Don't prematurely clean up an RAII object; there's another RAII object in the
same scope that tries to save and restore the same member!
llvm-svn: 291551
Check for implicit conversion sequences for non-dependent function
template parameters between deduction and substitution. The idea is to accept
as many cases as possible, on the basis that substitution failure outside the
immediate context is much more common during substitution than during implicit
conversion sequence formation.
This re-commits r290808, reverted in r290811 and r291412, with a couple of
fixes for handling of explicitly-specified non-trailing template argument
packs.
llvm-svn: 291427
`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
Add a visitor for lambda expressions to RecordExprEvaluator in ExprConstant.cpp that creates an empty APValue of Struct type to represent the closure object. Additionally, add a LambdaExpr visitor to the TemporaryExprEvaluator that forwards constant evaluation of immediately-called-lambda-expressions to the one in RecordExprEvaluator through VisitConstructExpr.
This patch supports:
constexpr auto ID = [] (auto a) { return a; };
static_assert(ID(3.14) == 3.14);
static_assert([](auto a) { return a + 1; }(10) == 11);
Lambda captures are still not supported for constexpr lambdas.
llvm-svn: 291416
Check for implicit conversion sequences for non-dependent function
template parameters between deduction and substitution. The idea is to accept
as many cases as possible, on the basis that substitution failure outside the
immediate context is much more common during substitution than during implicit
conversion sequence formation.
This re-commits r290808, reverted in r290811, with a fix for handling of
explicitly-specified template argument packs.
llvm-svn: 291410
This patch has been sitting in review hell since july 2016 and our lack of constexpr lambda support is getting embarrassing (given that I've had a branch that implements the feature (modulo *this capture) for over a year. While in Issaquah I was enjoying shamelessly trying to convince folks of the lie that this was Richard's fault ;) I won't be able to do so in Kona since I won't be attending - so I'm going to aim to have this feature be implemented by then.
I'm quite confident of the approach in this patch, which simply maps the static-invoker 'thunk' back to the corresponding call-operator (specialization).
Thanks!
llvm-svn: 291397
This implements something like the current direction of DR1581: we use a narrow
syntactic check to determine the set of places where a constant expression
could be evaluated, and only instantiate a constexpr function or variable if
it's referenced in one of those contexts, or is odr-used.
It's not yet clear whether this is the right set of syntactic locations; we
currently consider all contexts within templates that would result in odr-uses
after instantiation, and contexts within list-initialization (narrowing
conversions take another victim...), as requiring instantiation. We could in
principle restrict the former cases more (only const integral / reference
variable initializers, and contexts in which a constant expression is required,
perhaps). However, this is sufficient to allow us to accept libstdc++ code,
which relies on GCC's behavior (which appears to be somewhat similar to this
approach).
llvm-svn: 291318
dependent context and can't be used in a constant expression.
Per C++ [temp.inst]p2, "the instantiation of a static data member does not
occur unless the static data member is used in a way that requires the
definition to exist".
This doesn't /quite/ match that, as we still instantiate static data members
that are usable in constant expressions even if the use doesn't require a
definition. A followup patch will fix that for both variables and functions.
llvm-svn: 291295
Summary:
Replace some old code that probably pre-dated the change to delay
emission of dllexported code until after the closing brace of the
outermost record type. Only uninstantiated default argument expressions
need to be handled now. It is enough to instantiate default argument
expressions when instantiating dllexported default ctors. This also
fixes some double-diagnostic issues in this area.
Fixes PR31500
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D28274
llvm-svn: 291045
Most code paths would already bail out in this case, but certain paths,
particularly overload resolution and typo correction, would not. Carrying on
with an invalid declaration could in some cases result in crashes due to
downstream code relying on declaration invariants that are not necessarily
met for invalid declarations, and in other cases just resulted in undesirable
follow-on diagnostics.
llvm-svn: 291030
Previously, if an overloaded function in a braced-init-list was encountered in
template argument deduction, and the overload set couldn't be resolved to a
particular function, we'd immediately produce a deduction failure. That's not
correct; this situation is supposed to result in that particular P/A pair being
treated as a non-deduced context, and deduction can still succeed if the type
can be deduced from elsewhere.
llvm-svn: 291014
Previously, if the arguments for a parameter pack contained a braced-init-list,
we would abort deduction (keeping the pack deductions from prior arguments) at
the point when we reached the braced-init-list, resulting in wrong deductions
and rejects-valids. We now just leave a "hole" in the pack for such an argument,
which needs to be filled by another deduction of the same pack.
llvm-svn: 290933
This reverts commit r290808, as it broken all ARM and AArch64 test-suite
test: MultiSource/UnitTests/C++11/frame_layout
Also, please, next time, try to write a commit message in according to
our guidelines:
http://llvm.org/docs/DeveloperPolicy.html#commit-messages
llvm-svn: 290811
template parameters between deduction and substitution. The idea is to accept
as many cases as possible, on the basis that substitution failure outside
the immediate context is much more common during substitution than during
implicit conversion sequence formation.
