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 // A map from DIE addresses (Dwarf_Off) to type structures (struct
  41 // arg_type_info*). This is created and filled in at the start of each import,
  42 // and deleted when the import is complete
  43 static struct dict type_hash;
  44
  45
  46 static bool get_type(struct arg_type_info** info, Dwarf_Die* type_die);
  47
  48
  49 #if 0
  50 static bool _dump_dwarf_tree(Dwarf_Die* die, int indent)
  51 {
  52     while (1) {
  53         fprintf(stderr, "%*sprocessing unit: 0x%02x/'%s'\n", indent*4, "",
  54                dwarf_tag(die), dwarf_diename(die));
  55
  56         Dwarf_Die child;
  57         if (dwarf_child(die, &child) == 0) {
  58                         if (!_dump_dwarf_tree(&child, indent+1))
  59                                 return false;
  60         }
  61
  62         int res = dwarf_siblingof(die, die);
  63         if (res == 0 ) continue;     // sibling exists
  64         if (res < 0 )  return false; // error
  65         break;                       // no sibling exists
  66     }
  67
  68     return true;
  69 }
  70
  71 static bool dump_dwarf_tree(Dwarf_Die* die)
  72 {
  73     return _dump_dwarf_tree( die, 0 );
  74 }
  75 #endif
  76
  77 #ifdef DUMP_PROTOTYPES
  78 static bool _dump_ltrace_tree(const struct arg_type_info* info, int indent)
  79 {
  80         if (indent > 7) {
  81                 fprintf(stderr, "%*s%p ...\n", indent*4, "", (void*)info);
  82                 return true;
  83         }
  84
  85         if (info == NULL) {
  86                 fprintf(stderr, "%*s%p NULL\n", indent*4, "", (void*)info);
  87                 return true;
  88         }
  89
  90         switch (info->type) {
  91         case ARGTYPE_VOID:
  92                 fprintf(stderr, "%*s%p void\n", indent*4, "", (void*)info);
  93                 break;
  94
  95         case ARGTYPE_INT:
  96         case ARGTYPE_UINT:
  97         case ARGTYPE_LONG:
  98         case ARGTYPE_ULONG:
  99         case ARGTYPE_CHAR:
 100         case ARGTYPE_SHORT:
 101         case ARGTYPE_USHORT:
 102         case ARGTYPE_FLOAT:
 103         case ARGTYPE_DOUBLE:
 104                 fprintf(stderr, "%*s%p base\n", indent*4, "", (void*)info);
 105                 break;
 106
 107         case ARGTYPE_ARRAY:
 108                 fprintf(stderr, "%*s%p array. elements not printed\n", indent*4, "",
 109                                 (void*)info);
 110                 break;
 111
 112         case ARGTYPE_POINTER:
 113                 fprintf(stderr, "%*s%p pointer to...\n", indent*4, "", (void*)info);
 114                 _dump_ltrace_tree( info->u.ptr_info.info, indent+1 );
 115                 break;
 116
 117         case ARGTYPE_STRUCT:
 118                 fprintf(stderr, "%*s%p struct...\n", indent*4, "", (void*)info);
 119                 struct struct_field
 120                 {
 121                         struct arg_type_info *info;
 122                         int own_info;
 123                 }* elements = (struct struct_field*)info->u.entries.data;
 124                 unsigned int i;
 125                 for(i=0; i<info->u.entries.size; i++)
 126                         _dump_ltrace_tree( elements[i].info, indent+1 );
 127                 break;
 128
 129         default:
 130                 fprintf(stderr, "%*s%p unknown type\n", indent*4, "", (void*)info);
 131                 return false;;
 132         }
 133
 134         return true;
 135 }
 136
 137 static bool dump_ltrace_tree(const struct arg_type_info* info)
 138 {
 139         return _dump_ltrace_tree( info, 0 );
 140 }
 141 #endif
 142
 143
 144 // pulls a numerical value out of a particular attribute in a die. Returns true
 145 // if successful. The result is returned in *result. Note that this is cast to
 146 // (uint64_t), regardless of the actual type of the input
 147 static bool get_die_numeric(uint64_t* result,
 148                                                         Dwarf_Die *die, unsigned int attr_name)
 149 {
 150         Dwarf_Attribute attr ;
 151
 152         union {
 153                 Dwarf_Word              udata;
 154                 Dwarf_Sword     sdata;
 155                 Dwarf_Addr              addr;
 156                 bool                    flag;
