1/*
   2 * dwarf-aux.c : libdw auxiliary interfaces
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License as published by
   6 * the Free Software Foundation; either version 2 of the License, or
   7 * (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17 *
  18 */
  19
  20#include <errno.h>
  21#include <inttypes.h>
  22#include <stdbool.h>
  23#include "util.h"
  24#include "debug.h"
  25#include "dwarf-aux.h"
  26#include "string2.h"
  27
  28/**
  29 * cu_find_realpath - Find the realpath of the target file
  30 * @cu_die: A DIE(dwarf information entry) of CU(compilation Unit)
  31 * @fname:  The tail filename of the target file
  32 *
  33 * Find the real(long) path of @fname in @cu_die.
  34 */
  35const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
  36{
  37	Dwarf_Files *files;
  38	size_t nfiles, i;
  39	const char *src = NULL;
  40	int ret;
  41
  42	if (!fname)
  43		return NULL;
  44
  45	ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
  46	if (ret != 0)
  47		return NULL;
  48
  49	for (i = 0; i < nfiles; i++) {
  50		src = dwarf_filesrc(files, i, NULL, NULL);
  51		if (strtailcmp(src, fname) == 0)
  52			break;
  53	}
  54	if (i == nfiles)
  55		return NULL;
  56	return src;
  57}
  58
  59/**
  60 * cu_get_comp_dir - Get the path of compilation directory
  61 * @cu_die: a CU DIE
  62 *
  63 * Get the path of compilation directory of given @cu_die.
  64 * Since this depends on DW_AT_comp_dir, older gcc will not
  65 * embedded it. In that case, this returns NULL.
  66 */
  67const char *cu_get_comp_dir(Dwarf_Die *cu_die)
  68{
  69	Dwarf_Attribute attr;
  70	if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
  71		return NULL;
  72	return dwarf_formstring(&attr);
  73}
  74
  75/**
  76 * cu_find_lineinfo - Get a line number and file name for given address
  77 * @cu_die: a CU DIE
  78 * @addr: An address
  79 * @fname: a pointer which returns the file name string
  80 * @lineno: a pointer which returns the line number
  81 *
  82 * Find a line number and file name for @addr in @cu_die.
  83 */
  84int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
  85		    const char **fname, int *lineno)
  86{
  87	Dwarf_Line *line;
  88	Dwarf_Addr laddr;
  89
  90	line = dwarf_getsrc_die(cu_die, (Dwarf_Addr)addr);
  91	if (line && dwarf_lineaddr(line, &laddr) == 0 &&
  92	    addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) {
  93		*fname = dwarf_linesrc(line, NULL, NULL);
  94		if (!*fname)
  95			/* line number is useless without filename */
  96			*lineno = 0;
  97	}
  98
  99	return *lineno ?: -ENOENT;
 100}
 101
 102static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
 103
 104/**
 105 * cu_walk_functions_at - Walk on function DIEs at given address
 106 * @cu_die: A CU DIE
 107 * @addr: An address
 108 * @callback: A callback which called with found DIEs
 109 * @data: A user data
 110 *
 111 * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
 112 * should be subprogram or inlined-subroutines.
 113 */
 114int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
 115		    int (*callback)(Dwarf_Die *, void *), void *data)
 116{
 117	Dwarf_Die die_mem;
 118	Dwarf_Die *sc_die;
 119	int ret = -ENOENT;
 120
 121	/* Inlined function could be recursive. Trace it until fail */
 122	for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
 123	     sc_die != NULL;
 124	     sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
 125				     &die_mem)) {
 126		ret = callback(sc_die, data);
 127		if (ret)
 128			break;
 129	}
 130
 131	return ret;
 132
 133}
 134
 135/**
 136 * die_get_linkage_name - Get the linkage name of the object
 137 * @dw_die: A DIE of the object
 138 *
 139 * Get the linkage name attiribute of given @dw_die.
 140 * For C++ binary, the linkage name will be the mangled symbol.
 141 */
 142const char *die_get_linkage_name(Dwarf_Die *dw_die)
 143{
 144	Dwarf_Attribute attr;
 145
 146	if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
 147		return NULL;
 148	return dwarf_formstring(&attr);
 149}
 150
 151/**
 152 * die_compare_name - Compare diename and tname
 153 * @dw_die: a DIE
 154 * @tname: a string of target name
 155 *
 156 * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
 157 */
 158bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
 159{
 160	const char *name;
 161
 162	name = dwarf_diename(dw_die);
 163	return name ? (strcmp(tname, name) == 0) : false;
 164}
 165
 166/**
 167 * die_match_name - Match diename/linkage name and glob
 168 * @dw_die: a DIE
 169 * @glob: a string of target glob pattern
 170 *
 171 * Glob matching the name of @dw_die and @glob. Return false if matching fail.
 172 * This also match linkage name.
