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

John Harrison via lldb-commits lldb-commits at lists.llvm.org
Wed Aug 28 14:27:23 PDT 2024


https://github.com/ashgti updated https://github.com/llvm/llvm-project/pull/105905

>From ebcf4842c7d6c5ac0da4976c9cffb68bc3b22807 Mon Sep 17 00:00:00 2001
From: John Harrison <harjohn at google.com>
Date: Fri, 23 Aug 2024 16:04:44 -0700
Subject: [PATCH 1/5] [lldb-dap] Improve `stackTrace` and `exceptionInfo` DAP
 request handlers.

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.
---
 .../Python/lldbsuite/test/lldbplatformutil.py |  16 ++
 .../test/tools/lldb-dap/dap_server.py         |  11 +
 .../test/tools/lldb-dap/lldbdap_testcase.py   |   9 +-
 .../API/tools/lldb-dap/exception/Makefile     |   2 +-
 .../lldb-dap/exception/TestDAP_exception.py   |   8 +-
 .../API/tools/lldb-dap/exception/cpp/Makefile |   3 +
 .../exception/cpp/TestDAP_exception_cpp.py    |  26 ++
 .../API/tools/lldb-dap/exception/cpp/main.cpp |   6 +
 .../lldb-dap/exception/{main.cpp => main.c}   |   2 +-
 .../tools/lldb-dap/exception/objc/Makefile    |   9 +
 .../exception/objc/TestDAP_exception_objc.py  |  27 ++
 .../API/tools/lldb-dap/exception/objc/main.m  |   8 +
 .../lldb-dap/extendedStackTrace/Makefile      |   5 +
 .../TestDAP_extendedStackTrace.py             |  69 +++++
 .../tools/lldb-dap/extendedStackTrace/main.m  |  28 ++
 .../lldb-dap/stackTrace/TestDAP_stackTrace.py |   4 +-
 .../TestDAP_stackTraceMissingFunctionName.py  |   5 -
 lldb/tools/lldb-dap/DAP.cpp                   |   1 -
 lldb/tools/lldb-dap/DAP.h                     |   2 +-
 lldb/tools/lldb-dap/JSONUtils.cpp             |  40 +++
 lldb/tools/lldb-dap/JSONUtils.h               |   3 +
 lldb/tools/lldb-dap/lldb-dap.cpp              | 253 +++++++++++++-----
 22 files changed, 449 insertions(+), 88 deletions(-)
 create mode 100644 lldb/test/API/tools/lldb-dap/exception/cpp/Makefile
 create mode 100644 lldb/test/API/tools/lldb-dap/exception/cpp/TestDAP_exception_cpp.py
 create mode 100644 lldb/test/API/tools/lldb-dap/exception/cpp/main.cpp
 rename lldb/test/API/tools/lldb-dap/exception/{main.cpp => main.c} (56%)
 create mode 100644 lldb/test/API/tools/lldb-dap/exception/objc/Makefile
 create mode 100644 lldb/test/API/tools/lldb-dap/exception/objc/TestDAP_exception_objc.py
 create mode 100644 lldb/test/API/tools/lldb-dap/exception/objc/main.m
 create mode 100644 lldb/test/API/tools/lldb-dap/extendedStackTrace/Makefile
 create mode 100644 lldb/test/API/tools/lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py
 create mode 100644 lldb/test/API/tools/lldb-dap/extendedStackTrace/main.m

diff --git a/lldb/packages/Python/lldbsuite/test/lldbplatformutil.py b/lldb/packages/Python/lldbsuite/test/lldbplatformutil.py
index 602e15d207e94a..3d8c713562e9bf 100644
--- a/lldb/packages/Python/lldbsuite/test/lldbplatformutil.py
+++ b/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."""
 
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
index 874383a13e2bb6..167142779cf12c 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
+++ b/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",
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
index 86eba355da83db..40d61636380588 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
+++ b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
@@ -100,13 +100,14 @@ 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:
@@ -177,6 +178,10 @@ 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
diff --git a/lldb/test/API/tools/lldb-dap/exception/Makefile b/lldb/test/API/tools/lldb-dap/exception/Makefile
index 99998b20bcb050..10495940055b63 100644
--- a/lldb/test/API/tools/lldb-dap/exception/Makefile
+++ b/lldb/test/API/tools/lldb-dap/exception/Makefile
@@ -1,3 +1,3 @@
-CXX_SOURCES := main.cpp
+C_SOURCES := main.c
 
