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[HEAP] Remove SIMD 128 bit alignment from heap.

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LOG=N
BUG=v8:4124, v8:5948

Review-Url: https://codereview.chromium.org/2694063005
Cr-Commit-Position: refs/heads/master@{#43219}
This commit is contained in:
bbudge 2017-02-15 07:42:27 -08:00 committed by Commit bot
parent 67d087d577
commit 717c8f2c76
4 changed files with 18 additions and 125 deletions
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11
src/globals.h
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@ -370,10 +370,6 @@ const intptr_t kPointerAlignmentMask = kPointerAlignment - 1;
const intptr_t kDoubleAlignment = 8;
const intptr_t kDoubleAlignmentMask = kDoubleAlignment - 1;
// Desired alignment for 128 bit SIMD values.
const intptr_t kSimd128Alignment = 16;
const intptr_t kSimd128AlignmentMask = kSimd128Alignment - 1;
// Desired alignment for generated code is 32 bytes (to improve cache line
// utilization).
const int kCodeAlignmentBits = 5;
@ -516,12 +512,7 @@ enum AllocationSpace {
const int kSpaceTagSize = 3;
const int kSpaceTagMask = (1 << kSpaceTagSize) - 1;
enum AllocationAlignment {
kWordAligned,
kDoubleAligned,
kDoubleUnaligned,
kSimd128Unaligned
};
enum AllocationAlignment { kWordAligned, kDoubleAligned, kDoubleUnaligned };
// Possible outcomes for decisions.
enum class Decision : uint8_t { kUnknown, kTrue, kFalse };

6
src/heap/heap.cc
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@ -1970,8 +1970,6 @@ int Heap::GetMaximumFillToAlign(AllocationAlignment alignment) {
case kDoubleAligned:
case kDoubleUnaligned:
return kDoubleSize - kPointerSize;
case kSimd128Unaligned:
return kSimd128Size - kPointerSize;
default:
UNREACHABLE();
}
@ -1985,10 +1983,6 @@ int Heap::GetFillToAlign(Address address, AllocationAlignment alignment) {
return kPointerSize;
if (alignment == kDoubleUnaligned && (offset & kDoubleAlignmentMask) == 0)
return kDoubleSize - kPointerSize; // No fill if double is always aligned.
if (alignment == kSimd128Unaligned) {
return (kSimd128Size - (static_cast<int>(offset) + kPointerSize)) &
kSimd128AlignmentMask;
}
return 0;
}

2
src/snapshot/deserializer.h
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@ -84,7 +84,7 @@ class Deserializer : public SerializerDeserializer {
DCHECK_EQ(kWordAligned, next_alignment_);
int alignment = data - (kAlignmentPrefix - 1);
DCHECK_LE(kWordAligned, alignment);
DCHECK_LE(alignment, kSimd128Unaligned);
DCHECK_LE(alignment, kDoubleUnaligned);
next_alignment_ = static_cast<AllocationAlignment>(alignment);
}

