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yosys/backends/cxxrtl/cxxrtl_backend.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/mem.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_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), ID($modfloor));
}
bool is_extending_cell(RTLIL::IdString type)
{
return !type.in(
ID($logic_not), ID($logic_and), ID($logic_or),
ID($reduce_and), ID($reduce_or), ID($reduce_xor), ID($reduce_xnor), ID($reduce_bool));
}
bool is_inlinable_cell(RTLIL::IdString type)
{
return is_unary_cell(type) || is_binary_cell(type) || type.in(
ID($mux), ID($concat), ID($slice), ID($pmux), ID($bmux), ID($demux));
}
bool is_ff_cell(RTLIL::IdString type)
{
return type.in(
ID($dff), ID($dffe), ID($sdff), ID($sdffe), ID($sdffce),
ID($adff), ID($adffe), ID($dffsr), ID($dffsre),
ID($aldff), ID($aldffe),
ID($dlatch), ID($adlatch), ID($dlatchsr), ID($sr));
}
bool is_internal_cell(RTLIL::IdString type)
{
return !type.isPublic() && !type.begins_with("$paramod");
}
bool is_effectful_cell(RTLIL::IdString type)
{
return type.isPublic();
}
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));
}
bool is_memwr_process(const RTLIL::Process *process)
{
for (auto sync : process->syncs)
if (!sync->mem_write_actions.empty())
return true;
return false;
}
enum class CxxrtlPortType {
UNKNOWN = 0, // or mixed comb/sync
COMB = 1,
SYNC = 2,
};
CxxrtlPortType cxxrtl_port_type(RTLIL::Module *module, RTLIL::IdString port)
{
RTLIL::Wire *output_wire = module->wire(port);
log_assert(output_wire != nullptr);
bool is_comb = output_wire->get_bool_attribute(ID(cxxrtl_comb));
bool is_sync = 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(module), log_signal(output_wire));
else if (is_comb)
return CxxrtlPortType::COMB;
else if (is_sync)
return CxxrtlPortType::SYNC;
return CxxrtlPortType::UNKNOWN;
}
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;
return cxxrtl_port_type(cell_module, port);
}
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_SYNC,
PROCESS_CASE,
MEM_RDPORT,
MEM_WRPORTS,
};
Type type;
RTLIL::SigSig connect = {};
const RTLIL::Cell *cell = nullptr;
const RTLIL::Process *process = nullptr;
const Mem *mem = nullptr;
int portidx;
};
std::vector<Node*> nodes;
dict<const RTLIL::Wire*, pool<Node*, hash_ptr_ops>> wire_comb_defs, wire_sync_defs, wire_uses;
dict<Node*, pool<const RTLIL::Wire*>, hash_ptr_ops> node_comb_defs, node_sync_defs, node_uses;
dict<const RTLIL::Wire*, bool> wire_def_inlinable;
dict<const RTLIL::Wire*, dict<Node*, bool, hash_ptr_ops>> wire_use_inlinable;
dict<RTLIL::SigBit, bool> bit_has_state;
~FlowGraph()
{
for (auto node : nodes)
delete node;
}
void add_defs(Node *node, const RTLIL::SigSpec &sig, bool is_ff, bool inlinable)
{
for (auto chunk : sig.chunks())
if (chunk.wire) {
if (is_ff) {
// A sync def means that a wire holds design state because it is driven directly by
// a flip-flop output. Such a wire can never be unbuffered.
wire_sync_defs[chunk.wire].insert(node);
node_sync_defs[node].insert(chunk.wire);
} else {
// A comb def means that a wire doesn't hold design state. It might still be connected,
// indirectly, to a flip-flop output.
wire_comb_defs[chunk.wire].insert(node);
node_comb_defs[node].insert(chunk.wire);
}
}
for (auto bit : sig.bits())
bit_has_state[bit] |= is_ff;
// Only comb defs of an entire wire in the right order can be inlined.
if (!is_ff && sig.is_wire()) {
// Only a single def of a wire can be inlined. (Multiple defs of a wire are unsound, but we
// handle them anyway to avoid assertion failures later.)
if (!wire_def_inlinable.count(sig.as_wire()))
wire_def_inlinable[sig.as_wire()] = inlinable;
else
wire_def_inlinable[sig.as_wire()] = false;
}
}
void add_uses(Node *node, const RTLIL::SigSpec &sig)
{
for (auto chunk : sig.chunks())
if (chunk.wire) {
wire_uses[chunk.wire].insert(node);
node_uses[node].insert(chunk.wire);
// Only a single use of an entire wire in the right order can be inlined. (But the use can include
// other chunks.) This is tracked per-node because a wire used by multiple nodes can still be inlined
// if all but one of those nodes is dead.
if (!wire_use_inlinable[chunk.wire].count(node))
wire_use_inlinable[chunk.wire][node] = true;
else
wire_use_inlinable[chunk.wire][node] = false;
}
}
bool is_inlinable(const RTLIL::Wire *wire) const
{
// Can the wire be inlined at all?
if (wire_def_inlinable.count(wire))
return wire_def_inlinable.at(wire);
return false;
}
bool is_inlinable(const RTLIL::Wire *wire, const pool<Node*, hash_ptr_ops> &nodes) const
{
// Can the wire be inlined, knowing that the given nodes are reachable?
if (nodes.size() != 1)
return false;
Node *node = *nodes.begin();
log_assert(node_uses.at(node).count(wire));
if (is_inlinable(wire) && wire_use_inlinable.count(wire) && wire_use_inlinable.at(wire).count(node))
return wire_use_inlinable.at(wire).at(node);
return false;
}
// Connections
void add_connect_defs_uses(Node *node, const RTLIL::SigSig &conn)
{
add_defs(node, conn.first, /*is_ff=*/false, /*inlinable=*/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
// expressible 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 inlinability below.
add_defs(node, conn.second, /*is_ff=*/false, /*inlinable=*/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_inlinable_cell(cell->type))
add_defs(node, conn.second, /*is_ff=*/false, /*inlinable=*/true);
else if (is_ff_cell(cell->type))
add_defs(node, conn.second, /*is_ff=*/true, /*inlinable=*/false);
else if (is_internal_cell(cell->type))
add_defs(node, conn.second, /*is_ff=*/false, /*inlinable=*/false);
else if (!is_cxxrtl_sync_port(cell, conn.first)) {
// Although at first it looks like outputs of user-defined cells may always be inlined, the reality is
// more complex. Fully sync outputs produce no defs and so don't participate in inlining. Fully comb
// outputs are assigned in a different way depending on whether the cell's eval() immediately converged.
// Unknown/mixed outputs could be inlined, but should be rare in practical designs and don't justify
// the infrastructure required to inline outputs of cells with many of them.
add_defs(node, conn.second, /*is_ff=*/false, /*inlinable=*/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_rule_defs_uses(Node *node, const RTLIL::CaseRule *case_)
{
for (auto &action : case_->actions) {
add_defs(node, action.first, /*is_ff=*/false, /*inlinable=*/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_rule_defs_uses(node, sub_case);
}
}
}
void add_sync_rules_defs_uses(Node *node, const RTLIL::Process *process)
{
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_ff=*/true, /*inlinable=*/false);
else
add_defs(node, action.first, /*is_ff=*/false, /*inlinable=*/false);
add_uses(node, action.second);
}
for (auto &memwr : sync->mem_write_actions) {
add_uses(node, memwr.address);
add_uses(node, memwr.data);
add_uses(node, memwr.enable);
}
}
}
Node *add_node(const RTLIL::Process *process)
{
Node *node = new Node;
node->type = Node::Type::PROCESS_SYNC;
node->process = process;
nodes.push_back(node);
add_sync_rules_defs_uses(node, process);
node = new Node;
node->type = Node::Type::PROCESS_CASE;
node->process = process;
nodes.push_back(node);
add_case_rule_defs_uses(node, &process->root_case);
return node;
}
// Memories
void add_node(const Mem *mem) {
for (int i = 0; i < GetSize(mem->rd_ports); i++) {
auto &port = mem->rd_ports[i];
Node *node = new Node;
node->type = Node::Type::MEM_RDPORT;
node->mem = mem;
node->portidx = i;
nodes.push_back(node);
add_defs(node, port.data, /*is_ff=*/port.clk_enable, /*inlinable=*/false);
add_uses(node, port.clk);
add_uses(node, port.en);
add_uses(node, port.arst);
add_uses(node, port.srst);
add_uses(node, port.addr);
bool transparent = false;
for (int j = 0; j < GetSize(mem->wr_ports); j++) {
auto &wrport = mem->wr_ports[j];
if (port.transparency_mask[j]) {
// Our implementation of transparent read ports reads en, addr and data from every write port
// the read port is transparent with.
add_uses(node, wrport.en);
add_uses(node, wrport.addr);
add_uses(node, wrport.data);
transparent = true;
}
}
// Also we read the read address twice in this case (prevent inlining).
if (transparent)
add_uses(node, port.addr);
}
if (!mem->wr_ports.empty()) {
Node *node = new Node;
node->type = Node::Type::MEM_WRPORTS;
node->mem = mem;
nodes.push_back(node);
for (auto &port : mem->wr_ports) {
add_uses(node, port.clk);
add_uses(node, port.en);
add_uses(node, port.addr);
add_uses(node, port.data);
}
}
}
};
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);
if (curr == std::string::npos) {
std::string part = str.substr(prev);
if (!part.empty()) result.push_back(part);
break;
} else {
std::string part = str.substr(prev, curr - prev);
if (!part.empty()) result.push_back(part);
prev = curr + 1;
}
}
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;
}
template<class T>
std::string get_hdl_name(T *object)
{
if (object->has_attribute(ID::hdlname))
return object->get_string_attribute(ID::hdlname);
else
return object->name.str().substr(1);
}
struct WireType {
enum Type {
// Non-referenced wire; is not a part of the design.
