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// Copyright 2013 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.
#if V8_TARGET_ARCH_ARM64
#include "src/codegen.h"
#include "src/ic/ic.h"
#include "src/ic/stub-cache.h"
#include "src/interface-descriptors.h"
namespace v8 {
namespace internal {
#define __ ACCESS_MASM(masm)
// Probe primary or secondary table.
// If the entry is found in the cache, the generated code jump to the first
// instruction of the stub in the cache.
// If there is a miss the code fall trough.
//
// 'receiver', 'name' and 'offset' registers are preserved on miss.
static void ProbeTable(StubCache* stub_cache, MacroAssembler* masm,
StubCache::Table table, Register receiver, Register name,
// The offset is scaled by 4, based on
// kCacheIndexShift, which is two bits
Register offset, Register scratch, Register scratch2,
Register scratch3) {
// Some code below relies on the fact that the Entry struct contains
// 3 pointers (name, code, map).
STATIC_ASSERT(sizeof(StubCache::Entry) == (3 * kPointerSize));
ExternalReference key_offset(stub_cache->key_reference(table));
ExternalReference value_offset(stub_cache->value_reference(table));
ExternalReference map_offset(stub_cache->map_reference(table));
uintptr_t key_off_addr = reinterpret_cast<uintptr_t>(key_offset.address());
uintptr_t value_off_addr =
reinterpret_cast<uintptr_t>(value_offset.address());
uintptr_t map_off_addr = reinterpret_cast<uintptr_t>(map_offset.address());
Label miss;
DCHECK(!AreAliased(name, offset, scratch, scratch2, scratch3));
// Multiply by 3 because there are 3 fields per entry.
__ Add(scratch3, offset, Operand(offset, LSL, 1));
// Calculate the base address of the entry.
__ Mov(scratch, key_offset);
__ Add(
scratch, scratch,
Operand(scratch3, LSL, kPointerSizeLog2 - StubCache::kCacheIndexShift));
// Check that the key in the entry matches the name.
__ Ldr(scratch2, MemOperand(scratch));
__ Cmp(name, scratch2);
__ B(ne, &miss);
// Check the map matches.
__ Ldr(scratch2, MemOperand(scratch, map_off_addr - key_off_addr));
__ Ldr(scratch3, FieldMemOperand(receiver, HeapObject::kMapOffset));
__ Cmp(scratch2, scratch3);
__ B(ne, &miss);
// Get the code entry from the cache.
__ Ldr(scratch, MemOperand(scratch, value_off_addr - key_off_addr));
#ifdef DEBUG
if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {
__ B(&miss);
} else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {
__ B(&miss);
}
#endif
// Jump to the first instruction in the code stub.
__ Add(scratch, scratch, Code::kHeaderSize - kHeapObjectTag);
__ Br(scratch);
// Miss: fall through.
__ Bind(&miss);
}
void StubCache::GenerateProbe(MacroAssembler* masm, Register receiver,
Register name, Register scratch, Register extra,
Register extra2, Register extra3) {
Label miss;
// Make sure that there are no register conflicts.
DCHECK(!AreAliased(receiver, name, scratch, extra, extra2, extra3));
// Make sure extra and extra2 registers are valid.
DCHECK(!extra.is(no_reg));
DCHECK(!extra2.is(no_reg));
DCHECK(!extra3.is(no_reg));
#ifdef DEBUG
// If vector-based ics are in use, ensure that scratch, extra, extra2 and
// extra3 don't conflict with the vector and slot registers, which need
// to be preserved for a handler call or miss.
if (IC::ICUseVector(ic_kind_)) {
Register vector, slot;
if (ic_kind_ == Code::STORE_IC || ic_kind_ == Code::KEYED_STORE_IC) {
vector = StoreWithVectorDescriptor::VectorRegister();
slot = StoreWithVectorDescriptor::SlotRegister();
} else {
DCHECK(ic_kind_ == Code::LOAD_IC || ic_kind_ == Code::KEYED_LOAD_IC);
vector = LoadWithVectorDescriptor::VectorRegister();
slot = LoadWithVectorDescriptor::SlotRegister();
}
DCHECK(!AreAliased(vector, slot, scratch, extra, extra2, extra3));
}
#endif
Counters* counters = masm->isolate()->counters();
__ IncrementCounter(counters->megamorphic_stub_cache_probes(), 1, extra2,
extra3);
// Check that the receiver isn't a smi.
__ JumpIfSmi(receiver, &miss);
// Compute the hash for primary table.
__ Ldr(scratch.W(), FieldMemOperand(name, Name::kHashFieldOffset));
__ Ldr(extra, FieldMemOperand(receiver, HeapObject::kMapOffset));
__ Add(scratch, scratch, extra);
__ Eor(scratch, scratch, kPrimaryMagic);
__ And(scratch, scratch,
Operand((kPrimaryTableSize - 1) << kCacheIndexShift));
// Probe the primary table.
ProbeTable(this, masm, kPrimary, receiver, name, scratch, extra, extra2,
extra3);
// Primary miss: Compute hash for secondary table.
__ Sub(scratch, scratch, Operand(name));
__ Add(scratch, scratch, Operand(kSecondaryMagic));
__ And(scratch, scratch,
Operand((kSecondaryTableSize - 1) << kCacheIndexShift));
// Probe the secondary table.
ProbeTable(this, masm, kSecondary, receiver, name, scratch, extra, extra2,
extra3);
// Cache miss: Fall-through and let caller handle the miss by
// entering the runtime system.
__ Bind(&miss);
__ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1, extra2,
extra3);
}
} // namespace internal
} // namespace v8
#endif // V8_TARGET_ARCH_ARM64
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