[lldb] NFC modernize codebase with modernize-use-nullptr

Summary:
NFC = [[ https://llvm.org/docs/Lexicon.html#nfc | Non functional change ]]

This commit is the result of modernizing the LLDB codebase by using
`nullptr` instread of `0` or `NULL`. See
https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-nullptr.html
for more information.

This is the command I ran and I to fix and format the code base:

```
run-clang-tidy.py \
	-header-filter='.*' \
	-checks='-*,modernize-use-nullptr' \
	-fix ~/dev/llvm-project/lldb/.* \
	-format \
	-style LLVM \
	-p ~/llvm-builds/debug-ninja-gcc
```

NOTE: There were also changes to `llvm/utils/unittest` but I did not
include them because I felt that maybe this library shall be updated in
isolation somehow.

NOTE: I know this is a rather large commit but it is a nobrainer in most
parts.

Reviewers: martong, espindola, shafik, #lldb, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: arsenm, jvesely, nhaehnle, hiraditya, JDevlieghere, teemperor, rnkovacs, emaste, kubamracek, nemanjai, ki.stfu, javed.absar, arichardson, kbarton, jrtc27, MaskRay, atanasyan, dexonsmith, arphaman, jfb, jsji, jdoerfert, lldb-commits, llvm-commits

Tags: #lldb, #llvm

Differential Revision: https://reviews.llvm.org/D61847

llvm-svn: 361484
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteClientBase.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteClientBase.cpp
index 3bf0f5c..fe7ef6b 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteClientBase.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteClientBase.cpp
@@ -285,7 +285,7 @@
 
 void GDBRemoteClientBase::OnRunPacketSent(bool first) {
   if (first)
-    BroadcastEvent(eBroadcastBitRunPacketSent, NULL);
+    BroadcastEvent(eBroadcastBitRunPacketSent, nullptr);
 }
 
 ///////////////////////////////////////
@@ -365,7 +365,7 @@
       // packet. Let's interrupt it.
       const char ctrl_c = '\x03';
       ConnectionStatus status = eConnectionStatusSuccess;
-      size_t bytes_written = m_comm.Write(&ctrl_c, 1, status, NULL);
+      size_t bytes_written = m_comm.Write(&ctrl_c, 1, status, nullptr);
       if (bytes_written == 0) {
         --m_comm.m_async_count;
         if (log)
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index 31af1cd..9c3a02e 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -98,7 +98,7 @@
   Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS));
   ConnectionStatus status = eConnectionStatusSuccess;
   char ch = '+';
-  const size_t bytes_written = Write(&ch, 1, status, NULL);
+  const size_t bytes_written = Write(&ch, 1, status, nullptr);
   if (log)
     log->Printf("<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch);
   m_history.AddPacket(ch, GDBRemoteCommunicationHistory::ePacketTypeSend,
@@ -110,7 +110,7 @@
   Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS));
   ConnectionStatus status = eConnectionStatusSuccess;
   char ch = '-';
-  const size_t bytes_written = Write(&ch, 1, status, NULL);
+  const size_t bytes_written = Write(&ch, 1, status, nullptr);
   if (log)
     log->Printf("<%4" PRIu64 "> send packet: %c", (uint64_t)bytes_written, ch);
   m_history.AddPacket(ch, GDBRemoteCommunicationHistory::ePacketTypeSend,
@@ -138,7 +138,7 @@
     ConnectionStatus status = eConnectionStatusSuccess;
     const char *packet_data = packet.data();
     const size_t packet_length = packet.size();
-    size_t bytes_written = Write(packet_data, packet_length, status, NULL);
+    size_t bytes_written = Write(packet_data, packet_length, status, nullptr);
     if (log) {
       size_t binary_start_offset = 0;
       if (strncmp(packet_data, "$vFile:pwrite:", strlen("$vFile:pwrite:")) ==
@@ -274,7 +274,7 @@
   Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS));
 
