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yosys/backends/cxxrtl/cxxrtl.cc

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/*
* 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;
}
};
bool is_input_wire(const RTLIL::Wire *wire)
{
return wire->port_input && !wire->port_output;
}
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($neg));
}
bool is_binary_cell(RTLIL::IdString type)
{
return type.in(
ID($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));
}
bool is_elidable_cell(RTLIL::IdString type)
{
return is_unary_cell(type) || is_binary_cell(type) || type.in(
ID($mux), ID($concat), ID($slice));
}
bool is_sync_ff_cell(RTLIL::IdString type)
{
return type.in(
ID($dff), ID($dffe));
}
bool is_ff_cell(RTLIL::IdString type)
{
return is_sync_ff_cell(type) || type.in(
ID($adff), ID($dffsr), ID($dlatch), ID($dlatchsr), ID($sr));
}
bool is_internal_cell(RTLIL::IdString type)
{
return type[0] == '$' && !type.begins_with("$paramod");
}
bool is_cxxrtl_blackbox_cell(const RTLIL::Cell *cell)
{
RTLIL::Module *cell_module = cell->module->design->module(cell->type);
log_assert(cell_module != nullptr);
return cell_module->get_bool_attribute(ID(cxxrtl_blackbox));
}
enum class CxxrtlPortType {
UNKNOWN = 0, // or mixed comb/sync
COMB = 1,
SYNC = 2,
};
CxxrtlPortType cxxrtl_port_type(const RTLIL::Cell *cell, RTLIL::IdString port)
{
RTLIL::Module *cell_module = cell->module->design->module(cell->type);
if (cell_module == nullptr || !cell_module->get_bool_attribute(ID(cxxrtl_blackbox)))
return CxxrtlPortType::UNKNOWN;
RTLIL::Wire *cell_output_wire = cell_module->wire(port);
log_assert(cell_output_wire != nullptr);
bool is_comb = cell_output_wire->get_bool_attribute(ID(cxxrtl_comb));
bool is_sync = cell_output_wire->get_bool_attribute(ID(cxxrtl_sync));
if (is_comb && is_sync)
log_cmd_error("Port `%s.%s' is marked as both `cxxrtl_comb` and `cxxrtl_sync`.\n",
log_id(cell_module), log_signal(cell_output_wire));
else if (is_comb)
return CxxrtlPortType::COMB;
else if (is_sync)
return CxxrtlPortType::SYNC;
return CxxrtlPortType::UNKNOWN;
}
bool is_cxxrtl_comb_port(const RTLIL::Cell *cell, RTLIL::IdString port)
{
return cxxrtl_port_type(cell, port) == CxxrtlPortType::COMB;
}
bool is_cxxrtl_sync_port(const RTLIL::Cell *cell, RTLIL::IdString port)
{
return cxxrtl_port_type(cell, port) == CxxrtlPortType::SYNC;
}
struct FlowGraph {
struct Node {
enum class Type {
CONNECT,
CELL_SYNC,
CELL_EVAL,
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_comb_defs, wire_sync_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 fully_sync, bool elidable)
{
for (auto chunk : sig.chunks())
if (chunk.wire) {
if (fully_sync)
wire_sync_defs[chunk.wire].insert(node);
else
wire_comb_defs[chunk.wire].insert(node);
}
// Only comb defs of an entire wire in the right order can be elided.
if (!fully_sync && 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, /*fully_sync=*/false, /*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_sync_defs(Node *node, const RTLIL::Cell *cell)
{
// To understand why this node type is necessary and why it produces comb defs, consider a cell
// with input \i and sync output \o, used in a design such that \i is connected to \o. This does
// not result in a feedback arc because the output is synchronous. However, a naive implementation
// of code generation for cells that assigns to inputs, evaluates cells, assigns from outputs
// would not be able to immediately converge...
//
// wire<1> i_tmp;
// cell->p_i = i_tmp.curr;
// cell->eval();
// i_tmp.next = cell->p_o.curr;
//
// ... since the wire connecting the input and output ports would not be localizable. To solve
// this, the cell is split into two scheduling nodes; one exclusively for sync outputs, and
// another for inputs and all non-sync outputs. This way the generated code can be rearranged...
//
// value<1> i_tmp;
// i_tmp = cell->p_o.curr;
// cell->p_i = i_tmp;
// cell->eval();
//
// eliminating the unnecessary delta cycle. Conceptually, the CELL_SYNC node type is a series of
// connections of the form `connect \lhs \cell.\sync_output`; the right-hand side of these is not
// as a wire in RTLIL. If it was expressible, then `\cell.\sync_output` would have a sync def,
// and this node would be an ordinary CONNECT node, with `\lhs` having a comb def. Because it isn't,
// a special node type is used, the right-hand side does not appear anywhere, and the left-hand
// side has a comb def.
for (auto conn : cell->connections())
if (cell->output(conn.first))
if (is_cxxrtl_sync_port(cell, conn.first)) {
// See note regarding elidability below.
add_defs(node, conn.second, /*fully_sync=*/false, /*elidable=*/false);
}
}
void add_cell_eval_defs_uses(Node *node, const RTLIL::Cell *cell)
{
for (auto conn : cell->connections()) {
if (cell->output(conn.first)) {
if (is_elidable_cell(cell->type))
add_defs(node, conn.second, /*fully_sync=*/false, /*elidable=*/true);
else if (is_sync_ff_cell(cell->type) || (cell->type == ID($memrd) && cell->getParam(ID::CLK_ENABLE).as_bool()))
add_defs(node, conn.second, /*fully_sync=*/true, /*elidable=*/false);
else if (is_internal_cell(cell->type))
add_defs(node, conn.second, /*fully_sync=*/false, /*elidable=*/false);
else if (!is_cxxrtl_sync_port(cell, conn.first)) {
// Although at first it looks like outputs of user-defined cells may always be elided, the reality is
// more complex. Fully sync outputs produce no defs and so don't participate in elision. Fully comb
// outputs are assigned in a different way depending on whether the cell's eval() immediately converged.
