[DeadArgElim] Replace insert with emplace (NFC)

[DeadArgElim] Reformat the pass in accordance with the code style

The code has been reformatted in accordance with the code style. Some
function comments were extended to the Doxygen ones and reword

[DeadArgElim] Reformat the pass in accordance with the code style

The code has been reformatted in accordance with the code style. Some
function comments were extended to the Doxygen ones and reworded a bit
to eliminate the duplication of the function's/class' name in the
comment.

Differential Revision: https://reviews.llvm.org/D128168

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[llvm] Add DW_CC_nocall to function debug metadata when either return values or arguments are removed

Adding the `DW_CC_nocall` calling convention to the function debug metadata is needed when eithe

[llvm] Add DW_CC_nocall to function debug metadata when either return values or arguments are removed

Adding the `DW_CC_nocall` calling convention to the function debug metadata is needed when either the return values or the arguments of a function are removed as this helps in informing debugger that it may not be safe to call this function or try to interpret the return value.
This translates to setting `DW_AT_calling_convention` with `DW_CC_nocall` for appropriate DWARF DIEs.

The DWARF5 spec (section 3.3.1.1 Calling Convention Information) says:

If the `DW_AT_calling_convention` attribute is not present, or its value is the constant `DW_CC_normal`, then the subroutine may be safely called by obeying the `standard` calling conventions of the target architecture. If the value of the calling convention attribute is the constant `DW_CC_nocall`, the subroutine does not obey standard calling conventions, and it may not be safe for the debugger to call this subroutine.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D127134

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[DeadArgElim] Remove dead code after r128810

[DeadArgElim] Use poison instead of undef as placeholder for dead arguments

It doesn't matter which value we use for dead args, so let's switch
to poison, so we can eventually kill undef.

Reviewed

[DeadArgElim] Use poison instead of undef as placeholder for dead arguments

It doesn't matter which value we use for dead args, so let's switch
to poison, so we can eventually kill undef.

Reviewed By: aeubanks, fhahn

Differential Revision: https://reviews.llvm.org/D125983

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[DeadArgElim] Re-apply: Set unused arguments for internal functions

The re-apply includes fixes to clang tests that were missed in
the original commit.

Original message:
Prior to this patch we woul

[DeadArgElim] Re-apply: Set unused arguments for internal functions

The re-apply includes fixes to clang tests that were missed in
the original commit.

Original message:
Prior to this patch we would only set to undef the unused arguments of the
external functions. The rationale was that unused arguments of internal
functions wouldn't need to be turned into undef arguments because they
should have been simply eliminated by the time we reach that code.

This is actually not true because there are plenty of cases where we can't
remove unused arguments. For instance, if the internal function is used in
an indirect call, it may not be possible to change the function signature.
Yet, for statically known call-sites we would still like to mark the unused
arguments as undef.

This patch enables the "set undef arguments" optimization on internal
functions when we encounter cases where internal functions cannot be
optimized. I.e., whenever an internal function is marked "live".

Differential Revision: https://reviews.llvm.org/D124699

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Revert "[DeadArgElim] Set unused arguments for internal functions"

Breaks bots, see https://reviews.llvm.org/D124699

This reverts commit e547a333a43348a8a7ec9460f37696ecc5453e56.

[DeadArgElim] Set unused arguments for internal functions

Prior to this patch we would only set to undef the unused arguments of the
external functions. The rationale was that unused arguments of in

[DeadArgElim] Set unused arguments for internal functions

Prior to this patch we would only set to undef the unused arguments of the
external functions. The rationale was that unused arguments of internal
functions wouldn't need to be turned into undef arguments because they
should have been simply eliminated by the time we reach that code.

This is actually not true because there are plenty of cases where we can't
remove unused arguments. For instance, if the internal function is used in
an indirect call, it may not be possible to change the function signature.
Yet, for statically known call-sites we would still like to mark the unused
arguments as undef.

This patch enables the "set undef arguments" optimization on internal
functions when we encounter cases where internal functions cannot be
optimized. I.e., whenever an internal function is marked "live".

Differential Revision: https://reviews.llvm.org/D124699

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Cleanup includes: Transforms/IPO

Preprocessor output diff: -238205 lines
Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.ll

Cleanup includes: Transforms/IPO

Preprocessor output diff: -238205 lines
Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D122183

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[DeadArgElim] Guard against function type mismatch

If the call function type and function type don't match, we should
consider the function live (there is effectively a bitcast
sitting in between).