   // Check for a packet from our cache first without trying any reading...
-  if (CheckForPacket(NULL, 0, packet) != PacketType::Invalid)
+  if (CheckForPacket(nullptr, 0, packet) != PacketType::Invalid)
     return PacketResult::Success;
 
   bool timed_out = false;
@@ -470,7 +470,7 @@
       content_length = hash_mark_idx - content_start;
       std::string bufsize_str(m_bytes.data() + 2, i - 2 - 1);
       errno = 0;
-      decompressed_bufsize = ::strtoul(bufsize_str.c_str(), NULL, 10);
+      decompressed_bufsize = ::strtoul(bufsize_str.c_str(), nullptr, 10);
       if (errno != 0 || decompressed_bufsize == ULONG_MAX) {
         m_bytes.erase(0, size_of_first_packet);
         return false;
@@ -483,7 +483,7 @@
     packet_checksum_cstr[0] = m_bytes[checksum_idx];
     packet_checksum_cstr[1] = m_bytes[checksum_idx + 1];
     packet_checksum_cstr[2] = '\0';
-    long packet_checksum = strtol(packet_checksum_cstr, NULL, 16);
+    long packet_checksum = strtol(packet_checksum_cstr, nullptr, 16);
 
     long actual_checksum = CalculcateChecksum(
         llvm::StringRef(m_bytes).substr(1, hash_mark_idx - 1));
@@ -848,7 +848,7 @@
             ::isxdigit(m_bytes[checksum_idx + 1])) {
           if (GetSendAcks()) {
             const char *packet_checksum_cstr = &m_bytes[checksum_idx];
-            char packet_checksum = strtol(packet_checksum_cstr, NULL, 16);
+            char packet_checksum = strtol(packet_checksum_cstr, nullptr, 16);
             char actual_checksum = CalculcateChecksum(
                 llvm::StringRef(m_bytes).slice(content_start, content_end));
             success = packet_checksum == actual_checksum;
@@ -923,9 +923,9 @@
     // Do the listen on another thread so we can continue on...
     if (connection->Connect(comm->m_listen_url.c_str(), &error) !=
         eConnectionStatusSuccess)
-      comm->SetConnection(NULL);
+      comm->SetConnection(nullptr);
   }
-  return NULL;
+  return nullptr;
 }
 
 Status GDBRemoteCommunication::StartDebugserverProcess(
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index c6b792e..9797184 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -386,14 +386,14 @@
         std::vector<std::string> supported_compressions;
         compressions += sizeof("SupportedCompressions=") - 1;
         const char *end_of_compressions = strchr(compressions, ';');
-        if (end_of_compressions == NULL) {
+        if (end_of_compressions == nullptr) {
           end_of_compressions = strchr(compressions, '\0');
         }
         const char *current_compression = compressions;
         while (current_compression < end_of_compressions) {
           const char *next_compression_name = strchr(current_compression, ',');
           const char *end_of_this_word = next_compression_name;
-          if (next_compression_name == NULL ||
+          if (next_compression_name == nullptr ||
               end_of_compressions < next_compression_name) {
             end_of_this_word = end_of_compressions;
           }
@@ -775,7 +775,7 @@
   std::vector<const char *> argv;
   FileSpec exe_file = launch_info.GetExecutableFile();
   std::string exe_path;
-  const char *arg = NULL;
+  const char *arg = nullptr;
   const Args &launch_args = launch_info.GetArguments();
   if (exe_file)
     exe_path = exe_file.GetPath(false);
@@ -786,7 +786,7 @@
   }
   if (!exe_path.empty()) {
     argv.push_back(exe_path.c_str());
-    for (uint32_t i = 1; (arg = launch_args.GetArgumentAtIndex(i)) != NULL;
+    for (uint32_t i = 1; (arg = launch_args.GetArgumentAtIndex(i)) != nullptr;
          ++i) {
       if (arg)
         argv.push_back(arg);
@@ -1094,7 +1094,7 @@
     if (!m_gdb_server_name.empty())
       return m_gdb_server_name.c_str();
   }
-  return NULL;
+  return nullptr;
 }
 
 uint32_t GDBRemoteCommunicationClient::GetGDBServerProgramVersion() {
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
index 56ee0a1..a77e659 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
@@ -98,7 +98,7 @@
 bool GDBRemoteRegisterContext::PrivateSetRegisterValue(
     uint32_t reg, llvm::ArrayRef<uint8_t> data) {
   const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
-  if (reg_info == NULL)
+  if (reg_info == nullptr)
     return false;
 
