Commit Graph

235 Commits

Author SHA1 Message Date
Ellis Hoag 800bf8ed29 [InstrProf] Attach debug info to counters
Add the llvm flag `-debug-info-correlate` to attach debug info to instrumentation counters so we can correlate raw profile data to their functions. Raw profiles are dumped as `.proflite` files. The next diff enables `llvm-profdata` to consume `.proflite` and debug info files to produce a normal `.profdata` profile.

Part of the "lightweight instrumentation" work: https://groups.google.com/g/llvm-dev/c/r03Z6JoN7d4

Reviewed By: kyulee

Differential Revision: https://reviews.llvm.org/D114565
2021-12-13 17:51:22 -08:00
Rong Xu ad2e5be4be [PGO] Adjust BFI verification option default values [NFC]
Slightly changed the default option values.
Also avoided some bogus output.
2021-12-09 14:15:28 -08:00
Mircea Trofin a32c2c3808 [NFC] Use Optional<ProfileCount> to model invalid counts
ProfileCount could model invalid values, but a user had no indication
that the getCount method could return bogus data. Optional<ProfileCount>
addresses that, because the user must dereference the optional. In
addition, the patch removes concept duplication.

Differential Revision: https://reviews.llvm.org/D113839
2021-11-14 19:03:30 -08:00
Rong Xu de620f5b13 [CSPGO] Fix lost IRPGOFlag in CSPGO instrumentation
The IRPGOFlag symbol (__llvm_profile_raw_version) is dropped when
identified as non-prevailing for either regular or thin LTO during
the mixed-LTO mode compilation. This happens in the module where
IRPGOFlag is marked as non-prevailing. This variable
is emitted in the final object from the prevailing module.

This is still problematic because we currently query this symbol
to coordinate some actions between PGOInstrumentation pass
and InstrProfiling lowering pass, like whether to do value
profiling, whether to do comdat renaming.

This problem is bought up by YolandaCY in
https://reviews.llvm.org/D107034
YolandCY reported unresolved symbol linker errors in
CSPGO instrumentation build for chromium.

This patch let LTO retain IRPGOFlag decl by adding it to
CompilerUsed list and relax the check in isIRPGOFlagSet() when
doing the InstrProfiling lowering.

The test case in the patch is from D107034
<https://reviews.llvm.org/D107034>.

Differential Revision: https://reviews.llvm.org/D108581
2021-08-24 09:41:29 -07:00
Yolanda Chen 8fa16cc628 [LTO][lld] Add lto-pgo-warn-mismatch option
When enable CSPGO for ThinLTO, there are profile cfg mismatch warnings that will cause lld-link errors (with /WX)
due to source changes (e.g. `#if` code runs for profile generation but not for profile use)
To disable it we have to use an internal "/mllvm:-no-pgo-warn-mismatch" option.
In contrast clang uses option ”-Wno-backend-plugin“ to avoid such warnings and gcc has an explicit "-Wno-coverage-mismatch" option.

Add "lto-pgo-warn-mismatch" option to lld COFF/ELF to help turn on/off the profile mismatch warnings explicitly when build with ThinLTO and CSPGO.

Differential Revision: https://reviews.llvm.org/D104431
2021-08-11 09:45:55 -07:00
Wang, Pengfei 6c4809825d Revert "[lld] Add lto-pgo-warn-mismatch option"
This reverts commit 0cfb00a1c9.
2021-08-11 16:25:42 +08:00
Yolanda Chen 0cfb00a1c9 [lld] Add lto-pgo-warn-mismatch option
When enable CSPGO for ThinLTO, there are profile cfg mismatch warnings that will cause lld-link errors (with /WX).
To disable it we have to use an internal "/mllvm:-no-pgo-warn-mismatch" option.
In contrast clang uses option ”-Wno-backend-plugin“ to avoid such warnings and gcc has an explicit "-Wno-coverage-mismatch" option.

Add this "lto-pgo-warn-mismatch" option to lld to help turn on/off the profile mismatch warnings explicitly when build with ThinLTO and CSPGO.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D104431
2021-08-11 14:43:26 +08:00
Fangrui Song d8aba75a76 Internalize some cl::opt global variables or move them under namespace llvm 2021-05-07 11:15:43 -07:00
Kazu Hirata 9dc62d1dc1 [PGO] Drop unnecessary const from return types (NFC) 2021-02-11 23:31:29 -08:00
Kazu Hirata ea3175c15b [Transforms/Instrumentation] Use range-based for loops (NFC) 2021-02-05 21:02:08 -08:00
Sriraman Tallam 9a81a4ef79 Emit metadata when instr. profiles hash mismatch occurs.
This patch emits "instr_prof_hash_mismatch" function annotation metadata if
there is a hash mismatch while applying instrumented profiles.

During the PGO optimized build using instrumented profiles, if the CFG of
the function has changed since generating the profile, a hash mismatch is
encountered. This patch emits this information as annotation metadata. We
plan to use this with Propeller which is done at the machine IR level.
Propeller is usually applied on top of PGO and a hash mismatch during
PGO could be used to detect source drift.

