| 1 | // RUN: %clangxx_msan -O2 %s -o %t && %run %t |
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| 2 | |
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| 3 | #include <sanitizer/msan_interface.h> |
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| 4 | |
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| 5 | struct S { |
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| 6 | S(int a0) : a(a0) {} |
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| 7 | int a; |
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| 8 | int b; |
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| 9 | }; |
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| 10 | |
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| 11 | // Here S is passed to FooRun as a 64-bit integer. |
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| 12 | // This triggers an optimization where 10000 * s.a is transformed into |
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| 13 | // ((*(uint64_t *)&s) * (10000 * 2**32)) >> 32 |
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| 14 | // Test that MSan understands that this kills the uninitialized high half of S |
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| 15 | // (i.e. S::b). |
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| 16 | void FooRun(S s) { |
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| 17 | int64_t x = 10000 * s.a; |
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| 18 | __msan_check_mem_is_initialized(x: &x, size: sizeof(x)); |
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| 19 | } |
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| 20 | |
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| 21 | int main(void) { |
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| 22 | S z(1); |
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| 23 | // Take &z to ensure that it is built on stack. |
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| 24 | S *volatile p = &z; |
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| 25 | FooRun(s: z); |
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| 26 | return 0; |
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| 27 | } |
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| 28 | |
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