Fix more functions in Args to use StringRef.

This patch also marks the const char* versions as =delete to prevent
their use.  This has the potential to cause build breakages on some
platforms which I can't compile.  I have tested on Windows, Linux,
and OSX.  Best practices for fixing broken callsites are outlined in
Args.h in a comment above the deleted function declarations.

Eventually we can remove these =delete declarations, but for now they
are important to make sure that all implicit conversions from
const char * are manually audited to make sure that they do not invoke a
conversion from nullptr.

llvm-svn: 281919

32 files changed, 147 insertions, 135 deletions

diff --git a/lldb/source/API/SBPlatform.cpp b/lldb/source/API/SBPlatform.cpp
index 10b7219eb35..6085cef3206 100644
--- a/lldb/source/API/SBPlatform.cpp
+++ b/lldb/source/API/SBPlatform.cpp
@@ -251,7 +251,8 @@ SBError SBPlatform::ConnectRemote(SBPlatformConnectOptions &connect_options) {
   PlatformSP platform_sp(GetSP());
   if (platform_sp && connect_options.GetURL()) {
     Args args;
-    args.AppendArgument(connect_options.GetURL());
+    args.AppendArgument(
+        llvm::StringRef::withNullAsEmpty(connect_options.GetURL()));
     sb_error.ref() = platform_sp->ConnectRemote(args);
   } else {
     sb_error.SetErrorString("invalid platform");
diff --git a/lldb/source/Breakpoint/BreakpointIDList.cpp b/lldb/source/Breakpoint/BreakpointIDList.cpp
index 0c5ff82082b..d7bf191b2e7 100644
--- a/lldb/source/Breakpoint/BreakpointIDList.cpp
+++ b/lldb/source/Breakpoint/BreakpointIDList.cpp
@@ -215,7 +215,7 @@ void BreakpointIDList::FindAndReplaceIDRanges(Args &old_args, Target *target,
             StreamString canonical_id_str;
             BreakpointID::GetCanonicalReference(&canonical_id_str, bp_id,
                                                 bp_loc->GetID());
-            new_args.AppendArgument(canonical_id_str.GetData());
+            new_args.AppendArgument(canonical_id_str.GetString());
           }
         }
       }
@@ -309,7 +309,7 @@ void BreakpointIDList::FindAndReplaceIDRanges(Args &old_args, Target *target,
               StreamString canonical_id_str;
               BreakpointID::GetCanonicalReference(&canonical_id_str, cur_bp_id,
                                                   bp_loc->GetID());
-              new_args.AppendArgument(canonical_id_str.GetData());
+              new_args.AppendArgument(canonical_id_str.GetString());
             }
           }
         } else if ((cur_bp_id == end_bp_id) &&
@@ -321,19 +321,19 @@ void BreakpointIDList::FindAndReplaceIDRanges(Args &old_args, Target *target,
               StreamString canonical_id_str;
               BreakpointID::GetCanonicalReference(&canonical_id_str, cur_bp_id,
                                                   bp_loc->GetID());
-              new_args.AppendArgument(canonical_id_str.GetData());
+              new_args.AppendArgument(canonical_id_str.GetString());
             }
           }
         } else {
           StreamString canonical_id_str;
           BreakpointID::GetCanonicalReference(&canonical_id_str, cur_bp_id,
                                               LLDB_INVALID_BREAK_ID);
-          new_args.AppendArgument(canonical_id_str.GetData());
+          new_args.AppendArgument(canonical_id_str.GetString());
         }
       }
     } else // else is_range was false
     {
-      new_args.AppendArgument(current_arg);
+      new_args.AppendArgument(llvm::StringRef::withNullAsEmpty(current_arg));
     }
   }
 
@@ -345,7 +345,7 @@ void BreakpointIDList::FindAndReplaceIDRanges(Args &old_args, Target *target,
           StreamString canonical_id_str;
           BreakpointID::GetCanonicalReference(
               &canonical_id_str, bkpt_sp->GetID(), LLDB_INVALID_BREAK_ID);
-          new_args.AppendArgument(canonical_id_str.GetData());
+          new_args.AppendArgument(canonical_id_str.GetString());
         }
       }
     }
diff --git a/lldb/source/Commands/CommandObjectBreakpoint.cpp b/lldb/source/Commands/CommandObjectBreakpoint.cpp
index 682e26bbbb4..bab8ecbf0ab 100644
--- a/lldb/source/Commands/CommandObjectBreakpoint.cpp
+++ b/lldb/source/Commands/CommandObjectBreakpoint.cpp
@@ -172,7 +172,7 @@ public:
 
       case 'h': {
         bool success;
-        m_catch_bp = Args::StringToBoolean(option_arg, true, &success);
+        m_catch_bp = Args::StringToBoolean(option_strref, true, &success);
         if (!success)
           error.SetErrorStringWithFormat(
               "Invalid boolean value for on-catch option: '%s'", option_arg);
@@ -192,7 +192,7 @@ public:
       case 'K': {
         bool success;
         bool value;
-        value = Args::StringToBoolean(option_arg, true, &success);
+        value = Args::StringToBoolean(option_strref, true, &success);
         if (value)
           m_skip_prologue = eLazyBoolYes;
         else
@@ -223,7 +223,7 @@ public:
       case 'm': {
         bool success;
         bool value;
-        value = Args::StringToBoolean(option_arg, true, &success);
+        value = Args::StringToBoolean(option_strref, true, &success);
         if (value)
           m_move_to_nearest_code = eLazyBoolYes;
         else
@@ -265,8 +265,8 @@ public:
         break;
 
       case 'O':
-        m_exception_extra_args.AppendArgument("-O");
-        m_exception_extra_args.AppendArgument(option_arg);
+        m_exception_extra_args.AppendArgument(llvm::StringRef("-O"));
+        m_exception_extra_args.AppendArgument(option_strref);
         break;
 
       case 'p':
@@ -304,7 +304,7 @@ public:
 
       case 'w': {
         bool success;
-        m_throw_bp = Args::StringToBoolean(option_arg, true, &success);
+        m_throw_bp = Args::StringToBoolean(option_strref, true, &success);
         if (!success)
           error.SetErrorStringWithFormat(
               "Invalid boolean value for on-throw option: '%s'", option_arg);
@@ -861,7 +861,8 @@ public:
         break;
       case 'o': {
         bool value, success;
-        value = Args::StringToBoolean(option_arg, false, &success);
+        value = Args::StringToBoolean(
+            llvm::StringRef::withNullAsEmpty(option_arg), false, &success);
         if (success) {
           m_one_shot_passed = true;
           m_one_shot = value;
diff --git a/lldb/source/Commands/CommandObjectBreakpointCommand.cpp b/lldb/source/Commands/CommandObjectBreakpointCommand.cpp
index bf758b93ae5..ed10a2454cc 100644
--- a/lldb/source/Commands/CommandObjectBreakpointCommand.cpp
+++ b/lldb/source/Commands/CommandObjectBreakpointCommand.cpp
@@ -268,6 +268,7 @@ are no syntax errors may indicate that a function was declared but never called.
                          ExecutionContext *execution_context) override {
       Error error;
       const int short_option = m_getopt_table[option_idx].val;
+      auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
 
       switch (short_option) {
       case 'o':
@@ -290,7 +291,7 @@ are no syntax errors may indicate that a function was declared but never called.
 
