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 static bool get_type(struct arg_type_info** info, Dwarf_Die* type_die, struct protolib* plib,
  47                                          struct dict* type_dieoffset_hash);
  48
  49
  50 #if 0
  51 static bool _dump_dwarf_tree(Dwarf_Die* die, int indent)
  52 {
  53     while (1) {
  54         fprintf(stderr, "%*sprocessing unit: 0x%02x/'%s'\n", indent*4, "",
  55                dwarf_tag(die), dwarf_diename(die));
  56
  57         Dwarf_Die child;
  58         if (dwarf_child(die, &child) == 0) {
  59                         if (!_dump_dwarf_tree(&child, indent+1))
  60                                 return false;
  61         }
  62
  63         SIBLING(die);
  64     }
  65
  66     return true;
  67 }
  68
  69 static bool dump_dwarf_tree(Dwarf_Die* die)
  70 {
  71     return _dump_dwarf_tree(die, 0);
  72 }
  73 #endif
  74
  75 #ifdef DUMP_PROTOTYPES
  76 static bool _dump_ltrace_tree(const struct arg_type_info* info, int indent)
  77 {
  78         if (indent > 7) {
  79                 fprintf(stderr, "%*s%p ...\n", indent*4, "", (void*)info);
  80                 return true;
  81         }
  82
  83         if (info == NULL) {
  84                 fprintf(stderr, "%*s%p NULL\n", indent*4, "", (void*)info);
  85                 return true;
  86         }
  87
  88         switch (info->type) {
  89         case ARGTYPE_VOID:
  90                 fprintf(stderr, "%*s%p void\n", indent*4, "", (void*)info);
  91                 break;
  92
  93         case ARGTYPE_INT:
  94         case ARGTYPE_UINT:
  95         case ARGTYPE_LONG:
  96         case ARGTYPE_ULONG:
  97         case ARGTYPE_CHAR:
  98         case ARGTYPE_SHORT:
  99         case ARGTYPE_USHORT:
 100         case ARGTYPE_FLOAT:
 101         case ARGTYPE_DOUBLE:
 102                 fprintf(stderr, "%*s%p base\n", indent*4, "", (void*)info);
 103                 break;
 104
 105         case ARGTYPE_ARRAY:
 106                 fprintf(stderr, "%*s%p array. elements not printed\n", indent*4, "",
 107                                 (void*)info);
 108                 break;
 109
 110         case ARGTYPE_POINTER:
 111                 fprintf(stderr, "%*s%p pointer to...\n", indent*4, "", (void*)info);
 112                 _dump_ltrace_tree(info->u.ptr_info.info, indent+1);
 113                 break;
 114
 115         case ARGTYPE_STRUCT:
 116                 fprintf(stderr, "%*s%p struct...\n", indent*4, "", (void*)info);
 117                 struct struct_field
 118                 {
 119                         struct arg_type_info *info;
 120                         int own_info;
 121                 }* elements = (struct struct_field*)info->u.entries.data;
 122                 unsigned int i;
 123                 for(i=0; i<info->u.entries.size; i++)
 124                         _dump_ltrace_tree(elements[i].info, indent+1);
 125                 break;
 126
 127         default:
 128                 fprintf(stderr, "%*s%p unknown type\n", indent*4, "", (void*)info);
 129                 return false;;
 130         }
 131
 132         return true;
 133 }
 134
 135 static bool dump_ltrace_tree(const struct arg_type_info* info)
 136 {
 137         return _dump_ltrace_tree(info, 0);
 138 }
 139 #endif
 140
 141
 142 // pulls a numerical value out of a particular attribute in a die. Returns true
 143 // if successful. The result is returned in *result. Note that this is cast to
 144 // (uint64_t), regardless of the actual type of the input
 145 static bool get_die_numeric(uint64_t* result,
 146                                                         Dwarf_Die *die, unsigned int attr_name)
 147 {
 148         Dwarf_Attribute attr ;
 149
 150         union {
 151                 Dwarf_Word              udata;
 152                 Dwarf_Sword     sdata;
 153                 Dwarf_Addr              addr;
 154                 bool                    flag;
 155         } u;
 156
 157         if (dwarf_attr(die, attr_name, &attr) == NULL)
 158                 return false;
 159
 160         unsigned int form = dwarf_whatform(&attr);
 161
 162 #define PROCESS_NUMERIC(type)                                           \
 163         if (dwarf_form ## type(&attr, &u.type) != 0)    \
 164                 return false;                                                           \
 165         *result = (uint64_t)u.type;                                             \
 166         return true
 167
 168
 169         switch (form) {
