// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/arm/codegen-arm.h"
#if V8_TARGET_ARCH_ARM
#include <memory>
#include "src/arm/simulator-arm.h"
#include "src/codegen.h"
#include "src/macro-assembler.h"
namespace v8 {
namespace internal {
#define __ masm.
#if defined(V8_HOST_ARCH_ARM)
MemCopyUint8Function CreateMemCopyUint8Function(Isolate* isolate,
MemCopyUint8Function stub) {
#if defined(USE_SIMULATOR)
return stub;
#else
size_t actual_size;
byte* buffer =
static_cast<byte*>(base::OS::Allocate(1 * KB, &actual_size, true));
if (buffer == nullptr) return stub;
MacroAssembler masm(isolate, buffer, static_cast<int>(actual_size),
CodeObjectRequired::kNo);
Register dest = r0;
Register src = r1;
Register chars = r2;
Register temp1 = r3;
Label less_4;
if (CpuFeatures::IsSupported(NEON)) {
CpuFeatureScope scope(&masm, NEON);
Label loop, less_256, less_128, less_64, less_32, _16_or_less, _8_or_less;
Label size_less_than_8;
__ pld(MemOperand(src, 0));
__ cmp(chars, Operand(8));
__ b(lt, &size_less_than_8);
__ cmp(chars, Operand(32));
__ b(lt, &less_32);
if (CpuFeatures::dcache_line_size() == 32) {
__ pld(MemOperand(src, 32));
}
__ cmp(chars, Operand(64));
__ b(lt, &less_64);
__ pld(MemOperand(src, 64));
if (CpuFeatures::dcache_line_size() == 32) {
__ pld(MemOperand(src, 96));
}
__ cmp(chars, Operand(128));
__ b(lt, &less_128);
__ pld(MemOperand(src, 128));
if (CpuFeatures::dcache_line_size() == 32) {
__ pld(MemOperand(src, 160));
}
__ pld(MemOperand(src, 192));
if (CpuFeatures::dcache_line_size() == 32) {
__ pld(MemOperand(src, 224));
}
__ cmp(chars, Operand(256));
__ b(lt, &less_256);
__ sub(chars, chars, Operand(256));
__ bind(&loop);
__ pld(MemOperand(src, 256));
__ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
if (CpuFeatures::dcache_line_size() == 32) {
__ pld(MemOperand(src, 256));
}
__ vld1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(src, PostIndex));
__ sub(chars, chars, Operand(64), SetCC);
__ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
__ vst1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(dest, PostIndex));
__ b(ge, &loop);
__ add(chars, chars, Operand(256));
__ bind(&less_256);
__ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
__ vld1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(src, PostIndex));
__ sub(chars, chars, Operand(128));
__ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
__ vst1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(dest, PostIndex));
__ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
__ vld1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(src, PostIndex));
__ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
__ vst1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(dest, PostIndex));
__ cmp(chars, Operand(64));
__ b(lt, &less_64);
__ bind(&less_128);
__ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
__ vld1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(src, PostIndex));
__ sub(chars, chars, Operand(64));
__ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
__ vst1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(dest, PostIndex));
__ bind(&less_64);
__ cmp(chars, Operand(32));
__ b(lt, &less_32);
__ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
__ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
__ sub(chars, chars, Operand(32));
__ bind(&less_32);
__ cmp(chars, Operand(16));
__ b(le, &_16_or_less);
__ vld1(Neon8, NeonListOperand(d0, 2), NeonMemOperand(src, PostIndex));
__ vst1(Neon8, NeonListOperand(d0, 2), NeonMemOperand(dest, PostIndex));
__ sub(chars, chars, Operand(16));
__ bind(&_16_or_less);
__ cmp(chars, Operand(8));
__ b(le, &_8_or_less);
__ vld1(Neon8, NeonListOperand(d0), NeonMemOperand(src, PostIndex));
__ vst1(Neon8, NeonListOperand(d0), NeonMemOperand(dest, PostIndex));
__ sub(chars, chars, Operand(8));
// Do a last copy which may overlap with the previous copy (up to 8 bytes).
