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Partial fix for PR 8015 (fix is actually by Jordy Rose, and I added a test case for follow-on work). This patch adds a bandaid for RegionStore's limited reasoning about symbolic array values. 

llvm-svn: 112766
This commit is contained in:
Ted Kremenek 2010-09-01 23:27:26 +00:00
parent 1b87c9a646
commit 0e12f9cc7b
2 changed files with 32 additions and 1 deletions
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7
clang/lib/Checker/RegionStore.cpp
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@ -1193,13 +1193,18 @@ SVal RegionStoreManager::RetrieveFieldOrElementCommon(Store store,
}
if (R->hasStackNonParametersStorage()) {
if (isa<ElementRegion>(R)) {
if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
// Currently we don't reason specially about Clang-style vectors. Check
// if superR is a vector and if so return Unknown.
if (const TypedRegion *typedSuperR = dyn_cast<TypedRegion>(superR)) {
if (typedSuperR->getValueType()->isVectorType())
return UnknownVal();
}
// FIXME: We also need to take ElementRegions with symbolic indexes into
// account.
if (!ER->getIndex().isConstant())
return UnknownVal();
}
return UndefinedVal();

26
clang/test/Analysis/misc-ps-region-store.m
View File

@ -1090,3 +1090,29 @@ pr8052(u_int boot_addr)
*dst++ = *src++;
}
// PR 8015 - don't return undefined values for arrays when using a valid
// symbolic index
int pr8015_A();
void pr8015_B(const char *);
void pr8015_C() {
int number = pr8015_A();
const char *numbers[] = { "zero" };
if (number == 0) {
pr8015_B(numbers[number]); // no-warning
}
}
// FIXME: This is a false positive due to not reasoning about symbolic
// array indices correctly. Discussion in PR 8015.
void pr8015_D_FIXME() {
int number = pr8015_A();
const char *numbers[] = { "zero" };
if (number == 0) {
if (numbers[number] == numbers[0])
return;
int *p = 0;
*p = 0xDEADBEEF; // expected-warning{{Dereference of null pointer}}
}
}