path: root/gcc/read-rtl.c

/* RTL reader for GNU C Compiler.
   Copyright (C) 1987, 1988, 1991, 1994, 1997, 1998, 1999, 2000, 2001
   Free Software Foundation, Inc.

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 "hconfig.h"
#include "system.h"
#include "rtl.h"
#include "obstack.h"
#include "hashtab.h"

#ifndef ISDIGIT
#include <ctype.h>
#define ISDIGIT isdigit
#define ISSPACE isspace
#endif

#define	obstack_chunk_alloc	xmalloc
#define	obstack_chunk_free	free

static htab_t md_constants;

static void fatal_with_file_and_line PARAMS ((FILE *, const char *, ...))
  ATTRIBUTE_PRINTF_2 ATTRIBUTE_NORETURN;
static void fatal_expected_char PARAMS ((FILE *, int, int)) ATTRIBUTE_NORETURN;
static void read_name		PARAMS ((char *, FILE *));
static char *read_string	PARAMS ((struct obstack *, FILE *, int));
static char *read_quoted_string	PARAMS ((struct obstack *, FILE *));
static char *read_braced_string	PARAMS ((struct obstack *, FILE *));
static void read_escape		PARAMS ((struct obstack *, FILE *));
static unsigned def_hash PARAMS ((const void *));
static int def_name_eq_p PARAMS ((const void *, const void *));
static void read_constants PARAMS ((FILE *infile, char *tmp_char));
static void validate_const_int PARAMS ((FILE *, const char *));

/* Subroutines of read_rtx.  */

/* The current line number for the file.  */
int read_rtx_lineno = 1;

/* The filename for aborting with file and line.  */
const char *read_rtx_filename = "<unknown>";

static void
fatal_with_file_and_line VPARAMS ((FILE *infile, const char *msg, ...))
{
  char context[64];
  size_t i;
  int c;

  VA_OPEN (ap, msg);
  VA_FIXEDARG (ap, FILE *, infile);
  VA_FIXEDARG (ap, const char *, msg);

  fprintf (stderr, "%s:%d: ", read_rtx_filename, read_rtx_lineno);
  vfprintf (stderr, msg, ap);
  putc ('\n', stderr);

  /* Gather some following context.  */
  for (i = 0; i < sizeof(context)-1; ++i)
    {
      c = getc (infile);
      if (c == EOF)
	break;
      if (c == '\r' || c == '\n')
	break;
      context[i] = c;
    }
  context[i] = '\0';

  fprintf (stderr, "%s:%d: following context is `%s'\n",
	   read_rtx_filename, read_rtx_lineno, context);

  VA_CLOSE (ap);
  exit (1);
}

/* Dump code after printing a message.  Used when read_rtx finds
   invalid data.  */

static void
fatal_expected_char (infile, expected_c, actual_c)
     FILE *infile;
     int expected_c, actual_c;
{
  fatal_with_file_and_line (infile, "expected character `%c', found `%c'",
			    expected_c, actual_c);
}

/* Read chars from INFILE until a non-whitespace char
   and return that.  Comments, both Lisp style and C style,
   are treated as whitespace.
   Tools such as genflags use this function.  */

int
read_skip_spaces (infile)
     FILE *infile;
{
  int c;

  while (1)
    {
      c = getc (infile);
      switch (c)
	{
	case '\n':
	  read_rtx_lineno++;
	  break;

	case ' ': case '\t': case '\f': case '\r':
	  break;

	case ';':
	  do
	    c = getc (infile);
	  while (c != '\n' && c != EOF);
	  read_rtx_lineno++;
	  break;

	case '/':
	  {
	    int prevc;
	    c = getc (infile);
	    if (c != '*')
	      fatal_expected_char (infile, '*', c);

	    prevc = 0;
	    while ((c = getc (infile)) && c != EOF)
	      {
		if (c == '\n')
		   read_rtx_lineno++;
	        else if (prevc == '*' && c == '/')
		  break;
	        prevc = c;
	      }
	  }
	  break;

	default:
	  return c;
	}
    }
}

/* Read an rtx code name into the buffer STR[].
   It is terminated by any of the punctuation chars of rtx printed syntax.  */

static void
read_name (str, infile)
     char *str;
     FILE *infile;
{
  char *p;
  int c;

  c = read_skip_spaces (infile);

  p = str;
  while (1)
    {
      if (c == ' ' || c == '\n' || c == '\t' || c == '\f' || c == '\r')
	break;
      if (c == ':' || c == ')' || c == ']' || c == '"' || c == '/'
	  || c == '(' || c == '[')
	{
	  ungetc (c, infile);
	  break;
	}
      *p++ = c;
      c = getc (infile);
    }
  if (p == str)
    fatal_with_file_and_line (infile, "missing name or number");
  if (c == '\n')
    read_rtx_lineno++;

