fc1d39849e
DFSan has flags to control flows between pointers and objects referred by pointers. For example, a = *p; L(a) = L(*p) when -dfsan-combine-pointer-labels-on-load = false L(a) = L(*p) + L(p) when -dfsan-combine-pointer-labels-on-load = true *p = b; L(*p) = L(b) when -dfsan-combine-pointer-labels-on-store = false L(*p) = L(b) + L(p) when -dfsan-combine-pointer-labels-on-store = true The question is what to do with p += c. In practice we found many confusing flows if we propagate labels from c to p. So a new flag works like this p += c; L(p) = L(p) when -dfsan-propagate-via-pointer-arithmetic = false L(p) = L(p) + L(c) when -dfsan-propagate-via-pointer-arithmetic = true Reviewed-by: gbalats Differential Revision: https://reviews.llvm.org/D103176
29 lines
745 B
C
29 lines
745 B
C
// RUN: %clang_dfsan %s -mllvm -dfsan-combine-offset-labels-on-gep=false -o %t && %run %t
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// RUN: %clang_dfsan %s -DPROP_OFFSET_LABELS -o %t && %run %t
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//
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// REQUIRES: x86_64-target-arch
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// Tests that labels are propagated through GEP.
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#include <sanitizer/dfsan_interface.h>
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#include <assert.h>
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int main(void) {
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int i = 1;
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int *p = &i;
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int j = 2;
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// test that pointer arithmetic propagates labels in terms of the flag.
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dfsan_set_label(1, &i, sizeof(i));
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p += i;
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#ifdef PROP_OFFSET_LABELS
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assert(dfsan_get_label(p) == 1);
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#else
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assert(dfsan_get_label(p) == 0);
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#endif
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// test that non-pointer operations always propagate labels.
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dfsan_set_label(2, &j, sizeof(j));
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j += i;
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assert(dfsan_get_label(j) == 3);
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return 0;
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}
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