varasm.c

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{
#if defined (EXCEPTION_SECTION)
  EXCEPTION_SECTION ();
#else
#ifdef ASM_OUTPUT_SECTION_NAME
  named_section (NULL_TREE, ".gcc_except_table", 0);
#else
  if (flag_pic)
    data_section ();
  else
    readonly_data_section ();
#endif
#endif
}

/* Create the rtl to represent a function, for a function definition.
   DECL is a FUNCTION_DECL node which describes which function.
   The rtl is stored into DECL.  */

void
make_function_rtl (decl)
     tree decl;
{
  char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
  char *new_name = name;

  if (output_bytecode)
    {
      if (DECL_RTL (decl) == 0)
	DECL_RTL (decl) = bc_gen_rtx (name, 0, (struct bc_label *) 0);
      
      /* Record that at least one function has been defined.  */
      function_defined = 1;
      return;
    }

  /* Rename a nested function to avoid conflicts.  */
  if (decl_function_context (decl) != 0
      && DECL_INITIAL (decl) != 0
      && DECL_RTL (decl) == 0)
    {
      char *label;

      name = IDENTIFIER_POINTER (DECL_NAME (decl));
      ASM_FORMAT_PRIVATE_NAME (label, name, var_labelno);
      name = obstack_copy0 (saveable_obstack, label, strlen (label));
      var_labelno++;
    }
  else
    {
      /* When -fprefix-function-name is used, every function name is
         prefixed.  Even static functions are prefixed because they
         could be declared latter.  Note that a nested function name
         is not prefixed.  */
      if (flag_prefix_function_name)
        {
          new_name = (char *) alloca (strlen (name) + CHKR_PREFIX_SIZE + 1);
          strcpy (new_name, CHKR_PREFIX);
          strcpy (new_name + CHKR_PREFIX_SIZE, name);
          name = obstack_copy0 (saveable_obstack, new_name, strlen (new_name));
        }
    }

  if (DECL_RTL (decl) == 0)
    {
      DECL_RTL (decl)
	= gen_rtx (MEM, DECL_MODE (decl),
		   gen_rtx (SYMBOL_REF, Pmode, name));

      /* Optionally set flags or add text to the name to record information
	 such as that it is a function name.  If the name is changed, the macro
	 ASM_OUTPUT_LABELREF will have to know how to strip this information.  */
#ifdef ENCODE_SECTION_INFO
      ENCODE_SECTION_INFO (decl);
#endif
    }

  /* Record at least one function has been defined.  */
  function_defined = 1;
}

/* Create the DECL_RTL for a declaration for a static or external
   variable or static or external function.
   ASMSPEC, if not 0, is the string which the user specified
   as the assembler symbol name.
   TOP_LEVEL is nonzero if this is a file-scope variable.
   This is never called for PARM_DECLs.  */

static void
bc_make_decl_rtl (decl, asmspec, top_level)
     tree decl;
     char *asmspec;
     int top_level;
{
  register char *name = TREE_STRING_POINTER (DECL_ASSEMBLER_NAME (decl));

  if (DECL_RTL (decl) == 0)
    {
      /* Print an error message for register variables.  */
      if (DECL_REGISTER (decl))
	error ("global register variables not supported in the interpreter");

      /* Handle ordinary static variables and functions.  */
      if (DECL_RTL (decl) == 0)
	{
	  /* Can't use just the variable's own name for a variable
	     whose scope is less than the whole file.
	     Concatenate a distinguishing number.  */
	  if (!top_level && !TREE_PUBLIC (decl) && asmspec == 0)
	    {
	      char *label;

	      ASM_FORMAT_PRIVATE_NAME (label, name, var_labelno);
	      name = obstack_copy0 (saveable_obstack, label, strlen (label));
	      var_labelno++;
	    }

	  DECL_RTL (decl) = bc_gen_rtx (name, 0, (struct bc_label *) 0);
	}
    }
}

/* Given NAME, a putative register name, discard any customary prefixes.  */

static char *
strip_reg_name (name)
     char *name;
{
#ifdef REGISTER_PREFIX
  if (!strncmp (name, REGISTER_PREFIX, strlen (REGISTER_PREFIX)))
    name += strlen (REGISTER_PREFIX);
#endif
  if (name[0] == '%' || name[0] == '#')
    name++;
  return name;
}

