From c8f9d51ce2e3eb695d8539d5615d0831ff906b3b Mon Sep 17 00:00:00 2001 From: Jim Blandy Date: Thu, 29 Nov 2001 22:24:42 +0000 Subject: [PATCH] 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. --- gdb/ChangeLog | 10 ++++++++++ gdb/arch-utils.c | 15 +++++++++++++++ gdb/arch-utils.h | 2 ++ gdb/s390-tdep.c | 16 ++++++++++++++-- 4 files changed, 41 insertions(+), 2 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index df9242f17d4..823cee6bebf 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,15 @@ 2001-11-29 Jim Blandy + 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. diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c index 0dab00c9330..2b23951fb9b 100644 --- a/gdb/arch-utils.c +++ b/gdb/arch-utils.c @@ -240,6 +240,21 @@ generic_register_convertible_not (int num) } +/* 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) { diff --git a/gdb/arch-utils.h b/gdb/arch-utils.h index 5dec3c2bb78..b065decb270 100644 --- a/gdb/arch-utils.h +++ b/gdb/arch-utils.h @@ -27,6 +27,8 @@ extern int gdbarch_debug; /* 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; diff --git a/gdb/s390-tdep.c b/gdb/s390-tdep.c index 465780f04f3..4ec129c9ccc 100644 --- a/gdb/s390-tdep.c +++ b/gdb/s390-tdep.c @@ -1592,6 +1592,17 @@ s390_push_arguments (int nargs, struct value **args, CORE_ADDR sp, 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 * @@ -1735,12 +1746,14 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) 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_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); @@ -1756,7 +1769,6 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) 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, -- 2.30.2