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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
This patch fixes clang to not consider braced initializers for
aggregate elements of arrays to be potentially dependent on the
indices of the initialized elements. Resolves bug 18978:
initialize a large static array = clang oom?
https://bugs.llvm.org/show_bug.cgi?id=18978
Differential Revision: https://reviews.llvm.org/D43187
llvm-svn: 325120
When we synthesize an implicit inner initializer list when analyzing an outer
initializer list, we add it to the outer list immediately, and then fill in the
inner list. This gives the outer list no chance to update its *-dependence bits
with those of the completed inner list. To fix this, re-add the inner list to
the outer list once it's completed.
Note that we do not recompute the *-dependence bits from scratch when we
complete an outer list; this would give the wrong result for the case where a
designated initializer overwrites a dependent initializer with a non-dependent
one. The resulting list in that case should still be dependent, even though all
traces of the dependence were removed from the semantic form.
llvm-svn: 324537
Summary:
Clang incorrectly reports empty unions as having a unique object representation. However, this is not correct since `sizeof(EmptyUnion) == 1` AKA it has 8 bits of padding. Therefore it should be treated the same as an empty struct and report `false`.
@erichkeane also suggested this fix should be merged into the 6.0 release branch, so the initial release of `__has_unique_object_representations` is as bug-free as possible.
Reviewers: erichkeane, rsmith, aaron.ballman, majnemer
Reviewed By: erichkeane
Subscribers: cfe-commits, erichkeane
Differential Revision: https://reviews.llvm.org/D42863
llvm-svn: 324134
Summary:
Use corutine function arguments to initialize a promise type, but only
if the promise type defines a constructor that takes those arguments.
Otherwise, fall back to the default constructor.
Test Plan: check-clang
Reviewers: rsmith, GorNishanov, eric_niebler
Reviewed By: GorNishanov
Subscribers: toby-allsopp, lewissbaker, EricWF, cfe-commits
Differential Revision: https://reviews.llvm.org/D41820
llvm-svn: 323381
Both are related to handling anonymous structures.
* clang didn't handle () around an anonymous struct variable.
* clang also crashed on syntax errors that could lead to other
syntactic constructs following the declaration of an
anonymous struct. While the code is invalid, that's not
a good reason to panic compiler.
Differential Revision: https://reviews.llvm.org/D41788
llvm-svn: 322742
When parsing C++ type construction expressions with list initialization,
forward the locations of the braces to Sema.
Without these locations, the code coverage pass crashes on the given test
case, because the pass relies on getLocEnd() returning a valid location.
Here is what this patch does in more detail:
- Forwards init-list brace locations to Sema (ParseExprCXX),
- Builds an InitializationKind with these locations (SemaExprCXX), and
- Uses these locations for constructor initialization (SemaInit).
The remaining changes fall out of introducing a new overload for
creating direct-list InitializationKinds.
Testing: check-clang, and a stage2 coverage-enabled build of clang with
asserts enabled.
Differential Revision: https://reviews.llvm.org/D41921
llvm-svn: 322729
We were trying to emit a diag::err_bad_multiversion_option diagnostic,
which expects an int as its first argument, with a string argument. As
it happens, the string `Feature` that was causing this was shadowing an
int `Feature` from the surrounding scope. :)
llvm-svn: 322530
While here, fix up the myriad other ways in which Sema's two "can this handler
catch that exception?" implementations get things wrong and unify them.
llvm-svn: 322431
Summary:
The STL types `std::pair` and `std::tuple` can both store reference types. However their constructors cannot adequately check if the initialization of reference types is safe. For example:
```
std::tuple<std::tuple<int> const&> t = 42;
// The stored reference is already dangling.
```
Libc++ has a best effort attempts in tuple to diagnose this, but they're not able to handle all valid cases (If I'm not mistaken). For example initialization of a reference from the result of a class's conversion operator. Libc++ would benefit from having a builtin traits which can provide a much better implementation.
This patch introduce the `__reference_binds_to_temporary(T, U)` trait that determines whether a reference of type `T` bound to an expression of type `U` would bind to a materialized temporary object.
Note that the trait simply returns false if `T` is not a reference type instead of reporting it as an error.
```
static_assert(__is_constructible(int const&, long));
static_assert(__reference_binds_to_temporary(int const&, long));
```
Reviewers: majnemer, rsmith
Reviewed By: rsmith
Subscribers: compnerd, cfe-commits
Differential Revision: https://reviews.llvm.org/D29930
llvm-svn: 322334
In C++17, guaranteed copy elision means that there isn't necessarily a
constructor call when a local variable is initialized by a function call that
returns a scoped_lockable by value. In order to model the effects of
initializing a local variable with a function call returning a scoped_lockable,
pretend that the move constructor was invoked within the caller at the point of
return.
llvm-svn: 322316
GCC's attribute 'target', in addition to being an optimization hint,
also allows function multiversioning. We currently have the former
implemented, this is the latter's implementation.
