[MC] Export MCDXContainerObjectWriter

Similar to other ObjectWriter classes.

MC: Inline createMachObjectWriter into MCAsmBackend

We could do the same to COFF once WinCOFFObjectWriter is cleaned up
(#100303).

ELFObjectWriter: Remove unneeded subclasses

[MC] Remove two unused parameters from MCAsmBackend::fixupNeedsRelaxation

fixupNeedsRelaxation is a simple implementation for
fixupNeedsRelaxationAdvanced. Its users do not utilize MCAsmLayout or
MC

[MC] Remove two unused parameters from MCAsmBackend::fixupNeedsRelaxation

fixupNeedsRelaxation is a simple implementation for
fixupNeedsRelaxationAdvanced. Its users do not utilize MCAsmLayout or
MCRelaxableFragment.

Follow-up to 22c7317f1e954b34a46640db5d509bae1c633348
("[MC] Remove the MCAsmLayout parameter from relocation related functions").

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[MC] Remove the MCAsmLayout parameter from relocation related functions

[RISCV] Support R_RISCV_SET_ULEB128/R_RISCV_SUB_ULEB128 for .uleb128 directives

For a label difference like `.uleb128 A-B`, MC folds A-B even if A and B
are separated by a RISC-V linker-relaxable in

[RISCV] Support R_RISCV_SET_ULEB128/R_RISCV_SUB_ULEB128 for .uleb128 directives

For a label difference like `.uleb128 A-B`, MC folds A-B even if A and B
are separated by a RISC-V linker-relaxable instruction. This incorrect
behavior is currently abused by DWARF v5 .debug_loclists/.debug_rnglists
(DW_LLE_offset_pair/DW_RLE_offset_pair entry kinds) implemented in
Clang/LLVM (see https://github.com/ClangBuiltLinux/linux/issues/1719 for
an instance).

https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/96d6e190e9fc04a8517f9ff7fb9aed3e9876cbd6
defined R_RISCV_SET_ULEB128/R_RISCV_SUB_ULEB128. This patch generates such
a pair of relocations to represent A-B that should not be folded.
GNU assembler computes the directive size by ignoring shrinkable section
content, therefore after linking the value of A-B cannot use more bytes
than the reserved number (`final size of uleb128 value at offset ... exceeds available space`).
We make the same assumption.
```
w1:
call foo
w2:
.space 120
w3:
.uleb128 w2-w1 # 1 byte, 0x08
.uleb128 w3-w1 # 2 bytes, 0x80 0x01
```

We do not conservatively reserve 10 bytes (maximum size of an uleb128
for uint64_t) as that would pessimize DWARF v5
DW_LLE_offset_pair/DW_RLE_offset_pair, nullifying the benefits of
introducing R_RISCV_SET_ULEB128/R_RISCV_SUB_ULEB128 relocations.

The supported expressions are limited. For example,

* non-subtraction `.uleb128 A` is not allowed
* `.uleb128 A-B`: report an error unless A and B are both defined and in the same section

The new cl::opt `-riscv-uleb128-reloc` can be used to suppress the
relocations.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D157657

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Use llvm::endianness::{big,little,native} (NFC)

Note that llvm::support::endianness has been renamed to
llvm::endianness while becoming an enum class as opposed to an
enum. This patch replaces suppo

Use llvm::endianness::{big,little,native} (NFC)

Note that llvm::support::endianness has been renamed to
llvm::endianness while becoming an enum class as opposed to an
enum. This patch replaces support::{big,little,native} with
llvm::endianness::{big,little,native}.

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Use llvm::endianness (NFC)

Now that llvm::support::endianness has been renamed to
llvm::endianness, we can use the shorter form. This patch replaces
support::endianness with llvm::endianness.

[SystemZ/zOS/GOFF] Implement GOFF writer for empty files.

Set ups the infrastructure to create an empty GOFF file.
Also adds a GOFF writer which writes only HDR/END records.

Reviewed By: jhenderson

[SystemZ/zOS/GOFF] Implement GOFF writer for empty files.

Set ups the infrastructure to create an empty GOFF file.
Also adds a GOFF writer which writes only HDR/END records.

