Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 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 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 5 | #include "src/arm64/codegen-arm64.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 6 | |
| 7 | #if V8_TARGET_ARCH_ARM64 |
| 8 | |
| 9 | #include "src/arm64/simulator-arm64.h" |
| 10 | #include "src/codegen.h" |
| 11 | #include "src/macro-assembler.h" |
| 12 | |
| 13 | namespace v8 { |
| 14 | namespace internal { |
| 15 | |
| 16 | #define __ ACCESS_MASM(masm) |
| 17 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 18 | UnaryMathFunctionWithIsolate CreateSqrtFunction(Isolate* isolate) { |
| 19 | return nullptr; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 20 | } |
| 21 | |
| 22 | |
| 23 | // ------------------------------------------------------------------------- |
| 24 | // Platform-specific RuntimeCallHelper functions. |
| 25 | |
| 26 | void StubRuntimeCallHelper::BeforeCall(MacroAssembler* masm) const { |
| 27 | masm->EnterFrame(StackFrame::INTERNAL); |
| 28 | DCHECK(!masm->has_frame()); |
| 29 | masm->set_has_frame(true); |
| 30 | } |
| 31 | |
| 32 | |
| 33 | void StubRuntimeCallHelper::AfterCall(MacroAssembler* masm) const { |
| 34 | masm->LeaveFrame(StackFrame::INTERNAL); |
| 35 | DCHECK(masm->has_frame()); |
| 36 | masm->set_has_frame(false); |
| 37 | } |
| 38 | |
| 39 | |
| 40 | // ------------------------------------------------------------------------- |
| 41 | // Code generators |
| 42 | |
| 43 | void ElementsTransitionGenerator::GenerateMapChangeElementsTransition( |
| 44 | MacroAssembler* masm, |
| 45 | Register receiver, |
| 46 | Register key, |
| 47 | Register value, |
| 48 | Register target_map, |
| 49 | AllocationSiteMode mode, |
| 50 | Label* allocation_memento_found) { |
| 51 | ASM_LOCATION( |
| 52 | "ElementsTransitionGenerator::GenerateMapChangeElementsTransition"); |
| 53 | DCHECK(!AreAliased(receiver, key, value, target_map)); |
| 54 | |
| 55 | if (mode == TRACK_ALLOCATION_SITE) { |
| 56 | DCHECK(allocation_memento_found != NULL); |
| 57 | __ JumpIfJSArrayHasAllocationMemento(receiver, x10, x11, |
| 58 | allocation_memento_found); |
| 59 | } |
| 60 | |
| 61 | // Set transitioned map. |
| 62 | __ Str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset)); |
| 63 | __ RecordWriteField(receiver, |
| 64 | HeapObject::kMapOffset, |
| 65 | target_map, |
| 66 | x10, |
| 67 | kLRHasNotBeenSaved, |
| 68 | kDontSaveFPRegs, |
| 69 | EMIT_REMEMBERED_SET, |
| 70 | OMIT_SMI_CHECK); |
| 71 | } |
| 72 | |
| 73 | |
| 74 | void ElementsTransitionGenerator::GenerateSmiToDouble( |
| 75 | MacroAssembler* masm, |
| 76 | Register receiver, |
| 77 | Register key, |
| 78 | Register value, |
| 79 | Register target_map, |
| 80 | AllocationSiteMode mode, |
| 81 | Label* fail) { |
| 82 | ASM_LOCATION("ElementsTransitionGenerator::GenerateSmiToDouble"); |
| 83 | Label gc_required, only_change_map; |
| 84 | Register elements = x4; |
| 85 | Register length = x5; |
| 86 | Register array_size = x6; |
| 87 | Register array = x7; |
| 88 | |
| 89 | Register scratch = x6; |
| 90 | |
| 91 | // Verify input registers don't conflict with locals. |
| 92 | DCHECK(!AreAliased(receiver, key, value, target_map, |
| 93 | elements, length, array_size, array)); |
| 94 | |
| 95 | if (mode == TRACK_ALLOCATION_SITE) { |
| 96 | __ JumpIfJSArrayHasAllocationMemento(receiver, x10, x11, fail); |
| 97 | } |
| 98 | |
