RE: [CIL users] Problem with variable-length arrays

[Matt H. <ma...@cs...>]

> -----Original Message-----
> From: cil...@li... 
> [mailto:cil...@li...] On Behalf Of 
> Roberto Bagnara
> Sent: Wednesday, December 07, 2005 8:04 AM
> To: cil...@li...
> Subject: [CIL users] Problem with variable-length arrays
> 
> Maybe variable-length arrays are not supported by CIL;  I 
> assumed they were because the documentation says: "CIL 
> supports all GCC and MSVC extensions except for nested 
> functions and complex numbers."
> All the best,
> 
>     Roberto


Hi Roberto,

Variable-length arrays were supported as local variables, but not as
formals.  Here's a patch.  

Cabs2cil replaces the array type with a pointer type.  These are the right
semantics, although as Dillon noted last week we lose a little information
about the programmer's intention.

-- Matt



--- cil/src/frontc/cabs2cil.ml	4 Dec 2005 19:20:44 -0000	1.452
+++ cil/src/frontc/cabs2cil.ml	7 Dec 2005 23:56:32 -0000	1.453
@@ -2560,7 +2560,24 @@
         (* Make the argument as for a formal *)
         let doOneArg (s, (n, ndt, a, cloc)) : varinfo = 
           let s' = doSpecList n s in
-          makeVarInfoCabs ~isformal:true ~isglobal:false (convLoc cloc)
s' (n,ndt,a)
+          let ndt' =  match isVariableSizedArray ndt with
+              None -> ndt
+            | Some (ndt', se, len) -> 
+                (* If this is a variable-sized array, we replace the
array
+                   type with a pointer type.  This is the defined
behavior
+                   for array parameters, so we do not need to add this to
+                   varSizeArrays, fix sizeofs, etc. *)
+                if isNotEmpty se then
+                  E.s (error "array parameter: length not pure");
+                ndt'
+          in              
+          let vi = makeVarInfoCabs ~isformal:true ~isglobal:false 
+                     (convLoc cloc) s' (n,ndt',a) in
+          (* Add the formal to the environment, so it can be referenced
by
+             other formals  (e.g. in an array type, although that will be
+             changed to a pointer later, or though typeof).  *) 
+          addLocalToEnv vi.vname (EnvVar vi);
+          vi
         in
         let targs : varinfo list option = 
           match List.map doOneArg args'  with