private static void WriteFakeILWithBranches(BlobBuilder builder, ControlFlowBuilder branchBuilder, int size)
{
Assert.Equal(0, builder.Count);
const byte filling = 0x01;
int ilOffset = 0;
foreach (var branch in branchBuilder.Branches)
{
builder.WriteBytes(filling, branch.ILOffset - ilOffset);
Assert.Equal(branch.ILOffset, builder.Count);
builder.WriteByte((byte)branch.OpCode);
int operandSize = branch.OpCode.GetBranchOperandSize();
if (operandSize == 1)
{
builder.WriteSByte(-1);
}
else
{
builder.WriteInt32(-1);
}
ilOffset = branch.ILOffset + sizeof(byte) + operandSize;
}
builder.WriteBytes(filling, size - ilOffset);
Assert.Equal(size, builder.Count);
}
private static void WriteFakeILWithBranches(BlobBuilder builder, ControlFlowBuilder branchBuilder, int size)
{
Assert.Equal(0, builder.Count);
const byte filling = 0x01;
int ilOffset = 0;
foreach (var branch in branchBuilder.Branches)
{
builder.WriteBytes(filling, branch.ILOffset - ilOffset);
Assert.Equal(branch.ILOffset, builder.Count);
builder.WriteByte((byte)branch.OpCode);
int operandSize = branch.OpCode.GetBranchOperandSize();
if (operandSize == 1)
{
builder.WriteSByte(-1);
}
else
{
builder.WriteInt32(-1);
}
ilOffset = branch.ILOffset + sizeof(byte) + operandSize;
}
builder.WriteBytes(filling, size - ilOffset);
Assert.Equal(size, builder.Count);
}
public void Serialize(BlobBuilder writer)
{
switch (this.Discriminator)
{
case ConstantValueTypeDiscriminator.Boolean:
writer.WriteBoolean(this.BooleanValue);
break;
case ConstantValueTypeDiscriminator.SByte:
writer.WriteSByte(this.SByteValue);
break;
case ConstantValueTypeDiscriminator.Byte:
writer.WriteByte(this.ByteValue);
break;
case ConstantValueTypeDiscriminator.Char:
case ConstantValueTypeDiscriminator.Int16:
writer.WriteInt16(this.Int16Value);
break;
case ConstantValueTypeDiscriminator.UInt16:
writer.WriteUInt16(this.UInt16Value);
break;
case ConstantValueTypeDiscriminator.Single:
writer.WriteSingle(this.SingleValue);
break;
case ConstantValueTypeDiscriminator.Int32:
writer.WriteInt32(this.Int32Value);
break;
case ConstantValueTypeDiscriminator.UInt32:
writer.WriteUInt32(this.UInt32Value);
break;
case ConstantValueTypeDiscriminator.Double:
writer.WriteDouble(this.DoubleValue);
break;
case ConstantValueTypeDiscriminator.Int64:
writer.WriteInt64(this.Int64Value);
break;
case ConstantValueTypeDiscriminator.UInt64:
writer.WriteUInt64(this.UInt64Value);
break;
default:
throw ExceptionUtilities.UnexpectedValue(this.Discriminator);
}
}
public void WritePrimitive()
{
var writer = new BlobBuilder(17);
writer.WriteUInt32(0x11223344);
writer.WriteUInt16(0x5566);
writer.WriteByte(0x77);
writer.WriteUInt64(0x8899aabbccddeeff);
writer.WriteInt32(-1);
writer.WriteInt16(-2);
writer.WriteSByte(-3);
writer.WriteBoolean(true);
writer.WriteBoolean(false);
writer.WriteInt64(unchecked ((long)0xfedcba0987654321));
writer.WriteDateTime(new DateTime(0x1112223334445556));
writer.WriteDecimal(102030405060.70m);
writer.WriteDouble(double.NaN);
writer.WriteSingle(float.NegativeInfinity);
var guid = new Guid("01020304-0506-0708-090A-0B0C0D0E0F10");
writer.WriteBytes(guid.ToByteArray());
writer.WriteGuid(guid);
AssertEx.Equal(new byte[]
{
0x44, 0x33, 0x22, 0x11,
0x66, 0x55,
0x77,
0xff, 0xee, 0xdd, 0xcc, 0xbb, 0xaa, 0x99, 0x88,
0xff, 0xff, 0xff, 0xff,
0xfe, 0xff,
0xfd,
0x01,
0x00,
