mmix.c

Mac OS X 10.4.9 for x86 Source Code gcc 实现源代码

/* Definitions of target machine for GNU compiler, for MMIX.
   Copyright (C) 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   Contributed by Hans-Peter Nilsson ([e-mail])

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.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "hashtab.h"
#include "insn-config.h"
#include "output.h"
#include "flags.h"
#include "tree.h"
#include "function.h"
#include "expr.h"
#include "toplev.h"
#include "recog.h"
#include "ggc.h"
#include "dwarf2.h"
#include "debug.h"
#include "tm_p.h"
#include "integrate.h"
#include "target.h"
#include "target-def.h"
#include "real.h"

/* First some local helper definitions.  */
#define MMIX_FIRST_GLOBAL_REGNUM 32

/* We'd need a current_function_has_landing_pad.  It's marked as such when
   a nonlocal_goto_receiver is expanded.  Not just a C++ thing, but
   mostly.  */
#define MMIX_CFUN_HAS_LANDING_PAD (cfun->machine->has_landing_pad != 0)

/* We have no means to tell DWARF 2 about the register stack, so we need
   to store the return address on the stack if an exception can get into
   this function.  FIXME: Narrow condition.  Before any whole-function
   analysis, regs_ever_live[] isn't initialized.  We know it's up-to-date
   after reload_completed; it may contain incorrect information some time
   before that.  Within a RTL sequence (after a call to start_sequence,
   such as in RTL expanders), leaf_function_p doesn't see all insns
   (perhaps any insn).  But regs_ever_live is up-to-date when
   leaf_function_p () isn't, so we "or" them together to get accurate
   information.  FIXME: Some tweak to leaf_function_p might be
   preferable.  */
#define MMIX_CFUN_NEEDS_SAVED_EH_RETURN_ADDRESS			\
 (flag_exceptions						\
  && ((reload_completed && regs_ever_live[MMIX_rJ_REGNUM])	\
      || !leaf_function_p ()))

#define IS_MMIX_EH_RETURN_DATA_REG(REGNO)	\
 (current_function_calls_eh_return		\
  && (EH_RETURN_DATA_REGNO (0) == REGNO		\
      || EH_RETURN_DATA_REGNO (1) == REGNO	\
      || EH_RETURN_DATA_REGNO (2) == REGNO	\
      || EH_RETURN_DATA_REGNO (3) == REGNO))

/* For the default ABI, we rename registers at output-time to fill the gap
   between the (statically partitioned) saved registers and call-clobbered
   registers.  In effect this makes unused call-saved registers to be used
   as call-clobbered registers.  The benefit comes from keeping the number
   of local registers (value of rL) low, since there's a cost of
   increasing rL and clearing unused (unset) registers with lower numbers.
   Don't translate while outputting the prologue.  */
#define MMIX_OUTPUT_REGNO(N)					\
 (TARGET_ABI_GNU 						\
  || (int) (N) < MMIX_RETURN_VALUE_REGNUM			\
  || (int) (N) > MMIX_LAST_STACK_REGISTER_REGNUM		\
  || cfun == NULL 						\
  || cfun->machine == NULL 					\
  || cfun->machine->in_prologue					\
  ? (N) : ((N) - MMIX_RETURN_VALUE_REGNUM			\
	   + cfun->machine->highest_saved_stack_register + 1))

/* The %d in "POP %d,0".  */
#define MMIX_POP_ARGUMENT()						\
 ((! TARGET_ABI_GNU							\
   && current_function_return_rtx != NULL				\
   && ! current_function_returns_struct)				\
  ? (GET_CODE (current_function_return_rtx) == PARALLEL			\
     ? GET_NUM_ELEM (XVEC (current_function_return_rtx, 0)) : 1)	\
  : 0)

/* The canonical saved comparison operands for non-cc0 machines, set in
   the compare expander.  */
rtx mmix_compare_op0;
rtx mmix_compare_op1;

/* We ignore some options with arguments.  They are passed to the linker,
   but also ends up here because they start with "-m".  We tell the driver
   to store them in a variable we don't inspect.  */
const char *mmix_cc1_ignored_option;

