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From: Paul Smith <psmith@gnu.org>
To: gdb@sourceware.org
Subject: GDB syntax error if class members overlap C++ header file names
Date: Tue, 13 Feb 2018 15:37:00 -0000	[thread overview]
Message-ID: <1518536232.1130.9.camel@gnu.org> (raw)

Has anyone had any thoughts about
https://sourceware.org/bugzilla/show_bug.cgi?id=22231

This is a really unfortunate bug, because there are so many useful
symbol names which are also C++ header files!  Just ran into this again
with "queue".

Quoted from the bug:

> I've discovered that if you compile a C++ program with -ggdb3 (not
> -g) then any C++ header file (sans .h extension) that is included
> will cause a syntax error whenever you try to print that name.  Also,
> if you try to print a class member with that name it will also fail.
> 
> I've tried this with GDB 7.7, 7.11, and 8.0 and all behave the same
> way.  I've used both GCC 6.2 and 6.3.

And I've tried 8.1 as well just to be sure; same behavior:

> (gdb) p memory
> A syntax error in expression, near `'.
> 
> This will be the same for any other C++ (without .h) header that is
> included.  If you change to #include <memory.h> then you won't get
> this error (you'll get 'No symbole "memory" in current context.' as
> expected).
> 
> If you create a local variable or an auto variable named "memory",
> GDB will print it properly.
> 
> However, if you have a class member named "memory", GDB again won't
> parse it;

> (gdb) p foo.memory
> A syntax error in expression, near `'.
> 
> 
> 
> If you enable debugging you'll see:
> 
> (gdb) set debug parser on
> (gdb) p memory
> Starting parse
> Entering state 0
> Reading a token: Next token is token FILENAME (bval<0x1a66ac0>)
> Shifting token FILENAME (bval<0x1a66ac0>)
> Entering state 47
> Reducing stack by rule 107 (line 877):
>    $1 = token FILENAME (bval<0x1a66ac0>)
> -> $$ = nterm block ()
> Stack now 0
> Entering state 57
> Reading a token: Now at end of input.
> A syntax error in expression, near `'.


             reply	other threads:[~2018-02-13 15:37 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-13 15:37 Paul Smith [this message]
2018-02-13 15:52 ` Simon Marchi
2018-02-13 16:52   ` Paul Smith

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