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/* Unlike dwarf_getsrc_die(), cu_getsrc_die() only returns statement line */
  63static Dwarf_Line *cu_getsrc_die(Dwarf_Die *cu_die, Dwarf_Addr addr)
  64{
  65	Dwarf_Addr laddr;
  66	Dwarf_Lines *lines;
  67	Dwarf_Line *line;
  68	size_t nlines, l, u, n;
  69	bool flag;
  70
  71	if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0 ||
  72	    nlines == 0)
  73		return NULL;
  74
  75	/* Lines are sorted by address, use binary search */
  76	l = 0; u = nlines - 1;
  77	while (l < u) {
  78		n = u - (u - l) / 2;
  79		line = dwarf_onesrcline(lines, n);
  80		if (!line || dwarf_lineaddr(line, &laddr) != 0)
  81			return NULL;
  82		if (addr < laddr)
  83			u = n - 1;
  84		else
  85			l = n;
  86	}
  87	/* Going backward to find the lowest line */
  88	do {
  89		line = dwarf_onesrcline(lines, --l);
  90		if (!line || dwarf_lineaddr(line, &laddr) != 0)
  91			return NULL;
  92	} while (laddr == addr);
  93	l++;
  94	/* Going forward to find the statement line */
  95	do {
  96		line = dwarf_onesrcline(lines, l++);
  97		if (!line || dwarf_lineaddr(line, &laddr) != 0 ||
  98		    dwarf_linebeginstatement(line, &flag) != 0)
  99			return NULL;
 100		if (laddr > addr)
 101			return NULL;
 102	} while (!flag);
 103
 104	return line;
 105}
 106
 107/**
 108 * cu_find_lineinfo - Get a line number and file name for given address
 109 * @cu_die: a CU DIE
 110 * @addr: An address
 111 * @fname: a pointer which returns the file name string
 112 * @lineno: a pointer which returns the line number
 113 *
 114 * Find a line number and file name for @addr in @cu_die.
 115 */
 116int cu_find_lineinfo(Dwarf_Die *cu_die, Dwarf_Addr addr,
 117		     const char **fname, int *lineno)
 118{
 119	Dwarf_Line *line;
 120	Dwarf_Die die_mem;
 121	Dwarf_Addr faddr;
 122
 123	if (die_find_realfunc(cu_die, addr, &die_mem)
 124	    && die_entrypc(&die_mem, &faddr) == 0 &&
 125	    faddr == addr) {
 126		*fname = die_get_decl_file(&die_mem);
 127		dwarf_decl_line(&die_mem, lineno);
 128		goto out;
 129	}
 130
 131	line = cu_getsrc_die(cu_die, addr);
 132	if (line && dwarf_lineno(line, lineno) == 0) {
 133		*fname = dwarf_linesrc(line, NULL, NULL);
 134		if (!*fname)
 135			/* line number is useless without filename */
 136			*lineno = 0;
 137	}
 138
 139out:
 140	return (*lineno && *fname) ? *lineno : -ENOENT;
 141}
 142
 143static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
 144
 145/**
 146 * cu_walk_functions_at - Walk on function DIEs at given address
 147 * @cu_die: A CU DIE
 148 * @addr: An address
 149 * @callback: A callback which called with found DIEs
 150 * @data: A user data
 151 *
 152 * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
 153 * should be subprogram or inlined-subroutines.
 154 */
 155int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
 156		    int (*callback)(Dwarf_Die *, void *), void *data)
 157{
 158	Dwarf_Die die_mem;
 159	Dwarf_Die *sc_die;
 160	int ret = -ENOENT;
 161
 162	/* Inlined function could be recursive. Trace it until fail */
 163	for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
 164	     sc_die != NULL;
 165	     sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
 166				     &die_mem)) {
 167		ret = callback(sc_die, data);
 168		if (ret)
 169			break;
 170	}
 171
 172	return ret;
 173
 174}
 175
 176/**
 177 * die_get_linkage_name - Get the linkage name of the object
 178 * @dw_die: A DIE of the object
 179 *
 180 * Get the linkage name attribute of given @dw_die.
 181 * For C++ binary, the linkage name will be the mangled symbol.
 182 */
 183const char *die_get_linkage_name(Dwarf_Die *dw_die)
 184{
 185	Dwarf_Attribute attr;
 186
 187	if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
 188		return NULL;
 189	return dwarf_formstring(&attr);
 190}
 191
 192/**
 193 * die_compare_name - Compare diename and tname
 194 * @dw_die: a DIE
 195 * @tname: a string of target name
 196 *
 197 * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
 198 */
 199bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
 200{
 201	const char *name;
 202
 203	name = dwarf_diename(dw_die);
 204	return name ? (strcmp(tname, name) == 0) : false;
 205}
 206
 207/**
 208 * die_match_name - Match diename/linkage name and glob
 209 * @dw_die: a DIE
 210 * @glob: a string of target glob pattern
 211 *
 212 * Glob matching the name of @dw_die and @glob. Return false if matching fail.
 213 * This also match linkage name.
 214 */
 215bool die_match_name(Dwarf_Die *dw_die, const char *glob)
 216{
 217	const char *name;
 218
 219	name = dwarf_diename(dw_die);
 220	if (name && strglobmatch(name, glob))
 221		return true;
 222	/* fall back to check linkage name */
 223	name = die_get_linkage_name(dw_die);
 224	if (name && strglobmatch(name, glob))
 225		return true;
 226
 227	return false;
 228}
 229
 230/**
 231 * die_get_call_lineno - Get callsite line number of inline-function instance
 232 * @in_die: a DIE of an inlined function instance
 233 *
 234 * Get call-site line number of @in_die. This means from where the inline
 235 * function is called.