// Unknown/mixed outputs could be elided, but should be rare in practical designs and don't justify
// the infrastructure required to elide outputs of cells with many of them.
add_defs(node, conn.second, /*fully_sync=*/false, /*elidable=*/false);
}
}
if (cell->input(conn.first))
add_uses(node, conn.second);
}
}
Node *add_node(const RTLIL::Cell *cell)
{
log_assert(cell->known());
bool has_fully_sync_outputs = false;
for (auto conn : cell->connections())
if (cell->output(conn.first) && is_cxxrtl_sync_port(cell, conn.first)) {
has_fully_sync_outputs = true;
break;
}
if (has_fully_sync_outputs) {
Node *node = new Node;
node->type = Node::Type::CELL_SYNC;
node->cell = cell;
nodes.push_back(node);
add_cell_sync_defs(node, cell);
}
Node *node = new Node;
node->type = Node::Type::CELL_EVAL;
node->cell = cell;
nodes.push_back(node);
add_cell_eval_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, /*is_sync=*/false, /*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)
add_defs(node, action.first, /*is_sync=*/true, /*elidable=*/false);
else
add_defs(node, action.first, /*is_sync=*/false, /*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;
}
};
std::vector<std::string> split_by(const std::string &str, const std::string &sep)
{
std::vector<std::string> result;
size_t prev = 0;
while (true) {
size_t curr = str.find_first_of(sep, prev + 1);
if (curr > str.size())
curr = str.size();
if (curr > prev + 1)
result.push_back(str.substr(prev, curr - prev));
if (curr == str.size())
break;
prev = curr;
}
return result;
}
std::string escape_cxx_string(const std::string &input)
{
std::string output = "\"";
for (auto c : input) {
if (::isprint(c)) {
if (c == '\\')
output.push_back('\\');
output.push_back(c);
} else {
char l = c & 0xf, h = (c >> 4) & 0xf;
output.append("\\x");
output.push_back((h < 10 ? '0' + h : 'a' + h - 10));
output.push_back((l < 10 ? '0' + l : 'a' + l - 10));
}
}
output.push_back('"');
if (output.find('\0') != std::string::npos) {
output.insert(0, "std::string {");
output.append(stringf(", %zu}", input.size()));
}
return output;
}
struct CxxrtlWorker {
bool split_intf = false;
std::string intf_filename;
std::string design_ns = "cxxrtl_design";
std::ostream *impl_f = nullptr;
std::ostream *intf_f = nullptr;
bool elide_internal = false;
bool elide_public = false;
bool localize_internal = false;
bool localize_public = false;
bool run_opt_clean_purge = false;
bool run_proc_flatten = false;
bool max_opt_level = false;
std::ostringstream f;
std::string indent;
int temporary = 0;
dict<const RTLIL::Module*, SigMap> sigmaps;
pool<const RTLIL::Wire*> edge_wires;
dict<RTLIL::SigBit, RTLIL::SyncType> edge_types;
pool<const RTLIL::Memory*> writable_memories;
dict<const RTLIL::Cell*, pool<const RTLIL::Cell*>> transparent_for;
dict<const RTLIL::Wire*, FlowGraph::Node> elided_wires;
dict<const RTLIL::Module*, std::vector<FlowGraph::Node>> schedule;
pool<const RTLIL::Wire*> localized_wires;
dict<const RTLIL::Module*, pool<std::string>> blackbox_specializations;
dict<const RTLIL::Module*, bool> eval_converges;
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, bool is_blackbox = false)
{
// Class namespace.
if (is_blackbox)
return "bb_" + mangle_name(name);
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, /*is_blackbox=*/module->get_bool_attribute(ID(cxxrtl_blackbox)));
}
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::vector<std::string> template_param_names(const RTLIL::Module *module)
{
if (!module->has_attribute(ID(cxxrtl_template)))
return {};
if (module->attributes.at(ID(cxxrtl_template)).flags != RTLIL::CONST_FLAG_STRING)
log_cmd_error("Attribute `cxxrtl_template' of module `%s' is not a string.\n", log_id(module));
std::vector<std::string> param_names = split_by(module->get_string_attribute(ID(cxxrtl_template)), " \t");
for (const auto &param_name : param_names) {
// Various lowercase prefixes (p_, i_, cell_, ...) are used for member variables, so require
// parameters to start with an uppercase letter to avoid name conflicts. (This is the convention
// in both Verilog and C++, anyway.)
