2014-04-21 19:12:00 +08:00
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//===- CGSCCPassManager.cpp - Managing & running CGSCC passes -------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/CGSCCPassManager.h"
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[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 17:37:14 +08:00
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#include "llvm/IR/CallSite.h"
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2014-04-21 19:12:00 +08:00
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using namespace llvm;
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2016-02-27 18:38:10 +08:00
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namespace llvm {
|
[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 17:37:14 +08:00
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// Explicit instantiations for the core proxy templates.
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template class AnalysisManager<LazyCallGraph::SCC, LazyCallGraph &>;
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template class PassManager<LazyCallGraph::SCC, CGSCCAnalysisManager,
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LazyCallGraph &, CGSCCUpdateResult &>;
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2016-02-27 18:38:10 +08:00
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template class InnerAnalysisManagerProxy<CGSCCAnalysisManager, Module>;
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template class OuterAnalysisManagerProxy<ModuleAnalysisManager,
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2016-08-30 23:47:13 +08:00
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LazyCallGraph::SCC>;
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2016-02-27 18:38:10 +08:00
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template class InnerAnalysisManagerProxy<FunctionAnalysisManager,
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2016-08-30 23:47:13 +08:00
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LazyCallGraph::SCC>;
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2016-02-27 18:38:10 +08:00
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template class OuterAnalysisManagerProxy<CGSCCAnalysisManager, Function>;
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[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 17:37:14 +08:00
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/// Explicitly specialize the pass manager run method to handle call graph
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/// updates.
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template <>
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PreservedAnalyses
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PassManager<LazyCallGraph::SCC, CGSCCAnalysisManager, LazyCallGraph &,
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CGSCCUpdateResult &>::run(LazyCallGraph::SCC &InitialC,
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CGSCCAnalysisManager &AM,
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LazyCallGraph &G, CGSCCUpdateResult &UR) {
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PreservedAnalyses PA = PreservedAnalyses::all();
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if (DebugLogging)
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dbgs() << "Starting CGSCC pass manager run.\n";
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// The SCC may be refined while we are running passes over it, so set up
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// a pointer that we can update.
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LazyCallGraph::SCC *C = &InitialC;
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for (auto &Pass : Passes) {
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if (DebugLogging)
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dbgs() << "Running pass: " << Pass->name() << " on " << *C << "\n";
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PreservedAnalyses PassPA = Pass->run(*C, AM, G, UR);
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// Update the SCC if necessary.
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C = UR.UpdatedC ? UR.UpdatedC : C;
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// Check that we didn't miss any update scenario.
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assert(!UR.InvalidatedSCCs.count(C) && "Processing an invalid SCC!");
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assert(C->begin() != C->end() && "Cannot have an empty SCC!");
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// Update the analysis manager as each pass runs and potentially
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2016-11-28 18:42:21 +08:00
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// invalidates analyses.
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AM.invalidate(*C, PassPA);
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[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 17:37:14 +08:00
|
|
|
|
|
|
|
|
// Finally, we intersect the final preserved analyses to compute the
|
|
|
|
|
// aggregate preserved set for this pass manager.
|
|
|
|
|
PA.intersect(std::move(PassPA));
|
|
|
|
|
|
|
|
|
|
// FIXME: Historically, the pass managers all called the LLVM context's
|
|
|
|
|
// yield function here. We don't have a generic way to acquire the
|
|
|
|
|
// context and it isn't yet clear what the right pattern is for yielding
|
|
|
|
|
// in the new pass manager so it is currently omitted.
|
|
|
|
|
// ...getContext().yield();
|
|
|
|
|
}
|
|
|
|
|
|
2016-11-28 18:42:21 +08:00
|
|
|
// Invaliadtion was handled after each pass in the above loop for the current
|
|
|
|
|
// SCC. Therefore, the remaining analysis results in the AnalysisManager are
|
|
|
|
|
// preserved. We mark this with a set so that we don't need to inspect each
|
|
|
|
|
// one individually.
|
|
|
|
|
PA.preserve<AllAnalysesOn<LazyCallGraph::SCC>>();
|
|
|
|
|
|
[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 17:37:14 +08:00
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Finished CGSCC pass manager run.\n";
|
|
|
|
|
|
|
|
|
|
return PA;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
} // End llvm namespace
|
|
|
|
|
|
|
|
|
|
namespace {
|
|
|
|
|
/// Helper function to update both the \c CGSCCAnalysisManager \p AM and the \c
|
|
|
|
|
/// CGSCCPassManager's \c CGSCCUpdateResult \p UR based on a range of newly
|
|
|
|
|
/// added SCCs.
