scope.c

   1 /*
   2  * Symbol scoping.
   3  *
   4  * This is pretty trivial.
   5  *
   6  * Copyright (C) 2003 Transmeta Corp.
   7  *               2003-2004 Linus Torvalds
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  22  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25  * THE SOFTWARE.
  26  */
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <stdio.h>
  30
  31 #include "lib.h"
  32 #include "allocate.h"
  33 #include "symbol.h"
  34 #include "scope.h"
  35
  36 static struct scope builtin_scope = { .next = &builtin_scope };
  37
  38 struct scope    *block_scope = &builtin_scope,          // regular automatic variables etc
  39                 *function_scope = &builtin_scope,       // labels, arguments etc
  40                 *file_scope = &builtin_scope,           // static
  41                 *global_scope = &builtin_scope;         // externally visible
  42
  43 void bind_scope(struct symbol *sym, struct scope *scope)
  44 {
  45         sym->scope = scope;
  46         add_symbol(&scope->symbols, sym);
  47 }
  48
  49 void rebind_scope(struct symbol *sym, struct scope *new)
  50 {
  51         struct scope *old = sym->scope;
  52
  53         if (old == new)
  54                 return;
  55
  56         if (old)
  57                 delete_ptr_list_entry((struct ptr_list**) &old->symbols, sym, 1);
  58
  59         bind_scope(sym, new);
  60 }
  61
  62 static void start_scope(struct scope **s, struct position pos)
  63 {
  64         struct scope *scope = __alloc_scope(0);
  65         memset(scope, 0, sizeof(*scope));
  66         scope->token = __alloc_token(0);
  67         scope->token->pos = pos;
  68         scope->next = *s;
  69         *s = scope;
  70 }
  71
  72 void start_file_scope(void)
  73 {
  74         struct scope *scope = __alloc_scope(0);
  75
  76         memset(scope, 0, sizeof(*scope));
  77         scope->next = &builtin_scope;
  78         file_scope = scope;
  79
  80         /* top-level stuff defaults to file scope, "extern" etc will choose global scope */
  81         function_scope = scope;
  82         block_scope = scope;
  83 }
  84
  85 void start_symbol_scope(struct position pos)
  86 {
  87         start_scope(&block_scope, pos);
  88 }
  89
  90 void start_function_scope(struct position pos)
  91 {
  92         start_scope(&function_scope, pos);
  93         start_scope(&block_scope, pos);
  94 }
  95
  96 static void remove_symbol_scope(struct symbol *sym)
  97 {
  98         struct symbol **ptr = &sym->ident->symbols;
  99
 100         while (*ptr != sym)
 101                 ptr = &(*ptr)->next_id;
 102         *ptr = sym->next_id;
 103 }
 104
 105 static void end_scope(struct scope **s)
 106 {
 107         struct scope *scope = *s;
 108         struct symbol_list *symbols = scope->symbols;
 109         struct symbol *sym;
 110
 111         *s = scope->next;
 112         scope->symbols = NULL;
 113         FOR_EACH_PTR(symbols, sym) {
 114                 remove_symbol_scope(sym);
 115         } END_FOR_EACH_PTR(sym);
 116 }
 117
 118 void end_file_scope(void)
 119 {
 120         end_scope(&file_scope);
 121 }
 122
 123 void new_file_scope(void)
 124 {
 125         if (file_scope != &builtin_scope)
 126                 end_file_scope();
 127         start_file_scope();
 128 }
 129
 130 void end_symbol_scope(void)
 131 {
 132         end_scope(&block_scope);
 133 }
 134
 135 void end_function_scope(void)
 136 {
 137         end_scope(&block_scope);
 138         end_scope(&function_scope);
 139 }
 140
 141 int is_outer_scope(struct scope *scope)
 142 {
 143         if (scope == block_scope)
 144                 return 0;
 145         if (scope == &builtin_scope && block_scope->next == &builtin_scope)
 146                 return 0;
 147         return 1;
 148 }
 149