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-rw-r--r--backends/firrtl/firrtl.cc352
1 files changed, 294 insertions, 58 deletions
diff --git a/backends/firrtl/firrtl.cc b/backends/firrtl/firrtl.cc
index 9739a7a9f..44c3397da 100644
--- a/backends/firrtl/firrtl.cc
+++ b/backends/firrtl/firrtl.cc
@@ -102,6 +102,260 @@ const char *make_id(IdString id)
return namecache.at(id).c_str();
}
+std::string dump_const_string(const RTLIL::Const &data)
+{
+ std::string res_str;
+
+ std::string str = data.decode_string();
+ for (size_t i = 0; i < str.size(); i++)
+ {
+ if (str[i] == '\n')
+ res_str += "\\n";
+ else if (str[i] == '\t')
+ res_str += "\\t";
+ else if (str[i] < 32)
+ res_str += stringf("\\%03o", str[i]);
+ else if (str[i] == '"')
+ res_str += "\\\"";
+ else if (str[i] == '\\')
+ res_str += "\\\\";
+ else
+ res_str += str[i];
+ }
+
+ return res_str;
+}
+
+std::string dump_const(const RTLIL::Const &data)
+{
+ std::string res_str;
+
+ // // For debugging purposes to find out how Yosys encodes flags.
+ // res_str += stringf("flags_%x --> ", data.flags);
+
+ // Real-valued parameter.
+ if (data.flags & RTLIL::CONST_FLAG_REAL)
+ {
+ // Yosys stores real values as strings, so we call the string dumping code.
+ res_str += dump_const_string(data);
+ }
+ // String parameter.
+ else if (data.flags & RTLIL::CONST_FLAG_STRING)
+ {
+ res_str += "\"";
+ res_str += dump_const_string(data);
+ res_str += "\"";
+ }
+ // Numeric (non-real) parameter.
+ else
+ {
+ int width = data.bits.size();
+
+ // If a standard 32-bit int, then emit standard int value like "56" or
+ // "-56". Firrtl supports negative-valued int literals.
+ //
+ // SignedInt
+ // : ( '+' | '-' ) PosInt
+ // ;
+ if (width <= 32)
+ {
+ int32_t int_val = 0;
+
+ for (int i = 0; i < width; i++)
+ {
+ switch (data.bits[i])
+ {
+ case State::S0: break;
+ case State::S1: int_val |= (1 << i); break;
+ default:
+ log_error("Unexpected int value\n");
+ break;
+ }
+ }
+
+ res_str += stringf("%d", int_val);
+ }
+ else
+ {
+ // If value is larger than 32 bits, then emit a binary representation of
+ // the number as integers are not large enough to contain the result.
+ // There is a caveat to this approach though:
+ //
+ // Note that parameter may be defined as having a fixed width as follows:
+ //
+ // parameter signed [26:0] test_signed;
+ // parameter [26:0] test_unsigned;
+ // parameter signed [40:0] test_signed_large;
+ //
+ // However, if you assign a value on the RHS without specifying the
+ // precision, then yosys considers the value you used as an int and
+ // assigns it a width of 32 bits regardless of the type of the parameter.
+ //
+ // defparam <inst_name> .test_signed = 49; (width = 32, though should be 27 based on definition)
+ // defparam <inst_name> .test_unsigned = 40'd35; (width = 40, though should be 27 based on definition)
+ // defparam <inst_name> .test_signed_large = 40'd12; (width = 40)
+ //
+ // We therefore may lose the precision of the original verilog literal if
+ // it was written without its bitwidth specifier.
+
+ // Emit binary prefix for string.
+ res_str += "\"b";
+
+ // Emit bits.
