[lldb/Plugins] Add ScriptedProcess Process Plugin

This patch introduces Scripted Processes to lldb.

The goal, here, is to be able to attach in the debugger to fake processes
that are backed by script files (in Python, Lua, Swift, etc ...) and
inspect them statically.

Scripted Processes can be used in cooperative multithreading environments
like the XNU Kernel or other real-time operating systems, but it can
also help us improve the debugger testing infrastructure by writting
synthetic tests that simulates hard-to-reproduce process/thread states.

Although ScriptedProcess is not feature-complete at the moment, it has
basic execution capabilities and will improve in the following patches.

rdar://65508855

Differential Revision: https://reviews.llvm.org/D95713

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
GitOrigin-RevId: b09d44b6ae0901865a0d4b2a0cf797c3cd34eeeb
diff --git a/bindings/python/CMakeLists.txt b/bindings/python/CMakeLists.txt
index 9422ee0..b5c75f5 100644
--- a/bindings/python/CMakeLists.txt
+++ b/bindings/python/CMakeLists.txt
@@ -111,6 +111,13 @@
     FILES
     "${LLDB_SOURCE_DIR}/examples/python/scripted_process/scripted_process.py")
 
+  create_python_package(
+    ${swig_target}
+    ${lldb_python_target_dir}
+    "plugins"
+    FILES
+    "${LLDB_SOURCE_DIR}/examples/python/scripted_process/scripted_process.py")
+
   if(APPLE)
     create_python_package(
       ${swig_target}
diff --git a/include/lldb/Target/Process.h b/include/lldb/Target/Process.h
index fbdb506..127f03f 100644
--- a/include/lldb/Target/Process.h
+++ b/include/lldb/Target/Process.h
@@ -2561,8 +2561,6 @@
   virtual size_t DoReadMemory(lldb::addr_t vm_addr, void *buf, size_t size,
                               Status &error) = 0;
 
-  void SetState(lldb::EventSP &event_sp);
-
   lldb::StateType GetPrivateState();
 
