rv/rvgen: replace % string formatting with f-strings

Replace all instances of percent-style string formatting with
f-strings across the rvgen codebase. This modernizes the string
formatting to use Python 3.6+ features, providing clearer and more
maintainable code while improving runtime performance.

The conversion handles all formatting cases including simple variable
substitution, multi-variable formatting, and complex format specifiers.
Dynamic width formatting is converted from "%*s" to "{var:>{width}}"
using proper alignment syntax. Template strings for generated C code
properly escape braces using double-brace syntax to produce literal
braces in the output.

F-strings provide approximately 2x performance improvement over percent
formatting and are the recommended approach in modern Python.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/20260223162407.147003-4-wander@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>

Author: walac

tools/verification/rvgen/__main__.py

@@ -42,7 +42,7 @@
 
     try:
         if params.subcmd == "monitor":
-            print("Opening and parsing the specification file %s" % params.spec)
+            print(f"Opening and parsing the specification file {params.spec}")
             if params.monitor_class == "da":
                 monitor = da2k(params.spec, params.monitor_type, vars(params))
             elif params.monitor_class == "ha":
@@ -58,11 +58,11 @@
         print(f"There was an error processing {params.spec}: {e}", file=sys.stderr)
         sys.exit(1)
 
-    print("Writing the monitor into the directory %s" % monitor.name)
+    print(f"Writing the monitor into the directory {monitor.name}")
     monitor.print_files()
     print("Almost done, checklist")
     if params.subcmd == "monitor":
-        print("  - Edit the %s/%s.c to add the instrumentation" % (monitor.name, monitor.name))
+        print(f"  - Edit the {monitor.name}/{monitor.name}.c to add the instrumentation")
         print(monitor.fill_tracepoint_tooltip())
     print(monitor.fill_makefile_tooltip())
     print(monitor.fill_kconfig_tooltip())

tools/verification/rvgen/rvgen/automata.py

@@ -79,11 +79,11 @@ def __get_model_name(self) -> str:
         basename = ntpath.basename(self.__dot_path)
         if not basename.endswith(".dot") and not basename.endswith(".gv"):
             print("not a dot file")
-            raise AutomataError("not a dot file: %s" % self.__dot_path)
+            raise AutomataError(f"not a dot file: {self.__dot_path}")
 
         model_name = ntpath.splitext(basename)[0]
         if model_name.__len__() == 0:
-            raise AutomataError("not a dot file: %s" % self.__dot_path)
+            raise AutomataError(f"not a dot file: {self.__dot_path}")
 
         return model_name
 
@@ -102,7 +102,7 @@ def __open_dot(self) -> list[str]:
         line = dot_lines[cursor].split()
 
         if (line[0] != "digraph") and (line[1] != "state_automaton"):
-            raise AutomataError("Not a valid .dot format: %s" % self.__dot_path)
+            raise AutomataError(f"Not a valid .dot format: {self.__dot_path}")
         else:
             cursor += 1
         return dot_lines

tools/verification/rvgen/rvgen/dot2c.py

@@ -29,17 +29,17 @@ def __init__(self, file_path, model_name=None):
 
     def __get_enum_states_content(self) -> list[str]:
         buff = []
-        buff.append("\t%s%s," % (self.initial_state, self.enum_suffix))
+        buff.append(f"\t{self.initial_state}{self.enum_suffix},")
         for state in self.states:
             if state != self.initial_state:
-                buff.append("\t%s%s," % (state, self.enum_suffix))
-        buff.append("\tstate_max%s," % (self.enum_suffix))
+                buff.append(f"\t{state}{self.enum_suffix},")
+        buff.append(f"\tstate_max{self.enum_suffix},")
 
         return buff
 
     def format_states_enum(self) -> list[str]:
         buff = []
-        buff.append("enum %s {" % self.enum_states_def)
+        buff.append(f"enum {self.enum_states_def} {{")
         buff += self.__get_enum_states_content()
         buff.append("};\n")
 
