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Speed up FastAsciiArrayJoin on ia32 by improving hand-written assembly code.

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Review URL: http://codereview.chromium.org/6148007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6310 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
whesse@chromium.org 2011-01-14 10:57:49 +00:00
parent 3800b24f69
commit 962d7019aa
4 changed files with 480 additions and 318 deletions
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341
src/ia32/codegen-ia32.cc
View File

@ -6649,38 +6649,41 @@ void CodeGenerator::GenerateIsArray(ZoneList<Expression*>* args) {
void CodeGenerator::GenerateFastAsciiArrayJoin(ZoneList<Expression*>* args) {
Label bailout, done, one_char_separator, long_separator,
non_trivial_array, not_size_one_array, loop, loop_condition,
loop_1, loop_1_condition, loop_2, loop_2_entry, loop_3, loop_3_entry;
ASSERT(args->length() == 2);
// We will leave the separator on the stack until the end of the function.
Load(args->at(1));
// Load this to eax (= array)
Load(args->at(0));
Result array_result = frame_->Pop();
array_result.ToRegister(eax);
frame_->SpillAll();
Label bailout;
Label done;
// All aliases of the same register have disjoint lifetimes.
Register array = eax;
Register result_pos = no_reg;
Register elements = no_reg; // Will be eax.
Register index = edi;
Register index = edx;
Register current_string_length = ecx; // Will be ecx when live.
Register string_length = ecx;
Register current_string = edx;
Register string = esi;
Register scratch = ebx;
Register scratch_2 = esi;
Register new_padding_chars = scratch_2;
Register array_length = edi;
Register result_pos = no_reg; // Will be edi.
Operand separator = Operand(esp, 4 * kPointerSize); // Already pushed.
Operand elements = Operand(esp, 3 * kPointerSize);
Operand result = Operand(esp, 2 * kPointerSize);
Operand padding_chars = Operand(esp, 1 * kPointerSize);
Operand array_length = Operand(esp, 0);
__ sub(Operand(esp), Immediate(4 * kPointerSize));
// Check that eax is a JSArray
// Separator operand is already pushed.
Operand separator_operand = Operand(esp, 2 * kPointerSize);
Operand result_operand = Operand(esp, 1 * kPointerSize);
Operand array_length_operand = Operand(esp, 0);
__ sub(Operand(esp), Immediate(2 * kPointerSize));
__ cld();
// Check that the array is a JSArray
__ test(array, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ CmpObjectType(array, JS_ARRAY_TYPE, scratch);
@ -6691,140 +6694,226 @@ void CodeGenerator::GenerateFastAsciiArrayJoin(ZoneList<Expression*>* args) {
1 << Map::kHasFastElements);
__ j(zero, &bailout);
// If the array is empty, return the empty string.
__ mov(scratch, FieldOperand(array, JSArray::kLengthOffset));
__ sar(scratch, 1);
Label non_trivial;
__ j(not_zero, &non_trivial);
__ mov(result, Factory::empty_string());
// If the array has length zero, return the empty string.
__ mov(array_length, FieldOperand(array, JSArray::kLengthOffset));
__ sar(array_length, 1);
__ j(not_zero, &non_trivial_array);
__ mov(result_operand, Factory::empty_string());
__ jmp(&done);
__ bind(&non_trivial);
__ mov(array_length, scratch);
__ mov(scratch, FieldOperand(array, JSArray::kElementsOffset));
__ mov(elements, scratch);
// Save the array length.
__ bind(&non_trivial_array);
__ mov(array_length_operand, array_length);
// Save the FixedArray containing array's elements.
// End of array's live range.
result_pos = array;
elements = array;
__ mov(elements, FieldOperand(array, JSArray::kElementsOffset));
array = no_reg;
// Check that the separator is a flat ascii string.
__ mov(current_string, separator);
__ test(current_string, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ mov(scratch, FieldOperand(current_string, HeapObject::kMapOffset));
__ mov_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ and_(scratch, Immediate(
kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
__ cmp(scratch, kStringTag | kAsciiStringTag | kSeqStringTag);
__ j(not_equal, &bailout);
// If the separator is the empty string, replace it with NULL.
// The test for NULL is quicker than the empty string test, in a loop.
