gcc/config/vxworks.c

   1 /* Common VxWorks target definitions for GNU compiler.
   2    Copyright (C) 2007-2015 Free Software Foundation, Inc.
   3    Contributed by CodeSourcery, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "vec.h"
  25 #include "target.h"
  26 #include "diagnostic-core.h"
  27 #include "output.h"
  28 #include "tm.h"
  29 #include "hash-set.h"
  30 #include "machmode.h"
  31 #include "double-int.h"
  32 #include "input.h"
  33 #include "alias.h"
  34 #include "symtab.h"
  35 #include "wide-int.h"
  36 #include "inchash.h"
  37 #include "tree.h"
  38 #include "fold-const.h"
  39 #include "stringpool.h"
  40
  41 /* Like default_named_section_asm_out_constructor, except that even
  42    constructors with DEFAULT_INIT_PRIORITY must go in a numbered
  43    section on VxWorks.  The VxWorks runtime uses a clever trick to get
  44    the sentinel entry (-1) inserted at the beginning of the .ctors
  45    segment.  This trick will not work if we ever generate any entries
  46    in plain .ctors sections; we must always use .ctors.PRIORITY.  */
  47
  48 void
  49 vxworks_asm_out_constructor (rtx symbol, int priority)
  50 {
  51   section *sec;
  52
  53   sec = get_cdtor_priority_section (priority,
  54                                     /*constructor_p=*/true);
  55   assemble_addr_to_section (symbol, sec);
  56 }
  57
  58 /* See comment for vxworks_asm_out_constructor.  */
  59
  60 void
  61 vxworks_asm_out_destructor (rtx symbol, int priority)
  62 {
  63   section *sec;
  64
  65   sec = get_cdtor_priority_section (priority,
  66                                     /*constructor_p=*/false);
  67   assemble_addr_to_section (symbol, sec);
  68 }
  69
  70 /* Return the list of FIELD_DECLs that make up an emulated TLS
  71    variable's control object.  TYPE is the structure these are fields
  72    of and *NAME will be filled in with the structure tag that should
  73    be used.  */
  74
  75 static tree
  76 vxworks_emutls_var_fields (tree type, tree *name)
  77 {
  78   tree field, next_field;
  79
  80   *name = get_identifier ("__tls_var");
  81
  82   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  83                       get_identifier ("size"), unsigned_type_node);
  84   DECL_CONTEXT (field) = type;
  85   next_field = field;
  86
  87   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  88                       get_identifier ("module_id"), unsigned_type_node);
  89   DECL_CONTEXT (field) = type;
  90   DECL_CHAIN (field) = next_field;
  91   next_field = field;
  92
  93   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  94                       get_identifier ("offset"), unsigned_type_node);
  95   DECL_CONTEXT (field) = type;
  96   DECL_CHAIN (field) = next_field;
  97
  98   return field;
  99 }
 100
 101 /* Return the CONSTRUCTOR to initialize an emulated TLS control
 102    object.  VAR is the control object.  DECL is the TLS object itself
 103    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
 104    that object.  */
 105
 106 static tree
 107 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
 108 {
 109   vec<constructor_elt, va_gc> *v;
 110   vec_alloc (v, 3);
 111
 112   tree type = TREE_TYPE (var);
 113   tree field = TYPE_FIELDS (type);
 114
 115   constructor_elt elt = {field, fold_convert (TREE_TYPE (field), tmpl_addr)};
 116   v->quick_push (elt);
 117
 118   field = DECL_CHAIN (field);
 119   elt.index = field;
 120   elt.value = build_int_cst (TREE_TYPE (field), 0);
 121   v->quick_push (elt);
 122
 123   field = DECL_CHAIN (field);
 124   elt.index = field;
 125   elt.value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 126   v->quick_push (elt);
 127
 128   return build_constructor (type, v);
 129 }
 130
 131 /* Do VxWorks-specific parts of TARGET_OPTION_OVERRIDE.  */
 132
 133 void
 134 vxworks_override_options (void)
 135 {
 136   /* We don't support __thread via target hooks.  */
 137   targetm.have_tls = false;
 138
 139   targetm.emutls.get_address = "__builtin___tls_lookup";
 140   targetm.emutls.register_common = NULL;
 141   targetm.emutls.var_section = ".tls_vars";
 142   targetm.emutls.tmpl_section = ".tls_data";
 143   targetm.emutls.var_prefix = "__tls__";
 144   targetm.emutls.tmpl_prefix = "";
 145   targetm.emutls.var_fields = vxworks_emutls_var_fields;
 146   targetm.emutls.var_init = vxworks_emutls_var_init;
 147   targetm.emutls.var_align_fixed = true;
 148   targetm.emutls.debug_form_tls_address = true;
 149
 150   /* We can use .ctors/.dtors sections only in RTP mode.  */
 151   targetm.have_ctors_dtors = TARGET_VXWORKS_RTP;
 152
 153   /* PIC is only supported for RTPs.  */
 154   if (flag_pic && !TARGET_VXWORKS_RTP)
 155     error ("PIC is only supported for RTPs");
 156
 157   /* Default to strict dwarf-2 to prevent potential difficulties observed with
 158      non-gdb debuggers on extensions > 2.  */
 159   if (!global_options_set.x_dwarf_strict)
 160     dwarf_strict = 1;
 161
 162   if (!global_options_set.x_dwarf_version)
 163     dwarf_version = 2;
 164 }