Differential Revision: https://reviews.llvm.org/D95495
2021-01-29 12:56:01 -08:00
Petr Hosek bb9eb19829 Support for instrumenting only selected files or functions
This change implements support for applying profile instrumentation
only to selected files or functions. The implementation uses the
sanitizer special case list format to select which files and functions
to instrument, and relies on the new noprofile IR attribute to exclude
functions from instrumentation.

Differential Revision: https://reviews.llvm.org/D94820
2021-01-26 17:13:34 -08:00
Petr Hosek 1e634f3952 Revert "Support for instrumenting only selected files or functions"
This reverts commit 4edf35f11a because
the test fails on Windows bots.
2021-01-26 12:25:28 -08:00
Petr Hosek 4edf35f11a Support for instrumenting only selected files or functions
This change implements support for applying profile instrumentation
only to selected files or functions. The implementation uses the
sanitizer special case list format to select which files and functions
to instrument, and relies on the new noprofile IR attribute to exclude
functions from instrumentation.

Differential Revision: https://reviews.llvm.org/D94820
2021-01-26 11:11:39 -08:00
Kazu Hirata 5d24935f22 [PGO] Remove dead member variable InstrumentFuncEntry (NFC)
This patch removes InstrumentFuncEntry as it is dead.

The constructor of FuncPGOInstrumentation passes InstrumentFuncEntry
to MST, but it doesn't make a local copy as a member variable.
2020-12-20 09:57:05 -08:00
Rong Xu 3733463dbb [IR][PGO] Add hot func attribute and use hot/cold attribute in func section
Clang FE currently has hot/cold function attribute. But we only have
cold function attribute in LLVM IR.

This patch adds support of hot function attribute to LLVM IR.  This
attribute will be used in setting function section prefix/suffix.
Currently .hot and .unlikely suffix only are added in PGO (Sample PGO)
compilation (through isFunctionHotInCallGraph and
isFunctionColdInCallGraph).

This patch changes the behavior. The new behavior is:
(1) If the user annotates a function as hot or isFunctionHotInCallGraph
    is true, this function will be marked as hot. Otherwise,
(2) If the user annotates a function as cold or
    isFunctionColdInCallGraph is true, this function will be marked as
    cold.

The changes are:
(1) user annotated function attribute will used in setting function
    section prefix/suffix.
(2) hot attribute overwrites profile count based hotness.
(3) profile count based hotness overwrite user annotated cold attribute.

The intention for these changes is to provide the user a way to mark
certain function as hot in cases where training input is hard to cover
all the hot functions.

Differential Revision: https://reviews.llvm.org/D92493
2020-12-17 18:41:12 -08:00
Rong Xu 0abd744597 [PGO] Use the sum of profile counts to fix the function entry count
Raw profile count values for each BB are not kept after profile
annotation. We record function entry count and branch weights
and use them to compute the count when needed.  This mechanism
works well in a perfect world, but often breaks in real programs,
because of number prevision, inconsistent profile, or bugs in
BFI). This patch uses sum of profile count values to fix
function entry count to make the BFI count close to real profile
counts.

Differential Revision: https://reviews.llvm.org/D61540
2020-12-16 13:37:43 -08:00
Rong Xu 54e03d03a7 [PGO] Verify BFI counts after loading profile data
This patch adds the functionality to compare BFI counts with real
profile
counts right after reading the profile. It will print remarks under
-Rpass-analysis=pgo, or the internal option -pass-remarks-analysis=pgo.

Differential Revision: https://reviews.llvm.org/D91813
2020-12-14 15:56:10 -08:00
Roman Lebedev 6861d938e5
Revert "clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM"
See discussion in https://bugs.llvm.org/show_bug.cgi?id=45073 / https://reviews.llvm.org/D66324#2334485
the implementation is known-broken for certain inputs,
the bugreport was up for a significant amount of timer,
and there has been no activity to address it.
Therefore, just completely rip out all of misexpect handling.

I suspect, fixing it requires redesigning the internals of MD_misexpect.
Should anyone commit to fixing the implementation problem,
starting from clean slate may be better anyways.

This reverts commit 7bdad08429,
and some of it's follow-ups, that don't stand on their own.
2020-11-14 13:12:38 +03:00
Arthur Eubanks 5c31b8b94f Revert "Use uint64_t for branch weights instead of uint32_t"
This reverts commit 10f2a0d662.

More uint64_t overflows.
2020-10-31 00:25:32 -07:00
Arthur Eubanks 10f2a0d662 Use uint64_t for branch weights instead of uint32_t
CallInst::updateProfWeight() creates branch_weights with i64 instead of i32.
To be more consistent everywhere and remove lots of casts from uint64_t
to uint32_t, use i64 for branch_weights.

