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.

1 files changed, 15 insertions, 0 deletions

diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index 0dab00c..2b23951 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)
 {