[lldb-dap] Improve stackTrace and exceptionInfo DAP request handlers (#105905)

Refactoring `stackTrace` to perform frame look ups in a more on-demand
fashion to improve overall performance.

Additionally adding additional information to the `exceptionInfo`
request to report exception stacks there instead of merging the
exception stack into the stack trace. The `exceptionInfo` request is
only called if a stop event occurs with `reason='exception'`, which
should mitigate the performance of `SBThread::GetCurrentException`
calls.

Adding unit tests for exception handling and stack trace supporting.

Author: ashgti

lldb/packages/Python/lldbsuite/test/lldbplatformutil.py

@@ -181,6 +181,22 @@ def findMainThreadCheckerDylib():
     return ""
 
 
+def findBacktraceRecordingDylib():
+    if not platformIsDarwin():
+        return ""
+
+    if getPlatform() in lldbplatform.translate(lldbplatform.darwin_embedded):
+        return "/Developer/usr/lib/libBacktraceRecording.dylib"
+
+    with os.popen("xcode-select -p") as output:
+        xcode_developer_path = output.read().strip()
+        mtc_dylib_path = "%s/usr/lib/libBacktraceRecording.dylib" % xcode_developer_path
+        if os.path.isfile(mtc_dylib_path):
+            return mtc_dylib_path
+
+    return ""
+
+
 class _PlatformContext(object):
     """Value object class which contains platform-specific options."""
 

lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py

@@ -707,6 +707,17 @@ def request_evaluate(self, expression, frameIndex=0, threadId=None, context=None
         }
         return self.send_recv(command_dict)
 
+    def request_exceptionInfo(self, threadId=None):
+        if threadId is None:
+            threadId = self.get_thread_id()
+        args_dict = {"threadId": threadId}
+        command_dict = {
+            "command": "exceptionInfo",
+            "type": "request",
+            "arguments": args_dict,
+        }
+        return self.send_recv(command_dict)
+
     def request_initialize(self, sourceInitFile):
         command_dict = {
             "command": "initialize",
@@ -754,6 +765,7 @@ def request_launch(
         runInTerminal=False,
         postRunCommands=None,
         enableAutoVariableSummaries=False,
+        enableDisplayExtendedBacktrace=False,
         enableSyntheticChildDebugging=False,
         commandEscapePrefix=None,
         customFrameFormat=None,
@@ -806,6 +818,7 @@ def request_launch(
 
         args_dict["enableAutoVariableSummaries"] = enableAutoVariableSummaries
         args_dict["enableSyntheticChildDebugging"] = enableSyntheticChildDebugging
+        args_dict["enableDisplayExtendedBacktrace"] = enableDisplayExtendedBacktrace
         args_dict["commandEscapePrefix"] = commandEscapePrefix
         command_dict = {"command": "launch", "type": "request", "arguments": args_dict}
         response = self.send_recv(command_dict)

lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py

@@ -103,13 +103,14 @@ def verify_breakpoint_hit(self, breakpoint_ids):
                         return
         self.assertTrue(False, "breakpoint not hit")
 
-    def verify_stop_exception_info(self, expected_description):
+    def verify_stop_exception_info(self, expected_description, timeout=timeoutval):
         """Wait for the process we are debugging to stop, and verify the stop
         reason is 'exception' and that the description matches
         'expected_description'
         """
-        stopped_events = self.dap_server.wait_for_stopped()
+        stopped_events = self.dap_server.wait_for_stopped(timeout=timeout)
         for stopped_event in stopped_events:
+            print("stopped_event", stopped_event)
             if "body" in stopped_event:
                 body = stopped_event["body"]
                 if "reason" not in body:
@@ -180,6 +181,10 @@ def get_stackFrames(self, threadId=None, startFrame=None, levels=None, dump=Fals
         )
         return stackFrames
 
