gcc/go/go-backend.c

   1 /* go-backend.c -- Go frontend interface to gcc backend.
   2    Copyright (C) 2010, 2011 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 3, 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 COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "rtl.h"
  25 #include "tree.h"
  26 #include "tm_p.h"
  27 #include "output.h"
  28 #include "target.h"
  29 #include "common/common-target.h"
  30
  31 #include "go-c.h"
  32
  33 /* This file holds all the cases where the Go frontend needs
  34    information from gcc's backend.  */
  35
  36 /* Return the alignment in bytes of a value of type T.  */
  37
  38 unsigned int
  39 go_type_alignment (tree t)
  40 {
  41   return TYPE_ALIGN_UNIT (t);
  42 }
  43
  44 /* Return the alignment in bytes of a struct field of type T.  */
  45
  46 unsigned int
  47 go_field_alignment (tree t)
  48 {
  49   unsigned int v;
  50
  51   v = TYPE_ALIGN (t);
  52
  53 #ifdef BIGGEST_FIELD_ALIGNMENT
  54   if (v > BIGGEST_FIELD_ALIGNMENT)
  55     v = BIGGEST_FIELD_ALIGNMENT;
  56 #endif
  57
  58 #ifdef ADJUST_FIELD_ALIGN
  59   {
  60     tree field ATTRIBUTE_UNUSED;
  61     field = build_decl (UNKNOWN_LOCATION, FIELD_DECL, NULL, t);
  62     v = ADJUST_FIELD_ALIGN (field, v);
  63   }
  64 #endif
  65
  66   return v / BITS_PER_UNIT;
  67 }
  68
  69 /* Return the size and alignment of a trampoline.  */
  70
  71 void
  72 go_trampoline_info (unsigned int *size, unsigned int *alignment)
  73 {
  74   *size = TRAMPOLINE_SIZE;
  75   *alignment = TRAMPOLINE_ALIGNMENT;
  76 }
  77
  78 /* This is called by the Go frontend proper if the unsafe package was
  79    imported.  When that happens we can not do type-based alias
  80    analysis.  */
  81
  82 void
  83 go_imported_unsafe (void)
  84 {
  85   flag_strict_aliasing = false;
  86
  87   /* This is a real hack.  init_varasm_once has already grabbed an
  88      alias set, which we don't want when we aren't doing strict
  89      aliasing.  We reinitialize to make it do it again.  This should
  90      be OK in practice since we haven't really done anything yet.  */
  91   init_varasm_once ();
  92
  93   /* Let the backend know that the options have changed.  */
  94   targetm.override_options_after_change ();
  95 }
  96
  97 /* This is called by the Go frontend proper to add data to the
  98    .go_export section.  */
  99
 100 void
 101 go_write_export_data (const char *bytes, unsigned int size)
 102 {
 103   static section* sec;
 104
 105   if (sec == NULL)
 106     {
 107       gcc_assert (targetm_common.have_named_sections);
 108       sec = get_section (".go_export", SECTION_DEBUG, NULL);
 109     }
 110
 111   switch_to_section (sec);
 112   assemble_string (bytes, size);
 113 }