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Commit Graph

55 Commits

Author SHA1 Message Date
Daniel Sanders
3239c724ab [debugify] Move the Debugify pass from tools/opt to lib/Transform/Utils
Summary:
I need to make use of this pass from a driver program that isn't opt.
Therefore this patch moves this pass into the LLVM library so that it is
available for use elsewhere.

There was one function I kept in tools/opt which is exportDebugifyStats()
this is because it's serializing the statistics into a human readable
format and this seemed more in keeping with opt than a library function

Reviewers: vsk, aprantl

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69926
2019-11-07 14:41:54 -08:00
Alina Sbirlea
2330568f0e [NewPassManager] Adding pass tuning options: loop vectorize.
Summary:
Trying to add the plumbing necessary to add tuning options to the new pass manager.
Testing with the flags for loop vectorize.

Reviewers: chandlerc

Subscribers: sanjoy, mehdi_amini, jlebar, steven_wu, dexonsmith, dang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59723

llvm-svn: 358763
2019-04-19 16:11:59 +00:00
Rong Xu
888aa59db9 [PGO] Context sensitive PGO (part 3)
Part 3 of CSPGO changes (mostly related to PassMananger).

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

llvm-svn: 355330
2019-03-04 20:21:27 +00:00
Chandler Carruth
ae65e281f3 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
Wei Mi
c317b3b823 [PGO] Make pgo related options in opt more consistent.
Currently we have pgo options defined in PassManagerBuilder.cpp only for
instrument pgo, but not for sample pgo. We also have pgo options defined
in NewPMDriver.cpp in opt only for new pass manager and for all kinds of
pgo. They have some inconsistency.

To make the options more consistent and make tests writing easier, the
patch let old pass manager to share the same pgo options with new pass
manager in opt, and removes the options in PassManagerBuilder.cpp.

Differential Revision: https://reviews.llvm.org/D56749

llvm-svn: 351392
2019-01-16 23:19:02 +00:00
Philip Pfaffe
26086dc538 [newpm] Fix r346645: Missing consume of the Error return by the pipeline parser
llvm-svn: 346649
2018-11-12 12:27:58 +00:00
Philip Pfaffe
2815eb046a Add an OptimizerLast EP
Summary:
It turns out that we need an OptimizerLast PassBuilder extension point
after all. I missed the relevance of this EP the first time. By legacy PM magic,
function passes added at this EP get added to the last _Function_ PM, which is a
feature we lost when dropping this EP for the new PM.

A key difference between this and the legacy PassManager's OptimizerLast
callback is that this extension point is not triggered at O0. Extensions
to the O0 pipeline should append their passes to the end of the overall
pipeline.

Differential Revision: https://reviews.llvm.org/D54374

llvm-svn: 346645
2018-11-12 11:17:07 +00:00
Fedor Sergeev
99f8b94bce [NewPM] teach -passes= to emit meaningful error messages
All the PassBuilder::parse interfaces now return descriptive StringError
instead of a plain bool. It allows to make -passes/aa-pipeline parsing
errors context-specific and thus less confusing.

TODO: ideally we should also make suggestions for misspelled pass names,
but that requires some extensions to PassBuilder.

Reviewed By: philip.pfaffe, chandlerc
Differential Revision: https://reviews.llvm.org/D53246

llvm-svn: 344685
2018-10-17 10:36:23 +00:00
Fedor Sergeev
0259ebdd6a Revert "[NewPM] teach -passes= to emit meaningful error messages"
This reverts r344519 due to failures in pipeline-parsing test.

llvm-svn: 344524
2018-10-15 15:36:08 +00:00
Fedor Sergeev
dd4337b392 [NewPM] teach -passes= to emit meaningful error messages
Summary:
All the PassBuilder::parse interfaces now return descriptive StringError
instead of a plain bool. It allows to make -passes/aa-pipeline parsing
errors context-specific and thus less confusing.

TODO: ideally we should also make suggestions for misspelled pass names,
but that requires some extensions to PassBuilder.

Reviewed By: philip.pfaffe, chandlerc
Differential Revision: https://reviews.llvm.org/D53246

llvm-svn: 344519
2018-10-15 15:00:18 +00:00
Richard Smith
4a1cdc1ae5 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
Fedor Sergeev
912a050cc8 [New PM][PassInstrumentation] IR printing support for New Pass Manager
Implementing -print-before-all/-print-after-all/-filter-print-func support
through PassInstrumentation callbacks.

