}
+void StringStubBase::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
+ Register c1,
+ Register c2,
+ Register scratch1,
+ Register scratch2,
+ Register scratch3,
+ Register scratch4,
+ Register scratch5,
+ Label* not_found) {
+ // Register scratch3 is the general scratch register in this function.
+ Register scratch = scratch3;
+
+ // Make sure that both characters are not digits as such strings has a
+ // different hash algorithm. Don't try to look for these in the symbol table.
+ Label not_array_index;
+ __ sub(scratch, c1, Operand(static_cast<int>('0')));
+ __ cmp(scratch, Operand(static_cast<int>('9' - '0')));
+ __ b(hi, ¬_array_index);
+ __ sub(scratch, c2, Operand(static_cast<int>('0')));
+ __ cmp(scratch, Operand(static_cast<int>('9' - '0')));
+
+ // If check failed combine both characters into single halfword.
+ // This is required by the contract of the method: code at the
+ // not_found branch expects this combination in c1 register
+ __ orr(c1, c1, Operand(c2, LSL, kBitsPerByte), LeaveCC, ls);
+ __ b(ls, not_found);
+
+ __ bind(¬_array_index);
+ // Calculate the two character string hash.
+ Register hash = scratch1;
+ GenerateHashInit(masm, hash, c1);
+ GenerateHashAddCharacter(masm, hash, c2);
+ GenerateHashGetHash(masm, hash);
+
+ // Collect the two characters in a register.
+ Register chars = c1;
+ __ orr(chars, chars, Operand(c2, LSL, kBitsPerByte));
+
+ // chars: two character string, char 1 in byte 0 and char 2 in byte 1.
+ // hash: hash of two character string.
+
+ // Load symbol table
+ // Load address of first element of the symbol table.
+ Register symbol_table = c2;
+ __ LoadRoot(symbol_table, Heap::kSymbolTableRootIndex);
+
+ // Load undefined value
+ Register undefined = scratch4;
+ __ LoadRoot(undefined, Heap::kUndefinedValueRootIndex);
+
+ // Calculate capacity mask from the symbol table capacity.
+ Register mask = scratch2;
+ __ ldr(mask, FieldMemOperand(symbol_table, SymbolTable::kCapacityOffset));
+ __ mov(mask, Operand(mask, ASR, 1));
+ __ sub(mask, mask, Operand(1));
+
+ // Calculate untagged address of the first element of the symbol table.
+ Register first_symbol_table_element = symbol_table;
+ __ add(first_symbol_table_element, symbol_table,
+ Operand(SymbolTable::kElementsStartOffset - kHeapObjectTag));
+
+ // Registers
+ // chars: two character string, char 1 in byte 0 and char 2 in byte 1.
+ // hash: hash of two character string
+ // mask: capacity mask
+ // first_symbol_table_element: address of the first element of
+ // the symbol table
+ // scratch: -
+
+ // Perform a number of probes in the symbol table.
+ static const int kProbes = 4;
+ Label found_in_symbol_table;
+ Label next_probe[kProbes];
+ for (int i = 0; i < kProbes; i++) {
+ Register candidate = scratch5; // Scratch register contains candidate.
+
+ // Calculate entry in symbol table.
+ if (i > 0) {
+ __ add(candidate, hash, Operand(SymbolTable::GetProbeOffset(i)));
+ } else {
+ __ mov(candidate, hash);
+ }
+
+ __ and_(candidate, candidate, Operand(mask));
+
+ // Load the entry from the symble table.
+ ASSERT_EQ(1, SymbolTable::kEntrySize);
+ __ ldr(candidate,
+ MemOperand(first_symbol_table_element,
+ candidate,
+ LSL,
+ kPointerSizeLog2));
+
+ // If entry is undefined no string with this hash can be found.
+ __ cmp(candidate, undefined);
+ __ b(eq, not_found);
+
+ // If length is not 2 the string is not a candidate.
+ __ ldr(scratch, FieldMemOperand(candidate, String::kLengthOffset));
+ __ cmp(scratch, Operand(2));
+ __ b(ne, &next_probe[i]);
+
+ // Check that the candidate is a non-external ascii string.
+ __ ldr(scratch, FieldMemOperand(candidate, HeapObject::kMapOffset));
+ __ ldrb(scratch, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
+ __ JumpIfInstanceTypeIsNotSequentialAscii(scratch, scratch,
+ &next_probe[i]);
+
+ // Check if the two characters match.