       case 'e': {
         bool success = false;
-        m_stop_on_error = Args::StringToBoolean(option_arg, false, &success);
+        m_stop_on_error = Args::StringToBoolean(option_strref, false, &success);
         if (!success)
           error.SetErrorStringWithFormat(
               "invalid value for stop-on-error: \"%s\"", option_arg);
diff --git a/lldb/source/Commands/CommandObjectExpression.cpp b/lldb/source/Commands/CommandObjectExpression.cpp
index be4f54616c5..cc1fdf44b12 100644
--- a/lldb/source/Commands/CommandObjectExpression.cpp
+++ b/lldb/source/Commands/CommandObjectExpression.cpp
@@ -78,6 +78,7 @@ Error CommandObjectExpression::CommandOptions::SetOptionValue(
     ExecutionContext *execution_context) {
   Error error;
 
+  auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
   const int short_option = g_option_table[option_idx].short_option;
 
   switch (short_option) {
@@ -91,7 +92,7 @@ Error CommandObjectExpression::CommandOptions::SetOptionValue(
   case 'a': {
     bool success;
     bool result;
-    result = Args::StringToBoolean(option_arg, true, &success);
+    result = Args::StringToBoolean(option_strref, true, &success);
     if (!success)
       error.SetErrorStringWithFormat(
           "invalid all-threads value setting: \"%s\"", option_arg);
@@ -101,7 +102,7 @@ Error CommandObjectExpression::CommandOptions::SetOptionValue(
 
   case 'i': {
     bool success;
-    bool tmp_value = Args::StringToBoolean(option_arg, true, &success);
+    bool tmp_value = Args::StringToBoolean(option_strref, true, &success);
     if (success)
       ignore_breakpoints = tmp_value;
     else
@@ -112,7 +113,7 @@ Error CommandObjectExpression::CommandOptions::SetOptionValue(
 
   case 'j': {
     bool success;
-    bool tmp_value = Args::StringToBoolean(option_arg, true, &success);
+    bool tmp_value = Args::StringToBoolean(option_strref, true, &success);
     if (success)
       allow_jit = tmp_value;
     else
@@ -134,7 +135,7 @@ Error CommandObjectExpression::CommandOptions::SetOptionValue(
 
   case 'u': {
     bool success;
-    bool tmp_value = Args::StringToBoolean(option_arg, true, &success);
+    bool tmp_value = Args::StringToBoolean(option_strref, true, &success);
     if (success)
       unwind_on_error = tmp_value;
     else
@@ -168,7 +169,7 @@ Error CommandObjectExpression::CommandOptions::SetOptionValue(
 
   case 'X': {
     bool success;
-    bool tmp_value = Args::StringToBoolean(option_arg, true, &success);
+    bool tmp_value = Args::StringToBoolean(option_strref, true, &success);
     if (success)
       auto_apply_fixits = tmp_value ? eLazyBoolYes : eLazyBoolNo;
     else
diff --git a/lldb/source/Commands/CommandObjectLog.cpp b/lldb/source/Commands/CommandObjectLog.cpp
index e4c5a8656ed..85134442213 100644
--- a/lldb/source/Commands/CommandObjectLog.cpp
+++ b/lldb/source/Commands/CommandObjectLog.cpp
@@ -387,8 +387,9 @@ protected:
       }
       if (strcasecmp(sub_command, "increment") == 0) {
         bool success;
-        bool increment =
-            Args::StringToBoolean(args.GetArgumentAtIndex(1), false, &success);
+        bool increment = Args::StringToBoolean(
+            llvm::StringRef::withNullAsEmpty(args.GetArgumentAtIndex(1)), false,
+            &success);
         if (success) {
           Timer::SetQuiet(!increment);
           result.SetStatus(eReturnStatusSuccessFinishNoResult);
diff --git a/lldb/source/Commands/CommandObjectMemory.cpp b/lldb/source/Commands/CommandObjectMemory.cpp
index 54dfdd1ecef..9a2180c5ed4 100644
--- a/lldb/source/Commands/CommandObjectMemory.cpp
+++ b/lldb/source/Commands/CommandObjectMemory.cpp
@@ -1478,7 +1478,8 @@ protected:
         break;
 
       case eFormatBoolean:
-        uval64 = Args::StringToBoolean(value_str, false, &success);
+        uval64 = Args::StringToBoolean(
+            llvm::StringRef::withNullAsEmpty(value_str), false, &success);
         if (!success) {
           result.AppendErrorWithFormat(
               "'%s' is not a valid boolean string value.\n", value_str);
diff --git a/lldb/source/Commands/CommandObjectMultiword.cpp b/lldb/source/Commands/CommandObjectMultiword.cpp
index dd60af0fc79..80d64193e64 100644
--- a/lldb/source/Commands/CommandObjectMultiword.cpp
+++ b/lldb/source/Commands/CommandObjectMultiword.cpp
@@ -210,7 +210,7 @@ int CommandObjectMultiword::HandleCompletion(Args &input, int &cursor_index,
           matches.DeleteStringAtIndex(0);
           input.Shift();
           cursor_char_position = 0;
-          input.AppendArgument("");
+          input.AppendArgument(llvm::StringRef());
           return cmd_obj->HandleCompletion(
               input, cursor_index, cursor_char_position, match_start_point,
               max_return_elements, word_complete, matches);
diff --git a/lldb/source/Commands/CommandObjectPlatform.cpp b/lldb/source/Commands/CommandObjectPlatform.cpp
index 1a981ce49ea..295f4c7133c 100644
--- a/lldb/source/Commands/CommandObjectPlatform.cpp
+++ b/lldb/source/Commands/CommandObjectPlatform.cpp
@@ -29,6 +29,8 @@
 #include "lldb/Target/Process.h"
 #include "lldb/Utility/Utils.h"
 
+#include "llvm/ADT/SmallString.h"
+
 using namespace lldb;
 using namespace lldb_private;
 