- PrintIR routines implement printing callbacks.

- StandardInstrumentations class provides a central place to manage all
  the "standard" in-tree pass instrumentations. Currently it registers
  PrintIR callbacks.

Reviewers: chandlerc, paquette, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D50923

llvm-svn: 342896
2018-09-24 16:08:15 +00:00
Vedant Kumar
069adf4d6b [Debugify] Move interface definitions to a header, NFC
This is a minor cleanup in preparation for a change to export DI
statistics from -check-debugify. To do that, it would be cleaner to have
a dedicated header for the debugify interface.

llvm-svn: 337786
2018-07-24 00:41:28 +00:00
Nico Weber
fcf0230e34 IWYU for llvm-config.h in llvm, additions.
See r331124 for how I made a list of files missing the include.
I then ran this Python script:

    for f in open('filelist.txt'):
        f = f.strip()
        fl = open(f).readlines()

        found = False
        for i in xrange(len(fl)):
            p = '#include "llvm/'
            if not fl[i].startswith(p):
                continue
            if fl[i][len(p):] > 'Config':
                fl.insert(i, '#include "llvm/Config/llvm-config.h"\n')
                found = True
                break
        if not found:
            print 'not found', f
        else:
            open(f, 'w').write(''.join(fl))

and then looked through everything with `svn diff | diffstat -l | xargs -n 1000 gvim -p`
and tried to fix include ordering and whatnot.

No intended behavior change.

llvm-svn: 331184
2018-04-30 14:59:11 +00:00
Philip Pfaffe
3d76c2d6f6 Re-land r329273: [Plugins] Add a slim plugin API to work together with the new PM
Fix unittest: Do not link LLVM into the test plugin.
Additionally, remove an unrelated change that slipped in in r329273.

llvm-svn: 329293
2018-04-05 15:04:13 +00:00
Philip Pfaffe
c796c48cc8 Revert "[Plugins] Add a slim plugin API to work together with the new PM"
This reverts commit ecf3ba1ab45edb1b0fadce716a7facf50dca4fbb/r329273.

llvm-svn: 329276
2018-04-05 12:42:12 +00:00
Philip Pfaffe
d9afd01962 [Plugins] Add a slim plugin API to work together with the new PM
Summary:
Add a new plugin API. This closes the gap between pass registration and out-of-tree passes for the new PassManager.

Unlike with the existing API, interaction with a plugin is always
initiated from the tools perspective. I.e., when a plugin is loaded, it
resolves and calls a well-known symbol `llvmGetPassPluginInfo` to obtain
details about the plugin. The fundamental motivation is to get rid of as
many global constructors as possible.  The API exposed by the plugin
info is kept intentionally minimal.

Reviewers: chandlerc

Reviewed By: chandlerc

Subscribers: bollu, grosser, lksbhm, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D35258

llvm-svn: 329273
2018-04-05 11:29:37 +00:00
Vedant Kumar
477f3d1e17 [opt] Port the debugify passes to the new pass manager
llvm-svn: 325294
2018-02-15 21:14:36 +00:00
David Blaikie
07fc4b0c75 NewPM: Add an extension point for the start of the pipeline.
This applies to most pipelines except the LTO and ThinLTO backend
actions - it is for use at the beginning of the overall pipeline.

This extension point will be used to add the GCOV pass when enabled in
Clang.

llvm-svn: 323166
2018-01-23 01:25:20 +00:00
Reid Kleckner
e0df0bbd27 [Support] Rename tool_output_file to ToolOutputFile, NFC
This class isn't similar to anything from the STL, so it shouldn't use
the STL naming conventions.

llvm-svn: 314050
2017-09-23 01:03:17 +00:00
Sam Elliott
e9e58e405f Keep Optimization Remark Yaml in NewPM
Summary:
The New Pass Manager infrastructure was forgetting to keep around the optimization remark yaml file that the compiler might have been producing. This meant setting the option to '-' for stdout worked, but setting it to a filename didn't give file output (presumably it was deleted because compilation didn't explicitly keep it). This change just ensures that the file is kept if compilation succeeds.

