Commit Graph

4944 Commits

Author SHA1 Message Date
Clement Courbet 057f7695de [Sema] Further improvements to to static_assert diagnostics.
Summary:
We're now handling cases like `static_assert(!expr)` and
static_assert(!(expr))`.

Reviewers: aaron.ballman, Quuxplusone

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D55270

llvm-svn: 348741
2018-12-10 08:19:38 +00:00
Serge Pavlov acfcd78aec Diagnose friend function template redefinitions.
Friend function template defined in a class template becomes available if
the enclosing class template is instantiated. Until the function template
is used, it does not have a body, but still is considered a definition for
the purpose of redeclaration checks.

This change modifies redefinition check so that it can find the friend
function template definitions in instantiated classes.

Differential Revision: http://reviews.llvm.org/D21508

llvm-svn: 348473
2018-12-06 09:35:04 +00:00
Aaron Ballman c3463f6ba8 Do not check for parameters shadowing fields in function declarations.
We would issue a false-positive diagnostic for parameters in function declarations shadowing fields; we now only issue the diagnostic on a function definition instead.

llvm-svn: 348400
2018-12-05 18:56:57 +00:00
Erik Pilkington f7357c335f Address a post-commit review comment on r348325.
llvm-svn: 348388
2018-12-05 17:43:26 +00:00
Erik Pilkington 4b897a3704 [Sema] Remove some conditions of a failing assert
We should have been checking that this state is consistent, but its
possible for it to be filled later, so it isn't really sound to check
it here anyways.

Fixes llvm.org/PR39742

llvm-svn: 348325
2018-12-05 00:43:11 +00:00
Clement Courbet 9d432e0d14 [WIP][Sema] Improve static_assert diagnostics for type traits.
Summary:
In our codebase, `static_assert(std::some_type_trait<Ts...>::value, "msg")`
(where `some_type_trait` is an std type_trait and `Ts...` is the
appropriate template parameters) account for 11.2% of the `static_assert`s.

In these cases, the `Ts` are typically not spelled out explicitly, e.g.
`static_assert(std::is_same<SomeT::TypeT, typename SomeDependentT::value_type>::value, "message");`

The diagnostic when the assert fails is typically not very useful, e.g.
`static_assert failed due to requirement 'std::is_same<SomeT::TypeT, typename SomeDependentT::value_type>::value' "message"`

This change makes the diagnostic spell out the types explicitly , e.g.
`static_assert failed due to requirement 'std::is_same<int, float>::value' "message"`

See tests for more examples.

After this is submitted, I intend to handle
`static_assert(!std::some_type_trait<Ts...>::value, "msg")`,
which is another 6.6% of static_asserts.

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D54903

llvm-svn: 348239
2018-12-04 07:59:57 +00:00
Richard Smith a4ca4ca293 Fix -Wmismatched-tags to not warn on redeclarations of structs in system
headers.

Previously, we would only check whether the new declaration is in a
system header, but that requires the user to be able to correctly guess
whether a declaration in a system header is declared as a struct or a
class when specializing standard library traits templates.

We now entirely ignore declarations for which the warning was disabled
when determining whether to warn on a tag mismatch.

Also extend the diagnostic message to clarify that
 a) code containing such a tag mismatch is in fact valid and correct,
    and
 b) the (non-coding-style) reason to emit such a warning is that the
    Microsoft C++ ABI is broken and includes the tag kind in decorated
    names,
as it seems a lot of users are confused by our diagnostic here (either
not understanding why we produce it, or believing that it represents an
actual language rule).

llvm-svn: 348233
2018-12-04 02:45:28 +00:00
Fangrui Song 407659ab0a Revert "Revert r347417 "Re-Reinstate 347294 with a fix for the failures.""
It seems the two failing tests can be simply fixed after r348037

Fix 3 cases in Analysis/builtin-functions.cpp
Delete the bad CodeGen/builtin-constant-p.c for now

llvm-svn: 348053
2018-11-30 23:41:18 +00:00
Fangrui Song f5d3335d75 Revert r347417 "Re-Reinstate 347294 with a fix for the failures."
Kept the "indirect_builtin_constant_p" test case in test/SemaCXX/constant-expression-cxx1y.cpp
while we are investigating why the following snippet fails:

  extern char extern_var;
  struct { int a; } a = {__builtin_constant_p(extern_var)};

llvm-svn: 348039
2018-11-30 21:26:09 +00:00
Aaron Ballman 4b5b0c0025 Move AST tests into their own test directory; NFC.
This moves everything primarily testing the functionality of -ast-dump and -ast-print into their own directory, rather than leaving the tests spread around the testing directory.

llvm-svn: 348017
2018-11-30 18:43:02 +00:00
Fangrui Song b74d636897 Simplify the __builtin_constant_p test that was used to catch rC347417 failure
Reviewers: rsmith, void, shafik

Reviewed By: void

Subscribers: kristina, cfe-commits

Differential Revision: https://reviews.llvm.org/D54964

llvm-svn: 347895
2018-11-29 18:26:39 +00:00
Hans Wennborg 48ee4ad325 Re-commit r347417 "Re-Reinstate 347294 with a fix for the failures."
This was reverted in r347656 due to me thinking it caused a miscompile of
Chromium. Turns out it was the Chromium code that was broken.

llvm-svn: 347756
2018-11-28 14:04:12 +00:00
Zola Bridges cbac3ad122 [clang][slh] add attribute for speculative load hardening
Summary:
Resubmit this with no changes because I think the build was broken
by a different diff.
-----
The prior diff had to be reverted because there were two tests
that failed. I updated the two tests in this diff

clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/SemaCXX/attr-speculative-load-hardening.cpp

----- Summary from Previous Diff (Still Accurate) -----

LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function basis.

This can be applied to functions and Objective C methods.

Reviewers: chandlerc, echristo, kristof.beyls, aaron.ballman

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54915

llvm-svn: 347701
2018-11-27 19:56:46 +00:00
Hans Wennborg 8c79706e89 Revert r347417 "Re-Reinstate 347294 with a fix for the failures."
This caused a miscompile in Chrome (see crbug.com/908372) that's
illustrated by this small reduction:

  static bool f(int *a, int *b) {
    return !__builtin_constant_p(b - a) || (!(b - a));
  }

  int arr[] = {1,2,3};

  bool g() {
    return f(arr, arr + 3);
  }

  $ clang -O2 -S -emit-llvm a.cc -o -

g() should return true, but after r347417 it became false for some reason.

This also reverts the follow-up commits.

r347417:
> Re-Reinstate 347294 with a fix for the failures.
>
> Don't try to emit a scalar expression for a non-scalar argument to
> __builtin_constant_p().
>
> Third time's a charm!

r347446:
> The result of is.constant() is unsigned.

r347480:
> A __builtin_constant_p() returns 0 with a function type.

r347512:
> isEvaluatable() implies a constant context.
>
> Assume that we're in a constant context if we're asking if the expression can
> be compiled into a constant initializer. This fixes the issue where a
> __builtin_constant_p() in a compound literal was diagnosed as not being
> constant, even though it's always possible to convert the builtin into a
> constant.

r347531:
> A "constexpr" is evaluated in a constant context. Make sure this is reflected
> if a __builtin_constant_p() is a part of a constexpr.

llvm-svn: 347656
2018-11-27 14:01:40 +00:00
Zola Bridges 0b35afd79d Revert "[clang][slh] add attribute for speculative load hardening"
until I figure out why the build is failing or timing out

***************************

Summary:
The prior diff had to be reverted because there were two tests
that failed. I updated the two tests in this diff

clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/SemaCXX/attr-speculative-load-hardening.cpp

LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function
basis.

This can be applied to functions and Objective C methods.

Reviewers: chandlerc, echristo, kristof.beyls, aaron.ballman

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54915

This reverts commit a5b3c232d1e3613f23efbc3960f8e23ea70f2a79.
(r347617)

llvm-svn: 347628
2018-11-27 02:22:00 +00:00
Zola Bridges 3b47649fa8 [clang][slh] add attribute for speculative load hardening
Summary:
The prior diff had to be reverted because there were two tests
that failed. I updated the two tests in this diff

clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/SemaCXX/attr-speculative-load-hardening.cpp

----- Summary from Previous Diff (Still Accurate) -----

LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function basis.

This can be applied to functions and Objective C methods.

Reviewers: chandlerc, echristo, kristof.beyls, aaron.ballman

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54915

llvm-svn: 347617
2018-11-27 00:03:44 +00:00
Zola Bridges e8e8c5cf4d Revert "[clang][slh] add attribute for speculative load hardening"
This reverts commit 801eaf91221ba6dd6996b29ff82659ad6359e885.

llvm-svn: 347588
2018-11-26 20:11:18 +00:00
Zola Bridges b0fd2db8fc [clang][slh] add attribute for speculative load hardening
Summary:
LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function basis.

This can be applied to functions and Objective C methods.

Reviewers: chandlerc, echristo

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54555

llvm-svn: 347586
2018-11-26 19:41:14 +00:00
Sylvestre Ledru 72c5fcf088 Create a diagnostic group for warn_call_to_pure_virtual_member_function_from_ctor_dtor, so it can be turned into an error using Werror
Summary: Patch by Arnaud Bienner

Reviewers: davide, rsmith, jkorous

Reviewed By: jkorous

Subscribers: jkorous, sylvestre.ledru, cfe-commits

Differential Revision: https://reviews.llvm.org/D53807

llvm-svn: 347555
2018-11-26 14:29:48 +00:00
Bill Wendling 372b1e796b A "constexpr" is evaluated in a constant context. Make sure this is reflected
if a __builtin_constant_p() is a part of a constexpr.

llvm-svn: 347531
2018-11-26 02:10:53 +00:00
Bill Wendling 1af8dd6a1e isEvaluatable() implies a constant context.
Assume that we're in a constant context if we're asking if the expression can
be compiled into a constant initializer. This fixes the issue where a
__builtin_constant_p() in a compound literal was diagnosed as not being
constant, even though it's always possible to convert the builtin into a
constant.

llvm-svn: 347512
2018-11-24 10:45:55 +00:00
Bill Wendling 6ff1751f7d Re-Reinstate 347294 with a fix for the failures.
Don't try to emit a scalar expression for a non-scalar argument to
__builtin_constant_p().

Third time's a charm!

llvm-svn: 347417
2018-11-21 20:44:18 +00:00
Jorge Gorbe Moya 59974412a4 Mark lambda decl as invalid if a captured variable has an invalid type.
This causes the compiler to crash when trying to compute a layout for
the lambda closure type (see included test).

llvm-svn: 347402
2018-11-21 17:49:37 +00:00
Nico Weber 9f0246d473 Revert r347364 again, the fix was incomplete.
llvm-svn: 347389
2018-11-21 12:47:43 +00:00
Bill Wendling 91549ed15f Reinstate 347294 with a fix for the failures.
EvaluateAsInt() is sometimes called in a constant context. When that's the
case, we need to specify it as so.

llvm-svn: 347364
2018-11-20 23:24:16 +00:00
Nico Weber 6438972553 Revert 347294, it turned many bots on lab.llvm.org:8011/console red.
llvm-svn: 347314
2018-11-20 15:27:43 +00:00
Bill Wendling 107b0e9881 Use is.constant intrinsic for __builtin_constant_p
Summary:
A __builtin_constant_p may end up with a constant after inlining. Use
the is.constant intrinsic if it's a variable that's in a context where
it may resolve to a constant, e.g., an argument to a function after
inlining.

Reviewers: rsmith, shafik

Subscribers: jfb, kristina, cfe-commits, nickdesaulniers, jyknight

Differential Revision: https://reviews.llvm.org/D54355

llvm-svn: 347294
2018-11-20 08:53:30 +00:00
Vedant Kumar c9a9531a03 [Sema] Fix PR38987: keep end location of a direct initializer list
If PerformConstructorInitialization of a direct initializer list constructor is
called while instantiating a template, it has brace locations in its BraceLoc
arguments but not in the Kind argument.

This reverts the hunk https://reviews.llvm.org/D41921#inline-468844.

Patch by Orivej Desh!

Differential Revision: https://reviews.llvm.org/D53231

llvm-svn: 347261
2018-11-19 20:10:21 +00:00
Zi Xuan Wu 64d85a29ed [Clang][Sema]Choose a better candidate in overload function call if there is a compatible vector conversion instead of ambiguous call error
There are 2 function variations with vector type parameter. When we call them with argument of different vector type we would prefer to 
choose the variation with implicit argument conversion of compatible vector type instead of incompatible vector type. For example,

typedef float __v4sf __attribute__((__vector_size__(16)));
void f(vector float);
void f(vector signed int);

int main {
   __v4sf a;
   f(a);
}

Here, we'd like to choose f(vector float) but not report an ambiguous call error.

Differential revision: https://reviews.llvm.org/D53417

llvm-svn: 347019
2018-11-16 03:00:00 +00:00
Richard Smith 28ddb91dec [c++20] Implement P0482R6: enable -fchar8_t by default in C++20 mode.
This unfortunately results in a substantial breaking change when
switching to C++20, but it's not yet clear what / how much we should
do about that. We may want to add a compatibility conversion from
u8 string literals to const char*, similar to how C++98 provided a
compatibility conversion from string literals to non-const char*,
but that's not handled by this patch.

The feature can be disabled in C++20 mode with -fno-char8_t.

llvm-svn: 346892
2018-11-14 21:04:34 +00:00
Erik Pilkington ba88e21f8c [Sema] Make sure we substitute an instantiation-dependent default template argument
Fixes llvm.org/PR39623

Differential revision: https://reviews.llvm.org/D54414

llvm-svn: 346709
2018-11-12 21:31:06 +00:00
Richard Smith bd844e0de7 PR39628 Treat all non-zero values as 'true' in bool compound-assignment
in constant evaluation, not just odd values.

llvm-svn: 346699
2018-11-12 20:11:57 +00:00
Aaron Ballman ac77dcd764 Allow a double-underscore spelling of Clang attributes using double square bracket syntax.
This matches a similar behavior with GCC accepting [[gnu::__attr__]] as a alias for [[gnu::attr]] in that clang attributes can now be spelled with two leading and trailing underscores.

I had always intended for this to work, but missed the critical bit. We already had an existing test in test/Preprocessor/has_attribute.cpp for [[clang::__fallthrough__]] but using that spelling would still give an "unknown attribute" diagnostic.

llvm-svn: 346547
2018-11-09 19:37:18 +00:00
Aaron Ballman c44c174246 Introduce the _Clang scoped attribute token.
Currently, we only accept clang as the scoped attribute identifier for double square bracket attributes provided by Clang, but this has the potential to conflict with user-defined macros. To help alleviate these concerns, this introduces the _Clang scoped attribute identifier as an alias for clang. It also introduces a warning with a fixit on the off chance someone attempts to use __clang__ as the scoped attribute (which is a predefined compiler identification macro).

llvm-svn: 346521
2018-11-09 17:19:45 +00:00
Bill Wendling 8003edc9aa Compound literals, enums, et al require const expr
Summary:
Compound literals,  enums, file-scoped arrays, etc. require their
initializers and size specifiers to be constant. Wrap the initializer
expressions in a ConstantExpr so that we can easily check for this later
on.

