[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
Kostya Serebryany
kcc at google.com
Tue Dec 23 14:32:18 PST 2014
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.
-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
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