public static Operand EmitReadIntAligned(ArmEmitterContext context, Operand address, int size)
{
if ((uint)size > 4)
{
throw new ArgumentOutOfRangeException(nameof(size));
}
Operand isUnalignedAddr = EmitAddressCheck(context, address, size);
Operand lblFastPath = Label();
context.BranchIfFalse(lblFastPath, isUnalignedAddr, BasicBlockFrequency.Cold);
// The call is not expected to return (it should throw).
context.Call(typeof(NativeInterface).GetMethod(nameof(NativeInterface.ThrowInvalidMemoryAccess)), address);
context.MarkLabel(lblFastPath);
Operand physAddr = EmitPtPointerLoad(context, address, null, write: false);
return(size switch
{
0 => context.Load8(physAddr),
1 => context.Load16(physAddr),
2 => context.Load(OperandType.I32, physAddr),
3 => context.Load(OperandType.I64, physAddr),
_ => context.Load(OperandType.V128, physAddr)
});
private static void EmitReadInt(ArmEmitterContext context, Operand address, int rt, int size)
{
Operand lblSlowPath = Label();
Operand lblEnd = Label();
Operand physAddr = EmitPtPointerLoad(context, address, lblSlowPath, write: false, size);
Operand value = default;
switch (size)
{
case 0: value = context.Load8(physAddr); break;
case 1: value = context.Load16(physAddr); break;
case 2: value = context.Load(OperandType.I32, physAddr); break;
case 3: value = context.Load(OperandType.I64, physAddr); break;
}
SetInt(context, rt, value);
if (!context.Memory.Type.IsHostMapped())
{
context.Branch(lblEnd);
context.MarkLabel(lblSlowPath, BasicBlockFrequency.Cold);
EmitReadIntFallback(context, address, rt, size);
context.MarkLabel(lblEnd);
}
}
private static void EmitReadInt(ArmEmitterContext context, Operand address, int rt, int size)
{
Operand lblSlowPath = Label();
Operand lblEnd = Label();
Operand isUnalignedAddr = EmitAddressCheck(context, address, size);
context.BranchIfTrue(lblSlowPath, isUnalignedAddr);
Operand physAddr = EmitPtPointerLoad(context, address, lblSlowPath, write: false);
Operand value = null;
switch (size)
{
case 0: value = context.Load8(physAddr); break;
case 1: value = context.Load16(physAddr); break;
case 2: value = context.Load(OperandType.I32, physAddr); break;
case 3: value = context.Load(OperandType.I64, physAddr); break;
}
SetInt(context, rt, value);
context.Branch(lblEnd);
context.MarkLabel(lblSlowPath, BasicBlockFrequency.Cold);
EmitReadIntFallback(context, address, rt, size);
context.MarkLabel(lblEnd);
}
private static void EmitReadVector(
ArmEmitterContext context,
Operand address,
Operand vector,
int rt,
int elem,
int size)
{
Operand isUnalignedAddr = EmitAddressCheck(context, address, size);
Operand lblFastPath = Label();
Operand lblSlowPath = Label();
Operand lblEnd = Label();
context.BranchIfFalse(lblFastPath, isUnalignedAddr);
context.MarkLabel(lblSlowPath);
EmitReadVectorFallback(context, address, vector, rt, elem, size);
context.Branch(lblEnd);
context.MarkLabel(lblFastPath);
Operand physAddr = EmitPtPointerLoad(context, address, lblSlowPath);
Operand value = null;
switch (size)
{
case 0:
value = context.VectorInsert8(vector, context.Load8(physAddr), elem);
break;
case 1:
value = context.VectorInsert16(vector, context.Load16(physAddr), elem);
break;
case 2:
value = context.VectorInsert(vector, context.Load(OperandType.I32, physAddr), elem);
break;
case 3:
value = context.VectorInsert(vector, context.Load(OperandType.I64, physAddr), elem);
break;
case 4:
value = context.Load(OperandType.V128, physAddr);
break;
}
context.Copy(GetVec(rt), value);
context.MarkLabel(lblEnd);
}
public static Operand EmitReadIntAligned(ArmEmitterContext context, Operand address, int size)
{
if ((uint)size > 4)
{
throw new ArgumentOutOfRangeException(nameof(size));
}
Operand physAddr = EmitPtPointerLoad(context, address, null, write: false, size);
return(size switch
{
0 => context.Load8(physAddr),
1 => context.Load16(physAddr),
2 => context.Load(OperandType.I32, physAddr),
3 => context.Load(OperandType.I64, physAddr),
_ => context.Load(OperandType.V128, physAddr)
});
public static void EmitDynamicTableCall(ArmEmitterContext context, Operand tableAddress, Operand address, bool isJump)
{
// Loop over elements of the dynamic table. Unrolled loop.
