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
  50 void rebind_scope(struct symbol *sym, struct scope *new)
  51 {
  52         struct scope *old = sym->scope;
  53
  54         if (old == new)
  55                 return;
  56
  57         if (old)
  58                 delete_ptr_list_entry((struct ptr_list**) &old->symbols, sym, 1);
  59
  60         bind_scope(sym, new);
  61 }
  62
  63 static void start_scope(struct scope **s)
  64 {
  65         struct scope *scope = __alloc_scope(0);
  66         memset(scope, 0, sizeof(*scope));
  67         scope->next = *s;
  68         *s = scope;
  69 }
  70
  71 void start_file_scope(void)
  72 {
  73         struct scope *scope = __alloc_scope(0);
  74
  75         memset(scope, 0, sizeof(*scope));
  76         scope->next = &builtin_scope;
  77         file_scope = scope;
  78
  79         /* top-level stuff defaults to file scope, "extern" etc will choose global scope */
  80         function_scope = scope;
  81         block_scope = scope;
  82 }
  83
  84 void start_symbol_scope(void)
  85 {
  86         start_scope(&block_scope);
  87 }
  88
  89 void start_function_scope(void)
  90 {
  91         start_scope(&function_scope);
  92         start_scope(&block_scope);
  93 }
  94
  95 static void remove_symbol_scope(struct symbol *sym)
  96 {
  97         struct symbol **ptr = &sym->ident->symbols;
  98
  99         while (*ptr != sym)
 100                 ptr = &(*ptr)->next_id;
 101         *ptr = sym->next_id;
 102 }
 103
 104 static void end_scope(struct scope **s)
 105 {
 106         struct scope *scope = *s;
 107         struct symbol_list *symbols = scope->symbols;
 108         struct symbol *sym;
 109
 110         *s = scope->next;
 111         scope->symbols = NULL;
 112         FOR_EACH_PTR(symbols, sym) {
 113                 remove_symbol_scope(sym);
 114         } END_FOR_EACH_PTR(sym);
 115 }
 116
 117 void end_file_scope(void)
 118 {
 119         end_scope(&file_scope);
 120 }
 121
 122 void new_file_scope(void)
 123 {
 124         if (file_scope != &builtin_scope)
 125                 end_file_scope();
 126         start_file_scope();
 127 }
 128
 129 void end_symbol_scope(void)
 130 {
 131         end_scope(&block_scope);
 132 }
 133
 134 void end_function_scope(void)
 135 {
 136         end_scope(&block_scope);
 137         end_scope(&function_scope);
 138 }
 139
 140 int is_outer_scope(struct scope *scope)
 141 {
 142         if (scope == block_scope)
 143                 return 0;
 144         if (scope == &builtin_scope && block_scope->next == &builtin_scope)
 145                 return 0;
 146         return 1;
 147 }
 148