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PATCH: S/390: improve handling of structs returned by value
- From: Jim Blandy <jimb at zwingli dot cygnus dot com>
- To: gdb-patches at sources dot redhat dot com
- Date: Thu, 29 Nov 2001 17:26:47 -0500 (EST)
- Subject: PATCH: S/390: improve handling of structs returned by value
2001-11-29 Jim Blandy <jimb@redhat.com>
Tighten up GDB's support for returning structs by value.
* s390-tdep.c (s390_use_struct_convention): New function.
(s390_gdbarch_init): Register it as the S/390's
USE_STRUCT_CONVENTION method. Register
generic_cannot_extract_struct_value_address as our
EXTRACT_STRUCT_VALUE_ADDRESS method.
* arch-utils.c (generic_cannot_extract_struct_value_address): New
function.
* arch-utils.h: Add corresponding prototype.
* values.c (value_being_returned): Make error message a proper
sentence.
* s390-tdep.c (s390_frame_saved_pc_nofix): If the prologue didn't
save the return address register, assume that the return address
is still in there.
Index: gdb/s390-tdep.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/s390-tdep.c,v
retrieving revision 2.22
diff -c -r2.22 s390-tdep.c
*** gdb/s390-tdep.c 2001/11/29 05:04:17 2.22
--- gdb/s390-tdep.c 2001/11/29 22:16:23
***************
*** 1592,1597 ****
--- 1592,1608 ----
return sp;
}
+
+ static int
+ s390_use_struct_convention (int gcc_p, struct type *value_type)
+ {
+ enum type_code code = TYPE_CODE (value_type);
+
+ return (code == TYPE_CODE_STRUCT
+ || code == TYPE_CODE_UNION);
+ }
+
+
/* Return the GDB type object for the "standard" data type
of data in register N. */
struct type *
***************
*** 1735,1746 ****
set_gdbarch_cannot_fetch_register (gdbarch, s390_cannot_fetch_register);
set_gdbarch_cannot_store_register (gdbarch, s390_cannot_fetch_register);
set_gdbarch_get_saved_register (gdbarch, generic_get_saved_register);
! set_gdbarch_use_struct_convention (gdbarch, generic_use_struct_convention);
set_gdbarch_frame_chain_valid (gdbarch, func_frame_chain_valid);
set_gdbarch_register_name (gdbarch, s390_register_name);
set_gdbarch_stab_reg_to_regnum (gdbarch, s390_stab_reg_to_regnum);
set_gdbarch_dwarf_reg_to_regnum (gdbarch, s390_stab_reg_to_regnum);
set_gdbarch_dwarf2_reg_to_regnum (gdbarch, s390_stab_reg_to_regnum);
/* Parameters for inferior function calls. */
set_gdbarch_call_dummy_p (gdbarch, 1);
--- 1746,1759 ----
set_gdbarch_cannot_fetch_register (gdbarch, s390_cannot_fetch_register);
set_gdbarch_cannot_store_register (gdbarch, s390_cannot_fetch_register);
set_gdbarch_get_saved_register (gdbarch, generic_get_saved_register);
! set_gdbarch_use_struct_convention (gdbarch, s390_use_struct_convention);
set_gdbarch_frame_chain_valid (gdbarch, func_frame_chain_valid);
set_gdbarch_register_name (gdbarch, s390_register_name);
set_gdbarch_stab_reg_to_regnum (gdbarch, s390_stab_reg_to_regnum);
set_gdbarch_dwarf_reg_to_regnum (gdbarch, s390_stab_reg_to_regnum);
set_gdbarch_dwarf2_reg_to_regnum (gdbarch, s390_stab_reg_to_regnum);
+ set_gdbarch_extract_struct_value_address
+ (gdbarch, generic_cannot_extract_struct_value_address);
/* Parameters for inferior function calls. */
set_gdbarch_call_dummy_p (gdbarch, 1);
***************
*** 1756,1762 ****
set_gdbarch_call_dummy_breakpoint_offset_p (gdbarch, 1);
set_gdbarch_call_dummy_breakpoint_offset (gdbarch, 0);
set_gdbarch_call_dummy_stack_adjust_p (gdbarch, 0);
- set_gdbarch_extract_struct_value_address (gdbarch, 0);
set_gdbarch_fix_call_dummy (gdbarch, generic_fix_call_dummy);
set_gdbarch_push_return_address (gdbarch, s390_push_return_address);
set_gdbarch_sizeof_call_dummy_words (gdbarch,
--- 1769,1774 ----
Index: gdb/arch-utils.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/arch-utils.c,v
retrieving revision 2.27
diff -c -r2.27 arch-utils.c
*** gdb/arch-utils.c 2001/11/06 11:09:09 2.27
--- gdb/arch-utils.c 2001/11/29 22:16:25
***************
*** 240,245 ****
--- 240,260 ----
}
+ /* Under some ABI's that specify the `struct convention' for returning
+ structures by value, by the time we've returned from the function,
+ the return value is sitting there in the caller's buffer, but GDB
+ has no way to find the address of that buffer.
+
+ On such architectures, use this function as your
+ extract_struct_value_address method. When asked to a struct
+ returned by value in this fashion, GDB will print a nice error
+ message, instead of garbage. */
+ CORE_ADDR
+ generic_cannot_extract_struct_value_address (char *dummy)
+ {
+ return 0;
+ }
+
int
default_register_sim_regno (int num)
{
Index: gdb/arch-utils.h
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/arch-utils.h,v
retrieving revision 2.20
diff -c -r2.20 arch-utils.h
*** gdb/arch-utils.h 2001/11/06 11:09:09 2.20
--- gdb/arch-utils.h 2001/11/29 22:16:25
***************
*** 27,32 ****
--- 27,34 ----
/* Fallback for register convertible. */
extern gdbarch_register_convertible_ftype generic_register_convertible_not;
+ extern CORE_ADDR generic_cannot_extract_struct_value_address (char *dummy);
+
/* Helper function for targets that don't know how my arguments are
being passed */
extern gdbarch_frame_num_args_ftype frame_num_args_unknown;