@@ -1057,9 +1059,9 @@ protected:
       Module *exe_module = target->GetExecutableModulePointer();
       if (exe_module) {
         m_options.launch_info.GetExecutableFile() = exe_module->GetFileSpec();
-        char exe_path[PATH_MAX];
-        if (m_options.launch_info.GetExecutableFile().GetPath(exe_path,
-                                                              sizeof(exe_path)))
+        llvm::SmallString<PATH_MAX> exe_path;
+        m_options.launch_info.GetExecutableFile().GetPath(exe_path);
+        if (!exe_path.empty())
           m_options.launch_info.GetArguments().AppendArgument(exe_path);
         m_options.launch_info.GetArchitecture() = exe_module->GetArchitecture();
       }
diff --git a/lldb/source/Commands/CommandObjectProcess.cpp b/lldb/source/Commands/CommandObjectProcess.cpp
index 77305fcef1a..26e7602493d 100644
--- a/lldb/source/Commands/CommandObjectProcess.cpp
+++ b/lldb/source/Commands/CommandObjectProcess.cpp
@@ -212,7 +212,7 @@ protected:
 
     if (target_settings_argv0) {
       m_options.launch_info.GetArguments().AppendArgument(
-          target_settings_argv0);
+          llvm::StringRef(target_settings_argv0));
       m_options.launch_info.SetExecutableFile(
           exe_module_sp->GetPlatformFileSpec(), false);
     } else {
@@ -760,12 +760,13 @@ public:
                          ExecutionContext *execution_context) override {
       Error error;
       const int short_option = m_getopt_table[option_idx].val;
+      auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
 
       switch (short_option) {
       case 's':
         bool tmp_result;
         bool success;
-        tmp_result = Args::StringToBoolean(option_arg, false, &success);
+        tmp_result = Args::StringToBoolean(option_strref, false, &success);
         if (!success)
           error.SetErrorStringWithFormat("invalid boolean option: \"%s\"",
                                          option_arg);
@@ -1458,7 +1459,7 @@ public:
   bool VerifyCommandOptionValue(const std::string &option, int &real_value) {
     bool okay = true;
     bool success = false;
-    bool tmp_value = Args::StringToBoolean(option.c_str(), false, &success);
+    bool tmp_value = Args::StringToBoolean(option, false, &success);
 
     if (success && tmp_value)
       real_value = 1;
diff --git a/lldb/source/Commands/CommandObjectThread.cpp b/lldb/source/Commands/CommandObjectThread.cpp
index f2f7cdc212a..6cefa6ee003 100644
--- a/lldb/source/Commands/CommandObjectThread.cpp
+++ b/lldb/source/Commands/CommandObjectThread.cpp
@@ -157,6 +157,7 @@ public:
                          ExecutionContext *execution_context) override {
       Error error;
       const int short_option = m_getopt_table[option_idx].val;
+      auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
 
       switch (short_option) {
       case 'c': {
@@ -181,7 +182,7 @@ public:
       case 'e': {
         bool success;
         m_extended_backtrace =
-            Args::StringToBoolean(option_arg, false, &success);
+            Args::StringToBoolean(option_strref, false, &success);
         if (!success)
           error.SetErrorStringWithFormat(
               "invalid boolean value for option '%c'", short_option);
@@ -315,11 +316,13 @@ public:
                          ExecutionContext *execution_context) override {
       Error error;
       const int short_option = m_getopt_table[option_idx].val;
+      auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
 
       switch (short_option) {
       case 'a': {
         bool success;
-        bool avoid_no_debug = Args::StringToBoolean(option_arg, true, &success);
+        bool avoid_no_debug =
+            Args::StringToBoolean(option_strref, true, &success);
         if (!success)
           error.SetErrorStringWithFormat(
               "invalid boolean value for option '%c'", short_option);
@@ -331,7 +334,8 @@ public:
 
       case 'A': {
         bool success;
-        bool avoid_no_debug = Args::StringToBoolean(option_arg, true, &success);
+        bool avoid_no_debug =
+            Args::StringToBoolean(option_strref, true, &success);
         if (!success)
           error.SetErrorStringWithFormat(
               "invalid boolean value for option '%c'", short_option);
@@ -1441,11 +1445,12 @@ public:
                          ExecutionContext *execution_context) override {
       Error error;
       const int short_option = m_getopt_table[option_idx].val;
+      auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
 
       switch (short_option) {
       case 'x': {
         bool success;
-        bool tmp_value = Args::StringToBoolean(option_arg, false, &success);
+        bool tmp_value = Args::StringToBoolean(option_strref, false, &success);
         if (success)
           m_from_expression = tmp_value;
         else {
diff --git a/lldb/source/Commands/CommandObjectType.cpp b/lldb/source/Commands/CommandObjectType.cpp
index 60ff00a0330..358e9c67138 100644
--- a/lldb/source/Commands/CommandObjectType.cpp
+++ b/lldb/source/Commands/CommandObjectType.cpp
@@ -298,7 +298,8 @@ private:
 
       switch (short_option) {
       case 'C':
-        m_cascade = Args::StringToBoolean(option_arg, true, &success);
+        m_cascade = Args::StringToBoolean(
+            llvm::StringRef::withNullAsEmpty(option_arg), true, &success);
         if (!success)
           error.SetErrorStringWithFormat("invalid value for cascade: %s",
                                          option_arg);
@@ -530,7 +531,8 @@ private:
 
       switch (short_option) {
       case 'C':
-        m_cascade = Args::StringToBoolean(option_value, true, &success);
+        m_cascade = Args::StringToBoolean(
+            llvm::StringRef::withNullAsEmpty(option_value), true, &success);
         if (!success)
           error.SetErrorStringWithFormat("invalid value for cascade: %s",
                                          option_value);
@@ -1246,7 +1248,8 @@ Error CommandObjectTypeSummaryAdd::CommandOptions::SetOptionValue(
 
   switch (short_option) {
   case 'C':
-    m_flags.SetCascades(Args::StringToBoolean(option_arg, true, &success));
+    m_flags.SetCascades(Args::StringToBoolean(
+        llvm::StringRef::withNullAsEmpty(option_arg), true, &success));
     if (!success)
       error.SetErrorStringWithFormat("invalid value for cascade: %s",
                                      option_arg);
@@ -2557,7 +2560,8 @@ private:
 
       switch (short_option) {
       case 'C':
-        m_cascade = Args::StringToBoolean(option_arg, true, &success);
+        m_cascade = Args::StringToBoolean(
+            llvm::StringRef::withNullAsEmpty(option_arg), true, &success);
         if (!success)
           error.SetErrorStringWithFormat("invalid value for cascade: %s",
                                          option_arg);
diff --git a/lldb/source/Commands/CommandObjectWatchpointCommand.cpp b/lldb/source/Commands/CommandObjectWatchpointCommand.cpp
index b576ce8b2f8..c67bae015d4 100644
--- a/lldb/source/Commands/CommandObjectWatchpointCommand.cpp
+++ b/lldb/source/Commands/CommandObjectWatchpointCommand.cpp
@@ -318,7 +318,8 @@ are no syntax errors may indicate that a function was declared but never called.
 
