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Port of changes from r3842 (symbol table probing for two character strings) to x64 and arm

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Review URL: http://codereview.chromium.org/661469

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4050 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
vegorov@chromium.org 2010-03-08 11:58:33 +00:00
parent 95964bd95f
commit 6b47d26217
10 changed files with 659 additions and 38 deletions
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246
src/arm/codegen-arm.cc
View File

@ -7249,6 +7249,170 @@ void StringStubBase::GenerateCopyCharactersLong(MacroAssembler* masm,
}
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, &not_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(&not_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;
@ -7284,11 +7448,14 @@ void SubStringStub::Generate(MacroAssembler* masm) {
__ 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)
@ -7302,6 +7469,7 @@ void SubStringStub::Generate(MacroAssembler* masm) {
// r1: instance type
// r2: length
// r3: from index (untaged smi)
// r5: string
// r6: from (smi)
// r7: to (smi)
@ -7328,6 +7496,7 @@ void SubStringStub::Generate(MacroAssembler* masm) {
// r1: instance type.
// r2: length
// r3: from index (untaged smi)
// r5: string
// r6: from (smi)
// r7: to (smi)
@ -7337,6 +7506,7 @@ void SubStringStub::Generate(MacroAssembler* masm) {
// r1: instance type.
// r2: result string length.
// r3: from index (untaged smi)
// r5: string.
// r6: from offset (smi)
// Check for flat ascii string.
@ -7345,6 +7515,35 @@ void SubStringStub::Generate(MacroAssembler* masm) {
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);
@ -7553,14 +7752,52 @@ void StringAddStub::Generate(MacroAssembler* masm) {
// 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);
@ -7639,6 +7876,7 @@ void StringAddStub::Generate(MacroAssembler* masm) {
// 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));

30
src/arm/codegen-arm.h
View File

@ -564,6 +564,36 @@ class StringStubBase: public CodeStub {
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);
};

45
src/arm/macro-assembler-arm.cc
View File

@ -1417,15 +1417,12 @@ void MacroAssembler::JumpIfNonSmisNotBothSequentialAsciiStrings(
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,
@ -1446,6 +1443,36 @@ 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),

16
src/arm/macro-assembler-arm.h
View File

@ -425,6 +425,22 @@ class MacroAssembler: public Assembler {
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);

16
src/ia32/codegen-ia32.cc
View File

@ -11019,6 +11019,7 @@ void StringAddStub::Generate(MacroAssembler* masm) {
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);
@ -11299,10 +11300,7 @@ void StringStubBase::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
// 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));
@ -11327,16 +11325,12 @@ void StringStubBase::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
// 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());
@ -11490,7 +11484,7 @@ void SubStringStub::Generate(MacroAssembler* masm) {
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.

2
src/objects.h
View File

@ -1969,6 +1969,8 @@ class HashTable: public FixedArray {
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;

257
src/x64/codegen-x64.cc
View File

@ -9000,16 +9000,11 @@ void StringAddStub::Generate(MacroAssembler* masm) {
// 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_) {
@ -9019,6 +9014,35 @@ void StringAddStub::Generate(MacroAssembler* masm) {
// 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);
@ -9085,6 +9109,8 @@ void StringAddStub::Generate(MacroAssembler* masm) {
__ 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
@ -9235,6 +9261,179 @@ void StringStubBase::GenerateCopyCharactersREP(MacroAssembler* masm,
__ 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, &not_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(&not_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;
@ -9261,25 +9460,55 @@ void SubStringStub::Generate(MacroAssembler* masm) {
// 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);

27
src/x64/codegen-x64.h
View File

@ -773,6 +773,33 @@ class StringStubBase: public CodeStub {
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);
};

44
src/x64/macro-assembler-x64.cc
View File

@ -1400,6 +1400,50 @@ void MacroAssembler::JumpIfNotBothSequentialAsciiStrings(Register first_object,
}
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()) {

14
src/x64/macro-assembler-x64.h
View File

@ -426,6 +426,20 @@ class MacroAssembler: public Assembler {
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.