dwarf_prototypes.c

   1 /* Copyright Dima Kogan <dima@secretsauce.net>
   2  *
   3  * This program is free software; you can redistribute it and/or modify it under
   4  * the terms of version 2 of the GNU General Public License as published by the
   5  * Free Software Foundation.
   6  *
   7  */
   8 #include <stdio.h>
   9 #include <elfutils/libdwfl.h>
  10 #include <dwarf.h>
  11 #include <stdlib.h>
  12 #include <errno.h>
  13 #include <string.h>
  14
  15 #include "config.h"
  16 #include "prototype.h"
  17 #include "type.h"
  18 #include "param.h"
  19 #include "dict.h"
  20 #include "lens.h"
  21 #include "lens_enum.h"
  22 #include "value.h"
  23 #include "expr.h"
  24 #include "library.h"
  25 #include "options.h"
  26 #include "filter.h"
  27
  28
  29 //#define DUMP_PROTOTYPES
  30
  31 #if 1
  32 #define complain( die, format, ... )                                                    \
  33         fprintf(stderr, "%s() die '%s' @ 0x%lx: " format "\n",          \
  34                         __func__, dwarf_diename(die), dwarf_dieoffset(die),     \
  35                         ##__VA_ARGS__ )
  36 #else
  37 #define complain( die, format, ... )
  38 #endif
  39
  40 #define NEXT_SIBLING(die)                                                               \
  41         int res = dwarf_siblingof(die, die);                            \
  42         if (res == 0) continue;     /* sibling exists    */     \
  43         if (res < 0)  return false; /* error             */     \
  44         break                       /* no sibling exists */
  45
  46 // A map from DIE addresses (Dwarf_Off) to type structures (struct
  47 // arg_type_info*). This is created and filled in at the start of each import,
  48 // and deleted when the import is complete
  49 static struct dict type_hash;
  50
  51
  52 static bool get_type(struct arg_type_info** info, Dwarf_Die* type_die);
  53
  54
  55 #if 0
  56 static bool _dump_dwarf_tree(Dwarf_Die* die, int indent)
  57 {
  58     while (1) {
  59         fprintf(stderr, "%*sprocessing unit: 0x%02x/'%s'\n", indent*4, "",
  60                dwarf_tag(die), dwarf_diename(die));
  61
  62         Dwarf_Die child;
  63         if (dwarf_child(die, &child) == 0) {
  64                         if (!_dump_dwarf_tree(&child, indent+1))
  65                                 return false;
  66         }
  67
  68         SIBLING(die);
  69     }
  70
  71     return true;
  72 }
  73
  74 static bool dump_dwarf_tree(Dwarf_Die* die)
  75 {
  76     return _dump_dwarf_tree( die, 0 );
  77 }
  78 #endif
  79
  80 #ifdef DUMP_PROTOTYPES
  81 static bool _dump_ltrace_tree(const struct arg_type_info* info, int indent)
  82 {
  83         if (indent > 7) {
  84                 fprintf(stderr, "%*s%p ...\n", indent*4, "", (void*)info);
  85                 return true;
  86         }
  87
  88         if (info == NULL) {
  89                 fprintf(stderr, "%*s%p NULL\n", indent*4, "", (void*)info);
  90                 return true;
  91         }
  92
  93         switch (info->type) {
  94         case ARGTYPE_VOID:
  95                 fprintf(stderr, "%*s%p void\n", indent*4, "", (void*)info);
  96                 break;
  97
  98         case ARGTYPE_INT:
  99         case ARGTYPE_UINT:
 100         case ARGTYPE_LONG:
 101         case ARGTYPE_ULONG:
 102         case ARGTYPE_CHAR:
 103         case ARGTYPE_SHORT:
 104         case ARGTYPE_USHORT:
 105         case ARGTYPE_FLOAT:
 106         case ARGTYPE_DOUBLE:
 107                 fprintf(stderr, "%*s%p base\n", indent*4, "", (void*)info);
 108                 break;
 109
 110         case ARGTYPE_ARRAY:
 111                 fprintf(stderr, "%*s%p array. elements not printed\n", indent*4, "",
 112                                 (void*)info);
 113                 break;
 114
 115         case ARGTYPE_POINTER:
 116                 fprintf(stderr, "%*s%p pointer to...\n", indent*4, "", (void*)info);
 117                 _dump_ltrace_tree( info->u.ptr_info.info, indent+1 );
 118                 break;
 119
 120         case ARGTYPE_STRUCT:
 121                 fprintf(stderr, "%*s%p struct...\n", indent*4, "", (void*)info);
 122                 struct struct_field
 123                 {
 124                         struct arg_type_info *info;
 125                         int own_info;
 126                 }* elements = (struct struct_field*)info->u.entries.data;
 127                 unsigned int i;
