mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-23 03:02:36 +01:00
New document
llvm-svn: 6275
This commit is contained in:
Chris Lattner
parent
558335f4fd
commit
609f9dea47
197
docs/HowToSubmitABug.html
Normal file
197
docs/HowToSubmitABug.html
Normal file
@ -0,0 +1,197 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
||||
<html><head><title>How to submit an LLVM bug report</title></head>
|
||||
|
||||
<body bgcolor=white>
|
||||
|
||||
<table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
|
||||
<tr><td> <font size=+3 color="#EEEEFF" face="Georgia,Palatino,Times,Roman"><b>How to submit an LLVM bug report</b></font></td>
|
||||
</tr></table>
|
||||
|
||||
<table border=0 width=100%>
|
||||
<tr><td valign=top>
|
||||
<p><font size=+1>
|
||||
<ol>
|
||||
<li><a href="#introduction">Introduction - Got bugs?</a>
|
||||
<li><a href="#crashers">Crashing Bugs</a>
|
||||
<ul>
|
||||
<li><a href="#front-end">Front-end bugs</a>
|
||||
<li><a href="#gccas">GCCAS bugs</a>
|
||||
<li><a href="#gccld">GCCLD bugs</a>
|
||||
<li><a href="#passes">Bugs in LLVM passes</a>
|
||||
</ul>
|
||||
<li><a href="#miscompilations">Miscompilations</a>
|
||||
|
||||
<p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></b><p>
|
||||
</ol><p></font>
|
||||
</td><td valign=top align=right>
|
||||
<img src="Debugging.gif" width=444 height=314>
|
||||
</td></tr>
|
||||
</table>
|
||||
|
||||
|
||||
<!-- *********************************************************************** -->
|
||||
<table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
|
||||
<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
|
||||
<a name="introduction">Introduction - Got bugs?
|
||||
</b></font></td></tr></table><ul>
|
||||
<!-- *********************************************************************** -->
|
||||
|
||||
If you're working with LLVM and run into a bug, we definitely want to know about
|
||||
it. This document describes what you can do to increase the odds of getting it
|
||||
fixed quickly.<p>
|
||||
|
||||
Basically you have to do two things at a minimum. First, decide whether the bug
|
||||
<a href="#crashers">crashes the compiler</a> (or an LLVM pass), or if the
|
||||
compiler is <a href="#miscompilations">miscompiling</a> the program. Based on
|
||||
what type of bug it is, follow the instructions in the linked section to narrow
|
||||
down the bug so that the person who fixes it will be able to find the problem
|
||||
more easily.<p>
|
||||
|
||||
Once you have a reduced test-case, email information about the bug to: <a
|
||||
href="mailto:llvmbugs@cs.uiuc.edu">llvmbugs@cs.uiuc.edu</a>. This should
|
||||
include all of the information necessary to reproduce the problem, including
|
||||
where you got the LLVM tree from (if you're not working out of CVS).<p>
|
||||
|
||||
Thanks for helping us make LLVM better!<p>
|
||||
|
||||
|
||||
<!-- *********************************************************************** -->
|
||||
</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
|
||||
<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
|
||||
<a name="crashers">Crashing Bugs
|
||||
</b></font></td></tr></table><ul>
|
||||
<!-- *********************************************************************** -->
|
||||
|
||||
More often than not, bugs in the compiler cause it to crash - often due to an
|
||||
assertion failure of some sort. If you are running <tt><b>opt</b></tt> or
|
||||
<tt><b>analyze</b></tt> directly, and something crashes, jump to the section on
|
||||
<a href="#passes">bugs in LLVM passes</a>. Otherwise, the most important
|
||||
piece of the puzzle is to figure out if it is the GCC-based front-end that is
|
||||
buggy or if it's one of the LLVM tools that has problems.<p>
|
||||
|
||||
To figure out which program is crashing (the front-end, <tt><b>gccas</b></tt>,
|
||||
or <tt><b>gccld</b></tt>), run the <tt><b>llvm-gcc</b></tt> command line as you
|
||||
were when the crash occurred, but add a <tt>-v</tt> option to the command line.
|
||||
The compiler will print out a bunch of stuff, and should end with telling you
|
||||
that one of <tt><b>cc1</b></tt>, <tt><b>gccas</b></tt>, or <tt><b>gccld</b></tt>
|
||||
crashed.<p>
|
||||
|
||||
<ul>
|
||||
<li>If <tt><b>cc1</b></tt> crashed, you found a problem with the front-end.
|
||||
Jump ahead to the section on <a href="#front-end">front-end bugs</a>.
|
||||
<li>If <tt><b>gccas</b></tt> crashed, you found a bug in <a href="#gccas">one of
|
||||
the passes in <tt><b>gccas</b></tt></a>.
|
||||
<li>If <tt><b>gccld</b></tt> crashed, you found a bug in <a href="#gccld">one
|
||||
of the passes in <tt><b>gccld</b></tt></a>.
|
||||
<li>Otherwise, something really weird happened. Email the list with what you
|
||||
have at this point.
