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[ubsan] Teach the pointer overflow check that "p - <unsigned> <= p" (compiler-rt) 

Compiler-rt changes associated with: D34121

llvm-svn: 307956
This commit is contained in:
Vedant Kumar 2017-07-13 20:55:41 +00:00
parent 175b6d1f28
commit 965f23fe84
2 changed files with 21 additions and 9 deletions
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15
compiler-rt/lib/ubsan/ubsan_handlers.cc
View File

@ -573,14 +573,19 @@ static void handlePointerOverflowImpl(PointerOverflowData *Data,
ScopedReport R(Opts, Loc, ET);
if ((sptr(Base) >= 0) == (sptr(Result) >= 0))
Diag(Loc, DL_Error, "unsigned pointer index expression result is %0, "
"preceding its base %1")
<< (void *)Result << (void *)Base;
else
if ((sptr(Base) >= 0) == (sptr(Result) >= 0)) {
if (Base > Result)
Diag(Loc, DL_Error, "addition of unsigned offset to %0 overflowed to %1")
<< (void *)Base << (void *)Result;
else
Diag(Loc, DL_Error,
"subtraction of unsigned offset from %0 overflowed to %1")
<< (void *)Base << (void *)Result;
} else {
Diag(Loc, DL_Error,
"pointer index expression with base %0 overflowed to %1")
<< (void *)Base << (void *)Result;
}
}
void __ubsan::__ubsan_handle_pointer_overflow(PointerOverflowData *Data,

15
compiler-rt/test/ubsan/TestCases/Pointer/unsigned-index-expression.cpp
View File

@ -1,13 +1,20 @@
// RUN: %clangxx -fsanitize=pointer-overflow %s -o %t
// RUN: %clangxx -std=c++11 -fsanitize=pointer-overflow %s -o %t
// RUN: %t 2>&1 | FileCheck %s
int main(int argc, char *argv[]) {
char c;
char *p = &c;
unsigned long long offset = -1;
unsigned long long neg_1 = -1;
// CHECK: unsigned-index-expression.cpp:[[@LINE+1]]:15: runtime error: unsigned pointer index expression result is 0x{{.*}}, preceding its base 0x{{.*}}
char *q = p + offset;
// CHECK: unsigned-index-expression.cpp:[[@LINE+1]]:15: runtime error: addition of unsigned offset to 0x{{.*}} overflowed to 0x{{.*}}
char *q = p + neg_1;
// CHECK: unsigned-index-expression.cpp:[[@LINE+1]]:16: runtime error: subtraction of unsigned offset from 0x{{.*}} overflowed to 0x{{.*}}
char *q1 = p - neg_1;
// CHECK: unsigned-index-expression.cpp:[[@LINE+2]]:16: runtime error: pointer index expression with base 0x{{0*}} overflowed to 0x{{.*}}
char *n = nullptr;
char *q2 = n - 1ULL;
return 0;
}