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268 Commits

Author SHA1 Message Date
Chandler Carruth
176c94be9c [PM] Introduce a devirtualization iteration layer for the new PM.
This is an orthogonal and separated layer instead of being embedded
inside the pass manager. While it adds a small amount of complexity, it
is fairly minimal and the composability and control seems worth the
cost.

The logic for this ends up being nicely isolated and targeted. It should
be easy to experiment with different iteration strategies wrapped around
the CGSCC bottom-up walk using this kind of facility.

The mechanism used to track devirtualization is the simplest one I came
up with. I think it handles most of the cases the existing iteration
machinery handles, but I haven't done a *very* in depth analysis. It
does however match the basic intended semantics, and we can tweak or
tune its exact behavior incrementally as necessary. One thing that we
may want to revisit is freshly building the value handle set on each
iteration. While I don't think this will be a significant cost (it is
strictly fewer value handles but more churn of value handes than the old
call graph), it is conceivable that we'll want a somewhat more clever
tracking mechanism. My hope is to layer that on as a follow up patch
with data supporting any implementation complexity it adds.

This code also provides for a basic count heuristic: if the number of
indirect calls decreases and the number of direct calls increases for
a given function in the SCC, we assume devirtualization is responsible.
This matches the heuristics currently used in the legacy pass manager.

Differential Revision: https://reviews.llvm.org/D23114

llvm-svn: 290665
2016-12-28 11:07:33 +00:00
Chandler Carruth
870a2669f0 [PM] Actually commit the test update that was supposed to accompany
r290644. Sorry for this.

llvm-svn: 290646
2016-12-28 02:31:24 +00:00
Chandler Carruth
b6ef94fb75 [PM] Teach BasicAA how to invalidate its result object.
This requires custom handling because BasicAA caches handles to other
analyses and so it needs to trigger indirect invalidation.

This fixes one of the common crashes when using the new PM in real
pipelines. I've also tweaked a regression test to check that we are at
least handling the most immediate case.

I'm going to work at re-structuring this test some to both scale better
(rather than all being in one file) and check more invalidation paths in
a follow-up commit, but I wanted to get the basic bug fix in place.

llvm-svn: 290603
2016-12-27 10:30:45 +00:00
Chandler Carruth
f3883975e2 [PM] Disable more of the loop passes -- LCSSA and LoopSimplify are also
not really wired into the loop pass manager in a way that will let us
productively use these passes yet.

This lets the new PM get farther in basic testing which is useful for
establishing a good baseline of "doesn't explode". There are still
plenty of crashers in basic testing though, this just gets rid of some
noise that is well understood and not representing a specific or narrow
bug.

llvm-svn: 290601
2016-12-27 10:16:46 +00:00
Chandler Carruth
8724378ec0 [PM] Teach the AAManager and AAResults layer (the worst offender for
inter-analysis dependencies) to use the new invalidation infrastructure.

This teaches it to invalidate itself when any of the peer function
AA results that it uses become invalid. We do this by just tracking the
originating IDs. I've kept it in a somewhat clunky API since some users
of AAResults are outside the new PM right now. We can clean this API up
if/when those users go away.

Secondly, it uses the registration on the outer analysis manager proxy
to trigger deferred invalidation when a module analysis result becomes
invalid.

I've included test cases that specifically try to trigger use-after-free
in both of these cases and they would crash or hang pretty horribly for
me even without ASan. Now they work nicely.

The `InvalidateAnalysis` utility pass required some tweaking to be
useful in this context and it still is pretty garbage. I'd like to
switch it back to the previous implementation and teach the explicit
invalidate method on the AnalysisManager to take care of correctly
triggering indirect invalidation, but I wanted to go ahead and send this
out so folks could see how all of this stuff works together in practice.
And, you know, that it does actually work. =]

Differential Revision: https://reviews.llvm.org/D27205

llvm-svn: 290595
2016-12-27 08:44:39 +00:00
Chandler Carruth
d911668d9b [PM] Add support for building a default AA pipeline to the PassBuilder.
Pretty boring and lame as-is but necessary. This is definitely a place
we'll end up with extension hooks longer term. =]

