[compiler-rt] r224789 - [asan] change the coverage collection scheme so that we can easily emit coverage for the entire process as a single bit set, and if coverage_bitset=1 actually emit that bitset
Evgeniy Stepanov
eugeni.stepanov at gmail.com
Wed Dec 24 05:14:30 PST 2014
On Wed, Dec 24, 2014 at 1:32 AM, Kostya Serebryany <kcc at google.com> wrote:
> Author: kcc
> Date: Tue Dec 23 16:32:17 2014
> New Revision: 224789
>
> URL: http://llvm.org/viewvc/llvm-project?rev=224789&view=rev
> Log:
> [asan] change the coverage collection scheme so that we can easily emit coverage for the entire process as a single bit set, and if coverage_bitset=1 actually emit that bitset
>
> Modified:
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.cc
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.h
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h
> compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc
> compiler-rt/trunk/test/asan/TestCases/Linux/coverage-levels.cc
>
> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc?rev=224789&r1=224788&r2=224789&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc (original)
> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc Tue Dec 23 16:32:17 2014
> @@ -12,14 +12,16 @@
> //
> // Compiler instrumentation:
> // For every interesting basic block the compiler injects the following code:
> -// if (Guard) {
> +// if (Guard < 0) {
> // __sanitizer_cov(&Guard);
> // }
> +// At the module start up time __sanitizer_cov_module_init sets the guards
> +// to consecutive negative numbers (-1, -2, -3, ...).
> // It's fine to call __sanitizer_cov more than once for a given block.
> //
> // Run-time:
> // - __sanitizer_cov(): record that we've executed the PC (GET_CALLER_PC).
> -// and atomically set Guard to 1.
> +// and atomically set Guard to -Guard.
> // - __sanitizer_cov_dump: dump the coverage data to disk.
> // For every module of the current process that has coverage data
> // this will create a file module_name.PID.sancov. The file format is simple:
> @@ -65,14 +67,16 @@ class CoverageData {
> void BeforeFork();
> void AfterFork(int child_pid);
> void Extend(uptr npcs);
> - void Add(uptr pc, u8 *guard);
> + void Add(uptr pc, u32 *guard);
> void IndirCall(uptr caller, uptr callee, uptr callee_cache[],
> uptr cache_size);
> void DumpCallerCalleePairs();
> void DumpTrace();
>
> ALWAYS_INLINE
> - void TraceBasicaBlock(uptr *cache);
> + void TraceBasicBlock(uptr *cache);
> +
> + void InitializeGuards(s32 **guards, uptr n);
>
> uptr *data();
> uptr size();
> @@ -149,12 +153,11 @@ void CoverageData::Init() {
> pc_array = reinterpret_cast<uptr *>(
> MmapNoReserveOrDie(sizeof(uptr) * kPcArrayMaxSize, "CovInit"));
> pc_fd = kInvalidFd;
> + atomic_store(&pc_array_index, 0, memory_order_relaxed);
> if (common_flags()->coverage_direct) {
> atomic_store(&pc_array_size, 0, memory_order_relaxed);
> - atomic_store(&pc_array_index, 0, memory_order_relaxed);
> } else {
> atomic_store(&pc_array_size, kPcArrayMaxSize, memory_order_relaxed);
> - atomic_store(&pc_array_index, 0, memory_order_relaxed);
> }
>
> cc_array = reinterpret_cast<uptr **>(MmapNoReserveOrDie(
> @@ -230,15 +233,27 @@ void CoverageData::Extend(uptr npcs) {
> atomic_store(&pc_array_size, size, memory_order_release);
> }
>
> +void CoverageData::InitializeGuards(s32 **guards, uptr n) {
> + for (uptr i = 0; i < n; i++) {
> + uptr idx = atomic_fetch_add(&pc_array_index, 1, memory_order_relaxed);
> + *guards[i] = -static_cast<s32>(idx + 1);
> + }
> +}
> +
> // Atomically add the pc to the vector. The atomically set the guard to 1.
> // If the function is called more than once for a given PC it will
> // be inserted multiple times, which is fine.
This comment is no longer true, is it?
> -void CoverageData::Add(uptr pc, u8 *guard) {
> - // Set the guard.
> - atomic_uint8_t *atomic_guard = reinterpret_cast<atomic_uint8_t*>(guard);
> - atomic_store(atomic_guard, 1, memory_order_relaxed);
> +void CoverageData::Add(uptr pc, u32 *guard) {
> + atomic_uint32_t *atomic_guard = reinterpret_cast<atomic_uint32_t*>(guard);
> + s32 guard_value = atomic_load(atomic_guard, memory_order_relaxed);
> + if (guard_value >= 0) return;
> +
> + atomic_store(atomic_guard, -guard_value, memory_order_relaxed);
> if (!pc_array) return;
> - uptr idx = atomic_fetch_add(&pc_array_index, 1, memory_order_relaxed);
> +
> + uptr idx = -guard_value - 1;
> + if (idx >= atomic_load(&pc_array_index, memory_order_acquire))
> + return; // May happen after fork when pc_array_index becomes 0.
