The three different concerns that the ControlReducer used to deal with
are now properly separated into
a.) DeadCodeElimination, which is a regular AdvancedReducer, that
propagates Dead via control edges,
b.) CommonOperatorReducer, which does strength reduction on common
operators (i.e. Branch, Phi, and friends), and
c.) GraphTrimming, which removes dead->live edges from the graph.
This will make it possible to run the DeadCodeElimination together with
other passes that actually introduce Dead nodes, i.e. typed lowering;
and it opens the door for general inlining without two stage fix point
iteration.
To make the DeadCodeElimination easier and more uniform, we basically
reverted the introduction of DeadValue and DeadEffect, and changed the
Dead operator to produce control, value and effect. Note however that
this is not a requirement, but merely a way to make dead propagation
easier and more uniform. We could always go back and decide to have
different Dead operators if some other change requires that.
Note that there are several additional opportunities for cleanup now,
i.e. OSR deconstruction could be a regular reducer now, and we don't
need to use TheHole as dead value marker in the GraphReducer. And we can
actually run the dead code elimination together with the other passes
instead of using separate passes over the graph. We will do this in
follow up CLs.
R=jarin@chromium.org, mstarzinger@chromium.org
Review URL: https://codereview.chromium.org/1193833002
Cr-Commit-Position: refs/heads/master@{#29146}
Up until now that was still mixed with control reduction in the
ControlReducer. This separation allows us to remove the horrible
Reducer::Finish hack and also do graph trimming at more appropriate
places in the pipeline (i.e. trim dead nodes after generic lowering,
which can also make nodes dead).
R=jarin@chromium.org,mstarzinger@chromium.org
Review URL: https://codereview.chromium.org/1188433010
Cr-Commit-Position: refs/heads/master@{#29077}
The SimplifiedOperatorReducer is (mostly) unused, except for the very
rough store elimination, and just eats compilation time.
R=jarin@chromium.org
Review URL: https://codereview.chromium.org/1162563002
Cr-Commit-Position: refs/heads/master@{#28673}
This introduces V8.MemoryHeapCommitted and V8.MemoryHeapUsed histograms.
In contrast to the existing memory histograms, the new histograms are uniform in time, i.e. their samples happen at regular time intervals. The --histogram-interval specifies the length of the interval.
We implement this by linearly interpolating memory stats between GC and idle notification events.
BUG=chromium:485472
LOG=NO
Review URL: https://codereview.chromium.org/1125683004
Cr-Commit-Position: refs/heads/master@{#28292}
An AdvancedReducer is basically a regular Reducer with an editor
that can perform graph editing operations beyond changing or
replacing the node that is currently being reduced. The GraphReducer
is the default implementation of the AdvancedReducer::Editor interface.
The ControlReducerImpl is now just an AdvancedReducer, which
temporarily requires a Finish method in the reducer to implement
the dead node trimming until we move that to the GraphReducer
(which in turn requires that all loops are connected to End).
Review URL: https://codereview.chromium.org/1122423003
Cr-Commit-Position: refs/heads/master@{#28251}
Tail calls are matched on the graph, with a dedicated tail call
optimization that is actually testable. The instruction selection can
still fall back to a regular if the platform constraints don't allow to
emit a tail call (i.e. the return locations of caller and callee differ
or the callee takes non-register parameters, which is a restriction that
will be removed in the future).
Also explicitly limit tail call optimization to stubs for now and drop
the global flag.
BUG=v8:4076
LOG=n
Review URL: https://codereview.chromium.org/1114163005
Cr-Commit-Position: refs/heads/master@{#28219}
This prepares for re-landing crrev.com/956373002
This pulls all decision about the snapshot [no|internal|external] into one rule. Previously, this logic was in separate places and not /quite/ the same, which causes build problems.
BUG=
Review URL: https://codereview.chromium.org/1016603004
Cr-Commit-Position: refs/heads/master@{#27523}
This change introduces a liveness analyzer for local variables in frame states.
The main idea is to use the AstGraphBuilder::Environment class to build the control flow graph, and record local variable loads, stores and checkpoints in the CFG basic blocks (LivenessAnalyzerBlock class).
After the graph building finishes, we run a simple data flow analysis over the CFG to figure out liveness of each local variable at each checkpoint. Finally, we run a pass over all the checkpoints and replace dead local variables in the frame states with the 'undefined' value.
Performance numbers for Embenchen are below.
----------- box2d.js
Current --turbo-deoptimization: EmbenchenBox2d(RunTime): 11265 ms.
d8-master --turbo-deoptimization: EmbenchenBox2d(RunTime): 11768 ms.
d8-master: EmbenchenBox2d(RunTime): 10996 ms.
----------- bullet.js
Current --turbo-deoptimization: EmbenchenBullet(RunTime): 17049 ms.
d8-master --turbo-deoptimization: EmbenchenBullet(RunTime): 17384 ms.
d8-master: EmbenchenBullet(RunTime): 16153 ms.
----------- copy.js
Current --turbo-deoptimization: EmbenchenCopy(RunTime): 4877 ms.
d8-master --turbo-deoptimization: EmbenchenCopy(RunTime): 4938 ms.
d8-master: EmbenchenCopy(RunTime): 4940 ms.
----------- corrections.js
Current --turbo-deoptimization: EmbenchenCorrections(RunTime): 7068 ms.
d8-master --turbo-deoptimization: EmbenchenCorrections(RunTime): 6718 ms.
d8-master: EmbenchenCorrections(RunTime): 6858 ms.
