test-jump-table-assembler.cc | Explore in Territory

// 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 <bitset>

#include "src/base/utils/random-number-generator.h"
#include "src/codegen/assembler-inl.h"
#include "src/codegen/macro-assembler-inl.h"
#include "src/execution/simulator.h"
#include "src/utils/utils.h"
#include "src/wasm/code-space-access.h"
#include "src/wasm/jump-table-assembler.h"
#include "test/cctest/cctest.h"
#include "test/common/assembler-tester.h"

namespace v8 {
namespace internal {
namespace wasm {

#if 0
#define TRACE …
#else
#define TRACE …
#endif

#define __ …

namespace {

static volatile int global_stop_bit = …;

constexpr int kJumpTableSlotCount = …;
constexpr uint32_t kJumpTableSize = …;

// This must be a safe commit page size so we pick the largest OS page size that
// V8 is known to support. Arm64 linux can support up to 64k at runtime.
constexpr size_t kThunkBufferSize = …;

#if V8_TARGET_ARCH_ARM64 || V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_LOONG64
// We need the branches (from CompileJumpTableThunk) to be within near-call
// range of the jump table slots. The address hint to AllocateAssemblerBuffer
// is not reliable enough to guarantee that we can always achieve this with
// separate allocations, so we generate all code in a single
// kMaxCodeMemory-sized chunk.
constexpr size_t kAssemblerBufferSize = …;
constexpr uint32_t kAvailableBufferSlots = …;
constexpr uint32_t kBufferSlotStartOffset = …;
#else
constexpr size_t kAssemblerBufferSize = kJumpTableSize;
constexpr uint32_t kAvailableBufferSlots = 0;
constexpr uint32_t kBufferSlotStartOffset = 0;
#endif

Address AllocateJumpTableThunk(
    Address jump_target, uint8_t* thunk_slot_buffer,
    std::bitset<kAvailableBufferSlots>* used_slots,
    std::vector<std::unique_ptr<TestingAssemblerBuffer>>* thunk_buffers) { … }

void CompileJumpTableThunk(Address thunk, Address jump_target) { … }

class JumpTableRunner : public v8::base::Thread { … };

class JumpTablePatcher : public v8::base::Thread { … };

}  // namespace

// This test is intended to stress concurrent patching of jump-table slots. It
// uses the following setup:
//   1) Picks a particular slot of the jump-table. Slots are iterated over to
//      ensure multiple entries (at different offset alignments) are tested.
//   2) Starts multiple runners that spin through the above slot. The runners
//      use thunk code that will jump to the same jump-table slot repeatedly
//      until the {global_stop_bit} indicates a test-end condition.
//   3) Start a patcher that repeatedly patches the jump-table slot back and
//      forth between two thunk. If there is a race then chances are high that
//      one of the runners is currently executing the jump-table slot.
TEST(JumpTablePatchingStress) { … }

#undef __
#undef TRACE

}  // namespace wasm
}  // namespace internal
}  // namespace v8
chromium/v8/test/cctest/wasm/test-jump-table-assembler.cc