__ bind(&_8_or_less);
__ rsb(chars, chars, Operand(8));
__ sub(src, src, Operand(chars));
__ sub(dest, dest, Operand(chars));
__ vld1(Neon8, NeonListOperand(d0), NeonMemOperand(src));
__ vst1(Neon8, NeonListOperand(d0), NeonMemOperand(dest));
__ Ret();
__ bind(&size_less_than_8);
__ bic(temp1, chars, Operand(0x3), SetCC);
__ b(&less_4, eq);
__ ldr(temp1, MemOperand(src, 4, PostIndex));
__ str(temp1, MemOperand(dest, 4, PostIndex));
} else {
Register temp2 = ip;
Label loop;
__ bic(temp2, chars, Operand(0x3), SetCC);
__ b(&less_4, eq);
__ add(temp2, dest, temp2);
__ bind(&loop);
__ ldr(temp1, MemOperand(src, 4, PostIndex));
__ str(temp1, MemOperand(dest, 4, PostIndex));
__ cmp(dest, temp2);
__ b(&loop, ne);
}
__ bind(&less_4);
__ mov(chars, Operand(chars, LSL, 31), SetCC);
// bit0 => Z (ne), bit1 => C (cs)
__ ldrh(temp1, MemOperand(src, 2, PostIndex), cs);
__ strh(temp1, MemOperand(dest, 2, PostIndex), cs);
__ ldrb(temp1, MemOperand(src), ne);
__ strb(temp1, MemOperand(dest), ne);
__ Ret();
CodeDesc desc;
masm.GetCode(&desc);
DCHECK(!RelocInfo::RequiresRelocation(desc));
Assembler::FlushICache(isolate, buffer, actual_size);
base::OS::ProtectCode(buffer, actual_size);
return FUNCTION_CAST<MemCopyUint8Function>(buffer);
#endif
}
// Convert 8 to 16. The number of character to copy must be at least 8.
MemCopyUint16Uint8Function CreateMemCopyUint16Uint8Function(
Isolate* isolate, MemCopyUint16Uint8Function stub) {
#if defined(USE_SIMULATOR)
return stub;
#else
size_t actual_size;
byte* buffer =
static_cast<byte*>(base::OS::Allocate(1 * KB, &actual_size, true));
if (buffer == nullptr) return stub;
MacroAssembler masm(isolate, buffer, static_cast<int>(actual_size),
CodeObjectRequired::kNo);
Register dest = r0;
Register src = r1;
Register chars = r2;
if (CpuFeatures::IsSupported(NEON)) {
CpuFeatureScope scope(&masm, NEON);
Register temp = r3;
Label loop;
__ bic(temp, chars, Operand(0x7));
__ sub(chars, chars, Operand(temp));
__ add(temp, dest, Operand(temp, LSL, 1));
__ bind(&loop);
__ vld1(Neon8, NeonListOperand(d0), NeonMemOperand(src, PostIndex));
__ vmovl(NeonU8, q0, d0);
__ vst1(Neon16, NeonListOperand(d0, 2), NeonMemOperand(dest, PostIndex));
__ cmp(dest, temp);
__ b(&loop, ne);
// Do a last copy which will overlap with the previous copy (1 to 8 bytes).