This works by enabling functions with the same name/signature to coexist,
so that they can all be emitted. Multiversion state is stored in the
FunctionDecl itself, and SemaDecl manages the definitions.
Note that it ends up having to permit redefinition of functions so
that they can all be emitted. Additionally, all versions of the function
must be emitted, so this also manages that.
Note that this includes some additional rules that GCC does not, since
defining something as a MultiVersion function after a usage has been made illegal.
The only 'history rewriting' that happens is if a function is emitted before
it has been converted to a multiversion'ed function, at which point its name
needs to be changed.
Function templates and virtual functions are NOT yet supported (not supported
in GCC either).
Additionally, constructors/destructors are disallowed, but the former is
planned.
llvm-svn: 322028
Check whether we are comparing the same entity, not merely the same
declaration, and don't assume that weak declarations resolve to distinct
entities.
llvm-svn: 321976
during template argument deduction.
We already did this when the injected-class-name was in P, but missed the case
where it was in A. This (probably) can't happen except in implicit deduction
guides.
llvm-svn: 321779
Summary:
The diagnostic was mostly introduced in D38101 by me, as a reaction to wasting a lot of time, see [[ https://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20171009/206427.html | mail ]].
However, the diagnostic is pretty dumb. While it works with no false-positives,
there are some questionable cases that are diagnosed when one would argue that they should not be.
The common complaint is that it diagnoses the comparisons between an `int` and
`long` when compiling for a 32-bit target as tautological, but not when
compiling for 64-bit targets. The underlying problem is obvious: data model.
In most cases, 64-bit target is `LP64` (`int` is 32-bit, `long` and pointer are
64-bit), and the 32-bit target is `ILP32` (`int`, `long`, and pointer are 32-bit).
I.e. the common pattern is: (pseudocode)
```
#include <limits>
#include <cstdint>
int main() {
using T1 = long;
using T2 = int;
T1 r;
if (r < std::numeric_limits<T2>::min()) {}
if (r > std::numeric_limits<T2>::max()) {}
}
```
As an example, D39149 was trying to fix this diagnostic in libc++, and it was not well-received.
This *could* be "fixed", by changing the diagnostics logic to something like
`if the types of the values being compared are different, but are of the same size, then do diagnose`,
and i even attempted to do so in D39462, but as @rjmccall rightfully commented,
that implementation is incomplete to say the least.
So to stop causing trouble, and avoid contaminating upcoming release, lets do this workaround:
* move these three diags (`warn_unsigned_always_true_comparison`, `warn_unsigned_enum_always_true_comparison`, `warn_tautological_constant_compare`) into it's own `-Wtautological-constant-in-range-compare`
* Disable them by default
* Make them part of `-Wextra`
* Additionally, give `warn_tautological_constant_compare` it's own flag `-Wtautological-type-limit-compare`.
I'm not happy about that name, but i can't come up with anything better.
This way all three of them can be enabled/disabled either altogether, or one-by-one.
Reviewers: aaron.ballman, rsmith, smeenai, rjmccall, rnk, mclow.lists, dim
Reviewed By: aaron.ballman, rsmith, dim
Subscribers: thakis, compnerd, mehdi_amini, dim, hans, cfe-commits, rjmccall
Tags: #clang
Differential Revision: https://reviews.llvm.org/D41512
llvm-svn: 321691
Previously, we would:
* compute the type of the conversion function and static invoker as a
side-effect of template argument deduction for a conversion
* re-compute the type as part of deduced return type deduction when building
the conversion function itself
Neither of these turns out to be quite correct. There are other ways to reach a
declaration of the conversion function than in a conversion (such as an
explicit call or friend declaration), and performing auto deduction causes the
function type to be rebuilt in the context of the lambda closure type (which is
different from the context in which it originally appeared, resulting in
spurious substitution failures for constructs that are valid in one context but
not the other, such as the use of an enclosing class's "this" pointer).
This patch switches us to use a different strategy: as before, we use the
declared type of the operator() to form the type of the conversion function and
invoker, but we now populate that type as part of return type deduction for the
conversion function. And the invoker is now treated as simply being an
implementation detail of building the conversion function, and isn't given
special treatment by template argument deduction for the conversion function
any more.
llvm-svn: 321683
(Re-submission of D39937 with fixed tests.)
Adjust wording for const-qualification mismatch to be a little more clear.
