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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;
using Internal.TypeSystem;
using Debug = System.Diagnostics.Debug;
namespace Internal.IL.Stubs
{
internal struct ArrayMethodILEmitter
{
private ArrayMethod _method;
private TypeDesc _elementType;
private int _rank;
private ILToken _helperFieldToken;
private ILEmitter _emitter;
private ArrayMethodILEmitter(ArrayMethod method)
{
Debug.Assert(method.Kind != ArrayMethodKind.Address, "Should be " + nameof(ArrayMethodKind.AddressWithHiddenArg));
_method = method;
ArrayType arrayType = (ArrayType)method.OwningType;
_rank = arrayType.Rank;
_elementType = arrayType.ElementType;
_emitter = new ILEmitter();
// This helper field is needed to generate proper GC tracking. There is no direct way
// to create interior pointer.
_helperFieldToken = _emitter.NewToken(_method.Context.GetWellKnownType(WellKnownType.Object).GetKnownField("m_pEEType"));
}
private void EmitLoadInteriorAddress(ILCodeStream codeStream, int offset)
{
codeStream.EmitLdArg(0); // this
codeStream.Emit(ILOpcode.ldflda, _helperFieldToken);
codeStream.EmitLdc(offset);
codeStream.Emit(ILOpcode.add);
}
private MethodIL EmitIL()
{
switch (_method.Kind)
{
case ArrayMethodKind.Get:
case ArrayMethodKind.Set:
case ArrayMethodKind.AddressWithHiddenArg:
EmitILForAccessor();
break;
case ArrayMethodKind.Ctor:
// .ctor is implemented as a JIT helper and the JIT shouldn't be asking for the IL.
default:
// Asking for anything else is invalid.
throw new InvalidOperationException();
}
return _emitter.Link(_method);
}
public static MethodIL EmitIL(ArrayMethod arrayMethod)
{
return new ArrayMethodILEmitter(arrayMethod).EmitIL();
}
private void EmitILForAccessor()
{
Debug.Assert(_method.OwningType.IsMdArray);
var codeStream = _emitter.NewCodeStream();
var context = _method.Context;
var int32Type = context.GetWellKnownType(WellKnownType.Int32);
var totalLocalNum = _emitter.NewLocal(int32Type);
var lengthLocalNum = _emitter.NewLocal(int32Type);
int pointerSize = context.Target.PointerSize;
int argStartOffset = _method.Kind == ArrayMethodKind.AddressWithHiddenArg ? 2 : 1;
var rangeExceptionLabel = _emitter.NewCodeLabel();
ILCodeLabel typeMismatchExceptionLabel = null;
if (_elementType.IsGCPointer)
{
// Type check
if (_method.Kind == ArrayMethodKind.Set)
{
MethodDesc checkArrayStore =
context.SystemModule.GetKnownType("System.Runtime", "RuntimeImports").GetKnownMethod("RhCheckArrayStore", null);
codeStream.EmitLdArg(0);
codeStream.EmitLdArg(_rank + argStartOffset);
codeStream.Emit(ILOpcode.call, _emitter.NewToken(checkArrayStore));
}
else if (_method.Kind == ArrayMethodKind.AddressWithHiddenArg)
{
TypeDesc objectType = context.GetWellKnownType(WellKnownType.Object);
TypeDesc eetypeType = context.SystemModule.GetKnownType("Internal.Runtime", "MethodTable");
typeMismatchExceptionLabel = _emitter.NewCodeLabel();
ILCodeLabel typeCheckPassedLabel = _emitter.NewCodeLabel();
// Codegen will pass a null hidden argument if this is a `constrained.` call to the Address method.
// As per ECMA-335 III.2.3, the prefix suppresses the type check.
// if (hiddenArg == IntPtr.Zero)
// goto TypeCheckPassed;
codeStream.EmitLdArg(1);
codeStream.Emit(ILOpcode.brfalse, typeCheckPassedLabel);
// MethodTable* actualElementType = this.m_pEEType->RelatedParameterType; // ArrayElementType
codeStream.EmitLdArg(0);
codeStream.Emit(ILOpcode.ldfld, _emitter.NewToken(objectType.GetKnownField("m_pEEType")));
codeStream.Emit(ILOpcode.call,
_emitter.NewToken(eetypeType.GetKnownMethod("get_RelatedParameterType", null)));
// MethodTable* expectedElementType = hiddenArg->RelatedParameterType; // ArrayElementType
codeStream.EmitLdArg(1);
codeStream.Emit(ILOpcode.call,
_emitter.NewToken(eetypeType.GetKnownMethod("get_RelatedParameterType", null)));
// if (TypeCast.AreTypesEquivalent(expectedElementType, actualElementType))
// ThrowHelpers.ThrowArrayTypeMismatchException();
codeStream.Emit(ILOpcode.call, _emitter.NewToken(
context.SystemModule.GetKnownType("System.Runtime", "TypeCast").GetKnownMethod("AreTypesEquivalent", null)));
codeStream.Emit(ILOpcode.brfalse, typeMismatchExceptionLabel);
codeStream.EmitLabel(typeCheckPassedLabel);
}
}
// Methods on Rank 1 MdArray need to be able to handle `this` that is an SzArray
// because SzArray is castable to Rank 1 MdArray (but not the other way around).