|
|
|
|
|
///
|
|
|
|
|
/// The range of new SCCs must be in postorder already. The SCC they were split
|
|
|
|
|
/// out of must be provided as \p C. The current node being mutated and
|
|
|
|
|
/// triggering updates must be passed as \p N.
|
|
|
|
|
///
|
|
|
|
|
/// This function returns the SCC containing \p N. This will be either \p C if
|
|
|
|
|
/// no new SCCs have been split out, or it will be the new SCC containing \p N.
|
|
|
|
|
template <typename SCCRangeT>
|
|
|
|
|
LazyCallGraph::SCC *
|
|
|
|
|
incorporateNewSCCRange(const SCCRangeT &NewSCCRange, LazyCallGraph &G,
|
|
|
|
|
LazyCallGraph::Node &N, LazyCallGraph::SCC *C,
|
|
|
|
|
CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR,
|
|
|
|
|
bool DebugLogging = false) {
|
|
|
|
|
typedef LazyCallGraph::SCC SCC;
|
|
|
|
|
|
|
|
|
|
if (NewSCCRange.begin() == NewSCCRange.end())
|
|
|
|
|
return C;
|
|
|
|
|
|
|
|
|
|
// Invalidate the analyses of the current SCC and add it to the worklist since
|
|
|
|
|
// it has changed its shape.
|
|
|
|
|
AM.invalidate(*C, PreservedAnalyses::none());
|
|
|
|
|
UR.CWorklist.insert(C);
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Enqueuing the existing SCC in the worklist:" << *C << "\n";
|
|
|
|
|
|
|
|
|
|
SCC *OldC = C;
|
|
|
|
|
(void)OldC;
|
|
|
|
|
|
|
|
|
|
// Update the current SCC. Note that if we have new SCCs, this must actually
|
|
|
|
|
// change the SCC.
|
|
|
|
|
assert(C != &*NewSCCRange.begin() &&
|
|
|
|
|
"Cannot insert new SCCs without changing current SCC!");
|
|
|
|
|
C = &*NewSCCRange.begin();
|
|
|
|
|
assert(G.lookupSCC(N) == C && "Failed to update current SCC!");
|
|
|
|
|
|
|
|
|
|
for (SCC &NewC :
|
|
|
|
|
reverse(make_range(std::next(NewSCCRange.begin()), NewSCCRange.end()))) {
|
|
|
|
|
assert(C != &NewC && "No need to re-visit the current SCC!");
|
|
|
|
|
assert(OldC != &NewC && "Already handled the original SCC!");
|
|
|
|
|
UR.CWorklist.insert(&NewC);
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Enqueuing a newly formed SCC:" << NewC << "\n";
|
|
|
|
|
}
|
|
|
|
|
return C;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
LazyCallGraph::SCC &llvm::updateCGAndAnalysisManagerForFunctionPass(
|
|
|
|
|
LazyCallGraph &G, LazyCallGraph::SCC &InitialC, LazyCallGraph::Node &N,
|
|
|
|
|
CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR, bool DebugLogging) {
|
|
|
|
|
typedef LazyCallGraph::Node Node;
|
|
|
|
|
typedef LazyCallGraph::Edge Edge;
|
|
|
|
|
typedef LazyCallGraph::SCC SCC;
|
|
|
|
|
typedef LazyCallGraph::RefSCC RefSCC;
|
|
|
|
|
|
|
|
|
|
RefSCC &InitialRC = InitialC.getOuterRefSCC();
|
|
|
|
|
SCC *C = &InitialC;
|
|
|
|
|
RefSCC *RC = &InitialRC;
|
|
|
|
|
Function &F = N.getFunction();
|
|
|
|
|
|
|
|
|
|
// Walk the function body and build up the set of retained, promoted, and
|
|
|
|
|
// demoted edges.