 128                 for(i=0; i<info->u.entries.size; i++)
 129                         _dump_ltrace_tree( elements[i].info, indent+1 );
 130                 break;
 131
 132         default:
 133                 fprintf(stderr, "%*s%p unknown type\n", indent*4, "", (void*)info);
 134                 return false;;
 135         }
 136
 137         return true;
 138 }
 139
 140 static bool dump_ltrace_tree(const struct arg_type_info* info)
 141 {
 142         return _dump_ltrace_tree( info, 0 );
 143 }
 144 #endif
 145
 146
 147 // pulls a numerical value out of a particular attribute in a die. Returns true
 148 // if successful. The result is returned in *result. Note that this is cast to
 149 // (uint64_t), regardless of the actual type of the input
 150 static bool get_die_numeric(uint64_t* result,
 151                                                         Dwarf_Die *die, unsigned int attr_name)
 152 {
 153         Dwarf_Attribute attr ;
 154
 155         union {
 156                 Dwarf_Word              udata;
 157                 Dwarf_Sword     sdata;
 158                 Dwarf_Addr              addr;
 159                 bool                    flag;
 160         } u;
 161
 162         if (dwarf_attr(die, attr_name, &attr) == NULL)
 163                 return false;
 164
 165         unsigned int form = dwarf_whatform(&attr);
 166
 167 #define PROCESS_NUMERIC(type)                                           \
 168         if (dwarf_form ## type(&attr, &u.type) != 0)    \
 169                 return false;                                                           \
 170         *result = (uint64_t)u.type;                                             \
 171         return true
 172
 173
 174         switch (form) {
 175         case DW_FORM_addr:
 176                 PROCESS_NUMERIC(addr);
 177
 178         case DW_FORM_data1:
 179         case DW_FORM_data2:
 180         case DW_FORM_data4:
 181         case DW_FORM_data8:
 182         case DW_FORM_udata:
 183                 PROCESS_NUMERIC(udata);
 184
 185         case DW_FORM_sdata:
 186                 PROCESS_NUMERIC(sdata);
 187
 188         case DW_FORM_flag:
 189                 PROCESS_NUMERIC(flag);
 190
 191         default:
 192                 complain(die, "Unknown numeric form %d for attr_name: %d", form, attr_name);
 193                 return false;
 194         }
 195 #undef PROCESS_NUMERIC
 196 }
 197
 198 static bool get_integer_base_type(enum arg_type* type, int byte_size, bool is_signed)
 199 {
 200         switch (byte_size) {
 201         case sizeof(char):
 202                 *type = ARGTYPE_CHAR;
 203                 return true;
 204
 205         case sizeof(short):
 206                 *type = is_signed ? ARGTYPE_SHORT : ARGTYPE_USHORT;
 207                 return true;
 208
 209         case sizeof(int):
 210                 *type = is_signed ? ARGTYPE_INT : ARGTYPE_UINT;
 211                 return true;
 212
 213         case sizeof(long):
 214                 *type = is_signed ? ARGTYPE_LONG : ARGTYPE_ULONG;
 215                 return true;
 216
 217         default:
 218                 return false;
 219         }
 220 }
 221
 222 static enum arg_type get_base_type(Dwarf_Die* die)
 223 {
 224         int64_t encoding;
 225         if( !get_die_numeric((uint64_t*)&encoding, die, DW_AT_encoding))
 226                 return ARGTYPE_VOID;
 227
 228         if (encoding == DW_ATE_void)
 229                 return ARGTYPE_VOID;
 230
 231         if (encoding == DW_ATE_signed_char || encoding == DW_ATE_unsigned_char)
 232                 return ARGTYPE_CHAR;
 233
 234                 uint64_t byte_size;
 235                 if (!get_die_numeric(&byte_size, die, DW_AT_byte_size))
 236                         return ARGTYPE_VOID;
 237
 238         if (encoding == DW_ATE_signed   ||
 239                 encoding == DW_ATE_unsigned ||
 240                 encoding == DW_ATE_boolean) {
 241
 242                 bool is_signed = (encoding == DW_ATE_signed);
 243
 244                 enum arg_type type;
 245                 if(!get_integer_base_type(&type, (int)byte_size, is_signed)) {
 246                         complain(die, "Unknown integer base type. Using 'void'");
 247                         return ARGTYPE_VOID;
 248                 }
 249                 return type;
 250         }
 251
 252         if (encoding == DW_ATE_float) {
 253                 switch (byte_size) {
 254                 case sizeof(float):