@@ -48,15 +48,15 @@ def format_states_enum(self) -> list[str]:
     def __get_enum_events_content(self) -> list[str]:
         buff = []
         for event in self.events:
-            buff.append("\t%s%s," % (event, self.enum_suffix))
+            buff.append(f"\t{event}{self.enum_suffix},")
 
-        buff.append("\tevent_max%s," % self.enum_suffix)
+        buff.append(f"\tevent_max{self.enum_suffix},")
 
         return buff
 
     def format_events_enum(self) -> list[str]:
         buff = []
-        buff.append("enum %s {" % self.enum_events_def)
+        buff.append(f"enum {self.enum_events_def} {{")
         buff += self.__get_enum_events_content()
         buff.append("};\n")
 
@@ -103,27 +103,27 @@ def get_minimun_type(self) -> str:
             min_type = "unsigned int"
 
         if self.states.__len__() > 1000000:
-            raise AutomataError("Too many states: %d" % self.states.__len__())
+            raise AutomataError(f"Too many states: {self.states.__len__()}")
 
         return min_type
 
     def format_automaton_definition(self) -> list[str]:
         min_type = self.get_minimun_type()
         buff = []
-        buff.append("struct %s {" % self.struct_automaton_def)
-        buff.append("\tchar *state_names[state_max%s];" % (self.enum_suffix))
-        buff.append("\tchar *event_names[event_max%s];" % (self.enum_suffix))
+        buff.append(f"struct {self.struct_automaton_def} {{")
+        buff.append(f"\tchar *state_names[state_max{self.enum_suffix}];")
+        buff.append(f"\tchar *event_names[event_max{self.enum_suffix}];")
         if self.is_hybrid_automata():
             buff.append(f"\tchar *env_names[env_max{self.enum_suffix}];")
-        buff.append("\t%s function[state_max%s][event_max%s];" % (min_type, self.enum_suffix, self.enum_suffix))
-        buff.append("\t%s initial_state;" % min_type)
-        buff.append("\tbool final_states[state_max%s];" % (self.enum_suffix))
+        buff.append(f"\t{min_type} function[state_max{self.enum_suffix}][event_max{self.enum_suffix}];")
+        buff.append(f"\t{min_type} initial_state;")
+        buff.append(f"\tbool final_states[state_max{self.enum_suffix}];")
         buff.append("};\n")
         return buff
 
     def format_aut_init_header(self) -> list[str]:
         buff = []
-        buff.append("static const struct %s %s = {" % (self.struct_automaton_def, self.var_automaton_def))
+        buff.append(f"static const struct {self.struct_automaton_def} {self.var_automaton_def} = {{")
         return buff
 
     def __get_string_vector_per_line_content(self, entries: list[str]) -> str:
@@ -179,9 +179,9 @@ def get_aut_init_function(self) -> str:
                     next_state = self.function[x][y] + self.enum_suffix
 
                 if linetoolong:
-                    line += "\t\t\t%s" % next_state
+                    line += f"\t\t\t{next_state}"
                 else:
-                    line += "%*s" % (maxlen, next_state)
+                    line += f"{next_state:>{maxlen}}"
                 if y != nr_events-1:
                     line += ",\n" if linetoolong else ", "
                 else:
@@ -225,7 +225,7 @@ def get_aut_init_final_states(self) -> str:
 
     def format_aut_init_final_states(self) -> list[str]:
        buff = []
-       buff.append("\t.final_states = { %s }," % self.get_aut_init_final_states())
+       buff.append(f"\t.final_states = {{ {self.get_aut_init_final_states()} }},")
 
        return buff
 
@@ -241,7 +241,7 @@ def format_aut_init_footer(self) -> list[str]:
 
     def format_invalid_state(self) -> list[str]:
         buff = []
-        buff.append("#define %s state_max%s\n" % (self.invalid_state_str, self.enum_suffix))
+        buff.append(f"#define {self.invalid_state_str} state_max{self.enum_suffix}\n")
 