|
|
|
|
|
SmallVector<Constant *, 16> Worklist;
|
|
|
|
|
SmallPtrSet<Constant *, 16> Visited;
|
|
|
|
|
SmallPtrSet<Function *, 16> RetainedEdges;
|
|
|
|
|
SmallSetVector<Function *, 4> PromotedRefTargets;
|
|
|
|
|
SmallSetVector<Function *, 4> DemotedCallTargets;
|
|
|
|
|
// First walk the function and handle all called functions. We do this first
|
|
|
|
|
// because if there is a single call edge, whether there are ref edges is
|
|
|
|
|
// irrelevant.
|
|
|
|
|
for (BasicBlock &BB : F)
|
|
|
|
|
for (Instruction &I : BB)
|
|
|
|
|
if (auto CS = CallSite(&I))
|
|
|
|
|
if (Function *Callee = CS.getCalledFunction())
|
|
|
|
|
if (Visited.insert(Callee).second && !Callee->isDeclaration()) {
|
|
|
|
|
const Edge *E = N.lookup(*Callee);
|
|
|
|
|
// FIXME: We should really handle adding new calls. While it will
|
|
|
|
|
// make downstream usage more complex, there is no fundamental
|
|
|
|
|
// limitation and it will allow passes within the CGSCC to be a bit
|
|
|
|
|
// more flexible in what transforms they can do. Until then, we
|
|
|
|
|
// verify that new calls haven't been introduced.
|
|
|
|
|
assert(E && "No function transformations should introduce *new* "
|
|
|
|
|
"call edges! Any new calls should be modeled as "
|
|
|
|
|
"promoted existing ref edges!");
|
|
|
|
|
RetainedEdges.insert(Callee);
|
|
|
|
|
if (!E->isCall())
|
|
|
|
|
PromotedRefTargets.insert(Callee);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Now walk all references.
|
|
|
|
|
for (BasicBlock &BB : F)
|
|
|
|
|
for (Instruction &I : BB) {
|
|
|
|
|
for (Value *Op : I.operand_values())
|
|
|
|
|
if (Constant *C = dyn_cast<Constant>(Op))
|
|
|
|
|
if (Visited.insert(C).second)
|
|
|
|
|
Worklist.push_back(C);
|
|
|
|
|
|
|
|
|
|
LazyCallGraph::visitReferences(Worklist, Visited, [&](Function &Referee) {
|
|
|
|
|
// Skip declarations.
|
|
|
|
|
if (Referee.isDeclaration())
|
|
|
|
|
return;
|
|
|
|
|
|
|
|
|
|
const Edge *E = N.lookup(Referee);
|
|
|
|
|
// FIXME: Similarly to new calls, we also currently preclude
|
|
|
|
|
// introducing new references. See above for details.
|
|
|
|
|
assert(E && "No function transformations should introduce *new* ref "
|
|
|
|
|
"edges! Any new ref edges would require IPO which "
|
|
|
|
|
"function passes aren't allowed to do!");
|
|
|
|
|
RetainedEdges.insert(&Referee);
|
|
|
|
|
if (E->isCall())
|
|
|
|
|
DemotedCallTargets.insert(&Referee);
|
|
|
|
|
});
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// First remove all of the edges that are no longer present in this function.
|
|
|
|
|
// We have to build a list of dead targets first and then remove them as the
|
|
|
|
|
// data structures will all be invalidated by removing them.
|
|
|
|
|
SmallVector<PointerIntPair<Node *, 1, Edge::Kind>, 4> DeadTargets;
|
|
|
|
|
for (Edge &E : N)
|
|
|
|
|
if (!RetainedEdges.count(&E.getFunction()))
|
|
|
|
|
DeadTargets.push_back({E.getNode(), E.getKind()});
|
|
|
|
|
for (auto DeadTarget : DeadTargets) {
|
|
|
|
|
Node &TargetN = *DeadTarget.getPointer();
|
|
|
|
|
bool IsCall = DeadTarget.getInt() == Edge::Call;
|
|
|
|
|
SCC &TargetC = *G.lookupSCC(TargetN);
|
|
|
|
|
RefSCC &TargetRC = TargetC.getOuterRefSCC();
|
|
|
|
|
|
|
|
|
|
if (&TargetRC != RC) {
|
|
|
|
|
RC->removeOutgoingEdge(N, TargetN);
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Deleting outgoing edge from '" << N << "' to '" << TargetN
|
|
|
|
|
<< "'\n";
|
|
|
|
|
continue;
|
|
|
|
|
}
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Deleting internal " << (IsCall ? "call" : "ref")
|
|
|
|
|
<< " edge from '" << N << "' to '" << TargetN << "'\n";
|
|
|
|
|
|
|
|
|
|
if (IsCall)
|
|
|
|
|
C = incorporateNewSCCRange(RC->switchInternalEdgeToRef(N, TargetN), G, N,
|
|
|
|
|
C, AM, UR, DebugLogging);
|
|
|
|
|
|
|
|
|
|
auto NewRefSCCs = RC->removeInternalRefEdge(N, TargetN);
|
|
|
|
|
if (!NewRefSCCs.empty()) {
|
|
|
|
|
// Note that we don't bother to invalidate analyses as ref-edge
|
|
|
|
|
// connectivity is not really observable in any way and is intended
|
|
|
|
|
// exclusively to be used for ordering of transforms rather than for
|
|
|
|
|
// analysis conclusions.