Operand endLabel = Label();
Operand fallbackLabel = Label();
void EmitTableEntry(Operand entrySkipLabel)
{
// Try to take this entry in the table if its guest address equals 0.
Operand gotResult = context.CompareAndSwap(tableAddress, Const(0L), address);
// Is the address ours? (either taken via CompareAndSwap (0), or what was already here)
context.BranchIfFalse(entrySkipLabel,
context.BitwiseOr(
context.ICompareEqual(gotResult, address),
context.ICompareEqual(gotResult, Const(0L)))
);
// It's ours, so what function is it pointing to?
Operand targetFunctionPtr = context.Add(tableAddress, Const(8L));
Operand targetFunction = context.Load(OperandType.I64, targetFunctionPtr);
// Call the function.
// We pass in the entry address as the guest address, as the entry may need to be updated by the
// indirect call stub.
EmitNativeCallWithGuestAddress(context, targetFunction, tableAddress, isJump);
context.Branch(endLabel);
}
// Currently this uses a size of 1, as higher values inflate code size for no real benefit.
for (int i = 0; i < JumpTable.DynamicTableElems; i++)
{
if (i == JumpTable.DynamicTableElems - 1)
{
// If this is the last entry, avoid emitting the additional label and add.
EmitTableEntry(fallbackLabel);
}
else
{
Operand nextLabel = Label();
EmitTableEntry(nextLabel);
context.MarkLabel(nextLabel);
// Move to the next table entry.
tableAddress = context.Add(tableAddress, Const((long)JumpTable.JumpTableStride));
}
}
context.MarkLabel(fallbackLabel);
EmitBranchFallback(context, address, isJump);
context.MarkLabel(endLabel);
}
private static Operand EmitPtPointerLoad(ArmEmitterContext context, Operand address, Operand lblFallbackPath)
{
Operand pte = Const(context.Memory.PageTable.ToInt64());
int bit = MemoryManager.PageBits;
do
{
Operand addrPart = context.ShiftRightUI(address, Const(bit));
bit += context.Memory.PtLevelBits;
if (bit < context.Memory.AddressSpaceBits)
{
addrPart = context.BitwiseAnd(addrPart, Const(addrPart.Type, context.Memory.PtLevelMask));
}
Operand pteOffset = context.ShiftLeft(addrPart, Const(3));
if (pteOffset.Type == OperandType.I32)
{
pteOffset = context.ZeroExtend32(OperandType.I64, pteOffset);
}
Operand pteAddress = context.Add(pte, pteOffset);
pte = context.Load(OperandType.I64, pteAddress);
}while (bit < context.Memory.AddressSpaceBits);
if (!context.Memory.HasWriteWatchSupport)
{
Operand hasFlagSet = context.BitwiseAnd(pte, Const((long)MemoryManager.PteFlagsMask));
context.BranchIfTrue(lblFallbackPath, hasFlagSet);
}
Operand pageOffset = context.BitwiseAnd(address, Const(address.Type, MemoryManager.PageMask));
if (pageOffset.Type == OperandType.I32)
{
pageOffset = context.ZeroExtend32(OperandType.I64, pageOffset);
}
Operand physAddr = context.Add(pte, pageOffset);
return(physAddr);
}
private static Operand EmitPtPointerLoad(ArmEmitterContext context, Operand address, Operand lblSlowPath)
{
int ptLevelBits = context.Memory.AddressSpaceBits - 12; // 12 = Number of page bits.