 include Makefile.rules
diff --git a/lldb/test/API/tools/lldb-dap/exception/TestDAP_exception.py b/lldb/test/API/tools/lldb-dap/exception/TestDAP_exception.py
index 8c2c0154ba65c0..39d73737b7e8c0 100644
--- a/lldb/test/API/tools/lldb-dap/exception/TestDAP_exception.py
+++ b/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")
diff --git a/lldb/test/API/tools/lldb-dap/exception/cpp/Makefile b/lldb/test/API/tools/lldb-dap/exception/cpp/Makefile
new file mode 100644
index 00000000000000..99998b20bcb050
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/exception/cpp/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules
diff --git a/lldb/test/API/tools/lldb-dap/exception/cpp/TestDAP_exception_cpp.py b/lldb/test/API/tools/lldb-dap/exception/cpp/TestDAP_exception_cpp.py
new file mode 100644
index 00000000000000..6471e2b87251a7
--- /dev/null
+++ b/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"])
diff --git a/lldb/test/API/tools/lldb-dap/exception/cpp/main.cpp b/lldb/test/API/tools/lldb-dap/exception/cpp/main.cpp
new file mode 100644
index 00000000000000..39d89b95319a8c
--- /dev/null
+++ b/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;
+}
diff --git a/lldb/test/API/tools/lldb-dap/exception/main.cpp b/lldb/test/API/tools/lldb-dap/exception/main.c
similarity index 56%
rename from lldb/test/API/tools/lldb-dap/exception/main.cpp
rename to lldb/test/API/tools/lldb-dap/exception/main.c
index b940d07c6f2bb3..a653ac5d82aa3a 100644
--- a/lldb/test/API/tools/lldb-dap/exception/main.cpp
+++ b/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;
 }
diff --git a/lldb/test/API/tools/lldb-dap/exception/objc/Makefile b/lldb/test/API/tools/lldb-dap/exception/objc/Makefile
new file mode 100644
index 00000000000000..9b6528337cb9d8
--- /dev/null
+++ b/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
diff --git a/lldb/test/API/tools/lldb-dap/exception/objc/TestDAP_exception_objc.py b/lldb/test/API/tools/lldb-dap/exception/objc/TestDAP_exception_objc.py
new file mode 100644
index 00000000000000..777d55f48e8504
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/exception/objc/TestDAP_exception_objc.py
@@ -0,0 +1,27 @@
+"""
+Test exception behavior in DAP with obj-c throw.
+"""
+
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+import lldbdap_testcase
+
+
+class TestDAP_exception_objc(lldbdap_testcase.DAPTestCaseBase):
+    @skipUnlessDarwin
+    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"))
+        exception_info = self.get_exceptionInfo()
+        self.assertEqual(exception_info["breakMode"], "always")
+        self.assertEqual(exception_info["description"], "signal SIGABRT")
+        self.assertEqual(exception_info["exceptionId"], "signal")
+        exception_details = exception_info["details"]
+        self.assertRegex(exception_details["message"], "SomeReason")
+        self.assertRegex(exception_details["stackTrace"], "main.m")
diff --git a/lldb/test/API/tools/lldb-dap/exception/objc/main.m b/lldb/test/API/tools/lldb-dap/exception/objc/main.m
new file mode 100644
index 00000000000000..e8db04fb40de15
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/exception/objc/main.m
@@ -0,0 +1,8 @@
+#import <Foundation/Foundation.h>
+
+int main(int argc, char const *argv[]) {
+  @throw [[NSException alloc] initWithName:@"ThrownException"
+                                    reason:@"SomeReason"
+                                  userInfo:nil];
+  return 0;
+}
diff --git a/lldb/test/API/tools/lldb-dap/extendedStackTrace/Makefile b/lldb/test/API/tools/lldb-dap/extendedStackTrace/Makefile
new file mode 100644
index 00000000000000..e4ee1a0506c0cf
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/extendedStackTrace/Makefile
@@ -0,0 +1,5 @@
+OBJC_SOURCES := main.m
+
+USE_SYSTEM_STDLIB := 1
+
+include Makefile.rules
diff --git a/lldb/test/API/tools/lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py b/lldb/test/API/tools/lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py
new file mode 100644
index 00000000000000..efc907085b2c21
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py
@@ -0,0 +1,69 @@
+"""
+Test lldb-dap stackTrace request with an extended backtrace thread.
+"""
+
+
+import os
+
+import lldbdap_testcase
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.lldbplatformutil import *
+
+
+class TestDAP_extendedStackTrace(lldbdap_testcase.DAPTestCaseBase):
+    @skipUnlessDarwin
+    def test_stackTrace(self):
+        """
+        Tests the 'stackTrace' packet on a thread with an extended backtrace.
+        """
+        backtrace_recording_lib = findBacktraceRecordingDylib()
+        if not backtrace_recording_lib:
+            self.skipTest(
+                "Skipped because libBacktraceRecording.dylib was present on the system."
+            )
+
+        if not os.path.isfile("/usr/lib/system/introspection/libdispatch.dylib"):
+            self.skipTest(
+                "Skipped because introspection libdispatch dylib is not present."
+            )
+
+        program = self.getBuildArtifact("a.out")
+
+        self.build_and_launch(
+            program,
+            env=[
+                "DYLD_LIBRARY_PATH=/usr/lib/system/introspection",
+                "DYLD_INSERT_LIBRARIES=" + backtrace_recording_lib,
+            ],
+        )
+        source = "main.m"
+        breakpoint = line_number(source, "breakpoint 1")
+        lines = [breakpoint]
+
+        breakpoint_ids = self.set_source_breakpoints(source, lines)
+        self.assertEqual(
+            len(breakpoint_ids), len(lines), "expect correct number of breakpoints"
+        )
+
+        events = self.continue_to_next_stop()
+        print("huh", events)
+        stackFrames = self.get_stackFrames(threadId=events[0]["body"]["threadId"])
+        self.assertGreaterEqual(len(stackFrames), 3, "expect >= 3 frames")
+        self.assertEqual(stackFrames[0]["name"], "one")
+        self.assertEqual(stackFrames[1]["name"], "two")
+        self.assertEqual(stackFrames[2]["name"], "three")
+
+        stackLabels = [
+            frame
+            for frame in stackFrames
+            if frame.get("presentationHint", "") == "label"
+        ]
+        self.assertEqual(len(stackLabels), 2, "expected two label stack frames")
+        self.assertRegex(
+            stackLabels[0]["name"],
+            "Enqueued from com.apple.root.default-qos \(Thread \d\)",
+        )
+        self.assertRegex(
+            stackLabels[1]["name"], "Enqueued from com.apple.main-thread \(Thread \d\)"
+        )
diff --git a/lldb/test/API/tools/lldb-dap/extendedStackTrace/main.m b/lldb/test/API/tools/lldb-dap/extendedStackTrace/main.m
new file mode 100644
index 00000000000000..d513880236c517
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/extendedStackTrace/main.m
@@ -0,0 +1,28 @@
+#import <dispatch/dispatch.h>
+#include <stdio.h>
+
+void one() {
+  printf("one...\n"); // breakpoint 1
+}
+
+void two() {
+  printf("two...\n");
+  one();
+}
+
+void three() {
+  printf("three...\n");
+  two();
+}
+
+int main(int argc, char *argv[]) {
+  printf("main...\n");
+  // Nest from main queue > global queue > main queue.
+  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
+                 ^{
+                   dispatch_async(dispatch_get_main_queue(), ^{
+                     three();
+                   });
+                 });
+  dispatch_main();
+}
diff --git a/lldb/test/API/tools/lldb-dap/stackTrace/TestDAP_stackTrace.py b/lldb/test/API/tools/lldb-dap/stackTrace/TestDAP_stackTrace.py
index 0d7776faa4a9de..fad5419140f454 100644
--- a/lldb/test/API/tools/lldb-dap/stackTrace/TestDAP_stackTrace.py
+++ b/lldb/test/API/tools/lldb-dap/stackTrace/TestDAP_stackTrace.py
@@ -1,13 +1,11 @@
 """
-Test lldb-dap setBreakpoints request
+Test lldb-dap stackTrace request
 """
 
