[Patch] Remove gccbug from bugreport.texi, take 4
Wolfgang Bangerth
bangerth@ices.utexas.edu
Thu May 15 05:22:00 GMT 2003
Appended are two patches to bugs.html and bugreport.texi/g77.texi. I think
I have taken care of all the suggestions that have been brought forward,
moving the pieces of information that weren't already duplicated in
bugs.html there. I have intentionally dropped a couple of things, in
particular the -g suggestion for assembler output and the debug_rtx
section. I think they're not really relevant in real life, and would only
make bugs.html longer than necessary.
So: Toon, can you ack the g77 part (which is the patch I sent you last
time + a few g77 specific additions to bugs.html), and Gerald/Joseph are
you happy with the rest? If so, I'll apply this to mainline and 3.3
(wwwdocs has no 3.3 branch, right?).
If this is in, I'll come back and do a little more clean-up in
bugreport.texi and g77.texi. I think, Joseph's right: most of that should
go, since it's in bugs.html and seems a little outdated in places. But let
me get the patch below in first.
W.
Index: htdocs/bugs.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/bugs.html,v
retrieving revision 1.67
diff -c -r1.67 bugs.html
*** htdocs/bugs.html 26 Mar 2003 21:19:41 -0000 1.67
--- htdocs/bugs.html 15 May 2003 00:30:18 -0000
***************
*** 48,55 ****
<h1><a name="report">Reporting Bugs</a></h1>
! <p>Our preferred way of receiving bugs is via the
! <a href="gnats.html">GCC GNATS bug reporting system</a>.</p>
<p>Before you report a bug, please check the
<a href="#known">list of well-known bugs</a> and, <strong>if possible
--- 48,58 ----
<h1><a name="report">Reporting Bugs</a></h1>
! <p>The main purpose of a bug report is to enable someone to fix the bug. The
! most important prerequisite for this is that the report must be complete and
! self-contained, which we explain in detail below.
! Our preferred way of receiving bugs is via our
! <a href="gnats.html">online bug reporting system</a>.</p>
<p>Before you report a bug, please check the
<a href="#known">list of well-known bugs</a> and, <strong>if possible
***************
*** 139,152 ****
<p>Please submit your bug report directly to the
<a href="gnats.html">GCC GNATS bug database</a>.
! Only if this is not possible, mail all information to
! <a href="mailto:bug-gcc@gnu.org">bug-gcc@gnu.org</a> or
! <a href="mailto:gcc-bugs@gcc.gnu.org">gcc-bugs@gcc.gnu.org</a>.</p>
!
! <p>The GCC lists have message size limits (200 kbytes) and bug reports
! over those limits will currently be bounced. If your bug is larger
! than that, please post it using the <a href="gnats.html">GCC GNATS bug
! database</a>.</p>
<h2><a name="detailed">Detailed bug reporting instructions</a></h2>
--- 142,153 ----
<p>Please submit your bug report directly to the
<a href="gnats.html">GCC GNATS bug database</a>.
! Alternatively, you can use the <code>gccbug</code> script that mails your bug
! report to the bug database.