int ptLevelSize = 1 << ptLevelBits;
int ptLevelMask = ptLevelSize - 1;
Operand pte = Ptc.State == PtcState.Disabled
? Const(context.Memory.PageTablePointer.ToInt64())
: Const(context.Memory.PageTablePointer.ToInt64(), true, Ptc.PageTablePointerIndex);
int bit = PageBits;
do
{
Operand addrPart = context.ShiftRightUI(address, Const(bit));
bit += ptLevelBits;
if (bit < context.Memory.AddressSpaceBits)
{
addrPart = context.BitwiseAnd(addrPart, Const(addrPart.Type, ptLevelMask));
}
Operand pteOffset = context.ShiftLeft(addrPart, Const(3));
if (pteOffset.Type == OperandType.I32)
{
pteOffset = context.ZeroExtend32(OperandType.I64, pteOffset);
}
Operand pteAddress = context.Add(pte, pteOffset);
pte = context.Load(OperandType.I64, pteAddress);
}while (bit < context.Memory.AddressSpaceBits);
context.BranchIfTrue(lblSlowPath, context.ICompareLess(pte, Const(0L)));
Operand pageOffset = context.BitwiseAnd(address, Const(address.Type, PageMask));
if (pageOffset.Type == OperandType.I32)
{
pageOffset = context.ZeroExtend32(OperandType.I64, pageOffset);
}
return(context.Add(pte, pageOffset));
}
public static void EmitJumpTableBranch(ArmEmitterContext context, Operand address, bool isJump = false)
{
if (address.Type == OperandType.I32)
{
address = context.ZeroExtend32(OperandType.I64, address);
}
// TODO: Constant folding. Indirect calls are slower in the best case and emit more code so we want to avoid them when possible.
bool isConst = address.Kind == OperandKind.Constant;
long constAddr = (long)address.Value;
if (!context.HighCq)
{
// Don't emit indirect calls or jumps if we're compiling in lowCq mode.
// This avoids wasting space on the jump and indirect tables.
// Just ask the translator for the function address.
EmitBranchFallback(context, address, isJump);
}
else if (!isConst)
{
// Virtual branch/call - store first used addresses on a small table for fast lookup.
int entry = context.JumpTable.ReserveDynamicEntry(isJump);
int jumpOffset = entry * JumpTable.JumpTableStride * JumpTable.DynamicTableElems;
Operand dynTablePtr = Const(context.JumpTable.DynamicPointer.ToInt64() + jumpOffset);
EmitDynamicTableCall(context, dynTablePtr, address, isJump);
}
else
{
int entry = context.JumpTable.ReserveTableEntry(context.BaseAddress & (~3L), constAddr, isJump);
int jumpOffset = entry * JumpTable.JumpTableStride + 8; // Offset directly to the host address.
// TODO: Relocatable jump table ptr for AOT. Would prefer a solution to patch this constant into functions as they are loaded rather than calculate at runtime.
Operand tableEntryPtr = Const(context.JumpTable.JumpPointer.ToInt64() + jumpOffset);
Operand funcAddr = context.Load(OperandType.I64, tableEntryPtr);
EmitNativeCallWithGuestAddress(context, funcAddr, address, isJump); // Call the function directly. If it's not present yet, this will call the direct call stub.
}
}
public static void EmitJumpTableBranch(ArmEmitterContext context, Operand address, bool isJump = false)
{
if (address.Type == OperandType.I32)
{
address = context.ZeroExtend32(OperandType.I64, address);
}
// TODO: Constant folding. Indirect calls are slower in the best case and emit more code so we want to
// avoid them when possible.
bool isConst = address.Kind == OperandKind.Constant;
long constAddr = (long)address.Value;
if (!context.HighCq)
{
// Don't emit indirect calls or jumps if we're compiling in lowCq mode. This avoids wasting space on the
// jump and indirect tables. Just ask the translator for the function address.
EmitBranchFallback(context, address, isJump);
}
else if (!isConst)
{
// Virtual branch/call - store first used addresses on a small table for fast lookup.
int entry = context.JumpTable.ReserveDynamicEntry(isJump);
int jumpOffset = entry * JumpTable.JumpTableStride * JumpTable.DynamicTableElems;
Operand dynTablePtr;
if (Ptc.State == PtcState.Disabled)
{
dynTablePtr = Const(context.JumpTable.DynamicPointer.ToInt64() + jumpOffset);
}
else
{
dynTablePtr = Const(context.JumpTable.DynamicPointer.ToInt64(), true, Ptc.DynamicPointerIndex);
dynTablePtr = context.Add(dynTablePtr, Const((long)jumpOffset));
}
EmitDynamicTableCall(context, dynTablePtr, address, isJump);
}
else
{
int entry = context.JumpTable.ReserveTableEntry(context.BaseAddress & (~3L), constAddr, isJump);
int jumpOffset = entry * JumpTable.JumpTableStride + 8; // Offset directly to the host address.
Operand tableEntryPtr;
if (Ptc.State == PtcState.Disabled)
{
tableEntryPtr = Const(context.JumpTable.JumpPointer.ToInt64() + jumpOffset);
}
else
{
tableEntryPtr = Const(context.JumpTable.JumpPointer.ToInt64(), true, Ptc.JumpPointerIndex);
tableEntryPtr = context.Add(tableEntryPtr, Const((long)jumpOffset));
}
Operand funcAddr = context.Load(OperandType.I64, tableEntryPtr);
// Call the function directly. If it's not present yet, this will call the direct call stub.
