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Filter: Implement soft scopes
Soft scopes are anonymous scopes that most likely do not contain any symbol, so allocating regular scope is postponed when it is really needed.
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@ -574,6 +574,8 @@ check_eof(void)
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return 0;
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}
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static inline void cf_swap_soft_scope(void);
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static struct symbol *
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cf_new_symbol(const byte *c)
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{
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@ -583,6 +585,8 @@ cf_new_symbol(const byte *c)
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if (l > SYM_MAX_LEN)
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cf_error("Symbol too long");
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cf_swap_soft_scope();
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s = cfg_allocz(sizeof(struct symbol) + l + 1);
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*s = (struct symbol) { .scope = conf_this_scope, .class = SYM_VOID, };
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strcpy(s->name, c);
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@ -654,10 +658,10 @@ cf_localize_symbol(struct symbol *sym)
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/* If the symbol type is void, it has been recently allocated just in this scope. */
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if (!sym->class)
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return sym;
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/* If the scope is the current, it is already defined in this scope. */
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if (sym->scope == conf_this_scope)
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cf_error("Symbol already defined");
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if (cf_symbol_is_local(sym))
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cf_error("Symbol '%s' already defined", sym->name);
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/* Not allocated here yet, doing it now. */
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return cf_new_symbol(sym->name);
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@ -787,12 +791,60 @@ cf_push_scope(struct symbol *sym)
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void
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cf_pop_scope(void)
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{
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ASSERT(!conf_this_scope->soft_scopes);
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conf_this_scope->active = 0;
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conf_this_scope = conf_this_scope->next;
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ASSERT(conf_this_scope);
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}
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/**
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* cf_push_soft_scope - enter new soft scope
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*
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* If we want to enter a new anonymous scope that most likely will not contain
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* any symbols, we can use cf_push_soft_scope() insteas of cf_push_scope().
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* Such scope will be converted to a regular scope on first use.
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*/
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void
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cf_push_soft_scope(void)
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{
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if (conf_this_scope->soft_scopes < 0xfe)
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conf_this_scope->soft_scopes++;
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else
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cf_push_scope(NULL);
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}
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/**
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* cf_pop_soft_scope - leave a soft scope
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*
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* Leave a soft scope entered by cf_push_soft_scope().
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*/
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void
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cf_pop_soft_scope(void)
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{
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if (conf_this_scope->soft_scopes)
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conf_this_scope->soft_scopes--;
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else
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cf_pop_scope();
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}
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/**
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* cf_swap_soft_scope - convert soft scope to regular scope
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*
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* Soft scopes cannot hold symbols, so they must be converted to regular scopes
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* on first use. It is done automatically by cf_new_symbol().
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*/
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static inline void
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cf_swap_soft_scope(void)
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{
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if (conf_this_scope->soft_scopes)
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{
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conf_this_scope->soft_scopes--;
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cf_push_scope(NULL);
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}
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}
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/**
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* cf_symbol_class_name - get name of a symbol class
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* @sym: symbol
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@ -133,7 +133,8 @@ struct sym_scope {
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struct sym_scope *next; /* Next on scope stack */
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struct symbol *name; /* Name of this scope */
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uint slots; /* Variable slots */
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int active; /* Currently entered */
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byte active; /* Currently entered */
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byte soft_scopes; /* Number of soft scopes above */
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};
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struct bytestring {
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@ -190,6 +191,9 @@ struct symbol *cf_get_symbol(const byte *c);
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struct symbol *cf_default_name(char *template, int *counter);
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struct symbol *cf_localize_symbol(struct symbol *sym);
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static inline int cf_symbol_is_local(struct symbol *sym)
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{ return (sym->scope == conf_this_scope) && !conf_this_scope->soft_scopes; }
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/**
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* cf_define_symbol - define meaning of a symbol
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* @sym: symbol to be defined
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@ -213,6 +217,9 @@ struct symbol *cf_localize_symbol(struct symbol *sym);
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void cf_push_scope(struct symbol *);
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void cf_pop_scope(void);
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void cf_push_soft_scope(void);
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void cf_pop_soft_scope(void);
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char *cf_symbol_class_name(struct symbol *sym);
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/* Parser */
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@ -116,7 +116,7 @@ add_num_const(char *name, int val, const char *file, const uint line)
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struct f_val *v = cfg_alloc(sizeof(struct f_val));
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*v = (struct f_val) { .type = T_INT, .val.i = val };
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struct symbol *sym = cf_get_symbol(name);
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if (sym->class && (sym->scope == conf_this_scope))
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if (sym->class && cf_symbol_is_local(sym))
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cf_error("Error reading value for %s from %s:%d: already defined", name, file, line);
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cf_define_symbol(sym, SYM_CONSTANT | T_INT, val, v);
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