Subversion Repositories openrisc

/* GAS interface for targets using CGEN: Cpu tools GENerator.

   Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,

   2006, 2007, 2009 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3, or (at your option)

   any later version.

   GAS 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 GAS; see the file COPYING.  If not, write to the Free Software

   Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */

#include <setjmp.h>

#include "as.h"

#include "symcat.h"

#include "cgen-desc.h"

#include "subsegs.h"

#include "cgen.h"

#include "dwarf2dbg.h"

#include "symbols.h"

#include "struc-symbol.h"

#ifdef OBJ_COMPLEX_RELC

static expressionS * make_right_shifted_expr

  (expressionS *, const int, const int);

static unsigned long gas_cgen_encode_addend

  (const unsigned long, const unsigned long, const unsigned long, \

   const unsigned long, const unsigned long, const unsigned long, \

   const unsigned long);

static char * weak_operand_overflow_check

  (const expressionS *, const CGEN_OPERAND *);

static void queue_fixup_recursively

  (const int, const int, expressionS *, \

   const CGEN_MAYBE_MULTI_IFLD *, const int, const int);

static int rightshift = 0;

#endif

static void queue_fixup (int, int, expressionS *);

/* Opcode table descriptor, must be set by md_begin.  */

CGEN_CPU_DESC gas_cgen_cpu_desc;

/* Callback to insert a register into the symbol table.

   A target may choose to let GAS parse the registers.

   ??? Not currently used.  */

void

cgen_asm_record_register (name, number)

     char *name;

     int number;

{

  /* Use symbol_create here instead of symbol_new so we don't try to

     output registers into the object file's symbol table.  */

  symbol_table_insert (symbol_create (name, reg_section,

                                      number, &zero_address_frag));

}

/* We need to keep a list of fixups.  We can't simply generate them as

   we go, because that would require us to first create the frag, and

   that would screw up references to ``.''.

   This is used by cpu's with simple operands.  It keeps knowledge of what

   an `expressionS' is and what a `fixup' is out of CGEN which for the time

   being is preferable.

   OPINDEX is the index in the operand table.

   OPINFO is something the caller chooses to help in reloc determination.  */

struct fixup

{

  int opindex;

  int opinfo;

  expressionS exp;

  struct cgen_maybe_multi_ifield * field;

  int msb_field_p;

};

static struct fixup fixups[GAS_CGEN_MAX_FIXUPS];

static int num_fixups;

/* Prepare to parse an instruction.

   ??? May wish to make this static and delete calls in md_assemble.  */

void

gas_cgen_init_parse ()

{

  num_fixups = 0;

}

/* Queue a fixup.  */

static void

queue_fixup (opindex, opinfo, expP)

     int           opindex;

     int           opinfo;

     expressionS * expP;

{

  /* We need to generate a fixup for this expression.  */

  if (num_fixups >= GAS_CGEN_MAX_FIXUPS)

    as_fatal (_("too many fixups"));

  fixups[num_fixups].exp     = *expP;

  fixups[num_fixups].opindex = opindex;

  fixups[num_fixups].opinfo  = opinfo;

  ++ num_fixups;

}

/* The following functions allow fixup chains to be stored, retrieved,

   and swapped.  They are a generalization of a pre-existing scheme

   for storing, restoring and swapping fixup chains that was used by

   the m32r port.  The functionality is essentially the same, only

   instead of only being able to store a single fixup chain, an entire

   array of fixup chains can be stored.  It is the user's responsibility

   to keep track of how many fixup chains have been stored and which

   elements of the array they are in.

