Original message:
"[modules] PR28752: Do not instantiate variable declarations which are not visible.
https://reviews.llvm.org/D24508
Patch developed in collaboration with Richard Smith!"
llvm-svn: 284008
Previously if a file-level function was defined inside befriending
template class, it always was treated as defined. For instance, the code like:
```
int func(int x);
template<typename T> class C1 {
friend int func(int x) { return x; }
};
template<typename T> class C2 {
friend int func(int x) { return x; }
};
```
could not be compiled due to function redefinition, although not of the templates
is instantiated. Moreover, the body of friend function can contain use of template
parameters, attempt to get definition of such function outside any instantiation
causes compiler abnormal termination.
Other compilers (gcc, icc) follow viewpoint that the body of the function defined
in friend declaration becomes available when corresponding class is instantiated.
This patch implements this viewpoint in clang.
Definitions introduced by friend declarations in template classes are not added
to the redeclaration chain of corresponding function. Only when the template is
instantiated, instantiation of the function definition is placed to the chain.
The fix was made in collaboration with Richard Smith.
This change fixes PR8035, PR17923, PR22307 and PR25848.
Differential Revision: http://reviews.llvm.org/D16989
llvm-svn: 283207
Summary:
Also makes -fcoroutines_ts to be both a Driver and CC1 flag.
Patch mostly by EricWF.
Reviewers: rnk, cfe-commits, rsmith, EricWF
Subscribers: mehdi_amini
Differential Revision: https://reviews.llvm.org/D25130
llvm-svn: 283064
CUDA target attributes are used for function overloading and must not be merged.
This fixes a bug where attributes were inherited during function template
specialization in CUDA and made it impossible for specialized function
to provide its own target attributes.
Differential Revision: https://reviews.llvm.org/D24522
llvm-svn: 281406
This mostly behaves cl.exe's behavior, even though clang-cl is stricter in some
corner cases and more lenient in others (see the included test).
To make the uuid declared previously here diagnostic work correctly, tweak
stripTypeAttributesOffDeclSpec() to keep attributes in the right order.
https://reviews.llvm.org/D24469
llvm-svn: 281367
Summary:
This attribute specifies expectations about the initialization of static and
thread local variables. Specifically that the variable has a
[constant initializer](http://en.cppreference.com/w/cpp/language/constant_initialization)
according to the rules of [basic.start.static]. Failure to meet this expectation
will result in an error.
Static objects with constant initializers avoid hard-to-find bugs caused by
the indeterminate order of dynamic initialization. They can also be safely
used by other static constructors across translation units.
This attribute acts as a compile time assertion that the requirements
for constant initialization have been met. Since these requirements change
between dialects and have subtle pitfalls it's important to fail fast instead
of silently falling back on dynamic initialization.
```c++
// -std=c++14
#define SAFE_STATIC __attribute__((require_constant_initialization)) static
struct T {
constexpr T(int) {}
~T();
};
SAFE_STATIC T x = {42}; // OK.
SAFE_STATIC T y = 42; // error: variable does not have a constant initializer
// copy initialization is not a constant expression on a non-literal type.
```
This attribute can only be applied to objects with static or thread-local storage
duration.
Reviewers: majnemer, rsmith, aaron.ballman
Subscribers: jroelofs, cfe-commits
Differential Revision: https://reviews.llvm.org/D23385
llvm-svn: 280525
Summary:
This attribute specifies expectations about the initialization of static and
thread local variables. Specifically that the variable has a
[constant initializer](http://en.cppreference.com/w/cpp/language/constant_initialization)
according to the rules of [basic.start.static]. Failure to meet this expectation
will result in an error.
Static objects with constant initializers avoid hard-to-find bugs caused by
the indeterminate order of dynamic initialization. They can also be safely
used by other static constructors across translation units.
This attribute acts as a compile time assertion that the requirements
for constant initialization have been met. Since these requirements change
between dialects and have subtle pitfalls it's important to fail fast instead
of silently falling back on dynamic initialization.
```c++
// -std=c++14
#define SAFE_STATIC __attribute__((require_constant_initialization)) static
struct T {
constexpr T(int) {}
~T();
};
SAFE_STATIC T x = {42}; // OK.
