[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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[llvm] Remove unneeded cl::ZeroOrMore for cl::opt options. NFC

Some cl::ZeroOrMore were added to avoid the `may only occur zero or one times!`
error. More were added due to cargo cult. Since the err

[llvm] Remove unneeded cl::ZeroOrMore for cl::opt options. NFC

Some cl::ZeroOrMore were added to avoid the `may only occur zero or one times!`
error. More were added due to cargo cult. Since the error has been removed,
cl::ZeroOrMore is unneeded.

Also remove cl::init(false) while touching the lines.

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[NVPTX] Disable DWARF .file directory for PTX

Default behavior for .file directory was changed in D105856, but
ptxas (CUDA 11.5 release) refuses to parse it:

$ llc -march=nvptx64 llvm/test/Debu

[NVPTX] Disable DWARF .file directory for PTX

Default behavior for .file directory was changed in D105856, but
ptxas (CUDA 11.5 release) refuses to parse it:

$ llc -march=nvptx64 llvm/test/DebugInfo/NVPTX/debug-file-loc.ll
$ ptxas debug-file-loc.s
ptxas debug-file-loc.s, line 42; fatal : Parsing error near
'"foo.h"': syntax error

Added a new field to MCAsmInfo to control default value of
UseDwarfDirectory. This value is used if -dwarf-directory command line
option is not specified.

Differential Revision: https://reviews.llvm.org/D121299

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Cleanup codegen includes

This is a (fixed) recommit of https://reviews.llvm.org/D121169

after: 1061034926
before: 1063332844

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-in

Cleanup codegen includes

This is a (fixed) recommit of https://reviews.llvm.org/D121169

after: 1061034926
before: 1063332844

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D121681

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Revert "Cleanup codegen includes"

This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https:/

Revert "Cleanup codegen includes"

This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https://reviews.llvm.org/D121169

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Cleanup codegen includes

after: 1061034926
before: 1063332844

Differential Revision: https://reviews.llvm.org/D121169

mark getTargetTransformInfo and getTargetIRAnalysis as const

Seems like this can be const, since Passes shouldn't modify it.

Reviewed By: wsmoses

Differential Revision: https://reviews.llvm.org/D1

mark getTargetTransformInfo and getTargetIRAnalysis as const

Seems like this can be const, since Passes shouldn't modify it.

Reviewed By: wsmoses

Differential Revision: https://reviews.llvm.org/D120518

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[NFC][MC] remove unused argument `MCRegisterInfo` in `MCCodeEmitter`

Reviewed By: skan

Differential Revision: https://reviews.llvm.org/D119846

Revert "[NFC][MC] remove unused argument `MCRegisterInfo` in `MCCodeEmitter`"

This reverts commit fe25c06cc5bdc2ef9427309f8ec1434aad69dc7a.

[NFC][MC] remove unused argument `MCRegisterInfo` in `MCCodeEmitter`

For ten years, it seems that `MCRegisterInfo` is not used by any target.

Reviewed By: skan

Differential Revision: https://revie

[NFC][MC] remove unused argument `MCRegisterInfo` in `MCCodeEmitter`

For ten years, it seems that `MCRegisterInfo` is not used by any target.

Reviewed By: skan

Differential Revision: https://reviews.llvm.org/D119846

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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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Move TargetRegistry.(h|cpp) from Support to MC

This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually us

Move TargetRegistry.(h|cpp) from Support to MC

This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.

This allows us to ensure that Support doesn't have includes from MC/*.

Differential Revision: https://reviews.llvm.org/D111454

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[AIX] Use AsmParser to do inline asm parsing

Add a flag so that target can choose to use AsmParser for parsing inline asm.
And set the flag by default for AIX.

-no-intergrated-as will override this

[AIX] Use AsmParser to do inline asm parsing

Add a flag so that target can choose to use AsmParser for parsing inline asm.
And set the flag by default for AIX.

-no-intergrated-as will override this default if specified explicitly.

Reviewed By: #powerpc, shchenz

Differential Revision: https://reviews.llvm.org/D105314

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Add -fbinutils-version= to gate ELF features on the specified binutils version

There are two use cases.

