[sancov] enabling coverage edge pruning by default.

[eugenis]

LGTM
Maybe extend one of the tests to cover the non-pruning mode?

[aizatsky]

Maybe extend one of the tests to cover the non-pruning mode?

I will delete the flag really soon if everything is smooth. Don't see a point to add a test that I will delete in next cl.

compiler-rt/trunk/test/asan/TestCases/Posix/coverage-sandboxing.cc

else if (argc == 3)
     // Write to packed file, split into blocks (as if writing to a socket).
     args.coverage_max_block_size = 100;
   __sanitizer_sandbox_on_notify(&args);
   return 0;
 }
 #endif
 
 // CHECK-vanilla: PID: [[PID:[0-9]+]]
-// CHECK-vanilla: .so.[[PID]].sancov: 258 PCs written
+// CHECK-vanilla: .so.[[PID]].sancov: 257 PCs written
 // CHECK-vanilla: [[PID]].sancov: 1 PCs written
 
 // CHECK-sandbox: PID: [[PID:[0-9]+]]
-// CHECK-sandbox: 258 PCs written to packed file
+// CHECK-sandbox: 257 PCs written to packed file

compiler-rt/trunk/test/asan/TestCases/coverage-levels.cc

 volatile int sink;
 int main(int argc, char **argv) {
   if (argc == 0)
     sink = 0;
 }
 
 // CHECK1: CovDump: bitset of 1 bits written for '{{.*}}', 1 bits are set
 // CHECK1:  1 PCs written
-// CHECK2: CovDump: bitset of 3 bits written for '{{.*}}', 2 bits are set
-// CHECK2:  2 PCs written
-// CHECK3: CovDump: bitset of 4 bits written for '{{.*}}', 3 bits are set
-// CHECK3:  3 PCs written
+// CHECK2: CovDump: bitset of 2 bits written for '{{.*}}', 1 bits are set
+// CHECK2:  1 PCs written
+// CHECK3: CovDump: bitset of 3 bits written for '{{.*}}', 2 bits are set
+// CHECK3:  2 PCs written
 // CHECK3_NOBITSET-NOT: bitset of
 // CHECK3_NOPCS-NOT: PCs written
-// CHECK_COUNTERS: CovDump: 4 counters written for
+// CHECK_COUNTERS: CovDump: 3 counters written for

compiler-rt/trunk/test/asan/TestCases/coverage-pc-buffer.cc

int main() {
   assert(buf1 == buf);
   assert(sz1 > sz);
 
   bar();
   uintptr_t *buf2 = NULL;
   uintptr_t sz2 = __sanitizer_get_coverage_pc_buffer(&buf2);
   assertNotZeroPcs(buf2, sz2);
   assert(buf2 == buf);
-  assert(sz2 > sz1);
+  assert(sz2 == sz1);
 
   __sanitizer_reset_coverage();
   uintptr_t *buf3 = NULL;
   uintptr_t sz3 = __sanitizer_get_coverage_pc_buffer(&buf3);
   assertNotZeroPcs(buf3, sz3);
   assert(buf3 == buf);
   assert(sz3 < sz2);
 }

compiler-rt/trunk/test/msan/coverage-levels.cc

#endif
   if (argc == 0)
     sink = 0;
   return *(volatile int*)&var;
 }
 
 // CHECK_WARN: WARNING: MemorySanitizer: use-of-uninitialized-value
 // CHECK_NOWARN-NOT: ERROR
 // CHECK1:  1 PCs written
-// CHECK2:  2 PCs written
-// CHECK3:  3 PCs written
+// CHECK2:  1 PCs written
+// CHECK3:  2 PCs written

compiler-rt/trunk/test/ubsan/TestCases/Misc/coverage-levels.cc

 
 // CHECK_WARN: shift exponent 32 is too large
 // CHECK_NOWARN-NOT: ERROR
 // FIXME: Currently, coverage instrumentation kicks in after ubsan, so we get
 // more than the minimal number of instrumented blocks.
 // FIXME: Currently, ubsan with -fno-sanitize-recover and w/o asan will fail
 // to dump coverage.
 // CHECK1:  1 PCs written
-// CHECK2:  3 PCs written
-// CHECK3:  3 PCs written
+// CHECK2:  2 PCs written
+// CHECK3:  2 PCs written