Fix initialization-order bug in llvm::Support::TimeValue. TimeValue::now() is explicitly called during module initialization of lib/Support/Process.cpp. It reads the field of global object PosixZeroTime, which is not guaranteed to be initialized at this point. Found by AddressSanitizer with -fsanitize=init-order option.

llvm-svn: 175509

2 files changed, 9 insertions, 3 deletions

diff --git a/llvm/lib/Support/TimeValue.cpp b/llvm/lib/Support/TimeValue.cpp
index 1a0f7bc3639..bd8af174bcd 100644
--- a/llvm/lib/Support/TimeValue.cpp
+++ b/llvm/lib/Support/TimeValue.cpp
@@ -17,11 +17,16 @@
 namespace llvm {
 using namespace sys;
 
+const TimeValue::SecondsType
+  TimeValue::PosixZeroTimeSeconds = -946684800;
+const TimeValue::SecondsType
+  TimeValue::Win32ZeroTimeSeconds = -12591158400ULL;
+
 const TimeValue TimeValue::MinTime       = TimeValue ( INT64_MIN,0 );
 const TimeValue TimeValue::MaxTime       = TimeValue ( INT64_MAX,0 );
 const TimeValue TimeValue::ZeroTime      = TimeValue ( 0,0 );
-const TimeValue TimeValue::PosixZeroTime = TimeValue ( -946684800,0 );
-const TimeValue TimeValue::Win32ZeroTime = TimeValue ( -12591158400ULL,0 );
+const TimeValue TimeValue::PosixZeroTime = TimeValue ( PosixZeroTimeSeconds,0 );
+const TimeValue TimeValue::Win32ZeroTime = TimeValue ( Win32ZeroTimeSeconds,0 );
 
 void
 TimeValue::normalize( void ) {
diff --git a/llvm/lib/Support/Unix/TimeValue.inc b/llvm/lib/Support/Unix/TimeValue.inc
index 5cf5a9d44ed..df8558bf8be 100644
--- a/llvm/lib/Support/Unix/TimeValue.inc
+++ b/llvm/lib/Support/Unix/TimeValue.inc
@@ -48,7 +48,8 @@ TimeValue TimeValue::now() {
   }
 
   return TimeValue(
-    static_cast<TimeValue::SecondsType>( the_time.tv_sec + PosixZeroTime.seconds_ ),
+    static_cast<TimeValue::SecondsType>( the_time.tv_sec +
+      PosixZeroTimeSeconds ),
     static_cast<TimeValue::NanoSecondsType>( the_time.tv_usec *
       NANOSECONDS_PER_MICROSECOND ) );
 }