| 99 | // Check for empty arrays, which only require a map transition and no changes |
| 100 | // to the backing store. |
| 101 | __ Ldr(elements, FieldMemOperand(receiver, JSObject::kElementsOffset)); |
| 102 | __ JumpIfRoot(elements, Heap::kEmptyFixedArrayRootIndex, &only_change_map); |
| 103 | |
| 104 | __ Push(lr); |
| 105 | __ Ldrsw(length, UntagSmiFieldMemOperand(elements, |
| 106 | FixedArray::kLengthOffset)); |
| 107 | |
| 108 | // Allocate new FixedDoubleArray. |
| 109 | __ Lsl(array_size, length, kDoubleSizeLog2); |
| 110 | __ Add(array_size, array_size, FixedDoubleArray::kHeaderSize); |
| 111 | __ Allocate(array_size, array, x10, x11, &gc_required, DOUBLE_ALIGNMENT); |
| 112 | // Register array is non-tagged heap object. |
| 113 | |
| 114 | // Set the destination FixedDoubleArray's length and map. |
| 115 | Register map_root = array_size; |
| 116 | __ LoadRoot(map_root, Heap::kFixedDoubleArrayMapRootIndex); |
| 117 | __ SmiTag(x11, length); |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame] | 118 | __ Str(x11, FieldMemOperand(array, FixedDoubleArray::kLengthOffset)); |
| 119 | __ Str(map_root, FieldMemOperand(array, HeapObject::kMapOffset)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 120 | |
| 121 | __ Str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset)); |
| 122 | __ RecordWriteField(receiver, HeapObject::kMapOffset, target_map, scratch, |
| 123 | kLRHasBeenSaved, kDontSaveFPRegs, OMIT_REMEMBERED_SET, |
| 124 | OMIT_SMI_CHECK); |
| 125 | |
| 126 | // Replace receiver's backing store with newly created FixedDoubleArray. |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame] | 127 | __ Move(x10, array); |
| 128 | __ Str(array, FieldMemOperand(receiver, JSObject::kElementsOffset)); |
| 129 | __ RecordWriteField(receiver, JSObject::kElementsOffset, x10, scratch, |
| 130 | kLRHasBeenSaved, kDontSaveFPRegs, EMIT_REMEMBERED_SET, |
| 131 | OMIT_SMI_CHECK); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 132 | |
| 133 | // Prepare for conversion loop. |
| 134 | Register src_elements = x10; |
| 135 | Register dst_elements = x11; |
| 136 | Register dst_end = x12; |
| 137 | __ Add(src_elements, elements, FixedArray::kHeaderSize - kHeapObjectTag); |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame] | 138 | __ Add(dst_elements, array, FixedDoubleArray::kHeaderSize - kHeapObjectTag); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 139 | __ Add(dst_end, dst_elements, Operand(length, LSL, kDoubleSizeLog2)); |
| 140 | |
| 141 | FPRegister nan_d = d1; |
| 142 | __ Fmov(nan_d, rawbits_to_double(kHoleNanInt64)); |
| 143 | |
| 144 | Label entry, done; |
| 145 | __ B(&entry); |
| 146 | |
| 147 | __ Bind(&only_change_map); |
| 148 | __ Str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset)); |
| 149 | __ RecordWriteField(receiver, HeapObject::kMapOffset, target_map, scratch, |
| 150 | kLRHasNotBeenSaved, kDontSaveFPRegs, OMIT_REMEMBERED_SET, |
| 151 | OMIT_SMI_CHECK); |
| 152 | __ B(&done); |
| 153 | |
| 154 | // Call into runtime if GC is required. |
| 155 | __ Bind(&gc_required); |
| 156 | __ Pop(lr); |
| 157 | __ B(fail); |
| 158 | |
| 159 | // Iterate over the array, copying and coverting smis to doubles. If an |
| 160 | // element is non-smi, write a hole to the destination. |
| 161 | { |
| 162 | Label loop; |
| 163 | __ Bind(&loop); |
| 164 | __ Ldr(x13, MemOperand(src_elements, kPointerSize, PostIndex)); |
| 165 | __ SmiUntagToDouble(d0, x13, kSpeculativeUntag); |