__ cmp(FieldOperand(current_string, SeqAsciiString::kLengthOffset),
Immediate(0));
Label separator_checked;
__ j(not_zero, &separator_checked);
__ mov(separator, Immediate(0));
__ bind(&separator_checked);
// Check that elements[0] is a flat ascii string, and copy it in new space.
__ mov(scratch, elements);
__ mov(current_string, FieldOperand(scratch, FixedArray::kHeaderSize));
__ test(current_string, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ mov(scratch, FieldOperand(current_string, HeapObject::kMapOffset));
__ mov_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ and_(scratch, Immediate(
kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
__ cmp(scratch, kStringTag | kAsciiStringTag | kSeqStringTag);
__ j(not_equal, &bailout);
// Allocate space to copy it. Round up the size to the alignment granularity.
__ mov(current_string_length,
FieldOperand(current_string, String::kLengthOffset));
__ shr(current_string_length, 1);
// Live registers and stack values:
// current_string_length: length of elements[0].
// New string result in new space = elements[0]
__ AllocateAsciiString(result_pos, current_string_length, scratch_2,
index, no_reg, &bailout);
__ mov(result, result_pos);
// Adjust current_string_length to include padding bytes at end of string.
// Keep track of the number of padding bytes.
__ mov(new_padding_chars, current_string_length);
__ add(Operand(current_string_length), Immediate(kObjectAlignmentMask));
__ and_(Operand(current_string_length), Immediate(~kObjectAlignmentMask));
__ sub(new_padding_chars, Operand(current_string_length));
__ neg(new_padding_chars);
__ mov(padding_chars, new_padding_chars);
Label copy_loop_1_done;
Label copy_loop_1;
__ test(current_string_length, Operand(current_string_length));
__ j(zero, &copy_loop_1_done);
__ bind(&copy_loop_1);
__ sub(Operand(current_string_length), Immediate(kPointerSize));
__ mov(scratch, FieldOperand(current_string, current_string_length,
times_1, SeqAsciiString::kHeaderSize));
__ mov(FieldOperand(result_pos, current_string_length,
times_1, SeqAsciiString::kHeaderSize),
scratch);
__ j(not_zero, &copy_loop_1);
__ bind(&copy_loop_1_done);
__ mov(index, Immediate(1));
// Check that all array elements are sequential ASCII strings, and
// accumulate the sum of their lengths, as a smi-encoded value.
__ Set(index, Immediate(0));
__ Set(string_length, Immediate(0));
// Loop condition: while (index < length).
Label loop;
// Live loop registers: index, array_length, string,
// scratch, string_length, elements.
__ jmp(&loop_condition);
__ bind(&loop);
__ cmp(index, array_length);
__ cmp(index, Operand(array_length));
__ j(greater_equal, &done);
// If the separator is the empty string, signalled by NULL, skip it.
Label separator_done;
__ mov(current_string, separator);
__ test(current_string, Operand(current_string));
__ j(zero, &separator_done);
// Append separator to result. It is known to be a flat ascii string.
__ AppendStringToTopOfNewSpace(current_string, current_string_length,
result_pos, scratch, scratch_2, result,
padding_chars, &bailout);
__ bind(&separator_done);
// Add next element of array to the end of the result.
// Get current_string = array[index].
__ mov(scratch, elements);
__ mov(current_string, FieldOperand(scratch, index,
__ mov(string, FieldOperand(elements, index,
times_pointer_size,
FixedArray::kHeaderSize));
// If current != flat ascii string drop result, return undefined.
__ test(current_string, Immediate(kSmiTagMask));
__ test(string, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ mov(scratch, FieldOperand(current_string, HeapObject::kMapOffset));
__ mov_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ mov(scratch, FieldOperand(string, HeapObject::kMapOffset));
__ movzx_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ and_(scratch, Immediate(
kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
__ cmp(scratch, kStringTag | kAsciiStringTag | kSeqStringTag);
__ j(not_equal, &bailout);
__ add(string_length,
FieldOperand(string, SeqAsciiString::kLengthOffset));
__ j(overflow, &bailout);
__ add(Operand(index), Immediate(1));
__ bind(&loop_condition);
__ cmp(index, Operand(array_length));
__ j(less, &loop);
// If array_length is 1, return elements[0], a string.
