This patch tries to implement RVO for coroutine's return object got from
get_return_object.
From [dcl.fct.def.coroutine]/p7 we could know that the return value of
get_return_object is either a reference or a prvalue. So it makes sense
to do copy elision for the return value. The return object should be
constructed directly into the storage where they would otherwise be
copied/moved to.
Test Plan: folly, check-all
Reviewed By: junparser
Differential revision: https://reviews.llvm.org/D117087
when the function declaration's return type is already invalid for
some reason. This is relevant to https://github.com/llvm/llvm-project/issues/49188
because another way that the declaration's return type could become
invalid is that it might be `C auto` where `C<void>` is false.
Differential Revision: https://reviews.llvm.org/D119094
These changes make the Clang parser recognize expression parameter pack
expansion and initializer lists in attribute arguments. Because
expression parameter pack expansion requires additional handling while
creating and instantiating templates, the support for them must be
explicitly supported through the AcceptsExprPack flag.
Handling expression pack expansions may require a delay to when the
arguments of an attribute are correctly populated. To this end,
attributes that are set to accept these - through setting the
AcceptsExprPack flag - will automatically have an additional variadic
expression argument member named DelayedArgs. This member is not
exposed the same way other arguments are but is set through the new
CreateWithDelayedArgs creator function generated for applicable
attributes.
To illustrate how to implement support for expression pack expansion
support, clang::annotate is made to support pack expansions. This is
done by making handleAnnotationAttr delay setting the actual attribute
arguments until after template instantiation if it was unable to
populate the arguments due to dependencies in the parsed expressions.
Implement P2128R6 in C++23 mode.
Unlike GCC's implementation, this doesn't try to recover when a user
meant to use a comma expression.
Because the syntax changes meaning in C++23, the patch is *NOT*
implemented as an extension. Instead, declaring an array with not
exactly 1 parameter is an error in older languages modes. There is an
off-by-default extension warning in C++23 mode.
Unlike the standard, we supports default arguments;
Ie, we assume, based on conversations in WG21, that the proposed
resolution to CWG2507 will be accepted.
We allow arrays OpenMP sections and C++23 multidimensional array to
coexist:
[a , b] multi dimensional array
[a : b] open mp section
[a, b: c] // error
The rest of the patch is relatively straight forward: we take care to
support an arbitrary number of arguments everywhere.
This patch implements `__builtin_elementwise_add_sat` and `__builtin_elementwise_sub_sat` builtins.
These map to the add/sub saturated math intrinsics described here:
https://llvm.org/docs/LangRef.html#saturation-arithmetic-intrinsics
With this in place we should then be able to replace the x86 SSE adds/subs intrinsics with these generic variants - it looks like other targets should be able to use these as well (arm/aarch64/webassembly all have similar examples in cgbuiltin).
Differential Revision: https://reviews.llvm.org/D117898
See the discussion in https://reviews.llvm.org/D100282. The coroutine
marked always inline might not be inlined properly in current compiler
support. Since the coroutine would be splitted into pieces. And the call
to resume() and destroy() functions might be indirect call. Also the
ramp function wouldn't get inlined under O0 due to pipeline ordering
problems. It might be different to what users expects to. Emit a warning
to tell it.
This is what GCC does too: https://godbolt.org/z/7eajb1Gf8
Reviewed By: Quuxplusone
Differential Revision: https://reviews.llvm.org/D115867
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,
void func();
becomes
void func(void);
This is the third batch of tests being updated (there are a significant
number of other tests left to be updated).
This reverts commit 852afed5e0.
Changes since D114732:
On PS4, we reverse the expectation that classes whose constructor is deleted are not trivially relocatable. Because, at the moment, only classes which are passed in registers are trivially relocatable, and PS4 allows passing in registers if the copy constructor is deleted, the original assertions were broken on PS4.
(This is kinda similar to DR1734.)
Reviewed By: gribozavr2
Differential Revision: https://reviews.llvm.org/D119017
This change enables library code to skip paired move-construction and destruction for `trivial_abi` types, as if they were trivially-movable and trivially-destructible. This offers an extension to the performance fix offered by `trivial_abi`: rather than only offering trivial-type-like performance for pass-by-value, it also offers it for library code that moves values but not as arguments.
For example, if we use `memcpy` for trivially relocatable types inside of vector reallocation, and mark `unique_ptr` as `trivial_abi` (via `_LIBCPP_ABI_ENABLE_UNIQUE_PTR_TRIVIAL_ABI` / `_LIBCPP_ABI_UNSTABLE` / etc.), this would speed up `vector<unique_ptr>::push_back` by 40% on my benchmarks. (Though note that in this case, the compiler could have done this anyway, but happens not to due to the inlining horizon.)