+ // Assumes that word load is little endian.
+ __ ldrh(scratch, FieldMemOperand(candidate, SeqAsciiString::kHeaderSize));
+ __ cmp(chars, scratch);
+ __ b(eq, &found_in_symbol_table);
+ __ bind(&next_probe[i]);
+ }
+
+ // No matching 2 character string found by probing.
+ __ jmp(not_found);
+
+ // Scratch register contains result when we fall through to here.
+ Register result = scratch;
+ __ bind(&found_in_symbol_table);
+ if (!result.is(r0)) {
+ __ mov(r0, result);
+ }
+}
+
+
+void StringStubBase::GenerateHashInit(MacroAssembler* masm,
+ Register hash,
+ Register character) {
+ // hash = character + (character << 10);
+ __ add(hash, character, Operand(character, LSL, 10));
+ // hash ^= hash >> 6;
+ __ eor(hash, hash, Operand(hash, ASR, 6));
+}
+
+
+void StringStubBase::GenerateHashAddCharacter(MacroAssembler* masm,
+ Register hash,
+ Register character) {
+ // hash += character;
+ __ add(hash, hash, Operand(character));
+ // hash += hash << 10;
+ __ add(hash, hash, Operand(hash, LSL, 10));
+ // hash ^= hash >> 6;
+ __ eor(hash, hash, Operand(hash, ASR, 6));
+}
+
+
+void StringStubBase::GenerateHashGetHash(MacroAssembler* masm,
+ Register hash) {
+ // hash += hash << 3;
+ __ add(hash, hash, Operand(hash, LSL, 3));
+ // hash ^= hash >> 11;
+ __ eor(hash, hash, Operand(hash, ASR, 11));
+ // hash += hash << 15;
+ __ add(hash, hash, Operand(hash, LSL, 15), SetCC);
+
+ // if (hash == 0) hash = 27;
+ __ mov(hash, Operand(27), LeaveCC, nz);
+}
+
+
void SubStringStub::Generate(MacroAssembler* masm) {
Label runtime;
__ sub(r2, r2, Operand(r3), SetCC);
__ b(mi, &runtime); // Fail if from > to.
- // Handle sub-strings of length 2 and less in the runtime system.
+ // Special handling of sub-strings of length 1 and 2. One character strings
+ // are handled in the runtime system (looked up in the single character
+ // cache). Two character strings are looked for in the symbol cache.
__ cmp(r2, Operand(2));
- __ b(le, &runtime);
+ __ b(lt, &runtime);
// r2: length
+ // r3: from index (untaged smi)
// r6: from (smi)
// r7: to (smi)
// r1: instance type
// r2: length
+ // r3: from index (untaged smi)
// r5: string
// r6: from (smi)
// r7: to (smi)
// r1: instance type.
// r2: length
+ // r3: from index (untaged smi)
// r5: string
// r6: from (smi)
// r7: to (smi)
// r1: instance type.
// r2: result string length.
+ // r3: from index (untaged smi)
// r5: string.
// r6: from offset (smi)
// Check for flat ascii string.
ASSERT_EQ(0, kTwoByteStringTag);
__ b(eq, &non_ascii_flat);
+ Label result_longer_than_two;
+ __ cmp(r2, Operand(2));
+ __ b(gt, &result_longer_than_two);
+
+ // Sub string of length 2 requested.
+ // Get the two characters forming the sub string.
+ __ add(r5, r5, Operand(r3));
+ __ ldrb(r3, FieldMemOperand(r5, SeqAsciiString::kHeaderSize));
+ __ ldrb(r4, FieldMemOperand(r5, SeqAsciiString::kHeaderSize + 1));
+
+ // Try to lookup two character string in symbol table.
+ Label make_two_character_string;
+ GenerateTwoCharacterSymbolTableProbe(masm, r3, r4, r1, r5, r6, r7, r9,
+ &make_two_character_string);
+ __ IncrementCounter(&Counters::sub_string_native, 1, r3, r4);
+ __ add(sp, sp, Operand(3 * kPointerSize));
+ __ Ret();
+
+ // r2: result string length.
+ // r3: two characters combined into halfword in little endian byte order.
