[lldb] Introduce ScriptedFrame affordance (#149622)

This patch introduces a new scripting affordance in lldb:
`ScriptedFrame`.

This allows user to produce mock stackframes in scripted threads and
scripted processes from a python script.

With this change, StackFrame can be synthetized from different sources:
- Either from a dictionary containing a load address, and a frame index,
  which is the legacy way.
- Or by creating a ScriptedFrame python object.

One particularity of synthezising stackframes from the ScriptedFrame
python object, is that these frame have an optional PC, meaning that
they don't have a report a valid PC and they can act as shells that just
contain static information, like the frame function name, the list of
variables or registers, etc. It can also provide a symbol context.

rdar://157260006

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>

7 files changed, 242 insertions, 1 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/CMakeLists.txt b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/CMakeLists.txt
index 0437094..0910357 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/CMakeLists.txt
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/CMakeLists.txt
@@ -22,6 +22,7 @@ endif()
 add_lldb_library(lldbPluginScriptInterpreterPythonInterfaces PLUGIN
   OperatingSystemPythonInterface.cpp
   ScriptInterpreterPythonInterfaces.cpp
+  ScriptedFramePythonInterface.cpp
   ScriptedPlatformPythonInterface.cpp
   ScriptedProcessPythonInterface.cpp
   ScriptedPythonInterface.cpp
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptInterpreterPythonInterfaces.h b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptInterpreterPythonInterfaces.h
index 02dc065..3814f46 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptInterpreterPythonInterfaces.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptInterpreterPythonInterfaces.h
@@ -17,6 +17,7 @@
 
 #include "OperatingSystemPythonInterface.h"
 #include "ScriptedBreakpointPythonInterface.h"
+#include "ScriptedFramePythonInterface.h"
 #include "ScriptedPlatformPythonInterface.h"
 #include "ScriptedProcessPythonInterface.h"
 #include "ScriptedStopHookPythonInterface.h"
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedFramePythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedFramePythonInterface.cpp
new file mode 100644
index 0000000..20ca7a2
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedFramePythonInterface.cpp
@@ -0,0 +1,157 @@
+//===----------------------------------------------------------------------===//
+//
+// 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/Host/Config.h"
+#include "lldb/Target/ExecutionContext.h"
+#include "lldb/Utility/Log.h"
+#include "lldb/lldb-enumerations.h"
+
+#if LLDB_ENABLE_PYTHON
+
+// LLDB Python header must be included first
+#include "../lldb-python.h"
+
+#include "../SWIGPythonBridge.h"
+#include "../ScriptInterpreterPythonImpl.h"
+#include "ScriptedFramePythonInterface.h"
+#include <optional>
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::python;
+using Locker = ScriptInterpreterPythonImpl::Locker;
+
+ScriptedFramePythonInterface::ScriptedFramePythonInterface(
+    ScriptInterpreterPythonImpl &interpreter)
+    : ScriptedFrameInterface(), ScriptedPythonInterface(interpreter) {}
+
+llvm::Expected<StructuredData::GenericSP>
+ScriptedFramePythonInterface::CreatePluginObject(
+    const llvm::StringRef class_name, ExecutionContext &exe_ctx,
+    StructuredData::DictionarySP args_sp, StructuredData::Generic *script_obj) {
+  ExecutionContextRefSP exe_ctx_ref_sp =
+      std::make_shared<ExecutionContextRef>(exe_ctx);
+  StructuredDataImpl sd_impl(args_sp);
+  return ScriptedPythonInterface::CreatePluginObject(class_name, script_obj,
+                                                     exe_ctx_ref_sp, sd_impl);
+}
+
+lldb::user_id_t ScriptedFramePythonInterface::GetID() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("get_id", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return LLDB_INVALID_FRAME_ID;
+
+  return obj->GetUnsignedIntegerValue(LLDB_INVALID_FRAME_ID);
+}
+
+lldb::addr_t ScriptedFramePythonInterface::GetPC() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("get_pc", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return LLDB_INVALID_ADDRESS;
+
+  return obj->GetUnsignedIntegerValue(LLDB_INVALID_ADDRESS);
+}
+
+std::optional<SymbolContext> ScriptedFramePythonInterface::GetSymbolContext() {
+  Status error;
+  auto sym_ctx = Dispatch<SymbolContext>("get_symbol_context", error);
+
+  if (error.Fail()) {
+    return ErrorWithMessage<SymbolContext>(LLVM_PRETTY_FUNCTION,
+                                           error.AsCString(), error);
+  }
+
+  return sym_ctx;
+}
+
+std::optional<std::string> ScriptedFramePythonInterface::GetFunctionName() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("get_function_name", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return {};
+
+  return obj->GetStringValue().str();
+}
+
+std::optional<std::string>
+ScriptedFramePythonInterface::GetDisplayFunctionName() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("get_display_function_name", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return {};
+
+  return obj->GetStringValue().str();
+}
+
+bool ScriptedFramePythonInterface::IsInlined() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("is_inlined", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return false;
+
+  return obj->GetBooleanValue();
+}
+
+bool ScriptedFramePythonInterface::IsArtificial() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("is_artificial", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return false;
+
+  return obj->GetBooleanValue();
+}
+
+bool ScriptedFramePythonInterface::IsHidden() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("is_hidden", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return false;
+
+  return obj->GetBooleanValue();
+}
+
+StructuredData::DictionarySP ScriptedFramePythonInterface::GetRegisterInfo() {
+  Status error;
+  StructuredData::DictionarySP dict =
+      Dispatch<StructuredData::DictionarySP>("get_register_info", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, dict,
+                                                    error))
+    return {};
+
+  return dict;
+}
+
+std::optional<std::string> ScriptedFramePythonInterface::GetRegisterContext() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("get_register_context", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return {};
+
+  return obj->GetAsString()->GetValue().str();
+}
+
+#endif
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedFramePythonInterface.h b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedFramePythonInterface.h
new file mode 100644
index 0000000..3aff237
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedFramePythonInterface.h
@@ -0,0 +1,59 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_PLUGINS_SCRIPTINTERPRETER_PYTHON_INTERFACES_SCRIPTEDFRAMEPYTHONINTERFACE_H
+#define LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_INTERFACES_SCRIPTEDFRAMEPYTHONINTERFACE_H
+
+#include "lldb/Host/Config.h"
+
+#if LLDB_ENABLE_PYTHON
+
+#include "ScriptedPythonInterface.h"
+#include "lldb/Interpreter/Interfaces/ScriptedFrameInterface.h"
+#include <optional>
+
+namespace lldb_private {
+class ScriptedFramePythonInterface : public ScriptedFrameInterface,
+                                     public ScriptedPythonInterface {
+public:
+  ScriptedFramePythonInterface(ScriptInterpreterPythonImpl &interpreter);
+
+  llvm::Expected<StructuredData::GenericSP>
+  CreatePluginObject(llvm::StringRef class_name, ExecutionContext &exe_ctx,
+                     StructuredData::DictionarySP args_sp,
+                     StructuredData::Generic *script_obj = nullptr) override;
+
+  llvm::SmallVector<AbstractMethodRequirement>
+  GetAbstractMethodRequirements() const override {
+    return llvm::SmallVector<AbstractMethodRequirement>({{"get_id"}});
+  }
+
+  lldb::user_id_t GetID() override;
+
+  lldb::addr_t GetPC() override;
+
+  std::optional<SymbolContext> GetSymbolContext() override;
+
+  std::optional<std::string> GetFunctionName() override;
+
+  std::optional<std::string> GetDisplayFunctionName() override;
+
+  bool IsInlined() override;
+
+  bool IsArtificial() override;
+
+  bool IsHidden() override;
+
+  StructuredData::DictionarySP GetRegisterInfo() override;
+
+  std::optional<std::string> GetRegisterContext() override;
+};
+} // namespace lldb_private
+
+#endif // LLDB_ENABLE_PYTHON
+#endif // LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_INTERFACES_SCRIPTEDFRAMEPYTHONINTERFACE_H
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.cpp
index b49d1d8..8083cca 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.cpp
@@ -167,7 +167,8 @@ ScriptedPythonInterface::ExtractValueFromPythonObject<
 
