bc-optab.c

gcc库的原代码,对编程有很大帮助.

/* Bytecode conversion definitions for GNU C-compiler.
   Copyright (C) 1993, 1994 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 "tree.h"
#include "rtl.h"
#include "machmode.h"
#include "obstack.h"
#include "bytecode.h"
#include "bc-typecd.h"
#include "bc-opcode.h"
#include "bc-optab.h"

#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free

extern char *xmalloc ();
extern void free ();

/* Table relating interpreter typecodes to machine modes.  */
#define GET_TYPECODE_MODE(CODE) (typecode_mode[((int) CODE)])
enum machine_mode typecode_mode[] = {
#define DEFTYPECODE(CODE, NAME, MODE, TYPE) MODE,
#include "bc-typecd.def"
#undef DEFTYPECODE
};

/* Machine mode to type code map */
static enum typecode signed_mode_to_code_map[MAX_MACHINE_MODE+1];
static enum typecode unsigned_mode_to_code_map[MAX_MACHINE_MODE+1];

#define GET_TYPECODE_SIZE(CODE) GET_MODE_SIZE (GET_TYPECODE_MODE (CODE))

#define BIG_ARBITRARY_NUMBER 100000

/* Table of recipes for conversions among scalar types, to be filled
   in as needed at run time.  */
static struct conversion_recipe
{
  unsigned char *opcodes;	/* Bytecodes to emit in order.  */
  int nopcodes;			/* Count of bytecodes. */
  int cost;			/* A rather arbitrary cost function. */
} conversion_recipe[NUM_TYPECODES][NUM_TYPECODES];

/* Binary operator tables.  */
struct binary_operator optab_plus_expr[] = {
  { addSI, SIcode, SIcode, SIcode },
  { addDI, DIcode, DIcode, DIcode },
  { addSF, SFcode, SFcode, SFcode },
  { addDF, DFcode, DFcode, DFcode },
  { addXF, XFcode, XFcode, XFcode },
  { addPSI, Pcode, Pcode, SIcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_minus_expr[] = {
  { subSI, SIcode, SIcode, SIcode },
  { subDI, DIcode, DIcode, DIcode },
  { subSF, SFcode, SFcode, SFcode },
  { subDF, DFcode, DFcode, DFcode },
  { subXF, XFcode, XFcode, XFcode },
  { subPP, SIcode, Pcode, Pcode },
  { -1, -1, -1, -1 },
};

/* The ordering of the tables for multiplicative operators
   is such that unsigned operations will be preferred to signed
   operations when one argument is unsigned.  */