+ __ bind(&make_two_character_string);
+ __ AllocateAsciiString(r0, r2, r4, r5, r9, &runtime);
+ __ strh(r3, FieldMemOperand(r0, SeqAsciiString::kHeaderSize));
+ __ IncrementCounter(&Counters::sub_string_native, 1, r3, r4);
+ __ add(sp, sp, Operand(3 * kPointerSize));
+ __ Ret();
+
+ __ bind(&result_longer_than_two);
+
// Allocate the result.
__ AllocateAsciiString(r0, r2, r3, r4, r1, &runtime);
// r4: first string instance type (if string_check_)
// r5: second string instance type (if string_check_)
// Look at the length of the result of adding the two strings.
- Label string_add_flat_result;
+ Label string_add_flat_result, longer_than_two;
// Adding two lengths can't overflow.
ASSERT(String::kMaxLength * 2 > String::kMaxLength);
__ add(r6, r2, Operand(r3));
// Use the runtime system when adding two one character strings, as it
// contains optimizations for this specific case using the symbol table.
__ cmp(r6, Operand(2));
- __ b(eq, &string_add_runtime);
+ __ b(ne, &longer_than_two);
+
+ // Check that both strings are non-external ascii strings.
+ if (!string_check_) {
+ __ ldr(r4, FieldMemOperand(r0, HeapObject::kMapOffset));
+ __ ldr(r5, FieldMemOperand(r1, HeapObject::kMapOffset));
+ __ ldrb(r4, FieldMemOperand(r4, Map::kInstanceTypeOffset));
+ __ ldrb(r5, FieldMemOperand(r5, Map::kInstanceTypeOffset));
+ }
+ __ JumpIfBothInstanceTypesAreNotSequentialAscii(r4, r5, r6, r7,
+ &string_add_runtime);
+
+ // Get the two characters forming the sub string.
+ __ ldrb(r2, FieldMemOperand(r0, SeqAsciiString::kHeaderSize));
+ __ ldrb(r3, FieldMemOperand(r1, SeqAsciiString::kHeaderSize));
+
+ // Try to lookup two character string in symbol table. If it is not found
+ // just allocate a new one.
+ Label make_two_character_string;
+ GenerateTwoCharacterSymbolTableProbe(masm, r2, r3, r6, r7, r4, r5, r9,
+ &make_two_character_string);
+ __ IncrementCounter(&Counters::string_add_native, 1, r2, r3);
+ __ add(sp, sp, Operand(2 * kPointerSize));
+ __ Ret();
+
+ __ bind(&make_two_character_string);
+ // Resulting string has length 2 and first chars of two strings
+ // are combined into single halfword in r2 register.
+ // So we can fill resulting string without two loops by a single
+ // halfword store instruction (which assumes that processor is
+ // in a little endian mode)
+ __ mov(r6, Operand(2));
+ __ AllocateAsciiString(r0, r6, r4, r5, r9, &string_add_runtime);
+ __ strh(r2, FieldMemOperand(r0, SeqAsciiString::kHeaderSize));
+ __ IncrementCounter(&Counters::string_add_native, 1, r2, r3);
+ __ add(sp, sp, Operand(2 * kPointerSize));
+ __ Ret();
+
+ __ bind(&longer_than_two);
// Check if resulting string will be flat.
__ cmp(r6, Operand(String::kMinNonFlatLength));
__ b(lt, &string_add_flat_result);
// Both strings are sequential ASCII strings. We also know that they are
// short (since the sum of the lengths is less than kMinNonFlatLength).
+ // r6: length of resulting flat string
__ AllocateAsciiString(r7, r6, r4, r5, r9, &string_add_runtime);
// Locate first character of result.
__ add(r6, r7, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
Register scratch4,
Register scratch5,
int flags);
+
+
+ // Probe the symbol table for a two character string. If the string is
+ // not found by probing a jump to the label not_found is performed. This jump
+ // does not guarantee that the string is not in the symbol table. If the
+ // string is found the code falls through with the string in register r0.
+ // Contents of both c1 and c2 registers are modified. At the exit c1 is
+ // guaranteed to contain halfword with low and high bytes equal to
+ // initial contents of c1 and c2 respectively.
+ void GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
+ Register c1,
+ Register c2,
+ Register scratch1,
+ Register scratch2,
+ Register scratch3,
+ Register scratch4,
+ Register scratch5,
+ Label* not_found);
+
+ // Generate string hash.