Also add another diagnostic for a ref qualifier mismatch, which previously produced a useless error (this error path is simply very old; see rL119336):
Before:
error: cannot initialize object parameter of type 'X0' with an expression of type 'X0'
After:
error: 'this' argument to member function 'rvalue' is an lvalue, but function has rvalue ref-qualifier
Reviewers: aaron.ballman
Reviewed By: aaron.ballman
Subscribers: lebedev.ri, cfe-commits
Differential Revision: https://reviews.llvm.org/D41646
llvm-svn: 321609
Summary:
Adjust wording for const-qualification mismatch to be a little more clear.
Also add another diagnostic for a ref qualifier mismatch, which previously produced a useless error (this error path is simply very old; see rL119336):
Before:
error: cannot initialize object parameter of type 'X0' with an expression of type 'X0'
After:
error: 'this' argument to member function 'rvalue' is an lvalue, but function has rvalue ref-qualifier
Reviewers: rsmith, aaron.ballman
Reviewed By: aaron.ballman
Subscribers: lebedev.ri, aaron.ballman, cfe-commits
Differential Revision: https://reviews.llvm.org/D39937
llvm-svn: 321592
This is a slightly odd construct (it's more common to see "A (::B)()") but can
happen in friend declarations, and the parens are not redundant as they prevent
the :: binding to the left.
llvm-svn: 321318
An unscoped enumeration used as template argument, should not have any
qualified information about its enclosing scope, as its visibility is
global.
In the case of scoped enumerations, they must include information
about their enclosing scope.
Patch by Carlos Alberto Enciso!
Differential Revision: https://reviews.llvm.org/D39239
llvm-svn: 321312
This allows you to dump C++ code that spells bool instead of _Bool, leaves off the elaborated type specifiers when printing struct or class names, and other C-isms.
Fixes the -Wreorder issue and fixes the ast-dump-color.cpp test.
llvm-svn: 321310
This allows you to dump C++ code that spells bool instead of _Bool, leaves off the elaborated type specifiers when printing struct or class names, and other C-isms.
llvm-svn: 321223
The initializeLocal function of UnaryTransformTypeLoc missed
the UnderlyingTInfo member. This caused a null-dereference
issue, as reported in PR23421. This patch correctly initializss
the UnderlyingTInfo.
llvm-svn: 320765
Summary:
In D41064, I proposed adding `#pragma clang diagnostic ignored
"-Wuser-defined-literals"` to some of libc++'s headers, since these
warnings are now triggered by clang's new `-std=gnu++14` default:
```
$ cat test.cpp
#include <string>
$ clang -std=c++14 -Wsystem-headers -Wall -Wextra -c test.cpp
In file included from test.cpp:1:
In file included from /usr/include/c++/v1/string:470:
/usr/include/c++/v1/string_view:763:29: warning: user-defined literal suffixes not starting with '_' are reserved [-Wuser-defined-literals]
basic_string_view<char> operator "" sv(const char *__str, size_t __len)
^
/usr/include/c++/v1/string_view:769:32: warning: user-defined literal suffixes not starting with '_' are reserved [-Wuser-defined-literals]
basic_string_view<wchar_t> operator "" sv(const wchar_t *__str, size_t __len)
^
/usr/include/c++/v1/string_view:775:33: warning: user-defined literal suffixes not starting with '_' are reserved [-Wuser-defined-literals]
basic_string_view<char16_t> operator "" sv(const char16_t *__str, size_t __len)
^
/usr/include/c++/v1/string_view:781:33: warning: user-defined literal suffixes not starting with '_' are reserved [-Wuser-defined-literals]
basic_string_view<char32_t> operator "" sv(const char32_t *__str, size_t __len)
^
In file included from test.cpp:1:
/usr/include/c++/v1/string:4012:24: warning: user-defined literal suffixes not starting with '_' are reserved [-Wuser-defined-literals]
basic_string<char> operator "" s( const char *__str, size_t __len )
^
/usr/include/c++/v1/string:4018:27: warning: user-defined literal suffixes not starting with '_' are reserved [-Wuser-defined-literals]
basic_string<wchar_t> operator "" s( const wchar_t *__str, size_t __len )
^
/usr/include/c++/v1/string:4024:28: warning: user-defined literal suffixes not starting with '_' are reserved [-Wuser-defined-literals]
basic_string<char16_t> operator "" s( const char16_t *__str, size_t __len )
^
/usr/include/c++/v1/string:4030:28: warning: user-defined literal suffixes not starting with '_' are reserved [-Wuser-defined-literals]
basic_string<char32_t> operator "" s( const char32_t *__str, size_t __len )
^
8 warnings generated.
```
Both @aaron.ballman and @mclow.lists felt that adding this workaround to
the libc++ headers was the wrong way, and it should be fixed in clang
instead.
Here is a proposal to do just that. I verified that this suppresses the
warning, even when -Wsystem-headers is used, and that the warning is
still emitted for a declaration outside of system headers.
