Reapply "[RISCV] Support RISCV Atomics ABI attributes (#84597)"

This patch adds support for the atomic_abi attribute, specifid in
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/ris

Reapply "[RISCV] Support RISCV Atomics ABI attributes (#84597)"

This patch adds support for the atomic_abi attribute, specifid in
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc#tag_riscv_atomic_abi-14-uleb128version.

This was previously reverted due to ld.bfd segfaulting w/ unknown riscv
attributes. Attribute emission is now guarded by a backend flag
`--riscv-abi-attributes`, which is off by default. Linker support in
LLD for attribute merging is now in a standalone patch.

Reviewers: kito-cheng, MaskRay, asb

Reviewed By: MaskRay

Pull Request: https://github.com/llvm/llvm-project/pull/90266

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Revert "[RISCV] Support RISCV Atomics ABI attributes (#84597)"

This reverts commit 9221f3af8f832d990be986c05d964ad37e5a2356.

As reported
<https://github.com/llvm/llvm-project/pull/84597#issuecommen

Revert "[RISCV] Support RISCV Atomics ABI attributes (#84597)"

This reverts commit 9221f3af8f832d990be986c05d964ad37e5a2356.

As reported
<https://github.com/llvm/llvm-project/pull/84597#issuecomment-2079128332>
and confirmed by me locally, adding these attributes causes current GNU
ld to segfault when processing the input. Reverted so we can discuss
the best next step.

show more ...

[RISCV] Support RISCV Atomics ABI attributes (#84597)

This patch adds support for the `atomic_abi` attribute, specifid in

https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-el

[RISCV] Support RISCV Atomics ABI attributes (#84597)

This patch adds support for the `atomic_abi` attribute, specifid in

https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc#tag_riscv_atomic_abi-14-uleb128version.

The atomics_abi tag merging is conducted as follows:

- UNKNOWN is safe to merge with all other values.
- A6C is compatible with A6S, and results in the A6C ABI.
- A6C is incompatible with A7, and results in an error.
- A6S and A7 are compatible, and merging results in the A7 ABI.

Note: the A7 is not yet supported in either LLVM or in any current
hardware,
and is therefore ommited from attribute generation in
RISCVTargetStreamer.

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Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer

We can build it with -Werror=global-constructors now. This helps
in situation where libSuppor

Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer

We can build it with -Werror=global-constructors now. This helps
in situation where libSupport is embedded as a shared library,
potential with dlopen/dlclose scenario, and when command-line
parsing or other facilities may not be involved. Avoiding the
implicit construction of these cl::opt can avoid double-registration
issues and other kind of behavior.

Reviewed By: lattner, jpienaar

Differential Revision: https://reviews.llvm.org/D105959

show more ...

Revert "Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer"

This reverts commit af9321739b20becf170e6bb5060b8d780e1dc8dd.
Still some specific co

Revert "Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer"

This reverts commit af9321739b20becf170e6bb5060b8d780e1dc8dd.
Still some specific config broken in some way that requires more
investigation.

show more ...

Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer

We can build it with -Werror=global-constructors now. This helps
in situation where libSuppor

Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer

We can build it with -Werror=global-constructors now. This helps
in situation where libSupport is embedded as a shared library,
potential with dlopen/dlclose scenario, and when command-line
parsing or other facilities may not be involved. Avoiding the
implicit construction of these cl::opt can avoid double-registration
issues and other kind of behavior.

Reviewed By: lattner, jpienaar

Differential Revision: https://reviews.llvm.org/D105959

show more ...

Revert "Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer"

This reverts commit 42f588f39c5ce6f521e3709b8871d1fdd076292f.
Broke some buildbots

Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer

We can build it with -Werror=global-constructors now. This helps
in situation where libSuppor

Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer

We can build it with -Werror=global-constructors now. This helps
in situation where libSupport is embedded as a shared library,
potential with dlopen/dlclose scenario, and when command-line
parsing or other facilities may not be involved. Avoiding the
implicit construction of these cl::opt can avoid double-registration
issues and other kind of behavior.

Reviewed By: lattner, jpienaar

Differential Revision: https://reviews.llvm.org/D105959

show more ...

[RISCV] ELF attribute section for RISC-V.

Leverage ARM ELF build attribute section to create ELF attribute section
for RISC-V. Extract the common part of parsing logic for this section
into ELFAttri

[RISCV] ELF attribute section for RISC-V.

Leverage ARM ELF build attribute section to create ELF attribute section
for RISC-V. Extract the common part of parsing logic for this section
into ELFAttributeParser.[cpp|h] and ELFAttributes.[cpp|h].

Differential Revision: https://reviews.llvm.org/D74023

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