__ cmp(array_length, 1);
__ j(not_equal, &not_size_one_array);
__ mov(scratch, FieldOperand(elements, FixedArray::kHeaderSize));
__ mov(result_operand, scratch);
__ jmp(&done);
__ bind(&not_size_one_array);
// End of array_length live range.
result_pos = array_length;
array_length = no_reg;
// Live registers:
// string_length: Sum of string lengths, as a smi.
// elements: FixedArray of strings.
// Check that the separator is a flat ASCII string.
__ mov(string, separator_operand);
__ test(string, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ mov(scratch, FieldOperand(string, HeapObject::kMapOffset));
__ movzx_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ and_(scratch, Immediate(
kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
__ cmp(scratch, kStringTag | kAsciiStringTag | kSeqStringTag);
__ j(not_equal, &bailout);
// Append current to the result.
__ AppendStringToTopOfNewSpace(current_string, current_string_length,
result_pos, scratch, scratch_2, result,
padding_chars, &bailout);
// Add (separator length times array_length) - separator length
// to string_length.
__ mov(scratch, separator_operand);
__ mov(scratch, FieldOperand(scratch, SeqAsciiString::kLengthOffset));
__ sub(string_length, Operand(scratch)); // May be negative, temporarily.
__ imul(scratch, array_length_operand);
__ j(overflow, &bailout);
__ add(string_length, Operand(scratch));
__ j(overflow, &bailout);
__ shr(string_length, 1);
// Live registers and stack values:
// string_length
// elements
__ AllocateAsciiString(result_pos, string_length, scratch,
index, string, &bailout);
__ mov(result_operand, result_pos);
__ lea(result_pos, FieldOperand(result_pos, SeqAsciiString::kHeaderSize));
__ mov(string, separator_operand);
__ cmp(FieldOperand(string, SeqAsciiString::kLengthOffset),
Immediate(Smi::FromInt(1)));
__ j(equal, &one_char_separator);
__ j(greater, &long_separator);
// Empty separator case
__ mov(index, Immediate(0));
__ jmp(&loop_1_condition);
// Loop condition: while (index < length).
__ bind(&loop_1);
// Each iteration of the loop concatenates one string to the result.
// Live values in registers:
// index: which element of the elements array we are adding to the result.
// result_pos: the position to which we are currently copying characters.
// elements: the FixedArray of strings we are joining.
// Get string = array[index].
__ mov(string, FieldOperand(elements, index,
times_pointer_size,
FixedArray::kHeaderSize));
__ mov(string_length,
FieldOperand(string, String::kLengthOffset));
__ shr(string_length, 1);
__ lea(string,
FieldOperand(string, SeqAsciiString::kHeaderSize));
__ CopyBytes(string, result_pos, string_length, scratch);
__ add(Operand(index), Immediate(1));
__ jmp(&loop); // End while (index < length).
__ bind(&loop_1_condition);
__ cmp(index, array_length_operand);
__ j(less, &loop_1); // End while (index < length).
__ jmp(&done);
// One-character separator case
__ bind(&one_char_separator);
// Replace separator with its ascii character value.
__ mov_b(scratch, FieldOperand(string, SeqAsciiString::kHeaderSize));
__ mov_b(separator_operand, scratch);
__ Set(index, Immediate(0));
// Jump into the loop after the code that copies the separator, so the first
// element is not preceded by a separator
__ jmp(&loop_2_entry);
// Loop condition: while (index < length).
__ bind(&loop_2);
// Each iteration of the loop concatenates one string to the result.
// Live values in registers:
// index: which element of the elements array we are adding to the result.
// result_pos: the position to which we are currently copying characters.
// Copy the separator character to the result.
__ mov_b(scratch, separator_operand);
__ mov_b(Operand(result_pos, 0), scratch);
__ inc(result_pos);
__ bind(&loop_2_entry);
// Get string = array[index].
__ mov(string, FieldOperand(elements, index,
times_pointer_size,
FixedArray::kHeaderSize));
__ mov(string_length,
FieldOperand(string, String::kLengthOffset));
__ shr(string_length, 1);
__ lea(string,
FieldOperand(string, SeqAsciiString::kHeaderSize));
__ CopyBytes(string, result_pos, string_length, scratch);
__ add(Operand(index), Immediate(1));
__ cmp(index, array_length_operand);
__ j(less, &loop_2); // End while (index < length).
__ jmp(&done);
// Long separator case (separator is more than one character).
