[lldb/Plugins] Add ability to load modules to Scripted Processes

This patch introduces a new way to load modules programatically with
Scripted Processes. To do so, the scripted process blueprint holds a
list of dictionary describing the modules to load, which their path or
uuid, load address and eventually a slide offset.

LLDB will fetch that list after launching the ScriptedProcess, and
iterate over each entry to create the module that will be loaded in the
Scripted Process' target.

The patch also refactors the StackCoreScriptedProcess test to stop
inside the `libbaz` module and make sure it's loaded correctly and that
we can fetch some variables from it.

rdar://74520238

Differential Revision: https://reviews.llvm.org/D120969

Signed-off-by: Med Ismail Bennani <[email protected]>

Author: medismailben

lldb/examples/python/scripted_process/scripted_process.py

@@ -19,7 +19,7 @@ class ScriptedProcess:
     memory_regions = None
     stack_memory_dump = None
     loaded_images = None
-    threads = {}
+    threads = None
 
     @abstractmethod
     def __init__(self, target, args):
@@ -41,6 +41,8 @@ def __init__(self, target, args):
             self.dbg = target.GetDebugger()
         if isinstance(args, lldb.SBStructuredData) and args.IsValid():
             self.args = args
+        self.threads = {}
+        self.loaded_images = []
 
     @abstractmethod
     def get_memory_region_containing_address(self, addr):
@@ -116,8 +118,7 @@ def get_loaded_images(self):
 
         ```
         class ScriptedProcessImage:
-            def __init__(name, file_spec, uuid, load_address):
-              self.name = name
+            def __init__(file_spec, uuid, load_address):
               self.file_spec = file_spec
               self.uuid = uuid
               self.load_address = load_address

lldb/include/lldb/Interpreter/ScriptedProcessInterface.h

@@ -57,7 +57,7 @@ class ScriptedProcessInterface : virtual public ScriptedInterface {
     return nullptr;
   }
 
-  virtual StructuredData::DictionarySP GetLoadedImages() { return nullptr; }
+  virtual StructuredData::ArraySP GetLoadedImages() { return nullptr; }
 
   virtual lldb::pid_t GetProcessID() { return LLDB_INVALID_PROCESS_ID; }
 

lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp

@@ -170,6 +170,7 @@ Status ScriptedProcess::DoLaunch(Module *exe_module,
 void ScriptedProcess::DidLaunch() {
   CheckInterpreterAndScriptObject();
   m_pid = GetInterface().GetProcessID();
+  GetLoadedDynamicLibrariesInfos();
 }
 
 Status ScriptedProcess::DoResume() {
@@ -378,6 +379,93 @@ bool ScriptedProcess::GetProcessInfo(ProcessInstanceInfo &info) {
   return true;
 }
 
