__builtin_object_size with incomplete array type in struct
The commit r316245 introduced a regression that causes an assertion failure when
Clang tries to cast an IncompleteArrayType to a PointerType when evaluating
__builtin_object_size.
rdar://36094951
Differential Revision: https://reviews.llvm.org/D41405
llvm-svn: 321222
Adding the new enumerator forced a bunch more changes into this patch than I
would have liked. The -Wtautological-compare warning was extended to properly
check the new comparison operator, clang-format needed updating because it uses
precedence levels as weights for determining where to break lines (and several
operators increased their precedence levels with this change), thread-safety
analysis needed changes to build its own IL properly for the new operator.
All "real" semantic checking for this operator has been deferred to a future
patch. For now, we use the relational comparison rules and arbitrarily give
the builtin form of the operator a return type of 'void'.
llvm-svn: 320707
C++14 [dcl.constexpr]p4 states that in the body of a constexpr
constructor,
> every non-variant non-static data member and base class sub-object
shall be initialized
However, [class.bit]p2 notes that
> Unnamed bit-fields are not members and cannot be initialized.
Therefore, we should make sure to filter them out of the check that
all fields are initialized.
Fixing this makes the constant evaluator a bit smarter, and
specifically allows constexpr constructors to avoid tripping
-Wglobal-constructors when the type contains unnamed bitfields.
Reviewed at https://reviews.llvm.org/D39035.
llvm-svn: 316408
constant expressions.
We permit array-to-pointer decay on such arrays, but disallow pointer
arithmetic (since we do not know whether it will have defined behavior).
This is based on r311970 and r301822 (the former by me and the latter by Robert
Haberlach). Between then and now, two things have changed: we have committee
feedback indicating that this is indeed the right direction, and the code
broken by this change has been fixed.
This is necessary in C++17 to continue accepting certain forms of non-type
template argument involving arrays of unknown bound.
llvm-svn: 316245
The standard is not clear on how these are supposed to be handled, so we
conservatively treat as non-constant any cases whose value is unknown or whose
evaluation might result in undefined behavior.
llvm-svn: 311970
When r310905 moved the pointer and bool out of a PointerIntPair, it made
them end up uninitialized and caused UBSan failures when copying the
uninitialized boolean. However, making the pointer be null should avoid
the reference to the boolean entirely.
llvm-svn: 310994
They are stack allocated, so their alignment is not to be trusted.
32-bit MSVC only guarantees 4 byte stack alignment, even though alignof
would tell you otherwise. I tried fixing this with __declspec align, but
that apparently upsets GCC. Hopefully this version will satisfy all
compilers.
See PR32018 for some info about the mingw issues.
Should supercede https://reviews.llvm.org/D34873
llvm-svn: 310905
Summary:
r306137 made dllimport pointers to member functions non-constant. This
is correct because a load must be executed to resolve any dllimported
data. However, r306137 did not account for the use of dllimport member
function pointers used as template arguments.
This change re-lands r306137 with a template instantiation fix.
This fixes PR33570.
Reviewers: rnk, majnemer
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D34714
llvm-svn: 307446
Also add testcases for a bunch of expression forms that cause our evaluator to
crash. See PR33140 and PR32864 for crashes that this was causing.
This reverts r305287, which reverted r305239, which reverted r301742. The
previous revert claimed that buildbots were broken, but did not add any
testcases and the buildbots have lost all memory of what was wrong here.
Changes to test/OpenMP are not reverted; another change has triggered those
tests to change their output in the same way that r301742 did.
llvm-svn: 306346
This reverts commit r306137. It has problems on code like this:
struct __declspec(dllimport) Foo {
int a;
int get_a() { return a; }
};
template <int (Foo::*Getter)()> struct HasValue {
int operator()(Foo *p) { return (p->*Getter)(); }
};
int main() {
Foo f;
f.a = 3;
int x = HasValue<&Foo::get_a>()(&f);
}
llvm-svn: 306175
We were already applying the same rules to dllimport function pointers.
David Majnemer added that logic back in r211677 to fix PR20130. We
failed to extend that logic to non-virtual member function pointers,
which are basically function pointers in a struct with some extra
offsets.
Fixes PR33570.
llvm-svn: 306137
We were leaving the SubobjectDesignator in a surprising situation, where
it was allegedly valid but didn't actually refer to a type. This caused
a crash later on.
This patch fills out the SubobjectDesignator with the pointee type (as
happens in other evaluations of constant pointers) so that we don't
crash later.
llvm-svn: 303957
handling of constexprs with unknown bounds.
This triggers a corner case of the language where it's not yet clear
whether this should be an error:
struct A {
static void *const a[];
static void *const b[];
};
constexpr void *A::a[] = {&b[0]};
constexpr void *A::b[] = {&a[0]};
When discovering the initializer for A::a, the bounds of A::b aren't known yet.
It is unclear whether warning about errors should be deferred until the end of
the translation unit, possibly resolving errors that can be resolved. In
practice, the compiler can know the bounds of all arrays in this example.
Credits for reproducers and explanation go to Richard Smith. Richard, please
add more info in case my explanation is wrong.
llvm-svn: 301963
The fix is that ExprEvaluatorBase::VisitInitListExpr should handle transparent exprs instead of exprs with one element. Fixing that uncovers one testcase failure because the AST for "constexpr _Complex float test2 = {1};" is wrong (the _Complex prvalue should not be const-qualified), and a number of test failures in test/OpenMP where the captured stmt contains an InitListExpr that is in syntactic form.
llvm-svn: 301891
Do not spuriously reject constexpr functions that access elements of an array
of unknown bound; this may later become valid once the bound is known. Permit
array-to-pointer decay on such arrays, but disallow pointer arithmetic (since
we do not know whether it will have defined behavior).