if (!isupper(param_name[0]))
log_cmd_error("Attribute `cxxrtl_template' of module `%s' includes a parameter `%s', "
"which does not start with an uppercase letter.\n",
log_id(module), param_name.c_str());
}
return param_names;
}
std::string template_params(const RTLIL::Module *module, bool is_decl)
{
std::vector<std::string> param_names = template_param_names(module);
if (param_names.empty())
return "";
std::string params = "<";
bool first = true;
for (const auto &param_name : param_names) {
if (!first)
params += ", ";
first = false;
if (is_decl)
params += "size_t ";
params += param_name;
}
params += ">";
return params;
}
std::string template_args(const RTLIL::Cell *cell)
{
RTLIL::Module *cell_module = cell->module->design->module(cell->type);
log_assert(cell_module != nullptr);
if (!cell_module->get_bool_attribute(ID(cxxrtl_blackbox)))
return "";
std::vector<std::string> param_names = template_param_names(cell_module);
if (param_names.empty())
return "";
std::string params = "<";
bool first = true;
for (const auto &param_name : param_names) {
if (!first)
params += ", ";
first = false;
params += "/*" + param_name + "=*/";
RTLIL::IdString id_param_name = '\\' + param_name;
if (!cell->hasParam(id_param_name))
log_cmd_error("Cell `%s.%s' does not have a parameter `%s', which is required by the templated module `%s'.\n",
log_id(cell->module), log_id(cell), param_name.c_str(), log_id(cell_module));
RTLIL::Const param_value = cell->getParam(id_param_name);
if (((param_value.flags & ~RTLIL::CONST_FLAG_SIGNED) != 0) || param_value.as_int() < 0)
log_cmd_error("Parameter `%s' of cell `%s.%s', which is required by the templated module `%s', "
"is not a positive integer.\n",
param_name.c_str(), log_id(cell->module), log_id(cell), log_id(cell_module));
params += std::to_string(cell->getParam(id_param_name).as_int());
}
params += ">";
return params;
}
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)
{
const int CHUNK_SIZE = 32;
f << "{";
while (width > 0) {
int chunk_width = min(width, CHUNK_SIZE);
uint32_t chunk = data.extract(offset, chunk_width).as_int();
if (fixed_width)
f << stringf("0x%.*xu", (3 + chunk_width) / 4, 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_EVAL:
log_assert(is_elidable_cell(node.cell->type));
dump_cell_elided(node.cell);
break;
default:
log_assert(false);
}
} else if (localized_wires[chunk.wire] || is_input_wire(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_EVAL:
collect_cell_eval(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_sync(const RTLIL::Cell *cell)
{
const char *access = is_cxxrtl_blackbox_cell(cell) ? "->" : ".";
f << indent << "// cell " << cell->name.str() << " syncs\n";
for (auto conn : cell->connections())
if (cell->output(conn.first))
if (is_cxxrtl_sync_port(cell, conn.first)) {
f << indent;
dump_sigspec_lhs(conn.second);
f << " = " << mangle(cell) << access << mangle_wire_name(conn.first) << ".curr;\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_eval(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_eval(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)) {
bool has_enable = cell->getParam(ID::CLK_ENABLE).as_bool() && !cell->getPort(ID::EN).is_fully_ones();
if (has_enable) {
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 (has_enable) {
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());
const char *access = is_cxxrtl_blackbox_cell(cell) ? "->" : ".";
for (auto conn : cell->connections())
if (cell->input(conn.first) && !cell->output(conn.first)) {
f << indent << mangle(cell) << access << mangle_wire_name(conn.first) << " = ";
dump_sigspec_rhs(conn.second);
f << ";\n";
if (getenv("CXXRTL_VOID_MY_WARRANTY")) {
// Until we have proper clock tree detection, this really awful hack that opportunistically
// propagates prev_* values for clocks can be used to estimate how much faster a design could
// be if only one clock edge was simulated by replacing:
// top.p_clk = value<1>{0u}; top.step();
// top.p_clk = value<1>{1u}; top.step();
// with:
// top.prev_p_clk = value<1>{0u}; top.p_clk = value<1>{1u}; top.step();
// Don't rely on this; it will be removed without warning.
RTLIL::Module *cell_module = cell->module->design->module(cell->type);
if (cell_module != nullptr && cell_module->wire(conn.first) && conn.second.is_wire()) {
RTLIL::Wire *cell_module_wire = cell_module->wire(conn.first);
if (edge_wires[conn.second.as_wire()] && edge_wires[cell_module_wire]) {
f << indent << mangle(cell) << access << "prev_" << mangle(cell_module_wire) << " = ";
f << "prev_" << mangle(conn.second.as_wire()) << ";\n";
}
}
}
} else if (cell->input(conn.first)) {
f << indent << mangle(cell) << access << mangle_wire_name(conn.first) << ".next = ";
dump_sigspec_rhs(conn.second);
f << ";\n";
}
auto assign_from_outputs = [&](bool cell_converged) {
for (auto conn : cell->connections()) {
if (cell->output(conn.first)) {
if (conn.second.empty())
continue; // ignore disconnected ports
if (is_cxxrtl_sync_port(cell, conn.first))
continue; // fully sync ports are handled in CELL_SYNC nodes
f << indent;
dump_sigspec_lhs(conn.second);
f << " = " << mangle(cell) << access << mangle_wire_name(conn.first);
// Similarly to how there is no purpose to buffering cell inputs, there is also no purpose to buffering
// combinatorial cell outputs in case the cell converges within one cycle. (To convince yourself that
// this optimization is valid, consider that, since the cell converged within one cycle, it would not
// have any buffered wires if they were not output ports. Imagine inlining the cell's eval() function,
// and consider the fate of the localized wires that used to be output ports.)
//
// Unlike cell inputs (which are never buffered), it is not possible to know apriori whether the cell
// (which may be late bound) will converge immediately. Because of this, the choice between using .curr
// (appropriate for buffered outputs) and .next (appropriate for unbuffered outputs) is made at runtime.
