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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Buffers.Binary;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Diagnostics.SymbolStore;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
namespace System.Reflection.Emit
{
internal class RuntimeILGenerator : ILGenerator
{
#region Const Members
private const int DefaultSize = 16;
private const int DefaultFixupArraySize = 8;
private const int DefaultLabelArraySize = 4;
private const int DefaultExceptionArraySize = 2;
#endregion
#region Internal Statics
internal static T[] EnlargeArray<T>(T[] incoming)
{
return EnlargeArray(incoming, incoming.Length * 2);
}
internal static T[] EnlargeArray<T>(T[] incoming, int requiredSize)
{
Debug.Assert(incoming != null);
T[] temp = new T[requiredSize];
Array.Copy(incoming, temp, incoming.Length);
return temp;
}
#endregion
#region Internal Data Members
private int m_length;
private byte[] m_ILStream;
private __LabelInfo[]? m_labelList;
private int m_labelCount;
private __FixupData[]? m_fixupData;
private int m_fixupCount;
private int[]? m_RelocFixupList;
private int m_RelocFixupCount;
private int m_exceptionCount;
private int m_currExcStackCount;
private __ExceptionInfo[]? m_exceptions; // This is the list of all of the exceptions in this ILStream.
private __ExceptionInfo[]? m_currExcStack; // This is the stack of exceptions which we're currently in.
internal ScopeTree m_ScopeTree; // this variable tracks all debugging scope information
internal MethodInfo m_methodBuilder;
internal int m_localCount;
internal SignatureHelper m_localSignature;
private int m_curDepth; // Current stack depth, with -1 meaning unknown.
private int m_targetDepth; // Stack depth at a target of the previous instruction (when it is branching).
private int m_maxDepth; // Running max of the stack depth.
// Adjustment to add to m_maxDepth for incorrect/invalid IL. For example, when branch instructions
// with different stack depths target the same label.
private long m_depthAdjustment;
internal int CurrExcStackCount => m_currExcStackCount;
internal __ExceptionInfo[]? CurrExcStack => m_currExcStack;
#endregion
#region Constructor
// package private constructor. This code path is used when client create
// ILGenerator through MethodBuilder.
internal RuntimeILGenerator(MethodInfo methodBuilder) : this(methodBuilder, 64)
{
}
internal RuntimeILGenerator(MethodInfo methodBuilder, int size)
{
Debug.Assert(methodBuilder != null);
Debug.Assert(methodBuilder is MethodBuilder || methodBuilder is DynamicMethod);
m_ILStream = new byte[Math.Max(size, DefaultSize)];
// initialize the scope tree
m_ScopeTree = new ScopeTree();
m_methodBuilder = methodBuilder;
// initialize local signature
RuntimeMethodBuilder? mb = m_methodBuilder as RuntimeMethodBuilder;
m_localSignature = SignatureHelper.GetLocalVarSigHelper(mb?.GetTypeBuilder().Module);
}
#endregion
#region Internal Members
internal virtual void RecordTokenFixup()
{
if (m_RelocFixupList == null)
{
m_RelocFixupList = new int[DefaultFixupArraySize];
}
else if (m_RelocFixupList.Length <= m_RelocFixupCount)
{
m_RelocFixupList = EnlargeArray(m_RelocFixupList);
}
m_RelocFixupList[m_RelocFixupCount++] = m_length;
}
internal void InternalEmit(OpCode opcode)
{
short opcodeValue = opcode.Value;
if (opcode.Size != 1)
{
BinaryPrimitives.WriteInt16BigEndian(m_ILStream.AsSpan(m_length), opcodeValue);
m_length += 2;
}
else
{
m_ILStream[m_length++] = (byte)opcodeValue;
}
UpdateStackSize(opcode, opcode.EvaluationStackDelta);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal void UpdateStackSize(OpCode opcode, int stackchange)
{
// Updates internal variables for keeping track of the stack size
// requirements for the function. stackchange specifies the amount
// by which the stacksize needs to be updated.
if (m_curDepth < 0)
{
// Current depth is "unknown". We get here when:
// * this is unreachable code.
// * the client uses explicit numeric offsets rather than Labels.
m_curDepth = 0;
}
m_curDepth += stackchange;
if (m_curDepth < 0)
{
// Stack underflow. Assume our previous depth computation was flawed.
m_depthAdjustment -= m_curDepth;
m_curDepth = 0;
}
else if (m_maxDepth < m_curDepth)
m_maxDepth = m_curDepth;
Debug.Assert(m_depthAdjustment >= 0);
Debug.Assert(m_curDepth >= 0);
// Record the stack depth at a "target" of this instruction.
m_targetDepth = m_curDepth;
// If the current instruction can't fall through, set the depth to unknown.
if (opcode.EndsUncondJmpBlk())
m_curDepth = -1;
}
private int GetMethodToken(MethodBase method, Type[]? optionalParameterTypes, bool useMethodDef)
{
return ((RuntimeModuleBuilder)m_methodBuilder.Module).GetMethodTokenInternal(method, optionalParameterTypes, useMethodDef);
}
internal SignatureHelper GetMemberRefSignature(
CallingConventions call,
Type? returnType,
Type[]? parameterTypes,
Type[]? optionalParameterTypes)
{
return ((RuntimeModuleBuilder)m_methodBuilder.Module).GetMemberRefSignature(call, returnType, parameterTypes, null, null, optionalParameterTypes, 0);
}
internal byte[]? BakeByteArray()
{
// BakeByteArray is an internal function designed to be called by MethodBuilder to do
// all of the fixups and return a new byte array representing the byte stream with labels resolved, etc.
if (m_currExcStackCount != 0)
{
throw new ArgumentException(SR.Argument_UnclosedExceptionBlock);
}
if (m_length == 0)
return null;
// Allocate space for the new array.
byte[] newBytes = new byte[m_length];
// Copy the data from the old array
Array.Copy(m_ILStream, newBytes, m_length);
// Do the fixups.