! Only if all this is absolutely not possible, mail all information to
! <a href="mailto:gcc-bugs@gcc.gnu.org">gcc-bugs@gcc.gnu.org</a>, but note that
! such reports are often overlooked since they are not permanently recorded into
! the database for later processing.</p>
<h2><a name="detailed">Detailed bug reporting instructions</a></h2>
***************
*** 162,168 ****
source-file</i></code></blockquote>
<p>Typically the preprocessed file (extension <code>.i</code> for C or
! <code>.ii</code> for C++) will be large, so please compress the
resulting file with one of the popular compression programs such as
bzip2, gzip, zip or compress (in
decreasing order of preference). Use maximum compression
--- 163,170 ----
source-file</i></code></blockquote>
<p>Typically the preprocessed file (extension <code>.i</code> for C or
! <code>.ii</code> for C++, and <code>.f</code> if the preprocessor is used on
! Fortran files) will be large, so please compress the
resulting file with one of the popular compression programs such as
bzip2, gzip, zip or compress (in
decreasing order of preference). Use maximum compression
***************
*** 190,199 ****
subject indicating language and platform also helps.</p>
<p>Please avoid posting an archive (.tar, .shar or .zip); we generally
! need just a single file to reproduce the bug (the .i/.ii preprocessed
file), and, by storing it in an archive, you're just making our
volunteers' jobs harder. Only when your bug report requires multiple
! source files to be reproduced should you use an archive. In any case,
make sure the compiler version, error message, etc, are included in
the body of your bug report as plain text, even if needlessly
duplicated as part of an archive.</p>
--- 192,204 ----
subject indicating language and platform also helps.</p>
<p>Please avoid posting an archive (.tar, .shar or .zip); we generally
! need just a single file to reproduce the bug (the .i/.ii/.f preprocessed
file), and, by storing it in an archive, you're just making our
volunteers' jobs harder. Only when your bug report requires multiple
! source files to be reproduced should you use an archive. This is, for example,
! the case if you are using <code>INCLUDE</code> directives in Fortran code,
! which are not processed by the preprocessor, but the compiler. In that case,
! we need the main and all <code>INCLUDE</code>d files. In any case,
make sure the compiler version, error message, etc, are included in
the body of your bug report as plain text, even if needlessly
duplicated as part of an archive.</p>
Index: doc/bugreport.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/doc/bugreport.texi,v
retrieving revision 1.4
diff -c -r1.4 bugreport.texi
*** doc/bugreport.texi 11 Apr 2003 21:34:57 -0000 1.4
--- doc/bugreport.texi 15 May 2003 00:29:33 -0000
***************
*** 1,5 ****
@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
! @c 1999, 2000, 2001 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
--- 1,5 ----
@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
! @c 1999, 2000, 2001, 2003 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
***************
*** 29,42 ****
@menu
* Criteria: Bug Criteria. Have you really found a bug?
- * Where: Bug Lists. Where to send your bug report.
* Reporting: Bug Reporting. How to report a bug effectively.
- * GNATS: gccbug. You can use a bug reporting tool.
* Known: Trouble. Known problems.
* Help: Service. Where to ask for help.
@end menu
! @node Bug Criteria,Bug Lists,,Bugs
@section Have You Found a Bug?
@cindex bug criteria
--- 29,40 ----
@menu
* Criteria: Bug Criteria. Have you really found a bug?
* Reporting: Bug Reporting. How to report a bug effectively.
* Known: Trouble. Known problems.
* Help: Service. Where to ask for help.
@end menu
! @node Bug Criteria,Bug Reporting,,Bugs
@section Have You Found a Bug?
@cindex bug criteria
***************
*** 99,391 ****
suggestions for improvement of GCC are welcome in any case.
@end itemize
! @node Bug Lists,Bug Reporting,Bug Criteria,Bugs
! @section Where to Report Bugs
! @cindex bug report mailing lists
! @kindex gcc-bugs@@gcc.gnu.org or bug-gcc@@gnu.org
!
! Send bug reports for the GNU Compiler Collection to
! @email{gcc-bugs@@gcc.gnu.org}. In accordance with the GNU-wide
! convention, in which bug reports for tool ``foo'' are sent
! to @samp{bug-foo@@gnu.org}, the address @email{bug-gcc@@gnu.org}
! may also be used; it will forward to the address given above.
!
! Please read @uref{http://gcc.gnu.org/bugs.html} for additional and/or
! more up-to-date bug reporting instructions before you post a bug report.
!
! @node Bug Reporting,gccbug,Bug Lists,Bugs
! @section How to Report Bugs
@cindex compiler bugs, reporting
! The fundamental principle of reporting bugs usefully is this:
! @strong{report all the facts}. If you are not sure whether to state a
! fact or leave it out, state it!
!
! Often people omit facts because they think they know what causes the
! problem and they conclude that some details don't matter. Thus, you might
! assume that the name of the variable you use in an example does not matter.
! Well, probably it doesn't, 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 compiler 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.
!
! Keep in mind that the purpose of a bug report is to enable someone to
! fix the bug if it is not known. It isn't very important what happens if
! the bug is already known. Therefore, always write your bug reports on
! the assumption that the bug is not known.
!
! 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.
!
! Try to make your bug report self-contained. If we have to ask you for
! more information, it is best if you include all the previous information
! in your response, as well as the information that was missing.
!
! Please report each bug in a separate message. This makes it easier for
! us to track which bugs have been fixed and to forward your bugs reports
! to the appropriate maintainer.
!
! To enable someone to investigate the bug, you should include all these
! things:
!
! @itemize @bullet
! @item
! The version of GCC@. You can get this by running it with the
! @option{-v} option.
!
