From 95277fbc5a050588234bc4e2a52d7902e663e3b1 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Wed, 20 Jul 2016 13:43:47 +0000 Subject: Merging r275946 and r275948: ------------------------------------------------------------------------ r275946 | bruening | 2016-07-18 22:03:38 -0700 (Mon, 18 Jul 2016) | 5 lines [esan] Fix sideline thread flaky assert Fixes an esan sideline thread CHECK that failed to account for the sideline thread reaching its code before the internal_clone() return value was assigned in the parent. ------------------------------------------------------------------------ ------------------------------------------------------------------------ r275948 | bruening | 2016-07-18 22:06:48 -0700 (Mon, 18 Jul 2016) | 4 lines [esan|wset] Fix flaky sampling tests Adds a new esan public interface routine __esan_get_sample_count() and uses it to ensure that tests of sampling receive the minimum number of samples. ------------------------------------------------------------------------ git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/branches/release_39@276114 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/sanitizer/esan_interface.h | 4 ++++ lib/esan/esan.cpp | 8 ++++++++ lib/esan/esan.h | 1 + lib/esan/esan_interface.cpp | 4 ++++ lib/esan/esan_sideline_linux.cpp | 9 ++++++++- lib/esan/working_set.cpp | 5 +++++ lib/esan/working_set.h | 1 + test/esan/TestCases/workingset-midreport.cpp | 18 +++++++++--------- test/esan/TestCases/workingset-samples.cpp | 19 ++++++++++--------- 9 files changed, 50 insertions(+), 19 deletions(-) diff --git a/include/sanitizer/esan_interface.h b/include/sanitizer/esan_interface.h index 31e9b9b4d..4aff8d47b 100644 --- a/include/sanitizer/esan_interface.h +++ b/include/sanitizer/esan_interface.h @@ -39,6 +39,10 @@ extern "C" { // data for that point in the run be reported from the tool. void COMPILER_RT_WEAK __esan_report(); +// This function returns the number of samples that the esan tool has collected +// to this point. This is useful for testing. +unsigned int COMPILER_RT_WEAK __esan_get_sample_count(); + #ifdef __cplusplus } // extern "C" #endif diff --git a/lib/esan/esan.cpp b/lib/esan/esan.cpp index 3c69b4e91..2fb77894d 100644 --- a/lib/esan/esan.cpp +++ b/lib/esan/esan.cpp @@ -259,4 +259,12 @@ void processCompilationUnitExit(void *Ptr) { } } +unsigned int getSampleCount() { + VPrintf(1, "in esan::%s\n", __FUNCTION__); + if (__esan_which_tool == ESAN_WorkingSet) { + return getSampleCountWorkingSet(); + } + return 0; +} + } // namespace __esan diff --git a/lib/esan/esan.h b/lib/esan/esan.h index 371810d5e..5a0dde627 100644 --- a/lib/esan/esan.h +++ b/lib/esan/esan.h @@ -38,6 +38,7 @@ extern bool EsanDuringInit; void initializeLibrary(ToolType Tool); int finalizeLibrary(); void reportResults(); +unsigned int getSampleCount(); // Esan creates the variable per tool per compilation unit at compile time // and passes its pointer Ptr to the runtime library. void processCompilationUnitInit(void *Ptr); diff --git a/lib/esan/esan_interface.cpp b/lib/esan/esan_interface.cpp index 8a64d1526..43b3dff86 100644 --- a/lib/esan/esan_interface.cpp +++ b/lib/esan/esan_interface.cpp @@ -115,4 +115,8 @@ extern "C" { SANITIZER_INTERFACE_ATTRIBUTE void __esan_report() { reportResults(); } + +SANITIZER_INTERFACE_ATTRIBUTE unsigned int __esan_get_sample_count() { + return getSampleCount(); +} } // extern "C" diff --git a/lib/esan/esan_sideline_linux.cpp b/lib/esan/esan_sideline_linux.cpp index ba4fe62f5..d04f5909d 100644 --- a/lib/esan/esan_sideline_linux.cpp +++ b/lib/esan/esan_sideline_linux.cpp @@ -31,6 +31,7 @@ namespace __esan { static const int SigAltStackSize = 4*1024; static const int SidelineStackSize = 4*1024; +static const uptr SidelineIdUninitialized = 1; // FIXME: we'll need some kind of TLS (can we trust that a pthread key will // work in our non-POSIX thread?) to access our data in our signal handler @@ -113,6 +114,10 @@ bool SidelineThread::launchThread(SidelineFunc takeSample, void *Arg, // We do without a guard page. Stack = static_cast(MmapOrDie(SidelineStackSize, "SidelineStack")); + // We