user interface and documentation, and update __cplusplus for C++20.
WG21 considers the C++20 standard to be finished (even though it still
has some more steps to pass through in the ISO process).
The old flag names are accepted for compatibility, as usual, and we
still have lots of references to C++2a in comments and identifiers;
those can be cleaned up separately.
and objects with mutable subobjects.
The standard wording doesn't really cover these cases; accepting all
such cases seems most in line with what we do in other cases and what
other compilers do. (Essentially this means we're assuming that objects
external to the evaluation are always in-lifetime.)
The C++ rules briefly allowed this, but the rule changed nearly 10 years
ago and we never updated our implementation to match. However, we've
warned on this by default for a long time, and no other compiler accepts
(even as an extension).
1) Fix a regression in llvmorg-11-init-2485-g0e3a4877840 that would
reject some cases where a class name is shadowed by a typedef-name
causing a destructor declaration to be rejected. Prefer a tag type over
a typedef in destructor name lookup.
2) Convert the "type in destructor declaration is a typedef" error to an
error-by-default ExtWarn to allow codebases to turn it off. GCC and MSVC
do not enforce this rule.
Also add extension warnings for the cases that are disallowed by the
current rules for destructor name lookup, refactor and simplify the
lookup code, and improve the diagnostic quality when lookup fails.
The special case we previously supported for converting
p->N::S<int>::~S() from naming a class template into naming a
specialization thereof is subsumed by a more general rule here (which is
also consistent with Clang's historical behavior and that of other
compilers): if we can't find a suitable S in N, also look in N::S<int>.
The extension warnings are off by default, except for a warning when
lookup for p->N::S::~T() looks for T in scope instead of in N (or N::S).
That seems sufficiently heinous to warn on by default, especially since
we can't support it for a dependent nested-name-specifier.
Summary:
Due to a recent (but retroactive) C++ rule change, only sufficiently
C-compatible classes are permitted to be given a typedef name for
linkage purposes. Add an enabled-by-default warning for these cases, and
rephrase our existing error for the case where we encounter the typedef
name for linkage after we've already computed and used a wrong linkage
in terms of the new rule.
Reviewers: rjmccall
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D74103
constant initialization.
Removing this zeroing regressed our code generation in a few cases, also
fixed here. We now compute whether a variable has constant destruction
even if it doesn't have a constant initializer, by trying to destroy a
default-initialized value, and skip emitting a trivial default
constructor for a variable even if it has non-trivial (but perhaps
constant) destruction.
Summary:
Changes:
- Calls to consteval function are now evaluated in constant context but IR is still generated for them.
- Add diagnostic for taking address of a consteval function in non-constexpr context.
- Add diagnostic for address of consteval function accessible at runtime.
- Add tests
Reviewers: rsmith, aaron.ballman
Reviewed By: rsmith
Subscribers: mgrang, riccibruno, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D63960
Summary:
Clang -fpic defaults to -fno-semantic-interposition (GCC -fpic defaults
to -fsemantic-interposition).
Users need to specify -fsemantic-interposition to get semantic
interposition behavior.
Semantic interposition is currently a best-effort feature. There may
still be some cases where it is not handled well.
Reviewers: peter.smith, rnk, serge-sans-paille, sfertile, jfb, jdoerfert
Subscribers: dschuff, jyknight, dylanmckay, nemanjai, jvesely, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, arphaman, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73865
During the review of D73007 Aaron Puchert mentioned
`warn_for_range_variable_always_copy` shouldn't be part of -Wall since
some coding styles require `for(const auto &bar : bars)`. This warning
would cause false positives for these users. Based on Aaron's proposal
refactored the warnings:
* -Wrange-loop-construct warns about possibly unintended constructor
calls. This is part of -Wall. It contains
* warn_for_range_copy: loop variable A of type B creates a copy from
type C
* warn_for_range_const_reference_copy: loop variable A is initialized
with a value of a different type resulting in a copy
* -Wrange-loop-bind-reference warns about misleading use of reference
types. This is not part of -Wall. It contains
* warn_for_range_variable_always_copy: loop variable A is always a copy
because the range of type B does not return a reference
Differential Revision: https://reviews.llvm.org/D73434
Summary: Just like templates, they are excepted from the ODR rule.
Reviewed By: aaron.ballman, rsmith
Differential Revision: https://reviews.llvm.org/D68923
When used as qualified names, pseudo-destructors are always named as if
they were members of the type, never as members of the namespace
enclosing the type.
Summary:
`alloc_align` attribute takes parameter number, not the alignment itself,
so given **just** the attribute/function declaration we can't do any
sanity checking for said alignment.
