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- /* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line).
- Copyright (C) 1998-2022 Free Software Foundation, Inc.
- Written by Gavin Romig-Koch of Cygnus Solutions (gavin@cygnus.com).
- This file is part of BFD.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or (at
- your option) any later version.
- This program is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
- MA 02110-1301, USA. */
- #include "sysdep.h"
- #include "bfd.h"
- #include "libiberty.h"
- #include "libbfd.h"
- #include "elf-bfd.h"
- #include "elf/dwarf.h"
- /* dwarf1_debug is the starting point for all dwarf1 info. */
- struct dwarf1_debug
- {
- /* The bfd we are working with. */
- bfd* abfd;
- /* Pointer to the symbol table. */
- asymbol** syms;
- /* List of already parsed compilation units. */
- struct dwarf1_unit* lastUnit;
- /* The buffer for the .debug section.
- Zero indicates that the .debug section failed to load. */
- bfd_byte *debug_section;
- /* Pointer to the end of the .debug_info section memory buffer. */
- bfd_byte *debug_section_end;
- /* The buffer for the .line section. */
- bfd_byte *line_section;
- /* End of that buffer. */
- bfd_byte *line_section_end;
- /* The current or next unread die within the .debug section. */
- bfd_byte *currentDie;
- };
- /* One dwarf1_unit for each parsed compilation unit die. */
- struct dwarf1_unit
- {
- /* Linked starting from stash->lastUnit. */
- struct dwarf1_unit* prev;
- /* Name of the compilation unit. */
- char *name;
- /* The highest and lowest address used in the compilation unit. */
- unsigned long low_pc;
- unsigned long high_pc;
- /* Does this unit have a statement list? */
- int has_stmt_list;
- /* If any, the offset of the line number table in the .line section. */
- unsigned long stmt_list_offset;
- /* If non-zero, a pointer to the first child of this unit. */
- bfd_byte *first_child;
- /* How many line entries? */
- unsigned long line_count;
- /* The decoded line number table (line_count entries). */
- struct linenumber* linenumber_table;
- /* The list of functions in this unit. */
- struct dwarf1_func* func_list;
- };
- /* One dwarf1_func for each parsed function die. */
- struct dwarf1_func
- {
- /* Linked starting from aUnit->func_list. */
- struct dwarf1_func* prev;
- /* Name of function. */
- char* name;
- /* The highest and lowest address used in the compilation unit. */
- unsigned long low_pc;
- unsigned long high_pc;
- };
- /* Used to return info about a parsed die. */
- struct die_info
- {
- unsigned long length;
- unsigned long sibling;
- unsigned long low_pc;
- unsigned long high_pc;
- unsigned long stmt_list_offset;
- char* name;
- int has_stmt_list;
- unsigned short tag;
- };
- /* Parsed line number information. */
- struct linenumber
- {
- /* First address in the line. */
- unsigned long addr;
- /* The line number. */
- unsigned long linenumber;
- };
- /* Find the form of an attr, from the attr field. */
- #define FORM_FROM_ATTR(attr) ((attr) & 0xF) /* Implicitly specified. */
- /* Return a newly allocated dwarf1_unit. It should be cleared and
- then attached into the 'stash' at 'stash->lastUnit'. */
- static struct dwarf1_unit*
- alloc_dwarf1_unit (struct dwarf1_debug* stash)
- {
- size_t amt = sizeof (struct dwarf1_unit);
- struct dwarf1_unit* x = (struct dwarf1_unit *) bfd_zalloc (stash->abfd, amt);
- if (x)
- {
- x->prev = stash->lastUnit;
- stash->lastUnit = x;
- }
- return x;
- }
- /* Return a newly allocated dwarf1_func. It must be cleared and
- attached into 'aUnit' at 'aUnit->func_list'. */
- static struct dwarf1_func *
- alloc_dwarf1_func (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
- {
- size_t amt = sizeof (struct dwarf1_func);
- struct dwarf1_func* x = (struct dwarf1_func *) bfd_zalloc (stash->abfd, amt);
- if (x)
- {
- x->prev = aUnit->func_list;
- aUnit->func_list = x;
- }
- return x;
- }
- /* parse_die - parse a Dwarf1 die.
