Added invalid memory access example

manuscript/code/symbolic/invalid-memory-access.c

@@ -0,0 +1,29 @@
+/*
+The purpose of this code is to demonstrate the capabilities
+of the monster model generator of selfie. Monster translates
+the code to an SMT-LIB or BTOR2 formula that is satisfiable
+if and only if the code exits with a non-zero exit code, or
+performs division by zero or invalid/unsafe memory accesses.
+
+Input == #b00110001 (== 49 == '1')
+*/
+
+uint64_t main() {
+  uint64_t  a;
+  uint64_t* x;
+
+  x = malloc(8);
+
+  read(1, x, 1);
+
+  if (*x == 48)
+    // address outside of virtual address space -> invalid memory access
+    *(x + 4294967296) = 0;
+
+  a = *x - 7;
+
+  if (a == 42)
+    return 1;
+  else
+    return 0;
+}