Cleanups of syscall-related macros:

- Got rid of SET_THREAD_REG and some of the related macros, hallelujah.
  Replaced SET_SYSCALL_RETVAL with VGP_TRACK_SYSCALL_RETVAL, which avoids
  the redundant resetting of the syscall's return value.  The other
  remaining two related macros, SET_CLREQ_RETVAL and SET_CLCALL_RETVAL, were
  able to be moved to vg_scheduler.c rather than being global, hoorah.

- Passed the required syscall args to VG_(do_sys_sigaltstack)(), rather than
  grabbing them from within, removing its reliance on SYSCALL_ARG[12].
  It also makes the VG_(do_sys_sig*)() functions more consistent.

- As a result of these changes, was able to remove the SYSCALL_NUM,
  SYSCALL_RET and SYSCALL_ARG[123456] macros, yay.

- Replaced the implementations of VG_(set_return_from_syscall_shadow)() and
  VG_(get_exit_status_shadow)() with shorter ones that avoid using arch-state
  offsets.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@3630 a5019735-40e9-0310-863c-91ae7b9d1cf9
10 files changed