So far I have updated one of the optimization remark output tests to add a version with the new pass manager. It is my intention for this patch to also include changes to all tests that use `-opt-remark-output=` but I wanted to get the code patch ready for review while I was making all those changes.

Fixes https://bugs.llvm.org/show_bug.cgi?id=33951

Reviewers: anemet, chandlerc

Reviewed By: anemet, chandlerc

Subscribers: javed.absar, chandlerc, fhahn, llvm-commits

Differential Revision: https://reviews.llvm.org/D36906

llvm-svn: 311271
2017-08-20 01:30:45 +00:00
Philip Pfaffe
e3fd1bdb8e [Polly][PM] Register polly passes with the opt tool for the new-pm path
Summary: When polly is linked into the tools because of the LLVM_POLLY_LINK_INTO_TOOLS option being set, we need to register its passes with the PassBuilder. Because polly is linked in, we can directly call its callback registration method, which registers the appropriate callbacks with the new PM's PassBuilder. This essentially follows exactly the way it worked with the legacy PM.

Reviewers: grosser, chandlerc, bollu

Reviewed By: grosser

Subscribers: pollydev, llvm-commits

Differential Revision: https://reviews.llvm.org/D36273

llvm-svn: 310043
2017-08-04 09:28:09 +00:00
Dehao Chen
c91f04adba Make new PM honor -fdebug-info-for-profiling
Summary: The new PM needs to invoke add-discriminator pass when building with -fdebug-info-for-profiling.

Reviewers: chandlerc, davidxl

Reviewed By: chandlerc

Subscribers: sanjoy, llvm-commits

Differential Revision: https://reviews.llvm.org/D35744

llvm-svn: 309121
2017-07-26 15:01:20 +00:00
Dehao Chen
4e6c2d132d Add test coverage for new PM PGOOpt handling.
Summary: This patch adds flags and tests to cover the PGOOpt handling logic in new PM.

Reviewers: chandlerc, davide

Reviewed By: chandlerc

Subscribers: sanjoy, llvm-commits

Differential Revision: https://reviews.llvm.org/D35807

llvm-svn: 309076
2017-07-26 02:00:43 +00:00
Philip Pfaffe
5d4ff6ec92 [PM] Another post-commit fix in NewPMDriver
There were two errors in the parsing of opt's command line options for
extension point pipelines. The EP callbacks are not supposed to return a
value. To check the pipeline text for correctness, I now try to parse it
into a temporary PM object, and print a message on failure. This solves
the compile time error for the lambda return type, as well as correctly
handles unparsable pipelines now.

llvm-svn: 307649
2017-07-11 11:17:44 +00:00
Philip Pfaffe
7309c59020 [PM] Fix a warning.
The DebugLogging argument was unused in the EP callbacks registration.

llvm-svn: 307536
2017-07-10 13:54:23 +00:00
Philip Pfaffe
4d43aef242 [PM] Fix r307532: Get rid of a dangling reference.
Escaping lambda by-reference capture of local variable caused a dangling
reference.

llvm-svn: 307534
2017-07-10 12:48:51 +00:00
Philip Pfaffe
3bb640f8fb [PM] Enable registration of out-of-tree passes with PassBuilder
Summary:
This patch adds a callback registration API to the PassBuilder,
enabling registering out-of-tree passes with it.

Through the Callback API, callers may register callbacks with the
various stages at which passes are added into pass managers, including
parsing of a pass pipeline as well as at extension points within the
default -O pipelines.

Registering utilities like `require<>` and `invalidate<>` needs to be
handled manually by the caller, but a helper is provided.

Additionally, adding passes at pipeline extension points is exposed
through the opt tool. This patch adds a `-passes-ep-X` commandline
option for every extension point X, which opt parses into pipelines
inserted into that extension point.

Reviewers: chandlerc

Reviewed By: chandlerc

Subscribers: lksbhm, grosser, davide, mehdi_amini, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D33464

llvm-svn: 307532
2017-07-10 10:57:55 +00:00
Tim Shen
7d412810b1 [ThinLTO] Migrate ThinLTOBitcodeWriter to the new PM.
Summary: Also see D33429 for other ThinLTO + New PM related changes.