Reviewed By: davidxl

Differential Revision: https://reviews.llvm.org/D88609
2020-10-30 10:03:46 -07:00
Nico Weber 2a4e704c92 Revert "Use uint64_t for branch weights instead of uint32_t"
This reverts commit e5766f25c6.
Makes clang assert when building Chromium, see https://crbug.com/1142813
for a repro.
2020-10-27 09:26:21 -04:00
Arthur Eubanks e5766f25c6 Use uint64_t for branch weights instead of uint32_t
CallInst::updateProfWeight() creates branch_weights with i64 instead of i32.
To be more consistent everywhere and remove lots of casts from uint64_t
to uint32_t, use i64 for branch_weights.

Reviewed By: davidxl

Differential Revision: https://reviews.llvm.org/D88609
2020-10-26 20:24:04 -07:00
Fangrui Song a0ffe2b21a [PGO] Skip if an IndirectBrInst critical edge cannot be split
PGOInstrumentation runs `SplitIndirectBrCriticalEdges` but some IndirectBrInst
critical edge cannot be split. `getInstrBB` will crash when calling `SplitCriticalEdge`, e.g.

  int foo(char *p) {
    void *targets[2];
    targets[0] = &&indirect;
    targets[1] = &&end;
    for (;; p++)
      if (*p == 7) {
  indirect:
        goto *targets[p[1]]; // the self loop is critical in -O
      }
  end:
    return 0;
  }

Skip such critical edges to prevent a crash.

Reviewed By: davidxl, lebedev.ri

Differential Revision: https://reviews.llvm.org/D87435
2020-09-10 11:04:14 -07:00
Fangrui Song 3b21a07fd7 [PGO] Delete dead comdat renaming code related to GlobalAlias. NFC
A GlobalAlias is an address-taken user of its aliased function.
canRenameComdatFunc has excluded such cases.

Reviewed By: davidxl

Differential Revision: https://reviews.llvm.org/D85597
2020-08-10 09:02:04 -07:00
Hiroshi Yamauchi 3d6f53018f [PGO] Include the mem ops into the function hash.
To avoid hash collisions when the only difference is in mem ops.
2020-07-30 09:26:20 -07:00
Hiroshi Yamauchi ae7589e1f1 Revert "[PGO] Include the mem ops into the function hash."
This reverts commit 120e66b341.

Due to a buildbot failure.
2020-07-29 15:04:57 -07:00
Hiroshi Yamauchi 120e66b341 [PGO] Include the mem ops into the function hash.
To avoid hash collisions when the only difference is in mem ops.

Differential Revision: https://reviews.llvm.org/D84782
2020-07-29 13:59:40 -07:00
Wei Mi a23f62343c Supplement instr profile with sample profile.
PGO profile is usually more precise than sample profile. However, PGO profile
needs to be collected from loadtest and loadtest may not be representative
enough to the production workload. Sample profile collected from production
can be used as a supplement -- for functions cold in loadtest but warm/hot
in production, we can scale up the related function in PGO profile if the
function is warm or hot in sample profile.

The implementation contains changes in compiler side and llvm-profdata side.
Given an instr profile and a sample profile, for a function cold in PGO
profile but warm/hot in sample profile, llvm-profdata will either mark
all the counters in the profile to be -1 or scale up the max count in the
function to be above hot threshold, depending on the zero counter ratio in
the profile. The assumption is if there are too many counters being zero
in the function profile, the profile is more likely to cause harm than good,
then llvm-profdata will mark all the counters to be -1 indicating the
function is hot but the profile is unaccountable. In compiler side, if a
function profile with all -1 counters is seen, the function entry count will
be set to be above hot threshold but its internal profile will be dropped.

In the long run, it may be useful to let compiler support using PGO profile
and sample profile at the same time, but that requires more careful design
and more substantial changes to make two profiles work seamlessly. The patch
here serves as a simple intermediate solution.

Differential Revision: https://reviews.llvm.org/D81981
2020-07-27 20:17:40 -07:00
Rong Xu 1dd39b1133 [PGO] Fix incorrect function entry count
Function entry count might be zero after the profile counts reset and
before reentry to the function.

Zero profile entry count is very bad as the profile count from BFI will
be wrong.

A simple fix is to set the profile entry count to 1 if there are
non-zero profile counts in this function.

Differential Revision: https://reviews.llvm.org/D84378
2020-07-24 17:39:55 -07:00
Rong Xu 5546c2ab42 Revert "[PGO][InstrProf] Do not promote count if the exit blocks contains ret instruction"
This reverts commit 6fdc6f6c7d.
2020-07-24 17:35:44 -07:00
Rong Xu 6fdc6f6c7d [PGO][InstrProf] Do not promote count if the exit blocks contains ret instruction
Skip profile count promotion if any of the ExitBlocks contains a ret
instruction. This is to prevent dumping of incomplete profile -- if the
the loop is a long running loop and dump is called in the middle
of the loop, the result profile is incomplete.

ExitBlocks containing a ret instruction is an indication of a long running
loop -- early exit to error handling code.

Differential Revision: https://reviews.llvm.org/D84379
2020-07-24 17:13:58 -07:00
Rong Xu 50da55a585 [PGO] Supporting code for always instrumenting entry block
This patch includes the supporting code that enables always
instrumenting the function entry block by default.

