From f6e16e7f4c65440783047d3f2b03563f36f6dae8 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Wed, 27 May 2020 00:21:15 +0000
Subject: [PATCH] cxxrtl: generate debug information for non-localized public
wires.
Debug information describes values, wires, and memories with a simple
C-compatible layout. It can be emitted on demand into a map, which
has no runtime cost when it is unused, and allows late bound designs.
The `hdlname` attribute is used as the lookup key such that original
names, as emitted by the frontend, can be used for debugging and
introspection.
---
backends/cxxrtl/cxxrtl.cc | 87 ++++++++++++++++++++++++++++++++++++++-
backends/cxxrtl/cxxrtl.h | 46 ++++++++++++++++++++-
2 files changed, 131 insertions(+), 2 deletions(-)
diff --git a/backends/cxxrtl/cxxrtl.cc b/backends/cxxrtl/cxxrtl.cc
index 0cceecbba..edd606c1a 100644
--- a/backends/cxxrtl/cxxrtl.cc
+++ b/backends/cxxrtl/cxxrtl.cc
@@ -502,6 +502,15 @@ std::string escape_cxx_string(const std::string &input)
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();
+}
+
struct CxxrtlWorker {
bool split_intf = false;
std::string intf_filename;
@@ -516,6 +525,8 @@ struct CxxrtlWorker {
bool run_proc_flatten = false;
bool max_opt_level = false;
+ bool debug_info = false;
+
std::ostringstream f;
std::string indent;
int temporary = 0;
@@ -1593,6 +1604,34 @@ struct CxxrtlWorker {
dec_indent();
}
+ void dump_debug_info_method(RTLIL::Module *module)
+ {
+ inc_indent();
+ f << indent << "assert(path.empty() || path[path.size() - 1] == ' ');\n";
+ for (auto wire : module->wires()) {
+ if (wire->name[0] != '\\')
+ continue;
+ if (localized_wires.count(wire))
+ continue;
+ f << indent << "items.emplace(path + " << escape_cxx_string(get_hdl_name(wire));
+ f << ", debug_item(" << mangle(wire) << "));\n";
+ }
+ for (auto &memory_it : module->memories) {
+ if (memory_it.first[0] != '\\')
+ continue;
+ f << indent << "items.emplace(path + " << escape_cxx_string(get_hdl_name(memory_it.second));
+ f << ", debug_item(" << mangle(memory_it.second) << "));\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();
+ }
+
void dump_metadata_map(const dict<RTLIL::IdString, RTLIL::Const> &metadata_map)
{
if (metadata_map.empty()) {
@@ -1641,6 +1680,12 @@ struct CxxrtlWorker {
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";
@@ -1689,7 +1734,7 @@ struct CxxrtlWorker {
if (cell_module->get_bool_attribute(ID(cxxrtl_blackbox))) {
f << indent << "std::unique_ptr<" << mangle(cell_module) << template_args(cell) << "> ";
f << mangle(cell) << " = " << mangle(cell_module) << template_args(cell);
- f << "::create(" << escape_cxx_string(cell->name.str()) << ", ";
+ f << "::create(" << escape_cxx_string(get_hdl_name(cell)) << ", ";
dump_metadata_map(cell->parameters);
f << ", ";
dump_metadata_map(cell->attributes);
@@ -1703,6 +1748,8 @@ struct CxxrtlWorker {
f << "\n";
f << indent << "bool eval() override;\n";
f << indent << "bool commit() override;\n";
+ if (debug_info)
+ f << indent << "void debug_info(debug_items &items, std::string path = \"\") override;\n";
dec_indent();
f << indent << "}; // struct " << mangle(module) << "\n";
f << "\n";
@@ -1721,6 +1768,12 @@ struct CxxrtlWorker {
dump_commit_method(module);
f << indent << "}\n";
f << "\n";
+ if (debug_info) {
+ 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)
@@ -2120,6 +2173,7 @@ struct CxxrtlWorker {
struct CxxrtlBackend : public Backend {
static const int DEFAULT_OPT_LEVEL = 5;
+ static const int DEFAULT_DEBUG_LEVEL = 1;
CxxrtlBackend() : Backend("cxxrtl", "convert design to C++ RTL simulation") { }
void help() YS_OVERRIDE
@@ -2313,10 +2367,22 @@ struct CxxrtlBackend : public Backend {
log(" -O5\n");
log(" like -O4, and run `proc; flatten` first.\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.\n");