 170         case DW_FORM_addr:
 171                 PROCESS_NUMERIC(addr);
 172
 173         case DW_FORM_data1:
 174         case DW_FORM_data2:
 175         case DW_FORM_data4:
 176         case DW_FORM_data8:
 177         case DW_FORM_udata:
 178                 PROCESS_NUMERIC(udata);
 179
 180         case DW_FORM_sdata:
 181                 PROCESS_NUMERIC(sdata);
 182
 183         case DW_FORM_flag:
 184                 PROCESS_NUMERIC(flag);
 185
 186         default:
 187                 complain(die, "Unknown numeric form %d for attr_name: %d", form, attr_name);
 188                 return false;
 189         }
 190 #undef PROCESS_NUMERIC
 191 }
 192
 193 static bool get_integer_base_type(enum arg_type* type, int byte_size, bool is_signed)
 194 {
 195         switch (byte_size) {
 196         case sizeof(char):
 197                 *type = ARGTYPE_CHAR;
 198                 return true;
 199
 200         case sizeof(short):
 201                 *type = is_signed ? ARGTYPE_SHORT : ARGTYPE_USHORT;
 202                 return true;
 203
 204         case sizeof(int):
 205                 *type = is_signed ? ARGTYPE_INT : ARGTYPE_UINT;
 206                 return true;
 207
 208         case sizeof(long):
 209                 *type = is_signed ? ARGTYPE_LONG : ARGTYPE_ULONG;
 210                 return true;
 211
 212         default:
 213                 return false;
 214         }
 215 }
 216
 217 static enum arg_type get_base_type(Dwarf_Die* die)
 218 {
 219         int64_t encoding;
 220         if(!get_die_numeric((uint64_t*)&encoding, die, DW_AT_encoding))
 221                 return ARGTYPE_VOID;
 222
 223         if (encoding == DW_ATE_void)
 224                 return ARGTYPE_VOID;
 225
 226         if (encoding == DW_ATE_signed_char || encoding == DW_ATE_unsigned_char)
 227                 return ARGTYPE_CHAR;
 228
 229                 uint64_t byte_size;
 230                 if (!get_die_numeric(&byte_size, die, DW_AT_byte_size))
 231                         return ARGTYPE_VOID;
 232
 233         if (encoding == DW_ATE_signed   ||
 234                 encoding == DW_ATE_unsigned ||
 235                 encoding == DW_ATE_boolean) {
 236
 237                 bool is_signed = (encoding == DW_ATE_signed);
 238
 239                 enum arg_type type;
 240                 if(!get_integer_base_type(&type, (int)byte_size, is_signed)) {
 241                         complain(die, "Unknown integer base type. Using 'void'");
 242                         return ARGTYPE_VOID;
 243                 }
 244                 return type;
 245         }
 246
 247         if (encoding == DW_ATE_float) {
 248                 switch (byte_size) {
 249                 case sizeof(float):
 250                         return ARGTYPE_FLOAT;
 251
 252                 case sizeof(double):
 253                         return ARGTYPE_DOUBLE;
 254
 255                 default:
 256                         // things like long doubles. ltrace has no support yet, so I just
 257                         // say "void"
 258                         return ARGTYPE_VOID;
 259                 }
 260         }
 261
 262 #if 0
 263         if (encoding == DW_ATE_complex_float) {
 264                 switch (byte_size) {
 265                 case 2*sizeof(float):
 266                         return ARGTYPE_FLOAT;
 267
 268                 case 2*sizeof(double):
 269                         return ARGTYPE_DOUBLE;
 270
 271                 default:
 272                         // things like long doubles. ltrace has no support yet, so I just
 273                         // say "void"
 274                         return ARGTYPE_VOID;
 275                 }
 276         }
 277 #endif
 278
 279         // Unknown encoding. I just say void
 280         complain(die, "Unknown base type. Returning 'void'");
 281         return ARGTYPE_VOID;
 282 }
 283
 284 static bool get_type_die(Dwarf_Die* type_die, Dwarf_Die* die)
 285 {
 286         Dwarf_Attribute attr;
 287         return
 288                 dwarf_attr(die, DW_AT_type, &attr) != NULL &&
 289                 dwarf_formref_die(&attr, type_die) != NULL;
 290 }
 291
 292 static size_t dwarf_die_hash(const void* x)
 293 {
 294         return *(const Dwarf_Off*)x;
 295 }
 296 static int dwarf_die_eq(const void* a, const void* b)
 297 {
 298         return *(const Dwarf_Off*)a == *(const Dwarf_Off*)b;
 299 }
 300
 301 static bool get_enum(struct arg_type_info* enum_info, Dwarf_Die* parent)
 302 {
 303         uint64_t byte_size;
