Add esp_exception_decoder filter to device monitor

This filter can decode the crash traces emitted by Espressif devices.
Add '--filter=esp_exception_decoder' to monitor_flags to use it.

Fixes platformio/platform-espressif8266#31

Author: Tasssadar

platformio/commands/device.py

@@ -12,9 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import os
+import re
+import subprocess
 import sys
 from fnmatch import fnmatch
-from os import getcwd
 
 import click
 from serial.tools import miniterm
@@ -23,7 +25,8 @@
 from platformio.compat import dump_json_to_unicode
 from platformio.managers.platform import PlatformFactory
 from platformio.project.config import ProjectConfig
-from platformio.project.exception import NotPlatformIOProjectError
+from platformio.project.exception import PlatformioException, NotPlatformIOProjectError
+from platformio.project.helpers import load_project_ide_data
 
 
 @click.group(short_help="Monitor device or list existing")
@@ -108,6 +111,93 @@ def device_list(  # pylint: disable=too-many-branches
 
     return True
 
+class EspExceptionDecoder(miniterm.Transform):
+    NAME = "esp_exception_decoder"
+
+    project_dir = None
+    firmware_path = None
+    addr2line_path = None
+
+    @classmethod
+    def setup_paths(cls, project_dir, environment):
+        config = ProjectConfig.get_instance()
+        if not environment:
+            default_envs = config.default_envs()
+            if default_envs:
+                environment = default_envs[0]
+            else:
+                environment = config.envs()[0]
+
+        build_dir = config.get_optional_dir("build")
+        cls.project_dir = project_dir
+        if not cls.project_dir.endswith(os.path.sep):
+            cls.project_dir += os.path.sep
+
+        try:
+            data = load_project_ide_data(project_dir, environment)
+            cls.firmware_path = os.path.join(build_dir, environment, "firmware.elf")
+            if not os.path.isfile(cls.firmware_path):
+                sys.stderr.write("%s: firmware at %s does not exist, rebuild the project?\n" %
+                    (cls.__name__, cls.firmware_path))
+                return False
+
+            cc_path = data.get("cc_path", "")
+            if "-gcc" in cc_path:
+                path = cc_path.replace("-gcc", "-addr2line")
+                if os.path.isfile(path):
+                    cls.addr2line_path = path
+                    return True
+        except PlatformioException as e:
+            sys.stderr.write("%s: disabling, exception while looking for addr2line: %s\n" %
+                (cls.__name__, e))
+            return False
+        sys.stderr.write("%s: disabling, failed to find addr2line.\n" % cls.__name__)
+        return False
+
+    def __init__(self, *args, **kwargs):
+        super(EspExceptionDecoder, self).__init__(*args, **kwargs)
+
+        self.buffer = ""
+        self.backtrace_re = re.compile(r"^Backtrace: ((0x[0-9a-f]+:0x[0-9a-f]+ ?)+)\s*$")
+
+    def rx(self, text):
+        if self.addr2line_path is None:
+            return text
+
+        last = 0
+        while True:
+            idx = text.find("\n", last)
+            if idx == -1:
+                self.buffer += text[last:]
+                break
+
+            line = text[last:idx]
+            if self.buffer:
+                line = self.buffer + line
+                self.buffer = ""
+            last = idx+1
+
+            m = self.backtrace_re.match(line)
+            if m is None:
+                continue
+
+            trace = self.get_backtrace(m)
+            if len(trace) != "":
+                text = text[:idx+1] + trace + text[idx+1:]
+                last += len(trace)
+        return text
+
+    def get_backtrace(self, match):
+        trace = ""
+        try:
+            args = [ self.addr2line_path, "-fipC", "-e", self.firmware_path ]
+            for i, addr in enumerate(match.group(1).split()):
+                output = subprocess.check_output(args + [ addr ]).decode("utf-8")
+                trace += "  #%d in %s\n" % (i, output.strip().replace(self.project_dir, ""))
+        except subprocess.CalledProcessError as e:
+            sys.stderr.write("%s: failed to call %s: %s\n" %
+                (self.__class__.__name__, self.addr2line_path, e))
+        return trace
 
 @cli.command("monitor", short_help="Monitor device (Serial)")
 @click.option("--port", "-p", help="Port, a number or a device name")
@@ -165,7 +255,7 @@ def device_list(  # pylint: disable=too-many-branches
 @click.option(
     "-d",
     "--project-dir",
-    default=getcwd,
+    default=os.getcwd,
     type=click.Path(exists=True, file_okay=False, dir_okay=True, resolve_path=True),
 )
 @click.option(
@@ -217,6 +307,10 @@ def device_monitor(**kwargs):  # pylint: disable=too-many-branches
         ignore=("port", "baud", "rts", "dtr", "environment", "project_dir"),
     )
 
+    if any((EspExceptionDecoder.NAME in a for a in sys.argv)):
+        EspExceptionDecoder.setup_paths(kwargs["project_dir"], kwargs["environment"])
+        miniterm.TRANSFORMATIONS[EspExceptionDecoder.NAME] = EspExceptionDecoder
+
     try:
         miniterm.main(
             default_port=kwargs["port"],