[lldb] Clear ModuleList shared modules in SBDebugger::Clear

lldb/include/lldb/API/SBDebugger.h

@@ -319,6 +319,8 @@ class LLDB_API SBDebugger {
 
   bool SetShowInlineDiagnostics(bool);
 
+  bool SetClearSharedModules(bool);
+
   bool SetUseSourceCache(bool use_source_cache);
 
   bool GetUseSourceCache() const;

lldb/include/lldb/Core/Debugger.h

@@ -373,6 +373,10 @@ class Debugger : public std::enable_shared_from_this<Debugger>,
 
   bool SetShowInlineDiagnostics(bool);
 
+  bool GetClearSharedModules() const;
+
+  bool SetClearSharedModules(bool);
+
   bool LoadPlugin(const FileSpec &spec, Status &error);
 
   void RunIOHandlers();

lldb/include/lldb/Core/ModuleList.h

@@ -482,6 +482,9 @@ class ModuleList {
 
   static bool RemoveSharedModuleIfOrphaned(const Module *module_ptr);
 
+  /// Empty global cache of modules to release memory, file locks, etc.
+  static void ClearSharedModules();
+
   /// Applies 'callback' to each module in this ModuleList.
   /// If 'callback' returns false, iteration terminates.
   /// The 'module_sp' passed to 'callback' is guaranteed to

lldb/source/API/SBDebugger.cpp

@@ -1466,6 +1466,12 @@ bool SBDebugger::SetShowInlineDiagnostics(bool value) {
   return (m_opaque_sp ? m_opaque_sp->SetShowInlineDiagnostics(value) : false);
 }
 
+bool SBDebugger::SetClearSharedModules(bool value) {
+  LLDB_INSTRUMENT_VA(this, value);
+
+  return (m_opaque_sp ? m_opaque_sp->SetClearSharedModules(value) : false);
+}
+
 bool SBDebugger::SetUseSourceCache(bool value) {
   LLDB_INSTRUMENT_VA(this, value);
 

lldb/source/Core/CoreProperties.td

@@ -268,4 +268,8 @@ let Definition = "debugger" in {
     Global,
     DefaultFalse,
     Desc<"Controls whether diagnostics can refer directly to the command input, drawing arrows to it. If false, diagnostics will echo the input.">;
+  def ClearSharedModules: Property<"clear-shared-modules", "Boolean">,
+    Global,
+    DefaultFalse,
+    Desc<"Controls whether the debugger clears internal shared modules as it exits.">;
 }

lldb/source/Core/Debugger.cpp

@@ -700,6 +700,17 @@ bool Debugger::SetShowInlineDiagnostics(bool b) {
   return SetPropertyAtIndex(idx, b);
 }
 
+bool Debugger::GetClearSharedModules() const {
+  const uint32_t idx = ePropertyClearSharedModules;
+  return GetPropertyAtIndexAs<bool>(
+      idx, g_debugger_properties[idx].default_uint_value);
+}
+
+bool Debugger::SetClearSharedModules(bool b) {
+  const uint32_t idx = ePropertyClearSharedModules;
+  return SetPropertyAtIndex(idx, b);
+}
+
 #pragma mark Debugger
 
 // const DebuggerPropertiesSP &
@@ -1099,6 +1110,10 @@ void Debugger::Clear() {
         target_sp->Destroy();
       }
     }
+
+    if (GetClearSharedModules())
+      ModuleList::RemoveOrphanSharedModules(/*mandatory=*/true);
+
     m_broadcaster_manager_sp->Clear();
 
     // Close the input file _before_ we close the input read communications

lldb/source/Core/ModuleList.cpp

@@ -782,7 +782,13 @@ lldb::ModuleSP ModuleList::FindSharedModule(const UUID &uuid) {
 }
 
 size_t ModuleList::RemoveOrphanSharedModules(bool mandatory) {
-  return GetSharedModuleList().RemoveOrphans(mandatory);
+  size_t removed = GetSharedModuleList().RemoveOrphans(mandatory);
+  Log *log = GetLog(LLDBLog::Modules);
+  if (log != nullptr) {
+    LLDB_LOGF(log, "removed %lu shared modules, %lu modules remain", removed,
+              GetSharedModuleList().GetSize());
+  }
+  return removed;
 }
 
 Status

lldb/test/API/python_api/debugger/TestDebuggerAPI.py

@@ -294,3 +294,39 @@ def test_version(self):
 
         self.assertEqual(instance_str, class_str)
         self.assertEqual(class_str, property_str)
+
+    def test_default_SetClearSharedModules(self):
+        """Check that that SBDebugger does not clear shared modules by
+        default.
+        """
+        messages = list()
+        self.dbg.SetLoggingCallback(messages.append)
+        self.runCmd("log enable lldb module")
+        self.dbg.Destroy(self.dbg)
+        self.assertFalse(
+            any("removed 0 shared modules, 0 modules remain" in msg for msg in messages)
+        )
+
+    def test_enable_SetClearSharedModules(self):
+        """Check that SetClearSharedModule(true) clears shared module cache."""
+        messages = list()
+        self.dbg.SetLoggingCallback(messages.append)
+        self.dbg.SetClearSharedModules(True)
+        self.runCmd("log enable lldb module")
+        self.dbg.Destroy(self.dbg)
+        self.assertTrue(
+            any("removed 0 shared modules, 0 modules remain" in msg for msg in messages)
+        )
+
+    def test_enable_clear_shared_modules(self):
+        """Check that clear-shared-module setting is equivalent
+        to SetClearSharedModules(true).
+        """
+        messages = list()
+        self.dbg.SetLoggingCallback(messages.append)
+        self.runCmd("settings set clear-shared-modules true")
+        self.runCmd("log enable lldb module")
+        self.dbg.Destroy(self.dbg)
+        self.assertTrue(
+            any("removed 0 shared modules, 0 modules remain" in msg for msg in messages)
+        )