UNUSED,
// Double-buffered wire; is a class member, and holds design state.
BUFFERED,
// Single-buffered wire; is a class member, but holds no state.
MEMBER,
// Single-buffered wire; is a class member, and is computed on demand.
OUTLINE,
// Local wire; is a local variable in eval method.
LOCAL,
// Inline wire; is an unnamed temporary in eval method.
INLINE,
// Alias wire; is replaced with aliasee, except in debug info.
ALIAS,
// Const wire; is replaced with constant, except in debug info.
CONST,
};
Type type = UNUSED;
const RTLIL::Cell *cell_subst = nullptr; // for INLINE
RTLIL::SigSpec sig_subst = {}; // for INLINE, ALIAS, and CONST
WireType() = default;
WireType(Type type) : type(type) {
log_assert(type == UNUSED || type == BUFFERED || type == MEMBER || type == OUTLINE || type == LOCAL);
}
WireType(Type type, const RTLIL::Cell *cell) : type(type), cell_subst(cell) {
log_assert(type == INLINE && is_inlinable_cell(cell->type));
}
WireType(Type type, RTLIL::SigSpec sig) : type(type), sig_subst(sig) {
log_assert(type == INLINE || (type == ALIAS && sig.is_wire()) || (type == CONST && sig.is_fully_const()));
}
bool is_buffered() const { return type == BUFFERED; }
bool is_member() const { return type == BUFFERED || type == MEMBER || type == OUTLINE; }
bool is_outline() const { return type == OUTLINE; }
bool is_named() const { return is_member() || type == LOCAL; }
bool is_local() const { return type == LOCAL || type == INLINE; }
bool is_exact() const { return type == ALIAS || type == CONST; }
};
// Tests for a SigSpec that is a valid clock input, clocks have to have a backing wire and be a single bit
// using this instead of sig.is_wire() solves issues when the clock is a slice instead of a full wire
bool is_valid_clock(const RTLIL::SigSpec& sig) {
return sig.is_chunk() && sig.is_bit() && sig[0].wire;
}
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 print_wire_types = false;
bool print_debug_wire_types = false;
bool run_hierarchy = false;
bool run_flatten = false;
bool run_proc = false;
bool unbuffer_internal = false;
bool unbuffer_public = false;
bool localize_internal = false;
bool localize_public = false;
bool inline_internal = false;
bool inline_public = false;
bool debug_info = false;
bool debug_member = false;
bool debug_alias = false;
bool debug_eval = false;
std::ostringstream f;
std::string indent;
int temporary = 0;
dict<const RTLIL::Module*, SigMap> sigmaps;
dict<const RTLIL::Module*, std::vector<Mem>> mod_memories;
pool<std::pair<const RTLIL::Module*, RTLIL::IdString>> writable_memories;
pool<const RTLIL::Wire*> edge_wires;
dict<const RTLIL::Wire*, RTLIL::Const> wire_init;
dict<RTLIL::SigBit, RTLIL::SyncType> edge_types;
dict<const RTLIL::Module*, std::vector<FlowGraph::Node>> schedule, debug_schedule;
dict<const RTLIL::Wire*, WireType> wire_types, debug_wire_types;
dict<RTLIL::SigBit, bool> bit_has_state;
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 Mem *mem)
{
return mangle_memory_name(mem->memid);
}
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(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, bool for_debug = false)
{
if (chunk.wire == NULL) {
dump_const(chunk.data, chunk.width, chunk.offset);
return false;
} else {
const auto &wire_type = (for_debug ? debug_wire_types : wire_types)[chunk.wire];
switch (wire_type.type) {
case WireType::BUFFERED:
f << mangle(chunk.wire) << (is_lhs ? ".next" : ".curr");
break;
case WireType::MEMBER:
case WireType::LOCAL:
case WireType::OUTLINE:
f << mangle(chunk.wire);
break;
case WireType::INLINE:
log_assert(!is_lhs);
if (wire_type.cell_subst != nullptr) {
dump_cell_expr(wire_type.cell_subst, for_debug);
break;
}
YS_FALLTHROUGH
case WireType::ALIAS:
case WireType::CONST:
log_assert(!is_lhs);
return dump_sigspec(wire_type.sig_subst.extract(chunk.offset, chunk.width), is_lhs, for_debug);
case WireType::UNUSED:
log_assert(is_lhs);
f << "value<" << chunk.width << ">()";
return false;
}
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, bool for_debug = false)
{
if (sig.empty()) {
f << "value<0>()";
return false;
} else if (sig.is_chunk()) {
return dump_sigchunk(sig.as_chunk(), is_lhs, for_debug);
} else {
bool first = true;
auto chunks = sig.chunks();
for (auto it = chunks.rbegin(); it != chunks.rend(); it++) {
if (!first)
f << ".concat(";
bool is_complex = dump_sigchunk(*it, is_lhs, for_debug);
if (!is_lhs && it->width == 1) {
size_t repeat = 1;
while ((it + repeat) != chunks.rend() && *(it + repeat) == *it)
repeat++;
if (repeat > 1) {
if (is_complex)
f << ".val()";
f << ".repeat<" << repeat << ">()";
}
it += repeat - 1;
}
if (!first)
f << ")";
first = false;
}
return true;
}
}
void dump_sigspec_lhs(const RTLIL::SigSpec &sig, bool for_debug = false)
{
dump_sigspec(sig, /*is_lhs=*/true, for_debug);
}
void dump_sigspec_rhs(const RTLIL::SigSpec &sig, bool for_debug = false)
{
// 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, for_debug);
if (is_complex)
f << ".val()";
}
void dump_inlined_cells(const std::vector<const RTLIL::Cell*> &cells)
{
if (cells.empty()) {
f << indent << "// connection\n";
} else if (cells.size() == 1) {
dump_attrs(cells.front());
f << indent << "// cell " << cells.front()->name.str() << "\n";
} else {
f << indent << "// cells";
for (auto cell : cells)
f << " " << cell->name.str();
f << "\n";
}
}
void collect_sigspec_rhs(const RTLIL::SigSpec &sig, bool for_debug, std::vector<const RTLIL::Cell*> &cells)
{
for (auto chunk : sig.chunks()) {
if (!chunk.wire)
continue;
const auto &wire_type = wire_types[chunk.wire];
switch (wire_type.type) {
case WireType::INLINE:
if (wire_type.cell_subst != nullptr) {
collect_cell_eval(wire_type.cell_subst, for_debug, cells);
break;
}
YS_FALLTHROUGH
case WireType::ALIAS:
collect_sigspec_rhs(wire_type.sig_subst, for_debug, cells);
break;
default:
break;
}
}
}
void dump_connect_expr(const RTLIL::SigSig &conn, bool for_debug = false)
{
dump_sigspec_rhs(conn.second, for_debug);
}
void dump_connect(const RTLIL::SigSig &conn, bool for_debug = false)
{
std::vector<const RTLIL::Cell*> inlined_cells;
collect_sigspec_rhs(conn.second, for_debug, inlined_cells);
dump_inlined_cells(inlined_cells);
f << indent;
dump_sigspec_lhs(conn.first, for_debug);
f << " = ";
dump_connect_expr(conn, for_debug);
f << ";\n";
}
void collect_connect(const RTLIL::SigSig &conn, bool for_debug, std::vector<const RTLIL::Cell*> &cells)
{
collect_sigspec_rhs(conn.second, for_debug, cells);
}
void dump_cell_sync(const RTLIL::Cell *cell, bool for_debug = false)
{
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, for_debug);
f << " = " << mangle(cell) << access << mangle_wire_name(conn.first) << ".curr;\n";
}
}
void dump_cell_expr(const RTLIL::Cell *cell, bool for_debug = false)
{
// Unary cells
if (is_unary_cell(cell->type)) {
f << cell->type.substr(1);
if (is_extending_cell(cell->type))
f << '_' << (cell->getParam(ID::A_SIGNED).as_bool() ? 's' : 'u');
f << "<" << cell->getParam(ID::Y_WIDTH).as_int() << ">(";
dump_sigspec_rhs(cell->getPort(ID::A), for_debug);
f << ")";
// Binary cells
} else if (is_binary_cell(cell->type)) {
f << cell->type.substr(1);
if (is_extending_cell(cell->type))
f << '_' << (cell->getParam(ID::A_SIGNED).as_bool() ? 's' : 'u') <<
(cell->getParam(ID::B_SIGNED).as_bool() ? 's' : 'u');
f << "<" << cell->getParam(ID::Y_WIDTH).as_int() << ">(";
dump_sigspec_rhs(cell->getPort(ID::A), for_debug);
f << ", ";
dump_sigspec_rhs(cell->getPort(ID::B), for_debug);
f << ")";
// Muxes
} else if (cell->type == ID($mux)) {
f << "(";
dump_sigspec_rhs(cell->getPort(ID::S), for_debug);
f << " ? ";
dump_sigspec_rhs(cell->getPort(ID::B), for_debug);
f << " : ";
dump_sigspec_rhs(cell->getPort(ID::A), for_debug);
f << ")";
// Parallel (one-hot) muxes
} else if (cell->type == ID($pmux)) {
int width = cell->getParam(ID::WIDTH).as_int();
int s_width = cell->getParam(ID::S_WIDTH).as_int();
for (int part = 0; part < s_width; part++) {
f << "(";
dump_sigspec_rhs(cell->getPort(ID::S).extract(part), for_debug);
f << " ? ";
dump_sigspec_rhs(cell->getPort(ID::B).extract(part * width, width), for_debug);
