path: root/gcc/dwarf2asm.c

/* Dwarf2 assembler output helper routines.
   Copyright (C) 2001 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC 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.

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


#include "config.h"
#include "system.h"
#include "flags.h"
#include "tree.h"
#include "rtl.h"
#include "output.h"
#include "dwarf2asm.h"
#include "dwarf2.h"
#include "splay-tree.h"
#include "ggc.h"
#include "tm_p.h"


/* How to start an assembler comment.  */
#ifndef ASM_COMMENT_START
#define ASM_COMMENT_START ";#"
#endif

/* Definitions of defaults for assembler-dependent names of various
   pseudo-ops and section names.  These may be overridden in the tm.h
   file (if necessary) for a particular assembler.  */

#ifdef OBJECT_FORMAT_ELF
#ifndef UNALIGNED_SHORT_ASM_OP
#define UNALIGNED_SHORT_ASM_OP		"\t.2byte\t"
#endif
#ifndef UNALIGNED_INT_ASM_OP
#define UNALIGNED_INT_ASM_OP		"\t.4byte\t"
#endif
#ifndef UNALIGNED_DOUBLE_INT_ASM_OP
#define UNALIGNED_DOUBLE_INT_ASM_OP	"\t.8byte\t"
#endif
#endif /* OBJECT_FORMAT_ELF */

#ifndef ASM_BYTE_OP
#define ASM_BYTE_OP			"\t.byte\t"
#endif

/* We don't have unaligned support, let's hope the normal output works for
   .debug_frame.  But we know it won't work for .debug_info.  */
#if !defined(UNALIGNED_INT_ASM_OP) && defined(DWARF2_DEBUGGING_INFO)
 #error DWARF2_DEBUGGING_INFO requires UNALIGNED_INT_ASM_OP.
#endif


#ifdef UNALIGNED_INT_ASM_OP
static const char * unaligned_integer_asm_op  PARAMS ((int));

static inline const char *
unaligned_integer_asm_op (size)
     int size;
{
  const char *op;
  switch (size)
    {
    case 1:
      op = ASM_BYTE_OP;
      break;
    case 2:
      op = UNALIGNED_SHORT_ASM_OP;
      break;
    case 4:
      op = UNALIGNED_INT_ASM_OP;
      break;
    case 8:
#ifdef UNALIGNED_DOUBLE_INT_ASM_OP
      op = UNALIGNED_DOUBLE_INT_ASM_OP;
      break;
#endif
    default:
      abort ();
    }
  return op;
}
#endif /* UNALIGNED_INT_ASM_OP */

/* Output an immediate constant in a given size.  */

void
dw2_asm_output_data VPARAMS ((int size, unsigned HOST_WIDE_INT value,
			      const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  int size;
  unsigned HOST_WIDE_INT value;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  size = va_arg (ap, int);
  value = va_arg (ap, unsigned HOST_WIDE_INT);
  comment = va_arg (ap, const char *);
#endif

  if (size * 8 < HOST_BITS_PER_WIDE_INT)
    value &= ~(~(unsigned HOST_WIDE_INT)0 << (size * 8));

#ifdef UNALIGNED_INT_ASM_OP
  fputs (unaligned_integer_asm_op (size), asm_out_file);
  fprintf (asm_out_file, HOST_WIDE_INT_PRINT_HEX, value);
#else
  assemble_integer (GEN_INT (value), size, 1);
#endif

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
  fputc ('\n', asm_out_file);

  va_end (ap);
}

/* Output the difference between two symbols in a given size.  */
/* ??? There appear to be assemblers that do not like such
   subtraction, but do support ASM_SET_OP.  It's unfortunately
   impossible to do here, since the ASM_SET_OP for the difference
   symbol must appear after both symbols are defined.  */

void
dw2_asm_output_delta VPARAMS ((int size, const char *lab1, const char *lab2,
			       const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  int size;
  const char *lab1, *lab2;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  size = va_arg (ap, int);
  lab1 = va_arg (ap, const char *);
  lab2 = va_arg (ap, const char *);
  comment = va_arg (ap, const char *);
#endif