 173 */
 174bool die_match_name(Dwarf_Die *dw_die, const char *glob)
 175{
 176	const char *name;
 177
 178	name = dwarf_diename(dw_die);
 179	if (name && strglobmatch(name, glob))
 180		return true;
 181	/* fall back to check linkage name */
 182	name = die_get_linkage_name(dw_die);
 183	if (name && strglobmatch(name, glob))
 184		return true;
 185
 186	return false;
 187}
 188
 189/**
 190 * die_get_call_lineno - Get callsite line number of inline-function instance
 191 * @in_die: a DIE of an inlined function instance
 192 *
 193 * Get call-site line number of @in_die. This means from where the inline
 194 * function is called.
 195 */
 196int die_get_call_lineno(Dwarf_Die *in_die)
 197{
 198	Dwarf_Attribute attr;
 199	Dwarf_Word ret;
 200
 201	if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
 202		return -ENOENT;
 203
 204	dwarf_formudata(&attr, &ret);
 205	return (int)ret;
 206}
 207
 208/**
 209 * die_get_type - Get type DIE
 210 * @vr_die: a DIE of a variable
 211 * @die_mem: where to store a type DIE
 212 *
 213 * Get a DIE of the type of given variable (@vr_die), and store
 214 * it to die_mem. Return NULL if fails to get a type DIE.
 215 */
 216Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 217{
 218	Dwarf_Attribute attr;
 219
 220	if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
 221	    dwarf_formref_die(&attr, die_mem))
 222		return die_mem;
 223	else
 224		return NULL;
 225}
 226
 227/* Get a type die, but skip qualifiers */
 228static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 229{
 230	int tag;
 231
 232	do {
 233		vr_die = die_get_type(vr_die, die_mem);
 234		if (!vr_die)
 235			break;
 236		tag = dwarf_tag(vr_die);
 237	} while (tag == DW_TAG_const_type ||
 238		 tag == DW_TAG_restrict_type ||
 239		 tag == DW_TAG_volatile_type ||
 240		 tag == DW_TAG_shared_type);
 241
 242	return vr_die;
 243}
 244
 245/**
 246 * die_get_real_type - Get a type die, but skip qualifiers and typedef
 247 * @vr_die: a DIE of a variable
 248 * @die_mem: where to store a type DIE
 249 *
 250 * Get a DIE of the type of given variable (@vr_die), and store
 251 * it to die_mem. Return NULL if fails to get a type DIE.
 252 * If the type is qualifiers (e.g. const) or typedef, this skips it
 253 * and tries to find real type (structure or basic types, e.g. int).
 254 */
 255Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 256{
 257	do {
 258		vr_die = __die_get_real_type(vr_die, die_mem);
 259	} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
 260
 261	return vr_die;
 262}
 263
 264/* Get attribute and translate it as a udata */
 265static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
 266			      Dwarf_Word *result)
 267{
 268	Dwarf_Attribute attr;
 269
 270	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
 271	    dwarf_formudata(&attr, result) != 0)
 272		return -ENOENT;
 273
 274	return 0;
 275}
 276
 277/* Get attribute and translate it as a sdata */
 278static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name,
 279			      Dwarf_Sword *result)
 280{
 281	Dwarf_Attribute attr;
 282
 283	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
 284	    dwarf_formsdata(&attr, result) != 0)
 285		return -ENOENT;
 286
 287	return 0;
 288}
 289
 290/**
 291 * die_is_signed_type - Check whether a type DIE is signed or not
 292 * @tp_die: a DIE of a type
 293 *
 294 * Get the encoding of @tp_die and return true if the encoding
 295 * is signed.
 296 */
 297bool die_is_signed_type(Dwarf_Die *tp_die)
 298{
 299	Dwarf_Word ret;
 300
 301	if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
 302		return false;
 303
 304	return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
 305		ret == DW_ATE_signed_fixed);
 306}
 307
 308/**
 309 * die_is_func_def - Ensure that this DIE is a subprogram and definition
 310 * @dw_die: a DIE
 311 *
 312 * Ensure that this DIE is a subprogram and NOT a declaration. This
 313 * returns true if @dw_die is a function definition.
 314 **/
 315bool die_is_func_def(Dwarf_Die *dw_die)
 316{
 317	Dwarf_Attribute attr;
 318
 319	return (dwarf_tag(dw_die) == DW_TAG_subprogram &&
 320		dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL);
 321}
 322
 323/**
 324 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
 325 * @dw_die: a DIE
 326 *
 327 * Ensure that this DIE is an instance (which has an entry address).
 328 * This returns true if @dw_die is a function instance. If not, you need to
 329 * call die_walk_instances() to find actual instances.
