gcc/c-aux-info.c

   1 /* Generate information regarding function declarations and definitions based
   2    on information stored in GCC's tree structure.  This code implements the
   3    -aux-info option.
   4
   5    This code was written by Ron Guilmette (rfg@mcc.com).
   6
   7    Copyright (C) 1989, 1991 Free Software Foundation, Inc.
   8
   9 This file is part of GNU CC.
  10
  11 GNU CC is free software; you can redistribute it and/or modify
  12 it under the terms of the GNU General Public License as published by
  13 the Free Software Foundation; either version 2, or (at your option)
  14 any later version.
  15
  16 GNU CC is distributed in the hope that it will be useful,
  17 but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 GNU General Public License for more details.
  20
  21 You should have received a copy of the GNU General Public License
  22 along with GNU CC; see the file COPYING.  If not, write to
  23 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  24
  25 #include <stdio.h>
  26 #include "config.h"
  27 #include "flags.h"
  28 #include "tree.h"
  29 #include "c-tree.h"
  30
  31 extern char* xmalloc ();
  32
  33 enum formals_style_enum {
  34   ansi,
  35   k_and_r_names,
  36   k_and_r_decls
  37 };
  38 typedef enum formals_style_enum formals_style;
  39
  40
  41 static char* data_type;
  42
  43 static char * concat ();
  44 static char * concat3 ();
  45 static char * gen_formal_list_for_type ();
  46 static int    deserves_ellipsis ();
  47 static char * gen_formal_list_for_func_def ();
  48 static char * gen_type ();
  49 static char * gen_decl ();
  50 void   gen_aux_info_record ();
  51 \f
  52 /*  Take two strings and mash them together into a newly allocated area.  */
  53
  54 static char*
  55 concat (s1, s2)
  56      char* s1;
  57      char* s2;
  58 {
  59   int size1, size2;
  60   char* ret_val;
  61
  62   if (!s1)
  63     s1 = "";
  64   if (!s2)
  65     s2 = "";
  66
  67   size1 = strlen (s1);
  68   size2 = strlen (s2);
  69   ret_val = xmalloc (size1 + size2 + 1);
  70   strcpy (ret_val, s1);
  71   strcpy (&ret_val[size1], s2);
  72   return ret_val;
  73 }
  74
  75 /*  Take three strings and mash them together into a newly allocated area.  */
  76
  77 static char*
  78 concat3 (s1, s2, s3)
  79      char* s1;
  80      char* s2;
  81      char* s3;
  82 {
  83   int size1, size2, size3;
  84   char* ret_val;
  85
  86   if (!s1)
  87     s1 = "";
  88   if (!s2)
  89     s2 = "";
  90   if (!s3)
  91     s3 = "";
  92
  93   size1 = strlen (s1);
  94   size2 = strlen (s2);
  95   size3 = strlen (s3);
  96   ret_val = xmalloc (size1 + size2 + size3 + 1);
  97   strcpy (ret_val, s1);
  98   strcpy (&ret_val[size1], s2);
  99   strcpy (&ret_val[size1+size2], s3);
 100   return ret_val;
 101 }
 102
 103 /* Given a string representing an entire type or an entire declaration
 104    which only lacks the actual "data-type" specifier (at its left end),
 105    affix the data-type specifier to the left end of the given type
 106    specification or object declaration.
