[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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Remove support for 10.4 Tiger from AsmPrinter

I stumbled on this while trying to tighten Alignment in MCStreamer (D138705).
From the [wikipedia page](https://en.wikipedia.org/wiki/Mac_OS_X_Tiger), l

Remove support for 10.4 Tiger from AsmPrinter

I stumbled on this while trying to tighten Alignment in MCStreamer (D138705).
From the [wikipedia page](https://en.wikipedia.org/wiki/Mac_OS_X_Tiger), last release of MacOSX Tiger was released 15 years ago and is not supported anymore by Apple.

Relevant commit : https://github.com/llvm/llvm-project/commit/9f06f911d197577b80d208a167980833b4fb9ad5#diff-17b326b45ef392288420bed274616afa7df81b27576c96723b3c25f5198dc398

Differential Revision: https://reviews.llvm.org/D138707

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[SampleFDO] Persist profile staleness metrics into binary

With https://reviews.llvm.org/D136627, now we have the metrics for profile staleness based on profile statistics, monitoring the profile sta

[SampleFDO] Persist profile staleness metrics into binary

With https://reviews.llvm.org/D136627, now we have the metrics for profile staleness based on profile statistics, monitoring the profile staleness in real-time can help user quickly identify performance issues. For a production scenario, the build is usually incremental and if we want the real-time metrics, we should store/cache all the old object's metrics somewhere and pull them in a post-build time. To make it more convenient, this patch add an option to persist them into the object binary, the metrics can be reported right away by decoding the binary rather than polling the previous stdout/stderrs from a cache system.

For implementation, it writes the statistics first into a new metadata section(llvm.stats) then encode into a special ELF `.llvm_stats` section. The section data is formatted as a list of key/value pair so that future statistics can be easily extended. This is also under a new switch(`-persist-profile-staleness`)

In terms of size overhead, the metrics are computed at module level, so the size overhead should be small, measured on one of our internal service, it costs less than < 1MB for a 10GB+ binary.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D136698

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[PseudoProbe] Replace relocation with offset for entry probe.

Currently pseudo probe encoding for a function is like:
- For the first probe, a relocation from it to its physical position in the cod

[PseudoProbe] Replace relocation with offset for entry probe.

Currently pseudo probe encoding for a function is like:
- For the first probe, a relocation from it to its physical position in the code body
- For subsequent probes, an incremental offset from the current probe to the previous probe

The relocation could potentially cause relocation overflow during link time. I'm now replacing it with an offset from the first probe to the function start address.

A source function could be lowered into multiple binary functions due to outlining (e.g, coro-split). Since those binary function have independent link-time layout, to really avoid relocations from .pseudo_probe sections to .text sections, the offset to replace with should really be the offset from the probe's enclosing binary function, rather than from the entry of the source function. This requires some changes to previous section-based emission scheme which now switches to be function-based. The assembly form of pseudo probe directive is also changed correspondingly, i.e, reflecting the binary function name.

Most of the source functions end up with only one binary function. For those don't, a sentinel probe is emitted for each of the binary functions with a different name from the source. The sentinel probe indicates the binary function name to differentiate subsequent probes from the ones from a different binary function. For examples, given source function

```
Foo() {
…
Probe 1
…
Probe 2
}
```

If it is transformed into two binary functions:

```
Foo:
…

Foo.outlined:
…
```

The encoding for the two binary functions will be separate:

```

GUID of Foo
Probe 1

GUID of Foo
Sentinel probe of Foo.outlined
Probe 2
```

Then probe1 will be decoded against binary `Foo`'s address, and Probe 2 will be decoded against `Foo.outlined`. The sentinel probe of `Foo.outlined` makes sure there's not accidental relocation from `Foo.outlined`'s probes to `Foo`'s entry address.

On the BOLT side, to be minimal intrusive, the pseudo probe re-encoding sticks with the old encoding format. This is fine since unlike linker, Bolt processes the pseudo probe section as a whole and it is free from relocation overflow issues.

The change is downwards compatible as long as there's no mixed use of the old encoding and the new encoding.