+    def get_exceptionInfo(self, threadId=None):
+        response = self.dap_server.request_exceptionInfo(threadId=threadId)
+        return self.get_dict_value(response, ["body"])
+
     def get_source_and_line(self, threadId=None, frameIndex=0):
         stackFrames = self.get_stackFrames(
             threadId=threadId, startFrame=frameIndex, levels=1
@@ -381,6 +386,7 @@ def launch(
         expectFailure=False,
         postRunCommands=None,
         enableAutoVariableSummaries=False,
+        enableDisplayExtendedBacktrace=False,
         enableSyntheticChildDebugging=False,
         commandEscapePrefix=None,
         customFrameFormat=None,
@@ -422,6 +428,7 @@ def cleanup():
             runInTerminal=runInTerminal,
             postRunCommands=postRunCommands,
             enableAutoVariableSummaries=enableAutoVariableSummaries,
+            enableDisplayExtendedBacktrace=enableDisplayExtendedBacktrace,
             enableSyntheticChildDebugging=enableSyntheticChildDebugging,
             commandEscapePrefix=commandEscapePrefix,
             customFrameFormat=customFrameFormat,
@@ -461,6 +468,7 @@ def build_and_launch(
         postRunCommands=None,
         lldbDAPEnv=None,
         enableAutoVariableSummaries=False,
+        enableDisplayExtendedBacktrace=False,
         enableSyntheticChildDebugging=False,
         commandEscapePrefix=None,
         customFrameFormat=None,
@@ -497,6 +505,7 @@ def build_and_launch(
             postRunCommands=postRunCommands,
             enableAutoVariableSummaries=enableAutoVariableSummaries,
             enableSyntheticChildDebugging=enableSyntheticChildDebugging,
+            enableDisplayExtendedBacktrace=enableDisplayExtendedBacktrace,
             commandEscapePrefix=commandEscapePrefix,
             customFrameFormat=customFrameFormat,
             customThreadFormat=customThreadFormat,

lldb/test/API/tools/lldb-dap/exception/Makefile

@@ -1,3 +1,3 @@
-CXX_SOURCES := main.cpp
+C_SOURCES := main.c
 
 include Makefile.rules

lldb/test/API/tools/lldb-dap/exception/TestDAP_exception.py

@@ -1,5 +1,5 @@
 """
-Test exception behavior in DAP
+Test exception behavior in DAP with signal.
 """
 
 
@@ -16,8 +16,10 @@ def test_stopped_description(self):
         event.
         """
         program = self.getBuildArtifact("a.out")
-        print("test_stopped_description called", flush=True)
         self.build_and_launch(program)
-
         self.dap_server.request_continue()
         self.assertTrue(self.verify_stop_exception_info("signal SIGABRT"))
+        exceptionInfo = self.get_exceptionInfo()
+        self.assertEqual(exceptionInfo["breakMode"], "always")
+        self.assertEqual(exceptionInfo["description"], "signal SIGABRT")
+        self.assertEqual(exceptionInfo["exceptionId"], "signal")

lldb/test/API/tools/lldb-dap/exception/cpp/Makefile

@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules

lldb/test/API/tools/lldb-dap/exception/cpp/TestDAP_exception_cpp.py

@@ -0,0 +1,26 @@
+"""
+Test exception behavior in DAP with c++ throw.
+"""
+
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+import lldbdap_testcase
+
+
+class TestDAP_exception_cpp(lldbdap_testcase.DAPTestCaseBase):
+    @skipIfWindows
+    def test_stopped_description(self):
+        """
+        Test that exception description is shown correctly in stopped
+        event.
+        """
+        program = self.getBuildArtifact("a.out")
+        self.build_and_launch(program)
+        self.dap_server.request_continue()
+        self.assertTrue(self.verify_stop_exception_info("signal SIGABRT"))
+        exceptionInfo = self.get_exceptionInfo()
+        self.assertEqual(exceptionInfo["breakMode"], "always")
+        self.assertEqual(exceptionInfo["description"], "signal SIGABRT")
+        self.assertEqual(exceptionInfo["exceptionId"], "signal")
+        self.assertIsNotNone(exceptionInfo["details"])

lldb/test/API/tools/lldb-dap/exception/cpp/main.cpp

@@ -0,0 +1,6 @@
+#include <stdexcept>
+
+int main(int argc, char const *argv[]) {
+  throw std::invalid_argument("throwing exception for testing");
+  return 0;
+}

lldb/test/API/tools/lldb-dap/exception/main.cpp renamed to lldb/test/API/tools/lldb-dap/exception/main.c

@@ -1,6 +1,6 @@
 #include <signal.h>
 
-int main() {
+int main(int argc, char const *argv[]) {
   raise(SIGABRT);
   return 0;
 }

lldb/test/API/tools/lldb-dap/exception/objc/Makefile

@@ -0,0 +1,9 @@
+OBJC_SOURCES := main.m
+
+CFLAGS_EXTRAS := -w
+
+USE_SYSTEM_STDLIB := 1
+
+LD_EXTRAS := -framework Foundation
+
+include Makefile.rules