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discourage else after "noreturn" statements. 

llvm-svn: 77387
This commit is contained in:
Chris Lattner 2009-07-28 22:54:04 +00:00
parent a58b3af802
commit 14abb832b2
1 changed files with 84 additions and 0 deletions
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llvm/docs/CodingStandards.html
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@ -43,6 +43,8 @@
Private</a></li>
<li><a href="#hl_earlyexit">Use Early Exits and 'continue' to Simplify
Code</a></li>
<li><a href="#hl_else_after_return">Don't use "else" after a
return</a></li>
<li><a href="#hl_predicateloops">Turn Predicate Loops into Predicate
Functions</a></li>
</ol></li>
@ -624,6 +626,88 @@ be a big understandability win.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="hl_else_after_return">Don't use "else" after a return</a>
</div>
<div class="doc_text">
<p>For similar reasons above (reduction of indentation and easier reading),
please do not use "else" or "else if" after something that interrupts
control flow like return, break, continue, goto, etc. For example, this is
"bad":</p>
<div class="doc_code">
<pre>
case 'J': {
if (Signed) {
Type = Context.getsigjmp_bufType();
if (Type.isNull()) {
Error = ASTContext::GE_Missing_sigjmp_buf;
return QualType();
} else {
break;
}
} else {
Type = Context.getjmp_bufType();
if (Type.isNull()) {
Error = ASTContext::GE_Missing_jmp_buf;
return QualType();
} else {
break;
}
}
}
}
</pre>
</div>
<p>It is better to write this something like:</p>
<div class="doc_code">
<pre>
case 'J':
if (Signed) {
Type = Context.getsigjmp_bufType();
if (Type.isNull()) {
Error = ASTContext::GE_Missing_sigjmp_buf;
return QualType();
}
} else {
Type = Context.getjmp_bufType();
if (Type.isNull()) {
Error = ASTContext::GE_Missing_jmp_buf;
return QualType();
}
}
break;
</pre>
</div>
<p>Or better yet (in this case), as:</p>
<div class="doc_code">
<pre>
case 'J':
if (Signed)
Type = Context.getsigjmp_bufType();
else
Type = Context.getjmp_bufType();
if (Type.isNull()) {
Error = Signed ? ASTContext::GE_Missing_sigjmp_buf :
ASTContext::GE_Missing_jmp_buf;
return QualType();
}
break;
</pre>
</div>
<p>The idea is to reduce indentation and the amount of code you have to keep
track of when reading the code.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">