Differential Revision: https://reviews.llvm.org/D28076

llvm-svn: 290449
2016-12-23 20:38:19 +00:00
Chandler Carruth
8c6f59de4c [PM] Loosen the check ever so slightly -- MSVC appears to not include
a space after the comma in template arguments with our hacky type name
system.

llvm-svn: 290331
2016-12-22 07:53:20 +00:00
Chandler Carruth
fc56c99646 [PM] Make a couple of CHECK lines a bit more precise, NFC.
I was staring at these and didn't realize these were module-layer
proxies as opposed to some other layer. Justin and I have a plan to
rename things to make the names themselves much easier to reason about,
but I at least want the CHECK lines to be precise for now.

llvm-svn: 290328
2016-12-22 07:14:35 +00:00
Chandler Carruth
2ed363a464 [PM] Introduce a reasonable port of the main per-module pass pipeline
from the old pass manager in the new one.

I'm not trying to support (initially) the numerous options that are
currently available to customize the pass pipeline. If we end up really
wanting them, we can add them later, but I suspect many are no longer
interesting. The simplicity of omitting them will help a lot as we sort
out what the pipeline should look like in the new PM.

I've also documented to the best of my ability *why* each pass or group
of passes is used so that reading the pipeline is more helpful. In many
cases I think we have some questionable choices of ordering and I've
left FIXME comments in place so we know what to come back and revisit
going forward. But for now, I've left it as similar to the current
pipeline as I could.

Lastly, I've had to comment out several places where passes are not
ported to the new pass manager or where the loop pass infrastructure is
not yet ready. I did at least fix a few bugs in the loop pass
infrastructure uncovered by running the full pipeline, but I didn't want
to go too far in this patch -- I'll come back and re-enable these as the
infrastructure comes online. But I'd like to keep the comments in place
because I don't want to lose track of which passes need to be enabled
and where they go.

One thing that seemed like a significant API improvement was to require
that we don't build pipelines for O0. It seems to have no real benefit.

I've also switched back to returning pass managers by value as at this
API layer it feels much more natural to me for composition. But if
others disagree, I'm happy to go back to an output parameter.

I'm not 100% happy with the testing strategy currently, but it seems at
least OK. I may come back and try to refactor or otherwise improve this
in subsequent patches but I wanted to at least get a good starting point
in place.

Differential Revision: https://reviews.llvm.org/D28042

llvm-svn: 290325
2016-12-22 06:59:15 +00:00
Chandler Carruth
c7f5392349 [PM] Further broaden this test's regex as both the CGSCC and Function
inner AM proxies are now being rendered differently.

llvm-svn: 289319
2016-12-10 07:59:59 +00:00
Chandler Carruth
0fd094015d [PM] Try to support the new spelling of one of the proxy names that are
showing up on the build bots.

llvm-svn: 289318
2016-12-10 07:46:51 +00:00
Chandler Carruth
4fc787e70d [PM] Support invalidation of inner analysis managers from a pass over the outer IR unit.
Summary:
This never really got implemented, and was very hard to test before
a lot of the refactoring changes to make things more robust. But now we
can test it thoroughly and cleanly, especially at the CGSCC level.

The core idea is that when an inner analysis manager proxy receives the
invalidation event for the outer IR unit, it needs to walk the inner IR
units and propagate it to the inner analysis manager for each of those
units. For example, each function in the SCC needs to get an
invalidation event when the SCC gets one.

The function / module interaction is somewhat boring here. This really
becomes interesting in the face of analysis-backed IR units. This patch
effectively handles all of the CGSCC layer's needs -- both invalidating
SCC analysis and invalidating function analysis when an SCC gets
invalidated.

However, this second aspect doesn't really handle the
LoopAnalysisManager well at this point. That one will need some change
of design in order to fully integrate, because unlike the call graph,
the entire function behind a LoopAnalysis's results can vanish out from
under us, and we won't even have a cached API to access. I'd like to try
to separate solving the loop problems into a subsequent patch though in
order to keep this more focused so I've adapted them to the API and
updated the tests that immediately fail, but I've not added the level of
testing and validation at that layer that I have at the CGSCC layer.

