From 9bc5cf08440188fa3dab1115f10a0859ee2c7252 Mon Sep 17 00:00:00 2001 From: whitequark Date: Fri, 4 Jan 2019 04:54:20 +0000 Subject: [PATCH] flowmap: cleanup for clarity. NFCI. --- passes/techmap/flowmap.cc | 248 ++++++++++++++++++++--------------- passes/tests/flowmap/flow.v | 22 ++++ passes/tests/flowmap/flowp.v | 16 +++ 3 files changed, 179 insertions(+), 107 deletions(-) create mode 100644 passes/tests/flowmap/flow.v create mode 100644 passes/tests/flowmap/flowp.v diff --git a/passes/techmap/flowmap.cc b/passes/techmap/flowmap.cc index 5d6b8b645..1b53de4db 100644 --- a/passes/techmap/flowmap.cc +++ b/passes/techmap/flowmap.cc @@ -402,29 +402,34 @@ struct FlowGraph struct FlowmapWorker { int order; - pool cell_types; bool debug; RTLIL::Module *module; SigMap sigmap; ModIndex index; - pool cells; + + dict node_origins; pool nodes, inputs, outputs; dict> edges_fw, edges_bw; dict labels; - dict> lut_gates, lut_inputs; + pool lut_nodes; + dict> lut_gates; + dict> lut_edges_fw, lut_edges_bw; - dict node_origins; - dict> cell_fanout; + int gate_count = 0, lut_count = 0, packed_count = 0; + int gate_area = 0, lut_area = 0; - int mapped_count = 0, packed_count = 0, unique_packed_count = 0; + enum class GraphMode { + Label, + Cut, + }; - void dump_dot_graph(string filename, + void dump_dot_graph(string filename, GraphMode mode, pool subgraph_nodes = {}, dict> subgraph_edges = {}, - pair, pool> cut = {}, - dict> collapsed = {}) + dict> collapsed = {}, + pair, pool> cut = {}) { if (subgraph_nodes.empty()) subgraph_nodes = nodes; @@ -436,26 +441,29 @@ struct FlowmapWorker for (auto collapsed_node : collapsed[node]) if (collapsed_node != node) label += stringf(" %s", log_signal(collapsed_node)); - if (labels[node] == -1) - label += "\nl=?"; - else - label += stringf("\nl=%d", labels[node]); - if (cut.first.empty() && cut.second.empty()) + switch (mode) { - if (labels[node] == -1) + case GraphMode::Label: + if (labels[node] == -1) + { + label += "\nl=?"; + return GraphStyle{label}; + } + else + { + label += stringf("\nl=%d", labels[node]); + string fillcolor = stringf("/set311/%d", 1 + labels[node] % 11); + return GraphStyle{label, "", fillcolor}; + } + + case GraphMode::Cut: + if (cut.first[node]) + return GraphStyle{label, "blue"}; + if (cut.second[node]) + return GraphStyle{label, "red"}; return GraphStyle{label}; - string fillcolor = stringf("/set311/%d", 1 + labels[node] % 11); - return GraphStyle{label, "", fillcolor}; - } - else - { - string color = "black"; - if (cut.first[node]) - color = "blue"; - if (cut.second[node]) - color = "red"; - return GraphStyle{label, color}; } + return GraphStyle{label}; }; auto edge_style = [&](RTLIL::SigBit, RTLIL::SigBit) { return GraphStyle{}; @@ -519,57 +527,56 @@ struct FlowmapWorker return flow_graph; } - FlowmapWorker(int order, pool cell_types, bool debug, RTLIL::Module *module) : - order(order), cell_types(cell_types), debug(debug), module(module), sigmap(module), index(module) + void discover_nodes(pool cell_types) { - log("Labeling cells.\n"); for (auto cell : module->selected_cells()) { - if (cell_types[cell->type]) + if (!cell_types[cell->type]) + continue; + + if (!cell->known()) + log_error("Cell %s (%s.%s) is unknown.