Commit Graph

6 Commits

Author SHA1 Message Date
Pierre Langlois
3f1a59f47f [arm][arm64] Do not allocate temp registers for the write barrier.
Improve code generation for stores with write barriers slightly by using the
assembler's dedicated scratch registers (x16 and x17 on Arm64, ip on Arm)
instead of allocating temporaries.

To do this, we've done two things:

  - Use ip as a scratch register when loading page flags.

  - TurboAssembler::CallRecordWriteStub() now takes the offset of the slot
    that's written to rather than its address, removing the need to allocate a
    temporary register for it.

In essence, we've gone from:

```
;; Do the store.
stur x19, [x9, #15]
;; Check *destination* object page flags and jump out-of-line.
and x4, x9, #0xfffffffffff80000
ldr x4, [x4, #8]
tbnz x4, #2, #+0x1e7c
|     ;; Check *source* object page flags.
| `-> and x4, x19, #0xfffffffffff80000
|     ldr x4, [xM, #8]
|,--- tbz x4, #1, #-0x1e80
|     ;; Compute address of slot.
|     add x5, x9, #0xf (15)
|     ;; Setup arguments to RecordWrite
|     stp x2, x3, [sp, #-32]!
|     stp x4, lr, [sp, #16]
|     stp x0, x1, [sp, #-16]!
|     mov x0, x9 ;; Object address in x9
|     mov x1, x5 ;; Slot address in x5
|     movz x2, #0x0
|     movz x3, #0x100000000
|     ;; Call RecordWrite
|     ldr x16, pc+2056
|     blr x16
```

Which allocates x4 and x5 as temporaries.

To:

```
stur x19, [x9, #15]
and x16, x9, #0xfffffffffff80000 ;; Using x16 instead of allocating x4.
ldr x16, [x16, #8]
tbnz x16, #2, #+0x1e7c
| `-> and x16, x19, #0xfffffffffff80000
|     ldr x16, [xM, #8]
|,--- tbz x16, #1, #-0x1e80
|     stp x2, x3, [sp, #-32]!
|     stp x4, lr, [sp, #16]
|     stp x0, x1, [sp, #-16]!
|     mov x0, x9            ;; Object address still in x9.
|     add x1, x9, #0xf (15) ;; Compute the slot address directly.
|     movz x2, #0x0
|     movz x3, #0x100000000
|     ldr x16, pc+2056
|     blr x16
```

Finally, `RecordWriteField()` does not need an extra scratch register anymore.

Change-Id: Icb71310e7b8ab1ca83ced250851456166b337d00
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1505793
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61153}
2019-05-02 11:19:00 +00:00
Clemens Hammacher
1a1f4e1ef4 [test] Refactor AllocateAssemblerBuffer
Refactor the AllocateAssemblerBuffer helper for the new Assembler API.
This is the only non-mechanical part, all other callsites that create
Assembler instances can be trivially changed to the new API. This will
be done in a separate CL.

R=mstarzinger@chromium.org

Bug: v8:8689, v8:8562
Change-Id: I6c150748eeea778d9b70f41fd66fbb1221035a1b
Reviewed-on: https://chromium-review.googlesource.com/c/1415490
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58881}
2019-01-17 11:57:07 +00:00
Clemens Hammacher
91ab657e36 Enable TurboAssembler tests on native android
We currently don't execute the tests on android, because the error
message is redirected to the android log. What we can still to though
is ensuring that the call aborts the process, but just ignore the error
message.

R=mstarzinger@chromium.org

Bug: chromium:863799
Change-Id: I54b503849358133ffe647be83eae7a964c2ac49e
Reviewed-on: https://chromium-review.googlesource.com/1148444
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54839}
2018-08-01 12:20:17 +00:00
Clemens Hammacher
d324382e1c Reland "[turboassembler] Introduce hard-abort mode"
This is a reland of a462a7854a