This patch will NOT the default behavior.

It adds a variant bit in the profile version, adds new directives in
text profile format, and changes llvm-profdata tool accordingly.

This patch is a split of D83024 (https://reviews.llvm.org/D83024)
Many test changes from D83024 are also included.

Differential Revision: https://reviews.llvm.org/D84261
2020-07-22 15:01:53 -07:00
Yevgeny Rouban dcfa78a4cc Extend InvokeInst !prof branch_weights metadata to unwind branches
Allow InvokeInst to have the second optional prof branch weight for
its unwind branch. InvokeInst is a terminator with two successors.
It might have its unwind branch taken many times. If so
the BranchProbabilityInfo unwind branch heuristic can be inaccurate.
This patch allows a higher accuracy calculated with both branch
weights set.

Changes:
 - A new section about InvokeInst is added to
   the BranchWeightMetadata page. It states the old information that
   missed in the doc and adds new about the second branch weight.
 - Verifier is changed to allow either 1 or 2 branch weights
   for InvokeInst.
 - A new test is written for BranchProbabilityInfo to demonstrate
   the main improvement of the simple fix in calcMetadataWeights().
 - Several new testcases are created for Inliner. Those check that
    both weights are accounted for invoke instruction weight
    calculation.
 - PGOUseFunc::setBranchWeights() is fixed to be applicable to
   InvokeInst.

Reviewers: davidxl, reames, xur, yamauchi
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80618
2020-06-04 15:37:15 +07:00
Mircea Trofin fa3b587196 [llvm]NFC] Simplify ProfileSummaryInfo state transitions
ProfileSummaryInfo is updated seldom, as result of very specific
triggers. This patch clearly demarcates state updates from read-only uses.
This, arguably, improves readability and maintainability.
2020-05-27 11:58:37 -07:00
Hiroshi Yamauchi 106ec64fbc [PGO] Add memcmp/bcmp size value profiling.
Summary: This adds support for memcmp/bcmp to the existing memcpy/memset value profiling.

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79751
2020-05-26 10:28:04 -07:00
Craig Topper cbe77ca9bd [CallSite removal] Remove unneeded includes of CallSite.h. NFC 2020-04-23 21:01:48 -07:00
Alina Sbirlea 3abcbf9903 [CFG/BasicBlock] Rename succ_const to const_succ. [NFC]
Summary:
Rename `succ_const_iterator` to `const_succ_iterator` and
`succ_const_range` to `const_succ_range` for consistency with the
predecessor iterators, and the corresponding iterators in
MachineBasicBlock.

Reviewers: nicholas, dblaikie, nlewycky

Subscribers: hiraditya, bmahjour, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75952
2020-03-25 12:40:55 -07:00
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

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

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
Andy Kaylor b35b7da460 [PGO] Attach appropriate funclet operand bundles to value profiling instrumentation calls
Patch by Chris Chrulski

When generating value profiling instrumentation, ensure the call gets the
correct funclet token, otherwise WinEHPrepare will turn the call (and all
subsequent instructions) into unreachable.

Differential Revision: https://reviews.llvm.org/D73221
2020-01-24 11:20:53 -08:00
Reid Kleckner 05da2fe521 Sink all InitializePasses.h includes
This file lists every pass in LLVM, and is included by Pass.h, which is
very popular. Every time we add, remove, or rename a pass in LLVM, it
caused lots of recompilation.

I found this fact by looking at this table, which is sorted by the
number of times a file was changed over the last 100,000 git commits
multiplied by the number of object files that depend on it in the
current checkout:
  recompiles    touches affected_files  header
  342380        95      3604    llvm/include/llvm/ADT/STLExtras.h
  314730        234     1345    llvm/include/llvm/InitializePasses.h
  307036        118     2602    llvm/include/llvm/ADT/APInt.h
  213049        59      3611    llvm/include/llvm/Support/MathExtras.h
  170422        47      3626    llvm/include/llvm/Support/Compiler.h
  162225        45      3605    llvm/include/llvm/ADT/Optional.h
  158319        63      2513    llvm/include/llvm/ADT/Triple.h
  140322        39      3598    llvm/include/llvm/ADT/StringRef.h
  137647        59      2333    llvm/include/llvm/Support/Error.h
  131619        73      1803    llvm/include/llvm/Support/FileSystem.h

Before this change, touching InitializePasses.h would cause 1345 files
to recompile. After this change, touching it only causes 550 compiles in
an incremental rebuild.

Reviewers: bkramer, asbirlea, bollu, jdoerfert

Differential Revision: https://reviews.llvm.org/D70211
2019-11-13 16:34:37 -08:00
Hans Wennborg 1e1e3ba252 Unify the two CRC implementations
David added the JamCRC implementation in r246590. More recently, Eugene
added a CRC-32 implementation in r357901, which falls back to zlib's
crc32 function if present.

