Create setting to disable LanguageRuntime provided UnwindPlans

[jasonmolenda]

Summary

When developing LanguageRuntime plugin unwind plans, it is sometimes helpful to work with the concrete stacks. This setting allows for that behavior.

Jim, mostly this is a question of the name of the setting, I think. I never know how to name these things, we seem to have a wide variety of setting name styles. I don't know what might be considered better than other possibilities.

[jingham]

This seems okay to me. Putting it in the process is right. We do "disable X" in a bunch of other places when enabled is the default, so that seems right. And I don't think there's much benefit to trying to squeeze the description into fewer letters, since you're either cutting & pasting into a script or using completion anyway.

lldb/include/lldb/Target/Process.h

 //===-- Process.h -----------------------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLDB_TARGET_PROCESS_H
 #define LLDB_TARGET_PROCESS_H
 
 #include "lldb/Host/Config.h"
 
 #include <limits.h>
 
 #include <chrono>
 #include <list>
 #include <memory>
 #include <mutex>
 #include <string>
public:
   FileSpec GetPythonOSPluginPath() const;
   void SetPythonOSPluginPath(const FileSpec &file);
   bool GetIgnoreBreakpointsInExpressions() const;
   void SetIgnoreBreakpointsInExpressions(bool ignore);
   bool GetUnwindOnErrorInExpressions() const;
   void SetUnwindOnErrorInExpressions(bool ignore);
   bool GetStopOnSharedLibraryEvents() const;
   void SetStopOnSharedLibraryEvents(bool stop);
+  bool GetDisableLangRuntimeUnwindPlans() const;
+  void SetDisableLangRuntimeUnwindPlans(bool disable);
   bool GetDetachKeepsStopped() const;
   void SetDetachKeepsStopped(bool keep_stopped);
   bool GetWarningsOptimization() const;
   bool GetWarningsUnsupportedLanguage() const;
   bool GetStopOnExec() const;
   std::chrono::seconds GetUtilityExpressionTimeout() const;
   bool GetOSPluginReportsAllThreads() const;
   void SetOSPluginReportsAllThreads(bool does_report);

lldb/source/Target/LanguageRuntime.cpp

 }
 
 UnwindPlanSP
 LanguageRuntime::GetRuntimeUnwindPlan(Thread &thread, RegisterContext *regctx,
                                       bool &behaves_like_zeroth_frame) {
   ProcessSP process_sp = thread.GetProcess();
   if (!process_sp.get())
     return UnwindPlanSP();
+  if (process_sp->GetDisableLangRuntimeUnwindPlans() == true)
+    return UnwindPlanSP();
   for (const lldb::LanguageType lang_type : Language::GetSupportedLanguages()) {
     if (LanguageRuntime *runtime = process_sp->GetLanguageRuntime(lang_type)) {
       UnwindPlanSP plan_sp = runtime->GetRuntimeUnwindPlan(
           process_sp, regctx, behaves_like_zeroth_frame);
       if (plan_sp.get())
         return plan_sp;
     }
   }

lldb/source/Target/Process.cpp

       nullptr, idx, g_process_properties[idx].default_uint_value != 0);
 }
 
 void ProcessProperties::SetStopOnSharedLibraryEvents(bool stop) {
   const uint32_t idx = ePropertyStopOnSharedLibraryEvents;
   m_collection_sp->SetPropertyAtIndexAsBoolean(nullptr, idx, stop);
 }
 
+bool ProcessProperties::GetDisableLangRuntimeUnwindPlans() const {
+  const uint32_t idx = ePropertyDisableLangRuntimeUnwindPlans;
+  return m_collection_sp->GetPropertyAtIndexAsBoolean(
+      nullptr, idx, g_process_properties[idx].default_uint_value != 0);
+}
+
+void ProcessProperties::SetDisableLangRuntimeUnwindPlans(bool disable) {
+  const uint32_t idx = ePropertyDisableLangRuntimeUnwindPlans;
+  m_collection_sp->SetPropertyAtIndexAsBoolean(nullptr, idx, disable);
+  m_process->Flush();
+}
+
 bool ProcessProperties::GetDetachKeepsStopped() const {
   const uint32_t idx = ePropertyDetachKeepsStopped;
   return m_collection_sp->GetPropertyAtIndexAsBoolean(
       nullptr, idx, g_process_properties[idx].default_uint_value != 0);
 }
 
 void ProcessProperties::SetDetachKeepsStopped(bool stop) {
   const uint32_t idx = ePropertyDetachKeepsStopped;

lldb/source/Target/TargetProperties.td

     Desc<"If true, errors in expression evaluation will unwind the stack back to the state before the call.">;
   def PythonOSPluginPath: Property<"python-os-plugin-path", "FileSpec">,
     DefaultUnsignedValue<1>,
     Desc<"A path to a python OS plug-in module file that contains a OperatingSystemPlugIn class.">;
   def StopOnSharedLibraryEvents: Property<"stop-on-sharedlibrary-events", "Boolean">,
     Global,
     DefaultFalse,
     Desc<"If true, stop when a shared library is loaded or unloaded.">;
+  def DisableLangRuntimeUnwindPlans: Property<"disable-language-runtime-unwindplans", "Boolean">,
+    Global,
+    DefaultFalse,
+    Desc<"If true, LanguageRuntime plugins' UnwindPlans will not be used when backtracing.">;
   def DetachKeepsStopped: Property<"detach-keeps-stopped", "Boolean">,
     Global,
     DefaultFalse,
     Desc<"If true, detach will attempt to keep the process stopped.">;
   def MemCacheLineSize: Property<"memory-cache-line-size", "UInt64">,
     DefaultUnsignedValue<512>,
     Desc<"The memory cache line size">;
   def WarningOptimization: Property<"optimization-warnings", "Boolean">,