+ for (int i = width - 1; i >= 0; i--)
+ {
+ log_assert(i < width);
+ switch (data.bits[i])
+ {
+ case State::S0: res_str += "0"; break;
+ case State::S1: res_str += "1"; break;
+ case State::Sx: res_str += "x"; break;
+ case State::Sz: res_str += "z"; break;
+ case State::Sa: res_str += "-"; break;
+ case State::Sm: res_str += "m"; break;
+ }
+ }
+
+ res_str += "\"";
+ }
+ }
+
+ return res_str;
+}
+
+std::string extmodule_name(RTLIL::Cell *cell, RTLIL::Module *mod_instance)
+{
+ // Since we are creating a custom extmodule for every cell that instantiates
+ // this blackbox, we need to create a custom name for it. We just use the
+ // name of the blackbox itself followed by the name of the cell.
+ const std::string cell_name = std::string(make_id(cell->name));
+ const std::string blackbox_name = std::string(make_id(mod_instance->name));
+ const std::string extmodule_name = blackbox_name + "_" + cell_name;
+ return extmodule_name;
+}
+
+/**
+ * Emits a parameterized extmodule. Instance parameters are obtained from
+ * ''cell'' as it represents the instantiation of the blackbox defined by
+ * ''mod_instance'' and therefore contains all its instance parameters.
+ */
+void emit_extmodule(RTLIL::Cell *cell, RTLIL::Module *mod_instance, std::ostream &f)
+{
+ const std::string indent = " ";
+
+ const std::string blackbox_name = std::string(make_id(mod_instance->name));
+ const std::string exported_name = extmodule_name(cell, mod_instance);
+
+ // We use the cell's fileinfo for this extmodule as its parameters come from
+ // the cell and not from the module itself (the module contains default
+ // parameters, not the instance-specific ones we're using to emit the
+ // extmodule).
+ const std::string extmoduleFileinfo = getFileinfo(cell);
+
+ // Emit extmodule header.
+ f << stringf(" extmodule %s: %s\n", exported_name.c_str(), extmoduleFileinfo.c_str());
+
+ // Emit extmodule ports.
+ for (auto wire : mod_instance->wires())
+ {
+ const auto wireName = make_id(wire->name);
+ const std::string wireFileinfo = getFileinfo(wire);
+
+ if (wire->port_input && wire->port_output)
+ {
+ log_error("Module port %s.%s is inout!\n", log_id(mod_instance), log_id(wire));
+ }
+
+ const std::string portDecl = stringf("%s%s %s: UInt<%d> %s\n",
+ indent.c_str(),
+ wire->port_input ? "input" : "output",
+ wireName,
+ wire->width,
+ wireFileinfo.c_str()
+ );
+
+ f << portDecl;
+ }
+
+ // Emit extmodule "defname" field. This is the name of the verilog blackbox
+ // that is used when verilog is emitted, so we use the name of mod_instance
+ // here.
+ f << stringf("%sdefname = %s\n", indent.c_str(), blackbox_name.c_str());
+
+ // Emit extmodule generic parameters.
+ for (const auto &p : cell->parameters)
+ {
+ const RTLIL::IdString p_id = p.first;
+ const RTLIL::Const p_value = p.second;
+
+ std::string param_name(p_id.c_str());
+ const std::string param_value = dump_const(p_value);
+
+ // Remove backslashes from parameters as these come from the internal RTLIL
+ // naming scheme, but should not exist in the emitted firrtl blackboxes.
+ // When firrtl is converted to verilog and given to downstream synthesis
+ // tools, these tools expect to find blackbox names and parameters as they
+ // were originally defined, i.e. without the extra RTLIL naming conventions.
+ param_name.erase(
+ std::remove(param_name.begin(), param_name.end(), '\\'),
+ param_name.end()
+ );
+
+ f << stringf("%sparameter %s = %s\n", indent.c_str(), param_name.c_str(), param_value.c_str());
+ }
+
+ f << "\n";
+}
+
+/**
+ * Emits extmodules for every instantiated blackbox in the design.
+ *
+ * RTLIL stores instance parameters at the cell's instantiation location.
