Emit DW_AT_ranges for inlined subroutines that contain disjoint blocks.

[pf3gnuchains/gcc-fork.git] / gcc / dwarf2out.c

/* Output Dwarf2 format symbol table information from GCC.
   Copyright (C) 1992, 1993, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
   2003, 2004, 2005 Free Software Foundation, Inc.
   Contributed by Gary Funck (gary@intrepid.com).
   Derived from DWARF 1 implementation of Ron Guilmette (rfg@monkeys.com).
   Extensively modified by Jason Merrill (jason@cygnus.com).

This file is part of GCC.

GCC 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.

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

/* TODO: Emit .debug_line header even when there are no functions, since
           the file numbers are used by .debug_info.  Alternately, leave
           out locations for types and decls.
         Avoid talking about ctors and op= for PODs.
         Factor out common prologue sequences into multiple CIEs.  */

/* The first part of this file deals with the DWARF 2 frame unwind
   information, which is also used by the GCC efficient exception handling
   mechanism.  The second part, controlled only by an #ifdef
   DWARF2_DEBUGGING_INFO, deals with the other DWARF 2 debugging
   information.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "version.h"
#include "flags.h"
#include "real.h"
#include "rtl.h"
#include "hard-reg-set.h"
#include "regs.h"
#include "insn-config.h"
#include "reload.h"
#include "function.h"
#include "output.h"
#include "expr.h"
#include "libfuncs.h"
#include "except.h"
#include "dwarf2.h"
#include "dwarf2out.h"
#include "dwarf2asm.h"
#include "toplev.h"
#include "varray.h"
#include "ggc.h"
#include "md5.h"
#include "tm_p.h"
#include "diagnostic.h"
#include "debug.h"
#include "target.h"
#include "langhooks.h"
#include "hashtab.h"
#include "cgraph.h"
#include "input.h"

#ifdef DWARF2_DEBUGGING_INFO
static void dwarf2out_source_line (unsigned int, const char *);
#endif

/* DWARF2 Abbreviation Glossary:
   CFA = Canonical Frame Address
           a fixed address on the stack which identifies a call frame.
           We define it to be the value of SP just before the call insn.
           The CFA register and offset, which may change during the course
           of the function, are used to calculate its value at runtime.
   CFI = Call Frame Instruction
           an instruction for the DWARF2 abstract machine
   CIE = Common Information Entry
           information describing information common to one or more FDEs
   DIE = Debugging Information Entry
   FDE = Frame Description Entry
           information describing the stack call frame, in particular,
           how to restore registers

   DW_CFA_... = DWARF2 CFA call frame instruction
   DW_TAG_... = DWARF2 DIE tag */

/* Decide whether we want to emit frame unwind information for the current
   translation unit.  */

int
dwarf2out_do_frame (void)
{
  return (write_symbols == DWARF2_DEBUG
          || write_symbols == VMS_AND_DWARF2_DEBUG
#ifdef DWARF2_FRAME_INFO
          || DWARF2_FRAME_INFO
#endif
#ifdef DWARF2_UNWIND_INFO
          || flag_unwind_tables
          || (flag_exceptions && ! USING_SJLJ_EXCEPTIONS)
#endif
          );
}

/* The size of the target's pointer type.  */
#ifndef PTR_SIZE
#define PTR_SIZE (POINTER_SIZE / BITS_PER_UNIT)
#endif

/* Various versions of targetm.eh_frame_section.  Note these must appear
   outside the DWARF2_DEBUGGING_INFO || DWARF2_UNWIND_INFO macro guards.  */

/* Version of targetm.eh_frame_section for systems with named sections.  */
void
named_section_eh_frame_section (void)
{
#ifdef EH_FRAME_SECTION_NAME
  int flags;

  if (EH_TABLES_CAN_BE_READ_ONLY)
    {
      int fde_encoding;
      int per_encoding;
      int lsda_encoding;

      fde_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/1, /*global=*/0);
      per_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/2, /*global=*/1);
      lsda_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0, /*global=*/0);
      flags = (! flag_pic
               || ((fde_encoding & 0x70) != DW_EH_PE_absptr
                   && (fde_encoding & 0x70) != DW_EH_PE_aligned
                   && (per_encoding & 0x70) != DW_EH_PE_absptr
                   && (per_encoding & 0x70) != DW_EH_PE_aligned
                   && (lsda_encoding & 0x70) != DW_EH_PE_absptr
                   && (lsda_encoding & 0x70) != DW_EH_PE_aligned))
              ? 0 : SECTION_WRITE;
    }
  else
    flags = SECTION_WRITE;
  named_section_flags (EH_FRAME_SECTION_NAME, flags);
#endif
}

/* Version of targetm.eh_frame_section for systems using collect2.  */
void
collect2_eh_frame_section (void)
{
  tree label = get_file_function_name ('F');

  data_section ();
  ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (PTR_SIZE));
  targetm.asm_out.globalize_label (asm_out_file, IDENTIFIER_POINTER (label));
  ASM_OUTPUT_LABEL (asm_out_file, IDENTIFIER_POINTER (label));
}

/* Default version of targetm.eh_frame_section.  */
void
default_eh_frame_section (void)
{
#ifdef EH_FRAME_SECTION_NAME
  named_section_eh_frame_section ();
#else
  collect2_eh_frame_section ();
#endif
}

/* Array of RTXes referenced by the debugging information, which therefore
   must be kept around forever.  */
static GTY(()) varray_type used_rtx_varray;

/* A pointer to the base of a list of incomplete types which might be
   completed at some later time.  incomplete_types_list needs to be a VARRAY
   because we want to tell the garbage collector about it.  */
static GTY(()) varray_type incomplete_types;

/* A pointer to the base of a table of references to declaration
   scopes.  This table is a display which tracks the nesting
   of declaration scopes at the current scope and containing
   scopes.  This table is used to find the proper place to
   define type declaration DIE's.  */
static GTY(()) varray_type decl_scope_table;

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

typedef struct dw_cfi_struct *dw_cfi_ref;
typedef struct dw_fde_struct *dw_fde_ref;
typedef union  dw_cfi_oprnd_struct *dw_cfi_oprnd_ref;

/* Call frames are described using a sequence of Call Frame
   Information instructions.  The register number, offset
   and address fields are provided as possible operands;
   their use is selected by the opcode field.  */

enum dw_cfi_oprnd_type {
  dw_cfi_oprnd_unused,
  dw_cfi_oprnd_reg_num,
  dw_cfi_oprnd_offset,
  dw_cfi_oprnd_addr,
  dw_cfi_oprnd_loc
};

typedef union dw_cfi_oprnd_struct GTY(())
{
  unsigned long GTY ((tag ("dw_cfi_oprnd_reg_num"))) dw_cfi_reg_num;
  HOST_WIDE_INT GTY ((tag ("dw_cfi_oprnd_offset"))) dw_cfi_offset;
  const char * GTY ((tag ("dw_cfi_oprnd_addr"))) dw_cfi_addr;
  struct dw_loc_descr_struct * GTY ((tag ("dw_cfi_oprnd_loc"))) dw_cfi_loc;
}
dw_cfi_oprnd;

typedef struct dw_cfi_struct GTY(())
{
  dw_cfi_ref dw_cfi_next;
  enum dwarf_call_frame_info dw_cfi_opc;
  dw_cfi_oprnd GTY ((desc ("dw_cfi_oprnd1_desc (%1.dw_cfi_opc)")))
    dw_cfi_oprnd1;
  dw_cfi_oprnd GTY ((desc ("dw_cfi_oprnd2_desc (%1.dw_cfi_opc)")))
    dw_cfi_oprnd2;
}
dw_cfi_node;

/* This is how we define the location of the CFA. We use to handle it
   as REG + OFFSET all the time,  but now it can be more complex.
   It can now be either REG + CFA_OFFSET or *(REG + BASE_OFFSET) + CFA_OFFSET.
   Instead of passing around REG and OFFSET, we pass a copy
   of this structure.  */
typedef struct cfa_loc GTY(())
{
  unsigned long reg;
  HOST_WIDE_INT offset;
  HOST_WIDE_INT base_offset;
  int indirect;            /* 1 if CFA is accessed via a dereference.  */
} dw_cfa_location;

/* All call frame descriptions (FDE's) in the GCC generated DWARF
   refer to a single Common Information Entry (CIE), defined at
   the beginning of the .debug_frame section.  This use of a single
   CIE obviates the need to keep track of multiple CIE's
   in the DWARF generation routines below.  */

typedef struct dw_fde_struct GTY(())
{
  tree decl;
  const char *dw_fde_begin;
  const char *dw_fde_current_label;
  const char *dw_fde_end;
  dw_cfi_ref dw_fde_cfi;
  unsigned funcdef_number;
  unsigned all_throwers_are_sibcalls : 1;
  unsigned nothrow : 1;
  unsigned uses_eh_lsda : 1;
}
dw_fde_node;

/* Maximum size (in bytes) of an artificially generated label.  */
#define MAX_ARTIFICIAL_LABEL_BYTES      30

/* The size of addresses as they appear in the Dwarf 2 data.
   Some architectures use word addresses to refer to code locations,
   but Dwarf 2 info always uses byte addresses.  On such machines,
   Dwarf 2 addresses need to be larger than the architecture's
   pointers.  */
#ifndef DWARF2_ADDR_SIZE
#define DWARF2_ADDR_SIZE (POINTER_SIZE / BITS_PER_UNIT)
#endif

/* The size in bytes of a DWARF field indicating an offset or length
   relative to a debug info section, specified to be 4 bytes in the
   DWARF-2 specification.  The SGI/MIPS ABI defines it to be the same
   as PTR_SIZE.  */

#ifndef DWARF_OFFSET_SIZE
#define DWARF_OFFSET_SIZE 4
#endif

/* According to the (draft) DWARF 3 specification, the initial length
   should either be 4 or 12 bytes.  When it's 12 bytes, the first 4
   bytes are 0xffffffff, followed by the length stored in the next 8
   bytes.

   However, the SGI/MIPS ABI uses an initial length which is equal to
   DWARF_OFFSET_SIZE.  It is defined (elsewhere) accordingly.  */

#ifndef DWARF_INITIAL_LENGTH_SIZE
#define DWARF_INITIAL_LENGTH_SIZE (DWARF_OFFSET_SIZE == 4 ? 4 : 12)
#endif

#define DWARF_VERSION 2

/* Round SIZE up to the nearest BOUNDARY.  */
#define DWARF_ROUND(SIZE,BOUNDARY) \
  ((((SIZE) + (BOUNDARY) - 1) / (BOUNDARY)) * (BOUNDARY))

/* Offsets recorded in opcodes are a multiple of this alignment factor.  */
#ifndef DWARF_CIE_DATA_ALIGNMENT
#ifdef STACK_GROWS_DOWNWARD
#define DWARF_CIE_DATA_ALIGNMENT (-((int) UNITS_PER_WORD))
#else
#define DWARF_CIE_DATA_ALIGNMENT ((int) UNITS_PER_WORD)
#endif
#endif

/* A pointer to the base of a table that contains frame description
   information for each routine.  */
static GTY((length ("fde_table_allocated"))) dw_fde_ref fde_table;

/* Number of elements currently allocated for fde_table.  */
static GTY(()) unsigned fde_table_allocated;

/* Number of elements in fde_table currently in use.  */
static GTY(()) unsigned fde_table_in_use;

/* Size (in elements) of increments by which we may expand the
   fde_table.  */
#define FDE_TABLE_INCREMENT 256

/* A list of call frame insns for the CIE.  */
static GTY(()) dw_cfi_ref cie_cfi_head;

#if defined (DWARF2_DEBUGGING_INFO) || defined (DWARF2_UNWIND_INFO)
/* Some DWARF extensions (e.g., MIPS/SGI) implement a subprogram
   attribute that accelerates the lookup of the FDE associated
   with the subprogram.  This variable holds the table index of the FDE
   associated with the current function (body) definition.  */
static unsigned current_funcdef_fde;
#endif

struct indirect_string_node GTY(())
{
  const char *str;
  unsigned int refcount;
  unsigned int form;
  char *label;
};

static GTY ((param_is (struct indirect_string_node))) htab_t debug_str_hash;

static GTY(()) int dw2_string_counter;
static GTY(()) unsigned long dwarf2out_cfi_label_num;

#if defined (DWARF2_DEBUGGING_INFO) || defined (DWARF2_UNWIND_INFO)

/* Forward declarations for functions defined in this file.  */

static char *stripattributes (const char *);
static const char *dwarf_cfi_name (unsigned);
static dw_cfi_ref new_cfi (void);
static void add_cfi (dw_cfi_ref *, dw_cfi_ref);
static void add_fde_cfi (const char *, dw_cfi_ref);
static void lookup_cfa_1 (dw_cfi_ref, dw_cfa_location *);
static void lookup_cfa (dw_cfa_location *);
static void reg_save (const char *, unsigned, unsigned, HOST_WIDE_INT);
static void initial_return_save (rtx);
static HOST_WIDE_INT stack_adjust_offset (rtx);
static void output_cfi (dw_cfi_ref, dw_fde_ref, int);
static void output_call_frame_info (int);
static void dwarf2out_stack_adjust (rtx, bool);
static void flush_queued_reg_saves (void);
static bool clobbers_queued_reg_save (rtx);
static void dwarf2out_frame_debug_expr (rtx, const char *);

/* Support for complex CFA locations.  */
static void output_cfa_loc (dw_cfi_ref);
static void get_cfa_from_loc_descr (dw_cfa_location *,
                                    struct dw_loc_descr_struct *);
static struct dw_loc_descr_struct *build_cfa_loc
 (dw_cfa_location *);
static void def_cfa_1 (const char *, dw_cfa_location *);

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

/* Data and reference forms for relocatable data.  */
#define DW_FORM_data (DWARF_OFFSET_SIZE == 8 ? DW_FORM_data8 : DW_FORM_data4)
#define DW_FORM_ref (DWARF_OFFSET_SIZE == 8 ? DW_FORM_ref8 : DW_FORM_ref4)

#ifndef DEBUG_FRAME_SECTION
#define DEBUG_FRAME_SECTION     ".debug_frame"
#endif

#ifndef FUNC_BEGIN_LABEL
#define FUNC_BEGIN_LABEL        "LFB"
#endif

#ifndef FUNC_END_LABEL
#define FUNC_END_LABEL          "LFE"
#endif

#ifndef FRAME_BEGIN_LABEL
#define FRAME_BEGIN_LABEL       "Lframe"
#endif
#define CIE_AFTER_SIZE_LABEL    "LSCIE"
#define CIE_END_LABEL           "LECIE"
#define FDE_LABEL               "LSFDE"
#define FDE_AFTER_SIZE_LABEL    "LASFDE"
#define FDE_END_LABEL           "LEFDE"
#define LINE_NUMBER_BEGIN_LABEL "LSLT"
#define LINE_NUMBER_END_LABEL   "LELT"
#define LN_PROLOG_AS_LABEL      "LASLTP"
#define LN_PROLOG_END_LABEL     "LELTP"
#define DIE_LABEL_PREFIX        "DW"

/* The DWARF 2 CFA column which tracks the return address.  Normally this
   is the column for PC, or the first column after all of the hard
   registers.  */
#ifndef DWARF_FRAME_RETURN_COLUMN
#ifdef PC_REGNUM
#define DWARF_FRAME_RETURN_COLUMN       DWARF_FRAME_REGNUM (PC_REGNUM)
#else
#define DWARF_FRAME_RETURN_COLUMN       DWARF_FRAME_REGISTERS
#endif
#endif