0x21, 0x43, 0x65, 0x87, 0x09, 0xBA, 0xDC, 0xFE,
0x56, 0x55, 0x44, 0x34, 0x33, 0x22, 0x12, 0x11,
0x02, 0xD6, 0xE0, 0x9A, 0x94, 0x47, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF8, 0xFF,
0x00, 0x00, 0x80, 0xFF,
0x04, 0x03, 0x02, 0x01, 0x06, 0x05, 0x08, 0x07, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10,
0x04, 0x03, 0x02, 0x01, 0x06, 0x05, 0x08, 0x07, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10
}, writer.ToArray());
}
internal void FixupBranches(BlobBuilder srcBuilder, BlobBuilder dstBuilder)
{
int srcOffset = 0;
var branch = _branches[0];
int branchIndex = 0;
int blobOffset = 0;
foreach (Blob blob in srcBuilder.GetBlobs())
{
Debug.Assert(blobOffset == 0 || blobOffset == 1 && blob.Buffer[blobOffset - 1] == 0xff);
while (true)
{
// copy bytes preceding the next branch, or till the end of the blob:
int chunkSize = Math.Min(branch.ILOffset - srcOffset, blob.Length - blobOffset);
dstBuilder.WriteBytes(blob.Buffer, blobOffset, chunkSize);
srcOffset += chunkSize;
blobOffset += chunkSize;
// there is no branch left in the blob:
if (blobOffset == blob.Length)
{
blobOffset = 0;
break;
}
Debug.Assert(blob.Buffer[blobOffset] == branch.ShortOpCode && (blobOffset + 1 == blob.Length || blob.Buffer[blobOffset + 1] == 0xff));
srcOffset += sizeof(byte) + sizeof(sbyte);
// write actual branch instruction:
int branchDistance;
if (branch.IsShortBranchDistance(_labels, out branchDistance))
{
dstBuilder.WriteByte(branch.ShortOpCode);
dstBuilder.WriteSByte((sbyte)branchDistance);
}
else
{
dstBuilder.WriteByte((byte)((ILOpCode)branch.ShortOpCode).GetLongBranch());
dstBuilder.WriteInt32(branchDistance);
}
// next branch:
branchIndex++;
if (branchIndex == _branches.Count)
{
branch = new BranchInfo(int.MaxValue, default(LabelHandle), 0);
}
else
{
branch = _branches[branchIndex];
}
// the branch starts at the very end and its operand is in the next blob:
if (blobOffset == blob.Length - 1)
{
blobOffset = 1;
break;
}
// skip fake branch instruction:
blobOffset += sizeof(byte) + sizeof(sbyte);
}
}
}
/// <exception cref="InvalidOperationException" />
internal void CopyCodeAndFixupBranches(BlobBuilder srcBuilder, BlobBuilder dstBuilder)
{
var branch = _branches[0];
int branchIndex = 0;
// offset within the source builder
int srcOffset = 0;
// current offset within the current source blob
int srcBlobOffset = 0;
foreach (Blob srcBlob in srcBuilder.GetBlobs())
{
Debug.Assert(
srcBlobOffset == 0 ||
srcBlobOffset == 1 && srcBlob.Buffer[0] == 0xff ||
srcBlobOffset == 4 && srcBlob.Buffer[0] == 0xff && srcBlob.Buffer[1] == 0xff && srcBlob.Buffer[2] == 0xff && srcBlob.Buffer[3] == 0xff);
while (true)
{
// copy bytes preceding the next branch, or till the end of the blob:
int chunkSize = Math.Min(branch.ILOffset - srcOffset, srcBlob.Length - srcBlobOffset);
dstBuilder.WriteBytes(srcBlob.Buffer, srcBlobOffset, chunkSize);
srcOffset += chunkSize;
srcBlobOffset += chunkSize;
// there is no branch left in the blob:
if (srcBlobOffset == srcBlob.Length)
{
srcBlobOffset = 0;
break;
}
Debug.Assert(srcBlob.Buffer[srcBlobOffset] == (byte)branch.OpCode);
int operandSize = branch.OpCode.GetBranchOperandSize();
bool isShortInstruction = operandSize == 1;
// Note: the 4B operand is contiguous since we wrote it via BlobBuilder.WriteInt32()
Debug.Assert(
srcBlobOffset + 1 == srcBlob.Length ||
(isShortInstruction ?