Reviewed By: jhenderson, kpn

Differential Revision: https://reviews.llvm.org/D111437

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[MC] Remove FK_Data_6b

D58335 introduced FK_Data_6b for emitting R_RISCV_SET6/R_RISCV_SUB6 in
.eh_frame/.debug_frame.

This is no longer needed after commit
c8ed138c34ddb22610f18468c1b7938f9e2abae5

[MC] Remove FK_Data_6b

D58335 introduced FK_Data_6b for emitting R_RISCV_SET6/R_RISCV_SUB6 in
.eh_frame/.debug_frame.

This is no longer needed after commit
c8ed138c34ddb22610f18468c1b7938f9e2abae5 removed unneeded fixup kinds
for R_RISCV_{SET,ADD,SUB}* and getKindForSizeInBits.

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[RISCV] Make linker-relaxable instructions terminate MCDataFragment

`MCExpr::evaluateAsAbsolute` has a longstanding bug. When the MCAssembler is
non-null and the MCAsmLayout is null, it may incorrec

[RISCV] Make linker-relaxable instructions terminate MCDataFragment

`MCExpr::evaluateAsAbsolute` has a longstanding bug. When the MCAssembler is
non-null and the MCAsmLayout is null, it may incorrectly fold A-B even if A and
B are separated by a linker-relaxable instruction. This behavior can suppress
some ADD/SUB relocations and lead to wrong results if the linker performs
relaxation.

To fix the bug, ensure that linker-relaxable instructions only appear at the end
of an MCDataFragment, thereby making them terminate the fragment. When computing
A-B, suppress folding if A and B are separated by a linker-relaxable
instruction.

* `.subsection` now correctly give errors for non-foldable expressions.
* gen-dwarf.s will pass even if we add back the .debug_line or .eh_frame/.debug_frame code from D150004
* This will fix suppressed relocation when we add R_RISCV_SET_ULEB128/R_RISCV_SUB_ULEB128.

In the future, we should investigate the desired behavior for
`MCExpr::evaluateAsAbsolute` when both MCAssembler and MCAsmLayout are non-null.

(Note: MCRelaxableFragment is only for assembler-relaxation. If we ever need
linker-relaxable MCRelaxableFragment, we would need to adjust RISCVMCExpr.cpp
(D58943/D73211).)

Depends on D153096

Differential Revision: https://reviews.llvm.org/D153097

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Reland [COFF] Support -gsplit-dwarf for COFF on Windows

This relands 3eee5aa528abd67bb6d057e25ce1980d0d38c445 with fixes.

Revert "[COFF] Support -gsplit-dwarf for COFF on Windows"

This reverts commit 3eee5aa528abd67bb6d057e25ce1980d0d38c445.

Breaks tests on mac, see https://reviews.llvm.org/D152785#4447118

[COFF] Support -gsplit-dwarf for COFF on Windows

D152340 has split WinCOFFObjectWriter to WinCOFFWriter. This patch adds
another WinCOFFWriter as DwoWriter to write Dwo sections to dwo file.
Driver

[COFF] Support -gsplit-dwarf for COFF on Windows

D152340 has split WinCOFFObjectWriter to WinCOFFWriter. This patch adds
another WinCOFFWriter as DwoWriter to write Dwo sections to dwo file.
Driver options are also updated accordingly to support -gsplit-dwarf in
CL mode.

e.g. $ clang-cl -c -gdwarf -gsplit-dwarf foo.c

Like what -gsplit-dwarf did in ELF, using this option will create DWARF object
(.dwo) file. DWARF debug info is split between COFF object and DWARF object
file. It can reduce the executable file size especially for large project.

Reviewed By: skan, MaskRay

Differential Revision: https://reviews.llvm.org/D152785

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[MC][MachO]Do not emit DWARF for no-personality case

Detail: Follow up to D144999, where we emitted DWARF for non-canonical personality.

Reviewed By: jyknight

Differential Revision: https://review

[MC][MachO]Do not emit DWARF for no-personality case

Detail: Follow up to D144999, where we emitted DWARF for non-canonical personality.