__ bind(&long_separator);
__ Set(index, Immediate(0));
// Jump into the loop after the code that copies the separator, so the first
// element is not preceded by a separator
__ jmp(&loop_3_entry);
// Loop condition: while (index < length).
__ bind(&loop_3);
// Each iteration of the loop concatenates one string to the result.
// Live values in registers:
// index: which element of the elements array we are adding to the result.
// result_pos: the position to which we are currently copying characters.
// Copy the separator to the result.
__ mov(string, separator_operand);
__ mov(string_length,
FieldOperand(string, String::kLengthOffset));
__ shr(string_length, 1);
__ lea(string,
FieldOperand(string, SeqAsciiString::kHeaderSize));
__ CopyBytes(string, result_pos, string_length, scratch);
__ bind(&loop_3_entry);
// Get string = array[index].
__ mov(string, FieldOperand(elements, index,
times_pointer_size,
FixedArray::kHeaderSize));
__ mov(string_length,
FieldOperand(string, String::kLengthOffset));
__ shr(string_length, 1);
__ lea(string,
FieldOperand(string, SeqAsciiString::kHeaderSize));
__ CopyBytes(string, result_pos, string_length, scratch);
__ add(Operand(index), Immediate(1));
__ cmp(index, array_length_operand);
__ j(less, &loop_3); // End while (index < length).
__ jmp(&done);
__ bind(&bailout);
__ mov(result, Factory::undefined_value());
__ mov(result_operand, Factory::undefined_value());
__ bind(&done);
__ mov(eax, result);
__ mov(eax, result_operand);
// Drop temp values from the stack, and restore context register.
__ add(Operand(esp), Immediate(4 * kPointerSize));
__ add(Operand(esp), Immediate(2 * kPointerSize));
__ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
frame_->Drop(1);

340
src/ia32/full-codegen-ia32.cc
View File

@ -3351,39 +3351,37 @@ void FullCodeGenerator::EmitGetCachedArrayIndex(ZoneList<Expression*>* args) {
void FullCodeGenerator::EmitFastAsciiArrayJoin(ZoneList<Expression*>* args) {
Label bailout;
Label done;
Label bailout, done, one_char_separator, long_separator,
non_trivial_array, not_size_one_array, loop, loop_condition,
loop_1, loop_1_condition, loop_2, loop_2_entry, loop_3, loop_3_entry;
ASSERT(args->length() == 2);
// We will leave the separator on the stack until the end of the function.
VisitForStackValue(args->at(1));
// Load this to eax (= array)
VisitForAccumulatorValue(args->at(0));
// All aliases of the same register have disjoint lifetimes.
Register array = eax;
Register result_pos = no_reg;
Register elements = no_reg; // Will be eax.
Register index = edi;
Register index = edx;
Register current_string_length = ecx; // Will be ecx when live.
Register string_length = ecx;
Register current_string = edx;
Register string = esi;
Register scratch = ebx;
Register scratch_2 = esi;
Register new_padding_chars = scratch_2;
Register array_length = edi;
Register result_pos = no_reg; // Will be edi.
Operand separator = Operand(esp, 4 * kPointerSize); // Already pushed.
Operand elements = Operand(esp, 3 * kPointerSize);
Operand result = Operand(esp, 2 * kPointerSize);
Operand padding_chars = Operand(esp, 1 * kPointerSize);
Operand array_length = Operand(esp, 0);
__ sub(Operand(esp), Immediate(4 * kPointerSize));
// Check that eax is a JSArray
// Separator operand is already pushed.
Operand separator_operand = Operand(esp, 2 * kPointerSize);
Operand result_operand = Operand(esp, 1 * kPointerSize);
Operand array_length_operand = Operand(esp, 0);
__ sub(Operand(esp), Immediate(2 * kPointerSize));
__ cld();
// Check that the array is a JSArray
__ test(array, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ CmpObjectType(array, JS_ARRAY_TYPE, scratch);
@ -3394,140 +3392,226 @@ void FullCodeGenerator::EmitFastAsciiArrayJoin(ZoneList<Expression*>* args) {
1 << Map::kHasFastElements);
__ j(zero, &bailout);
// If the array is empty, return the empty string.
