gcc/config/vxworks.c

   1 /* Common VxWorks target definitions for GNU compiler.
   2    Copyright (C) 2007, 2008, 2010
   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 "diagnostic-core.h"
  27 #include "toplev.h"
  28 #include "output.h"
  29 #include "tm.h"
  30 #include "tree.h"
  31
  32 /* Like default_named_section_asm_out_constructor, except that even
  33    constructors with DEFAULT_INIT_PRIORITY must go in a numbered
  34    section on VxWorks.  The VxWorks runtime uses a clever trick to get
  35    the sentinel entry (-1) inserted at the beginning of the .ctors
  36    segment.  This trick will not work if we ever generate any entries
  37    in plain .ctors sections; we must always use .ctors.PRIORITY.  */
  38
  39 void
  40 vxworks_asm_out_constructor (rtx symbol, int priority)
  41 {
  42   section *sec;
  43
  44   sec = get_cdtor_priority_section (priority,
  45                                     /*constructor_p=*/true);
  46   assemble_addr_to_section (symbol, sec);
  47 }
  48
  49 /* See comment for vxworks_asm_out_constructor.  */
  50
  51 void
  52 vxworks_asm_out_destructor (rtx symbol, int priority)
  53 {
  54   section *sec;
  55
  56   sec = get_cdtor_priority_section (priority,
  57                                     /*constructor_p=*/false);
  58   assemble_addr_to_section (symbol, sec);
  59 }
  60
  61 /* Return the list of FIELD_DECLs that make up an emulated TLS
  62    variable's control object.  TYPE is the structure these are fields
  63    of and *NAME will be filled in with the structure tag that should
  64    be used.  */
  65
  66 static tree
  67 vxworks_emutls_var_fields (tree type, tree *name)
  68 {
  69   tree field, next_field;
  70
  71   *name = get_identifier ("__tls_var");
  72
  73   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  74                       get_identifier ("size"), unsigned_type_node);
  75   DECL_CONTEXT (field) = type;
  76   next_field = field;
  77
  78   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  79                       get_identifier ("module_id"), unsigned_type_node);
  80   DECL_CONTEXT (field) = type;
  81   DECL_CHAIN (field) = next_field;
  82   next_field = field;
  83
  84   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  85                       get_identifier ("offset"), unsigned_type_node);
  86   DECL_CONTEXT (field) = type;
  87   DECL_CHAIN (field) = next_field;
  88
  89   return field;
  90 }
  91
  92 /* Return the CONSTRUCTOR to initialize an emulated TLS control
  93    object.  VAR is the control object.  DECL is the TLS object itself
  94    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
  95    that object.  */
  96
  97 static tree
  98 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
  99 {
 100   VEC(constructor_elt,gc) *v = VEC_alloc (constructor_elt, gc, 3);
 101   constructor_elt *elt;
 102
 103   tree type = TREE_TYPE (var);
 104   tree field = TYPE_FIELDS (type);
 105
 106   elt = VEC_quick_push (constructor_elt, v, NULL);
 107   elt->index = field;
 108   elt->value = fold_convert (TREE_TYPE (field), tmpl_addr);
 109
 110   elt = VEC_quick_push (constructor_elt, v, NULL);
 111   field = DECL_CHAIN (field);
 112   elt->index = field;
 113   elt->value = build_int_cst (TREE_TYPE (field), 0);
 114
 115   elt = VEC_quick_push (constructor_elt, v, NULL);
 116   field = DECL_CHAIN (field);
 117   elt->index = field;
 118   elt->value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 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   /* We don't support __thread via target hooks.  */
 129   targetm.have_tls = false;
 130
 131   targetm.emutls.get_address = "__builtin___tls_lookup";
 132   targetm.emutls.register_common = NULL;
 133   targetm.emutls.var_section = ".tls_vars";
 134   targetm.emutls.tmpl_section = ".tls_data";
 135   targetm.emutls.var_prefix = "__tls__";
 136   targetm.emutls.tmpl_prefix = "";
 137   targetm.emutls.var_fields = vxworks_emutls_var_fields;
 138   targetm.emutls.var_init = vxworks_emutls_var_init;
 139   targetm.emutls.var_align_fixed = true;
 140   targetm.emutls.debug_form_tls_address = true;
 141
 142   /* We can use .ctors/.dtors sections only in RTP mode.  */
 143   targetm.have_ctors_dtors = TARGET_VXWORKS_RTP;
 144
 145   /* PIC is only supported for RTPs.  */
 146   if (flag_pic && !TARGET_VXWORKS_RTP)
 147     error ("PIC is only supported for RTPs");
 148 }