[llvm] r175509 - 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.
Alexey Samsonov
samsonov at google.com
Tue Feb 19 12:42:25 PST 2013
On Tue, Feb 19, 2013 at 9:57 PM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
>
> On Tue, Feb 19, 2013 at 3:35 AM, Alexey Samsonov <samsonov at google.com>wrote:
>
>> Author: samsonov
>> Date: Tue Feb 19 05:35:39 2013
>> New Revision: 175509
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=175509&view=rev
>> Log:
>> 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.
>>
>
> Do we have a public bot with this configuration on it?
>
Yep, we've just created our private buildbots that bootstrap LLVM under
ASan and MSan. Re -fsanitize=init-order: we might
use it later as well, but for now it produces a lot of false positives
reports on LLVM code due to widespread "registration" machinery.
>
>
>>
>> Modified:
>> llvm/trunk/include/llvm/Support/TimeValue.h
>> llvm/trunk/lib/Support/TimeValue.cpp
>> llvm/trunk/lib/Support/Unix/TimeValue.inc
>>
>> Modified: llvm/trunk/include/llvm/Support/TimeValue.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/TimeValue.h?rev=175509&r1=175508&r2=175509&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/include/llvm/Support/TimeValue.h (original)
>> +++ llvm/trunk/include/llvm/Support/TimeValue.h Tue Feb 19 05:35:39 2013
>> @@ -240,7 +240,7 @@ namespace sys {
>> /// Posix, correcting for the difference in Posix zero time.
>> /// @brief Convert to unix time (100 nanoseconds since 12:00:00a Jan
>> 1,1970)
>> uint64_t toPosixTime() const {
>> - uint64_t result = seconds_ - PosixZeroTime.seconds_;
>> + uint64_t result = seconds_ - PosixZeroTimeSeconds;
>> result += nanos_ / NANOSECONDS_PER_POSIX_TICK;
>> return result;
>> }
>> @@ -248,14 +248,14 @@ namespace sys {
>> /// Converts the TimeValue into the corresponding number of seconds
>> /// since the epoch (00:00:00 Jan 1,1970).
>> uint64_t toEpochTime() const {
>> - return seconds_ - PosixZeroTime.seconds_;
>> + return seconds_ - PosixZeroTimeSeconds;
>> }
>>
>> /// Converts the TimeValue into the corresponding number of "ticks"
>> for
>> /// Win32 platforms, correcting for the difference in Win32 zero
>> time.
>> /// @brief Convert to windows time (seconds since 12:00:00a Jan 1,
>> 1601)
>> uint64_t toWin32Time() const {
>> - uint64_t result = seconds_ - Win32ZeroTime.seconds_;
>> + uint64_t result = seconds_ - Win32ZeroTimeSeconds;
>> result += nanos_ / NANOSECONDS_PER_WIN32_TICK;
>> return result;
>> }
>> @@ -264,7 +264,7 @@ namespace sys {
>> /// correction for the Posix zero time.
>> /// @brief Convert to timespec time (ala POSIX.1b)
>> void getTimespecTime( uint64_t& seconds, uint32_t& nanos ) const {
>> - seconds = seconds_ - PosixZeroTime.seconds_;
>> + seconds = seconds_ - PosixZeroTimeSeconds;
>> nanos = nanos_;
>> }
>>
>> @@ -331,7 +331,7 @@ namespace sys {
>> /// TimeValue and assigns that value to \p this.
>> /// @brief Convert seconds form PosixTime to TimeValue
>> void fromEpochTime( SecondsType seconds ) {
>> - seconds_ = seconds + PosixZeroTime.seconds_;
>> + seconds_ = seconds + PosixZeroTimeSeconds;
>> nanos_ = 0;
>> this->normalize();
>> }
>> @@ -340,7 +340,7 @@ namespace sys {
>> /// corresponding TimeValue and assigns that value to \p this.
>> /// @brief Convert seconds form Windows FILETIME to TimeValue
>> void fromWin32Time( uint64_t win32Time ) {
>> - this->seconds_ = win32Time / 10000000 + Win32ZeroTime.seconds_;
>> + this->seconds_ = win32Time / 10000000 + Win32ZeroTimeSeconds;
>> this->nanos_ = NanoSecondsType(win32Time % 10000000) * 100;
>> }
>>
>> @@ -360,6 +360,9 @@ namespace sys {
>> /// Store the values as a <timeval>.
>> SecondsType seconds_;///< Stores the seconds part of the TimeVal
>> NanoSecondsType nanos_; ///< Stores the nanoseconds part of the
>> TimeVal
>> +
>> + static const SecondsType PosixZeroTimeSeconds;
>> + static const SecondsType Win32ZeroTimeSeconds;
>> /// @}
>>
>> };
>>
>> Modified: llvm/trunk/lib/Support/TimeValue.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/TimeValue.cpp?rev=175509&r1=175508&r2=175509&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/Support/TimeValue.cpp (original)
>> +++ llvm/trunk/lib/Support/TimeValue.cpp Tue Feb 19 05:35:39 2013
>> @@ -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 ) {
>>
>> Modified: llvm/trunk/lib/Support/Unix/TimeValue.inc
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/TimeValue.inc?rev=175509&r1=175508&r2=175509&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/Support/Unix/TimeValue.inc (original)
>> +++ llvm/trunk/lib/Support/Unix/TimeValue.inc Tue Feb 19 05:35:39 2013
>> @@ -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 ) );
>> }
>>
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>
>
>
--
Alexey Samsonov, MSK
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