f << " : ";
}
dump_sigspec_rhs(cell->getPort(ID::A), for_debug);
for (int part = 0; part < s_width; part++) {
f << ")";
}
// Big muxes
} else if (cell->type == ID($bmux)) {
dump_sigspec_rhs(cell->getPort(ID::A), for_debug);
f << ".bmux<";
f << cell->getParam(ID::WIDTH).as_int();
f << ">(";
dump_sigspec_rhs(cell->getPort(ID::S), for_debug);
f << ").val()";
// Demuxes
} else if (cell->type == ID($demux)) {
dump_sigspec_rhs(cell->getPort(ID::A), for_debug);
f << ".demux<";
f << GetSize(cell->getPort(ID::Y));
f << ">(";
dump_sigspec_rhs(cell->getPort(ID::S), for_debug);
f << ").val()";
// Concats
} else if (cell->type == ID($concat)) {
dump_sigspec_rhs(cell->getPort(ID::B), for_debug);
f << ".concat(";
dump_sigspec_rhs(cell->getPort(ID::A), for_debug);
f << ").val()";
// Slices
} else if (cell->type == ID($slice)) {
dump_sigspec_rhs(cell->getPort(ID::A), for_debug);
f << ".slice<";
f << cell->getParam(ID::OFFSET).as_int() + cell->getParam(ID::Y_WIDTH).as_int() - 1;
f << ",";
f << cell->getParam(ID::OFFSET).as_int();
f << ">().val()";
} else {
log_assert(false);
}
}
void dump_cell_eval(const RTLIL::Cell *cell, bool for_debug = false)
{
std::vector<const RTLIL::Cell*> inlined_cells;
collect_cell_eval(cell, for_debug, inlined_cells);
dump_inlined_cells(inlined_cells);
// Elidable cells
if (is_inlinable_cell(cell->type)) {
f << indent;
dump_sigspec_lhs(cell->getPort(ID::Y), for_debug);
f << " = ";
dump_cell_expr(cell, for_debug);
f << ";\n";
// Flip-flops
} else if (is_ff_cell(cell->type)) {
log_assert(!for_debug);
// Clocks might be slices of larger signals but should only ever be single bit
if (cell->hasPort(ID::CLK) && is_valid_clock(cell->getPort(ID::CLK))) {
// Edge-sensitive logic
RTLIL::SigBit clk_bit = cell->getPort(ID::CLK)[0];
clk_bit = sigmaps[clk_bit.wire->module](clk_bit);
if (clk_bit.wire) {
f << indent << "if (" << (cell->getParam(ID::CLK_POLARITY).as_bool() ? "posedge_" : "negedge_")
<< mangle(clk_bit) << ") {\n";
} else {
f << indent << "if (false) {\n";
}
inc_indent();
if (cell->hasPort(ID::EN)) {
f << indent << "if (";
dump_sigspec_rhs(cell->getPort(ID::EN));
f << " == value<1> {" << cell->getParam(ID::EN_POLARITY).as_bool() << "u}) {\n";
inc_indent();
}
f << indent;
dump_sigspec_lhs(cell->getPort(ID::Q));
f << " = ";
dump_sigspec_rhs(cell->getPort(ID::D));
f << ";\n";
if (cell->hasPort(ID::EN) && cell->type != ID($sdffce)) {
dec_indent();
f << indent << "}\n";
}
if (cell->hasPort(ID::SRST)) {
f << indent << "if (";
dump_sigspec_rhs(cell->getPort(ID::SRST));
f << " == value<1> {" << cell->getParam(ID::SRST_POLARITY).as_bool() << "u}) {\n";
inc_indent();
f << indent;
dump_sigspec_lhs(cell->getPort(ID::Q));
f << " = ";
dump_const(cell->getParam(ID::SRST_VALUE));
f << ";\n";
dec_indent();
f << indent << "}\n";
}
if (cell->hasPort(ID::EN) && cell->type == ID($sdffce)) {
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::ALOAD)) {
// Asynchronous load
f << indent << "if (";
dump_sigspec_rhs(cell->getPort(ID::ALOAD));
f << " == value<1> {" << cell->getParam(ID::ALOAD_POLARITY).as_bool() << "u}) {\n";
inc_indent();
f << indent;
dump_sigspec_lhs(cell->getPort(ID::Q));
f << " = ";
dump_sigspec_rhs(cell->getPort(ID::AD));
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";
}
// 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(!for_debug);
log_assert(cell->known());
bool buffered_inputs = false;
const char *access = is_cxxrtl_blackbox_cell(cell) ? "->" : ".";
for (auto conn : cell->connections())
if (cell->input(conn.first)) {
RTLIL::Module *cell_module = cell->module->design->module(cell->type);
log_assert(cell_module != nullptr && cell_module->wire(conn.first));
RTLIL::Wire *cell_module_wire = cell_module->wire(conn.first);
f << indent << mangle(cell) << access << mangle_wire_name(conn.first);
if (!is_cxxrtl_blackbox_cell(cell) && wire_types[cell_module_wire].is_buffered()) {
buffered_inputs = true;
f << ".next";
}
f << " = ";
dump_sigspec_rhs(conn.second);
f << ";\n";
if (getenv("CXXRTL_VOID_MY_WARRANTY") && conn.second.is_wire()) {
// 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.
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";
}
}
}
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.)
//
// 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";
}
}
};
if (buffered_inputs) {
// If we have any buffered inputs, there's no chance of converging immediately.
f << indent << mangle(cell) << access << "eval();\n";
f << indent << "converged = false;\n";
assign_from_outputs(/*cell_converged=*/false);
} else {
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 collect_cell_eval(const RTLIL::Cell *cell, bool for_debug, std::vector<const RTLIL::Cell*> &cells)
{
cells.push_back(cell);
for (auto port : cell->connections())
if (cell->input(port.first))
collect_sigspec_rhs(port.second, for_debug, cells);
}
void dump_assign(const RTLIL::SigSig &sigsig, bool for_debug = false)
{
f << indent;
dump_sigspec_lhs(sigsig.first, for_debug);
f << " = ";
dump_sigspec_rhs(sigsig.second, for_debug);
f << ";\n";
}
void dump_case_rule(const RTLIL::CaseRule *rule, bool for_debug = false)
{
for (auto action : rule->actions)
dump_assign(action, for_debug);
for (auto switch_ : rule->switches)
dump_switch_rule(switch_, for_debug);
}
void dump_switch_rule(const RTLIL::SwitchRule *rule, bool for_debug = false)
{
// 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, for_debug);
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, for_debug);
} 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_, for_debug);
dec_indent();
}
f << indent << "}\n";
}
void dump_process_case(const RTLIL::Process *proc, bool for_debug = false)
{
dump_attrs(proc);
f << indent << "// process " << proc->name.str() << " case\n";
// The case attributes (for root case) are always empty.
log_assert(proc->root_case.attributes.empty());
dump_case_rule(&proc->root_case, for_debug);
}
void dump_process_syncs(const RTLIL::Process *proc, bool for_debug = false)
{
dump_attrs(proc);
f << indent << "// process " << proc->name.str() << " syncs\n";
for (auto sync : proc->syncs) {
log_assert(!for_debug || sync->type == RTLIL::STa);
RTLIL::SigBit sync_bit;
if (!sync->signal.empty()) {
sync_bit = sync->signal[0];
sync_bit = sigmaps[sync_bit.wire->module](sync_bit);
if (!sync_bit.is_wire())
continue; // a clock, or more commonly a reset, can be tied to a constant driver
}
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, for_debug);
for (auto &memwr : sync->mem_write_actions) {
RTLIL::Memory *memory = proc->module->memories.at(memwr.memid);
std::string valid_index_temp = fresh_temporary();
f << indent << "auto " << valid_index_temp << " = memory_index(";
dump_sigspec_rhs(memwr.address);
f << ", " << memory->start_offset << ", " << memory->size << ");\n";
// See below 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 << "CXXRTL_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(memwr.data);
f << ", ";
dump_sigspec_rhs(memwr.enable);
f << ");\n";
dec_indent();
f << indent << "}\n";
}
dec_indent();
f << indent << "}\n";
}
}
}
void dump_mem_rdport(const Mem *mem, int portidx, bool for_debug = false)
{
auto &port = mem->rd_ports[portidx];
dump_attrs(&port);
f << indent << "// memory " << mem->memid.str() << " read port " << portidx << "\n";
if (port.clk_enable) {
log_assert(!for_debug);
RTLIL::SigBit clk_bit = port.clk[0];
clk_bit = sigmaps[clk_bit.wire->module](clk_bit);
if (clk_bit.wire) {
f << indent << "if (" << (port.clk_polarity ? "posedge_" : "negedge_")
<< mangle(clk_bit) << ") {\n";
} else {
f << indent << "if (false) {\n";
}
inc_indent();
}
std::vector<const RTLIL::Cell*> inlined_cells_addr;
collect_sigspec_rhs(port.addr, for_debug, inlined_cells_addr);
if (!inlined_cells_addr.empty())
dump_inlined_cells(inlined_cells_addr);
std::string valid_index_temp = fresh_temporary();
f << indent << "auto " << valid_index_temp << " = memory_index(";
// Almost all non-elidable cells cannot appear in debug_eval(), but $memrd is an exception; asynchronous
// memory read ports can.
