[lldb] Move PassthroughScriptedProcess to lldb.scripted_process module

This patch moves the `PassthroughScriptedProcess` & `PassthroughScriptedThread`
classes from the `interactive_scripted_process.py` test implementation
to the `lldb.scripted_process` python module.

This class is very versatile so it makes more sense to ship it with the
python module to make it easier for our adopters to derive their class
from it instead of copying it.

During the "migration", I've also noticed some bugs in the
`PassthroughScriptedThread` creation and update, so I also fixed that as
part of this patch.

Differential Revision: https://reviews.llvm.org/D151044

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

lldb/examples/python/scripted_process/scripted_process.py

@@ -1,6 +1,7 @@
 from abc import ABCMeta, abstractmethod
 
 import lldb
+import json, struct, signal
 
 class ScriptedProcess(metaclass=ABCMeta):
 
@@ -225,7 +226,6 @@ def create_breakpoint(self, addr, error):
                              % self.__class__.__name__)
         return False
 
-
 class ScriptedThread(metaclass=ABCMeta):
 
     """
@@ -376,6 +376,162 @@ def get_extended_info(self):
         """
         return self.extended_info
 
+
+class PassthroughScriptedProcess(ScriptedProcess):
+    driving_target = None
+    driving_process = None
+
+    def __init__(self, exe_ctx, args, launched_driving_process=True):
+        super().__init__(exe_ctx, args)
+
+        self.driving_target = None
+        self.driving_process = None
+
+        self.driving_target_idx = args.GetValueForKey("driving_target_idx")
+        if self.driving_target_idx and self.driving_target_idx.IsValid():
+            idx = self.driving_target_idx.GetUnsignedIntegerValue(42)
+            self.driving_target = self.target.GetDebugger().GetTargetAtIndex(idx)
+
+            if launched_driving_process:
+                self.driving_process = self.driving_target.GetProcess()
+                for driving_thread in self.driving_process:
+                    structured_data = lldb.SBStructuredData()
+                    structured_data.SetFromJSON(
+                        json.dumps(
+                            {
+                                "driving_target_idx": idx,
+                                "thread_idx": driving_thread.GetIndexID(),
+                            }
+                        )
+                    )
+
+                    self.threads[
+                        driving_thread.GetThreadID()
+                    ] = PassthroughScriptedThread(self, structured_data)
+
+                for module in self.driving_target.modules:
+                    path = module.file.fullpath
+                    load_addr = module.GetObjectFileHeaderAddress().GetLoadAddress(
+                        self.driving_target
+                    )
+                    self.loaded_images.append({"path": path, "load_addr": load_addr})
+
+    def get_memory_region_containing_address(self, addr):
+        mem_region = lldb.SBMemoryRegionInfo()
+        error = self.driving_process.GetMemoryRegionInfo(addr, mem_region)
+        if error.Fail():
+            return None
+        return mem_region
+
+    def read_memory_at_address(self, addr, size, error):
+        data = lldb.SBData()
+        bytes_read = self.driving_process.ReadMemory(addr, size, error)
+
+        if error.Fail():
+            return data
+
+        data.SetDataWithOwnership(
+            error,
+            bytes_read,
+            self.driving_target.GetByteOrder(),
+            self.driving_target.GetAddressByteSize(),
+        )
+
+        return data
+
+    def write_memory_at_address(self, addr, data, error):
+        return self.driving_process.WriteMemory(
+            addr, bytearray(data.uint8.all()), error
+        )
+
+    def get_process_id(self):
+        return self.driving_process.GetProcessID()
+
+    def is_alive(self):
+        return True
+
+    def get_scripted_thread_plugin(self):
+        return f"{PassthroughScriptedThread.__module__}.{PassthroughScriptedThread.__name__}"
+
+
+class PassthroughScriptedThread(ScriptedThread):
+    def __init__(self, process, args):
+        super().__init__(process, args)
+        driving_target_idx = args.GetValueForKey("driving_target_idx")
+        thread_idx = args.GetValueForKey("thread_idx")
+
+        # TODO: Change to Walrus operator (:=) with oneline if assignment
+        # Requires python 3.8
+        val = thread_idx.GetUnsignedIntegerValue()
+        if val is not None:
+            self.idx = val
+
+        self.driving_target = None
+        self.driving_process = None
+        self.driving_thread = None
+
+        # TODO: Change to Walrus operator (:=) with oneline if assignment
+        # Requires python 3.8
+        val = driving_target_idx.GetUnsignedIntegerValue()
+        if val is not None:
+            self.driving_target = self.target.GetDebugger().GetTargetAtIndex(val)
+            self.driving_process = self.driving_target.GetProcess()
+            self.driving_thread = self.driving_process.GetThreadByIndexID(self.idx)
+
+        if self.driving_thread:
+            self.id = self.driving_thread.GetThreadID()
+
+    def get_thread_id(self):
+        return self.id
+
+    def get_name(self):
+        return f"{PassthroughScriptedThread.__name__}.thread-{self.idx}"
+
+    def get_stop_reason(self):
+        stop_reason = {"type": lldb.eStopReasonInvalid, "data": {}}
+
+        if (
+            self.driving_thread
+            and self.driving_thread.IsValid()
+            and self.get_thread_id() == self.driving_thread.GetThreadID()
+        ):
+            stop_reason["type"] = lldb.eStopReasonNone
+
+            # TODO: Passthrough stop reason from driving process
+            if self.driving_thread.GetStopReason() != lldb.eStopReasonNone:
+                if "arm64" in self.scripted_process.arch:
+                    stop_reason["type"] = lldb.eStopReasonException
+                    stop_reason["data"][
+                        "desc"
+                    ] = self.driving_thread.GetStopDescription(100)
+                elif self.scripted_process.arch == "x86_64":
+                    stop_reason["type"] = lldb.eStopReasonSignal
+                    stop_reason["data"]["signal"] = signal.SIGTRAP
+                else:
+                    stop_reason["type"] = self.driving_thread.GetStopReason()
+
+        return stop_reason
+
+    def get_register_context(self):
+        if not self.driving_thread or self.driving_thread.GetNumFrames() == 0:
+            return None
+        frame = self.driving_thread.GetFrameAtIndex(0)
+
+        GPRs = None
+        registerSet = frame.registers  # Returns an SBValueList.
+        for regs in registerSet:
+            if "general purpose" in regs.name.lower():
+                GPRs = regs
+                break
+
+        if not GPRs:
+            return None
+
+        for reg in GPRs:
+            self.register_ctx[reg.name] = int(reg.value, base=16)
+
+        return struct.pack(f"{len(self.register_ctx)}Q", *self.register_ctx.values())
+
 ARM64_GPR = [ {'name': 'x0',   'bitsize': 64, 'offset': 0,   'encoding': 'uint', 'format': 'hex', 'set': 0, 'gcc': 0,  'dwarf': 0,  'generic': 'arg0', 'alt-name': 'arg0'},
               {'name': 'x1',   'bitsize': 64, 'offset': 8,   'encoding': 'uint', 'format': 'hex', 'set': 0, 'gcc': 1,  'dwarf': 1,  'generic': 'arg1', 'alt-name': 'arg1'},
               {'name': 'x2',   'bitsize': 64, 'offset': 16,  'encoding': 'uint', 'format': 'hex', 'set': 0, 'gcc': 2,  'dwarf': 2,  'generic': 'arg2', 'alt-name': 'arg2'},