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  *  Licensed under the Open Software License version 1.1
  10  */
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <stdio.h>
  14
  15 #include "lib.h"
  16 #include "allocate.h"
  17 #include "symbol.h"
  18 #include "scope.h"
  19
  20 static struct scope builtin_scope = { .next = &builtin_scope };
  21
  22 struct scope    *block_scope = &builtin_scope,          // regular automatic variables etc
  23                 *function_scope = &builtin_scope,       // labels, arguments etc
  24                 *file_scope = &builtin_scope,           // static
  25                 *global_scope = &builtin_scope;         // externally visible
  26
  27 void bind_scope(struct symbol *sym, struct scope *scope)
  28 {
  29         sym->scope = scope;
  30         add_symbol(&scope->symbols, sym);
  31 }
  32
  33 static void start_scope(struct scope **s, struct position pos)
  34 {
  35         struct scope *scope = __alloc_scope(0);
  36         memset(scope, 0, sizeof(*scope));
  37         scope->token = __alloc_token(0);
  38         scope->token->pos = pos;
  39         scope->next = *s;
  40         *s = scope;
  41 }
  42
  43 void start_file_scope(void)
  44 {
  45         struct scope *scope = __alloc_scope(0);
  46
  47         memset(scope, 0, sizeof(*scope));
  48         scope->next = &builtin_scope;
  49         file_scope = scope;
  50
  51         /* top-level stuff defaults to file scope, "extern" etc will choose global scope */
  52         function_scope = scope;
  53         block_scope = scope;
  54 }
  55
  56 void start_symbol_scope(struct position pos)
  57 {
  58         start_scope(&block_scope, pos);
  59 }
  60
  61 void start_function_scope(struct position pos)
  62 {
  63         start_scope(&function_scope, pos);
  64         start_scope(&block_scope, pos);
  65 }
  66
  67 static void remove_symbol_scope(struct symbol *sym)
  68 {
  69         struct symbol **ptr = &sym->ident->symbols;
  70
  71         while (*ptr != sym)
  72                 ptr = &(*ptr)->next_id;
  73         *ptr = sym->next_id;
  74 }
  75
  76 static void end_scope(struct scope **s)
  77 {
  78         struct scope *scope = *s;
  79         struct symbol_list *symbols = scope->symbols;
  80         struct symbol *sym;
  81
  82         *s = scope->next;
  83         scope->symbols = NULL;
  84         FOR_EACH_PTR(symbols, sym) {
  85                 remove_symbol_scope(sym);
  86         } END_FOR_EACH_PTR(sym);
  87 }
  88
  89 void end_file_scope(void)
  90 {
  91         end_scope(&file_scope);
  92 }
  93
  94 void new_file_scope(void)
  95 {
  96         if (file_scope != &builtin_scope)
  97                 end_file_scope();
  98         start_file_scope();
  99 }
 100
 101 void end_symbol_scope(void)
 102 {
 103         end_scope(&block_scope);
 104 }
 105
 106 void end_function_scope(void)
 107 {
 108         end_scope(&block_scope);
 109         end_scope(&function_scope);
 110 }
 111
 112 int is_outer_scope(struct scope *scope)
 113 {
 114         if (scope == block_scope)
 115                 return 0;
 116         if (scope == &builtin_scope && block_scope->next == &builtin_scope)
 117                 return 0;
 118         return 1;
 119 }
 120