v8/test/unittests/assembler/turbo-assembler-arm64-unittest.cc
Jakob Gruber 7f58ced72e [deoptimizer] Change deopt entries into builtins
While the overall goal of this commit is to change deoptimization
entries into builtins, there are multiple related things happening:

- Deoptimization entries, formerly stubs (i.e. Code objects generated
  at runtime, guaranteed to be immovable), have been converted into
  builtins. The major restriction is that we now need to preserve the
  kRootRegister, which was formerly used on most architectures to pass
  the deoptimization id. The solution differs based on platform.
- Renamed DEOPT_ENTRIES_OR_FOR_TESTING code kind to FOR_TESTING.
- Removed heap/ support for immovable Code generation.
- Removed the DeserializerData class (no longer needed).
- arm64: to preserve 4-byte deopt exits, introduced a new optimization
  in which the final jump to the deoptimization entry is generated
  once per Code object, and deopt exits can continue to emit a
  near-call.
- arm,ia32,x64: change to fixed-size deopt exits. This reduces exit
  sizes by 4/8, 5, and 5 bytes, respectively.

On arm the deopt exit size is reduced from 12 (or 16) bytes to 8 bytes
by using the same strategy as on arm64 (recalc deopt id from return
address). Before:

 e300a002       movw r10, <id>
 e59fc024       ldr ip, [pc, <entry offset>]
 e12fff3c       blx ip

After:

 e59acb35       ldr ip, [r10, <entry offset>]
 e12fff3c       blx ip

On arm64 the deopt exit size remains 4 bytes (or 8 bytes in same cases
with CFI). Additionally, up to 4 builtin jumps are emitted per Code
object (max 32 bytes added overhead per Code object). Before:

 9401cdae       bl <entry offset>

After:

 # eager deoptimization entry jump.
 f95b1f50       ldr x16, [x26, <eager entry offset>]
 d61f0200       br x16
 # lazy deoptimization entry jump.
 f95b2b50       ldr x16, [x26, <lazy entry offset>]
 d61f0200       br x16
 # the deopt exit.
 97fffffc       bl <eager deoptimization entry jump offset>

On ia32 the deopt exit size is reduced from 10 to 5 bytes. Before:

 bb00000000     mov ebx,<id>
 e825f5372b     call <entry>

After:

 e8ea2256ba     call <entry>

On x64 the deopt exit size is reduced from 12 to 7 bytes. Before:

 49c7c511000000 REX.W movq r13,<id>
 e8ea2f0700     call <entry>

After:

 41ff9560360000 call [r13+<entry offset>]

Bug: v8:8661,v8:8768
Change-Id: I13e30aedc360474dc818fecc528ce87c3bfeed42
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2465834
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70597}
2020-10-19 07:32:48 +00:00