__ mov(scratch, FieldOperand(array, JSArray::kLengthOffset));
__ sar(scratch, 1);
Label non_trivial;
__ j(not_zero, &non_trivial);
__ mov(result, Factory::empty_string());
// If the array has length zero, return the empty string.
__ mov(array_length, FieldOperand(array, JSArray::kLengthOffset));
__ sar(array_length, 1);
__ j(not_zero, &non_trivial_array);
__ mov(result_operand, Factory::empty_string());
__ jmp(&done);
__ bind(&non_trivial);
__ mov(array_length, scratch);
__ mov(scratch, FieldOperand(array, JSArray::kElementsOffset));
__ mov(elements, scratch);
// Save the array length.
__ bind(&non_trivial_array);
__ mov(array_length_operand, array_length);
// Save the FixedArray containing array's elements.
// End of array's live range.
result_pos = array;
elements = array;
__ mov(elements, FieldOperand(array, JSArray::kElementsOffset));
array = no_reg;
// Check that the separator is a flat ascii string.
__ mov(current_string, separator);
__ test(current_string, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ mov(scratch, FieldOperand(current_string, HeapObject::kMapOffset));
__ mov_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ and_(scratch, Immediate(
kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
__ cmp(scratch, kStringTag | kAsciiStringTag | kSeqStringTag);
__ j(not_equal, &bailout);
// If the separator is the empty string, replace it with NULL.
// The test for NULL is quicker than the empty string test, in a loop.
__ cmp(FieldOperand(current_string, SeqAsciiString::kLengthOffset),
Immediate(0));
Label separator_checked;
__ j(not_zero, &separator_checked);
__ mov(separator, Immediate(0));
__ bind(&separator_checked);
// Check that elements[0] is a flat ascii string, and copy it in new space.
__ mov(scratch, elements);
__ mov(current_string, FieldOperand(scratch, FixedArray::kHeaderSize));
__ test(current_string, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ mov(scratch, FieldOperand(current_string, HeapObject::kMapOffset));
__ mov_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ and_(scratch, Immediate(
kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
__ cmp(scratch, kStringTag | kAsciiStringTag | kSeqStringTag);
__ j(not_equal, &bailout);
// Allocate space to copy it. Round up the size to the alignment granularity.
__ mov(current_string_length,
FieldOperand(current_string, String::kLengthOffset));
__ shr(current_string_length, 1);
// Live registers and stack values:
// current_string_length: length of elements[0].
// New string result in new space = elements[0]
__ AllocateAsciiString(result_pos, current_string_length, scratch_2,
index, no_reg, &bailout);
__ mov(result, result_pos);
// Adjust current_string_length to include padding bytes at end of string.
// Keep track of the number of padding bytes.
__ mov(new_padding_chars, current_string_length);
__ add(Operand(current_string_length), Immediate(kObjectAlignmentMask));
__ and_(Operand(current_string_length), Immediate(~kObjectAlignmentMask));
__ sub(new_padding_chars, Operand(current_string_length));
__ neg(new_padding_chars);
__ mov(padding_chars, new_padding_chars);
Label copy_loop_1_done;
Label copy_loop_1;
__ test(current_string_length, Operand(current_string_length));
__ j(zero, &copy_loop_1_done);
__ bind(&copy_loop_1);
__ sub(Operand(current_string_length), Immediate(kPointerSize));
__ mov(scratch, FieldOperand(current_string, current_string_length,
times_1, SeqAsciiString::kHeaderSize));
__ mov(FieldOperand(result_pos, current_string_length,
times_1, SeqAsciiString::kHeaderSize),
scratch);
__ j(not_zero, &copy_loop_1);
__ bind(&copy_loop_1_done);
__ mov(index, Immediate(1));
// Check that all array elements are sequential ASCII strings, and
// accumulate the sum of their lengths, as a smi-encoded value.
__ Set(index, Immediate(0));
__ Set(string_length, Immediate(0));
// Loop condition: while (index < length).
Label loop;
// Live loop registers: index, array_length, string,
// scratch, string_length, elements.
__ jmp(&loop_condition);
__ bind(&loop);
__ cmp(index, array_length);
__ cmp(index, Operand(array_length));
__ j(greater_equal, &done);
// If the separator is the empty string, signalled by NULL, skip it.