 
 import os
 
-import dap_server
 import lldbdap_testcase
-from lldbsuite.test import lldbutil
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
 
diff --git a/lldb/test/API/tools/lldb-dap/stackTraceMissingFunctionName/TestDAP_stackTraceMissingFunctionName.py b/lldb/test/API/tools/lldb-dap/stackTraceMissingFunctionName/TestDAP_stackTraceMissingFunctionName.py
index a04c752764fbb2..f2131d6a821217 100644
--- a/lldb/test/API/tools/lldb-dap/stackTraceMissingFunctionName/TestDAP_stackTraceMissingFunctionName.py
+++ b/lldb/test/API/tools/lldb-dap/stackTraceMissingFunctionName/TestDAP_stackTraceMissingFunctionName.py
@@ -2,13 +2,8 @@
 Test lldb-dap stack trace response
 """
 
-
-import dap_server
 from lldbsuite.test.decorators import *
-import os
-
 import lldbdap_testcase
-from lldbsuite.test import lldbtest, lldbutil
 
 
 class TestDAP_stackTraceMissingFunctionName(lldbdap_testcase.DAPTestCaseBase):
diff --git a/lldb/tools/lldb-dap/DAP.cpp b/lldb/tools/lldb-dap/DAP.cpp
index 57b93c28ce9301..1fd560f21904ab 100644
--- a/lldb/tools/lldb-dap/DAP.cpp
+++ b/lldb/tools/lldb-dap/DAP.cpp
@@ -36,7 +36,6 @@ DAP::DAP()
       focus_tid(LLDB_INVALID_THREAD_ID), stop_at_entry(false), is_attach(false),
       enable_auto_variable_summaries(false),
       enable_synthetic_child_debugging(false),
-      enable_display_extended_backtrace(false),
       restarting_process_id(LLDB_INVALID_PROCESS_ID),
       configuration_done_sent(false), waiting_for_run_in_terminal(false),
       progress_event_reporter(
diff --git a/lldb/tools/lldb-dap/DAP.h b/lldb/tools/lldb-dap/DAP.h
index 0fc77ac1e81683..c621123f18097f 100644
--- a/lldb/tools/lldb-dap/DAP.h
+++ b/lldb/tools/lldb-dap/DAP.h
@@ -181,7 +181,6 @@ struct DAP {
   bool is_attach;
   bool enable_auto_variable_summaries;
   bool enable_synthetic_child_debugging;
-  bool enable_display_extended_backtrace;
   // The process event thread normally responds to process exited events by
   // shutting down the entire adapter. When we're restarting, we keep the id of
   // the old process here so we can detect this case and keep running.
@@ -193,6 +192,7 @@ struct DAP {
   // Keep track of the last stop thread index IDs as threads won't go away
   // unless we send a "thread" event to indicate the thread exited.
   llvm::DenseSet<lldb::tid_t> thread_ids;
+  std::map<lldb::tid_t, uint32_t> thread_stack_size_cache;
   uint32_t reverse_request_seq;
   std::mutex call_mutex;
   std::map<int /* request_seq */, ResponseCallback /* reply handler */>
diff --git a/lldb/tools/lldb-dap/JSONUtils.cpp b/lldb/tools/lldb-dap/JSONUtils.cpp
index c080fd395b7288..9ea3180a7d1b67 100644
--- a/lldb/tools/lldb-dap/JSONUtils.cpp
+++ b/lldb/tools/lldb-dap/JSONUtils.cpp
@@ -1260,6 +1260,46 @@ llvm::json::Value CreateVariable(lldb::SBValue v, int64_t variablesReference,
   return llvm::json::Value(std::move(object));
 }
 