  *p = 0;

  if (md_constants)
    {
      /* Do constant expansion.  */
      struct md_constant *def;

      p = str;
      do
	{
	  struct md_constant tmp_def;

	  tmp_def.name = p;
	  def = htab_find (md_constants, &tmp_def);
	  if (def)
	    p = def->value;
	} while (def);
      if (p != str)
	strcpy (str, p);
    }
}

/* Subroutine of the string readers.  Handles backslash escapes.
   Caller has read the backslash, but not placed it into the obstack.  */
static void
read_escape (ob, infile)
     struct obstack *ob;
     FILE *infile;
{
  int c = getc (infile);

  switch (c)
    {
      /* Backslash-newline is replaced by nothing, as in C.  */
    case '\n':
      read_rtx_lineno++;
      return;

      /* \" \' \\ are replaced by the second character.  */
    case '\\':
    case '"':
    case '\'':
      break;

      /* Standard C string escapes:
	 \a \b \f \n \r \t \v
	 \[0-7] \x
	 all are passed through to the output string unmolested.
	 In normal use these wind up in a string constant processed
	 by the C compiler, which will translate them appropriately.
	 We do not bother checking that \[0-7] are followed by up to
	 two octal digits, or that \x is followed by N hex digits.
	 \? \u \U are left out because they are not in traditional C.  */
    case 'a': case 'b': case 'f': case 'n': case 'r': case 't': case 'v':
    case '0': case '1': case '2': case '3': case '4': case '5': case '6':
    case '7': case 'x':
      obstack_1grow (ob, '\\');
      break;

      /* \; makes stuff for a C string constant containing
	 newline and tab.  */
    case ';':
      obstack_grow (ob, "\\n\\t", 4);
      return;

      /* pass anything else through, but issue a warning.  */
    default:
      fprintf (stderr, "%s:%d: warning: unrecognized escape \\%c\n",
	       read_rtx_filename, read_rtx_lineno, c);
      obstack_1grow (ob, '\\');
      break;
    }

  obstack_1grow (ob, c);
}
      

/* Read a double-quoted string onto the obstack.  Caller has scanned
   the leading quote.  */
static char *
read_quoted_string (ob, infile)
     struct obstack *ob;
     FILE *infile;
{
  int c;

  while (1)
    {
      c = getc (infile); /* Read the string  */
      if (c == '\n')
	read_rtx_lineno++;
      else if (c == '\\')
	{
	  read_escape (ob, infile);
	  continue;
	}
      else if (c == '"')
	break;

      obstack_1grow (ob, c);
    }

  obstack_1grow (ob, 0);
  return obstack_finish (ob);
}

/* Read a braced string (a la Tcl) onto the obstack.  Caller has
   scanned the leading brace.  Note that unlike quoted strings,
   the outermost braces _are_ included in the string constant.  */
static char *
read_braced_string (ob, infile)
     struct obstack *ob;
     FILE *infile;
{
  int c;
  int brace_depth = 1;  /* caller-processed */

  obstack_1grow (ob, '{');
  while (brace_depth)
    {
      c = getc (infile); /* Read the string  */
      if (c == '\n')
	read_rtx_lineno++;
      else if (c == '{')
	brace_depth++;
      else if (c == '}')
	brace_depth--;
      else if (c == '\\')
	{
	  read_escape (ob, infile);
	  continue;
	}

      obstack_1grow (ob, c);
    }
      
  obstack_1grow (ob, 0);
  return obstack_finish (ob);
}

/* Read some kind of string constant.  This is the high-level routine
   used by read_rtx.  It handles surrounding parentheses, leading star,
   and dispatch to the appropriate string constant reader.  */

static char *
read_string (ob, infile, star_if_braced)
     struct obstack *ob;
     FILE *infile;
     int star_if_braced;
{
  char *stringbuf;
  int saw_paren = 0;
  int c;

