Introduce llvm::sys::Process::getProcessId() and adopt it

Differential Revision: https://reviews.llvm.org/D78022

llvm/include/llvm/Support/Process.h

@@ -42,6 +42,11 @@ namespace sys {
 /// current executing process.
 class Process {
 public:
+  using Pid = int32_t;
+
+  /// Get the process's identifier.
+  static Pid getProcessId();
+
   /// Get the process's page size.
   /// This may fail if the underlying syscall returns an error. In most cases,
   /// page size information is used for optimization, and this error can be

llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp

@@ -34,9 +34,8 @@
 #include <mutex>
 
 #include <sys/mman.h>  // mmap()
-#include <sys/types.h> // getpid()
 #include <time.h>      // clock_gettime(), time(), localtime_r() */
-#include <unistd.h>    // for getpid(), read(), close()
+#include <unistd.h>    // for read(), close()
 
 using namespace llvm;
 using namespace llvm::object;
@@ -81,7 +80,7 @@ private:
   void NotifyDebug(uint64_t CodeAddr, DILineInfoTable Lines);
 
   // cache lookups
-  pid_t Pid;
+  sys::Process::Pid Pid;
 
   // base directory for output data
   std::string JitPath;
@@ -177,7 +176,8 @@ static inline uint64_t perf_get_timestamp(void) {
   return timespec_to_ns(&ts);
 }
 
-PerfJITEventListener::PerfJITEventListener() : Pid(::getpid()) {
+PerfJITEventListener::PerfJITEventListener()
+    : Pid(sys::Process::getProcessId()) {
   // check if clock-source is supported
   if (!perf_get_timestamp()) {
     errs() << "kernel does not support CLOCK_MONOTONIC\n";

llvm/lib/Support/CodeGenCoverage.cpp

@@ -11,20 +11,14 @@
 
 #include "llvm/Support/CodeGenCoverage.h"
 
-#include "llvm/Config/llvm-config.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Mutex.h"
+#include "llvm/Support/Process.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/ToolOutputFile.h"
 
-#if LLVM_ON_UNIX
-#include <unistd.h>
-#elif defined(_WIN32)
-#include <windows.h>
-#endif
-
 using namespace llvm;
 
 static sys::SmartMutex<true> OutputMutex;
@@ -89,14 +83,7 @@ bool CodeGenCoverage::emit(StringRef CoveragePrefix,
     // We can handle locking within a process easily enough but we don't want to
     // manage it between multiple processes. Use the process ID to ensure no
     // more than one process is ever writing to the same file at the same time.
-    std::string Pid =
-#if LLVM_ON_UNIX
-        llvm::to_string(::getpid());
-#elif defined(_WIN32)
-        llvm::to_string(::GetCurrentProcessId());
-#else
-        "";
-#endif
+    std::string Pid = llvm::to_string(sys::Process::getProcessId());
 
     std::string CoverageFilename = (CoveragePrefix + Pid).str();
 

llvm/lib/Support/LockFileManager.cpp

@@ -14,6 +14,7 @@
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Process.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cerrno>
@@ -195,12 +196,7 @@ LockFileManager::LockFileManager(StringRef FileName)
     }
 
     raw_fd_ostream Out(UniqueLockFileID, /*shouldClose=*/true);
-    Out << HostID << ' ';
-#if LLVM_ON_UNIX
-    Out << getpid();
-#else
-    Out << "1";
-#endif
+    Out << HostID << ' ' << sys::Process::getProcessId();
     Out.close();
 
     if (Out.has_error()) {

llvm/lib/Support/Unix/Process.inc

@@ -66,6 +66,12 @@ static std::pair<std::chrono::microseconds, std::chrono::microseconds> getRUsage
 #endif
 }
 
+Process::Pid Process::getProcessId() {
+  static_assert(sizeof(Pid) >= sizeof(pid_t),
+                "Process::Pid should be big enough to store pid_t");
+  return Pid(::getpid());
+}
+
 // On Cygwin, getpagesize() returns 64k(AllocationGranularity) and
 // offset in mmap(3) should be aligned to the AllocationGranularity.
 Expected<unsigned> Process::getPageSize() {

llvm/lib/Support/Windows/Process.inc

@@ -43,6 +43,12 @@
 
 using namespace llvm;
 
+Process::Pid Process::getProcessId() {
+  static_assert(sizeof(Pid) >= sizeof(DWORD),
+                "Process::Pid should be big enough to store DWORD");
+  return Pid(::GetCurrentProcessId());
+}
+
 // This function retrieves the page size using GetNativeSystemInfo() and is
 // present solely so it can be called once to initialize the self_process member
 // below.

llvm/unittests/Support/ProcessTest.cpp

@@ -21,6 +21,16 @@ namespace {
 using namespace llvm;
 using namespace sys;
 
+TEST(ProcessTest, GetProcessIdTest) {
+  const Process::Pid pid = Process::getProcessId();
+
+#ifdef _WIN32
+  EXPECT_EQ(pid, ::GetCurrentProcessId());
+#else
+  EXPECT_EQ(pid, ::getpid());
+#endif
+}
+
 TEST(ProcessTest, GetRandomNumberTest) {
   const unsigned r1 = Process::GetRandomNumber();
   const unsigned r2 = Process::GetRandomNumber();