/* Declarations of locals.  */

/* Intermediate for insn output.  */
static int mmix_output_destination_register;

static void mmix_output_shiftvalue_op_from_str
  (FILE *, const char *, HOST_WIDEST_INT);
static void mmix_output_shifted_value (FILE *, HOST_WIDEST_INT);
static void mmix_output_condition (FILE *, rtx, int);
static HOST_WIDEST_INT mmix_intval (rtx);
static void mmix_output_octa (FILE *, HOST_WIDEST_INT, int);
static bool mmix_assemble_integer (rtx, unsigned int, int);
static struct machine_function *mmix_init_machine_status (void);
static void mmix_encode_section_info (tree, rtx, int);
static const char *mmix_strip_name_encoding (const char *);
static void mmix_emit_sp_add (HOST_WIDE_INT offset);
static void mmix_target_asm_function_prologue (FILE *, HOST_WIDE_INT);
static void mmix_target_asm_function_end_prologue (FILE *);
static void mmix_target_asm_function_epilogue (FILE *, HOST_WIDE_INT);
static void mmix_reorg (void);
static void mmix_asm_output_mi_thunk
  (FILE *, tree, HOST_WIDE_INT, HOST_WIDE_INT, tree);
static void mmix_setup_incoming_varargs
  (CUMULATIVE_ARGS *, enum machine_mode, tree, int *, int);
static void mmix_file_start (void);
static void mmix_file_end (void);
static bool mmix_rtx_costs (rtx, int, int, int *);
static rtx mmix_struct_value_rtx (tree, int);
static bool mmix_pass_by_reference (const CUMULATIVE_ARGS *,
				    enum machine_mode, tree, bool);

/* Target structure macros.  Listed by node.  See `Using and Porting GCC'
   for a general description.  */

/* Node: Function Entry */

#undef TARGET_ASM_BYTE_OP
#define TARGET_ASM_BYTE_OP NULL
#undef TARGET_ASM_ALIGNED_HI_OP
#define TARGET_ASM_ALIGNED_HI_OP NULL
#undef TARGET_ASM_ALIGNED_SI_OP
#define TARGET_ASM_ALIGNED_SI_OP NULL
#undef TARGET_ASM_ALIGNED_DI_OP
#define TARGET_ASM_ALIGNED_DI_OP NULL
#undef TARGET_ASM_INTEGER
#define TARGET_ASM_INTEGER mmix_assemble_integer

#undef TARGET_ASM_FUNCTION_PROLOGUE
#define TARGET_ASM_FUNCTION_PROLOGUE mmix_target_asm_function_prologue

#undef TARGET_ASM_FUNCTION_END_PROLOGUE
#define TARGET_ASM_FUNCTION_END_PROLOGUE mmix_target_asm_function_end_prologue

#undef TARGET_ASM_FUNCTION_EPILOGUE
#define TARGET_ASM_FUNCTION_EPILOGUE mmix_target_asm_function_epilogue

#undef TARGET_ENCODE_SECTION_INFO
#define TARGET_ENCODE_SECTION_INFO  mmix_encode_section_info
#undef TARGET_STRIP_NAME_ENCODING
#define TARGET_STRIP_NAME_ENCODING  mmix_strip_name_encoding

#undef TARGET_ASM_OUTPUT_MI_THUNK
#define TARGET_ASM_OUTPUT_MI_THUNK mmix_asm_output_mi_thunk
#undef TARGET_ASM_CAN_OUTPUT_MI_THUNK
#define TARGET_ASM_CAN_OUTPUT_MI_THUNK default_can_output_mi_thunk_no_vcall
#undef TARGET_ASM_FILE_START
#define TARGET_ASM_FILE_START mmix_file_start
#undef TARGET_ASM_FILE_START_FILE_DIRECTIVE
#define TARGET_ASM_FILE_START_FILE_DIRECTIVE true
#undef TARGET_ASM_FILE_END
#define TARGET_ASM_FILE_END mmix_file_end

#undef TARGET_RTX_COSTS
#define TARGET_RTX_COSTS mmix_rtx_costs
#undef TARGET_ADDRESS_COST
#define TARGET_ADDRESS_COST hook_int_rtx_0

#undef TARGET_MACHINE_DEPENDENT_REORG
#define TARGET_MACHINE_DEPENDENT_REORG mmix_reorg