 107
 108    Because of C language weirdness, the data-type specifier (which normally
 109    goes in at the very left end) may have to be slipped in just to the
 110    right of any leading "const" or "volatile" qualifiers (there may be more
 111    than one).  Actually this may not be strictly necessary because it seems
 112    that GCC (at least) accepts `<data-type> const foo;' and treats it the
 113    same as `const <data-type> foo;' but people are accustomed to seeing
 114    `const char *foo;' and *not* `char const *foo;' so we try to create types
 115    that look as expected.  */
 116
 117 static char*
 118 affix_data_type (type_or_decl)
 119      char *type_or_decl;
 120 {
 121   char *p = type_or_decl;
 122   char *qualifiers_then_data_type;
 123   char saved;
 124
 125   /* Skip as many leading const's or volatile's as there are.  */
 126
 127   for (;;)
 128     {
 129       if (!strncmp (p, "volatile", 8))
 130         {
 131           p += 9;
 132           continue;
 133         }
 134       if (!strncmp (p, "const", 5))
 135         {
 136           p += 6;
 137           continue;
 138         }
 139       break;
 140     }
 141
 142   /* p now points to the place where we can insert the data type.  We have to
 143      add a blank after the data-type of course.  */
 144
 145   if (p == type_or_decl)
 146     return concat3 (data_type, " ", type_or_decl);
 147
 148   saved = *p;
 149   *p = '\0';
 150   qualifiers_then_data_type = concat (type_or_decl, data_type);
 151   *p = saved;
 152   return concat3 (qualifiers_then_data_type, " ", p);
 153 }
 154
 155 /* Given a tree node which represents some "function type", generate the
 156    source code version of a formal parameter list (of some given style) for
 157    this function type.  Return the whole formal parameter list (including
 158    a pair of surrounding parens) as a string.   Note that if the style
 159    we are currently aiming for is non-ansi, then we just return a pair
 160    of empty parens here. */
 161
 162 static char*
 163 gen_formal_list_for_type (fntype, style)
 164      tree fntype;
 165      formals_style style;
 166 {
 167   char* formal_list = "";
 168   tree formal_type;
 169
 170   if (style != ansi)
 171     return "()";
 172
 173   formal_type = TYPE_ARG_TYPES (fntype);
 174   while (formal_type && TREE_VALUE (formal_type) != void_type_node)
 175     {
 176       char* this_type;
 177
 178       if (*formal_list)
 179         formal_list = concat (formal_list, ", ");
 180
 181       this_type = gen_type ("", TREE_VALUE (formal_type), ansi);
 182       formal_list =
 183           (strlen (this_type))
 184               ? concat (formal_list, affix_data_type (this_type))
 185               : concat (formal_list, data_type);
 186
 187       formal_type = TREE_CHAIN (formal_type);
 188     }
 189
 190   /* If we got to here, then we are trying to generate an ANSI style formal
 191      parameters list.
 192
 193      New style prototyped ANSI formal parameter lists should in theory always
 194      contain some stuff between the opening and closing parens, even if it is
 195      only "void".
 196
 197      The brutal truth though is that there is lots of old K&R code out there
 198      which contains declarations of "pointer-to-function" parameters and
 199      these almost never have fully specified formal parameter lists associated
 200      with them.  That is, the pointer-to-function parameters are declared
 201      with just empty parameter lists.
 202
 203      In cases such as these, protoize should really insert *something* into
 204      the vacant parameter lists, but what?  It has no basis on which to insert
 205      anything in particular.
 206
 207      Here, we make life easy for protoize by trying to distinguish between
 208      K&R empty parameter lists and new-style prototyped parameter lists
 209      that actually contain "void".  In the latter case we (obviously) want
 210      to output the "void" verbatim, and that what we do.  In the former case,
 211      we do our best to give protoize something nice to insert.
 212
 213      This "something nice" should be something that is still legal (when
 214      re-compiled) but something that can clearly indicate to the user that
 215      more typing information (for the parameter list) should be added (by
 216      hand) at some convenient moment.