Reviewers: rsmith, shafik

Reviewed By: rsmith

Subscribers: cfe-commits, jyknight, nickdesaulniers

Differential Revision: https://reviews.llvm.org/D53921

llvm-svn: 346455
2018-11-09 00:41:36 +00:00
Matt Davis c50240dac1 [AST] Get aliased type info from an aliased TemplateSpecialization.
Summary:
Previously the TemplateSpecialization instance for 'template_alias', in the example below, returned the type info of the  canonical type (int).  This ignored the type alias if the template type happen to be aliased. 

Before this patch, the assert would trigger with an  alignment of 4:
```
typedef int __attribute__(( aligned( 16 ) )) aligned_int;
template < typename >
using template_alias = aligned_int;
static_assert( alignof( template_alias<void>) == 16, "" );
```

This patch checks if the TemplateSpecialization type has an alias, and if so will return the type information for the aliased type, else the canonical type's info is returned (original behavior).  I believe that this is the desired behavior.  

Reviewers: aaron.ballman, rjmccall

Reviewed By: rjmccall

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D54048

llvm-svn: 346146
2018-11-05 17:25:26 +00:00
Brian Gesiak a87ecf6c7f [coroutines] Fix fallthrough warning on try/catch
Summary:
The test case added in this diff would incorrectly warn that control
flow may fall through without returning. Here's a standalone example:
https://godbolt.org/z/dCwXEi

The same program, but using `return` instead of `co_return`, does not
produce a warning: https://godbolt.org/z/mVldqQ

The issue was in how Clang analysis would structure its representation
of the control-flow graph. Specifically, when constructing the CFG,
`CFGBuilder::Visit` had special handling of a `ReturnStmt`, in which it
would place object destructors in the same CFG block as a `return` statement,
immediately after it. Doing so would allow the logic in
`lib/Sema/AnalysisBasedWarning.cpp` `CheckFallThrough` to work properly in the
program that used `return`, correctly determining that no "plain edges" preceded
the exit block of the function.

Because a `co_return` statement would not enjoy the same treatment when
it was being built into the control-flow graph, object destructors
would not be placed in the same CFG block as the `co_return`, thus
resulting in a "plain edge" preceding the exit block of the function,
and so the warning logic would be triggered.

Add special casing for `co_return` to Clang analysis, thereby
remedying the mistaken warning.

Test Plan: `check-clang`

Reviewers: GorNishanov, tks2103, rsmith

Reviewed By: GorNishanov

Subscribers: EricWF, lewissbaker, cfe-commits

Differential Revision: https://reviews.llvm.org/D54075

llvm-svn: 346074
2018-11-03 22:35:17 +00:00
Aaron Ballman b55cd69a67 Diagnose parameter names that shadow the names of inherited fields under -Wshadow-field.
This addresses PR34120. Note, unlike GCC, we take into account the accessibility of the field when deciding whether to warn or not.

llvm-svn: 346041
2018-11-02 21:04:44 +00:00
Richard Smith df4994cc5a Fix test expectation to match reality.
llvm-svn: 345423
2018-10-26 19:42:43 +00:00
Richard Smith 6822bd79ac PR26547: alignof should return ABI alignment, not preferred alignment
Summary:
- Add `UETT_PreferredAlignOf` to account for the difference between `__alignof` and `alignof`
- `AlignOfType` now returns ABI alignment instead of preferred alignment iff clang-abi-compat > 7, and one uses _Alignof or alignof

Patch by Nicole Mazzuca!

Differential Revision: https://reviews.llvm.org/D53207

llvm-svn: 345419
2018-10-26 19:26:45 +00:00
Nicolas Lesser 3cde5e4a4c [C++17] Reject shadowing of capture by parameter in lambda
Summary:
This change rejects the shadowing of a capture by a parameter in lambdas in C++17.

```
int main() {
  int a;
  auto f = [a](int a) { return a; };
}
```

results in:

```
main.cpp:3:20: error: a lambda parameter cannot shadow an explicitly captured entity
  auto f = [a](int a) { return a; };
                   ^
main.cpp:3:13: note: variable a is explicitly captured here
  auto f = [a](int a) { return a; };
            ^
```

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: lebedev.ri, erik.pilkington, cfe-commits

Differential Revision: https://reviews.llvm.org/D53595

llvm-svn: 345308
2018-10-25 20:15:03 +00:00
Eric Fiselier 3b4bbe7b0f Revert "[SemaCXX] Unconfuse Clang when std::align_val_t is unscoped in C++03"
This reverts commit b5d8d0de744d2c212bdb17d5c5fd4447dd14dbd2.

llvm-svn: 345306
2018-10-25 19:50:43 +00:00
Eric Fiselier 84eaf0c9e4 [SemaCXX] Unconfuse Clang when std::align_val_t is unscoped in C++03
Summary:
When -faligned-allocation is specified in C++03 libc++ defines std::align_val_t as an unscoped enumeration type (because Clang didn't provide scoped enumerations as an extension until 8.0).
Unfortunately Clang confuses the `align_val_t` overloads of delete with the sized deallocation overloads which aren't enabled. This caused Clang to call the aligned deallocation function as if it were the sized deallocation overload.

For example: https://godbolt.org/z/xXJELh

This patch fixes the confusion.

Reviewers: rsmith, EricWF

Reviewed By: EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D53508

llvm-svn: 345296
2018-10-25 18:16:16 +00:00
Will Wilson caa02f879f [ms] Prevent explicit constructor name lookup if scope is missing
MicrosoftExt allows explicit constructor calls. Prevent lookup of constructor name unless the name has explicit scope.
This avoids a compile-time crash due to confusing a member access for a constructor name.

Test case included. All tests pass.

Differential Revision: https://reviews.llvm.org/D53441

llvm-svn: 345258
2018-10-25 11:45:32 +00:00
Richard Trieu f371380fc9 [Sema] Fix -Wcomma for C89
There is a small difference in the scope flags for C89 versus the other C/C++
dialects.  This change ensures that the -Wcomma warning won't be duplicated or
issued in the wrong location.  Also, the test case is refactored into C and C++
parts, with the C++ parts guarded by a #ifdef to allow the test to run in both
modes.

https://bugs.llvm.org/show_bug.cgi?id=32370

llvm-svn: 345228
2018-10-25 01:08:00 +00:00
Eric Fiselier 1265ddef99 Revert "[SemaCXX] Unconfuse Clang when std::align_val_t is unscoped in C++03"
This reverts commit 6f47cdd51341344c0e32630e19e72c94cd25f34e.

llvm-svn: 345225
2018-10-24 23:47:04 +00:00
Eric Fiselier 5e707cb274 [SemaCXX] Unconfuse Clang when std::align_val_t is unscoped in C++03
Summary:
When -faligned-allocation is specified in C++03 libc++ defines std::align_val_t as an unscoped enumeration type (because Clang didn't provide scoped enumerations as an extension until 8.0).
Unfortunately Clang confuses the `align_val_t` overloads of delete with the sized deallocation overloads which aren't enabled. This caused Clang to call the aligned deallocation function as if it were the sized deallocation overload.

For example: https://godbolt.org/z/xXJELh

This patch fixes the confusion.

Reviewers: rsmith, EricWF

Reviewed By: EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D53508

llvm-svn: 345211
2018-10-24 22:38:49 +00:00
Aaron Ballman ad672ffb64 Support accepting __gnu__ as a scoped attribute namespace that aliases to gnu.
This is useful in libstdc++ to avoid clashes with identifiers in the user's namespace.

llvm-svn: 345132
2018-10-24 12:26:23 +00:00
Richard Trieu a451599f89 [Sema] Fix -Wcomma in dependent context
When there is a dependent type inside a cast, the CastKind becomes CK_Dependent
instead of CK_ToVoid.  This fix will check that there is a dependent cast,
the original type is dependent, and the target type is void to ignore the cast.

https://bugs.llvm.org/show_bug.cgi?id=39375

llvm-svn: 345111
2018-10-24 02:07:41 +00:00
Aaron Ballman a529bc3d26 Silence the -Wshadow warning for enumerators shadowing a type.
Amends r344259 so that enumerators shadowing types are not diagnosed, as shadowing under those circumstances is rarely (if ever) an issue in practice.

llvm-svn: 344898
2018-10-22 13:05:53 +00:00
Richard Trieu 6b13e89ab8 Make -Wfor-loop-analysis work with C++17
For now, disable the "variable in loop condition not modified" warning to not
be emitted when there is a structured binding variable in the loop condition.

https://bugs.llvm.org/show_bug.cgi?id=39285

llvm-svn: 344828
2018-10-20 02:15:58 +00:00
Richard Smith b3d203ff7f PR24164, PR39336: init-captures are not distinct full-expressions.
Rather, they are subexpressions of the enclosing lambda-expression, and
any temporaries in them are destroyed at the end of that
full-expression, or when the corresponding lambda-expression is
destroyed if they are lifetime-extended.

llvm-svn: 344801
2018-10-19 19:01:34 +00:00
David Bolvansky d46b05df84 [Test] Fix test file for C++98 mode
llvm-svn: 344762
2018-10-18 21:26:01 +00:00
David Bolvansky 1b2a9a3b53 [Diagnostics] Add missing expected warning to test file
llvm-svn: 344761
2018-10-18 21:06:14 +00:00
Aaron Ballman 20ea72476c Improve -Wshadow warnings with enumerators.
Addresses PR24718 by checking for enumerators that shadow other enumerators. Catches issues like:

enum E1{e1};
void f(void) {
  enum E2{e1};
}

llvm-svn: 344259
2018-10-11 16:40:18 +00:00
Louis Dionne 8c98eebea1 [clang] Fix failing attribute test on Windows
The test added in r344146 was failing because the ABI on Windows is
different, and that test includes ABI-specific details. The test now
harcodes which ABI to use so we can rely on those details.

llvm-svn: 344159
2018-10-10 17:37:37 +00:00
Erik Pilkington d1a184fc6a [Sema] Fix a multiple definition bug with friends and templates
The problem was that MergeFunctionDecl sometimes needs the injected template
arguments of a FunctionTemplateDecl, but is called before adding the new
template to the redecl chain. This leads to multiple common pointers in the same
redecl chain, each with their own identical instantiation. Fix this by merging
the the common state before inserting the new template into the redecl chain.

rdar://44810129

Differential revision: https://reviews.llvm.org/D53046

llvm-svn: 344157
2018-10-10 17:17:51 +00:00
Louis Dionne e6e817534a [clang] Properly apply attributes on explicit instantiations of static data members
Summary: https://llvm.org/PR39118

Reviewers: aaron.ballman, rnk

Subscribers: dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D52675

llvm-svn: 344146
2018-10-10 15:32:29 +00:00
Brian Gesiak 0b56830011 [coro]Pass rvalue reference for named local variable to return_value
Summary:
Addressing https://bugs.llvm.org/show_bug.cgi?id=37265.

Implements [class.copy]/33 of coroutines TS.

When the criteria for elision of a copy/move operation are met, but not
for an exception-declaration, and the object to be copied is designated by an
lvalue, or when the expression in a return or co_return statement is a
(possibly parenthesized) id-expression that names an object with automatic
storage duration declared in the body or parameter-declaration-clause of the
innermost enclosing function or lambda-expression, overload resolution to select
the constructor for the copy or the return_value overload to call is first
performed as if the object were designated by an rvalue.

Patch by Tanoy Sinha!

Reviewers: modocache, GorNishanov

Reviewed By: modocache, GorNishanov

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D51741

llvm-svn: 343949
2018-10-08 03:08:39 +00:00
Aaron Puchert b0a2a0cf7d Thread safety analysis: Handle conditional expression in getTrylockCallExpr
Summary:
We unwrap conditional expressions containing try-lock functions.

Additionally we don't acquire on conditional expression branches, since
that is usually not helpful. When joining the branches we would almost
certainly get a warning then.

Hopefully fixes an issue that was raised in D52398.

Reviewers: aaron.ballman, delesley, hokein

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D52888

llvm-svn: 343902
2018-10-06 01:09:28 +00:00
James Y Knight c7d3e609fb Emit diagnostic note when calling an invalid function declaration.
The comment said it was intentionally not emitting any diagnostic
because the declaration itself was already diagnosed. However,
everywhere else that wants to not emit a diagnostic without an extra
note emits note_invalid_subexpr_in_const_expr instead, which gets
suppressed later.

This was the only place which did not emit a diagnostic note.

Differential Revision: https://reviews.llvm.org/D52919

llvm-svn: 343867
2018-10-05 17:49:48 +00:00
Aaron Puchert 35389e51f3 Thread safety analysis: Examine constructor arguments
Summary:
Instead of only examining call arguments, we also examine constructor
arguments applying the same rules.

That was an opportunity for refactoring the examination procedure to
work with iterators instead of integer indices. For the case of
CallExprs no functional change is intended.

Reviewers: aaron.ballman, delesley

Reviewed By: delesley

Subscribers: JonasToth, cfe-commits

Differential Revision: https://reviews.llvm.org/D52443

llvm-svn: 343831
2018-10-04 23:51:14 +00:00
Louis Dionne d269579a97 [clang] Add the exclude_from_explicit_instantiation attribute
Summary:
This attribute allows excluding a member of a class template from being part
of an explicit template instantiation of that class template. This also makes
sure that code using such a member will not take for granted that an external
instantiation exists in another translation unit. The attribute was discussed
on cfe-dev at [1] and is primarily motivated by the removal of always_inline
in libc++ to control what's part of the ABI (see links in [1]).

[1]: http://lists.llvm.org/pipermail/cfe-dev/2018-August/059024.html

rdar://problem/43428125

Reviewers: rsmith

Subscribers: dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D51789

llvm-svn: 343790
2018-10-04 15:49:42 +00:00
Petr Pavlu ed083f2c1f [constexpr] Fix ICE when memcpy() is given a pointer to an incomplete array
Fix code for constant evaluation of __builtin_memcpy() and
__builtin_memmove() that would attempt to divide by zero when given two
pointers to an incomplete array.

Differential Revision: https://reviews.llvm.org/D51855

llvm-svn: 343761
2018-10-04 09:25:44 +00:00
Aaron Puchert 7146b0032f Thread safety analysis: Unwrap __builtin_expect in getTrylockCallExpr
Summary:
When people are really sure they'll get the lock they sometimes use
__builtin_expect. It's also used by some assertion implementations.
Asserting that try-lock succeeded is basically the same as asserting
that the lock is not held by anyone else (and acquiring it).

Reviewers: aaron.ballman, delesley

Reviewed By: aaron.ballman

Subscribers: kristina, cfe-commits

Differential Revision: https://reviews.llvm.org/D52398

llvm-svn: 343681
2018-10-03 11:58:19 +00:00
Richard Smith 8baa50013c [cxx2a] P0614R1: Support init-statements in range-based for loops.
We don't yet support this for the case where a range-based for loop is
implicitly rewritten to an ObjC for..in statement.

llvm-svn: 343350
2018-09-28 18:44:09 +00:00
Richard Smith cff420120f Handle dependent class template names in class template argument
deduction for new-expressions.

llvm-svn: 343293
2018-09-28 03:18:53 +00:00
Richard Smith 9b2c5e7c44 [cxx2a] P0641R2: (Some) type mismatches on defaulted functions only
render the function deleted instead of rendering the program ill-formed.

