My patch:
2007-05-24 Danny Smith <[EMAIL PROTECTED]>
PR target/27067
* doc/tm.texi (TARGET_MANGLE_DECL_ASSEMBLER_NAME): Document.
* targhooks.h (default_mangle_decl_assembler_name): Declare
default hook.
* targhooks.c (default_mangle_decl_assembler_name): Define
default hook.
* target-def.h (TARGET_MANGLE_DECL_ASSEMBLER_NAME) New. Set to
default hook.
* target.h (struct gcc_target): Add mangle_decl_assembler_name field.
* langhooks.c (lhd_set_decl_assembler_name): Call
targetm.mangle_decl_assembler_name for names with global scope.
breaks gdb usage for setting breakpoints on __stdcall functions in C
(but not C++)
The problem appear to derive from a difference between the DECL_NAME and
DECL_ASSEMBLER_NAME which was introduced by the patch. Windows targets
decorate stdcall assembler identifiers with an @n suffix. Before this
patch, the assembler decoration was only added to RTL names in
encode_section_info; after the patch the decoration is added upfront to
DECL_ASSEMBLER_NAME, because the extern assembler name is really the decorated
name.
Here is an example:
===================
/* foo.c */
int __stdcall bar()
{
return 1;
}
int main()
{
return bar();
}
===================
Compiling with
gcc -g -xc foo.c
then
C:\develop\bugs>gdb a
GNU gdb 6.5.50.20060706-cvs (cygwin-special) Copyright (C) 2006 Free
Software Foundation, Inc. GDB is free software, covered by the GNU
General Public License, and you ar welcome to change it and/or
distribute copies of it under certain condition Type "show copying" to
see the conditions. There is absolutely no warranty for GDB. Type "show
warranty" for details. This GDB was configured as "i686-pc-cygwin"...
(gdb) break bar
Function "bar" not defined.
However, there are no problems in C++ where there is also (and because
of name mangling, generally) a difference between the the DECL_NAME and
the DECL_ASSEMBLER_NAME.
compiling with
gcc -g -xc++ foo.c
then
C:\develop\bugs>gdb a
GNU gdb 6.5.50.20060706-cvs (cygwin-special)
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i686-pc-cygwin"...
(gdb) break bar
Breakpoint 1 at 0x4013a3: file foo.c, line 3.
Reverting this part of the patch
* langhooks.c (lhd_set_decl_assembler_name): Call
targetm.mangle_decl_assembler_name for names with global scope.
avoids the C debugging problem.
gdb knows how to handle C++ mangling diffs between DECL_NAME and
DECL_ASSEMBLER_NAME, so the C++ part of the patch:
* cp/mangle.c (mangle_decl): Call targetm.mangle_decl_assembler_name.
doesn't cause any problems.
Danny
--
Summary: _stdcall assembler names in win32 vs gdb
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dannysmith at users dot sourceforge dot net
GCC build triplet: i386-pc-mingw32
GCC host triplet: i386-pc-mingw32
GCC target triplet: i386-pc-mingw32
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33155
