Commit Graph

115 Commits

Author SHA1 Message Date
Teresa Johnson 897bab9b35 [ThinLTO] Record calls to aliases
Summary:
When there is a call to an alias in the same module, we were not
adding a call edge. So we could incorrectly think that the alias
was dead if it was inlined in that function, despite having a
reference imported elsewhere. This resulted in unsats at link time.

Add a call edge when the call is to an alias.

Reviewers: davide, mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25384

llvm-svn: 283664
2016-10-08 16:11:42 +00:00
Dehao Chen 5461d8bdb5 Refactor the ProfileSummaryInfo to use doInitialization and doFinalization to handle Module update.
Summary: This refactors the change in r282616

Reviewers: davidxl, eraman, mehdi_amini

Subscribers: mehdi_amini, davide, llvm-commits

Differential Revision: https://reviews.llvm.org/D25041

llvm-svn: 282630
2016-09-28 21:00:58 +00:00
Piotr Padlewski d9830eb79f [thinlto] Basic thinlto fdo heuristic
Summary:
This patch improves thinlto importer
by importing 3x larger functions that are called from hot block.

I compared performance with the trunk on spec, and there
were about 2% on povray and 3.33% on milc. These results seems
to be consistant and match the results Teresa got with her simple
heuristic. Some benchmarks got slower but I think they are just
noisy (mcf, xalancbmki, omnetpp)- running the benchmarks again with
more iterations to confirm. Geomean of all benchmarks including the noisy ones
were about +0.02%.

I see much better improvement on google branch with Easwaran patch
for pgo callsite inlining (the inliner actually inline those big functions)
Over all I see +0.5% improvement, and I get +8.65% on povray.
So I guess we will see much bigger change when Easwaran patch will land
(it depends on new pass manager), but it is still worth putting this to trunk
before it.

Implementation details changes:
- Removed CallsiteCount.
- ProfileCount got replaced by Hotness
- hot-import-multiplier is set to 3.0 for now,
didn't have time to tune it up, but I see that we get most of the interesting
functions with 3, so there is no much performance difference with higher, and
binary size doesn't grow as much as with 10.0.

Reviewers: eraman, mehdi_amini, tejohnson

Subscribers: mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D24638

llvm-svn: 282437
2016-09-26 20:37:32 +00:00
Piotr Padlewski 442d38c0b4 NFC: add early exit in ModuleSummaryAnalysis
Summary:
Changed this code because it was not very readable.
The one question that I got after changing it is, should we
count calls to intrinsics? We don't add them to caller summary,
so maybe we shouldn't also count them?

Reviewers: tejohnson, eraman, mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D23949

llvm-svn: 280036
2016-08-30 00:46:26 +00:00
Chandler Carruth b7be5b6479 [PM] Rework the new PM support for building the ModuleSummaryIndex to
directly produce the index as the value type result.

This requires making the index movable which is straightforward. It
greatly simplifies things by allowing us to completely avoid the builder
API and the layers of abstraction inherent there. Instead both pass
managers can directly construct these when run by value. They still
won't be constructed truly eagerly thanks to the optional in the legacy
PM. The code that directly builds the index can also just share a direct
function.

A notable change here is that the result type of the analysis for the
new PM is no longer a reference type. This was really problematic when
making changes to how we handle result types to make our interface
requirements *much* more strict and precise. But I think this is an
overall improvement.

Differential Revision: https://reviews.llvm.org/D23701

llvm-svn: 279216
2016-08-19 07:49:19 +00:00
Teresa Johnson f93b246f8b [PM] Port ModuleSummaryIndex analysis to new pass manager
Summary:
Port the ModuleSummaryAnalysisWrapperPass to the new pass manager.
Use it in the ported BitcodeWriterPass (similar to how we use the
legacy ModuleSummaryAnalysisWrapperPass in the legacy WriteBitcodePass).

Also, pass the -module-summary opt flag through to the new pass
manager pipeline and through to the bitcode writer pass, and add
a test that uses it.

Reviewers: mehdi_amini

Subscribers: llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D23439

llvm-svn: 278508
2016-08-12 13:53:02 +00:00
David Majnemer 0a16c22846 Use range algorithms instead of unpacking begin/end
No functionality change is intended.

llvm-svn: 278417
2016-08-11 21:15:00 +00:00
Teresa Johnson cd21a646f6 [ThinLTO] Perform profile-guided indirect call promotion
Summary:
To enable profile-guided indirect call promotion in ThinLTO mode, we
simply add call graph edges for each profitable target from the profile
to the summaries, then the summary-guided importing will consider the
callee for importing as usual.

