[lldb] Call Target::ClearAllLoadedSections even earlier

[labath]

This reapplies #138892, which was reverted in
5fb9dca due to failures on windows.

Windows loads modules from the Process class, and it does that quite
early, and it kinda makes sense which is why I'm moving the clearing
code even earlier.

The original commit message was:

Minidump files contain explicit information about load addresses of
modules, so it can load them itself. This works on other platforms, but
fails on darwin because DynamicLoaderDarwin nukes the loaded module list
on initialization (which happens after the core file plugin has done its
work).

This used to work until #109477, which enabled the dynamic loader
plugins for minidump files in order to get them to provide access to
TLS.

Clearing the load list makes sense, but I think we could do it earlier
in the process, so that both Process and DynamicLoader plugins get a
chance to load modules. This patch does that by calling the function
early in the launch/attach/load core flows.

This fixes TestDynamicValue.py:test_from_core_file on darwin.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Pavel Labath (labath)

Changes

This reapplies #138892, which was reverted in
5fb9dca due to failures on windows.

Windows loads modules from the Process class, and it does that quite
early, and it kinda makes sense which is why I'm moving the clearing
code even earlier.

The original commit message was:

Minidump files contain explicit information about load addresses of
modules, so it can load them itself. This works on other platforms, but
fails on darwin because DynamicLoaderDarwin nukes the loaded module list
on initialization (which happens after the core file plugin has done its
work).

This used to work until #109477, which enabled the dynamic loader
plugins for minidump files in order to get them to provide access to
TLS.

Clearing the load list makes sense, but I think we could do it earlier
in the process, so that both Process and DynamicLoader plugins get a
chance to load modules. This patch does that by calling the function
early in the launch/attach/load core flows.

This fixes TestDynamicValue.py:test_from_core_file on darwin.

---

Full diff: https://github.com/llvm/llvm-project/pull/140228.diff

3 Files Affected:

• (modified) lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp (-1)
• (modified) lldb/source/Target/Process.cpp (+3)
• (modified) lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py (-1)

diff --git a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
index 578ab12268ea3..1270d57423c7b 100644
--- a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
+++ b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
@@ -872,7 +872,6 @@ void DynamicLoaderDarwin::PrivateInitialize(Process *process) {
                StateAsCString(m_process->GetState()));
   Clear(true);
   m_process = process;
-  m_process->GetTarget().ClearAllLoadedSections();
 }
 
 // Member function that gets called when the process state changes.
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index 13ff12b4ff953..c377feec86c16 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -2675,6 +2675,7 @@ Status Process::LaunchPrivate(ProcessLaunchInfo &launch_info, StateType &state,
   m_jit_loaders_up.reset();
   m_system_runtime_up.reset();
   m_os_up.reset();
+  GetTarget().ClearAllLoadedSections();
 
   {
     std::lock_guard<std::mutex> guard(m_process_input_reader_mutex);
@@ -2799,6 +2800,7 @@ Status Process::LaunchPrivate(ProcessLaunchInfo &launch_info, StateType &state,
 }
 
 Status Process::LoadCore() {
+  GetTarget().ClearAllLoadedSections();
   Status error = DoLoadCore();
   if (error.Success()) {
     ListenerSP listener_sp(
@@ -2984,6 +2986,7 @@ Status Process::Attach(ProcessAttachInfo &attach_info) {
   m_jit_loaders_up.reset();
   m_system_runtime_up.reset();
   m_os_up.reset();
+  GetTarget().ClearAllLoadedSections();
 
   lldb::pid_t attach_pid = attach_info.GetProcessID();
   Status error;
diff --git a/lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py b/lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py
index cd95a9ff3fe8c..faa35421ff60b 100644
--- a/lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py
+++ b/lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py
@@ -282,7 +282,6 @@ def test_from_forward_decl(self):
 
     @no_debug_info_test
     @expectedFailureAll(oslist=["windows"], bugnumber="llvm.org/pr24663")
-    @expectedFailureDarwin  # dynamic loader unloads modules
     @expectedFailureAll(archs=["arm"]) # Minidump saving not implemented
     def test_from_core_file(self):
         """Test fetching C++ dynamic values from core files. Specifically, test

[jasonmolenda]

OK.