[llvm-profdata] Do not create numerical strings for MD5 function names read from a Sample Profile. (#66164)

This is phase 2 of the MD5 refactoring on Sample Profile following
https://reviews.llvm.o

[llvm-profdata] Do not create numerical strings for MD5 function names read from a Sample Profile. (#66164)

This is phase 2 of the MD5 refactoring on Sample Profile following
https://reviews.llvm.org/D147740

In previous implementation, when a MD5 Sample Profile is read, the
reader first converts the MD5 values to strings, and then create a
StringRef as if the numerical strings are regular function names, and
later on IPO transformation passes perform string comparison over these
numerical strings for profile matching. This is inefficient since it
causes many small heap allocations.
In this patch I created a class `ProfileFuncRef` that is similar to
`StringRef` but it can represent a hash value directly without any
conversion, and it will be more efficient (I will attach some benchmark
results later) when being used in associative containers.

ProfileFuncRef guarantees the same function name in string form or in
MD5 form has the same hash value, which also fix a few issue in IPO
passes where function matching/lookup only check for function name
string, while returns a no-match if the profile is MD5.

When testing on an internal large profile (> 1 GB, with more than 10
million functions), the full profile load time is reduced from 28 sec to
25 sec in average, and reading function offset table from 0.78s to 0.7s

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[llvm-profdata] Deprecate Compact Binary Sample Profile Format

Remove support for compact binary sample profile format

Reviewed By: davidxl, wenlei

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

[llvm-profdata] Deprecate Compact Binary Sample Profile Format

Remove support for compact binary sample profile format

Reviewed By: davidxl, wenlei

Differential Revision: https://reviews.llvm.org/D149400

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[NFC][Profile] Access profile through VirtualFileSystem

Make the access to profile data going through virtual file system so the
inputs can be remapped. In the context of the caching, it can make su

[NFC][Profile] Access profile through VirtualFileSystem

Make the access to profile data going through virtual file system so the
inputs can be remapped. In the context of the caching, it can make sure
we capture the inputs and provided an immutable input as profile data.

Reviewed By: akyrtzi, benlangmuir

Differential Revision: https://reviews.llvm.org/D139052

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[NFC] ProfileSummary: const most of the fields.

This simplifies readability / maintainability.

[CSSPGO] Split context string to deduplicate function name used in the context.

Currently context strings contain a lot of duplicated function names and that significantly increase the profile size.

[CSSPGO] Split context string to deduplicate function name used in the context.

Currently context strings contain a lot of duplicated function names and that significantly increase the profile size. This change split the context into a series of {name, offset, discriminator} tuples so function names used in the context can be replaced by the index into the name table and that significantly reduce the size consumed by context.

A follow-up improvement made in the compiler and profiling tools is to avoid reconstructing full context strings which is time- and memory- consuming. Instead a context vector of `StringRef` is adopted to represent the full context in all scenarios. As a result, the previous prevalent profile map which was implemented as a `StringRef` is now engineered as an unordered map keyed by `SampleContext`. `SampleContext` is reshaped to using an `ArrayRef` to represent a full context for CS profile. For non-CS profile, it falls back to use `StringRef` to represent a contextless function name. Both the `ArrayRef` and `StringRef` objects are underpinned by real array and string objects that are stored in producer buffers. For compiler, they are maintained by the sample reader. For llvm-profgen, they are maintained in `ProfiledBinary` and `ProfileGenerator`. Full context strings can be generated only in those cases of debugging and printing.

When it comes to profile format, nothing has changed to the text format, though internally CS context is implemented as a vector. Extbinary format is only changed for CS profile, with an additional `SecCSNameTable` section which stores all full contexts logically in the form of `vector<int>`, which each element as an offset points to `SecNameTable`. All occurrences of contexts elsewhere are redirected to using the offset of `SecCSNameTable`.

Testing
This is no-diff change in terms of code quality and profile content (for text profile).

For our internal large service (aka ads), the profile generation is cut to half, with a 20x smaller string-based extbinary format generated.

The compile time of ads is dropped by 25%.

Differential Revision: https://reviews.llvm.org/D107299

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[SampleFDO] New hierarchical discriminator for FS SampleFDO (llvm-profdata part)

This patch was split from https://reviews.llvm.org/D102246
[SampleFDO] New hierarchical discriminator for Flow Sensit

[SampleFDO] New hierarchical discriminator for FS SampleFDO (llvm-profdata part)

This patch was split from https://reviews.llvm.org/D102246
[SampleFDO] New hierarchical discriminator for Flow Sensitive SampleFDO
This is for llvm-profdata part of change. It sets the bit masks for the
profile reader in llvm-profdata. Also add an internal option
"-fs-discriminator-pass" for show and merge command to process the profile
offline.

This patch also moved setDiscriminatorMaskedBitFrom() to
SampleProfileReader::create() to simplify the interface.

Differential Revision: https://reviews.llvm.org/D103550

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[SampleFDO] New hierarchical discriminator for FS SampleFDO (ProfileData part)

This patch was split from https://reviews.llvm.org/D102246
[SampleFDO] New hierarchical discriminator for Flow Sensitiv

[SampleFDO] New hierarchical discriminator for FS SampleFDO (ProfileData part)

This patch was split from https://reviews.llvm.org/D102246
[SampleFDO] New hierarchical discriminator for Flow Sensitive SampleFDO
This is mainly for ProfileData part of change. It will load
FS Profile when such profile is detected. For an extbinary format profile,
create_llvm_prof tool will add a flag to profile summary section.
For other format profiles, the users need to use an internal option
(-profile-isfs) to tell the compiler that the profile uses FS discriminators.

This patch also simplified the bit API used by FS discriminators.

Differential Revision: https://reviews.llvm.org/D103041

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[SampleFDO] Support enabling -funique-internal-linkage-name.

now -funique-internal-linkage-name flag is available, and we want to flip
it on by default since it is beneficial to have separate sample

[SampleFDO] Support enabling -funique-internal-linkage-name.

now -funique-internal-linkage-name flag is available, and we want to flip
it on by default since it is beneficial to have separate sample profiles
for different internal symbols with the same name. As a preparation, we
want to avoid regression caused by the flip.

When we flip -funique-internal-linkage-name on, the profile is collected
from binary built without -funique-internal-linkage-name so it has no uniq
suffix, but the IR in the optimized build contains the suffix. This kind of
mismatch may introduce transient regression.

To avoid such mismatch, we introduce a NameTable section flag indicating
whether there is any name in the profile containing uniq suffix. Compiler
will decide whether to keep uniq suffix during name canonicalization
depending on the NameTable section flag. The flag is only available for
extbinary format. For other formats, by default compiler will keep uniq
suffix so they will only experience transient regression when
-funique-internal-linkage-name is just flipped.

Another type of regression is caused by places where we miss to call
getCanonicalFnName. Those places are fixed.

Differential Revision: https://reviews.llvm.org/D96932

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[llvm] [unittests] Remove temporary files after they're not needed

Some LLVM unit tests forget to clean up temporary files and
directories. Introduce RAII classes for cleaning them up.

Refactor the

[llvm] [unittests] Remove temporary files after they're not needed

Some LLVM unit tests forget to clean up temporary files and
directories. Introduce RAII classes for cleaning them up.

Refactor the tests to use those classes.

Differential Revision: https://reviews.llvm.org/D83228

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[SampleFDO] Enhance profile remapping support for searching inline instance
and indirect call promotion candidate.

Profile remapping is a feature to match a function in the module with its
profile i

[SampleFDO] Enhance profile remapping support for searching inline instance
and indirect call promotion candidate.

Profile remapping is a feature to match a function in the module with its
profile in sample profile if the function name and the name in profile look
different but are equivalent using given remapping rules. This is a useful
feature to keep the performance stable by specifying some remapping rules
when sampleFDO targets are going through some large scale function signature
change.

However, currently profile remapping support is only valid for outline
function profile in SampleFDO. It cannot match a callee with an inline
instance profile if they have different but equivalent names. We found
that without the support for inline instance profile, remapping is less
effective for some large scale change.

To add that support, before any remapping lookup happens, all the names
in the profile will be inserted into remapper and the Key to the name
mapping will be recorded in a map called NameMap in the remapper. During
name lookup, a Key will be returned for the given name and it will be used
to extract an equivalent name in the profile from NameMap. So with the help
of the NameMap, we can translate any given name to an equivalent name in
the profile if it exists. Whenever we try to match a name in the module to
a name in the profile, we will try the match with the original name first,
and if it doesn't match, we will use the equivalent name got from remapper
to try the match for another time. In this way, the patch can enhance the
profile remapping support for searching inline instance and searching
indirect call promotion candidate.

In a planned large scale change of int64 type (long long) to int64_t (long),
we found the performance of a google internal benchmark degraded by 2% if
nothing was done. If existing profile remapping was enabled, the performance
degradation dropped to 1.2%. If the profile remapping with the current patch
was enabled, the performance degradation further dropped to 0.14% (Note the
experiment was done before searching indirect call promotion candidate was
added. We hope with the remapping support of searching indirect call promotion
candidate, the degradation can drop to 0% in the end. It will be evaluated
post commit).

Differential Revision: https://reviews.llvm.org/D86332

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[ProfileSummary] Add the PartialProfileRatio field in ProfileSummary metadata.

Summary:
PartialProfileRatio approximately represents the ratio of the number of profile
counters of the program being

[ProfileSummary] Add the PartialProfileRatio field in ProfileSummary metadata.

Summary:
PartialProfileRatio approximately represents the ratio of the number of profile
counters of the program being built to the number of profile counters in the
partial sample profile. It is used to scale the working set size under the
partial sample profile to reflect the size of the program being built and to
improve the working set size heuristics.

This is a split from D79831.

Reviewers: davidxl

Subscribers: eraman, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79951

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Fix a memory link problem in SampleProfTest.cpp.

[ProfileSummary] Add partial profile annotation on IR.

Profile and profile summary are usually read only once and then annotated
on IR. The profile summary metadata on IR should include the value of

[ProfileSummary] Add partial profile annotation on IR.

Profile and profile summary are usually read only once and then annotated
on IR. The profile summary metadata on IR should include the value of the
newly added partial profile flag, so that compilation phase like thinlto
postlink can get the full set of profile information.

Differential Revision: https://reviews.llvm.org/D78310

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[SampleFDO] Port MD5 name table support to extbinary format.

Compbinary format uses MD5 to represent strings in name table. That gives smaller profile without the need of compression/decompression w

[SampleFDO] Port MD5 name table support to extbinary format.

Compbinary format uses MD5 to represent strings in name table. That gives smaller profile without the need of compression/decompression when writing/reading the profile. The patch adds the support in extbinary format. It is off by default but user can choose to enable it.

Note the feature of using MD5 in name table can bring very small chance of name conflict leading to profile mismatch. Besides, profile using the feature won't have the profile remapping support.

Differential Revision: https://reviews.llvm.org/D76255

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Avoid including FileSystem.h from MemoryBuffer.h

Lots of headers pass around MemoryBuffer objects, but very few open
them. Let those that do include FileSystem.h.

Saves ~250 includes of Chrono.h &

Avoid including FileSystem.h from MemoryBuffer.h

Lots of headers pass around MemoryBuffer objects, but very few open
them. Let those that do include FileSystem.h.

Saves ~250 includes of Chrono.h & FileSystem.h:

$ diff -u thedeps-before.txt thedeps-after.txt | grep '^[-+] ' | sort | uniq -c | sort -nr
254 - ../llvm/include/llvm/Support/FileSystem.h
253 - ../llvm/include/llvm/Support/Chrono.h
237 - ../llvm/include/llvm/Support/NativeFormatting.h
237 - ../llvm/include/llvm/Support/FormatProviders.h
192 - ../llvm/include/llvm/ADT/StringSwitch.h
190 - ../llvm/include/llvm/Support/FormatVariadicDetails.h
...

This requires duplicating the file_t typedef, which is unfortunate. I
sunk the choice of mapping mode down into the cpp file using variable
template specializations instead of class members in headers.

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Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly m

Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.

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[SampleFDO] Add profile remapping support for profile on-demand loading used
by ExtBinary format profile

Profile on-demand loading was added for ExtBinary format profile in rL374233,
but currently p

[SampleFDO] Add profile remapping support for profile on-demand loading used
by ExtBinary format profile

Profile on-demand loading was added for ExtBinary format profile in rL374233,
but currently profile on-demand loading doesn't work well with profile
remapping. The patch adds the support.

Suppose a function in the current module has outline instance in the profile.
The function name in the module is different from the name of the outline
instance, but remapper knows the two names are equal. When loading profile
on-demand, the outline instance has to be loaded with remapper's help.

At the same time SampleProfileReaderItaniumRemapper is changed from a proxy
of SampleProfileReader to a helper member in SampleProfileReader.

Differential Revision: https://reviews.llvm.org/D68901

llvm-svn: 375295

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[SampleFDO] Add indexing for function profiles so they can be loaded on demand
in ExtBinary format

Currently for Text, Binary and ExtBinary format profiles, when we compile a
module with samplefdo,

[SampleFDO] Add indexing for function profiles so they can be loaded on demand
in ExtBinary format

Currently for Text, Binary and ExtBinary format profiles, when we compile a
module with samplefdo, even if there is no function showing up in the profile,
we have to load all the function profiles from the profile input. That is a
waste of compile time.

CompactBinary format profile has already had the support of loading function
profiles on demand. In this patch, we add the support to load profile on
demand for ExtBinary format. It will work no matter the sections in ExtBinary
format profile are compressed or not. Experiment shows it reduces the time to
compile a server benchmark by 30%.

When profile remapping and loading function profiles on demand are both used,
extra work needs to be done so that the loading on demand process will take
the name remapping into consideration. It will be addressed in a follow-up
patch.

Differential Revision: https://reviews.llvm.org/D68601

llvm-svn: 374233

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[SampleFDO] Add profile symbol list section to discriminate function being
cold versus function being newly added.

This is the second half of https://reviews.llvm.org/D66374.

Profile symbol list is

[SampleFDO] Add profile symbol list section to discriminate function being
cold versus function being newly added.

This is the second half of https://reviews.llvm.org/D66374.

Profile symbol list is the collection of function symbols showing up in
the binary which generates the current profile. It is used to discriminate
function being cold versus function being newly added. Profile symbol list
is only added for profile with ExtBinary format.

During profile use compilation, when profile-sample-accurate is enabled,
a function without profile will be regarded as cold only when it is
contained in that list.

Differential Revision: https://reviews.llvm.org/D66766

llvm-svn: 370563

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[ADT] Make StringRef(const char*) constexpr

This should let us get rid of StringLiteral in the long term and avoid
chasing accidental StringRef globals once and for all.

This requires C++14, I godb

[ADT] Make StringRef(const char*) constexpr

This should let us get rid of StringLiteral in the long term and avoid
chasing accidental StringRef globals once and for all.

This requires C++14, I godbolted it on every compiler I know we support
so I hope there won't be much fallout.

llvm-svn: 369961

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[SampleFDO] Add ExtBinary format to support extension of binary profile.

This is a patch split from https://reviews.llvm.org/D66374. It tries to add
a new format of profile called ExtBinary. The for

[SampleFDO] Add ExtBinary format to support extension of binary profile.

This is a patch split from https://reviews.llvm.org/D66374. It tries to add
a new format of profile called ExtBinary. The format adds a section header
table to the profile and organize the profile in sections, so the future
extension like adding a new section or extending an existing section will be
easier while keeping backward compatiblity feasible.

Differential Revision: https://reviews.llvm.org/D66513

llvm-svn: 369798

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Rename F_{None,Text,Append} to OF_{None,Text,Append}. NFC

F_{None,Text,Append} are kept for compatibility since r334221.

llvm-svn: 367800

[SampleFDO] add suffix elision control for fcn names

Summary:
Add hooks for determining the policy used to decide whether/how
to chop off symbol 'suffixes' when locating a given function
in a sample

[SampleFDO] add suffix elision control for fcn names

Summary:
Add hooks for determining the policy used to decide whether/how
to chop off symbol 'suffixes' when locating a given function
in a sample profile.

Prior to this change, any function symbols of the form "X.Y" were
elided/truncated into just "X" when looking up things in a sample
profile data file.

With this change, the policy on suffixes can be changed by adding a
new attribute "sample-profile-suffix-elision-policy" to the function:
this attribute can have the value "all" (the default), "selected", or
"none". A value of "all" preserves the previous behavior (chop off
everything after the first "." character, then treat that as the
symbol name). A value of "selected" chops off only the rightmost
".llvm.XXXX" suffix (where "XXX" is any string not containing a "."
char). A value of "none" indicates that names should be left as is.

Subscribers: jdoerfert, wmi, mtrofin, danielcdh, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58832

llvm-svn: 356146

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[PGO] Context sensitive PGO (part 2)

Part 2 of CSPGO changes (mostly related to ProfileSummary).
Note that I use a default parameter in setProfileSummary() and getSummary().
This is to break the dep

[PGO] Context sensitive PGO (part 2)

Part 2 of CSPGO changes (mostly related to ProfileSummary).
Note that I use a default parameter in setProfileSummary() and getSummary().
This is to break the dependency in clang. I will make the parameter explicit
after changing clang in a separated patch.

Differential Revision: https://reviews.llvm.org/D54175

llvm-svn: 355131

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Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

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