 304         if (!get_die_numeric(&byte_size, parent, DW_AT_byte_size)) {
 305                 // No byte size given, assume 'int'
 306                 enum_info->type = ARGTYPE_INT;
 307         } else {
 308                 if(!get_integer_base_type(&enum_info->type, (int)byte_size, true)) {
 309                         complain(parent, "Unknown integer base type. Using 'int'");
 310                         enum_info->type = ARGTYPE_INT;
 311                 }
 312         }
 313
 314         struct enum_lens *lens = calloc(1, sizeof(struct enum_lens));
 315         if (lens == NULL) {
 316                 complain(parent, "alloc error");
 317                 return false;
 318         }
 319         lens_init_enum(lens);
 320         enum_info->lens = &lens->super;
 321
 322         Dwarf_Die die;
 323         if (dwarf_child(parent, &die) != 0) {
 324                 // empty enum. we're done
 325                 return true;
 326         }
 327
 328         while(1) {
 329                 complain(&die, "enum element: 0x%02x/'%s'", dwarf_tag(&die),
 330                                  dwarf_diename(&die));
 331
 332                 if (dwarf_tag(&die) != DW_TAG_enumerator) {
 333                         complain(&die, "Enums can have ONLY DW_TAG_enumerator elements");
 334                         return false;
 335                 }
 336
 337                 if (!dwarf_hasattr(&die, DW_AT_const_value)) {
 338                         complain(&die, "Enums MUST have DW_AT_const_value values");
 339                         return false;
 340                 }
 341
 342                 const char* key = dwarf_diename(&die);
 343                 if (key == NULL) {
 344                         complain(&die, "Enums must have a DW_AT_name key");
 345                         return false;
 346                 }
 347                 const char* dupkey = strdup(key);
 348                 if (dupkey == NULL) {
 349                         complain(&die, "Couldn't duplicate enum key");
 350                         return false;
 351                 }
 352
 353                 struct value* value = calloc(1, sizeof(struct value));
 354                 if (value == NULL) {
 355                         complain(&die, "Couldn't alloc enum value");
 356                         return false;
 357                 }
 358
 359                 value_init_detached(value, NULL, type_get_simple(enum_info->type), 0);
 360                 uint64_t enum_value;
 361                 if (!get_die_numeric(&enum_value, &die, DW_AT_const_value)) {
 362                         complain(&die, "Couldn't get enum value");
 363                         return false;
 364                 }
 365
 366                 value_set_word(value, (long)enum_value);
 367
 368                 if (lens_enum_add(lens, dupkey, 0, value, 0)) {
 369                         complain(&die, "Couldn't add enum element");
 370                         return false;
 371                 }
 372
 373                 NEXT_SIBLING(&die);
 374         }
 375
 376         return true;
 377 }
 378
 379 static bool get_array(struct arg_type_info* array_info, Dwarf_Die* parent, struct protolib* plib,
 380                                           struct dict* type_dieoffset_hash)
 381 {
 382         Dwarf_Die type_die;
 383         if (!get_type_die(&type_die, parent)) {
 384                 complain(parent, "Array has unknown type");
 385                 return false;
 386         }
 387
 388         struct arg_type_info* info;
 389         if (!get_type(&info, &type_die, plib, type_dieoffset_hash)) {
 390                 complain(parent, "Couldn't figure out array's type");
 391                 return false;
 392         }
 393
 394         Dwarf_Die subrange;
 395         if (dwarf_child(parent, &subrange) != 0) {
 396                 complain(parent,
 397                                  "Array must have a DW_TAG_subrange_type child, but has none");
 398                 return false;
 399         }
 400
 401         Dwarf_Die next_subrange;
 402         if (dwarf_siblingof(&subrange, &next_subrange) <= 0) {
 403                 complain(parent,
 404                                  "Array must have exactly one DW_TAG_subrange_type child");
 405                 return false;
 406         }
 407
 408         if (dwarf_hasattr(&subrange, DW_AT_lower_bound)) {
 409                 uint64_t lower_bound;
 410                 if (!get_die_numeric(&lower_bound, &subrange, DW_AT_lower_bound)) {
 411                         complain(parent, "Couldn't read lower bound");