This change also adds an enabled-by-default warning for the case where
an explicitly-defaulted special member function of a non-template class
is implicitly deleted by the type checking rules. (This fires either due
to this language change or due to pre-C++20 reasons for the member being
implicitly deleted). I've tested this on a large codebase and found only
bugs (where the program means something that's clearly different from
what the programmer intended), so this is enabled by default, but we
should revisit this if there are problems with this being enabled by
default.

llvm-svn: 343285
2018-09-28 01:16:43 +00:00
Richard Smith 864949bda1 [cxx2a] P0624R2: Lambdas with no capture-default are
default-constructible and assignable.

llvm-svn: 343279
2018-09-27 22:47:04 +00:00
Martin Storsjo 0b339e4d80 [Sema] Handle __va_start for Windows/ARM64 in the same way as for ARM
This fixes PR39090.

Differential Revision: https://reviews.llvm.org/D52571

llvm-svn: 343184
2018-09-27 08:24:15 +00:00
Richard Smith 79c88c3105 P1008R1 Classes with user-declared constructors are never aggregates in
C++20.

llvm-svn: 343131
2018-09-26 19:00:16 +00:00
Richard Smith 236ffdeeb2 P0962R1: only use the member form of 'begin' and 'end' in a range-based
for loop if both members exist.

This resolves a DR whereby an errant 'begin' or 'end' member in a base
class could result in a derived class not being usable as a range with
non-member 'begin' and 'end'.

llvm-svn: 342925
2018-09-24 23:17:44 +00:00
Richard Trieu 8d3fa39a0d Update smart pointer detection for thread safety analysis.
Objects are determined to be smart pointers if they have both a star and arrow
operator.  Some implementations of smart pointers have these overloaded
operators in a base class, while the check only searched the derived class.
This fix will also look for the operators in the base class.

llvm-svn: 342794
2018-09-22 01:50:52 +00:00
Erik Pilkington f452337787 [Sema] Retain __restrict qualifiers when substituting a reference type.
Fixes rdar://43760099

Differential revision: https://reviews.llvm.org/D52271

llvm-svn: 342672
2018-09-20 18:12:24 +00:00
Aaron Puchert 7ba1ab71ec Thread Safety Analysis: warnings for attributes without arguments
Summary:
When thread safety annotations are used without capability arguments,
they are assumed to apply to `this` instead. So we warn when either
`this` doesn't exist, or the class is not a capability type.

This is based on earlier work by Josh Gao that was committed in r310403,
but reverted in r310698 because it didn't properly work in template
classes. See also D36237.

The solution is not to go via the QualType of `this`, which is then a
template type, hence the attributes are not known because it could be
specialized. Instead we look directly at the class in which we are
contained.

Additionally I grouped two of the warnings together. There are two
issues here: the existence of `this`, which requires us to be a
non-static member function, and the appropriate annotation on the class
we are contained in. So we don't distinguish between not being in a
class and being static, because in both cases we don't have `this`.

Fixes PR38399.

Reviewers: aaron.ballman, delesley, jmgao, rtrieu

Reviewed By: delesley

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D51901

llvm-svn: 342605
2018-09-20 00:39:27 +00:00
Aaron Puchert f6ccde7810 Thread safety analysis: Fix crash for function pointers
For function pointers, the FunctionDecl of the callee is unknown, so
getDirectCallee will return nullptr. We have to catch that case to avoid
crashing. We assume there is no attribute then.

llvm-svn: 342519
2018-09-19 00:19:38 +00:00
Aaron Puchert e33105e8c2 Thread safety analysis: Run more tests with capability attributes [NFC]
Summary:
We run the tests for -Wthread-safety-{negative,verbose} with the new
attributes as well as the old ones. Also put the macros in a header so
that we don't have to copy them all around.

The warn-thread-safety-parsing.cpp test checks for warnings depending on
the actual attribute name, so it can't undergo the same treatment.

Together with D49275 this should fix PR33754.

Reviewers: aaron.ballman, delesley, grooverdan

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D52141

llvm-svn: 342418
2018-09-17 21:37:22 +00:00
Louis Dionne 3c011e1e3c [clang] Make sure attributes on member classes are applied properly
Summary:
Attributes on member classes of class templates and member class templates
of class templates are not currently instantiated. This was discovered by
Richard Smith here:

  http://lists.llvm.org/pipermail/cfe-dev/2018-September/059291.html

This commit makes sure that attributes are instantiated properly. This
commit does not fix the broken behavior for member partial and explicit
specializations of class templates.

PR38913

Reviewers: rsmith

Subscribers: dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D51997

llvm-svn: 342238
2018-09-14 14:07:16 +00:00
Vedant Kumar 35d303adbf [Sema] Remove location from implicit capture init expr
A lambda's closure is initialized when the lambda is declared. For
implicit captures, the initialization code emitted from EmitLambdaExpr
references source locations *within the lambda body* in the function
containing the lambda. This results in a poor debugging experience: we
step to the line containing the lambda, then into lambda, out again,
over and over, until every capture's field is initialized.

To improve stepping behavior, assign the starting location of the lambda
to expressions which initialize an implicit capture within it.

rdar://39807527

Differential Revision: https://reviews.llvm.org/D50927

llvm-svn: 342194
2018-09-13 23:28:25 +00:00
Richard Smith 128719c4fe Fix crash on call to __builtin_memcpy with a null pointer to an
incomplete type.

Also improve the diagnostics for similar situations.

llvm-svn: 342192
2018-09-13 22:47:33 +00:00
Erik Pilkington c587164422 [AST] Fix a crash on invalid.
Problem was that we were appending to the source location info buffer in the
copy assignment operator (instead of overwriting).

rdar://42746401

llvm-svn: 341869
2018-09-10 21:54:04 +00:00
Richard Smith 8eeb16f5d1 Enhance -Wc++14-compat for class template argument deduction to list the
deduced type (if known).

llvm-svn: 341858
2018-09-10 20:31:03 +00:00
Erich Keane 659c871a1b Prevent cpu-specific/cpu-dispatch from giong on a lambda.
It is non-sensical to use cpu-specific/cpu-dispatch multiversioning
on a lambda, so prevent it when trying to add the attribute.

llvm-svn: 341833
2018-09-10 14:31:56 +00:00
Richard Smith 4576a77b80 PR33222: Require the declared return type not the actual return type to
match when checking for redeclaration of a function template.

This properly handles differences in deduced return types, particularly
when performing redeclaration checks for a friend function template.

llvm-svn: 341778
2018-09-10 06:35:32 +00:00
Richard Smith 4ced5d751b Part of PR33222: defer enforcing return type mismatch for dependent
friend function declarations of class templates.

llvm-svn: 341775
2018-09-10 05:32:13 +00:00
Akira Hatanaka 2ccb31977c [Sema] Check that the destructor for each element of class type is
accessible from the context where aggregate initialization occurs.

rdar://problem/38168772

Differential Revision: https://reviews.llvm.org/D45898

llvm-svn: 341629
2018-09-07 02:38:01 +00:00
Richard Smith 5159bbad8b PR38627: Fix handling of exception specification adjustment for
destructors.

We previously tried to patch up the exception specification after
completing the class, which went wrong when the exception specification
was needed within the class body (in particular, by a friend
redeclaration of the destructor in a nested class). We now mark the
destructor as having a not-yet-computed exception specification
immediately after creating it.

This requires delaying various checks against the exception
specification (where we'd previously have just got the wrong exception
specification, and now find we have an exception specification that we
can't compute yet) when those checks fire while the class is being
defined.

This also exposed an issue that we were missing a CodeSynthesisContext
for computation of exception specifications (otherwise we'd fail to make
the module containing the definition of the class visible when computing
its members' exception specs). Adding that incidentally also gives us a
diagnostic quality improvement.

This has also exposed an pre-existing problem: making the exception
specification evaluation context a non-SFINAE context (as it should be)
results in a bootstrap failure; PR38850 filed for this.

llvm-svn: 341499
2018-09-05 22:30:37 +00:00
Richard Smith 59ef620059 Add test file missed from r341097.
llvm-svn: 341099
2018-08-30 19:17:11 +00:00
Richard Smith 218538ebe9 Add missing -Wc++11-compat / -Wc++14-compat warnings for:
* generic lambdas
 * return type deduction
 * class template argument deduction

llvm-svn: 341098
2018-08-30 19:16:35 +00:00
Aaron Ballman 57deab77de Thread safety analysis no longer hands when analyzing a self-referencing initializer.
This fixes PR38640.

llvm-svn: 340636
2018-08-24 18:48:35 +00:00
Aaron Puchert c3e37b7538 Thread safety analysis: Allow relockable scopes
Summary:
It's already allowed to prematurely release a scoped lock, now we also
allow relocking it again, possibly even in another mode.

This is the second attempt, the first had been merged as r339456 and
reverted in r339558 because it caused a crash.

Reviewers: delesley, aaron.ballman

Reviewed By: delesley, aaron.ballman

Subscribers: hokein, cfe-commits

Differential Revision: https://reviews.llvm.org/D49885

llvm-svn: 340459
2018-08-22 22:14:53 +00:00
Erik Pilkington 63e7ab18e5 Address Aaron Ballman's post-commit review comments from r340306, NFC
llvm-svn: 340311
2018-08-21 17:50:10 +00:00
Erik Pilkington 5a559e64a9 Add a new flag and attributes to control static destructor registration
This commit adds the flag -fno-c++-static-destructors and the attributes
[[clang::no_destroy]] and [[clang::always_destroy]]. no_destroy specifies that a
specific static or thread duration variable shouldn't have it's destructor
registered, and is the default in -fno-c++-static-destructors mode.
always_destroy is the opposite, and is the default in -fc++-static-destructors
mode.

A variable whose destructor is disabled (either because of
-fno-c++-static-destructors or [[clang::no_destroy]]) doesn't count as a use of
the destructor, so we don't do any access checking or mark it referenced. We
also don't emit -Wexit-time-destructors for these variables.

rdar://21734598

Differential revision: https://reviews.llvm.org/D50994

llvm-svn: 340306
2018-08-21 17:24:06 +00:00
Richard Smith e43e2b3667 Model type attributes as regular Attrs.
Specifically, AttributedType now tracks a regular attr::Kind rather than
having its own parallel Kind enumeration, and AttributedTypeLoc now
holds an Attr* instead of holding an ad-hoc collection of Attr fields.

Differential Revision: https://reviews.llvm.org/D50526

This reinstates r339623, reverted in r339638, with a fix to not fail
template instantiation if we instantiate a QualType with no associated
type source information and we encounter an AttributedType.

llvm-svn: 340215
2018-08-20 21:47:29 +00:00
Nick Desaulniers 1aaf524ea1 [SEMA] add more -Wfloat-conversion to compound assigment analysis
Summary: Fixes Bug: https://bugs.llvm.org/show_bug.cgi?id=27061

Reviewers: aaron.ballman, acoomans

Reviewed By: aaron.ballman, acoomans

Subscribers: acoomans, cfe-commits, srhines, pirama

Differential Revision: https://reviews.llvm.org/D50467

llvm-svn: 339581
2018-08-13 16:38:07 +00:00
Martin Bohme 4e1293b5e1 Summary:Add clang::reinitializes attribute
Summary:
This is for use by clang-tidy's bugprone-use-after-move check -- see
corresponding clang-tidy patch at https://reviews.llvm.org/D49910.

Reviewers: aaron.ballman, rsmith

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D49911

llvm-svn: 339569
2018-08-13 14:11:03 +00:00
Haojian Wu 74e0f40d98 Revert "Allow relockable scopes with thread safety attributes."
This reverts commit r339456.

The change introduces a new crash, see

class SCOPED_LOCKABLE FileLock {
 public:
  explicit FileLock()
      EXCLUSIVE_LOCK_FUNCTION(file_);
  ~FileLock() UNLOCK_FUNCTION(file_);
  void Lock() EXCLUSIVE_LOCK_FUNCTION(file_);
  Mutex file_;
};

void relockShared2() {
  FileLock file_lock;
  file_lock.Lock();
}

llvm-svn: 339558
2018-08-13 12:50:30 +00:00
Aaron Ballman a97e4dc899 Allow relockable scopes with thread safety attributes.
Patch by Aaron Puchert

llvm-svn: 339456
2018-08-10 17:33:47 +00:00
Richard Smith 2e34bbd8e8 PR38286: Don't crash when attempting to define a constructor for an
incomplete class template.

llvm-svn: 339210
2018-08-08 00:42:42 +00:00
Richard Smith 06f71b5bd8 [constexpr] Support for constant evaluation of __builtin_memcpy and
__builtin_memmove (in non-type-punning cases).

This is intended to permit libc++ to make std::copy etc constexpr
without sacrificing the optimization that uses memcpy on
trivially-copyable types.

__builtin_strcpy and __builtin_wcscpy are not handled by this change.
They'd be straightforward to add, but we haven't encountered a need for
them just yet.

This reinstates r338455, reverted in r338602, with a fix to avoid trying
to constant-evaluate a memcpy call if either pointer operand has an
invalid designator.

llvm-svn: 338941
2018-08-04 00:57:17 +00:00
Aaron Ballman eaa18e60eb Properly add shared locks to the initial list of locks being tracked, instead of assuming unlock functions always use exclusive locks.
Patch by Aaron Puchert.

llvm-svn: 338912
2018-08-03 19:37:45 +00:00
Michael Kruse dc5ce72afa Append new attributes to the end of an AttributeList.
Recommit of r335084 after revert in r335516.

... instead of prepending it at the beginning (the original behavior
since implemented in r122535 2010-12-23). This builds up an
AttributeList in the the order in which the attributes appear in the
source.

The reverse order caused nodes for attributes in the AST (e.g. LoopHint)
to be in the reverse order, and therefore printed in the wrong order in
-ast-dump. Some TODO comments mention this. The order was explicitly
reversed for enable_if attribute overload resolution and name mangling,
which is not necessary anymore with this patch.

The change unfortunately has some secondary effect, especially on
diagnostic output. In the simplest cases, the CHECK lines or expected
diagnostic were changed to the the new output. If the kind of
error/warning changed, the attributes' order was changed instead.

This unfortunately causes some 'previous occurrence here' hints to be
textually after the main marker. This typically happens when attributes
are merged, but are incompatible to each other. Interchanging the role
of the the main and note SourceLocation will also cause the case where
two different declaration's attributes (in contrast to multiple
attributes of the same declaration) are merged to be reverse. There is
no easy fix because sometimes previous attributes are merged into a new
declaration's attribute list, sometimes new attributes are added to a
previous declaration's attribute list. Since 'previous occurrence here'
pointing to locations after the main marker is not rare, I left the
markers as-is; it is only relevant when the attributes are declared in
the same declaration anyway.