Reviewed By: wenlei, maksfb

Differential Revision: https://reviews.llvm.org/D135912
Differential Revision: https://reviews.llvm.org/D135914
Differential Revision: https://reviews.llvm.org/D136394

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[AsmPrinter] Emit PCs into requested PCSections

Interpret MD_pcsections in AsmPrinter emitting the requested metadata to
the associated sections. Functions and normal instructions are handled.

Diff

[AsmPrinter] Emit PCs into requested PCSections

Interpret MD_pcsections in AsmPrinter emitting the requested metadata to
the associated sections. Functions and normal instructions are handled.

Differential Revision: https://reviews.llvm.org/D130879

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KCFI sanitizer

The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type ide

KCFI sanitizer

The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type identifier for each
function and injects verification code before indirect calls.

Unlike the current CFI schemes implemented in LLVM, KCFI does not
require LTO, does not alter function references to point to a jump
table, and never breaks function address equality. KCFI is intended
to be used in low-level code, such as operating system kernels,
where the existing schemes can cause undue complications because
of the aforementioned properties. However, unlike the existing
schemes, KCFI is limited to validating only function pointers and is
not compatible with executable-only memory.

KCFI does not provide runtime support, but always traps when a
type mismatch is encountered. Users of the scheme are expected
to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi`
operand bundle to indirect calls, and LLVM lowers this to a
known architecture-specific sequence of instructions for each
callsite to make runtime patching easier for users who require this
functionality.

A KCFI type identifier is a 32-bit constant produced by taking the
lower half of xxHash64 from a C++ mangled typename. If a program
contains indirect calls to assembly functions, they must be
manually annotated with the expected type identifiers to prevent
errors. To make this easier, Clang generates a weak SHN_ABS
`__kcfi_typeid_<function>` symbol for each address-taken function
declaration, which can be used to annotate functions in assembly
as long as at least one C translation unit linked into the program
takes the function address. For example on AArch64, we might have
the following code:

```
.c:
int f(void);
int (*p)(void) = f;
p();

.s:
.4byte __kcfi_typeid_f
.global f
f:
...
```

Note that X86 uses a different preamble format for compatibility
with Linux kernel tooling. See the comments in
`X86AsmPrinter::emitKCFITypeId` for details.

As users of KCFI may need to locate trap locations for binary
validation and error handling, LLVM can additionally emit the
locations of traps to a `.kcfi_traps` section.

Similarly to other sanitizers, KCFI checking can be disabled for a
function with a `no_sanitize("kcfi")` function attribute.

Relands 67504c95494ff05be2a613129110c9bcf17f6c13 with a fix for
32-bit builds.

Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay

Differential Revision: https://reviews.llvm.org/D119296

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Revert "KCFI sanitizer"

This reverts commit 67504c95494ff05be2a613129110c9bcf17f6c13 as using
PointerEmbeddedInt to store 32 bits breaks 32-bit arm builds.

KCFI sanitizer

The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type ide

KCFI sanitizer

The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type identifier for each
function and injects verification code before indirect calls.

Unlike the current CFI schemes implemented in LLVM, KCFI does not
require LTO, does not alter function references to point to a jump
table, and never breaks function address equality. KCFI is intended
to be used in low-level code, such as operating system kernels,
where the existing schemes can cause undue complications because
of the aforementioned properties. However, unlike the existing
schemes, KCFI is limited to validating only function pointers and is
not compatible with executable-only memory.

KCFI does not provide runtime support, but always traps when a
type mismatch is encountered. Users of the scheme are expected
to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi`
operand bundle to indirect calls, and LLVM lowers this to a
known architecture-specific sequence of instructions for each
callsite to make runtime patching easier for users who require this
functionality.

A KCFI type identifier is a 32-bit constant produced by taking the
lower half of xxHash64 from a C++ mangled typename. If a program
contains indirect calls to assembly functions, they must be
manually annotated with the expected type identifiers to prevent
errors. To make this easier, Clang generates a weak SHN_ABS
`__kcfi_typeid_<function>` symbol for each address-taken function
declaration, which can be used to annotate functions in assembly
as long as at least one C translation unit linked into the program
takes the function address. For example on AArch64, we might have
the following code:

```
.c:
int f(void);
int (*p)(void) = f;
p();

.s:
.4byte __kcfi_typeid_f
.global f
f:
...
```

Note that X86 uses a different preamble format for compatibility
with Linux kernel tooling. See the comments in
`X86AsmPrinter::emitKCFITypeId` for details.

