gcc/config/vxworks.c

   1 /* Common VxWorks target definitions for GNU compiler.
   2    Copyright (C) 2007-2017 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 "tree.h"
  26 #include "stringpool.h"
  27 #include "diagnostic-core.h"
  28 #include "output.h"
  29 #include "fold-const.h"
  30
  31 /* Like default_named_section_asm_out_constructor, except that even
  32    constructors with DEFAULT_INIT_PRIORITY must go in a numbered
  33    section on VxWorks.  The VxWorks runtime uses a clever trick to get
  34    the sentinel entry (-1) inserted at the beginning of the .ctors
  35    segment.  This trick will not work if we ever generate any entries
  36    in plain .ctors sections; we must always use .ctors.PRIORITY.  */
  37
  38 void
  39 vxworks_asm_out_constructor (rtx symbol, int priority)
  40 {
  41   section *sec;
  42
  43   sec = get_cdtor_priority_section (priority,
  44                                     /*constructor_p=*/true);
  45   assemble_addr_to_section (symbol, sec);
  46 }
  47
  48 /* See comment for vxworks_asm_out_constructor.  */
  49
  50 void
  51 vxworks_asm_out_destructor (rtx symbol, int priority)
  52 {
  53   section *sec;
  54
  55   sec = get_cdtor_priority_section (priority,
  56                                     /*constructor_p=*/false);
  57   assemble_addr_to_section (symbol, sec);
  58 }
  59
  60 /* Return the list of FIELD_DECLs that make up an emulated TLS
  61    variable's control object.  TYPE is the structure these are fields
  62    of and *NAME will be filled in with the structure tag that should
  63    be used.  */
  64
  65 static tree
  66 vxworks_emutls_var_fields (tree type, tree *name)
  67 {
  68   tree field, next_field;
  69
  70   *name = get_identifier ("__tls_var");
  71
  72   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  73                       get_identifier ("size"), unsigned_type_node);
  74   DECL_CONTEXT (field) = type;
  75   next_field = field;
  76
  77   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  78                       get_identifier ("module_id"), unsigned_type_node);
  79   DECL_CONTEXT (field) = type;
  80   DECL_CHAIN (field) = next_field;
  81   next_field = field;
  82
  83   /* The offset field is declared as an unsigned int with pointer mode.  */
  84   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  85                       get_identifier ("offset"), long_unsigned_type_node);
  86
  87   DECL_CONTEXT (field) = type;
  88   DECL_CHAIN (field) = next_field;
  89
  90   return field;
  91 }
  92
  93 /* Return the CONSTRUCTOR to initialize an emulated TLS control
  94    object.  VAR is the control object.  DECL is the TLS object itself
  95    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
  96    that object.  */
  97
  98 static tree
  99 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
 100 {
 101   vec<constructor_elt, va_gc> *v;
 102   vec_alloc (v, 3);
 103
 104   tree type = TREE_TYPE (var);
 105   tree field = TYPE_FIELDS (type);
 106
 107   constructor_elt elt = {field, fold_convert (TREE_TYPE (field), tmpl_addr)};
 108   v->quick_push (elt);
 109
 110   field = DECL_CHAIN (field);
 111   elt.index = field;
 112   elt.value = build_int_cst (TREE_TYPE (field), 0);
 113   v->quick_push (elt);
 114
 115   field = DECL_CHAIN (field);
 116   elt.index = field;
 117   elt.value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 118   v->quick_push (elt);
 119
 120   return build_constructor (type, v);
 121 }
 122
 123 /* Do VxWorks-specific parts of TARGET_OPTION_OVERRIDE.  */
 124
 125 void
 126 vxworks_override_options (void)
 127 {
 128   /* Setup the tls emulation bits if the OS misses proper
 129      tls support.  */
 130   targetm.have_tls = VXWORKS_HAVE_TLS;
 131
 132   if (!VXWORKS_HAVE_TLS)
 133     {
 134       targetm.emutls.get_address = "__builtin___tls_lookup";
 135       targetm.emutls.register_common = NULL;
 136       targetm.emutls.var_section = ".tls_vars";
 137       targetm.emutls.tmpl_section = ".tls_data";
 138       targetm.emutls.var_prefix = "__tls__";
 139       targetm.emutls.tmpl_prefix = "";
 140       targetm.emutls.var_fields = vxworks_emutls_var_fields;
 141       targetm.emutls.var_init = vxworks_emutls_var_init;
 142       targetm.emutls.var_align_fixed = true;
 143       targetm.emutls.debug_form_tls_address = true;
 144     }
 145
 146   /* We can use .ctors/.dtors sections only in RTP mode.  */
 147   targetm.have_ctors_dtors = TARGET_VXWORKS_RTP;
 148
 149   /* PIC is only supported for RTPs.  */
 150   if (flag_pic && !TARGET_VXWORKS_RTP)
 151     error ("PIC is only supported for RTPs");
 152
 153   /* Default to strict dwarf-2 to prevent potential difficulties observed with
 154      non-gdb debuggers on extensions > 2.  */
 155   if (!global_options_set.x_dwarf_strict)
 156     dwarf_strict = 1;
 157
 158   if (!global_options_set.x_dwarf_version)
 159     dwarf_version = 2;
 160 }