// Copyright 2021 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. #include "src/regexp/riscv/regexp-macro-assembler-riscv.h" #include "src/codegen/assembler-inl.h" #include "src/codegen/macro-assembler.h" #include "src/logging/log.h" #include "src/objects/objects-inl.h" #include "src/regexp/regexp-macro-assembler.h" #include "src/regexp/regexp-stack.h" #include "src/snapshot/embedded/embedded-data-inl.h" #include "src/strings/unicode.h" namespace v8 { namespace internal { /* clang-format off * This assembler uses the following register assignment convention * - s1 : Pointer to current Code object including heap object tag. * - s2 : Current position in input, as negative offset from end of string. * Please notice that this is the byte offset, not the character offset! * - s5 : Currently loaded character. Must be loaded using * LoadCurrentCharacter before using any of the dispatch methods. * - s6 : Points to tip of backtrack stack * - s7 : End of input (points to byte after last character in input). * - fp : Frame pointer. Used to access arguments, local variables and * RegExp registers. * - sp : Points to tip of C stack. * * The remaining registers are free for computations. * Each call to a public method should retain this convention. * * The stack will have the following structure: * * kStackFrameHeader * --- sp when called --- * - fp[72] ra Return from RegExp code (ra). kReturnAddress * - fp[64] s9, old-fp Old fp, callee saved(s9). * - fp[0..63] fp..s7 Callee-saved registers fp..s7. * --- frame pointer ---- * - fp[-8] Isolate* isolate (address of the current isolate) kIsolate * - fp[-16] direct_call (1 = direct call from JS, 0 = from runtime) kDirectCall * - fp[-24] output_size (may fit multiple sets of matches) kNumOutputRegisters * - fp[-32] int* output (int[num_saved_registers_], for output). kRegisterOutput * - fp[-40] end of input (address of end of string). kInputEnd * - fp[-48] start of input (address of first character in string). kInputStart * - fp[-56] start index (character index of start). kStartIndex * - fp[-64] void* input_string (location of a handle containing the string). kInputString * - fp[-72] success counter (only for global regexps to count matches). kSuccessfulCaptures * - fp[-80] Offset of location before start of input (effectively character kStringStartMinusOne * position -1). Used to initialize capture registers to a * non-position. * --------- The following output registers are 32-bit values. --------- * - fp[-88] register 0 (Only positions must be stored in the first kRegisterZero * - register 1 num_saved_registers_ registers) * - ... * - register num_registers-1 * --- sp --- * * The first num_saved_registers_ registers are initialized to point to * "character -1" in the string (i.e., char_size() bytes before the first * character of the string). The remaining registers start out as garbage. * * The data up to the return address must be placed there by the calling * code and the remaining arguments are passed in registers, e.g. by calling the * code entry as cast to a function with the signature: * int (*match)(String input_string, * int start_index, * Address start, * Address end, * int* output, * int output_size, * bool direct_call = false, * Isolate* isolate, * Address regexp); * The call is performed by NativeRegExpMacroAssembler::Execute() * (in regexp-macro-assembler.cc) via the GeneratedCode wrapper. * * clang-format on */ #define __ ACCESS_MASM(masm_) const int RegExpMacroAssemblerRISCV::kRegExpCodeSize; RegExpMacroAssemblerRISCV::RegExpMacroAssemblerRISCV(Isolate* isolate, Zone* zone, Mode mode, int registers_to_save) : NativeRegExpMacroAssembler(isolate, zone), masm_(std::make_unique( isolate, CodeObjectRequired::kYes, NewAssemblerBuffer(kRegExpCodeSize))), no_root_array_scope_(masm_.get()), mode_(mode), num_registers_(registers_to_save), num_saved_registers_(registers_to_save), entry_label_(), start_label_(), success_label_(), backtrack_label_(), exit_label_(), internal_failure_label_() { DCHECK_EQ(0, registers_to_save % 2); __ jmp(&entry_label_); // We'll write the entry code later. // If the code gets too big or corrupted, an internal exception will be // raised, and we will exit right away. __ bind(&internal_failure_label_); __ li(a0, Operand(FAILURE)); __ Ret(); __ bind(&start_label_); // And then continue from here. } RegExpMacroAssemblerRISCV::~RegExpMacroAssemblerRISCV() { // Unuse labels in case we throw away the assembler without calling GetCode. entry_label_.Unuse(); start_label_.Unuse(); success_label_.Unuse(); backtrack_label_.Unuse(); exit_label_.Unuse(); check_preempt_label_.Unuse(); stack_overflow_label_.Unuse(); internal_failure_label_.Unuse(); fallback_label_.Unuse(); } int RegExpMacroAssemblerRISCV::stack_limit_slack() { return RegExpStack::kStackLimitSlack; } void RegExpMacroAssemblerRISCV::AdvanceCurrentPosition(int by) { if (by != 0) { __ AddWord(current_input_offset(), current_input_offset(), Operand(by * char_size())); } } void RegExpMacroAssemblerRISCV::AdvanceRegister(int reg, int by) { DCHECK_LE(0, reg); DCHECK_GT(num_registers_, reg); if (by != 0) { __ LoadWord(a0, register_location(reg)); __ AddWord(a0, a0, Operand(by)); __ StoreWord(a0, register_location(reg)); } } void RegExpMacroAssemblerRISCV::Backtrack() { CheckPreemption(); if (has_backtrack_limit()) { Label next; __ LoadWord(a0, MemOperand(frame_pointer(), kBacktrackCount)); __ AddWord(a0, a0, Operand(1)); __ StoreWord(a0, MemOperand(frame_pointer(), kBacktrackCount)); __ BranchShort(&next, ne, a0, Operand(backtrack_limit())); // Backtrack limit exceeded. if (can_fallback()) { __ jmp(&fallback_label_); } else { // Can't fallback, so