Label separator_done;
__ mov(current_string, separator);
__ test(current_string, Operand(current_string));
__ j(zero, &separator_done);
// Append separator to result. It is known to be a flat ascii string.
__ AppendStringToTopOfNewSpace(current_string, current_string_length,
result_pos, scratch, scratch_2, result,
padding_chars, &bailout);
__ bind(&separator_done);
// Add next element of array to the end of the result.
// Get current_string = array[index].
__ mov(scratch, elements);
__ mov(current_string, FieldOperand(scratch, index,
__ mov(string, FieldOperand(elements, index,
times_pointer_size,
FixedArray::kHeaderSize));
// If current != flat ascii string drop result, return undefined.
__ test(current_string, Immediate(kSmiTagMask));
__ test(string, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ mov(scratch, FieldOperand(current_string, HeapObject::kMapOffset));
__ mov_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ mov(scratch, FieldOperand(string, HeapObject::kMapOffset));
__ movzx_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ and_(scratch, Immediate(
kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
__ cmp(scratch, kStringTag | kAsciiStringTag | kSeqStringTag);
__ j(not_equal, &bailout);
__ add(string_length,
FieldOperand(string, SeqAsciiString::kLengthOffset));
__ j(overflow, &bailout);
__ add(Operand(index), Immediate(1));
__ bind(&loop_condition);
__ cmp(index, Operand(array_length));
__ j(less, &loop);
// If array_length is 1, return elements[0], a string.
__ cmp(array_length, 1);
__ j(not_equal, &not_size_one_array);
__ mov(scratch, FieldOperand(elements, FixedArray::kHeaderSize));
__ mov(result_operand, scratch);
__ jmp(&done);
__ bind(&not_size_one_array);
// End of array_length live range.
result_pos = array_length;
array_length = no_reg;
// Live registers:
// string_length: Sum of string lengths, as a smi.
// elements: FixedArray of strings.
// Check that the separator is a flat ASCII string.
__ mov(string, separator_operand);
__ test(string, Immediate(kSmiTagMask));
__ j(zero, &bailout);
__ mov(scratch, FieldOperand(string, HeapObject::kMapOffset));
__ movzx_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
__ and_(scratch, Immediate(
kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
__ cmp(scratch, kStringTag | kAsciiStringTag | kSeqStringTag);
__ j(not_equal, &bailout);
// Append current to the result.
__ AppendStringToTopOfNewSpace(current_string, current_string_length,
result_pos, scratch, scratch_2, result,
padding_chars, &bailout);
// Add (separator length times array_length) - separator length
// to string_length.
__ mov(scratch, separator_operand);
__ mov(scratch, FieldOperand(scratch, SeqAsciiString::kLengthOffset));
__ sub(string_length, Operand(scratch)); // May be negative, temporarily.
__ imul(scratch, array_length_operand);
__ j(overflow, &bailout);
__ add(string_length, Operand(scratch));
__ j(overflow, &bailout);
__ shr(string_length, 1);
// Live registers and stack values:
// string_length
// elements
__ AllocateAsciiString(result_pos, string_length, scratch,
index, string, &bailout);
__ mov(result_operand, result_pos);
__ lea(result_pos, FieldOperand(result_pos, SeqAsciiString::kHeaderSize));
__ mov(string, separator_operand);
__ cmp(FieldOperand(string, SeqAsciiString::kLengthOffset),
Immediate(Smi::FromInt(1)));
__ j(equal, &one_char_separator);
__ j(greater, &long_separator);
// Empty separator case
__ mov(index, Immediate(0));
__ jmp(&loop_1_condition);
// Loop condition: while (index < length).
__ bind(&loop_1);
// Each iteration of the loop concatenates one string to the result.
// Live values in registers:
// index: which element of the elements array we are adding to the result.
// result_pos: the position to which we are currently copying characters.
// elements: the FixedArray of strings we are joining.
// Get string = array[index].
__ mov(string, FieldOperand(elements, index,
times_pointer_size,
FixedArray::kHeaderSize));
__ mov(string_length,
FieldOperand(string, String::kLengthOffset));
__ shr(string_length, 1);
__ lea(string,
FieldOperand(string, SeqAsciiString::kHeaderSize));
__ CopyBytes(string, result_pos, string_length, scratch);
__ add(Operand(index), Immediate(1));
__ jmp(&loop); // End while (index < length).
__ bind(&loop_1_condition);
__ cmp(index, array_length_operand);
__ j(less, &loop_1); // End while (index < length).
__ jmp(&done);
// One-character separator case
__ bind(&one_char_separator);
// Replace separator with its ascii character value.
