Class: Ruby2CExtension::Plugins::IVarCache

Inherits:
Ruby2CExtension::Plugin show all
Includes:
Util
Defined in:
lib/ruby2cext/plugins/ivar_cache.rb

Instance Attribute Summary

Attributes inherited from Ruby2CExtension::Plugin

#compiler

Instance Method Summary collapse

Methods included from Util

#args_arity, #deduce_type, #split_args, #values

Constructor Details

#initialize(compiler) ⇒ IVarCache

Returns a new instance of IVarCache.



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# File 'lib/ruby2cext/plugins/ivar_cache.rb', line 12

def initialize(compiler)
    super(compiler)
    @cache_index = Hash.new { |h,k| h[k] = h.size }
    compiler.add_preprocessor(:ivar) { |cfun, node|
        hash = node.last
        vid = hash[:vid]
        key = [vid, cfun.__id__]
        index = @cache_index[key]
        entry = "ivar_cache[#{index}]"
        "cache_ivar_get(&#{entry}, #{cfun.get_self}, #{cfun.sym(vid)})"
    }
    compiler.add_preprocessor(:iasgn) { |cfun, node|
        hash = node.last
        vid = hash[:vid]
        key = [vid, cfun.__id__]
        index = @cache_index[key]
        entry = "ivar_cache[#{index}]"
        "cache_ivar_set(&#{entry}, #{cfun.get_self}, #{cfun.sym(vid)}, #{cfun.comp(hash[:value])})"
    }
end

Instance Method Details

#global_c_code ⇒ Object 



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# File 'lib/ruby2cext/plugins/ivar_cache.rb', line 33

def global_c_code
    code = %{
        typedef struct {
            unsigned num_bins;
            unsigned bin_pos;
        } ivar_cache_entry;
        static ivar_cache_entry ivar_cache[#{@cache_index.size}];
        static void init_ivar_cache() {
            ivar_cache_entry* entry;
            for (entry = &ivar_cache[#{@cache_index.size-1}]; entry >= ivar_cache; --entry) {
                entry->num_bins = 0;
                entry->bin_pos = 0;
            }
        }
        typedef struct st_table_entry st_table_entry;
        struct st_table_entry {
            unsigned int hash;
            st_data_t key;
            st_data_t record;
            st_table_entry *next;
        };
        static st_table_entry *st_find_collided(st_table_entry **prev, ID id) {
            st_table_entry *cur = *prev;
            while (cur = cur->next) {
                if (cur->hash == id) {
                    (*prev)->next = cur->next;
                    cur->next = *prev;
                    *prev = cur;
                    return cur;
                }
                prev = &(*prev)->next;
            }
            return 0;
        }
        static VALUE cache_ivar_get(ivar_cache_entry* entry,
                                           VALUE obj, ID id)
        {
            st_table* table = ROBJECT(obj)->iv_tbl;
            unsigned bin_pos;
            st_table_entry *cur;
            switch (TYPE(obj)) {
                case T_OBJECT:
                case T_CLASS:
                case T_MODULE:
                    break;
                default:
                    return rb_ivar_get(obj, id);
            }
            if (!table) return Qnil;
            if (entry->num_bins==table->num_bins) {
                bin_pos = entry->bin_pos;
            } else {
                entry->num_bins = table->num_bins;
                bin_pos = entry->bin_pos = id % table->num_bins;
            }
            cur = table->bins[bin_pos];
            if (!cur) return Qnil;
            if (cur->hash == id) return cur->record;
            cur = st_find_collided(&table->bins[bin_pos], id);
            return cur ? cur->record : Qnil;
        }
        static VALUE cache_ivar_set(ivar_cache_entry* entry,
                                           VALUE obj, ID id, VALUE val)
        {
            st_table* table;
            unsigned bin_pos;
            st_table_entry *cur;
            if (!OBJ_TAINTED(obj) && rb_safe_level() >= 4 || OBJ_FROZEN(obj))
                return rb_ivar_set(obj, id, val);
            switch (TYPE(obj)) {
                case T_OBJECT:
                case T_CLASS:
                case T_MODULE:
                    break;
                default:
                    return rb_ivar_set(obj, id, val);
            }
            table = ROBJECT(obj)->iv_tbl;
            if (!table) {
                table = ROBJECT(obj)->iv_tbl = st_init_numtable();
            }
            if (entry->num_bins==table->num_bins) {
                bin_pos = entry->bin_pos;
            } else {
                entry->num_bins = table->num_bins;
                bin_pos = entry->bin_pos = id % table->num_bins;
            }
            cur = table->bins[bin_pos];
            if (!cur) {
                st_add_direct(table, id, val);
                return val;
            }
            if (cur->hash == id) return (cur->record = val);
            cur = st_find_collided(&table->bins[bin_pos], id);
            if (cur) {
                return (cur->record = val);
            } else {
                st_add_direct(table, id, val);
                return val;
            }
        }
    }
    code
end

#init_c_code ⇒ Object 



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# File 'lib/ruby2cext/plugins/ivar_cache.rb', line 138

def init_c_code
    %{
        init_ivar_cache();
    }
end