An important aspect of this change is that the proxy for the
FunctionAnalysisManager at the SCC pass layer doesn't work like the
other proxies for an inner IR unit as it doesn't directly manage the
FunctionAnalysisManager and invalidation or clearing of it. This would
create an ever worsening problem of dual ownership of this
responsibility, split between the module-level FAM proxy and this
SCC-level FAM proxy. Instead, this patch changes the SCC-level FAM proxy
to work in terms of the module-level proxy and defer to it to handle
much of the updates. It only does SCC-specific invalidation. This will
become more important in subsequent patches that support more complex
invalidaiton scenarios.

Reviewers: jlebar

Subscribers: mehdi_amini, mcrosier, mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D27197

llvm-svn: 289317
2016-12-10 06:34:44 +00:00
Peter Collingbourne
0cd9b6d885 Analysis: gep inbounds (gep inbounds (...)) is inbounds.
Differential Revision: https://reviews.llvm.org/D26441

llvm-svn: 287604
2016-11-22 01:03:40 +00:00
Matthias Braun
643a05ab19 Statistic/Timer: Include timers in PrintStatisticsJSON().
Differential Revision: https://reviews.llvm.org/D25588

llvm-svn: 287370
2016-11-18 19:43:24 +00:00
Dehao Chen
8606f5bffd Enable Loop Sink pass for functions that has profile.
Summary: For functions with profile data, we are confident that loop sink will be optimal in sinking code.

Reviewers: davidxl, hfinkel

Subscribers: mehdi_amini, mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D26155

llvm-svn: 286325
2016-11-09 00:58:19 +00:00
Reid Kleckner
7dfe7f827f [lit] Work around Windows MSys command line tokenization bug
Summary:
This will allow us to revert LLD r284768, which added spaces to get MSys
echo to print what we want.

Reviewers: ruiu, inglorion, rafael

Subscribers: modocache, llvm-commits

Differential Revision: https://reviews.llvm.org/D26009

llvm-svn: 285237
2016-10-26 20:29:27 +00:00
Sriraman Tallam
0bea49c555 [PM] Port CFGViewer and CFGPrinter to the new Pass Manager
Differential Revision: https://reviews.llvm.org/D24592

llvm-svn: 281640
2016-09-15 18:35:27 +00:00
Chandler Carruth
94942f5c00 [PM] Introduce basic update capabilities to the new PM's CGSCC pass
manager, including both plumbing and logic to handle function pass
updates.

There are three fundamentally tied changes here:
1) Plumbing *some* mechanism for updating the CGSCC pass manager as the
   CG changes while passes are running.
2) Changing the CGSCC pass manager infrastructure to have support for
   the underlying graph to mutate mid-pass run.
3) Actually updating the CG after function passes run.

I can separate them if necessary, but I think its really useful to have
them together as the needs of #3 drove #2, and that in turn drove #1.

The plumbing technique is to extend the "run" method signature with
extra arguments. We provide the call graph that intrinsically is
available as it is the basis of the pass manager's IR units, and an
output parameter that records the results of updating the call graph
during an SCC passes's run. Note that "...UpdateResult" isn't a *great*
name here... suggestions very welcome.

I tried a pretty frustrating number of different data structures and such
for the innards of the update result. Every other one failed for one
reason or another. Sometimes I just couldn't keep the layers of
complexity right in my head. The thing that really worked was to just
directly provide access to the underlying structures used to walk the
call graph so that their updates could be informed by the *particular*
nature of the change to the graph.

The technique for how to make the pass management infrastructure cope
with mutating graphs was also something that took a really, really large
number of iterations to get to a place where I was happy. Here are some
of the considerations that drove the design:

- We operate at three levels within the infrastructure: RefSCC, SCC, and
  Node. In each case, we are working bottom up and so we want to
  continue to iterate on the "lowest" node as the graph changes. Look at
  how we iterate over nodes in an SCC running function passes as those
  function passes mutate the CG. We continue to iterate on the "lowest"
  SCC, which is the one that continues to contain the function just
  processed.

- The call graph structure re-uses SCCs (and RefSCCs) during mutation
  events for the *highest* entry in the resulting new subgraph, not the
  lowest. This means that it is necessary to continually update the
  current SCC or RefSCC as it shifts. This is really surprising and
  subtle, and took a long time for me to work out. I actually tried
  changing the call graph to provide the opposite behavior, and it
  breaks *EVERYTHING*. The graph update algorithms are really deeply
  tied to this particualr pattern.