As users of KCFI may need to locate trap locations for binary
validation and error handling, LLVM can additionally emit the
locations of traps to a `.kcfi_traps` section.

Similarly to other sanitizers, KCFI checking can be disabled for a
function with a `no_sanitize("kcfi")` function attribute.

Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay

Differential Revision: https://reviews.llvm.org/D119296

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Emit a simple StackSizesSection on PS4.

Differential Revision: https://reviews.llvm.org/D130495

[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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[MC][re-land] Omit DWARF unwind info if compact unwind is present where eligible

This reverts commit d941d597837d9e1405086f008c9bd6a71e7263c9.

Differential Revision: https://reviews.llvm.org/D122258

Revert "[MC] Omit DWARF unwind info if compact unwind is present where eligible"

This reverts commit ef501bf85d8c869248e51371f0e74bcec0e7b229.

[MC] Omit DWARF unwind info if compact unwind is present where eligible

Previously, omitting unnecessary DWARF unwinds was only done in two
cases:
* For Darwin + aarch64, if no DWARF unwind info is

[MC] Omit DWARF unwind info if compact unwind is present where eligible

Previously, omitting unnecessary DWARF unwinds was only done in two
cases:
* For Darwin + aarch64, if no DWARF unwind info is needed for all the
functions in a TU, then the `__eh_frame` section would be omitted
entirely. If any one function needed DWARF unwind, then MC would emit
DWARF unwind entries for all the functions in the TU.
* For watchOS, MC would omit DWARF unwind on a per-function basis, as
long as compact unwind was available for that function.

This diff makes it so that we omit DWARF unwind on a per-function basis
for Darwin + aarch64 as well. In addition, we introduce the flag
`--emit-dwarf-unwind=` which can toggle between `always`,
`no-compact-unwind` (only emit DWARF when CU cannot be emitted for a
given function), and the target platform `default`. `no-compact-unwind`
is particularly useful for newer x86_64 platforms: we don't want to omit
DWARF unwind for x86_64 in general due to possible backwards compat
issues, but we should make it possible for people to opt into this
behavior if they are only targeting newer platforms.

**Motivation:** I'm working on adding support for `__eh_frame` to LLD,
but I'm concerned that we would suffer a perf hit. Processing compact
unwind is already expensive, and that's a simpler format than EH frames.
Given that MC currently produces one EH frame entry for every compact
unwind entry, I don't think processing them will be cheap. I tried to do
something clever on LLD's end to drop the unnecessary EH frames at parse
time, but this made the code significantly more complex. So I'm looking
at fixing this at the MC level instead.

**Addendum:** It turns out that there was a latent bug in the X86
backend when `OmitDwarfIfHaveCompactUnwind` is naively enabled, which is
not too surprising given that this combination has not been heretofore
used.

For functions that have unwind info that cannot be encoded with CU, MC
would end up dropping both the compact unwind entry (OK; existing
behavior) as well as the DWARF entries (not OK). This diff fixes things
so that we emit the DWARF entry, as well as a CU entry with encoding
`UNWIND_X86_MODE_DWARF` -- this basically tells the unwinder to look for
the DWARF entry. I'm not 100% sure the `UNWIND_X86_MODE_DWARF` CU entry
is necessary, this was the simplest fix. ld64 seems to be able to handle
both the absence and presence of this CU entry. Ultimately ld64 (and
LLD) will synthesize `UNWIND_X86_MODE_DWARF` if it is absent, so there
is no impact to the final binary size.

Reviewed By: davide, lhames

Differential Revision: https://reviews.llvm.org/D122258

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[ARM] [MinGW] Default to WinEH exception handling instead of Dwarf

Switching this target to WinEH also seems to affect the `-windows-itanium`
target.

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

[ARM] [MinGW] Default to WinEH exception handling instead of Dwarf

Switching this target to WinEH also seems to affect the `-windows-itanium`
target.

