move intrinsic to CTFE, add FIXME

Author: vn-ki

Diff for: compiler/rustc_mir/src/const_eval/machine.rs

@@ -13,6 +13,7 @@ use rustc_hir::def_id::DefId;
 use rustc_middle::mir::AssertMessage;
 use rustc_session::Limit;
 use rustc_span::symbol::{sym, Symbol};
+use rustc_target::abi::{Align, Size};
 
 use crate::interpret::{
     self, compile_time_machine, AllocId, Allocation, Frame, GlobalId, ImmTy, InterpCx,
@@ -304,6 +305,22 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
                 };
                 ecx.write_scalar(Scalar::from_bool(cmp), dest)?;
             }
+            sym::const_allocate => {
+                let size = ecx.read_scalar(args[0])?.to_machine_usize(ecx)?;
+                let align = ecx.read_scalar(args[1])?.to_machine_usize(ecx)?;
+
+                let align = match Align::from_bytes(align) {
+                    Ok(a) => a,
+                    Err(err) => throw_ub_format!("align has to be a power of 2, {}", err),
+                };
+
+                let ptr = ecx.memory.allocate(
+                    Size::from_bytes(size as u64),
+                    align,
+                    interpret::MemoryKind::ConstHeap,
+                );
+                ecx.write_scalar(Scalar::Ptr(ptr), dest)?;
+            }
             _ => {
                 return Err(ConstEvalErrKind::NeedsRfc(format!(
                     "calling intrinsic `{}`",

Diff for: compiler/rustc_mir/src/interpret/intrinsics.rs

@@ -14,11 +14,10 @@ use rustc_middle::ty;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_span::symbol::{sym, Symbol};
-use rustc_target::abi::{Abi, Align, LayoutOf as _, Primitive, Size};
+use rustc_target::abi::{Abi, LayoutOf as _, Primitive, Size};
 
 use super::{
-    util::ensure_monomorphic_enough, CheckInAllocMsg, ImmTy, InterpCx, Machine, MemoryKind, OpTy,
-    PlaceTy,
+    util::ensure_monomorphic_enough, CheckInAllocMsg, ImmTy, InterpCx, Machine, OpTy, PlaceTy,
 };
 
 mod caller_location;
@@ -338,22 +337,6 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let result = Scalar::from_uint(truncated_bits, layout.size);
                 self.write_scalar(result, dest)?;
             }
-            sym::const_allocate => {
-                let size = self.read_scalar(args[0])?.to_machine_usize(self)?;
-                let align = self.read_scalar(args[1])?.to_machine_usize(self)?;
-
-                let align = match Align::from_bytes(align) {
-                    Ok(a) => a,
-                    Err(err) => throw_ub_format!("align has to be a power of 2, {}", err),
-                };
-
-                let ptr = self.memory.allocate(
-                    Size::from_bytes(size as u64),
-                    align,
-                    MemoryKind::ConstHeap,
-                );
-                self.write_scalar(Scalar::Ptr(ptr), dest)?;
-            }
             sym::offset => {
                 let ptr = self.read_scalar(args[0])?.check_init()?;
                 let offset_count = self.read_scalar(args[1])?.to_machine_isize(self)?;

Diff for: compiler/rustc_mir/src/interpret/memory.rs

@@ -28,6 +28,7 @@ pub enum MemoryKind<T> {
     /// Stack memory. Error if deallocated except during a stack pop.
     Stack,
     /// Heap memory.
+    /// FIXME: this variant should be in const_eval
     ConstHeap,
     /// Memory backing vtables. Error if ever deallocated.
     Vtable,