 217
 218      The string chosen here is a comment with question marks in it.  */
 219
 220   if (!*formal_list)
 221     {
 222       if (TYPE_ARG_TYPES (fntype))
 223         /* assert (TREE_VALUE (TYPE_ARG_TYPES (fntype)) == void_type_node);  */
 224         formal_list = "void";
 225       else
 226         formal_list = "/* ??? */";
 227     }
 228   else
 229     {
 230       /* If there were at least some parameters, and if the formals-types-list
 231          petered out to a NULL (i.e. without being terminated by a
 232          void_type_node) then we need to tack on an ellipsis.  */
 233       if (!formal_type)
 234         formal_list = concat (formal_list, ", ...");
 235     }
 236
 237   return concat3 (" (", formal_list, ")");
 238 }
 239
 240 /* For the generation of an ANSI prototype for a function definition, we have
 241    to look at the formal parameter list of the function's own "type" to
 242    determine if the function's formal parameter list should end with an
 243    ellipsis.  Given a tree node, the following function will return non-zero
 244    if the "function type" parameter list should end with an ellipsis.  */
 245
 246 static int
 247 deserves_ellipsis (fntype)
 248      tree fntype;
 249 {
 250   tree formal_type;
 251
 252   formal_type = TYPE_ARG_TYPES (fntype);
 253   while (formal_type && TREE_VALUE (formal_type) != void_type_node)
 254     formal_type = TREE_CHAIN (formal_type);
 255
 256   /* If there were at least some parameters, and if the formals-types-list
 257      petered out to a NULL (i.e. without being terminated by a void_type_node)
 258      then we need to tack on an ellipsis.  */
 259
 260   return (!formal_type && TYPE_ARG_TYPES (fntype));
 261 }
 262
 263 /* Generate a parameter list for a function definition (in some given style).
 264
 265    Note that this routine has to be separate (and different) from the code that
 266    generates the prototype parameter lists for function declarations, because
 267    in the case of a function declaration, all we have to go on is a tree node
 268    representing the function's own "function type".  This can tell us the types
 269    of all of the formal parameters for the function, but it cannot tell us the
 270    actual *names* of each of the formal parameters.  We need to output those
 271    parameter names for each function definition.
 272
 273    This routine gets a pointer to a tree node which represents the actual
 274    declaration of the given function, and this DECL node has a list of formal
 275    parameter (variable) declarations attached to it.  These formal parameter
 276    (variable) declaration nodes give us the actual names of the formal
 277    parameters for the given function definition.
 278
 279    This routine returns a string which is the source form for the entire
 280    function formal parameter list.  */
 281
 282 static char*
 283 gen_formal_list_for_func_def (fndecl, style)
 284      tree fndecl;
 285      formals_style style;
 286 {
 287   char* formal_list = "";
 288   tree formal_decl;
 289
 290   formal_decl = DECL_ARGUMENTS (fndecl);
 291   while (formal_decl)
 292     {
 293       char *this_formal;
 294
 295       if (*formal_list && ((style == ansi) || (style == k_and_r_names)))
 296         formal_list = concat (formal_list, ", ");
 297       this_formal = gen_decl (formal_decl, 0, style);
 298       if (style == k_and_r_decls)
 299         formal_list = concat3 (formal_list, this_formal, "; ");
 300       else
 301         formal_list = concat (formal_list, this_formal);
 302       formal_decl = TREE_CHAIN (formal_decl);
 303     }
 304   if (style == ansi)
 305     {
 306       if (!DECL_ARGUMENTS (fndecl))
 307         formal_list = concat (formal_list, "void");
 308       if (deserves_ellipsis (TREE_TYPE (fndecl)))
 309         formal_list = concat (formal_list, ", ...");
 310     }
 311   if ((style == ansi) || (style == k_and_r_names))
 312     formal_list = concat3 (" (", formal_list, ")");
 313   return formal_list;
 314 }
 315
 316 /* Generate a string which is the source code form for a given type (t).  This
 317    routine is ugly and complex because the C syntax for declarations is ugly
 318    and complex.  This routine is straightforward so long as *no* pointer types,
 319    array types, or function types are involved.
 320
 321    In the simple cases, this routine will return the (string) value which was
 322    passed in as the "ret_val" argument.  Usually, this starts out either as an
 323    empty string, or as the name of the declared item (i.e. the formal function
 324    parameter variable).
 325
 326    This routine will also return with the global variable "data_type" set to
 327    some string value which is the "basic" data-type of the given complete type.
 328    This "data_type" string can be concatenated onto the front of the returned
 329    string after this routine returns to its caller.