 157         } u;
 158
 159         if (dwarf_attr(die, attr_name, &attr) == NULL)
 160                 return false;
 161
 162         unsigned int form = dwarf_whatform(&attr);
 163
 164 #define PROCESS_NUMERIC(type)                                           \
 165         if (dwarf_form ## type(&attr, &u.type) != 0)    \
 166                 return false;                                                           \
 167         *result = (uint64_t)u.type;                                             \
 168         return true
 169
 170
 171         switch (form) {
 172         case DW_FORM_addr:
 173                 PROCESS_NUMERIC(addr);
 174
 175         case DW_FORM_data1:
 176         case DW_FORM_data2:
 177         case DW_FORM_data4:
 178         case DW_FORM_data8:
 179         case DW_FORM_udata:
 180                 PROCESS_NUMERIC(udata);
 181
 182         case DW_FORM_sdata:
 183                 PROCESS_NUMERIC(sdata);
 184
 185         case DW_FORM_flag:
 186                 PROCESS_NUMERIC(flag);
 187
 188         default:
 189                 complain(die, "Unknown numeric form %d for attr_name: %d", form, attr_name);
 190                 return false;
 191         }
 192 #undef PROCESS_NUMERIC
 193 }
 194
 195 static bool get_integer_base_type( enum arg_type* type, int byte_size, bool is_signed )
 196 {
 197         switch (byte_size) {
 198         case sizeof(char):
 199                 *type = ARGTYPE_CHAR;
 200                 return true;
 201
 202         case sizeof(short):
 203                 *type = is_signed ? ARGTYPE_SHORT : ARGTYPE_USHORT;
 204                 return true;
 205
 206         case sizeof(int):
 207                 *type = is_signed ? ARGTYPE_INT : ARGTYPE_UINT;
 208                 return true;
 209
 210         case sizeof(long):
 211                 *type = is_signed ? ARGTYPE_LONG : ARGTYPE_ULONG;
 212                 return true;
 213
 214         default:
 215                 return false;
 216         }
 217 }
 218
 219 static enum arg_type get_base_type(Dwarf_Die* die)
 220 {
 221         int64_t encoding;
 222         if( !get_die_numeric((uint64_t*)&encoding, die, DW_AT_encoding) )
 223                 return ARGTYPE_VOID;
 224
 225         if (encoding == DW_ATE_void )
 226                 return ARGTYPE_VOID;
 227
 228         if (encoding == DW_ATE_signed_char || encoding == DW_ATE_unsigned_char )
 229                 return ARGTYPE_CHAR;
 230
 231                 uint64_t byte_size;
 232                 if (!get_die_numeric(&byte_size, die, DW_AT_byte_size))
 233                         return ARGTYPE_VOID;
 234
 235         if (encoding == DW_ATE_signed   ||
 236                 encoding == DW_ATE_unsigned ||
 237                 encoding == DW_ATE_boolean) {
 238
 239                 bool is_signed = (encoding == DW_ATE_signed);
 240
 241                 enum arg_type type;
 242                 if(!get_integer_base_type(&type, (int)byte_size, is_signed)) {
 243                         complain(die, "Unknown integer base type. Using 'void'");
 244                         return ARGTYPE_VOID;
 245                 }
 246                 return type;
 247         }
 248
 249         if (encoding == DW_ATE_float) {
 250                 switch (byte_size) {
 251                 case sizeof(float):
 252                         return ARGTYPE_FLOAT;
 253
 254                 case sizeof(double):
 255                         return ARGTYPE_DOUBLE;
 256
 257                 default:
 258                         // things like long doubles. ltrace has no support yet, so I just
 259                         // say "void"
 260                         return ARGTYPE_VOID;
 261                 }
 262         }
 263
 264 #if 0
 265         if (encoding == DW_ATE_complex_float) {
 266                 switch (byte_size) {
 267                 case 2*sizeof(float):
 268                         return ARGTYPE_FLOAT;
 269
 270                 case 2*sizeof(double):
 271                         return ARGTYPE_DOUBLE;
 272
 273                 default:
 274                         // things like long doubles. ltrace has no support yet, so I just
 275                         // say "void"
 276                         return ARGTYPE_VOID;
 277                 }
 278         }
 279 #endif