srcBlob.Buffer[srcBlobOffset + 1] == 0xff :
BitConverter.ToUInt32(srcBlob.Buffer, srcBlobOffset + 1) == 0xffffffff));
// write branch opcode:
dstBuilder.WriteByte(srcBlob.Buffer[srcBlobOffset]);
// write branch operand:
int branchDistance;
bool isShortDistance = branch.IsShortBranchDistance(_labels, out branchDistance);
if (isShortInstruction && !isShortDistance)
{
// We could potentially implement algortihm that automatically fixes up the branch instructions as well to accomodate bigger distances,
// however an optimal algorithm would be rather complex (something like: calculate topological ordering of crossing branch instructions
// and then use fixed point to eliminate cycles). If the caller doesn't care about optimal IL size they can use long branches whenever the
// distance is unknown upfront. If they do they probably already implement more sophisticad algorithm for IL layout optimization already.
throw new InvalidOperationException(SR.Format(SR.DistanceBetweenInstructionAndLabelTooBig, branch.OpCode, srcOffset, branchDistance));
}
if (isShortInstruction)
{
dstBuilder.WriteSByte((sbyte)branchDistance);
}
else
{
dstBuilder.WriteInt32(branchDistance);
}
srcOffset += sizeof(byte) + operandSize;
// next branch:
branchIndex++;
if (branchIndex == _branches.Count)
{
branch = new BranchInfo(int.MaxValue, default(LabelHandle), 0);
}
else
{
branch = _branches[branchIndex];
}
// the branch starts at the very end and its operand is in the next blob:
if (srcBlobOffset == srcBlob.Length - 1)
{
srcBlobOffset = operandSize;
break;
}
// skip fake branch instruction:
srcBlobOffset += sizeof(byte) + operandSize;
}
}
}
/// <exception cref="InvalidOperationException" />
internal void CopyCodeAndFixupBranches(BlobBuilder srcBuilder, BlobBuilder dstBuilder)
{
var branch = _branches[0];
int branchIndex = 0;
// offset within the source builder
int srcOffset = 0;
// current offset within the current source blob
int srcBlobOffset = 0;
foreach (Blob srcBlob in srcBuilder.GetBlobs())
{
Debug.Assert(
srcBlobOffset == 0 ||
srcBlobOffset == 1 && srcBlob.Buffer[0] == 0xff ||
srcBlobOffset == 4 && srcBlob.Buffer[0] == 0xff && srcBlob.Buffer[1] == 0xff && srcBlob.Buffer[2] == 0xff && srcBlob.Buffer[3] == 0xff);
while (true)
{
// copy bytes preceding the next branch, or till the end of the blob:
int chunkSize = Math.Min(branch.ILOffset - srcOffset, srcBlob.Length - srcBlobOffset);
dstBuilder.WriteBytes(srcBlob.Buffer, srcBlobOffset, chunkSize);
srcOffset += chunkSize;
srcBlobOffset += chunkSize;
// there is no branch left in the blob:
if (srcBlobOffset == srcBlob.Length)
{
srcBlobOffset = 0;
break;
}
Debug.Assert(srcBlob.Buffer[srcBlobOffset] == (byte)branch.OpCode);
int operandSize = branch.OpCode.GetBranchOperandSize();
bool isShortInstruction = operandSize == 1;
// Note: the 4B operand is contiguous since we wrote it via BlobBuilder.WriteInt32()
Debug.Assert(
srcBlobOffset + 1 == srcBlob.Length ||
(isShortInstruction ?