/* Decode an `asm' spec for a declaration as a register name.
   Return the register number, or -1 if nothing specified,
   or -2 if the ASMSPEC is not `cc' or `memory' and is not recognized,
   or -3 if ASMSPEC is `cc' and is not recognized,
   or -4 if ASMSPEC is `memory' and is not recognized.
   Accept an exact spelling or a decimal number.
   Prefixes such as % are optional.  */

int
decode_reg_name (asmspec)
     char *asmspec;
{
  if (asmspec != 0)
    {
      int i;

      /* Get rid of confusing prefixes.  */
      asmspec = strip_reg_name (asmspec);
	
      /* Allow a decimal number as a "register name".  */
      for (i = strlen (asmspec) - 1; i >= 0; i--)
	if (! (asmspec[i] >= '0' && asmspec[i] <= '9'))
	  break;
      if (asmspec[0] != 0 && i < 0)
	{
	  i = atoi (asmspec);
	  if (i < FIRST_PSEUDO_REGISTER && i >= 0)
	    return i;
	  else
	    return -2;
	}

      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
	if (reg_names[i][0]
	    && ! strcmp (asmspec, strip_reg_name (reg_names[i])))
	  return i;

#ifdef ADDITIONAL_REGISTER_NAMES
      {
	static struct { char *name; int number; } table[]
	  = ADDITIONAL_REGISTER_NAMES;

	for (i = 0; i < sizeof (table) / sizeof (table[0]); i++)
	  if (! strcmp (asmspec, table[i].name))
	    return table[i].number;
      }
#endif /* ADDITIONAL_REGISTER_NAMES */

      if (!strcmp (asmspec, "memory"))
	return -4;

      if (!strcmp (asmspec, "cc"))
	return -3;

      return -2;
    }

  return -1;
}

/* Create the DECL_RTL for a declaration for a static or external variable
   or static or external function.
   ASMSPEC, if not 0, is the string which the user specified
   as the assembler symbol name.
   TOP_LEVEL is nonzero if this is a file-scope variable.

   This is never called for PARM_DECL nodes.  */

void
make_decl_rtl (decl, asmspec, top_level)
     tree decl;
     char *asmspec;
     int top_level;
{
  register char *name = 0;
  int reg_number;

  if (output_bytecode)
    {
      bc_make_decl_rtl (decl, asmspec, top_level);
      return;
    }

  reg_number = decode_reg_name (asmspec);

  if (DECL_ASSEMBLER_NAME (decl) != NULL_TREE)
    name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));

  if (reg_number == -2)
    {
      /* ASMSPEC is given, and not the name of a register.  */
      name = (char *) obstack_alloc (saveable_obstack,
				     strlen (asmspec) + 2);
      name[0] = '*';
      strcpy (&name[1], asmspec);
    }

  /* For a duplicate declaration, we can be called twice on the
     same DECL node.  Don't discard the RTL already made.  */
  if (DECL_RTL (decl) == 0)
    {
      DECL_RTL (decl) = 0;

      /* First detect errors in declaring global registers.  */
      if (TREE_CODE (decl) != FUNCTION_DECL
	  && DECL_REGISTER (decl) && reg_number == -1)
	error_with_decl (decl,
			 "register name not specified for `%s'");
      else if (TREE_CODE (decl) != FUNCTION_DECL
	       && DECL_REGISTER (decl) && reg_number < 0)
	error_with_decl (decl,
			 "invalid register name for `%s'");
      else if ((reg_number >= 0 || reg_number == -3)
	       && (TREE_CODE (decl) == FUNCTION_DECL
		   && ! DECL_REGISTER (decl)))
	error_with_decl (decl,
			 "register name given for non-register variable `%s'");
      else if (TREE_CODE (decl) != FUNCTION_DECL
	       && DECL_REGISTER (decl)
	       && TYPE_MODE (TREE_TYPE (decl)) == BLKmode)
	error_with_decl (decl,
			 "data type of `%s' isn't suitable for a register");
      else if (TREE_CODE (decl) != FUNCTION_DECL && DECL_REGISTER (decl)
	       && ! HARD_REGNO_MODE_OK (reg_number,
					TYPE_MODE (TREE_TYPE (decl))))
	error_with_decl (decl,
			 "register number for `%s' isn't suitable for data type");
      /* Now handle properly declared static register variables.  */
      else if (TREE_CODE (decl) != FUNCTION_DECL && DECL_REGISTER (decl))
	{
	  int nregs;

