xref: /external/elfutils/libdw/libdwP.h

/* Internal definitions for libdwarf.
   Copyright (C) 2002-2011, 2013, 2014 Red Hat, Inc.
   This file is part of elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 2002.

   This file is free software; you can redistribute it and/or modify
   it under the terms of either

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at
       your option) any later version

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at
       your option) any later version

   or both in parallel, as here.

   elfutils 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 copies of the GNU General Public License and
   the GNU Lesser General Public License along with this program.  If
   not, see <http://www.gnu.org/licenses/>.  */

#ifndef _LIBDWP_H
#define _LIBDWP_H 1

#include <libintl.h>
#include <stdbool.h>

#include <libdw.h>
#include <dwarf.h>


/* gettext helper macros.  */
#define _(Str) dgettext ("elfutils", Str)


/* Known location expressions already decoded.  */
struct loc_s
{
  void *addr;
  Dwarf_Op *loc;
  size_t nloc;
};

/* Known DW_OP_implicit_value blocks already decoded.
   This overlaps struct loc_s exactly, but only the
   first member really has to match.  */
struct loc_block_s
{
  void *addr;
  unsigned char *data;
  size_t length;
};

/* Valid indeces for the section data.  */
enum
  {
    IDX_debug_info = 0,
    IDX_debug_types,
    IDX_debug_abbrev,
    IDX_debug_aranges,
    IDX_debug_line,
    IDX_debug_frame,
    IDX_debug_loc,
    IDX_debug_pubnames,
    IDX_debug_str,
    IDX_debug_macinfo,
    IDX_debug_macro,
    IDX_debug_ranges,
    IDX_gnu_debugaltlink,
    IDX_last
  };


/* Error values.  */
enum
{
  DWARF_E_NOERROR = 0,
  DWARF_E_UNKNOWN_ERROR,
  DWARF_E_INVALID_ACCESS,
  DWARF_E_NO_REGFILE,
  DWARF_E_IO_ERROR,
  DWARF_E_INVALID_ELF,
  DWARF_E_NO_DWARF,
  DWARF_E_NOELF,
  DWARF_E_GETEHDR_ERROR,
  DWARF_E_NOMEM,
  DWARF_E_UNIMPL,
  DWARF_E_INVALID_CMD,
  DWARF_E_INVALID_VERSION,
  DWARF_E_INVALID_FILE,
  DWARF_E_NO_ENTRY,
  DWARF_E_INVALID_DWARF,
  DWARF_E_NO_STRING,
  DWARF_E_NO_ADDR,
  DWARF_E_NO_CONSTANT,
  DWARF_E_NO_REFERENCE,
  DWARF_E_INVALID_REFERENCE,
  DWARF_E_NO_DEBUG_LINE,
  DWARF_E_INVALID_DEBUG_LINE,
  DWARF_E_TOO_BIG,
  DWARF_E_VERSION,
  DWARF_E_INVALID_DIR_IDX,
  DWARF_E_ADDR_OUTOFRANGE,
  DWARF_E_NO_LOCLIST,
  DWARF_E_NO_BLOCK,
  DWARF_E_INVALID_LINE_IDX,
  DWARF_E_INVALID_ARANGE_IDX,
  DWARF_E_NO_MATCH,
  DWARF_E_NO_FLAG,
  DWARF_E_INVALID_OFFSET,
  DWARF_E_NO_DEBUG_RANGES,
  DWARF_E_INVALID_CFI,
  DWARF_E_NO_ALT_DEBUGLINK
};


#include "dwarf_sig8_hash.h"

/* This is the structure representing the debugging state.  */
struct Dwarf
{
  /* The underlying ELF file.  */
  Elf *elf;

  /* dwz alternate DWARF file.  */
  Dwarf *alt_dwarf;

  /* The section data.  */
  Elf_Data *sectiondata[IDX_last];

#if USE_ZLIB
  /* The 1 << N bit is set if sectiondata[N] is malloc'd decompressed data.  */
  unsigned int sectiondata_gzip_mask:IDX_last;
#endif

