disasm.c   [plain text]

/* Disassemble support for GDB.

   Copyright 2000, 2001, 2002, 2003 Free Software Foundation, Inc.

   This file is part of GDB.

   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 2 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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "target.h"
#include "value.h"
#include "ui-out.h"
#include "gdb_string.h"

#include "disasm.h"

/* Disassemble functions.
   FIXME: We should get rid of all the duplicate code in gdb that does
   the same thing: disassemble_command() and the gdbtk variation. */

/* This Structure is used to store line number information.
   We need a different sort of line table from the normal one cuz we can't
   depend upon implicit line-end pc's for lines to do the
   reordering in this function.  */

struct dis_line_entry
{
  int line;
  CORE_ADDR start_pc;
  CORE_ADDR end_pc;
};

/* This variable determines where memory used for disassembly is read from. */
int gdb_disassemble_from_exec = -1;

/* This is the memory_read_func for gdb_disassemble when we are
   disassembling from the exec file. */
static int
gdb_dis_asm_read_memory (bfd_vma memaddr, bfd_byte * myaddr,
			 unsigned int len, disassemble_info * info)
{
  extern struct target_ops exec_ops;
  int res;

  errno = 0;
  res = xfer_memory (memaddr, myaddr, len, 0, 0, &exec_ops);

  if (res == len)
    return 0;
  else if (errno == 0)
    return EIO;
  else
    return errno;
}

static int
compare_lines (const void *mle1p, const void *mle2p)
{
  struct dis_line_entry *mle1, *mle2;
  int val;

  mle1 = (struct dis_line_entry *) mle1p;
  mle2 = (struct dis_line_entry *) mle2p;

  val = mle1->line - mle2->line;

  if (val != 0)
    return val;

  return mle1->start_pc - mle2->start_pc;
}

static int
dump_insns (struct ui_out *uiout, disassemble_info * di,
	    CORE_ADDR low, CORE_ADDR high,
	    int how_many, struct ui_stream *stb)
{
  int num_displayed = 0;
  CORE_ADDR pc;

  /* parts of the symbolic representation of the address */
  int unmapped;
  char *filename = NULL;
  char *name = NULL;
  int offset;
  int line;

  for (pc = low; pc < high;)
    {
      QUIT;
      if (how_many >= 0)
	{
	  if (num_displayed >= how_many)
	    break;
	  else
	    num_displayed++;
	}
      ui_out_tuple_begin (uiout, NULL);
      ui_out_field_core_addr (uiout, "address", pc);

      if (!build_address_symbolic (pc, 0, &name, &offset, &filename,
				   &line, &unmapped))
	{
	  /* We don't care now about line, filename and
	     unmapped. But we might in the future. */
	  ui_out_text (uiout, " <");
	  ui_out_field_string (uiout, "func-name", name);
	  ui_out_text (uiout, "+");
	  ui_out_field_int (uiout, "offset", offset);
	  ui_out_text (uiout, ">:\t");
	}
      if (filename != NULL)
	xfree (filename);
      if (name != NULL)
	xfree (name);

      ui_file_rewind (stb->stream);
      pc += TARGET_PRINT_INSN (pc, di);
      ui_out_field_stream (uiout, "inst", stb);
      ui_file_rewind (stb->stream);
      ui_out_tuple_end (uiout);
      ui_out_text (uiout, "\n");
    }
  return num_displayed;
}

/* The idea here is to present a source-O-centric view of a
   function to the user.  This means that things are presented
   in source order, with (possibly) out of order assembly
   immediately following.  */
static void
do_mixed_source_and_assembly (struct ui_out *uiout,
			      struct disassemble_info *di, int nlines,
			      struct linetable_entry *le,
			      CORE_ADDR low, CORE_ADDR high,
			      struct symtab *symtab,
			      int how_many, struct ui_stream *stb)
{
  int newlines = 0;
  struct dis_line_entry *mle;
  struct symtab_and_line sal;
  int i;
  int out_of_order = 0;
  int next_line = 0;
  CORE_ADDR pc;
  int num_displayed = 0;

  mle = (struct dis_line_entry *) alloca (nlines
					  * sizeof (struct dis_line_entry));

  /* Copy linetable entries for this function into our data
     structure, creating end_pc's and setting out_of_order as
     appropriate.  */

  /* First, skip all the preceding functions.  */

  for (i = 0; i < nlines - 1 && le[i].pc < low; i++);

  /* Now, copy all entries before the end of this function.  */

  for (; i < nlines - 1 && le[i].pc < high; i++)
    {
      if (le[i].line == le[i + 1].line && le[i].pc == le[i + 1].pc)
	continue;		/* Ignore duplicates */

      /* Skip any end-of-function markers.  */
      if (le[i].line == 0)
	continue;

      mle[newlines].line = le[i].line;
      if (le[i].line > le[i + 1].line)
	out_of_order = 1;
      mle[newlines].start_pc = le[i].pc;
      mle[newlines].end_pc = le[i + 1].pc;
      newlines++;
    }

  /* If we're on the last line, and it's part of the function,
     then we need to get the end pc in a special way.  */

  if (i == nlines - 1 && le[i].pc < high)
    {
      mle[newlines].line = le[i].line;
      mle[newlines].start_pc = le[i].pc;
      sal = find_pc_line (le[i].pc, 0);
      mle[newlines].end_pc = sal.end;
      newlines++;
    }

  /* Now, sort mle by line #s (and, then by addresses within
     lines). */

  if (out_of_order)
    qsort (mle, newlines, sizeof (struct dis_line_entry), compare_lines);

