Don't try to map an APSInt addend to an int64_t in pointer arithmetic before
bounds-checking it. This gives more consistent behavior (outside C++11, we
consistently use 2s complement semantics for both pointer and integer overflow
in constant expressions) and fixes some cases where in C++11 we would fail to
properly check for out-of-bounds pointer arithmetic (if the 2s complement
64-bit overflow landed us back in-bounds).
In passing, also fix some cases where we'd perform possibly-overflowing
arithmetic on CharUnits (which have a signed underlying type) during constant
expression evaluation.
llvm-svn: 293595
This fixes various ways to tickle an assertion in constant expression
evaluation when using __int128. Longer term, we need to figure out what should
happen here: either any kind of overflow in offset calculation should result in
a non-constant value or we should truncate to 64 bits. In C++11 onwards, we're
effectively already checking for overflow because we strictly enforce array
bounds checks, but even there some forms of overflow can slip past undetected.
llvm-svn: 293568
Currently, the constexpr evaluator is very conservative about unmodeled
side-effects when we're evaluating an expression in a mode that allows
such side-effects.
This patch makes us note when we might have actually encountered an
unmodeled side-effect, which allows us to be more accurate when we know
an unmodeled side-effect couldn't have occurred.
This patch has been split into two commits; this one primarily
introduces the bits necessary to track whether we might have potentially
hit such a side-effect. The one that actually does the tracking (which
boils down to more or less a rename of keepEvaluatingAfterFailure to
noteFailure) is coming soon.
Differential Revision: http://reviews.llvm.org/D18540
llvm-svn: 270781
lists. Since the fields are inititalized one at a time, using a field with
lower index to initialize a higher indexed field should not be warned on.
llvm-svn: 218339
Introduce CXXStdInitializerListExpr node, representing the implicit
construction of a std::initializer_list<T> object from its underlying array.
The AST representation of such an expression goes from an InitListExpr with a
flag set, to a CXXStdInitializerListExpr containing a MaterializeTemporaryExpr
containing an InitListExpr (possibly wrapped in a CXXBindTemporaryExpr).
This more detailed representation has several advantages, the most important of
which is that the new MaterializeTemporaryExpr allows us to directly model
lifetime extension of the underlying temporary array. Using that, this patch
*drastically* simplifies the IR generation of this construct, provides IR
generation support for nested global initializer_list objects, fixes several
bugs where the destructors for the underlying array would accidentally not get
invoked, and provides constant expression evaluation support for
std::initializer_list objects.
llvm-svn: 183872
handle temporaries which have been lifetime-extended to static storage duration
within constant expressions. This correctly handles nested lifetime extension
(through reference members of aggregates in aggregate initializers) but
non-constant-expression emission hasn't yet been updated to do the same.
llvm-svn: 183283
The most common (non-buggy) case are where such objects are used as
return expressions in bool-returning functions or as boolean function
arguments. In those cases I've used (& added if necessary) a named
function to provide the equivalent (or sometimes negative, depending on
convenient wording) test.
DiagnosticBuilder kept its implicit conversion operator owing to the
prevalent use of it in return statements.
One bug was found in ExprConstant.cpp involving a comparison of two
PointerUnions (PointerUnion did not previously have an operator==, so
instead both operands were converted to bool & then compared). A test
is included in test/SemaCXX/constant-expression-cxx1y.cpp for the fix
(adding operator== to PointerUnion in LLVM).
llvm-svn: 181869
inefficient; we perform a linear scan of switch labels to find the one matching
the condition, and then walk the body looking for that label. Both parts should
be straightforward to optimize.
llvm-svn: 181671
statement in constexpr functions. Everything which doesn't require variable
mutation is also allowed as an extension in C++11. 'void' becomes a literal
type to support constexpr functions which return 'void'.
llvm-svn: 180022
Richard Smith