title: How to find the git hash for an svn revision when git mirror of an svn repo is used?
body: <p>I would like to use git when experimenting with llvm and clang code.
  Therefore I already cloned the source files from the git mirror:</p>
  
  <pre><code>% git clone http://llvm.org/git/llvm.git
  % cd llvm/tools
  % git clone http://llvm.org/git/clang.git
  </code></pre>
  
  <p>Now I would like to use 3.4.2 as a base of my work. 
  I've found that it is svn Revision 216818 for <a href="http://llvm.org/svn/llvm-project/llvm/tags/RELEASE_342/final/" rel="nofollow">llvm</a> and for <a href="http://llvm.org/svn/llvm-project/cfe/tags/RELEASE_342/final/" rel="nofollow">clang</a>. But I am lost how to find the appropriate git hash for that so I could do this:</p>
  
  <pre><code>% git checkout -b myexperiment githash_of_svnrelease_342_final_of_LLVM
  % cd tools/clang
  % git checkout -b myexperiment githash_of_svnrelease_342_final_of_CLANG
  </code></pre>