Reviewers: davide, chandlerc, tejohnson

Subscribers: mehdi_amini, Prazek, cfe-commits, inglorion, llvm-commits, eraman

Differential Revision: https://reviews.llvm.org/D33525

llvm-svn: 304378
2017-06-01 01:02:12 +00:00
Chandler Carruth
e59e4b3dc5 [PM] Separate the LoopAnalysisManager from the LoopPassManager and move
the latter to the Transforms library.

While the loop PM uses an analysis to form the IR units, the current
plan is to have the PM itself establish and enforce both loop simplified
form and LCSSA. This would be a layering violation in the analysis
library.

Fundamentally, the idea behind the loop PM is to *transform* loops in
addition to running passes over them, so it really seemed like the most
natural place to sink this was into the transforms library.

We can't just move *everything* because we also have loop analyses that
rely on a subset of the invariants. So this patch splits the the loop
infrastructure into the analysis management that has to be part of the
analysis library, and the transform-aware pass manager.

This also required splitting the loop analyses' printer passes out to
the transforms library, which makes sense to me as running these will
transform the code into LCSSA in theory.

I haven't split the unittest though because testing one component
without the other seems nearly intractable.

Differential Revision: https://reviews.llvm.org/D28452

llvm-svn: 291662
2017-01-11 09:43:56 +00:00
Davide Italiano
e6628836b6 [opt] Remove an unused argument to runPassPipeline().
I have plans to use this API also in libLTO (and maybe lld).

llvm-svn: 280770
2016-09-07 00:48:47 +00:00
Teresa Johnson
3e48c70c20 [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
Davide Italiano
e4bb443f4f [PM] Refactor cross-registration of AM into an helper.
Requested by: Chandler Carruth.

llvm-svn: 269582
2016-05-14 23:21:50 +00:00
Chandler Carruth
6150530377 [PM] Make the AnalysisManager parameter to run methods a reference.
This was originally a pointer to support pass managers which didn't use
AnalysisManagers. However, that doesn't realistically come up much and
the complexity of supporting it doesn't really make sense.

In fact, *many* parts of the pass manager were just assuming the pointer
was never null already. This at least makes it much more explicit and
clear.

llvm-svn: 263219
2016-03-11 11:05:24 +00:00
Justin Bogner
5af532d89d PM: Implement a basic loop pass manager
This creates the new-style LoopPassManager and wires it up with dummy
and print passes.

This version doesn't support modifying the loop nest at all. It will
be far easier to discuss and evaluate the approaches to that with this
in place so that the boilerplate is out of the way.

llvm-svn: 261831
2016-02-25 07:23:08 +00:00
Chandler Carruth
a482d2bc0a [PM/AA] Teach the new pass manager to use pass-by-lambda for registering
analysis passes, support pre-registering analyses, and use that to
implement parsing and pre-registering a custom alias analysis pipeline.

With this its possible to configure the particular alias analysis
pipeline used by the AAManager from the commandline of opt. I've updated
the test to show this effectively in use to build a pipeline including
basic-aa as part of it.

My big question for reviewers are around the APIs that are used to
expose this functionality. Are folks happy with pass-by-lambda to do
pass registration? Are folks happy with pre-registering analyses as
a way to inject customized instances of an analysis while still using
the registry for the general case?

Other thoughts of course welcome. The next round of patches will be to
add the rest of the alias analyses into the new pass manager and wire
them up here so that they can be used from opt. This will require
extending the (somewhate limited) functionality of AAManager w.r.t.
module passes.

Differential Revision: http://reviews.llvm.org/D17259

llvm-svn: 261197
2016-02-18 09:45:17 +00:00
Duncan P. N. Exon Smith
8141c202b6 uselistorder: Pull the bit through PrintModulePass
Now the callers of `PrintModulePass()` (etc.) that care about use-list
order in assembly pass in the flag.

llvm-svn: 234969
2015-04-15 02:38:06 +00:00
Duncan P. N. Exon Smith
393c4f570f uselistorder: Pull bit through BitcodeWriterPass
Now the callers of `BitcodeWriterPass` decide whether or not to preserve
bitcode use-list order.

llvm-svn: 234959
2015-04-15 00:34:24 +00:00
Chandler Carruth
ef5afb1b16 [PM] Create a separate library for high-level pass management code.
This will provide the analogous replacements for the PassManagerBuilder
and other code long term. This code is extracted from the opt tool
currently, and I plan to extend it as I build up support for using the
new pass manager in Clang and other places.