#undef TARGET_PROMOTE_FUNCTION_ARGS
#define TARGET_PROMOTE_FUNCTION_ARGS hook_bool_tree_true
#if 0
/* Apparently not doing TRT if int < register-size.  FIXME: Perhaps
   FUNCTION_VALUE and LIBCALL_VALUE needs tweaking as some ports say.  */
#undef TARGET_PROMOTE_FUNCTION_RETURN
#define TARGET_PROMOTE_FUNCTION_RETURN hook_bool_tree_true
#endif

#undef TARGET_STRUCT_VALUE_RTX
#define TARGET_STRUCT_VALUE_RTX mmix_struct_value_rtx
#undef TARGET_SETUP_INCOMING_VARARGS
#define TARGET_SETUP_INCOMING_VARARGS mmix_setup_incoming_varargs
#undef TARGET_PASS_BY_REFERENCE
#define TARGET_PASS_BY_REFERENCE mmix_pass_by_reference
#undef TARGET_CALLEE_COPIES
#define TARGET_CALLEE_COPIES hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true

struct gcc_target targetm = TARGET_INITIALIZER;

/* Functions that are expansions for target macros.
   See Target Macros in `Using and Porting GCC'.  */

/* OVERRIDE_OPTIONS.  */

void
mmix_override_options (void)
{
  /* Should we err or should we warn?  Hmm.  At least we must neutralize
     it.  For example the wrong kind of case-tables will be generated with
     PIC; we use absolute address items for mmixal compatibility.  FIXME:
     They could be relative if we just elide them to after all pertinent
     labels.  */
  if (flag_pic)
    {
      warning ("-f%s not supported: ignored", (flag_pic > 1) ? "PIC" : "pic");
      flag_pic = 0;
    }
}

/* INIT_EXPANDERS.  */

void
mmix_init_expanders (void)
{
  init_machine_status = mmix_init_machine_status;
}

/* Set the per-function data.  */

static struct machine_function *
mmix_init_machine_status (void)
{
  return ggc_alloc_cleared (sizeof (struct machine_function));
}

/* DATA_ALIGNMENT.
   We have trouble getting the address of stuff that is located at other
   than 32-bit alignments (GETA requirements), so try to give everything
   at least 32-bit alignment.  */

int
mmix_data_alignment (tree type ATTRIBUTE_UNUSED, int basic_align)
{
  if (basic_align < 32)
    return 32;

  return basic_align;
}

/* CONSTANT_ALIGNMENT.  */

int
mmix_constant_alignment (tree constant ATTRIBUTE_UNUSED, int basic_align)
{
  if (basic_align < 32)
    return 32;

  return basic_align;
}

/* LOCAL_ALIGNMENT.  */

int
mmix_local_alignment (tree type ATTRIBUTE_UNUSED, int basic_align)
{
  if (basic_align < 32)
    return 32;

  return basic_align;
}

/* CONDITIONAL_REGISTER_USAGE.  */

void
mmix_conditional_register_usage (void)
{
  int i;

  if (TARGET_ABI_GNU)
    {
      static const int gnu_abi_reg_alloc_order[]
	= MMIX_GNU_ABI_REG_ALLOC_ORDER;

      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
	reg_alloc_order[i] = gnu_abi_reg_alloc_order[i];

      /* Change the default from the mmixware ABI.  For the GNU ABI,
	 $15..$30 are call-saved just as $0..$14.  There must be one
	 call-clobbered local register for the "hole" that holds the
	 number of saved local registers saved by PUSHJ/PUSHGO during the
	 function call, receiving the return value at return.  So best is
	 to use the highest, $31.  It's already marked call-clobbered for
	 the mmixware ABI.  */
      for (i = 15; i <= 30; i++)
	call_used_regs[i] = 0;

      /* "Unfix" the parameter registers.  */
      for (i = MMIX_RESERVED_GNU_ARG_0_REGNUM;
	   i < MMIX_RESERVED_GNU_ARG_0_REGNUM + MMIX_MAX_ARGS_IN_REGS;
	   i++)
	fixed_regs[i] = 0;
    }

  /* Step over the ":" in special register names.  */
  if (! TARGET_TOPLEVEL_SYMBOLS)
    for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
      if (reg_names[i][0] == ':')
	reg_names[i]++;
}

/* LOCAL_REGNO.
   All registers that are part of the register stack and that will be
   saved are local.  */

int
mmix_local_regno (int regno)
{
  return regno <= MMIX_LAST_STACK_REGISTER_REGNUM && !call_used_regs[regno];
}

