While reading through the jump threading implementation, I noticed
something strange: ApplyForwarding iterates through the block list in
reverse post-order, not in assembly order. Thus, the value prev_fallthru
might not refer to the previous block in assembly order. Obviously it
works fine this way or we would have noticed by now, but I think that
this step would be a little easier to read and reason about if the
iteration used assembly order instead.
I've added a test case to demonstrate the difference when using
assembly order: in a diamond where the right side starts with an empty
deferred block, the current implementation would fail to replace that
block with a nop. I doubt this case would have any real-world impact.
Change-Id: I28abe2043434debb54896871d15c540ad52c6368
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3039261
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76067}
AddImmediate ends up pushing repeated immediates very often
unecessarily. Add support for Int64 immediates being inlined into
InstructionOperand if they fit into the payload (which is almost always
the case). Also add a seperate rpo_immediate vector for RPO numbers to
avoid having to add them to the immediates_ vector multiple times.
Ideally the RPO values would also be inlined, however JumpThreading
needs to patch RPO targets throughout the instruction stream, so we
need an indirection.
Change-Id: I75b1cdb05917f85d4f740a34c3720dd9cf0ee29c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2782282
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73687}
Although the code generator already combines return instructions late
in the pipeline into a common site, there were still superfluous jumps
to that common site left in the code.
Change-Id: I06c885fb0ab6a2c078f9dabdc6616c6881f42c75
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2284984
Commit-Queue: Daniel Clifford <danno@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69133}
Adds support for populating reference maps to the fast
register allocator. In order to calculate whether a stack slot
is live at a given instruction, we use the dominator tree to
build a bitmap of blocks which are dominated by each block.
A variable's spill operand is classed as alive for any blocks that are
dominated by the block it was defined in, until the instruction index
of the spill operand's last use. As such, it may be classified as live
down a branch where the spill operand is never used, however it is safe
since the spill slot won't be re-allocated until after it's last-use
instruction index in any case.
BUG=v8:9684
Change-Id: I772374599ef916f57d82d468f66429e32c712ddf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2298008
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69108}
... by migrating old-style code
MyObject* obj = new (zone) MyObject(...)
to the new style
MyObject* obj = zone->New<MyObject>(...)
Bug: v8:10689
Change-Id: I55c686bbedfa1fd1955a5927df3f72b366312fd4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2288867
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68808}
Cpplint usually checks for non-const reference arguments. They are
forbidden in the style guide, and v8 does not explicitly make an
exception here.
This CL re-enables that warning, and fixes all current violations by
adding an explicit "NOLINT(runtime/references)" comment. In follow-up
CLs, we should aim to remove as many of them as possible.
TBR=mlippautz@chromium.org
Bug: v8:9429
Change-Id: If7054d0b366138b731972ed5d4e304b5ac8423bb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1687891
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62551}
This CL implements an assembly order optimization that moves blocks
that end a loop with an unconditional backedge to the beginning of
the loop, saving a branch.
R=jarin@chromium.org,mstarzinger@chromium.org
BUG=v8:8423
Change-Id: I8a5d25f5472d71227af0f623277ea8d0a8d69867
Reviewed-on: https://chromium-review.googlesource.com/c/1335944
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57572}
This CL splits the backend of TurboFan off into its own directory,
without changing namespaces. This makes ownership management a bit
more fine-grained with a logical separation.
R=mstarzinger@chromium.org,jarin@chromium.org,adamk@chromium.org
Change-Id: I2ac40d6ca2c4f04b8474b630aae0286ecf79ef42
Reviewed-on: https://chromium-review.googlesource.com/c/1308333
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57437}
This CL inserts NOP instructions a little bit earlier into empty
blocks; this ensures that instructions keep their initial position.
Bug: v8:7327
Change-Id: Idee5269f4fd7fc15c44bda83a2be74e8cff62df8
Reviewed-on: https://chromium-review.googlesource.com/1097078
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53672}
This CL fixes all occurences that don't require special OWNER reviews,
or can be reviewed by Michi.
After this one, we should be able to reenable the readability/check
cpplint check.
R=mstarzinger@chromium.org
Bug: v8:6837, v8:6921
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng;master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: Ic81d68d5534eaa795b7197fed5c41ed158361d62
Reviewed-on: https://chromium-review.googlesource.com/721120
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48670}
New code should use nullptr instead of NULL.
This patch updates existing use of NULL to nullptr where applicable,
making the code base more consistent.
BUG=v8:6928,v8:6921
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng;master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: I4687f5b96fcfd88b41fa970a2b937b4f6538777c
Reviewed-on: https://chromium-review.googlesource.com/718338
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48557}
This adds more useful information to the v8-heap-stats tool.