These checksums are essentially the same, so having multiple
implementations seems unnecessary. This replaces the CRC-32
implementation with the simpler one from JamCRC, and implements the
JamCRC interface in terms of CRC-32 since this means it can use zlib's
implementation when available, saving a few bytes and potentially making
it faster.

JamCRC took an ArrayRef<char> argument, and CRC-32 took a StringRef.
This patch changes it to ArrayRef<uint8_t> which I think is the best
choice, and simplifies a few of the callers nicely.

Differential revision: https://reviews.llvm.org/D68570

llvm-svn: 374148
2019-10-09 09:06:30 +00:00
Bardia Mahjour f6c34de117 [PGO] Refactor Value Profiling into a plugin based oracle and create a well defined API for the plugins.
Summary: This PR creates a utility class called ValueProfileCollector that tells PGOInstrumentationGen and PGOInstrumentationUse what to value-profile and where to attach the profile metadata. It then refactors logic scattered in PGOInstrumentation.cpp into two plugins that plug into the ValueProfileCollector.

Authored By: Wael Yehia <wyehia@ca.ibm.com>

Reviewer: davidxl, tejohnson, xur

Reviewed By: davidxl, tejohnson, xur

Subscribers: llvm-commits

Tag: #llvm

Differential Revision: https://reviews.llvm.org/D67920

Patch By Wael Yehia <wyehia@ca.ibm.com>

llvm-svn: 373601
2019-10-03 14:20:50 +00:00
Teresa Johnson fd2044f299 [PGO] Change hardcoded thresholds for cold/inlinehint to use summary
Summary:
The PGO counter reading will add cold and inlinehint (hot) attributes
to functions that are very cold or hot. This was using hardcoded
thresholds, instead of the profile summary cutoffs which are used in
other hot/cold detection and are more dynamic and adaptable. Switch
to using the summary-based cold/hot detection.

The hardcoded limits were causing some code that had a medium level of
hotness (per the summary) to be incorrectly marked with a cold
attribute, blocking inlining.

Reviewers: davidxl

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67673

llvm-svn: 372189
2019-09-17 23:12:13 +00:00
Petr Hosek 7bdad08429 Reland "clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM"
This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300

We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.

We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.

A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.

In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect

Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324

llvm-svn: 371635
2019-09-11 16:19:50 +00:00
Dmitri Gribenko 57256af307 Revert "clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM"
This reverts commit r371584. It introduced a dependency from compiler-rt
to llvm/include/ADT, which is problematic for multiple reasons.

One is that it is a novel dependency edge, which needs cross-compliation
machinery for llvm/include/ADT (yes, it is true that right now
compiler-rt included only header-only libraries, however, if we allow
compiler-rt to depend on anything from ADT, other libraries will
eventually get used).

Secondly, depending on ADT from compiler-rt exposes ADT symbols from
compiler-rt, which would cause ODR violations when Clang is built with
the profile library.

llvm-svn: 371598
2019-09-11 09:16:17 +00:00
Petr Hosek 394a8ed8f1 clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM
This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300

We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.

We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.

A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.

In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect

Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324

llvm-svn: 371584
2019-09-11 01:09:16 +00:00
Petr Hosek 7d1757aba8 Revert "clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM"
This reverts commit r371484: this broke sanitizer-x86_64-linux-fast bot.

llvm-svn: 371488
2019-09-10 06:25:13 +00:00
Petr Hosek a10802fd73 clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM
This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300

We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.

We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.

A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.

In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect

Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324

llvm-svn: 371484
2019-09-10 03:11:39 +00:00
Jonas Devlieghere 0eaee545ee [llvm] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013
2019-08-15 15:54:37 +00:00
Rong Xu 7ea131c20c [PGO] Fix the buildbot failure in r362995
Fixed one unused variable warning.

llvm-svn: 363004
2019-06-10 23:20:04 +00:00
Rong Xu e44fa83c37 [PGO] Handle cases of non-instrument BBs
As shown in PR41279, some basic blocks (such as catchswitch) cannot be
instrumented. This patch filters out these BBs in PGO instrumentation.
It also sets the profile count to the fail-to-instrument edge, so that we
can propagate the counts in the CFG.

Differential Revision: https://reviews.llvm.org/D62700

llvm-svn: 362995
2019-06-10 22:36:27 +00:00
Rong Xu e88173abc0 [PGO] Handle cases of failing to split critical edges
Fix PR41279 where critical edges to EHPad are not split.
The fix is to not instrument those critical edges. We used to be able to know
the size of counters right after MST is computed. With this, we have to
pre-collect the instrument BBs to know the size, and then instrument them.

Differential Revision: https://reviews.llvm.org/D62439

llvm-svn: 361882
2019-05-28 21:45:56 +00:00
Dmitry Mikulin 312b5f86b7 The error message for mismatched value sites is very cryptic.
Make it more readable for an average user.

Differential Revision: https://reviews.llvm.org/D60896

llvm-svn: 359043
2019-04-23 22:26:55 +00:00
Rong Xu 959ef16859 [PGO] Better handling of profile hash mismatch
We currently assume profile hash conflicts will be caught by an upfront
check and we assert for the cases that escape the check. The assumption
is not always true as there are chances of conflict. This patch prints
a warning and skips annotating the function for the escaped cases,.

