documentation) with one based on what GCC's __builtin_constant_p is actually
intended to do (discovered by asking a friendly GCC developer).
In particular, an expression which folds to a pointer is now only considered to
be a "constant" by this builtin if it refers to the first character in a string
literal.
This fixes a rather subtle wrong-code issue when building with glibc. Given:
const char cs[4] = "abcd";
int f(const char *p) { return strncmp(p, cs, 4); }
... the macro magic for strncmp produces a (potentially crashing) call to
strlen(cs), because it expands to an expression starting with:
__builtin_constant_p(cs) && strlen(cs) < 4 ? /* ... */
Under the secret true meaning of __builtin_constant_p, this is guaranteed to be
safe!
llvm-svn: 146236
bound to not have side effects(!). Add constant-folding support for expressions
of void type, to ensure that we can still fold ((void)0, 1) as an array bound.
llvm-svn: 146000
evaluator into constant initializer handling / IRGen. The practical consequence
of this is that the bitcast now lives in the constant's definition, rather than
in its uses.
The code in the constant expression evaluator was producing vectors of the wrong
type and size (and possibly of the wrong value for a big-endian int-to-vector
bitcast). We were getting away with this only because we don't yet support
constant-folding of any expressions which inspect vector values.
llvm-svn: 145981
semantics and defaults as the corresponding g++ arguments. The historical g++
argument -ftemplate-depth-N is kept for compatibility, but modern g++ versions
no longer document that option.
Add -cc1 argument -fconstexpr-depth N to implement the corresponding
functionality.
The -ftemplate-depth=N part of this fixes PR9890.
llvm-svn: 145045
or MemberExpr which refers to it. As a side-effect, MemberExprs which refer to
static member functions and static data members are now emitted as constant
expressions.
llvm-svn: 144468
reinstates r144273; a combination of r144333's fix for NoOp rvalue-to-lvalue
casts and some corresponding changes here resolve the regression which that
caused.
This patch also adds support for some additional forms of member function call,
along with additional testing.
llvm-svn: 144369
is currently too inefficient to allow us to use it for array initializers, but
fortunately we usually don't yet need to evaluate such initializers.
llvm-svn: 144260
expression evaluation:
- When folding a non-value-dependent expression, we may try to use the
initializer of a value-dependent variable. If that happens, give up.
- In C++98, actually check that a const, non-volatile DeclRefExpr inside an ICE
is of integral or enumeration type (a reference isn't OK!)
- In C++11, DeclRefExprs for objects of const literal type initialized with
value-dependent expressions are themselves value-dependent.
- So are references initialized with value-dependent expressions (though this
case is missing from the C++11 standard, along with many others).
llvm-svn: 144056
partially undoes the revert in r143491, but does not introduce any new instances
of the underlying issue (which is not yet fixed) in code which does not use
the 'constexpr' keyword.
llvm-svn: 143905
property references to use a new PseudoObjectExpr
expression which pairs a syntactic form of the expression
with a set of semantic expressions implementing it.
This should significantly reduce the complexity required
elsewhere in the compiler to deal with these kinds of
expressions (e.g. IR generation's special l-value kind,
the static analyzer's Message abstraction), at the lower
cost of specifically dealing with the odd AST structure
of these expressions. It should also greatly simplify
efforts to implement similar language features in the
future, most notably Managed C++'s properties and indexed
properties.
Most of the effort here is in dealing with the various
clients of the AST. I've gone ahead and simplified the
ObjC rewriter's use of properties; other clients, like
IR-gen and the static analyzer, have all the old
complexity *and* all the new complexity, at least
temporarily. Many thanks to Ted for writing and advising
on the necessary changes to the static analyzer.
I've xfailed a small diagnostics regression in the static
analyzer at Ted's request.
llvm-svn: 143867
to allow us to implement the C++11 rule that a non-active union member can't be
read, and use it to implement subobject access for string literals.
llvm-svn: 143677
just integers and floating point types. Since we don't support evaluating class
types or performing lvalue-to-rvalue conversions on array elements yet, this
just means pointer types right now.
llvm-svn: 143298
Track the function invocation where an lvalue referring to a constexpr function
parameter originated from, and use it to substitute the correct argument and to
determine whether such an argument's lifetime has ended.
llvm-svn: 143296
implicitly perform an lvalue-to-rvalue conversion if used on an lvalue
expression. Also improve the documentation of Expr::Evaluate* to indicate which
of them will accept expressions with side-effects.
llvm-svn: 143263
constexpr function arguments outside of their function (passing or returning
them by reference) does not work correctly yet.
Calling constexpr function templates does not work yet, since the bodies are not
instantiated until the end of the translation unit.
llvm-svn: 143234
are present in all the necessary places:
In constant expression evaluation, evaluate lvalues as lvalues and rvalues as
rvalues. Remove special case for caching reference initialization and fix a
cyclic initialization crash in the process.
llvm-svn: 143204
rvalues, as C++11 constant evaluation semantics require. DeclRefs referring to
references can now use the normal initialization-caching codepath, which
incidentally fixes a crash in cyclic initialization of references.
llvm-svn: 142844
- Remodel Expr::EvaluateAsInt to behave like the other EvaluateAs* functions,
and add Expr::EvaluateKnownConstInt to capture the current fold-or-assert
behaviour.