+ * However, firrtl does not support module parameterization (everything is
+ * already elaborated). Firrtl instead supports external modules (extmodule),
+ * i.e. blackboxes that are defined by verilog and which have no body in
+ * firrtl itself other than the declaration of the blackboxes ports and
+ * parameters.
+ *
+ * Furthermore, firrtl does not support parameterization (even of extmodules)
+ * at a module's instantiation location and users must instead declare
+ * different extmodules with different instance parameters in the extmodule
+ * definition itself.
+ *
+ * This function goes through the design to identify all RTLIL blackboxes
+ * and emit parameterized extmodules with a unique name for each of them. The
+ * name that's given to the extmodule is
+ *
+ * <blackbox_name>_<instance_name>
+ *
+ * Beware that it is therefore necessary for users to replace "parameterized"
+ * instances in the RTLIL sense with these custom extmodules for the firrtl to
+ * be valid.
+ */
+void emit_elaborated_extmodules(RTLIL::Design *design, std::ostream &f)
+{
+ for (auto module : design->modules())
+ {
+ for (auto cell : module->cells())
+ {
+ // Is this cell a module instance?
+ bool cellIsModuleInstance = cell->type[0] != '$';
+
+ if (cellIsModuleInstance)
+ {
+ // Find the module corresponding to this instance.
+ auto modInstance = design->module(cell->type);
+ bool modIsBlackbox = modInstance->get_blackbox_attribute();
+
+ if (modIsBlackbox)
+ {
+ emit_extmodule(cell, modInstance, f);
+ }
+ }
+ }
+ }
+}
+
struct FirrtlWorker
{
Module *module;
@@ -328,8 +582,16 @@ struct FirrtlWorker
log_warning("No instance for %s.%s\n", cell_type.c_str(), cell_name.c_str());
return;
}
+
+ // If the instance is that of a blackbox, use the modified extmodule name
+ // that contains per-instance parameterizations. These instances were
+ // emitted earlier in the firrtl backend.
+ const std::string instanceName = instModule->get_blackbox_attribute() ?
+ extmodule_name(cell, instModule) :
+ instanceOf;
+
std::string cellFileinfo = getFileinfo(cell);
- wire_exprs.push_back(stringf("%s" "inst %s%s of %s %s", indent.c_str(), cell_name.c_str(), cell_name_comment.c_str(), instanceOf.c_str(), cellFileinfo.c_str()));
+ wire_exprs.push_back(stringf("%s" "inst %s%s of %s %s", indent.c_str(), cell_name.c_str(), cell_name_comment.c_str(), instanceName.c_str(), cellFileinfo.c_str()));
for (auto it = cell->connections().begin(); it != cell->connections().end(); ++it) {
if (it->second.size() > 0) {
@@ -392,33 +654,6 @@ struct FirrtlWorker
return result;
}
- void emit_extmodule()
- {
- std::string moduleFileinfo = getFileinfo(module);
- f << stringf(" extmodule %s: %s\n", make_id(module->name), moduleFileinfo.c_str());
- vector<std::string> port_decls;
-
- for (auto wire : module->wires())
- {
- const auto wireName = make_id(wire->name);
