Revert "Switch builtin strings to use string tables" (#119638)

Reverts llvm/llvm-project#118734

There are currently some specific versions of MSVC that are miscompiling
this code (we think). We

Revert "Switch builtin strings to use string tables" (#119638)

Reverts llvm/llvm-project#118734

There are currently some specific versions of MSVC that are miscompiling
this code (we think). We don't know why as all the other build bots and
at least some folks' local Windows builds work fine.

This is a candidate revert to help the relevant folks catch their
builders up and have time to debug the issue. However, the expectation
is to roll forward at some point with a workaround if at all possible.

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Switch builtin strings to use string tables (#118734)

The Clang binary (and any binary linking Clang as a library), when built
using PIE, ends up with a pretty shocking number of dynamic relocation

Switch builtin strings to use string tables (#118734)

The Clang binary (and any binary linking Clang as a library), when built
using PIE, ends up with a pretty shocking number of dynamic relocations
to apply to the executable image: roughly 400k.

Each of these takes up binary space in the executable, and perhaps most
interestingly takes start-up time to apply the relocations.

The largest pattern I identified were the strings used to describe
target builtins. The addresses of these string literals were stored into
huge arrays, each one requiring a dynamic relocation. The way to avoid
this is to design the target builtins to use a single large table of
strings and offsets within the table for the individual strings. This
switches the builtin management to such a scheme.

This saves over 100k dynamic relocations by my measurement, an over 25%
reduction. Just looking at byte size improvements, using the `bloaty`
tool to compare a newly built `clang` binary to an old one:

```
FILE SIZE VM SIZE
-------------- --------------
+1.4% +653Ki +1.4% +653Ki .rodata
+0.0% +960 +0.0% +960 .text
+0.0% +197 +0.0% +197 .dynstr
+0.0% +184 +0.0% +184 .eh_frame
+0.0% +96 +0.0% +96 .dynsym
+0.0% +40 +0.0% +40 .eh_frame_hdr
+114% +32 [ = ] 0 [Unmapped]
+0.0% +20 +0.0% +20 .gnu.hash
+0.0% +8 +0.0% +8 .gnu.version
+0.9% +7 +0.9% +7 [LOAD #2 [R]]
[ = ] 0 -75.4% -3.00Ki .relro_padding
-16.1% -802Ki -16.1% -802Ki .data.rel.ro
-27.3% -2.52Mi -27.3% -2.52Mi .rela.dyn
-1.6% -2.66Mi -1.6% -2.66Mi TOTAL
```

We get a 16% reduction in the `.data.rel.ro` section, and nearly 30%
reduction in `.rela.dyn` where those reloctaions are stored.

This is also visible in my benchmarking of binary start-up overhead at
least:

```
Benchmark 1: ./old_clang --version
Time (mean ± σ): 17.6 ms ± 1.5 ms [User: 4.1 ms, System: 13.3 ms]
Range (min … max): 14.2 ms … 22.8 ms 162 runs

Benchmark 2: ./new_clang --version
Time (mean ± σ): 15.5 ms ± 1.4 ms [User: 3.6 ms, System: 11.8 ms]
Range (min … max): 12.4 ms … 20.3 ms 216 runs

Summary
'./new_clang --version' ran
1.13 ± 0.14 times faster than './old_clang --version'
```

We get about 2ms faster `--version` runs. While there is a lot of noise
in binary execution time, this delta is pretty consistent, and
represents over 10% improvement. This is particularly interesting to me
because for very short source files, repeatedly starting the `clang`
binary is actually the dominant cost. For example, `configure` scripts
running against the `clang` compiler are slow in large part because of
binary start up time, not the time to process the actual inputs to the
compiler.

----

This PR implements the string tables using `constexpr` code and the
existing macro system. I understand that the builtins are moving towards
a TableGen model, and if complete that would provide more options for
modeling this. Unfortunately, that migration isn't complete, and even
the parts that are migrated still rely on the ability to break out of
the TableGen model and directly expand an X-macro style `BUILTIN(...)`
textually. I looked at trying to complete the move to TableGen, but it
would both require the difficult migration of the remaining targets, and
solving some tricky problems with how to move away from any macro-based
expansion.

I was also able to find a reasonably clean and effective way of doing
this with the existing macros and some `constexpr` code that I think is
clean enough to be a pretty good intermediate state, and maybe give a
good target for the eventual TableGen solution. I was also able to
factor the macros into set of consistent patterns that avoids a
significant regression in overall boilerplate.

