[nfc][thinlto] remove unnecessary return from `renameModuleForThinLTO` (#121851)

Same goes for `FunctionImportGlobalProcessing::run`.

The return value was used, but it was always `false`.

[NFCI]Remove EntryCount from FunctionSummary and clean up surrounding synthetic count passes. (#107471)

The primary motivation is to remove `EntryCount` from `FunctionSummary`.
This frees 8 bytes o

[NFCI]Remove EntryCount from FunctionSummary and clean up surrounding synthetic count passes. (#107471)

The primary motivation is to remove `EntryCount` from `FunctionSummary`.
This frees 8 bytes out of `sizeof(FunctionSummary)` (136 bytes as of
https://github.com/llvm/llvm-project/commit/64498c54831bed9cf069e0923b9b73678c6451d8).

While I'm at it, this PR clean up {SummaryBasedOptimizations,
SyntheticCountsPropagation} since they were not used and there are no
plans to further invest on them.

With this patch, bitcode writer writes a placeholder 0 at the byte
offset of `EntryCount` and bitcode reader can parse the function entry
count at the correct byte offset. Added a TODO to stop writing
`EntryCount` and bump bitcode version

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[Transforms] Qualify auto in range-based for loops (NFC)

Identified with readability-qualified-auto.

Add switch to use "source_filename" instead of a hash ID for globally promoted local

During LTO a local promoted to a global gets a unique suffix based on
a hash of the module IR. This means that ch

Add switch to use "source_filename" instead of a hash ID for globally promoted local

During LTO a local promoted to a global gets a unique suffix based on
a hash of the module IR. This means that changes in the local's module
can affect the contents in another module that imported it (because the name
of the imported promoted local is changed, but that doesn't reflect a
real change in the importing module). So any tool that's
validating changes to the importing module will see a superficial change.

Instead of using the module hash, we can use the "source_filename" if it
exists to generate a unique identifier that doesn't change due to LTO
shenanigans.

Differential Revision: https://reviews.llvm.org/D128863

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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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Cleanup includes: TransformsUtils

Estimation on the impact on preprocessor output:
before: 1065307662
after: 1064800684

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

Cleanup includes: TransformsUtils

Estimation on the impact on preprocessor output:
before: 1065307662
after: 1064800684

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D120741

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[ThinLTO] Respect ClearDSOLocalOnDeclarations for unimported functions

D74751 added `ClearDSOLocalOnDeclarations` and dropped dso_local for
isDeclarationForLinker `GlobalValue`s. It missed a case fo

[ThinLTO] Respect ClearDSOLocalOnDeclarations for unimported functions

D74751 added `ClearDSOLocalOnDeclarations` and dropped dso_local for
isDeclarationForLinker `GlobalValue`s. It missed a case for imported
declarations (`doImportAsDefinition` is false while `isPerformingImport` is
true). This can lead to a linker error for a default visibility symbol in
`ld.lld -shared`.

When `ClearDSOLocalOnDeclarations` is true, we check
`isPerformingImport() && !doImportAsDefinition(&GV)` along with
`GV.isDeclarationForLinker()`. The new condition checks an imported declaration.

This patch fixes a `LLVMPolly.so` link error using a trunk clang -DLLVM_ENABLE_LTO=Thin.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D104986

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[LTO] Perform DSOLocal propagation in combined index

Perform DSOLocal propagation within summary list of every GV. This
avoids the repeated query of this information during function
importing.

Diff

[LTO] Perform DSOLocal propagation in combined index

Perform DSOLocal propagation within summary list of every GV. This
avoids the repeated query of this information during function
importing.

Differential Revision: https://reviews.llvm.org/D96398

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[ThinLTO] Drop dso_local if a GlobalVariable satisfies isDeclarationForLinker()

dso_local leads to direct access even if the definition is not within this compilation unit (it is
still in the same l

[ThinLTO] Drop dso_local if a GlobalVariable satisfies isDeclarationForLinker()

dso_local leads to direct access even if the definition is not within this compilation unit (it is
still in the same linkage unit). On ELF, such a relocation (e.g. R_X86_64_PC32) referencing a
STB_GLOBAL STV_DEFAULT object can cause a linker error in a -shared link.

If the linkage is changed to available_externally, the dso_local flag should be dropped, so that no
direct access will be generated.

