gcc/targhooks.c

   1 /* Default target hook functions.
   2    Copyright (C) 2003, 2004 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to the Free
  18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 /* The migration of target macros to target hooks works as follows:
  22
  23    1. Create a target hook that uses the existing target macros to
  24       implement the same functionality.
  25
  26    2. Convert all the MI files to use the hook instead of the macro.
  27
  28    3. Repeat for a majority of the remaining target macros.  This will
  29       take some time.
  30
  31    4. Tell target maintainers to start migrating.
  32
  33    5. Eventually convert the backends to override the hook instead of
  34       defining the macros.  This will take some time too.
  35
  36    6. TBD when, poison the macros.  Unmigrated targets will break at
  37       this point.
  38
  39    Note that we expect steps 1-3 to be done by the people that
  40    understand what the MI does with each macro, and step 5 to be done
  41    by the target maintainers for their respective targets.
  42
  43    Note that steps 1 and 2 don't have to be done together, but no
  44    target can override the new hook until step 2 is complete for it.
  45
  46    Once the macros are poisoned, we will revert to the old migration
  47    rules - migrate the macro, callers, and targets all at once.  This
  48    comment can thus be removed at that point.  */
  49
  50 #include "config.h"
  51 #include "system.h"
  52 #include "coretypes.h"
  53 #include "tm.h"
  54 #include "machmode.h"
  55 #include "rtl.h"
  56 #include "tree.h"
  57 #include "expr.h"
  58 #include "output.h"
  59 #include "toplev.h"
  60 #include "function.h"
  61 #include "target.h"
  62 #include "tm_p.h"
  63 #include "target-def.h"
  64
  65 void
  66 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
  67 {
  68 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  69   ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
  70 #endif
  71 }
  72
  73 enum machine_mode
  74 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
  75 {
  76   if (m1 == m2)
  77     return m1;
  78   return VOIDmode;
  79 }
  80
  81 bool
  82 default_return_in_memory (tree type,
  83                           tree fntype ATTRIBUTE_UNUSED)
  84 {
  85 #ifndef RETURN_IN_MEMORY
  86   return (TYPE_MODE (type) == BLKmode);
  87 #else
  88   return RETURN_IN_MEMORY (type);
  89 #endif
  90 }
  91
  92 rtx
  93 default_expand_builtin_saveregs (void)
  94 {
  95   error ("__builtin_saveregs not supported by this target");
  96   return const0_rtx;
  97 }
  98
  99 void
 100 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 101                                 enum machine_mode mode ATTRIBUTE_UNUSED,
 102                                 tree type ATTRIBUTE_UNUSED,
 103                                 int *pretend_arg_size ATTRIBUTE_UNUSED,
 104                                 int second_time ATTRIBUTE_UNUSED)
 105 {
 106 }
 107
 108 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE.  */
 109
 110 rtx
 111 default_builtin_setjmp_frame_value (void)
 112 {
 113   return virtual_stack_vars_rtx;
 114 }
 115
 116 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false.  */
 117
 118 bool
 119 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 120 {
 121   return false;
 122 }
 123
 124 bool
 125 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 126 {
 127   return (targetm.calls.setup_incoming_varargs
 128           != default_setup_incoming_varargs);
 129 }
 130
 131 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true.  */
 132
 133 bool
 134 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
 135 {
 136   return true;
 137 }
 138
 139
 140 /* The generic C++ ABI specifies this is a 64-bit value.  */
 141 tree
 142 default_cxx_guard_type (void)
 143 {
 144   return long_long_integer_type_node;
 145 }