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Diffstat (limited to 'backends/cxxrtl/cxxrtl.cc')
| -rw-r--r-- | backends/cxxrtl/cxxrtl.cc | 1688 |
1 files changed, 1688 insertions, 0 deletions
diff --git a/backends/cxxrtl/cxxrtl.cc b/backends/cxxrtl/cxxrtl.cc new file mode 100644 index 000000000..465882858 --- /dev/null +++ b/backends/cxxrtl/cxxrtl.cc @@ -0,0 +1,1688 @@ +/* + * yosys -- Yosys Open SYnthesis Suite + * + * Copyright (C) 2019-2020 whitequark <whitequark@whitequark.org> + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + */ + +#include "kernel/rtlil.h" +#include "kernel/register.h" +#include "kernel/sigtools.h" +#include "kernel/utils.h" +#include "kernel/celltypes.h" +#include "kernel/log.h" + +USING_YOSYS_NAMESPACE +PRIVATE_NAMESPACE_BEGIN + +// [[CITE]] +// Peter Eades; Xuemin Lin; W. F. Smyth, "A Fast Effective Heuristic For The Feedback Arc Set Problem" +// Information Processing Letters, Vol. 47, pp 319-323, 1993 +// https://pdfs.semanticscholar.org/c7ed/d9acce96ca357876540e19664eb9d976637f.pdf + +// A topological sort (on a cell/wire graph) is always possible in a fully flattened RTLIL design without +// processes or logic loops where every wire has a single driver. Logic loops are illegal in RTLIL and wires +// with multiple drivers can be split by the `splitnets` pass; however, interdependencies between processes +// or module instances can create strongly connected components without introducing evaluation nondeterminism. +// We wish to support designs with such benign SCCs (as well as designs with multiple drivers per wire), so +// we sort the graph in a way that minimizes feedback arcs. If there are no feedback arcs in the sorted graph, +// then a more efficient evaluation method is possible, since eval() will always immediately converge. +template<class T> +struct Scheduler { + struct Vertex { + T *data; + Vertex *prev, *next; + pool<Vertex*, hash_ptr_ops> preds, succs; + + Vertex() : data(NULL), prev(this), next(this) {} + Vertex(T *data) : data(data), prev(NULL), next(NULL) {} + + bool empty() const + { + log_assert(data == NULL); + if (next == this) { + log_assert(prev == next); + return true; + } + return false; + } + + void link(Vertex *list) + { + log_assert(prev == NULL && next == NULL); + next = list; + prev = list->prev; + list->prev->next = this; + list->prev = this; + } + + void unlink() + { + log_assert(prev->next == this && next->prev == this); + prev->next = next; + next->prev = prev; + next = prev = NULL; + } + + int delta() const + { + return succs.size() - preds.size(); + } + }; + + std::vector<Vertex*> vertices; + Vertex *sources = new Vertex; + Vertex *sinks = new Vertex; + dict<int, Vertex*> bins; + + ~Scheduler() + { + delete sources; + delete sinks; + for (auto bin : bins) + delete bin.second; + for (auto vertex : vertices) + delete vertex; + } + + Vertex *add(T *data) + { + Vertex *vertex = new Vertex(data); + vertices.push_back(vertex); + return vertex; + } + + void relink(Vertex *vertex) + { + if (vertex->succs.empty()) + vertex->link(sinks); + else if (vertex->preds.empty()) + vertex->link(sources); + else { + int delta = vertex->delta(); + if (!bins.count(delta)) + bins[delta] = new Vertex; + vertex->link(bins[delta]); + } + } + + Vertex *remove(Vertex *vertex) + { + vertex->unlink(); + for (auto pred : vertex->preds) { + if (pred == vertex) + continue; + log_assert(pred->succs[vertex]); + pred->unlink(); + pred->succs.erase(vertex); + relink(pred); + } + for (auto succ : vertex->succs) { + if (succ == vertex) + continue; + log_assert(succ->preds[vertex]); + succ->unlink(); + succ->preds.erase(vertex); + relink(succ); + } + vertex->preds.clear(); + vertex->succs.clear(); + return vertex; + } + + std::vector<Vertex*> schedule() + { + std::vector<Vertex*> s1, s2r; + for (auto vertex : vertices) + relink(vertex); + bool bins_empty = false; + while (!(sinks->empty() && sources->empty() && bins_empty)) { + while (!sinks->empty()) + s2r.push_back(remove(sinks->next)); + while (!sources->empty()) + s1.push_back(remove(sources->next)); + // Choosing u in this implementation isn't O(1), but the paper handwaves which data structure they suggest + // using to get O(1) relinking *and* find-max-key ("it is clear"... no it isn't), so this code uses a very + // naive implementation of find-max-key. + bins_empty = true; + bins.template sort<std::greater<int>>(); + for (auto bin : bins) { + if (!bin.second->empty()) { + bins_empty = false; + s1.push_back(remove(bin.second->next)); + break; + } + } + } + s1.insert(s1.end(), s2r.rbegin(), s2r.rend()); + return s1; + } +}; + +static bool is_unary_cell(RTLIL::IdString type) +{ + return type.in( + ID($not), ID($logic_not), ID($reduce_and), ID($reduce_or), ID($reduce_xor), ID($reduce_xnor), ID($reduce_bool), + ID($pos), ID($neg)); +} + +static bool is_binary_cell(RTLIL::IdString type) +{ + return type.in( + ID($and), ID($or), ID($xor), ID($xnor), ID($logic_and), ID($logic_or), + ID($shl), ID($sshl), ID($shr), ID($sshr), ID($shift), ID($shiftx), + ID($eq), ID($ne), ID($eqx), ID($nex), ID($gt), ID($ge), ID($lt), ID($le), + ID($add), ID($sub), ID($mul), ID($div), ID($mod)); +} + +static bool is_elidable_cell(RTLIL::IdString type) +{ + return is_unary_cell(type) || is_binary_cell(type) || type.in( + ID($mux), ID($concat), ID($slice)); +} + +static bool is_sync_ff_cell(RTLIL::IdString type) +{ + return type.in( + ID($dff), ID($dffe)); +} + +static bool is_ff_cell(RTLIL::IdString type) +{ + return is_sync_ff_cell(type) || type.in( + ID($adff), ID($dffsr), ID($dlatch), ID($dlatchsr), ID($sr)); +} + +static bool is_internal_cell(RTLIL::IdString type) +{ + return type[0] == '$' && !type.begins_with("$paramod\\"); +} + +struct FlowGraph { + struct Node { + enum class Type { + CONNECT, + CELL, + PROCESS + }; + + Type type; + RTLIL::SigSig connect = {}; + const RTLIL::Cell *cell = NULL; + const RTLIL::Process *process = NULL; + }; + + std::vector<Node*> nodes; + dict<const RTLIL::Wire*, pool<Node*, hash_ptr_ops>> wire_defs, wire_uses; + dict<const RTLIL::Wire*, bool> wire_def_elidable, wire_use_elidable; + + ~FlowGraph() + { + for (auto node : nodes) + delete node; + } + + void add_defs(Node *node, const RTLIL::SigSpec &sig, bool elidable) + { + for (auto chunk : sig.chunks()) + if (chunk.wire) + wire_defs[chunk.wire].insert(node); + // Only defs of an entire wire in the right order can be elided. + if (sig.is_wire()) + wire_def_elidable[sig.as_wire()] = elidable; + } + + void add_uses(Node *node, const RTLIL::SigSpec &sig) + { + for (auto chunk : sig.chunks()) + if (chunk.wire) { + wire_uses[chunk.wire].insert(node); + // Only a single use of an entire wire in the right order can be elided. + // (But the use can include other chunks.) + if (!wire_use_elidable.count(chunk.wire)) + wire_use_elidable[chunk.wire] = true; + else + wire_use_elidable[chunk.wire] = false; + } + } + + bool is_elidable(const RTLIL::Wire *wire) const + { + if (wire_def_elidable.count(wire) && wire_use_elidable.count(wire)) + return wire_def_elidable.at(wire) && wire_use_elidable.at(wire); + return false; + } + + // Connections + void add_connect_defs_uses(Node *node, const RTLIL::SigSig &conn) + { + add_defs(node, conn.first, /*elidable=*/true); + add_uses(node, conn.second); + } + + Node *add_node(const RTLIL::SigSig &conn) + { + Node *node = new Node; + node->type = Node::Type::CONNECT; + node->connect = conn; + nodes.push_back(node); + add_connect_defs_uses(node, conn); + return node; + } + + // Cells + void add_cell_defs_uses(Node *node, const RTLIL::Cell *cell) + { + log_assert(cell->known()); + for (auto conn : cell->connections()) { + if (cell->output(conn.first)) { + if (is_sync_ff_cell(cell->type) || (cell->type == ID($memrd) && cell->getParam(ID(CLK_ENABLE)).as_bool())) + /* non-combinatorial outputs do not introduce defs */; + else if (is_elidable_cell(cell->type)) + add_defs(node, conn.second, /*elidable=*/true); + else if (is_internal_cell(cell->type)) + add_defs(node, conn.second, /*elidable=*/false); + else { + // Unlike outputs of internal cells (which generate code that depends on the ability to set the output + // wire bits), outputs of user cells are normal wires, and the wires connected to them can be elided. + add_defs(node, conn.second, /*elidable=*/true); + } + } + if (cell->input(conn.first)) + add_uses(node, conn.second); + } + } + + Node *add_node(const RTLIL::Cell *cell) + { + Node *node = new Node; + node->type = Node::Type::CELL; + node->cell = cell; + nodes.push_back(node); + add_cell_defs_uses(node, cell); + return node; + } + + // Processes + void add_case_defs_uses(Node *node, const RTLIL::CaseRule *case_) + { + for (auto &action : case_->actions) { + add_defs(node, action.first, /*elidable=*/false); + add_uses(node, action.second); + } + for (auto sub_switch : case_->switches) { + add_uses(node, sub_switch->signal); + for (auto sub_case : sub_switch->cases) { + for (auto &compare : sub_case->compare) + add_uses(node, compare); + add_case_defs_uses(node, sub_case); + } + } + } + + void add_process_defs_uses(Node *node, const RTLIL::Process *process) + { + add_case_defs_uses(node, &process->root_case); + for (auto sync : process->syncs) + for (auto action : sync->actions) { + if (sync->type == RTLIL::STp || sync->type == RTLIL::STn || sync->type == RTLIL::STe) + /* sync actions do not introduce feedback */; + else + add_defs(node, action.first, /*elidable=*/false); + add_uses(node, action.second); + } + } + + Node *add_node(const RTLIL::Process *process) + { + Node *node = new Node; + node->type = Node::Type::PROCESS; + node->process = process; + nodes.push_back(node); + add_process_defs_uses(node, process); + return node; + } +}; + +struct CxxrtlWorker { + bool elide_internal = false; + bool elide_public = false; + bool localize_internal = false; + bool localize_public = false; + bool run_splitnets = false; + + std::ostream &f; + std::string indent; + int temporary = 0; + + dict<const RTLIL::Module*, SigMap> sigmaps; + pool<const RTLIL::Wire*> sync_wires; + dict<RTLIL::SigBit, RTLIL::SyncType> sync_types; + pool<const RTLIL::Memory*> writable_memories; + dict<const RTLIL::Cell*, pool<const RTLIL::Cell*>> transparent_for; + dict<const RTLIL::Cell*, dict<RTLIL::Wire*, RTLIL::IdString>> cell_wire_defs; + dict<const RTLIL::Wire*, FlowGraph::Node> elided_wires; + dict<const RTLIL::Module*, std::vector<FlowGraph::Node>> schedule; + pool<const RTLIL::Wire*> localized_wires; + + CxxrtlWorker(std::ostream &f) : f(f) {} + + void inc_indent() { + indent += "\t"; + } + void dec_indent() { + indent.resize(indent.size() - 1); + } + + // RTLIL allows any characters in names other than whitespace. This presents an issue for generating C++ code + // because C++ identifiers may be only alphanumeric, cannot clash with C++ keywords, and cannot clash with cxxrtl + // identifiers. This issue can be solved with a name mangling scheme. We choose a name mangling scheme that results + // in readable identifiers, does not depend on an up-to-date list of C++ keywords, and is easy to apply. Its rules: + // 1. All generated identifiers start with `_`. + // 1a. Generated identifiers for public names (beginning with `\`) start with `p_`. + // 1b. Generated identifiers for internal names (beginning with `$`) start with `i_`. + // 2. An underscore is escaped with another underscore, i.e. `__`. + // 3. Any other non-alnum character is escaped with underscores around its lowercase hex code, e.g. `@` as `_40_`. + std::string mangle_name(const RTLIL::IdString &name) + { + std::string mangled; + bool first = true; + for (char c : name.str()) { + if (first) { + first = false; + if (c == '\\') + mangled += "p_"; + else if (c == '$') + mangled += "i_"; + else + log_assert(false); + } else { + if (isalnum(c)) { + mangled += c; + } else if (c == '_') { + mangled += "__"; + } else { + char l = c & 0xf, h = (c >> 4) & 0xf; + mangled += '_'; + mangled += (h < 10 ? '0' + h : 'a' + h - 10); + mangled += (l < 10 ? '0' + l : 'a' + l - 10); + mangled += '_'; + } + } + } + return mangled; + } + + std::string mangle_module_name(const RTLIL::IdString &name) + { + // Class namespace. + return mangle_name(name); + } + + std::string mangle_memory_name(const RTLIL::IdString &name) + { + // Class member namespace. + return "memory_" + mangle_name(name); + } + + std::string mangle_cell_name(const RTLIL::IdString &name) + { + // Class member namespace. + return "cell_" + mangle_name(name); + } + + std::string mangle_wire_name(const RTLIL::IdString &name) + { + // Class member namespace. + return mangle_name(name); + } + + std::string mangle(const RTLIL::Module *module) + { + return mangle_module_name(module->name); + } + + std::string mangle(const RTLIL::Memory *memory) + { + return mangle_memory_name(memory->name); + } + + std::string mangle(const