[InstrProfiling] No runtime registration for ELF, COFF, Mach-O and XCOFF (#77225)

Whether runtime registration is needed is not dependent on the OS but
the file format. For ELF, COFF, Mach-O or XCO

[InstrProfiling] No runtime registration for ELF, COFF, Mach-O and XCOFF (#77225)

Whether runtime registration is needed is not dependent on the OS but
the file format. For ELF, COFF, Mach-O or XCOFF, we can always use the
linker support. This is important for baremetal platforms such as RTOS
and UEFI platforms where there is no OS but we still don't want to use
runtime registration and rely on linker support instead.

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Reland [InstrProf][X86] Mark non-directly accessed globals as large (#74778)

We'd like to make various instrprof globals large to make them not
contribute to relocation pressure since there are no d

Reland [InstrProf][X86] Mark non-directly accessed globals as large (#74778)

We'd like to make various instrprof globals large to make them not
contribute to relocation pressure since there are no direct accesses
to them in the module.

Similar to what was done for asan_globals in #74514.

This affects the __llvm_prf_vals, __llvm_prf_vnds, and __llvm_prf_names
sections.

The reland fixes platform.ll.

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[PGO][InstrProf][test] Convert to opaque pointers and fix some stale tests

[test] Migrate legacy InstrProfiling tests to new PM

[PS5] Use linker scripting to find profiling data, like PS4

[AIX][PGO] Enable linux style PGO on AIX

This patch switches the PGO implementation on AIX from using the runtime
registration-based section tracking to the __start_SECNAME/__stop_SECNAME
based. In

[AIX][PGO] Enable linux style PGO on AIX

This patch switches the PGO implementation on AIX from using the runtime
registration-based section tracking to the __start_SECNAME/__stop_SECNAME
based. In order to enable the recognition of __start_SECNAME/__stop_SECNAME
symbols in the AIX linker, the -bdbg:namedsects:ss needs to be used.

Reviewed By: jsji, MaskRay, davidxl

Differential Revision: https://reviews.llvm.org/D124857

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[InstrProfiling] Add AIX triple to platform test

We found that AIX was not covered in most of the InstrProfiling tests.
So we are trying to enable the tests gradually.

This is to add AIX triple to

[InstrProfiling] Add AIX triple to platform test

We found that AIX was not covered in most of the InstrProfiling tests.
So we are trying to enable the tests gradually.

This is to add AIX triple to platform tests to make sure the
registrations are OK.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D108490

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Revert "[InstrProfiling] Make COFF use the ELF comdat scheme (drop link.exe compatibility)"

This reverts commit fbb8e772ec501a1b71643db90e9c6445e17d7cac.

Accidentally pushed.

[InstrProfiling] Make COFF use the ELF comdat scheme (drop link.exe compatibility)

The COFF specific `DataReferencedByCode` complexity (D103372 D103717) is due to
a link.exe limitation: an external

[InstrProfiling] Make COFF use the ELF comdat scheme (drop link.exe compatibility)

The COFF specific `DataReferencedByCode` complexity (D103372 D103717) is due to
a link.exe limitation: an external symbol in IMAGE_COMDAT_SELECT_ASSOCIATIVE is
not really dropped, so it can cause duplicate definition error.

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[InstrProfiling] If no value profiling, make data variable private and (for Windows) use one comdat

`__profd_*` variables are referenced by code only when value profiling is
enabled. If disabled (e.

[InstrProfiling] If no value profiling, make data variable private and (for Windows) use one comdat

`__profd_*` variables are referenced by code only when value profiling is
enabled. If disabled (e.g. default -fprofile-instr-generate), the symbols just
waste space on ELF/Mach-O. We change the comdat symbol from `__profd_*` to
`__profc_*` because an internal symbol does not provide deduplication features
on COFF. The choice doesn't matter on ELF.

(In -DLLVM_BUILD_INSTRUMENTED_COVERAGE=on build, there is now no `__profd_*` symbols.)

On Windows this enables further optimization. We are no longer affected by the
link.exe limitation: an external symbol in IMAGE_COMDAT_SELECT_ASSOCIATIVE can
cause duplicate definition error.
https://lists.llvm.org/pipermail/llvm-dev/2021-May/150758.html
We can thus use llvm.compiler.used instead of llvm.used like ELF (D97585).
This avoids many `/INCLUDE:` directives in `.drectve`.

