Fix a copy+pasto in an assertion string.

[oota-llvm.git] / docs / CodingStandards.html

diff --git a/docs/CodingStandards.html b/docs/CodingStandards.html
index 3a7f8b3d1e9a33fd49c2f90f2ad53c4df070c216..04ce54fde47fbe193db1a660a20b02819d27226c 100644 (file)
--- a/docs/CodingStandards.html
+++ b/docs/CodingStandards.html
@@ -262,6 +262,18 @@ implements are defined.</p>
 like to print out code and look at your code in an xterm without resizing
 it.</p>
 
+<p>The longer answer is that there must be some limit to the width of the code
+in order to reasonably allow developers to have multiple files side-by-side in
+windows on a modest display.  If you are going to pick a width limit, it is
+somewhat arbitrary but you might as well pick something standard.  Going with
+90 columns (for example) instead of 80 columns wouldn't add any significant 
+value and would be detrimental to printing out code.  Also many other projects
+have standardized on 80 columns, so some people have already configured their
+editors for it (vs something else, like 90 columns).</p>
+
+<p>This is one of many contentious issues in coding standards, but is not up
+for debate.</p>
+
 </div>
 
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@@ -623,6 +635,29 @@ assert(isa&lt;PHINode&gt;(Succ-&gt;front()) &amp;&amp; "Only works on PHId BBs!"
 
 <p>You get the idea...</p>
 
+<p>Please be aware when adding assert statements that not all compilers are aware of
+the semantics of the assert.  In some places, asserts are used to indicate a piece of
+code that should not be reached.  These are typically of the form:</p>
+
+<div class="doc_code">
+<pre>
+assert(0 && "Some helpful error message");
+</pre>
+</div>
+
+<p>When used in a function that returns a value, they should be followed with a return
+statement and a comment indicating that this line is never reached.  This will prevent
+a compiler which is unable to deduce that the assert statement never returns from
+generating a warning.</p>
+
+<div class="doc_code">
+<pre>
+assert(0 && "Some helpful error message");
+// Not reached
+return 0;
+</pre>
+</div>
+
 </div>
 
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