[LLDB] Add SBProgress so Python scripts can also report progress (#119052)

Recently I've been working on a lot of internal Python tooling, and in
certain cases I want to report async to the script over DAP. Progress.h
already handles this, so I've exposed Progress via the SB API so Python
scripts can also update progress objects.

I actually have no idea how to test this, so I just wrote a [toy command
to test
it](https://gist.github.com/Jlalond/48d85e75a91f7a137e3142e6a13d0947)


![image](https://github.com/user-attachments/assets/7317cbb8-9145-4fdb-bacf-9864bf50c467)

I also copied the first section of the extensive Progress.h class
documentation to the docstrings.

lldb/bindings/headers.swig

@@ -52,6 +52,7 @@
 #include "lldb/API/SBProcess.h"
 #include "lldb/API/SBProcessInfo.h"
 #include "lldb/API/SBProcessInfoList.h"
+#include "lldb/API/SBProgress.h"
 #include "lldb/API/SBQueue.h"
 #include "lldb/API/SBQueueItem.h"
 #include "lldb/API/SBReproducer.h"

lldb/bindings/interface/SBProgressDocstrings.i

@@ -0,0 +1,14 @@
+%feature("docstring",
+"A Progress indicator helper class.
+
+Any potentially long running sections of code in LLDB should report
+progress so that clients are aware of delays that might appear during
+debugging. Delays commonly include indexing debug information, parsing
+symbol tables for object files, downloading symbols from remote
+repositories, and many more things.
+
+The Progress class helps make sure that progress is correctly reported
+and will always send an initial progress update, updates when
+Progress::Increment() is called, and also will make sure that a progress
+completed update is reported even if the user doesn't explicitly cause one
+to be sent.") lldb::SBProgress;

lldb/bindings/interfaces.swig

@@ -54,6 +54,7 @@
 %include "./interface/SBPlatformDocstrings.i"
 %include "./interface/SBProcessDocstrings.i"
 %include "./interface/SBProcessInfoDocstrings.i"
+%include "./interface/SBProgressDocstrings.i"
 %include "./interface/SBQueueDocstrings.i"
 %include "./interface/SBQueueItemDocstrings.i"
 %include "./interface/SBReproducerDocstrings.i"
@@ -133,6 +134,7 @@
 %include "lldb/API/SBProcess.h"
 %include "lldb/API/SBProcessInfo.h"
 %include "lldb/API/SBProcessInfoList.h"
+%include "lldb/API/SBProgress.h"
 %include "lldb/API/SBQueue.h"
 %include "lldb/API/SBQueueItem.h"
 %include "lldb/API/SBReproducer.h"

lldb/include/lldb/API/SBDebugger.h

@@ -203,7 +203,7 @@ public:
   lldb::SBCommandInterpreter GetCommandInterpreter();
 
   void HandleCommand(const char *command);
-  
+
   void RequestInterrupt();
   void CancelInterruptRequest();
   bool InterruptRequested();
@@ -517,6 +517,7 @@ private:
   friend class SBPlatform;
   friend class SBTarget;
   friend class SBTrace;
+  friend class SBProgress;
 
   lldb::SBTarget FindTargetWithLLDBProcess(const lldb::ProcessSP &processSP);
 

lldb/include/lldb/API/SBProgress.h

@@ -0,0 +1,66 @@
+//===-- SBProgress.h --------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_API_SBPROGRESS_H
+#define LLDB_API_SBPROGRESS_H
+
+#include "lldb/API/SBDebugger.h"
+#include "lldb/API/SBDefines.h"
+
+namespace lldb {
+
+/// A Progress indicator helper class.
+///
+/// Any potentially long running sections of code in LLDB should report
+/// progress so that clients are aware of delays that might appear during
+/// debugging. Delays commonly include indexing debug information, parsing
+/// symbol tables for object files, downloading symbols from remote
+/// repositories, and many more things.
+///
+/// The Progress class helps make sure that progress is correctly reported
+/// and will always send an initial progress update, updates when
+/// Progress::Increment() is called, and also will make sure that a progress
+/// completed update is reported even if the user doesn't explicitly cause one
+/// to be sent.
+class LLDB_API SBProgress {
+public:
+  /// Construct a progress object with a title, details and a given debugger.
+  /// \param title
+  ///   The title of the progress object.
+  /// \param details
+  ///   The details of the progress object.
+  /// \param debugger
+  ///   The debugger for this progress object to report to.
+  SBProgress(const char *title, const char *details, SBDebugger &debugger);
+
+  /// Construct a progress object with a title, details, the total units of work
+  /// to be done, and a given debugger.
+  /// \param title
+  ///   The title of the progress object.
+  /// \param details
+  ///   The details of the progress object.
+  /// \param total_units
+  ///   The total number of units of work to be done.
+  /// \param debugger
+  ///   The debugger for this progress object to report to.
+  SBProgress(const char *title, const char *details, uint64_t total_units,
+             SBDebugger &debugger);
+
+  ~SBProgress();
+
+  void Increment(uint64_t amount, const char *description = nullptr);
+
+protected:
+  lldb_private::Progress &ref() const;
+
+private:
+  std::unique_ptr<lldb_private::Progress> m_opaque_up;
+}; // SBProgress
+} // namespace lldb
+
+#endif // LLDB_API_SBPROGRESS_H