we treat it as a failed match. Fail(); } __ bind(&next); } // Pop Code offset from backtrack stack, add Code and jump to location. Pop(a0); __ AddWord(a0, a0, code_pointer()); __ Jump(a0); } void RegExpMacroAssemblerRISCV::Bind(Label* label) { __ bind(label); } void RegExpMacroAssemblerRISCV::CheckCharacter(uint32_t c, Label* on_equal) { BranchOrBacktrack(on_equal, eq, current_character(), Operand(c)); } void RegExpMacroAssemblerRISCV::CheckCharacterGT(base::uc16 limit, Label* on_greater) { BranchOrBacktrack(on_greater, gt, current_character(), Operand(limit)); } void RegExpMacroAssemblerRISCV::CheckAtStart(int cp_offset, Label* on_at_start) { __ LoadWord(a1, MemOperand(frame_pointer(), kStringStartMinusOne)); __ AddWord(a0, current_input_offset(), Operand(-char_size() + cp_offset * char_size())); BranchOrBacktrack(on_at_start, eq, a0, Operand(a1)); } void RegExpMacroAssemblerRISCV::CheckNotAtStart(int cp_offset, Label* on_not_at_start) { __ LoadWord(a1, MemOperand(frame_pointer(), kStringStartMinusOne)); __ AddWord(a0, current_input_offset(), Operand(-char_size() + cp_offset * char_size())); BranchOrBacktrack(on_not_at_start, ne, a0, Operand(a1)); } void RegExpMacroAssemblerRISCV::CheckCharacterLT(base::uc16 limit, Label* on_less) { BranchOrBacktrack(on_less, lt, current_character(), Operand(limit)); } void RegExpMacroAssemblerRISCV::CheckGreedyLoop(Label* on_equal) { Label backtrack_non_equal; __ Lw(a0, MemOperand(backtrack_stackpointer(), 0)); __ BranchShort(&backtrack_non_equal, ne, current_input_offset(), Operand(a0)); __ AddWord(backtrack_stackpointer(), backtrack_stackpointer(), Operand(kIntSize)); __ bind(&backtrack_non_equal); BranchOrBacktrack(on_equal, eq, current_input_offset(), Operand(a0)); } void RegExpMacroAssemblerRISCV::CallIsCharacterInRangeArray( const ZoneList* ranges) { static const int kNumArguments = 3; __ PrepareCallCFunction(kNumArguments, a0); __ mv(a0, current_character()); __ li(a1, Operand(GetOrAddRangeArray(ranges))); __ li(a2, Operand(ExternalReference::isolate_address(isolate()))); { // We have a frame (set up in GetCode), but the assembler doesn't know. FrameScope scope(masm_.get(), StackFrame::MANUAL); __ CallCFunction(ExternalReference::re_is_character_in_range_array(), kNumArguments); } __ li(code_pointer(), Operand(masm_->CodeObject())); } bool RegExpMacroAssemblerRISCV::CheckCharacterInRangeArray( const ZoneList* ranges, Label* on_in_range) { CallIsCharacterInRangeArray(ranges); BranchOrBacktrack(on_in_range, ne, a0, Operand(zero_reg)); return true; } bool RegExpMacroAssemblerRISCV::CheckCharacterNotInRangeArray( const ZoneList* ranges, Label* on_not_in_range) { CallIsCharacterInRangeArray(ranges); BranchOrBacktrack(on_not_in_range, eq, a0, Operand(zero_reg)); return true; } void RegExpMacroAssemblerRISCV::CheckNotBackReferenceIgnoreCase( int start_reg, bool read_backward, bool unicode, Label* on_no_match) { Label fallthrough; __ LoadWord(a0, register_location(start_reg)); // Index of start of capture. __ LoadWord(a1, register_location(start_reg + 1)); // Index of end of capture. __ SubWord(a1, a1, a0); // Length of capture. // At this point, the capture registers are either both set or both cleared. // If the capture length is zero, then the capture is either empty or cleared. // Fall through in both cases. __ BranchShort(&fallthrough, eq, a1, Operand(zero_reg)); if (read_backward) { __ LoadWord(t1, MemOperand(frame_pointer(), kStringStartMinusOne)); __ AddWord(t1, t1, a1); BranchOrBacktrack(on_no_match, le, current_input_offset(), Operand(t1)); } else { __ AddWord(t1, a1, current_input_offset()); // Check that there are enough characters left in the input. BranchOrBacktrack(on_no_match, gt, t1, Operand(zero_reg)); } if (mode_ == LATIN1) { Label success; Label fail; Label loop_check; // a0 - offset of start of capture. // a1 - length of capture. __ AddWord(a0, a0, Operand(end_of_input_address())); __ AddWord(a2, end_of_input_address(), Operand(current_input_offset())); if (read_backward) { __ SubWord(a2, a2, Operand(a1)); } __ AddWord(a1, a0, Operand(a1)); // a0 - Address of start of capture. // a1 - Address of end of capture. // a2 - Address of current input position. Label loop; __ bind(&loop); __ Lbu(a3, MemOperand(a0, 0)); __ addi(a0, a0, char_size()); __ Lbu(a4, MemOperand(a2, 0)); __ addi(a2, a2, char_size()); __ BranchShort(&loop_check, eq, a4, Operand(a3)); // Mismatch, try case-insensitive match (converting letters to lower-case). __ Or(a3, a3, Operand(0x20)); // Convert capture character to lower-case. __ Or(a4, a4, Operand(0x20)); // Also convert input character. __ BranchShort(&fail, ne, a4, Operand(a3)); __ SubWord(a3, a3, Operand('a')); __ BranchShort(&loop_check, Uless_equal, a3, Operand('z' - 'a')); // Latin-1: Check for values in range [224,254] but not 247. __ SubWord(a3, a3, Operand(224 - 'a')); // Weren't Latin-1 letters. __ BranchShort(&fail, Ugreater, a3, Operand(254 - 224)); // Check for 247. __ BranchShort(&fail, eq, a3, Operand(247 - 224)); __ bind(&loop_check); __ Branch(&loop, lt, a0, Operand(a1)); __ jmp(&success); __ bind(&fail); GoTo(on_no_match); __ bind(&success); // Compute new value of character position after the matched part. __ SubWord(current_input_offset(), a2, end_of_input_address()); if (read_backward) { __ LoadWord(t1, register_location(start_reg)); // Index of start of capture. __ LoadWord( a2, register_location(start_reg + 1)); // Index of end of capture. __ AddWord(current_input_offset(), current_input_offset(), Operand(t1)); __ SubWord(current_input_offset(), current_input_offset(), Operand(a2)); } } else { DCHECK(mode_ == UC16); int argument_count = 4; __ PrepareCallCFunction(argument_count, a2); // a0 - offset of start of capture. // a1 - length of capture. // Put arguments into arguments registers. // Parameters are // a0: Address byte_offset1 - Address captured substring's start. // a1: Address byte_offset2 - Address of current character position. // a2: size_t byte_length - length of capture in bytes(!). // a3: Isolate* isolate. // Address of start of capture. __ AddWord(a0, a0, Operand(end_of_input_address())); // Length of capture. __ mv(a2, a1); // Save length in callee-save register for use on return. __ mv(s3, a1); // Address of current input position. __ AddWord(a1, current_input_offset(), Operand(end_of_input_address())); if (read_backward) { __ SubWord(a1, a1, Operand(s3)); } // Isolate. __ li(a3, Operand(ExternalReference::isolate_address(masm_->isolate()))); { AllowExternalCallThatCantCauseGC scope(masm_.get()); ExternalReference function = unicode ? ExternalReference::re_case_insensitive_compare_unicode() : ExternalReference::re_case_insensitive_compare_non_unicode(); __ CallCFunction(function, argument_count); } // Check if function returned non-zero for success or zero for failure. BranchOrBacktrack(on_no_match, eq, a0, Operand(zero_reg)); // On success, increment position by length of capture. if (read_backward) { __ SubWord(current_input_offset(), current_input_offset(), Operand(s3)); } else { __ AddWord(current_input_offset(), current_input_offset(), Operand(s3)); } } __ bind(&fallthrough); } void RegExpMacroAssemblerRISCV::CheckNotBackReference(int start_reg, bool read_backward, Label* on_no_match) { Label fallthrough; // Find length of back-referenced capture. __ LoadWord(a0, register_location(start_reg)); __ LoadWord(a1, register_location(start_reg + 1)); __ SubWord(a1, a1, a0); // Length to check. // At this point, the capture registers are either both set or both cleared. // If the capture length is zero, then the capture is either empty or cleared. // Fall through in both cases. __ BranchShort(&fallthrough, eq, a1, Operand(zero_reg)); if (read_backward) { __ LoadWord(t1, MemOperand(frame_pointer(), kStringStartMinusOne)); __ AddWord(t1, t1, a1); BranchOrBacktrack(on_no_match, le, current_input_offset(), Operand(t1)); } else { __ AddWord(t1, a1, current_input_offset()); // Check that there are enough characters left in the input. BranchOrBacktrack(on_no_match, gt, t1, Operand(zero_reg)); } // Compute pointers to match string and capture string. __ AddWord(a0, a0, Operand(end_of_input_address())); __ AddWord(a2, end_of_input_address(), Operand(current_input_offset())); if (read_backward) { __ SubWord(a2, a2, Operand(a1)); } __ AddWord(a1, a1, Operand(a0)); Label loop; __ bind(&loop); if (mode_ == LATIN1) { __ Lbu(a3, MemOperand(a0, 0)); __ addi(a0, a0, char_size()); __ Lbu(a4, MemOperand(a2, 0)); __ addi(a2, a2, char_size()); } else { DCHECK(mode_ == UC16); __ Lhu(a3, MemOperand(a0, 0)); __ addi(a0, a0, char_size()); __ Lhu(a4, MemOperand(a2, 0)); __ addi(a2, a2, char_size()); } BranchOrBacktrack(on_no_match, ne, a3, Operand(a4)); __ Branch(&loop, lt, a0, Operand(a1)); // Move current character position to position after match. __ SubWord(current_input_offset(), a2, end_of_input_address()); if (read_backward) { __ LoadWord(t1, register_location(start_reg)); // Index of start of capture. __ LoadWord(a2, register_location(start_reg + 1)); // Index of end of capture. __ AddWord(current_input_offset(), current_input_offset(), Operand(t1)); __ SubWord(current_input_offset(), current_input_offset(), Operand(a2)); } __ bind(&fallthrough); } void RegExpMacroAssemblerRISCV::CheckNotCharacter(uint32_t c, Label* on_not_equal) { BranchOrBacktrack(on_not_equal, ne, current_character(), Operand(c)); } void RegExpMacroAssemblerRISCV::CheckCharacterAfterAnd(uint32_t c, uint32_t mask, Label* on_equal) { __ And(a0, current_character(), Operand(mask)); Operand rhs = (c == 0) ? Operand(zero_reg) : Operand(c); BranchOrBacktrack(on_equal, eq, a0, rhs); } void RegExpMacroAssemblerRISCV::CheckNotCharacterAfterAnd(uint32_t c, uint32_t mask, Label* on_not_equal) { __ And(a0, current_character(), Operand(mask)); Operand rhs = (c == 0) ? Operand(zero_reg) : Operand(c); BranchOrBacktrack(on_not_equal, ne, a0, rhs); } void RegExpMacroAssemblerRISCV::CheckNotCharacterAfterMinusAnd( base::uc16 c, base::uc16 minus, base::uc16 mask, Label* on_not_equal) { DCHECK_GT(String::kMaxUtf16CodeUnit, minus); __ SubWord(a0, current_character(), Operand(minus)); __ And(a0, a0, Operand(mask)); BranchOrBacktrack(on_not_equal, ne, a0, Operand(c)); } void RegExpMacroAssemblerRISCV::CheckCharacterInRange(base::uc16 from, base::uc16 to, Label* on_in_range) { __ SubWord(a0, current_character(), Operand(from)); // Unsigned lower-or-same condition. BranchOrBacktrack(on_in_range, Uless_equal, a0, Operand(to - from)); } void RegExpMacroAssemblerRISCV::CheckCharacterNotInRange( base::uc16 from, base::uc16 to, Label* on_not_in_range) { __ SubWord(a0, current_character(), Operand(from)); // Unsigned higher condition. BranchOrBacktrack(on_not_in_range, Ugreater, a0, Operand(to - from)); } void RegExpMacroAssemblerRISCV::CheckBitInTable(Handle table, Label* on_bit_set) { __ li(a0, Operand(table)); if (mode_ != LATIN1 || kTableMask != String::kMaxOneByteCharCode) { __ And(a1, current_character(), Operand(kTableSize - 1)); __ AddWord(a0, a0, a1); } else { __ AddWord(a0, a0, current_character()); } __ Lbu(a0, FieldMemOperand(a0, ByteArray::kHeaderSize)); BranchOrBacktrack(on_bit_set, ne, a0, Operand(zero_reg)); } bool RegExpMacroAssemblerRISCV::CheckSpecialClassRanges( StandardCharacterSet type, Label* on_no_match) { // Range checks (c in min..max) are generally implemented by an unsigned // (c - min) <= (max - min) check. switch (type) { case StandardCharacterSet::kWhitespace: // Match space-characters. if (mode_ == LATIN1) { // One byte space characters are '\t'..'