m32r.c

gcc编译工具没有什么特别

/* Subroutines used for code generation on the Mitsubishi M32R cpu.
   Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "tree.h"
#include "rtl.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "real.h"
#include "insn-config.h"
#include "conditions.h"
#include "insn-flags.h"
#include "output.h"
#include "insn-attr.h"
#include "flags.h"
#include "expr.h"
#include "recog.h"

/* Save the operands last given to a compare for use when we
   generate a scc or bcc insn.  */
rtx m32r_compare_op0, m32r_compare_op1;

/* Array of valid operand punctuation characters.  */
char m32r_punct_chars[256];

/* Selected code model.  */
char *m32r_model_string = M32R_MODEL_DEFAULT;
enum m32r_model m32r_model;

/* Selected SDA support.  */
char *m32r_sdata_string = M32R_SDATA_DEFAULT;
enum m32r_sdata m32r_sdata;


/* Forward declaration.  */
static void init_reg_tables	PROTO((void));

/* Called by OVERRIDE_OPTIONS to initialize various things.  */

void
m32r_init ()
{
  init_reg_tables ();

  /* Initialize array for PRINT_OPERAND_PUNCT_VALID_P.  */
  memset (m32r_punct_chars, 0, sizeof (m32r_punct_chars));
  m32r_punct_chars['#'] = 1;
  m32r_punct_chars['@'] = 1; /* ??? no longer used */

  /* Provide default value if not specified.  */
  if (!g_switch_set)
    g_switch_value = SDATA_DEFAULT_SIZE;

  if (strcmp (m32r_model_string, "small") == 0)
    m32r_model = M32R_MODEL_SMALL;
  else if (strcmp (m32r_model_string, "medium") == 0)
    m32r_model = M32R_MODEL_MEDIUM;
  else if (strcmp (m32r_model_string, "large") == 0)
    m32r_model = M32R_MODEL_LARGE;
  else
    error ("bad value (%s) for -mmodel switch", m32r_model_string);

  if (strcmp (m32r_sdata_string, "none") == 0)
    m32r_sdata = M32R_SDATA_NONE;
  else if (strcmp (m32r_sdata_string, "sdata") == 0)
    m32r_sdata = M32R_SDATA_SDATA;
  else if (strcmp (m32r_sdata_string, "use") == 0)
    m32r_sdata = M32R_SDATA_USE;
  else
    error ("bad value (%s) for -msdata switch", m32r_sdata_string);

}

/* Vectors to keep interesting information about registers where it can easily
   be got.  We use to use the actual mode value as the bit number, but there
   is (or may be) more than 32 modes now.  Instead we use two tables: one
   indexed by hard register number, and one indexed by mode.  */

/* The purpose of m32r_mode_class is to shrink the range of modes so that
   they all fit (as bit numbers) in a 32 bit word (again).  Each real mode is
   mapped into one m32r_mode_class mode.  */

enum m32r_mode_class
{
  C_MODE,
  S_MODE, D_MODE, T_MODE, O_MODE,
  SF_MODE, DF_MODE, TF_MODE, OF_MODE
};

/* Modes for condition codes.  */
#define C_MODES (1 << (int) C_MODE)

/* Modes for single-word and smaller quantities.  */
#define S_MODES ((1 << (int) S_MODE) | (1 << (int) SF_MODE))

/* Modes for double-word and smaller quantities.  */
#define D_MODES (S_MODES | (1 << (int) D_MODE) | (1 << DF_MODE))

/* Modes for quad-word and smaller quantities.  */
#define T_MODES (D_MODES | (1 << (int) T_MODE) | (1 << (int) TF_MODE))


/* Value is 1 if register/mode pair is acceptable on arc.  */

unsigned int m32r_hard_regno_mode_ok[FIRST_PSEUDO_REGISTER] =
{
  T_MODES, T_MODES, T_MODES, T_MODES, T_MODES, T_MODES, T_MODES, T_MODES,
  T_MODES, T_MODES, T_MODES, T_MODES, T_MODES, S_MODES, S_MODES, S_MODES,
  S_MODES, C_MODES
};

unsigned int m32r_mode_class [NUM_MACHINE_MODES];

enum reg_class m32r_regno_reg_class[FIRST_PSEUDO_REGISTER];

static void
init_reg_tables ()
{
  int i;