  /* True if the file has a byte order different from the host.  */
  bool other_byte_order;

  /* If true, we allocated the ELF descriptor ourselves.  */
  bool free_elf;

  /* Information for traversing the .debug_pubnames section.  This is
     an array and separately allocated with malloc.  */
  struct pubnames_s
  {
    Dwarf_Off cu_offset;
    Dwarf_Off set_start;
    unsigned int cu_header_size;
    int address_len;
  } *pubnames_sets;
  size_t pubnames_nsets;

  /* Search tree for the CUs.  */
  void *cu_tree;
  Dwarf_Off next_cu_offset;

  /* Search tree and sig8 hash table for .debug_types type units.  */
  void *tu_tree;
  Dwarf_Off next_tu_offset;
  Dwarf_Sig8_Hash sig8_hash;

  /* Address ranges.  */
  Dwarf_Aranges *aranges;

  /* Cached info from the CFI section.  */
  struct Dwarf_CFI_s *cfi;

  /* Internal memory handling.  This is basically a simplified
     reimplementation of obstacks.  Unfortunately the standard obstack
     implementation is not usable in libraries.  */
  struct libdw_memblock
  {
    size_t size;
    size_t remaining;
    struct libdw_memblock *prev;
    char mem[0];
  } *mem_tail;

  /* Default size of allocated memory blocks.  */
  size_t mem_default_size;

  /* Registered OOM handler.  */
  Dwarf_OOM oom_handler;
};


/* Abbreviation representation.  */
struct Dwarf_Abbrev
{
  Dwarf_Off offset;
  unsigned char *attrp;
  unsigned int attrcnt;
  unsigned int code;
  unsigned int tag;
  bool has_children;
};

#include "dwarf_abbrev_hash.h"


/* Files in line information records.  */
struct Dwarf_Files_s
  {
    struct Dwarf_CU *cu;
    unsigned int ndirs;
    unsigned int nfiles;
    struct Dwarf_Fileinfo_s
    {
      char *name;
      Dwarf_Word mtime;
      Dwarf_Word length;
    } info[0];
    /* nfiles of those, followed by char *[ndirs].  */
  };
typedef struct Dwarf_Fileinfo_s Dwarf_Fileinfo;


/* Representation of a row in the line table.  */

struct Dwarf_Line_s
{
  Dwarf_Files *files;

  Dwarf_Addr addr;
  unsigned int file;
  int line;
  unsigned short int column;
  unsigned int is_stmt:1;
  unsigned int basic_block:1;
  unsigned int end_sequence:1;
  unsigned int prologue_end:1;
  unsigned int epilogue_begin:1;
  /* The remaining bit fields are not flags, but hold values presumed to be
     small.  All the flags and other bit fields should add up to 48 bits
     to give the whole struct a nice round size.  */
  unsigned int op_index:8;
  unsigned int isa:8;
  unsigned int discriminator:24;
};

struct Dwarf_Lines_s
{
  size_t nlines;
  struct Dwarf_Line_s info[0];
};

/* Representation of address ranges.  */
struct Dwarf_Aranges_s
{
  Dwarf *dbg;
  size_t naranges;

  struct Dwarf_Arange_s
  {
    Dwarf_Addr addr;
    Dwarf_Word length;
    Dwarf_Off offset;
  } info[0];
};


/* CU representation.  */
struct Dwarf_CU
{
  Dwarf *dbg;
  Dwarf_Off start;
  Dwarf_Off end;
  uint8_t address_size;
  uint8_t offset_size;
  uint16_t version;

  /* Zero if this is a normal CU.  Nonzero if it is a type unit.  */
  size_t type_offset;
  uint64_t type_sig8;

  /* Hash table for the abbreviations.  */
  Dwarf_Abbrev_Hash abbrev_hash;
  /* Offset of the first abbreviation.  */
  size_t orig_abbrev_offset;
  /* Offset past last read abbreviation.  */
  size_t last_abbrev_offset;