However, at call site, given the actual `Expr` that is passed
into that parameter, we //might// be able to evaluate said `Expr`
as Integer Constant Expression, and perform the sanity checks.
But since there is no requirement for that argument to be an immediate,
we may fail, and that's okay.
However if we did evaluate, we should enforce the same constraints
as with `__builtin_assume_aligned()`/`__attribute__((assume_aligned(imm)))`:
said alignment is a power of two, and is not greater than our magic threshold
This was initially committed in c2a9061ac5
but reverted in 00756b1823 because of
suspicious bot failures.
Reviewers: erichkeane, aaron.ballman, hfinkel, rsmith, jdoerfert
Reviewed By: erichkeane
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72996
Summary:
I kind-of understand why it is restricted to integer-typed arguments,
for general enum's the value passed is not nessesairly the alignment implied,
although one might say that user would know best.
But we clearly should whitelist `std::align_val_t`,
which is just a thin wrapper over `std::size_t`,
and is the C++ standard way of specifying alignment.
Reviewers: erichkeane, rsmith, aaron.ballman, jdoerfert
Reviewed By: erichkeane
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73019
Summary:
`alloc_align` attribute takes parameter number, not the alignment itself,
so given **just** the attribute/function declaration we can't do any
sanity checking for said alignment.
However, at call site, given the actual `Expr` that is passed
into that parameter, we //might// be able to evaluate said `Expr`
as Integer Constant Expression, and perform the sanity checks.
But since there is no requirement for that argument to be an immediate,
we may fail, and that's okay.
However if we did evaluate, we should enforce the same constraints
as with `__builtin_assume_aligned()`/`__attribute__((assume_aligned(imm)))`:
said alignment is a power of two, and is not greater than our magic threshold
Reviewers: erichkeane, aaron.ballman, hfinkel, rsmith, jdoerfert
Reviewed By: erichkeane
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72996
This patch implements P1141R2 "Yet another approach for constrained declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in GetTypeSpecTypeForDeclarator, using the same logic
previously used for generic lambdas, now unified with abbreviated templates, by:
- Tracking the template parameter lists in the Declarator object
- Tracking the template parameter depth before parsing function declarators (at which point we can match template
parameters against scope specifiers to know if we have an explicit template parameter list to append invented parameters
to or not).
- When encountering an AutoType in a parameter context we check a stack of InventedTemplateParameterInfo structures that
contain the info required to create and accumulate invented template parameters (fields that were already present in
LambdaScopeInfo, which now inherits from this class and is looked up when an auto is encountered in a lambda context).
Resubmit after fixing MSAN failures caused by incomplete initialization of AutoTypeLocs in TypeSpecLocFiller.
Differential Revision: https://reviews.llvm.org/D65042
This patch implements P1141R2 "Yet another approach for constrained declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in GetTypeSpecTypeForDeclarator, using the same logic
previously used for generic lambdas, now unified with abbreviated templates, by:
- Tracking the template parameter lists in the Declarator object
- Tracking the template parameter depth before parsing function declarators (at which point we can match template
parameters against scope specifiers to know if we have an explicit template parameter list to append invented parameters
to or not).
- When encountering an AutoType in a parameter context we check a stack of InventedTemplateParameterInfo structures that
contain the info required to create and accumulate invented template parameters (fields that were already present in
LambdaScopeInfo, which now inherits from this class and is looked up when an auto is encountered in a lambda context).
Resubmit after incorrect check in NonTypeTemplateParmDecl broke lldb.
Differential Revision: https://reviews.llvm.org/D65042
This patch implements P1141R2 "Yet another approach for constrained declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in GetTypeSpecTypeForDeclarator, using the same logic
previously used for generic lambdas, now unified with abbreviated templates, by:
- Tracking the template parameter lists in the Declarator object
- Tracking the template parameter depth before parsing function declarators (at which point we can match template
parameters against scope specifiers to know if we have an explicit template parameter list to append invented parameters
to or not).
- When encountering an AutoType in a parameter context we check a stack of InventedTemplateParameterInfo structures that
contain the info required to create and accumulate invented template parameters (fields that were already present in
LambdaScopeInfo, which now inherits from this class and is looked up when an auto is encountered in a lambda context).
Differential Revision: https://reviews.llvm.org/D65042
When Wrange-loop-analysis issues a diagnostic on a dependent type in a
template the diagnostic may not be valid for all instantiations. Therefore
the diagnostic is suppressed during the instantiation. Non dependent types
still issue a diagnostic.
The same can happen when using macros. Therefore the diagnostic is
disabled for macros.