Differential Revision: https://reviews.llvm.org/D126870

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[SystemZ][z/OS] Add the PPA1 to SystemZAsmPrinter

Differential Revision: https://reviews.llvm.org/D125725

Implement support for __llvm_addrsig for MachO in llvm-mc

The __llvm_addrsig section is a section that the linker needs for safe icf.
This was not yet implemented for MachO - this is the implementat

Implement support for __llvm_addrsig for MachO in llvm-mc

The __llvm_addrsig section is a section that the linker needs for safe icf.
This was not yet implemented for MachO - this is the implementation.
It has been tested with a safe deduplication implementation inside lld.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D123751

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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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Add DXContainer

DXIL is wrapped in a container format defined by the DirectX 11
specification. Codebases differ in calling this format either DXBC or
DXILContainer.

Since eventually we want to add

Add DXContainer

DXIL is wrapped in a container format defined by the DirectX 11
specification. Codebases differ in calling this format either DXBC or
DXILContainer.

Since eventually we want to add support for DXBC as a target
architecture and the format is used by DXBC and DXIL, I've termed it
DXContainer here.

Most of the changes in this patch are just adding cases to switch
statements to address warnings.

Reviewed By: pete

Differential Revision: https://reviews.llvm.org/D122062

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Cleanup LLVMMC headers

There's a few relevant forward declarations in there that may require downstream
adding explicit includes:

llvm/MC/MCContext.h no longer includes llvm/BinaryFormat/ELF.h, llv

Cleanup LLVMMC headers

There's a few relevant forward declarations in there that may require downstream
adding explicit includes:

llvm/MC/MCContext.h no longer includes llvm/BinaryFormat/ELF.h, llvm/MC/MCSubtargetInfo.h, llvm/MC/MCTargetOptions.h
llvm/MC/MCObjectStreamer.h no longer include llvm/MC/MCAssembler.h
llvm/MC/MCAssembler.h no longer includes llvm/MC/MCFixup.h, llvm/MC/MCFragment.h

Counting preprocessed lines required to rebuild llvm-project on my setup:
before: 1052436830
after: 1049293745

Which is significant and backs up the change in addition to the usual benefits of
decreasing coupling between headers and compilation units.

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D119244

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[llvm] Use = default (NFC)

Change namespace llvm::swift to namespace llvm::binaryformat because of clashes with the apple/llvm-project repository

The namespace llvm::swift is causing errors to pop up in the apple/llvm-project

Change namespace llvm::swift to namespace llvm::binaryformat because of clashes with the apple/llvm-project repository

The namespace llvm::swift is causing errors to pop up in the apple/llvm-project build when cherry-picking 4ce1f3d47c33 into apple/llvm-project

Differential Review: https://reviews.llvm.org/D118716

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Emit swift5 reflection section data in dsym bundle generated by dsymutil in the Dwarf section.

Add support for Swift reflection metadata to dsymutil.

This patch adds support for copying Swift refle

Emit swift5 reflection section data in dsym bundle generated by dsymutil in the Dwarf section.

Add support for Swift reflection metadata to dsymutil.

This patch adds support for copying Swift reflection metadata (__swift5_.* sections) from .o files to into the symbol-rich binary in the output .dSYM. The functionality is automatically enabled only if a .o file has reflection metadata sections and the binary doesn't. When copying dsymutil moves the section from the __TEXT segment to the __DWARF segment.

rdar://76973336

Differential Revision: https://reviews.llvm.org/D115007

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Revert "Emit swift5 reflection section data in dsym bundle generated by dsymutil in the Dwarf section."

This reverts commit 50f50f2582993a079dbcfb8e7ba48920f41e6be0.

Emit swift5 reflection section data in dsym bundle generated by dsymutil in the Dwarf section.

Add support for Swift reflection metadata to dsymutil.

This patch adds support for copying Swift refle

Emit swift5 reflection section data in dsym bundle generated by dsymutil in the Dwarf section.

Add support for Swift reflection metadata to dsymutil.

This patch adds support for copying Swift reflection metadata (__swift5_.* sections) from .o files to into the symbol-rich binary in the output .dSYM. The functionality is automatically enabled only if a .o file has reflection metadata sections and the binary doesn't. When copying dsymutil moves the section from the __TEXT segment to the __DWARF segment.

rdar://76973336

Differential Revision: https://reviews.llvm.org/D115007

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Revert "Emit swift5 reflection section data in dsym bundle generated by dsymutil in the Dwarf section."

This reverts commit d84d1135d80c1dead6564347943ba56eed5aac3b. to investigate buildbot failures