SAFE_STATIC T y = 42; // error: variable does not have a constant initializer
// copy initialization is not a constant expression on a non-literal type.
```
This attribute can only be applied to objects with static or thread-local storage
duration.
Reviewers: majnemer, rsmith, aaron.ballman
Subscribers: jroelofs, cfe-commits
Differential Revision: https://reviews.llvm.org/D23385
llvm-svn: 280516
textually included, create an ImportDecl just as we would if we reached a
#include of any other modular header. This is necessary in order to correctly
determine the set of variables to initialize for an imported module.
This should hopefully make the modules selfhost buildbot green again.
llvm-svn: 280409
declaration has a dependent type.
This fixes a bug where clang errors out on a valid code.
rdar://problem/28051467
Differential Revision: https://reviews.llvm.org/D24110
llvm-svn: 280330
within the instantiation of that same specialization. This could previously
happen for eagerly-instantiated function templates, variable templates,
exception specifications, default arguments, and a handful of other cases.
We still have an issue here for default template arguments that recursively
make use of themselves and likewise for substitution into the type of a
non-type template parameter, but in those cases we're producing a different
entity each time, so they should instead be caught by the instantiation depth
limit. However, currently we will typically run out of stack before we reach
it. :(
llvm-svn: 280190
to DiagnoseUninstantiableTemplate, teach hasVisibleDefinition to correctly
determine whether a function definition is visible, and mark both the function
and the template as visible when merging function template definitions to
provide hasVisibleDefinition with the relevant information.
The change to always pass the right declaration as the PatternDef to
DiagnoseUninstantiableTemplate also caused those checks to happen before other
diagnostics in InstantiateFunctionDefinition, giving worse diagnostics for the
same situations, so I sunk the relevant diagnostics into
DiagnoseUninstantiableTemplate. Those parts of this patch are based on changes
in reviews.llvm.org/D23492 by Vassil Vassilev.
This reinstates r279486, reverted in r279500, with a fix to
DiagnoseUninstantiableTemplate to only mark uninstantiable explicit
instantiation declarations as invalid if we actually diagnosed them. (When we
trigger an explicit instantiation of a class member from an explicit
instantiation declaration for the class, it's OK if there is no corresponding
definition and we certainly don't want to mark the member invalid in that
case.) This previously caused a build failure during bootstrap.
llvm-svn: 279557
to DiagnoseUninstantiableTemplate, teach hasVisibleDefinition to correctly
determine whether a function definition is visible, and mark both the function
and the template as visible when merging function template definitions to
provide hasVisibleDefinition with the relevant information.
The change to always pass the right declaration as the PatternDef to
DiagnoseUninstantiableTemplate also caused those checks to happen before other
diagnostics in InstantiateFunctionDefinition, giving worse diagnostics for the
same situations, so I sunk the relevant diagnostics into
DiagnoseUninstantiableTemplate. Those parts of this patch are based on changes
in reviews.llvm.org/D23492 by Vassil Vassilev.
llvm-svn: 279486
from p0273r0 approved by EWG). We'll eventually need to handle this from the
lexer as well, in order to disallow preprocessor directives preceding the
module declaration and to support macro import.
llvm-svn: 279196
In C, 'extern' is typically used to avoid tentative definitions when
declaring variables in headers, but adding an intializer makes it a
defintion. This is somewhat confusing, so GCC and Clang both warn on it.
In C++, 'extern' is often used to give implictly static 'const'
variables external linkage, so don't warn in that case. If selectany is
present, this might be header code intended for C and C++ inclusion, so
apply the C++ rules.
llvm-svn: 279116
This commit adds a traversal of the AST after Sema of a function that diagnoses
unguarded references to declarations that are partially available (based on
availability attributes). This traversal is only done when we would otherwise
emit -Wpartial-availability.
This commit is part of a feature I proposed here:
http://lists.llvm.org/pipermail/cfe-dev/2016-July/049851.html
Differential revision: https://reviews.llvm.org/D23003
llvm-svn: 278826
Functions of Sema that work with building of nested name specifiers have too
many parameters (BuildCXXNestedNameSpecifier already expects 10 arguments).
With this change the information about identifier and its context is packed
into a structure, which is then passes to the semantic functions.
llvm-svn: 277976
decomposition declarations.