__ rsb(chars, chars, Operand(8));
__ sub(src, src, Operand(chars));
__ sub(dest, dest, Operand(chars, LSL, 1));
__ vld1(Neon8, NeonListOperand(d0), NeonMemOperand(src));
__ vmovl(NeonU8, q0, d0);
__ vst1(Neon16, NeonListOperand(d0, 2), NeonMemOperand(dest));
__ Ret();
} else {
Register temp1 = r3;
Register temp2 = ip;
Register temp3 = lr;
Register temp4 = r4;
Label loop;
Label not_two;
__ Push(lr, r4);
__ bic(temp2, chars, Operand(0x3));
__ add(temp2, dest, Operand(temp2, LSL, 1));
__ bind(&loop);
__ ldr(temp1, MemOperand(src, 4, PostIndex));
__ uxtb16(temp3, temp1);
__ uxtb16(temp4, temp1, 8);
__ pkhbt(temp1, temp3, Operand(temp4, LSL, 16));
__ str(temp1, MemOperand(dest));
__ pkhtb(temp1, temp4, Operand(temp3, ASR, 16));
__ str(temp1, MemOperand(dest, 4));
__ add(dest, dest, Operand(8));
__ cmp(dest, temp2);
__ b(&loop, ne);
__ mov(chars, Operand(chars, LSL, 31), SetCC); // bit0 => ne, bit1 => cs
__ b(¬_two, cc);
__ ldrh(temp1, MemOperand(src, 2, PostIndex));
__ uxtb(temp3, temp1, 8);
__ mov(temp3, Operand(temp3, LSL, 16));
__ uxtab(temp3, temp3, temp1);
__ str(temp3, MemOperand(dest, 4, PostIndex));
__ bind(¬_two);
__ ldrb(temp1, MemOperand(src), ne);
__ strh(temp1, MemOperand(dest), ne);
__ Pop(pc, r4);
}
CodeDesc desc;
masm.GetCode(&desc);
Assembler::FlushICache(isolate, buffer, actual_size);
base::OS::ProtectCode(buffer, actual_size);
return FUNCTION_CAST<MemCopyUint16Uint8Function>(buffer);
#endif
}
#endif
UnaryMathFunctionWithIsolate CreateSqrtFunction(Isolate* isolate) {
#if defined(USE_SIMULATOR)
return nullptr;
#else
size_t actual_size;
byte* buffer =
static_cast<byte*>(base::OS::Allocate(1 * KB, &actual_size, true));
if (buffer == nullptr) return nullptr;
MacroAssembler masm(isolate, buffer, static_cast<int>(actual_size),
CodeObjectRequired::kNo);
__ MovFromFloatParameter(d0);
__ vsqrt(d0, d0);
__ MovToFloatResult(d0);
__ Ret();
CodeDesc desc;
masm.GetCode(&desc);
DCHECK(!RelocInfo::RequiresRelocation(desc));
Assembler::FlushICache(isolate, buffer, actual_size);
base::OS::ProtectCode(buffer, actual_size);
return FUNCTION_CAST<UnaryMathFunctionWithIsolate>(buffer);
#endif
}
#undef __
// -------------------------------------------------------------------------
// Platform-specific RuntimeCallHelper functions.
void StubRuntimeCallHelper::BeforeCall(MacroAssembler* masm) const {
masm->EnterFrame(StackFrame::INTERNAL);
DCHECK(!masm->has_frame());
masm->set_has_frame(true);
}
void StubRuntimeCallHelper::AfterCall(MacroAssembler* masm) const {
masm->LeaveFrame(StackFrame::INTERNAL);
DCHECK(masm->has_frame());
masm->set_has_frame(false);
}
// -------------------------------------------------------------------------
// Code generators
#define __ ACCESS_MASM(masm)
void ElementsTransitionGenerator::GenerateMapChangeElementsTransition(
MacroAssembler* masm,
Register receiver,
Register key,
Register value,
Register target_map,
AllocationSiteMode mode,
Label* allocation_memento_found) {
Register scratch_elements = r4;
DCHECK(!AreAliased(receiver, key, value, target_map,
scratch_elements));
if (mode == TRACK_ALLOCATION_SITE) {
DCHECK(allocation_memento_found != NULL);
__ JumpIfJSArrayHasAllocationMemento(
receiver, scratch_elements, allocation_memento_found);
}
// Set transitioned map.
__ str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset));
__ RecordWriteField(receiver,
HeapObject::kMapOffset,
target_map,
r9,
kLRHasNotBeenSaved,
kDontSaveFPRegs,
EMIT_REMEMBERED_SET,
OMIT_SMI_CHECK);
}
void ElementsTransitionGenerator::GenerateSmiToDouble(
MacroAssembler* masm,
Register receiver,
Register key,
Register value,
Register target_map,
AllocationSiteMode mode,
Label* fail) {
// Register lr contains the return address.
Label loop, entry, convert_hole, gc_required, only_change_map, done;
Register elements = r4;
Register length = r5;
Register array = r6;
Register array_end = array;
// target_map parameter can be clobbered.
Register scratch1 = target_map;
Register scratch2 = r9;
// Verify input registers don't conflict with locals.
