[compiler-rt] r294166 - [XRay][compiler-rt] Use gettid instead of getpid in FDR mode.

[Dean Michael Berris via llvm-commits]

Author: dberris
Date: Sun Feb  5 19:48:21 2017
New Revision: 294166

URL: http://llvm.org/viewvc/llvm-project?rev=294166&view=rev
Log:
[XRay][compiler-rt] Use gettid instead of getpid in FDR mode.

Summary:
This was pointed out that FDR mode didn't quite put the thread ID in the
buffers, but instead would write down the parent process ID.

Reviewers: pelikan, rSerge

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D29484

Modified:
    compiler-rt/trunk/lib/xray/xray_fdr_logging.cc

Modified: compiler-rt/trunk/lib/xray/xray_fdr_logging.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_fdr_logging.cc?rev=294166&r1=294165&r2=294166&view=diff
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_fdr_logging.cc (original)
+++ compiler-rt/trunk/lib/xray/xray_fdr_logging.cc Sun Feb  5 19:48:21 2017
@@ -20,6 +20,7 @@
 #include <cassert>
 #include <cstring>
 #include <memory>
+#include <sys/syscall.h>
 #include <sys/time.h>
 #include <time.h>
 #include <unistd.h>
@@ -200,8 +201,8 @@ void setupNewBuffer(const BufferQueue::B
     auto &NewBuffer = *reinterpret_cast<MetadataRecord *>(&Records[0]);
     NewBuffer.Type = RecordType::Metadata;
     NewBuffer.RecordKind = MetadataRecord::RecordKinds::NewBuffer;
-    pid_t Pid = getpid();
-    std::memcpy(&NewBuffer.Data, &Pid, sizeof(pid_t));
+    pid_t Tid = syscall(SYS_gettid);
+    std::memcpy(&NewBuffer.Data, &Tid, sizeof(pid_t));
   }
 
   // Also write the WalltimeMarker record.