Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#108039)

The PR reapply https://github.com/llvm/llvm-projec

Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#108039)

The PR reapply https://github.com/llvm/llvm-project/pull/97308.

- Implement [CWG1815](https://wg21.link/CWG1815): Support lifetime
extension of temporary created by aggregate initialization using a
default member initializer.

- Fix crash that introduced in
https://github.com/llvm/llvm-project/pull/97308. In
`InitListChecker::FillInEmptyInitForField`, when we enter
rebuild-default-init context, we copy all the contents of the parent
context to the current context, which will cause the `MaybeODRUseExprs`
to be lost. But we don't need to copy the entire context, only the
`DelayedDefaultInitializationContext` was required, which is used to
build `SourceLocExpr`, etc.

---------

Signed-off-by: yronglin <yronglin777@gmail.com>

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Revert "Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#97308)"

This reverts commit 45c8766973bb3bb73dd8d9

Revert "Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#97308)"

This reverts commit 45c8766973bb3bb73dd8d996231e114dcf45df9f
and 049512e39d96995cb373a76cf2d009a86eaf3aab.

This change triggers failed asserts on inputs like this:

struct a {
} constexpr b;
class c {
public:
c(a);
};
class B {
public:
using d = int;
struct e {
enum { f } g;
int h;
c i;
d j{};
};
};
B::e k{B::e::f, int(), b};

Compiled like this:

clang -target x86_64-linux-gnu -c repro.cpp
clang: ../../clang/lib/CodeGen/CGExpr.cpp:3105: clang::CodeGen::LValue
clang::CodeGen::CodeGenFunction::EmitDeclRefLValue(const clang::DeclRefExpr*):
Assertion `(ND->isUsed(false) || !isa<VarDecl>(ND) || E->isNonOdrUse() ||
!E->getLocation().isValid()) && "Should not use decl without marking it used!"' failed.

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Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#97308)

The PR reapply https://github.com/llvm/llvm-project

Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#97308)

The PR reapply https://github.com/llvm/llvm-project/pull/92527.
Implemented CWG1815 and fixed the bugs mentioned in the comments of
https://github.com/llvm/llvm-project/pull/92527 and
https://github.com/llvm/llvm-project/pull/87933.

The reason why the original PR was reverted was that errors might occur
during the rebuild.

---------

Signed-off-by: yronglin <yronglin777@gmail.com>

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[Clang][ExprConstant] fix constant expression did not evaluate to integer (#97146)

fixes https://github.com/llvm/llvm-project/issues/96670

The cause is that we might return a lvalue here at

[Clang][ExprConstant] fix constant expression did not evaluate to integer (#97146)

fixes https://github.com/llvm/llvm-project/issues/96670

The cause is that we might return a lvalue here at


https://github.com/llvm/llvm-project/blob/3e53c97d33210db68188e731e93ee48dbaeeae32/clang/lib/AST/ExprConstant.cpp#L15861-L15865

This PR will make sure we return a rvalue in `FastEvaluateAsRValue`.

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Revert "Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#92527)" (#94600)

Reverting due to
https://github.

Revert "Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#92527)" (#94600)

Reverting due to
https://github.com/llvm/llvm-project/pull/92527#issuecomment-2149120420.

This reverts commit f049d72ac2bcc40fd91d4e95148658021fb24bf1.

Co-authored-by: Bogdan Graur <bgraur@google.com>

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Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#92527)

This PR reapply https://github.com/llvm/llvm-projec

Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#92527)

This PR reapply https://github.com/llvm/llvm-project/pull/87933

Signed-off-by: yronglin <yronglin777@gmail.com>

show more ...

Revert "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer (#87933)"

This reverts commit 17daa204feadf9c28fc13b7daa69c3cb

Revert "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer (#87933)"

This reverts commit 17daa204feadf9c28fc13b7daa69c3cbe865b238.

Multiple examples on the PR
https://github.com/llvm/llvm-project/pull/87933

show regressions, so reverting until they can be fixed in the followup.

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[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer (#87933)

This PR complete [DR1815](https://wg21.link/CWG1815) under th

[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer (#87933)

This PR complete [DR1815](https://wg21.link/CWG1815) under the guidance
of `FIXME` comments. And reuse `CXXDefaultInitExpr` rewrite machinery to
clone the initializer expression on each use that would lifetime extend
its temporaries.