if (cell_converged && is_cxxrtl_comb_port(cell, conn.first))
f << ".next;\n";
else
f << ".curr;\n";
}
}
};
f << indent << "if (" << mangle(cell) << access << "eval()) {\n";
inc_indent();
assign_from_outputs(/*cell_converged=*/true);
dec_indent();
f << indent << "} else {\n";
inc_indent();
f << indent << "converged = false;\n";
assign_from_outputs(/*cell_converged=*/false);
dec_indent();
f << indent << "}\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;
if (!sync->signal.empty()) {
sync_bit = sync->signal[0];
sync_bit = sigmaps[sync_bit.wire->module](sync_bit);
}
pool<std::string> events;
switch (sync->type) {
case RTLIL::STp:
log_assert(sync_bit.wire != nullptr);
events.insert("posedge_" + mangle(sync_bit));
break;
case RTLIL::STn:
log_assert(sync_bit.wire != nullptr);
events.insert("negedge_" + mangle(sync_bit));
break;
case RTLIL::STe:
log_assert(sync_bit.wire != nullptr);
events.insert("posedge_" + mangle(sync_bit));
events.insert("negedge_" + mangle(sync_bit));
break;
case RTLIL::STa:
events.insert("true");
break;
case RTLIL::ST0:
case RTLIL::ST1:
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_context)
{
if (elided_wires.count(wire))
return;
if (localized_wires.count(wire) != is_local_context)
return;
if (is_local_context) {
dump_attrs(wire);
f << indent << "value<" << wire->width << "> " << mangle(wire) << ";\n";
} else {
std::string width;
if (wire->module->has_attribute(ID(cxxrtl_blackbox)) && wire->has_attribute(ID(cxxrtl_width))) {
width = wire->get_string_attribute(ID(cxxrtl_width));
} else {
width = std::to_string(wire->width);
}
dump_attrs(wire);
f << indent << (is_input_wire(wire) ? "value" : "wire") << "<" << width << "> " << mangle(wire);
if (wire->has_attribute(ID::init)) {
f << " ";
dump_const_init(wire->attributes.at(ID::init));
}
f << ";\n";
if (edge_wires[wire]) {
if (is_input_wire(wire)) {
f << indent << "value<" << width << "> prev_" << mangle(wire);
if (wire->has_attribute(ID::init)) {
f << " ";
dump_const_init(wire->attributes.at(ID::init));
}
f << ";\n";
}
for (auto edge_type : edge_types) {
if (edge_type.first.wire == wire) {
std::string prev, next;
if (is_input_wire(wire)) {
prev = "prev_" + mangle(edge_type.first.wire);
next = mangle(edge_type.first.wire);
} else {
prev = mangle(edge_type.first.wire) + ".curr";
next = mangle(edge_type.first.wire) + ".next";
}
prev += ".slice<" + std::to_string(edge_type.first.offset) + ">().val()";
next += ".slice<" + std::to_string(edge_type.first.offset) + ">().val()";
if (edge_type.second != RTLIL::STn) {
f << indent << "bool posedge_" << mangle(edge_type.first) << "() const {\n";
inc_indent();
f << indent << "return !" << prev << " && " << next << ";\n";
dec_indent();
f << indent << "}\n";
}
if (edge_type.second != RTLIL::STp) {
f << indent << "bool negedge_" << mangle(edge_type.first) << "() const {\n";
inc_indent();
f << indent << "return " << prev << " && !" << next << ";\n";
dec_indent();
f << indent << "}\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 << "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_eval_method(RTLIL::Module *module)
{
inc_indent();
f << indent << "bool converged = " << (eval_converges.at(module) ? "true" : "false") << ";\n";
if (!module->get_bool_attribute(ID(cxxrtl_blackbox))) {
for (auto wire : module->wires()) {
if (edge_wires[wire]) {
for (auto edge_type : edge_types) {
if (edge_type.first.wire == wire) {
if (edge_type.second != RTLIL::STn) {
f << indent << "bool posedge_" << mangle(edge_type.first) << " = ";
f << "this->posedge_" << mangle(edge_type.first) << "();\n";
}
if (edge_type.second != RTLIL::STp) {
f << indent << "bool negedge_" << mangle(edge_type.first) << " = ";
f << "this->negedge_" << mangle(edge_type.first) << "();\n";
}
}
}
}
}
for (auto wire : module->wires())
dump_wire(wire, /*is_local_context=*/true);
for (auto node : schedule[module]) {
switch (node.type) {
case FlowGraph::Node::Type::CONNECT:
dump_connect(node.connect);
break;
case FlowGraph::Node::Type::CELL_SYNC:
dump_cell_sync(node.cell);
break;
case FlowGraph::Node::Type::CELL_EVAL:
dump_cell_eval(node.cell);
break;
case FlowGraph::Node::Type::PROCESS:
dump_process(node.process);
break;
}
}
}
f << indent << "return converged;\n";
dec_indent();
}
void dump_commit_method(RTLIL::Module *module)
{
inc_indent();
f << indent << "bool changed = false;\n";
for (auto wire : module->wires()) {
if (elided_wires.count(wire) || localized_wires.count(wire))
continue;
if (is_input_wire(wire)) {
if (edge_wires[wire])
f << indent << "prev_" << mangle(wire) << " = " << mangle(wire) << ";\n";
continue;
}
if (!module->get_bool_attribute(ID(cxxrtl_blackbox)) || wire->port_id != 0)
f << indent << "changed |= " << mangle(wire) << ".commit();\n";
}
if (!module->get_bool_attribute(ID(cxxrtl_blackbox))) {
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;
const char *access = is_cxxrtl_blackbox_cell(cell) ? "->" : ".";
f << indent << "changed |= " << mangle(cell) << access << "commit();\n";
}
}
f << indent << "return changed;\n";
dec_indent();
}
void dump_metadata_map(const dict<RTLIL::IdString, RTLIL::Const> &metadata_map)
{
if (metadata_map.empty()) {
f << "metadata_map()";
return;
}
