This change was a lot bigger than I originally anticipated; among
other things it requires us storing more information in the CFG to
record what block-level expressions need to be evaluated as lvalues.
The big change is that CFGBlocks no longer contain Stmt*'s by
CFGElements. Currently CFGElements just wrap Stmt*, but they also
store a bit indicating whether the block-level expression should be
evalauted as an lvalue. DeclStmts involving the initialization of a
reference require us treating the initialization expression as an
lvalue, even though that information isn't recorded in the AST.
Conceptually this change isn't that complicated, but it required
bubbling up the data through the CFGBuilder, to GRCoreEngine, and
eventually to GRExprEngine.
The addition of CFGElement is also useful for when we want to handle
more control-flow constructs or other data we want to keep in the CFG
that isn't represented well with just a block of statements.
In GRExprEngine, this patch introduces logic for evaluating the
lvalues of references, which currently retrieves the internal "pointer
value" that the reference represents. EvalLoad does a two stage load
to catch null dereferences involving an invalid reference (although
this could possibly be caught earlier during the initialization of a
reference).
Symbols are currently symbolicated using the reference type, instead
of a pointer type, and special handling is required creating
ElementRegions that layer on SymbolicRegions (see the changes to
RegionStoreManager).
Along the way, the DeadStoresChecker also silences warnings involving
dead stores to references. This was the original change I introduced
(which I wrote test cases for) that I realized caused GRExprEngine to
crash.
llvm-svn: 91501
- Refactor the MemRegion hierarchy to distinguish between different StackSpaceRegions for locals and parameters.
- VarRegions for "captured" variables now have the BlockDataRegion as their super region (except those passed by reference)
- Add transfer function support to GRExprEngine for BlockDeclRefExprs.
This change also supports analyzing blocks as an analysis entry point
(top-of-the-stack), which required pushing more context-sensitivity
around in the MemRegion hierarchy via the use of LocationContext
objects. Functionally almost everything is the same, except we track
LocationContexts in a few more areas and StackSpaceRegions now refer
to a StackFrameContext object. In the future we will need to modify
MemRegionManager to allow multiple StackSpaceRegions in flight at once
(for the analysis of multiple stack frames).
llvm-svn: 90809
sugared types. The basic problem is that our qualifier accessors
(getQualifiers, getCVRQualifiers, isConstQualified, etc.) only look at
the current QualType and not at any qualifiers that come from sugared
types, meaning that we won't see these qualifiers through, e.g.,
typedefs:
typedef const int CInt;
typedef CInt Self;
Self.isConstQualified() currently returns false!
Various bugs (e.g., PR5383) have cropped up all over the front end due
to such problems. I'm addressing this problem by splitting each
qualifier accessor into two versions:
- the "local" version only returns qualifiers on this particular
QualType instance
- the "normal" version that will eventually combine qualifiers from this
QualType instance with the qualifiers on the canonical type to
produce the full set of qualifiers.
This commit adds the local versions and switches a few callers from
the "normal" version (e.g., isConstQualified) over to the "local"
version (e.g., isLocalConstQualified) when that is the right thing to
do, e.g., because we're printing or serializing the qualifiers. Also,
switch a bunch of
Context.getCanonicalType(T1).getUnqualifiedType() == Context.getCanonicalType(T2).getQualifiedType()
expressions over to
Context.hasSameUnqualifiedType(T1, T2)
llvm-svn: 88969
* Add a load type to GRExprEngine::EvalLoad().
* When retrieve from 'theValue' of OSAtomic funcitions, use the type of the
region instead of the argument expression as the load type.
* Then we can convert CastRetrievedSVal to a pure assertion. In the future
we can let all Retrieve() methods simply return SVal.
llvm-svn: 88888
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
implicit cast logic in RegionStoreManager to BasicStoreManager. This involved
moving CastRetriedVal from RegionStoreManager to StoreManager.
llvm-svn: 80026
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
'cast type' of a region to invalidate its binding. This only occurs
when using RegionStoreManager, as it records the cast type. I'm
currently considering removing the notion of a cast type (see
comments in code).
llvm-svn: 76719
until Doug Gregor's Type smart pointer code lands (or more discussion occurs).
These methods just call the new Type::getAs<XXX> methods, so we still have
reduced implementation redundancy. Having explicit getAsXXXType() methods makes
it easier to set breakpoints in the debugger.
llvm-svn: 76193
This method is intended to eventually replace the individual
Type::getAsXXXType<> methods.
The motivation behind this change is twofold:
1) Reduce redundant implementations of Type::getAsXXXType() methods. Most of
them are basically copy-and-paste.
2) By centralizing the implementation of the getAs<Type> logic we can more
smoothly move over to Doug Gregor's proposed canonical type smart pointer
scheme.
Along with this patch:
a) Removed 'Type::getAsPointerType()'; now clients use getAs<PointerType>.
b) Removed 'Type::getAsBlockPointerTypE()'; now clients use getAs<BlockPointerType>.
llvm-svn: 76098
This patch causes:
- StoreManager::InvalidateRegion() to not used the casted type of a region if
it would cause a pointer type to be invalidated as a non-pointer type.
- Pushes RegionStore::RetrieveElement() further by handling retrievals from
symbolic arrays that have been invalidated. This uses the new SymbolDerived
construct that was recently introduced.
The result is that the failing test in misc-ps-region-store-x86_64.m now passes.
Both misc-ps-region-store-x86_64.m and misc-ps-region-store-i386.m contain a
test case that motivated this change.
llvm-svn: 75730
invalidate the region correctly. It uses the cast-to type to invalidate
the region when available. To avoid invalid cast-to type like 'void*' or 'id',
region store now only records non-generic casts of regions.
llvm-svn: 75580
CodeTextRegions can only be casted to FunctionPointer or BlockPointerTypes. This
simply isn't true. We can handle bogus operations on CodeTextRegions (e.g, an
array access) elsewhere.
llvm-svn: 75285
- Refactor logic that creates ElementRegions into a help method 'MakeElementRegion'.
- Fix crash due to not handling StringRegions. Casts of StringRegions now
result in a new ElementRegion layered on the original StringRegion.
llvm-svn: 74867
(its superclass). This will allow us to experiment with using the new CastRegion
with BasicStoreManager, and gradually phase out the old implementation.
llvm-svn: 74851
TypedRegion. While we plan on removing this code at some point, it serves as a
good reference implementation for use with BasicStore until we are sure the new
CastRegion logic (in RegionStore.cpp) is correct.
llvm-svn: 74559
Ted Kremenek