124
test/cctest/heap/test-heap.cc
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@ -1869,16 +1869,12 @@ HEAP_TEST(TestSizeOfObjects) {
TEST(TestAlignmentCalculations) {
// Maximum fill amounts are consistent.
int maximum_double_misalignment = kDoubleSize - kPointerSize;
int maximum_simd128_misalignment = kSimd128Size - kPointerSize;
int max_word_fill = Heap::GetMaximumFillToAlign(kWordAligned);
CHECK_EQ(0, max_word_fill);
int max_double_fill = Heap::GetMaximumFillToAlign(kDoubleAligned);
CHECK_EQ(maximum_double_misalignment, max_double_fill);
int max_double_unaligned_fill = Heap::GetMaximumFillToAlign(kDoubleUnaligned);
CHECK_EQ(maximum_double_misalignment, max_double_unaligned_fill);
int max_simd128_unaligned_fill =
Heap::GetMaximumFillToAlign(kSimd128Unaligned);
CHECK_EQ(maximum_simd128_misalignment, max_simd128_unaligned_fill);
Address base = static_cast<Address>(NULL);
int fill = 0;
@ -1900,16 +1896,6 @@ TEST(TestAlignmentCalculations) {
CHECK_EQ(maximum_double_misalignment, fill);
fill = Heap::GetFillToAlign(base + kPointerSize, kDoubleUnaligned);
CHECK_EQ(0, fill);
// 128 bit SIMD types have 2 or 4 possible alignments, depending on platform.
fill = Heap::GetFillToAlign(base, kSimd128Unaligned);
CHECK_EQ((3 * kPointerSize) & kSimd128AlignmentMask, fill);
fill = Heap::GetFillToAlign(base + kPointerSize, kSimd128Unaligned);
CHECK_EQ((2 * kPointerSize) & kSimd128AlignmentMask, fill);
fill = Heap::GetFillToAlign(base + 2 * kPointerSize, kSimd128Unaligned);
CHECK_EQ(kPointerSize, fill);
fill = Heap::GetFillToAlign(base + 3 * kPointerSize, kSimd128Unaligned);
CHECK_EQ(0, fill);
}
@ -1977,42 +1963,6 @@ TEST(TestAlignedAllocation) {
filler->Size() == kPointerSize);
CHECK_EQ(kPointerSize + double_misalignment, *top_addr - start);
}
// Now test SIMD alignment. There are 2 or 4 possible alignments, depending
// on platform.
start = AlignNewSpace(kSimd128Unaligned, 0);
obj = NewSpaceAllocateAligned(kPointerSize, kSimd128Unaligned);
CHECK(IsAddressAligned(obj->address(), kSimd128Alignment, kPointerSize));
// There is no filler.
CHECK_EQ(kPointerSize, *top_addr - start);
start = AlignNewSpace(kSimd128Unaligned, kPointerSize);
obj = NewSpaceAllocateAligned(kPointerSize, kSimd128Unaligned);
CHECK(IsAddressAligned(obj->address(), kSimd128Alignment, kPointerSize));
// There is a filler object before the object.
filler = HeapObject::FromAddress(start);
CHECK(obj != filler && filler->IsFiller() &&
filler->Size() == kSimd128Size - kPointerSize);
CHECK_EQ(kPointerSize + kSimd128Size - kPointerSize, *top_addr - start);
if (double_misalignment) {
// Test the 2 other alignments possible on 32 bit platforms.
start = AlignNewSpace(kSimd128Unaligned, 2 * kPointerSize);
obj = NewSpaceAllocateAligned(kPointerSize, kSimd128Unaligned);
CHECK(IsAddressAligned(obj->address(), kSimd128Alignment, kPointerSize));
// There is a filler object before the object.
filler = HeapObject::FromAddress(start);
CHECK(obj != filler && filler->IsFiller() &&
filler->Size() == 2 * kPointerSize);
CHECK_EQ(kPointerSize + 2 * kPointerSize, *top_addr - start);
start = AlignNewSpace(kSimd128Unaligned, 3 * kPointerSize);
obj = NewSpaceAllocateAligned(kPointerSize, kSimd128Unaligned);
CHECK(IsAddressAligned(obj->address(), kSimd128Alignment, kPointerSize));
// There is a filler object before the object.
filler = HeapObject::FromAddress(start);
CHECK(obj != filler && filler->IsFiller() &&
filler->Size() == kPointerSize);
CHECK_EQ(kPointerSize + kPointerSize, *top_addr - start);
}
}
@ -2061,83 +2011,41 @@ TEST(TestAlignedOverAllocation) {
const intptr_t double_misalignment = kDoubleSize - kPointerSize;
Address start;
HeapObject* obj;
HeapObject* filler1;
HeapObject* filler2;
HeapObject* filler;
if (double_misalignment) {
start = AlignOldSpace(kDoubleAligned, 0);
obj = OldSpaceAllocateAligned(kPointerSize, kDoubleAligned);
// The object is aligned, and a filler object is created after.
CHECK(IsAddressAligned(obj->address(), kDoubleAlignment));