 236 */
 237int die_get_call_lineno(Dwarf_Die *in_die)
 238{
 239	Dwarf_Attribute attr;
 240	Dwarf_Word ret;
 241
 242	if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
 243		return -ENOENT;
 244
 245	dwarf_formudata(&attr, &ret);
 246	return (int)ret;
 247}
 248
 249/**
 250 * die_get_type - Get type DIE
 251 * @vr_die: a DIE of a variable
 252 * @die_mem: where to store a type DIE
 253 *
 254 * Get a DIE of the type of given variable (@vr_die), and store
 255 * it to die_mem. Return NULL if fails to get a type DIE.
 256 */
 257Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 258{
 259	Dwarf_Attribute attr;
 260
 261	if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
 262	    dwarf_formref_die(&attr, die_mem))
 263		return die_mem;
 264	else
 265		return NULL;
 266}
 267
 268/* Get a type die, but skip qualifiers */
 269static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 270{
 271	int tag;
 272
 273	do {
 274		vr_die = die_get_type(vr_die, die_mem);
 275		if (!vr_die)
 276			break;
 277		tag = dwarf_tag(vr_die);
 278	} while (tag == DW_TAG_const_type ||
 279		 tag == DW_TAG_restrict_type ||
 280		 tag == DW_TAG_volatile_type ||
 281		 tag == DW_TAG_shared_type);
 282
 283	return vr_die;
 284}
 285
 286/**
 287 * die_get_real_type - Get a type die, but skip qualifiers and typedef
 288 * @vr_die: a DIE of a variable
 289 * @die_mem: where to store a type DIE
 290 *
 291 * Get a DIE of the type of given variable (@vr_die), and store
 292 * it to die_mem. Return NULL if fails to get a type DIE.
 293 * If the type is qualifiers (e.g. const) or typedef, this skips it
 294 * and tries to find real type (structure or basic types, e.g. int).
 295 */
 296Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 297{
 298	do {
 299		vr_die = __die_get_real_type(vr_die, die_mem);
 300	} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
 301
 302	return vr_die;
 303}
 304
 305/* Get attribute and translate it as a udata */
 306static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
 307			      Dwarf_Word *result)
 308{
 309	Dwarf_Attribute attr;
 310
 311	if (dwarf_attr_integrate(tp_die, attr_name, &attr) == NULL ||
 312	    dwarf_formudata(&attr, result) != 0)
 313		return -ENOENT;
 314
 315	return 0;
 316}
 317
 318/**
 319 * die_is_signed_type - Check whether a type DIE is signed or not
 320 * @tp_die: a DIE of a type
 321 *
 322 * Get the encoding of @tp_die and return true if the encoding
 323 * is signed.
 324 */
 325bool die_is_signed_type(Dwarf_Die *tp_die)
 326{
 327	Dwarf_Word ret;
 328
 329	if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
 330		return false;
 331
 332	return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
 333		ret == DW_ATE_signed_fixed);
 334}
 335
 336/**
 337 * die_is_func_def - Ensure that this DIE is a subprogram and definition
 338 * @dw_die: a DIE
 339 *
 340 * Ensure that this DIE is a subprogram and NOT a declaration. This
 341 * returns true if @dw_die is a function definition.
 342 **/
 343bool die_is_func_def(Dwarf_Die *dw_die)
 344{
 345	Dwarf_Attribute attr;
 346	Dwarf_Addr addr = 0;
 347
 348	if (dwarf_tag(dw_die) != DW_TAG_subprogram)
 349		return false;
 350
 351	if (dwarf_attr(dw_die, DW_AT_declaration, &attr))
 352		return false;
 353
 354	/*
 355	 * DW_AT_declaration can be lost from function declaration
 356	 * by gcc's bug #97060.
 357	 * So we need to check this subprogram DIE has DW_AT_inline
 358	 * or an entry address.
 359	 */
 360	if (!dwarf_attr(dw_die, DW_AT_inline, &attr) &&
 361	    die_entrypc(dw_die, &addr) < 0)
 362		return false;
 363
 364	return true;
 365}
 366
 367/**
 368 * die_entrypc - Returns entry PC (the lowest address) of a DIE
 369 * @dw_die: a DIE
 370 * @addr: where to store entry PC
 371 *
 372 * Since dwarf_entrypc() does not return entry PC if the DIE has only address
 373 * range, we have to use this to retrieve the lowest address from the address
 374 * range attribute.
 375 */
 376int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
 377{
 378	Dwarf_Addr base, end;
 379	Dwarf_Attribute attr;
 380
 381	if (!addr)
 382		return -EINVAL;
 383
 384	if (dwarf_entrypc(dw_die, addr) == 0)
 385		return 0;
 386
 387	/*
 388	 *  Since the dwarf_ranges() will return 0 if there is no
 389	 * DW_AT_ranges attribute, we should check it first.
 390	 */
 391	if (!dwarf_attr(dw_die, DW_AT_ranges, &attr))
 392		return -ENOENT;
 393
 394	return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
 395}
 396
 397/**
 398 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
 399 * @dw_die: a DIE
 400 *
 401 * Ensure that this DIE is an instance (which has an entry address).