This does not implement the partial ordering portion of DR1391, which so
far appears to be misguided.
llvm-svn: 290808
We shouldn't throw a warning when the static keyword is not present in
an anonymous namespace, just like we do for -Wmissing-prototypes.
llvm-svn: 290443
Print the fully qualified names for the overload candidates. This makes
it easier to tell what the ambiguity is. Especially if a template
is instantiated after a using namespace, it will not inherit the
namespace where it was declared. The specialization will give a message
about a partial order being ambiguous for the same (unqualified) name,
which does not help identify the failure.
Addresses PR31450!
llvm-svn: 290315
This is a recommit of r290149, which was reverted in r290169 due to msan
failures. msan was failing because we were calling
`isMostDerivedAnUnsizedArray` on an invalid designator, which caused us
to read uninitialized memory. To fix this, the logic of the caller of
said function was simplified, and we now have a `!Invalid` assert in
`isMostDerivedAnUnsizedArray`, so we can catch this particular bug more
easily in the future.
Fingers crossed that this patch sticks this time. :)
Original commit message:
This patch does three things:
- Gives us the alloc_size attribute in clang, which lets us infer the
number of bytes handed back to us by malloc/realloc/calloc/any user
functions that act in a similar manner.
- Teaches our constexpr evaluator that evaluating some `const` variables
is OK sometimes. This is why we have a change in
test/SemaCXX/constant-expression-cxx11.cpp and other seemingly
unrelated tests. Richard Smith okay'ed this idea some time ago in
person.
- Uniques some Blocks in CodeGen, which was reviewed separately at
D26410. Lack of uniquing only really shows up as a problem when
combined with our new eagerness in the face of const.
llvm-svn: 290297
effect they would have in C++11. In particular, they do not prevent
value-initialization from performing zero-initialization, nor do they prevent a
struct from being an aggregate.
llvm-svn: 290229
This commit fails MSan when running test/CodeGen/object-size.c in
a confusing way. After some discussion with George, it isn't really
clear what is going on here. We can make the MSan failure go away by
testing for the invalid bit, but *why* things are invalid isn't clear.
And yet, other code in the surrounding area is doing precisely this and
testing for invalid.
George is going to take a closer look at this to better understand the
nature of the failure and recommit it, for now backing it out to clean
up MSan builds.
llvm-svn: 290169
This patch fixes an assertion that is triggered when RecordLayoutBuilder
tries to compute the size of a field (for capture "name" in the test
case) whose type hasn't been deduced. The patch fixes the bug by
correcting the typo of the capture initializer after the initializer is
parsed and before setting the expression for the annotation token.
Fixes PR30566.
rdar://problem/23380132
Differential Revision: https://reviews.llvm.org/D25206
llvm-svn: 290156
This patch does three things:
- Gives us the alloc_size attribute in clang, which lets us infer the
number of bytes handed back to us by malloc/realloc/calloc/any user
functions that act in a similar manner.
- Teaches our constexpr evaluator that evaluating some `const` variables
is OK sometimes. This is why we have a change in
test/SemaCXX/constant-expression-cxx11.cpp and other seemingly
unrelated tests. Richard Smith okay'ed this idea some time ago in
person.
- Uniques some Blocks in CodeGen, which was reviewed separately at
D26410. Lack of uniquing only really shows up as a problem when
combined with our new eagerness in the face of const.
Differential Revision: https://reviews.llvm.org/D14274
llvm-svn: 290149
* In C++, never create a FunctionNoProtoType for a builtin (fixes C++1z
crasher from r289754).
* Fix type of __sync_synchronize to be a no-parameter function rather than a
varargs function. This matches GCC.
* Fix type of vfprintf to match its actual type. We gave it a wrong type due
to PR4290 (apparently autoconf generates invalid code and expects compilers
to choke it down or it miscompiles the program; the relevant error in clang
was downgraded to a warning in r122744 to fix other occurrences of this
autoconf brokenness, so we don't need this workaround any more).
