8sa1-gcc/gcc/target.h

/* Data structure definitions for a generic GCC target.
   Copyright (C) 2001 Free Software Foundation, Inc.

This program 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.

This program 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 this program; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 In other words, you are welcome to use, share and improve this program.
 You are forbidden to forbid anyone else to use, share and improve
 what you give them.   Help stamp out software-hoarding!  */

/* This file contains a data structure that describes a GCC target.
   At present it is incomplete, but in future it should grow to
   contain most or all target machine and target O/S specific
   information.

   This structure has its initializer declared in target-def.h in the
   form of large macro TARGET_INITIALIZER that expands to many smaller
   macros.

   The smaller macros each initialize one component of the structure,
   and each has a default.  Each target should have a file that
   includes target.h and target-def.h, and overrides any inappropriate
   defaults by undefining the relevant macro and defining a suitable
   replacement.  That file should then contain the definition of
   "targetm" like so:

   struct gcc_target targetm = TARGET_INITIALIZER;

   Doing things this way allows us to bring together everything that
   defines a GCC target.  By supplying a default that is appropriate
   to most targets, we can easily add new items without needing to
   edit dozens of target configuration files.  It should also allow us
   to gradually reduce the amount of conditional compilation that is
   scattered throughout GCC.  */

/* Forward declaration for the benefit of prototypes.  */
struct rtx_def;

struct gcc_target
{
  /* Functions that output assembler for the target.  */
  struct asm_out
  {
    /* Opening and closing parentheses for asm expression grouping.  */
    const char *open_paren, *close_paren;

    /* Output the assembler code for entry to a function.  */
    void (* function_prologue) PARAMS ((FILE *, HOST_WIDE_INT));

    /* Output the assembler code for end of prologue.  */
    void (* function_end_prologue) PARAMS ((FILE *));

    /* Output the assembler code for start of epilogue.  */
    void (* function_begin_epilogue) PARAMS ((FILE *));

    /* Output the assembler code for function exit.  */
    void (* function_epilogue) PARAMS ((FILE *, HOST_WIDE_INT));
  } asm_out;

  /* Given two decls, merge their attributes and return the result.  */
  tree (* merge_decl_attributes) PARAMS ((tree, tree));

  /* Given two types, merge their attributes and return the result.  */
  tree (* merge_type_attributes) PARAMS ((tree, tree));

  /* Return nonzero if IDENTIFIER with arguments ARGS is a valid machine
     specific attribute for DECL.  The attributes in ATTRIBUTES have
     previously been assigned to DECL.  */
  int (* valid_decl_attribute) PARAMS ((tree decl, tree attributes,
					tree identifier, tree args));

  /* Return nonzero if IDENTIFIER with arguments ARGS is a valid machine
     specific attribute for TYPE.  The attributes in ATTRIBUTES have
     previously been assigned to TYPE.  */
  int (* valid_type_attribute) PARAMS ((tree type, tree attributes,
					tree identifier, tree args));

  /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
     one if they are compatible and two if they are nearly compatible
     (which causes a warning to be generated).  */
  int (* comp_type_attributes) PARAMS ((tree type1, tree type2));

  /* Assign default attributes to the newly defined TYPE.  */
  void (* set_default_type_attributes) PARAMS ((tree type));

  /* Insert attributes on the newly created DECL.  */
  void (* insert_attributes) PARAMS ((tree decl, tree *attributes));

  /* Set up target-specific built-in functions.  */
  void (* init_builtins) PARAMS ((void));

  /* Expand a target-specific builtin.  */
  struct rtx_def * (* expand_builtin) PARAMS ((tree exp,
					       struct rtx_def *target,
					       struct rtx_def *subtarget,
					       enum machine_mode mode,
					       int ignore));
};

extern struct gcc_target targetm;