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_X87 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_X87 186