DCHECK(!AreAliased(receiver, key, value, target_map,
elements, length, array, scratch2));
if (mode == TRACK_ALLOCATION_SITE) {
__ JumpIfJSArrayHasAllocationMemento(receiver, elements, fail);
}
// Check for empty arrays, which only require a map transition and no changes
// to the backing store.
__ ldr(elements, FieldMemOperand(receiver, JSObject::kElementsOffset));
__ CompareRoot(elements, Heap::kEmptyFixedArrayRootIndex);
__ b(eq, &only_change_map);
__ push(lr);
__ ldr(length, FieldMemOperand(elements, FixedArray::kLengthOffset));
// length: number of elements (smi-tagged)
// Allocate new FixedDoubleArray.
// Use lr as a temporary register.
__ mov(lr, Operand(length, LSL, 2));
__ add(lr, lr, Operand(FixedDoubleArray::kHeaderSize));
__ Allocate(lr, array, elements, scratch2, &gc_required, DOUBLE_ALIGNMENT);
__ sub(array, array, Operand(kHeapObjectTag));
// array: destination FixedDoubleArray, not tagged as heap object.
__ ldr(elements, FieldMemOperand(receiver, JSObject::kElementsOffset));
// r4: source FixedArray.
// Set destination FixedDoubleArray's length and map.
__ LoadRoot(scratch2, Heap::kFixedDoubleArrayMapRootIndex);
__ str(length, MemOperand(array, FixedDoubleArray::kLengthOffset));
// Update receiver's map.
__ str(scratch2, MemOperand(array, HeapObject::kMapOffset));
__ str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset));
__ RecordWriteField(receiver,
HeapObject::kMapOffset,
target_map,
scratch2,
kLRHasBeenSaved,
kDontSaveFPRegs,
OMIT_REMEMBERED_SET,
OMIT_SMI_CHECK);
// Replace receiver's backing store with newly created FixedDoubleArray.
__ add(scratch1, array, Operand(kHeapObjectTag));
__ str(scratch1, FieldMemOperand(receiver, JSObject::kElementsOffset));
__ RecordWriteField(receiver,
JSObject::kElementsOffset,
scratch1,
scratch2,
kLRHasBeenSaved,
kDontSaveFPRegs,
EMIT_REMEMBERED_SET,
OMIT_SMI_CHECK);
// Prepare for conversion loop.
__ add(scratch1, elements, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
__ add(scratch2, array, Operand(FixedDoubleArray::kHeaderSize));
__ add(array_end, scratch2, Operand(length, LSL, 2));
// Repurpose registers no longer in use.
Register hole_lower = elements;
Register hole_upper = length;
__ mov(hole_lower, Operand(kHoleNanLower32));
__ mov(hole_upper, Operand(kHoleNanUpper32));
// scratch1: begin of source FixedArray element fields, not tagged
// hole_lower: kHoleNanLower32
// hole_upper: kHoleNanUpper32
// array_end: end of destination FixedDoubleArray, not tagged
// scratch2: begin of FixedDoubleArray element fields, not tagged
__ b(&entry);
__ bind(&only_change_map);
__ str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset));
__ RecordWriteField(receiver,
HeapObject::kMapOffset,
target_map,
scratch2,
kLRHasNotBeenSaved,
kDontSaveFPRegs,
OMIT_REMEMBERED_SET,
OMIT_SMI_CHECK);
__ b(&done);
// Call into runtime if GC is required.
__ bind(&gc_required);
__ pop(lr);
__ b(fail);
// Convert and copy elements.
__ bind(&loop);
__ ldr(lr, MemOperand(scratch1, 4, PostIndex));
// lr: current element
__ UntagAndJumpIfNotSmi(lr, lr, &convert_hole);
// Normal smi, convert to double and store.
__ vmov(s0, lr);
__ vcvt_f64_s32(d0, s0);
__ vstr(d0, scratch2, 0);
__ add(scratch2, scratch2, Operand(8));
__ b(&entry);
// Hole found, store the-hole NaN.
__ bind(&convert_hole);
if (FLAG_debug_code) {
// Restore a "smi-untagged" heap object.
