linux/tools/perf/util/dwarf-aux.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * dwarf-aux.c : libdw auxiliary interfaces
   4 */
   5
   6#include <errno.h>
   7#include <inttypes.h>
   8#include <stdbool.h>
   9#include <stdlib.h>
  10#include "debug.h"
  11#include "dwarf-aux.h"
  12#include "strbuf.h"
  13#include "string2.h"
  14
  15/**
  16 * cu_find_realpath - Find the realpath of the target file
  17 * @cu_die: A DIE(dwarf information entry) of CU(compilation Unit)
  18 * @fname:  The tail filename of the target file
  19 *
  20 * Find the real(long) path of @fname in @cu_die.
  21 */
  22const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
  23{
  24        Dwarf_Files *files;
  25        size_t nfiles, i;
  26        const char *src = NULL;
  27        int ret;
  28
  29        if (!fname)
  30                return NULL;
  31
  32        ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
  33        if (ret != 0)
  34                return NULL;
  35
  36        for (i = 0; i < nfiles; i++) {
  37                src = dwarf_filesrc(files, i, NULL, NULL);
  38                if (strtailcmp(src, fname) == 0)
  39                        break;
  40        }
  41        if (i == nfiles)
  42                return NULL;
  43        return src;
  44}
  45
  46/**
  47 * cu_get_comp_dir - Get the path of compilation directory
  48 * @cu_die: a CU DIE
  49 *
  50 * Get the path of compilation directory of given @cu_die.
  51 * Since this depends on DW_AT_comp_dir, older gcc will not
  52 * embedded it. In that case, this returns NULL.
  53 */
  54const char *cu_get_comp_dir(Dwarf_Die *cu_die)
  55{
  56        Dwarf_Attribute attr;
  57        if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
  58                return NULL;
  59        return dwarf_formstring(&attr);
  60}
  61
  62/**
  63 * cu_find_lineinfo - Get a line number and file name for given address
  64 * @cu_die: a CU DIE
  65 * @addr: An address
  66 * @fname: a pointer which returns the file name string
  67 * @lineno: a pointer which returns the line number
  68 *
  69 * Find a line number and file name for @addr in @cu_die.
  70 */
  71int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
  72                    const char **fname, int *lineno)
  73{
  74        Dwarf_Line *line;
  75        Dwarf_Addr laddr;
  76
  77        line = dwarf_getsrc_die(cu_die, (Dwarf_Addr)addr);
  78        if (line && dwarf_lineaddr(line, &laddr) == 0 &&
  79            addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) {
  80                *fname = dwarf_linesrc(line, NULL, NULL);
  81                if (!*fname)
  82                        /* line number is useless without filename */
  83                        *lineno = 0;
  84        }
  85
  86        return *lineno ?: -ENOENT;
  87}
  88
  89static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
  90
  91/**
  92 * cu_walk_functions_at - Walk on function DIEs at given address
  93 * @cu_die: A CU DIE
  94 * @addr: An address
  95 * @callback: A callback which called with found DIEs
  96 * @data: A user data
  97 *
  98 * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
  99 * should be subprogram or inlined-subroutines.
 100 */
 101int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
 102                    int (*callback)(Dwarf_Die *, void *), void *data)
 103{
 104        Dwarf_Die die_mem;
 105        Dwarf_Die *sc_die;
 106        int ret = -ENOENT;
 107
 108        /* Inlined function could be recursive. Trace it until fail */
 109        for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
 110             sc_die != NULL;
 111             sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
 112                                     &die_mem)) {
 113                ret = callback(sc_die, data);
 114                if (ret)
 115                        break;
 116        }
 117
 118        return ret;
 119
 120}
 121
 122/**
 123 * die_get_linkage_name - Get the linkage name of the object
 124 * @dw_die: A DIE of the object
 125 *
 126 * Get the linkage name attiribute of given @dw_die.
 127 * For C++ binary, the linkage name will be the mangled symbol.
 128 */
 129const char *die_get_linkage_name(Dwarf_Die *dw_die)
 130{
 131        Dwarf_Attribute attr;
 132
 133        if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
 134                return NULL;
 135        return dwarf_formstring(&attr);
 136}
 137
 138/**
 139 * die_compare_name - Compare diename and tname
 140 * @dw_die: a DIE
 141 * @tname: a string of target name
 142 *
 143 * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
 144 */
 145bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
 146{
 147        const char *name;
 148
 149        name = dwarf_diename(dw_die);
 150        return name ? (strcmp(tname, name) == 0) : false;
 151}
 152
 153/**
 154 * die_match_name - Match diename/linkage name and glob
 155 * @dw_die: a DIE
 156 * @glob: a string of target glob pattern
 157 *
 158 * Glob matching the name of @dw_die and @glob. Return false if matching fail.
 159 * This also match linkage name.