   // Invalidate if needed
@@ -122,7 +122,7 @@
 bool GDBRemoteRegisterContext::PrivateSetRegisterValue(uint32_t reg,
                                                        uint64_t new_reg_val) {
   const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
-  if (reg_info == NULL)
+  if (reg_info == nullptr)
     return false;
 
   // Early in process startup, we can get a thread that has an invalid byte
@@ -148,7 +148,7 @@
   uint8_t *dst = const_cast<uint8_t *>(
       m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size));
 
-  if (dst == NULL)
+  if (dst == nullptr)
     return false;
 
   if (data.CopyByteOrderedData(0,                          // src offset
@@ -183,7 +183,7 @@
 
   Process *process = exe_ctx.GetProcessPtr();
   Thread *thread = exe_ctx.GetThreadPtr();
-  if (process == NULL || thread == NULL)
+  if (process == nullptr || thread == nullptr)
     return false;
 
   GDBRemoteCommunicationClient &gdb_comm(
@@ -228,7 +228,7 @@
         // We have a valid primordial register as our constituent. Grab the
         // corresponding register info.
         const RegisterInfo *prim_reg_info = GetRegisterInfoAtIndex(prim_reg);
-        if (prim_reg_info == NULL)
+        if (prim_reg_info == nullptr)
           success = false;
         else {
           // Read the containing register if it hasn't already been read
@@ -301,7 +301,7 @@
 
   Process *process = exe_ctx.GetProcessPtr();
   Thread *thread = exe_ctx.GetThreadPtr();
-  if (process == NULL || thread == NULL)
+  if (process == nullptr || thread == nullptr)
     return false;
 
   GDBRemoteCommunicationClient &gdb_comm(
@@ -319,7 +319,7 @@
   uint8_t *dst = const_cast<uint8_t *>(
       m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size));
 
-  if (dst == NULL)
+  if (dst == nullptr)
     return false;
 
   if (data.CopyByteOrderedData(data_offset,                // src offset
@@ -361,7 +361,7 @@
             // We have a valid primordial register as our constituent. Grab the
             // corresponding register info.
             const RegisterInfo *value_reg_info = GetRegisterInfoAtIndex(reg);
-            if (value_reg_info == NULL)
+            if (value_reg_info == nullptr)
               success = false;
             else
               success = SetPrimordialRegister(value_reg_info, gdb_comm);
@@ -409,7 +409,7 @@
 
   Process *process = exe_ctx.GetProcessPtr();
   Thread *thread = exe_ctx.GetThreadPtr();
-  if (process == NULL || thread == NULL)
+  if (process == nullptr || thread == nullptr)
     return false;
 
   GDBRemoteCommunicationClient &gdb_comm(
@@ -434,7 +434,7 @@
 
     Process *process = exe_ctx.GetProcessPtr();
     Thread *thread = exe_ctx.GetThreadPtr();
-    if (process == NULL || thread == NULL)
+    if (process == nullptr || thread == nullptr)
       return false;
 
     GDBRemoteCommunicationClient &gdb_comm(
@@ -452,7 +452,7 @@
 
   Process *process = exe_ctx.GetProcessPtr();
   Thread *thread = exe_ctx.GetThreadPtr();
-  if (process == NULL || thread == NULL)
+  if (process == nullptr || thread == nullptr)
     return false;
 
   GDBRemoteCommunicationClient &gdb_comm(
@@ -474,7 +474,8 @@
     // individually and store them as binary data in a buffer.
     const RegisterInfo *reg_info;
 
