maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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;
}