The range of Smis must be reduced so that pointer compression is not lossy.
Smis are kept in sign-extended form. In the future, we might track down all places that perform Smi comparisons or otherwise assume sign-extension. Allowing garbage in the upper half would make it safe to unconditionally add the heap base during pointer decompression.
Based on cf78da8a48.
TEST=ci
Change-Id: If8c76da3166c170618e5b3f3991353bab5c84e6f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/181760
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Liam Appelbe <liama@google.com>
This reverts commit cf78da8a48.
Reason for revert: introduces significant performance regression (~30%) on analyzer benchmarks (warm-analysis) without clearly visible hot-spot.
Original change's description:
> [VM] Reduce Smi size to 32 bit on 64 bit platforms
>
> This reduces small tagged integers on 64 bit platforms from 63 bits to
> 31 bits plus one tag bit.
> This is a step on the way to compile-time-optional compressed pointers
> on 64 bit platforms. See more about this at go/dartvmlearnings
> This causes a slowdown for some uses of integers that don't fit in 31
> signed bits, but because both x64 and ARM64 have unboxed 64 bit
> integers now the performance hit should not be too bad.
>
> This is a reapplication of
> https://dart-review.googlesource.com/c/sdk/+/46244
> It was reverted due to a compilation error on 32 bit
> ARM with DBC.
>
> R=vegorov@google.com
>
> Change-Id: I943de1768519457f0e5a61ef0b4ef204b6a53281
> Reviewed-on: https://dart-review.googlesource.com/51321
> Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
TBR=vegorov@google.com,erikcorry@google.com
# Not skipping CQ checks because original CL landed > 1 day ago.
Change-Id: I8c5b909ec38663b5f5b05f69ef488c97341f8f3d
Reviewed-on: https://dart-review.googlesource.com/54000
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
This reduces small tagged integers on 64 bit platforms from 63 bits to
31 bits plus one tag bit.
This is a step on the way to compile-time-optional compressed pointers
on 64 bit platforms. See more about this at go/dartvmlearnings
This causes a slowdown for some uses of integers that don't fit in 31
signed bits, but because both x64 and ARM64 have unboxed 64 bit
integers now the performance hit should not be too bad.
This is a reapplication of
https://dart-review.googlesource.com/c/sdk/+/46244
It was reverted due to a compilation error on 32 bit
ARM with DBC.
R=vegorov@google.com
Change-Id: I943de1768519457f0e5a61ef0b4ef204b6a53281
Reviewed-on: https://dart-review.googlesource.com/51321
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
This reduces small tagged integers on 64 bit platforms from 63 bits to
31 bits plus one tag bit.
This is a step on the way to compile-time-optional compressed pointers
on 64 bit platforms. See more about this at go/dartvmlearnings
This causes a slowdown for some uses of integers that don't fit in 31
signed bits, but because both x64 and ARM64 have unboxed 64 bit
integers now the performance hit should not be too bad.
This reapplies the change reviewed at
https://dart-review.googlesource.com/c/sdk/+/46244R=kustermann@google.com
Change-Id: I605c21506ec7d4c69fa7049bc419b3ee370685fc
Reviewed-on: https://dart-review.googlesource.com/50202
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Erik Corry <erikcorry@google.com>
This reduces small tagged integers on 64 bit platforms from 63 bits to 31 bits
plus one tag bit.
This is a step on the way to compile-time-optional compressed pointers on 64
bit platforms. See more about this at go/dartvmlearnings
This causes a slowdown for some uses of integers that don't fit in 31 signed
bits, but because both x64 and ARM64 have unboxed 64 bit integers now the
performance hit should not be too bad.
R=kustermann@google.com
Change-Id: I035ed84c29b64f0432cd2d24193eb1c6303c14b0
Reviewed-on: https://dart-review.googlesource.com/46244
Commit-Queue: Erik Corry <erikcorry@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
This CL corrects handling of overflows in range analysis to
account for wrap-around (which happens with new integer semantics).
* If there is an overflow while doing computations in range
analysis, the resulting range is approximated as full int64 range.
* For symbolic range boundaries 'symbol + offset', offset is checked
to stay within [kMinInt64 - kSmiMin, kMaxInt64 - kSmiMax] in order
to guarantee that overflow doesn't occur.
Issue: https://github.com/dart-lang/sdk/issues/31920
Change-Id: I2c16adbe3597e9b718ed2f6ce7210426fcc9e6a6
Reviewed-on: https://dart-review.googlesource.com/39423
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
New folder structure (nested under vm/):
- compiler/
- jit/ - JIT specific code
- aot/ - AOT specific code
- backend/ - all middle-end and back-end code (IL, flow graph)
- assembler/ - assemblers and disassemblers
- frontend/ - front ends (AST -> IL, Kernel -> IL)
compiler/README.md would be the documentation root for the compiler
pipeline
Bug: https://github.com/dart-lang/sdk/issues/30575
Change-Id: I2dfd9688793bff737f7632ddc77fca766875ce36
Reviewed-on: https://dart-review.googlesource.com/2940
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Ryan Macnak