__ SmiTag(lr);
__ orr(lr, lr, Operand(1));
__ CompareRoot(lr, Heap::kTheHoleValueRootIndex);
__ Assert(eq, kObjectFoundInSmiOnlyArray);
}
__ Strd(hole_lower, hole_upper, MemOperand(scratch2, 8, PostIndex));
__ bind(&entry);
__ cmp(scratch2, array_end);
__ b(lt, &loop);
__ pop(lr);
__ bind(&done);
}
void ElementsTransitionGenerator::GenerateDoubleToObject(
MacroAssembler* masm,
Register receiver,
Register key,
Register value,
Register target_map,
AllocationSiteMode mode,
Label* fail) {
// Register lr contains the return address.
Label entry, loop, convert_hole, gc_required, only_change_map;
Register elements = r4;
Register array = r6;
Register length = r5;
Register scratch = r9;
// Verify input registers don't conflict with locals.
DCHECK(!AreAliased(receiver, key, value, target_map,
elements, array, length, scratch));
if (mode == TRACK_ALLOCATION_SITE) {
__ JumpIfJSArrayHasAllocationMemento(receiver, elements, fail);
}
// Check for empty arrays, which only require a map transition and no changes
// to the backing store.
__ ldr(elements, FieldMemOperand(receiver, JSObject::kElementsOffset));
__ CompareRoot(elements, Heap::kEmptyFixedArrayRootIndex);
__ b(eq, &only_change_map);
__ push(lr);
__ Push(target_map, receiver, key, value);
__ ldr(length, FieldMemOperand(elements, FixedArray::kLengthOffset));
// elements: source FixedDoubleArray
// length: number of elements (smi-tagged)
// Allocate new FixedArray.
// Re-use value and target_map registers, as they have been saved on the
// stack.
Register array_size = value;
Register allocate_scratch = target_map;
__ mov(array_size, Operand(FixedDoubleArray::kHeaderSize));
__ add(array_size, array_size, Operand(length, LSL, 1));
__ Allocate(array_size, array, allocate_scratch, scratch, &gc_required,
NO_ALLOCATION_FLAGS);
// array: destination FixedArray, tagged as heap object
// Set destination FixedDoubleArray's length and map.
__ LoadRoot(scratch, Heap::kFixedArrayMapRootIndex);
__ str(length, FieldMemOperand(array, FixedDoubleArray::kLengthOffset));
__ str(scratch, FieldMemOperand(array, HeapObject::kMapOffset));
__ sub(array, array, Operand(kHeapObjectTag));
// Prepare for conversion loop.
Register src_elements = elements;
Register dst_elements = target_map;
Register dst_end = length;
Register heap_number_map = scratch;
__ add(src_elements, elements,
Operand(FixedDoubleArray::kHeaderSize - kHeapObjectTag + 4));
__ add(dst_elements, array, Operand(FixedArray::kHeaderSize));
__ add(dst_end, dst_elements, Operand(length, LSL, 1));
// Allocating heap numbers in the loop below can fail and cause a jump to
// gc_required. We can't leave a partly initialized FixedArray behind,
// so pessimistically fill it with holes now.
Label initialization_loop, initialization_loop_entry;
__ LoadRoot(scratch, Heap::kTheHoleValueRootIndex);
__ b(&initialization_loop_entry);
__ bind(&initialization_loop);
__ str(scratch, MemOperand(dst_elements, kPointerSize, PostIndex));
__ bind(&initialization_loop_entry);
__ cmp(dst_elements, dst_end);
__ b(lt, &initialization_loop);
__ add(dst_elements, array, Operand(FixedArray::kHeaderSize));
__ add(array, array, Operand(kHeapObjectTag));
__ LoadRoot(heap_number_map, Heap::kHeapNumberMapRootIndex);
// Using offsetted addresses in src_elements to fully take advantage of
// post-indexing.
// dst_elements: begin of destination FixedArray element fields, not tagged
// src_elements: begin of source FixedDoubleArray element fields,
// not tagged, +4
// dst_end: end of destination FixedArray, not tagged
// array: destination FixedArray
// heap_number_map: heap number map
__ b(&entry);
// Call into runtime if GC is required.
