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| Previous: <a rel="previous" accesskey="p" href="Bug-Criteria.html#Bug-Criteria">Bug Criteria</a>, |
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| <h3 class="section">6.2 How to Report Bugs</h3> |
| |
| <p><a name="index-bug-reports-693"></a><a name="index-g_t_0040command_007bld_007d-bugs_002c-reporting-694"></a> |
| A number of companies and individuals offer support for <span class="sc">gnu</span> |
| products. If you obtained <samp><span class="command">ld</span></samp> from a support organization, we |
| recommend you contact that organization first. |
| |
| <p>You can find contact information for many support companies and |
| individuals in the file <samp><span class="file">etc/SERVICE</span></samp> in the <span class="sc">gnu</span> Emacs |
| distribution. |
| |
| <p>Otherwise, send bug reports for <samp><span class="command">ld</span></samp> to |
| <a href="https://support.codesourcery.com/GNUToolchain/">https://support.codesourcery.com/GNUToolchain/</a>. |
| |
| <p>The fundamental principle of reporting bugs usefully is this: |
| <strong>report all the facts</strong>. If you are not sure whether to state a |
| fact or leave it out, state it! |
| |
| <p>Often people omit facts because they think they know what causes the |
| problem and assume that some details do not matter. Thus, you might |
| assume that the name of a symbol you use in an example does not |
| matter. Well, probably it does not, but one cannot be sure. Perhaps |
| the bug is a stray memory reference which happens to fetch from the |
| location where that name is stored in memory; perhaps, if the name |
| were different, the contents of that location would fool the linker |
| into doing the right thing despite the bug. Play it safe and give a |
| specific, complete example. That is the easiest thing for you to do, |
| and the most helpful. |
| |
| <p>Keep in mind that the purpose of a bug report is to enable us to fix |
| the bug if it is new to us. Therefore, always write your bug reports |
| on the assumption that the bug has not been reported previously. |
| |
| <p>Sometimes people give a few sketchy facts and ask, “Does this ring a |
| bell?” This cannot help us fix a bug, so it is basically useless. We |
| respond by asking for enough details to enable us to investigate. |
| You might as well expedite matters by sending them to begin with. |
| |
| <p>To enable us to fix the bug, you should include all these things: |
| |
| <ul> |
| <li>The version of <samp><span class="command">ld</span></samp>. <samp><span class="command">ld</span></samp> announces it if you start it with |
| the ‘<samp><span class="samp">--version</span></samp>’ argument. |
| |
| <p>Without this, we will not know whether there is any point in looking for |
| the bug in the current version of <samp><span class="command">ld</span></samp>. |
| |
| <li>Any patches you may have applied to the <samp><span class="command">ld</span></samp> source, including any |
| patches made to the <code>BFD</code> library. |
| |
| <li>The type of machine you are using, and the operating system name and |
| version number. |
| |
| <li>What compiler (and its version) was used to compile <samp><span class="command">ld</span></samp>—e.g. |
| “<code>gcc-2.7</code>”. |
| |
| <li>The command arguments you gave the linker to link your example and |
| observe the bug. To guarantee you will not omit something important, |
| list them all. A copy of the Makefile (or the output from make) is |
| sufficient. |
| |
| <p>If we were to try to guess the arguments, we would probably guess wrong |
| and then we might not encounter the bug. |
| |
| <li>A complete input file, or set of input files, that will reproduce the |
| bug. It is generally most helpful to send the actual object files |
| provided that they are reasonably small. Say no more than 10K. For |
| bigger files you can either make them available by FTP or HTTP or else |
| state that you are willing to send the object file(s) to whomever |
| requests them. (Note - your email will be going to a mailing list, so |
| we do not want to clog it up with large attachments). But small |
| attachments are best. |
| |
| <p>If the source files were assembled using <code>gas</code> or compiled using |
| <code>gcc</code>, then it may be OK to send the source files rather than the |
| object files. In this case, be sure to say exactly what version of |
| <code>gas</code> or <code>gcc</code> was used to produce the object files. Also say |
| how <code>gas</code> or <code>gcc</code> were configured. |
| |
| <li>A description of what behavior you observe that you believe is |
| incorrect. For example, “It gets a fatal signal.” |
| |
| <p>Of course, if the bug is that <samp><span class="command">ld</span></samp> gets a fatal signal, then we |
| will certainly notice it. But if the bug is incorrect output, we might |
| not notice unless it is glaringly wrong. You might as well not give us |
| a chance to make a mistake. |
| |
| <p>Even if the problem you experience is a fatal signal, you should still |
| say so explicitly. Suppose something strange is going on, such as, your |
| copy of <samp><span class="command">ld</span></samp> is out of sync, or you have encountered a bug in the |
| C library on your system. (This has happened!) Your copy might crash |
| and ours would not. If you told us to expect a crash, then when ours |
| fails to crash, we would know that the bug was not happening for us. If |
| you had not told us to expect a crash, then we would not be able to draw |
| any conclusion from our observations. |
| |
| <li>If you wish to suggest changes to the <samp><span class="command">ld</span></samp> source, send us context |
| diffs, as generated by <code>diff</code> with the ‘<samp><span class="samp">-u</span></samp>’, ‘<samp><span class="samp">-c</span></samp>’, or |
| ‘<samp><span class="samp">-p</span></samp>’ option. Always send diffs from the old file to the new file. |
| If you even discuss something in the <samp><span class="command">ld</span></samp> source, refer to it by |
| context, not by line number. |
| |
| <p>The line numbers in our development sources will not match those in your |
| sources. Your line numbers would convey no useful information to us. |
| </ul> |
| |
| <p>Here are some things that are not necessary: |
| |
| <ul> |
| <li>A description of the envelope of the bug. |
| |
| <p>Often people who encounter a bug spend a lot of time investigating |
| which changes to the input file will make the bug go away and which |
| changes will not affect it. |
| |
| <p>This is often time consuming and not very useful, because the way we |
| will find the bug is by running a single example under the debugger |
| with breakpoints, not by pure deduction from a series of examples. |
| We recommend that you save your time for something else. |
| |
| <p>Of course, if you can find a simpler example to report <em>instead</em> |
| of the original one, that is a convenience for us. Errors in the |
| output will be easier to spot, running under the debugger will take |
| less time, and so on. |
| |
| <p>However, simplification is not vital; if you do not want to do this, |
| report the bug anyway and send us the entire test case you used. |
| |
| <li>A patch for the bug. |
| |
| <p>A patch for the bug does help us if it is a good one. But do not omit |
| the necessary information, such as the test case, on the assumption that |
| a patch is all we need. We might see problems with your patch and decide |
| to fix the problem another way, or we might not understand it at all. |
| |
| <p>Sometimes with a program as complicated as <samp><span class="command">ld</span></samp> it is very hard to |
| construct an example that will make the program follow a certain path |
| through the code. If you do not send us the example, we will not be |
| able to construct one, so we will not be able to verify that the bug is |
| fixed. |
| |
| <p>And if we cannot understand what bug you are trying to fix, or why your |
| patch should be an improvement, we will not install it. A test case will |
| help us to understand. |
| |
| <li>A guess about what the bug is or what it depends on. |
| |
| <p>Such guesses are usually wrong. Even we cannot guess right about such |
| things without first using the debugger to find the facts. |
| </ul> |
| |
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| |