dump_sigspec_rhs(port.addr, for_debug);
f << ", " << mem->start_offset << ", " << mem->size << ");\n";
bool has_enable = port.clk_enable && !port.en.is_fully_ones();
if (has_enable) {
std::vector<const RTLIL::Cell*> inlined_cells_en;
collect_sigspec_rhs(port.en, for_debug, inlined_cells_en);
if (!inlined_cells_en.empty())
dump_inlined_cells(inlined_cells_en);
f << indent << "if (";
dump_sigspec_rhs(port.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 -DCXXRTL_NDEBUG
// not only 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 << "CXXRTL_ASSERT(" << valid_index_temp << ".valid && \"out of bounds read\");\n";
f << indent << "if(" << valid_index_temp << ".valid) {\n";
inc_indent();
if (!mem->wr_ports.empty()) {
std::string lhs_temp = fresh_temporary();
f << indent << "value<" << mem->width << "> " << lhs_temp << " = "
<< mangle(mem) << "[" << valid_index_temp << ".index];\n";
bool transparent = false;
for (auto bit : port.transparency_mask)
if (bit)
transparent = true;
if (transparent) {
std::string addr_temp = fresh_temporary();
f << indent << "const value<" << port.addr.size() << "> &" << addr_temp << " = ";
dump_sigspec_rhs(port.addr);
f << ";\n";
for (int i = 0; i < GetSize(mem->wr_ports); i++) {
auto &wrport = mem->wr_ports[i];
if (!port.transparency_mask[i])
continue;
f << indent << "if (" << addr_temp << " == ";
dump_sigspec_rhs(wrport.addr);
f << ") {\n";
inc_indent();
f << indent << lhs_temp << " = " << lhs_temp;
f << ".update(";
dump_sigspec_rhs(wrport.data);
f << ", ";
dump_sigspec_rhs(wrport.en);
f << ");\n";
dec_indent();
f << indent << "}\n";
}
}
f << indent;
dump_sigspec_lhs(port.data);
f << " = " << lhs_temp << ";\n";
} else {
f << indent;
dump_sigspec_lhs(port.data);
f << " = " << mangle(mem) << "[" << valid_index_temp << ".index];\n";
}
dec_indent();
f << indent << "} else {\n";
inc_indent();
f << indent;
dump_sigspec_lhs(port.data);
f << " = value<" << mem->width << "> {};\n";
dec_indent();
f << indent << "}\n";
if (has_enable && !port.ce_over_srst) {
dec_indent();
f << indent << "}\n";
}
if (port.srst != State::S0) {
// Synchronous reset
std::vector<const RTLIL::Cell*> inlined_cells_srst;
collect_sigspec_rhs(port.srst, for_debug, inlined_cells_srst);
if (!inlined_cells_srst.empty())
dump_inlined_cells(inlined_cells_srst);
f << indent << "if (";
dump_sigspec_rhs(port.srst);
f << " == value<1> {1u}) {\n";
inc_indent();
f << indent;
dump_sigspec_lhs(port.data);
f << " = ";
dump_const(port.srst_value);
f << ";\n";
dec_indent();
f << indent << "}\n";
}
if (has_enable && port.ce_over_srst) {
dec_indent();
f << indent << "}\n";
}
if (port.clk_enable) {
dec_indent();
f << indent << "}\n";
}
if (port.arst != State::S0) {
// Asynchronous reset
std::vector<const RTLIL::Cell*> inlined_cells_arst;
collect_sigspec_rhs(port.arst, for_debug, inlined_cells_arst);
if (!inlined_cells_arst.empty())
dump_inlined_cells(inlined_cells_arst);
f << indent << "if (";
dump_sigspec_rhs(port.arst);
f << " == value<1> {1u}) {\n";
inc_indent();
f << indent;
dump_sigspec_lhs(port.data);
f << " = ";
dump_const(port.arst_value);
f << ";\n";
dec_indent();
f << indent << "}\n";
}
}
void dump_mem_wrports(const Mem *mem, bool for_debug = false)
{
log_assert(!for_debug);
for (int portidx = 0; portidx < GetSize(mem->wr_ports); portidx++) {
auto &port = mem->wr_ports[portidx];
dump_attrs(&port);
f << indent << "// memory " << mem->memid.str() << " write port " << portidx << "\n";
if (port.clk_enable) {
RTLIL::SigBit clk_bit = port.clk[0];
clk_bit = sigmaps[clk_bit.wire->module](clk_bit);
if (clk_bit.wire) {
f << indent << "if (" << (port.clk_polarity ? "posedge_" : "negedge_")
<< mangle(clk_bit) << ") {\n";
} else {
f << indent << "if (false) {\n";
}
inc_indent();
}
std::vector<const RTLIL::Cell*> inlined_cells_addr;
collect_sigspec_rhs(port.addr, for_debug, inlined_cells_addr);
if (!inlined_cells_addr.empty())
dump_inlined_cells(inlined_cells_addr);
std::string valid_index_temp = fresh_temporary();
f << indent << "auto " << valid_index_temp << " = memory_index(";
dump_sigspec_rhs(port.addr);
f << ", " << mem->start_offset << ", " << mem->size << ");\n";
// 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 << "CXXRTL_ASSERT(" << valid_index_temp << ".valid && \"out of bounds write\");\n";
f << indent << "if (" << valid_index_temp << ".valid) {\n";
inc_indent();
std::vector<const RTLIL::Cell*> inlined_cells;
collect_sigspec_rhs(port.data, for_debug, inlined_cells);
collect_sigspec_rhs(port.en, for_debug, inlined_cells);
if (!inlined_cells.empty())
dump_inlined_cells(inlined_cells);
f << indent << mangle(mem) << ".update(" << valid_index_temp << ".index, ";
dump_sigspec_rhs(port.data);
f << ", ";
dump_sigspec_rhs(port.en);
f << ", " << portidx << ");\n";
dec_indent();
f << indent << "}\n";
if (port.clk_enable) {
dec_indent();
f << indent << "}\n";
}
}
}
void dump_wire(const RTLIL::Wire *wire, bool is_local)
{
const auto &wire_type = wire_types[wire];
if (!wire_type.is_named() || wire_type.is_local() != is_local)
return;
dump_attrs(wire);
f << indent;
if (wire->port_input && wire->port_output)
f << "/*inout*/ ";
else if (wire->port_input)
f << "/*input*/ ";
else if (wire->port_output)
f << "/*output*/ ";
f << (wire_type.is_buffered() ? "wire" : "value");
if (wire->module->has_attribute(ID(cxxrtl_blackbox)) && wire->has_attribute(ID(cxxrtl_width))) {
f << "<" << wire->get_string_attribute(ID(cxxrtl_width)) << ">";
} else {
f << "<" << wire->width << ">";
}
f << " " << mangle(wire) << ";\n";
if (edge_wires[wire]) {
if (!wire_type.is_buffered()) {
f << indent << "value<" << wire->width << "> prev_" << mangle(wire) << ";\n";
}
for (auto edge_type : edge_types) {
if (edge_type.first.wire == wire) {
std::string prev, next;
if (!wire_type.is_buffered()) {
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_debug_wire(const RTLIL::Wire *wire, bool is_local)
{
const auto &wire_type = wire_types[wire];
if (wire_type.is_member())
return;
const auto &debug_wire_type = debug_wire_types[wire];
if (!debug_wire_type.is_named() || debug_wire_type.is_local() != is_local)
return;
dump_attrs(wire);
f << indent;
if (debug_wire_type.is_outline())
f << "/*outline*/ ";
f << "value<" << wire->width << "> " << mangle(wire) << ";\n";
}
void dump_reset_method(RTLIL::Module *module)
{
int mem_init_idx = 0;
inc_indent();
for (auto wire : module->wires()) {
const auto &wire_type = wire_types[wire];
if (!wire_type.is_named() || wire_type.is_local()) continue;
