[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

2 files changed, 6 insertions, 5 deletions

diff --git a/lldb/source/Host/linux/Host.cpp b/lldb/source/Host/linux/Host.cpp
index 03fa798f0f5..f6a8766a71c 100644
--- a/lldb/source/Host/linux/Host.cpp
+++ b/lldb/source/Host/linux/Host.cpp
@@ -216,12 +216,12 @@ uint32_t Host::FindProcesses(const ProcessInstanceInfoMatch &match_info,
 
   DIR *dirproc = opendir(procdir);
   if (dirproc) {
-    struct dirent *direntry = NULL;
+    struct dirent *direntry = nullptr;
     const uid_t our_uid = getuid();
     const lldb::pid_t our_pid = getpid();
     bool all_users = match_info.GetMatchAllUsers();
 
-    while ((direntry = readdir(dirproc)) != NULL) {
+    while ((direntry = readdir(dirproc)) != nullptr) {
       if (direntry->d_type != DT_DIR || !IsDirNumeric(direntry->d_name))
         continue;
 
@@ -269,8 +269,8 @@ bool Host::FindProcessThreads(const lldb::pid_t pid, TidMap &tids_to_attach) {
   DIR *dirproc = opendir(process_task_dir.c_str());
 
   if (dirproc) {
-    struct dirent *direntry = NULL;
-    while ((direntry = readdir(dirproc)) != NULL) {
+    struct dirent *direntry = nullptr;
+    while ((direntry = readdir(dirproc)) != nullptr) {
       if (direntry->d_type != DT_DIR || !IsDirNumeric(direntry->d_name))
         continue;
 
diff --git a/lldb/source/Host/linux/HostInfoLinux.cpp b/lldb/source/Host/linux/HostInfoLinux.cpp
index 2b2207e7afa..78dd77b61fa 100644
--- a/lldb/source/Host/linux/HostInfoLinux.cpp
+++ b/lldb/source/Host/linux/HostInfoLinux.cpp
@@ -121,7 +121,8 @@ llvm::StringRef HostInfoLinux::GetDistributionId() {
 
       // retrieve the distribution id string.
       char distribution_id[256] = {'\0'};
-      if (fgets(distribution_id, sizeof(distribution_id) - 1, file) != NULL) {
+      if (fgets(distribution_id, sizeof(distribution_id) - 1, file) !=
+          nullptr) {
         if (log)
           log->Printf("distribution id command returned \"%s\"",
                       distribution_id);