// This involves iterating over all of the labels and
// replacing them with their proper values.
for (int i = 0; i < m_fixupCount; i++)
{
__FixupData fixupData = m_fixupData![i];
int updateAddr = GetLabelPos(fixupData.m_fixupLabel) - (fixupData.m_fixupPos + fixupData.m_fixupInstSize);
// Handle single byte instructions
// Throw an exception if they're trying to store a jump in a single byte instruction that doesn't fit.
if (fixupData.m_fixupInstSize == 1)
{
// Verify that our one-byte arg will fit into a Signed Byte.
if (updateAddr < sbyte.MinValue || updateAddr > sbyte.MaxValue)
{
throw new NotSupportedException(SR.Format(SR.NotSupported_IllegalOneByteBranch, fixupData.m_fixupPos, updateAddr));
}
// Place the one-byte arg
newBytes[fixupData.m_fixupPos] = (byte)updateAddr;
}
else
{
// Place the four-byte arg
BinaryPrimitives.WriteInt32LittleEndian(newBytes.AsSpan(fixupData.m_fixupPos), updateAddr);
}
}
return newBytes;
}
internal __ExceptionInfo[]? GetExceptions()
{
if (m_currExcStackCount != 0)
{
throw new NotSupportedException(SR.Argument_UnclosedExceptionBlock);
}
if (m_exceptionCount == 0)
{
return null;
}
var temp = new __ExceptionInfo[m_exceptionCount];
Array.Copy(m_exceptions!, temp, m_exceptionCount);
SortExceptions(temp);
return temp;
}
internal void EnsureCapacity(int size)
{
// Guarantees an array capable of holding at least size elements.
if (m_length + size >= m_ILStream.Length)
{
IncreaseCapacity(size);
}
}
private void IncreaseCapacity(int size)
{
byte[] temp = new byte[Math.Max(m_ILStream.Length * 2, m_length + size)];
Array.Copy(m_ILStream, temp, m_ILStream.Length);
m_ILStream = temp;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal void PutInteger4(int value)
{
BinaryPrimitives.WriteInt32LittleEndian(m_ILStream.AsSpan(m_length), value);
m_length += 4;
}
private int GetLabelPos(Label lbl)
{
// Gets the position in the stream of a particular label.
// Verifies that the label exists and that it has been given a value.
int index = lbl.Id;
if (index < 0 || index >= m_labelCount || m_labelList is null)
throw new ArgumentException(SR.Argument_BadLabel);
int pos = m_labelList[index].m_pos;
if (pos < 0)
throw new ArgumentException(SR.Argument_BadLabelContent);
return pos;
}
private void AddFixup(Label lbl, int pos, int instSize)
{
// Notes the label, position, and instruction size of a new fixup. Expands
// all of the fixup arrays as appropriate.
if (m_fixupData == null)
{
m_fixupData = new __FixupData[DefaultFixupArraySize];
}
else if (m_fixupData.Length <= m_fixupCount)
{
m_fixupData = EnlargeArray(m_fixupData);
}
m_fixupData[m_fixupCount++] = new __FixupData
{
m_fixupPos = pos,
m_fixupLabel = lbl,
m_fixupInstSize = instSize
};
int labelIndex = lbl.Id;
if (labelIndex < 0 || labelIndex >= m_labelCount || m_labelList is null)
throw new ArgumentException(SR.Argument_BadLabel);
int depth = m_labelList[labelIndex].m_depth;
int targetDepth = m_targetDepth;
Debug.Assert(depth >= -1);
Debug.Assert(targetDepth >= -1);
if (depth < targetDepth)
{
// Either unknown depth for this label or this branch location has a larger depth than previously recorded.
// In the latter case, the IL is (likely) invalid, but we just compensate for it.
if (depth >= 0)
m_depthAdjustment += targetDepth - depth;
m_labelList[labelIndex].m_depth = targetDepth;
}
}
internal int GetMaxStackSize()
{
// Limit the computed max stack to 2^16 - 1, since the value is mod`ed by 2^16 by other code.
Debug.Assert(m_depthAdjustment >= 0);
return (int)Math.Min(ushort.MaxValue, m_maxDepth + m_depthAdjustment);
}
private static void SortExceptions(__ExceptionInfo[] exceptions)
{
// In order to call exceptions properly we have to sort them in ascending order by their end position.
// Just a cheap insertion sort. We don't expect many exceptions (<10), where InsertionSort beats QuickSort.
// If we have more exceptions than this in real life, we should consider moving to a QuickSort.
for (int i = 0; i < exceptions.Length; i++)
{
int least = i;
for (int j = i + 1; j < exceptions.Length; j++)
{
if (exceptions[least].IsInner(exceptions[j]))
{
least = j;
}
}
__ExceptionInfo temp = exceptions[i];
exceptions[i] = exceptions[least];
exceptions[least] = temp;
}
}
internal int[]? GetTokenFixups()
{
if (m_RelocFixupCount == 0)
{
Debug.Assert(m_RelocFixupList == null);
return null;
}
int[] narrowTokens = new int[m_RelocFixupCount];
Array.Copy(m_RelocFixupList!, narrowTokens, m_RelocFixupCount);
return narrowTokens;
}
#endregion
#region Public Members
#region Emit
public override void Emit(OpCode opcode)
{
EnsureCapacity(3);
InternalEmit(opcode);
}
public override void Emit(OpCode opcode, byte arg)
{
EnsureCapacity(4);
InternalEmit(opcode);
m_ILStream[m_length++] = arg;
}
public override void Emit(OpCode opcode, short arg)
{
// Puts opcode onto the stream of instructions followed by arg
EnsureCapacity(5);
InternalEmit(opcode);
BinaryPrimitives.WriteInt16LittleEndian(m_ILStream.AsSpan(m_length), arg);
m_length += 2;
}
public override void Emit(OpCode opcode, int arg)
{
// Special-case several opcodes that have shorter variants for common values.