  for (i = 0; i < NUM_MACHINE_MODES; i++)
    {
      switch (GET_MODE_CLASS (i))
	{
	case MODE_INT:
	case MODE_PARTIAL_INT:
	case MODE_COMPLEX_INT:
	  if (GET_MODE_SIZE (i) <= 4)
	    m32r_mode_class[i] = 1 << (int) S_MODE;
	  else if (GET_MODE_SIZE (i) == 8)
	    m32r_mode_class[i] = 1 << (int) D_MODE;
	  else if (GET_MODE_SIZE (i) == 16)
	    m32r_mode_class[i] = 1 << (int) T_MODE;
	  else if (GET_MODE_SIZE (i) == 32)
	    m32r_mode_class[i] = 1 << (int) O_MODE;
	  else 
	    m32r_mode_class[i] = 0;
	  break;
	case MODE_FLOAT:
	case MODE_COMPLEX_FLOAT:
	  if (GET_MODE_SIZE (i) <= 4)
	    m32r_mode_class[i] = 1 << (int) SF_MODE;
	  else if (GET_MODE_SIZE (i) == 8)
	    m32r_mode_class[i] = 1 << (int) DF_MODE;
	  else if (GET_MODE_SIZE (i) == 16)
	    m32r_mode_class[i] = 1 << (int) TF_MODE;
	  else if (GET_MODE_SIZE (i) == 32)
	    m32r_mode_class[i] = 1 << (int) OF_MODE;
	  else 
	    m32r_mode_class[i] = 0;
	  break;
	case MODE_CC:
	default:
	  /* mode_class hasn't been initialized yet for EXTRA_CC_MODES, so
	     we must explicitly check for them here.  */
	  if (i == (int) CCmode)
	    m32r_mode_class[i] = 1 << (int) C_MODE;
	  else
	    m32r_mode_class[i] = 0;
	  break;
	}
    }

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    {
      if (GPR_P (i))
	m32r_regno_reg_class[i] = GENERAL_REGS;
      else if (i == ARG_POINTER_REGNUM)
	m32r_regno_reg_class[i] = GENERAL_REGS;
      else
	m32r_regno_reg_class[i] = NO_REGS;
    }
}

/* M32R specific attribute support.

   interrupt - for interrupt functions

   model - select code model used to access object

	small: addresses use 24 bits, use bl to make calls
	medium: addresses use 32 bits, use bl to make calls
	large: addresses use 32 bits, use seth/add3/jl to make calls

	Grep for MODEL in m32r.h for more info.
*/

static tree interrupt_ident1;
static tree interrupt_ident2;
static tree model_ident1;
static tree model_ident2;
static tree small_ident1;
static tree small_ident2;
static tree medium_ident1;
static tree medium_ident2;
static tree large_ident1;
static tree large_ident2;

static void
init_idents PROTO ((void))
{
  if (interrupt_ident1 == 0)
    {
      interrupt_ident1 = get_identifier ("interrupt");
      interrupt_ident2 = get_identifier ("__interrupt__");
      model_ident1 = get_identifier ("model");
      model_ident2 = get_identifier ("__model__");
      small_ident1 = get_identifier ("small");
      small_ident2 = get_identifier ("__small__");
      medium_ident1 = get_identifier ("medium");
      medium_ident2 = get_identifier ("__medium__");
      large_ident1 = get_identifier ("large");
      large_ident2 = get_identifier ("__large__");
    }
}

/* Return nonzero if IDENTIFIER is a valid decl attribute.  */

int
m32r_valid_machine_decl_attribute (type, attributes, identifier, args)
     tree type;
     tree attributes;
     tree identifier;
     tree args;
{
  init_idents ();

  if ((identifier == interrupt_ident1
       || identifier == interrupt_ident2)
      && list_length (args) == 0)
    return 1;

  if ((identifier == model_ident1
       || identifier == model_ident2)
      && list_length (args) == 1
      && (TREE_VALUE (args) == small_ident1
	  || TREE_VALUE (args) == small_ident2
	  || TREE_VALUE (args) == medium_ident1
	  || TREE_VALUE (args) == medium_ident2
	  || TREE_VALUE (args) == large_ident1
	  || TREE_VALUE (args) == large_ident2))
    return 1;

  return 0;
}

/* Return zero if TYPE1 and TYPE are incompatible, one if they are compatible,
   and two if they are nearly compatible (which causes a warning to be
   generated).  */

int
m32r_comp_type_attributes (type1, type2)
     tree type1, type2;
{
  return 1;
}

/* Set the default attributes for TYPE.  */

void
m32r_set_default_type_attributes (type)
     tree type;
{
}

/* A C statement or statements to switch to the appropriate
   section for output of DECL.  DECL is either a `VAR_DECL' node
   or a constant of some sort.  RELOC indicates whether forming
   the initial value of DECL requires link-time relocations.  */

void
m32r_select_section (decl, reloc)
     tree decl;
     int reloc;
{
  if (TREE_CODE (decl) == STRING_CST)
    {
      if (! flag_writable_strings)
	const_section ();
      else
	data_section ();
    }
  else if (TREE_CODE (decl) == VAR_DECL)
    {
      if (SDATA_NAME_P (XSTR (XEXP (DECL_RTL (decl), 0), 0)))
	sdata_section ();
      else if ((flag_pic && reloc)
	       || !TREE_READONLY (decl)
	       || TREE_SIDE_EFFECTS (decl)
	       || !DECL_INITIAL (decl)
	       || (DECL_INITIAL (decl) != error_mark_node
		   && !TREE_CONSTANT (DECL_INITIAL (decl))))
	data_section ();
      else
	const_section ();
    }
  else
    const_section ();
}

/* Encode section information of DECL, which is either a VAR_DECL,
   FUNCTION_DECL, STRING_CST, CONSTRUCTOR, or ???.