  /* The srcline information.  */
  Dwarf_Lines *lines;

  /* The source file information.  */
  Dwarf_Files *files;

  /* Known location lists.  */
  void *locs;
};

/* Compute the offset of a CU's first DIE from its offset.  This
   is either:
        LEN       VER     OFFSET    ADDR
      4-bytes + 2-bytes + 4-bytes + 1-byte  for 32-bit dwarf
     12-bytes + 2-bytes + 8-bytes + 1-byte  for 64-bit dwarf
   or in .debug_types, 			     SIGNATURE TYPE-OFFSET
      4-bytes + 2-bytes + 4-bytes + 1-byte + 8-bytes + 4-bytes  for 32-bit
     12-bytes + 2-bytes + 8-bytes + 1-byte + 8-bytes + 8-bytes  for 64-bit

   Note the trick in the computation.  If the offset_size is 4
   the '- 4' term changes the '3 *' into a '2 *'.  If the
   offset_size is 8 it accounts for the 4-byte escape value
   used at the start of the length.  */
#define DIE_OFFSET_FROM_CU_OFFSET(cu_offset, offset_size, type_unit)	\
  ((type_unit) ? ((cu_offset) + 4 * (offset_size) - 4 + 3 + 8)		\
   : ((cu_offset) + 3 * (offset_size) - 4 + 3))

#define CUDIE(fromcu)							      \
  ((Dwarf_Die)								      \
   {									      \
     .cu = (fromcu),							      \
     .addr = ((char *) cu_data (fromcu)->d_buf				      \
	      + DIE_OFFSET_FROM_CU_OFFSET ((fromcu)->start,		      \
					   (fromcu)->offset_size,	      \
					   (fromcu)->type_offset != 0))	      \
   })									      \


/* Macro information.  */
struct Dwarf_Macro_s
{
  unsigned int opcode;
  Dwarf_Word param1;
  union
  {
    Dwarf_Word u;
    const char *s;
  } param2;
};


/* We have to include the file at this point because the inline
   functions access internals of the Dwarf structure.  */
#include "memory-access.h"


/* Set error value.  */
extern void __libdw_seterrno (int value) internal_function;


/* Memory handling, the easy parts.  This macro does not do any locking.  */
#define libdw_alloc(dbg, type, tsize, cnt) \
  ({ struct libdw_memblock *_tail = (dbg)->mem_tail;			      \
     size_t _required = (tsize) * (cnt);				      \
     type *_result = (type *) (_tail->mem + (_tail->size - _tail->remaining));\
     size_t _padding = ((__alignof (type)				      \
			 - ((uintptr_t) _result & (__alignof (type) - 1)))    \
			& (__alignof (type) - 1));			      \
     if (unlikely (_tail->remaining < _required + _padding))		      \
       _result = (type *) __libdw_allocate (dbg, _required, __alignof (type));\
     else								      \
       {								      \
	 _required += _padding;						      \
	 _result = (type *) ((char *) _result + _padding);		      \
	 _tail->remaining -= _required;					      \
       }								      \
     _result; })

#define libdw_typed_alloc(dbg, type) \
  libdw_alloc (dbg, type, sizeof (type), 1)

/* Callback to allocate more.  */
extern void *__libdw_allocate (Dwarf *dbg, size_t minsize, size_t align)
     __attribute__ ((__malloc__)) __nonnull_attribute__ (1);

/* Default OOM handler.  */
extern void __libdw_oom (void) __attribute ((noreturn, visibility ("hidden")));

#if USE_ZLIB
extern void __libdw_free_zdata (Dwarf *dwarf) internal_function;
#else
# define __libdw_free_zdata(dwarf)	((void) (dwarf))
#endif

/* Allocate the internal data for a unit not seen before.  */
extern struct Dwarf_CU *__libdw_intern_next_unit (Dwarf *dbg, bool debug_types)
     __nonnull_attribute__ (1) internal_function;