- When SCCs or RefSCCs are split apart and refined and we continually
  re-pin our processing to the bottom one in the subgraph, we need to
  enqueue the newly formed SCCs and RefSCCs for subsequent processing.
  Queuing them presents a few challenges:
  1) SCCs and RefSCCs use wildly different iteration strategies at
     a high level. We end up needing to converge them on worklist
     approaches that can be extended in order to be able to handle the
     mutations.
  2) The order of the enqueuing need to remain bottom-up post-order so
     that we don't get surprising order of visitation for things like
     the inliner.
  3) We need the worklists to have set semantics so we don't duplicate
     things endlessly. We don't need a *persistent* set though because
     we always keep processing the bottom node!!!! This is super, super
     surprising to me and took a long time to convince myself this is
     correct, but I'm pretty sure it is... Once we sink down to the
     bottom node, we can't re-split out the same node in any way, and
     the postorder of the current queue is fixed and unchanging.
  4) We need to make sure that the "current" SCC or RefSCC actually gets
     enqueued here such that we re-visit it because we continue
     processing a *new*, *bottom* SCC/RefSCC.

- We also need the ability to *skip* SCCs and RefSCCs that get merged
  into a larger component. We even need the ability to skip *nodes* from
  an SCC that are no longer part of that SCC.

This led to the design you see in the patch which uses SetVector-based
worklists. The RefSCC worklist is always empty until an update occurs
and is just used to handle those RefSCCs created by updates as the
others don't even exist yet and are formed on-demand during the
bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and
we push new SCCs onto it and blacklist existing SCCs on it to get the
desired processing.

We then *directly* update these when updating the call graph as I was
never able to find a satisfactory abstraction around the update
strategy.

Finally, we need to compute the updates for function passes. This is
mostly used as an initial customer of all the update mechanisms to drive
their design to at least cover some real set of use cases. There are
a bunch of interesting things that came out of doing this:

- It is really nice to do this a function at a time because that
  function is likely hot in the cache. This means we want even the
  function pass adaptor to support online updates to the call graph!

- To update the call graph after arbitrary function pass mutations is
  quite hard. We have to build a fairly comprehensive set of
  data structures and then process them. Fortunately, some of this code
  is related to the code for building the cal graph in the first place.
  Unfortunately, very little of it makes any sense to share because the
  nature of what we're doing is so very different. I've factored out the
  one part that made sense at least.

- We need to transfer these updates into the various structures for the
  CGSCC pass manager. Once those were more sanely worked out, this
  became relatively easier. But some of those needs necessitated changes
  to the LazyCallGraph interface to make it significantly easier to
  extract the changed SCCs from an update operation.

- We also need to update the CGSCC analysis manager as the shape of the
  graph changes. When an SCC is merged away we need to clear analyses
  associated with it from the analysis manager which we didn't have
  support for in the analysis manager infrsatructure. New SCCs are easy!
  But then we have the case that the original SCC has its shape changed
  but remains in the call graph. There we need to *invalidate* the
  analyses associated with it.

- We also need to invalidate analyses after we *finish* processing an
  SCC. But the analyses we need to invalidate here are *only those for
  the newly updated SCC*!!! Because we only continue processing the
  bottom SCC, if we split SCCs apart the original one gets invalidated
  once when its shape changes and is not processed farther so its
  analyses will be correct. It is the bottom SCC which continues being
  processed and needs to have the "normal" invalidation done based on
  the preserved analyses set.

All of this is mostly background and context for the changes here.

Many thanks to all the reviewers who helped here. Especially Sanjoy who
caught several interesting bugs in the graph algorithms, David, Sean,
and others who all helped with feedback.

Differential Revision: http://reviews.llvm.org/D21464

llvm-svn: 279618
2016-08-24 09:37:14 +00:00
Chandler Carruth
7dc472d231 [PM] Introduce an abstraction for all the analyses over a particular IR
unit for use in the PreservedAnalyses set.

This doesn't have any important functional change yet but it cleans
things up and makes the analysis substantially more efficient by
avoiding querying through the type erasure for every analysis.

I also think it makes it much easier to reason about how analyses are
preserved when walking across pass managers and across IR unit
abstractions.

Thanks to Sean and Mehdi both for the comments and suggestions.