#ifdef UNALIGNED_INT_ASM_OP
  fputs (unaligned_integer_asm_op (size), asm_out_file);
  assemble_name (asm_out_file, lab1);
  fputc ('-', asm_out_file);
  assemble_name (asm_out_file, lab2);
#else
  assemble_integer (gen_rtx_MINUS (smallest_mode_for_size (size, MODE_INT),
				   gen_rtx_SYMBOL_REF (Pmode, lab1),
				   gen_rtx_SYMBOL_REF (Pmode, lab2)),
		    size, 1);
#endif

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
  fputc ('\n', asm_out_file);

  va_end (ap);
}

/* Output a section-relative reference to a label.  In general this
   can only be done for debugging symbols.  E.g. on most targets with
   the GNU linker, this is accomplished with a direct reference and
   the knowledge that the debugging section will be placed at VMA 0.
   Some targets have special relocations for this that we must use.  */

void
dw2_asm_output_offset VPARAMS ((int size, const char *label,
			       const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  int size;
  const char *label;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  size = va_arg (ap, int);
  label = va_arg (ap, const char *);
  comment = va_arg (ap, const char *);
#endif

#ifdef ASM_OUTPUT_DWARF_OFFSET
  ASM_OUTPUT_DWARF_OFFSET (asm_out_file, size, label);
#else
#ifdef UNALIGNED_INT_ASM_OP
  fputs (unaligned_integer_asm_op (size), asm_out_file);
  assemble_name (asm_out_file, label);
#else
  assemble_integer (gen_rtx_SYMBOL_REF (Pmode, label), size, 1);
#endif
#endif

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
  fputc ('\n', asm_out_file);

  va_end (ap);
}

/* Output a self-relative reference to a label, possibly in a
   different section or object file.  */

void
dw2_asm_output_pcrel VPARAMS ((int size, const char *label,
			       const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  int size;
  const char *label;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  size = va_arg (ap, int);
  label = va_arg (ap, const char *);
  comment = va_arg (ap, const char *);
#endif

#ifdef ASM_OUTPUT_DWARF_PCREL
  ASM_OUTPUT_DWARF_PCREL (asm_out_file, size, label);
#else
#ifdef UNALIGNED_INT_ASM_OP
  fputs (unaligned_integer_asm_op (size), asm_out_file);
  assemble_name (asm_out_file, label);
  fputc ('-', asm_out_file);
  fputc ('.', asm_out_file);
#else
  abort ();
#endif
#endif

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
  fputc ('\n', asm_out_file);

  va_end (ap);
}

/* Output an absolute reference to a label.  */

void
dw2_asm_output_addr VPARAMS ((int size, const char *label,
			      const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  int size;
  const char *label;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  size = va_arg (ap, int);
  label = va_arg (ap, const char *);
  comment = va_arg (ap, const char *);
#endif

#ifdef UNALIGNED_INT_ASM_OP
  fputs (unaligned_integer_asm_op (size), asm_out_file);
  assemble_name (asm_out_file, label);
#else
  assemble_integer (gen_rtx_SYMBOL_REF (Pmode, label), size, 1);
#endif

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
  fputc ('\n', asm_out_file);

  va_end (ap);
}

/* Similar, but use an RTX expression instead of a text label.  */

void
dw2_asm_output_addr_rtx VPARAMS ((int size, rtx addr,
				  const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  int size;
  rtx addr;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  size = va_arg (ap, int);
  addr = va_arg (ap, rtx);
  comment = va_arg (ap, const char *);
#endif

#ifdef UNALIGNED_INT_ASM_OP
  fputs (unaligned_integer_asm_op (size), asm_out_file);
  output_addr_const (asm_out_file, addr);
#else
  assemble_integer (addr, size, 1);
#endif

