[ICP] Add a few tunings to indirect-call-promtion
Indirect-call promotion (ICP) has been adjusted with the following
tunings:
(1) Candidate functions can be now ICP'd even if only a declaration is
present.
(2) All non-cold candidate functions are now considered by ICP.
Previously, only hot targets were considered.
(3) If one target cannot be ICP'd, proceed with the remaining targets
instead of exiting the callsite.
This update hides all tunings under internal options and disables them
by default. They'll be enabled in a later update. There'll also be
another update to address the "not found" issue with indirect targets.
## Purpose
This patch is one in a series of code-mods that annotate LLVM’s public
interface for export. This patch annotates the `llvm/Analysis` library.
These annotations currently have no meaningful impact on the LLVM build;
however, they are a prerequisite to support an LLVM Windows DLL (shared
library) build.
## Background
This effort is tracked in #109483. Additional context is provided in
[this
discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307),
and documentation for `LLVM_ABI` and related annotations is found in the
LLVM repo
[here](https://github.com/llvm/llvm-project/blob/main/llvm/docs/InterfaceExportAnnotations.rst).
The bulk of these changes were generated automatically using the
[Interface Definition Scanner (IDS)](https://github.com/compnerd/ids)
tool, followed formatting with `git clang-format`.
The following manual adjustments were also applied after running IDS on
Linux:
- Add `#include "llvm/Support/Compiler.h"` to files where it was not
auto-added by IDS due to no pre-existing block of include statements.
- Add `LLVM_TEMPLATE_ABI` and `LLVM_EXPORT_TEMPLATE` to exported
instantiated templates
- Add `LLVM_ABI` to a subset of private class methods and fields that
require export
- Add `LLVM_ABI` to a small number of symbols that require export but
are not declared in headers
## Validation
Local builds and tests to validate cross-platform compatibility. This
included llvm, clang, and lldb on the following configurations:
- Windows with MSVC
- Windows with Clang
- Linux with GCC
- Linux with Clang
- Darwin with Clang
Flatten the profile pre-thinlink so that ThinLTO has something to work with for the parts of the binary that aren't covered by contextual profiles. Post-thinlink, the flattener is re-run and will actually change profile info, but just for the modules containing contextual trees ("specialized modules"). For the rest, the flattener just yanks out the instrumentation.
This will make it possible to add visibility attributes to these
variables. This also fixes some type mismatches between the
declaration and the definition.
Reviewed By: bogner, huangjd
Differential Revision: https://reviews.llvm.org/D156599
Currently, to use PSI->isFunctionHotInCallGraph, we first need to
calculate BPI->BFI, which is expensive. Instead, we can implement this
directly with MBFI. Also as @wenlei mentioned in another patch review,
that MachineSizeOpts already has isFunctionColdInCallGraph,
isFunctionHotInCallGraphNthPercentile, etc implemented. These can be
refactored and so they can be reused across MachineFunctionSplitting
and MachineSizeOpts passes.
This CL does this - it refactors out those internal static functions
into PSI as templated functions, so they can be accessed easily.
Differential Revision: https://reviews.llvm.org/D153927
This reverts commit 4d8cf2ae6804e0d3f2b668dbec0f5c1983358328.
There is a library layering violation. LLVMAnalysis cannot depend on LLVMCodeGen.
```
llvm/include/llvm/Analysis/ProfileSummaryInfo.h:19:10: fatal error: 'llvm/CodeGen/MachineFunction.h' file not found
19 | #include "llvm/CodeGen/MachineFunction.h"
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
In D152399, we calculate BPI->BFI in MachineFunctionSplit pass just to
use PSI->isFunctionHotInCallGraph, which is expensive. Instead, we can
implement this directly with MBFI.
Reviewer mentioned in the comment, that machine_size_opts already has
isFunctionColdInCallGraph, isFunctionHotInCallGraphNthPercentile, etc
implemented. These can be refactored and reused across MFS and machine
size opts.
This CL does this - it refactors out those internal static functions
into PSI as templated functions, so they can be accessed easily.
Differential Revision: https://reviews.llvm.org/D153927
In D152399, we calculate BPI->BFI in MachineFunctionSplit pass just to
use PSI->isFunctionHotInCallGraph, which is expensive. Instead, we can
implement this directly with MBFI.
Reviewer mentioned in the comment, that machine_size_opts already has
isFunctionColdInCallGraph, isFunctionHotInCallGraphNthPercentile, etc
implemented. These can be refactored and reused across MFS and machine
size opts.
This CL does this - it refactors out those internal static functions
into PSI as templated functions, so they can be accessed easily.
Differential Revision: https://reviews.llvm.org/D152758
This reverts commit aae8524bcc26cf04729f2bbc02ecb54233a587e4, which was
found to cause a few unexpected benchmark performance differences that
need investigation.