Differential Revision: https://reviews.llvm.org/D23691

llvm-svn: 279360
2016-08-20 04:57:28 +00:00
Chandler Carruth
824dbd8926 [PM] Change the name of the repeating utility to something less
overloaded (and simpler).

Sean rightly pointed out in code review that we've started using
"wrapper pass" as a specific part of the old pass manager, and in fact
it is more applicable there. Here, we really have a pass *template* to
build a repeated pass, so call it that.

llvm-svn: 277689
2016-08-04 03:52:53 +00:00
Matthias Braun
765676aa04 opt-bisect-legacy-pass-manager.ll: Test only works with default triple configured
llvm-svn: 277645
2016-08-03 20:28:19 +00:00
Chandler Carruth
9c54dde4a2 [PM] Add a generic 'repeat N times' pass wrapper to the new pass
manager.

While this has some utility for debugging and testing on its own, it is
primarily intended to demonstrate the technique for adding custom
wrappers that can provide more interesting interation behavior in
a nice, orthogonal, and composable layer.

Being able to write these kinds of very dynamic and customized controls
for running passes was one of the motivating use cases of the new pass
manager design, and this gives a hint at how they might look. The actual
logic is tiny here, and most of this is just wiring in the pipeline
parsing so that this can be widely used.

I'm adding this now to show the wiring without a lot of business logic.
This is a precursor patch for showing how a "iterate up to N times as
long as we devirtualize a call" utility can be added as a separable and
composable component along side the CGSCC pass management.

Differential Revision: https://reviews.llvm.org/D22405

llvm-svn: 277581
2016-08-03 07:44:48 +00:00
Chandler Carruth
9c8020399d [PM] Significantly refactor the pass pipeline parsing to be easier to
reason about and less error prone.

The core idea is to fully parse the text without trying to identify
passes or structure. This is done with a single state machine. There
were various bugs in the logic around this previously that were repeated
and scattered across the code. Having a single routine makes it much
easier to fix and get correct. For example, this routine doesn't suffer
from PR28577.

Then the actual pass construction is handled using *much* easier to read
code and simple loops, with particular pass manager construction sunk to
live with other pass construction. This is especially nice as the pass
managers *are* in fact passes.

Finally, the "implicit" pass manager synthesis is done much more simply
by forming "pre-parsed" structures rather than having to duplicate tons
of logic.

One of the bugs fixed by this was evident in the tests where we accepted
a pipeline that wasn't really well formed. Another bug is PR28577 for
which I have added a test case.

The code is less efficient than the previous code but I'm really hoping
that's not a priority. ;]

Thanks to Sean for the review!

Differential Revision: https://reviews.llvm.org/D22724

llvm-svn: 277561
2016-08-03 03:21:41 +00:00
Andrew Kaylor
224e895f2f Temporarily remove one test run line to unblock PPC bots.
llvm-svn: 274812
2016-07-08 00:32:58 +00:00
Andrew Kaylor
c633e5a584 Include SelectionDAGISel in the opt-bisect process
Differential Revision: http://reviews.llvm.org/D21143

llvm-svn: 274786
2016-07-07 18:55:02 +00:00
Chandler Carruth
7d70986c58 [PM] Improve the debugging and logging facilities of the CGSCC bits of
the new pass manager.

This adds operator<< overloads for the various bits of the
LazyCallGraph, dump methods for use from the debugger, and debug logging
using them to the CGSCC pass manager.

Having this was essential for debugging the call graph update patch, and
I've extracted what I could from that patch here to minimize the delta.

llvm-svn: 273961
2016-06-27 23:26:08 +00:00
Matthias Braun
cf19d2a645 Statistic: Add machine parseable json output
- We lacked a short unique identifier for a statistics, so I renamed the
  current "Name" field that just contained the DEBUG_TYPE name of the
  current file to DebugType and added a new "Name" field that contains
  the C++ identifier of the statistic variable.
- Add the -stats-json option which outputs statistics in json format.

Differential Revision: http://reviews.llvm.org/D20995

llvm-svn: 272826
2016-06-15 20:19:16 +00:00
Peter Collingbourne
5dcb77e9fb IR: Introduce local_unnamed_addr attribute.
If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing unnamed_addr attribute in that it only describes a local property
of the module rather than a global property of the symbol.