[DeadArgElim] Check that function type is the same

If the function types differ, the call arguments don't necessarily
correspon to the function arguments. It's likely not worthwhile to
handle this m

[DeadArgElim] Check that function type is the same

If the function types differ, the call arguments don't necessarily
correspon to the function arguments. It's likely not worthwhile to
handle this more precisely, but at least we shouldn't crash.

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Use a sorted array instead of a map to store AttrBuilder string attributes

Using and std::map<SmallString, SmallString> for target dependent attributes is
inefficient: it makes its constructor sligh

Use a sorted array instead of a map to store AttrBuilder string attributes

Using and std::map<SmallString, SmallString> for target dependent attributes is
inefficient: it makes its constructor slightly heavier, and involves extra
allocation for each new string attribute. Storing the attribute key/value as
strings implies extra allocation/copy step.

Use a sorted vector instead. Given the low number of attributes generally
involved, this is cheaper, as showcased by

https://llvm-compile-time-tracker.com/compare.php?from=5de322295f4ade692dc4f1823ae4450ad3c48af2&to=05bc480bf641a9e3b466619af43a2d123ee3f71d&stat=instructions

Differential Revision: https://reviews.llvm.org/D116599

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Introduce the AttributeMask class

This class is solely used as a lightweight and clean way to build a set of
attributes to be removed from an AttrBuilder. Previously AttrBuilder was used
both for bu

Introduce the AttributeMask class

This class is solely used as a lightweight and clean way to build a set of
attributes to be removed from an AttrBuilder. Previously AttrBuilder was used
both for building and removing, which introduced odd situation like creation of
Attribute with dummy value because the only relevant part was the attribute
kind.

Differential Revision: https://reviews.llvm.org/D116110

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[Transforms] Use make_early_inc_range (NFC)

[IPO] Use make_early_inc_range (NFC)

[NFC] Rename AttributeList::getParam/Ret/FnAttributes() -> get*Attributes()

This is more consistent with similar methods.

[NFC] Remove AttributeList::hasParamAttribute()

It's the same as AttributeList::hasParamAttr().

[Attributes] Clean up handling of UB implying attributes (NFC)

Rather than adding methods for dropping these attributes in
various places, add a function that returns an AttrBuilder with
these attri

[Attributes] Clean up handling of UB implying attributes (NFC)

Rather than adding methods for dropping these attributes in
various places, add a function that returns an AttrBuilder with
these attributes, which can then be used with existing methods
for dropping attributes. This is with an eye on D104641, which
also needs to drop them from returns, not just parameters.

Also be more explicit about the semantics of the method in the
documentation. Refer to UB rather than Undef, which is what this
is actually about.

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[DAE] Adjust param/arg attributes when changing parameter to undef

In DeadArgumentElimination pass, if a function's argument is never used, corresponding caller's parameter can be changed to undef.

[DAE] Adjust param/arg attributes when changing parameter to undef

In DeadArgumentElimination pass, if a function's argument is never used, corresponding caller's parameter can be changed to undef. If the param/arg has attribute noundef or other related attributes, LLVM LangRef(https://llvm.org/docs/LangRef.html#parameter-attributes) says its behavior is undefined. SimplifyCFG(D97244) takes advantage of this behavior and does bad transformation on valid code.

To avoid this undefined behavior when change caller's parameter to undef, this patch removes noundef attribute and other attributes imply noundef on param/arg.

Differential Revision: https://reviews.llvm.org/D98899

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Revert "[ObjC][ARC] Annotate calls with attributes instead of emitting retainRV"

This reverts commit 53176c168061d6f26dcf3ce4fa59288b7d67255e, which
introduceed a layering violation. LLVM's IR libra

Revert "[ObjC][ARC] Annotate calls with attributes instead of emitting retainRV"

This reverts commit 53176c168061d6f26dcf3ce4fa59288b7d67255e, which
introduceed a layering violation. LLVM's IR library can't include
headers from Analysis.

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[ObjC][ARC] Annotate calls with attributes instead of emitting retainRV
or claimRV calls in the IR

Background:

This patch makes changes to the front-end and middle-end that are
needed to fix a long

[ObjC][ARC] Annotate calls with attributes instead of emitting retainRV
or claimRV calls in the IR

Background:

This patch makes changes to the front-end and middle-end that are
needed to fix a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.

https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue

What this patch does to fix the problem:

- The front-end annotates calls with attribute "clang.arc.rv"="retain"
or "clang.arc.rv"="claim", which indicates the call is implicitly
followed by a marker instruction and a retainRV/claimRV call that
consumes the call result. This is currently done only when the target
is arm64 and the optimization level is higher than -O0.