Fixes https://bugs.llvm.org/show_bug.cgi?id=44556
Differential Revision: https://reviews.llvm.org/D73007
This needs somewhat careful disambiguation, as C++2a explicit(bool) is a
breaking change. We only enable it in cases where the source construct
could not possibly be anything else.
We currently treat noexcept(not-convertible-to-bool) as 'none', which
results in the typeloc info being a different size, and causing an
assert later on in the process. In order to make recovery less
destructive, replace this with noexcept(false) and a constructed 'false'
expression.
Bug Report: https://bugs.llvm.org/show_bug.cgi?id=44514
Differential Revision: https://reviews.llvm.org/D72621
GCC supports the conditional operator on VectorTypes that acts as a
'select' in C++ mode. This patch implements the support. Types are
converted as closely to GCC's behavior as possible, though in a few
places consistency with our existing vector type support was preferred.
Note that this implementation is different from the OpenCL version in a
number of ways, so it unfortunately required a different implementation.
First, the SEMA rules and promotion rules are significantly different.
Secondly, GCC implements COND[i] != 0 ? LHS[i] : RHS[i] (where i is in
the range 0- VectorSize, for each element). In OpenCL, the condition is
COND[i] < 0 ? LHS[i]: RHS[i].
In the process of implementing this, it was also required to make the
expression COND ? LHS : RHS type dependent if COND is type dependent,
since the type is now dependent on the condition. For example:
T ? 1 : 2;
Is not typically type dependent, since the result can be deduced from
the operands. HOWEVER, if T is a VectorType now, it could change this
to a 'select' (basically a swizzle with a non-constant mask) with the 1
and 2 being promoted to vectors themselves.
While this is a change, it is NOT a standards incompatible change. Based
on my (and D. Gregor's, at the time of writing the code) reading of the
standard, the expression is supposed to be type dependent if ANY
sub-expression is type dependent.
Differential Revision: https://reviews.llvm.org/D71463
No longer generate a diagnostic when a small trivially copyable type is
used without a reference. Before the test looked for a POD type and had no
size restriction. Since the range-based for loop is only available in
C++11 and POD types are trivially copyable in C++11 it's not required to
test for a POD type.
Since copying a large object will be expensive its size has been
restricted. 64 bytes is a common size of a cache line and if the object is
aligned the copy will be cheap. No performance impact testing has been
done.
Differential Revision: https://reviews.llvm.org/D72212
The language wording change forgot to update overload resolution to rank
implicit conversion sequences based on qualification conversions in
reference bindings. The anticipated resolution for that oversight is
implemented here -- we order candidates based on qualification
conversion, not only on top-level cv-qualifiers, including ranking
reference bindings against non-reference bindings if they differ in
non-top-level qualification conversions.
For OpenCL/C++, this allows reference binding between pointers with
differing (nested) address spaces. This makes the behavior of reference
binding consistent with that of implicit pointer conversions, as is the
purpose of this change, but that pre-existing behavior for pointer
conversions is itself probably not correct. In any case, it's now
consistently the same behavior and implemented in only one place.
This reinstates commit de21704ba9,
reverted in commit d8018233d1, with
workarounds for some overload resolution ordering problems introduced by
CWG2352.
explicit functions that are not candidates.
It's not always obvious that the reason a conversion was not possible is
because the function you wanted to call is 'explicit', so explicitly say
if that's the case.
It would be nice to rank the explicit candidates higher in the
diagnostic if an implicit conversion sequence exists for their
arguments, but unfortunately we can't determine that without potentially
triggering non-immediate-context errors that we're not permitted to
produce.
This change introduces three new builtins (which work on both pointers
and integers) that can be used instead of common bitwise arithmetic:
__builtin_align_up(x, alignment), __builtin_align_down(x, alignment) and
__builtin_is_aligned(x, alignment).
I originally added these builtins to the CHERI fork of LLVM a few years ago
to handle the slightly different C semantics that we use for CHERI [1].
Until recently these builtins (or sequences of other builtins) were
required to generate correct code. I have since made changes to the default
C semantics so that they are no longer strictly necessary (but using them
does generate slightly more efficient code). However, based on our experience
using them in various projects over the past few years, I believe that adding
these builtins to clang would be useful.
These builtins have the following benefit over bit-manipulation and casts
via uintptr_t:
- The named builtins clearly convey the semantics of the operation. While
checking alignment using __builtin_is_aligned(x, 16) versus
((x & 15) == 0) is probably not a huge win in readably, I personally find
__builtin_align_up(x, N) a lot easier to read than (x+(N-1))&~(N-1).
- They preserve the type of the argument (including const qualifiers). When
using casts via uintptr_t, it is easy to cast to the wrong type or strip
qualifiers such as const.