/* The mapping from gcc register number to DWARF 2 CFA column number.  By
   default, we just provide columns for all registers.  */
#ifndef DWARF_FRAME_REGNUM
#define DWARF_FRAME_REGNUM(REG) DBX_REGISTER_NUMBER (REG)
#endif

/* The offset from the incoming value of %sp to the top of the stack frame
   for the current function.  */
#ifndef INCOMING_FRAME_SP_OFFSET
#define INCOMING_FRAME_SP_OFFSET 0
#endif
\f
/* Hook used by __throw.  */

rtx
expand_builtin_dwarf_sp_column (void)
{
  return GEN_INT (DWARF_FRAME_REGNUM (STACK_POINTER_REGNUM));
}

/* Return a pointer to a copy of the section string name S with all
   attributes stripped off, and an asterisk prepended (for assemble_name).  */

static inline char *
stripattributes (const char *s)
{
  char *stripped = xmalloc (strlen (s) + 2);
  char *p = stripped;

  *p++ = '*';

  while (*s && *s != ',')
    *p++ = *s++;

  *p = '\0';
  return stripped;
}

/* Generate code to initialize the register size table.  */

void
expand_builtin_init_dwarf_reg_sizes (tree address)
{
  int i;
  enum machine_mode mode = TYPE_MODE (char_type_node);
  rtx addr = expand_expr (address, NULL_RTX, VOIDmode, 0);
  rtx mem = gen_rtx_MEM (BLKmode, addr);
  bool wrote_return_column = false;

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    if (DWARF_FRAME_REGNUM (i) < DWARF_FRAME_REGISTERS)
      {
        HOST_WIDE_INT offset = DWARF_FRAME_REGNUM (i) * GET_MODE_SIZE (mode);
        enum machine_mode save_mode = reg_raw_mode[i];
        HOST_WIDE_INT size;

        if (HARD_REGNO_CALL_PART_CLOBBERED (i, save_mode))
          save_mode = choose_hard_reg_mode (i, 1, true);
        if (DWARF_FRAME_REGNUM (i) == DWARF_FRAME_RETURN_COLUMN)
          {
            if (save_mode == VOIDmode)
              continue;
            wrote_return_column = true;
          }
        size = GET_MODE_SIZE (save_mode);
        if (offset < 0)
          continue;

        emit_move_insn (adjust_address (mem, mode, offset), GEN_INT (size));
      }

#ifdef DWARF_ALT_FRAME_RETURN_COLUMN
  gcc_assert (wrote_return_column);
  i = DWARF_ALT_FRAME_RETURN_COLUMN;
  wrote_return_column = false;
#else
  i = DWARF_FRAME_RETURN_COLUMN;
#endif

  if (! wrote_return_column)
    {
      enum machine_mode save_mode = Pmode;
      HOST_WIDE_INT offset = i * GET_MODE_SIZE (mode);
      HOST_WIDE_INT size = GET_MODE_SIZE (save_mode);
      emit_move_insn (adjust_address (mem, mode, offset), GEN_INT (size));
    }
}

/* Convert a DWARF call frame info. operation to its string name */

static const char *
dwarf_cfi_name (unsigned int cfi_opc)
{
  switch (cfi_opc)
    {
    case DW_CFA_advance_loc:
      return "DW_CFA_advance_loc";
    case DW_CFA_offset:
      return "DW_CFA_offset";
    case DW_CFA_restore:
      return "DW_CFA_restore";
    case DW_CFA_nop:
      return "DW_CFA_nop";
    case DW_CFA_set_loc:
      return "DW_CFA_set_loc";
    case DW_CFA_advance_loc1:
      return "DW_CFA_advance_loc1";
    case DW_CFA_advance_loc2:
      return "DW_CFA_advance_loc2";
    case DW_CFA_advance_loc4:
      return "DW_CFA_advance_loc4";
    case DW_CFA_offset_extended:
      return "DW_CFA_offset_extended";
    case DW_CFA_restore_extended:
      return "DW_CFA_restore_extended";
    case DW_CFA_undefined:
      return "DW_CFA_undefined";
    case DW_CFA_same_value:
      return "DW_CFA_same_value";
    case DW_CFA_register:
      return "DW_CFA_register";
    case DW_CFA_remember_state:
      return "DW_CFA_remember_state";
    case DW_CFA_restore_state:
      return "DW_CFA_restore_state";
    case DW_CFA_def_cfa:
      return "DW_CFA_def_cfa";
    case DW_CFA_def_cfa_register:
      return "DW_CFA_def_cfa_register";
    case DW_CFA_def_cfa_offset:
      return "DW_CFA_def_cfa_offset";

    /* DWARF 3 */
    case DW_CFA_def_cfa_expression:
      return "DW_CFA_def_cfa_expression";
    case DW_CFA_expression:
      return "DW_CFA_expression";
    case DW_CFA_offset_extended_sf:
      return "DW_CFA_offset_extended_sf";
    case DW_CFA_def_cfa_sf:
      return "DW_CFA_def_cfa_sf";
    case DW_CFA_def_cfa_offset_sf:
      return "DW_CFA_def_cfa_offset_sf";

    /* SGI/MIPS specific */
    case DW_CFA_MIPS_advance_loc8:
      return "DW_CFA_MIPS_advance_loc8";

    /* GNU extensions */
    case DW_CFA_GNU_window_save:
      return "DW_CFA_GNU_window_save";
    case DW_CFA_GNU_args_size:
      return "DW_CFA_GNU_args_size";
    case DW_CFA_GNU_negative_offset_extended:
      return "DW_CFA_GNU_negative_offset_extended";

    default:
      return "DW_CFA_<unknown>";
    }
}

/* Return a pointer to a newly allocated Call Frame Instruction.  */

static inline dw_cfi_ref
new_cfi (void)
{
  dw_cfi_ref cfi = ggc_alloc (sizeof (dw_cfi_node));

  cfi->dw_cfi_next = NULL;
  cfi->dw_cfi_oprnd1.dw_cfi_reg_num = 0;
  cfi->dw_cfi_oprnd2.dw_cfi_reg_num = 0;

  return cfi;
}

/* Add a Call Frame Instruction to list of instructions.  */

static inline void
add_cfi (dw_cfi_ref *list_head, dw_cfi_ref cfi)
{
  dw_cfi_ref *p;

  /* Find the end of the chain.  */
  for (p = list_head; (*p) != NULL; p = &(*p)->dw_cfi_next)
    ;

  *p = cfi;
}

/* Generate a new label for the CFI info to refer to.  */

char *
dwarf2out_cfi_label (void)
{
  static char label[20];

  ASM_GENERATE_INTERNAL_LABEL (label, "LCFI", dwarf2out_cfi_label_num++);
  ASM_OUTPUT_LABEL (asm_out_file, label);
  return label;
}

/* Add CFI to the current fde at the PC value indicated by LABEL if specified,
   or to the CIE if LABEL is NULL.  */

static void
add_fde_cfi (const char *label, dw_cfi_ref cfi)
{
  if (label)
    {
      dw_fde_ref fde = &fde_table[fde_table_in_use - 1];

      if (*label == 0)
        label = dwarf2out_cfi_label ();

      if (fde->dw_fde_current_label == NULL
          || strcmp (label, fde->dw_fde_current_label) != 0)
        {
          dw_cfi_ref xcfi;

          fde->dw_fde_current_label = label = xstrdup (label);

          /* Set the location counter to the new label.  */
          xcfi = new_cfi ();
          xcfi->dw_cfi_opc = DW_CFA_advance_loc4;
          xcfi->dw_cfi_oprnd1.dw_cfi_addr = label;
          add_cfi (&fde->dw_fde_cfi, xcfi);
        }

      add_cfi (&fde->dw_fde_cfi, cfi);
    }

  else
    add_cfi (&cie_cfi_head, cfi);
}

/* Subroutine of lookup_cfa.  */

static inline void
lookup_cfa_1 (dw_cfi_ref cfi, dw_cfa_location *loc)
{
  switch (cfi->dw_cfi_opc)
    {
    case DW_CFA_def_cfa_offset:
      loc->offset = cfi->dw_cfi_oprnd1.dw_cfi_offset;
      break;
    case DW_CFA_def_cfa_register:
      loc->reg = cfi->dw_cfi_oprnd1.dw_cfi_reg_num;
      break;
    case DW_CFA_def_cfa:
      loc->reg = cfi->dw_cfi_oprnd1.dw_cfi_reg_num;
      loc->offset = cfi->dw_cfi_oprnd2.dw_cfi_offset;
      break;
    case DW_CFA_def_cfa_expression:
      get_cfa_from_loc_descr (loc, cfi->dw_cfi_oprnd1.dw_cfi_loc);
      break;
    default:
      break;
    }
}

/* Find the previous value for the CFA.  */

static void
lookup_cfa (dw_cfa_location *loc)
{
  dw_cfi_ref cfi;

  loc->reg = (unsigned long) -1;
  loc->offset = 0;
  loc->indirect = 0;
  loc->base_offset = 0;

  for (cfi = cie_cfi_head; cfi; cfi = cfi->dw_cfi_next)
    lookup_cfa_1 (cfi, loc);

  if (fde_table_in_use)
    {
      dw_fde_ref fde = &fde_table[fde_table_in_use - 1];
      for (cfi = fde->dw_fde_cfi; cfi; cfi = cfi->dw_cfi_next)
        lookup_cfa_1 (cfi, loc);
    }
}

/* The current rule for calculating the DWARF2 canonical frame address.  */
static dw_cfa_location cfa;

/* The register used for saving registers to the stack, and its offset
   from the CFA.  */
static dw_cfa_location cfa_store;

/* The running total of the size of arguments pushed onto the stack.  */
static HOST_WIDE_INT args_size;

/* The last args_size we actually output.  */
static HOST_WIDE_INT old_args_size;

/* Entry point to update the canonical frame address (CFA).
   LABEL is passed to add_fde_cfi.  The value of CFA is now to be
   calculated from REG+OFFSET.  */

void
dwarf2out_def_cfa (const char *label, unsigned int reg, HOST_WIDE_INT offset)
{
  dw_cfa_location loc;
  loc.indirect = 0;
  loc.base_offset = 0;
  loc.reg = reg;
  loc.offset = offset;
  def_cfa_1 (label, &loc);
}

/* This routine does the actual work.  The CFA is now calculated from
   the dw_cfa_location structure.  */

static void
def_cfa_1 (const char *label, dw_cfa_location *loc_p)
{
  dw_cfi_ref cfi;
  dw_cfa_location old_cfa, loc;

  cfa = *loc_p;
  loc = *loc_p;

  if (cfa_store.reg == loc.reg && loc.indirect == 0)
    cfa_store.offset = loc.offset;

  loc.reg = DWARF_FRAME_REGNUM (loc.reg);
  lookup_cfa (&old_cfa);

  /* If nothing changed, no need to issue any call frame instructions.  */
  if (loc.reg == old_cfa.reg && loc.offset == old_cfa.offset
      && loc.indirect == old_cfa.indirect
      && (loc.indirect == 0 || loc.base_offset == old_cfa.base_offset))
    return;

  cfi = new_cfi ();

  if (loc.reg == old_cfa.reg && !loc.indirect)
    {
      /* Construct a "DW_CFA_def_cfa_offset <offset>" instruction,
         indicating the CFA register did not change but the offset
         did.  */
      cfi->dw_cfi_opc = DW_CFA_def_cfa_offset;
      cfi->dw_cfi_oprnd1.dw_cfi_offset = loc.offset;
    }

#ifndef MIPS_DEBUGGING_INFO  /* SGI dbx thinks this means no offset.  */
  else if (loc.offset == old_cfa.offset && old_cfa.reg != (unsigned long) -1
           && !loc.indirect)
    {
      /* Construct a "DW_CFA_def_cfa_register <register>" instruction,
         indicating the CFA register has changed to <register> but the
         offset has not changed.  */
      cfi->dw_cfi_opc = DW_CFA_def_cfa_register;
      cfi->dw_cfi_oprnd1.dw_cfi_reg_num = loc.reg;
    }
#endif

  else if (loc.indirect == 0)
    {
      /* Construct a "DW_CFA_def_cfa <register> <offset>" instruction,
         indicating the CFA register has changed to <register> with
         the specified offset.  */
      cfi->dw_cfi_opc = DW_CFA_def_cfa;
      cfi->dw_cfi_oprnd1.dw_cfi_reg_num = loc.reg;
      cfi->dw_cfi_oprnd2.dw_cfi_offset = loc.offset;
    }
  else
    {
      /* Construct a DW_CFA_def_cfa_expression instruction to
         calculate the CFA using a full location expression since no
         register-offset pair is available.  */
      struct dw_loc_descr_struct *loc_list;

      cfi->dw_cfi_opc = DW_CFA_def_cfa_expression;
      loc_list = build_cfa_loc (&loc);
      cfi->dw_cfi_oprnd1.dw_cfi_loc = loc_list;
    }

  add_fde_cfi (label, cfi);
}

/* Add the CFI for saving a register.  REG is the CFA column number.
   LABEL is passed to add_fde_cfi.
   If SREG is -1, the register is saved at OFFSET from the CFA;
   otherwise it is saved in SREG.  */

static void
reg_save (const char *label, unsigned int reg, unsigned int sreg, HOST_WIDE_INT offset)
{
  dw_cfi_ref cfi = new_cfi ();

  cfi->dw_cfi_oprnd1.dw_cfi_reg_num = reg;

  if (sreg == INVALID_REGNUM)
    {
      if (reg & ~0x3f)
        /* The register number won't fit in 6 bits, so we have to use
           the long form.  */
        cfi->dw_cfi_opc = DW_CFA_offset_extended;
      else
        cfi->dw_cfi_opc = DW_CFA_offset;

#ifdef ENABLE_CHECKING
      {
        /* If we get an offset that is not a multiple of
           DWARF_CIE_DATA_ALIGNMENT, there is either a bug in the
           definition of DWARF_CIE_DATA_ALIGNMENT, or a bug in the machine
           description.  */
        HOST_WIDE_INT check_offset = offset / DWARF_CIE_DATA_ALIGNMENT;

        gcc_assert (check_offset * DWARF_CIE_DATA_ALIGNMENT == offset);
      }
#endif
      offset /= DWARF_CIE_DATA_ALIGNMENT;
      if (offset < 0)
        cfi->dw_cfi_opc = DW_CFA_offset_extended_sf;

      cfi->dw_cfi_oprnd2.dw_cfi_offset = offset;
    }
  else if (sreg == reg)
    cfi->dw_cfi_opc = DW_CFA_same_value;
  else
    {
      cfi->dw_cfi_opc = DW_CFA_register;
      cfi->dw_cfi_oprnd2.dw_cfi_reg_num = sreg;
    }

  add_fde_cfi (label, cfi);
}

/* Add the CFI for saving a register window.  LABEL is passed to reg_save.
   This CFI tells the unwinder that it needs to restore the window registers
   from the previous frame's window save area.