srcBlob.Buffer[srcBlobOffset + 1] == 0xff :
BitConverter.ToUInt32(srcBlob.Buffer, srcBlobOffset + 1) == 0xffffffff));
// write branch opcode:
dstBuilder.WriteByte(srcBlob.Buffer[srcBlobOffset]);
int branchDistance = branch.GetBranchDistance(_labels, branch.OpCode, srcOffset, isShortInstruction);
// write branch operand:
if (isShortInstruction)
{
dstBuilder.WriteSByte((sbyte)branchDistance);
}
else
{
dstBuilder.WriteInt32(branchDistance);
}
srcOffset += sizeof(byte) + operandSize;
// next branch:
branchIndex++;
if (branchIndex == _branches.Count)
{
branch = new BranchInfo(int.MaxValue, label: default, opCode: default);
public void WritePrimitive()
{
var writer = new BlobBuilder(17);
writer.WriteUInt32(0x11223344);
writer.WriteUInt16(0x5566);
writer.WriteByte(0x77);
writer.WriteUInt64(0x8899aabbccddeeff);
writer.WriteInt32(-1);
writer.WriteInt16(-2);
writer.WriteSByte(-3);
writer.WriteBoolean(true);
writer.WriteBoolean(false);
writer.WriteInt64(unchecked((long)0xfedcba0987654321));
writer.WriteDateTime(new DateTime(0x1112223334445556));
writer.WriteDecimal(102030405060.70m);
writer.WriteDouble(double.NaN);
writer.WriteSingle(float.NegativeInfinity);
var guid = new Guid("01020304-0506-0708-090A-0B0C0D0E0F10");
writer.WriteBytes(guid.ToByteArray());
writer.WriteGuid(guid);
AssertEx.Equal(new byte[]
{
0x44, 0x33, 0x22, 0x11,
0x66, 0x55,
0x77,
0xff, 0xee, 0xdd, 0xcc, 0xbb, 0xaa, 0x99, 0x88,
0xff, 0xff, 0xff, 0xff,
0xfe, 0xff,
0xfd,
0x01,
0x00,
0x21, 0x43, 0x65, 0x87, 0x09, 0xBA, 0xDC, 0xFE,
0x56, 0x55, 0x44, 0x34, 0x33, 0x22, 0x12, 0x11,
0x02, 0xD6, 0xE0, 0x9A, 0x94, 0x47, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF8, 0xFF,
0x00, 0x00, 0x80, 0xFF,
0x04, 0x03, 0x02, 0x01, 0x06, 0x05, 0x08, 0x07, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10,
0x04, 0x03, 0x02, 0x01, 0x06, 0x05, 0x08, 0x07, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10
}, writer.ToArray());
}
internal void FixupBranches(BlobBuilder srcBuilder, BlobBuilder dstBuilder)
{
int srcOffset = 0;
var branch = _branches[0];
int branchIndex = 0;
int blobOffset = 0;
foreach (Blob blob in srcBuilder.GetBlobs())
{
Debug.Assert(blobOffset == 0 || blobOffset == 1 && blob.Buffer[blobOffset - 1] == 0xff);
while (true)
{
// copy bytes preceding the next branch, or till the end of the blob:
int chunkSize = Math.Min(branch.ILOffset - srcOffset, blob.Length - blobOffset);
dstBuilder.WriteBytes(blob.Buffer, blobOffset, chunkSize);
srcOffset += chunkSize;
blobOffset += chunkSize;
// there is no branch left in the blob:
if (blobOffset == blob.Length)
{
blobOffset = 0;
break;
}
Debug.Assert(blob.Buffer[blobOffset] == branch.ShortOpCode && (blobOffset + 1 == blob.Length || blob.Buffer[blobOffset + 1] == 0xff));
srcOffset += sizeof(byte) + sizeof(sbyte);
// write actual branch instruction:
int branchDistance;
