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 #include "src/v8.h"
6 
7 #if V8_TARGET_ARCH_MIPS
8 
9 #include "src/codegen.h"
10 #include "src/ic/stub-cache.h"
11 
12 namespace v8 {
13 namespace internal {
14 
15 #define __ ACCESS_MASM(masm)
16 
17 
ProbeTable(Isolate * isolate,MacroAssembler * masm,Code::Flags flags,bool leave_frame,StubCache::Table table,Register receiver,Register name,Register offset,Register scratch,Register scratch2,Register offset_scratch)18 static void ProbeTable(Isolate* isolate, MacroAssembler* masm,
19                        Code::Flags flags, bool leave_frame,
20                        StubCache::Table table, Register receiver, Register name,
21                        // Number of the cache entry, not scaled.
22                        Register offset, Register scratch, Register scratch2,
23                        Register offset_scratch) {
24   ExternalReference key_offset(isolate->stub_cache()->key_reference(table));
25   ExternalReference value_offset(isolate->stub_cache()->value_reference(table));
26   ExternalReference map_offset(isolate->stub_cache()->map_reference(table));
27 
28   uint32_t key_off_addr = reinterpret_cast<uint32_t>(key_offset.address());
29   uint32_t value_off_addr = reinterpret_cast<uint32_t>(value_offset.address());
30   uint32_t map_off_addr = reinterpret_cast<uint32_t>(map_offset.address());
31 
32   // Check the relative positions of the address fields.
33   DCHECK(value_off_addr > key_off_addr);
34   DCHECK((value_off_addr - key_off_addr) % 4 == 0);
35   DCHECK((value_off_addr - key_off_addr) < (256 * 4));
36   DCHECK(map_off_addr > key_off_addr);
37   DCHECK((map_off_addr - key_off_addr) % 4 == 0);
38   DCHECK((map_off_addr - key_off_addr) < (256 * 4));
39 
40   Label miss;
41   Register base_addr = scratch;
42   scratch = no_reg;
43 
44   // Multiply by 3 because there are 3 fields per entry (name, code, map).
45   __ sll(offset_scratch, offset, 1);
46   __ Addu(offset_scratch, offset_scratch, offset);
47 
48   // Calculate the base address of the entry.
49   __ li(base_addr, Operand(key_offset));
50   __ sll(at, offset_scratch, kPointerSizeLog2);
51   __ Addu(base_addr, base_addr, at);
52 
53   // Check that the key in the entry matches the name.
54   __ lw(at, MemOperand(base_addr, 0));
55   __ Branch(&miss, ne, name, Operand(at));
56 
57   // Check the map matches.
58   __ lw(at, MemOperand(base_addr, map_off_addr - key_off_addr));
59   __ lw(scratch2, FieldMemOperand(receiver, HeapObject::kMapOffset));
60   __ Branch(&miss, ne, at, Operand(scratch2));
61 
62   // Get the code entry from the cache.
63   Register code = scratch2;
64   scratch2 = no_reg;
65   __ lw(code, MemOperand(base_addr, value_off_addr - key_off_addr));
66 
67   // Check that the flags match what we're looking for.
68   Register flags_reg = base_addr;
69   base_addr = no_reg;
70   __ lw(flags_reg, FieldMemOperand(code, Code::kFlagsOffset));
71   __ And(flags_reg, flags_reg, Operand(~Code::kFlagsNotUsedInLookup));
72   __ Branch(&miss, ne, flags_reg, Operand(flags));
73 
74 #ifdef DEBUG
75   if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {
76     __ jmp(&miss);
77   } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {
78     __ jmp(&miss);
79   }
80 #endif
81 
82   if (leave_frame) __ LeaveFrame(StackFrame::INTERNAL);
83 
84   // Jump to the first instruction in the code stub.
85   __ Addu(at, code, Operand(Code::kHeaderSize - kHeapObjectTag));
86   __ Jump(at);
87 
88   // Miss: fall through.
89   __ bind(&miss);
90 }
91 
92 
GenerateProbe(MacroAssembler * masm,Code::Flags flags,bool leave_frame,Register receiver,Register name,Register scratch,Register extra,Register extra2,Register extra3)93 void StubCache::GenerateProbe(MacroAssembler* masm, Code::Flags flags,
94                               bool leave_frame, Register receiver,
95                               Register name, Register scratch, Register extra,
96                               Register extra2, Register extra3) {
97   Isolate* isolate = masm->isolate();
98   Label miss;
99 
100   // Make sure that code is valid. The multiplying code relies on the
101   // entry size being 12.
102   DCHECK(sizeof(Entry) == 12);
103 
104   // Make sure the flags does not name a specific type.
105   DCHECK(Code::ExtractTypeFromFlags(flags) == 0);
106 
107   // Make sure that there are no register conflicts.
108   DCHECK(!scratch.is(receiver));
109   DCHECK(!scratch.is(name));
110   DCHECK(!extra.is(receiver));
111   DCHECK(!extra.is(name));
112   DCHECK(!extra.is(scratch));
113   DCHECK(!extra2.is(receiver));
114   DCHECK(!extra2.is(name));
115   DCHECK(!extra2.is(scratch));
116   DCHECK(!extra2.is(extra));
117 
118   // Check register validity.
119   DCHECK(!scratch.is(no_reg));
120   DCHECK(!extra.is(no_reg));
121   DCHECK(!extra2.is(no_reg));
122   DCHECK(!extra3.is(no_reg));
123 
124   Counters* counters = masm->isolate()->counters();
125   __ IncrementCounter(counters->megamorphic_stub_cache_probes(), 1, extra2,
126                       extra3);
127 
128   // Check that the receiver isn't a smi.
129   __ JumpIfSmi(receiver, &miss);
130 
131   // Get the map of the receiver and compute the hash.
132   __ lw(scratch, FieldMemOperand(name, Name::kHashFieldOffset));
133   __ lw(at, FieldMemOperand(receiver, HeapObject::kMapOffset));
134   __ Addu(scratch, scratch, at);
135   uint32_t mask = kPrimaryTableSize - 1;
136   // We shift out the last two bits because they are not part of the hash and
137   // they are always 01 for maps.
138   __ srl(scratch, scratch, kCacheIndexShift);
139   __ Xor(scratch, scratch, Operand((flags >> kCacheIndexShift) & mask));
140   __ And(scratch, scratch, Operand(mask));
141 
142   // Probe the primary table.
143   ProbeTable(isolate, masm, flags, leave_frame, kPrimary, receiver, name,
144              scratch, extra, extra2, extra3);
145 
146   // Primary miss: Compute hash for secondary probe.
147   __ srl(at, name, kCacheIndexShift);
148   __ Subu(scratch, scratch, at);
149   uint32_t mask2 = kSecondaryTableSize - 1;
150   __ Addu(scratch, scratch, Operand((flags >> kCacheIndexShift) & mask2));
151   __ And(scratch, scratch, Operand(mask2));
152 
153   // Probe the secondary table.
154   ProbeTable(isolate, masm, flags, leave_frame, kSecondary, receiver, name,
155              scratch, extra, extra2, extra3);
156 
157   // Cache miss: Fall-through and let caller handle the miss by
158   // entering the runtime system.
159   __ bind(&miss);
160   __ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1, extra2,
161                       extra3);
162 }
163 
164 
165 #undef __
166 }
167 }  // namespace v8::internal
168 
169 #endif  // V8_TARGET_ARCH_MIPS
170