|
|
|
|
|
|
|
|
|
|
// The RC worklist is in reverse postorder, so we first enqueue the
|
|
|
|
|
// current RefSCC as it will remain the parent of all split RefSCCs, then
|
|
|
|
|
// we enqueue the new ones in RPO except for the one which contains the
|
|
|
|
|
// source node as that is the "bottom" we will continue processing in the
|
|
|
|
|
// bottom-up walk.
|
|
|
|
|
UR.RCWorklist.insert(RC);
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Enqueuing the existing RefSCC in the update worklist: "
|
|
|
|
|
<< *RC << "\n";
|
|
|
|
|
// Update the RC to the "bottom".
|
|
|
|
|
assert(G.lookupSCC(N) == C && "Changed the SCC when splitting RefSCCs!");
|
|
|
|
|
RC = &C->getOuterRefSCC();
|
|
|
|
|
assert(G.lookupRefSCC(N) == RC && "Failed to update current RefSCC!");
|
|
|
|
|
for (RefSCC *NewRC : reverse(NewRefSCCs))
|
|
|
|
|
if (NewRC != RC) {
|
|
|
|
|
UR.RCWorklist.insert(NewRC);
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Enqueuing a new RefSCC in the update worklist: "
|
|
|
|
|
<< *NewRC << "\n";
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Next demote all the call edges that are now ref edges. This helps make
|
|
|
|
|
// the SCCs small which should minimize the work below as we don't want to
|
|
|
|
|
// form cycles that this would break.
|
|
|
|
|
for (Function *RefTarget : DemotedCallTargets) {
|
|
|
|
|
Node &TargetN = *G.lookup(*RefTarget);
|
|
|
|
|
SCC &TargetC = *G.lookupSCC(TargetN);
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RefSCC &TargetRC = TargetC.getOuterRefSCC();
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// The easy case is when the target RefSCC is not this RefSCC. This is
|
|
|
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// only supported when the target RefSCC is a child of this RefSCC.
|
|
|
|
|
if (&TargetRC != RC) {
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|
|
|
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assert(RC->isAncestorOf(TargetRC) &&
|
|
|
|
|
"Cannot potentially form RefSCC cycles here!");
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|
|
|
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RC->switchOutgoingEdgeToRef(N, TargetN);
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|
|
|
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if (DebugLogging)
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|
|
|
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dbgs() << "Switch outgoing call edge to a ref edge from '" << N
|
|
|
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<< "' to '" << TargetN << "'\n";
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|
|
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|
continue;
|
|
|
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|
}
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|
|
|
|
|
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|
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// Otherwise we are switching an internal call edge to a ref edge. This
|
|
|
|
|
// may split up some SCCs.
|
|
|
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|
C = incorporateNewSCCRange(RC->switchInternalEdgeToRef(N, TargetN), G, N, C,
|
|
|
|
|
AM, UR, DebugLogging);
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|
|
|
|
}
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|
|
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|
|
|
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|
// Now promote ref edges into call edges.
|
|
|
|
|
for (Function *CallTarget : PromotedRefTargets) {
|
|
|
|
|
Node &TargetN = *G.lookup(*CallTarget);
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|
|
|
|
SCC &TargetC = *G.lookupSCC(TargetN);
|
|
|
|
|
RefSCC &TargetRC = TargetC.getOuterRefSCC();
|
|
|
|
|
|
|
|
|
|
// The easy case is when the target RefSCC is not this RefSCC. This is
|
|
|
|
|
// only supported when the target RefSCC is a child of this RefSCC.