       case 'e': {
         bool success = false;
-        m_stop_on_error = Args::StringToBoolean(option_arg, false, &success);
+        m_stop_on_error = Args::StringToBoolean(
+            llvm::StringRef::withNullAsEmpty(option_arg), false, &success);
         if (!success)
           error.SetErrorStringWithFormat(
               "invalid value for stop-on-error: \"%s\"", option_arg);
diff --git a/lldb/source/Host/linux/Host.cpp b/lldb/source/Host/linux/Host.cpp
index ca2084d62e5..8acf4a94e5b 100644
--- a/lldb/source/Host/linux/Host.cpp
+++ b/lldb/source/Host/linux/Host.cpp
@@ -323,7 +323,7 @@ static bool GetProcessAndStatInfo(lldb::pid_t pid,
   char *next_var = (char *)buf_sp->GetBytes();
   char *end_buf = next_var + buf_sp->GetByteSize();
   while (next_var < end_buf && 0 != *next_var) {
-    info_env.AppendArgument(next_var);
+    info_env.AppendArgument(llvm::StringRef(next_var));
     next_var += strlen(next_var) + 1;
   }
 
@@ -340,7 +340,7 @@ static bool GetProcessAndStatInfo(lldb::pid_t pid,
     char *next_arg = cmd + strlen(cmd) + 1;
     end_buf = cmd + buf_sp->GetByteSize();
     while (next_arg < end_buf && 0 != *next_arg) {
-      info_args.AppendArgument(next_arg);
+      info_args.AppendArgument(llvm::StringRef(next_arg));
       next_arg += strlen(next_arg) + 1;
     }
   }
diff --git a/lldb/source/Host/windows/Host.cpp b/lldb/source/Host/windows/Host.cpp
index 9fbea89cb9e..e4a6ebe07f1 100644
--- a/lldb/source/Host/windows/Host.cpp
+++ b/lldb/source/Host/windows/Host.cpp
@@ -273,7 +273,7 @@ Error Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
       if (!str_sp)
         continue;
 
-      launch_info.GetArguments().AppendArgument(str_sp->GetValue().c_str());
+      launch_info.GetArguments().AppendArgument(str_sp->GetValue());
     }
   }
 
diff --git a/lldb/source/Interpreter/Args.cpp b/lldb/source/Interpreter/Args.cpp
index b6a60263e8f..0dd093fe27a 100644
--- a/lldb/source/Interpreter/Args.cpp
+++ b/lldb/source/Interpreter/Args.cpp
@@ -362,23 +362,23 @@ const char *Args::Unshift(const char *arg_cstr, char quote_char) {
 void Args::AppendArguments(const Args &rhs) {
   const size_t rhs_argc = rhs.GetArgumentCount();
   for (size_t i = 0; i < rhs_argc; ++i)
-    AppendArgument(rhs.GetArgumentAtIndex(i),
+    AppendArgument(llvm::StringRef(rhs.GetArgumentAtIndex(i)),
                    rhs.GetArgumentQuoteCharAtIndex(i));
 }
 
 void Args::AppendArguments(const char **argv) {
   if (argv) {
     for (uint32_t i = 0; argv[i]; ++i)
-      AppendArgument(argv[i]);
+      AppendArgument(llvm::StringRef::withNullAsEmpty(argv[i]));
   }
 }
 
-const char *Args::AppendArgument(const char *arg_cstr, char quote_char) {
-  return InsertArgumentAtIndex(GetArgumentCount(), arg_cstr, quote_char);
+llvm::StringRef Args::AppendArgument(llvm::StringRef arg_str, char quote_char) {
+  return InsertArgumentAtIndex(GetArgumentCount(), arg_str, quote_char);
 }
 
-const char *Args::InsertArgumentAtIndex(size_t idx, const char *arg_cstr,
-                                        char quote_char) {
+llvm::StringRef Args::InsertArgumentAtIndex(size_t idx, llvm::StringRef arg_str,
+                                            char quote_char) {
   // Since we are using a std::list to hold onto the copied C string and
   // we don't have direct access to the elements, we have to iterate to
   // find the value.
@@ -387,7 +387,7 @@ const char *Args::InsertArgumentAtIndex(size_t idx, const char *arg_cstr,
   for (pos = m_args.begin(); i > 0 && pos != end; ++pos)
     --i;
 
-  pos = m_args.insert(pos, arg_cstr);
+  pos = m_args.insert(pos, arg_str);
 
   if (idx >= m_args_quote_char.size()) {
     m_args_quote_char.resize(idx + 1);
@@ -399,8 +399,9 @@ const char *Args::InsertArgumentAtIndex(size_t idx, const char *arg_cstr,
   return GetArgumentAtIndex(idx);
 }
 
-const char *Args::ReplaceArgumentAtIndex(size_t idx, const char *arg_cstr,
-                                         char quote_char) {
+llvm::StringRef Args::ReplaceArgumentAtIndex(size_t idx,
+                                             llvm::StringRef arg_str,
+                                             char quote_char) {
   // Since we are using a std::list to hold onto the copied C string and
   // we don't have direct access to the elements, we have to iterate to
   // find the value.
@@ -410,7 +411,7 @@ const char *Args::ReplaceArgumentAtIndex(size_t idx, const char *arg_cstr,
     --i;
 
   if (pos != end) {
-    pos->assign(arg_cstr);
+    pos->assign(arg_str);
     assert(idx < m_argv.size() - 1);
     m_argv[idx] = pos->c_str();
     if (idx >= m_args_quote_char.size())
@@ -732,11 +733,6 @@ const char *Args::StripSpaces(std::string &s, bool leading, bool trailing,
   return s.c_str();
 }
 
-bool Args::StringToBoolean(const char *s, bool fail_value,
-  bool *success_ptr) {
-  return StringToBoolean(llvm::StringRef(s ? s : ""), fail_value, success_ptr);
-}
-
 bool Args::StringToBoolean(llvm::StringRef ref, bool fail_value,
                            bool *success_ptr) {
   if (success_ptr)
@@ -915,13 +911,6 @@ Error Args::StringToFormat(const char *s, lldb::Format &format,
   return error;
 }
 
-lldb::Encoding Args::StringToEncoding(const char *s,
-                                      lldb::Encoding fail_value) {
-  if (!s)
-    return fail_value;
-  return StringToEncoding(llvm::StringRef(s), fail_value);
-}
-
 lldb::Encoding Args::StringToEncoding(llvm::StringRef s,
                                       lldb::Encoding fail_value) {
   return llvm::StringSwitch<lldb::Encoding>(s)
@@ -932,12 +921,6 @@ lldb::Encoding Args::StringToEncoding(llvm::StringRef s,
       .Default(fail_value);
 }
 
-uint32_t Args::StringToGenericRegister(const char *s) {
-  if (!s)
-    return LLDB_INVALID_REGNUM;
-  return StringToGenericRegister(llvm::StringRef(s));
-}
-
 uint32_t Args::StringToGenericRegister(llvm::StringRef s) {
   if (s.empty())
     return LLDB_INVALID_REGNUM;
@@ -1015,13 +998,13 @@ void Args::AddOrReplaceEnvironmentVariable(const char *env_var_name,
 