Here is rnk's measurement for Chrome:
```
This reduced object file size of base_unittests.exe, compiled with coverage, optimizations, and gmlt debug info by 10%:

#BEFORE

$ find . -iname '*.obj' | xargs du -b | awk '{ sum += $1 } END { print sum}'
1047758867

$ du -cksh base_unittests.exe
82M base_unittests.exe
82M total

# AFTER

$ find . -iname '*.obj' | xargs du -b | awk '{ sum += $1 } END { print sum}'
937886499

$ du -cksh base_unittests.exe
78M base_unittests.exe
78M total
```

The change is NFC for Mach-O.

Reviewed By: davidxl, rnk

Differential Revision: https://reviews.llvm.org/D103372

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Revert "[InstrProfiling] If no value profiling, make data variable private and (for Windows) use one comdat"

This reverts commit a14fc749aab2c8e1a45d19d512255ebfc69357c3.
Breaks check-profile on mac

Revert "[InstrProfiling] If no value profiling, make data variable private and (for Windows) use one comdat"

This reverts commit a14fc749aab2c8e1a45d19d512255ebfc69357c3.
Breaks check-profile on macOS. See https://reviews.llvm.org/D103372 for details.

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[InstrProfiling] If no value profiling, make data variable private and (for Windows) use one comdat

`__profd_*` variables are referenced by code only when value profiling is
enabled. If disabled (e.

[InstrProfiling] If no value profiling, make data variable private and (for Windows) use one comdat

`__profd_*` variables are referenced by code only when value profiling is
enabled. If disabled (e.g. default -fprofile-instr-generate), the symbols just
waste space on ELF/Mach-O. We change the comdat symbol from `__profd_*` to
`__profc_*` because an internal symbol does not provide deduplication features
on COFF. The choice doesn't matter on ELF.

(In -DLLVM_BUILD_INSTRUMENTED_COVERAGE=on build, there is now no `__profd_*` symbols.)

On Windows this enables further optimization. We are no longer affected by the
link.exe limitation: an external symbol in IMAGE_COMDAT_SELECT_ASSOCIATIVE can
cause duplicate definition error.
https://lists.llvm.org/pipermail/llvm-dev/2021-May/150758.html
We can thus use llvm.compiler.used instead of llvm.used like ELF (D97585).
This avoids many `/INCLUDE:` directives in `.drectve`.

Here is rnk's measurement for Chrome:
```
This reduced object file size of base_unittests.exe, compiled with coverage, optimizations, and gmlt debug info by 10%:

#BEFORE

$ find . -iname '*.obj' | xargs du -b | awk '{ sum += $1 } END { print sum}'
1047758867

$ du -cksh base_unittests.exe
82M base_unittests.exe
82M total

# AFTER

$ find . -iname '*.obj' | xargs du -b | awk '{ sum += $1 } END { print sum}'
937886499

$ du -cksh base_unittests.exe
78M base_unittests.exe
78M total
```

Reviewed By: davidxl, rnk

Differential Revision: https://reviews.llvm.org/D103372

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[InstrProfiling] Delete linkage/visibility toggling for Windows

The linkage/visibility of `__profn_*` variables are derived
from the profiled functions.

extern_weak => linkonce
available_ex

[InstrProfiling] Delete linkage/visibility toggling for Windows

The linkage/visibility of `__profn_*` variables are derived
from the profiled functions.

extern_weak => linkonce
available_externally => linkonce_odr
internal => private
extern => private
_ => unchanged

The linkage/visibility of `__profc_*`/`__profd_*` variables are derived from
`__profn_*` with linkage/visibility wrestling for Windows.

The changes can be folded to the following without changing semantics.

```
if (TT.isOSBinFormatCOFF() && !NeedComdat) {
Linkage = GlobalValue::InternalLinkage;
Visibility = GlobalValue::DefaultVisibility;
}
```

That said, I think we can just delete the code block.

An extern/internal function will now use private `__profc_*`/`__profd_*`
variables, instead of internal ones. This saves some symbol table entries.