if (opcode.Equals(OpCodes.Ldc_I4))
{
if (arg >= -1 && arg <= 8)
{
opcode = arg switch
{
-1 => OpCodes.Ldc_I4_M1,
0 => OpCodes.Ldc_I4_0,
1 => OpCodes.Ldc_I4_1,
2 => OpCodes.Ldc_I4_2,
3 => OpCodes.Ldc_I4_3,
4 => OpCodes.Ldc_I4_4,
5 => OpCodes.Ldc_I4_5,
6 => OpCodes.Ldc_I4_6,
7 => OpCodes.Ldc_I4_7,
_ => OpCodes.Ldc_I4_8,
};
Emit(opcode);
return;
}
if (arg >= -128 && arg <= 127)
{
Emit(OpCodes.Ldc_I4_S, (sbyte)arg);
return;
}
}
else if (opcode.Equals(OpCodes.Ldarg))
{
if ((uint)arg <= 3)
{
Emit(arg switch
{
0 => OpCodes.Ldarg_0,
1 => OpCodes.Ldarg_1,
2 => OpCodes.Ldarg_2,
_ => OpCodes.Ldarg_3,
});
return;
}
if ((uint)arg <= byte.MaxValue)
{
Emit(OpCodes.Ldarg_S, (byte)arg);
return;
}
if ((uint)arg <= ushort.MaxValue) // this will be true except on misuse of the opcode
{
Emit(OpCodes.Ldarg, (short)arg);
return;
}
}
else if (opcode.Equals(OpCodes.Ldarga))
{
if ((uint)arg <= byte.MaxValue)
{
Emit(OpCodes.Ldarga_S, (byte)arg);
return;
}
if ((uint)arg <= ushort.MaxValue) // this will be true except on misuse of the opcode
{
Emit(OpCodes.Ldarga, (short)arg);
return;
}
}
else if (opcode.Equals(OpCodes.Starg))
{
if ((uint)arg <= byte.MaxValue)
{
Emit(OpCodes.Starg_S, (byte)arg);
return;
}
if ((uint)arg <= ushort.MaxValue) // this will be true except on misuse of the opcode
{
Emit(OpCodes.Starg, (short)arg);
return;
}
}
// For everything else, put the opcode followed by the arg onto the stream of instructions.
EnsureCapacity(7);
InternalEmit(opcode);
PutInteger4(arg);
}
public override void Emit(OpCode opcode, MethodInfo meth)
{
ArgumentNullException.ThrowIfNull(meth);
if (opcode.Equals(OpCodes.Call) || opcode.Equals(OpCodes.Callvirt) || opcode.Equals(OpCodes.Newobj))
{
EmitCall(opcode, meth, null);
}
else
{
// Reflection doesn't distinguish between these two concepts:
// 1. A generic method definition: Foo`1
// 2. A generic method definition instantiated over its own generic arguments: Foo`1<!!0>
// In RefEmit, we always want 1 for Ld* opcodes and 2 for Call* and Newobj.
bool useMethodDef = opcode.Equals(OpCodes.Ldtoken) || opcode.Equals(OpCodes.Ldftn) || opcode.Equals(OpCodes.Ldvirtftn);
int tk = GetMethodToken(meth, null, useMethodDef);
EnsureCapacity(7);
InternalEmit(opcode);
UpdateStackSize(opcode, 0);
RecordTokenFixup();
PutInteger4(tk);
}
}
public override void EmitCalli(OpCode opcode, CallingConventions callingConvention,
Type? returnType, Type[]? parameterTypes, Type[]? optionalParameterTypes)
{
int stackchange = 0;
if (optionalParameterTypes != null)
{
if ((callingConvention & CallingConventions.VarArgs) == 0)
{
// Client should not supply optional parameter in default calling convention
throw new InvalidOperationException(SR.InvalidOperation_NotAVarArgCallingConvention);
}
}
ModuleBuilder modBuilder = (ModuleBuilder)m_methodBuilder.Module;
SignatureHelper sig = GetMemberRefSignature(callingConvention,
returnType,
parameterTypes,
optionalParameterTypes);
EnsureCapacity(7);
Emit(OpCodes.Calli);
// If there is a non-void return type, push one.
if (returnType != typeof(void))
stackchange++;
// Pop off arguments if any.
if (parameterTypes != null)
stackchange -= parameterTypes.Length;
// Pop off vararg arguments.
if (optionalParameterTypes != null)
stackchange -= optionalParameterTypes.Length;
// Pop the this parameter if the method has a this parameter.
if ((callingConvention & CallingConventions.HasThis) == CallingConventions.HasThis)
stackchange--;
// Pop the native function pointer.
stackchange--;
UpdateStackSize(OpCodes.Calli, stackchange);
RecordTokenFixup();
PutInteger4(modBuilder.GetSignatureMetadataToken(sig));
}
public override void EmitCalli(OpCode opcode, CallingConvention unmanagedCallConv, Type? returnType, Type[]? parameterTypes)
{
int stackchange = 0;
int cParams = 0;
ModuleBuilder modBuilder = (ModuleBuilder)m_methodBuilder.Module;
if (parameterTypes != null)
{
cParams = parameterTypes.Length;
}
SignatureHelper sig = SignatureHelper.GetMethodSigHelper(
modBuilder,
unmanagedCallConv,
returnType);
if (parameterTypes != null)
{
for (int i = 0; i < cParams; i++)
{
sig.AddArgument(parameterTypes[i]);
}
}
// If there is a non-void return type, push one.
if (returnType != typeof(void))
stackchange++;
// Pop off arguments if any.
if (parameterTypes != null)
stackchange -= cParams;
// Pop the native function pointer.
stackchange--;
UpdateStackSize(OpCodes.Calli, stackchange);
EnsureCapacity(7);
Emit(OpCodes.Calli);
RecordTokenFixup();
PutInteger4(modBuilder.GetSignatureMetadataToken(sig));
}
public override void EmitCall(OpCode opcode, MethodInfo methodInfo, Type[]? optionalParameterTypes)
{
ArgumentNullException.ThrowIfNull(methodInfo);
if (!(opcode.Equals(OpCodes.Call) || opcode.Equals(OpCodes.Callvirt) || opcode.Equals(OpCodes.Newobj)))
throw new ArgumentException(SR.Argument_NotMethodCallOpcode, nameof(opcode));
int stackchange = 0;
int tk = GetMethodToken(methodInfo, optionalParameterTypes, false);
EnsureCapacity(7);
InternalEmit(opcode);
// Push the return value if there is one.
if (methodInfo.ReturnType != typeof(void))
stackchange++;
// Pop the parameters.