- std::string wireFileinfo = getFileinfo(wire);
-
- if (wire->port_input && wire->port_output)
- {
- log_error("Module port %s.%s is inout!\n", log_id(module), log_id(wire));
- }
- port_decls.push_back(stringf(" %s %s: UInt<%d> %s\n", wire->port_input ? "input" : "output",
- wireName, wire->width, wireFileinfo.c_str()));
- }
-
- for (auto &str : port_decls)
- {
- f << str;
- }
-
- f << stringf("\n");
- }
-
void emit_module()
{
std::string moduleFileinfo = getFileinfo(module);
@@ -440,12 +675,12 @@ struct FirrtlWorker
{
if (wire->port_input && wire->port_output)
log_error("Module port %s.%s is inout!\n", log_id(module), log_id(wire));
- port_decls.push_back(stringf(" %s %s: UInt<%d> %s\n", wire->port_input ? "input" : "output",
+ port_decls.push_back(stringf("%s%s %s: UInt<%d> %s\n", indent.c_str(), wire->port_input ? "input" : "output",
wireName, wire->width, wireFileinfo.c_str()));
}
else
{
- wire_decls.push_back(stringf(" wire %s: UInt<%d> %s\n", wireName, wire->width, wireFileinfo.c_str()));
+ wire_decls.push_back(stringf("%swire %s: UInt<%d> %s\n", indent.c_str(), wireName, wire->width, wireFileinfo.c_str()));
}
}
@@ -476,7 +711,7 @@ struct FirrtlWorker
if (cell->type.in(ID($not), ID($logic_not), ID($_NOT_), ID($neg), ID($reduce_and), ID($reduce_or), ID($reduce_xor), ID($reduce_bool), ID($reduce_xnor)))
{
string a_expr = make_expr(cell->getPort(ID::A));
- wire_decls.push_back(stringf(" wire %s: UInt<%d> %s\n", y_id.c_str(), y_width, cellFileinfo.c_str()));
+ wire_decls.push_back(stringf("%swire %s: UInt<%d> %s\n", indent.c_str(), y_id.c_str(), y_width, cellFileinfo.c_str()));
if (a_signed) {
a_expr = "asSInt(" + a_expr + ")";
@@ -516,7 +751,7 @@ struct FirrtlWorker
if ((firrtl_is_signed && !always_uint))
expr = stringf("asUInt(%s)", expr.c_str());
- cell_exprs.push_back(stringf(" %s <= %s %s\n", y_id.c_str(), expr.c_str(), cellFileinfo.c_str()));
+ cell_exprs.push_back(stringf("%s%s <= %s %s\n", indent.c_str(), y_id.c_str(), expr.c_str(), cellFileinfo.c_str()));
register_reverse_wire_map(y_id, cell->getPort(ID::Y));
continue;
@@ -528,7 +763,7 @@ struct FirrtlWorker
string a_expr = make_expr(cell->getPort(ID::A));
string b_expr = make_expr(cell->getPort(ID::B));
std::string cellFileinfo = getFileinfo(cell);
- wire_decls.push_back(stringf(" wire %s: UInt<%d> %s\n", y_id.c_str(), y_width, cellFileinfo.c_str()));
+ wire_decls.push_back(stringf("%swire %s: UInt<%d> %s\n", indent.c_str(), y_id.c_str(), y_width, cellFileinfo.c_str()));
if (a_signed) {
a_expr = "asSInt(" + a_expr + ")";
@@ -746,7 +981,7 @@ struct FirrtlWorker
if ((firrtl_is_signed && !always_uint))
expr = stringf("asUInt(%s)", expr.c_str());
- cell_exprs.push_back(stringf(" %s <= %s %s\n", y_id.c_str(), expr.c_str(), cellFileinfo.c_str()));
+ cell_exprs.push_back(stringf("%s%s <= %s %s\n", indent.c_str(), y_id.c_str(), expr.c_str(), cellFileinfo.c_str()));
