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Fix another false positive in RegionStore involving doing loads from symbolic offsets. We still don't 

properly reason about such accesses, but we shouldn't emit bogus "uninitialized value" warnings
either.  Fixes <rdar://problem/11127008>.

llvm-svn: 153913
This commit is contained in:
Ted Kremenek 2012-04-03 00:03:34 +00:00
parent b495562b5d
commit b75f4e5e9b
2 changed files with 34 additions and 7 deletions
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25
clang/lib/StaticAnalyzer/Core/RegionStore.cpp
View File

@ -1194,14 +1194,23 @@ SVal RegionStoreManager::getBindingForFieldOrElementCommon(Store store,
// At this point we have already checked in either getBindingForElement or
// getBindingForField if 'R' has a direct binding.
RegionBindings B = GetRegionBindings(store);
// Record whether or not we see a symbolic index. That can completely
// be out of scope of our lookup.
bool hasSymbolicIndex = false;
while (superR) {
if (const Optional<SVal> &D =
getBindingForDerivedDefaultValue(B, superR, R, Ty))
return *D;
if (const ElementRegion *ER = dyn_cast<ElementRegion>(superR)) {
NonLoc index = ER->getIndex();
if (!index.isConstant())
hasSymbolicIndex = true;
}
// If our super region is a field or element itself, walk up the region
// hierarchy to see if there is a default value installed in an ancestor.
if (const SubRegion *SR = dyn_cast<SubRegion>(superR)) {
@ -1220,7 +1229,7 @@ SVal RegionStoreManager::getBindingForFieldOrElementCommon(Store store,
return getLazyBinding(lazyBindingRegion, lazyBindingStore);
if (R->hasStackNonParametersStorage()) {
if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
if (isa<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 TypedValueRegion *typedSuperR =
@ -1228,13 +1237,15 @@ SVal RegionStoreManager::getBindingForFieldOrElementCommon(Store store,
if (typedSuperR->getValueType()->isVectorType())
return UnknownVal();
}
// FIXME: We also need to take ElementRegions with symbolic indexes into
// account.
if (!ER->getIndex().isConstant())
return UnknownVal();
}
// FIXME: We also need to take ElementRegions with symbolic indexes into
// account. This case handles both directly accessing an ElementRegion
// with a symbolic offset, but also fields within an element with
// a symbolic offset.
if (hasSymbolicIndex)
return UnknownVal();
return UndefinedVal();
}

16
clang/test/Analysis/misc-ps-region-store.m
View File

@ -1325,3 +1325,19 @@ void rdar9444714() {
*dst = '\0';
}
// Test handling symbolic elements with field accesses.
// <rdar://problem/11127008>
typedef struct {
unsigned value;
} RDar11127008;
signed rdar_11127008_index();
static unsigned rdar_11127008(void) {
RDar11127008 values[] = {{.value = 0}, {.value = 1}};
signed index = rdar_11127008_index();
if (index < 0) return 0;
if (index >= 2) return 0;
return values[index].value;
}