+lldb_private::StructuredData::ObjectSP
+ScriptedProcess::GetLoadedDynamicLibrariesInfos() {
+  CheckInterpreterAndScriptObject();
+
+  Status error;
+  auto error_with_message = [&error](llvm::StringRef message) {
+    return ScriptedInterface::ErrorWithMessage<bool>(LLVM_PRETTY_FUNCTION,
+                                                     message.data(), error);
+  };
+
+  StructuredData::ArraySP loaded_images_sp = GetInterface().GetLoadedImages();
+
+  if (!loaded_images_sp || !loaded_images_sp->GetSize())
+    return GetInterface().ErrorWithMessage<StructuredData::ObjectSP>(
+        LLVM_PRETTY_FUNCTION, "No loaded images.", error);
+
+  ModuleList module_list;
+  Target &target = GetTarget();
+
+  auto reload_image = [&target, &module_list, &error_with_message](
+                          StructuredData::Object *obj) -> bool {
+    StructuredData::Dictionary *dict = obj->GetAsDictionary();
+
+    if (!dict)
+      return error_with_message("Couldn't cast image object into dictionary.");
+
+    ModuleSpec module_spec;
+    llvm::StringRef value;
+
+    bool has_path = dict->HasKey("path");
+    bool has_uuid = dict->HasKey("uuid");
+    if (!has_path && !has_uuid)
+      return error_with_message("Dictionary should have key 'path' or 'uuid'");
+    if (!dict->HasKey("load_addr"))
+      return error_with_message("Dictionary is missing key 'load_addr'");
+
+    if (has_path) {
+      dict->GetValueForKeyAsString("path", value);
+      module_spec.GetFileSpec().SetPath(value);
+    }
+
+    if (has_uuid) {
+      dict->GetValueForKeyAsString("uuid", value);
+      module_spec.GetUUID().SetFromStringRef(value);
+    }
+    module_spec.GetArchitecture() = target.GetArchitecture();
+
+    ModuleSP module_sp =
+        target.GetOrCreateModule(module_spec, true /* notify */);
+
+    if (!module_sp)
+      return error_with_message("Couldn't create or get module.");
+
+    lldb::addr_t load_addr = LLDB_INVALID_ADDRESS;
+    lldb::addr_t slide = LLDB_INVALID_OFFSET;
+    dict->GetValueForKeyAsInteger("load_addr", load_addr);
+    dict->GetValueForKeyAsInteger("slide", slide);
+    if (load_addr == LLDB_INVALID_ADDRESS)
+      return error_with_message(
+          "Couldn't get valid load address or slide offset.");
+
+    if (slide != LLDB_INVALID_OFFSET)
+      load_addr += slide;
+
+    bool changed = false;
+    module_sp->SetLoadAddress(target, load_addr, false /*=value_is_offset*/,
+                              changed);
+
+    if (!changed && !module_sp->GetObjectFile())
+      return error_with_message("Couldn't set the load address for module.");
+
+    dict->GetValueForKeyAsString("path", value);
+    FileSpec objfile(value);
+    module_sp->SetFileSpecAndObjectName(objfile, objfile.GetFilename());
+
+    return module_list.AppendIfNeeded(module_sp);
+  };
+
+  if (!loaded_images_sp->ForEach(reload_image))
+    return GetInterface().ErrorWithMessage<StructuredData::ObjectSP>(
+        LLVM_PRETTY_FUNCTION, "Couldn't reload all images.", error);
+
+  target.ModulesDidLoad(module_list);
+
+  return loaded_images_sp;
+}
+
 ScriptedProcessInterface &ScriptedProcess::GetInterface() const {
   return m_interpreter->GetScriptedProcessInterface();
 }

lldb/source/Plugins/Process/scripted/ScriptedProcess.h

@@ -89,6 +89,9 @@ class ScriptedProcess : public Process {
 
   bool GetProcessInfo(ProcessInstanceInfo &info) override;
 
+  lldb_private::StructuredData::ObjectSP
+  GetLoadedDynamicLibrariesInfos() override;
+
 protected:
   Status DoStop();
 

lldb/source/Plugins/ScriptInterpreter/Python/ScriptedProcessPythonInterface.cpp

@@ -124,9 +124,21 @@ lldb::DataExtractorSP ScriptedProcessPythonInterface::ReadMemoryAtAddress(
                                          address, size);
 }
 
-StructuredData::DictionarySP ScriptedProcessPythonInterface::GetLoadedImages() {
-  // TODO: Implement
-  return {};
+StructuredData::ArraySP ScriptedProcessPythonInterface::GetLoadedImages() {
+  Status error;
+  StructuredData::ArraySP array =
+      Dispatch<StructuredData::ArraySP>("get_loaded_images", error);
+
+  if (!array || !array->IsValid() || error.Fail()) {
+    return ScriptedInterface::ErrorWithMessage<StructuredData::ArraySP>(
+        LLVM_PRETTY_FUNCTION,
+        llvm::Twine("Null or invalid object (" +
+                    llvm::Twine(error.AsCString()) + llvm::Twine(")."))
+            .str(),
+        error);
+  }
+
+  return array;
 }
 
 lldb::pid_t ScriptedProcessPythonInterface::GetProcessID() {

lldb/source/Plugins/ScriptInterpreter/Python/ScriptedProcessPythonInterface.h

@@ -49,7 +49,7 @@ class ScriptedProcessPythonInterface : public ScriptedProcessInterface,
   lldb::DataExtractorSP ReadMemoryAtAddress(lldb::addr_t address, size_t size,
                                             Status &error) override;
 
-  StructuredData::DictionarySP GetLoadedImages() override;
+  StructuredData::ArraySP GetLoadedImages() override;
 
   lldb::pid_t GetProcessID() override;
 

lldb/test/API/functionalities/scripted_process/Makefile

@@ -1,4 +1,13 @@
 CXX_SOURCES := main.cpp
 ENABLE_THREADS := YES
-include Makefile.rules
+LD_EXTRAS := -L. -lbaz -I.
+
+override ARCH := $(shell uname -m)
+
+all: libbaz.dylib a.out
 