- If the alignment argument is a constant value, clang can check that it is
a power-of-two and within the range of the type. Since the semantics of
these builtins is well defined compared to arbitrary bit-manipulation,
it is possible to add a UBSAN checker that the run-time value is a valid
power-of-two. I intend to add this as a follow-up to this change.
- The builtins avoids int-to-pointer casts both in C and LLVM IR.
In the future (i.e. once most optimizations handle it), we could use the new
llvm.ptrmask intrinsic to avoid the ptrtoint instruction that would normally
be generated.
- They can be used to round up/down to the next aligned value for both
integers and pointers without requiring two separate macros.
- In many projects the alignment operations are already wrapped in macros (e.g.
roundup2 and rounddown2 in FreeBSD), so by replacing the macro implementation
with a builtin call, we get improved diagnostics for many call-sites while
only having to change a few lines.
- Finally, the builtins also emit assume_aligned metadata when used on pointers.
This can improve code generation compared to the uintptr_t casts.
[1] In our CHERI compiler we have compilation mode where all pointers are
implemented as capabilities (essentially unforgeable 128-bit fat pointers).
In our original model, casts from uintptr_t (which is a 128-bit capability)
to an integer value returned the "offset" of the capability (i.e. the
difference between the virtual address and the base of the allocation).
This causes problems for cases such as checking the alignment: for example, the
expression `if ((uintptr_t)ptr & 63) == 0` is generally used to check if the
pointer is aligned to a multiple of 64 bytes. The problem with offsets is that
any pointer to the beginning of an allocation will have an offset of zero, so
this check always succeeds in that case (even if the address is not correctly
aligned). The same issues also exist when aligning up or down. Using the
alignment builtins ensures that the address is used instead of the offset. While
I have since changed the default C semantics to return the address instead of
the offset when casting, this offset compilation mode can still be used by
passing a command-line flag.
Reviewers: rsmith, aaron.ballman, theraven, fhahn, lebedev.ri, nlopes, aqjune
Reviewed By: aaron.ballman, lebedev.ri
Differential Revision: https://reviews.llvm.org/D71499
It turns out it is useful to be able to define the deref type as void.
In case we have a type erased owner, we want to express that the pointee
can be basically any type. It should not be unnatural to have a void
deref type as we already familiar with "pointers to void".
Differential Revision: https://reviews.llvm.org/D72097
This makes the range loop warnings part of -Wall.
Fixes PR32823: Warn about accidental coping of data in range based for
Differential Revision: https://reviews.llvm.org/D68912
Recomitted after fixing the warnings it created.
This makes the range loop warnings part of -Wall.
Fixes PR32823: Warn about accidental coping of data in range based for
Differential Revision: https://reviews.llvm.org/D68912
The Wrange-loop-analyses warns if a copy is made. Suppress this warning when
a temporary is bound to a rvalue reference.
While fixing this issue also found a copy-paste error in test6, which is also
fixed.
Differential Revision: https://reviews.llvm.org/D71806
msvc allows a subsequent declaration of a uuid attribute on a
struct/class. Mirror this behavior in clang-cl.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D71439
The current handling of the operators ||, && and ?: has a number of false
positive and false negative. The issues for operator || and && are:
1. We need to add sequencing regions for the LHS and RHS as is done for the
comma operator. Not doing so causes false positives in expressions like
`((a++, false) || (a++, false))` (from PR39779, see PR22197 for another
example).
2. In the current implementation when the evaluation of the LHS fails, the RHS
is added to a worklist to be processed later. This results in false negatives
in expressions like `(a && a++) + a`.
Fix these issues by introducing sequencing regions for the LHS and RHS, and by
not deferring the visitation of the RHS.
The issues with the ternary operator ?: are similar, with the added twist that
we should not warn on expressions like `(x ? y += 1 : y += 2)` since exactly
one of the 2nd and 3rd expression is going to be evaluated, but we should still
warn on expressions like `(x ? y += 1 : y += 2) = y`.
Differential Revision: https://reviews.llvm.org/D57747
Reviewed By: rsmith
C-style cast) to an enumeration type.
We previously forgot to check this, and happened to get away with it
(with bad diagnostics) only because we misclassified incomplete
enumeration types as not being unscoped enumeration types. This also
fixes the misclassification.
This covers:
* usual arithmetic conversions (comparisons, arithmetic, conditionals)
between different enumeration types
* usual arithmetic conversions between enums and floating-point types
* comparisons between two operands of array type
The deprecation warnings are on-by-default (in C++20 compilations); it
seems likely that these forms will become ill-formed in C++23, so
warning on them now by default seems wise.
