gcc/config/vxworks.cc

   1 /* Common VxWorks target definitions for GNU compiler.
   2    Copyright (C) 2007-2024 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 #include "rtl.h"
  31 #include "memmodel.h"
  32 #include "optabs.h"
  33 #include "opts.h"
  34
  35 #if !HAVE_INITFINI_ARRAY_SUPPORT
  36 /* Like default_named_section_asm_out_constructor, except that even
  37    constructors with DEFAULT_INIT_PRIORITY must go in a numbered
  38    section on VxWorks.  The VxWorks runtime uses a clever trick to get
  39    the sentinel entry (-1) inserted at the beginning of the .ctors
  40    segment.  This trick will not work if we ever generate any entries
  41    in plain .ctors sections; we must always use .ctors.PRIORITY.  */
  42
  43 void
  44 vxworks_asm_out_constructor (rtx symbol, int priority)
  45 {
  46   section *sec;
  47
  48   sec = get_cdtor_priority_section (priority,
  49                                     /*constructor_p=*/true);
  50   assemble_addr_to_section (symbol, sec);
  51 }
  52
  53 /* See comment for vxworks_asm_out_constructor.  */
  54
  55 void
  56 vxworks_asm_out_destructor (rtx symbol, int priority)
  57 {
  58   section *sec;
  59
  60   sec = get_cdtor_priority_section (priority,
  61                                     /*constructor_p=*/false);
  62   assemble_addr_to_section (symbol, sec);
  63 }
  64 #endif
  65
  66 /* Return the list of FIELD_DECLs that make up an emulated TLS
  67    variable's control object.  TYPE is the structure these are fields
  68    of and *NAME will be filled in with the structure tag that should
  69    be used.  */
  70
  71 static tree
  72 vxworks_emutls_var_fields (tree type, tree *name)
  73 {
  74   tree field, next_field;
  75
  76   *name = get_identifier ("__tls_var");
  77
  78   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  79                       get_identifier ("size"), unsigned_type_node);
  80   DECL_CONTEXT (field) = type;
  81   next_field = field;
  82
  83   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  84                       get_identifier ("module_id"), unsigned_type_node);
  85   DECL_CONTEXT (field) = type;
  86   DECL_CHAIN (field) = next_field;
  87   next_field = field;
  88
  89   /* The offset field is declared as an unsigned int with pointer mode.  */
  90   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  91                       get_identifier ("offset"), long_unsigned_type_node);
  92
  93   DECL_CONTEXT (field) = type;
  94   DECL_CHAIN (field) = next_field;
  95
  96   return field;
  97 }
  98
  99 /* Return the CONSTRUCTOR to initialize an emulated TLS control
 100    object.  VAR is the control object.  DECL is the TLS object itself
 101    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
 102    that object.  */
 103
 104 static tree
 105 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
 106 {
 107   vec<constructor_elt, va_gc> *v;
 108   vec_alloc (v, 3);
 109
 110   tree type = TREE_TYPE (var);
 111   tree field = TYPE_FIELDS (type);
 112
 113   constructor_elt elt = {field, fold_convert (TREE_TYPE (field), tmpl_addr)};
 114   v->quick_push (elt);
 115
 116   field = DECL_CHAIN (field);
 117   elt.index = field;
 118   elt.value = build_int_cst (TREE_TYPE (field), 0);
 119   v->quick_push (elt);
 120
 121   field = DECL_CHAIN (field);
 122   elt.index = field;
 123   elt.value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 124   v->quick_push (elt);
 125
 126   return build_constructor (type, v);
 127 }
 128
 129 /* Do VxWorks-specific parts of TARGET_OPTION_OVERRIDE.  */
 130
 131 void
 132 vxworks_override_options (void)
 133 {
 134   /* Setup the tls emulation bits if the OS misses proper
 135      tls support.  */
 136   targetm.have_tls = VXWORKS_HAVE_TLS;
 137
 138   if (!VXWORKS_HAVE_TLS)
 139     {
 140       targetm.emutls.get_address = "__builtin___tls_lookup";
 141       targetm.emutls.register_common = NULL;
 142       targetm.emutls.var_section = ".tls_vars";
 143       targetm.emutls.tmpl_section = ".tls_data";
 144       targetm.emutls.var_prefix = "__tls__";
 145       targetm.emutls.tmpl_prefix = "";
 146       targetm.emutls.var_fields = vxworks_emutls_var_fields;
 147       targetm.emutls.var_init = vxworks_emutls_var_init;
 148       targetm.emutls.var_align_fixed = true;
 149       targetm.emutls.debug_form_tls_address = true;
 150     }
 151
 152   /* Arrange to use .ctors/.dtors sections if the target VxWorks configuration
 153      and mode supports it, or the init/fini_array sections if we were
 154      configured with --enable-initfini-array explicitly.  In the latter case,
 155      the toolchain user is expected to provide whatever linker level glue is
 156      required to get things to operate properly.  */
 157
 158   targetm.have_ctors_dtors =
 159     TARGET_VXWORKS_HAVE_CTORS_DTORS || HAVE_INITFINI_ARRAY_SUPPORT;
 160
 161   /* PIC is only supported for RTPs.  flags_pic might be < 0 here, in
 162      contexts where the corresponding switches are not processed,
 163      e.g. from --help.  We are not generating code in such cases.  */
 164   if (flag_pic > 0 && !TARGET_VXWORKS_RTP)
 165     error ("PIC is only supported for RTPs");
 166
 167   /* VxWorks comes with non-gdb debuggers which only support strict dwarf
 168      up to certain versions, as controlled by DWARF_VERSION_DEFAULT.  */
 169   if (!OPTION_SET_P (dwarf_strict))
 170     dwarf_strict = 1;
 171 }
 172
 173 /* We don't want to use library symbol __clear_cache on SR0640.  Avoid
 174    it and issue a direct call to cacheTextUpdate.  It takes a size_t
 175    length rather than the END address, so we have to compute it.  */
 176
 177 void
 178 vxworks_emit_call_builtin___clear_cache (rtx begin, rtx end)
 179 {
 180   /* STATUS cacheTextUpdate (void *, size_t); */
 181   rtx callee = gen_rtx_SYMBOL_REF (Pmode, "cacheTextUpdate");
 182
 183   enum machine_mode size_mode = TYPE_MODE (sizetype);
 184
 185   rtx len = simplify_gen_binary (MINUS, size_mode, end, begin);
 186
 187   emit_library_call (callee,
 188                      LCT_NORMAL, VOIDmode,
 189                      begin, ptr_mode,
 190                      len, size_mode);
 191 }