if (branch.IsShortBranchDistance(_labels, out branchDistance))
{
dstBuilder.WriteByte(branch.ShortOpCode);
dstBuilder.WriteSByte((sbyte)branchDistance);
}
else
{
dstBuilder.WriteByte((byte)((ILOpCode)branch.ShortOpCode).GetLongBranch());
dstBuilder.WriteInt32(branchDistance);
}
// next branch:
branchIndex++;
if (branchIndex == _branches.Count)
{
branch = new BranchInfo(int.MaxValue, default(LabelHandle), 0);
}
else
{
branch = _branches[branchIndex];
}
// the branch starts at the very end and its operand is in the next blob:
if (blobOffset == blob.Length - 1)
{
blobOffset = 1;
break;
}
// skip fake branch instruction:
blobOffset += sizeof(byte) + sizeof(sbyte);
}
}
}
internal static void WriteConstant(BlobBuilder writer, object value)
{
if (value == null)
{
// The encoding of Type for the nullref value for FieldInit is ELEMENT_TYPE_CLASS with a Value of a 32-bit.
writer.WriteUInt32(0);
return;
}
var type = value.GetType();
if (type.GetTypeInfo().IsEnum)
{
type = Enum.GetUnderlyingType(type);
}
if (type == typeof(bool))
{
writer.WriteBoolean((bool)value);
}
else if (type == typeof(int))
{
writer.WriteInt32((int)value);
}
else if (type == typeof(string))
{
writer.WriteUTF16((string)value);
}
else if (type == typeof(byte))
{
writer.WriteByte((byte)value);
}
else if (type == typeof(char))
{
writer.WriteUInt16((char)value);
}
else if (type == typeof(double))
{
writer.WriteDouble((double)value);
}
else if (type == typeof(short))
{
writer.WriteInt16((short)value);
}
else if (type == typeof(long))
{
writer.WriteInt64((long)value);
}
else if (type == typeof(sbyte))
{
writer.WriteSByte((sbyte)value);
}
else if (type == typeof(float))
{
writer.WriteSingle((float)value);
}
else if (type == typeof(ushort))
{
writer.WriteUInt16((ushort)value);
}
else if (type == typeof(uint))
{
writer.WriteUInt32((uint)value);
}
else if (type == typeof(ulong))
{
writer.WriteUInt64((ulong)value);
}
else
{
// TODO: message
throw new ArgumentException();
}
}
public static void Write(
BlobBuilder writer,
IReadOnlyList <Instruction> il,
Func <string, StringHandle> getString,
IReadOnlyDictionary <Guid, EntityHandle> typeHandles,
IReadOnlyDictionary <ConstructorInfo, MemberReferenceHandle> ctorRefHandles,
IReadOnlyDictionary <FieldInfo, FieldDefinitionHandle> fieldHandles,
IReadOnlyDictionary <MethodInfo, MethodDefinitionHandle> methodHandles)
{
var targetOffsets = new ArrayMapper <int>();
//var offsetIndex = new Dictionary<int, int>();
for (var i = 0; i < il.Count; i++)
{
//offsetIndex.Add(il[i].Offset, i);
var opCode = il[i].OpCode;
opCode.WriteOpCode(writer.WriteByte);
switch (opCode.OperandType)
{
case OperandType.InlineNone:
break;
case OperandType.InlineSwitch:
var branches = (int[])il[i].Operand;
writer.WriteInt32(branches.Length);
for (var k = 0; k < branches.Length; k++)
{
var branchOffset = branches[k];
