gcc/config/vxworks.c

   1 /* Common VxWorks target definitions for GNU compiler.
   2    Copyright (C) 2007-2020 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 #if !HAVE_INITFINI_ARRAY_SUPPORT
  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 #endif
  61
  62 /* Return the list of FIELD_DECLs that make up an emulated TLS
  63    variable's control object.  TYPE is the structure these are fields
  64    of and *NAME will be filled in with the structure tag that should
  65    be used.  */
  66
  67 static tree
  68 vxworks_emutls_var_fields (tree type, tree *name)
  69 {
  70   tree field, next_field;
  71
  72   *name = get_identifier ("__tls_var");
  73
  74   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  75                       get_identifier ("size"), unsigned_type_node);
  76   DECL_CONTEXT (field) = type;
  77   next_field = field;
  78
  79   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  80                       get_identifier ("module_id"), unsigned_type_node);
  81   DECL_CONTEXT (field) = type;
  82   DECL_CHAIN (field) = next_field;
  83   next_field = field;
  84
  85   /* The offset field is declared as an unsigned int with pointer mode.  */
  86   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  87                       get_identifier ("offset"), long_unsigned_type_node);
  88
  89   DECL_CONTEXT (field) = type;
  90   DECL_CHAIN (field) = next_field;
  91
  92   return field;
  93 }
  94
  95 /* Return the CONSTRUCTOR to initialize an emulated TLS control
  96    object.  VAR is the control object.  DECL is the TLS object itself
  97    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
  98    that object.  */
  99
 100 static tree
 101 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
 102 {
 103   vec<constructor_elt, va_gc> *v;
 104   vec_alloc (v, 3);
 105
 106   tree type = TREE_TYPE (var);
 107   tree field = TYPE_FIELDS (type);
 108
 109   constructor_elt elt = {field, fold_convert (TREE_TYPE (field), tmpl_addr)};
 110   v->quick_push (elt);
 111
 112   field = DECL_CHAIN (field);
 113   elt.index = field;
 114   elt.value = build_int_cst (TREE_TYPE (field), 0);
 115   v->quick_push (elt);
 116
 117   field = DECL_CHAIN (field);
 118   elt.index = field;
 119   elt.value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 120   v->quick_push (elt);
 121
 122   return build_constructor (type, v);
 123 }
 124
 125 /* Do VxWorks-specific parts of TARGET_OPTION_OVERRIDE.  */
 126
 127 void
 128 vxworks_override_options (void)
 129 {
 130   /* Setup the tls emulation bits if the OS misses proper
 131      tls support.  */
 132   targetm.have_tls = VXWORKS_HAVE_TLS;
 133
 134   if (!VXWORKS_HAVE_TLS)
 135     {
 136       targetm.emutls.get_address = "__builtin___tls_lookup";
 137       targetm.emutls.register_common = NULL;
 138       targetm.emutls.var_section = ".tls_vars";
 139       targetm.emutls.tmpl_section = ".tls_data";
 140       targetm.emutls.var_prefix = "__tls__";
 141       targetm.emutls.tmpl_prefix = "";
 142       targetm.emutls.var_fields = vxworks_emutls_var_fields;
 143       targetm.emutls.var_init = vxworks_emutls_var_init;
 144       targetm.emutls.var_align_fixed = true;
 145       targetm.emutls.debug_form_tls_address = true;
 146     }
 147
 148   /* Arrange to use .ctors/.dtors sections if the target VxWorks configuration
 149      and mode supports it, or the init/fini_array sections if we were
 150      configured with --enable-initfini-array explicitly.  In the latter case,
 151      the toolchain user is expected to provide whatever linker level glue is
 152      required to get things to operate properly.  */
 153
 154   targetm.have_ctors_dtors =
 155     TARGET_VXWORKS_HAVE_CTORS_DTORS || HAVE_INITFINI_ARRAY_SUPPORT;
 156
 157   /* PIC is only supported for RTPs.  */
 158   if (flag_pic && !TARGET_VXWORKS_RTP)
 159     error ("PIC is only supported for RTPs");
 160
 161   /* VxWorks comes with non-gdb debuggers which only support strict
 162      dwarf up to certain version.  Default dwarf control to friendly
 163      values for these.  */
 164
 165   if (!global_options_set.x_dwarf_strict)
 166     dwarf_strict = 1;
 167
 168   if (!global_options_set.x_dwarf_version)
 169     dwarf_version = VXWORKS_DWARF_VERSION_DEFAULT;
 170 }