register_reverse_wire_map(y_id, cell->getPort(ID::Y));
continue;
@@ -759,11 +994,11 @@ struct FirrtlWorker
string a_expr = make_expr(cell->getPort(ID::A));
string b_expr = make_expr(cell->getPort(ID::B));
string s_expr = make_expr(cell->getPort(ID::S));
- wire_decls.push_back(stringf(" wire %s: UInt<%d> %s\n", y_id.c_str(), width, cellFileinfo.c_str()));
+ wire_decls.push_back(stringf("%swire %s: UInt<%d> %s\n", indent.c_str(), y_id.c_str(), width, cellFileinfo.c_str()));
string expr = stringf("mux(%s, %s, %s)", s_expr.c_str(), b_expr.c_str(), a_expr.c_str());
- cell_exprs.push_back(stringf(" %s <= %s %s\n", y_id.c_str(), expr.c_str(), cellFileinfo.c_str()));
+ cell_exprs.push_back(stringf("%s%s <= %s %s\n", indent.c_str(), y_id.c_str(), expr.c_str(), cellFileinfo.c_str()));
register_reverse_wire_map(y_id, cell->getPort(ID::Y));
continue;
@@ -902,9 +1137,9 @@ struct FirrtlWorker
string expr = make_expr(cell->getPort(ID::D));
string clk_expr = "asClock(" + make_expr(cell->getPort(ID::CLK)) + ")";
- wire_decls.push_back(stringf(" reg %s: UInt<%d>, %s %s\n", y_id.c_str(), width, clk_expr.c_str(), cellFileinfo.c_str()));
+ wire_decls.push_back(stringf("%sreg %s: UInt<%d>, %s %s\n", indent.c_str(), y_id.c_str(), width, clk_expr.c_str(), cellFileinfo.c_str()));
- cell_exprs.push_back(stringf(" %s <= %s %s\n", y_id.c_str(), expr.c_str(), cellFileinfo.c_str()));
+ cell_exprs.push_back(stringf("%s%s <= %s %s\n", indent.c_str(), y_id.c_str(), expr.c_str(), cellFileinfo.c_str()));
register_reverse_wire_map(y_id, cell->getPort(ID::Q));
continue;
@@ -923,7 +1158,7 @@ struct FirrtlWorker
string a_expr = make_expr(cell->getPort(ID::A));
// Get the initial bit selector
string b_expr = make_expr(cell->getPort(ID::B));
- wire_decls.push_back(stringf(" wire %s: UInt<%d>\n", y_id.c_str(), y_width));
+ wire_decls.push_back(stringf("%swire %s: UInt<%d>\n", indent.c_str(), y_id.c_str(), y_width));
if (cell->getParam(ID::B_SIGNED).as_bool()) {
// Use validif to constrain the selection (test the sign bit)
@@ -933,7 +1168,7 @@ struct FirrtlWorker
}
string expr = stringf("dshr(%s, %s)", a_expr.c_str(), b_expr.c_str());
- cell_exprs.push_back(stringf(" %s <= %s\n", y_id.c_str(), expr.c_str()));
+ cell_exprs.push_back(stringf("%s%s <= %s\n", indent.c_str(), y_id.c_str(), expr.c_str()));
register_reverse_wire_map(y_id, cell->getPort(ID::Y));
continue;
}
@@ -945,7 +1180,7 @@ struct FirrtlWorker
string b_expr = make_expr(cell->getPort(ID::B));
auto b_string = b_expr.c_str();
string expr;
- wire_decls.push_back(stringf(" wire %s: UInt<%d>\n", y_id.c_str(), y_width));
+ wire_decls.push_back(stringf("%swire %s: UInt<%d>\n", indent.c_str(), y_id.c_str(), y_width));
if (cell->getParam(ID::B_SIGNED).as_bool()) {
// We generate a left or right shift based on the sign of b.
