alpha.c

gcc3.2.1源代码

/* Subroutines used for code generation on the DEC Alpha.
   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001 Free Software Foundation, Inc. 
   Contributed by Richard Kenner ([e-mail])

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 "rtl.h"
#include "tree.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "real.h"
#include "insn-config.h"
#include "conditions.h"
#include "output.h"
#include "insn-attr.h"
#include "flags.h"
#include "recog.h"
#include "expr.h"
#include "optabs.h"
#include "reload.h"
#include "obstack.h"
#include "except.h"
#include "function.h"
#include "toplev.h"
#include "ggc.h"
#include "integrate.h"
#include "tm_p.h"
#include "target.h"
#include "target-def.h"
#include "debug.h"

/* Specify which cpu to schedule for.  */

enum processor_type alpha_cpu;
static const char * const alpha_cpu_name[] = 
{
  "ev4", "ev5", "ev6"
};

/* Specify how accurate floating-point traps need to be.  */

enum alpha_trap_precision alpha_tp;

/* Specify the floating-point rounding mode.  */

enum alpha_fp_rounding_mode alpha_fprm;

/* Specify which things cause traps.  */

enum alpha_fp_trap_mode alpha_fptm;

/* Strings decoded into the above options.  */

const char *alpha_cpu_string;	/* -mcpu= */
const char *alpha_tune_string;	/* -mtune= */
const char *alpha_tp_string;	/* -mtrap-precision=[p|s|i] */
const char *alpha_fprm_string;	/* -mfp-rounding-mode=[n|m|c|d] */
const char *alpha_fptm_string;	/* -mfp-trap-mode=[n|u|su|sui] */
const char *alpha_mlat_string;	/* -mmemory-latency= */

/* Save information from a "cmpxx" operation until the branch or scc is
   emitted.  */

struct alpha_compare alpha_compare;

/* Non-zero if inside of a function, because the Alpha asm can't
   handle .files inside of functions.  */

static int inside_function = FALSE;

/* The number of cycles of latency we should assume on memory reads.  */

int alpha_memory_latency = 3;

/* Whether the function needs the GP.  */

static int alpha_function_needs_gp;

/* The alias set for prologue/epilogue register save/restore.  */

static int alpha_sr_alias_set;

/* The assembler name of the current function.  */

static const char *alpha_fnname;

/* The next explicit relocation sequence number.  */
int alpha_next_sequence_number = 1;

/* The literal and gpdisp sequence numbers for this insn, as printed
   by %# and %* respectively.  */
int alpha_this_literal_sequence_number;
int alpha_this_gpdisp_sequence_number;

/* Declarations of static functions.  */
static bool decl_in_text_section
  PARAMS ((tree));
static int some_small_symbolic_operand_1
  PARAMS ((rtx *, void *));
static int split_small_symbolic_operand_1
  PARAMS ((rtx *, void *));
static bool local_symbol_p
  PARAMS ((rtx));
static void alpha_set_memflags_1
  PARAMS ((rtx, int, int, int));
static rtx alpha_emit_set_const_1
  PARAMS ((rtx, enum machine_mode, HOST_WIDE_INT, int));
static void alpha_expand_unaligned_load_words
  PARAMS ((rtx *out_regs, rtx smem, HOST_WIDE_INT words, HOST_WIDE_INT ofs));
static void alpha_expand_unaligned_store_words
  PARAMS ((rtx *out_regs, rtx smem, HOST_WIDE_INT words, HOST_WIDE_INT ofs));
static void alpha_sa_mask
  PARAMS ((unsigned long *imaskP, unsigned long *fmaskP));
static int find_lo_sum
  PARAMS ((rtx *, void *));
static int alpha_does_function_need_gp
  PARAMS ((void));
static int alpha_ra_ever_killed
  PARAMS ((void));
static const char *get_trap_mode_suffix
  PARAMS ((void));
static const char *get_round_mode_suffix
  PARAMS ((void));
static rtx set_frame_related_p
  PARAMS ((void));
static const char *alpha_lookup_xfloating_lib_func
  PARAMS ((enum rtx_code));
static int alpha_compute_xfloating_mode_arg
  PARAMS ((enum rtx_code, enum alpha_fp_rounding_mode));
static void alpha_emit_xfloating_libcall
  PARAMS ((const char *, rtx, rtx[], int, rtx));
static rtx alpha_emit_xfloating_compare
  PARAMS ((enum rtx_code, rtx, rtx));
static void alpha_output_function_end_prologue
  PARAMS ((FILE *));
static int alpha_adjust_cost
  PARAMS ((rtx, rtx, rtx, int));
static int alpha_issue_rate
  PARAMS ((void));
static int alpha_variable_issue
  PARAMS ((FILE *, int, rtx, int));