! Without this, we won't know whether there is any point in looking for
! the bug in the current version of GCC@.
!
! @item
! A complete input file that will reproduce the bug. If the bug is in the
! C preprocessor, send a source file and any header files that it
! requires. If the bug is in the compiler proper (@file{cc1}), send the
! preprocessor output generated by adding @option{-save-temps} to the
! compilation command (@pxref{Debugging Options}). When you do this, use
! the same @option{-I}, @option{-D} or @option{-U} options that you used in
! actual compilation. Then send the @var{input}.i or @var{input}.ii files
! generated.
!
! A single statement is not enough of an example. In order to compile it,
! it must be embedded in a complete file of compiler input; and the bug
! might depend on the details of how this is done.
!
! Without a real example one can compile, all anyone can do about your bug
! report is wish you luck. It would be futile to try to guess how to
! provoke the bug. For example, bugs in register allocation and reloading
! frequently depend on every little detail of the function they happen in.
!
! Even if the input file that fails comes from a GNU program, you should
! still send the complete test case. Don't ask the GCC maintainers to
! do the extra work of obtaining the program in question---they are all
! overworked as it is. Also, the problem may depend on what is in the
! header files on your system; it is unreliable for the GCC maintainers
! to try the problem with the header files available to them. By sending
! CPP output, you can eliminate this source of uncertainty and save us
! a certain percentage of wild goose chases.
!
! @item
! The command arguments you gave GCC to compile that example
! and observe the bug. For example, did you use @option{-O}? To guarantee
! you won't omit something important, list all the options.
!
! If we were to try to guess the arguments, we would probably guess wrong
! and then we would not encounter the bug.
!
! @item
! The type of machine you are using, and the operating system name and
! version number.
!
! @item
! The operands you gave to the @code{configure} command when you installed
! the compiler.
!
! @item
! A complete list of any modifications you have made to the compiler
! source. (We don't promise to investigate the bug unless it happens in
! an unmodified compiler. But if you've made modifications and don't tell
! us, then you are sending us on a wild goose chase.)
!
! Be precise about these changes. A description in English is not
! enough---send a context diff for them.
!
! Adding files of your own (such as a machine description for a machine we
! don't support) is a modification of the compiler source.
!
! @item
! Details of any other deviations from the standard procedure for installing
! GCC@.
!
! @item
! A description of what behavior you observe that you believe is
! incorrect. For example, ``The compiler gets a fatal signal,'' or,
! ``The assembler instruction at line 208 in the output is incorrect.''
!
! Of course, if the bug is that the compiler gets a fatal signal, then one
! can't miss it. But if the bug is incorrect output, the maintainer might
! not notice unless it is glaringly wrong. None of us has time to study
! all the assembler code from a 50-line C program just on the chance that
! one instruction might be wrong. We need @emph{you} to do this part!
!
! 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 the compiler is out of synch, or you have encountered a bug in
! the C library on your system. (This has happened!) Your copy might
! crash and the copy here would not. If you @i{said} to expect a crash,
! then when the compiler here fails to crash, we would know that the bug
! was not happening. If you don't say to expect a crash, then we would
! not know whether the bug was happening. We would not be able to draw
! any conclusion from our observations.
!
! If the problem is a diagnostic when compiling GCC with some other
! compiler, say whether it is a warning or an error.
!
! Often the observed symptom is incorrect output when your program is run.
! Sad to say, this is not enough information unless the program is short
! and simple. None of us has time to study a large program to figure out
! how it would work if compiled correctly, much less which line of it was
! compiled wrong. So you will have to do that. Tell us which source line
! it is, and what incorrect result happens when that line is executed. A
! person who understands the program can find this as easily as finding a
! bug in the program itself.
!
! @item
! If you send examples of assembler code output from GCC,
! please use @option{-g} when you make them. The debugging information
! includes source line numbers which are essential for correlating the
! output with the input.
!
! @item
! If you wish to mention something in the GCC source, refer to it by
! context, not by line number.
!
! The line numbers in the development sources don't match those in your
! sources. Your line numbers would convey no useful information to the
! maintainers.
!
! @item
! Additional information from a debugger might enable someone to find a
! problem on a machine which he does not have available. However, you
! need to think when you collect this information if you want it to have
! any chance of being useful.
!