There are a couple of things in the wording that seem strange here:
decomposition declarations are permitted at namespace scope (which we partially
support here) and they are permitted as the declaration in a template (which we
reject).
llvm-svn: 276492
we first touch any part of that module. Instead, defer them until the first
time that module is (transitively) imported. The initializer step for a module
then recursively initializes modules that its own headers imported.
For example, this avoids running the <iostream> global initializer in programs
that don't actually use iostreams, but do use other parts of the standard
library.
llvm-svn: 276159
- Changes diagnostics for Blocks to be implicitly
const qualified OpenCL v2.0 s6.12.5.
- Added and unified diagnostics of some OpenCL special types:
blocks, images, samplers, pipes. These types are intended for use
with the OpenCL builtin functions only and, therefore, most regular
uses are not allowed including assignments, arithmetic operations,
pointer dereferencing, etc.
Review: http://reviews.llvm.org/D21989
llvm-svn: 275061
- In functions with try { } catch { }, only the try block would be
skipped, not the catch blocks
- The template functions would still be parsed.
- The initializers within a constructor would still be parsed.
- The inline functions within class would still be stored, only to be
discared later.
- Invalid code with try would assert (as in "int foo() try assert_here")
This attempt to do even less while skipping function bodies.
Differential Revision: http://reviews.llvm.org/D20821
llvm-svn: 272963
The bug report by Gonzalo (https://llvm.org/bugs/show_bug.cgi?id=27507 -- which results in clang crashing when generic lambdas that capture 'this' are instantiated in contexts where the Functionscopeinfo stack is not in a reliable state - yet getCurrentThisType expects it to be) - unearthed some additional bugs in regards to maintaining proper cv qualification through 'this' when performing by value captures of '*this'.
This patch attempts to correct those bugs and makes the following changes:
o) when capturing 'this', we do not need to remember the type of 'this' within the LambdaScopeInfo's Capture - it is never really used for a this capture - so remove it.
o) teach getCurrentThisType to walk the stack of lambdas (even in scenarios where we run out of LambdaScopeInfo's such as when instantiating call operators) looking for by copy captures of '*this' and resetting the type of 'this' based on the constness of that capturing lambda's call operator.
This patch has been baking in review-hell for > 6 weeks - all the comments so far have been addressed and the bug (that it addresses in passing, and I regret not submitting as a separate patch initially) has been reported twice independently, so is frequent and important for us not to just sit on. I merged the cv qualification-fix and the PR-fix initially in one patch, since they resulted from my initial implementation of star-this and so were related. If someone really feels strongly, I can put in the time to revert this - separate the two out - and recommit. I won't claim it's immunized against all bugs, but I feel confident enough about the fix to land it for now.
llvm-svn: 272480
These ExprWithCleanups are added for holding a RunCleanupsScope not
for destructor calls; rather, they are for lifetime marks. This requires
ExprWithCleanups to keep a bit to indicate whether it have cleanups with
side effects (e.g. dtor calls).
Differential Revision: http://reviews.llvm.org/D20498
llvm-svn: 272296
Instead of setting DeclSpec's range end to point to the next token
after the DeclSpec, we use getLocForEndOfToken to insert fix-it after a type
name.
Before this fix, fix-it will change
^(NSView view) to ^(*NSView view)
This commit correctly updates the source to ^(NSView* view).
rdar://21042144
Differential Revision: http://reviews.llvm.org/D20844
llvm-svn: 271448
Wilson.
An unqualified lookup for in base classes may cause stack overflow if
the base class is a specialization of current class.
Patch by Will Wilson.
llvm-svn: 271251
If we have some function with dllimport attribute and then we have the function
definition in the same module but without dllimport attribute we should add
dllexport attribute to this function definition.
The same should be done for variables.
Example:
struct __declspec(dllimport) C3 {
~C3();
};
C3::~C3() {;} // we should export this definition.
Patch by Andrew V. Tischenko
Differential revision: http://reviews.llvm.org/D18953
llvm-svn: 270686
Summary:
In dependent contexts where we know a type name is required, such as a
new expression, we can recover by forming a DependentNameType.
This generalizes our existing compatibility hack for default arguments
for template type parameters.
Works towards parsing atlctrlw.h, which is PR26748.
