dwarf2dbg.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 1,313 行 · 第 1/3 页

/* dwarf2dbg.c - DWARF2 debug support
   Copyright 1999, 2000, 2001 Free Software Foundation, Inc.
   Contributed by David Mosberger-Tang <[e-mail]>

   This file is part of GAS, the GNU Assembler.

   GAS 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 2, or (at your option)
   any later version.

   GAS 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 GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 59 Temple Place - Suite 330, Boston, MA
   02111-1307, USA.  */

/* Logical line numbers can be controlled by the compiler via the
   following two directives:

	.file FILENO "file.c"
	.loc  FILENO LINENO [COLUMN]

   FILENO is the filenumber.  */

#include "ansidecl.h"
#include "as.h"

#ifdef HAVE_LIMITS_H
#include <limits.h>
#else
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifndef INT_MAX
#define INT_MAX (int) (((unsigned) (-1)) >> 1)
#endif
#endif

#ifdef BFD_ASSEMBLER

#include "dwarf2dbg.h"
#include "subsegs.h"

#include "elf/dwarf2.h"

/* Since we can't generate the prolog until the body is complete, we
   use three different subsegments for .debug_line: one holding the
   prolog, one for the directory and filename info, and one for the
   body ("statement program").  */
#define DL_PROLOG	0
#define DL_FILES	1
#define DL_BODY		2

/* First special line opcde - leave room for the standard opcodes.
   Note: If you want to change this, you'll have to update the
   "standard_opcode_lengths" table that is emitted below in
   dwarf2_finish().  */
#define DWARF2_LINE_OPCODE_BASE		10

#ifndef DWARF2_LINE_BASE
  /* Minimum line offset in a special line info. opcode.  This value
     was chosen to give a reasonable range of values.  */
# define DWARF2_LINE_BASE		-5
#endif

/* Range of line offsets in a special line info. opcode.  */
#ifndef DWARF2_LINE_RANGE
# define DWARF2_LINE_RANGE		14
#endif

#ifndef DWARF2_LINE_MIN_INSN_LENGTH
  /* Define the architecture-dependent minimum instruction length (in
     bytes).  This value should be rather too small than too big.  */
# define DWARF2_LINE_MIN_INSN_LENGTH	1
#endif

/* Flag that indicates the initial value of the is_stmt_start flag.
   In the present implementation, we do not mark any lines as
   the beginning of a source statement, because that information
   is not made available by the GCC front-end.  */
#define	DWARF2_LINE_DEFAULT_IS_STMT	1

/* Given a special op, return the line skip amount.  */
#define SPECIAL_LINE(op) \
	(((op) - DWARF2_LINE_OPCODE_BASE)%DWARF2_LINE_RANGE + DWARF2_LINE_BASE)

/* Given a special op, return the address skip amount (in units of
   DWARF2_LINE_MIN_INSN_LENGTH.  */
#define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)

/* The maximum address skip amount that can be encoded with a special op.  */
#define MAX_SPECIAL_ADDR_DELTA		SPECIAL_ADDR(255)

struct line_entry {
  struct line_entry *next;
  fragS *frag;
  addressT frag_ofs;
  struct dwarf2_line_info loc;
};

struct line_subseg {
  struct line_subseg *next;
  subsegT subseg;
  struct line_entry *head;
  struct line_entry **ptail;
};

struct line_seg {
  struct line_seg *next;
  segT seg;
  struct line_subseg *head;
  symbolS *text_start;
  symbolS *text_end;
};

/* Collects data for all line table entries during assembly.  */
static struct line_seg *all_segs;

struct file_entry {
  char *filename;
  unsigned int dir;
};

/* Table of files used by .debug_line.  */
static struct file_entry *files;
static unsigned int files_in_use;
static unsigned int files_allocated;

/* True when we've seen a .loc directive recently.  Used to avoid
   doing work when there's nothing to do.  */
static boolean loc_directive_seen;

/* Current location as indicated by the most recent .loc directive.  */
static struct dwarf2_line_info current;

/* Fake label name.  */
static char const fake_label_name[] = ".L0\001";