 330 **/
 331bool die_is_func_instance(Dwarf_Die *dw_die)
 332{
 333	Dwarf_Addr tmp;
 334
 335	/* Actually gcc optimizes non-inline as like as inlined */
 336	return !dwarf_func_inline(dw_die) && dwarf_entrypc(dw_die, &tmp) == 0;
 337}
 338/**
 339 * die_get_data_member_location - Get the data-member offset
 340 * @mb_die: a DIE of a member of a data structure
 341 * @offs: The offset of the member in the data structure
 342 *
 343 * Get the offset of @mb_die in the data structure including @mb_die, and
 344 * stores result offset to @offs. If any error occurs this returns errno.
 345 */
 346int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
 347{
 348	Dwarf_Attribute attr;
 349	Dwarf_Op *expr;
 350	size_t nexpr;
 351	int ret;
 352
 353	if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
 354		return -ENOENT;
 355
 356	if (dwarf_formudata(&attr, offs) != 0) {
 357		/* DW_AT_data_member_location should be DW_OP_plus_uconst */
 358		ret = dwarf_getlocation(&attr, &expr, &nexpr);
 359		if (ret < 0 || nexpr == 0)
 360			return -ENOENT;
 361
 362		if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
 363			pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
 364				 expr[0].atom, nexpr);
 365			return -ENOTSUP;
 366		}
 367		*offs = (Dwarf_Word)expr[0].number;
 368	}
 369	return 0;
 370}
 371
 372/* Get the call file index number in CU DIE */
 373static int die_get_call_fileno(Dwarf_Die *in_die)
 374{
 375	Dwarf_Sword idx;
 376
 377	if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
 378		return (int)idx;
 379	else
 380		return -ENOENT;
 381}
 382
 383/* Get the declared file index number in CU DIE */
 384static int die_get_decl_fileno(Dwarf_Die *pdie)
 385{
 386	Dwarf_Sword idx;
 387
 388	if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
 389		return (int)idx;
 390	else
 391		return -ENOENT;
 392}
 393
 394/**
 395 * die_get_call_file - Get callsite file name of inlined function instance
 396 * @in_die: a DIE of an inlined function instance
 397 *
 398 * Get call-site file name of @in_die. This means from which file the inline
 399 * function is called.
 400 */
 401const char *die_get_call_file(Dwarf_Die *in_die)
 402{
 403	Dwarf_Die cu_die;
 404	Dwarf_Files *files;
 405	int idx;
 406
 407	idx = die_get_call_fileno(in_die);
 408	if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
 409	    dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
 410		return NULL;
 411
 412	return dwarf_filesrc(files, idx, NULL, NULL);
 413}
 414
 415
 416/**
 417 * die_find_child - Generic DIE search function in DIE tree
 418 * @rt_die: a root DIE
 419 * @callback: a callback function
 420 * @data: a user data passed to the callback function
 421 * @die_mem: a buffer for result DIE
 422 *
 423 * Trace DIE tree from @rt_die and call @callback for each child DIE.
 424 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
 425 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
 426 * this continues to trace the tree. Optionally, @callback can return
 427 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
 428 * the children and trace only the siblings respectively.
 429 * Returns NULL if @callback can't find any appropriate DIE.
 430 */
 431Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
 432			  int (*callback)(Dwarf_Die *, void *),
 433			  void *data, Dwarf_Die *die_mem)
 434{
 435	Dwarf_Die child_die;
 436	int ret;
 437
 438	ret = dwarf_child(rt_die, die_mem);
 439	if (ret != 0)
 440		return NULL;
 441
 442	do {
 443		ret = callback(die_mem, data);
 444		if (ret == DIE_FIND_CB_END)
 445			return die_mem;
 446
 447		if ((ret & DIE_FIND_CB_CHILD) &&
 448		    die_find_child(die_mem, callback, data, &child_die)) {
 449			memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
 450			return die_mem;
 451		}
 452	} while ((ret & DIE_FIND_CB_SIBLING) &&
 453		 dwarf_siblingof(die_mem, die_mem) == 0);
 454
 455	return NULL;
 456}
 457
 458struct __addr_die_search_param {
 459	Dwarf_Addr	addr;
 460	Dwarf_Die	*die_mem;
 461};
 462
 463static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
 464{
 465	struct __addr_die_search_param *ad = data;
 466	Dwarf_Addr addr = 0;
 467
 468	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
 469	    !dwarf_highpc(fn_die, &addr) &&
 470	    addr == ad->addr) {
 471		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
 472		return DWARF_CB_ABORT;
 473	}
 474	return DWARF_CB_OK;
 475}
 476
 477/**
 478 * die_find_tailfunc - Search for a non-inlined function with tail call at
 479 * given address
 480 * @cu_die: a CU DIE which including @addr
 481 * @addr: target address
 482 * @die_mem: a buffer for result DIE
 483 *
 484 * Search for a non-inlined function DIE with tail call at @addr. Stores the
 485 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 486 */
 487Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
 488				    Dwarf_Die *die_mem)
 489{
 490	struct __addr_die_search_param ad;
 491	ad.addr = addr;
 492	ad.die_mem = die_mem;
 493	/* dwarf_getscopes can't find subprogram. */
 494	if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
 495		return NULL;
 496	else
 497		return die_mem;
 498}
 499
 500/* die_find callback for non-inlined function search */
 501static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
 502{
 503	struct __addr_die_search_param *ad = data;
 504
 505	/*
 506	 * Since a declaration entry doesn't has given pc, this always returns
 507	 * function definition entry.