if (!wire_init.count(wire)) continue;
f << indent << mangle(wire) << " = ";
if (wire_types[wire].is_buffered()) {
f << "wire<" << wire->width << ">";
} else {
f << "value<" << wire->width << ">";
}
dump_const_init(wire_init.at(wire), wire->width);
f << ";\n";
if (edge_wires[wire] && !wire_types[wire].is_buffered()) {
f << indent << "prev_" << mangle(wire) << " = ";
dump_const(wire_init.at(wire), wire->width);
f << ";\n";
}
}
for (auto &mem : mod_memories[module]) {
for (auto &init : mem.inits) {
if (init.removed)
continue;
dump_attrs(&init);
int words = GetSize(init.data) / mem.width;
f << indent << "static const value<" << mem.width << "> ";
f << "mem_init_" << ++mem_init_idx << "[" << words << "] {";
inc_indent();
for (int n = 0; n < words; n++) {
if (n % 4 == 0)
f << "\n" << indent;
else
f << " ";
dump_const(init.data, mem.width, n * mem.width, /*fixed_width=*/true);
f << ",";
}
dec_indent();
f << "\n";
f << indent << "};\n";
f << indent << "std::copy(std::begin(mem_init_" << mem_init_idx << "), ";
f << "std::end(mem_init_" << mem_init_idx << "), ";
f << "&" << mangle(&mem) << ".data[" << stringf("%#x", init.addr.as_int()) << "]);\n";
}
}
for (auto cell : module->cells()) {
if (is_internal_cell(cell->type))
continue;
f << indent << mangle(cell);
RTLIL::Module *cell_module = module->design->module(cell->type);
if (cell_module->get_bool_attribute(ID(cxxrtl_blackbox))) {
f << "->reset();\n";
} else {
f << ".reset();\n";
}
}
dec_indent();
}
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=*/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_CASE:
dump_process_case(node.process);
break;
case FlowGraph::Node::Type::PROCESS_SYNC:
dump_process_syncs(node.process);
break;
case FlowGraph::Node::Type::MEM_RDPORT:
dump_mem_rdport(node.mem, node.portidx);
break;
case FlowGraph::Node::Type::MEM_WRPORTS:
dump_mem_wrports(node.mem);
break;
}
}
}
f << indent << "return converged;\n";
dec_indent();
}
void dump_debug_eval_method(RTLIL::Module *module)
{
inc_indent();
for (auto wire : module->wires())
dump_debug_wire(wire, /*is_local=*/true);
for (auto node : debug_schedule[module]) {
switch (node.type) {
case FlowGraph::Node::Type::CONNECT:
dump_connect(node.connect, /*for_debug=*/true);
break;
case FlowGraph::Node::Type::CELL_SYNC:
dump_cell_sync(node.cell, /*for_debug=*/true);
break;
case FlowGraph::Node::Type::CELL_EVAL:
dump_cell_eval(node.cell, /*for_debug=*/true);
break;
case FlowGraph::Node::Type::PROCESS_CASE:
dump_process_case(node.process, /*for_debug=*/true);
break;
case FlowGraph::Node::Type::PROCESS_SYNC:
dump_process_syncs(node.process, /*for_debug=*/true);
break;
case FlowGraph::Node::Type::MEM_RDPORT:
dump_mem_rdport(node.mem, node.portidx, /*for_debug=*/true);
break;
case FlowGraph::Node::Type::MEM_WRPORTS:
dump_mem_wrports(node.mem, /*for_debug=*/true);
break;
default:
log_abort();
}
}
dec_indent();
}
void dump_commit_method(RTLIL::Module *module)
{
inc_indent();
f << indent << "bool changed = false;\n";
for (auto wire : module->wires()) {
const auto &wire_type = wire_types[wire];
if (wire_type.type == WireType::MEMBER && edge_wires[wire])
f << indent << "prev_" << mangle(wire) << " = " << mangle(wire) << ";\n";
if (wire_type.is_buffered())
f << indent << "if (" << mangle(wire) << ".commit()) changed = true;\n";
}
if (!module->get_bool_attribute(ID(cxxrtl_blackbox))) {
for (auto &mem : mod_memories[module]) {
if (!writable_memories.count({module, mem.memid}))
continue;
f << indent << "if (" << mangle(&mem) << ".commit()) changed = true;\n";
}
for (auto cell : module->cells()) {
if (is_internal_cell(cell->type))
continue;
const char *access = is_cxxrtl_blackbox_cell(cell) ? "->" : ".";
f << indent << "if (" << mangle(cell) << access << "commit()) changed = true;\n";
}
}
f << indent << "return changed;\n";
dec_indent();
}
void dump_debug_info_method(RTLIL::Module *module)
{
size_t count_public_wires = 0;
size_t count_member_wires = 0;
size_t count_undriven = 0;
size_t count_driven_sync = 0;
size_t count_driven_comb = 0;
size_t count_mixed_driver = 0;
size_t count_alias_wires = 0;
size_t count_const_wires = 0;
size_t count_inline_wires = 0;
size_t count_skipped_wires = 0;
inc_indent();
f << indent << "assert(path.empty() || path[path.size() - 1] == ' ');\n";
for (auto wire : module->wires()) {
const auto &debug_wire_type = debug_wire_types[wire];
if (!wire->name.isPublic())
continue;
count_public_wires++;
switch (debug_wire_type.type) {
case WireType::BUFFERED:
case WireType::MEMBER: {
// Member wire
std::vector<std::string> flags;
if (wire->port_input && wire->port_output)
flags.push_back("INOUT");
else if (wire->port_output)
flags.push_back("OUTPUT");
else if (wire->port_input)
flags.push_back("INPUT");
bool has_driven_sync = false;
bool has_driven_comb = false;
bool has_undriven = false;
if (!module->get_bool_attribute(ID(cxxrtl_blackbox))) {
for (auto bit : SigSpec(wire))
if (!bit_has_state.count(bit))
has_undriven = true;
else if (bit_has_state[bit])
has_driven_sync = true;
else
has_driven_comb = true;
} else if (wire->port_output) {
switch (cxxrtl_port_type(module, wire->name)) {
case CxxrtlPortType::SYNC:
has_driven_sync = true;
break;
case CxxrtlPortType::COMB:
has_driven_comb = true;
break;
case CxxrtlPortType::UNKNOWN:
has_driven_sync = has_driven_comb = true;
break;
}
} else {
has_undriven = true;
}
if (has_undriven)
flags.push_back("UNDRIVEN");
if (!has_driven_sync && !has_driven_comb && has_undriven)
count_undriven++;
if (has_driven_sync)
flags.push_back("DRIVEN_SYNC");
if (has_driven_sync && !has_driven_comb && !has_undriven)
count_driven_sync++;
if (has_driven_comb)
flags.push_back("DRIVEN_COMB");
if (!has_driven_sync && has_driven_comb && !has_undriven)
count_driven_comb++;
if (has_driven_sync + has_driven_comb + has_undriven > 1)
count_mixed_driver++;
f << indent << "items.add(path + " << escape_cxx_string(get_hdl_name(wire));
f << ", debug_item(" << mangle(wire) << ", " << wire->start_offset;
bool first = true;
for (auto flag : flags) {
if (first) {
first = false;
f << ", ";
} else {
f << "|";
}
f << "debug_item::" << flag;
}
f << "));\n";
count_member_wires++;
break;
}
case WireType::ALIAS: {
// Alias of a member wire
const RTLIL::Wire *aliasee = debug_wire_type.sig_subst.as_wire();
f << indent << "items.add(path + " << escape_cxx_string(get_hdl_name(wire));
f << ", debug_item(";
// If the aliasee is an outline, then the alias must be an outline, too; otherwise downstream
// tooling has no way to find out about the outline.