- Factor out evaluation of bitfield bit widths.
- Fix a few places which would evaluate an expression twice: once to determine
whether it is a constant expression, then again to get the value.
llvm-svn: 141561
Allow empty initializer lists for scalars, which mean value-initialization.
Constant evaluation for single-element and empty initializer lists for scalars.
Codegen for empty initializer lists for scalars.
Test case comes in next commit.
llvm-svn: 140459
the lifetime of the block by copying it to the heap, or else we'll get
a dangling reference because the code working with the non-block-typed
object will not know it needs to copy.
There is some danger here, e.g. with assigning a block literal to an
unsafe variable, but, well, it's an unsafe variable.
llvm-svn: 139451
than conversions of C pointers to ObjC pointers. In order to ensure that
we've caught every case, add asserts to CastExpr that strictly determine
which cast kind is used for which kind of bit cast.
llvm-svn: 139352
builtin types (When requested). This is another step toward making
ASTUnit build the ASTContext as needed when loading an AST file,
rather than doing so after the fact. No actual functionality change (yet).
llvm-svn: 138985
const int &x = x;
This crashed by inifinetly recursing within the lvalue evaluation
routine. I've added a (somewhat) braindead way of preventing this
recursion. If folks have better suggestions for how to avoid it I'm all
ears.
That said, we have some work to do. This doesn't trigger a single
warning for uninitialized, self-initialized or otherwise completely
wrong code. In some senses, the crash was almost better.
llvm-svn: 138239
to represent a fully-substituted non-type template parameter.
This should improve source fidelity, as well as being generically
useful for diagnostics and such.
llvm-svn: 135243
where we have an immediate need of a retained value.
As an exception, don't do this when the call is made as the immediate
operand of a __bridge retain. This is more in the way of a workaround
than an actual guarantee, so it's acceptable to be brittle here.
rdar://problem/9504800
llvm-svn: 134605
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>.
llvm-svn: 133521
Language-design credit goes to a lot of people, but I particularly want
to single out Blaine Garst and Patrick Beard for their contributions.
Compiler implementation credit goes to Argyrios, Doug, Fariborz, and myself,
in no particular order.
llvm-svn: 133103
__builtin_astype(): Used to reinterpreted as another data type of the same size using for both scalar and vector data types.
Added test case.
llvm-svn: 132612
that the unevaluated subexpressions of &&, ||, and ? : are not
considered when determining whether the expression is a constant
expression. Also, turn the "used in its own initializer" warning into
a runtime-behavior warning, so that it doesn't fire when a variable is
used as part of an unevaluated subexpression of its own initializer.
Fixes PR9999.
llvm-svn: 131968
Type::isUnsignedIntegerOrEnumerationType(), which are like
Type::isSignedIntegerType() and Type::isUnsignedIntegerType() but also
consider the underlying type of a C++0x scoped enumeration type.
Audited all callers to the existing functions, switching those that
need to also handle scoped enumeration types (e.g., those that deal
with constant values) over to the new functions. Fixes PR9923 /
<rdar://problem/9447851>.
llvm-svn: 131735
This introduces a generic base class for the expression evaluator
classes, which handles a few common expression types which were
previously handled separately in each class. Also, the expression
evaluator now uses ConstStmtVisitor.
llvm-svn: 131281
Patch authored by John Wiegley.
These are array type traits used for parsing code that employs certain
features of the Embarcadero C++ compiler: __array_rank(T) and
__array_extent(T, Dim).
llvm-svn: 130351
Patch authored by David Abrahams.
These two expression traits (__is_lvalue_expr, __is_rvalue_expr) are used for
parsing code that employs certain features of the Embarcadero C++ compiler.
llvm-svn: 130122
double data[20000000] = {0};
we would blow out the memory by creating 20M Exprs to fill out the initializer.
To fix this, if the initializer list initializes an array with more elements than
there are initializers in the list, have InitListExpr store a single 'ArrayFiller' expression
that specifies an expression to be used for value initialization of the rest of the elements.
Fixes rdar://9275920.
llvm-svn: 129896
for __unknown_anytype resolution to destructively modify the AST. So that's
what it does now, which significantly simplifies some of the implementation.
Normal member calls work pretty cleanly now, and I added support for
propagating unknown-ness through &.
llvm-svn: 129331
represents a dynamic cast where we know that the result is always null.
