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)
  34 {
  35         struct scope *scope = __alloc_scope(0);
  36         memset(scope, 0, sizeof(*scope));
  37         scope->next = *s;
  38         *s = scope;
  39 }
  40
  41 void start_file_scope(void)
  42 {
  43         struct scope *scope = __alloc_scope(0);
  44
  45         memset(scope, 0, sizeof(*scope));
  46         scope->next = &builtin_scope;
  47         file_scope = scope;
  48
  49         /* top-level stuff defaults to file scope, "extern" etc will choose global scope */
  50         function_scope = scope;
  51         block_scope = scope;
  52 }
  53
  54 void start_symbol_scope(void)
  55 {
  56         start_scope(&block_scope);
  57 }
  58
  59 void start_function_scope(void)
  60 {
  61         start_scope(&function_scope);
  62         start_scope(&block_scope);
  63 }
  64
  65 static void remove_symbol_scope(struct symbol *sym)
  66 {
  67         struct symbol **ptr = &sym->ident->symbols;
  68
  69         while (*ptr != sym)
  70                 ptr = &(*ptr)->next_id;
  71         *ptr = sym->next_id;
  72 }
  73
  74 static void end_scope(struct scope **s)
  75 {
  76         struct scope *scope = *s;
  77         struct symbol_list *symbols = scope->symbols;
  78         struct symbol *sym;
  79
  80         *s = scope->next;
  81         scope->symbols = NULL;
  82         FOR_EACH_PTR(symbols, sym) {
  83                 remove_symbol_scope(sym);
  84         } END_FOR_EACH_PTR(sym);
  85 }
  86
  87 void end_file_scope(void)
  88 {
  89         end_scope(&file_scope);
  90 }
  91
  92 void new_file_scope(void)
  93 {
  94         if (file_scope != &builtin_scope)
  95                 end_file_scope();
  96         start_file_scope();
  97 }
  98
  99 void end_symbol_scope(void)
 100 {
 101         end_scope(&block_scope);
 102 }
 103
 104 void end_function_scope(void)
 105 {
 106         end_scope(&block_scope);
 107         end_scope(&function_scope);
 108 }
 109
 110 int is_outer_scope(struct scope *scope)
 111 {
 112         if (scope == block_scope)
 113                 return 0;
 114         if (scope == &builtin_scope && block_scope->next == &builtin_scope)
 115                 return 0;
 116         return 1;
 117 }
 118