if (debug_wire_types[aliasee].is_outline())
f << "debug_eval_outline";
else
f << "debug_alias()";
f << ", " << mangle(aliasee) << ", " << wire->start_offset << "));\n";
count_alias_wires++;
break;
}
case WireType::CONST: {
// Wire tied to a constant
f << indent << "static const value<" << wire->width << "> const_" << mangle(wire) << " = ";
dump_const(debug_wire_type.sig_subst.as_const());
f << ";\n";
f << indent << "items.add(path + " << escape_cxx_string(get_hdl_name(wire));
f << ", debug_item(const_" << mangle(wire) << ", " << wire->start_offset << "));\n";
count_const_wires++;
break;
}
case WireType::OUTLINE: {
// Localized or inlined, but rematerializable wire
f << indent << "items.add(path + " << escape_cxx_string(get_hdl_name(wire));
f << ", debug_item(debug_eval_outline, " << mangle(wire) << ", " << wire->start_offset << "));\n";
count_inline_wires++;
break;
}
default: {
// Localized or inlined wire with no debug information
count_skipped_wires++;
break;
}
}
}
if (!module->get_bool_attribute(ID(cxxrtl_blackbox))) {
for (auto &mem : mod_memories[module]) {
if (!mem.memid.isPublic())
continue;
f << indent << "items.add(path + " << escape_cxx_string(mem.packed ? get_hdl_name(mem.cell) : get_hdl_name(mem.mem));
f << ", debug_item(" << mangle(&mem) << ", ";
f << mem.start_offset << "));\n";
}
for (auto cell : module->cells()) {
if (is_internal_cell(cell->type))
continue;
const char *access = is_cxxrtl_blackbox_cell(cell) ? "->" : ".";
f << indent << mangle(cell) << access << "debug_info(items, ";
f << "path + " << escape_cxx_string(get_hdl_name(cell) + ' ') << ");\n";
}
}
dec_indent();
log_debug("Debug information statistics for module `%s':\n", log_id(module));
log_debug(" Public wires: %zu, of which:\n", count_public_wires);
log_debug(" Member wires: %zu, of which:\n", count_member_wires);
log_debug(" Undriven: %zu (incl. inputs)\n", count_undriven);
log_debug(" Driven sync: %zu\n", count_driven_sync);
log_debug(" Driven comb: %zu\n", count_driven_comb);
log_debug(" Mixed driver: %zu\n", count_mixed_driver);
if (!module->get_bool_attribute(ID(cxxrtl_blackbox))) {
log_debug(" Inline wires: %zu\n", count_inline_wires);
log_debug(" Alias wires: %zu\n", count_alias_wires);
log_debug(" Const wires: %zu\n", count_const_wires);
log_debug(" Other wires: %zu%s\n", count_skipped_wires,
count_skipped_wires > 0 ? " (debug unavailable)" : "");
}
}
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=*/false);
}
f << "\n";
f << indent << "void reset() override {\n";
dump_reset_method(module);
f << indent << "}\n";
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";
if (debug_info) {
f << indent << "void debug_info(debug_items &items, std::string path = \"\") override {\n";
dump_debug_info_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=*/false);
for (auto wire : module->wires())
dump_debug_wire(wire, /*is_local=*/false);
bool has_memories = false;
for (auto &mem : mod_memories[module]) {
dump_attrs(&mem);
f << indent << "memory<" << mem.width << "> " << mangle(&mem)
<< " { " << mem.size << "u };\n";
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(get_hdl_name(cell)) << ", ";
dump_metadata_map(cell->parameters);
f << ", ";
dump_metadata_map(cell->attributes);
f << ");\n";
} else {
f << indent << mangle(cell_module) << " " << mangle(cell) << " {interior()};\n";
}
has_cells = true;
}
if (has_cells)
f << "\n";
f << indent << mangle(module) << "(interior) {}\n";
f << indent << mangle(module) << "() {\n";
inc_indent();
f << indent << "reset();\n";
dec_indent();
f << indent << "};\n";
f << "\n";
f << indent << "void reset() override;\n";
f << indent << "bool eval() override;\n";
f << indent << "bool commit() override;\n";
if (debug_info) {
if (debug_eval) {
f << "\n";
f << indent << "void debug_eval();\n";
for (auto wire : module->wires())
if (debug_wire_types[wire].is_outline()) {
f << indent << "debug_outline debug_eval_outline { std::bind(&"
<< mangle(module) << "::debug_eval, this) };\n";
break;
}
}
f << "\n";
f << indent << "void debug_info(debug_items &items, std::string path = \"\") 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 << "void " << mangle(module) << "::reset() {\n";
dump_reset_method(module);
f << indent << "}\n";
f << "\n";
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";
if (debug_info) {
if (debug_eval) {
f << indent << "void " << mangle(module) << "::debug_eval() {\n";
dump_debug_eval_method(module);
f << indent << "}\n";
f << "\n";
}
f << indent << "CXXRTL_EXTREMELY_COLD\n";
f << indent << "void " << mangle(module) << "::debug_info(debug_items &items, std::string path) {\n";
dump_debug_info_method(module);
f << indent << "}\n";
f << "\n";
}
}
void dump_design(RTLIL::Design *design)
{
RTLIL::Module *top_module = nullptr;
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;
if (module->get_bool_attribute(ID::top))
top_module = module;
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);
}
}
bool no_loops = topo_design.sort();
log_assert(no_loops);
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";
if (top_module != nullptr && debug_info) {
f << "#include <backends/cxxrtl/cxxrtl_capi.h>\n";
f << "\n";
f << "#ifdef __cplusplus\n";
f << "extern \"C\" {\n";
f << "#endif\n";
f << "\n";
f << "cxxrtl_toplevel " << design_ns << "_create();\n";
f << "\n";
f << "#ifdef __cplusplus\n";
f << "}\n";
f << "#endif\n";
f << "\n";
} else {
f << "// The CXXRTL C API is not available because the design is built without debug information.\n";
f << "\n";
}
f << "#ifdef __cplusplus\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 // __cplusplus\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 << "#if defined(CXXRTL_INCLUDE_CAPI_IMPL) || \\\n";
f << " defined(CXXRTL_INCLUDE_VCD_CAPI_IMPL)\n";
f << "#include <backends/cxxrtl/cxxrtl_capi.cc>\n";
f << "#endif\n";
f << "\n";
f << "#if defined(CXXRTL_INCLUDE_VCD_CAPI_IMPL)\n";
f << "#include <backends/cxxrtl/cxxrtl_vcd_capi.cc>\n";
f << "#endif\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";
f << "\n";
if (top_module != nullptr && debug_info) {
f << "extern \"C\"\n";
f << "cxxrtl_toplevel " << design_ns << "_create() {\n";
inc_indent();
std::string top_type = design_ns + "::" + mangle(top_module);
f << indent << "return new _cxxrtl_toplevel { ";
f << "std::unique_ptr<" << top_type << ">(new " + top_type + ")";
f << " };\n";
dec_indent();
f << "}\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);
if (signal.is_fully_const())
return; // a clock, or more commonly a reset, can be tied to a constant driver
log_assert(is_valid_clock(signal));
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;
// Cannot use as_wire because signal might not be a full wire, instead extract the wire from the sigbit
edge_wires.insert(sigbit.wire);
}
void analyze_design(RTLIL::Design *design)
{
bool has_feedback_arcs = false;
bool has_buffered_comb_wires = false;
for (auto module : design->modules()) {
if (!design->selected_module(module))
continue;
SigMap &sigmap = sigmaps[module];
sigmap.set(module);
std::vector<Mem> &memories = mod_memories[module];
memories = Mem::get_all_memories(module);
for (auto &mem : memories) {
mem.narrow();
mem.coalesce_inits();
}
if (module->get_bool_attribute(ID(cxxrtl_blackbox))) {
for (auto port : module->ports) {
RTLIL::Wire *wire = module->wire(port);
if (wire->port_input && !wire->port_output) {
wire_types[wire] = debug_wire_types[wire] = {WireType::MEMBER};
} else if (wire->port_input || wire->port_output) {
wire_types[wire] = debug_wire_types[wire] = {WireType::BUFFERED};
}
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;
}
for (auto wire : module->wires())
if (wire->has_attribute(ID::init))
wire_init[wire] = wire->attributes.at(ID::init);
// Construct a flow graph where each node is a basic computational operation generally corresponding
// to a fragment of the RTLIL netlist.
FlowGraph flow;
for (auto conn : module->connections())
flow.add_node(conn);
for (auto cell : module->cells()) {
if (!cell->known())
log_cmd_error("Unknown cell `%s'.\n", log_id(cell->type));
if (cell->is_mem_cell())
continue;
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));
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($adffe), ID($aldff), ID($aldffe), ID($dffsr), ID($dffsre), ID($sdff), ID($sdffe), ID($sdffce))) {
if (is_valid_clock(cell->getPort(ID::CLK)))
register_edge_signal(sigmap, cell->getPort(ID::CLK),
cell->parameters[ID::CLK_POLARITY].as_bool() ? RTLIL::STp : RTLIL::STn);
}
}
for (auto &mem : memories) {
flow.add_node(&mem);
// Clocked memory cells are treated like posedge/negedge processes as well.
for (auto &port : mem.rd_ports) {
if (port.clk_enable)
if (is_valid_clock(port.clk))
register_edge_signal(sigmap, port.clk,
port.clk_polarity ? RTLIL::STp : RTLIL::STn);
// For read ports, also move initial value to wire_init (if any).
for (int i = 0; i < GetSize(port.data); i++) {
if (port.init_value[i] != State::Sx) {
SigBit bit = port.data[i];
if (bit.wire) {
auto &init = wire_init[bit.wire];
if (init == RTLIL::Const()) {
init = RTLIL::Const(State::Sx, GetSize(bit.wire));
}
init[bit.offset] = port.init_value[i];
}
}
}
}
for (auto &port : mem.wr_ports) {
if (port.clk_enable)
if (is_valid_clock(port.clk))
register_edge_signal(sigmap, port.clk,
port.clk_polarity ? RTLIL::STp : RTLIL::STn);
}
if (!mem.wr_ports.empty())
writable_memories.insert({module, mem.memid});
}
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 &memwr : sync->mem_write_actions) {
writable_memories.insert({module, memwr.memid});
}
}
}
// Construct a linear order of the flow graph that minimizes the amount of feedback arcs. A flow graph
// without feedback arcs can generally be evaluated in a single pass, i.e. it always requires only
// a single delta cycle.