Also we need to enable the indirect call promotion pass creation in the
PassManagerBuilder when PerformThinLTO=true (we are in the ThinLTO
backend), so that the newly imported functions are considered for
promotion in the backends.

The IC promotion profiles refer to callees by GUID, which required
adding GUIDs to the per-module VST in bitcode (and assigning them
valueIds similar to how they are assigned valueIds in the combined
index).

Reviewers: mehdi_amini, xur

Subscribers: mehdi_amini, davidxl, llvm-commits

Differential Revision: http://reviews.llvm.org/D21932

llvm-svn: 275707
2016-07-17 14:47:01 +00:00
Benjamin Kramer aa2091505f Apply clang-tidy's modernize-loop-convert to lib/Analysis.
Only minor manual fixes. No functionality change intended.

llvm-svn: 273816
2016-06-26 17:27:42 +00:00
Mehdi Amini 3b132e34b0 ThinLTO: fix assertion and refactor check for hidden use from inline ASM in a helper function
This test was crashing, and currently it breaks bootstrapping clang with debuginfo

Differential Revision: http://reviews.llvm.org/D20008

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 268715
2016-05-06 08:25:33 +00:00
Teresa Johnson df5ef8711f [ThinLTO] Refine fix to avoid renaming of uses in inline assembly.
Summary:
Refine the workaround from r266877 that attempts to prevent
renaming of locals in inline assembly, so that in addition to looking
for a llvm.used local value, that there is at least one inline assembly
call in the module. Otherwise, debug functions added to the llvm.used
can block importing/exporting unnecessarily.

Reviewers: joker.eph

Subscribers: llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D19573

llvm-svn: 267717
2016-04-27 14:19:38 +00:00
Teresa Johnson 28e457bccd [ThinLTO] Remove GlobalValueInfo class from index
Summary:
Remove the GlobalValueInfo and change the ModuleSummaryIndex to directly
reference summary objects. The info structure was there to support lazy
parsing of the combined index summary objects, which is no longer
needed and not supported.

Reviewers: joker.eph

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D19462

llvm-svn: 267344
2016-04-24 14:57:11 +00:00
Mehdi Amini c3ed48c1bd Reorganize GlobalValueSummary with a "Flags" bitfield.
Right now it only contains the LinkageType, but will be extended
with "hasSection", "isOptSize", "hasInlineAssembly", etc.

Differential Revision: http://reviews.llvm.org/D19404

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267319
2016-04-24 03:18:18 +00:00
Teresa Johnson b35cc691ea [ThinLTO] Prevent importing of "llvm.used" values
Summary:
This patch prevents importing from (and therefore exporting from) any
module with a "llvm.used" local value. Local values need to be promoted
and renamed when importing, and their presense on the llvm.used variable
indicates that there are opaque uses that won't see the rename. One such
example is a use in inline assembly.

See also the discussion at:
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098047.html

As part of this, move collectUsedGlobalVariables out of Transforms/Utils
and into IR/Module so that it can be used more widely. There are several
other places in LLVM that used copies of this code that can be cleaned
up as a follow on NFC patch.

Reviewers: joker.eph

Subscribers: pcc, llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D18986

llvm-svn: 266877
2016-04-20 14:39:45 +00:00
Teresa Johnson 2d5487cf44 [ThinLTO] Move summary computation from BitcodeWriter to new pass
Summary:
This is the first step in also serializing the index out to LLVM
assembly.

The per-module summary written to bitcode is moved out of the bitcode
writer and to a new analysis pass (ModuleSummaryIndexWrapperPass).
The pass itself uses a new builder class to compute index, and the
builder class is used directly in places where we don't have a pass
manager (e.g. llvm-as).

Because we are computing summaries outside of the bitcode writer, we no
longer can use value ids created by the bitcode writer's
ValueEnumerator. This required changing the reference graph edge type
to use a new ValueInfo class holding a union between a GUID (combined
index) and Value* (permodule index). The Value* are converted to the
appropriate value ID during bitcode writing.

Also, this enables removal of the BitWriter library's dependence on the
Analysis library that was previously required for the summary computation.

Reviewers: joker.eph

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D18763

llvm-svn: 265941
2016-04-11 13:58:45 +00:00