1 /* Common VxWorks target definitions for GNU compiler. 2 Copyright (C) 2007-2018 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 /* 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 (BUILTINS_LOCATION, FIELD_DECL, 73 get_identifier ("size"), unsigned_type_node); 74 DECL_CONTEXT (field) = type; 75 next_field = field; 76 77 field = build_decl (BUILTINS_LOCATION, FIELD_DECL, 78 get_identifier ("module_id"), unsigned_type_node); 79 DECL_CONTEXT (field) = type; 80 DECL_CHAIN (field) = next_field; 81 next_field = field; 82 83 /* The offset field is declared as an unsigned int with pointer mode. */ 84 field = build_decl (BUILTINS_LOCATION, FIELD_DECL, 85 get_identifier ("offset"), long_unsigned_type_node); 86 87 DECL_CONTEXT (field) = type; 88 DECL_CHAIN (field) = next_field; 89 90 return field; 91 } 92 93 /* Return the CONSTRUCTOR to initialize an emulated TLS control 94 object. VAR is the control object. DECL is the TLS object itself 95 and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for 96 that object. */ 97 98 static tree 99 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr) 100 { 101 vec<constructor_elt, va_gc> *v; 102 vec_alloc (v, 3); 103 104 tree type = TREE_TYPE (var); 105 tree field = TYPE_FIELDS (type); 106 107 constructor_elt elt = {field, fold_convert (TREE_TYPE (field), tmpl_addr)}; 108 v->quick_push (elt); 109 110 field = DECL_CHAIN (field); 111 elt.index = field; 112 elt.value = build_int_cst (TREE_TYPE (field), 0); 113 v->quick_push (elt); 114 115 field = DECL_CHAIN (field); 116 elt.index = field; 117 elt.value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl)); 118 v->quick_push (elt); 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 /* Setup the tls emulation bits if the OS misses proper 129 tls support. */ 130 targetm.have_tls = VXWORKS_HAVE_TLS; 131 132 if (!VXWORKS_HAVE_TLS) 133 { 134 targetm.emutls.get_address = "__builtin___tls_lookup"; 135 targetm.emutls.register_common = NULL; 136 targetm.emutls.var_section = ".tls_vars"; 137 targetm.emutls.tmpl_section = ".tls_data"; 138 targetm.emutls.var_prefix = "__tls__"; 139 targetm.emutls.tmpl_prefix = ""; 140 targetm.emutls.var_fields = vxworks_emutls_var_fields; 141 targetm.emutls.var_init = vxworks_emutls_var_init; 142 targetm.emutls.var_align_fixed = true; 143 targetm.emutls.debug_form_tls_address = true; 144 } 145 146 /* We can use .ctors/.dtors sections only in RTP mode. */ 147 targetm.have_ctors_dtors = TARGET_VXWORKS_RTP; 148 149 /* PIC is only supported for RTPs. */ 150 if (flag_pic && !TARGET_VXWORKS_RTP) 151 error ("PIC is only supported for RTPs"); 152 153 /* VxWorks comes with non-gdb debuggers which only support strict 154 dwarf up to certain version. Default dwarf control to friendly 155 values for these. */ 156 157 if (!global_options_set.x_dwarf_strict) 158 dwarf_strict = 1; 159 160 if (!global_options_set.x_dwarf_version) 161 dwarf_version = VXWORKS_DWARF_VERSION_DEFAULT; 162 } 163