For example:
struct A {
virtual ~A();
};
struct B final : A { };
struct C { };
bool f(B* b) {
return dynamic_cast<C*>(b);
}
llvm-svn: 129256
The idea is that you can create a VarDecl with an unknown type, or a
FunctionDecl with an unknown return type, and it will still be valid to
access that object as long as you explicitly cast it at every use. I'm
still going back and forth about how I want to test this effectively, but
I wanted to go ahead and provide a skeletal implementation for the LLDB
folks' benefit and because it also improves some diagnostic goodness for
placeholder expressions.
llvm-svn: 129065
which versions of an OS provide a certain facility. For example,
void foo()
__attribute__((availability(macosx,introduced=10.2,deprecated=10.4,obsoleted=10.6)));
says that the function "foo" was introduced in 10.2, deprecated in
10.4, and completely obsoleted in 10.6. This attribute ties in with
the deployment targets (e.g., -mmacosx-version-min=10.1 specifies that
we want to deploy back to Mac OS X 10.1). There are several concrete
behaviors that this attribute enables, as illustrated with the
function foo() above:
- If we choose a deployment target >= Mac OS X 10.4, uses of "foo"
will result in a deprecation warning, as if we had placed
attribute((deprecated)) on it (but with a better diagnostic)
- If we choose a deployment target >= Mac OS X 10.6, uses of "foo"
will result in an "unavailable" warning (in C)/error (in C++), as
if we had placed attribute((unavailable)) on it
- If we choose a deployment target prior to 10.2, foo() is
weak-imported (if it is a kind of entity that can be weak
imported), as if we had placed the weak_import attribute on it.
Naturally, there can be multiple availability attributes on a
declaration, for different platforms; only the current platform
matters when checking availability attributes.
The only platforms this attribute currently works for are "ios" and
"macosx", since we already have -mxxxx-version-min flags for them and we
have experience there with macro tricks translating down to the
deprecated/unavailable/weak_import attributes. The end goal is to open
this up to other platforms, and even extension to other "platforms"
that are really libraries (say, through a #pragma clang
define_system), but that hasn't yet been designed and we may want to
shake out more issues with this narrower problem first.
Addresses <rdar://problem/6690412>.
As a drive-by bug-fix, if an entity is both deprecated and
unavailable, we only emit the "unavailable" diagnostic.
llvm-svn: 128127
class and to bind the shared value using OpaqueValueExpr. This fixes an
unnoticed problem with deserialization of these expressions where the
deserialized form would lose the vital pointer-equality trait; or rather,
it fixes it because this patch also does the right thing for deserializing
OVEs.
Change OVEs to not be a "temporary object" in the sense that copy elision is
permitted.
This new representation is not totally unawkward to work with, but I think
that's really part and parcel with the semantics we're modelling here. In
particular, it's much easier to fix things like the copy elision bug and to
make the CFG look right.
I've tried to update the analyzer to deal with this in at least some
obvious cases, and I think we get a much better CFG out, but the printing
of OpaqueValueExprs probably needs some work.
llvm-svn: 125744
there were only three virtual methods of any significance.
The primary way to grab child iterators now is with
Stmt::child_range children();
Stmt::const_child_range children() const;
where a child_range is just a std::pair of iterators suitable for
being llvm::tie'd to some locals. I've left the old child_begin()
and child_end() accessors in place, but it's probably a substantial
penalty to grab the iterators individually now, since the
switch-based dispatch is kindof inherently slower than vtable
dispatch. Grabbing them together is probably a slight win over the
status quo, although of course we could've achieved that with vtables, too.
I also reclassified SwitchCase (correctly) as an abstract Stmt
class, which (as the first such class that wasn't an Expr subclass)
required some fiddling in a few places.
There are somewhat gross metaprogramming hooks in place to ensure
that new statements/expressions continue to implement
getSourceRange() and children(). I had to work around a recent clang
bug; dgregor actually fixed it already, but I didn't want to
introduce a selfhosting dependency on ToT.
llvm-svn: 125183
that captures the substitution of a non-type template argument pack
for a non-type template parameter pack within a pack expansion that
cannot be fully expanded. This follows the approach taken by
SubstTemplateTypeParmPackType.
llvm-svn: 123506
template argument (described by an expression, of course). For
example:
template<int...> struct int_tuple { };
template<int ...Values>
struct square {
typedef int_tuple<(Values*Values)...> type;
};
It also lays the foundation for pack expansions in an initializer-list.
llvm-svn: 122751
new gcc warning that complains on self-assignments and
self-initializations. Fix one bug found by the warning, in which one
clang::OverloadCandidate constructor failed to initialize its
FunctionTemplate member.
llvm-svn: 122459
zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.
llvm-svn: 121121
implicit conversions; the last batch was specific to promotions.
I think this is the full set we need. I do think dividing the cast
kinds into floating and integral is probably a good idea.
Annotate a *lot* more C casts with useful cast kinds.
llvm-svn: 119036
own subcategory, -Wconstant-conversion, which is on by default.
Tweak the constant folder to give better results in the invalid
case of a negative shift amount.
Implements rdar://problem/6792488
llvm-svn: 118636
initializers, so the result of the evaluation doesn't leak through
inconsistently. Also, don't evaluate references to variables with
initializers with side-effects.
llvm-svn: 113128
The extra data stored on user-defined literal Tokens is stored in extra
allocated memory, which is managed by the PreprocessorLexer because there isn't
a better place to put it that makes sure it gets deallocated, but only after
it's used up. My testing has shown no significant slowdown as a result, but
independent testing would be appreciated.
llvm-svn: 112458
just means "not a function type", not "not a function type or void". This
changes behavior slightly, but generally in a way which accepts more code.
llvm-svn: 110303
Richard Smith