+// "ExceptionDetails": {
+//   "type": "object",
+//   "description": "Detailed information about an exception that has
+//   occurred.", "properties": {
+//     "message": {
+//       "type": "string",
+//       "description": "Message contained in the exception."
+//     },
+//     "typeName": {
+//       "type": "string",
+//       "description": "Short type name of the exception object."
+//     },
+//     "fullTypeName": {
+//       "type": "string",
+//       "description": "Fully-qualified type name of the exception object."
+//     },
+//     "evaluateName": {
+//       "type": "string",
+//       "description": "An expression that can be evaluated in the current
+//       scope to obtain the exception object."
+//     },
+//     "stackTrace": {
+//       "type": "string",
+//       "description": "Stack trace at the time the exception was thrown."
+//     },
+//     "innerException": {
+//       "type": "array",
+//       "items": {
+//         "$ref": "#/definitions/ExceptionDetails"
+//       },
+//       "description": "Details of the exception contained by this exception,
+//       if any."
+//     }
+//   }
+// },
+llvm::json::Value CreateExceptionDetails() {
+  llvm::json::Object object;
+  return llvm::json::Value(std::move(object));
+}
+
 llvm::json::Value CreateCompileUnit(lldb::SBCompileUnit unit) {
   llvm::json::Object object;
   char unit_path_arr[PATH_MAX];
diff --git a/lldb/tools/lldb-dap/JSONUtils.h b/lldb/tools/lldb-dap/JSONUtils.h
index 1515f5ba2e5f4d..88df05756a0eaa 100644
--- a/lldb/tools/lldb-dap/JSONUtils.h
+++ b/lldb/tools/lldb-dap/JSONUtils.h
@@ -467,6 +467,9 @@ llvm::json::Value CreateVariable(lldb::SBValue v, int64_t variablesReference,
                                  bool is_name_duplicated = false,
                                  std::optional<std::string> custom_name = {});
 
+/// Create a "ExceptionDetail" object for a LLDB
+llvm::json::Value CreateExceptionDetails();
+
 llvm::json::Value CreateCompileUnit(lldb::SBCompileUnit unit);
 
 /// Create a runInTerminal reverse request object
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
index 495ed0256120e8..aa34c275fad589 100644
--- a/lldb/tools/lldb-dap/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -701,8 +701,6 @@ void request_attach(const llvm::json::Object &request) {
       GetBoolean(arguments, "enableAutoVariableSummaries", false);
   g_dap.enable_synthetic_child_debugging =
       GetBoolean(arguments, "enableSyntheticChildDebugging", false);
-  g_dap.enable_display_extended_backtrace =
-      GetBoolean(arguments, "enableDisplayExtendedBacktrace", false);
   g_dap.command_escape_prefix =
       GetString(arguments, "commandEscapePrefix", "`");
   g_dap.SetFrameFormat(GetString(arguments, "customFrameFormat"));
@@ -1020,6 +1018,68 @@ void request_disconnect(const llvm::json::Object &request) {
   g_dap.disconnecting = true;
 }
 
+// "ExceptionInfoRequest": {
+//   "allOf": [ { "$ref": "#/definitions/Request" }, {
+//     "type": "object",
+//     "description": "Retrieves the details of the exception that
+//     caused this event to be raised. Clients should only call this request if
+//     the corresponding capability `supportsExceptionInfoRequest` is true.",
+//     "properties": {
+//       "command": {
+//         "type": "string",
+//         "enum": [ "exceptionInfo" ]
+//       },
+//       "arguments": {
+//         "$ref": "#/definitions/ExceptionInfoArguments"
+//       }
+//     },
+//     "required": [ "command", "arguments"  ]
+//   }]
+// },
+// "ExceptionInfoArguments": {
+//   "type": "object",
+//   "description": "Arguments for `exceptionInfo` request.",
+//   "properties": {
+//     "threadId": {
+//       "type": "integer",
+//       "description": "Thread for which exception information should be
+//       retrieved."
+//     }
+//   },
+//   "required": [ "threadId" ]
+// },
+// "ExceptionInfoResponse": {
+//   "allOf": [ { "$ref": "#/definitions/Response" }, {
+//     "type": "object",
+//     "description": "Response to `exceptionInfo` request.",
+//     "properties": {
+//       "body": {
+//         "type": "object",
+//         "properties": {
+//           "exceptionId": {
+//             "type": "string",
+//             "description": "ID of the exception that was thrown."
+//           },
+//           "description": {
+//             "type": "string",
+//             "description": "Descriptive text for the exception."
+//           },
+//           "breakMode": {
+//          "$ref": "#/definitions/ExceptionBreakMode",
+//            "description": "Mode that caused the exception notification to
+//            be raised."
+//           },
+//           "details": {
+//             "$ref": "#/definitions/ExceptionDetails",
+//            "description": "Detailed information about the exception."
+//           }
+//         },
+//         "required": [ "exceptionId", "breakMode" ]
+//       }
+//     },
+//     "required": [ "body" ]
+//   }]
+// }
 void request_exceptionInfo(const llvm::json::Object &request) {
   llvm::json::Object response;
   FillResponse(request, response);
@@ -1048,6 +1108,27 @@ void request_exceptionInfo(const llvm::json::Object &request) {
       }
     }
     body.try_emplace("breakMode", "always");
+    auto exception = thread.GetCurrentException();
+    if (exception.IsValid()) {
+      llvm::json::Object details;
+      lldb::SBStream stream;
+      if (exception.GetDescription(stream)) {
+        EmplaceSafeString(details, "message", stream.GetData());
+      }
+
+      auto exceptionBacktrace = thread.GetCurrentExceptionBacktrace();
+      if (exceptionBacktrace.IsValid()) {
+        lldb::SBStream stream;
+        exceptionBacktrace.GetDescription(stream);
+        for (uint32_t i = 0; i < exceptionBacktrace.GetNumFrames(); i++) {
+          lldb::SBFrame frame = exceptionBacktrace.GetFrameAtIndex(i);
+          frame.GetDescription(stream);
+        }
+        EmplaceSafeString(details, "stackTrace", stream.GetData());
+      }
+
+      body.try_emplace("details", std::move(details));
+    }
     // auto excInfoCount = thread.GetStopReasonDataCount();
     // for (auto i=0; i<excInfoCount; ++i) {
     //   uint64_t exc_data = thread.GetStopReasonDataAtIndex(i);
@@ -1927,8 +2008,6 @@ void request_launch(const llvm::json::Object &request) {
       GetBoolean(arguments, "enableAutoVariableSummaries", false);
   g_dap.enable_synthetic_child_debugging =
       GetBoolean(arguments, "enableSyntheticChildDebugging", false);
-  g_dap.enable_display_extended_backtrace =
-      GetBoolean(arguments, "enableDisplayExtendedBacktrace", false);
   g_dap.command_escape_prefix =
       GetString(arguments, "commandEscapePrefix", "`");
   g_dap.SetFrameFormat(GetString(arguments, "customFrameFormat"));
@@ -3064,7 +3143,9 @@ void request_source(const llvm::json::Object &request) {
 //     },
 //     "format": {
 //       "$ref": "#/definitions/StackFrameFormat",
-//       "description": "Specifies details on how to format the stack frames."
+//       "description": "Specifies details on how to format the stack frames.
+//       The attribute is only honored by a debug adapter if the corresponding
+//       capability `supportsValueFormattingOptions` is true."
 //     }
 //  },
 //   "required": [ "threadId" ]
@@ -3072,7 +3153,7 @@ void request_source(const llvm::json::Object &request) {
 // "StackTraceResponse": {
 //   "allOf": [ { "$ref": "#/definitions/Response" }, {
 //     "type": "object",
-//     "description": "Response to 'stackTrace' request.",
+//     "description": "Response to `stackTrace` request.",
 //     "properties": {
 //       "body": {
 //         "type": "object",
@@ -3088,7 +3169,13 @@ void request_source(const llvm::json::Object &request) {
 //           },
 //           "totalFrames": {
 //             "type": "integer",
-//             "description": "The total number of frames available."
+//             "description": "The total number of frames available in the
+//             stack. If omitted or if `totalFrames` is larger than the
+//             available frames, a client is expected to request frames until
+//             a request returns less frames than requested (which indicates
+//             the end of the stack). Returning monotonically increasing
+//             `totalFrames` values for subsequent requests can be used to
+//             enforce paging in the client."
 //           }
 //         },
 //         "required": [ "stackFrames" ]
@@ -3106,80 +3193,105 @@ void request_stackTrace(const llvm::json::Object &request) {
   llvm::json::Array stackFrames;
   llvm::json::Object body;
 