For the first two bullets, off-by-default warnings were also added for
all the cases where we didn't already have warnings (covering language
modes prior to C++20). These warnings are in subgroups of the existing
-Wenum-conversion (except that the first case is not warned on if either
enumeration type is anonymous, consistent with our existing
-Wenum-conversion warnings).
Summary:
In https://reviews.llvm.org/D62550 @rsmith pointed out that there are
many situations in which a coroutine body statement may be
transformed/rebuilt as part of a template instantiation, and my naive
check whether the coroutine was a generic lambda was insufficient.
This is indeed true, as I've learned by reading more of the
TreeTransform code. Most transformations are written in a way that
doesn't assume the resulting types are not dependent types. So the
assertion in 'TransformCoroutineBodyStmt', that the promise type must no
longer be dependent, is out of place.
This patch removes the assertion, spruces up some code comments, and
adds a test that would have failed with my naive check from
https://reviews.llvm.org/D62550.
Reviewers: GorNishanov, rsmith, lewissbaker
Reviewed By: rsmith
Subscribers: junparser, EricWF, rsmith, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D70579
conservatively assuming they always can.
Also fix cases where we would not consider the computation of a VLA type
when determining whether an expression can throw. We don't yet properly
determine whether a VLA can throw, but no longer incorrectly claim it
can never throw.
Allow sending address spaces into diagnostics to simplify and improve
error reporting. Improved wording of diagnostics for address spaces
in overloading.
Tags: #clang
Differential Revision: https://reviews.llvm.org/D71111
This warning is supposed to be suppressed when the
constructor/destructor are non-trivial, since it might be a RAII type.
However, if the type has a trivial destructor and the constructor hasn't
been resolved (since it is called with dependent arguments), we were
still warning.
This patch suppresses the warning if the type could possibly have a
be a non-trivial constructor call. Note that this does not take the
arity of the constructors into consideration, so it might suppress
the warning in cases where it isn't possible to call a non-trivial
constructor.
In the presence of modules, we can have multiple lookup results for the
same entity, and we need to re-check for completeness each time we
consider a type.
forming non-type template parameter values.
This reverts commit 93cc9dddd8,
which reverted commit 11d1052785.
We now always form `&x` when forming a pointer to a function rather than
trying to use function-to-pointer decay. This matches the behavior of
the old code in this case, but not the intent as described by the
comments.
This reverts commit 11d1052785.
This change is problematic with function pointer template parameters. For
example, building libcxxabi with futexes (-D_LIBCXXABI_USE_FUTEX) produces this
diagnostic:
In file included from .../llvm-project/libcxxabi/src/cxa_guard.cpp:15:
.../llvm-project/libcxxabi/src/cxa_guard_impl.h:416:54: error: address of function 'PlatformThreadID' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]
has_thread_id_support(this->thread_id_address && GetThreadIDArg),
~~ ^~~~~~~~~~~~~~
.../llvm-project/libcxxabi/src/cxa_guard.cpp:38:26: note: in instantiation of member function '__cxxabiv1::(anonymous namespace)::InitByteFutex<&__cxxabiv1::(anonymous namespace)::PlatformFutexWait, &__cxxabiv1::(anonymous namespace)::PlatformFutexWake, &__cxxabiv1::(anonymous namespace)::PlatformThreadID>::InitByteFutex' requested here
SelectedImplementation imp(raw_guard_object);
^
.../llvm-project/libcxxabi/src/cxa_guard_impl.h:416:54: note: prefix with the address-of operator to silence this warning
has_thread_id_support(this->thread_id_address && GetThreadIDArg),
^
&
1 error generated.
The diagnostic is incorrect: adding the address-of operator also fails ("cannot
take the address of an rvalue of type 'uint32_t (*)()' (aka 'unsigned int
(*)()')").
If the lambda used 'this' without without capturing it, an error was
emitted, but the constant evaluator would still attempt to lookup the
capture, and failing to find it, dereference a null pointer.
This only happens in C++17 (as that's when lambdas were made
potentially-constexpr). Therefore, I also updated the
lambda-expressions.cpp test to run in both C++14 and C++17 modes.
This patch reapplies commit 759948467e. Patch was reverted due to a
clang-tidy test fail on Windows. The test has been modified. There
are no additional code changes.
Patch was tested with ninja check-all on Windows and Linux.
Summary of code changes:
Clang currently crashes for switch statements inside a template when the
condition is a non-integer field member because contextual implicit
conversion is skipped when parsing the condition. This conversion is
however later checked in an assert when the case statement is handled.