 255                         return ARGTYPE_FLOAT;
 256
 257                 case sizeof(double):
 258                         return ARGTYPE_DOUBLE;
 259
 260                 default:
 261                         // things like long doubles. ltrace has no support yet, so I just
 262                         // say "void"
 263                         return ARGTYPE_VOID;
 264                 }
 265         }
 266
 267 #if 0
 268         if (encoding == DW_ATE_complex_float) {
 269                 switch (byte_size) {
 270                 case 2*sizeof(float):
 271                         return ARGTYPE_FLOAT;
 272
 273                 case 2*sizeof(double):
 274                         return ARGTYPE_DOUBLE;
 275
 276                 default:
 277                         // things like long doubles. ltrace has no support yet, so I just
 278                         // say "void"
 279                         return ARGTYPE_VOID;
 280                 }
 281         }
 282 #endif
 283
 284         // Unknown encoding. I just say void
 285         complain(die, "Unknown base type. Returning 'void'");
 286         return ARGTYPE_VOID;
 287 }
 288
 289 static bool get_type_die(Dwarf_Die* type_die, Dwarf_Die* die)
 290 {
 291         Dwarf_Attribute attr;
 292         return
 293                 dwarf_attr(die, DW_AT_type, &attr) != NULL &&
 294                 dwarf_formref_die(&attr, type_die) != NULL;
 295 }
 296
 297 static size_t dwarf_die_hash(const void* x)
 298 {
 299         return *(const Dwarf_Off*)x;
 300 }
 301 static int dwarf_die_eq(const void* a, const void* b)
 302 {
 303         return *(const Dwarf_Off*)a == *(const Dwarf_Off*)b;
 304 }
 305
 306 static bool get_enum(struct arg_type_info* enum_info, Dwarf_Die* parent)
 307 {
 308         uint64_t byte_size;
 309         if (!get_die_numeric(&byte_size, parent, DW_AT_byte_size)) {
 310                 // No byte size given, assume 'int'
 311                 enum_info->type = ARGTYPE_INT;
 312         } else {
 313                 if(!get_integer_base_type(&enum_info->type, (int)byte_size, true)) {
 314                         complain(parent, "Unknown integer base type. Using 'int'");
 315                         enum_info->type = ARGTYPE_INT;
 316                 }
 317         }
 318
 319         struct enum_lens *lens = calloc(1, sizeof(struct enum_lens));
 320         if (lens == NULL) {
 321                 complain(parent, "alloc error");
 322                 return false;
 323         }
 324         lens_init_enum(lens);
 325         enum_info->lens = &lens->super;
 326
 327         Dwarf_Die die;
 328         if (dwarf_child(parent, &die) != 0) {
 329                 // empty enum. we're done
 330                 return true;
 331         }
 332
 333         while(1) {
 334                 complain(&die, "enum element: 0x%02x/'%s'", dwarf_tag(&die),
 335                                  dwarf_diename(&die));
 336
 337                 if (dwarf_tag(&die) != DW_TAG_enumerator) {
 338                         complain(&die, "Enums can have ONLY DW_TAG_enumerator elements");
 339                         return false;
 340                 }
 341
 342                 if (!dwarf_hasattr(&die, DW_AT_const_value)) {
 343                         complain(&die, "Enums MUST have DW_AT_const_value values");
 344                         return false;
 345                 }
 346
 347                 const char* key = dwarf_diename(&die);
 348                 if (key == NULL) {
 349                         complain(&die, "Enums must have a DW_AT_name key");
 350                         return false;
 351                 }
 352                 const char* dupkey = strdup(key);
 353                 if (dupkey == NULL) {
 354                         complain(&die, "Couldn't duplicate enum key");
 355                         return false;
 356                 }
 357
 358                 struct value* value = calloc( 1, sizeof(struct value));
 359                 if (value == NULL) {
 360                         complain(&die, "Couldn't alloc enum value");
 361                         return false;
 362                 }
 363
 364                 value_init_detached(value, NULL, type_get_simple( enum_info->type ), 0);
 365                 uint64_t enum_value;
 366                 if (!get_die_numeric(&enum_value, &die, DW_AT_const_value)) {
 367                         complain(&die, "Couldn't get enum value");
 368                         return false;