| 166 | __ Tst(x13, kSmiTagMask); |
| 167 | __ Fcsel(d0, d0, nan_d, eq); |
| 168 | __ Str(d0, MemOperand(dst_elements, kDoubleSize, PostIndex)); |
| 169 | |
| 170 | __ Bind(&entry); |
| 171 | __ Cmp(dst_elements, dst_end); |
| 172 | __ B(lt, &loop); |
| 173 | } |
| 174 | |
| 175 | __ Pop(lr); |
| 176 | __ Bind(&done); |
| 177 | } |
| 178 | |
| 179 | |
| 180 | void ElementsTransitionGenerator::GenerateDoubleToObject( |
| 181 | MacroAssembler* masm, |
| 182 | Register receiver, |
| 183 | Register key, |
| 184 | Register value, |
| 185 | Register target_map, |
| 186 | AllocationSiteMode mode, |
| 187 | Label* fail) { |
| 188 | ASM_LOCATION("ElementsTransitionGenerator::GenerateDoubleToObject"); |
| 189 | Register elements = x4; |
| 190 | Register array_size = x6; |
| 191 | Register array = x7; |
| 192 | Register length = x5; |
| 193 | |
| 194 | // Verify input registers don't conflict with locals. |
| 195 | DCHECK(!AreAliased(receiver, key, value, target_map, |
| 196 | elements, array_size, array, length)); |
| 197 | |
| 198 | if (mode == TRACK_ALLOCATION_SITE) { |
| 199 | __ JumpIfJSArrayHasAllocationMemento(receiver, x10, x11, fail); |
| 200 | } |
| 201 | |
| 202 | // Check for empty arrays, which only require a map transition and no changes |
| 203 | // to the backing store. |
| 204 | Label only_change_map; |
| 205 | |
| 206 | __ Ldr(elements, FieldMemOperand(receiver, JSObject::kElementsOffset)); |
| 207 | __ JumpIfRoot(elements, Heap::kEmptyFixedArrayRootIndex, &only_change_map); |
| 208 | |
| 209 | __ Push(lr); |
| 210 | // TODO(all): These registers may not need to be pushed. Examine |
| 211 | // RecordWriteStub and check whether it's needed. |
| 212 | __ Push(target_map, receiver, key, value); |
| 213 | __ Ldrsw(length, UntagSmiFieldMemOperand(elements, |
| 214 | FixedArray::kLengthOffset)); |
| 215 | // Allocate new FixedArray. |
| 216 | Label gc_required; |
| 217 | __ Mov(array_size, FixedDoubleArray::kHeaderSize); |
| 218 | __ Add(array_size, array_size, Operand(length, LSL, kPointerSizeLog2)); |
| 219 | __ Allocate(array_size, array, x10, x11, &gc_required, NO_ALLOCATION_FLAGS); |
| 220 | |
| 221 | // Set destination FixedDoubleArray's length and map. |
| 222 | Register map_root = array_size; |
| 223 | __ LoadRoot(map_root, Heap::kFixedArrayMapRootIndex); |
| 224 | __ SmiTag(x11, length); |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame] | 225 | __ Str(x11, FieldMemOperand(array, FixedDoubleArray::kLengthOffset)); |
| 226 | __ Str(map_root, FieldMemOperand(array, HeapObject::kMapOffset)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 227 | |
| 228 | // Prepare for conversion loop. |
| 229 | Register src_elements = x10; |
| 230 | Register dst_elements = x11; |
| 231 | Register dst_end = x12; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 232 | Register the_hole = x14; |
| 233 | __ LoadRoot(the_hole, Heap::kTheHoleValueRootIndex); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 234 | __ Add(src_elements, elements, |
| 235 | FixedDoubleArray::kHeaderSize - kHeapObjectTag); |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame] | 236 | __ Add(dst_elements, array, FixedArray::kHeaderSize - kHeapObjectTag); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 237 | __ Add(dst_end, dst_elements, Operand(length, LSL, kPointerSizeLog2)); |
| 238 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 239 | // Allocating heap numbers in the loop below can fail and cause a jump to |