As pointed out in
https://discourse.llvm.org/t/undeterministic-thin-index-file/69985, the
block count added to distributed ThinLTO index files breaks incremental
builds on ThinLTO - if any linked file has a different number of BBs,
then the accumulated sum placed in the index files will change, causing
all ThinLTO backend compiles to be redone.
This was only used for partial sample profiles, and was therefore
removed for other cases (3adc6e03080c6d38a51f5c5b6744b7c0d9c7541b).
Subsequent testing did not show a performance effect of disabling this
feature even for partial sample profiles. Therefore, switch the default
to false. If this does not cause a noticeable performance degradation
after the default flip, we can remove this support completely.
Differential Revision: https://reviews.llvm.org/D151249
value() has undesired exception checking semantics and calls
__throw_bad_optional_access in libc++. Moreover, the API is unavailable without
_LIBCPP_NO_EXCEPTIONS on older Mach-O platforms (see
_LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS).
This commit fixes LLVMAnalysis and its dependencies.
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
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
The change adds support for triming and merging cold context when mergine CSSPGO profiles using llvm-profdata. This is similar to the context profile trimming in llvm-profgen, however the flexibility to trim cold context after profile is generated can be useful.
Differential Revision: https://reviews.llvm.org/D100528
Switch to use cold threshold from profile summary for cold context merging and trimming, instead of relying on hard coded values. Minor refactoring included for switch names, etc.
Differential Revision: https://reviews.llvm.org/D98921
Change file static function getEntryForPercentile to be a static member function
in ProfileSummaryBuilder so it can be used by other files.
Differential Revision: https://reviews.llvm.org/D83439
Summary:
The working set size heuristics (ProfileSummaryInfo::hasHugeWorkingSetSize)
under the partial sample PGO may not be accurate because the profile is partial
and the number of hot profile counters in the ProfileSummary may not reflect the
actual working set size of the program being compiled.
To improve this, the (approximated) ratio of the the number of profile counters
of the program being compiled to the number of profile counters in the partial
sample profile is computed (which is called the partial profile ratio) and the
working set size of the profile is scaled by this ratio to reflect the working
set size of the program being compiled and used for the working set size
heuristics.
The partial profile ratio is approximated based on the number of the basic
blocks in the program and the NumCounts field in the ProfileSummary and computed
through the thin LTO indexing. This means that there is the limitation that the
scaled working set size is available to the thin LTO post link passes only.
Reviewers: davidxl
Subscribers: mgorny, eraman, hiraditya, steven_wu, dexonsmith, arphaman, dang, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79831
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.
them in a special text section.
For sampleFDO, because the optimized build uses profile generated from
previous release, previously we couldn't tell a function without profile
was truely cold or just newly created so we had to treat them conservatively
and put them in .text section instead of .text.unlikely. The result was when
we persuing the best performance by locking .text.hot and .text in memory,
we wasted a lot of memory to keep cold functions inside.
In https://reviews.llvm.org/D66374, we introduced profile symbol list to
discriminate functions being cold versus functions being newly added.
This mechanism works quite well for regular use cases in AutoFDO. However,
in some case, we can only have a partial profile when optimizing a target.
The partial profile may be an aggregated profile collected from many targets.
The profile symbol list method used for regular sampleFDO profile is not
applicable to partial profile use case because it may be too large and
introduce many false positives.
To solve the problem for partial profile use case, we provide an option called
--profile-unknown-in-special-section. For functions without profile, we will
still treat them conservatively in compiler optimizations -- for example,
treat them as warm instead of cold in inliner. When we use profile info to
add section prefix for functions, we will discriminate functions known to be
not cold versus functions without profile (being unknown), and we will put
functions being unknown in a special text section called .text.unknown.
Runtime system will have the flexibility to decide where to put the special
section in order to achieve a balance between performance and memory saving.
Differential Revision: https://reviews.llvm.org/D62540
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
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
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
ProfileSampleAccurate is used to indicate the profile has exact match to the
code to be optimized.
Previously ProfileSampleAccurate is handled in ProfileSummaryInfo::isColdCallSite
and ProfileSummaryInfo::isColdBlock. A better solution is to initialize function
entry count to 0 when ProfileSampleAccurate is true, so we don't have to handle
ProfileSampleAccurate in multiple places.
Differential Revision: https://reviews.llvm.org/D55660
llvm-svn: 349088
For SampleFDO, when a callsite doesn't appear in the profile, it will not be marked as cold callsite unless the option -profile-sample-accurate is specified.
But profile-sample-accurate doesn't cover function isFunctionColdInCallGraph which is used to decide whether a function should be put into text.unlikely section, so even if the user knows the profile is accurate and specifies profile-sample-accurate, those functions not appearing in the sample profile are still not be put into text.unlikely section right now.
The patch fixes that.
Differential Revision: https://reviews.llvm.org/D55567
llvm-svn: 348940