   /// The "private" side of resuming a process.  This doesn't alter the state
diff --git a/source/Plugins/Process/CMakeLists.txt b/source/Plugins/Process/CMakeLists.txt
index fdeb211..befa743 100644
--- a/source/Plugins/Process/CMakeLists.txt
+++ b/source/Plugins/Process/CMakeLists.txt
@@ -12,6 +12,9 @@
 elseif (CMAKE_SYSTEM_NAME MATCHES "Darwin")
   add_subdirectory(MacOSX-Kernel)
 endif()
+if (LLDB_ENABLE_PYTHON)
+  add_subdirectory(scripted)
+endif()
 add_subdirectory(gdb-remote)
 add_subdirectory(Utility)
 add_subdirectory(elf-core)
diff --git a/source/Plugins/Process/scripted/CMakeLists.txt b/source/Plugins/Process/scripted/CMakeLists.txt
new file mode 100644
index 0000000..e2cfd05
--- /dev/null
+++ b/source/Plugins/Process/scripted/CMakeLists.txt
@@ -0,0 +1,13 @@
+add_lldb_library(lldbPluginScriptedProcess PLUGIN
+  ScriptedProcess.cpp
+
+  LINK_LIBS
+    lldbCore
+    lldbTarget
+    lldbUtility
+    lldbPluginProcessUtility
+  LINK_COMPONENTS
+    BinaryFormat
+    Object
+    Support
+  )
diff --git a/source/Plugins/Process/scripted/ScriptedProcess.cpp b/source/Plugins/Process/scripted/ScriptedProcess.cpp
new file mode 100644
index 0000000..20fbef5
--- /dev/null
+++ b/source/Plugins/Process/scripted/ScriptedProcess.cpp
@@ -0,0 +1,244 @@
+//===-- ScriptedProcess.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 "ScriptedProcess.h"
+
+#include "lldb/Core/Debugger.h"
+#include "lldb/Core/Module.h"
+#include "lldb/Core/PluginManager.h"
+
+#include "lldb/Host/OptionParser.h"
+
+#include "lldb/Interpreter/OptionArgParser.h"
+#include "lldb/Interpreter/OptionGroupBoolean.h"
+#include "lldb/Interpreter/ScriptInterpreter.h"
+#include "lldb/Target/MemoryRegionInfo.h"
+
+LLDB_PLUGIN_DEFINE(ScriptedProcess)
+
+using namespace lldb;
+using namespace lldb_private;
+
+ConstString ScriptedProcess::GetPluginNameStatic() {
+  static ConstString g_name("ScriptedProcess");
+  return g_name;
+}
+
+const char *ScriptedProcess::GetPluginDescriptionStatic() {
+  return "Scripted Process plug-in.";
+}
+
+lldb::ProcessSP ScriptedProcess::CreateInstance(lldb::TargetSP target_sp,
+                                                lldb::ListenerSP listener_sp,
+                                                const FileSpec *file,
+                                                bool can_connect) {
+  ScriptedProcess::LaunchInfo launch_info(target_sp->GetProcessLaunchInfo());
+
+  auto process_sp =
+      std::make_shared<ScriptedProcess>(target_sp, listener_sp, launch_info);
+
+  if (!process_sp || !process_sp->m_script_object_sp ||
+      !process_sp->m_script_object_sp->IsValid())
+    return nullptr;
+
+  return process_sp;
+}
+
+bool ScriptedProcess::CanDebug(lldb::TargetSP target_sp,
+                               bool plugin_specified_by_name) {
+  return true;
+}
+
+ScriptedProcess::ScriptedProcess(lldb::TargetSP target_sp,
+                                 lldb::ListenerSP listener_sp,
+                                 const ScriptedProcess::LaunchInfo &launch_info)
+    : Process(target_sp, listener_sp), m_launch_info(launch_info) {
+  if (!target_sp)
+    return;
+
+  m_interpreter = target_sp->GetDebugger().GetScriptInterpreter();
+
+  if (!m_interpreter)
+    return;
+
+  StructuredData::ObjectSP object_sp = GetInterface().CreatePluginObject(
+      m_launch_info.GetClassName().c_str(), target_sp,
+      m_launch_info.GetDictionarySP());
+
+  if (object_sp && object_sp->IsValid())
+    m_script_object_sp = object_sp;
+}
+
+ScriptedProcess::~ScriptedProcess() {
+  Clear();
+  // We need to call finalize on the process before destroying ourselves to
+  // make sure all of the broadcaster cleanup goes as planned. If we destruct
+  // this class, then Process::~Process() might have problems trying to fully
+  // destroy the broadcaster.
+  Finalize();
+}
+
+void ScriptedProcess::Initialize() {
+  static llvm::once_flag g_once_flag;
+
+  llvm::call_once(g_once_flag, []() {
+    PluginManager::RegisterPlugin(GetPluginNameStatic(),
+                                  GetPluginDescriptionStatic(), CreateInstance);
+  });
+}
+