writer.WriteInt32(targetOffsets.Add(
branchOffset + il[i].Offset + opCode.Size + 4 * (branches.Length + 1)));
}
break;
case OperandType.ShortInlineBrTarget:
var offset8 = (sbyte)il[i].Operand;
// offset convention in IL: zero is at next instruction
writer.WriteSByte((sbyte)targetOffsets.Add(offset8 + il[i].Offset + opCode.Size + 1));
break;
case OperandType.InlineBrTarget:
var offset32 = (int)il[i].Operand;
// offset convention in IL: zero is at next instruction
writer.WriteInt32(targetOffsets.Add(offset32 + il[i].Offset + opCode.Size + 4));
break;
case OperandType.ShortInlineI:
if (opCode == OpCodes.Ldc_I4_S)
{
writer.WriteSByte((sbyte)il[i].Operand);
}
else
{
writer.WriteByte((byte)il[i].Operand);
}
break;
case OperandType.InlineI:
writer.WriteInt32((int)il[i].Operand);
break;
case OperandType.ShortInlineR:
writer.WriteSingle((float)il[i].Operand);
break;
case OperandType.InlineR:
writer.WriteDouble((double)il[i].Operand);
break;
case OperandType.InlineI8:
writer.WriteInt64((long)il[i].Operand);
break;
case OperandType.InlineSig:
writer.WriteBytes((byte[])il[i].Operand);
break;
case OperandType.InlineString:
writer.WriteInt32(MetadataTokens.GetToken(getString((string)il[i].Operand)));
break;
case OperandType.InlineType:
case OperandType.InlineTok:
case OperandType.InlineMethod:
case OperandType.InlineField:
switch (il[i].Operand)
{
case Type type:
writer.WriteInt32(MetadataTokens.GetToken(typeHandles[type.GUID]));
break;
case ConstructorInfo constructorInfo:
writer.WriteInt32(MetadataTokens.GetToken(ctorRefHandles[constructorInfo]));
break;
case FieldInfo fieldInfo:
writer.WriteInt32(MetadataTokens.GetToken(fieldHandles[fieldInfo]));
break;
case MethodInfo methodInfo:
writer.WriteInt32(MetadataTokens.GetToken(methodHandles[methodInfo]));
break;
default:
throw new NotSupportedException();
}
break;
case OperandType.ShortInlineVar:
var bLocalVariableInfo = il[i].Operand as LocalVariableInfo;
var bParameterInfo = il[i].Operand as ParameterInfo;
if (bLocalVariableInfo != null)
{
writer.WriteByte((byte)bLocalVariableInfo.LocalIndex);
}
else if (bParameterInfo != null)
{
writer.WriteByte((byte)bParameterInfo.Position);
}
else
{
throw new NotSupportedException();
}
break;
case OperandType.InlineVar:
var sLocalVariableInfo = il[i].Operand as LocalVariableInfo;
var sParameterInfo = il[i].Operand as ParameterInfo;
if (sLocalVariableInfo != null)
{
writer.WriteUInt16((ushort)sLocalVariableInfo.LocalIndex);
}
else if (sParameterInfo != null)
{
writer.WriteUInt16((ushort)sParameterInfo.Position);
}
else
{
throw new NotSupportedException();
}
break;
default:
throw new NotSupportedException();
}
}
}
internal static void WriteConstant(BlobBuilder writer, object value)
{
if (value == null)
{
// The encoding of Type for the nullref value for FieldInit is ELEMENT_TYPE_CLASS with a Value of a 32-bit.
