Ryujinx/ARMeilleure/Instructions/InstEmitFlowHelper.cs
Ficture Seven 2421186d97
Generalize tail continues (#1298)
* Generalize tail continues

* Fix DecodeBasicBlock

`Next` and `Branch` would be null, which is not the state expected by
the branch instructions. They end up branching or falling into a block
which is never populated by the `Translator`. This causes an assert to
be fired when building the CFG.

* Clean up Decode overloads

* Do not synchronize when branching into exit block

If we're branching into an exit block, that exit block will tail
continue into another translation which already has a synchronization.

* Remove A32 predicate tail continue

If `block` is not an exit block then the `block.Next` must exist (as
per the last instruction of `block`).

* Throw if decoded 0 blocks

Address gdkchan's feedback

* Rebuild block list instead of setting to null

Address gdkchan's feedback
2020-06-18 13:37:21 +10:00

380 lines
14 KiB
C#

using ARMeilleure.Decoders;
using ARMeilleure.IntermediateRepresentation;
using ARMeilleure.State;
using ARMeilleure.Translation;
using ARMeilleure.Translation.PTC;
using System;
using static ARMeilleure.Instructions.InstEmitHelper;
using static ARMeilleure.IntermediateRepresentation.OperandHelper;
namespace ARMeilleure.Instructions
{
static class InstEmitFlowHelper
{
public const ulong CallFlag = 1;
public static void EmitCondBranch(ArmEmitterContext context, Operand target, Condition cond)
{
if (cond != Condition.Al)
{
context.BranchIfTrue(target, GetCondTrue(context, cond));
}
else
{
context.Branch(target);
}
}
public static Operand GetCondTrue(ArmEmitterContext context, Condition condition)
{
Operand cmpResult = context.TryGetComparisonResult(condition);
if (cmpResult != null)
{
return cmpResult;
}
Operand value = Const(1);
Operand Inverse(Operand val)
{
return context.BitwiseExclusiveOr(val, Const(1));
}
switch (condition)
{
case Condition.Eq:
value = GetFlag(PState.ZFlag);
break;
case Condition.Ne:
value = Inverse(GetFlag(PState.ZFlag));
break;
case Condition.GeUn:
value = GetFlag(PState.CFlag);
break;
case Condition.LtUn:
value = Inverse(GetFlag(PState.CFlag));
break;
case Condition.Mi:
value = GetFlag(PState.NFlag);
break;
case Condition.Pl:
value = Inverse(GetFlag(PState.NFlag));
break;
case Condition.Vs:
value = GetFlag(PState.VFlag);
break;
case Condition.Vc:
value = Inverse(GetFlag(PState.VFlag));
break;
case Condition.GtUn:
{
Operand c = GetFlag(PState.CFlag);
Operand z = GetFlag(PState.ZFlag);
value = context.BitwiseAnd(c, Inverse(z));
break;
}
case Condition.LeUn:
{
Operand c = GetFlag(PState.CFlag);
Operand z = GetFlag(PState.ZFlag);
value = context.BitwiseOr(Inverse(c), z);
break;
}
case Condition.Ge:
{
Operand n = GetFlag(PState.NFlag);
Operand v = GetFlag(PState.VFlag);
value = context.ICompareEqual(n, v);
break;
}
case Condition.Lt:
{
Operand n = GetFlag(PState.NFlag);
Operand v = GetFlag(PState.VFlag);
value = context.ICompareNotEqual(n, v);
break;
}
case Condition.Gt:
{
Operand n = GetFlag(PState.NFlag);
Operand z = GetFlag(PState.ZFlag);
Operand v = GetFlag(PState.VFlag);
value = context.BitwiseAnd(Inverse(z), context.ICompareEqual(n, v));
break;
}
case Condition.Le:
{
Operand n = GetFlag(PState.NFlag);
Operand z = GetFlag(PState.ZFlag);
Operand v = GetFlag(PState.VFlag);
value = context.BitwiseOr(z, context.ICompareNotEqual(n, v));
break;
}
}
return value;
}
public static void EmitCall(ArmEmitterContext context, ulong immediate)
{
EmitJumpTableBranch(context, Const(immediate));
}
private static void EmitNativeCall(ArmEmitterContext context, Operand nativeContextPtr, Operand funcAddr, bool isJump = false)
{
context.StoreToContext();
if (isJump)
{
context.Tailcall(funcAddr, nativeContextPtr);
}
else
{
OpCode op = context.CurrOp;
Operand returnAddress = context.Call(funcAddr, OperandType.I64, nativeContextPtr);
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);
// We need to clear out the call flag for the return address before comparing it.
context.BranchIfTrue(lblContinue, context.ICompareEqual(context.BitwiseAnd(returnAddress, Const(~CallFlag)), nextAddr));
context.Return(returnAddress);
}
}
private static void EmitNativeCall(ArmEmitterContext context, Operand funcAddr, bool isJump = false)
{
EmitNativeCall(context, context.LoadArgument(OperandType.I64, 0), funcAddr, isJump);
}
public static void EmitVirtualCall(ArmEmitterContext context, Operand target)
{
EmitVirtualCallOrJump(context, target, isJump: false);
}
public static void EmitVirtualJump(ArmEmitterContext context, Operand target, bool isReturn)
{
EmitVirtualCallOrJump(context, target, isJump: true, isReturn: isReturn);
}
private static void EmitVirtualCallOrJump(ArmEmitterContext context, Operand target, bool isJump, bool isReturn = false)
{
if (isReturn)
{
context.Return(target);
}
else
{
EmitJumpTableBranch(context, target, isJump);
}
}
public static void EmitTailContinue(ArmEmitterContext context, Operand address, bool allowRejit = false)
{
// Left option here as it may be useful if we need to return to managed rather than tail call in future.
// (eg. for debug)
bool useTailContinue = true;
if (useTailContinue)
{
if (context.HighCq)
{
// If we're doing a tail continue in HighCq, reserve a space in the jump table to avoid calling back
// to the translator. This will always try to get a HighCq version of our continue target as well.
EmitJumpTableBranch(context, address, true);
}
else
{
if (allowRejit)
{
address = context.BitwiseOr(address, Const(CallFlag));
}
Operand fallbackAddr = context.Call(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFunctionAddress)), address);
EmitNativeCall(context, fallbackAddr, true);
}
}
else
{
context.Return(address);
}
}
private static void EmitNativeCallWithGuestAddress(ArmEmitterContext context, Operand funcAddr, Operand guestAddress, bool isJump)
{
Operand nativeContextPtr = context.LoadArgument(OperandType.I64, 0);
context.Store(context.Add(nativeContextPtr, Const(NativeContext.GetCallAddressOffset())), guestAddress);
EmitNativeCall(context, nativeContextPtr, funcAddr, isJump);
}
private static void EmitBranchFallback(ArmEmitterContext context, Operand address, bool isJump)
{
address = context.BitwiseOr(address, Const(address.Type, (long)CallFlag)); // Set call flag.
Operand fallbackAddr = context.Call(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFunctionAddress)), address);
EmitNativeCall(context, fallbackAddr, isJump);
}
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);
}
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);
}
}
}
}