+void ScriptedProcess::Terminate() {
+  PluginManager::UnregisterPlugin(ScriptedProcess::CreateInstance);
+}
+
+ConstString ScriptedProcess::GetPluginName() { return GetPluginNameStatic(); }
+
+uint32_t ScriptedProcess::GetPluginVersion() { return 1; }
+
+Status ScriptedProcess::DoLoadCore() {
+  ProcessLaunchInfo launch_info = GetTarget().GetProcessLaunchInfo();
+
+  return DoLaunch(nullptr, launch_info);
+}
+
+Status ScriptedProcess::DoLaunch(Module *exe_module,
+                                 ProcessLaunchInfo &launch_info) {
+  if (!m_interpreter)
+    return Status("No interpreter.");
+
+  if (!m_script_object_sp)
+    return Status("No python object.");
+
+  Status status = GetInterface().Launch();
+
+  if (status.Success()) {
+    SetPrivateState(eStateRunning);
+    SetPrivateState(eStateStopped);
+  }
+
+  return status;
+};
+
+void ScriptedProcess::DidLaunch() {
+  if (m_interpreter)
+    m_pid = GetInterface().GetProcessID();
+}
+
+Status ScriptedProcess::DoResume() {
+  if (!m_interpreter)
+    return Status("No interpreter.");
+
+  if (!m_script_object_sp)
+    return Status("No python object.");
+
+  Status status = GetInterface().Resume();
+
+  if (status.Success()) {
+    SetPrivateState(eStateRunning);
+    SetPrivateState(eStateStopped);
+  }
+
+  return status;
+}
+
+Status ScriptedProcess::DoDestroy() { return Status(); }
+
+bool ScriptedProcess::IsAlive() {
+  if (!m_interpreter)
+    return false;
+
+  return GetInterface().IsAlive();
+}
+
+size_t ScriptedProcess::ReadMemory(lldb::addr_t addr, void *buf, size_t size,
+                                   Status &error) {
+  return DoReadMemory(addr, buf, size, error);
+}
+
+size_t ScriptedProcess::DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
+                                     Status &error) {
+
+  auto error_with_message = [&error](llvm::StringRef message) {
+    error.SetErrorString(message);
+    return LLDB_INVALID_ADDRESS;
+  };
+
+  if (!m_interpreter)
+    return error_with_message("No interpreter.");
+
+  lldb::DataExtractorSP data_extractor_sp =
+      GetInterface().ReadMemoryAtAddress(addr, size, error);
+
+  if (!data_extractor_sp || error.Fail())
+    return LLDB_INVALID_ADDRESS;
+
+  if (data_extractor_sp->GetByteSize() != size)
+    return error_with_message("Failed to read requested memory size.");
+
+  offset_t bytes_copied = data_extractor_sp->CopyByteOrderedData(
+      0, size, buf, size, GetByteOrder());
+
+  if (!bytes_copied || bytes_copied == LLDB_INVALID_OFFSET)
+    return error_with_message("Failed to copy read memory to buffer.");
+
+  return size;
+}
+
+ArchSpec ScriptedProcess::GetArchitecture() {
+  return GetTarget().GetArchitecture();
+}
+
+Status ScriptedProcess::GetMemoryRegionInfo(lldb::addr_t load_addr,
+                                            MemoryRegionInfo &region) {
+  return Status();
+}
+
+Status ScriptedProcess::GetMemoryRegions(MemoryRegionInfos &region_list) {
+  Status error;
+
+  if (!m_interpreter) {
+    error.SetErrorString("No interpreter.");
+    return error;
+  }
+
+  lldb::addr_t address = 0;
+  lldb::MemoryRegionInfoSP mem_region_sp = nullptr;
+
+  while ((mem_region_sp =
+              GetInterface().GetMemoryRegionContainingAddress(address))) {
+    auto range = mem_region_sp->GetRange();
+    address += range.GetRangeBase() + range.GetByteSize();
+    region_list.push_back(*mem_region_sp.get());
+  }
+
+  return error;
+}
+
+void ScriptedProcess::Clear() { Process::m_thread_list.Clear(); }
+
+bool ScriptedProcess::DoUpdateThreadList(ThreadList &old_thread_list,
+                                         ThreadList &new_thread_list) {
+  return new_thread_list.GetSize(false) > 0;
+}
+
+bool ScriptedProcess::GetProcessInfo(ProcessInstanceInfo &info) {
+  info.Clear();
+  info.SetProcessID(GetID());
+  info.SetArchitecture(GetArchitecture());
+  lldb::ModuleSP module_sp = GetTarget().GetExecutableModule();
+  if (module_sp) {
+    const bool add_exe_file_as_first_arg = false;
+    info.SetExecutableFile(GetTarget().GetExecutableModule()->GetFileSpec(),
+                           add_exe_file_as_first_arg);