 160 */
 161bool die_match_name(Dwarf_Die *dw_die, const char *glob)
 162{
 163        const char *name;
 164
 165        name = dwarf_diename(dw_die);
 166        if (name && strglobmatch(name, glob))
 167                return true;
 168        /* fall back to check linkage name */
 169        name = die_get_linkage_name(dw_die);
 170        if (name && strglobmatch(name, glob))
 171                return true;
 172
 173        return false;
 174}
 175
 176/**
 177 * die_get_call_lineno - Get callsite line number of inline-function instance
 178 * @in_die: a DIE of an inlined function instance
 179 *
 180 * Get call-site line number of @in_die. This means from where the inline
 181 * function is called.
 182 */
 183int die_get_call_lineno(Dwarf_Die *in_die)
 184{
 185        Dwarf_Attribute attr;
 186        Dwarf_Word ret;
 187
 188        if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
 189                return -ENOENT;
 190
 191        dwarf_formudata(&attr, &ret);
 192        return (int)ret;
 193}
 194
 195/**
 196 * die_get_type - Get type DIE
 197 * @vr_die: a DIE of a variable
 198 * @die_mem: where to store a type DIE
 199 *
 200 * Get a DIE of the type of given variable (@vr_die), and store
 201 * it to die_mem. Return NULL if fails to get a type DIE.
 202 */
 203Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 204{
 205        Dwarf_Attribute attr;
 206
 207        if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
 208            dwarf_formref_die(&attr, die_mem))
 209                return die_mem;
 210        else
 211                return NULL;
 212}
 213
 214/* Get a type die, but skip qualifiers */
 215static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 216{
 217        int tag;
 218
 219        do {
 220                vr_die = die_get_type(vr_die, die_mem);
 221                if (!vr_die)
 222                        break;
 223                tag = dwarf_tag(vr_die);
 224        } while (tag == DW_TAG_const_type ||
 225                 tag == DW_TAG_restrict_type ||
 226                 tag == DW_TAG_volatile_type ||
 227                 tag == DW_TAG_shared_type);
 228
 229        return vr_die;
 230}
 231
 232/**
 233 * die_get_real_type - Get a type die, but skip qualifiers and typedef
 234 * @vr_die: a DIE of a variable
 235 * @die_mem: where to store a type DIE
 236 *
 237 * Get a DIE of the type of given variable (@vr_die), and store
 238 * it to die_mem. Return NULL if fails to get a type DIE.
 239 * If the type is qualifiers (e.g. const) or typedef, this skips it
 240 * and tries to find real type (structure or basic types, e.g. int).
 241 */
 242Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 243{
 244        do {
 245                vr_die = __die_get_real_type(vr_die, die_mem);
 246        } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
 247
 248        return vr_die;
 249}
 250
 251/* Get attribute and translate it as a udata */
 252static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
 253                              Dwarf_Word *result)
 254{
 255        Dwarf_Attribute attr;
 256
 257        if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
 258            dwarf_formudata(&attr, result) != 0)
 259                return -ENOENT;
 260
 261        return 0;
 262}
 263
 264/* Get attribute and translate it as a sdata */
 265static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name,
 266                              Dwarf_Sword *result)
 267{
 268        Dwarf_Attribute attr;
 269
 270        if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
 271            dwarf_formsdata(&attr, result) != 0)
 272                return -ENOENT;
 273
 274        return 0;
 275}
 276
 277/**
 278 * die_is_signed_type - Check whether a type DIE is signed or not
 279 * @tp_die: a DIE of a type
 280 *
 281 * Get the encoding of @tp_die and return true if the encoding
 282 * is signed.
 283 */
 284bool die_is_signed_type(Dwarf_Die *tp_die)
 285{
 286        Dwarf_Word ret;
 287
 288        if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
 289                return false;
 290
 291        return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
 292                ret == DW_ATE_signed_fixed);
 293}
 294
 295/**
 296 * die_is_func_def - Ensure that this DIE is a subprogram and definition
 297 * @dw_die: a DIE
 298 *
 299 * Ensure that this DIE is a subprogram and NOT a declaration. This
 300 * returns true if @dw_die is a function definition.
 301 **/
 302bool die_is_func_def(Dwarf_Die *dw_die)
 303{
 304        Dwarf_Attribute attr;
 305
 306        return (dwarf_tag(dw_die) == DW_TAG_subprogram &&
 307                dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL);
 308}
 309
 310/**
 311 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
 312 * @dw_die: a DIE
 313 *
 314 * Ensure that this DIE is an instance (which has an entry address).
 315 * This returns true if @dw_die is a function instance. If not, you need to
 316 * call die_walk_instances() to find actual instances.
 317 **/
 318bool die_is_func_instance(Dwarf_Die *dw_die)
 319{
 320        Dwarf_Addr tmp;
 321
 322        /* Actually gcc optimizes non-inline as like as inlined */
 323        return !dwarf_func_inline(dw_die) && dwarf_entrypc(dw_die, &tmp) == 0;
 324}
 325/**
 326 * die_get_data_member_location - Get the data-member offset
 327 * @mb_die: a DIE of a member of a data structure
 328 * @offs: The offset of the member in the data structure
 329 *
 330 * Get the offset of @mb_die in the data structure including @mb_die, and
 331 * stores result offset to @offs. If any error occurs this returns errno.