#if TARGET_ABI_UNICOSMK
static void alpha_init_machine_status
  PARAMS ((struct function *p));
static void alpha_mark_machine_status
  PARAMS ((struct function *p));
static void alpha_free_machine_status
  PARAMS ((struct function *p));
#endif

static void unicosmk_output_deferred_case_vectors PARAMS ((FILE *));
static void unicosmk_gen_dsib PARAMS ((unsigned long *imaskP));
static void unicosmk_output_ssib PARAMS ((FILE *, const char *));
static int unicosmk_need_dex PARAMS ((rtx));

/* Get the number of args of a function in one of two ways.  */
#if TARGET_ABI_OPEN_VMS || TARGET_ABI_UNICOSMK
#define NUM_ARGS current_function_args_info.num_args
#else
#define NUM_ARGS current_function_args_info
#endif

#define REG_PV 27
#define REG_RA 26

/* Initialize the GCC target structure.  */
#if TARGET_ABI_OPEN_VMS
const struct attribute_spec vms_attribute_table[];
static unsigned int vms_section_type_flags PARAMS ((tree, const char *, int));
static void vms_asm_named_section PARAMS ((const char *, unsigned int));
static void vms_asm_out_constructor PARAMS ((rtx, int));
static void vms_asm_out_destructor PARAMS ((rtx, int));
# undef TARGET_ATTRIBUTE_TABLE
# define TARGET_ATTRIBUTE_TABLE vms_attribute_table
# undef TARGET_SECTION_TYPE_FLAGS
# define TARGET_SECTION_TYPE_FLAGS vms_section_type_flags
#endif

#if TARGET_ABI_UNICOSMK
static void unicosmk_asm_named_section PARAMS ((const char *, unsigned int));
static void unicosmk_insert_attributes PARAMS ((tree, tree *));
static unsigned int unicosmk_section_type_flags PARAMS ((tree, const char *, 
							 int));
# undef TARGET_INSERT_ATTRIBUTES
# define TARGET_INSERT_ATTRIBUTES unicosmk_insert_attributes
# undef TARGET_SECTION_TYPE_FLAGS
# define TARGET_SECTION_TYPE_FLAGS unicosmk_section_type_flags
#endif

#undef TARGET_ASM_ALIGNED_HI_OP
#define TARGET_ASM_ALIGNED_HI_OP "\t.word\t"
#undef TARGET_ASM_ALIGNED_DI_OP
#define TARGET_ASM_ALIGNED_DI_OP "\t.quad\t"

/* Default unaligned ops are provided for ELF systems.  To get unaligned
   data for non-ELF systems, we have to turn off auto alignment.  */
#ifndef OBJECT_FORMAT_ELF
#undef TARGET_ASM_UNALIGNED_HI_OP
#define TARGET_ASM_UNALIGNED_HI_OP "\t.align 0\n\t.word\t"
#undef TARGET_ASM_UNALIGNED_SI_OP
#define TARGET_ASM_UNALIGNED_SI_OP "\t.align 0\n\t.long\t"
#undef TARGET_ASM_UNALIGNED_DI_OP
#define TARGET_ASM_UNALIGNED_DI_OP "\t.align 0\n\t.quad\t"
#endif

#undef TARGET_ASM_FUNCTION_END_PROLOGUE
#define TARGET_ASM_FUNCTION_END_PROLOGUE alpha_output_function_end_prologue

#undef TARGET_SCHED_ADJUST_COST
#define TARGET_SCHED_ADJUST_COST alpha_adjust_cost
#undef TARGET_SCHED_ISSUE_RATE
#define TARGET_SCHED_ISSUE_RATE alpha_issue_rate
#undef TARGET_SCHED_VARIABLE_ISSUE
#define TARGET_SCHED_VARIABLE_ISSUE alpha_variable_issue

struct gcc_target targetm = TARGET_INITIALIZER;

