\documentclass{article}

\usepackage{hyperref}

\let\oldhypertarget\hypertarget
\renewcommand{\hypertarget}[2]{%
  \label{ht@#1}% Set a \label
  \oldhypertarget{#1}{#2}% Set regular \hypertarget
}
\let\oldhyperlink\hyperlink
\renewcommand{\hyperlink}[2]{%
  \ifcsname r@ht@#1\endcsname
    \oldhyperlink{#1}{#2}% \hypertarget exists
  \else
    #2% \hypertarget doesn't exist
  \fi
}

\begin{document}

\hyperlink{link}{text1}

\hypertarget{link}{text2}

\hyperlink{link2}{text3}

\end{document}