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