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_IA32
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
ProbeTable(StubCache * stub_cache,MacroAssembler * masm,StubCache::Table table,Register name,Register receiver,Register offset,Register extra)17 static void ProbeTable(StubCache* stub_cache, MacroAssembler* masm,
18 StubCache::Table table, Register name, Register receiver,
19 // The offset is scaled by 4, based on
20 // kCacheIndexShift, which is two bits
21 Register offset, Register extra) {
22 ExternalReference key_offset(stub_cache->key_reference(table));
23 ExternalReference value_offset(stub_cache->value_reference(table));
24 ExternalReference map_offset(stub_cache->map_reference(table));
25
26 Label miss;
27 Code::Kind ic_kind = stub_cache->ic_kind();
28 bool is_vector_store =
29 IC::ICUseVector(ic_kind) &&
30 (ic_kind == Code::STORE_IC || ic_kind == Code::KEYED_STORE_IC);
31
32 // Multiply by 3 because there are 3 fields per entry (name, code, map).
33 __ lea(offset, Operand(offset, offset, times_2, 0));
34
35 if (extra.is_valid()) {
36 // Get the code entry from the cache.
37 __ mov(extra, Operand::StaticArray(offset, times_1, value_offset));
38
39 // Check that the key in the entry matches the name.
40 __ cmp(name, Operand::StaticArray(offset, times_1, key_offset));
41 __ j(not_equal, &miss);
42
43 // Check the map matches.
44 __ mov(offset, Operand::StaticArray(offset, times_1, map_offset));
45 __ cmp(offset, FieldOperand(receiver, HeapObject::kMapOffset));
46 __ j(not_equal, &miss);
47
48 #ifdef DEBUG
49 if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {
50 __ jmp(&miss);
51 } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {
52 __ jmp(&miss);
53 }
54 #endif
55
56 if (is_vector_store) {
57 // The value, vector and slot were passed to the IC on the stack and
58 // they are still there. So we can just jump to the handler.
59 DCHECK(extra.is(StoreWithVectorDescriptor::SlotRegister()));
60 __ add(extra, Immediate(Code::kHeaderSize - kHeapObjectTag));
61 __ jmp(extra);
62 } else {
63 // The vector and slot were pushed onto the stack before starting the
64 // probe, and need to be dropped before calling the handler.
65 __ pop(LoadWithVectorDescriptor::VectorRegister());
66 __ pop(LoadDescriptor::SlotRegister());
67 __ add(extra, Immediate(Code::kHeaderSize - kHeapObjectTag));
68 __ jmp(extra);
69 }
70
71 __ bind(&miss);
72 } else {
73 DCHECK(ic_kind == Code::STORE_IC || ic_kind == Code::KEYED_STORE_IC);
74
75 // Save the offset on the stack.
76 __ push(offset);
77
78 // Check that the key in the entry matches the name.
79 __ cmp(name, Operand::StaticArray(offset, times_1, key_offset));
80 __ j(not_equal, &miss);
81
82 // Check the map matches.
83 __ mov(offset, Operand::StaticArray(offset, times_1, map_offset));
84 __ cmp(offset, FieldOperand(receiver, HeapObject::kMapOffset));
85 __ j(not_equal, &miss);
86
87 // Restore offset register.
88 __ mov(offset, Operand(esp, 0));
89
90 // Get the code entry from the cache.
91 __ mov(offset, Operand::StaticArray(offset, times_1, value_offset));
92
93 #ifdef DEBUG
94 if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {
95 __ jmp(&miss);
96 } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {
97 __ jmp(&miss);
98 }
99 #endif
100
101 // Restore offset and re-load code entry from cache.
102 __ pop(offset);
103 __ mov(offset, Operand::StaticArray(offset, times_1, value_offset));
104
105 // Jump to the first instruction in the code stub.
106 if (is_vector_store) {
107 DCHECK(offset.is(StoreWithVectorDescriptor::SlotRegister()));
108 }
109 __ add(offset, Immediate(Code::kHeaderSize - kHeapObjectTag));
110 __ jmp(offset);
111
112 // Pop at miss.
113 __ bind(&miss);
114 __ pop(offset);
115 }
116 }
117
GenerateProbe(MacroAssembler * masm,Register receiver,Register name,Register scratch,Register extra,Register extra2,Register extra3)118 void StubCache::GenerateProbe(MacroAssembler* masm, Register receiver,
119 Register name, Register scratch, Register extra,
120 Register extra2, Register extra3) {
121 Label miss;
122
123 // Assert that code is valid. The multiplying code relies on the entry size
124 // being 12.
125 DCHECK(sizeof(Entry) == 12);
126
127 // Assert that there are no register conflicts.
128 DCHECK(!scratch.is(receiver));
129 DCHECK(!scratch.is(name));
130 DCHECK(!extra.is(receiver));
131 DCHECK(!extra.is(name));
132 DCHECK(!extra.is(scratch));
133
134 // Assert scratch and extra registers are valid, and extra2/3 are unused.
135 DCHECK(!scratch.is(no_reg));
136 DCHECK(extra2.is(no_reg));
137 DCHECK(extra3.is(no_reg));
138
139 Register offset = scratch;
140 scratch = no_reg;
141
142 Counters* counters = masm->isolate()->counters();
143 __ IncrementCounter(counters->megamorphic_stub_cache_probes(), 1);
144
145 // Check that the receiver isn't a smi.
146 __ JumpIfSmi(receiver, &miss);
147
148 // Get the map of the receiver and compute the hash.
149 __ mov(offset, FieldOperand(name, Name::kHashFieldOffset));
150 __ add(offset, FieldOperand(receiver, HeapObject::kMapOffset));
151 __ xor_(offset, kPrimaryMagic);
152 // We mask out the last two bits because they are not part of the hash and
153 // they are always 01 for maps. Also in the two 'and' instructions below.
154 __ and_(offset, (kPrimaryTableSize - 1) << kCacheIndexShift);
155 // ProbeTable expects the offset to be pointer scaled, which it is, because
156 // the heap object tag size is 2 and the pointer size log 2 is also 2.
157 DCHECK(kCacheIndexShift == kPointerSizeLog2);
158
159 // Probe the primary table.
160 ProbeTable(this, masm, kPrimary, name, receiver, offset, extra);
161
162 // Primary miss: Compute hash for secondary probe.
163 __ mov(offset, FieldOperand(name, Name::kHashFieldOffset));
164 __ add(offset, FieldOperand(receiver, HeapObject::kMapOffset));
165 __ xor_(offset, kPrimaryMagic);
166 __ and_(offset, (kPrimaryTableSize - 1) << kCacheIndexShift);
167 __ sub(offset, name);
168 __ add(offset, Immediate(kSecondaryMagic));
169 __ and_(offset, (kSecondaryTableSize - 1) << kCacheIndexShift);
170
171 // Probe the secondary table.
172 ProbeTable(this, masm, kSecondary, name, receiver, offset, extra);
173
174 // Cache miss: Fall-through and let caller handle the miss by
175 // entering the runtime system.
176 __ bind(&miss);
177 __ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1);
178 }
179
180
181 #undef __
182 } // namespace internal
183 } // namespace v8
184
185 #endif // V8_TARGET_ARCH_IA32
186