-    for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != NULL; i++) {
+    for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != nullptr;
+         i++) {
       if (reg_info
               ->value_regs) // skip registers that are slices of real registers
         continue;
@@ -508,14 +509,14 @@
 
 bool GDBRemoteRegisterContext::WriteAllRegisterValues(
     const lldb::DataBufferSP &data_sp) {
-  if (!data_sp || data_sp->GetBytes() == NULL || data_sp->GetByteSize() == 0)
+  if (!data_sp || data_sp->GetBytes() == nullptr || data_sp->GetByteSize() == 0)
     return false;
 
   ExecutionContext exe_ctx(CalculateThread());
 
   Process *process = exe_ctx.GetProcessPtr();
   Thread *thread = exe_ctx.GetThreadPtr();
-  if (process == NULL || thread == NULL)
+  if (process == nullptr || thread == nullptr)
     return false;
 
   GDBRemoteCommunicationClient &gdb_comm(
@@ -557,9 +558,9 @@
       uint64_t size_by_highest_offset = 0;
 
       for (uint32_t reg_idx = 0;
-           (reg_info = GetRegisterInfoAtIndex(reg_idx)) != NULL; ++reg_idx) {
+           (reg_info = GetRegisterInfoAtIndex(reg_idx)) != nullptr; ++reg_idx) {
         size_including_slice_registers += reg_info->byte_size;
-        if (reg_info->value_regs == NULL)
+        if (reg_info->value_regs == nullptr)
           size_not_including_slice_registers += reg_info->byte_size;
         if (reg_info->byte_offset >= size_by_highest_offset)
           size_by_highest_offset = reg_info->byte_offset + reg_info->byte_size;
@@ -591,7 +592,7 @@
       // keep track of the size of each reg & compute offset based on that.
       uint32_t running_byte_offset = 0;
       for (uint32_t reg_idx = 0;
-           (reg_info = GetRegisterInfoAtIndex(reg_idx)) != NULL;
+           (reg_info = GetRegisterInfoAtIndex(reg_idx)) != nullptr;
            ++reg_idx, running_byte_offset += reg_info->byte_size) {
         // Skip composite aka slice registers (e.g. eax is a slice of rax).
         if (reg_info->value_regs)
@@ -637,7 +638,7 @@
       }
       uint32_t num_restored = 0;
       const RegisterInfo *reg_info;
-      for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != NULL;
+      for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != nullptr;
            i++) {
         if (reg_info->value_regs) // skip registers that are slices of real
                                   // registers
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index db95d91..422b092 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -114,12 +114,12 @@
     {"packet-timeout", OptionValue::eTypeUInt64, true, 5
 #if defined(__has_feature)
 #if __has_feature(address_sanitizer)
-      * 2
+         * 2
 #endif
 #endif
-      , NULL, {},
+     , nullptr, {},
      "Specify the default packet timeout in seconds."},
-    {"target-definition-file", OptionValue::eTypeFileSpec, true, 0, NULL, {},
+    {"target-definition-file", OptionValue::eTypeFileSpec, true, 0, nullptr, {},
      "The file that provides the description for remote target registers."}};
 
 enum { ePropertyPacketTimeout, ePropertyTargetDefinitionFile };
@@ -140,17 +140,17 @@
   uint64_t GetPacketTimeout() {
     const uint32_t idx = ePropertyPacketTimeout;
     return m_collection_sp->GetPropertyAtIndexAsUInt64(
-        NULL, idx, g_properties[idx].default_uint_value);
+        nullptr, idx, g_properties[idx].default_uint_value);
   }
 
   bool SetPacketTimeout(uint64_t timeout) {
     const uint32_t idx = ePropertyPacketTimeout;
-    return m_collection_sp->SetPropertyAtIndexAsUInt64(NULL, idx, timeout);
+    return m_collection_sp->SetPropertyAtIndexAsUInt64(nullptr, idx, timeout);
   }
 
   FileSpec GetTargetDefinitionFile() const {
     const uint32_t idx = ePropertyTargetDefinitionFile;
-    return m_collection_sp->GetPropertyAtIndexAsFileSpec(NULL, idx);
+    return m_collection_sp->GetPropertyAtIndexAsFileSpec(nullptr, idx);
   }
 };
 