| 240 | // gc_required. We can't leave a partly initialized FixedArray behind, |
| 241 | // so pessimistically fill it with holes now. |
| 242 | Label initialization_loop, initialization_loop_entry; |
| 243 | __ B(&initialization_loop_entry); |
| 244 | __ bind(&initialization_loop); |
| 245 | __ Str(the_hole, MemOperand(dst_elements, kPointerSize, PostIndex)); |
| 246 | __ bind(&initialization_loop_entry); |
| 247 | __ Cmp(dst_elements, dst_end); |
| 248 | __ B(lt, &initialization_loop); |
| 249 | |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame] | 250 | __ Add(dst_elements, array, FixedArray::kHeaderSize - kHeapObjectTag); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 251 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 252 | Register heap_num_map = x15; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 253 | __ LoadRoot(heap_num_map, Heap::kHeapNumberMapRootIndex); |
| 254 | |
| 255 | Label entry; |
| 256 | __ B(&entry); |
| 257 | |
| 258 | // Call into runtime if GC is required. |
| 259 | __ Bind(&gc_required); |
| 260 | __ Pop(value, key, receiver, target_map); |
| 261 | __ Pop(lr); |
| 262 | __ B(fail); |
| 263 | |
| 264 | { |
| 265 | Label loop, convert_hole; |
| 266 | __ Bind(&loop); |
| 267 | __ Ldr(x13, MemOperand(src_elements, kPointerSize, PostIndex)); |
| 268 | __ Cmp(x13, kHoleNanInt64); |
| 269 | __ B(eq, &convert_hole); |
| 270 | |
| 271 | // Non-hole double, copy value into a heap number. |
| 272 | Register heap_num = length; |
| 273 | Register scratch = array_size; |
| 274 | Register scratch2 = elements; |
| 275 | __ AllocateHeapNumber(heap_num, &gc_required, scratch, scratch2, |
| 276 | x13, heap_num_map); |
| 277 | __ Mov(x13, dst_elements); |
| 278 | __ Str(heap_num, MemOperand(dst_elements, kPointerSize, PostIndex)); |
| 279 | __ RecordWrite(array, x13, heap_num, kLRHasBeenSaved, kDontSaveFPRegs, |
| 280 | EMIT_REMEMBERED_SET, OMIT_SMI_CHECK); |
| 281 | |
| 282 | __ B(&entry); |
| 283 | |
| 284 | // Replace the-hole NaN with the-hole pointer. |
| 285 | __ Bind(&convert_hole); |
| 286 | __ Str(the_hole, MemOperand(dst_elements, kPointerSize, PostIndex)); |
| 287 | |
| 288 | __ Bind(&entry); |
| 289 | __ Cmp(dst_elements, dst_end); |
| 290 | __ B(lt, &loop); |
| 291 | } |
| 292 | |
| 293 | __ Pop(value, key, receiver, target_map); |
| 294 | // Replace receiver's backing store with newly created and filled FixedArray. |
| 295 | __ Str(array, FieldMemOperand(receiver, JSObject::kElementsOffset)); |
| 296 | __ RecordWriteField(receiver, JSObject::kElementsOffset, array, x13, |
| 297 | kLRHasBeenSaved, kDontSaveFPRegs, EMIT_REMEMBERED_SET, |
| 298 | OMIT_SMI_CHECK); |
| 299 | __ Pop(lr); |
| 300 | |
| 301 | __ Bind(&only_change_map); |
| 302 | __ Str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset)); |
| 303 | __ RecordWriteField(receiver, HeapObject::kMapOffset, target_map, x13, |
| 304 | kLRHasNotBeenSaved, kDontSaveFPRegs, OMIT_REMEMBERED_SET, |
| 305 | OMIT_SMI_CHECK); |
| 306 | } |
| 307 | |
| 308 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 309 | CodeAgingHelper::CodeAgingHelper(Isolate* isolate) { |
| 310 | USE(isolate); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 311 | DCHECK(young_sequence_.length() == kNoCodeAgeSequenceLength); |
| 312 | // The sequence of instructions that is patched out for aging code is the |
| 313 | // following boilerplate stack-building prologue that is found both in |