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
  fputc ('\n', asm_out_file);

  va_end (ap);
}

void
dw2_asm_output_nstring VPARAMS ((const char *str, size_t orig_len,
				 const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  const char *str;
  size_t orig_len;
  const char *comment;
#endif
  va_list ap;
  size_t i, len = orig_len;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  str = va_arg (ap, const char *);
  len = va_arg (ap, size_t);
  comment = va_arg (ap, const char *);
#endif

  if (len == (size_t) -1)
    len = strlen (str);

  if (flag_debug_asm && comment)
    {
      fputs ("\t.ascii \"", asm_out_file);
      for (i = 0; i < len; i++)
	{
	  int c = str[i];
	  if (c == '\"' || c == '\\')
	    fputc ('\\', asm_out_file);
	  if (ISPRINT(c))
	    fputc (c, asm_out_file);
	  else
	    fprintf (asm_out_file, "\\%o", c);
	}
      fprintf (asm_out_file, "\\0\"\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
      fputc ('\n', asm_out_file);
    }
  else
    {
      /* If an explicit length was given, we can't assume there
	 is a null termination in the string buffer.  */
      if (orig_len == (size_t) -1)
	len += 1;
      ASM_OUTPUT_ASCII (asm_out_file, str, len);
      if (orig_len != (size_t) -1)
	fprintf (asm_out_file, "%s0\n", ASM_BYTE_OP);
    }

  va_end (ap);
}


/* Return the size of an unsigned LEB128 quantity.  */

int
size_of_uleb128 (value)
     unsigned HOST_WIDE_INT value;
{
  int size = 0, byte;

  do
    {
      byte = (value & 0x7f);
      value >>= 7;
      size += 1;
    }
  while (value != 0);

  return size;
}

/* Return the size of a signed LEB128 quantity.  */

int
size_of_sleb128 (value)
     HOST_WIDE_INT value;
{
  int size = 0, byte;

  do
    {
      byte = (value & 0x7f);
      value >>= 7;
      size += 1;
    }
  while (!((value == 0 && (byte & 0x40) == 0)
	   || (value == -1 && (byte & 0x40) != 0)));

  return size;
}

/* Output an unsigned LEB128 quantity.  */

void
dw2_asm_output_data_uleb128 VPARAMS ((unsigned HOST_WIDE_INT value,
				      const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  unsigned HOST_WIDE_INT value;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  value = va_arg (ap, unsigned HOST_WIDE_INT);
  comment = va_arg (ap, const char *);
#endif

#ifdef HAVE_AS_LEB128
  fputs ("\t.uleb128 ", asm_out_file);
  fprintf (asm_out_file, HOST_WIDE_INT_PRINT_HEX, value);

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
#else
  {
    unsigned HOST_WIDE_INT work = value;

    fputs (ASM_BYTE_OP, asm_out_file);
    do
      {
	int byte = (work & 0x7f);
	work >>= 7;
	if (work != 0)
	  /* More bytes to follow.  */
	  byte |= 0x80;

	fprintf (asm_out_file, "0x%x", byte);
	if (work != 0)
	  fputc (',', asm_out_file);
      }
    while (work != 0);

  if (flag_debug_asm)
    {
      fprintf (asm_out_file, "\t%s uleb128 ", ASM_COMMENT_START);
      fprintf (asm_out_file, HOST_WIDE_INT_PRINT_HEX, value);
      if (comment)
	{
	  fputs ("; ", asm_out_file);
	  vfprintf (asm_out_file, comment, ap);
	}
    }
  }
#endif
  fputc ('\n', asm_out_file);

  va_end (ap);
}

/* Output an signed LEB128 quantity.  */

void
dw2_asm_output_data_sleb128 VPARAMS ((HOST_WIDE_INT value,
				      const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  HOST_WIDE_INT value;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  value = va_arg (ap, HOST_WIDE_INT);
  comment = va_arg (ap, const char *);
#endif

#ifdef HAVE_AS_LEB128
  fputs ("\t.sleb128 ", asm_out_file);
  fprintf (asm_out_file, HOST_WIDE_INT_PRINT_DEC, value);