 508	 */
 509	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
 510	    dwarf_haspc(fn_die, ad->addr)) {
 511		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
 512		return DWARF_CB_ABORT;
 513	}
 514	return DWARF_CB_OK;
 515}
 516
 517/**
 518 * die_find_realfunc - Search a non-inlined function at given address
 519 * @cu_die: a CU DIE which including @addr
 520 * @addr: target address
 521 * @die_mem: a buffer for result DIE
 522 *
 523 * Search a non-inlined function DIE which includes @addr. Stores the
 524 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 525 */
 526Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
 527				    Dwarf_Die *die_mem)
 528{
 529	struct __addr_die_search_param ad;
 530	ad.addr = addr;
 531	ad.die_mem = die_mem;
 532	/* dwarf_getscopes can't find subprogram. */
 533	if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
 534		return NULL;
 535	else
 536		return die_mem;
 537}
 538
 539/* die_find callback for inline function search */
 540static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
 541{
 542	Dwarf_Addr *addr = data;
 543
 544	if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
 545	    dwarf_haspc(die_mem, *addr))
 546		return DIE_FIND_CB_END;
 547
 548	return DIE_FIND_CB_CONTINUE;
 549}
 550
 551/**
 552 * die_find_top_inlinefunc - Search the top inlined function at given address
 553 * @sp_die: a subprogram DIE which including @addr
 554 * @addr: target address
 555 * @die_mem: a buffer for result DIE
 556 *
 557 * Search an inlined function DIE which includes @addr. Stores the
 558 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 559 * Even if several inlined functions are expanded recursively, this
 560 * doesn't trace it down, and returns the topmost one.
 561 */
 562Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 563				   Dwarf_Die *die_mem)
 564{
 565	return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
 566}
 567
 568/**
 569 * die_find_inlinefunc - Search an inlined function at given address
 570 * @sp_die: a subprogram DIE which including @addr
 571 * @addr: target address
 572 * @die_mem: a buffer for result DIE
 573 *
 574 * Search an inlined function DIE which includes @addr. Stores the
 575 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 576 * If several inlined functions are expanded recursively, this trace
 577 * it down and returns deepest one.
 578 */
 579Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 580			       Dwarf_Die *die_mem)
 581{
 582	Dwarf_Die tmp_die;
 583
 584	sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
 585	if (!sp_die)
 586		return NULL;
 587
 588	/* Inlined function could be recursive. Trace it until fail */
 589	while (sp_die) {
 590		memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
 591		sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
 592					&tmp_die);
 593	}
 594
 595	return die_mem;
 596}
 597
 598struct __instance_walk_param {
 599	void    *addr;
 600	int	(*callback)(Dwarf_Die *, void *);
 601	void    *data;
 602	int	retval;
 603};
 604
 605static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
 606{
 607	struct __instance_walk_param *iwp = data;
 608	Dwarf_Attribute attr_mem;
 609	Dwarf_Die origin_mem;
 610	Dwarf_Attribute *attr;
 611	Dwarf_Die *origin;
 612	int tmp;
 613
 614	attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
 615	if (attr == NULL)
 616		return DIE_FIND_CB_CONTINUE;
 617
 618	origin = dwarf_formref_die(attr, &origin_mem);
 619	if (origin == NULL || origin->addr != iwp->addr)
 620		return DIE_FIND_CB_CONTINUE;
 621
 622	/* Ignore redundant instances */
 623	if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
 624		dwarf_decl_line(origin, &tmp);
 625		if (die_get_call_lineno(inst) == tmp) {
 626			tmp = die_get_decl_fileno(origin);
 627			if (die_get_call_fileno(inst) == tmp)
 628				return DIE_FIND_CB_CONTINUE;
 629		}
 630	}
 631
 632	iwp->retval = iwp->callback(inst, iwp->data);
 633
 634	return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
 635}
 636
 637/**
 638 * die_walk_instances - Walk on instances of given DIE
 639 * @or_die: an abstract original DIE
 640 * @callback: a callback function which is called with instance DIE
 641 * @data: user data
 642 *
 643 * Walk on the instances of give @in_die. @in_die must be an inlined function
 644 * declartion. This returns the return value of @callback if it returns
 645 * non-zero value, or -ENOENT if there is no instance.
