<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
to statically type various methods in SValuator/GRState as required either a
defined value or a defined-but-possibly-unknown value. This leads to various
logic cleanups in GRExprEngine, and lets the compiler enforce via type checking
our assumptions about what symbolic values are possibly undefined and what are
not.
Along the way, clean up some of the static analyzer diagnostics regarding the uses of uninitialized values.
llvm-svn: 81579
pointers. Most logic cares first about whether or not a region is
symbolic, and second if represents code. This should fix a series of
silent corner case bugs (as well as simplify a bunch of code).
llvm-svn: 80335
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
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
(1) Moved the SValuator object from GRExprEngine to ValueManager. This
allows ValueManager to use the SValuator when creating SVals.
(2) Added ValueManager::makeArrayIndex() and
ValueManager::convertToArrayIndex(), two SVal creation methods
that will help RegionStoreManager always have a consistent set of
SVals with the same integer size and type when reasoning about
array indices.
llvm-svn: 75882
SymbolDerived allows us to model symbolic values that are related to other
symbols via a region hierarchy. For example, SymbolDerived can be used to model
individual values of a symbolic array.
llvm-svn: 75728
Ted Kremenek