  /* Now, for each line entry, emit the specified lines (unless
     they have been emitted before), followed by the assembly code
     for that line.  */

  ui_out_list_begin (uiout, "asm_insns");

  for (i = 0; i < newlines; i++)
    {
      int close_list = 1;
      /* Print out everything from next_line to the current line.  */
      if (mle[i].line >= next_line)
	{
	  if (next_line != 0)
	    {
	      /* Just one line to print. */
	      if (next_line == mle[i].line)
		{
		  ui_out_tuple_begin (uiout, "src_and_asm_line");
		  print_source_lines (symtab, next_line, mle[i].line + 1, 0);
		}
	      else
		{
		  /* Several source lines w/o asm instructions associated. */
		  for (; next_line < mle[i].line; next_line++)
		    {
		      ui_out_tuple_begin (uiout, "src_and_asm_line");
		      print_source_lines (symtab, next_line, next_line + 1,
					  0);
		      ui_out_list_begin (uiout, "line_asm_insn");
		      ui_out_list_end (uiout);
		      ui_out_tuple_end (uiout);
		    }
		  /* Print the last line and leave list open for
		     asm instructions to be added. */
		  ui_out_tuple_begin (uiout, "src_and_asm_line");
		  print_source_lines (symtab, next_line, mle[i].line + 1, 0);
		}
	    }
	  else
	    {
	      ui_out_tuple_begin (uiout, "src_and_asm_line");
	      print_source_lines (symtab, mle[i].line, mle[i].line + 1, 0);
	    }

	  next_line = mle[i].line + 1;
	  ui_out_list_begin (uiout, "line_asm_insn");
	  /* Don't close the list if the lines are not in order. */
	  if (i < (newlines - 1) && mle[i + 1].line <= mle[i].line)
	    close_list = 0;
	}

      num_displayed += dump_insns (uiout, di, mle[i].start_pc, mle[i].end_pc,
				   how_many, stb);
      if (close_list)
	{
	  ui_out_list_end (uiout);
	  ui_out_tuple_end (uiout);
	  ui_out_text (uiout, "\n");
	  close_list = 0;
	}
      if (how_many >= 0)
	if (num_displayed >= how_many)
	  break;
    }
  ui_out_list_end (uiout);
}


static void
do_assembly_only (struct ui_out *uiout, disassemble_info * di,
		  CORE_ADDR low, CORE_ADDR high,
		  int how_many, struct ui_stream *stb)
{
  int num_displayed = 0;

  ui_out_list_begin (uiout, "asm_insns");

  num_displayed = dump_insns (uiout, di, low, high, how_many, stb);

  ui_out_list_end (uiout);
}

void
gdb_disassembly (struct ui_out *uiout,
		char *file_string,
		int line_num,
		int mixed_source_and_assembly,
		int how_many, CORE_ADDR low, CORE_ADDR high)
{
  static disassemble_info di;
  static int di_initialized;
  /* To collect the instruction outputted from opcodes. */
  static struct ui_stream *stb = NULL;
  struct symtab *symtab = NULL;
  struct linetable_entry *le = NULL;
  int nlines = -1;

  if (!di_initialized)
    {
      /* We don't add a cleanup for this, because the allocation of
         the stream is done once only for each gdb run, and we need to
         keep it around until the end. Hopefully there won't be any
         errors in the init code below, that make this function bail
         out. */
      stb = ui_out_stream_new (uiout);
      INIT_DISASSEMBLE_INFO_NO_ARCH (di, stb->stream,
				     (fprintf_ftype) fprintf_unfiltered);
      di.flavour = bfd_target_unknown_flavour;
      di.memory_error_func = dis_asm_memory_error;
      di.print_address_func = dis_asm_print_address;
      di_initialized = 1;
    }

  di.mach = TARGET_PRINT_INSN_INFO->mach;
  if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
    di.endian = BFD_ENDIAN_BIG;
  else
    di.endian = BFD_ENDIAN_LITTLE;

  /* If gdb_disassemble_from_exec == -1, then we use the following heuristic to
     determine whether or not to do disassembly from target memory or from the
     exec file:

     If we're debugging a local process, read target memory, instead of the
     exec file.  This makes disassembly of functions in shared libs work
     correctly.  Also, read target memory if we are debugging native threads.

     Else, we're debugging a remote process, and should disassemble from the
     exec file for speed.  However, this is no good if the target modifies its
     code (for relocation, or whatever).  */

  if (gdb_disassemble_from_exec == -1)
    {
      if (strcmp (target_shortname, "child") == 0
	  || strcmp (target_shortname, "procfs") == 0
	  || strcmp (target_shortname, "vxprocess") == 0
	  || strstr (target_shortname, "-threads") != NULL)
	gdb_disassemble_from_exec = 0;	/* It's a child process, read inferior mem */
      else
	gdb_disassemble_from_exec = 1;	/* It's remote, read the exec file */
    }

  if (gdb_disassemble_from_exec)
    di.read_memory_func = gdb_dis_asm_read_memory;
  else
    di.read_memory_func = dis_asm_read_memory;

  /* Assume symtab is valid for whole PC range */
  symtab = find_pc_symtab (low);

  if (symtab != NULL && symtab->linetable != NULL)
    {
      /* Convert the linetable to a bunch of my_line_entry's.  */
      le = symtab->linetable->item;
      nlines = symtab->linetable->nitems;
    }

  if (!mixed_source_and_assembly || nlines <= 0
      || symtab == NULL || symtab->linetable == NULL)
    do_assembly_only (uiout, &di, low, high, how_many, stb);

  else if (mixed_source_and_assembly)
    do_mixed_source_and_assembly (uiout, &di, nlines, le, low,
				  high, symtab, how_many, stb);

  gdb_flush (gdb_stdout);
}