   if (!sb_mem_reg_info) {
     error = Status::FromErrorStringWithFormat(
-        "Couldn't cast lldb::SBMemoryRegionInfo to lldb::MemoryRegionInfoSP.");
+        "Couldn't cast lldb::SBMemoryRegionInfo to "
+        "lldb_private::MemoryRegionInfo.");
     return {};
   }
 
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.cpp
index 8af89d7..fd4d231 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.cpp
@@ -144,4 +144,21 @@ StructuredData::ArraySP ScriptedThreadPythonInterface::GetExtendedInfo() {
   return arr;
 }
 
+std::optional<std::string>
+ScriptedThreadPythonInterface::GetScriptedFramePluginName() {
+  Status error;
+  StructuredData::ObjectSP obj = Dispatch("get_scripted_frame_plugin", error);
+
+  if (!ScriptedInterface::CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj,
+                                                    error))
+    return {};
+
+  return obj->GetStringValue().str();
+}
+
+lldb::ScriptedFrameInterfaceSP
+ScriptedThreadPythonInterface::CreateScriptedFrameInterface() {
+  return m_interpreter.CreateScriptedFrameInterface();
+}
+
 #endif
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.h b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.h
index 1fb23b3..043557a 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.h
@@ -51,6 +51,11 @@ public:
   std::optional<std::string> GetRegisterContext() override;
 
   StructuredData::ArraySP GetExtendedInfo() override;
+
+  std::optional<std::string> GetScriptedFramePluginName() override;
+
+protected:
+  lldb::ScriptedFrameInterfaceSP CreateScriptedFrameInterface() override;
 };
 } // namespace lldb_private