Differential Revision: https://reviews.llvm.org/D48100

llvm-svn: 338800
2018-08-03 01:21:16 +00:00
Hans Wennborg 6bd4f924e7 Revert r338455 "[constexpr] Support for constant evaluation of __builtin_memcpy and __builtin_memmove (in non-type-punning cases)."
It caused asserts during Chromium builds, see reply on the cfe-commits thread.

> This is intended to permit libc++ to make std::copy etc constexpr
> without sacrificing the optimization that uses memcpy on
> trivially-copyable types.
>
> __builtin_strcpy and __builtin_wcscpy are not handled by this change.
> They'd be straightforward to add, but we haven't encountered a need for
> them just yet.

llvm-svn: 338602
2018-08-01 17:51:23 +00:00
Richard Smith ad5bbcceb7 Avoid exposing name for range-based for '__range' variables in lifetime warnings.
llvm-svn: 338467
2018-08-01 01:03:33 +00:00
Richard Smith f4e248c23e [P0936R0] add [[clang::lifetimebound]] attribute
This patch adds support for a new attribute, [[clang::lifetimebound]], that
indicates that the lifetime of a function result is related to one of the
function arguments. When walking an initializer to make sure that the lifetime
of the initial value is at least as long as the lifetime of the initialized
object, we step through parameters (including the implicit object parameter of
a non-static member function) that are marked with this attribute.

There's nowhere to write an attribute on the implicit object parameter, so in
lieu of that, it may be applied to a function type (where it appears
immediately after the cv-qualifiers and ref-qualifier, which is as close to a
declaration of the implicit object parameter as we have). I'm currently
modeling this in the AST as the attribute appertaining to the function type.

Differential Revision: https://reviews.llvm.org/D49922

llvm-svn: 338464
2018-08-01 00:33:25 +00:00
Richard Smith 96beffba15 [constexpr] Support for constant evaluation of __builtin_memcpy and
__builtin_memmove (in non-type-punning cases).

This is intended to permit libc++ to make std::copy etc constexpr
without sacrificing the optimization that uses memcpy on
trivially-copyable types.

__builtin_strcpy and __builtin_wcscpy are not handled by this change.
They'd be straightforward to add, but we haven't encountered a need for
them just yet.

llvm-svn: 338455
2018-07-31 23:35:09 +00:00
Richard Smith 5f2a349280 PR38355 Prevent infinite recursion when checking initializer lifetime if
an initializer is self-referential.

llvm-svn: 338230
2018-07-30 07:19:54 +00:00
Erik Pilkington 69770d3d7a [Sema] Use a TreeTransform to extract deduction guide parameter types
Previously, we just canonicalized the type, but this lead to crashes with
parameter types that referred to ParmVarDecls of the constructor. There may be
more cases that this TreeTransform needs to handle though, such as a constructor
parameter type referring to a member in an unevaluated context. Canonicalization
doesn't address these cases either though, so we can address them as-needed in
follow-up commits.

rdar://41330135

Differential revision: https://reviews.llvm.org/D49439

llvm-svn: 338165
2018-07-27 21:23:48 +00:00
Erik Pilkington dd0b344339 [Sema] Fix a crash by completing a type before using it
Only apply this exception on a type that we're able to check.

rdar://41903969

Differential revision: https://reviews.llvm.org/D49868

llvm-svn: 338089
2018-07-26 23:40:42 +00:00
Richard Smith ef6c43dc0c Refactor checking of switch conditions and case values.
Check each case value in turn while parsing it, performing the
conversion to the switch type within the context of the expression
itself. This will become necessary in order to properly handle cleanups
for temporaries created as part of the case label (in an upcoming
patch). For now it's just good hygiene.

This necessitates moving the checking for the switch condition itself to
earlier, so that the destination type is available when checking the
case labels.

As a nice side-effect, we get slightly improved diagnostic quality and
error recovery by separating the case expression checking from the case
statement checking and from tracking whether there are discarded case
labels.

llvm-svn: 338056
2018-07-26 18:41:30 +00:00
Aaron Ballman 1b58759d82 Allow thread safety annotation lock upgrading and downgrading.
Patch thanks to Aaron Puchert!

llvm-svn: 338024
2018-07-26 13:03:16 +00:00
Richard Smith a3fd116219 Don't lifetime-extend or track lifetime problems through the LHS of '->*'.
Fixes a false-positive warning found by selfhost.

llvm-svn: 337857
2018-07-24 21:18:30 +00:00
Roman Lebedev d55661db3c [Sema] Mark implicitly-inserted ICE's as being part of explicit cast (PR38166)
Summary:
As discussed in [[ https://bugs.llvm.org/show_bug.cgi?id=38166 | PR38166 ]], we need to be able to distinqush whether the cast
we are visiting is actually a cast, or part of an `ExplicitCast`.
There are at least four ways to get there:
1. Introduce a new `CastKind`, and use it instead of `IntegralCast` if we are in `ExplicitCast`.

   Would work, but does not scale - what if we will need more of these cast kinds?
2. Introduce a flag in `CastExprBits`, whether this cast is part of `ExplicitCast` or not.

   Would work, but it isn't immediately clear where it needs to be set.
2. Fix `ScalarExprEmitter::VisitCastExpr()` to visit these `NoOp` casts.

   As pointed out by @rsmith, CodeGenFunction::EmitMaterializeTemporaryExpr calls

   skipRValueSubobjectAdjustments, which steps over the CK_NoOp cast`,

   which explains why we currently don't visit those.

   This is probably impossible, as @efriedma points out, that is intentional as per `[class.temporary]` in the standard
3. And the simplest one, just record which NoOp casts we skip.

   It just kinda works as-is afterwards.

But, the approach with a flag is the least intrusive one, and is probably the best one overall.

Reviewers: rsmith, rjmccall, majnemer, efriedma

Reviewed By: rsmith

Subscribers: cfe-commits, aaron.ballman, vsk, llvm-commits, rsmith

Differential Revision: https://reviews.llvm.org/D49508

llvm-svn: 337815
2018-07-24 08:16:50 +00:00
Richard Smith 3e6101b4b7 Add missing testcase update for r337790.
llvm-svn: 337792
2018-07-24 01:23:36 +00:00
Richard Smith 0e3102d1dc Warn if a local variable's initializer retains a pointer/reference to a
non-lifetime-extended temporary object.

llvm-svn: 337790
2018-07-24 00:55:08 +00:00
Richard Smith f66e4f7dbd Support lifetime-extension of conditional temporaries.
llvm-svn: 337767
2018-07-23 22:56:45 +00:00
Erik Pilkington a3a462e5ca [Sema] Fix crash on BlockExprs in a default member initializers
Clang would crash when instantiating a BlockDecl that appeared in a
default-member-initializer of a class template. Fix this by deferring the
instantiation until we instantate the BlockExpr.

rdar://41200624

Differential revision: https://reviews.llvm.org/D49688

llvm-svn: 337766
2018-07-23 22:47:37 +00:00
Richard Smith 6a32c0589c Do not try to perform lifetime-extension through conditional
expressions.

CodeGen can't cope with that yet. Instead, produce a "not supported"
warning for now and don't extend lifetime.

llvm-svn: 337744
2018-07-23 21:21:24 +00:00
Richard Smith afe48f9d68 Fold -Wreturn-stack-address into general initialization lifetime
checking.

llvm-svn: 337743
2018-07-23 21:21:22 +00:00
Erich Keane c764e9a87e Update to -r337585, allow scoped enum inits in -pedantic
llvm-svn: 337738
2018-07-23 21:08:13 +00:00
Richard Smith ca975b2f58 Fold dangling-field warning into general initialization lifetime checks.
This reinstates r337627, reverted in r337671, with a fix to correctly
handle the lvalueness of array subscript expressions on pointers.

llvm-svn: 337726
2018-07-23 18:50:26 +00:00
Erich Keane 1ddd4bf87f Prevent Scoped Enums from being Integral constant expressions:
Discovered because of: https://bugs.llvm.org/show_bug.cgi?id=38235

It seems to me that a scoped enum should NOT be an integral constant expression
without a cast, so this seems like a sensical change.

Attributes that check for an integer parameter simply use this function to
ensure that they have an integer, so it was previously allowing a scoped enum.

Also added a test based on Richard's feedback to ensure that case labels still work.

Differential Revision: https://reviews.llvm.org/D49599

llvm-svn: 337585
2018-07-20 17:42:09 +00:00
Erich Keane 3efe00206f Implement cpu_dispatch/cpu_specific Multiversioning
As documented here: https://software.intel.com/en-us/node/682969 and
https://software.intel.com/en-us/node/523346. cpu_dispatch multiversioning
is an ICC feature that provides for function multiversioning.

This feature is implemented with two attributes: First, cpu_specific,
which specifies the individual function versions. Second, cpu_dispatch,
which specifies the location of the resolver function and the list of
resolvable functions.

This is valuable since it provides a mechanism where the resolver's TU
can be specified in one location, and the individual implementions
each in their own translation units.

The goal of this patch is to be source-compatible with ICC, so this
implementation diverges from the ICC implementation in a few ways:
1- Linux x86/64 only: This implementation uses ifuncs in order to
properly dispatch functions. This is is a valuable performance benefit
over the ICC implementation. A future patch will be provided to enable
this feature on Windows, but it will obviously more closely fit ICC's
implementation.
2- CPU Identification functions: ICC uses a set of custom functions to identify
the feature list of the host processor. This patch uses the cpu_supports
functionality in order to better align with 'target' multiversioning.
1- cpu_dispatch function def/decl: ICC's cpu_dispatch requires that the function
marked cpu_dispatch be an empty definition. This patch supports that as well,
however declarations are also permitted, since the linker will solve the
issue of multiple emissions.

Differential Revision: https://reviews.llvm.org/D47474

llvm-svn: 337552
2018-07-20 14:13:28 +00:00
Erich Keane a67eb91047 Enable C++2a Chrono Literals
C++2a via http://wg21.link/p0355 permits the library
literals of 'd' and 'y'. This patch enables them in the
Lexer so that they can be properly parsed.

Note that 'd' gets confused with the hex character, so
modifications to how octal, binary, and decimal numbers are
parsed were required. Since this is simply making previously
invalid code legal, this should be fine.

Hex still greedily parses the 'd' as a hexit, since it would
a: violate [lex.ext]p1
b: break existing code.

Differential Revision: https://reviews.llvm.org/D49504

llvm-svn: 337454
2018-07-19 13:36:57 +00:00
Erich Keane 7963e8bebb Add support for __declspec(code_seg("segname"))
This patch uses CodeSegAttr to represent __declspec(code_seg) rather than 
building on the existing support for #pragma code_seg.
The code_seg declspec is applied on functions and classes. This attribute 
enables the placement of code into separate named segments, including compiler-
generated codes and template instantiations.

For more information, please see the following:
https://msdn.microsoft.com/en-us/library/dn636922.aspx

This patch fixes the regression for the support for attribute ((section).
746b78de78

Patch by Soumi Manna (Manna)
Differential Revision: https://reviews.llvm.org/D48841

llvm-svn: 337420
2018-07-18 20:04:48 +00:00
Richard Smith d87aab939a Restructure checking for, and warning on, lifetime extension.
This change implements C++ DR1696, which makes initialization of a
reference member of a class from a temporary object ill-formed. The
standard wording here is imprecise, but we interpret it as meaning that
any time a mem-initializer would result in lifetime extension, the
program is ill-formed.

This reinstates r337226, reverted in r337255, with a fix for the
InitializedEntity alignment problem that was breaking ARM buildbots.

llvm-svn: 337329
2018-07-17 22:24:09 +00:00
Benjamin Kramer c41e096bda Revert "[Sema] Reword warning for constant captures that are not required"
This reverts commit r337152. This applies to non-constants too. The real
explanation is that the capture is not ODR-used, but putting that into
the warning message seems ... worse.

llvm-svn: 337278
2018-07-17 13:17:01 +00:00
Florian Hahn 0aa117dd2c Temporarily revert r337226 "Restructure checking for, and warning on, lifetime extension."
This change breaks on ARM because pointers to clang::InitializedEntity are only
4 byte aligned and do not have 3 bits to store values. A possible solution
would be to change the fields in clang::InitializedEntity to enforce a bigger
alignment requirement.

The error message is

llvm/include/llvm/ADT/PointerIntPair.h:132:3: error: static_assert failed "PointerIntPair with integer size too large for pointer"
  static_assert(IntBits <= PtrTraits::NumLowBitsAvailable,
include/llvm/ADT/PointerIntPair.h:73:13: note: in instantiation of template class 'llvm::PointerIntPairInfo<const clang::InitializedEntity *, 3, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *> >' requested here
    Value = Info::updateInt(Info::updatePointer(0, PtrVal),
llvm/include/llvm/ADT/PointerIntPair.h:51:5: note: in instantiation of member function 'llvm::PointerIntPair<const clang::InitializedEntity *, 3, (anonymous namespace)::LifetimeKind, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *>, llvm::PointerIntPairInfo<const clang::InitializedEntity *, 3, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *> > >::setPointerAndInt' requested here
    setPointerAndInt(PtrVal, IntVal);
    ^
llvm/tools/clang/lib/Sema/SemaInit.cpp:6237:12: note: in instantiation of member function 'llvm::PointerIntPair<const clang::InitializedEntity *, 3, (anonymous namespace)::LifetimeKind, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *>, llvm::PointerIntPairInfo<const clang::InitializedEntity *, 3, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *> > >::PointerIntPair' requested here
    return {Entity, LK_Extended};

Full log here:
http://lab.llvm.org:8011/builders/clang-cmake-armv7-global-isel/builds/1330
http://lab.llvm.org:8011/builders/clang-cmake-armv7-full/builds/1394

llvm-svn: 337255
2018-07-17 09:23:31 +00:00
Richard Smith 0a9969b36b Restructure checking for, and warning on, lifetime extension.
This change implements C++ DR1696, which makes initialization of a
reference member of a class from a temporary object ill-formed. The
standard wording here is imprecise, but we interpret it as meaning that
any time a mem-initializer would result in lifetime extension, the
program is ill-formed.

llvm-svn: 337226
2018-07-17 00:11:41 +00:00
Benjamin Kramer c8c90e5b40 [Sema] Reword warning for constant captures that are not required
This is one of the darker corners of C++, make it clear that this is
about constants and rephrase it a bit.

Before: lambda capture 'i' is not required to be captured for this use
After:  lambda capture of constant 'i' is not required for this use
llvm-svn: 337152
2018-07-16 09:52:02 +00:00
Aaron Ballman f279169d9e Run thread safety tests with both lock and capability attributes; NFC to the analysis behavior.
Patch thanks to Aaron Puchert.

llvm-svn: 337125
2018-07-15 12:08:52 +00:00
Erich Keane f702b029f4 PR15730/PR16986 Allow dependently typed vector_size types.
As listed in the above PRs, vector_size doesn't allow
dependent types/values. This patch introduces a new
DependentVectorType to handle a VectorType that has a dependent
size or type.

In the future, ALL the vector-types should be able to create one
of these to handle dependent types/sizes as well. For example,
DependentSizedExtVectorType could likely be switched to just use
this instead, though that is left as an exercise for the future.