+  // Threads stacks may contain runtime specific extended backtraces, when
+  // constructing a stack trace first report the full thread stack trace then
+  // perform a breadth first traversal of any extended backtrace frames.
+  //
+  // For example:
+  //
+  // Thread (id=th0) stack=[s0, s1, s2, s3]
+  //   \ Extended backtrace "libdispatch" Thread (id=th1) stack=[s0, s1]
+  //     \ Extended backtrace "libdispatch" Thread (id=th2) stack=[s0, s1]
+  //   \ Extended backtrace "Application Specific Backtrace" Thread (id=th3)
+  //   stack=[s0, s1, s2]
+  //
+  // Which will flatten into:
+  //
+  //  0. th0->s0
+  //  1. th0->s1
+  //  2. th0->s2
+  //  3. th0->s3
+  //  4. label - Enqueued from th1
+  //  5. th1->s0
+  //  6. th1->s1
+  //  7. label - Enqueued from th2
+  //  8. th2->s0
+  //  9. th2->s1
+  // 10. label - Application Specific Backtrace
+  // 11. th3->s0
+  // 12. th3->s1
+  // 13. th3->s2
+
   if (thread.IsValid()) {
     const auto startFrame = GetUnsigned(arguments, "startFrame", 0);
     const auto levels = GetUnsigned(arguments, "levels", 0);
     const auto endFrame = (levels == 0) ? INT64_MAX : (startFrame + levels);
-    auto totalFrames = thread.GetNumFrames();
-
-    // This will always return an invalid thread when
-    // libBacktraceRecording.dylib is not loaded or if there is no extended
-    // backtrace.
-    lldb::SBThread queue_backtrace_thread;
-    if (g_dap.enable_display_extended_backtrace)
-      queue_backtrace_thread = thread.GetExtendedBacktraceThread("libdispatch");
-    if (queue_backtrace_thread.IsValid()) {
-      // One extra frame as a label to mark the enqueued thread.
-      totalFrames += queue_backtrace_thread.GetNumFrames() + 1;
-    }
+    bool done = false;
+    int64_t offset = 0;
+    lldb::SBProcess process = thread.GetProcess();
+    llvm::SmallVector<lldb::SBThread> threadCluster{{thread}};
+
+    for (uint32_t i = startFrame; i < endFrame && !threadCluster.empty(); ++i) {
+      lldb::SBThread current = threadCluster.front();
+      lldb::SBFrame frame = current.GetFrameAtIndex(i - offset);
+
+      // If we don't have a valid frame, check if we have any extended frames to
+      // report.
+      // *NOTE*: Threads can be chained across mutliple backtraces, so we
+      // need to keep track of each backtrace we've traversed fully in the
+      // offset.
+      while (!frame.IsValid() && current.IsValid() && !threadCluster.empty()) {
+        offset += current.GetNumFrames() +
+                  1 /* one extra frame for a label between threads*/;
+        threadCluster.pop_back();
+
+        // Check for any extended backtraces.
+        for (uint32_t i = 0; i < process.GetNumExtendedBacktraceTypes(); i++) {
+          lldb::SBThread backtrace = current.GetExtendedBacktraceThread(
+              process.GetExtendedBacktraceTypeAtIndex(i));
+          if (backtrace.IsValid()) {
+            threadCluster.emplace_back(backtrace);
+          }
+        }
 