Assembler
We have accrued some code gated on MCAsmInfo::useIntegratedAssembler(). Some
featu

Add -fbinutils-version= to gate ELF features on the specified binutils version

There are two use cases.

Assembler
We have accrued some code gated on MCAsmInfo::useIntegratedAssembler(). Some
features are supported by latest GNU as, but we have to use
MCAsmInfo::useIntegratedAs() because the newer versions have not been widely
adopted (e.g. SHF_LINK_ORDER 'o' and 'unique' linkage in 2.35, --compress-debug-sections= in 2.26).

Linker
We want to use features supported only by LLD or very new GNU ld, or don't want
to work around older GNU ld. We currently can't represent that "we don't care
about old GNU ld". You can find such workarounds in a few other places, e.g.
Mips/MipsAsmprinter.cpp PowerPC/PPCTOCRegDeps.cpp X86/X86MCInstrLower.cpp
AArch64 TLS workaround for R_AARCH64_TLSLD_MOVW_DTPREL_* (PR ld/18276),
R_AARCH64_TLSLE_LDST8_TPREL_LO12 (https://bugs.llvm.org/show_bug.cgi?id=36727 https://sourceware.org/bugzilla/show_bug.cgi?id=22969)

Mixed SHF_LINK_ORDER and non-SHF_LINK_ORDER components (supported by LLD in D84001;
GNU ld feature request https://sourceware.org/bugzilla/show_bug.cgi?id=16833 may take a while before available).
This feature allows to garbage collect some unused sections (e.g. fragmented .gcc_except_table).

This patch adds `-fbinutils-version=` to clang and `-binutils-version` to llc.
It changes one codegen place in SHF_MERGE to demonstrate its usage.
`-fbinutils-version=2.35` means the produced object file does not care about GNU
ld<2.35 compatibility. When `-fno-integrated-as` is specified, the produced
assembly can be consumed by GNU as>=2.35, but older versions may not work.

`-fbinutils-version=none` means that we can use all ELF features, regardless of
GNU as/ld support.

Both clang and llc need `parseBinutilsVersion`. Such command line parsing is
usually implemented in `llvm/lib/CodeGen/CommandFlags.cpp` (LLVMCodeGen),
however, ClangCodeGen does not depend on LLVMCodeGen. So I add
`parseBinutilsVersion` to `llvm/lib/Target/TargetMachine.cpp` (LLVMTarget).

Differential Revision: https://reviews.llvm.org/D85474

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Reland "[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline" (again)

This reverts commit 16c8f6e91344ec9840d6aa9ec6b8d0c87a104ca3 with fix.

-Wswitch catched an unhandled en

Reland "[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline" (again)

This reverts commit 16c8f6e91344ec9840d6aa9ec6b8d0c87a104ca3 with fix.

-Wswitch catched an unhandled enum value due to recent commits in
TargetPassConfig.cpp.

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Revert "Reland "[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline""

This reverts commit 21314940c4856e0cb81b664fd2d2117d1b7dc3e3.

Build failure in some bots.

Reland "[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline"

This reverts commit 94427af60c66ffea655a3084825c6c3a9deec1ad (relands
4646de5d75cfce3da4ddeffb6eb8e66e38238800 w

Reland "[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline"

This reverts commit 94427af60c66ffea655a3084825c6c3a9deec1ad (relands
4646de5d75cfce3da4ddeffb6eb8e66e38238800 with fix).

Use "return std::move(AsmStreamer);" instead of "return AsmStreamer;" in
LVMTargetMachine::createMCStreamer. Unlike Clang, GCC seems having trouble
inserting a implicit lvalue->rvalue conversion.

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Revert "[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline"

This reverts commit 4646de5d75cfce3da4ddeffb6eb8e66e38238800.

Some bots have build failure.