* Turn off vararg argument checking for __noop, since it's not *really* a
varargs function. Alternatively we could add custom type checking for it
and synthesize parameter types matching the actual arguments in each call,
but that seemed like overkill.
llvm-svn: 290146
lambda expression is instantiated.
Rather than waiting until Sema::CheckCXXDefaultArgExpr tries to
transform the default arguments (which fails because it can't get the
template arguments that are used), transform the default arguments
earlier when the lambda expression is transformed in
TransformLambdaExpr.
rdar://problem/27535319
Differential Revision: https://reviews.llvm.org/D23096
llvm-svn: 289990
copy constructors of classes with array members, instead using
ArrayInitLoopExpr to represent the initialization loop.
This exposed a bug in the static analyzer where it was unable to differentiate
between zero-initialized and unknown array values, which has also been fixed
here.
llvm-svn: 289618
Other compilers accept invalid code here that we reject, and we need a
better error message to try to convince users that the code is really
incorrect. Consider:
class Foo {
typedef MyIterHelper<Foo> iterator;
friend class iterator;
};
Previously our wording was "elaborated type refers to a typedef".
"elaborated type" isn't widely known terminology, so the new diagnostic
says "typedef 'iterator' cannot be referenced with class specifier".
Reviewers: rsmith
Differential Revision: https://reviews.llvm.org/D25216
llvm-svn: 289259
mirror the description in the standard. Per DR1295, this means that binding a
const / rvalue reference to a bit-field no longer "binds directly", and per
P0135R1, this means that we materialize a temporary in reference binding
after adjusting cv-qualifiers and before performing a derived-to-base cast.
In C++11 onwards, this should have fixed the last case where we would
materialize a temporary of the wrong type (with a subobject adjustment inside
the MaterializeTemporaryExpr instead of outside), but we still have to deal
with that possibility in C++98, unless we want to start using xvalues to
represent materialized temporaries there too.
llvm-svn: 289250
This saves two pointers from FunctionDecl that were being used for some
rare and questionable C-only functionality. The DeclsInPrototypeScope
ArrayRef was added in r151712 in order to parse this kind of C code:
enum e {x, y};
int f(enum {y, x} n) {
return x; // should return 1, not 0
}
The challenge is that we parse 'int f(enum {y, x} n)' it its own
function prototype scope that gets popped before we build the
FunctionDecl for 'f'. The original change was doing two questionable
things:
1. Saving all tag decls introduced in prototype scope on a TU-global
Sema variable. This is problematic when you have cases like this, where
'x' and 'y' shouldn't be visible in 'f':
void f(void (*fp)(enum { x, y } e)) { /* no x */ }
This patch fixes that, so now 'f' can't see 'x', which is consistent
with GCC.
2. Storing the decls in FunctionDecl in ActOnFunctionDeclarator so that
they could be used in ActOnStartOfFunctionDef. This is just an
inefficient way to move information around. The AST lives forever, but
the list of non-parameter decls in prototype scope is short lived.
Moving these things to the Declarator solves both of these issues.
Reviewers: rsmith
Subscribers: jmolloy, cfe-commits
Differential Revision: https://reviews.llvm.org/D27279
llvm-svn: 289225
This commit ensures that the switch warning "case value not in enumerated type"
isn't shown for opaque enums. We don't know the actual list of values in opaque
enums, so that warning is incorrect.
rdar://29230764
Differential Revision: https://reviews.llvm.org/D27299
llvm-svn: 289055
We continue to support dynamic exception specifications in C++1z as an
extension, but produce an error-by-default warning when we encounter one. This
allows users to opt back into the feature with a warning flag, and implicitly
opts system headers back into the feature should they happen to use it.
There is one semantic change implied by P0003R5 but not implemented here:
violating a throw() exception specification should now call std::terminate
directly instead of calling std::unexpected(), but since P0003R5 also removes
std::unexpected() and std::set_unexpected, and the default unexpected handler
calls std::terminate(), a conforming C++1z program cannot tell that we are
still calling it. The upside of this strategy is perfect backwards
compatibility; the downside is that we don't get the more efficient 'noexcept'
codegen for 'throw()'.
llvm-svn: 289019
When an object of class type is initialized from a prvalue of the same type
(ignoring cv qualifications), use the prvalue to initialize the object directly
instead of inserting a redundant elidable call to a copy constructor.
llvm-svn: 288866
Richard Smith