- Parse the die starting at 'aDiePtr' into 'aDieInfo'.
- 'abfd' must be the bfd from which the section that 'aDiePtr'
- points to was pulled from.
- Return FALSE if the die is invalidly formatted; TRUE otherwise. */
- static bool
- parse_die (bfd * abfd,
- struct die_info * aDieInfo,
- bfd_byte * aDiePtr,
- bfd_byte * aDiePtrEnd)
- {
- bfd_byte *this_die = aDiePtr;
- bfd_byte *xptr = this_die;
- memset (aDieInfo, 0, sizeof (* aDieInfo));
- /* First comes the length. */
- if (xptr + 4 > aDiePtrEnd)
- return false;
- aDieInfo->length = bfd_get_32 (abfd, xptr);
- xptr += 4;
- if (aDieInfo->length <= 4
- || (size_t) (aDiePtrEnd - this_die) < aDieInfo->length)
- return false;
- aDiePtrEnd = this_die + aDieInfo->length;
- if (aDieInfo->length < 6)
- {
- /* Just padding bytes. */
- aDieInfo->tag = TAG_padding;
- return true;
- }
- /* Then the tag. */
- if (xptr + 2 > aDiePtrEnd)
- return false;
- aDieInfo->tag = bfd_get_16 (abfd, xptr);
- xptr += 2;
- /* Then the attributes. */
- while (xptr + 2 <= aDiePtrEnd)
- {
- unsigned int block_len;
- unsigned short attr;
- /* Parse the attribute based on its form. This section
- must handle all dwarf1 forms, but need only handle the
- actual attributes that we care about. */
- attr = bfd_get_16 (abfd, xptr);
- xptr += 2;
- switch (FORM_FROM_ATTR (attr))
- {
- case FORM_DATA2:
- xptr += 2;
- break;
- case FORM_DATA4:
- case FORM_REF:
- if (xptr + 4 <= aDiePtrEnd)
- {
- if (attr == AT_sibling)
- aDieInfo->sibling = bfd_get_32 (abfd, xptr);
- else if (attr == AT_stmt_list)
- {
- aDieInfo->stmt_list_offset = bfd_get_32 (abfd, xptr);
- aDieInfo->has_stmt_list = 1;
- }
- }
- xptr += 4;
- break;
- case FORM_DATA8:
- xptr += 8;
- break;
- case FORM_ADDR:
- if (xptr + 4 <= aDiePtrEnd)
- {
- if (attr == AT_low_pc)
- aDieInfo->low_pc = bfd_get_32 (abfd, xptr);
- else if (attr == AT_high_pc)
- aDieInfo->high_pc = bfd_get_32 (abfd, xptr);
- }
- xptr += 4;
- break;
- case FORM_BLOCK2:
- if (xptr + 2 <= aDiePtrEnd)
- {
- block_len = bfd_get_16 (abfd, xptr);
- if ((size_t) (aDiePtrEnd - xptr) < block_len)
- return false;
- xptr += block_len;
- }
- xptr += 2;
- break;
- case FORM_BLOCK4:
- if (xptr + 4 <= aDiePtrEnd)
- {
- block_len = bfd_get_32 (abfd, xptr);
- if ((size_t) (aDiePtrEnd - xptr) < block_len)
- return false;
- xptr += block_len;
- }
- xptr += 4;
- break;
- case FORM_STRING:
- if (attr == AT_name)
- aDieInfo->name = (char *) xptr;
- xptr += strnlen ((char *) xptr, aDiePtrEnd - xptr) + 1;
- break;
- }
- }
- return true;
- }
- /* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset'
- into 'aUnit->linenumber_table'. Return FALSE if an error
- occurs; TRUE otherwise. */
- static bool
- parse_line_table (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
- {
- bfd_byte *xptr;
- /* Load the ".line" section from the bfd if we haven't already. */
- if (stash->line_section == 0)
- {
- asection *msec;
- bfd_size_type size;
- msec = bfd_get_section_by_name (stash->abfd, ".line");
- if (! msec)
- return false;
- size = msec->rawsize ? msec->rawsize : msec->size;
- stash->line_section
- = bfd_simple_get_relocated_section_contents
- (stash->abfd, msec, NULL, stash->syms);
- if (! stash->line_section)
- return false;
- stash->line_section_end = stash->line_section + size;
- }
- xptr = stash->line_section + aUnit->stmt_list_offset;
- if (xptr + 8 <= stash->line_section_end)
- {
- unsigned long eachLine;
- bfd_byte *tblend;
- unsigned long base;
- bfd_size_type amt;
- /* First comes the length. */
- tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr;
- xptr += 4;
- /* Then the base address for each address in the table. */
- base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
- xptr += 4;
- /* How many line entrys?
