[lldb/Host] Add missing proc states

[rupprecht]

Summary

The /proc/<pid>/status parsing is missing a few cases:

• Idle
• Parked
• Dead

If we encounter an unknown proc state, this leads to an msan warning. In reality, we only check that the state != Zombie, so it doesn't really matter that we handle all cases, but handle them anyway (current list: [1]). Also explicitly set it to unknown if we encounter an unknown state. There will still be an msan warning if the proc entry has no State: line, but that should not happen.

Use a StringSwitch to make the handling of proc states a little more compact.

[1] https://github.com/torvalds/linux/blob/master/fs/proc/array.c

lldb/source/Host/linux/Host.cpp

 #include <fcntl.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/utsname.h>
 #include <unistd.h>
 
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/Object/ELF.h"
 #include "llvm/Support/ScopedPrinter.h"
 
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/ProcessInfo.h"
 #include "lldb/Utility/Status.h"
 
 #include "lldb/Host/FileSystem.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
 #include "lldb/Host/linux/Support.h"
 #include "lldb/Utility/DataExtractor.h"
 
 using namespace lldb;
 using namespace lldb_private;
 
 namespace {
 enum class ProcessState {
   Unknown,
+  Dead,
   DiskSleep,
+  Idle,
   Paging,
+  Parked,
   Running,
   Sleeping,
   TracedOrStopped,
   Zombie,
 };
 }
 
 namespace lldb_private {
 class ProcessLaunchInfo;
 }
 
 static bool GetStatusInfo(::pid_t Pid, ProcessInstanceInfo &ProcessInfo,
                           ProcessState &State, ::pid_t &TracerPid) {
+  Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+
   auto BufferOrError = getProcFile(Pid, "status");
   if (!BufferOrError)
     return false;
 
   llvm::StringRef Rest = BufferOrError.get()->getBuffer();
-  while(!Rest.empty()) {
+  while (!Rest.empty()) {
     llvm::StringRef Line;
     std::tie(Line, Rest) = Rest.split('\n');
 
     if (Line.consume_front("Gid:")) {
       // Real, effective, saved set, and file system GIDs. Read the first two.
       Line = Line.ltrim();
       uint32_t RGid, EGid;
       Line.consumeInteger(10, RGid);
if (Line.consume_front("Gid:")) {
 
       ProcessInfo.SetUserID(RUid);
       ProcessInfo.SetEffectiveUserID(EUid);
     } else if (Line.consume_front("PPid:")) {
       ::pid_t PPid;
       Line.ltrim().consumeInteger(10, PPid);
       ProcessInfo.SetParentProcessID(PPid);
     } else if (Line.consume_front("State:")) {
-      char S = Line.ltrim().front();
-      switch (S) {
-      case 'R':
-        State = ProcessState::Running;
-        break;
-      case 'S':
-        State = ProcessState::Sleeping;
-        break;
-      case 'D':
-        State = ProcessState::DiskSleep;
-        break;
-      case 'Z':
-        State = ProcessState::Zombie;
-        break;
-      case 'T':
-        State = ProcessState::TracedOrStopped;
-        break;
-      case 'W':
-        State = ProcessState::Paging;
-        break;
+      State = llvm::StringSwitch<ProcessState>(Line.ltrim().take_front(1))
+                  .Case("D", ProcessState::DiskSleep)
+                  .Case("I", ProcessState::Idle)
+                  .Case("R", ProcessState::Running)
+                  .Case("S", ProcessState::Sleeping)
+                  .CaseLower("T", ProcessState::TracedOrStopped)
+                  .Case("W", ProcessState::Paging)
+                  .Case("P", ProcessState::Parked)
+                  .Case("X", ProcessState::Dead)
+                  .Case("Z", ProcessState::Zombie)
+                  .Default(ProcessState::Unknown);
+      if (State == ProcessState::Unknown) {
+        LLDB_LOG(log, "Unknown process state {0}", Line);
       }
     } else if (Line.consume_front("TracerPid:")) {
       Line = Line.ltrim();
       Line.consumeInteger(10, TracerPid);
     }
   }
   return true;
 }