struct binary_operator optab_mult_expr[] = {
  { mulSU, SUcode, SUcode, SUcode },
  { mulDU, DUcode, DUcode, DUcode },
  { mulSI, SIcode, SIcode, SIcode },
  { mulDI, DIcode, DIcode, DIcode },
  { mulSF, SFcode, SFcode, SFcode },
  { mulDF, DFcode, DFcode, DFcode },
  { mulXF, XFcode, XFcode, XFcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_trunc_div_expr[] = {
  { divSU, SUcode, SUcode, SUcode },
  { divDU, DUcode, DUcode, DUcode },
  { divSI, SIcode, SIcode, SIcode },
  { divDI, DIcode, DIcode, DIcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_trunc_mod_expr[] = {
  { modSU, SUcode, SUcode, SUcode },
  { modDU, DUcode, DUcode, DUcode },
  { modSI, SIcode, SIcode, SIcode },
  { modDI, DIcode, DIcode, DIcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_rdiv_expr[] = {
  { divSF, SFcode, SFcode, SFcode },
  { divDF, DFcode, DFcode, DFcode },
  { divXF, XFcode, XFcode, XFcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_bit_and_expr[] = {
  { andSI, SIcode, SIcode, SIcode },
  { andDI, DIcode, DIcode, DIcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_bit_ior_expr[] = {
  { iorSI, SIcode, SIcode, SIcode },
  { iorDI, DIcode, DIcode, DIcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_bit_xor_expr[] = {
  { xorSI, SIcode, SIcode, SIcode },
  { xorDI, DIcode, DIcode, DIcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_lshift_expr[] = {
  { lshiftSI, SIcode, SIcode, SIcode },
  { lshiftSU, SUcode, SUcode, SIcode },
  { lshiftDI, DIcode, DIcode, SIcode },
  { lshiftDU, DUcode, DUcode, SIcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_rshift_expr[] = {
  { rshiftSI, SIcode, SIcode, SIcode },
  { rshiftSU, SUcode, SUcode, SIcode },
  { rshiftDI, DIcode, DIcode, SIcode },
  { rshiftDU, DUcode, DUcode, SIcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_truth_and_expr[] = {
  { andSI, SIcode, Tcode, Tcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_truth_or_expr[] = {
  { iorSI, SIcode, Tcode, Tcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_lt_expr[] = {
  { ltSI, Tcode, SIcode, SIcode },
  { ltSU, Tcode, SUcode, SUcode },
  { ltDI, Tcode, DIcode, DIcode },
  { ltDU, Tcode, DUcode, DUcode },
  { ltSF, Tcode, SFcode, SFcode },
  { ltDF, Tcode, DFcode, DFcode },
  { ltXF, Tcode, XFcode, XFcode },
  { ltP, Tcode, Pcode, Pcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_le_expr[] = {
  { leSI, Tcode, SIcode, SIcode },
  { leSU, Tcode, SUcode, SUcode },
  { leDI, Tcode, DIcode, DIcode },
  { leDU, Tcode, DUcode, DUcode },
  { leSF, Tcode, SFcode, SFcode },
  { leDF, Tcode, DFcode, DFcode },
  { leXF, Tcode, XFcode, XFcode },
  { leP, Tcode, Pcode, Pcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_ge_expr[] = {
  { geSI, Tcode, SIcode, SIcode },
  { geSU, Tcode, SUcode, SUcode },
  { geDI, Tcode, DIcode, DIcode },
  { geDU, Tcode, DUcode, DUcode },
  { geSF, Tcode, SFcode, SFcode },
  { geDF, Tcode, DFcode, DFcode },
  { geXF, Tcode, XFcode, XFcode },
  { geP, Tcode, Pcode, Pcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_gt_expr[] = {
  { gtSI, Tcode, SIcode, SIcode },
  { gtSU, Tcode, SUcode, SUcode },
  { gtDI, Tcode, DIcode, DIcode },
  { gtDU, Tcode, DUcode, DUcode },
  { gtSF, Tcode, SFcode, SFcode },
  { gtDF, Tcode, DFcode, DFcode },
  { gtXF, Tcode, XFcode, XFcode },
  { gtP, Tcode, Pcode, Pcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_eq_expr[] = {
  { eqSI, Tcode, SIcode, SIcode },
  { eqDI, Tcode, DIcode, DIcode },
  { eqSF, Tcode, SFcode, SFcode },
  { eqDF, Tcode, DFcode, DFcode },
  { eqXF, Tcode, XFcode, XFcode },
  { eqP, Tcode, Pcode, Pcode },
  { -1, -1, -1, -1 },
};

struct binary_operator optab_ne_expr[] = {
  { neSI, Tcode, SIcode, SIcode },
  { neDI, Tcode, DIcode, DIcode },
  { neSF, Tcode, SFcode, SFcode },
  { neDF, Tcode, DFcode, DFcode },
  { neXF, Tcode, XFcode, XFcode },
  { neP, Tcode, Pcode, Pcode },
  { -1, -1, -1, -1 },
};

/* Unary operator tables.  */
struct unary_operator optab_negate_expr[] = {
  { negSI, SIcode, SIcode },
  { negDI, DIcode, DIcode },
  { negSF, SFcode, SFcode },
  { negDF, DFcode, DFcode },
  { negXF, XFcode, XFcode },
  { -1, -1, -1 },
};

struct unary_operator optab_bit_not_expr[] = {
  { notSI, SIcode, SIcode },
  { notDI, DIcode, DIcode },
  { -1, -1, -1 },
};

struct unary_operator optab_truth_not_expr[] = {
  { notT, SIcode, SIcode },
  { -1, -1, -1 },
};

/* Increment operator tables.  */
struct increment_operator optab_predecrement_expr[] = {
  { predecQI, QIcode },
  { predecQI, QUcode },
  { predecHI, HIcode },
  { predecHI, HUcode },
  { predecSI, SIcode },
  { predecSI, SUcode },
  { predecDI, DIcode },
  { predecDI, DUcode },
  { predecP, Pcode },
  { predecSF, SFcode },
  { predecDF, DFcode },
  { predecXF, XFcode },
  { -1, -1 },
};

struct increment_operator optab_preincrement_expr[] = {
  { preincQI, QIcode },
  { preincQI, QUcode },
  { preincHI, HIcode },
  { preincHI, HUcode },
  { preincSI, SIcode },
  { preincSI, SUcode },
  { preincDI, DIcode },
  { preincDI, DUcode },
  { preincP, Pcode },
  { preincSF, SFcode },
  { preincDF, DFcode },
  { preincXF, XFcode },
  { -1, -1 },
};

struct increment_operator optab_postdecrement_expr[] = {
  { postdecQI, QIcode },
  { postdecQI, QUcode },
  { postdecHI, HIcode },
  { postdecHI, HUcode },
  { postdecSI, SIcode },
  { postdecSI, SUcode },
  { postdecDI, DIcode },
  { postdecDI, DUcode },
  { postdecP, Pcode },
  { postdecSF, SFcode },
  { postdecDF, DFcode },
  { postdecXF, XFcode },
  { -1, -1 },
};

struct increment_operator optab_postincrement_expr[] = {
  { postincQI, QIcode },
  { postincQI, QUcode },
  { postincHI, HIcode },
  { postincHI, HUcode },
  { postincSI, SIcode },
  { postincSI, SUcode },
  { postincDI, DIcode },
  { postincDI, DUcode },
  { postincP, Pcode },
  { postincSF, SFcode },
  { postincDF, DFcode },
  { postincXF, XFcode },
  { -1, -1 },
};

