heptagon/minils/sequential/c.mli
2010-06-15 10:49:03 +02:00

131 lines
5.7 KiB
OCaml

(**************************************************************************)
(* *)
(* Heptagon *)
(* *)
(* Author : Marc Pouzet *)
(* Organization : Demons, LRI, University of Paris-Sud, Orsay *)
(* *)
(**************************************************************************)
(* $Id$ *)
(** Abstract syntax tree for C programs. *)
(** {2 C abstract syntax tree } *)
(** Here is the C abstract syntax tree used by MiniLS for its C backend. It does
not try to completly model the C language, only the relatively small part
that were are interested in (e.g. no function pointers or local variable
initialization). *)
(** C types relevant for Obc. Note the absence of function pointers. *)
type cty =
| Cty_int (** C machine-dependent integer type. *)
| Cty_float (** C machine-dependent single-precision floating-point type. *)
| Cty_char (** C character type. *)
| Cty_id of string (** Previously defined C type, such as an enum or struct. *)
| Cty_ptr of cty (** C points-to-other-type type. *)
| Cty_arr of int * cty (** A static array of the specified size. *)
| Cty_void (** Well, [void] is not really a C type. *)
(** A C block: declarations and statements. In source code form, it begins with
variable declarations before a list of semicolon-separated statements, the
whole thing being enclosed in curly braces. *)
type cblock = {
(** Variable declarations, where each declaration consists of a variable
name and the associated C type. *)
var_decls : (string * cty) list;
(** The actual statement forming our block. *)
block_body : cstm list;
}
(** C expressions. *)
and cexpr =
| Cuop of string * cexpr (** Unary operator with its name. *)
| Cbop of string * cexpr * cexpr (** Binary operator. *)
| Cfun_call of string * cexpr list (** Function call with its parameters. *)
| Cconst of cconst (** Constants. *)
| Clhs of clhs (** Left-hand-side expressions are obviously expressions! *)
| Caddrof of clhs (** Take the address of a left-hand-side expression. *)
| Cstructlit of string * cexpr list (** Structure literal " \{f1, f2, ... \}". *)
| Carraylit of cexpr list (** Array literal [e1, e2, ...]. *)
and cconst =
| Ccint of int (** Integer constant. *)
| Ccfloat of float (** Floating-point number constant. *)
| Ctag of string (** Tag, member of a previously declared enumeration. *)
| Cstrlit of string (** String literal, enclosed in double-quotes. *)
(** C left-hand-side (ie. affectable) expressions. *)
and clhs =
| Cvar of string (** A local variable. *)
| Cderef of clhs (** Pointer dereference, *ptr. *)
| Cfield of clhs * string (** Field access to left-hand-side. *)
| Carray of clhs * cexpr (** Array access clhs[cexpr] *)
(** C statements. *)
and cstm =
| Csexpr of cexpr (** Expression evaluation, may cause side-effects! *)
| Csblock of cblock (** A local sub-block, can have its own private decls. **)
| Cskip (** A dummy instruction that does nothing and will not be printed. *)
| Caffect of clhs * cexpr (** Affect the result of an expression to a lhs. *)
| Cif of cexpr * cstm list * cstm list (** Alternative *)
| Cswitch of cexpr * (string * cstm list) list (** Case/switch over an enum. *)
| Cwhile of cexpr * cstm list (** While loop. *)
| Cfor of string * int * int * cstm list (** For loop. int <= string < int *)
| Creturn of cexpr (** Ends a procedure/function by returning an expression.*)
(** C type declarations ; will {b always} correspond to a typedef in emitted
source code. *)
type cdecl =
(** C enum declaration, with associated value tags. *)
| Cdecl_enum of string * string list
(** C structure declaration, with each field's name and type. *)
| Cdecl_struct of string * (string * cty) list
(** C function declaration. *)
| Cdecl_function of string * cty * (string * cty) list
(** C function definition *)
type cfundef = {
f_name : string; (** The function's name. *)
f_retty : cty; (** The function's return type. *)
f_args : (string * cty) list; (** Each parameter's name and type. *)
f_body : cblock; (** Actual instructions, in the form of a block. *)
}
(** C top-level definitions. *)
type cdef =
| Cfundef of cfundef (** Function definition, see [cfundef]. *)
| Cvardef of string * cty (** A variable definition, with its name and type. *)
val cdecl_of_cfundef : cdef -> cdecl
(** A C file can be a source file, containing definitions, or a header file,
containing declarations. *)
type cfile_desc =
| Cheader of string list * cdecl list (** Header dependencies * declaration
list *)
| Csource of cdef list
type cfile = string * cfile_desc (** File name * file content *)
(** [output dir cprog] pretty-prints the C program [cprog] to new files in the
directory [dir]. *)
val output : string -> cfile list -> unit
(** [cname_of_name name] translates the string [name] to a valid C identifier.
Copied verbatim from the old C backend. *)
val cname_of_name : string -> string
(** Converts an expression to a lhs. *)
val lhs_of_exp : cexpr -> clhs
(** Returns the type of a pointer to a type, except for
types which are already pointers. *)
val pointer_to : cty -> cty
(** Returns whether a type is a pointer. *)
val is_pointer_type : cty -> bool
(** [array_base_ctype ty idx_list] returns the base type of an array
type. If idx_list = [i1; ..; ip] and a is a variable of type ty,
then it returns a[i1]..[ip]. *)
val array_base_ctype : cty -> int list -> cty