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