It makes it easier to discriminate between values of similar expressions
in different stack frames.
It also makes the separate backtrace section in ExplodedGraph dumps redundant.
Differential Revision: https://reviews.llvm.org/D42552
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The implementation is in AnalysisDeclContext.cpp and the class is called
AnalysisDeclContext.
Making those match up has numerous benefits, including:
- Easier jump from header to/from implementation.
- Easily identify filename from class.
Differential Revision: https://reviews.llvm.org/D37500
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SymbolReaper was destroying the symbol too early when it was referenced only
from an index SVal of a live ElementRegion.
In order to test certain aspects of this patch, extend the debug.ExprInspection
checker to allow testing SymbolReaper in a direct manner.
Differential Revision: http://reviews.llvm.org/D12726
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Summary:
`TypeTraitExpr`s are not supported by the ExprEngine today. Analyzer
creates a sink, and aborts the block. Therefore, certain bugs that
involve type traits intrinsics cannot be detected (see PR24710).
This patch creates boolean `SVal`s for `TypeTraitExpr`s, which are
evaluated by the compiler.
Test within the patch is a summary of PR24710.
Reviewers: zaks.anna, dcoughlin, krememek
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D12482
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(return by value is in ExprEngine::processPointerEscapedOnBind and any
other call to the scanReachableSymbols function template used there)
Protect the special members in the base class to avoid slicing, and make
derived classes final so these special members don't accidentally become
public on an intermediate base which would open up the possibility of
slicing again.
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will never be true in a well-defined context. The checking for null pointers
has been moved into the caller logic so it does not rely on undefined behavior.
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Previously, this was scattered across Environment (literal expressions),
ExprEngine (default arguments), and RegionStore (global constants). The
former special-cased several kinds of simple constant expressions, while
the latter two deferred to the AST's constant evaluator.
Now, these are all unified as SValBuilder::getConstantVal(). To keep
Environment fast, the special cases for simple constant expressions have
been left in, but the main benefits are that (a) unusual constants like
ObjCStringLiterals now work as default arguments and global constant
initializers, and (b) we're not duplicating code between ExprEngine and
RegionStore.
This actually caught a bug in our test suite, which is awesome: we stop
tracking allocated memory if it's passed as an argument along with some
kind of callback, but not if the callback is 0. We were testing this in
a case where the callback parameter had a default value, but that value
was 0. After this change, the analyzer now (correctly) flags that as a
leak!
<rdar://problem/13773117>
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Previously, we were handling only simple integer constants for globals and
the smattering of implicitly-valued expressions handled by Environment for
default arguments. Now, we can use any integer constant expression that
Clang can evaluate, in addition to everything we handled before.
PR15094 / <rdar://problem/12830437>
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This feature was probably intended to improve diagnostics, but was currently
only used when dumping the Environment. It shows what location a given value
was loaded from, e.g. when evaluating an LValueToRValue cast.
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This allows us to properly remove dead bindings at the end of the top-level
stack frame, using the ReturnStmt, if there is one, to keep the return value
live. This in turn removes the need for a check::EndPath callback in leak
checkers.
This does cause some changes in the path notes for leak checkers. Previously,
a leak would be reported at the location of the closing brace in a function.
Now, it gets reported at the last statement. This matches the way leaks are
currently reported for inlined functions, but is less than ideal for both.
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This actually looks through several kinds of expression, such as
OpaqueValueExpr and ExprWithCleanups. The idea is that binding and lookup
should be consistent, and so if the environment needs to be modified later,
the code doing the modification will not have to manually look through these
"transparent" expressions to find the real binding to change.
This is necessary for proper updating of struct rvalues as described in
the previous commit.
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This was only used by OSAtomicChecker and makes it more
difficult to update values for expressions that the environment
may look through instead (it's not the same as IgnoreParens).
With this gone, we can have bindExpr bind to the inner
expression that getSVal will find.
Groundwork for <rdar://problem/12137950>
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A CXXDefaultArgExpr wraps an Expr owned by a ParmVarDecl belonging to the
called function. In general, ExprEngine and Environment ought to treat this
like a ParenExpr or other transparent wrapper expression, with the inside
expression evaluated first.
However, if we call the same function twice, we'd produce a CFG that contains
the same wrapped expression twice, and we're not set up to handle that. I've
added a FIXME to the CFG builder to come back to that, but meanwhile we can
at least handle expressions that don't need to be explicitly evaluated:
literals. This probably handles many common uses of default parameters:
true/false, null, etc.
Part of PR13385 / <rdar://problem/12156507>
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We were treating this like a CXXDefaultArgExpr, but
SubstNonTypeTemplateParmExpr actually appears when a template is
instantiated, i.e. we have all the information necessary to evaluate it.
This allows us to inline functions like llvm::array_lengthof.
<rdar://problem/11949235>
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ObjC properties are handled through their semantic form of ObjCMessageExprs
and their wrapper PseudoObjectExprs, and have been for quite a while. The
syntactic ObjCPropertyRefExprs do not appear in the CFG and are not visited
by ExprEngine.
No functionality change.
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At this point this is largely cosmetic, but it opens the door to replace
ProgramStateRef with a smart pointer that more eagerly acts in the role
of reclaiming unused ProgramState objects.
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My hope is to reimplement this from first principles based on the simplifications of removing unneeded node builders
and re-evaluating how C++ calls are handled in the CFG. The hope is to turn inlining "on-by-default" as soon as possible
with a core set of things working well, and then expand over time.
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(Stmt*,LocationContext*) pairs to SVals instead of Stmt* to SVals.
This is needed to support basic IPA via inlining. Without this, we cannot tell
if a Stmt* binding is part of the current analysis scope (StackFrameContext) or
part of a parent context.
This change introduces an uglification of the use of getSVal(), and thus takes
two steps forward and one step back. There are also potential performance implications
of enlarging the Environment. Both can be addressed going forward by refactoring the
APIs and optimizing the internal representation of Environment. This patch
mainly introduces the functionality upon when we want to build upon (and clean up).
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Pull out the declaration of the ScanReachableSymbols so that it can be used directly. Document ProgramState::scanReachableSymbols() methods.
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The motivation of this large change is to drastically simplify the logic in ExprEngine going forward.
Some fallout is that the output of some BugReporterVisitors is not as accurate as before; those will
need to be fixed over time. There is also some possible performance regression as RemoveDeadBindings
will be called frequently; this can also be improved over time.
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MaterializeTemporaryExpr captures a reference binding to a temporary
value, making explicit that the temporary value (a prvalue) needs to
be materialized into memory so that its address can be used. The
intended AST invariant here is that a reference will always bind to a
glvalue, and MaterializeTemporaryExpr will be used to convert prvalues
into glvalues for that binding to happen. For example, given
const int& r = 1.0;
The initializer of "r" will be a MaterializeTemporaryExpr whose
subexpression is an implicit conversion from the double literal "1.0"
to an integer value.
IR generation benefits most from this new node, since it was
previously guessing (badly) when to materialize temporaries for the
purposes of reference binding. There are likely more refactoring and
cleanups we could perform there, but the introduction of
MaterializeTemporaryExpr fixes PR9565, a case where IR generation
would effectively bind a const reference directly to a bitfield in a
struct. Addresses <rdar://problem/9552231>.
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Also, have Environment stop looking through NoOp casts; it didn't match the behavior of LiveVariables. And once that's gone, the whole cast block of that switch is unnecessary.
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George Karpenkov