/* PREFERRED_RELOAD_CLASS.
   We need to extend the reload class of REMAINDER_REG and HIMULT_REG.  */

enum reg_class
mmix_preferred_reload_class (rtx x ATTRIBUTE_UNUSED, enum reg_class class)
{
  /* FIXME: Revisit.  */
  return GET_CODE (x) == MOD && GET_MODE (x) == DImode
    ? REMAINDER_REG : class;
}

/* PREFERRED_OUTPUT_RELOAD_CLASS.
   We need to extend the reload class of REMAINDER_REG and HIMULT_REG.  */

enum reg_class
mmix_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
				    enum reg_class class)
{
  /* FIXME: Revisit.  */
  return GET_CODE (x) == MOD && GET_MODE (x) == DImode
    ? REMAINDER_REG : class;
}

/* SECONDARY_RELOAD_CLASS.
   We need to reload regs of REMAINDER_REG and HIMULT_REG elsewhere.  */

enum reg_class
mmix_secondary_reload_class (enum reg_class class,
			     enum machine_mode mode ATTRIBUTE_UNUSED,
			     rtx x ATTRIBUTE_UNUSED,
			     int in_p ATTRIBUTE_UNUSED)
{
  if (class == REMAINDER_REG
      || class == HIMULT_REG
      || class == SYSTEM_REGS)
    return GENERAL_REGS;

  return NO_REGS;
}

/* CONST_OK_FOR_LETTER_P.  */

int
mmix_const_ok_for_letter_p (HOST_WIDE_INT value, int c)
{
  return
    (c == 'I' ? value >= 0 && value <= 255
     : c == 'J' ? value >= 0 && value <= 65535
     : c == 'K' ? value <= 0 && value >= -255
     : c == 'L' ? mmix_shiftable_wyde_value (value)
     : c == 'M' ? value == 0
     : c == 'N' ? mmix_shiftable_wyde_value (~value)
     : c == 'O' ? (value == 3 || value == 5 || value == 9
		   || value == 17)
     : 0);
}

/* CONST_DOUBLE_OK_FOR_LETTER_P.  */

int
mmix_const_double_ok_for_letter_p (rtx value, int c)
{
  return
    (c == 'G' ? value == CONST0_RTX (GET_MODE (value))
     : 0);
}

/* EXTRA_CONSTRAINT.
   We need this since our constants are not always expressible as
   CONST_INT:s, but rather often as CONST_DOUBLE:s.  */

int
mmix_extra_constraint (rtx x, int c, int strict)
{
  HOST_WIDEST_INT value;

  /* When checking for an address, we need to handle strict vs. non-strict
     register checks.  Don't use address_operand, but instead its
     equivalent (its callee, which it is just a wrapper for),
     memory_operand_p and the strict-equivalent strict_memory_address_p.  */
  if (c == 'U')
    return
      strict
      ? strict_memory_address_p (Pmode, x)
      : memory_address_p (Pmode, x);

  /* R asks whether x is to be loaded with GETA or something else.  Right
     now, only a SYMBOL_REF and LABEL_REF can fit for
     TARGET_BASE_ADDRESSES.

     Only constant symbolic addresses apply.  With TARGET_BASE_ADDRESSES,
     we just allow straight LABEL_REF or SYMBOL_REFs with SYMBOL_REF_FLAG
     set right now; only function addresses and code labels.  If we change
     to let SYMBOL_REF_FLAG be set on other symbols, we have to check
     inside CONST expressions.  When TARGET_BASE_ADDRESSES is not in
     effect, a "raw" constant check together with mmix_constant_address_p
     is all that's needed; we want all constant addresses to be loaded
     with GETA then.  */
  if (c == 'R')
    return
      GET_CODE (x) != CONST_INT && GET_CODE (x) != CONST_DOUBLE
      && mmix_constant_address_p (x)
      && (! TARGET_BASE_ADDRESSES
	  || (GET_CODE (x) == LABEL_REF
	      || (GET_CODE (x) == SYMBOL_REF && SYMBOL_REF_FLAG (x))));

  if (GET_CODE (x) != CONST_DOUBLE || GET_MODE (x) != VOIDmode)
    return 0;