+ void GenerateHashInit(MacroAssembler* masm,
+ Register hash,
+ Register character);
+
+ void GenerateHashAddCharacter(MacroAssembler* masm,
+ Register hash,
+ Register character);
+
+ void GenerateHashGetHash(MacroAssembler* masm,
+ Register hash);
};
ldr(scratch2, FieldMemOperand(second, HeapObject::kMapOffset));
ldrb(scratch1, FieldMemOperand(scratch1, Map::kInstanceTypeOffset));
ldrb(scratch2, FieldMemOperand(scratch2, Map::kInstanceTypeOffset));
- int kFlatAsciiStringMask =
- kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask;
- int kFlatAsciiStringTag = ASCII_STRING_TYPE;
- and_(scratch1, scratch1, Operand(kFlatAsciiStringMask));
- and_(scratch2, scratch2, Operand(kFlatAsciiStringMask));
- cmp(scratch1, Operand(kFlatAsciiStringTag));
- // Ignore second test if first test failed.
- cmp(scratch2, Operand(kFlatAsciiStringTag), eq);
- b(ne, failure);
+
+ JumpIfBothInstanceTypesAreNotSequentialAscii(scratch1,
+ scratch2,
+ scratch1,
+ scratch2,
+ failure);
}
void MacroAssembler::JumpIfNotBothSequentialAsciiStrings(Register first,
}
+void MacroAssembler::JumpIfBothInstanceTypesAreNotSequentialAscii(
+ Register first,
+ Register second,
+ Register scratch1,
+ Register scratch2,
+ Label* failure) {
+ int kFlatAsciiStringMask =
+ kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask;
+ int kFlatAsciiStringTag = ASCII_STRING_TYPE;
+ and_(scratch1, first, Operand(kFlatAsciiStringMask));
+ and_(scratch2, second, Operand(kFlatAsciiStringMask));
+ cmp(scratch1, Operand(kFlatAsciiStringTag));
+ // Ignore second test if first test failed.
+ cmp(scratch2, Operand(kFlatAsciiStringTag), eq);
+ b(ne, failure);
+}
+
+
+void MacroAssembler::JumpIfInstanceTypeIsNotSequentialAscii(Register type,
+ Register scratch,
+ Label* failure) {
+ int kFlatAsciiStringMask =
+ kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask;
+ int kFlatAsciiStringTag = ASCII_STRING_TYPE;
+ and_(scratch, type, Operand(kFlatAsciiStringMask));
+ cmp(scratch, Operand(kFlatAsciiStringTag));
+ b(ne, failure);
+}
+
+
#ifdef ENABLE_DEBUGGER_SUPPORT
CodePatcher::CodePatcher(byte* address, int instructions)
: address_(address),
Register scratch2,
Label* not_flat_ascii_strings);
+ // Checks if both instance types are sequential ASCII strings and jumps to
+ // label if either is not.
+ void JumpIfBothInstanceTypesAreNotSequentialAscii(
+ Register first_object_instance_type,
+ Register second_object_instance_type,
+ Register scratch1,
+ Register scratch2,
+ Label* failure);
+
+ // Check if instance type is sequential ASCII string and jump to label if
+ // it is not.
+ void JumpIfInstanceTypeIsNotSequentialAscii(Register type,
+ Register scratch,
+ Label* failure);
+
+
private:
void Jump(intptr_t target, RelocInfo::Mode rmode, Condition cond = al);
void Call(intptr_t target, RelocInfo::Mode rmode, Condition cond = al);
Label make_two_character_string, make_flat_ascii_string;
GenerateTwoCharacterSymbolTableProbe(masm, ebx, ecx, eax, edx, edi,
&make_two_character_string);
+ __ IncrementCounter(&Counters::string_add_native, 1);
__ ret(2 * kPointerSize);
__ bind(&make_two_character_string);
// Calculate capacity mask from the symbol table capacity.
Register mask = scratch2;
- static const int kCapacityOffset =
- FixedArray::kHeaderSize +
- SymbolTable::kCapacityIndex * kPointerSize;
- __ mov(mask, FieldOperand(symbol_table, kCapacityOffset));
+ __ mov(mask, FieldOperand(symbol_table, SymbolTable::kCapacityOffset));
__ SmiUntag(mask);
__ sub(Operand(mask), Immediate(1));
// Load the entry from the symble table.