   ??? Perhaps we should note in the CIE where windows are saved (instead of
   assuming 0(cfa)) and what registers are in the window.  */

void
dwarf2out_window_save (const char *label)
{
  dw_cfi_ref cfi = new_cfi ();

  cfi->dw_cfi_opc = DW_CFA_GNU_window_save;
  add_fde_cfi (label, cfi);
}

/* Add a CFI to update the running total of the size of arguments
   pushed onto the stack.  */

void
dwarf2out_args_size (const char *label, HOST_WIDE_INT size)
{
  dw_cfi_ref cfi;

  if (size == old_args_size)
    return;

  old_args_size = size;

  cfi = new_cfi ();
  cfi->dw_cfi_opc = DW_CFA_GNU_args_size;
  cfi->dw_cfi_oprnd1.dw_cfi_offset = size;
  add_fde_cfi (label, cfi);
}

/* Entry point for saving a register to the stack.  REG is the GCC register
   number.  LABEL and OFFSET are passed to reg_save.  */

void
dwarf2out_reg_save (const char *label, unsigned int reg, HOST_WIDE_INT offset)
{
  reg_save (label, DWARF_FRAME_REGNUM (reg), INVALID_REGNUM, offset);
}

/* Entry point for saving the return address in the stack.
   LABEL and OFFSET are passed to reg_save.  */

void
dwarf2out_return_save (const char *label, HOST_WIDE_INT offset)
{
  reg_save (label, DWARF_FRAME_RETURN_COLUMN, INVALID_REGNUM, offset);
}

/* Entry point for saving the return address in a register.
   LABEL and SREG are passed to reg_save.  */

void
dwarf2out_return_reg (const char *label, unsigned int sreg)
{
  reg_save (label, DWARF_FRAME_RETURN_COLUMN, DWARF_FRAME_REGNUM (sreg), 0);
}

/* Record the initial position of the return address.  RTL is
   INCOMING_RETURN_ADDR_RTX.  */

static void
initial_return_save (rtx rtl)
{
  unsigned int reg = INVALID_REGNUM;
  HOST_WIDE_INT offset = 0;

  switch (GET_CODE (rtl))
    {
    case REG:
      /* RA is in a register.  */
      reg = DWARF_FRAME_REGNUM (REGNO (rtl));
      break;

    case MEM:
      /* RA is on the stack.  */
      rtl = XEXP (rtl, 0);
      switch (GET_CODE (rtl))
        {
        case REG:
          gcc_assert (REGNO (rtl) == STACK_POINTER_REGNUM);
          offset = 0;
          break;

        case PLUS:
          gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
          offset = INTVAL (XEXP (rtl, 1));
          break;

        case MINUS:
          gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
          offset = -INTVAL (XEXP (rtl, 1));
          break;

        default:
          gcc_unreachable ();
        }

      break;

    case PLUS:
      /* The return address is at some offset from any value we can
         actually load.  For instance, on the SPARC it is in %i7+8. Just
         ignore the offset for now; it doesn't matter for unwinding frames.  */
      gcc_assert (GET_CODE (XEXP (rtl, 1)) == CONST_INT);
      initial_return_save (XEXP (rtl, 0));
      return;

    default:
      gcc_unreachable ();
    }

  if (reg != DWARF_FRAME_RETURN_COLUMN)
    reg_save (NULL, DWARF_FRAME_RETURN_COLUMN, reg, offset - cfa.offset);
}

/* Given a SET, calculate the amount of stack adjustment it
   contains.  */

static HOST_WIDE_INT
stack_adjust_offset (rtx pattern)
{
  rtx src = SET_SRC (pattern);
  rtx dest = SET_DEST (pattern);
  HOST_WIDE_INT offset = 0;
  enum rtx_code code;

  if (dest == stack_pointer_rtx)
    {
      /* (set (reg sp) (plus (reg sp) (const_int))) */
      code = GET_CODE (src);
      if (! (code == PLUS || code == MINUS)
          || XEXP (src, 0) != stack_pointer_rtx
          || GET_CODE (XEXP (src, 1)) != CONST_INT)
        return 0;

      offset = INTVAL (XEXP (src, 1));
      if (code == PLUS)
        offset = -offset;
    }
  else if (MEM_P (dest))
    {
      /* (set (mem (pre_dec (reg sp))) (foo)) */
      src = XEXP (dest, 0);
      code = GET_CODE (src);

      switch (code)
        {
        case PRE_MODIFY:
        case POST_MODIFY:
          if (XEXP (src, 0) == stack_pointer_rtx)
            {
              rtx val = XEXP (XEXP (src, 1), 1);
              /* We handle only adjustments by constant amount.  */
              gcc_assert (GET_CODE (XEXP (src, 1)) == PLUS
                          && GET_CODE (val) == CONST_INT);
              offset = -INTVAL (val);
              break;
            }
          return 0;

        case PRE_DEC:
        case POST_DEC:
          if (XEXP (src, 0) == stack_pointer_rtx)
            {
              offset = GET_MODE_SIZE (GET_MODE (dest));
              break;
            }
          return 0;

        case PRE_INC:
        case POST_INC:
          if (XEXP (src, 0) == stack_pointer_rtx)
            {
              offset = -GET_MODE_SIZE (GET_MODE (dest));
              break;
            }
          return 0;

        default:
          return 0;
        }
    }
  else
    return 0;

  return offset;
}

/* Check INSN to see if it looks like a push or a stack adjustment, and
   make a note of it if it does.  EH uses this information to find out how
   much extra space it needs to pop off the stack.  */

static void
dwarf2out_stack_adjust (rtx insn, bool after_p)
{
  HOST_WIDE_INT offset;
  const char *label;
  int i;

  /* Don't handle epilogues at all.  Certainly it would be wrong to do so
     with this function.  Proper support would require all frame-related
     insns to be marked, and to be able to handle saving state around
     epilogues textually in the middle of the function.  */
  if (prologue_epilogue_contains (insn) || sibcall_epilogue_contains (insn))
    return;

  /* If only calls can throw, and we have a frame pointer,
     save up adjustments until we see the CALL_INSN.  */
  if (!flag_asynchronous_unwind_tables && cfa.reg != STACK_POINTER_REGNUM)
    {
      if (CALL_P (insn) && !after_p)
        {
          /* Extract the size of the args from the CALL rtx itself.  */
          insn = PATTERN (insn);
          if (GET_CODE (insn) == PARALLEL)
            insn = XVECEXP (insn, 0, 0);
          if (GET_CODE (insn) == SET)
            insn = SET_SRC (insn);
          gcc_assert (GET_CODE (insn) == CALL);
          dwarf2out_args_size ("", INTVAL (XEXP (insn, 1)));
        }
      return;
    }

  if (CALL_P (insn) && !after_p)
    {
      if (!flag_asynchronous_unwind_tables)
        dwarf2out_args_size ("", args_size);
      return;
    }
  else if (BARRIER_P (insn))
    {
      /* When we see a BARRIER, we know to reset args_size to 0.  Usually
         the compiler will have already emitted a stack adjustment, but
         doesn't bother for calls to noreturn functions.  */
#ifdef STACK_GROWS_DOWNWARD
      offset = -args_size;
#else
      offset = args_size;
#endif
    }
  else if (GET_CODE (PATTERN (insn)) == SET)
    offset = stack_adjust_offset (PATTERN (insn));
  else if (GET_CODE (PATTERN (insn)) == PARALLEL
           || GET_CODE (PATTERN (insn)) == SEQUENCE)
    {
      /* There may be stack adjustments inside compound insns.  Search
         for them.  */
      for (offset = 0, i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
        if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET)
          offset += stack_adjust_offset (XVECEXP (PATTERN (insn), 0, i));
    }
  else
    return;

  if (offset == 0)
    return;

  if (cfa.reg == STACK_POINTER_REGNUM)
    cfa.offset += offset;

#ifndef STACK_GROWS_DOWNWARD
  offset = -offset;
#endif

  args_size += offset;
  if (args_size < 0)
    args_size = 0;

  label = dwarf2out_cfi_label ();
  def_cfa_1 (label, &cfa);
  if (flag_asynchronous_unwind_tables)
    dwarf2out_args_size (label, args_size);
}

#endif

/* We delay emitting a register save until either (a) we reach the end
   of the prologue or (b) the register is clobbered.  This clusters
   register saves so that there are fewer pc advances.  */

struct queued_reg_save GTY(())
{
  struct queued_reg_save *next;
  rtx reg;
  HOST_WIDE_INT cfa_offset;
  rtx saved_reg;
};

static GTY(()) struct queued_reg_save *queued_reg_saves;

/* The caller's ORIG_REG is saved in SAVED_IN_REG.  */
struct reg_saved_in_data GTY(()) {
  rtx orig_reg;
  rtx saved_in_reg;
};

/* A list of registers saved in other registers.
   The list intentionally has a small maximum capacity of 4; if your
   port needs more than that, you might consider implementing a
   more efficient data structure.  */
static GTY(()) struct reg_saved_in_data regs_saved_in_regs[4];
static GTY(()) size_t num_regs_saved_in_regs;

#if defined (DWARF2_DEBUGGING_INFO) || defined (DWARF2_UNWIND_INFO)
static const char *last_reg_save_label;

/* Add an entry to QUEUED_REG_SAVES saying that REG is now saved at
   SREG, or if SREG is NULL then it is saved at OFFSET to the CFA.  */

static void
queue_reg_save (const char *label, rtx reg, rtx sreg, HOST_WIDE_INT offset)
{
  struct queued_reg_save *q;

  /* Duplicates waste space, but it's also necessary to remove them
     for correctness, since the queue gets output in reverse
     order.  */
  for (q = queued_reg_saves; q != NULL; q = q->next)
    if (REGNO (q->reg) == REGNO (reg))
      break;

  if (q == NULL)
    {
      q = ggc_alloc (sizeof (*q));
      q->next = queued_reg_saves;
      queued_reg_saves = q;
    }

  q->reg = reg;
  q->cfa_offset = offset;
  q->saved_reg = sreg;

  last_reg_save_label = label;
}

/* Output all the entries in QUEUED_REG_SAVES.  */

static void
flush_queued_reg_saves (void)
{
  struct queued_reg_save *q;

  for (q = queued_reg_saves; q; q = q->next)
    {
      size_t i;
      unsigned int reg, sreg;

      for (i = 0; i < num_regs_saved_in_regs; i++)
        if (REGNO (regs_saved_in_regs[i].orig_reg) == REGNO (q->reg))
          break;
      if (q->saved_reg && i == num_regs_saved_in_regs)
        {
          gcc_assert (i != ARRAY_SIZE (regs_saved_in_regs));
          num_regs_saved_in_regs++;
        }
      if (i != num_regs_saved_in_regs)
        {
          regs_saved_in_regs[i].orig_reg = q->reg;
          regs_saved_in_regs[i].saved_in_reg = q->saved_reg;
        }

      reg = DWARF_FRAME_REGNUM (REGNO (q->reg));
      if (q->saved_reg)
        sreg = DWARF_FRAME_REGNUM (REGNO (q->saved_reg));
      else
        sreg = INVALID_REGNUM;
      reg_save (last_reg_save_label, reg, sreg, q->cfa_offset);
    }

  queued_reg_saves = NULL;
  last_reg_save_label = NULL;
}

/* Does INSN clobber any register which QUEUED_REG_SAVES lists a saved
   location for?  Or, does it clobber a register which we've previously
   said that some other register is saved in, and for which we now
   have a new location for?  */

static bool
clobbers_queued_reg_save (rtx insn)
{
  struct queued_reg_save *q;

  for (q = queued_reg_saves; q; q = q->next)
    {
      size_t i;
      if (modified_in_p (q->reg, insn))
        return true;
      for (i = 0; i < num_regs_saved_in_regs; i++)
        if (REGNO (q->reg) == REGNO (regs_saved_in_regs[i].orig_reg)
            && modified_in_p (regs_saved_in_regs[i].saved_in_reg, insn))
          return true;
    }

  return false;
}

/* What register, if any, is currently saved in REG?  */

static rtx
reg_saved_in (rtx reg)
{
  unsigned int regn = REGNO (reg);
  size_t i;
  struct queued_reg_save *q;

  for (q = queued_reg_saves; q; q = q->next)
    if (q->saved_reg && regn == REGNO (q->saved_reg))
      return q->reg;

  for (i = 0; i < num_regs_saved_in_regs; i++)
    if (regs_saved_in_regs[i].saved_in_reg
        && regn == REGNO (regs_saved_in_regs[i].saved_in_reg))
      return regs_saved_in_regs[i].orig_reg;

  return NULL_RTX;
}


/* A temporary register holding an integral value used in adjusting SP
   or setting up the store_reg.  The "offset" field holds the integer
   value, not an offset.  */
static dw_cfa_location cfa_temp;

/* Record call frame debugging information for an expression EXPR,
   which either sets SP or FP (adjusting how we calculate the frame
   address) or saves a register to the stack or another register.
   LABEL indicates the address of EXPR.

   This function encodes a state machine mapping rtxes to actions on
   cfa, cfa_store, and cfa_temp.reg.  We describe these rules so
   users need not read the source code.

  The High-Level Picture

  Changes in the register we use to calculate the CFA: Currently we
  assume that if you copy the CFA register into another register, we
  should take the other one as the new CFA register; this seems to
  work pretty well.  If it's wrong for some target, it's simple
  enough not to set RTX_FRAME_RELATED_P on the insn in question.

  Changes in the register we use for saving registers to the stack:
  This is usually SP, but not always.  Again, we deduce that if you
  copy SP into another register (and SP is not the CFA register),
  then the new register is the one we will be using for register
  saves.  This also seems to work.

  Register saves: There's not much guesswork about this one; if
  RTX_FRAME_RELATED_P is set on an insn which modifies memory, it's a
  register save, and the register used to calculate the destination
  had better be the one we think we're using for this purpose.
  It's also assumed that a copy from a call-saved register to another
  register is saving that register if RTX_FRAME_RELATED_P is set on
  that instruction.  If the copy is from a call-saved register to
  the *same* register, that means that the register is now the same
  value as in the caller.

  Except: If the register being saved is the CFA register, and the
  offset is nonzero, we are saving the CFA, so we assume we have to
  use DW_CFA_def_cfa_expression.  If the offset is 0, we assume that
  the intent is to save the value of SP from the previous frame.

  In addition, if a register has previously been saved to a different
  register,

  Invariants / Summaries of Rules

  cfa          current rule for calculating the CFA.  It usually
               consists of a register and an offset.
  cfa_store    register used by prologue code to save things to the stack
               cfa_store.offset is the offset from the value of
               cfa_store.reg to the actual CFA
  cfa_temp     register holding an integral value.  cfa_temp.offset
               stores the value, which will be used to adjust the
               stack pointer.  cfa_temp is also used like cfa_store,
               to track stores to the stack via fp or a temp reg.

  Rules  1- 4: Setting a register's value to cfa.reg or an expression
               with cfa.reg as the first operand changes the cfa.reg and its
               cfa.offset.  Rule 1 and 4 also set cfa_temp.reg and
               cfa_temp.offset.

  Rules  6- 9: Set a non-cfa.reg register value to a constant or an
               expression yielding a constant.  This sets cfa_temp.reg
               and cfa_temp.offset.

  Rule 5:      Create a new register cfa_store used to save items to the
               stack.

  Rules 10-14: Save a register to the stack.  Define offset as the
               difference of the original location and cfa_store's
               location (or cfa_temp's location if cfa_temp is used).

  The Rules

  "{a,b}" indicates a choice of a xor b.
  "<reg>:cfa.reg" indicates that <reg> must equal cfa.reg.