f << "metadata_map({\n";
inc_indent();
for (auto metadata_item : metadata_map) {
if (!metadata_item.first.begins_with("\\"))
continue;
f << indent << "{ " << escape_cxx_string(metadata_item.first.str().substr(1)) << ", ";
if (metadata_item.second.flags & RTLIL::CONST_FLAG_REAL) {
f << std::showpoint << std::stod(metadata_item.second.decode_string()) << std::noshowpoint;
} else if (metadata_item.second.flags & RTLIL::CONST_FLAG_STRING) {
f << escape_cxx_string(metadata_item.second.decode_string());
} else {
f << metadata_item.second.as_int(/*is_signed=*/metadata_item.second.flags & RTLIL::CONST_FLAG_SIGNED);
if (!(metadata_item.second.flags & RTLIL::CONST_FLAG_SIGNED))
f << "u";
}
f << " },\n";
}
dec_indent();
f << indent << "})";
}
void dump_module_intf(RTLIL::Module *module)
{
dump_attrs(module);
if (module->get_bool_attribute(ID(cxxrtl_blackbox))) {
if (module->has_attribute(ID(cxxrtl_template)))
f << indent << "template" << template_params(module, /*is_decl=*/true) << "\n";
f << indent << "struct " << mangle(module) << " : public module {\n";
inc_indent();
for (auto wire : module->wires()) {
if (wire->port_id != 0)
dump_wire(wire, /*is_local_context=*/false);
}
f << "\n";
f << indent << "bool eval() override {\n";
dump_eval_method(module);
f << indent << "}\n";
f << "\n";
f << indent << "bool commit() override {\n";
dump_commit_method(module);
f << indent << "}\n";
f << "\n";
f << indent << "static std::unique_ptr<" << mangle(module);
f << template_params(module, /*is_decl=*/false) << "> ";
f << "create(std::string name, metadata_map parameters, metadata_map attributes);\n";
dec_indent();
f << indent << "}; // struct " << mangle(module) << "\n";
f << "\n";
if (blackbox_specializations.count(module)) {
// If templated black boxes are used, the constructor of any module which includes the black box cell
// (which calls the declared but not defined in the generated code `create` function) may only be used
// if (a) the create function is defined in the same translation unit, or (b) the create function has
// a forward-declared explicit specialization.
//
// Option (b) makes it possible to have the generated code and the black box implementation in different
// translation units, which is convenient. Of course, its downside is that black boxes must predefine
// a specialization for every combination of parameters the generated code may use; but since the main
// purpose of templated black boxes is abstracting over datapath width, it is expected that there would
// be very few such combinations anyway.
for (auto specialization : blackbox_specializations[module]) {
f << indent << "template<>\n";
f << indent << "std::unique_ptr<" << mangle(module) << specialization << "> ";
f << mangle(module) << specialization << "::";
f << "create(std::string name, metadata_map parameters, metadata_map attributes);\n";
f << "\n";
}
}
} else {
f << indent << "struct " << mangle(module) << " : public module {\n";
inc_indent();
for (auto wire : module->wires())
dump_wire(wire, /*is_local_context=*/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;
dump_attrs(cell);
RTLIL::Module *cell_module = module->design->module(cell->type);
log_assert(cell_module != nullptr);
if (cell_module->get_bool_attribute(ID(cxxrtl_blackbox))) {
f << indent << "std::unique_ptr<" << mangle(cell_module) << template_args(cell) << "> ";
f << mangle(cell) << " = " << mangle(cell_module) << template_args(cell);
f << "::create(" << escape_cxx_string(cell->name.str()) << ", ";
dump_metadata_map(cell->parameters);
f << ", ";
dump_metadata_map(cell->attributes);
f << ");\n";
} else {
f << indent << mangle(cell_module) << " " << mangle(cell) << ";\n";
}
has_cells = true;
}
if (has_cells)
f << "\n";
f << indent << "bool eval() override;\n";
f << indent << "bool commit() override;\n";
dec_indent();
f << indent << "}; // struct " << mangle(module) << "\n";
f << "\n";
}
}
void dump_module_impl(RTLIL::Module *module)
{
if (module->get_bool_attribute(ID(cxxrtl_blackbox)))
return;
f << indent << "bool " << mangle(module) << "::eval() {\n";
dump_eval_method(module);
f << indent << "}\n";
f << "\n";
f << indent << "bool " << mangle(module) << "::commit() {\n";
dump_commit_method(module);
f << indent << "}\n";
f << "\n";
}
void dump_design(RTLIL::Design *design)
{
std::vector<RTLIL::Module*> modules;
TopoSort<RTLIL::Module*> topo_design;
for (auto module : design->modules()) {
if (!design->selected_module(module))
continue;
if (module->get_bool_attribute(ID(cxxrtl_blackbox)))
modules.push_back(module); // cxxrtl blackboxes first
if (module->get_blackbox_attribute() || module->get_bool_attribute(ID(cxxrtl_blackbox)))
continue;
topo_design.node(module);
for (auto cell : module->cells()) {
if (is_internal_cell(cell->type) || is_cxxrtl_blackbox_cell(cell))
continue;
RTLIL::Module *cell_module = design->module(cell->type);
log_assert(cell_module != nullptr);
topo_design.edge(cell_module, module);
}
}
log_assert(topo_design.sort());
modules.insert(modules.end(), topo_design.sorted.begin(), topo_design.sorted.end());
if (split_intf) {
// The only thing more depraved than include guards, is mangling filenames to turn them into include guards.