|
||||
</ul><p>
|
||||
|
||||
|
||||
<!-- ======================================================================= -->
|
||||
</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
|
||||
<tr><td> </td><td width="100%">
|
||||
<font color="#EEEEFF" face="Georgia,Palatino"><b>
|
||||
<a name="front-end">Front-end bugs
|
||||
</b></font></td></tr></table><ul>
|
||||
|
||||
If the problem is in the front-end, pretty much the only thing you can do is
|
||||
preprocess the input (compile with the <tt>-E</tt> option) and send us the
|
||||
results. There is no good way to reduce source-level test-cases that I know
|
||||
of... if you do know, send me information and we can extend this section. :)<p>
|
||||
|
||||
|
||||
<!-- ======================================================================= -->
|
||||
</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
|
||||
<tr><td> </td><td width="100%">
|
||||
<font color="#EEEEFF" face="Georgia,Palatino"><b>
|
||||
<a name="gccas">GCCAS bugs
|
||||
</b></font></td></tr></table><ul>
|
||||
|
||||
If you find that a bug crashes in the <tt><b>gccas</b></tt> stage of
|
||||
compilation, compile your test-case to a <tt>.s</tt> file with the <tt>-S</tt>
|
||||
option to <tt><b>llvm-gcc</b></tt>. Then run:<p>
|
||||
|
||||
<pre>
|
||||
<b>gccas</b> -debug-pass=Arguments < /dev/null -o - > /dev/null
|
||||
</pre><p>
|
||||
|
||||
... which will print a list of arguments, indicating the list of passes that
|
||||
<tt><b>gccas</b></tt> runs. Once you have the input file and the list of
|
||||
passes, go to the section on <a href="#passes">debugging bugs in LLVM
|
||||
passes</a>.<p>
|
||||
|
||||
|
||||
<!-- ======================================================================= -->
|
||||
</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
|
||||
<tr><td> </td><td width="100%">
|
||||
<font color="#EEEEFF" face="Georgia,Palatino"><b>
|
||||
<a name="gccld">GCCLD bugs
|
||||
</b></font></td></tr></table><ul>
|
||||
|
||||
If you find that a bug crashes in the <tt><b>gccld</b></tt> stage of
|
||||
compilation, gather all of the <tt>.o</tt> bytecode files and libraries that are
|
||||
being linked together (the "<tt><b>llvm-gcc</b> -v</tt>" output should include
|
||||
the full list of objects linked). Then run:<p>
|
||||
|
||||
<pre>
|
||||
<b>gccld</b> -debug-pass=Arguments < /dev/null -o - > /dev/null
|
||||
</pre><p>
|
||||
|
||||
... which will print a list of arguments, indicating the list of passes that
|
||||
<tt><b>gccld</b></tt> runs. Once you have the input files and the list of
|
||||
passes, go to the section on <a href="#passes">debugging bugs in LLVM
|
||||
passes</a>.<p>
|
||||
|
||||
<!-- ======================================================================= -->
|
||||
</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
|
||||
<tr><td> </td><td width="100%">
|
||||
<font color="#EEEEFF" face="Georgia,Palatino"><b>
|
||||
<a name="passes">Bugs in LLVM passes
|
||||
</b></font></td></tr></table><ul>
|
||||
|
||||
At this point, you should have some number of LLVM assembly files or bytecode
|
||||
files and a list of passes which crash when run on the specified input. In
|
||||
order to reduce the list of passes (which is probably large) and the input to
|
||||
something tractable, use the <tt><b>bugpoint</b></tt> tool as follows:<p>
|
||||
|
||||
<pre>
|
||||
<b>bugpoint</b> <input files> <list of passes>
|
||||
</pre><p>
|
||||
|
||||
<tt><b>bugpoint</b></tt> will print a bunch of output as it reduces the
|
||||
test-case, but it should eventually print something like this:<p>
|
||||
|
||||
<pre>
|
||||
...
|
||||
Emitted bytecode to 'bugpoint-reduced-simplified.bc'
|
||||
|
||||
*** You can reproduce the problem with: opt bugpoint-reduced-simplified.bc -licm
|
||||
</pre><p>
|
||||
|
||||
Once you complete this, please send the LLVM bytecode file and the command line
|
||||
to reproduce the problem to the llvmbugs mailing list.<p>
|
||||
|
||||
|
||||
<!-- *********************************************************************** -->
|
||||
</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
|
||||
<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
|
||||
<a name="miscompilations">Miscompilations
|
||||
</b></font></td></tr></table><ul>
|
||||
<!-- *********************************************************************** -->
|
||||
|
||||
Fortunately we haven't had to many miscompilations. Because of this, this
|
||||
section is a TODO. Basically, use bugpoint to track down the problem.<p>
|
||||
|
||||
|
||||
<!-- *********************************************************************** -->
|
||||
</ul>
|
||||
<!-- *********************************************************************** -->
|
||||
|
||||
<hr><font size-1>
|
||||
<address><a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
|
||||
<!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
|
||||
<!-- hhmts start -->
|
||||
Last modified: Wed May 21 17:20:13 CDT 2003
|
||||
<!-- hhmts end -->
|
||||
</font></body></html>
|
||||
Loading…
Reference in New Issue
Block a user