@@ -252,7 +252,7 @@
                                  ListenerSP listener_sp,
                                  const FileSpec *crash_file_path) {
   lldb::ProcessSP process_sp;
-  if (crash_file_path == NULL)
+  if (crash_file_path == nullptr)
     process_sp = std::make_shared<ProcessGDBRemote>(target_sp, listener_sp);
   return process_sp;
 }
@@ -294,7 +294,7 @@
     : Process(target_sp, listener_sp),
       m_debugserver_pid(LLDB_INVALID_PROCESS_ID), m_last_stop_packet_mutex(),
       m_register_info(),
-      m_async_broadcaster(NULL, "lldb.process.gdb-remote.async-broadcaster"),
+      m_async_broadcaster(nullptr, "lldb.process.gdb-remote.async-broadcaster"),
       m_async_listener_sp(
           Listener::MakeListener("lldb.process.gdb-remote.async-listener")),
       m_async_thread_state_mutex(), m_thread_ids(), m_thread_pcs(),
@@ -547,8 +547,8 @@
         std::vector<uint32_t> invalidate_regs;
         std::vector<uint8_t> dwarf_opcode_bytes;
         RegisterInfo reg_info = {
-            NULL,          // Name
-            NULL,          // Alt name
+            nullptr,       // Name
+            nullptr,       // Alt name
             0,             // byte size
             reg_offset,    // offset
             eEncodingUint, // encoding
@@ -560,10 +560,10 @@
                 reg_num,             // process plugin reg num
                 reg_num              // native register number
             },
-            NULL,
-            NULL,
-            NULL, // Dwarf expression opcode bytes pointer
-            0     // Dwarf expression opcode bytes length
+            nullptr,
+            nullptr,
+            nullptr, // Dwarf expression opcode bytes pointer
+            0        // Dwarf expression opcode bytes length
         };
 
         while (response.GetNameColonValue(name, value)) {
@@ -583,7 +583,7 @@
               reg_info.encoding = encoding;
           } else if (name.equals("format")) {
             Format format = eFormatInvalid;
-            if (OptionArgParser::ToFormat(value.str().c_str(), format, NULL)
+            if (OptionArgParser::ToFormat(value.str().c_str(), format, nullptr)
                     .Success())
               reg_info.format = format;
             else {
@@ -888,8 +888,8 @@
         // since 'O' packets can really slow down debugging if the inferior
         // does a lot of output.
         if ((!stdin_file_spec || !stdout_file_spec || !stderr_file_spec) &&
-            pty.OpenFirstAvailableMaster(O_RDWR | O_NOCTTY, NULL, 0)) {
-          FileSpec slave_name{pty.GetSlaveName(NULL, 0)};
+            pty.OpenFirstAvailableMaster(O_RDWR | O_NOCTTY, nullptr, 0)) {
+          FileSpec slave_name{pty.GetSlaveName(nullptr, 0)};
 
           if (!stdin_file_spec)
             stdin_file_spec = slave_name;
@@ -933,7 +933,7 @@
           GetTarget().GetArchitecture().GetArchitectureName());
 
       const char *launch_event_data = launch_info.GetLaunchEventData();
-      if (launch_event_data != NULL && *launch_event_data != '\0')
+      if (launch_event_data != nullptr && *launch_event_data != '\0')
         m_gdb_comm.SendLaunchEventDataPacket(launch_event_data);
 
       if (working_dir) {
@@ -1847,7 +1847,7 @@
         gdb_thread->PrivateSetRegisterValue(pair.first, buffer_sp->GetData());
       }
 