\r', ' ' and \u00a0. Label success; __ BranchShort(&success, eq, current_character(), Operand(' ')); // Check range 0x09..0x0D. __ SubWord(a0, current_character(), Operand('\t')); __ BranchShort(&success, Uless_equal, a0, Operand('\r' - '\t')); // \u00a0 (NBSP). BranchOrBacktrack(on_no_match, ne, a0, Operand(0x00A0 - '\t')); __ bind(&success); return true; } return false; case StandardCharacterSet::kNotWhitespace: // The emitted code for generic character classes is good enough. return false; case StandardCharacterSet::kDigit: // Match Latin1 digits ('0'..'9'). __ SubWord(a0, current_character(), Operand('0')); BranchOrBacktrack(on_no_match, Ugreater, a0, Operand('9' - '0')); return true; case StandardCharacterSet::kNotDigit: // Match non Latin1-digits. __ SubWord(a0, current_character(), Operand('0')); BranchOrBacktrack(on_no_match, Uless_equal, a0, Operand('9' - '0')); return true; case StandardCharacterSet::kNotLineTerminator: { // Match non-newlines (not 0x0A('\n'), 0x0D('\r'), 0x2028 and 0x2029). __ Xor(a0, current_character(), Operand(0x01)); // See if current character is '\n'^1 or '\r'^1, i.e., 0x0B or 0x0C. __ SubWord(a0, a0, Operand(0x0B)); BranchOrBacktrack(on_no_match, Uless_equal, a0, Operand(0x0C - 0x0B)); if (mode_ == UC16) { // Compare original value to 0x2028 and 0x2029, using the already // computed (current_char ^ 0x01 - 0x0B). I.e., check for // 0x201D (0x2028 - 0x0B) or 0x201E. __ SubWord(a0, a0, Operand(0x2028 - 0x0B)); BranchOrBacktrack(on_no_match, Uless_equal, a0, Operand(1)); } return true; } case StandardCharacterSet::kLineTerminator: { // Match newlines (0x0A('\n'), 0x0D('\r'), 0x2028 and 0x2029). __ Xor(a0, current_character(), Operand(0x01)); // See if current character is '\n'^1 or '\r'^1, i.e., 0x0B or 0x0C. __ SubWord(a0, a0, Operand(0x0B)); if (mode_ == LATIN1) { BranchOrBacktrack(on_no_match, Ugreater, a0, Operand(0x0C - 0x0B)); } else { Label done; BranchOrBacktrack(&done, Uless_equal, a0, Operand(0x0C - 0x0B)); // Compare original value to 0x2028 and 0x2029, using the already // computed (current_char ^ 0x01 - 0x0B). I.e., check for // 0x201D (0x2028 - 0x0B) or 0x201E. __ SubWord(a0, a0, Operand(0x2028 - 0x0B)); BranchOrBacktrack(on_no_match, Ugreater, a0, Operand(1)); __ bind(&done); } return true; } case StandardCharacterSet::kWord: { if (mode_ != LATIN1) { // Table is 256 entries, so all Latin1 characters can be tested. BranchOrBacktrack(on_no_match, Ugreater, current_character(), Operand('z')); } ExternalReference map = ExternalReference::re_word_character_map(); __ li(a0, Operand(map)); __ AddWord(a0, a0, current_character()); __ Lbu(a0, MemOperand(a0, 0)); BranchOrBacktrack(on_no_match, eq, a0, Operand(zero_reg)); return true; } case StandardCharacterSet::kNotWord: { Label done; if (mode_ != LATIN1) { // Table is 256 entries, so all Latin1 characters can be tested. __ BranchShort(&done, Ugreater, current_character(), Operand('z')); } ExternalReference map = ExternalReference::re_word_character_map(); __ li(a0, Operand(map)); __ AddWord(a0, a0, current_character()); __ Lbu(a0, MemOperand(a0, 0)); BranchOrBacktrack(on_no_match, ne, a0, Operand(zero_reg)); if (mode_ != LATIN1) { __ bind(&done); } return true; } case StandardCharacterSet::kEverything: // Match any character. return true; // No custom implementation (yet): s(UC16), S(UC16). default: return false; } } void RegExpMacroAssemblerRISCV::Fail() { __ li(a0, Operand(FAILURE)); __ jmp(&exit_label_); } void RegExpMacroAssemblerRISCV::LoadRegExpStackPointerFromMemory(Register dst) { ExternalReference ref = ExternalReference::address_of_regexp_stack_stack_pointer(isolate()); __ li(dst, Operand(ref)); __ LoadWord(dst, MemOperand(dst)); } void RegExpMacroAssemblerRISCV::StoreRegExpStackPointerToMemory( Register src, Register scratch) { ExternalReference ref = ExternalReference::address_of_regexp_stack_stack_pointer(isolate()); __ li(scratch, Operand(ref)); __ StoreWord(src, MemOperand(scratch)); } void RegExpMacroAssemblerRISCV::PushRegExpBasePointer(Register stack_pointer, Register scratch) { ExternalReference ref = ExternalReference::address_of_regexp_stack_memory_top_address(isolate()); __ li(scratch, Operand(ref)); __ LoadWord(scratch, MemOperand(scratch)); __ SubWord(scratch, stack_pointer, scratch); __ StoreWord(scratch, MemOperand(frame_pointer(), kRegExpStackBasePointer)); } void RegExpMacroAssemblerRISCV::PopRegExpBasePointer(Register stack_pointer_out, Register scratch) { ExternalReference ref = ExternalReference::address_of_regexp_stack_memory_top_address(isolate()); __ LoadWord(stack_pointer_out, MemOperand(frame_pointer(), kRegExpStackBasePointer)); __ li(scratch, Operand(ref)); __ LoadWord(scratch, MemOperand(scratch)); __ AddWord(stack_pointer_out, stack_pointer_out, scratch); StoreRegExpStackPointerToMemory(stack_pointer_out, scratch); } Handle RegExpMacroAssemblerRISCV::GetCode(Handle source) { Label return_a0; if (masm_->has_exception()) { // If the code gets corrupted due to long regular expressions and lack of // space on trampolines, an internal exception flag is set. If this case // is detected, we will jump into exit sequence right away. __ bind_to(&entry_label_, internal_failure_label_.pos()); } else { // Finalize code - write the entry point code now we know how many // registers we need. // Entry code: __ bind(&entry_label_); // Tell the system that we have a stack frame. Because the type is MANUAL, // no is generated. FrameScope