+  }
+  return true;
+}
+
+ScriptedProcessInterface &ScriptedProcess::GetInterface() const {
+  return m_interpreter->GetScriptedProcessInterface();
+}
diff --git a/source/Plugins/Process/scripted/ScriptedProcess.h b/source/Plugins/Process/scripted/ScriptedProcess.h
new file mode 100644
index 0000000..d8aced2
--- /dev/null
+++ b/source/Plugins/Process/scripted/ScriptedProcess.h
@@ -0,0 +1,113 @@
+//===-- ScriptedProcess.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_SOURCE_PLUGINS_SCRIPTED_PROCESS_H
+#define LLDB_SOURCE_PLUGINS_SCRIPTED_PROCESS_H
+
+#include "lldb/Target/Process.h"
+#include "lldb/Utility/ConstString.h"
+#include "lldb/Utility/Status.h"
+
+namespace lldb_private {
+
+class ScriptedProcess : public Process {
+protected:
+  class LaunchInfo {
+  public:
+    LaunchInfo(const ProcessLaunchInfo &launch_info) {
+      m_class_name = launch_info.GetScriptedProcessClassName();
+      m_dictionary_sp = launch_info.GetScriptedProcessDictionarySP();
+    }
+
+    std::string GetClassName() const { return m_class_name; }
+    StructuredData::DictionarySP GetDictionarySP() const {
+      return m_dictionary_sp;
+    }
+
+  private:
+    std::string m_class_name;
+    StructuredData::DictionarySP m_dictionary_sp;
+  };
+
+public:
+  static lldb::ProcessSP CreateInstance(lldb::TargetSP target_sp,
+                                        lldb::ListenerSP listener_sp,
+                                        const FileSpec *crash_file_path,
+                                        bool can_connect);
+
+  static void Initialize();
+
+  static void Terminate();
+
+  static ConstString GetPluginNameStatic();
+
+  static const char *GetPluginDescriptionStatic();
+
+  ScriptedProcess(lldb::TargetSP target_sp, lldb::ListenerSP listener_sp,
+                  const ScriptedProcess::LaunchInfo &launch_info);
+
+  ~ScriptedProcess() override;
+
+  bool CanDebug(lldb::TargetSP target_sp,
+                bool plugin_specified_by_name) override;
+
+  DynamicLoader *GetDynamicLoader() override { return nullptr; }
+
+  ConstString GetPluginName() override;
+
+  uint32_t GetPluginVersion() override;
+
+  SystemRuntime *GetSystemRuntime() override { return nullptr; }
+
+  Status DoLoadCore() override;
+
+  Status DoLaunch(Module *exe_module, ProcessLaunchInfo &launch_info) override;
+
+  void DidLaunch() override;
+
+  Status DoResume() override;
+
+  Status DoDestroy() override;
+
+  void RefreshStateAfterStop() override{};
+
+  bool IsAlive() override;
+
+  size_t ReadMemory(lldb::addr_t addr, void *buf, size_t size,
+                    Status &error) override;
+
+  size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
+                      Status &error) override;
+
+  ArchSpec GetArchitecture();
+
+  Status GetMemoryRegionInfo(lldb::addr_t load_addr,
+                             MemoryRegionInfo &range_info) override;
+
+  Status
+  GetMemoryRegions(lldb_private::MemoryRegionInfos &region_list) override;
+
+  bool GetProcessInfo(ProcessInstanceInfo &info) override;
+
+protected:
+  void Clear();
+
+  bool DoUpdateThreadList(ThreadList &old_thread_list,
+                          ThreadList &new_thread_list) override;
+
+private:
+  ScriptedProcessInterface &GetInterface() const;
+
+  const LaunchInfo m_launch_info;
+  lldb_private::ScriptInterpreter *m_interpreter = nullptr;
+  lldb_private::StructuredData::ObjectSP m_script_object_sp = nullptr;
+};
+
+} // namespace lldb_private
+
+#endif // LLDB_SOURCE_PLUGINS_SCRIPTED_PROCESS_H
diff --git a/source/Target/Target.cpp b/source/Target/Target.cpp
index c6667ce..762fb4f 100644
--- a/source/Target/Target.cpp
+++ b/source/Target/Target.cpp
@@ -2972,7 +2972,7 @@
   // If we're not already connected to the process, and if we have a platform
   // that can launch a process for debugging, go ahead and do that here.
   if (state != eStateConnected && platform_sp &&
-      platform_sp->CanDebugProcess()) {
+      platform_sp->CanDebugProcess() && !launch_info.IsScriptedProcess()) {
     LLDB_LOGF(log, "Target::%s asking the platform to debug the process",
               __FUNCTION__);
 