ILCodeLabel rangeCheckDoneLabel = null;
if (_rank == 1)
{
TypeDesc objectType = context.GetWellKnownType(WellKnownType.Object);
TypeDesc eetypeType = context.SystemModule.GetKnownType("Internal.Runtime", "MethodTable");
codeStream.EmitLdArg(0);
codeStream.Emit(ILOpcode.ldfld, _emitter.NewToken(objectType.GetKnownField("m_pEEType")));
codeStream.Emit(ILOpcode.call,
_emitter.NewToken(eetypeType.GetKnownMethod("get_IsSzArray", null)));
ILCodeLabel notSzArrayLabel = _emitter.NewCodeLabel();
codeStream.Emit(ILOpcode.brfalse, notSzArrayLabel);
// We have an SzArray - do the bounds check differently
EmitLoadInteriorAddress(codeStream, pointerSize);
codeStream.Emit(ILOpcode.dup);
codeStream.Emit(ILOpcode.ldind_i4);
codeStream.EmitLdArg(argStartOffset);
codeStream.EmitStLoc(totalLocalNum);
codeStream.EmitLdLoc(totalLocalNum);
codeStream.Emit(ILOpcode.ble_un, rangeExceptionLabel);
codeStream.EmitLdc(pointerSize);
codeStream.Emit(ILOpcode.add);
rangeCheckDoneLabel = _emitter.NewCodeLabel();
codeStream.Emit(ILOpcode.br, rangeCheckDoneLabel);
codeStream.EmitLabel(notSzArrayLabel);
}
for (int i = 0; i < _rank; i++)
{
// The first two fields are MethodTable pointer and total length. Lengths for each dimension follows.
int lengthOffset = (2 * pointerSize + i * sizeof(int));
EmitLoadInteriorAddress(codeStream, lengthOffset);
codeStream.Emit(ILOpcode.ldind_i4);
codeStream.EmitStLoc(lengthLocalNum);
codeStream.EmitLdArg(i + argStartOffset);
// Compare with length
codeStream.Emit(ILOpcode.dup);
codeStream.EmitLdLoc(lengthLocalNum);
codeStream.Emit(ILOpcode.bge_un, rangeExceptionLabel);
// Add to the running total if we have one already
if (i > 0)
{
codeStream.EmitLdLoc(totalLocalNum);
codeStream.EmitLdLoc(lengthLocalNum);
codeStream.Emit(ILOpcode.mul);
codeStream.Emit(ILOpcode.add);
}
codeStream.EmitStLoc(totalLocalNum);
}
// Compute element offset
// TODO: This leaves unused space for lower bounds to match CoreCLR...
int firstElementOffset = (2 * pointerSize + 2 * _rank * sizeof(int));
EmitLoadInteriorAddress(codeStream, firstElementOffset);
if (rangeCheckDoneLabel != null)
codeStream.EmitLabel(rangeCheckDoneLabel);
codeStream.EmitLdLoc(totalLocalNum);
codeStream.Emit(ILOpcode.conv_u);
int elementSize = _elementType.GetElementSize().AsInt;
if (elementSize != 1)
{
codeStream.EmitLdc(elementSize);
codeStream.Emit(ILOpcode.mul);
}
codeStream.Emit(ILOpcode.add);
switch (_method.Kind)
{
case ArrayMethodKind.Get:
codeStream.Emit(ILOpcode.ldobj, _emitter.NewToken(_elementType));
break;
case ArrayMethodKind.Set:
codeStream.EmitLdArg(_rank + argStartOffset);
codeStream.Emit(ILOpcode.stobj, _emitter.NewToken(_elementType));
break;
case ArrayMethodKind.AddressWithHiddenArg:
break;
}
codeStream.Emit(ILOpcode.ret);
codeStream.EmitLdc(0);
codeStream.EmitLabel(rangeExceptionLabel); // Assumes that there is one "int" pushed on the stack
codeStream.Emit(ILOpcode.pop);
MethodDesc throwHelper = context.GetHelperEntryPoint("ThrowHelpers", "ThrowIndexOutOfRangeException");
codeStream.EmitCallThrowHelper(_emitter, throwHelper);
if (typeMismatchExceptionLabel != null)
{
codeStream.EmitLabel(typeMismatchExceptionLabel);
codeStream.EmitCallThrowHelper(_emitter, context.GetHelperEntryPoint("ThrowHelpers", "ThrowArrayTypeMismatchException"));
}
}
}
}
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