[llvm] A Unified LTO Bitcode Frontend

Here's a high level summary of the changes in this patch. For more
information on rational, see the RFC.
(https://discourse.llvm.org/t/rfc-a-unified-lto-bitcode

[llvm] A Unified LTO Bitcode Frontend

Here's a high level summary of the changes in this patch. For more
information on rational, see the RFC.
(https://discourse.llvm.org/t/rfc-a-unified-lto-bitcode-frontend/61774).

- Add config parameter to LTO backend, specifying which LTO mode is
desired when using unified LTO.
- Add unified LTO flag to the summary index for efficiency. Unified
LTO modules can be detected without parsing the module.
- Make sure that the ModuleID is generated by incorporating more types
of symbols.

Differential Revision: https://reviews.llvm.org/D123803

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Add a type_checked_load_relative to support relative function pointer tables

This adds a type_checked_load_relative intrinsic whose semantics it is to
load a relative function pointer.

A relative f

Add a type_checked_load_relative to support relative function pointer tables

This adds a type_checked_load_relative intrinsic whose semantics it is to
load a relative function pointer.

A relative function pointer is a pointer to a 32bit value that when
added to its address yields the address of the function.

Differential Revision: https://reviews.llvm.org/D143204

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[MemProf] Context disambiguation cloning pass [patch 4/4]

Applies ThinLTO cloning decisions made during the thin link and
recorded in the summary index to the IR during the ThinLTO backend.

Depends

[MemProf] Context disambiguation cloning pass [patch 4/4]

Applies ThinLTO cloning decisions made during the thin link and
recorded in the summary index to the IR during the ThinLTO backend.

Depends on D141077.

Differential Revision: https://reviews.llvm.org/D149117

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[ThinLTO] Remove BlockCount for non partial sample profile builds

As pointed out in
https://discourse.llvm.org/t/undeterministic-thin-index-file/69985, the
block count added to distributed ThinLTO i

[ThinLTO] Remove BlockCount for non partial sample profile builds

As pointed out in
https://discourse.llvm.org/t/undeterministic-thin-index-file/69985, the
block count added to distributed ThinLTO index files breaks incremental
builds on ThinLTO - if any linked file has a different number of BBs,
then the accumulated sum placed in the index files will change, causing
all ThinLTO backend compiles to be redone.

The block count is only used for scaling of partial sample profiles, and
was added in D80403 for D79831.

This patch simply removes this field from the index files of non partial
sample profile compiles, which is NFC on the output of the compiler.

We subsequently need to see if this can be removed for partial sample
profiles without signficant performance loss, or redesigned in a way
that does not destroy caching.

Differential Revision: https://reviews.llvm.org/D148746

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Revert "[llvm] Teach whole program devirtualization about relative vtables"

This reverts commit db288184765c0b4010060ebea1f6de3ac1f66445.

Reverting since it broke our lto builders reported by fxbug

Revert "[llvm] Teach whole program devirtualization about relative vtables"

This reverts commit db288184765c0b4010060ebea1f6de3ac1f66445.

Reverting since it broke our lto builders reported by fxbug.dev/123807.

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[llvm] Teach whole program devirtualization about relative vtables

Prior to this patch, WPD was not acting on relative-vtables in C++. This
involves teaching WPD about these things:

- llvm.load.rel

[llvm] Teach whole program devirtualization about relative vtables

Prior to this patch, WPD was not acting on relative-vtables in C++. This
involves teaching WPD about these things:

- llvm.load.relative which is how relative-vtables are indexed (instead of GEP)
- dso_local_equivalent which is used in the vtable itself when taking the
offset between a virtual function and vtable
- Update llvm/test/ThinLTO/X86/devirt.ll to use opaque pointers and add
equivalent tests for RV

Differential Revision: https://reviews.llvm.org/D134320

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[ThinLTO/WPD] Handle function alias in vtable correctly

We were not summarizing a function alias in the vtable, leading to
incorrect WPD in some cases, and missing WPD in others.

Specifically, we w

[ThinLTO/WPD] Handle function alias in vtable correctly

We were not summarizing a function alias in the vtable, leading to
incorrect WPD in some cases, and missing WPD in others.

Specifically, we would end up ignoring function aliases as they aren't
summarized, so we could incorrectly devirtualize if there was a single
other non-alias function in a compatible vtable. And if there was only
one implementation, but it was an alias, we would not be able to
identify and perform the single implementation devirtualization.

