1  /* Common macros for target hook definitions.
       2     Copyright (C) 2001-2023 Free Software Foundation, Inc.
       3  
       4     This program is free software; you can redistribute it and/or modify it
       5     under the terms of the GNU General Public License as published by the
       6     Free Software Foundation; either version 3, or (at your option) any
       7     later version.
       8  
       9     This program is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program; see the file COPYING3.  If not see
      16     <http://www.gnu.org/licenses/>.  */
      17  
      18  /* The following macros should be provided by the including file:
      19  
      20     DEFHOOK(NAME, DOC, TYPE, PARAMS, INIT): Define a function-valued hook.
      21     DEFHOOKPOD(NAME, DOC, TYPE, INIT): Define a piece-of-data 'hook'.  */
      22  
      23  /* Defaults for optional macros:
      24     DEFHOOKPODX(NAME, TYPE, INIT): Like DEFHOOKPOD, but share documentation
      25     with the previous 'hook'.  */
      26  #ifndef DEFHOOKPODX
      27  #define DEFHOOKPODX(NAME, TYPE, INIT) DEFHOOKPOD (NAME, 0, TYPE, INIT)
      28  #endif
      29     
      30  /* HOOKSTRUCT(FRAGMENT): Declarator fragments to encapsulate all the
      31     members into a struct gcc_target, which in turn contains several
      32     sub-structs.  */
      33  #ifndef HOOKSTRUCT
      34  #define HOOKSTRUCT(FRAGMENT)
      35  #endif
      36  /* HOOK_VECTOR: Start a struct declaration, which then gets its own initializer.
      37     HOOK_VECTOR_END: Close a struct declaration, providing a member declarator
      38                      name for nested use.  */
      39  #ifndef HOOK_VECTOR_1
      40  #define HOOK_VECTOR_1(NAME, FRAGMENT) HOOKSTRUCT (FRAGMENT)
      41  #endif
      42  #define HOOK_VECTOR(INIT_NAME, SNAME) HOOK_VECTOR_1 (INIT_NAME, struct SNAME {)
      43  #define HOOK_VECTOR_END(DECL_NAME) HOOK_VECTOR_1(,} DECL_NAME ;)
      44  
      45  /* FIXME: For pre-existing hooks, we can't place the documentation in the
      46     documentation field here till we get permission from the FSF to include
      47     it in GPLed software - the target hook documentation is so far only
      48     available under the GFDL.  */
      49  
      50  /* A hook should generally be documented by a string in the DOC parameter,
      51     which should contain texinfo markup.  If the documentation is only available
      52     under the GPL, but not under the GFDL, put it in a comment above the hook
      53     definition.  If the function declaration is available both under GPL and
      54     GFDL, but the documentation is only available under the GFDL, put the
      55     documentaton in tm.texi.in, heading with @hook <hookname> and closing
      56     the paragraph with @end deftypefn / deftypevr as appropriate, and marking
      57     the next autogenerated hook with @hook <hookname>.
      58     In both these cases, leave the DOC string empty, i.e. "".
      59     Sometimes, for some historic reason the function declaration 
      60     has to be documented differently
      61     than what it is.  In that case, use DEFHOOK_UNDOC to suppress auto-generation
      62     of documentation.  DEFHOOK_UNDOC takes a DOC string which it ignores, so
      63     you can put GPLed documentation string there if you have hopes that you
      64     can clear the declaration & documentation for GFDL distribution later,
      65     in which case you can then simply change the DEFHOOK_UNDOC to DEFHOOK
      66     to turn on the autogeneration of the documentation.
      67  
      68      A documentation string of "*" means not to emit any documentation at all,
      69     and is mainly used internally for DEFHOOK_UNDOC.  It should generally not
      70     be used otherwise, but it has its use for exceptional cases where automatic
      71     documentation is not wanted, and the real documentation is elsewere, like
      72     for TARGET_ASM_{,UN}ALIGNED_INT_OP, which are hooks only for implementation
      73     purposes; they refer to structs, the components of which are documented as
      74     separate hooks TARGET_ASM_{,UN}ALIGNED_[HSDT]I_OP.
      75     A DOC string of 0 is for internal use of DEFHOOKPODX and special table
      76     entries only.  */
      77  
      78  /* Empty macro arguments are undefined in C90, so use an empty macro
      79     to close top-level hook structures.  */
      80  #define C90_EMPTY_HACK