 330
 331    In complicated cases involving pointer types, array types, or function
 332    types, the C declaration syntax requires an "inside out" approach, i.e. if
 333    you have a type which is a "pointer-to-function" type, you need to handle
 334    the "pointer" part first, but it also has to be "innermost" (relative to
 335    the declaration stuff for the "function" type).  Thus, is this case, you
 336    must prepend a "(*" and append a ")" to the name of the item (i.e. formal
 337    variable).  Then you must append and prepend the other info for the
 338    "function type" part of the overall type.
 339
 340    To handle the "innermost precedence" rules of complicated C declarators, we
 341    do the following (in this routine).  The input parameter called "ret_val"
 342    is treated as a "seed".  Each time gen_type is called (perhaps recursively)
 343    some additional strings may be appended or prepended (or both) to the "seed"
 344    string.  If yet another (lower) level of the GCC tree exists for the given
 345    type (as in the case of a pointer type, an array type, or a function type)
 346    then the (wrapped) seed is passed to a (recursive) invocation of gen_type()
 347    this recursive invocation may again "wrap" the (new) seed with yet more
 348    declarator stuff, by appending, prepending (or both).  By the time the
 349    recursion bottoms out, the "seed value" at that point will have a value
 350    which is (almost) the complete source version of the declarator (except
 351    for the data_type info).  Thus, this deepest "seed" value is simply passed
 352    back up through all of the recursive calls until it is given (as the return
 353    value) to the initial caller of the gen_type() routine.  All that remains
 354    to do at this point is for the initial caller to prepend the "data_type"
 355    string onto the returned "seed".  */
 356
 357 static char*
 358 gen_type (ret_val, t, style)
 359      char* ret_val;
 360      tree t;
 361      formals_style style;
 362 {
 363   tree chain_p;
 364
 365   if (TYPE_NAME (t) && DECL_NAME (TYPE_NAME (t)))
 366     data_type = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (t)));
 367   else
 368     {
 369       switch (TREE_CODE (t))
 370         {
 371         case POINTER_TYPE:
 372           if (TYPE_READONLY (t))
 373             ret_val = concat ("const ", ret_val);
 374           if (TYPE_VOLATILE (t))
 375             ret_val = concat ("volatile ", ret_val);
 376
 377           ret_val = concat ("*", ret_val);
 378
 379           if (TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE || TREE_CODE (TREE_TYPE (t)) == FUNCTION_TYPE)
 380             ret_val = concat3 ("(", ret_val, ")");
 381
 382           ret_val = gen_type (ret_val, TREE_TYPE (t), style);
 383
 384           return ret_val;
 385
 386         case ARRAY_TYPE:
 387           ret_val = gen_type (concat (ret_val, "[]"), TREE_TYPE (t), style);
 388           break;
 389
 390         case FUNCTION_TYPE:
 391           ret_val = gen_type (concat (ret_val, gen_formal_list_for_type (t, style)), TREE_TYPE (t), style);
 392           break;
 393
 394         case IDENTIFIER_NODE:
 395           data_type = IDENTIFIER_POINTER (t);
 396           break;
 397
 398         /* The following three cases are complicated by the fact that a
 399            user may do something really stupid, like creating a brand new
 400            "anonymous" type specification in a formal argument list (or as
 401            part of a function return type specification).  For example:
 402
 403                 int f (enum { red, green, blue } color);
 404
 405            In such cases, we have no name that we can put into the prototype
 406            to represent the (anonymous) type.  Thus, we have to generate the
 407            whole darn type specification.  Yuck!  */
 408
 409         case RECORD_TYPE:
 410           if (TYPE_NAME (t))
 411             data_type = IDENTIFIER_POINTER (TYPE_NAME (t));
 412           else
 413             {
 414               data_type = "";
 415               chain_p = TYPE_FIELDS (t);
 416               while (chain_p)
 417                 {
 418                   data_type = concat (data_type, gen_decl (chain_p, 0, ansi));