Scheduler<FlowGraph::Node> scheduler;
dict<FlowGraph::Node*, Scheduler<FlowGraph::Node>::Vertex*, hash_ptr_ops> node_vertex_map;
for (auto node : flow.nodes)
node_vertex_map[node] = scheduler.add(node);
for (auto node_comb_def : flow.node_comb_defs) {
auto vertex = node_vertex_map[node_comb_def.first];
for (auto wire : node_comb_def.second)
for (auto succ_node : flow.wire_uses[wire]) {
auto succ_vertex = node_vertex_map[succ_node];
vertex->succs.insert(succ_vertex);
succ_vertex->preds.insert(vertex);
}
}
// Find out whether the order includes any feedback arcs.
std::vector<FlowGraph::Node*> node_order;
pool<FlowGraph::Node*, hash_ptr_ops> evaluated_nodes;
pool<const RTLIL::Wire*> feedback_wires;
for (auto vertex : scheduler.schedule()) {
auto node = vertex->data;
node_order.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 unbuffered.
evaluated_nodes.insert(node);
for (auto wire : flow.node_comb_defs[node])
for (auto succ_node : flow.wire_uses[wire])
if (evaluated_nodes[succ_node])
feedback_wires.insert(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));
}
// Conservatively assign wire types. Assignment of types BUFFERED and MEMBER is final, but assignment
// of type LOCAL may be further refined to UNUSED or INLINE.
for (auto wire : module->wires()) {
auto &wire_type = wire_types[wire];
wire_type = {WireType::BUFFERED};
if (feedback_wires[wire]) continue;
if (wire->port_output && !module->get_bool_attribute(ID::top)) continue;
if (!wire->name.isPublic() && !unbuffer_internal) continue;
if (wire->name.isPublic() && !unbuffer_public) continue;
if (flow.wire_sync_defs.count(wire) > 0) continue;
wire_type = {WireType::MEMBER};
if (edge_wires[wire]) continue;
if (wire->get_bool_attribute(ID::keep)) continue;
if (wire->port_input || wire->port_output) continue;
if (!wire->name.isPublic() && !localize_internal) continue;
if (wire->name.isPublic() && !localize_public) continue;
wire_type = {WireType::LOCAL};
}
// Discover nodes reachable from primary outputs (i.e. members) and collect reachable wire users.
pool<FlowGraph::Node*, hash_ptr_ops> worklist;
for (auto node : flow.nodes) {
if (node->type == FlowGraph::Node::Type::CELL_EVAL && is_effectful_cell(node->cell->type))
worklist.insert(node); // node has effects
else if (node->type == FlowGraph::Node::Type::MEM_WRPORTS)
worklist.insert(node); // node is memory write
else if (node->type == FlowGraph::Node::Type::PROCESS_SYNC && is_memwr_process(node->process))
worklist.insert(node); // node is memory write
else if (flow.node_sync_defs.count(node))
worklist.insert(node); // node is a flip-flop
else if (flow.node_comb_defs.count(node)) {
for (auto wire : flow.node_comb_defs[node])
if (wire_types[wire].is_member())
worklist.insert(node); // node drives public wires
}
}
dict<const RTLIL::Wire*, pool<FlowGraph::Node*, hash_ptr_ops>> live_wires;
pool<FlowGraph::Node*, hash_ptr_ops> live_nodes;
while (!worklist.empty()) {
auto node = worklist.pop();
live_nodes.insert(node);
for (auto wire : flow.node_uses[node]) {
live_wires[wire].insert(node);
for (auto pred_node : flow.wire_comb_defs[wire])
if (!live_nodes[pred_node])
worklist.insert(pred_node);
}
}
// Refine wire types taking into account the amount of uses from reachable nodes only.
for (auto wire : module->wires()) {
auto &wire_type = wire_types[wire];
if (!wire_type.is_local()) continue;
if (live_wires[wire].empty()) {
wire_type = {WireType::UNUSED}; // wire never used
continue;
}
if (!wire->name.isPublic() && !inline_internal) continue;
if (wire->name.isPublic() && !inline_public) continue;
if (flow.is_inlinable(wire, live_wires[wire])) {
if (flow.wire_comb_defs[wire].size() > 1)
log_cmd_error("Wire %s.%s has multiple drivers!\n", log_id(module), log_id(wire));
log_assert(flow.wire_comb_defs[wire].size() == 1);
FlowGraph::Node *node = *flow.wire_comb_defs[wire].begin();
switch (node->type) {
case FlowGraph::Node::Type::CELL_EVAL:
if (!is_inlinable_cell(node->cell->type)) continue;
wire_type = {WireType::INLINE, node->cell}; // wire replaced with cell
break;
case FlowGraph::Node::Type::CONNECT:
wire_type = {WireType::INLINE, node->connect.second}; // wire replaced with sig
break;
default: continue;
}
live_nodes.erase(node);
}
}
// Emit reachable nodes in eval().
for (auto node : node_order)
if (live_nodes[node])
schedule[module].push_back(*node);
// 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_comb_wires;
for (auto wire : module->wires())
if (wire_types[wire].is_buffered() && !feedback_wires[wire] && flow.wire_comb_defs[wire].size() > 0)
buffered_comb_wires.insert(wire);
if (!buffered_comb_wires.empty()) {
has_buffered_comb_wires = true;
log("Module `%s' contains buffered combinatorial wires:\n", log_id(module));
for (auto wire : buffered_comb_wires)
log(" %s\n", log_id(wire));
}
// Record whether eval() requires only one delta cycle in this module.
eval_converges[module] = feedback_wires.empty() && buffered_comb_wires.empty();
if (debug_info) {
// Annotate wire bits with the type of their driver; this is exposed in the debug metadata.
for (auto item : flow.bit_has_state)
bit_has_state.insert(item);
// Assign debug information wire types to public wires according to the chosen debug level.
// Unlike with optimized wire types, all assignments here are final.
for (auto wire : module->wires()) {
const auto &wire_type = wire_types[wire];
auto &debug_wire_type = debug_wire_types[wire];
if (!debug_info) continue;
if (wire->port_input || wire_type.is_buffered())
debug_wire_type = wire_type; // wire contains state
else if (!wire->name.isPublic())
continue; // internal and stateless
if (!debug_member) continue;
if (wire_type.is_member())
debug_wire_type = wire_type; // wire is a member
if (!debug_alias) continue;
const RTLIL::Wire *it = wire;
while (flow.is_inlinable(it)) {
log_assert(flow.wire_comb_defs[it].size() == 1);
FlowGraph::Node *node = *flow.wire_comb_defs[it].begin();
if (node->type != FlowGraph::Node::Type::CONNECT) break; // not an alias
RTLIL::SigSpec rhs = node->connect.second;
if (rhs.is_fully_const()) {
debug_wire_type = {WireType::CONST, rhs}; // wire replaced with const
} else if (rhs.is_wire()) {
if (wire_types[rhs.as_wire()].is_member())
debug_wire_type = {WireType::ALIAS, rhs}; // wire replaced with wire
else if (debug_eval && rhs.as_wire()->name.isPublic())
debug_wire_type = {WireType::ALIAS, rhs}; // wire replaced with outline
it = rhs.as_wire(); // and keep looking
continue;
}
break;
}
if (!debug_eval) continue;
if (!debug_wire_type.is_exact() && !wire_type.is_member())
debug_wire_type = {WireType::OUTLINE}; // wire is local or inlined
}
// Discover nodes reachable from primary outputs (i.e. outlines) up until primary inputs (i.e. members)
// and collect reachable wire users.
pool<FlowGraph::Node*, hash_ptr_ops> worklist;
for (auto node : flow.nodes) {
if (flow.node_comb_defs.count(node))
for (auto wire : flow.node_comb_defs[node])
if (debug_wire_types[wire].is_outline())
worklist.insert(node); // node drives outline
}
dict<const RTLIL::Wire*, pool<FlowGraph::Node*, hash_ptr_ops>> debug_live_wires;
pool<FlowGraph::Node*, hash_ptr_ops> debug_live_nodes;
while (!worklist.empty()) {
auto node = worklist.pop();
debug_live_nodes.insert(node);
for (auto wire : flow.node_uses[node]) {
if (debug_wire_types[wire].is_member())
continue; // node uses member
if (debug_wire_types[wire].is_exact())
continue; // node uses alias or const
debug_live_wires[wire].insert(node);
for (auto pred_node : flow.wire_comb_defs[wire])
if (!debug_live_nodes[pred_node])
worklist.insert(pred_node);
}
}
// Assign debug information wire types to internal wires used by reachable nodes. This is similar
// to refining optimized wire types with the exception that the assignments here are first and final.
