diff options
| -rw-r--r-- | gdb/ChangeLog | 10 | ||||
| -rw-r--r-- | gdb/sh-tdep.c | 59 |
2 files changed, 51 insertions, 18 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 0f5deaf..99840d3 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,13 @@ +2003-10-09 Elena Zannoni <ezannoni@redhat.com> + + * sh-tdep.c (sh_gdbarch_init): Delete setting of push_dummy_code. + (sh_gdbarch_init): Delete function, it's only used for dummy calls + on stack. + + Based on input by Stephen Clarke (stephen.clarke@superh.com): + * sh-tdep.c (sh_use_struct_convention): Add comment explaining ABI + in detail. + 2003-10-09 Daniel Jacobowitz <drow@mvista.com> * remote-mips.c (mips_initialize): Remove unneeded call to diff --git a/gdb/sh-tdep.c b/gdb/sh-tdep.c index 9d50fbd..35b9e71 100644 --- a/gdb/sh-tdep.c +++ b/gdb/sh-tdep.c @@ -266,22 +266,6 @@ sh_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr) return breakpoint; } -static CORE_ADDR -sh_push_dummy_code (struct gdbarch *gdbarch, - CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc, - struct value **args, int nargs, - struct type *value_type, - CORE_ADDR *real_pc, CORE_ADDR *bp_addr) -{ - /* Allocate space sufficient for a breakpoint. */ - sp = (sp - 2) & ~1; - /* Store the address of that breakpoint */ - *bp_addr = sp; - /* sh always starts the call at the callee's entry point. */ - *real_pc = funaddr; - return sp; -} - /* Prologue looks like mov.l r14,@-r15 sts.l pr,@-r15 @@ -559,7 +543,47 @@ sh_skip_prologue (CORE_ADDR start_pc) return pc; } -/* Should call_function allocate stack space for a struct return? */ +/* Should call_function allocate stack space for a struct return? + + The ABI says: + + Aggregate types not bigger than 8 bytes that have the same size and + alignment as one of the integer scalar types are returned in the + same registers as the integer type they match. + + For example, a 2-byte aligned structure with size 2 bytes has the + same size and alignment as a short int, and will be returned in R0. + A 4-byte aligned structure with size 8 bytes has the same size and + alignment as a long long int, and will be returned in R0 and R1. + + When an aggregate type is returned in R0 and R1, R0 contains the + first four bytes of the aggregate, and R1 contains the + remainder. If the size of the aggregate type is not a multiple of 4 + bytes, the aggregate is tail-padded up to a multiple of 4 + bytes. The value of the padding is undefined. For little-endian + targets the padding will appear at the most significant end of the + last element, for big-endian targets the padding appears at the + least significant end of the last element. + + All other aggregate types are returned by address. The caller + function passes the address of an area large enough to hold the + aggregate value in R2. The called function stores the result in + this location." + + To reiterate, structs smaller than 8 bytes could also be returned + in memory, if they don't pass the "same size and alignment as an + integer type" rule. + + For example, in + + struct s { char c[3]; } wibble; + struct s foo(void) { return wibble; } + + the return value from foo() will be in memory, not + in R0, because there is no 3-byte integer type. + +*/ + static int sh_use_struct_convention (int gcc_p, struct type *type) { @@ -2032,7 +2056,6 @@ sh_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) set_gdbarch_decr_pc_after_break (gdbarch, 0); set_gdbarch_function_start_offset (gdbarch, 0); - set_gdbarch_push_dummy_code (gdbarch, sh_push_dummy_code); set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_nofpu); set_gdbarch_frame_args_skip (gdbarch, 0); |