  Rule 1:
  (set <reg1> <reg2>:cfa.reg)
  effects: cfa.reg = <reg1>
           cfa.offset unchanged
           cfa_temp.reg = <reg1>
           cfa_temp.offset = cfa.offset

  Rule 2:
  (set sp ({minus,plus,losum} {sp,fp}:cfa.reg
                              {<const_int>,<reg>:cfa_temp.reg}))
  effects: cfa.reg = sp if fp used
           cfa.offset += {+/- <const_int>, cfa_temp.offset} if cfa.reg==sp
           cfa_store.offset += {+/- <const_int>, cfa_temp.offset}
             if cfa_store.reg==sp

  Rule 3:
  (set fp ({minus,plus,losum} <reg>:cfa.reg <const_int>))
  effects: cfa.reg = fp
           cfa_offset += +/- <const_int>

  Rule 4:
  (set <reg1> ({plus,losum} <reg2>:cfa.reg <const_int>))
  constraints: <reg1> != fp
               <reg1> != sp
  effects: cfa.reg = <reg1>
           cfa_temp.reg = <reg1>
           cfa_temp.offset = cfa.offset

  Rule 5:
  (set <reg1> (plus <reg2>:cfa_temp.reg sp:cfa.reg))
  constraints: <reg1> != fp
               <reg1> != sp
  effects: cfa_store.reg = <reg1>
           cfa_store.offset = cfa.offset - cfa_temp.offset

  Rule 6:
  (set <reg> <const_int>)
  effects: cfa_temp.reg = <reg>
           cfa_temp.offset = <const_int>

  Rule 7:
  (set <reg1>:cfa_temp.reg (ior <reg2>:cfa_temp.reg <const_int>))
  effects: cfa_temp.reg = <reg1>
           cfa_temp.offset |= <const_int>

  Rule 8:
  (set <reg> (high <exp>))
  effects: none

  Rule 9:
  (set <reg> (lo_sum <exp> <const_int>))
  effects: cfa_temp.reg = <reg>
           cfa_temp.offset = <const_int>

  Rule 10:
  (set (mem (pre_modify sp:cfa_store (???? <reg1> <const_int>))) <reg2>)
  effects: cfa_store.offset -= <const_int>
           cfa.offset = cfa_store.offset if cfa.reg == sp
           cfa.reg = sp
           cfa.base_offset = -cfa_store.offset

  Rule 11:
  (set (mem ({pre_inc,pre_dec} sp:cfa_store.reg)) <reg>)
  effects: cfa_store.offset += -/+ mode_size(mem)
           cfa.offset = cfa_store.offset if cfa.reg == sp
           cfa.reg = sp
           cfa.base_offset = -cfa_store.offset

  Rule 12:
  (set (mem ({minus,plus,losum} <reg1>:{cfa_store,cfa_temp} <const_int>))

       <reg2>)
  effects: cfa.reg = <reg1>
           cfa.base_offset = -/+ <const_int> - {cfa_store,cfa_temp}.offset

  Rule 13:
  (set (mem <reg1>:{cfa_store,cfa_temp}) <reg2>)
  effects: cfa.reg = <reg1>
           cfa.base_offset = -{cfa_store,cfa_temp}.offset

  Rule 14:
  (set (mem (postinc <reg1>:cfa_temp <const_int>)) <reg2>)
  effects: cfa.reg = <reg1>
           cfa.base_offset = -cfa_temp.offset
           cfa_temp.offset -= mode_size(mem)

  Rule 15:
  (set <reg> {unspec, unspec_volatile})
  effects: target-dependent  */

static void
dwarf2out_frame_debug_expr (rtx expr, const char *label)
{
  rtx src, dest;
  HOST_WIDE_INT offset;

  /* If RTX_FRAME_RELATED_P is set on a PARALLEL, process each member of
     the PARALLEL independently. The first element is always processed if
     it is a SET. This is for backward compatibility.   Other elements
     are processed only if they are SETs and the RTX_FRAME_RELATED_P
     flag is set in them.  */
  if (GET_CODE (expr) == PARALLEL || GET_CODE (expr) == SEQUENCE)
    {
      int par_index;
      int limit = XVECLEN (expr, 0);

      for (par_index = 0; par_index < limit; par_index++)
        if (GET_CODE (XVECEXP (expr, 0, par_index)) == SET
            && (RTX_FRAME_RELATED_P (XVECEXP (expr, 0, par_index))
                || par_index == 0))
          dwarf2out_frame_debug_expr (XVECEXP (expr, 0, par_index), label);

      return;
    }

  gcc_assert (GET_CODE (expr) == SET);

  src = SET_SRC (expr);
  dest = SET_DEST (expr);

  if (GET_CODE (src) == REG)
    {
      rtx rsi = reg_saved_in (src);
      if (rsi)
        src = rsi;
    }

  switch (GET_CODE (dest))
    {
    case REG:
      switch (GET_CODE (src))
        {
          /* Setting FP from SP.  */
        case REG:
          if (cfa.reg == (unsigned) REGNO (src))
            {
              /* Rule 1 */
              /* Update the CFA rule wrt SP or FP.  Make sure src is
                 relative to the current CFA register.

                 We used to require that dest be either SP or FP, but the
                 ARM copies SP to a temporary register, and from there to
                 FP.  So we just rely on the backends to only set
                 RTX_FRAME_RELATED_P on appropriate insns.  */
              cfa.reg = REGNO (dest);
              cfa_temp.reg = cfa.reg;
              cfa_temp.offset = cfa.offset;
            }
          else
            {
              /* Saving a register in a register.  */
              gcc_assert (call_used_regs [REGNO (dest)]
                          && (!fixed_regs [REGNO (dest)]
                              /* For the SPARC and its register window.  */
                              || DWARF_FRAME_REGNUM (REGNO (src))
                                   == DWARF_FRAME_RETURN_COLUMN));
              queue_reg_save (label, src, dest, 0);
            }
          break;

        case PLUS:
        case MINUS:
        case LO_SUM:
          if (dest == stack_pointer_rtx)
            {
              /* Rule 2 */
              /* Adjusting SP.  */
              switch (GET_CODE (XEXP (src, 1)))
                {
                case CONST_INT:
                  offset = INTVAL (XEXP (src, 1));
                  break;
                case REG:
                  gcc_assert ((unsigned) REGNO (XEXP (src, 1))
                              == cfa_temp.reg);
                  offset = cfa_temp.offset;
                  break;
                default:
                  gcc_unreachable ();
                }

              if (XEXP (src, 0) == hard_frame_pointer_rtx)
                {
                  /* Restoring SP from FP in the epilogue.  */
                  gcc_assert (cfa.reg == (unsigned) HARD_FRAME_POINTER_REGNUM);
                  cfa.reg = STACK_POINTER_REGNUM;
                }
              else if (GET_CODE (src) == LO_SUM)
                /* Assume we've set the source reg of the LO_SUM from sp.  */
                ;
              else
                gcc_assert (XEXP (src, 0) == stack_pointer_rtx);

              if (GET_CODE (src) != MINUS)
                offset = -offset;
              if (cfa.reg == STACK_POINTER_REGNUM)
                cfa.offset += offset;
              if (cfa_store.reg == STACK_POINTER_REGNUM)
                cfa_store.offset += offset;
            }
          else if (dest == hard_frame_pointer_rtx)
            {
              /* Rule 3 */
              /* Either setting the FP from an offset of the SP,
                 or adjusting the FP */
              gcc_assert (frame_pointer_needed);

              gcc_assert (REG_P (XEXP (src, 0))
                          && (unsigned) REGNO (XEXP (src, 0)) == cfa.reg
                          && GET_CODE (XEXP (src, 1)) == CONST_INT);
              offset = INTVAL (XEXP (src, 1));
              if (GET_CODE (src) != MINUS)
                offset = -offset;
              cfa.offset += offset;
              cfa.reg = HARD_FRAME_POINTER_REGNUM;
            }
          else
            {
              gcc_assert (GET_CODE (src) != MINUS);

              /* Rule 4 */
              if (REG_P (XEXP (src, 0))
                  && REGNO (XEXP (src, 0)) == cfa.reg
                  && GET_CODE (XEXP (src, 1)) == CONST_INT)
                {
                  /* Setting a temporary CFA register that will be copied
                     into the FP later on.  */
                  offset = - INTVAL (XEXP (src, 1));
                  cfa.offset += offset;
                  cfa.reg = REGNO (dest);
                  /* Or used to save regs to the stack.  */
                  cfa_temp.reg = cfa.reg;
                  cfa_temp.offset = cfa.offset;
                }

              /* Rule 5 */
              else if (REG_P (XEXP (src, 0))
                       && REGNO (XEXP (src, 0)) == cfa_temp.reg
                       && XEXP (src, 1) == stack_pointer_rtx)
                {
                  /* Setting a scratch register that we will use instead
                     of SP for saving registers to the stack.  */
                  gcc_assert (cfa.reg == STACK_POINTER_REGNUM);
                  cfa_store.reg = REGNO (dest);
                  cfa_store.offset = cfa.offset - cfa_temp.offset;
                }

              /* Rule 9 */
              else if (GET_CODE (src) == LO_SUM
                       && GET_CODE (XEXP (src, 1)) == CONST_INT)
                {
                  cfa_temp.reg = REGNO (dest);
                  cfa_temp.offset = INTVAL (XEXP (src, 1));
                }
              else
                gcc_unreachable ();
            }
          break;

          /* Rule 6 */
        case CONST_INT:
          cfa_temp.reg = REGNO (dest);
          cfa_temp.offset = INTVAL (src);
          break;

          /* Rule 7 */
        case IOR:
          gcc_assert (REG_P (XEXP (src, 0))
                      && (unsigned) REGNO (XEXP (src, 0)) == cfa_temp.reg
                      && GET_CODE (XEXP (src, 1)) == CONST_INT);

          if ((unsigned) REGNO (dest) != cfa_temp.reg)
            cfa_temp.reg = REGNO (dest);
          cfa_temp.offset |= INTVAL (XEXP (src, 1));
          break;

          /* Skip over HIGH, assuming it will be followed by a LO_SUM,
             which will fill in all of the bits.  */
          /* Rule 8 */
        case HIGH:
          break;

          /* Rule 15 */
        case UNSPEC:
        case UNSPEC_VOLATILE:
          gcc_assert (targetm.dwarf_handle_frame_unspec);
          targetm.dwarf_handle_frame_unspec (label, expr, XINT (src, 1));
          break;

        default:
          gcc_unreachable ();
        }

      def_cfa_1 (label, &cfa);
      break;

    case MEM:
      gcc_assert (REG_P (src));

      /* Saving a register to the stack.  Make sure dest is relative to the
         CFA register.  */
      switch (GET_CODE (XEXP (dest, 0)))
        {
          /* Rule 10 */
          /* With a push.  */
        case PRE_MODIFY:
          /* We can't handle variable size modifications.  */
          gcc_assert (GET_CODE (XEXP (XEXP (XEXP (dest, 0), 1), 1))
                      == CONST_INT);
          offset = -INTVAL (XEXP (XEXP (XEXP (dest, 0), 1), 1));

          gcc_assert (REGNO (XEXP (XEXP (dest, 0), 0)) == STACK_POINTER_REGNUM
                      && cfa_store.reg == STACK_POINTER_REGNUM);

          cfa_store.offset += offset;
          if (cfa.reg == STACK_POINTER_REGNUM)
            cfa.offset = cfa_store.offset;

          offset = -cfa_store.offset;
          break;

          /* Rule 11 */
        case PRE_INC:
        case PRE_DEC:
          offset = GET_MODE_SIZE (GET_MODE (dest));
          if (GET_CODE (XEXP (dest, 0)) == PRE_INC)
            offset = -offset;

          gcc_assert (REGNO (XEXP (XEXP (dest, 0), 0)) == STACK_POINTER_REGNUM
                      && cfa_store.reg == STACK_POINTER_REGNUM);

          cfa_store.offset += offset;
          if (cfa.reg == STACK_POINTER_REGNUM)
            cfa.offset = cfa_store.offset;

          offset = -cfa_store.offset;
          break;

          /* Rule 12 */
          /* With an offset.  */
        case PLUS:
        case MINUS:
        case LO_SUM:
          {
            int regno;

            gcc_assert (GET_CODE (XEXP (XEXP (dest, 0), 1)) == CONST_INT);
            offset = INTVAL (XEXP (XEXP (dest, 0), 1));
            if (GET_CODE (XEXP (dest, 0)) == MINUS)
              offset = -offset;

            regno = REGNO (XEXP (XEXP (dest, 0), 0));

            if (cfa_store.reg == (unsigned) regno)
              offset -= cfa_store.offset;
            else
              {
                gcc_assert (cfa_temp.reg == (unsigned) regno);
                offset -= cfa_temp.offset;
              }
          }
          break;

          /* Rule 13 */
          /* Without an offset.  */
        case REG:
          {
            int regno = REGNO (XEXP (dest, 0));

            if (cfa_store.reg == (unsigned) regno)
              offset = -cfa_store.offset;
            else
              {
                gcc_assert (cfa_temp.reg == (unsigned) regno);
                offset = -cfa_temp.offset;
              }
          }
          break;

          /* Rule 14 */
        case POST_INC:
          gcc_assert (cfa_temp.reg
                      == (unsigned) REGNO (XEXP (XEXP (dest, 0), 0)));
          offset = -cfa_temp.offset;
          cfa_temp.offset -= GET_MODE_SIZE (GET_MODE (dest));
          break;

        default:
          gcc_unreachable ();
        }

      if (REGNO (src) != STACK_POINTER_REGNUM
          && REGNO (src) != HARD_FRAME_POINTER_REGNUM
          && (unsigned) REGNO (src) == cfa.reg)
        {
          /* We're storing the current CFA reg into the stack.  */

          if (cfa.offset == 0)
            {
              /* If the source register is exactly the CFA, assume
                 we're saving SP like any other register; this happens
                 on the ARM.  */
              def_cfa_1 (label, &cfa);
              queue_reg_save (label, stack_pointer_rtx, NULL_RTX, offset);
              break;
            }
          else
            {
              /* Otherwise, we'll need to look in the stack to
                 calculate the CFA.  */
              rtx x = XEXP (dest, 0);

              if (!REG_P (x))
                x = XEXP (x, 0);
              gcc_assert (REG_P (x));

              cfa.reg = REGNO (x);
              cfa.base_offset = offset;
              cfa.indirect = 1;
              def_cfa_1 (label, &cfa);
              break;
            }
        }

      def_cfa_1 (label, &cfa);
      queue_reg_save (label, src, NULL_RTX, offset);
      break;

    default:
      gcc_unreachable ();
    }
}

/* Record call frame debugging information for INSN, which either
   sets SP or FP (adjusting how we calculate the frame address) or saves a
   register to the stack.  If INSN is NULL_RTX, initialize our state.