The current behavior is benign, because -fpic does not assume dso_local
(clang/lib/CodeGen/CodeGenModule.cpp:shouldAssumeDSOLocal).
If we do that for -fno-semantic-interposition (D73865), there will be an
R_X86_64_PC32 linker error without this patch.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D74751

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[ThinLTO] Fix importing of writeonly variables in distributed ThinLTO

Summary:
D69561/dde5893 enabled importing of readonly variables with references,
however, it introduced a bug relating to import

[ThinLTO] Fix importing of writeonly variables in distributed ThinLTO

Summary:
D69561/dde5893 enabled importing of readonly variables with references,
however, it introduced a bug relating to importing/internalization of
writeonly variables with references.

A fix for this was added in D70006/7f92d66. But this didn't work in
distributed ThinLTO mode. The reason is that the fix (importing the
writeonly var with a zeroinitializer) was only applied when there were
references on the writeonly var summary. In distributed ThinLTO mode,
where we only have a small slice of the index, we will not have the
references on the importing side if we are not importing those
referenced values. Rather than changing this handshaking (which will
require a lot of other changes, since that's how we know what to import
in the distributed backend clang invocation), we can simply always give
the writeonly variable a zero initializer.

Reviewers: evgeny777, steven_wu

Subscribers: mehdi_amini, inglorion, hiraditya, dexonsmith, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70977

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[ThinLTO] Avoid extra index lookup during promotion

Summary:
Pass down the already accessed ValueInfo to shouldPromoteLocalToGlobal,
to avoid an unnecessary extra index lookup.

Add some assertion c

[ThinLTO] Avoid extra index lookup during promotion

Summary:
Pass down the already accessed ValueInfo to shouldPromoteLocalToGlobal,
to avoid an unnecessary extra index lookup.

Add some assertion checking to confirm we have a non-empty VI when
expected.

Also some misc cleanup, merging the two versions of
doImportAsDefinition, since one was only called by the other, and
unnecessarily passed in a member variable.

Reviewers: steven_wu, pcc, evgeny777

Reviewed By: evgeny777

Subscribers: mehdi_amini, inglorion, hiraditya, dexonsmith, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70337

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[ThinLTO] Promotion handling cleanup (NFC)

Summary:
Clean up the code that does GV promotion in the ThinLTO backends.

Specifically, we don't need to check whether we are importing since that
is alr

[ThinLTO] Promotion handling cleanup (NFC)

Summary:
Clean up the code that does GV promotion in the ThinLTO backends.

Specifically, we don't need to check whether we are importing since that
is already checked and handled correctly in shouldPromoteLocalToGlobal.
Simply call shouldPromoteLocalToGlobal, and if it returns true we are
guaranteed that we are promoting, whether or not we are importing (or in
the exporting module). This also makes the handling in getName()
consistent with that in getLinkage(), which checks the DoPromote parameter
regardless of whether we are importing or exporting.

Reviewers: steven_wu, pcc, evgeny777

Subscribers: mehdi_amini, inglorion, hiraditya, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70327

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Recommit "[ThinLTO] Add correctness check for RO/WO variable import"

ValueInfo has user-defined 'operator bool' which allows incorrect implicit conversion
to GlobalValue::GUID (which is unsigned lon

Recommit "[ThinLTO] Add correctness check for RO/WO variable import"

ValueInfo has user-defined 'operator bool' which allows incorrect implicit conversion
to GlobalValue::GUID (which is unsigned long). This causes bugs which are hard to
track and should be removed in future.

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Revert "[ThinLTO] Add correctness check for RO/WO variable import"

This reverts commit a2292cc537b561416c21e8d4017715d652c144cc. Breaks
clang selfhost w/ThinLTO.

[ThinLTO] Add correctness check for RO/WO variable import

This patch adds an assertion check for exported read/write-only
variables to be also in import list for module. If they aren't
we may face l

[ThinLTO] Add correctness check for RO/WO variable import

This patch adds an assertion check for exported read/write-only
variables to be also in import list for module. If they aren't
we may face linker errors, because read/write-only variables are
internalized in their source modules. The patch also changes
export lists to store ValueInfo instead of GUID for performance
considerations.

