1 // Copyright 2013 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_ARM64 8 9 #include "src/codegen.h" 10 #include "src/ic/stub-cache.h" 11 12 namespace v8 { 13 namespace internal { 14 15 16 #define __ ACCESS_MASM(masm) 17 18 19 // Probe primary or secondary table. 20 // If the entry is found in the cache, the generated code jump to the first 21 // instruction of the stub in the cache. 22 // If there is a miss the code fall trough. 23 // 24 // 'receiver', 'name' and 'offset' registers are preserved on miss. 25 static void ProbeTable(Isolate* isolate, MacroAssembler* masm, 26 Code::Flags flags, bool leave_frame, 27 StubCache::Table table, Register receiver, Register name, 28 Register offset, Register scratch, Register scratch2, 29 Register scratch3) { 30 // Some code below relies on the fact that the Entry struct contains 31 // 3 pointers (name, code, map). 32 STATIC_ASSERT(sizeof(StubCache::Entry) == (3 * kPointerSize)); 33 34 ExternalReference key_offset(isolate->stub_cache()->key_reference(table)); 35 ExternalReference value_offset(isolate->stub_cache()->value_reference(table)); 36 ExternalReference map_offset(isolate->stub_cache()->map_reference(table)); 37 38 uintptr_t key_off_addr = reinterpret_cast<uintptr_t>(key_offset.address()); 39 uintptr_t value_off_addr = 40 reinterpret_cast<uintptr_t>(value_offset.address()); 41 uintptr_t map_off_addr = reinterpret_cast<uintptr_t>(map_offset.address()); 42 43 Label miss; 44 45 DCHECK(!AreAliased(name, offset, scratch, scratch2, scratch3)); 46 47 // Multiply by 3 because there are 3 fields per entry. 48 __ Add(scratch3, offset, Operand(offset, LSL, 1)); 49 50 // Calculate the base address of the entry. 51 __ Mov(scratch, key_offset); 52 __ Add(scratch, scratch, Operand(scratch3, LSL, kPointerSizeLog2)); 53 54 // Check that the key in the entry matches the name. 55 __ Ldr(scratch2, MemOperand(scratch)); 56 __ Cmp(name, scratch2); 57 __ B(ne, &miss); 58 59 // Check the map matches. 60 __ Ldr(scratch2, MemOperand(scratch, map_off_addr - key_off_addr)); 61 __ Ldr(scratch3, FieldMemOperand(receiver, HeapObject::kMapOffset)); 62 __ Cmp(scratch2, scratch3); 63 __ B(ne, &miss); 64 65 // Get the code entry from the cache. 66 __ Ldr(scratch, MemOperand(scratch, value_off_addr - key_off_addr)); 67 68 // Check that the flags match what we're looking for. 69 __ Ldr(scratch2.W(), FieldMemOperand(scratch, Code::kFlagsOffset)); 70 __ Bic(scratch2.W(), scratch2.W(), Code::kFlagsNotUsedInLookup); 71 __ Cmp(scratch2.W(), flags); 72 __ B(ne, &miss); 73 74 #ifdef DEBUG 75 if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) { 76 __ B(&miss); 77 } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) { 78 __ B(&miss); 79 } 80 #endif 81 82 if (leave_frame) __ LeaveFrame(StackFrame::INTERNAL); 83 84 // Jump to the first instruction in the code stub. 85 __ Add(scratch, scratch, Code::kHeaderSize - kHeapObjectTag); 86 __ Br(scratch); 87 88 // Miss: fall through. 89 __ Bind(&miss); 90 } 91 92 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 the flags does not name a specific type. 101 DCHECK(Code::ExtractTypeFromFlags(flags) == 0); 102 103 // Make sure that there are no register conflicts. 104 DCHECK(!AreAliased(receiver, name, scratch, extra, extra2, extra3)); 105 106 // Make sure extra and extra2 registers are valid. 107 DCHECK(!extra.is(no_reg)); 108 DCHECK(!extra2.is(no_reg)); 109 DCHECK(!extra3.is(no_reg)); 110 111 Counters* counters = masm->isolate()->counters(); 112 __ IncrementCounter(counters->megamorphic_stub_cache_probes(), 1, extra2, 113 extra3); 114 115 // Check that the receiver isn't a smi. 116 __ JumpIfSmi(receiver, &miss); 117 118 // Compute the hash for primary table. 119 __ Ldr(scratch, FieldMemOperand(name, Name::kHashFieldOffset)); 120 __ Ldr(extra, FieldMemOperand(receiver, HeapObject::kMapOffset)); 121 __ Add(scratch, scratch, extra); 122 __ Eor(scratch, scratch, flags); 123 // We shift out the last two bits because they are not part of the hash. 124 __ Ubfx(scratch, scratch, kCacheIndexShift, 125 CountTrailingZeros(kPrimaryTableSize, 64)); 126 127 // Probe the primary table. 128 ProbeTable(isolate, masm, flags, leave_frame, kPrimary, receiver, name, 129 scratch, extra, extra2, extra3); 130 131 // Primary miss: Compute hash for secondary table. 132 __ Sub(scratch, scratch, Operand(name, LSR, kCacheIndexShift)); 133 __ Add(scratch, scratch, flags >> kCacheIndexShift); 134 __ And(scratch, scratch, kSecondaryTableSize - 1); 135 136 // Probe the secondary table. 137 ProbeTable(isolate, masm, flags, leave_frame, kSecondary, receiver, name, 138 scratch, extra, extra2, extra3); 139 140 // Cache miss: Fall-through and let caller handle the miss by 141 // entering the runtime system. 142 __ Bind(&miss); 143 __ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1, extra2, 144 extra3); 145 } 146 } 147 } // namespace v8::internal 148 149 #endif // V8_TARGET_ARCH_ARM64 150
