[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, 4 insertions, 4 deletions

diff --git a/lldb/source/Host/common/Host.cpp b/lldb/source/Host/common/Host.cpp
index d3e41a2b044..be206406e93 100644
--- a/lldb/source/Host/common/Host.cpp
+++ b/lldb/source/Host/common/Host.cpp
@@ -112,7 +112,7 @@ HostThread Host::StartMonitoringChildProcess(
   ::snprintf(thread_name, sizeof(thread_name),
              "<lldb.host.wait4(pid=%" PRIu64 ")>", pid);
   return ThreadLauncher::LaunchThread(
-      thread_name, MonitorChildProcessThreadFunction, info_ptr, NULL);
+      thread_name, MonitorChildProcessThreadFunction, info_ptr, nullptr);
 }
 
 #ifndef __linux__
@@ -219,7 +219,7 @@ static thread_result_t MonitorChildProcessThreadFunction(void *arg) {
       bool exited = false;
       int signal = 0;
       int exit_status = 0;
-      const char *status_cstr = NULL;
+      const char *status_cstr = nullptr;
       if (WIFSTOPPED(status)) {
         signal = WSTOPSIG(status);
         status_cstr = "STOPPED";
@@ -282,7 +282,7 @@ static thread_result_t MonitorChildProcessThreadFunction(void *arg) {
   if (log)
     log->Printf("%s (arg = %p) thread exiting...", __FUNCTION__, arg);
 
-  return NULL;
+  return nullptr;
 }
 
 #endif // #if !defined (__APPLE__) && !defined (_WIN32)
@@ -393,7 +393,7 @@ const char *Host::GetSignalAsCString(int signo) {
   default:
     break;
   }
-  return NULL;
+  return nullptr;
 }
 
 #endif