   If AFTER_P is false, we're being called before the insn is emitted,
   otherwise after.  Call instructions get invoked twice.  */

void
dwarf2out_frame_debug (rtx insn, bool after_p)
{
  const char *label;
  rtx src;

  if (insn == NULL_RTX)
    {
      size_t i;

      /* Flush any queued register saves.  */
      flush_queued_reg_saves ();

      /* Set up state for generating call frame debug info.  */
      lookup_cfa (&cfa);
      gcc_assert (cfa.reg
                  == (unsigned long)DWARF_FRAME_REGNUM (STACK_POINTER_REGNUM));

      cfa.reg = STACK_POINTER_REGNUM;
      cfa_store = cfa;
      cfa_temp.reg = -1;
      cfa_temp.offset = 0;

      for (i = 0; i < num_regs_saved_in_regs; i++)
        {
          regs_saved_in_regs[i].orig_reg = NULL_RTX;
          regs_saved_in_regs[i].saved_in_reg = NULL_RTX;
        }
      num_regs_saved_in_regs = 0;
      return;
    }

  if (!NONJUMP_INSN_P (insn) || clobbers_queued_reg_save (insn))
    flush_queued_reg_saves ();

  if (! RTX_FRAME_RELATED_P (insn))
    {
      if (!ACCUMULATE_OUTGOING_ARGS)
        dwarf2out_stack_adjust (insn, after_p);
      return;
    }

  label = dwarf2out_cfi_label ();
  src = find_reg_note (insn, REG_FRAME_RELATED_EXPR, NULL_RTX);
  if (src)
    insn = XEXP (src, 0);
  else
    insn = PATTERN (insn);

  dwarf2out_frame_debug_expr (insn, label);
}

#endif

/* Describe for the GTY machinery what parts of dw_cfi_oprnd1 are used.  */
static enum dw_cfi_oprnd_type dw_cfi_oprnd1_desc
 (enum dwarf_call_frame_info cfi);

static enum dw_cfi_oprnd_type
dw_cfi_oprnd1_desc (enum dwarf_call_frame_info cfi)
{
  switch (cfi)
    {
    case DW_CFA_nop:
    case DW_CFA_GNU_window_save:
      return dw_cfi_oprnd_unused;

    case DW_CFA_set_loc:
    case DW_CFA_advance_loc1:
    case DW_CFA_advance_loc2:
    case DW_CFA_advance_loc4:
    case DW_CFA_MIPS_advance_loc8:
      return dw_cfi_oprnd_addr;

    case DW_CFA_offset:
    case DW_CFA_offset_extended:
    case DW_CFA_def_cfa:
    case DW_CFA_offset_extended_sf:
    case DW_CFA_def_cfa_sf:
    case DW_CFA_restore_extended:
    case DW_CFA_undefined:
    case DW_CFA_same_value:
    case DW_CFA_def_cfa_register:
    case DW_CFA_register:
      return dw_cfi_oprnd_reg_num;

    case DW_CFA_def_cfa_offset:
    case DW_CFA_GNU_args_size:
    case DW_CFA_def_cfa_offset_sf:
      return dw_cfi_oprnd_offset;

    case DW_CFA_def_cfa_expression:
    case DW_CFA_expression:
      return dw_cfi_oprnd_loc;

    default:
      gcc_unreachable ();
    }
}

/* Describe for the GTY machinery what parts of dw_cfi_oprnd2 are used.  */
static enum dw_cfi_oprnd_type dw_cfi_oprnd2_desc
 (enum dwarf_call_frame_info cfi);

static enum dw_cfi_oprnd_type
dw_cfi_oprnd2_desc (enum dwarf_call_frame_info cfi)
{
  switch (cfi)
    {
    case DW_CFA_def_cfa:
    case DW_CFA_def_cfa_sf:
    case DW_CFA_offset:
    case DW_CFA_offset_extended_sf:
    case DW_CFA_offset_extended:
      return dw_cfi_oprnd_offset;

    case DW_CFA_register:
      return dw_cfi_oprnd_reg_num;

    default:
      return dw_cfi_oprnd_unused;
    }
}

#if defined (DWARF2_DEBUGGING_INFO) || defined (DWARF2_UNWIND_INFO)

/* Map register numbers held in the call frame info that gcc has
   collected using DWARF_FRAME_REGNUM to those that should be output in
   .debug_frame and .eh_frame.  */
#ifndef DWARF2_FRAME_REG_OUT
#define DWARF2_FRAME_REG_OUT(REGNO, FOR_EH) (REGNO)
#endif

/* Output a Call Frame Information opcode and its operand(s).  */

static void
output_cfi (dw_cfi_ref cfi, dw_fde_ref fde, int for_eh)
{
  unsigned long r;
  if (cfi->dw_cfi_opc == DW_CFA_advance_loc)
    dw2_asm_output_data (1, (cfi->dw_cfi_opc
                             | (cfi->dw_cfi_oprnd1.dw_cfi_offset & 0x3f)),
                         "DW_CFA_advance_loc " HOST_WIDE_INT_PRINT_HEX,
                         cfi->dw_cfi_oprnd1.dw_cfi_offset);
  else if (cfi->dw_cfi_opc == DW_CFA_offset)
    {
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
      dw2_asm_output_data (1, (cfi->dw_cfi_opc | (r & 0x3f)),
                           "DW_CFA_offset, column 0x%lx", r);
      dw2_asm_output_data_uleb128 (cfi->dw_cfi_oprnd2.dw_cfi_offset, NULL);
    }
  else if (cfi->dw_cfi_opc == DW_CFA_restore)
    {
      r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
      dw2_asm_output_data (1, (cfi->dw_cfi_opc | (r & 0x3f)),
                           "DW_CFA_restore, column 0x%lx", r);
    }
  else
    {
      dw2_asm_output_data (1, cfi->dw_cfi_opc,
                           "%s", dwarf_cfi_name (cfi->dw_cfi_opc));

      switch (cfi->dw_cfi_opc)
        {
        case DW_CFA_set_loc:
          if (for_eh)
            dw2_asm_output_encoded_addr_rtx (
                ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/1, /*global=*/0),
                gen_rtx_SYMBOL_REF (Pmode, cfi->dw_cfi_oprnd1.dw_cfi_addr),
                NULL);
          else
            dw2_asm_output_addr (DWARF2_ADDR_SIZE,
                                 cfi->dw_cfi_oprnd1.dw_cfi_addr, NULL);
          break;

        case DW_CFA_advance_loc1:
          dw2_asm_output_delta (1, cfi->dw_cfi_oprnd1.dw_cfi_addr,
                                fde->dw_fde_current_label, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_advance_loc2:
          dw2_asm_output_delta (2, cfi->dw_cfi_oprnd1.dw_cfi_addr,
                                fde->dw_fde_current_label, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_advance_loc4:
          dw2_asm_output_delta (4, cfi->dw_cfi_oprnd1.dw_cfi_addr,
                                fde->dw_fde_current_label, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_MIPS_advance_loc8:
          dw2_asm_output_delta (8, cfi->dw_cfi_oprnd1.dw_cfi_addr,
                                fde->dw_fde_current_label, NULL);
          fde->dw_fde_current_label = cfi->dw_cfi_oprnd1.dw_cfi_addr;
          break;

        case DW_CFA_offset_extended:
        case DW_CFA_def_cfa:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          dw2_asm_output_data_uleb128 (cfi->dw_cfi_oprnd2.dw_cfi_offset, NULL);
          break;

        case DW_CFA_offset_extended_sf:
        case DW_CFA_def_cfa_sf:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          dw2_asm_output_data_sleb128 (cfi->dw_cfi_oprnd2.dw_cfi_offset, NULL);
          break;

        case DW_CFA_restore_extended:
        case DW_CFA_undefined:
        case DW_CFA_same_value:
        case DW_CFA_def_cfa_register:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          break;

        case DW_CFA_register:
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd1.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          r = DWARF2_FRAME_REG_OUT (cfi->dw_cfi_oprnd2.dw_cfi_reg_num, for_eh);
          dw2_asm_output_data_uleb128 (r, NULL);
          break;

        case DW_CFA_def_cfa_offset:
        case DW_CFA_GNU_args_size:
          dw2_asm_output_data_uleb128 (cfi->dw_cfi_oprnd1.dw_cfi_offset, NULL);
          break;

        case DW_CFA_def_cfa_offset_sf:
          dw2_asm_output_data_sleb128 (cfi->dw_cfi_oprnd1.dw_cfi_offset, NULL);
          break;

        case DW_CFA_GNU_window_save:
          break;

        case DW_CFA_def_cfa_expression:
        case DW_CFA_expression:
          output_cfa_loc (cfi);
          break;

        case DW_CFA_GNU_negative_offset_extended:
          /* Obsoleted by DW_CFA_offset_extended_sf.  */
          gcc_unreachable ();

        default:
          break;
        }
    }
}

/* Output the call frame information used to record information
   that relates to calculating the frame pointer, and records the
   location of saved registers.  */

static void
output_call_frame_info (int for_eh)
{
  unsigned int i;
  dw_fde_ref fde;
  dw_cfi_ref cfi;
  char l1[20], l2[20], section_start_label[20];
  bool any_lsda_needed = false;
  char augmentation[6];
  int augmentation_size;
  int fde_encoding = DW_EH_PE_absptr;
  int per_encoding = DW_EH_PE_absptr;
  int lsda_encoding = DW_EH_PE_absptr;

  /* Don't emit a CIE if there won't be any FDEs.  */
  if (fde_table_in_use == 0)
    return;

  /* If we make FDEs linkonce, we may have to emit an empty label for
     an FDE that wouldn't otherwise be emitted.  We want to avoid
     having an FDE kept around when the function it refers to is
     discarded.  Example where this matters: a primary function
     template in C++ requires EH information, but an explicit
     specialization doesn't.  */
  if (TARGET_USES_WEAK_UNWIND_INFO
      && ! flag_asynchronous_unwind_tables
      && for_eh)
    for (i = 0; i < fde_table_in_use; i++)
      if ((fde_table[i].nothrow || fde_table[i].all_throwers_are_sibcalls)
          && !fde_table[i].uses_eh_lsda
          && ! DECL_WEAK (fde_table[i].decl))
        targetm.asm_out.unwind_label (asm_out_file, fde_table[i].decl,
                                      for_eh, /* empty */ 1);

  /* If we don't have any functions we'll want to unwind out of, don't
     emit any EH unwind information.  Note that if exceptions aren't
     enabled, we won't have collected nothrow information, and if we
     asked for asynchronous tables, we always want this info.  */
  if (for_eh)
    {
      bool any_eh_needed = !flag_exceptions || flag_asynchronous_unwind_tables;

      for (i = 0; i < fde_table_in_use; i++)
        if (fde_table[i].uses_eh_lsda)
          any_eh_needed = any_lsda_needed = true;
        else if (TARGET_USES_WEAK_UNWIND_INFO && DECL_WEAK (fde_table[i].decl))
          any_eh_needed = true;
        else if (! fde_table[i].nothrow
                 && ! fde_table[i].all_throwers_are_sibcalls)
          any_eh_needed = true;

      if (! any_eh_needed)
        return;
    }

  /* We're going to be generating comments, so turn on app.  */
  if (flag_debug_asm)
    app_enable ();

  if (for_eh)
    targetm.asm_out.eh_frame_section ();
  else
    named_section_flags (DEBUG_FRAME_SECTION, SECTION_DEBUG);

  ASM_GENERATE_INTERNAL_LABEL (section_start_label, FRAME_BEGIN_LABEL, for_eh);
  ASM_OUTPUT_LABEL (asm_out_file, section_start_label);

  /* Output the CIE.  */
  ASM_GENERATE_INTERNAL_LABEL (l1, CIE_AFTER_SIZE_LABEL, for_eh);
  ASM_GENERATE_INTERNAL_LABEL (l2, CIE_END_LABEL, for_eh);
  dw2_asm_output_delta (for_eh ? 4 : DWARF_OFFSET_SIZE, l2, l1,
                        "Length of Common Information Entry");
  ASM_OUTPUT_LABEL (asm_out_file, l1);

  /* Now that the CIE pointer is PC-relative for EH,
     use 0 to identify the CIE.  */
  dw2_asm_output_data ((for_eh ? 4 : DWARF_OFFSET_SIZE),
                       (for_eh ? 0 : DW_CIE_ID),
                       "CIE Identifier Tag");

  dw2_asm_output_data (1, DW_CIE_VERSION, "CIE Version");

  augmentation[0] = 0;
  augmentation_size = 0;
  if (for_eh)
    {
      char *p;

      /* Augmentation:
         z      Indicates that a uleb128 is present to size the
                augmentation section.
         L      Indicates the encoding (and thus presence) of
                an LSDA pointer in the FDE augmentation.
         R      Indicates a non-default pointer encoding for
                FDE code pointers.
         P      Indicates the presence of an encoding + language
                personality routine in the CIE augmentation.  */

      fde_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/1, /*global=*/0);
      per_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/2, /*global=*/1);
      lsda_encoding = ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0, /*global=*/0);

      p = augmentation + 1;
      if (eh_personality_libfunc)
        {
          *p++ = 'P';
          augmentation_size += 1 + size_of_encoded_value (per_encoding);
        }
      if (any_lsda_needed)
        {
          *p++ = 'L';
          augmentation_size += 1;
        }
      if (fde_encoding != DW_EH_PE_absptr)
        {
          *p++ = 'R';
          augmentation_size += 1;
        }
      if (p > augmentation + 1)
        {
          augmentation[0] = 'z';
          *p = '\0';
        }

      /* Ug.  Some platforms can't do unaligned dynamic relocations at all.  */
      if (eh_personality_libfunc && per_encoding == DW_EH_PE_aligned)
        {
          int offset = (  4             /* Length */
                        + 4             /* CIE Id */
                        + 1             /* CIE version */
                        + strlen (augmentation) + 1     /* Augmentation */
                        + size_of_uleb128 (1)           /* Code alignment */
                        + size_of_sleb128 (DWARF_CIE_DATA_ALIGNMENT)
                        + 1             /* RA column */
                        + 1             /* Augmentation size */
                        + 1             /* Personality encoding */ );
          int pad = -offset & (PTR_SIZE - 1);

          augmentation_size += pad;

          /* Augmentations should be small, so there's scarce need to
             iterate for a solution.  Die if we exceed one uleb128 byte.  */
          gcc_assert (size_of_uleb128 (augmentation_size) == 1);
        }
    }

  dw2_asm_output_nstring (augmentation, -1, "CIE Augmentation");
  dw2_asm_output_data_uleb128 (1, "CIE Code Alignment Factor");
  dw2_asm_output_data_sleb128 (DWARF_CIE_DATA_ALIGNMENT,
                               "CIE Data Alignment Factor");

  if (DW_CIE_VERSION == 1)
    dw2_asm_output_data (1, DWARF_FRAME_RETURN_COLUMN, "CIE RA Column");
  else
    dw2_asm_output_data_uleb128 (DWARF_FRAME_RETURN_COLUMN, "CIE RA Column");

  if (augmentation[0])
    {
      dw2_asm_output_data_uleb128 (augmentation_size, "Augmentation size");
      if (eh_personality_libfunc)
        {
          dw2_asm_output_data (1, per_encoding, "Personality (%s)",
                               eh_data_format_name (per_encoding));
          dw2_asm_output_encoded_addr_rtx (per_encoding,
                                           eh_personality_libfunc, NULL);
        }

      if (any_lsda_needed)
        dw2_asm_output_data (1, lsda_encoding, "LSDA Encoding (%s)",
                             eh_data_format_name (lsda_encoding));

      if (fde_encoding != DW_EH_PE_absptr)
        dw2_asm_output_data (1, fde_encoding, "FDE Encoding (%s)",
                             eh_data_format_name (fde_encoding));
    }

  for (cfi = cie_cfi_head; cfi != NULL; cfi = cfi->dw_cfi_next)
    output_cfi (cfi, NULL, for_eh);

  /* Pad the CIE out to an address sized boundary.  */
  ASM_OUTPUT_ALIGN (asm_out_file,
                    floor_log2 (for_eh ? PTR_SIZE : DWARF2_ADDR_SIZE));
  ASM_OUTPUT_LABEL (asm_out_file, l2);

  /* Loop through all of the FDE's.  */
  for (i = 0; i < fde_table_in_use; i++)
    {
      fde = &fde_table[i];

