[stable/21.x] Cherry-pick remote address commits

lldb/include/lldb/Symbol/SymbolFile.h

@@ -387,6 +387,15 @@ class SymbolFile : public PluginInterface {
   /// for this module have been changed.
   virtual void SectionFileAddressesChanged() = 0;
 
+  /// Looks for the compile option specified by \p option, and sets \p value to
+  /// it's value. For example, for a flag such as -foo=bar, looking up \p option
+  /// "-foo" will set \p value to "bar". For a standalone flag such as -baz, \p
+  /// value will be empty.
+  ///
+  /// If \p cu is set, only that compile unit is searched. Otherwise, every
+  /// compile unit is searched until the option is found or failure.
+  ///
+  /// Returns true if the option is found.
   virtual bool GetCompileOption(const char *option, std::string &value,
                                 CompileUnit *cu = nullptr) {
     value.clear();

lldb/include/lldb/Target/Target.h

@@ -1204,11 +1204,14 @@ class Target : public std::enable_shared_from_this<Target>,
   // 2 - if there is a process, then read from memory
   // 3 - if there is no process, then read from the file cache
   //
+  // The optional did_read_live_memory parameter will be set true if live memory
+  // was read successfully.
+  //
   // The method is virtual for mocking in the unit tests.
   virtual size_t ReadMemory(const Address &addr, void *dst, size_t dst_len,
                             Status &error, bool force_live_memory = false,
-                            lldb::addr_t *load_addr_ptr = nullptr);
-
+                            lldb::addr_t *load_addr_ptr = nullptr,
+                            bool *did_read_live_memory = nullptr);
   size_t ReadCStringFromMemory(const Address &addr, std::string &out_str,
                                Status &error, bool force_live_memory = false);
 

lldb/source/Plugins/ExpressionParser/Swift/SwiftExpressionParser.cpp

@@ -358,12 +358,12 @@ class LLDBExprNameLookup : public LLDBNameLookup {
   swift::Identifier getPreferredPrivateDiscriminator() override {
     if (m_sc.comp_unit) {
       if (lldb_private::Module *module = m_sc.module_sp.get()) {
-        if (lldb_private::SymbolFile *symbol_file =
-                module->GetSymbolFile()) {
+        if (lldb_private::SymbolFile *symbol_file = module->GetSymbolFile()) {
           std::string private_discriminator_string;
           if (symbol_file->GetCompileOption("-private-discriminator",
-                                              private_discriminator_string,
-                                              m_sc.comp_unit)) {
+                                            private_discriminator_string,
+                                            m_sc.comp_unit) &&
+              !private_discriminator_string.empty()) {
             return m_source_file.getASTContext().getIdentifier(
                 private_discriminator_string);
           }