-    // This will always return an invalid thread when there is no exception in
-    // the current thread.
-    lldb::SBThread exception_backtrace_thread;
-    if (g_dap.enable_display_extended_backtrace)
-      exception_backtrace_thread = thread.GetCurrentExceptionBacktrace();
+        if (threadCluster.empty())
+          break;
 
-    if (exception_backtrace_thread.IsValid()) {
-      // One extra frame as a label to mark the exception thread.
-      totalFrames += exception_backtrace_thread.GetNumFrames() + 1;
-    }
+        current = threadCluster.front();
+        frame = current.GetFrameAtIndex(0);
+      }
 
-    for (uint32_t i = startFrame; i < endFrame; ++i) {
-      lldb::SBFrame frame;
-      std::string prefix;
-      if (i < thread.GetNumFrames()) {
-        frame = thread.GetFrameAtIndex(i);
-      } else if (queue_backtrace_thread.IsValid() &&
-                 i < (thread.GetNumFrames() +
-                      queue_backtrace_thread.GetNumFrames() + 1)) {
-        if (i == thread.GetNumFrames()) {
-          const uint32_t thread_idx =
-              queue_backtrace_thread.GetExtendedBacktraceOriginatingIndexID();
-          const char *queue_name = queue_backtrace_thread.GetQueueName();
-          auto name = llvm::formatv("Enqueued from {0} (Thread {1})",
-                                    queue_name, thread_idx);
-          stackFrames.emplace_back(
-              llvm::json::Object{{"id", thread.GetThreadID() + 1},
-                                 {"name", name},
-                                 {"presentationHint", "label"}});
-          continue;
-        }
-        frame = queue_backtrace_thread.GetFrameAtIndex(
-            i - thread.GetNumFrames() - 1);
-      } else if (exception_backtrace_thread.IsValid()) {
-        if (i == thread.GetNumFrames() +
-                     (queue_backtrace_thread.IsValid()
-                          ? queue_backtrace_thread.GetNumFrames() + 1
-                          : 0)) {
-          stackFrames.emplace_back(
-              llvm::json::Object{{"id", thread.GetThreadID() + 2},
-                                 {"name", "Original Exception Backtrace"},
-                                 {"presentationHint", "label"}});
-          continue;
-        }
+      // If we're out of extended backtraces, no more frames to load.
+      if (!frame.IsValid() && threadCluster.empty()) {
+        done = true;
+        break;
+      }
 
-        frame = exception_backtrace_thread.GetFrameAtIndex(
-            i - thread.GetNumFrames() -
-            (queue_backtrace_thread.IsValid()
-                 ? queue_backtrace_thread.GetNumFrames() + 1
-                 : 0));
+      // Between the thread and extended backtrace add a label.
+      if (offset != 0 && (i - offset) == 0) {
+        const uint32_t thread_idx =
+            current.GetExtendedBacktraceOriginatingIndexID();
+        const char *queue_name = current.GetQueueName();
+        std::string name;
+        if (queue_name != nullptr) {
+          name = llvm::formatv("Enqueued from {0} (Thread {1})", queue_name,
+                               thread_idx);
+        } else {
+          name = llvm::formatv("Thread {0}", thread_idx);
+        }
+        stackFrames.emplace_back(
+            llvm::json::Object{{"id", thread.GetThreadID() + 1},
+                               {"name", name},
+                               {"presentationHint", "label"}});
+      } else {
+        stackFrames.emplace_back(CreateStackFrame(frame));
       }
-      if (!frame.IsValid())
-        break;
-      stackFrames.emplace_back(CreateStackFrame(frame));
     }
 
-    body.try_emplace("totalFrames", totalFrames);
+    // If we loaded all the frames, set the total frame to the current total,
+    // otherwise use the totalFrames to indiciate more data is available.
+    body.try_emplace("totalFrames",
+                     startFrame + stackFrames.size() + (done ? 0 : 1));
   }
   body.try_emplace("stackFrames", std::move(stackFrames));
   response.try_emplace("body", std::move(body));
@@ -3485,7 +3597,6 @@ void request_stepOut(const llvm::json::Object &request) {
 //   }]
 // }
 void request_threads(const llvm::json::Object &request) {
-
   lldb::SBProcess process = g_dap.target.GetProcess();
   llvm::json::Object response;
   FillResponse(request, response);

>From f7e658f0e7960be99279e42fd23a7e4d76151eb9 Mon Sep 17 00:00:00 2001
From: John Harrison <harjohn at google.com>
Date: Fri, 23 Aug 2024 16:23:30 -0700
Subject: [PATCH 2/5] Move the ExceptionDetails type info closer to
 request_exceptionInfo

---
 lldb/tools/lldb-dap/JSONUtils.cpp | 40 -------------------------------
 lldb/tools/lldb-dap/JSONUtils.h   |  3 ---
 lldb/tools/lldb-dap/lldb-dap.cpp  | 35 +++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 43 deletions(-)

diff --git a/lldb/tools/lldb-dap/JSONUtils.cpp b/lldb/tools/lldb-dap/JSONUtils.cpp
index 9ea3180a7d1b67..c080fd395b7288 100644
--- a/lldb/tools/lldb-dap/JSONUtils.cpp
+++ b/lldb/tools/lldb-dap/JSONUtils.cpp
@@ -1260,46 +1260,6 @@ llvm::json::Value CreateVariable(lldb::SBValue v, int64_t variablesReference,
   return llvm::json::Value(std::move(object));
 }
 