/* Parse target option strings.  */

void
override_options ()
{
  int i;
  static const struct cpu_table {
    const char *const name;
    const enum processor_type processor;
    const int flags;
  } cpu_table[] = {
#define EV5_MASK (MASK_CPU_EV5)
#define EV6_MASK (MASK_CPU_EV6|MASK_BWX|MASK_MAX|MASK_FIX)
    { "ev4",	PROCESSOR_EV4, 0 },
    { "ev45",	PROCESSOR_EV4, 0 },
    { "21064",	PROCESSOR_EV4, 0 },
    { "ev5",	PROCESSOR_EV5, EV5_MASK },
    { "21164",	PROCESSOR_EV5, EV5_MASK },
    { "ev56",	PROCESSOR_EV5, EV5_MASK|MASK_BWX },
    { "21164a",	PROCESSOR_EV5, EV5_MASK|MASK_BWX },
    { "pca56",	PROCESSOR_EV5, EV5_MASK|MASK_BWX|MASK_MAX },
    { "21164PC",PROCESSOR_EV5, EV5_MASK|MASK_BWX|MASK_MAX },
    { "21164pc",PROCESSOR_EV5, EV5_MASK|MASK_BWX|MASK_MAX },
    { "ev6",	PROCESSOR_EV6, EV6_MASK },
    { "21264",	PROCESSOR_EV6, EV6_MASK },
    { "ev67",	PROCESSOR_EV6, EV6_MASK|MASK_CIX },
    { "21264a",	PROCESSOR_EV6, EV6_MASK|MASK_CIX },
    { 0, 0, 0 }
  };
                  
  /* Unicos/Mk doesn't have shared libraries.  */
  if (TARGET_ABI_UNICOSMK && flag_pic)
    {
      warning ("-f%s ignored for Unicos/Mk (not supported)",
	       (flag_pic > 1) ? "PIC" : "pic");
      flag_pic = 0;
    }

  /* On Unicos/Mk, the native compiler consistenly generates /d suffices for 
     floating-point instructions.  Make that the default for this target.  */
  if (TARGET_ABI_UNICOSMK)
    alpha_fprm = ALPHA_FPRM_DYN;
  else
    alpha_fprm = ALPHA_FPRM_NORM;

  alpha_tp = ALPHA_TP_PROG;
  alpha_fptm = ALPHA_FPTM_N;

  /* We cannot use su and sui qualifiers for conversion instructions on 
     Unicos/Mk.  I'm not sure if this is due to assembler or hardware
     limitations.  Right now, we issue a warning if -mieee is specified
     and then ignore it; eventually, we should either get it right or
     disable the option altogether.  */

  if (TARGET_IEEE)
    {
      if (TARGET_ABI_UNICOSMK)
	warning ("-mieee not supported on Unicos/Mk");
      else
	{
	  alpha_tp = ALPHA_TP_INSN;
	  alpha_fptm = ALPHA_FPTM_SU;
	}
    }

  if (TARGET_IEEE_WITH_INEXACT)
    {
      if (TARGET_ABI_UNICOSMK)
	warning ("-mieee-with-inexact not supported on Unicos/Mk");
      else
	{
	  alpha_tp = ALPHA_TP_INSN;
	  alpha_fptm = ALPHA_FPTM_SUI;
	}
    }

  if (alpha_tp_string)
    {
      if (! strcmp (alpha_tp_string, "p"))
	alpha_tp = ALPHA_TP_PROG;
      else if (! strcmp (alpha_tp_string, "f"))
	alpha_tp = ALPHA_TP_FUNC;
      else if (! strcmp (alpha_tp_string, "i"))
	alpha_tp = ALPHA_TP_INSN;
      else
	error ("bad value `%s' for -mtrap-precision switch", alpha_tp_string);
    }

  if (alpha_fprm_string)
    {
      if (! strcmp (alpha_fprm_string, "n"))
	alpha_fprm = ALPHA_FPRM_NORM;
      else if (! strcmp (alpha_fprm_string, "m"))
	alpha_fprm = ALPHA_FPRM_MINF;
      else if (! strcmp (alpha_fprm_string, "c"))
	alpha_fprm = ALPHA_FPRM_CHOP;
      else if (! strcmp (alpha_fprm_string,"d"))
	alpha_fprm = ALPHA_FPRM_DYN;
      else
	error ("bad value `%s' for -mfp-rounding-mode switch",
	       alpha_fprm_string);
    }

  if (alpha_fptm_string)
    {
      if (strcmp (alpha_fptm_string, "n") == 0)
	alpha_fptm = ALPHA_FPTM_N;
      else if (strcmp (alpha_fptm_string, "u") == 0)
	alpha_fptm = ALPHA_FPTM_U;
      else if (strcmp (alpha_fptm_string, "su") == 0)
	alpha_fptm = ALPHA_FPTM_SU;
      else if (strcmp (alpha_fptm_string, "sui") == 0)
	alpha_fptm = ALPHA_FPTM_SUI;
      else
	error ("bad value `%s' for -mfp-trap-mode switch", alpha_fptm_string);
    }

