Refactoring of builtins and annotations in the back-end.

Before, the back-end languages had distinct instructions
- Iannot for annotations, taking structured expressions (annot_arg)
  as arguments, and producing no results'
- Ibuiltin for other builtins, using simple pseudoregs/locations/registers
  as arguments and results.

This branch enriches Ibuiltin instructions so that they take structured
expressions (builtin_arg and builtin_res) as arguments and results.
This way,
- Annotations fit the general pattern of builtin functions,
  so Iannot instructions are removed.
- EF_vload_global and EF_vstore_global become useless, as the
  same optimization can be achieved by EF_vload/vstore taking
  a structured argument of the "address of global" kind.
- Better code can be generated for builtin_memcpy between stack locations,
  or volatile accesses to stack locations.

Finally, this commit also introduces a new kind of external function,
EF_debug, which is like EF_annot but produces no observable events.
It will be used later to transport debug info through the back-end,
without preventing optimizations.

1 files changed, 1 insertions, 3 deletions

diff --git a/ia32/Asmgen.v b/ia32/Asmgen.v
index 2c1afc11..1ccde43b 100644
--- a/ia32/Asmgen.v
+++ b/ia32/Asmgen.v
@@ -536,9 +536,7 @@ Definition transl_instr (f: Mach.function) (i: Mach.instruction)
       OK (Pfreeframe f.(fn_stacksize) f.(fn_retaddr_ofs) f.(fn_link_ofs) :: 
           Pret :: k)
   | Mbuiltin ef args res =>
-      OK (Pbuiltin ef (List.map preg_of args) (List.map preg_of res) :: k)
-  | Mannot ef args =>
-      OK (Pannot ef (List.map (map_annot_arg preg_of) args) :: k)
+      OK (Pbuiltin ef (List.map (map_builtin_arg preg_of) args) (map_builtin_res preg_of res) :: k)
   end.
 
 (** Translation of a code sequence *)