writer.WriteUInt32(0);
return;
}
var type = value.GetType();
if (type.GetTypeInfo().IsEnum)
{
type = Enum.GetUnderlyingType(type);
}
if (type == typeof(bool))
{
writer.WriteBoolean((bool)value);
}
else if (type == typeof(int))
{
writer.WriteInt32((int)value);
}
else if (type == typeof(string))
{
writer.WriteUTF16((string)value);
}
else if (type == typeof(byte))
{
writer.WriteByte((byte)value);
}
else if (type == typeof(char))
{
writer.WriteUInt16((char)value);
}
else if (type == typeof(double))
{
writer.WriteDouble((double)value);
}
else if (type == typeof(short))
{
writer.WriteInt16((short)value);
}
else if (type == typeof(long))
{
writer.WriteInt64((long)value);
}
else if (type == typeof(sbyte))
{
writer.WriteSByte((sbyte)value);
}
else if (type == typeof(float))
{
writer.WriteSingle((float)value);
}
else if (type == typeof(ushort))
{
writer.WriteUInt16((ushort)value);
}
else if (type == typeof(uint))
{
writer.WriteUInt32((uint)value);
}
else if (type == typeof(ulong))
{
writer.WriteUInt64((ulong)value);
}
else
{
// TODO: message
throw new ArgumentException();
}
}
/// <exception cref="InvalidOperationException" />
internal void CopyCodeAndFixupBranches(BlobBuilder srcBuilder, BlobBuilder dstBuilder)
{
var branch = _branches[0];
int branchIndex = 0;
// offset within the source builder
int srcOffset = 0;
// current offset within the current source blob
int srcBlobOffset = 0;
foreach (Blob srcBlob in srcBuilder.GetBlobs())
{
Debug.Assert(
srcBlobOffset == 0 ||
srcBlobOffset == 1 && srcBlob.Buffer[0] == 0xff ||
srcBlobOffset == 4 && srcBlob.Buffer[0] == 0xff && srcBlob.Buffer[1] == 0xff && srcBlob.Buffer[2] == 0xff && srcBlob.Buffer[3] == 0xff);
while (true)
{
// copy bytes preceding the next branch, or till the end of the blob:
int chunkSize = Math.Min(branch.ILOffset - srcOffset, srcBlob.Length - srcBlobOffset);
dstBuilder.WriteBytes(srcBlob.Buffer, srcBlobOffset, chunkSize);
srcOffset += chunkSize;
srcBlobOffset += chunkSize;
// there is no branch left in the blob:
if (srcBlobOffset == srcBlob.Length)
{
srcBlobOffset = 0;
break;
}
Debug.Assert(srcBlob.Buffer[srcBlobOffset] == (byte)branch.OpCode);
int operandSize = branch.OpCode.GetBranchOperandSize();
bool isShortInstruction = operandSize == 1;
// Note: the 4B operand is contiguous since we wrote it via BlobBuilder.WriteInt32()
Debug.Assert(
srcBlobOffset + 1 == srcBlob.Length ||
(isShortInstruction ?
srcBlob.Buffer[srcBlobOffset + 1] == 0xff :
BitConverter.ToUInt32(srcBlob.Buffer, srcBlobOffset + 1) == 0xffffffff));
// write branch opcode:
dstBuilder.WriteByte(srcBlob.Buffer[srcBlobOffset]);
// write branch operand:
int branchDistance;
bool isShortDistance = branch.IsShortBranchDistance(_labels, out branchDistance);
if (isShortInstruction && !isShortDistance)
{
// We could potentially implement algortihm that automatically fixes up the branch instructions as well to accomodate bigger distances,
// however an optimal algorithm would be rather complex (something like: calculate topological ordering of crossing branch instructions
// and then use fixed point to eliminate cycles). If the caller doesn't care about optimal IL size they can use long branches whenever the
// distance is unknown upfront. If they do they probably already implement more sophisticad algorithm for IL layout optimization already.
throw new InvalidOperationException(SR.Format(SR.DistanceBetweenInstructionAndLabelTooBig, branch.OpCode, srcOffset, branchDistance));
}
if (isShortInstruction)
{
dstBuilder.WriteSByte((sbyte)branchDistance);
}
else
{
dstBuilder.WriteInt32(branchDistance);
}
srcOffset += sizeof(byte) + operandSize;
// next branch:
branchIndex++;
if (branchIndex == _branches.Count)
{
branch = new BranchInfo(int.MaxValue, default(LabelHandle), 0);
}
else
{
branch = _branches[branchIndex];
}
// the branch starts at the very end and its operand is in the next blob:
if (srcBlobOffset == srcBlob.Length - 1)
{
srcBlobOffset = operandSize;
break;
}
// skip fake branch instruction:
srcBlobOffset += sizeof(byte) + operandSize;
}
}
}