! @cindex backtrace for bug reports
! For example, many people send just a backtrace, but that is never
! useful by itself. A simple backtrace with arguments conveys little
! about GCC because the compiler is largely data-driven; the same
! functions are called over and over for different RTL insns, doing
! different things depending on the details of the insn.
!
! Most of the arguments listed in the backtrace are useless because they
! are pointers to RTL list structure. The numeric values of the
! pointers, which the debugger prints in the backtrace, have no
! significance whatever; all that matters is the contents of the objects
! they point to (and most of the contents are other such pointers).
!
! In addition, most compiler passes consist of one or more loops that
! scan the RTL insn sequence. The most vital piece of information about
! such a loop---which insn it has reached---is usually in a local variable,
! not in an argument.
!
! @findex debug_rtx
! What you need to provide in addition to a backtrace are the values of
! the local variables for several stack frames up. When a local
! variable or an argument is an RTX, first print its value and then use
! the GDB command @code{pr} to print the RTL expression that it points
! to. (If GDB doesn't run on your machine, use your debugger to call
! the function @code{debug_rtx} with the RTX as an argument.) In
! general, whenever a variable is a pointer, its value is no use
! without the data it points to.
! @end itemize
!
! Here are some things that are not necessary:
!
! @itemize @bullet
! @item
! A description of the envelope of the bug.
!
! 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.
!
! 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. You might
! as well save your time for something else.
!
! Of course, if you can find a simpler example to report @emph{instead} of
! the original one, that is a convenience. Errors in the output will be
! easier to spot, running under the debugger will take less time, etc.
! Most GCC bugs involve just one function, so the most straightforward
! way to simplify an example is to delete all the function definitions
! except the one where the bug occurs. Those earlier in the file may be
! replaced by external declarations if the crucial function depends on
! them. (Exception: inline functions may affect compilation of functions
! defined later in the file.)
!
! However, simplification is not vital; if you don't want to do this,
! report the bug anyway and send the entire test case you used.
!
! @item
! In particular, some people insert conditionals @samp{#ifdef BUG} around
! a statement which, if removed, makes the bug not happen. These are just
! clutter; we won't pay any attention to them anyway. Besides, you should
! send us cpp output, and that can't have conditionals.
!
! @item
! A patch for the bug.
!
! A patch for the bug is useful if it is a good one. But don't 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.
!
! Sometimes with a program as complicated as GCC it is very hard to
! construct an example that will make the program follow a certain path
! through the code. If you don't send the example, we won't be able to
! construct one, so we won't be able to verify that the bug is fixed.
!
! And if we can't understand what bug you are trying to fix, or why your
! patch should be an improvement, we won't install it. A test case will
! help us to understand.
!
! See @uref{http://gcc.gnu.org/contribute.html}
! for guidelines on how to make it easy for us to
! understand and install your patches.
!
! @item
! A guess about what the bug is or what it depends on.
!
! Such guesses are usually wrong. Even I can't guess right about such
! things without first using the debugger to find the facts.
!
! @item
! A core dump file.
!
! We have no way of examining a core dump for your type of machine
! unless we have an identical system---and if we do have one,
! we should be able to reproduce the crash ourselves.
! @end itemize
!
! @node gccbug,, Bug Reporting, Bugs
! @section The gccbug script
! @cindex gccbug script
!
! To simplify creation of bug reports, and to allow better tracking of
! reports, we use the GNATS bug tracking system. Part of that system is
! the @command{gccbug} script. This is a Unix shell script, so you need a
! shell to run it. It is normally installed in the same directory where
! @command{gcc} is installed.
!
! The gccbug script is derived from send-pr, @pxref{using
! send-pr,,Creating new Problem Reports,send-pr,Reporting Problems}. When
! invoked, it starts a text editor so you can fill out the various fields
! of the report. When the you quit the editor, the report is automatically
! send to the bug reporting address.
!
! A number of fields in this bug report form are specific to GCC, and are
! explained at @uref{http://gcc.gnu.org/gnats.html}.
--- 97,108 ----
suggestions for improvement of GCC are welcome in any case.
@end itemize
! @node Bug Reporting,Trouble,Bug Criteria,Bugs
! @section How and where to Report Bugs
@cindex compiler bugs, reporting
! Bugs should be reported to our bug database. Please refer to
! @uref{http://gcc.gnu.org/bugs.html} for up-to-date instructions how to
! submit bug reports. Copies of this file in HTML (@file{bugs.html}) and
! plain text (@file{BUGS}) should also be part of the documentation that
! comes with GCC releases.