      /* Don't emit EH unwind info for leaf functions that don't need it.  */
      if (for_eh && !flag_asynchronous_unwind_tables && flag_exceptions
          && (fde->nothrow || fde->all_throwers_are_sibcalls)
          && ! (TARGET_USES_WEAK_UNWIND_INFO && DECL_WEAK (fde_table[i].decl))
          && !fde->uses_eh_lsda)
        continue;

      targetm.asm_out.unwind_label (asm_out_file, fde->decl, for_eh, /* empty */ 0);
      targetm.asm_out.internal_label (asm_out_file, FDE_LABEL, for_eh + i * 2);
      ASM_GENERATE_INTERNAL_LABEL (l1, FDE_AFTER_SIZE_LABEL, for_eh + i * 2);
      ASM_GENERATE_INTERNAL_LABEL (l2, FDE_END_LABEL, for_eh + i * 2);
      dw2_asm_output_delta (for_eh ? 4 : DWARF_OFFSET_SIZE, l2, l1,
                            "FDE Length");
      ASM_OUTPUT_LABEL (asm_out_file, l1);

      if (for_eh)
        dw2_asm_output_delta (4, l1, section_start_label, "FDE CIE offset");
      else
        dw2_asm_output_offset (DWARF_OFFSET_SIZE, section_start_label,
                               "FDE CIE offset");

      if (for_eh)
        {
          rtx sym_ref = gen_rtx_SYMBOL_REF (Pmode, fde->dw_fde_begin);
          SYMBOL_REF_FLAGS (sym_ref) |= SYMBOL_FLAG_LOCAL;
          dw2_asm_output_encoded_addr_rtx (fde_encoding,
                                           sym_ref,
                                           "FDE initial location");
          dw2_asm_output_delta (size_of_encoded_value (fde_encoding),
                                fde->dw_fde_end, fde->dw_fde_begin,
                                "FDE address range");
        }
      else
        {
          dw2_asm_output_addr (DWARF2_ADDR_SIZE, fde->dw_fde_begin,
                               "FDE initial location");
          dw2_asm_output_delta (DWARF2_ADDR_SIZE,
                                fde->dw_fde_end, fde->dw_fde_begin,
                                "FDE address range");
        }

      if (augmentation[0])
        {
          if (any_lsda_needed)
            {
              int size = size_of_encoded_value (lsda_encoding);

              if (lsda_encoding == DW_EH_PE_aligned)
                {
                  int offset = (  4             /* Length */
                                + 4             /* CIE offset */
                                + 2 * size_of_encoded_value (fde_encoding)
                                + 1             /* Augmentation size */ );
                  int pad = -offset & (PTR_SIZE - 1);

                  size += pad;
                  gcc_assert (size_of_uleb128 (size) == 1);
                }

              dw2_asm_output_data_uleb128 (size, "Augmentation size");

              if (fde->uses_eh_lsda)
                {
                  ASM_GENERATE_INTERNAL_LABEL (l1, "LLSDA",
                                               fde->funcdef_number);
                  dw2_asm_output_encoded_addr_rtx (
                        lsda_encoding, gen_rtx_SYMBOL_REF (Pmode, l1),
                        "Language Specific Data Area");
                }
              else
                {
                  if (lsda_encoding == DW_EH_PE_aligned)
                    ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (PTR_SIZE));
                  dw2_asm_output_data
                    (size_of_encoded_value (lsda_encoding), 0,
                     "Language Specific Data Area (none)");
                }
            }
          else
            dw2_asm_output_data_uleb128 (0, "Augmentation size");
        }

      /* Loop through the Call Frame Instructions associated with
         this FDE.  */
      fde->dw_fde_current_label = fde->dw_fde_begin;
      for (cfi = fde->dw_fde_cfi; cfi != NULL; cfi = cfi->dw_cfi_next)
        output_cfi (cfi, fde, for_eh);

      /* Pad the FDE out to an address sized boundary.  */
      ASM_OUTPUT_ALIGN (asm_out_file,
                        floor_log2 ((for_eh ? PTR_SIZE : DWARF2_ADDR_SIZE)));
      ASM_OUTPUT_LABEL (asm_out_file, l2);
    }

  if (for_eh && targetm.terminate_dw2_eh_frame_info)
    dw2_asm_output_data (4, 0, "End of Table");
#ifdef MIPS_DEBUGGING_INFO
  /* Work around Irix 6 assembler bug whereby labels at the end of a section
     get a value of 0.  Putting .align 0 after the label fixes it.  */
  ASM_OUTPUT_ALIGN (asm_out_file, 0);
#endif

  /* Turn off app to make assembly quicker.  */
  if (flag_debug_asm)
    app_disable ();
}

/* Output a marker (i.e. a label) for the beginning of a function, before
   the prologue.  */

void
dwarf2out_begin_prologue (unsigned int line ATTRIBUTE_UNUSED,
                          const char *file ATTRIBUTE_UNUSED)
{
  char label[MAX_ARTIFICIAL_LABEL_BYTES];
  char * dup_label;
  dw_fde_ref fde;

  current_function_func_begin_label = NULL;

#ifdef TARGET_UNWIND_INFO
  /* ??? current_function_func_begin_label is also used by except.c
     for call-site information.  We must emit this label if it might
     be used.  */
  if ((! flag_exceptions || USING_SJLJ_EXCEPTIONS)
      && ! dwarf2out_do_frame ())
    return;
#else
  if (! dwarf2out_do_frame ())
    return;
#endif

  function_section (current_function_decl);
  ASM_GENERATE_INTERNAL_LABEL (label, FUNC_BEGIN_LABEL,
                               current_function_funcdef_no);
  ASM_OUTPUT_DEBUG_LABEL (asm_out_file, FUNC_BEGIN_LABEL,
                          current_function_funcdef_no);
  dup_label = xstrdup (label);
  current_function_func_begin_label = dup_label;

#ifdef TARGET_UNWIND_INFO
  /* We can elide the fde allocation if we're not emitting debug info.  */
  if (! dwarf2out_do_frame ())
    return;
#endif

  /* Expand the fde table if necessary.  */
  if (fde_table_in_use == fde_table_allocated)
    {
      fde_table_allocated += FDE_TABLE_INCREMENT;
      fde_table = ggc_realloc (fde_table,
                               fde_table_allocated * sizeof (dw_fde_node));
      memset (fde_table + fde_table_in_use, 0,
              FDE_TABLE_INCREMENT * sizeof (dw_fde_node));
    }

  /* Record the FDE associated with this function.  */
  current_funcdef_fde = fde_table_in_use;

  /* Add the new FDE at the end of the fde_table.  */
  fde = &fde_table[fde_table_in_use++];
  fde->decl = current_function_decl;
  fde->dw_fde_begin = dup_label;
  fde->dw_fde_current_label = NULL;
  fde->dw_fde_end = NULL;
  fde->dw_fde_cfi = NULL;
  fde->funcdef_number = current_function_funcdef_no;
  fde->nothrow = TREE_NOTHROW (current_function_decl);
  fde->uses_eh_lsda = cfun->uses_eh_lsda;
  fde->all_throwers_are_sibcalls = cfun->all_throwers_are_sibcalls;

  args_size = old_args_size = 0;

  /* We only want to output line number information for the genuine dwarf2
     prologue case, not the eh frame case.  */
#ifdef DWARF2_DEBUGGING_INFO
  if (file)
    dwarf2out_source_line (line, file);
#endif
}

/* Output a marker (i.e. a label) for the absolute end of the generated code
   for a function definition.  This gets called *after* the epilogue code has
   been generated.  */

void
dwarf2out_end_epilogue (unsigned int line ATTRIBUTE_UNUSED,
                        const char *file ATTRIBUTE_UNUSED)
{
  dw_fde_ref fde;
  char label[MAX_ARTIFICIAL_LABEL_BYTES];

  /* Output a label to mark the endpoint of the code generated for this
     function.  */
  ASM_GENERATE_INTERNAL_LABEL (label, FUNC_END_LABEL,
                               current_function_funcdef_no);
  ASM_OUTPUT_LABEL (asm_out_file, label);
  fde = &fde_table[fde_table_in_use - 1];
  fde->dw_fde_end = xstrdup (label);
}

void
dwarf2out_frame_init (void)
{
  /* Allocate the initial hunk of the fde_table.  */
  fde_table = ggc_alloc_cleared (FDE_TABLE_INCREMENT * sizeof (dw_fde_node));
  fde_table_allocated = FDE_TABLE_INCREMENT;
  fde_table_in_use = 0;

  /* Generate the CFA instructions common to all FDE's.  Do it now for the
     sake of lookup_cfa.  */

#ifdef DWARF2_UNWIND_INFO
  /* On entry, the Canonical Frame Address is at SP.  */
  dwarf2out_def_cfa (NULL, STACK_POINTER_REGNUM, INCOMING_FRAME_SP_OFFSET);
  initial_return_save (INCOMING_RETURN_ADDR_RTX);
#endif
}

void
dwarf2out_frame_finish (void)
{
  /* Output call frame information.  */
  if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
    output_call_frame_info (0);

#ifndef TARGET_UNWIND_INFO
  /* Output another copy for the unwinder.  */
  if (! USING_SJLJ_EXCEPTIONS && (flag_unwind_tables || flag_exceptions))
    output_call_frame_info (1);
#endif
}
#endif
\f
/* And now, the subset of the debugging information support code necessary
   for emitting location expressions.  */

/* We need some way to distinguish DW_OP_addr with a direct symbol
   relocation from DW_OP_addr with a dtp-relative symbol relocation.  */
#define INTERNAL_DW_OP_tls_addr         (0x100 + DW_OP_addr)


typedef struct dw_val_struct *dw_val_ref;
typedef struct die_struct *dw_die_ref;
typedef struct dw_loc_descr_struct *dw_loc_descr_ref;
typedef struct dw_loc_list_struct *dw_loc_list_ref;

/* Each DIE may have a series of attribute/value pairs.  Values
   can take on several forms.  The forms that are used in this
   implementation are listed below.  */

enum dw_val_class
{
  dw_val_class_addr,
  dw_val_class_offset,
  dw_val_class_loc,
  dw_val_class_loc_list,
  dw_val_class_range_list,
  dw_val_class_const,
  dw_val_class_unsigned_const,
  dw_val_class_long_long,
  dw_val_class_vec,
  dw_val_class_flag,
  dw_val_class_die_ref,
  dw_val_class_fde_ref,
  dw_val_class_lbl_id,
  dw_val_class_lbl_offset,
  dw_val_class_str
};

/* Describe a double word constant value.  */
/* ??? Every instance of long_long in the code really means CONST_DOUBLE.  */

typedef struct dw_long_long_struct GTY(())
{
  unsigned long hi;
  unsigned long low;
}
dw_long_long_const;

/* Describe a floating point constant value, or a vector constant value.  */

typedef struct dw_vec_struct GTY(())
{
  unsigned char * GTY((length ("%h.length"))) array;
  unsigned length;
  unsigned elt_size;
}
dw_vec_const;

/* The dw_val_node describes an attribute's value, as it is
   represented internally.  */

typedef struct dw_val_struct GTY(())
{
  enum dw_val_class val_class;
  union dw_val_struct_union
    {
      rtx GTY ((tag ("dw_val_class_addr"))) val_addr;
      unsigned HOST_WIDE_INT GTY ((tag ("dw_val_class_offset"))) val_offset;
      dw_loc_list_ref GTY ((tag ("dw_val_class_loc_list"))) val_loc_list;
      dw_loc_descr_ref GTY ((tag ("dw_val_class_loc"))) val_loc;
      HOST_WIDE_INT GTY ((default)) val_int;
      unsigned HOST_WIDE_INT GTY ((tag ("dw_val_class_unsigned_const"))) val_unsigned;
      dw_long_long_const GTY ((tag ("dw_val_class_long_long"))) val_long_long;
      dw_vec_const GTY ((tag ("dw_val_class_vec"))) val_vec;
      struct dw_val_die_union
        {
          dw_die_ref die;
          int external;
        } GTY ((tag ("dw_val_class_die_ref"))) val_die_ref;
      unsigned GTY ((tag ("dw_val_class_fde_ref"))) val_fde_index;
      struct indirect_string_node * GTY ((tag ("dw_val_class_str"))) val_str;
      char * GTY ((tag ("dw_val_class_lbl_id"))) val_lbl_id;
      unsigned char GTY ((tag ("dw_val_class_flag"))) val_flag;
    }
  GTY ((desc ("%1.val_class"))) v;
}
dw_val_node;

/* Locations in memory are described using a sequence of stack machine
   operations.  */

typedef struct dw_loc_descr_struct GTY(())
{
  dw_loc_descr_ref dw_loc_next;
  enum dwarf_location_atom dw_loc_opc;
  dw_val_node dw_loc_oprnd1;
  dw_val_node dw_loc_oprnd2;
  int dw_loc_addr;
}
dw_loc_descr_node;

/* Location lists are ranges + location descriptions for that range,
   so you can track variables that are in different places over
   their entire life.  */
typedef struct dw_loc_list_struct GTY(())
{
  dw_loc_list_ref dw_loc_next;
  const char *begin; /* Label for begin address of range */
  const char *end;  /* Label for end address of range */
  char *ll_symbol; /* Label for beginning of location list.
                      Only on head of list */
  const char *section; /* Section this loclist is relative to */
  dw_loc_descr_ref expr;
} dw_loc_list_node;

#if defined (DWARF2_DEBUGGING_INFO) || defined (DWARF2_UNWIND_INFO)

static const char *dwarf_stack_op_name (unsigned);
static dw_loc_descr_ref new_loc_descr (enum dwarf_location_atom,
                                       unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT);
static void add_loc_descr (dw_loc_descr_ref *, dw_loc_descr_ref);
static unsigned long size_of_loc_descr (dw_loc_descr_ref);
static unsigned long size_of_locs (dw_loc_descr_ref);
static void output_loc_operands (dw_loc_descr_ref);
static void output_loc_sequence (dw_loc_descr_ref);