> CHECK_LT(idx * sizeof(uptr),
> atomic_load(&pc_array_size, memory_order_acquire));
> pc_array[idx] = pc;
> @@ -338,18 +353,20 @@ static void CovWritePacked(int pid, cons
> // If packed = true and name == 0: <pid>.<sancov>.<packed>.
> // If packed = true and name != 0: <name>.<sancov>.<packed> (name is
> // user-supplied).
> -static int CovOpenFile(bool packed, const char* name) {
> +static int CovOpenFile(bool packed, const char *name,
> + const char *extension = "sancov") {
> InternalScopedString path(kMaxPathLength);
> if (!packed) {
> CHECK(name);
> - path.append("%s/%s.%zd.sancov", common_flags()->coverage_dir, name,
> - internal_getpid());
> + path.append("%s/%s.%zd.%s", common_flags()->coverage_dir, name,
> + internal_getpid(), extension);
> } else {
> if (!name)
> - path.append("%s/%zd.sancov.packed", common_flags()->coverage_dir,
> - internal_getpid());
> + path.append("%s/%zd.%s.packed", common_flags()->coverage_dir,
> + internal_getpid(), extension);
> else
> - path.append("%s/%s.sancov.packed", common_flags()->coverage_dir, name);
> + path.append("%s/%s.%s.packed", common_flags()->coverage_dir, name,
> + extension);
> }
> uptr fd = OpenFile(path.data(), true);
> if (internal_iserror(fd)) {
> @@ -434,7 +451,7 @@ void CoverageData::DumpCallerCalleePairs
> // Record the current PC into the event buffer.
> // Every event is a u32 value (index in tr_pc_array_index) so we compute
> // it once and then cache in the provided 'cache' storage.
> -void CoverageData::TraceBasicaBlock(uptr *cache) {
> +void CoverageData::TraceBasicBlock(uptr *cache) {
> CHECK(common_flags()->coverage);
> uptr idx = *cache;
> if (!idx) {
> @@ -450,12 +467,33 @@ void CoverageData::TraceBasicaBlock(uptr
> tr_event_array_index++;
> }
>
> +static void CovDumpAsBitSet() {
> + if (!common_flags()->coverage_bitset) return;
> + if (!coverage_data.size()) return;
> + int fd = CovOpenFile(/* packed */false, "combined", "bitset-sancov");
> + if (fd < 0) return;
> + uptr n = coverage_data.size();
> + uptr n_set_bits = 0;
> + InternalScopedBuffer<char> out(n);
> + for (uptr i = 0; i < n; i++) {
> + uptr pc = coverage_data.data()[i];
> + out[i] = pc ? '1' : '0';
> + if (pc)
> + n_set_bits++;
> + }
> + internal_write(fd, out.data(), n);
> + internal_close(fd);
> + VReport(1, " CovDump: bitset of %zd bits written, %zd bits are set\n", n,
> + n_set_bits);
> +}
> +
> // Dump the coverage on disk.
> static void CovDump() {
> if (!common_flags()->coverage || common_flags()->coverage_direct) return;
> #if !SANITIZER_WINDOWS
> if (atomic_fetch_add(&dump_once_guard, 1, memory_order_relaxed))
> return;
> + CovDumpAsBitSet();
> uptr size = coverage_data.size();
> InternalMmapVector<u32> offsets(size);
> uptr *vb = coverage_data.data();
> @@ -539,7 +577,7 @@ void CovAfterFork(int child_pid) {
> } // namespace __sanitizer
>
> extern "C" {
> -SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov(u8 *guard) {
> +SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov(u32 *guard) {
> coverage_data.Add(StackTrace::GetPreviousInstructionPc(GET_CALLER_PC()),
> guard);
> }
> @@ -552,8 +590,11 @@ SANITIZER_INTERFACE_ATTRIBUTE void __san
> SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_init() {
> coverage_data.Init();
> }
> -SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_module_init(uptr npcs) {
> - if (!common_flags()->coverage || !common_flags()->coverage_direct) return;
> +SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_module_init(s32 **guards,
> + uptr npcs) {
> + coverage_data.InitializeGuards(guards, npcs);
> + if (!common_flags()->coverage || !common_flags()->coverage_direct)
> + return;
> if (SANITIZER_ANDROID) {
> // dlopen/dlclose interceptors do not work on Android, so we rely on
> // Extend() calls to update .sancov.map.