 412                         return false;
 413                 }
 414
 415                 if (lower_bound != 0) {
 416                         complain(parent,
 417                                           "Array subrange has a nonzero lower bound. Don't know what to do");
 418                         return false;
 419                 }
 420         }
 421
 422         uint64_t N;
 423         if (!dwarf_hasattr(&subrange, DW_AT_upper_bound)) {
 424                 // no upper bound is defined. This is probably a variable-width array,
 425                 // and I don't know how long it is. Let's say 0 to be safe
 426                 N = 0;
 427         }
 428         else
 429         {
 430                 if (!get_die_numeric(&N, &subrange, DW_AT_upper_bound)) {
 431                         complain(parent, "Couldn't read upper bound");
 432                         return false;
 433                 }
 434                 N++;
 435         }
 436
 437         // I'm not checking the subrange type. It should be some sort of integer,
 438         // and I don't know what it would mean for it to be something else
 439
 440         struct value* value = calloc(1, sizeof(struct value));
 441         if (value == NULL) {
 442                 complain(&subrange, "Couldn't alloc length value");
 443                 return false;
 444         }
 445         value_init_detached(value, NULL, type_get_simple(ARGTYPE_INT), 0);
 446         value_set_word(value, N);
 447
 448         struct expr_node* length = calloc(1, sizeof(struct expr_node));
 449         if (length == NULL) {
 450                 complain(&subrange, "Couldn't alloc length expr");
 451                 return false;
 452         }
 453         expr_init_const(length, value);
 454
 455         type_init_array(array_info, info, 0, length, 0);
 456
 457         return true;
 458 }
 459
 460 static bool get_structure(struct arg_type_info* struct_info, Dwarf_Die* parent, struct protolib* plib,
 461                                                   struct dict* type_dieoffset_hash)
 462 {
 463         type_init_struct(struct_info);
 464
 465         Dwarf_Die die;
 466         if (dwarf_child(parent, &die) != 0) {
 467                 // no elements; we're done
 468                 return true;
 469         }
 470
 471         while(1) {
 472                 complain(&die, "member: 0x%02x", dwarf_tag(&die));
 473
 474                 if (dwarf_tag(&die) != DW_TAG_member) {
 475                         complain(&die, "Structure can have ONLY DW_TAG_member");
 476                         return false;
 477                 }
 478
 479                 Dwarf_Die type_die;
 480                 if (!get_type_die(&type_die, &die)) {
 481                         complain(&die, "Couldn't get type of element");
 482                         return false;
 483                 }
 484
 485                 struct arg_type_info* member_info = NULL;
 486                 if (!get_type(&member_info, &type_die, plib, type_dieoffset_hash)) {
 487                         complain(&die, "Couldn't parse type from DWARF data");
 488                         return false;
 489                 }
 490                 type_struct_add(struct_info, member_info, 0);
 491
 492                 NEXT_SIBLING(&die);
 493         }
 494
 495         return true;
 496 }
 497
 498 // Reads the type in the die into the given structure
 499 // Returns true on sucess
 500 static bool get_type(struct arg_type_info** info, Dwarf_Die* type_die, struct protolib* plib,
 501                                          struct dict* type_dieoffset_hash)
 502 {
 503         Dwarf_Off die_offset = dwarf_dieoffset(type_die);
 504         struct arg_type_info** found_type = dict_find(type_dieoffset_hash, &die_offset);
 505         if (found_type != NULL) {
 506                 *info = *found_type;
 507                 complain(type_die, "Read pre-computed type: %p", *info);
 508                 return true;
 509         }
 510
 511         const char* type_name = dwarf_diename(type_die);
 512         if (type_name != NULL) {
 513
 514                 struct named_type* already_defined_type =
 515                         protolib_lookup_type(plib, type_name, true);
 516
 517                 if (already_defined_type != NULL) {
 518                         complain(type_die,
 519                                          "Type '%s' defined in a .conf file. Using that instead of DWARF",
 520                                          type_name);