Mailing this out for review in part to let folks comment on the terrible names
here. A brief word about why I chose the names I did.

The library is called "Passes" to try and make it clear that it is a high-level
utility and where *all* of the passes come together and are registered in
a common library. I didn't want it to be *limited* to a registry though, the
registry is just one component.

The class is a "PassBuilder" but this name I'm less happy with. It doesn't
build passes in any traditional sense and isn't a Builder-style API at all. The
class is a PassRegisterer or PassAdder, but neither of those really make a lot
of sense. This class is responsible for constructing passes for registry in an
analysis manager or for population of a pass pipeline. If anyone has a better
name, I would love to hear it. The other candidate I looked at was
PassRegistrar, but that doesn't really fit either. There is no register of all
the passes in use, and so I think continuing the "registry" analog outside of
the registry of pass *names* and *types* is a mistake. The objects themselves
are just objects with the new pass manager.

Differential Revision: http://reviews.llvm.org/D8054

llvm-svn: 231556
2015-03-07 09:02:36 +00:00
Chandler Carruth
4efb41707c [PM] Port TTI to the new pass manager, introducing a TargetIRAnalysis to
produce it.

This adds a function to the TargetMachine that produces this analysis
via a callback for each function. This in turn faves the way to produce
a *different* TTI per-function with the correct subtarget cached.

I've also done the necessary wiring in the opt tool to thread the target
machine down and make it available to the pass registry so that we can
construct this analysis from a target machine when available.

llvm-svn: 227721
2015-02-01 10:11:22 +00:00
Chandler Carruth
72e4fd68d8 [PM] Refactor the analysis registration and pass pipeline parsing to
live in a class.

While this isn't really significant right now, I need to expose some
state to the pass construction expressions, and making them get
evaluated within a class context is a nice way to collect members that
they may need to access.

llvm-svn: 227715
2015-02-01 07:40:05 +00:00
Chandler Carruth
354bc97f39 [PM] Port domtree to the new pass manager (at last).
This adds the domtree analysis to the new pass manager. The analysis
returns the same DominatorTree result entity used by the old pass
manager and essentially all of the code is shared. We just have
different boilerplate for running and printing the analysis.

I've converted one test to run in both modes just to make sure this is
exercised while both are live in the tree.

llvm-svn: 225969
2015-01-14 10:19:28 +00:00
Chandler Carruth
d227b42252 [PM] Push the debug option for the new pass manager into the opt tool
and expose the necessary hooks in the API directly.

This makes it much cleaner for example to log the usage of a pass
manager from a library. It also makes it more obvious that this
functionality isn't "optional" or "asserts-only" for the pass manager.

llvm-svn: 225841
2015-01-13 22:42:38 +00:00
Chandler Carruth
bfe0de7cfc [PM] Move the analysis registry into the Passes.cpp file and provide
a normal interface for it in Passes.h.

This gives us essentially a single interface for running pass managers
which are provided from the bottom of the LLVM stack through interfaces
at the top of the LLVM stack that populate them with all of the
different analyses available throughout. It also means there is a single
blob of code that needs to include all of the pass headers and needs to
deal with the registry of passes and parsing names.

No functionality changed intended, should just be cleanup.

llvm-svn: 225237
2015-01-06 02:21:37 +00:00
Chandler Carruth
2a8b1d4992 [PM] Switch the new pass manager to use a reference-based API for IR
units.

This was debated back and forth a bunch, but using references is now
clearly cleaner. Of all the code written using pointers thus far, in
only one place did it really make more sense to have a pointer. In most
cases, this just removes immediate dereferencing from the code. I think
it is much better to get errors on null IR units earlier, potentially
at compile time, than to delay it.

Most notably, the legacy pass manager uses references for its routines
and so as more and more code works with both, the use of pointers was
likely to become really annoying. I noticed this when I ported the
domtree analysis over and wrote the entire thing with references only to
have it fail to compile. =/ It seemed better to switch now than to
delay. We can, of course, revisit this is we learn that references are
really problematic in the API.

llvm-svn: 225145
2015-01-05 02:47:05 +00:00
Chandler Carruth
88dfbdf34a [PM] Add a new-PM-style CGSCC pass manager using the newly added
LazyCallGraph analysis framework. Wire it up all the way through the opt
driver and add some very basic testing that we can build pass pipelines
including these components. Still a lot more to do in terms of testing
that all of this works, but the basic pieces are here.