/* The size of an address on the target.  */
static unsigned int sizeof_address;

static struct line_subseg *get_line_subseg PARAMS ((segT, subsegT));
static unsigned int get_filenum PARAMS ((const char *));
static struct frag *first_frag_for_seg PARAMS ((segT));
static struct frag *last_frag_for_seg PARAMS ((segT));
static void out_byte PARAMS ((int));
static void out_opcode PARAMS ((int));
static void out_two PARAMS ((int));
static void out_four PARAMS ((int));
static void out_abbrev PARAMS ((int, int));
static void out_uleb128 PARAMS ((addressT));
static symbolS *symbol_new_now PARAMS ((void));
static void set_symbol_value_now PARAMS ((symbolS *));
static offsetT get_frag_fix PARAMS ((fragS *));
static void out_set_addr PARAMS ((segT, fragS *, addressT));
static int size_inc_line_addr PARAMS ((int, addressT));
static void emit_inc_line_addr PARAMS ((int, addressT, char *, int));
static void out_inc_line_addr PARAMS ((int, addressT));
static void relax_inc_line_addr PARAMS ((int, segT, fragS *, addressT,
					 fragS *, addressT));
static void process_entries PARAMS ((segT, struct line_entry *));
static void out_file_list PARAMS ((void));
static void out_debug_line PARAMS ((segT));
static void out_debug_aranges PARAMS ((segT, segT));
static void out_debug_abbrev PARAMS ((segT));
static void out_debug_info PARAMS ((segT, segT, segT));

/* Find or create an entry for SEG+SUBSEG in ALL_SEGS.  */

static struct line_subseg *
get_line_subseg (seg, subseg)
     segT seg;
     subsegT subseg;
{
  static segT last_seg;
  static subsegT last_subseg;
  static struct line_subseg *last_line_subseg;

  struct line_seg *s;
  struct line_subseg **pss, *ss;

  if (seg == last_seg && subseg == last_subseg)
    return last_line_subseg;

  for (s = all_segs; s; s = s->next)
    if (s->seg == seg)
      goto found_seg;

  s = (struct line_seg *) xmalloc (sizeof (*s));
  s->next = all_segs;
  s->seg = seg;
  s->head = NULL;
  all_segs = s;

 found_seg:
  for (pss = &s->head; (ss = *pss) != NULL ; pss = &ss->next)
    {
      if (ss->subseg == subseg)
	goto found_subseg;
      if (ss->subseg > subseg)
	break;
    }

  ss = (struct line_subseg *) xmalloc (sizeof (*ss));
  ss->next = *pss;
  ss->subseg = subseg;
  ss->head = NULL;
  ss->ptail = &ss->head;
  *pss = ss;

 found_subseg:
  last_seg = seg;
  last_subseg = subseg;
  last_line_subseg = ss;

  return ss;
}

/* Record an entry for LOC ocurring at OFS within the current fragment.  */

void
dwarf2_gen_line_info (ofs, loc)
     addressT ofs;
     struct dwarf2_line_info *loc;
{
  struct line_subseg *ss;
  struct line_entry *e;

  /* Early out for as-yet incomplete location information.  */
  if (loc->filenum == 0 || loc->line == 0)
    return;

  e = (struct line_entry *) xmalloc (sizeof (*e));
  e->next = NULL;
  e->frag = frag_now;
  e->frag_ofs = ofs;
  e->loc = *loc;

  ss = get_line_subseg (now_seg, now_subseg);
  *ss->ptail = e;
  ss->ptail = &e->next;
}

void
dwarf2_where (line)
     struct dwarf2_line_info *line;
{
  if (debug_type == DEBUG_DWARF2)
    {
      char *filename;
      as_where (&filename, &line->line);
      line->filenum = get_filenum (filename);
      line->column = 0;
      line->flags = DWARF2_FLAG_BEGIN_STMT;
    }
  else
    *line = current;
}