The conversion is skipped when parsing the condition because
the field member is set as type-dependent based on its containing class.
This patch sets the type dependency based on the field's type instead.
This patch fixes Bug 40982.
Summary:
GCC 9 added -Wdeprecated-copy (as part of -Wextra). This diagnostic is already implemented in Clang too, just hidden under -Wdeprecated (not on by default).
This patch adds -Wdeprecated-copy and makes it compatible with GCC 9+.
This diagnostic is heavily tested in deprecated.cpp, so I added simple tests just to check we warn when new flag/-Wextra is enabled.
Reviewers: rsmith, dblaikie
Reviewed By: dblaikie
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D70342
Summary:
The assertion of CoroutineParameterMoves happens when build coroutine function with arguments multiple time while fails to build promise type.
Fix: use return false instead.
Test Plan: check-clang
Reviewers: modocache, GorNishanov, rjmccall
Reviewed By: modocache
Subscribers: rjmccall, EricWF, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69022
Patch by junparser (JunMa)!
Some warnings in -Wtautological-compare subgroups are DefaultIgnore.
Adding this group to -Wmost, which is part of -Wall, will aid in their
discoverability.
Differential Revision: https://reviews.llvm.org/D69292
This patch reapplies commit 76945821b9. The first version broke
buildbots due to clang-tidy test fails. The fails are because some
errors in templates are now diagnosed earlier (does not wait till
instantiation). I have modified the tests to add checks for these
diagnostics/prevent these diagnostics. There are no additional code
changes.
Summary of code changes:
Clang currently crashes for switch statements inside a template when the
condition is a non-integer field member because contextual implicit
conversion is skipped when parsing the condition. This conversion is
however later checked in an assert when the case statement is handled.
The conversion is skipped when parsing the condition because
the field member is set as type-dependent based on its containing class.
This patch sets the type dependency based on the field's type instead.
This patch fixes Bug 40982.
Reviewers: rnk, gribozavr2
Patch by: Elizabeth Andrews (eandrews)
Differential revision: https://reviews.llvm.org/D69950
While here, wordsmith the error a bit. Now clang says:
error: filter expression has non-integral type 'Foo'
Fixes PR43779
Reviewers: amccarth
Differential Revision: https://reviews.llvm.org/D69969
Assume that the user knows what they're doing if they provide a char
literal as an array index. This more closely matches the behavior of
GCC.
Differential Revision: https://reviews.llvm.org/D58896
non-constant.
We previously failed the entire condition evaluation if an unmodeled
side-effect was encountered in an argument, even if that argument was
unused in the attribute's condition.
Summary:
This happens when someone initializes a variable with guaranteed copy
elision and an added const qualifier. Fixes PR43826.
Reviewers: aaron.ballman, rsmith
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D69533
Taking a value and the bitwise-or it with a non-zero constant will always
result in a non-zero value. In a boolean context, this is always true.
if (x | 0x4) {} // always true, intended '&'
This patch creates a new warning group -Wtautological-bitwise-compare for this
warning. It also moves in the existing tautological bitwise comparisons into
this group. A few other changes were needed to the CFGBuilder so that all bool
contexts would be checked. The warnings in -Wtautological-bitwise-compare will
be off by default due to using the CFG.
Fixes: https://bugs.llvm.org/show_bug.cgi?id=42666
Differential Revision: https://reviews.llvm.org/D66046
llvm-svn: 375318
This adds support for rewriting <, >, <=, and >= to a normal or reversed
call to operator<=>, for rewriting != to a normal or reversed call to
operator==, and for rewriting <=> and == to reversed forms of those same
operators.
Note that this is a breaking change for various C++17 code patterns,
including some in use in LLVM. The most common patterns (where an
operator== becomes ambiguous with a reversed form of itself) are still
accepted under this patch, as an extension (with a warning). I'm hopeful
that we can get the language rules fixed before C++20 ships, and the
extension warning is aimed primarily at providing data to inform that
decision.
llvm-svn: 375306
Summary:
We don't know what context to use until the classification result is
consumed by the parser, which could happen in a different semantic
context. So don't build the expression that results from name
classification until we get to that point and can handle it properly.
This covers everything except C++ implicit class member access, which
is a little awkward to handle properly in the face of the protected
member access check. But it at least fixes all the currently-filed
instances of PR43080.
Reviewers: efriedma
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D68896
llvm-svn: 374826
whose value is not ignored.