std::string include_guard = design_ns + "_header";
std::transform(include_guard.begin(), include_guard.end(), include_guard.begin(), ::toupper);
f << "#ifndef " << include_guard << "\n";
f << "#define " << include_guard << "\n";
f << "\n";
f << "#include <backends/cxxrtl/cxxrtl.h>\n";
f << "\n";
f << "using namespace cxxrtl;\n";
f << "\n";
f << "namespace " << design_ns << " {\n";
f << "\n";
for (auto module : modules)
dump_module_intf(module);
f << "} // namespace " << design_ns << "\n";
f << "\n";
f << "#endif\n";
*intf_f << f.str(); f.str("");
}
if (split_intf)
f << "#include \"" << intf_filename << "\"\n";
else
f << "#include <backends/cxxrtl/cxxrtl.h>\n";
f << "\n";
f << "using namespace cxxrtl_yosys;\n";
f << "\n";
f << "namespace " << design_ns << " {\n";
f << "\n";
for (auto module : modules) {
if (!split_intf)
dump_module_intf(module);
dump_module_impl(module);
}
f << "} // namespace " << design_ns << "\n";
*impl_f << f.str(); f.str("");
}
// 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 (!edge_types.count(sigbit))
edge_types[sigbit] = type;
else if (edge_types[sigbit] != type)
edge_types[sigbit] = RTLIL::STe;
edge_wires.insert(signal.as_wire());
}
void analyze_design(RTLIL::Design *design)
{
bool has_feedback_arcs = false;
bool has_buffered_wires = false;
for (auto module : design->modules()) {
if (!design->selected_module(module))
continue;
SigMap &sigmap = sigmaps[module];
sigmap.set(module);
if (module->get_bool_attribute(ID(cxxrtl_blackbox))) {
for (auto port : module->ports) {
RTLIL::Wire *wire = module->wire(port);
if (wire->has_attribute(ID(cxxrtl_edge))) {
RTLIL::Const edge_attr = wire->attributes[ID(cxxrtl_edge)];
if (!(edge_attr.flags & RTLIL::CONST_FLAG_STRING) || (int)edge_attr.decode_string().size() != GetSize(wire))
log_cmd_error("Attribute `cxxrtl_edge' of port `%s.%s' is not a string with one character per bit.\n",
log_id(module), log_signal(wire));
std::string edges = wire->get_string_attribute(ID(cxxrtl_edge));
for (int i = 0; i < GetSize(wire); i++) {
RTLIL::SigSpec wire_sig = wire;
switch (edges[i]) {
case '-': break;
case 'p': register_edge_signal(sigmap, wire_sig[i], RTLIL::STp); break;
case 'n': register_edge_signal(sigmap, wire_sig[i], RTLIL::STn); break;
case 'a': register_edge_signal(sigmap, wire_sig[i], RTLIL::STe); break;
default:
log_cmd_error("Attribute `cxxrtl_edge' of port `%s.%s' contains specifiers "
"other than '-', 'p', 'n', or 'a'.\n",
log_id(module), log_signal(wire));
}
}
}
}
// Black boxes converge by default, since their implementations are quite unlikely to require
// internal propagation of comb signals.
eval_converges[module] = true;
continue;
}
FlowGraph flow;
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()) {
if (!cell->known())
log_cmd_error("Unknown cell `%s'.\n", log_id(cell->type));
RTLIL::Module *cell_module = design->module(cell->type);
if (cell_module &&
cell_module->get_blackbox_attribute() &&
!cell_module->get_bool_attribute(ID(cxxrtl_blackbox)))
log_cmd_error("External blackbox cell `%s' is not marked as a CXXRTL blackbox.\n", log_id(cell->type));
if (cell_module &&
cell_module->get_bool_attribute(ID(cxxrtl_blackbox)) &&
cell_module->get_bool_attribute(ID(cxxrtl_template)))
blackbox_specializations[cell_module].insert(template_args(cell));
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($dffsr))) {
if (cell->getPort(ID::CLK).is_wire())
register_edge_signal(sigmap, cell->getPort(ID::CLK),
cell->parameters[ID::CLK_POLARITY].as_bool() ? RTLIL::STp : RTLIL::STn);
}
// Similar for memory port cells.
if (cell->type.in(ID($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 $memwr cell
// in the same domain, which isn't directly visible in the netlist. Add these uses explicitly.
flow.add_uses(memrw_cell_nodes[cell], memwr_cell->getPort(ID::EN));
flow.add_uses(memrw_cell_nodes[cell], memwr_cell->getPort(ID::ADDR));
flow.add_uses(memrw_cell_nodes[cell], memwr_cell->getPort(ID::DATA));
}
}
}
for (auto proc : module->processes) {
flow.add_node(proc.second);
for (auto sync : proc.second->syncs)
switch (sync->type) {
// Edge-type sync rules require pre-registration.
case RTLIL::STp:
case RTLIL::STn:
case RTLIL::STe:
register_edge_signal(sigmap, sync->signal, sync->type);
break;
// Level-type sync rules require no special handling.
case RTLIL::ST0:
case RTLIL::ST1:
case RTLIL::STa:
break;
case RTLIL::STg:
log_cmd_error("Global clock is not supported.\n");
// Handling of init-type sync rules is delegated to the `proc_init` pass, so we can use the wire
// attribute regardless of input.
case RTLIL::STi:
log_assert(false);
}
}
for (auto wire : module->wires()) {
if (!flow.is_elidable(wire)) continue;
if (wire->port_id != 0) continue;
if (wire->get_bool_attribute(ID::keep)) continue;
if (wire->name.begins_with("$") && !elide_internal) continue;
if (wire->name.begins_with("\\") && !elide_public) continue;
if (edge_wires[wire]) continue;
log_assert(flow.wire_comb_defs[wire].size() == 1);
elided_wires[wire] = **flow.wire_comb_defs[wire].begin();
}
dict<FlowGraph::Node*, pool<const RTLIL::Wire*>, hash_ptr_ops> node_defs;
for (auto wire_comb_def : flow.wire_comb_defs)
for (auto node : wire_comb_def.second)
node_defs[node].insert(wire_comb_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", log_id(module));
for (auto wire : feedback_wires)
log(" %s\n", log_id(wire));
}
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 (edge_wires[wire]) continue;
if (flow.wire_sync_defs.count(wire) > 0) continue;
localized_wires.insert(wire);
}
// For maximum performance, the state of the simulation (which is the same as the set of its double buffered
// wires, since using a singly buffered wire for any kind of state introduces a race condition) should contain
// no wires attached to combinatorial outputs. Feedback wires, by definition, make that impossible. However,
// it is possible that a design with no feedback arcs would end up with doubly buffered wires in such cases
// as a wire with multiple drivers where one of them is combinatorial and the other is synchronous. Such designs
// also require more than one delta cycle to converge.