Type[] parameters = methodInfo.GetParameterTypes();
if (parameters != null)
stackchange -= parameters.Length;
// Pop the this parameter if the method is non-static and the
// instruction is not newobj.
if (!(methodInfo is SymbolMethod) && !methodInfo.IsStatic && !opcode.Equals(OpCodes.Newobj))
stackchange--;
// Pop the optional parameters off the stack.
if (optionalParameterTypes != null)
stackchange -= optionalParameterTypes.Length;
UpdateStackSize(opcode, stackchange);
RecordTokenFixup();
PutInteger4(tk);
}
public override void Emit(OpCode opcode, SignatureHelper signature)
{
ArgumentNullException.ThrowIfNull(signature);
int stackchange = 0;
ModuleBuilder modBuilder = (ModuleBuilder)m_methodBuilder.Module;
int sig = modBuilder.GetSignatureMetadataToken(signature);
int tempVal = sig;
EnsureCapacity(7);
InternalEmit(opcode);
// The only IL instruction that has VarPop behaviour, that takes a
// Signature token as a parameter is calli. Pop the parameters and
// the native function pointer. To be conservative, do not pop the
// this pointer since this information is not easily derived from
// SignatureHelper.
if (opcode.StackBehaviourPop == StackBehaviour.Varpop)
{
Debug.Assert(opcode.Equals(OpCodes.Calli),
"Unexpected opcode encountered for StackBehaviour VarPop.");
// Pop the arguments..
stackchange -= signature.ArgumentCount;
// Pop native function pointer off the stack.
stackchange--;
UpdateStackSize(opcode, stackchange);
}
RecordTokenFixup();
PutInteger4(tempVal);
}
public override void Emit(OpCode opcode, ConstructorInfo con)
{
ArgumentNullException.ThrowIfNull(con);
int stackchange = 0;
// Constructors cannot be generic so the value of UseMethodDef doesn't matter.
int tk = GetMethodToken(con, null, true);
EnsureCapacity(7);
InternalEmit(opcode);
// Make a conservative estimate by assuming a return type and no
// this parameter.
if (opcode.StackBehaviourPush == StackBehaviour.Varpush)
{
// Instruction must be one of call or callvirt.
Debug.Assert(opcode.Equals(OpCodes.Call) ||
opcode.Equals(OpCodes.Callvirt),
"Unexpected opcode encountered for StackBehaviour of VarPush.");
stackchange++;
}
if (opcode.StackBehaviourPop == StackBehaviour.Varpop)
{
// Instruction must be one of call, callvirt or newobj.
Debug.Assert(opcode.Equals(OpCodes.Call) ||
opcode.Equals(OpCodes.Callvirt) ||
opcode.Equals(OpCodes.Newobj),
"Unexpected opcode encountered for StackBehaviour of VarPop.");
Type[] parameters = con.GetParameterTypes();
if (parameters != null)
stackchange -= parameters.Length;
}
UpdateStackSize(opcode, stackchange);
RecordTokenFixup();
PutInteger4(tk);
}
public override void Emit(OpCode opcode, Type cls)
{
// Puts opcode onto the stream and then the metadata token represented
// by cls. The location of cls is recorded so that the token can be
// patched if necessary when persisting the module to a PE.
RuntimeModuleBuilder modBuilder = (RuntimeModuleBuilder)m_methodBuilder.Module;
bool getGenericDefinition = (opcode == OpCodes.Ldtoken && cls != null && cls.IsGenericTypeDefinition);
int tempVal = modBuilder.GetTypeTokenInternal(cls!, getGenericDefinition);
EnsureCapacity(7);
InternalEmit(opcode);
RecordTokenFixup();
PutInteger4(tempVal);
}
public override void Emit(OpCode opcode, long arg)
{
EnsureCapacity(11);
InternalEmit(opcode);
BinaryPrimitives.WriteInt64LittleEndian(m_ILStream.AsSpan(m_length), arg);
m_length += 8;
}
public override void Emit(OpCode opcode, float arg)
{
EnsureCapacity(7);
InternalEmit(opcode);
BinaryPrimitives.WriteInt32LittleEndian(m_ILStream.AsSpan(m_length), BitConverter.SingleToInt32Bits(arg));
m_length += 4;
}
public override void Emit(OpCode opcode, double arg)
{
EnsureCapacity(11);
InternalEmit(opcode);
BinaryPrimitives.WriteInt64LittleEndian(m_ILStream.AsSpan(m_length), BitConverter.DoubleToInt64Bits(arg));
m_length += 8;
}
public override void Emit(OpCode opcode, Label label)
{
// Puts opcode onto the stream and leaves space to include label
// when fixups are done. Labels are created using ILGenerator.DefineLabel and
// their location within the stream is fixed by using ILGenerator.MarkLabel.
// If a single-byte instruction (designated by the _S suffix in OpCodes.cs) is used,
// the label can represent a jump of at most 127 bytes along the stream.
//
// opcode must represent a branch instruction (although we don't explicitly
// verify this). Since branches are relative instructions, label will be replaced with the
// correct offset to branch during the fixup process.