 521                         *info = already_defined_type->info;
 522                         return true;
 523                 }
 524         }
 525
 526         Dwarf_Die next_die;
 527
 528         switch (dwarf_tag(type_die)) {
 529         case DW_TAG_base_type:
 530                 *info = type_get_simple(get_base_type(type_die));
 531                 complain(type_die, "Storing base type: %p", *info);
 532                 dict_insert(type_dieoffset_hash, &die_offset, info);
 533                 return true;
 534
 535         case DW_TAG_subroutine_type:
 536         case DW_TAG_inlined_subroutine:
 537                 // function pointers are stored as void*. If ltrace tries to dereference
 538                 // these, it'll get a segfault
 539                 *info = type_get_simple(ARGTYPE_VOID);
 540                 complain(type_die, "Storing subroutine type: %p", *info);
 541                 dict_insert(type_dieoffset_hash, &die_offset, info);
 542                 return true;
 543
 544         case DW_TAG_pointer_type:
 545
 546                 if (!get_type_die(&next_die, type_die)) {
 547                         // the pointed-to type isn't defined, so I report a void*
 548                         *info = type_get_voidptr();
 549                         complain(type_die, "Storing void-pointer type: %p", *info);
 550                         dict_insert(type_dieoffset_hash, &die_offset, info);
 551                         return true;
 552                 }
 553
 554                 *info = calloc(1, sizeof(struct arg_type_info));
 555                 if (*info == NULL) {
 556                         complain(type_die, "alloc error");
 557                         return false;
 558                 }
 559                 type_init_pointer(*info, NULL, 0);
 560
 561                 complain(type_die, "Storing pointer type: %p", *info);
 562                 dict_insert(type_dieoffset_hash, &die_offset, info);
 563                 return get_type(&(*info)->u.ptr_info.info, &next_die, plib, type_dieoffset_hash);
 564
 565         case DW_TAG_structure_type:
 566                 *info = calloc(1, sizeof(struct arg_type_info));
 567                 if (*info == NULL) {
 568                         complain(type_die, "alloc error");
 569                         return false;
 570                 }
 571
 572                 complain(type_die, "Storing struct type: %p", *info);
 573                 dict_insert(type_dieoffset_hash, &die_offset, info);
 574                 return get_structure(*info, type_die, plib, type_dieoffset_hash);
 575
 576
 577         case DW_TAG_typedef:
 578         case DW_TAG_const_type:
 579         case DW_TAG_volatile_type: {
 580                 // Various tags are simply pass-through, so I just keep going
 581                 bool res = true;
 582                 if (get_type_die(&next_die, type_die)) {
 583                         complain(type_die, "Storing const/typedef type: %p", *info);
 584                         res = get_type(info, &next_die, plib, type_dieoffset_hash);
 585                 } else {
 586                         // no type. Use 'void'. Normally I'd think this is bogus, but stdio
 587                         // typedefs something to void
 588                         *info = type_get_simple(ARGTYPE_VOID);
 589                         complain(type_die, "Storing void type: %p", *info);
 590                 }
 591                 if (res)
 592                         dict_insert(type_dieoffset_hash, &die_offset, info);
 593                 return res;
 594         }
 595
 596         case DW_TAG_enumeration_type:
 597                 // We have an enumeration. This has type "int", but has a particular
 598                 // lens to handle the enum
 599                 *info = calloc(1, sizeof(struct arg_type_info));
 600                 if (*info == NULL) {
 601                         complain(type_die, "alloc error");
 602                         return false;
 603                 }
 604
 605                 complain(type_die, "Storing enum int: %p", *info);
 606                 dict_insert(type_dieoffset_hash, &die_offset, info);
 607                 return get_enum(*info, type_die);
 608
 609         case DW_TAG_array_type:
 610                 *info = calloc(1, sizeof(struct arg_type_info));
 611                 if (*info == NULL) {
 612                         complain(type_die, "alloc error");
 613                         return false;
 614                 }
 615
