Rewording "static_assert" diagnostics

This patch rewords the static assert diagnostic output. Failing a
_Static_assert in C should not report that static_assert failed. This
changes the wording to b

Rewording "static_assert" diagnostics

This patch rewords the static assert diagnostic output. Failing a
_Static_assert in C should not report that static_assert failed. This
changes the wording to be more like GCC and uses "static assertion"
when possible instead of hard coding the name. This also changes some
instances of 'static_assert' to instead be based on the token in the
source code.

Differential Revision: https://reviews.llvm.org/D129048

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Revert "Rewording the "static_assert" to static assertion"

Looks like we again are going to have problems with libcxx tests that
are overly specific in their dependency on clang's diagnostics.

This

Revert "Rewording the "static_assert" to static assertion"

Looks like we again are going to have problems with libcxx tests that
are overly specific in their dependency on clang's diagnostics.

This reverts commit 6542cb55a3eb115b1c3592514590a19987ffc498.

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Rewording the "static_assert" to static assertion

This patch is basically the rewording of the static assert statement's
output(error) on screen after failing. Failing a _Static_assert in C
should n

Rewording the "static_assert" to static assertion

This patch is basically the rewording of the static assert statement's
output(error) on screen after failing. Failing a _Static_assert in C
should not report that static_assert failed. It’d probably be better to
reword the diagnostic to be more like GCC and say “static assertion”
failed in both C and C++.

consider a c file having code

_Static_assert(0, "oh no!");

In clang the output is like:

<source>:1:1: error: static_assert failed: oh no!
_Static_assert(0, "oh no!");
^ ~
1 error generated.
Compiler returned: 1

Thus here the "static_assert" is not much good, it will be better to
reword it to the "static assertion failed" to more generic. as the gcc
prints as:

<source>:1:1: error: static assertion failed: "oh no!"
1 | _Static_assert(0, "oh no!");
| ^~~~~~~~~~~~~~
Compiler returned: 1

The above can also be seen here. This patch is about rewording
the static_assert to static assertion.

Differential Revision: https://reviews.llvm.org/D129048

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Revert "Rewording "static_assert" diagnostics"

This reverts commit b7e77ff25fb2412f6ab6d6cc756666b0e2f97bd3.

Reason: Broke sanitizer builds bots + libcxx. 'static assertion
expression is not an int

Revert "Rewording "static_assert" diagnostics"

This reverts commit b7e77ff25fb2412f6ab6d6cc756666b0e2f97bd3.

Reason: Broke sanitizer builds bots + libcxx. 'static assertion
expression is not an integral constant expression'. More details
available in the Phabricator review: https://reviews.llvm.org/D129048

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Rewording "static_assert" diagnostics

This patch rewords the static assert diagnostic output. Failing a
_Static_assert in C should not report that static_assert failed. This
changes the wording to b

Rewording "static_assert" diagnostics

This patch rewords the static assert diagnostic output. Failing a
_Static_assert in C should not report that static_assert failed. This
changes the wording to be more like GCC and uses "static assertion"
when possible instead of hard coding the name. This also changes some
instances of 'static_assert' to instead be based on the token in the
source code.

Differential Revision: https://reviews.llvm.org/D129048

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Properly track whether a variable is constant-initialized.

This fixes miscomputation of __builtin_constant_evaluated in the
initializer of a variable that's not usable in constant expressions, but
i

Properly track whether a variable is constant-initialized.

This fixes miscomputation of __builtin_constant_evaluated in the
initializer of a variable that's not usable in constant expressions, but
is readable when constant-folding.

If evaluation of a constant initializer fails, we throw away the
evaluated result instead of keeping it as a non-constant-initializer
value for the variable, because it might not be a correct value.
To avoid regressions for initializers that are foldable but not formally
constant initializers, we now try constant-evaluating some globals in
C++ twice: once to check for a constant initializer (in an mode where
is_constannt_evaluated returns true) and again to determine the runtime
value if the initializer is not a constant initializer.

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[Diagnostics] Warn for std::is_constant_evaluated in constexpr mode

Summary:
constexpr int fn1() {
if constexpr (std::is_constant_evaluated()) // condition is always true!
return 0;
else

[Diagnostics] Warn for std::is_constant_evaluated in constexpr mode

Summary:
constexpr int fn1() {
if constexpr (std::is_constant_evaluated()) // condition is always true!
return 0;
else
return 1;
}

constexpr int fn2() {
if (std::is_constant_evaluated())
return 0;
else
return 1;
}

Solves PR42977

Reviewers: rsmith, aaron.ballman

Reviewed By: rsmith

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D69518

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[c++20] Add support for explicit(bool), as described in P0892R2.

Patch by Tyker!

