash
             let salt = M::get_global_alloc_salt(self, None);
-            let id = tcx.allocate_bytes_dedup(str.as_bytes(), salt);
+            let id = self.tcx.allocate_bytes_dedup(bytes, salt);
 
-            // Turn untagged "global" pointers (obtained via `tcx`) into the machine pointer to the allocation.
+            // Transform allocation ID to a machine-specific pointer with proper provenance
             M::adjust_alloc_root_pointer(&self, Pointer::from(id), Some(kind))?
         } else {
-            self.allocate_bytes_ptr(str.as_bytes(), Align::ONE, kind, mutbl)?
+            // Allocate new memory for mutable data
+            self.allocate_bytes_ptr(bytes, align, kind, mutbl)?
         };
-        let meta = Scalar::from_target_usize(u64::try_from(str.len()).unwrap(), self);
+
+        let layout = self.layout_of(self.tcx.types.u8).unwrap();
+
+        interp_ok(self.ptr_to_mplace(ptr.into(), layout))
+    }
+
+    /// Allocates a string in the interpreter's memory with metadata for length.
+    /// Uses `allocate_bytes` internally but adds string-specific metadata handling.
+    pub fn allocate_str(
+        &mut self,
+        str: &str,
+        kind: MemoryKind<M::MemoryKind>,
+        mutbl: Mutability,
+    ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> {
+        let bytes = str.as_bytes();
+        let mplace_type = self.allocate_bytes(bytes, Align::ONE, kind, mutbl)?;
+
+        // Create length metadata for the string
+        let meta = Scalar::from_target_usize(u64::try_from(bytes.len()).unwrap(), self);
+
+        // Get layout for Rust's str type
         let layout = self.layout_of(self.tcx.types.str_).unwrap();
+
+        // Combine pointer and metadata into a wide pointer
         interp_ok(self.ptr_with_meta_to_mplace(
-            ptr.into(),
+            mplace_type.ptr().into(),
             MemPlaceMeta::Meta(meta),
             layout,
             /*unaligned*/ false,