     // Check if the name matches the given env_var_name.
     if (strncmp(env_var_name, arg_value, equal_p - arg_value) == 0) {
-      ReplaceArgumentAtIndex(i, stream.GetString().c_str());
+      ReplaceArgumentAtIndex(i, stream.GetString());
       return;
     }
   }
 
   // We didn't find it.  Append it instead.
-  AppendArgument(stream.GetString().c_str());
+  AppendArgument(stream.GetString());
 }
 
 bool Args::ContainsEnvironmentVariable(const char *env_var_name,
@@ -1239,7 +1222,7 @@ void Args::ParseAliasOptions(Options &options, CommandReturnObject &result,
           if (pos != std::string::npos)
             raw_input_string.erase(pos, strlen(tmp_arg));
         }
-        ReplaceArgumentAtIndex(idx, "");
+        ReplaceArgumentAtIndex(idx, llvm::StringRef());
         if ((long_options[long_options_index].definition->option_has_arg !=
              OptionParser::eNoArgument) &&
             (OptionParser::GetOptionArgument() != nullptr) &&
@@ -1252,7 +1235,7 @@ void Args::ParseAliasOptions(Options &options, CommandReturnObject &result,
             if (pos != std::string::npos)
               raw_input_string.erase(pos, strlen(tmp_arg));
           }
-          ReplaceArgumentAtIndex(idx + 1, "");
+          ReplaceArgumentAtIndex(idx + 1, llvm::StringRef());
         }
       }
     }
diff --git a/lldb/source/Interpreter/CommandInterpreter.cpp b/lldb/source/Interpreter/CommandInterpreter.cpp
index 1bc5103793b..32bcca83522 100644
--- a/lldb/source/Interpreter/CommandInterpreter.cpp
+++ b/lldb/source/Interpreter/CommandInterpreter.cpp
@@ -1760,7 +1760,7 @@ int CommandInterpreter::HandleCompletionMatches(
         look_for_subcommand = true;
         num_command_matches = 0;
         matches.DeleteStringAtIndex(0);
-        parsed_line.AppendArgument("");
+        parsed_line.AppendArgument(llvm::StringRef());
         cursor_index++;
         cursor_char_position = 0;
       }
@@ -1842,7 +1842,8 @@ int CommandInterpreter::HandleCompletion(
         partial_parsed_line.GetArgumentAtIndex(cursor_index);
     if (cursor_char_position == 0 ||
         current_elem[cursor_char_position - 1] != ' ') {
-      parsed_line.InsertArgumentAtIndex(cursor_index + 1, "", '\0');
+      parsed_line.InsertArgumentAtIndex(cursor_index + 1, llvm::StringRef(),
+                                        '\0');
       cursor_index++;
       cursor_char_position = 0;
     }
@@ -1987,21 +1988,23 @@ void CommandInterpreter::BuildAliasCommandArgs(CommandObject *alias_cmd_obj,
                                                             // this above, make
                                                             // sure we don't
                                                             // insert it twice
-          new_args.AppendArgument(value.c_str());
+                                                            new_args
+                                                                .AppendArgument(
+                                                                    value);
       } else {
         if (value_type != OptionParser::eOptionalArgument)
-          new_args.AppendArgument(option.c_str());
+          new_args.AppendArgument(option);
         if (value.compare("<no-argument>") != 0) {
           int index = GetOptionArgumentPosition(value.c_str());
           if (index == 0) {
             // value was NOT a positional argument; must be a real value
             if (value_type != OptionParser::eOptionalArgument)
-              new_args.AppendArgument(value.c_str());
+              new_args.AppendArgument(value);
             else {
               char buffer[255];
               ::snprintf(buffer, sizeof(buffer), "%s%s", option.c_str(),
                          value.c_str());
-              new_args.AppendArgument(buffer);
+              new_args.AppendArgument(llvm::StringRef(buffer));
             }
 
           } else if (static_cast<size_t>(index) >=
@@ -2023,12 +2026,13 @@ void CommandInterpreter::BuildAliasCommandArgs(CommandObject *alias_cmd_obj,
             }
 
             if (value_type != OptionParser::eOptionalArgument)
-              new_args.AppendArgument(cmd_args.GetArgumentAtIndex(index));
+              new_args.AppendArgument(llvm::StringRef::withNullAsEmpty(
+                  cmd_args.GetArgumentAtIndex(index)));
             else {
               char buffer[255];
               ::snprintf(buffer, sizeof(buffer), "%s%s", option.c_str(),
                          cmd_args.GetArgumentAtIndex(index));
-              new_args.AppendArgument(buffer);
+              new_args.AppendArgument(llvm::StringRef(buffer));
             }
             used[index] = true;
           }
@@ -2038,7 +2042,8 @@ void CommandInterpreter::BuildAliasCommandArgs(CommandObject *alias_cmd_obj,
 
     for (size_t j = 0; j < cmd_args.GetArgumentCount(); ++j) {
       if (!used[j] && !wants_raw_input)
-        new_args.AppendArgument(cmd_args.GetArgumentAtIndex(j));
+        new_args.AppendArgument(
+            llvm::StringRef(cmd_args.GetArgumentAtIndex(j)));
     }
 
     cmd_args.Clear();
diff --git a/lldb/source/Interpreter/CommandObject.cpp b/lldb/source/Interpreter/CommandObject.cpp
index d42d3c7f111..702939a1110 100644
--- a/lldb/source/Interpreter/CommandObject.cpp
+++ b/lldb/source/Interpreter/CommandObject.cpp
@@ -300,10 +300,9 @@ int CommandObject::HandleCompletion(Args &input, int &cursor_index,
       cursor_index++;
 
       // I stick an element on the end of the input, because if the last element
-      // is
-      // option that requires an argument, getopt_long_only will freak out.
+      // is option that requires an argument, getopt_long_only will freak out.
 