Reviewers: aaron.ballman, mclow.lists, rsmith
Reviewed By: aaron.ballman
Subscribers: mclow.lists, aaron.ballman, andrew, emaste, cfe-commits
Differential Revision: https://reviews.llvm.org/D41080
llvm-svn: 320755
There are many more expr types that can be a capability expr, like
CXXThisExpr, CallExpr, MemberExpr. Instead of enumerating all of them,
just check typeHasCapability for any type given.
Also add & and * operators to allowed unary operators.
Differential Revision: https://reviews.llvm.org/D41224
llvm-svn: 320753
Adding the new enumerator forced a bunch more changes into this patch than I
would have liked. The -Wtautological-compare warning was extended to properly
check the new comparison operator, clang-format needed updating because it uses
precedence levels as weights for determining where to break lines (and several
operators increased their precedence levels with this change), thread-safety
analysis needed changes to build its own IL properly for the new operator.
All "real" semantic checking for this operator has been deferred to a future
patch. For now, we use the relational comparison rules and arbitrarily give
the builtin form of the operator a return type of 'void'.
llvm-svn: 320707
The two asserts are too aggressive. In C++ mode, an
enum is NOT considered an integral type, but an enum value
is allowed to be an enum. This patch relaxes the two asserts
to allow the enum value as well (as typechecking does).
llvm-svn: 320411
Summary:
This is a side-effect brought in by p0620r0, which allows other placeholder types (derived from `auto` and `decltype(auto)`) to be usable in a `new` expression with a single-clause //braced-init-list// as its initializer (8.3.4 [expr.new]/2). N3922 defined its semantics.
References:
http://wg21.link/p0620r0http://wg21.link/n3922
Reviewers: rsmith, aaron.ballman
Reviewed By: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D39451
llvm-svn: 320401
Summary:
Clang was crashing when diagnosing an unused-lambda-capture for a VLA because
From.getVariable() is null for the capture of a VLA bound.
Warning about the VLA bound capture is not helpful, so only warn for the VLA
itself.
Fixes: PR35555
Reviewers: aaron.ballman, dim, rsmith
Reviewed By: aaron.ballman, dim
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D41016
llvm-svn: 320396
and fold together into a single function.
In so doing, fix a handful of remaining bugs where we would report false
positives or false negatives if we promote a signed value to an unsigned type
for the comparison.
This re-commits r320122 and r320124, minus two changes:
* Comparisons between a constant and a non-constant expression of enumeration
type never warn, not even if the constant is out of range. We should be
warning about the creation of such a constant, not about its use.
* We do not use more precise bit-widths for comparisons against bit-fields.
The more precise diagnostics probably are the right thing, but we should
consider moving them under their own warning flag.
Other than the refactoring, this patch should only change the behavior for the
buggy cases (where the warnings didn't take into account that promotion from
signed to unsigned can leave a range of inaccessible values in the middle of
the promoted type).
llvm-svn: 320211
> Unify implementation of our two different flavours of -Wtautological-compare.
>
> In so doing, fix a handful of remaining bugs where we would report false
> positives or false negatives if we promote a signed value to an unsigned type
> for the comparison.
This caused a new warning in Chromium:
../../base/trace_event/trace_log.cc:1545:29: error: comparison of constant 64
with expression of type 'unsigned int' is always true
[-Werror,-Wtautological-constant-out-of-range-compare]
DCHECK(handle.event_index < TraceBufferChunk::kTraceBufferChunkSize);
~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'unsigned int' is really a 6-bit bitfield, which is why it's always
less than 64.
I thought we didn't use to warn (with out-of-range-compare) when comparing
against the boundaries of a type?
llvm-svn: 320162
In so doing, fix a handful of remaining bugs where we would report false
positives or false negatives if we promote a signed value to an unsigned type
for the comparison.
llvm-svn: 320122
This is a fix for PR35509 in which we crash because we attempt to compute the
alignment of an incomplete type.
Differential Revision: https://reviews.llvm.org/D40895
llvm-svn: 320017
Summary:
This feature was discussed but not yet proposed. It allows a structured binding to appear as a //condition//
if (auto [ok, val] = f(...))
So the user can save an extra //condition// if the statement can test the value to-be-decomposed instead. Formally, it makes the value of the underlying object of the structured binding declaration also the value of a //condition// that is an initialized declaration.
Considering its logicality which is entirely evident from its trivial implementation, I think it might be acceptable to land it as an extension for now before I write the paper.
Reviewers: rsmith, faisalv, aaron.ballman
Reviewed By: rsmith
Subscribers: aaron.ballman, cfe-commits
Differential Revision: https://reviews.llvm.org/D39284
llvm-svn: 320011
Richard Smith