RegionStoreManager::Retrieve() that was intended to handle conflated uses of pointers as integers.
It turns out this isn't needed, and resulted in inconsistent behavior when creating symbolic values on the following test case in 'tests/Analysis/misc-ps.m':
typedef struct _BStruct { void *grue; } BStruct;
void testB_aux(void *ptr);
void testB(BStruct *b) {
{
int *__gruep__ = ((int *)&((b)->grue));
int __gruev__ = *__gruep__;
testB_aux(__gruep__);
}
{
int *__gruep__ = ((int *)&((b)->grue));
int __gruev__ = *__gruep__;
if (~0 != __gruev__) {}
}
}
When the code was analyzed with '-arch x86_64', the value assigned to '__gruev__' be would be a
symbolic integer, but for '-arch i386' the value assigned to '__gruev__' would be a symbolic region
(a blob of memory). With this change the value created is always a symbolic integer.
Since the code being removed was added to support analysis of code calling
OSAtomicCompareAndSwapXXX(), I also modified 'test/Analysis/NSString.m' to analyze the code in both
'-arch i386' and '-arch x86_64', and also added some complementary test cases to test the presence
of leaks when using OSAtomicCompareAndSwap32Barrier()/OSAtomicCompareAndSwap64Barrier() instead of
just their absence. This code change reveals that previously both RegionStore and BasicStore were
handling these cases wrong, and would never cause the analyzer to emit a leak in these cases (false
negatives). Now RegionStore gets it right, but BasicStore still gets it wrong (and hence it has been
disabled temporarily for this test case).
llvm-svn: 84163
default binding for regions. This allows us to simply a lot of code. A
further simplification could be done is that many methods of
regionstore can only work on Store instead of GRState.
llvm-svn: 83762
adding assert
This fix required a few changes:
SimpleSValuator:
- Eagerly replace a symbolic value with its constant value in EvalBinOpNN
when it is constrained to a constant. This allows us to better constant fold
values along a path.
- Handle trivial case of '<', '>' comparison of pointers when the two pointers
are exactly the same.
RegionStoreManager:
llvm-svn: 83358
concrete types. Use unqualified desugaring for getAs<> and sundry.
Fix a few users to either not desugar or use qualified desugar, as seemed
appropriate. Removed Type's qualified desugar method, as it was easy
to accidentally use instead of QualType's.
llvm-svn: 83116
identified with a false positive reported by Thomas Clement. This
involved doing another rewrite of
RegionStoreManager::RemoveDeadBindings(), which phrases the entire
problem of scanning for dead regions as a graph exploration problem.
It is more methodic than the previous implementation.
llvm-svn: 83053
are only specially treated by RegionStore::InvalidateRegion() when
their super region is also invalidated. When this isn't the case,
conjure a new symbol for a FieldRegion. Thanks to Zhongxing Xu and
Daniel Dunbar for pointing out this issue.
llvm-svn: 83043
<rdar://problem/6914474> checker doesn't realize that variable might
have been assigned if a pointer to that variable was passed to another
function via a structure
The problem here was the RegionStoreManager::InvalidateRegion didn't
invalidate the bindings of invalidated regions. This required a
rewrite of this method using a worklist.
As part of this fix, changed ValueManager::getConjuredSymbolVal() to
require a 'void*' SymbolTag argument. This tag is used to
differentiate two different symbols created at the same location.
llvm-svn: 82920
The issue was a discrepancy between how RegionStoreManager::Bind() and
RegionStoreManager::Retrieve() derived the "key" for the first element
of a symbolic region.
llvm-svn: 82680
Several of the existing methods were identical to their respective
specializations, and so have been removed entirely. Several more 'leaf'
optimizations were introduced.
The getAsFoo() methods which imposed extra conditions, like
getAsObjCInterfacePointerType(), have been left in place.
llvm-svn: 82501
integer pointer. For now just invalidate the fields of the struct.
This addresses: <rdar://problem/7185607> [RegionStore] support invalidation of bit fields using integer assignment
llvm-svn: 82492
implicit cast logic in RegionStoreManager to BasicStoreManager. This involved
moving CastRetriedVal from RegionStoreManager to StoreManager.
llvm-svn: 80026
SelfRegion represented the object bound to 'self' (when analyzing Objective-C
methods) upon entry to a method. Having this region stored on the side ignores
the current stack frame that we might be analyzing (among other things), and is
a problem for interprocedural analysis.
For RegionStoreManager, the value for SelfRegion is just lazily created.
For BasicStoreManager, the value for SelfRegion is bound eagerly to 'self', but
no explicit tracking of SelfRegion on the side is made.
As part of this change, remove the restriction in BasicStoreManager that we only
track ivars for 'self'. This shouldn't actually change anything in terms of
precision, and simplifies the logic.
llvm-svn: 79694
with array accesses. In the process, refactor some common logic in
RetrieveElement() and RetrieveField() into RetrieveFieldOrElementCommon().
llvm-svn: 78349
RegionStore already lazily abstracted the contents of arrays and structs, when
doing an assignment from one array/struct to another we did an explicit
element-wise copy, which resulted in a loss of laziness and huge performance
problem when analyzing many code bases.
