[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

lldb/source/API/SBPlatform.cpp

@@ -28,7 +28,7 @@ using namespace lldb_private;
 
 // PlatformConnectOptions
 struct PlatformConnectOptions {
-  PlatformConnectOptions(const char *url = NULL)
+  PlatformConnectOptions(const char *url = nullptr)
       : m_url(), m_rsync_options(), m_rsync_remote_path_prefix(),
         m_rsync_enabled(false), m_rsync_omit_hostname_from_remote_path(false),
         m_local_cache_directory() {
@@ -48,7 +48,7 @@ struct PlatformConnectOptions {
 
 // PlatformShellCommand
 struct PlatformShellCommand {
-  PlatformShellCommand(const char *shell_command = NULL)
+  PlatformShellCommand(const char *shell_command = nullptr)
       : m_command(), m_working_dir(), m_status(0), m_signo(0) {
     if (shell_command && shell_command[0])
       m_command = shell_command;
@@ -94,7 +94,7 @@ const char *SBPlatformConnectOptions::GetURL() {
   LLDB_RECORD_METHOD_NO_ARGS(const char *, SBPlatformConnectOptions, GetURL);
 
   if (m_opaque_ptr->m_url.empty())
-    return NULL;
+    return nullptr;
   return m_opaque_ptr->m_url.c_str();
 }
 
@@ -188,7 +188,7 @@ const char *SBPlatformShellCommand::GetCommand() {
   LLDB_RECORD_METHOD_NO_ARGS(const char *, SBPlatformShellCommand, GetCommand);
 
   if (m_opaque_ptr->m_command.empty())
-    return NULL;
+    return nullptr;
   return m_opaque_ptr->m_command.c_str();
 }
 
@@ -207,7 +207,7 @@ const char *SBPlatformShellCommand::GetWorkingDirectory() {
                              GetWorkingDirectory);
 
   if (m_opaque_ptr->m_working_dir.empty())
-    return NULL;
+    return nullptr;
   return m_opaque_ptr->m_working_dir.c_str();
 }
 
@@ -256,7 +256,7 @@ const char *SBPlatformShellCommand::GetOutput() {
   LLDB_RECORD_METHOD_NO_ARGS(const char *, SBPlatformShellCommand, GetOutput);
 
   if (m_opaque_ptr->m_output.empty())
-    return NULL;
+    return nullptr;
   return m_opaque_ptr->m_output.c_str();
 }
 
@@ -282,7 +282,7 @@ bool SBPlatform::IsValid() const {
 SBPlatform::operator bool() const {
   LLDB_RECORD_METHOD_CONST_NO_ARGS(bool, SBPlatform, operator bool);
 
-  return m_opaque_sp.get() != NULL;
+  return m_opaque_sp.get() != nullptr;
 }
 
 void SBPlatform::Clear() {
@@ -297,7 +297,7 @@ const char *SBPlatform::GetName() {
   PlatformSP platform_sp(GetSP());
   if (platform_sp)
     return platform_sp->GetName().GetCString();
-  return NULL;
+  return nullptr;
 }
 
 lldb::PlatformSP SBPlatform::GetSP() const { return m_opaque_sp; }
@@ -312,7 +312,7 @@ const char *SBPlatform::GetWorkingDirectory() {
   PlatformSP platform_sp(GetSP());
   if (platform_sp)
     return platform_sp->GetWorkingDirectory().GetCString();
-  return NULL;
+  return nullptr;
 }
 
 bool SBPlatform::SetWorkingDirectory(const char *path) {
@@ -376,7 +376,7 @@ const char *SBPlatform::GetTriple() {
       return ConstString(arch.GetTriple().getTriple().c_str()).GetCString();
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 const char *SBPlatform::GetOSBuild() {
@@ -393,7 +393,7 @@ const char *SBPlatform::GetOSBuild() {
       }
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 const char *SBPlatform::GetOSDescription() {
@@ -410,7 +410,7 @@ const char *SBPlatform::GetOSDescription() {
       }
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 const char *SBPlatform::GetHostname() {
@@ -419,7 +419,7 @@ const char *SBPlatform::GetHostname() {
   PlatformSP platform_sp(GetSP());
   if (platform_sp)
     return platform_sp->GetHostname();
-  return NULL;
+  return nullptr;
 }
 
 uint32_t SBPlatform::GetOSMajorVersion() {
@@ -513,7 +513,7 @@ SBError SBPlatform::Run(SBPlatformShellCommand &shell_command) {
       return Status("invalid shell command (empty)");
 
     const char *working_dir = shell_command.GetWorkingDirectory();
-    if (working_dir == NULL) {
+    if (working_dir == nullptr) {
       working_dir = platform_sp->GetWorkingDirectory().GetCString();
       if (working_dir)
         shell_command.SetWorkingDirectory(working_dir);