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[kernel] Change dill representation of doubles
Previously doubles was saved as strings in the string table, with a DoubleLiteral holding a StringReference. This can cause overhead in both computation time (converting the double to and from string) as well as size (e.g. a single usage of the previously unused double 1000000.42 would use (at least) * 10 bytes for the characters * 1 byte for the size * 1 byte for the reference to the string whereas saving it as a double would simply save the 8 bytes. On the other hand the string table doesn't contain duplicates so many usages of the same double will use more space. The SDK dill file size decreases slightly (< 1 KB). On a Dart file with 1M different doubles (0.42, 1.42, ..., 999999.42) added to a list: Before: compile and write via fasta (non-strong-mode): 0:12.18 Reading (via dart, eager): 2500-2600 ms Writing (to null sink) (after reading): 1600-1800 ms Output dill file (via fasta compile): ~62 MB After: compile and write via fasta (non-strong-mode): 0:11.76 Reading (via dart, eager): 2050-2350 ms Writing (to null sink) (after reading): 400-550 ms Output dill file (via fasta compile): ~54 MB Running the dill file is ~the same time, but "Maximum resident set size (kbytes)" (from /usr/bin/time -v) decreases with ~4%. On the other side, if it's 1M of the same doubles (0.42), while compiling is ~the same speed, the output dill goes from 43MB to 50MB. Surprisingly the "Maximum resident set size (kbytes)" still decreases though (~3%). Running flutter test in flutter/packages/flutter: Before: ``` 02:33 +2425 ~18: All tests passed! 02:28 +2425 ~18: All tests passed! 02:28 +2425 ~18: All tests passed! ``` After: ``` 02:12 +2425 ~18: All tests passed! 02:11 +2425 ~18: All tests passed! 02:12 +2425 ~18: All tests passed! ``` So that's -12.0267% +/- 3.15253% File size of a dill file of an arbitrary test using flutter is reduced by ~44 KB (~0.3%). Change-Id: I64151376cde1dae6f0d02b3d96991bc432a994ae Reviewed-on: https://dart-review.googlesource.com/41660 Commit-Queue: Jens Johansen <jensj@google.com> Reviewed-by: Kevin Millikin <kmillikin@google.com> Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
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@ -42,6 +42,8 @@ type UInt30 extends UInt {
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type UInt32 = big endian 32-bit unsigned integer
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type Double = Double-precision floating-point number.
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type List<T> {
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UInt length;
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T[length] items;
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@ -712,7 +714,7 @@ type BigIntLiteral extends Expression {
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type DoubleLiteral extends Expression {
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Byte tag = 40;
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StringReference valueString;
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Double value;
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}
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type TrueLiteral extends Expression {
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@ -875,7 +877,7 @@ type IntConstant extends Constant {
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type DoubleConstant extends Constant {
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Byte tag = 3;
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StringReference value;
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Double value;
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}
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type StringConstant extends Constant {
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@ -97,6 +97,22 @@ class BinaryBuilder {
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readByte();
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}
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final Float64List _doubleBuffer = new Float64List(1);
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Uint8List _doubleBufferUint8;
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double readDouble() {
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_doubleBufferUint8 ??= _doubleBuffer.buffer.asUint8List();
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_doubleBufferUint8[0] = readByte();
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_doubleBufferUint8[1] = readByte();
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_doubleBufferUint8[2] = readByte();
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_doubleBufferUint8[3] = readByte();
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_doubleBufferUint8[4] = readByte();
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_doubleBufferUint8[5] = readByte();
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_doubleBufferUint8[6] = readByte();
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_doubleBufferUint8[7] = readByte();
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return _doubleBuffer[0];
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}
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List<int> readByteList() {
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List<int> bytes = new Uint8List(readUInt());
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bytes.setRange(0, bytes.length, _bytes, _byteOffset);
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@ -174,7 +190,7 @@ class BinaryBuilder {
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case ConstantTag.IntConstant:
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return new IntConstant((readExpression() as IntLiteral).value);
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case ConstantTag.DoubleConstant:
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return new DoubleConstant(double.parse(readStringReference()));
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return new DoubleConstant(readDouble());
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case ConstantTag.StringConstant:
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return new StringConstant(readStringReference());
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case ConstantTag.MapConstant:
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@ -1337,7 +1353,7 @@ class BinaryBuilder {
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case Tag.BigIntLiteral:
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return new IntLiteral(int.parse(readStringReference()));
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case Tag.DoubleLiteral:
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return new DoubleLiteral(double.parse(readStringReference()));
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return new DoubleLiteral(readDouble());
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case Tag.TrueLiteral:
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return new BoolLiteral(true);
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case Tag.FalseLiteral:
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@ -147,7 +147,7 @@ class BinaryPrinter implements Visitor<void>, BinarySink {
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writeInteger(constant.value);
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} else if (constant is DoubleConstant) {
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writeByte(ConstantTag.DoubleConstant);
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writeStringReference('${constant.value}');
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writeDouble(constant.value);
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} else if (constant is StringConstant) {
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writeByte(ConstantTag.StringConstant);
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writeStringReference(constant.value);
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@ -1240,13 +1240,12 @@ class BinaryPrinter implements Visitor<void>, BinarySink {
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@override
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void visitDoubleLiteral(DoubleLiteral node) {
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writeByte(Tag.DoubleLiteral);
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writeDouble(node.value);
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}
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writeDouble(double value) {
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// TODO: Pick a better format for double literals.