/* Called for each machine instruction, or relatively atomic group of
   machine instructions (ie built-in macro).  The instruction or group
   is SIZE bytes in length.  If dwarf2 line number generation is called
   for, emit a line statement appropriately.  */

void
dwarf2_emit_insn (size)
     int size;
{
  struct dwarf2_line_info loc;

  if (debug_type != DEBUG_DWARF2 && ! loc_directive_seen)
    return;
  loc_directive_seen = false;

  dwarf2_where (&loc);
  dwarf2_gen_line_info (frag_now_fix () - size, &loc);
}

/* Get a .debug_line file number for FILENAME.  */

static unsigned int
get_filenum (filename)
     const char *filename;
{
  static unsigned int last_used;
  unsigned int i;

  if (last_used)
    if (strcmp (filename, files[last_used].filename) == 0)
      return last_used;

  for (i = 1; i < files_in_use; ++i)
    if (strcmp (filename, files[i].filename) == 0)
      return i;

  if (i >= files_allocated)
    {
      unsigned int old = files_allocated;

      files_allocated = i + 32;
      files = (struct file_entry *)
	xrealloc (files, (i + 32) * sizeof (struct file_entry));

      memset (files + old, 0, (i + 32 - old) * sizeof (struct file_entry));
    }

  files[i].filename = xstrdup (filename);
  files[i].dir = 0;
  files_in_use = i + 1;
  last_used = i;

  return i;
}

/* Handle the .file directive.  */

void
dwarf2_directive_file (dummy)
     int dummy ATTRIBUTE_UNUSED;
{
  offsetT num;
  char *filename;
  int filename_len;

  /* Continue to accept a bare string and pass it off.  */
  SKIP_WHITESPACE ();
  if (*input_line_pointer == '"')
    {
      s_app_file (0);
      return;
    }

  num = get_absolute_expression ();
  filename = demand_copy_C_string (&filename_len);
  demand_empty_rest_of_line ();

  if (num < 1)
    {
      as_bad (_("File number less than one"));
      return;
    }

  if (num < files_in_use && files[num].filename != 0)
    {
      as_bad (_("File number %ld already allocated"), (long) num);
      return;
    }

  if (num >= (int) files_allocated)
    {
      unsigned int old = files_allocated;

      files_allocated = num + 16;
      files = (struct file_entry *)
	xrealloc (files, (num + 16) * sizeof (struct file_entry));

      /* Zero the new memory.  */
      memset (files + old, 0, (num + 16 - old) * sizeof (struct file_entry));
    }

  files[num].filename = filename;
  files[num].dir = 0;
  files_in_use = num + 1;
}

void
dwarf2_directive_loc (dummy)
     int dummy ATTRIBUTE_UNUSED;
{
  offsetT filenum, line, column;

  filenum = get_absolute_expression ();
  SKIP_WHITESPACE ();
  line = get_absolute_expression ();
  SKIP_WHITESPACE ();
  column = get_absolute_expression ();
  demand_empty_rest_of_line ();

  if (filenum < 1)
    {
      as_bad (_("File number less than one"));
      return;
    }
  if (filenum >= (int) files_in_use || files[filenum].filename == 0)
    {
      as_bad (_("Unassigned file number %ld"), (long) filenum);
      return;
    }

  current.filenum = filenum;
  current.line = line;
  current.column = column;
  current.flags = DWARF2_FLAG_BEGIN_STMT;

  loc_directive_seen = true;

#ifndef NO_LISTING
  if (listing)
    listing_source_line (line);
#endif
}

static struct frag *
first_frag_for_seg (seg)
     segT seg;
{
  frchainS *f, *first = NULL;

  for (f = frchain_root; f; f = f->frch_next)
    if (f->frch_seg == seg
	&& (! first || first->frch_subseg > f->frch_subseg))
      first = f;

  return first ? first->frch_root : NULL;
}

static struct frag *
last_frag_for_seg (seg)
     segT seg;
{
  frchainS *f, *last = NULL;

  for (f = frchain_root; f; f = f->frch_next)
    if (f->frch_seg == seg
	&& (! last || last->frch_subseg < f->frch_subseg))
      last= f;

  return last ? last->frch_last : NULL;
}

/* Emit a single byte into the current segment.  */

static inline void