diff --git a/tools/llvm-objdump/llvm-objdump.h b/tools/llvm-objdump/llvm-objdump.h
index 1611516..aa71b77 100644
--- a/tools/llvm-objdump/llvm-objdump.h
+++ b/tools/llvm-objdump/llvm-objdump.h
@@ -31,9 +31,9 @@
   StringRefMemoryObject(StringRef bytes) : Bytes(bytes) {}
 
   uint64_t getBase() const { return 0; }
-  uint64_t getExtent() { return Bytes.size(); }
+  uint64_t getExtent() const { return Bytes.size(); }
 
-  int readByte(uint64_t Addr, uint8_t *Byte) {
+  int readByte(uint64_t Addr, uint8_t *Byte) const {
     if (Addr >= getExtent())
       return -1;
     *Byte = Bytes[Addr];