 402 * This returns true if @dw_die is a function instance. If not, the @dw_die
 403 * must be a prototype. You can use die_walk_instances() to find actual
 404 * instances.
 405 **/
 406bool die_is_func_instance(Dwarf_Die *dw_die)
 407{
 408	Dwarf_Addr tmp;
 409	Dwarf_Attribute attr_mem;
 410	int tag = dwarf_tag(dw_die);
 411
 412	if (tag != DW_TAG_subprogram &&
 413	    tag != DW_TAG_inlined_subroutine)
 414		return false;
 415
 416	return dwarf_entrypc(dw_die, &tmp) == 0 ||
 417		dwarf_attr(dw_die, DW_AT_ranges, &attr_mem) != NULL;
 418}
 419
 420/**
 421 * die_get_data_member_location - Get the data-member offset
 422 * @mb_die: a DIE of a member of a data structure
 423 * @offs: The offset of the member in the data structure
 424 *
 425 * Get the offset of @mb_die in the data structure including @mb_die, and
 426 * stores result offset to @offs. If any error occurs this returns errno.
 427 */
 428int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
 429{
 430	Dwarf_Attribute attr;
 431	Dwarf_Op *expr;
 432	size_t nexpr;
 433	int ret;
 434
 435	if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
 436		return -ENOENT;
 437
 438	if (dwarf_formudata(&attr, offs) != 0) {
 439		/* DW_AT_data_member_location should be DW_OP_plus_uconst */
 440		ret = dwarf_getlocation(&attr, &expr, &nexpr);
 441		if (ret < 0 || nexpr == 0)
 442			return -ENOENT;
 443
 444		if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
 445			pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
 446				 expr[0].atom, nexpr);
 447			return -ENOTSUP;
 448		}
 449		*offs = (Dwarf_Word)expr[0].number;
 450	}
 451	return 0;
 452}
 453
 454/* Get the call file index number in CU DIE */
 455static int die_get_call_fileno(Dwarf_Die *in_die)
 456{
 457	Dwarf_Word idx;
 458
 459	if (die_get_attr_udata(in_die, DW_AT_call_file, &idx) == 0)
 460		return (int)idx;
 461	else
 462		return -ENOENT;
 463}
 464
 465/* Get the declared file index number in CU DIE */
 466static int die_get_decl_fileno(Dwarf_Die *pdie)
 467{
 468	Dwarf_Word idx;
 469
 470	if (die_get_attr_udata(pdie, DW_AT_decl_file, &idx) == 0)
 471		return (int)idx;
 472	else
 473		return -ENOENT;
 474}
 475
 476/* Return the file name by index */
 477static const char *die_get_file_name(Dwarf_Die *dw_die, int idx)
 478{
 479	Dwarf_Die cu_die;
 480	Dwarf_Files *files;
 
 481
 482	if (idx < 0 || !dwarf_diecu(dw_die, &cu_die, NULL, NULL) ||
 
 483	    dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
 484		return NULL;
 485
 486	return dwarf_filesrc(files, idx, NULL, NULL);
 487}
 488
 489/**
 490 * die_get_call_file - Get callsite file name of inlined function instance
 491 * @in_die: a DIE of an inlined function instance
 492 *
 493 * Get call-site file name of @in_die. This means from which file the inline
 494 * function is called.
 495 */
 496const char *die_get_call_file(Dwarf_Die *in_die)
 497{
 498	return die_get_file_name(in_die, die_get_call_fileno(in_die));
 499}
 500
 501/**
 502 * die_get_decl_file - Find the declared file name of this DIE
 503 * @dw_die: a DIE for something declared.
 504 *
 505 * Get declared file name of @dw_die.
 506 * NOTE: Since some version of clang DWARF5 implementation incorrectly uses
 507 * file index 0 for DW_AT_decl_file, die_get_decl_file() will return NULL for
 508 * such cases. Use this function instead.
 509 */
 510const char *die_get_decl_file(Dwarf_Die *dw_die)
 511{
 512	return die_get_file_name(dw_die, die_get_decl_fileno(dw_die));
 513}
 514
 515/**
 516 * die_find_child - Generic DIE search function in DIE tree
 517 * @rt_die: a root DIE
 518 * @callback: a callback function
 519 * @data: a user data passed to the callback function
 520 * @die_mem: a buffer for result DIE
 521 *
 522 * Trace DIE tree from @rt_die and call @callback for each child DIE.
 523 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
 524 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
 525 * this continues to trace the tree. Optionally, @callback can return
 526 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
 527 * the children and trace only the siblings respectively.
 528 * Returns NULL if @callback can't find any appropriate DIE.