  c = read_skip_spaces (infile);
  if (c == '(')
    {
      saw_paren = 1;
      c = read_skip_spaces (infile);
    }

  if (c == '"')
    stringbuf = read_quoted_string (ob, infile);
  else if (c == '{')
    {
      if (star_if_braced)
	obstack_1grow (ob, '*');
      stringbuf = read_braced_string (ob, infile);
    }
  else
    fatal_with_file_and_line (infile, "expected `\"' or `{', found `%c'", c);
       
  if (saw_paren)
    {
      c = read_skip_spaces (infile);
      if (c != ')')
	fatal_expected_char (infile, ')', c);
    }

  return stringbuf;
}

/* Provide a version of a function to read a long long if the system does
   not provide one.  */
#if HOST_BITS_PER_WIDE_INT > HOST_BITS_PER_LONG && !defined(HAVE_ATOLL) && !defined(HAVE_ATOQ)
HOST_WIDE_INT
atoll(p)
    const char *p;
{
  int neg = 0;
  HOST_WIDE_INT tmp_wide;

  while (ISSPACE(*p))
    p++;
  if (*p == '-')
    neg = 1, p++;
  else if (*p == '+')
    p++;

  tmp_wide = 0;
  while (ISDIGIT(*p))
    {
      HOST_WIDE_INT new_wide = tmp_wide*10 + (*p - '0');
      if (new_wide < tmp_wide)
	{
	  /* Return INT_MAX equiv on overflow.  */
	  tmp_wide = (~(unsigned HOST_WIDE_INT)0) >> 1;
	  break;
	}
      tmp_wide = new_wide;
      p++;
    }

  if (neg)
    tmp_wide = -tmp_wide;
  return tmp_wide;
}
#endif

/* Given a constant definition, return a hash code for its name.  */
static unsigned
def_hash (def)
     const void *def;
{
  unsigned result, i;
  const char *string = ((const struct md_constant *)def)->name;

  for (result = i = 0;*string++ != '\0'; i++)
    result += ((unsigned char) *string << (i % CHAR_BIT));
  return result;
}

/* Given two constant definitions, return true if they have the same name.  */
static int
def_name_eq_p (def1, def2)
     const void *def1, *def2;
{
  return ! strcmp (((const struct md_constant *)def1)->name,
		   ((const struct md_constant *)def2)->name);
}

/* INFILE is a FILE pointer to read text from.  TMP_CHAR is a buffer suitable
   to read a name or number into.  Process a define_constants directive,
   starting with the optional space after the "define_constants".  */
static void
read_constants (infile, tmp_char)
     FILE *infile;
     char *tmp_char;
{
  int c;
  htab_t defs;

  c = read_skip_spaces (infile);
  if (c != '[')
    fatal_expected_char (infile, '[', c);
  defs = md_constants;
  if (! defs)
    defs = htab_create (32, def_hash, def_name_eq_p, (htab_del) 0);
  /* Disable constant expansion during definition processing.  */
  md_constants = 0;
  while ( (c = read_skip_spaces (infile)) != ']')
    {
      struct md_constant *def;
      void **entry_ptr;

      if (c != '(')
	fatal_expected_char (infile, '(', c);
      def = xmalloc (sizeof (struct md_constant));
      def->name = tmp_char;
      read_name (tmp_char, infile);
      entry_ptr = htab_find_slot (defs, def, TRUE);
      if (! *entry_ptr)
	def->name = xstrdup (tmp_char);
      c = read_skip_spaces (infile);
      ungetc (c, infile);
      read_name (tmp_char, infile);
      if (! *entry_ptr)
	{
	  def->value = xstrdup (tmp_char);
	  *entry_ptr = def;
	}
      else
	{
	  def = *entry_ptr;
	  if (strcmp (def->value, tmp_char))
	    fatal_with_file_and_line (infile,
				      "redefinition of %s, was %s, now %s",
				      def->name, def->value, tmp_char);
	}
      c = read_skip_spaces (infile);
      if (c != ')')
	fatal_expected_char (infile, ')', c);
    }
  md_constants = defs;
  c = read_skip_spaces (infile);
  if (c != ')')
    fatal_expected_char (infile, ')', c);
}