 332 */
 333int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
 334{
 335        Dwarf_Attribute attr;
 336        Dwarf_Op *expr;
 337        size_t nexpr;
 338        int ret;
 339
 340        if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
 341                return -ENOENT;
 342
 343        if (dwarf_formudata(&attr, offs) != 0) {
 344                /* DW_AT_data_member_location should be DW_OP_plus_uconst */
 345                ret = dwarf_getlocation(&attr, &expr, &nexpr);
 346                if (ret < 0 || nexpr == 0)
 347                        return -ENOENT;
 348
 349                if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
 350                        pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
 351                                 expr[0].atom, nexpr);
 352                        return -ENOTSUP;
 353                }
 354                *offs = (Dwarf_Word)expr[0].number;
 355        }
 356        return 0;
 357}
 358
 359/* Get the call file index number in CU DIE */
 360static int die_get_call_fileno(Dwarf_Die *in_die)
 361{
 362        Dwarf_Sword idx;
 363
 364        if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
 365                return (int)idx;
 366        else
 367                return -ENOENT;
 368}
 369
 370/* Get the declared file index number in CU DIE */
 371static int die_get_decl_fileno(Dwarf_Die *pdie)
 372{
 373        Dwarf_Sword idx;
 374
 375        if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
 376                return (int)idx;
 377        else
 378                return -ENOENT;
 379}
 380
 381/**
 382 * die_get_call_file - Get callsite file name of inlined function instance
 383 * @in_die: a DIE of an inlined function instance
 384 *
 385 * Get call-site file name of @in_die. This means from which file the inline
 386 * function is called.
 387 */
 388const char *die_get_call_file(Dwarf_Die *in_die)
 389{
 390        Dwarf_Die cu_die;
 391        Dwarf_Files *files;
 392        int idx;
 393
 394        idx = die_get_call_fileno(in_die);
 395        if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
 396            dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
 397                return NULL;
 398
 399        return dwarf_filesrc(files, idx, NULL, NULL);
 400}
 401
 402
 403/**
 404 * die_find_child - Generic DIE search function in DIE tree
 405 * @rt_die: a root DIE
 406 * @callback: a callback function
 407 * @data: a user data passed to the callback function
 408 * @die_mem: a buffer for result DIE
 409 *
 410 * Trace DIE tree from @rt_die and call @callback for each child DIE.
 411 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
 412 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
 413 * this continues to trace the tree. Optionally, @callback can return
 414 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
 415 * the children and trace only the siblings respectively.
 416 * Returns NULL if @callback can't find any appropriate DIE.
 417 */
 418Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
 419                          int (*callback)(Dwarf_Die *, void *),
 420                          void *data, Dwarf_Die *die_mem)
 421{
 422        Dwarf_Die child_die;
 423        int ret;
 424
 425        ret = dwarf_child(rt_die, die_mem);
 426        if (ret != 0)
 427                return NULL;
 428
 429        do {
 430                ret = callback(die_mem, data);
 431                if (ret == DIE_FIND_CB_END)
 432                        return die_mem;
 433
 434                if ((ret & DIE_FIND_CB_CHILD) &&
 435                    die_find_child(die_mem, callback, data, &child_die)) {
 436                        memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
 437                        return die_mem;
 438                }
 439        } while ((ret & DIE_FIND_CB_SIBLING) &&
 440                 dwarf_siblingof(die_mem, die_mem) == 0);
 441
 442        return NULL;
 443}
 444
 445struct __addr_die_search_param {
 446        Dwarf_Addr      addr;
 447        Dwarf_Die       *die_mem;
 448};
 449
 450static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
 451{
 452        struct __addr_die_search_param *ad = data;
 453        Dwarf_Addr addr = 0;
 454
 455        if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
 456            !dwarf_highpc(fn_die, &addr) &&
 457            addr == ad->addr) {
 458                memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
 459                return DWARF_CB_ABORT;
 460        }
 461        return DWARF_CB_OK;
 462}
 463
 464/**
 465 * die_find_tailfunc - Search for a non-inlined function with tail call at
 466 * given address
 467 * @cu_die: a CU DIE which including @addr
 468 * @addr: target address
 469 * @die_mem: a buffer for result DIE
 470 *
 471 * Search for a non-inlined function DIE with tail call at @addr. Stores the
 472 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 473 */
 474Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
 475                                    Dwarf_Die *die_mem)
 476{
 477        struct __addr_die_search_param ad;
 478        ad.addr = addr;
 479        ad.die_mem = die_mem;
 480        /* dwarf_getscopes can't find subprogram. */
 481        if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
 482                return NULL;
 483        else
 484                return die_mem;
 485}
 486
 487/* die_find callback for non-inlined function search */
 488static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
 489{
 490        struct __addr_die_search_param *ad = data;
 491
 492        /*
 493         * Since a declaration entry doesn't has given pc, this always returns
 494         * function definition entry.