 280
 281         // Unknown encoding. I just say void
 282         complain(die, "Unknown base type. Returning 'void'");
 283         return ARGTYPE_VOID;
 284 }
 285
 286 static bool get_type_die(Dwarf_Die* type_die, Dwarf_Die* die)
 287 {
 288         Dwarf_Attribute attr;
 289         return
 290                 dwarf_attr(die, DW_AT_type, &attr) != NULL &&
 291                 dwarf_formref_die(&attr, type_die) != NULL;
 292 }
 293
 294 static size_t dwarf_die_hash(const void* x)
 295 {
 296         return *(const Dwarf_Off*)x;
 297 }
 298 static int dwarf_die_eq(const void* a, const void* b)
 299 {
 300         return *(const Dwarf_Off*)a == *(const Dwarf_Off*)b;
 301 }
 302
 303 static bool get_enum(struct arg_type_info* enum_info, Dwarf_Die* parent)
 304 {
 305         uint64_t byte_size;
 306         if (!get_die_numeric(&byte_size, parent, DW_AT_byte_size)) {
 307                 // No byte size given, assume 'int'
 308                 enum_info->type = ARGTYPE_INT;
 309         } else {
 310                 if(!get_integer_base_type(&enum_info->type, (int)byte_size, true)) {
 311                         complain(parent, "Unknown integer base type. Using 'int'");
 312                         enum_info->type = ARGTYPE_INT;
 313                 }
 314         }
 315
 316         struct enum_lens *lens = calloc(1, sizeof(struct enum_lens));
 317         if (lens == NULL) {
 318                 complain(parent, "alloc error");
 319                 return false;
 320         }
 321         lens_init_enum(lens);
 322         enum_info->lens = &lens->super;
 323
 324         Dwarf_Die die;
 325         if (dwarf_child(parent, &die) != 0) {
 326                 // empty enum. we're done
 327                 return true;
 328         }
 329
 330         while(1) {
 331                 complain(&die, "enum element: 0x%02x/'%s'", dwarf_tag(&die),
 332                                  dwarf_diename(&die));
 333
 334                 if (dwarf_tag(&die) != DW_TAG_enumerator) {
 335                         complain(&die, "Enums can have ONLY DW_TAG_enumerator elements");
 336                         return false;
 337                 }
 338
 339                 if (!dwarf_hasattr(&die, DW_AT_const_value)) {
 340                         complain(&die, "Enums MUST have DW_AT_const_value values");
 341                         return false;
 342                 }
 343
 344                 const char* key = dwarf_diename(&die);
 345                 if (key == NULL) {
 346                         complain(&die, "Enums must have a DW_AT_name key");
 347                         return false;
 348                 }
 349                 const char* dupkey = strdup(key);
 350                 if (dupkey == NULL) {
 351                         complain(&die, "Couldn't duplicate enum key");
 352                         return false;
 353                 }
 354
 355                 struct value* value = calloc( 1, sizeof(struct value));
 356                 if (value == NULL) {
 357                         complain(&die, "Couldn't alloc enum value");
 358                         return false;
 359                 }
 360
 361                 value_init_detached(value, NULL, type_get_simple( enum_info->type ), 0);
 362                 uint64_t enum_value;
 363                 if (!get_die_numeric(&enum_value, &die, DW_AT_const_value)) {
 364                         complain(&die, "Couldn't get enum value");
 365                         return false;
 366                 }
 367
 368                 value_set_word(value, (long)enum_value);
 369
 370                 if (lens_enum_add( lens, dupkey, 0, value, 0 )) {
 371                         complain(&die, "Couldn't add enum element");
 372                         return false;
 373                 }
 374
 375                 int res = dwarf_siblingof(&die, &die);
 376                 if (res == 0) continue;     /* sibling exists    */
 377                 if (res < 0)  return false; /* error             */
 378                 break;                      /* no sibling exists */
 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                 int res = dwarf_siblingof(&die, &die);
 496                 if (res == 0) continue;     /* sibling exists    */