 529 */
 530Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
 531			  int (*callback)(Dwarf_Die *, void *),
 532			  void *data, Dwarf_Die *die_mem)
 533{
 534	Dwarf_Die child_die;
 535	int ret;
 536
 537	ret = dwarf_child(rt_die, die_mem);
 538	if (ret != 0)
 539		return NULL;
 540
 541	do {
 542		ret = callback(die_mem, data);
 543		if (ret == DIE_FIND_CB_END)
 544			return die_mem;
 545
 546		if ((ret & DIE_FIND_CB_CHILD) &&
 547		    die_find_child(die_mem, callback, data, &child_die)) {
 548			memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
 549			return die_mem;
 550		}
 551	} while ((ret & DIE_FIND_CB_SIBLING) &&
 552		 dwarf_siblingof(die_mem, die_mem) == 0);
 553
 554	return NULL;
 555}
 556
 557struct __addr_die_search_param {
 558	Dwarf_Addr	addr;
 559	Dwarf_Die	*die_mem;
 560};
 561
 562static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
 563{
 564	struct __addr_die_search_param *ad = data;
 565	Dwarf_Addr addr = 0;
 566
 567	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
 568	    !dwarf_highpc(fn_die, &addr) &&
 569	    addr == ad->addr) {
 570		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
 571		return DWARF_CB_ABORT;
 572	}
 573	return DWARF_CB_OK;
 574}
 575
 576/**
 577 * die_find_tailfunc - Search for a non-inlined function with tail call at
 578 * given address
 579 * @cu_die: a CU DIE which including @addr
 580 * @addr: target address
 581 * @die_mem: a buffer for result DIE
 582 *
 583 * Search for a non-inlined function DIE with tail call at @addr. Stores the
 584 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 585 */
 586Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
 587				    Dwarf_Die *die_mem)
 588{
 589	struct __addr_die_search_param ad;
 590	ad.addr = addr;
 591	ad.die_mem = die_mem;
 592	/* dwarf_getscopes can't find subprogram. */
 593	if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
 594		return NULL;
 595	else
 596		return die_mem;
 597}
 598
 599/* die_find callback for non-inlined function search */
 600static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
 601{
 602	struct __addr_die_search_param *ad = data;
 603
 604	/*
 605	 * Since a declaration entry doesn't has given pc, this always returns
 606	 * function definition entry.
 607	 */
 608	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
 609	    dwarf_haspc(fn_die, ad->addr)) {
 610		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
 611		return DWARF_CB_ABORT;
 612	}
 613	return DWARF_CB_OK;
 614}
 615
 616/**
 617 * die_find_realfunc - Search a non-inlined function at given address
 618 * @cu_die: a CU DIE which including @addr
 619 * @addr: target address
 620 * @die_mem: a buffer for result DIE
 621 *
 622 * Search a non-inlined function DIE which includes @addr. Stores the
 623 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 624 */
 625Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
 626				    Dwarf_Die *die_mem)
 627{
 628	struct __addr_die_search_param ad;
 629	ad.addr = addr;
 630	ad.die_mem = die_mem;
 631	/* dwarf_getscopes can't find subprogram. */
 632	if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
 633		return NULL;
 634	else
 635		return die_mem;
 636}
 637
 638/* die_find callback for inline function search */
 639static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
 640{
 641	Dwarf_Addr *addr = data;
 642
 643	if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
 644	    dwarf_haspc(die_mem, *addr))
 645		return DIE_FIND_CB_END;
 646
 647	return DIE_FIND_CB_CONTINUE;
 648}
 649
 650/**
 651 * die_find_top_inlinefunc - Search the top inlined function at given address
 652 * @sp_die: a subprogram DIE which including @addr
 653 * @addr: target address
 654 * @die_mem: a buffer for result DIE
 655 *
 656 * Search an inlined function DIE which includes @addr. Stores the
 657 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 658 * Even if several inlined functions are expanded recursively, this
 659 * doesn't trace it down, and returns the topmost one.
 660 */
 661Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 662				   Dwarf_Die *die_mem)
 663{
 664	return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
 665}
 666
 667/**
 668 * die_find_inlinefunc - Search an inlined function at given address
 669 * @sp_die: a subprogram DIE which including @addr
 670 * @addr: target address
 671 * @die_mem: a buffer for result DIE
 672 *
 673 * Search an inlined function DIE which includes @addr. Stores the
 674 * DIE to @die_mem and returns it if found. Returns NULL if failed.
 675 * If several inlined functions are expanded recursively, this trace
 676 * it down and returns deepest one.
 677 */
 678Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 679			       Dwarf_Die *die_mem)
 680{
 681	Dwarf_Die tmp_die;
 682
 683	sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
 684	if (!sp_die)
 685		return NULL;
 686
 687	/* Inlined function could be recursive. Trace it until fail */
 688	while (sp_die) {
 689		memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
 690		sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
 691					&tmp_die);
 692	}
 693
 694	return die_mem;
 695}
 696
 697struct __instance_walk_param {
 698	void    *addr;
 699	int	(*callback)(Dwarf_Die *, void *);
 700	void    *data;
 701	int	retval;
 702};
 703
 704static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
 705{
 706	struct __instance_walk_param *iwp = data;
 707	Dwarf_Attribute attr_mem;
 708	Dwarf_Die origin_mem;
 709	Dwarf_Attribute *attr;
 710	Dwarf_Die *origin;
 711	int tmp;
 712
 713	if (!die_is_func_instance(inst))
 714		return DIE_FIND_CB_CONTINUE;
 715
 716	attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
 717	if (attr == NULL)
 718		return DIE_FIND_CB_CONTINUE;
 719
 720	origin = dwarf_formref_die(attr, &origin_mem);
 721	if (origin == NULL || origin->addr != iwp->addr)
 722		return DIE_FIND_CB_CONTINUE;
 723
 724	/* Ignore redundant instances */
 725	if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
 726		dwarf_decl_line(origin, &tmp);
 727		if (die_get_call_lineno(inst) == tmp) {
 728			tmp = die_get_decl_fileno(origin);
 729			if (die_get_call_fileno(inst) == tmp)
 730				return DIE_FIND_CB_CONTINUE;
 731		}
 732	}
 733
 734	iwp->retval = iwp->callback(inst, iwp->data);
 735
 736	return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
 737}
 738
 739/**
 740 * die_walk_instances - Walk on instances of given DIE
 741 * @or_die: an abstract original DIE
 742 * @callback: a callback function which is called with instance DIE
 743 * @data: user data
 744 *
 745 * Walk on the instances of give @in_die. @in_die must be an inlined function
 746 * declaration. This returns the return value of @callback if it returns
 747 * non-zero value, or -ENOENT if there is no instance.