Differential Revision: https://reviews.llvm.org/D60934

llvm-svn: 360311

Revert r359949 "[clang] adding explicit(bool) from c++2a"

This caused Clang to start erroring on the following:

struct S {
  template <typename = int> explicit S();
};

struct T : S {};

Revert r359949 "[clang] adding explicit(bool) from c++2a"

This caused Clang to start erroring on the following:

struct S {
  template <typename = int> explicit S();
};

struct T : S {};

struct U : T {
  U();
};
U::U() {}

$ clang -c /tmp/x.cc
/tmp/x.cc:10:4: error: call to implicitly-deleted default constructor of 'T'
U::U() {}
   ^
/tmp/x.cc:5:12: note: default constructor of 'T' is implicitly deleted
because base class 'S' has no default constructor
struct T : S {};
           ^
1 error generated.

See discussion on the cfe-commits email thread.

This also reverts the follow-ups r359966 and r359968.

> this patch adds support for the explicit bool specifier.
>
> Changes:
> - The parsing for the explicit(bool) specifier was added in ParseDecl.cpp.
> - The storage of the explicit specifier was changed. the explicit specifier was stored as a boolean value in the FunctionDeclBitfields and in the DeclSpec class. now it is stored as a PointerIntPair<Expr*, 2> with a flag and a potential expression in CXXConstructorDecl, CXXDeductionGuideDecl, CXXConversionDecl and in the DeclSpec class.
> - Following the AST change, Serialization, ASTMatchers, ASTComparator and ASTPrinter were adapted.
> - Template instantiation was adapted to instantiate the potential expressions of the explicit(bool) specifier When instantiating their associated declaration.
> - The Add*Candidate functions were adapted, they now take a Boolean indicating if the context allowing explicit constructor or conversion function and this boolean is used to remove invalid overloads that required template instantiation to be detected.
> - Test for Semantic and Serialization were added.
>
> This patch is not yet complete. I still need to check that interaction with CTAD and deduction guides is correct. and add more tests for AST operations. But I wanted first feedback.
> Perhaps this patch should be spited in smaller patches, but making each patch testable as a standalone may be tricky.
>
> Patch by Tyker
>
> Differential Revision: https://reviews.llvm.org/D60934

llvm-svn: 360024

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[clang] adding explicit(bool) from c++2a

this patch adds support for the explicit bool specifier.

Changes:
- The parsing for the explicit(bool) specifier was added in ParseDecl.cpp.
- The storage o

[clang] adding explicit(bool) from c++2a

this patch adds support for the explicit bool specifier.

Changes:
- The parsing for the explicit(bool) specifier was added in ParseDecl.cpp.
- The storage of the explicit specifier was changed. the explicit specifier was stored as a boolean value in the FunctionDeclBitfields and in the DeclSpec class. now it is stored as a PointerIntPair<Expr*, 2> with a flag and a potential expression in CXXConstructorDecl, CXXDeductionGuideDecl, CXXConversionDecl and in the DeclSpec class.
- Following the AST change, Serialization, ASTMatchers, ASTComparator and ASTPrinter were adapted.
- Template instantiation was adapted to instantiate the potential expressions of the explicit(bool) specifier When instantiating their associated declaration.
- The Add*Candidate functions were adapted, they now take a Boolean indicating if the context allowing explicit constructor or conversion function and this boolean is used to remove invalid overloads that required template instantiation to be detected.
- Test for Semantic and Serialization were added.

This patch is not yet complete. I still need to check that interaction with CTAD and deduction guides is correct. and add more tests for AST operations. But I wanted first feedback.
Perhaps this patch should be spited in smaller patches, but making each patch testable as a standalone may be tricky.

Patch by Tyker

Differential Revision: https://reviews.llvm.org/D60934

llvm-svn: 359949

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[Builtins] Implement __builtin_is_constant_evaluated for use in C++2a

Summary:
This patch implements `__builtin_is_constant_evaluated` as specifier by [P0595R2](https://wg21.link/p0595r2). It is bui

[Builtins] Implement __builtin_is_constant_evaluated for use in C++2a

Summary:
This patch implements `__builtin_is_constant_evaluated` as specifier by [P0595R2](https://wg21.link/p0595r2). It is built on the back of Bill Wendling's work for `__builtin_constant_p()`.

More tests to come, but early feedback is appreciated.

I plan to implement warnings for common mis-usages like those belowe in a following patch:
```
void foo(int x) {
if constexpr (std::is_constant_evaluated())) { // condition is always `true`. Should use plain `if` instead.
foo_constexpr(x);
} else {
foo_runtime(x);
}
}
```



Reviewers: rsmith, MaskRay, bruno, void

Reviewed By: rsmith

Subscribers: dexonsmith, zoecarver, fdeazeve, kristina, cfe-commits

Differential Revision: https://reviews.llvm.org/D55500

llvm-svn: 359067

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