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  1. 31 Aug, 2015 1 commit
    • mstarzinger's avatar
      [turbofan] Remove usage of Unique<T> from graph. · 6e65e6db
      mstarzinger authored 
      The usage of Unique<T> throughout the TurboFan IR does not have any
advantage. There is no single point in time when they are initialized
and most use-sites looked through to the underlying Handle<T> anyways.
Also there already was a mixture of Handle<T> versus Unique<T> in the
graph and this unifies the situation to use Handle<T> everywhere.

R=bmeurer@chromium.org,titzer@chromium.org

Review URL: https://codereview.chromium.org/1314473007

Cr-Commit-Position: refs/heads/master@{#30458}
      6e65e6db
  3. 20 Jul, 2015 1 commit
    • danno's avatar
      [turbofan]: Add a context relaxation Reducer · cca5e74a
      danno authored 
      In many cases, the context that TurboFan's ASTGraphBuilder or subsequent
reduction operations attaches to nodes does not need to be that exact
context, but rather only needs to be one with the same native context,
because it is used internally only to fetch the native context, e.g. for
creating and throwing exceptions.

This reducer recognizes common cases where the context that is specified
for a node can be relaxed to a canonical, less specific one. This
relaxed context can either be the enclosing function's context or a specific
Module or Script context that is explicitly created within the function.

This optimization is especially important for TurboFan-generated code stubs
which use context specialization and inlining to generate optimal code.
Without context relaxation, many extraneous moves are generated to pass
exactly the right context to internal functions like ToNumber and
AllocateHeapNumber, which only need the native context. By turning context
relaxation on, these moves disappear because all these common internal
context uses are unified to the context passed into the stub function, which
is typically already in the correct context register and remains there for
short stubs. It also eliminates the explicit use of a specialized context
constant in the code stub in these cases, which could cause memory leaks.

Review URL: https://codereview.chromium.org/1244583003

Cr-Commit-Position: refs/heads/master@{#29763}
      cca5e74a
  5. 06 Jul, 2015 1 commit
  7. 26 Jun, 2015 1 commit
  9. 23 Jun, 2015 1 commit
  11. 19 Jun, 2015 1 commit
    • bmeurer's avatar
      [turbofan] Proper dead code elimination as regular reducer. · 733a2463
      bmeurer authored 
      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}
      733a2463
  13. 18 Jun, 2015 1 commit
  15. 28 May, 2015 2 commits
  17. 26 May, 2015 1 commit
  19. 15 May, 2015 1 commit
  21. 11 May, 2015 1 commit
  23. 06 May, 2015 1 commit
  25. 05 May, 2015 1 commit
    • bmeurer's avatar
      [turbofan] Fix tail call optimization. · d21de2a4
      bmeurer authored 
      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}
      d21de2a4
  27. 22 Apr, 2015 1 commit
  29. 20 Apr, 2015 1 commit
  31. 19 Mar, 2015 1 commit
    • jarin's avatar
      [turbofan] Remember types for deoptimization during simplified lowering. · b7dc9c58
      jarin authored 
      With this change, we remember the types of frame state inputs (in a new
operator, called TypedStateValues). Instead of inferring the value types
when building translations, we used the recorded types.

The original approach was not reliable because the passes after
simplified lowering can change node types, and this in turn confuses
the translation builder.

BUG=chromium:468727
LOG=n
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1015423002

Cr-Commit-Position: refs/heads/master@{#27310}
      b7dc9c58
  33. 18 Mar, 2015 1 commit
  35. 04 Mar, 2015 1 commit
  37. 20 Feb, 2015 1 commit
  39. 17 Feb, 2015 1 commit
    • bmeurer's avatar
      [turbofan] Optimize certain chains of Branch into a Switch. · acd9c46c
      bmeurer authored 
      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}
      acd9c46c
  41. 09 Feb, 2015 1 commit
  43. 27 Jan, 2015 1 commit
    • bmeurer's avatar
      [turbofan] Ensure that NTLs are always properly connected to the end. · 59a02ebd
      bmeurer authored 
      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}
      59a02ebd
  45. 20 Jan, 2015 1 commit
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  55. 27 Oct, 2014 1 commit
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  59. 22 Oct, 2014 2 commits
  61. 07 Oct, 2014 1 commit
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  65. 30 Sep, 2014 1 commit
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  71. 18 Sep, 2014 1 commit
  73. 17 Sep, 2014 1 commit