   The algorithms used are the same as in the old scheme.  Other than the

   "array-ness" of the whole thing, the functionality is identical to the

   old scheme.

   gas_cgen_initialize_saved_fixups_array():

      Sets num_fixups_in_chain to 0 for each element. Call this from

      md_begin() if you plan to use these functions and you want the

      fixup count in each element to be set to 0 initially.  This is

      not necessary, but it's included just in case.  It performs

      the same function for each element in the array of fixup chains

      that gas_init_parse() performs for the current fixups.

   gas_cgen_save_fixups (element):

      element - element number of the array you wish to store the fixups

                to.  No mechanism is built in for tracking what element

                was last stored to.

   gas_cgen_restore_fixups (element):

      element - element number of the array you wish to restore the fixups

                from.

   gas_cgen_swap_fixups(int element):

       element - swap the current fixups with those in this element number.

*/

struct saved_fixups

{

  struct fixup fixup_chain[GAS_CGEN_MAX_FIXUPS];

  int num_fixups_in_chain;

};

static struct saved_fixups stored_fixups[MAX_SAVED_FIXUP_CHAINS];

void

gas_cgen_initialize_saved_fixups_array ()

{

  int i = 0;

  while (i < MAX_SAVED_FIXUP_CHAINS)

    stored_fixups[i++].num_fixups_in_chain = 0;

}

void

gas_cgen_save_fixups (i)

     int i;

{

  if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)

    {

      as_fatal ("index into stored_fixups[] out of bounds");

      return;

    }

  stored_fixups[i].num_fixups_in_chain = num_fixups;

  memcpy (stored_fixups[i].fixup_chain, fixups,

          sizeof (fixups[0]) * num_fixups);

  num_fixups = 0;

}

void

gas_cgen_restore_fixups (i)

     int i;

{

  if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)

    {

      as_fatal ("index into stored_fixups[] out of bounds");

      return;

    }

  num_fixups = stored_fixups[i].num_fixups_in_chain;

  memcpy (fixups, stored_fixups[i].fixup_chain,

          (sizeof (stored_fixups[i].fixup_chain[0])) * num_fixups);

  stored_fixups[i].num_fixups_in_chain = 0;

}

void

gas_cgen_swap_fixups (i)

     int i;

{

  if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)

    {

      as_fatal ("index into stored_fixups[] out of bounds");

      return;

    }

  if (num_fixups == 0)

    gas_cgen_restore_fixups (i);

  else if (stored_fixups[i].num_fixups_in_chain == 0)

    gas_cgen_save_fixups (i);

  else

    {

      int tmp;

      struct fixup tmp_fixup;

      tmp = stored_fixups[i].num_fixups_in_chain;

      stored_fixups[i].num_fixups_in_chain = num_fixups;

      num_fixups = tmp;

      for (tmp = GAS_CGEN_MAX_FIXUPS; tmp--;)

        {

          tmp_fixup = stored_fixups[i].fixup_chain [tmp];

          stored_fixups[i].fixup_chain[tmp] = fixups [tmp];

          fixups [tmp] = tmp_fixup;

        }

    }

}

/* Default routine to record a fixup.

   This is a cover function to fix_new.

   It exists because we record INSN with the fixup.

   FRAG and WHERE are their respective arguments to fix_new_exp.

   LENGTH is in bits.

   OPINFO is something the caller chooses to help in reloc determination.

   At this point we do not use a bfd_reloc_code_real_type for

   operands residing in the insn, but instead just use the

   operand index.  This lets us easily handle fixups for any

   operand type.  We pick a BFD reloc type in md_apply_fix.  */

fixS *

gas_cgen_record_fixup (frag, where, insn, length, operand, opinfo, symbol, offset)

     fragS *              frag;

     int                  where;

     const CGEN_INSN *    insn;

     int                  length;

     const CGEN_OPERAND * operand;

     int                  opinfo;

     symbolS *            symbol;

     offsetT              offset;

{

  fixS *fixP;

  /* It may seem strange to use operand->attrs and not insn->attrs here,

     but it is the operand that has a pc relative relocation.  */

  fixP = fix_new (frag, where, length / 8, symbol, offset,

                  CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR),

                  (bfd_reloc_code_real_type)

                    ((int) BFD_RELOC_UNUSED

                     + (int) operand->type));

  fixP->fx_cgen.insn = insn;

  fixP->fx_cgen.opinfo = opinfo;

  fixP->fx_cgen.field = NULL;

  fixP->fx_cgen.msb_field_p = 0;

  return fixP;

}

/* Default routine to record a fixup given an expression.

