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(*
*
* Copyright (c) 2001-2002,
* George C. Necula <necula@cs.berkeley.edu>
* Scott McPeak <smcpeak@cs.berkeley.edu>
* Wes Weimer <weimer@cs.berkeley.edu>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. The names of the contributors may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*)
(************************************************************************
* canonicalize performs several transformations to correct differences
* between C and C++, so that the output is (hopefully) valid C++ code.
* This is incomplete -- certain fixes which are necessary
* for some programs are not yet implemented.
*
* #1) C allows global variables to have multiple declarations and multiple
* (equivalent) definitions. This transformation removes all but one
* declaration and all but one definition.
*
* #2) Any variables that use C++ keywords as identifiers are renamed.
*
* #3) __inline is #defined to inline, and __restrict is #defined to nothing.
*
* #4) C allows function pointers with no specified arguments to be used on
* any argument list. To make C++ accept this code, we insert a cast
* from the function pointer to a type that matches the arguments. Of
* course, this does nothing to guarantee that the pointer actually has
* that type.
*
* #5) Makes casts from int to enum types explicit. (CIL changes enum
* constants to int constants, but doesn't use a cast.)
*
************************************************************************)
open Cil
module E = Errormsg
module H = Hashtbl
(* For transformation #1. Stores all variable definitions in the file. *)
let varDefinitions: (varinfo, global) H.t = H.create 111
class canonicalizeVisitor = object(self)
inherit nopCilVisitor
val mutable currentFunction: fundec = Cil.dummyFunDec;
(* A hashtable to prevent duplicate declarations. *)
val alreadyDeclared: (varinfo, unit) H.t = H.create 111
val alreadyDefined: (varinfo, unit) H.t = H.create 111
(* move variable declarations around *)
method vglob g = match g with
GVar(v, ({init = Some _} as inito), l) ->
(* A definition. May have been moved to an earlier position. *)
if H.mem alreadyDefined v then begin
ignore (E.warn "Duplicate definition of %s at %a.\n"
v.vname d_loc !currentLoc);
ChangeTo [] (* delete from here. *)
end else begin
H.add alreadyDefined v ();
if H.mem alreadyDeclared v then begin
(* Change the earlier declaration to Extern *)
let oldS = v.vstorage in
ignore (E.log "changing storage of %s from %a\n"
v.vname d_storage oldS);
v.vstorage <- Extern;
let newv = {v with vstorage = oldS} in
ChangeDoChildrenPost([GVar(newv, inito, l)], (fun g -> g) )
end else
DoChildren
end
| GVar(v, {init=None}, l)
| GVarDecl(v, l) when not (isFunctionType v.vtype) -> begin
(* A declaration. May have been moved to an earlier position. *)
if H.mem alreadyDefined v || H.mem alreadyDeclared v then
ChangeTo [] (* delete from here. *)
else begin
H.add alreadyDeclared v ();
DoChildren
end
end
| GFun(f, l) ->
currentFunction <- f;
DoChildren
| _ ->
DoChildren
(* #2. rename any identifiers whose names are C++ keywords *)
method vvdec v =
match v.vname with
| "bool"
| "catch"
| "cdecl"
| "class"
| "const_cast"
| "delete"
| "dynamic_cast"
| "explicit"
| "export"
| "false"
| "friend"
| "mutable"
| "namespace"
| "new"
| "operator"
| "pascal"
| "private"
| "protected"
| "public"
| "register"
| "reinterpret_cast"
| "static_cast"
| "template"
| "this"
| "throw"
| "true"
| "try"
| "typeid"
| "typename"
| "using"
| "virtual"
| "wchar_t"->
v.vname <- v.vname ^ "__cil2cpp";
DoChildren
| _ -> DoChildren
method vinst i =
(* #5. If an assignment or function call uses expressions as enum values,
add an explicit cast. *)
match i with
Set (dest, exp, l) -> begin