  alpha_cpu
    = TARGET_CPU_DEFAULT & MASK_CPU_EV6 ? PROCESSOR_EV6
      : (TARGET_CPU_DEFAULT & MASK_CPU_EV5 ? PROCESSOR_EV5 : PROCESSOR_EV4);

  if (alpha_cpu_string)
    {
      for (i = 0; cpu_table [i].name; i++)
	if (! strcmp (alpha_cpu_string, cpu_table [i].name))
	  {
	    alpha_cpu = cpu_table [i].processor;
	    target_flags &= ~ (MASK_BWX | MASK_MAX | MASK_FIX | MASK_CIX
			       | MASK_CPU_EV5 | MASK_CPU_EV6);
	    target_flags |= cpu_table [i].flags;
	    break;
	  }
      if (! cpu_table [i].name)
	error ("bad value `%s' for -mcpu switch", alpha_cpu_string);
    }

  if (alpha_tune_string)
    {
      for (i = 0; cpu_table [i].name; i++)
	if (! strcmp (alpha_tune_string, cpu_table [i].name))
	  {
	    alpha_cpu = cpu_table [i].processor;
	    break;
	  }
      if (! cpu_table [i].name)
	error ("bad value `%s' for -mcpu switch", alpha_tune_string);
    }

  /* Do some sanity checks on the above options.  */

  if (TARGET_ABI_UNICOSMK && alpha_fptm != ALPHA_FPTM_N)
    {
      warning ("trap mode not supported on Unicos/Mk");
      alpha_fptm = ALPHA_FPTM_N;
    }

  if ((alpha_fptm == ALPHA_FPTM_SU || alpha_fptm == ALPHA_FPTM_SUI)
      && alpha_tp != ALPHA_TP_INSN && ! TARGET_CPU_EV6)
    {
      warning ("fp software completion requires -mtrap-precision=i");
      alpha_tp = ALPHA_TP_INSN;
    }

  if (TARGET_CPU_EV6)
    {
      /* Except for EV6 pass 1 (not released), we always have precise
	 arithmetic traps.  Which means we can do software completion
	 without minding trap shadows.  */
      alpha_tp = ALPHA_TP_PROG;
    }

  if (TARGET_FLOAT_VAX)
    {
      if (alpha_fprm == ALPHA_FPRM_MINF || alpha_fprm == ALPHA_FPRM_DYN)
	{
	  warning ("rounding mode not supported for VAX floats");
	  alpha_fprm = ALPHA_FPRM_NORM;
	}
      if (alpha_fptm == ALPHA_FPTM_SUI)
	{
	  warning ("trap mode not supported for VAX floats");
	  alpha_fptm = ALPHA_FPTM_SU;
	}
    }

  {
    char *end;
    int lat;

    if (!alpha_mlat_string)
      alpha_mlat_string = "L1";

    if (ISDIGIT ((unsigned char)alpha_mlat_string[0])
	&& (lat = strtol (alpha_mlat_string, &end, 10), *end == '\0'))
      ;
    else if ((alpha_mlat_string[0] == 'L' || alpha_mlat_string[0] == 'l')
	     && ISDIGIT ((unsigned char)alpha_mlat_string[1])
	     && alpha_mlat_string[2] == '\0')
      {
	static int const cache_latency[][4] = 
	{
	  { 3, 30, -1 },	/* ev4 -- Bcache is a guess */
	  { 2, 12, 38 },	/* ev5 -- Bcache from PC164 LMbench numbers */
	  { 3, 12, 30 },	/* ev6 -- Bcache from DS20 LMbench.  */
	};

	lat = alpha_mlat_string[1] - '0';
	if (lat <= 0 || lat > 3 || cache_latency[alpha_cpu][lat-1] == -1)
	  {
	    warning ("L%d cache latency unknown for %s",
		     lat, alpha_cpu_name[alpha_cpu]);
	    lat = 3;
	  }
	else
	  lat = cache_latency[alpha_cpu][lat-1];
      }
    else if (! strcmp (alpha_mlat_string, "main"))
      {
	/* Most current memories have about 370ns latency.  This is
	   a reasonable guess for a fast cpu.  */
	lat = 150;
      }
    else
      {
	warning ("bad value `%s' for -mmemory-latency", alpha_mlat_string);
	lat = 3;
      }

    alpha_memory_latency = lat;
  }

  /* Default the definition of "small data" to 8 bytes.  */
  if (!g_switch_set)
    g_switch_value = 8;

  /* Infer TARGET_SMALL_DATA from -fpic/-fPIC.  */
  if (flag_pic == 1)
    target_flags |= MASK_SMALL_DATA;
  else if (flag_pic == 2)