/* Table of conversions supported by the interpreter.  */
static struct conversion_info
{
  enum bytecode_opcode opcode;	/*  here indicates the conversion needs no opcode.  */
  enum typecode from;
  enum typecode to;
  int cost;			/* 1 for no-op conversions, 2 for widening conversions,
				   4 for int/float conversions, 8 for narrowing conversions.  */
} conversion_info[] = {
  { -1, QIcode, QUcode, 1 },
  { -1, HIcode, HUcode, 1 },
  { -1, SIcode, SUcode, 1 },
  { -1, DIcode, DUcode, 1 },
  { -1, QUcode, QIcode, 1 },
  { -1, HUcode, HIcode, 1 },
  { -1, SUcode, SIcode, 1 },
  { -1, DUcode, DIcode, 1 },
  { -1, Tcode, SIcode, 1 },
  { convertQIHI, QIcode, HIcode, 2 },
  { convertQUHU, QUcode, HUcode, 2 },
  { convertQUSU, QUcode, SUcode, 2 },
  { convertHISI, HIcode, SIcode, 2 },
  { convertHUSU, HUcode, SUcode, 2 },
  { convertSIDI, SIcode, DIcode, 2 },
  { convertSUDU, SUcode, DUcode, 2 },
  { convertSFDF, SFcode, DFcode, 2 },
  { convertDFXF, DFcode, XFcode, 2 },
  { convertHIQI, HIcode, QIcode, 8 },
  { convertSIQI, SIcode, QIcode, 8 },
  { convertSIHI, SIcode, HIcode, 8 },
  { convertSUQU, SUcode, QUcode, 8 },
  { convertDISI, DIcode, SIcode, 8 },
  { convertDFSF, DFcode, SFcode, 8 },
  { convertXFDF, XFcode, DFcode, 8 },
  { convertPSI, Pcode, SIcode, 2 },
  { convertSIP, SIcode, Pcode, 2 },
  { convertSIT, SIcode, Tcode, 2 },
  { convertDIT, DIcode, Tcode, 2 },
  { convertSFT, SFcode, Tcode, 2 },
  { convertDFT, DFcode, Tcode, 2 },
  { convertXFT, XFcode, Tcode, 2 },
  { convertQISI, QIcode, SIcode, 2 },
  { convertPT, Pcode, Tcode, 2 },
  { convertSISF, SIcode, SFcode, 4 },
  { convertSIDF, SIcode, DFcode, 4 },
  { convertSIXF, SIcode, XFcode, 4 },
  { convertSUSF, SUcode, SFcode, 4 },
  { convertSUDF, SUcode, DFcode, 4 },
  { convertSUXF, SUcode, XFcode, 4 },
  { convertDISF, DIcode, SFcode, 4 },
  { convertDIDF, DIcode, DFcode, 4 },
  { convertDIXF, DIcode, XFcode, 4 },
  { convertDUSF, DUcode, SFcode, 4 },
  { convertDUDF, DUcode, DFcode, 4 },
  { convertDUXF, DUcode, XFcode, 4 },
  { convertSFSI, SFcode, SIcode, 4 },
  { convertDFSI, DFcode, SIcode, 4 },
  { convertXFSI, XFcode, SIcode, 4 },
  { convertSFSU, SFcode, SUcode, 4 },
  { convertDFSU, DFcode, SUcode, 4 },
  { convertXFSU, XFcode, SUcode, 4 },
  { convertSFDI, SFcode, DIcode, 4 },
  { convertDFDI, DFcode, DIcode, 4 },
  { convertXFDI, XFcode, DIcode, 4 },
  { convertSFDU, SFcode, DUcode, 4 },
  { convertDFDU, DFcode, DUcode, 4 },
  { convertXFDU, XFcode, DUcode, 4 },
  { convertSIQI, SIcode, QIcode, 8 },
};

#define NUM_CONVERSIONS (sizeof conversion_info / sizeof (struct conversion_info))

/* List form of a conversion recipe.  */
struct conversion_list
{
  enum bytecode_opcode opcode;