1 files changed, 106 insertions, 76 deletions

diff --git a/abseil-cpp/absl/base/internal/sysinfo.cc b/abseil-cpp/absl/base/internal/sysinfo.cc
index 349d926..8bcc4fa 100644
--- a/abseil-cpp/absl/base/internal/sysinfo.cc
+++ b/abseil-cpp/absl/base/internal/sysinfo.cc
@@ -41,6 +41,7 @@
 #include <string.h>
 
 #include <cassert>
+#include <cerrno>
 #include <cstdint>
 #include <cstdio>
 #include <cstdlib>
@@ -61,14 +62,82 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace base_internal {
 
+namespace {
+
+#if defined(_WIN32)
+
+// Returns number of bits set in `bitMask`
+DWORD Win32CountSetBits(ULONG_PTR bitMask) {
+  for (DWORD bitSetCount = 0; ; ++bitSetCount) {
+    if (bitMask == 0) return bitSetCount;
+    bitMask &= bitMask - 1;
+  }
+}
+
+// Returns the number of logical CPUs using GetLogicalProcessorInformation(), or
+// 0 if the number of processors is not available or can not be computed.
+// https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getlogicalprocessorinformation
+int Win32NumCPUs() {
+#pragma comment(lib, "kernel32.lib")
+  using Info = SYSTEM_LOGICAL_PROCESSOR_INFORMATION;
+
+  DWORD info_size = sizeof(Info);
+  Info* info(static_cast<Info*>(malloc(info_size)));
+  if (info == nullptr) return 0;
+
+  bool success = GetLogicalProcessorInformation(info, &info_size);
+  if (!success && GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
+    free(info);
+    info = static_cast<Info*>(malloc(info_size));
+    if (info == nullptr) return 0;
+    success = GetLogicalProcessorInformation(info, &info_size);
+  }
+
+  DWORD logicalProcessorCount = 0;
+  if (success) {
+    Info* ptr = info;
+    DWORD byteOffset = 0;
+    while (byteOffset + sizeof(Info) <= info_size) {
+      switch (ptr->Relationship) {
+        case RelationProcessorCore:
+          logicalProcessorCount += Win32CountSetBits(ptr->ProcessorMask);
+          break;
+
+        case RelationNumaNode:
+        case RelationCache:
+        case RelationProcessorPackage:
+          // Ignore other entries
+          break;
+
+        default:
+          // Ignore unknown entries
+          break;
+      }
+      byteOffset += sizeof(Info);
+      ptr++;
+    }
+  }
+  free(info);
+  return static_cast<int>(logicalProcessorCount);
+}
+
+#endif
+
+}  // namespace
+
 static int GetNumCPUs() {
 #if defined(__myriad2__)
   return 1;
+#elif defined(_WIN32)
+  const int hardware_concurrency = Win32NumCPUs();
+  return hardware_concurrency ? hardware_concurrency : 1;
+#elif defined(_AIX)
+  return sysconf(_SC_NPROCESSORS_ONLN);
 #else
   // Other possibilities:
   //  - Read /sys/devices/system/cpu/online and use cpumask_parse()
   //  - sysconf(_SC_NPROCESSORS_ONLN)
-  return std::thread::hardware_concurrency();
+  return static_cast<int>(std::thread::hardware_concurrency());
 #endif
 }
 
@@ -91,7 +160,7 @@ static double GetNominalCPUFrequency() {
     DWORD type = 0;
     DWORD data = 0;
     DWORD data_size = sizeof(data);
-    auto result = RegQueryValueExA(key, "~MHz", 0, &type,
+    auto result = RegQueryValueExA(key, "~MHz", nullptr, &type,
                                    reinterpret_cast<LPBYTE>(&data), &data_size);
     RegCloseKey(key);
     if (result == ERROR_SUCCESS && type == REG_DWORD &&
@@ -121,12 +190,21 @@ static double GetNominalCPUFrequency() {
 // and the memory location pointed to by value is set to the value read.
 static bool ReadLongFromFile(const char *file, long *value) {
   bool ret = false;
-  int fd = open(file, O_RDONLY);
+#if defined(_POSIX_C_SOURCE)
+  const int file_mode = (O_RDONLY | O_CLOEXEC);
+#else
+  const int file_mode = O_RDONLY;
+#endif
+
+  int fd = open(file, file_mode);
   if (fd != -1) {
     char line[1024];
     char *err;
     memset(line, '\0', sizeof(line));
-    int len = read(fd, line, sizeof(line) - 1);
+    ssize_t len;
+    do {
+      len = read(fd, line, sizeof(line) - 1);
+    } while (len < 0 && errno == EINTR);
     if (len <= 0) {
       ret = false;
     } else {
@@ -154,8 +232,8 @@ static int64_t ReadMonotonicClockNanos() {
   int rc = clock_gettime(CLOCK_MONOTONIC, &t);
 #endif
   if (rc != 0) {
-    perror("clock_gettime() failed");
-    abort();
+    ABSL_INTERNAL_LOG(
+        FATAL, "clock_gettime() failed: (" + std::to_string(errno) + ")");
   }
   return int64_t{t.tv_sec} * 1000000000 + t.tv_nsec;
 }
@@ -308,7 +386,7 @@ pid_t GetTID() {
 #endif
 
 pid_t GetTID() {
-  return syscall(SYS_gettid);
+  return static_cast<pid_t>(syscall(SYS_gettid));
 }
 