/* For every constant definition, call CALLBACK with two arguments:
   a pointer a pointer to the constant definition and INFO.
   Stops when CALLBACK returns zero.  */
void
traverse_md_constants (callback, info)
     htab_trav callback;
     void *info;
{
  if (md_constants)
    htab_traverse (md_constants, callback, info);
}

static void
validate_const_int (infile, string)
     FILE *infile;
     const char *string;
{
  const char *cp;
  int valid = 1;

  cp = string;
  while (*cp && ISSPACE(*cp))
    cp++;
  if (*cp == '-' || *cp == '+')
    cp++;
  if (*cp == 0)
    valid = 0;
  for (; *cp; cp++)
    if (! ISDIGIT (*cp))
      valid = 0;
  if (!valid)
    fatal_with_file_and_line (infile, "invalid decimal constant \"%s\"\n", string);
}

/* Read an rtx in printed representation from INFILE
   and return an actual rtx in core constructed accordingly.
   read_rtx is not used in the compiler proper, but rather in
   the utilities gen*.c that construct C code from machine descriptions.  */

rtx
read_rtx (infile)
     FILE *infile;
{
  int i, j;
  RTX_CODE tmp_code;
  const char *format_ptr;
  /* tmp_char is a buffer used for reading decimal integers
     and names of rtx types and machine modes.
     Therefore, 256 must be enough.  */
  char tmp_char[256];
  rtx return_rtx;
  int c;
  int tmp_int;
  HOST_WIDE_INT tmp_wide;

  /* Obstack used for allocating RTL objects.  */
  static struct obstack rtl_obstack;
  static int initialized;

  /* Linked list structure for making RTXs: */
  struct rtx_list
    {
      struct rtx_list *next;
      rtx value;		/* Value of this node.  */
    };

  if (!initialized) {
    obstack_init (&rtl_obstack);
    initialized = 1;
  }

again:
  c = read_skip_spaces (infile); /* Should be open paren.  */
  if (c != '(')
    fatal_expected_char (infile, '(', c);

  read_name (tmp_char, infile);

  tmp_code = UNKNOWN;

  if (! strcmp (tmp_char, "define_constants"))
    {
      read_constants (infile, tmp_char);
      goto again;
    }
  for (i = 0; i < NUM_RTX_CODE; i++)
    if (! strcmp (tmp_char, GET_RTX_NAME (i)))
      {
	tmp_code = (RTX_CODE) i;	/* get value for name */
	break;
      }

  if (tmp_code == UNKNOWN)
    fatal_with_file_and_line (infile, "unknown rtx code `%s'", tmp_char);

  /* (NIL) stands for an expression that isn't there.  */
  if (tmp_code == NIL)
    {
      /* Discard the closeparen.  */
      while ((c = getc (infile)) && c != ')')
	;

      return 0;
    }

  /* If we end up with an insn expression then we free this space below.  */
  return_rtx = rtx_alloc (tmp_code);
  format_ptr = GET_RTX_FORMAT (GET_CODE (return_rtx));

  /* If what follows is `: mode ', read it and
     store the mode in the rtx.  */

  i = read_skip_spaces (infile);
  if (i == ':')
    {
      read_name (tmp_char, infile);
      for (j = 0; j < NUM_MACHINE_MODES; j++)
	if (! strcmp (GET_MODE_NAME (j), tmp_char))
	  break;

      if (j == MAX_MACHINE_MODE)
	fatal_with_file_and_line (infile, "unknown mode `%s'", tmp_char);

      PUT_MODE (return_rtx, (enum machine_mode) j);
    }
  else
    ungetc (i, infile);

  for (i = 0; i < GET_RTX_LENGTH (GET_CODE (return_rtx)); i++)
    switch (*format_ptr++)
      {
	/* 0 means a field for internal use only.
	   Don't expect it to be present in the input.  */
      case '0':
	break;

      case 'e':
      case 'u':
	XEXP (return_rtx, i) = read_rtx (infile);
	break;

      case 'V':
	/* 'V' is an optional vector: if a closeparen follows,
	   just store NULL for this element.  */
	c = read_skip_spaces (infile);
	ungetc (c, infile);
	if (c == ')')
	  {
	    XVEC (return_rtx, i) = 0;
	    break;
 	  }
	/* Now process the vector.  */

      case 'E':
	{
	  /* Obstack to store scratch vector in.  */
	  struct obstack vector_stack;
	  int list_counter = 0;
	  rtvec return_vec = NULL_RTVEC;

	  c = read_skip_spaces (infile);
	  if (c != '[')
	    fatal_expected_char (infile, '[', c);