Differential Revision: https://reviews.llvm.org/D49045

llvm-svn: 337036
2018-07-13 19:46:04 +00:00
Nicolas Lesser 1ad0e9f039 Fix PR34668 - P0704R1 implementation is too permissive
Summary:
https://bugs.llvm.org/show_bug.cgi?id=34668

Pretty straightforward.

Reviewers: rsmith, Rakete1111

Reviewed By: Rakete1111

Subscribers: Rakete1111, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D38075

llvm-svn: 337017
2018-07-13 16:27:45 +00:00
Richard Smith b64764a30b PR38141: check whether noexcept-specifications are equivalent in redeclarations
llvm-svn: 336946
2018-07-12 21:11:25 +00:00
Nicolas Lesser 8217a2ab4f [C++11] Fix warning when dropping cv-qualifiers when assigning to a reference with a braced initializer list
llvm-svn: 336922
2018-07-12 17:43:49 +00:00
Joel E. Denny 72c2783012 [FileCheck] Add -allow-deprecated-dag-overlap to failing clang tests
See https://reviews.llvm.org/D47106 for details.

Reviewed By: probinson

Differential Revision: https://reviews.llvm.org/D47172

llvm-svn: 336844
2018-07-11 20:26:20 +00:00
Brian Gesiak c1c681c948 [SemaCXX] Remove comment from coroutines test, NFC
Summary:
The file name was accidentally included when the test file was added.

Test Plan: check-clang

llvm-svn: 336750
2018-07-11 01:00:53 +00:00
Brian Gesiak 32ee712435 Remove qualtype qualifier in coroutine error to prevent assert in debug
Summary:
A forward-declared coroutine_traits should trip an error; we need
a complete type.

Unfortunately, in debug mode only, we trip an assert when attempting
to provide the fully qualified type for the error message.
If you try to compile a program with a forward-declared
coroutine_traits in debug mode, clang will crash.

I've included a test for the behavior and removed the q modifier
on the error message. This prevents the crash in debug mode and
does not change the behavior for the error message on a
forward-declaration of a coroutine_traits type.

Test Plan:
I've included a test for the forward-declaration.

Patch by Tanoy Sinha!

Reviewers: modocache, GorNishanov

Reviewed By: modocache

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D49099

llvm-svn: 336748
2018-07-11 00:45:48 +00:00
Richard Smith a3405ffcec DR330: look through array types when forming the cv-decomposition of a type.
This allows more qualification conversions, eg. conversion from
   'int *(*)[]' -> 'const int *const (*)[]'
is now permitted, along with all the consequences of that: more types
are similar, more cases are permitted by const_cast, and conversely,
fewer "casting away constness" cases are permitted by reinterpret_cast.

llvm-svn: 336745
2018-07-11 00:19:19 +00:00
Erich Keane 9960b8f13a Revert -r336726, which included more files than intended.
llvm-svn: 336727
2018-07-10 20:51:41 +00:00
Erich Keane 7b8c12e7cc [NFC] Switch CodeGenFunction to use value init instead of member init lists
The member init list for the sole constructor for CodeGenFunction
has gotten out of hand, so this patch moves the non-parameter-dependent
initializations into the member value inits.

llvm-svn: 336726
2018-07-10 20:46:46 +00:00
Erik Pilkington 1c5ae9bc1f [Sema] Fix a structured binding typo correction bug
BindingDecls have null type until their initializer is processed, so we can't
assume that a correction candidate has non-null type.

rdar://41559582

llvm-svn: 336634
2018-07-10 02:15:07 +00:00
Richard Smith d82201e7c6 P0806R2 Implicit capture of this with a capture-default of [=] is
deprecated.

Add a -Wdeprecated warning for this in C++2a onwards. (In C++17 and
before, there isn't a reasonable alternative because [=,this] is
ill-formed.)

llvm-svn: 336480
2018-07-07 05:58:48 +00:00
Richard Trieu 0282655f9d Check returned type is valid before using it.
Add a .isNull() check to returned QualType.  Fixes PR38077

llvm-svn: 336475
2018-07-07 00:17:25 +00:00
Ilya Biryukov a2d582563d [Sema] Fix crash in getConstructorName.
Summary:
Can happen when getConstructorName is called on invalid decls,
specifically the ones that do not have the injected class name.

Reviewers: bkramer, rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D48880

llvm-svn: 336244
2018-07-04 08:50:12 +00:00
Erik Pilkington f5d83f3768 [Sema] Discarded statment should be an evaluatable context.
The constexpr evaluator was erroring out because these templates weren't
defined. Despite being used in a discarded statement, we still need to constexpr
evaluate them, which means that we need to instantiate them. Fixes PR37585.

Differential revision: https://reviews.llvm.org/D48322

llvm-svn: 336233
2018-07-03 22:15:36 +00:00
Nico Weber f08125c7c4 Add regression test for PR37935.
llvm-svn: 335725
2018-06-27 12:05:06 +00:00
Michael Kruse 41dd6ced2c Revert "Append new attributes to the end of an AttributeList."
This reverts commit r335084 as requested by David Jones and
Eric Christopher because of differences of emitted warnings.

llvm-svn: 335516
2018-06-25 20:06:13 +00:00
Brian Gesiak c1b173a636 [Sema] isValidCoroutineContext FIXME and citations
Summary:
Add citations to the Coroutines TS to the `isValidCoroutineContext`
function, as well as a FIXME and test for [expr.await]p2, which states
a co_await expression cannot be used in a default argument.

Test Plan: check-clang

Reviewers: GorNishanov, EricWF

Reviewed By: GorNishanov

Subscribers: rsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D48519

llvm-svn: 335420
2018-06-23 18:01:02 +00:00
Anastasia Stulova bf549bf402 [Sema] Updated note for address spaces to print the type.
This allows to reuse the same diagnostic for OpenCL or CUDA.

llvm-svn: 335358
2018-06-22 15:45:08 +00:00
Chandler Carruth 16e6bc23a1 [x86] Teach the builtin argument range check to allow invalid ranges in
dead code.

This is important for C++ templates that essentially compute the valid
input in a way that is constant and will cause all the invalid cases to
be dead code that is deleted. Code in the wild actually does this and
GCC also accepts these kinds of patterns so it is important to support
it.

To make this work, we provide a non-error path to diagnose these issues,
and use a default-error warning instead. This keeps the relatively
strict handling but prevents nastiness like SFINAE on these errors. It
also allows us to safely use the system to diagnose this only when it
occurs at runtime (in emitted code).

Entertainingly, this required fixing the syntax in various other ways
for the x86 test because we never bothered to diagnose that the returns
were invalid.

Since debugging these compile failures was super confusing, I've also
improved the diagnostic to actually say what the value was. Most of the
checks I've made ignore this to simplify maintenance, but I've checked
it in a few places to make sure the diagnsotic is working.

Depends on D48462. Without that, we might actually crash some part of
the compiler after bypassing the error here.

Thanks to Richard, Ben Kramer, and especially Craig Topper for all the
help here.

Differential Revision: https://reviews.llvm.org/D48464

llvm-svn: 335309
2018-06-21 23:46:09 +00:00
Michael Kruse ea31f0e4b8 Append new attributes to the end of an AttributeList.
... instead of prepending it at the beginning (the original behavior
since implemented in r122535 2010-12-23). This builds up an
AttributeList in the the order in which the attributes appear in the
source.

The reverse order caused nodes for attributes in the AST (e.g. LoopHint)
to be in the reverse, and therefore printed in the wrong order by
-ast-dump. Some TODO comments mention this. The order was explicitly
reversed for enable_if attribute overload resolution and name mangling,
which is not necessary anymore with this patch.

The change unfortunately has some secondary effects, especially for
diagnostic output. In the simplest cases, the CHECK lines or expected
diagnostic were changed to the the new output. If the kind of
error/warning changed, the attribute's order was changed instead.

It also causes some 'previous occurrence here' hints to be textually
after the main marker. This typically happens when attributes are
merged, but are incompatible. Interchanging the role of the the main
and note SourceLocation will also cause the case where two different
declaration's attributes (in contrast to multiple attributes of the
same declaration) are merged to be reversed. There is no easy fix
because sometimes previous attributes are merged into a new
declaration's attribute list, sometimes new attributes are added to a
previous declaration's attribute list. Since 'previous occurrence here'
pointing to locations after the main marker is not rare, I left the
markers as-is; it is only relevant when the attributes are declared in
the same declaration anyway, which often is on the same line.

Differential Revision: https://reviews.llvm.org/D48100

llvm-svn: 335084
2018-06-19 23:46:52 +00:00
Nico Weber 3d7f00d25b clang-cl: Emit narrowing diag for initializer lists if -fmsc-version is at least 1900 (i.e. MSVC2015).
Diagnostics for narrowing conversions in initializer lists are currently
DefaultIgnored in Microsoft mode. But MSVC 2015 did add warnings about
narrowing conversions (C2397), so clang-cl can remove its special case code if
MSCompatibilityVersion is new enough.

(In MSVC, C2397 is just a warning and in clang it's default-mapped to an error,
but it can be remapped, and disabled with -Wno-c++11-narrowing, so that should
be fine.)

Fixes PR37314.
https://reviews.llvm.org/D48296

llvm-svn: 335082
2018-06-19 23:19:34 +00:00
Taiju Tsuiki 3be68e162f Revert r335019 "Update NRVO logic to support early return (Attempt 2)"
llvm-svn: 335022
2018-06-19 05:35:30 +00:00
Taiju Tsuiki b000a8860e Update NRVO logic to support early return (Attempt 2)
Summary:
This is the second attempt of r333500 (Update NRVO logic to support early return).
The previous one was reverted for a miscompilation for an incorrect NRVO set up on templates such as:
```
struct Foo {};

template <typename T>
T bar() {
  T t;
  if (false)
    return T();
  return t;
}
```

Where, `t` is marked as non-NRVO variable before its instantiation. However, while its instantiation, it's left an NRVO candidate, turned into an NRVO variable later.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D47586

llvm-svn: 335019
2018-06-19 04:39:07 +00:00
Erich Keane 436e5cc0f1 Simplify test from r334650
No reason to have the 'bool' as an intermediary value,
simply use the fact that curley braces enforce eval order.

llvm-svn: 334652
2018-06-13 20:47:12 +00:00
Erich Keane 00958270aa Implement constexpr __builtin_*_overflow
As requested here:https://bugs.llvm.org/show_bug.cgi?id=37633
permit the __builtin_*_overflow builtins in constexpr functions.

Differential Revision: https://reviews.llvm.org/D48040

llvm-svn: 334650
2018-06-13 20:43:27 +00:00
Erich Keane 1d73d1aaa1 Correct behavior of __builtin_*_overflow and constexpr.
Enable these builtins to be called across a lambda
boundary with captureless const/constexpr, as brought up by 
Eli here: https://reviews.llvm.org/D48040

Differential Revision: https://reviews.llvm.org/D48053

llvm-svn: 334597
2018-06-13 13:25:11 +00:00
Akira Hatanaka 4ac16db5d2 [Sema] When the address of a member function is used as a template
argument, use the context in which it is used for checking its
accessibility.

This fixes PR32898.

rdar://problem/33737747

Differential Revision: https://reviews.llvm.org/D36918

llvm-svn: 334569
2018-06-13 05:26:23 +00:00
Erich Keane 2fcbe9283f Fix overload resolution between Ptr-To-Member and Bool
As reported here (https://bugs.llvm.org/show_bug.cgi?id=19808)
and discovered independently when looking at plum-hall tests,
we incorrectly implemented over.ics.rank, which says "A conversion
that is not a conversion of a pointer, or pointer to member, to bool
is better than another conversion that is such a conversion.".

In the current Draft (N4750), this is phrased slightly differently in
paragraph 4.1: A conversion that does not convert a pointer, a pointer
to member, or std::nullptr_t to bool is better than one that does.

The comment on isPointerConversionToBool (the changed function)
also confirms that this is the case (note outdated reference):
isPointerConversionToBool - Determines whether this conversion is
a conversion of a pointer or pointer-to-member to bool. This is
used as part of the ranking of standard conversion sequences
(C++ 13.3.3.2p4).

However, despite this comment, it didn't check isMemberPointerType
on the 'FromType', presumably incorrectly assuming that 'isPointerType' 
matched it.  This patch fixes this by adding isMemberPointerType to
this function. Additionally, member function pointers are just 
MemberPointerTypes that point to functions insted of data, so that
is fixed in this patch as well.

llvm-svn: 334503
2018-06-12 13:59:32 +00:00
Sunil Srivastava a74031b640 Change the wording of RTTI errors to make them more generic.
An attempt to use dynamic_cast while rtti is disabled, used to emit the error:

  cannot use dynamic_cast with -fno-rtti

and a similar one for typeid.

This patch changes that to:

  use of dynamic_cast requires -frtti

Differential Revision: https://reviews.llvm.org/D47291

llvm-svn: 334153
2018-06-07 00:42:59 +00:00
Ilya Biryukov 26a35dae83 Change test to output 'pcm' to the temp dir, not the source dir
llvm-svn: 334073
2018-06-06 08:50:12 +00:00
Jan Korous 67da1257ee [Sema] Fix parsing of anonymous union in language linkage specification
C++17 [dcl.link]p4:
A linkage specification does not establish a scope.

C++17 [class.union.anon]p2:
Namespace level anonymous unions shall be declared static.

Differential Revision: https://reviews.llvm.org/D45884

rdar://problem/37545925

llvm-svn: 334062
2018-06-06 05:16:34 +00:00
Richard Smith e4899c1648 PR37631: verify that a member deduction guide has the same access as its template.
llvm-svn: 333599
2018-05-30 22:13:43 +00:00
Richard Smith 2600c63d96 PR34520: after instantiating a non-templated member deduction guide, don't forget to push it into the class scope.
llvm-svn: 333589
2018-05-30 20:24:10 +00:00
Joel E. Denny 857613bc6d [AST] Fix loss of enum forward decl from decl context
For example, given:

  enum __attribute__((deprecated)) T *p;

-ast-print produced:

  enum T *p;

The attribute was lost because the enum forward decl was lost.

Another example is the loss of enum forward decls from C++ namespaces
(in MS compatibility mode).

The trouble was that the EnumDecl node was suppressed, as revealed by
-ast-dump.  The suppression of the EnumDecl was intentional in
r116122, but I don't understand why.  The suppression isn't needed for
the test suite to behave.

Reviewed by: rsmith

Differential Revision: https://reviews.llvm.org/D46846

llvm-svn: 333574
2018-05-30 18:33:53 +00:00
Sam McCall 5429bd751c Revert "Update NRVO logic to support early return"
This reverts commit r333500, which causes stage2 compiler crashes.

llvm-svn: 333547
2018-05-30 14:14:58 +00:00
Taiju Tsuiki 44f9c585b9 Update NRVO logic to support early return
Summary:
The previous implementation misses an opportunity to apply NRVO (Named Return Value
Optimization) below. That discourages user to write early return code.

```
struct Foo {};

Foo f(bool b) {
  if (b)
    return Foo();
  Foo oo;
  return oo;
}
```
That is, we can/should apply RVO for a local variable if:
 * It's directly returned by at least one return statement.
 * And, all reachable return statements in its scope returns the variable directly.
While, the previous implementation disables the RVO in a scope if there are multiple return
statements that refers different variables.