A non-comdat {linkonce,weak}_odr function will now use hidden external
`__profc_*`/`__profd_*` variables instead of internal ones. There is potential
object file size increase because such symbols need `/INCLUDE:` directives.
However such non-comdat functions are rare (note that non-comdat weak
definitions don't prevent duplicate definition error).

The behavior changes match ELF.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D103355

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[InstrProfiling][test] Improve tests

[InstrProfiling][test] Fix stale tests

* Change linkage/visibility of __profn_ variables to match the reality
* alwaysinline.ll: Add "EnableValueProfiling", otherwise it doesn't test available_exter

[InstrProfiling][test] Fix stale tests

* Change linkage/visibility of __profn_ variables to match the reality
* alwaysinline.ll: Add "EnableValueProfiling", otherwise it doesn't test available_externally alwaysinline.
* Delete PR23499.ll - covered by other comdat tests.

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[InstrProfiling] Use ELF section groups for counters, data and values

__start_/__stop_ references retain C identifier name sections such as
__llvm_prf_*. Putting these into a section group disables

[InstrProfiling] Use ELF section groups for counters, data and values

__start_/__stop_ references retain C identifier name sections such as
__llvm_prf_*. Putting these into a section group disables this logic.

The ELF section group semantics ensures that group members are retained
or discarded as a unit. When a function symbol is discarded, this allows
allows linker to discard counters, data and values associated with that
function symbol as well.

Note that `noduplicates` COMDAT is lowered to zero-flag section group in
ELF. We only set this for functions that aren't already in a COMDAT and
for those that don't have available_externally linkage since we already
use regular COMDAT groups for those.

Differential Revision: https://reviews.llvm.org/D96757

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Revert "[InstrProfiling] Use ELF section groups for counters, data and values"

This reverts commits:
5ca21175e09fc7fb7dcaee9ebd6782d122a5688f
97184ab99c46e35ae94f828ee90f5d6af2c47e11

The instrprof-

Revert "[InstrProfiling] Use ELF section groups for counters, data and values"

This reverts commits:
5ca21175e09fc7fb7dcaee9ebd6782d122a5688f
97184ab99c46e35ae94f828ee90f5d6af2c47e11

The instrprof-gc-sections.c is failing on AArch64 LLD bot.

show more ...

[InstrProfiling] Use ELF section groups for counters, data and values

__start_/__stop_ references retain C identifier name sections such as
__llvm_prf_*. Putting these into a section group disables

[InstrProfiling] Use ELF section groups for counters, data and values

__start_/__stop_ references retain C identifier name sections such as
__llvm_prf_*. Putting these into a section group disables this logic.

The ELF section group semantics ensures that group members are retained
or discarded as a unit. When a function symbol is discarded, this allows
allows linker to discard counters, data and values associated with that
function symbol as well.

Note that `noduplicates` COMDAT is lowered to zero-flag section group in
ELF. We only set this for functions that aren't already in a COMDAT and
for those that don't have available_externally linkage since we already
use regular COMDAT groups for those.

Differential Revision: https://reviews.llvm.org/D96757

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[profile] Solaris ld supports __start___llvm_prof_data etc. labels

Currently, many profiling tests on Solaris FAIL like

Command Output (stderr):
--
Undefined first refer

[profile] Solaris ld supports __start___llvm_prof_data etc. labels

Currently, many profiling tests on Solaris FAIL like

Command Output (stderr):
--
Undefined first referenced
symbol in file
__llvm_profile_register_names_function /tmp/lit_tmp_Nqu4eh/infinite_loop-9dc638.o
__llvm_profile_register_function /tmp/lit_tmp_Nqu4eh/infinite_loop-9dc638.o

Solaris 11.4 ld supports the non-standard GNU ld extension of adding
__start_SECNAME and __stop_SECNAME labels to sections whose names are valid
as C identifiers. Given that we already use Solaris 11.4-only features
like ld -z gnu-version-script-compat and fully working .preinit_array
support in compiler-rt, we don't need to worry about older versions of
Solaris ld.

The patch documents that support (although the comment in
lib/Transforms/Instrumentation/InstrProfiling.cpp
(needsRuntimeRegistrationOfSectionRange) is quite cryptic what it's
actually about), and adapts the affected testcase not to expect the
alternativeq __llvm_profile_register_functions and __llvm_profile_init.
It fixes all affected tests.

