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			197 lines
		
	
	
	
		
			9.3 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
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<!--
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This file documents the GNU linker LD
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(GNU Binutils)
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version 2.19.
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Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000,
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2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
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<div class="node">
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<p>
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<a name="Bug-Reporting"></a>Previous: <a rel="previous" accesskey="p" href="Bug-Criteria.html#Bug-Criteria">Bug Criteria</a>,
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Up: <a rel="up" accesskey="u" href="Reporting-Bugs.html#Reporting-Bugs">Reporting Bugs</a>
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<hr><br>
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</div>
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<h3 class="section">6.2 How to Report Bugs</h3>
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<p><a name="index-bug-reports-646"></a><a name="index-_0040command_007bld_007d-bugs_002c-reporting-647"></a>
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A number of companies and individuals offer support for <span class="sc">gnu</span>
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products.  If you obtained <span class="command">ld</span> from a support organization, we
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recommend you contact that organization first.
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   <p>You can find contact information for many support companies and
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individuals in the file <span class="file">etc/SERVICE</span> in the <span class="sc">gnu</span> Emacs
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distribution.
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   <p>Otherwise, send bug reports for <span class="command">ld</span> to
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<a href="http://www.sourceware.org/bugzilla/">http://www.sourceware.org/bugzilla/</a>.
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   <p>The fundamental principle of reporting bugs usefully is this:
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<strong>report all the facts</strong>.  If you are not sure whether to state a
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fact or leave it out, state it!
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   <p>Often people omit facts because they think they know what causes the
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problem and assume that some details do not matter.  Thus, you might
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assume that the name of a symbol you use in an example does not
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matter.  Well, probably it does not, but one cannot be sure.  Perhaps
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the bug is a stray memory reference which happens to fetch from the
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location where that name is stored in memory; perhaps, if the name
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were different, the contents of that location would fool the linker
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into doing the right thing despite the bug.  Play it safe and give a
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specific, complete example.  That is the easiest thing for you to do,
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and the most helpful.
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   <p>Keep in mind that the purpose of a bug report is to enable us to fix
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the bug if it is new to us.  Therefore, always write your bug reports
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on the assumption that the bug has not been reported previously.
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   <p>Sometimes people give a few sketchy facts and ask, “Does this ring a
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bell?”  This cannot help us fix a bug, so it is basically useless.  We
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respond by asking for enough details to enable us to investigate. 
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You might as well expedite matters by sending them to begin with.
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   <p>To enable us to fix the bug, you should include all these things:
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     <ul>
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<li>The version of <span class="command">ld</span>.  <span class="command">ld</span> announces it if you start it with
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the <span class="samp">--version</span> argument.
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     <p>Without this, we will not know whether there is any point in looking for
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the bug in the current version of <span class="command">ld</span>.
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     <li>Any patches you may have applied to the <span class="command">ld</span> source, including any
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patches made to the <code>BFD</code> library.
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     <li>The type of machine you are using, and the operating system name and
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version number.
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     <li>What compiler (and its version) was used to compile <span class="command">ld</span>—e.g. 
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“<code>gcc-2.7</code>”.
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     <li>The command arguments you gave the linker to link your example and
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observe the bug.  To guarantee you will not omit something important,
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list them all.  A copy of the Makefile (or the output from make) is
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sufficient.
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     <p>If we were to try to guess the arguments, we would probably guess wrong
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and then we might not encounter the bug.
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     <li>A complete input file, or set of input files, that will reproduce the
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bug.  It is generally most helpful to send the actual object files
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provided that they are reasonably small.  Say no more than 10K.  For
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bigger files you can either make them available by FTP or HTTP or else
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state that you are willing to send the object file(s) to whomever
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requests them.  (Note - your email will be going to a mailing list, so
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we do not want to clog it up with large attachments).  But small
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attachments are best.
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     <p>If the source files were assembled using <code>gas</code> or compiled using
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<code>gcc</code>, then it may be OK to send the source files rather than the
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object files.  In this case, be sure to say exactly what version of
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<code>gas</code> or <code>gcc</code> was used to produce the object files.  Also say
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how <code>gas</code> or <code>gcc</code> were configured.
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     <li>A description of what behavior you observe that you believe is
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incorrect.  For example, “It gets a fatal signal.”
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     <p>Of course, if the bug is that <span class="command">ld</span> gets a fatal signal, then we
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will certainly notice it.  But if the bug is incorrect output, we might
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not notice unless it is glaringly wrong.  You might as well not give us
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a chance to make a mistake.
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     <p>Even if the problem you experience is a fatal signal, you should still
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say so explicitly.  Suppose something strange is going on, such as, your
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copy of <span class="command">ld</span> is out of sync, or you have encountered a bug in the
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C library on your system.  (This has happened!)  Your copy might crash
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and ours would not.  If you told us to expect a crash, then when ours
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fails to crash, we would know that the bug was not happening for us.  If
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you had not told us to expect a crash, then we would not be able to draw
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any conclusion from our observations.
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     <li>If you wish to suggest changes to the <span class="command">ld</span> source, send us context
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diffs, as generated by <code>diff</code> with the <span class="samp">-u</span>, <span class="samp">-c</span>, or
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<span class="samp">-p</span> option.  Always send diffs from the old file to the new file. 
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If you even discuss something in the <span class="command">ld</span> source, refer to it by
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context, not by line number.
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     <p>The line numbers in our development sources will not match those in your
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sources.  Your line numbers would convey no useful information to us. 
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</ul>
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   <p>Here are some things that are not necessary:
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     <ul>
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<li>A description of the envelope of the bug.
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     <p>Often people who encounter a bug spend a lot of time investigating
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which changes to the input file will make the bug go away and which
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changes will not affect it.
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     <p>This is often time consuming and not very useful, because the way we
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will find the bug is by running a single example under the debugger
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with breakpoints, not by pure deduction from a series of examples. 
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We recommend that you save your time for something else.
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     <p>Of course, if you can find a simpler example to report <em>instead</em>
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of the original one, that is a convenience for us.  Errors in the
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output will be easier to spot, running under the debugger will take
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less time, and so on.
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     <p>However, simplification is not vital; if you do not want to do this,
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report the bug anyway and send us the entire test case you used.
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     <li>A patch for the bug.
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     <p>A patch for the bug does help us if it is a good one.  But do not omit
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the necessary information, such as the test case, on the assumption that
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a patch is all we need.  We might see problems with your patch and decide
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to fix the problem another way, or we might not understand it at all.
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     <p>Sometimes with a program as complicated as <span class="command">ld</span> it is very hard to
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construct an example that will make the program follow a certain path
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through the code.  If you do not send us the example, we will not be
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able to construct one, so we will not be able to verify that the bug is
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fixed.
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     <p>And if we cannot understand what bug you are trying to fix, or why your
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patch should be an improvement, we will not install it.  A test case will
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help us to understand.
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     <li>A guess about what the bug is or what it depends on.
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     <p>Such guesses are usually wrong.  Even we cannot guess right about such
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things without first using the debugger to find the facts. 
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</ul>
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