 646 */
 647int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
 648		       void *data)
 649{
 650	Dwarf_Die cu_die;
 651	Dwarf_Die die_mem;
 652	struct __instance_walk_param iwp = {
 653		.addr = or_die->addr,
 654		.callback = callback,
 655		.data = data,
 656		.retval = -ENOENT,
 657	};
 658
 659	if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
 660		return -ENOENT;
 661
 662	die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
 663
 664	return iwp.retval;
 665}
 666
 667/* Line walker internal parameters */
 668struct __line_walk_param {
 669	bool recursive;
 670	line_walk_callback_t callback;
 671	void *data;
 672	int retval;
 673};
 674
 675static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
 676{
 677	struct __line_walk_param *lw = data;
 678	Dwarf_Addr addr = 0;
 679	const char *fname;
 680	int lineno;
 681
 682	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
 683		fname = die_get_call_file(in_die);
 684		lineno = die_get_call_lineno(in_die);
 685		if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
 686			lw->retval = lw->callback(fname, lineno, addr, lw->data);
 687			if (lw->retval != 0)
 688				return DIE_FIND_CB_END;
 689		}
 690	}
 691	if (!lw->recursive)
 692		/* Don't need to search recursively */
 693		return DIE_FIND_CB_SIBLING;
 694
 695	if (addr) {
 696		fname = dwarf_decl_file(in_die);
 697		if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
 698			lw->retval = lw->callback(fname, lineno, addr, lw->data);
 699			if (lw->retval != 0)
 700				return DIE_FIND_CB_END;
 701		}
 702	}
 703
 704	/* Continue to search nested inlined function call-sites */
 705	return DIE_FIND_CB_CONTINUE;
 706}
 707
 708/* Walk on lines of blocks included in given DIE */
 709static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
 710				line_walk_callback_t callback, void *data)
 711{
 712	struct __line_walk_param lw = {
 713		.recursive = recursive,
 714		.callback = callback,
 715		.data = data,
 716		.retval = 0,
 717	};
 718	Dwarf_Die die_mem;
 719	Dwarf_Addr addr;
 720	const char *fname;
 721	int lineno;
 722
 723	/* Handle function declaration line */
 724	fname = dwarf_decl_file(sp_die);
 725	if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
 726	    dwarf_entrypc(sp_die, &addr) == 0) {
 727		lw.retval = callback(fname, lineno, addr, data);
 728		if (lw.retval != 0)
 729			goto done;
 730	}
 731	die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
 732done:
 733	return lw.retval;
 734}
 735
 736static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
 737{
 738	struct __line_walk_param *lw = data;
 739
 740	lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
 741	if (lw->retval != 0)
 742		return DWARF_CB_ABORT;
 743
 744	return DWARF_CB_OK;
 745}
 746
 747/**
 748 * die_walk_lines - Walk on lines inside given DIE
 749 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
 750 * @callback: callback routine
 751 * @data: user data
 752 *
 753 * Walk on all lines inside given @rt_die and call @callback on each line.
 754 * If the @rt_die is a function, walk only on the lines inside the function,
 755 * otherwise @rt_die must be a CU DIE.
 756 * Note that this walks not only dwarf line list, but also function entries
 757 * and inline call-site.
 758 */
 759int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 760{
 761	Dwarf_Lines *lines;
 762	Dwarf_Line *line;
 763	Dwarf_Addr addr;
 764	const char *fname, *decf = NULL;
 765	int lineno, ret = 0;
 766	int decl = 0, inl;
 767	Dwarf_Die die_mem, *cu_die;
 768	size_t nlines, i;
 769
 770	/* Get the CU die */
 771	if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
 772		cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
 773		dwarf_decl_line(rt_die, &decl);
 774		decf = dwarf_decl_file(rt_die);
 775	} else
 776		cu_die = rt_die;
 777	if (!cu_die) {
 778		pr_debug2("Failed to get CU from given DIE.\n");
 779		return -EINVAL;
 780	}
 781
 782	/* Get lines list in the CU */
 783	if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
 784		pr_debug2("Failed to get source lines on this CU.\n");
 785		return -ENOENT;
 786	}
 787	pr_debug2("Get %zd lines from this CU\n", nlines);
 788
 789	/* Walk on the lines on lines list */
 790	for (i = 0; i < nlines; i++) {
 791		line = dwarf_onesrcline(lines, i);
 792		if (line == NULL ||
 793		    dwarf_lineno(line, &lineno) != 0 ||
 794		    dwarf_lineaddr(line, &addr) != 0) {
 795			pr_debug2("Failed to get line info. "
 796				  "Possible error in debuginfo.\n");
 797			continue;
 798		}
 799		/* Filter lines based on address */
 800		if (rt_die != cu_die) {
 801			/*
 802			 * Address filtering
 803			 * The line is included in given function, and
 804			 * no inline block includes it.
 805			 */
 806			if (!dwarf_haspc(rt_die, addr))
 
 807				continue;
 808			if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
 809				dwarf_decl_line(&die_mem, &inl);
 810				if (inl != decl ||
 811				    decf != dwarf_decl_file(&die_mem))
 812					continue;
 813			}
 814		}
 815		/* Get source line */
 816		fname = dwarf_linesrc(line, NULL, NULL);
 817
 818		ret = callback(fname, lineno, addr, data);
 819		if (ret != 0)
 820			return ret;
 821	}
 822
 823	/*
 824	 * Dwarf lines doesn't include function declarations and inlined
 825	 * subroutines. We have to check functions list or given function.