Index: f/g77.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/f/g77.texi,v
retrieving revision 1.102
diff -c -r1.102 g77.texi
*** f/g77.texi 11 May 2003 12:57:34 -0000 1.102
--- f/g77.texi 15 May 2003 00:29:35 -0000
***************
*** 2,9 ****
@c %**start of header
@setfilename g77.info
! @set last-update 2002-04-29
! @set copyrights-g77 1995,1996,1997,1998,1999,2000,2001,2002
@include root.texi
--- 2,9 ----
@c %**start of header
@setfilename g77.info
! @set last-update 2003-05-13
! @set copyrights-g77 1995,1996,1997,1998,1999,2000,2001,2002,2003
@include root.texi
***************
*** 10445,10451 ****
@menu
* Criteria: Bug Criteria. Have you really found a bug?
- * Where: Bug Lists. Where to send your bug report.
* Reporting: Bug Reporting. How to report a bug effectively.
@end menu
--- 10445,10450 ----
***************
*** 10636,10983 ****
exposes it more readily than other compilers.
@end itemize
- @node Bug Lists
- @section Where to Report Bugs
- @cindex bug report mailing lists
- @kindex @value{email-bugs}
- Send bug reports for GNU Fortran to @email{@value{email-bugs}}.
-
- Often people think of posting bug reports to a newsgroup instead of
- mailing them.
- This sometimes appears to work, but it has one problem which can be
- crucial: a newsgroup posting does not contain a mail path back to the
- sender.
- Thus, if maintainers need more information, they might be unable
- to reach you. For this reason, you should always send bug reports by
- mail to the proper mailing list.
-
- As a last resort, send bug reports on paper to:
-
- @example
- GNU Compiler Bugs
- Free Software Foundation
- 59 Temple Place - Suite 330
- Boston, MA 02111-1307, USA
- @end example
-
@node Bug Reporting
@section How to Report Bugs
@cindex compiler bugs, reporting
! The fundamental principle of reporting bugs usefully is this:
! @strong{report all the facts}.
! If you are not sure whether to state a
! fact or leave it out, state it!
!
! Often people omit facts because they think they know what causes the
! problem and they conclude that some details don't matter.
! Thus, you might
! assume that the name of the variable you use in an example does not matter.
! Well, probably it doesn't, 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 compiler 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.
!
! Keep in mind that the purpose of a bug report is to enable someone to
! fix the bug if it is not known.
! It isn't very important what happens if
! the bug is already known.
! Therefore, always write your bug reports on
! the assumption that the bug is not known.
!
! Sometimes people give a few sketchy facts and ask, ``Does this ring a
! bell?''
! This cannot help us fix a bug, so it is rarely helpful.
! We respond by asking for enough details to enable us to investigate.
! You might as well expedite matters by sending them to begin with.
! (Besides, there are enough bells ringing around here as it is.)
!
! Try to make your bug report self-contained.
! If we have to ask you for
! more information, it is best if you include all the previous information
! in your response, as well as the information that was missing.
!
! Please report each bug in a separate message.
! This makes it easier for
! us to track which bugs have been fixed and to forward your bugs reports
! to the appropriate maintainer.
!
! Do not compress and encode any part of your bug report using programs
! such as @file{uuencode}.
! If you do so it will slow down the processing
! of your bug.
! If you must submit multiple large files, use @file{shar},
! which allows us to read your message without having to run any
! decompression programs.
!
! (As a special exception for GNU Fortran bug-reporting, at least
! for now, if you are sending more than a few lines of code, if
! your program's source file format contains ``interesting'' things
! like trailing spaces or strange characters, or if you need to
! include binary data files, it is acceptable to put all the
! files together in a @command{tar} archive, and, whether you need to
! do that, it is acceptable to then compress the single file (@command{tar}
! archive or source file)
! using @command{gzip} and encode it via @command{uuencode}.
! Do not use any MIME stuff---the current maintainer can't decode this.
! Using @command{compress} instead of @command{gzip} is acceptable, assuming
! you have licensed the use of the patented algorithm in
! @command{compress} from Unisys.)
!
! To enable someone to investigate the bug, you should include all these
! things:
!
! @itemize @bullet
! @item
! The version of GNU Fortran.
! You can get this by running @command{g77} with the @option{-v} option.
! (Ignore any error messages that might be displayed
! when the linker is run.)
!
