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Re: [rfa/doc] correct info about best C++ compilers/debug formats
- From: David Carlton <carlton at math dot stanford dot edu>
- To: Michael Elizabeth Chastain <mec at shout dot net>
- Cc: drow at mvista dot com, eliz at gnu dot org, gdb-patches at sources dot redhat dot com
- Date: 03 Feb 2003 12:14:40 -0800
- Subject: Re: [rfa/doc] correct info about best C++ compilers/debug formats
- References: <200302032008.h13K8M230404@duracef.shout.net>
On Mon, 3 Feb 2003 14:08:22 -0600, Michael Elizabeth Chastain <mec@shout.net> said:
> Hi David,
>> Well, I wanted to include some sort of sentence that reassured users
>> that they probably didn't have to specify the debug format explicitly.
> How about:
> Most configurations of @value{NGCC} emit either DWARF2 or stabs+
> as their default debug format, so you usually don't need to specify a
> debug format explicitly.
I can go with that. I would assume that the + in 'stabs+' has to be
set off by @t, but TeXinfo doesn't complain; Eli, should I use stabs+
or stabs@t{+}?
Here's the next version of the patch; it changes this sentence, and
also replaces some uses of @samp{-gsomething} by @option{-gsomething},
which I assume is preferred.
David Carlton
carlton@math.stanford.edu
2003-02-03 David Carlton <carlton@math.stanford.edu>
* gdb.texinfo (C@t{++}): Recommend DWARF2, then stabs+.
(Variables): Recommend stabs+ and DWARF2.
(C plus plus expressions): Correct info about
compiler versions, debug formats.
PR symtab/874.
Index: gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.145
diff -u -p -r1.145 gdb.texinfo
--- gdb.texinfo 1 Feb 2003 20:51:06 -0000 1.145
+++ gdb.texinfo 3 Feb 2003 20:13:22 -0000
@@ -4711,13 +4711,13 @@ No symbol "foo" in current context.
To solve such problems, either recompile without optimizations, or use a
different debug info format, if the compiler supports several such
-formats. For example, @value{NGCC}, the @sc{gnu} C/C@t{++} compiler usually
-supports the @samp{-gstabs} option. @samp{-gstabs} produces debug info
-in a format that is superior to formats such as COFF. You may be able
-to use DWARF2 (@samp{-gdwarf-2}), which is also an effective form for
-debug info. See @ref{Debugging Options,,Options for Debugging Your
-Program or @sc{gnu} CC, gcc.info, Using @sc{gnu} CC}, for more
-information.
+formats. For example, @value{NGCC}, the @sc{gnu} C/C@t{++} compiler
+usually supports the @option{-gstabs+} option. @option{-gstabs+}
+produces debug info in a format that is superior to formats such as
+COFF. You may be able to use DWARF2 (@option{-gdwarf-2}), which is also
+an effective form for debug info. See @ref{Debugging Options,,Options
+for Debugging Your Program or @sc{gnu} CC, gcc.info, Using @sc{gnu} CC},
+for more information.
@node Arrays
@@ -7812,9 +7812,10 @@ effectively, you must compile your C@t{+
C@t{++} compiler, such as @sc{gnu} @code{g++}, or the HP ANSI C@t{++}
compiler (@code{aCC}).
-For best results when using @sc{gnu} C@t{++}, use the stabs debugging
-format. You can select that format explicitly with the @code{g++}
-command-line options @samp{-gstabs} or @samp{-gstabs+}. See
+For best results when using @sc{gnu} C@t{++}, use the DWARF2 debugging
+format; if it doesn't work on your system, try the stabs@t{+} debugging
+format. You can select those formats explicitly with the @code{g++}
+command-line options @option{-gdwarf-2} and @option{-gstabs+}. See
@ref{Debugging Options,,Options for Debugging Your Program or @sc{gnu}
CC, gcc.info, Using @sc{gnu} CC}, for more information.
@@ -8062,28 +8063,21 @@ and @samp{@{&"hi", &"there", &"fred"@}}
@cindex expressions in C@t{++}
@value{GDBN} expression handling can interpret most C@t{++} expressions.
-@cindex C@t{++} support, not in @sc{coff}
-@cindex @sc{coff} versus C@t{++}
-@cindex C@t{++} and object formats
-@cindex object formats and C@t{++}
-@cindex a.out and C@t{++}
-@cindex @sc{ecoff} and C@t{++}
-@cindex @sc{xcoff} and C@t{++}
-@cindex @sc{elf}/stabs and C@t{++}
-@cindex @sc{elf}/@sc{dwarf} and C@t{++}
-@c FIXME!! GDB may eventually be able to debug C++ using DWARF; check
-@c periodically whether this has happened...
+@cindex debugging C@t{++} programs
+@cindex C@t{++} compilers
+@cindex debug formats and C@t{++}
+@cindex @value{NGCC} and C@t{++}
@quotation
@emph{Warning:} @value{GDBN} can only debug C@t{++} code if you use the
-proper compiler. Typically, C@t{++} debugging depends on the use of
-additional debugging information in the symbol table, and thus requires
-special support. In particular, if your compiler generates a.out, MIPS
-@sc{ecoff}, RS/6000 @sc{xcoff}, or @sc{elf} with stabs extensions to the
-symbol table, these facilities are all available. (With @sc{gnu} CC,
-you can use the @samp{-gstabs} option to request stabs debugging
-extensions explicitly.) Where the object code format is standard
-@sc{coff} or @sc{dwarf} in @sc{elf}, on the other hand, most of the C@t{++}
-support in @value{GDBN} does @emph{not} work.
+proper compiler and the proper debug format. Currently, @value{GDBN}
+works best when debugging C@t{++} code that is compiled with
+@value{NGCC} 2.95.3 or with @value{NGCC} 3.1 or newer, using the options
+@option{-gdwarf-2} or @option{-gstabs+}. DWARF2 is preferred over
+stabs@t{+}. Most configurations of @value{NGCC} emit either DWARF2 or
+stabs@t{+} as their default debug format, so you usually don't need to
+specify a debug format explicitly. Other compilers and/or debug formats
+are likely to work badly or not at all when using @value{GDBN} to debug
+C@t{++} code.
@end quotation
@enumerate