flatten: simplify.

`flatten` cannot derive modules in most cases because that would just
yield processes, and it does not support `-autoproc`; in practice
`flatten` has to be preceded by a call to `hierarchy`, which makes
deriving unnecessary.

diff --git a/passes/techmap/flatten.cc b/passes/techmap/flatten.cc
index 75345fcc1096d770c0cacbbb573ead56b4304779..c4054141d724f85ac01d26754bbac1954a5e5960 100644 (file)
--- a/passes/techmap/flatten.cc
+++ b/passes/techmap/flatten.cc
@@ -51,15 +51,13 @@ void apply_prefix(IdString prefix, RTLIL::SigSpec &sig, RTLIL::Module *module)
 
 struct FlattenWorker
 {
-       dict<std::pair<IdString, dict<IdString, RTLIL::Const>>, RTLIL::Module*> cache;
-
        pool<IdString> flatten_do_list;
        pool<IdString> flatten_done_list;
        pool<Cell*> flatten_keep_list;
 
        bool ignore_wb = false;
 
-       void flatten_module(RTLIL::Design *design, RTLIL::Module *module, RTLIL::Cell *cell, RTLIL::Module *tpl)
+       void flatten_cell(RTLIL::Design *design, RTLIL::Module *module, RTLIL::Cell *cell, RTLIL::Module *tpl)
        {
                if (tpl->processes.size() != 0) {
                        log("Flattening yielded processes:");
@@ -252,64 +250,30 @@ struct FlattenWorker
                if (!design->selected(module) || module->get_blackbox_attribute(ignore_wb))
                        return false;
 
-               bool log_continue = false;
                bool did_something = false;
-               LogMakeDebugHdl mkdebug;
 
                for (auto cell : module->selected_cells())
                {
                        if (!design->has(cell->type))
                                continue;
 
-                       if (cell->get_bool_attribute(ID::keep_hierarchy) || design->module(cell->type)->get_bool_attribute(ID::keep_hierarchy)) {
-                               if (!flatten_keep_list[cell]) {
-                                       log("Keeping %s.%s (found keep_hierarchy property).\n", log_id(module), log_id(cell));
-                                       flatten_keep_list.insert(cell);
-                               }
-                               if (!flatten_done_list[cell->type])
-                                       flatten_do_list.insert(cell->type);
-                               continue;
-                       }
-
                        RTLIL::Module *tpl = design->module(cell->type);
-                       dict<IdString, RTLIL::Const> parameters(cell->parameters);
-
                        if (tpl->get_blackbox_attribute(ignore_wb))
                                continue;
 
-                       std::pair<IdString, dict<IdString, RTLIL::Const>> key(cell->type, parameters);
-                       IdString derived_name;
-                       auto it = cache.find(key);
-                       if (it != cache.end()) {
-                               derived_name = cell->type;
-                               tpl = it->second;
-                       } else {
-                               if (parameters.size() != 0) {
-                                       mkdebug.on();
-                                       derived_name = tpl->derive(design, parameters);
-                                       tpl = design->module(derived_name);
-                                       log_continue = true;
+                       if (cell->get_bool_attribute(ID::keep_hierarchy) || tpl->get_bool_attribute(ID::keep_hierarchy)) {
+                               if (!flatten_keep_list[cell]) {
+                                       log("Keeping %s.%s (found keep_hierarchy property).\n", log_id(module), log_id(cell));
+                                       flatten_keep_list.insert(cell);
                                }
-                               cache.emplace(std::move(key), tpl);
-                       }
-
-                       if (log_continue) {
-                               log_header(design, "Continuing FLATTEN pass.\n");
-                               log_continue = false;
-                               mkdebug.off();
+                               continue;
                        }
 
                        log_debug("Flattening %s.%s (%s) using %s.\n", log_id(module), log_id(cell), log_id(cell->type), log_id(tpl));
-                       flatten_module(design, module, cell, tpl);
+                       flatten_cell(design, module, cell, tpl);
                        did_something = true;
                }
 
-               if (log_continue) {
-                       log_header(design, "Continuing FLATTEN pass.\n");
-                       log_continue = false;
-                       mkdebug.off();
-               }
-
                return did_something;
        }
 };