 748 */
 749int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
 750		       void *data)
 751{
 752	Dwarf_Die cu_die;
 753	Dwarf_Die die_mem;
 754	struct __instance_walk_param iwp = {
 755		.addr = or_die->addr,
 756		.callback = callback,
 757		.data = data,
 758		.retval = -ENOENT,
 759	};
 760
 761	if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
 762		return -ENOENT;
 763
 764	die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
 765
 766	return iwp.retval;
 767}
 768
 769/* Line walker internal parameters */
 770struct __line_walk_param {
 771	bool recursive;
 772	line_walk_callback_t callback;
 773	void *data;
 774	int retval;
 775};
 776
 777static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
 778{
 779	struct __line_walk_param *lw = data;
 780	Dwarf_Addr addr = 0;
 781	const char *fname;
 782	int lineno;
 783
 784	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
 785		fname = die_get_call_file(in_die);
 786		lineno = die_get_call_lineno(in_die);
 787		if (fname && lineno > 0 && die_entrypc(in_die, &addr) == 0) {
 788			lw->retval = lw->callback(fname, lineno, addr, lw->data);
 789			if (lw->retval != 0)
 790				return DIE_FIND_CB_END;
 791		}
 792		if (!lw->recursive)
 793			return DIE_FIND_CB_SIBLING;
 794	}
 795
 796	if (addr) {
 797		fname = die_get_decl_file(in_die);
 798		if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
 799			lw->retval = lw->callback(fname, lineno, addr, lw->data);
 800			if (lw->retval != 0)
 801				return DIE_FIND_CB_END;
 802		}
 803	}
 804
 805	/* Continue to search nested inlined function call-sites */
 806	return DIE_FIND_CB_CONTINUE;
 807}
 808
 809/* Walk on lines of blocks included in given DIE */
 810static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
 811				line_walk_callback_t callback, void *data)
 812{
 813	struct __line_walk_param lw = {
 814		.recursive = recursive,
 815		.callback = callback,
 816		.data = data,
 817		.retval = 0,
 818	};
 819	Dwarf_Die die_mem;
 820	Dwarf_Addr addr;
 821	const char *fname;
 822	int lineno;
 823
 824	/* Handle function declaration line */
 825	fname = die_get_decl_file(sp_die);
 826	if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
 827	    die_entrypc(sp_die, &addr) == 0) {
 828		lw.retval = callback(fname, lineno, addr, data);
 829		if (lw.retval != 0)
 830			goto done;
 831	}
 832	die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
 833done:
 834	return lw.retval;
 835}
 836
 837static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
 838{
 839	struct __line_walk_param *lw = data;
 840
 841	/*
 842	 * Since inlined function can include another inlined function in
 843	 * the same file, we need to walk in it recursively.
 844	 */
 845	lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
 846	if (lw->retval != 0)
 847		return DWARF_CB_ABORT;
 848
 849	return DWARF_CB_OK;
 850}
 851
 852/**
 853 * die_walk_lines - Walk on lines inside given DIE
 854 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
 855 * @callback: callback routine
 856 * @data: user data
 857 *
 858 * Walk on all lines inside given @rt_die and call @callback on each line.
 859 * If the @rt_die is a function, walk only on the lines inside the function,
 860 * otherwise @rt_die must be a CU DIE.
 861 * Note that this walks not only dwarf line list, but also function entries
 862 * and inline call-site.
 863 */
 864int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
 865{
 866	Dwarf_Lines *lines;
 867	Dwarf_Line *line;
 868	Dwarf_Addr addr;
 869	const char *fname, *decf = NULL, *inf = NULL;
 870	int lineno, ret = 0;
 871	int decl = 0, inl;
 872	Dwarf_Die die_mem, *cu_die;
 873	size_t nlines, i;
 874	bool flag;
 875
 876	/* Get the CU die */
 877	if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
 878		cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
 879		dwarf_decl_line(rt_die, &decl);
 880		decf = die_get_decl_file(rt_die);
 881		if (!decf) {
 882			pr_debug2("Failed to get the declared file name of %s\n",
 883				  dwarf_diename(rt_die));
 884			return -EINVAL;
 885		}
 886	} else
 887		cu_die = rt_die;
 888	if (!cu_die) {
 889		pr_debug2("Failed to get CU from given DIE.\n");
 890		return -EINVAL;
 891	}
 892
 893	/* Get lines list in the CU */
 894	if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
 895		pr_debug2("Failed to get source lines on this CU.\n");
 896		return -ENOENT;
 897	}
 898	pr_debug2("Get %zd lines from this CU\n", nlines);
 899
 900	/* Walk on the lines on lines list */
 901	for (i = 0; i < nlines; i++) {
 902		line = dwarf_onesrcline(lines, i);
 903		if (line == NULL ||
 904		    dwarf_lineno(line, &lineno) != 0 ||
 905		    dwarf_lineaddr(line, &addr) != 0) {
 906			pr_debug2("Failed to get line info. "
 907				  "Possible error in debuginfo.\n");
 908			continue;
 909		}
 910		/* Skip end-of-sequence */
 911		if (dwarf_lineendsequence(line, &flag) != 0 || flag)
 912			continue;
 913		/* Skip Non statement line-info */
 914		if (dwarf_linebeginstatement(line, &flag) != 0 || !flag)
 915			continue;
 916		/* Filter lines based on address */
 917		if (rt_die != cu_die) {
 918			/*
 919			 * Address filtering
 920			 * The line is included in given function, and
 921			 * no inline block includes it.
