diff --git a/include/verilated_dpi.cpp b/include/verilated_dpi.cpp
index 7f68e1bad..a9c1b3aed 100644
--- a/include/verilated_dpi.cpp
+++ b/include/verilated_dpi.cpp
@@ -181,7 +181,7 @@ void svPutPartselLogic(svLogicVecVal* dp, const svLogicVecVal s, int lbit, int w
 //======================================================================
 // Open array internals
 
-static const VerilatedDpiOpenVar* _vl_openhandle_varp(const svOpenArrayHandle h) {
+static const VerilatedDpiOpenVar* _vl_openhandle_varp(const svOpenArrayHandle h) VL_MT_SAFE {
     if (VL_UNLIKELY(!h)) {
         VL_FATAL_MT(__FILE__, __LINE__, "",
                     "%%Error: DPI svOpenArrayHandle function called with nullptr handle");
@@ -223,7 +223,7 @@ int svSizeOfArray(const svOpenArrayHandle h) {
 // Open array access internals
 
 static void* _vl_sv_adjusted_datap(const VerilatedDpiOpenVar* varp, int nargs, int indx1,
-                                   int indx2, int indx3) {
+                                   int indx2, int indx3) VL_MT_SAFE {
     void* datap = varp->datap();
     if (VL_UNLIKELY(nargs != varp->udims())) {
         VL_SVDPI_WARN_("%%Warning: DPI svOpenArrayHandle function called on"
diff --git a/include/verilated_sym_props.h b/include/verilated_sym_props.h
index c62d59faa..03228467f 100644
--- a/include/verilated_sym_props.h
+++ b/include/verilated_sym_props.h
@@ -53,14 +53,14 @@ public:
         : m_left{left}
         , m_right{right} {}
     ~VerilatedRange() = default;
-    int left() const { return m_left; }
-    int right() const { return m_right; }
-    int low() const { return (m_left < m_right) ? m_left : m_right; }
-    int high() const { return (m_left > m_right) ? m_left : m_right; }
-    int elements() const {
+    int left() const VL_PURE { return m_left; }
+    int right() const VL_PURE { return m_right; }
+    int low() const VL_PURE { return (m_left < m_right) ? m_left : m_right; }
+    int high() const VL_PURE { return (m_left > m_right) ? m_left : m_right; }
+    int elements() const VL_PURE {
         return (VL_LIKELY(m_left >= m_right) ? (m_left - m_right + 1) : (m_right - m_left + 1));
     }
-    int increment() const { return (m_left >= m_right) ? 1 : -1; }
+    int increment() const VL_PURE { return (m_left >= m_right) ? 1 : -1; }
 };
 
 //===========================================================================