+ log("\n");
+ log(" -g1\n");
+ log(" debug information for non-localized public wires.\n");
+ log("\n");
}
+
void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
{
int opt_level = DEFAULT_OPT_LEVEL;
+ int debug_level = DEFAULT_DEBUG_LEVEL;
CxxrtlWorker worker;
log_header(design, "Executing CXXRTL backend.\n");
@@ -2332,6 +2398,14 @@ struct CxxrtlBackend : public Backend {
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;
@@ -2368,6 +2442,17 @@ struct CxxrtlBackend : public Backend {
log_cmd_error("Invalid optimization level %d.\n", opt_level);
}
+ switch (debug_level) {
+ // the highest level here must match DEFAULT_DEBUG_LEVEL
+ case 1:
+ worker.debug_info = true;
+ YS_FALLTHROUGH
+ case 0:
+ break;
+ default:
+ log_cmd_error("Invalid optimization level %d.\n", opt_level);
+ }
+
std::ofstream intf_f;
if (worker.split_intf) {
if (filename == "<stdout>")
diff --git a/backends/cxxrtl/cxxrtl.h b/backends/cxxrtl/cxxrtl.h
index 7b91742e0..14613afb0 100644
--- a/backends/cxxrtl/cxxrtl.h
+++ b/backends/cxxrtl/cxxrtl.h
@@ -49,6 +49,8 @@ namespace cxxrtl {
// invisible to the compiler, (b) we often operate on non-power-of-2 values and have to clear the high bits anyway.
// Therefore, using relatively wide chunks and clearing the high bits explicitly and only when we know they may be
// clobbered results in simpler generated code.
+typedef uint32_t chunk_t;
+
template<typename T>
struct chunk_traits {
static_assert(std::is_integral<T>::value && std::is_unsigned<T>::value,
@@ -65,7 +67,7 @@ template<size_t Bits>
struct value : public expr_base<value<Bits>> {
static constexpr size_t bits = Bits;
- using chunk = chunk_traits<uint32_t>;
+ using chunk = chunk_traits<chunk_t>;
static constexpr chunk::type msb_mask = (Bits % chunk::bits == 0) ? chunk::mask
: chunk::mask >> (chunk::bits - (Bits % chunk::bits));
@@ -712,6 +714,46 @@ struct metadata {
typedef std::map<std::string, metadata> metadata_map;
+// This structure is intended for consumption via foreign function interfaces, like Python's ctypes.
+// Because of this it uses a C-style layout that is easy to parse rather than more idiomatic C++.
+struct debug_item {
+ enum : uint32_t {
+ VALUE = 0,
+ WIRE = 1,
+ MEMORY = 2,
+ } type;
+
+ size_t width; // in bits
+ size_t depth; // 1 if `type != MEMORY`
+ chunk_t *curr;
+ chunk_t *next; // nullptr if `type == VALUE || type == MEMORY`
+
+ template<size_t Bits>
+ debug_item(value<Bits> &item) : type(VALUE), width(Bits), depth(1),
+ curr(item.data), next(nullptr) {
+ static_assert(sizeof(item) == value<Bits>::chunks * sizeof(chunk_t),
+ "value<Bits> is not compatible with C layout");
+ }
+
+ template<size_t Bits>
+ debug_item(wire<Bits> &item) : type(WIRE), width(Bits), depth(1),
+ curr(item.curr.data), next(item.next.data) {
+ static_assert(sizeof(item.curr) == value<Bits>::chunks * sizeof(chunk_t) &&
+ sizeof(item.next) == value<Bits>::chunks * sizeof(chunk_t),
+ "wire<Bits> is not compatible with C layout");
+ }
+
+ template<size_t Width>
+ debug_item(memory<Width> &item) : type(MEMORY), width(Width), depth(item.data.size()),
+ curr(item.data.empty() ? nullptr : item.data[0].data), next(nullptr) {
+ static_assert(sizeof(item.data[0]) == value<Width>::chunks * sizeof(chunk_t),
+ "memory<Width> is not compatible with C layout");
+ }
+};
+static_assert(std::is_standard_layout<debug_item>::value, "debug_item is not compatible with C layout");
+
+typedef std::map<std::string, debug_item> debug_items;
+
struct module {
module() {}
virtual ~module() {}
@@ -731,6 +773,8 @@ struct module {
} while (commit() && !converged);
return deltas;
}
+
+ virtual void debug_info(debug_items &items, std::string path = "") {}
};
} // namespace cxxrtl