! Without this, we won't know whether there is any point in looking for
! the bug in the current version of GNU Fortran.
!
! @item
! @cindex preprocessor
! @cindex cpp program
! @cindex programs, cpp
! @pindex cpp
! A complete input file that will reproduce the bug.
!
! If your source file(s) require preprocessing
! (for example, their names have suffixes like
! @samp{.F}, @samp{.fpp}, @samp{.FPP}, and @samp{.r}),
! and the bug is in the compiler proper (@file{f771})
! or in a subsequent phase of processing,
! run your source file through the C preprocessor
! by doing @samp{g77 -E @var{sourcefile} > @var{newfile}}.
! Then, include the contents of @var{newfile} in the bug report.
! (When you do this, use the same preprocessor options---such as
! @option{-I}, @option{-D}, and @option{-U}---that you used in actual
! compilation.)
!
! A single statement is not enough of an example.
! In order to compile it,
! it must be embedded in a complete file of compiler input.
! The bug might depend on the details of how this is done.
!
! Without a real example one can compile,
! all anyone can do about your bug report is wish you luck.
! It would be futile to try to guess how to provoke the bug.
! For example, bugs in register allocation and reloading
! can depend on every little detail of the source and include files
! that trigger them.
!
! @item
! @cindex included files
! @cindex INCLUDE directive
! @cindex directive, INCLUDE
! @cindex #include directive
! @cindex directive, #include
! Note that you should include with your bug report any files
! included by the source file
! (via the @code{#include} or @code{INCLUDE} directive)
! that you send, and any files they include, and so on.
!
! It is not necessary to replace
! the @code{#include} and @code{INCLUDE} directives
! with the actual files in the version of the source file that
! you send, but it might make submitting the bug report easier
! in the end.
! However, be sure to @emph{reproduce} the bug using the @emph{exact}
! version of the source material you submit, to avoid wild-goose
! chases.
!
! @item
! The command arguments you gave GNU Fortran to compile that example
! and observe the bug. For example, did you use @option{-O}? To guarantee
! you won't omit something important, list all the options.
!
! If we were to try to guess the arguments, we would probably guess wrong
! and then we would not encounter the bug.
!
! @item
! The type of machine you are using, and the operating system name and
! version number.
! (Much of this information is printed by @samp{g77 -v}---if you
! include that, send along any additional info you have that you
! don't see clearly represented in that output.)
!
! @item
! The operands you gave to the @command{configure} command when you installed
! the compiler.
!
! @item
! A complete list of any modifications you have made to the compiler
! source. (We don't promise to investigate the bug unless it happens in
! an unmodified compiler. But if you've made modifications and don't tell
! us, then you are sending us on a wild-goose chase.)
!
! Be precise about these changes. A description in English is not
! enough---send a context diff for them.
!
! Adding files of your own (such as a machine description for a machine we
! don't support) is a modification of the compiler source.
!
! @item
! Details of any other deviations from the standard procedure for installing
! GNU Fortran.
!
! @item
! A description of what behavior you observe that you believe is
! incorrect. For example, ``The compiler gets a fatal signal,'' or,
! ``The assembler instruction at line 208 in the output is incorrect.''
!
! Of course, if the bug is that the compiler gets a fatal signal, then one
! can't miss it. But if the bug is incorrect output, the maintainer might
! not notice unless it is glaringly wrong. None of us has time to study
! all the assembler code from a 50-line Fortran program just on the chance that
! one instruction might be wrong. We need @emph{you} to do this part!
!
! 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 the compiler is out of synch, or you have encountered a bug in
! the C library on your system. (This has happened!) Your copy might
! crash and the copy here would not. If you @i{said} to expect a crash,
! then when the compiler here fails to crash, we would know that the bug
! was not happening. If you don't say to expect a crash, then we would
! not know whether the bug was happening. We would not be able to draw
! any conclusion from our observations.
!
! If the problem is a diagnostic when building GNU Fortran with some other
! compiler, say whether it is a warning or an error.
- Often the observed symptom is incorrect output when your program is run.
- Sad to say, this is not enough information unless the program is short
- and simple. None of us has time to study a large program to figure out
- how it would work if compiled correctly, much less which line of it was
- compiled wrong. So you will have to do that. Tell us which source line
- it is, and what incorrect result happens when that line is executed. A
- person who understands the program can find this as easily as finding a
- bug in the program itself.