for (auto wire : module->wires()) {
const auto &wire_type = wire_types[wire];
auto &debug_wire_type = debug_wire_types[wire];
if (wire->name.isPublic()) continue;
if (debug_live_wires[wire].empty()) {
continue; // wire never used
} else if (flow.is_inlinable(wire, debug_live_wires[wire])) {
log_assert(flow.wire_comb_defs[wire].size() == 1);
FlowGraph::Node *node = *flow.wire_comb_defs[wire].begin();
switch (node->type) {
case FlowGraph::Node::Type::CELL_EVAL:
if (!is_inlinable_cell(node->cell->type)) continue;
debug_wire_type = {WireType::INLINE, node->cell}; // wire replaced with cell
break;
case FlowGraph::Node::Type::CONNECT:
debug_wire_type = {WireType::INLINE, node->connect.second}; // wire replaced with sig
break;
default: continue;
}
debug_live_nodes.erase(node);
} else if (wire_type.is_member() || wire_type.type == WireType::LOCAL) {
debug_wire_type = wire_type; // wire not inlinable
} else {
log_assert(wire_type.type == WireType::INLINE ||
wire_type.type == WireType::UNUSED);
if (flow.wire_comb_defs[wire].size() == 0) {
if (wire_init.count(wire)) { // wire never modified
debug_wire_type = {WireType::CONST, wire_init.at(wire)};
} else {
debug_wire_type = {WireType::CONST, RTLIL::SigSpec(RTLIL::S0, wire->width)};
}
} else {
debug_wire_type = {WireType::LOCAL}; // wire used only for debug
}
}
}
// Emit reachable nodes in debug_eval().
for (auto node : node_order)
if (debug_live_nodes[node])
debug_schedule[module].push_back(*node);
}
auto show_wire_type = [&](const RTLIL::Wire* wire, const WireType &wire_type) {
const char *type_str;
switch (wire_type.type) {
case WireType::UNUSED: type_str = "UNUSED"; break;
case WireType::BUFFERED: type_str = "BUFFERED"; break;
case WireType::MEMBER: type_str = "MEMBER"; break;
case WireType::OUTLINE: type_str = "OUTLINE"; break;
case WireType::LOCAL: type_str = "LOCAL"; break;
case WireType::INLINE: type_str = "INLINE"; break;
case WireType::ALIAS: type_str = "ALIAS"; break;
case WireType::CONST: type_str = "CONST"; break;
default: type_str = "(invalid)";
}
if (wire_type.sig_subst.empty())
log_debug(" %s: %s\n", log_signal((RTLIL::Wire*)wire), type_str);
else
log_debug(" %s: %s = %s\n", log_signal((RTLIL::Wire*)wire), type_str, log_signal(wire_type.sig_subst));
};
if (print_wire_types && !wire_types.empty()) {
log_debug("Wire types:\n");
for (auto wire_type : wire_types)
show_wire_type(wire_type.first, wire_type.second);
}
if (print_debug_wire_types && !debug_wire_types.empty()) {
log_debug("Debug wire types:\n");
for (auto debug_wire_type : debug_wire_types)
show_wire_type(debug_wire_type.first, debug_wire_type.second);
}
}
if (has_feedback_arcs || has_buffered_comb_wires) {
// Although both non-feedback buffered combinatorial wires and apparent feedback wires may be eliminated
// by optimizing the design, if after `proc; flatten` 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_comb_wires)
why_pessimistic = "buffered combinatorial wires";
log_warning("Design contains %s, which require delta cycles during evaluation.\n", why_pessimistic);
if (!run_flatten)
log("Flattening may eliminate %s from the design.\n", why_pessimistic);
if (!run_proc)
log("Converting processes to netlists may eliminate %s from the design.\n", why_pessimistic);
}
}
void check_design(RTLIL::Design *design, bool &has_sync_init)
{
has_sync_init = 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;
}
}
void prepare_design(RTLIL::Design *design)
{
bool did_anything = false;
bool has_sync_init;
log_push();
check_design(design, has_sync_init);
if (run_hierarchy) {
Pass::call(design, "hierarchy -auto-top");
did_anything = true;
}
if (run_flatten) {
Pass::call(design, "flatten");
did_anything = true;
}
if (run_proc) {
Pass::call(design, "proc");
did_anything = true;
} 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");
did_anything = true;
}
// Recheck the design if it was modified.
if (did_anything)
check_design(design, has_sync_init);
log_assert(!has_sync_init);
log_pop();
if (did_anything)
log_spacer();
analyze_design(design);
}
};
struct CxxrtlBackend : public Backend {
static const int DEFAULT_OPT_LEVEL = 6;
static const int DEFAULT_DEBUG_LEVEL = 4;
CxxrtlBackend() : Backend("cxxrtl", "convert design to C++ RTL simulation") { }
void help() 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.set(false);\n");
log(" top.step();\n");
log(" top.p_clk.set(true);\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(" -print-wire-types, -print-debug-wire-types\n");
log(" enable additional debug logging, for pass developers.\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(" -nohierarchy\n");
log(" use design hierarchy as-is. in most designs, a top module should be\n");
log(" present as it is exposed through the C API and has unbuffered outputs\n");
log(" for improved performance; it will be determined automatically if absent.\n");
log("\n");
log(" -noflatten\n");
log(" don't flatten the design. fully flattened designs can evaluate within\n");
log(" one delta cycle if they have no combinatorial feedback.\n");
log(" note that the debug interface and waveform dumps use full hierarchical\n");
log(" names for all wires even in flattened designs.\n");
log("\n");
log(" -noproc\n");
log(" don't convert processes to netlists. in most designs, converting\n");
log(" processes significantly improves evaluation performance at the cost of\n");
log(" slight increase in compilation time.\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(" unbuffer 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 inline internal wires if possible.\n");
log("\n");
log(" -O4\n");
log(" like -O3, and unbuffer public wires not marked (*keep*) if possible.\n");
log("\n");
log(" -O5\n");
log(" like -O4, and localize public wires not marked (*keep*) if possible.\n");
log("\n");
log(" -O6\n");
log(" like -O5, and inline public wires not marked (*keep*) if possible.\n");
log("\n");
log(" -g <level>\n");
log(" set the debug level. the default is -g%d. higher debug levels provide\n", DEFAULT_DEBUG_LEVEL);
log(" more visibility and generate more code, but do not pessimize evaluation.\n");
log("\n");
log(" -g0\n");
log(" no debug information. the C API is disabled.\n");
log("\n");
log(" -g1\n");
log(" include bare minimum of debug information necessary to access all design\n");
log(" state. the C API is enabled.\n");
log("\n");
log(" -g2\n");
log(" like -g1, but include debug information for all public wires that are\n");
log(" directly accessible through the C++ interface.\n");
log("\n");
log(" -g3\n");
log(" like -g2, and include debug information for public wires that are tied\n");
log(" to a constant or another public wire.\n");
log("\n");
log(" -g4\n");
log(" like -g3, and compute debug information on demand for all public wires\n");
log(" that were optimized out.\n");
log("\n");
}
void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) override
{
bool print_wire_types = false;
bool print_debug_wire_types = false;
bool nohierarchy = false;
bool noflatten = false;
bool noproc = false;
int opt_level = DEFAULT_OPT_LEVEL;
int debug_level = DEFAULT_DEBUG_LEVEL;
CxxrtlWorker worker;
log_header(design, "Executing CXXRTL backend.\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++)
{
if (args[argidx] == "-print-wire-types") {
print_wire_types = true;
continue;
}
if (args[argidx] == "-print-debug-wire-types") {
print_debug_wire_types = true;
continue;
}
if (args[argidx] == "-nohierarchy") {
nohierarchy = true;
continue;
}
if (args[argidx] == "-noflatten") {
noflatten = true;
continue;
}
if (args[argidx] == "-noproc") {
noproc = true;
continue;
}
if (args[argidx] == "-Og") {
log_warning("The `-Og` option has been removed. Use `-g3` instead for complete "
"design coverage regardless of optimization level.\n");
continue;
}
if (args[argidx] == "-O" && argidx+1 < args.size() && args[argidx+1] == "g") {
argidx++;
log_warning("The `-Og` option has been removed. Use `-g3` instead for complete "
"design coverage regardless of optimization level.\n");
continue;
}
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] == "-g" && argidx+1 < args.size()) {
debug_level = std::stoi(args[++argidx]);
continue;
}
if (args[argidx].substr(0, 2) == "-g" && args[argidx].size() == 3 && isdigit(args[argidx][2])) {
debug_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);
worker.print_wire_types = print_wire_types;
worker.print_debug_wire_types = print_debug_wire_types;
worker.run_hierarchy = !nohierarchy;
worker.run_flatten = !noflatten;
worker.run_proc = !noproc;
switch (opt_level) {
// the highest level here must match DEFAULT_OPT_LEVEL
case 6:
worker.inline_public = true;
YS_FALLTHROUGH
case 5:
worker.localize_public = true;
YS_FALLTHROUGH
case 4:
worker.unbuffer_public = true;
YS_FALLTHROUGH
case 3:
worker.inline_internal = true;
YS_FALLTHROUGH
case 2:
worker.localize_internal = true;
YS_FALLTHROUGH
case 1:
worker.unbuffer_internal = true;
YS_FALLTHROUGH
case 0:
break;
default:
log_cmd_error("Invalid optimization level %d.\n", opt_level);
}
switch (debug_level) {
// the highest level here must match DEFAULT_DEBUG_LEVEL
case 4:
worker.debug_eval = true;
YS_FALLTHROUGH
case 3:
worker.debug_alias = true;
YS_FALLTHROUGH
case 2:
worker.debug_member = true;
YS_FALLTHROUGH
case 1:
worker.debug_info = true;
YS_FALLTHROUGH
case 0:
break;
default:
log_cmd_error("Invalid debug information level %d.\n", debug_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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