path: root/gdb/disasm.c

/* Disassemble support for GDB.

   Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010,
   2011 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 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "target.h"
#include "value.h"
#include "ui-out.h"
#include "gdb_string.h"
#include "disasm.h"
#include "gdbcore.h"
#include "dis-asm.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;
};

/* Like target_read_memory, but slightly different parameters.  */
static int
dis_asm_read_memory (bfd_vma memaddr, gdb_byte *myaddr, unsigned int len,
		     struct disassemble_info *info)
{
  return target_read_memory (memaddr, myaddr, len);
}

/* Like memory_error with slightly different parameters.  */
static void
dis_asm_memory_error (int status, bfd_vma memaddr,
		      struct disassemble_info *info)
{
  memory_error (status, memaddr);
}

/* Like print_address with slightly different parameters.  */
static void
dis_asm_print_address (bfd_vma addr, struct disassemble_info *info)
{
  struct gdbarch *gdbarch = info->application_data;

  print_address (gdbarch, addr, info->stream);
}

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

  /* parts of the symbolic representation of the address */
  int unmapped;
  int offset;
  int line;
  struct cleanup *ui_out_chain;

  for (pc = low; pc < high;)
    {
      char *filename = NULL;
      char *name = NULL;

      QUIT;
      if (how_many >= 0)
	{
	  if (num_displayed >= how_many)
	    break;
	  else
	    num_displayed++;
	}
      ui_out_chain = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
      ui_out_text (uiout, pc_prefix (pc));
      ui_out_field_core_addr (uiout, "address", gdbarch, pc);

      if (!build_address_symbolic (gdbarch, 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, " <");
	  if ((flags & DISASSEMBLY_OMIT_FNAME) == 0)
	    ui_out_field_string (uiout, "func-name", name);
	  ui_out_text (uiout, "+");
	  ui_out_field_int (uiout, "offset", offset);
	  ui_out_text (uiout, ">:\t");
	}
      else
	ui_out_text (uiout, ":\t");

      if (filename != NULL)
	xfree (filename);
      if (name != NULL)
	xfree (name);

      ui_file_rewind (stb->stream);
      if (flags & DISASSEMBLY_RAW_INSN)
        {
          CORE_ADDR old_pc = pc;
          bfd_byte data;
          int status;

          pc += gdbarch_print_insn (gdbarch, pc, di);
          for (;old_pc < pc; old_pc++)
            {
              status = (*di->read_memory_func) (old_pc, &data, 1, di);
              if (status != 0)
                (*di->memory_error_func) (status, old_pc, di);
              ui_out_message (uiout, 0, " %02x", (unsigned)data);
            }
          ui_out_text (uiout, "\t");
        }
      else
        pc += gdbarch_print_insn (gdbarch, pc, di);
      ui_out_field_stream (uiout, "inst", stb);
      ui_file_rewind (stb->stream);
      do_cleanups (ui_out_chain);
      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 gdbarch *gdbarch, 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, int flags, 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;
  int num_displayed = 0;
  struct cleanup *ui_out_chain;
  struct cleanup *ui_out_tuple_chain = make_cleanup (null_cleanup, 0);
  struct cleanup *ui_out_list_chain = make_cleanup (null_cleanup, 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_chain = make_cleanup_ui_out_list_begin_end (uiout, "asm_insns");

  for (i = 0; i < newlines; i++)
    {
      /* 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_chain
		    = make_cleanup_ui_out_tuple_begin_end (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++)
		    {
		      struct cleanup *ui_out_list_chain_line;
		      struct cleanup *ui_out_tuple_chain_line;
		      
		      ui_out_tuple_chain_line
			= make_cleanup_ui_out_tuple_begin_end (uiout,
							       "src_and_asm_line");
		      print_source_lines (symtab, next_line, next_line + 1,
					  0);
		      ui_out_list_chain_line
			= make_cleanup_ui_out_list_begin_end (uiout,
							      "line_asm_insn");
		      do_cleanups (ui_out_list_chain_line);
		      do_cleanups (ui_out_tuple_chain_line);
		    }
		  /* Print the last line and leave list open for
		     asm instructions to be added. */
		  ui_out_tuple_chain
		    = make_cleanup_ui_out_tuple_begin_end (uiout,
							   "src_and_asm_line");
		  print_source_lines (symtab, next_line, mle[i].line + 1, 0);
		}
	    }
	  else
	    {
	      ui_out_tuple_chain
		= make_cleanup_ui_out_tuple_begin_end (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_chain
	    = make_cleanup_ui_out_list_begin_end (uiout, "line_asm_insn");
	}

      num_displayed += dump_insns (gdbarch, uiout, di,
				   mle[i].start_pc, mle[i].end_pc,
				   how_many, flags, stb);

      /* When we've reached the end of the mle array, or we've seen the last
         assembly range for this source line, close out the list/tuple.  */
      if (i == (newlines - 1) || mle[i + 1].line > mle[i].line)
	{
	  do_cleanups (ui_out_list_chain);
	  do_cleanups (ui_out_tuple_chain);
	  ui_out_tuple_chain = make_cleanup (null_cleanup, 0);
	  ui_out_list_chain = make_cleanup (null_cleanup, 0);
	  ui_out_text (uiout, "\n");
	}
      if (how_many >= 0 && num_displayed >= how_many)
	break;
    }
  do_cleanups (ui_out_chain);
}


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

  ui_out_chain = make_cleanup_ui_out_list_begin_end (uiout, "asm_insns");

