gcc/config/vxworks.c

   1 /* Common VxWorks target definitions for GNU compiler.
   2    Copyright (C) 2007-2013 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 "target.h"
  25 #include "diagnostic-core.h"
  26 #include "output.h"
  27 #include "tm.h"
  28 #include "tree.h"
  29
  30 /* Like default_named_section_asm_out_constructor, except that even
  31    constructors with DEFAULT_INIT_PRIORITY must go in a numbered
  32    section on VxWorks.  The VxWorks runtime uses a clever trick to get
  33    the sentinel entry (-1) inserted at the beginning of the .ctors
  34    segment.  This trick will not work if we ever generate any entries
  35    in plain .ctors sections; we must always use .ctors.PRIORITY.  */
  36
  37 void
  38 vxworks_asm_out_constructor (rtx symbol, int priority)
  39 {
  40   section *sec;
  41
  42   sec = get_cdtor_priority_section (priority,
  43                                     /*constructor_p=*/true);
  44   assemble_addr_to_section (symbol, sec);
  45 }
  46
  47 /* See comment for vxworks_asm_out_constructor.  */
  48
  49 void
  50 vxworks_asm_out_destructor (rtx symbol, int priority)
  51 {
  52   section *sec;
  53
  54   sec = get_cdtor_priority_section (priority,
  55                                     /*constructor_p=*/false);
  56   assemble_addr_to_section (symbol, sec);
  57 }
  58
  59 /* Return the list of FIELD_DECLs that make up an emulated TLS
  60    variable's control object.  TYPE is the structure these are fields
  61    of and *NAME will be filled in with the structure tag that should
  62    be used.  */
  63
  64 static tree
  65 vxworks_emutls_var_fields (tree type, tree *name)
  66 {
  67   tree field, next_field;
  68
  69   *name = get_identifier ("__tls_var");
  70
  71   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  72                       get_identifier ("size"), unsigned_type_node);
  73   DECL_CONTEXT (field) = type;
  74   next_field = field;
  75
  76   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  77                       get_identifier ("module_id"), unsigned_type_node);
  78   DECL_CONTEXT (field) = type;
  79   DECL_CHAIN (field) = next_field;
  80   next_field = field;
  81
  82   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  83                       get_identifier ("offset"), unsigned_type_node);
  84   DECL_CONTEXT (field) = type;
  85   DECL_CHAIN (field) = next_field;
  86
  87   return field;
  88 }
  89
  90 /* Return the CONSTRUCTOR to initialize an emulated TLS control
  91    object.  VAR is the control object.  DECL is the TLS object itself
  92    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
  93    that object.  */
  94
  95 static tree
  96 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
  97 {
  98   vec<constructor_elt, va_gc> *v;
  99   vec_alloc (v, 3);
 100
 101   tree type = TREE_TYPE (var);
 102   tree field = TYPE_FIELDS (type);
 103
 104   constructor_elt elt = {field, fold_convert (TREE_TYPE (field), tmpl_addr)};
 105   v->quick_push (elt);
 106
 107   field = DECL_CHAIN (field);
 108   elt.index = field;
 109   elt.value = build_int_cst (TREE_TYPE (field), 0);
 110   v->quick_push (elt);
 111
 112   field = DECL_CHAIN (field);
 113   elt.index = field;
 114   elt.value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 115   v->quick_push (elt);
 116
 117   return build_constructor (type, v);
 118 }
 119
 120 /* Do VxWorks-specific parts of TARGET_OPTION_OVERRIDE.  */
 121
 122 void
 123 vxworks_override_options (void)
 124 {
 125   /* We don't support __thread via target hooks.  */
 126   targetm.have_tls = false;
 127
 128   targetm.emutls.get_address = "__builtin___tls_lookup";
 129   targetm.emutls.register_common = NULL;
 130   targetm.emutls.var_section = ".tls_vars";
 131   targetm.emutls.tmpl_section = ".tls_data";
 132   targetm.emutls.var_prefix = "__tls__";
 133   targetm.emutls.tmpl_prefix = "";
 134   targetm.emutls.var_fields = vxworks_emutls_var_fields;
 135   targetm.emutls.var_init = vxworks_emutls_var_init;
 136   targetm.emutls.var_align_fixed = true;
 137   targetm.emutls.debug_form_tls_address = true;
 138
 139   /* We can use .ctors/.dtors sections only in RTP mode.  */
 140   targetm.have_ctors_dtors = TARGET_VXWORKS_RTP;
 141
 142   /* PIC is only supported for RTPs.  */
 143   if (flag_pic && !TARGET_VXWORKS_RTP)
 144     error ("PIC is only supported for RTPs");
 145
 146   /* Default to strict dwarf-2 to prevent potential difficulties observed with
 147      non-gdb debuggers on extensions > 2.  */
 148   if (!global_options_set.x_dwarf_strict)
 149     dwarf_strict = 1;
 150
 151   if (!global_options_set.x_dwarf_version)
 152     dwarf_version = 2;
 153 }