-      input.AppendArgument("<FAKE-VALUE>");
+      input.AppendArgument(llvm::StringRef("<FAKE-VALUE>"));
 
       input.ParseArgsForCompletion(*cur_options, opt_element_vector,
                                    cursor_index);
@@ -1001,7 +1000,8 @@ bool CommandObjectParsed::Execute(const char *args_string,
       const char *tmp_str = cmd_args.GetArgumentAtIndex(i);
       if (tmp_str[0] == '`') // back-quote
         cmd_args.ReplaceArgumentAtIndex(
-            i, m_interpreter.ProcessEmbeddedScriptCommands(tmp_str));
+            i, llvm::StringRef::withNullAsEmpty(
+                   m_interpreter.ProcessEmbeddedScriptCommands(tmp_str)));
     }
 
     if (CheckRequirements(result)) {
diff --git a/lldb/source/Interpreter/OptionGroupValueObjectDisplay.cpp b/lldb/source/Interpreter/OptionGroupValueObjectDisplay.cpp
index 5ce7fb8ed72..e5943925e86 100644
--- a/lldb/source/Interpreter/OptionGroupValueObjectDisplay.cpp
+++ b/lldb/source/Interpreter/OptionGroupValueObjectDisplay.cpp
@@ -85,6 +85,8 @@ Error OptionGroupValueObjectDisplay::SetOptionValue(
   const int short_option = g_option_table[option_idx].short_option;
   bool success = false;
 
+  auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
+
   switch (short_option) {
   case 'd': {
     int32_t result;
@@ -141,13 +143,13 @@ Error OptionGroupValueObjectDisplay::SetOptionValue(
     break;
 
   case 'S':
-    use_synth = Args::StringToBoolean(option_arg, true, &success);
+    use_synth = Args::StringToBoolean(option_strref, true, &success);
     if (!success)
       error.SetErrorStringWithFormat("invalid synthetic-type '%s'", option_arg);
     break;
 
   case 'V':
-    run_validator = Args::StringToBoolean(option_arg, true, &success);
+    run_validator = Args::StringToBoolean(option_strref, true, &success);
     if (!success)
       error.SetErrorStringWithFormat("invalid validate '%s'", option_arg);
     break;
diff --git a/lldb/source/Interpreter/OptionValueBoolean.cpp b/lldb/source/Interpreter/OptionValueBoolean.cpp
index dbbd46ea093..bd988fa5750 100644
--- a/lldb/source/Interpreter/OptionValueBoolean.cpp
+++ b/lldb/source/Interpreter/OptionValueBoolean.cpp
@@ -1,5 +1,4 @@
-//===-- OptionValueBoolean.cpp ------------------------------------*- C++
-//-*-===//
+//===-- OptionValueBoolean.cpp ----------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -48,8 +47,7 @@ Error OptionValueBoolean::SetValueFromString(llvm::StringRef value_str,
   case eVarSetOperationReplace:
   case eVarSetOperationAssign: {
     bool success = false;
-    bool value =
-        Args::StringToBoolean(value_str.str().c_str(), false, &success);
+    bool value = Args::StringToBoolean(value_str, false, &success);
     if (success) {
       m_value_was_set = true;
       m_current_value = value;
diff --git a/lldb/source/Interpreter/OptionValueDictionary.cpp b/lldb/source/Interpreter/OptionValueDictionary.cpp
index cf8715eebb1..da68a686045 100644
--- a/lldb/source/Interpreter/OptionValueDictionary.cpp
+++ b/lldb/source/Interpreter/OptionValueDictionary.cpp
@@ -85,7 +85,7 @@ size_t OptionValueDictionary::GetArgs(Args &args) const {
     StreamString strm;
     strm.Printf("%s=", pos->first.GetCString());
     pos->second->DumpValue(nullptr, strm, eDumpOptionValue | eDumpOptionRaw);
-    args.AppendArgument(strm.GetString().c_str());
+    args.AppendArgument(strm.GetString());
   }
   return args.GetArgumentCount();
 }
diff --git a/lldb/source/Interpreter/Property.cpp b/lldb/source/Interpreter/Property.cpp
index ba859a5398c..a15b985e8bb 100644
--- a/lldb/source/Interpreter/Property.cpp
+++ b/lldb/source/Interpreter/Property.cpp
@@ -54,7 +54,7 @@ Property::Property(const PropertyDefinition &definition)
     // default value.
     if (definition.default_cstr_value)
       m_value_sp.reset(new OptionValueBoolean(Args::StringToBoolean(
-          definition.default_cstr_value, false, nullptr)));
+          llvm::StringRef(definition.default_cstr_value), false, nullptr)));
     else
       m_value_sp.reset(
           new OptionValueBoolean(definition.default_uint_value != 0));
diff --git a/lldb/source/Plugins/Platform/Android/PlatformAndroidRemoteGDBServer.cpp b/lldb/source/Plugins/Platform/Android/PlatformAndroidRemoteGDBServer.cpp
index 239ac578321..9650fb4028c 100644
--- a/lldb/source/Plugins/Platform/Android/PlatformAndroidRemoteGDBServer.cpp
+++ b/lldb/source/Plugins/Platform/Android/PlatformAndroidRemoteGDBServer.cpp
@@ -137,7 +137,7 @@ Error PlatformAndroidRemoteGDBServer::ConnectRemote(Args &args) {
   if (error.Fail())
     return error;
 
-  args.ReplaceArgumentAtIndex(0, connect_url.c_str());
+  args.ReplaceArgumentAtIndex(0, connect_url);
 
   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PLATFORM));
   if (log)
diff --git a/lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp b/lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
index d554ba8b768..f9ff4983598 100644
--- a/lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
+++ b/lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
@@ -1886,7 +1886,7 @@ PlatformDarwin::LaunchProcess(lldb_private::ProcessLaunchInfo &launch_info) {
     // we get os_log and NSLog messages mirrored to the target process
     // stderr.
     if (!env_vars.ContainsEnvironmentVariable("OS_ACTIVITY_DT_MODE"))
-      env_vars.AppendArgument("OS_ACTIVITY_DT_MODE=enable");
+      env_vars.AppendArgument(llvm::StringRef("OS_ACTIVITY_DT_MODE=enable"));
   }
 
   // Let our parent class do the real launching.
diff --git a/lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp b/lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
index dfb60e1ddc9..e609cb96456 100644
--- a/lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
+++ b/lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
@@ -305,8 +305,7 @@ DynamicRegisterInfo::SetRegisterInfo(const StructuredData::Dictionary &dict,
 
     std::string encoding_str;
     if (reg_info_dict->GetValueForKeyAsString("encoding", encoding_str))
-      reg_info.encoding =
-          Args::StringToEncoding(encoding_str.c_str(), eEncodingUint);
+      reg_info.encoding = Args::StringToEncoding(encoding_str, eEncodingUint);
     else
       reg_info_dict->GetValueForKeyAsInteger("encoding", reg_info.encoding,
                                              eEncodingUint);
@@ -337,7 +336,7 @@ DynamicRegisterInfo::SetRegisterInfo(const StructuredData::Dictionary &dict,
     std::string generic_str;
     if (reg_info_dict->GetValueForKeyAsString("generic", generic_str))
       reg_info.kinds[lldb::eRegisterKindGeneric] =
-          Args::StringToGenericRegister(generic_str.c_str());
+          Args::StringToGenericRegister(generic_str);
     else
       reg_info_dict->GetValueForKeyAsInteger(
           "generic", reg_info.kinds[lldb::eRegisterKindGeneric],
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index ef3e75bbf09..14c64f2e514 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -1067,31 +1067,31 @@ Error GDBRemoteCommunication::StartDebugserverProcess(
     char arg_cstr[PATH_MAX];
 
     // Start args with "debugserver /file/path -r --"
-    debugserver_args.AppendArgument(debugserver_path);
+    debugserver_args.AppendArgument(llvm::StringRef(debugserver_path));
 