- 10 = 4 (line number) + 2 (pos in line) + 4 (address in line). */
- aUnit->line_count = (tblend - xptr) / 10;
- /* Allocate an array for the entries. */
- amt = sizeof (struct linenumber) * aUnit->line_count;
- aUnit->linenumber_table = (struct linenumber *) bfd_alloc (stash->abfd,
- amt);
- if (!aUnit->linenumber_table)
- return false;
- for (eachLine = 0; eachLine < aUnit->line_count; eachLine++)
- {
- if (xptr + 10 > stash->line_section_end)
- {
- aUnit->line_count = eachLine;
- break;
- }
- /* A line number. */
- aUnit->linenumber_table[eachLine].linenumber
- = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
- xptr += 4;
- /* Skip the position within the line. */
- xptr += 2;
- /* And finally the address. */
- aUnit->linenumber_table[eachLine].addr
- = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
- xptr += 4;
- }
- }
- return true;
- }
- /* Parse each function die in a compilation unit 'aUnit'.
- The first child die of 'aUnit' should be in 'aUnit->first_child',
- the result is placed in 'aUnit->func_list'.
- Return FALSE if error; TRUE otherwise. */
- static bool
- parse_functions_in_unit (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
- {
- bfd_byte *eachDie;
- if (aUnit->first_child)
- for (eachDie = aUnit->first_child;
- eachDie < stash->debug_section_end;
- )
- {
- struct die_info eachDieInfo;
- if (! parse_die (stash->abfd, &eachDieInfo, eachDie,
- stash->debug_section_end))
- return false;
- if (eachDieInfo.tag == TAG_global_subroutine
- || eachDieInfo.tag == TAG_subroutine
- || eachDieInfo.tag == TAG_inlined_subroutine
- || eachDieInfo.tag == TAG_entry_point)
- {
- struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit);
- if (!aFunc)
- return false;
- aFunc->name = eachDieInfo.name;
- aFunc->low_pc = eachDieInfo.low_pc;
- aFunc->high_pc = eachDieInfo.high_pc;
- }
- /* Move to next sibling, if none, end loop */
- if (eachDieInfo.sibling)
- eachDie = stash->debug_section + eachDieInfo.sibling;
- else
- break;
- }
- return true;
- }
- /* Find the nearest line to 'addr' in 'aUnit'.
- Return whether we found the line (or a function) without error. */
- static bool
- dwarf1_unit_find_nearest_line (struct dwarf1_debug* stash,
- struct dwarf1_unit* aUnit,
- unsigned long addr,
- const char **filename_ptr,
- const char **functionname_ptr,
- unsigned int *linenumber_ptr)
- {
- int line_p = false;
- int func_p = false;
- if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
- {
- if (aUnit->has_stmt_list)
- {
- unsigned long i;
- struct dwarf1_func* eachFunc;
- if (! aUnit->linenumber_table)
- {
- if (! parse_line_table (stash, aUnit))
- return false;
- }
- if (! aUnit->func_list)
- {
- if (! parse_functions_in_unit (stash, aUnit))
- return false;
- }
- for (i = 0; i < aUnit->line_count; i++)
- {
- if (aUnit->linenumber_table[i].addr <= addr
- && addr < aUnit->linenumber_table[i+1].addr)
- {
- *filename_ptr = aUnit->name;
- *linenumber_ptr = aUnit->linenumber_table[i].linenumber;
- line_p = true;
- break;
- }
- }
- for (eachFunc = aUnit->func_list;
- eachFunc;
- eachFunc = eachFunc->prev)
- {
- if (eachFunc->low_pc <= addr
- && addr < eachFunc->high_pc)
- {
- *functionname_ptr = eachFunc->name;
- func_p = true;
- break;
- }
- }
- }
- }
- return line_p || func_p;
- }
- /* The DWARF 1 version of find_nearest line.
