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comparison lwasm/symbol.c @ 363:d96c30e60ddf

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Added pass2 and various supporting logic including symbol lookups
author lost@starbug
date Tue, 06 Apr 2010 21:03:19 -0600
parents 7d91ab7ac7d6
children 6b33faa21a0a
comparison
equal deleted inserted replaced
362:4867f18c872f 363:d96c30e60ddf
63 return NULL; 63 return NULL;
64 } 64 }
65 } 65 }
66 66
67 if (islocal) 67 if (islocal)
68 context = as -> context; 68 context = cl -> context;
69 69
70 // first, look up symbol to see if it is already defined 70 // first, look up symbol to see if it is already defined
71 for (se = as -> symtab.head; se; se = se -> next) 71 for (se = as -> symtab.head; se; se = se -> next)
72 { 72 {
73 if (!strcmp(sym, se -> symbol)) 73 if (!strcmp(sym, se -> symbol))
93 if (flags & symbol_flag_set) 93 if (flags & symbol_flag_set)
94 { 94 {
95 version++; 95 version++;
96 } 96 }
97 97
98 // symplify the symbol expression - replaces "SET" symbols with
99 // symbol table entries
100 lwasm_reduce_expr(as, val);
101
98 se = lw_alloc(sizeof(struct symtabe)); 102 se = lw_alloc(sizeof(struct symtabe));
99 se -> next = as -> symtab.head; 103 se -> next = as -> symtab.head;
100 as -> symtab.head = se; 104 as -> symtab.head = se;
101 se -> context = context; 105 se -> context = context;
102 se -> version = version; 106 se -> version = version;
103 se -> flags = flags; 107 se -> flags = flags;
104 se -> value = lw_expr_copy(val); 108 se -> value = lw_expr_copy(val);
105 return se; 109 return se;
106 } 110 }
107 111
108 struct symtabe * lookup_symbol(asmstate_t *as, line_t *cl, char *sym, int context, int version) 112 // for "SET" symbols, always returns the LAST definition of the
113 // symbol. This works because the lwasm_reduce_expr() call in
114 // register_symbol will ensure there are no lingering "var" references
115 // to the set symbol anywhere in the symbol table; they will all be
116 // converted to direct references
117 // NOTE: this means that for a forward reference to a SET symbol,
118 // the LAST definition will be the one used.
119 // This arrangement also ensures that any reference to the symbol
120 // itself inside a "set" definition will refer to the previous version
121 // of the symbol.
122 struct symtabe * lookup_symbol(asmstate_t *as, line_t *cl, char *sym)
109 { 123 {
110 return NULL; 124 int local = 0;
125 struct symtabe *s, *s2;
126
127 // check if this is a local symbol
128 if (strchr(sym, '@') || strchr(sym, '?'))
129 local = 1;
130
131 if (cl && !CURPRAGMA(cl, PRAGMA_DOLLARNOTLOCAL) && strchr(sym, '$'))
132 local = 1;
133 if (!cl && !(as -> pragmas & PRAGMA_DOLLARNOTLOCAL) && strchr(sym, '$'))
134 local = 1;
135
136 // cannot look up local symbol in global context!!!!!
137 if (!cl && local)
138 return NULL;
139
140 for (s = as -> symtab.head, s2 = NULL; s; s = s -> next)
141 {
142 if (!strcmp(sym, s -> symbol))
143 {
144 if (local && s -> context != cl -> context)
145 continue;
146
147 if (s -> flags & symbol_flag_set)
148 {
149 // look for highest version of symbol
150 if (s -> version > s2 -> version)
151 s2 = s;
152 continue;
153 }
154 break;
155 }
156 }
157 if (!s && s2)
158 s = s2;
159
160 return s;
111 } 161 }