[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline

Following up on D67687.
Please refer to the RFC here http://lists.llvm.org/pipermail/llvm-dev/2020-July/143309.html

`Cod

[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline

Following up on D67687.
Please refer to the RFC here http://lists.llvm.org/pipermail/llvm-dev/2020-July/143309.html

`CodeGenPassBuilder` is the NPM counterpart of `TargetPassConfig` with below differences.
- Debugging features (MIR print/verify, disable pass, start/stop-before/after, etc.) living in `TargetPassConfig` are moved to use PassInstrument as much as possible. (Implementation also lives in `TargetPassConfig.cpp`)
- `TargetPassConfig` is a polymorphic base (virtual inheritance) to build the target-dependent pipeline whereas `CodeGenPassBuilder` is the CRTP base/helper to implement the target-dependent pipeline. The motivation is flexibility for targets to customize the pipeline, inlining opportunity, and fits the overall NPM value semantics design.
- `TargetPassConfig` is a legacy immutable pass to declare hooks for targets to customize some target-independent codegen layer behavior. This is partially ported to TargetMachine::options. The rest, such as `createMachineScheduler/createPostMachineScheduler`, are left out for now. They should be implemented in LLVMTargetMachine in the future.

Reviewed By: arsenm, aeubanks

Differential Revision: https://reviews.llvm.org/D83608

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[llvm][clang][mlir] Add checks for the return values from Target::createXXX to prevent protential null deref

All these potential null pointer dereferences are reported by my static analyzer for null

[llvm][clang][mlir] Add checks for the return values from Target::createXXX to prevent protential null deref

All these potential null pointer dereferences are reported by my static analyzer for null smart pointer dereferences, which has a different implementation from `alpha.cplusplus.SmartPtr`.

The checked pointers in this patch are initialized by Target::createXXX functions. When the creator function pointer is not correctly set, a null pointer will be returned, or the creator function may originally return a null pointer.

Some of them may not make sense as they may be checked before entering the function, but I fixed them all in this patch. I submit this fix because 1) similar checks are found in some other places in the LLVM codebase for the same return value of the function; and, 2) some of the pointers are dereferenced before they are checked, which may definitely trigger a null pointer dereference if the return value is nullptr.

Reviewed By: tejohnson, MaskRay, jpienaar

Differential Revision: https://reviews.llvm.org/D91410

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[llc] Use -filetype=null to disable MIR printing

If you use -stop-after or similar options, llc will normally print MIR.
This patch checks for -filetype=null as a special case to disable MIR
printin

[llc] Use -filetype=null to disable MIR printing

If you use -stop-after or similar options, llc will normally print MIR.
This patch checks for -filetype=null as a special case to disable MIR
printing. As the comment says, "The Null output is intended for use for
performance analysis ...", and I found this useful for timing a subset
of the passes that llc runs without the significant overhead of printing
MIR just to send it to /dev/null.

Differential Revision: https://reviews.llvm.org/D89476

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Revert "[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline"

This reverts commit 31ecf8d29d81d196374a562c6d2bd2c25a62861e.
This reverts commit 3fdaa8602a086a3fca5f0fc8527536

Revert "[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline"

This reverts commit 31ecf8d29d81d196374a562c6d2bd2c25a62861e.
This reverts commit 3fdaa8602a086a3fca5f0fc8527536ac659079d0.

There is laying violation for Target->CodeGen.

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[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline

Following up on D67687.
Please refer to the RFC here http://lists.llvm.org/pipermail/llvm-dev/2020-July/143309.html

`Cod

[NewPM][CodeGen] Introduce CodeGenPassBuilder to help build codegen pipeline

Following up on D67687.
Please refer to the RFC here http://lists.llvm.org/pipermail/llvm-dev/2020-July/143309.html

`CodeGenPassBuilder` is the NPM counterpart of `TargetPassConfig` with below differences.
- Debugging features (MIR print/verify, disable pass, start/stop-before/after, etc.) living in `TargetPassConfig` are moved to use PassInstrument as much as possible. (Implementation also lives in `TargetPassConfig.cpp`)
- `TargetPassConfig` is a polymorphic base (virtual inheritance) to build the target-dependent pipeline whereas `CodeGenPassBuilder` is the CRTP base/helper to implement the target-dependent pipeline. The motivation is flexibility for targets to customize the pipeline, inlining opportunity, and fits the overall NPM value semantics design.
- `TargetPassConfig` is a legacy immutable pass to declare hooks for targets to customize some target-independent codegen layer behavior. This is partially ported to TargetMachine::options. The rest, such as `createMachineScheduler/createPostMachineScheduler`, are left out for now. They should be implemented in LLVMTargetMachine in the future.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D83608

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