\n", cell->type.c_str(), log_id(module), log_id(cell)); + + pool fanout; + for (auto conn : cell->connections()) { - if (!cell->known()) + if (!cell->output(conn.first)) continue; + int offset = -1; + for (auto bit : conn.second) { - log_error("Cell %s (%s.%s) is unknown.\n", cell->type.c_str(), log_id(module), log_id(cell)); + offset++; + if (!bit.wire) continue; + auto mapped_bit = sigmap(bit); + if (nodes[mapped_bit]) + log_error("Multiple drivers found for wire %s.\n", log_signal(mapped_bit)); + nodes.insert(mapped_bit); + node_origins[mapped_bit] = ModIndex::PortInfo(cell, conn.first, offset); + fanout.insert(mapped_bit); } - cells.insert(cell); + } - for (auto conn : cell->connections()) + int fanin = 0; + for (auto conn : cell->connections()) + { + if (!cell->input(conn.first)) continue; + for (auto bit : sigmap(conn.second)) { - if (!cell->output(conn.first)) continue; - int offset = -1; - for (auto bit : conn.second) + if (!bit.wire) continue; + for (auto fanout_bit : fanout) { - offset++; - if (!bit.wire) continue; - auto mapped_bit = sigmap(bit); - if (nodes[mapped_bit]) - log_error("Multiple drivers found for wire %s.\n", log_signal(mapped_bit)); - nodes.insert(mapped_bit); - node_origins[mapped_bit] = ModIndex::PortInfo(cell, conn.first, offset); - cell_fanout[cell].insert(mapped_bit); + edges_fw[bit].insert(fanout_bit); + edges_bw[fanout_bit].insert(bit); } + fanin++; } + } - int fanin = 0; - for (auto conn : cell->connections()) - { - if (!cell->input(conn.first)) continue; - for (auto bit : sigmap(conn.second)) - { - if (!bit.wire) continue; - for (auto fanout_bit : cell_fanout[cell]) - { - edges_fw[bit].insert(fanout_bit); - edges_bw[fanout_bit].insert(bit); - } - fanin++; - } - } + if (fanin > order) + log_error("Cell %s (%s.%s) with fan-in %d cannot be mapped to a %d-LUT.\n", + cell->type.c_str(), log_id(module), log_id(cell), fanin, order); - if (fanin > order) - log_error("Cell %s (%s.%s) with fan-in %d cannot be mapped to a %d-LUT.\n", - cell->type.c_str(), log_id(module), log_id(cell), fanin, order); - } + gate_count++; + gate_area += 1 << fanin; } for (auto edge : edges_fw) @@ -591,15 +598,23 @@ struct FlowmapWorker outputs.insert(node); } + if (debug) + { + dump_dot_graph("flowmap-initial.dot", GraphMode::Label); + log("Dumped initial graph to `flowmap-initial.dot`.\n"); + } + } + + void label_nodes() + { for (auto node : nodes) labels[node] = -1; for (auto input : inputs) - labels[input] = 0; - - if (debug) { - dump_dot_graph("flowmap-initial.dot"); - log("Dumped complete initial graph to `flowmap-initial.dot`.\n"); + if (input.wire->attributes.count("\\$flowmap_level")) + labels[input] = input.wire->attributes["\\$flowmap_level"].as_int(); + else + labels[input] = 0; } pool worklist = nodes; @@ -661,70 +676,73 @@ struct FlowmapWorker k.insert(xi_node_pred); } log_assert((int)k.size() <= order); - lut_inputs[sink] = k; + lut_edges_bw[sink] = k; + for (auto k_node : k) + lut_edges_fw[k_node].insert(sink); if (debug) { log(" Maximum flow: %d. Assigned label %d.\n", flow, labels[sink]); - dump_dot_graph(stringf("flowmap-%d-sub.dot", debug_num), subgraph, {}, {x, xi}); + dump_dot_graph(stringf("flowmap-%d-sub.dot", debug_num), GraphMode::Cut, subgraph, {}, {}, {x, xi}); log(" Dumped subgraph to `flowmap-%d-sub.dot`.