1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
// Copyright 2012 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_ARM
#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)
static void ProbeTable(Isolate* isolate, MacroAssembler* masm,
Code::Kind ic_kind, Code::Flags flags,
StubCache::Table table, Register receiver, Register name,
// Number of the cache entry, not scaled.
Register offset, Register scratch, Register scratch2,
Register offset_scratch) {
ExternalReference key_offset(isolate->stub_cache()->key_reference(table));
ExternalReference value_offset(isolate->stub_cache()->value_reference(table));
ExternalReference map_offset(isolate->stub_cache()->map_reference(table));
uint32_t key_off_addr = reinterpret_cast<uint32_t>(key_offset.address());
uint32_t value_off_addr = reinterpret_cast<uint32_t>(value_offset.address());
uint32_t map_off_addr = reinterpret_cast<uint32_t>(map_offset.address());
// Check the relative positions of the address fields.
DCHECK(value_off_addr > key_off_addr);
DCHECK((value_off_addr - key_off_addr) % 4 == 0);
DCHECK((value_off_addr - key_off_addr) < (256 * 4));
DCHECK(map_off_addr > key_off_addr);
DCHECK((map_off_addr - key_off_addr) % 4 == 0);
DCHECK((map_off_addr - key_off_addr) < (256 * 4));
Label miss;
Register base_addr = scratch;
scratch = no_reg;
// Multiply by 3 because there are 3 fields per entry (name, code, map).
__ add(offset_scratch, offset, Operand(offset, LSL, 1));
// Calculate the base address of the entry.
__ mov(base_addr, Operand(key_offset));
__ add(base_addr, base_addr, Operand(offset_scratch, LSL, kPointerSizeLog2));
// Check that the key in the entry matches the name.
__ ldr(ip, MemOperand(base_addr, 0));
__ cmp(name, ip);
__ b(ne, &miss);
// Check the map matches.
__ ldr(ip, MemOperand(base_addr, map_off_addr - key_off_addr));
__ ldr(scratch2, FieldMemOperand(receiver, HeapObject::kMapOffset));
__ cmp(ip, scratch2);
__ b(ne, &miss);
// Get the code entry from the cache.
Register code = scratch2;
scratch2 = no_reg;
__ ldr(code, MemOperand(base_addr, value_off_addr - key_off_addr));
// Check that the flags match what we're looking for.
Register flags_reg = base_addr;
base_addr = no_reg;
__ ldr(flags_reg, FieldMemOperand(code, Code::kFlagsOffset));
// It's a nice optimization if this constant is encodable in the bic insn.
uint32_t mask = Code::kFlagsNotUsedInLookup;
DCHECK(__ ImmediateFitsAddrMode1Instruction(mask));
__ bic(flags_reg, flags_reg, Operand(mask));
__ cmp(flags_reg, Operand(flags));
__ b(ne, &miss);
#ifdef DEBUG
if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {
__ jmp(&miss);
} else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {
__ jmp(&miss);
}
#endif
// Jump to the first instruction in the code stub.
__ add(pc, code, Operand(Code::kHeaderSize - kHeapObjectTag));
// Miss: fall through.
__ bind(&miss);
}
void StubCache::GenerateProbe(MacroAssembler* masm, Code::Kind ic_kind,
Code::Flags flags, Register receiver,
Register name, Register scratch, Register extra,
Register extra2, Register extra3) {
Isolate* isolate = masm->isolate();
Label miss;
// Make sure that code is valid. The multiplying code relies on the
// entry size being 12.
DCHECK(sizeof(Entry) == 12);
// Make sure the flags does not name a specific type.
DCHECK(Code::ExtractTypeFromFlags(flags) == 0);
// Make sure that there are no register conflicts.
DCHECK(!AreAliased(receiver, name, scratch, extra, extra2, extra3));
// Check scratch, extra and extra2 registers are valid.
DCHECK(!scratch.is(no_reg));
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 = LoadWithVectorDescriptor::VectorRegister();
Register 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);
// Get the map of the receiver and compute the hash.
__ ldr(scratch, FieldMemOperand(name, Name::kHashFieldOffset));
__ ldr(ip, FieldMemOperand(receiver, HeapObject::kMapOffset));
__ add(scratch, scratch, Operand(ip));
uint32_t mask = kPrimaryTableSize - 1;
// We shift out the last two bits because they are not part of the hash and
// they are always 01 for maps.
__ mov(scratch, Operand(scratch, LSR, kCacheIndexShift));
// Mask down the eor argument to the minimum to keep the immediate
// ARM-encodable.
__ eor(scratch, scratch, Operand((flags >> kCacheIndexShift) & mask));
// Prefer and_ to ubfx here because ubfx takes 2 cycles.
__ and_(scratch, scratch, Operand(mask));
// Probe the primary table.
ProbeTable(isolate, masm, ic_kind, flags, kPrimary, receiver, name, scratch,
extra, extra2, extra3);
// Primary miss: Compute hash for secondary probe.
__ sub(scratch, scratch, Operand(name, LSR, kCacheIndexShift));
uint32_t mask2 = kSecondaryTableSize - 1;
__ add(scratch, scratch, Operand((flags >> kCacheIndexShift) & mask2));
__ and_(scratch, scratch, Operand(mask2));
// Probe the secondary table.
ProbeTable(isolate, masm, ic_kind, flags, 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);
}
#undef __
} // namespace internal
} // namespace v8
#endif // V8_TARGET_ARCH_ARM
|