 369                 }
 370
 371                 value_set_word(value, (long)enum_value);
 372
 373                 if (lens_enum_add( lens, dupkey, 0, value, 0 )) {
 374                         complain(&die, "Couldn't add enum element");
 375                         return false;
 376                 }
 377
 378                 NEXT_SIBLING(&die);
 379         }
 380
 381         return true;
 382 }
 383
 384 static bool get_array(struct arg_type_info* array_info, Dwarf_Die* parent)
 385 {
 386         Dwarf_Die type_die;
 387         if (!get_type_die( &type_die, parent )) {
 388                 complain( parent, "Array has unknown type" );
 389                 return false;
 390         }
 391
 392         struct arg_type_info* info;
 393         if (!get_type( &info, &type_die )) {
 394                 complain( parent, "Couldn't figure out array's type" );
 395                 return false;
 396         }
 397
 398         Dwarf_Die subrange;
 399         if (dwarf_child(parent, &subrange) != 0) {
 400                 complain(parent,
 401                                  "Array must have a DW_TAG_subrange_type child, but has none");
 402                 return false;
 403         }
 404
 405         Dwarf_Die next_subrange;
 406         if (dwarf_siblingof(&subrange, &next_subrange) <= 0) {
 407                 complain(parent,
 408                                  "Array must have exactly one DW_TAG_subrange_type child");
 409                 return false;
 410         }
 411
 412         if (dwarf_hasattr(&subrange, DW_AT_lower_bound)) {
 413                 uint64_t lower_bound;
 414                 if (!get_die_numeric(&lower_bound, &subrange, DW_AT_lower_bound)) {
 415                         complain( parent, "Couldn't read lower bound");
 416                         return false;
 417                 }
 418
 419                 if (lower_bound != 0) {
 420                         complain( parent,
 421                                           "Array subrange has a nonzero lower bound. Don't know what to do");
 422                         return false;
 423                 }
 424         }
 425
 426         uint64_t N;
 427         if (!dwarf_hasattr(&subrange, DW_AT_upper_bound)) {
 428                 // no upper bound is defined. This is probably a variable-width array,
 429                 // and I don't know how long it is. Let's say 0 to be safe
 430                 N = 0;
 431         }
 432         else
 433         {
 434                 if (!get_die_numeric(&N, &subrange, DW_AT_upper_bound)) {
 435                         complain( parent, "Couldn't read upper bound");
 436                         return false;
 437                 }
 438                 N++;
 439         }
 440
 441         // I'm not checking the subrange type. It should be some sort of integer,
 442         // and I don't know what it would mean for it to be something else
 443
 444         struct value* value = calloc( 1, sizeof(struct value));
 445         if (value == NULL) {
 446                 complain(&subrange, "Couldn't alloc length value");
 447                 return false;
 448         }
 449         value_init_detached(value, NULL, type_get_simple( ARGTYPE_INT ), 0);
 450         value_set_word(value, N );
 451
 452         struct expr_node* length = calloc( 1, sizeof(struct expr_node));
 453         if (length == NULL) {
 454                 complain(&subrange, "Couldn't alloc length expr");
 455                 return false;
 456         }
 457         expr_init_const(length, value);
 458
 459         type_init_array(array_info, info, 0, length, 0 );
 460
 461         return true;
 462 }
 463
 464 static bool get_structure(struct arg_type_info* struct_info, Dwarf_Die* parent)
 465 {
 466         type_init_struct(struct_info);
 467
 468         Dwarf_Die die;
 469         if (dwarf_child(parent, &die) != 0) {
 470                 // no elements; we're done
 471                 return true;
 472         }
 473
 474         while(1) {
 475                 complain(&die, "member: 0x%02x", dwarf_tag(&die));
 476
 477                 if (dwarf_tag(&die) != DW_TAG_member) {
 478                         complain(&die, "Structure can have ONLY DW_TAG_member");
 479                         return false;
 480                 }
 481
 482                 Dwarf_Die type_die;
 483                 if (!get_type_die( &type_die, &die )) {
 484                         complain( &die, "Couldn't get type of element");