/* Convert a DWARF stack opcode into its string name.  */

static const char *
dwarf_stack_op_name (unsigned int op)
{
  switch (op)
    {
    case DW_OP_addr:
    case INTERNAL_DW_OP_tls_addr:
      return "DW_OP_addr";
    case DW_OP_deref:
      return "DW_OP_deref";
    case DW_OP_const1u:
      return "DW_OP_const1u";
    case DW_OP_const1s:
      return "DW_OP_const1s";
    case DW_OP_const2u:
      return "DW_OP_const2u";
    case DW_OP_const2s:
      return "DW_OP_const2s";
    case DW_OP_const4u:
      return "DW_OP_const4u";
    case DW_OP_const4s:
      return "DW_OP_const4s";
    case DW_OP_const8u:
      return "DW_OP_const8u";
    case DW_OP_const8s:
      return "DW_OP_const8s";
    case DW_OP_constu:
      return "DW_OP_constu";
    case DW_OP_consts:
      return "DW_OP_consts";
    case DW_OP_dup:
      return "DW_OP_dup";
    case DW_OP_drop:
      return "DW_OP_drop";
    case DW_OP_over:
      return "DW_OP_over";
    case DW_OP_pick:
      return "DW_OP_pick";
    case DW_OP_swap:
      return "DW_OP_swap";
    case DW_OP_rot:
      return "DW_OP_rot";
    case DW_OP_xderef:
      return "DW_OP_xderef";
    case DW_OP_abs:
      return "DW_OP_abs";
    case DW_OP_and:
      return "DW_OP_and";
    case DW_OP_div:
      return "DW_OP_div";
    case DW_OP_minus:
      return "DW_OP_minus";
    case DW_OP_mod:
      return "DW_OP_mod";
    case DW_OP_mul:
      return "DW_OP_mul";
    case DW_OP_neg:
      return "DW_OP_neg";
    case DW_OP_not:
      return "DW_OP_not";
    case DW_OP_or:
      return "DW_OP_or";
    case DW_OP_plus:
      return "DW_OP_plus";
    case DW_OP_plus_uconst:
      return "DW_OP_plus_uconst";
    case DW_OP_shl:
      return "DW_OP_shl";
    case DW_OP_shr:
      return "DW_OP_shr";
    case DW_OP_shra:
      return "DW_OP_shra";
    case DW_OP_xor:
      return "DW_OP_xor";
    case DW_OP_bra:
      return "DW_OP_bra";
    case DW_OP_eq:
      return "DW_OP_eq";
    case DW_OP_ge:
      return "DW_OP_ge";
    case DW_OP_gt:
      return "DW_OP_gt";
    case DW_OP_le:
      return "DW_OP_le";
    case DW_OP_lt:
      return "DW_OP_lt";
    case DW_OP_ne:
      return "DW_OP_ne";
    case DW_OP_skip:
      return "DW_OP_skip";
    case DW_OP_lit0:
      return "DW_OP_lit0";
    case DW_OP_lit1:
      return "DW_OP_lit1";
    case DW_OP_lit2:
      return "DW_OP_lit2";
    case DW_OP_lit3:
      return "DW_OP_lit3";
    case DW_OP_lit4:
      return "DW_OP_lit4";
    case DW_OP_lit5:
      return "DW_OP_lit5";
    case DW_OP_lit6:
      return "DW_OP_lit6";
    case DW_OP_lit7:
      return "DW_OP_lit7";
    case DW_OP_lit8:
      return "DW_OP_lit8";
    case DW_OP_lit9:
      return "DW_OP_lit9";
    case DW_OP_lit10:
      return "DW_OP_lit10";
    case DW_OP_lit11:
      return "DW_OP_lit11";
    case DW_OP_lit12:
      return "DW_OP_lit12";
    case DW_OP_lit13:
      return "DW_OP_lit13";
    case DW_OP_lit14:
      return "DW_OP_lit14";
    case DW_OP_lit15:
      return "DW_OP_lit15";
    case DW_OP_lit16:
      return "DW_OP_lit16";
    case DW_OP_lit17:
      return "DW_OP_lit17";
    case DW_OP_lit18:
      return "DW_OP_lit18";
    case DW_OP_lit19:
      return "DW_OP_lit19";
    case DW_OP_lit20:
      return "DW_OP_lit20";
    case DW_OP_lit21:
      return "DW_OP_lit21";
    case DW_OP_lit22:
      return "DW_OP_lit22";
    case DW_OP_lit23:
      return "DW_OP_lit23";
    case DW_OP_lit24:
      return "DW_OP_lit24";
    case DW_OP_lit25:
      return "DW_OP_lit25";
    case DW_OP_lit26:
      return "DW_OP_lit26";
    case DW_OP_lit27:
      return "DW_OP_lit27";
    case DW_OP_lit28:
      return "DW_OP_lit28";
    case DW_OP_lit29:
      return "DW_OP_lit29";
    case DW_OP_lit30:
      return "DW_OP_lit30";
    case DW_OP_lit31:
      return "DW_OP_lit31";
    case DW_OP_reg0:
      return "DW_OP_reg0";
    case DW_OP_reg1:
      return "DW_OP_reg1";
    case DW_OP_reg2:
      return "DW_OP_reg2";
    case DW_OP_reg3:
      return "DW_OP_reg3";
    case DW_OP_reg4:
      return "DW_OP_reg4";
    case DW_OP_reg5:
      return "DW_OP_reg5";
    case DW_OP_reg6:
      return "DW_OP_reg6";
    case DW_OP_reg7:
      return "DW_OP_reg7";
    case DW_OP_reg8:
      return "DW_OP_reg8";
    case DW_OP_reg9:
      return "DW_OP_reg9";
    case DW_OP_reg10:
      return "DW_OP_reg10";
    case DW_OP_reg11:
      return "DW_OP_reg11";
    case DW_OP_reg12:
      return "DW_OP_reg12";
    case DW_OP_reg13:
      return "DW_OP_reg13";
    case DW_OP_reg14:
      return "DW_OP_reg14";
    case DW_OP_reg15:
      return "DW_OP_reg15";
    case DW_OP_reg16:
      return "DW_OP_reg16";
    case DW_OP_reg17:
      return "DW_OP_reg17";
    case DW_OP_reg18:
      return "DW_OP_reg18";
    case DW_OP_reg19:
      return "DW_OP_reg19";
    case DW_OP_reg20:
      return "DW_OP_reg20";
    case DW_OP_reg21:
      return "DW_OP_reg21";
    case DW_OP_reg22:
      return "DW_OP_reg22";
    case DW_OP_reg23:
      return "DW_OP_reg23";
    case DW_OP_reg24:
      return "DW_OP_reg24";
    case DW_OP_reg25:
      return "DW_OP_reg25";
    case DW_OP_reg26:
      return "DW_OP_reg26";
    case DW_OP_reg27:
      return "DW_OP_reg27";
    case DW_OP_reg28:
      return "DW_OP_reg28";
    case DW_OP_reg29:
      return "DW_OP_reg29";
    case DW_OP_reg30:
      return "DW_OP_reg30";
    case DW_OP_reg31:
      return "DW_OP_reg31";
    case DW_OP_breg0:
      return "DW_OP_breg0";
    case DW_OP_breg1:
      return "DW_OP_breg1";
    case DW_OP_breg2:
      return "DW_OP_breg2";
    case DW_OP_breg3:
      return "DW_OP_breg3";
    case DW_OP_breg4:
      return "DW_OP_breg4";
    case DW_OP_breg5:
      return "DW_OP_breg5";
    case DW_OP_breg6:
      return "DW_OP_breg6";
    case DW_OP_breg7:
      return "DW_OP_breg7";
    case DW_OP_breg8:
      return "DW_OP_breg8";
    case DW_OP_breg9:
      return "DW_OP_breg9";
    case DW_OP_breg10:
      return "DW_OP_breg10";
    case DW_OP_breg11:
      return "DW_OP_breg11";
    case DW_OP_breg12:
      return "DW_OP_breg12";
    case DW_OP_breg13:
      return "DW_OP_breg13";
    case DW_OP_breg14:
      return "DW_OP_breg14";
    case DW_OP_breg15:
      return "DW_OP_breg15";
    case DW_OP_breg16:
      return "DW_OP_breg16";
    case DW_OP_breg17:
      return "DW_OP_breg17";
    case DW_OP_breg18:
      return "DW_OP_breg18";
    case DW_OP_breg19:
      return "DW_OP_breg19";
    case DW_OP_breg20:
      return "DW_OP_breg20";
    case DW_OP_breg21:
      return "DW_OP_breg21";
    case DW_OP_breg22:
      return "DW_OP_breg22";
    case DW_OP_breg23:
      return "DW_OP_breg23";
    case DW_OP_breg24:
      return "DW_OP_breg24";
    case DW_OP_breg25:
      return "DW_OP_breg25";
    case DW_OP_breg26:
      return "DW_OP_breg26";
    case DW_OP_breg27:
      return "DW_OP_breg27";
    case DW_OP_breg28:
      return "DW_OP_breg28";
    case DW_OP_breg29:
      return "DW_OP_breg29";
    case DW_OP_breg30:
      return "DW_OP_breg30";
    case DW_OP_breg31:
      return "DW_OP_breg31";
    case DW_OP_regx:
      return "DW_OP_regx";
    case DW_OP_fbreg:
      return "DW_OP_fbreg";
    case DW_OP_bregx:
      return "DW_OP_bregx";
    case DW_OP_piece:
      return "DW_OP_piece";
    case DW_OP_deref_size:
      return "DW_OP_deref_size";
    case DW_OP_xderef_size:
      return "DW_OP_xderef_size";
    case DW_OP_nop:
      return "DW_OP_nop";
    case DW_OP_push_object_address:
      return "DW_OP_push_object_address";
    case DW_OP_call2:
      return "DW_OP_call2";
    case DW_OP_call4:
      return "DW_OP_call4";
    case DW_OP_call_ref:
      return "DW_OP_call_ref";
    case DW_OP_GNU_push_tls_address:
      return "DW_OP_GNU_push_tls_address";
    default:
      return "OP_<unknown>";
    }
}

/* Return a pointer to a newly allocated location description.  Location
   descriptions are simple expression terms that can be strung
   together to form more complicated location (address) descriptions.  */

static inline dw_loc_descr_ref
new_loc_descr (enum dwarf_location_atom op, unsigned HOST_WIDE_INT oprnd1,
               unsigned HOST_WIDE_INT oprnd2)
{
  dw_loc_descr_ref descr = ggc_alloc_cleared (sizeof (dw_loc_descr_node));

  descr->dw_loc_opc = op;
  descr->dw_loc_oprnd1.val_class = dw_val_class_unsigned_const;
  descr->dw_loc_oprnd1.v.val_unsigned = oprnd1;
  descr->dw_loc_oprnd2.val_class = dw_val_class_unsigned_const;
  descr->dw_loc_oprnd2.v.val_unsigned = oprnd2;

  return descr;
}


/* Add a location description term to a location description expression.  */

static inline void
add_loc_descr (dw_loc_descr_ref *list_head, dw_loc_descr_ref descr)
{
  dw_loc_descr_ref *d;

  /* Find the end of the chain.  */
  for (d = list_head; (*d) != NULL; d = &(*d)->dw_loc_next)
    ;

  *d = descr;
}

/* Return the size of a location descriptor.  */

static unsigned long
size_of_loc_descr (dw_loc_descr_ref loc)
{
  unsigned long size = 1;

  switch (loc->dw_loc_opc)
    {
    case DW_OP_addr:
    case INTERNAL_DW_OP_tls_addr:
      size += DWARF2_ADDR_SIZE;
      break;
    case DW_OP_const1u:
    case DW_OP_const1s:
      size += 1;
      break;
    case DW_OP_const2u:
    case DW_OP_const2s:
      size += 2;
      break;
    case DW_OP_const4u:
    case DW_OP_const4s:
      size += 4;
      break;
    case DW_OP_const8u:
    case DW_OP_const8s:
      size += 8;
      break;
    case DW_OP_constu:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      break;
    case DW_OP_consts:
      size += size_of_sleb128 (loc->dw_loc_oprnd1.v.val_int);
      break;
    case DW_OP_pick:
      size += 1;
      break;
    case DW_OP_plus_uconst:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      break;
    case DW_OP_skip:
    case DW_OP_bra:
      size += 2;
      break;
    case DW_OP_breg0:
    case DW_OP_breg1:
    case DW_OP_breg2:
    case DW_OP_breg3:
    case DW_OP_breg4:
    case DW_OP_breg5:
    case DW_OP_breg6:
    case DW_OP_breg7:
    case DW_OP_breg8:
    case DW_OP_breg9:
    case DW_OP_breg10:
    case DW_OP_breg11:
    case DW_OP_breg12:
    case DW_OP_breg13:
    case DW_OP_breg14:
    case DW_OP_breg15:
    case DW_OP_breg16:
    case DW_OP_breg17:
    case DW_OP_breg18:
    case DW_OP_breg19:
    case DW_OP_breg20:
    case DW_OP_breg21:
    case DW_OP_breg22:
    case DW_OP_breg23:
    case DW_OP_breg24:
    case DW_OP_breg25:
    case DW_OP_breg26:
    case DW_OP_breg27:
    case DW_OP_breg28:
    case DW_OP_breg29:
    case DW_OP_breg30:
    case DW_OP_breg31:
      size += size_of_sleb128 (loc->dw_loc_oprnd1.v.val_int);
      break;
    case DW_OP_regx:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      break;
    case DW_OP_fbreg:
      size += size_of_sleb128 (loc->dw_loc_oprnd1.v.val_int);
      break;
    case DW_OP_bregx:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      size += size_of_sleb128 (loc->dw_loc_oprnd2.v.val_int);
      break;
    case DW_OP_piece:
      size += size_of_uleb128 (loc->dw_loc_oprnd1.v.val_unsigned);
      break;
    case DW_OP_deref_size:
    case DW_OP_xderef_size:
      size += 1;
      break;
    case DW_OP_call2:
      size += 2;
      break;
    case DW_OP_call4:
      size += 4;
      break;
    case DW_OP_call_ref:
      size += DWARF2_ADDR_SIZE;
      break;
    default:
      break;
    }

  return size;
}

/* Return the size of a series of location descriptors.  */

static unsigned long
size_of_locs (dw_loc_descr_ref loc)
{
  unsigned long size;

  for (size = 0; loc != NULL; loc = loc->dw_loc_next)
    {
      loc->dw_loc_addr = size;
      size += size_of_loc_descr (loc);
    }

  return size;
}

/* Output location description stack opcode's operands (if any).  */

static void
output_loc_operands (dw_loc_descr_ref loc)
{
  dw_val_ref val1 = &loc->dw_loc_oprnd1;
  dw_val_ref val2 = &loc->dw_loc_oprnd2;

  switch (loc->dw_loc_opc)
    {
#ifdef DWARF2_DEBUGGING_INFO
    case DW_OP_addr:
      dw2_asm_output_addr_rtx (DWARF2_ADDR_SIZE, val1->v.val_addr, NULL);
      break;
    case DW_OP_const2u:
    case DW_OP_const2s:
      dw2_asm_output_data (2, val1->v.val_int, NULL);
      break;
    case DW_OP_const4u:
    case DW_OP_const4s:
      dw2_asm_output_data (4, val1->v.val_int, NULL);
      break;
    case DW_OP_const8u:
    case DW_OP_const8s:
      gcc_assert (HOST_BITS_PER_LONG >= 64);
      dw2_asm_output_data (8, val1->v.val_int, NULL);
      break;
    case DW_OP_skip:
    case DW_OP_bra:
      {
        int offset;

        gcc_assert (val1->val_class == dw_val_class_loc);
        offset = val1->v.val_loc->dw_loc_addr - (loc->dw_loc_addr + 3);

        dw2_asm_output_data (2, offset, NULL);
      }
      break;
#else
    case DW_OP_addr:
    case DW_OP_const2u:
    case DW_OP_const2s:
    case DW_OP_const4u:
    case DW_OP_const4s:
    case DW_OP_const8u:
    case DW_OP_const8s:
    case DW_OP_skip:
    case DW_OP_bra:
      /* We currently don't make any attempt to make sure these are
         aligned properly like we do for the main unwind info, so
         don't support emitting things larger than a byte if we're
         only doing unwinding.  */
      gcc_unreachable ();
#endif
    case DW_OP_const1u:
    case DW_OP_const1s:
      dw2_asm_output_data (1, val1->v.val_int, NULL);
      break;
    case DW_OP_constu:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      break;
    case DW_OP_consts:
      dw2_asm_output_data_sleb128 (val1->v.val_int, NULL);
      break;
    case DW_OP_pick:
      dw2_asm_output_data (1, val1->v.val_int, NULL);
      break;
    case DW_OP_plus_uconst:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      break;
    case DW_OP_breg0:
    case DW_OP_breg1:
    case DW_OP_breg2:
    case DW_OP_breg3:
    case DW_OP_breg4:
    case DW_OP_breg5:
    case DW_OP_breg6:
    case DW_OP_breg7:
    case DW_OP_breg8:
    case DW_OP_breg9:
    case DW_OP_breg10:
    case DW_OP_breg11:
    case DW_OP_breg12:
    case DW_OP_breg13:
    case DW_OP_breg14:
    case DW_OP_breg15:
    case DW_OP_breg16:
    case DW_OP_breg17:
    case DW_OP_breg18:
    case DW_OP_breg19:
    case DW_OP_breg20:
    case DW_OP_breg21:
    case DW_OP_breg22:
    case DW_OP_breg23:
    case DW_OP_breg24:
    case DW_OP_breg25:
    case DW_OP_breg26:
    case DW_OP_breg27:
    case DW_OP_breg28:
    case DW_OP_breg29:
    case DW_OP_breg30:
    case DW_OP_breg31:
      dw2_asm_output_data_sleb128 (val1->v.val_int, NULL);
      break;
    case DW_OP_regx:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      break;
    case DW_OP_fbreg:
      dw2_asm_output_data_sleb128 (val1->v.val_int, NULL);
      break;
    case DW_OP_bregx:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      dw2_asm_output_data_sleb128 (val2->v.val_int, NULL);
      break;
    case DW_OP_piece:
      dw2_asm_output_data_uleb128 (val1->v.val_unsigned, NULL);
      break;
    case DW_OP_deref_size:
    case DW_OP_xderef_size:
      dw2_asm_output_data (1, val1->v.val_int, NULL);
      break;

    case INTERNAL_DW_OP_tls_addr:
#ifdef ASM_OUTPUT_DWARF_DTPREL
      ASM_OUTPUT_DWARF_DTPREL (asm_out_file, DWARF2_ADDR_SIZE,
                               val1->v.val_addr);
      fputc ('\n', asm_out_file);
#else
      gcc_unreachable ();
#endif
      break;

    default:
      /* Other codes have no operands.  */
      break;
    }
}

/* Output a sequence of location operations.  */

static void
output_loc_sequence (dw_loc_descr_ref loc)
{
  for (; loc != NULL; loc = loc->dw_loc_next)
    {
      /* Output the opcode.  */
      dw2_asm_output_data (1, loc->dw_loc_opc,
                           "%s", dwarf_stack_op_name (loc->dw_loc_opc));