\n", debug_num); flow_graph.dump_dot_graph(stringf("flowmap-%d-flow.dot", debug_num)); log(" Dumped flow graph to `flowmap-%d-flow.dot`.\n", debug_num); - log(" LUT packed:"); - for (auto xi_node : xi) - log(" %s", log_signal(xi_node)); - log(".\n"); log(" LUT inputs:"); for (auto k_node : k) log(" %s", log_signal(k_node)); log(".\n"); + log(" LUT packed gates:"); + for (auto xi_node : xi) + log(" %s", log_signal(xi_node)); + log(".\n"); } for (auto sink_succ : edges_fw[sink]) worklist.insert(sink_succ); } - int depth = 0; - for (auto label : labels) - depth = max(depth, label.second); - log("Maximum depth: %d levels.\n", depth); - if (debug) { - dump_dot_graph("flowmap-labeled.dot"); - log("Dumped complete labeled graph to `flowmap-labeled.dot`.\n"); + dump_dot_graph("flowmap-labeled.dot", GraphMode::Label); + log("Dumped labeled graph to `flowmap-labeled.dot`.\n"); } + } - pool lut_nodes; - dict> lut_edges; - worklist = outputs; + int pack_luts() + { + pool worklist = outputs; while (!worklist.empty()) { auto lut_node = worklist.pop(); lut_nodes.insert(lut_node); - for (auto input_node : lut_inputs[lut_node]) - { - lut_edges[input_node].insert(lut_node); + for (auto input_node : lut_edges_bw[lut_node]) if (!lut_nodes[input_node] && !inputs[input_node]) worklist.insert(input_node); - } } + int depth = 0; + for (auto label : labels) + depth = max(depth, label.second); + log("Solved to %d LUTs in %d levels.\n", (int)lut_nodes.size(), depth); + if (debug) { - pool lut_and_input_nodes = lut_nodes; + pool lut_and_input_nodes; + lut_and_input_nodes.insert(lut_nodes.begin(), lut_nodes.end()); lut_and_input_nodes.insert(inputs.begin(), inputs.end()); - dump_dot_graph("flowmap-packed.dot", lut_and_input_nodes, lut_edges, {}, lut_gates); - log("Dumped complete packed graph to `flowmap-packed.dot`.\n"); + dump_dot_graph("flowmap-packed.dot", GraphMode::Label, lut_and_input_nodes, lut_edges_fw, lut_gates); + log("Dumped packed graph to `flowmap-packed.dot`.\n"); } + return depth; + } + + void map_cells() + { ConstEval ce(module); for (auto input_node : inputs) ce.stop(input_node); - log("\n"); - log("Mapping cells.\n"); - pool mapped_nodes; for (auto node : lut_nodes) { @@ -759,7 +777,7 @@ struct FlowmapWorker log_id(module), log_id(gate_origin.cell), gate_origin.port.c_str(), gate_origin.offset, log_signal(gate_node)); } - vector input_nodes(lut_inputs[node].begin(), lut_inputs[node].end()); + vector input_nodes(lut_edges_bw[node].begin(), lut_edges_bw[node].end()); RTLIL::Const lut_table(State::Sx, 1 << input_nodes.size()); for (unsigned i = 0; i < (1 << input_nodes.size()); i++) { @@ -786,7 +804,6 @@ struct FlowmapWorker lut_a.append_bit(input_node); RTLIL::Cell *lut = module->addLut(NEW_ID, lut_a, lut_y, lut_table); - mapped_count++; mapped_nodes.insert(node); for (auto gate_node : lut_gates[node]) { @@ -794,11 +811,11 @@ struct FlowmapWorker lut->add_strpool_attribute("\\src", gate_origin.cell->get_strpool_attribute("\\src")); packed_count++; } + lut_count++; + lut_area += 1 << input_nodes.size(); log(" Packed into a %d-LUT %s.%s.