We don't warn on all the cases that are deprecated: specifically, we
choose to not warn for now if there are parentheses around the
assignment but its value is not actually used. This seems like a more
defensible rule, particularly for cases like sizeof(v = a), where the
parens are part of the operand rather than the sizeof syntax.
llvm-svn: 374135
Diagnose some now-deprecated uses of volatile types:
* as function parameter types and return types
* as the type of a structured binding declaration
* as the type of the lvalue operand of an increment / decrement /
compound assignment operator
This does not implement a check for the deprecation of simple
assignments whose results are used; that check requires somewhat
more complexity and will be addressed separately.
llvm-svn: 374133
same.
We were missing the lvalue-to-rvalue conversion entirely in this case,
and in fact still need the full CK_LValueToRValueBitCast conversion to
perform a load with no TBAA.
llvm-svn: 373874
Summary:
When using a user-defined conversion function template with a deduced return type the compiler gives a set of warnings:
```
bug.cc:252:44: error: cannot specify any part of a return type in the declaration of a conversion function; use an alias template to declare a conversion to 'auto (Ts &&...) const'
template <typename... Ts> operator auto()(Ts &&... xs) const;
^~~~~~~~~~~~~~~~~~~
bug.cc:252:29: error: conversion function cannot convert to a function type
template <typename... Ts> operator auto()(Ts &&... xs) const;
^
error: pointer to function type cannot have 'const' qualifier
```
after which it triggers an assertion failure. It seems the last error is incorrect and doesn't have any location information. This patch stops the compilation after the second warning.
Fixes bug 31422.
Patch by Mark de Wever!
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: bbannier, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64820
llvm-svn: 373862
pointer-to-member call can't determine a callee.
We will have produced a diagnostic already if the callee is known to be
unevaluatable, and diagnosing here rejects valid code during potential
constant expression checking.
llvm-svn: 373553
For now, we restrict this support to use from within the standard
library implementation, since we're required to make parts of the
standard library that use placement new work, but not permitted to
make uses of placement new from user code work.
llvm-svn: 373547
r368237 attempted to improve fix-its for move warnings, but introduced some
regressions to -Wpessimizing-move. Revert that change and add the missing
test cases to the pessimizing move test to prevent future regressions.
llvm-svn: 373421
Unlike the C++11 version, this one uese mutable state and dynamic
allocation instead of a carefully balanced and ever-accumulating pile of
temporaries.
llvm-svn: 373281
We used to miscompute the 'value-dependent' bit, and would crash if we
tried to evaluate a delete expression that should be value-dependent.
llvm-svn: 373272
constexpr) destructors from being used in the values of constexpr
variables.
The standard rules here are unclear at best, so rejecting the
problematic cases seems prudent. Prior to this change, we would fail to
run the destructors for these temporaries, even if they had
side-effects, which is certainly not the right behavior.
llvm-svn: 373161
In the presence of mutable state, we need to check whether temporaries
involved in a constant expression have permissible values at the end of
the overall evaluation, rather than at the end of the evaluation of the
initializer of the temporary.
llvm-svn: 373160
This matches how GCC handles it, see e.g. https://gcc.godbolt.org/z/HPplnl.
GCC documents the gnu_inline attribute with "In C++, this attribute does
not depend on extern in any way, but it still requires the inline keyword
to enable its special behavior."
The previous behaviour of gnu_inline in C++, without the extern
keyword, can be traced back to the original commit that added
support for gnu_inline, SVN r69045.
Differential Revision: https://reviews.llvm.org/D67414
llvm-svn: 373078
Summary: This patch fixes the __is_signed builtin type trait to work with floating point types and enums. Now, the builtin will return true if it is passed a floating point type and false for an enum type.
Reviewers: EricWF, rsmith, erichkeane, craig.topper, efriedma
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67897
llvm-svn: 372621
appropriate during constant evaluation.
Note that the evaluator is sometimes invoked on incomplete expressions.
In such cases, if an object is constructed but we never reach the point
where it would be destroyed (and it has non-trivial destruction), we
treat the expression as having an unmodeled side-effect.
llvm-svn: 372538
Summary: not every read in CXXConstructorDecl::getExplicitSpecifierInternal() was made on the canonical declaration.
Reviewers: rsmith, aaron.ballman
Reviewed By: rsmith
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67889
llvm-svn: 372530
APInt comparison require both to have the same bitwidth. Since only the value
is needed, use the compare function APInt::isSameValue instead.
llvm-svn: 372454
-Wtautological-overlap-compare and self-comparison from -Wtautological-compare
relay on detecting the same operand in different locations. Previously, each
warning had it's own operand checker. Now, both are merged together into
one function that each can call. The function also now looks through member
access and array accesses.
Differential Revision: https://reviews.llvm.org/D66045
llvm-svn: 372453
Allow this warning to detect a larger number of constant values, including
negative numbers, and handle non-int types better.