On the new algorithm, local variables are in NRVO_Candidate state at first, and a return
statement changes it to NRVO_Disabled for all visible variables but the return statement refers.
Then, at the end of the function AST traversal, NRVO is enabled for variables in NRVO_Candidate
state and refers from at least one return statement.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: xbolva00, Quuxplusone, arthur.j.odwyer, cfe-commits

Differential Revision: https://reviews.llvm.org/D47067

llvm-svn: 333500
2018-05-30 03:53:16 +00:00
Peter Collingbourne 54d13b4068 Sema: Add a flag for rejecting member pointers with incomplete base types.
Codebases that need to be compatible with the Microsoft ABI can pass
this flag to avoid issues caused by the lack of a fixed ABI for
incomplete member pointers.

Differential Revision: https://reviews.llvm.org/D47503

llvm-svn: 333498
2018-05-30 03:40:04 +00:00
Eric Fiselier 92e523bf55 [Sema] Use %sub to cleanup overload diagnostics
Summary:
This patch adds the newly added `%sub` diagnostic modifier to cleanup repetition in the overload candidate diagnostics.

I think this should be good to go.

@rsmith: Some of the notes now emit `function template` where they only said `function` previously. It seems OK to me, but I would like your sign off on it.


Reviewers: rsmith, EricWF

Reviewed By: EricWF

Subscribers: cfe-commits, rsmith

Differential Revision: https://reviews.llvm.org/D47101

llvm-svn: 333485
2018-05-30 01:00:41 +00:00
Gor Nishanov 07ac63f89e [coroutines] Pass implicit object parameter to promise ctor (fix BUG37604)
Summary:
Complete the implementation of p0914r1.
Implicit object parameter should be passed to a promise constructor.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=37604

Reviewers: modocache, rsmith, lewissbaker

Reviewed By: modocache

Subscribers: cfe-commits, EricWF

Differential Revision: https://reviews.llvm.org/D47454

llvm-svn: 333379
2018-05-28 18:08:47 +00:00
Richard Smith 3e268632cf Use zeroinitializer for (trailing zero portion of) large array initializers
more reliably.

This re-commits r333044 with a fix for PR37560.

llvm-svn: 333141
2018-05-23 23:41:38 +00:00
Richard Smith 08b682bec1 Rework __builtin_classify_type support to better match GCC and to not assert on
unusual types.

Following the observed behavior of GCC, we now return -1 for vector types
(along with all of our extensions that GCC doesn't support), and for atomic
types we classify the underlying type.

GCC appears to have changed its classification for function and array arguments
between version 5 and version 6. Previously it would classify them as pointers
in C and as functions or arrays in C++, but from version 6 onwards, it
classifies them as pointers. We now follow the more recent GCC behavior rather
than emulating what I can only assume to be a historical bug in their C++
support for this builtin.

Finally, no version of GCC that I can find has ever used the "method"
classification for C++ pointers to member functions. Instead, GCC classifies
them as record types, presumably reflecting an internal implementation detail,
but whatever the reason we now produce compatible results.

llvm-svn: 333126
2018-05-23 21:18:00 +00:00
Hans Wennborg 156349fa10 Revert r333044 "Use zeroinitializer for (trailing zero portion of) large array initializers"
It caused asserts, see PR37560.

> Use zeroinitializer for (trailing zero portion of) large array initializers
> more reliably.
>
> Clang has two different ways it emits array constants (from InitListExprs and
> from APValues), and both had some ability to emit zeroinitializer, but neither
> was able to catch all cases where we could use zeroinitializer reliably. In
> particular, emitting from an APValue would fail to notice if all the explicit
> array elements happened to be zero. In addition, for large arrays where only an
> initial portion has an explicit initializer, we would emit the complete
> initializer (which could be huge) rather than emitting only the non-zero
> portion. With this change, when the element would have a suffix of more than 8
> zero elements, we emit the array constant as a packed struct of its initial
> portion followed by a zeroinitializer constant for the trailing zero portion.
>
> In passing, I found a bug where SemaInit would sometimes walk the entire array
> when checking an initializer that only covers the first few elements; that's
> fixed here to unblock testing of the rest.
>
> Differential Revision: https://reviews.llvm.org/D47166

llvm-svn: 333067
2018-05-23 08:24:01 +00:00
Richard Smith 9062bbf419 Use zeroinitializer for (trailing zero portion of) large array initializers
more reliably.

Clang has two different ways it emits array constants (from InitListExprs and
from APValues), and both had some ability to emit zeroinitializer, but neither
was able to catch all cases where we could use zeroinitializer reliably. In
particular, emitting from an APValue would fail to notice if all the explicit
array elements happened to be zero. In addition, for large arrays where only an
initial portion has an explicit initializer, we would emit the complete
initializer (which could be huge) rather than emitting only the non-zero
portion. With this change, when the element would have a suffix of more than 8
zero elements, we emit the array constant as a packed struct of its initial
portion followed by a zeroinitializer constant for the trailing zero portion.

In passing, I found a bug where SemaInit would sometimes walk the entire array
when checking an initializer that only covers the first few elements; that's
fixed here to unblock testing of the rest.

Differential Revision: https://reviews.llvm.org/D47166

llvm-svn: 333044
2018-05-23 00:09:29 +00:00
Richard Smith 3f1d6de4f7 Revert r332847; it caused us to miscompile certain forms of reference initialization.
llvm-svn: 332886
2018-05-21 20:36:58 +00:00
Serge Pavlov 9f8068420a [CodeGen] Recognize more cases of zero initialization
If a variable has an initializer, codegen tries to build its value. If
the variable is large in size, building its value requires substantial
resources. It causes strange behavior from user viewpoint: compilation
of huge zero initialized arrays like:

    char data_1[2147483648u] = { 0 };

consumes enormous amount of time and memory.

With this change codegen tries to determine if variable initializer is
equivalent to zero initializer. In this case variable value is not
constructed.

This change fixes PR18978.

Differential Revision: https://reviews.llvm.org/D46241

llvm-svn: 332847
2018-05-21 16:09:54 +00:00
Eric Fiselier b87be18d8e [Clang Tablegen][RFC] Allow Early Textual Substitutions in `Diagnostic` messages.
Summary:
There are cases where the same string or select is repeated verbatim in a lot of diagnostics. This can be a pain to maintain and update. Tablegen provides no way stash the common text somewhere and reuse it in the diagnostics, until now!

This patch allows diagnostic texts to contain `%sub{<definition-name>}`, where `<definition-name>` names a Tablegen record of type `TextSubstitution`. These substitutions are done early, before the diagnostic string is otherwise processed. All `%sub` modifiers will be replaced before the diagnostic definitions are emitted.

The substitution must specify all arguments used by the substitution, and modifier indexes in the substitution are re-numbered accordingly. For example:

```
def select_ovl_candidate : TextSubstitution<"%select{function|constructor}0%select{| template| %2}1">;
```
when used as
```
"candidate `%sub{select_ovl_candidate}3,2,1 not viable"
```
will act as if we wrote:
```
"candidate %select{function|constructor}3%select{| template| %1}2 not viable"
```

Reviewers: rsmith, rjmccall, aaron.ballman, a.sidorin

Reviewed By: rjmccall

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D46740

llvm-svn: 332799
2018-05-19 03:12:04 +00:00
Richard Smith fb50dd34ed Revert r332470 (and corresponding tests in r332492).
This regressed our support for __attribute__((section)). See added test file
for example of code broken by this.

llvm-svn: 332760
2018-05-18 20:18:17 +00:00
Nico Weber d60bbcee98 Fix __uuidof handling on non-type template parameter in C++17
Clang used to pass the base lvalue of a non-type template parameter
to the template instantiation phase when the base part is __uuidof
and it's running in C++17 mode.
However, that drops its LValuePath, and unintentionally transforms
&__uuidof(...) to __uuidof(...).

This CL fixes that by passing whole expr. Fixes PR24986.

https://reviews.llvm.org/D46820?id=146557
Patch from Taiju Tsuiki <tzik@chromium.org>!

llvm-svn: 332614
2018-05-17 15:26:37 +00:00
Erich Keane a3c0c9a2ba Add lit tests forgotten for R332470
I forgot to svn-add the lit tests for R332470.  
Added here!

llvm-svn: 332492
2018-05-16 17:04:47 +00:00
Joel E. Denny efdb9be29f [Attr] Don't print fake MSInheritance argument
This was discovered at:

http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20180514/228390.html

Reviewed by: aaron.ballman

Differential Revision: https://reviews.llvm.org/D46905

llvm-svn: 332481
2018-05-16 15:18:30 +00:00
Joel E. Denny 35a1ba87b9 Revert r332474: [Attr] Don't print fake MSInheritance argument
I botched the commit log attributes.

llvm-svn: 332480
2018-05-16 15:18:27 +00:00
Joel E. Denny dcbf2e8e65 [Attr] Don't print fake MSInheritance argument
This was discovered at:

http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20180514/228390.html

Reviewed by: aaron.ballman

https://reviews.llvm.org/D46905

llvm-svn: 332474
2018-05-16 14:51:18 +00:00
Richard Smith 5412b21d24 Fix 32-bit buildbots.
llvm-svn: 332425
2018-05-16 01:08:07 +00:00
Richard Smith 7bfd705492 Don't produce a redundant "auto type is incompatible with C++98" on every lambda with no explicit return type.
We already warned about the lambda, and we don't have a source location for the imagined "auto" anyway.

llvm-svn: 332401
2018-05-15 21:27:30 +00:00
Joel E. Denny ae7c944355 [AST] Fix printing tag decl groups in decl contexts
For example, given:

  struct T1 {
    struct T2 *p0;
  };

-ast-print produced:

  struct T1 {
    struct T2;
    struct T2 *p0;
  };

Compiling that produces a warning that the first struct T2 declaration
does not declare anything.

Details:

A tag decl group is one or more decls that share a type specifier that
is a tag decl (that is, a struct/union/class/enum decl).  Within
functions, the parser builds such a tag decl group as part of a
DeclStmt.  However, in decl contexts, such as file scope or a member
list, the parser does not group together the members of a tag decl
group.  Previously, detection of tag decl groups during printing was
implemented but only if the tag decl was unnamed.  Otherwise, as in
the above example, the members of the group did not print together and
so sometimes introduced warnings.

This patch extends detection of tag decl groups in decl contexts to
any tag decl that is recorded in the AST as not free-standing.

Reviewed by: rsmith

Differential Revision: https://reviews.llvm.org/D45465

llvm-svn: 332314
2018-05-15 00:44:14 +00:00
Richard Trieu a2b8fe6604 Enable control flow pruning of float overflow warnings.
Like other conversion warnings, allow float overflow warnings to be disabled
in known dead paths of template instantiation.  This often occurs when a
template template type is a numeric type and the template will check the
range of the numeric type before performing the conversion.

llvm-svn: 332310
2018-05-14 23:21:48 +00:00
Richard Smith d699da427a PR37450: Fix bug that disabled some type checks for variables with deduced types.
Also improve diagnostic for the case where a type is non-literal because it's a lambda.

llvm-svn: 332286
2018-05-14 20:15:04 +00:00
Richard Smith 7981004eb7 Improve diagnostics and error recovery for template name lookup.
For 'x::template y', consistently give a "no member named 'y' in 'x'"
diagnostic if there is no such member, and give a 'template keyword not
followed by a template' name error if there is such a member but it's not a
template. In the latter case, add a note pointing at the non-template.

Don't suggest inserting a 'template' keyword in 'X::Y<' if X is dependent
if the lookup of X::Y was actually not a dependent lookup and found only
non-templates.

llvm-svn: 332076
2018-05-11 02:43:08 +00:00
Reid Kleckner 1a840d29b4 Allow dllimport non-type template arguments in C++17
Summary:
Fixes PR35772.

Reviewers: rsmith

Differential Revision: https://reviews.llvm.org/D43320

llvm-svn: 332018
2018-05-10 18:57:35 +00:00
Erich Keane a4c48c68c5 Fix float->int conversion warnings when near barriers.
As Eli brought up here: https://reviews.llvm.org/D46535
I'd previously messed up this fix by missing conversions
that are just slightly outside the range.  This patch fixes
this by no longer ignoring the return value of 
convertToInteger.  Additionally, one of the error messages
wasn't very sensical (mentioning out of range value, when it 
really was not), so it was cleaned up as well.

llvm-svn: 331812
2018-05-08 21:26:21 +00:00
Eric Fiselier c5fb858053 [C++2a] Implement operator<=>: Address bugs and post-commit review comments after r331677.
This patch addresses some mostly trivial post-commit review comments received
on r331677.

Additionally, this patch fixes an assertion in `getNarrowingKind` caused by
the use of an uninitialized value from `checkThreeWayNarrowingConversion`.

llvm-svn: 331707
2018-05-08 00:52:19 +00:00
Richard Smith a6cede6d8e PR37352: mangle numbering for decomposition declarations.
In order to match our mangling scheme, use a different set of numbers for
decomposition declarations, and consider all binding names when forming the
numbering. This does not yet affect any mangled names we produce, because
local decomposition declarations can't yet have linkage, but a C++ standard
proposal to change that is currently being processed.

llvm-svn: 331692
2018-05-07 22:23:38 +00:00
Eric Fiselier 0683c0e68d [C++2a] Implement operator<=> CodeGen and ExprConstant
Summary:
This patch tackles long hanging fruit for the builtin operator<=> expressions. It is currently needs some cleanup before landing, but I want to get some initial feedback.

The main changes are:

* Lookup, build, and store the required standard library types and expressions in `ASTContext`. By storing them in ASTContext we don't need to store (and duplicate) the required expressions in the BinaryOperator AST nodes. 

* Implement [expr.spaceship] checking, including diagnosing narrowing conversions. 

* Implement `ExprConstant` for builtin spaceship operators.

* Implement builitin operator<=> support in `CodeGenAgg`. Initially I emitted the required comparisons using `ScalarExprEmitter::VisitBinaryOperator`, but this caused the operand expressions to be emitted once for every required cmp.

* Implement [builtin.over] with modifications to support the intent of P0946R0. See the note on `BuiltinOperatorOverloadBuilder::addThreeWayArithmeticOverloads` for more information about the workaround.




Reviewers: rsmith, aaron.ballman, majnemer, rnk, compnerd, rjmccall

Reviewed By: rjmccall

Subscribers: rjmccall, rsmith, aaron.ballman, junbuml, mgorny, cfe-commits

Differential Revision: https://reviews.llvm.org/D45476

llvm-svn: 331677
2018-05-07 21:07:10 +00:00
Erich Keane 7130a93934 Correct warning on Float->Integer conversions.
As identified and briefly discussed here:
https://bugs.llvm.org/show_bug.cgi?id=37305

Converting a floating point number to an integer type when
the integral part is out of the range of the integer type is
undefined behavior in C. Additionally, CodeGen emits an undef
in this situation.