Now RegionStoreManager handles such assignments using a new SVal could
'LazyCompoundSVal', which basically means the value of a given struct or array
(a MemRegion*) in a specific state (GRState). When we do a load from a field
whose encompassing struct binds to a LazyCompoundSVal, we essentially do a field
lookup in the original structure. This means we have essentially zero copying of
data for structs/arrays and everything stays lazy.
llvm-svn: 78268
made to RegionStore (and related classes) in order to handle some
analyzer failures involving casts and manipulation of symbolic memory.
The root of the change is in StoreManager::CastRegion(). Instead of
using ad hoc heuristics to decide when to layer an ElementRegion on a
casted MemRegion, we now always layer an ElementRegion when the cast
type is different than the original type of the region. This carries
the current cast information associated with a region around without
resorting to the error prone recording of "casted types" in GRState.
Along with this new policy of layering ElementRegions, I added a new
algorithm to strip away existing ElementRegions when they simply
represented casts of a base memory object. This algorithm computes
the raw "byte offset" that an ElementRegion represents from the base
region, and allows the new ElementRegion to be based off that offset.
The added benefit is that this naturally handles a series of casts of
a MemRegion without building up a set of redundant ElementRegions
(thus canonicalizing the region view).
Other related changes that cascaded from this one (as tests were
failing in RegionStore):
- Revamped RegionStoreManager::InvalidateRegion() to completely remove
all bindings and default values from a region and all subregions.
Now invalidated fields are not bound directly to new symbolic
values; instead the base region has a "default" symbol value from
which "derived symbols" can be created. The main advantage of this
approach is that it allows us to invalidate a region hierarchy and
then lazily instantiate new values no matter how deep the hierarchy
went (i.e., regardless of the number of field accesses,
e.g. x->f->y->z->...). The previous approach did not do this.
- Slightly reworked RegionStoreManager::RemoveDeadBindings() to also
incorporate live symbols and live regions that do not have direct
bindings but also have "default values" used for lazy instantiation.
The changes to 'InvalidateRegion' revealed that these were necessary
in order to achieve lazy instantiation of values in the region store
with those bindings being removed too early.
- The changes to InvalidateRegion() and RemoveDeadBindings() revealed
a serious bug in 'getSubRegionMap()' where not all region -> subregion
relationships involved in actually bindings (explicit and implicit)
were being recorded. This has been fixed by using a worklist algorithm
to iteratively fill in the region map.
- Added special support to RegionStoreManager::Bind()/Retrieve() to handle
OSAtomicCompareAndSwap in light of the new 'CastRegion' changes and the
layering of ElementRegions.
- Fixed a bug in SymbolReaper::isLive() where derived symbols were not
being marked live if the symbol they were derived from was also live.
This fix was critical for getting lazy instantiation in RegionStore
to work.
- Tidied up the implementation of ValueManager::getXXXSymbolVal() methods
to use SymbolManager::canSymbolicate() to decide whether or not a
symbol should be symbolicated.
- 'test/Analysis/misc-ps-xfail.m' now passes; that test case has been
moved to 'test/Analysis/misc-ps.m'.
- Tweaked some pretty-printing of MemRegions, and implemented
'ElementRegion::getRawOffset()' for use with the CastRegion changes.
llvm-svn: 77782
Type::getAsReferenceType() -> Type::getAs<ReferenceType>()
Type::getAsRecordType() -> Type::getAs<RecordType>()
Type::getAsPointerType() -> Type::getAs<PointerType>()
Type::getAsBlockPointerType() -> Type::getAs<BlockPointerType>()
Type::getAsLValueReferenceType() -> Type::getAs<LValueReferenceType>()
Type::getAsRValueReferenceType() -> Type::getAs<RValueReferenceType>()
Type::getAsMemberPointerType() -> Type::getAs<MemberPointerType>()
Type::getAsReferenceType() -> Type::getAs<ReferenceType>()
Type::getAsTagType() -> Type::getAs<TagType>()
And remove Type::getAsReferenceType(), etc.
This change is similar to one I made a couple weeks ago, but that was partly
reverted pending some additional design discussion. With Doug's pending smart
pointer changes for Types, it seemed natural to take this approach.
llvm-svn: 77510
in StoreManager to RegionStoreManager, and create a special, highly reduced
version in BasicStoreManager.
These changes are in preparation for future RegionStore-specific changes to
InvalidateRegion.
llvm-svn: 77483
instead preferring to use the a region's actual type when creating
symbols and using the QualType passed to Retrieve for implicit
casting. This preprocessor logic is temporary; eventually we will
either remove region casts or keep them.
Temporarily toggle (via preprocessor directives) that SymbolicRegions
with heap storage are not undefined, but instead should be
symbolicated. If we want to model that a SymbolicRegion is
uninitialized, we can explicitly model that by binding UndefinedVal to
that region. It turns out that we want to treat most heap objects as
being defined, not the other way around.
llvm-svn: 76720
to SValuator::EvalCast. In the process, the StoreManagers now use this new cast
machinery, and the hack in GRExprEngine::EvalBind to handle implicit casts
involving OSAtomicCompareAndSwap and friends has been removed (and replaced with
logic closer to the logic specific to those functions).
llvm-svn: 76641
-refactor logic for retrieving bindings from VarDecls into
RegionStoreManager::RetrieveVar()
- improve RegionStoreManager::CastRetrievedVal() and SimpleSValuate::EvalCastNL
to better handle casts of values of the same canonical type as well as
casts of LocAsInteger values.
llvm-svn: 76516