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writeByte(Tag.DoubleLiteral);
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writeStringReference('$value');
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_sink.addDouble(value);
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}
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@override
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@ -2193,8 +2192,20 @@ class BufferedSink {
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int length = 0;
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int flushedLength = 0;
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Float64List _doubleBuffer = new Float64List(1);
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Uint8List _doubleBufferUint8;
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BufferedSink(this._sink);
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void addDouble(double d) {
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_doubleBufferUint8 ??= _doubleBuffer.buffer.asUint8List();
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_doubleBuffer[0] = d;
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addByte4(_doubleBufferUint8[0], _doubleBufferUint8[1],
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_doubleBufferUint8[2], _doubleBufferUint8[3]);
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addByte4(_doubleBufferUint8[4], _doubleBufferUint8[5],
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_doubleBufferUint8[6], _doubleBufferUint8[7]);
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}
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void addByte(int byte) {
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_buffer[length++] = byte;
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if (length == SIZE) {
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@ -135,7 +135,7 @@ class Tag {
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/// Internal version of kernel binary format.
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/// Bump it when making incompatible changes in kernel binaries.
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/// Keep in sync with runtime/vm/kernel_binary.h.
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static const int BinaryFormatVersion = 4;
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static const int BinaryFormatVersion = 5;
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}
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abstract class ConstantTag {
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@ -1552,7 +1552,7 @@ void StreamingScopeBuilder::VisitExpression() {
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builder_->ReadUInt(); // read value.
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return;
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case kDoubleLiteral:
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builder_->SkipStringReference(); // read index into string table.
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builder_->ReadDouble(); // read value.
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return;
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case kTrueLiteral:
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return;
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@ -3546,8 +3546,7 @@ void StreamingConstantEvaluator::EvaluateIntLiteral(bool is_negative) {
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}
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void StreamingConstantEvaluator::EvaluateDoubleLiteral() {
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result_ = Double::New(H.DartString(builder_->ReadStringReference()),
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Heap::kOld); // read string reference.
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result_ = Double::New(builder_->ReadDouble(), Heap::kOld); // read value.
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result_ = H.Canonicalize(result_);
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}
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@ -6027,6 +6026,10 @@ uint32_t KernelReaderHelper::PeekUInt() {
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return reader_.ReadUInt();
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}
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double KernelReaderHelper::ReadDouble() {
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return reader_.ReadDouble();
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}
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uint32_t KernelReaderHelper::PeekListLength() {
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AlternativeReadingScope alt(&reader_);
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return reader_.ReadListLength();
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@ -6494,7 +6497,7 @@ void KernelReaderHelper::SkipExpression() {
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ReadUInt(); // read value.
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return;
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case kDoubleLiteral:
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SkipStringReference(); // read index into string table.
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ReadDouble(); // read value.
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return;
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case kTrueLiteral:
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return;
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@ -8987,8 +8990,7 @@ Fragment StreamingFlowGraphBuilder::BuildDoubleLiteral(
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if (position != NULL) *position = TokenPosition::kNoSource;
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Double& constant = Double::ZoneHandle(
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Z, Double::NewCanonical(
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H.DartString(ReadStringReference()))); // read string reference.
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Z, Double::NewCanonical(ReadDouble())); // read double.
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return Constant(constant);
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}
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@ -10822,8 +10824,7 @@ const Array& ConstantHelper::ReadConstantTable() {
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break;
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}
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case kDoubleConstant: {
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temp_instance_ = Double::New(
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H.DartString(builder_.ReadStringReference()), Heap::kOld);
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temp_instance_ = Double::New(builder_.ReadDouble(), Heap::kOld);
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temp_instance_ = H.Canonicalize(temp_instance_);
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break;
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}
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@ -1049,6 +1049,7 @@ class KernelReaderHelper {
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uint32_t ReadUInt();
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uint32_t ReadUInt32();
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uint32_t PeekUInt();
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double ReadDouble();
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uint32_t PeekListLength();
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StringIndex ReadStringReference();
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NameIndex ReadCanonicalNameReference();
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@ -19,7 +19,7 @@ namespace kernel {
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// Keep in sync with package:kernel/lib/binary/tag.dart.
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static const uint32_t kMagicProgramFile = 0x90ABCDEFu;
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static const uint32_t kBinaryFormatVersion = 4;
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static const uint32_t kBinaryFormatVersion = 5;
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// Keep in sync with package:kernel/lib/binary/tag.dart
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#define KERNEL_TAG_LIST(V) \
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return value;
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}
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double ReadDouble() {
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ASSERT((size_ >= 8) && (offset_ >= 0) && (offset_ <= size_ - 8));
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double value = ReadUnaligned(
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reinterpret_cast<const double*>(&this->buffer()[offset_]));
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offset_ += 8;
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return value;
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}
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uint32_t ReadUInt() {
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ASSERT((size_ >= 1) && (offset_ >= 0) && (offset_ <= size_ - 1));
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@ -82,8 +82,7 @@ class SimpleExpressionConverter {
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return true;
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case kDoubleLiteral:
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simple_value_ = &Double::ZoneHandle(
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Z, Double::New(H.DartString(builder_->ReadStringReference()),
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Heap::kOld)); // read string reference.
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Z, Double::New(builder_->ReadDouble(), Heap::kOld)); // read value.
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*simple_value_ = H.Canonicalize(*simple_value_);
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return true;
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case kTrueLiteral:
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