EnsureCapacity(7);
InternalEmit(opcode);
if (OpCodes.TakesSingleByteArgument(opcode))
{
AddFixup(label, m_length++, 1);
}
else
{
AddFixup(label, m_length, 4);
m_length += 4;
}
}
public override void Emit(OpCode opcode, Label[] labels)
{
ArgumentNullException.ThrowIfNull(labels);
// Emitting a switch table
int i;
int remaining; // number of bytes remaining for this switch instruction to be subtracted
// for computing the offset
int count = labels.Length;
EnsureCapacity(count * 4 + 7);
InternalEmit(opcode);
PutInteger4(count);
for (remaining = count * 4, i = 0; remaining > 0; remaining -= 4, i++)
{
AddFixup(labels[i], m_length, remaining);
m_length += 4;
}
}
public override void Emit(OpCode opcode, FieldInfo field)
{
ModuleBuilder modBuilder = (ModuleBuilder)m_methodBuilder.Module;
int tempVal = modBuilder.GetFieldMetadataToken(field);
EnsureCapacity(7);
InternalEmit(opcode);
RecordTokenFixup();
PutInteger4(tempVal);
}
public override void Emit(OpCode opcode, string str)
{
// Puts the opcode onto the IL stream followed by the metadata token
// represented by str. The location of str is recorded for future
// fixups if the module is persisted to a PE.
ModuleBuilder modBuilder = (ModuleBuilder)m_methodBuilder.Module;
int tempVal = modBuilder.GetStringMetadataToken(str);
EnsureCapacity(7);
InternalEmit(opcode);
PutInteger4(tempVal);
}
public override void Emit(OpCode opcode, LocalBuilder local)
{
ArgumentNullException.ThrowIfNull(local);
// Puts the opcode onto the IL stream followed by the information for local variable local.
int tempVal = local.LocalIndex;
if (local is not RuntimeLocalBuilder localBuilder || localBuilder.GetMethodBuilder() != m_methodBuilder)
{
throw new ArgumentException(SR.Argument_UnmatchedMethodForLocal, nameof(local));
}
// If the instruction is a ldloc, ldloca a stloc, morph it to the optimal form.
if (opcode.Equals(OpCodes.Ldloc))
{
switch (tempVal)
{
case 0:
opcode = OpCodes.Ldloc_0;
break;
case 1:
opcode = OpCodes.Ldloc_1;
break;
case 2:
opcode = OpCodes.Ldloc_2;
break;
case 3:
opcode = OpCodes.Ldloc_3;
break;
default:
if (tempVal <= 255)
opcode = OpCodes.Ldloc_S;
break;
}
}
else if (opcode.Equals(OpCodes.Stloc))
{
switch (tempVal)
{
case 0:
opcode = OpCodes.Stloc_0;
break;
case 1:
opcode = OpCodes.Stloc_1;
break;
case 2:
opcode = OpCodes.Stloc_2;
break;
case 3:
opcode = OpCodes.Stloc_3;
break;
default:
if (tempVal <= 255)
opcode = OpCodes.Stloc_S;
break;
}
}
else if (opcode.Equals(OpCodes.Ldloca))
{
if (tempVal <= 255)
opcode = OpCodes.Ldloca_S;
}
EnsureCapacity(7);
InternalEmit(opcode);
if (opcode.OperandType == OperandType.InlineNone)
return;
if (!OpCodes.TakesSingleByteArgument(opcode))
{
BinaryPrimitives.WriteInt16LittleEndian(m_ILStream.AsSpan(m_length), (short)tempVal);
m_length += 2;
}
else
{
// Handle stloc_1, ldloc_1
if (tempVal > byte.MaxValue)
{
throw new InvalidOperationException(SR.InvalidOperation_BadInstructionOrIndexOutOfBound);
}
m_ILStream[m_length++] = (byte)tempVal;
}
}
#endregion
#region Exceptions
public override Label BeginExceptionBlock()
{
// Begin an Exception block. Creating an Exception block records some information,
// but does not actually emit any IL onto the stream. Exceptions should be created and
// marked in the following form:
//
// Emit Some IL
// BeginExceptionBlock
// Emit the IL which should appear within the "try" block
// BeginCatchBlock
// Emit the IL which should appear within the "catch" block
// Optional: BeginCatchBlock (this can be repeated an arbitrary number of times
// EndExceptionBlock
// Delay init
m_exceptions ??= new __ExceptionInfo[DefaultExceptionArraySize];
m_currExcStack ??= new __ExceptionInfo[DefaultExceptionArraySize];
if (m_exceptionCount >= m_exceptions.Length)
{
m_exceptions = EnlargeArray(m_exceptions);
}
if (m_currExcStackCount >= m_currExcStack.Length)
{
m_currExcStack = EnlargeArray(m_currExcStack);
}
Label endLabel = DefineLabel(0);
__ExceptionInfo exceptionInfo = new __ExceptionInfo(m_length, endLabel);
// add the exception to the tracking list
m_exceptions[m_exceptionCount++] = exceptionInfo;
// Make this exception the current active exception
m_currExcStack[m_currExcStackCount++] = exceptionInfo;
// Stack depth for "try" starts at zero.
m_curDepth = 0;
return endLabel;
}
public override void EndExceptionBlock()
{
if (m_currExcStackCount == 0)
{
throw new NotSupportedException(SR.Argument_NotInExceptionBlock);
}
// Pop the current exception block
__ExceptionInfo current = m_currExcStack![m_currExcStackCount - 1];
m_currExcStack[--m_currExcStackCount] = null!;
Label endLabel = current.GetEndLabel();
int state = current.GetCurrentState();
if (state == __ExceptionInfo.State_Filter ||
state == __ExceptionInfo.State_Try)
{
throw new InvalidOperationException(SR.Argument_BadExceptionCodeGen);
}
if (state == __ExceptionInfo.State_Catch)
{
Emit(OpCodes.Leave, endLabel);
}
else if (state == __ExceptionInfo.State_Finally || state == __ExceptionInfo.State_Fault)
{
Emit(OpCodes.Endfinally);
}
// Check if we've already set this label.
// The only reason why we might have set this is if we have a finally block.
