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  1. 20 Sep, 2018 1 commit
  3. 20 Aug, 2018 1 commit
  5. 03 Jul, 2018 1 commit
  7. 25 May, 2018 1 commit
    • jgruber's avatar
      [builtins,x64] pc-relative builtin-to-builtin calls · e5630ea9
      jgruber authored 
      This addresses one of the major remaining slowdowns with embedded
builtins on x64.

When generating code for a call to a builtin callee from a builtin
caller, we'd look up the Code target object from the builtins constant
list, calculate the location of the first instruction, and jump to it.
Note that for embedded builtin callees, the Code object is itself only
a trampoline to the off-heap code and thus an additional indirection.
An example of the call sequence in pseudo-asm:

// Load from the constants list.
mov reg, [kRootPointer, kBuiltinsConstantListOffset]
mov reg, [reg, offset_of_the_code_constant]
// Calculate first instruction and call it.
add reg, Code::kHeaderOffset
call reg
// The trampoline forwards to the off-heap area.
mov kOffHeapTrampolineRegister, <off-heap instruction_start>
jmp kOffHeapTrampolineRegister

This CL changes calls to embedded builtin targets to use pc-relative
addressing. This reduces the above instruction sequence to:

call <pc-relative offset to target instruction_start>

Embedded-to-embedded calls jump directly to the embedded instruction
stream, bypassing the trampoline. Heap-to-embedded calls (and all
calls to heap-builtins) use pc-relative addressing targeting the
on-heap Code object.

Other relevant platforms (arm,arm64,mips,mips64) do not use pc-relative
calls. For these, we'll need a different solution, e.g. a table of
embedded builtin addresses reachable from the root pointer, similar to
the external reference table.

Bug: v8:6666
Change-Id: Ic0317d454e2da37d74eaecebcdfcbc0d5f5041ad
Reviewed-on: https://chromium-review.googlesource.com/1068732
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53349}
      e5630ea9
  9. 07 May, 2018 1 commit
    • jgruber's avatar
      [builtins] Convert CEntry/GetProperty/StringAdd stubs to builtins · d8131cd6
      jgruber authored 
      Stubs and builtins are very similar. The main differences are that
stubs can be parameterized and may be generated at runtime, whereas
builtins are generated at mksnapshot-time and shipped with the snapshot
(or embedded into the binary).

My main motivation for these conversions is that we can generate
faster calls and jumps to (embedded) builtins callees from (embedded)
builtin callers. Instead of going through the builtins constants table
indirection, we can simply do a pc-relative call/jump.

This also unlocks other refactorings, e.g. removal of
CallRuntimeDelayed.

TBR=mlippautz@chromium.org

Bug: v8:6666
Change-Id: I4cd63477f19a330ec70bbf20e2af8a42fb05fabb
Reviewed-on: https://chromium-review.googlesource.com/1044245Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53027}
      d8131cd6
  11. 02 May, 2018 1 commit
    • jgruber's avatar
      Reland: [builtins] Patch self-references in constants table · ab9e0124
      jgruber authored 
      Original CL: https://crrev.com/c/1018468

During code generation, we generate self-references (i.e. references to
the Code object currently being generated) as references to a temporary
handle. When the final Code object has been allocated, the handle's
location is fixed up and RelocInfo iteration fixes up all references
embedded in the generated code.

This adds support for this mechanism to the builtins constants table
builder. CodeObject() is now a new handle pointing to a dedicated
self-reference marker in order to distinguish between self-references
and references to undefined. In Factory::NewCode, we patch up
the constants table.

TBR=yangguo@chromium.org,mlippautz@chromium.org

Bug: v8:6666
Change-Id: I3fa422c57de99c9851dc7a86394a8387c7c2b397
Reviewed-on: https://chromium-review.googlesource.com/1039366
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52916}
      ab9e0124
  13. 27 Apr, 2018 2 commits
    • Michael Achenbach's avatar
      Revert "[builtins] Patch self-references in constants table" · 77d90890
      Michael Achenbach authored 
      This reverts commit 6379e2a4.

Reason for revert:
https://logs.chromium.org/v/?s=chromium%2Fbb%2Fclient.v8%2FV8_Win64%2F23855%2F%2B%2Frecipes%2Fsteps%2FCheck%2F0%2Flogs%2Fmkgrokdump%2F0

Original change's description:
> [builtins] Patch self-references in constants table
> 
> During code generation, we generate self-references (i.e. references to
> the Code object currently being generated) as references to a temporary
> handle. When the final Code object has been allocated, the handle's
> location is fixed up and RelocInfo iteration fixes up all references
> embedded in the generated code.
> 
> This adds support for this mechanism to the builtins constants table
> builder. CodeObject() is now a new handle pointing to a dedicated
> self-reference marker in order to distinguish between self-references
> and references to undefined. In Factory::NewCode, we patch up
> the constants table.
> 
> Bug: v8:6666
> Change-Id: If74ed91bb1c3b8abb20ff2f0a87d1bcd9a1b0511
> Reviewed-on: https://chromium-review.googlesource.com/1018468
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52854}

TBR=yangguo@chromium.org,mlippautz@chromium.org,jgruber@chromium.org

Change-Id: I8cf8c4b43f51285ea913c6c8fdd339bd9ea645df
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6666
Reviewed-on: https://chromium-review.googlesource.com/1033092Reviewed-by: 's avatarMichael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52856}
      77d90890
    • jgruber's avatar
      [builtins] Patch self-references in constants table · 6379e2a4
      jgruber authored 
      During code generation, we generate self-references (i.e. references to
the Code object currently being generated) as references to a temporary
handle. When the final Code object has been allocated, the handle's
location is fixed up and RelocInfo iteration fixes up all references
embedded in the generated code.