Differential Revision: https://reviews.llvm.org/D60154

llvm-svn: 358225
2019-04-11 20:54:17 +00:00
Fangrui Song 2c5c12c041 Change some dyn_cast to more apropriate isa. NFC
llvm-svn: 357773
2019-04-05 16:16:23 +00:00
Jordan Rupprecht 090683b85e [NFC] Fix PGO link error in shared libs build
llvm-svn: 355346
2019-03-04 22:54:44 +00:00
Rong Xu a6ff69f6dd [PGO] Context sensitive PGO (part 2)
Part 2 of CSPGO changes (mostly related to ProfileSummary).
Note that I use a default parameter in setProfileSummary() and getSummary().
This is to break the dependency in clang. I will make the parameter explicit
after changing clang in a separated patch.

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

llvm-svn: 355131
2019-02-28 19:55:07 +00:00
Rong Xu 6cdf3d8086 Recommit r354930 "[PGO] Context sensitive PGO (part 1)"
Fixed UBSan failures.

llvm-svn: 355005
2019-02-27 17:24:33 +00:00
Vlad Tsyrklevich c01643087e Revert "[PGO] Context sensitive PGO (part 1)"
This reverts commit r354930, it was causing UBSan failures.

llvm-svn: 354953
2019-02-27 03:45:28 +00:00
Rong Xu 35d2d51369 [PGO] Context sensitive PGO (part 1)
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
profiles can greatly affect some downstream optimizations, in particular for
the 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.

A typical usage:
// 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

This change touches many components in the compiler. The reviewed patch
(D54175) will committed in phrases.

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

llvm-svn: 354930
2019-02-26 22:37:46 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

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

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

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Chandler Carruth 57578aaf96 [CallSite removal] Port `IndirectCallSiteVisitor` to use `CallBase` and
update client code.

Also rename it to use the more generic term `call` instead of something
that could be confused with a praticular type.

Differential Revision: https://reviews.llvm.org/D56183

llvm-svn: 350508
2019-01-07 07:15:51 +00:00
Rong Xu fb4bcc452c [PGO] Exit early if all count values are zero
If all the edge counts for a function are zero, skip count population and
annotation, as nothing will happen. This can save some compile time.

Differential Revision: https://reviews.llvm.org/D54212

llvm-svn: 346370
2018-11-07 23:51:20 +00:00
Chandler Carruth edb12a838a [TI removal] Make variables declared as `TerminatorInst` and initialized
by `getTerminator()` calls instead be declared as `Instruction`.

This is the biggest remaining chunk of the usage of `getTerminator()`
that insists on the narrow type and so is an easy batch of updates.
Several files saw more extensive updates where this would cascade to
requiring API updates within the file to use `Instruction` instead of
`TerminatorInst`. All of these were trivial in nature (pervasively using
`Instruction` instead just worked).

llvm-svn: 344502
2018-10-15 10:04:59 +00:00
Richard Smith 6c67662816 Add a flag to remap manglings when reading profile data information.
This can be used to preserve profiling information across codebase
changes that have widespread impact on mangled names, but across which
most profiling data should still be usable. For example, when switching
from libstdc++ to libc++, or from the old libstdc++ ABI to the new ABI,
or even from a 32-bit to a 64-bit build.

The user can provide a remapping file specifying parts of mangled names
that should be treated as equivalent (eg, std::__1 should be treated as
equivalent to std::__cxx11), and profile data will be treated as
applying to a particular function if its name is equivalent to the name
of a function in the profile data under the provided equivalences. See
the documentation change for a description of how this is configured.

Remapping is supported for both sample-based profiling and instruction
profiling. We do not support remapping indirect branch target
information, but all other profile data should be remapped
appropriately.

Support is only added for the new pass manager. If someone wants to also
add support for this for the old pass manager, doing so should be
straightforward.

This is the LLVM side of Clang r344199.

Reviewers: davidxl, tejohnson, dlj, erik.pilkington

Subscribers: mehdi_amini, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D51249

llvm-svn: 344200
2018-10-10 23:13:47 +00:00
Nicola Zaghen d34e60ca85 Rename DEBUG macro to LLVM_DEBUG.
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
2018-05-14 12:53:11 +00:00
Adrian Prantl 5f8f34e459 Remove \brief commands from doxygen comments.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
2018-05-01 15:54:18 +00:00
Hiroshi Inoue ae17900997 [NFC] fix trivial typos in document and comments
"not not" -> "not" etc

llvm-svn: 330083
2018-04-14 08:59:00 +00:00
Rong Xu 662f38b16f [PGO] Fix branch probability remarks assert
Fixed counter/weight overflow that leads to an assertion. Also fixed the help
string for pgo-emit-branch-prob option.