This attribute is intended to be used by the code generator and LTO to allow
the linker to decide whether the global needs to be in the symbol table. It is
possible to exclude a global from the symbol table if three things are true:
- This attribute is present on every instance of the global (which means that
  the normal rule that the global must have a unique address can be broken without
  being observable by the program by performing comparisons against the global's
  address)
- The global has linkonce_odr linkage (which means that each linkage unit must have
  its own copy of the global if it requires one, and the copy in each linkage unit
  must be the same)
- It is a constant or a function (which means that the program cannot observe that
  the unique-address rule has been broken by writing to the global)

Although this attribute could in principle be computed from the module
contents, LTO clients (i.e. linkers) will normally need to be able to compute
this property as part of symbol resolution, and it would be inefficient to
materialize every module just to compute it.

See:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.html
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html
for earlier discussion.

Part of the fix for PR27553.

Differential Revision: http://reviews.llvm.org/D20348

llvm-svn: 272709
2016-06-14 21:01:22 +00:00
Manuel Jacob
d6babe096d [PM] Schedule InstSimplify after late LICM run, to clean up LCSSA nodes.
Summary:
The module pass pipeline includes a late LICM run after loop
unrolling.  LCSSA is implicitly run as a pass dependency of LICM.  However no
cleanup pass was run after this, so the LCSSA nodes ended in the optimized output.

Reviewers: hfinkel, mehdi_amini

Subscribers: majnemer, bruno, mzolotukhin, mehdi_amini, llvm-commits

Differential Revision: http://reviews.llvm.org/D20606

llvm-svn: 271602
2016-06-02 22:14:26 +00:00
Andrew Kaylor
bb1fbe49cd Update the stack coloring pass to remove lifetime intrinsics in the optnone/opt-bisect skip case.
Differential Revision: http://reviews.llvm.org/D20453

llvm-svn: 271068
2016-05-27 22:56:49 +00:00
Andrew Kaylor
70edd780c7 Add opt-bisect support to additional passes that can be skipped
Differential Revision: http://reviews.llvm.org/D19882

llvm-svn: 268457
2016-05-03 22:32:30 +00:00
Mehdi Amini
c756730763 Move "Eliminate Available Externally" immediately after the inliner
This pass is supposed to reduce the size of the IR for compile time
purpose. We should run it ASAP, except when we prepare for LTO or
ThinLTO, and we want to keep them available for link-time inline.

Differential Revision: http://reviews.llvm.org/D19813

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 268394
2016-05-03 15:46:00 +00:00
Mehdi Amini
7b2daaaedb Move createReversePostOrderFunctionAttrsPass right after the inliner is done
This is where it was originally, until LoopVersioningLICM was
inserted before in r259986, I don't believe it was on purpose.

Differential Revision: http://reviews.llvm.org/D19809

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 268252
2016-05-02 16:53:16 +00:00
Nico Weber
a8ed675976 Try to get ResponseFile.ll passing on Windows after r267556.
llvm-svn: 267599
2016-04-26 20:32:51 +00:00
Andrew Kaylor
653d361880 Re-commit optimization bisect support (r267022) without new pass manager support.
The original commit was reverted because of a buildbot problem with LazyCallGraph::SCC handling (not related to the OptBisect handling).

Differential Revision: http://reviews.llvm.org/D19172

llvm-svn: 267231
2016-04-22 22:06:11 +00:00
Vedant Kumar
b6cc52b7d8 Revert "Initial implementation of optimization bisect support."
This reverts commit r267022, due to an ASan failure:

  http://lab.llvm.org:8080/green/job/clang-stage2-cmake-RgSan_check/1549

llvm-svn: 267115
2016-04-22 06:51:37 +00:00
Andrew Kaylor
fd49f275f8 Initial implementation of optimization bisect support.
This patch implements a optimization bisect feature, which will allow optimizations to be selectively disabled at compile time in order to track down test failures that are caused by incorrect optimizations.

The bisection is enabled using a new command line option (-opt-bisect-limit).  Individual passes that may be skipped call the OptBisect object (via an LLVMContext) to see if they should be skipped based on the bisect limit.  A finer level of control (disabling individual transformations) can be managed through an addition OptBisect method, but this is not yet used.