   For the M32R we want to record:

   - whether the object lives in .sdata/.sbss.
     objects living in .sdata/.sbss are prefixed with SDATA_FLAG_CHAR

   - what code model should be used to access the object
     small: recorded with no flag - for space efficiency since they'll
            be the most common
     medium: prefixed with MEDIUM_FLAG_CHAR
     large: prefixed with LARGE_FLAG_CHAR
*/

void
m32r_encode_section_info (decl)
     tree decl;
{
  char prefix = 0;
  tree model = 0;

  switch (TREE_CODE (decl))
    {
    case VAR_DECL :
    case FUNCTION_DECL :
      model = lookup_attribute ("model", DECL_MACHINE_ATTRIBUTES (decl));
      break;
    case STRING_CST :
    case CONSTRUCTOR :
      /* ??? document all others that can appear here */
    default :
      return;
    }

  /* Only mark the object as being small data area addressable if
     it hasn't been explicitly marked with a code model.

     The user can explicitly put an object in the small data area with the
     section attribute.  If the object is in sdata/sbss and marked with a
     code model do both [put the object in .sdata and mark it as being
     addressed with a specific code model - don't mark it as being addressed
     with an SDA reloc though].  This is ok and might be useful at times.  If
     the object doesn't fit the linker will give an error.  */

  if (! model)
    {
      if (TREE_CODE_CLASS (TREE_CODE (decl)) == 'd'
	  && DECL_SECTION_NAME (decl) != NULL_TREE)
	{
	  char *name = TREE_STRING_POINTER (DECL_SECTION_NAME (decl));
	  if (! strcmp (name, ".sdata") || ! strcmp (name, ".sbss"))
	    {
#if 0 /* ??? There's no reason to disallow this, is there?  */
	      if (TREE_READONLY (decl))
		error_with_decl (decl, "const objects cannot go in .sdata/.sbss");
#endif
	      prefix = SDATA_FLAG_CHAR;
	    }
	}
      else
	{
	  if (TREE_CODE (decl) == VAR_DECL
	      && ! TREE_READONLY (decl)
	      && ! TARGET_SDATA_NONE)
	    {
	      int size = int_size_in_bytes (TREE_TYPE (decl));

	      if (size > 0 && size <= g_switch_value)
		prefix = SDATA_FLAG_CHAR;
	    }
	}
    }

  /* If data area not decided yet, check for a code model.  */
  if (prefix == 0)
    {
      if (model)
	{
	  tree id;
	  
	  init_idents ();

	  id = TREE_VALUE (TREE_VALUE (model));

	  if (id == small_ident1 || id == small_ident2)
	    ; /* don't mark the symbol specially */
	  else if (id == medium_ident1 || id == medium_ident2)
	    prefix = MEDIUM_FLAG_CHAR;
	  else if (id == large_ident1 || id == large_ident2)
	    prefix = LARGE_FLAG_CHAR;
	  else
	    abort (); /* shouldn't happen */
	}
      else
	{
	  if (TARGET_MODEL_SMALL)
	    ; /* don't mark the symbol specially */
	  else if (TARGET_MODEL_MEDIUM)
	    prefix = MEDIUM_FLAG_CHAR;
	  else if (TARGET_MODEL_LARGE)
	    prefix = LARGE_FLAG_CHAR;
	  else
	    abort (); /* shouldn't happen */
	}
    }

  if (prefix != 0)
    {
      rtx rtl = (TREE_CODE_CLASS (TREE_CODE (decl)) != 'd'
                 ? TREE_CST_RTL (decl) : DECL_RTL (decl));
      char *str = XSTR (XEXP (rtl, 0), 0);
      int len = strlen (str);
      char *newstr = savealloc (len + 2);
      strcpy (newstr + 1, str);
      *newstr = prefix;
      XSTR (XEXP (rtl, 0), 0) = newstr;
    }
}

/* Do anything needed before RTL is emitted for each function.  */

void
m32r_init_expanders ()
{
  /* ??? At one point there was code here.  The function is left in
     to make it easy to experiment.  */
}

/* Acceptable arguments to the call insn.  */

int
call_address_operand (op, int_mode)
     rtx op;
     int int_mode;
{
  return symbolic_operand (op, int_mode);

/* Constants and values in registers are not OK, because
   the m32r BL instruction can only support PC relative branching.  */ 
}

int
call_operand (op, int_mode)
     rtx op;
     int int_mode;
{
  enum machine_mode mode = (enum machine_mode)int_mode;

  if (GET_CODE (op) != MEM)
    return 0;
  op = XEXP (op, 0);
  return call_address_operand (op, mode);
}

/* Returns 1 if OP is a symbol reference.  */