	  if (DECL_INITIAL (decl) != 0 && top_level)
	    {
	      DECL_INITIAL (decl) = 0;
	      error ("global register variable has initial value");
	    }
	  if (fixed_regs[reg_number] == 0
	      && function_defined && top_level)
	    error ("global register variable follows a function definition");
	  if (TREE_THIS_VOLATILE (decl))
	    warning ("volatile register variables don't work as you might wish");

	  /* If the user specified one of the eliminables registers here,
	     e.g., FRAME_POINTER_REGNUM, we don't want to get this variable
	     confused with that register and be eliminated.  Although this
	     usage is somewhat suspect, we nevertheless use the following
	     kludge to avoid setting DECL_RTL to frame_pointer_rtx.  */

	  DECL_RTL (decl)
	    = gen_rtx (REG, DECL_MODE (decl), FIRST_PSEUDO_REGISTER);
	  REGNO (DECL_RTL (decl)) = reg_number;
	  REG_USERVAR_P (DECL_RTL (decl)) = 1;

	  if (top_level)
	    {
	      /* Make this register global, so not usable for anything
		 else.  */
	      nregs = HARD_REGNO_NREGS (reg_number, DECL_MODE (decl));
	      while (nregs > 0)
		globalize_reg (reg_number + --nregs);
	    }
	}
      /* Specifying a section attribute on a variable forces it into a
         non-.bss section, and thus it cannot be common. */
      else if (TREE_CODE (decl) == VAR_DECL
	       && DECL_SECTION_NAME (decl) != NULL_TREE
	       && DECL_INITIAL (decl) == NULL_TREE
	       && DECL_COMMON (decl))
          DECL_COMMON (decl) = 0;

      /* Now handle ordinary static variables and functions (in memory).
	 Also handle vars declared register invalidly.  */
      if (DECL_RTL (decl) == 0)
	{
	  /* Can't use just the variable's own name for a variable
	     whose scope is less than the whole file.
	     Concatenate a distinguishing number.  */
	  if (!top_level && !TREE_PUBLIC (decl) && asmspec == 0)
	    {
	      char *label;

	      ASM_FORMAT_PRIVATE_NAME (label, name, var_labelno);
	      name = obstack_copy0 (saveable_obstack, label, strlen (label));
	      var_labelno++;
	    }

	  if (name == 0)
	    abort ();

	  /* When -fprefix-function-name is used, the functions
	     names are prefixed.  Only nested function names are not
	     prefixed.  */
	  if (flag_prefix_function_name && TREE_CODE (decl) == FUNCTION_DECL)
	    {
	      char *new_name;
	      new_name = (char *) alloca (strlen (name) + CHKR_PREFIX_SIZE 
	      				  + 1);
	      strcpy (new_name, CHKR_PREFIX);
	      strcpy (new_name + CHKR_PREFIX_SIZE, name);
	      name = obstack_copy0 (saveable_obstack,
	      			   new_name, strlen (new_name));
	    }

	  DECL_RTL (decl) = gen_rtx (MEM, DECL_MODE (decl),
				     gen_rtx (SYMBOL_REF, Pmode, name));

