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<h3 class="section">13.22 Reading RTL</h3>
<p>To read an RTL object from a file, call <code>read_rtx</code>. It takes one
argument, a stdio stream, and returns a single RTL object. This routine
is defined in <samp><span class="file">read-rtl.c</span></samp>. It is not available in the compiler
itself, only the various programs that generate the compiler back end
from the machine description.
<p>People frequently have the idea of using RTL stored as text in a file as
an interface between a language front end and the bulk of GCC. This
idea is not feasible.
<p>GCC was designed to use RTL internally only. Correct RTL for a given
program is very dependent on the particular target machine. And the RTL
does not contain all the information about the program.
<p>The proper way to interface GCC to a new language front end is with
the “tree” data structure, described in the files <samp><span class="file">tree.h</span></samp> and
<samp><span class="file">tree.def</span></samp>. The documentation for this structure (see <a href="GENERIC.html#GENERIC">GENERIC</a>)
is incomplete.
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