+static int
+i386_darwin_arg_type_alignment (struct type *type)
+{
+ type = check_typedef (type);
+ /* According to Mac OS X ABI document (passing arguments):
+ 6. The caller places 64-bit vectors (__m64) on the parameter area,
+ aligned to 8-byte boundaries.
+ 7. [...] The caller aligns 128-bit vectors in the parameter area to
+ 16-byte boundaries. */
+ if (type->code () == TYPE_CODE_ARRAY && type->is_vector ())
+ return TYPE_LENGTH (type);
+ /* 4. The caller places all the fields of structures (or unions) with no
+ vector elements in the parameter area. These structures are 4-byte
+ aligned.
+ 5. The caller places structures with vector elements on the stack,
+ 16-byte aligned. */
+ if (type->code () == TYPE_CODE_STRUCT
+ || type->code () == TYPE_CODE_UNION)
+ {
+ int i;
+ int res = 4;
+ for (i = 0; i < type->num_fields (); i++)
+ {
+ int align
+ = i386_darwin_arg_type_alignment (type->field (i).type ());
+
+ res = std::max (res, align);
+ }
+ return res;
+ }
+ /* 2. The caller aligns nonvector arguments to 4-byte boundaries. */
+ return 4;
+}
+
+static CORE_ADDR
+i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
+ struct regcache *regcache, CORE_ADDR bp_addr,
+ int nargs, struct value **args, CORE_ADDR sp,
+ function_call_return_method return_method,
+ CORE_ADDR struct_addr)
+{
+ i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ gdb_byte buf[4];
+ int i;
+ int write_pass;
+
+ /* Determine the total space required for arguments and struct
+ return address in a first pass, then push arguments in a second pass. */
+
+ for (write_pass = 0; write_pass < 2; write_pass++)
+ {
+ int args_space = 0;
+ int num_m128 = 0;
+
+ if (return_method == return_method_struct)
+ {
+ if (write_pass)
+ {
+ /* Push value address. */
+ store_unsigned_integer (buf, 4, byte_order, struct_addr);
+ write_memory (sp, buf, 4);
+ }
+ args_space += 4;
+ }
+
+ for (i = 0; i < nargs; i++)
+ {
+ struct type *arg_type = value_enclosing_type (args[i]);
+
+ if (i386_m128_p (arg_type) && num_m128 < 4)
+ {
+ if (write_pass)
+ {
+ const gdb_byte *val = value_contents_all (args[i]).data ();
+ regcache->raw_write (I387_MM0_REGNUM(tdep) + num_m128, val);
+ }
+ num_m128++;
+ }
+ else
+ {
+ args_space = align_up (args_space,
+ i386_darwin_arg_type_alignment (arg_type));
+ if (write_pass)
+ write_memory (sp + args_space,
+ value_contents_all (args[i]).data (),
+ TYPE_LENGTH (arg_type));
+
+ /* The System V ABI says that:
+
+ "An argument's size is increased, if necessary, to make it a
+ multiple of [32-bit] words. This may require tail padding,
+ depending on the size of the argument."
+
+ This makes sure the stack stays word-aligned. */
+ args_space += align_up (TYPE_LENGTH (arg_type), 4);
+ }
+ }
+
+ /* Darwin i386 ABI:
+ 1. The caller ensures that the stack is 16-byte aligned at the point
+ of the function call. */
+ if (!write_pass)
+ sp = align_down (sp - args_space, 16);
+ }
+
+ /* Store return address. */
+ sp -= 4;
+ store_unsigned_integer (buf, 4, byte_order, bp_addr);
+ write_memory (sp, buf, 4);
+
+ /* Finally, update the stack pointer... */
+ store_unsigned_integer (buf, 4, byte_order, sp);
+ regcache->cooked_write (I386_ESP_REGNUM, buf);
+
+ /* ...and fake a frame pointer. */
+ regcache->cooked_write (I386_EBP_REGNUM, buf);
+
+ /* MarkK wrote: This "+ 8" is all over the place:
+ (i386_frame_this_id, i386_sigtramp_frame_this_id,
+ i386_dummy_id). It's there, since all frame unwinders for
+ a given target have to agree (within a certain margin) on the
+ definition of the stack address of a frame. Otherwise frame id
+ comparison might not work correctly. Since DWARF2/GCC uses the
+ stack address *before* the function call as a frame's CFA. On
+ the i386, when %ebp is used as a frame pointer, the offset
+ between the contents %ebp and the CFA as defined by GCC. */
+ return sp + 8;