pool<const RTLIL::Wire*> buffered_wires;
for (auto wire : module->wires()) {
if (flow.wire_comb_defs[wire].size() > 0 && !elided_wires.count(wire) && !localized_wires[wire]) {
if (!feedback_wires[wire])
buffered_wires.insert(wire);
}
}
if (!buffered_wires.empty()) {
has_buffered_wires = true;
log("Module `%s' contains buffered combinatorial wires:\n", log_id(module));
for (auto wire : buffered_wires)
log(" %s\n", log_id(wire));
}
eval_converges[module] = feedback_wires.empty() && buffered_wires.empty();
}
if (has_feedback_arcs || has_buffered_wires) {
// Although both non-feedback buffered combinatorial wires and apparent feedback wires may be eliminated
// by optimizing the design, if after `opt_clean -purge` there are any feedback wires remaining, it is very
// likely that these feedback wires are indicative of a true logic loop, so they get emphasized in the message.
const char *why_pessimistic = nullptr;
if (has_feedback_arcs)
why_pessimistic = "feedback wires";
else if (has_buffered_wires)
why_pessimistic = "buffered combinatorial wires";
log("\n");
log_warning("Design contains %s, which require delta cycles during evaluation.\n", why_pessimistic);
if (!max_opt_level)
log("Increasing the optimization level may eliminate %s from the design.\n", why_pessimistic);
}
}
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() && !module->has_attribute(ID(cxxrtl_blackbox)))
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;
log_push();
check_design(design, has_sync_init, has_packed_mem);
if (run_proc_flatten) {
Pass::call(design, "proc");
Pass::call(design, "flatten");
} else 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_opt_clean_purge)
Pass::call(design, "opt_clean -purge");
log_pop();
analyze_design(design);
}
};
struct CxxrtlBackend : public Backend {
static const int DEFAULT_OPT_LEVEL = 6;
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 that simulates the design. The generated code requires a driver\n");
log("that instantiates the design, toggles its clock, and interacts with its ports.\n");
log("\n");
log("The following driver may be used as an example for a design with a single clock\n");
log("driving rising edge triggered flip-flops:\n");
log("\n");
log(" #include \"top.cc\"\n");
log("\n");
log(" int main() {\n");
log(" cxxrtl_design::p_top top;\n");
log(" top.step();\n");
log(" while (1) {\n");
log(" /* user logic */\n");
log(" top.p_clk = value<1> {0u};\n");
log(" top.step();\n");
log(" top.p_clk = value<1> {1u};\n");
log(" top.step();\n");
log(" }\n");
log(" }\n");
log("\n");
log("Note that CXXRTL simulations, just like the hardware they are simulating, are\n");
log("subject to race conditions. If, in the example above, the user logic would run\n");
log("simultaneously with the rising edge of the clock, the design would malfunction.\n");
log("\n");
log("This backend supports replacing parts of the design with black boxes implemented\n");
log("in C++. If a module marked as a CXXRTL black box, its implementation is ignored,\n");
log("and the generated code consists only of an interface and a factory function.\n");
log("The driver must implement the factory function that creates an implementation of\n");
log("the black box, taking into account the parameters it is instantiated with.\n");
log("\n");
log("For example, the following Verilog code defines a CXXRTL black box interface for\n");
log("a synchronous debug sink:\n");
log("\n");
log(" (* cxxrtl_blackbox *)\n");
log(" module debug(...);\n");
log(" (* cxxrtl_edge = \"p\" *) input clk;\n");
log(" input en;\n");
log(" input [7:0] i_data;\n");
log(" (* cxxrtl_sync *) output [7:0] o_data;\n");
log(" endmodule\n");
log("\n");
log("For this HDL interface, this backend will generate the following C++ interface:\n");
log("\n");
log(" struct bb_p_debug : public module {\n");
log(" value<1> p_clk;\n");
log(" bool posedge_p_clk() const { /* ... */ }\n");
log(" value<1> p_en;\n");
log(" value<8> p_i_data;\n");
log(" wire<8> p_o_data;\n");
log("\n");
log(" bool eval() override;\n");
log(" bool commit() override;\n");
log("\n");
log(" static std::unique_ptr<bb_p_debug>\n");
log(" create(std::string name, metadata_map parameters, metadata_map attributes);\n");
log(" };\n");
log("\n");
log("The `create' function must be implemented by the driver. For example, it could\n");
log("always provide an implementation logging the values to standard error stream:\n");
log("\n");
log(" namespace cxxrtl_design {\n");
log("\n");
log(" struct stderr_debug : public bb_p_debug {\n");
log(" bool eval() override {\n");
log(" if (posedge_p_clk() && p_en)\n");
log(" fprintf(stderr, \"debug: %%02x\\n\", p_i_data.data[0]);\n");
log(" p_o_data.next = p_i_data;\n");
log(" return bb_p_debug::eval();\n");
log(" }\n");
log(" };\n");
log("\n");
log(" std::unique_ptr<bb_p_debug>\n");
log(" bb_p_debug::create(std::string name, cxxrtl::metadata_map parameters,\n");
log(" cxxrtl::metadata_map attributes) {\n");
log(" return std::make_unique<stderr_debug>();\n");
log(" }\n");
log("\n");
log(" }\n");
log("\n");
log("For complex applications of black boxes, it is possible to parameterize their\n");
log("port widths. For example, the following Verilog code defines a CXXRTL black box\n");
log("interface for a configurable width debug sink:\n");
log("\n");