The skip checking in this implementation is based on (and replaces) the skipOptnoneFunction check.  Where that check was being called, a new call has been inserted in its place which checks the bisect limit and the optnone attribute.  A new function call has been added for module and SCC passes that behaves in a similar way.

Differential Revision: http://reviews.llvm.org/D19172

llvm-svn: 267022
2016-04-21 17:58:54 +00:00
Chandler Carruth
161eaed043 [CG] Add a new pass manager printer pass for the old call graph and
actually finish wiring up the old call graph.

There were bugs in the old call graph that hadn't been caught because it
wasn't being tested. It wasn't being tested because it wasn't in the
pipeline system and we didn't have a printing pass to run in tests. This
fixes all of that.

As for why I'm still keeping the old call graph alive its so that I can
port GlobalsAA to the new pass manager with out forking it to work with
the lazy call graph. That's clearly the right eventual design, but it
seems pragmatic to defer that until its necessary. The old call graph
works just fine for GlobalsAA.

llvm-svn: 263104
2016-03-10 11:24:11 +00:00
Chandler Carruth
4904b56b75 [PM] Port memdep to the new pass manager.
This is a fairly straightforward port to the new pass manager with one
exception. It removes a very questionable use of releaseMemory() in
the old pass to invalidate its caches between runs on a function.
I don't think this is really guaranteed to be safe. I've just used the
more direct port to the new PM to address this by nuking the results
object each time the pass runs. While this could cause some minor malloc
traffic increase, I don't expect the compile time performance hit to be
noticable, and it makes the correctness and other aspects of the pass
much easier to reason about. In some cases, it may make things faster by
making the sets and maps smaller with better locality. Indeed, the
measurements collected by Bruno (thanks!!!) show mostly compile time
improvements.

There is sadly very limited testing at this point as there are only two
tests of memdep, and both rely on GVN. I'll be porting GVN next and that
will exercise this heavily though.

Differential Revision: http://reviews.llvm.org/D17962

llvm-svn: 263082
2016-03-10 00:55:30 +00:00
Chandler Carruth
efc34fd7e6 [PM] Wire up optimization levels and default pipeline construction APIs
in the PassBuilder.

These are really just stubs for now, but they give a nice API surface
that Clang or other tools can start learning about and enabling for
experimentation.

I've also wired up parsing various synthetic module pass names to
generate these set pipelines. This allows the pipelines to be combined
with other passes and have their order controlled, with clear separation
between the *kind* of canned pipeline, and the *level* of optimization
to be used within that canned pipeline.

The most interesting part of this patch is almost certainly the spec for
the different optimization levels. I don't think we can ever have hard
and fast rules that would make it easy to determine whether a particular
optimization makes sense at a particular level -- it will always be in
large part a judgement call. But hopefully this will outline the
expected rationale that should be used, and the direction that the
pipelines should be taken. Much of this was based on a long llvm-dev
discussion I started years ago to try and crystalize the intent behind
these pipelines, and now, at long long last I'm returning to the task of
actually writing it down somewhere that we can cite and try to be
consistent with.

Differential Revision: http://reviews.llvm.org/D12826

llvm-svn: 262196
2016-02-28 22:16:03 +00:00
Chandler Carruth
b38ca77e0f [PM] Loosen the regex for the proxy template name even further to cope
with 'class' keywords in the template arguments and other silliness.

llvm-svn: 262130
2016-02-27 11:07:16 +00:00
Chandler Carruth
634330d245 [PM] Use a boring regex instead of explicitly naming the analysis
manager as some compilers print the typedef name and others print the
"canonical" name of the underlying class template.

This isn't really an important artifact of the test anyways so it seems
fine to just loosen the test assertions here.

llvm-svn: 262129
2016-02-27 10:48:14 +00:00
Chandler Carruth
532f5864dc [PM] Provide two templates for the two directionalities of analysis
manager proxies and use those rather than repeating their definition
four times.

There are real differences between the two directions: outer AMs are
const and don't need to have invalidation tracked. But every proxy in
a particular direction is identical except for the analysis manager type
and the IR unit they proxy into. This makes them prime candidates for
nice templates.

I've started introducing explicit template instantiation declarations
and definitions as well because we really shouldn't be emitting all this
everywhere. I'm going to go back and add the same for the other
templates like this in a follow-up patch.