__ mov_b(scratch, FieldOperand(string, SeqAsciiString::kHeaderSize));
__ mov_b(separator_operand, scratch);
__ Set(index, Immediate(0));
// Jump into the loop after the code that copies the separator, so the first
// element is not preceded by a separator
__ jmp(&loop_2_entry);
// Loop condition: while (index < length).
__ bind(&loop_2);
// Each iteration of the loop concatenates one string to the result.
// Live values in registers:
// index: which element of the elements array we are adding to the result.
// result_pos: the position to which we are currently copying characters.
// Copy the separator character to the result.
__ mov_b(scratch, separator_operand);
__ mov_b(Operand(result_pos, 0), scratch);
__ inc(result_pos);
__ bind(&loop_2_entry);
// Get string = array[index].
__ mov(string, FieldOperand(elements, index,
times_pointer_size,
FixedArray::kHeaderSize));
__ mov(string_length,
FieldOperand(string, String::kLengthOffset));
__ shr(string_length, 1);
__ lea(string,
FieldOperand(string, SeqAsciiString::kHeaderSize));
__ CopyBytes(string, result_pos, string_length, scratch);
__ add(Operand(index), Immediate(1));
__ cmp(index, array_length_operand);
__ j(less, &loop_2); // End while (index < length).
__ jmp(&done);
// Long separator case (separator is more than one character).
__ bind(&long_separator);
__ Set(index, Immediate(0));
// Jump into the loop after the code that copies the separator, so the first
// element is not preceded by a separator
__ jmp(&loop_3_entry);
// Loop condition: while (index < length).
__ bind(&loop_3);
// Each iteration of the loop concatenates one string to the result.
// Live values in registers:
// index: which element of the elements array we are adding to the result.
// result_pos: the position to which we are currently copying characters.
// Copy the separator to the result.
__ mov(string, separator_operand);
__ mov(string_length,
FieldOperand(string, String::kLengthOffset));
__ shr(string_length, 1);
__ lea(string,
FieldOperand(string, SeqAsciiString::kHeaderSize));
__ CopyBytes(string, result_pos, string_length, scratch);
__ bind(&loop_3_entry);
// Get string = array[index].
__ mov(string, FieldOperand(elements, index,
times_pointer_size,
FixedArray::kHeaderSize));
__ mov(string_length,
FieldOperand(string, String::kLengthOffset));
__ shr(string_length, 1);
__ lea(string,
FieldOperand(string, SeqAsciiString::kHeaderSize));
__ CopyBytes(string, result_pos, string_length, scratch);
__ add(Operand(index), Immediate(1));
__ cmp(index, array_length_operand);
__ j(less, &loop_3); // End while (index < length).
__ jmp(&done);
__ bind(&bailout);
__ mov(result, Factory::undefined_value());
__ mov(result_operand, Factory::undefined_value());
__ bind(&done);
__ mov(eax, result);
__ mov(eax, result_operand);
// Drop temp values from the stack, and restore context register.
__ add(Operand(esp), Immediate(5 * kPointerSize));
__ add(Operand(esp), Immediate(3 * kPointerSize));
__ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
context()->Plug(eax);

94
src/ia32/macro-assembler-ia32.cc
View File

@ -877,55 +877,53 @@ void MacroAssembler::AllocateAsciiConsString(Register result,
Immediate(Factory::cons_ascii_string_map()));
}
// All registers must be distinct. Only current_string needs valid contents
// on entry. All registers may be invalid on exit. result_operand is
// unchanged, padding_chars is updated correctly.
void MacroAssembler::AppendStringToTopOfNewSpace(
Register current_string, // Tagged pointer to string to copy.
