public void Allocate(BasicBlock <IRInstrList> block)
{
var blockLiveness = liveness[block];
var instrLiveness = LivenessAnalysis.ComputeLiveness(block, blockLiveness);
var pool = RegisterPool.Create(baseOffset, globalVars);
for (var i = 0; i < block.Content.Count; i++)
{
var instr = block.Content[i];
pool.CheckLiveness(instrLiveness[instr]);
// Allocates
if (instr.Operand1 != null)
{
instr.Operand1 = AllocateOperand(instr.Operand1, pool);
}
if (instr.Operand2 != null)
{
instr.Operand2 = AllocateOperand(instr.Operand2, pool);
}
}
if (pool.SpillOffset - 1 > LocalSize)
{
LocalSize = pool.SpillOffset - 1;
}
baseOffset = pool.SpillOffset;
}
private IIROperand AllocateOperand(IIROperand operand, RegisterPool pool)
{
if (operand is IRVariable)
{
var variable = (IRVariable)operand;
StackSlot?slot;
var reg = AllocateVariable(pool, variable, out slot);
if (reg != null)
{
return new IRRegister(reg.Value)
{
SourceVariable = variable,
Type = variable.Type
}
}
;
variable.Annotation = slot.Value;
return(new IRPointer
{
Register = IRRegister.BP,
Offset = slot.Value.Offset,
SourceVariable = variable,
Type = variable.Type
});
}
return(operand);
}
public static RegisterPool Create(int baseOffset, Dictionary <IRVariable, StackSlot> globalVars)
{
var pool = new RegisterPool();
pool.regAlloc = new IRVariable[NumRegisters];
pool.spillVars = new Dictionary <IRVariable, StackSlot>(globalVars);
pool.SpillOffset = baseOffset;
return(pool);
}
IIROperand AllocateOperand(IIROperand operand, RegisterPool pool)
{
if (operand is IRVariable)
{
var variable = (IRVariable)operand;
StackSlot?slot;
var reg = AllocateVariable(pool, variable, out slot);
if (reg != null)
{
return new IRRegister(reg.Value)
{
SourceVariable = variable,
Type = variable.Type
}
}
;
variable.Annotation = slot.Value;
return(new IRPointer {
Register = IRRegister.BP,
Offset = slot.Value.Offset,
SourceVariable = variable,
Type = variable.Type
});
}
return(operand);
}
VMRegisters?AllocateVariable(RegisterPool pool, IRVariable var, out StackSlot?stackSlot)
{
stackSlot = pool.CheckSpill(var);
if (stackSlot == null)
{
var allocReg = var.Annotation == null ? (VMRegisters?)null : (VMRegisters)var.Annotation;
if (allocReg == null)
{
allocReg = pool.Allocate(var);
}
if (allocReg != null)
{
if (var.Annotation == null)
{
var.Annotation = allocReg.Value;
}
return(allocReg);
}
// Spill variable
stackSlot = pool.SpillVariable(var);
}
return(null);
}
}
private VMRegisters?AllocateVariable(RegisterPool pool, IRVariable var, out StackSlot?stackSlot)
{
stackSlot = pool.CheckSpill(var);
if (stackSlot == null)
{
var allocReg = var.Annotation == null ? (VMRegisters?)null : (VMRegisters)var.Annotation;
if (allocReg == null)
{
allocReg = pool.Allocate(var);
}
if (allocReg != null)
{
if (var.Annotation == null)
{
var.Annotation = allocReg.Value;
}
return(allocReg);
}
// Spill variable
stackSlot = pool.SpillVariable(var);
}
return(null);
}
