`getContext().setMCLineTableRootFile` (from D62074) sets `RootFile.Name` to
`FirstCppHashFilename`. `RootFile.Name` is not processed by -fdebug-prefix-map
and will go to DW_TAG_compile_unit's DT_AT_name and DW_TAG_label's
DW_AT_decl_file. Remap `RootFile.Name`.

Fix another issue reported by https://github.com/llvm/llvm-project/issues/56609

Reviewed By: #debug-info, dblaikie, raj.khem

Differential Revision: https://reviews.llvm.org/D131848

This patch deprecates Optional::map in favor of Optional::transform
for consistency with std::optional::transform in C++23.

Note that I've migrated all known users of Optional::map.

Differential Revision: https://reviews.llvm.org/D131842

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D131442

Implements [variant.relops] and [variant.monostate.relops] for P1614R2

Reviewed By: Mordante, #libc, avogelsgesang

Differential Revision: https://reviews.llvm.org/D131372

After 9144e493 this performs the same
transform inside the other ifdef.

[c++] implements DR692, DR1395 and tentatively DR1432, about partial ordering of variadic template partial specialization or function template

DR692 handles two cases: pack expansion (for class/var template) and function parameter pack. The former needs DR1432 as a fix, and the latter needs DR1395 as a fix. However, DR1432 has not yet made a wording change. so I made a tentative fix for DR1432 with the same spirit as DR1395.

Reviewed By: aaron.ballman, erichkeane, #clang-language-wg

Differential Revision: https://reviews.llvm.org/D128745

This fixes https://github.com/llvm/llvm-project/issues/56050.

Plus some readability changes.

DiagnoseNullConversion is needlessly calling isNullPointerConstant which
is an expensive routine due to its calls to a constant evaluator --
which we don't need.

Building the Linux Kernel (x86_64) with this fix has improved build
times by ~2.1%. This is mainly due to the following methods no longer
needing to be called anywhere near as often:
1) ExprConstant::CheckICE (reduced CPU cycles by ~90%)
2) IntExprEvaluator::VisitBinaryOperator (reduced CPU cycles by ~50%)

Reviewed By: rtrieu, nickdesaulniers

Differential Revision: https://reviews.llvm.org/D131532

These vectors are fully initialized so the placeholder value is irrelevant

This reverts commit bc60cf23.
Doesn't build on Windows and breaks gcc 9 build, see
https://reviews.llvm.org/D116203#3722094 and
https://reviews.llvm.org/D116203#3722128

Also revert two follow-ups. One fixed a warning added in
bc60cf23, the other
makes use of the feature added in bc60cf23
in libc++:

Revert "[libcxx][NFC] utilises compiler builtins for unary transform type-traits"
This reverts commit 06a1d917.

Revert "[Sema] Fix a warning"
This reverts commit c85abbe8.

Identified with readability-redundant-string-init.

Identified with readability-redundant-member-init.

Identified with readability-qualified-auto.

Identified with readability-const-return-type.

This should fix failures on some bots due to 1cf81274
(e.g. https://lab.llvm.org/buildbot#builders/196/builds/16684)

This patch fixes:

  clang/lib/Sema/SemaType.cpp:9469:3: error: default label in switch
  which covers all enumeration values
  [-Werror,-Wcovered-switch-default]

Use has_value()/value() instead of hasValue()/getValue()

Add a fix to check that FDE pc-begin targets are defined before calling
getBlock (which will crash if the target is not defined). FDE pc-begins
pointing at undefined symbols are expected to arise only in obscure
circumstances (malformed objects, or removal of targets by JITLink
passes), but we want to handle them gracefully. With this patch the
FDE will be retained, but without any keepalive edge to it. Unless
some pass takes action to mark it as live it will be dead-stripped.

To make it easier for passes to connect FDEs to their targets a new
EHFrameCFIBlockInspector utility is added. This allows clients to
quickly determine whether a CFI record is a CIE or an FDE (assuming
that it's valid), and retrieve any personality, pc-begin, cie, or
LSDA edges associated with it.

Depends on D116203

Reviewed By: #libc, philnik

Differential Revision: https://reviews.llvm.org/D131732

Adds

* `__add_lvalue_reference`
* `__add_pointer`
* `__add_rvalue_reference`
* `__decay`
* `__make_signed`
* `__make_unsigned`
* `__remove_all_extents`
* `__remove_extent`
* `__remove_const`
* `__remove_volatile`
* `__remove_cv`
* `__remove_pointer`
* `__remove_reference`
* `__remove_cvref`

These are all compiler built-in equivalents of the unary type traits
found in [[meta.trans]][1]. The compiler already has all of the
information it needs to answer these transformations, so we can skip
needing to make partial specialisations in standard library
implementations (we already do this for a lot of the query traits). This
will hopefully improve compile times, as we won't need use as much
memory in such a base part of the standard library.

[1]: http://wg21.link/meta.trans

Co-authored-by: zoecarver

Reviewed By: aaron.ballman, rsmith

Differential Revision: https://reviews.llvm.org/D116203

Test cases for selecting the index with the minimum value.

Noticed while investigating the regressions in D106675

Reviewed By: philnik

Differential Revision: https://reviews.llvm.org/D131854

These are guaranteed not to create undef/poison if the shift amount is known to be in range

Enabling freeze(shl()) -> shl(freeze()) was affecting this test

These are guaranteed not to create undef/poison

Implements part of:
- P1614R2 The Mothership has Landed

Reviewed By: avogelsgesang, #libc, philnik

Differential Revision: https://reviews.llvm.org/D131421

Increasing the constexpr evaluation limit breaks this clang-tidy test
for GCC. As discussed in D131317 disable the test in GCC.

Reviewed By: philnik, #libc

Differential Revision: https://reviews.llvm.org/D131835

Mingw headers are all lowercase, and can be used for cross compilation
from case sensitive file systems.

The official Windows SDK headers aren't self-consistent wrt upper/lower
case, so those headers can't be used on case sensitive systems without
a layer providing case insensitivity anyway.

This matches other includes of windows.h throughout the codebase.