1 /* Common VxWorks target definitions for GNU compiler. 2 Copyright (C) 2007, 2008 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 "toplev.h" 27 #include "output.h" 28 #include "tm.h" 29 #include "tree.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 (FIELD_DECL, get_identifier ("size"), 73 unsigned_type_node); 74 DECL_CONTEXT (field) = type; 75 next_field = field; 76 77 field = build_decl (FIELD_DECL, get_identifier ("module_id"), 78 unsigned_type_node); 79 DECL_CONTEXT (field) = type; 80 TREE_CHAIN (field) = next_field; 81 next_field = field; 82 83 field = build_decl (FIELD_DECL, get_identifier ("offset"), 84 unsigned_type_node); 85 DECL_CONTEXT (field) = type; 86 TREE_CHAIN (field) = next_field; 87 88 return field; 89 } 90 91 /* Return the CONSTRUCTOR to initialize an emulated TLS control 92 object. VAR is the control object. DECL is the TLS object itself 93 and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for 94 that object. */ 95 96 static tree 97 vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr) 98 { 99 VEC(constructor_elt,gc) *v = VEC_alloc (constructor_elt, gc, 3); 100 constructor_elt *elt; 101 102 tree type = TREE_TYPE (var); 103 tree field = TYPE_FIELDS (type); 104 105 elt = VEC_quick_push (constructor_elt, v, NULL); 106 elt->index = field; 107 elt->value = fold_convert (TREE_TYPE (field), tmpl_addr); 108 109 elt = VEC_quick_push (constructor_elt, v, NULL); 110 field = TREE_CHAIN (field); 111 elt->index = field; 112 elt->value = build_int_cst (TREE_TYPE (field), 0); 113 114 elt = VEC_quick_push (constructor_elt, v, NULL); 115 field = TREE_CHAIN (field); 116 elt->index = field; 117 elt->value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl)); 118 119 return build_constructor (type, v); 120 } 121 122 /* Do VxWorks-specific parts of OVERRIDE_OPTIONS. */ 123 124 void 125 vxworks_override_options (void) 126 { 127 /* We don't support __thread via target hooks. */ 128 targetm.have_tls = false; 129 130 targetm.emutls.get_address = "__builtin___tls_lookup"; 131 targetm.emutls.register_common = NULL; 132 targetm.emutls.var_section = ".tls_vars"; 133 targetm.emutls.tmpl_section = ".tls_data"; 134 targetm.emutls.var_prefix = "__tls__"; 135 targetm.emutls.tmpl_prefix = ""; 136 targetm.emutls.var_fields = vxworks_emutls_var_fields; 137 targetm.emutls.var_init = vxworks_emutls_var_init; 138 targetm.emutls.var_align_fixed = true; 139 targetm.emutls.debug_form_tls_address = true; 140 141 /* We can use .ctors/.dtors sections only in RTP mode. */ 142 targetm.have_ctors_dtors = TARGET_VXWORKS_RTP; 143 144 /* PIC is only supported for RTPs. */ 145 if (flag_pic && !TARGET_VXWORKS_RTP) 146 error ("PIC is only supported for RTPs"); 147 } 148