 #if !defined(__APPLE__)
     // First argument to lldb-server must be mode in which to run.
-    debugserver_args.AppendArgument("gdbserver");
+    debugserver_args.AppendArgument(llvm::StringRef("gdbserver"));
 #endif
 
     // If a url is supplied then use it
     if (url)
-      debugserver_args.AppendArgument(url);
+      debugserver_args.AppendArgument(llvm::StringRef(url));
 
     if (pass_comm_fd >= 0) {
       StreamString fd_arg;
       fd_arg.Printf("--fd=%i", pass_comm_fd);
-      debugserver_args.AppendArgument(fd_arg.GetData());
+      debugserver_args.AppendArgument(fd_arg.GetString());
       // Send "pass_comm_fd" down to the inferior so it can use it to
       // communicate back with this process
       launch_info.AppendDuplicateFileAction(pass_comm_fd, pass_comm_fd);
     }
 
     // use native registers, not the GDB registers
-    debugserver_args.AppendArgument("--native-regs");
+    debugserver_args.AppendArgument(llvm::StringRef("--native-regs"));
 
     if (launch_info.GetLaunchInSeparateProcessGroup()) {
-      debugserver_args.AppendArgument("--setsid");
+      debugserver_args.AppendArgument(llvm::StringRef("--setsid"));
     }
 
     llvm::SmallString<PATH_MAX> named_pipe_path;
@@ -1137,8 +1137,8 @@ Error GDBRemoteCommunication::StartDebugserverProcess(
           return error;
         }
         int write_fd = socket_pipe.GetWriteFileDescriptor();
-        debugserver_args.AppendArgument("--pipe");
-        debugserver_args.AppendArgument(llvm::to_string(write_fd).c_str());
+        debugserver_args.AppendArgument(llvm::StringRef("--pipe"));
+        debugserver_args.AppendArgument(llvm::to_string(write_fd));
         launch_info.AppendCloseFileAction(socket_pipe.GetReadFileDescriptor());
 #endif
       } else {
@@ -1164,8 +1164,8 @@ Error GDBRemoteCommunication::StartDebugserverProcess(
           // Send the host and port down that debugserver and specify an option
           // so that it connects back to the port we are listening to in this
           // process
-          debugserver_args.AppendArgument("--reverse-connect");
-          debugserver_args.AppendArgument(port_cstr);
+          debugserver_args.AppendArgument(llvm::StringRef("--reverse-connect"));
+          debugserver_args.AppendArgument(llvm::StringRef(port_cstr));
           if (port)
             *port = port_;
         } else {
@@ -1182,7 +1182,7 @@ Error GDBRemoteCommunication::StartDebugserverProcess(
     if (env_debugserver_log_file) {
       ::snprintf(arg_cstr, sizeof(arg_cstr), "--log-file=%s",
                  env_debugserver_log_file);
-      debugserver_args.AppendArgument(arg_cstr);
+      debugserver_args.AppendArgument(llvm::StringRef(arg_cstr));
     }
 
 #if defined(__APPLE__)
@@ -1199,7 +1199,7 @@ Error GDBRemoteCommunication::StartDebugserverProcess(
     if (env_debugserver_log_channels) {
       ::snprintf(arg_cstr, sizeof(arg_cstr), "--log-channels=%s",
                  env_debugserver_log_channels);
-      debugserver_args.AppendArgument(arg_cstr);
+      debugserver_args.AppendArgument(llvm::StringRef(arg_cstr));
     }
 #endif
 
@@ -1215,7 +1215,7 @@ Error GDBRemoteCommunication::StartDebugserverProcess(
       has_env_var = extra_arg != nullptr;
 
       if (has_env_var) {
-        debugserver_args.AppendArgument(extra_arg);
+        debugserver_args.AppendArgument(llvm::StringRef(extra_arg));
         if (log)
           log->Printf("GDBRemoteCommunication::%s adding env var %s contents "
                       "to stub command line (%s)",
@@ -1224,7 +1224,7 @@ Error GDBRemoteCommunication::StartDebugserverProcess(
     } while (has_env_var);
 
     if (inferior_args && inferior_args->GetArgumentCount() > 0) {
-      debugserver_args.AppendArgument("--");
+      debugserver_args.AppendArgument(llvm::StringRef("--"));
       debugserver_args.AppendArguments(*inferior_args);
     }
 
@@ -1232,7 +1232,7 @@ Error GDBRemoteCommunication::StartDebugserverProcess(
     StringList env;
     if (Host::GetEnvironment(env)) {
       for (size_t i = 0; i < env.GetSize(); ++i)
-        launch_info.GetEnvironmentEntries().AppendArgument(env[i].c_str());
+        launch_info.GetEnvironmentEntries().AppendArgument(env[i]);
     }
 
     // Close STDIN, STDOUT and STDERR.
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
index 0d7ca3c53e4..9dfb47d1a76 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -946,7 +946,8 @@ GDBRemoteCommunicationServerCommon::Handle_QEnvironment(
   packet.SetFilePos(::strlen("QEnvironment:"));
   const uint32_t bytes_left = packet.GetBytesLeft();
   if (bytes_left > 0) {
-    m_process_launch_info.GetEnvironmentEntries().AppendArgument(packet.Peek());
+    m_process_launch_info.GetEnvironmentEntries().AppendArgument(
+        llvm::StringRef::withNullAsEmpty(packet.Peek()));
     return SendOKResponse();
   }
   return SendErrorResponse(12);
@@ -960,7 +961,7 @@ GDBRemoteCommunicationServerCommon::Handle_QEnvironmentHexEncoded(
   if (bytes_left > 0) {
     std::string str;
     packet.GetHexByteString(str);
-    m_process_launch_info.GetEnvironmentEntries().AppendArgument(str.c_str());
+    m_process_launch_info.GetEnvironmentEntries().AppendArgument(str);
     return SendOKResponse();
   }
   return SendErrorResponse(12);
@@ -1032,8 +1033,7 @@ GDBRemoteCommunicationServerCommon::Handle_A(StringExtractorGDBRemote &packet) {
                 if (arg_idx == 0)
                   m_process_launch_info.GetExecutableFile().SetFile(arg.c_str(),
                                                                     false);
-                m_process_launch_info.GetArguments().AppendArgument(
-                    arg.c_str());
+                m_process_launch_info.GetArguments().AppendArgument(arg);
                 if (log)
                   log->Printf("LLGSPacketHandler::%s added arg %d: \"%s\"",
                               __FUNCTION__, actual_arg_index, arg.c_str());
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index 504aa4f29e2..4230601d993 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -4158,8 +4158,7 @@ bool ParseRegisters(XMLNode feature_node, GdbServerTargetInfo &target_info,
             alt_name.SetString(value);
           } else if (name == "encoding") {
             encoding_set = true;
-            reg_info.encoding =
-                Args::StringToEncoding(value.data(), eEncodingUint);
+            reg_info.encoding = Args::StringToEncoding(value, eEncodingUint);
           } else if (name == "format") {
             format_set = true;
             Format format = eFormatInvalid;
@@ -4198,7 +4197,7 @@ bool ParseRegisters(XMLNode feature_node, GdbServerTargetInfo &target_info,
                 StringConvert::ToUInt32(value.data(), LLDB_INVALID_REGNUM, 0);
           } else if (name == "generic") {
             reg_info.kinds[eRegisterKindGeneric] =
-                Args::StringToGenericRegister(value.data());
+                Args::StringToGenericRegister(value);
           } else if (name == "value_regnums") {
             SplitCommaSeparatedRegisterNumberString(value, value_regs, 0);
           } else if (name == "invalidate_regnums") {
diff --git a/lldb/source/Plugins/StructuredData/DarwinLog/StructuredDataDarwinLog.cpp b/lldb/source/Plugins/StructuredData/DarwinLog/StructuredDataDarwinLog.cpp
index a7fffdbeeba..6d940e84b4f 100644
--- a/lldb/source/Plugins/StructuredData/DarwinLog/StructuredDataDarwinLog.cpp
+++ b/lldb/source/Plugins/StructuredData/DarwinLog/StructuredDataDarwinLog.cpp
@@ -429,6 +429,7 @@ public:
     Error error;
 