Reviewers: avt77, rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D20500
llvm-svn: 270615
According to Cuda Programming guide (v7.5, E2.3.1):
> __device__, __constant__ and __shared__ variables defined in namespace
> scope, that are of class type, cannot have a non-empty constructor or a
> non-empty destructor.
Clang already deals with device-side constructors (see D15305).
This patch enforces similar rules for destructors.
Differential Revision: http://reviews.llvm.org/D20140
llvm-svn: 270108
This patch implements __unaligned (MS extension) as a proper type qualifier
(before that, it was implemented as an ignored attribute).
It also fixes PR27367 and PR27666.
Differential Revision: http://reviews.llvm.org/D20103
llvm-svn: 269220
Allow only empty constructors for local __shared__ variables in a way
identical to restrictions imposed on dynamic initializers for global
variables on device.
Differential Revision: http://reviews.llvm.org/D20039
llvm-svn: 268982
According to CUDA programming guide (v7.5):
> E.2.9.4: Within the body of a device or global function, only
> shared variables may be declared with static storage class.
Differential Revision: http://reviews.llvm.org/D20034
llvm-svn: 268962
This patch corresponds to reviews:
http://reviews.llvm.org/D15120http://reviews.llvm.org/D19125
It adds support for the __float128 keyword, literals and target feature to
enable it. Based on the latter of the two aforementioned reviews, this feature
is enabled on Linux on i386/X86 as well as SystemZ.
This is also the second attempt in commiting this feature. The first attempt
did not enable it on required platforms which caused failures when compiling
type_traits with -std=gnu++11.
If you see failures with compiling this header on your platform after this
commit, it is likely that your platform needs to have this feature enabled.
llvm-svn: 268898
When inferring availability attributes for tvos, watchos from ios, we
use the same source location and set the implicit bit to true.
So when emitting diagnostics on inferred attributes, we have a source
location.
rdar://25893544
llvm-svn: 268793
This patch implements __unaligned (MS extension) as a proper type qualifier
(before that, it was implemented as an ignored attribute).
It also fixes PR27367.
Differential Revision: http://reviews.llvm.org/D19654
llvm-svn: 268727
Usually these parameters are used solely to initialize the field in the
initializer list, and there is no real shadowing confusion.
There is a new warning under -Wshadow called
-Wshadow-field-in-constructor-modified. It attempts to find
modifications of such constructor parameters that probably intended to
modify the field.
It has some false negatives, though, so there is another warning group,
-Wshadow-field-in-constructor, which always warns on this special case.
For users who just want the old behavior and don't care about these fine
grained groups, we have a new warning group called -Wshadow-all that
activates everything.
Fixes PR16088.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D18271
llvm-svn: 267957
template<class T> void f(T) = delete;
template<> void f(int); // OK.
f(3); // OK
Implementation strategy:
When an explicit specialization of a function template, a member function template or a member function of a class template is declared, clang first implicitly instantiates the declaration of a specialization from the templated-entity being explicitly specialized (since their signatures must be the same) and then links the explicit specialization being declared as a redeclaration of the aforementioned specialization.
The problem was that when clang 'implicitly instantiates' the initial specialization, it marks the corresponding FunctionDecl as deleted if the corresponding templated-entity was deleted, rather than waiting to see whether the explicit specialization being declared provides a non-deleted body. (The eager marking of delete has advantages during overload resolution I suppose, where we don't have to try and instantiate a definition of the function to see if it is deleted).
The present fix entails recognizing that when clang knows that an explicit specialization is being declared (for whichever templated-entity), the prior implicit instantiation should not inherit the 'deleted' status, and so we reset it to false.
I suppose an alternative fix (amongst others) could consider creating a new context (ExplicitSpecializationDeclarationSubstitution or some such) that is checked during template-argument-deduction and final substitution, and avoid inheriting the deleted status during declaration substitution. But while conceptually cleaner, that would be a slightly more involved change (as could be some of the other alternatives: such as avoid tagging implicit specializations as deleted, and check their primary templates for the deleted status where needed), and so I chose a different path. Hopefully it'll prove to not be a bad choice.
llvm-svn: 266561
Since this patch provided support for the __float128 type but disabled it
on all platforms by default, some platforms can't compile type_traits with
-std=gnu++11 since there is a specialization with __float128.