 616                 complain(type_die, "Storing array: %p", *info);
 617                 dict_insert(type_dieoffset_hash, &die_offset, info);
 618                 return get_array(*info, type_die, plib, type_dieoffset_hash);
 619
 620         case DW_TAG_union_type:
 621                 *info = type_get_simple(ARGTYPE_VOID);
 622                 complain(type_die, "Storing union-as-void type: %p", *info);
 623                 return true;
 624
 625         default:
 626                 complain(type_die, "Unknown type tag 0x%x", dwarf_tag(type_die));
 627                 break;
 628         }
 629
 630         return false;
 631 }
 632
 633 static bool get_prototype(struct prototype* proto, Dwarf_Die* subroutine, struct protolib* plib,
 634                                                   struct dict* type_dieoffset_hash)
 635 {
 636         // First, look at the return type. This is stored in a DW_AT_type tag in the
 637         // subroutine DIE. If there is no such tag, this function returns void
 638         Dwarf_Die return_type_die;
 639         if (!get_type_die(&return_type_die, subroutine)) {
 640                 proto->return_info = type_get_simple(ARGTYPE_VOID);
 641                 proto->own_return_info = 0;
 642         } else {
 643                 proto->return_info = calloc(1, sizeof(struct arg_type_info));
 644                 if (proto->return_info == NULL) {
 645                         complain(subroutine, "Couldn't alloc return type");
 646                         return false;
 647                 }
 648                 proto->own_return_info = 0;
 649
 650                 if (!get_type(&proto->return_info, &return_type_die, plib, type_dieoffset_hash)) {
 651                         complain(subroutine, "Couldn't get return type");
 652                         return false;
 653                 }
 654         }
 655
 656
 657         // Now look at the arguments
 658         Dwarf_Die arg_die;
 659         if (dwarf_child(subroutine, &arg_die) != 0) {
 660                 // no args. We're done
 661                 return true;
 662         }
 663
 664         while(1) {
 665                 if (dwarf_tag(&arg_die) == DW_TAG_formal_parameter) {
 666
 667                         complain(&arg_die, "arg: 0x%02x", dwarf_tag(&arg_die));
 668
 669                         Dwarf_Die type_die;
 670                         if (!get_type_die(&type_die, &arg_die)) {
 671                                 complain(&arg_die, "Couldn't get the argument type die");
 672                                 return false;
 673                         }
 674
 675                         struct arg_type_info* arg_type_info = NULL;
 676                         if (!get_type(&arg_type_info, &type_die, plib, type_dieoffset_hash)) {
 677                                 complain(&arg_die, "Couldn't parse arg type from DWARF data");
 678                                 return false;
 679                         }
 680
 681                         struct param param;
 682                         param_init_type(&param, arg_type_info, 0);
 683                         if (prototype_push_param(proto, &param) <0) {
 684                                 complain(&arg_die, "couldn't add argument to the prototype");
 685                                 return false;
 686                         }
 687
 688 #ifdef DUMP_PROTOTYPES
 689                         fprintf(stderr, "Adding argument:\n");
 690                         dump_ltrace_tree(arg_type_info);
 691 #endif
 692                 }
 693
 694                 NEXT_SIBLING(&arg_die);
 695         }
 696
 697         return true;
 698 }
 699
 700 static bool import_subprogram(struct protolib* plib, struct library* lib,
 701                                                           struct dict* type_dieoffset_hash,
 702                                                           Dwarf_Die* die)
 703 {
 704         // I use the linkage function name if there is one, otherwise the
 705         // plain name
 706         const char* function_name = NULL;
 707         Dwarf_Attribute attr;
 708         if (dwarf_attr(die, DW_AT_linkage_name, &attr) != NULL)
 709                 function_name = dwarf_formstring(&attr);
 710         if (function_name == NULL)
 711                 function_name = dwarf_diename(die);
 712         if (function_name == NULL) {
 713                 complain(die, "Function has no name. Not importing");
 714                 return true;
 715         }
 716
 717         if (!filter_matches_symbol(options.plt_filter,    function_name, lib) &&
