From a5bc362fca3d8a7c6d49b35dcf0b63440d23303c Mon Sep 17 00:00:00 2001
From: Alasdair Armstrong
Date: Tue, 26 Jun 2018 14:44:27 +0100
Subject: Add configuration registers so __SetConfig ASL can be translated

Registers can now be marked as configuration registers, for example:

register configuration CFG_RVBAR = 0x1300000

They work like ordinary registers except they can only be set by
functions with the 'configuration' effect and have no effect when
read. They also have an initialiser, like a let-binding. Internally
there is a new reg_dec constructor DEC_config. They are intended to
represent configuration parameters for the model, which can change
between runs, but don't change during execution. Currently they'll
only work when compiled to C. Internally registers can now have custom
effects for reads and writes rather than just rreg and wreg, so the
type signatures of Env.add_register and Env.get_register have changed,
as well as the Register lvar, so in the type checker we now write:

Env.add_register id read_effect write_effect typ
rather than
Env.add_register id typ

For the corresponding change to ASL parser there's a function
is_config in asl_to_sail.ml which controls what becomes a
configuration register for ARM. Some things we have to keep as
let-bindings because Sail can't handle them changing at runtime -
e.g. the length of vectors in other top-level definitions. Luckily
__SetConfig doesn't (yet) try to change those options.

Together these changes allow us to translate the ASL __SetConfig
function, which means we should get command-line option compatibility
with ArchEx for running the ARM conformance tests.
---
 src/parse_ast.ml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'src/parse_ast.ml')

diff --git a/src/parse_ast.ml b/src/parse_ast.ml
index 2848edc0..26cb9df7 100644
--- a/src/parse_ast.ml
+++ b/src/parse_ast.ml
@@ -98,7 +98,7 @@ base_effect_aux =  (* effect *)
  | BE_unspec (* unspecified values *)
  | BE_nondet (* nondeterminism from intra-instruction parallelism *)
  | BE_escape
-
+ | BE_config
 
 type 
 kid_aux =  (* identifiers with kind, ticked to differntiate from program variables *)
@@ -496,6 +496,7 @@ kind_def_aux =  (* Definition body for elements of kind; many are shorthands for
 type 
 dec_spec_aux =  (* Register declarations *)
    DEC_reg of atyp * id
+ | DEC_config of id * atyp * exp
  | DEC_alias of id * exp
  | DEC_typ_alias of atyp * id * exp
 
-- 
cgit v1.2.3