197 lines
6.2 KiB
C++

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/codegen/arm64/macro-assembler-arm64-inl.h"
#include "src/codegen/macro-assembler.h"
#include "src/execution/simulator.h"
#include "src/utils/ostreams.h"
#include "test/common/assembler-tester.h"
#include "test/unittests/test-utils.h"
#include "testing/gtest-support.h"
namespace v8 {
namespace internal {
#define __ tasm.
// If we are running on android and the output is not redirected (i.e. ends up
// in the android log) then we cannot find the error message in the output. This
// macro just returns the empty string in that case.
#if defined(ANDROID) && !defined(V8_ANDROID_LOG_STDOUT)
#define ERROR_MESSAGE(msg) ""
#else
#define ERROR_MESSAGE(msg) msg
#endif
// Test the x64 assembler by compiling some simple functions into
// a buffer and executing them. These tests do not initialize the
// V8 library, create a context, or use any V8 objects.
class TurboAssemblerTest : public TestWithIsolate {};
TEST_F(TurboAssemblerTest, TestHardAbort) {
auto buffer = AllocateAssemblerBuffer();
TurboAssembler tasm(isolate(), AssemblerOptions{}, CodeObjectRequired::kNo,
buffer->CreateView());
__ set_root_array_available(false);
__ set_abort_hard(true);
__ CodeEntry();
__ Abort(AbortReason::kNoReason);
CodeDesc desc;
tasm.GetCode(isolate(), &desc);
buffer->MakeExecutable();
// We need an isolate here to execute in the simulator.
auto f = GeneratedCode<void>::FromBuffer(isolate(), buffer->start());
ASSERT_DEATH_IF_SUPPORTED({ f.Call(); }, ERROR_MESSAGE("abort: no reason"));
}
TEST_F(TurboAssemblerTest, TestCheck) {
auto buffer = AllocateAssemblerBuffer();
TurboAssembler tasm(isolate(), AssemblerOptions{}, CodeObjectRequired::kNo,
buffer->CreateView());
__ set_root_array_available(false);
__ set_abort_hard(true);
__ CodeEntry();
// Fail if the first parameter is 17.
__ Mov(w1, Immediate(17));
__ Cmp(w0, w1); // 1st parameter is in {w0}.
__ Check(Condition::ne, AbortReason::kNoReason);
__ Ret();
CodeDesc desc;
tasm.GetCode(isolate(), &desc);
buffer->MakeExecutable();
// We need an isolate here to execute in the simulator.
auto f = GeneratedCode<void, int>::FromBuffer(isolate(), buffer->start());
f.Call(0);
f.Call(18);
ASSERT_DEATH_IF_SUPPORTED({ f.Call(17); }, ERROR_MESSAGE("abort: no reason"));
}
struct MoveObjectAndSlotTestCase {
const char* comment;
Register dst_object;
Register dst_slot;
Register object;
Register offset_register = no_reg;
};
const MoveObjectAndSlotTestCase kMoveObjectAndSlotTestCases[] = {
{"no overlap", x0, x1, x2},
{"no overlap", x0, x1, x2, x3},
{"object == dst_object", x2, x1, x2},
{"object == dst_object", x2, x1, x2, x3},
{"object == dst_slot", x1, x2, x2},
{"object == dst_slot", x1, x2, x2, x3},
{"offset == dst_object", x0, x1, x2, x0},
{"offset == dst_object && object == dst_slot", x0, x1, x1, x0},
{"offset == dst_slot", x0, x1, x2, x1},
{"offset == dst_slot && object == dst_object", x0, x1, x0, x1}};
// Make sure we include offsets that cannot be encoded in an add instruction.
const int kOffsets[] = {0, 42, kMaxRegularHeapObjectSize, 0x101001};
template <typename T>
class TurboAssemblerTestWithParam : public TurboAssemblerTest,
public ::testing::WithParamInterface<T> {};
using TurboAssemblerTestMoveObjectAndSlot =
TurboAssemblerTestWithParam<MoveObjectAndSlotTestCase>;
TEST_P(TurboAssemblerTestMoveObjectAndSlot, MoveObjectAndSlot) {
const MoveObjectAndSlotTestCase test_case = GetParam();
TRACED_FOREACH(int32_t, offset, kOffsets) {
auto buffer = AllocateAssemblerBuffer();
TurboAssembler tasm(nullptr, AssemblerOptions{}, CodeObjectRequired::kNo,
buffer->CreateView());
__ CodeEntry();
__ Push(x0, padreg);
__ Mov(test_case.object, x1);
Register src_object = test_case.object;
Register dst_object = test_case.dst_object;
Register dst_slot = test_case.dst_slot;
Operand offset_operand(0);
if (test_case.offset_register == no_reg) {
offset_operand = Operand(offset);
} else {
__ Mov(test_case.offset_register, Operand(offset));
offset_operand = Operand(test_case.offset_register);
}
std::stringstream comment;
comment << "-- " << test_case.comment << ": MoveObjectAndSlot("
<< dst_object << ", " << dst_slot << ", " << src_object << ", ";
if (test_case.offset_register == no_reg) {
comment << "#" << offset;
} else {
comment << test_case.offset_register;
}
comment << ") --";
__ RecordComment(comment.str().c_str());
__ MoveObjectAndSlot(dst_object, dst_slot, src_object, offset_operand);
__ RecordComment("--");
// The `result` pointer was saved on the stack.
UseScratchRegisterScope temps(&tasm);
Register scratch = temps.AcquireX();
__ Pop(padreg, scratch);
__ Str(dst_object, MemOperand(scratch));
__ Str(dst_slot, MemOperand(scratch, kSystemPointerSize));
__ Ret();
CodeDesc desc;
tasm.GetCode(nullptr, &desc);
if (FLAG_print_code) {
Handle<Code> code =
Factory::CodeBuilder(isolate(), desc, CodeKind::FOR_TESTING).Build();
StdoutStream os;
code->Print(os);
}
buffer->MakeExecutable();
// We need an isolate here to execute in the simulator.
auto f = GeneratedCode<void, byte**, byte*>::FromBuffer(isolate(),
buffer->start());
byte* object = new byte[offset];
byte* result[] = {nullptr, nullptr};
f.Call(result, object);
// The first element must be the address of the object, and the second the
// slot addressed by `offset`.
EXPECT_EQ(result[0], &object[0]);
EXPECT_EQ(result[1], &object[offset]);
delete[] object;
}
}
INSTANTIATE_TEST_SUITE_P(TurboAssemblerTest,
TurboAssemblerTestMoveObjectAndSlot,
::testing::ValuesIn(kMoveObjectAndSlotTestCases));
#undef __
#undef ERROR_MESSAGE
} // namespace internal
} // namespace v8