 497                 if (res < 0)  return false; /* error             */
 498                 break;                      /* no sibling exists */
 499         }
 500
 501         return true;
 502 }
 503
 504 // Reads the type in the die into the given structure
 505 // Returns true on sucess
 506 static bool get_type(struct arg_type_info** info, Dwarf_Die* type_die)
 507 {
 508         Dwarf_Off die_offset = dwarf_dieoffset(type_die);
 509         struct arg_type_info** found_type = dict_find(&type_hash, &die_offset );
 510         if (found_type != NULL) {
 511                 *info = *found_type;
 512                 complain(type_die, "Read pre-computed type: %p", *info);
 513                 return true;
 514         }
 515
 516         Dwarf_Die next_die;
 517
 518         switch (dwarf_tag(type_die)) {
 519         case DW_TAG_base_type:
 520                 *info = type_get_simple( get_base_type( type_die ));
 521                 complain(type_die, "Storing base type: %p", *info);
 522                 dict_insert( &type_hash, &die_offset, info );
 523                 return true;
 524
 525         case DW_TAG_subroutine_type:
 526         case DW_TAG_inlined_subroutine:
 527                 // function pointers are stored as void*. If ltrace tries to dereference
 528                 // these, it'll get a segfault
 529                 *info = type_get_simple( ARGTYPE_VOID );
 530                 complain(type_die, "Storing subroutine type: %p", *info);
 531                 dict_insert( &type_hash, &die_offset, info );
 532                 return true;
 533
 534         case DW_TAG_pointer_type:
 535
 536                 if (!get_type_die(&next_die, type_die )) {
 537                         // the pointed-to type isn't defined, so I report a void*
 538                         *info = type_get_simple( ARGTYPE_VOID );
 539                         complain(type_die, "Storing void-pointer type: %p", *info);
 540                         dict_insert( &type_hash, &die_offset, info );
 541                         return true;
 542                 }
 543
 544                 *info = calloc( 1, sizeof(struct arg_type_info));
 545                 if (*info == NULL) {
 546                         complain(type_die, "alloc error");
 547                         return false;
 548                 }
 549                 type_init_pointer(*info, NULL, 0);
 550
 551                 complain(type_die, "Storing pointer type: %p", *info);
 552                 dict_insert( &type_hash, &die_offset, info );
 553                 return get_type( &(*info)->u.ptr_info.info, &next_die );
 554
 555         case DW_TAG_structure_type:
 556                 *info = calloc( 1, sizeof(struct arg_type_info));
 557                 if (*info == NULL) {
 558                         complain(type_die, "alloc error");
 559                         return false;
 560                 }
 561
 562                 complain(type_die, "Storing struct type: %p", *info);
 563                 dict_insert( &type_hash, &die_offset, info );
 564                 return get_structure( *info, type_die );
 565
 566
 567         case DW_TAG_typedef: ;
 568         case DW_TAG_const_type: ;
 569         case DW_TAG_volatile_type: ;
 570                 // Various tags are simply pass-through, so I just keep going
 571                 bool res = true;
 572                 if (get_type_die(&next_die, type_die )) {
 573                         complain(type_die, "Storing const/typedef type: %p", *info);
 574                         res = get_type( info, &next_die );
 575                 } else {
 576                         // no type. Use 'void'. Normally I'd think this is bogus, but stdio
 577                         // typedefs something to void
 578                         *info = type_get_simple( ARGTYPE_VOID );
 579                         complain(type_die, "Storing void type: %p", *info);
 580                 }
 581                 if (res )
 582                         dict_insert( &type_hash, &die_offset, info );
 583                 return res;
 584
 585         case DW_TAG_enumeration_type:
 586                 // We have an enumeration. This has type "int", but has a particular
 587                 // lens to handle the enum
 588                 *info = calloc( 1, sizeof(struct arg_type_info));