 485                         return false;
 486                 }
 487
 488                 struct arg_type_info* member_info = NULL;
 489                 if (!get_type( &member_info, &type_die )) {
 490                         complain(&die, "Couldn't parse type from DWARF data");
 491                         return false;
 492                 }
 493                 type_struct_add( struct_info, member_info, 0 );
 494
 495                 NEXT_SIBLING(&die);
 496         }
 497
 498         return true;
 499 }
 500
 501 // Reads the type in the die into the given structure
 502 // Returns true on sucess
 503 static bool get_type(struct arg_type_info** info, Dwarf_Die* type_die)
 504 {
 505         Dwarf_Off die_offset = dwarf_dieoffset(type_die);
 506         struct arg_type_info** found_type = dict_find(&type_hash, &die_offset );
 507         if (found_type != NULL) {
 508                 *info = *found_type;
 509                 complain(type_die, "Read pre-computed type: %p", *info);
 510                 return true;
 511         }
 512
 513         Dwarf_Die next_die;
 514
 515         switch (dwarf_tag(type_die)) {
 516         case DW_TAG_base_type:
 517                 *info = type_get_simple( get_base_type( type_die ));
 518                 complain(type_die, "Storing base type: %p", *info);
 519                 dict_insert( &type_hash, &die_offset, info );
 520                 return true;
 521
 522         case DW_TAG_subroutine_type:
 523         case DW_TAG_inlined_subroutine:
 524                 // function pointers are stored as void*. If ltrace tries to dereference
 525                 // these, it'll get a segfault
 526                 *info = type_get_simple( ARGTYPE_VOID );
 527                 complain(type_die, "Storing subroutine type: %p", *info);
 528                 dict_insert( &type_hash, &die_offset, info );
 529                 return true;
 530
 531         case DW_TAG_pointer_type:
 532
 533                 if (!get_type_die(&next_die, type_die )) {
 534                         // the pointed-to type isn't defined, so I report a void*
 535                         *info = type_get_simple( ARGTYPE_VOID );
 536                         complain(type_die, "Storing void-pointer type: %p", *info);
 537                         dict_insert( &type_hash, &die_offset, info );
 538                         return true;
 539                 }
 540
 541                 *info = calloc( 1, sizeof(struct arg_type_info));
 542                 if (*info == NULL) {
 543                         complain(type_die, "alloc error");
 544                         return false;
 545                 }
 546                 type_init_pointer(*info, NULL, 0);
 547
 548                 complain(type_die, "Storing pointer type: %p", *info);
 549                 dict_insert( &type_hash, &die_offset, info );
 550                 return get_type( &(*info)->u.ptr_info.info, &next_die );
 551
 552         case DW_TAG_structure_type:
 553                 *info = calloc( 1, sizeof(struct arg_type_info));
 554                 if (*info == NULL) {
 555                         complain(type_die, "alloc error");
 556                         return false;
 557                 }
 558
 559                 complain(type_die, "Storing struct type: %p", *info);
 560                 dict_insert( &type_hash, &die_offset, info );
 561                 return get_structure( *info, type_die );
 562
 563
 564         case DW_TAG_typedef:
 565         case DW_TAG_const_type:
 566         case DW_TAG_volatile_type: {
 567                 // Various tags are simply pass-through, so I just keep going
 568                 bool res = true;
 569                 if (get_type_die(&next_die, type_die )) {
 570                         complain(type_die, "Storing const/typedef type: %p", *info);
 571                         res = get_type( info, &next_die );
 572                 } else {
 573                         // no type. Use 'void'. Normally I'd think this is bogus, but stdio
 574                         // typedefs something to void
 575                         *info = type_get_simple( ARGTYPE_VOID );
 576                         complain(type_die, "Storing void type: %p", *info);
 577                 }
 578                 if (res)
 579                         dict_insert( &type_hash, &die_offset, info );
 580                 return res;
 581         }
 582
 583         case DW_TAG_enumeration_type:
 584                 // We have an enumeration. This has type "int", but has a particular
 585                 // lens to handle the enum
 586                 *info = calloc( 1, sizeof(struct arg_type_info));
 587                 if (*info == NULL) {
 588                         complain(type_die, "alloc error");
 589                         return false;
 590                 }
 591
 592                 complain(type_die, "Storing enum int: %p", *info);
 593                 dict_insert( &type_hash, &die_offset, info );
 594                 return get_enum( *info, type_die );
 595
 596         case DW_TAG_array_type:
 597                 *info = calloc( 1, sizeof(struct arg_type_info));
 598                 if (*info == NULL) {
 599                         complain(type_die, "alloc error");
 600                         return false;
 601                 }
 602
 603                 complain(type_die, "Storing array: %p", *info);
 604                 dict_insert( &type_hash, &die_offset, info );
 605                 return get_array( *info, type_die );
 606
 607         case DW_TAG_union_type:
 608                 *info = type_get_simple( ARGTYPE_VOID );
 609                 complain(type_die, "Storing union-as-void type: %p", *info);
 610                 return true;
 611
 612         default:
 613                 complain(type_die, "Unknown type tag 0x%x", dwarf_tag(type_die));
 614                 break;
 615         }
 616
 617         return false;
 618 }
 619
 620 static bool get_prototype(struct prototype* proto, Dwarf_Die* subroutine)
 621 {
 622         // First, look at the return type. This is stored in a DW_AT_type tag in the
 623         // subroutine DIE. If there is no such tag, this function returns void
 624         Dwarf_Die return_type_die;
 625         if (!get_type_die(&return_type_die, subroutine )) {
 626                 proto->return_info = type_get_simple( ARGTYPE_VOID );
 627                 proto->own_return_info = 0;
 628         } else {
 629                 proto->return_info = calloc( 1, sizeof( struct arg_type_info ));
 630                 if (proto->return_info == NULL) {
 631                         complain(subroutine, "Couldn't alloc return type");
 632                         return false;
 633                 }
 634                 proto->own_return_info = 0;
 635
 636                 if (!get_type( &proto->return_info, &return_type_die )) {
 637                         complain(subroutine, "Couldn't get return type");
 638                         return false;
 639                 }
 640         }
 641
 642
 643         // Now look at the arguments
 644         Dwarf_Die arg_die;
 645         if (dwarf_child(subroutine, &arg_die) != 0) {
 646                 // no args. We're done
 647                 return true;
 648         }
 649
 650         while(1) {
 651                 if (dwarf_tag(&arg_die) == DW_TAG_formal_parameter) {
 652
 653                         complain(&arg_die, "arg: 0x%02x", dwarf_tag(&arg_die));
 654
 655                         Dwarf_Die type_die;
 656                         if (!get_type_die(&type_die, &arg_die )) {
 657                                 complain(&arg_die, "Couldn't get the argument type die");
 658                                 return false;
 659                         }
 660
 661                         struct arg_type_info* arg_type_info = NULL;
 662                         if (!get_type( &arg_type_info, &type_die )) {
 663                                 complain(&arg_die, "Couldn't parse arg type from DWARF data");
 664                                 return false;
 665                         }
 666
 667                         struct param param;
 668                         param_init_type(&param, arg_type_info, 0);
 669                         if (prototype_push_param(proto, &param) <0) {
 670                                 complain(&arg_die, "couldn't add argument to the prototype");
 671                                 return false;
 672                         }
 673
 674 #ifdef DUMP_PROTOTYPES
 675                         fprintf(stderr, "Adding argument:\n");
 676                         dump_ltrace_tree(arg_type_info);
 677 #endif
 678                 }
 679
 680                 NEXT_SIBLING(&arg_die);
 681         }
 682
 683         return true;
 684 }
 685
 686 static bool import_subprogram(struct protolib* plib, struct library* lib,
 687                                                           Dwarf_Die* die)
