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 "target.h"
  25 #include "diagnostic-core.h"
  26 #include "output.h"
  27 #include "tm.h"
  28 #include "alias.h"
  29 #include "symtab.h"
  30 #include "tree.h"
  31 #include "fold-const.h"
  32 #include "stringpool.h"
  33
  34 /* Like default_named_section_asm_out_constructor, except that even
  35    constructors with DEFAULT_INIT_PRIORITY must go in a numbered
  36    section on VxWorks.  The VxWorks runtime uses a clever trick to get
  37    the sentinel entry (-1) inserted at the beginning of the .ctors
  38    segment.  This trick will not work if we ever generate any entries
  39    in plain .ctors sections; we must always use .ctors.PRIORITY.  */
  40
  41 void
  42 vxworks_asm_out_constructor (rtx symbol, int priority)
  43 {
  44   section *sec;
  45
  46   sec = get_cdtor_priority_section (priority,
  47                                     /*constructor_p=*/true);
  48   assemble_addr_to_section (symbol, sec);
  49 }
  50
  51 /* See comment for vxworks_asm_out_constructor.  */
  52
  53 void
  54 vxworks_asm_out_destructor (rtx symbol, int priority)
  55 {
  56   section *sec;
  57
  58   sec = get_cdtor_priority_section (priority,
  59                                     /*constructor_p=*/false);
  60   assemble_addr_to_section (symbol, sec);
  61 }
  62
  63 /* Return the list of FIELD_DECLs that make up an emulated TLS
  64    variable's control object.  TYPE is the structure these are fields
  65    of and *NAME will be filled in with the structure tag that should
  66    be used.  */
  67
  68 static tree
  69 vxworks_emutls_var_fields (tree type, tree *name)
  70 {
  71   tree field, next_field;
  72
  73   *name = get_identifier ("__tls_var");
  74
  75   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  76                       get_identifier ("size"), unsigned_type_node);
  77   DECL_CONTEXT (field) = type;
  78   next_field = field;
  79
  80   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  81                       get_identifier ("module_id"), unsigned_type_node);
  82   DECL_CONTEXT (field) = type;
  83   DECL_CHAIN (field) = next_field;
  84   next_field = field;
  85
  86   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  87                       get_identifier ("offset"), unsigned_type_node);
  88   DECL_CONTEXT (field) = type;
  89   DECL_CHAIN (field) = next_field;
  90
  91   return field;
  92 }
  93
  94 /* Return the CONSTRUCTOR to initialize an emulated TLS control
  95    object.  VAR is the control object.  DECL is the TLS object itself
  96    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
  97    that object.  */
  98
  99 static tree
 100 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
 101 {
 102   vec<constructor_elt, va_gc> *v;
 103   vec_alloc (v, 3);
 104
 105   tree type = TREE_TYPE (var);
 106   tree field = TYPE_FIELDS (type);
 107
 108   constructor_elt elt = {field, fold_convert (TREE_TYPE (field), tmpl_addr)};
 109   v->quick_push (elt);
 110
 111   field = DECL_CHAIN (field);
 112   elt.index = field;
 113   elt.value = build_int_cst (TREE_TYPE (field), 0);
 114   v->quick_push (elt);
 115
 116   field = DECL_CHAIN (field);
 117   elt.index = field;
 118   elt.value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 119   v->quick_push (elt);
 120
 121   return build_constructor (type, v);
 122 }
 123
 124 /* Do VxWorks-specific parts of TARGET_OPTION_OVERRIDE.  */
 125
 126 void
 127 vxworks_override_options (void)
 128 {
 129   /* We don't support __thread via target hooks.  */
 130   targetm.have_tls = false;
 131
 132   targetm.emutls.get_address = "__builtin___tls_lookup";
 133   targetm.emutls.register_common = NULL;
 134   targetm.emutls.var_section = ".tls_vars";
 135   targetm.emutls.tmpl_section = ".tls_data";
 136   targetm.emutls.var_prefix = "__tls__";
 137   targetm.emutls.tmpl_prefix = "";
 138   targetm.emutls.var_fields = vxworks_emutls_var_fields;
 139   targetm.emutls.var_init = vxworks_emutls_var_init;
 140   targetm.emutls.var_align_fixed = true;
 141   targetm.emutls.debug_form_tls_address = true;
 142
 143   /* We can use .ctors/.dtors sections only in RTP mode.  */
 144   targetm.have_ctors_dtors = TARGET_VXWORKS_RTP;
 145
 146   /* PIC is only supported for RTPs.  */
 147   if (flag_pic && !TARGET_VXWORKS_RTP)
 148     error ("PIC is only supported for RTPs");
 149
 150   /* Default to strict dwarf-2 to prevent potential difficulties observed with
 151      non-gdb debuggers on extensions > 2.  */
 152   if (!global_options_set.x_dwarf_strict)
 153     dwarf_strict = 1;
 154
 155   if (!global_options_set.x_dwarf_version)
 156     dwarf_version = 2;
 157 }