   This is a cover function to fix_new_exp.

   It exists because we record INSN with the fixup.

   FRAG and WHERE are their respective arguments to fix_new_exp.

   LENGTH is in bits.

   OPINFO is something the caller chooses to help in reloc determination.

   At this point we do not use a bfd_reloc_code_real_type for

   operands residing in the insn, but instead just use the

   operand index.  This lets us easily handle fixups for any

   operand type.  We pick a BFD reloc type in md_apply_fix.  */

fixS *

gas_cgen_record_fixup_exp (frag, where, insn, length, operand, opinfo, exp)

     fragS *              frag;

     int                  where;

     const CGEN_INSN *    insn;

     int                  length;

     const CGEN_OPERAND * operand;

     int                  opinfo;

     expressionS *        exp;

{

  fixS *fixP;

  /* It may seem strange to use operand->attrs and not insn->attrs here,

     but it is the operand that has a pc relative relocation.  */

  fixP = fix_new_exp (frag, where, length / 8, exp,

                      CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR),

                      (bfd_reloc_code_real_type)

                        ((int) BFD_RELOC_UNUSED

                         + (int) operand->type));

  fixP->fx_cgen.insn = insn;

  fixP->fx_cgen.opinfo = opinfo;

  fixP->fx_cgen.field = NULL;

  fixP->fx_cgen.msb_field_p = 0;

  return fixP;

}

#ifdef OBJ_COMPLEX_RELC

static symbolS *

expr_build_binary (operatorT op, symbolS * s1, symbolS * s2)

{

  expressionS e;

  e.X_op = op;

  e.X_add_symbol = s1;

  e.X_op_symbol = s2;

  e.X_add_number = 0;

  return make_expr_symbol (& e);

}

#endif

/* Used for communication between the next two procedures.  */

static jmp_buf expr_jmp_buf;

static int expr_jmp_buf_p;

/* Callback for cgen interface.  Parse the expression at *STRP.

   The result is an error message or NULL for success (in which case

   *STRP is advanced past the parsed text).

   WANT is an indication of what the caller is looking for.

   If WANT == CGEN_ASM_PARSE_INIT the caller is beginning to try to match

   a table entry with the insn, reset the queued fixups counter.

   An enum cgen_parse_operand_result is stored in RESULTP.

   OPINDEX is the operand's table entry index.

   OPINFO is something the caller chooses to help in reloc determination.

   The resulting value is stored in VALUEP.  */

const char *

gas_cgen_parse_operand (cd, want, strP, opindex, opinfo, resultP, valueP)

#ifdef OBJ_COMPLEX_RELC

     CGEN_CPU_DESC cd;

#else

     CGEN_CPU_DESC cd ATTRIBUTE_UNUSED;

#endif

     enum cgen_parse_operand_type want;

     const char **strP;

     int opindex;

     int opinfo;

     enum cgen_parse_operand_result *resultP;

     bfd_vma *valueP;

{

#ifdef __STDC__

  /* These are volatile to survive the setjmp.  */

  char * volatile hold;

  enum cgen_parse_operand_result * volatile resultP_1;

  volatile int opinfo_1;

#else

  static char *hold;

  static enum cgen_parse_operand_result *resultP_1;

  int opinfo_1;

#endif

  const char *errmsg;

  expressionS exp;

#ifdef OBJ_COMPLEX_RELC

  volatile int              signed_p = 0;

  symbolS *                 stmp = NULL;

  bfd_reloc_code_real_type  reloc_type;

  const CGEN_OPERAND *      operand;

  fixS                      dummy_fixup;

#endif

  if (want == CGEN_PARSE_OPERAND_INIT)

    {

      gas_cgen_init_parse ();

      return NULL;

    }

  resultP_1 = resultP;

  hold = input_line_pointer;

  input_line_pointer = (char *) *strP;

  opinfo_1 = opinfo;

  /* We rely on md_operand to longjmp back to us.