Label label = m_labelList![endLabel.Id].m_pos != -1
? current.m_finallyEndLabel
: endLabel;
MarkLabel(label);
current.Done(m_length);
}
public override void BeginExceptFilterBlock()
{
// Begins an exception filter block. Emits a branch instruction to the end of the current exception block.
if (m_currExcStackCount == 0)
throw new NotSupportedException(SR.Argument_NotInExceptionBlock);
__ExceptionInfo current = m_currExcStack![m_currExcStackCount - 1];
Emit(OpCodes.Leave, current.GetEndLabel());
current.MarkFilterAddr(m_length);
// Stack depth for "filter" starts at one.
m_curDepth = 1;
}
public override void BeginCatchBlock(Type? exceptionType)
{
// Begins a catch block. Emits a branch instruction to the end of the current exception block.
if (m_currExcStackCount == 0)
{
throw new NotSupportedException(SR.Argument_NotInExceptionBlock);
}
__ExceptionInfo current = m_currExcStack![m_currExcStackCount - 1];
if (current.GetCurrentState() == __ExceptionInfo.State_Filter)
{
if (exceptionType != null)
{
throw new ArgumentException(SR.Argument_ShouldNotSpecifyExceptionType);
}
Emit(OpCodes.Endfilter);
}
else
{
// execute this branch if previous clause is Catch or Fault
ArgumentNullException.ThrowIfNull(exceptionType);
Emit(OpCodes.Leave, current.GetEndLabel());
}
current.MarkCatchAddr(m_length, exceptionType);
// Stack depth for "catch" starts at one.
m_curDepth = 1;
}
public override void BeginFaultBlock()
{
if (m_currExcStackCount == 0)
{
throw new NotSupportedException(SR.Argument_NotInExceptionBlock);
}
__ExceptionInfo current = m_currExcStack![m_currExcStackCount - 1];
// emit the leave for the clause before this one.
Emit(OpCodes.Leave, current.GetEndLabel());
current.MarkFaultAddr(m_length);
// Stack depth for "fault" starts at zero.
m_curDepth = 0;
}
public override void BeginFinallyBlock()
{
if (m_currExcStackCount == 0)
{
throw new NotSupportedException(SR.Argument_NotInExceptionBlock);
}
__ExceptionInfo current = m_currExcStack![m_currExcStackCount - 1];
int state = current.GetCurrentState();
Label endLabel = current.GetEndLabel();
int catchEndAddr = 0;
if (state != __ExceptionInfo.State_Try)
{
// generate leave for any preceding catch clause
Emit(OpCodes.Leave, endLabel);
catchEndAddr = m_length;
}
MarkLabel(endLabel);
Label finallyEndLabel = DefineLabel(0);
current.SetFinallyEndLabel(finallyEndLabel);
// generate leave for try clause
Emit(OpCodes.Leave, finallyEndLabel);
if (catchEndAddr == 0)
catchEndAddr = m_length;
current.MarkFinallyAddr(m_length, catchEndAddr);
// Stack depth for "finally" starts at zero.
m_curDepth = 0;
}
#endregion
#region Labels
public override Label DefineLabel()
{
// We don't know the stack depth at the label yet, so set it to -1.
return DefineLabel(-1);
}
private Label DefineLabel(int depth)
{
// Declares a new Label. This is just a token and does not yet represent any particular location
// within the stream. In order to set the position of the label within the stream, you must call
// Mark Label.
Debug.Assert(depth >= -1);
// Delay init the label array in case we dont use it
m_labelList ??= new __LabelInfo[DefaultLabelArraySize];
if (m_labelCount >= m_labelList.Length)
{
m_labelList = EnlargeArray(m_labelList);
}
m_labelList[m_labelCount].m_pos = -1;
m_labelList[m_labelCount].m_depth = depth;
return new Label(m_labelCount++);
}
public override void MarkLabel(Label loc)
{
// Defines a label by setting the position where that label is found within the stream.
// Does not allow a label to be defined more than once.
int labelIndex = loc.Id;
// This should only happen if a label from another generator is used with this one.
if (m_labelList is null || labelIndex < 0 || labelIndex >= m_labelList.Length)
{
throw new ArgumentException(SR.Argument_InvalidLabel);
}
if (m_labelList[labelIndex].m_pos != -1)
{
throw new ArgumentException(SR.Argument_RedefinedLabel);
}
m_labelList[labelIndex].m_pos = m_length;
int depth = m_labelList[labelIndex].m_depth;
if (depth < 0)
{
// Unknown depth for this label, indicating that it hasn't been used yet.
// If m_curDepth is unknown, we're in the Backward branch constraint case. See ECMA-335 III.1.7.5.
// The m_depthAdjustment field will compensate for violations of this constraint, as we
// discover them. That is, here we assume a depth of zero. If a (later) branch to this label
// has a positive stack depth, we'll record that as the new depth and add the delta into
// m_depthAdjustment.
if (m_curDepth < 0)
m_curDepth = 0;
m_labelList[labelIndex].m_depth = m_curDepth;
}
else if (depth < m_curDepth)
{
// A branch location with smaller stack targets this label. In this case, the IL is
// invalid, but we just compensate for it.
m_depthAdjustment += m_curDepth - depth;
m_labelList[labelIndex].m_depth = m_curDepth;
}
else if (depth > m_curDepth)
{
// Either the current depth is unknown, or a branch location with larger stack targets
// this label, so the IL is invalid. In either case, just adjust the current depth.
m_curDepth = depth;
}
}
#endregion
#region Debug API
public override LocalBuilder DeclareLocal(Type localType, bool pinned)
{
// Declare a local of type "local". The current active lexical scope
// will be the scope that local will live.
if (m_methodBuilder is not RuntimeMethodBuilder methodBuilder)
throw new NotSupportedException();
if (methodBuilder.IsTypeCreated())
{
// cannot change method after its containing type has been created
throw new InvalidOperationException(SR.InvalidOperation_TypeHasBeenCreated);
}
ArgumentNullException.ThrowIfNull(localType);
if (methodBuilder.m_bIsBaked)
{
throw new InvalidOperationException(SR.InvalidOperation_MethodBaked);
}
// add the localType to local signature
m_localSignature.AddArgument(localType, pinned);
return new RuntimeLocalBuilder(m_localCount++, localType, methodBuilder, pinned);
}
public override void UsingNamespace(string usingNamespace)
{
// Specifying the namespace to be used in evaluating locals and watches
// for the current active lexical scope.