 922			 */
 923			if (!dwarf_haspc(rt_die, addr))
 924				continue;
 925
 926			if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
 927				/* Call-site check */
 928				inf = die_get_call_file(&die_mem);
 929				if ((inf && !strcmp(inf, decf)) &&
 930				    die_get_call_lineno(&die_mem) == lineno)
 931					goto found;
 932
 933				dwarf_decl_line(&die_mem, &inl);
 934				if (inl != decl ||
 935				    decf != die_get_decl_file(&die_mem))
 936					continue;
 937			}
 938		}
 939found:
 940		/* Get source line */
 941		fname = dwarf_linesrc(line, NULL, NULL);
 942
 943		ret = callback(fname, lineno, addr, data);
 944		if (ret != 0)
 945			return ret;
 946	}
 947
 948	/*
 949	 * Dwarf lines doesn't include function declarations and inlined
 950	 * subroutines. We have to check functions list or given function.
 951	 */
 952	if (rt_die != cu_die)
 953		/*
 954		 * Don't need walk inlined functions recursively, because
 955		 * inner inlined functions don't have the lines of the
 956		 * specified function.
 957		 */
 958		ret = __die_walk_funclines(rt_die, false, callback, data);
 959	else {
 960		struct __line_walk_param param = {
 961			.callback = callback,
 962			.data = data,
 963			.retval = 0,
 964		};
 965		dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
 966		ret = param.retval;
 967	}
 968
 969	return ret;
 970}
 971
 972struct __find_variable_param {
 973	const char *name;
 974	Dwarf_Addr addr;
 975};
 976
 977static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
 978{
 979	struct __find_variable_param *fvp = data;
 980	Dwarf_Attribute attr;
 981	int tag;
 982
 983	tag = dwarf_tag(die_mem);
 984	if ((tag == DW_TAG_formal_parameter ||
 985	     tag == DW_TAG_variable) &&
 986	    die_compare_name(die_mem, fvp->name) &&
 987	/*
 988	 * Does the DIE have location information or const value
 989	 * or external instance?
 990	 */
 991	    (dwarf_attr(die_mem, DW_AT_external, &attr) ||
 992	     dwarf_attr(die_mem, DW_AT_location, &attr) ||
 993	     dwarf_attr(die_mem, DW_AT_const_value, &attr)))
 994		return DIE_FIND_CB_END;
 995	if (dwarf_haspc(die_mem, fvp->addr))
 996		return DIE_FIND_CB_CONTINUE;
 997	else
 998		return DIE_FIND_CB_SIBLING;
 999}
1000
1001/**
1002 * die_find_variable_at - Find a given name variable at given address
1003 * @sp_die: a function DIE
1004 * @name: variable name
1005 * @addr: address
1006 * @die_mem: a buffer for result DIE
1007 *
1008 * Find a variable DIE called @name at @addr in @sp_die.
1009 */
1010Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
1011				Dwarf_Addr addr, Dwarf_Die *die_mem)
1012{
1013	struct __find_variable_param fvp = { .name = name, .addr = addr};
1014
1015	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
1016			      die_mem);
1017}
1018
1019static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
1020{
1021	const char *name = data;
1022
1023	if (dwarf_tag(die_mem) == DW_TAG_member) {
1024		if (die_compare_name(die_mem, name))
1025			return DIE_FIND_CB_END;
1026		else if (!dwarf_diename(die_mem)) {	/* Unnamed structure */
1027			Dwarf_Die type_die, tmp_die;
1028			if (die_get_type(die_mem, &type_die) &&
1029			    die_find_member(&type_die, name, &tmp_die))
1030				return DIE_FIND_CB_END;
1031		}
1032	}
1033	return DIE_FIND_CB_SIBLING;
1034}
1035
1036/**
1037 * die_find_member - Find a given name member in a data structure
1038 * @st_die: a data structure type DIE
1039 * @name: member name
1040 * @die_mem: a buffer for result DIE
1041 *
1042 * Find a member DIE called @name in @st_die.
1043 */
1044Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
1045			   Dwarf_Die *die_mem)
1046{
1047	return die_find_child(st_die, __die_find_member_cb, (void *)name,
1048			      die_mem);
1049}
1050
1051/**
1052 * die_get_typename - Get the name of given variable DIE
1053 * @vr_die: a variable DIE
1054 * @buf: a strbuf for result type name
1055 *
1056 * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
1057 * and Return -ENOENT if failed to find type name.
1058 * Note that the result will stores typedef name if possible, and stores
1059 * "*(function_type)" if the type is a function pointer.
1060 */
1061int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
1062{
1063	Dwarf_Die type;
1064	int tag, ret;
1065	const char *tmp = "";
1066
1067	if (__die_get_real_type(vr_die, &type) == NULL)
1068		return -ENOENT;
1069
1070	tag = dwarf_tag(&type);
1071	if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
1072		tmp = "*";
1073	else if (tag == DW_TAG_subroutine_type) {
1074		/* Function pointer */
1075		return strbuf_add(buf, "(function_type)", 15);
1076	} else {
1077		if (!dwarf_diename(&type))
1078			return -ENOENT;
1079		if (tag == DW_TAG_union_type)
1080			tmp = "union ";
1081		else if (tag == DW_TAG_structure_type)
1082			tmp = "struct ";
1083		else if (tag == DW_TAG_enumeration_type)
1084			tmp = "enum ";
 
 
1085		/* Write a base name */
1086		return strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type));
1087	}
1088	ret = die_get_typename(&type, buf);
1089	return ret ? ret : strbuf_addstr(buf, tmp);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1090}
1091
1092/**
1093 * die_get_varname - Get the name and type of given variable DIE
1094 * @vr_die: a variable DIE
1095 * @buf: a strbuf for type and variable name
1096 *
1097 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
1098 */
1099int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
1100{
1101	int ret;
1102
1103	ret = die_get_typename(vr_die, buf);
1104	if (ret < 0) {
1105		pr_debug("Failed to get type, make it unknown.\n");
1106		ret = strbuf_add(buf, " (unknown_type)", 14);
1107	}
1108
1109	return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
1110}
1111
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1112#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
1113/**
1114 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
1115 * @sp_die: a subprogram DIE
1116 * @vr_die: a variable DIE
1117 * @buf: a strbuf for variable byte offset range
1118 *
1119 * Get the innermost scope range of @vr_die and stores it in @buf as
1120 * "@<function_name+[NN-NN,NN-NN]>".
1121 */
1122static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
1123				struct strbuf *buf)
1124{
1125	Dwarf_Die *scopes;
1126	int count;
1127	size_t offset = 0;
1128	Dwarf_Addr base;
1129	Dwarf_Addr start, end;
1130	Dwarf_Addr entry;
1131	int ret;
1132	bool first = true;
1133	const char *name;
1134
1135	ret = die_entrypc(sp_die, &entry);
1136	if (ret)
1137		return ret;
1138
1139	name = dwarf_diename(sp_die);
1140	if (!name)
1141		return -ENOENT;
1142
1143	count = dwarf_getscopes_die(vr_die, &scopes);
1144
1145	/* (*SCOPES)[1] is the DIE for the scope containing that scope */
1146	if (count <= 1) {
1147		ret = -EINVAL;
1148		goto out;
1149	}
1150
1151	while ((offset = dwarf_ranges(&scopes[1], offset, &base,
1152					&start, &end)) > 0) {
1153		start -= entry;
1154		end -= entry;
1155
1156		if (first) {
1157			ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1158					  name, start, end);
1159			first = false;
1160		} else {
1161			ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1162					  start, end);
1163		}
1164		if (ret < 0)
1165			goto out;
1166	}
1167
1168	if (!first)
1169		ret = strbuf_add(buf, "]>", 2);
1170
1171out:
1172	free(scopes);
1173	return ret;
1174}
1175
1176/**
1177 * die_get_var_range - Get byte offset range of given variable DIE
1178 * @sp_die: a subprogram DIE
1179 * @vr_die: a variable DIE
1180 * @buf: a strbuf for type and variable name and byte offset range
1181 *
1182 * Get the byte offset range of @vr_die and stores it in @buf as
1183 * "@<function_name+[NN-NN,NN-NN]>".
1184 */
1185int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
1186{
1187	int ret = 0;
1188	Dwarf_Addr base;
1189	Dwarf_Addr start, end;
1190	Dwarf_Addr entry;
1191	Dwarf_Op *op;
1192	size_t nops;
1193	size_t offset = 0;
1194	Dwarf_Attribute attr;
1195	bool first = true;
1196	const char *name;
1197
1198	ret = die_entrypc(sp_die, &entry);
1199	if (ret)
1200		return ret;
1201
1202	name = dwarf_diename(sp_die);
1203	if (!name)
1204		return -ENOENT;
1205
1206	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
1207		return -EINVAL;
1208
1209	while ((offset = dwarf_getlocations(&attr, offset, &base,
1210					&start, &end, &op, &nops)) > 0) {
1211		if (start == 0) {
1212			/* Single Location Descriptions */
1213			ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
1214			goto out;
1215		}
1216
1217		/* Location Lists */
1218		start -= entry;
1219		end -= entry;
1220		if (first) {
1221			ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1222					  name, start, end);
1223			first = false;
1224		} else {
1225			ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1226					  start, end);
1227		}
1228		if (ret < 0)
1229			goto out;
1230	}
1231
1232	if (!first)
1233		ret = strbuf_add(buf, "]>", 2);
1234out:
1235	return ret;
1236}
1237#else
1238int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
1239		      Dwarf_Die *vr_die __maybe_unused,
1240		      struct strbuf *buf __maybe_unused)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1241{
1242	return -ENOTSUP;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1243}
1244#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1245
1246/*
1247 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list
1248 * @vr_die: a variable DIE
1249 */
1250static bool die_has_loclist(Dwarf_Die *vr_die)
1251{
1252	Dwarf_Attribute loc;
1253	int tag = dwarf_tag(vr_die);
1254
1255	if (tag != DW_TAG_formal_parameter &&
1256	    tag != DW_TAG_variable)
1257		return false;
1258
1259	return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
1260		dwarf_whatform(&loc) == DW_FORM_sec_offset);
1261}
1262
1263/*
1264 * die_is_optimized_target - Check if target program is compiled with
1265 * optimization
1266 * @cu_die: a CU DIE
1267 *
1268 * For any object in given CU whose DW_AT_location is a location list,
1269 * target program is compiled with optimization. This is applicable to
1270 * clang as well.
