Mercurial > hg > CbC > CbC_gcc
diff gcc/doc/bugreport.texi @ 0:a06113de4d67
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author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
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date | Fri, 17 Jul 2009 14:47:48 +0900 |
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children | 04ced10e8804 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gcc/doc/bugreport.texi Fri Jul 17 14:47:48 2009 +0900 @@ -0,0 +1,91 @@ +@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +@c 1999, 2000, 2001, 2003, 2004, 2007 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Bugs +@chapter Reporting Bugs +@cindex bugs +@cindex reporting bugs + +Your bug reports play an essential role in making GCC reliable. + +When you encounter a problem, the first thing to do is to see if it is +already known. @xref{Trouble}. If it isn't known, then you should +report the problem. + +@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 + +If you are not sure whether you have found a bug, here are some guidelines: + +@itemize @bullet +@cindex fatal signal +@cindex core dump +@item +If the compiler gets a fatal signal, for any input whatever, that is a +compiler bug. Reliable compilers never crash. + +@cindex invalid assembly code +@cindex assembly code, invalid +@item +If the compiler produces invalid assembly code, for any input whatever +(except an @code{asm} statement), that is a compiler bug, unless the +compiler reports errors (not just warnings) which would ordinarily +prevent the assembler from being run. + +@cindex undefined behavior +@cindex undefined function value +@cindex increment operators +@item +If the compiler produces valid assembly code that does not correctly +execute the input source code, that is a compiler bug. + +However, you must double-check to make sure, because you may have a +program whose behavior is undefined, which happened by chance to give +the desired results with another C or C++ compiler. + +For example, in many nonoptimizing compilers, you can write @samp{x;} +at the end of a function instead of @samp{return x;}, with the same +results. But the value of the function is undefined if @code{return} +is omitted; it is not a bug when GCC produces different results. + +Problems often result from expressions with two increment operators, +as in @code{f (*p++, *p++)}. Your previous compiler might have +interpreted that expression the way you intended; GCC might +interpret it another way. Neither compiler is wrong. The bug is +in your code. + +After you have localized the error to a single source line, it should +be easy to check for these things. If your program is correct and +well defined, you have found a compiler bug. + +@item +If the compiler produces an error message for valid input, that is a +compiler bug. + +@cindex invalid input +@item +If the compiler does not produce an error message for invalid input, +that is a compiler bug. However, you should note that your idea of +``invalid input'' might be someone else's idea of ``an extension'' or +``support for traditional practice''. + +@item +If you are an experienced user of one of the languages GCC supports, your +suggestions for improvement of GCC are welcome in any case. +@end itemize + +@node Bug Reporting,,Bug Criteria,Bugs +@section How and where to Report Bugs +@cindex compiler bugs, reporting + +Bugs should be reported to the bug database at @value{BUGURL}.