ArgumentException.ThrowIfNullOrEmpty(usingNamespace);
if (m_methodBuilder is not RuntimeMethodBuilder methodBuilder)
throw new NotSupportedException();
int index = ((RuntimeILGenerator)methodBuilder.GetILGenerator()).m_ScopeTree.GetCurrentActiveScopeIndex();
if (index == -1)
{
methodBuilder.m_localSymInfo!.AddUsingNamespace(usingNamespace);
}
else
{
m_ScopeTree.AddUsingNamespaceToCurrentScope(usingNamespace);
}
}
public override void BeginScope()
{
m_ScopeTree.AddScopeInfo(ScopeAction.Open, m_length);
}
public override void EndScope()
{
m_ScopeTree.AddScopeInfo(ScopeAction.Close, m_length);
}
public override int ILOffset => m_length;
#endregion
#endregion
}
internal struct __LabelInfo
{
internal int m_pos; // Position in the il stream, with -1 meaning unknown.
internal int m_depth; // Stack depth, with -1 meaning unknown.
}
internal struct __FixupData
{
internal Label m_fixupLabel;
internal int m_fixupPos;
internal int m_fixupInstSize;
}
internal sealed class __ExceptionInfo
{
internal const int None = 0x0000; // COR_ILEXCEPTION_CLAUSE_NONE
internal const int Filter = 0x0001; // COR_ILEXCEPTION_CLAUSE_FILTER
internal const int Finally = 0x0002; // COR_ILEXCEPTION_CLAUSE_FINALLY
internal const int Fault = 0x0004; // COR_ILEXCEPTION_CLAUSE_FAULT
internal const int PreserveStack = 0x0004; // COR_ILEXCEPTION_CLAUSE_PRESERVESTACK
internal const int State_Try = 0;
internal const int State_Filter = 1;
internal const int State_Catch = 2;
internal const int State_Finally = 3;
internal const int State_Fault = 4;
internal const int State_Done = 5;
internal int m_startAddr;
internal int[] m_filterAddr;
internal int[] m_catchAddr;
internal int[] m_catchEndAddr;
internal int[] m_type;
internal Type[] m_catchClass;
internal Label m_endLabel;
internal Label m_finallyEndLabel;
internal int m_endAddr;
internal int m_endFinally;
internal int m_currentCatch;
private int m_currentState;
internal __ExceptionInfo(int startAddr, Label endLabel)
{
m_startAddr = startAddr;
m_endAddr = -1;
m_filterAddr = new int[4];
m_catchAddr = new int[4];
m_catchEndAddr = new int[4];
m_catchClass = new Type[4];
m_currentCatch = 0;
m_endLabel = endLabel;
m_type = new int[4];
m_endFinally = -1;
m_currentState = State_Try;
}
private void MarkHelper(
int catchorfilterAddr, // the starting address of a clause
int catchEndAddr, // the end address of a previous catch clause. Only use when finally is following a catch
Type? catchClass, // catch exception type
int type) // kind of clause
{
int currentCatch = m_currentCatch;
if (currentCatch >= m_catchAddr.Length)
{
m_filterAddr = RuntimeILGenerator.EnlargeArray(m_filterAddr);
m_catchAddr = RuntimeILGenerator.EnlargeArray(m_catchAddr);
m_catchEndAddr = RuntimeILGenerator.EnlargeArray(m_catchEndAddr);
m_catchClass = RuntimeILGenerator.EnlargeArray(m_catchClass);
m_type = RuntimeILGenerator.EnlargeArray(m_type);
}
if (type == Filter)
{
m_type[currentCatch] = type;
m_filterAddr[currentCatch] = catchorfilterAddr;
m_catchAddr[currentCatch] = -1;
if (currentCatch > 0)
{
Debug.Assert(m_catchEndAddr[currentCatch - 1] == -1, "m_catchEndAddr[m_currentCatch-1] == -1");
m_catchEndAddr[currentCatch - 1] = catchorfilterAddr;
}
}
else
{
// catch or Fault clause
m_catchClass[currentCatch] = catchClass!;
if (m_type[currentCatch] != Filter)
{
m_type[currentCatch] = type;
}
m_catchAddr[currentCatch] = catchorfilterAddr;
if (currentCatch > 0)
{
if (m_type[currentCatch] != Filter)
{
Debug.Assert(m_catchEndAddr[currentCatch - 1] == -1, "m_catchEndAddr[m_currentCatch-1] == -1");
m_catchEndAddr[currentCatch - 1] = catchEndAddr;
}
}
m_catchEndAddr[currentCatch] = -1;
m_currentCatch++;
}
if (m_endAddr == -1)
{
m_endAddr = catchorfilterAddr;
}
}
internal void MarkFilterAddr(int filterAddr)
{
m_currentState = State_Filter;
MarkHelper(filterAddr, filterAddr, null, Filter);
}
internal void MarkFaultAddr(int faultAddr)
{
m_currentState = State_Fault;
MarkHelper(faultAddr, faultAddr, null, Fault);
}
internal void MarkCatchAddr(int catchAddr, Type? catchException)
{
m_currentState = State_Catch;
MarkHelper(catchAddr, catchAddr, catchException, None);
}
internal void MarkFinallyAddr(int finallyAddr, int endCatchAddr)
{
if (m_endFinally != -1)
{
throw new ArgumentException(SR.Argument_TooManyFinallyClause);
}
m_currentState = State_Finally;
m_endFinally = finallyAddr;
MarkHelper(finallyAddr, endCatchAddr, null, Finally);
}
internal void Done(int endAddr)
{
Debug.Assert(m_currentCatch > 0, "m_currentCatch > 0");
Debug.Assert(m_catchAddr[m_currentCatch - 1] > 0, "m_catchAddr[m_currentCatch-1] > 0");
Debug.Assert(m_catchEndAddr[m_currentCatch - 1] == -1, "m_catchEndAddr[m_currentCatch-1] == -1");
m_catchEndAddr[m_currentCatch - 1] = endAddr;
m_currentState = State_Done;
}
internal int GetStartAddress()
{
return m_startAddr;
}
internal int GetEndAddress()
{
return m_endAddr;
}
internal int GetFinallyEndAddress()
{
return m_endFinally;
}
internal Label GetEndLabel()
{
return m_endLabel;
}
internal int[] GetFilterAddresses()
{
return m_filterAddr;
}
internal int[] GetCatchAddresses()
{
return m_catchAddr;
}
internal int[] GetCatchEndAddresses()
{
return m_catchEndAddr;
}
internal Type[] GetCatchClass()
{
return m_catchClass;
}
internal int GetNumberOfCatches()
{
return m_currentCatch;
}
internal int[] GetExceptionTypes()
{
return m_type;
}
internal void SetFinallyEndLabel(Label lbl)
{
m_finallyEndLabel = lbl;
}
internal Label GetFinallyEndLabel()
{
return m_finallyEndLabel;
}
// Specifies whether exc is an inner exception for "this". The way
// its determined is by comparing the end address for the last catch
// clause for both exceptions. If they're the same, the start address
// for the exception is compared.
