add set cp-abi command

Jim Ingham
2002-03-13T18:56:33Z

Hi, all...

gdb assumes that it will never see a mix of gcc2 & gcc3 compiled C++
code in a single executable. So it determines which abi to use by
setting it to gnu-v2, and then if it EVER sees a v3 style mangled name,
it switches it to v3. This breaks down in the case where you have some
shared libraries compiled with gcc3, but the user code is compiled with
gcc2. This is a perfectly okay thing to do if the libraries don't
export any C++ symbols, but gdb will get the abi wrong, and you won't be
able to print any C++ objects in the user code. Ouch!

I am not currently proposing any fancy mechanism to try to switch on the
fly between the two. The problem is temporary so I don't really think
it is worth the effort to cook up such a scheme. Rather, I just added a
"set cp-abi" command so that my users can fix the problem by hand when
they notice it arising.

Here is the patch:

2002-03-12 James Ingham <jingham@apple.com>

* cp-abi.c (set_cp_abi_cmd, show_cp_abi_cmd,
show_cp_abis_cmd): New functions, allow you to set & show
cplus abi's in case gdb gets it wrong.
(_initialize_cp_abi): Define the cp-abi switching commands.

Index: cp-abi.c
===================================================================
RCS file: /cvs/src/src/gdb/cp-abi.c,v
retrieving revision 1.3
diff -c -w -r1.3 cp-abi.c
*** cp-abi.c 2002/01/04 18:20:19 1.3
--- cp-abi.c 2002/03/13 18:46:57
***************
*** 21,26 ****
--- 21,29 ----
#include "defs.h"
#include "value.h"
#include "cp-abi.h"
+ #include "command.h"
+ #include "ui-out.h"
+ #include "gdbcmd.h"

struct cp_abi_ops current_cp_abi;

***************
*** 103,109 ****
--- 106,164 ----
int i;
for (i = 0; i < num_cp_abis; i++)
if (strcmp (cp_abis[i].shortname, short_name) == 0)
+ {
current_cp_abi = cp_abis[i];
return 1;
+ }
+
+ return 0;
+ }
+
+ void
+ set_cp_abi_cmd (char *args, int from_tty)
+ {
+
+ if (!switch_to_cp_abi (args))
+ error ("Could not find ABI: \"%s\" in ABI list\n", args);
+ }
+
+ void
+ show_cp_abi_cmd (char *args, int from_tty)
+ {
+ ui_out_text (uiout, "The current cplus abi is: ");
+
+ ui_out_field_string (uiout, "cp-abi", current_cp_abi.shortname);
+ ui_out_text (uiout, ".\n");
+ }
+
+ void
+ show_cp_abis_cmd (char *args, int from_tty)
+ {
+ int i;
+ ui_out_text (uiout, "The valid cplus abi's are:\n");
+
+ ui_out_tuple_begin (uiout, "cp-abi-list");
+ for (i = 0; i < num_cp_abis; i++)
+ {
+ ui_out_field_string (uiout, "cp-abi", cp_abis[i].shortname);
+ ui_out_text (uiout, "\n");
+ }
+ ui_out_tuple_end (uiout);
+
+ }
+
+ void
+ _initialize_cp_abi (void)
+ {
+ struct cmd_list_element *cmd;
+
+ cmd = add_cmd ("cp-abi", class_obscure , set_cp_abi_cmd,
+ "Set the ABI used for inspecting C++ objects",
&setlist);
+
+ cmd = add_cmd ("cp-abi", class_obscure, show_cp_abi_cmd,
+ "Show the ABI used for inspecting C++ objects",
&showlist);
+ cmd = add_cmd ("cp-abis", class_obscure, show_cp_abis_cmd,
+ "List the available ABIs for inspecting C++ objects",
&showlist);
+
}

Jim
--
Jim Ingham jingham@apple.com
Developer Tools - gdb
Apple Computer