-      thread_sp->SetName(thread_name.empty() ? NULL : thread_name.c_str());
+      thread_sp->SetName(thread_name.empty() ? nullptr : thread_name.c_str());
 
       gdb_thread->SetThreadDispatchQAddr(thread_dispatch_qaddr);
       // Check if the GDB server was able to provide the queue name, kind and
@@ -3126,7 +3126,7 @@
                                   Status &error) {
   if (m_stdio_communication.IsConnected()) {
     ConnectionStatus status;
-    m_stdio_communication.Write(src, src_len, status, NULL);
+    m_stdio_communication.Write(src, src_len, status, nullptr);
   } else if (m_stdin_forward) {
     m_gdb_comm.SendStdinNotification(src, src_len);
   }
@@ -3135,7 +3135,7 @@
 
 Status ProcessGDBRemote::EnableBreakpointSite(BreakpointSite *bp_site) {
   Status error;
-  assert(bp_site != NULL);
+  assert(bp_site != nullptr);
 
   // Get logging info
   Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_BREAKPOINTS));
@@ -3261,7 +3261,7 @@
 
 Status ProcessGDBRemote::DisableBreakpointSite(BreakpointSite *bp_site) {
   Status error;
-  assert(bp_site != NULL);
+  assert(bp_site != nullptr);
   addr_t addr = bp_site->GetLoadAddress();
   user_id_t site_id = bp_site->GetID();
   Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_BREAKPOINTS));
@@ -3672,9 +3672,9 @@
     // Create a thread that watches our internal state and controls which
     // events make it to clients (into the DCProcess event queue).
 
-    m_async_thread =
-        ThreadLauncher::LaunchThread("<lldb.process.gdb-remote.async>",
-                                     ProcessGDBRemote::AsyncThread, this, NULL);
+    m_async_thread = ThreadLauncher::LaunchThread(
+        "<lldb.process.gdb-remote.async>", ProcessGDBRemote::AsyncThread, this,
+        nullptr);
   } else if (log)
     log->Printf("ProcessGDBRemote::%s () - Called when Async thread was "
                 "already running.",
@@ -3768,7 +3768,7 @@
                           ") got eBroadcastBitAsyncContinue: %s",
                           __FUNCTION__, arg, process->GetID(), continue_cstr);
 
-            if (::strstr(continue_cstr, "vAttach") == NULL)
+            if (::strstr(continue_cstr, "vAttach") == nullptr)
               process->SetPrivateState(eStateRunning);
             StringExtractorGDBRemote response;
 
@@ -3834,11 +3834,11 @@
                 // the "E87" error code from debugserver -- this indicates that
                 // the process is not debuggable.  Return a slightly more
                 // helpful error message about why the attach failed.
-                if (::strstr(continue_cstr, "vAttach") != NULL &&
+                if (::strstr(continue_cstr, "vAttach") != nullptr &&
                     response.GetError() == 0x87) {
                   process->SetExitStatus(-1, "cannot attach to process due to "
                                              "System Integrity Protection");
-                } else if (::strstr(continue_cstr, "vAttach") != NULL &&
+                } else if (::strstr(continue_cstr, "vAttach") != nullptr &&
                            response.GetStatus().Fail()) {
                   process->SetExitStatus(-1, response.GetStatus().AsCString());
                 } else {
@@ -3913,7 +3913,7 @@
                 ") thread exiting...",
                 __FUNCTION__, arg, process->GetID());
 
-  return NULL;
+  return nullptr;
 }
 
 // uint32_t
@@ -4009,7 +4009,7 @@
       }
     }
   }
-  return m_thread_create_bp_sp.get() != NULL;
+  return m_thread_create_bp_sp.get() != nullptr;
 }
 
 bool ProcessGDBRemote::StopNoticingNewThreads() {
@@ -4024,8 +4024,8 @@
 }
 
 DynamicLoader *ProcessGDBRemote::GetDynamicLoader() {
-  if (m_dyld_up.get() == NULL)
-    m_dyld_up.reset(DynamicLoader::FindPlugin(this, NULL));
+  if (m_dyld_up.get() == nullptr)
+    m_dyld_up.reset(DynamicLoader::FindPlugin(this, nullptr));
   return m_dyld_up.get();
 }
 