Differential Revision: https://reviews.llvm.org/D44809

llvm-svn: 328653
2018-03-27 18:55:56 +00:00
David Blaikie 4fe1fe1418 Fix Layering, move instrumentation transform headers into Instrumentation subdirectory
llvm-svn: 328379
2018-03-23 22:11:06 +00:00
Easwaran Raman e5b8de2f1f Add a ProfileCount class to represent entry counts.
Summary:
The class wraps a uint64_t and an enum to represent the type of profile
count (real and synthetic) with some helper methods.

Reviewers: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41883

llvm-svn: 322771
2018-01-17 22:24:23 +00:00
Hiroshi Yamauchi f3bda1daa2 Split IndirectBr critical edges before PGO gen/use passes.
Summary:
The PGO gen/use passes currently fail with an assert failure if there's a
critical edge whose source is an IndirectBr instruction and that edge
needs to be instrumented.

To avoid this in certain cases, split IndirectBr critical edges in the PGO
gen/use passes. This works for blocks with single indirectbr predecessors,
but not for those with multiple indirectbr predecessors (splitting an
IndirectBr critical edge isn't always possible.)

Reviewers: davidxl, xur

Reviewed By: davidxl

Subscribers: efriedma, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D40699

llvm-svn: 320511
2017-12-12 19:07:43 +00:00
Xinliang David Li fa3f1a15b2 [PGO] change arg type to uint64_t to match member field type
llvm-svn: 320285
2017-12-10 07:39:53 +00:00
Xinliang David Li d91057bf52 Revert r320104: infinite loop profiling bug fix
Causes unexpected memory issue with New PM this time.
The new PM invalidates BPI but not BFI, leaving the
reference to BPI from BFI invalid.

Abandon this patch.  There is a more general solution
which also handles runtime infinite loop (but not statically).

llvm-svn: 320180
2017-12-08 19:38:07 +00:00
Xinliang David Li 4b0027f671 [PGO] detect infinite loop and form MST properly
Differential Revision: http://reviews.llvm.org/D40873

llvm-svn: 320104
2017-12-07 22:23:28 +00:00
Xinliang David Li 45c819063a Revert r319794: [PGO] detect infinite loop and form MST properly: memory leak problem
llvm-svn: 319841
2017-12-05 21:54:01 +00:00
Xinliang David Li cc35bc9efc [PGO] detect infinite loop and form MST properly
Differential Revision: http://reviews.llvm.org/D40702

llvm-svn: 319794
2017-12-05 17:19:41 +00:00
Hiroshi Yamauchi c94d4d70d8 Add heuristics for irreducible loop metadata under PGO
Summary:
Add the following heuristics for irreducible loop metadata:

- When an irreducible loop header is missing the loop header weight metadata,
  give it the minimum weight seen among other headers.
- Annotate indirectbr targets with the loop header weight metadata (as they are
  likely to become irreducible loop headers after indirectbr tail duplication.)

These greatly improve the accuracy of the block frequency info of the Python
interpreter loop (eg. from ~3-16x off down to ~40-55% off) and the Python
performance (eg. unpack_sequence from ~50% slower to ~8% faster than GCC) due to
better register allocation under PGO.

Reviewers: davidxl

Reviewed By: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39980

llvm-svn: 318693
2017-11-20 21:03:38 +00:00
Hiroshi Yamauchi dce9def3dd Irreducible loop metadata for more accurate block frequency under PGO.
Summary:
Currently the block frequency analysis is an approximation for irreducible
loops.

The new irreducible loop metadata is used to annotate the irreducible loop
headers with their header weights based on the PGO profile (currently this is
approximated to be evenly weighted) and to help improve the accuracy of the
block frequency analysis for irreducible loops.

This patch is a basic support for this.

Reviewers: davidxl

Reviewed By: davidxl

Subscribers: mehdi_amini, llvm-commits, eraman

Differential Revision: https://reviews.llvm.org/D39028

llvm-svn: 317278
2017-11-02 22:26:51 +00:00
Eugene Zelenko fce435764e [Transforms] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
llvm-svn: 316253
2017-10-21 00:57:46 +00:00
Vivek Pandya 9590658fb8 [NFC] Convert OptimizationRemarkEmitter old emit() calls to new closure
parameterized emit() calls

Summary: This is not functional change to adopt new emit() API added in r313691.

Reviewed By: anemet

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38285

llvm-svn: 315476
2017-10-11 17:12:59 +00:00
Adam Nemet 0965da2055 Rename OptimizationDiagnosticInfo.* to OptimizationRemarkEmitter.*
Sync it up with the name of the class actually defined here.  This has been
bothering me for a while...

llvm-svn: 315249
2017-10-09 23:19:02 +00:00
Hiroshi Yamauchi a43913cfaf Add options to dump PGO counts in text.
Summary:
Added text options to -pgo-view-counts and -pgo-view-raw-counts that dump block frequency and branch probability info in text.

This is useful when the graph is very large and complex (the dot command crashes, lines/edges too close to tell apart, hard to navigate without textual search) or simply when text is preferred.