 495         */
 496        if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
 497            dwarf_haspc(fn_die, ad->addr)) {
 498                memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
 499                return DWARF_CB_ABORT;
 500        }
 501        return DWARF_CB_OK;
 502}
 503
 504/**
 505 * die_find_realfunc - Search a non-inlined function at given address
 506 * @cu_die: a CU DIE which including @addr
 507 * @addr: target address
 508 * @die_mem: a buffer for result DIE
 509 *
 510 * Search a non-inlined function DIE which includes @addr. Stores the
 511 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 512 */
 513Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
 514                                    Dwarf_Die *die_mem)
 515{
 516        struct __addr_die_search_param ad;
 517        ad.addr = addr;
 518        ad.die_mem = die_mem;
 519        /* dwarf_getscopes can't find subprogram. */
 520        if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
 521                return NULL;
 522        else
 523                return die_mem;
 524}
 525
 526/* die_find callback for inline function search */
 527static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
 528{
 529        Dwarf_Addr *addr = data;
 530
 531        if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
 532            dwarf_haspc(die_mem, *addr))
 533                return DIE_FIND_CB_END;
 534
 535        return DIE_FIND_CB_CONTINUE;
 536}
 537
 538/**
 539 * die_find_top_inlinefunc - Search the top inlined function at given address
 540 * @sp_die: a subprogram DIE which including @addr
 541 * @addr: target address
 542 * @die_mem: a buffer for result DIE
 543 *
 544 * Search an inlined function DIE which includes @addr. Stores the
 545 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 546 * Even if several inlined functions are expanded recursively, this
 547 * doesn't trace it down, and returns the topmost one.
 548 */
 549Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 550                                   Dwarf_Die *die_mem)
 551{
 552        return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
 553}
 554
 555/**
 556 * die_find_inlinefunc - Search an inlined function at given address
 557 * @sp_die: a subprogram DIE which including @addr
 558 * @addr: target address
 559 * @die_mem: a buffer for result DIE
 560 *
 561 * Search an inlined function DIE which includes @addr. Stores the
 562 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 563 * If several inlined functions are expanded recursively, this trace
 564 * it down and returns deepest one.
 565 */
 566Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 567                               Dwarf_Die *die_mem)
 568{
 569        Dwarf_Die tmp_die;
 570
 571        sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
 572        if (!sp_die)
 573                return NULL;
 574
 575        /* Inlined function could be recursive. Trace it until fail */
 576        while (sp_die) {
 577                memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
 578                sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
 579                                        &tmp_die);
 580        }
 581
 582        return die_mem;
 583}
 584
 585struct __instance_walk_param {
 586        void    *addr;
 587        int     (*callback)(Dwarf_Die *, void *);
 588        void    *data;
 589        int     retval;
 590};
 591
 592static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
 593{
 594        struct __instance_walk_param *iwp = data;
 595        Dwarf_Attribute attr_mem;
 596        Dwarf_Die origin_mem;
 597        Dwarf_Attribute *attr;
 598        Dwarf_Die *origin;
 599        int tmp;
 600
 601        attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
 602        if (attr == NULL)
 603                return DIE_FIND_CB_CONTINUE;
 604
 605        origin = dwarf_formref_die(attr, &origin_mem);
 606        if (origin == NULL || origin->addr != iwp->addr)
 607                return DIE_FIND_CB_CONTINUE;
 608
 609        /* Ignore redundant instances */
 610        if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
 611                dwarf_decl_line(origin, &tmp);
 612                if (die_get_call_lineno(inst) == tmp) {
 613                        tmp = die_get_decl_fileno(origin);
 614                        if (die_get_call_fileno(inst) == tmp)
 615                                return DIE_FIND_CB_CONTINUE;
 616                }
 617        }
 618
 619        iwp->retval = iwp->callback(inst, iwp->data);
 620
 621        return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
 622}
 623
 624/**
 625 * die_walk_instances - Walk on instances of given DIE
 626 * @or_die: an abstract original DIE
 627 * @callback: a callback function which is called with instance DIE
 628 * @data: user data
 629 *
 630 * Walk on the instances of give @in_die. @in_die must be an inlined function
 631 * declartion. This returns the return value of @callback if it returns
 632 * non-zero value, or -ENOENT if there is no instance.