> @@ -572,10 +613,10 @@ uptr __sanitizer_get_total_unique_covera
>
> SANITIZER_INTERFACE_ATTRIBUTE
> void __sanitizer_cov_trace_func_enter(uptr *cache) {
> - coverage_data.TraceBasicaBlock(cache);
> + coverage_data.TraceBasicBlock(cache);
> }
> SANITIZER_INTERFACE_ATTRIBUTE
> void __sanitizer_cov_trace_basic_block(uptr *cache) {
> - coverage_data.TraceBasicaBlock(cache);
> + coverage_data.TraceBasicBlock(cache);
> }
> } // extern "C"
>
> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.cc?rev=224789&r1=224788&r2=224789&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.cc (original)
> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.cc Tue Dec 23 16:32:17 2014
> @@ -63,6 +63,7 @@ void CommonFlags::SetDefaults() {
> legacy_pthread_cond = false;
> intercept_tls_get_addr = false;
> coverage = false;
> + coverage_bitset = false;
> coverage_direct = SANITIZER_ANDROID;
> coverage_dir = ".";
> full_address_space = false;
> @@ -150,6 +151,9 @@ void CommonFlags::ParseFromString(const
> ParseFlag(str, &coverage, "coverage",
> "If set, coverage information will be dumped at program shutdown (if the "
> "coverage instrumentation was enabled at compile time).");
> + ParseFlag(str, &coverage_bitset, "coverage_bitset",
> + "If set (and if 'coverage' is set too), the coverage information "
> + "will also be dumped as a bitset to a separate file.");
> ParseFlag(str, &coverage_direct, "coverage_direct",
> "If set, coverage information will be dumped directly to a memory "
> "mapped file. This way data is not lost even if the process is "
>
> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.h
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.h?rev=224789&r1=224788&r2=224789&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.h (original)
> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.h Tue Dec 23 16:32:17 2014
> @@ -56,6 +56,7 @@ struct CommonFlags {
> uptr mmap_limit_mb;
> uptr hard_rss_limit_mb;
> bool coverage;
> + bool coverage_bitset;
> bool coverage_direct;
> const char *coverage_dir;
> bool full_address_space;
>
> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h?rev=224789&r1=224788&r2=224789&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h (original)
> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h Tue Dec 23 16:32:17 2014
> @@ -120,7 +120,7 @@ extern "C" {
>
> SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_dump();
> SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_init();
> - SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov(__sanitizer::u8 *guard);
> + SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov(__sanitizer::u32 *guard);
> SANITIZER_INTERFACE_ATTRIBUTE
> void __sanitizer_annotate_contiguous_container(const void *beg,
> const void *end,
>
> Modified: compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc?rev=224789&r1=224788&r2=224789&view=diff
> ==============================================================================
> --- compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc (original)
> +++ compiler-rt/trunk/test/asan/TestCases/Linux/coverage-fork.cc Tue Dec 23 16:32:17 2014
> @@ -33,6 +33,7 @@ int main(int argc, char **argv) {
> }
>
> // CHECK-DAG: Child PID: [[ChildPID:[0-9]+]]
> -// CHECK-DAG: [[ChildPID]].sancov: 1 PCs written
> +// Coverage in the child (after fork,before exec) is not expected to work.
> +// (disabled): [[ChildPID]].sancov: 1 PCs written
> // CHECK-DAG: Parent PID: [[ParentPID:[0-9]+]]
> // CHECK-DAG: [[ParentPID]].sancov: 3 PCs written
>
> Modified: compiler-rt/trunk/test/asan/TestCases/Linux/coverage-levels.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Linux/coverage-levels.cc?rev=224789&r1=224788&r2=224789&view=diff
> ==============================================================================
> --- compiler-rt/trunk/test/asan/TestCases/Linux/coverage-levels.cc (original)
> +++ compiler-rt/trunk/test/asan/TestCases/Linux/coverage-levels.cc Tue Dec 23 16:32:17 2014
> @@ -1,11 +1,14 @@
> // Test various levels of coverage
> //
> // RUN: %clangxx_asan -O1 -fsanitize-coverage=1 %s -o %t
> -// RUN: ASAN_OPTIONS=coverage=1:verbosity=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1
> +// RUN: ASAN_OPTIONS=coverage=1:coverage_bitset=1:verbosity=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1
> // RUN: %clangxx_asan -O1 -fsanitize-coverage=2 %s -o %t
> -// RUN: ASAN_OPTIONS=coverage=1:verbosity=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK2
> +// RUN: ASAN_OPTIONS=coverage=1:coverage_bitset=1:verbosity=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK2
> // RUN: %clangxx_asan -O1 -fsanitize-coverage=3 %s -o %t
> -// RUN: ASAN_OPTIONS=coverage=1:verbosity=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK3
> +// RUN: ASAN_OPTIONS=coverage=1:coverage_bitset=1:verbosity=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK3
> +
> +// RUN: ASAN_OPTIONS=coverage=1:coverage_bitset=0:verbosity=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK3_NOBITSET
> +// RUN: ASAN_OPTIONS=coverage=1:verbosity=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK3_NOBITSET
> //
> // REQUIRES: asan-64-bits
>
> @@ -15,6 +18,10 @@ int main(int argc, char **argv) {
> sink = 0;
> }
>
> +// CHECK1: CovDump: bitset of 1 bits written, 1 bits are set
> // CHECK1: 1 PCs written
> +// CHECK2: CovDump: bitset of 3 bits written, 2 bits are set
> // CHECK2: 2 PCs written
> +// CHECK3: CovDump: bitset of 4 bits written, 3 bits are set
> // CHECK3: 3 PCs written
> +// CHECK3_NOBITSET-NOT: bitset of
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
More information about the llvm-commits
mailing list