need to handle the return value from internal_clone() not having been + // assigned yet (for our CHECK in adjustTimer()) so we ensure this has a + // sentinel value. + SidelineId = SidelineIdUninitialized; // By omitting CLONE_THREAD, the child is in its own thread group and will not // receive any of the application's signals. SidelineId = internal_clone( @@ -151,7 +156,9 @@ bool SidelineThread::joinThread() { // Must be called from the sideline thread itself. bool SidelineThread::adjustTimer(u32 FreqMilliSec) { - CHECK(internal_getpid() == SidelineId); + // The return value of internal_clone() may not have been assigned yet: + CHECK(internal_getpid() == SidelineId || + SidelineId == SidelineIdUninitialized); Freq = FreqMilliSec; struct itimerval TimerVal; TimerVal.it_interval.tv_sec = (time_t) Freq / 1000; diff --git a/lib/esan/working_set.cpp b/lib/esan/working_set.cpp index 3fde5a8b5..f39111993 100644 --- a/lib/esan/working_set.cpp +++ b/lib/esan/working_set.cpp @@ -190,6 +190,11 @@ static void takeSample(void *Arg) { } } +unsigned int getSampleCountWorkingSet() +{ + return SnapshotNum; +} + // Initialization that must be done before any instrumented code is executed. void initializeShadowWorkingSet() { CHECK(getFlags()->cache_line_size == CacheLineSize); diff --git a/lib/esan/working_set.h b/lib/esan/working_set.h index 38ff0635d..6a976c3f9 100644 --- a/lib/esan/working_set.h +++ b/lib/esan/working_set.h @@ -24,6 +24,7 @@ void initializeWorkingSet(); void initializeShadowWorkingSet(); int finalizeWorkingSet(); void reportWorkingSet(); +unsigned int getSampleCountWorkingSet(); void processRangeAccessWorkingSet(uptr PC, uptr Addr, SIZE_T Size, bool IsWrite); diff --git a/test/esan/TestCases/workingset-midreport.cpp b/test/esan/TestCases/workingset-midreport.cpp index 470e33ca3..2c29cf48c 100644 --- a/test/esan/TestCases/workingset-midreport.cpp +++ b/test/esan/TestCases/workingset-midreport.cpp @@ -17,15 +17,15 @@ const int iters = 6; int main(int argc, char **argv) { char *buf = (char *)mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - // Try to increase the probability that the sideline thread is - // scheduled. Unfortunately we can't do proper synchronization - // without some form of annotation or something. - sched_yield(); - // Do enough work to get at least 4 samples. - for (int j = 0; j < iters; ++j) { - for (int i = 0; i < size; ++i) - buf[i] = i; - sched_yield(); + // To avoid flakiness stemming from whether the sideline thread + // is scheduled enough on a loaded test machine, we coordinate + // with esan itself: + if (__esan_get_sample_count) { + while (__esan_get_sample_count() < 4) { + for (int i = 0; i < size; ++i) + buf[i] = i; + sched_yield(); + } } // Ensure a non-esan build works without ifdefs: if (__esan_report) { diff --git a/test/esan/TestCases/workingset-samples.cpp b/test/esan/TestCases/workingset-samples.cpp index 09efcd44f..cf198d2f3 100644 --- a/test/esan/TestCases/workingset-samples.cpp +++ b/test/esan/TestCases/workingset-samples.cpp @@ -1,6 +1,7 @@ // RUN: %clang_esan_wset -O0 %s -o %t 2>&1 // RUN: %run %t 2>&1 | FileCheck %s +#include #include #include #include @@ -12,15 +13,15 @@ const int iters = 6; int main(int argc, char **argv) { char *buf = (char *)mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - // Try to increase the probability that the sideline thread is - // scheduled. Unfortunately we can't do proper synchronization - // without some form of annotation or something. - sched_yield(); - // Do enough work to get at least 4 samples. - for (int j = 0; j < iters; ++j) { - for (int i = 0; i < size; ++i) - buf[i] = i; - sched_yield(); + // To avoid flakiness stemming from whether the sideline thread + // is scheduled enough on a loaded test machine, we coordinate + // with esan itself: + if (__esan_get_sample_count) { + while (__esan_get_sample_count() < 4) { + for (int i = 0; i < size; ++i) + buf[i] = i; + sched_yield(); + } } munmap(buf, size); // We only check for a few samples here to reduce the chance of flakiness. -- cgit v1.2.1