| 314 | // FUNCTION and OPTIMIZED_FUNCTION code: |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 315 | PatchingAssembler patcher(isolate, young_sequence_.start(), |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 316 | young_sequence_.length() / kInstructionSize); |
| 317 | // The young sequence is the frame setup code for FUNCTION code types. It is |
| 318 | // generated by FullCodeGenerator::Generate. |
| 319 | MacroAssembler::EmitFrameSetupForCodeAgePatching(&patcher); |
| 320 | |
| 321 | #ifdef DEBUG |
| 322 | const int length = kCodeAgeStubEntryOffset / kInstructionSize; |
| 323 | DCHECK(old_sequence_.length() >= kCodeAgeStubEntryOffset); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 324 | PatchingAssembler patcher_old(isolate, old_sequence_.start(), length); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 325 | MacroAssembler::EmitCodeAgeSequence(&patcher_old, NULL); |
| 326 | #endif |
| 327 | } |
| 328 | |
| 329 | |
| 330 | #ifdef DEBUG |
| 331 | bool CodeAgingHelper::IsOld(byte* candidate) const { |
| 332 | return memcmp(candidate, old_sequence_.start(), kCodeAgeStubEntryOffset) == 0; |
| 333 | } |
| 334 | #endif |
| 335 | |
| 336 | |
| 337 | bool Code::IsYoungSequence(Isolate* isolate, byte* sequence) { |
| 338 | return MacroAssembler::IsYoungSequence(isolate, sequence); |
| 339 | } |
| 340 | |
| 341 | |
| 342 | void Code::GetCodeAgeAndParity(Isolate* isolate, byte* sequence, Age* age, |
| 343 | MarkingParity* parity) { |
| 344 | if (IsYoungSequence(isolate, sequence)) { |
| 345 | *age = kNoAgeCodeAge; |
| 346 | *parity = NO_MARKING_PARITY; |
| 347 | } else { |
| 348 | byte* target = sequence + kCodeAgeStubEntryOffset; |
| 349 | Code* stub = GetCodeFromTargetAddress(Memory::Address_at(target)); |
| 350 | GetCodeAgeAndParity(stub, age, parity); |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | |
| 355 | void Code::PatchPlatformCodeAge(Isolate* isolate, |
| 356 | byte* sequence, |
| 357 | Code::Age age, |
| 358 | MarkingParity parity) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 359 | PatchingAssembler patcher(isolate, sequence, |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 360 | kNoCodeAgeSequenceLength / kInstructionSize); |
| 361 | if (age == kNoAgeCodeAge) { |
| 362 | MacroAssembler::EmitFrameSetupForCodeAgePatching(&patcher); |
| 363 | } else { |
| 364 | Code * stub = GetCodeAgeStub(isolate, age, parity); |
| 365 | MacroAssembler::EmitCodeAgeSequence(&patcher, stub); |
| 366 | } |
| 367 | } |
| 368 | |
| 369 | |
| 370 | void StringCharLoadGenerator::Generate(MacroAssembler* masm, |
| 371 | Register string, |
| 372 | Register index, |
| 373 | Register result, |
| 374 | Label* call_runtime) { |
| 375 | DCHECK(string.Is64Bits() && index.Is32Bits() && result.Is64Bits()); |
| 376 | // Fetch the instance type of the receiver into result register. |
| 377 | __ Ldr(result, FieldMemOperand(string, HeapObject::kMapOffset)); |
| 378 | __ Ldrb(result, FieldMemOperand(result, Map::kInstanceTypeOffset)); |
| 379 | |
| 380 | // We need special handling for indirect strings. |
| 381 | Label check_sequential; |
| 382 | __ TestAndBranchIfAllClear(result, kIsIndirectStringMask, &check_sequential); |
| 383 | |
| 384 | // Dispatch on the indirect string shape: slice or cons. |
| 385 | Label cons_string; |
| 386 | __ TestAndBranchIfAllClear(result, kSlicedNotConsMask, &cons_string); |
| 387 | |
| 388 | // Handle slices. |
