[LLDB][ROAR] Initial checkin of ROAR JIT plugin.

Summary:
-- Initial commit of ROARJITLoader.
-- Added an API to get location spec. This is can be used by custom
JITLoader to handle HandleBreakpointBySourceLocation.
-- Modifies LLDB to allow external plugins to have access to
internal process state via the public API. This is necessary for some
plugins that should be part of LLDB (because they need access to
internal LLDB state) but for some reason cannot be linked against LLDB.

Test Plan: ninja check-lldb

Rollback Plan:

Reviewers: jpporto, gclayton, #lldb_team, royshi

Reviewed By: jpporto, gclayton

Differential Revision: https://phabricator.intern.facebook.com/D77634915

Tasks: T227178858

Author: Alexander Yermolovich

lldb/include/lldb/Breakpoint/BreakpointResolverFileLine.h

@@ -56,6 +56,9 @@ class BreakpointResolverFileLine : public BreakpointResolver {
   lldb::BreakpointResolverSP
   CopyForBreakpoint(lldb::BreakpointSP &breakpoint) override;
 
+  /// Get the location spec that this resolver is using.
+  const SourceLocationSpec &GetLocationSpec() const { return m_location_spec; }
+
 protected:
   void FilterContexts(SymbolContextList &sc_list);
   void DeduceSourceMapping(const SymbolContextList &sc_list);

lldb/include/lldb/Target/Process.h

@@ -937,6 +937,15 @@ class Process : public std::enable_shared_from_this<Process>,
 
   const lldb::UnixSignalsSP &GetUnixSignals();
 
+  /// Called by LLDB before calling an external plugin that needs access to
+  /// internal process state using the public API.
+  void WillCallExternalPlugin() { m_making_external_plugin_call = true; }
+
+  /// Called by LLDB after a call to an external plugin that needs access to
+  /// internal process state using the public API returns, thus restoring the
+  /// public API behavior to the default.
+  void DoneCallingExternalPlugin() { m_making_external_plugin_call = false; }
+
   //==================================================================
   // Plug-in Process Control Overrides
   //==================================================================
@@ -3271,6 +3280,10 @@ void PruneThreadPlans();
   /// GetExtendedCrashInformation.
   StructuredData::DictionarySP m_crash_info_dict_sp;
 
+  /// Set to true before calling an external plugin that needs access to
+  /// internal process state.
+  bool m_making_external_plugin_call = false;
+
   size_t RemoveBreakpointOpcodesFromBuffer(lldb::addr_t addr, size_t size,
                                            uint8_t *buf) const;
 

lldb/source/Plugins/JITLoader/CMakeLists.txt

@@ -2,3 +2,4 @@ set_property(DIRECTORY PROPERTY LLDB_PLUGIN_KIND JITLoader)
 set_property(DIRECTORY PROPERTY LLDB_TOLERATED_PLUGIN_DEPENDENCIES ObjectFile)
 
 add_subdirectory(GDB)
+add_subdirectory(ROAR)

lldb/source/Plugins/JITLoader/ROAR/CMakeLists.txt

@@ -0,0 +1,28 @@
+lldb_tablegen(JITLoaderROARProperties.inc -gen-lldb-property-defs
+  SOURCE JITLoaderROARProperties.td
+  TARGET LLDBPluginJITLoaderROARPropertiesGen)
+
+lldb_tablegen(JITLoaderROARPropertiesEnum.inc -gen-lldb-property-enum-defs
+  SOURCE JITLoaderROARProperties.td
+  TARGET LLDBPluginJITLoaderROARPropertiesEnumGen)
+
+add_lldb_library(lldbPluginJITLoaderROAR PLUGIN
+  JITLoaderROAR.cpp
+
+  LINK_LIBS
+    lldbBreakpoint
+    lldbCore
+    lldbInterpreter
+    lldbSymbol
+    lldbTarget
+    lldbUtility
+    lldbPluginObjectFileMachO
+  LINK_COMPONENTS
+    Support
+  )
+
+add_dependencies(lldbPluginJITLoaderROAR
+  LLDBPluginJITLoaderROARPropertiesGen
+  LLDBPluginJITLoaderROARPropertiesEnumGen)
+
+target_include_directories(lldbPluginJITLoaderROAR PRIVATE "${CMAKE_SOURCE_DIR}/../roar/include")