 589                 if (*info == NULL) {
 590                         complain(type_die, "alloc error");
 591                         return false;
 592                 }
 593
 594                 complain(type_die, "Storing enum int: %p", *info);
 595                 dict_insert( &type_hash, &die_offset, info );
 596                 return get_enum( *info, type_die );
 597
 598         case DW_TAG_array_type:
 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 array: %p", *info);
 606                 dict_insert( &type_hash, &die_offset, info );
 607                 return get_array( *info, type_die );
 608
 609         case DW_TAG_union_type:
 610                 *info = type_get_simple( ARGTYPE_VOID );
 611                 complain(type_die, "Storing union-as-void type: %p", *info);
 612                 return true;
 613
 614         default:
 615                 complain(type_die, "Unknown type tag 0x%x", dwarf_tag(type_die));
 616                 break;
 617         }
 618
 619         return false;
 620 }
 621
 622 static bool get_prototype(struct prototype* proto, Dwarf_Die* subroutine)
 623 {
 624         // First, look at the return type. This is stored in a DW_AT_type tag in the
 625         // subroutine DIE. If there is no such tag, this function returns void
 626         Dwarf_Die return_type_die;
 627         if (!get_type_die(&return_type_die, subroutine )) {
 628                 proto->return_info = type_get_simple( ARGTYPE_VOID );
 629                 proto->own_return_info = 0;
 630         } else {
 631                 proto->return_info = calloc( 1, sizeof( struct arg_type_info ));
 632                 if (proto->return_info == NULL) {
 633                         complain(subroutine, "Couldn't alloc return type");
 634                         return false;
 635                 }
 636                 proto->own_return_info = 0;
 637
 638                 if (!get_type( &proto->return_info, &return_type_die )) {
 639                         complain(subroutine, "Couldn't get return type");
 640                         return false;
 641                 }
 642         }
 643
 644
 645         // Now look at the arguments
 646         Dwarf_Die arg_die;
 647         if (dwarf_child(subroutine, &arg_die) != 0) {
 648                 // no args. We're done
 649                 return true;
 650         }
 651
 652         while(1) {
 653                 if (dwarf_tag(&arg_die) != DW_TAG_formal_parameter )
 654                         goto next_prototype_argument;
 655
 656                 complain(&arg_die, "arg: 0x%02x", dwarf_tag(&arg_die));
 657
 658                 Dwarf_Die type_die;
 659                 if (!get_type_die(&type_die, &arg_die )) {
 660                         complain(&arg_die, "Couldn't get the argument type die");
 661                         return false;
 662                 }
 663
 664                 struct arg_type_info* arg_type_info = NULL;
 665                 if (!get_type( &arg_type_info, &type_die )) {
 666                         complain(&arg_die, "Couldn't parse arg type from DWARF data");
 667                         return false;
 668                 }
 669
 670                 struct param param;
 671                 param_init_type(&param, arg_type_info, 0);
 672                 if (prototype_push_param(proto, &param) <0) {
 673                         complain(&arg_die, "couldn't add argument to the prototype");
 674                         return false;
 675                 }
 676
 677 #ifdef DUMP_PROTOTYPES
 678                 fprintf(stderr, "Adding argument:\n");
 679                 dump_ltrace_tree(arg_type_info);
 680 #endif
 681
 682         next_prototype_argument: ;
 683                 int res = dwarf_siblingof(&arg_die, &arg_die);
 684                 if (res == 0) continue;     /* sibling exists    */
 685                 if (res < 0)  return false; /* error             */
 686                 break;                      /* no sibling exists */
 687         }
 688
 689         return true;
 690 }
 691
 692 static bool process_die_compileunit(struct protolib* plib, struct library* lib,
 693                                                                         Dwarf_Die* parent)
 694 {
 695         Dwarf_Die die;
 696         if (dwarf_child(parent, &die) != 0) {