         return buff
 

tools/verification/rvgen/rvgen/dot2k.py

@@ -21,7 +21,8 @@ def __init__(self, file_path, MonitorType, extra_params={}):
         self.monitor_type = MonitorType
         Monitor.__init__(self, extra_params)
         Dot2c.__init__(self, file_path, extra_params.get("model_name"))
-        self.enum_suffix = "_%s" % self.name
+        self.enum_suffix = f"_{self.name}"
+        self.enum_suffix = f"_{self.name}"
         self.monitor_class = extra_params["monitor_class"]
 
     def fill_monitor_type(self) -> str:
@@ -35,7 +36,7 @@ def fill_tracepoint_handlers_skel(self) -> str:
         buff = []
         buff += self._fill_hybrid_definitions()
         for event in self.events:
-            buff.append("static void handle_%s(void *data, /* XXX: fill header */)" % event)
+            buff.append(f"static void handle_{event}(void *data, /* XXX: fill header */)")
             buff.append("{")
             handle = "handle_event"
             if self.is_start_event(event):
@@ -46,39 +47,39 @@ def fill_tracepoint_handlers_skel(self) -> str:
                 handle = "handle_start_run_event"
             if self.monitor_type == "per_task":
                 buff.append("\tstruct task_struct *p = /* XXX: how do I get p? */;");
-                buff.append("\tda_%s(p, %s%s);" % (handle, event, self.enum_suffix));
+                buff.append(f"\tda_{handle}(p, {event}{self.enum_suffix});");
             elif self.monitor_type == "per_obj":
                 buff.append("\tint id = /* XXX: how do I get the id? */;")
                 buff.append("\tmonitor_target t = /* XXX: how do I get t? */;")
                 buff.append(f"\tda_{handle}(id, t, {event}{self.enum_suffix});")
             else:
-                buff.append("\tda_%s(%s%s);" % (handle, event, self.enum_suffix));
+                buff.append(f"\tda_{handle}({event}{self.enum_suffix});");
             buff.append("}")
             buff.append("")
         return '\n'.join(buff)
 
     def fill_tracepoint_attach_probe(self) -> str:
         buff = []
         for event in self.events:
-            buff.append("\trv_attach_trace_probe(\"%s\", /* XXX: tracepoint */, handle_%s);" % (self.name, event))
+            buff.append(f"\trv_attach_trace_probe(\"{self.name}\", /* XXX: tracepoint */, handle_{event});")
         return '\n'.join(buff)
 
     def fill_tracepoint_detach_helper(self) -> str:
         buff = []
         for event in self.events:
-            buff.append("\trv_detach_trace_probe(\"%s\", /* XXX: tracepoint */, handle_%s);" % (self.name, event))
+            buff.append(f"\trv_detach_trace_probe(\"{self.name}\", /* XXX: tracepoint */, handle_{event});")
         return '\n'.join(buff)
 
     def fill_model_h_header(self) -> list[str]:
         buff = []
         buff.append("/* SPDX-License-Identifier: GPL-2.0 */")
         buff.append("/*")
-        buff.append(" * Automatically generated C representation of %s automaton" % (self.name))
+        buff.append(f" * Automatically generated C representation of {self.name} automaton")
         buff.append(" * For further information about this format, see kernel documentation:")
         buff.append(" *   Documentation/trace/rv/deterministic_automata.rst")
         buff.append(" */")
         buff.append("")
-        buff.append("#define MONITOR_NAME %s" % (self.name))
+        buff.append(f"#define MONITOR_NAME {self.name}")
         buff.append("")
 
         return buff
@@ -87,11 +88,11 @@ def fill_model_h(self) -> str:
         #
         # Adjust the definition names
         #
-        self.enum_states_def = "states_%s" % self.name
-        self.enum_events_def = "events_%s" % self.name
+        self.enum_states_def = f"states_{self.name}"
+        self.enum_events_def = f"events_{self.name}"
         self.enum_envs_def = f"envs_{self.name}"
-        self.struct_automaton_def = "automaton_%s" % self.name
-        self.var_automaton_def = "automaton_%s" % self.name
+        self.struct_automaton_def = f"automaton_{self.name}"
+        self.var_automaton_def = f"automaton_{self.name}"
 
         buff = self.fill_model_h_header()
         buff += self.format_model()
@@ -135,8 +136,8 @@ def fill_tracepoint_args_skel(self, tp_type: str) -> str:
             tp_args.insert(0, tp_args_id)
         tp_proto_c = ", ".join([a+b for a,b in tp_args])
         tp_args_c = ", ".join([b for a,b in tp_args])
-        buff.append("	     TP_PROTO(%s)," % tp_proto_c)
-        buff.append("	     TP_ARGS(%s)" % tp_args_c)
+        buff.append(f"	     TP_PROTO({tp_proto_c}),")
+        buff.append(f"	     TP_ARGS({tp_args_c})")
         return '\n'.join(buff)
 
     def _fill_hybrid_definitions(self) -> list:

tools/verification/rvgen/rvgen/generator.py

@@ -40,7 +40,7 @@ def __fill_rv_kernel_dir(self):
         if platform.system() != "Linux":
             raise OSError("I can only run on Linux.")
 
-        kernel_path = os.path.join("/lib/modules/%s/build" % platform.release(), self.rv_dir)
+        kernel_path = os.path.join(f"/lib/modules/{platform.release()}/build", self.rv_dir)
 
         # if the current kernel is from a distro this may not be a full kernel tree
         # verify that one of the files we are going to modify is available
@@ -69,11 +69,11 @@ def _read_template_file(self, file):
             return self._read_file(path)
 
     def fill_parent(self):
-        return "&rv_%s" % self.parent if self.parent else "NULL"
+        return f"&rv_{self.parent}" if self.parent else "NULL"
 
     def fill_include_parent(self):
         if self.parent:
-            return "#include <monitors/%s/%s.h>\n" % (self.parent, self.parent)
+            return f"#include <monitors/{self.parent}/{self.parent}.h>\n"
         return ""
 
     def fill_tracepoint_handlers_skel(self):
@@ -119,7 +119,7 @@ def fill_monitor_deps(self):
         buff = []
         buff.append("	# XXX: add dependencies if there")
         if self.parent:
-            buff.append("	depends on RV_MON_%s" % self.parent.upper())
+            buff.append(f"	depends on RV_MON_{self.parent.upper()}")
             buff.append("	default y")
         return '\n'.join(buff)
 
@@ -145,50 +145,49 @@ def fill_tracepoint_tooltip(self):
         monitor_class_type = self.fill_monitor_class_type()
         if self.auto_patch:
             self._patch_file("rv_trace.h",
-                            "// Add new monitors based on CONFIG_%s here" % monitor_class_type,
-                            "#include <monitors/%s/%s_trace.h>" % (self.name, self.name))
-            return "  - Patching %s/rv_trace.h, double check the result" % self.rv_dir
+                            f"// Add new monitors based on CONFIG_{monitor_class_type} here",
+                            f"#include <monitors/{self.name}/{self.name}_trace.h>")
+            return f"  - Patching {self.rv_dir}/rv_trace.h, double check the result"
 
-        return """  - Edit %s/rv_trace.h:
-Add this line where other tracepoints are included and %s is defined:
-#include <monitors/%s/%s_trace.h>
-""" % (self.rv_dir, monitor_class_type, self.name, self.name)
+        return f"""  - Edit {self.rv_dir}/rv_trace.h:
+Add this line where other tracepoints are included and {monitor_class_type} is defined:
+#include <monitors/{self.name}/{self.name}_trace.h>
+"""
 
     def _kconfig_marker(self, container=None) -> str:
-        return "# Add new %smonitors here" % (container + " "
-                                              if container else "")
+        return f"# Add new {container + ' ' if container else ''}monitors here"
 
     def fill_kconfig_tooltip(self):
         if self.auto_patch:
             # monitors with a container should stay together in the Kconfig
             self._patch_file("Kconfig",
                              self._kconfig_marker(self.parent),
-                            "source \"kernel/trace/rv/monitors/%s/Kconfig\"" % (self.name))
-            return "  - Patching %s/Kconfig, double check the result" % self.rv_dir
+                            f"source \"kernel/trace/rv/monitors/{self.name}/Kconfig\"")
+            return f"  - Patching {self.rv_dir}/Kconfig, double check the result"
 
-        return """  - Edit %s/Kconfig:
+        return f"""  - Edit {self.rv_dir}/Kconfig:
 Add this line where other monitors are included:
-source \"kernel/trace/rv/monitors/%s/Kconfig\"
-""" % (self.rv_dir, self.name)
+source \"kernel/trace/rv/monitors/{self.name}/Kconfig\"
+"""
 
     def fill_makefile_tooltip(self):
         name = self.name
         name_up = name.upper()
         if self.auto_patch:
             self._patch_file("Makefile",
                             "# Add new monitors here",
-                            "obj-$(CONFIG_RV_MON_%s) += monitors/%s/%s.o" % (name_up, name, name))
-            return "  - Patching %s/Makefile, double check the result" % self.rv_dir
+                            f"obj-$(CONFIG_RV_MON_{name_up}) += monitors/{name}/{name}.o")
+            return f"  - Patching {self.rv_dir}/Makefile, double check the result"
 
-        return """  - Edit %s/Makefile:
+        return f"""  - Edit {self.rv_dir}/Makefile:
 Add this line where other monitors are included:
-obj-$(CONFIG_RV_MON_%s) += monitors/%s/%s.o
-""" % (self.rv_dir, name_up, name, name)
+obj-$(CONFIG_RV_MON_{name_up}) += monitors/{name}/{name}.o
+"""
 
     def fill_monitor_tooltip(self):
         if self.auto_patch:
-            return "  - Monitor created in %s/monitors/%s" % (self.rv_dir, self. name)
-        return "  - Move %s/ to the kernel's monitor directory (%s/monitors)" % (self.name, self.rv_dir)
+            return f"  - Monitor created in {self.rv_dir}/monitors/{self.name}"
+        return f"  - Move {self.name}/ to the kernel's monitor directory ({self.rv_dir}/monitors)"
 
     def __create_directory(self):
         path = self.name
@@ -205,13 +204,13 @@ def __write_file(self, file_name, content):
         file.close()
 
     def _create_file(self, file_name, content):
-        path = "%s/%s" % (self.name, file_name)
+        path = f"{self.name}/{file_name}"
         if self.auto_patch:
             path = os.path.join(self.rv_dir, "monitors", path)
         self.__write_file(path, content)
 
     def __get_main_name(self):
-        path = "%s/%s" % (self.name, "main.c")
+        path = f"{self.name}/main.c"
         if not os.path.exists(path):
             return "main.c"
         return "__main.c"
@@ -221,11 +220,11 @@ def print_files(self):
 
         self.__create_directory()
 
-        path = "%s.c" % self.name
+        path = f"{self.name}.c"
         self._create_file(path, main_c)
 
         model_h = self.fill_model_h()
-        path = "%s.h" % self.name
+        path = f"{self.name}.h"
         self._create_file(path, model_h)
 
         kconfig = self.fill_kconfig()
@@ -258,5 +257,5 @@ def fill_trace_h(self):
     def print_files(self):
         super().print_files()
         trace_h = self.fill_trace_h()
-        path = "%s_trace.h" % self.name
+        path = f"{self.name}_trace.h"
         self._create_file(path, trace_h)