let typeOfDest = typeOfLval dest in
match unrollType typeOfDest with
TEnum _ -> (* add an explicit cast *)
let newI = Set(dest, mkCast exp typeOfDest, l) in
ChangeTo [newI]
| _ -> SkipChildren
end
| Call (dest, f, args, l) -> begin
let rt, formals, isva, attrs = splitFunctionType (typeOf f) in
if isva then
SkipChildren (* ignore vararg functions *)
else
match formals with
Some formals' -> begin
let newArgs = try
(*Iterate over the arguments, looking for formals that
expect enum types, and insert casts where necessary. *)
List.map2
(fun (actual: exp) (formalName, formalType, _) ->
match unrollType formalType with
TEnum _ -> mkCast actual formalType
| _ -> actual)
args
formals'
with Invalid_argument _ ->
E.s (error "Number of arguments to %a doesn't match type.\n"
d_exp f)
in
let newI = Call(dest, f, newArgs, l) in
ChangeTo [newI]
end
| None -> begin
(* #4. No arguments were specified for this type. To fix this, infer the
type from the arguments that are used n this instruction, and insert
a cast to that type.*)
match f with
Lval(Mem(fp), off) ->
let counter: int ref = ref 0 in
let newFormals = List.map
(fun (actual:exp) ->
incr counter;
let formalName = "a" ^ (string_of_int !counter) in
(formalName, typeOf actual, []))(* (name,type,attrs) *)
args in
let newFuncPtrType =
TPtr((TFun (rt, Some newFormals, false, attrs)), []) in
let newFuncPtr = Lval(Mem(mkCast fp newFuncPtrType), off) in
ChangeTo [Call(dest, newFuncPtr, args, l)]
| _ ->
ignore (warn "cppcanon: %a has no specified arguments, but it's not a function pointer." d_exp f);
SkipChildren
end
end
| _ -> SkipChildren
method vinit i =
(* #5. If an initializer uses expressions as enum values,
add an explicit cast. *)
match i with
SingleInit e -> DoChildren (* we don't handle simple initializers here,
because we don't know what type is expected.
This should be done in vglob if needed. *)
| CompoundInit(t, initList) ->
let changed: bool ref = ref false in
let initList' = List.map
(* iterate over the list, adding casts for any expression that
is expected to be an enum type. *)
(function
(Field(fi, off), SingleInit e) -> begin
match unrollType fi.ftype with
TEnum _ -> (* add an explicit cast *)
let newE = mkCast e fi.ftype in
changed := true;
(Field(fi, off), SingleInit newE)
| _ -> (* not enum, no cast needed *)
(Field(fi, off), SingleInit e)
end
| other ->
(* This is a more complicated initializer, and I don't think
it can have type enum. It's children might, though. *)
other)
initList in
if !changed then begin
(* There may be other casts needed in other parts of the
initialization, so do the children too. *)
ChangeDoChildrenPost(CompoundInit(t, initList'), (fun x -> x))
end else
DoChildren
(* #5. If a function returns an enum type, add an explicit cast to the
return type. *)
method vstmt stmt =
(match stmt.skind with
Return (Some exp, l) -> begin
let typeOfDest, _, _, _ =
splitFunctionType currentFunction.svar.vtype in
match unrollType typeOfDest with
TEnum _ ->
stmt.skind <- Return (Some (mkCast exp typeOfDest), l)
| _ -> ()
end
| _ -> ());
DoChildren
end (* class canonicalizeVisitor *)
(* Entry point for this extension *)
let canonicalize (f:file) =
visitCilFile (new canonicalizeVisitor) f;
(* #3. Finally, add some #defines to change C keywords to their C++
equivalents: *)
f.globals <-
GText( "#ifdef __cplusplus\n"
^" #define __restrict\n" (* "restrict" doesn't work *)
^" #define __inline inline\n"
^"#endif")
::f.globals
let feature : featureDescr =
{ fd_name = "canonicalize";
fd_enabled = ref false;
fd_description = "fixing some C-isms so that the result is C++ compliant.";
fd_extraopt = [];
fd_doit = canonicalize;
fd_post_check = true;
}
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