HOWEVER, we've been giving a warning that says that the value is
changed. This patch corrects the warning to list that it is actually
undefined behavior.

Differential Revision: https://reviews.llvm.org/D46535

llvm-svn: 331673
2018-05-07 20:52:56 +00:00
Richard Smith b5a317fbf6 Non-zero-length bit-fields make a class non-empty.
This implements the rule intended by the standard (see LWG 2358)
and the rule intended by the Itanium C++ ABI (see
https://github.com/itanium-cxx-abi/cxx-abi/pull/51), and makes
Clang match the behavior of GCC, ICC, and MSVC.

A pedantic reading of both the standard and the ABI indicate that Clang
is currently technically correct, but that's not worth much when it's
clear that the wording is wrong in both those places.

This is an ABI break for classes that derive from a class that is empty
other than one or more unnamed non-zero-length bit-fields. Such cases
are expected to be rare, but -fclang-abi-compat=6 restores the old
behavior just in case.

Differential Revision: https://reviews.llvm.org/D45174

llvm-svn: 331620
2018-05-07 06:43:30 +00:00
Aaron Ballman b9a457af35 Allow writing calling convention attributes on function types.
Calling convention attributes notionally appertain to the function type -- they modify the mangling of the function, change the behavior of assignment operations, etc. This commit allows the calling convention attributes to be written in the type position as well as the declaration position.

llvm-svn: 331459
2018-05-03 15:33:50 +00:00
Richard Smith 3a8244df6f Implement P0482R2, support for char8_t type.
This is not yet part of any C++ working draft, and so is controlled by the flag
-fchar8_t rather than a -std= flag. (The GCC implementation is controlled by a
flag with the same name.)

This implementation is experimental, and will be removed or revised
substantially to match the proposal as it makes its way through the C++
committee.

llvm-svn: 331244
2018-05-01 05:02:45 +00:00
Richard Smith d186829093 Fix printing of reference-to-reference types.
Previously we would sometimes print these as 'T &&&' or even 'T &&&&'.

llvm-svn: 331137
2018-04-29 05:33:38 +00:00
Richard Smith 4ae767ba3d PR37275 packed attribute should not apply to base classes
Clang incorrectly applied the packed attribute to base classes. Per GCC's
documentation and as can be observed from its behavior, packed only applies to
members, not base classes.

This change is conditioned behind -fclang-abi-compat so that an ABI break can
be avoided by users if desired.

Differential Revision: https://reviews.llvm.org/D46218

llvm-svn: 331136
2018-04-29 04:55:46 +00:00
Richard Smith c08b693e30 Parse A::template B as an identifier rather than as a template-id with no
template arguments.

This fixes some cases where we'd incorrectly accept "A::template B" when B is a
kind of template that requires template arguments (in particular, a variable
template or a concept).

llvm-svn: 331013
2018-04-27 02:00:13 +00:00
Richard Smith 04100943da Diagnose missing template arguments for a variable template even when there is
a preceding 'template' keyword.

We only diagnose in the dependent case (wherein we used to crash). Another bug
prevents the diagnostic from appearing in the non-template case.

llvm-svn: 330894
2018-04-26 02:10:22 +00:00
Richard Smith ecad88d2bb Factor out common code for diagnosing missing template arguments.
In passing, add 'concept' to the list of template kinds in diagnostics.

llvm-svn: 330890
2018-04-26 01:08:00 +00:00
Aaron Ballman 93c6ba1d9d Improve -Warray-bounds to handle multiple array extents rather than only handling the top-most array extent.
Patch by Bevin Hansson.

llvm-svn: 330759
2018-04-24 19:21:04 +00:00
Benjamin Kramer bb156b52cf [AST] Another attempt at fixing the ARM bots.
llvm-svn: 330690
2018-04-24 08:18:32 +00:00
Benjamin Kramer 2fdf81fb2c [AST] Use a bit of trickery to make test pass on platforms where wchar_t is unsigned.
llvm-svn: 330689
2018-04-24 07:53:10 +00:00
Benjamin Kramer 33b7092601 [AST] strcmp/memcmp always compares unsigned chars.
This makes it return the right result in a couple of edge cases. The
wide versions always do the comparison on the underlying wchar_t type.

llvm-svn: 330656
2018-04-23 22:04:34 +00:00
Roman Lebedev 6ed0fad999 [Sema] Add -Wno-self-assign-overloaded
Summary:
It seems there isn't much enthusiasm for `-wtest` D45685.

This is more conservative version, which i had in the very first
revision of D44883, but that 'erroneously' got removed because of the review.

**Based on some [irc] discussions, it must really be documented that
we want all the new diagnostics to have their own flags, to ease
rollouts, transitions, etc.**

Please do note that i'm only adding `-Wno-self-assign-overloaded`,
but not `-Wno-self-assign-field-overloaded`, because i'm honestly
not aware of any false-positives from the `-field` variant,
but i can just as easily add it if wanted.
https://reviews.llvm.org/D44883#1068561

Reviewers: dblaikie, aaron.ballman, thakis, rjmccall, rsmith

Reviewed By: dblaikie

Subscribers: Quuxplusone, chandlerc, cfe-commits

Differential Revision: https://reviews.llvm.org/D45766

llvm-svn: 330651
2018-04-23 21:35:21 +00:00
Jan Korous 536d2e3072 [Sema] Disable built-in increment operator for bool in overload resolution in C++17
Following: https://llvm.org/svn/llvm-project/cfe/trunk@329804

For C++17 the wording of [over.built] p4 excluded bool:

For every pair (T , vq), where T is an arithmetic type other than bool, there exist
candidate operator functions of the form
  vq T & operator++(vq T &);
  T operator++(vq T &, int);

Differential Revision: https://reviews.llvm.org/D45569

llvm-svn: 330254
2018-04-18 13:38:39 +00:00
Aaron Ballman 81d07fc2c1 Fix the try_acquire_capability attribute to behave like the other try-lock functions. Fixes PR32954.
llvm-svn: 329930
2018-04-12 17:53:21 +00:00
Aaron Ballman 3399e50832 Correctly diagnose when a conversion function is declared with a type qualifier in the declaration specifiers rather than in the conversion type id. Fixes PR30595.
llvm-svn: 329924
2018-04-12 16:41:55 +00:00
Malcolm Parsons 321f24ec42 Diagnose cases of "return x" that should be "return std::move(x)" for efficiency
Summary:
This patch adds two new diagnostics, which are off by default:

**-Wreturn-std-move**

This diagnostic is enabled by `-Wreturn-std-move`, `-Wmove`, or `-Wall`.
Diagnose cases of `return x` or `throw x`, where `x` is the name of a local variable or parameter, in which a copy operation is performed when a move operation would have been available. The user probably expected a move, but they're not getting a move, perhaps because the type of "x" is different from the return type of the function.
A place where this comes up in the wild is `stdext::inplace_function<Sig, N>` which implements conversion via a conversion operator rather than a converting constructor; see https://github.com/WG21-SG14/SG14/issues/125#issue-297201412
Another place where this has come up in the wild, but where the fix ended up being different, was

    try { ... } catch (ExceptionType ex) {
        throw ex;
    }

where the appropriate fix in that case was to replace `throw ex;` with `throw;`, and incidentally to catch by reference instead of by value. (But one could contrive a scenario where the slicing was intentional, in which case throw-by-move would have been the appropriate fix after all.)
Another example (intentional slicing to a base class) is dissected in https://github.com/accuBayArea/Slides/blob/master/slides/2018-03-07.pdf

**-Wreturn-std-move-in-c++11**

This diagnostic is enabled only by the exact spelling `-Wreturn-std-move-in-c++11`.
Diagnose cases of "return x;" or "throw x;" which in this version of Clang *do* produce moves, but which prior to Clang 3.9 / GCC 5.1 produced copies instead. This is useful in codebases which care about portability to those older compilers.
The name "-in-c++11" is not technically correct; what caused the version-to-version change in behavior here was actually CWG 1579, not C++14. I think it's likely that codebases that need portability to GCC 4.9-and-earlier may understand "C++11" as a colloquialism for "older compilers." The wording of this diagnostic is based on feedback from @rsmith.

**Discussion**

Notice that this patch is kind of a negative-space version of Richard Trieu's `-Wpessimizing-move`. That diagnostic warns about cases of `return std::move(x)` that should be `return x` for speed. These diagnostics warn about cases of `return x` that should be `return std::move(x)` for speed. (The two diagnostics' bailiwicks do not overlap: we don't have to worry about a `return` statement flipping between the two states indefinitely.)

I propose to write a paper for San Diego that would relax the implicit-move rules so that in C++2a the user //would// see the moves they expect, and the diagnostic could be re-worded in a later version of Clang to suggest explicit `std::move` only "in C++17 and earlier." But in the meantime (and/or forever if that proposal is not well received), this diagnostic will be useful to detect accidental copy operations.

Reviewers: rtrieu, rsmith

Reviewed By: rsmith

Subscribers: lebedev.ri, Rakete1111, rsmith, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D43322

Patch by Arthur O'Dwyer.

llvm-svn: 329914
2018-04-12 14:48:48 +00:00
Jan Korous d74ebe22db [Sema] Fix built-in decrement operator overload resolution
C++ [over.built] p4:

"For every pair (T, VQ), where T is an arithmetic type other than bool, and VQ is either volatile or empty, there exist candidate operator functions of the form

  VQ T&      operator--(VQ T&);
  T          operator--(VQ T&, int);
"
The bool type is in position LastPromotedIntegralType in BuiltinOperatorOverloadBuilder::getArithmeticType::ArithmeticTypes, but addPlusPlusMinusMinusArithmeticOverloads() was expecting it at position 0.

Differential Revision: https://reviews.llvm.org/D44988

rdar://problem/34255516

llvm-svn: 329804
2018-04-11 13:36:29 +00:00
Akira Hatanaka 4e2698ca9e [ExprConstant] Use an AST node and a version number as a key to create
an APValue and retrieve it from map Temporaries.

The version number is needed when a single AST node is visited multiple
times and is used to create APValues that are required to be distinct
from each other (for example, MaterializeTemporaryExprs in default
arguments and VarDecls in loops).

rdar://problem/36505742

Differential Revision: https://reviews.llvm.org/D42776

llvm-svn: 329671
2018-04-10 05:15:01 +00:00
Eric Fiselier 4b8c991870 [Sema] Fix PR35832 - Ambiguity accessing anonymous struct/union with multiple bases.
Summary:
Currently clang doesn't do qualified lookup when building indirect field decl references. This causes ambiguity when the field is in a base class to which there are multiple valid paths  even though a qualified name is used.

For example:
```
class B {
protected:
 int i;
 union { int j; };
};

class X : public B { };
class Y : public B { };

class Z : public X, public Y {
 int a() { return X::i; } // works
 int b() { return X::j; } // fails
};
```

Reviewers: rsmith, aaron.ballman, rjmccall

Reviewed By: rjmccall

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D45411

llvm-svn: 329521
2018-04-08 06:21:33 +00:00
Eric Fiselier 80440deed4 Revert "[Sema] Fix PR35832 - Ambiguity accessing anonymous struct/union with multiple bases."
This reverts commit r329519. There are some unaddressed test failures.

llvm-svn: 329520
2018-04-08 06:05:33 +00:00
Eric Fiselier 35177d0fec [Sema] Fix PR35832 - Ambiguity accessing anonymous struct/union with multiple bases.
Summary:
Currently clang doesn't do qualified lookup when building indirect field decl references. This causes ambiguity when the field is in a base class to which there are multiple valid paths  even though a qualified name is used.

For example:
```
class B {
protected:
 int i;
 union { int j; };
};

class X : public B { };
class Y : public B { };

class Z : public X, public Y {
 int a() { return X::i; } // works
 int b() { return X::j; } // fails
};
```

Reviewers: rsmith, aaron.ballman, rjmccall

Reviewed By: rjmccall

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D45411

llvm-svn: 329519
2018-04-08 05:50:01 +00:00
Eric Fiselier 84393619eb [Sema] Fix PR22637 - IndirectFieldDecl's discard qualifiers during template instantiation.
Summary:
Currently Clang fails to propagate qualifiers from the `CXXThisExpr` to the rebuilt `FieldDecl` for IndirectFieldDecls. For example:

```
template <class T> struct Foo {
  struct { int x; };
  int y;
  void foo() const { 
      static_assert(__is_same(int const&, decltype((y))));
      static_assert(__is_same(int const&, decltype((x)))); // assertion fails
  }
};
template struct Foo<int>;
```

The fix is to delegate rebuilding of the MemberExpr to `BuildFieldReferenceExpr` which correctly propagates the qualifiers.

Reviewers: rsmith, lebedev.ri, aaron.ballman, bkramer, rjmccall

Reviewed By: rjmccall

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D45412

llvm-svn: 329517
2018-04-08 05:11:59 +00:00
Roman Lebedev 61061d69ea [Sema] Extend -Wself-assign and -Wself-assign-field to warn on overloaded self-assignment (classes)
Summary:
This has just bit me, so i though it would be nice to avoid that next time :)
Motivational case:
  https://godbolt.org/g/cq9UNk
Basically, it's likely to happen if you don't like shadowing issues,
and use `-Wshadow` and friends. And it won't be diagnosed by clang.

The reason is, these self-assign diagnostics only work for builtin assignment
operators. Which makes sense, one could have a very special operator=,
that does something unusual in case of self-assignment,
so it may make sense to not warn on that.

But while it may be intentional in some cases, it may be a bug in other cases,
so it would be really great to have some diagnostic about it...

Reviewers: aaron.ballman, rsmith, rtrieu, nikola, rjmccall, dblaikie

Reviewed By: rjmccall

Subscribers: EricWF, lebedev.ri, thakis, Quuxplusone, cfe-commits

Differential Revision: https://reviews.llvm.org/D44883

llvm-svn: 329493
2018-04-07 10:39:21 +00:00
Alexander Kornienko 2a8c18d991 Fix typos in clang
Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:

  archtype
  cas
  classs
  checkk
  compres
  definit
  frome
  iff
  inteval
  ith
  lod
  methode
  nd
  optin
  ot
  pres
  statics
  te
  thru

Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)

Differential revision: https://reviews.llvm.org/D44188

llvm-svn: 329399
2018-04-06 15:14:32 +00:00
Richard Smith b6070db0d0 DR1672, DR1813, DR1881, DR2120: Implement recent fixes to "standard
layout" rules.

The new rules say that a standard-layout struct has its first non-static
data member and all base classes at offset 0, and consider a class to
not be standard-layout if that would result in multiple subobjects of a
single type having the same address.

We track "is C++11 standard-layout class" separately from "is
standard-layout class" so that the ABIs that need this information can
still use it.

Differential Revision: https://reviews.llvm.org/D45176

llvm-svn: 329332
2018-04-05 18:55:37 +00:00
Erik Pilkington 11232912b1 [AST] Don't track lambda captures when checking a potential constant expression.
Fixes PR36054.