 688 {
 689         // I use the linkage function name if there is one, otherwise the
 690         // plain name
 691         const char* function_name = NULL;
 692         Dwarf_Attribute attr;
 693         if (dwarf_attr(die, DW_AT_linkage_name, &attr) != NULL)
 694                 function_name = dwarf_formstring(&attr);
 695         if (function_name == NULL)
 696                 function_name = dwarf_diename(die);
 697         if (function_name == NULL) {
 698                 complain(die, "Function has no name. Not importing" );
 699                 return true;
 700         }
 701
 702
 703         complain(die, "subroutine_type: 0x%02x; function '%s'",
 704                          dwarf_tag(die), function_name);
 705
 706         struct prototype* proto =
 707                 protolib_lookup_prototype(plib, function_name, false );
 708
 709         if (proto != NULL) {
 710                 complain(die, "Prototype already exists. Skipping");
 711                 return true;
 712         }
 713
 714         if (!filter_matches_symbol(options.plt_filter,    function_name, lib) &&
 715                 !filter_matches_symbol(options.static_filter, function_name, lib) &&
 716                 !filter_matches_symbol(options.export_filter, function_name, lib)) {
 717                 complain(die, "Prototype not requested by any filter");
 718                 return true;
 719         }
 720
 721         proto = malloc(sizeof(struct prototype));
 722         if (proto == NULL) {
 723                 complain(die, "couldn't alloc prototype");
 724                 return false;
 725         }
 726         prototype_init( proto );
 727
 728         if (!get_prototype(proto, die )) {
 729                 complain(die, "couldn't get prototype");
 730                 return false;
 731         }
 732
 733         protolib_add_prototype(plib, function_name, 0, proto);
 734         return true;
 735 }
 736
 737 static bool process_die_compileunit(struct protolib* plib, struct library* lib,
 738                                                                         Dwarf_Die* parent)
 739 {
 740         Dwarf_Die die;
 741         if (dwarf_child(parent, &die) != 0) {
 742                 // no child nodes, so nothing to do
 743                 return true;
 744         }
 745
 746         while (1) {
 747                 if (dwarf_tag(&die) == DW_TAG_subprogram)
 748                         if(!import_subprogram(plib, lib, &die))
 749                                 return false;
 750
 751                 NEXT_SIBLING(&die);
 752         }
 753
 754         return true;
 755 }
 756
 757 static bool import(struct protolib* plib, struct library* lib, Dwfl* dwfl)
 758 {
 759         dict_init(&type_hash, sizeof(Dwarf_Off), sizeof(struct arg_type_info*),
 760                           dwarf_die_hash, dwarf_die_eq, NULL );
 761
 762         Dwarf_Addr bias;
 763     Dwarf_Die* die = NULL;
 764     while ((die = dwfl_nextcu(dwfl, die, &bias)) != NULL) {
 765         if (dwarf_tag(die) == DW_TAG_compile_unit) {
 766             if (!process_die_compileunit(plib, lib, die)) {
 767                 complain(die, "Error reading compile unit");
 768                                 exit(1);
 769                                 return false;
 770             }
 771         } else {
 772             complain(die, "DW_TAG_compile_unit expected");
 773                         exit(1);
 774             return false;
 775         }
 776     }
 777
 778         dict_destroy( &type_hash, NULL, NULL, NULL );
 779         return true;
 780 }
 781
 782 bool import_DWARF_prototypes(struct protolib* plib, struct library* lib,
 783                                                          Dwfl *dwfl)
 784 {
 785         if (plib == NULL) {
 786                 plib = protolib_cache_default(&g_protocache, lib->soname, 0);
 787                 if (plib == NULL) {
 788                         fprintf(stderr, "Error loading protolib %s: %s.\n",
 789                                         lib->soname, strerror(errno));
 790                 }
 791         }
 792
 793         return import(plib, lib, dwfl);
 794 }
 795
 796 /*
 797 - I handle static functions now. Should I? Those do not have DW_AT_external==1
 798
 799 - should process existing prototypes to make sure they match
 800
 801 - what do function pointers look like? I'm doing void*
 802
 803 - unions
 804
 805 - all my *allocs leak
 806
 807
 808 */