 419                   chain_p = TREE_CHAIN (chain_p);
 420                   data_type = concat (data_type, "; ");
 421                 }
 422               data_type = concat3 ("{ ", data_type, "}");
 423             }
 424           data_type = concat ("struct ", data_type);
 425           break;
 426
 427         case UNION_TYPE:
 428           if (TYPE_NAME (t))
 429             data_type = IDENTIFIER_POINTER (TYPE_NAME (t));
 430           else
 431             {
 432               data_type = "";
 433               chain_p = TYPE_FIELDS (t);
 434               while (chain_p)
 435                 {
 436                   data_type = concat (data_type, gen_decl (chain_p, 0, ansi));
 437                   chain_p = TREE_CHAIN (chain_p);
 438                   data_type = concat (data_type, "; ");
 439                 }
 440               data_type = concat3 ("{ ", data_type, "}");
 441             }
 442           data_type = concat ("union ", data_type);
 443           break;
 444
 445         case ENUMERAL_TYPE:
 446           if (TYPE_NAME (t))
 447             data_type = IDENTIFIER_POINTER (TYPE_NAME (t));
 448           else
 449             {
 450               data_type = "";
 451               chain_p = TYPE_VALUES (t);
 452               while (chain_p)
 453                 {
 454                   data_type = concat (data_type,
 455                         IDENTIFIER_POINTER (TREE_PURPOSE (chain_p)));
 456                   chain_p = TREE_CHAIN (chain_p);
 457                   if (chain_p)
 458                     data_type = concat (data_type, ", ");
 459                 }
 460               data_type = concat3 ("{ ", data_type, " }");
 461             }
 462           data_type = concat ("enum ", data_type);
 463           break;
 464
 465         case TYPE_DECL:
 466           data_type = IDENTIFIER_POINTER (DECL_NAME (t));
 467           break;
 468
 469         case INTEGER_TYPE:
 470           data_type = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (t)));
 471           /* Normally, `unsigned' is part of the deal.  Not so if it comes
 472              with `const' or `volatile'.  */
 473           if (TREE_UNSIGNED (t) && (TYPE_READONLY (t) || TYPE_VOLATILE (t)))
 474             data_type = concat ("unsigned ", data_type);
 475           break;
 476
 477         case REAL_TYPE:
 478           data_type = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (t)));
 479           break;
 480
 481         case VOID_TYPE:
 482           data_type = "void";
 483           break;
 484
 485         default:
 486           abort ();
 487         }
 488     }
 489   if (TYPE_READONLY (t))
 490     ret_val = concat ("const ", ret_val);
 491   if (TYPE_VOLATILE (t))
 492     ret_val = concat ("volatile ", ret_val);
 493   return ret_val;
 494 }
 495
 496 /* Generate a string (source) representation of an entire entity declaration
 497    (using some particular style for function types).
 498
 499    The given entity may be either a variable or a function.
 500
 501    If the "is_func_definition" parameter is non-zero, assume that the thing
 502    we are generating a declaration for is a FUNCTION_DECL node which is
 503    associated with a function definition.  In this case, we can assume that
 504    an attached list of DECL nodes for function formal arguments is present.  */
 505
 506 static char*
 507 gen_decl (decl, is_func_definition, style)
 508      tree decl;
 509      int is_func_definition;
 510      formals_style style;
 511 {
 512   char* ret_val;
 513   char* outer_modifier = "";
 514
 515   if (DECL_NAME (decl))
 516     ret_val = IDENTIFIER_POINTER (DECL_NAME (decl));
 517   else
 518     ret_val = "";
 519
 520   /* If we are just generating a list of names of formal parameters, we can
 521      simply return the formal parameter name (with no typing information
 522      attached to it) now.  */
 523
 524   if (style == k_and_r_names)
 525     return ret_val;
 526
 527   /* Note that for the declaration of some entity (either a function or a
 528      data object, like for instance a parameter) if the entity itself was
 529      declared as either const or volatile, then const and volatile properties
 530      are associated with just the declaration of the entity, and *not* with