|
|
|
|
|
if (&TargetRC != RC) {
|
|
|
|
|
assert(RC->isAncestorOf(TargetRC) &&
|
|
|
|
|
"Cannot potentially form RefSCC cycles here!");
|
|
|
|
|
RC->switchOutgoingEdgeToCall(N, TargetN);
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Switch outgoing ref edge to a call edge from '" << N
|
|
|
|
|
<< "' to '" << TargetN << "'\n";
|
|
|
|
|
continue;
|
|
|
|
|
}
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Switch an internal ref edge to a call edge from '" << N
|
|
|
|
|
<< "' to '" << TargetN << "'\n";
|
|
|
|
|
|
|
|
|
|
// Otherwise we are switching an internal ref edge to a call edge. This
|
|
|
|
|
// may merge away some SCCs, and we add those to the UpdateResult. We also
|
|
|
|
|
// need to make sure to update the worklist in the event SCCs have moved
|
|
|
|
|
// before the current one in the post-order sequence.
|
|
|
|
|
auto InitialSCCIndex = RC->find(*C) - RC->begin();
|
|
|
|
|
auto InvalidatedSCCs = RC->switchInternalEdgeToCall(N, TargetN);
|
|
|
|
|
if (!InvalidatedSCCs.empty()) {
|
|
|
|
|
C = &TargetC;
|
|
|
|
|
assert(G.lookupSCC(N) == C && "Failed to update current SCC!");
|
|
|
|
|
|
|
|
|
|
// Any analyses cached for this SCC are no longer precise as the shape
|
|
|
|
|
// has changed by introducing this cycle.
|
|
|
|
|
AM.invalidate(*C, PreservedAnalyses::none());
|
|
|
|
|
|
|
|
|
|
for (SCC *InvalidatedC : InvalidatedSCCs) {
|
|
|
|
|
assert(InvalidatedC != C && "Cannot invalidate the current SCC!");
|
|
|
|
|
UR.InvalidatedSCCs.insert(InvalidatedC);
|
|
|
|
|
|
|
|
|
|
// Also clear any cached analyses for the SCCs that are dead. This
|
|
|
|
|
// isn't really necessary for correctness but can release memory.
|
|
|
|
|
AM.clear(*InvalidatedC);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
auto NewSCCIndex = RC->find(*C) - RC->begin();
|
|
|
|
|
if (InitialSCCIndex < NewSCCIndex) {
|
|
|
|
|
// Put our current SCC back onto the worklist as we'll visit other SCCs
|
|
|
|
|
// that are now definitively ordered prior to the current one in the
|
|
|
|
|
// post-order sequence, and may end up observing more precise context to
|
|
|
|
|
// optimize the current SCC.
|
|
|
|
|
UR.CWorklist.insert(C);
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Enqueuing the existing SCC in the worklist: " << *C << "\n";
|
|
|
|
|
// Enqueue in reverse order as we pop off the back of the worklist.
|
|
|
|
|
for (SCC &MovedC : reverse(make_range(RC->begin() + InitialSCCIndex,
|
|
|
|
|
RC->begin() + NewSCCIndex))) {
|
|
|
|
|
UR.CWorklist.insert(&MovedC);
|
|
|
|
|
if (DebugLogging)
|
|
|
|
|
dbgs() << "Enqueuing a newly earlier in post-order SCC: " << MovedC
|
|
|
|
|
<< "\n";
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
assert(!UR.InvalidatedSCCs.count(C) && "Invalidated the current SCC!");
|
|
|
|
|
assert(!UR.InvalidatedRefSCCs.count(RC) && "Invalidated the current RefSCC!");
|
|
|
|
|
assert(&C->getOuterRefSCC() == RC && "Current SCC not in current RefSCC!");
|
|
|
|
|
|
|
|
|
|
// Record the current RefSCC and SCC for higher layers of the CGSCC pass
|
|
|
|
|
// manager now that all the updates have been applied.
|
|
|
|
|
if (RC != &InitialRC)
|
|
|
|
|
UR.UpdatedRC = RC;
|
|
|
|
|
if (C != &InitialC)
|
|
|
|
|
UR.UpdatedC = C;
|
|
|
|
|
|
|
|
|
|
return *C;
|
2014-04-21 19:12:00 +08:00
|
|
|
}
|