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Diffstat (limited to 'docs/FAQ.html')
| -rw-r--r-- | docs/FAQ.html | 28 |
1 files changed, 23 insertions, 5 deletions
diff --git a/docs/FAQ.html b/docs/FAQ.html index 79d2112c58..cc5d91c06a 100644 --- a/docs/FAQ.html +++ b/docs/FAQ.html @@ -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> <!-- *********************************************************************** --> <!-- *********************************************************************** --> |