This reverts the patch until D19125 is approved (i.e. we know which platforms
need this support enabled).
llvm-svn: 266460
This patch implements __unaligned as a type qualifier; before that, it was
modeled as an attribute. Proper mangling of __unaligned is implemented as well.
Some OpenCL code/tests are tangenially affected, as they relied on existing
number and sizes of type qualifiers.
Differential Revision: http://reviews.llvm.org/D18596
llvm-svn: 266415
This patch corresponds to review:
http://reviews.llvm.org/D15120
It adds support for the __float128 keyword, literals and a target feature to
enable it. This support is disabled by default on all targets and any target
that has support for this type is free to add it.
Based on feedback that I've received from target maintainers, this appears to
be the right thing for most targets. I have not heard from the maintainers of
X86 which I believe supports this type. I will subsequently investigate the
impact of enabling this on X86.
llvm-svn: 266186
This patch add support for GCC attribute((ifunc("resolver"))) for
targets that use ELF as object file format. In general ifunc is a
special kind of function alias with type @gnu_indirect_function. LLVM
patch http://reviews.llvm.org/D15525
Differential Revision: http://reviews.llvm.org/D15524
llvm-svn: 265917
Summary: A program shall not declare an explicit instantiation (14.8.2), an explicit specialization (14.8.3), or a partial specialization of a concept definition.
Reviewers: rsmith, hubert.reinterpretcast, faisalv, aaron.ballman
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D18221
llvm-svn: 265868
Add parsing, sema analysis for 'declare target' construct for OpenMP 4.0
(4.5 support will be added in separate patch).
The declare target directive specifies that variables, functions (C, C++
and Fortran), and subroutines (Fortran) are mapped to a device. The declare
target directive is a declarative directive. In Clang declare target is
implemented as implicit attribute for the declaration.
The syntax of the declare target directive is as follows:
#pragma omp declare target
declarations-definition-seq
#pragma omp end declare target
Based on patch from Michael Wong http://reviews.llvm.org/D15321
llvm-svn: 265530
With this patch, by a constexpr function is implicitly host+device
unless:
a) it's a variadic function (variadic functions are not allowed on the
device side), or
b) it's preceeded by a __device__ overload in a system header.
The restriction on overloading __host__ __device__ functions on the
basis of their CUDA attributes remains in place, but we use (b) to allow
us to define __device__ overloads for constexpr functions in cmath,
which would otherwise be __host__ __device__ and thus not overloadable.
You can disable this behavior with -fno-cuda-host-device-constexpr.
Reviewers: tra, rnk, rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D18380
llvm-svn: 264964
...as that is apparently what MSVC does. This is an updated version of r263738,
which had to be reverted in r263740 due to test failures. The original version
had erroneously emitted functions that are defined in class templates, too (see
the updated "Handle friend functions" code in EmitDeferredDecls,
lib/CodeGen/ModuleBuilder.cpp). (The updated tests needed to be split out into
their own dllexport-ms-friend.cpp because of the CHECK-NOTs which would have
interfered with subsequent CHECK-DAGs in dllexport.cpp.)
Differential Revision: http://reviews.llvm.org/D18430
llvm-svn: 264841
Summary:
* -fcuda-target-overloads
Previously unconditionally set to true by the driver. Necessary for
correct functioning of the compiler -- our CUDA headers wrapper won't
compile without this.
* -fcuda-disable-target-call-checks
Previously unconditionally set to true by the driver. Necessary to
compile almost any external CUDA code -- almost all libraries assume
that host+device code can call host or device functions.
* -fcuda-allow-host-calls-from-host-device
No effect when target overloading is enabled.
Reviewers: tra
Subscribers: rsmith, cfe-commits
Differential Revision: http://reviews.llvm.org/D18416
llvm-svn: 264739
Before this commit, we assert failure in ImplicitCastExpr
"unheralded conversion to bool". This commit fixes the assertion by using
the correct cast type when the fixed type is boolean.
This commit also fixes the behavior for Microsoft mode as well, since
Obj-C and Microsoft mode share the same code path.
rdar://24999533
llvm-svn: 264167
This commit adds a named argument to AvailabilityAttr, while r263652 adds an
optional string argument to __attribute__((deprecated)).