@@ -4366,8 +4366,8 @@
         bool encoding_set = false;
         bool format_set = false;
         RegisterInfo reg_info = {
-            NULL,          // Name
-            NULL,          // Alt name
+            nullptr,       // Name
+            nullptr,       // Alt name
             0,             // byte size
             reg_offset,    // offset
             eEncodingUint, // encoding
@@ -4379,10 +4379,10 @@
                 cur_reg_num,         // process plugin reg num
                 cur_reg_num          // native register number
             },
-            NULL,
-            NULL,
-            NULL, // Dwarf Expression opcode bytes pointer
-            0     // Dwarf Expression opcode bytes length
+            nullptr,
+            nullptr,
+            nullptr, // Dwarf Expression opcode bytes pointer
+            0        // Dwarf Expression opcode bytes length
         };
 
         reg_node.ForEachAttribute([&target_info, &gdb_group, &gdb_type,
@@ -4416,7 +4416,8 @@
           } else if (name == "format") {
             format_set = true;
             Format format = eFormatInvalid;
-            if (OptionArgParser::ToFormat(value.data(), format, NULL).Success())
+            if (OptionArgParser::ToFormat(value.data(), format, nullptr)
+                    .Success())
               reg_info.format = format;
             else if (value == "vector-sint8")
               reg_info.format = eFormatVectorOfSInt8;
@@ -5133,7 +5134,7 @@
                             "Tests packet speeds of various sizes to determine "
                             "the performance characteristics of the GDB remote "
                             "connection. ",
-                            NULL),
+                            nullptr),
         m_option_group(),
         m_num_packets(LLDB_OPT_SET_1, false, "count", 'c', 0, eArgTypeCount,
                       "The number of packets to send of each varying size "
@@ -5207,7 +5208,7 @@
 public:
   CommandObjectProcessGDBRemotePacketHistory(CommandInterpreter &interpreter)
       : CommandObjectParsed(interpreter, "process plugin packet history",
-                            "Dumps the packet history buffer. ", NULL) {}
+                            "Dumps the packet history buffer. ", nullptr) {}
 
   ~CommandObjectProcessGDBRemotePacketHistory() override {}
 
@@ -5238,7 +5239,7 @@
       : CommandObjectParsed(
             interpreter, "process plugin packet xfer-size",
             "Maximum size that lldb will try to read/write one one chunk.",
-            NULL) {}
+            nullptr) {}
 
   ~CommandObjectProcessGDBRemotePacketXferSize() override {}
 
@@ -5258,7 +5259,7 @@
     if (process) {
       const char *packet_size = command.GetArgumentAtIndex(0);
       errno = 0;
-      uint64_t user_specified_max = strtoul(packet_size, NULL, 10);
+      uint64_t user_specified_max = strtoul(packet_size, nullptr, 10);
       if (errno == 0 && user_specified_max != 0) {
         process->SetUserSpecifiedMaxMemoryTransferSize(user_specified_max);
         result.SetStatus(eReturnStatusSuccessFinishResult);
@@ -5280,7 +5281,7 @@
                             "The packet header and footer will automatically "
                             "be added to the packet prior to sending and "
                             "stripped from the result.",
-                            NULL) {}
+                            nullptr) {}
 
   ~CommandObjectProcessGDBRemotePacketSend() override {}
 
@@ -5308,7 +5309,7 @@
         output_strm.Printf("  packet: %s\n", packet_cstr);
         std::string &response_str = response.GetStringRef();
 
-        if (strstr(packet_cstr, "qGetProfileData") != NULL) {
+        if (strstr(packet_cstr, "qGetProfileData") != nullptr) {
           response_str = process->HarmonizeThreadIdsForProfileData(response);
         }
 
@@ -5376,7 +5377,7 @@
   CommandObjectProcessGDBRemotePacket(CommandInterpreter &interpreter)
       : CommandObjectMultiword(interpreter, "process plugin packet",
                                "Commands that deal with GDB remote packets.",
-                               NULL) {
+                               nullptr) {
     LoadSubCommand(
         "history",
         CommandObjectSP(