// WARNING: This is not a generic function to determine the innerness
// of an exception. This is somewhat of a mis-nomer. This gives a
// random result for cases where the two exceptions being compared do
// not having a nesting relation.
internal bool IsInner(__ExceptionInfo exc)
{
Debug.Assert(exc != null);
Debug.Assert(m_currentCatch > 0, "m_currentCatch > 0");
Debug.Assert(exc.m_currentCatch > 0, "exc.m_currentCatch > 0");
int exclast = exc.m_currentCatch - 1;
int last = m_currentCatch - 1;
if (exc.m_catchEndAddr[exclast] < m_catchEndAddr[last])
return true;
if (exc.m_catchEndAddr[exclast] != m_catchEndAddr[last])
return false;
Debug.Assert(exc.GetEndAddress() != GetEndAddress(),
"exc.GetEndAddress() != GetEndAddress()");
return exc.GetEndAddress() > GetEndAddress();
}
// 0 indicates in a try block
// 1 indicates in a filter block
// 2 indicates in a catch block
// 3 indicates in a finally block
// 4 indicates Done
internal int GetCurrentState()
{
return m_currentState;
}
}
/// <summary>
/// Scope Tree is a class that track the scope structure within a method body
/// It keeps track two parallel array. m_ScopeAction keeps track the action. It can be
/// OpenScope or CloseScope. m_iOffset records the offset where the action
/// takes place.
/// </summary>
internal enum ScopeAction : sbyte
{
Open = -0x1,
Close = 0x1
}
internal sealed class ScopeTree
{
internal ScopeTree()
{
// initialize data variables
m_iOpenScopeCount = 0;
m_iCount = 0;
}
/// <summary>
/// Find the current active lexical scope. For example, if we have
/// "Open Open Open Close",
/// we will return 1 as the second BeginScope is currently active.
/// </summary>
internal int GetCurrentActiveScopeIndex()
{
if (m_iCount == 0)
{
return -1;
}
int i = m_iCount - 1;
for (int cClose = 0; cClose > 0 || m_ScopeActions[i] == ScopeAction.Close; i--)
{
cClose += (sbyte)m_ScopeActions[i];
}
return i;
}
internal void AddLocalSymInfoToCurrentScope(
string strName,
byte[] signature,
int slot,
int startOffset,
int endOffset)
{
int i = GetCurrentActiveScopeIndex();
m_localSymInfos[i] ??= new LocalSymInfo();
m_localSymInfos[i]!.AddLocalSymInfo(strName, signature, slot, startOffset, endOffset);
}
internal void AddUsingNamespaceToCurrentScope(string strNamespace)
{
int i = GetCurrentActiveScopeIndex();
m_localSymInfos[i] ??= new LocalSymInfo();
m_localSymInfos[i]!.AddUsingNamespace(strNamespace);
}
internal void AddScopeInfo(ScopeAction sa, int iOffset)
{
if (sa == ScopeAction.Close && m_iOpenScopeCount <= 0)
{
throw new ArgumentException(SR.Argument_UnmatchingSymScope);
}
// make sure that arrays are large enough to hold addition info
EnsureCapacity();
m_ScopeActions[m_iCount] = sa;
m_iOffsets[m_iCount] = iOffset;
m_localSymInfos[m_iCount] = null;
checked { m_iCount++; }
m_iOpenScopeCount += -(sbyte)sa;
}
/// <summary>
/// Helper to ensure arrays are large enough
/// </summary>
internal void EnsureCapacity()
{
if (m_iCount == 0)
{
// First time. Allocate the arrays.
m_iOffsets = new int[InitialSize];
m_ScopeActions = new ScopeAction[InitialSize];
m_localSymInfos = new LocalSymInfo[InitialSize];
}
else if (m_iCount == m_iOffsets.Length)
{
// the arrays are full. Enlarge the arrays
// It would probably be simpler to just use Lists here.
int newSize = checked(m_iCount * 2);
int[] temp = new int[newSize];
Array.Copy(m_iOffsets, temp, m_iCount);
m_iOffsets = temp;
ScopeAction[] tempSA = new ScopeAction[newSize];
Array.Copy(m_ScopeActions, tempSA, m_iCount);
m_ScopeActions = tempSA;
LocalSymInfo[] tempLSI = new LocalSymInfo[newSize];
Array.Copy(m_localSymInfos, tempLSI, m_iCount);
m_localSymInfos = tempLSI;
}
}
internal int[] m_iOffsets = null!; // array of offsets
internal ScopeAction[] m_ScopeActions = null!; // array of scope actions
internal int m_iCount; // how many entries in the arrays are occupied
internal int m_iOpenScopeCount; // keep track how many scopes are open
internal const int InitialSize = 16;
internal LocalSymInfo?[] m_localSymInfos = null!; // keep track debugging local information
}
}
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