 633 */
 634int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
 635                       void *data)
 636{
 637        Dwarf_Die cu_die;
 638        Dwarf_Die die_mem;
 639        struct __instance_walk_param iwp = {
 640                .addr = or_die->addr,
 641                .callback = callback,
 642                .data = data,
 643                .retval = -ENOENT,
 644        };
 645
 646        if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
 647                return -ENOENT;
 648
 649        die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
 650
 651        return iwp.retval;
 652}
 653
 654/* Line walker internal parameters */
 655struct __line_walk_param {
 656        bool recursive;
 657        line_walk_callback_t callback;
 658        void *data;
 659        int retval;
 660};
 661
 662static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
 663{
 664        struct __line_walk_param *lw = data;
 665        Dwarf_Addr addr = 0;
 666        const char *fname;
 667        int lineno;
 668
 669        if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
 670                fname = die_get_call_file(in_die);
 671                lineno = die_get_call_lineno(in_die);
 672                if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
 673                        lw->retval = lw->callback(fname, lineno, addr, lw->data);
 674                        if (lw->retval != 0)
 675                                return DIE_FIND_CB_END;
 676                }
 677        }
 678        if (!lw->recursive)
 679                /* Don't need to search recursively */
 680                return DIE_FIND_CB_SIBLING;
 681
 682        if (addr) {
 683                fname = dwarf_decl_file(in_die);
 684                if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
 685                        lw->retval = lw->callback(fname, lineno, addr, lw->data);
 686                        if (lw->retval != 0)
 687                                return DIE_FIND_CB_END;
 688                }
 689        }
 690
 691        /* Continue to search nested inlined function call-sites */
 692        return DIE_FIND_CB_CONTINUE;
 693}
 694
 695/* Walk on lines of blocks included in given DIE */
 696static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
 697                                line_walk_callback_t callback, void *data)
 698{
 699        struct __line_walk_param lw = {
 700                .recursive = recursive,
 701                .callback = callback,
 702                .data = data,
 703                .retval = 0,
 704        };
 705        Dwarf_Die die_mem;
 706        Dwarf_Addr addr;
 707        const char *fname;
 708        int lineno;
 709
 710        /* Handle function declaration line */
 711        fname = dwarf_decl_file(sp_die);
 712        if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
 713            dwarf_entrypc(sp_die, &addr) == 0) {
 714                lw.retval = callback(fname, lineno, addr, data);
 715                if (lw.retval != 0)
 716                        goto done;
 717        }
 718        die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
 719done:
 720        return lw.retval;
 721}
 722
 723static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
 724{
 725        struct __line_walk_param *lw = data;
 726
 727        lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
 728        if (lw->retval != 0)
 729                return DWARF_CB_ABORT;
 730
 731        return DWARF_CB_OK;
 732}
 733
 734/**
 735 * die_walk_lines - Walk on lines inside given DIE
 736 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
 737 * @callback: callback routine
 738 * @data: user data
 739 *
 740 * Walk on all lines inside given @rt_die and call @callback on each line.
 741 * If the @rt_die is a function, walk only on the lines inside the function,
 742 * otherwise @rt_die must be a CU DIE.
 743 * Note that this walks not only dwarf line list, but also function entries
 744 * and inline call-site.
 745 */
 746int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 747{
 748        Dwarf_Lines *lines;
 749        Dwarf_Line *line;
 750        Dwarf_Addr addr;
 751        const char *fname, *decf = NULL;
 752        int lineno, ret = 0;
 753        int decl = 0, inl;
 754        Dwarf_Die die_mem, *cu_die;
 755        size_t nlines, i;
 756
 757        /* Get the CU die */
 758        if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
 759                cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
 760                dwarf_decl_line(rt_die, &decl);
 761                decf = dwarf_decl_file(rt_die);
 762        } else
 763                cu_die = rt_die;
 764        if (!cu_die) {
 765                pr_debug2("Failed to get CU from given DIE.\n");
 766                return -EINVAL;
 767        }
 768
 769        /* Get lines list in the CU */
 770        if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
 771                pr_debug2("Failed to get source lines on this CU.\n");
 772                return -ENOENT;
 773        }
 774        pr_debug2("Get %zd lines from this CU\n", nlines);
 775
 776        /* Walk on the lines on lines list */
 777        for (i = 0; i < nlines; i++) {
 778                line = dwarf_onesrcline(lines, i);
 779                if (line == NULL ||
 780                    dwarf_lineno(line, &lineno) != 0 ||
 781                    dwarf_lineaddr(line, &addr) != 0) {
 782                        pr_debug2("Failed to get line info. "
 783                                  "Possible error in debuginfo.\n");
 784                        continue;
 785                }
 786                /* Filter lines based on address */
 787                if (rt_die != cu_die) {
 788                        /*
 789                         * Address filtering
 790                         * The line is included in given function, and
 791                         * no inline block includes it.
 792                         */
 793                        if (!dwarf_haspc(rt_die, addr))
 794                                continue;
 795                        if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
 796                                dwarf_decl_line(&die_mem, &inl);
 797                                if (inl != decl ||
 798                                    decf != dwarf_decl_file(&die_mem))
 799                                        continue;
 800                        }
 801                }
 802                /* Get source line */
 803                fname = dwarf_linesrc(line, NULL, NULL);
 804
 805                ret = callback(fname, lineno, addr, data);
 806                if (ret != 0)
 807                        return ret;
 808        }
 809
 810        /*
 811         * Dwarf lines doesn't include function declarations and inlined
 812         * subroutines. We have to check functions list or given function.