+libbaz.dylib: baz.c
+	$(MAKE) -f $(MAKEFILE_RULES) ARCH=$(ARCH) \
+		DYLIB_ONLY=YES DYLIB_NAME=baz DYLIB_C_SOURCES=baz.c
+
+include Makefile.rules

lldb/test/API/functionalities/scripted_process/TestStackCoreScriptedProcess.py

@@ -25,13 +25,19 @@ def tearDown(self):
     def create_stack_skinny_corefile(self, file):
         self.build()
         target, process, thread, _ = lldbutil.run_to_source_breakpoint(self, "// break here",
-                                                                       lldb.SBFileSpec("main.cpp"))
+                                                                       lldb.SBFileSpec("baz.c"))
         self.assertTrue(process.IsValid(), "Process is invalid.")
         # FIXME: Use SBAPI to save the process corefile.
         self.runCmd("process save-core -s stack  " + file)
         self.assertTrue(os.path.exists(file), "No stack-only corefile found.")
         self.assertTrue(self.dbg.DeleteTarget(target), "Couldn't delete target")
 
+    def get_module_with_name(self, target, name):
+        for module in target.modules:
+            if name in module.GetFileSpec().GetFilename():
+                return module
+        return None
+
     @skipUnlessDarwin
     @skipIfOutOfTreeDebugserver
     def test_launch_scripted_process_stack_frames(self):
@@ -41,15 +47,15 @@ def test_launch_scripted_process_stack_frames(self):
         target = self.dbg.CreateTarget(self.getBuildArtifact("a.out"))
         self.assertTrue(target, VALID_TARGET)
 
-        for module in target.modules:
-            if 'a.out' in module.GetFileSpec().GetFilename():
-                main_module = module
-                break
-
+        main_module = self.get_module_with_name(target, 'a.out')
         self.assertTrue(main_module, "Invalid main module.")
         error = target.SetModuleLoadAddress(main_module, 0)
         self.assertSuccess(error, "Reloading main module at offset 0 failed.")
 
+        scripted_dylib = self.get_module_with_name(target, 'libbaz.dylib')
+        self.assertTrue(scripted_dylib, "Dynamic library libbaz.dylib not found.")
+        self.assertEqual(scripted_dylib.GetObjectFileHeaderAddress().GetLoadAddress(target), 0xffffffffffffffff)
+
         os.environ['SKIP_SCRIPTED_PROCESS_LAUNCH'] = '1'
         def cleanup():
           del os.environ["SKIP_SCRIPTED_PROCESS_LAUNCH"]
@@ -68,7 +74,8 @@ def cleanup():
 
         structured_data = lldb.SBStructuredData()
         structured_data.SetFromJSON(json.dumps({
-            "backing_target_idx" : self.dbg.GetIndexOfTarget(corefile_process.GetTarget())
+            "backing_target_idx" : self.dbg.GetIndexOfTarget(corefile_process.GetTarget()),
+            "libbaz_path" : self.getBuildArtifact("libbaz.dylib")
         }))
         launch_info = lldb.SBLaunchInfo(None)
         launch_info.SetProcessPluginName("ScriptedProcess")
@@ -81,10 +88,10 @@ def cleanup():
         self.assertTrue(process, PROCESS_IS_VALID)
         self.assertEqual(process.GetProcessID(), 42)
 
-        self.assertEqual(process.GetNumThreads(), 3)
+        self.assertEqual(process.GetNumThreads(), 2)
         thread = process.GetSelectedThread()
         self.assertTrue(thread, "Invalid thread.")
-        self.assertEqual(thread.GetName(), "StackCoreScriptedThread.thread-2")
+        self.assertEqual(thread.GetName(), "StackCoreScriptedThread.thread-1")
 
         self.assertTrue(target.triple, "Invalid target triple")
         arch = target.triple.split('-')[0]
@@ -102,9 +109,17 @@ def cleanup():
         else:
             self.assertTrue(thread.GetStopReason(), lldb.eStopReasonSignal)
 