-
- @item
- If you send examples of assembler code output from GNU Fortran,
- please use @option{-g} when you make them. The debugging information
- includes source line numbers which are essential for correlating the
- output with the input.
-
- @item
- If you wish to mention something in the GNU Fortran source, refer to it by
- context, not by line number.
-
- The line numbers in the development sources don't match those in your
- sources. Your line numbers would convey no convenient information to the
- maintainers.
-
- @item
- Additional information from a debugger might enable someone to find a
- problem on a machine which he does not have available. However, you
- need to think when you collect this information if you want it to have
- any chance of being useful.
-
- @cindex backtrace for bug reports
- For example, many people send just a backtrace, but that is never
- useful by itself. A simple backtrace with arguments conveys little
- about GNU Fortran because the compiler is largely data-driven; the same
- functions are called over and over for different RTL insns, doing
- different things depending on the details of the insn.
-
- Most of the arguments listed in the backtrace are useless because they
- are pointers to RTL list structure. The numeric values of the
- pointers, which the debugger prints in the backtrace, have no
- significance whatever; all that matters is the contents of the objects
- they point to (and most of the contents are other such pointers).
-
- In addition, most compiler passes consist of one or more loops that
- scan the RTL insn sequence. The most vital piece of information about
- such a loop---which insn it has reached---is usually in a local variable,
- not in an argument.
-
- @findex debug_rtx
- What you need to provide in addition to a backtrace are the values of
- the local variables for several stack frames up. When a local
- variable or an argument is an RTX, first print its value and then use
- the GDB command @command{pr} to print the RTL expression that it points
- to. (If GDB doesn't run on your machine, use your debugger to call
- the function @code{debug_rtx} with the RTX as an argument.) In
- general, whenever a variable is a pointer, its value is no use
- without the data it points to.
- @end itemize
-
- Here are some things that are not necessary:
-
- @itemize @bullet
- @item
- A description of the envelope of the bug.
-
- 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.
-
- 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. You might
- as well save your time for something else.
-
- Of course, if you can find a simpler example to report @emph{instead} of
- the original one, that is a convenience. Errors in the output will be
- easier to spot, running under the debugger will take less time, etc.
- Most GNU Fortran bugs involve just one function, so the most straightforward
- way to simplify an example is to delete all the function definitions
- except the one where the bug occurs. Those earlier in the file may be
- replaced by external declarations if the crucial function depends on
- them. (Exception: inline functions might affect compilation of functions
- defined later in the file.)
-
- However, simplification is not vital; if you don't want to do this,
- report the bug anyway and send the entire test case you used.
-
- @item
- In particular, some people insert conditionals @samp{#ifdef BUG} around
- a statement which, if removed, makes the bug not happen. These are just
- clutter; we won't pay any attention to them anyway. Besides, you should
- send us preprocessor output, and that can't have conditionals.
-
- @item
- A patch for the bug.
-
- A patch for the bug is useful if it is a good one. But don't 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.
-
- Sometimes with a program as complicated as GNU Fortran it is very hard to
- construct an example that will make the program follow a certain path
- through the code. If you don't send the example, we won't be able to
- construct one, so we won't be able to verify that the bug is fixed.
-
- And if we can't understand what bug you are trying to fix, or why your
- patch should be an improvement, we won't install it. A test case will
- help us to understand.
-
- See @uref{http://gcc.gnu.org/contribute.html}
- for guidelines on how to make it easy for us to
- understand and install your patches.
-
- @item
- A guess about what the bug is or what it depends on.
-
- Such guesses are usually wrong. Even the maintainer can't guess right
- about such things without first using the debugger to find the facts.
-
- @item
- A core dump file.
-
- We have no way of examining a core dump for your type of machine
- unless we have an identical system---and if we do have one,
- we should be able to reproduce the crash ourselves.
- @end itemize
@node Service
@chapter How To Get Help with GNU Fortran
--- 10635,10650 ----
exposes it more readily than other compilers.
@end itemize
@node Bug Reporting
@section How to Report Bugs
@cindex compiler bugs, reporting
! Bugs should be reported to our bug database. Please refer to
! @uref{http://gcc.gnu.org/bugs.html} for up-to-date instructions how to
! submit bug reports. Copies of this file in HTML (@file{bugs.html}) and
! plain text (@file{BUGS}) should also be part of the documentation that
! comes with GCC releases.
@node Service
@chapter How To Get Help with GNU Fortran
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