[compiler-rt] r227387 - [sanitizer] allow to reset the bb/edge coverage data inside the process while it is running (single-threaded). Also expose the current coverage set to the process.

Kostya Serebryany kcc at google.com
Wed Jan 28 16:28:27 PST 2015


On Wed, Jan 28, 2015 at 3:01 PM, Alexey Samsonov <vonosmas at gmail.com> wrote:

>
> On Wed, Jan 28, 2015 at 2:39 PM, Kostya Serebryany <kcc at google.com> wrote:
>
>> Author: kcc
>> Date: Wed Jan 28 16:39:44 2015
>> New Revision: 227387
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=227387&view=rev
>> Log:
>> [sanitizer] allow to reset the bb/edge coverage data inside the process
>> while it is running (single-threaded). Also expose the current coverage set
>> to the process.
>>
>> Added:
>>     compiler-rt/trunk/test/asan/TestCases/Linux/coverage-reset.cc
>> Modified:
>>     compiler-rt/trunk/include/sanitizer/common_interface_defs.h
>>     compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
>>
>> Modified: compiler-rt/trunk/include/sanitizer/common_interface_defs.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/include/sanitizer/common_interface_defs.h?rev=227387&r1=227386&r2=227387&view=diff
>>
>> ==============================================================================
>> --- compiler-rt/trunk/include/sanitizer/common_interface_defs.h (original)
>> +++ compiler-rt/trunk/include/sanitizer/common_interface_defs.h Wed Jan
>> 28 16:39:44 2015
>> @@ -74,6 +74,14 @@ extern "C" {
>>    // This can be useful for coverage-directed in-process fuzzers.
>>    uintptr_t __sanitizer_get_total_unique_coverage();
>>
>> +  // Reset the basic-block (edge) coverage to the initial state.
>> +  // Useful for in-process fuzzing to start collecting coverage from
>> scratch.
>> +  // Experimental, will likely not work for multi-threaded process.
>> +  void __sanitizer_reset_coverage();
>> +  // Set *data to the array of covered PCs and return the size of that
>> array.
>> +  // Some of the entries in *data will be zero.
>> +  uintptr_t __sanitizer_get_coverage_guards(uintptr_t **data);
>>
>
> ^^^
> I feel that the number of coverage-related functions is substantial enough
> to move them to a dedicated <sanitizer/coverage_interface.h> header.
>

Oh my... Yea, maybe..