Reviewed By: jyknight

Differential Revision: https://reviews.llvm.org/D152540

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Reland "D144999 [MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

Reasons for rolling forward:
- the crash reported from Chromium was fi

Reland "D144999 [MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

Reasons for rolling forward:
- the crash reported from Chromium was fixed in D151824 (not related to this patch at all)
- since D152824 was committed, it should now be safe to roll this forward.

New change:
- add an additional _ in name check

This reverts commit 4980eead4d0b4666d53dad07afb091375b3a13a0.

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Revert "[RFC][MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

This reverts commit 09aaf53a05e3786eea374f3ce57574225036412d.
Causes toolchai

Revert "[RFC][MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

This reverts commit 09aaf53a05e3786eea374f3ce57574225036412d.
Causes toolchain asserts building libc++ for x86_64,
see https://reviews.llvm.org/D144999#4356215

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[RFC][MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs.

Details: https://github.com/rust-lang/rust/issues/102754

The MachO format uses 2 bits

[RFC][MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs.

Details: https://github.com/rust-lang/rust/issues/102754

The MachO format uses 2 bits to encode these personality funtions, with 0 reserved for "no-personality".
This means we can only have up to 3 personality. There are already three popular personalities: __gxx_personality_v0, __gcc_personality_v0, and __objc_personality_v0.
As a result, any system that needs custom-personality will run into a problem.

This patch implemented jyknight's proposal to simply force DWARFs for all non-canonical personality functions.

Differential Revision: https://reviews.llvm.org/D144999

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[ADT] Don't including None.h (NFC)

These source files no longer use None, so they do not need to include
None.h.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://

[ADT] Don't including None.h (NFC)

These source files no longer use None, so they do not need to include
None.h.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

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[MC] llvm::Optional => std::optional

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

[llvm] Use std::nullopt instead of None (NFC)

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of ma

[llvm] Use std::nullopt instead of None (NFC)

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

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[llvm] Remove includes of `llvm/Support/STLArrayExtras.h`

`llvm` and downstream internal callers no longer use `array_lengthof`, so drop
the include everywhere.

Differential Revision: https://revie

[llvm] Remove includes of `llvm/Support/STLArrayExtras.h`

`llvm` and downstream internal callers no longer use `array_lengthof`, so drop
the include everywhere.

Differential Revision: https://reviews.llvm.org/D133600

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[llvm] Use std::size instead of llvm::array_lengthof

LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpf

[llvm] Use std::size instead of llvm::array_lengthof

LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpful for C++17 or later: `std::size` already has support for C-style
arrays.

Change call sites to use `std::size` instead.

Differential Revision: https://reviews.llvm.org/D133429

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[DirectX][MC] Add MC support for DXContainer

DXContainer files resemble traditional object files in that they are
comprised of parts which resemble sections. Adding DXContainer as an
object file for

[DirectX][MC] Add MC support for DXContainer

DXContainer files resemble traditional object files in that they are
comprised of parts which resemble sections. Adding DXContainer as an
object file format in the MC layer will allow emitting DXContainer
objects through the normal object emission pipeline.

Differential Revision: https://reviews.llvm.org/D127165

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[SPIR-V](3/6) Add MC layer, object file support, and InstPrinter

The patch adds SPIRV-specific MC layer implementation, SPIRV object
file support and SPIRVInstPrinter.

Differential Revision: https:

[SPIR-V](3/6) Add MC layer, object file support, and InstPrinter

The patch adds SPIRV-specific MC layer implementation, SPIRV object
file support and SPIRVInstPrinter.

Differential Revision: https://reviews.llvm.org/D116462

Authors: Aleksandr Bezzubikov, Lewis Crawford, Ilia Diachkov,
Michal Paszkowski, Andrey Tretyakov, Konrad Trifunovic

Co-authored-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
Co-authored-by: Ilia Diachkov <iliya.diyachkov@intel.com>
Co-authored-by: Michal Paszkowski <michal.paszkowski@outlook.com>
Co-authored-by: Andrey Tretyakov <andrey1.tretyakov@intel.com>
Co-authored-by: Konrad Trifunovic <konrad.trifunovic@intel.com>

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