/* Find CU for given offset.  */
extern struct Dwarf_CU *__libdw_findcu (Dwarf *dbg, Dwarf_Off offset, bool tu)
     __nonnull_attribute__ (1) internal_function;

/* Return tag of given DIE.  */
extern Dwarf_Abbrev *__libdw_findabbrev (struct Dwarf_CU *cu,
					 unsigned int code)
     __nonnull_attribute__ (1) internal_function;

/* Get abbreviation at given offset.  */
extern Dwarf_Abbrev *__libdw_getabbrev (Dwarf *dbg, struct Dwarf_CU *cu,
					Dwarf_Off offset, size_t *lengthp,
					Dwarf_Abbrev *result)
     __nonnull_attribute__ (1) internal_function;

/* Helper functions for form handling.  */
extern size_t __libdw_form_val_compute_len (Dwarf *dbg, struct Dwarf_CU *cu,
					    unsigned int form,
					    const unsigned char *valp)
     __nonnull_attribute__ (1, 2, 4) internal_function;

/* Find the length of a form attribute.  */
static inline size_t
__nonnull_attribute__ (1, 2, 4)
__libdw_form_val_len (Dwarf *dbg, struct Dwarf_CU *cu,
		      unsigned int form, const unsigned char *valp)
{
  /* Small lookup table of forms with fixed lengths.  Absent indexes are
     initialized 0, so any truly desired 0 is set to 0x80 and masked.  */
  static const uint8_t form_lengths[] =
    {
      [DW_FORM_flag_present] = 0x80,
      [DW_FORM_data1] = 1, [DW_FORM_ref1] = 1, [DW_FORM_flag] = 1,
      [DW_FORM_data2] = 2, [DW_FORM_ref2] = 2,
      [DW_FORM_data4] = 4, [DW_FORM_ref4] = 4,
      [DW_FORM_data8] = 8, [DW_FORM_ref8] = 8, [DW_FORM_ref_sig8] = 8,
    };

  /* Return immediately for forms with fixed lengths.  */
  if (form < sizeof form_lengths / sizeof form_lengths[0])
    {
      uint8_t len = form_lengths[form];
      if (len != 0)
	return len & 0x7f; /* Mask to allow 0x80 -> 0.  */
    }

  /* Other forms require some computation.  */
  return __libdw_form_val_compute_len (dbg, cu, form, valp);
}

/* Helper function for DW_FORM_ref* handling.  */
extern int __libdw_formref (Dwarf_Attribute *attr, Dwarf_Off *return_offset)
     __nonnull_attribute__ (1, 2) internal_function;


/* Helper function to locate attribute.  */
extern unsigned char *__libdw_find_attr (Dwarf_Die *die,
					 unsigned int search_name,
					 unsigned int *codep,
					 unsigned int *formp)
     __nonnull_attribute__ (1) internal_function;

/* Helper function to access integer attribute.  */
extern int __libdw_attr_intval (Dwarf_Die *die, int *valp, int attval)
     __nonnull_attribute__ (1, 2) internal_function;

/* Helper function to walk scopes.  */
struct Dwarf_Die_Chain
{
  Dwarf_Die die;
  struct Dwarf_Die_Chain *parent;
  bool prune;			/* The PREVISIT function can set this.  */
};
extern int __libdw_visit_scopes (unsigned int depth,
				 struct Dwarf_Die_Chain *root,
				 int (*previsit) (unsigned int depth,
						  struct Dwarf_Die_Chain *,
						  void *arg),
				 int (*postvisit) (unsigned int depth,
						   struct Dwarf_Die_Chain *,
						   void *arg),
				 void *arg)
  __nonnull_attribute__ (2, 3) internal_function;

/* Parse a DWARF Dwarf_Block into an array of Dwarf_Op's,
   and cache the result (via tsearch).  */
extern int __libdw_intern_expression (Dwarf *dbg,
				      bool other_byte_order,
				      unsigned int address_size,
				      unsigned int ref_size,
				      void **cache, const Dwarf_Block *block,
				      bool cfap, bool valuep,
				      Dwarf_Op **llbuf, size_t *listlen,
				      int sec_index)
  __nonnull_attribute__ (5, 6, 9, 10) internal_function;

extern Dwarf_Die *__libdw_offdie (Dwarf *dbg, Dwarf_Off offset,
				  Dwarf_Die *result, bool debug_types)
  internal_function;