Register candidate = scratch; // Scratch register contains candidate.
- ASSERT_EQ(1, SymbolTableShape::kEntrySize);
- static const int kFirstElementOffset =
- FixedArray::kHeaderSize +
- SymbolTable::kPrefixStartIndex * kPointerSize +
- SymbolTableShape::kPrefixSize * kPointerSize;
+ ASSERT_EQ(1, SymbolTable::kEntrySize);
__ mov(candidate,
FieldOperand(symbol_table,
scratch,
times_pointer_size,
- kFirstElementOffset));
+ SymbolTable::kElementsStartOffset));
// If entry is undefined no string with this hash can be found.
__ cmp(candidate, Factory::undefined_value());
Label make_two_character_string;
GenerateTwoCharacterSymbolTableProbe(masm, ebx, ecx, eax, edx, edi,
&make_two_character_string);
- __ ret(2 * kPointerSize);
+ __ ret(3 * kPointerSize);
__ bind(&make_two_character_string);
// Setup registers for allocating the two character string.
static const int kEntrySize = Shape::kEntrySize;
static const int kElementsStartOffset =
kHeaderSize + kElementsStartIndex * kPointerSize;
+ static const int kCapacityOffset =
+ kHeaderSize + kCapacityIndex * kPointerSize;
// Constant used for denoting a absent entry.
static const int kNotFound = -1;
// rbx: length of first string
// rcx: length of second string
// rdx: second string
- // r8: instance type of first string if string check was performed above
- // r9: instance type of first string if string check was performed above
- Label string_add_flat_result;
+ // r8: map of first string if string check was performed above
+ // r9: map of second string if string check was performed above
+ Label string_add_flat_result, longer_than_two;
__ bind(&both_not_zero_length);
- // Look at the length of the result of adding the two strings.
- __ addl(rbx, rcx);
- // Use the runtime system when adding two one character strings, as it
- // contains optimizations for this specific case using the symbol table.
- __ cmpl(rbx, Immediate(2));
- __ j(equal, &string_add_runtime);
+
// If arguments where known to be strings, maps are not loaded to r8 and r9
// by the code above.
if (!string_check_) {
// Get the instance types of the two strings as they will be needed soon.
__ movzxbl(r8, FieldOperand(r8, Map::kInstanceTypeOffset));
__ movzxbl(r9, FieldOperand(r9, Map::kInstanceTypeOffset));
+
+ // Look at the length of the result of adding the two strings.
+ __ addl(rbx, rcx);
+ // Use the runtime system when adding two one character strings, as it
+ // contains optimizations for this specific case using the symbol table.
+ __ cmpl(rbx, Immediate(2));
+ __ j(not_equal, &longer_than_two);
+
+ // Check that both strings are non-external ascii strings.
+ __ JumpIfBothInstanceTypesAreNotSequentialAscii(r8, r9, rbx, rcx,
+ &string_add_runtime);
+
+ // Get the two characters forming the sub string.
+ __ movzxbq(rbx, FieldOperand(rax, SeqAsciiString::kHeaderSize));
+ __ movzxbq(rcx, FieldOperand(rdx, SeqAsciiString::kHeaderSize));
+
+ // Try to lookup two character string in symbol table. If it is not found
+ // just allocate a new one.
+ Label make_two_character_string, make_flat_ascii_string;
+ GenerateTwoCharacterSymbolTableProbe(masm, rbx, rcx, r14, r12, rdi, r15,
+ &make_two_character_string);
+ __ IncrementCounter(&Counters::string_add_native, 1);
+ __ ret(2 * kPointerSize);
+
+ __ bind(&make_two_character_string);
+ __ Set(rbx, 2);
+ __ jmp(&make_flat_ascii_string);
+
+ __ bind(&longer_than_two);
// Check if resulting string will be flat.
__ cmpl(rbx, Immediate(String::kMinNonFlatLength));
__ j(below, &string_add_flat_result);
__ j(zero, &non_ascii_string_add_flat_result);
__ testl(r9, Immediate(kAsciiStringTag));
__ j(zero, &string_add_runtime);
+
+ __ bind(&make_flat_ascii_string);
// Both strings are ascii strings. As they are short they are both flat.