RTLIL::Cell *cell) + { + return mangle_cell_name(cell->name); + } + + std::string mangle(const RTLIL::Wire *wire) + { + return mangle_wire_name(wire->name); + } + + std::string mangle(RTLIL::SigBit sigbit) + { + log_assert(sigbit.wire != NULL); + if (sigbit.wire->width == 1) + return mangle(sigbit.wire); + return mangle(sigbit.wire) + "_" + std::to_string(sigbit.offset); + } + + std::string fresh_temporary() + { + return stringf("tmp_%d", temporary++); + } + + void dump_attrs(const RTLIL::AttrObject *object) + { + for (auto attr : object->attributes) { + f << indent << "// " << attr.first.str() << ": "; + if (attr.second.flags & RTLIL::CONST_FLAG_STRING) { + f << attr.second.decode_string(); + } else { + f << attr.second.as_int(/*is_signed=*/attr.second.flags & RTLIL::CONST_FLAG_SIGNED); + } + f << "\n"; + } + } + + void dump_const_init(const RTLIL::Const &data, int width, int offset = 0, bool fixed_width = false) + { + f << "{"; + while (width > 0) { + const int CHUNK_SIZE = 32; + uint32_t chunk = data.extract(offset, width > CHUNK_SIZE ? CHUNK_SIZE : width).as_int(); + if (fixed_width) + f << stringf("0x%08xu", chunk); + else + f << stringf("%#xu", chunk); + if (width > CHUNK_SIZE) + f << ','; + offset += CHUNK_SIZE; + width -= CHUNK_SIZE; + } + f << "}"; + } + + void dump_const_init(const RTLIL::Const &data) + { + dump_const_init(data, data.size()); + } + + void dump_const(const RTLIL::Const &data, int width, int offset = 0, bool fixed_width = false) + { + f << "value<" << width << ">"; + dump_const_init(data, width, offset, fixed_width); + } + + void dump_const(const RTLIL::Const &data) + { + dump_const(data, data.size()); + } + + bool dump_sigchunk(const RTLIL::SigChunk &chunk, bool is_lhs) + { + if (chunk.wire == NULL) { + dump_const(chunk.data, chunk.width, chunk.offset); + return false; + } else { + if (!is_lhs && elided_wires.count(chunk.wire)) { + const FlowGraph::Node &node = elided_wires[chunk.wire]; + switch (node.type) { + case FlowGraph::Node::Type::CONNECT: + dump_connect_elided(node.connect); + break; + case FlowGraph::Node::Type::CELL: + if (is_elidable_cell(node.cell->type)) { + dump_cell_elided(node.cell); + } else { + f << mangle(node.cell) << "." << mangle_wire_name(cell_wire_defs[node.cell][chunk.wire]) << ".curr"; + } + break; + default: + log_assert(false); + } + } else if (localized_wires[chunk.wire]) { + f << mangle(chunk.wire); + } else { + f << mangle(chunk.wire) << (is_lhs ? ".next" : ".curr"); + } + if (chunk.width == chunk.wire->width && chunk.offset == 0) + return false; + else if (chunk.width == 1) + f << ".slice<" << chunk.offset << ">()"; + else + f << ".slice<" << chunk.offset+chunk.width-1 << "," << chunk.offset << ">()"; + return true; + } + } + + bool dump_sigspec(const RTLIL::SigSpec &sig, bool is_lhs) + { + if (sig.empty()) { + f << "value<0>()"; + return false; + } else if (sig.is_chunk()) { + return dump_sigchunk(sig.as_chunk(), is_lhs); + } else { + dump_sigchunk(*sig.chunks().rbegin(), is_lhs); + for (auto it = sig.chunks().rbegin() + 1; it != sig.chunks().rend(); ++it) { + f << ".concat("; + dump_sigchunk(*it, is_lhs); + f << ")"; + } + return true; + } + } + + void dump_sigspec_lhs(const RTLIL::SigSpec &sig) + { + dump_sigspec(sig, /*is_lhs=*/true); + } + + void dump_sigspec_rhs(const RTLIL::SigSpec &sig) + { + // In the contexts where we want template argument deduction to occur for `template<size_t Bits> ... value<Bits>`, + // it is necessary to have the argument to already be a `value<N>`, since template argument deduction and implicit + // type conversion are mutually exclusive. In these contexts, we use dump_sigspec_rhs() to emit an explicit + // type conversion, but only if the expression needs it. + bool is_complex = dump_sigspec(sig, /*is_lhs=*/false); + if (is_complex) + f << ".val()"; + } + + void collect_sigspec_rhs(const RTLIL::SigSpec &sig, std::vector<RTLIL::IdString> &cells) + { + for (auto chunk : sig.chunks()) { + if (!chunk.wire || !elided_wires.count(chunk.wire)) + continue; + + const FlowGraph::Node &node = elided_wires[chunk.wire]; + switch (node.type) { + case FlowGraph::Node::Type::CONNECT: + collect_connect(node.connect, cells); + break; + case FlowGraph::Node::Type::CELL: + collect_cell(node.cell, cells); + break; + default: + log_assert(false); + } + } + } + + void dump_connect_elided(const RTLIL::SigSig &conn) + { + dump_sigspec_rhs(conn.second); + } + + bool is_connect_elided(const RTLIL::SigSig &conn) + { + return conn.first.is_wire() && elided_wires.count(conn.first.as_wire()); + } + + void collect_connect(const RTLIL::SigSig &conn, std::vector<RTLIL::IdString> &cells) + { + if (!is_connect_elided(conn)) + return; + + collect_sigspec_rhs(conn.second, cells); + } + + void dump_connect(const RTLIL::SigSig &conn) + { + if (is_connect_elided(conn)) + return; + + f << indent << "// connection\n"; + f << indent; + dump_sigspec_lhs(conn.first); + f << " = "; + dump_connect_elided(conn); + f << ";\n"; + } + + void dump_cell_elided(const RTLIL::Cell *cell) + { + // Unary cells + if (is_unary_cell(cell->type)) { + f << cell->type.substr(1) << '_' << + (cell->getParam(ID(A_SIGNED)).as_bool() ? 's' : 'u') << + "<" << cell->getParam(ID(Y_WIDTH)).as_int() << ">("; + dump_sigspec_rhs(cell->getPort(ID(A))); + f << ")"; + // Binary cells + } else if (is_binary_cell(cell->type)) { + f << cell->type.substr(1) << '_' << + (cell->getParam(ID(A_SIGNED)).as_bool() ? 's' : 'u') << + (cell->getParam(ID(B_SIGNED)).as_bool() ? 