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

  do_cleanups (ui_out_chain);
}

/* Initialize the disassemble info struct ready for the specified
   stream.  */

static int ATTRIBUTE_PRINTF (2, 3)
fprintf_disasm (void *stream, const char *format, ...)
{
  va_list args;

  va_start (args, format);
  vfprintf_filtered (stream, format, args);
  va_end (args);
  /* Something non -ve.  */
  return 0;
}

static struct disassemble_info
gdb_disassemble_info (struct gdbarch *gdbarch, struct ui_file *file)
{
  struct disassemble_info di;

  init_disassemble_info (&di, file, fprintf_disasm);
  di.flavour = bfd_target_unknown_flavour;
  di.memory_error_func = dis_asm_memory_error;
  di.print_address_func = dis_asm_print_address;
  /* NOTE: cagney/2003-04-28: The original code, from the old Insight
     disassembler had a local optomization here.  By default it would
     access the executable file, instead of the target memory (there
     was a growing list of exceptions though).  Unfortunately, the
     heuristic was flawed.  Commands like "disassemble &variable"
     didn't work as they relied on the access going to the target.
     Further, it has been supperseeded by trust-read-only-sections
     (although that should be superseeded by target_trust..._p()).  */
  di.read_memory_func = dis_asm_read_memory;
  di.arch = gdbarch_bfd_arch_info (gdbarch)->arch;
  di.mach = gdbarch_bfd_arch_info (gdbarch)->mach;
  di.endian = gdbarch_byte_order (gdbarch);
  di.endian_code = gdbarch_byte_order_for_code (gdbarch);
  di.application_data = gdbarch;
  disassemble_init_for_target (&di);
  return di;
}

void
gdb_disassembly (struct gdbarch *gdbarch, struct ui_out *uiout,
		 char *file_string, int flags, int how_many,
		 CORE_ADDR low, CORE_ADDR high)
{
  struct ui_stream *stb = ui_out_stream_new (uiout);
  struct cleanup *cleanups = make_cleanup_ui_out_stream_delete (stb);
  struct disassemble_info di = gdb_disassemble_info (gdbarch, stb->stream);
  /* To collect the instruction outputted from opcodes. */
  struct symtab *symtab = NULL;
  struct linetable_entry *le = NULL;
  int nlines = -1;

  /* 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 (!(flags & DISASSEMBLY_SOURCE) || nlines <= 0
      || symtab == NULL || symtab->linetable == NULL)
    do_assembly_only (gdbarch, uiout, &di, low, high, how_many, flags, stb);

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

  do_cleanups (cleanups);
  gdb_flush (gdb_stdout);
}

/* Print the instruction at address MEMADDR in debugged memory,
   on STREAM.  Returns the length of the instruction, in bytes,
   and, if requested, the number of branch delay slot instructions.  */

int
gdb_print_insn (struct gdbarch *gdbarch, CORE_ADDR memaddr,
		struct ui_file *stream, int *branch_delay_insns)
{
  struct disassemble_info di;
  int length;

  di = gdb_disassemble_info (gdbarch, stream);
  length = gdbarch_print_insn (gdbarch, memaddr, &di);
  if (branch_delay_insns)
    {
      if (di.insn_info_valid)
	*branch_delay_insns = di.branch_delay_insns;
      else
	*branch_delay_insns = 0;
    }
  return length;
}

static void
do_ui_file_delete (void *arg)
{
  ui_file_delete (arg);
}

/* Return the length in bytes of the instruction at address MEMADDR in
   debugged memory.  */

int
gdb_insn_length (struct gdbarch *gdbarch, CORE_ADDR addr)
{
  static struct ui_file *null_stream = NULL;

  /* Dummy file descriptor for the disassembler.  */
  if (!null_stream)
    {
      null_stream = ui_file_new ();
      make_final_cleanup (do_ui_file_delete, null_stream);
    }

  return gdb_print_insn (gdbarch, addr, null_stream, NULL);
}

/* fprintf-function for gdb_buffered_insn_length.  This function is a
   nop, we don't want to print anything, we just want to compute the
   length of the insn.  */

static int ATTRIBUTE_PRINTF (2, 3)
gdb_buffered_insn_length_fprintf (void *stream, const char *format, ...)
{
  return 0;
}

/* Initialize a struct disassemble_info for gdb_buffered_insn_length.  */

static void
gdb_buffered_insn_length_init_dis (struct gdbarch *gdbarch,
				   struct disassemble_info *di,
				   const gdb_byte *insn, int max_len,
				   CORE_ADDR addr)
{
  init_disassemble_info (di, NULL, gdb_buffered_insn_length_fprintf);

  /* init_disassemble_info installs buffer_read_memory, etc.
     so we don't need to do that here.
     The cast is necessary until disassemble_info is const-ified.  */
  di->buffer = (gdb_byte *) insn;
  di->buffer_length = max_len;
  di->buffer_vma = addr;

  di->arch = gdbarch_bfd_arch_info (gdbarch)->arch;
  di->mach = gdbarch_bfd_arch_info (gdbarch)->mach;
  di->endian = gdbarch_byte_order (gdbarch);
  di->endian_code = gdbarch_byte_order_for_code (gdbarch);

  disassemble_init_for_target (di);
}

/* Return the length in bytes of INSN.  MAX_LEN is the size of the
   buffer containing INSN.  */

int
gdb_buffered_insn_length (struct gdbarch *gdbarch,
			  const gdb_byte *insn, int max_len, CORE_ADDR addr)
{
  struct disassemble_info di;

  gdb_buffered_insn_length_init_dis (gdbarch, &di, insn, max_len, addr);

  return gdbarch_print_insn (gdbarch, addr, &di);
}