	  /* add expressions to a list, while keeping a count */
	  obstack_init (&vector_stack);
	  while ((c = read_skip_spaces (infile)) && c != ']')
	    {
	      ungetc (c, infile);
	      list_counter++;
	      obstack_ptr_grow (&vector_stack, (PTR) read_rtx (infile));
	    }
	  if (list_counter > 0)
	    {
	      return_vec = rtvec_alloc (list_counter);
	      memcpy (&return_vec->elem[0], obstack_finish (&vector_stack),
		      list_counter * sizeof (rtx));
	    }
	  XVEC (return_rtx, i) = return_vec;
	  obstack_free (&vector_stack, NULL);
	  /* close bracket gotten */
	}
	break;

      case 'S':
	/* 'S' is an optional string: if a closeparen follows,
	   just store NULL for this element.  */
	c = read_skip_spaces (infile);
	ungetc (c, infile);
	if (c == ')')
	  {
	    XSTR (return_rtx, i) = 0;
	    break;
	  }

      case 'T':
      case 's':
	{
	  char *stringbuf;

	  /* The output template slot of a DEFINE_INSN,
	     DEFINE_INSN_AND_SPLIT, or DEFINE_PEEPHOLE automatically
	     gets a star inserted as its first character, if it is
	     written with a brace block instead of a string constant.  */
	  int star_if_braced = (format_ptr[-1] == 'T');
	    
	  stringbuf = read_string (&rtl_obstack, infile, star_if_braced);

	  /* For insn patterns, we want to provide a default name
	     based on the file and line, like "*foo.md:12", if the
	     given name is blank.  These are only for define_insn and
	     define_insn_and_split, to aid debugging.  */
	  if (*stringbuf == '\0'
	      && i == 0
	      && (GET_CODE (return_rtx) == DEFINE_INSN
		  || GET_CODE (return_rtx) == DEFINE_INSN_AND_SPLIT))
	    {
	      char line_name[20];
	      const char *fn = (read_rtx_filename ? read_rtx_filename : "rtx");
	      const char *slash;
	      for (slash = fn; *slash; slash ++)
		if (*slash == '/' || *slash == '\\' || *slash == ':')
		  fn = slash + 1;
	      obstack_1grow (&rtl_obstack, '*');
	      obstack_grow (&rtl_obstack, fn, strlen (fn));
	      sprintf (line_name, ":%d", read_rtx_lineno);
	      obstack_grow (&rtl_obstack, line_name, strlen (line_name)+1);
	      stringbuf = (char *) obstack_finish (&rtl_obstack);
	    }

	  if (star_if_braced)
	    XTMPL (return_rtx, i) = stringbuf;
	  else
	    XSTR (return_rtx, i) = stringbuf;
	}
	break;

      case 'w':
	read_name (tmp_char, infile);
	validate_const_int(infile, tmp_char);
#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_INT
	tmp_wide = atoi (tmp_char);
#else
#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_LONG
	tmp_wide = atol (tmp_char);
#else
	/* Prefer atoll over atoq, since the former is in the ISO C99 standard.
	   But prefer not to use our hand-rolled function above either.  */
#if defined(HAVE_ATOLL) || !defined(HAVE_ATOQ)
	tmp_wide = atoll (tmp_char);
#else
	tmp_wide = atoq (tmp_char);
#endif
#endif
#endif
	XWINT (return_rtx, i) = tmp_wide;
	break;

      case 'i':
      case 'n':
	read_name (tmp_char, infile);
	validate_const_int(infile, tmp_char);
	tmp_int = atoi (tmp_char);
	XINT (return_rtx, i) = tmp_int;
	break;

      default:
	fprintf (stderr,
		 "switch format wrong in rtl.read_rtx(). format was: %c.\n",
		 format_ptr[-1]);
	fprintf (stderr, "\tfile position: %ld\n", ftell (infile));
	abort ();
      }

  c = read_skip_spaces (infile);
  if (c != ')')
    fatal_expected_char (infile, ')', c);

  return return_rtx;
}