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// 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.
#ifndef V8_WASM_JUMP_TABLE_ASSEMBLER_H_
#define V8_WASM_JUMP_TABLE_ASSEMBLER_H_
#include "src/macro-assembler.h"
#include "src/wasm/wasm-code-manager.h"
namespace v8 {
namespace internal {
namespace wasm {
class JumpTableAssembler : public TurboAssembler {
public:
// Instantiate a {JumpTableAssembler} for patching.
explicit JumpTableAssembler(Address slot_addr, int size = 256)
: TurboAssembler(nullptr, JumpTableAssemblerOptions(),
reinterpret_cast<void*>(slot_addr), size,
CodeObjectRequired::kNo) {}
#if V8_TARGET_ARCH_X64
static constexpr int kJumpTableSlotSize = 18;
#elif V8_TARGET_ARCH_IA32
static constexpr int kJumpTableSlotSize = 10;
#elif V8_TARGET_ARCH_ARM
static constexpr int kJumpTableSlotSize = 5 * kInstrSize;
#elif V8_TARGET_ARCH_ARM64
static constexpr int kJumpTableSlotSize = 3 * kInstructionSize;
#elif V8_TARGET_ARCH_S390X
static constexpr int kJumpTableSlotSize = 20;
#elif V8_TARGET_ARCH_S390
static constexpr int kJumpTableSlotSize = 14;
#elif V8_TARGET_ARCH_PPC64
static constexpr int kJumpTableSlotSize = 48;
#elif V8_TARGET_ARCH_PPC
static constexpr int kJumpTableSlotSize = 24;
#elif V8_TARGET_ARCH_MIPS
static constexpr int kJumpTableSlotSize = 6 * kInstrSize;
#elif V8_TARGET_ARCH_MIPS64
static constexpr int kJumpTableSlotSize = 8 * kInstrSize;
#else
static constexpr int kJumpTableSlotSize = 1;
#endif
// {JumpTableAssembler} is never used during snapshot generation, and its code
// must be independent of the code range of any isolate anyway. Just ensure
// that no relocation information is recorded, there is no buffer to store it
// since it is instantiated in patching mode in existing code directly.
static AssemblerOptions JumpTableAssemblerOptions() {
AssemblerOptions options;
options.disable_reloc_info_for_patching = true;
return options;
}
void EmitLazyCompileJumpSlot(uint32_t func_index,
Address lazy_compile_target);
void EmitJumpSlot(Address target);
void NopBytes(int bytes);
static void PatchJumpTableSlot(Address slot, Address new_target,
WasmCode::FlushICache flush_i_cache) {
JumpTableAssembler jsasm(slot);
jsasm.EmitJumpSlot(new_target);
jsasm.NopBytes(kJumpTableSlotSize - jsasm.pc_offset());
if (flush_i_cache) {
Assembler::FlushICache(slot, kJumpTableSlotSize);
}
}
};
} // namespace wasm
} // namespace internal
} // namespace v8
#endif // V8_WASM_JUMP_TABLE_ASSEMBLER_H_
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