filler1 = HeapObject::FromAddress(start + kPointerSize);
CHECK(obj != filler1 && filler1->IsFiller() &&
filler1->Size() == kPointerSize);
filler = HeapObject::FromAddress(start + kPointerSize);
CHECK(obj != filler && filler->IsFiller() &&
filler->Size() == kPointerSize);
// Try the opposite alignment case.
start = AlignOldSpace(kDoubleAligned, kPointerSize);
obj = OldSpaceAllocateAligned(kPointerSize, kDoubleAligned);
CHECK(IsAddressAligned(obj->address(), kDoubleAlignment));
filler1 = HeapObject::FromAddress(start);
CHECK(obj != filler1);
CHECK(filler1->IsFiller());
CHECK(filler1->Size() == kPointerSize);
CHECK(obj != filler1 && filler1->IsFiller() &&
filler1->Size() == kPointerSize);
filler = HeapObject::FromAddress(start);
CHECK(obj != filler);
CHECK(filler->IsFiller());
CHECK(filler->Size() == kPointerSize);
CHECK(obj != filler && filler->IsFiller() &&
filler->Size() == kPointerSize);
// Similarly for kDoubleUnaligned.
start = AlignOldSpace(kDoubleUnaligned, 0);
obj = OldSpaceAllocateAligned(kPointerSize, kDoubleUnaligned);
// The object is aligned, and a filler object is created after.
CHECK(IsAddressAligned(obj->address(), kDoubleAlignment, kPointerSize));
filler1 = HeapObject::FromAddress(start + kPointerSize);
CHECK(obj != filler1 && filler1->IsFiller() &&
filler1->Size() == kPointerSize);
filler = HeapObject::FromAddress(start + kPointerSize);
CHECK(obj != filler && filler->IsFiller() &&
filler->Size() == kPointerSize);
// Try the opposite alignment case.
start = AlignOldSpace(kDoubleUnaligned, kPointerSize);
obj = OldSpaceAllocateAligned(kPointerSize, kDoubleUnaligned);
CHECK(IsAddressAligned(obj->address(), kDoubleAlignment, kPointerSize));
filler1 = HeapObject::FromAddress(start);
CHECK(obj != filler1 && filler1->IsFiller() &&
filler1->Size() == kPointerSize);
}
// Now test SIMD alignment. There are 2 or 4 possible alignments, depending
// on platform.
start = AlignOldSpace(kSimd128Unaligned, 0);
obj = OldSpaceAllocateAligned(kPointerSize, kSimd128Unaligned);
CHECK(IsAddressAligned(obj->address(), kSimd128Alignment, kPointerSize));
// There is a filler object after the object.
filler1 = HeapObject::FromAddress(start + kPointerSize);
CHECK(obj != filler1 && filler1->IsFiller() &&
filler1->Size() == kSimd128Size - kPointerSize);
start = AlignOldSpace(kSimd128Unaligned, kPointerSize);
obj = OldSpaceAllocateAligned(kPointerSize, kSimd128Unaligned);
CHECK(IsAddressAligned(obj->address(), kSimd128Alignment, kPointerSize));
// There is a filler object before the object.
filler1 = HeapObject::FromAddress(start);
CHECK(obj != filler1 && filler1->IsFiller() &&
filler1->Size() == kSimd128Size - kPointerSize);
if (double_misalignment) {
// Test the 2 other alignments possible on 32 bit platforms.
start = AlignOldSpace(kSimd128Unaligned, 2 * kPointerSize);
obj = OldSpaceAllocateAligned(kPointerSize, kSimd128Unaligned);
CHECK(IsAddressAligned(obj->address(), kSimd128Alignment, kPointerSize));
// There are filler objects before and after the object.
filler1 = HeapObject::FromAddress(start);
CHECK(obj != filler1 && filler1->IsFiller() &&
filler1->Size() == 2 * kPointerSize);
filler2 = HeapObject::FromAddress(start + 3 * kPointerSize);
CHECK(obj != filler2 && filler2->IsFiller() &&
filler2->Size() == kPointerSize);
start = AlignOldSpace(kSimd128Unaligned, 3 * kPointerSize);
obj = OldSpaceAllocateAligned(kPointerSize, kSimd128Unaligned);
CHECK(IsAddressAligned(obj->address(), kSimd128Alignment, kPointerSize));
// There are filler objects before and after the object.
filler1 = HeapObject::FromAddress(start);
CHECK(obj != filler1 && filler1->IsFiller() &&
filler1->Size() == kPointerSize);
filler2 = HeapObject::FromAddress(start + 2 * kPointerSize);
CHECK(obj != filler2 && filler2->IsFiller() &&
filler2->Size() == 2 * kPointerSize);
filler = HeapObject::FromAddress(start);
CHECK(obj != filler && filler->IsFiller() &&
filler->Size() == kPointerSize);
}
}