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