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

Issue 2071020: Reverting r4685, r4686, r4687 (Closed) Base URL: http://v8.googlecode.com/svn/branches/bleeding_edge/
Patch Set: Created 10 years, 7 months ago
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Index: src/arm/macro-assembler-arm.cc
===================================================================
--- src/arm/macro-assembler-arm.cc (revision 4686)
+++ src/arm/macro-assembler-arm.cc (working copy)
@@ -252,21 +252,63 @@
bind(&not_in_new_space);
}
- mov(ip, Operand(Page::kPageAlignmentMask)); // Load mask only once.
+ // This is how much we shift the remembered set bit offset to get the
+ // offset of the word in the remembered set. We divide by kBitsPerInt (32,
+ // shift right 5) and then multiply by kIntSize (4, shift left 2).
+ const int kRSetWordShift = 3;
- // Calculate region number.
- add(offset, object, Operand(offset)); // Add offset into the object.
- and_(offset, offset, Operand(ip)); // Offset into page of the object.
- mov(offset, Operand(offset, LSR, Page::kRegionSizeLog2));
+ Label fast;
- // Calculate page address.
+ // Compute the bit offset in the remembered set.
+ // object: heap object pointer (with tag)
+ // offset: offset to store location from the object
+ mov(ip, Operand(Page::kPageAlignmentMask)); // load mask only once
+ and_(scratch, object, Operand(ip)); // offset into page of the object
+ add(offset, scratch, Operand(offset)); // add offset into the object
+ mov(offset, Operand(offset, LSR, kObjectAlignmentBits));
+
+ // Compute the page address from the heap object pointer.
+ // object: heap object pointer (with tag)
+ // offset: bit offset of store position in the remembered set
bic(object, object, Operand(ip));
- // Mark region dirty.
- ldr(scratch, MemOperand(object, Page::kDirtyFlagOffset));
+ // If the bit offset lies beyond the normal remembered set range, it is in
+ // the extra remembered set area of a large object.
+ // object: page start
+ // offset: bit offset of store position in the remembered set
+ cmp(offset, Operand(Page::kPageSize / kPointerSize));
+ b(lt, &fast);
+
+ // Adjust the bit offset to be relative to the start of the extra
+ // remembered set and the start address to be the address of the extra
+ // remembered set.
+ sub(offset, offset, Operand(Page::kPageSize / kPointerSize));
+ // Load the array length into 'scratch' and multiply by four to get the
+ // size in bytes of the elements.
+ ldr(scratch, MemOperand(object, Page::kObjectStartOffset
+ + FixedArray::kLengthOffset));
+ mov(scratch, Operand(scratch, LSL, kObjectAlignmentBits));
+ // Add the page header (including remembered set), array header, and array
+ // body size to the page address.
+ add(object, object, Operand(Page::kObjectStartOffset
+ + FixedArray::kHeaderSize));
+ add(object, object, Operand(scratch));
+
+ bind(&fast);
+ // Get address of the rset word.
+ // object: start of the remembered set (page start for the fast case)
+ // offset: bit offset of store position in the remembered set
+ bic(scratch, offset, Operand(kBitsPerInt - 1)); // clear the bit offset
+ add(object, object, Operand(scratch, LSR, kRSetWordShift));
+ // Get bit offset in the rset word.
+ // object: address of remembered set word
+ // offset: bit offset of store position
+ and_(offset, offset, Operand(kBitsPerInt - 1));
+
+ ldr(scratch, MemOperand(object));
mov(ip, Operand(1));
orr(scratch, scratch, Operand(ip, LSL, offset));
- str(scratch, MemOperand(object, Page::kDirtyFlagOffset));
+ str(scratch, MemOperand(object));
}
@@ -294,7 +336,7 @@
Label done;
// First, test that the object is not in the new space. We cannot set
- // region marks for new space pages.
+ // remembered set bits in the new space.
InNewSpace(object, scratch, eq, &done);
// Record the actual write.
@@ -577,7 +619,6 @@
ldr(expected_reg,
FieldMemOperand(code_reg,
SharedFunctionInfo::kFormalParameterCountOffset));
- mov(expected_reg, Operand(expected_reg, ASR, kSmiTagSize));
ldr(code_reg,
MemOperand(code_reg, SharedFunctionInfo::kCodeOffset - kHeapObjectTag));
add(code_reg, code_reg, Operand(Code::kHeaderSize - kHeapObjectTag));
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