lldb/include/lldb/lldb-forward.h

@@ -233,6 +233,7 @@ class Symtab;
 class SyntheticChildren;
 class SyntheticChildrenFrontEnd;
 class SystemRuntime;
+class Progress;
 class Target;
 class TargetList;
 class TargetProperties;

lldb/source/API/CMakeLists.txt

@@ -83,6 +83,7 @@ add_lldb_library(liblldb SHARED ${option_framework}
   SBModule.cpp
   SBModuleSpec.cpp
   SBPlatform.cpp
+  SBProgress.cpp
   SBProcess.cpp
   SBProcessInfo.cpp
   SBProcessInfoList.cpp

lldb/source/API/SBProgress.cpp

@@ -0,0 +1,43 @@
+//===-- SBProgress.cpp --------------------------------------------------*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/API/SBProgress.h"
+#include "lldb/Core/Progress.h"
+#include "lldb/Utility/Instrumentation.h"
+
+using namespace lldb;
+
+SBProgress::SBProgress(const char *title, const char *details,
+                       SBDebugger &debugger) {
+  LLDB_INSTRUMENT_VA(this, title, details, debugger);
+
+  m_opaque_up = std::make_unique<lldb_private::Progress>(
+      title, details, /*total=*/std::nullopt, debugger.get(),
+      /*minimum_report_time=*/std::nullopt,
+      lldb_private::Progress::Origin::eExternal);
+}
+
+SBProgress::SBProgress(const char *title, const char *details,
+                       uint64_t total_units, SBDebugger &debugger) {
+  LLDB_INSTRUMENT_VA(this, title, details, total_units, debugger);
+
+  m_opaque_up = std::make_unique<lldb_private::Progress>(
+      title, details, total_units, debugger.get(),
+      /*minimum_report_time=*/std::nullopt,
+      lldb_private::Progress::Origin::eExternal);
+}
+
+SBProgress::~SBProgress() = default;
+
+void SBProgress::Increment(uint64_t amount, const char *description) {
+  LLDB_INSTRUMENT_VA(amount, description);
+
+  m_opaque_up->Increment(amount, description);
+}
+
+lldb_private::Progress &SBProgress::ref() const { return *m_opaque_up; }

lldb/source/Core/Debugger.cpp

@@ -1952,7 +1952,8 @@ lldb::thread_result_t Debugger::DefaultEventHandler() {
   listener_sp->StartListeningForEvents(
       &m_broadcaster, lldb::eBroadcastBitProgress | lldb::eBroadcastBitWarning |
                           lldb::eBroadcastBitError |
-                          lldb::eBroadcastSymbolChange);
+                          lldb::eBroadcastSymbolChange |
+                          lldb::eBroadcastBitExternalProgress);
 
   // Let the thread that spawned us know that we have started up and that we
   // are now listening to all required events so no events get missed

lldb/test/API/python_api/sbprogress/TestSBProgress.py

@@ -0,0 +1,35 @@
+"""Test the SBProgress API."""
+
+import lldb
+from lldbsuite.test.lldbtest import *
+
+
+class SBProgressTestCase(TestBase):
+    def test_with_external_bit_set(self):
+        """Test SBProgress events are listened to when the external bit is set."""
+
+        progress = lldb.SBProgress("Test SBProgress", "Test progress", self.dbg)
+        listener = lldb.SBListener("Test listener")
+        broadcaster = self.dbg.GetBroadcaster()
+        broadcaster.AddListener(listener, lldb.eBroadcastBitExternalProgress)
+        event = lldb.SBEvent()
+
+        expected_string = "Test progress first increment"
+        progress.Increment(1, expected_string)
+        self.assertTrue(listener.PeekAtNextEvent(event))
+        stream = lldb.SBStream()
+        event.GetDescription(stream)
+        self.assertIn(expected_string, stream.GetData())
+
+    def test_without_external_bit_set(self):
+        """Test SBProgress events are not listened to on the internal progress bit."""
+
+        progress = lldb.SBProgress("Test SBProgress", "Test progress", self.dbg)
+        listener = lldb.SBListener("Test listener")
+        broadcaster = self.dbg.GetBroadcaster()
+        broadcaster.AddListener(listener, lldb.eBroadcastBitProgress)
+        event = lldb.SBEvent()
+
+        expected_string = "Test progress first increment"
+        progress.Increment(1, expected_string)
+        self.assertFalse(listener.PeekAtNextEvent(event))