 826	 */
 827	if (rt_die != cu_die)
 828		/*
 829		 * Don't need walk functions recursively, because nested
 830		 * inlined functions don't have lines of the specified DIE.
 831		 */
 832		ret = __die_walk_funclines(rt_die, false, callback, data);
 833	else {
 834		struct __line_walk_param param = {
 835			.callback = callback,
 836			.data = data,
 837			.retval = 0,
 838		};
 839		dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
 840		ret = param.retval;
 841	}
 842
 843	return ret;
 844}
 845
 846struct __find_variable_param {
 847	const char *name;
 848	Dwarf_Addr addr;
 849};
 850
 851static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
 852{
 853	struct __find_variable_param *fvp = data;
 854	Dwarf_Attribute attr;
 855	int tag;
 856
 857	tag = dwarf_tag(die_mem);
 858	if ((tag == DW_TAG_formal_parameter ||
 859	     tag == DW_TAG_variable) &&
 860	    die_compare_name(die_mem, fvp->name) &&
 861	/* Does the DIE have location information or external instance? */
 862	    (dwarf_attr(die_mem, DW_AT_external, &attr) ||
 863	     dwarf_attr(die_mem, DW_AT_location, &attr)))
 864		return DIE_FIND_CB_END;
 
 865	if (dwarf_haspc(die_mem, fvp->addr))
 866		return DIE_FIND_CB_CONTINUE;
 867	else
 868		return DIE_FIND_CB_SIBLING;
 869}
 870
 871/**
 872 * die_find_variable_at - Find a given name variable at given address
 873 * @sp_die: a function DIE
 874 * @name: variable name
 875 * @addr: address
 876 * @die_mem: a buffer for result DIE
 877 *
 878 * Find a variable DIE called @name at @addr in @sp_die.
 879 */
 880Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
 881				Dwarf_Addr addr, Dwarf_Die *die_mem)
 882{
 883	struct __find_variable_param fvp = { .name = name, .addr = addr};
 884
 885	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
 886			      die_mem);
 887}
 888
 889static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
 890{
 891	const char *name = data;
 892
 893	if (dwarf_tag(die_mem) == DW_TAG_member) {
 894		if (die_compare_name(die_mem, name))
 895			return DIE_FIND_CB_END;
 896		else if (!dwarf_diename(die_mem)) {	/* Unnamed structure */
 897			Dwarf_Die type_die, tmp_die;
 898			if (die_get_type(die_mem, &type_die) &&
 899			    die_find_member(&type_die, name, &tmp_die))
 900				return DIE_FIND_CB_END;
 901		}
 902	}
 903	return DIE_FIND_CB_SIBLING;
 904}
 905
 906/**
 907 * die_find_member - Find a given name member in a data structure
 908 * @st_die: a data structure type DIE
 909 * @name: member name
 910 * @die_mem: a buffer for result DIE
 911 *
 912 * Find a member DIE called @name in @st_die.
 913 */
 914Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
 915			   Dwarf_Die *die_mem)
 916{
 917	return die_find_child(st_die, __die_find_member_cb, (void *)name,
 918			      die_mem);
 919}
 920
 921/**
 922 * die_get_typename - Get the name of given variable DIE
 923 * @vr_die: a variable DIE
 924 * @buf: a strbuf for result type name
 
 925 *
 926 * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
 927 * and Return -ENOENT if failed to find type name.
 
 928 * Note that the result will stores typedef name if possible, and stores
 929 * "*(function_type)" if the type is a function pointer.
 930 */
 931int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
 932{
 933	Dwarf_Die type;
 934	int tag, ret;
 935	const char *tmp = "";
 936
 937	if (__die_get_real_type(vr_die, &type) == NULL)
 938		return -ENOENT;
 939
 940	tag = dwarf_tag(&type);
 941	if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
 942		tmp = "*";
 943	else if (tag == DW_TAG_subroutine_type) {
 944		/* Function pointer */
 945		return strbuf_add(buf, "(function_type)", 15);
 
 946	} else {
 947		if (!dwarf_diename(&type))
 948			return -ENOENT;
 949		if (tag == DW_TAG_union_type)
 950			tmp = "union ";
 951		else if (tag == DW_TAG_structure_type)
 952			tmp = "struct ";
 953		else if (tag == DW_TAG_enumeration_type)
 954			tmp = "enum ";
 955		/* Write a base name */
 956		return strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type));
 
 
 
 
 
 
 957	}
 958	ret = die_get_typename(&type, buf);
 959	return ret ? ret : strbuf_addstr(buf, tmp);
 960}
 961
 962/**
 963 * die_get_varname - Get the name and type of given variable DIE
 964 * @vr_die: a variable DIE
 965 * @buf: a strbuf for type and variable name
 
 966 *
 967 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
 968 */
 969int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
 970{
 971	int ret;
 972
 973	ret = die_get_typename(vr_die, buf);
 974	if (ret < 0) {
 975		pr_debug("Failed to get type, make it unknown.\n");
 976		ret = strbuf_add(buf, " (unknown_type)", 14);
 977	}
 978
 979	return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
 980}
 981
 982#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
 983/**
 984 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
 985 * @sp_die: a subprogram DIE
 986 * @vr_die: a variable DIE
 987 * @buf: a strbuf for variable byte offset range
 988 *
 989 * Get the innermost scope range of @vr_die and stores it in @buf as
 990 * "@<function_name+[NN-NN,NN-NN]>".