1271 */
1272bool die_is_optimized_target(Dwarf_Die *cu_die)
1273{
1274	Dwarf_Die tmp_die;
1275
1276	if (die_has_loclist(cu_die))
1277		return true;
1278
1279	if (!dwarf_child(cu_die, &tmp_die) &&
1280	    die_is_optimized_target(&tmp_die))
1281		return true;
1282
1283	if (!dwarf_siblingof(cu_die, &tmp_die) &&
1284	    die_is_optimized_target(&tmp_die))
1285		return true;
1286
1287	return false;
1288}
1289
1290/*
1291 * die_search_idx - Search index of given line address
1292 * @lines: Line records of single CU
1293 * @nr_lines: Number of @lines
1294 * @addr: address we are looking for
1295 * @idx: index to be set by this function (return value)
1296 *
1297 * Search for @addr by looping over every lines of CU. If address
1298 * matches, set index of that line in @idx. Note that single source
1299 * line can have multiple line records. i.e. single source line can
1300 * have multiple index.
1301 */
1302static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
1303			   Dwarf_Addr addr, unsigned long *idx)
1304{
1305	unsigned long i;
1306	Dwarf_Addr tmp;
1307
1308	for (i = 0; i < nr_lines; i++) {
1309		if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
1310			return false;
1311
1312		if (tmp == addr) {
1313			*idx = i;
1314			return true;
1315		}
1316	}
1317	return false;
1318}
1319
1320/*
1321 * die_get_postprologue_addr - Search next address after function prologue
1322 * @entrypc_idx: entrypc index
1323 * @lines: Line records of single CU
1324 * @nr_lines: Number of @lines
1325 * @hignpc: high PC address of function
1326 * @postprologue_addr: Next address after function prologue (return value)
1327 *
1328 * Look for prologue-end marker. If there is no explicit marker, return
1329 * address of next line record or next source line.
1330 */
1331static bool die_get_postprologue_addr(unsigned long entrypc_idx,
1332				      Dwarf_Lines *lines,
1333				      unsigned long nr_lines,
1334				      Dwarf_Addr highpc,
1335				      Dwarf_Addr *postprologue_addr)
1336{
1337	unsigned long i;
1338	int entrypc_lno, lno;
1339	Dwarf_Line *line;
1340	Dwarf_Addr addr;
1341	bool p_end;
1342
1343	/* entrypc_lno is actual source line number */
1344	line = dwarf_onesrcline(lines, entrypc_idx);
1345	if (dwarf_lineno(line, &entrypc_lno))
1346		return false;
1347
1348	for (i = entrypc_idx; i < nr_lines; i++) {
1349		line = dwarf_onesrcline(lines, i);
1350
1351		if (dwarf_lineaddr(line, &addr) ||
1352		    dwarf_lineno(line, &lno)    ||
1353		    dwarf_lineprologueend(line, &p_end))
1354			return false;
1355
1356		/* highpc is exclusive. [entrypc,highpc) */
1357		if (addr >= highpc)
1358			break;
1359
1360		/* clang supports prologue-end marker */
1361		if (p_end)
1362			break;
1363
1364		/* Actual next line in source */
1365		if (lno != entrypc_lno)
1366			break;
1367
1368		/*
1369		 * Single source line can have multiple line records.
1370		 * For Example,
1371		 *     void foo() { printf("hello\n"); }
1372		 * contains two line records. One points to declaration and
1373		 * other points to printf() line. Variable 'lno' won't get
1374		 * incremented in this case but 'i' will.
1375		 */
1376		if (i != entrypc_idx)
1377			break;
1378	}
1379
1380	dwarf_lineaddr(line, postprologue_addr);
1381	if (*postprologue_addr >= highpc)
1382		dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
1383			       postprologue_addr);
1384
1385	return true;
1386}
1387
1388/*
1389 * die_skip_prologue - Use next address after prologue as probe location
1390 * @sp_die: a subprogram DIE
1391 * @cu_die: a CU DIE
1392 * @entrypc: entrypc of the function
1393 *
1394 * Function prologue prepares stack and registers before executing function
1395 * logic. When target program is compiled without optimization, function
1396 * parameter information is only valid after prologue. When we probe entrypc
1397 * of the function, and try to record function parameter, it contains
1398 * garbage value.
1399 */
1400void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
1401		       Dwarf_Addr *entrypc)
1402{
1403	size_t nr_lines = 0;
1404	unsigned long entrypc_idx = 0;
1405	Dwarf_Lines *lines = NULL;
1406	Dwarf_Addr postprologue_addr;
1407	Dwarf_Addr highpc;
1408
1409	if (dwarf_highpc(sp_die, &highpc))
1410		return;
1411
1412	if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
1413		return;
1414
1415	if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
1416		return;
1417
1418	if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
1419				       highpc, &postprologue_addr))
1420		return;
1421
1422	*entrypc = postprologue_addr;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1423}