diff --git a/src/SAWScript/HeapsterBuiltins.hs b/src/SAWScript/HeapsterBuiltins.hs
index ff2491c915..1900049dd8 100644
--- a/src/SAWScript/HeapsterBuiltins.hs
+++ b/src/SAWScript/HeapsterBuiltins.hs
@@ -40,6 +40,7 @@ module SAWScript.HeapsterBuiltins
        , heapster_find_trait_method_symbol
        , heapster_assume_fun
        , heapster_assume_fun_rename
+       , heapster_assume_fun_rename_prim
        , heapster_assume_fun_multi
        , heapster_print_fun_trans
        , heapster_export_coq
@@ -869,6 +870,53 @@ heapster_assume_fun_rename _bic _opts henv nm nm_to perms_string term_string =
                                            (globalOpenTerm term_ident)
         liftIO $ writeIORef (heapsterEnvPermEnvRef henv) env''
 
+-- | Create a new SAW core primitive named @nm@ with type @tp@ in the module
+-- associated with the supplied Heapster environment, and return its identifier
+insPrimitive :: HeapsterEnv -> String -> Term -> TopLevel Ident
+insPrimitive henv nm tp =
+  do sc <- getSharedContext
+     let mnm = heapsterEnvSAWModule henv
+     let ident = mkSafeIdent mnm nm
+     i <- liftIO $ scFreshGlobalVar sc
+     liftIO $ scRegisterName sc i (ModuleIdentifier ident)
+     let pn = PrimName i ident tp
+     t <- liftIO $ scFlatTermF sc (Primitive pn)
+     liftIO $ scRegisterGlobal sc ident t
+     liftIO $ scModifyModule sc mnm $ \m ->
+        insDef m $ Def { defIdent = ident,
+                         defQualifier = PrimQualifier,
+                         defType = tp,
+                         defBody = Nothing }
+     return ident
+
+-- | Assume that the given named function has the supplied type and translates
+-- to a SAW core definition given by the second name
+heapster_assume_fun_rename_prim :: BuiltinContext -> Options -> HeapsterEnv ->
+                              String -> String -> String -> TopLevel ()
+heapster_assume_fun_rename_prim _bic _opts henv nm nm_to perms_string =
+  do Some lm <- failOnNothing ("Could not find symbol: " ++ nm)
+                              (lookupModContainingSym henv nm)
+     sc <- getSharedContext
+     let w = llvmModuleArchReprWidth lm
+     leq_proof <- case decideLeq (knownNat @1) w of
+       Left pf -> return pf
+       Right _ -> fail "LLVM arch width is 0!"
+     env <- liftIO $ readIORef $ heapsterEnvPermEnvRef henv
+     (Some cargs, Some ret) <- lookupFunctionType lm nm
+     let args = mkCruCtx cargs
+     withKnownNat w $ withLeqProof leq_proof $ do
+        SomeFunPerm fun_perm <-
+          parseFunPermStringMaybeRust "permissions" w env args ret perms_string
+        env' <- liftIO $ readIORef (heapsterEnvPermEnvRef henv)
+        fun_typ <- liftIO $ translateCompleteFunPerm sc env fun_perm
+        term_ident <- insPrimitive henv nm_to fun_typ
+        let env'' = permEnvAddGlobalSymFun env'
+                                           (GlobalSymbol $ fromString nm)
+                                           w
+                                           fun_perm
+                                           (globalOpenTerm term_ident)
+        liftIO $ writeIORef (heapsterEnvPermEnvRef henv) env''
+
 -- | Assume that the given named function has the supplied type and translates
 -- to a SAW core definition given by name
 heapster_assume_fun :: BuiltinContext -> Options -> HeapsterEnv ->
diff --git a/src/SAWScript/Interpreter.hs b/src/SAWScript/Interpreter.hs
index fc2b49e190..aa0b8de25d 100644
--- a/src/SAWScript/Interpreter.hs
+++ b/src/SAWScript/Interpreter.hs
@@ -3187,6 +3187,15 @@ primitives = Map.fromList
     , " trans is not an identifier then it is bound to the defined name nm_to."
     ]
 
+  , prim "heapster_assume_fun_rename_prim"
+    "HeapsterEnv -> String -> String -> String -> TopLevel HeapsterEnv"
+    (bicVal heapster_assume_fun_rename_prim)
+    Experimental
+    [
+      "heapster_assume_fun_rename_prim nm nm_to perms assumes that function nm"
+    , " has permissions perms as a primitive."
+    ]
+
   , prim "heapster_assume_fun_multi"
     "HeapsterEnv -> String -> [(String, String)] -> TopLevel HeapsterEnv"
     (bicVal heapster_assume_fun_multi)