Reviewers: davidxl

Reviewed By: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D37776

llvm-svn: 313159
2017-09-13 17:20:38 +00:00
Rong Xu 15848e5977 [PGO] Set edge weights for indirectbr instruction with profile counts
Current PGO only annotates the edge weight for branch and switch instructions
with profile counts. We should also annotate the indirectbr instruction as
all the information is there. This patch enables the annotating for indirectbr
instructions. Also uses this annotation in branch probability analysis.

Differential Revision: https://reviews.llvm.org/D37074

llvm-svn: 311604
2017-08-23 21:36:02 +00:00
Xinliang David Li 8e43698cf1 [PGOInstr] Add a debug print
llvm-svn: 308785
2017-07-21 21:36:25 +00:00
Davide Italiano 0c8d26c312 [PGO] Move the PGOInstrumentation pass to new OptRemark API.
This fixes PR33791.

llvm-svn: 308668
2017-07-20 20:43:05 +00:00
Craig Topper 79ab643da8 [Constants] If we already have a ConstantInt*, prefer to use isZero/isOne/isMinusOne instead of isNullValue/isOneValue/isAllOnesValue inherited from Constant. NFCI
Going through the Constant methods requires redetermining that the Constant is a ConstantInt and then calling isZero/isOne/isMinusOne.

llvm-svn: 307292
2017-07-06 18:39:47 +00:00
Ana Pazos f731bde064 [PATCH] [PGO] Fixed cast operation in emIntrinsicVisitor::instrumentOneMemIntrinsic.
Reviewers: xur, efriedma, davidxl

Reviewed By: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34293

llvm-svn: 305737
2017-06-19 20:04:33 +00:00
Xinliang David Li 0a0acbcf78 [PartialInlining] Emit branch info and profile data as remarks
This allows us to collect profile statistics to tune static 
branch prediction.

Differential Revision: http://reviews.llvm.org/D33746

llvm-svn: 304452
2017-06-01 18:58:50 +00:00
Teresa Johnson cd2aa0d2e4 Fix a couple of typos in memory intrinsic optimization output (NFC)
s/instrinsic/intrinsic

llvm-svn: 303782
2017-05-24 17:55:25 +00:00
Rong Xu 48596b6f7a [PGO] Memory intrinsic calls optimization based on profiled size
This patch optimizes two memory intrinsic operations: memset and memcpy based
on the profiled size of the operation. The high level transformation is like:
  mem_op(..., size)
  ==>
  switch (size) {
    case s1:
       mem_op(..., s1);
       goto merge_bb;
    case s2:
       mem_op(..., s2);
       goto merge_bb;
    ...
    default:
       mem_op(..., size);
       goto merge_bb;
    }
  merge_bb:

Differential Revision: http://reviews.llvm.org/D28966

llvm-svn: 299446
2017-04-04 16:42:20 +00:00
Rong Xu 8e06e80b87 [PGO] Change the internal options description. nfc.
llvm-svn: 298120
2017-03-17 20:51:44 +00:00
Rong Xu e60343d6b0 [PGO] Value profile for size of memory intrinsic calls
This patch annotates the valuesites profile to memory intrinsics.

Differential Revision: http://reviews.llvm.org/D31002

llvm-svn: 298110
2017-03-17 18:07:26 +00:00
Rong Xu 60faea19f8 Resubmit r297897: [PGO] Value profile for size of memory intrinsic calls
R297897 inadvertently enabled annotation for memop profiling. This new patch
fixed it.

llvm-svn: 297996
2017-03-16 21:15:48 +00:00
Eric Liu 971de62291 Revert "[PGO] Value profile for size of memory intrinsic calls"
This commit reverts r297897 and r297909.

llvm-svn: 297951
2017-03-16 13:16:35 +00:00
Vitaly Buka ca6ecd213a Revert "Revert "[PGO] Minor cleanup for count instruction in SelectInstVisitor.""
Previously reverted wrong revision.

This reverts commit r297910.

llvm-svn: 297911
2017-03-15 23:07:41 +00:00
Vitaly Buka de85ad895d Revert "[PGO] Minor cleanup for count instruction in SelectInstVisitor."
Fails LLVMFuzzer.LLVMFuzzer.value-profile-strncmp.test

This reverts commit r297892.

llvm-svn: 297910
2017-03-15 23:06:22 +00:00
Rong Xu 4ed52798ce [PGO] Value profile for size of memory intrinsic calls
This patch adds the value profile support to profile the size parameter of
memory intrinsic calls: memcpy, memcmp, and memmov.

Differential Revision: http://reviews.llvm.org/D28965

llvm-svn: 297897
2017-03-15 21:47:27 +00:00
Rong Xu d709b0fe95 [PGO] Minor cleanup for count instruction in SelectInstVisitor.
Summary:
NSIs can be double-counted by different operations in
SelectInstVisitor. Sink the the update to VM_counting mode only.
Also reset the value for each counting operation.

Reviewers: davidxl

Reviewed By: davidxl

Subscribers: xur, llvm-commits

Differential Revision: https://reviews.llvm.org/D30999

llvm-svn: 297892
2017-03-15 21:05:24 +00:00