Original change's description:
> [turboassembler] Introduce hard-abort mode
> 
> For checks and assertions (mostly for debug code, like stack alignment
> or zero extension), we had two modes: Emit a call to the {Abort}
> runtime function (the default), and emit a debug break (used for
> testing, enabled via --trap-on-abort).
> In wasm, where we cannot just call a runtime function because code must
> be isolate independent, we always used the trap-on-abort behaviour.
> This causes problems for our fuzzers, which do not catch SIGTRAP, and
> hence do not detect debug code failures.
> 
> This CL introduces a third mode ("hard abort"), which calls a C
> function via {ExternalReference}. The C function still outputs the
> abort reason, but does not print the stack trace. It then aborts via
> "OS::Abort", just like the runtime function.
> This will allow fuzzers to detect the crash and even find a nice error
> message.
> 
> Even though this looks like a lot of code churn, it is actually not.
> Most added lines are new tests, and other changes are minimal.
> 
> R=mstarzinger@chromium.org
> 
> Bug: chromium:863799
> Change-Id: I77c58ff72db552d49014614436259ccfb49ba87b
> Reviewed-on: https://chromium-review.googlesource.com/1142163
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54592}

Bug: chromium:863799
Change-Id: I7729a47b4823a982a8e201df36520aa2b6ef5326
Reviewed-on: https://chromium-review.googlesource.com/1146100
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54656}
2018-07-24 15:58:46 +00:00
Sigurd Schneider
039c18e19a Speculatively revert "[turboassembler] Introduce hard-abort mode"
This reverts commit a462a7854a.

Reason for revert: Breaks a TurboAssembler test:
https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Arm/7726

Original change's description:
> [turboassembler] Introduce hard-abort mode
> 
> For checks and assertions (mostly for debug code, like stack alignment
> or zero extension), we had two modes: Emit a call to the {Abort}
> runtime function (the default), and emit a debug break (used for
> testing, enabled via --trap-on-abort).
> In wasm, where we cannot just call a runtime function because code must
> be isolate independent, we always used the trap-on-abort behaviour.
> This causes problems for our fuzzers, which do not catch SIGTRAP, and
> hence do not detect debug code failures.
> 
> This CL introduces a third mode ("hard abort"), which calls a C
> function via {ExternalReference}. The C function still outputs the
> abort reason, but does not print the stack trace. It then aborts via
> "OS::Abort", just like the runtime function.
> This will allow fuzzers to detect the crash and even find a nice error
> message.
> 
> Even though this looks like a lot of code churn, it is actually not.
> Most added lines are new tests, and other changes are minimal.
> 
> R=​mstarzinger@chromium.org
> 
> Bug: chromium:863799
> Change-Id: I77c58ff72db552d49014614436259ccfb49ba87b
> Reviewed-on: https://chromium-review.googlesource.com/1142163
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54592}

TBR=mstarzinger@chromium.org,clemensh@chromium.org

Change-Id: I60c011cfe262ccebbb9abf32699a9fe17e72a3c8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:863799
Reviewed-on: https://chromium-review.googlesource.com/1145431
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54597}
2018-07-20 17:28:49 +00:00
Clemens Hammacher
a462a7854a [turboassembler] Introduce hard-abort mode
For checks and assertions (mostly for debug code, like stack alignment
or zero extension), we had two modes: Emit a call to the {Abort}
runtime function (the default), and emit a debug break (used for
testing, enabled via --trap-on-abort).
In wasm, where we cannot just call a runtime function because code must
be isolate independent, we always used the trap-on-abort behaviour.
This causes problems for our fuzzers, which do not catch SIGTRAP, and
hence do not detect debug code failures.

This CL introduces a third mode ("hard abort"), which calls a C
function via {ExternalReference}. The C function still outputs the
abort reason, but does not print the stack trace. It then aborts via
"OS::Abort", just like the runtime function.
This will allow fuzzers to detect the crash and even find a nice error
message.

Even though this looks like a lot of code churn, it is actually not.
Most added lines are new tests, and other changes are minimal.

R=mstarzinger@chromium.org

Bug: chromium:863799
Change-Id: I77c58ff72db552d49014614436259ccfb49ba87b
Reviewed-on: https://chromium-review.googlesource.com/1142163
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54592}
2018-07-20 14:44:29 +00:00