/* Return error code of last failing function call.  This value is kept
   separately for each thread.  */
extern int __dwarf_errno_internal (void);


/* Reader hooks.  */

/* Relocation hooks return -1 on error (in that case the error code
   must already have been set), 0 if there is no relocation and 1 if a
   relocation was present.*/

static inline int
__libdw_relocate_address (Dwarf *dbg __attribute__ ((unused)),
			  int sec_index __attribute__ ((unused)),
			  const void *addr __attribute__ ((unused)),
			  int width __attribute__ ((unused)),
			  Dwarf_Addr *val __attribute__ ((unused)))
{
  return 0;
}

static inline int
__libdw_relocate_offset (Dwarf *dbg __attribute__ ((unused)),
			 int sec_index __attribute__ ((unused)),
			 const void *addr __attribute__ ((unused)),
			 int width __attribute__ ((unused)),
			 Dwarf_Off *val __attribute__ ((unused)))
{
  return 0;
}

static inline Elf_Data *
__libdw_checked_get_data (Dwarf *dbg, int sec_index)
{
  Elf_Data *data = dbg->sectiondata[sec_index];
  if (unlikely (data == NULL)
      || unlikely (data->d_buf == NULL))
    {
      __libdw_seterrno (DWARF_E_INVALID_DWARF);
      return NULL;
    }
  return data;
}

static inline int
__libdw_offset_in_section (Dwarf *dbg, int sec_index,
			   Dwarf_Off offset, size_t size)
{
  Elf_Data *data = __libdw_checked_get_data (dbg, sec_index);
  if (data == NULL)
    return -1;
  if (unlikely (offset > data->d_size)
      || unlikely (data->d_size - offset < size))
    {
      __libdw_seterrno (DWARF_E_INVALID_OFFSET);
      return -1;
    }

  return 0;
}

static inline bool
__libdw_in_section (Dwarf *dbg, int sec_index,
		    const void *addr, size_t size)
{
  Elf_Data *data = __libdw_checked_get_data (dbg, sec_index);
  if (data == NULL)
    return false;
  if (unlikely (addr < data->d_buf)
      || unlikely (data->d_size - (addr - data->d_buf) < size))
    {
      __libdw_seterrno (DWARF_E_INVALID_OFFSET);
      return false;
    }

  return true;
}

#define READ_AND_RELOCATE(RELOC_HOOK, VAL)				\
  ({									\
    if (!__libdw_in_section (dbg, sec_index, addr, width))		\
      return -1;							\
									\
    const unsigned char *orig_addr = addr;				\
    if (width == 4)							\
      VAL = read_4ubyte_unaligned_inc (dbg, addr);			\
    else								\
      VAL = read_8ubyte_unaligned_inc (dbg, addr);			\
									\
    int status = RELOC_HOOK (dbg, sec_index, orig_addr, width, &VAL);	\
    if (status < 0)							\
      return status;							\
    status > 0;								\
   })

static inline int
__libdw_read_address_inc (Dwarf *dbg,
			  int sec_index, const unsigned char **addrp,
			  int width, Dwarf_Addr *ret)
{
  const unsigned char *addr = *addrp;
  READ_AND_RELOCATE (__libdw_relocate_address, (*ret));
  *addrp = addr;
  return 0;
}

static inline int
__libdw_read_address (Dwarf *dbg,
		      int sec_index, const unsigned char *addr,
		      int width, Dwarf_Addr *ret)
{
  READ_AND_RELOCATE (__libdw_relocate_address, (*ret));
  return 0;
}