     This is done via gas_cgen_md_operand.  */

  if (setjmp (expr_jmp_buf) != 0)

    {

      expr_jmp_buf_p = 0;

      input_line_pointer = (char *) hold;

      *resultP_1 = CGEN_PARSE_OPERAND_RESULT_ERROR;

      return _("illegal operand");

    }

  expr_jmp_buf_p = 1;

  expression (&exp);

  expr_jmp_buf_p = 0;

  errmsg = NULL;

  *strP = input_line_pointer;

  input_line_pointer = hold;

#ifdef TC_CGEN_PARSE_FIX_EXP

  opinfo_1 = TC_CGEN_PARSE_FIX_EXP (opinfo_1, & exp);

#endif 

  /* FIXME: Need to check `want'.  */

  switch (exp.X_op)

    {

    case O_illegal:

      errmsg = _("illegal operand");

      *resultP = CGEN_PARSE_OPERAND_RESULT_ERROR;

      break;

    case O_absent:

      errmsg = _("missing operand");

      *resultP = CGEN_PARSE_OPERAND_RESULT_ERROR;

      break;

    case O_constant:

      if (want == CGEN_PARSE_OPERAND_SYMBOLIC)

        goto de_fault;

      *valueP = exp.X_add_number;

      *resultP = CGEN_PARSE_OPERAND_RESULT_NUMBER;

      break;

    case O_register:

      *valueP = exp.X_add_number;

      *resultP = CGEN_PARSE_OPERAND_RESULT_REGISTER;

      break;

    de_fault:

    default:

#ifdef OBJ_COMPLEX_RELC

      /* Look up operand, check to see if there's an obvious

         overflow (this helps disambiguate some insn parses).  */

      operand = cgen_operand_lookup_by_num (cd, opindex);

      errmsg = weak_operand_overflow_check (& exp, operand);

      if (! errmsg)

        {

          /* Fragment the expression as necessary, and queue a reloc.  */

          memset (& dummy_fixup, 0, sizeof (fixS));

          reloc_type = md_cgen_lookup_reloc (0, operand, & dummy_fixup);

          if (exp.X_op == O_symbol

              && reloc_type == BFD_RELOC_RELC

              && exp.X_add_symbol->sy_value.X_op == O_constant

              && (!exp.X_add_symbol->bsym

                  || (exp.X_add_symbol->bsym->section != expr_section

                      && exp.X_add_symbol->bsym->section != absolute_section

                      && exp.X_add_symbol->bsym->section != undefined_section)))

            {

              /* Local labels will have been (eagerly) turned into constants

                 by now, due to the inappropriately deep insight of the

                 expression parser.  Unfortunately make_expr_symbol

                 prematurely dives into the symbol evaluator, and in this

                 case it gets a bad answer, so we manually create the

                 expression symbol we want here.  */

              stmp = symbol_create (FAKE_LABEL_NAME, expr_section, 0,

                                    & zero_address_frag);

              symbol_set_value_expression (stmp, & exp);

            }

          else

            stmp = make_expr_symbol (& exp);

          /* If this is a pc-relative RELC operand, we

             need to subtract "." from the expression.  */

          if (reloc_type == BFD_RELOC_RELC

              && CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR))

            stmp = expr_build_binary (O_subtract, stmp, expr_build_dot ());

          /* FIXME: this is not a perfect heuristic for figuring out

             whether an operand is signed: it only works when the operand

             is an immediate. it's not terribly likely that any other

             values will be signed relocs, but it's possible. */

          if (operand && (operand->hw_type == HW_H_SINT))

            signed_p = 1;

          if (stmp->bsym && (stmp->bsym->section == expr_section))