- ARC optimizer temporarily emits retainRV/claimRV calls after the
annotated calls in the IR and removes the inserted calls after
processing the function.

- ARC contract pass emits retainRV/claimRV calls after the annotated
calls. It doesn't remove the attribute on the call since the backend
needs it to emit the marker instruction. The retainRV/claimRV calls
are emitted late in the pipeline to prevent optimization passes from
transforming the IR in a way that makes it harder for the ARC
middle-end passes to figure out the def-use relationship between the
call and the retainRV/claimRV calls (which is the cause of PR31925).

- The function inliner removes the autoreleaseRV call in the callee that
returns the result if nothing in the callee prevents it from being
paired up with the calls annotated with "clang.arc.rv"="retain/claim"
in the caller. If the call is annotated with "claim", a release call
is inserted since autoreleaseRV+claimRV is equivalent to a release. If
it cannot find an autoreleaseRV call, it tries to transfer the
attributes to a function call in the callee. This is important since
ARC optimizer can remove the autoreleaseRV call returning the callee
result, which makes it impossible to pair it up with the retainRV or
claimRV call in the caller. If that fails, it simply emits a retain
call in the IR if the call is annotated with "retain" and does nothing
if it's annotated with "claim".

- This patch teaches dead argument elimination pass not to change the
return type of a function if any of the calls to the function are
annotated with attribute "clang.arc.rv". This is necessary since the
pass can incorrectly determine nothing in the IR uses the function
return, which can happen since the front-end no longer explicitly
emits retainRV/claimRV calls in the IR, and change its return type to
'void'.

Future work:

- Use the attribute on x86-64.

- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
calls annotated with the attributes.

rdar://71443534

Differential Revision: https://reviews.llvm.org/D92808

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[DAE] MarkLive in MarkValue(MaybeLive) if any use is live

While looping through all args or all return values, we may mark a use
of a later iteration as live. Previously when we got to that later va

[DAE] MarkLive in MarkValue(MaybeLive) if any use is live

While looping through all args or all return values, we may mark a use
of a later iteration as live. Previously when we got to that later value
it would ignore that and continue adding to Uses instead of marking it
live. For example, when looping through arg#0 and arg#1,
MarkValue(arg#0, Live) may cause some use of arg#1 to be live, but
MarkValue(arg#1, MaybeLive) will not notice that and continue adding
into Uses.

Now MarkValue(RA, MaybeLive) will MarkLive(RA) if any use is live.

Fixes PR47444.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D88529

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IR: Rename Argument::hasPassPointeeByValueAttr to prepare for byref

When the byref attribute is added, there will need to be two similar
functions for the existing cases which have an associate valu

IR: Rename Argument::hasPassPointeeByValueAttr to prepare for byref

When the byref attribute is added, there will need to be two similar
functions for the existing cases which have an associate value copy,
and byref which does not. Most, but not all of the existing uses will
use the existing version.

The associated size function added by D82679 also needs to
contextually differ, and will help eliminate a few places still
relying on pointee element types.

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[deadargelim] Attach dbg info to the insert/extractvalue instructions

Attach DbgLoc on insertvalue/extractvalue instructions created by
DeadArgumentElimination.

This fixes the PR46350.

Differentia

[deadargelim] Attach dbg info to the insert/extractvalue instructions

Attach DbgLoc on insertvalue/extractvalue instructions created by
DeadArgumentElimination.

This fixes the PR46350.

Differential Revision: https://reviews.llvm.org/D81939

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[Instruction] Remove setProfWeight()

Remove the function Instruction::setProfWeight() and make
use of Instruction::copyMetadata(.., {LLVMContext::MD_prof}).
This is correct for all use cases of setP

[Instruction] Remove setProfWeight()

Remove the function Instruction::setProfWeight() and make
use of Instruction::copyMetadata(.., {LLVMContext::MD_prof}).
This is correct for all use cases of setProfWeight() as it
is applied to CallBase instructions only.
This change results in prof metadata copied intact even if
the source has "VP". The old pair of calls
extractProfTotalWeight() + setProfWeight() resulted in
setting branch_weights if the source had "VP" data.

Reviewers: yamauchi, davidxl
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80987

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