EmitNativeCallWithGuestAddress(context, funcAddr, address, isJump);
}
}
private static void EmitTableBranch(ArmEmitterContext context, Operand guestAddress, bool isJump)
{
context.StoreToContext();
if (guestAddress.Type == OperandType.I32)
{
guestAddress = context.ZeroExtend32(OperandType.I64, guestAddress);
}
// Store the target guest address into the native context. The stubs uses this address to dispatch into the
// next translation.
Operand nativeContext = context.LoadArgument(OperandType.I64, 0);
Operand dispAddressAddr = context.Add(nativeContext, Const((ulong)NativeContext.GetDispatchAddressOffset()));
context.Store(dispAddressAddr, guestAddress);
Operand hostAddress;
// If address is mapped onto the function table, we can skip the table walk. Otherwise we fallback
// onto the dispatch stub.
if (guestAddress.Kind == OperandKind.Constant && context.FunctionTable.IsValid(guestAddress.Value))
{
Operand hostAddressAddr = !context.HasPtc ?
Const(ref context.FunctionTable.GetValue(guestAddress.Value)) :
Const(ref context.FunctionTable.GetValue(guestAddress.Value), new Symbol(SymbolType.FunctionTable, guestAddress.Value));
hostAddress = context.Load(OperandType.I64, hostAddressAddr);
}
else
{
hostAddress = !context.HasPtc ?
Const((long)context.Stubs.DispatchStub) :
Const((long)context.Stubs.DispatchStub, Ptc.DispatchStubSymbol);
}
if (isJump)
{
context.Tailcall(hostAddress, nativeContext);
}
else
{
OpCode op = context.CurrOp;
Operand returnAddress = context.Call(hostAddress, OperandType.I64, nativeContext);
context.LoadFromContext();
// Note: The return value of a translated function is always an Int64 with the address execution has
// returned to. We expect this address to be immediately after the current instruction, if it isn't we
// keep returning until we reach the dispatcher.
Operand nextAddr = Const((long)op.Address + op.OpCodeSizeInBytes);
// Try to continue within this block.
// If the return address isn't to our next instruction, we need to return so the JIT can figure out
// what to do.
Operand lblContinue = context.GetLabel(nextAddr.Value);
context.BranchIf(lblContinue, returnAddress, nextAddr, Comparison.Equal, BasicBlockFrequency.Cold);
context.Return(returnAddress);
}
}
public static void EmitStoreExclusive(
ArmEmitterContext context,
Operand address,
Operand value,
bool exclusive,
int size,
int rs,
bool a32)
{
if (size < 3)
{
value = context.ConvertI64ToI32(value);
}
if (exclusive)
{
void SetRs(Operand value)
{
if (a32)
{
SetIntA32(context, rs, value);
}
else
{
SetIntOrZR(context, rs, value);
}
}
Operand arg0 = context.LoadArgument(OperandType.I64, 0);
Operand exAddrPtr = context.Add(arg0, Const((long)NativeContext.GetExclusiveAddressOffset()));
Operand exAddr = context.Load(address.Type, exAddrPtr);
// STEP 1: Check if we have exclusive access to this memory region. If not, fail and skip store.
Operand maskedAddress = context.BitwiseAnd(address, Const(address.Type, GetExclusiveAddressMask()));
Operand exFailed = context.ICompareNotEqual(exAddr, maskedAddress);
Operand lblExit = Label();
SetRs(exFailed);
context.BranchIfTrue(lblExit, exFailed);
// STEP 2: We have exclusive access, make sure that the address is valid.
Operand isUnalignedAddr = InstEmitMemoryHelper.EmitAddressCheck(context, address, size);
Operand lblFastPath = Label();
context.BranchIfFalse(lblFastPath, isUnalignedAddr);
// The call is not expected to return (it should throw).
context.Call(typeof(NativeInterface).GetMethod(nameof(NativeInterface.ThrowInvalidMemoryAccess)), address);
// STEP 3: We have exclusive access and the address is valid, attempt the store using CAS.
context.MarkLabel(lblFastPath);
Operand physAddr = InstEmitMemoryHelper.EmitPtPointerLoad(context, address, null, write: true);
Operand exValuePtr = context.Add(arg0, Const((long)NativeContext.GetExclusiveValueOffset()));
Operand exValue = size switch
{
0 => context.Load8(exValuePtr),
1 => context.Load16(exValuePtr),
2 => context.Load(OperandType.I32, exValuePtr),
3 => context.Load(OperandType.I64, exValuePtr),
_ => context.Load(OperandType.V128, exValuePtr)
};
Operand currValue = size switch
{
0 => context.CompareAndSwap8(physAddr, exValue, value),
1 => context.CompareAndSwap16(physAddr, exValue, value),
_ => context.CompareAndSwap(physAddr, exValue, value)
};
// STEP 4: Check if we succeeded by comparing expected and in-memory values.
