[lldb/Plugins] Add ScriptedProcess::GetCapabilities affordance (NFC)

This patch introduces a new method to the Scripted Process interface,
GetCapabilities.

This returns a dictionary that contains a list of flags that the
ScriptedProcess instance supports. This can be used for instance, to
force symbol lookup, when loading dynamic libraries in the scripted process.

Differential Revision: https://reviews.llvm.org/D142059

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

Author: medismailben

lldb/examples/python/scripted_process/scripted_process.py

@@ -14,6 +14,7 @@ class ScriptedProcess(metaclass=ABCMeta):
                 THE METHODS EXPOSED MIGHT CHANGE IN THE FUTURE.
     """
 
+    capabilities = None
     memory_regions = None
     loaded_images = None
     threads = None
@@ -42,6 +43,17 @@ def __init__(self, target, args):
         self.threads = {}
         self.loaded_images = []
         self.metadata = {}
+        self.capabilities = {}
+
+    def get_capabilities(self):
+        """ Get a dictionary containing the process capabilities.
+
+        Returns:
+            Dict[str:bool]: The dictionary of capability, with the capability
+            name as the key and a boolean flag as the value.
+            The dictionary can be empty.
+        """
+        return self.capabilities
 
     @abstractmethod
     def get_memory_region_containing_address(self, addr):

lldb/include/lldb/Interpreter/ScriptedProcessInterface.h

@@ -27,6 +27,8 @@ class ScriptedProcessInterface : virtual public ScriptedInterface {
     return {};
   }
 
+  virtual StructuredData::DictionarySP GetCapabilities() { return {}; }
+
   virtual Status Launch() { return Status("ScriptedProcess did not launch"); }
 
   virtual Status Resume() { return Status("ScriptedProcess did not resume"); }

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

@@ -53,6 +53,17 @@ StructuredData::GenericSP ScriptedProcessPythonInterface::CreatePluginObject(
   return m_object_instance_sp;
 }
 
+StructuredData::DictionarySP ScriptedProcessPythonInterface::GetCapabilities() {
+  Status error;
+  StructuredData::DictionarySP dict =
+      Dispatch<StructuredData::DictionarySP>("get_capabilities", error);
+
+  if (!CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, dict, error))
+    return {};
+
+  return dict;
+}
+
 Status ScriptedProcessPythonInterface::Launch() {
   return GetStatusFromMethod("launch");
 }
@@ -137,14 +148,8 @@ StructuredData::ArraySP ScriptedProcessPythonInterface::GetLoadedImages() {
   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);
-  }
+  if (!CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, array, error))
+    return {};
 
   return array;
 }

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

@@ -28,6 +28,8 @@ class ScriptedProcessPythonInterface : public ScriptedProcessInterface,
                      StructuredData::DictionarySP args_sp,
                      StructuredData::Generic *script_obj = nullptr) override;
 
+  StructuredData::DictionarySP GetCapabilities() override;
+
   Status Launch() override;
 
   Status Resume() override;