Add monitor filter for decoding stack backtraces

Author: h2zero

monitor/filter_nable_exception_decoder.py

@@ -0,0 +1,206 @@
+#!/usr/bin/env python3
+# Copyright (c) 2014-present PlatformIO <contact@platformio.org>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Nable backtrace decoder monitor filter.
+
+This filter automatically decodes hard fault backtraces using addr2line,
+similar to the ESP32 exception decoder.
+
+Usage in platformio.ini:
+  [env:seeed_xiao_nrf52840_sense]
+  monitor_filters = nable_exception_decoder
+"""
+
+import os
+import re
+import subprocess
+import sys
+
+from platformio.exception import PlatformioException
+from platformio.public import (
+    DeviceMonitorFilterBase,
+    load_build_metadata,
+)
+
+# By design, __call__ is called inside miniterm and we can't pass context to it.
+# pylint: disable=attribute-defined-outside-init
+
+IS_WINDOWS = sys.platform.startswith("win")
+
+class NableExceptionDecoder(DeviceMonitorFilterBase):
+    """Nable backtrace decoder filter."""
+
+    NAME = "nable_exception_decoder"
+
+    # Pattern to match hex addresses in backtrace format like "  #0: 0x12345678"
+    ADDR_PATTERN = re.compile(r"(\s+#\d+:\s+)(0x[0-9a-fA-F]{8})")
+
+    def __call__(self):
+        """Initialize the filter."""
+        self.buffer = ""
+        self.backtrace_buffer = ""
+        self.in_backtrace = False
+        self.firmware_path = None
+        self.addr2line_path = None
+        self.enabled = self.setup_paths()
+
+        if not self.enabled:
+            sys.stderr.write(
+                "%s: failed to find addr2line or firmware. Backtrace decoding disabled.\n"
+                % self.__class__.__name__
+            )
+
+        if self.config.get("env:" + self.environment, "build_type") != "debug":
+            sys.stderr.write(
+                """
+Please build project in debug configuration to get more details about an exception.
+See https://docs.platformio.org/page/projectconf/build_configurations.html
+"""
+            )
+
+        return self
+
+    def setup_paths(self):
+        """Setup paths to firmware and addr2line tool."""
+        self.project_dir = os.path.abspath(self.project_dir)
+        try:
+            data = load_build_metadata(self.project_dir, self.environment, cache=True)
+
+            self.firmware_path = data["prog_path"]
+            if not os.path.isfile(self.firmware_path):
+                sys.stderr.write(
+                    "%s: firmware at %s does not exist, rebuild the project?\n"
+                    % (self.__class__.__name__, self.firmware_path)
+                )
+                return False
+
+            cc_path = data.get("cc_path", "")
+            if "eabi-gcc" in cc_path:
+                path = cc_path.replace("eabi-gcc", "eabi-addr2line")
+                if os.path.isfile(path):
+                    self.addr2line_path = path
+                    return True
+
+        except PlatformioException as e:
+            sys.stderr.write(
+                "%s: disabling, exception while looking for addr2line: %s\n"
+                % (self.__class__.__name__, e)
+            )
+            return False
+
+        sys.stderr.write(
+            "%s: disabling, failed to find addr2line.\n" % self.__class__.__name__
+        )
+        return False
+
+    def rx(self, text):
+        """Process received text and decode backtraces."""
+        if not self.enabled:
+            return text
+
+        output = ""
+        lines = text.splitlines(True)
+
+        for line in lines:
+            ended = line.endswith("\n") or line.endswith("\r")
+            raw = line.rstrip("\r\n") if ended else line
+            ending = line[len(raw):] if ended else ""
+
+            # Detect start of backtrace
+            if "Call Stack Backtrace:" in raw:
+                self.in_backtrace = True
+                self.backtrace_buffer = ""
+                output += raw + (ending or "\n")
+                continue
+
+            # Detect end of backtrace
+            if self.in_backtrace and "======" in raw:
+                self.in_backtrace = False
+                # Process complete backtrace
+                decoded = self.process_backtrace(self.backtrace_buffer)
+                if decoded:
+                    output += decoded
+                output += raw + (ending or "\n")
+                self.backtrace_buffer = ""
+                continue
+
+            # Buffer backtrace lines
+            if self.in_backtrace:
+                if ended:
+                    self.backtrace_buffer += raw + "\n"
+                else:
+                    self.backtrace_buffer += raw
+            else:
+                output += raw + ending
+
+        return output
+
+    def process_backtrace(self, backtrace_text):
+        """Process complete backtrace and decode all addresses."""
+        result = ""
+        lines = backtrace_text.split("\n")
+
+        for line in lines:
+            m = self.ADDR_PATTERN.search(line)
+            if m is not None:
+                decoded = self.build_backtrace(m.group(1), m.group(2))
+                if decoded:
+                    result += decoded
+            elif line.strip():
+                # Preserve non-address informational lines inside the backtrace
+                result += line + "\n"
+
+        return result
+
+    def tx(self, text):
+        """Process transmitted text (pass-through)."""
+        return text
+
+    def build_backtrace(self, prefix, addr):
+        """Build a formatted backtrace from a single address."""
+        enc = "mbcs" if IS_WINDOWS else "utf-8"
+        args = [self.addr2line_path, "-fipC", "-e", self.firmware_path]
+
+        try:
+            output = (
+                subprocess.check_output(args + [addr])
+                .decode(enc)
+                .strip()
+            )
+
+            # newlines happen with inlined methods
+            output = output.replace("\n", "\n     ")
+
+            output = self.strip_project_dir(output)
+            trace = "%s%s in %s\n" % (prefix, addr, output)
+            return trace
+
+        except subprocess.CalledProcessError as e:
+            sys.stderr.write(
+                "%s: failed to call %s: %s\n"
+                % (self.__class__.__name__, self.addr2line_path, e)
+            )
+            return "%s%s in ??:?\n" % (prefix, addr)
+
+    def strip_project_dir(self, trace):
+        """Remove project directory path from trace for cleaner output."""
+        while True:
+            idx = trace.find(self.project_dir)
+            if idx == -1:
+                break
+            trace = trace[:idx] + trace[idx + len(self.project_dir) + 1:]
+
+        return trace