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| 1 // Copyright 2012 the V8 project authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #if V8_TARGET_ARCH_X64 | |
| 6 | |
| 7 #include "src/codegen.h" | |
| 8 #include "src/ic/ic.h" | |
| 9 #include "src/ic/stub-cache.h" | |
| 10 #include "src/interface-descriptors.h" | |
| 11 | |
| 12 namespace v8 { | |
| 13 namespace internal { | |
| 14 | |
| 15 #define __ ACCESS_MASM(masm) | |
| 16 | |
| 17 static void ProbeTable(StubCache* stub_cache, MacroAssembler* masm, | |
| 18 StubCache::Table table, Register receiver, Register name, | |
| 19 // The offset is scaled by 4, based on | |
| 20 // kCacheIndexShift, which is two bits | |
| 21 Register offset) { | |
| 22 // We need to scale up the pointer by 2 when the offset is scaled by less | |
| 23 // than the pointer size. | |
| 24 DCHECK(kPointerSize == kInt64Size | |
| 25 ? kPointerSizeLog2 == StubCache::kCacheIndexShift + 1 | |
| 26 : kPointerSizeLog2 == StubCache::kCacheIndexShift); | |
| 27 ScaleFactor scale_factor = kPointerSize == kInt64Size ? times_2 : times_1; | |
| 28 | |
| 29 DCHECK_EQ(3u * kPointerSize, sizeof(StubCache::Entry)); | |
| 30 // The offset register holds the entry offset times four (due to masking | |
| 31 // and shifting optimizations). | |
| 32 ExternalReference key_offset(stub_cache->key_reference(table)); | |
| 33 ExternalReference value_offset(stub_cache->value_reference(table)); | |
| 34 Label miss; | |
| 35 | |
| 36 // Multiply by 3 because there are 3 fields per entry (name, code, map). | |
| 37 __ leap(offset, Operand(offset, offset, times_2, 0)); | |
| 38 | |
| 39 __ LoadAddress(kScratchRegister, key_offset); | |
| 40 | |
| 41 // Check that the key in the entry matches the name. | |
| 42 __ cmpp(name, Operand(kScratchRegister, offset, scale_factor, 0)); | |
| 43 __ j(not_equal, &miss); | |
| 44 | |
| 45 // Get the map entry from the cache. | |
| 46 // Use key_offset + kPointerSize * 2, rather than loading map_offset. | |
| 47 DCHECK(stub_cache->map_reference(table).address() - | |
| 48 stub_cache->key_reference(table).address() == | |
| 49 kPointerSize * 2); | |
| 50 __ movp(kScratchRegister, | |
| 51 Operand(kScratchRegister, offset, scale_factor, kPointerSize * 2)); | |
| 52 __ cmpp(kScratchRegister, FieldOperand(receiver, HeapObject::kMapOffset)); | |
| 53 __ j(not_equal, &miss); | |
| 54 | |
| 55 // Get the code entry from the cache. | |
| 56 __ LoadAddress(kScratchRegister, value_offset); | |
| 57 __ movp(kScratchRegister, Operand(kScratchRegister, offset, scale_factor, 0)); | |
| 58 | |
| 59 #ifdef DEBUG | |
| 60 if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) { | |
| 61 __ jmp(&miss); | |
| 62 } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) { | |
| 63 __ jmp(&miss); | |
| 64 } | |
| 65 #endif | |
| 66 | |
| 67 // Jump to the first instruction in the code stub. | |
| 68 __ addp(kScratchRegister, Immediate(Code::kHeaderSize - kHeapObjectTag)); | |
| 69 __ jmp(kScratchRegister); | |
| 70 | |
| 71 __ bind(&miss); | |
| 72 } | |
| 73 | |
| 74 void StubCache::GenerateProbe(MacroAssembler* masm, Register receiver, | |
| 75 Register name, Register scratch, Register extra, | |
| 76 Register extra2, Register extra3) { | |
| 77 Label miss; | |
| 78 USE(extra); // The register extra is not used on the X64 platform. | |
| 79 USE(extra2); // The register extra2 is not used on the X64 platform. | |
| 80 USE(extra3); // The register extra2 is not used on the X64 platform. | |