Differential Revision: https://reviews.llvm.org/D66044
llvm-svn: 372448
Exception specifiers are now part of the function type in C++17.
Normally, it is illegal to redeclare the same function or specialize a
template with a different exception specifier, but under
-fms-compatibility, we accept it with a warning. Without this change,
the function types would not match due to the exception specifier, and
clang would claim that the types were "incompatible". Now we emit the
warning and merge the redeclaration as we would in C++14 and earlier.
Fixes PR42842, which is about compiling _com_ptr_t in C++17.
Based on a patch by Alex Fusco <alexfusco@google.com>!
Differential Revision: https://reviews.llvm.org/D67590
llvm-svn: 372178
levels:
-- none: no lax vector conversions [new GCC default]
-- integer: only conversions between integer vectors [old GCC default]
-- all: all conversions between same-size vectors [Clang default]
For now, Clang still defaults to "all" mode, but per my proposal on
cfe-dev (2019-04-10) the default will be changed to "integer" as soon as
that doesn't break lots of testcases. (Eventually I'd like to change the
default to "none" to match GCC and general sanity.)
Following GCC's behavior, the driver flag -flax-vector-conversions is
translated to -flax-vector-conversions=integer.
This reinstates r371805, reverted in r371813, with an additional fix for
lldb.
llvm-svn: 371817
levels:
-- none: no lax vector conversions [new GCC default]
-- integer: only conversions between integer vectors [old GCC default]
-- all: all conversions between same-size vectors [Clang default]
For now, Clang still defaults to "all" mode, but per my proposal on
cfe-dev (2019-04-10) the default will be changed to "integer" as soon as
that doesn't break lots of testcases. (Eventually I'd like to change the
default to "none" to match GCC and general sanity.)
Following GCC's behavior, the driver flag -flax-vector-conversions is
translated to -flax-vector-conversions=integer.
llvm-svn: 371805
Summary:
C++ does not allow shadowing template parameters, but previously we
allowed it under -fms-extensions. Now this behavior is controlled by
-fms-compatibility, and we emit a -Wmicrosoft-template warning when it
happens.
Fixes PR43265
Reviewers: thakis, hans
Subscribers: amccarth, rsmith, STL_MSFT, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67463
llvm-svn: 371753
Summary:
This avoids a -Wignored-attribute warning on the code pattern Microsoft
recommends for integral const static data members defined in headers
here:
https://docs.microsoft.com/en-us/cpp/build/reference/microsoft-extensions-to-c-and-cpp?view=vs-2019
The attribute is redundant, but it is necessary when compiling in C++14
modes with /Za, which disables MSVC's extension that treats such
variables as implicitly inline.
Fixes PR43270
Reviewers: epastor, thakis, hans
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67426
llvm-svn: 371749
Summary:
Microsoft seems to do this regardless of the language mode, so we must
also do it in order to be ABI compatible.
Fixes PR36125
Reviewers: thakis
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D47956
llvm-svn: 371642
Reland after https://reviews.llvm.org/D66806 fixed the false-positive diagnostics.
Summary:
This fixes inference of gsl::Pointer on std::set::iterator with libstdc++ (the typedef for iterator
on the template is a DependentNameType - we can only put the gsl::Pointer attribute
on the underlaying record after instantiation)
inference of gsl::Pointer on std::vector::iterator with libc++ (the class was forward-declared,
we added the gsl::Pointer on the canonical decl (the forward decl), and later when the
template was instantiated, there was no attribute on the definition so it was not instantiated).
and a duplicate gsl::Pointer on some class with libstdc++ (we first added an attribute to
a incomplete instantiation, and then another was copied from the template definition
when the instantiation was completed).
We now add the attributes to all redeclarations to fix thos issues and make their usage easier.
Reviewers: gribozavr
Subscribers: Szelethus, xazax.hun, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66179
llvm-svn: 371182
This is mostly the same as the
[[clang::require_constant_initialization]] attribute, but has a couple
of additional syntactic and semantic restrictions.
In passing, I added a warning for the attribute form being added after
we have already seen the initialization of the variable (but before we
see the definition); that case previously slipped between the cracks and
the attribute was silently ignored.
llvm-svn: 370972
Breaks BUILD_SHARED_LIBS build, introduces cycles in library dependency
graphs. (clangInterp depends on clangAST which depends on clangInterp)
This reverts r370839, which is an yet another recommit of D64146.
llvm-svn: 370874
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.
Reviewers: Bigcheese, jfb, rsmith
Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64146
llvm-svn: 370839
Richard Smith