-// "ExceptionDetails": {
-//   "type": "object",
-//   "description": "Detailed information about an exception that has
-//   occurred.", "properties": {
-//     "message": {
-//       "type": "string",
-//       "description": "Message contained in the exception."
-//     },
-//     "typeName": {
-//       "type": "string",
-//       "description": "Short type name of the exception object."
-//     },
-//     "fullTypeName": {
-//       "type": "string",
-//       "description": "Fully-qualified type name of the exception object."
-//     },
-//     "evaluateName": {
-//       "type": "string",
-//       "description": "An expression that can be evaluated in the current
-//       scope to obtain the exception object."
-//     },
-//     "stackTrace": {
-//       "type": "string",
-//       "description": "Stack trace at the time the exception was thrown."
-//     },
-//     "innerException": {
-//       "type": "array",
-//       "items": {
-//         "$ref": "#/definitions/ExceptionDetails"
-//       },
-//       "description": "Details of the exception contained by this exception,
-//       if any."
-//     }
-//   }
-// },
-llvm::json::Value CreateExceptionDetails() {
-  llvm::json::Object object;
-  return llvm::json::Value(std::move(object));
-}
-
 llvm::json::Value CreateCompileUnit(lldb::SBCompileUnit unit) {
   llvm::json::Object object;
   char unit_path_arr[PATH_MAX];
diff --git a/lldb/tools/lldb-dap/JSONUtils.h b/lldb/tools/lldb-dap/JSONUtils.h
index 88df05756a0eaa..1515f5ba2e5f4d 100644
--- a/lldb/tools/lldb-dap/JSONUtils.h
+++ b/lldb/tools/lldb-dap/JSONUtils.h
@@ -467,9 +467,6 @@ llvm::json::Value CreateVariable(lldb::SBValue v, int64_t variablesReference,
                                  bool is_name_duplicated = false,
                                  std::optional<std::string> custom_name = {});
 
-/// Create a "ExceptionDetail" object for a LLDB
-llvm::json::Value CreateExceptionDetails();
-
 llvm::json::Value CreateCompileUnit(lldb::SBCompileUnit unit);
 
 /// Create a runInTerminal reverse request object
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
index aa34c275fad589..f8e22f1a791802 100644
--- a/lldb/tools/lldb-dap/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -1080,6 +1080,41 @@ void request_disconnect(const llvm::json::Object &request) {
 //     "required": [ "body" ]
 //   }]
 // }
+// "ExceptionDetails": {
+//   "type": "object",
+//   "description": "Detailed information about an exception that has
+//   occurred.", "properties": {
+//     "message": {
+//       "type": "string",
+//       "description": "Message contained in the exception."
+//     },
+//     "typeName": {
+//       "type": "string",
+//       "description": "Short type name of the exception object."
+//     },
+//     "fullTypeName": {
+//       "type": "string",
+//       "description": "Fully-qualified type name of the exception object."
+//     },
+//     "evaluateName": {
+//       "type": "string",
+//       "description": "An expression that can be evaluated in the current
+//       scope to obtain the exception object."
+//     },
+//     "stackTrace": {
+//       "type": "string",
+//       "description": "Stack trace at the time the exception was thrown."
+//     },
+//     "innerException": {
+//       "type": "array",
+//       "items": {
+//         "$ref": "#/definitions/ExceptionDetails"
+//       },
+//       "description": "Details of the exception contained by this exception,
+//       if any."
+//     }
+//   }
+// },
 void request_exceptionInfo(const llvm::json::Object &request) {
   llvm::json::Object response;
   FillResponse(request, response);

>From aacdd80d6e5f2a109e4de0f64bf3eab6edad6896 Mon Sep 17 00:00:00 2001
From: John Harrison <harjohn at google.com>
Date: Fri, 23 Aug 2024 16:25:26 -0700
Subject: [PATCH 3/5] Cleaning up unused variables.

---
 lldb/tools/lldb-dap/DAP.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lldb/tools/lldb-dap/DAP.h b/lldb/tools/lldb-dap/DAP.h
index c621123f18097f..27ea6c7ff8423f 100644
--- a/lldb/tools/lldb-dap/DAP.h
+++ b/lldb/tools/lldb-dap/DAP.h
@@ -192,7 +192,6 @@ struct DAP {
   // Keep track of the last stop thread index IDs as threads won't go away
   // unless we send a "thread" event to indicate the thread exited.
   llvm::DenseSet<lldb::tid_t> thread_ids;
-  std::map<lldb::tid_t, uint32_t> thread_stack_size_cache;
   uint32_t reverse_request_seq;
   std::mutex call_mutex;
   std::map<int /* request_seq */, ResponseCallback /* reply handler */>

>From 029a174b20ab538a04802d942b0bce1b2818c376 Mon Sep 17 00:00:00 2001
From: John Harrison <harjohn at google.com>
Date: Fri, 23 Aug 2024 16:35:02 -0700
Subject: [PATCH 4/5] Cleanup debug logs

---
 .../lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lldb/test/API/tools/lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py b/lldb/test/API/tools/lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py
index efc907085b2c21..ec62151c318acc 100644
--- a/lldb/test/API/tools/lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py
+++ b/lldb/test/API/tools/lldb-dap/extendedStackTrace/TestDAP_extendedStackTrace.py
@@ -47,7 +47,7 @@ def test_stackTrace(self):
         )
 
         events = self.continue_to_next_stop()
-        print("huh", events)
+
         stackFrames = self.get_stackFrames(threadId=events[0]["body"]["threadId"])
         self.assertGreaterEqual(len(stackFrames), 3, "expect >= 3 frames")
         self.assertEqual(stackFrames[0]["name"], "one")

>From 7960402faaeabeba610cc56cba04638e355563c8 Mon Sep 17 00:00:00 2001
From: John Harrison <harjohn at google.com>
Date: Wed, 28 Aug 2024 14:25:57 -0700
Subject: [PATCH 5/5] Adjusting the lldb-dap stackTrace to use a
 StackPageSize=20 const instead of only a +1.

