From 005df5fe03ba2f9cdb7ed58d7cfb2c194184cc28 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Wed, 28 Nov 2018 09:22:02 +0100
Subject: [PATCH] provide a way to replace the tag in a Scalar/MemPlace

---
 src/librustc/mir/interpret/value.rs |  8 ++++++++
 src/librustc_mir/interpret/place.rs | 20 ++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/src/librustc/mir/interpret/value.rs b/src/librustc/mir/interpret/value.rs
index 4bcba9d54674..500bd47dfbe7 100644
--- a/src/librustc/mir/interpret/value.rs
+++ b/src/librustc/mir/interpret/value.rs
@@ -138,6 +138,14 @@ impl<'tcx, Tag> Scalar<Tag> {
         }
     }
 
+    #[inline]
+    pub fn with_tag(self, new_tag: Tag) -> Self {
+        match self {
+            Scalar::Ptr(ptr) => Scalar::Ptr(Pointer { tag: new_tag, ..ptr }),
+            Scalar::Bits { bits, size } => Scalar::Bits { bits, size },
+        }
+    }
+
     #[inline]
     pub fn ptr_null(cx: &impl HasDataLayout) -> Self {
         Scalar::Bits {
diff --git a/src/librustc_mir/interpret/place.rs b/src/librustc_mir/interpret/place.rs
index 1b47530eaec6..164a9680c797 100644
--- a/src/librustc_mir/interpret/place.rs
+++ b/src/librustc_mir/interpret/place.rs
@@ -115,6 +115,16 @@ impl<Tag> MemPlace<Tag> {
         }
     }
 
+    #[inline]
+    pub fn with_tag(self, new_tag: Tag) -> Self
+    {
+        MemPlace {
+            ptr: self.ptr.with_tag(new_tag),
+            align: self.align,
+            meta: self.meta,
+        }
+    }
+
     #[inline(always)]
     pub fn from_scalar_ptr(ptr: Scalar<Tag>, align: Align) -> Self {
         MemPlace {
@@ -187,6 +197,16 @@ impl<'tcx, Tag> MPlaceTy<'tcx, Tag> {
         }
     }
 
+    #[inline]
+    pub fn with_tag(self, new_tag: Tag) -> Self
+    {
+        MPlaceTy {
+            mplace: self.mplace.with_tag(new_tag),
+            layout: self.layout,
+        }
+    }
+
+    #[inline]
     pub fn offset(
         self,
         offset: Size,