static inline int
__libdw_read_offset_inc (Dwarf *dbg,
			 int sec_index, const unsigned char **addrp,
			 int width, Dwarf_Off *ret, int sec_ret,
			 size_t size)
{
  const unsigned char *addr = *addrp;
  READ_AND_RELOCATE (__libdw_relocate_offset, (*ret));
  *addrp = addr;
  return __libdw_offset_in_section (dbg, sec_ret, *ret, size);
}

static inline int
__libdw_read_offset (Dwarf *dbg, Dwarf *dbg_ret,
		     int sec_index, const unsigned char *addr,
		     int width, Dwarf_Off *ret, int sec_ret,
		     size_t size)
{
  READ_AND_RELOCATE (__libdw_relocate_offset, (*ret));
  return __libdw_offset_in_section (dbg_ret, sec_ret, *ret, size);
}

static inline size_t
cu_sec_idx (struct Dwarf_CU *cu)
{
  return cu->type_offset == 0 ? IDX_debug_info : IDX_debug_types;
}

static inline Elf_Data *
cu_data (struct Dwarf_CU *cu)
{
  return cu->dbg->sectiondata[cu_sec_idx (cu)];
}

/* Read up begin/end pair and increment read pointer.
    - If it's normal range record, set up *BEGINP and *ENDP and return 0.
    - If it's base address selection record, set up *BASEP and return 1.
    - If it's end of rangelist, don't set anything and return 2
    - If an error occurs, don't set anything and return <0.  */
int __libdw_read_begin_end_pair_inc (Dwarf *dbg, int sec_index,
				     unsigned char **addr, int width,
				     Dwarf_Addr *beginp, Dwarf_Addr *endp,
				     Dwarf_Addr *basep)
  internal_function;

unsigned char * __libdw_formptr (Dwarf_Attribute *attr, int sec_index,
				 int err_nodata, unsigned char **endpp,
				 Dwarf_Off *offsetp)
  internal_function;

#ifdef ENABLE_DWZ
/* Checks that the build_id of the underlying Elf matches the expected.
   Returns zero on match, -1 on error or no build_id found or 1 when
   build_id doesn't match.  */
int __check_build_id (Dwarf *dw, const uint8_t *build_id, const size_t id_len)
  internal_function;
#endif /* ENABLE_DWZ */

/* Fills in the given attribute to point at an empty location expression.  */
void __libdw_empty_loc_attr (Dwarf_Attribute *attr, struct Dwarf_CU *cu)
  internal_function;


/* Aliases to avoid PLTs.  */
INTDECL (dwarf_aggregate_size)
INTDECL (dwarf_attr)
INTDECL (dwarf_attr_integrate)
INTDECL (dwarf_begin)
INTDECL (dwarf_begin_elf)
INTDECL (dwarf_child)
INTDECL (dwarf_dieoffset)
INTDECL (dwarf_diename)
INTDECL (dwarf_end)
INTDECL (dwarf_entrypc)
INTDECL (dwarf_errmsg)
INTDECL (dwarf_formaddr)
INTDECL (dwarf_formblock)
INTDECL (dwarf_formref_die)
INTDECL (dwarf_formsdata)
INTDECL (dwarf_formstring)
INTDECL (dwarf_formudata)
INTDECL (dwarf_getalt)
INTDECL (dwarf_getarange_addr)
INTDECL (dwarf_getarangeinfo)
INTDECL (dwarf_getaranges)
INTDECL (dwarf_getlocation_die)
INTDECL (dwarf_getsrcfiles)
INTDECL (dwarf_getsrclines)
INTDECL (dwarf_hasattr)
INTDECL (dwarf_haschildren)
INTDECL (dwarf_haspc)
INTDECL (dwarf_highpc)
INTDECL (dwarf_lowpc)
INTDECL (dwarf_nextcu)
INTDECL (dwarf_next_unit)
INTDECL (dwarf_offdie)
INTDECL (dwarf_ranges)
INTDECL (dwarf_setalt)
INTDECL (dwarf_siblingof)
INTDECL (dwarf_srclang)
INTDECL (dwarf_tag)

#endif	/* libdwP.h */