scope(masm_.get(), StackFrame::MANUAL); // Actually emit code to start a new stack frame. // Push arguments // Save callee-save registers. // Start new stack frame. // Store link register in existing stack-cell. // Order here should correspond to order of offset constants in header file. // TODO(plind): we save fp..s11, but ONLY use s3 here - use the regs // or dont save. RegList registers_to_retain = {fp, s1, s2, s3, s4, s5, s6, s7, s8 /*, s9, s10, s11*/}; DCHECK(registers_to_retain.Count() == kNumCalleeRegsToRetain); // The remaining arguments are passed in registers, e.g.by calling the code // entry as cast to a function with the signature: // // *int(*match)(String input_string, // a0 // int start_offset, // a1 // byte* input_start, // a2 // byte* input_end, // a3 // int* output, // a4 // int output_size, // a5 // int call_origin, // a6 // Isolate* isolate, // a7 // Address regexp); // on the stack RegList argument_registers = {a0, a1, a2, a3, a4, a5, a6, a7}; // According to MultiPush implementation, registers will be pushed in the // order of ra, fp, then s8, ..., s1, and finally a7,...a0 __ MultiPush(RegList{ra} | registers_to_retain | argument_registers); // Set frame pointer in space for it if this is not a direct call // from generated code. __ AddWord(frame_pointer(), sp, Operand(argument_registers.Count() * kSystemPointerSize)); static_assert(kSuccessfulCaptures == kInputString - kSystemPointerSize); __ mv(a0, zero_reg); __ push(a0); // Make room for success counter and initialize it to 0. static_assert(kStringStartMinusOne == kSuccessfulCaptures - kSystemPointerSize); __ push(a0); // Make room for "string start - 1" constant. static_assert(kBacktrackCount == kStringStartMinusOne - kSystemPointerSize); __ push(a0); // The backtrack counter static_assert(kRegExpStackBasePointer == kBacktrackCount - kSystemPointerSize); __ push(a0); // The regexp stack base ptr. // Initialize backtrack stack pointer. It must not be clobbered from here // on. Note the backtrack_stackpointer is callee-saved. static_assert(backtrack_stackpointer() == s7); LoadRegExpStackPointerFromMemory(backtrack_stackpointer()); // Store the regexp base pointer - we'll later restore it / write it to // memory when returning from this irregexp code object. PushRegExpBasePointer(backtrack_stackpointer(), a1); { // Check if we have space on the stack for registers. Label stack_limit_hit, stack_ok; ExternalReference stack_limit = ExternalReference::address_of_jslimit(masm_->isolate()); __ li(a0, Operand(stack_limit)); __ LoadWord(a0, MemOperand(a0)); __ SubWord(a0, sp, a0); // Handle it if the stack pointer is already below the stack limit. __ Branch(&stack_limit_hit, le, a0, Operand(zero_reg)); // Check if there is room for the variable number of registers above // the stack limit. __ Branch(&stack_ok, uge, a0, Operand(num_registers_ * kPointerSize)); // Exit with OutOfMemory exception. There is not enough space on the stack // for our working registers. __ li(a0, Operand(EXCEPTION)); __ jmp(&return_a0); __ bind(&stack_limit_hit); CallCheckStackGuardState(a0); // If returned value is non-zero, we exit with the returned value as // result. __ Branch(&return_a0, ne, a0, Operand(zero_reg)); __ bind(&stack_ok); } // Allocate space on stack for registers. __ SubWord(sp, sp, Operand(num_registers_ * kSystemPointerSize)); // Load string end. __ LoadWord(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd)); // Load input start. __ LoadWord(a0, MemOperand(frame_pointer(), kInputStart)); // Find negative length (offset of start relative to end). __ SubWord(current_input_offset(), a0, end_of_input_address()); // Set a0 to address of char before start of the input string // (effectively string position -1). __ LoadWord(a1, MemOperand(frame_pointer(), kStartIndex)); __ SubWord(a0, current_input_offset(), Operand(char_size())); __ slli(t1, a1, (mode_ == UC16) ? 1 : 0); __ SubWord(a0, a0, t1); // Store this value in a local variable, for use when clearing // position registers. __ StoreWord(a0, MemOperand(frame_pointer(), kStringStartMinusOne)); // Initialize code pointer register __ li(code_pointer(), Operand(masm_->CodeObject()), CONSTANT_SIZE); Label load_char_start_regexp; { Label start_regexp; // Load newline if index is at start, previous character otherwise. __ Branch(&load_char_start_regexp, ne, a1, Operand(zero_reg)); __ li(current_character(), Operand('\n')); __ jmp(&start_regexp); // Global regexp restarts matching here. __ bind(&load_char_start_regexp); // Load previous char as initial value of current character register. LoadCurrentCharacterUnchecked(-1, 1); __ bind(&start_regexp); } // Initialize on-stack registers. if (num_saved_registers_ > 0) { // Always is, if generated from a regexp. // Fill saved registers with initial value = start offset - 1. if (num_saved_registers_ > 8) { // Address of register 0. __ AddWord(a1, frame_pointer(), Operand(kRegisterZero)); __ li(a2, Operand(num_saved_registers_)); Label init_loop; __ bind(&init_loop); __ StoreWord(a0, MemOperand(a1)); __ AddWord(a1, a1, Operand(-kSystemPointerSize)); __ SubWord(a2, a2, Operand(1)); __ Branch(&init_loop, ne, a2, Operand(zero_reg)); } else { for (int i = 0; i < num_saved_registers_; i++) { __ StoreWord(a0, register_location(i)); } } } __ jmp(&start_label_); // Exit code: if (success_label_.is_linked()) { // Save captures when successful. __ bind(&success_label_); if (num_saved_registers_ > 0) { // Copy captures to output. __ LoadWord(a1, MemOperand(frame_pointer(), kInputStart)); __ LoadWord(a0, MemOperand(frame_pointer(), kRegisterOutput)); __ LoadWord(a2, MemOperand(frame_pointer(), kStartIndex)); __ SubWord(a1, end_of_input_address(), a1); // a1 