__ AllocateAsciiString(rcx, rbx, rdi, r14, r15, &string_add_runtime);
// rcx: result string
__ bind(&done);
}
+void StringStubBase::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
+ Register c1,
+ Register c2,
+ Register scratch1,
+ Register scratch2,
+ Register scratch3,
+ Register scratch4,
+ Label* not_found) {
+ // Register scratch3 is the general scratch register in this function.
+ Register scratch = scratch3;
+
+ // Make sure that both characters are not digits as such strings has a
+ // different hash algorithm. Don't try to look for these in the symbol table.
+ Label not_array_index;
+ __ movq(scratch, c1);
+ __ subq(scratch, Immediate(static_cast<int>('0')));
+ __ cmpq(scratch, Immediate(static_cast<int>('9' - '0')));
+ __ j(above, ¬_array_index);
+ __ movq(scratch, c2);
+ __ subq(scratch, Immediate(static_cast<int>('0')));
+ __ cmpq(scratch, Immediate(static_cast<int>('9' - '0')));
+ __ j(below_equal, not_found);
+
+ __ bind(¬_array_index);
+ // Calculate the two character string hash.
+ Register hash = scratch1;
+ GenerateHashInit(masm, hash, c1, scratch);
+ GenerateHashAddCharacter(masm, hash, c2, scratch);
+ GenerateHashGetHash(masm, hash, scratch);
+
+ // Collect the two characters in a register.
+ Register chars = c1;
+ __ shl(c2, Immediate(kBitsPerByte));
+ __ orl(chars, c2);
+
+ // chars: two character string, char 1 in byte 0 and char 2 in byte 1.
+ // hash: hash of two character string.
+
+ // Load the symbol table.
+ Register symbol_table = c2;
+ __ LoadRoot(symbol_table, Heap::kSymbolTableRootIndex);
+
+ // Calculate capacity mask from the symbol table capacity.
+ Register mask = scratch2;
+ __ movq(mask, FieldOperand(symbol_table, SymbolTable::kCapacityOffset));
+ __ SmiToInteger32(mask, mask);
+ __ decl(mask);
+
+ Register undefined = scratch4;
+ __ LoadRoot(undefined, Heap::kUndefinedValueRootIndex);
+
+ // Registers
+ // chars: two character string, char 1 in byte 0 and char 2 in byte 1.
+ // hash: hash of two character string (32-bit int)
+ // symbol_table: symbol table
+ // mask: capacity mask (32-bit int)
+ // undefined: undefined value
+ // scratch: -
+
+ // Perform a number of probes in the symbol table.
+ static const int kProbes = 4;
+ Label found_in_symbol_table;
+ Label next_probe[kProbes];
+ for (int i = 0; i < kProbes; i++) {
+ // Calculate entry in symbol table.
+ __ movl(scratch, hash);
+ if (i > 0) {
+ __ addl(scratch, Immediate(SymbolTable::GetProbeOffset(i)));
+ }
+ __ andl(scratch, mask);
+
+ // Load the entry from the symble table.
+ Register candidate = scratch; // Scratch register contains candidate.
+ ASSERT_EQ(1, SymbolTable::kEntrySize);
+ __ movq(candidate,
+ FieldOperand(symbol_table,
+ scratch,
+ times_pointer_size,
+ SymbolTable::kElementsStartOffset));
+
+ // If entry is undefined no string with this hash can be found.
+ __ cmpq(candidate, undefined);
+ __ j(equal, not_found);
+
+ // If length is not 2 the string is not a candidate.
+ __ cmpl(FieldOperand(candidate, String::kLengthOffset), Immediate(2));
+ __ j(not_equal, &next_probe[i]);
+
+ // We use kScratchRegister as a temporary register in assumption that
+ // JumpIfInstanceTypeIsNotSequentialAscii does not use it implicitly
+ Register temp = kScratchRegister;
+
+ // Check that the candidate is a non-external ascii string.
+ __ movq(temp, FieldOperand(candidate, HeapObject::kMapOffset));
+ __ movzxbl(temp, FieldOperand(temp, Map::kInstanceTypeOffset));
+ __ JumpIfInstanceTypeIsNotSequentialAscii(
+ temp, temp, &next_probe[i]);
+
+ // Check if the two characters match.
+ __ movl(temp, FieldOperand(candidate, SeqAsciiString::kHeaderSize));
+ __ andl(temp, Immediate(0x0000ffff));
+ __ cmpl(chars, temp);
+ __ j(equal, &found_in_symbol_table);
+ __ bind(&next_probe[i]);
+ }
+
+ // No matching 2 character string found by probing.