 531      the `type' of the entity.  Thus, for such declared entities, we have to
 532      generate the qualifiers here.  */
 533
 534   if (TREE_THIS_VOLATILE (decl))
 535     ret_val = concat ("volatile ", ret_val);
 536   if (TREE_READONLY (decl))
 537     ret_val = concat ("const ", ret_val);
 538
 539   data_type = "";
 540
 541   /* For FUNCTION_DECL nodes, there are two possible cases here.  First, if
 542      this FUNCTION_DECL node was generated from a function "definition", then
 543      we will have a list of DECL_NODE's, one for each of the function's formal
 544      parameters.  In this case, we can print out not only the types of each
 545      formal, but also each formal's name.  In the second case, this
 546      FUNCTION_DECL node came from an actual function declaration (and *not*
 547      a definition).  In this case, we do nothing here because the formal
 548      argument type-list will be output later, when the "type" of the function
 549      is added to the string we are building.  Note that the ANSI-style formal
 550      parameter list is considered to be a (suffix) part of the "type" of the
 551      function.  */
 552
 553   if (TREE_CODE (decl) == FUNCTION_DECL && is_func_definition)
 554     {
 555       ret_val = concat (ret_val, gen_formal_list_for_func_def (decl, ansi));
 556
 557       /* Since we have already added in the formals list stuff, here we don't
 558          add the whole "type" of the function we are considering (which
 559          would include its parameter-list info), rather, we only add in
 560          the "type" of the "type" of the function, which is really just
 561          the return-type of the function (and does not include the parameter
 562          list info).  */
 563
 564       ret_val = gen_type (ret_val, TREE_TYPE (TREE_TYPE (decl)), style);
 565     }
 566   else
 567     ret_val = gen_type (ret_val, TREE_TYPE (decl), style);
 568
 569   ret_val = affix_data_type (ret_val);
 570
 571   if (TREE_REGDECL (decl))
 572     ret_val = concat ("register ", ret_val);
 573   if (TREE_PUBLIC (decl))
 574     ret_val = concat ("extern ", ret_val);
 575   if (TREE_CODE (decl) == FUNCTION_DECL && !TREE_PUBLIC (decl))
 576     ret_val = concat ("static ", ret_val);
 577
 578   return ret_val;
 579 }
 580
 581 extern FILE* aux_info_file;
 582
 583 /* Generate and write a new line of info to the aux-info (.X) file.  This
 584    routine is called once for each function declaration, and once for each
 585    function definition (even the implicit ones).  */
 586
 587 void
 588 gen_aux_info_record (fndecl, is_definition, is_implicit, is_prototyped)
 589      tree fndecl;
 590      int is_definition;
 591      int is_implicit;
 592      int is_prototyped;
 593 {
 594   if (flag_gen_aux_info)
 595     {
 596       static int compiled_from_record = 0;
 597
 598       /* Each output .X file must have a header line.  Write one now if we
 599          have not yet done so.  */
 600
 601       if (! compiled_from_record++)
 602         {
 603           /* The first line tells which directory file names are relative to.
 604              Currently, -aux-info works only for files in the working
 605              directory, so just use a `.' as a placeholder for now.  */
 606           fprintf (aux_info_file, "/* compiled from: . */\n");
 607         }
 608
 609       /* Write the actual line of auxiliary info.  */
 610
 611       fprintf (aux_info_file, "/* %s:%d:%c%c */ %s;",
 612                DECL_SOURCE_FILE (fndecl),
 613                DECL_SOURCE_LINE (fndecl),
 614                (is_implicit) ? 'I' : (is_prototyped) ? 'N' : 'O',
 615                (is_definition) ? 'F' : 'C',
 616                gen_decl (fndecl, is_definition, ansi));
 617
 618       /* If this is an explicit function declaration, we need to also write
 619          out an old-style (i.e. K&R) function header, just in case the user
 620          wants to run unprotoize.  */
 621
 622       if (is_definition)
 623         {
 624           fprintf (aux_info_file, " /*%s %s*/",
 625                    gen_formal_list_for_func_def (fndecl, k_and_r_names),
 626                    gen_formal_list_for_func_def (fndecl, k_and_r_decls));
 627         }
 628
 629       fprintf (aux_info_file, "\n");
 630     }
 631 }