----------- fannkuch.js
Current --turbo-deoptimization: EmbenchenFannkuch(RunTime): 4167 ms.
d8-master --turbo-deoptimization: EmbenchenFannkuch(RunTime): 4608 ms.
d8-master: EmbenchenFannkuch(RunTime): 4149 ms.
----------- fasta.js
Current --turbo-deoptimization: EmbenchenFasta(RunTime): 9981 ms.
d8-master --turbo-deoptimization: EmbenchenFasta(RunTime): 9848 ms.
d8-master: EmbenchenFasta(RunTime): 9640 ms.
----------- lua_binarytrees.js
Current --turbo-deoptimization: EmbenchenLuaBinaryTrees(RunTime): 11571 ms.
d8-master --turbo-deoptimization: EmbenchenLuaBinaryTrees(RunTime): 13089 ms.
d8-master: EmbenchenLuaBinaryTrees(RunTime): 10957 ms.
----------- memops.js
Current --turbo-deoptimization: EmbenchenMemOps(RunTime): 7766 ms.
d8-master --turbo-deoptimization: EmbenchenMemOps(RunTime): 7346 ms.
d8-master: EmbenchenMemOps(RunTime): 7738 ms.
----------- primes.js
Current --turbo-deoptimization: EmbenchenPrimes(RunTime): 7459 ms.
d8-master --turbo-deoptimization: EmbenchenPrimes(RunTime): 7453 ms.
d8-master: EmbenchenPrimes(RunTime): 7451 ms.
----------- skinning.js
Current --turbo-deoptimization: EmbenchenSkinning(RunTime): 15564 ms.
d8-master --turbo-deoptimization: EmbenchenSkinning(RunTime): 15611 ms.
d8-master: EmbenchenSkinning(RunTime): 15583 ms.
----------- zlib.js
Current --turbo-deoptimization: EmbenchenZLib(RunTime): 10825 ms.
d8-master --turbo-deoptimization: EmbenchenZLib(RunTime): 11180 ms.
d8-master: EmbenchenZLib(RunTime): 10823 ms.
BUG=
Review URL: https://codereview.chromium.org/949743002
Cr-Commit-Position: refs/heads/master@{#27232}
Instead of the current approach of storing flat vectors in frame states (and possibly reusing the last vector in AST graph builder), this change list builds a tree for the values and tries to reuse the nodes for different frame states. At the moment, we only use this for the local variable part of frame state, but nothing prevents us from using this for all parts.
This change provides two new classes: one for creating the tree (StateValuesCache) and one for iterating the trees (StateValuesAccess).
BUG=
Review URL: https://codereview.chromium.org/1008213002
Cr-Commit-Position: refs/heads/master@{#27222}
This adds a new ControlFlowOptimizer that - for now - recognizes chains
of Branches generated by the SwitchBuilder for a subset of javascript
switches into Switch nodes. Those Switch nodes are then lowered to
either table or lookup switches.
Also rename Case to IfValue (and introduce IfDefault) for consistency.
BUG=v8:3872
LOG=n
Review URL: https://codereview.chromium.org/931623002
Cr-Commit-Position: refs/heads/master@{#26691}
To do so, extract startup_data_util from d8 and use it those executables.
BUG=
Review URL: https://codereview.chromium.org/913703002
Cr-Commit-Position: refs/heads/master@{#26547}
This reverts commit f578d35ba8 because
(immutable) heap numbers are surprisingly mutable in V8. Someone else
might want to cleanup the mess, otherwise we'll just keep it this way.
TBR=jkummerow@chromium.org
BUG=chromium:454894
LOG=y
Review URL: https://codereview.chromium.org/898973003
Cr-Commit-Position: refs/heads/master@{#26447}
Up until now we used a special Terminate node to artifically connect non
terminating loops to the End node, but this was kind of adhoc and didn't
work for the CFG. So without all kinds of weird hacks, the end block in
the CFG will not be connected to NTLs, which makes it impossible to
compute post dominance / control dependence in the current setting.
So instead of Terminate, we add a special Branch to NTLs, whose
condition is the special Always node, which corresponds to True, except
that it cannot be folded away. This way we don't need any special
machinery in the scheduler, since it's just a regular Branch.
R=titzer@chromium.org
Review URL: https://codereview.chromium.org/875263004
Cr-Commit-Position: refs/heads/master@{#26294}
- Make Node::Inputs and Node::Uses mostly STL compliant.
- Get rid of some pre-C++11 crappiness.
- Start moving unit tests from cctest to unittests.
- TrimInputCount() now tries to reserve inputs slots for
later appending.
- Fix numerous style guide violations.
TEST=cctest,unittests
R=dcarney@chromium.org
Review URL: https://codereview.chromium.org/851263002
Cr-Commit-Position: refs/heads/master@{#26098}
The CommonOperatorReducer currently takes care of redundant Phis,
EffectPhis and Selects. This functionality overlaps with ControlReducer,
but is required to make certain optimizations effective, since the
ControlReducer only runs really early and really late in the pipeline
and therefore other reducers aren't reapplied properly after redundant
phi/select elimination.
TEST=unittests
R=hpayer@chromium.org
Review URL: https://codereview.chromium.org/817243003
Cr-Commit-Position: refs/heads/master@{#25922}
This is an initial version of redundant load elimination, currently
limited to LoadField operators, and implemented by walking the effect
chain.
TEST=unittests
R=svenpanne@chromium.org
Review URL: https://codereview.chromium.org/782473002
Cr-Commit-Position: refs/heads/master@{#25673}