diff --git a/test/API/functionalities/scripted_process/TestScriptedProcess.py b/test/API/functionalities/scripted_process/TestScriptedProcess.py
index a5da070..5cf49ab 100644
--- a/test/API/functionalities/scripted_process/TestScriptedProcess.py
+++ b/test/API/functionalities/scripted_process/TestScriptedProcess.py
@@ -11,7 +11,7 @@
 from lldbsuite.test import lldbtest
 
 
-class PlatformProcessCrashInfoTestCase(TestBase):
+class ScriptedProcesTestCase(TestBase):
 
     mydir = TestBase.compute_mydir(__file__)
 
@@ -43,3 +43,55 @@
         self.expect('script dir(ScriptedProcess)',
                     substrs=["launch"])
 
+    def test_launch_scripted_process_sbapi(self):
+        """Test that we can launch an lldb scripted process using the SBAPI,
+        check its process ID and read string from memory."""
+        self.build()
+        target = self.dbg.CreateTarget(self.getBuildArtifact("a.out"))
+        self.assertTrue(target, VALID_TARGET)
+
+        scripted_process_example_relpath = ['..','..','..','..','examples','python','scripted_process','my_scripted_process.py']
+        os.environ['SKIP_SCRIPTED_PROCESS_LAUNCH'] = '1'
+        self.runCmd("command script import " + os.path.join(self.getSourceDir(),
+                                                            *scripted_process_example_relpath))
+
+        launch_info = lldb.SBLaunchInfo(None)
+        launch_info.SetProcessPluginName("ScriptedProcess")
+        launch_info.SetScriptedProcessClassName("my_scripted_process.MyScriptedProcess")
+
+        error = lldb.SBError()
+        process = target.Launch(launch_info, error)
+        self.assertTrue(process and process.IsValid(), PROCESS_IS_VALID)
+        self.assertEqual(process.GetProcessID(), 42)
+
+        hello_world = "Hello, world!"
+        memory_read = process.ReadCStringFromMemory(0x50000000000,
+                                                    len(hello_world) + 1, # NULL byte
+                                                    error)
+
+        self.assertTrue(error.Success(), "Failed to read memory from scripted process.")
+        self.assertEqual(hello_world, memory_read)
+
+    def test_launch_scripted_process_cli(self):
+        """Test that we can launch an lldb scripted process from the command
+        line, check its process ID and read string from memory."""
+        self.build()
+        target = self.dbg.CreateTarget(self.getBuildArtifact("a.out"))
+        self.assertTrue(target, VALID_TARGET)
+
+        scripted_process_example_relpath = ['..','..','..','..','examples','python','scripted_process','my_scripted_process.py']
+        self.runCmd("command script import " + os.path.join(self.getSourceDir(),
+                                                            *scripted_process_example_relpath))
+
+        process = target.GetProcess()
+        self.assertTrue(process, PROCESS_IS_VALID)
+        self.assertEqual(process.GetProcessID(), 42)
+
+        error = lldb.SBError()
+        hello_world = "Hello, world!"
+        memory_read = process.ReadCStringFromMemory(0x50000000000,
+                                                    len(hello_world) + 1, # NULL byte
+                                                    error)
+
+        self.assertTrue(error.Success(), "Failed to read memory from scripted process.")
+        self.assertEqual(hello_world, memory_read)