BUG=v8:5489
Review-Url: https://codereview.chromium.org/2394213003
Cr-Commit-Position: refs/heads/master@{#40361}
This is some initial cleanup to keep /src clean. The
AccountingAllocator is actually exclusively used by zones and this
common subfolder makes that more clear.
BUG=v8:5409
Review-Url: https://codereview.chromium.org/2344143003
Cr-Commit-Position: refs/heads/master@{#39558}
We expect that the majority of malloc'd memory held by V8 is allocated
in Zone objects. Introduce an Allocator class that is used by Zones to
manage memory, and allows for querying the current usage.
BUG=none
R=titzer@chromium.org,bmeurer@chromium.org,jarin@chromium.org
LOG=n
TBR=rossberg@chromium.org
Review URL: https://codereview.chromium.org/1847543002
Cr-Commit-Position: refs/heads/master@{#35196}
avoid jump threading erasing the reconstruction of a frame, if the
frame was elided.
BUG=
Review URL: https://codereview.chromium.org/1642823002
Cr-Commit-Position: refs/heads/master@{#33590}
MachineType is now a class with two enum fields:
- MachineRepresentation
- MachineSemantic
Both enums are usable on their own, and this change switches some places from using MachineType to use just MachineRepresentation. Most notably:
- register allocator now uses just the representation.
- Phi and Select nodes only refer to representations.
Review URL: https://codereview.chromium.org/1513543003
Cr-Commit-Position: refs/heads/master@{#32738}
Up until now, if one wanted to specify an explicit stack location or register as an operand for an instruction, it had to also be
explicitly associated with a virtual register as a so-called
FixedRegister or FixedStackSlot.
For the implementation of tail calls, the plan is to use the gap
resolver needs to shuffle stack locations from the caller to the
tail-called callee. In order to do this, it must be possible to
explicitly address operand locations on the stack that are not
associated with virtual registers.
This CL introduces ExplictOperands, which can specify a specific
register or stack location that is not associated with virtual
register. This will allow tail calls to specify the target
locations for the necessary stack moves in the gap for the tail
call without the core register allocation having to know about
the target of the stack moves at all.
In the process this CL:
* creates a new Operand kind, ExplicitOperand, with which
instructions can specify register and stack slots without an
associated virtual register.
* creates a LocationOperand class from which AllocatedOperand and
ExplicitOperand are derived and provides a common interface to
get Register, DoubleRegister and spill slot information.
* removes RegisterOperand, DoubleRegisterOperand,
StackSlotOperand and DoubleStackSlotOperand, they are subsumed
by LocationOperand.
* addresses a cleanup TODO in AllocatedOperand to reduce the
redundancy of AllocatedOperand::Kind by using machine_type() to
determine if an operand corresponds to a general purpose or
double register.
BUG=v8:4076
LOG=n
Review URL: https://codereview.chromium.org/1389373002
Cr-Commit-Position: refs/heads/master@{#31603}
This ensures there is a lazy bailout point at the entry of every
exception handler so that deoptimized code is not re-entered through
caught exceptions.
R=jarin@chromium.org
TEST=cctest/test-run-deopt/DeoptExceptionHandler
Review URL: https://codereview.chromium.org/1173253004
Cr-Commit-Position: refs/heads/master@{#29061}
- allows the optimization of emitted gap move code since the representation of the value in the register is known
- necessary preparation for vector register allocation
- prepare for slot sharing for any value of the same byte width
TBR=jarin@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1111323003
Cr-Commit-Position: refs/heads/master@{#28140}
- allows the optimization of emitted gap move code since the representation of the value in the register is known
- necessary preparation for vector register allocation
- prepare for slot sharing for any value of the same byte width
BUG=
Review URL: https://codereview.chromium.org/1087793002
Cr-Commit-Position: refs/heads/master@{#28137}
- make ParallelMove into a ZoneVector, removing an annoying level of indirection
- make MoveOperands hold InstructionOperands instead of pointers, so there's no more operand aliasing for moves
- opens up possibility of storing MachineType in allocated operands
R=bmeurer@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1081373002
Cr-Commit-Position: refs/heads/master@{#27842}
- ConstantOperand was using a too-small field too store its virtual register
- drop ConvertTo, replace it with simple copy
- split AllocatedOperand off from Immediate and Constant to make assignment clearer, also paving the way for small Immediates
- put zone first in *Operand::New
- driveby: drop delayed ssa deconstruction experiment
R=titzer@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1050803002
Cr-Commit-Position: refs/heads/master@{#27692}
Along the way:
- Thread isolate parameter explicitly through code that used to
rely on getting it from the zone.
- Canonicalize the parameter position of isolate and zone for
affected code
- Change Hydrogen New<> instruction templates to automatically
pass isolate
R=mstarzinger@chromium.org
LOG=N
Review URL: https://codereview.chromium.org/868883002
Cr-Commit-Position: refs/heads/master@{#26252}