| 81 // Make sure that code is valid. The multiplying code relies on the | |
| 82 // entry size being 3 * kPointerSize. | |
| 83 DCHECK(sizeof(Entry) == 3 * kPointerSize); | |
| 84 | |
| 85 // Make sure that there are no register conflicts. | |
| 86 DCHECK(!scratch.is(receiver)); | |
| 87 DCHECK(!scratch.is(name)); | |
| 88 | |
| 89 // Check scratch register is valid, extra and extra2 are unused. | |
| 90 DCHECK(!scratch.is(no_reg)); | |
| 91 DCHECK(extra2.is(no_reg)); | |
| 92 DCHECK(extra3.is(no_reg)); | |
| 93 | |
| 94 #ifdef DEBUG | |
| 95 // If vector-based ics are in use, ensure that scratch doesn't conflict with | |
| 96 // the vector and slot registers, which need to be preserved for a handler | |
| 97 // call or miss. | |
| 98 if (IC::ICUseVector(ic_kind_)) { | |
| 99 if (ic_kind_ == Code::LOAD_IC || ic_kind_ == Code::KEYED_LOAD_IC) { | |
| 100 Register vector = LoadWithVectorDescriptor::VectorRegister(); | |
| 101 Register slot = LoadDescriptor::SlotRegister(); | |
| 102 DCHECK(!AreAliased(vector, slot, scratch)); | |
| 103 } else { | |
| 104 DCHECK(ic_kind_ == Code::STORE_IC || ic_kind_ == Code::KEYED_STORE_IC); | |
| 105 Register vector = StoreWithVectorDescriptor::VectorRegister(); | |
| 106 Register slot = StoreWithVectorDescriptor::SlotRegister(); | |
| 107 DCHECK(!AreAliased(vector, slot, scratch)); | |
| 108 } | |
| 109 } | |
| 110 #endif | |
| 111 | |
| 112 Counters* counters = masm->isolate()->counters(); | |
| 113 __ IncrementCounter(counters->megamorphic_stub_cache_probes(), 1); | |
| 114 | |
| 115 // Check that the receiver isn't a smi. | |
| 116 __ JumpIfSmi(receiver, &miss); | |
| 117 | |
| 118 // Get the map of the receiver and compute the hash. | |
| 119 __ movl(scratch, FieldOperand(name, Name::kHashFieldOffset)); | |
| 120 // Use only the low 32 bits of the map pointer. | |
| 121 __ addl(scratch, FieldOperand(receiver, HeapObject::kMapOffset)); | |
| 122 __ xorp(scratch, Immediate(kPrimaryMagic)); | |
| 123 // We mask out the last two bits because they are not part of the hash and | |
| 124 // they are always 01 for maps. Also in the two 'and' instructions below. | |
| 125 __ andp(scratch, Immediate((kPrimaryTableSize - 1) << kCacheIndexShift)); | |
| 126 | |
| 127 // Probe the primary table. | |
| 128 ProbeTable(this, masm, kPrimary, receiver, name, scratch); | |
| 129 | |
| 130 // Primary miss: Compute hash for secondary probe. | |
| 131 __ movl(scratch, FieldOperand(name, Name::kHashFieldOffset)); | |
| 132 __ addl(scratch, FieldOperand(receiver, HeapObject::kMapOffset)); | |
| 133 __ xorp(scratch, Immediate(kPrimaryMagic)); | |
| 134 __ andp(scratch, Immediate((kPrimaryTableSize - 1) << kCacheIndexShift)); | |
| 135 __ subl(scratch, name); | |
| 136 __ addl(scratch, Immediate(kSecondaryMagic)); | |
| 137 __ andp(scratch, Immediate((kSecondaryTableSize - 1) << kCacheIndexShift)); | |
| 138 | |
| 139 // Probe the secondary table. | |
| 140 ProbeTable(this, masm, kSecondary, receiver, name, scratch); | |
| 141 | |
| 142 // Cache miss: Fall-through and let caller handle the miss by | |
| 143 // entering the runtime system. | |
| 144 __ bind(&miss); | |
| 145 __ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1); | |
| 146 } | |
| 147 | |
| 148 | |
| 149 #undef __ | |
| 150 } // namespace internal | |
| 151 } // namespace v8 | |
| 152 | |
| 153 #endif // V8_TARGET_ARCH_X64 | |
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