Use int64_t for thread ids instead of int32_t

Apple's XNU kernel uses 64-bit thread ids. It is imprudent to assume that the top 32 bits are clear.

PiperOrigin-RevId: 706972768

Author: majnemer

tsl/platform/env.cc

@@ -17,10 +17,12 @@ limitations under the License.
 
 #include <sys/stat.h>
 
+#include <cstdint>
 #include <deque>
 #include <utility>
 #include <vector>
 
+#include "absl/strings/str_format.h"
 #include "tsl/platform/env_time.h"
 #include "tsl/platform/errors.h"
 #include "tsl/platform/host_info.h"
@@ -445,12 +447,12 @@ bool Env::LocalTempFilename(string* filename) {
 }
 
 bool Env::CreateUniqueFileName(string* prefix, const string& suffix) {
-  int32_t tid = GetCurrentThreadId();
+  int64_t tid = GetCurrentThreadId();
   int32_t pid = GetProcessId();
   long long now_microsec = NowMicros();  // NOLINT
 
-  *prefix += strings::Printf("%s-%x-%d-%llx", port::Hostname().c_str(), tid,
-                             pid, now_microsec);
+  absl::StrAppendFormat(prefix, "%s-%x-%d-%llx", port::Hostname(), tid, pid,
+                        now_microsec);
 
   if (!suffix.empty()) {
     *prefix += suffix;

tsl/platform/env.h

@@ -461,7 +461,7 @@ class Env {
   // Posix: Returns pthread id which is only guaranteed to be unique within a
   //        process.
   // Windows: Returns thread id which is unique.
-  virtual int32 GetCurrentThreadId() = 0;
+  virtual int64_t GetCurrentThreadId() = 0;
 
   // Copies current thread name to "name". Returns true if success.
   virtual bool GetCurrentThreadName(std::string* name) = 0;
@@ -559,7 +559,9 @@ class EnvWrapper : public Env {
                       absl::AnyInvocable<void()> fn) override {
     return target_->StartThread(thread_options, name, std::move(fn));
   }
-  int32 GetCurrentThreadId() override { return target_->GetCurrentThreadId(); }
+  int64_t GetCurrentThreadId() override {
+    return target_->GetCurrentThreadId();
+  }
   bool GetCurrentThreadName(std::string* name) override {
     return target_->GetCurrentThreadName(name);
   }