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[clang] Don't define predefined macros multiple times

Fix several instances of macros being defined multiple times
in several targets. Most of these are just simple duplication in a
TargetInfo or OS

[clang] Don't define predefined macros multiple times

Fix several instances of macros being defined multiple times
in several targets. Most of these are just simple duplication in a
TargetInfo or OSTargetInfo of things already defined in
InitializePredefinedMacros or InitializeStandardPredefinedMacros,
but there are a few that aren't:
* AArch64 defines a couple of feature macros for armv8.1a that are
handled generically by getTargetDefines.
* CSKY needs to take care when CPUName and ArchName are the same.
* Many os/target combinations result in __ELF__ being defined twice.
Instead define __ELF__ just once in InitPreprocessor based on
the Triple, which already knows what the object format is based
on os and target.

These changes shouldn't change the final result of which macros are
defined, with the exception of the changes to __ELF__ where if you
explicitly specify the object type in the triple then this affects
if __ELF__ is defined, e.g. --target=i686-windows-elf results in it
being defined where it wasn't before, but this is more accurate as an
ELF file is in fact generated.

Differential Revision: https://reviews.llvm.org/D150966

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[clang] Optimize clang::Builtin::Info density

Reorganize clang::Builtin::Info to have them naturally align on 4 bytes
boundaries.

Instead of storing builtin headers as a straight char pointer, enum

[clang] Optimize clang::Builtin::Info density

Reorganize clang::Builtin::Info to have them naturally align on 4 bytes
boundaries.

Instead of storing builtin headers as a straight char pointer, enumerate
them and store the enum. It allows to use a small enum instead of a
pointer to reference them.

On a 64 bit machine, this brings sizeof(clang::Builtin::Info) from 56
down to 48 bytes.

On a release build on my Linux 64 bit machine, it shrinks the size of
libclang-cpp.so by 193kB.

The impact on performance is negligible in terms of instruction count,
but the wall time seems better, see
https://llvm-compile-time-tracker.com/compare.php?from=b3d8639f3536a4876b511aca9fb7948ff9266cee&to=a89b56423f98b550260a58c41e64aff9e56b76be&stat=task-clock

Differential Revision: https://reviews.llvm.org/D142024

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Move from llvm::makeArrayRef to ArrayRef deduction guides - clang/ part

This is a follow-up to https://reviews.llvm.org/D140896, split into
several parts as it touches a lot of files.

Differential

Move from llvm::makeArrayRef to ArrayRef deduction guides - clang/ part

This is a follow-up to https://reviews.llvm.org/D140896, split into
several parts as it touches a lot of files.

Differential Revision: https://reviews.llvm.org/D141139

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[Hexagon][VE][WebAssembly] Define __GCC_HAVE_SYNC_COMPARE_AND_SWAP macros

Define __GCC_HAVE_SYNC_COMPARE_AND_SWAP macros

Reviewed By: kparzysz, aheejin, MaskRay

Differential Revision: https://revi

[Hexagon][VE][WebAssembly] Define __GCC_HAVE_SYNC_COMPARE_AND_SWAP macros

Define __GCC_HAVE_SYNC_COMPARE_AND_SWAP macros

Reviewed By: kparzysz, aheejin, MaskRay

Differential Revision: https://reviews.llvm.org/D140757

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[clang] Use a StringRef instead of a raw char pointer to store builtin and call information

This avoids recomputing string length that is already known at compile time.

It has a slight impact on pr

[clang] Use a StringRef instead of a raw char pointer to store builtin and call information

This avoids recomputing string length that is already known at compile time.

It has a slight impact on preprocessing / compile time, see

https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u

This a recommit of e953ae5bbc313fd0cc980ce021d487e5b5199ea4 and the subsequent fixes caa713559bd38f337d7d35de35686775e8fb5175 and 06b90e2e9c991e211fecc97948e533320a825470.

The above patchset caused some version of GCC to take eons to compile clang/lib/Basic/Targets/AArch64.cpp, as spotted in aa171833ab0017d9732e82b8682c9848ab25ff9e.
The fix is to make BuiltinInfo tables a compilation unit static variable, instead of a private static variable.

Differential Revision: https://reviews.llvm.org/D139881

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[Clang][VE] Add vector load intrinsics

Add vector load intrinsic instructions for VE.

Reviewed By: simoll

Differential Revision: https://reviews.llvm.org/D121049

[VE] Clang toolchain for VE

Summary:
This patch enables compilation of C code for the VE target with Clang.

Differential Revision: https://reviews.llvm.org/D79411