[TestCase(X64Register.R14)] // Never allocated in this method without a requirement
public void Register_requirement_is_respected(X64Register required)
{
var method = new LowMethod <X64Register>();
method.Locals.Add(new LowLocal <X64Register>(SimpleType.Bool));
method.Locals.Add(new LowLocal <X64Register>(SimpleType.Bool, required));
method.Blocks.Add(new LowBlock
{
Instructions =
{
new LowInstruction(LowOp.LoadInt, 0, 0, 0, 1), // Load 1 -> #0
new LowInstruction(LowOp.Move, 1, 0, 0, 0), // Move #0 -> #1
new LowInstruction(LowOp.Compare, 0, 1, 0, 0), // Compare #1, #0
new LowInstruction(LowOp.Return, 0, 0, 0, 0) // Return #0
},
Predecessors = Array.Empty <int>(),
Successors = Array.Empty <int>()
});
var(rewritten, allocationMap) = X64RegisterAllocator.Allocate(method);
AssertDump(rewritten, @"
LB_0:
LoadInt 0 0 1 -> 0
Move 0 0 0 -> 1
Compare 1 0 0 -> 0
Return 0 0 0 -> 0");
Assert.That(allocationMap.Get(0).localIndex, Is.EqualTo(0));
Assert.That(allocationMap.Get(1).localIndex, Is.EqualTo(1));
Assert.That(allocationMap.Get(0).location.IsSet, Is.True);
Assert.That(allocationMap.Get(1).location.IsSet, Is.True);
Assert.That(allocationMap.Get(1).location.Register, Is.EqualTo(required));
}
/// <summary>
/// Emits a full-width pop instruction with the specified destination register.
/// </summary>
public void EmitPop(X64Register dest)
{
if (dest >= X64Register.Xmm0)
{
throw new InvalidOperationException("Pop on XMM register");
}
_disassemblyWriter?.WriteLine($"{Indent}pop {GetRegisterName(dest, 8)}");
var(encodedReg, needB) = GetRegisterEncoding(dest);
// The opcode is encoded exactly as push, except for the 0x8 bit
if (needB)
{
_outputStream.WriteByte(0x41);
}
_outputStream.WriteByte((byte)(0x58 | encodedReg));
}
/// <summary>
/// Emits a full-width push instruction with the specified source register.
/// </summary>
public void EmitPush(X64Register src)
{
if (src >= X64Register.Xmm0)
{
throw new InvalidOperationException("Push on XMM register");
}
_disassemblyWriter?.WriteLine($"{Indent}push {GetRegisterName(src, 8)}");
var(encodedReg, needB) = GetRegisterEncoding(src);
if (needB)
{
// New registers need a REX.B prefix
_outputStream.WriteByte(0x41);
}
_outputStream.WriteByte((byte)(0x50 | encodedReg));
}