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
#else
  {
    HOST_WIDE_INT work = value;
    int more, byte;

    fputs (ASM_BYTE_OP, asm_out_file);
    do
      {
	byte = (work & 0x7f);
	/* arithmetic shift */
	work >>= 7;
	more = !((work == 0 && (byte & 0x40) == 0)
		 || (work == -1 && (byte & 0x40) != 0));
	if (more)
	  byte |= 0x80;

	fprintf (asm_out_file, "0x%x", byte);
	if (more)
	  fputc (',', asm_out_file);
      }
    while (more);

  if (flag_debug_asm)
    {
      fprintf (asm_out_file, "\t%s sleb128 ", ASM_COMMENT_START);
      fprintf (asm_out_file, HOST_WIDE_INT_PRINT_DEC, value);
      if (comment)
	{
	  fputs ("; ", asm_out_file);
	  vfprintf (asm_out_file, comment, ap);
	}
    }
  }
#endif
  fputc ('\n', asm_out_file);

  va_end (ap);
}

void
dw2_asm_output_delta_uleb128 VPARAMS ((const char *lab1 ATTRIBUTE_UNUSED,
				       const char *lab2 ATTRIBUTE_UNUSED,
				       const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  const char *lab1, *lab2;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  lab1 = va_arg (ap, const char *);
  lab2 = va_arg (ap, const char *);
  comment = va_arg (ap, const char *);
#endif

#ifdef HAVE_AS_LEB128
  fputs ("\t.uleb128 ", asm_out_file);
  assemble_name (asm_out_file, lab1);
  fputc ('-', asm_out_file);
  assemble_name (asm_out_file, lab2);
#else
  abort ();
#endif

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
  fputc ('\n', asm_out_file);

  va_end (ap);
}

void
dw2_asm_output_delta_sleb128 VPARAMS ((const char *lab1 ATTRIBUTE_UNUSED,
				       const char *lab2 ATTRIBUTE_UNUSED,
				       const char *comment, ...))
{
#ifndef ANSI_PROTOTYPES
  const char *lab1, *lab2;
  const char *comment;
#endif
  va_list ap;

  VA_START (ap, comment);

#ifndef ANSI_PROTOTYPES
  lab1 = va_arg (ap, const char *);
  lab2 = va_arg (ap, const char *);
  comment = va_arg (ap, const char *);
#endif

#ifdef HAVE_AS_LEB128
  fputs ("\t.sleb128 ", asm_out_file);
  assemble_name (asm_out_file, lab1);
  fputc ('-', asm_out_file);
  assemble_name (asm_out_file, lab2);
#else
  abort ();
#endif

  if (flag_debug_asm && comment)
    {
      fprintf (asm_out_file, "\t%s ", ASM_COMMENT_START);
      vfprintf (asm_out_file, comment, ap);
    }
  fputc ('\n', asm_out_file);

  va_end (ap);
}

static rtx dw2_force_const_mem PARAMS ((rtx));
static int dw2_output_indirect_constant_1 PARAMS ((splay_tree_node, void *));

static splay_tree indirect_pool;

static rtx
dw2_force_const_mem (x)
     rtx x;
{
  splay_tree_node node;
  const char *const_sym;

  if (! indirect_pool)
    indirect_pool = splay_tree_new (splay_tree_compare_pointers, NULL, NULL);

  if (GET_CODE (x) != SYMBOL_REF)
    abort ();
  node = splay_tree_lookup (indirect_pool, (splay_tree_key) XSTR (x, 0));
  if (node)
    const_sym = (const char *) node->value;
  else
    {
      extern int const_labelno;
      char label[32];
      tree id;

