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Unified Diff: src/x64/macro-assembler-x64.cc

Issue 2144006: Cardmarking writebarrier. (Closed)
Patch Set: change NewSpace and SemiSpace Contains to match HasHeapObjectTag Created 10 years, 7 months ago
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Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 065b61693f20c22360a4b98915b2ed15f454913b..4e0e01e0fd7bdaf1a5f037e62b108aeaaf3bc096 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -90,58 +90,21 @@ void MacroAssembler::RecordWriteHelper(Register object,
bind(&not_in_new_space);
}
- Label fast;
-
// Compute the page start address from the heap object pointer, and reuse
// the 'object' register for it.
- ASSERT(is_int32(~Page::kPageAlignmentMask));
- and_(object,
- Immediate(static_cast<int32_t>(~Page::kPageAlignmentMask)));
- Register page_start = object;
-
- // Compute the bit addr in the remembered set/index of the pointer in the
- // page. Reuse 'addr' as pointer_offset.
- subq(addr, page_start);
- shr(addr, Immediate(kPointerSizeLog2));
- Register pointer_offset = addr;
-
- // If the bit offset lies beyond the normal remembered set range, it is in
- // the extra remembered set area of a large object.
- cmpq(pointer_offset, Immediate(Page::kPageSize / kPointerSize));
- j(below, &fast);
-
- // We have a large object containing pointers. It must be a FixedArray.
-
- // Adjust 'page_start' so that addressing using 'pointer_offset' hits the
- // extra remembered set after the large object.
-
- // Load the array length into 'scratch'.
- movl(scratch,
- Operand(page_start,
- Page::kObjectStartOffset + FixedArray::kLengthOffset));
- Register array_length = scratch;
-
- // Extra remembered set starts right after the large object (a FixedArray), at
- // page_start + kObjectStartOffset + objectSize
- // where objectSize is FixedArray::kHeaderSize + kPointerSize * array_length.
- // Add the delta between the end of the normal RSet and the start of the
- // extra RSet to 'page_start', so that addressing the bit using
- // 'pointer_offset' hits the extra RSet words.
- lea(page_start,
- Operand(page_start, array_length, times_pointer_size,
- Page::kObjectStartOffset + FixedArray::kHeaderSize
- - Page::kRSetEndOffset));
-
- // NOTE: For now, we use the bit-test-and-set (bts) x86 instruction
- // to limit code size. We should probably evaluate this decision by
- // measuring the performance of an equivalent implementation using
- // "simpler" instructions
- bind(&fast);
- bts(Operand(page_start, Page::kRSetOffset), pointer_offset);
-}
-
-
-// Set the remembered set bit for [object+offset].
+ and_(object, Immediate(~Page::kPageAlignmentMask));
+
+ // Compute number of region covering addr. See Page::GetRegionNumberForAddress
+ // method for more details.
+ and_(addr, Immediate(Page::kPageAlignmentMask));
+ shrl(addr, Immediate(Page::kRegionSizeLog2));
+
+ // Set dirty mark for region.
+ bts(Operand(object, Page::kDirtyFlagOffset), addr);
+}
+
+
+// For page containing |object| mark region covering [object+offset] dirty.
// object is the object being stored into, value is the object being stored.
// If offset is zero, then the smi_index register contains the array index into
// the elements array represented as a smi. Otherwise it can be used as a
@@ -156,9 +119,8 @@ void MacroAssembler::RecordWrite(Register object,
// registers are rsi.
ASSERT(!object.is(rsi) && !value.is(rsi) && !smi_index.is(rsi));
- // First, check if a remembered set write is even needed. The tests below
- // catch stores of Smis and stores into young gen (which does not have space
- // for the remembered set bits).
+ // First, check if a write barrier is even needed. The tests below
+ // catch stores of Smis and stores into young gen.
Label done;
JumpIfSmi(value, &done);
@@ -191,8 +153,8 @@ void MacroAssembler::RecordWriteNonSmi(Register object,
bind(&okay);
}
- // Test that the object address is not in the new space. We cannot
- // set remembered set bits in the new space.
+ // Test that the object address is not in the new space. We cannot
+ // update page dirty marks for new space pages.