log(" (* cxxrtl_blackbox, cxxrtl_template = \"WIDTH\" *)\n");
log(" module debug(...);\n");
log(" parameter WIDTH = 8;\n");
log(" (* cxxrtl_edge = \"p\" *) input clk;\n");
log(" input en;\n");
log(" (* cxxrtl_width = \"WIDTH\" *) input [WIDTH - 1:0] i_data;\n");
log(" (* cxxrtl_width = \"WIDTH\" *) output [WIDTH - 1:0] o_data;\n");
log(" endmodule\n");
log("\n");
log("For this parametric HDL interface, this backend will generate the following C++\n");
log("interface (only the differences are shown):\n");
log("\n");
log(" template<size_t WIDTH>\n");
log(" struct bb_p_debug : public module {\n");
log(" // ...\n");
log(" value<WIDTH> p_i_data;\n");
log(" wire<WIDTH> p_o_data;\n");
log(" // ...\n");
log(" static std::unique_ptr<bb_p_debug<WIDTH>>\n");
log(" create(std::string name, metadata_map parameters, metadata_map attributes);\n");
log(" };\n");
log("\n");
log("The `create' function must be implemented by the driver, specialized for every\n");
log("possible combination of template parameters. (Specialization is necessary to\n");
log("enable separate compilation of generated code and black box implementations.)\n");
log("\n");
log(" template<size_t SIZE>\n");
log(" struct stderr_debug : public bb_p_debug<SIZE> {\n");
log(" // ...\n");
log(" };\n");
log("\n");
log(" template<>\n");
log(" std::unique_ptr<bb_p_debug<8>>\n");
log(" bb_p_debug<8>::create(std::string name, cxxrtl::metadata_map parameters,\n");
log(" cxxrtl::metadata_map attributes) {\n");
log(" return std::make_unique<stderr_debug<8>>();\n");
log(" }\n");
log("\n");
log("The following attributes are recognized by this backend:\n");
log("\n");
log(" cxxrtl_blackbox\n");
log(" only valid on modules. if specified, the module contents are ignored,\n");
log(" and the generated code includes only the module interface and a factory\n");
log(" function, which will be called to instantiate the module.\n");
log("\n");
log(" cxxrtl_edge\n");
log(" only valid on inputs of black boxes. must be one of \"p\", \"n\", \"a\".\n");
log(" if specified on signal `clk`, the generated code includes edge detectors\n");
log(" `posedge_p_clk()` (if \"p\"), `negedge_p_clk()` (if \"n\"), or both (if\n");
log(" \"a\"), simplifying implementation of clocked black boxes.\n");
log("\n");
log(" cxxrtl_template\n");
log(" only valid on black boxes. must contain a space separated sequence of\n");
log(" identifiers that have a corresponding black box parameters. for each\n");
log(" of them, the generated code includes a `size_t` template parameter.\n");
log("\n");
log(" cxxrtl_width\n");
log(" only valid on ports of black boxes. must be a constant expression, which\n");
log(" is directly inserted into generated code.\n");
log("\n");
log(" cxxrtl_comb, cxxrtl_sync\n");
log(" only valid on outputs of black boxes. if specified, indicates that every\n");
log(" bit of the output port is driven, correspondingly, by combinatorial or\n");
log(" synchronous logic. this knowledge is used for scheduling optimizations.\n");
log(" if neither is specified, the output will be pessimistically treated as\n");
log(" driven by both combinatorial and synchronous logic.\n");
log("\n");
log("The following options are supported by this backend:\n");
log("\n");
log(" -header\n");
log(" generate separate interface (.h) and implementation (.cc) files.\n");
log(" if specified, the backend must be called with a filename, and filename\n");
log(" of the interface is derived from filename of the implementation.\n");
log(" otherwise, interface and implementation are generated together.\n");
log("\n");
log(" -namespace <ns-name>\n");
log(" place the generated code into namespace <ns-name>. if not specified,\n");
log(" \"cxxrtl_design\" is used.\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 `opt_clean -purge` first.\n");
log("\n");
log(" -O6\n");
log(" like -O5, and run `proc; flatten` 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;
CxxrtlWorker worker;
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;
}
if (args[argidx] == "-header") {
worker.split_intf = true;
continue;
}
if (args[argidx] == "-namespace" && argidx+1 < args.size()) {
worker.design_ns = args[++argidx];
continue;
}
break;
}
extra_args(f, filename, args, argidx);
switch (opt_level) {
case 6:
worker.max_opt_level = true;
worker.run_proc_flatten = true;
YS_FALLTHROUGH
case 5:
worker.run_opt_clean_purge = true;
YS_FALLTHROUGH
case 4:
worker.localize_public = true;
YS_FALLTHROUGH
case 3:
worker.elide_public = true;
YS_FALLTHROUGH
case 2:
worker.localize_internal = true;
YS_FALLTHROUGH
case 1:
worker.elide_internal = true;
YS_FALLTHROUGH
case 0:
break;
default:
log_cmd_error("Invalid optimization level %d.\n", opt_level);
}
std::ofstream intf_f;
if (worker.split_intf) {
if (filename == "<stdout>")
log_cmd_error("Option -header must be used with a filename.\n");
worker.intf_filename = filename.substr(0, filename.rfind('.')) + ".h";
intf_f.open(worker.intf_filename, std::ofstream::trunc);
if (intf_f.fail())
log_cmd_error("Can't open file `%s' for writing: %s\n",
worker.intf_filename.c_str(), strerror(errno));
worker.intf_f = &intf_f;
}
worker.impl_f = f;
worker.prepare_design(design);
worker.dump_design(design);
}
} CxxrtlBackend;
PRIVATE_NAMESPACE_END
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