	  /* If this variable is to be treated as volatile, show its
	     tree node has side effects.  If it has side effects, either
	     because of this test or from TREE_THIS_VOLATILE also
	     being set, show the MEM is volatile.  */
	  if (flag_volatile_global && TREE_CODE (decl) == VAR_DECL
	      && TREE_PUBLIC (decl))
	    TREE_SIDE_EFFECTS (decl) = 1;
	  if (TREE_SIDE_EFFECTS (decl))
	    MEM_VOLATILE_P (DECL_RTL (decl)) = 1;

	  if (TREE_READONLY (decl))
	    RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
	  MEM_IN_STRUCT_P (DECL_RTL (decl))
	    = AGGREGATE_TYPE_P (TREE_TYPE (decl));

	  /* Optionally set flags or add text to the name to record information
	     such as that it is a function name.
	     If the name is changed, the macro ASM_OUTPUT_LABELREF
	     will have to know how to strip this information.  */
#ifdef ENCODE_SECTION_INFO
	  ENCODE_SECTION_INFO (decl);
#endif
	}
    }
  /* If the old RTL had the wrong mode, fix the mode.  */
  else if (GET_MODE (DECL_RTL (decl)) != DECL_MODE (decl))
    {
      rtx rtl = DECL_RTL (decl);
      PUT_MODE (rtl, DECL_MODE (decl));
    }
}

/* Make the rtl for variable VAR be volatile.
   Use this only for static variables.  */

void
make_var_volatile (var)
     tree var;
{
  if (GET_CODE (DECL_RTL (var)) != MEM)
    abort ();

  MEM_VOLATILE_P (DECL_RTL (var)) = 1;
}

/* Output alignment directive to align for constant expression EXP.  */

void
assemble_constant_align (exp)
     tree exp;
{
  int align;

  /* Align the location counter as required by EXP's data type.  */
  align = TYPE_ALIGN (TREE_TYPE (exp));
#ifdef CONSTANT_ALIGNMENT
  align = CONSTANT_ALIGNMENT (exp, align);
#endif

  if (align > BITS_PER_UNIT)
    ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (align / BITS_PER_UNIT));
}

/* Output a string of literal assembler code
   for an `asm' keyword used between functions.  */

void
assemble_asm (string)
     tree string;
{
  if (output_bytecode)
    {
      error ("asm statements not allowed in interpreter");
      return;
    }

  app_enable ();

  if (TREE_CODE (string) == ADDR_EXPR)
    string = TREE_OPERAND (string, 0);

  fprintf (asm_out_file, "\t%s\n", TREE_STRING_POINTER (string));
}

#if 0 /* This should no longer be needed, because
	 flag_gnu_linker should be 0 on these systems,
	 which should prevent any output
	 if ASM_OUTPUT_CONSTRUCTOR and ASM_OUTPUT_DESTRUCTOR are absent.  */
#if !(defined(DBX_DEBUGGING_INFO) && !defined(FASCIST_ASSEMBLER))
#ifndef ASM_OUTPUT_CONSTRUCTOR
#define ASM_OUTPUT_CONSTRUCTOR(file, name)
#endif
#ifndef ASM_OUTPUT_DESTRUCTOR
#define ASM_OUTPUT_DESTRUCTOR(file, name)
#endif
#endif
#endif /* 0 */

/* Record an element in the table of global destructors.
   How this is done depends on what sort of assembler and linker
   are in use.

   NAME should be the name of a global function to be called
   at exit time.  This name is output using assemble_name.  */

void
assemble_destructor (name)
     char *name;
{
#ifdef ASM_OUTPUT_DESTRUCTOR
  ASM_OUTPUT_DESTRUCTOR (asm_out_file, name);
#else
  if (flag_gnu_linker)
    {
      /* Now tell GNU LD that this is part of the static destructor set.  */
      /* This code works for any machine provided you use GNU as/ld.  */
      fprintf (asm_out_file, "%s \"___DTOR_LIST__\",22,0,0,", ASM_STABS_OP);
      assemble_name (asm_out_file, name);
      fputc ('\n', asm_out_file);
    }
#endif
}

/* Likewise for global constructors.  */

void
assemble_constructor (name)
     char *name;
{
#ifdef ASM_OUTPUT_CONSTRUCTOR
  ASM_OUTPUT_CONSTRUCTOR (asm_out_file, name);
#else
  if (flag_gnu_linker)