InNewSpace(object, scratch, equal, &done);
// The offset is relative to a tagged or untagged HeapObject pointer,
@@ -201,48 +163,19 @@ void MacroAssembler::RecordWriteNonSmi(Register object,
ASSERT(IsAligned(offset, kPointerSize) ||
IsAligned(offset + kHeapObjectTag, kPointerSize));
- // We use optimized write barrier code if the word being written to is not in
- // a large object page, or is in the first "page" of a large object page.
- // We make sure that an offset is inside the right limits whether it is
- // tagged or untagged.
- if ((offset > 0) && (offset < Page::kMaxHeapObjectSize - kHeapObjectTag)) {
- // Compute the bit offset in the remembered set, leave it in 'scratch'.
- lea(scratch, Operand(object, offset));
- ASSERT(is_int32(Page::kPageAlignmentMask));
- and_(scratch, Immediate(static_cast<int32_t>(Page::kPageAlignmentMask)));
- shr(scratch, Immediate(kPointerSizeLog2));
-
- // Compute the page address from the heap object pointer, leave it in
- // 'object' (immediate value is sign extended).
- and_(object, Immediate(~Page::kPageAlignmentMask));
-
- // NOTE: For now, we use the bit-test-and-set (bts) x86 instruction
- // to limit code size. We should probably evaluate this decision by
- // measuring the performance of an equivalent implementation using
- // "simpler" instructions
- bts(Operand(object, Page::kRSetOffset), scratch);
+ Register dst = smi_index;
+ if (offset != 0) {
+ lea(dst, Operand(object, offset));
} else {
- Register dst = smi_index;
- if (offset != 0) {
- lea(dst, Operand(object, offset));
- } else {
- // array access: calculate the destination address in the same manner as
- // KeyedStoreIC::GenerateGeneric.
- SmiIndex index = SmiToIndex(smi_index, smi_index, kPointerSizeLog2);
- lea(dst, FieldOperand(object,
- index.reg,
- index.scale,
- FixedArray::kHeaderSize));
- }
- // If we are already generating a shared stub, not inlining the
- // record write code isn't going to save us any memory.
- if (generating_stub()) {
- RecordWriteHelper(object, dst, scratch);
- } else {
- RecordWriteStub stub(object, dst, scratch);
- CallStub(&stub);
- }
+ // array access: calculate the destination address in the same manner as
+ // KeyedStoreIC::GenerateGeneric.
+ SmiIndex index = SmiToIndex(smi_index, smi_index, kPointerSizeLog2);
+ lea(dst, FieldOperand(object,
+ index.reg,
+ index.scale,
+ FixedArray::kHeaderSize));
}
+ RecordWriteHelper(object, dst, scratch);
bind(&done);
@@ -644,6 +577,18 @@ void MacroAssembler::PositiveSmiTimesPowerOfTwoToInteger64(Register dst,
}
+void MacroAssembler::PositiveSmiDivPowerOfTwoToInteger32(Register dst,
+ Register src,
+ int power) {
+ ASSERT((0 <= power) && (power < 32));
+ if (dst.is(src)) {
+ shr(dst, Immediate(power + kSmiShift));
+ } else {
+ UNIMPLEMENTED(); // Not used.
+ }
+}
+
+
Condition MacroAssembler::CheckSmi(Register src) {
ASSERT_EQ(0, kSmiTag);
testb(src, Immediate(kSmiTagMask));
@@ -2607,7 +2552,7 @@ void MacroAssembler::AllocateTwoByteString(Register result,
movq(FieldOperand(result, HeapObject::kMapOffset), kScratchRegister);
Integer32ToSmi(scratch1, length);
movq(FieldOperand(result, String::kLengthOffset), scratch1);
- movl(FieldOperand(result, String::kHashFieldOffset),
+ movq(FieldOperand(result, String::kHashFieldOffset),
Immediate(String::kEmptyHashField));
}
@@ -2645,7 +2590,7 @@ void MacroAssembler::AllocateAsciiString(Register result,
movq(FieldOperand(result, HeapObject::kMapOffset), kScratchRegister);
Integer32ToSmi(scratch1, length);
movq(FieldOperand(result, String::kLengthOffset), scratch1);
- movl(FieldOperand(result, String::kHashFieldOffset),
+ movq(FieldOperand(result, String::kHashFieldOffset),
Immediate(String::kEmptyHashField));
}
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