+ __ jmp(not_found);
+
+ // Scratch register contains result when we fall through to here.
+ Register result = scratch;
+ __ bind(&found_in_symbol_table);
+ if (!result.is(rax)) {
+ __ movq(rax, result);
+ }
+}
+
+
+void StringStubBase::GenerateHashInit(MacroAssembler* masm,
+ Register hash,
+ Register character,
+ Register scratch) {
+ // hash = character + (character << 10);
+ __ movl(hash, character);
+ __ shll(hash, Immediate(10));
+ __ addl(hash, character);
+ // hash ^= hash >> 6;
+ __ movl(scratch, hash);
+ __ sarl(scratch, Immediate(6));
+ __ xorl(hash, scratch);
+}
+
+
+void StringStubBase::GenerateHashAddCharacter(MacroAssembler* masm,
+ Register hash,
+ Register character,
+ Register scratch) {
+ // hash += character;
+ __ addl(hash, character);
+ // hash += hash << 10;
+ __ movl(scratch, hash);
+ __ shll(scratch, Immediate(10));
+ __ addl(hash, scratch);
+ // hash ^= hash >> 6;
+ __ movl(scratch, hash);
+ __ sarl(scratch, Immediate(6));
+ __ xorl(hash, scratch);
+}
+
+
+void StringStubBase::GenerateHashGetHash(MacroAssembler* masm,
+ Register hash,
+ Register scratch) {
+ // hash += hash << 3;
+ __ movl(scratch, hash);
+ __ shll(scratch, Immediate(3));
+ __ addl(hash, scratch);
+ // hash ^= hash >> 11;
+ __ movl(scratch, hash);
+ __ sarl(scratch, Immediate(11));
+ __ xorl(hash, scratch);
+ // hash += hash << 15;
+ __ movl(scratch, hash);
+ __ shll(scratch, Immediate(15));
+ __ addl(hash, scratch);
+
+ // if (hash == 0) hash = 27;
+ Label hash_not_zero;
+ __ testl(hash, hash);
+ __ j(not_zero, &hash_not_zero);
+ __ movl(hash, Immediate(27));
+ __ bind(&hash_not_zero);
+}
void SubStringStub::Generate(MacroAssembler* masm) {
Label runtime;
// rax: string
// rbx: instance type
// Calculate length of sub string using the smi values.
+ Label result_longer_than_two;
__ movq(rcx, Operand(rsp, kToOffset));
__ movq(rdx, Operand(rsp, kFromOffset));
__ JumpIfNotBothPositiveSmi(rcx, rdx, &runtime);
__ SmiSub(rcx, rcx, rdx, NULL); // Overflow doesn't happen.
__ j(negative, &runtime);
- // Handle sub-strings of length 2 and less in the runtime system.
+ // Special handling of sub-strings of length 1 and 2. One character strings
+ // are handled in the runtime system (looked up in the single character
+ // cache). Two character strings are looked for in the symbol cache.
__ SmiToInteger32(rcx, rcx);
__ cmpl(rcx, Immediate(2));
- __ j(below_equal, &runtime);
+ __ j(greater, &result_longer_than_two);
+ __ j(less, &runtime);
+
+ // Sub string of length 2 requested.
+ // rax: string
+ // rbx: instance type
+ // rcx: sub string length (value is 2)
+ // rdx: from index (smi)
+ __ JumpIfInstanceTypeIsNotSequentialAscii(rbx, rbx, &runtime);
+
+ // Get the two characters forming the sub string.
+ __ SmiToInteger32(rdx, rdx); // From index is no longer smi.
+ __ movzxbq(rbx, FieldOperand(rax, rdx, times_1, SeqAsciiString::kHeaderSize));
+ __ movzxbq(rcx,
+ FieldOperand(rax, rdx, times_1, SeqAsciiString::kHeaderSize + 1));
+
+ // Try to lookup two character string in symbol table.
+ Label make_two_character_string;
+ GenerateTwoCharacterSymbolTableProbe(masm, rbx, rcx, rax, rdx, rdi, r14,
+ &make_two_character_string);
+ __ ret(3 * kPointerSize);
+
+ __ bind(&make_two_character_string);
+ // Setup registers for allocating the two character string.