| 389 | Label indirect_string_loaded; |
| 390 | __ Ldr(result.W(), |
| 391 | UntagSmiFieldMemOperand(string, SlicedString::kOffsetOffset)); |
| 392 | __ Ldr(string, FieldMemOperand(string, SlicedString::kParentOffset)); |
| 393 | __ Add(index, index, result.W()); |
| 394 | __ B(&indirect_string_loaded); |
| 395 | |
| 396 | // Handle cons strings. |
| 397 | // Check whether the right hand side is the empty string (i.e. if |
| 398 | // this is really a flat string in a cons string). If that is not |
| 399 | // the case we would rather go to the runtime system now to flatten |
| 400 | // the string. |
| 401 | __ Bind(&cons_string); |
| 402 | __ Ldr(result, FieldMemOperand(string, ConsString::kSecondOffset)); |
| 403 | __ JumpIfNotRoot(result, Heap::kempty_stringRootIndex, call_runtime); |
| 404 | // Get the first of the two strings and load its instance type. |
| 405 | __ Ldr(string, FieldMemOperand(string, ConsString::kFirstOffset)); |
| 406 | |
| 407 | __ Bind(&indirect_string_loaded); |
| 408 | __ Ldr(result, FieldMemOperand(string, HeapObject::kMapOffset)); |
| 409 | __ Ldrb(result, FieldMemOperand(result, Map::kInstanceTypeOffset)); |
| 410 | |
| 411 | // Distinguish sequential and external strings. Only these two string |
| 412 | // representations can reach here (slices and flat cons strings have been |
| 413 | // reduced to the underlying sequential or external string). |
| 414 | Label external_string, check_encoding; |
| 415 | __ Bind(&check_sequential); |
| 416 | STATIC_ASSERT(kSeqStringTag == 0); |
| 417 | __ TestAndBranchIfAnySet(result, kStringRepresentationMask, &external_string); |
| 418 | |
| 419 | // Prepare sequential strings |
| 420 | STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize); |
| 421 | __ Add(string, string, SeqTwoByteString::kHeaderSize - kHeapObjectTag); |
| 422 | __ B(&check_encoding); |
| 423 | |
| 424 | // Handle external strings. |
| 425 | __ Bind(&external_string); |
| 426 | if (FLAG_debug_code) { |
| 427 | // Assert that we do not have a cons or slice (indirect strings) here. |
| 428 | // Sequential strings have already been ruled out. |
| 429 | __ Tst(result, kIsIndirectStringMask); |
| 430 | __ Assert(eq, kExternalStringExpectedButNotFound); |
| 431 | } |
| 432 | // Rule out short external strings. |
| 433 | STATIC_ASSERT(kShortExternalStringTag != 0); |
| 434 | // TestAndBranchIfAnySet can emit Tbnz. Do not use it because call_runtime |
| 435 | // can be bound far away in deferred code. |
| 436 | __ Tst(result, kShortExternalStringMask); |
| 437 | __ B(ne, call_runtime); |
| 438 | __ Ldr(string, FieldMemOperand(string, ExternalString::kResourceDataOffset)); |
| 439 | |
| 440 | Label one_byte, done; |
| 441 | __ Bind(&check_encoding); |
| 442 | STATIC_ASSERT(kTwoByteStringTag == 0); |
| 443 | __ TestAndBranchIfAnySet(result, kStringEncodingMask, &one_byte); |
| 444 | // Two-byte string. |
| 445 | __ Ldrh(result, MemOperand(string, index, SXTW, 1)); |
| 446 | __ B(&done); |
| 447 | __ Bind(&one_byte); |
| 448 | // One-byte string. |
| 449 | __ Ldrb(result, MemOperand(string, index, SXTW)); |
| 450 | __ Bind(&done); |
| 451 | } |
| 452 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 453 | #undef __ |
| 454 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 455 | } // namespace internal |
| 456 | } // namespace v8 |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 457 | |
| 458 | #endif // V8_TARGET_ARCH_ARM64 |