 813         */
 814        if (rt_die != cu_die)
 815                /*
 816                 * Don't need walk functions recursively, because nested
 817                 * inlined functions don't have lines of the specified DIE.
 818                 */
 819                ret = __die_walk_funclines(rt_die, false, callback, data);
 820        else {
 821                struct __line_walk_param param = {
 822                        .callback = callback,
 823                        .data = data,
 824                        .retval = 0,
 825                };
 826                dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
 827                ret = param.retval;
 828        }
 829
 830        return ret;
 831}
 832
 833struct __find_variable_param {
 834        const char *name;
 835        Dwarf_Addr addr;
 836};
 837
 838static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
 839{
 840        struct __find_variable_param *fvp = data;
 841        Dwarf_Attribute attr;
 842        int tag;
 843
 844        tag = dwarf_tag(die_mem);
 845        if ((tag == DW_TAG_formal_parameter ||
 846             tag == DW_TAG_variable) &&
 847            die_compare_name(die_mem, fvp->name) &&
 848        /* Does the DIE have location information or external instance? */
 849            (dwarf_attr(die_mem, DW_AT_external, &attr) ||
 850             dwarf_attr(die_mem, DW_AT_location, &attr)))
 851                return DIE_FIND_CB_END;
 852        if (dwarf_haspc(die_mem, fvp->addr))
 853                return DIE_FIND_CB_CONTINUE;
 854        else
 855                return DIE_FIND_CB_SIBLING;
 856}
 857
 858/**
 859 * die_find_variable_at - Find a given name variable at given address
 860 * @sp_die: a function DIE
 861 * @name: variable name
 862 * @addr: address
 863 * @die_mem: a buffer for result DIE
 864 *
 865 * Find a variable DIE called @name at @addr in @sp_die.
 866 */
 867Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
 868                                Dwarf_Addr addr, Dwarf_Die *die_mem)
 869{
 870        struct __find_variable_param fvp = { .name = name, .addr = addr};
 871
 872        return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
 873                              die_mem);
 874}
 875
 876static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
 877{
 878        const char *name = data;
 879
 880        if (dwarf_tag(die_mem) == DW_TAG_member) {
 881                if (die_compare_name(die_mem, name))
 882                        return DIE_FIND_CB_END;
 883                else if (!dwarf_diename(die_mem)) {     /* Unnamed structure */
 884                        Dwarf_Die type_die, tmp_die;
 885                        if (die_get_type(die_mem, &type_die) &&
 886                            die_find_member(&type_die, name, &tmp_die))
 887                                return DIE_FIND_CB_END;
 888                }
 889        }
 890        return DIE_FIND_CB_SIBLING;
 891}
 892
 893/**
 894 * die_find_member - Find a given name member in a data structure
 895 * @st_die: a data structure type DIE
 896 * @name: member name
 897 * @die_mem: a buffer for result DIE
 898 *
 899 * Find a member DIE called @name in @st_die.
 900 */
 901Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
 902                           Dwarf_Die *die_mem)
 903{
 904        return die_find_child(st_die, __die_find_member_cb, (void *)name,
 905                              die_mem);
 906}
 907
 908/**
 909 * die_get_typename - Get the name of given variable DIE
 910 * @vr_die: a variable DIE
 911 * @buf: a strbuf for result type name
 912 *
 913 * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
 914 * and Return -ENOENT if failed to find type name.
 915 * Note that the result will stores typedef name if possible, and stores
 916 * "*(function_type)" if the type is a function pointer.
 917 */
 918int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
 919{
 920        Dwarf_Die type;
 921        int tag, ret;
 922        const char *tmp = "";
 923
 924        if (__die_get_real_type(vr_die, &type) == NULL)
 925                return -ENOENT;
 926
 927        tag = dwarf_tag(&type);
 928        if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
 929                tmp = "*";
 930        else if (tag == DW_TAG_subroutine_type) {
 931                /* Function pointer */
 932                return strbuf_add(buf, "(function_type)", 15);
 933        } else {
 934                if (!dwarf_diename(&type))
 935                        return -ENOENT;
 936                if (tag == DW_TAG_union_type)
 937                        tmp = "union ";
 938                else if (tag == DW_TAG_structure_type)
 939                        tmp = "struct ";
 940                else if (tag == DW_TAG_enumeration_type)
 941                        tmp = "enum ";
 942                /* Write a base name */
 943                return strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type));
 944        }
 945        ret = die_get_typename(&type, buf);
 946        return ret ? ret : strbuf_addstr(buf, tmp);
 947}
 948
 949/**
 950 * die_get_varname - Get the name and type of given variable DIE
 951 * @vr_die: a variable DIE
 952 * @buf: a strbuf for type and variable name
 953 *
 954 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
 955 */
 956int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
 957{
 958        int ret;
 959
 960        ret = die_get_typename(vr_die, buf);
 961        if (ret < 0) {
 962                pr_debug("Failed to get type, make it unknown.\n");
 963                ret = strbuf_add(buf, " (unknown_type)", 14);
 964        }
 965
 966        return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
 967}
 968
 969#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
 970/**
 971 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
 972 * @sp_die: a subprogram DIE
 973 * @vr_die: a variable DIE
 974 * @buf: a strbuf for variable byte offset range
 975 *
 976 * Get the innermost scope range of @vr_die and stores it in @buf as
 977 * "@<function_name+[NN-NN,NN-NN]>".