 718                 !filter_matches_symbol(options.static_filter, function_name, lib) &&
 719                 !filter_matches_symbol(options.export_filter, function_name, lib)) {
 720                 complain(die, "Prototype not requested by any filter");
 721                 return true;
 722         }
 723
 724         complain(die, "subroutine_type: 0x%02x; function '%s'",
 725                          dwarf_tag(die), function_name);
 726
 727         struct prototype* proto =
 728                 protolib_lookup_prototype(plib, function_name, false);
 729
 730         if (proto != NULL) {
 731                 complain(die, "Prototype already exists. Skipping");
 732                 return true;
 733         }
 734
 735         proto = malloc(sizeof(struct prototype));
 736         if (proto == NULL) {
 737                 complain(die, "couldn't alloc prototype");
 738                 return false;
 739         }
 740         prototype_init(proto);
 741
 742         if (!get_prototype(proto, die, plib, type_dieoffset_hash)) {
 743                 complain(die, "couldn't get prototype");
 744                 return false;
 745         }
 746
 747         protolib_add_prototype(plib, function_name, 0, proto);
 748         return true;
 749 }
 750
 751 static bool process_die_compileunit(struct protolib* plib, struct library* lib,
 752                                                                         struct dict* type_dieoffset_hash,
 753                                                                         Dwarf_Die* parent)
 754 {
 755         Dwarf_Die die;
 756         if (dwarf_child(parent, &die) != 0) {
 757                 // no child nodes, so nothing to do
 758                 return true;
 759         }
 760
 761         while (1) {
 762                 if (dwarf_tag(&die) == DW_TAG_subprogram)
 763                         if(!import_subprogram(plib, lib, type_dieoffset_hash, &die))
 764                                 return false;
 765
 766                 NEXT_SIBLING(&die);
 767         }
 768
 769         return true;
 770 }
 771
 772 static bool import(struct protolib* plib, struct library* lib, Dwfl* dwfl)
 773 {
 774         // A map from DIE addresses (Dwarf_Off) to type structures (struct
 775         // arg_type_info*). This is created and filled in at the start of each
 776         // import, and deleted when the import is complete
 777         struct dict type_dieoffset_hash;
 778
 779         dict_init(&type_dieoffset_hash, sizeof(Dwarf_Off), sizeof(struct arg_type_info*),
 780                           dwarf_die_hash, dwarf_die_eq, NULL);
 781
 782         bool result = true;
 783
 784         Dwarf_Addr bias;
 785     Dwarf_Die* die = NULL;
 786     while ((die = dwfl_nextcu(dwfl, die, &bias)) != NULL) {
 787         if (dwarf_tag(die) == DW_TAG_compile_unit) {
 788             if (!process_die_compileunit(plib, lib, &type_dieoffset_hash, die)) {
 789                 complain(die, "Error reading compile unit");
 790                                 exit(1);
 791
 792                                 result = false;
 793                                 break;
 794             }
 795         } else {
 796             complain(die, "DW_TAG_compile_unit expected");
 797                         exit(1);
 798
 799                         result = false;
 800                         break;
 801         }
 802     }
 803
 804         dict_destroy(&type_dieoffset_hash, NULL, NULL, NULL);
 805         return result;
 806 }
 807
 808 bool import_DWARF_prototypes(struct library* lib)
 809 {
 810         struct protolib*        plib = lib->protolib;
 811         Dwfl*                           dwfl = lib->dwfl;
 812
 813         if (plib == NULL) {
 814                 plib = protolib_cache_default(&g_protocache, lib->soname, 0);
 815                 if (plib == NULL) {
 816                         fprintf(stderr, "Error loading protolib %s: %s.\n",
 817                                         lib->soname, strerror(errno));
 818                 }
 819         }
 820
 821         if (import(plib, lib, dwfl)) {
 822                 lib->protolib = plib;
 823                 return true;
 824         }
 825         return false;
 826 }
 827
 828 /*
 829 - I handle static functions now. Should I? Those do not have DW_AT_external==1
 830
 831 - should process existing prototypes to make sure they match
 832
 833 - what do function pointers look like? I'm doing void*
 834
 835 - unions
 836
 837 - all my *allocs leak
 838
 839
 840 */