 697                 // no child nodes, so nothing to do
 698                 return true;
 699         }
 700
 701         while (1) {
 702                 if (dwarf_tag(&die) == DW_TAG_subprogram) {
 703                         const char* function_name = dwarf_diename(&die);
 704
 705                         complain(&die, "subroutine_type: 0x%02x; function '%s'",
 706                                          dwarf_tag(&die), function_name);
 707
 708                         struct prototype* proto =
 709                                 protolib_lookup_prototype(plib, function_name, true );
 710
 711                         if (proto != NULL) {
 712                                 complain(&die, "Prototype already exists. Skipping");
 713                                 goto next_prototype;
 714                         }
 715
 716                         if (!filter_matches_symbol(options.plt_filter,    function_name, lib) &&
 717                                 !filter_matches_symbol(options.static_filter, function_name, lib) &&
 718                                 !filter_matches_symbol(options.export_filter, function_name, lib)) {
 719                                 complain(&die, "Prototype not requested by any filter");
 720                                 goto next_prototype;
 721                         }
 722
 723                         proto = malloc(sizeof(struct prototype));
 724                         if (proto == NULL) {
 725                                 complain(&die, "couldn't alloc prototype");
 726                                 return false;
 727                         }
 728                         prototype_init( proto );
 729
 730                         if (!get_prototype(proto, &die )) {
 731                                 complain(&die, "couldn't get prototype");
 732                                 return false;
 733                         }
 734
 735                         protolib_add_prototype(plib, function_name, 0, proto);
 736                 }
 737
 738                 next_prototype:;
 739                 int res = dwarf_siblingof(&die, &die);
 740                 if (res == 0) continue;     /* sibling exists    */
 741                 if (res < 0)  return false; /* error             */
 742                 break;                      /* no sibling exists */
 743         }
 744
 745         return true;
 746 }
 747
 748 static bool import(struct protolib* plib, struct library* lib, Dwfl* dwfl)
 749 {
 750         dict_init(&type_hash, sizeof(Dwarf_Off), sizeof(struct arg_type_info*),
 751                           dwarf_die_hash, dwarf_die_eq, NULL );
 752
 753         Dwarf_Addr bias;
 754     Dwarf_Die* die = NULL;
 755     while ((die = dwfl_nextcu(dwfl, die, &bias)) != NULL) {
 756         if (dwarf_tag(die) == DW_TAG_compile_unit) {
 757             if (!process_die_compileunit(plib, lib, die)) {
 758                 complain(die, "Error reading compile unit");
 759                                 exit(1);
 760                                 return false;
 761             }
 762         } else {
 763             complain(die, "DW_TAG_compile_unit expected");
 764                         exit(1);
 765             return false;
 766         }
 767     }
 768
 769         dict_destroy( &type_hash, NULL, NULL, NULL );
 770         return true;
 771 }
 772
 773 bool import_DWARF_prototypes(struct protolib* plib, struct library* lib,
 774                                                          Dwfl *dwfl)
 775 {
 776         if (plib == NULL) {
 777                 plib = protolib_cache_default(&g_protocache, lib->soname, 0);
 778                 if (plib == NULL) {
 779                         fprintf(stderr, "Error loading protolib %s: %s.\n",
 780                                         lib->soname, strerror(errno));
 781                 }
 782         }
 783
 784         return import(plib, lib, dwfl);
 785 }
 786
 787 /*
 788 - I handle static functions now. Should I? Those do not have DW_AT_external==1
 789
 790 - should process existing prototypes to make sure they match
 791
 792 - what do function pointers look like? I'm doing void*
 793
 794 - unions
 795
 796 - all my *allocs leak
 797
 798 - protolib_lookup_prototype should look for imports?
 799
 800 */