__ bind(&gc_required);
__ Pop(target_map, receiver, key, value);
__ pop(lr);
__ b(fail);
__ bind(&loop);
Register upper_bits = key;
__ ldr(upper_bits, MemOperand(src_elements, 8, PostIndex));
// upper_bits: current element's upper 32 bit
// src_elements: address of next element's upper 32 bit
__ cmp(upper_bits, Operand(kHoleNanUpper32));
__ b(eq, &convert_hole);
// Non-hole double, copy value into a heap number.
Register heap_number = receiver;
Register scratch2 = value;
__ AllocateHeapNumber(heap_number, scratch2, lr, heap_number_map,
&gc_required);
// heap_number: new heap number
__ ldr(scratch2, MemOperand(src_elements, 12, NegOffset));
__ Strd(scratch2, upper_bits,
FieldMemOperand(heap_number, HeapNumber::kValueOffset));
__ mov(scratch2, dst_elements);
__ str(heap_number, MemOperand(dst_elements, 4, PostIndex));
__ RecordWrite(array,
scratch2,
heap_number,
kLRHasBeenSaved,
kDontSaveFPRegs,
EMIT_REMEMBERED_SET,
OMIT_SMI_CHECK);
__ b(&entry);
// Replace the-hole NaN with the-hole pointer.
__ bind(&convert_hole);
__ LoadRoot(scratch2, Heap::kTheHoleValueRootIndex);
__ str(scratch2, MemOperand(dst_elements, 4, PostIndex));
__ bind(&entry);
__ cmp(dst_elements, dst_end);
__ b(lt, &loop);
__ Pop(target_map, receiver, key, value);
// Replace receiver's backing store with newly created and filled FixedArray.
__ str(array, FieldMemOperand(receiver, JSObject::kElementsOffset));
__ RecordWriteField(receiver,
JSObject::kElementsOffset,
array,
scratch,
kLRHasBeenSaved,
kDontSaveFPRegs,
EMIT_REMEMBERED_SET,
OMIT_SMI_CHECK);
__ pop(lr);
__ bind(&only_change_map);
// Update receiver's map.
__ str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset));
__ RecordWriteField(receiver,
HeapObject::kMapOffset,
target_map,
scratch,
kLRHasNotBeenSaved,
kDontSaveFPRegs,
OMIT_REMEMBERED_SET,
OMIT_SMI_CHECK);
}
void StringCharLoadGenerator::Generate(MacroAssembler* masm,
Register string,
Register index,
Register result,
Label* call_runtime) {
// Fetch the instance type of the receiver into result register.
__ ldr(result, FieldMemOperand(string, HeapObject::kMapOffset));
__ ldrb(result, FieldMemOperand(result, Map::kInstanceTypeOffset));
// We need special handling for indirect strings.
Label check_sequential;
__ tst(result, Operand(kIsIndirectStringMask));
__ b(eq, &check_sequential);
// Dispatch on the indirect string shape: slice or cons.
Label cons_string;
__ tst(result, Operand(kSlicedNotConsMask));
__ b(eq, &cons_string);
// Handle slices.
Label indirect_string_loaded;
__ ldr(result, FieldMemOperand(string, SlicedString::kOffsetOffset));
__ ldr(string, FieldMemOperand(string, SlicedString::kParentOffset));
__ add(index, index, Operand::SmiUntag(result));
__ jmp(&indirect_string_loaded);
// Handle cons strings.
// Check whether the right hand side is the empty string (i.e. if
// this is really a flat string in a cons string). If that is not
// the case we would rather go to the runtime system now to flatten
// the string.
__ bind(&cons_string);
__ ldr(result, FieldMemOperand(string, ConsString::kSecondOffset));
__ CompareRoot(result, Heap::kempty_stringRootIndex);
__ b(ne, call_runtime);
// Get the first of the two strings and load its instance type.
__ ldr(string, FieldMemOperand(string, ConsString::kFirstOffset));
__ bind(&indirect_string_loaded);
__ ldr(result, FieldMemOperand(string, HeapObject::kMapOffset));
__ ldrb(result, FieldMemOperand(result, Map::kInstanceTypeOffset));
// Distinguish sequential and external strings. Only these two string
// representations can reach here (slices and flat cons strings have been
// reduced to the underlying sequential or external string).
