On x64, we allocate one big code region such that we can use near jumps
and near calls. The jump table did not make use of that design yet.
This CL changes that by emitting jump table slots as near jumps. This
also speeds up patching jump table slots significantly, since far jumps
populate the inline constant pool, which is unneeded overhead in this
case.
As a drive-by, this CL cleans up the API of near_call and near_jmp. The
current semantics is broken, and only works because this is only used
for WebAssembly calls which are patched anyway after code generation.
Also, x64 now uses the same path in test-jump-table-assembler.cc as
arm64 to ensure that all targets are within near-call-distance.
R=mstarzinger@chromium.org
Bug: v8:8916
Change-Id: Iffc34e248b72167307ffdab62dd2212c4ae86a32
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1561313
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60777}
This extends the "test-jump-table-assembler" stress test to supported
architectures. Note that on both PPC and S390 the tests flushes out the
race during jump table patching pretty reliably. Fixing this issue is
outside the scope of this change, this just ensures test coverage exists
but keeps the test in question disabled.
R=clemensh@chromium.org
TEST=cctest/test-jump-table-assembler
BUG=v8:8018
Change-Id: Ia299ed2a42f9858019627270a25026b53f3628d3
Reviewed-on: https://chromium-review.googlesource.com/c/1478200
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59738}
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}
The test was flaky because it assumed that AllocatedAssemblerBuffer
would eventually return an address within near-call range. Rarely, this
did not happen (within the retry limit), and so the test would crash.
This fix allocates a single, kMaxWasmCodeMemory-sized buffer for the
test, and generates call sequences within that buffer.
BUG=v8:8245
Change-Id: I4b44d897c6cbda15a18ab992fa57805de3b2db29
Reviewed-on: https://chromium-review.googlesource.com/c/1347484
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Jacob Bramley <jacob.bramley@arm.com>
Cr-Commit-Position: refs/heads/master@{#57898}
This is the port of concurrent jump table patching support to ARM. It
extends the corresponding stress test and changes the encoding of code
targets in jump table slots to use constant pool entries.
R=clemensh@chromium.org
TEST=cctest/test-jump-table-assembler
BUG=v8:8018
Change-Id: I4b709a7f14dace0f4eb9219f995d42ca607bb25f
Reviewed-on: https://chromium-review.googlesource.com/1164952
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54971}
This adds initial support for concurrently patching jump table slots. It
is needed once different Isolates share code (for the --wasm-shared-code
feature). We need to ensure that instructions holding the target address
within a jump table slot do not cross cache-line boundaries. To do this,
the jump table has been split into consecutive pages.
Note that this also adds a stress test for multiple threads hammering at
a single slot concurrently. The test is currently limited to the ia32
and the x64 architecture, but will be extended to cover others. The test
reliably triggers tearing of the target address on almost every run of
the test and hence serves to prevent regressions.
R=clemensh@chromium.org
TEST=cctest/test-jump-table-assembler
BUG=v8:8018
Change-Id: Ife56bbb61ffcae5d8906ca7b8c604b195603707c
Reviewed-on: https://chromium-review.googlesource.com/1163664
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54942}
