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Try to clarify a little how exception handling works. 

llvm-svn: 148136
This commit is contained in:
Duncan Sands 2012-01-13 19:59:16 +00:00
parent d7d5790cb6
commit df9d781510
1 changed files with 8 additions and 4 deletions
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12
llvm/docs/LangRef.html
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@ -6179,8 +6179,8 @@ freestanding environments and non-C-based languages.</p>
<h5>Syntax:</h5>
<pre>
&lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
&lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
&lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
&lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
&lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
&lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
@ -6194,7 +6194,7 @@ freestanding environments and non-C-based languages.</p>
<i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
defines values supplied by the personality function (<tt>pers_fn</tt>) upon
re-entry to the function. The <tt>resultval</tt> has the
type <tt>somety</tt>.</p>
type <tt>resultty</tt>.</p>
<h5>Arguments:</h5>
<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
@ -6218,7 +6218,11 @@ freestanding environments and non-C-based languages.</p>
<p>The clauses are applied in order from top to bottom. If two
<tt>landingpad</tt> instructions are merged together through inlining, the
clauses from the calling function are appended to the list of clauses.</p>
clauses from the calling function are appended to the list of clauses.
When the call stack is being unwound due to an exception being thrown, the
exception is compared against each <tt>clause</tt> in turn. If it doesn't
match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
unwinding continues further up the call stack.</p>
<p>The <tt>landingpad</tt> instruction has several restrictions:</p>