+ __ movq(rax, Operand(rsp, kStringOffset));
+ __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
+ __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
+ __ Set(rcx, 2);
+
+ __ bind(&result_longer_than_two);
// rax: string
// rbx: instance type
// rcx: result string length
// Check for flat ascii string
Label non_ascii_flat;
- __ and_(rbx, Immediate(kStringRepresentationMask | kStringEncodingMask));
- __ cmpb(rbx, Immediate(kSeqStringTag | kAsciiStringTag));
- __ j(not_equal, &non_ascii_flat);
+ __ JumpIfInstanceTypeIsNotSequentialAscii(rbx, rbx, &non_ascii_flat);
// Allocate the result.
__ AllocateAsciiString(rax, rcx, rbx, rdx, rdi, &runtime);
Register src, // Must be rsi.
Register count, // Must be rcx.
bool ascii);
+
+
+ // Probe the symbol table for a two character string. If the string is
+ // not found by probing a jump to the label not_found is performed. This jump
+ // does not guarantee that the string is not in the symbol table. If the
+ // string is found the code falls through with the string in register rax.
+ void GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
+ Register c1,
+ Register c2,
+ Register scratch1,
+ Register scratch2,
+ Register scratch3,
+ Register scratch4,
+ Label* not_found);
+
+ // Generate string hash.
+ void GenerateHashInit(MacroAssembler* masm,
+ Register hash,
+ Register character,
+ Register scratch);
+ void GenerateHashAddCharacter(MacroAssembler* masm,
+ Register hash,
+ Register character,
+ Register scratch);
+ void GenerateHashGetHash(MacroAssembler* masm,
+ Register hash,
+ Register scratch);
};
}
+void MacroAssembler::JumpIfInstanceTypeIsNotSequentialAscii(
+ Register instance_type,
+ Register scratch,
+ Label *failure) {
+ if (!scratch.is(instance_type)) {
+ movl(scratch, instance_type);
+ }
+
+ const int kFlatAsciiStringMask =
+ kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask;
+
+ andl(scratch, Immediate(kFlatAsciiStringMask));
+ cmpl(scratch, Immediate(kStringTag | kSeqStringTag | kAsciiStringTag));
+ j(not_equal, failure);
+}
+
+
+void MacroAssembler::JumpIfBothInstanceTypesAreNotSequentialAscii(
+ Register first_object_instance_type,
+ Register second_object_instance_type,
+ Register scratch1,
+ Register scratch2,
+ Label* on_fail) {
+ // Load instance type for both strings.
+ movq(scratch1, first_object_instance_type);
+ movq(scratch2, second_object_instance_type);
+
+ // Check that both are flat ascii strings.
+ ASSERT(kNotStringTag != 0);
+ const int kFlatAsciiStringMask =
+ kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask;
+ const int kFlatAsciiStringTag = ASCII_STRING_TYPE;
+
+ andl(scratch1, Immediate(kFlatAsciiStringMask));
+ andl(scratch2, Immediate(kFlatAsciiStringMask));
+ // Interleave the bits to check both scratch1 and scratch2 in one test.
+ ASSERT_EQ(0, kFlatAsciiStringMask & (kFlatAsciiStringMask << 3));
+ lea(scratch1, Operand(scratch1, scratch2, times_8, 0));
+ cmpl(scratch1,
+ Immediate(kFlatAsciiStringTag + (kFlatAsciiStringTag << 3)));
+ j(not_equal, on_fail);
+}
+
+
void MacroAssembler::Move(Register dst, Handle<Object> source) {
ASSERT(!source->IsFailure());
if (source->IsSmi()) {
Register scratch2,
Label* on_not_both_flat_ascii);
+ // Check whether the instance type represents a flat ascii string. Jump to the
+ // label if not. If the instance type can be scratched specify same register
+ // for both instance type and scratch.
+ void JumpIfInstanceTypeIsNotSequentialAscii(Register instance_type,
+ Register scratch,
+ Label *on_not_flat_ascii_string);
+
+ void JumpIfBothInstanceTypesAreNotSequentialAscii(
+ Register first_object_instance_type,
+ Register second_object_instance_type,
+ Register scratch1,
+ Register scratch2,
+ Label* on_fail);
+
// ---------------------------------------------------------------------------
// Macro instructions.
projects / platform / upstream / v8.git / commitdiff