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[libFuzzer] Make msan.test:SimpleCmpTest succeed with less trials. 

Currently SimpleCmpTest passes after 9,831,994 trials on x86_64/Linux
when the number of given trials is 10,000,000, just a little bigger than
that. This patch modifies SimpleCmpTest.cpp so that the test passes with less
trials, reducing its chances of future failures as libFuzzer evolves. More
specifically, this patch changes a 32-bit equality check to a 8-bit equality
check, making this test pass at 4,635,303 trials.

Differential Revision: https://reviews.llvm.org/D86382
This commit is contained in:
Dokyung Song 2020-08-21 22:40:26 +00:00
parent 2c9131665d
commit 9659b81b2a
1 changed files with 5 additions and 4 deletions
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9
compiler-rt/test/fuzzer/SimpleCmpTest.cpp
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@ -18,20 +18,21 @@ bool PrintOnce(int Line) {
}
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
if (Size != 24) return 0;
if (Size != 21)
return 0;
uint64_t x = 0;
int64_t y = 0;
int32_t z = 0;
uint32_t a = 0;
uint8_t a = 0;
memcpy(&x, Data, 8); // 8
memcpy(&y, Data + 8, 8); // 16
memcpy(&z, Data + 16, sizeof(z)); // 20
memcpy(&a, Data + 20, sizeof(a)); // 24
memcpy(&a, Data + 20, sizeof(a)); // 21
const bool k32bit = sizeof(void*) == 4;
if ((k32bit || x > 1234567890) && PrintOnce(__LINE__) &&
(k32bit || x < 1234567895) && PrintOnce(__LINE__) &&
a == 0x4242 && PrintOnce(__LINE__) &&
a == 0x42 && PrintOnce(__LINE__) &&
(k32bit || y >= 987654321) && PrintOnce(__LINE__) &&
(k32bit || y <= 987654325) && PrintOnce(__LINE__) &&
z < -10000 && PrintOnce(__LINE__) &&