 #elif defined(__akaros__)
@@ -343,81 +421,33 @@ pid_t GetTID() {
   return tid;
 }
 
-#else
+#elif defined(__APPLE__)
 
-// Fallback implementation of GetTID using pthread_getspecific.
-ABSL_CONST_INIT static once_flag tid_once;
-ABSL_CONST_INIT static pthread_key_t tid_key;
-ABSL_CONST_INIT static absl::base_internal::SpinLock tid_lock(
-    absl::kConstInit, base_internal::SCHEDULE_KERNEL_ONLY);
-
-// We set a bit per thread in this array to indicate that an ID is in
-// use. ID 0 is unused because it is the default value returned by
-// pthread_getspecific().
-ABSL_CONST_INIT static std::vector<uint32_t> *tid_array
-    ABSL_GUARDED_BY(tid_lock) = nullptr;
-static constexpr int kBitsPerWord = 32;  // tid_array is uint32_t.
-
-// Returns the TID to tid_array.
-static void FreeTID(void *v) {
-  intptr_t tid = reinterpret_cast<intptr_t>(v);
-  int word = tid / kBitsPerWord;
-  uint32_t mask = ~(1u << (tid % kBitsPerWord));
-  absl::base_internal::SpinLockHolder lock(&tid_lock);
-  assert(0 <= word && static_cast<size_t>(word) < tid_array->size());
-  (*tid_array)[word] &= mask;
+pid_t GetTID() {
+  uint64_t tid;
+  // `nullptr` here implies this thread.  This only fails if the specified
+  // thread is invalid or the pointer-to-tid is null, so we needn't worry about
+  // it.
+  pthread_threadid_np(nullptr, &tid);
+  return static_cast<pid_t>(tid);
 }
 
-static void InitGetTID() {
-  if (pthread_key_create(&tid_key, FreeTID) != 0) {
-    // The logging system calls GetTID() so it can't be used here.
-    perror("pthread_key_create failed");
-    abort();
-  }
+#elif defined(__native_client__)
 
-  // Initialize tid_array.
-  absl::base_internal::SpinLockHolder lock(&tid_lock);
-  tid_array = new std::vector<uint32_t>(1);
-  (*tid_array)[0] = 1;  // ID 0 is never-allocated.
-}
-
-// Return a per-thread small integer ID from pthread's thread-specific data.
 pid_t GetTID() {
-  absl::call_once(tid_once, InitGetTID);
-
-  intptr_t tid = reinterpret_cast<intptr_t>(pthread_getspecific(tid_key));
-  if (tid != 0) {
-    return tid;
-  }
-
-  int bit;  // tid_array[word] = 1u << bit;
-  size_t word;
-  {
-    // Search for the first unused ID.
-    absl::base_internal::SpinLockHolder lock(&tid_lock);
-    // First search for a word in the array that is not all ones.
-    word = 0;
-    while (word < tid_array->size() && ~(*tid_array)[word] == 0) {
-      ++word;
-    }
-    if (word == tid_array->size()) {
-      tid_array->push_back(0);  // No space left, add kBitsPerWord more IDs.
-    }
-    // Search for a zero bit in the word.
-    bit = 0;
-    while (bit < kBitsPerWord && (((*tid_array)[word] >> bit) & 1) != 0) {
-      ++bit;
-    }
-    tid = (word * kBitsPerWord) + bit;
-    (*tid_array)[word] |= 1u << bit;  // Mark the TID as allocated.
-  }
+  auto* thread = pthread_self();
+  static_assert(sizeof(pid_t) == sizeof(thread),
+                "In NaCL int expected to be the same size as a pointer");
+  return reinterpret_cast<pid_t>(thread);
+}
 
-  if (pthread_setspecific(tid_key, reinterpret_cast<void *>(tid)) != 0) {
-    perror("pthread_setspecific failed");
-    abort();
-  }
+#else
 
-  return static_cast<pid_t>(tid);
+// Fallback implementation of `GetTID` using `pthread_self`.
+pid_t GetTID() {
+  // `pthread_t` need not be arithmetic per POSIX; platforms where it isn't
+  // should be handled above.
+  return static_cast<pid_t>(pthread_self());
 }
 
 #endif
@@ -426,7 +456,7 @@ pid_t GetTID() {
 // userspace construct) to avoid unnecessary system calls. Without this caching,
 // it can take roughly 98ns, while it takes roughly 1ns with this caching.
 pid_t GetCachedTID() {
-#if ABSL_HAVE_THREAD_LOCAL
+#ifdef ABSL_HAVE_THREAD_LOCAL
   static thread_local pid_t thread_id = GetTID();
   return thread_id;
 #else