@@ -959,7 +1194,7 @@ struct FirrtlWorker
} else {
expr = stringf("dshr(%s, %s)", a_expr.c_str(), b_string);
}
- cell_exprs.push_back(stringf(" %s <= %s\n", y_id.c_str(), expr.c_str()));
+ cell_exprs.push_back(stringf("%s%s <= %s\n", indent.c_str(), y_id.c_str(), expr.c_str()));
register_reverse_wire_map(y_id, cell->getPort(ID::Y));
continue;
}
@@ -972,8 +1207,8 @@ struct FirrtlWorker
if (a_width < y_width) {
a_expr = stringf("pad(%s, %d)", a_expr.c_str(), y_width);
}
- wire_decls.push_back(stringf(" wire %s: UInt<%d>\n", y_id.c_str(), y_width));
- cell_exprs.push_back(stringf(" %s <= %s\n", y_id.c_str(), a_expr.c_str()));
+ wire_decls.push_back(stringf("%swire %s: UInt<%d>\n", indent.c_str(), y_id.c_str(), y_width));
+ cell_exprs.push_back(stringf("%s%s <= %s\n", indent.c_str(), y_id.c_str(), a_expr.c_str()));
register_reverse_wire_map(y_id, cell->getPort(ID::Y));
continue;
}
@@ -986,8 +1221,8 @@ struct FirrtlWorker
int y_width = GetSize(conn.first);
string expr = make_expr(conn.second);
- wire_decls.push_back(stringf(" wire %s: UInt<%d>\n", y_id.c_str(), y_width));
- cell_exprs.push_back(stringf(" %s <= %s\n", y_id.c_str(), expr.c_str()));
+ wire_decls.push_back(stringf("%swire %s: UInt<%d>\n", indent.c_str(), y_id.c_str(), y_width));
+ cell_exprs.push_back(stringf("%s%s <= %s\n", indent.c_str(), y_id.c_str(), expr.c_str()));
register_reverse_wire_map(y_id, conn.first);
}
@@ -1053,13 +1288,13 @@ struct FirrtlWorker
if (is_valid) {
if (make_unconn_id) {
- wire_decls.push_back(stringf(" wire %s: UInt<1> %s\n", unconn_id.c_str(), wireFileinfo.c_str()));
+ wire_decls.push_back(stringf("%swire %s: UInt<1> %s\n", indent.c_str(), unconn_id.c_str(), wireFileinfo.c_str()));
// `invalid` is a firrtl construction for simulation so we will not
// tag it with a @[fileinfo] tag as it doesn't directly correspond to
// a specific line of verilog code.
- wire_decls.push_back(stringf(" %s is invalid\n", unconn_id.c_str()));
+ wire_decls.push_back(stringf("%s%s is invalid\n", indent.c_str(), unconn_id.c_str()));
}
- wire_exprs.push_back(stringf(" %s <= %s %s\n", make_id(wire->name), expr.c_str(), wireFileinfo.c_str()));
+ wire_exprs.push_back(stringf("%s%s <= %s %s\n", indent.c_str(), make_id(wire->name), expr.c_str(), wireFileinfo.c_str()));
} else {
if (make_unconn_id) {
unconn_id.clear();
@@ -1067,7 +1302,7 @@ struct FirrtlWorker
// `invalid` is a firrtl construction for simulation so we will not
// tag it with a @[fileinfo] tag as it doesn't directly correspond to
// a specific line of verilog code.
- wire_decls.push_back(stringf(" %s is invalid\n", make_id(wire->name)));
+ wire_decls.push_back(stringf("%s%s is invalid\n", indent.c_str(), make_id(wire->name)));
}
}
@@ -1112,12 +1347,7 @@ struct FirrtlWorker
void run()
{
- // Blackboxes should be emitted as `extmodule`s in firrtl. Only ports are
- // emitted in such a case.
- if (module->get_blackbox_attribute())
- emit_extmodule();
- else
- emit_module();
+ emit_module();
}
};
@@ -1180,10 +1410,16 @@ struct FirrtlBackend : public Backend {
std::string circuitFileinfo = getFileinfo(top);
*f << stringf("circuit %s: %s\n", make_id(top->name), circuitFileinfo.c_str());
+ emit_elaborated_extmodules(design, *f);
+
+ // Emit non-blackbox modules.
for (auto module : design->modules())
{
- FirrtlWorker worker(module, *f, design);
- worker.run();
+ if (!module->get_blackbox_attribute())
+ {
+ FirrtlWorker worker(module, *f, design);
+ worker.run();
+ }
}
namecache.clear();
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-31 18:28:42 +0000