 978 */
 979static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
 980                                struct strbuf *buf)
 981{
 982        Dwarf_Die *scopes;
 983        int count;
 984        size_t offset = 0;
 985        Dwarf_Addr base;
 986        Dwarf_Addr start, end;
 987        Dwarf_Addr entry;
 988        int ret;
 989        bool first = true;
 990        const char *name;
 991
 992        ret = dwarf_entrypc(sp_die, &entry);
 993        if (ret)
 994                return ret;
 995
 996        name = dwarf_diename(sp_die);
 997        if (!name)
 998                return -ENOENT;
 999
1000        count = dwarf_getscopes_die(vr_die, &scopes);
1001
1002        /* (*SCOPES)[1] is the DIE for the scope containing that scope */
1003        if (count <= 1) {
1004                ret = -EINVAL;
1005                goto out;
1006        }
1007
1008        while ((offset = dwarf_ranges(&scopes[1], offset, &base,
1009                                        &start, &end)) > 0) {
1010                start -= entry;
1011                end -= entry;
1012
1013                if (first) {
1014                        ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1015                                          name, start, end);
1016                        first = false;
1017                } else {
1018                        ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1019                                          start, end);
1020                }
1021                if (ret < 0)
1022                        goto out;
1023        }
1024
1025        if (!first)
1026                ret = strbuf_add(buf, "]>", 2);
1027
1028out:
1029        free(scopes);
1030        return ret;
1031}
1032
1033/**
1034 * die_get_var_range - Get byte offset range of given variable DIE
1035 * @sp_die: a subprogram DIE
1036 * @vr_die: a variable DIE
1037 * @buf: a strbuf for type and variable name and byte offset range
1038 *
1039 * Get the byte offset range of @vr_die and stores it in @buf as
1040 * "@<function_name+[NN-NN,NN-NN]>".
1041 */
1042int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
1043{
1044        int ret = 0;
1045        Dwarf_Addr base;
1046        Dwarf_Addr start, end;
1047        Dwarf_Addr entry;
1048        Dwarf_Op *op;
1049        size_t nops;
1050        size_t offset = 0;
1051        Dwarf_Attribute attr;
1052        bool first = true;
1053        const char *name;
1054
1055        ret = dwarf_entrypc(sp_die, &entry);
1056        if (ret)
1057                return ret;
1058
1059        name = dwarf_diename(sp_die);
1060        if (!name)
1061                return -ENOENT;
1062
1063        if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
1064                return -EINVAL;
1065
1066        while ((offset = dwarf_getlocations(&attr, offset, &base,
1067                                        &start, &end, &op, &nops)) > 0) {
1068                if (start == 0) {
1069                        /* Single Location Descriptions */
1070                        ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
1071                        goto out;
1072                }
1073
1074                /* Location Lists */
1075                start -= entry;
1076                end -= entry;
1077                if (first) {
1078                        ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1079                                          name, start, end);
1080                        first = false;
1081                } else {
1082                        ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1083                                          start, end);
1084                }
1085                if (ret < 0)
1086                        goto out;
1087        }
1088
1089        if (!first)
1090                ret = strbuf_add(buf, "]>", 2);
1091out:
1092        return ret;
1093}
1094#else
1095int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
1096                      Dwarf_Die *vr_die __maybe_unused,
1097                      struct strbuf *buf __maybe_unused)
1098{
1099        return -ENOTSUP;
1100}
1101#endif
1102
1103/*
1104 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list
1105 * @vr_die: a variable DIE
1106 */
1107static bool die_has_loclist(Dwarf_Die *vr_die)
1108{
1109        Dwarf_Attribute loc;
1110        int tag = dwarf_tag(vr_die);
1111
1112        if (tag != DW_TAG_formal_parameter &&
1113            tag != DW_TAG_variable)
1114                return false;
1115
1116        return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
1117                dwarf_whatform(&loc) == DW_FORM_sec_offset);
1118}
1119
1120/*
1121 * die_is_optimized_target - Check if target program is compiled with
1122 * optimization
1123 * @cu_die: a CU DIE
1124 *
1125 * For any object in given CU whose DW_AT_location is a location list,
1126 * target program is compiled with optimization. This is applicable to
1127 * clang as well.