There is a *lot* of boiler plate here. It's something I'm going to
actively look at reducing, but I don't have any immediate ideas that
don't end up making the code terribly complex in order to fold away the
boilerplate. Until I figure out something to minimize the boilerplate,
almost all of this is based on the code for the existing pass managers,
copied and heavily adjusted to suit the needs of the CGSCC pass
management layer.

The actual CG management still has a bunch of FIXMEs in it. Notably, we
don't do *any* updating of the CG as it is potentially invalidated.
I wanted to get this in place to motivate the new analysis, and add
update APIs to the analysis and the pass management layers in concert to
make sure that the *right* APIs are present.

llvm-svn: 206745
2014-04-21 11:12:00 +00:00
Chandler Carruth
490b05fc1a [PM] Wire the analysis passes (such as they are) into the registry, and
teach the opt driver to use it rather than a manual list.

llvm-svn: 206739
2014-04-21 08:20:10 +00:00
Chandler Carruth
039285cbbf [PM] Add a new "lazy" call graph analysis pass for the new pass manager.
The primary motivation for this pass is to separate the call graph
analysis used by the new pass manager's CGSCC pass management from the
existing call graph analysis pass. That analysis pass is (somewhat
unfortunately) over-constrained by the existing CallGraphSCCPassManager
requirements. Those requirements make it *really* hard to cleanly layer
the needed functionality for the new pass manager on top of the existing
analysis.

However, there are also a bunch of things that the pass manager would
specifically benefit from doing differently from the existing call graph
analysis, and this new implementation tries to address several of them:

- Be lazy about scanning function definitions. The existing pass eagerly
  scans the entire module to build the initial graph. This new pass is
  significantly more lazy, and I plan to push this even further to
  maximize locality during CGSCC walks.
- Don't use a single synthetic node to partition functions with an
  indirect call from functions whose address is taken. This node creates
  a huge choke-point which would preclude good parallelization across
  the fanout of the SCC graph when we got to the point of looking at
  such changes to LLVM.
- Use a memory dense and lightweight representation of the call graph
  rather than value handles and tracking call instructions. This will
  require explicit update calls instead of some updates working
  transparently, but should end up being significantly more efficient.
  The explicit update calls ended up being needed in many cases for the
  existing call graph so we don't really lose anything.
- Doesn't explicitly model SCCs and thus doesn't provide an "identity"
  for an SCC which is stable across updates. This is essential for the
  new pass manager to work correctly.
- Only form the graph necessary for traversing all of the functions in
  an SCC friendly order. This is a much simpler graph structure and
  should be more memory dense. It does limit the ways in which it is
  appropriate to use this analysis. I wish I had a better name than
  "call graph". I've commented extensively this aspect.

This is still very much a WIP, in fact it is really just the initial
bits. But it is about the fourth version of the initial bits that I've
implemented with each of the others running into really frustrating
problms. This looks like it will actually work and I'd like to split the
actual complexity across commits for the sake of my reviewers. =] The
rest of the implementation along with lots of wiring will follow
somewhat more rapidly now that there is a good path forward.

Naturally, this doesn't impact any of the existing optimizer. This code
is specific to the new pass manager.

A bunch of thanks are deserved for the various folks that have helped
with the design of this, especially Nick Lewycky who actually sat with
me to go through the fundamentals of the final version here.

llvm-svn: 200903
2014-02-06 04:37:03 +00:00
Chandler Carruth
21b641366c [PM] Back out one hunk of the patch in r200901 that was *supposed* to go
in my next patch. Sorry for the breakage.

llvm-svn: 200902
2014-02-06 04:32:33 +00:00
Chandler Carruth
2250f08288 [PM] Wire up the analysis managers in the opt driver. This isn't really
necessary until we add analyses to the driver, but I have such an
analysis ready and wanted to split this out. This is actually exercised
by the existing tests of the new pass manager as the analysis managers
are cross-checked and validated by the function and module managers.

llvm-svn: 200901
2014-02-06 04:25:13 +00:00