Tested on amd64-pc-solaris2.11.

Differential Revision: https://reviews.llvm.org/D41111

llvm-svn: 363984

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[InstrProf] Implement static profdata registration

Summary:
The motivating use case is eliminating duplicate profile data registered
for the same inline function in two object files. Before this cha

[InstrProf] Implement static profdata registration

Summary:
The motivating use case is eliminating duplicate profile data registered
for the same inline function in two object files. Before this change,
users would observe multiple symbol definition errors with VC link, but
links with LLD would succeed.

Users (Mozilla) have reported that PGO works well with clang-cl and LLD,
but when using LLD without this static registration, we would get into a
"relocation against a discarded section" situation. I'm not sure what
happens in that situation, but I suspect that duplicate, unused profile
information was retained. If so, this change will reduce the size of
such binaries with LLD.

Now, Windows uses static registration and is in line with all the other
platforms.

Reviewers: davidxl, wmi, inglorion, void, calixte

Subscribers: mgorny, krytarowski, eraman, fedor.sergeev, hiraditya, #sanitizers, dmajor, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D57929

llvm-svn: 353547

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[InstrProf] Don't register __llvm_profile_runtime_user

Refactor some FileCheck prefixes while I'm at it.

Fixes PR38340

llvm-svn: 338172

Re-apply "[profiling] Remove dead profile name vars after emitting name data"

This reverts 295092 (re-applies 295084), with a fix for dangling
references from the array of coverage names passed down

Re-apply "[profiling] Remove dead profile name vars after emitting name data"

This reverts 295092 (re-applies 295084), with a fix for dangling
references from the array of coverage names passed down from frontends.

I missed this in my initial testing because I only checked test/Profile,
and not test/CoverageMapping as well.

Original commit message:

The profile name variables passed to counter increment intrinsics are dead
after we emit the finalized name data in __llvm_prf_nm. However, we neglect to
erase these name variables. This causes huge size increases in the
__TEXT,__const section as well as slowdowns when linker dead stripping is
disabled. Some affected projects are so massive that they fail to link on
Darwin, because only the small code model is supported.

Fix the issue by throwing away the name constants as soon as we're done with
them.

Differential Revision: https://reviews.llvm.org/D29921

llvm-svn: 295099

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Revert "[profiling] Remove dead profile name vars after emitting name data"

This reverts commit r295084. There is a test failure on:

http://lab.llvm.org:8011/builders/clang-atom-d525-fedora-rel/bui

Revert "[profiling] Remove dead profile name vars after emitting name data"

This reverts commit r295084. There is a test failure on:

http://lab.llvm.org:8011/builders/clang-atom-d525-fedora-rel/builds/2620/

llvm-svn: 295092

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[profiling] Remove dead profile name vars after emitting name data

The profile name variables passed to counter increment intrinsics are
dead after we emit the finalized name data in __llvm_prf_nm.

[profiling] Remove dead profile name vars after emitting name data

The profile name variables passed to counter increment intrinsics are
dead after we emit the finalized name data in __llvm_prf_nm. However, we
neglect to erase these name variables. This causes huge size increases
in the __TEXT,__const section as well as slowdowns when linker dead
stripping is disabled. Some affected projects are so massive that they
fail to link on Darwin, because only the small code model is supported.

Fix the issue by throwing away the name constants as soon as we're done
with them.

Differential Revision: https://reviews.llvm.org/D29921

llvm-svn: 295084

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[InstrProf] Add support for dead_strip+live_support functionality

On Darwin, marking a section as "regular,live_support" means that a
symbol in the section should only be kept live if it has a refer

[InstrProf] Add support for dead_strip+live_support functionality

On Darwin, marking a section as "regular,live_support" means that a
symbol in the section should only be kept live if it has a reference to
something that is live. Otherwise, the linker is free to dead-strip it.

Turn this functionality on for the __llvm_prf_data section.

This means that counters and data associated with dead functions will be
removed from dead-stripped binaries. This will result in smaller
profiles and binaries, and should speed up profile collection.

Tested with check-profile, llvm-lit test/tools/llvm-{cov,profdata}, and
check-llvm.

Differential Revision: https://reviews.llvm.org/D25456

llvm-svn: 283947

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