1128 */
1129bool die_is_optimized_target(Dwarf_Die *cu_die)
1130{
1131        Dwarf_Die tmp_die;
1132
1133        if (die_has_loclist(cu_die))
1134                return true;
1135
1136        if (!dwarf_child(cu_die, &tmp_die) &&
1137            die_is_optimized_target(&tmp_die))
1138                return true;
1139
1140        if (!dwarf_siblingof(cu_die, &tmp_die) &&
1141            die_is_optimized_target(&tmp_die))
1142                return true;
1143
1144        return false;
1145}
1146
1147/*
1148 * die_search_idx - Search index of given line address
1149 * @lines: Line records of single CU
1150 * @nr_lines: Number of @lines
1151 * @addr: address we are looking for
1152 * @idx: index to be set by this function (return value)
1153 *
1154 * Search for @addr by looping over every lines of CU. If address
1155 * matches, set index of that line in @idx. Note that single source
1156 * line can have multiple line records. i.e. single source line can
1157 * have multiple index.
1158 */
1159static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
1160                           Dwarf_Addr addr, unsigned long *idx)
1161{
1162        unsigned long i;
1163        Dwarf_Addr tmp;
1164
1165        for (i = 0; i < nr_lines; i++) {
1166                if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
1167                        return false;
1168
1169                if (tmp == addr) {
1170                        *idx = i;
1171                        return true;
1172                }
1173        }
1174        return false;
1175}
1176
1177/*
1178 * die_get_postprologue_addr - Search next address after function prologue
1179 * @entrypc_idx: entrypc index
1180 * @lines: Line records of single CU
1181 * @nr_lines: Number of @lines
1182 * @hignpc: high PC address of function
1183 * @postprologue_addr: Next address after function prologue (return value)
1184 *
1185 * Look for prologue-end marker. If there is no explicit marker, return
1186 * address of next line record or next source line.
1187 */
1188static bool die_get_postprologue_addr(unsigned long entrypc_idx,
1189                                      Dwarf_Lines *lines,
1190                                      unsigned long nr_lines,
1191                                      Dwarf_Addr highpc,
1192                                      Dwarf_Addr *postprologue_addr)
1193{
1194        unsigned long i;
1195        int entrypc_lno, lno;
1196        Dwarf_Line *line;
1197        Dwarf_Addr addr;
1198        bool p_end;
1199
1200        /* entrypc_lno is actual source line number */
1201        line = dwarf_onesrcline(lines, entrypc_idx);
1202        if (dwarf_lineno(line, &entrypc_lno))
1203                return false;
1204
1205        for (i = entrypc_idx; i < nr_lines; i++) {
1206                line = dwarf_onesrcline(lines, i);
1207
1208                if (dwarf_lineaddr(line, &addr) ||
1209                    dwarf_lineno(line, &lno)    ||
1210                    dwarf_lineprologueend(line, &p_end))
1211                        return false;
1212
1213                /* highpc is exclusive. [entrypc,highpc) */
1214                if (addr >= highpc)
1215                        break;
1216
1217                /* clang supports prologue-end marker */
1218                if (p_end)
1219                        break;
1220
1221                /* Actual next line in source */
1222                if (lno != entrypc_lno)
1223                        break;
1224
1225                /*
1226                 * Single source line can have multiple line records.
1227                 * For Example,
1228                 *     void foo() { printf("hello\n"); }
1229                 * contains two line records. One points to declaration and
1230                 * other points to printf() line. Variable 'lno' won't get
1231                 * incremented in this case but 'i' will.
1232                 */
1233                if (i != entrypc_idx)
1234                        break;
1235        }
1236
1237        dwarf_lineaddr(line, postprologue_addr);
1238        if (*postprologue_addr >= highpc)
1239                dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
1240                               postprologue_addr);
1241
1242        return true;
1243}
1244
1245/*
1246 * die_skip_prologue - Use next address after prologue as probe location
1247 * @sp_die: a subprogram DIE
1248 * @cu_die: a CU DIE
1249 * @entrypc: entrypc of the function
1250 *
1251 * Function prologue prepares stack and registers before executing function
1252 * logic. When target program is compiled without optimization, function
1253 * parameter information is only valid after prologue. When we probe entrypc
1254 * of the function, and try to record function parameter, it contains
1255 * garbage value.
1256 */
1257void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
1258                       Dwarf_Addr *entrypc)
1259{
1260        size_t nr_lines = 0;
1261        unsigned long entrypc_idx = 0;
1262        Dwarf_Lines *lines = NULL;
1263        Dwarf_Addr postprologue_addr;
1264        Dwarf_Addr highpc;
1265
1266        if (dwarf_highpc(sp_die, &highpc))
1267                return;
1268
1269        if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
1270                return;
1271
1272        if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
1273                return;
1274
1275        if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
1276                                       highpc, &postprologue_addr))
1277                return;
1278
1279        *entrypc = postprologue_addr;
1280}
1281