[clang][DebugInfo] Don't mark structured bindings as artificial (#100355)

This patch is motivated by the debug-info issue in
https://github.com/llvm/llvm-project/issues/48909. Clang is currently
e

[clang][DebugInfo] Don't mark structured bindings as artificial (#100355)

This patch is motivated by the debug-info issue in
https://github.com/llvm/llvm-project/issues/48909. Clang is currently
emitting the `DW_AT_artificial` attribute on debug-info entries for
structured bindings whereas GCC does not. GCC's interpretation of the
DWARF spec is more user-friendly in this regard, so we would like to do
the same in Clang. [`CGDebugInfo` uses `isImplicit` to decide which
variables to mark
artificial](https://github.com/llvm/llvm-project/blob/0c4023ae3b64c54ff51947e9776aee0e963c5635/clang/lib/CodeGen/CGDebugInfo.cpp#L4783-L4784)
(e.g., `ImplicitParamDecls`, compiler-generated variables, etc.). But
for the purposes of debug-info, when we say "artificial", what we really
mean in many cases is: "not explicitly spelled out in source".
`VarDecl`s that back tuple-like bindings are [technically
compiler-generated](https://github.com/llvm/llvm-project/issues/48909#issuecomment-2238976579),
but that is a confusing notion for debug-info, since these bindings
*are* spelled out in source. The [documentation for
`isImplicit`](https://github.com/llvm/llvm-project/blob/68a0d0c76223736351fd7c452bca3ba9d80ca342/clang/include/clang/AST/DeclBase.h#L596-L600)
does to some extent imply that implicit variables aren't written in
source.

This patch adds another condition to deciding whether a `VarDecl` should
be marked artificial. Specifically, don't treat structured bindings as
artificial.

**Main alternatives considered**
1. Don't use `isImplicit` in `CGDebugInfo` when determining whether to
add `DW_AT_artificial`. Instead use some other property of the AST that
would tell us whether a node was explicitly spelled out in source or not
* Considered using `SourceRange` or `SourceLocation` to tell us this,
but didn't find a good way to, e.g., correctly identify that the
implicit `this` parameter wasn't spelled out in source (as opposed to an
unnamed parameter in a function declaration)
2. We could've also added a bit to `VarDeclBitFields` that indicates
that a `VarDecl` is a holding var, but the use-case didn't feel like
good enough justification for this
3. Don't set the `VarDecl` introduced as part of a tuple-like
decomposition as implicit.
* This may affect AST matching/traversal and this specific use-case
wasn't enough to justify such a change

Fixes https://github.com/llvm/llvm-project/issues/48909

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[RemoveDIs] Print IR with debug records by default (#91724)

This patch makes the final major change of the RemoveDIs project, changing the
default IR output from debug intrinsics to debug records.

[RemoveDIs] Print IR with debug records by default (#91724)

This patch makes the final major change of the RemoveDIs project, changing the
default IR output from debug intrinsics to debug records. This is expected to
break a large number of tests: every single one that tests for uses or
declarations of debug intrinsics and does not explicitly disable writing
records.

If this patch has broken your downstream tests (or upstream tests on a
configuration I wasn't able to run):
1. If you need to immediately unblock a build, pass
`--write-experimental-debuginfo=false` to LLVM's option processing for all
failing tests (remember to use `-mllvm` for clang/flang to forward arguments to
LLVM).
2. For most test failures, the changes are trivial and mechanical, enough that
they can be done by script; see the migration guide for a guide on how to do
this: https://llvm.org/docs/RemoveDIsDebugInfo.html#test-updates
3. If any tests fail for reasons other than FileCheck check lines that need
updating, such as assertion failures, that is most likely a real bug with this
patch and should be reported as such.

For more information, see the recent PSA:
https://discourse.llvm.org/t/psa-ir-output-changing-from-debug-intrinsics-to-debug-records/79578

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[Clang][DebugInfo] Clang generates an extra spurious unnamed 'dbg.declare' (#69681)

Do not emit call to llvm.dbg.declare when the variable declaration
is a DecompositionDecl as its instance class i

[Clang][DebugInfo] Clang generates an extra spurious unnamed 'dbg.declare' (#69681)

Do not emit call to llvm.dbg.declare when the variable declaration
is a DecompositionDecl as its instance class is always unnamed.

The emitted debug declare looks like:

call void @llvm.dbg.declare(metadata ..., metadata !xx, metadata ...)
!xx = !DILocalVariable(scope: !..., file: !..., line: ..., type: !...)

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[CodeGenCXX] Convert some tests to opaque pointers (NFC)

Conversion done using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34.

These are tests where the conversion wor

[CodeGenCXX] Convert some tests to opaque pointers (NFC)

Conversion done using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34.

These are tests where the conversion worked out of the box and no
manual fixup was performed.

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[OpaquePtrs][Clang] Add -no-opaque-pointers to tests (NFC)

This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be p

[OpaquePtrs][Clang] Add -no-opaque-pointers to tests (NFC)

This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be part of the migration approach described in
https://discourse.llvm.org/t/enabling-opaque-pointers-by-default/61322/9.

The patch has been produced by replacing %clang_cc1 with
%clang_cc1 -no-opaque-pointers for tests that fail with opaque
pointers enabled. Worth noting that this doesn't cover all tests,
there's a remaining ~40 tests not using %clang_cc1 that will need
a followup change.

Differential Revision: https://reviews.llvm.org/D123115

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[DEBUGINFO] [LLDB] Add support for generating debug-info for structured bindings of structs and arrays

Currently we are not emitting debug-info for all cases of structured bindings a
C++17 feature w

[DEBUGINFO] [LLDB] Add support for generating debug-info for structured bindings of structs and arrays

Currently we are not emitting debug-info for all cases of structured bindings a
C++17 feature which allows us to bind names to subobjects in an initializer.

A structured binding is represented by a DecompositionDecl AST node and the
binding are represented by a BindingDecl. It looks the original implementation
only covered the tuple like case which be represented by a DeclRefExpr which
contains a VarDecl.

If the binding is to a subobject of the struct the binding will contain a
MemberExpr and in the case of arrays it will contain an ArraySubscriptExpr.
This PR adds support emitting debug-info for the MemberExpr and ArraySubscriptExpr
cases as well as llvm and lldb tests for these cases as well as the tuple case.

Differential Revision: https://reviews.llvm.org/D119178

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