Differential revision: https://reviews.llvm.org/D70128

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[ThinLTO] Fix bug when importing writeonly variables

Patch enables import of write-only variables with non-trivial initializers
to fix linker errors. Initializers of imported variables are converted

[ThinLTO] Fix bug when importing writeonly variables

Patch enables import of write-only variables with non-trivial initializers
to fix linker errors. Initializers of imported variables are converted to
'zeroinitializer' to avoid promotion of referenced objects.

Differential revision: https://reviews.llvm.org/D70006

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[ThinLTO] Import readonly vars with refs

Patch allows importing declarations of functions and variables, referenced
by the initializer of some other readonly variable.
Differential revision: https:/

[ThinLTO] Import readonly vars with refs

Patch allows importing declarations of functions and variables, referenced
by the initializer of some other readonly variable.
Differential revision: https://reviews.llvm.org/D69561

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Recommit "[ThinLTO] Handle GUID collision in import global processing""

This recommits cc0b9647b76178bc3869bbfff80535ad86366472 which was
reverted in d39d1a2f87aca3cfabe58ecfa5146879baa70096.

I add

Recommit "[ThinLTO] Handle GUID collision in import global processing""

This recommits cc0b9647b76178bc3869bbfff80535ad86366472 which was
reverted in d39d1a2f87aca3cfabe58ecfa5146879baa70096.

I added a fix for an issue found when testing via distributed ThinLTO,
and added a test case for that failure.

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Revert "[LLD][ThinLTO] Handle GUID collision in import global processing"

This reverts commit cc0b9647b76178bc3869bbfff80535ad86366472.

The commit is causing a failure in internal testing. Will rec

Revert "[LLD][ThinLTO] Handle GUID collision in import global processing"

This reverts commit cc0b9647b76178bc3869bbfff80535ad86366472.

The commit is causing a failure in internal testing. Will recommit with
a fix later.

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[LLD][ThinLTO] Handle GUID collision in import global processing

Summary:
If there are a GUID collision between two globals checking the
summarylist from the import index to make assumption can be d

[LLD][ThinLTO] Handle GUID collision in import global processing

Summary:
If there are a GUID collision between two globals checking the
summarylist from the import index to make assumption can be dangerous.

Do not assume that a GlobalValue that has a GlobalVarSummary
actually is a GlobalVariable as it can be another GlobalValue with
the same GUID that the summary is connected to.

Patch by Joel Klinghed (the_jk@opera.com)

Reviewers: evgeny777, tejohnson

Reviewed By: tejohnson

Subscribers: tejohnson, dblaikie, MaskRay, mehdi_amini, inglorion, hiraditya, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67322

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FunctionImportGlobalProcessing::processGlobalForThinLTO - silence static analyzer dyn_cast<FunctionSummary> null dereference warning. NFCI.

The static analyzer is warning about a potential null dere

FunctionImportGlobalProcessing::processGlobalForThinLTO - silence static analyzer dyn_cast<FunctionSummary> null dereference warning. NFCI.

The static analyzer is warning about a potential null dereference, but we should be able to use cast<FunctionSummary> directly and if not assert will fire for us.

llvm-svn: 373097

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[ThinLTO] Attempt to recommit r365188 after alignment fix

llvm-svn: 365215

Reverted r365188 due to alignment problems on i686-android

llvm-svn: 365206

[ThinLTO] Attempt to recommit r365040 after caching fix

It's possible that some function can load and store the same
variable using the same constant expression:

store %Derived* @foo, %Derived** bi

[ThinLTO] Attempt to recommit r365040 after caching fix

It's possible that some function can load and store the same
variable using the same constant expression:

store %Derived* @foo, %Derived** bitcast (%Base** @bar to %Derived**)
%42 = load %Derived*, %Derived** bitcast (%Base** @bar to %Derived**)

The bitcast expression was mistakenly cached while processing loads,
and never examined later when processing store. This caused @bar to
be mistakenly treated as read-only variable. See load-store-caching.ll.

llvm-svn: 365188

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Revert [ThinLTO] Optimize writeonly globals out

This reverts r365040 (git commit 5cacb914758c7f436b47c8362100f10cef14bbc4)

Speculatively reverting, since this appears to have broken check-lld on
Li

Revert [ThinLTO] Optimize writeonly globals out

This reverts r365040 (git commit 5cacb914758c7f436b47c8362100f10cef14bbc4)

Speculatively reverting, since this appears to have broken check-lld on
Linux. Partial analysis in https://crbug.com/981168.

llvm-svn: 365097

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