diff --git a/backends/cxxrtl/cxxrtl_backend.cc b/backends/cxxrtl/cxxrtl_backend.cc index 1ab865a279c..2c35a1943e2 100644 --- a/backends/cxxrtl/cxxrtl_backend.cc +++ b/backends/cxxrtl/cxxrtl_backend.cc @@ -2115,19 +2115,19 @@ struct CxxrtlWorker { 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"; + f << indent << "if (" << mangle(wire) << ".commit(observer)) 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"; + f << indent << "if (" << mangle(&mem) << ".commit(observer)) 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 << "if (" << mangle(cell) << access << "commit(observer)) changed = true;\n"; } } f << indent << "return changed;\n"; @@ -2146,7 +2146,7 @@ struct CxxrtlWorker { if (!metadata_item.first.isPublic()) continue; if (metadata_item.second.size() > 64 && (metadata_item.second.flags & RTLIL::CONST_FLAG_STRING) == 0) { - f << indent << "/* attribute " << metadata_item.first.str().substr(1) << " is over 64 bits wide */"; + f << indent << "/* attribute " << metadata_item.first.str().substr(1) << " is over 64 bits wide */\n"; continue; } f << indent << "{ " << escape_cxx_string(metadata_item.first.str().substr(1)) << ", "; @@ -2371,16 +2371,22 @@ struct CxxrtlWorker { dump_eval_method(module); f << indent << "}\n"; f << "\n"; - f << indent << "bool commit() override {\n"; + f << indent << "template\n"; + f << indent << "bool commit(ObserverT &observer) {\n"; dump_commit_method(module); f << indent << "}\n"; f << "\n"; + f << indent << "bool commit() override {\n"; + f << indent << indent << "null_observer observer;\n"; + f << indent << indent << "return commit<>(observer);\n"; + f << indent << "}\n"; if (debug_info) { + f << "\n"; f << indent << "void debug_info(debug_items &items, std::string path = \"\") override {\n"; dump_debug_info_method(module); f << indent << "}\n"; - f << "\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"; @@ -2457,8 +2463,18 @@ struct CxxrtlWorker { f << indent << "};\n"; f << "\n"; f << indent << "void reset() override;\n"; + f << "\n"; f << indent << "bool eval() override;\n"; - f << indent << "bool commit() override;\n"; + f << "\n"; + f << indent << "template\n"; + f << indent << "bool commit(ObserverT &observer) {\n"; + dump_commit_method(module); + f << indent << "}\n"; + f << "\n"; + f << indent << "bool commit() override {\n"; + f << indent << indent << "null_observer observer;\n"; + f << indent << indent << "return commit<>(observer);\n"; + f << indent << "}\n"; if (debug_info) { if (debug_eval) { f << "\n"; @@ -2490,24 +2506,20 @@ struct CxxrtlWorker { 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 << "\n"; f << indent << "void " << mangle(module) << "::debug_eval() {\n"; dump_debug_eval_method(module); f << indent << "}\n"; - f << "\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"; } + f << "\n"; } void dump_design(RTLIL::Design *design) @@ -3267,6 +3279,8 @@ struct CxxrtlBackend : public Backend { log(" wire<8> p_o_data;\n"); log("\n"); log(" bool eval() override;\n"); + log(" template\n"); + log(" bool commit(ObserverT &observer);\n"); log(" bool commit() override;\n"); log("\n"); log(" static std::unique_ptr\n"); diff --git a/backends/cxxrtl/runtime/cxxrtl/cxxrtl.h b/backends/cxxrtl/runtime/cxxrtl/cxxrtl.h index 2d545128754..f69d5a9ce93 100644 --- a/backends/cxxrtl/runtime/cxxrtl/cxxrtl.h +++ b/backends/cxxrtl/runtime/cxxrtl/cxxrtl.h @@ -837,6 +837,29 @@ std::ostream &operator<<(std::ostream &os, const value_formatted &vf) return os; } +// An object that can be passed to a `commit()` method in order to produce a replay log of every +// state change in the simulation. +struct observer { + // Called when a `commit()` method for a wire is about to update the `chunks` chunks at `base` + // with `chunks` chunks at `value` that have a different bit pattern. It is guaranteed that + // `chunks` is equal to the wire chunk count and `base` points to the first chunk. + virtual void on_commit(size_t chunks, const chunk_t *base, const chunk_t *value) = 0; + + // Called when a `commit()` method for a memory is about to update the `chunks` chunks at + // `&base[chunks * index]` with `chunks` chunks at `value` that have a different bit pattern. + // It is guaranteed that `chunks` covers is equal to the memory element chunk count and `base` + // points to the first chunk of the first element of the memory. + virtual void on_commit(size_t chunks, const chunk_t *base, const chunk_t *value, size_t index) = 0; +}; + +// The `null_observer` class has the same interface as `observer`, but has no invocation overhead, +// since its methods are final and have no implementation. This allows the observer feature to be +// zero-cost when not in use. +struct null_observer final: observer { + void on_commit(size_t chunks, const chunk_t *base, const chunk_t *value) override {} + void on_commit(size_t chunks, const chunk_t *base, const chunk_t *value, size_t index) override {} +}; + template struct wire { static constexpr size_t bits = Bits; @@ -871,8 +894,14 @@ struct wire { next.template set(other); } - bool commit() { + // This method intentionally takes a mandatory argument (to make it more difficult to misuse in + // black box implementations, leading to missed observer events). It is generic over its argument + // to make sure the `on_commit` call is devirtualized. This is somewhat awkward but lets us keep + // a single implementation for both this method and the one in `memory`. + template + bool commit(ObserverT &observer) { if (curr != next) { + observer.on_commit(curr.chunks, curr.data, next.data); curr = next; return true; } @@ -946,12 +975,17 @@ struct memory { write { index, val, mask, priority }); } - bool commit() { + // See the note for `wire::commit()`. + template + bool commit(ObserverT &observer) { bool changed = false; for (const write &entry : write_queue) { value elem = data[entry.index]; elem = elem.update(entry.val, entry.mask); - changed |= (data[entry.index] != elem); + if (data[entry.index] != elem) { + observer.on_commit(value::chunks, data[0].data, elem.data, entry.index); + changed |= true; + } data[entry.index] = elem; } write_queue.clear();