Handling the alias summary correctly also required fixing the handling
in mustBeUnreachableFunction, so that it is not incorrectly ignored.

Regular LTO is conservatively correct because it will skip
devirtualizing when any pointer within a vtable is not a function.
However, it needs additional work to be able to take advantage of
function alias within the vtable that is in fact the only
implementation. For that reason, the Regular LTO testing in the second
test case is currently disabled, and will be enabled along with a follow
on enhancement fix for Regular LTO WPD.

Differential Revision: https://reviews.llvm.org/D144209

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ModuleSummaryAnalysis: Internalize some cl::opt

Restore "[MemProf] ThinLTO summary support" with more fixes

This restores commit 98ed423361de2f9dc0113a31be2aa04524489ca9 and
follow on fix 00c22351ba697dbddb4b5bf0ad94e4bcea4b316b, which were
rever

Restore "[MemProf] ThinLTO summary support" with more fixes

This restores commit 98ed423361de2f9dc0113a31be2aa04524489ca9 and
follow on fix 00c22351ba697dbddb4b5bf0ad94e4bcea4b316b, which were
reverted in 5d938eb6f79b16f55266dd23d5df831f552ea082 due to an
MSVC bot failure. I've included a fix for that failure.

Differential Revision: https://reviews.llvm.org/D135714

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Revert "Restore "[MemProf] ThinLTO summary support" with fixes"

This reverts commit 00c22351ba697dbddb4b5bf0ad94e4bcea4b316b.
This reverts commit 98ed423361de2f9dc0113a31be2aa04524489ca9.

Seemingly

Revert "Restore "[MemProf] ThinLTO summary support" with fixes"

This reverts commit 00c22351ba697dbddb4b5bf0ad94e4bcea4b316b.
This reverts commit 98ed423361de2f9dc0113a31be2aa04524489ca9.

Seemingly MSVC has some kind of issue with this patch, in terms of linking:

https://lab.llvm.org/buildbot/#/builders/123/builds/14137

I'll post more detail on D135714 momentarily.

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Restore "[MemProf] ThinLTO summary support" with fixes

This restores 47459455009db4790ffc3765a2ec0f8b4934c2a4, which was
reverted in commit 452a14efc84edf808d1e2953dad2c694972b312f, along with
fixes

Restore "[MemProf] ThinLTO summary support" with fixes

This restores 47459455009db4790ffc3765a2ec0f8b4934c2a4, which was
reverted in commit 452a14efc84edf808d1e2953dad2c694972b312f, along with
fixes for a couple of bot failures.

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Revert "[MemProf] ThinLTO summary support"

This reverts commit 47459455009db4790ffc3765a2ec0f8b4934c2a4.

Revert while I try to fix a couple of non-Linux build failures.

[MemProf] ThinLTO summary support

Implements the ThinLTO summary support for memprof related metadata.

This includes support for the assembly format, and for building the
summary from IR during Mod

[MemProf] ThinLTO summary support

Implements the ThinLTO summary support for memprof related metadata.

This includes support for the assembly format, and for building the
summary from IR during ModuleSummaryAnalysis.

To reduce space in both the bitcode format and the in memory index,
we do 2 things:
1. We keep a single vector of all uniq stack id hashes, and record the
index into this vector in the callsite and allocation memprof
summaries.
2. When building the combined index during the LTO link, the callsite
and allocation memprof summaries are only kept on the FunctionSummary
of the prevailing copy.

Differential Revision: https://reviews.llvm.org/D135714

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Revert "[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm"

This reverts commit bf8381a8bce28fc69857645cc7e84a72317e693e.

There is a layering violation: LLVMAnalysis depends on

Revert "[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm"

This reverts commit bf8381a8bce28fc69857645cc7e84a72317e693e.

There is a layering violation: LLVMAnalysis depends on LLVMCore, so
LLVMCore should not include LLVMAnalysis header
llvm/Analysis/ModuleSummaryAnalysis.h

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[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm

Enable using -module-summary with -S
(similarly to what currently can be achieved with opt <input> -o - | llvm-dis).
This is a

[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm

Enable using -module-summary with -S
(similarly to what currently can be achieved with opt <input> -o - | llvm-dis).
This is a recommit of ef9e62469.