Register current_string_length,
Register result_pos,
Register scratch,
Register new_padding_chars,
Operand operand_result,
Operand operand_padding_chars,
Label* bailout) {
mov(current_string_length,
FieldOperand(current_string, String::kLengthOffset));
shr(current_string_length, 1);
sub(current_string_length, operand_padding_chars);
mov(new_padding_chars, current_string_length);
add(Operand(current_string_length), Immediate(kObjectAlignmentMask));
and_(Operand(current_string_length), Immediate(~kObjectAlignmentMask));
sub(new_padding_chars, Operand(current_string_length));
neg(new_padding_chars);
// We need an allocation even if current_string_length is 0, to fetch
// result_pos. Consider using a faster fetch of result_pos in that case.
AllocateInNewSpace(current_string_length, result_pos, scratch, no_reg,
bailout, NO_ALLOCATION_FLAGS);
sub(result_pos, operand_padding_chars);
mov(operand_padding_chars, new_padding_chars);
Register scratch_2 = new_padding_chars; // Used to compute total length.
// Copy string to the end of result.
mov(current_string_length,
FieldOperand(current_string, String::kLengthOffset));
mov(scratch, operand_result);
mov(scratch_2, current_string_length);
add(scratch_2, FieldOperand(scratch, String::kLengthOffset));
mov(FieldOperand(scratch, String::kLengthOffset), scratch_2);
shr(current_string_length, 1);
lea(current_string,
FieldOperand(current_string, SeqAsciiString::kHeaderSize));
// Loop condition: while (--current_string_length >= 0).
Label copy_loop;
Label copy_loop_entry;
jmp(&copy_loop_entry);
bind(&copy_loop);
mov_b(scratch, Operand(current_string, current_string_length, times_1, 0));
mov_b(Operand(result_pos, current_string_length, times_1, 0), scratch);
bind(&copy_loop_entry);
sub(Operand(current_string_length), Immediate(1));
j(greater_equal, &copy_loop);
// Copy memory, byte-by-byte, from source to destination. Not optimized for
// long or aligned copies. The contents of scratch and length are destroyed.
// Source and destination are incremented by length.
// Many variants of movsb, loop unrolling, word moves, and indexed operands
// have been tried here already, and this is fastest.
// A simpler loop is faster on small copies, but 30% slower on large ones.
// The cld() instruction must have been emitted, to set the direction flag(),
// before calling this function.
void MacroAssembler::CopyBytes(Register source,
Register destination,
Register length,
Register scratch) {
Label loop, done, short_string, short_loop;
// Experimentation shows that the short string loop is faster if length < 10.
cmp(Operand(length), Immediate(10));
j(less_equal, &short_string);
ASSERT(source.is(esi));
ASSERT(destination.is(edi));
ASSERT(length.is(ecx));
// Because source is 4-byte aligned in our uses of this function,
// we keep source aligned for the rep_movs call by copying the odd bytes
// at the end of the ranges.
mov(scratch, Operand(source, length, times_1, -4));
mov(Operand(destination, length, times_1, -4), scratch);
mov(scratch, ecx);
shr(ecx, 2);
rep_movs();
and_(Operand(scratch), Immediate(0x3));
add(destination, Operand(scratch));
jmp(&done);
bind(&short_string);
test(length, Operand(length));
j(zero, &done);
bind(&short_loop);
mov_b(scratch, Operand(source, 0));
mov_b(Operand(destination, 0), scratch);
inc(source);
inc(destination);
dec(length);
j(not_zero, &short_loop);
bind(&done);
}

23
src/ia32/macro-assembler-ia32.h
View File

@ -386,22 +386,13 @@ class MacroAssembler: public Assembler {
Register scratch2,
Label* gc_required);
// All registers must be distinct. Only current_string needs valid contents
// on entry. All registers may be invalid on exit. result_operand is
// unchanged, padding_chars is updated correctly.
// The top of new space must contain a sequential ascii string with
// padding_chars bytes free in its top word. The sequential ascii string
// current_string is concatenated to it, allocating the necessary amount
// of new memory.
void AppendStringToTopOfNewSpace(
Register current_string, // Tagged pointer to string to copy.
Register current_string_length,
Register result_pos,
Register scratch,
Register new_padding_chars,
Operand operand_result,
Operand operand_padding_chars,
Label* bailout);
// Copy memory, byte-by-byte, from source to destination. Not optimized for
// long or aligned copies.
// The contents of index and scratch are destroyed.
void CopyBytes(Register source,
Register destination,
Register length,
Register scratch);
// ---------------------------------------------------------------------------
// Support functions.