-        self.assertEqual(thread.GetNumFrames(), 6)
+        self.assertEqual(thread.GetNumFrames(), 5)
         frame = thread.GetSelectedFrame()
         self.assertTrue(frame, "Invalid frame.")
-        self.assertIn("bar", frame.GetFunctionName())
-        self.assertEqual(int(frame.FindValue("i", lldb.eValueTypeVariableArgument).GetValue()), 42)
-        self.assertEqual(int(frame.FindValue("j", lldb.eValueTypeVariableLocal).GetValue()), 42 * 42)
+        func = frame.GetFunction()
+        self.assertTrue(func, "Invalid function.")
+
+        self.assertIn("baz", frame.GetFunctionName())
+        self.assertEqual(frame.vars.GetSize(), 2)
+        self.assertEqual(int(frame.vars.GetFirstValueByName('j').GetValue()), 42 * 42)
+        self.assertEqual(int(frame.vars.GetFirstValueByName('k').GetValue()), 42)
+
+        scripted_dylib = self.get_module_with_name(target, 'libbaz.dylib')
+        self.assertTrue(scripted_dylib, "Dynamic library libbaz.dylib not found.")
+        self.assertEqual(scripted_dylib.GetObjectFileHeaderAddress().GetLoadAddress(target), 0x1001e0000)

lldb/test/API/functionalities/scripted_process/baz.c

@@ -0,0 +1,8 @@
+#include "baz.h"
+
+#include <math.h>
+
+int baz(int j) {
+  int k = sqrt(j);
+  return k; // break here
+}

lldb/test/API/functionalities/scripted_process/baz.h

@@ -0,0 +1,3 @@
+#pragma once
+
+int baz(int j);

lldb/test/API/functionalities/scripted_process/main.cpp

@@ -2,16 +2,20 @@
 #include <mutex>
 #include <thread>
 
+extern "C" {
+int baz(int);
+}
+
 int bar(int i) {
   int j = i * i;
-  return j; // break here
+  return j;
 }
 
 int foo(int i) { return bar(i); }
 
 void call_and_wait(int &n) {
   std::cout << "waiting for computation!" << std::endl;
-  while (n != 42 * 42)
+  while (baz(n) != 42)
     ;
   std::cout << "finished computation!" << std::endl;
 }

lldb/test/API/functionalities/scripted_process/stack_core_scripted_process.py

@@ -7,13 +7,19 @@
 from lldb.plugins.scripted_process import ScriptedThread
 
 class StackCoreScriptedProcess(ScriptedProcess):
+    def get_module_with_name(self, target, name):
+        for module in target.modules:
+            if name in module.GetFileSpec().GetFilename():
+                return module
+        return None
+
     def __init__(self, target: lldb.SBTarget, args : lldb.SBStructuredData):
         super().__init__(target, args)
 
-        self.backing_target_idx = args.GetValueForKey("backing_target_idx")
-
         self.corefile_target = None
         self.corefile_process = None
+
+        self.backing_target_idx = args.GetValueForKey("backing_target_idx")
         if (self.backing_target_idx and self.backing_target_idx.IsValid()):
             if self.backing_target_idx.GetType() == lldb.eStructuredDataTypeInteger:
                 idx = self.backing_target_idx.GetIntegerValue(42)
@@ -30,9 +36,22 @@ def __init__(self, target: lldb.SBTarget, args : lldb.SBStructuredData):
 
                 self.threads[corefile_thread.GetThreadID()] = StackCoreScriptedThread(self, structured_data)
 
-        if len(self.threads) == 3:
+        if len(self.threads) == 2:
             self.threads[len(self.threads) - 1].is_stopped = True
 
+        corefile_module = self.get_module_with_name(self.corefile_target,
+                                                    "libbaz.dylib")
+        if not corefile_module or not corefile_module.IsValid():
+            return
+        module_path = os.path.join(corefile_module.GetFileSpec().GetDirectory(),
+                                   corefile_module.GetFileSpec().GetFilename())
+        if not os.path.exists(module_path):
+            return
+        module_load_addr = corefile_module.GetObjectFileHeaderAddress().GetLoadAddress(self.corefile_target)
+
+        self.loaded_images.append({"path": module_path,
+                                   "load_addr": module_load_addr})
+
     def get_memory_region_containing_address(self, addr: int) -> lldb.SBMemoryRegionInfo:
         mem_region = lldb.SBMemoryRegionInfo()
         error = self.corefile_process.GetMemoryRegionInfo(addr, mem_region)
@@ -61,8 +80,6 @@ def read_memory_at_address(self, addr: int, size: int) -> lldb.SBData:
         return data
 
     def get_loaded_images(self):
-        # TODO: Iterate over corefile_target modules and build a data structure
-        # from it.
         return self.loaded_images
 
     def get_process_id(self) -> int: