[PGO] context sensitive PGO

[xur]

Summary

Current PGO profile counts are not context sensitive. The branch probabilities for the inlined functions are kept the same for all call-sites, and they might be very different from the actual branch probabilities. These suboptimal profile can greatly affect some downstream optimizations, in particular for machine basic block placement optimization.

In this patch, we propose to have a post-inline PGO instrumentation/use pass, which we called Context Sensitive PGO (CSPGO). For the users who want the best possible performance, they can perform a second round of PGO instrument/use on the top of the regular PGO. They will have two sets of profile counts. The first pass profile will be manly for inline, indirect-call promotion, and CGSCC simplification pass optimizations. The second pass profile is for post-inline optimizations and code-gen optimizations.

The typical usage models are:
// Regular PGO instrumentation and generate pass1 profile.

> clang -O2 -fprofile-generate source.c -o gen
> ./gen
> llvm-profdata merge default.*profraw -o pass1.profdata

// CSPGO instrumentation.

> clang -O2 -fprofile-use=pass1.profdata -fcs-profile-generate -o gen2
> ./gen2

// Merge two sets of profiles

> llvm-profdata merge default.*profraw pass1.profdata -o profile.profdata

// Use the combined profile. Pass manager will invoke two PGO use passes.

> clang -O2 -fprofile-use=profile.profdata -o use

The major changes are the following:

• bump index profile version to indicate if there are context-sensitive counts.
• change the FuncHash and reserve bits for context-sensitive counts.
• change the ProfileSummary interface as we might have two sets of profile summaries.
• change pass-manager (legacy and new)
• change llvm-profdata to handle two kind of profiles.
• change instrprofiling lowing for more aggressive register promotion for CSPGO.

Note that other than the FuncHash change, there is no effect on existing PGO pass.

This patches is functional tested using SPEC2006, with the various combinations of the following:

• legacy-pass manager
• new pass manager
• thin-lto (through gold plugin)
• thin-lto (though driver command line)
• lto (through plugin)
• non-lto

We performance-tested this patch with a few large Google benchmarks and saw good performance improvements.

I did not include any tests in this patch. I will add tests once the interfaces are decided in the code review.

[davidxl]

include/llvm/ProfileData/InstrProf.h

778

nit: FlaginHash --> FlagInHash

781

FlaginHash -> FlagInHash.

903

There is probably no need to bump the version number if there is a new variant bit set in the profile data. The format of existing variant do not change.

include/llvm/ProfileData/InstrProfReader.h

147

Why? It would be nice to add support in text reader as well.

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

674

This won't work well -- the non-CS FunctionHash may collide with CS hash. How do you differentiate?

Also doing this for nonCS profiling also breaks the backward compatibility -- old profile with high bits set in hash won't be found anymore. It may also create more hash conflicts.

[xur]

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

674

That is the reason I bump the version number. I use the version number to tell if this is old Hash format or new Hash format.

[davidxl]

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

674

Say there exists an old version profile with the 60-63 bits set for some functions. When this profile is used, the new compiler won't be able to find those functions.

Also where is the code that checks the version number?

[davidxl]

Test cases are missing in the patch.

[vsk]

Hi Rong, at a high-level, I like what this patch is doing. I'll try to leave in-depth comments by next week -- please ping the review otherwise.

These suboptimal profile can greatly affect some downstream optimizations, in particular for machine basic block placement optimization.

If it's possible to get these numbers, it'd be interesting to know how the improvements from this patch compare to link-time or post-link block ordering tools (Bolt).

[xur]

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

674

or this we will use one VARIANT bit in header to distinguish. AnnotateAllFunction will check if the VARIANT flag is set when reading CS profiles.
For old index profile, this won't be a problem as this bit will not be set.

This could be a problem for old raw profile. As of now, I did not change instrumentation run-time. So I could only use FuncHash to tell if this regular count or CS count. Setting of VARIANT bit in index profile relies on the new FuncHash scheme.

I can add change to profile runtime and set the VARIANT for raw profile. Then setting the VARIANT bit for index profile will not rely on check of FuncHash. This will fully backward compatible.

The new FuncHash scheme will be guarded by a check of VARIANT bit. Maybe we don't need bump the profile version.

Right now, It's only in IndexedInstrProfReader::readSummary(). I agree that we probably need to place more checks on this.

[xur]

In D54175#1291940, @vsk wrote:

Hi Rong, at a high-level, I like what this patch is doing. I'll try to leave in-depth comments by next week -- please ping the review otherwise.

Sounds good. Looking forward to your reviews.

These suboptimal profile can greatly affect some downstream optimizations, in particular for machine basic block placement optimization.

If it's possible to get these numbers, it'd be interesting to know how the improvements from this patch compare to link-time or post-link block ordering tools (Bolt).

We mainly use a key google benchmark for performance evaluation. Note that this benchmark has been highly tuned. A performance gain of 0.5% is considered significant.

Our experiments shows 1.5% to 2% from CSPGO. The improvement is mainly from machine basicblock placement. CSPGO also sets the accurate function entry count (for the cases that inline are cross module). That will make the hot-text section more dense. This can be seen from instruction heat map. But the performance improvement was small.

BOLT can have similar performance boosts from basic block reordering if it's applied to regular PGO binary (i.e. ~2%)
BOLT can improve the CSPGO binary by 0.5% and that is from function splitting, which is not currently enabled in llvm.

[davidxl]

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

674

I think it is better to emit variant bit in raw profile data. Relying on func hashing content sounds fragile.

The masking and adding bit in function hash is only needed for CS instrumentation and annotation. With this, the old profile (non CS) will still be valid. There is a slight downside that nonCS and CS profile can collide -- but this is very unlikely given all the inlining/cfg transformations that had happened.

[vsk]

include/llvm/Analysis/ProfileSummaryInfo.h

47

It doesn't seem necessary to add a flag to computeSummary or to add recomputeSummary to PSI's API.

Why not call ProfileSummaryInfo::invalidate when attaching CSPGO data to a Module? invalidate() could be modified to recompute the summary. That keeps the APIs a bit simpler.

include/llvm/IR/Module.h

869

I think {set, get}ProfileSummary would be safer & easier to understand if clients had to pass in a non-optional enum specifying which profile data kind they need (maybe use ProfileSummary::Kind for this?). That should make it impossible to mix-and-match CS + the wrong format.

include/llvm/IR/ProfileSummary.h

48–49

Does this really need to be in the header? Could we just take the opportunity to delete this declaration, and make the definition static?

include/llvm/Passes/PassBuilder.h

33–34

I think this could use a little more explanation (why would CSProfileGen not need ProfileUse?).

623–624

I think it'd be best to consolidate flags here, and replace {bool RunProfileGen, bool IsCS} with {enum InstrumentionKind} (or similar, there must be an enum for this already).

include/llvm/ProfileData/InstrProfReader.h

473–481

I'm not sure that the right behavior here should be to default to the non-context sensitive data. Why not either make the bool argument non-optional, or, take the max of the two?

500–508

I don't think the bool argument here should have a default value. Clients should explicitly pick which kind of summary they need.

include/llvm/ProfileData/InstrProfWriter.h

86

Using xor in this context is a bit unconventional. Could you rewrite this using ands/ors to make it easier to understand?

lib/ProfileData/InstrProfReader.cpp

770

No need to assert on the version, it's checked before readSummary is called.

770

Please write out the type of Summary here for clarity.

[xur]

Thanks vsk and david for the reviews. I will update the patch to integrate the comments.

include/llvm/Analysis/ProfileSummaryInfo.h

47

I agree that change invlidate() would be more clean (and better). My concern was that would change current behavior.
invalidate() be called by passmanager. Currently it does nothing, If I change that, profilesummary could be recomputed many time as most passes will invalidate all the analysis.

include/llvm/IR/Module.h

869

I will change to use an enum parameter (and no default).

include/llvm/IR/ProfileSummary.h

48–49

I think this is a good idea. the strings are only used in ProfileSummary.cpp. I will change.

include/llvm/Passes/PassBuilder.h

33–34

Sorry. This will be deleted.
I used this to work around an issue with out internal tool.

Thanks for catching this.

623–624

yes. I agree.

include/llvm/ProfileData/InstrProf.h

903

OK. no version change.

include/llvm/ProfileData/InstrProfReader.h

147

Text format is supported (mostly). I say mostly because there is not text string for CS format. But the flat is encoded in header (and in checksum).

473–481

I can change the take bool argument.

Taking max is not a good idea as the client need to know what kind of summary it uses. Mixing these two will cause wrong hot/cold attributes.

include/llvm/ProfileData/InstrProfWriter.h

86

OK. I will change to use and/or

lib/ProfileData/InstrProfReader.cpp

770

Do you mean comments?

[vsk]

include/llvm/Analysis/ProfileSummaryInfo.h

47

Would it be feasible to update any passes which inadvertently invalidate PSI to preserve it instead?

include/llvm/ProfileData/InstrProfReader.h

473–481

Sounds good.

lib/ProfileData/InstrProfReader.cpp

770

I meant 'ProfileSummary &Summary', instead of 'auto &Summary'. I think the coding guidelines suggest writing out the type explicitly when it may not be obvious from the immediate context. This is subjective though, I don't have a strong opinion about this.

[xur]

include/llvm/Analysis/ProfileSummaryInfo.h

47

I found that we don't need to invalidate summary.
Normal PGO-use pass is before per-function optimization passes
and CS pass of PGO-use is in per-module optimization passes.
They do not share the analyse pass result -- All the results in
per-function optimization pass are discarded and recomputed
again in per-module optimization pass.

I will revert this change.

include/llvm/Passes/PassBuilder.h

623–624

hmm. IsCS is also used by ProfileUse. Even I combine like this, I still need two flags.

include/llvm/ProfileData/InstrProfReader.h

147

Now. "csir" is supported keyword in proftext format.

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

674

Now the raw profile also emit variant.

But I still relying on funchash to tell if the profile for this function is CS or not.

I agree the chance of collision is low. I think what matter more is the summary computation. Functions with lots of select instruction will counts as CS profile and used in CS profile summary. This definitively happens but I'm not sure if matters for performance.

I lean to change the hash unconditionally. For old profiles, we will report a hash-mismatch and the users need to recollect the profile. I think this could happen for other compiler change (like changes before pgo instrumentation).

[xur]

This new version integrated the review comments from David and Vsk. Noticeable changes are:
(1) Combined the following 3 field in PGOOptions struct

bool RunProfileGen;
bool RunCSProfileGen;
bool RunCSProfileUse;

into an enum. There three are mutually exclusive.

(2) Not use default arguments for a set of functions.

(3) Don't bump up index profile version

(4) CS variant flag is set in raw profile and use that to tell if the profile has CS counters.

(5) Better handle in profile text format.

(7) Revert ProfileSummary recomputation as it is not needed.

(8) Fix a bug in the change to instrprofiling promotion.

I will also update
https://reviews.llvm.org/D54177
and
https://reviews.llvm.org/D54176

[xur]

Fix an issue in LegacyPassManager where CSPGO is not separated from -fprofile-use cleanly.

[tejohnson]

lib/LTO/LTOBackend.cpp

151

Presumably need a corresponding change in runOldPMPasses?

You'll also want to have a way to test via llvm-lto2. E.g. llvm-lto2 has an option for passing a sample profile.

tools/gold/gold-plugin.cpp

905

Needs tests

Also, support should be added to lld too - is there a separate patch for that?

tools/llvm-profdata/llvm-profdata.cpp

230

leftover debug output

[xur]

lib/LTO/LTOBackend.cpp

151

You are right. I need to set the options for oldPM.

tools/gold/gold-plugin.cpp

905

I haven't done lld patch yet. There are too many moving parts at this stage.

tools/llvm-profdata/llvm-profdata.cpp

230

Removed.

[xur]

Integrated with Teresa's review comments.

I will add tests in a later patch.

[tejohnson]

In D54175#1317088, @xur wrote:

Integrated with Teresa's review comments.

I will add tests in a later patch.

I really think that tests for gold and for LTO should be added with this patch, since it is adding the functionality for those.

lib/LTO/LTOBackend.cpp

283

Is it deliberate that here in the old PM the RunCSIRInstr and CSIRProfile are handled regardless of whether SampleProfile is set, whereas in the new PM they are only handled when SampleProfile is not set? What should be the behavior if sample profile is specified along with CS profiling?

[xur]

As for the tests, I meant to add test cases to this patch later, not through a different patch.
I can add tests now.

lib/LTO/LTOBackend.cpp

283

It's not deliberate. I should have make the behavior consistent.
I think I would like to change new PM and make CSProfile independent of SampleProfile.
The reason is that -fprofile-use and -fprofile-sample-use are independent.
This usage does not make a lot of sense, and we should probably give some warnings. But that should be in command line handling, not here.

What do you think?

[tejohnson]

In D54175#1317243, @xur wrote:

As for the tests, I meant to add test cases to this patch later, not through a different patch.

Oh got it - that's totally fine. I misunderstood.

I can add tests now.

include/llvm/Passes/PassBuilder.h

33–34

Shouldn't this be (Action == NoAction || ...)? I.e. either we are doing no PGO action, or we better have one of the other fields set?

lib/LTO/LTOBackend.cpp

283

Yeah it would be good to make them consistent. Looking at the new PM though, I'm not sure how you can make them independent with the existing PGOOptions interface.

I noticed a similar inconsistency between new and old PM on the clang side patch, although it looks like it predates your changes (with the newPM the sample profile is only looked at if no IR profiling enabled, in the old PM it is looked at unconditionally).

[xur]

include/llvm/Passes/PassBuilder.h

33–34

There are 4 possible values for Action: NoAction, IRInstr, CSIRInstr, CSIRUse
If NoAction, we need to have SampleProfileFile nonempty or ProfileUseFile nonempty. They are for sample fdo and fdo-use.
If the value is of the other 3 values, we don't check SampleProfile and ProfileUseFile.

I think this is correct but I agree the check can be improved.

lib/LTO/LTOBackend.cpp

283

SampleProfileFile, ProfileGenFile and ProfileUseFile are of different fields in PGOOptions interface. I think technically they can be independently set /checked. But it's really confusing if SampleProifle and Profile{Gen|Use}File are both on.

[tejohnson]

include/llvm/Passes/PassBuilder.h

33–34

I see. I think it would be a lot clearer if the Action was extended then to cover all the possible pgo types, it's confusing to have NoAction be set when e.g. sample profile or IR profile use is enabled.

lib/LTO/LTOBackend.cpp

283

Agree. Probably add some checking into PGOOptions that only one is set (maybe in combination with the extension to Action that I suggested above)?

[xur]

Synced to newest change and fixed a few issues.

[xur]

Ping.

If the reviewers are OK with the high level structures and the interfaces, I will start to add test cases.
I have also done the lld patch. I will submit a separated patch for review.

[tejohnson]

include/llvm/Passes/PassBuilder.h

33–34

Please address this comment (it's really unintuitive to have NoAction mean sample profile or IR profile use).

lib/LTO/LTOBackend.cpp

283

ping on this suggestion.

lib/Passes/PassBuilder.cpp

780

Add comment about the LTOPreLink check.

lib/Transforms/IPO/PassManagerBuilder.cpp

572

Document constant parameter (here and elsewhere). E.g. /*IsCS=*/true.

[xur]

This new pass addresses the review comments from Teresa. Main changes are:
(1) used two enums in PGOOptions:

enum PGOAction { NoAction, IRInstr, IRUse, SampleUse };
enum CSPGOAction { NoCSAction, CSIRInstr, CSIRUse };

The first enum is for regular PGO. We will use one ProfileFile string to represent the profile (instrument path or profile path).
CSPGOAction can be set when PGOAction == NaAction, or PGOAction==IRUse.
for CSIRUse, the profile is the same as ProfileFile. For CSIRInstr, we need another string CSProfileGenFile to represent instrumentation file name.

NewPMDDriver already use a similar method for regular PGO.

(2) Changed the clang options handling to give error message when -fsample-profile-use is used with -fprofile-use or -fprofile-generate.

(3) added support in tools/opt/NewPMDriver.cpp. This will be used in tests.

[xur]

Fixed the issue with lld (where lld is not happy with the COMDAT variables created
after LTO/ThinLTO)

Add the support of clang bootstrap for CSPGO.

Update the patch.

Tested this patch with google internal benchmarks (mostly for distributed ThinLTO).

Tested this patch with clang bootstrap for CSPGO.
(1) plain CSPGO (new and legacy pass manager).
(2) Thinlto CSPGO with plugin-opt to lld (new-experimental and legacy pass manager).
(3) Fulllto CSPGO with plugin-opt to lld (new-experimental and legacy pass manager).
CSPGO improves 1%-4% (wall time of ninja clang) upon regular PGO in clang bootstrap.
Thinlto and Fulllto is ~4% (wall time of ninja clang) in the new-experimental pass manager.
Compiling of individual files can improve up to 20%.

I'm working to add tests to this patch

Clang patch:
https://reviews.llvm.org/D54176

Compiler-rt patch:
https://reviews.llvm.org/D54177

lld patch:
https://reviews.llvm.org/D56675

[tejohnson]

Bunch of mostly nit suggestions about names and commenting, and a few questions. I like the improved profile action expression.

CMakeLists.txt

575

nit: indentation seems off

cmake/modules/HandleLLVMOptions.cmake

816

s/Nedd/Need

Also, I don't understand how the comment about needing to pass it to the backend compiler after ld-plugin relates to the handling below.

826

This part seems unrelated - probably split into a different patch?

include/llvm/Passes/PassBuilder.h

34–62

document different values (in both enums)

44

This ordering doesn't seem to match the ordering of the checks in the assert below. In any case, rather than have the documentation just duplicate the code (it doesn't really add anything this way), it would be better to split up the following assert into multiple, with more of a plain english explanation of each one.

include/llvm/ProfileData/InstrProf.h

769

document

1017

this is just the addition of bit 60 being the CS flag, right? Maybe just say that?

include/llvm/ProfileData/InstrProfReader.h

438

Document new parameter here and elsewhere. I assume it is legal to have both a CS and a non-CS summary in this object? In that case, maybe the parameter name should be something like UseCS.

include/llvm/Transforms/Instrumentation/InstrProfiling.h

63

document variable

include/llvm/Transforms/Instrumentation/PGOInstrumentation.h

38

document const parameter

lib/Passes/PassBuilder.cpp

525

Why do we skip size optimizations with CS?

[tejohnson]

lib/Passes/PassBuilder.cpp

784

document const parameter (here and in below call)

1031–1032

document const parameter

1155

document const parameter (here and below call)

lib/ProfileData/InstrProf.cpp

1044

nit - in createProfileNameVar the linkage initially set to weak any, then reset to external if supports comdat. Here you do the opposite - suggest making the logic the same in both places for consistency

lib/ProfileData/InstrProfReader.cpp

814–818

document const parameter here and in below call

lib/Transforms/IPO/PassManagerBuilder.cpp

536

s/proifle/profile/

537

Can you add a better explanation about linker issue - i.e. the linker wants to see all variables before the LTO link since it needs to resolve symbols/comdats.

574

document const parameter (here and below)

lib/Transforms/Instrumentation/InstrProfiling.cpp

275

document rationale for this equation

999–1005

Comment needed

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

409

document

435

document

555

document

669

Probably needs a slight expansion on why that other info shouldn't affect function hash.

682

why reorder this?

1465

document const parameter. also add comment for why this is not needed when IsCS

1515

I don't see where the new parameter PSI is getting used.

1649

Here and below, needs comment about why PSI when IsCS. But see comment in annotateAllFunctions - I don't see it getting used there?

tools/llvm-profdata/llvm-profdata.cpp

715

How about replace these 4 lines with just:

if (FuncIsCS != ShowCS)

continue;

tools/opt/NewPMDriver.cpp

104

Can you do something similar to D56749 (moving and consolidating these opts between PMs)?

222

Is this still TODO? I see handling further below.

256

As an aside - theoretically someone might want to do CS profiling without regular PGO. Is it worth supporting that combination?

unittests/ProfileData/InstrProfTest.cpp

178

document const param

804

ditto

[xur]

cmake/modules/HandleLLVMOptions.cmake

816

Fixed the typo.

I think currently -profile-instr-use flag is only added to CMAKE_CXX_FLAGS and CMAKE_C_FLAGS. I need them to pass to linker and shared linker also. Since there is no flag for CSIR use build. I have to pass them unconditionally. For regular PGO, the flag is void operation.

I'll remove the line of CMAKE_CXX_FLAGS and CMAKE_C_FLAGS

826

Moved the change to
https://reviews.llvm.org/D57068

include/llvm/Passes/PassBuilder.h

44

Make sense. I will change this part.

lib/Passes/PassBuilder.cpp

525

This is for the early inline. We skip the early inline if for optimization for size.
For CS, we will not do early inline either.

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

669

This change actually will affect function hash -- if an old profile is passed here, an non-cs record could be recognized as CS profile. But that will most likely result in a CFG hash mismatch where the user will get a warning.

682

not intentionally. I will revert this change.

1515

Good catch! This is from my other changes that fixes BB profile count. They should be removed.

1649

Fixed. PSI is not used here.

tools/llvm-profdata/llvm-profdata.cpp

715

Yes!

tools/opt/NewPMDriver.cpp

222

Yes. we should remove this TODO.

256

Since both CSprofile and non-CS-profile are merged into one profile. I think it's earlier to assume regular PGO is enabled for CSPGO. If there is a need for support the other way, I will add later.

[xur]

Integrated Teresa's review comments.

Also fixed a bug that can cause mismatch in new pass manager -- some optimization passes are under guard of PGOOptions::IRUse. LTOBackend sets PGOAction to NOAction for CSIRInstr (because regular profile is not passed down for CSIRInstr). This leads to different IR for CSIRInstr and CSIRUse.

This patch sets the PGOAction to IRUSE for CSIRInstr.

[xur]

Fixed a pass ordering issue in legacy pass manager for ThinLTO: Need to place CS Instrumentation after EliminateAvailableExternallyPass. This can cause duplicate profile variables that leads to bad profile for online profile merge.

Also synced the trunk and fixed a merge issue.

[tejohnson]

Mostly minor comments inline. But still missing tests. Needs testing via new gold-plugin and opt options. Should also add options to llvm-lto2 to enable testing the LTOBackend path without needing gold or any other specific linker.

include/llvm/Passes/PassBuilder.h

55

Should we also have IRUse when CSAction is CSIRInstr?

include/llvm/ProfileData/InstrProfReader.h

438

The same change should be done elsewhere in this class (document and change to UseCS). There are a couple other interfaces with the same option.

include/llvm/ProfileData/InstrProfWriter.h

77

Document new parameter (there is currently nowhere in the file that indicates CS means context sensitive).

include/llvm/Transforms/Instrumentation.h

91

Document new parameter here and further down in createInstrProfilingLegacyPass (there is currently nowhere in the file that indicates CS means context sensitive).

lib/Passes/PassBuilder.cpp

525

Please add comment to that effect.

lib/Transforms/IPO/PassManagerBuilder.cpp

283

Similar suggestion to the one I had for new PM (add comment about now not when IsCS).

lib/Transforms/Instrumentation/InstrProfiling.cpp

999–1005

typo in instrumentation (missing n in the middle).

tools/opt/opt.cpp

290

The reason I suggested moving this here was to use the same set of options to set up CSPGO for the old PM. But it doesn't seem like it is being set up when invoked via opt. I'd expect something down in AddOptimizationPasses like where it sets up regular IR PGO PassManagerBuilder options.

[davidxl]

Please also add a profile dumping/reading round trip test with isCS flag (there are existing similar test for llvm-profdata)

text-format --> index-format-> text-format : diff text-format

include/llvm/ProfileData/InstrProfWriter.h

91

What is this (promotion)'s use case?

include/llvm/Transforms/Instrumentation/PGOInstrumentation.h

31

Add documentation for the new class. Also explain why it needs to be created in a pass.

lib/Analysis/ProfileSummaryInfo.cpp

89

This is confusing. It is better to just pass 'IsCS' flag to getProfileSummary method.

lib/ProfileData/InstrProf.cpp

1015

nit: createProfileFileNameVar.

Can this one be split out as a NFC change?

tools/llvm-profdata/llvm-profdata.cpp

909

New option needs to be documented in command line guide.

[xur]

Integrated the review comments from Teresa and David.
Added unit tests for
(1) llvm-profdata
(2) context-sensitive profile summary
(3) opt new options and passes
(4) gold plugin
(5) using lto2 to test csgen and csuse.

[davidxl]

include/llvm/ProfileData/InstrProfWriter.h

91

Can you explain the 'promotion' case here (as comments)?

lib/Analysis/ProfileSummaryInfo.cpp

89

how about this comment?

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

497

Remove this.

[xur]

Fixed the missing changes David mentioned.

include/llvm/Passes/PassBuilder.h

55

CSIRInstr can run without IRUSE. CSIRUse needs to IRUse (the only reason is they share the profile).

include/llvm/ProfileData/InstrProfWriter.h

91

when merging a non-cs profile with cs profile, the result is cs profile.

lib/ProfileData/InstrProf.cpp

1015

split the change to nfc r353230.

tools/opt/opt.cpp

290

OK. Got it.

[xur]

Forgot to include one more test:
A test/Other/cspgo-O2-pipeline.ll

[xur]

Removed the unrelated instructions (comments) from the tests.

[tejohnson]

LGTM, but wait for @davidxl to do final approval since I'm not sure his last comments addressed.

[davidxl]

lgtm

[ABataev]

llvm/trunk/include/llvm/Transforms/Instrumentation/PGOInstrumentation.h

41 ↗

(On Diff #188465)

Seems to me, it breaks the build with the shared libraries. Could you take a look at this?
lib/Passes/CMakeFiles/LLVMPasses.dir/PassBuilder.cpp.o: In function `llvm::PGOInstrumentationGenCreateVar::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&)':
/build/llvm/include/llvm/Transforms/Instrumentation/PGOInstrumentation.h:42: undefined reference to `llvm::createProfileFileNameVar(llvm::Module&, llvm::StringRef)'
/build/llvm/include/llvm/Transforms/Instrumentation/PGOInstrumentation.h:43: undefined reference to `llvm::createIRLevelProfileFlagVar(llvm::Module&, bool)'

[rupprecht]

llvm/trunk/include/llvm/Transforms/Instrumentation/PGOInstrumentation.h

41 ↗

(On Diff #188465)

Not OP, but I also hit this. rL355346 should fix it.

[ABataev]

llvm/trunk/include/llvm/Transforms/Instrumentation/PGOInstrumentation.h

41 ↗

(On Diff #188465)

Thanks for the fix!

[hctim]

Looks like this commit has broken the clang-hexagon-elf#23291: build. PTAL :)

FAIL: LLVM :: Transforms/PGOProfile/thinlto_cspgo_gen.ll (41188 of 44167)
******************** TEST 'LLVM :: Transforms/PGOProfile/thinlto_cspgo_gen.ll' FAILED ********************
Script:
--
: 'RUN: at line 1';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/opt -module-summary /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/llvm/test/Transforms/PGOProfile/thinlto_cspgo_gen.ll -o /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp1.bc
: 'RUN: at line 2';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/opt -module-summary /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/llvm/test/Transforms/PGOProfile/Inputs/thinlto_cspgo_bar_gen.ll -o /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp2.bc
: 'RUN: at line 3';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/llvm-lto2 run -lto-cspgo-profile-file=alloc -lto-cspgo-gen -save-temps -o /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp1.bc /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp2.bc    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp1.bc,foo,pl    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp1.bc,bar,l    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp1.bc,main,plx    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp1.bc,__llvm_profile_filename,plx    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp1.bc,__llvm_profile_raw_version,plx    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp2.bc,bar,pl    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp2.bc,odd,pl    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp2.bc,even,pl    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp2.bc,__llvm_profile_filename,x    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp2.bc,__llvm_profile_raw_version,x
: 'RUN: at line 14';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/llvm-dis /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_gen.ll.tmp.1.4.opt.bc -o - | /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/FileCheck /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/llvm/test/Transforms/PGOProfile/thinlto_cspgo_gen.ll --check-prefix=CSGEN
--
Exit Code: 1

Command Output (stderr):
--
llvm-lto2: LTO::run failed: No available targets are compatible with triple "x86_64-unknown-linux-gnu"

--

********************
PASS: LLVM :: Transforms/PartiallyInlineLibCalls/nobuiltin.ll (41189 of 44167)
PASS: LLVM :: Transforms/PartiallyInlineLibCalls/bad-prototype.ll (41190 of 44167)
PASS: LLVM :: Transforms/PGOProfile/memop_size_annotation.ll (41191 of 44167)
PASS: LLVM :: Transforms/PGOProfile/loop1.ll (41192 of 44167)
PASS: LLVM :: Transforms/PhaseOrdering/2010-03-22-empty-baseclass.ll (41193 of 44167)
PASS: LLVM :: Transforms/PGOProfile/loop2.ll (41194 of 44167)
FAIL: LLVM :: Transforms/PGOProfile/thinlto_cspgo_use.ll (41195 of 44167)
******************** TEST 'LLVM :: Transforms/PGOProfile/thinlto_cspgo_use.ll' FAILED ********************
Script:
--
: 'RUN: at line 1';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/opt -module-summary /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/llvm/test/Transforms/PGOProfile/thinlto_cspgo_use.ll -o /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp1.bc
: 'RUN: at line 2';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/opt -module-summary /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/llvm/test/Transforms/PGOProfile/Inputs/thinlto_cspgo_bar_use.ll -o /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp2.bc
: 'RUN: at line 3';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/llvm-profdata merge /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/llvm/test/Transforms/PGOProfile/Inputs/thinlto_cs.proftext -o /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp3.profdata
: 'RUN: at line 4';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/llvm-lto2 run -lto-cspgo-profile-file=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp3.profdata -save-temps -o /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp1.bc /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp2.bc    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp1.bc,foo,pl    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp1.bc,bar,l    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp1.bc,main,plx    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp2.bc,bar,pl    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp2.bc,odd,pl    -r=/var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp2.bc,even,pl
: 'RUN: at line 11';   /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/llvm-dis /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/test/Transforms/PGOProfile/Output/thinlto_cspgo_use.ll.tmp.1.4.opt.bc -o - | /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/stage1/bin/FileCheck /var/lib/buildbot/slaves/hexagon-build-03/clang-hexagon-elf/llvm/test/Transforms/PGOProfile/thinlto_cspgo_use.ll --check-prefix=CSUSE
--
Exit Code: 1

Command Output (stderr):
--
llvm-lto2: LTO::run failed: No available targets are compatible with triple "x86_64-unknown-linux-gnu"

--

********************

[pcc]

llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp

673 ↗

(On Diff #188465)

Hi Rong, I discovered a problem with this line of code. If the number of select instructions when the profile was collected differs by a multiple of 16 from the number when the profile is used, we get a hash collision which results in us hitting an assertion here:
http://llvm-cs.pcc.me.uk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp#1042

Granted, the same problem seems to have already existed for differences that are multiples of 256, but this seems to make the problem more likely to occur.

[xur]

llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp

673 ↗

(On Diff #188465)

I sent this patch for review.

https://reviews.llvm.org/D60154

CMakeLists.txt

if(NOT LLVM_PROFILE_MERGE_POOL_SIZE)
     set(LLVM_PROFILE_MERGE_POOL_SIZE "4")
   endif()
   if(NOT LLVM_PROFILE_FILE_PATTERN)
     if(NOT LLVM_PROFILE_DATA_DIR)
       file(TO_NATIVE_PATH "${LLVM_BINARY_DIR}/profiles" LLVM_PROFILE_DATA_DIR)
     endif()
     file(TO_NATIVE_PATH "${LLVM_PROFILE_DATA_DIR}/%${LLVM_PROFILE_MERGE_POOL_SIZE}m.profraw" LLVM_PROFILE_FILE_PATTERN)
   endif()
+  if(NOT LLVM_CSPROFILE_FILE_PATTERN)
+    if(NOT LLVM_CSPROFILE_DATA_DIR)
+      file(TO_NATIVE_PATH "${LLVM_BINARY_DIR}/csprofiles" LLVM_CSPROFILE_DATA_DIR)
+    endif()
+    file(TO_NATIVE_PATH "${LLVM_CSPROFILE_DATA_DIR}/%${LLVM_PROFILE_MERGE_POOL_SIZE}m.profraw" LLVM_CSPROFILE_FILE_PATTERN)
+  endif()
 endif()
 
 if (LLVM_BUILD_STATIC)
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static")
 endif()
 
 # Override the default target with an environment variable named by LLVM_TARGET_TRIPLE_ENV.
 set(LLVM_TARGET_TRIPLE_ENV CACHE STRING "The name of environment variable to override default target. Disabled by blank.")

cmake/modules/HandleLLVMOptions.cmake

 
 if (LLVM_BUILD_INSTRUMENTED)
   if (LLVM_ENABLE_IR_PGO OR uppercase_LLVM_BUILD_INSTRUMENTED STREQUAL "IR")
     append("-fprofile-generate='${LLVM_PROFILE_DATA_DIR}'"
       CMAKE_CXX_FLAGS
       CMAKE_C_FLAGS
       CMAKE_EXE_LINKER_FLAGS
       CMAKE_SHARED_LINKER_FLAGS)
+  elseif(uppercase_LLVM_BUILD_INSTRUMENTED STREQUAL "CSIR")
+    append("-fcs-profile-generate='${LLVM_CSPROFILE_DATA_DIR}'"
+      CMAKE_CXX_FLAGS
+      CMAKE_C_FLAGS
+      CMAKE_EXE_LINKER_FLAGS
+      CMAKE_SHARED_LINKER_FLAGS)
   else()
     append("-fprofile-instr-generate='${LLVM_PROFILE_FILE_PATTERN}'"
       CMAKE_CXX_FLAGS
       CMAKE_C_FLAGS
       CMAKE_EXE_LINKER_FLAGS
       CMAKE_SHARED_LINKER_FLAGS)
   endif()
 endif()
 
+# Need to pass -fprofile-instr-use to linker for context-sensitive PGO
+# compilation.
+if(LLVM_PROFDATA_FILE AND EXISTS ${LLVM_PROFDATA_FILE})
+    append("-fprofile-instr-use='${LLVM_PROFDATA_FILE}'"
+      CMAKE_EXE_LINKER_FLAGS
+      CMAKE_SHARED_LINKER_FLAGS)
+endif()
+
 option(LLVM_BUILD_INSTRUMENTED_COVERAGE "Build LLVM and tools with Code Coverage instrumentation" Off)
 mark_as_advanced(LLVM_BUILD_INSTRUMENTED_COVERAGE)
 append_if(LLVM_BUILD_INSTRUMENTED_COVERAGE "-fprofile-instr-generate='${LLVM_PROFILE_FILE_PATTERN}' -fcoverage-mapping"
   CMAKE_CXX_FLAGS
   CMAKE_C_FLAGS
   CMAKE_EXE_LINKER_FLAGS
   CMAKE_SHARED_LINKER_FLAGS)
 
 if (LLVM_BUILD_INSTRUMENTED AND LLVM_BUILD_INSTRUMENTED_COVERAGE)
   message(FATAL_ERROR "LLVM_BUILD_INSTRUMENTED and LLVM_BUILD_INSTRUMENTED_COVERAGE cannot both be specified")
 endif()

include/llvm/Analysis/ProfileSummaryInfo.h

 /// check whether a function is hot or cold.
 
 // FIXME: Provide convenience methods to determine hotness/coldness of other IR
 // units. This would require making this depend on BFI.
 class ProfileSummaryInfo {
 private:
   Module &M;
   std::unique_ptr<ProfileSummary> Summary;
   bool computeSummary();
   void computeThresholds();
   // Count thresholds to answer isHotCount and isColdCount queries.
   Optional<uint64_t> HotCountThreshold, ColdCountThreshold;
   // True if the working set size of the code is considered huge,
   // because the number of profile counts required to reach the hot
   // percentile is above a huge threshold.
   Optional<bool> HasHugeWorkingSetSize;
 
public:
   }
 
   /// Returns true if module \c M has instrumentation profile.
   bool hasInstrumentationProfile() {
     return hasProfileSummary() &&
            Summary->getKind() == ProfileSummary::PSK_Instr;
   }
 
+  /// Returns true if module \c M has context sensitive instrumentation profile.
+  bool hasCSInstrumentationProfile() {
+    return hasProfileSummary() &&
+           Summary->getKind() == ProfileSummary::PSK_CSInstr;
+  }
+
   /// Handle the invalidation of this information.
   ///
   /// When used as a result of \c ProfileSummaryAnalysis this method will be
   /// called when the module this was computed for changes. Since profile
   /// summary is immutable after it is annotated on the module, we return false
   /// here.
   bool invalidate(Module &, const PreservedAnalyses &,
                   ModuleAnalysisManager::Invalidator &) {

include/llvm/IR/Module.h

 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/Comdat.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalIFunc.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/Metadata.h"
+#include "llvm/IR/ProfileSummary.h"
 #include "llvm/IR/SymbolTableListTraits.h"
 #include "llvm/Support/CBindingWrapping.h"
 #include "llvm/Support/CodeGen.h"
 #include <cstddef>
 #include <cstdint>
 #include <iterator>
 #include <memory>
 #include <string>
/// @}
   /// Set the code model (tiny, small, kernel, medium or large)
   void setCodeModel(CodeModel::Model CL);
   /// @}
 
   /// @name Utility functions for querying and setting PGO summary
   /// @{
 
   /// Attach profile summary metadata to this module.
-  void setProfileSummary(Metadata *M);
+  void setProfileSummary(Metadata *M, ProfileSummary::Kind Kind);
 
   /// Returns profile summary metadata
-  Metadata *getProfileSummary();
+  Metadata *getProfileSummary(ProfileSummary::Kind Kind);
   /// @}
 
   /// Returns true if PLT should be avoided for RTLib calls.
   bool getRtLibUseGOT() const;
 
   /// Set that PLT should be avoid for RTLib calls.
   void setRtLibUseGOT();
 

include/llvm/IR/ProfileSummary.h

ProfileSummaryEntry(uint32_t TheCutoff, uint64_t TheMinCount,
                       uint64_t TheNumCounts)
       : Cutoff(TheCutoff), MinCount(TheMinCount), NumCounts(TheNumCounts) {}
 };
 
 using SummaryEntryVector = std::vector<ProfileSummaryEntry>;
 
 class ProfileSummary {
 public:
-  enum Kind { PSK_Instr, PSK_Sample };
+  enum Kind { PSK_Instr, PSK_CSInstr, PSK_Sample };
 
 private:
   const Kind PSK;
-  static const char *KindStr[2];
   SummaryEntryVector DetailedSummary;
   uint64_t TotalCount, MaxCount, MaxInternalCount, MaxFunctionCount;
   uint32_t NumCounts, NumFunctions;
   /// Return detailed summary as metadata.
   Metadata *getDetailedSummaryMD(LLVMContext &Context);
 
 public:
   static const int Scale = 1000000;
 

include/llvm/InitializePasses.h

 void initializeObjCARCOptPass(PassRegistry&);
 void initializeOptimizationRemarkEmitterWrapperPassPass(PassRegistry&);
 void initializeOptimizePHIsPass(PassRegistry&);
 void initializePAEvalPass(PassRegistry&);
 void initializePEIPass(PassRegistry&);
 void initializePGOIndirectCallPromotionLegacyPassPass(PassRegistry&);
 void initializePGOInstrumentationGenLegacyPassPass(PassRegistry&);
 void initializePGOInstrumentationUseLegacyPassPass(PassRegistry&);
+void initializePGOInstrumentationGenCreateVarLegacyPassPass(PassRegistry&);
 void initializePGOMemOPSizeOptLegacyPassPass(PassRegistry&);
 void initializePHIEliminationPass(PassRegistry&);
 void initializePartialInlinerLegacyPassPass(PassRegistry&);
 void initializePartiallyInlineLibCallsLegacyPassPass(PassRegistry&);
 void initializePatchableFunctionPass(PassRegistry&);
 void initializePeepholeOptimizerPass(PassRegistry&);
 void initializePhiValuesWrapperPassPass(PassRegistry&);
 void initializePhysicalRegisterUsageInfoPass(PassRegistry&);

include/llvm/LTO/Config.h

struct Config {
 
   /// Flag to indicate that the optimizer should not assume builtins are present
   /// on the target.
   bool Freestanding = false;
 
   /// Disable entirely the optimizer, including importing for ThinLTO
   bool CodeGenOnly = false;
 
+  /// Run PGO context sensitive IR instrumentation.
+  bool RunCSIRInstr = false;
+
   /// If this field is set, the set of passes run in the middle-end optimizer
   /// will be the one specified by the string. Only works with the new pass
   /// manager as the old one doesn't have this ability.
   std::string OptPipeline;
 
   // If this field is set, it has the same effect of specifying an AA pipeline
   // identified by the string. Only works with the new pass manager, in
   // conjunction OptPipeline.
   std::string AAPipeline;
 
   /// Setting this field will replace target triples in input files with this
   /// triple.
   std::string OverrideTriple;
 
   /// Setting this field will replace unspecified target triples in input files
   /// with this triple.
   std::string DefaultTriple;
 
+  /// Context Sensitive PGO profile path.
+  std::string CSIRProfile;
+
   /// Sample PGO profile path.
   std::string SampleProfile;
 
   /// Name remapping file for profile data.
   std::string ProfileRemapping;
 
   /// The directory to store .dwo files.
   std::string DwoDir;

include/llvm/LinkAllPasses.h

ForcePassLinking() {
       (void) llvm::createDependenceAnalysisWrapperPass();
       (void) llvm::createDomOnlyPrinterPass();
       (void) llvm::createDomPrinterPass();
       (void) llvm::createDomOnlyViewerPass();
       (void) llvm::createDomViewerPass();
       (void) llvm::createGCOVProfilerPass();
       (void) llvm::createPGOInstrumentationGenLegacyPass();
       (void) llvm::createPGOInstrumentationUseLegacyPass();
+      (void) llvm::createPGOInstrumentationGenCreateVarLegacyPass();
       (void) llvm::createPGOIndirectCallPromotionLegacyPass();
       (void) llvm::createPGOMemOPSizeOptLegacyPass();
       (void) llvm::createInstrProfilingLegacyPass();
       (void) llvm::createFunctionImportPass();
       (void) llvm::createFunctionInliningPass();
       (void) llvm::createAlwaysInlinerLegacyPass();
       (void) llvm::createGlobalDCEPass();
       (void) llvm::createGlobalOptimizerPass();

include/llvm/Passes/PassBuilder.h

 
 namespace llvm {
 class StringRef;
 class AAManager;
 class TargetMachine;
 class ModuleSummaryIndex;
 
 /// A struct capturing PGO tunables.
 struct PGOOptions {
-  PGOOptions(std::string ProfileGenFile = "", std::string ProfileUseFile = "",
-             std::string SampleProfileFile = "",
-             std::string ProfileRemappingFile = "",
-             bool RunProfileGen = false, bool SamplePGOSupport = false)
-      : ProfileGenFile(ProfileGenFile), ProfileUseFile(ProfileUseFile),
-        SampleProfileFile(SampleProfileFile),
-        ProfileRemappingFile(ProfileRemappingFile),
-        RunProfileGen(RunProfileGen),
-        SamplePGOSupport(SamplePGOSupport || !SampleProfileFile.empty()) {
-    assert((RunProfileGen ||
-            !SampleProfileFile.empty() ||
-            !ProfileUseFile.empty() ||
-            SamplePGOSupport) && "Illegal PGOOptions.");
-  }
-  std::string ProfileGenFile;
-  std::string ProfileUseFile;
-  std::string SampleProfileFile;
+  enum PGOAction { NoAction, IRInstr, IRUse, SampleUse };
+  enum CSPGOAction { NoCSAction, CSIRInstr, CSIRUse };
+  PGOOptions(std::string ProfileFile = "", std::string CSProfileGenFile = "",
+             std::string ProfileRemappingFile = "", PGOAction Action = NoAction,
+             CSPGOAction CSAction = NoCSAction, bool SamplePGOSupport = false)
+      : ProfileFile(ProfileFile), CSProfileGenFile(CSProfileGenFile),
+        ProfileRemappingFile(ProfileRemappingFile), Action(Action),
+        CSAction(CSAction),
+        SamplePGOSupport(SamplePGOSupport || Action == SampleUse) {
+    // Note, we do allow ProfileFile.empty() for Action=IRUse LTO can
+    // callback with IRUse action without ProfileFile.
+
+    // If there is a CSAction, PGOAction cannot be IRInstr or SampleUse.
+    assert(this->CSAction == NoCSAction ||
+           (this->Action != IRInstr && this->Action != SampleUse));
+
+    // For CSIRInstr, CSProfileGenFile also needs to be nonempty.
+    assert(this->CSAction != CSIRInstr || !this->CSProfileGenFile.empty());
+
+    // If CSAction is CSIRUse, PGOAction needs to be IRUse as they share
+    // a profile.
+    assert(this->CSAction != CSIRUse || this->Action == IRUse);
+
+    // If neither CSAction nor CSAction, SamplePGOSupport needs to be true.
+    assert(this->Action != NoAction || this->CSAction != NoCSAction ||
+           this->SamplePGOSupport);
+  }
+  std::string ProfileFile;
+  std::string CSProfileGenFile;
   std::string ProfileRemappingFile;
-  bool RunProfileGen;
+  PGOAction Action;
+  CSPGOAction CSAction;
   bool SamplePGOSupport;
 };
 
 /// This class provides access to building LLVM's passes.
 ///
 /// It's members provide the baseline state available to passes during their
 /// construction. The \c PassRegistry.def file specifies how to construct all
 /// of the built-in passes, and those may reference these members during
public:
   /// without potentially seriously regressing either runtime performance of
   /// the code or serious code size growth.
   ///
   /// Note that \p Level cannot be `O0` here. The pipelines produced are
   /// only intended for use when attempting to optimize code. If frontends
   /// require some transformations for semantic reasons, they should explicitly
   /// build them.
   ModulePassManager buildModuleOptimizationPipeline(OptimizationLevel Level,
-                                                    bool DebugLogging = false);
+                                                    bool DebugLogging = false,
+                                                    bool LTOPreLink = false);
 
   /// Build a per-module default optimization pipeline.
   ///
   /// This provides a good default optimization pipeline for per-module
   /// optimization and code generation without any link-time optimization. It
   /// typically correspond to frontend "-O[123]" options for optimization
   /// levels \c O1, \c O2 and \c O3 resp.
   ///
   /// Note that \p Level cannot be `O0` here. The pipelines produced are
   /// only intended for use when attempting to optimize code. If frontends
   /// require some transformations for semantic reasons, they should explicitly
   /// build them.
   ModulePassManager buildPerModuleDefaultPipeline(OptimizationLevel Level,
-                                                  bool DebugLogging = false);
+                                                  bool DebugLogging = false,
+                                                  bool LTOPreLink = false);
 
   /// Build a pre-link, ThinLTO-targeting default optimization pipeline to
   /// a pass manager.
   ///
   /// This adds the pre-link optimizations tuned to prepare a module for
   /// a ThinLTO run. It works to minimize the IR which needs to be analyzed
   /// without making irreversible decisions which could be made better during
   /// the LTO run.
private:
   Error parseCGSCCPassPipeline(CGSCCPassManager &CGPM,
                                ArrayRef<PipelineElement> Pipeline,
                                bool VerifyEachPass, bool DebugLogging);
   Error parseModulePassPipeline(ModulePassManager &MPM,
                                 ArrayRef<PipelineElement> Pipeline,
                                 bool VerifyEachPass, bool DebugLogging);
 
   void addPGOInstrPasses(ModulePassManager &MPM, bool DebugLogging,
-                         OptimizationLevel Level, bool RunProfileGen,
-                         std::string ProfileGenFile,
-                         std::string ProfileUseFile,
+                         OptimizationLevel Level, bool RunProfileGen, bool IsCS,
+                         std::string ProfileFile,
                          std::string ProfileRemappingFile);
 
   void invokePeepholeEPCallbacks(FunctionPassManager &, OptimizationLevel);
 
   // Extension Point callbacks
   SmallVector<std::function<void(FunctionPassManager &, OptimizationLevel)>, 2>
       PeepholeEPCallbacks;
   SmallVector<std::function<void(LoopPassManager &, OptimizationLevel)>, 2>

include/llvm/ProfileData/InstrProf.h

private:
   // Scale up value profile data count.
   void scaleValueProfData(uint32_t ValueKind, uint64_t Weight,
                           function_ref<void(instrprof_error)> Warn);
 };
 
 struct NamedInstrProfRecord : InstrProfRecord {
   StringRef Name;
   uint64_t Hash;
 
+  // We reserve this bit as the flag for context sensitive profile record.
+  static const int CS_FLAG_IN_FUNC_HASH = 60;
+
   NamedInstrProfRecord() = default;
   NamedInstrProfRecord(StringRef Name, uint64_t Hash,
                        std::vector<uint64_t> Counts)
       : InstrProfRecord(std::move(Counts)), Name(Name), Hash(Hash) {}
+
+  static bool hasCSFlagInHash(uint64_t FuncHash) {
+    return ((FuncHash >> CS_FLAG_IN_FUNC_HASH) & 1);
+  }
+  static void setCSFlagInHash(uint64_t &FuncHash) {
+    FuncHash |= ((uint64_t)1 << CS_FLAG_IN_FUNC_HASH);
+  }
 };
 
 uint32_t InstrProfRecord::getNumValueKinds() const {
   uint32_t NumValueKinds = 0;
   for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
     NumValueKinds += !(getValueSitesForKind(Kind).empty());
   return NumValueKinds;
 }
enum ProfVersion {
   Version3 = 3,
   // In this version, profile summary data \c IndexedInstrProf::Summary is
   // stored after the profile header.
   Version4 = 4,
   // In this version, the frontend PGO stable hash algorithm defaults to V2.
   Version5 = 5,
   // The current version is 5.
   CurrentVersion = INSTR_PROF_INDEX_VERSION
 };
 const uint64_t Version = ProfVersion::CurrentVersion;
 
 const HashT HashType = HashT::MD5;
 
 inline uint64_t ComputeHash(StringRef K) { return ComputeHash(HashType, K); }
 
 // This structure defines the file header of the LLVM profile
 // data file in indexed-format.

 
 // Version 1: First version
 // Version 2: Added value profile data section. Per-function control data
 // struct has more fields to describe value profile information.
 // Version 3: Compressed name section support. Function PGO name reference
 // from control data struct is changed from raw pointer to Name's MD5 value.
 // Version 4: ValueDataBegin and ValueDataSizes fields are removed from the
 // raw header.
+// Version 5: Bit 60 of FuncHash is reserved for the flag for the context
+// sensitive records.
 const uint64_t Version = INSTR_PROF_RAW_VERSION;
 
 template <class IntPtrT> inline uint64_t getMagic();
 template <> inline uint64_t getMagic<uint64_t>() {
   return INSTR_PROF_RAW_MAGIC_64;
 }
 
 template <> inline uint64_t getMagic<uint32_t>() {

 };
 
 } // end namespace RawInstrProf
 
 // Parse MemOP Size range option.
 void getMemOPSizeRangeFromOption(StringRef Str, int64_t &RangeStart,
                                  int64_t &RangeLast);
 
+// Create a COMDAT variable INSTR_PROF_RAW_VERSION_VAR to make the runtime
+// aware this is an ir_level profile so it can set the version flag.
+void createIRLevelProfileFlagVar(Module &M, bool IsCS);
+
+// Create variable for profile name.
+void createProfileNameVar(Module &M, StringRef InstrProfileOutput);
+
 } // end namespace llvm
 
 #endif // LLVM_PROFILEDATA_INSTRPROF_H

include/llvm/ProfileData/InstrProfData.inc

 #define INSTR_PROF_INDEX_VERSION 5
 /* Coverage mapping format vresion (start from 0). */
 #define INSTR_PROF_COVMAP_VERSION 2
 
 /* Profile version is always of type uint64_t. Reserve the upper 8 bits in the
  * version for other variants of profile. We set the lowest bit of the upper 8
  * bits (i.e. bit 56) to 1 to indicate if this is an IR-level instrumentaiton
  * generated profile, and 0 if this is a Clang FE generated profile.
+ * 1 in bit 57 indicates there are context-sensitive records in the profile.
  */
 #define VARIANT_MASKS_ALL 0xff00000000000000ULL
 #define GET_VERSION(V) ((V) & ~VARIANT_MASKS_ALL)
 #define VARIANT_MASK_IR_PROF (0x1ULL << 56)
+#define VARIANT_MASK_CSIR_PROF (0x1ULL << 57)
 #define INSTR_PROF_RAW_VERSION_VAR __llvm_profile_raw_version
 #define INSTR_PROF_PROFILE_RUNTIME_VAR __llvm_profile_runtime
 
 /* The variable that holds the name of the profile data
  * specified via command line. */
 #define INSTR_PROF_PROFILE_NAME_VAR __llvm_profile_filename
 
 /* section name strings common to all targets other

include/llvm/ProfileData/InstrProfReader.h

public:
   virtual Error readNextRecord(NamedInstrProfRecord &Record) = 0;
 
   /// Iterator over profile data.
   InstrProfIterator begin() { return InstrProfIterator(this); }
   InstrProfIterator end() { return InstrProfIterator(); }
 
   virtual bool isIRLevelProfile() const = 0;
 
+  virtual bool hasCSIRLevelProfile() const = 0;
+
   /// Return the PGO symtab. There are three different readers:
   /// Raw, Text, and Indexed profile readers. The first two types
   /// of readers are used only by llvm-profdata tool, while the indexed
   /// profile reader is also used by llvm-cov tool and the compiler (
   /// backend or frontend). Since creating PGO symtab can create
   /// significant runtime and memory overhead (as it touches data
   /// for the whole program), InstrProfSymtab for the indexed profile
   /// reader should be created on demand and it is recommended to be

 /// counters, and then each counter value, in that order.
 class TextInstrProfReader : public InstrProfReader {
 private:
   /// The profile data file contents.
   std::unique_ptr<MemoryBuffer> DataBuffer;
   /// Iterator over the profile data.
   line_iterator Line;
   bool IsIRLevelProfile = false;
+  bool HasCSIRLevelProfile = false;
 
   Error readValueProfileData(InstrProfRecord &Record);
 
 public:
   TextInstrProfReader(std::unique_ptr<MemoryBuffer> DataBuffer_)
       : DataBuffer(std::move(DataBuffer_)), Line(*DataBuffer, true, '#') {}
   TextInstrProfReader(const TextInstrProfReader &) = delete;
   TextInstrProfReader &operator=(const TextInstrProfReader &) = delete;
 
   /// Return true if the given buffer is in text instrprof format.
   static bool hasFormat(const MemoryBuffer &Buffer);
 
   bool isIRLevelProfile() const override { return IsIRLevelProfile; }
 
+  bool hasCSIRLevelProfile() const override { return HasCSIRLevelProfile; }
+
   /// Read the header.
   Error readHeader() override;
 
   /// Read a single record.
   Error readNextRecord(NamedInstrProfRecord &Record) override;
 
   InstrProfSymtab &getSymtab() override {
     assert(Symtab.get());
public:
   static bool hasFormat(const MemoryBuffer &DataBuffer);
   Error readHeader() override;
   Error readNextRecord(NamedInstrProfRecord &Record) override;
 
   bool isIRLevelProfile() const override {
     return (Version & VARIANT_MASK_IR_PROF) != 0;
   }
 
+  bool hasCSIRLevelProfile() const override {
+    return (Version & VARIANT_MASK_CSIR_PROF) != 0;
+  }
+
   InstrProfSymtab &getSymtab() override {
     assert(Symtab.get());
     return *Symtab.get();
   }
 
 private:
   Error createSymtab(InstrProfSymtab &Symtab);
   Error readNextHeader(const char *CurrentPos);
struct InstrProfReaderIndexBase {
   // Read all the profile records with the key equal to FuncName
   virtual Error getRecords(StringRef FuncName,
                                      ArrayRef<NamedInstrProfRecord> &Data) = 0;
   virtual void advanceToNextKey() = 0;
   virtual bool atEnd() const = 0;
   virtual void setValueProfDataEndianness(support::endianness Endianness) = 0;
   virtual uint64_t getVersion() const = 0;
   virtual bool isIRLevelProfile() const = 0;
+  virtual bool hasCSIRLevelProfile() const = 0;
   virtual Error populateSymtab(InstrProfSymtab &) = 0;
 };
 
 using OnDiskHashTableImplV3 =
     OnDiskIterableChainedHashTable<InstrProfLookupTrait>;
 
 template <typename HashTableImpl>
 class InstrProfReaderItaniumRemapper;
public:
   }
 
   uint64_t getVersion() const override { return GET_VERSION(FormatVersion); }
 
   bool isIRLevelProfile() const override {
     return (FormatVersion & VARIANT_MASK_IR_PROF) != 0;
   }
 
+  bool hasCSIRLevelProfile() const override {
+    return (FormatVersion & VARIANT_MASK_CSIR_PROF) != 0;
+  }
+
   Error populateSymtab(InstrProfSymtab &Symtab) override {
     return Symtab.create(HashTable->keys());
   }
 };
 
 /// Name matcher supporting fuzzy matching of symbol names to names in profiles.
 class InstrProfReaderRemapper {
 public:
private:
   /// The profile remapping file contents.
   std::unique_ptr<MemoryBuffer> RemappingBuffer;
   /// The index into the profile data.
   std::unique_ptr<InstrProfReaderIndexBase> Index;
   /// The profile remapping file contents.
   std::unique_ptr<InstrProfReaderRemapper> Remapper;
   /// Profile summary data.
   std::unique_ptr<ProfileSummary> Summary;
+  /// Context sensitive profile summary data.
+  std::unique_ptr<ProfileSummary> CS_Summary;
   // Index to the current record in the record array.
   unsigned RecordIndex;
 
   // Read the profile summary. Return a pointer pointing to one byte past the
   // end of the summary data if it exists or the input \c Cur.
+  // \c UseCS indicates whether to use context-sensitive profile summary.
   const unsigned char *readSummary(IndexedInstrProf::ProfVersion Version,
-                                   const unsigned char *Cur);
+                                   const unsigned char *Cur, bool UseCS);
 
 public:
   IndexedInstrProfReader(
       std::unique_ptr<MemoryBuffer> DataBuffer,
       std::unique_ptr<MemoryBuffer> RemappingBuffer = nullptr)
       : DataBuffer(std::move(DataBuffer)),
         RemappingBuffer(std::move(RemappingBuffer)), RecordIndex(0) {}
   IndexedInstrProfReader(const IndexedInstrProfReader &) = delete;
   IndexedInstrProfReader &operator=(const IndexedInstrProfReader &) = delete;
 
   /// Return the profile version.
   uint64_t getVersion() const { return Index->getVersion(); }
   bool isIRLevelProfile() const override { return Index->isIRLevelProfile(); }
+  bool hasCSIRLevelProfile() const override {
+    return Index->hasCSIRLevelProfile();
+  }
 
   /// Return true if the given buffer is in an indexed instrprof format.
   static bool hasFormat(const MemoryBuffer &DataBuffer);
 
   /// Read the file header.
   Error readHeader() override;
   /// Read a single record.
   Error readNextRecord(NamedInstrProfRecord &Record) override;
 
   /// Return the NamedInstrProfRecord associated with FuncName and FuncHash
   Expected<InstrProfRecord> getInstrProfRecord(StringRef FuncName,
                                                uint64_t FuncHash);
 
   /// Fill Counts with the profile data for the given function name.
   Error getFunctionCounts(StringRef FuncName, uint64_t FuncHash,
                           std::vector<uint64_t> &Counts);
 
   /// Return the maximum of all known function counts.
-  uint64_t getMaximumFunctionCount() { return Summary->getMaxFunctionCount(); }
+  uint64_t getMaximumFunctionCount(bool IsCS) {
+    if (IsCS) {
+      assert(CS_Summary && "No context sensitive profile summary");
+      return CS_Summary->getMaxFunctionCount();
+    } else {
+      assert(Summary && "No profile summary");
+      return Summary->getMaxFunctionCount();
+    }
+  }
 
   /// Factory method to create an indexed reader.
   static Expected<std::unique_ptr<IndexedInstrProfReader>>
   create(const Twine &Path, const Twine &RemappingPath = "");
 
   static Expected<std::unique_ptr<IndexedInstrProfReader>>
   create(std::unique_ptr<MemoryBuffer> Buffer,
          std::unique_ptr<MemoryBuffer> RemappingBuffer = nullptr);
 
   // Used for testing purpose only.
   void setValueProfDataEndianness(support::endianness Endianness) {
     Index->setValueProfDataEndianness(Endianness);
   }
 
   // See description in the base class. This interface is designed
   // to be used by llvm-profdata (for dumping). Avoid using this when
   // the client is the compiler.
   InstrProfSymtab &getSymtab() override;
-  ProfileSummary &getSummary() { return *(Summary.get()); }
+  ProfileSummary &getSummary(bool IsCS) {
+    if (IsCS) {
+      assert(CS_Summary && "No context sensitive summary");
+      return *(CS_Summary.get());
+    } else {
+      assert(Summary && "No profile summary");
+      return *(Summary.get());
+    }
+  }
 };
 
 } // end namespace llvm
 
 #endif // LLVM_PROFILEDATA_INSTRPROFREADER_H

include/llvm/ProfileData/InstrProfWriter.h

 /// Writer for instrumentation based profile data.
 class InstrProfRecordWriterTrait;
 class ProfOStream;
 class raw_fd_ostream;
 
 class InstrProfWriter {
 public:
   using ProfilingData = SmallDenseMap<uint64_t, InstrProfRecord>;
-  enum ProfKind { PF_Unknown = 0, PF_FE, PF_IRLevel };
+  enum ProfKind { PF_Unknown = 0, PF_FE, PF_IRLevel, PF_IRLevelWithCS };
 
 private:
   bool Sparse;
   StringMap<ProfilingData> FunctionData;
   ProfKind ProfileKind = PF_Unknown;
   // Use raw pointer here for the incomplete type object.
   InstrProfRecordWriterTrait *InfoObj;
 
public:
   static void writeRecordInText(StringRef Name, uint64_t Hash,
                                 const InstrProfRecord &Counters,
                                 InstrProfSymtab &Symtab, raw_fd_ostream &OS);
 
   /// Write the profile, returning the raw data. For testing.
   std::unique_ptr<MemoryBuffer> writeBuffer();
 
   /// Set the ProfileKind. Report error if mixing FE and IR level profiles.
-  Error setIsIRLevelProfile(bool IsIRLevel) {
+  Error setIsIRLevelProfile(bool IsIRLevel, bool WithCS) {
     if (ProfileKind == PF_Unknown) {
-      ProfileKind = IsIRLevel ? PF_IRLevel: PF_FE;
+      if (IsIRLevel)
+        ProfileKind = WithCS ? PF_IRLevelWithCS : PF_IRLevel;
+      else
+        ProfileKind = PF_FE;
       return Error::success();
     }
-    return (IsIRLevel == (ProfileKind == PF_IRLevel))
-               ? Error::success()
-               : make_error<InstrProfError>(
-                     instrprof_error::unsupported_version);
+
+    if (((ProfileKind != PF_FE) && !IsIRLevel) ||
+        ((ProfileKind == PF_FE) && IsIRLevel))
+      return make_error<InstrProfError>(instrprof_error::unsupported_version);
+
+    // Promote to PF_IRLevelWithCS if WithCS is true;
+    if (ProfileKind == PF_IRLevel && WithCS)
+      ProfileKind = PF_IRLevelWithCS;
+
+    return Error::success();
   }
 
   // Internal interface for testing purpose only.
   void setValueProfDataEndianness(support::endianness Endianness);
   void setOutputSparse(bool Sparse);
 
 private:
   void addRecord(StringRef Name, uint64_t Hash, InstrProfRecord &&I,
                  uint64_t Weight, function_ref<void(Error)> Warn);
   bool shouldEncodeData(const ProfilingData &PD);
   void writeImpl(ProfOStream &OS);
 };
 
 } // end namespace llvm
 
 #endif // LLVM_PROFILEDATA_INSTRPROFWRITER_H

include/llvm/Transforms/IPO/PassManagerBuilder.h

public:
   bool MergeFunctions;
   bool PrepareForLTO;
   bool PrepareForThinLTO;
   bool PerformThinLTO;
   bool DivergentTarget;
 
   /// Enable profile instrumentation pass.
   bool EnablePGOInstrGen;
+  /// Enable profile context sensitive instrumentation pass.
+  bool EnablePGOCSInstrGen;
+  /// Enable profile context sensitive profile use pass.
+  bool EnablePGOCSInstrUse;
   /// Profile data file name that the instrumentation will be written to.
   std::string PGOInstrGen;
   /// Path of the profile data file.
   std::string PGOInstrUse;
   /// Path of the sample Profile data file.
   std::string PGOSampleUse;
 
 private:
public:
   void addExtension(ExtensionPointTy Ty, ExtensionFn Fn);
 
 private:
   void addExtensionsToPM(ExtensionPointTy ETy,
                          legacy::PassManagerBase &PM) const;
   void addInitialAliasAnalysisPasses(legacy::PassManagerBase &PM) const;
   void addLTOOptimizationPasses(legacy::PassManagerBase &PM);
   void addLateLTOOptimizationPasses(legacy::PassManagerBase &PM);
-  void addPGOInstrPasses(legacy::PassManagerBase &MPM);
+  void addPGOInstrPasses(legacy::PassManagerBase &MPM, bool IsCS);
   void addFunctionSimplificationPasses(legacy::PassManagerBase &MPM);
   void addInstructionCombiningPass(legacy::PassManagerBase &MPM) const;
 
 public:
   /// populateFunctionPassManager - This fills in the function pass manager,
   /// which is expected to be run on each function immediately as it is
   /// generated.  The idea is to reduce the size of the IR in memory.
   void populateFunctionPassManager(legacy::FunctionPassManager &FPM);

include/llvm/Transforms/Instrumentation.h

struct GCOVOptions {
   // Regexes separated by a semi-colon to filter the files to not instrument.
   std::string Exclude;
 };
 
 ModulePass *createGCOVProfilerPass(const GCOVOptions &Options =
                                    GCOVOptions::getDefault());
 
 // PGO Instrumention
-ModulePass *createPGOInstrumentationGenLegacyPass();
+ModulePass *createPGOInstrumentationGenLegacyPass(bool IsCS = false);
 ModulePass *
-createPGOInstrumentationUseLegacyPass(StringRef Filename = StringRef(""));
+createPGOInstrumentationUseLegacyPass(StringRef Filename = StringRef(""),
+                                      bool IsCS = false);
+ModulePass *createPGOInstrumentationGenCreateVarLegacyPass(
+    StringRef CSInstrName = StringRef(""));
 ModulePass *createPGOIndirectCallPromotionLegacyPass(bool InLTO = false,
                                                      bool SamplePGO = false);
 FunctionPass *createPGOMemOPSizeOptLegacyPass();
 
 // The pgo-specific indirect call promotion function declared below is used by
 // the pgo-driven indirect call promotion and sample profile passes. It's a
 // wrapper around llvm::promoteCall, et al. that additionally computes !prof
 // metadata. We place it in a pgo namespace so it's not confused with the
struct InstrProfOptions {
   bool NoRedZone = false;
 
   // Do counter register promotion
   bool DoCounterPromotion = false;
 
   // Use atomic profile counter increments.
   bool Atomic = false;
 
+  // Use BFI to guide register promotion
+  bool UseBFIInPromotion = false;
+
   // Name of the profile file to use as output
   std::string InstrProfileOutput;
 
   InstrProfOptions() = default;
 };
 
 /// Insert frontend instrumentation based profiling.
 ModulePass *createInstrProfilingLegacyPass(
-    const InstrProfOptions &Options = InstrProfOptions());
+    const InstrProfOptions &Options = InstrProfOptions(), bool IsCS = false);
 
 // Insert AddressSanitizer (address sanity checking) instrumentation
 FunctionPass *createAddressSanitizerFunctionPass(bool CompileKernel = false,
                                                  bool Recover = false,
                                                  bool UseAfterScope = false);
 ModulePass *createAddressSanitizerModulePass(bool CompileKernel = false,
                                              bool Recover = false,
                                              bool UseGlobalsGC = true,

include/llvm/Transforms/Instrumentation/InstrProfiling.h

 using LoadStorePair = std::pair<Instruction *, Instruction *>;
 
 /// Instrumentation based profiling lowering pass. This pass lowers
 /// the profile instrumented code generated by FE or the IR based
 /// instrumentation pass.
 class InstrProfiling : public PassInfoMixin<InstrProfiling> {
 public:
   InstrProfiling() = default;
-  InstrProfiling(const InstrProfOptions &Options) : Options(Options) {}
+  InstrProfiling(const InstrProfOptions &Options, bool IsCS)
+      : Options(Options), IsCS(IsCS) {}
 
   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
   bool run(Module &M, const TargetLibraryInfo &TLI);
 
 private:
   InstrProfOptions Options;
   Module *M;
   Triple TT;
   const TargetLibraryInfo *TLI;
   struct PerFunctionProfileData {
     uint32_t NumValueSites[IPVK_Last + 1];
     GlobalVariable *RegionCounters = nullptr;
     GlobalVariable *DataVar = nullptr;
 
     PerFunctionProfileData() {
       memset(NumValueSites, 0, sizeof(uint32_t) * (IPVK_Last + 1));
     }
   };
   DenseMap<GlobalVariable *, PerFunctionProfileData> ProfileDataMap;
   std::vector<GlobalValue *> UsedVars;
   std::vector<GlobalVariable *> ReferencedNames;
   GlobalVariable *NamesVar;
   size_t NamesSize;
 
+  // Is this lowering for the context-sensitive instrumentation.
+  bool IsCS;
+
   // vector of counter load/store pairs to be register promoted.
   std::vector<LoadStorePair> PromotionCandidates;
 
   // The start value of precise value profile range for memory intrinsic sizes.
   int64_t MemOPSizeRangeStart;
   // The end value of precise value profile range for memory intrinsic sizes.
   int64_t MemOPSizeRangeLast;
 

include/llvm/Transforms/Instrumentation/PGOInstrumentation.h

 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_TRANSFORMS_PGOINSTRUMENTATION_H
 #define LLVM_TRANSFORMS_PGOINSTRUMENTATION_H
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/ProfileData/InstrProf.h"
 #include <cstdint>
 #include <string>
 
 namespace llvm {
 
 class Function;
 class Instruction;
 class Module;
 
 /// The instrumentation (profile-instr-gen) pass for IR based PGO.
+class PGOInstrumentationGenCreateVar
+    : public PassInfoMixin<PGOInstrumentationGenCreateVar> {
+public:
+  PGOInstrumentationGenCreateVar(std::string CSInstrName = "")
+      : CSInstrName(CSInstrName) {}
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM) {
+    createProfileNameVar(M, CSInstrName);
+    createIRLevelProfileFlagVar(M, /* IsCS */ true);
+    return PreservedAnalyses::all();
+  }
+
+private:
+  std::string CSInstrName;
+};
+
+/// The instrumentation (profile-instr-gen) pass for IR based PGO.
 class PGOInstrumentationGen : public PassInfoMixin<PGOInstrumentationGen> {
 public:
+  PGOInstrumentationGen(bool IsCS = false) : IsCS(IsCS) {}
   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
+
+private:
+  // If this is a context sensitive instrumentation.
+  bool IsCS;
 };
 
 /// The profile annotation (profile-instr-use) pass for IR based PGO.
 class PGOInstrumentationUse : public PassInfoMixin<PGOInstrumentationUse> {
 public:
   PGOInstrumentationUse(std::string Filename = "",
-                        std::string RemappingFilename = "");
+                        std::string RemappingFilename = "", bool IsCS = false);
 
   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
 
 private:
   std::string ProfileFileName;
   std::string ProfileRemappingFileName;
+  // If this is a context sensitive instrumentation.
+  bool IsCS;
 };
 
 /// The indirect function call promotion pass.
 class PGOIndirectCallPromotion : public PassInfoMixin<PGOIndirectCallPromotion> {
 public:
   PGOIndirectCallPromotion(bool IsInLTO = false, bool SamplePGO = false)
       : InLTO(IsInLTO), SamplePGO(SamplePGO) {}
 

lib/Analysis/ProfileSummaryInfo.cpp

 // The profile summary metadata may be attached either by the frontend or by
 // any backend passes (IR level instrumentation, for example). This method
 // checks if the Summary is null and if so checks if the summary metadata is now
 // available in the module and parses it to get the Summary object. Returns true
 // if a valid Summary is available.
 bool ProfileSummaryInfo::computeSummary() {
   if (Summary)
     return true;
-  auto *SummaryMD = M.getProfileSummary();
+  // First try to get context sensitive ProfileSummary.
+  auto *SummaryMD = M.getProfileSummary(ProfileSummary::PSK_CSInstr);
+  if (SummaryMD) {
+    Summary.reset(ProfileSummary::getFromMD(SummaryMD));
+    return true;
+  }
+  // This will actually return PSK_Instr or PSK_Sample summary.
+  SummaryMD = M.getProfileSummary(ProfileSummary::PSK_Instr);
   if (!SummaryMD)
     return false;
   Summary.reset(ProfileSummary::getFromMD(SummaryMD));
   return true;
 }
 
 Optional<uint64_t>
 ProfileSummaryInfo::getProfileCount(const Instruction *Inst,

lib/IR/Module.cpp

 void Module::setCodeModel(CodeModel::Model CL) {
   // Linking object files with different code models is undefined behavior
   // because the compiler would have to generate additional code (to span
   // longer jumps) if a larger code model is used with a smaller one.
   // Therefore we will treat attempts to mix code models as an error.
   addModuleFlag(ModFlagBehavior::Error, "Code Model", CL);
 }
 
-void Module::setProfileSummary(Metadata *M) {
+void Module::setProfileSummary(Metadata *M, ProfileSummary::Kind Kind) {
+  if (Kind == ProfileSummary::PSK_CSInstr)
+    addModuleFlag(ModFlagBehavior::Error, "CSProfileSummary", M);
+  else
     addModuleFlag(ModFlagBehavior::Error, "ProfileSummary", M);
 }
 
-Metadata *Module::getProfileSummary() {
+Metadata *Module::getProfileSummary(ProfileSummary::Kind Kind) {
+  if (Kind == ProfileSummary::PSK_CSInstr)
+    return getModuleFlag("CSProfileSummary");
+  else
     return getModuleFlag("ProfileSummary");
 }
 
 void Module::setOwnedMemoryBuffer(std::unique_ptr<MemoryBuffer> MB) {
   OwnedMemoryBuffer = std::move(MB);
 }
 
 bool Module::getRtLibUseGOT() const {
   auto *Val = cast_or_null<ConstantAsMetadata>(getModuleFlag("RtLibUseGOT"));

lib/IR/ProfileSummary.cpp

 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Type.h"
 #include "llvm/Support/Casting.h"
 
 using namespace llvm;
 
-const char *ProfileSummary::KindStr[2] = {"InstrProf", "SampleProfile"};
-
 // Return an MDTuple with two elements. The first element is a string Key and
 // the second is a uint64_t Value.
 static Metadata *getKeyValMD(LLVMContext &Context, const char *Key,
                              uint64_t Val) {
   Type *Int64Ty = Type::getInt64Ty(Context);
   Metadata *Ops[2] = {MDString::get(Context, Key),
                       ConstantAsMetadata::get(ConstantInt::get(Int64Ty, Val))};
   return MDTuple::get(Context, Ops);

 }
 
 // This returns an MDTuple representing this ProfileSummary object. The first
 // entry of this tuple is another MDTuple of two elements: a string
 // "ProfileFormat" and a string representing the format ("InstrProf" or
 // "SampleProfile"). The rest of the elements of the outer MDTuple are specific
 // to the kind of profile summary as returned by getFormatSpecificMD.
 Metadata *ProfileSummary::getMD(LLVMContext &Context) {
+  const char *KindStr[3] = {"InstrProf", "CSInstrProf", "SampleProfile"};
   Metadata *Components[] = {
     getKeyValMD(Context, "ProfileFormat", KindStr[PSK]),
     getKeyValMD(Context, "TotalCount", getTotalCount()),
     getKeyValMD(Context, "MaxCount", getMaxCount()),
     getKeyValMD(Context, "MaxInternalCount", getMaxInternalCount()),
     getKeyValMD(Context, "MaxFunctionCount", getMaxFunctionCount()),
     getKeyValMD(Context, "NumCounts", getNumCounts()),
     getKeyValMD(Context, "NumFunctions", getNumFunctions()),
ProfileSummary *ProfileSummary::getFromMD(Metadata *MD) {
   auto &FormatMD = Tuple->getOperand(0);
   ProfileSummary::Kind SummaryKind;
   if (isKeyValuePair(dyn_cast_or_null<MDTuple>(FormatMD), "ProfileFormat",
                      "SampleProfile"))
     SummaryKind = PSK_Sample;
   else if (isKeyValuePair(dyn_cast_or_null<MDTuple>(FormatMD), "ProfileFormat",
                           "InstrProf"))
     SummaryKind = PSK_Instr;
+  else if (isKeyValuePair(dyn_cast_or_null<MDTuple>(FormatMD), "ProfileFormat",
+                          "CSInstrProf"))
+    SummaryKind = PSK_CSInstr;
   else
     return nullptr;
 
   uint64_t NumCounts, TotalCount, NumFunctions, MaxFunctionCount, MaxCount,
       MaxInternalCount;
   if (!getVal(dyn_cast<MDTuple>(Tuple->getOperand(1)), "TotalCount",
               TotalCount))
     return nullptr;

lib/LTO/LTOBackend.cpp

createTargetMachine(Config &Conf, const Target *TheTarget, Module &M) {
   else
     CodeModel = M.getCodeModel();
 
   return std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(
       TheTriple, Conf.CPU, Features.getString(), Conf.Options, RelocModel,
       CodeModel, Conf.CGOptLevel));
 }
 
 static void runNewPMPasses(Config &Conf, Module &Mod, TargetMachine *TM,
                            unsigned OptLevel, bool IsThinLTO,
                            ModuleSummaryIndex *ExportSummary,
                            const ModuleSummaryIndex *ImportSummary) {
   Optional<PGOOptions> PGOOpt;
   if (!Conf.SampleProfile.empty())
-    PGOOpt = PGOOptions("", "", Conf.SampleProfile, Conf.ProfileRemapping,
-                        false, true);
+    PGOOpt = PGOOptions(Conf.SampleProfile, "", Conf.ProfileRemapping,
+                        PGOOptions::SampleUse, PGOOptions::NoCSAction, true);
+  else if (Conf.RunCSIRInstr) {
+    PGOOpt = PGOOptions("", Conf.CSIRProfile, Conf.ProfileRemapping,
+                        PGOOptions::IRUse, PGOOptions::CSIRInstr);
+  } else if (!Conf.CSIRProfile.empty()) {
+    PGOOpt = PGOOptions(Conf.CSIRProfile, "", Conf.ProfileRemapping,
+                        PGOOptions::IRUse, PGOOptions::CSIRUse);
+  }
 
   PassBuilder PB(TM, PGOOpt);
   AAManager AA;
 
   // Parse a custom AA pipeline if asked to.
   if (auto Err = PB.parseAAPipeline(AA, "default"))
     report_fatal_error("Error parsing default AA pipeline");
 
static void runOldPMPasses(Config &Conf, Module &Mod, TargetMachine *TM,
   // Unconditionally verify input since it is not verified before this
   // point and has unknown origin.
   PMB.VerifyInput = true;
   PMB.VerifyOutput = !Conf.DisableVerify;
   PMB.LoopVectorize = true;
   PMB.SLPVectorize = true;
   PMB.OptLevel = Conf.OptLevel;
   PMB.PGOSampleUse = Conf.SampleProfile;
+  PMB.EnablePGOCSInstrGen = Conf.RunCSIRInstr;
+  if (!Conf.RunCSIRInstr && !Conf.CSIRProfile.empty()) {
+    PMB.EnablePGOCSInstrUse = true;
+    PMB.PGOInstrUse = Conf.CSIRProfile;
+  }
   if (IsThinLTO)
     PMB.populateThinLTOPassManager(passes);
   else
     PMB.populateLTOPassManager(passes);
   passes.run(Mod);
 }
 
 bool opt(Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,

lib/Passes/PassBuilder.cpp

PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
 
   if (!isOptimizingForSize(Level))
     FPM.addPass(LibCallsShrinkWrapPass());
 
   invokePeepholeEPCallbacks(FPM, Level);
 
   // For PGO use pipeline, try to optimize memory intrinsics such as memcpy
   // using the size value profile. Don't perform this when optimizing for size.
-  if (PGOOpt && !PGOOpt->ProfileUseFile.empty() &&
+  if (PGOOpt && PGOOpt->Action == PGOOptions::IRUse &&
       !isOptimizingForSize(Level))
     FPM.addPass(PGOMemOPSizeOpt());
 
   FPM.addPass(TailCallElimPass());
   FPM.addPass(SimplifyCFGPass());
 
   // Form canonically associated expression trees, and simplify the trees using
   // basic mathematical properties. For example, this will form (nearly)
PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
 
   for (auto &C : LateLoopOptimizationsEPCallbacks)
     C(LPM2, Level);
 
   LPM2.addPass(LoopDeletionPass());
   // Do not enable unrolling in PreLinkThinLTO phase during sample PGO
   // because it changes IR to makes profile annotation in back compile
   // inaccurate.
-  if (Phase != ThinLTOPhase::PreLink ||
-      !PGOOpt || PGOOpt->SampleProfileFile.empty())
+  if (Phase != ThinLTOPhase::PreLink || !PGOOpt ||
+      PGOOpt->Action != PGOOptions::SampleUse)
     LPM2.addPass(LoopFullUnrollPass(Level));
 
   for (auto &C : LoopOptimizerEndEPCallbacks)
     C(LPM2, Level);
 
   // We provide the opt remark emitter pass for LICM to use. We only need to do
   // this once as it is immutable.
   FPM.addPass(RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   // Finally, do an expensive DCE pass to catch all the dead code exposed by
   // the simplifications and basic cleanup after all the simplifications.
   FPM.addPass(ADCEPass());
   FPM.addPass(SimplifyCFGPass());
   FPM.addPass(InstCombinePass());
   invokePeepholeEPCallbacks(FPM, Level);
 
   if (EnableCHR && Level == O3 && PGOOpt &&
-      (!PGOOpt->ProfileUseFile.empty() || !PGOOpt->SampleProfileFile.empty()))
+      (PGOOpt->Action == PGOOptions::IRUse ||
+       PGOOpt->Action == PGOOptions::SampleUse))
     FPM.addPass(ControlHeightReductionPass());
 
   return FPM;
 }
 
 void PassBuilder::addPGOInstrPasses(ModulePassManager &MPM, bool DebugLogging,
                                     PassBuilder::OptimizationLevel Level,
-                                    bool RunProfileGen,
-                                    std::string ProfileGenFile,
-                                    std::string ProfileUseFile,
+                                    bool RunProfileGen, bool IsCS,
+                                    std::string ProfileFile,
                                     std::string ProfileRemappingFile) {
   // Generally running simplification passes and the inliner with an high
   // threshold results in smaller executables, but there may be cases where
   // the size grows, so let's be conservative here and skip this simplification
   // at -Os/Oz.
-  if (!isOptimizingForSize(Level)) {
+  if (!isOptimizingForSize(Level) && !IsCS) {
     InlineParams IP;
 
     // In the old pass manager, this is a cl::opt. Should still this be one?
     IP.DefaultThreshold = 75;
 
     // FIXME: The hint threshold has the same value used by the regular inliner.
     // This should probably be lowered after performance testing.
     // FIXME: this comment is cargo culted from the old pass manager, revisit).
void PassBuilder::addPGOInstrPasses(ModulePassManager &MPM, bool DebugLogging,
   }
 
   // Delete anything that is now dead to make sure that we don't instrument
   // dead code. Instrumentation can end up keeping dead code around and
   // dramatically increase code size.
   MPM.addPass(GlobalDCEPass());
 
   if (RunProfileGen) {
-    MPM.addPass(PGOInstrumentationGen());
+    MPM.addPass(PGOInstrumentationGen(IsCS));
 
     FunctionPassManager FPM;
     FPM.addPass(
         createFunctionToLoopPassAdaptor(LoopRotatePass(), DebugLogging));
     MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
 
     // Add the profile lowering pass.
     InstrProfOptions Options;
-    if (!ProfileGenFile.empty())
-      Options.InstrProfileOutput = ProfileGenFile;
+    if (!ProfileFile.empty())
+      Options.InstrProfileOutput = ProfileFile;
     Options.DoCounterPromotion = true;
-    MPM.addPass(InstrProfiling(Options));
-  }
-
-  if (!ProfileUseFile.empty())
-    MPM.addPass(PGOInstrumentationUse(ProfileUseFile, ProfileRemappingFile));
+    Options.UseBFIInPromotion = IsCS;
+    MPM.addPass(InstrProfiling(Options, IsCS));
+  } else if (!ProfileFile.empty())
+    MPM.addPass(PGOInstrumentationUse(ProfileFile, ProfileRemappingFile, IsCS));
 }
 
 static InlineParams
 getInlineParamsFromOptLevel(PassBuilder::OptimizationLevel Level) {
   auto O3 = PassBuilder::O3;
   unsigned OptLevel = Level > O3 ? 2 : Level;
   unsigned SizeLevel = Level > O3 ? Level - O3 : 0;
   return getInlineParams(OptLevel, SizeLevel);
if (Level == O3)
     EarlyFPM.addPass(CallSiteSplittingPass());
 
   // In SamplePGO ThinLTO backend, we need instcombine before profile annotation
   // to convert bitcast to direct calls so that they can be inlined during the
   // profile annotation prepration step.
   // More details about SamplePGO design can be found in:
   // https://research.google.com/pubs/pub45290.html
   // FIXME: revisit how SampleProfileLoad/Inliner/ICP is structured.
-  if (PGOOpt && !PGOOpt->SampleProfileFile.empty() &&
+  if (PGOOpt && PGOOpt->Action == PGOOptions::SampleUse &&
       Phase == ThinLTOPhase::PostLink)
     EarlyFPM.addPass(InstCombinePass());
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(EarlyFPM)));
 
-  if (PGOOpt && !PGOOpt->SampleProfileFile.empty()) {
+  if (PGOOpt && PGOOpt->Action == PGOOptions::SampleUse) {
     // Annotate sample profile right after early FPM to ensure freshness of
     // the debug info.
     // In ThinLTO mode, when flattened profile is used, all the available
     // profile information will be annotated in PreLink phase so there is
     // no need to load the profile again in PostLink.
     if (!(FlattenedProfileUsed && Phase == ThinLTOPhase::PostLink))
-      MPM.addPass(SampleProfileLoaderPass(PGOOpt->SampleProfileFile,
+      MPM.addPass(SampleProfileLoaderPass(PGOOpt->ProfileFile,
                                           PGOOpt->ProfileRemappingFile,
                                           Phase == ThinLTOPhase::PreLink));
     // Do not invoke ICP in the ThinLTOPrelink phase as it makes it hard
     // for the profile annotation to be accurate in the ThinLTO backend.
     if (Phase != ThinLTOPhase::PreLink)
       // We perform early indirect call promotion here, before globalopt.
       // This is important for the ThinLTO backend phase because otherwise
       // imported available_externally functions look unreferenced and are
PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
   GlobalCleanupPM.addPass(InstCombinePass());
   invokePeepholeEPCallbacks(GlobalCleanupPM, Level);
 
   GlobalCleanupPM.addPass(SimplifyCFGPass());
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(GlobalCleanupPM)));
 
   // Add all the requested passes for instrumentation PGO, if requested.
   if (PGOOpt && Phase != ThinLTOPhase::PostLink &&
-      (!PGOOpt->ProfileGenFile.empty() || !PGOOpt->ProfileUseFile.empty())) {
-    addPGOInstrPasses(MPM, DebugLogging, Level, PGOOpt->RunProfileGen,
-                      PGOOpt->ProfileGenFile, PGOOpt->ProfileUseFile,
+      (PGOOpt->Action == PGOOptions::IRInstr ||
+       PGOOpt->Action == PGOOptions::IRUse)) {
+    addPGOInstrPasses(MPM, DebugLogging, Level,
+                      /* RunProfileGen */ PGOOpt->Action == PGOOptions::IRInstr,
+                      /* IsCS */ false, PGOOpt->ProfileFile,
                       PGOOpt->ProfileRemappingFile);
     MPM.addPass(PGOIndirectCallPromotion(false, false));
   }
+  if (PGOOpt && Phase != ThinLTOPhase::PostLink &&
+      PGOOpt->CSAction == PGOOptions::CSIRInstr)
+    MPM.addPass(PGOInstrumentationGenCreateVar(PGOOpt->CSProfileGenFile));
 
   // Synthesize function entry counts for non-PGO compilation.
   if (EnableSyntheticCounts && !PGOOpt)
     MPM.addPass(SyntheticCountsPropagation());
 
   // Require the GlobalsAA analysis for the module so we can query it within
   // the CGSCC pipeline.
   MPM.addPass(RequireAnalysisPass<GlobalsAA, Module>());
PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
   // invoke or a call.
 
   // Run the inliner first. The theory is that we are walking bottom-up and so
   // the callees have already been fully optimized, and we want to inline them
   // into the callers so that our optimizations can reflect that.
   // For PreLinkThinLTO pass, we disable hot-caller heuristic for sample PGO
   // because it makes profile annotation in the backend inaccurate.
   InlineParams IP = getInlineParamsFromOptLevel(Level);
-  if (Phase == ThinLTOPhase::PreLink &&
-      PGOOpt && !PGOOpt->SampleProfileFile.empty())
+  if (Phase == ThinLTOPhase::PreLink && PGOOpt &&
+      PGOOpt->Action == PGOOptions::SampleUse)
     IP.HotCallSiteThreshold = 0;
   MainCGPipeline.addPass(InlinerPass(IP));
 
   // Now deduce any function attributes based in the current code.
   MainCGPipeline.addPass(PostOrderFunctionAttrsPass());
 
   // When at O3 add argument promotion to the pass pipeline.
   // FIXME: It isn't at all clear why this should be limited to O3.
PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
   // in postorder (or bottom-up).
   MPM.addPass(
       createModuleToPostOrderCGSCCPassAdaptor(createDevirtSCCRepeatedPass(
           std::move(MainCGPipeline), MaxDevirtIterations)));
 
   return MPM;
 }
 
-ModulePassManager
-PassBuilder::buildModuleOptimizationPipeline(OptimizationLevel Level,
-                                             bool DebugLogging) {
+ModulePassManager PassBuilder::buildModuleOptimizationPipeline(
+    OptimizationLevel Level, bool DebugLogging, bool LTOPreLink) {
   ModulePassManager MPM(DebugLogging);
 
   // Optimize globals now that the module is fully simplified.
   MPM.addPass(GlobalOptPass());
   MPM.addPass(GlobalDCEPass());
 
   // Run partial inlining pass to partially inline functions that have
   // large bodies.
ModulePassManager PassBuilder::buildModuleOptimizationPipeline(
   // running remaining passes on the eliminated functions.
   MPM.addPass(EliminateAvailableExternallyPass());
 
   // Do RPO function attribute inference across the module to forward-propagate
   // attributes where applicable.
   // FIXME: Is this really an optimization rather than a canonicalization?
   MPM.addPass(ReversePostOrderFunctionAttrsPass());
 
+  // Do a post inline PGO instrumentation and use pass. This is a context
+  // sensitive PGO pass. We don't want to do this in LTOPreLink phrase as
+  // cross-module inline has not been done yet. The context sensitive
+  // instrumentation is after all the inlines are done.
+  if (!LTOPreLink && PGOOpt) {
+    if (PGOOpt->CSAction == PGOOptions::CSIRInstr)
+      addPGOInstrPasses(MPM, DebugLogging, Level, /* RunProfileGen */ true,
+                        /* IsCS */ true, PGOOpt->CSProfileGenFile,
+                        PGOOpt->ProfileRemappingFile);
+    else if (PGOOpt->CSAction == PGOOptions::CSIRUse)
+      addPGOInstrPasses(MPM, DebugLogging, Level, /* RunProfileGen */ false,
+                        /* IsCS */ true, PGOOpt->ProfileFile,
+                        PGOOpt->ProfileRemappingFile);
+  }
+
   // Re-require GloblasAA here prior to function passes. This is particularly
   // useful as the above will have inlined, DCE'ed, and function-attr
   // propagated everything. We should at this point have a reasonably minimal
   // and richly annotated call graph. By computing aliasing and mod/ref
   // information for all local globals here, the late loop passes and notably
   // the vectorizer will be able to use them to help recognize vectorizable
   // memory operations.
   MPM.addPass(RequireAnalysisPass<GlobalsAA, Module>());
ModulePassManager PassBuilder::buildModuleOptimizationPipeline(
   MPM.addPass(GlobalDCEPass());
   MPM.addPass(ConstantMergePass());
 
   return MPM;
 }
 
 ModulePassManager
 PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
-                                           bool DebugLogging) {
+                                           bool DebugLogging, bool LTOPreLink) {
   assert(Level != O0 && "Must request optimizations for the default pipeline!");
 
   ModulePassManager MPM(DebugLogging);
 
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
   // Apply module pipeline start EP callback.
   for (auto &C : PipelineStartEPCallbacks)
     C(MPM);
 
   if (PGOOpt && PGOOpt->SamplePGOSupport)
     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
 
   // Add the core simplification pipeline.
   MPM.addPass(buildModuleSimplificationPipeline(Level, ThinLTOPhase::None,
                                                 DebugLogging));
 
   // Now add the optimization pipeline.
-  MPM.addPass(buildModuleOptimizationPipeline(Level, DebugLogging));
+  MPM.addPass(buildModuleOptimizationPipeline(Level, DebugLogging, LTOPreLink));
 
   return MPM;
 }
 
 ModulePassManager
 PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level,
                                                 bool DebugLogging) {
   assert(Level != O0 && "Must request optimizations for the default pipeline!");
ModulePassManager PassBuilder::buildThinLTODefaultPipeline(
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
   // During the ThinLTO backend phase we perform early indirect call promotion
   // here, before globalopt. Otherwise imported available_externally functions
   // look unreferenced and are removed.
   // FIXME: move this into buildModuleSimplificationPipeline to merge the logic
   //        with SamplePGO.
-  if (!PGOOpt || PGOOpt->SampleProfileFile.empty())
+  if (!PGOOpt || PGOOpt->Action != PGOOptions::SampleUse)
     MPM.addPass(PGOIndirectCallPromotion(true /* InLTO */,
                                          false /* SamplePGO */));
 
   // Add the core simplification pipeline.
   MPM.addPass(buildModuleSimplificationPipeline(Level, ThinLTOPhase::PostLink,
                                                 DebugLogging));
 
   // Now add the optimization pipeline.
   MPM.addPass(buildModuleOptimizationPipeline(Level, DebugLogging));
 
   return MPM;
 }
 
 ModulePassManager
 PassBuilder::buildLTOPreLinkDefaultPipeline(OptimizationLevel Level,
                                             bool DebugLogging) {
   assert(Level != O0 && "Must request optimizations for the default pipeline!");
   // FIXME: We should use a customized pre-link pipeline!
-  return buildPerModuleDefaultPipeline(Level, DebugLogging);
+  return buildPerModuleDefaultPipeline(Level, DebugLogging,
+                                       /* LTOPreLink */ true);
 }
 
 ModulePassManager
 PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level, bool DebugLogging,
                                      ModuleSummaryIndex *ExportSummary) {
   assert(Level != O0 && "Must request optimizations for the default pipeline!");
   ModulePassManager MPM(DebugLogging);
 
-  if (PGOOpt && !PGOOpt->SampleProfileFile.empty()) {
+  if (PGOOpt && PGOOpt->Action == PGOOptions::SampleUse) {
     // Load sample profile before running the LTO optimization pipeline.
-    MPM.addPass(SampleProfileLoaderPass(PGOOpt->SampleProfileFile,
+    MPM.addPass(SampleProfileLoaderPass(PGOOpt->ProfileFile,
                                         PGOOpt->ProfileRemappingFile,
                                         false /* ThinLTOPhase::PreLink */));
   }
 
   // Remove unused virtual tables to improve the quality of code generated by
   // whole-program devirtualization and bitset lowering.
   MPM.addPass(GlobalDCEPass());
 
if (Level > 1) {
     EarlyFPM.addPass(CallSiteSplittingPass());
     MPM.addPass(createModuleToFunctionPassAdaptor(std::move(EarlyFPM)));
 
     // Indirect call promotion. This should promote all the targets that are
     // left by the earlier promotion pass that promotes intra-module targets.
     // This two-step promotion is to save the compile time. For LTO, it should
     // produce the same result as if we only do promotion here.
     MPM.addPass(PGOIndirectCallPromotion(
-        true /* InLTO */, PGOOpt && !PGOOpt->SampleProfileFile.empty()));
+        true /* InLTO */, PGOOpt && PGOOpt->Action == PGOOptions::SampleUse));
     // Propagate constants at call sites into the functions they call.  This
     // opens opportunities for globalopt (and inlining) by substituting function
     // pointers passed as arguments to direct uses of functions.
    MPM.addPass(IPSCCPPass());
 
    // Attach metadata to indirect call sites indicating the set of functions
    // they may target at run-time. This should follow IPSCCP.
    MPM.addPass(CalledValuePropagationPass());
PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level, bool DebugLogging,
 
   FunctionPassManager FPM(DebugLogging);
   // The IPO Passes may leave cruft around. Clean up after them.
   FPM.addPass(InstCombinePass());
   invokePeepholeEPCallbacks(FPM, Level);
 
   FPM.addPass(JumpThreadingPass());
 
+  // Do a post inline PGO instrumentation and use pass. This is a context
+  // sensitive PGO pass.
+  if (PGOOpt) {
+    if (PGOOpt->CSAction == PGOOptions::CSIRInstr)
+      addPGOInstrPasses(MPM, DebugLogging, Level, /* RunProfileGen */ true,
+                        /* IsCS */ true, PGOOpt->CSProfileGenFile,
+                        PGOOpt->ProfileRemappingFile);
+    else if (PGOOpt->CSAction == PGOOptions::CSIRUse)
+      addPGOInstrPasses(MPM, DebugLogging, Level, /* RunProfileGen */ false,
+                        /* IsCS */ true, PGOOpt->ProfileFile,
+                        PGOOpt->ProfileRemappingFile);
+  }
+
   // Break up allocas
   FPM.addPass(SROA());
 
   // Run a few AA driver optimizations here and now to cleanup the code.
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
 
   MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
               PostOrderFunctionAttrsPass()));

lib/ProfileData/InstrProf.cpp

if (Pos != std::string::npos) {
       if (Pos < MemOPSizeRange.size() - 1)
         MemOPSizeRange.substr(Pos + 1).getAsInteger(10, RangeLast);
     } else
       MemOPSizeRange.getAsInteger(10, RangeLast);
   }
   assert(RangeLast >= RangeStart);
 }
 
+// Create variable for profile name.
+void createProfileNameVar(Module &M, StringRef InstrProfileOutput) {
+  if (InstrProfileOutput.empty())
+    return;
+  Constant *ProfileNameConst =
+      ConstantDataArray::getString(M.getContext(), InstrProfileOutput, true);
+  GlobalVariable *ProfileNameVar = new GlobalVariable(
+      M, ProfileNameConst->getType(), true, GlobalValue::WeakAnyLinkage,
+      ProfileNameConst, INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_NAME_VAR));
+  Triple TT(M.getTargetTriple());
+  if (TT.supportsCOMDAT()) {
+    ProfileNameVar->setLinkage(GlobalValue::ExternalLinkage);
+    ProfileNameVar->setComdat(M.getOrInsertComdat(
+        StringRef(INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_NAME_VAR))));
+  }
+}
+
+// Create a COMDAT variable INSTR_PROF_RAW_VERSION_VAR to make the runtime
+// aware this is an ir_level profile so it can set the version flag.
+void createIRLevelProfileFlagVar(Module &M, bool IsCS) {
+  const StringRef VarName(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR));
+  Type *IntTy64 = Type::getInt64Ty(M.getContext());
+  uint64_t ProfileVersion = (INSTR_PROF_RAW_VERSION | VARIANT_MASK_IR_PROF);
+  if (IsCS)
+    ProfileVersion |= VARIANT_MASK_CSIR_PROF;
+  auto IRLevelVersionVariable = new GlobalVariable(
+      M, IntTy64, true, GlobalValue::WeakAnyLinkage,
+      Constant::getIntegerValue(IntTy64, APInt(64, ProfileVersion)), VarName);
+  IRLevelVersionVariable->setVisibility(GlobalValue::DefaultVisibility);
+  Triple TT(M.getTargetTriple());
+  if (TT.supportsCOMDAT()) {
+    IRLevelVersionVariable->setLinkage(GlobalValue::ExternalLinkage);
+    IRLevelVersionVariable->setComdat(M.getOrInsertComdat(VarName));
+  }
+}
+
 } // end namespace llvm

lib/ProfileData/InstrProfReader.cpp

if (!Line->startswith(":")) {
     IsIRLevelProfile = false;
     return success();
   }
   StringRef Str = (Line)->substr(1);
   if (Str.equals_lower("ir"))
     IsIRInstr = true;
   else if (Str.equals_lower("fe"))
     IsIRInstr = false;
-  else
+  else if (Str.equals_lower("csir")) {
+    IsIRInstr = true;
+    HasCSIRLevelProfile = true;
+  } else
     return error(instrprof_error::bad_header);
 
   ++Line;
   IsIRLevelProfile = IsIRInstr;
   return success();
 }
 
 Error
bool IndexedInstrProfReader::hasFormat(const MemoryBuffer &DataBuffer) {
   uint64_t Magic =
       endian::read<uint64_t, little, aligned>(DataBuffer.getBufferStart());
   // Verify that it's magical.
   return Magic == IndexedInstrProf::Magic;
 }
 
 const unsigned char *
 IndexedInstrProfReader::readSummary(IndexedInstrProf::ProfVersion Version,
-                                    const unsigned char *Cur) {
+                                    const unsigned char *Cur, bool UseCS) {
   using namespace IndexedInstrProf;
   using namespace support;
 
   if (Version >= IndexedInstrProf::Version4) {
     const IndexedInstrProf::Summary *SummaryInLE =
         reinterpret_cast<const IndexedInstrProf::Summary *>(Cur);
     uint64_t NFields =
         endian::byte_swap<uint64_t, little>(SummaryInLE->NumSummaryFields);
for (unsigned I = 0; I < SummarySize / sizeof(uint64_t); I++)
       Dst[I] = endian::byte_swap<uint64_t, little>(Src[I]);
 
     SummaryEntryVector DetailedSummary;
     for (unsigned I = 0; I < SummaryData->NumCutoffEntries; I++) {
       const IndexedInstrProf::Summary::Entry &Ent = SummaryData->getEntry(I);
       DetailedSummary.emplace_back((uint32_t)Ent.Cutoff, Ent.MinBlockCount,
                                    Ent.NumBlocks);
     }
+    std::unique_ptr<llvm::ProfileSummary> &Summary =
+        UseCS ? this->CS_Summary : this->Summary;
+
     // initialize InstrProfSummary using the SummaryData from disk.
-    this->Summary = llvm::make_unique<ProfileSummary>(
-        ProfileSummary::PSK_Instr, DetailedSummary,
-        SummaryData->get(Summary::TotalBlockCount),
+    Summary = llvm::make_unique<ProfileSummary>(
+        UseCS ? ProfileSummary::PSK_CSInstr : ProfileSummary::PSK_Instr,
+        DetailedSummary, SummaryData->get(Summary::TotalBlockCount),
         SummaryData->get(Summary::MaxBlockCount),
         SummaryData->get(Summary::MaxInternalBlockCount),
         SummaryData->get(Summary::MaxFunctionCount),
         SummaryData->get(Summary::TotalNumBlocks),
         SummaryData->get(Summary::TotalNumFunctions));
     return Cur + SummarySize;
   } else {
     // For older version of profile data, we need to compute on the fly:
if (Magic != IndexedInstrProf::Magic)
     return error(instrprof_error::bad_magic);
 
   // Read the version.
   uint64_t FormatVersion = endian::byte_swap<uint64_t, little>(Header->Version);
   if (GET_VERSION(FormatVersion) >
       IndexedInstrProf::ProfVersion::CurrentVersion)
     return error(instrprof_error::unsupported_version);
 
-  Cur = readSummary((IndexedInstrProf::ProfVersion)FormatVersion, Cur);
+  Cur = readSummary((IndexedInstrProf::ProfVersion)FormatVersion, Cur,
+                    /* UseCS */ false);
+  if (Header->Version & VARIANT_MASK_CSIR_PROF)
+    Cur = readSummary((IndexedInstrProf::ProfVersion)FormatVersion, Cur,
+                      /* UseCS */ true);
 
   // Read the hash type and start offset.
   IndexedInstrProf::HashT HashType = static_cast<IndexedInstrProf::HashT>(
       endian::byte_swap<uint64_t, little>(Header->HashType));
   if (HashType > IndexedInstrProf::HashT::Last)
     return error(instrprof_error::unsupported_hash_type);
 
   uint64_t HashOffset = endian::byte_swap<uint64_t, little>(Header->HashOffset);

lib/ProfileData/InstrProfWriter.cpp

public:
   using data_type = const InstrProfWriter::ProfilingData *const;
   using data_type_ref = const InstrProfWriter::ProfilingData *const;
 
   using hash_value_type = uint64_t;
   using offset_type = uint64_t;
 
   support::endianness ValueProfDataEndianness = support::little;
   InstrProfSummaryBuilder *SummaryBuilder;
+  InstrProfSummaryBuilder *CSSummaryBuilder;
 
   InstrProfRecordWriterTrait() = default;
 
   static hash_value_type ComputeHash(key_type_ref K) {
     return IndexedInstrProf::ComputeHash(K);
   }
 
   static std::pair<offset_type, offset_type>
public:
   }
 
   void EmitData(raw_ostream &Out, key_type_ref, data_type_ref V, offset_type) {
     using namespace support;
 
     endian::Writer LE(Out, little);
     for (const auto &ProfileData : *V) {
       const InstrProfRecord &ProfRecord = ProfileData.second;
+      if (NamedInstrProfRecord::hasCSFlagInHash(ProfileData.first))
+        CSSummaryBuilder->addRecord(ProfRecord);
+      else
         SummaryBuilder->addRecord(ProfRecord);
 
       LE.write<uint64_t>(ProfileData.first); // Function hash
       LE.write<uint64_t>(ProfRecord.Counts.size());
       for (uint64_t I : ProfRecord.Counts)
         LE.write<uint64_t>(I);
 
       // Write value data
       std::unique_ptr<ValueProfData> VDataPtr =

 
 void InstrProfWriter::writeImpl(ProfOStream &OS) {
   using namespace IndexedInstrProf;
 
   OnDiskChainedHashTableGenerator<InstrProfRecordWriterTrait> Generator;
 
   InstrProfSummaryBuilder ISB(ProfileSummaryBuilder::DefaultCutoffs);
   InfoObj->SummaryBuilder = &ISB;
+  InstrProfSummaryBuilder CSISB(ProfileSummaryBuilder::DefaultCutoffs);
+  InfoObj->CSSummaryBuilder = &CSISB;
 
   // Populate the hash table generator.
   for (const auto &I : FunctionData)
     if (shouldEncodeData(I.getValue()))
       Generator.insert(I.getKey(), &I.getValue());
   // Write the header.
   IndexedInstrProf::Header Header;
   Header.Magic = IndexedInstrProf::Magic;
   Header.Version = IndexedInstrProf::ProfVersion::CurrentVersion;
   if (ProfileKind == PF_IRLevel)
     Header.Version |= VARIANT_MASK_IR_PROF;
+  if (ProfileKind == PF_IRLevelWithCS) {
+    Header.Version |= VARIANT_MASK_IR_PROF;
+    Header.Version |= VARIANT_MASK_CSIR_PROF;
+  }
   Header.Unused = 0;
   Header.HashType = static_cast<uint64_t>(IndexedInstrProf::HashType);
   Header.HashOffset = 0;
   int N = sizeof(IndexedInstrProf::Header) / sizeof(uint64_t);
 
   // Only write out all the fields except 'HashOffset'. We need
   // to remember the offset of that field to allow back patching
   // later.
   for (int I = 0; I < N - 1; I++)
     OS.write(reinterpret_cast<uint64_t *>(&Header)[I]);
 
   // Save the location of Header.HashOffset field in \c OS.
   uint64_t HashTableStartFieldOffset = OS.tell();
   // Reserve the space for HashOffset field.
   OS.write(0);
 
   // Reserve space to write profile summary data.
   uint32_t NumEntries = ProfileSummaryBuilder::DefaultCutoffs.size();
   uint32_t SummarySize = Summary::getSize(Summary::NumKinds, NumEntries);
   // Remember the summary offset.
   uint64_t SummaryOffset = OS.tell();
   for (unsigned I = 0; I < SummarySize / sizeof(uint64_t); I++)
     OS.write(0);
+  uint64_t CSSummaryOffset = 0;
+  uint64_t CSSummarySize = 0;
+  if (ProfileKind == PF_IRLevelWithCS) {
+    CSSummaryOffset = OS.tell();
+    CSSummarySize = SummarySize / sizeof(uint64_t);
+    for (unsigned I = 0; I < CSSummarySize; I++)
+      OS.write(0);
+  }
 
   // Write the hash table.
   uint64_t HashTableStart = Generator.Emit(OS.OS, *InfoObj);
 
   // Allocate space for data to be serialized out.
   std::unique_ptr<IndexedInstrProf::Summary> TheSummary =
       IndexedInstrProf::allocSummary(SummarySize);
   // Compute the Summary and copy the data to the data
   // structure to be serialized out (to disk or buffer).
   std::unique_ptr<ProfileSummary> PS = ISB.getSummary();
   setSummary(TheSummary.get(), *PS);
   InfoObj->SummaryBuilder = nullptr;
 
+  // For Context Sensitive summary.
+  std::unique_ptr<IndexedInstrProf::Summary> TheCSSummary = nullptr;
+  if (ProfileKind == PF_IRLevelWithCS) {
+    TheCSSummary = IndexedInstrProf::allocSummary(SummarySize);
+    std::unique_ptr<ProfileSummary> CSPS = CSISB.getSummary();
+    setSummary(TheCSSummary.get(), *CSPS);
+  }
+  InfoObj->CSSummaryBuilder = nullptr;
+
   // Now do the final patch:
   PatchItem PatchItems[] = {
       // Patch the Header.HashOffset field.
       {HashTableStartFieldOffset, &HashTableStart, 1},
       // Patch the summary data.
       {SummaryOffset, reinterpret_cast<uint64_t *>(TheSummary.get()),
-       (int)(SummarySize / sizeof(uint64_t))}};
+       (int)(SummarySize / sizeof(uint64_t))},
+      {CSSummaryOffset, reinterpret_cast<uint64_t *>(TheCSSummary.get()),
+       (int)CSSummarySize}};
+
   OS.patch(PatchItems, sizeof(PatchItems) / sizeof(*PatchItems));
 }
 
 void InstrProfWriter::write(raw_fd_ostream &OS) {
   // Write the hash table.
   ProfOStream POS(OS);
   writeImpl(POS);
 }
void InstrProfWriter::writeRecordInText(StringRef Name, uint64_t Hash,
   }
 
   OS << "\n";
 }
 
 Error InstrProfWriter::writeText(raw_fd_ostream &OS) {
   if (ProfileKind == PF_IRLevel)
     OS << "# IR level Instrumentation Flag\n:ir\n";
+  else if (ProfileKind == PF_IRLevelWithCS)
+    OS << "# CSIR level Instrumentation Flag\n:csir\n";
   InstrProfSymtab Symtab;
   for (const auto &I : FunctionData)
     if (shouldEncodeData(I.getValue()))
       if (Error E = Symtab.addFuncName(I.getKey()))
         return E;
 
   for (const auto &I : FunctionData)
     if (shouldEncodeData(I.getValue()))
       for (const auto &Func : I.getValue())
         writeRecordInText(I.getKey(), Func.first, Func.second, Symtab, OS);
   return Error::success();
 }

lib/Transforms/IPO/PassManagerBuilder.cpp

PassManagerBuilder::PassManagerBuilder() {
     RerollLoops = RunLoopRerolling;
     NewGVN = RunNewGVN;
     DisableGVNLoadPRE = false;
     VerifyInput = false;
     VerifyOutput = false;
     MergeFunctions = false;
     PrepareForLTO = false;
     EnablePGOInstrGen = false;
+    EnablePGOCSInstrGen = false;
+    EnablePGOCSInstrUse = false;
     PGOInstrGen = "";
     PGOInstrUse = "";
     PGOSampleUse = "";
     PrepareForThinLTO = EnablePrepareForThinLTO;
     PerformThinLTO = EnablePerformThinLTO;
     DivergentTarget = false;
 }
 
void PassManagerBuilder::populateFunctionPassManager(
 
   FPM.add(createCFGSimplificationPass());
   FPM.add(createSROAPass());
   FPM.add(createEarlyCSEPass());
   FPM.add(createLowerExpectIntrinsicPass());
 }
 
 // Do PGO instrumentation generation or use pass as the option specified.
-void PassManagerBuilder::addPGOInstrPasses(legacy::PassManagerBase &MPM) {
-  if (!EnablePGOInstrGen && PGOInstrUse.empty() && PGOSampleUse.empty())
+void PassManagerBuilder::addPGOInstrPasses(legacy::PassManagerBase &MPM,
+                                           bool IsCS = false) {
+  if (IsCS) {
+    if (!EnablePGOCSInstrGen && !EnablePGOCSInstrUse)
       return;
+  } else if (!EnablePGOInstrGen && PGOInstrUse.empty() && PGOSampleUse.empty())
+    return;
+
   // Perform the preinline and cleanup passes for O1 and above.
   // And avoid doing them if optimizing for size.
   if (OptLevel > 0 && SizeLevel == 0 && !DisablePreInliner &&
-      PGOSampleUse.empty()) {
+      PGOSampleUse.empty() && !IsCS) {
     // Create preinline pass. We construct an InlineParams object and specify
     // the threshold here to avoid the command line options of the regular
     // inliner to influence pre-inlining. The only fields of InlineParams we
     // care about are DefaultThreshold and HintThreshold.
     InlineParams IP;
     IP.DefaultThreshold = PreInlineThreshold;
     // FIXME: The hint threshold has the same value used by the regular inliner.
     // This should probably be lowered after performance testing.
     IP.HintThreshold = 325;
 
     MPM.add(createFunctionInliningPass(IP));
     MPM.add(createSROAPass());
     MPM.add(createEarlyCSEPass());             // Catch trivial redundancies
     MPM.add(createCFGSimplificationPass());    // Merge & remove BBs
     MPM.add(createInstructionCombiningPass()); // Combine silly seq's
     addExtensionsToPM(EP_Peephole, MPM);
   }
-  if (EnablePGOInstrGen) {
-    MPM.add(createPGOInstrumentationGenLegacyPass());
+  if ((EnablePGOInstrGen && !IsCS) || (EnablePGOCSInstrGen && IsCS)) {
+    MPM.add(createPGOInstrumentationGenLegacyPass(IsCS));
     // Add the profile lowering pass.
     InstrProfOptions Options;
     if (!PGOInstrGen.empty())
       Options.InstrProfileOutput = PGOInstrGen;
     Options.DoCounterPromotion = true;
+    Options.UseBFIInPromotion = IsCS;
     MPM.add(createLoopRotatePass());
-    MPM.add(createInstrProfilingLegacyPass(Options));
+    MPM.add(createInstrProfilingLegacyPass(Options, IsCS));
   }
   if (!PGOInstrUse.empty())
-    MPM.add(createPGOInstrumentationUseLegacyPass(PGOInstrUse));
+    MPM.add(createPGOInstrumentationUseLegacyPass(PGOInstrUse, IsCS));
   // Indirect call promotion that promotes intra-module targets only.
   // For ThinLTO this is done earlier due to interactions with globalopt
   // for imported functions. We don't run this at -O0.
-  if (OptLevel > 0)
+  if (OptLevel > 0 && !IsCS)
     MPM.add(
         createPGOIndirectCallPromotionLegacyPass(false, !PGOSampleUse.empty()));
 }
 void PassManagerBuilder::addFunctionSimplificationPasses(
     legacy::PassManagerBase &MPM) {
   // Start of function pass.
   // Break up aggregate allocas, using SSAUpdater.
   MPM.add(createSROAPass());
void PassManagerBuilder::populateModulePassManager(
   // For SamplePGO in ThinLTO compile phase, we do not want to do indirect
   // call promotion as it will change the CFG too much to make the 2nd
   // profile annotation in backend more difficult.
   // PGO instrumentation is added during the compile phase for ThinLTO, do
   // not run it a second time
   if (!PerformThinLTO && !PrepareForThinLTOUsingPGOSampleProfile)
     addPGOInstrPasses(MPM);
 
+  // Create profile COMDAT variables. Lld linker wants to see all variables
+  // before the LTO/ThinLTO link since it needs to resolve symbols/comdats.
+  if (!PerformThinLTO && EnablePGOCSInstrGen)
+    MPM.add(createPGOInstrumentationGenCreateVarLegacyPass(PGOInstrGen));
+
   // We add a module alias analysis pass here. In part due to bugs in the
   // analysis infrastructure this "works" in that the analysis stays alive
   // for the entire SCC pass run below.
   MPM.add(createGlobalsAAWrapperPass());
 
   // Start of CallGraph SCC passes.
   MPM.add(createPruneEHPass()); // Remove dead EH info
   bool RunInliner = false;
void PassManagerBuilder::populateModulePassManager(
   // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
   // pass manager that we are specifically trying to avoid. To prevent this
   // we must insert a no-op module pass to reset the pass manager.
   MPM.add(createBarrierNoopPass());
 
   if (RunPartialInlining)
     MPM.add(createPartialInliningPass());
 
+  // CSFDO instrumentation and use pass. Don't invoke this for Prepare pass
+  // for LTO and ThinLTO -- The actual pass will be called after all inlines
+  // are performed.
+  if (!(PrepareForLTO || PrepareForThinLTO))
+    addPGOInstrPasses(MPM, /* IsCS */ true);
+
   if (OptLevel > 1 && !PrepareForLTO && !PrepareForThinLTO)
     // Remove avail extern fns and globals definitions if we aren't
     // compiling an object file for later LTO. For LTO we want to preserve
     // these so they are eligible for inlining at link-time. Note if they
     // are unreferenced they will be removed by GlobalDCE later, so
     // this only impacts referenced available externally globals.
     // Eventually they will be suppressed during codegen, but eliminating
     // here enables more opportunity for GlobalDCE as it may make
void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
   bool RunInliner = Inliner;
   if (RunInliner) {
     PM.add(Inliner);
     Inliner = nullptr;
   }
 
   PM.add(createPruneEHPass());   // Remove dead EH info.
 
+  // CSFDO instrumentation and use pass.
+  addPGOInstrPasses(PM, /* IsCS */ true);
+
   // Optimize globals again if we ran the inliner.
   if (RunInliner)
     PM.add(createGlobalOptimizerPass());
   PM.add(createGlobalDCEPass()); // Remove dead functions.
 
   // If we didn't decide to inline a function, check to see if we can
   // transform it to pass arguments by value instead of by reference.
   PM.add(createArgumentPromotionPass());

lib/Transforms/IPO/SampleProfile.cpp

 
 bool SampleProfileLoader::runOnModule(Module &M, ModuleAnalysisManager *AM,
                                       ProfileSummaryInfo *_PSI) {
   FunctionSamples::GUIDToFuncNameMapper Mapper(M);
   if (!ProfileIsValid)
     return false;
 
   PSI = _PSI;
-  if (M.getProfileSummary() == nullptr)
-    M.setProfileSummary(Reader->getSummary().getMD(M.getContext()));
+  if (M.getProfileSummary(ProfileSummary::PSK_Sample) == nullptr)
+    M.setProfileSummary(Reader->getSummary().getMD(M.getContext()),
+                        ProfileSummary::PSK_Sample);
 
   // Compute the total number of samples collected in this profile.
   for (const auto &I : Reader->getProfiles())
     TotalCollectedSamples += I.second.getTotalSamples();
 
   // Populate the symbol map.
   for (const auto &N_F : M.getValueSymbolTable()) {
     StringRef OrigName = N_F.getKey();

lib/Transforms/Instrumentation/InstrProfiling.cpp

 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Instrumentation/InstrProfiling.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Analysis/BlockFrequencyInfo.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Dominators.h"

 
 class InstrProfilingLegacyPass : public ModulePass {
   InstrProfiling InstrProf;
 
 public:
   static char ID;
 
   InstrProfilingLegacyPass() : ModulePass(ID) {}
-  InstrProfilingLegacyPass(const InstrProfOptions &Options)
-      : ModulePass(ID), InstrProf(Options) {}
+  InstrProfilingLegacyPass(const InstrProfOptions &Options, bool IsCS)
+      : ModulePass(ID), InstrProf(Options, IsCS) {}
 
   StringRef getPassName() const override {
     return "Frontend instrumentation-based coverage lowering";
   }
 
   bool runOnModule(Module &M) override {
     return InstrProf.run(M, getAnalysis<TargetLibraryInfoWrapperPass>().getTLI());
   }

 
 /// A helper class to do register promotion for all profile counter
 /// updates in a loop.
 ///
 class PGOCounterPromoter {
 public:
   PGOCounterPromoter(
       DenseMap<Loop *, SmallVector<LoadStorePair, 8>> &LoopToCands,
-      Loop &CurLoop, LoopInfo &LI)
+      Loop &CurLoop, LoopInfo &LI, BlockFrequencyInfo *BFI)
       : LoopToCandidates(LoopToCands), ExitBlocks(), InsertPts(), L(CurLoop),
-        LI(LI) {
+        LI(LI), BFI(BFI) {
 
     SmallVector<BasicBlock *, 8> LoopExitBlocks;
     SmallPtrSet<BasicBlock *, 8> BlockSet;
     L.getExitBlocks(LoopExitBlocks);
 
     for (BasicBlock *ExitBlock : LoopExitBlocks) {
       if (BlockSet.insert(ExitBlock).second) {
         ExitBlocks.push_back(ExitBlock);
bool run(int64_t *NumPromoted) {
 
     unsigned Promoted = 0;
     for (auto &Cand : LoopToCandidates[&L]) {
 
       SmallVector<PHINode *, 4> NewPHIs;
       SSAUpdater SSA(&NewPHIs);
       Value *InitVal = ConstantInt::get(Cand.first->getType(), 0);
 
+      // If BFI is set, we will use it to guide the promotions.
+      if (BFI) {
+        auto *BB = Cand.first->getParent();
+        auto InstrCount = BFI->getBlockProfileCount(BB);
+        if (!InstrCount)
+          continue;
+        auto PreheaderCount = BFI->getBlockProfileCount(L.getLoopPreheader());
+        // If the average loop trip count is not greater than 1.5, we skip
+        // promotion.
+        if (PreheaderCount &&
+            (PreheaderCount.getValue() * 3) >= (InstrCount.getValue() * 2))
+          continue;
+      }
+
       PGOCounterPromoterHelper Promoter(Cand.first, Cand.second, SSA, InitVal,
                                         L.getLoopPreheader(), ExitBlocks,
                                         InsertPts, LoopToCandidates, LI);
       Promoter.run(SmallVector<Instruction *, 2>({Cand.first, Cand.second}));
       Promoted++;
       if (Promoted >= MaxProm)
         break;
 
if (!LP->hasDedicatedExits())
       return 0;
 
     BasicBlock *PH = LP->getLoopPreheader();
     if (!PH)
       return 0;
 
     SmallVector<BasicBlock *, 8> ExitingBlocks;
     LP->getExitingBlocks(ExitingBlocks);
+
+    // If BFI is set, we do more aggressive promotions based on BFI.
+    if (BFI)
+      return (unsigned)-1;
+
     // Not considierered speculative.
     if (ExitingBlocks.size() == 1)
       return MaxNumOfPromotionsPerLoop;
 
     if (ExitingBlocks.size() > SpeculativeCounterPromotionMaxExiting)
       return 0;
 
     // Whether the target block is in a loop does not matter:
unsigned getMaxNumOfPromotionsInLoop(Loop *LP) {
     return MaxProm;
   }
 
   DenseMap<Loop *, SmallVector<LoadStorePair, 8>> &LoopToCandidates;
   SmallVector<BasicBlock *, 8> ExitBlocks;
   SmallVector<Instruction *, 8> InsertPts;
   Loop &L;
   LoopInfo &LI;
+  BlockFrequencyInfo *BFI;
 };
 
 } // end anonymous namespace
 
 PreservedAnalyses InstrProfiling::run(Module &M, ModuleAnalysisManager &AM) {
   auto &TLI = AM.getResult<TargetLibraryAnalysis>(M);
   if (!run(M, TLI))
     return PreservedAnalyses::all();
 
   return PreservedAnalyses::none();
 }
 
 char InstrProfilingLegacyPass::ID = 0;
 INITIALIZE_PASS_BEGIN(
     InstrProfilingLegacyPass, "instrprof",
     "Frontend instrumentation-based coverage lowering.", false, false)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 INITIALIZE_PASS_END(
     InstrProfilingLegacyPass, "instrprof",
     "Frontend instrumentation-based coverage lowering.", false, false)
 
 ModulePass *
-llvm::createInstrProfilingLegacyPass(const InstrProfOptions &Options) {
-  return new InstrProfilingLegacyPass(Options);
+llvm::createInstrProfilingLegacyPass(const InstrProfOptions &Options,
+                                     bool IsCS) {
+  return new InstrProfilingLegacyPass(Options, IsCS);
 }
 
 static InstrProfIncrementInst *castToIncrementInst(Instruction *Instr) {
   InstrProfIncrementInst *Inc = dyn_cast<InstrProfIncrementInstStep>(Instr);
   if (Inc)
     return Inc;
   return dyn_cast<InstrProfIncrementInst>(Instr);
 }

 void InstrProfiling::promoteCounterLoadStores(Function *F) {
   if (!isCounterPromotionEnabled())
     return;
 
   DominatorTree DT(*F);
   LoopInfo LI(DT);
   DenseMap<Loop *, SmallVector<LoadStorePair, 8>> LoopPromotionCandidates;
 
+  std::unique_ptr<BlockFrequencyInfo> BFI;
+  if (Options.UseBFIInPromotion) {
+    std::unique_ptr<BranchProbabilityInfo> BPI;
+    BPI.reset(new BranchProbabilityInfo(*F, LI, TLI));
+    BFI.reset(new BlockFrequencyInfo(*F, *BPI, LI));
+  }
+
   for (const auto &LoadStore : PromotionCandidates) {
     auto *CounterLoad = LoadStore.first;
     auto *CounterStore = LoadStore.second;
     BasicBlock *BB = CounterLoad->getParent();
     Loop *ParentLoop = LI.getLoopFor(BB);
     if (!ParentLoop)
       continue;
     LoopPromotionCandidates[ParentLoop].emplace_back(CounterLoad, CounterStore);
   }
 
   SmallVector<Loop *, 4> Loops = LI.getLoopsInPreorder();
 
   // Do a post-order traversal of the loops so that counter updates can be
   // iteratively hoisted outside the loop nest.
   for (auto *Loop : llvm::reverse(Loops)) {
-    PGOCounterPromoter Promoter(LoopPromotionCandidates, *Loop, LI);
+    PGOCounterPromoter Promoter(LoopPromotionCandidates, *Loop, LI, BFI.get());
     Promoter.run(&TotalCountersPromoted);
   }
 }
 
 /// Check if the module contains uses of any profiling intrinsics.
 static bool containsProfilingIntrinsics(Module &M) {
   if (auto *F = M.getFunction(
           Intrinsic::getName(llvm::Intrinsic::instrprof_increment)))
StringRef ComdatPrefix = (Triple(M.getTargetTriple()).isOSBinFormatCOFF()
                                 : getInstrProfComdatPrefix());
   return M.getOrInsertComdat(StringRef(getVarName(Inc, ComdatPrefix)));
 }
 
 static bool needsRuntimeRegistrationOfSectionRange(const Module &M) {
   // Don't do this for Darwin.  compiler-rt uses linker magic.
   if (Triple(M.getTargetTriple()).isOSDarwin())
     return false;
-
   // Use linker script magic to get data/cnts/name start/end.
   if (Triple(M.getTargetTriple()).isOSLinux() ||
       Triple(M.getTargetTriple()).isOSFreeBSD() ||
       Triple(M.getTargetTriple()).isOSNetBSD() ||
       Triple(M.getTargetTriple()).isOSFuchsia() ||
       Triple(M.getTargetTriple()).isPS4CPU())
     return false;
 

 }
 
 void InstrProfiling::emitUses() {
   if (!UsedVars.empty())
     appendToUsed(*M, UsedVars);
 }
 
 void InstrProfiling::emitInitialization() {
+  // Don't create ProfileName variable for context-sensitive instrumetation
+  // lowering: This lowering is after LTO/ThinLTO linking. Pass
+  // PGOInstrumentationGenCreateVar should have already create the
+  // variable before LTO/ThinLTO linking.
+  if (!IsCS) {
     StringRef InstrProfileOutput = Options.InstrProfileOutput;
-
-  if (!InstrProfileOutput.empty()) {
-    // Create variable for profile name.
-    Constant *ProfileNameConst =
-        ConstantDataArray::getString(M->getContext(), InstrProfileOutput, true);
-    GlobalVariable *ProfileNameVar = new GlobalVariable(
-        *M, ProfileNameConst->getType(), true, GlobalValue::WeakAnyLinkage,
-        ProfileNameConst, INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_NAME_VAR));
-    if (TT.supportsCOMDAT()) {
-      ProfileNameVar->setLinkage(GlobalValue::ExternalLinkage);
-      ProfileNameVar->setComdat(M->getOrInsertComdat(
-          StringRef(INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_NAME_VAR))));
-    }
+    createProfileNameVar(*M, InstrProfileOutput);
   }
 
   Constant *RegisterF = M->getFunction(getInstrProfRegFuncsName());
   if (!RegisterF)
     return;
 
   // Create the initialization function.
   auto *VoidTy = Type::getVoidTy(M->getContext());

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Analysis/BlockFrequencyInfo.h"
 #include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/IndirectCallVisitor.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
+#include "llvm/Analysis/ProfileSummaryInfo.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Comdat.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DiagnosticInfo.h"

 STATISTIC(NumOfPGOMemIntrinsics, "Number of mem intrinsics instrumented.");
 STATISTIC(NumOfPGOEdge, "Number of edges.");
 STATISTIC(NumOfPGOBB, "Number of basic-blocks.");
 STATISTIC(NumOfPGOSplit, "Number of critical edge splits.");
 STATISTIC(NumOfPGOFunc, "Number of functions having valid profile counts.");
 STATISTIC(NumOfPGOMismatch, "Number of functions having mismatch profile.");
 STATISTIC(NumOfPGOMissing, "Number of functions without profile.");
 STATISTIC(NumOfPGOICall, "Number of indirect call value instrumentations.");
+STATISTIC(NumOfCSPGOInstrument, "Number of edges instrumented in CSPGO.");
+STATISTIC(NumOfCSPGOSelectInsts,
+          "Number of select instruction instrumented in CSPGO.");
+STATISTIC(NumOfCSPGOMemIntrinsics,
+          "Number of mem intrinsics instrumented in CSPGO.");
+STATISTIC(NumOfCSPGOEdge, "Number of edges in CSPGO.");
+STATISTIC(NumOfCSPGOBB, "Number of basic-blocks in CSPGO.");
+STATISTIC(NumOfCSPGOSplit, "Number of critical edge splits in CSPGO.");
+STATISTIC(NumOfCSPGOFunc,
+          "Number of functions having valid profile counts in CSPGO.");
+STATISTIC(NumOfCSPGOMismatch,
+          "Number of functions having mismatch profile in CSPGO.");
+STATISTIC(NumOfCSPGOMissing, "Number of functions without profile in CSPGO.");
 
 // Command line option to specify the file to read profile from. This is
 // mainly used for testing.
 static cl::opt<std::string>
     PGOTestProfileFile("pgo-test-profile-file", cl::init(""), cl::Hidden,
                        cl::value_desc("filename"),
                        cl::desc("Specify the path of profile data file. This is"
                                 "mainly for test purpose."));
struct MemIntrinsicVisitor : public InstVisitor<MemIntrinsicVisitor> {
 
   unsigned getNumOfMemIntrinsics() const { return NMemIs; }
 };
 
 class PGOInstrumentationGenLegacyPass : public ModulePass {
 public:
   static char ID;
 
-  PGOInstrumentationGenLegacyPass() : ModulePass(ID) {
+  PGOInstrumentationGenLegacyPass(bool IsCS = false)
+      : ModulePass(ID), IsCS(IsCS) {
     initializePGOInstrumentationGenLegacyPassPass(
         *PassRegistry::getPassRegistry());
   }
 
   StringRef getPassName() const override { return "PGOInstrumentationGenPass"; }
 
 private:
+  // Is this is context-sensitive instrumentation.
+  bool IsCS;
   bool runOnModule(Module &M) override;
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<BlockFrequencyInfoWrapperPass>();
   }
 };
 
 class PGOInstrumentationUseLegacyPass : public ModulePass {
 public:
   static char ID;
 
   // Provide the profile filename as the parameter.
-  PGOInstrumentationUseLegacyPass(std::string Filename = "")
-      : ModulePass(ID), ProfileFileName(std::move(Filename)) {
+  PGOInstrumentationUseLegacyPass(std::string Filename = "", bool IsCS = false)
+      : ModulePass(ID), ProfileFileName(std::move(Filename)), IsCS(IsCS) {
     if (!PGOTestProfileFile.empty())
       ProfileFileName = PGOTestProfileFile;
     initializePGOInstrumentationUseLegacyPassPass(
         *PassRegistry::getPassRegistry());
   }
 
   StringRef getPassName() const override { return "PGOInstrumentationUsePass"; }
 
 private:
   std::string ProfileFileName;
+  // Is this is context-sensitive instrumentation use.
+  bool IsCS;
 
   bool runOnModule(Module &M) override;
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<ProfileSummaryInfoWrapperPass>();
     AU.addRequired<BlockFrequencyInfoWrapperPass>();
   }
 };
 
+class PGOInstrumentationGenCreateVarLegacyPass : public ModulePass {
+public:
+  static char ID;
+  StringRef getPassName() const override {
+    return "PGOInstrumentationGenCreateVarPass";
+  }
+  PGOInstrumentationGenCreateVarLegacyPass(std::string CSInstrName = "")
+      : ModulePass(ID), InstrProfileOutput(CSInstrName) {
+    initializePGOInstrumentationGenCreateVarLegacyPassPass(
+        *PassRegistry::getPassRegistry());
+  }
+
+private:
+  bool runOnModule(Module &M) override {
+    createProfileNameVar(M, InstrProfileOutput);
+    createIRLevelProfileFlagVar(M, true);
+    return false;
+  }
+  std::string InstrProfileOutput;
+};
+
 } // end anonymous namespace
 
 char PGOInstrumentationGenLegacyPass::ID = 0;
 
 INITIALIZE_PASS_BEGIN(PGOInstrumentationGenLegacyPass, "pgo-instr-gen",
                       "PGO instrumentation.", false, false)
 INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
 INITIALIZE_PASS_END(PGOInstrumentationGenLegacyPass, "pgo-instr-gen",
                     "PGO instrumentation.", false, false)
 
-ModulePass *llvm::createPGOInstrumentationGenLegacyPass() {
-  return new PGOInstrumentationGenLegacyPass();
+ModulePass *llvm::createPGOInstrumentationGenLegacyPass(bool IsCS) {
+  return new PGOInstrumentationGenLegacyPass(IsCS);
 }
 
 char PGOInstrumentationUseLegacyPass::ID = 0;
 
 INITIALIZE_PASS_BEGIN(PGOInstrumentationUseLegacyPass, "pgo-instr-use",
                       "Read PGO instrumentation profile.", false, false)
 INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
 INITIALIZE_PASS_END(PGOInstrumentationUseLegacyPass, "pgo-instr-use",
                     "Read PGO instrumentation profile.", false, false)
 
-ModulePass *llvm::createPGOInstrumentationUseLegacyPass(StringRef Filename) {
-  return new PGOInstrumentationUseLegacyPass(Filename.str());
+ModulePass *llvm::createPGOInstrumentationUseLegacyPass(StringRef Filename,
+                                                        bool IsCS) {
+  return new PGOInstrumentationUseLegacyPass(Filename.str(), IsCS);
+}
+
+#if 1
+char PGOInstrumentationGenCreateVarLegacyPass::ID = 0;
+
+INITIALIZE_PASS(PGOInstrumentationGenCreateVarLegacyPass,
+                "pgo-instr-gen-create-var",
+                "Create PGO instrumentation version variable for CSPGO.", false,
+                false)
+
+ModulePass *
+llvm::createPGOInstrumentationGenCreateVarLegacyPass(StringRef CSInstrName) {
+  return new PGOInstrumentationGenCreateVarLegacyPass(CSInstrName);
 }
+#endif
 
 namespace {
 
 /// An MST based instrumentation for PGO
 ///
 /// Implements a Minimum Spanning Tree (MST) based instrumentation for PGO
 /// in the function level.
 struct PGOEdge {
const std::string infoString() const {
     return (Twine("Index=") + Twine(Index)).str();
   }
 };
 
 // This class implements the CFG edges. Note the CFG can be a multi-graph.
 template <class Edge, class BBInfo> class FuncPGOInstrumentation {
 private:
   Function &F;
 
+  // Is this is context-sensitive instrumentation.
+  bool IsCS;
+
   // A map that stores the Comdat group in function F.
   std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers;
 
   void computeCFGHash();
   void renameComdatFunction();
 
 public:
   std::vector<std::vector<Instruction *>> ValueSites;
void dumpInfo(std::string Str = "") const {
     MST.dumpEdges(dbgs(), Twine("Dump Function ") + FuncName + " Hash: " +
                               Twine(FunctionHash) + "\t" + Str);
   }
 
   FuncPGOInstrumentation(
       Function &Func,
       std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers,
       bool CreateGlobalVar = false, BranchProbabilityInfo *BPI = nullptr,
-      BlockFrequencyInfo *BFI = nullptr)
-      : F(Func), ComdatMembers(ComdatMembers), ValueSites(IPVK_Last + 1),
-        SIVisitor(Func), MIVisitor(Func), MST(F, BPI, BFI) {
+      BlockFrequencyInfo *BFI = nullptr, bool IsCS = false)
+      : F(Func), IsCS(IsCS), ComdatMembers(ComdatMembers),
+        ValueSites(IPVK_Last + 1), SIVisitor(Func), MIVisitor(Func),
+        MST(F, BPI, BFI) {
     // This should be done before CFG hash computation.
     SIVisitor.countSelects(Func);
     MIVisitor.countMemIntrinsics(Func);
+    if (!IsCS) {
       NumOfPGOSelectInsts += SIVisitor.getNumOfSelectInsts();
       NumOfPGOMemIntrinsics += MIVisitor.getNumOfMemIntrinsics();
+      NumOfPGOBB += MST.BBInfos.size();
       ValueSites[IPVK_IndirectCallTarget] = findIndirectCalls(Func);
+    } else {
+      NumOfCSPGOSelectInsts += SIVisitor.getNumOfSelectInsts();
+      NumOfCSPGOMemIntrinsics += MIVisitor.getNumOfMemIntrinsics();
+      NumOfCSPGOBB += MST.BBInfos.size();
+    }
     ValueSites[IPVK_MemOPSize] = MIVisitor.findMemIntrinsics(Func);
 
     FuncName = getPGOFuncName(F);
     computeCFGHash();
     if (!ComdatMembers.empty())
       renameComdatFunction();
     LLVM_DEBUG(dumpInfo("after CFGMST"));
 
-    NumOfPGOBB += MST.BBInfos.size();
     for (auto &E : MST.AllEdges) {
       if (E->Removed)
         continue;
-      NumOfPGOEdge++;
+      IsCS ? NumOfCSPGOEdge++ : NumOfPGOEdge++;
       if (!E->InMST)
-        NumOfPGOInstrument++;
+        IsCS ? NumOfCSPGOInstrument++ : NumOfPGOInstrument++;
     }
 
     if (CreateGlobalVar)
       FuncNameVar = createPGOFuncNameVar(F, FuncName);
   }
 
   // Return the number of profile counters needed for the function.
   unsigned getNumCounters() {
for (unsigned I = 0, E = TI->getNumSuccessors(); I != E; ++I) {
       if (BI == nullptr)
         continue;
       uint32_t Index = BI->Index;
       for (int J = 0; J < 4; J++)
         Indexes.push_back((char)(Index >> (J * 8)));
     }
   }
   JC.update(Indexes);
+
+  // Hash format for context sensitive profile. Reserve 4 bits for other
+  // information.
   FunctionHash = (uint64_t)SIVisitor.getNumOfSelectInsts() << 56 |
                  (uint64_t)ValueSites[IPVK_IndirectCallTarget].size() << 48 |
                  (uint64_t)MST.AllEdges.size() << 32 | JC.getCRC();
+  // Reserve bit 60-63 for other information purpose.
+  FunctionHash &= 0x0FFFFFFFFFFFFFFF;
+  if (IsCS)
+    NamedInstrProfRecord::setCSFlagInHash(FunctionHash);
   LLVM_DEBUG(dbgs() << "Function Hash Computation for " << F.getName() << ":\n"
                     << " CRC = " << JC.getCRC()
                     << ", Selects = " << SIVisitor.getNumOfSelectInsts()
                     << ", Edges = " << MST.AllEdges.size() << ", ICSites = "
                     << ValueSites[IPVK_IndirectCallTarget].size()
                     << ", Hash = " << FunctionHash << "\n";);
 }
 
 // Check if we can safely rename this Comdat function.
 static bool canRenameComdat(
     Function &F,
     std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers) {
   if (!DoComdatRenaming || !canRenameComdatFunc(F, true))
     return false;
BasicBlock *FuncPGOInstrumentation<Edge, BBInfo>::getInstrBB(Edge *E) {
   Instruction *TI = SrcBB->getTerminator();
   if (TI->getNumSuccessors() <= 1)
     return SrcBB;
   if (!E->IsCritical)
     return DestBB;
 
   // For a critical edge, we have to split. Instrument the newly
   // created BB.
-  NumOfPGOSplit++;
+  IsCS ? NumOfCSPGOSplit++ : NumOfPGOSplit++;
   LLVM_DEBUG(dbgs() << "Split critical edge: " << getBBInfo(SrcBB).Index
                     << " --> " << getBBInfo(DestBB).Index << "\n");
   unsigned SuccNum = GetSuccessorNumber(SrcBB, DestBB);
   BasicBlock *InstrBB = SplitCriticalEdge(TI, SuccNum);
   assert(InstrBB && "Critical edge is not split");
 
   E->Removed = true;
   return InstrBB;
 }
 
 // Visit all edge and instrument the edges not in MST, and do value profiling.
 // Critical edges will be split.
 static void instrumentOneFunc(
     Function &F, Module *M, BranchProbabilityInfo *BPI, BlockFrequencyInfo *BFI,
-    std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers) {
+    std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers,
+    bool IsCS) {
   // Split indirectbr critical edges here before computing the MST rather than
   // later in getInstrBB() to avoid invalidating it.
   SplitIndirectBrCriticalEdges(F, BPI, BFI);
+
   FuncPGOInstrumentation<PGOEdge, BBInfo> FuncInfo(F, ComdatMembers, true, BPI,
-                                                   BFI);
+                                                   BFI, IsCS);
   unsigned NumCounters = FuncInfo.getNumCounters();
 
   uint32_t I = 0;
   Type *I8PtrTy = Type::getInt8PtrTy(M->getContext());
   for (auto &E : FuncInfo.MST.AllEdges) {
     BasicBlock *InstrBB = FuncInfo.getInstrBB(E.get());
     if (!InstrBB)
       continue;

 
 namespace {
 
 class PGOUseFunc {
 public:
   PGOUseFunc(Function &Func, Module *Modu,
              std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers,
              BranchProbabilityInfo *BPI = nullptr,
-             BlockFrequencyInfo *BFIin = nullptr)
+             BlockFrequencyInfo *BFIin = nullptr, bool IsCS = false)
       : F(Func), M(Modu), BFI(BFIin),
-        FuncInfo(Func, ComdatMembers, false, BPI, BFIin),
-        FreqAttr(FFA_Normal) {}
+        FuncInfo(Func, ComdatMembers, false, BPI, BFIin, IsCS),
+        FreqAttr(FFA_Normal), IsCS(IsCS) {}
 
   // Read counts for the instrumented BB from profile.
   bool readCounters(IndexedInstrProfReader *PGOReader, bool &AllZeros);
 
   // Populate the counts for all BBs.
   void populateCounters();
 
   // Set the branch weights based on the count values.
private:
   uint32_t ProfileCountSize = 0;
 
   // ProfileRecord for this function.
   InstrProfRecord ProfileRecord;
 
   // Function hotness info derived from profile.
   FuncFreqAttr FreqAttr;
 
+  // Is to use the context sensitive profile.
+  bool IsCS;
+
   // Find the Instrumented BB and set the value.
   void setInstrumentedCounts(const std::vector<uint64_t> &CountFromProfile);
 
   // Set the edge counter value for the unknown edge -- there should be only
   // one unknown edge.
   void setEdgeCount(DirectEdges &Edges, uint64_t Value);
 
   // Return FuncName string;

 bool PGOUseFunc::readCounters(IndexedInstrProfReader *PGOReader, bool &AllZeros) {
   auto &Ctx = M->getContext();
   Expected<InstrProfRecord> Result =
       PGOReader->getInstrProfRecord(FuncInfo.FuncName, FuncInfo.FunctionHash);
   if (Error E = Result.takeError()) {
     handleAllErrors(std::move(E), [&](const InstrProfError &IPE) {
       auto Err = IPE.get();
       bool SkipWarning = false;
+      LLVM_DEBUG(dbgs() << "Error in reading profile for Func "
+                        << FuncInfo.FuncName << ": ");
       if (Err == instrprof_error::unknown_function) {
-        NumOfPGOMissing++;
+        IsCS ? NumOfCSPGOMissing++ : NumOfPGOMissing++;
         SkipWarning = !PGOWarnMissing;
+        LLVM_DEBUG(dbgs() << "unknown function");
       } else if (Err == instrprof_error::hash_mismatch ||
                  Err == instrprof_error::malformed) {
-        NumOfPGOMismatch++;
+        IsCS ? NumOfCSPGOMismatch++ : NumOfPGOMismatch++;
         SkipWarning =
             NoPGOWarnMismatch ||
             (NoPGOWarnMismatchComdat &&
              (F.hasComdat() ||
               F.getLinkage() == GlobalValue::AvailableExternallyLinkage));
+        LLVM_DEBUG(dbgs() << "hash mismatch (skip=" << SkipWarning << ")");
       }
 
+      LLVM_DEBUG(dbgs() << " IsCS=" << IsCS << "\n");
       if (SkipWarning)
         return;
 
-      std::string Msg = IPE.message() + std::string(" ") + F.getName().str();
+      std::string Msg = IPE.message() + std::string(" ") + F.getName().str() +
+                        std::string(" Hash = ") +
+                        std::to_string(FuncInfo.FunctionHash);
+
       Ctx.diagnose(
           DiagnosticInfoPGOProfile(M->getName().data(), Msg, DS_Warning));
     });
     return false;
   }
   ProfileRecord = std::move(Result.get());
   std::vector<uint64_t> &CountFromProfile = ProfileRecord.Counts;
 
-  NumOfPGOFunc++;
+  IsCS ? NumOfCSPGOFunc++ : NumOfPGOFunc++;
   LLVM_DEBUG(dbgs() << CountFromProfile.size() << " counts\n");
   uint64_t ValueSum = 0;
   for (unsigned I = 0, S = CountFromProfile.size(); I < S; I++) {
     LLVM_DEBUG(dbgs() << "  " << I << ": " << CountFromProfile[I] << "\n");
     ValueSum += CountFromProfile[I];
   }
   AllZeros = (ValueSum == 0);
 
   LLVM_DEBUG(dbgs() << "SUM =  " << ValueSum << "\n");
 
   getBBInfo(nullptr).UnknownCountOutEdge = 2;
   getBBInfo(nullptr).UnknownCountInEdge = 2;
 
   setInstrumentedCounts(CountFromProfile);
-  ProgramMaxCount = PGOReader->getMaximumFunctionCount();
+  ProgramMaxCount = PGOReader->getMaximumFunctionCount(IsCS);
   return true;
 }
 
 // Populate the counters from instrumented BBs to all BBs.
 // In the end of this operation, all BBs should have a valid count value.
 void PGOUseFunc::populateCounters() {
   // First set up Count variable for all BBs.
   for (auto &E : FuncInfo.MST.AllEdges) {
#endif
   assert(CountPosition == ProfileCountSize);
 
   LLVM_DEBUG(FuncInfo.dumpInfo("after reading profile."));
 }
 
 // Assign the scaled count values to the BB with multiple out edges.
 void PGOUseFunc::setBranchWeights() {
   // Generate MD_prof metadata for every branch instruction.
-  LLVM_DEBUG(dbgs() << "\nSetting branch weights.\n");
+  LLVM_DEBUG(dbgs() << "\nSetting branch weights for func " << F.getName()
+                    << " IsCS=" << IsCS << "\n");
   for (auto &BB : F) {
     Instruction *TI = BB.getTerminator();
     if (TI->getNumSuccessors() < 2)
       continue;
     if (!(isa<BranchInst>(TI) || isa<SwitchInst>(TI) ||
           isa<IndirectBrInst>(TI)))
       continue;
+
     if (getBBInfo(&BB).CountValue == 0)
       continue;
 
     // We have a non-zero Branch BB.
     const UseBBInfo &BBCountInfo = getBBInfo(&BB);
     unsigned Size = BBCountInfo.OutEdges.size();
     SmallVector<uint64_t, 2> EdgeCounts(Size, 0);
     uint64_t MaxCount = 0;
for (auto &I : ValueSites) {
     annotateValueSite(*M, *I, ProfileRecord,
                       static_cast<InstrProfValueKind>(Kind), ValueSiteIndex,
                       Kind == IPVK_MemOPSize ? MaxNumMemOPAnnotations
                                              : MaxNumAnnotations);
     ValueSiteIndex++;
   }
 }
 
-// Create a COMDAT variable INSTR_PROF_RAW_VERSION_VAR to make the runtime
-// aware this is an ir_level profile so it can set the version flag.
-static void createIRLevelProfileFlagVariable(Module &M) {
-  Type *IntTy64 = Type::getInt64Ty(M.getContext());
-  uint64_t ProfileVersion = (INSTR_PROF_RAW_VERSION | VARIANT_MASK_IR_PROF);
-  auto IRLevelVersionVariable = new GlobalVariable(
-      M, IntTy64, true, GlobalVariable::ExternalLinkage,
-      Constant::getIntegerValue(IntTy64, APInt(64, ProfileVersion)),
-      INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR));
-  IRLevelVersionVariable->setVisibility(GlobalValue::DefaultVisibility);
-  Triple TT(M.getTargetTriple());
-  if (!TT.supportsCOMDAT())
-    IRLevelVersionVariable->setLinkage(GlobalValue::WeakAnyLinkage);
-  else
-    IRLevelVersionVariable->setComdat(M.getOrInsertComdat(
-        StringRef(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR))));
-}
-
 // Collect the set of members for each Comdat in module M and store
 // in ComdatMembers.
 static void collectComdatMembers(
     Module &M,
     std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers) {
   if (!DoComdatRenaming)
     return;
   for (Function &F : M)
     if (Comdat *C = F.getComdat())
       ComdatMembers.insert(std::make_pair(C, &F));
   for (GlobalVariable &GV : M.globals())
     if (Comdat *C = GV.getComdat())
       ComdatMembers.insert(std::make_pair(C, &GV));
   for (GlobalAlias &GA : M.aliases())
     if (Comdat *C = GA.getComdat())
       ComdatMembers.insert(std::make_pair(C, &GA));
 }
 
 static bool InstrumentAllFunctions(
     Module &M, function_ref<BranchProbabilityInfo *(Function &)> LookupBPI,
-    function_ref<BlockFrequencyInfo *(Function &)> LookupBFI) {
-  createIRLevelProfileFlagVariable(M);
+    function_ref<BlockFrequencyInfo *(Function &)> LookupBFI, bool IsCS) {
+  // For the context-sensitve instrumentation, we should have a separated pass
+  // (before LTO/ThinLTO linking) to create these variables.
+  if (!IsCS)
+    createIRLevelProfileFlagVar(M, /* IsCS */ false);
   std::unordered_multimap<Comdat *, GlobalValue *> ComdatMembers;
   collectComdatMembers(M, ComdatMembers);
 
   for (auto &F : M) {
     if (F.isDeclaration())
       continue;
     auto *BPI = LookupBPI(F);
     auto *BFI = LookupBFI(F);
-    instrumentOneFunc(F, &M, BPI, BFI, ComdatMembers);
+    instrumentOneFunc(F, &M, BPI, BFI, ComdatMembers, IsCS);
   }
   return true;
 }
 
 bool PGOInstrumentationGenLegacyPass::runOnModule(Module &M) {
   if (skipModule(M))
     return false;
 
   auto LookupBPI = [this](Function &F) {
     return &this->getAnalysis<BranchProbabilityInfoWrapperPass>(F).getBPI();
   };
   auto LookupBFI = [this](Function &F) {
     return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI();
   };
-  return InstrumentAllFunctions(M, LookupBPI, LookupBFI);
+  return InstrumentAllFunctions(M, LookupBPI, LookupBFI, IsCS);
 }
 
 PreservedAnalyses PGOInstrumentationGen::run(Module &M,
                                              ModuleAnalysisManager &AM) {
   auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
   auto LookupBPI = [&FAM](Function &F) {
     return &FAM.getResult<BranchProbabilityAnalysis>(F);
   };
 
   auto LookupBFI = [&FAM](Function &F) {
     return &FAM.getResult<BlockFrequencyAnalysis>(F);
   };
 
-  if (!InstrumentAllFunctions(M, LookupBPI, LookupBFI))
+  if (!InstrumentAllFunctions(M, LookupBPI, LookupBFI, IsCS))
     return PreservedAnalyses::all();
 
   return PreservedAnalyses::none();
 }
 
 static bool annotateAllFunctions(
     Module &M, StringRef ProfileFileName, StringRef ProfileRemappingFileName,
     function_ref<BranchProbabilityInfo *(Function &)> LookupBPI,
-    function_ref<BlockFrequencyInfo *(Function &)> LookupBFI) {
+    function_ref<BlockFrequencyInfo *(Function &)> LookupBFI, bool IsCS) {
   LLVM_DEBUG(dbgs() << "Read in profile counters: ");
   auto &Ctx = M.getContext();
   // Read the counter array from file.
   auto ReaderOrErr =
       IndexedInstrProfReader::create(ProfileFileName, ProfileRemappingFileName);
   if (Error E = ReaderOrErr.takeError()) {
     handleAllErrors(std::move(E), [&](const ErrorInfoBase &EI) {
       Ctx.diagnose(
           DiagnosticInfoPGOProfile(ProfileFileName.data(), EI.message()));
     });
     return false;
   }
 
   std::unique_ptr<IndexedInstrProfReader> PGOReader =
       std::move(ReaderOrErr.get());
   if (!PGOReader) {
     Ctx.diagnose(DiagnosticInfoPGOProfile(ProfileFileName.data(),
                                           StringRef("Cannot get PGOReader")));
     return false;
   }
+  if (!PGOReader->hasCSIRLevelProfile() && IsCS)
+    return false;
+
   // TODO: might need to change the warning once the clang option is finalized.
   if (!PGOReader->isIRLevelProfile()) {
     Ctx.diagnose(DiagnosticInfoPGOProfile(
         ProfileFileName.data(), "Not an IR level instrumentation profile"));
     return false;
   }
 
   std::unordered_multimap<Comdat *, GlobalValue *> ComdatMembers;
   collectComdatMembers(M, ComdatMembers);
   std::vector<Function *> HotFunctions;
   std::vector<Function *> ColdFunctions;
   for (auto &F : M) {
     if (F.isDeclaration())
       continue;
     auto *BPI = LookupBPI(F);
     auto *BFI = LookupBFI(F);
     // Split indirectbr critical edges here before computing the MST rather than
     // later in getInstrBB() to avoid invalidating it.
     SplitIndirectBrCriticalEdges(F, BPI, BFI);
-    PGOUseFunc Func(F, &M, ComdatMembers, BPI, BFI);
+    PGOUseFunc Func(F, &M, ComdatMembers, BPI, BFI, IsCS);
     bool AllZeros = false;
     if (!Func.readCounters(PGOReader.get(), AllZeros))
       continue;
     if (AllZeros) {
       F.setEntryCount(ProfileCount(0, Function::PCT_Real));
       if (Func.getProgramMaxCount() != 0)
         ColdFunctions.push_back(&F);
       continue;
if (PGOViewRawCounts != PGOVCT_None &&
         else
           ViewGraph(&Func, Twine("PGORawCounts_") + Func.getFunc().getName());
       else if (PGOViewRawCounts == PGOVCT_Text) {
         dbgs() << "pgo-view-raw-counts: " << Func.getFunc().getName() << "\n";
         Func.dumpInfo();
       }
     }
   }
-  M.setProfileSummary(PGOReader->getSummary().getMD(M.getContext()));
+  M.setProfileSummary(PGOReader->getSummary(IsCS).getMD(M.getContext()),
+                      IsCS ? ProfileSummary::PSK_CSInstr
+                           : ProfileSummary::PSK_Instr);
+
   // Set function hotness attribute from the profile.
   // We have to apply these attributes at the end because their presence
   // can affect the BranchProbabilityInfo of any callers, resulting in an
   // inconsistent MST between prof-gen and prof-use.
   for (auto &F : HotFunctions) {
     F->addFnAttr(Attribute::InlineHint);
     LLVM_DEBUG(dbgs() << "Set inline attribute to function: " << F->getName()
                       << "\n");
   }
   for (auto &F : ColdFunctions) {
     F->addFnAttr(Attribute::Cold);
     LLVM_DEBUG(dbgs() << "Set cold attribute to function: " << F->getName()
                       << "\n");
   }
   return true;
 }
 
 PGOInstrumentationUse::PGOInstrumentationUse(std::string Filename,
-                                             std::string RemappingFilename)
+                                             std::string RemappingFilename,
+                                             bool IsCS)
     : ProfileFileName(std::move(Filename)),
-      ProfileRemappingFileName(std::move(RemappingFilename)) {
+      ProfileRemappingFileName(std::move(RemappingFilename)), IsCS(IsCS) {
   if (!PGOTestProfileFile.empty())
     ProfileFileName = PGOTestProfileFile;
   if (!PGOTestProfileRemappingFile.empty())
     ProfileRemappingFileName = PGOTestProfileRemappingFile;
 }
 
 PreservedAnalyses PGOInstrumentationUse::run(Module &M,
                                              ModuleAnalysisManager &AM) {
 
   auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
   auto LookupBPI = [&FAM](Function &F) {
     return &FAM.getResult<BranchProbabilityAnalysis>(F);
   };
 
   auto LookupBFI = [&FAM](Function &F) {
     return &FAM.getResult<BlockFrequencyAnalysis>(F);
   };
 
   if (!annotateAllFunctions(M, ProfileFileName, ProfileRemappingFileName,
-                            LookupBPI, LookupBFI))
+                            LookupBPI, LookupBFI, IsCS))
     return PreservedAnalyses::all();
 
   return PreservedAnalyses::none();
 }
 
 bool PGOInstrumentationUseLegacyPass::runOnModule(Module &M) {
   if (skipModule(M))
     return false;
 
   auto LookupBPI = [this](Function &F) {
     return &this->getAnalysis<BranchProbabilityInfoWrapperPass>(F).getBPI();
   };
   auto LookupBFI = [this](Function &F) {
     return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI();
   };
 
-  return annotateAllFunctions(M, ProfileFileName, "", LookupBPI, LookupBFI);
+  return annotateAllFunctions(M, ProfileFileName, "", LookupBPI, LookupBFI,
+                              IsCS);
 }
 
 static std::string getSimpleNodeName(const BasicBlock *Node) {
   if (!Node->getName().empty())
     return Node->getName();
 
   std::string SimpleNodeName;
   raw_string_ostream OS(SimpleNodeName);

tools/gold/gold-plugin.cpp

#endif
   static std::string dwo_dir;
   /// Statistics output filename.
   static std::string stats_file;
 
   // Optimization remarks filename and hotness options
   static std::string OptRemarksFilename;
   static bool OptRemarksWithHotness = false;
 
+  // Context sensitive PGO options.
+  static std::string cs_profile_path;
+  static bool cs_pgo_gen = false;
+
   static void process_plugin_option(const char *opt_)
   {
     if (opt_ == nullptr)
       return;
     llvm::StringRef opt = opt_;
 
     if (opt.startswith("mcpu=")) {
       mcpu = opt.substr(strlen("mcpu="));
if (opt.startswith("mcpu=")) {
         message(LDPL_FATAL, "Invalid parallelism level: %s", opt_ + 5);
     } else if (opt.startswith("lto-partitions=")) {
       if (opt.substr(strlen("lto-partitions="))
               .getAsInteger(10, ParallelCodeGenParallelismLevel))
         message(LDPL_FATAL, "Invalid codegen partition level: %s", opt_ + 5);
     } else if (opt == "disable-verify") {
       DisableVerify = true;
     } else if (opt.startswith("sample-profile=")) {
-      sample_profile= opt.substr(strlen("sample-profile="));
+      sample_profile = opt.substr(strlen("sample-profile="));
+    } else if (opt == "cs-profile-generate") {
+      cs_pgo_gen = true;
+    } else if (opt.startswith("cs-profile-path=")) {
+      cs_profile_path = opt.substr(strlen("cs-profile-path="));
     } else if (opt == "new-pass-manager") {
       new_pass_manager = true;
     } else if (opt == "debug-pass-manager") {
       debug_pass_manager = true;
     } else if (opt.startswith("dwo_dir=")) {
       dwo_dir = opt.substr(strlen("dwo_dir="));
     } else if (opt.startswith("opt-remarks-filename=")) {
       OptRemarksFilename = opt.substr(strlen("opt-remarks-filename="));
static std::unique_ptr<LTO> createLTO(IndexWriteCallback OnIndexWrite,
   case options::OT_ASM_ONLY:
     Conf.CGFileType = TargetMachine::CGFT_AssemblyFile;
     break;
   }
 
   if (!options::sample_profile.empty())
     Conf.SampleProfile = options::sample_profile;
 
+  if (!options::cs_profile_path.empty())
+    Conf.CSIRProfile = options::cs_profile_path;
+  Conf.RunCSIRInstr = options::cs_pgo_gen;
+
   Conf.DwoDir = options::dwo_dir;
 
   // Set up optimization remarks handling.
   Conf.RemarksFilename = options::OptRemarksFilename;
   Conf.RemarksWithHotness = options::OptRemarksWithHotness;
 
   // Use new pass manager if set in driver
   Conf.UseNewPM = options::new_pass_manager;

tools/llvm-profdata/llvm-profdata.cpp

if (Error E = ReaderOrErr.takeError()) {
     instrprof_error IPE = InstrProfError::take(std::move(E));
     if (IPE != instrprof_error::empty_raw_profile)
       WC->Err = make_error<InstrProfError>(IPE);
     return;
   }
 
   auto Reader = std::move(ReaderOrErr.get());
   bool IsIRProfile = Reader->isIRLevelProfile();
-  if (WC->Writer.setIsIRLevelProfile(IsIRProfile)) {
+  bool HasCSIRProfile = Reader->hasCSIRLevelProfile();
+  if (WC->Writer.setIsIRLevelProfile(IsIRProfile, HasCSIRProfile)) {
     WC->Err = make_error<StringError>(
         "Merge IR generated profile with Clang generated profile.",
         std::error_code());
     return;
   }
 
   for (auto &I : *Reader) {
     if (Remapper)
       I.Name = (*Remapper)(I.Name);
if (Stats.ValueSitesHistogram[I] > 0)
       OS << "\t" << I + 1 << ", " << Stats.ValueSitesHistogram[I] << "\n";
   }
 }
 
 static int showInstrProfile(const std::string &Filename, bool ShowCounts,
                             uint32_t TopN, bool ShowIndirectCallTargets,
                             bool ShowMemOPSizes, bool ShowDetailedSummary,
                             std::vector<uint32_t> DetailedSummaryCutoffs,
-                            bool ShowAllFunctions, uint64_t ValueCutoff,
-                            bool OnlyListBelow, const std::string &ShowFunction,
-                            bool TextFormat, raw_fd_ostream &OS) {
+                            bool ShowAllFunctions, bool ShowCS,
+                            uint64_t ValueCutoff, bool OnlyListBelow,
+                            const std::string &ShowFunction, bool TextFormat,
+                            raw_fd_ostream &OS) {
   auto ReaderOrErr = InstrProfReader::create(Filename);
   std::vector<uint32_t> Cutoffs = std::move(DetailedSummaryCutoffs);
   if (ShowDetailedSummary && Cutoffs.empty()) {
     Cutoffs = {800000, 900000, 950000, 990000, 999000, 999900, 999990};
   }
   InstrProfSummaryBuilder Builder(std::move(Cutoffs));
   if (Error E = ReaderOrErr.takeError())
     exitWithError(std::move(E), Filename);
OS << "The list of functions with the maximum counter less than "
        << ValueCutoff << ":\n";
   }
 
   // Add marker so that IR-level instrumentation round-trips properly.
   if (TextFormat && IsIRInstr)
     OS << ":ir\n";
 
   for (const auto &Func : *Reader) {
+    if (Reader->isIRLevelProfile() && Reader->hasCSIRLevelProfile()) {
+      bool FuncIsCS = NamedInstrProfRecord::hasCSFlagInHash(Func.Hash);
+      if (FuncIsCS != ShowCS)
+        continue;
+    }
     bool Show =
         ShowAllFunctions || (!ShowFunction.empty() &&
                              Func.Name.find(ShowFunction) != Func.Name.npos);
 
     bool doTextFormatDump = (Show && TextFormat);
 
     if (doTextFormatDump) {
       InstrProfSymtab &Symtab = Reader->getSymtab();
cl::opt<bool> ShowDetailedSummary("detailed-summary", cl::init(false),
                                     cl::desc("Show detailed profile summary"));
   cl::list<uint32_t> DetailedSummaryCutoffs(
       cl::CommaSeparated, "detailed-summary-cutoffs",
       cl::desc(
           "Cutoff percentages (times 10000) for generating detailed summary"),
       cl::value_desc("800000,901000,999999"));
   cl::opt<bool> ShowAllFunctions("all-functions", cl::init(false),
                                  cl::desc("Details for every function"));
+  cl::opt<bool> ShowCS("showcs", cl::init(false),
+                       cl::desc("Show context sensitive counts"));
   cl::opt<std::string> ShowFunction("function",
                                     cl::desc("Details for matching functions"));
 
   cl::opt<std::string> OutputFilename("output", cl::value_desc("output"),
                                       cl::init("-"), cl::desc("Output file"));
   cl::alias OutputFilenameA("o", cl::desc("Alias for --output"),
                             cl::aliasopt(OutputFilename));
   cl::opt<ProfileKinds> ProfileKind(
if (ShowAllFunctions && !ShowFunction.empty())
     WithColor::warning() << "-function argument ignored: showing all functions\n";
 
   std::vector<uint32_t> Cutoffs(DetailedSummaryCutoffs.begin(),
                                 DetailedSummaryCutoffs.end());
   if (ProfileKind == instr)
     return showInstrProfile(Filename, ShowCounts, TopNFunctions,
                             ShowIndirectCallTargets, ShowMemOPSizes,
                             ShowDetailedSummary, DetailedSummaryCutoffs,
-                            ShowAllFunctions, ValueCutoff, OnlyListBelow,
-                            ShowFunction, TextFormat, OS);
+                            ShowAllFunctions, ShowCS, ValueCutoff,
+                            OnlyListBelow, ShowFunction, TextFormat, OS);
   else
     return showSampleProfile(Filename, ShowCounts, ShowAllFunctions,
                              ShowFunction, OS);
 }
 
 int main(int argc, const char *argv[]) {
   InitLLVM X(argc, argv);
 

tools/opt/NewPMDriver.h

enum VerifierKind {
   VK_VerifyEachPass
 };
 enum PGOKind {
   NoPGO,
   InstrGen,
   InstrUse,
   SampleUse
 };
+enum CSPGOKind { NoCSPGO, CSInstrGen, CSInstrUse };
 }
 
 /// Driver function to run the new pass manager over a module.
 ///
 /// This function only exists factored away from opt.cpp in order to prevent
 /// inclusion of the new pass manager headers and the old headers into the same
 /// file. It's interface is consequentially somewhat ad-hoc, but will go away
 /// when the transition finishes.

tools/opt/NewPMDriver.cpp

static cl::opt<std::string> PipelineStartEPPipeline(
     cl::Hidden);
 static cl::opt<std::string> OptimizerLastEPPipeline(
     "passes-ep-optimizer-last",
     cl::desc("A textual description of the function pass pipeline inserted at "
              "the OptimizerLast extension point into default pipelines"),
     cl::Hidden);
 
 extern cl::opt<PGOKind> PGOKindFlag;
 extern cl::opt<std::string> ProfileFile;
+extern cl::opt<CSPGOKind> CSPGOKindFlag;
+extern cl::opt<std::string> CSProfileGenFile;
+
 static cl::opt<std::string>
     ProfileRemappingFile("profile-remapping-file",
                          cl::desc("Path to the profile remapping file."),
                          cl::Hidden);
 static cl::opt<bool> DebugInfoForProfiling(
     "new-pm-debug-info-for-profiling", cl::init(false), cl::Hidden,
     cl::desc("Emit special debug info to enable PGO profile generation."));
 /// @}}
bool llvm::runPassPipeline(StringRef Arg0, Module &M, TargetMachine *TM,
                            StringRef PassPipeline, OutputKind OK,
                            VerifierKind VK,
                            bool ShouldPreserveAssemblyUseListOrder,
                            bool ShouldPreserveBitcodeUseListOrder,
                            bool EmitSummaryIndex, bool EmitModuleHash,
                            bool EnableDebugify) {
   bool VerifyEachPass = VK == VK_VerifyEachPass;
 
   Optional<PGOOptions> P;
   switch (PGOKindFlag) {
     case InstrGen:
-      P = PGOOptions(ProfileFile, "", "", "", true);
+      P = PGOOptions(ProfileFile, "", "", PGOOptions::IRInstr);
       break;
     case InstrUse:
-      P = PGOOptions("", ProfileFile, "", ProfileRemappingFile, false);
+      P = PGOOptions(ProfileFile, "", ProfileRemappingFile, PGOOptions::IRUse);
       break;
     case SampleUse:
-      P = PGOOptions("", "", ProfileFile, ProfileRemappingFile, false);
+      P = PGOOptions(ProfileFile, "", ProfileRemappingFile,
+                     PGOOptions::SampleUse);
       break;
     case NoPGO:
       if (DebugInfoForProfiling)
-        P = PGOOptions("", "", "", "", false, true);
+        P = PGOOptions("", "", "", PGOOptions::NoAction, PGOOptions::NoCSAction,
+                       true);
       else
         P = None;
     }
+    if (CSPGOKindFlag != NoCSPGO) {
+      if (P && (P->Action == PGOOptions::IRInstr ||
+                P->Action == PGOOptions::SampleUse))
+        errs() << "CSPGOKind cannot be used with IRInstr or SampleUse";
+      if (CSPGOKindFlag == CSInstrGen) {
+        if (CSProfileGenFile.empty())
+          errs() << "CSInstrGen needs to specify CSProfileGenFile";
+        if (P) {
+          P->CSAction = PGOOptions::CSIRInstr;
+          P->CSProfileGenFile = CSProfileGenFile;
+        } else
+          P = PGOOptions("", CSProfileGenFile, ProfileRemappingFile,
+                         PGOOptions::NoAction, PGOOptions::CSIRInstr);
+      } else /* CSPGOKindFlag == CSInstrUse */ {
+        if (!P)
+          errs() << "CSInstrUse needs to be together with InstrUse";
+        P->CSAction = PGOOptions::CSIRUse;
+      }
+    }
   PassInstrumentationCallbacks PIC;
   StandardInstrumentations SI;
   SI.registerCallbacks(PIC);
 
   PassBuilder PB(TM, P, &PIC);
   registerEPCallbacks(PB, VerifyEachPass, DebugPM);
 
   // Load requested pass plugins and let them register pass builder callbacks

tools/opt/opt.cpp

PGOKindFlag("pgo-kind", cl::init(NoPGO), cl::Hidden,
                                       "Instrument the IR to generate profile."),
                            clEnumValN(InstrUse, "pgo-instr-use-pipeline",
                                       "Use instrumented profile to guide PGO."),
                            clEnumValN(SampleUse, "pgo-sample-use-pipeline",
                                       "Use sampled profile to guide PGO.")));
 cl::opt<std::string> ProfileFile("profile-file",
                                  cl::desc("Path to the profile."), cl::Hidden);
 
+cl::opt<CSPGOKind> CSPGOKindFlag(
+    "cspgo-kind", cl::init(NoCSPGO), cl::Hidden,
+    cl::desc("The kind of context sensitive profile guided optimization"),
+    cl::values(
+        clEnumValN(NoCSPGO, "nocspgo", "Do not use CSPGO."),
+        clEnumValN(
+            CSInstrGen, "new-pm-cspgo-instr-gen-pipeline",
+            "Instrument (context sensitive) the IR to generate profile."),
+        clEnumValN(
+            CSInstrUse, "new-pm-cspgo-instr-use-pipeline",
+            "Use instrumented (context sensitive) profile to guide PGO.")));
+cl::opt<std::string> CSProfileGenFile(
+    "cs-profilegen-file",
+    cl::desc("Path to the instrumented context sensitive profile."),
+    cl::Hidden);
+
 class OptCustomPassManager : public legacy::PassManager {
   DebugifyStatsMap DIStatsMap;
 
 public:
   using super = legacy::PassManager;
 
   void add(Pass *P) override {
     // Wrap each pass with (-check)-debugify passes if requested, making

unittests/ProfileData/InstrProfTest.cpp

auto VerifySummary = [](ProfileSummary &IPS) mutable {
     auto NinetyFivePerc = find_if(Details, Predicate);
     Cutoff = 990000;
     auto NinetyNinePerc = find_if(Details, Predicate);
     ASSERT_EQ(576460752303423488U, EightyPerc->MinCount);
     ASSERT_EQ(288230376151711744U, NinetyPerc->MinCount);
     ASSERT_EQ(288230376151711744U, NinetyFivePerc->MinCount);
     ASSERT_EQ(72057594037927936U, NinetyNinePerc->MinCount);
   };
-  ProfileSummary &PS = Reader->getSummary();
+  ProfileSummary &PS = Reader->getSummary(/* IsCS */ false);
   VerifySummary(PS);
 
   // Test that conversion of summary to and from Metadata works.
   LLVMContext Context;
   Metadata *MD = PS.getMD(Context);
   ASSERT_TRUE(MD);
   ProfileSummary *PSFromMD = ProfileSummary::getFromMD(MD);
   ASSERT_TRUE(PSFromMD);
   VerifySummary(*PSFromMD);
   delete PSFromMD;
 
   // Test that summary can be attached to and read back from module.
   Module M("my_module", Context);
-  M.setProfileSummary(MD);
-  MD = M.getProfileSummary();
+  M.setProfileSummary(MD, ProfileSummary::PSK_Instr);
+  MD = M.getProfileSummary(ProfileSummary::PSK_Instr);
   ASSERT_TRUE(MD);
   PSFromMD = ProfileSummary::getFromMD(MD);
   ASSERT_TRUE(PSFromMD);
   VerifySummary(*PSFromMD);
   delete PSFromMD;
 }
 
 TEST_F(InstrProfTest, test_writer_merge) {

 
 TEST_P(MaybeSparseInstrProfTest, get_max_function_count) {
   Writer.addRecord({"foo", 0x1234, {1ULL << 31, 2}}, Err);
   Writer.addRecord({"bar", 0, {1ULL << 63}}, Err);
   Writer.addRecord({"baz", 0x5678, {0, 0, 0, 0}}, Err);
   auto Profile = Writer.writeBuffer();
   readProfile(std::move(Profile));
 
-  ASSERT_EQ(1ULL << 63, Reader->getMaximumFunctionCount());
+  ASSERT_EQ(1ULL << 63, Reader->getMaximumFunctionCount(/* IsCS */ false));
 }
 
 TEST_P(MaybeSparseInstrProfTest, get_weighted_function_counts) {
   Writer.addRecord({"foo", 0x1234, {1, 2}}, 3, Err);
   Writer.addRecord({"foo", 0x1235, {3, 4}}, 5, Err);
   auto Profile = Writer.writeBuffer();
   readProfile(std::move(Profile));
 

unittests/ProfileData/SampleProfTest.cpp

void testRoundTrip(SampleProfileFormat Format, bool Remap) {
     Metadata *MD = Summary.getMD(Context);
     ASSERT_TRUE(MD);
     ProfileSummary *PS = ProfileSummary::getFromMD(MD);
     ASSERT_TRUE(PS);
     VerifySummary(*PS);
     delete PS;
 
     // Test that summary can be attached to and read back from module.
-    M.setProfileSummary(MD);
-    MD = M.getProfileSummary();
+    M.setProfileSummary(MD, ProfileSummary::PSK_Sample);
+    MD = M.getProfileSummary(ProfileSummary::PSK_Sample);
     ASSERT_TRUE(MD);
     PS = ProfileSummary::getFromMD(MD);
     ASSERT_TRUE(PS);
     VerifySummary(*PS);
     delete PS;
   }
 };