\n", (int)input_nodes.size(), log_id(module), log_id(lut)); } - unique_packed_count += nodes.size(); - for (auto node : mapped_nodes) { auto origin = node_origins[node]; @@ -807,6 +824,19 @@ struct FlowmapWorker origin.cell->setPort(origin.port, driver); } } + + FlowmapWorker(int order, pool cell_types, bool debug, RTLIL::Module *module) : + order(order), debug(debug), module(module), sigmap(module), index(module) + { + log("Labeling cells.\n"); + discover_nodes(cell_types); + label_nodes(); + pack_luts(); + + log("\n"); + log("Mapping cells.\n"); + map_cells(); + } }; static void split(std::vector &tokens, const std::string &text, char sep) @@ -832,7 +862,7 @@ struct FlowmapPass : public Pass { log("be evaluated with the `eval` pass, including cells with multiple output ports\n"); log("and multi-bit input and output ports.\n"); log("\n"); - log(" -maxlut \n"); + log(" -maxlut k\n"); log(" perform technology mapping for a k-LUT architecture. if not specified,\n"); log(" defaults to 3.\n"); log("\n"); @@ -846,8 +876,6 @@ struct FlowmapPass : public Pass { } void execute(std::vector args, RTLIL::Design *design) YS_OVERRIDE { - log_header(design, "Executing FLOWMAP pass (pack LUTs with FlowMap).\n"); - int order = 3; vector cells; bool debug = false; @@ -885,18 +913,24 @@ struct FlowmapPass : public Pass { cell_types = {"$_NOT_", "$_AND_", "$_OR_", "$_XOR_", "$_MUX_"}; } - int mapped_count = 0, packed_count = 0, unique_packed_count = 0; + log_header(design, "Executing FLOWMAP pass (pack LUTs with FlowMap).\n"); + + int gate_count = 0, lut_count = 0, packed_count = 0; + int gate_area = 0, lut_area = 0; for (auto module : design->selected_modules()) { FlowmapWorker worker(order, cell_types, debug, module); - mapped_count += worker.mapped_count; + gate_count += worker.gate_count; + lut_count += worker.lut_count; packed_count += worker.packed_count; - unique_packed_count += worker.unique_packed_count; + gate_area += worker.gate_area; + lut_area += worker.lut_area; } log("\n"); - log("Mapped %d LUTs.\n", mapped_count); - log("Packed %d cells %d times.\n", unique_packed_count, packed_count); + log("Mapped %d LUTs.\n", lut_count); + log("Packed %d cells; duplicated %d cells.\n", packed_count, packed_count - gate_count); + log("Solution has %.1f%% area overhead.\n", (lut_area - gate_area) * 100.0 / gate_area); } } FlowmapPass; diff --git a/passes/tests/flowmap/flow.v b/passes/tests/flowmap/flow.v new file mode 100644 index 000000000..297ef910e --- /dev/null +++ b/passes/tests/flowmap/flow.v @@ -0,0 +1,22 @@ +// Exact reproduction of Figure 2(a) from 10.1109/43.273754. +module top(...); + input a,b,c,d,e,f; + wire nA = b&c; + wire A = !nA; + wire nB = c|d; + wire B = !nB; + wire nC = e&f; + wire C = !nC; + wire D = A|B; + wire E = a&D; + wire nF = D&C; + wire F = !nF; + wire nG = F|B; + wire G = !nG; + wire H = a&F; + wire I = E|G; + wire J = G&C; + wire np = H&I; + output p = !np; + output q = A|J; +endmodule diff --git a/passes/tests/flowmap/flowp.v b/passes/tests/flowmap/flowp.v new file mode 100644 index 000000000..2fb40ffa4 --- /dev/null +++ b/passes/tests/flowmap/flowp.v @@ -0,0 +1,16 @@ +// Like flow.v, but results in a network identical to Figure 2(b). +module top(...); + input a,b,c,d,e,f; + wire A = b&c; + wire B = c|d; + wire C = e&f; + wire D = A|B; + wire E = a&D; + wire F = D&C; + wire G = F|B; + wire H = a&F; + wire I = E|G; + wire J = G&C; + output p = H&I; + output q = A|J; +endmodule -- 2.30.2