This was commited in r263687 and reverted in 263752 due to misaligned
access.
rdar://20588929
llvm-svn: 263958
Implement lambda capture of *this by copy.
For e.g.:
struct A {
int d = 10;
auto foo() { return [*this] (auto a) mutable { d+=a; return d; }; }
};
auto L = A{}.foo(); // A{}'s lifetime is gone.
// Below is still ok, because *this was captured by value.
assert(L(10) == 20);
assert(L(100) == 120);
If the capture was implicit, or [this] (i.e. *this was captured by reference), this code would be otherwise undefined.
Implementation Strategy:
- amend the parser to accept *this in the lambda introducer
- add a new king of capture LCK_StarThis
- teach Sema::CheckCXXThisCapture to handle by copy captures of the
enclosing object (i.e. *this)
- when CheckCXXThisCapture does capture by copy, the corresponding
initializer expression for the closure's data member
direct-initializes it thus making a copy of '*this'.
- in codegen, when assigning to CXXThisValue, if *this was captured by
copy, make sure it points to the corresponding field member, and
not, unlike when captured by reference, what the field member points
to.
- mark feature as implemented in svn
Much gratitude to Richard Smith for his carefully illuminating reviews!
llvm-svn: 263921
Summary: ...as that is apparently what MSVC does
Reviewers: rnk
Patch by Stephan Bergmann
Differential Revision: http://reviews.llvm.org/D15267
llvm-svn: 263738
This commit adds a named argument to AvailabilityAttr, while r263652 adds an
optional string argument to __attribute__((deprecated)). This enables the
compiler to provide Fix-Its for deprecated declarations.
rdar://20588929
llvm-svn: 263687
The declaration of the destructor of an invalid class was not properly marked
as noexcept. As a result, the definition of the same destructor, which was
properly implicitly marked as noexcept, would not match the definition.
This would cause the definition CXXDestructorDecl to be matked as invalid
and omited from the AST.
Differential Revision: http://reviews.llvm.org/D17988
llvm-svn: 263639
Given the following test case:
typedef struct {
const char *name;
id field;
} Test9;
extern void doSomething(Test9 arg);
void test9() {
Test9 foo2 = {0, 0};
doSomething(foo2);
}
With a release compiler, we don't emit any message and silently ignore the
variable "foo2". With an assert compiler, we get an assertion failure.
The root cause —————————————
Back in r140457 we gave InitListChecker a verification-only mode, and will use
CanUseDecl instead of DiagnoseUseOfDecl for verification-only mode.
These two functions handle unavailable issues differently:
In Sema::CanUseDecl, we say the decl is invalid when the Decl is unavailable and
the current context is available.
In Sema::DiagnoseUseOfDecl, we say the decl is usable by ignoring the return
code of DiagnoseAvailabilityOfDecl
So with an assert build, we will hit an assertion in diagnoseListInit
assert(DiagnoseInitList.HadError() &&
"Inconsistent init list check result.");
The fix -------------------
If we follow what is implemented in CanUseDecl and treat Decls with
unavailable issues as invalid, the variable decl of “foo2” will be marked as
invalid. Since unavailable checking is processed in delayed diagnostics
(r197627), we will silently ignore the diagnostics when we find out that
the variable decl is invalid.
We add a flag "TreatUnavailableAsInvalid" for the verification-only mode.
For overload resolution, we want to say decls with unavailable issues are
invalid; but for everything else, we should say they are valid and
emit diagnostics. Depending on the value of the flag, CanUseDecl
can return different values for unavailable issues.
rdar://23557300
Differential Revision: http://reviews.llvm.org/D15314
llvm-svn: 263149
Original patch by Stefan Bühler http://reviews.llvm.org/D12834
Difference between original and this one:
- fixed all comments in original code review
- added more tests, all new diagnostics now covered by tests
- moved abi_tag on re-declaration checks to Sema::mergeDeclAttributes
where they actually may work as designed
- clang-format + other stylistic changes
Mangle part will be sent for review as a separate patch.
Differential Revision: http://reviews.llvm.org/D17567
llvm-svn: 263015
- Prevent local variables to be declared in global AS
- Diagnose AS of local variables with an extern storage class
as if they would be in a program scope
Review: http://reviews.llvm.org/D17345
llvm-svn: 262641
Richard Smith