>
>
>> +
>>    // Annotate the current state of a contiguous container, such as
>>    // std::vector, std::string or similar.
>>    // A contiguous container is a container that keeps all of its elements
>>
>> 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=227387&r1=227386&r2=227387&view=diff
>>
>> ==============================================================================
>> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
>> (original)
>> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
>> Wed Jan 28 16:39:44 2015
>> @@ -83,6 +83,7 @@ class CoverageData {
>>
>>    void InitializeGuardArray(s32 *guards);
>>    void InitializeGuards(s32 *guards, uptr n);
>> +  void ReinitializeGuards();
>>
>>    uptr *data();
>>    uptr size();
>> @@ -211,6 +212,13 @@ void CoverageData::Disable() {
>>    }
>>  }
>>
>> +void CoverageData::ReinitializeGuards() {
>> +  // Assuming single thread.
>> +  atomic_store(&pc_array_index, 0, memory_order_relaxed);
>> +  for (uptr i = 0; i < guard_array_vec.size(); i++)
>> +    InitializeGuardArray(guard_array_vec[i]);
>> +}
>> +
>>  void CoverageData::ReInit() {
>>    Disable();
>>    if (coverage_enabled) {
>> @@ -228,8 +236,7 @@ void CoverageData::ReInit() {
>>    // Re-initialize the guards.
>>    // We are single-threaded now, no need to grab any lock.
>>    CHECK_EQ(atomic_load(&pc_array_index, memory_order_relaxed), 0);
>> -  for (uptr i = 0; i < guard_array_vec.size(); i++)
>> -    InitializeGuardArray(guard_array_vec[i]);
>> +  ReinitializeGuards();
>>  }
>>
>>  void CoverageData::BeforeFork() {
>> @@ -689,4 +696,16 @@ SANITIZER_INTERFACE_ATTRIBUTE
>>  void __sanitizer_cov_trace_basic_block(s32 *id) {
>>    coverage_data.TraceBasicBlock(id);
>>  }
>> +SANITIZER_INTERFACE_ATTRIBUTE
>> +void __sanitizer_reset_coverage() {
>> +  coverage_data.ReinitializeGuards();
>> +  internal_bzero_aligned16(
>> +      coverage_data.data(),
>> +      RoundUpTo(coverage_data.size() * sizeof(coverage_data.data()[0]),
>> 16));
>> +}
>> +SANITIZER_INTERFACE_ATTRIBUTE
>> +uptr __sanitizer_get_coverage_guards(uptr **data) {
>> +  *data = coverage_data.data();
>> +  return coverage_data.size();
>> +}
>>  }  // extern "C"
>>
>> Added: compiler-rt/trunk/test/asan/TestCases/Linux/coverage-reset.cc
>> URL:
>> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Linux/coverage-reset.cc?rev=227387&view=auto
>>
>> ==============================================================================
>> --- compiler-rt/trunk/test/asan/TestCases/Linux/coverage-reset.cc (added)
>> +++ compiler-rt/trunk/test/asan/TestCases/Linux/coverage-reset.cc Wed Jan
>> 28 16:39:44 2015
>> @@ -0,0 +1,52 @@
>> +// Test __sanitizer_reset_coverage().
>> +
>> +// RUN: %clangxx_asan -fsanitize-coverage=1 %s -o %t
>> +// RUN: ASAN_OPTIONS=coverage=1 %run %t
>> +
>> +#include <sanitizer/common_interface_defs.h>
>> +#include <stdio.h>
>> +#include <assert.h>
>> +static volatile int sink;
>> +__attribute__((noinline)) void bar() { sink = 2; }
>> +__attribute__((noinline)) void foo() { sink = 1; }
>> +
>> +#define GET_AND_PRINT_COVERAGE()                                       \
>> +  bitset = 0;                                                  \
>> +  for (size_t i = 0; i < n_guards; i++)                        \
>> +    if (guards[i]) bitset |= 1U << i;                          \
>> +  printf("line %d: bitset %zd total: %zd\n", __LINE__, bitset, \
>> +         __sanitizer_get_total_unique_coverage());
>> +
>> +#define IS_POWER_OF_TWO(a) ((a & ((a) - 1)) == 0)
>> +
>> +int main() {
>> +  size_t *guards = 0;
>> +  size_t bitset;
>> +  size_t n_guards = __sanitizer_get_coverage_guards(&guards);
>> +
>> +  GET_AND_PRINT_COVERAGE();
>> +  size_t main_bit = bitset;
>> +  assert(IS_POWER_OF_TWO(main_bit));
>> +
>> +  foo();
>> +  GET_AND_PRINT_COVERAGE();
>> +  size_t foo_bit = bitset & ~main_bit;
>> +  assert(IS_POWER_OF_TWO(foo_bit));
>> +
>> +  bar();
>> +  GET_AND_PRINT_COVERAGE();
>> +  size_t bar_bit = bitset & ~(main_bit | foo_bit);
>> +  assert(IS_POWER_OF_TWO(bar_bit));
>> +
>> +  __sanitizer_reset_coverage();
>> +  GET_AND_PRINT_COVERAGE();
>> +  assert(bitset == 0);
>> +
>> +  foo();
>> +  GET_AND_PRINT_COVERAGE();
>> +  assert(bitset == foo_bit);
>> +
>> +  bar();
>> +  GET_AND_PRINT_COVERAGE();
>> +  assert(bitset == (foo_bit | bar_bit));
>> +}
>>
>>
>> _______________________________________________
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>>
>
>
>
> --
> Alexey Samsonov
> vonosmas at gmail.com
>
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