Operand storeFailed;
if (size == 4)
{
Operand currValueLow = context.VectorExtract(OperandType.I64, currValue, 0);
Operand currValueHigh = context.VectorExtract(OperandType.I64, currValue, 1);
Operand exValueLow = context.VectorExtract(OperandType.I64, exValue, 0);
Operand exValueHigh = context.VectorExtract(OperandType.I64, exValue, 1);
storeFailed = context.BitwiseOr(
context.ICompareNotEqual(currValueLow, exValueLow),
context.ICompareNotEqual(currValueHigh, exValueHigh));
}
else
{
storeFailed = context.ICompareNotEqual(currValue, exValue);
}
SetRs(storeFailed);
context.MarkLabel(lblExit);
}
else
{
InstEmitMemoryHelper.EmitWriteIntAligned(context, address, value, size);
}
}
public static void EmitStoreExclusive(
ArmEmitterContext context,
Operand address,
Operand value,
bool exclusive,
int size,
int rs,
bool a32)
{
if (size < 3)
{
value = context.ConvertI64ToI32(value);
}
if (exclusive)
{
// We overwrite one of the register (Rs),
// keep a copy of the values to ensure we are working with the correct values.
address = context.Copy(address);
value = context.Copy(value);
void SetRs(Operand value)
{
if (a32)
{
SetIntA32(context, rs, value);
}
else
{
SetIntOrZR(context, rs, value);
}
}
Operand arg0 = context.LoadArgument(OperandType.I64, 0);
Operand exAddrPtr = context.Add(arg0, Const((long)NativeContext.GetExclusiveAddressOffset()));
Operand exAddr = context.Load(address.Type, exAddrPtr);
// STEP 1: Check if we have exclusive access to this memory region. If not, fail and skip store.
Operand maskedAddress = context.BitwiseAnd(address, Const(address.Type, GetExclusiveAddressMask()));
Operand exFailed = context.ICompareNotEqual(exAddr, maskedAddress);
Operand lblExit = Label();
SetRs(Const(1));
context.BranchIfTrue(lblExit, exFailed);
// STEP 2: We have exclusive access and the address is valid, attempt the store using CAS.
Operand physAddr = InstEmitMemoryHelper.EmitPtPointerLoad(context, address, null, write: true, size);
Operand exValuePtr = context.Add(arg0, Const((long)NativeContext.GetExclusiveValueOffset()));
Operand exValue = size switch
{
0 => context.Load8(exValuePtr),
1 => context.Load16(exValuePtr),
2 => context.Load(OperandType.I32, exValuePtr),
3 => context.Load(OperandType.I64, exValuePtr),
_ => context.Load(OperandType.V128, exValuePtr)
};
Operand currValue = size switch
{
0 => context.CompareAndSwap8(physAddr, exValue, value),
1 => context.CompareAndSwap16(physAddr, exValue, value),
_ => context.CompareAndSwap(physAddr, exValue, value)
};
// STEP 3: Check if we succeeded by comparing expected and in-memory values.
Operand storeFailed;
if (size == 4)
{
Operand currValueLow = context.VectorExtract(OperandType.I64, currValue, 0);
Operand currValueHigh = context.VectorExtract(OperandType.I64, currValue, 1);
Operand exValueLow = context.VectorExtract(OperandType.I64, exValue, 0);
Operand exValueHigh = context.VectorExtract(OperandType.I64, exValue, 1);
storeFailed = context.BitwiseOr(
context.ICompareNotEqual(currValueLow, exValueLow),
context.ICompareNotEqual(currValueHigh, exValueHigh));
}
else
{
storeFailed = context.ICompareNotEqual(currValue, exValue);
}
SetRs(storeFailed);
context.MarkLabel(lblExit);
}
else
{
InstEmitMemoryHelper.EmitWriteIntAligned(context, address, value, size);
}
}