If accepted, I intend to follow up with exactly such changes to library code, including and especially `std::vector`, making them use a trivial relocation operation on trivially relocatable types.
**D50119 and P1144:**
This change is very similar to D50119, which was rejected from Clang. (That change was an implementation of P1144, which is not yet part of the C++ standard.)
The intent of this change, rather than trying to pick a winning proposal for trivial relocation operations, is to extend the behavior of `trivial_abi` in a way that could be made compatible with any such proposal. If P1144 or any similar proposal were accepted, then `trivial_abi`, `__is_trivially_relocatable`, and everything else in this change would be redefined in terms of that.
**Safety:**
It's worth pointing out, specifically, that `trivial_abi` already implies trivial relocatability in a narrow sense: a `trivial_abi` type, when passed by value, has its constructor run in one location, and its destructor run in another, after the type has been trivially relocated (through registers).
Trivial relocatability optimizations could change the number of paired constructor/destructor calls, but this seems unlikely to matter for `trivial_abi` types.
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D114732
Consider the form of the first operand of a class assignment not the
second operand when implicitly starting the lifetimes of union members.
Also add a missing check that the assignment call actually came from a
syntactic assignment, not from a direct call to `operator=`.
Some functions can end up non-externally visible despite not being
declared "static" or in an unnamed namespace in C++ - such as by having
parameters that are of non-external types.
Such functions aren't mistakenly intended to be defining some function
that needs a declaration. They could be maybe more legible (except for
the `operator new` example) with an explicit static, but that's a
stylistic thing outside what should be addressed by a warning.
Part of the _BitInt feature in C2x
(http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2763.pdf) is a new
macro in limits.h named BITINT_MAXWIDTH that can be used to determine
the maximum width of a bit-precise integer type. This macro must expand
to a value that is at least as large as ULLONG_WIDTH.
This adds an implementation-defined macro named __BITINT_MAXWIDTH__ to
specify that value, which is used by limits.h for the standard macro.
This also limits the maximum bit width to 128 bits because backends do
not currently support all mathematical operations (such as division) on
wider types yet. This maximum is expected to be increased in the future.
This matches GCC: https://godbolt.org/z/sM5q95PGY
I realize this is an API break for clang+clang - so I'm totally open to
discussing how we should deal with that. If Apple wants to keep the
Clang layout indefinitely, if we want to put a flag on this so non-Apple
folks can opt out of this fix/new behavior.
Differential Revision: https://reviews.llvm.org/D117616
If this is a SFINAE context, then continuing to look up names
(in particular, to treat a non-function as a function, and then
do ADL) might too-eagerly complete a type that it's not safe to
complete right now. We should just say "okay, that's a substitution
failure" and not do any more work than absolutely required.
Fixes#52970.
Differential Revision: https://reviews.llvm.org/D117603
This commit checks if a function is marked with the naked attribute
and, if it is, will silence the emission of any unused-parameter
warning.
Inside a naked function only the usage of basic ASM instructions is
expected. In this context the parameters can actually be used by
fetching them according to the underlying ABI. Since parameters might
be used through ASM instructions, the linter and the compiler will have
a hard time understanding if one of those is unused or not, therefore
no unused-parameter warning should ever be triggered whenever a
function is marked naked.
This patch emits an error on AIX and z/OS because XCOFF and GOFF does not currently implement builtin function `CFStringMakeConstantString`. Tests that use this builtin were also disabled.
Reviewed By: SeanP
Differential Revision: https://reviews.llvm.org/D117315
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
Now when we are checking if the expression `co_await
promise.final_suspend()` is not throw, we would check unconditionally
for its child expressions recursively. It takes unnecessary time. And
the compiler would complains if the implementation in final_suspend()
may throw even if the higher level function signature marked noexcept
already.
This fixes bug48453 too.
Often we run into situations where we want to ignore
warnings from system headers, but Clang will still
give warnings about the contents of a macro defined
in a system header used in user-code.
Introduce a ShowInSystemMacro option to be able to
specify which warnings we do want to keep raising
warnings for. The current behavior is kept in this patch
(i.e. warnings from system macros are enabled by default).
The decision as to whether this should be an opt-in or opt-out
feature can be made in a separate patch.
To put the feature to test, replace duplicated code for
Wshadow and Wold-style-cast with the SuppressInSystemMacro tag.
Also disable the warning for C++20 designators, fixing #52944.