            {

              if (signed_p)

                stmp->bsym->flags |= BSF_SRELC;

              else

                stmp->bsym->flags |= BSF_RELC;

            }

          /* Now package it all up for the fixup emitter.  */

          exp.X_op = O_symbol;

          exp.X_op_symbol = 0;

          exp.X_add_symbol = stmp;

          exp.X_add_number = 0;

          /* Re-init rightshift quantity, just in case.  */

          rightshift = operand->length;

          queue_fixup_recursively (opindex, opinfo_1, & exp,

                                   (reloc_type == BFD_RELOC_RELC) ?

                                   & (operand->index_fields) : 0,

                                   signed_p, -1);

        }

      * resultP = errmsg

        ? CGEN_PARSE_OPERAND_RESULT_ERROR

        : CGEN_PARSE_OPERAND_RESULT_QUEUED;

      *valueP = 0;

#else

      queue_fixup (opindex, opinfo_1, &exp);

      *valueP = 0;

      *resultP = CGEN_PARSE_OPERAND_RESULT_QUEUED;

#endif      

      break;

    }

  return errmsg;

}

/* md_operand handler to catch unrecognized expressions and halt the

   parsing process so the next entry can be tried.

   ??? This could be done differently by adding code to `expression'.  */

void

gas_cgen_md_operand (expressionP)

     expressionS *expressionP ATTRIBUTE_UNUSED;

{

  /* Don't longjmp if we're not called from within cgen_parse_operand().  */

  if (expr_jmp_buf_p)

    longjmp (expr_jmp_buf, 1);

}

/* Finish assembling instruction INSN.

   BUF contains what we've built up so far.

   LENGTH is the size of the insn in bits.

   RELAX_P is non-zero if relaxable insns should be emitted as such.

   Otherwise they're emitted in non-relaxable forms.

   The "result" is stored in RESULT if non-NULL.  */

void

gas_cgen_finish_insn (insn, buf, length, relax_p, result)

     const CGEN_INSN *insn;

     CGEN_INSN_BYTES_PTR buf;

     unsigned int length;

     int relax_p;

     finished_insnS *result;

{

  int i;

  int relax_operand;

  char *f;

  unsigned int byte_len = length / 8;

  /* ??? Target foo issues various warnings here, so one might want to provide

     a hook here.  However, our caller is defined in tc-foo.c so there

     shouldn't be a need for a hook.  */

  /* Write out the instruction.

     It is important to fetch enough space in one call to `frag_more'.

     We use (f - frag_now->fr_literal) to compute where we are and we

     don't want frag_now to change between calls.

     Relaxable instructions: We need to ensure we allocate enough

     space for the largest insn.  */

  if (CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXED))

    /* These currently shouldn't get here.  */

    abort ();

  /* Is there a relaxable insn with the relaxable operand needing a fixup?  */

  relax_operand = -1;

  if (relax_p && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXABLE))

    {

      /* Scan the fixups for the operand affected by relaxing

         (i.e. the branch address).  */

      for (i = 0; i < num_fixups; ++i)

        {

          if (CGEN_OPERAND_ATTR_VALUE (cgen_operand_lookup_by_num (gas_cgen_cpu_desc, fixups[i].opindex),

                                       CGEN_OPERAND_RELAX))

            {

              relax_operand = i;

              break;

            }

        }

    }

  if (relax_operand != -1)

    {

      int max_len;

      fragS *old_frag;

      expressionS *exp;

      symbolS *sym;

      offsetT off;

#ifdef TC_CGEN_MAX_RELAX

      max_len = TC_CGEN_MAX_RELAX (insn, byte_len);

#else

      max_len = CGEN_MAX_INSN_SIZE;

#endif

      /* Ensure variable part and fixed part are in same fragment.  */

      /* FIXME: Having to do this seems like a hack.  */

      frag_grow (max_len);