Label external_string, check_encoding;
__ bind(&check_sequential);
STATIC_ASSERT(kSeqStringTag == 0);
__ tst(result, Operand(kStringRepresentationMask));
__ b(ne, &external_string);
// Prepare sequential strings
STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize);
__ add(string,
string,
Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
__ jmp(&check_encoding);
// Handle external strings.
__ bind(&external_string);
if (FLAG_debug_code) {
// Assert that we do not have a cons or slice (indirect strings) here.
// Sequential strings have already been ruled out.
__ tst(result, Operand(kIsIndirectStringMask));
__ Assert(eq, kExternalStringExpectedButNotFound);
}
// Rule out short external strings.
STATIC_ASSERT(kShortExternalStringTag != 0);
__ tst(result, Operand(kShortExternalStringMask));
__ b(ne, call_runtime);
__ ldr(string, FieldMemOperand(string, ExternalString::kResourceDataOffset));
Label one_byte, done;
__ bind(&check_encoding);
STATIC_ASSERT(kTwoByteStringTag == 0);
__ tst(result, Operand(kStringEncodingMask));
__ b(ne, &one_byte);
// Two-byte string.
__ ldrh(result, MemOperand(string, index, LSL, 1));
__ jmp(&done);
__ bind(&one_byte);
// One-byte string.
__ ldrb(result, MemOperand(string, index));
__ bind(&done);
}
#undef __
#ifdef DEBUG
// add(r0, pc, Operand(-8))
static const uint32_t kCodeAgePatchFirstInstruction = 0xe24f0008;
#endif
CodeAgingHelper::CodeAgingHelper(Isolate* isolate) {
USE(isolate);
DCHECK(young_sequence_.length() == kNoCodeAgeSequenceLength);
// Since patcher is a large object, allocate it dynamically when needed,
// to avoid overloading the stack in stress conditions.
// DONT_FLUSH is used because the CodeAgingHelper is initialized early in
// the process, before ARM simulator ICache is setup.
std::unique_ptr<CodePatcher> patcher(
new CodePatcher(isolate, young_sequence_.start(),
young_sequence_.length() / Assembler::kInstrSize,
CodePatcher::DONT_FLUSH));
PredictableCodeSizeScope scope(patcher->masm(), young_sequence_.length());
patcher->masm()->PushStandardFrame(r1);
patcher->masm()->nop(ip.code());
}
#ifdef DEBUG
bool CodeAgingHelper::IsOld(byte* candidate) const {
return Memory::uint32_at(candidate) == kCodeAgePatchFirstInstruction;
}
#endif
bool Code::IsYoungSequence(Isolate* isolate, byte* sequence) {
bool result = isolate->code_aging_helper()->IsYoung(sequence);
DCHECK(result || isolate->code_aging_helper()->IsOld(sequence));
return result;
}
void Code::GetCodeAgeAndParity(Isolate* isolate, byte* sequence, Age* age,
MarkingParity* parity) {
if (IsYoungSequence(isolate, sequence)) {
*age = kNoAgeCodeAge;
*parity = NO_MARKING_PARITY;
} else {
Address target_address = Memory::Address_at(
sequence + (kNoCodeAgeSequenceLength - Assembler::kInstrSize));
Code* stub = GetCodeFromTargetAddress(target_address);
GetCodeAgeAndParity(stub, age, parity);
}
}
void Code::PatchPlatformCodeAge(Isolate* isolate,
byte* sequence,
Code::Age age,
MarkingParity parity) {
uint32_t young_length = isolate->code_aging_helper()->young_sequence_length();
if (age == kNoAgeCodeAge) {
isolate->code_aging_helper()->CopyYoungSequenceTo(sequence);
Assembler::FlushICache(isolate, sequence, young_length);
} else {
Code* stub = GetCodeAgeStub(isolate, age, parity);
CodePatcher patcher(isolate, sequence,
young_length / Assembler::kInstrSize);
patcher.masm()->add(r0, pc, Operand(-8));
patcher.masm()->ldr(pc, MemOperand(pc, -4));
patcher.masm()->emit_code_stub_address(stub);
}
}
} // namespace internal
} // namespace v8
#endif // V8_TARGET_ARCH_ARM