This adds support for this mechanism to the builtins constants table
builder. CodeObject() is now a new handle pointing to a dedicated
self-reference marker in order to distinguish between self-references
and references to undefined. In Factory::NewCode, we patch up
the constants table.

Bug: v8:6666
Change-Id: If74ed91bb1c3b8abb20ff2f0a87d1bcd9a1b0511
Reviewed-on: https://chromium-review.googlesource.com/1018468
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarMichael Lippautz <mlippautz@chromium.org>
Reviewed-by: 's avatarYang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52854}
      6379e2a4
  15. 22 Mar, 2018 1 commit
    • jgruber's avatar
      Reland "[builtins] Load external references from the external-reference-table" · 0031724f
      jgruber authored 
      This is a reland of 9afde91b

Original change's description:
> [builtins] Load external references from the external-reference-table
>
> Off-heap code cannot embed external references. With this CL, we load
> from the external reference table (reached through the root pointer)
> instead.
>
> In a follow-up, the table could be stored within the isolate itself,
> removing one more level of indirection.
>
> Bug: v8:6666
> Change-Id: I4c612ad3d4112ec03c3b389f5bfb9cdc3dc8a671
> Reviewed-on: https://chromium-review.googlesource.com/970468
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52073}

TBR=mstarzinger@chromium.org

Bug: v8:6666, v8:7580
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I30639fe17ea345119d38a176a29d521c4b1904cb
Reviewed-on: https://chromium-review.googlesource.com/975241
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarMichael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52141}
      0031724f
  17. 21 Mar, 2018 2 commits
    • Jakob Gruber's avatar
      Revert "Reland "[builtins] Load external references from the external-reference-table"" · 8aa3a373
      Jakob Gruber authored 
      This reverts commit f8184738.

Reason for revert: arm is still unhappy https://build.chromium.org/p/client.v8.ports/builders/V8%20Arm%20GC%20Stress/builds/6633

Original change's description:
> Reland "[builtins] Load external references from the external-reference-table"
> 
> This is a reland of 9afde91b
> 
> Original change's description:
> > [builtins] Load external references from the external-reference-table
> >
> > Off-heap code cannot embed external references. With this CL, we load
> > from the external reference table (reached through the root pointer)
> > instead.
> >
> > In a follow-up, the table could be stored within the isolate itself,
> > removing one more level of indirection.
> >
> > Bug: v8:6666
> > Change-Id: I4c612ad3d4112ec03c3b389f5bfb9cdc3dc8a671
> > Reviewed-on: https://chromium-review.googlesource.com/970468
> > Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> > Reviewed-by: Yang Guo <yangguo@chromium.org>
> > Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#52073}
> 
> TBR=mstarzinger@chromium.org
> 
> Bug: v8:6666, v8:7580
> Change-Id: I163cfc15605c1183b79ead77df0e37d71d60b6f7
> Reviewed-on: https://chromium-review.googlesource.com/972821
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52118}

TBR=yangguo@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org

Change-Id: I5bcd1a1c84c6e9a6a24364390c9359d43c77120d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6666, v8:7580
Reviewed-on: https://chromium-review.googlesource.com/973782Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52121}
      8aa3a373
    • jgruber's avatar
      Reland "[builtins] Load external references from the external-reference-table" · f8184738
      jgruber authored 
      This is a reland of 9afde91b

Original change's description:
> [builtins] Load external references from the external-reference-table
>
> Off-heap code cannot embed external references. With this CL, we load
> from the external reference table (reached through the root pointer)
> instead.
>
> In a follow-up, the table could be stored within the isolate itself,
> removing one more level of indirection.
>
> Bug: v8:6666
> Change-Id: I4c612ad3d4112ec03c3b389f5bfb9cdc3dc8a671
> Reviewed-on: https://chromium-review.googlesource.com/970468
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52073}

TBR=mstarzinger@chromium.org

Bug: v8:6666, v8:7580
Change-Id: I163cfc15605c1183b79ead77df0e37d71d60b6f7
Reviewed-on: https://chromium-review.googlesource.com/972821
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52118}
      f8184738
  19. 20 Mar, 2018 2 commits
  21. 05 Mar, 2018 1 commit
  23. 01 Mar, 2018 1 commit
  25. 23 Feb, 2018 1 commit
  27. 21 Feb, 2018 1 commit
    • jgruber's avatar
      [builtins] Add builtins constants list to roots · ad74be52
      jgruber authored 
      This is a step towards off-heap (and eventually isolate-independent)
builtins.

Off-heap code cannot use the standard CallStub/CallRuntime mechanisms,
since they directly embed the callee code object pointer within the
caller.  There are two main issues with that: 1. the callee may be
moved by GC, and 2. the pc-relative addressing we currently use breaks
(i.e. ends up pointing to a random spot on the heap) when moving the
caller off-heap.

This CL addresses that by introducing a constants list stored on the
roots array.  Instead of embedding code targets, we now have the option
of loading them from constants list. The code sequence is:

REX.W movq rax,[r13+0x4a0]  // Load the constants cache.
REX.W movq rdx,[rax+0xf]    // From there, load the code target.
...
REX.W addq rdx,0x5f         // Add instruction_start.
call rdx

There's no visible performance impact on the web tooling benchmark.

This list will later be extended to also contain other constants such
as Strings.

Bug: v8:6666
Change-Id: Ifcf67d1f682804ba0b6d3d0383216e16575b6bf5
Reviewed-on: https://chromium-review.googlesource.com/923729
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Reviewed-by: 's avatarRoss McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51434}
      ad74be52