---------

Signed-off-by: yronglin <yronglin777@gmail.com>

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[clang] Reword apologetic Clang diagnostic messages (#76310)

Fixes Issue: https://github.com/llvm/llvm-project/issues/61256

[clang][ExprConst] Fix crash on uninitialized array subobject (#67817)

https://reviews.llvm.org/D146358 was assuming that all subobjects have
their own name (`SubobjectDecl`), but it was not true f

[clang][ExprConst] Fix crash on uninitialized array subobject (#67817)

https://reviews.llvm.org/D146358 was assuming that all subobjects have
their own name (`SubobjectDecl`), but it was not true for array
elements.

Fixes https://github.com/llvm/llvm-project/issues/67317

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[c++20] Implement semantic restrictions for C++20 designated
initializers.

This has some interesting interactions with our existing extensions to
support C99 designated initializers as an extension

[c++20] Implement semantic restrictions for C++20 designated
initializers.

This has some interesting interactions with our existing extensions to
support C99 designated initializers as an extension in C++. Those are
resolved as follows:

* We continue to permit the full breadth of C99 designated initializers
in C++, with the exception that we disallow a partial overwrite of an
initializer with a non-trivially-destructible type. (Full overwrite
is OK, because we won't run the first initializer at all.)

* The C99 extensions are disallowed in SFINAE contexts and during
overload resolution, where they could change the meaning of valid
programs.

* C++20 disallows reordering of initializers. We only check for that for
the simple cases that the C++20 rules permit (designators of the form
'.field_name =' and continue to allow reordering in other cases).
It would be nice to improve this behavior in future.

* All C99 designated initializer extensions produce a warning by
default in C++20 mode. People are going to learn the C++ rules based
on what Clang diagnoses, so it's important we diagnose these properly
by default.

* In C++ <= 17, we apply the C++20 rules rather than the C99 rules, and
so still diagnose C99 extensions as described above. We continue to
accept designated C++20-compatible initializers in C++ <= 17 silently
by default (but naturally still reject under -pedantic-errors).

This is not a complete implementation of P0329R4. In particular, that
paper introduces new non-C99-compatible syntax { .field { init } }, and
we do not support that yet.

This is based on a previous patch by Don Hinton, though I've made
substantial changes when addressing the above interactions.

Differential Revision: https://reviews.llvm.org/D59754

llvm-svn: 370544

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Fold -Wreturn-stack-address into general initialization lifetime
checking.

llvm-svn: 337743

Restructure checking for, and warning on, lifetime extension.

This change implements C++ DR1696, which makes initialization of a
reference member of a class from a temporary object ill-formed. The
s

Restructure checking for, and warning on, lifetime extension.

This change implements C++ DR1696, which makes initialization of a
reference member of a class from a temporary object ill-formed. The
standard wording here is imprecise, but we interpret it as meaning that
any time a mem-initializer would result in lifetime extension, the
program is ill-formed.

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

llvm-svn: 337329

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Temporarily revert r337226 "Restructure checking for, and warning on, lifetime extension."

This change breaks on ARM because pointers to clang::InitializedEntity are only
4 byte aligned and do not h

Temporarily revert r337226 "Restructure checking for, and warning on, lifetime extension."

This change breaks on ARM because pointers to clang::InitializedEntity are only
4 byte aligned and do not have 3 bits to store values. A possible solution
would be to change the fields in clang::InitializedEntity to enforce a bigger
alignment requirement.

The error message is

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

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

llvm-svn: 337255

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Restructure checking for, and warning on, lifetime extension.

This change implements C++ DR1696, which makes initialization of a
reference member of a class from a temporary object ill-formed. The
s

Restructure checking for, and warning on, lifetime extension.

This change implements C++ DR1696, which makes initialization of a
reference member of a class from a temporary object ill-formed. The
standard wording here is imprecise, but we interpret it as meaning that
any time a mem-initializer would result in lifetime extension, the
program is ill-formed.

llvm-svn: 337226

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Revert r301742, which caused us to try to evaluate all full-expressions.

Also add testcases for a bunch of expression forms that cause our evaluator to
crash. See PR33140 and PR32864 for crashes tha

Revert r301742, which caused us to try to evaluate all full-expressions.

Also add testcases for a bunch of expression forms that cause our evaluator to
crash. See PR33140 and PR32864 for crashes that this was causing.

This reverts r305287, which reverted r305239, which reverted r301742. The
previous revert claimed that buildbots were broken, but did not add any
testcases and the buildbots have lost all memory of what was wrong here.

Changes to test/OpenMP are not reverted; another change has triggered those
tests to change their output in the same way that r301742 did.

llvm-svn: 306346

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