      ASM_GENERATE_INTERNAL_LABEL (label, "LC", const_labelno);
      ++const_labelno;
      const_sym = ggc_strdup (label);

      id = maybe_get_identifier (XSTR (x, 0));
      if (id)
	TREE_SYMBOL_REFERENCED (id) = 1;

      splay_tree_insert (indirect_pool, (splay_tree_key) XSTR (x, 0),
			 (splay_tree_value) const_sym);
    }

  return gen_rtx_SYMBOL_REF (Pmode, const_sym);
}

static int
dw2_output_indirect_constant_1 (node, data)
     splay_tree_node node;
     void* data ATTRIBUTE_UNUSED;
{
  const char *label, *sym;
  rtx sym_ref;

  label = (const char *) node->value;
  sym = (const char *) node->key;
  sym_ref = gen_rtx_SYMBOL_REF (Pmode, sym);

  ASM_OUTPUT_LABEL (asm_out_file, label);
  assemble_integer (sym_ref, POINTER_SIZE / BITS_PER_UNIT, 1);

  return 0;
}

void
dw2_output_indirect_constants ()
{
  if (! indirect_pool)
    return;

  /* Assume that the whole reason we're emitting these symbol references
     indirectly is that they contain dynamic relocations, and are thus
     read-write.  If there was no possibility of a dynamic relocation, we
     might as well have used a direct relocation.  */
  data_section ();

  /* Everything we're emitting is a pointer.  Align appropriately.  */
  assemble_align (POINTER_SIZE);

  splay_tree_foreach (indirect_pool, dw2_output_indirect_constant_1, NULL);
}

void
dw2_asm_output_encoded_addr_rtx (encoding, addr)
     int encoding;
     rtx addr;
{
  int size;

  switch (encoding & 0x07)
    {
    case DW_EH_PE_absptr:
      size = POINTER_SIZE / BITS_PER_UNIT;
      break;
    case DW_EH_PE_udata2:
      size = 2;
      break;
    case DW_EH_PE_udata4:
      size = 4;
      break;
    case DW_EH_PE_udata8:
      size = 8;
      break;
    default:
      abort ();
    }

  /* NULL is _always_ represented as a plain zero.  */
  if (addr == const0_rtx)
    {
      assemble_integer (addr, size, 1);
      return;
    }

 restart:

  /* Allow the target first crack at emitting this.  Some of the
     special relocations require special directives instead of 
     just ".4byte" or whatever.  */
#ifdef ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX
  ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(asm_out_file, encoding, size, addr, done);
#endif

  /* Indirection is used to get dynamic relocations out of a read-only
     section.  */
  if (encoding & DW_EH_PE_indirect)
    {
      /* It is very tempting to use force_const_mem so that we share data
	 with the normal constant pool.  However, we've already emitted
	 the constant pool for this function.  Moreover, we'd like to share
	 these constants across the entire unit of translation, or better,
	 across the entire application (or DSO).  */
      addr = dw2_force_const_mem (addr);
      encoding &= ~DW_EH_PE_indirect;
      goto restart;
    }

  switch (encoding & 0xF0)
    {
    case DW_EH_PE_absptr:
#ifdef UNALIGNED_INT_ASM_OP
      fputs (unaligned_integer_asm_op (size), asm_out_file);
      output_addr_const (asm_out_file, addr);
#else
      assemble_integer (addr, size, 1);
#endif
      break;

    case DW_EH_PE_pcrel:
      if (GET_CODE (addr) != SYMBOL_REF)
	abort ();
#ifdef ASM_OUTPUT_DWARF_PCREL
      ASM_OUTPUT_DWARF_PCREL (asm_out_file, size, XSTR (addr, 0));
#else
#ifdef UNALIGNED_INT_ASM_OP
      fputs (unaligned_integer_asm_op (size), asm_out_file);
      assemble_name (asm_out_file, XSTR (addr, 0));
      fputc ('-', asm_out_file);
      fputc ('.', asm_out_file);
#else
      abort ();
#endif
#endif
      break;

    default:
      /* Other encodings should have been handled by 
	 ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX.  */
      abort ();
    }

#ifdef ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX
 done:
#endif
  fputc ('\n', asm_out_file);
}