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Add a faq entry for the demo page

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10488 91177308-0d34-0410-b5e6-96231b3b80d8
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Chris Lattner 2003-12-16 22:33:55 +00:00
parent 0f7d2e8b8d
commit a28e3cea1c
1 changed files with 23 additions and 5 deletions
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docs/FAQ.html
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@ -70,6 +70,7 @@
<ol>
<li>What is this <tt>__main()</tt> call that gets inserted into
<tt>main()</tt>?</li>
<li>Where did all of my code go??</li>
</ol>
</li>
</ol>
@ -406,11 +407,9 @@ directory inside of the LLVM GCC distribution.
<a name="cfe_code">Questions about code generated by the GCC front-end</a>
</div>
<div class="question">
<p>
<div class="question"><p>
What is this <tt>__main()</tt> call that gets inserted into <tt>main()</tt>?
</p>
</div>
</p></div>
<div class="answer">
<p>
@ -426,10 +425,29 @@ The actual implementation of <tt>__main</tt> lives in the
<tt>llvm/runtime/GCCLibraries/crtend/</tt> directory in the source-base, and is
linked in automatically when you link the program.
</p>
</div>
<!--=========================================================================-->
<div class="question"><p>
Where did all of my code go??
</p></div>
<div class="answer">
<p>
If you are using the LLVM demo page, you may often wonder what happened to all
of the code that you typed in. Remember that the demo script is running the
code through the LLVM optimizers, so if you code doesn't actually do anything
useful, it might all be deleted.
</p>
<p>
To prevent this, make sure that the code is actually needed. For example, if
you are computing some expression, return the value from the function instead of
leaving it in a local variable. If you really want to constrain the optimizer,
you can read from and assign to <tt>volatile</tt> global variables.
</p>
</div>
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