Differential revision: https://reviews.llvm.org/D45194

llvm-svn: 329244
2018-04-05 00:12:05 +00:00
Brian Gesiak cb02402489 [Coroutines] Find custom allocators in class scope
Summary:
https://reviews.llvm.org/rL325291 implemented Coroutines TS N4723
section [dcl.fct.def.coroutine]/7, but it performed lookup of allocator
functions within both the global and class scope, whereas the specified
behavior is to perform lookup for custom allocators within just the
class scope.

To fix, add parameters to the `Sema::FindAllocationFunctions` function
such that it can be used to lookup allocators in global scope,
class scope, or both (instead of just being able to look up in just global
scope or in both global and class scope). Then, use those parameters
from within the coroutine Sema.

This incorrect behavior had the unfortunate side-effect of causing the
bug https://bugs.llvm.org/show_bug.cgi?id=36578 (or at least the reports
of that bug in C++ programs). That bug would occur for any C++ user with
a coroutine frame that took a single pointer argument, since it would
then find the global placement form `operator new`, described in the
C++ standard 18.6.1.3.1. This patch prevents Clang from generating code
that triggers the LLVM assert described in that bug report.

Test Plan: `check-clang`

Reviewers: GorNishanov, eric_niebler, lewissbaker

Reviewed By: GorNishanov

Subscribers: EricWF, cfe-commits

Differential Revision: https://reviews.llvm.org/D44552

llvm-svn: 328949
2018-04-01 22:59:22 +00:00
Richard Trieu b402580616 Fix some handling of AST nodes with diagnostics.
The diagnostic system for Clang can already handle many AST nodes.  Instead
of converting them to strings first, just hand the AST node directly to
the diagnostic system and let it handle the output.  Minor changes in some
diagnostic output.

llvm-svn: 328688
2018-03-28 04:16:13 +00:00
Volodymyr Sapsai ca7902f7d2 [Sema] Emit -Winteger-overflow for arguments in function calls, ObjC messages.
rdar://problem/35539384

Reviewers: ahatanak, nicholas, rsmith, jkorous-apple

Reviewed By: jkorous-apple

Subscribers: cfe-commits, jkorous-apple

Differential Revision: https://reviews.llvm.org/D42938

llvm-svn: 328671
2018-03-27 21:29:05 +00:00
Gor Nishanov d4507266c8 [coroutines] Do not attempt to typo-correct when coroutine is looking for required members
When SemaCoroutine looks for await_resume, it means it. No need for helpful: "Did you mean await_ready?" messages.

Fixes PR33477 and a couple of FIXMEs in test/SemaCXX/coroutines.cpp

llvm-svn: 328663
2018-03-27 20:38:19 +00:00
Eric Fiselier 855c09221a [coroutines] Fix unused warning on result of co_yield.
This patch follows up on r328602, which fixed the spurious unused
result warning for `co_await`.

llvm-svn: 328607
2018-03-27 03:33:06 +00:00
Eric Fiselier d2e30d34b9 [coroutines] Fix invalid source range in co_await call expressions.
Summary:
Currently an invalid source range is generated for the member call expressions of `co_await`. The end location of the call expression is the `co_await` token loc, while the start is the location of the operand. This causes crashes when the source range is used to produce diagnostics.

This patch fixes the issues by using the expression location instead of the token location when building the member calls.

Reviewers: GorNishanov, rsmith, vsk, aaron.ballman

Reviewed By: vsk

Subscribers: cfe-commits, modocache

Differential Revision: https://reviews.llvm.org/D44915

llvm-svn: 328606
2018-03-27 03:15:46 +00:00
Eric Fiselier 16269a83ec Fix unused expression warning in co_await.
Previously, anytime the result of the resume expression in
operator co_await was unused, a warning was generated. This
patch fixes the issue by only generating the unused result warning
if calling `await_resume()` would also generate a warning.

llvm-svn: 328602
2018-03-27 00:58:16 +00:00
Eric Fiselier f3d421280b Fix test failure on Windows caused by different underlying enumeration type rules
llvm-svn: 328243
2018-03-22 21:17:07 +00:00
Robert Widmann 97608445b1 Improve -Winfinite-recursion
Summary: Rewrites -Winfinite-recursion to remove the state dictionary and explore paths in loops - especially infinite loops.  The new check now detects recursion in loop bodies dominated by a recursive call.

Reviewers: rsmith, rtrieu

Reviewed By: rtrieu

Subscribers: lebedev.ri, cfe-commits

Differential Revision: https://reviews.llvm.org/D43737

llvm-svn: 328173
2018-03-22 03:16:23 +00:00
Eric Fiselier fa752f23cc [Builtins] Overload __builtin_operator_new/delete to allow forwarding to usual allocation/deallocation functions.
Summary:
Libc++'s default allocator uses `__builtin_operator_new` and `__builtin_operator_delete` in order to allow the calls to new/delete to be ellided. However, libc++ now needs to support over-aligned types in the default allocator. In order to support this without disabling the existing optimization Clang needs to support calling the aligned new overloads from the builtins.

See llvm.org/PR22634 for more information about the libc++ bug.

This patch changes `__builtin_operator_new`/`__builtin_operator_delete` to call any usual `operator new`/`operator delete` function. It does this by performing overload resolution with the arguments passed to the builtin to determine which allocation function to call. If the selected function is not a usual allocation function a diagnostic is issued.

One open issue is if the `align_val_t` overloads should be considered "usual" when `LangOpts::AlignedAllocation` is disabled.


In order to allow libc++ to detect this new behavior the value for `__has_builtin(__builtin_operator_new)` has been updated to `201802`.

Reviewers: rsmith, majnemer, aaron.ballman, erik.pilkington, bogner, ahatanak

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D43047

llvm-svn: 328134
2018-03-21 19:19:48 +00:00
Richard Smith c660c8f5d2 Implement C++ DR727, which permits explicit specializations at class scope.
More generally, this permits a template to be specialized in any scope in which
it could be defined, so this also supersedes DR44 and DR374 (the latter of
which we previously only implemented in C++11 mode onwards due to unclarity as
to whether it was a DR).

llvm-svn: 327705
2018-03-16 13:36:56 +00:00
Richard Trieu f4a0e9a78c [CFG] Allow CallExpr's to be looked up in CFG's
r327343 changed the handling for CallExpr in a CFG, which prevented lookups for
CallExpr while other Stmt kinds still worked.  This change carries over the
necessary bits from Stmt function to CallExpr function.

llvm-svn: 327593
2018-03-15 00:09:26 +00:00
Roman Lebedev fdf39fa4bf [Parser] (C++) Make -Wextra-semi slightly more useful
Summary:
Let's suppose the `-Weverything` is passed.

Given code like
```
void F() {}
;
```
If the code is compiled with `-std=c++03`, it would diagnose that extra sema:
```
<source>:2:1: warning: extra ';' outside of a function is a C++11 extension [-Wc++11-extra-semi]
;
^~
```
If the code is compiled with `-std=c++11`, it also would diagnose that extra sema:
```
<source>:2:1: warning: extra ';' outside of a function is incompatible with C++98 [-Wc++98-compat-pedantic]
;
^~
```

But, let's suppose the C++11 or higher is used, and the used does not care
about `-Wc++98-compat-pedantic`, so he disables that diagnostic.
And that silences the complaint about extra `;` too.
And there is no way to re-enable that particular diagnostic, passing `-Wextra-semi` does nothing...

Now, there is also a related `no newline at end of file` diagnostic, which is also emitted by `-Wc++98-compat-pedantic`
```
<source>:2:2: warning: C++98 requires newline at end of file [-Wc++98-compat-pedantic]
;
 ^
```
But unlike the previous case, if `-Wno-c++98-compat-pedantic` is passed, that diagnostic stays displayed:
```
<source>:2:2: warning: no newline at end of file [-Wnewline-eof]
;
 ^
```

This diff refactors the code so `-Wc++98-compat-extra-semi` can be re-enabled, after the `-Wc++98-compat-pedantic` was disabled.
This seems ugly, but there does not seem to be any saner way.

Testing: `$ ninja check-clang`

Reviewers: rsmith, rtrieu, aaron.ballman

Reviewed By: aaron.ballman

Subscribers: jordan_rose, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D43162

llvm-svn: 327558
2018-03-14 19:31:34 +00:00
Richard Smith 69cf59ed26 PR36645: Go looking for an appropriate array bound when constant-evaluating a
name of an array object.

llvm-svn: 327099
2018-03-09 02:00:01 +00:00
Reid Kleckner b2da086103 Push a function scope when parsing function bodies without a declaration
Summary:
This is PR36536.

There are a few ways to reach Sema::ActOnStartOfFunctionDef with a null
Decl. Currently, the parser continues on to attempt to parse the
statements in the function body without pushing a function scope or
declaration context. However, lots of statement parsing logic relies on
getCurFunction() returning something reasonable. It turns out that
getCurFunction() will never return null today because of an optimization
where Sema pre-allocates one FunctionScopeInfo and reuses it when
possible. This goes wrong when something inside the function body causes
us to push another function scope, such as requiring an implicit
definition of a special member function. Reusing the state clears it
out, which will lead to bugs. In PR36536, we found that the SwitchStack
gets unbalanced, because we push a switch, clear out the stack, and then
try to pop a switch that isn't there.

As a follow-up, I plan to move the pre-allocated FunctionScopeInfo out
of the FunctionScopes stack. This means the FunctionScopes stack will
often be empty, and callers of getCurFunction() will need to check for
null.

Reviewers: thakis

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D43980

llvm-svn: 326926
2018-03-07 18:55:10 +00:00
Serge Pavlov e6e534ca22 Function definition may have uninstantiated body
Current implementation of `FunctionDecl::isDefined` does not take into
account redeclarations that do not have bodies, but the bodies can be
instantiated from corresponding templated definition. This behavior does
not allow to detect function redefinition in the cases where friend
functions is defined in class templates. For instance, the code:
```
    template<typename T> struct X { friend void f() {} };
    X<int> xi;
    void f() {}
```
compiles successfully but must fail due to redefinition of `f`. The
declaration of the friend `f` is created when the containing template
`X` is instantiated, but it does not have a body as per 14.5.4p4
because `f` is not odr-used.

With this change the function `Sema::CheckForFunctionRedefinition`
considers functions with uninstantiated bodies as definitions.

Differential Revision: https://reviews.llvm.org/D30170

llvm-svn: 326419
2018-03-01 07:04:11 +00:00
Volodymyr Sapsai e8f1ffb50a [ExprConstant] Fix crash when initialize an indirect field with another field.
When indirect field is initialized with another field, you have
MemberExpr with CXXThisExpr that corresponds to the field's immediate
anonymous parent. But 'this' was referring to the non-anonymous parent.
So when we were building LValue Designator, it was incorrect as it had
wrong starting point. Usage of such designator would cause unexpected
APValue changes and crashes.

The fix is in adjusting 'this' for indirect fields from non-anonymous
parent to the field's immediate parent.

Discovered by OSS-Fuzz:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4985

rdar://problem/36359187

Reviewers: rsmith, efriedma

Reviewed By: rsmith

Subscribers: cfe-commits, jkorous-apple

Differential Revision: https://reviews.llvm.org/D42498

llvm-svn: 325997
2018-02-23 23:59:20 +00:00
Rafael Espindola 922f2aa9b2 Bring r325915 back.
The tests that failed on a windows host have been fixed.

Original message:

Start setting dso_local for COFF.

With this there are still some GVs where we don't set dso_local
because setGVProperties is never called. I intend to fix that in
followup commits. This is just the bare minimum to teach
shouldAssumeDSOLocal what it should do for COFF.

llvm-svn: 325940
2018-02-23 19:30:48 +00:00
Richard Smith 9ff1bfe480 Add a test to ensure we don't permit mutable access on temporaries outside the evaluation in which they were created.
llvm-svn: 325854
2018-02-23 02:03:26 +00:00
Hiroshi Inoue 971514dd3e [NFC] fix trivial typos in comments
"a a"->"a"

llvm-svn: 325753
2018-02-22 07:49:13 +00:00
Richard Smith 9defb7d6b1 In C++14 onwards, it is permitted to read mutable members in constant
expressions, if their lifetime began during the evaluation of the expression.

This is technically not allowed in C++11, though we could consider permitting
it there too, as an extension.

llvm-svn: 325663
2018-02-21 03:38:30 +00:00
Richard Smith 0848210b74 Fix some -Wexceptions false positives.
Reimplement the "noexcept function actually throws" warning to properly handle
nested try-blocks. In passing, change 'throw;' handling to treat any enclosing
try block as being sufficient to suppress the warning rather than requiring a
'catch (...)'; the warning is intended to be conservatively-correct.

llvm-svn: 325545
2018-02-20 02:32:30 +00:00
Erich Keane 29636aaaa6 Clean up 'target' attribute diagnostics
There were a few issues previously with the target
attribute diagnostics implementation that lead to the
attribute being added to the AST despite having an error
in it.

This patch changes that, and adds a test to ensure it
does not get added to the AST.

Differential Revision: https://reviews.llvm.org/D43359

llvm-svn: 325364
2018-02-16 17:31:59 +00:00
Brian Gesiak 521b13b001 [Coroutines] Use target-agnostic size_t in test
Summary:
Fix a test failure on ARM hosts that was caused by a difference in the type of
size_t, by using a target-agnostic definiton.

Test Plan:
```
clang -cc1 -internal-isystem build/lib/clang/7.0.0/include -nostdsysteminc \
      -std=c++14 -fcoroutines-ts -verify clang/test/SemaCXX/coroutines.cpp \
      -fcxx-exceptions -fexceptions \
      -triple armeb-none-eabi
```

llvm-svn: 325342
2018-02-16 14:11:27 +00:00
Hans Wennborg 02d3361c38 Revert r325321 "[Sema] Take into account the current context when checking the"
This broke the Chromium build, see https://crbug.com/813017

> accessibility of a class member.
>
> This fixes PR32898.
>
> rdar://problem/33737747
>
> Differential revision: https://reviews.llvm.org/D36918

llvm-svn: 325335
2018-02-16 12:06:32 +00:00
Akira Hatanaka 82443d365f [Sema] Take into account the current context when checking the
accessibility of a class member.

This fixes PR32898.

rdar://problem/33737747

Differential revision: https://reviews.llvm.org/D36918

llvm-svn: 325321
2018-02-16 08:47:37 +00:00
Brian Gesiak 986062219f [Coroutines] Use allocator overload when available
Summary:
Depends on https://reviews.llvm.org/D42605.

An implementation of the behavior described in `[dcl.fct.def.coroutine]/7`:
when a promise type overloads `operator new` using a "placement new"
that takes the same argument types as the coroutine function, that
overload is used when allocating the coroutine frame.

Simply passing references to the coroutine function parameters directly
to `operator new` results in invariant violations in LLVM's coroutine
splitting pass, so this implementation modifies Clang codegen to
produce allocator-specific alloc/store/loads for each parameter being
forwarded to the allocator.

Test Plan: `check-clang`

Reviewers: rsmith, GorNishanov, eric_niebler

Reviewed By: GorNishanov

Subscribers: lewissbaker, EricWF, cfe-commits

Differential Revision: https://reviews.llvm.org/D42606

llvm-svn: 325291
2018-02-15 20:37:22 +00:00