I've left the analysis manager as an opaque type rather than using two
IR units and requiring it to be an AnalysisManager template
specialization. I think its important that users retain the ability to
provide their own custom analysis management layer and provided it has
the appropriate API everything should Just Work.

llvm-svn: 262127
2016-02-27 10:38:10 +00:00
Chandler Carruth
a25189ea0f [PM] Introduce CRTP mixin base classes to help define passes and
analyses in the new pass manager.

These just handle really basic stuff: turning a type name into a string
statically that is nice to print in logs, and getting a static unique ID
for each analysis.

Sadly, the format of passes in anonymous namespaces makes using their
names in tests really annoying so I've customized the names of the no-op
passes to keep tests sane to read.

This is the first of a few simplifying refactorings for the new pass
manager that should reduce boilerplate and confusion.

llvm-svn: 262004
2016-02-26 11:44:45 +00:00
Chandler Carruth
8e1f184ecc [PM] Add the IR unit type to the pass manager's logging and make all of
the testing more more explicit.

This will currently fail on platforms without support for getTypeName.
While an assert failure seems too harsh, I'm hoping we're OK with the
regression test failure, and I'd like to find out about what platforms
actually exist in this state if there are any so we can get
implementations in place for them.

But if we just can't fix all the host compilers to have a reasonably
portable variant of getTypeName and are worried about xfailing this test
on those platforms, I can add the horrible regular expression magic to
make the tests support "unknown" here as well.

llvm-svn: 261853
2016-02-25 10:27:39 +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
b42444d804 [LPM] Factor all of the loop analysis usage updates into a common helper
routine.

We were getting this wrong in small ways and generally being very
inconsistent about it across loop passes. Instead, let's have a common
place where we do this. One minor downside is that this will require
some analyses like SCEV in more places than they are strictly needed.
However, this seems benign as these analyses are complete no-ops, and
without this consistency we can in many cases end up with the legacy
pass manager scheduling deciding to split up a loop pass pipeline in
order to run the function analysis half-way through. It is very, very
annoying to fix these without just being very pedantic across the board.

The only loop passes I've not updated here are ones that use
AU.setPreservesAll() such as IVUsers (an analysis) and the pass printer.
They seemed less relevant.

With this patch, almost all of the problems in PR24804 around loop pass
pipelines are fixed. The one remaining issue is that we run simplify-cfg
and instcombine in the middle of the loop pass pipeline. We've recently
added some loop variants of these passes that would seem substantially
cleaner to use, but this at least gets us much closer to the previous
state. Notably, the seven loop pass managers is down to three.

I've not updated the loop passes using LoopAccessAnalysis because that
analysis hasn't been fully wired into LoopSimplify/LCSSA, and it isn't
clear that those transforms want to support those forms anyways. They
all run late anyways, so this is harmless. Similarly, LSR is left alone
because it already carefully manages its forms and doesn't need to get
fused into a single loop pass manager with a bunch of other loop passes.

LoopReroll didn't use loop simplified form previously, and I've updated
the test case to match the trivially different output.

Finally, I've also factored all the pass initialization for the passes
that use this technique as well, so that should be done regularly and
reliably.

Thanks to James for the help reviewing and thinking about this stuff,
and Ben for help thinking about it as well!

Differential Revision: http://reviews.llvm.org/D17435

llvm-svn: 261316
2016-02-19 10:45:18 +00:00
Chandler Carruth
ea58c529d8 [LPM] Actually test what the O2 pass pipeline consists of in key places,
especially the *structure* of it with respect to various pass managers.

This uncovers an absolute horror show of problems. This test shows just
how bad PR24804 is: we have a totaly of *seven* loop pass managers in
the main optimization pipeline.

I've tried to comment the various bits to the best of my knowledge, but
more enhancements here would be great.

Also great would be folks adding various test for other pipelines, I'm
focused on trying to fix the O2 pipeline. I just wanted a test to show
what I'm changing.

llvm-svn: 261305
2016-02-19 04:09:40 +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
Chandler Carruth
83293a2122 [PM/AA] Wire BasicAA's new pass manager class up to the pass registry.
This ensures that all of the various pieces are working. The next patch
will wire up commandline-driven alias analysis chain building and allow
BasicAA to work with the AAManager.

llvm-svn: 260838
2016-02-13 23:46:24 +00:00