     const int short_option = m_getopt_table[option_idx].val;
+    auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
     switch (short_option) {
     case 'a':
       m_include_any_process = true;
@@ -442,7 +443,7 @@ public:
       break;
 
     case 'b':
-      m_broadcast_events = Args::StringToBoolean(option_arg, true, nullptr);
+      m_broadcast_events = Args::StringToBoolean(option_strref, true, nullptr);
       break;
 
     case 'c':
@@ -458,7 +459,7 @@ public:
       break;
 
     case 'e':
-      m_echo_to_stderr = Args::StringToBoolean(option_arg, false, nullptr);
+      m_echo_to_stderr = Args::StringToBoolean(option_strref, false, nullptr);
       break;
 
     case 'f':
@@ -469,12 +470,12 @@ public:
       break;
 
     case 'l':
-      m_live_stream = Args::StringToBoolean(option_arg, false, nullptr);
+      m_live_stream = Args::StringToBoolean(option_strref, false, nullptr);
       break;
 
     case 'n':
       m_filter_fall_through_accepts =
-          Args::StringToBoolean(option_arg, true, nullptr);
+          Args::StringToBoolean(option_strref, true, nullptr);
       break;
 
     case 'r':
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index f370676e73a..7837881fb82 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -416,6 +416,7 @@ Error ProcessLaunchCommandOptions::SetOptionValue(
     ExecutionContext *execution_context) {
   Error error;
   const int short_option = m_getopt_table[option_idx].val;
+  auto option_strref = llvm::StringRef::withNullAsEmpty(option_arg);
 
   switch (short_option) {
   case 's': // Stop at program entry point
@@ -484,7 +485,7 @@ Error ProcessLaunchCommandOptions::SetOptionValue(
   {
     bool success;
     const bool disable_aslr_arg =
-        Args::StringToBoolean(option_arg, true, &success);
+        Args::StringToBoolean(option_strref, true, &success);
     if (success)
       disable_aslr = disable_aslr_arg ? eLazyBoolYes : eLazyBoolNo;
     else
@@ -497,7 +498,8 @@ Error ProcessLaunchCommandOptions::SetOptionValue(
   case 'X': // shell expand args.
   {
     bool success;
-    const bool expand_args = Args::StringToBoolean(option_arg, true, &success);
+    const bool expand_args =
+        Args::StringToBoolean(option_strref, true, &success);
     if (success)
       launch_info.SetShellExpandArguments(expand_args);
     else
@@ -515,7 +517,8 @@ Error ProcessLaunchCommandOptions::SetOptionValue(
     break;
 
   case 'v':
-    launch_info.GetEnvironmentEntries().AppendArgument(option_arg);
+    launch_info.GetEnvironmentEntries().AppendArgument(
+        llvm::StringRef::withNullAsEmpty(option_arg));
     break;
 
   default:
diff --git a/lldb/source/Target/ProcessInfo.cpp b/lldb/source/Target/ProcessInfo.cpp
index be537c1b313..4b02332f4d9 100644
--- a/lldb/source/Target/ProcessInfo.cpp
+++ b/lldb/source/Target/ProcessInfo.cpp
@@ -18,6 +18,8 @@
 #include "lldb/Core/Stream.h"
 #include "lldb/Host/PosixApi.h"
 
+#include "llvm/ADT/SmallString.h"
+
 using namespace lldb;
 using namespace lldb_private;
 
@@ -66,8 +68,9 @@ void ProcessInfo::SetExecutableFile(const FileSpec &exe_file,
   if (exe_file) {
     m_executable = exe_file;
     if (add_exe_file_as_first_arg) {
-      char filename[PATH_MAX];
-      if (exe_file.GetPath(filename, sizeof(filename)))
+      llvm::SmallString<PATH_MAX> filename;
+      exe_file.GetPath(filename);
+      if (!filename.empty())
         m_arguments.InsertArgumentAtIndex(0, filename);
     }
   } else {
diff --git a/lldb/source/Target/ProcessLaunchInfo.cpp b/lldb/source/Target/ProcessLaunchInfo.cpp
index 2f9e95ecc7b..e29c9bcc11b 100644
--- a/lldb/source/Target/ProcessLaunchInfo.cpp
+++ b/lldb/source/Target/ProcessLaunchInfo.cpp
@@ -344,13 +344,13 @@ bool ProcessLaunchInfo::ConvertArgumentsForLaunchingInShell(
         return false;
       Args shell_arguments;
       std::string safe_arg;
-      shell_arguments.AppendArgument(shell_executable.c_str());
+      shell_arguments.AppendArgument(shell_executable);
       const llvm::Triple &triple = GetArchitecture().GetTriple();
       if (triple.getOS() == llvm::Triple::Win32 &&
           !triple.isWindowsCygwinEnvironment())
-        shell_arguments.AppendArgument("/C");
+        shell_arguments.AppendArgument(llvm::StringRef("/C"));
       else
-        shell_arguments.AppendArgument("-c");
+        shell_arguments.AppendArgument(llvm::StringRef("-c"));
 
       StreamString shell_command;
       if (will_debug) {
@@ -428,7 +428,7 @@ bool ProcessLaunchInfo::ConvertArgumentsForLaunchingInShell(
           shell_command.Printf(" %s", arg);
         }
       }
-      shell_arguments.AppendArgument(shell_command.GetString().c_str());
+      shell_arguments.AppendArgument(shell_command.GetString());
       m_executable = m_shell;
       m_arguments = shell_arguments;
       return true;