's' : 'u') << + "<" << cell->getParam(ID(Y_WIDTH)).as_int() << ">("; + dump_sigspec_rhs(cell->getPort(ID(A))); + f << ", "; + dump_sigspec_rhs(cell->getPort(ID(B))); + f << ")"; + // Muxes + } else if (cell->type == ID($mux)) { + f << "("; + dump_sigspec_rhs(cell->getPort(ID(S))); + f << " ? "; + dump_sigspec_rhs(cell->getPort(ID(B))); + f << " : "; + dump_sigspec_rhs(cell->getPort(ID(A))); + f << ")"; + // Concats + } else if (cell->type == ID($concat)) { + dump_sigspec_rhs(cell->getPort(ID(B))); + f << ".concat("; + dump_sigspec_rhs(cell->getPort(ID(A))); + f << ").val()"; + // Slices + } else if (cell->type == ID($slice)) { + dump_sigspec_rhs(cell->getPort(ID(A))); + f << ".slice<"; + f << cell->getParam(ID(OFFSET)).as_int() + cell->getParam(ID(Y_WIDTH)).as_int() - 1; + f << ","; + f << cell->getParam(ID(OFFSET)).as_int(); + f << ">().val()"; + } else { + log_assert(false); + } + } + + bool is_cell_elided(const RTLIL::Cell *cell) + { + return is_elidable_cell(cell->type) && cell->hasPort(ID(Y)) && cell->getPort(ID(Y)).is_wire() && + elided_wires.count(cell->getPort(ID(Y)).as_wire()); + } + + void collect_cell(const RTLIL::Cell *cell, std::vector<RTLIL::IdString> &cells) + { + if (!is_cell_elided(cell)) + return; + + cells.push_back(cell->name); + for (auto port : cell->connections()) + if (port.first != ID(Y)) + collect_sigspec_rhs(port.second, cells); + } + + void dump_cell(const RTLIL::Cell *cell) + { + if (is_cell_elided(cell)) + return; + if (cell->type == ID($meminit)) + return; // Handled elsewhere. + + std::vector<RTLIL::IdString> elided_cells; + if (is_elidable_cell(cell->type)) { + for (auto port : cell->connections()) + if (port.first != ID(Y)) + collect_sigspec_rhs(port.second, elided_cells); + } + if (elided_cells.empty()) { + dump_attrs(cell); + f << indent << "// cell " << cell->name.str() << "\n"; + } else { + f << indent << "// cells"; + for (auto elided_cell : elided_cells) + f << " " << elided_cell.str(); + f << "\n"; + } + + // Elidable cells + if (is_elidable_cell(cell->type)) { + f << indent; + dump_sigspec_lhs(cell->getPort(ID(Y))); + f << " = "; + dump_cell_elided(cell); + f << ";\n"; + // Parallel (one-hot) muxes + } else if (cell->type == ID($pmux)) { + int width = cell->getParam(ID(WIDTH)).as_int(); + int s_width = cell->getParam(ID(S_WIDTH)).as_int(); + bool first = true; + for (int part = 0; part < s_width; part++) { + f << (first ? indent : " else "); + first = false; + f << "if ("; + dump_sigspec_rhs(cell->getPort(ID(S)).extract(part)); + f << ") {\n"; + inc_indent(); + f << indent; + dump_sigspec_lhs(cell->getPort(ID(Y))); + f << " = "; + dump_sigspec_rhs(cell->getPort(ID(B)).extract(part * width, width)); + f << ";\n"; + dec_indent(); + f << indent << "}"; + } + f << " else {\n"; + inc_indent(); + f << indent; + dump_sigspec_lhs(cell->getPort(ID(Y))); + f << " = "; + dump_sigspec_rhs(cell->getPort(ID(A))); + f << ";\n"; + dec_indent(); + f << indent << "}\n"; + // Flip-flops + } else if (is_ff_cell(cell->type)) { + if (cell->hasPort(ID(CLK)) && cell->getPort(ID(CLK)).is_wire()) { + // Edge-sensitive logic + RTLIL::SigBit clk_bit = cell->getPort(ID(CLK))[0]; + clk_bit = sigmaps[clk_bit.wire->module](clk_bit); + f << indent << "if (" << (cell->getParam(ID(CLK_POLARITY)).as_bool() ? "posedge_" : "negedge_") + << mangle(clk_bit) << ") {\n"; + inc_indent(); + if (cell->type == ID($dffe)) { + f << indent << "if ("; + dump_sigspec_rhs(cell->getPort(ID(EN))); + f << " == value<1> {" << cell->getParam(ID(EN_POLARITY)).as_bool() << "u}) {\n"; + inc_indent(); + } + f << indent; + dump_sigspec_lhs(cell->getPort(ID(Q))); + f << " = "; + dump_sigspec_rhs(cell->getPort(ID(D))); + f << ";\n"; + if (cell->type == ID($dffe)) { + dec_indent(); + f << indent << "}\n"; + } + dec_indent(); + f << indent << "}\n"; + } else if (cell->hasPort(ID(EN))) { + // Level-sensitive logic + f << indent << "if ("; + dump_sigspec_rhs(cell->getPort(ID(EN))); + f << " == value<1> {" << cell->getParam(ID(EN_POLARITY)).as_bool() << "u}) {\n"; + inc_indent(); + f << indent; + dump_sigspec_lhs(cell->getPort(ID(Q))); + f << " = "; + dump_sigspec_rhs(cell->getPort(ID(D))); + f << ";\n"; + dec_indent(); + f << indent << "}\n"; + } + if (cell->hasPort(ID(ARST))) { + // Asynchronous reset (entire coarse cell at once) + f << indent << "if ("; + dump_sigspec_rhs(cell->getPort(ID(ARST))); + f << " == value<1> {" << cell->getParam(ID(ARST_POLARITY)).as_bool() << "u}) {\n"; + inc_indent(); + f << indent; + dump_sigspec_lhs(cell->getPort(ID(Q))); + f << " = "; + dump_const(cell->getParam(ID(ARST_VALUE))); + f << ";\n"; + dec_indent(); + f << indent << "}\n"; + } + if (cell->hasPort(ID(SET))) { + // Asynchronous set (for individual bits) + f << indent; + dump_sigspec_lhs(cell->getPort(ID(Q))); + f << " = "; + dump_sigspec_lhs(cell->getPort(ID(Q))); + f << ".update("; + dump_const(RTLIL::Const(RTLIL::S1, cell->getParam(ID(WIDTH)).as_int())); + f << ", "; + dump_sigspec_rhs(cell->getPort(ID(SET))); + f << (cell->getParam(ID(SET_POLARITY)).as_bool() ? "" : ".bit_not()") << ");\n"; + } + if (cell->hasPort(ID(CLR))) { + // Asynchronous clear (for individual bits; priority over set) + f << indent; + dump_sigspec_lhs(cell->getPort(ID(Q))); + f << " = "; + dump_sigspec_lhs(cell->getPort(ID(Q))); + f << ".update("; + dump_const(RTLIL::Const(RTLIL::S0, cell->getParam(ID(WIDTH)).as_int())); + f << ", "; + dump_sigspec_rhs(cell->getPort(ID(CLR))); + f << (cell->getParam(ID(CLR_POLARITY)).as_bool() ? "" : ".bit_not()") << ");\n"; + } + // Memory ports + } else if (cell->type.in(ID($memrd), ID($memwr))) { + if (cell->getParam(ID(CLK_ENABLE)).as_bool()) { + RTLIL::SigBit clk_bit = cell->getPort(ID(CLK))[0]; + clk_bit = sigmaps[clk_bit.wire->module](clk_bit); + f << indent << "if (" << (cell->getParam(ID(CLK_POLARITY)).as_bool() ? "posedge_" : "negedge_") + << mangle(clk_bit) << ") {\n"; + inc_indent(); + } + RTLIL::Memory *memory = cell->module->memories[cell->getParam(ID(MEMID)).decode_string()]; + std::string valid_index_temp = fresh_temporary(); + f << indent << "auto " << valid_index_temp << " = memory_index("; + dump_sigspec_rhs(cell->getPort(ID(ADDR))); + f << ", " << memory->start_offset << ", " << memory->size << ");\n"; + if (cell->type == ID($memrd)) { + if (!cell->getPort(ID(EN)).is_fully_ones()) { + f << indent << "if ("; + dump_sigspec_rhs(cell->getPort(ID(EN))); + f << ") {\n"; + inc_indent(); + } + // The generated code has two bounds checks; one in an assertion, and another that guards the read. + // This is done so that the code does not invoke undefined behavior under any conditions, but nevertheless + // loudly crashes if an illegal condition is encountered. The assert may be turned off with -NDEBUG not + // just for release builds, but also to make sure the simulator (which is presumably embedded in some + // larger program) will never crash the code that calls into it. + // + // If assertions are disabled, out of bounds reads are defined to return zero. + f << indent << "assert(" << valid_index_temp << ".valid && \"out of bounds read\");\n"; + f << indent << "if(" << valid_index_temp << ".valid) {\n"; + inc_indent(); + if (writable_memories[memory]) { + std::string addr_temp = fresh_temporary(); + f << indent << "const value<" << cell->getPort(ID(ADDR)).size() << "> &" << addr_temp << " = "; + dump_sigspec_rhs(cell->getPort(ID(ADDR))); + f << ";\n"; + std::string lhs_temp = fresh_temporary(); + f << indent << "value<" << memory->width << "> " << lhs_temp << " = " + << mangle(memory) << "[" << valid_index_temp << ".index];\n"; + std::vector<const RTLIL::Cell*> memwr_cells(transparent_for[cell].begin(), transparent_for[cell].end()); + std::sort(memwr_cells.begin(), memwr_cells.end(), + [](const RTLIL::Cell *a, const RTLIL::Cell *b) { + return a->getParam(ID(PRIORITY)).as_int() < b->getParam(ID(PRIORITY)).as_int(); + }); + for (auto memwr_cell : memwr_cells) { + f << indent << "if (" << addr_temp << " == "; + dump_sigspec_rhs(memwr_cell->getPort(ID(ADDR))); + f << ") {\n"; + inc_indent(); + f << indent << lhs_temp << " = " << lhs_temp; + f << ".update("; + dump_sigspec_rhs(memwr_cell->getPort(ID(DATA))); + f << ", "; + dump_sigspec_rhs(memwr_cell->getPort(ID(EN))); + f << ");\n"; + dec_indent(); + f << indent << "}\n"; + } + f << indent; + dump_sigspec_lhs(cell->getPort(ID(DATA))); + f << " = " << lhs_temp << ";\n"; + } else { + f << indent; + dump_sigspec_lhs(cell->getPort(ID(DATA))); + f << " = " << mangle(memory) << "[" << valid_index_temp << ".index];\n"; + } + dec_indent(); + f << indent << "} else {\n"; + inc_indent(); + f << indent; + dump_sigspec_lhs(cell->getPort(ID(DATA))); + f << " = value<" << memory->width << "> {};\n"; + dec_indent(); + f << indent << "}\n"; + if (!cell->getPort(ID(EN)).is_fully_ones()) { + dec_indent(); + f << indent << "}\n"; + } + } else /*if (cell->type == ID($memwr))*/ { + log_assert(writable_memories[memory]); + // See above for rationale of having both the assert and the condition. + // + // If assertions are disabled, out of bounds writes are defined to do nothing. + f << indent << "assert(" << valid_index_temp << ".valid && \"out of bounds write\");\n"; + f << indent << "if (" << valid_index_temp << ".valid) {\n"; + inc_indent(); + f << indent << mangle(memory) << ".update(" << valid_index_temp << ".index, "; + dump_sigspec_rhs(cell->getPort(ID(DATA))); + f << ", "; + dump_sigspec_rhs(cell->getPort(ID(EN))); + f << ", " << cell->getParam(ID(PRIORITY)).as_int() << ");\n"; + dec_indent(); + f << indent << "}\n"; + } + if (cell->getParam(ID(CLK_ENABLE)).as_bool()) { + dec_indent(); + f << indent << "}\n"; + } + // Internal cells + } else if (is_internal_cell(cell->type)) { + log_cmd_error("Unsupported internal cell `%s'.\n", cell->type.c_str()); + // User cells + } else { + log_assert(cell->known()); + for (auto conn : cell->connections()) + if (cell->input(conn.first)) { + f << indent << mangle(cell) << "." << mangle_wire_name(conn.first) << ".next = "; + dump_sigspec_rhs(conn.second); + f << ";\n"; + } + f << indent << mangle(cell) << ".eval();\n"; + for (auto conn : cell->connections()) { + if (conn.second.is_wire()) { + RTLIL::Wire *wire = conn.second.as_wire(); + if (elided_wires.count(wire) && cell_wire_defs[cell].count(wire)) + continue; + } + if (cell->output(conn.first)) { + f << indent; + dump_sigspec_lhs(conn.second); + f << " = " << mangle(cell) << "." << mangle_wire_name(conn.first) << ".curr;\n"; + } + } + } + } + + void dump_assign(const RTLIL::SigSig &sigsig) + { + f << indent; + dump_sigspec_lhs(sigsig.first); + f << " = "; + dump_sigspec_rhs(sigsig.second); + f << ";\n"; + } + + void dump_case_rule(const RTLIL::CaseRule *rule) + { + for (auto action : rule->actions) + dump_assign(action); + for (auto switch_ : rule->switches) + dump_switch_rule(switch_); + } + + void dump_switch_rule(const RTLIL::SwitchRule *rule) + { + // The switch attributes are printed before the switch condition is captured. + dump_attrs(rule); + std::string signal_temp = fresh_temporary(); + f << indent << "const value<" << rule->signal.size() << "> &" << signal_temp << " = "; + dump_sigspec(rule->signal, /*is_lhs=*/false); + f << ";\n"; + + bool first = true; + for (auto case_ : rule->cases) { + // The case attributes (for nested cases) are printed before the if/else if/else statement. + dump_attrs(rule); + f << indent; + if (!first) + f << "} else "; + first = false; + if (!case_->compare.empty()) { + f << "if ("; + bool first = true; + for (auto &compare : case_->compare) { + if (!first) + f << " || "; + first = false; + if (compare.is_fully_def()) { + f << signal_temp << " == "; + dump_sigspec(compare, /*is_lhs=*/false); + } else if (compare.is_fully_const()) { + RTLIL::Const compare_mask, compare_value; + for (auto bit : compare.as_const()) { + switch (bit) { + case RTLIL::S0: + case RTLIL::S1: + compare_mask.bits.push_back(RTLIL::S1); + compare_value.bits.push_back(bit); + break; + + case RTLIL::Sx: + case RTLIL::Sz: + case RTLIL::Sa: + compare_mask.bits.push_back(RTLIL::S0); + compare_value.bits.push_back(RTLIL::S0); + break; + + default: + log_assert(false); + } + } + f << "and_uu<" << compare.size() << ">(" << signal_temp << ", "; + dump_const(compare_mask); + f << ") == "; + dump_const(compare_value); + } else { + log_assert(false); + } + } + f << ") "; + } + f << "{\n"; + inc_indent(); + dump_case_rule(case_); + dec_indent(); + } + f << indent << "}\n"; + } + + void dump_process(const RTLIL::Process *proc) + { + dump_attrs(proc); + f << indent << "// process " << proc->name.str() << "\n"; + // The case attributes (for root case) are always empty. + log_assert(proc->root_case.attributes.empty()); + dump_case_rule(&proc->root_case); + for (auto sync : proc->syncs) { + RTLIL::SigBit sync_bit = sync->signal[0]; + sync_bit = sigmaps[sync_bit.wire->module](sync_bit); + + pool<std::string> events; + switch (sync->type) { + case RTLIL::STp: + events.insert("posedge_" + mangle(sync_bit)); + break; + case RTLIL::STn: + events.insert("negedge_" + mangle(sync_bit)); + case RTLIL::STe: + events.insert("posedge_" + mangle(sync_bit)); + events.insert("negedge_" + mangle(sync_bit)); + break; + + case RTLIL::ST0: + case RTLIL::ST1: + case RTLIL::STa: + case RTLIL::STg: + case RTLIL::STi: + log_assert(false); + } + if (!events.empty()) { + f << indent << "if ("; + bool first = true; + for (auto &event : events) { + if (!first) + f << " || "; + first = false; + f << event; + } + f << ") {\n"; + inc_indent(); + for (auto action : sync->actions) + dump_assign(action); + dec_indent(); + f << indent << "}\n"; + } + } + } + + void dump_wire(const RTLIL::Wire *wire, bool is_local) + { + if (elided_wires.count(wire)) + return; + + if (is_local) { + if (!localized_wires.count(wire)) + return; + + dump_attrs(wire); + f << indent << "value<" << wire->width << "> " << mangle(wire) << ";\n"; + } else { + if (localized_wires.count(wire)) + return; + + dump_attrs(wire); + f << indent << "wire<" << wire->width << "> " << mangle(wire); + if (wire->attributes.count(ID(init))) { + f << " "; + dump_const_init(wire->attributes.at(ID(init))); + } + f << ";\n"; + if (sync_wires[wire]) { + for (auto sync_type : sync_types) { + if (sync_type.first.wire == wire) { + if (sync_type.second != RTLIL::STn) + f << indent << "bool posedge_" << mangle(sync_type.first) << " = false;\n"; + if (sync_type.second != RTLIL::STp) + f << indent << "bool negedge_" << mangle(sync_type.first) << " = false;\n"; + } + } + } + } + } + + void dump_memory(RTLIL::Module *module, const RTLIL::Memory *memory) + { + vector<const RTLIL::Cell*> init_cells; + for (auto cell : module->cells()) + if (cell->type == ID($meminit) && cell->getParam(ID(MEMID)).decode_string() == memory->name.str()) + init_cells.push_back(cell); + + std::sort(init_cells.begin(), init_cells.end(), [](const RTLIL::Cell *a, const RTLIL::Cell *b) { + int a_addr = a->getPort(ID(ADDR)).as_int(), b_addr = b->getPort(ID(ADDR)).as_int(); + int a_prio = a->getParam(ID(PRIORITY)).as_int(), b_prio = b->getParam(ID(PRIORITY)).as_int(); + return a_prio > b_prio || (a_prio == b_prio && a_addr < b_addr); + }); + + dump_attrs(memory); + f << indent << (writable_memories[memory] ? "" : "const ") + << "memory<" << memory->width << "> " << mangle(memory) + << " { " << memory->size << "u"; + if (init_cells.empty()) { + f << " };\n"; + } else { + f << ",\n"; + inc_indent(); + for (auto cell : init_cells) { + dump_attrs(cell); + RTLIL::Const data = cell->getPort(ID(DATA)).as_const(); + size_t width = cell->getParam(ID(WIDTH)).as_int(); + size_t words = cell->getParam(ID(WORDS)).as_int(); + f << indent << "memory<" << memory->width << ">::init<" << words << "> { " + << stringf("%#x", cell->getPort(ID(ADDR)).as_int()) << ", {"; + inc_indent(); + for (size_t n = 0; n < words; n++) { + if (n % 4 == 0) + f << "\n" << indent; + else + f << " "; + dump_const(data, width, n * width, /*fixed_width=*/true); + f << ","; + } + dec_indent(); + f << "\n" << indent << "}},\n"; + } + dec_indent(); + f << indent << "};\n"; + } + } + + void dump_module(RTLIL::Module *module) + { + dump_attrs(module); + f << "struct " << mangle(module) << " : public module {\n"; + inc_indent(); + for (auto wire : module->wires()) + dump_wire(wire, /*is_local=*/false); + f << "\n"; + bool has_memories = false; + for (auto memory : module->memories) { + dump_memory(module, memory.second); + has_memories = true; + } + if (has_memories) + f << "\n"; + bool has_cells = false; + for (auto cell : module->cells()) { + if (is_internal_cell(cell->type)) + continue; + f << indent << mangle_module_name(cell->type) << " " << mangle(cell) << ";\n"; + has_cells = true; + } + if (has_cells) + f << "\n"; + f << indent << "void eval() override;\n"; + f << indent << "bool commit() override;\n"; + dec_indent(); + f << "}; // struct " << mangle(module) << "\n"; + f << "\n"; + + f << "void " << mangle(module) << "::eval() {\n"; + inc_indent(); + for (auto wire : module->wires()) + dump_wire(wire, /*is_local=*/true); + for (auto node : schedule[module]) { + switch (node.type) { + case FlowGraph::Node::Type::CONNECT: + dump_connect(node.connect); + break; + case FlowGraph::Node::Type::CELL: + dump_cell(node.cell); + break; + case FlowGraph::Node::Type::PROCESS: + dump_process(node.process); + break; + } + } + for (auto sync_type : sync_types) { + if (sync_type.first.wire->module == module) { + if (sync_type.second != RTLIL::STn) + f << indent << "posedge_" << mangle(sync_type.first) << " = false;\n"; + if (sync_type.second != RTLIL::STp) + f << indent << "negedge_" << mangle(sync_type.first) << " = false;\n"; + } + } + dec_indent(); + f << "}\n"; + f << "\n"; + + f << "bool " << mangle(module) << "::commit() {\n"; + inc_indent(); + f << indent << "bool changed = false;\n"; + for (auto wire : module->wires()) { + if (elided_wires.count(wire) || localized_wires.count(wire)) + continue; + if (sync_wires[wire]) { + std::string wire_prev = mangle(wire) + "_prev"; + std::string wire_curr = mangle(wire) + ".curr"; + std::string wire_edge = mangle(wire) + "_edge"; + f << indent << "value<" << wire->width << "> " << wire_prev << " = " << wire_curr << ";\n"; + f << indent << "if (" << mangle(wire) << ".commit()) {\n"; + inc_indent(); + f << indent << "value<" << wire->width << "> " << wire_edge << " = " + << wire_prev << ".bit_xor(" << wire_curr << ");\n"; + for (auto sync_type : sync_types) { + if (sync_type.first.wire != wire) + continue; + if (sync_type.second != RTLIL::STn) { + f << indent << "if (" << wire_edge << ".slice<" << sync_type.first.offset << ">().val() && " + << wire_curr << ".slice<" << sync_type.first.offset << ">().val())\n"; + inc_indent(); + f << indent << "posedge_" << mangle(sync_type.first) << " = true;\n"; + dec_indent(); + } + if (sync_type.second != RTLIL::STp) { + f << indent << "if (" << wire_edge << ".slice<" << sync_type.first.offset << ">().val() && " + << "!" << wire_curr << ".slice<" << sync_type.first.offset << ">().val())\n"; + inc_indent(); + f << indent << "negedge_" << mangle(sync_type.first) << " = true;\n"; + dec_indent(); + } + f << indent << "changed = true;\n"; + } + dec_indent(); + f << indent << "}\n"; + } else { + f << indent << "changed |= " << mangle(wire) << ".commit();\n"; + } + } + for (auto memory : module->memories) { + if (!writable_memories[memory.second]) + continue; + f << indent << "changed |= " << mangle(memory.second) << ".commit();\n"; + } + for (auto cell : module->cells()) { + if (is_internal_cell(cell->type)) + continue; + f << indent << "changed |= " << mangle(cell) << ".commit();\n"; + } + f << indent << "return changed;\n"; + dec_indent(); + f << "}\n"; + f << "\n"; + } + + void dump_design(RTLIL::Design *design) + { + TopoSort<RTLIL::Module*> topo_design; + for (auto module : design->modules()) { + if (module->get_blackbox_attribute() || !design->selected_module(module)) + continue; + topo_design.node(module); + + for (auto cell : module->cells()) { + if (is_internal_cell(cell->type)) + continue; + log_assert(design->has(cell->type)); + topo_design.edge(design->module(cell->type), module); + } + } + log_assert(topo_design.sort()); + + f << "#include <cxxrtl.h>\n"; + f << "\n"; + f << "using namespace cxxrtl_yosys;\n"; + f << "\n"; + f << "namespace cxxrtl_design {\n"; + f << "\n"; + for (auto module : topo_design.sorted) { + if (!design->selected_module(module)) + continue; + dump_module(module); + } + f << "} // namespace cxxrtl_design\n"; + } + + // Edge-type sync rules require us to emit edge detectors, which require coordination between + // eval and commit phases. To do this we need to collect them upfront. + // + // Note that the simulator commit phase operates at wire granularity but edge-type sync rules + // operate at wire bit granularity; it is possible to have code similar to: + // wire [3:0] clocks; + // always @(posedge clocks[0]) ... + // To handle this we track edge sensitivity both for wires and wire bits. + void register_edge_signal(SigMap &sigmap, RTLIL::SigSpec signal, RTLIL::SyncType type) + { + signal = sigmap(signal); + log_assert(signal.is_wire() && signal.is_bit()); + log_assert(type == RTLIL::STp || type == RTLIL::STn || type == RTLIL::STe); + + RTLIL::SigBit sigbit = signal[0]; + if (!sync_types.count(sigbit)) + sync_types[sigbit] = type; + else if (sync_types[sigbit] != type) + sync_types[sigbit] = RTLIL::STe; + sync_wires.insert(signal.as_wire()); + } + + void analyze_design(RTLIL::Design *design) + { + bool has_feedback_arcs = false; + for (auto module : design->modules()) { + if (!design->selected_module(module)) + continue; + + FlowGraph flow; + SigMap &sigmap = sigmaps[module]; + sigmap.set(module); + + for (auto conn : module->connections()) + flow.add_node(conn); + + dict<const RTLIL::Cell*, FlowGraph::Node*> memrw_cell_nodes; + dict<std::pair<RTLIL::SigBit, const RTLIL::Memory*>, + pool<const RTLIL::Cell*>> memwr_per_domain; + for (auto cell : module->cells()) { + FlowGraph::Node *node = flow.add_node(cell); + + // Various DFF cells are treated like posedge/negedge processes, see above for details. + if (cell->type.in(ID($dff), ID($dffe), ID($adff), ID($dffsr))) { + if (cell->getPort(ID(CLK)).is_wire()) + register_edge_signal(sigmap, cell->getPort(ID(CLK)), + cell->parameters[ID(CLK_POLARITY)].as_bool() ? RTLIL::STp : RTLIL::STn); + // The $adff and $dffsr cells are level-sensitive, not edge-sensitive (in spite of the fact that they + // are inferred from an edge-sensitive Verilog process) and do not correspond to an edge-type sync rule. + } + // Similar for memory port cells. + if (cell->type.in(ID($memrd), ID($memwr))) { + if (cell->getParam(ID(CLK_ENABLE)).as_bool()) { + if (cell->getPort(ID(CLK)).is_wire()) + register_edge_signal(sigmap, cell->getPort(ID(CLK)), + cell->parameters[ID(CLK_POLARITY)].as_bool() ? RTLIL::STp : RTLIL::STn); + } + memrw_cell_nodes[cell] = node; + } + // Optimize access to read-only memories. + if (cell->type == ID($memwr)) + writable_memories.insert(module->memories[cell->getParam(ID(MEMID)).decode_string()]); + // Collect groups of memory write ports in the same domain. + if (cell->type == ID($memwr) && cell->getParam(ID(CLK_ENABLE)).as_bool() && cell->getPort(ID(CLK)).is_wire()) { + RTLIL::SigBit clk_bit = sigmap(cell->getPort(ID(CLK)))[0]; + const RTLIL::Memory *memory = module->memories[cell->getParam(ID(MEMID)).decode_string()]; + memwr_per_domain[{clk_bit, memory}].insert(cell); + } + // Handling of packed memories is delegated to the `memory_unpack` pass, so we can rely on the presence + // of RTLIL memory objects and $memrd/$memwr/$meminit cells. + if (cell->type.in(ID($mem))) + log_assert(false); + } + for (auto cell : module->cells()) { + // Collect groups of memory write ports read by every transparent read port. + if (cell->type == ID($memrd) && cell->getParam(ID(CLK_ENABLE)).as_bool() && cell->getPort(ID(CLK)).is_wire() && + cell->getParam(ID(TRANSPARENT)).as_bool()) { + RTLIL::SigBit clk_bit = sigmap(cell->getPort(ID(CLK)))[0]; + const RTLIL::Memory *memory = module->memories[cell->getParam(ID(MEMID)).decode_string()]; + for (auto memwr_cell : memwr_per_domain[{clk_bit, memory}]) { + transparent_for[cell].insert(memwr_cell); + // Our implementation of transparent $memrd cells reads \EN, \ADDR and \DATA from every $memwr cell + // in the same domain, which isn't directly visible in the netlist. Add these uses explicitly. + flow.add_uses(memrw_cell_nodes[cell], memwr_cell->getPort(ID(EN))); + flow.add_uses(memrw_cell_nodes[cell], memwr_cell->getPort(ID(ADDR))); + flow.add_uses(memrw_cell_nodes[cell], memwr_cell->getPort(ID(DATA))); + } + } + } + + for (auto proc : module->processes) { + flow.add_node(proc.second); + + for (auto sync : proc.second->syncs) + switch (sync->type) { + // Edge-type sync rules require pre-registration. + case RTLIL::STp: + case RTLIL::STn: + case RTLIL::STe: + register_edge_signal(sigmap, sync->signal, sync->type); + break; + + // Level-type sync rules require no special handling. + case RTLIL::ST0: + case RTLIL::ST1: + case RTLIL::STa: + break; + + // Handling of init-type sync rules is delegated to the `proc_init` pass, so we can use the wire + // attribute regardless of input. + case RTLIL::STi: + log_assert(false); + + case RTLIL::STg: + log_cmd_error("Global clock is not supported.\n"); + } + } + + for (auto wire : module->wires()) { + if (!flow.is_elidable(wire)) continue; + if (wire->port_id != 0) continue; + if (wire->get_bool_attribute(ID(keep))) continue; + if (wire->name.begins_with("$") && !elide_internal) continue; + if (wire->name.begins_with("\\") && !elide_public) continue; + if (sync_wires[wire]) continue; + log_assert(flow.wire_defs[wire].size() == 1); + elided_wires[wire] = **flow.wire_defs[wire].begin(); + } + + // Elided wires that are outputs of internal cells are always connected to a well known port (Y). + // For user cells, there could be multiple of them, and we need a way to look up the port name + // knowing only the wire. + for (auto cell : module->cells()) + for (auto conn : cell->connections()) + if (conn.second.is_wire() && elided_wires.count(conn.second.as_wire())) + cell_wire_defs[cell][conn.second.as_wire()] = conn.first; + + dict<FlowGraph::Node*, pool<const RTLIL::Wire*>, hash_ptr_ops> node_defs; + for (auto wire_def : flow.wire_defs) + for (auto node : wire_def.second) + node_defs[node].insert(wire_def.first); + + Scheduler<FlowGraph::Node> scheduler; + dict<FlowGraph::Node*, Scheduler<FlowGraph::Node>::Vertex*, hash_ptr_ops> node_map; + for (auto node : flow.nodes) + node_map[node] = scheduler.add(node); + for (auto node_def : node_defs) { + auto vertex = node_map[node_def.first]; + for (auto wire : node_def.second) + for (auto succ_node : flow.wire_uses[wire]) { + auto succ_vertex = node_map[succ_node]; + vertex->succs.insert(succ_vertex); + succ_vertex->preds.insert(vertex); + } + } + + auto eval_order = scheduler.schedule(); + pool<FlowGraph::Node*, hash_ptr_ops> evaluated; + pool<const RTLIL::Wire*> feedback_wires; + for (auto vertex : eval_order) { + auto node = vertex->data; + schedule[module].push_back(*node); + // Any wire that is an output of node vo and input of node vi where vo is scheduled later than vi + // is a feedback wire. Feedback wires indicate apparent logic loops in the design, which may be + // caused by a true logic loop, but usually are a benign result of dependency tracking that works + // on wire, not bit, level. Nevertheless, feedback wires cannot be localized. + evaluated.insert(node); + for (auto wire : node_defs[node]) + for (auto succ_node : flow.wire_uses[wire]) + if (evaluated[succ_node]) { + feedback_wires.insert(wire); + // Feedback wires may never be elided because feedback requires state, but the point of elision + // (and localization) is to eliminate state. + elided_wires.erase(wire); + } + } + + if (!feedback_wires.empty()) { + has_feedback_arcs = true; + log("Module `%s` contains feedback arcs through wires:\n", module->name.c_str()); + for (auto wire : feedback_wires) { + log(" %s\n", wire->name.c_str()); + } + } + + for (auto wire : module->wires()) { + if (feedback_wires[wire]) continue; + if (wire->port_id != 0) continue; + if (wire->get_bool_attribute(ID(keep))) continue; + if (wire->name.begins_with("$") && !localize_internal) continue; + if (wire->name.begins_with("\\") && !localize_public) continue; + if (sync_wires[wire]) continue; + // Outputs of FF/$memrd cells and LHS of sync actions do not end up in defs. + if (flow.wire_defs[wire].size() != 1) continue; + localized_wires.insert(wire); + } + } + if (has_feedback_arcs) { + log("Feedback arcs require delta cycles during evaluation.\n"); + } + } + + void check_design(RTLIL::Design *design, bool &has_sync_init, bool &has_packed_mem) + { + has_sync_init = has_packed_mem = false; + + for (auto module : design->modules()) { + if (module->get_blackbox_attribute()) + continue; + + if (!design->selected_whole_module(module)) + if (design->selected_module(module)) + log_cmd_error("Can't handle partially selected module `%s`!\n", id2cstr(module->name)); + if (!design->selected_module(module)) + continue; + + for (auto proc : module->processes) + for (auto sync : proc.second->syncs) + if (sync->type == RTLIL::STi) + has_sync_init = true; + + for (auto cell : module->cells()) + if (cell->type == ID($mem)) + has_packed_mem = true; + } + } + + void prepare_design(RTLIL::Design *design) + { + bool has_sync_init, has_packed_mem; + check_design(design, has_sync_init, has_packed_mem); + if (has_sync_init) { + // We're only interested in proc_init, but it depends on proc_prune and proc_clean, so call those + // in case they weren't already. (This allows `yosys foo.v -o foo.cc` to work.) + Pass::call(design, "proc_prune"); + Pass::call(design, "proc_clean"); + Pass::call(design, "proc_init"); + } + if (has_packed_mem) + Pass::call(design, "memory_unpack"); + // Recheck the design if it was modified. + if (has_sync_init || has_packed_mem) + check_design(design, has_sync_init, has_packed_mem); + log_assert(!(has_sync_init || has_packed_mem)); + + if (run_splitnets) { + Pass::call(design, "splitnets -driver"); + Pass::call(design, "opt_clean -purge"); + } + log("\n"); + analyze_design(design); + } +}; + +struct CxxrtlBackend : public Backend { + static const int DEFAULT_OPT_LEVEL = 5; + + CxxrtlBackend() : Backend("cxxrtl", "convert design to C++ RTL simulation") { } + void help() YS_OVERRIDE + { + // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---| + log("\n"); + log(" write_cxxrtl [options] [filename]\n"); + log("\n"); + log("Write C++ code for simulating the design. The generated code requires a driver;\n"); + log("the following simple driver is provided as an example:\n"); + log("\n"); + log(" #include \"top.cc\"\n"); + log("\n"); + log(" int main() {\n"); + log(" cxxrtl_design::p_top top;\n"); + log(" while (1) {\n"); + log(" top.p_clk.next = value<1> {1u};\n"); + log(" top.step();\n"); + log(" top.p_clk.next = value<1> {0u};\n"); + log(" top.step();\n"); + log(" }\n"); + log(" }\n"); + log("\n"); + log("The following options are supported by this backend:\n"); + log("\n"); + log(" -O <level>\n"); + log(" set the optimization level. the default is -O%d. higher optimization\n", DEFAULT_OPT_LEVEL); + log(" levels dramatically decrease compile and run time, and highest level\n"); + log(" possible for a design should be used.\n"); + log("\n"); + log(" -O0\n"); + log(" no optimization.\n"); + log("\n"); + log(" -O1\n"); + log(" elide internal wires if possible.\n"); + log("\n"); + log(" -O2\n"); + log(" like -O1, and localize internal wires if possible.\n"); + log("\n"); + log(" -O3\n"); + log(" like -O2, and elide public wires not marked (*keep*) if possible.\n"); + log("\n"); + log(" -O4\n"); + log(" like -O3, and localize public wires not marked (*keep*) if possible.\n"); + log("\n"); + log(" -O5\n"); + log(" like -O4, and run `splitnets -driver; opt_clean -purge` first.\n"); + log("\n"); + } + void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE + { + int opt_level = DEFAULT_OPT_LEVEL; + + log_header(design, "Executing CXXRTL backend.\n"); + + size_t argidx; + for (argidx = 1; argidx < args.size(); argidx++) + { + if (args[argidx] == "-O" && argidx+1 < args.size()) { + opt_level = std::stoi(args[++argidx]); + continue; + } + if (args[argidx].substr(0, 2) == "-O" && args[argidx].size() == 3 && isdigit(args[argidx][2])) { + opt_level = std::stoi(args[argidx].substr(2)); + continue; + } + break; + } + extra_args(f, filename, args, argidx); + + CxxrtlWorker worker(*f); + switch (opt_level) { + case 5: + worker.run_splitnets = true; + case 4: + worker.localize_public = true; + case 3: + worker.elide_public = true; + case 2: + worker.localize_internal = true; + case 1: + worker.elide_internal = true; + case 0: + break; + default: + log_cmd_error("Invalid optimization level %d.\n", opt_level); + } + worker.prepare_design(design); + worker.dump_design(design); + } +} CxxrtlBackend; + +PRIVATE_NAMESPACE_END |