[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

1 files changed, 9 insertions, 8 deletions

diff --git a/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp b/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
index 82be85699b2..91a60b17fc9 100644
--- a/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
+++ b/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
@@ -70,7 +70,7 @@ SystemRuntime *SystemRuntimeMacOSX::CreateInstance(Process *process) {
 
   if (create)
     return new SystemRuntimeMacOSX(process);
-  return NULL;
+  return nullptr;
 }
 
 // Constructor
@@ -106,7 +106,7 @@ void SystemRuntimeMacOSX::Clear(bool clear_process) {
     m_process->ClearBreakpointSiteByID(m_break_id);
 
   if (clear_process)
-    m_process = NULL;
+    m_process = nullptr;
   m_break_id = LLDB_INVALID_BREAK_ID;
 }
 
@@ -266,7 +266,7 @@ void SystemRuntimeMacOSX::ReadLibdispatchOffsetsAddress() {
 
   static ConstString g_dispatch_queue_offsets_symbol_name(
       "dispatch_queue_offsets");
-  const Symbol *dispatch_queue_offsets_symbol = NULL;
+  const Symbol *dispatch_queue_offsets_symbol = nullptr;
 
   // libdispatch symbols were in libSystem.B.dylib up through Mac OS X 10.6
   // ("Snow Leopard")
@@ -279,7 +279,7 @@ void SystemRuntimeMacOSX::ReadLibdispatchOffsetsAddress() {
 
   // libdispatch symbols are in their own dylib as of Mac OS X 10.7 ("Lion")
   // and later
-  if (dispatch_queue_offsets_symbol == NULL) {
+  if (dispatch_queue_offsets_symbol == nullptr) {
     ModuleSpec libdispatch_module_spec(FileSpec("libdispatch.dylib"));
     module_sp = m_process->GetTarget().GetImages().FindFirstModule(
         libdispatch_module_spec);
@@ -322,7 +322,7 @@ void SystemRuntimeMacOSX::ReadLibpthreadOffsetsAddress() {
 
   static ConstString g_libpthread_layout_offsets_symbol_name(
       "pthread_layout_offsets");
-  const Symbol *libpthread_layout_offsets_symbol = NULL;
+  const Symbol *libpthread_layout_offsets_symbol = nullptr;
 
   ModuleSpec libpthread_module_spec(FileSpec("libsystem_pthread.dylib"));
   ModuleSP module_sp(m_process->GetTarget().GetImages().FindFirstModule(
@@ -370,7 +370,7 @@ void SystemRuntimeMacOSX::ReadLibdispatchTSDIndexesAddress() {
 
   static ConstString g_libdispatch_tsd_indexes_symbol_name(
       "dispatch_tsd_indexes");
-  const Symbol *libdispatch_tsd_indexes_symbol = NULL;
+  const Symbol *libdispatch_tsd_indexes_symbol = nullptr;
 
   ModuleSpec libpthread_module_spec(FileSpec("libdispatch.dylib"));
   ModuleSP module_sp(m_process->GetTarget().GetImages().FindFirstModule(
@@ -726,7 +726,8 @@ void SystemRuntimeMacOSX::PopulateQueueList(
   for (ThreadSP thread_sp : m_process->Threads()) {
     if (thread_sp->GetAssociatedWithLibdispatchQueue() != eLazyBoolNo) {
       if (thread_sp->GetQueueID() != LLDB_INVALID_QUEUE_ID) {
-        if (queue_list.FindQueueByID(thread_sp->GetQueueID()).get() == NULL) {
+        if (queue_list.FindQueueByID(thread_sp->GetQueueID()).get() ==
+            nullptr) {
           QueueSP queue_sp(new Queue(m_process->shared_from_this(),
                                      thread_sp->GetQueueID(),
                                      thread_sp->GetQueueName()));
@@ -933,7 +934,7 @@ void SystemRuntimeMacOSX::PopulateQueuesUsingLibBTR(
       offset = start_of_this_item +
                m_lib_backtrace_recording_info.queue_info_data_offset;
       const char *queue_label = extractor.GetCStr(&offset);
-      if (queue_label == NULL)
+      if (queue_label == nullptr)
         queue_label = "";
 
       offset_t start_of_next_item = start_of_this_item + offset_to_next;