 991 */
 992static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
 993				struct strbuf *buf)
 994{
 995	Dwarf_Die *scopes;
 996	int count;
 997	size_t offset = 0;
 998	Dwarf_Addr base;
 999	Dwarf_Addr start, end;
1000	Dwarf_Addr entry;
1001	int ret;
1002	bool first = true;
1003	const char *name;
1004
1005	ret = dwarf_entrypc(sp_die, &entry);
1006	if (ret)
1007		return ret;
1008
1009	name = dwarf_diename(sp_die);
1010	if (!name)
1011		return -ENOENT;
1012
1013	count = dwarf_getscopes_die(vr_die, &scopes);
1014
1015	/* (*SCOPES)[1] is the DIE for the scope containing that scope */
1016	if (count <= 1) {
1017		ret = -EINVAL;
1018		goto out;
1019	}
1020
1021	while ((offset = dwarf_ranges(&scopes[1], offset, &base,
1022					&start, &end)) > 0) {
1023		start -= entry;
1024		end -= entry;
1025
1026		if (first) {
1027			ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1028					  name, start, end);
1029			first = false;
1030		} else {
1031			ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1032					  start, end);
1033		}
1034		if (ret < 0)
1035			goto out;
1036	}
1037
1038	if (!first)
1039		ret = strbuf_add(buf, "]>", 2);
1040
1041out:
1042	free(scopes);
1043	return ret;
1044}
1045
1046/**
1047 * die_get_var_range - Get byte offset range of given variable DIE
1048 * @sp_die: a subprogram DIE
1049 * @vr_die: a variable DIE
1050 * @buf: a strbuf for type and variable name and byte offset range
1051 *
1052 * Get the byte offset range of @vr_die and stores it in @buf as
1053 * "@<function_name+[NN-NN,NN-NN]>".
1054 */
1055int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
1056{
1057	int ret = 0;
1058	Dwarf_Addr base;
1059	Dwarf_Addr start, end;
1060	Dwarf_Addr entry;
1061	Dwarf_Op *op;
1062	size_t nops;
1063	size_t offset = 0;
1064	Dwarf_Attribute attr;
1065	bool first = true;
1066	const char *name;
1067
1068	ret = dwarf_entrypc(sp_die, &entry);
1069	if (ret)
1070		return ret;
1071
1072	name = dwarf_diename(sp_die);
1073	if (!name)
1074		return -ENOENT;
1075
1076	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
1077		return -EINVAL;
1078
1079	while ((offset = dwarf_getlocations(&attr, offset, &base,
1080					&start, &end, &op, &nops)) > 0) {
1081		if (start == 0) {
1082			/* Single Location Descriptions */
1083			ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
1084			goto out;
1085		}
1086
1087		/* Location Lists */
1088		start -= entry;
1089		end -= entry;
1090		if (first) {
1091			ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1092					  name, start, end);
1093			first = false;
1094		} else {
1095			ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1096					  start, end);
1097		}
1098		if (ret < 0)
1099			goto out;
1100	}
1101
1102	if (!first)
1103		ret = strbuf_add(buf, "]>", 2);
1104out:
1105	return ret;
1106}
1107#else
1108int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
1109		      Dwarf_Die *vr_die __maybe_unused,
1110		      struct strbuf *buf __maybe_unused)
1111{
1112	return -ENOTSUP;
1113}
1114#endif
1115
1116/*
1117 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list
1118 * @vr_die: a variable DIE
1119 */
1120static bool die_has_loclist(Dwarf_Die *vr_die)
1121{
1122	Dwarf_Attribute loc;
1123	int tag = dwarf_tag(vr_die);
1124
1125	if (tag != DW_TAG_formal_parameter &&
1126	    tag != DW_TAG_variable)
1127		return false;
1128
1129	return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
1130		dwarf_whatform(&loc) == DW_FORM_sec_offset);
1131}
1132
1133/*
1134 * die_is_optimized_target - Check if target program is compiled with
1135 * optimization
1136 * @cu_die: a CU DIE
1137 *
1138 * For any object in given CU whose DW_AT_location is a location list,
1139 * target program is compiled with optimization. This is applicable to
1140 * clang as well.