Differential Revision: https://reviews.llvm.org/D116833
Prior to this patch, clang might suggest a deprecated name of a declaration over another name as the only mechanism for resolving two typo corrections referring to the same underlying declaration has previously been an alphabetical sort.
This patch adjusts this resolve by also taking into account whether one of two declarations are deprecated. If the new one is deprecated it may not replace a previous correction with a non-deprecated correction and a previous deprecated correction always gets replaced by a non-deprecated new correction.
Fixes https://github.com/llvm/llvm-project/issues/47272
Differential Revision: https://reviews.llvm.org/D116775
The compiler would crash if we lookup for name in transparent decl
context. See the tests attached for example.
I think this should make sense since the member declared in transparent
DeclContext are semantically defined in the enclosing (non-transparent)
DeclContext, this is the definition for transparent DeclContext.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D116792
This mimics the style of 90010c2e1 (Don't consider 'LinkageSpec' when
calculating DeclContext 'Encloses'). Since ExportDecl and LinkageSpec
are transparent DeclContext, they share some similarity.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D116911
This allows the body to be parsed.
An special-case that would replace a missing if condition with OpaqueValueExpr
was removed as it's now redundant (unless recovery-expr is disabled).
For loops are not handled at this point, as the parsing is more complicated.
Differential Revision: https://reviews.llvm.org/D113752
Make clang-cl error when a function definition is missing 'noexcept',
and succeed without warnings when missing '__declspec(nothrow)' or 'throw'.
Fixes pr52860
Differential Revision: https://reviews.llvm.org/D116256
This change fixes a compiler crash that was introduced in https://reviews.llvm.org/D103611: `Sema::BuildVAArgExpr` attempted to retrieve a corresponding signed type for `bool` by calling `ASTContext::getCorrespondingSignedType`.
rdar://86580370
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D116272
This is that diff I was aiming for. When transitioning code from
coroutines-ts to c++20, it can be useful to add a using declaration to
std::experimental pointing to std::coroutine_traits. This permits
that use by checking whether lookup in std::experimentl finds a
different decl to lookup in std. You still get a warning about
std::experimental::coroutine_traits being a thing, just not an error.
Reviewed By: ChuanqiXu
Differential Revision: https://reviews.llvm.org/D115943
First, let's check we get a TemplateDecl, before complaining about
where it might have been found.
Second, if it came from an unexpected place, show where that location is.
Reviewed By: ChuanqiXu
Differential Revision: https://reviews.llvm.org/D116164
This reverts commit 6d09aaecdf.
The test uses ulimit and ran into problems on some bots. Run on linux only.
There's nothing platform-specific about the code we're testing, so this
should be enough to ensure correctness.
According to [dcl.fct.def.coroutine]p6, the promise_type is allowed to
not define return_void nor return_value:
> If searches for the names return_void and return_value in the scope
> of the promise type each find any declarations, the program is
> ill-formed.
> [Note 1: If return_void is found, flowing off the end of a coroutine is
> equivalent to a co_return with no operand. Otherwise, flowing off the
> end of a coroutine results in
> undefined behavior ([stmt.return.coroutine]). — end note]
So the program isn't ill-formed if the promise_type doesn't define
return_void nor return_value. It is just a potential UB. So the program
should be allowed to compile.
Reviewed By: urnathan
Differential Revision: https://reviews.llvm.org/D116204
Control-Flow Integrity (CFI) replaces references to address-taken
functions with pointers to the CFI jump table. This is a problem
for low-level code, such as operating system kernels, which may
need the address of an actual function body without the jump table
indirection.
This change adds the __builtin_function_start() builtin, which
accepts an argument that can be constant-evaluated to a function,
and returns the address of the function body.
Link: https://github.com/ClangBuiltLinux/linux/issues/1353
Depends on D108478
Reviewed By: pcc, rjmccall
Differential Revision: https://reviews.llvm.org/D108479
The diagnostics concerning mixing std::experimental and std are
somewhat wordy and have some typographical errors. Diagnostics do not
start with a capital letter nor end with a fullstop. Usually we try
and link clauses with a semicolon, rather than start a new sentence.
So that's what this patch does. Along with avoiding repetition about
std::experimental going away.
Differential Revision: https://reviews.llvm.org/D116026
As requested in the review, this implements unary +,-,~, and ! for
vector types.
All of our boolean operations on vector types should be using something
like vcmpeqd, which results in a mask of '-1' for the 'truth' type. We are
currently instead using '1', which results in some incorrect
calculations when used later (note that it does NOT result in a boolean
vector, as that is not really a thing).
This patch corrects that 1 to be a -1, and updates the affected tests.
Differential Revision: https://reviews.llvm.org/D115670
Arthur O'Dwyer