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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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