gcc/config/vxworks.c

   1 /* Common VxWorks target definitions for GNU compiler.
   2    Copyright (C) 2007-2021 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
  34 #if !HAVE_INITFINI_ARRAY_SUPPORT
  35 /* Like default_named_section_asm_out_constructor, except that even
  36    constructors with DEFAULT_INIT_PRIORITY must go in a numbered
  37    section on VxWorks.  The VxWorks runtime uses a clever trick to get
  38    the sentinel entry (-1) inserted at the beginning of the .ctors
  39    segment.  This trick will not work if we ever generate any entries
  40    in plain .ctors sections; we must always use .ctors.PRIORITY.  */
  41
  42 void
  43 vxworks_asm_out_constructor (rtx symbol, int priority)
  44 {
  45   section *sec;
  46
  47   sec = get_cdtor_priority_section (priority,
  48                                     /*constructor_p=*/true);
  49   assemble_addr_to_section (symbol, sec);
  50 }
  51
  52 /* See comment for vxworks_asm_out_constructor.  */
  53
  54 void
  55 vxworks_asm_out_destructor (rtx symbol, int priority)
  56 {
  57   section *sec;
  58
  59   sec = get_cdtor_priority_section (priority,
  60                                     /*constructor_p=*/false);
  61   assemble_addr_to_section (symbol, sec);
  62 }
  63 #endif
  64
  65 /* Return the list of FIELD_DECLs that make up an emulated TLS
  66    variable's control object.  TYPE is the structure these are fields
  67    of and *NAME will be filled in with the structure tag that should
  68    be used.  */
  69
  70 static tree
  71 vxworks_emutls_var_fields (tree type, tree *name)
  72 {
  73   tree field, next_field;
  74
  75   *name = get_identifier ("__tls_var");
  76
  77   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  78                       get_identifier ("size"), unsigned_type_node);
  79   DECL_CONTEXT (field) = type;
  80   next_field = field;
  81
  82   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  83                       get_identifier ("module_id"), unsigned_type_node);
  84   DECL_CONTEXT (field) = type;
  85   DECL_CHAIN (field) = next_field;
  86   next_field = field;
  87
  88   /* The offset field is declared as an unsigned int with pointer mode.  */
  89   field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
  90                       get_identifier ("offset"), long_unsigned_type_node);
  91
  92   DECL_CONTEXT (field) = type;
  93   DECL_CHAIN (field) = next_field;
  94
  95   return field;
  96 }
  97
  98 /* Return the CONSTRUCTOR to initialize an emulated TLS control
  99    object.  VAR is the control object.  DECL is the TLS object itself
 100    and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for
 101    that object.  */
 102
 103 static tree
 104 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
 105 {
 106   vec<constructor_elt, va_gc> *v;
 107   vec_alloc (v, 3);
 108
 109   tree type = TREE_TYPE (var);
 110   tree field = TYPE_FIELDS (type);
 111
 112   constructor_elt elt = {field, fold_convert (TREE_TYPE (field), tmpl_addr)};
 113   v->quick_push (elt);
 114
 115   field = DECL_CHAIN (field);
 116   elt.index = field;
 117   elt.value = build_int_cst (TREE_TYPE (field), 0);
 118   v->quick_push (elt);
 119
 120   field = DECL_CHAIN (field);
 121   elt.index = field;
 122   elt.value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
 123   v->quick_push (elt);
 124
 125   return build_constructor (type, v);
 126 }
 127
 128 /* Do VxWorks-specific parts of TARGET_OPTION_OVERRIDE.  */
 129
 130 void
 131 vxworks_override_options (void)
 132 {
 133   /* Setup the tls emulation bits if the OS misses proper
 134      tls support.  */
 135   targetm.have_tls = VXWORKS_HAVE_TLS;
 136
 137   if (!VXWORKS_HAVE_TLS)
 138     {
 139       targetm.emutls.get_address = "__builtin___tls_lookup";
 140       targetm.emutls.register_common = NULL;
 141       targetm.emutls.var_section = ".tls_vars";
 142       targetm.emutls.tmpl_section = ".tls_data";
 143       targetm.emutls.var_prefix = "__tls__";
 144       targetm.emutls.tmpl_prefix = "";
 145       targetm.emutls.var_fields = vxworks_emutls_var_fields;
 146       targetm.emutls.var_init = vxworks_emutls_var_init;
 147       targetm.emutls.var_align_fixed = true;
 148       targetm.emutls.debug_form_tls_address = true;
 149     }
 150
 151   /* Arrange to use .ctors/.dtors sections if the target VxWorks configuration
 152      and mode supports it, or the init/fini_array sections if we were
 153      configured with --enable-initfini-array explicitly.  In the latter case,
 154      the toolchain user is expected to provide whatever linker level glue is
 155      required to get things to operate properly.  */
 156
 157   targetm.have_ctors_dtors =
 158     TARGET_VXWORKS_HAVE_CTORS_DTORS || HAVE_INITFINI_ARRAY_SUPPORT;
 159
 160   /* PIC is only supported for RTPs.  flags_pic might be < 0 here, in
 161      contexts where the corresponding switches are not processed,
 162      e.g. from --help.  We are not generating code in such cases.  */
 163   if (flag_pic > 0 && !TARGET_VXWORKS_RTP)
 164     error ("PIC is only supported for RTPs");
 165
 166   /* VxWorks comes with non-gdb debuggers which only support strict
 167      dwarf up to certain version.  Default dwarf control to friendly
 168      values for these.  */
 169
 170   if (!global_options_set.x_dwarf_strict)
 171     dwarf_strict = 1;
 172
 173   if (!global_options_set.x_dwarf_version)
 174     dwarf_version = VXWORKS_DWARF_VERSION_DEFAULT;
 175
 176 }
 177
 178 /* We don't want to use library symbol __clear_cache on SR0640.  Avoid
 179    it and issue a direct call to cacheTextUpdate.  It takes a size_t
 180    length rather than the END address, so we have to compute it.  */
 181
 182 void
 183 vxworks_emit_call_builtin___clear_cache (rtx begin, rtx end)
 184 {
 185   /* STATUS cacheTextUpdate (void *, size_t); */
 186   rtx callee = gen_rtx_SYMBOL_REF (Pmode, "cacheTextUpdate");
 187
 188   enum machine_mode size_mode = TYPE_MODE (sizetype);
 189
 190   rtx len = simplify_gen_binary (MINUS, size_mode, end, begin);
 191
 192   emit_library_call (callee,
 193                      LCT_NORMAL, VOIDmode,
 194                      begin, ptr_mode,
 195                      len, size_mode);
 196 }