- Return TRUE if the line is found without error. */
- bool
- _bfd_dwarf1_find_nearest_line (bfd *abfd,
- asymbol **symbols,
- asection *section,
- bfd_vma offset,
- const char **filename_ptr,
- const char **functionname_ptr,
- unsigned int *linenumber_ptr)
- {
- struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info;
- struct dwarf1_unit* eachUnit;
- /* What address are we looking for? */
- unsigned long addr = (unsigned long)(offset + section->vma);
- *filename_ptr = NULL;
- *functionname_ptr = NULL;
- *linenumber_ptr = 0;
- if (! stash)
- {
- asection *msec;
- bfd_size_type size = sizeof (struct dwarf1_debug);
- stash = elf_tdata (abfd)->dwarf1_find_line_info
- = (struct dwarf1_debug *) bfd_zalloc (abfd, size);
- if (! stash)
- return false;
- msec = bfd_get_section_by_name (abfd, ".debug");
- if (! msec)
- /* No dwarf1 info. Note that at this point the stash
- has been allocated, but contains zeros, this lets
- future calls to this function fail quicker. */
- return false;
- size = msec->rawsize ? msec->rawsize : msec->size;
- stash->debug_section
- = bfd_simple_get_relocated_section_contents (abfd, msec, NULL,
- symbols);
- if (! stash->debug_section)
- return false;
- stash->debug_section_end = stash->debug_section + size;
- stash->currentDie = stash->debug_section;
- stash->abfd = abfd;
- stash->syms = symbols;
- }
- /* A null debug_section indicates that there was no dwarf1 info
- or that an error occured while setting up the stash. */
- if (! stash->debug_section)
- return false;
- /* Look at the previously parsed units to see if any contain
- the addr. */
- for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev)
- if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc)
- return dwarf1_unit_find_nearest_line (stash, eachUnit, addr,
- filename_ptr,
- functionname_ptr,
- linenumber_ptr);
- while (stash->currentDie < stash->debug_section_end)
- {
- struct die_info aDieInfo;
- if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie,
- stash->debug_section_end))
- return false;
- if (aDieInfo.tag == TAG_compile_unit)
- {
- struct dwarf1_unit* aUnit
- = alloc_dwarf1_unit (stash);
- if (!aUnit)
- return false;
- aUnit->name = aDieInfo.name;
- aUnit->low_pc = aDieInfo.low_pc;
- aUnit->high_pc = aDieInfo.high_pc;
- aUnit->has_stmt_list = aDieInfo.has_stmt_list;
- aUnit->stmt_list_offset = aDieInfo.stmt_list_offset;
- /* A die has a child if it's followed by a die that is
- not it's sibling. */
- if (aDieInfo.sibling
- && stash->currentDie + aDieInfo.length
- < stash->debug_section_end
- && stash->currentDie + aDieInfo.length
- != stash->debug_section + aDieInfo.sibling)
- aUnit->first_child = stash->currentDie + aDieInfo.length;
- else
- aUnit->first_child = 0;
- if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
- return dwarf1_unit_find_nearest_line (stash, aUnit, addr,
- filename_ptr,
- functionname_ptr,
- linenumber_ptr);
- }
- if (aDieInfo.sibling != 0)
- stash->currentDie = stash->debug_section + aDieInfo.sibling;
- else
- stash->currentDie += aDieInfo.length;
- }
- return false;
- }
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