The standard is not clear on how this should work, but this seems to be a
decent answer.
Patch by Robert Haberlach!
llvm-svn: 301822
CheckForIntOverflow used to implement a whitelist of top-level expressions to
send to the constant expression evaluator, which handled many more expressions
than the CheckForIntOverflow whitelist did.
llvm-svn: 301742
A boxed expression evaluates its subexpr and then calls an objc method to transform it into another value with pointer type. The objc method can never be constexpr and therefore this expression can never be evaluated. Fixes a miscompile boxing expressions with side-effects.
Also make ObjCBoxedExpr handling a normal part of the expression evaluator instead of being the only case besides full-expression where we check for integer overflow.
llvm-svn: 301721
This patch honors the unaligned type qualifier (currently available through he
keyword __unaligned and -fms-extensions) in CodeGen. In the current form the
patch affects declarations and expressions. It does not affect fields of
classes.
Differential Revision: https://reviews.llvm.org/D30166
llvm-svn: 297276
Summary:
The changes contained in this patch are:
1. Defines a new AST node `CoawaitDependentExpr` for representing co_await expressions while the promise type is still dependent.
2. Correctly detect and transform the 'co_await' operand to `p.await_transform(<expr>)` when possible.
3. Change the initial/final suspend points to build during the initial parse, so they have the correct operator co_await lookup results.
4. Fix transformation of the CoroutineBodyStmt so that it doesn't re-build the final/initial suspends.
@rsmith: This change is a little big, but it's not trivial for me to split it up. Please let me know if you would prefer this submitted as multiple patches.
Reviewers: rsmith, GorNishanov
Reviewed By: rsmith
Subscribers: ABataev, rsmith, mehdi_amini, cfe-commits
Differential Revision: https://reviews.llvm.org/D26057
llvm-svn: 297093
This is necessary in order for the evaluation of an _Atomic initializer for
those types to have an associated object, which an initializer for class or
array type needs.
llvm-svn: 295886
Removed ndrange_t as Clang builtin type and added
as a struct type in the OpenCL header.
Use type name to do the Sema checking in enqueue_kernel
and modify IR generation accordingly.
Review: D28058
Patch by Dmitry Borisenkov!
llvm-svn: 295311
Enable evaluation of captures within constexpr lambdas by using a strategy similar to that used in CodeGen:
- when starting evaluation of a lambda's call operator, create a map from VarDecl's to a closure's FieldDecls
- every time a VarDecl (or '*this) that represents a capture is encountered while evaluating the expression via the expression evaluator (specifically the LValueEvaluator) in ExprConstant.cpp - it is replaced by the corresponding FieldDecl LValue (an Lvalue-to-Rvalue conversion on this LValue representation then determines the right rvalue when needed).
Thanks to Richard Smith and Hubert Tong for their review and feedback!
https://reviews.llvm.org/D29748
llvm-svn: 295279
What we want to actually control this behavior is something more local
than an EvalutationMode. Please see the linked revision for more
discussion on why/etc.
This fixes PR31843.
Differential Revision: https://reviews.llvm.org/D29469
llvm-svn: 294800
This fixes an assertion failure that occurs later in the function when
an ObjCEncodeExpr is cast to StringLiteral.
rdar://problem/30111207
llvm-svn: 293596
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
This change adds a new type node, DeducedTemplateSpecializationType, to
represent a type template name that has been used as a type. This is modeled
around AutoType, and shares a common base class for representing a deduced
placeholder type.
We allow deduced class template types in a few more places than the standard
does: in conditions and for-range-declarators, and in new-type-ids. This is
consistent with GCC and with discussion on the core reflector. This patch
does not yet support deduced class template types being named in typename
specifiers.
llvm-svn: 293207
by providing a memchr builtin that returns char* instead of void*.
Also add a __has_feature flag to indicate the presence of constexpr forms of
the relevant <string> functions.
llvm-svn: 292555
Summary:
Per https://wg21.link/CWG1677, the C++11 standard did not clarify that constant
initialization of an object allowed constexpr brace-or-equal initialization of
subobjects:
struct foo_t { union { int i; volatile int j; } u; };
__attribute__((__require_constant_initialization__))
static const foo_t x = {{0}};
Because foo_t::u has a volatile member, the initializer for x fails. However,
there is really no good reason, because this:
union foo_u { int i; volatile int j; };
__attribute__((__require_constant_initialization__))
static const foo_u x = {0};
does have a constant initializer.
(This was triggered by musl's pthread_mutex_t type when building under C++11.)
Reviewers: rsmith
Subscribers: EricWF, cfe-commits
Differential Revision: https://reviews.llvm.org/D28427
llvm-svn: 291480
`diagnose_if` can be used to have clang emit either warnings or errors
for function calls that meet user-specified conditions. For example:
```
constexpr int foo(int a)
__attribute__((diagnose_if(a > 10, "configurations with a > 10 are "
"expensive.", "warning")));
int f1 = foo(9);
int f2 = foo(10); // warning: configuration with a > 10 are expensive.
int f3 = foo(f2);
```
It currently only emits diagnostics in cases where the condition is
guaranteed to always be true. So, the following code will emit no
warnings:
```
constexpr int bar(int a) {
foo(a);
return 0;
}
constexpr int i = bar(10);
```
We hope to support optionally emitting diagnostics for cases like that
(and emitting runtime checks) in the future.
Release notes will appear shortly. :)
Differential Revision: https://reviews.llvm.org/D27424
llvm-svn: 291418
Alex Lorenz