gcc/config/vxworks.c

   1 /* Common VxWorks target definitions for GNU compiler.
   2    Copyright (C) 2007
   3    Free Software Foundation, Inc.
   4    Contributed by CodeSourcery, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "target.h"
  26 #include "toplev.h"
  27 #include "output.h"
  28 #include "tm.h"
  29 #include "tree.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 (FIELD_DECL, get_identifier ("size"),
  73                       unsigned_type_node);
  74   DECL_CONTEXT (field) = type;
  75   next_field = field;
  76
  77   field = build_decl (FIELD_DECL, get_identifier ("module_id"),
  78                       unsigned_type_node);
  79   DECL_CONTEXT (field) = type;
  80   TREE_CHAIN (field) = next_field;
  81   next_field = field;
  82
  83   field = build_decl (FIELD_DECL, get_identifier ("offset"),
  84                       unsigned_type_node);
  85   DECL_CONTEXT (field) = type;
  86   TREE_CHAIN (field) = next_field;
  87
  88   return field;
  89 }
  90
  91 /* Return the CONSTRUCTOR to initialize an emulated TLS control
  92    object.  VAR is the control object.  DECL is the TLS object itself
  93    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
  94    that object.  */
  95
  96 static tree
  97 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
  98 {
  99   VEC(constructor_elt,gc) *v = VEC_alloc (constructor_elt, gc, 3);
 100   constructor_elt *elt;
 101
 102   tree type = TREE_TYPE (var);
 103   tree field = TYPE_FIELDS (type);
 104
 105   elt = VEC_quick_push (constructor_elt, v, NULL);
 106   elt->index = field;
 107   elt->value = fold_convert (TREE_TYPE (field), tmpl_addr);
 108
 109   elt = VEC_quick_push (constructor_elt, v, NULL);
 110   field = TREE_CHAIN (field);
 111   elt->index = field;
 112   elt->value = build_int_cst (TREE_TYPE (field), 0);
 113
 114   elt = VEC_quick_push (constructor_elt, v, NULL);
 115   field = TREE_CHAIN (field);
 116   elt->index = field;
 117   elt->value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 118
 119   return build_constructor (type, v);
 120 }
 121
 122 /* Do VxWorks-specific parts of OVERRIDE_OPTIONS.  */
 123
 124 void
 125 vxworks_override_options (void)
 126 {
 127   /* We don't support __thread via target hooks.  */
 128   targetm.have_tls = false;
 129
 130   targetm.emutls.get_address = "__builtin___tls_lookup";
 131   targetm.emutls.register_common = NULL;
 132   targetm.emutls.var_section = ".tls_vars";
 133   targetm.emutls.tmpl_section = ".tls_data";
 134   targetm.emutls.var_prefix = "__tls__";
 135   targetm.emutls.tmpl_prefix = "";
 136   targetm.emutls.var_fields = vxworks_emutls_var_fields;
 137   targetm.emutls.var_init = vxworks_emutls_var_init;
 138   targetm.emutls.var_align_fixed = true;
 139   targetm.emutls.debug_form_tls_address = true;
 140
 141   /* We can use .ctors/.dtors sections only in RTP mode.  */
 142   targetm.have_ctors_dtors = TARGET_VXWORKS_RTP;
 143
 144   /* PIC is only supported for RTPs.  */
 145   if (flag_pic && !TARGET_VXWORKS_RTP)
 146     error ("PIC is only supported for RTPs");
 147 }