is length of input in bytes. if (mode_ == UC16) { __ srli(a1, a1, 1); } // a1 is length of input in characters. __ AddWord(a1, a1, Operand(a2)); // a1 is length of string in characters. DCHECK_EQ(0, num_saved_registers_ % 2); // Always an even number of capture registers. This allows us to // unroll the loop once to add an operation between a load of a // register and the following use of that register. for (int i = 0; i < num_saved_registers_; i += 2) { __ LoadWord(a2, register_location(i)); __ LoadWord(a3, register_location(i + 1)); if (i == 0 && global_with_zero_length_check()) { // Keep capture start in a4 for the zero-length check later. __ mv(s3, a2); } if (mode_ == UC16) { __ srai(a2, a2, 1); __ AddWord(a2, a2, a1); __ srai(a3, a3, 1); __ AddWord(a3, a3, a1); } else { __ AddWord(a2, a1, Operand(a2)); __ AddWord(a3, a1, Operand(a3)); } // V8 expects the output to be an int32_t array. __ Sw(a2, MemOperand(a0)); __ AddWord(a0, a0, kIntSize); __ Sw(a3, MemOperand(a0)); __ AddWord(a0, a0, kIntSize); } } if (global()) { // Restart matching if the regular expression is flagged as global. __ LoadWord(a0, MemOperand(frame_pointer(), kSuccessfulCaptures)); __ LoadWord(a1, MemOperand(frame_pointer(), kNumOutputRegisters)); __ LoadWord(a2, MemOperand(frame_pointer(), kRegisterOutput)); // Increment success counter. __ AddWord(a0, a0, 1); __ StoreWord(a0, MemOperand(frame_pointer(), kSuccessfulCaptures)); // Capture results have been stored, so the number of remaining global // output registers is reduced by the number of stored captures. __ SubWord(a1, a1, num_saved_registers_); // Check whether we have enough room for another set of capture results. __ Branch(&return_a0, lt, a1, Operand(num_saved_registers_)); __ StoreWord(a1, MemOperand(frame_pointer(), kNumOutputRegisters)); // Advance the location for output. __ AddWord(a2, a2, num_saved_registers_ * kIntSize); __ StoreWord(a2, MemOperand(frame_pointer(), kRegisterOutput)); // Prepare a0 to initialize registers with its value in the next run. __ LoadWord(a0, MemOperand(frame_pointer(), kStringStartMinusOne)); // Restore the original regexp stack pointer value (effectively, pop the // stored base pointer). PopRegExpBasePointer(backtrack_stackpointer(), a2); if (global_with_zero_length_check()) { // Special case for zero-length matches. // s3: capture start index // Not a zero-length match, restart. __ Branch(&load_char_start_regexp, ne, current_input_offset(), Operand(s3)); // Offset from the end is zero if we already reached the end. __ Branch(&exit_label_, eq, current_input_offset(), Operand(zero_reg)); // Advance current position after a zero-length match. Label advance; __ bind(&advance); __ AddWord(current_input_offset(), current_input_offset(), Operand((mode_ == UC16) ? 2 : 1)); if (global_unicode()) CheckNotInSurrogatePair(0, &advance); } __ Branch(&load_char_start_regexp); } else { __ li(a0, Operand(SUCCESS)); } } // Exit and return a0. __ bind(&exit_label_); if (global()) { __ LoadWord(a0, MemOperand(frame_pointer(), kSuccessfulCaptures)); } __ bind(&return_a0); // Restore the original regexp stack pointer value (effectively, pop the // stored base pointer). PopRegExpBasePointer(backtrack_stackpointer(), a1); // Skip sp past regexp registers and local variables.. __ mv(sp, frame_pointer()); // Restore registers fp..s11 and return (restoring ra to pc). __ MultiPop(registers_to_retain | ra); __ Ret(); // Backtrack code (branch target for conditional backtracks). if (backtrack_label_.is_linked()) { __ bind(&backtrack_label_); Backtrack(); } Label exit_with_exception; // Preempt-code. if (check_preempt_label_.is_linked()) { SafeCallTarget(&check_preempt_label_); StoreRegExpStackPointerToMemory(backtrack_stackpointer(), a1); // Put regexp engine registers on stack. CallCheckStackGuardState(a0); // If returning non-zero, we should end execution with the given // result as return value. __ Branch(&return_a0, ne, a0, Operand(zero_reg)); LoadRegExpStackPointerFromMemory(backtrack_stackpointer()); // String might have moved: Reload end of string from frame. __ LoadWord(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd)); SafeReturn(); } // Backtrack stack overflow code. if (stack_overflow_label_.is_linked()) { SafeCallTarget(&stack_overflow_label_); // Call GrowStack(isolate). StoreRegExpStackPointerToMemory(backtrack_stackpointer(), a1); static constexpr int kNumArguments = 1; __ PrepareCallCFunction(kNumArguments, 0, a0); __ li(a0, ExternalReference::isolate_address(isolate())); ExternalReference grow_stack = ExternalReference::re_grow_stack(); __ CallCFunction(grow_stack, kNumArguments); // If nullptr is returned, we have failed to grow the stack, and must exit // with a stack-overflow exception. __ BranchShort(&exit_with_exception, eq, a0, Operand(zero_reg)); // Otherwise use return value as new stack pointer. __ mv(backtrack_stackpointer(), a0); // Restore saved registers and continue. SafeReturn(); } if (exit_with_exception.is_linked()) { // If any of the code above needed to exit with an exception. __ bind(&exit_with_exception); // Exit with Result EXCEPTION(-1) to signal thrown exception. __ li(a0, Operand(EXCEPTION)); __ jmp(&return_a0); } if (fallback_label_.is_linked()) { __ bind(&fallback_label_); __ li(a0, Operand(FALLBACK_TO_EXPERIMENTAL)); __ jmp(&return_a0); } } CodeDesc code_desc; masm_->GetCode(isolate(), &code_desc); Handle code = Factory::CodeBuilder(isolate(), code_desc, CodeKind::REGEXP) .set_self_reference(masm_->CodeObject()) .Build(); LOG(masm_->isolate(), RegExpCodeCreateEvent(Handle::cast(code), source)); return Handle::cast(code); } void RegExpMacroAssemblerRISCV::GoTo(Label* to) { if (to == nullptr) { Backtrack(); return; } __ jmp(to); return; } void RegExpMacroAssemblerRISCV::IfRegisterGE(int reg, int comparand, Label* if_ge) { __ LoadWord(a0, register_location(reg)); BranchOrBacktrack(if_ge, ge, a0, Operand(comparand)); } void RegExpMacroAssemblerRISCV::IfRegisterLT(int reg, int comparand, Label* if_lt) { __ LoadWord(a0, register_location(reg)); BranchOrBacktrack(if_lt, lt, a0, Operand(comparand)); } void RegExpMacroAssemblerRISCV::IfRegisterEqPos(int reg, Label* if_eq) { __ LoadWord(a0, register_location(reg)); BranchOrBacktrack(if_eq, eq, a0, Operand(current_input_offset())); } RegExpMacroAssembler::IrregexpImplementation RegExpMacroAssemblerRISCV::Implementation() { return kRISCVImplementation; } void RegExpMacroAssemblerRISCV::PopCurrentPosition() { Pop(current_input_offset()); } void RegExpMacroAssemblerRISCV::PopRegister(int register_index) { Pop(a0); __ StoreWord(a0, register_location(register_index)); } void RegExpMacroAssemblerRISCV::PushBacktrack(Label* label) { if (label->is_bound()) { int target = label->pos(); __ li(a0, Operand(target + Code::kHeaderSize - kHeapObjectTag)); } else { Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm_.get()); Label after_constant; __ BranchShort(&after_constant); int offset = masm_->pc_offset(); int cp_offset = offset + Code::kHeaderSize - kHeapObjectTag; __ emit(0); masm_->label_at_put(label, offset); __ bind(&after_constant); if (is_int16(cp_offset)) { __ Load32U(a0, MemOperand(code_pointer(), cp_offset)); } else { __ AddWord(a0, code_pointer(), cp_offset); __ Load32U(a0, MemOperand(a0, 0)); } } Push(a0); CheckStackLimit(); } void RegExpMacroAssemblerRISCV::PushCurrentPosition() { Push(current_input_offset()); } void RegExpMacroAssemblerRISCV::PushRegister(int register_index, StackCheckFlag check_stack_limit) { __ LoadWord(a0, register_location(register_index)); Push(a0); if (check_stack_limit) CheckStackLimit(); } void RegExpMacroAssemblerRISCV::ReadCurrentPositionFromRegister(int reg) { __ LoadWord(current_input_offset(), register_location(reg)); } void RegExpMacroAssemblerRISCV::WriteStackPointerToRegister(int reg) { ExternalReference ref = ExternalReference::address_of_regexp_stack_memory_top_address(isolate()); __ li(a0, ref); __ LoadWord(a0, MemOperand(a0)); __ SubWord(a0, backtrack_stackpointer(), a0); __ Sw(a0, register_location(reg)); } void RegExpMacroAssemblerRISCV::ReadStackPointerFromRegister(int reg) { ExternalReference ref = ExternalReference::address_of_regexp_stack_memory_top_address(isolate()); __ li(a1, ref); __ LoadWord(a1, MemOperand(a1)); __ Lw(backtrack_stackpointer(), register_location(reg)); __ AddWord(backtrack_stackpointer(), backtrack_stackpointer(), a1); } void RegExpMacroAssemblerRISCV::SetCurrentPositionFromEnd(int by) { Label after_position; __ BranchShort(&after_position, ge, current_input_offset(), Operand(-by * char_size())); __ li(current_input_offset(), -by * char_size()); // On RegExp code entry (where this operation is used), the character before // the current position is expected to be already loaded. // We have advanced the position, so it's safe to read backwards. LoadCurrentCharacterUnchecked(-1, 1); __ bind(&after_position); } void RegExpMacroAssemblerRISCV::SetRegister(int register_index, int to) { DCHECK(register_index >= num_saved_registers_); // Reserved for positions! __ li(a0, Operand(to)); __ StoreWord(a0, register_location(register_index)); } bool RegExpMacroAssemblerRISCV::Succeed() { __ jmp(&success_label_); return global(); } void RegExpMacroAssemblerRISCV::WriteCurrentPositionToRegister(int reg, int cp_offset) { if (cp_offset == 0) { __ StoreWord(current_input_offset(), register_location(reg)); } else { __ AddWord(a0, current_input_offset(), Operand(cp_offset * char_size())); __ StoreWord(a0, register_location(reg)); } } void RegExpMacroAssemblerRISCV::ClearRegisters(int reg_from, int reg_to) { DCHECK(reg_from <= reg_to); __ LoadWord(a0, MemOperand(frame_pointer(), kStringStartMinusOne)); for (int reg = reg_from; reg <= reg_to; reg++) { __ StoreWord(a0, register_location(reg)); } } #ifdef RISCV_HAS_NO_UNALIGNED bool RegExpMacroAssemblerRISCV::CanReadUnaligned() const { return false; } #endif // Private methods: void RegExpMacroAssemblerRISCV::CallCheckStackGuardState(Register scratch) { DCHECK(!isolate()->IsGeneratingEmbeddedBuiltins()); DCHECK(!masm_->options().isolate_independent_code); int stack_alignment = base::OS::ActivationFrameAlignment(); // Align the stack pointer and save the original sp value on the stack. __ mv(scratch, sp); __ SubWord(sp, sp, Operand(kSystemPointerSize)); DCHECK(base::bits::IsPowerOfTwo(stack_alignment)); __ And(sp, sp, Operand(-stack_alignment)); __ StoreWord(scratch, MemOperand(sp)); __ mv(a2, frame_pointer()); // Code of self. __ li(a1, Operand(masm_->CodeObject()), CONSTANT_SIZE); // We need to make room for the return address on the stack. DCHECK(IsAligned(stack_alignment, kSystemPointerSize)); __ SubWord(sp, sp, Operand(stack_alignment)); // The stack pointer now points to cell where the return address will be // written. Arguments are in registers, meaning we treat the return address as // argument 5. Since DirectCEntry will handle allocating space for the C // argument slots, we don't need to care about that here. This is how the // stack will look (sp meaning the value of sp at this moment): // [sp + 3] - empty slot if needed for alignment. // [sp + 2] - saved sp. // [sp + 1] - second word reserved for return value. // [sp + 0] - first word reserved for return value. // a0 will point to the return address, placed by DirectCEntry. __ mv(a0, sp); ExternalReference stack_guard_check = ExternalReference::re_check_stack_guard_state(); __ li(t6, Operand(stack_guard_check)); EmbeddedData d = EmbeddedData::FromBlob(); CHECK(Builtins::IsIsolateIndependent(Builtin::kDirectCEntry)); Address entry = d.InstructionStartOfBuiltin(Builtin::kDirectCEntry); __ li(kScratchReg, Operand(entry, RelocInfo::OFF_HEAP_TARGET)); __ Call(kScratchReg); // DirectCEntry allocated space for the C argument slots so we have to // drop them with the return address from the stack with loading saved sp. // At this point stack must look: // [sp + 7] - empty slot if needed for alignment. // [sp + 6] - saved sp. // [sp + 5] - second word reserved for return value. // [sp + 4] - first word reserved for return value. // [sp + 3] - C argument slot. // [sp + 2] - C argument slot. // [sp + 1] - C argument slot. // [sp + 0] - C argument slot. __ LoadWord(sp, MemOperand(sp, stack_alignment + kCArgsSlotsSize)); __ li(code_pointer(), Operand(masm_->CodeObject())); } // Helper function for reading a value out of a stack frame. template static T& frame_entry(Address re_frame, int frame_offset) { return reinterpret_cast(Memory(re_frame + frame_offset)); } template static T* frame_entry_address(Address re_frame, int frame_offset) { return reinterpret_cast(re_frame + frame_offset); } int64_t RegExpMacroAssemblerRISCV::CheckStackGuardState(Address* return_address, Address raw_code, Address re_frame) { Code re_code = Code::cast(Object(raw_code)); return NativeRegExpMacroAssembler::CheckStackGuardState( frame_entry(re_frame, kIsolate), static_cast(frame_entry(re_frame, kStartIndex)), static_cast( frame_entry(re_frame, kDirectCall)), return_address, re_code, frame_entry_address
(re_frame, kInputString), frame_entry_address(re_frame, kInputStart), frame_entry_address(re_frame, kInputEnd)); } MemOperand RegExpMacroAssemblerRISCV::register_location(int register_index) { DCHECK(register_index < (1 << 30)); if (num_registers_ <= register_index) { num_registers_ = register_index + 1; } return MemOperand(frame_pointer(), kRegisterZero - register_index * kSystemPointerSize); } void RegExpMacroAssemblerRISCV::CheckPosition(int cp_offset, Label* on_outside_input) { if (cp_offset >= 0) { BranchOrBacktrack(on_outside_input, ge, current_input_offset(), Operand(-cp_offset * char_size())); } else { __ LoadWord(a1, MemOperand(frame_pointer(), kStringStartMinusOne)); __ AddWord(a0, current_input_offset(), Operand(cp_offset * char_size())); BranchOrBacktrack(on_outside_input, le, a0, Operand(a1)); } } void RegExpMacroAssemblerRISCV::BranchOrBacktrack(Label* to, Condition condition, Register rs, const Operand& rt) { if (condition == al) { // Unconditional. if (to == nullptr) { Backtrack(); return; } __ jmp(to); return; } if (to == nullptr) { __ Branch(&backtrack_label_, condition, rs, rt); return; } __ Branch(to, condition, rs, rt); } void RegExpMacroAssemblerRISCV::SafeCall(Label* to, Condition cond, Register rs, const Operand& rt) { __ BranchAndLink(to, cond, rs, rt); } void RegExpMacroAssemblerRISCV::SafeReturn() { __ pop(ra); __ AddWord(t1, ra, Operand(masm_->CodeObject())); __ Jump(t1); } void RegExpMacroAssemblerRISCV::SafeCallTarget(Label* name) { __ bind(name); __ SubWord(ra, ra, Operand(masm_->CodeObject())); __ push(ra); } void RegExpMacroAssemblerRISCV::Push(Register source) { DCHECK(source != backtrack_stackpointer()); __ AddWord(backtrack_stackpointer(), backtrack_stackpointer(), Operand(-kIntSize)); __ Sw(source, MemOperand(backtrack_stackpointer())); } void RegExpMacroAssemblerRISCV::Pop(Register target) { DCHECK(target != backtrack_stackpointer()); __ Lw(target, MemOperand(backtrack_stackpointer())); __ AddWord(backtrack_stackpointer(), backtrack_stackpointer(), kIntSize); } void RegExpMacroAssemblerRISCV::CheckPreemption() { // Check for preemption. ExternalReference stack_limit = ExternalReference::address_of_jslimit(masm_->isolate()); __ li(a0, Operand(stack_limit)); __ LoadWord(a0, MemOperand(a0)); SafeCall(&check_preempt_label_, Uless_equal, sp, Operand(a0)); } void RegExpMacroAssemblerRISCV::CheckStackLimit() { ExternalReference stack_limit = ExternalReference::address_of_regexp_stack_limit_address( masm_->isolate()); __ li(a0, Operand(stack_limit)); __ LoadWord(a0, MemOperand(a0)); SafeCall(&stack_overflow_label_, Uless_equal, backtrack_stackpointer(), Operand(a0)); } void RegExpMacroAssemblerRISCV::LoadCurrentCharacterUnchecked(int cp_offset, int characters) { Register offset = current_input_offset(); if (cp_offset != 0) { // kScratchReg2 is not being used to store the capture start index at this // point. __ AddWord(kScratchReg2, current_input_offset(), Operand(cp_offset * char_size())); offset = kScratchReg2; } // If unaligned load/stores are not supported then this function must only // be used to load a single character at a time. if (!CanReadUnaligned()) { DCHECK_EQ(1, characters); } if (mode_ == LATIN1) { if (characters == 4) { __ AddWord(kScratchReg, end_of_input_address(), offset); __ Load32U(current_character(), MemOperand(kScratchReg)); } else if (characters == 2) { __ AddWord(kScratchReg, end_of_input_address(), offset); __ Lhu(current_character(), MemOperand(kScratchReg)); } else { DCHECK_EQ(1, characters); __ AddWord(kScratchReg, end_of_input_address(), offset); __ Lbu(current_character(), MemOperand(kScratchReg)); } } else { DCHECK_EQ(UC16, mode_); if (characters == 2) { __ AddWord(kScratchReg, end_of_input_address(), offset); __ Load32U(current_character(), MemOperand(kScratchReg)); } else { DCHECK_EQ(1, characters); __ AddWord(kScratchReg, end_of_input_address(), offset); __ Lhu(current_character(), MemOperand(kScratchReg)); } } } #undef __ } // namespace internal } // namespace v8