      /* Allocate space for the fixed part.  */

      f = frag_more (byte_len);

      /* Create a relaxable fragment for this instruction.  */

      old_frag = frag_now;

      exp = &fixups[relax_operand].exp;

      sym = exp->X_add_symbol;

      off = exp->X_add_number;

      if (exp->X_op != O_constant && exp->X_op != O_symbol)

        {

          /* Handle complex expressions.  */

          sym = make_expr_symbol (exp);

          off = 0;

        }

      frag_var (rs_machine_dependent,

                max_len - byte_len /* max chars */,

                /* FIXME: When we machine generate the relax table,

                   machine generate a macro to compute subtype.  */

                1 /* subtype */,

                sym,

                off,

                f);

      /* Record the operand number with the fragment so md_convert_frag

         can use gas_cgen_md_record_fixup to record the appropriate reloc.  */

      old_frag->fr_cgen.insn    = insn;

      old_frag->fr_cgen.opindex = fixups[relax_operand].opindex;

      old_frag->fr_cgen.opinfo  = fixups[relax_operand].opinfo;

      if (result)

        result->frag = old_frag;

    }

  else

    {

      f = frag_more (byte_len);

      if (result)

        result->frag = frag_now;

    }

  /* If we're recording insns as numbers (rather than a string of bytes),

     target byte order handling is deferred until now.  */

#if CGEN_INT_INSN_P

  cgen_put_insn_value (gas_cgen_cpu_desc, (unsigned char *) f, length, *buf);

#else

  memcpy (f, buf, byte_len);

#endif

  /* Emit DWARF2 debugging information.  */

  dwarf2_emit_insn (byte_len);

  /* Create any fixups.  */

  for (i = 0; i < num_fixups; ++i)

    {

      fixS *fixP;

      const CGEN_OPERAND *operand =

        cgen_operand_lookup_by_num (gas_cgen_cpu_desc, fixups[i].opindex);

      /* Don't create fixups for these.  That's done during relaxation.

         We don't need to test for CGEN_INSN_RELAXED as they can't get here

         (see above).  */

      if (relax_p

          && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXABLE)

          && CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_RELAX))

        continue;

#ifndef md_cgen_record_fixup_exp

#define md_cgen_record_fixup_exp gas_cgen_record_fixup_exp

#endif

      fixP = md_cgen_record_fixup_exp (frag_now, f - frag_now->fr_literal,

                                       insn, length, operand,

                                       fixups[i].opinfo,

                                       &fixups[i].exp);

      fixP->fx_cgen.field = fixups[i].field;

      fixP->fx_cgen.msb_field_p = fixups[i].msb_field_p;

      if (result)

        result->fixups[i] = fixP;

    }

  if (result)

    {

      result->num_fixups = num_fixups;

      result->addr = f;

    }

}

#ifdef OBJ_COMPLEX_RELC

/* Queue many fixups, recursively. If the field is a multi-ifield,

   repeatedly queue its sub-parts, right shifted to fit into the field (we

   assume here multi-fields represent a left-to-right, MSB0-LSB0

   reading). */

static void

queue_fixup_recursively (const int                      opindex,

                         const int                      opinfo,

                         expressionS *                  expP,

                         const CGEN_MAYBE_MULTI_IFLD *  field,

                         const int                      signed_p,

                         const int                      part_of_multi)

{

  if (field && field->count)

    {

      int i;

      for (i = 0; i < field->count; ++ i)

        queue_fixup_recursively (opindex, opinfo, expP,

                                 & (field->val.multi[i]), signed_p, i);

    }

  else

    {

      expressionS * new_exp = expP;

#ifdef DEBUG

      printf ("queueing fixup for field %s\n",

              (field ? field->val.leaf->name : "??"));

      print_symbol_value (expP->X_add_symbol);

#endif

      if (field && part_of_multi != -1)