      /* Output the operand(s) (if any).  */
      output_loc_operands (loc);
    }
}

/* This routine will generate the correct assembly data for a location
   description based on a cfi entry with a complex address.  */

static void
output_cfa_loc (dw_cfi_ref cfi)
{
  dw_loc_descr_ref loc;
  unsigned long size;

  /* Output the size of the block.  */
  loc = cfi->dw_cfi_oprnd1.dw_cfi_loc;
  size = size_of_locs (loc);
  dw2_asm_output_data_uleb128 (size, NULL);

  /* Now output the operations themselves.  */
  output_loc_sequence (loc);
}

/* This function builds a dwarf location descriptor sequence from
   a dw_cfa_location.  */

static struct dw_loc_descr_struct *
build_cfa_loc (dw_cfa_location *cfa)
{
  struct dw_loc_descr_struct *head, *tmp;

  gcc_assert (cfa->indirect);

  if (cfa->base_offset)
    {
      if (cfa->reg <= 31)
        head = new_loc_descr (DW_OP_breg0 + cfa->reg, cfa->base_offset, 0);
      else
        head = new_loc_descr (DW_OP_bregx, cfa->reg, cfa->base_offset);
    }
  else if (cfa->reg <= 31)
    head = new_loc_descr (DW_OP_reg0 + cfa->reg, 0, 0);
  else
    head = new_loc_descr (DW_OP_regx, cfa->reg, 0);

  head->dw_loc_oprnd1.val_class = dw_val_class_const;
  tmp = new_loc_descr (DW_OP_deref, 0, 0);
  add_loc_descr (&head, tmp);
  if (cfa->offset != 0)
    {
      tmp = new_loc_descr (DW_OP_plus_uconst, cfa->offset, 0);
      add_loc_descr (&head, tmp);
    }

  return head;
}

/* This function fills in aa dw_cfa_location structure from a dwarf location
   descriptor sequence.  */

static void
get_cfa_from_loc_descr (dw_cfa_location *cfa, struct dw_loc_descr_struct *loc)
{
  struct dw_loc_descr_struct *ptr;
  cfa->offset = 0;
  cfa->base_offset = 0;
  cfa->indirect = 0;
  cfa->reg = -1;

  for (ptr = loc; ptr != NULL; ptr = ptr->dw_loc_next)
    {
      enum dwarf_location_atom op = ptr->dw_loc_opc;

      switch (op)
        {
        case DW_OP_reg0:
        case DW_OP_reg1:
        case DW_OP_reg2:
        case DW_OP_reg3:
        case DW_OP_reg4:
        case DW_OP_reg5:
        case DW_OP_reg6:
        case DW_OP_reg7:
        case DW_OP_reg8:
        case DW_OP_reg9:
        case DW_OP_reg10:
        case DW_OP_reg11:
        case DW_OP_reg12:
        case DW_OP_reg13:
        case DW_OP_reg14:
        case DW_OP_reg15:
        case DW_OP_reg16:
        case DW_OP_reg17:
        case DW_OP_reg18:
        case DW_OP_reg19:
        case DW_OP_reg20:
        case DW_OP_reg21:
        case DW_OP_reg22:
        case DW_OP_reg23:
        case DW_OP_reg24:
        case DW_OP_reg25:
        case DW_OP_reg26:
        case DW_OP_reg27:
        case DW_OP_reg28:
        case DW_OP_reg29:
        case DW_OP_reg30:
        case DW_OP_reg31:
          cfa->reg = op - DW_OP_reg0;
          break;
        case DW_OP_regx:
          cfa->reg = ptr->dw_loc_oprnd1.v.val_int;
          break;
        case DW_OP_breg0:
        case DW_OP_breg1:
        case DW_OP_breg2:
        case DW_OP_breg3:
        case DW_OP_breg4:
        case DW_OP_breg5:
        case DW_OP_breg6:
        case DW_OP_breg7:
        case DW_OP_breg8:
        case DW_OP_breg9:
        case DW_OP_breg10:
        case DW_OP_breg11:
        case DW_OP_breg12:
        case DW_OP_breg13:
        case DW_OP_breg14:
        case DW_OP_breg15:
        case DW_OP_breg16:
        case DW_OP_breg17:
        case DW_OP_breg18:
        case DW_OP_breg19:
        case DW_OP_breg20:
        case DW_OP_breg21:
        case DW_OP_breg22:
        case DW_OP_breg23:
        case DW_OP_breg24:
        case DW_OP_breg25:
        case DW_OP_breg26:
        case DW_OP_breg27:
        case DW_OP_breg28:
        case DW_OP_breg29:
        case DW_OP_breg30:
        case DW_OP_breg31:
          cfa->reg = op - DW_OP_breg0;
          cfa->base_offset = ptr->dw_loc_oprnd1.v.val_int;
          break;
        case DW_OP_bregx:
          cfa->reg = ptr->dw_loc_oprnd1.v.val_int;
          cfa->base_offset = ptr->dw_loc_oprnd2.v.val_int;
          break;
        case DW_OP_deref:
          cfa->indirect = 1;
          break;
        case DW_OP_plus_uconst:
          cfa->offset = ptr->dw_loc_oprnd1.v.val_unsigned;
          break;
        default:
          internal_error ("DW_LOC_OP %s not implemented\n",
                          dwarf_stack_op_name (ptr->dw_loc_opc));
        }
    }
}
#endif /* .debug_frame support */
\f
/* And now, the support for symbolic debugging information.  */
#ifdef DWARF2_DEBUGGING_INFO

/* .debug_str support.  */
static int output_indirect_string (void **, void *);

static void dwarf2out_init (const char *);
static void dwarf2out_finish (const char *);
static void dwarf2out_define (unsigned int, const char *);
static void dwarf2out_undef (unsigned int, const char *);
static void dwarf2out_start_source_file (unsigned, const char *);
static void dwarf2out_end_source_file (unsigned);
static void dwarf2out_begin_block (unsigned, unsigned);
static void dwarf2out_end_block (unsigned, unsigned);
static bool dwarf2out_ignore_block (tree);
static void dwarf2out_global_decl (tree);
static void dwarf2out_type_decl (tree, int);
static void dwarf2out_imported_module_or_decl (tree, tree);
static void dwarf2out_abstract_function (tree);
static void dwarf2out_var_location (rtx);
static void dwarf2out_begin_function (tree);

/* The debug hooks structure.  */

const struct gcc_debug_hooks dwarf2_debug_hooks =
{
  dwarf2out_init,
  dwarf2out_finish,
  dwarf2out_define,
  dwarf2out_undef,
  dwarf2out_start_source_file,
  dwarf2out_end_source_file,
  dwarf2out_begin_block,
  dwarf2out_end_block,
  dwarf2out_ignore_block,
  dwarf2out_source_line,
  dwarf2out_begin_prologue,
  debug_nothing_int_charstar,   /* end_prologue */
  dwarf2out_end_epilogue,
  dwarf2out_begin_function,
  debug_nothing_int,            /* end_function */
  dwarf2out_decl,               /* function_decl */
  dwarf2out_global_decl,
  dwarf2out_type_decl,          /* type_decl */
  dwarf2out_imported_module_or_decl,
  debug_nothing_tree,           /* deferred_inline_function */
  /* The DWARF 2 backend tries to reduce debugging bloat by not
     emitting the abstract description of inline functions until
     something tries to reference them.  */
  dwarf2out_abstract_function,  /* outlining_inline_function */
  debug_nothing_rtx,            /* label */
  debug_nothing_int,            /* handle_pch */
  dwarf2out_var_location,
  1                             /* start_end_main_source_file */
};
#endif
\f
/* NOTE: In the comments in this file, many references are made to
   "Debugging Information Entries".  This term is abbreviated as `DIE'
   throughout the remainder of this file.  */

/* An internal representation of the DWARF output is built, and then
   walked to generate the DWARF debugging info.  The walk of the internal
   representation is done after the entire program has been compiled.
   The types below are used to describe the internal representation.  */

/* Various DIE's use offsets relative to the beginning of the
   .debug_info section to refer to each other.  */

typedef long int dw_offset;

/* Define typedefs here to avoid circular dependencies.  */

typedef struct dw_attr_struct *dw_attr_ref;
typedef struct dw_line_info_struct *dw_line_info_ref;
typedef struct dw_separate_line_info_struct *dw_separate_line_info_ref;
typedef struct pubname_struct *pubname_ref;
typedef struct dw_ranges_struct *dw_ranges_ref;

/* Each entry in the line_info_table maintains the file and
   line number associated with the label generated for that
   entry.  The label gives the PC value associated with
   the line number entry.  */

typedef struct dw_line_info_struct GTY(())
{
  unsigned long dw_file_num;
  unsigned long dw_line_num;
}
dw_line_info_entry;

/* Line information for functions in separate sections; each one gets its
   own sequence.  */
typedef struct dw_separate_line_info_struct GTY(())
{
  unsigned long dw_file_num;
  unsigned long dw_line_num;
  unsigned long function;
}
dw_separate_line_info_entry;

/* Each DIE attribute has a field specifying the attribute kind,
   a link to the next attribute in the chain, and an attribute value.
   Attributes are typically linked below the DIE they modify.  */

typedef struct dw_attr_struct GTY(())
{
  enum dwarf_attribute dw_attr;
  dw_attr_ref dw_attr_next;
  dw_val_node dw_attr_val;
}
dw_attr_node;

/* The Debugging Information Entry (DIE) structure */

typedef struct die_struct GTY(())
{
  enum dwarf_tag die_tag;
  char *die_symbol;
  dw_attr_ref die_attr;
  dw_die_ref die_parent;
  dw_die_ref die_child;
  dw_die_ref die_sib;
  dw_die_ref die_definition; /* ref from a specification to its definition */
  dw_offset die_offset;
  unsigned long die_abbrev;
  int die_mark;
  unsigned int decl_id;
}
die_node;

/* The pubname structure */

typedef struct pubname_struct GTY(())
{
  dw_die_ref die;
  char *name;
}
pubname_entry;

struct dw_ranges_struct GTY(())
{
  int block_num;
};

/* The limbo die list structure.  */
typedef struct limbo_die_struct GTY(())
{
  dw_die_ref die;
  tree created_for;
  struct limbo_die_struct *next;
}
limbo_die_node;

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

/* Define a macro which returns nonzero for a TYPE_DECL which was
   implicitly generated for a tagged type.

   Note that unlike the gcc front end (which generates a NULL named
   TYPE_DECL node for each complete tagged type, each array type, and
   each function type node created) the g++ front end generates a
   _named_ TYPE_DECL node for each tagged type node created.
   These TYPE_DECLs have DECL_ARTIFICIAL set, so we know not to
   generate a DW_TAG_typedef DIE for them.  */

#define TYPE_DECL_IS_STUB(decl)                         \
  (DECL_NAME (decl) == NULL_TREE                        \
   || (DECL_ARTIFICIAL (decl)                           \
       && is_tagged_type (TREE_TYPE (decl))             \
       && ((decl == TYPE_STUB_DECL (TREE_TYPE (decl)))  \
           /* This is necessary for stub decls that     \
              appear in nested inline functions.  */    \
           || (DECL_ABSTRACT_ORIGIN (decl) != NULL_TREE \
               && (decl_ultimate_origin (decl)          \
                   == TYPE_STUB_DECL (TREE_TYPE (decl)))))))

/* Information concerning the compilation unit's programming
   language, and compiler version.  */

/* Fixed size portion of the DWARF compilation unit header.  */
#define DWARF_COMPILE_UNIT_HEADER_SIZE \
  (DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE + 3)

/* Fixed size portion of public names info.  */
#define DWARF_PUBNAMES_HEADER_SIZE (2 * DWARF_OFFSET_SIZE + 2)

/* Fixed size portion of the address range info.  */
#define DWARF_ARANGES_HEADER_SIZE                                       \
  (DWARF_ROUND (DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE + 4,      \
                DWARF2_ADDR_SIZE * 2)                                   \
   - DWARF_INITIAL_LENGTH_SIZE)

/* Size of padding portion in the address range info.  It must be
   aligned to twice the pointer size.  */
#define DWARF_ARANGES_PAD_SIZE \
  (DWARF_ROUND (DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE + 4, \
                DWARF2_ADDR_SIZE * 2) \
   - (DWARF_INITIAL_LENGTH_SIZE + DWARF_OFFSET_SIZE + 4))

/* Use assembler line directives if available.  */
#ifndef DWARF2_ASM_LINE_DEBUG_INFO
#ifdef HAVE_AS_DWARF2_DEBUG_LINE
#define DWARF2_ASM_LINE_DEBUG_INFO 1
#else
#define DWARF2_ASM_LINE_DEBUG_INFO 0
#endif
#endif

/* Minimum line offset in a special line info. opcode.
   This value was chosen to give a reasonable range of values.  */
#define DWARF_LINE_BASE  -10

/* First special line opcode - leave room for the standard opcodes.  */
#define DWARF_LINE_OPCODE_BASE  10

/* Range of line offsets in a special line info. opcode.  */
#define DWARF_LINE_RANGE  (254-DWARF_LINE_OPCODE_BASE+1)

/* 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 DWARF_LINE_DEFAULT_IS_STMT_START 1

#ifdef DWARF2_DEBUGGING_INFO
/* This location is used by calc_die_sizes() to keep track
   the offset of each DIE within the .debug_info section.  */
static unsigned long next_die_offset;
#endif

/* Record the root of the DIE's built for the current compilation unit.  */
static GTY(()) dw_die_ref comp_unit_die;