Test plan: ninja check-all

Differential revision: https://reviews.llvm.org/D137768

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[ModuleSummaryAnalysis] Use helper methods to check readnone/readonly (NFC)

This makes sure that this code continue working when switching to
the memory attribute.

A caveat here is that onlyReadsMe

[ModuleSummaryAnalysis] Use helper methods to check readnone/readonly (NFC)

This makes sure that this code continue working when switching to
the memory attribute.

A caveat here is that onlyReadsMemory() will also true for readnone.
To be conservative, I'm explicitly excluding that case here.

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[WPD] Use new llvm.public.type.test intrinsic for potentially publicly visible classes

Turning on opaque pointers has uncovered an issue with WPD where we currently pattern match away `assume(type.t

[WPD] Use new llvm.public.type.test intrinsic for potentially publicly visible classes

Turning on opaque pointers has uncovered an issue with WPD where we currently pattern match away `assume(type.test)` in WPD so that a later LTT doesn't resolve the type test to undef and introduce an `assume(false)`. The pattern matching can fail in cases where we transform two `assume(type.test)`s into `assume(phi(type.test.1, type.test.2))`.

Currently we create `assume(type.test)` for all virtual calls that might be devirtualized. This is to support `-Wl,--lto-whole-program-visibility`.

To prevent this, all virtual calls that may not be in the same LTO module instead use a new `llvm.public.type.test` intrinsic in place of the `llvm.type.test`. Then when we know if `-Wl,--lto-whole-program-visibility` is passed or not, we can either replace all `llvm.public.type.test` with `llvm.type.test`, or replace all `llvm.public.type.test` with `true`. This prevents WPD from trying to pattern match away `assume(type.test)` for public virtual calls when failing the pattern matching will result in miscompiles.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D128955

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[ThinLTO] Support aliased GlobalIFunc

Fixes https://github.com/llvm/llvm-project/issues/56290: when an ifunc is
aliased in LTO, clang will attempt to create an alias summary; however, as ifunc
is no

[ThinLTO] Support aliased GlobalIFunc

Fixes https://github.com/llvm/llvm-project/issues/56290: when an ifunc is
aliased in LTO, clang will attempt to create an alias summary; however, as ifunc
is not included in the module summary, doing so will lead to crash.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D129009

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[Analysis] Qualify auto variables in for loops (NFC)

[llvm] Don't use Optional::getValue (NFC)

[LTO] Initialize canAutoHide() using canBeOmittedFromSymbolTable()

Per discussion on
https://reviews.llvm.org/D59709#inline-1148734, this seems like the
right course of action. `canBeOmittedFromSymb

[LTO] Initialize canAutoHide() using canBeOmittedFromSymbolTable()

Per discussion on
https://reviews.llvm.org/D59709#inline-1148734, this seems like the
right course of action. `canBeOmittedFromSymbolTable()` subsumes and
generalizes the previous logic. In addition to handling `linkonce_odr`
`unnamed_addr` globals, we now also internalize `linkonce_odr` +
`local_unnamed_addr` constants.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D120173

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Cleanup includes: LLVMAnalysis

Number of lines output by preprocessor:
before: 1065940348
after: 1065307662

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

Cleanup includes: LLVMAnalysis

Number of lines output by preprocessor:
before: 1065940348
after: 1065307662

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D120659

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[LTO][WPD] Simplify mustBeUnreachableFunction and test after D115492

An well-formed IR function definition must have an entry basic block and
a well-formed IR basic block must have one terminator so

[LTO][WPD] Simplify mustBeUnreachableFunction and test after D115492

An well-formed IR function definition must have an entry basic block and
a well-formed IR basic block must have one terminator so the emptiness
check can be simplified.
Also simplify the test a bit.

Reviewed By: luna

Differential Revision: https://reviews.llvm.org/D115780

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[LTO] Ignore unreachable virtual functions in WPD in hybrid LTO.

Differential Revision: https://reviews.llvm.org/D115492

[IR][NFC] Rename getBaseObject to getAliaseeObject

To better reflect the meaning of the now-disambiguated {GlobalValue,
GlobalAlias}::getBaseObject after breaking off GlobalIFunc::getResolverFunctio

[IR][NFC] Rename getBaseObject to getAliaseeObject

To better reflect the meaning of the now-disambiguated {GlobalValue,
GlobalAlias}::getBaseObject after breaking off GlobalIFunc::getResolverFunction
(D109792), the function is renamed to getAliaseeObject.

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