1141 */
1142bool die_is_optimized_target(Dwarf_Die *cu_die)
1143{
1144	Dwarf_Die tmp_die;
1145
1146	if (die_has_loclist(cu_die))
1147		return true;
1148
1149	if (!dwarf_child(cu_die, &tmp_die) &&
1150	    die_is_optimized_target(&tmp_die))
1151		return true;
1152
1153	if (!dwarf_siblingof(cu_die, &tmp_die) &&
1154	    die_is_optimized_target(&tmp_die))
1155		return true;
1156
1157	return false;
1158}
1159
1160/*
1161 * die_search_idx - Search index of given line address
1162 * @lines: Line records of single CU
1163 * @nr_lines: Number of @lines
1164 * @addr: address we are looking for
1165 * @idx: index to be set by this function (return value)
1166 *
1167 * Search for @addr by looping over every lines of CU. If address
1168 * matches, set index of that line in @idx. Note that single source
1169 * line can have multiple line records. i.e. single source line can
1170 * have multiple index.
1171 */
1172static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
1173			   Dwarf_Addr addr, unsigned long *idx)
1174{
1175	unsigned long i;
1176	Dwarf_Addr tmp;
1177
1178	for (i = 0; i < nr_lines; i++) {
1179		if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
1180			return false;
1181
1182		if (tmp == addr) {
1183			*idx = i;
1184			return true;
1185		}
1186	}
1187	return false;
1188}
1189
1190/*
1191 * die_get_postprologue_addr - Search next address after function prologue
1192 * @entrypc_idx: entrypc index
1193 * @lines: Line records of single CU
1194 * @nr_lines: Number of @lines
1195 * @hignpc: high PC address of function
1196 * @postprologue_addr: Next address after function prologue (return value)
1197 *
1198 * Look for prologue-end marker. If there is no explicit marker, return
1199 * address of next line record or next source line.
1200 */
1201static bool die_get_postprologue_addr(unsigned long entrypc_idx,
1202				      Dwarf_Lines *lines,
1203				      unsigned long nr_lines,
1204				      Dwarf_Addr highpc,
1205				      Dwarf_Addr *postprologue_addr)
1206{
1207	unsigned long i;
1208	int entrypc_lno, lno;
1209	Dwarf_Line *line;
1210	Dwarf_Addr addr;
1211	bool p_end;
1212
1213	/* entrypc_lno is actual source line number */
1214	line = dwarf_onesrcline(lines, entrypc_idx);
1215	if (dwarf_lineno(line, &entrypc_lno))
1216		return false;
1217
1218	for (i = entrypc_idx; i < nr_lines; i++) {
1219		line = dwarf_onesrcline(lines, i);
1220
1221		if (dwarf_lineaddr(line, &addr) ||
1222		    dwarf_lineno(line, &lno)    ||
1223		    dwarf_lineprologueend(line, &p_end))
1224			return false;
1225
1226		/* highpc is exclusive. [entrypc,highpc) */
1227		if (addr >= highpc)
1228			break;
1229
1230		/* clang supports prologue-end marker */
1231		if (p_end)
1232			break;
1233
1234		/* Actual next line in source */
1235		if (lno != entrypc_lno)
1236			break;
1237
1238		/*
1239		 * Single source line can have multiple line records.
1240		 * For Example,
1241		 *     void foo() { printf("hello\n"); }
1242		 * contains two line records. One points to declaration and
1243		 * other points to printf() line. Variable 'lno' won't get
1244		 * incremented in this case but 'i' will.
1245		 */
1246		if (i != entrypc_idx)
1247			break;
1248	}
1249
1250	dwarf_lineaddr(line, postprologue_addr);
1251	if (*postprologue_addr >= highpc)
1252		dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
1253			       postprologue_addr);
1254
1255	return true;
1256}
1257
1258/*
1259 * die_skip_prologue - Use next address after prologue as probe location
1260 * @sp_die: a subprogram DIE
1261 * @cu_die: a CU DIE
1262 * @entrypc: entrypc of the function
1263 *
1264 * Function prologue prepares stack and registers before executing function
1265 * logic. When target program is compiled without optimization, function
1266 * parameter information is only valid after prologue. When we probe entrypc
1267 * of the function, and try to record function parameter, it contains
1268 * garbage value.
1269 */
1270void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
1271		       Dwarf_Addr *entrypc)
1272{
1273	size_t nr_lines = 0;
1274	unsigned long entrypc_idx = 0;
1275	Dwarf_Lines *lines = NULL;
1276	Dwarf_Addr postprologue_addr;
1277	Dwarf_Addr highpc;
1278
1279	if (dwarf_highpc(sp_die, &highpc))
1280		return;
1281
1282	if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
1283		return;
1284
1285	if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
1286		return;
1287
1288	if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
1289				       highpc, &postprologue_addr))
1290		return;
1291
1292	*entrypc = postprologue_addr;
1293}