This helps improve pagination of deep stack traces.
---
 .../lldb-dap/stackTrace/TestDAP_stackTrace.py | 19 +++++++++++++++----
 .../test/API/tools/lldb-dap/stackTrace/main.c |  2 +-
 lldb/tools/lldb-dap/lldb-dap.cpp              |  7 +++++--
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/lldb/test/API/tools/lldb-dap/stackTrace/TestDAP_stackTrace.py b/lldb/test/API/tools/lldb-dap/stackTrace/TestDAP_stackTrace.py
index fad5419140f454..da9332eea3e0e0 100644
--- a/lldb/test/API/tools/lldb-dap/stackTrace/TestDAP_stackTrace.py
+++ b/lldb/test/API/tools/lldb-dap/stackTrace/TestDAP_stackTrace.py
@@ -15,11 +15,14 @@ class TestDAP_stackTrace(lldbdap_testcase.DAPTestCaseBase):
     source_key_path = ["source", "path"]
     line_key_path = ["line"]
 
+    # stackTrace additioanl frames for paginated traces
+    page_size = 20
+
     def verify_stackFrames(self, start_idx, stackFrames):
         frame_idx = start_idx
         for stackFrame in stackFrames:
             # Don't care about frame above main
-            if frame_idx > 20:
+            if frame_idx > 40:
                 return
             self.verify_stackFrame(frame_idx, stackFrame)
             frame_idx += 1
@@ -31,7 +34,7 @@ def verify_stackFrame(self, frame_idx, stackFrame):
         if frame_idx == 0:
             expected_line = self.recurse_end
             expected_name = "recurse"
-        elif frame_idx < 20:
+        elif frame_idx < 40:
             expected_line = self.recurse_call
             expected_name = "recurse"
         else:
@@ -81,10 +84,18 @@ def test_stackTrace(self):
         (stackFrames, totalFrames) = self.get_stackFrames_and_totalFramesCount()
         frameCount = len(stackFrames)
         self.assertGreaterEqual(
-            frameCount, 20, "verify we get at least 20 frames for all frames"
+            frameCount, 40, "verify we get at least 40 frames for all frames"
+        )
+        self.assertEqual(
+            totalFrames, frameCount, "verify total frames returns a speculative page size"
         )
+        self.verify_stackFrames(startFrame, stackFrames)
+
+        # Verify totalFrames contains a speculative page size of additional frames with startFrame = 0 and levels = 0
+        (stackFrames, totalFrames) = self.get_stackFrames_and_totalFramesCount(startFrame=0, levels=10)
+        self.assertEqual(len(stackFrames), 10, "verify we get levels=10 frames")
         self.assertEqual(
-            totalFrames, frameCount, "verify we get correct value for totalFrames count"
+            totalFrames, len(stackFrames) + self.page_size, "verify total frames returns a speculative page size"
         )
         self.verify_stackFrames(startFrame, stackFrames)
 
diff --git a/lldb/test/API/tools/lldb-dap/stackTrace/main.c b/lldb/test/API/tools/lldb-dap/stackTrace/main.c
index 862473a3e6ac8c..25d81be08e7782 100644
--- a/lldb/test/API/tools/lldb-dap/stackTrace/main.c
+++ b/lldb/test/API/tools/lldb-dap/stackTrace/main.c
@@ -8,6 +8,6 @@ int recurse(int x) {
 }
 
 int main(int argc, char const *argv[]) {
-  recurse(20); // recurse invocation
+  recurse(40); // recurse invocation
   return 0;
 }
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
index f8e22f1a791802..b5ac9b32361ab8 100644
--- a/lldb/tools/lldb-dap/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -112,6 +112,9 @@ typedef void (*RequestCallback)(const llvm::json::Object &command);
 
 enum LaunchMethod { Launch, Attach, AttachForSuspendedLaunch };
 
+/// Page size used for reporting addtional frames in the 'stackTrace' request.
+constexpr int StackPageSize = 20;
+
 /// Prints a welcome message on the editor if the preprocessor variable
 /// LLDB_DAP_WELCOME_MESSAGE is defined.
 static void PrintWelcomeMessage() {
@@ -3324,9 +3327,9 @@ void request_stackTrace(const llvm::json::Object &request) {
     }
 
     // If we loaded all the frames, set the total frame to the current total,
-    // otherwise use the totalFrames to indiciate more data is available.
+    // otherwise use the totalFrames to indicate more data is available.
     body.try_emplace("totalFrames",
-                     startFrame + stackFrames.size() + (done ? 0 : 1));
+                     startFrame + stackFrames.size() + (done ? 0 : StackPageSize));
   }
   body.try_emplace("stackFrames", std::move(stackFrames));
   response.try_emplace("body", std::move(body));



More information about the lldb-commits mailing list